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{"created":"2022-01-31T13:09:58.075386+00:00","id":"lit29465","links":{},"metadata":{"contributors":[{"name":"Todd, Robert Bentley","role":"author"}],"detailsRefDisplay":"London: Longman, Brown, Green and Longmans","fulltext":[{"file":"a0001.txt","language":"en","ocr_en":"tue\nCYCLOP\u00c6DIA\nOF\nANATOMY and PHYSIOLOGY.\nVOL. IV.","page":0},{"file":"a0002.txt","language":"en","ocr_en":"London :\nSpottiswoodes and Shaw,\nNew-street-Square.","page":0},{"file":"a0003.txt","language":"en","ocr_en":"THE\nCYCLOP\u00c6DIA\nOF\nANATOMY and PHYSIOLOGY.\nEDITED BY\nROBERT B. TODD, M.D. F.R.S.\nFELLOW OF THE ROYAL COLLEGE OF PHYSICIANS;\nPHYSICIAN TO KING\u2019S COLLEGE HOSPITAL; AND PROFESSOR OF PHYSIOLOGY AND OF GENERAL AND MORBID ANATOMY IN KING\u2019S COLLEGE,\nLONDON, ETC. ETC.\nYOL. IY.\nP L A--W1U\nLONDON:\nLONGMAN, BROWN, GREEN, AND LONGMANS.\n1852.","page":0},{"file":"a0005.txt","language":"en","ocr_en":"THE\nCYCLOP\u00c6DIA\nOF\nANATOMY and PHYSIOLOGY.\nEDITED BY\nROBERT B. TODD, M.D. F.R.S.\nFELLOW OF THE RO\u00cfAL COLLEGE OF PHYSICIANS;\nPHYSICIAN TO KING\u2019S COLLEGE HOSPITAL ; AND FORMERLY PROFESSOR OF PHYSIOLOGY AND OF GENERAL AND MORBID ANATOMY IN KING\u2019S COLLEGE,\nLONDON, ETC. ETC.\nYOL. IY.\nPLA \u2014WRI\n1847\u20141852\nLONDON\nLONGMAN, BROWN, GREEN, LONGMANS, & ROBERTS.","page":0},{"file":"a0006.txt","language":"en","ocr_en":"\n\n\n\n\n","page":0},{"file":"a0007.txt","language":"en","ocr_en":"CONTRIBUTORS\nJOHN ADAMS, Esq.\nSurgeon to the London Hospital, and Lecturer on Anatomy.\nROBERT ADAMS, Esq.\nSurgeon to the Richmond Hospital, and Lecturer on Anatomy and Surgery, Dublin.\nB. ALCOCK, M.B. Dublin.\nW. P. ALISON, M.D. F.R.S.E.\nProf, of the Pract. of Med. in the Univ. of Edin. &c.\nJOHN ANDERSON, Esq. M.E.S. Richmond. J. APJOHN, M.D. M.R.I.A.\nProf, of Chem. to the Royal Coll, of Surgeons, Ireland,\nVICTOR AUDOUIN, M.D. Paris.\nProfesseur-Administrateur auMus\u00e9e d\u2019HistoireNaturelle.\nB. G.BABINGTON, M.D. F.R.S.\nPhysician to Guy\u2019s Hospital.\nTHOMAS BELL, Sec. R.S.\nProfessor of Zoology in King\u2019s College, London.\nCHARLES BENSON, M.D. M.R.I.A.\nProf, of Med. to the Royal Coll, of Surgeons, Ireland.\nJ. BISHOP, F.R.S. London.\nJOHN BOSTOCK, M.D. V.P.R.S. London. W. BOWMAN, F.R.S.\nAssistant-Surgeon to the King\u2019s College Hospital and to the Royal Ophthalmic Hospital, Moorfields, and Professor of Physiology, King\u2019s College, London.\nJ. E. BOWMAN, Esq.\nProf, of Practical Chemistry in King\u2019s Coll. London.\nW. T. BRANDE, F.R.S.\nProfessor of Chemistry to the Royal Institution, &c.\nJ. E. BRENAN, M.D. (the late).\nW. BRINTON, M.D.\nMedical Tutor in King\u2019s College, London.\nW. B. CARPENTER, M.D. F.R.S.\nProf, of Med. Jurisprudence, Univ. Coll. Lond.\nJOHN COLDSTREAM, M.D.\nFell. Roy. Coll. Phys. Edinb. &c.\nW. WHITE COOPER, F.R.C.S.\nSen. Surgeon to the North London Eye Infirmary, Ophthalmic Surgeon to St. Mary\u2019s Hospital.\nDAVID CRAIGIE, M.D. F.R.S.E.\nFellow of the Royal Coll, of Physicians, Edinb, &c.\nT. BLIZARD CURLING, F.R.S.\nLect. on Surg. and Surg. to the Lond. Hospital.\nG.\tP. DESHAYES, M.D. Paris.\nA. T. S. DODD, Esq. (the late).\nI. DRUMMOND, M. D. Edinburgh.\nP. M DUNCAN, M.D.\nPhysician to the fefifftm\u00e7y, Colchester.\nH.\tDUTROCHET, M.D.\nW. F. EDWAftDS, M.D. F.R.S. (the lat#>\nH. MILNE EDWARDS, M.D.\nProf, of Nat. History to the College of Henry IV., arid to the Central School of Arts and Manufactures, Paris.\nARTHUR FARRE, M.D. F.R.S.\nProfessor of Midwifery in King\u2019s College, and Physician Accoucheur to King\u2019s College Hospital.\nHEINRICH FREY, M. D.\nProf, of Gen. and Comp. Anat. at Zurichi\nR. D. GRAINGER, F.R.S.\nLect. on Anat. and Phys. at St. Thomas\u2019s Hospital.\nR. E. GRANT, M.D. F.R.S. L. & E.\nFell, of the Roy. Coll, of Physicians, Edinb. and Prof, of Comp. Anatomy and Zoology in Univ. College, &c.\nW A. GUY, M.D.\nProf. For. Med. King\u2019s College, London, and Physician to King\u2019s College Hospital.\nM. HALL, M.D. F.R.S. L. & E. London. HENRY HANCOCK, Esq.\nLect. on Surgery at, and Surgeon to, the Charing-Cross Hospital.\nROBERT HARRISON, M.D. M.R.I.A.\nProf, of Anat. and Surg. in the Univ. of Dublin.\nJOHN HART, M.D. M R.I.A.\nProf, of Anat. in the Royal Coll, of Surg. Dublin.\nA. HIGGINSON, Esq. Liverpool.\nJ. HUTCHINSON, M.D., London.\nARTHUR JACOB, M.D. M.R.I.A.\nProfessor of Anatomy and Physiology to the Royal College of Surgeons in Ireland.\nGEORGE JOHNSON, M.D.\nAssistant Physician to King\u2019s Col. Hosp. Lond.\nC. HANDFIELD JONES, M.D. F.R.S.\nPhysician to St. Mary\u2019s Hospital, London.\nT. RUPERT JONES, Esq.\nAssistant Sec. Geolog. Soc. London.\nT. RYMER JONES, F.R.S.\nProf, of Comp. Anat. in King\u2019s College, London.\nT. WHARTON JONES, F.R.S. London.\nW. SENHOUSE KIRKES, M.D.\nSAMUEL LANE, Esq.\nLecturer on Anatomy, St. George's Hospital, London\nEDWIN LANKESTER, M.D. F.R.S.\nLecturer on Materia Medica and Botany.\nJ. LEUCKARDT, M.D. G\u00f6ttingen.\nA. K\u00d6LLIKER,\nProf, of Anat. and Phys. in the Udiv. of Wurzburg.\nF. T. MACDOUGALL, Esq.\nBENJ. M\u2018DOWEL, M.D.\nLecturer on Anatomy at the Richmond Hospital, and Physician to the Whitworth Hospital, Dublin.\nJOSEFH MACLISE, Esq., London.\nJOHN MALYN, Esq. (the late).","page":0},{"file":"a0008.txt","language":"en","ocr_en":"CONTRIBUTORS.\nROBERT MAYNE, M.D.\nLect. on Anat. & Phys. Richmond Hospital, Dublin.\nW. A. MILLER, M.D. F.R.S.\nProfessor of Chemistry in King\u2019s College, London.\nW. F. MONTGOMERY, M.D. M.R.I.A.\nFellow of, and Professor of Midwifery to, the King and Queen\u2019s College of Physicians in Ireland.\nGEORGE NEWPORT, F.R.S. F.L.S.\nR.\tOWEN, F.R.S. F.G.S.\nHunterian Professor of Comparative Anatomy and Physiology to the Royal College of Surgeons, London.\nJAMES PAGET, F.R.S.\nLect. on Anat. & Phys. St. Bartholomew\u2019s Hospital.\nRICHARD PARTRIDGE, F.R.S.\nProf, of Descrip, and Surg. Anat. King\u2019s College. Surgeon to King\u2019s College Hospital, London.\nBENJAMIN PHILLIPS, F.R.S. London.\nSurgeon to the Westminster Hospital.\nSIMON ROOD PITTARD, Esq.\nAssociate of King\u2019s College, London.\nW. H. PORTER, Esq.\nProf, of Surgery to the Royal Coll, of Surg. in Ireland.\nG.\tOWEN REES, M.D. F.R.S.\nAssistant Physician to Guy\u2019s Hospital.\nJ. REID, M.D. (the late).\nProf, of Medicine in the University of St. Andrews.\nEDWARD RIGBY, M.D. F.L.S.\nLect. on Midwifery at St. Bartholomew\u2019s Hospital.\nJ. FORBES ROYLE, M.D. F.R.S. F.G.S.\nProf, of Materia Medica in King\u2019s College, London,\nH.\tHYDE SALTER, M.D/\nDemonstrator of Anatomy in King\u2019s Coll., Lond.\nS.\tJAMES A. SALTER, M.B., London.\nHENRY SEARLE, Esq. London.\nW. SHARPEY, M.D. F.R.S.\nProf, of Anat. and Physiol, in Univ. Coll. London.\nJOHN SIMON, F.R.S.\nSurgeon to and Lect. on Path. St. Thomas\u2019s Hosp.\nJ. Y. SIMPSON, M.D.\nFellow of the Royal College of Physicians, and Professor of Midwifery in the University of Edinburgh.\nSAMUEL SOLLY, F.R.S.\nSurgeon to St. Thomas\u2019s Hospital.\nGABRIEL STOKES, M.D.\nJ. A. SYMONDS, M.D.\nPhysician to the Bristol General Hospital.\nALLEN THOMSON, M.D. F.R.S.\nProf, of Anatomy in the University of Glasgow.\nJOHN TOMES, Esq. F.R.S.\nSurgeon-Dentist to the Middlesex Hospital.\nWM. TREW, Esq.\nW. VROLIK,\nProf. Anat. and Phys. at the Athen\u00e6um of Amsterdam\nRUDOLPH WAGNER, M.D.\nProf, of Anat. and Phys. intheRoy.Univ. G\u00f6ttingen\nW. H. WALSHE, M.D.\nProf. Med. Univ. Coll. London, Physician to University College Hospital, &c.\nN. WARD, Esq.\nDemonstrator of Anatomy, and Assistant Surgeon to the London Hospital.\nR. WILLIS, M.D.\nW. J. ERASMUS WILSON, F.R. S.\nConsulting Surgeon to the St. Paneras Infirmary.\nJ. WOOD, Esq.\nDemonstrator of Anatomy in King\u2019s Coll., Lond.","page":0},{"file":"a0009content.txt","language":"en","ocr_en":"CONTENTS OF THE FOURTH VOLUME\nPleura \t\t. S. R. Pittard, Esq.\tPage 1\nPolygastria \t\t, Professor R. Jones\t2\nPolypifera \t\t, Professor R. Jones\t18\nPopliteal Region ...\tW. Trew, Esq.\t60\nPorifera \t\tProfessor R. Jones\t64\nProducts, Adventitious Dr. Walshe \t\t\t\t71\nProstate \t\tJ. Adams, Esq. ...\t146\nProtein \t\t, Prof. J.E. Bowman\t162\nPteropoda\t\tProfessor R. Jones\t170\nPuise \t\t, Dr. Guy \t\t181\nQuadrumana \t\t\t, Professor Vrolik ...\t194\nRadial Artery\t\t, Dr. Brinton \t\t221\nRadio-ulnar Articu-' lation\t| Dr. Brinton \t\t228\nRen \t\tDr. Johnson\t\t231\nReptilia \t\t\tProfessor R. Jones\t264\nRespiration \t\tDr. John Reid\t325\nRodentia \t\tProfessor R. Jones\t368\nRotifera \t\tDr. Lankester \t\t396\nSaliva \t\tDr. Owen Rees\t415\nSalivary Glands \t\tN. Ward, Esq. ...\t422\nScapular Region\tDr. M\u2018 Dowel \t\t433\nScrotum \t\tDr. Brinton\t\t438\nSecretion\t\tDr. Carpenter \t\t439\nSemen \t\tC Drs. Wagner and )\t472\n\tL Leuckhardt J\t\nSensation\t\tDr. Todd \t\t508\nSensibility \t\t\tDr. Todd \t\t510\nSerous and Synovial*] Membranes\tJ\tj-\u00fcr. Brinton\t\t511\nSesamoid Bones \t\tS. R. Pittard, Esq.\t541\nSeventh Pair of Nerves Dr. Brinton\t\t\t543\nShell\t\tDr. Carpenter\t\t556\nShoulder J oint (Nor- -1 mal Anatomy)\tJ\t| Dr. Mi Dowel \t\t571\nShoulder Joint (Abnormal Conditions of)\tj- Robert Adams, Esq. 577\t\nSixth Pair of Nerves\tDr. Brinton \t\t621\nSkeleton \t\tJoseph Maclise, Esq.\t622\nSleep...\t\tDr. Carpenter \t\t677\nSmell \t\tDr. Carpenter\t\t697\nSoftening and Indu--] ration\tJ\t[\u25a0 Dr. P. M. Duncan\t703\nPage\nSolipeds\t........... Professor\tR. Jones\t713\nSpinal\tAccessory, ^\t^.......... ^\nNerve\tJ\nSpinal Nerves.............. N. Ward, Esq.. 750\nSpleen ......... Professor\tK\u00f6lliker\t771\nStatistics,\tMedical\t...\tDr. Guy\t......... 801\nSubclavian Arteries Dr. MlDowel .......... 814\nSupra-renal Capsules Prof Heinrich Frey 827\nSweat .............. Dr. G. O. Rees ... 841\nSymmetry ........... S. R. Pittard, Esq. 845\nSympathy ........... Dr. Todd............. 852\nSynovia ............ Dr. G. O. Rees ... 856\nTaste .............. Dr. Carpenter ....... 856\nTeeth .............. Professor Owen ... 864\nTemperament......... Dr. Todd............. 935\nTemporo - maxillary 1 _\nArticulations\t) & R Pittard, Esq. 937\nTeratology ......... Professor Vrolik ... 942\nTesticle ........... T. B. Curling, Esq. 976\nThorax ............. Dr. Hutchinson....1016\nThymus Gland ....... Dr. Handfield Jones 1087\nThyroid Gland ...... Dr. Handfield Jones 1102\nTibio-fibular Articu- \"|\nlations\t\\Dr-M\u2018Dowel\t 1118\nTongue ............. Dr. Hyde Salter ...1120\nTouch .............. Dr. Carpenter .......1163\nTunicata ........... Professor R. Jones 1185\nUrethra ............. John Adams, Esq. 1244\nUrine .............. Dr. G. Owen Rees 1268\nVarieties of Mankind Dr. Carpenter .......1294\nVein................ S. Jas.A.Salter,Esq.l367\nVenous System ...... Dr. M Dowel .........1403\nVesicula Prostatica... Professor Leuckhardt 1415 Vesicul\u00e6 S\u00e9minales S. R. Pittard, Esq. 1429\nVision..............( W- White Cooper, j 143\u00df\nEsq.\tJ\nVital Statistics.... Dr. Guy ..........1469\nVoice .............. John Bishop, Esq. 1475\nWrist Joint (Normal *| _\nAnatomy..........)Dr-\t.1505\nWrist Joint (Abnor- ~|\nmal Conditions of) ] R Adams\u2019 Es\u00bb \u2022\u2022\u20221508","page":0},{"file":"a0010.txt","language":"en","ocr_en":"\ni\n","page":0},{"file":"p0001.txt","language":"en","ocr_en":"THE\nCYCLOP\u00c6DIA\nOF\nANATOMY AND PHYSIOLOGY.\nPLEURA is the name given to the serous sac of the lung and the cavity containing it. Th\u00e9re are two pleural sacs, one for the right lung and right side of the thorax, the other for the left lung and left side of the thorax. These two sacs being apposed and adherent to one another in the middle line, form there a median, antero-posterior, vertical septum, called the mediastinum, which divides the thoracic cavity into two lateral compartments. Each pleura is, like all other serous membranes, with one exception, a shut sac ; and there being but one organ contained in each pleural cavity, and that organ being of a tolerably simple form, the well-known comparison of a double nightcap, expressive of the manner in which a serous sac lines the interior of a cavity and invests the exterior of the viscus contained in it, is extremely apt in the case of these sacs lining the chest and covering the lungs. Of the two surfaces of the sacs, the inner one is everywhere free and the outer everywhere adherent ; such in fact is universally the case with all serous membranes. Each pleura invests its respective lung, and lines the moiety of the thoracic cavity to which it belongs, in the simplest manner possible, as simply and accurately as though it were a coating of paint, dipping into the fissures of the lungs and into the acute angles formed by the cost\u00e6 with the arching diaphragm in the most neat and accurate manner. It only remains then, in order to complete our description of the course of these membranes, to examine the manner in which they pass from the parietes to the viscus. It is thus:\u2014the two pleur\u00e6, above, below, behind, and in front, meet one another in or near the middle line,\nVOL. IV.\nand form the mediastinum above-mentioned ; between the layers of the mediastinum are situated the heart and great vessels and the termination of the trachea ; from these issue on each side a bronchus, pulmonary artery, pulmonary veins, &c. destined to the lung, w'hich, bound loosely together by areolar tissue, have received the appellation of the root of the lung; this root of the lung emerges from the mediastinum at about the middle of its posterior upper quarter, and is covered with a layer of the pleura, which thereby becomes conducted from this point of the mediastinum to the lung.\nThe term mediastinum is applied by some writers to the antero-posterior vertical septum of the chest, by others to the spaces occupied by the viscera situated between its layers ; in the latter senseof the term three mediastinaare enumerated \u2014anterior, posterior, and middle; the anterior, which is very large, is the space occupied by the heart in its pericardium, thymus gland, or its.re-mains, and phrenic nerves ; the middle contain\u00ab the bifurcation of the trachea, the arch of the aorta, the pulmonary and other great vessels ; the posterior contains the aorta, oesophagus, &c. All these organs, their position, &c. will be found described in other parts of this work ; their right and left aspects are invested by the right or left pleura respectively. It is in their larger interspaces only that the two pleur\u00e6 come into actual contact and adhesion with one another. The smaller interspaces are not intruded upon by the pleur\u00e6, but are occupied with areolar tissue and fat. In most of the lower (mammalian) animals, where the chest is deep and narrow, and in the human foetus, the two pleur\u00e6 come into adhesion with one ano-\nB","page":1},{"file":"p0002.txt","language":"en","ocr_en":"2\nPOLYGASTRIA.\nther in front of the heart; but in the adult human subject this is not the case, the pericardium coming into immediate contact with the anterior thoracic parietes. Also the pleurae are prevented by the adhesion of the pericardium to the diaphragm from adhering to one another below the heart. It is almost superfluous to state that the heart and pericardium encroach more upon the left pleural cavity than upon the right. The median thoracic septum of the human subject is able, partly on account of its small antero-posterior extent, to resist any considerable lateral displacement, such as might result from accumulation of effusion into one pleural cavity ; but in deep-chested animals it admits of displacement to such an extent that the whole of the chest may be filled with an effusion into one pleural cavity. In a Chetah, which died of pleurisy at the gardens of the Zoological Society, dissected by the author, the immediate cause of death was suffocation occasioned by effusion into the right pleura, which occupied the whole chest, and compressed the left lung, the left pleura being unaffected. The mediastinum may be regarded as a kind of mesentery to the heart, and in some reptiles it is very obviously seen to be a part of the great median mesentery wherein all the viscera are suspended. This great median mesentery of reptiles is attached to parietes in front as well as behind as far down as the falciform ligament of the liver; as though a fold of serous membrane had been pulled down by the umbilical vein. In some reptiles, as the chameleon, the anterior parietal attachment is continued even down to the small intestines, so that the stomach and part of the small intestine are enclosed between the layers of the mediastinum. The serial homology of this septum is obscured in Mammalia by the diaphragm being interposed between it and the other mesenteries.\nThe only fold or duplicature made by each pleura that is comparable to the mesenteries or omenta formed by the peritoneum is that called the broad ligament of the lung ( ligament um latum pulmonis). It is a fold carried downwards and backwards from the root of the lung. It may be described as having four edges, the upper one of which is attached along the lower aspect of the root of the lung; the outer one is attached to the inner aspect of the lung from its root to its lower border; the inner one is attached to the mediastinum from the root of the lung downwards and backwards to the oesophageal opening in the diaphragm ; the remaining edge is free and directed outwards, downwards, and backwards. Its inner or mediastinal attachment is by far the longest, so that its figure is four-sided, with one corner extremely drawn out or prolonged.\nThere are frequently found, especially about the pericardium, numerous pyriform masses of fat covered with pleura, like appendices epiploicse.\nThe outer surface of the pleura is but loosely adherent to the ribs and intercostal muscles; it is more firmly connected with- the diaphragm and pericardium, and still more firmly with the lungs. The adhesion of the two pleurae\nin the mediastinum is extremely loose in the human subject, large quantities of areolar tissue and frequently fat being interposed ; so that in many subjects they can hardly be said to come into immediate contact at all.\nThe pleura covering the ribs and that forming the ^mediastinum is strengthened by a fibrous layer/ but that covering the lungs is destitute of such fibres, and consequently extremely thin and delicate. The terms pleura pulmonal,is, pleura costalis, and pleura diaphragrnatiea, are applied respectively to those parts of the pleurae which are connected with the lungs, the ribs, and the diaphragm : and these expressions are frequently found extremely convenient.\nFrom the extreme frequency of abnormal adhesions of the apposed surfaces of the pleura it appears that this serous membrane is unusually liable to inflammation, which liability may be due to its being unusually exposed to external circumstances through its extreme proximity to the air in the lungs.\nThe pleura is peculiar to the class Mammalia. In Birds the lungs are adherent to the thoracic parietes ; and in Reptiles, there being no distinction of thorax and abdomen, they are invested by the peritoneum. To this, however, there is an exception in the Crocodilians, in which reptiles a rudimentary diaphragm exists. The pleurae of these animals are disposed around the outer, anterior, and posterior, but not the inner aspect of each lung; so that the lung seems to be adherent to the mediastinum.\n(Simon Rood Pittard.)\nPOLYGA STRIA. \u2014 A name applied by Professor Ehrenberg, of Berlin, to an immense class of microscopic animalcules which exist in countless millions in water of various kinds, both salt and fresh, more especially in such as contains decomposing animal or vegetable substances.\nMany forms of these beings are indescribably minute, some of them measuring not more than the 32,000th part of an inch in length, and all of them are of such tiny dimensions as to require the utmost penetration of the microscope and the most patient industry on the part of the observer to make out their organization. A few of the largest are, indeed, barely distinguishable by the unassisted eye; but, generally speaking, they are quite invisible; and had it not been for the invention of the microscope, we should, even at this day, have been ignorant of their existence.\nThe numbers in which these creatures abound baffles all expression. It has been ascertained, and the fact may easily be proved with a good microscope, that, possessing the dimensions above referred to, say the 24,000th part of an inch, many of these living atoms crowd the water in which they are found to such an extent that they are not separated from each other by a space greater than the size of their whole bodies; so that by a very little calculation it will be seen that a single drop of such water contains more of these active existences than there are human beings upon the surface of this globe. And when the mind reflects upon their","page":2},{"file":"p0003.txt","language":"en","ocr_en":"POLYGASTRIA.\nuniversal distribution wherever water is to be met with fit for their reception, it is impossible not to be overwhelmed with the contemplation of a scene so calculated to impress upon us the infinitude of the works of the Creator.\nOur knowledge of the class of animals under consideration dates from a very recent period. The earliest observers with the microscope, partly from the imperfection of their instruments, and partly from ignorance of any characteristic distinctions, were in the habit of grouping all the creatures of microscopic dimensions, which they perceived swimming in the water they examined, as belonging to the same category, under the name of \u201c Infusorial Animalcules,\u201d a title which consequently embraced creatures of the most dissimilar forms and habits, and even widely removed from each other in the scale of animal existences by their internal organization and general economy ; thus the Rotifera, the larv\u00e6 of insects, the gemmules of Polyps, and innumerable other minute creatures were confounded under the same denomination. It is to the researches of Ehrenberg, the great historiographer of these beings, that we are indebted for the breaking up of this chaotic assemblage, and the introduction of order where all was previously confusion and uncertainty.\nPrior to his discoveries naturalists denied the existence of any alimentary apparatus in the Infusoria, believing them to be nourished by a kind of imbibition, and regarding the granular bodies contained within them as being their eggs or young ones. Ehrenberg, however, by placing indigo, carmine, sap-green, and similar extremely pure coloured vegetable substances in the water containing them, soon found that the coloured material was readily admitted into the interior of the body, and there disposed in such a manner as to convince him that there were numerous receptacles in the interior of these little beings, which he considered as forming their nutritive apparatus; and having applied to them the name of stomachs, he was induced to establish a distinct class for creatures thus organised, and distinguished them from all other animals by the name of POLYGASTRIA.*\nThese stomachs he subsequently discovered to be variously arranged in different genera, and was consequently induced to make these variations in the construction of the alimentary apparatus a basis on which to erect a scheme for their further subdivision. This kind of nutritive system of organs he found presented itself under different forms ; in some species the stomachal cavities communicate separately with the oral orifice, so that there is no intestinal tube or passage of intercommunication between them : to such he has applied the term Anentera^ In all others there is a wide intestinal tube in the interior of the body, to the sides of which the numerous alimentary vesicles or reservoirs are appended,\n* ttoX\u00f9\u00e7, many ; yacrr>jp, a stomach.\nt <*, piiv. ; ivTEpov, intestine.\nterminating by an anal orifice : these have been named from this circumstance Enterodela.*\nThe Enterodelous Polygastria are again divisible :\u2014\n1st. Into those in which the intestinal tube is disposed in a circular form in the interior of the body of the animalcule, winding round so that the mouth and anus, are contiguous. (CYCLOCCELA.f)\n2nd. Into those in which the intestine traverses the body of the animalcule, passing along its longitudinal axis, and presenting two orifices completely distinct and opposite to each other ; that which is anterior forming the mouth, the posterior the anus: such are characterized as Orthoc\u0153la.J;\n3rd. Such as have a winding or twisted intestine, which never passes in a direct line through the long axis of the body : these genera are named Campyloc\u00abela.\u00a7\nSuch a classification, founded entirely on the anatomical arrangement of one set of organs, Ehrenberg acknowledges would be quite contrary to the established rules of zoology, were it not that the external characters of these animalcules are most exactly conformable with the structure of the alimentary canal ; but finding that the Polygastria are thus resolvable into very natural families, he proceeds to classify them in the following manner :\u20141|\nFamily 1. \u2014 Monadin id\u00e6 (Monadid\u00e6). Polygastric animals, without intestinal canal, without external shell, body uniform, dividing by simple spontaneous fissure into two, but by cross divisions into four or several individuals.\nMonas.\nUvella, (1 ,fig. 1.)\nPolytoma, (2, fig. 1.)\nMicroglena, (3,fig- 1.)\nPhacelomonas.\nGlenomorum.\nDoxococcus.\nChilomonas.\nBodo, (4, fig. 1.)\nFamily 2.\u2014Cryptomonadinid\u00e6. Polygastric animals, presenting all the characters of the Monadinid\u00e6, or at least deprived of the characteristic features of other families, and individually enveloped in a soft or slightly indurated shell.\nCryptomonas.\nOphidomonas.\nPorocentrum.\nLagenella, (5, fig. 1.)\nCryptoglena.\nTrachelomonas.\nFamily 3.\u2014Yolvocijm id\u00e6. Polygastric animals, without intestinal canal, without external\n* Evrspov, intestine ; SijXo\u00e7, manifest.\nt xijuXo\u00e7, a circle; xoTxo\u00e7, large intestine.\nf opOoj, straight ; koTxo\u00e7, intestine.\n\u00a7 xctfATrvXo\u00e7, crooked ; jcoTxo\u00e7, intestine.\n|| In the following list it will be perceived we have omitted altogether the numerous families of Baccillari\u00e6 and kindred forms, being by no means satisfied as to their claims to rank as members of the animal creation. They stand, indeed, very dubiously between the domains of zoology and botany.\nB 2","page":3},{"file":"p0004.txt","language":"en","ocr_en":"4\nPOLYGASTRIA.\nappendages, and with th\u00e7 body uniform, similar to the monads, but provided with an external envelope or shell, and dividing by complete spontaneous fissure beneath the common envelope into a number of animals which take the form of a polypary. At length the envelope becomes ruptured, and gives passage to the divided animals, which in their turn renew the same process of developement.\nGyges.\nPandorina.\nGonium, (7, 8, fig. 1.)\nSyn crypta.\nSynura.\nUroglena.\nEudorina, (9, 10, \u00dfg. 1.)\nChlamidomonas.\nSph\u00e6rosira.\nVolvox, (fig. 3.)\nFamily 4.\u2014Vibrionid\u00e6. Animals either distinctly or most probably polygastric; filiform ; without alimentary canal ; without shell or external appendages ; with the uniform body of Monads; associated in filiform chains in consequence of imperfect spontaneous (transverse ) division.\nBacterium.\nVibrio, (1, 2, 3, 4, 5, fig. 5.)\nSpiroch\u00e6ta.\nSpirillum.\nSpirodiscus.\nFamily 5.\u2014Closterinid\u00e6. Animals distinctly or most probably polygastric, without alimentary canal, and without external appendages ; body uniform, resembling the Crypto-monadinid\u00e6 in their envelope or shell, and dividing, together with their envelope, by spontaneous, transverse fissure, into a bacilliform or fusiform polypary ; provided with moveable papillae situated in the aperture of the shell.\nClosterium, (6, 7, fig. 5.)\nFamily 6. \u2014 Astasiead\u00e6. Animals evidently or apparently polygastric, without alimentary canal, without external appendages or shell ; changing their form to caudate or ecaudate at pleasure; body with a single aperture.\nAstasia, (1, fig. 6.)\nAmblyophis, (2, fig. 6.)\nEuglena, (3, fig. 6.)\nChlorogonium, (4, fig. 6.)\nColacium, (5, fig. 6.)\nDistigma.\nFamily 7.\u2014Dinobryina. Animals distinctly or apparently polygastric ; without intestinal canal; body with a single aperture; without external appendages; changing their form at will, and invested with a shell.\nEpipyxis.\nFamily 8. \u2014 Amoebaead\u00e6 (Proteiform Animalcules). Polygastric animalcules without alimentary canal; body with a single opening, furnished with variable processes, the shape of which changes at will ; without a shell.\nAmoeba, (7, 8, 9, 10, 11, 12, 13, fig. 6.)\nFamily 9.\u2014Arcellinid\u00e6. (Capsule Animalcules). Animal polygastric, anenterous, loricated ; body multiform, furnished with changeable foot-like appendages, covered with a univalve urceolate or scutellate shell, with a\nsingle aperture. = Amoeba enclosed in an urceolate or scutellate shell.\nDifflugia, (1, fig- 7.)\nArcella, (2, fig. 7.)\nCyphidium, (3, fig. 7.)\nFa?nily 11. \u2014 Cyclidinid\u00e6 (Disk Animalcules). Animals polygastric, anenterous, provided with appendages in the form of cilia or set\u00e6 ; destitute of shell.\nCyclidium.\nPantotrichum.\nChaetomonas.\nFamily 12.\u2014 Peridinaead\u00e6 (Wreath Animalcules). Animals visibly or probably polygastric, anenterous, loricated, vibrating ; having set\u00e6 and cilia dispersed over the body or shell often in the form of a zone or crown ; shell with a single opening.\nCh\u00e6totyphla.\nCh\u00e6toglena.\nPeridinium.\nGlenodinium.\nFamily 13. \u2014 Vorticellinid\u00e6 (Fell Animalcule). Animals polygastric, having a distinct intestinal tube, with two openings, the oral and anal apertures being distinct, but situated in a depression common to both ; without shell; either solitary and free, or fixed and frequently associated, developing themselves by imperfect spontaneous division, and frequently assuming the form of beautiful little bunches.\nStentor, (fig. 8.)\nTrichodina.\nUrocentrum.\nVorticella, (fig. 9.)\nCarchesium.\nEpistylis.\nOpercularia.\nZoothamnium.\nFamily 14. \u2014 Ophrydinid\u00e6 (Loricated Bell Animalcules). Polygastric animalcules, having a distinct intestinal tube, the apertures of the mouth and anus being distinct, although situated in the same fossa ; loricated ; solitary or aggregated. ( \u2014 Vorticellina loricata.)\nOphrydium, (fig. 10.)\nTintinnus.\nVaginicola, (9, fig.tl.)\nCothurnia.\nFamily 15. \u2014 Encheliad\u00e6 ( Bolling Animalcules). Animals polygastric ; having a distinct intestinal canal, the apertures of the mouth and anus being situated at the opposite extremities of the longitudinal axis of the body; without a shell.\nEnchelis, (1,2, 3,4, 5, fig. 11.)\nDisoma, (6, 7, jig. 11.)\nActinophrys.\nTrie hod iscus.\nPodophrya.\nTrichoda.\nLachrymaria, (8, fig. 11.)\nLeucophrys, (1, fig. 12.)\nHolophrya.\nProrodon (2, fig. 12.)\nFamily 16. \u2014 Coeepin id\u00e6 (Box Animalcules). Polygastric animalcules, having a distinct intestinal canal, the mouth and anus","page":4},{"file":"p0005.txt","language":"en","ocr_en":"POLYGASTRIA.\nbeing situated at the opposite extremities of the body; loricated. = Encheliad\u00e6 furnished with a shell.\nColeps, (1, 2, fig. 13.)\nFamily 17. \u2014\u25a0 Trachelinjd\u00e6 (Neck Animalcules). Animals polygastric, furnished with a distinct intestinal canal, having an oral and an anal opening, but of these the anal opening only is terminal ; without shell.\nTrachelius, (3, 4,5, fig. 13.)\nLoxodes.\nBursaria.\nSpirostoma.\nPhialina.\nGlaucoma.\nChilodon.\nNassula, (1, fig. 16.)\nFamily 18. \u2014 Ophryocercinid\u00e6 (Swan Animalcules). Animals polygastric ; having a distinct intestinal tube, furnished with two openings, that of the mouth only being terminal ; without a shell.\nTrachelocerca, (3, 4, fig. 16.)\nFamily 19. \u2014 Aspjdiscinid\u00e6 (Shield Animalcules). Polygastric, loricated, animalcules ; having an intestinal canal furnished with two orifices, of which one only, viz. the anus, is terminal.\nAspidisca.\nFamily 20. \u2014 Colpodead\u00e6 (Breast Animalcules). Animals polygastric ; without a shell ; intestinal canal distinct, with two openings, neither of which is terminal.\nColpoda, (2, 3,fig. 18.)\nParamecium, (1, 4, fig. 18.)\nAmphileptus, (2, fig. 16.)\nCJroleptus.\nOphryoglena.\nFamily 21. \u2014 Oxytrichinid\u00e6 (Hackle Animalcules.) Animals polygastric; without shell ; having an intestinal canal with two distinct orifices, neither of which is terminal; provided with vibrating cilia, and also with styles or uncini, which are not vibratile.\nOxytricha.\nCeratidium.\nKerona.\nUrostyla.\nStylonychia.\nFamily 22. \u2014 Euplotid\u00e6. (Boat Animalcules.) Animals polygastric, loricated ; with a distinct alimentary canal having two orifices, neither being terminal. = Aspidisca with neither orifice terminal, or Oxytricha provided with a shell.\nDiscocephalus.\nChlamidodon.\nHimantophorus.\nEuplotes, (fig. 19.)\nAll the above families are grouped by Ehrenberg under the following orders and sections, which, as it will facilitate the observations of the microscopist, as well as be a convenient guide to us in studying the economy of these little beings, we will subjoin in a tabular form, premising that the illustrious naturalist of Berlin found it advisable to separate the Poly-gastria into two parallel series, one comprising all such as were destitute of a shell (Nuda),\nthe other embracing those which are furnished with such a covering (Loricata).\nANENTERA.\nThis includes all animalcules which possess neither an internal nutritive tube nor an anal orifice, the mouth being in communication with several nutritive vesicles. These may be divided into the following sections :\u2014\n1 st Section. Gymnica.\nAnimalcules whose body has no external cilia nor pseudopediform prolongations.\nNuda.\tLoricata.\nMonadina.\tCryptomonadina.\nVibrio.\tClosterina.\n2d Section. Epitricha.\nExterior of the body ciliated or furnished with set\u00e6 and without pseudopediform prolongations.\nNuda.\nCyclidina.\n3d Section.\nLoricata. Peridin\u00e6a.\n?SEUDOPODIA.\nBody provided with variable pseudopediform prolongations.\nNuda.\tI\tLoricata.\nAmoeba.\tj\tBacillana.\nSecond Division.\u2014ENTERODELA.\nThis division includes all animalcules having an internal digestive canal provided with a mouth and anal opening.\n4th Section. Anopisthia.\nMouth and anus contiguous.\nNuda.\t1\tLoricata.\nVorticellina.\t|\tOphridina.\n5th Section. ENANTroTRETa.\nMouth and anus terminal and opposite ; reproduction by transverse division.\nNuda. Enchelia.\n6th Section.\nLoricata. Colepina. Allotreta.\nMouth and anus terminal and opposite, as in the last section ; reproduction by longitudinal and transverse division.\nNuda.\tI\tLoricata.\nTrachelina.\t|\tAspidiscina.\n7th Section. Katotreta.\nMouth and anus not terminal ; reproduction as in last section.\nNuda. Kolpodea. Oxytrichina.\nLoricata.\nEuplota.\nTaking the above classification for our guidance, we must now proceed to investigate more minutely the organization of the strange animals included in this extensive series.\nLocomotion.\u2014Although no special locomotive apparatus has as yet been discovered in the family of Monads, this perhaps depends rather upon our deficient means of investigation than upon their absence. Attentive observation shews that every true Monad is furnished with a minute filiform proboscis, (1, 2, 3, fig\u25a0 1>) which, as it constantly exhibits an un-dulatory or vibratory motion, has been mistaken by some observers for a ciliary apparatus. Sometimes two of these organs are present, but this cannot be regarded as an essential characteristic feature, seeing that during the process of spontaneous fissure an animalcule which previously had only one proboscis, becomes","page":5},{"file":"p0006.txt","language":"en","ocr_en":"6\nPOLYGASTRIA.\nfurnished with two preparatory to its separation into two individuals. In some species, however, two are constantly present. These proboscides may possibly discharge a double function, and perform the duty both of locomotive and of prehensile organs with which to collect nourishment.\nIn the Cryptoiponadinid\u00e6 likewise one or two filiform proboscides, similar to the above, seem to be the locomotive organs ; and the vibratile apparatus that serves for the movements of the Volvoces is entirely composed of similar structures belonging to the individual animalcules that constitute the compound bodies of these wonderful beings.\nAmongst the Vibrionid\u00e6 the locomotion is of a very different character. In the true Vibrios it is performed by a kind of meandering or undulating movement, the fibre-like compound body of the animal bending and straightening itself alternately, the cause of which seems to depend upon a stronger binding together and subsequent relaxation of the individual animalcules, so that these seem to displace one another. In Bacterium the contraction is weaker, so that no undulating movement is produced, although the creature swims straight forward.\nIn the family Closterina (6, 7,\u00dfg. 5) the locomotive organs consist of numerous short, soft, conical papill\u00e6, situated near the openings of the shell at the two opposite extremities of the animal ; they are placed upon the inner side, and can be protruded but a very little way from the shell.\nIn the family Amoeba no special locomotive organs are met with. The round, gelatinous, and highly contractile bodies of these creatures have the capability of thrusting out at will foot-like processes from any part of their body, by the assistance of which they manage to move about. A similar mode of progression is met with in the Arcellinid\u00e6. In all the higher forms of Polygastric Infusoria locomotion is effected by means of cilia variously distributed over different parts of the body, but their position in different genera will be described when speaking of the external forms of the different families.\nThese cilia are described by Ehrenberg to be minute hairs arising from a thick bulbous basis, upon which they execute a rotatory motion, some of them being continuous with their basis, while others are only articulated thereunto ; of these the former kind exists in Stylo-nychia mytilus, and the latter in Paramecium aurelia.\nIn addition to the cilia some forms of animalcules ( Oxytrichina) possess seta, which are likewise stiff moveable hairs, but which are without any power of vibration; these organs are used in standing and climbing. Sometimes they are without any thickened basis, as in Aciinophrys; generally they are pointed, but occasionally have a knob at the end.\nA fourth set of locomotive organs are the styli. These are thick straightset\u00e6, which in some forms of animalcules are attached like the tail feathers of a bird to the hinder part of the body of\nthe animalcule : such styli do not vibrate like cilia, neither are they implanted in a bulb-like basis, nor bend like hooks, but serve merely as instruments of support, or are useful in climbing the stems of aquatic plants.\nLastly, many races are furnished with uncini or hooklets ; these are merely bent, hook-like seta, which, being thick and strong, and situated upon the ventral surface of the animalcule, seem to take the place of feet : they do not vibrate, but are implanted into a bulb-like root, which permits them to be moved in all directions; and although they are not articulated, they resemble very much the limbs of articulated animals.\nSo various, however, are the forms of the different families of Polygastric animalcules, that the above general view of their locomotive organs gives but a very imperfect idea of this part of their economy; and it will, therefore, be necessary, before we proceed further, to describe more at length some of the most interesting genera belonging to the class, for so strange and remarkable is the organisation of some of them that no generalisation would answer our present purpose. Some are single and isolated individuals, moving freely wherever they list ; others are strangely compounded of aggregations of numerous animalcules associated into one common body, all of which must cooperate in rowing about the microcosm which they collectively form ; some are affixed to highly irritable stems, whereby they are attached to various foreign bodies ; some are naked, others covered with shells: in short, nothing but a rapid glance at the whole group will enable us satisfactorily to discuss the many curious circumstances discovered in connection with their history.\nThe family Monadinid\u00e6 embraces numerous animalcules, which, however different in external appearance, are evidently related to each other in all essential parts of their structure.\nThe Monads, properly so called, are so small that the utmost penetration of the miscroscope is insufficient to display their outward form with any degree of distinctness, much less to reveal their internal structure, some of them being not larger than from the 1,000th to the 3,000th of a line, or the 36,000th part of an inch in diameter. Under the highest powers of the microscope they have the appearance of almost invisible globular active specks, swimming about with the greatest facility, and never impinging against each other during the rapid dance that they continually execute. Their numbers are absolutely beyond human appreciation, as may be readily understood from the following computation of the multitudes sometimes met with.\nThe Monas crepusculum, found in infusions of putrid flesh, crowds the drop of water in which it is found to such an extent that there seems to be no interspace whatever between the individual animalcules. Supposing these animalcules to be, as is generally the case, 2^\u00f6\u00f6th of a line in diameter, their number will then amount, in a drop of water of the size of","page":6},{"file":"p0007.txt","language":"en","ocr_en":"POLYGASTRIA.\n7\na single cubic line, to eight thousand millions, and a cubic inch of such water containing 1728 cubic lines, will be peopled with thirteen billions eight hundred and twenty-four millions of these living and active beings ! ! !\nIt has been possible to detect, even in these smallest of nature\u2019s works, an apparatus that seems to perform the functions of an instrument of progression. This consists in one or sometimes two filaments of extreme tenuity, which resemble somewhat the tail of a tadpole ; here, however, the organ performs the functions of a proboscis, being appended to that part of the body which advances first in swimming. The shape of the Monads is not always globose, but sometimes egg-shaped, pear-shaped, elongated, or fusiform. In Monas tingens we have\nFig. 1.\n1. Uvella glaucoma. 2. Polytoma uvella, 3. Mi-croglena monadina. 4. Dodo socialis. 5. Lagenella euchlora. 6. The same crushed, showing its shell. 7. Gonium pectorale. 8. Gonium pectorale, breaking up into its component animalcules. 9. Eudorina. 10. One of the animalcules comprising Eudorina detached. 11, 12, 13. Developement of Volvox.\nan example of the last form, and also of the manner in which they are sometimes found associated by their tails into beautiful groups, their double proboscides being all protruded externally.\nThis faculty of clustering together is still better exemplified in the genus XJvella, (1, fig. 1,) which somewhat resembles a transparent mulberry rolling itself about at will, whence the name \u201c grape monad,\u201d which these animalcules bear. In Polytoma (2, fig. 1) this clustered appearance is due to the fact that the original animalcule is continually dividing into a greater and still greater number, which, at last breaking loose from each other, become solitary and independent.\nSome animalcules of this family, as Chilo-monas destruens, live in the interior of dead Rotifers and other minute beings, in which locality they seem to revel luxuriously ; whilst others, as Bodo, (4, fig. 1,) are met with in the intestinal canal of many living animals,* from the fly and the earth-worm up to fishes and even men. One species (B. ranarum) seems particularly partial to the intestines of Frogs, in the contents of which it is usually found. Many species of this genus are furnished with long tails, by the aid of which\n* Ehrenberg, Infusionsthierchen.\nthey are bound together in bunches of very beautiful appearance, as represented in the figure.\nIn the Cryptomonads, (5, fig. 1,) which seem to be merely Monads invested with a shell, the proboscis is of a similar character; but these animalcules are never found associated in bunches.\nPerhaps few more beautiful objects exist in nature than the next group of animalcules belonging to the Monadine type. These are the Volvocinidse, embracing several genera composed of numerous Monads, associated together and connected by a common envelope, which constitutes a kind of compound polypary or monadary, as it has been recently called, through which the proboscides of the component Monads are exserted.\nIn Gonium, (7, 8, fig. 1,) one of the simplest forms belonging to this family, the common body resembles a minute squareshaped flattened tablet, so transparent as to be detected with great difficulty, in which the green Monads are set like the gems in the breastplate of the Jewish high-priest, from which circumstance one species, G. pectorale, has been named.\nThe organisation of Gonium pectorale, as far as it has been made out, seems to be as follows :\u2014The mantle or proper covering of each individual animalcule, which can only be properly examined after the division of the little tablet, is neither four-cornered nor tablelike, but pretty nearly round, and in the form of a lacerna, which the animalcules can quit and renew again at intervals. The table-like investment of the compound body is produced by regularly repeated spontaneous fissure in the longitudinal, but not in the transverse direction, which is in fact only an imperfect division into single tablets. In a little tablet of this kind all the animalcules of which it is composed appear to be connected to each other by riband-like prolongations.\nIt is only jn Gonium pectorale that locomotive organs have been satisfactorily detected, presenting themselves under the usual form of two thread-like proboscides, appended to the mouth of each individual Monad entering into its composition. These are seen to be in constant motion, so as to have the appearance of cilia.\nEach individual animalcule inclosed in the common envelope of the compound being appears, moreover, to possess a distinct nutritive apparatus, consisting of transparent vesicles visible among the green matter that fills its interior ; but these have not yet been observed to fill themselves with colouring matter. Ehrenberg likewise supposes that each of the component animalcules of the Gonium contains the essential parts of a double sexual system, regarding the green-coloured particles in the body as eggs, and an opaque spot and contractile bladder, which is occasionally discernible, as the male apparatus; but these parts will be more particularly described hereafter.\nThe most beautiful animalcules belonging to the Volvocinid\u00e6 are the Volvoces, from which","page":7},{"file":"p0008.txt","language":"en","ocr_en":"8\nPOLYGASTRIA.\nthe family derives its name. These, which may readily be procured in summer time, are sufficiently large to be visible to the naked eye, and when examined with a microscope, even of very humble power, present a spectacle of indescribable beauty; turning continually upon their axes, and revolving majestically through the drop of water that forms their space, they have the appearance of so many microscopic worlds (fig. 2). The parietes of these elegant spheres are thin and pellucent as the walls of an air-bubble ; and in their interior, which is obviously fluid, may at times be seen rotating on their axes a second generation moving freely in the interior of their parent, and only awaiting the\nthe Volvox, and which he had previously regarded as the bulbous roots of locomotive cilia, he perceived in each corpuscle a bright red point, and moreover discerned that instead of its being a cilium which was appended thereto, it was a whip-like moveable proboscis exactly similar to that of the Monads described above ; and further observation convinced him that every green point was in reality a distinctly organised Monad, possessing mouth, eye, stomachs, generative apparatus, and, in fact, all the viscera attributed by Ehrenberg to the free Monadinid\u00e6, and that the Volvox was entirely made up of an association of similar individuals\n(fig\u2019 3).\nFig. 2.\nVolvox Globator, much magnified.\ndestruction of the original Volvox to escape from their imprisonment.\nIt was Ehrenberg * who first made the discovery that these beautiful living globes were not, as had until then been universally believed, single animalcules producing gemmules in the interior of their transparent bodies, which on arriving at maturity by their escape through the lacerated integument of the parent terminated its existence, but that they formed in reality the residences of numerous individuals living together in a wonderful community. This great observer had long remarked that the Volvoces appeared to take no food, neither were any of those vesicles discernible in their interior which in all other races of Infusoria he regards as the organs of nutrition\u2014a circumstance which, considering their very great size when compared with other races, was well calculated to arrest attention; and he soon found that the structure of their nutritive appa-tus lies much deeper and is of a far more delicate character than any one could have previously anticipated.\nOn attentively examining with glasses of high power (100*0 diameters) the minute green specks which stud the transparent covering of\nFig. 3.\nA portion of Volvox Globator still further magnified.\nHe further observed that in young specimens the component animalcules were perpetually undergoing spontaneous fissure, the result of which was the regular production of two, four, eight, sixteen, thirty-two, &c. distinct animalcules from one individual, until the resulting globe, i. e. the Volvox, was completely arrived at its natural dimensions.\nThe Volvox Globator may therefore be regarded as a hollow tegumentary vesicle, the origin of which is due to the incomplete spontaneous fissure of innumerable Monads, each of which is not more than 1.500in diameter, but all completely organised.\nFig. 4.\n* Abhandlungen der K\u00f6niglichen Academie der An individual monadine of Volvox Globator magnified Wissenschaften zu Berlin, Jahr 1833, p. 328.\t1000 diameters.","page":8},{"file":"p0009.txt","language":"en","ocr_en":"POLYGASTRIA.\nOn closer inspection it is seen that all the Monads, which are placed at regular distances, communicate with each other by delicate threads, which form a kind of reticulation in the common gelatinous skin-like integument of the compound body, or ptffypary, as it might be aptly called, out of which the contained animalcules only protrude their proboscides either in search of food or to row the general mass along.\nIt is easy to prove by flattening the Volvox between two plates of glass that its interior is only filled with water, in which sometimes there may be observed smaller volvoces swimming about, the products of the propagation of some of the constituent animalcules. These are not solitary young ones, but may already be seen to be composed of numerous individuals, formed by the continual division of the original from which they sprang.\nAnother mode of reproduction is by the laceration or division of the globe itself. When this takes place, either for the escape of the included Volvoces generated within, or from any other cause, the component Monads immediately prepare to leave their domiciles, and the individual animalcules become separated by the dissolution of the inter-communicating threads ; they then, by little and little, extricate themselves from the common gelatinous envelope, and creep out to commence an independent existence. The gelatinous polypary of the original Volvox in consequence speedily loses all its green spots ; and as every little point is active, moving its proboscis freely when it leaves the common globe, it may fairly be concluded that they have a power of independent existence, and that each is able to begin the construction of another compound Volvox as wonderful as that we have been considering.\nThe developement of the embryo of the Volvox is represented in 11, 12, 13, fig. 1. In 11, fig. 1, is represented the simplest condition of a granular mass containing a clear central spot, which in the course of a few hours assumes the condition represented in 12, fig. 1, by undergoing an imperfect spontaneous division. By a continued repetition of this division it becomes at last broken up, until it has the appearance shewn in 13, fig. 1. The component vesicles still go on subdividing, until it assumes the appearance of a single perfect Monadine possessed of two proboscides, eye-spots, &c. By a further developement it constructs for itself an external envelope, which has the appearance of a white ring surrounding the central nucleus.\nWonderful as is the organisation of the last family, it would probably not be more so than that of the Vibriomd\u00e6, was it in our power to display their internal economy in an equally satisfactory manner ; but such is the extreme minuteness of all the members of the family, that even to Ehrenberg this seemed a hopeless wish. The Vibrionid\u00e6 present themselves under the microscope as thread-like bodies of indescribable tenuity, worming their way in countless thousands through the drop of water in which they live, and presenting themselves\n9\nin different shapes, which have been classified as belonging to five distinct genera, named as follows :\u2014The first, Bacterium, contains those forms which exhibit the appearance of stiff-jointed filaments. In the second, Vibrio, the\nFig. 5.\n1, 2, 3. Vibrio subtilis. 4. Vibrio rugula. 5. Vibrio rugula more highly magnified. 6. Closterium monili-ferum. 7. Closterium turgidum.\nd y CL y Q/f three large aggregations of living corpuscles ; x, x, the locomotive papillae ; o, o, openings in the shell.\ncreatures resemble minute chains, which seem to be as soft and flexible as the body of a serpent, although so exceedingly minute that some species have been calculated to be not more than the 300th of a line long, and the 3000th of a line in thickness.\nThe animalcules in some genera assume the appearance of tortuous chains or flexible spiral threads. In Spirillum the body seems rolled into a stiff spiral cylinder, and in Spirodiscus it is arranged in a kind of disc.\nOn examining these little beings while alive, little doubt can be entertained that they belong to the animal series of creation : the manner in which they obviously direct their course at will, and the facility with which all their movements are performed, have caused them to be recognised as animals by all observers. It is, however, to Ehrenberg that we are indebted for the discovery of their real nature. From his observations we learn that these living filaments* minute as they are, are not single animals, but chains composed of numerous associated individuals produced from each other by spontaneous fissure. There even seems to be reason to suspect that their internal structure is in some degree allied to that of the Monadines ; at least in one species, Bacterium triloculare, Ehrenberg perceived a proboscidiform mouth similar to that possessed by the Monadines of Volvox.\nThe peculiar forms assumed by the different genera of Vibrionid\u00e6 seem to depend upon the character of the fissiparous division by which the whole chain is produced, the compound body remaining straight or becoming thrown into spiral folds as the division is equably or unequably carried on.\nThe snake-like movements of the true Vibrios during their progress in the water, Ehrenberg conceived to be produced by a power of contracting forcibly, that resides in the individual","page":9},{"file":"p0010.txt","language":"en","ocr_en":"10\nPOLYGASTRIA.\nsegments of the compound body, which enables them to change their situation relative to each other.\nIn the next family, Closterium, (6, 7, fig. 5,) the locomotive organs present themselves under a very different aspect, as, indeed, do the animalcules themselves. The animalcules are incased in a thin, transparent, shuttle-shaped shell, or mantle, (urceolm,) which is in many species evidently open at both ends. Enclosed in this shell is the exceedingly soft and transparent mucus-like body of the animal, which is frequently entirely full of green-coloured granules and little vesicles. The shell or mantle, when exposed to heat, is reduced to ashes and entirely volatilized, crisping up during the process like horn.\nThe locomotive apparatus is exceedingly singular in its conformation ; it consists of numerous very short, delicate, transparent organs, having the form of conical papillae : these are situated in the neighbourhood of the two openings in the mantle, lying in the inner space, and can be protruded externally to a short distance. It becomes evident, on mixing a few coloured particles with the fluid in which the animal is contained, that these are instruments of locomotion.\nThe family Astasia (1, fig. 6) contains numerous genera remarkable for the contractile power of their bodies, which causes them continually to change their shape, and consequently they become very puzzling objects to the inexperienced microscopist. Many of them are exceedingly beautiful on account of their rich colours ; and so enormously do they abound under certain circumstances, that the water in which they are found is changed to red, green, or yellow, in accordance with the tint of the species which multiplies therein. In many species of this family, contractile proboscides have been found to exist, which most probably form the locomotive apparatus common to the group. Animals very similar to the Astasians, but lori-cated, constitute the family Dinobryina, (6, Jig. 6,) the envelope forming an urceolus, in which the highly contractile body of the animalcule is lodged, having much the appearance of a microscopic Sertularia.\nIn the next family, Amoeba, locomotion is accomplished in a most extraordinary manner, these animals apparently possessing the power of making foot-like processes for themselves, or dispensing with them altogether, just as circumstances render it convenient. The Amoeba, or Proteus, as it was formerly named on account of the facility with which it changes its form, seems to have its body composed of a greyish mucus-like jelly, the shape of which is perpetually changing, sometimes shrinking into a rounded mass, then extending itself in all directions as though it was entirely fluid, or shooting out processes of different kinds from any part of the periphery of its body : its movements indeed seem to be rather fluent than progressive, so easily dees it mould itself to any required form. It is, nevertheless, very voracious, and its shape is frequently found to be modified by the contour and dimensions of\nother animalcules which it may have swallowed. ( 7, 8, 9, 10, 11, 12,13, fig. 6.)\nFig. 6.\n1. Astasia fiavicans. 2. Amblyophys viridis. 3. Euglena acus. 4. Chlorogonium euchlorum, 5. Co-lacium stentorum on a portion of the leg of a monoculus. 6. Dinohryon sertularia. 1, 8, 9, 10, 11, 12, 13. Amoeba dijffluens, exhibiting a few of its changes of form.\nThe genera Difflugia, Arcella, and Cyphidium (1,2, 3, fig. 7) seem to be merely Amoeb\u00e6 endowed with a power of constructing for themselves a carapax or shelly covering of various forms, from the orifices of which the fluent body of the animalcules can be made to protrude, and thus become convertible into instruments of locomotion.\nIn Cyclidium, Pantotrichum, and Ch\u0153to-monas, and their loricated representatives, C/ue-totypla, Ch\u0153toglena, Peridinium, and Gleno-dinium, forming the families Cyclidid\u00e6 and Peridinaeadae, we first find a new system of locomotive organs making their appearance in the shape of vibratile cilia.\nThe locomotive cilia are variously disposed in different genera ; sometimes they are disseminated over the entire surface of the animal, either irregularly or arranged in regular rows ; sometimes they are only partially distributed or are confined to the region of the mouth and anterior part of the body ; but, whatever their situation, their action is similar; they are incessantly in a state of active motion, either propelling the animalcule through the water, or causing currents to flow in definite directions, by the agency of which food is brought to the oral opening.\nFig. 7.\n1. Difflugia oblonga. 2. Arcella. dentata. 3. Cyphidium aureolum.","page":10},{"file":"p0011.txt","language":"en","ocr_en":"POLYGASTRIA.\n11\nThe genus Stentor (fig. 8 ) contains some of the largest and most active animalcules belonging to the class, and, as might be expected, these are amongst the most conspicuous for the perfection of their locomotive organs. These beautiful creatures resemble gelatinous trumpets, the bodies of which are flexible and contractile in all directions, either while swimming about freely in the water, or while attached, as they frequently are, to some foreign body by means of a little sucking disc which terminates the pointed extremity of the tail.\nThe whole of the trumpet-shaped body of Stentor is covered over with innumerable cilia, disposed in regular rows, and of sufficient size to be easily distinguishable by the microscope. Its broad end is terminated by a circular disc, the diameter of which is considerably larger than the widest part of the body. The entire surface of this disc is likewise covered with multitudes of cilia, arranged in regular concentric circles ; and, moreover, its margin is fringed all around with a single row of cilia of larger dimensions, which by the rapid succession of their movements give the appearance of a wheel spinning rapidly round, and by its revolution causing powerful currents in the surrounding water. At the lower part of the margin of the ciliated disc the ciliary zone\nFig. 8.\nturns inwards, forming a spiral fold around a funnel-like aperture (fig. 8) which leads to the mouth, and likewise lodges the orifice through which digested materials are cast out. The currents caused by the marginal fringe around the disc are all directed towards the oral aperture, and consequently, by bringing nutritive particles to the mouth, this part of the apparatus becomes eminently subservient to nutrition. In several species of Stentor, in addition to the apparatus of cilia described above, there is an additional riband-shaped band of these vibratile organs extending from near the mouth to a considerable distance towards the hinder part of the body, the outline of which has an undulated appearance.\nThe Trichodinae, or Urn animalcules, have no pedicle or elongated tail, but are provided with a fasciculus or circlet of cilia situated in front of their bodies, which are disc-shaped, bowl-shaped, or conical, the mouth being apparently a single orifice situated in the ciliary circlet. One species of this group, T. pedicu-lus, seems to be parasitically attached to the Hydra viridis, and allied forms have been met with in the respiratory lamin\u00e6 of several bivalve shell-fish, (Anodonta, Unio, &c.,) and also in Gyrodactylus coronatus, itself a parasite inhabiting the gills of the Crucian Carp (Cy-prinus Carassius). That these animalcules are really Polygastrica, and not sterelminthous en-tozoa. Ehrenberg satisfied himself by feeding them with indigo. Urocentrum seems to be similarly organized, only it is furnished posteriorly with a sharp style-like process.\nBut perhaps the most remarkable as well as most elegant of all the forms of animalcules belonging to this group are the Vorticellce, (fig-9,) the sight of which cannot fail to exact the untiring admiration of the microscopical\nFig. 9.\nStentor Roeselii, highly magnified, t, viscus supposed by Ehrenberg to be the testis.\nVorticella cyathina.\nb, c, d, e, f, exhibit the various steps of fissiparous reproduction in this animalcule.","page":11},{"file":"p0012.txt","language":"en","ocr_en":"12\tPOLYGASTRIA.\nobserver. These beautiful little creatures might be compared to wine-glasses of microscopic dimension, the bells of which are fixed to highly irritable stems, that are attached by their opposite extremity to some foreign body. These stems are endowed with the capability of extending themselves in the shape of straight filaments of exquisite tenuity, and on the slightest alarm or irritation, of shrinking into close spiral folds, so as to draw the little bell as far as possible from danger. The mouth of the bell is fringed with a circlet of cilia, which vibrate rapidly at the pleasure of the animal, causing a magnificent whirlpool in the surrounding water, which brings nutritious substances that may be in the neighbourhood towards the oral orifice, the situation of which is nearly the same as in Stentor, above described, and thus the little being is abundantly supplied with food. The true Vorticell\u00e6, although generally found grouped together in elegant bunches, always have single undivided stems ; but in the genus Carcfiesium, the animals of which are similarly organised, the pedicles sprout from one another so as to have a branched or ramose appearance, while in the genus Epistylis, animals similar to Vor-ticella and Carchesium are met with, the stems of which are quite stiff and inflexible, so much so indeed that the animalcules belonging to this group have obtained the name of \u201c pillar bells \u201d (Saulengl\u00f6ckchen).\nThe family Ophrydinid\u0153 presents us again with very remarkable forms of Polygastric animalcules, allied in structure to the Vorticell\u00e6, but having their bodies inclosed in cases of different kinds, of which it will be necessary to give one or two examples.\nThe genus Ophrydium, (jelly-bell-animalcules,) of which the Ophrydium versatile (fig. 10) is an example, was regarded by the older\nFig. 10.\nSection of a portion of the periphery of Ophrydium versatile, showing the manner in which the individual animalcules are implanted in the mass.\nnaturalists as being a mass of vegetable matter, and had the names of ulva, fucus, conferva, &c. conferred upon it by different authors, until Miiller, in 1786, first announced its real nature and relationship to the vorticelline animalcules. It is found under the shape of a gelatinous mass of a lively or dull green colour, which in consistence may be compared to frog\u2019s spawn, some specimens attaining the size of four or five inches in diameter; the whole forming an irregularly shaped but smooth mass, which is composed of many millions of distinct animalcules, each about jfeth of a line in thickness,\nand about the -^th of a line in length. The space of a square line would therefore contain 9216 of these diminutive beings; a cubic line six times as many, or 55,296; and a cubic inch nearly eight millions, namely, 7,962,624. In the water all these congregated animalcules are disposed in close rows, something in the same manner as in Volvox. On shaking the mass many others show themselves within between the former, so as to form from three to five different ranks. At first all the gelatinous cells appear to be connected with the centre of the mass by filamentary prolongations, but these disappear as they proceed internally, so that the middle seems to be hollow and full of water; the whole, indeed, might be compared to the gelatinous polyp masses (Alcyonid\u00e6) found upon the sea-shore, only the structure of the animalcules is polygastric and not that of polyps.\nIn the other genera belonging to the family Ophrydinid\u00e6, namely, Tintinnus, Vaginicola (9, fig. 11,) and Cothurnia, although living in gelatinous transparent sheaths, and resembling Vorticell\u00e6 in their structure, are not associated in masses, but remain permanently detached and solitary.\nThe family Encheliad\u00e6 contains various forms of animalcules, having the oral and anal orifices distinct and situated at the opposite extremities of the body. The different genera of which it is composed may be distinguished as follows :\u2014\nEnchelis, (revolving animalcule,) has its body flask-shaped, (,\\,fig> 11,) without any cilia externally, but with a circlet around the mouth, which is suddenly truncated and destitute of any dental armature.\nDisoma, (double-bodied animalcule,) creatures nearly resembling Enchelis in form and structure, but with a double body (6,7,fig. 11).\nAct inop hrys, (sun animalcule,) having the exterior of the body unprovided with locomotive cilia, but stuck over with setaceous ten-tacula which radiate in all directions.\nTrichodiscus, (radiated disc animalcule,) resembling Actinophrys, only the body is here\nFig. 11.\n1, 2, 3, 4, 5. Enchelis farcimen, swallowing food. 6, 7. Disoma vacillans. 8. Lachrymaria proteus, 9. Vaginicola decumbens.","page":12},{"file":"p0013.txt","language":"en","ocr_en":"POLYGASTRIA.\n13\ncompressed, and only furnished with a single row of setaceous tentacula, situated around its margin.\nPodophyra, (radiated foot animalcule,) is an Actinophrys with a spherical body, from which projects a long straight pedicle, which, however, is not attached to any foreign body.\nTrichoda, (hair animalcule,) an Enchelis having its mouth obliquely truncated and furnished with a lip; its body is unprovided with a neck-like prolongation.\nLachrymaria, (lachrymatory animalcule,) (8, fig. 11,) an Enchelis having its body destitute of cilia externally, but terminated by a long thin neck, which is clavate at the extremity, and ends with a mouth provided with a lip and ciliated margin.\nLeucophrys, (ciliated animalcule,) an Enchelis, with its body entirely covered with vibratile cilia\u2014its mouth is obliquely terminal and provided with a kind of lip, but without dental organs. (1, fig. 12.)\nHolophrya, (woolly animalcule,) an Enchelis having the exterior of its body entirely ciliated.\nProrodon (toothed rolling animalcule). In this genus, like the last, the body is covered all over with vibratile cilia, and the mouth\nFig. 12.\n1. Leucophrys patula. 2. Prorodon teres. 6, mouth ; c, outlet of alimenta^ tube.\ntruncated, but the latter is remarkable for being armed with a circlet of teeth of a very peculiar structure situated within its margin. (2, fig. 12.)\nThe family Colepinidae consists of but one genus, Coleps (1, 2, fig. 13), the animalcules belonging to which have all the characters of Enchelis, except that they are loricated. These animalcules are found among confervse, more especially in summer time. As long as they are swimming it is difficult to perceive the transparent case in which they are enclosed ; but if they are allowed to get dry or are crushed between two plates of glass, its presence becomes manifest as well as its brittleness. In shape this external covering resembles a little barrel made up of rows of plates or rings, between which the cilia seem to be exserted (testula multipartita). Anteriorly it is truncated, its margin being either smooth or toothed,\nand posteriorly terminates in three or five little sharp points.\nThe next family, Trachelinid\u00e6, contains all those non-loricated animalcules whose alimentary canal has two distinct orifices, but of which one only, the anal, is terminal. The genera that belong to it are very interesting objects, and many of them of great beauty. The reader\nFig. 13.\n1, 2, Coleps hirtus. 3, 4. Trachelius anas. 5. Trachelitis ovum.\n6, mouth ; a, outlet of alimentary canal.\nwill be able readily to recognise them by the following characters :\u2014-\nTrachelius (neck animalcules, 5, fig. 13). These may be readily known by their excessively elongated upper lip, which has the appearance of a long proboscis, or rather, perhaps, resembles the neck of a goose or swan, from which circumstance some species ( Trachelius anas) have received their best known appellations. Attentive examination, however, shews that the mouth is situated at the bottom of this neck-like prolongation (3, 4, fig. 13), and not at its extremity, as was the case in Lachrymaria. The body is ciliated over its entire surface; nevertheless the movement of some species is very sluggish, locomotion seeming rather to be effected by creeping and bending the body than by the exertion of the cilia. Some species are exceedingly voracious, as for example Trachelius vorax, figured by Ehrenberg, which is represented in the act of swallowing a Loxodes Bursaria, of which six may be seen already lodged in the interior of its body.\nLoxodes (lip animalcules). These have not the neck-like appendage of the last genus, but have the upper lip dilated and hatchet-shaped.\nBursaria (purse animalcules). In these the mouth is very wide and placed laterally, with very capacious prominent lips, but without any dental structure. They are veiy voracious, and although generally met with in water, some species, viz. B. Fntozoon, B. intestinalis, and B. cordiformis, live parasitically in the intestines of the frog, toad, and water-newt.\nThe genera Spirostomum (snail animalcules), Phialina (spigot animalcules ), Glaucoma (pearl animalcules), are too nearly allied to the preceding to render any special account of them necessary.","page":13},{"file":"p0014.txt","language":"en","ocr_en":"POLYGASTRIA.\nThe genus Chilodon presents a very similar organisation, but is remarkable from the circumstance that its mouth is furnished with a tubular fasciculus of setaceous teeth, while the anterior part of its body is advanced forward in the shape of an expanded membrane or prolonged on one side, so as to form an auriculated appendage. In Nassula, likewise, a similar dental structure exists, but this will be best described hereafter.\nNutritive system.\u2014By employing coloured organic substances as food for these animalcules, Ehrenberg at length succeeded in developing the organisation of the nutritive apparatus in these microscopic beings. For this purpose he made use of pure indigo, carmine, sap-green, and other vegetable colouring substances which are insoluble in but miscible with water, very finely levigated, and which the animalcules readily swallow, so that in a few minutes the coloured particles are distinctly visible in the interior of their transparent bodies.\nFrom observations conducted in this manner the following results were obtained :\u20141st. That there is no absorption of the coloured fluid through the general integument of the bodies of infusorial animalcules, although this was formerly supposed to be the only manner in which they could be nourished ; but, on the contrary, that they were all furnished with a special mouth and internal nutritive apparatus.\n2nd. That the smallest species of Infusoria which can be observed with our instruments, even those not more than of a line in length, have an internal set of nutritive organs as well as the largest, so that in the Monads even four, six, or eight sacculi are visible in the interior of the body, which are obviously filled through an oral aperture.\nIn the genera Enchelis, Paramecium, and Kolpoda, moreover, an intestiniform tube was discovered traversing the whole length of the body, and opening by a distinct anal orifice. To this central canal are appended numerous blind vesicles, giving the whole apparatus the appearance of a bunch of grapes. In Paramecium aurelia and Paramecium chrysalis Ehrenberg counted from one to two hundred of these vesicles, which became filled with blue, red, or green, according to the colouring matter employed.\nWe have, however, already, in the preceding pages, described the different arrangement of the alimentary canal in the various forms of polygastric animalcules, so that few further observations are necessary in this place. Whoever wishes to observe these little beings swallow coloured food, and thus witness the filling of the nutritive sacculi, must, in order to avoid disappointment, carefully observe that the materials he employs are perfectly pure, the indigo, carmine, and sap green sold in the shops being generally so inuch adulterated that the animalcules refuse to swallow it ; secondly, that it be reduced by l\u00e9vigation to the most extreme state of division\u2014 grinding it for a length of time with water on a slab, with a muller, is the best way to accomplish this. When thus prepared, by placing\na little with a camel\u2019s hair brush in the drop of water which contains the animalcules, but very few minutes are required with some species to exhibit numerous vesicles filled with the coloured substance. When filled, Ehrenberg has observed that sometimes one of them will in a short time empty itself, and its contents be suddenly transferred to another, whereby it seems as if the vesicle itself had a power of voluntary locomotion, which it has not. But however easy it may be thus to fill the stomachal vesicles, it is by no means so easy a matter to detect the central canal to which they are appended, insomuch that the generality of observers are quite unable to detect its presence. Upon this point Ehrenberg remarks, in reply to those who have doubted its existence, that there are only some animalcules in which it is possible to see it clearly ; and it is therefore necessary to seek out such species in order to obtain a view of it. In many it is of all things most difficult to see it ; but the cause of this does not lie in its absence, but in the nature of the functions it has to perform, for this canal, like the oesophagus of larger animals, only serves for the transmission of food, not for its retention and digestion. It becomes dilated while food is passing through it, at will, like the mouth and oesophagus of a snake when it swallows a rabbit, and immediately collapses again, and becomes quite invisible when not actually in use.\nProvided the indigo and carmine employed for the purpose have been sufficiently levigated, nothing is easier than to demonstrate the presence of the stomachal vesicles; but to exhibit the central canal, and the tubes that communicate between it and the gastric sacculi, is a much more difficult task, and can only be done under very favourable circumstances. We were, indeed, long sceptical concerning their existence; but after examining Professor Ehrenberg\u2019s preparations of these structures, we were ultimately convinced of the accuracy of his views concerning them.\nWhoever wishes to see the intestinal tract distinctly must examine it in large specimens of some of the following species, most of which are sufficiently common :\u2014Chelodon cu-cullulus, Trachelius ovum, Epistylis plicatilis, Vorticella chlorostigma, Vorticella convallaria, Opercularia articulata, or Stylonychia mytilus. On putting a little indigo into the water with some of these, it may be readily seen to enter their large mouths, and pass into their stomachs, from which it is again speedily ejected.\nIn the Monads and allied families the alimentary apparatus consists of several distinct cells, from eight to twenty in number, but which are not all of them filled at the same time. When contracted they are quite invisible; yet sometimes, when filled with a clear fluid, they are to be distinguished under the form of minute transparent vesicles in the interior of the animalcule. The mouth may sometimes be easily perceived under the form of a clear transparent spot, situated at the base of the proboscis, to and from which streams of water may be seen to proceed, bringing","page":14},{"file":"p0015.txt","language":"en","ocr_en":"POLYGASTRIA.\n15\nwith them the materials for nourishment (fig. 14). In the interior of the body the nutritive sacculi appear like so many little empty bags hanging from the mouth. The food of the Monads seems to consist entirely of particles of decaying matter.\nTig. 14.\nMonas quttula, highly magnified, showing the direction of the nutritive currents.\nDental system.\u2014A very remarkable dental apparatus was discovered by Ehrenberg to exist in some of these diminutive beings, their presence being recognised in several different species, viz. Euodon cucullus (Synonyme, Kol-poda, Loxodes cucullus), Nassula ornata, Nas-sula elegans, Nassula aurea, Prorodon niveus, Prorodon compressas, and others. Both in their form and connexions these teeth are very remarkable, presenting the appearance of a long slender cylinder or hollow cone, situated at the entrance of the mouth, around which they form a closely approximated series (fig. 15). These teeth\nDental apparatus of Chilodon ornatus. (After Ehrenberg.)\nare composed of a hard substance ; for when the soft parts of the animalcule are crushed between two plates of glass, they still remain distinctly visible, proving that they are of a denser texture than the rest of the body. Their number varies in different genera from sixteen to thirty, the former being the minimum and the latter the maximum yet observed. In animalcules thus provided with a dental apparatus the pharynx seems to have little to do with the act of nutrition ; indeed it frequently happens that while the little creature vibrates its cilia to produce the currents that bring it food, its mouth is kept open and motionless, so that the materials that serve for its nourishment pass through it unobstructed : but when larger morsels are to be swallowed, they are\nfirst seized and bruised by the dental apparatus. In this case the buccal cylinder first of all expands in front to receive the morsel; it is then narrow posteriorly: but as the aliment passes onward it becomes contracted in front and dilates behind, so as to push the food towards the mouth. Sometimes, however, these movements can be witnessed without any large morsels of food being present in the dental cylinder. While the mouth is kept open, Monads and other animalcules may frequently be seen to enter it with facility as far as the intestine ; in which case the contraction of the dental circlet seems to serve to prevent its return back again, should it try to escape in this direction.\nA very remarkable circumstance observable in these teeth is the rapid manner in which new sets are formed as often as the fissiparous habits of the animalcules render their reproduction necessary. *This regeneration of whole sets of teeth, a phenomenon so unusual among other races of animals, is among these Infusoria a matter of every day occurrence, a new set being produced whenever spontaneous division occurs: nay, should the animalcule be mutilated so that only the hinder half of its body remains, we are assured by Ehrenberg that the missing portions will soon be reproduced, provided with a new mouth and circle of teeth exactly similar to their predecessors; and when they spontaneously divide by transverse fissure, a process which occupies but a short space of time, the hinder portion, when separated, is found to be provided with a mouth and set of teeth completely organised in every respect (1, fig- 16). Sometimes, indeed, they may be observed during this separation of the adult animal into two young ones, and the progress of the developement of the wanting parts absolutely witnessed. Under such circumstances Ehrenberg states, that such is the rapidity of the process that the division of the body, and the formation of a set of twenty new teeth, may easily be accomplished in the space of a couple of hours.\nFig. 16.\n1. Nassula ornata, in progress of fissure. 2. Amphi-leptus fasciola. 3. Trachelocerca viridis. 4. Tra~ chelocerca biceps. (After Ehrenberg.)\nMuscular system.\u2014In the generality of those","page":15},{"file":"p0016.txt","language":"en","ocr_en":"16\nPOLYGASTRTA.\nacrite animalcules it is almost needless to say that no muscular fibres are obvious, although their bodies are capable of various contortions, and some of their movements under the microscope are extremely brisk and active. Nevertheless, in some of the Vorticellin\u00e6, (Vorticella, Stentor, Carchesium, Opercularia,) Ehrenberg considers that their presence has been detected, and has even assigned their direction, some being, as he asserts, longitudinal and others transverse. In the stems or pedicles of Carchesium and Tintinnus this appearance of muscular fibre is more especially evident ; and when we consider the highly organised condition of the genera in question, there seems to be no physiological reason for considering their existence improbable.\nNervous system and organs of sense.\u2014No nervous fibrils have as yet been discovered in any polygastric animalcule, and, in accordance with this acrite condition,*no special instruments of sensation could, according to all physiological analogy, be expected to exist; nevertheless, in many genera the existence of one or two minute spots of a brilliant red colour is conspicuous, which are invariably found to occupy the same position in a given species possessed of them. These red spots are generally pronounced to be eyes, although for what reason, except that they correspond in colour with the acknowledged eyes of some of the lowest forms of the Articulata, it is difficult to conjecture. In two species indeed, (Euglena longicauda and Amblyophys,) Ehrenberg says he saw a \u201c clear sharply defined ganglion,\u2019' (einen hellen, scharf umgrenzten Markknoten,) under the red eye-spot, without, however, offering the slightest proof that the \u201c clear sharply defined body \u201d in question was composed of nervous matter. Should, however, Ehrenberg\u2019s surmises, (for these assertions are nothing more,) be correct, we should ipdeed encounter in the Infusoria an apparatus of vision of the simplest possible description, consisting merely of a brain and a coat of coloured pigment, thus dispensing both with the refracting media that usually constitute an eye, and the nervous communication generally found between it and the brain. Be this as it may, the Polygastria are evidently possessed of considerable perceptive power, (those without red spots quite as much so as those provided with them ;) however rapid their movements, they can steer their course with accuracy, and avoid impinging against each other ; they can likewise perceive the slightest contact, and some species, such as the Vorticellin\u00e6 for example, exhibit a most exquisite sensibility of touch.\nSecretions. \u2014 Several species of Polygastria secrete a peculiar fluid of a beautiful violet colour, which is poured into the intestinal canal, where it colours the excrements with which it is expelled from the body. In Nas-sula ornata, (l, fig. 16,) the apparatus for secreting this fluid is situated at the anterior part of the body, where it is recognisable as an irregular square spot of a violet colour, situated upon the dorsal surface of the body immedi-\nately opposite to the dental cylinder. This spot is composed of a great number of little violet globules of unequal size, or, to speak more correctly, of an aggregation of colourless vesicles filled with a violet-coloured fluid. From this spot a canal may be traced running along the back, resembling a string of pearls, in which the violet secretion is conveyed towards the posterior part of the body. It is only in the posterior third of the body that there seems to exist a direct union between this canal and the alimentary apparatus, for at this point the violet colour of the secretion becomes altered and mixed with foreign matter. In all these Infusoria the violet secretion is expelled through the anal orifice situated at the hinder part of the body, either by itself or in conjunction with the excrements. The aggregation of vesicles situated in the back of the neck seems to be the secreting organ of this remarkable fluid, seeing that no vessels could, be detected in communication with it, and. the surrounding parts were quite transparent and colourless. Ehrenberg believes that the violet liquid, which is of a slightly viscid or almost oily character, possesses some dissolving power, for he has noticed in the alimentary canal of animalcules which contained a large proportion of it, that fragments of oscillatori\u00e6 and other substances taken as food were always discoloured, divided, or decomposed apparently by its action.\nReproduction.\u2014 Not the least remarkable feature in the history of the Polygastria is their extraordinary fecundity, which indeed far exceeds that of any other class of animals. The infusorial animalcules, constituting as they do the basis of the great pyramid of the animal creation, the living pasturage diffused through the waters of our globe, on which innumerable creatures have to feed, must be multiplied in proportion jto the vast demand for food of this description; and, accordingly, their multiplication is effected in various ways, all of which are so prolific that it becomes no longer a matter of astonishment that they swarm to such an extent in every drop of stagnant water, or that their exuvi\u00e6 are found in many localities accumulated in such abundance, that strata of soil and even vast rocks seem to be entirely composed of their remains.\nFissiparous generation.\u2014This mode of reproduction consists in the spontaneous fissure of the original animalcule into two or more divisions, each of which soon becomes complete in all its parts, and again divides in a similar manner. The different steps of this process, which may easily be witnessed, are in ordinary cases as follows. The body of the parent is seen, on its arrival at maturity, to become intersected by a transparent line, which divides it into two equal halves. In a short time this transparent line becomes indented at each extremity, and, as the indentations become more pronounced, the original creature becomes evidently converted into two, which are united together by a kind of isthmus, (figs. 17 & 18 ) and at length, ihe isthmus becoming continually more and more attenuated, the slightest","page":16},{"file":"p0017.txt","language":"en","ocr_en":"POLYGASTRIA.\t17\neffort, or the mere action of the vibratile cilia completes the operation, and the two young animalcules, thus formed, part company and commence an independent existence.\nThe direction of the line of separation varies in different species, and even in individuals of the same species ( fig. 17. 4, 5, 6, 7, 8) ; sometimes it is transverse, sometimes oblique, and in other cases it traverses the long axis of the body, where the form of the animalcule is elongated or oval. This method of reproduction is exceedingly prolific ; for, as each successive generation arrives at maturity in the course of a few hours, and undergoes the same process of division, it will be found on computation that the progeny derived from a single animalcule may, in the course of a single month, amount to many hundred millions in number.\nIn the Vorticellae and allied forms supported by rigid or flexible pedicles the fissiparous process is essentially similar. The adult bell {fig. 9, a) preparatory to its division becomes considerably extended in a lateral direction (b), in which condition the line of fissure is indicated, extending from the mouth of the bell to the point of its connection with the pedicle. An indentation soon appears which, progressively extending downwards, soon separates the original animalcule into two, both of which are attached to the stem {c, d). In a short time one or both break loose ; in the former case the stem survives, in the latter it perishes. The detached bells speedily assume a new form (e,f), and might easily be mistaken for a totally different genus swimming about by means of cilia situated at both extremities of their barrel-like bodies. At last, having found a fit support, they fix themselves to it, the attached extremity becoming gradually elongated into a delicate irritable filament similar to that which they possessed prior to the commencement of the fissiparous process.\nGemmiparous reproduction. \u2014 Besides the above mode of increase, many of the Vorti-cell\u00e6 and similarly organized forms throw out little gemmae or lateral buds in the same manner as the Hydrae and some other Polypes, which, as they advance to maturity, assume the form of the parent stock, from which they at length become detached, or else remain associated with the original from whence they sprung.\nSporiferous reproduction. \u2014 The gastric vesicles of the Polygastria occupy but a small proportion of the interior of their minute bodies ; the rest is partially filled up with a granular tissue, which seems made up of nucleated cells, or, in other words, of sporules or spawn, the germs of future progeny ready to be called into active existence when liberated from the nidus in which they were generated. In Kolpoda' cucullus {fig. 18, 3), these sporules are represented in the act of becoming discharged from the parent animalcul\u00e6.\nIn many species of animalcules it is easy, with the assistance of a good glass, to perceive in the interior of their bodies certain isolated sacculi endowed with very remarkable powers of contraction and of dilatation ; this\nVOL. IV.\nis repeated at regular intervals ; and so great is the contractile force that the little sac seems entirely to disappear, and then in a short time slowly dilating regains its former size. These sacculi Ehrenberg at first thought to be stomachal cavities, which the creature could alternately fill ahd empty ; but subsequent observations convinced him that they were organs of a peculiar character. By slightly compressing large specimens, such as Paramecium aurelia, he further observed that these contractile vesicles were generally two (sometimes three) in number, occupying determinate situations in the creature\u2019s body, and that from each of these a number (eight) of little canals were given off like rays from a centre towards the circumference of the body. These canals became gradually enlarged as the sacculus contracted ; and vice versa, when the vesicle dilated the canals shrunk and disappeared. Each canal is slightly enlarged at its origin from the central cavity, and the whole apparatus has the appearance of two little Qphiuri, or thin-rayed starfishes, enclosed in the body of the animalcule {fig- 18, 1 & 4, s, s). The contractile sacculi were seen by Ehrenberg in at least four-and-twenty different species of Polygastrica ; but the radiating canals were detected in two only, viz. Paramecium and Ophryoglena,\nFig. 17.\n1,2. Spirostomum virens. 3. Glaucoma scintillons. 4, 5, 6, 7, 8. Glaucoma scintillons in progress of fissiparous reproduction, showing its different modes of fissure. (After Ehrenberg.')\nThese organs exhibit, both in their number and situation, important differences in different species. In Paramecium aurelia, Paramecium caudatum, Leucophrys sanguinea, Trachelius anas, Bursaria vernalis, and Stentor Mullen, two of them are found, one situated in the middle of the anterior, and the other in the middle of the posterior, halves of the animal. All the above species, with the exception of Stentor, multiply by spontaneous transverse division, and when thus divided each portion retains one of the contractile organs, and their being thus double seems to haye some relation\nc","page":17},{"file":"p0018.txt","language":"en","ocr_en":"18\nPOLYPIFERA.\nwith the kind of fissiparous division which the animalcules undergo. At certain periods four of these sacculi are met with in several of these Infusoria, whilst at others only two are found in animalcules of the same species. When four are present, there are always two situated in each half of the body, and it is remarkable\nFig. 18.\n1 & 4. Paramecium aurelia. 2, 3. Kolpoda cucullus. 8, s, contractile vesicles ; t, testes ; o, oral opening ; a, anal opening. (After Ehrenberg.)\nthat all the Infusoria thus furnished are susceptible both of transverse and longitudinal division, so that when so divided each quarter retains one of these organs. In Euodon cucul-lulus three of these vesicles are present, two of which are placed one on each side of the dental cylinder, and the third in the hinder part of the body near a dilatation of the alimentary canal in the vicinity of the anal opening. This animalcule likewise divides both longitudinally and transversely.\nThere is another organ regarded by Ehrenberg as playing an important part in the organization of these Infusoria. This is of a roundish\nFig. 19.\nEuplotes Charon, exhibiting its different modes of fissiparous generation. (After Ehrenberg.)\nform, but less transparent than the contractile sacculus in the neighbourhood of which it is situated, but its presence has only been detected in four or five species. With respect to the functions to be ascribed to the parts above\ndescribed, it is by no means easy to come to any satisfactory conclusion. Ehrenberg considers that the contractile organs provided with their radiating canals cannot be regarded as hearts because their movements are so slow ; neither can he regard them as respiratory organs, which would require the presence of a vascular apparatus more distinctly developed than it appears to be in the Polygastric animalcules ; he is, therefore, disposed to believe them to be connected with the generative system, and refers to them the office of fecundating the ova contained in the interior of the body by dispersing the seminal fluid.\nThe opaque body above, described, the same authority suggests to be the testis, believing it to secrete a seminal fluid. Both these suppositions are based upon a fancied analogy between the parts in question and certain organs which are met with in the Rotifera, and it is needless to say that they are at present purely hypothetical.\t(T. Rymer Jones.)\nPOLYPIFERA. \u2014 A class of Zoophytes most extensively distributed over the surface of the globe, inhabitants both of the ocean and of fresh water, and important both on account of their numbers and of the magnitude of the structures raised by their agency. The most obvious character common to this vast race of animals is, that their mouths are surrounded by radiating tentacula, arranged somewhat like the rays of a flower ; and hence the terms Zoophyta, Phytozoa, and An-thozoa, have been more especially applied by naturalists to the members of this group of living beings. So plant-like, indeed, are the forms of many genera, that the ancients regarded all the stony polypes as stony vegetables, or as vegetating stones, and invented many theories to explain .their growth. The earlier modern naturalists thought them plants, and even Tournefort has described twenty-eight species in his \u201c Institutions of Botany but he was the last naturalist who committed this grave error. The animal nature of the Polypes was suspected by Imperato in 1669, *was proved byPeyssonel in 1727, and shortly afterwards confirmed by Reaumur and Jussieu, the latter of whom, in 1741, added them to the animal kingdom.* In order to facilitate our investigations concerning the anatomy and physiology of so extensive a series of organized beings, it becomes imperative that we should first divide them into groups, composed of such genera as are most nearly allied by their structure and general habits, each of which will in turn require our separate notice.\nClass. POLYPIFERA.\nSub-class 1. Hydrozoa.\nBody gelatinous, free, naked, presenting internally a simple stomachal cavity, which is provided at its entrance with highly contrac-\n* See the History of Zoophytology in Dr. Johnston\u2019s admirable \u201c History of the British Zoophytes.\u201d Lond. 1847.","page":18},{"file":"p0019.txt","language":"en","ocr_en":"POLYPIFERA.\t19\ntile tentacular cirrhi ; without traces of viscera, and reproduced by external gemmae.\nHydra {fig. 25).\nSub-class 2. Anthozoa.\nMouth of polype flower-like, surrounded by contractile tentacula, the margins of which are\nFig. 20.\nPolypes of Cydonium protruded, magnified. {After Muller.')* g\na, with the tentacles expanded ; b, tentacles closed.\nfringed, but destitute of vibratile cilia ; stomach forming a distinct bag, without any intestinal canal ; ovaria conspicuous, lodged in the interior of the body, beneath the stomachal cavity.\nFamily 1. \u2014 Alcyonid\u00e6. Polypes distributed over the surface of a common mass, which is polymorphous, irregular, fleshy, adherent, and composed of a suberiform substance supported by calcareous aciculi, Alcyonium, Lobularia, Cydonium.\nFig. 21.\nCydonium Mulleri. {After Muller.) *\nFamily 2. \u2014 Corallid\u00e6. Polypes irregularly scattered, and more or less prominent upon the surface of a polype tree or common stem, which is arborescent, fixed by a basement, and composed of a solid, horny or calcareous axis enveloped by a sort of gelatino-calcareous living cortex.\nCorallium, Isis, Gorgonia, Antipathes.\nFamily 3. \u2014 Madreporid\u00e6. Polypes inhabiting cells distributed over the surface of a stony polypary, which is fixed, and generally arborescent. The cells are small, sub-lamel-lated, and constantly porous in the intervals and in their walls {fig. 22).\n* Zool. Dan. tab. lxxxi. figs. 3 & 4.\nDentipora, Astr\u00e6opora, Sideropora, Stylo-pora, Coscinopora, Gemmipora, Monti-pora, Palmipora, Heliopora, Alveopora, Goniopora, Porites, Seriatopora, Pocillo-pora, &c.\nFig. 22.\nA\tB\nA, \u201c Madrepore abrotanoide ; \u201d b, a portion magnified. {After Quoy et Gaimard.)\nFamily 4. \u2014 Madrephyllid\u00e6. Animals simple or aggregated (in the latter case more or less deformed by their connection with those around them), and containing in their substance a great quantity of calcareous matter, forming a stony polypary, which is either free or fixed, and having a laminated surface, or provided with laminated cells.\nCyclolites, Montlivaltia, Fungia {figs. 38, 39), Polyphyllia, Anthophyllium, Turbi-nolia {fig. 41), Turbinolopsis, Caryo-phyllia {fig. 42), Sarcinula, Columnaria, Stylina, Catenopora, Seringopora, Den-drophyllia, Lobophyllia {fig. 23), Mean-drina {fig. 40), Dictuophyllia, Agaricia, Tridacophyllia, Monticularis, Pavonia, Astr\u00e6a {fig. 43), Echinastr\u00e6a, Oculina, Branchastr\u00e6a, &c.\nFig. 23.\nLobophyllia angulosa. {After Quoy et Gaimard.)\nFamily 5. \u2014 Zoanthid\u00e6. Polypes more or less approximated, sometimes soldered to-gether, encrusted, or solidified by foreign\nc 2","page":19},{"file":"p0020.txt","language":"en","ocr_en":"20\tPOLYPIFERA.\nbodies, and forming, when dried, a sort of coriaceous polypary.\nZoanthus, Mamillifera, Corticifera.\nFig. 24.\nActinia sociata (Ellis'). Zoanthus (Cuvier). (After Ellis.)\nFamily 6. \u2014 Actiniad\u00e6. Body soft and fleshy, free, mouth furnished with several rows of simple or branched tentacula.\nActinia {fig. 45) Lucernaria, Moschata, Ac-tinecta, Discosoma, Actinodendron, Me-tridium, Thallasianthus, Actineria, Acti-noloba, Actinocereus, &c.\nFamily 7.\u2014 Pennatulid\u00e6. Animals po-lypiform, with eight pinnated tentacles, more or less prominent, and regularly arranged upon a part only of a common polypary, which is free or adherent. Its form is determinate, and it is composed of a central axis, which* is solid, and enveloped in a fleshy cortex, often of considerable thickness, and supported by calcareous aciculi.\nPennatula {fig, 44), Renifla, Virgularia, Scirpearia, Pavoniaria, Veretillum, Om-bellularia.\nSub-class 3, Aulozoa* (nobis). (Tubular Polypes.)\nAnimals simple or compound, occupying the interior of corneous or calcareous tubes, which are either simple or ramified ; polypes terminal or lodged in lateral cells ; reproduction multiform.\nFamily 1. \u2014 Tubularid\u00e6. Animals generally aggregated ; polypes terminal, not retractile ; l'eproduction by ova produced near the bases of the tentacula, and unenclosed in any cell ; polypary pergamentaceous or corneous, simple, tortuous, or regularly ramified ; sometimes wanting; tentacula, numerous, solid.\nTubularia {fig. 48.), Endendrum, Pennaria, Syncoryna {fig. 47), Coryna, Hydractinia, Stipula.\nFamily 2.\u2014Tubiporid\u00e6. Polypary composed of calcareous tubes, arranged in successive stages like the pipes in an organ ; polypes terminal, with eight pinnate arms.\nTubipora {fig. 52),\nFamily 3. \u2014 Sertularid\u00e6. Polypes hy-driform, provided with simple tentacula, which are never ciliated ; lodged in lateral cells of various shapes and disposition, continued into the interior of the tubular polypary, which is ramified, horny, subarticulated, and fixed by a root-like basis.\nSertularia (fig. 55), Campanularia.\n* a\u00f9xk, a pipe or reed ; animal.\nSub-class 4.\u2014Brvozoa (Ehrenberg).\nCiliobrachiata (Farre).\nAnimals polypiform, with the tentacula around the mouth covered with vibratile cilia, by the agency of which food is furnished to the oral opening ; alimentary canal complete, being furnished with an intestine and distinct anal orifice ; body generally enclosed in a corneous or calcareous cell ; with or without an operculum.\nEschara (fig. 57), Flustr\u00e6, Bowerbankia (fig. 56), Pedicellina (fig. 65), Lagunculus (fig. 61), Cristatella Mucedo.\nPolyps are invariably aquatic animals, some inhabiting fresh water, but the great body are marine, and most numerous in tropical seas. In very high latitudes only Cellarians, Sertula-rians, and Alcyons occur : and in the vicinity of volcanic islands in the polar seas Corallines and Gorgonians. These latter multiply a little from 6\u00b0 to 9\u00b0 N. Lat., and as they approach the tropics attain their full powers of growth and multiplication. Some frequent the mouths of rivers where there is a conflux of fresh and salt water; some love atmospheric influence, while others avoid it. The marine ones frequently plant themselves on rocks in different aspects, often regulated by the climate. They rarely expose themselves to violent currents, or the direct shock of the waves, being generally found in the hollows of rocks and submarine caverns, and in gulfs, where the water is less agitated.\nHYDROZOA.\nThe Hydr\u00e6 are to be met with abundantly in summer time in almost every pond or ditch, and may easily be collected along with the duck-weed or other aquatic plants among which they reside. On filling a glass jar with the water in which they reside, and allowing it to stand for a few hours undisturbed, the little polypes will be found, sometimes in great numbers, adhering to the sides of the vessel, in which position nothing is easier than to watch their proceedings, and with the assistance of a simple magnifier to verify the descriptions which Trembley and others have given of the extraordinary phenomena they exhibit.\nThe Hydra viridis, or short-armed polype, which is the species most commonly met with in this country, resembles, when expanded, a little bit of green sewing-silk, about the sixth part of an inch in length, attached by one extremity to the interior of the jar, or to any other fixed body, and having the opposite end slightly untwisted,\nWhen moderately magnified, the body of the animal is found to be a little bag open at one extremity, the opening, which is in fact its mouth, being surrounded with seven delicate filamentary tentacula ; while the other end is provided with a little flattened disc or sucker, by which it fixes itself to any foreign body (fig. 25). Its substance seems to be entirely composed of a gelatinous material, in which are contained numerous greenish granular particles suspended in a glairy","page":20},{"file":"p0021.txt","language":"en","ocr_en":"POLYPIFERA.\t21\nfluid ; and, to an ordinary observer, no fibres of any kind are distinguishable in any part of\nFig. 25.\nHydr\u00e6 virides in different \u2019stages of extension and contraction, reproducing gemmiparously, attached to the roots of duck-weed. (From Roesel.')\nits body : nevertheless it is highly contractile, shrinking, when disturbed, into an almost invisible jelly-like speck, and again slowly expanding itself when left quiet. Incapable as such a creature would appear to be of any active exertion, this little gelatinous bag is soon found to be gifted with a capability of locomotion, which is exercised in the following manner : whilst attached to the side of the glass by the sucker at its closed extremity, which forms a minute foot, something like that of a Gasteropod Mollusk, the little polype gradually inflects its body until some of the tentacula around its mouth are brought in contact with the supporting surface, of which they take a firm hold ; in this position it detaches its posterior sucker, and, advancing it towards its head, again fixes it, and thus progresses, after the manner of a leech, by a repetition of the same man\u0153uvres. It may, however, be easily imagined that, owing to the minute size of the Hydra, and the extreme slowness of its contraction, this mode of progression is by no means remarkable for its speed, and in fact a march of an inch will occupy it many hours in its performance ; accordingly the polype has been endowed with another mode of transit, of which it can avail itself at pleasure. Although its body is specifically heavier than water, so that when detached from its hold it sinks helplessly to the bottom, it is able, when occasion requires, to row itself about in a very ingenious manner. In order to accomplish this feat, it first creeps to the top of the water, and protruding its sucker to a little distance above the surface, hollows. it out into a saucer-like cavity, the buoyancy of which is sufficient %to keep it afloat ; and then, supported by this curiously-contrived boat, the little Hydra rows itself about by means of its tentacula in whatever direction it chooses. No traces of nervous matter are perceptible in the composition of the Hydra, which, in its whole structure, is\ncompletely acrite ; nevertheless it is evidently able to appreciate the presence or absence of light ; for if a number of these little animals are confined in a glass vessel, one side of which is exposed to light while the other is kept in the shade, they are always found to congregate on the illuminated side, and by turning the glass round it will be found that by changing their position, they will endeavour to regain a situation exposed to the solar influences : seeing, therefore, that they are absolutely destitute of eyes, it would seem that they perceive light by the sense of touch alone.\nIt might naturally be supposed that a creature so low in the scale of organization would be compelled to subsist upon the simplest possible aliment, yet, strange to say, this little polype is carnivorous in its propensities, and is moreover gifted with such terrible powers of destruction, that animals far larger, stronger, and more active than itself fall a prey to its voracity : the Entomostracous Crustaceans, the larv\u00e6 of insects, and minute Annelidans, constitute its ordinary diet, and vainly endeavour to escape from its clutches. Whilst watching for prey, the Hydra remains perfectly at rest, suspended by its tail, and keeping its oral tentacula widely spread out in different directions, nor has it generaljy to wait long before some of the multitudinous animals that crowd the water in its vicinity impinge against its outspread lines, when immediately, as if the wand of an enchanter had been laid upon it, the career of its victim is arrested; though apparently only touched, not seized, it immediately sinks motionless as though paralysed by the contact, and only after some time recovers its former vivacity. What is the benumbing power possessed by the tentacula of the Hydra it is difficult to conjecture; some writers attribute it to a tor-pifying secretion ; others surmise the discharge of an electric shock ; but whatever be its nature, its effects are sufficiently potent to prevent the escape of the animal subjected to its influences.\nNo sooner is the prey thus stricken motionless than the tentacle against which it impinged begins slowly to contract and drag it towards the orifice of the mouth. It would seem that the slightest effort on the part of the animal seized would be sufficient to tear off the almost invisible gelatinous arm of the polype, yet not more surely does the angler land a trout by means of his silken line, than the Hydra succeeds by its tenacious hold in securing its victim ; tentacle after tentacle is brought to bear upon it, and slowly it is approximated to the opening of the stomach of the polype in which it is about to be engulphed.\nWhen lodged in the stomach of its de-vourer, so thin and diaphanous is the distended bag of the Hydra\u2019s body, that the animal swallowed is still distinctly visible, and the microscopical observer would scarcely suspect that the pellucid film which covers it was capab\u2019e of producing much effect upon its substance. Gradually, however, the swallowed prey begins","page":21},{"file":"p0022.txt","language":"en","ocr_en":"22\tPOLYPIFERA.\nto lose its distinctness of outline, and its parts become dim and confused, for the process of digestion has begun, and speedily all that is digestible is dissolved, nothing being left but the hard shell and other intractable portions, which are at length expelled from the digestive sac through the same opening by which they were admitted.\nFrom the transparency of the Hydra, Trem-bley thought to be able to ascertain the manner in which the digested nutriment became appropriated, and observing that the polypes became coloured in accordance with the kind of food upon which they lived, proceeded to feed them with the red larvae of certain insects, in hopes of seeing how the colouring matter became diffused through their bodies, and in this he was partially successful ; the result of his experiments proving that it was through the medium of the granules floating in the semifluid transparent substance of the Hydra that the diffusion of the coloured particles was accomplished, the granules themselves assuming the tint of the coloured food, while the gelatinous matter in which they were suspended remained colourless.\nAnother remarkable fact observed by Trem-bley was, that the digestive powers of the Hydra had no influence over the tissues of its own body, for frequently he observed that the long-armed species swallowed their own ten-tacula along with their food, the former remaining quite intact while the latter was in process of solution, and on one occasion when two Hydrae had both of them seized on the same prey, and were contending for the possession of it, one of them decided the contest by swallowing the subject of dispute and his rival into the bargain. Naturally supposing that the death of the swallowed polype would be the result of such an apparently tragical termination to the dispute, Trembley was not a little surprised to see the successful polype disgorge his antagonist safe and uninjured along with the egestamenta of the meal, and to all appearance none the worse for its temporary incarceration.\nIf a Hydra be divided transversely, by means of a knife ora pair of scissors, both halves not onl}' survive, but in the course of a short time each moiety reproduces the portion of which it has been deprived, the hinder extremity developing a new set of tentacula, and the. anterior portion acquiring a sucker to replace that which was lost ; nay, it has been proved that even when divided into several fragments, eich piece retains its vitality, and in process of time regains all the characters of a perfect individual, just as the cutting of a plant speedily puts forth roots and leaves similar to those of the original stock from which it was taken.\nNot less wonderful than their capability of recovering lost parts after mutilation are the powers which they possess of multiplying their species by various modes of generation. The most usual manner in which they produce offspring is by gemmation, the nature of which, owing to the transparency of their bodies, they\nare admirably adapted to elucidate. The process by which this kind of reproduction is effected in the case of the Hydra is as follows. After keeping one of these polypes for a few hours well provided with food, a little bud or gemma is seen to sprout from some portion of the surface of its body, which at first seems to be a shapeless excrescence, but in the course of a short time assumes the shape of the parent animal by developing tentacula from around the oral orifice, which gradually becomes more and more distinct. For some time the newly formed polype remains attached by the little pedicle at its tail to the body of its parent, with which it seems to enjoy a sort of community of existence, the food caught and digested by the one passing freely through a little aperture in the caudal extremity of the young polype from one to the other. At last, when the growth of the off-sprout is completed, it detaches itself, and assumes an independent existence ; yet sometimes even before its separation is accomplished the bud of a third generation may be observed appended to the side of its body ready to undergo the same process of development.\nThe formation of the reproductive gemmae may even be determined by extraneous causes : thus Trembley noticed that by snipping the side of an adult polype with the points of a fine pair of scissors, a bud would soon develope itself from the wounded part ; and this experiment might be repeated again and again, both upon the original polype and the progeny thus made to sprout from its sides, until as many as seventeen have been obtained, all connected with each other,, and thus forming a little tree of living polypes.\nBesides the gemmiparous mode of reproduction, Hydrae have been occasionally observed to divide themselves spontaneously by transverse fissure, and thus separate into two animals, in the same way as some of the Poly-gastric animalcules.\nThe anatomy of the Hydra has been recently closely investigated by Corda, whose observations upon this subject are possessed of extreme interest.* According to this observer each tentacule of the Hydra consists essentially of a long, pellucid, and extremely delicate membranous tube (fig. 27) containing an almost fluid albuminous substance, which in certain definite localities swells into denser wart-like knots (b), arranged in a spiral line, along which are appended organs of touch (d), and also instruments of prehension (c). Situated within the tube, and running immediately beneath the above-mentioned nodosities, which are arranged in a quaternian series, are situated four longitudinal bands of muscular fibres of a slightly yellow colour (e), which seem to be the extensors of the tentacles.\nThese extensors of the tentacula are moreover united to each other by transverse muscular fasciculi (/) of the same colour as themselves, which Corda names adductors of the\n* Anatome Hydr\u00e6 fusc\u00e6 exposuit Augustus Josephus Corda, cum tabulis tribus. Acta acad. C\u00e6s. Leopold. Carol, natur\u00e6 curiosorum, vol. xviii.","page":22},{"file":"p0023.txt","language":"en","ocr_en":"POLYPIFERA.\n23\ntentacles, as he considers that when fully ex- up like a fan The observations of the same tended the tentacle is by their action folded writer lead him to consider that there is np\nFig. 26.\nHydra fusca.\na, natural size ; b, magnified, extended that the mouth is seen\ncommunication whatever between the interior of the tentacula and the cavity of the body, for the tentacle is filled up with the albuminous material in which are dispersed brown coloured granules, apparently of an oily nature.\nIn the wart-like nodosities which wind in a spiral course round the tentacula, Corda finds what he considers to be organs of touch (fig. 27, d, and fig. 28, 1, 2). Each of these consists of a delicate sacculus implanted in the wart-like excrescence (fig. 28, p), which encloses another (q), provided with thicker walls and containing in its interior a minute cavity (r). Every one of the singular bodies thus organized supports an almost imperceptible filament (s), completing the supposed tactile apparatus.\nIn the midst of every group of these filament-supporting vesicles was found an\n(After Corda.}\nmagnified, contracted, viewed vertically, so d, magnified, contracted ; e, foot.\ninstrument adapted to seize prey, which its discoverer names a dart (hasta). This apparatus consists of a transparent oval sac (fig. 28, /), imbedded in the substance of the tentacle (Jc), and furnished above with a small orifice (h). At the bottom of the sac is situated a saucer-shaped body (vi), upon which is placed a solid oval corpuscle (n), and this again supports a long and sharp spiculum (sagitta), composed of calcareous matter (o), capable of protrusion and retraction through the aperture h, apparently by the eversion and retroversion of the saucer-shaped bladder to which the oval basis of the dart, n(has~ tifer), is appended. Whenever the Hydra would seize any animal, the darts or the tentacle become extruded, and its whole surface is thus rendered tenacious. Yet this does not seem to be all ; it would appear that\nc 4","page":23},{"file":"p0024.txt","language":"en","ocr_en":"n\tPOLYPIFERA.\nFig. 27.\nHydra fusca\u2014 end of a tentacle extended, magnified.\na, investing membrane ; b, nodosities ; c, prehensile darts ; d, tactile cilia ; e, longitudinal, and f, transverse muscular fasciculi. (After Corda.')\nHydra fusca.\n1, 2. Tactile cilia and their sacculi highly magnified ; p, first sac ; q, second sac ; r, minute cavity ; s, cilium.\n3.\tPrehensile apparatus highly magnified; h, aperture ; i, epidermis of the tentacle ; h, first sac ; l, second sac; m, saucer-like body (vesica); n, oval basis (hastifer) ; o, dart.\n4.\tIntestinal villus highly magnified ; f foramen ; g, cavity of the villus.\n5.\tParticles of fat or oil. (After Corda.)\nthe sagitt\u00e6 are empoisoned, as an animal once laid hold of by the Hydra very speedily dies.\nAt the base of the tentacula, the opening of the mouth is surrounded with lips capable both of inflection and protrusion. This lip is similar in structure to the tentacles themselves, and is in like manner provided with tactile appendages, and with prehensile sagitt\u00e6 upon its external surface. These lips, by their contraction, shut and open the mouth at the pleasure of the Hydra, and, when the size of the animal is taken into the account, appear to be endowed with extraordinary muscular force. The rest of the body is quite devoid both of sagitt\u00e6 and of tactile organs.\nThe body of the Hydra, according to Corda, is covered externally with a membrane that consists of two layers, of which the exterior (fig. 29, a) is composed of large cells, whilst in the inner layer are contained the germina, of which we shall immediately have to make further mention.\nBetween the skin and the alimentary canal Corda announces the existence of a muscular layer (fig. 29, b), composed of dense cells, which are coloured, and appear to be filled with minute granules.\nThe innermost layer of all (fig. 29, c), from its position and texture, ought, according to the same author, to be called the villous coat (tunica villosa). This stratum lines the entire alimentary tract, from the margin of the labial processes as far as the anus, being divided at intervals by folds into numerous compartments. The villi of which this stratum consist are intimately connected with the muscular layer ; their shape is cylindrical, but they are of two kinds, some being perforated at their apex by a foramen, whilst the others are close. Each of these villi (fig. 28, 4) is a rounded, pellucid vesicle, the walls of which are thick, and probably contractile, and in those which are perforated the perforation would seem to convey nutritive matter into their interior.\nBehind the anal orifice there is a small, hollow, and contractile membranous prolongation (fig. 29, e), which constitutes the sucker, or foot.\nANTHOZOA.\nAlcyonid\u00e6. \u2014 The races of polypiferous zoophytes which next offer themselves for our examination may be described as consisting of a common body or central mass, over the surface of which are disseminated numerous polypes, all of which contribute to the nutrition of the community to which they belong. In the first family, Alcyonium, examples of which are abundant on our own shores, the substance of the polypary or general body, which may frequently be picked up upon the beach, appears tobe a shapeless lump of a tough gelatinous substance, upon which, to an ordinary observer, no indications of its wonderful organization are apparent ; so that we cannot wonder at its being so frequently passed by as an object devoid of interest. On putting one of these amorphous masses into a glass ol sea-","page":24},{"file":"p0025.txt","language":"en","ocr_en":"POLYPIFERA.\n25\nFig. 29.\nHydra fusca, containing the larva of an insect partially digested.\nwater, however, and allowing it to remain for a little time undisturbed, its real nature becomes apparent and a series of most interesting phenomena present themselves. The mass, which was at first opaque and of a dense texture, slowly swells and becomes more diaphanous, apparently by the absorption of the surrounding water into its substance, until, having attained its full dimensions, numerous dimples appear, studding its entire surface, each of which, as it gradually expands, reveals itself to be a cell, the residence of a polype, which, emerging from its abode, displays eight pinnated arms, and the entire Alcyon, thus studded with living flowers, presents a spectacle of extraordinary beauty, but if disturbed speedily withdraws from observation and again shrinks into its former shapeless condition.\nM. Milne Edwards* has thrown considerable light upon the organization of these beautiful structures by his indefatigable researches, the results of which we shall lay before the reader at some length, as they are of great importance in illustrating the economy of the polypiferous zoophytes.\nThe genus Alcyonide {fig. 30) has the polypes grouped together in great numbers upon the surface of a soft cylindrical polypary or common body, which consists of two portions. The lower portion (b), which is attached by its base to fuci or other submarine substance, is of a brown colour and firm texture, whilst the upper part is white, membranous, and extremely delicate, divided into branches the summits of which are crowned with elegant polypes (d) of almost microscopic dimensions. Each of these polypes has eight pinnated tentacles, in the centre of which is the opening of the mouth.\na, large superficial cells of the integument ; b, muscular stratum, the cells of which are very minute, granular, and coloured ; c, villous tunic; d, anus; e, hollow membranous prolongation or foot.\n(After Corda.)\nFig. 30.\nA group \u00f6f Alcyonides {Alcyonidium elegans) fixed to a marine plant, of the natural size. On two of the great divisions of the polypary the animals are completely developed, whilst in the third (e) the whole of the soft portion of the polypary is contracted and withdrawn within the basilar portion, a, branch to which the polypary is fixed ; b, foot or basilar\nportion of the polypary ; c, trunk or membranous portion ; d, polype-bearing branches ; f, yellowish spots occasioned by the presence of ovules in the inferior portion of the trunk. (After Milne Edwards.)\n* Ann. des Sc. Nat. tom. iv. 1835.","page":25},{"file":"p0026.txt","language":"en","ocr_en":"POLYPIFERA.\n26\nOn observing these zoophytes in the living state, each polype is seen to be capable of executing individual movements ; sometimes they expand their tentacles, or bend them inwards towards their mouth, or retract them into the interior of their bodies, or retreat entirely into the substance of the common polypary, as into a cell, without the neighbouring polypes at all changing their position. In this respect each polype is independent of the surrounding ones. Under other circumstances, however, this is not the case, for sometimes the common body of the creature evinces movements that influence all the polypes, and cause their simultaneous contraction ; and this contraction is occasionally continued to such a degree that all the soft upper portion shrinks into the coriaceous stem, so as to become imperceptible, as represented in the figure (fig-30, e). On separating one of the polypes\nFig. 31.\nAlcyonidium elegans. Upper portion of one of the polypes magnified, and opened longitudinally.\na, tentacles; b, mouth; c, stomach; d, inferior aperture of the stomach ; e, upper part of the abdominal cavity ; /, membranous partitions extending from the stomach to the walls of the cavity in which it is suspended (some of these are cut in the section, others are in place) ; /, longitudinal folds of the abdominal parietes continuous with these partitions ; g, the canals that surround the stomach and terminate in the tentacles : </, one of the tentacles laid open ; h, groups of spicules situated at the base of the tentacles ; k, filiform appendages to the stomach, probably hepatic. {After Milne Edwards.')\nfrom the common mass, and opening it under a microscope in a longitudinal direction, it is found that its central portion is occupied by a cylindrical stomach (fig* 31, c) which is open at both extremities, and presents internally eight longitudinal bands and a multitude of transverse folds : inferiorly it is contracted, and looks as if its termination was surrounded by a sphincter, although no muscular fibres are perceptible. At length the inferior contracted orifice of the stomach opens\ninto a wide cavity (d), which occupies the entire diameter of the polype, and is prolonged inferiorly into the substance of the polypary. The calibre of the stomach itself is much smaller than that of the body of the animal, in the centre of which it is suspended by means of eight membranous and extremely delicate septa (/), which pass between the outer surface of the stomach and the parietes of the polype, forming so many vertical partitions. By their upper extremity these septa are blended with the periphery of the mouth, and thus circumscribe between them eight longitudinal canals (g), which are continuous with the corresponding tentacles. These latter appendages are in fact entirely hollow, and present on each side of the cavity which they enclose a series of ten or a dozen little apertures opening into the pinnules along their borders.\nInferiorly, the eight interseptal compartments communicate freely with the great cavity (d), situated beneath the stomach, the membranous septa becoming gradually continuous, with eight longitudinal folds (/') that project into its interior. Just at the point where each of the membranous septa ceases to be continuous with the walls of the stomach and becomes free by its inner margin, may be observed a filiform flexuous organ (k), the nature of which appears to be glandular.\nThe common polypary from which these polypes issue is composed, as was stated above, of two distinct portions (fig- 30, b, c). The superior soft portion is found by dissection to be made up of an assemblage of longitudinal membranous tubes placed parallel to each other, and so closely conjoined that it is difficult to separate them, and in fact the hard base of the polypary is nothing more than a continuation of these tubes, slightly altered in their structure : those situated near the centre of the stem are only distinguishable by a slight thickening of their walls, but those near its circumference acquire a much harder consistence, their parietes being encrusted with multitudes of brown-coloured fusiform spicula, which appear to be composed of a cartilaginous substance and of carbonate of lime. These spicula are arranged in a longitudinal direction, and confer upon this part of the polypary its solidity and peculiar aspect. Near the circumference of the polypary many of the tubes seem to be obliterated by pressure of the contiguous parts. On tracing the tubular structure downwards towards the base, each tube gradually disappears, either by becoming obliterated, or by anastomosing with the surrounding ones, whilst superiorly it is found to be continuous with the abdominal parietes of a polype, the sheath of which it forms when it is in a state of contraction.\nThe tubes thus united into fasciculi are evidently analogous to the cavities into which the polypes of Alcyons, Corals, &c., withdraw. These cavities are generally called \u201c polypi-ferous cells,\u201d and some writers consider them as being species of cases or envelopes more","page":26},{"file":"p0027.txt","language":"en","ocr_en":"POLYP1FERA.\nor less distinct from the animals themselves ; but in the Zoophyte we are speaking of a superficial examination is sufficient to convince any one that these cells are in reality continuations of the bodies of the polypes themselves. The tubes which form the trunk (fig. 30, c), are in all respects similar to the free portion of the animal which is situated beneath its alimentary canal, and no line of organic separation can be traced dividing one from the other. It is not, therefore, into polypiferous cells that these little animals retire in the manner of Serpul\u00e6 or Dentalia, but they recede into themselves by a kind of invagination of their own bodies, the polypary, which seems to contain them, being simply a mass formed by an assemblage of the basal portion of all the aggregated zoophytes.\nWhen the polypes extend themselves, their mouths may frequently be seen to open and admit the surrounding water. This fluid, together with the alimentary materials suspended in it, penetrate into the digestive sac-culus, and afterwards pass into the great abdominal cavity, whence they are conveyed even into the tentacula by the eight canals placed around the alimentary tube. It thus results that the thin and diversely folded membrane, of which the bodies of these animals are formed, is everywhere bathed, both within and without, with the materials for respiration, and that all its internal surface receives the contact of the alimentary substances after their elaboration in the digestive sacculus. M. Milne Edwards likewise thought he perceived something like a circulation in canals contained in the parietes of the body ; but of this he was uncertain.\nNutrition of Alcyonide, \u2014 It is very generally admitted that in the case of these aggregated zoophytes the nutritious materials taken by one of the animals is shared with the neighbouring polypes; and this fact M. Milne Edwards has established beyond the possibility of doubt, as well as the manner in which it is effected. In an expanded Alcyonide he introduced, by means of a fine pointed glass tube, a coloured fluid into the abdominal cavity of one of the polypes, and immediately the injected material diffused itself, not only throughout the tubiform body of the individual so treated, but passed at the same time into the neighbouring polypes. The passages by which this communication is established are easy to discover, by making a longitudinal section of the body of the Alcyonide. It is then seen that some of these animals, whose tube-like bodies are prolonged deeply into the common mass, there terminate by culs de sacs, whilst others are not continued beyond the point where they join their congeners ; and in this case their bodies are found to be continuous with that of a larger polype, the basal portion of which descends lower down (fig* 32). The abdominal cavities of these animals are thus united, so as to constitute a kind of branched tube, possessed of as many heads and mouths as there are polypes derived from it.\n27\nThis condition of their nutritive system arises from the mode of their development by\nFig. 32.\nAlcyonidium elegans.\nA,\tone of the branches laid open to show the communication between the abdominal cavity of the principal polype and the interior of the young ones that spring from it ; the openings thus formed, (e, e, e,) are situated in the course of the longitudinal folds which perform the office of ovaries, a, tentacles of the principal polype ; b, c, d, the young polypes in progressive stages of development.\nB,\tthe lower portion of one of the longitudinal folds detached, showing the manner in which the ova are developed in it. (After Milne Edwards.)\ngemmiparous reproduction, which takes place as follows. A tubercle makes its appearance upon the surface of the body of an adult polype, which seems at first to be only a little c\u0153cal appendage developed from its parietes, its extremity being without any opening and the cavity in its interior communicating freely with the abdominal cavity of the individual from which it was developed. Shortly, however, as its development proceeds, a mouth and its surrounding tentacula make their appearance, an alimentary cavity becomes apparent, and the newly formed animal becomes, both in shape and size, exactly like the individual from which it sprouted.\nThis mode of reproduction, Milne Edwards remarks, does not occur at any point of the tegumentary surface. The reproductive gemm\u00e6 are only formed along the course of the membranous lamellae already mentioned, and the inferior opening of the body of the new polype is always so situated as to intercept one of the longitudinal folds in the abdominal cavity of the parent animal.\nBut the mode of reproduction by gemmas is not the only one by which the Alcyonides are multiplied. They produce also ova, or gemmules, by means of which their sedentary race may be disseminated ; and it is remarkable that the same parts which give birth to the gemmae above described perform likewise","page":27},{"file":"p0028.txt","language":"en","ocr_en":"POLYPIFERA.\n28\nthe office of ovaries. The ova are, in fact, developed in the substance of the longitudinal membranous folds from which the gemmae sprout. As they grow larger they project internally, and soon become pedunculated ; at last, when mature, they detach themselves from the ovigerous fold and fall into the abdominal cavity, whence an issue is afforded to them through the mouth of the polype. No ovule is ever developed from the parietes of the abdominal cavity intervening between the longitudinal folds ; and hence there can be but little doubt that these lamellae represent the ovaria of the animal.\nOn seeing the same organ producing sometimes buds, or gemmce, and sometimes ova, Milne Edwards was led to inquire into the cause of this difference in the mode of reproduction, which he conceives to be of a mechanical nature. In those parts of the polype which are not yet imprisoned in the growing mass of the polypary, reproduction is generally effected by the development of external buds, while towards the base of the polypary, where the constituent zoophytes are intimately united together by their outer surface and are surrounded by a sort of sheath, no external buds are formed, but the ovules make their escape into the internal cavity of their parent. Hence the distinguished zoologist, whose memoir we quote, is led to infer that, on the one hand, the mechanical obstacles to be encountered, and on the other the excitement occasioned by the contact of the surrounding element, determine this difference of procedure, and that the membrane which performs the functions of an ovary produces indifferently either ova or gemmae, according as it finds less resistance or is more stimulated on the inside or the outside of the abdominal walls.\nFrom the above details it becomes easy to explain how a single polype, by its reproductive powers, can form the complicated mass of the compound polypary of the Alcyo-nide, as well as the means whereby an organic continuity is established between all the individuals of the community ; also how the abdominal cavity of the primitive individual becomes common to all the young ones that sprout from it ; in short, how the little beings, thus united together, rather resemble a single multiple animal than an assemblage of distinct individuals. But with the advance of age this intimate union gradually diminishes. The communication between the abdominal cavities of the different polypes whose basal portions reach as far as the foot of the polypary is first of all interrupted by the ova, with which the lower part of these cavities becomes filled (fig. 33, f) ; and subsequently, by the pressure of the surrounding parts, the walls become confused, and all communication between the polype whose abdominal tube is thus obliterated and the polype from which it sprung is intercepted.\nThe polypary, instead of resembling a tree, all the flowers of which hold together and communicate by common parts, may now be\ncompared to a bouquet made b}7 cutting off the more or less branched twigs of a plant\nFig. 33.\n1 2\nAlcyonidium elegans.\n1,\ttransverse section of the body of one of the polypes, to show the manner in which the eight longitudinal folds are attached around the alimentary canal, forming as many longitudinal canals that extend from the abdominal cavity into the extremities of the tentacles.\n2,\ttransverse section of the basilar portion of the polypary, showing the continuation of the abdominal cavities of the polypes with their longitudinal folds, and the germs filling them.\nand collecting them in a bundle. The different groups of polypes united in the same polypary become thus independent of the neighbouring groups, and, as may readily be conceived, in time each polype can become individualized.*\nThe filiform organs (fig. 41, k), situated below the digestive cavity, are evidently not ovaria, as they have been considered to be by many authors, seeing that the ova are formed elsewhere; neither does M. Milne Edwards consider that they can be seminiferous organs, but is inclined to regard them as hepatic vessels.\nIn the genus Alcyonium the zoophyte is composed of two principal portions. The common central mass is of a coriaceous texture, porous, and somewhat like cork, being formed of a dense substance, which, when cut into pieces, feels gritty under the knife, owing to the quantity of earthy spicula diffused through its mass. Externally it consists of a reddish granular substance, in which the polype cells are excavated, but internally it is of a grey colour, and permeated by numerous tubes that descend towards the base of the zoophyte, and frequently run into each other. These canals are filled with a gelatinous fluid, and lined with a red material prolonged from the external layer.\nThe polypes which stud the surface are as fine as hairs ; but still, with the aid of the microscope, it is not difficult to distinguish the mouth, the vesicular stomach, the muscular envelope of the animal, the ovary, and the glandular organs which depend from the base of the stomach into the abdominal cavity of the polype. Its whole structure has been\n* Kaspail, Polypes d\u2019eaux douces.","page":28},{"file":"p0029.txt","language":"en","ocr_en":"POLYPIFERA.\t29\nwell described by Spix, and subsequently more in detail by Milne Edwards in the paper above refei\u2019red to. The following is the result of Spix\u2019s observations.\n\u201c The mouth is a small rounded aperture, which is very dilatable, and communicates immediately with the stomach. The mouth is surrounded by eight tentacles, having a papillary surface, and they appear to contain internally a multitude of little air bubbles. They are very sensible, for as soon as they are touched they retract, and the animal retires into its cell.\n\u201c The polype is retained in its domicile by a muscular membrane, which is very distinct from the walls of the stomach, and is almost cylindrical ; it descends from around the mouth, and is fixed to the edges of the cell ; it appears to form the tentacles and the stomach, as in Actinia. The contraction and extension of the polype is effected by this membrane.\u201d\nFor many days during which Spix watched these polypes he observed little globular bodies to ascend from beneath the stomach and issue at the mouth. By pressing gently he saw them glide as by a little orifice into the stomach, and by the same proceeding he succeeded in pushing them under it.\nHaving raised the muscular membrane at the point where it is fixed to the polype, he perceived at the bottom of the cell, and beneath the stomach, seven or eight globules contained in a bent canal (ovary), placed in a row. They gave to the canal the appearance of a row of vesicles. The globules are round ; those which are most developed red, each enclosing a multitude of ova.\n\u201c When the animal is drawn out of its shell, by tearing the muscular membrane, the ovary detaches itself from the stomach and remains at the bottom of the cell. But there is another grey body like a tail, which follows the stomach, and is attached to it opposite to the ovary. This body is round, very thin, and so slender that it does not fill the tube in which it is placed ; it is therefore difficult to imagine that it descends to the base of the zoophyte to unite with the rest.\u201d\nThe above account, it will be perceived, agrees very closely, as far as it goes, with Milne Edwards\u2019s description of the anatomy of the Alcyonidium ; but the last mentioned naturalist has prosecuted the investigation of these zoophytes still more minutely.\nIn the Alcyons, properly so called, the vascular system is very distinctly developed, and in Alcyonium stellatum, more especially, M. Milne Edwards was able to study it with facility. In this species he was enabled to detect upon the parietes of the abdominal cavity of the polype a variable number of minute apertures irregularly dispersed, which are in immediate communication with a system of capillary canals that traverses in all directions the spongy portion of the polypary formed by the external tunic of its component animals. For in this species it is very easily seen that while the internal tunic lines the abdominal\ncavity of the polype, the external layer, instead of being confounded with the former, as in\nFig. 34.\nAlcyonium stellatum. A portion of the polypary divided longitudinally, showing the ramifications of the vascular system in the spongy substance separating the abdominal cavity of the polypes ; on the parietes of these cavities the mouths of many of the vessels are seen. {After Milne Edwards.)\nthe protractile portion of the animal, becomes perfectly distinct from it at the point where it begins to enter into the composition of the polypary, at which its thickness becomes considerably augmented, its texture spungoid, and in its substance are deposited a number ot irregular crystals, composed of carbonate of lime mixed with a little colouring matter. In the tegumentary mass thus formed, the vascular canals ramify, anastomosing freely among themselves, so as to constitute a v\u00e4s-* cular network. These vessels are formed of very attenuated membrane of a yellowish colour, which is continuous with the internal tunic of the polypes, and is perfectly distinguishable from the dense tissue with which it is surrounded. The distribution of these canals is best displayed by cutting a thin slice of the mass of the Alcyon and removing the crystals with which it is filled by immersion in some dilute acid ; it is then seen that the canals are most numerous and of the largest size towards the extremities of the branches of the polypary, and that they establish frequent communications between the abdominal cavities of the different polypes. This organization evidently establishes a very intimate connection between the different polypes of the Alcyon. The fluids with which their bodies are filled must thus necessarily circulate in the entire mass of the polypary, and if each of the polypes has, on the one hand, an individual sensibility, and a distinct digestive cavity on the other, there is a vascular system common to them all.\nThe Alcyons, like the Alcyonide, are reproduced by ova, which are formed in membranous ovaria of precisely similar construction, and also by gemmae, which in the Alcyon are","page":29},{"file":"p0030.txt","language":"en","ocr_en":"so\nPOLYPIFERA.\ndeveloped around the pre-existent polypes, and thus augment indefinitely the number of individuals united upon one stock. There is, however, a very important difference observable between these two genera of zoophytes, in other respects so similar. In the Alcyons the abdominal cavity of the young polypes is not directly continuous with the abdominal cavity of their parent, and it is only by the intermedium of the vascular system described above that they are placed in communication with each other; a modification which depends upon another difference in the mode of formation of the reproductive gemm\u00e6. When an Alcyon stock is about to put forth a new branch, the spongy part of the polypary (that portion which is formed by the external tunic of the polypes and permeated by the vascular network) begins to increase in size at some determinate point of its periphery, and soon produces a tubercle of greater or smaller size, into which the vessels spoken of above are continued, and form numerous anastomoses with each other. At this early period of development the new branch presents no trace of polypes, but its vascular tissue is nevertheless already studded with calcareous crystals, and exactly resembles that situated in other parts of the common mass between the abdominal cavities of the adult polypes. It must, therefore, necessarily be traversed by the currents which circulate in the general vascular system. On dissecting one of these newly formed branches the vestiges of young polypes may be distinguished ; and if the sprouts examined are still further advanced, it is easy to distinguish the young animals within, already ossessing the form they will afterwards ex-ibit, but which have not yet established a communication with the exterior. At length, however, this communication is established, and the newly formed polype only differs from the pre-existing ones in its small size, and as it grows its increase causes the enlargement of the polypary of which it forms a part. In this case it is very evident that the part which gives birth to the reproductive gemm\u00e6 is no portion of the individual polypes of the Alcyon, but is common to them all. The generative tissue surrounds these little beings with a sort of living sheath, and produces in the interior of its own substance new polypes, quite independently of those previously in existence. These polyparies might therefore be compared to a sort of common ovary, the products of which are never completely individualised, but remain permanently lodged in its substance, and minister to the support of its existence and the aggrandizement of its tissue.\nThis singular mode of reproduction, M. Milne Edwards observes, seems at first sight to be very different from that observed in the Alcyonidium ; but, on reflection, a considerable analogy may be traced between them. In Alcyonidium the internal tunic of the abdominal cavity fulfils the functions of an ovary, and produces at determinate points both gemm\u00e6 and ova; whilst in Alcyon, on the\ncontrary, while the internal membranous layer gives birth to ova, the gemm\u00e6 are developed elsewhere, from the canals which permeate the common mass. But the membrane which forms these canals, and which is the seat of this kind of vegetative reproduction, is merely a continuation of the internal tunic ; and hence it is easy to understand how it may fulfil analogous functions.\nCorallid\u00e6.\u2014Hhe cortical polypes, as they have been named by authors, mainly differ from the Alcyonid\u00e6 from the circumstance that the fleshy cortex which constitutes the common polypary, instead of being merely indurated by the deposition of earthy spicula in its interior, secretes for itself a solid central axis, upon the ramifications of which it is spread out, and thus enabled to form itself into arborescent expansions, of dimensions such as would be quite unattainable without this arrangement. The composition of this central axis varies in different genera ; sometimes it is dense and stony (Lithophyta) ; sometimes flexible, and composed of a horny substance (Keratophyta) ; this difference is, however, of no physiological importance, for very frequently the two substances are secreted in the same individual in different portions of its substance. The solid element in the Lithophyta is carbonate of lime ; in the Keratophyta it is concrete albumen,\n\u201c A species of Gorgonia, of a black colour and high polish, like black sealing-wax (Anti-\nFig,. 35.\nBranch of Gorgonia Umbraculum slightly magnified.\npathes?), examined by Mr. Hatchett*, was found, by immersion in dilute nitric acid during 28 days, gradually to become transparent and of a bright brownish yellow. In this softened state it was steeped two days in water, and was then opened longitudinally ; by this the whole structure became apparent, and consisted of thin coats or tubes of a beautiful transparent membrane, which beginning from a central point gradually became larger, according to the order in which they receded from the centre. These membranes were so delicate that the fibrous texture could scarcely be discerned.\nThe acid in which these had been steeped was tinged of a very pale yellow. Ammonia being added changed it to a deep yellow or orange colour; but the transparency of the liquor was not disturbed by this or any other pr\u00e9cipitants which had been employed in the former experiments.\n* Phil. Trans. 1800.","page":30},{"file":"p0031.txt","language":"en","ocr_en":"POLYPIFEFA.\nFig. 36.\n31\nGorgonia nobilis. A small detached portion magnified.\nWhen this Gorgonia was exposed to a red heat, it crackled and emitted a thick smoke, with the smell of burnt horn. The shape was soon destroyed, and a compact coal remained. By continuing the red heat, a very small portion of white matter was obtained, which, as far as the quantity would allow, proved to be muriate of soda with some carbonate of the same.\nThe results of the experiments on certain Gorgoni\u00e6, such as Ceratophyla, Flabellum suberosa, pectinata, and setosa, were not a little remarkable; for when the two portions which compose these Gorgoni\u00e6, viz. the horny stem and the cortical substance with which it is coated, were examined separately, it was proved, \u2014\n1st, That the stems of these Gorgoni\u00e6 consist of a substance analogous to horn, and that the horny matter contains a quantity of the phosphate of lime, but scarcely any of the carbonate.\n2d, That the cortical part consists principally of the carbonate of lime, with very little or none of the phosphate ; and the carbonate is deposited in and upon a soft flexible membranaceous substance, which seems much to approach the nature of cuticle.\nThe coral of commerce, Corallium rubrum, is, perhaps, one of the most interesting\nexamples of this division of Polypiferous zoophytes. In its living state this animal resembles a short stunted tree fixed to the surface of the rock by a broadly expanded base, from which it rises, at first with a single stem of varying magnitude, which soon divides into branches so as to resemble a leafless shrub rising to the height of about 18 inches. The central axis of the coral is of stony hardness, insomuch, indeed, that to this circumstance it owes its principal value in commerce, on account of the high polish of which it is susceptible. In the growing coral this stony centre is entirely invested with a fleshy cortex that constitutes the living portion of the zoophyte whereby the central stem is deposited, and the whole external surface is studded at intervals with polypes, in structure exactly resembling those of the Alcyonid\u00e6, both in the number of their arms and general structure. During the autumnal months gemmules are formed in the ovaria of these polypes, which are described as. being at first white, but afterwards of a bright red colour ; these detach themselves separately from the little white groups with which they were originally connected by filaments or umbilical cords. They escape thus into the body of the polype, behind its stomach, where they are seen to be perfectly","page":31},{"file":"p0032.txt","language":"en","ocr_en":"32\nPOLYPIFERA.\nfree, and change their position by means of their vibratile cilia. When the polypes are expanded, the sea-water has a free passage through the stomach to the gemmules, which receive new vigour from its influence, and they advance towards the open posterior part of the stomach, become entangled in its aperture, pass through the stomach, and escape through the mouth. They then move about, by means of their cilia, in search of a place where to fix and develope themselves.\nThe stony branches of the Coral are sufficiently short and strong to resist the violence\nof the sea, which otherwise would break so fragile a substance, but in the Gorgoni\u00e6 and Antipathes the ramifications are so long and slender, that they would inevitably be broken by the movements of the surrounding water, were it not that the nature of their central axis is materially modified. This part of their structure is therefore very considerably modified in its texture, and being composed of flexible materials is enabled to bend beneath the passing current and rise again uninjured, while in the Isis Hippuris {fig. 37) a similar result is obtained by combining the horny and calcareous\nFig. 37.\nIsis Hippuris.\nmatter in alternate joints. In these latter polyparies, however, although their central axes are principally composed of corneous substance disposed in concentric layers, the living cortex itself is full of granules of a calcareous nature mixed with colouring matter that varies in different genera, and as this cortex dries in a thick layer upon the central stem when the Gorgonia is removed out of the water, the varieties of colour exhibited bv these zoophytes is conspicuous even in our cabinets. Cavolini* prosecuted for two successive years, 1784 and 1785, his researches on the structure of Gorgonia verrucosa (Lam.), * Abhandlung ueber Pflanzen-thiere, p. 48.\nand found the anatomy of the polypes dispersed over the surface of each branch to be similar to that described above as common to the Alcyonid\u00e6 and Coral ; he detected the position of the ovaria at the base of each polype, and observed that the ova were discharged through eight small oviducts that open between the bases of the eight tenta-cula. These ova he describes as ciliated gemmules which, on their escape, swim to and fro in the surrounding water, and asserts that he saw a portion of Gorgonia, only eight inches high, discharge ninety of these in the space of an hour from the different polypes studding its surface.","page":32},{"file":"p0033.txt","language":"en","ocr_en":"POLYPIFERA.\nMadreporid\u00e6 : Madrephyllid\u00e6.\u2014 The next group of Polypiferous zoophytes may very properly be called Madreporygenous, seeing that it is by their agency that vast masses of calcareous matter are constantly in process of deposition, which by their immense accumulation not only form coral reefs and islands in tropical seas, but have powerfully contributed to modify the face of our planet. The manner in which these huge territories of newly formed land are constructed by the silent labours of these humble beings is now tolerably well understood.* In climates where the heat is intense, in enclosed and tranquil bays, the saxigenous corals are found to grow upon submarine rocks, which they encrust to a considerable depth. It is upon gentle declivities and where the sea is shallow, that the largest masses of madrepores are met with. In quiet water they spread extensively, otherwise they only construct small masses formed by species which suffer least from the agitation of the waves.\nIt is asserted that some reefs rise from immense depths like perpendicular walls, but,, although it is true that such reefs exist, they are not formed exclusively of madreporic rock, for the madreporygenous polypes can only exist at depths where they enjoy the influences of light and air, and consequently could not possibly grow at 1000 or 1200 feet below the surface. The sea, which breaks furiously upon such reefs, would inevitably destroy them, if they alone composed the cliffs; but the fact is, that sheltered from the waves in the hollows of pre-existing rocks, they contribute to increase their bulk.\nCorals found upon elevated tracts of the South Sea islands and Australia have no doubt been thrown up by volcanic agency, which raised the bottom of the sea where they were formed.\nWhen, under the shelter of submarine rocks, polypes have raised their abodes to the surface, they remain uncovered for a little time during the lowest tide. Storms turn up from the bottoms of the shallow waters sand and mud, which become entangled and fixed in the interstices of the madrepores, so that the summit of this new island comes to remain continually above the surface, and the waves can no more destroy what they have contributed to construct ; its circumference gradually enlarges, and its edges grow higher by the addition of fresh sand. According to the direction of the winds or currents it may remain long barren, but if by the action of these two causes, the germs of vegetation are brought to it from neighbouring coasts, it becomes covered with verdure, by the gradual decay of which vegetable soil accumulates, until at length it becomes fitted for the abode even of man himself.\nTo describe all the various forms of the madreporygenous zoophytes would be useless, even were it possible within the limits permitted to us ; we shall therefore content our-\n* Quoy et Gaimard, Voyage de TUranie*\nVOL. IV.\n33\nselves with selecting those genera which have been most attentively examined, and from their history the reader will have little difficulty in obtaining a clear insight into the economy of the rest. Throughout the entire series the vital agent will be found to present itself in the form of a soft, gelatinous crust wherewith the exterior of the polypary, whatever may be its shape, is closely invested, or more correctly speaking, the calcareous particles are gradually deposited in its cellular interstices, and thus moulded into form. Externally this living cortex is generally studded with polypes lodged in cells excavated in the polypary, the forms of which are indicative of the species.\nThe Fungi\u0153, although their calcareous skeletons are to be met with in every cabinet, have never, as far as we are aware, been brought to our shores in their recent state; and accordingly their living condition has been very erroneously described by several modern writers. The dried framework of the Fungia agariciformis owes its name to its similitude to a mushroom, which it closely resembles. In shape it is a circular disc, the inferior surface of whieh is flat, and rough, and granular, while superiorly it is convex, its upper surface being arranged in broad calcareous lamellae, which radiate from the centre to the circumference of the mass {fig. 38). According to Forskal*, when in a living state, the whole superficies of the Fungia is covered over with a thin gelatinous layer, which dipping in between the radiating lamellae coat every part of the calcareous surface, but without any polype or appearance of tentaeula. The gelatinous coat, indeed, seems exactly to represent the living crust of the sponges, being entirely destitute of anything like a stomachal cavity, and apparently nourished altogether by its general surface, which must appropriate nutriment from the surrounding water. The living film which thus encrusts the Fungia is the only agent em-. ployed in the construction of the beautiful calcareous basis that supports it, each particle of which, as it is derived from the circumambient element, is added, by interstitial deposit, to the growing fabric, which is thus built up in the regular form belonging to the species. The upper surface of the living animal has been observed to be provided with bubbles of air, apparently secreted by the living film in which it is imprisoned. These bubbles seem, to have no regularity of arrangement, but nevertheless play an important part in preserving the Fungia from destruction ; for the mass being in its adult state unattached to any foreign body, is of course quite at the mercy of every passing wave, which, taking it up, might capsize it, and thus bury its upper surface in the sand; but the air bubbles placed there, as it were in anticipation of such an accident, acting the part of floats, always by their buoyancy keep the living side uppermost, and allow the creature to\n* Flora \u0152gyptiaco-Arabica ; Hauni\u00e6, 1775.\nD","page":33},{"file":"p0034.txt","language":"en","ocr_en":"34\nPOLYPIFERA.\nFig. 38.\nFungia. A portion of the calcareous basis has been denuded of the gelatinous coating. (After Forskal.')\nsettle down again at the bottom in its right position.\nThe living gelatinous crust which covers the surface of the lamella is not merely a superficial investment, as it has been described by some writers, but, as will be proved hereafter, enters essentially into the formation of the substance of the stony mass, upon the component parts of which it exerts a vital influence.\nThe Fungia described above inhabits the Red Sea, and is entirely destitute of tentacular appendages ; but the generality of those brought from tropical climates have their upper surface covered with numerous cylindrical tentacula (fig. 39), which, when expanded, give it very much the appearance of a true Actinia. When these tentacula are touched, they shrink, and partially hide themselves between the radiating lamellae. The stony polypary has in this species been proved to be in reality lodged in the interior of the animal\u2019s body, the soft parts of which cover the lower surface as well as the upper, and even form a fleshy ring around the margin of the disc, giving the idea of the foot of an Actinia.\nIn the centre of the upper surface there is an oval aperture (fig. 39), which has been regarded as the creature\u2019s mouth ; but there does not seem to be any stomachal cavity. The tentacula of some species are so large, that they look something like leeches ; they have, however, no terminal orifice, as those of the Actinias have, but seem to fill them-\nselves with water by a kind of interstitial absorption.\nThe polype-like investment of a Fungia of this description * is fleshy, membranous, and flattened, generally circular or oval, having in its centre an elongated opening ; the animal is thicker at this part than at the circumference. The Fungia then is a broad polype, slightly fringed around its margin, and secreting, by its inferior surface, calcareous matter, imitating all the natural forms of the animal, and even its accidental positions. All the septa are triangular, much thicker at their base than at the summit, where the fleshy crust is so thin, that if the polype is colourless it is imperceptible; but it is distinct in coloured species. Upon the sides of the laminae are little tubercles, which, penetrating the fleshy folds of the animal, cause it to adhere so firmly to the calcareous basis, that it is impossible to detach it, except by piecemeal. In the natural state, the mouth of the polype is prominent, but it does not project beyond the fissure which contains it ; at the least touch the whole creature contracts, so that it would seem that there was no animal. During growth, as the laminae become more elevated, the interstices are gradually filled up from the bottom ; but the increase of the Fungia in thickness is very limited, as, in fact, is its lateral extent, the diameter rarely exceeding six or seven inches.\nGenerally the gemmules of Fungiae are developed upon the sand, without, however, ad-* Quoy et Gaimard, Voyage de l\u2019Uranie.","page":34},{"file":"p0035.txt","language":"en","ocr_en":"POLYPIFERA.\n35\nhering to it; sometimes they are fixed to other madrepores by an elongated pedicle, and occasionally, as we learn from a recent author, grow from the substance of the parent zoophyte. His account is as follows : \u2014 \u201c The specimens of Fungia which I have seen generally lie in hollows of reefs, where they are in some degree protected from the more violent agitation of the sea by the sur-\nrounding portions of branching coral which enclose the hollows, and at the same time allow sea-water free access through their interstices. It appears that although the older and larger individuals are quite unattached and present no mark of former attachment, yet that in the young state they are fixed sometimes to rocks, and frequently to the dead remains of their own species ; in this\nFig. 39.\nFungia actiniformis. (After Quoy et Guimard.}\nstate they grow upon a footstalk, and generally remain attached till they acquire the size of nearly an inch in diameter, when they separate at the top of the peduncle.\u201d\n\u201cAt this time the coral, when divested of the fleshy part, shows a circular opening beneath, through which the radiating, plates of the upper surface are visible. In a short time a deposit of coral matter takes place, which cicatrises the opening, the marks of which, however, can be traced for a considerable time ; at length the increase of this deposit, which continues with the growth of the animal, entirely obliterates all appearance of it. It will not appear surprising that this circumstance should hitherto have been unnoticed, when it is recollected that it has very rarely occurred to naturalists to visit the\nplaces of their growth, and that to general collectors the smaller specimens would appear hardly worth the trouble of preserving and bringing home.\u201d\n\u201c The sheltered situation in which the Fungi\u00e6 are found are particularly well adapted to their nature, as they would be liable to injury if they were exposed to the full force of a stormy sea ; and the circumstance of their being attached in the young state is a beautiful provision of nature for their preservation at that period, as from their light weight, when first developed, they would, il unattached, be exposed to great injury, even by a slight agitation of the water. I have also to remark upon this fact, that the Fungi\u00e6, while attached, agree in every respect with Lamarck\u2019s genus Caryophyllia, more especially in their","page":35},{"file":"p0036.txt","language":"en","ocr_en":"36\tPOLYPIFERA.\nearly state, when the radiating plates are first developed. At this time their upper discs are scarcely larger than the stem, but they soon begin to spread, and show indications of their characteristic form. There are many instances of smaller individuals remaining fixed to large ones in a living state, and such specimens are not unfrequent in collections of corals. But in all cases that I have seen, the younger ones are attached to the under side of the old one, and I believe them to be cases of accidental attachment.\u201d\n\u201cIn Ellis\u2019s Zoophytes (p. 146) is the following passage, quoted from Rumphius, in regard to the animal of F. agariciformis. \u2018 The more elevated folds or plaits have borders like the denticulated edge of needlework lace; these are covered with innumerable oblong vesicles, formed of a gelatinous substance, which appear alive under water, and may be observed to move like an insect.\u2019 I have observed these radiating folds of the animal, which secrete the lamell\u00e6, and which shrink between them when the animal contracts itself on being disturbed. They are constantly moving in tremulous undulations, but the vesicles appeared to me to be air vessels placed along the edges of the folds ; and the vesicles disappeared when the animal was touched.\u201d\n\u201c This arrangement of air vessels would very materially assist in keeping uppermost the convex disc of the coral, and be of vital importance to the young polype at the time of separation, and subsequently in keeping it upon the surface of its sandy bed ; or if they were moved by a sudden roll of the sea, which would lift even the most ponderous and possibly convey them a considerable distance, they would be again deposited in their natural position. That they have no power of turning themselves I proved, during a sojourn of six weeks at Tahiti, by placing a healthy specimen with its upper surface downwards, during which time it remained in the position placed, and the vitality of the points of contact with the rock upon which it was laid was destroyed. In Fungia limacina I have seen instances where the coral, having been accidentally placed and permanently fixed in such unusual positions, has adapted itself to its new situation, by increasing upon its edges, and forming a new convex surface.\u201d\n\u201c As long as the young Fungia retains the form of a Caryophyllia, it is entirely enveloped by the soft parts of the animal ; but as the upper disc of the coral spreads and it assumes its characteristic form, the pedicle is left naked, and the soft part extends only to the line where the separation afterwards takes place.\u201d\n\u201c I consider the cases in which young Fungi\u00e6 are found fixed to the under side of others of the same species to arise from the accidental attachment of the young polype when detached from its parent, and by the motion of the water floated underneath a larger one of its own species, the edges of which were not so even as to touch the rock or coral on which it rested at every part of its surface.\nIn such cases the soft parts of the older specimen would continue to cover the short stem of the younger individual, and hence its separation from its pedicle would be prevented.\u201d\nThe genus Polyphyllia is, in its essential structure, closely allied to the Fungi\u00e6 described above, but the upper surface of its stony polypary, instead of being furnished with lamell\u00e6, all diverging from the same centre, is covered with numerous smaller laminae, diverging from different centres, but generally arranged perpendicularly to the long axis of the polypary. In the living state all the superficies of a Polyphyllia are covered with numerous polypes, the bodies of which are confluent at their margins. Their mouths are placed without any regular order, but open here and there in the depressions that separate the numerous laminae ; they are of an oval or roundish form, and slightly fringed around their margins, but without any tentacula. These latter are distributed over the whole upper surface of the compound animal, and seem to be formed by prolongations of the fleshy substance which covers the more prominent lamell\u00e6, but present no appearance of being arranged round a given centre. When taken out of the water they disappear, shrinking between the laminae. The polypes themselves in their structure resemble those of the other Anthozoa, presenting the usual arrangement of a stomach and ovigerous filaments.\nVery nearly related to the Fungi\u00e6 are the Mcandrince {fig. 40), the poly paries of which\nFig. 40.\nA.\tMeandrina cerebriformis.\nB.\tA portion magnified, showing the polypes occupying the bottom of the furrows. (After Quoi/ et Guimard.}\nare globular, their surfaces being grooved with sinuous furrows, the meandering\u00ab of which give name to the genus. The Meandrin\u00e6 have all a determinate growth which they do","page":36},{"file":"p0037.txt","language":"en","ocr_en":"POLYPIFERA.\n37\nCaryophyllia\nhas\nnot exceed, and consequently their masses are always separate, and not agglomerated like those of Madrepores, Astre\u00e6, &c., which grow indefinitely. The polypes of Meandrin\u00e6 occupy the bottom of the furrows, and are variously coloured in different individuals. When attentively examined, they are seen to form membranous expansions, which cover the lamellae of the ambulacra but rarely mount to the summit of the ridges, the whiteness of which indicates the line of separation between the different rows of polypes. They are, in fact, Caryophylliae or Fungiae much elongated. They secrete, from all parts of their body, a mucosity so abundant that, on reversing the mass, it runs off like albumen. The same is the case with Agaricae and Pavoniae.\nWhen exposed to the sun the living part becomes black by putrefaction.\nOn splitting the globular stony polypary of a Meandrina, the mode of its growth is very beautifully demonstrated. Commencing at the centre of the mass, the deposition of calcareous matter is seen to have progressed regularly in all directions, layer after layer, like the coats of an onion, every stratum having, of course, in turn been the outer surface of the polypary and marked with the same sinuosities or convolutions as are exhibited by the existing exterior, affording a very striking illustration of the mode of growth common to all the litho-phytous zoophytes, and of the mathematical precision with which they build their wonderful edifices.\nWe are progressively conducted through various intermediate species of laminated zoophytes from the broadly extended disc of Fungia and the diffuse surface of Meandrina to more concentrated forms of these lithogenic polypes. In Turbinolia (fig. 41), for example, the superior luminiferous disc is evidently an approximation to the structure of the real polype-bearing cells of Caryophyllia (fig. 42), where the stony polypary is made up\nFig. 41.\nspecies already described ; the principal difference between them being in the number of the tentacula, corresponding to that of the radiating lamellae, wherewith their bases correspond, which, in the many-armed species,\nFig. 42.\nfasciculata. A portion of the calcareous polypary been denuded. (After Quoy et Gaimard.')\nare numerous. Another important circumstance in the economy of these races of zoophytes is, that the radiating lamellae contained in the abdominal cavity situated beneath the stomach are progressively calcified from below upwards, and thus become converted into stonv plates instead of membranous septa, so that on making a section of these polyparies perpendicular to the axes of the cells, each cell presents the appearance represented in fig. 43 ; and even in fossil polyparies,\nFig. 43.\nTurbinolia rubra. (After Quoy et Gaimard.)\u2019\nof infinite numbers of distinct cells united to each other by an interposed calcareous cement, and every one of them containing a many-armed polype, the essential structure of vhich is similar to that of tb\u00e7 eight-armed\nSection of calcareous polypary of Astrea abnormalis.\n(After Quoy et Gaimard.)\nwhere the whole substance of the mass has become solidified, the original radiating lamin\u00e6 are permanently conspicuous, as many a marble chimney-piece will testify. In their living state the polypes inhabiting these cells are most variously and gorgeously coloured, so that when protruded they are indescribably beautiful, resembling the flowers that adorn the gayest parterres in our gardens. Yet if such be the interest of this spectacle, even to the eye of the ordinary observer who amuses himself by contemplating the indications of life exhibited by a little patch of a coral reef, what\nD 3","page":37},{"file":"p0038.txt","language":"en","ocr_en":"38\tPOLYPIFERA.\nmust be the feelings excited in the mind capable of appreciating the result of the labours of these silent agents in the economy of our world ! Let us imagine for a moment the stupendous scene which the mental eye may view at the bottom of the ocean. Vast districts of the globe spread over with a carpet of this living crust, studded, as thickly as are our fields with grass, with hungry flowers of every various hue \u2014 all actively employed in carrying on the great progressive work \u2014 depositing, with unobtrusive diligence, from age to age, the chalky masses we have been describing\u2014slowly, but unremittingly, the mighty fabric grows, until at length it peers into the world above the waves which nourished it, and forms a land where all before was sea, soon to be peopled with fit occupants, or possibly by the volcano\u2019s breath upheaved into the clouds, to become the nucleus of a country like our own, from which intelligence may pour forth to irradiate the world !\nPennatulid\u00e6. \u2014 The Pennatul\u00e6, or Sea-pens, are distinguished by Cuvier from the other families of cortical polyps under the title of \u201c Polypiers nageurs,\u201d or swimming Polyparies, and are remarkable from the circumstance that, although they possess an internal calcareous support, they are not attached to foreign bodies, but seem at liberty to swim about in the sea. The Pennatul\u00e6, properly so called, several species of which are met with on our own shores (fig. 44), have a\nFig. 44.\nPennatula grisea. (After Slainville.')\ncentral stony axis, coated over its greater part with a thick living cortex, the substance of which presents a somewhat fibrous arrangement, and is capable of movements of contraction sufficiently forcible to permit of locomotion. The lower portion of the stem, which strikingly resembles the barrel of a quill, is entirely denuded of this living crust, and when found in the bays upon our coast, this part is generally stuck into the mud at the\nbottom like a pen into an inkstand, whilst the two upper thirds of the stem are furnished on each side with broad lateral appendages, comparable to the barbs of a quill, from the margins of which are protruded the rows of polypes which minister to the support of the common body of this compound animal. The lateral barbs are supported by calcareous spicula developed in their interior and imbedded in their fleshy substance, but having no other connection with the central stem.\nIn other genera the alary appendages are without any internal spines, or sometimes entirely wanting, in which case the polypes are situated upon the stem itself.\nIn Rcnilla the body consists of a broad kidney-shaped disc without any barbs, the polypes in this case being distributed over one surface of the disc, and in Veretillum the polypebearing part is a cylindrical finger-shaped mass. The central axis in both the last-named genera contains but little calcareous matter, and in the whole family' the individual polypes closely resemble those of the Alcyonid\u00e6 in their organisation. In Veretillum the substance of the general mass is excavated into wide canals that extend in the direction of the central axis of the body, and terminate in wider cavities within the lesser obtuse extremity.\nMany of the Pennatulid\u00e6 are eminently phosphorescent.\nThe polypes of this group of cortical zoophytes have eight pinnated arms, and seem to be organised upon the same plan as those of the Corallid\u00e6.\nActiniad\u00e6.\u2014 The Actini\u0153, or Sea-ane-monies, so common on our coasts, known also by the name of \u201c fleshy polypes,\u201d are evidently nearly allied to the preceding family, but instead of secreting a calcareous polypary have their bodies entirely composed of a fleshy substance which, in appearance at least, is not very remote from muscular fibre. The ordinary Actiniae are of a conical form, the base of the cone forming a strong sucker, whereby they attach themselves to foreign bodies, while, at the opposite extremity', which is truncated, is the opening of the mouth, surrounded with several rows of retractile tentacula, wherewith they seize their prey. They often elongate their bodies, and, remaining fixed by their base, they stretch from side to side as if to seek for food at a distance, and when thus stretched out they are very flexible and transparent, but shrink on being irritated, and contract themselves so firmly that it becomes almost impossible to distinguish them from the surface to which they are attached. According to some writers they can change their place by gliding upon their base; or detaching themselves entirely, they become swollen by the imbibition of water, and thus being rendered nearly of the same specific gravity as the surrounding element are driven about in the sea until they choose to fix themselves again, when, by expelling the fluid from their bodies, they sink again to the bottom, and settling down become again fixed. It is even asserted that having detached their suckers they can turn","page":38},{"file":"p0039.txt","language":"en","ocr_en":"POLYPIFERA.\n39\nthemselves mouth downwards, and crawl by means of their tentacula, but our observations have failed to confirm these remarks.\nThe substance of the Actinia is entirely composed of transverse and perpendicular muscular fibres, which cross each other, the meshes of this interlacement being occupied by a multitude of granules, seemingly of a glandular nature, giving to the surface of the\npolype, which is covered with a gelatinous membrane, a tuberculated appearance. Externally this fibrous membrane forms the parietes of the creature\u2019s body, expanding interiorly into the basal disc, and superiorly, after forming a sphincter-like ring around the tentacula, is continued inwards to form the tentacula themselves (fig. 46, a), and then, becoming more delicate in its texture, reflected\nActinia alcyonoidea. (After Quoy et Gaimard.)\ninto the interior of the body so as to form the stomachal cavity (b). Extending between the internal surface of the outer walls of the body and the exterior of the stomach are numerous longitudinal septa (c), evidently the homologues of the vertical partitions of the Alcj o-nide (fig. 31,/), and were these calcified by the deposition of stony matter in their interior they would represent exactly the radiating septa in the cells of the polypary delineated in fig A3.\nAs in the preceding genera these membranous septa support the organs of reproduction, which are constructed after the following manner.*\nThe whole interior of the Actinia, between the stomach and the muscular parieties of the body, is divided by means of the septa into numerous longitudinal cavities, each of which communicates with the bases of two or three of the tentacula around the mouthf and encloses an ovary. Each ovary is composed of three or four cylindrical and coherent tubes of extreme delicacy, which, towards the base of the\n* Spix, Annales du Museum d\u2019Hist. Nat. tom. 13.\nf For an admirable diagrammatic representation of the structure of Actinia, the reader is referred to Dr. Sharpey\u2019s Article \u201cCilia,\u201d Yol. I. fig. 297.\nFig. 46.\na\nSection of \u201cActinie Clouf\na, Tentacles surrounding the mouth ; b, stomach ; c, longitudinal septa prolonged and enclosing the ovaries. (After Quoy et Gaimard)\nD 4","page":39},{"file":"p0040.txt","language":"en","ocr_en":"40\tPOLYPIFERA.\nanimal, are prolonged into a common canal, their opposite extremity tapering to a point as the eggs become smaller, each ovary containing about sixty eggs. The common tubes of two neighbouring ovaries unite into one as they issue from the longitudinal cavity, and this again joins the common canal of the next pair; the resulting duct, which is thus common to four ovaries, opens into the stomach. The openings of these terminal tubes are arranged in a zig-zag direction, some opening lower down, others higher up.\nReaumur* believed that the young issued by a slit on each side of the body, situated beneath the fold of the muscular envelope that surrounds the bases of the tentacula, but the supposed openings are merely folds of the skin, never perforate, and not always present. Nevertheless, as the tentacula are perforate at their extremities, and water is frequently forced out of the body through these openings, it is possible that some ova may become detached and issue through these organs.\nThe ova are round, yellow, and like little grains of sand. Ellis, Reaumur, Dicquemare, and Spix, all assert that Actiniae are viviparous. The latter observer states, \u201c 1 have several times seen them issue from the mouth of their parent perfectly formed. An Actinia that I have in spirit of wine contains a great number of eggs, each marked with an opaque spot that seems to contain the young animal. I have even one individual not larger than a hemp-seed, which seems hardly ready to quit its envelope, having neither the mouth nor the tentacula perfectly distinct. Moreover, I suspect that the eggs are sometimes hatched in the ovaria or in the stomach, and sometimes out of the parent. I am not sure but the animal may at the time of the expulsion of the eggs have its stomach turned inside out.\u201d\nThe number of eggs must be prodigious, each Actinia possessing upwards of a hundred ovaria.\nIt appears from recent researches that the Actiniform polypes are bisexual.\nIt is rendered extremely probable by the very advanced condition of the muscular apparatus in the Actinia that they likewise possess a nervous system. Spix in his experiments employed galvanism, which made the animal contract convulsively, and finding that the contractions were strongest in the neighbourhood of the base of the animal he was led to search for it in this part, and conceived that he had discovered it in this situation. \u201c Having raised by a slight incision the longitudinal muscles at their union in the middle of the base, I perceived with a magni-fying glass an interlacement formed by some pairs of nodules disposed around the centre which communicated by several cylindrical threads ; from each nodule two filaments ran forwards ; one was seen to run along the muscle, the other to pierce it, to divide into\n* Histoire de l\u2019Acad\u00e9mie des Sciences Naturelles, An. 1710.\ntwo branches, and, lastly, to lose itself in the longitudinal cavity formed by the floating muscles. The situation of the nodules and filaments is beneath the stomach, and their round figure would not allow me to confound them with the muscles, which are broad and riband-shaped, and still less as the latter putrified rapidly, while the former remained entire.\u201d*\nSome of the tropical Actini\u00e6f, which occasionally measure a foot in diameter, produce a stinging sensation when they are handled, and this stinging property is even communicated to the water that they absorb. There is moreover one remarkable circumstance connected with it ; namely, that it acts much more powerfully upon the skin, which it inflames, than upon the mucous membranes, and a drop received into the eye causes much less pain than when applied to the eyelids.\nThe Actiniae, although exceedingly voracious, will bear long fasting : they may be preserved alive a whole year, or perhaps longer, in a vessel of sea-water; but when food is presented one of them will devour two mussels in their shells or a crab as large as a hen\u2019s egg. In a day or two the shell is voided at the mouth perfectly cleared of the meat.\nTheir power of reproducing lost parts is scarcely inferior to that of the Hydr\u00e6. The Abb\u00e9 Dicquemare J describes some experiments on this subject, and states that when a horizontal section is made through one of these creatures the tentacles still seized and swallowed food, which sometimes passed through the body, at other times was expelled from the mouth digested. In about two months tentacles grew from the other portion, and it ate food, soon becoming a perfect animal. He states that in this way he even succeeded in making an Actinia with a mouth and tentacles at both ends !\nAulozoa. \u2014 The third subdivision of Poly pi fera is composed of a series of zoophytes very different in their organisation from those embraced by the two preceding. They have generally been named by naturalists Tubular or Vaginated Polypes, and are distinguishable from the circumstance that their living substance, instead of being external to the hard polypary, is in them enclosed in a calcareous or corneous tube, sometimes simple, but more frequently ramified, from which the polypes are protruded, either through a terminal aperture or from lateral cellules formed by the external envelope.\nThe Aulozoa are divisible into several groups, which we shall separately examine, beginning with the Tubularid\u0153.\nIn the Tubularia (fig. 48), as in all polypes unprovided with a complete digestive canal, there is an organic portion which brings all the members of the colony into communica-\n* Spix, Ann. du Mus. d\u2019Hist. Nat. vol. xii\u00ef. p. 444.\nt Quoy et Gaimard.\nX Phil. Trans, for 1773.","page":40},{"file":"p0041.txt","language":"en","ocr_en":"POLYPIFERA.\n41\ntion with each other, or forms in other words the body of the communitjq and from this common body buds are thrown out, from which ramifications are produced in all respects resembling those met with in the vegetable kingdom ; these constitute the trunk and branches of a tree, which, instead of bearing flowers, produces polypes provided with tentacula, a digestive cavity, and most frequently a reproductive apparatus.\nTentacular apparatus.\u2014 In the Tubularid\u00e6 the tentacula are situated, as in all polypes, around or in the immediate vicinity of the oral opening. Their number is very various, even in the same species, but the variations in their length are more apparent than real, for their contractile powers are such that they are constantly changing in their shape and dimensions, in which respect they resemble the Hydra described above. It is towards the extremity of the tentacle that this contractile power is most remarkable ; and when the organ is not fully stretched out, it is enlarged or dilated near the end, insomuch that some authors have erroneously looked upon this part as performing the office of a sucker.\nThe disposition of the tentacula varies in different genera. The genus Eudendrium has a single row of tentacula, which are alternately placed a little more internally and externally. The genus Tubularia, properly so called, has a second row of shorter tentacles immediately surrounding the proboscidiform prolongation which constitutes its mouth, and in the genus Stipula (Sars) there is an additional row situated between these two, so that there are genera with one, two, or several rows of tentacula ; the lower row is, however, always the longest, and it is these that are persistent when there is only one rank. The tentacula are arranged in whorls in all the Tubularid\u00e6, except in the genus Syncoryna, in which they are distributed without regularity (fig. 47). No cilia are perceptible, either externally or in the interior of these tentacula, which, when highly magnified, appear to be entirely composed of transparent cells, closely agglomerated, and no traces of muscular fibre are by any means to be detected ; their movements seem to depend entirely upon the contractions of their component cellules, which are seen to diminish in size when the tentacle is shortened, and to expand during its elongation, preserving nearly the same shape, whence it may be concluded that their pari-etes are endowed with contractile powers. Professor Van Beneden indeed compares them to so many hearts placed endcto end, which, by their dilatation elongate, or by their constriction shorten or bend, the tentacle of which they constitute the substance.\nDigestive system. \u2014 In the Tubularid\u00e6 there is seen, situated in the middle of the tentacula, a sort of proboscidiform appendage, open in the centre, which is the entrance to the digestive cavity. The name of proboscis appears sufficiently applicable to this part, both on account of its situation and of\nthe changes of form which it continually undergoes. In its most usual condition it has the appearance of a protuberance provided at its summit with an orifice of very variable shape and size.*\nFig. 47.\nSyncoryna pusilla.\n1. A little group, twice the natural size. 2. A branch much magnified, a, the stalk ; b, a bud from which a polype is about to be developed ; b, a bud which is about to give rise to a long stalk ; c, body of the Syncoryna with its three rows of tentacula ; d, a Syncoryna having only two rows of tentacula. (After Van Beneden.')\nThe cavity of the proboscis leads into that of the stomach, but neither the one nor the other have parietes proper to themselves, but on the contrary seem, as in the Hydra, to be mere excavations in the substance of the polype. In the genus Coryne, the cavity of the stomach is circumscribed, so that each polype has a proper digestive cavity ; but in all the other genera belonging to this family, the stomachal receptacles of different individuals communicate mediately one with another, so that what is taken into the stomach of one polype may pass into those of all the individuals composing the colony. Thus, what is eaten by a few individuals profits the whole community, seeing that what one swallows may pass into the stomachs of its neighbours.\nWhen we examine a young,branch that is sufficiently transparent, a fluid containing irregular globules is seen to circulate in its\n* Recherches sur l\u2019Embryogenie des Tubulaires, et l\u2019Histoire naturelle des differents Genres de cette Famille qui habitent la c\u00f4t\u00e9 d\u2019Ostende, par P. J. Yan Beneden, Mem. de l\u2019Acad. Royale de Bruxelles, 1844.","page":41},{"file":"p0042.txt","language":"en","ocr_en":"42\n\u25a0 POLYPIFERA.\ninterior. There is no intestinal canal, all ex-crementitious matters being evacuated through the oral orifice.\nCirculation.\u2014The stems of the Tubularid\u00e6 are formed of the same kind of tissue as that which constitutes the body of the Polype, and each stem is hollow throughout its entire length. The tube thus formed is filled with a fluid containing globules, which is constantly in motion, a circumstance first observed by Lister *, but its course is by no means regular. Sometimes the globules mount up as far as the body of the polype, and then descend again by the same route ; if they come to a division of the stem, as is frequently the case in most genera, they may be sometimes seen first to penetrate into one branch, and then returning enter the other. In the ordinary Tubularia, described by Lister, a current may generally be seen ascending along one side and descending along the other. In the long and slender stems of Eudendnum, which are very transparent, Professor Van Beneden has observed the fluid containing globules mount from the base towards the summit for some instants, when the circulation seems to become suspended for a time ; but soon the globules begin to move in the opposite direction, descending from the summit towards the base; shortly after it again mounts as at first, and thus the circulation goes on alternately up and down. This movement of fluid in the stem Professor Van Beneden is disposed to attribute to ciliary action, although no cilia are discoverable by the microscope; still, without such mechanism, it is difficult to account for two distinct currents running in opposite directions in the interior of the same tube, which exhibits not the slightest trace of a septum between them.\nThere seem to be no organs specially appropriated to respiration.\nWith the exception of the genera Coryne and Hydractinia all the Tubularid\u00e6 are provided with an external tubular sheath, or polypary, which is thin and semitransparent ; its texture is corneous or pergamentaceous, and very flexible. The polypary of the genus Tubularia is generally described as being a simple tube without any ramifications ; this, however, is only true in the case of young individuals inhabiting isolated stems. In old specimens the polypary is ramified at its base, and is only straight and simple at its free extremity.\nReproduction.\u2014In all the genera of this family the reproductive organs consist of groups of little pedicles growing in the vicinity of the tentacula, which support little rounded bodies, often united together in bunches, which when mature fall off like fruit from a tree, and are dispersed to form new colonies. It is a true animal seed, which the waves carry to a distance and disseminate in all directions, and the whole observable reproductive apparatus consists of the organs that produce these rounded corpuscles or ova. Yet simple as\n* Phil. Trans, for 1834, pt. 2.\nthis arrangement of the reproductive system may appear, we learn from the researches of Professor Van Beneden that the propagation of the Tubulandce is effected by no fewer than five different modes ; namely,\n1.\tBy continuous gemmation.\n2.\tBy the production of free gemmae.\n3.\tBy simple ova.\n4.\tBy ova with a multiple vitellus.\n5.\tBy free gemmation and ova combined. Observation has moreover shown that in every species propagation is effected by more than one of these modes of reproduction, and sometimes by three or four ; and it must be remarked that in none of them is the cooperation of a male apparatus requisite, neither have any male organs or spermatozoa been as yet detected.\nFirst mode of propagation, by continuous gemmation. \u2014 This is the ordinary form of gemmiparous generation, whereby a colony is developed by sprouts derived from a single individual ; the appellation \u201c continuous gemmation,\u201d is applied to it by Professor Van Beneden, to distinguish it from the second mode of reproduction by free gemmae.\nThis method of propagation is the simplest possible, and is effected by mere growth from the original polype in certain determinate points of its substance, which points are similarly situated with respect to each other in all the individuals belonging to the same species. At these points gemm\u00e6 appear exactly similar both in texture and mode of growth to the body from which they spring ; and these buds as they grow give birth to others in a precisely similar manner. All these animals, be it remembered, are, like the Hydr\u00e6, capable of being reproduced by the mechanical division of their bodies, so that if one be cut into several fragments, each portion may give rise to a new individual ; every part of their structure is endowed with a reproductive power comparable to that which is conferred only upon the eggs of the superior animals ; whence we might almost be induced to regard the different cells composing their bodies as analogous to ova, and the polype itself as a mere aggregation of germs. It is upon the definite points whence these buds sprout that the particular characters of the Polyparies depend, else they would mostly resemble each other, for at their first production there is little difference to be observed between them.\nIn like manner when a stem is cut off transversely, a bud is developed from the cut extremity, which by its growth prolongs the original trunk. When this kind of gemma has attained to a sufficient size there arises from its extremity a little crown of tubercles, and subsequently a second becomes manifest at some distance from the first ; and as the growth of these tubercles continues, each of them becomes at length developed into a tentacle. The tentacle, therefore, grows from the body exactly in the same way as the bud from the stem, the only difference being that the former is solid, and the latter tubular.","page":42},{"file":"p0043.txt","language":"en","ocr_en":"POLYPIFEllA.\n4 3\ntaenia. They resemble numerous appendages disposed in a circle and forming a crown around the body of the polype. (Fig. 48, o.) These pedicles grow in the same manner as the buds and the tentacula described above, that is to say, a hollow tubercle first makes its appearance, which seems to be merely an extension of the external covering of the polype. Each tubercle slowly expands, and soon divides into one or more branches, which are all hollow, and the same fluid which circulates in the general substance of the polype may be observed to pass into their interior.\n* At the free extremity of each of the pedicles thus formed a distinct cell is soon perceptible, situated immediately beneath the surface, which cell is the rudiment of a new individual. (Fig. 49, l, a.) No nucleus has been remarked in its interior. This primitive cell, which might also be regarded as an egg or as an ovule, sometimes becomes organised internally, in which case the reproductive process assumes the third or the fourth form, subsequently to be noticed, or else it serves for the point of departure, or it might almost be said the mould for the formation of a free gemma, which becomes organised around it at the expense of the pedicle itself. It is in effect a part of the reproductive appendage that will subsequently become detached ; but at this period of its development it is impossible to determine after which of the four modes of reproduction the embryo will be formed. The vesicle (a) now increases rapidly in size, and beneath it another membrane is soon perceptible, which by its inner surface is in contact with the circulating fluid. This membrane is the origin of the new individual, or, in other words, a blastoderm, formed by the internal skin, and not by the vitellus. Soon there is seen, projecting from its centre,a little cone (fig. 49. 3, 4), which, compressing the vesicle (a), forms a depression upon its inner surface, and the vesicle now begins to assume the appearance of a serous membrane, yielding to the pressure of the organs over which it spreads, and ultimately covers, much in the same way as the pleura covers the lungs. The tubercle (b) will afterwards form the walls of the digestive cavity, and may be seen to have the circulating fluid derived from the body of the polype moving in its substance. Around the base of the cone (b) may now be seen four other tubercles (c, 4, et seq.), which become developed like the preceding; but, instead of compressing the vesicle (a), they surround it, and ultimately completely enclose it. They carry the skin with them, so as to have the appearance of a transparent vase* having four\nThe growth of the horny polypary exactly keeps pace with the development of the soft substance, and even goes beyond it. Below the tentacula the body soon becomes constricted, marking the boundary between it and the stem ; and soon the polype, becoming too large to be contained in its sheath, issues forth, and expanding its tentacula becomes perfectly unfolded. The oviferous pedicles, hereafter to be described, are developed subsequently.\nFig. 48.\nTubularia coronata, magnified.\na, stalk ; b, Avails of the polypary ; c, substance common to all the individuals, Avhereby they are brought into mutual organic communication; d, limit between the individual and the community ; g, the long tentacles ; h, the short tentacles ; k, collar formed by the tentacles ; o, ova ; n, a bud ; p, a bud further developed; q, a hud still further advanced, showing indications of the tAvo rows of tentacles (g, h). (After Van Beneden.)\nSecond mode of propagation, by free gemmae. \u2014The free gemmae are produced upon distinct pedicles, which in the genus Tubularia are developed within the lower circle of ten-","page":43},{"file":"p0044.txt","language":"en","ocr_en":"POLYPIFERA.\n44\nlongitudinal prominent bands, the free edge slightly enlarged and rounded, a pedicle in the middle like the stem of the vase, and the transparent vesicle lining its interior throughout.\nFig. 49.\nA series illustrating the development of Tubularia hy\nfree gemmae, from the first indication of the bud to\nthe time when it becomes detached.\n1.\tA hollow tubercle or elevation, in the interior of which a movement or circulation of the globules, indicated by the arrow, takes place; a, a cell just beneath the surface.\n2.\tThe same, showing the cell more advanced ; a, indicates this cell in all the figures.\n3.\tThis, and the following figures, represent the development of the gemma more and more advanced; b, a tubercle, situated beneath the cell, which becomes the stomach of the embryo; this organ is indicated by the same letter in the other figures.\n4.\tc, tubercles shooting up from the sides ; they are hollow, and communicate with the cavity of the stomach, and are the first indication of four vessels proceeding from the stomachal cavity. In the following figures the letter c indicates these vessels.\n5.\tb, the tubercle become more elevated, indenting the cell a ; the four secondary tubercles, c, more distinct and prominent.\n6.\tThe stomachal and its four surrounding hollow tubercles still further prolonged.\n7.\tIn this figure the four smaller tubercles have become vessels, and united with one another in front.\n8.\tThe four vessels have more completely united in front ; the arrows here, as in the other figures, indicate the current of the circulating fluid.\n9.\td, The first indications of the tentacles,\" consisting of tubercles sprouting from the four vessels.\n10.\tThe tubercles, d, at the end of the four vessels, c, have become sufficiently elevated to make a projection on the exterior.\n11.\tThese tubercles, become considerably salient externally, are now manifestly the four tentacles of the embryo.\n12.\tMinute cells are now visible at the extremity of the tentacles.\n13.\tThe tentacles still more advanced ; the line of separation of the embryo from its stalk become distinctly visible.\n14.\tHitherto the stomachal cul-de-sac has progressively increased,- it now begins to diminish, and the cell a, or the space between it and the external envelope becomes opened at e, forming a kind of mouth ; the embryo is now capable of great extension; the pedicle is constricted at the point of insertion and its internal cavity nearly obliterated.\n(From Van Beneden.')\nThe different phases of the development above described will, however, be best understood by a reference to the series of figures which we have appended, carefully copied from Professor Van Beneden\u2019s elaborate illustrations.\nThe joung Tubularia has now assumed the appearance of a Beroe, and in this condition has doubtless been often mistaken for an individual belonging to the class Acaleph\u00e6 ; and lively contractions of its body are frequently witnessed, although it still remains attached to its pedicle.\nAt the extremity of each of the four longitudinal vessels a little tubercle now becomes developed, which, as it becomes elongated, is converted into a tentacle, or sometimes, as in Eudendrium, by its bifurcation, two tentacula are formed from each tubercle.\nAt this period of its development the young Tubularia spontaneously detaches itself from the parent stem, presenting at the moment of its separation the appearance of a balloon, or rather of a melon. (Fig. 50.1,2,3.) Its contractions become more and more lively, and it is by the aid of these movements that its separation is effected. The two poles of its globular body may be seen to approach each other, and to separate alternately, with a movement of systole and diastole similar to what is observable in many Medusae. No traces of cilia are observable either externally or in the interior of its body. In this condition it presents an externai covering, which is, so to speak, merely a derivation from the integument of the parent polype : this covering presents somewhat more consistence than the internal parts, and is open in front.\nA second membrane lines the preceding throughout its whole extent ; like the former, it is quite transparent, and at the anterior opening (<?) is prolonged internally to a little distance, forming a sort of funnel. These walls enclose four vessels (e), which extend from the base of the embryo and open in front into the hollow zone (A), from which the tentacula take their origin. These longitudinal vessels therefore communicate with each other by a transverse canal, and at their origin open into the central or digestive cavity, which","page":44},{"file":"p0045.txt","language":"en","ocr_en":"POLYPIFERA.\n45\nwill, presently, be more particularly described. From this disposition it results that the contents of the stomach can pass as far as the extremities of these four vessels, and by means of the transverse canal can be transit. 50.\nA series illustrating the development of Tubularia ly free gemm\u0153, after the detachment of the embryo from its peduncle, in continuation of that in the preceding cut. The same letters indicate similar parts in all the figures in this and the preceding series.\nFig. 1. An embryo detached and moving in the water like a Medusa, seen in profile ; in addition to the four vessels, whose development is demonstrated in the foregoing series, eight other canals (/) are now perceptible ; these belong to the external envelope.\n2.\tThe same viewed obliquely, showing the situation of the mouth e ; h, the transverse canal which brings the four vessels into communication.\n3.\tThe same seen from below.\n4.\tThe four bands or vessels contracted a little, giving to the embryo a subquadrate outline ; viewed from below. The embryo is now no longer spherical, but flattened, as well as subquadrate.\n5.\tThe embryo viewed obliquely from above ; the superior and inferior parietes drawn together ; the stomach projecting through the mouth. It now presents the form of a Greek cross, owing to the great contraction of the longitudinal bands or vessels.\n6.\tThe embryo placed inverted with respect to Fig.\n1 ; the stomachal cul-de-sac, which becomes the body of the polype, completely protruded.\n7.\tAn ideal transitory figure.\n8.\tThe embryo become fixed. The internal row of tentacles beginning to protrude.\n9.\tThe same more advanced. The two rows of tentacles further developed.\nferred from one to the other. Professor Van Beneden observed a fluid containing globules moving in this direction in their interior. The communication between the longitudinal vessels and the stomachal cavity, and their intercommunication by means of transverse canals, is another arrangement exactly similar to what exists in the adult Medusae.\nThe outer membrane presents eight longitudinal canals, which are found to be filled with cellules, but in which no movement has been observed. It is to the presence of these longitudinal bands that the embryo in this stage of its development owes its resemblance to certain fruits, more particularly to a melon.\nFrom the anterior part proceed four appendages (d), which were still undeveloped at the period of the detachment of the young polype, but which insensibly unfold themselves. These are the tentacula. In the centre there projects a rounded opaque body (b), generally of a red or yellowish tinge, which is the stomach. This viscus communicates, as has been stated above, with the four longitudinal vessels, and is the only opaque part of the embryo. It opens in front by an orifice which constitutes the mouth ; the whole organ is eminently contractile, turning itself in all directions like the body of a Hydra, sometimes elongating itself like a worm, and at others shrinking so as to be almost imperceptible.\nIf the embryos examined in this condition be vigorous, their movements are very varied, and the forms that they assume extremely singular. The regular contractions above noticed are the most simple actions ; the two poles separate and approach each other alternately, whence results the progression of the little creature. But this contraction may be carried to a still higher degree: the rounded stomach in the middle of the embryo not only contracts itself in every direction, but it seems to turn itself in the middle of' its transparent envelope like a worm in search of a passage by which to get out ; and at length it pushes its free extremity through the opening in front of it, and elongates its body still more until","page":45},{"file":"p0046.txt","language":"en","ocr_en":"46\tPOLYPIFERA.\nthe two poles of the balloon becoming approximated, the whole embryo becomes somewhat disc-shaped, or the four vessels that communicate with the stomach (if vessels they really are), by moderately contracting, form as many depressions dividing the embryo into four lobes (fig. 50.5,6.), or by a more forcible contraction give it the appearance of a Greek cross, and all these changes of form may take place in a few seconds.\nObservations are wanting relative to the manner in which the free embryo is converted into the fixed Tuhulana ; for although Professor Van Beneden observed the latter at a very early period after they had become attached, he was unable to witness the changes that they undergo at the moment of becoming attached to some foreign body, and therefore gives a hypothetical outline of the forms through which he supposes them to pass (fig. 50.7) preparatory to their final establishment as young Tubulari\u00e6 (8, 9).\nFig. 51.\nA series showing the development of Tuhularia coro-nata from ova.\n1.\tA ramification or bud of the ovary. The common cavity continued into it as a cul-de-sac, beyond which is the ovum.\n2.\tThe ovum becomes much enlarged, and surrounding the cul-de-sac.\n3.\tThe cul-de-sac turned aside by gentle compression. Indentations on the ovum indicating the formation of tentacles.\n4.\tAn elevation (b) in the centre of the tentacles become perceptible, which afterwards forms the proboscis-like part of the animal.\n5.\tThe same compressed between two plates of glass.\n6.\tThe embryo after its escape from the ovisac, having as yet but one row of tentacles.\n7.\tThe young animal become fixed. The short tentacles beginning to project at the anterior prolongation or proboscis.\nThird mode of propagation, hy simple ova. \u2014 This mode of reproduction approximates the nearest to what occurs in the higher animals.\nCells are observed to become organised in the middle of a vesicle in the same manner as the vitelline cells, and to become converted into an embryo. In this case the vitelline cells become aggregated and modified, so as to give rise to a new individual, which is isolated from the commencement of its existence. The point of departure for the formation of the embryo is the same as in the preceding mode of development, and the reproductive vesicle has at first precisely the same structure as in the last case, but instead of preserving its transparency, this vesicle soon exhibits numerous cells, which render it more and more opaque, and give it more the appearance of a vitellus. In this case moreover there is a great difference in the relations which the red pedicle (fig. 49, 6) bears to the embryo. In the preceding mode of development this pedicle constitutes an integrant part of the newly formed being, forming, in fact, its stomach, but in the oviparous mode there is no organic connection between the one and the other, the vitellus being formed between the pedicle and the integument of the offset, and on pressing the latter between two plates of glass these structures readily separate without any laceration.\nAs the vitellus increases in size it becomes impacted between the integument and the pedicle, and its augmentation of size still increasing, the upper part of the pedicle becomes covered with it as with a hood, and at last almost entirely enveloped by it. At this period the margins of the vitellus become indented on that side nearest the pedicle, and the tubercles between the indentations soon show themselves to be the rudiments of ten-tacula. The tentacula become more and more elongated, the embryo separates itself slightly from the pedicle, and a protuberance (fig. 51. 4, h) is then perceived in the centre of the tentacular zone, which becomes the proper body of the polype, or rather forms the walls of its stomachal, cavity.\nThe walls of the bud, which has hitherto contained the embryo, now become ruptured, and it gains its liberty (fig. 51.6). In this condition it almost exactly resembles a young Hydra in its contracted state, and in fact both its body and its tentacula seem to have the same anatomical structure as those of that simply organised polype. Having attained to this condition its development proceeds rapidly, and it soon begins to assume the specific form of the Tubularia from which it sprung (fig. 51. 7).\nProf. Van Beneden likewise witnessed the same mode of propagation in Syncoryna pu-silla.\nFourth mode of propagation, hy ova with a multiple vitellus. \u2014 The fourth mode of reproduction observed by Professor Van Beneden to occur among the tubular polypes is extremely curious. In this form, as in that last described, the young individuals are developed from ova, and the first steps of the process are precisely similar. A bud is formed from the surface of the parent zoophyte, in","page":46},{"file":"p0047.txt","language":"en","ocr_en":"POLYPIFERA.\nthe interior of which may be observed a vesicle that soon becomes organised into numerous cells, which constitute the vitelline mass exactly as in the last case. But, arrived at this point, the vitelline mass becomes tu-berculated, assuming the appearance of a raspberry, and, instead of a single vitellus, it is found to be an agglomeration of several, each of which contains in its interior a Purkingean vesicle from which a young individual is produced, which is of a totally diff\u00e9rent form from its parent and covered with cilia, by the aid of which it swims freely about in search of a locality where to fix itself. This form of reproduction will, however, be more particularly noticed in describing the Sertularian Polypes.\nFifth mode, by free gemmation and ova combined. \u2014 This last form of the reproductive process is merely a combination of two of the preceding, propagation being effected by the development of a free gemma, in the interior of which there is formed a divided vitellus. In this case a free embryo becomes organised, and takes the form of a young Medusa, according to the second mode described above, in the interior of which is contained an ovum with a multiple vitellus, from which numerous ciliated embryos are produced, as in the Ser-tularia geniculata hereafter to be noticed.\nTubiporid\u0153. \u2014 The polypary of the Tubi-\nTubipora musica.\npora (fig. 52.)consists of several stages of cylindrical tubes placed parallel to each other, or very slightly diverging. These tubes are separated from each other by considerable intervals, but mutually support each other by the interposition of external horizontal plates formed of the same dense substance as themselves, by which they are united together, so that a mass of these tubes exhibits an arrangement something like that of the pipes in an organ ; whence the trivial name musica by which the species is distingu:shed. From the upper ends of these tubes the polypes are protruded, and being when alive of a bright grass green colour they contrast very beautifully with the rich crimson of the tubes they inhabit. The mouth* of the polype is suspended in the centre of the tube by means of the soft membrane : it is surrounded with eight tentacula, the margins of which are fringed with two or\n\"r * Anatomie du Tubipore musical par Mons. Lain ouroux. Zoologie de Quoy et Gaimard, Voyage de 1\u2019Uranie.\n47\nthree rows of fleshy papillae. Beneath the opening of the mouth is the stomachal saccu-lus, around which arise the eight ovigerous filaments. Those filaments near their origin are loose and floating, but lower down they become connected with the soft membrane (fig. 53. 1, 2, d), with which the tube is lined,\nFig. 53.\n13\t2\nTubipora musica.\n1, 2, longitudinal sections ; 3, portion of the polypary, showing the connecting stage.\na, membranous collar, continuous with the tube ; b, calcareous tube ; c, tentacles ; d, ovaries.\nthroughout its whole length, but gradually diminishing in thickness as they descend. These filaments are equivalent to the ovigerous tubes of the other Anthozoa; but the ova are here developed upon their external surface, to which they are attached by short pedicles.\nExtending between the roots of the tentacula of the polype and the margin of the tube is the membrane, which, in the retracted state of the animal, is drawn into the shape of a funnel, the mouth of the funnel being continuous with the extremity of the calcareous tube. The funnel-shaped membrane is in fact a continuation of the calcareous tube, from which it only differs in texture from the circumstance that the latter has become solidified by the interstitial deposition of calcareous matter in its substance, while the former still retains its softness and irritability.\nThe funnel-shaped membrane does not terminate suddenly upon the calcareous tube ; the latter, indeed, is a prolongation and product of it ; the calcareous substance is deposited in this gelatinous membrane in the same manner as phosphate of lime is deposited in the bones of very young subjects, changing its soft texture into hard and solid substance. The manner, therefore, in which this tube is formed cannot be compared to the mode of formation of the cells of Serpul\u00e6 or the tubes of Mollusca ; in the latter it is a secretion of the skin, almost an epidermic product. In polyparies, on the contrary, there is a real change of soft into solid substance, which is effected gradually, but the calcareous matter is not deposited in layers.","page":47},{"file":"p0048.txt","language":"en","ocr_en":"48\tPOLYPIFERA.\nWe do not doubt that all polyparies, whether flexible or calcareous, are formed in a similar manner, the horny matter of one and the calcareous axis of the other being entirely produced by the conversion of soft gelatinous matter into hard substance through the agency of the membrane which always invests the polypes. Moreover, this infundibular membrane must offer a thousand modifications of form in different families, genera, and even species. Sometimes it is very extensive and irritable ; at others, adhering to the parietes of the cells throughout their entire length ; the polype is immovably fixed at the opening of its tube. We consider this membrane as one of the most essential organs for the production of the polypary, having observed it in Flustr\u00e6, Sertulari\u00e6 ; and, as far as we know, the same is the case in Madreporigenous polypes.\nWhen the calcareous tube has grown to a certain height, the animal proceeds to form the external horizontal stage, by means of which it becomes united to the tubes in its vicinity. In order to effect this the soft infundibular membrane spreads itself out horizontally, so as to form by its duplicature a kind of rim round the margin of the tube (fig. 2, a) ; in this state it loses the irritability that it previously possessed, and its two opposed surfaces becoming united to each other, it is gradually solidified by the deposition of calcareous matter in its substance, so as to form a firm horizontal plate. It generally happens that several of the neighbouring polypes construct similar horizontal stages at the same time, and precisely upon the same plane, in which case all the stages coalesce at their circumference, and become so intimately conjoined as to form but a single floor, which, when calcified, exhibits no marks whatever of the union which has been thus effected. After the formation of this stage the growth of the tube again proceeds upwards, in the same manner as before, until it arrives at its full height.\nIt is difficult to say how the ova formed upon the ovigerous filaments make their escape ; for, seeing their size, it seems impossible for them to pass out by the mouth ; and it seems more probable that it is not until a polype dies that the germs of its progeny leave the tube of their parent, and settling down upon the horizontal stage constructed by the preceding generation commence their development.\nWhen first attached in this position the young Tubipore exhibits not the slightest trace of the future polype, but consists of a simple gelatinous membrane folded upon itself so as to resemble a little turban. This turban-shaped mass gradually elongates itself by its upper part, and, as its development proceeds, produces a polype in its interior, the tube which encloses it remaining soft and flexible above, while it is gradually calcified below. And it may here be remarked, that from the small diameter of the commencement of its tube, it is evident that the animal in*\ncreases in all its dimensions during its advance to maturity.\nSertularid\u0153.\u2014 The depths of the ocean are inhabited by innumerable zoophytes equally remarkable for the beauty of their appearance and the peculiarity of their structure ; these are the Sertulari\u00e6, whose arborescent stems have so much the appearance of vegetable productions that they are still regarded by the uninformed as \u201c sea-weeds.\u201d On putting a living specimen of a Sertularia (fig. 54)\nFig. 54.\nBranch of Sertularia geniculata, magnified, showing cells, polypes, and ovigerous vesicles.\ninto a jar of its native element, and watching it attentively with the aid of a magnifying glass, its real nature becomes at once apparent, and instead of being of vegetable origin, all the elegant ramifications of which it consists are found to be peopled with numbers of hydriform polypes, all actively employed in catching prey, and apparently ministering to the support of the general community formed by their aggregation.\nThe stem of a Sertularia consists of a hollow tube, composed of a flexible horny substance, diversely ramified in different species, in the interior of which is enclosed a soft animal substance, which constitutes the living portion of the zoophyte. At regular intervals every branch is studded with little cells, composed of the same horny material as the general stem, in each of which is lodged a Hydra, or at least a polype similar to the Hydra in its general characters, the base of which is continuous with the central living pith that","page":48},{"file":"p0049.txt","language":"en","ocr_en":"POLYPIFERA.\n49\npermeates the stem, which thus seems to be nourished by the hundreds of little polypes that are constantly fishing for food.\nAt certain periods of the year, besides the polype-bearing cells, other horny receptacles are developed, called the ovigerous vesicles {fig. 55, h), in which the ova are produced.\nThe ovigerous vesicles are differently disposed according to the species, sometimes arising from the branches of the coralline, at others from the'axillae formed by their subdivisions ; their shape likewise is very various, and sometimes they are covered with a little operculum, or lid, which closes the orifice of the vase-like vesicle during the maturation of the reproductive gemmules, and at last opens so as to permit their escape. These gemmu-liferous urns are, however, deciduous, and fall off after the development of the germs of reproduction is completed.\nSuch being the general structure of the Sertularid\u00e6, we must now proceed to examine more minutely their intimate organisation. The stem of the Sertularian is composed of two layers, of which the exterior {fig. 55, b),\nFig. 55.\nDiagram of Sertularian.\na, inner or nutritive layer ; b, outer or tegumentary layer ; c, oral tentacles of the polype ; d, e, gemmules ; f polypiform external capsule ; h, ovigerous cell.\nor tegumentary layer, is of a dense horny texture, while the internal, or nutritive layer {fig. 55, a), is of a soft pulpy character according to the pattern peculiar to the species ; the tegu-rnentary layer expands at appointed distances into the polype-cells {fig. 55, g) ; and it is from this layer likewise during the reproductive season that the ovigerous vesicles are developed. The nutritive layer (fig. 55, a), it will be seen, not only lines the stem, but likewise penetrates into the polype-cells, where it becomes continuous with the body of the con-\nVOL.IV.\ntained polype, the structure of which closely resembles that of the Hydra ; it seems, in fact, to consist of nothing but a stomachal sacculus, the mouth of which is surrounded with contractile tentacles, which are never, as erroneously stated by some writers, provided with vibratile cilia, such as are possessed by some more highly organised polypes. The nutriment elaborated in the digestive sacculi passes into the central cavity of the stem, in which an evident circulation of globules is apparent, somewhat analogous in its appearance to what is perceivable in the Char a and other transparent vegetables.\nIt is from the nutritive layer which lines the ovigerous vesicles likewise that the reproductive gemmules are developed. These (fig. 55, cl), as they gradually become separated from the nidus in which they are formed, retain their connection with the vital tissue of the nutritive layer, by the intervention of a kind of umbilical cord, until they are sufficiently matured to allow of their escape. When this period arrives each gemmule is found to be covered over with vibratile cilia, by the action of which it detaches itself from the umbilical filament, and, escaping from the reproductive cell, swims away into the surrounding element.\nHere, by means of its cilia, it swims about, having much the appearance of a polygastric animalcule, until it finds a fit locality for its development, when it settles down, and, losing its locomotive organs, spreads out like a film of jelly upon the supporting body. The formation of its horny envelope then begins, fibres of which are first extended like the spreading root of a tree, so as to give a firm hold upon the basis for support ; and then the stem itself begins to shoot upwards, developing, as it ascends, the nutritive polypes and the horny cells in which they are individually lodged.\nIn order to understand how growth is accomplished in these tube-clad zoophytes.it will be necessary to refer once more to the preceding diagram (fig. 55). The tegumentary layer of the zoophyte (fig. 55, b) is at first quite soft and expansible, the hard corneous matter by which it is consolidated being afterwards superadded to its texture. Whilst growth is in progress, therefore, this outer layer shoots upwards in conformity with the pattern to which it belongs ; but whilst the top of the tube retains its softness and power of growth it is continually fortified below by the deposition of the horny matter which gives it solidity : growth can therefore only proceed at the extremity of every branch where this layer remains capable of further development ; for no sooner is it solidified than it remains permanently unchangeable. Hence it is that these zoophytes differ so remarkably from plants in the character of their arborescence : in the latter the stem is increased by constant additions to its thickness, butin the case of the Sertularia no such thickening is possible ; so that both stem and branches retain the same diameter throughout, however much their\nE","page":49},{"file":"p0050.txt","language":"en","ocr_en":"50\nPOLYPIFERA.\nramifications may be extended. As the growth of the tegumentary layer thus proceeds in one direction only, except when the development of polype-cells calls for its lateral expansion, the nutritive layer within continues to grow pari passu, and from it the polypes are produced as the cells become ready to receive them.\nBryozoa (Ehrenberg), Ciliobrachiate Polypi (Farre),\u2014 The Bryozoa, although closely resembling some of the simpler Poly-pifera, described in the preceding pages, with which, indeed, until a very recent period, they were confounded by zoological writers, differ from them in so many essential points of their structure, that, but for the convenience of description, we should have preferred to regard them as a distinct class, exhibiting a much higher phase of organisation than any of the nudibrachiate races. In all the families of Polypifera we have as yet had occasion to examine, it will have been noticed that the tentacular apparatus around the mouth, although very generally pinnated, are quite devoid of cilia ; but in the Bryozoa one of the most obvious circumstances observable in their organisation is, that all the circumoral arms are crowded with vibratile organs, the play of which, when in action, is exceedingly energetic, producing rapid currents in the surrounding water, and thus hurrying towards the mouth of the animal whatever substances may come into the neighbourhood of the vortex so produced, and in this way securing an abundant supply of food, almost without exertion on the part of the creature itself. From this most conspicuous character, common to the entire group, Dr. Arthur Farre was induced to propose for them the name of Ciliobrachiata. It is in their internal economy, however, that their chief points of distinction are to be sought. Like the ordinary polypes, most of these little animals inhabit cells of different shapes and various degrees of density. These cells are sometimes calcareous and opaque, but in very many genera so thin and diaphanous that nothing is more easy than to examine, by means of the microscope, the anatomy of the animal within. When thus examined, the differences between a Bryozoon and an ordi-dinary polype become immediately manifest, and may be briefly stated as follows.\nIn the nudibrachiate polypes the stomach is a simple sacculus unprovided with any intestinal tube or anal orifice, so that after taking food the egesta are necessarily expelled through the oral opening ; but in the Ciliobrachiata, not only is the stomach found to be floating loosely in a visceral cavity, and of very complete structure when compared with the digestive sacculus common to the preceding tribes, but it terminates in a complete intestinal canal, provided with a distinct anal orifice, through which the faeces are discharged. Accompanying this advanced condition of the alimentary apparatus all the other systems assume a more elevated type of structure, as will be immediately apparent from the details\nof their anatomy, upon the consideration of which we are about to enter. Much, doubtless, yet remains to be made out in the economy of these animals ; still the researches of Ehrenberg* * * \u00a7, Milne Edwards, Audouinf, Thompson j, Farre \u00a7, and Van Beneden ||, have already put us in possession of most important information concerning them, which promises to open a yet wider field for discovery.\nThe cell of Bowerbankia {fig.56), as de-\nFig. 56.\nBowerbankia densa, magnified 80 diameters.\na,\tone of the animals fully expanded ; 1, pharynx ; 2, cardia ; 3, manducatory organ, or gizzard ; 4, stomach, its parietes studded with the hepatic follicles ; 5, pylorus ; 6, intestine, containing pellets of feculent matter ; 7, anus. The gastric (8) and tentacular (9) retractors are seen within the cavity of the body. The flexible portion of the cell, or the operculum, is seen expanded and surrounding the upper part of the body.\nb,\ta similar animal completely retracted. The stomach drawn to the bottom of the cell. The upper portion of the alimentary canal flexed. The tentacula somewhat distorted by the pressure of the operculum. Their retractor filaments (1) relaxed. The upper part of the cell is occupied by the operculum folded up in its axis, and from it the upper (2) and lower (3) sets of opercular retractors are\n* Symbol\u00e6 Physic\u00e6.\nf Annales des Sciences Naturelles, for Sept. 1828, and July 1836.\nt Zoological Researches, Mem. V., Cork, 1830.\n\u00a7 Phil. Trans, for 1837, part 2.\nJ R\u00e9cherches sur l\u2019Anatomie, la Physiologie et l\u2019Embryogenie des Bryozaires. 4to. Brussels, 1845.","page":50},{"file":"p0051.txt","language":"en","ocr_en":"POLYPIFERA.\t\u00d6l\nseen radiating, and in their contracted state. These filaments are about g J5_ inch diameter in this state.\nc,\tAn immature animal. The tentacula and alimentary canal rudely formed; the cavity in the latter very distinct. The tentacular and opercular retractors also shown ; 1, the gizzard.\nd,\tone of the gemm\u00e6 in its. earliest state. The cavity just defined, but no animal distinguishable. (After Farre.')\nscribed by Dr. Arthur Farre, is cylindrical, and closely embraces the body of the animal ; it is of a firm unyielding consistence in the lower two-thirds of its extent, but terminates above by a flexible portion, which serves to protect the upper part of the body when the whole is expanded, in which state it is of the same diameter as the rest of the cell ; but when the animal retracts, this portion is folded up and drawn in after it, so as to close its mouth. The flexible part consists of two portions, the lower half being a simple continuation of the rest of the cell, the upper consisting of a row of delicate bristle-shaped processes, or setae, which are arranged parallel with each other round the top of the cell, and are prevented from separating beyond a certain distance by a membrane of excessive tenuity which surrounds and connects the whole. This arrangement is common to all the species possessing a cylindrical cell ; but the length of the setae is very variable ; indeed they are sometimes so stunted in their development that their presence is hardly recognisable.\nThe cells of the Flustr\u0153 and Eschcir\u0153 are disposed side by side upon the same plane, so as to form a broad leaf-like polypary, which is in the former genus of a coriaceous or horny texture, but in the latter so completely calcified as to resemble the skeletons of the Litho-phytous Polypes. The individual cells (y%. 59), which are so extremely minute that they\nFig. 57.\nF schar a cervicomis, natural size. (After Milne Edwards.')\nrequire a microscope for their examination, vary,in shape in different species, and generally have their orifices defended by projecting spines, or sometimes by a movable operculum or lid, which answers the same purpose\nas the setae of Boicerbankia, by closing the entrance during the retracted state of the animal. The growth of these polyparies, which are thus densely populated, is effected by the progressive addition of new cells around the circumference, those occupying the margin being of course the most recently formed, and, indeed, the latter are not unfre-quently found inhabited by the living animals, whilst in the older or central ones the original occupants have perished.\nFig. 58.\nA polype of Eschara cervicomis highly magnified.\no, tentacula ; h, first digestive cavity, which seems to he analogous to the respiratory cavity of the compound ascidians ; c, filaments arising from the part of the alimentary canal immediately below this cavity ; d, stomach ; e, intestine ; /, anus ; g, retractor muscles. (After Milne Edwards.)\nThe facts observed by Dr. Milne Edwards * relative to the mode of formation of these cells possess a high degree of interest, and materially support the views already given concerning the organised nature of the skeletons of zoophytes in general; proving that the calcareous matter to which their hardness is owing is not a mere exudation from the surface of the animal, but is deposited in the meshes of an organised tegumentary membrane, from which it can be removed with facility by means of extremely dilute muriatic acid. When so treated a brisk effervescence is produced, the cells become flexible, and are easily separated from each other; but they are not altered in form, and evidently consist of a dense and thick membrane, forming a sac, in which the digestive organs of the animal are contained. In this state the opening of the cell has no longer a defined margin, as it seemed to have before ; but, as in the case of the Tubipora musica, described, in a preceding page, the membranous cell is found to be continuous with the tentacular sheath. We see, therefore, that in these creatures the shell is an integrant portion of the animal itself, not a mere calcareous crust moulded upon the surface of its body, being, in fact, a\n* R\u00e9cherches anatomiques,\" zoologiques, et physiologiques sur les Eschares; An.-des Sc. .Nat. ror","page":51},{"file":"p0052.txt","language":"en","ocr_en":"52\tPOLYPIFERA.\nportion of the tegumentary membrane, which, by the molecular deposit of earthy matter in its tissue, becomes ossified, something like the cartilage of the higher animals, without ceasing to be the seat of nutritive movement. It is evident likewise that what is usually called the body of the Bryozoon constitutes, in fact, but a small portion of it, principally consisting of the digestive apparatus.\nAs to the operculum, destined to close the entrance of the tegumentary cell, it is merely a lip-like fold of the skin, the marginal portion of which acquires a dense consistency by interstitial deposit, while at the point where it is continuous with the general envelope it remains sufficiently soft and flexible to form a sort of hinge.\nThe tegumentary sac, deprived of its carbonate of lime, seems to be formed of a to-mentous membrane, covered, especially upon its inner side, with a multitude of cylindrical filaments, disposed perpendicularly to its surface, and closely crowded together. It is in the interstices left by these fibres that the calcareous matter appears to be deposited; for if a transverse section be examined with the microscope the external wall is seen not to be made up of superposed layers, but of cylinders and irregular prisms arranged perpendicularly to the axis of the body.\nBut the above are not the only arguments adduced by Milne Edwards in proof that these polyparies are maintained in vital connection with the animal. On examining the cells at different ages it is found that after they are completely calcified they undergo material changes of form.\nThis examination is easily made, seeing that in many species the young sprout from the sides of those first formed, and do not separate from their parents ; each skeleton, therefore, presents a long series of generations linked to each other, and in each portion of the series the relative ages of the individuals are indicated by the position which they occupy. It is sufficient, therefore, to compare the cells situated at the base, those of the middle portion, those of the young branches, and those placed at the very extremities of the latter. When examined in this manner it is seen that not only does the general configuration of the cells change with age, but also that these changes are principally produced upon the external surface. For instance, in the young cells of Eschara cervicornis, the subject of these observations, the walls of which are of a stony hardness, the external surface is much inflated, so that the cells are very distinct and the borders of their apertures prominent ; but by the progress of age their appearance changes, their free surface rises so as to extend beyond the level of the borders of the cell, and defaces the deep impressions which marked their respective limits. It results that the cells cease to be distinct, and the polypary presents the appearance of a stony mass, in which the apertures of the cells only are visible.\nFig. 59.\nPortion of a branch of the polypary of Eschara cervicornis, magnified 20 diameters to show the form and\narrangement of cells. (After Milne Edwards.)\nMuscular system.\u2014The muscular system of Bowerbankia is described as follows.\nFor the process of retraction two distinct sets of muscles are provided ; the one acting upon the animal, the other upon the flexible part of the cell.\nThe muscles for the retraction of the animal are contained in the visceral cavity, and consist of two bundles of delicate thread-like chords {fig. 56, 8 and 9) ; the one set, arising from the bottom of the cell, to be inserted about the base of the stomach ; the other, also arising from near the bottom of the cel), though generally at the opposite side from the former, and passing up free by the side of the pharynx, to be inserted around the line of junction of this organ with the base of the tentacula. The muscles provided for the retraction of the operculum, or flexible portion of the cell, have their origin from the inner surface and near the top of the stiff part, and are inserted into the flexible portion on which they act. They are most distinctly seen when the flexible operculum is completely drawn in, at which time the latter is folded up so as to occupy the axis of the upper part of the cell, and to it the muscles are seen extending from the opposite sides of the cell from which they have their origin. They consist of six flattened bundles of fibres, having a triradiate arrangement. The upper three sets {fig. 60, a, 3) act upon the upper part of the cell, and are inserted into it. The lower three {fig. 60, o, 4) are smaller, and are for the purpose of retracting the bundle of setae with which it is crowned.\nThese fasciculi afforded Dr. Farre an excellent opportunity for investigating the structure of this form of muscle. It would appear as if muscular fibre were reduced to its simplest condition. The filaments are totally disconnected, and are arranged the one above the other in a single series. They pass straight and parallel from their origin to their insertion, and have a uniform diameter through their whole course, except that each filament generally presents a small knot upon its centre, which is most apparent when in a state of contraction, at which time the whole filament also is obviously thicker than when relaxed.","page":52},{"file":"p0053.txt","language":"en","ocr_en":"POLYPIFERA.\t53\nThe filaments have a watery transparency and smooth surface, and under the highest powers of the microscope present neither an appearance of cross-markings, nor of a linear arrangement of globules. These muscles, though apparently attached to the inner walls of the cell, must yet have the membranous parietes of the body interposed between their insertions and these walls. In the lower part the integument is only occasionally seen separate from the walls of the cell, but above it may be easily discerned in the expanded animal, passing up to be inserted around the tentacular ring, and thus distinctly bounding this part of the body, which is always free within the expanded operculum.\nThe operation of this mechanism in retracting the animal within its cell is as follows. The tentacula, from being expanded in the form of an inverted cone, are brought together into a straight line, and immediately begin to descend (fig. 60, d). Their descent is\njFig. 60.\nBowerbankia densely magnified 80 diameters. A series to show the mode in which the operculum and upper part of the body is unfolded. The same animal is represented in four different stages.\na.\tFirst stage: the top of the cell completely closed ; the set\u00e6 folded up in the centre (1), with the flexible portion of the cell (2) inverted and closely surrounding them ; the muscles contracted (3, 4.)\nb.\tSecond stage: the bundle of the set\u00e6 (1) rising from the centre of the cell being forced upward by the pressure of the tentacula ; the flexible portion (2) rolling from around the set\u00e6, and the muscles (3) put upon the stretch.\nc.\tThird stage : the flexible portion (2) completely everted; the set\u00e6 (1) still lying together; the tentacles just appearing between them.\nd.\tFourth stage : the tentacula appearing above the margin of the operculum; the integument of the body, which forms the tentacular sheath, half everted (3) ; the operculum completely expanded. (These stages are taken arbitrarily, the process being continuous.) The animal is shown completely extended at fig. 56, a. (After Farre.')\neffected by the contraction of the muscle (fig. 56. 9) which passes from the base of the cell to the tentacular ring, whilst at the same time the stomach is drawn down by its retractor (fig. 56. 8). The whole body, however, does not descend in a mass, but must be folded up in a somewhat complicated manner, in order that the cell may completely enclose\nit. For this purpose the cesophagus surmounted by the tentacula descends first, whilst the integument of the upper part of the body begins to be inverted at the point where it has its insertion around the tentacular ring. As the descent of the tentacula proceeds, the inversion of the integument continues forming a sheath around them (fig. 60, c), until the extremities of the arms have descended to a level with the top of the unyielding portion of the cell. The animal is now drawn completely in, the stomach brought close to the bottom of the cell, and the oesophagus bent in the form of the letter S ; the tentacula lying straight in the axis of the cell, enclosed in their tegumentary sheath, and so separated from the fluid in the general visceral cavity, the centre of which they have the appearance of occupying, while in fact they are external to it. The animal being thus retracted, the next step of the process is to draw in the upper part of the cell after it. This process, however, always commences before the retraction of the body is completed, and by the time that the ends of the arms are on a level with the base of the setae, the latter are brought together in a bundle, and begin to descend apparently by the action of the lower of the two sets of opercular retractors above described. Their descent, like that of the tentacles, takes place exactly in the axis of the upper part of the cell, and is accompanied by an inversion around them of its flexible portion, similar to that of the integument of the body around the tentacula during their descent (fig. 60, b). Whilst the lower set of muscles are drawing down the set\u00e6, the upper set complete the retraction of the flexible part, and the whole operculum is thus packed closely in the upper part of the cell, the end of which now presents a triangular indentation, corresponding with the triangular arrangement of the opercular retractors (fig. 60, a). Thus the whole process of retraction may be easily accounted for, and the office of each set of muscles satisfactorily explained ; but the protrusion of the animal is effected by a totally different mechanism, viz., by the action of a set of transverse muscles acting upon the lining membrane of the cell, so as by their contraction to diminish considerably the diameter of the visceral cavity, and consequently exercise a pressure upon the fluid which it contains. The effect of this will be to elongate the body in the direction in which it is most free to move ; but Dr. Farre supposes that the act of protrusion is materially assisted by the cooperation of the alimentary canal, which undoubtedly has the power of straightening itself from the sigmoid flexure into which it is thrown when the animal is retracted ; and that this is the case appears the more probable, when we reflect that in the case of the simple hydriform polypes the advance and receding of the animal in its cell is entirely effected by the action of the parietes of the body, which are analogous to the alimentary canal in the present case, the hydriform po-\ne 3","page":53},{"file":"p0054.txt","language":"en","ocr_en":"54-\nPOLYPIFERA.\nlypes possessing no distinct muscles to assist in these operations.\nIn some species ofBryozoa there are only two sets of opercular muscles, whilst in others one set only is perceptible.\nAlimentary system. \u2014 In Bowerbankia the whole alimentary apparatus has been minutely described and figured by Dr. Farre.* The ten-tacula are united together at their base to form a circle, in the centre of which is the mouth, and from which descends the oesophagus, bulging a little at its commencement, and then contracting and passing down nearly straight to its termination. The parietes of the oesophagus, especially at the upper part, which may be more correctly denominated the pharynx {fig. 56, a, 1), are thickly studded with minute oval spots, arranged closely in contact with each other. The whole organ appears to be highly irritable, and contracts vigorously when food is introduced into it.\nAt the termination of the oesophagus is a small distinct cardiac orifice (fig. 56, a, 2) opening into a small globular cavity (3), of singular construction, that appears to perform the office of a gizzard, the parietes of which are thicker than any other part of the alimentary canal. This gizzard contains two dark round bodies, placed opposite to each other, from each of which dark lines are seen radiating. In the space between these two dark bodies may be seen a number of squami-form spots, arranged closely in contact, and presenting a beautifully regular tesselated appearance, which, on minute examination, is found to consist of a pavement of gastric teeth.\nThe gizzard opens downwards into the true digestive stomach (4), an oblong cavity terminating below in a blunt extremity. The entire walls of the stomach are thickly studded with spots of a rich brown colour. These appear to be hepatic follicles, and to prepare a fluid that tinges the whole organ, as well as its contents, of a rich brown hue.\nFrom the upper part of the stomach, and by the side of the entrance from the gizzard, arises the intestine (6) by a distinct pyloric orifice (5) that is surrounded by vibrating cilia. The intestine is narrow, and passes up straight by the side of the \u0153sophages, from which it is entirely separate and free, and terminates by a distinct anal orifice in the delicate parietes of the body, close to the outer side of the tentacular ring. The pari-etesof the intestine are marked with pale spots, and, like those of the whole of the alimentary canal, possess a high retractile power. The animal, when in full vigour, is seen projecting from its cell with the arms extended and the cilia in active operation, the upper part of the body being frequently turned from side to side over the edge of the cell, the extremity of which, from its peculiar flexibility, moves with it. The particles carried to the mouth by the action of the cilia, after remaining a\n* Loc. cit.\nlittle while in the pharynx, are swallowed by a vigorous contraction of its parietes, and carried rapidly down the oesophagus and through the cardia into the gizzard, which expands to receive them. Here they are submitted to a kind of crushing process, the parietes of the organ contracting firmly upon them, and the two dark bodies being brought into apposition. Their residence, however, in this cavity is only momentary, and they are immediately propelled into the true stomach below, where they become mixed with its contents, which, during digestion, are always of a rich brown colour, being tinged with the secretion of its parietal follicles.\nThe food appears to be retained for a considerable time in the stomach, and may be seen to be frequently regurgitated into the gizzard, whence, after having been again submitted to its operations, it is returned to the stomach. Here it is rolled about by the contractions of its parietes, and at its upper part is frequently submitted to a rotating motion. This rotation of particles is chiefly near the pyloric orifice, and a mass may be often seen projecting through the pylorus into the intestine, and rotating rapidly in the direction of the axis of the orifice. This rotation is effected by the action of cilia surrounding the pyloric orifice, which, in very transparent specimens, are distinctly visible with high powers of the microscope.\nThe granular matter, after rotating for some time at the pylorus (a provision for preventing its too rapid escape from the stomach), passes into the intestine, where it accumulates in little pellets that distend the parietes of the tube, and it is possible that it may here be still further acted upon by these parietes which have a spotted appearance.\nBy the contraction of the intestine the little pellets of excrementitious matter are carried rapidly upwards to the anal orifice, which is seen to open and the little pellet to be tilted over its edge, when it is immediately whirled away from the sight in the current produced by the ciliated tentacles, and the orifice of the tube again contracts.\nThe general character of the alimentary canal appears to be similar in all the Gilio-brachiate polypes, but in many genera the gizzard does not exist.\nThe anatomy of the animals inhabiting the cells of Flustr\u0153 and Eschar\u00e6 differs in some particulars from that of Bowerbankia. In these, the crown of ciliated tentacula is inserted into the extremity of a kind of proboscis, which is itself enclosed in a cylindrical retractile sheath. From the margin of the opening of the cell arises a membrane equalling in length the contracted tentacles, and serving to enclose them when the animal retires into its abode. The tentacula when thus retracted, as was the case in Bowerbankia, are not bent upon themselves, but are perfectly straight and united into a fasciculus, the length of which, however, is much less than that of the same organs when expanded.","page":54},{"file":"p0055.txt","language":"en","ocr_en":"POLYPIFERA.\t55\nBy the opposite extremity to that which is derived from the margin of the cell, the tentacular sheath unites with a tolerably capacious tube, the walls of which are exceedingly soft and delicate, and near the point of their union we may perceive a fasciculus of fibres running downwards to be inserted upon the lateral walls of the cell. These fibres appear to be striated transversely, and are evidently muscular ; their use cannot be doubted. When the animal wishes to expand itself, the membranous sheath above referred to becomes rolled outward, everting itself like the finger of a glove as the tentacles advance. The muscular fasciculi are thus placed between the everted sheath and the alimentary canal, and by their contraction they must necessarily retract the whole within the cell.\nThe first portion of the alimentary canal {fig. 53,5) is inflated, and much wider than the rest ; it forms a kind of chamber, in which the water set in motion by the cilia of the tentacles appears to circulate freely. The walls of this chamber are exceedingly delicate ; the soft membrane forming them is puckered, and appears traversed by many longitudinal canals united by minute transverse vessels ; this appearance, however, may be deceptive.\nBeneath the first enlargement, the digestive apparatus becomes narrower, but immediately expands again, and offers at this point a certain number of filiform appendages (c), which appear to be free and floating in the interior of the cell. To the second cavity succeeds a narrow canal opening into a third dilatation, generally of a spherical form (d). From the last-named viscus issues a kind of intestine, which soon bends upon itself and becomes attached to an organ of a soft and membranous texture, having the appearance of a c\u00e6cum, and which seems to be continuous superiorly with the digestive tube. The latter continues its progress towards the upper part of the cell, and ultimately terminates by a distinct anal aperture upon the upper aspect of the tentacular sheath. The operculum which closes the cell in Flustr\u00e6 and Eschar\u00e6 is moved by two muscular fasciculi inserted into the internal face of this valve by the intermedium of two filaments analogous to tendons ; by their inferior extremity these muscles are attached to the walls of the cell, and when, by its own elasticity, the operculum is turned back, and the mouth of the cell thus opened, they by their contraction can close it like a door.\nReproduction. \u2014 The first mode of reproduction observed in the Ciliobrachiate polypes is by a process of gemmation: from the common stock or creeping stem upon which the animals grow. This is easily witnessed, as the gemm\u00e6 are met with in every progressive stage of development upon the same specimen, as represented in fig. 65.\nThe smallest gemm\u00e6 are described by Dr. Farre as homogeneous in their texture, forming little nodules on the parent stemu Those further advanced were seen to present something like a boundary line, indicating the\nthickness of the parietes of the future cell. Within this, in others, was a dark mass, which in larger ones presented a rough outline of the form of the complete animal. Those about half grown had all the parts distinctly traced out ; the retractor muscles completely formed ; the tentacles short and clumsy ; the walls of the alimentary canal thick, and its boundaries clearly defined.\nThis mode of propagation has been still more completely studied by Professor Van Beneden, whose opportunities of observation enabled him to prosecute the inquiry more closely.\nIn Pedicellina the phenomena attending the gemmiparous mode of reproduction are described by Professor Van Beneden as present-ing the following phases of development. First, there sprouts from the common stem of the Bryozoon, without any determinate situation, a tubercle which is but a prolongation from the stem itself {fig. 65, a, 8) ; this tubercle extends outwards, becomes more prominent, and soon swells out into a vesicle (5, 8), which is\" the first appearance of the new individual. Up to this period the interior of this vesicle, is like that of the stem itself, of which it is only an extension ; but now a cellule becomes visible in its centre, which forms the point of departure whence the development of the embryo proceeds.\nAround this primitive cell a series of other very small cellules soon group themselves, which seem to constitute the parietes of the primitive vesicle or the blastoderm, the original cell representing the vitelline cavity. The bud enlarges, and as its growth proceeds the internal tissue becomes thickened, so as to fill it ; subsequently an indentation is apparent on each side of the little cavity which separates it into two halves, the inferior of which will form the stomach, properly so called, while the upper division will become the anterior space between the tentacula.\nThe mode of reproduction by gemm\u00e6 has been carefully studied in the genus Laguncula {Lagenella of Farre) by the same investigator. The reproductive buds sprout from the creeping stems {fig. 61, y) which connect the individual animals, appearing at first as a slight prominence, that soon expands into a rounded tubercle, which is the commencement of a new cell.\nOn close inspection, this bud is found to consist of a transparent envelope, which is, in fact, a continuation of the general investment of the polype. This rudimentary cell is lined throughout with a soft membrane, having its inner surface studded with minute globules, by the accumulation of which the polype is ultimately formed. The bud itself is hollow, and communicates with the parent stem. It therefore has nothing in its composition resembling that of an egg ; neither distinct vesicle nor vitellus ; this condition of the gemma is represented in fig. 62. 1. The new-formed cell soon grows taller, and its lining membrane becomes thicker, and indicates the commencement of the intestinal canal, which is at first a simple cavity, bounded by the","page":55},{"file":"p0056.txt","language":"en","ocr_en":"TOLYPIFERA.\n56\nthickened lining membrane of the cell. This cavity once formed, the development of the different organs proceeds rapidly. First, in the middle of the cavity there appears a longitudinal fold resembling two lips (fig. 62. 2), which, as they approach each other, divide the cavity of the body into an anterior and a posterior compartment. The two lips, which\nhave a valvular appearance, become indented very regularly along their margins, and are soon recognisable as the rudiments of the tentacular circle (fig. 62 3).\nAt this epoch, it must be remarked, the polype presents two cavities distinct from each other. There is a space between the walls of the body and the parietes of the\nLaguneula repens, magnified 400 diameters.\nA. The animal completely retracted into its cell ; B> another individual completely expanded ; C, the outlines of another individual retracted. The same letters apply to each of the figures. The various viscera are situated in different planes, but are here represented all in the same.\na, the tentacles, protruded and expanded in B. ; the arrow indicates the set of the currents caused by the vibration of the cilia; b, buccal cavity; c, valve separating this cavity from the oesophagus ; d, oesophagus ; /, pyloric valve ; g, cilia, producing the rotation of the food in the stomach ; h, thickness\nof the parietes of the stomach ; i, intestine ; k, excrement contained in its interior ; l, anus ; m, testicle ; n, ovary ; o, ovum escaped from the ovary ; p, apertures through which the eggs are expelled, with an ovum in the act of escaping, q, spermatozoa, freed from the testicle, and floating in the fluid that surrounds the digestive canal ; r, s, t, u, v, muscles, retractors of the parts to which they are attached ; w, principal retractor muscle ; .r, transverse folds of the collar ; y, bands, perhaps muscular, of the collar ; \u00ab*, nervous oesophageal ganglion ; /?, stalk ; <y, a young buch (After Van Beneden.)","page":56},{"file":"p0057.txt","language":"en","ocr_en":"POLYPIFERA.\n57\nfuture alimentary canal, the interspace being in communication with the stem of the parent polype, and filled with a fluid that is analogous to the blood of the higher animals ; superiorly this cavity likewise penetrates into the tentacles, and the fluid which bathes the exterior of the alimentary canal thus finds admission even to the extremities of those organs (fig- 62. 6, m).\nFig. 62.\nDevelopment by buds of Laguncula repens.\n1.\tA young bud, with the cavity of the stalk extending into it, the parietes thickened at one part ; it is from this part that the intestinal canal and tentacles are formed.\n2.\tA sac is formed in the interior, having a longitudinal fold, which afterwards becomes the tentacles.\n3.\tThe rudiments of the tentacles are here apparent : the view is taken so that the space which they surround is visible.\n4.\tIn this figure all the organs of the animal can be distinguished, but the bud is not yet opened.\n5.\tHere the cell is opened, and the animal is ready to expand itself.\n6.\tSection of the adult animal ; a, tentacles ; b, mouth ; c, buccal cavity ; d, valve separating this cavity from the oesophagus ; e, oesophagus ; f stomach; g, pyloric cilia; h, pyloric valve; i, intestine ; k, anus ; l, peri-intestinal cavity ; m, communication of this cavity with the interior of the tentacles; n, nervous ganglion; o, long retractor muscle ; \u00bb, retractor of the stomach ; q, walls of the cell. (After Van Beneden.')\nThe second cavity, which is the intestinal, has as yet no communication with the external world. As the formation of the ten-tacula proceeds, the portion which is situated in front of them will become the sheath, and the other part the proper intestinal canal; the former cavity is, therefore, in all respects comparable to that which exists in the Tuni-cata situated in front of the proper oral orifice and lined with the branchial vessels. The tentacles of these polypes, in fact, if connected by transverse canals and attached to the sheath, would transform the animals in this phasis of their growth into Ascidians.\nAs the tentacula are formed by the prolongation of the tubercles which were their\nfirst rudiments, the cavity of the stomach and the rest of the intestinal tube gradually become apparent, and at the same time some globules are visible disposed around the cul-de-sac of the former viscus, which gradually become arranged into fibrill\u00e6, and constitute the retractor muscles.\nAt what time the nervous system is formed could not be detected.\nWhen the cell has nearly reached its full development, the tentacular sheath is completed in the same proportion, the parietes of the cell become softened, and an opening is formed which brings the young polype into communication with the surrounding element. The Bryozoon has now attained its full development, and can expand its tentacula, but as yet there are no traces of the reproductive organs, which seem to be formed after all the others.\nIn Halodaclylus reproduction by gemmation is effected by the development of young animals and cells amongst the mature ones. The newly formed cells are triangular, and the animal looks like a mere spot in their centre. As they grow they thrust aside the surrounding cells, and the number of their sides increases until they acquire the regular hexagonal form of the adult.\nThe Halodactylus likewise afforded Dr. Farre an opportunity of witnessing the second mode of reproduction common to the Bryozoa, namely, by the development of ciliated gemmules. These are readily seen in Spring as minute whitish points situated just below the surface of the mass {fig. 64, a). Sometimes\nFig. 63.\nThin transverse section of Halodactylus diaphonus. The centre occupied by cellular tissue and water. The circumference formed by cells in close apposition. The brown bodies scattered through the substance.\na, a, position of the gemmules, enclosed in the sac ; b, one of the gemmules escaped during the section into the central tissue, (fifter Farre.')\nthey are of a darker colour, and exceedingly numerous, appearing to occupy almost its whole substance. If one of these points be carefully turned out with a needle, it is found","page":57},{"file":"p0058.txt","language":"en","ocr_en":"POLYPIFERA.\nto consist of a transparent sac, in which are contained generally from four to six of the gemmules, which, as soon as the sac is torn, escape, and swim about with the greatest activity, affording a most interesting subject for microscopic investigation.\nWhen viewed with a power of 40, linear measure, they are seen to be of an oval or rounded form (fig- 63, b), convex above and\nFig. 64.\nHalodactylus diaphanus, a gemmule seen from above;\nthe cilia as when slowly acting round the margin in\nwaves. (After Farre.)\nnearly plane below, and fringed at the margin with a single row of cilia, which appear to vibrate in succession around the whole circumference.\nUnder an amplification of 120 they assume a different aspect {fig. 64), and their minute structure is clearly discerned. Viewed as opaque objects, both the body and cilia have a silvery whiteness, but by transmitted light the former appears of a dark brown, and the cilia of a golden yellow colour. Upon the most convex part of the body, which is not generally in the centre, but leaning to one side, are set from three to five transparent bosses, surrounded by a circle, and other circles are seen extending to the base of the body, which is bounded by a row of prominent tubercles. These marginal tubercles are from thirty to forty in number ; and from the circumstance of the cilia arising from them, Ur. Farre considers it probable that they are for the purpose of governing their motions, and therefore analogous to the muscular lobes of Hydatina senta and other Rotifera figured by Ehrenberg. No structure, however, could be detected in these, nor in any other part of the body, beyond a mere granular parenchyma. When thus highly magnified, it is seen that what examined with a lower power appeared to be a single cilium is, in fact, a wave of cilia, and that their motion, instead of being in the direction of the circumference of the disc, is at right angles to it. The ciliary phenomena are the most readily observed when the gemmule is nearly at rest, or has become languid ; it then lies either with the convex or the concave side uppermost, and with the cilia, which are of great length, doubled in the middle upon themselves, so that their extremities are brought back nearly to touch the margin of the disc from which they arise. The whole fringe of cilia is then suddenly unfolded, and after waving up and\ndown with a fanning motion, they are either again folded up towards the under surface of the body, or they commence their peculiar action.\nAs the cilia have the appearance of moving in waves round the disc (fig. 64), each wave may be thus analysed. From a dozen to twenty cilia are concerned in the production of each apparent wave, the highest point of which is formed by a cilium extended to its full length, and the lowest point between every two waves by one folded down completely upon itself, the intervening space being completed by others in every degree of extension, so as to present something of the outline of a cone.\nAs, however, the persistence of each cilium in any one of these positions is only of the shortest possible duration, and each takes up in regular succession the action of the adjoining one, so that cilium, which by being completely folded up formed the lowest between any two waves, now in its turn, by its complete extension, forms the highest point of a wave ; and thus, while the cilia are alternately bending and unbending themselves each in regular succession after the other, the waves only travel onwards, whilst the cilia never change their position in this direction, having, in fact, no lateral motion. When the waves travel very rapidly, they appear smooth on one side and fringed on the other. The whole of the ciliary motions are so evidently under the control of the animal, as to leave no doubt on this point. The whole fringe of cilia may be instantly set in motion, and as instantaneously stopped, and their action regulated to every degree of rapidity. Sometimes one or two only of the waves are seen continuing their action, while the remainder are at rest, or isolated cilia may be observed slowly bending and unbending themselves, or projecting entirely at rest. The body is generally pointed towards one extremity of the oval, and at this part may be observed a bundle of cilia longer than the rest, and moving very rapidly. Their vibrations were in several instances counted very evenly at 230 a minute, continuing in action when all the others were folded up. These Dr. Farre thinks may be .respiratory whilst the others are chiefly loco-motive. Dr. Farre thinks there can be little doubt that this explanation of the action of the cilia in the gemmules is applicable likewise to those of the tentacula of the adult animal, and not only in the Hylodactylus, but throughout the class generally; for he observed that the tentacular cilia are infinitely more numerous when at rest than they appear to be when in motion, and also that they vibrate, not in the direction of the plane of the arms, but at right angles to it, and with the same hook-like form as in the gemmules. In this way the apparent travelling of the cilia up one side of the arm and down the other, as the eye is seduced to follow the waves which they seem to produce, is at once explained.\nIt would be impossible to account for the","page":58},{"file":"p0059.txt","language":"en","ocr_en":"POLYPIFERA.\n59\nvariety of motions which the gemmules are capable of executing, were it not obvious how complete is their control over the action of the cilia, which are their sole locomotive organs. They generally swim with the convex part forwards, and with the greatest rapidity. Sometimes they simply rotate upon their axis or they tumble over and over, or, selecting a fixed point, they whirl round it in rapid circles, carrying every loose particle after them. Others creep along the bottom of the watch-glass upon one end with a waddling gait ; but generally, after a few hours, all motion ceases, and they are found to have attached themselves to the bottom of the glass. At the expiration of forty-eight hours the rudi-\nments of a cell were observed extending beyond the margin of the body, but at this stage the animals invariably perished, and Dr. Farre had no opportunity of witnessing their further metamorphosis.*\nReproduction by ova. \u2014 In the genus Pedicel-lina Van Beneden discovered in most of the individuals he examined, situated immediately above the stomach, some rounded opaque corpuscles of a lactescent appearance {fig. 65, k), which seem to be attached to that viscus ; this he considers to be the ovary, containing ova in various stages of development. In the same situation he perceived an organ that he\n* Phil. Trans. 1837, p. 410.\nFig. 65.\nPedicellina Belgica.\nA. Section. B. A group of individuals in various states. The letters refer to each of the polypes, a, mouth ; b, oesophagus ; c, stomach; d, pylorus; e, intestine; f anus; g, tentacular sheath; h, tentacles; i, oral disc ; k, ovum in the ovary; l, parietes of the polypary; m, stalk; n, superior, and o, inferior, enlargement ; p, muscles of the stalk; q, intermuscular cellules? 1. An adult individual retracted into its cell, showing the muscular fasciculi ; r, sphincter ; s, retractor ; t,\noblique ; u, v, animalcules accidentally attached to the stalk ; 2, 3, 4, polypes in the act of expanding ; 5, 6, 7, young individuals ; 8, buds in diff\u00e9rent stages of development ; a, 8, very rudimentary ; b, 8, showing the cellule ; c, 8, d, 8, a little more advanced ; e, 8, the embryo visible ; 9, the connecting stalk; 10, an enlargement giving rise to several buds; 11, tentacle magnified ; 12, a little group of the natural size. (After Van Beneden.')","page":59},{"file":"p0060.txt","language":"en","ocr_en":"POPLITEAL REGION.\n60\nlooks upon as being the testis, his opinion being founded on the fact that when a mature specimen of the animal is placed between two plates of glass, and gently compressed so as to rupture its parietes and cause the escape of the viscera, spermatozoa are discoverable in the one and ova in the other. The spermatozoa exhibit considerable vivacity in their movements, have a disc-like body and a caudal filament, and are proportionately of large size ; around them may be seen multitudes of free cellules without caudal appendages, which are apparently young spermatozoa.\nIn some individuals the spermatozoa are so numerous that the intestinal canal appears completely enveloped by them, and the whole peri-intestinal cavity seems alive with their movements.\nIn the mature ovary ova are discoverable in different degrees of development, in each of which the vesicles of Wagner and of Purkinje are, according to Professor Van Beneden, distinctly visible. In those ova which approach their complete maturity an external vitelline membrane, or chorion, and a vitellus are perceptible, but the two vesicles above mentioned have disappeared.\nWhen arrived at the proper term the ova break from their envelope, or ovisac, and fall into the general cavity of the body, where they move freely about surrounded on all sides by spermatozoa. At length the eggs accumulate in the interior of the body, near the base of the tentacula, and their escape,as witnessed by Van Beneden in Laguncula repens, is at length accomplished in the following manner. An egg presents itself at an orifice, situated in the vicinity of the anus, through which its external membrane partially protrudes, constituting a sort of hernia {fig. 61,p). The vitellus gradually flows from the still enclosed portion of the egg into that which is external, and when the vitellus has thus entirely passed out, the egg is found separated from the parent animal and falls into the surrounding water. These eggs are entirely destitute of external cilia, and are carried off by any casual current to attach themselves where chance may bring them ; they are also remarkable for the irregularity of their shape, some being completely angular, their form seeming to depend upon the pressure they have been subjected to in the interior of their parent.\nDevelopment by ova. \u2014 In Pedicellina Professor Van Beneden has witnessed the escape of upwards of twenty eggs from a single individual. They are of a pyriform figure, and enclosed in a pellucid membrane, by the intervention of which they adhere together (fig. 66. 1), so that in the interior of the body of the parent Bryozoon they have a racemose appearance, and when extended spontaneously they are generally united together in pairs. Between the vitellus and the envelope of the e\u00b0g there is always a small quantity of a transparent whitish fluid, which doubtless represents the albumen, while the pellucid external membrane itself is the chorion.\nThe vitellus breaks up intd granules, at first of large size, and afterwards by sub-\ndivision of smaller and smaller dimensions, giving a tuberculated appearance like that of a raspberry to the mass. This division seems to be accomplished exactly as in the ova of the higher animals, the yolk first separating into two (fig. 66. 3), then into four (fig. 66. 2), after which its breaking up proceeds rapidly (fig. 65. 4).\nFig. 66.\nA series \\illustrating the development hy ova of Pedicellina. (After Van Beneden.')\nThe embryo enclosed within the egg soon assumes a rounded form and speedily appears divided by two indentations near its middle (fig. 66. 5), by which it is separated into an anterior and a posterior moiety, and vibratile cilia become apparent upon the anterior extremity.\nThat portion where the cilia have become apparent insensibly enlarges and assumes the shape of a funnel (fig. 66. 6), while the long cilia by which it is fringed begin to keep the particles suspended in the water around them in rapid motion. The margins of the funnel gradually extend themselves (fig. 66. 7), the body exhibits frequent contractions, and at the end of about two hours little tubercles become apparent upon its anterior extremity, which subsequently become developed into the tentacula. Professor Van Beneden thinks that the original cilia disappear when the tentacula have become developed and furnished with their proper vibratile apparatus. The formation of the tentacula at once indicates which are the two extremities of the body and the point by which the embryo will subsequently attach itself.\nThe embryo when mature is quite at liberty and strikingly resembles some forms of Infusoria, but after a little while a pedicle is formed, whereby it proceeds to fix itself to some foreign body, and thus permanently assume the aspect of its race (fig. 66. 8). The pedicle seems to be formed by a cell developed below the stomach, which grows directly outwards, and thus completes the organisation of the young Bryozoon.\n( T. Rymer Jones.)\nPOPLITEAL REGION, and POPLITEAL ARTERY. \u2014 The term Popliteal Region is applied to that portion of the","page":60},{"file":"p0061.txt","language":"en","ocr_en":"POPLITEAL REGION.\t61\nlower 1 extremity which occupies the bend of the knee, and includes also the posterior surface of the thigh, as high as the junction of its middle and lower thirds, and the back part of the upper fourth of the leg : \u2014 by its muscular boundaries this region is distinctly defined, and is of a diamond shape, but it is by no means so accurately limited when examined with reference to its surface. The external form of the popliteal region differs materially in the flexed and extended position of the leg ; in the latter case, it has somewhat of an oval outline, the longest diameter, which is in the vertical direction, greatly exceeding the transverse : the greatest transverse breadth is at the bend of the knee-joint. The surface presents an elongated rounded projection, which is received above between two narrow ridges diverging from each other as they are traced downwards ; these latter are produced by the stretching of the skin over the tendons of the hamstring muscles, and are rendered still more distinct by a more or less deep groove, which separates them on either side from the general convexity of the region ; inferiorly, the convexity of the surface passes off insensibly to the calf of the leg : these characters are more marked in the strong and muscular. When the leg is bent upon the thigh, the roundness of the upper part of the region is lost, and gives place to more or less of a depression or pit between the still projecting ridges produced by the hamstring muscles ; this depression is popularly known as the hollow of the ham.\nThe popliteal region is scooped out into a deep, narrow, diamond-shaped cavity, to which in the following description the term \u201c popliteal space\u201d will be applied; it is situated between the diverging hamstring muscles and the converging heads of the gastrocnemius, and is broader above the knee-joint than below ; it is filled up by a considerable quantity of fat with areolar tissue, and traversed by the popliteal vessels and nerves ; the semi-tendinosus and semimembranosus muscles on the inner side, and the biceps flexor cruris on the outer, bound this space laterally and above ; the two heads of the gastrocnemius with the plantaris muscle form its lateral boundaries below ; anteriorly it is bounded by the posterior surface of the femur, the knee-joint or rather its posterior ligament, and the popliteus muscle, and is closed in posteriorly or superficially by a strong fascia and the skin : it may be as well to mention, that in dissecting the popliteal space we are looking at it from behind, so that the term superficial relates to its posterior aspect. Before describing the contents of the space, it will be necessary to consider more at length the structures which constitute its boundaries.\nThe skin and subcutaneous areolar tissue present no very remarkable features for examination ; the former is marked at the bend of the joint by a few transverse furrows, which are obliterated when the leg is fully extended ; it is smooth and adherent to the subjacent tissue. This latter differs in no respect from\nthe same structure elsewhere; it contains a variable amount of fat, and is traversed above by a few filaments from the posterior cutaneous nerve of the thigh, and below, though not invariably, by the posterior saphena vein. This superficial vessel begins, by small branches, at the outer side of the foot, passes behind the outer malleolus, and crosses obliquely to the middle line of the leg, then ascends vertically upon the aponeurosis, which it frequently perforates before reaching the popliteal region, passes into the space between the heads of the gastrocnemius to terminate in the popliteal vein ; it occasionally sends upwards a branch upon the fascia lata, which, winding round the inner side of the thigh, joins the saphena major vein. The commu-nicans tibialis nerve courses with this vein, which it closely accompanies at the lower part of the leg, but is separated from it in the popliteal region by being buried between the heads of the gastrocnemius. The posterior saphena vein is liable to become varicose, but less frequently so than the saphena major : this circumstance is of course readily accounted for by the difference of length and size between the two.\nThe fascia lata, descending from the posterior surface of the thigh, forms the strong aponeurosis which closes in the popliteal space behind ; stretched across this region, it is connected on either side with the condyles of the femur and the tendons of the extensor muscles of the leg, and continued around the joint ; it is especially fixed to the outer lip of the linea aspera by a septal process of the fascia lata which dips between the vastus ex-ternus and biceps muscles, and on the inner side receives fibres from the tendons of the muscles which pass behind the inner condyle ; it approximates the lateral boundaries of the space, gives to it a greater depth, and protects the vessels and nerves by bearing off from them any undue pressure. By its unyielding and dense structure, aneurismal or other swellings are delayed in their approach to the surface, and for the same reason abscesses are prone to burrow and require an early and free opening. This aponeurosis presents numerous transverse fibres, is perforated sometimes by the saphena minor vein, and is adherent by fibrous slips with the subcutaneous areolar tissue ; it is continuous below with the aponeurosis of the leg.'\nThe muscles forming the boundaries of the popliteal space will be considered only so far as they relate to it ; their more detailed description will be found in the articles Muscles of the Leg and Thigh. The semitendinosus muscle, after separating from the biceps, terminates in along, slender tendon, which descends inwards, lying upon the surface of the semimembranosus ; then crosses the inner head of the gastrocnemius, and placed between it and the tendon of the semimembranosus, winds round the inner condyle to pass to its insertion. The semimembranosus in descending at first crosses obliquely the popliteal artery, continues membranous and fleshy to the condyle of the","page":61},{"file":"p0062.txt","language":"en","ocr_en":"62\tPOPLITEAL REGION AND ARTERY.\nfemur, and is of sufficient breadth, at this its lower part, to extend beyond either side of the tendon of the former muscle, thus contracting the lateral dimensions of the bottom of this space by encroaching within it. The long head of the biceps, leaving the former muscles, descends obliquely to cross the outer origin of the gastrocnemius by its strong tendon, which is subsequently implanted into the head of the fibula ; it receives, as it descends, the thick fleshy mass of its shorter portion, which assists the semimembranosus in narrowing the bottom of the popliteal space, shutting it in also externally and above, by its attachment to the linea aspera as low as the outer condyle. The superior angle of this space is formed at the point of divergence of these hamstring muscles, and the lateral angles are occasioned by their crossing the heads of the gastrocnemius ; this latter muscle is attached to either condyle of the femur by its two heads, the internal being the longer and larger ; they converge to unite in the median line a little below the knee-joint : these origins have each a bursa interposed between them and the condyle ; the little fleshy belly of the plantaris muscle accompanies the outer head and lies beneath it ; by their union the inferior angle of the popliteal region is produced. At the bottom of the space we meet with, first, the posterior, flat, triangular surface of the femur, and, secondly, the back part of the knee-joint strengthened by its posterior ligament (the ligament of Winslow). This structure is derived from the tendon of the semimembranosus ; it insinuates itself beneath the inner head of the gastrocnemius, and, forming a flat and dense tendinous aponeurosis,extends across the back of the joint to the external condyle, adheringto the synovial membrane : there are several small openings in it, produced by a separation of its fibres, for the passage of vessels to the interior of the articulation :\u2014lastly, the popliteus muscle, which is flat, triangular, and situate behind and below the joint, begins, by a round tendon, from the outer condyle and spreads out by muscular fibres upon the posterior surface of the tibia to be inserted into its oblique ridge.\nOn removing the fascia, two large nerves are seen to traverse the popliteal space, and are indifferently called the internal popliteal or tibial, and the external popliteal or peroneal nerves ; they are the terminal branches of the sciatic, which nerve generally bifurcates at the upper angle of this region : the point of division, however, is very variable, sometimes occurring even within the cavity of the pelvis, in which case, as the two nerves emerge, they are usually separated by a slip of the pyriformis muscle ; commonly a very trifling dissection will affect their separation some distance up the thigh. The internal popliteal or tibial nerve is the larger of the two, and appears to be the continuation of the sciatic ; it takes a nearly perpendicular course through the popliteal space in the middle line, and will be found at first to lie almost immediately beneath the fascia, a small quantity of fat intervening ; it dips more deeply into the space as it descends, passes between the heads\nof the gastrocnemius and over the popliteus muscle, and, insinuating itself beneath the tendinous arch of the soleus, courses down the back of the leg under the name of posterior tibial. Owing to the oblique direction which the popliteal artery follows, this nerve alters its relation to it at different parts of its course ; until they reach the bend of the knee, the nerve is a little distance to the outer side of the artery, but superficial or posterior, and separated from it by a thick layer of adipose tissue : at the joint, the nerve is still posterior to,but in closer relation with it, and subsequently upon the popliteus muscle crosses the artery to gain its inner side. About the centre of the popliteal space, the tibial nerve sends off a small branch called the communicans tibialis, which descends superficially between the heads of the gastrocnemius,and is afterwards concealed in agroove formed lay their union ; it perforates, at a variable point, the aponeurosis of the leg, and, descending towards the outer malleolus, is joined a little above it by the communicans peronei, a branch of the peroneal nerve ; thus reinforced, it is increased in size, and, accompanied by the posterior saphena vein, winds behind the outer ankle to be continued along the outer side of the foot. To return to the internal popliteal nerve, which sends off, while crossing the back of the joint, four or five other branches for distribution to the gastrocnemii and plantaris muscles, and also furnishes some articular twigs ; these are all accompanied by corresponding branches of the popliteal artery, and from their situation are liable to be compressed by an aneurismal tumour. The external popliteal or peroneal nerve descends along the inner side of the biceps muscle, by which it is guided to the head of the fibula, and winds round the neck of that bone beneath the peroneus longus muscle to divide into its terminal branches ; in the ham it gives off the small branch called the communicans peronei. This will be seen to descend over the outer head of the gastrocnemius muscle and beneath the fascia, and, piercing the aponeurosis of the leg at a very variable distance above the outer angle, joins the communicans tibialis ; it presents frequent varieties both with regard to its size and the point of junction with the last-named nerve : occasionally the union occurs in the popliteal space. To reach the popliteal vessels, a quantity of fat which fills up this space must be dissected out : it is very abundant, and surrounds and supports the popliteal artery.\nThe Popliteal Artery is simply a continuation of the femoral, and is so named immediately after the latter vessel has passed through the elliptical aperture of the adductor muscles ; this opening is bounded above by the united tendons of the adductor longus and adductor magnus muscles ; inferiorly, by the union of the vastus internus tendon with that from the adductor magnus which descends to the inner condyle ; externally, by the tendon of the vastus internus, and internally, by that of the adductor magnus. Passing through this tendinous aperture, the artery is at first situated on the inner side of the femur at the junction of its middle","page":62},{"file":"p0063.txt","language":"en","ocr_en":"POPLITEAL ARTERY.\nand inferior thirds, and descends obliquely outwards and from before, backwards through the popliteal space, to the lower border of the popliteus muscle, where it terminates, after having gradually diminished somewhat in size, by dividing into the anterior and posterior tibial arteries. When viewed with regard to the vertical axis of the popliteal region, the artery certainly takes an oblique course outwards ; but in reference to the mesial and perpendicular line of the body, this obliquity is more apparent than real, and depends upon the direction inwards which the shaft of the thigh bone follows ; and this appears evident by the artery passing vertically and midway between the condyles of the femur. Its course from before backwards is very decided until it has attained the superior border of the popliteus muscle; but as the lower portion of the popliteus is on a plane a little anterior to the upper, and as the artery is applied upon its posterior surface the course will be changed for a direction forwards, so that the artery describes a slight curve, convex backwards, and the concavity corresponding with the back of the knee-joint. When the leg is flexed upon the thigh, the popliteal artery follows the bend of the articulation, and is curved forwards without lateral tortuosity, the curve agreeing with the angle of flexion ; this alternate straightening and bending of the artery during the movements of the leg has been assigned as a reason for its being so frequently the seat of aneurism ; on the other hand, it has been stated that forced extension of the leg, carried even to rupture of the ligaments of the joint, may be made without injury to the artery. The popliteal artery is closely related to its accompanying vein ; as they are entering the space, the vein lies to the outer side of the artery, and superficial or posterior to it, and changes its relation near the joint only to become still more directly posterior : they are enveloped in a common sheath, which is continued from the femoral region (see Femoral Artery), and by which they are intimately connected with each other. The artery is at first deeply seated in the popliteal region, and guided into it by the inferior boundary of the elliptical tendinous opening; it then descends obliquely upon the flat triangular surface of the femur to the knee-joint, resting in its course upon a cushion of fat which is interposed between it and the bone, and thicker below than above, so as to well support the artery as it inclines backwards from the femur to reach the posterior aspect of the joint. For some distance from its commencement it is concealed beneath the semimembranosus muscle, the thick fleshy belly of which obliquely crosses it behind ; emerging from under cover of this muscle, the artery continues its course to the condyles of the femur, between the biceps on the outer side, and semimembranosus and semitendinosus on the inner ; a considerable quantity of fat separates it from, posteriorly, the aponeurotic fascia, closing in the space behind, and from the skin. As the internal popliteal or tibial\n63\nnerve descends vertically in the axis of this region, it must necessarily lie to the outer side of the artery in this part of its course ; and as the nerve is found almost immediately beneath the fascia, it is therefore superficial or posterior to the artery, from which it is separated by more or less fat. While thus buried in fat, three or four lymphatic glands are closely related to the artery, often indeed surrounding it, one to either side, another superficial, and a fourth occasionally found between it and the femur. Should any of these glands become enlarged, the impulse such swelling would receive from the artery might lead to its being mistaken for aneurism. We next find the popliteal artery crossing the bend of the knee-joint, and resting upon its posterior ligament ; it descends between the condyles of the femur and the two heads of the gastrocnemius to the upper border of the popliteus muscle: the little fleshy belly of the plantaris is also related to its outer side. In this stage the accompanying vein is more directly behind it, and the tibial nerve, coming into closer relation with the artery, from which it is separated by the vein, is also posterior or superficial to it, with a tendency to cross to its inner side. At this part of its course the nerve usually sends off, first, the communicans tibialis, and then its branches to the heads of the gastrocnemius, so that the relation which the nerve and its branches have to the artery at this point will readily account for the pain or numbness generally attendant on aneurismal tumours in this region ; so, also, for cedematous swelling of the leg under the samer circumstances, we have only to refer to the relative anatomy of the vein and artery for its explanation ; posteriorly, the artery is separated from the fascia and integument by more or less fat, and is still a considerable distance from the surface ; for the tendons of the hamstring muscles, and the condyles of the femur with the heads of the gastrocnemius, so bear off from the artery the skin and fascia as to leave it in a deep and narrow hole, resting upon the posterior ligament of the joint, and concealed behind by, first, the vein, and then the tibial nerve. Of course any operation upon the artery while thus situated would be impracticable. Lastly, the artery gains the posterior surface of the popliteus muscle, upon which it descends to terminate by dividing into the anterior and posterior tibial vessels ; this division occurs at the lower border of the muscle, and opposite the interval between the tibia and fibula. The artery is deeply concealed between the heads of the gastrocnemius as they approach each other to unite; the tibial nerve crosses to gain its inner side, and the vein, which often receives the tibio-peroneal vein while upon the popliteus, is still posterior to the artery.\nVarieties.\u2014The popliteal artery very seldom exhibits any deviation from its usual arrangement ; occasionally, its point of division occurs higher in the popliteal space. Professor Harrison mentions to have seen the artery divide between the condyles of the femur. Instances","page":63},{"file":"p0064.txt","language":"en","ocr_en":"PORIFERA.\n64\nhave been recorded of a high division of the femoral artery (see Femoral Artery), and where two popliteal arteries existed ; but the artery generally appears particularly free from any variety.\nBranches of the popliteal artery.\u2014These are very numerous, and of considerable importance in maintaining a collateral circulation when the femoral artery has been obliterated by operation or disease ; they are not always constant, either in number or size. The popliteal artery first sends some irregular branches to the hamstring muscles, the rami musculares superiores ; then five articular arteries, two of which usually arise a little above the joint, and are called external and internal superior articular, and two below, the external and internal inferior articular ; thelastis an azygos branch. After giving off these articular arteries, the popliteal sends several large branches to the gastrocnemii muscles, the rami musculares inferiores.\nThe superior muscular branches are two or three in number, which are distributed on either side to the hamstring muscles and anastomose with the perforating arteries of the profunda. The superior external articular artery is of some size, and arises from the outer side of the popliteal at a variable distance above the outer condyle of the femur; it descends to wind round the bone under the biceps muscle, which latter it supplies and divides into superficial and deep branches ; the former are distributed to the vastus externus muscle, and, by passing through its substance, terminate on the patella ; the latter supply the synovial lining of the articulation, and the lower extremity of the femur itself. These branches anastomose with those of the inferior external articular artery, and with the long branches of the external circumflex from the\u00b0profunda, which descend in the substance of the vastus externus towards the knee.\nThe superior internal articular artery arises from the inner side of the popliteal above the inner condyle, and also winds round the femur, passing beneath the tendon of the adductor magnus muscle; like the external articular, it divides into superficial and deep branches, the former penetrating the vastus internus to ramify on the patella, and anastomoses with the external articular and the anastomotica magna from the femoral; the deeper branch is distributed to the synovial capsule and femur.\nThe azygos branch is derived from the anterior aspect of the popliteal while it is in relation with the posterior ligament of the joint ; it divides into branches which pass through the ligament, and supply the synovial membrane and crucial ligaments of the joint. The inferior external articular is given off from the outer side of the popliteal a little below the articulation, and winds round the outer surface of the external semilunar cartilage, passing beneath the plantaris and outer head of the gastrocnemius muscles ; it then courses forward above the head of the fibuia, and beneath the external lateral ligament to divide into branches, which anastomose with the anterior tibial recurrent and the other articular arteries. The inferior internal articular artery is generally rather a\nlarge branch, and descends to the internal lateral ligament, beneath which it passes to gain the front of the tibia; it divides into numerous branches which are distributed to the structures about the inner side of the joint, and which anastomose also with the other articular branches.\nThese articular branches of the popliteal are seen, when well injected, to form a beautiful network of vessels around the knee-joint; by anastomosing with the external circumflex and perforating branches of the profunda, with the anastomica of the femoral and the recurrent tibial artery, and also with each other, a very sufficient collateral circulation is usually maintained in cases where the femoral artery has been obliterated.*\nThe inferior muscular branches are derived from the popliteal artery while passing between the heads of the gastrocnemius ; they are four or five in number, and often of considerable size; accompanied by branches from the tibial nerve, they descend in the substance of the gastrocnemii muscles, and maybe traced sometimes to the tendo Achillis ; generally, a small branch from one of them descends with the communicans tibialis nerve. These vessels are sufficiently large as occasionally to require a ligature after amputation of the leg.\nThe course of the popliteal vein has been already noticed in connection with the artery; it is remarkable for the thickness of its fibrous coat, and is formed by the junction of the anterior tibial veins with a trunk called the tibio-peroneal : this latter vessel is produced by the confluence of the posterior tibial and peroneal veins. The popliteal vein receives the veins which accompany the branches of the popliteal artery, and also, about the centre of this region, the vena saphena minor.\nOperative relations of the popliteal artery.\u2014 Operations upon the artery in this region are now never undertaken, unless, perhaps, in cases of injury with an external wound, the size and direction of which will vary the surgical treatment to be adopted ; a ligature may be passed round the artery in the upper part of its course as it emerges from beneath the semimembranosus muscle, the outer edge of which will act as a guide to the first incision. After dividing the fascia, the finger, sunk into the space and carried upwards upon the outer surface of the semi-membranosus, will reach the artery ; the vein lies behind it, and a little to the outer side, and will therefore be reached first ; the needle must be insinuated between the artery and vein, and carried round the former from without inwards. This operation is mentioned merely as being practicable ; in the rest of its course the relations of the artery are such as to prohibit any surgical operation upon it.\n( William Trew.)\nPORIFERA (iropos (p\u00e9pco, canal-bearing). A word applied by Professor Grant to designate\n* I have witnessed one instance where mortification of the leg ensued after the application of a ligature to the femoral artery for the cure of popliteal aneurism; amputation was performed above the knee.","page":64},{"file":"p0065.txt","language":"en","ocr_en":"PORIFERA.\na remarkable class of organized beings, dubiously admissible into the animal series, usually known by the name of Sponges, which are met with in great abundance in the seas of most climates, either growing in isolated masses from the rocks or spreading out so as to encrust the surfaces of submarine bodies with a kind of living carpet, the texture of which varies in accordance with the nature of the sponge. By recent naturalists, the term Amorphozoa (ap.6p(pos, shapeless; |<\u00a3ov, animal) has been considered a preferable designation, and accordingly these names will be applied indiscriminately throughout the present article.\nAccording to the most recent authors, the members of the class before us may be generally described as follows : \u2014 \u201c Organized bodies growing in a variety of forms, permanently rooted, unmoving and unirritable, fleshy, fibro-reticular or irregularly cellular, elastic and bibulous, composed of a fibro-corneous axis or skeleton, often interwoven with siliceous or calcareous spicula, and containing an organic gelatine in the interstices and interior canals ; reproduction by gelatinous granules generated in the interior, but in no special organ. All are aquatic, and, with a few exceptions, marine.\u201d *\nThe families composing the class thus characterised are distinguished by the nature of the skeleton or solid framework upon which their shape depends, in accordance with which Blainville has arranged them as follows : \u2014\nAlcyoncellum. \u2014 Body fixed, soft, sub-gelatinous, solidified by tricuspid spicula, phytoid ; branches not numerous, cylindrical, fistular, terminated by a rounded orifice, with thick walls composed of regular granules ; polygonal, alveoliform, pierced with a pore externally and internally.\nSpongia. \u2014 Body soft, very elastic, multiform ; more or less irregular, very porous, traversed by tortuous canals, which are numerous, opening externally by distinct oscula, and formed by a kind of subcorneous substance which anastomoses in every direction ; entirely without spicula.\nCalcispongia.\u2014Body notvery soft,formed in irregular masses, porous, traversed by irregular canals, which open externally by oscula, and composed of a subcartilaginous substance, supported by calcareous spicula that are, for the most part, stelliform.\nHalispongia\tsilex). \u2014 Body more\nor less rigid or friable, in an irregular mass, porous, traversed by tortuous canals terminating by oscula scattered over the whole surface, and composed of a subcartilaginous substance supported by simple spicula, which are silicious.\nSpongilla. \u2014 Body an irregular mass, more or less rigid and friable, pierced with pores, but without true oscules, composed of a fibrocartilaginous substance, which is in small\n* History of British Sponges and Lithophytes, by Geofge Johnston, M. D., Edinburgh, 1842.\nVOL. IV.\n65\nquantity compared with the great number of simple silicious spicula which solidify it.\nGeodia. \u2014 A fleshy body, tuberiform, irregular, hollow internally, and formed externally by a sort of crust or envelope pierced with a great number of pores, and containing a group of oscules or larger pores placed in a little subcircular space.\nSiphonia. \u2014 Body polymorphous, free or fixed, composed of dense fibres, forming two sorts of canals, some larger and longitudinal, opening by oscula at the bottom as well as on the summit, the others transverse and anastomosing, radiating towards the periphery, and provided with a terminal depression, more or less considerable, in which the oscules are collected in a radiated manner.\nScvphia. \u2014 Body cylindrical, simple or branched, terminated by a large rounded os-cule, and entirely composed of reticulated tissue.\nEudea. \u2014 Body filiform, attenuated sub-pedunculate at one extremity, large, round, and pierced with a great oscule at the other, with pores scarcely visible in irregular lacunae ; whole surface reticulated.\nHallirrhoa. \u2014 Body turbinated; almost regular, with the circumference circular or lobed, covered with cellules or pores, which are indistinct externally, with a large oscule in the centre of its enlarged part.\nTethium. \u2014 Body subglobular, irregular, tuberiform, sarcoid but firm, suberous, resisting, supported by and mixed up with an immense quantity of aciculi, which are simple,\nFig. 67.\na, Tethea Cranium of the natural size ; h, section of the same. (After Johnston.)\nF","page":65},{"file":"p0066.txt","language":"en","ocr_en":"66\nPORIFERA.\nfasciculate, and diverging from the centre to the circumference.\nSkeleton. \u2014 The framework, or fibrous portion, from the arrangement of which the sponge derives its form is composed, as we may gather from the preceding table, of various materials differently disposed in different species, and it is upon the modifications in\nFig, 68.\nA minute portion of the surface of Teihea Cranium magnified; spicula projecting beyond the surface. (After Johnston.')\nthe nature and arrangement of the solid portions that the general characters of the mass depend. In the true sponges (Spongia), so remarkable for their elasticity and softness, and for their capability of absorbing fluids, properties which render them valuable for many important uses ; the whole substance is composed of horny subcylindrical fibres, which ramify and interlace in every possible direction, anastomosing with each other so as to form innumerable continuous cells and intricate canals, the walls of which, in the recent sponge, are crusted over with the gelatinous\nFig. 69.\nSingle interspace or open cell, and surrounding finer mesh-work of the skeleton of Euplectella Aspergillum. (After Owen.)\nliving cortex. The horny threads composing this inextricable labyrinth are of unequal thickness, and by some writers have been erroneously described as being throughout tubular ; but this latter is a mistaken view of their structure, dependent upon optical appearances, as has been proved by Mr. Bower-bank * and others, the horny fibres being, in fact, solid and imperforate.\nIn a second group of Sponges, called Halichondria (yaXiS, silex ; xov^Post cartilage), the solid framework of the body is principally made up of silicious spicula, imbedded in the fibre or parenchyma of the\n* Microscopic Journal, vol. i. p. 10.\nsponge. These spicula, which are composed of pure silex, are generally united into fasciculi by an enveloping glutinous or condensed cellular substance, and by the junction of these fasciculi in various modes fibres are formed, which traverse every part of the body, forming the boundaries of canals and orifices, and giving form and support to the whole of the gelatinous or soft cellular substance of the animal.* The spicula, so far as the British species are concerned, Dr. Johnston observes, seem to be always in the shape of simple needle-like crystals (fig. 70) ; nor does any\nFig. 70.\nA minute film of the rind of Tethea Lyncurium compressed between plates of glass, and highly magnified to show the needle-like and starred spicula. (After Johnston.)\nspecies present us with spicula of two different forms, though they sometimes vary much in length and gracility ; but he cannot assent to the opinion of Dr. Grant that the form is different in every distinct species, otherwise the task of distinguishing them would be comparatively easy.f\nA third group of Sponges, designated by Blainville, Calcespongia, has the framework which gives them form solidified by the presence of spicula, which are entirely composed of carbonate of lime : in sponges belonging to this group there is, according to Dr. Johnston, no net-work, their basis being a porous membrane, rendered compact by the profusion of spicula imbedded in it. The siliceous spicula belonging to the preceding group form mostly needle-like spines ; but there are found along with them, in the genus Tethea, some that might have been the model from which mythological painters might have drawn the trident they have placed in the hands of Neptune. (fig. 71, d). The calcareous spicula are more variously shaped \u2014 either simple and acicular or clavate, or formed with three, or even sometimes with four prongs. The two kinds, viz. the calcareous and siliceous, have not hitherto been detected co-existent in any British sponge ; but the spicula of every species are very constant to the same figure, although in point of size they vary exceedingly. J \u201c When these spicula are examined through the microscope after exposure to a red heat, we distinctly perceive,\u201d says Dr. Grant \u00a7, \u201c a shut\n* Grant, Comp. Anat. p. 5. f British Sponges, p. 89.\nJohnston, loc. cit.\nEdin. Phil. Journ., xiv. p. 184.","page":66},{"file":"p0067.txt","language":"en","ocr_en":"PORIFERA.\n67\nFig. 71.\na, c, d, Spicula of Tethea Cranium; d, three forked spicula; c, fusiform spicula; a, cuticular spicula; b, spicula of Tethea Lyncurium. (After Johnston.y\ncavity within them, extending from the one point to the other ; and on the inflated part of each spiculum we observe a ragged opening, as if a portion had been driven out by the expansion of some contained fluid. In those spicula which had suffered little change of form by their incandescence, I have never failed to observe the same cavity within extending from one end to the other, and a distinct open rent on their side by which the contained matter has escaped.\u201d The existence of this central cavity has likewise been recognised by Mr. Bowerbank, who, moreover, observes, that it is \u201c lined with an animal membrane, which becomes converted into a thin film of carbon when the spicula are exposed to the action of the blow-pipe.\u201d\nGelatinous cortex.\u2014\u201c In the recent and living sponge, all its canals and pores are filled with a glairy colourless fluid like the white of an egg, which flows freely out on the removal of the sponge from the water. The quantity of this fluid varies according to the species. In some, it is copious even to nauseousness, but in the compact Halichondri\u00e6, there is little of it, and in the Granti\u00e6 it appears to be entirely wanting.\u201d * It \u201c has an unctuous feel, emits a fishy odour when burnt, leaves a thin film of membrane when evaporated, and appears to the naked eye, transparent, colourless, and homogeneous, like the white of an egg : but when a drop of it is examined on a plate of glass under the microscope, it appears entirely composed of very minute,transparent, spherical or ovate granules like monads with some moisture. These monad-like bodies, nearly all of the same size and form, resemble the pellucid granules or vesicles which Trem-bley has represented as composing the whole texture of the Hydra, or the soft granular matter we observe in the stems of living Ser-\ntulari\u00e6 ; and indeed most of the fleshy parts of organized bodies appear to be composed of similar pellucid granular or monad-like bodies in different states of aggregation.\u201d* The sensible qualities of this glairy material vary in different species of sponge,\u201cthe odour of some being decidedly animal, while others belong to common and well-known vegetables. The Spongia coalita, when newly taken out of the water, smells very strongly of the common mussel, and when burnt it still resembles the same bivalve burnt ; the Spongia compressa, on the other hand, smells strongly of the common mushroom ; some, as the Spongia oculata, have scarcely a perceptible odour.\u201d\nIrritability. \u2014 According to Audouin | and Milne Edwards, when a living Tethea is allowed to remain for some time perfectly undisturbed in a vessel of sea-water, its oscula may be observed widely expanded, and the currents, hereafter spoken of, passing through them may be readily observed. But if, in this condition, the animal is disturbed or removed for an instant from the water, the currents grow much feebler, or cease altogether, and the oscula, contracting slowly and insensibly, become at last almost obliterated. In other genera of sponges, however, this contraction has been looked for in vain ; and although the openings of the oscula have been watched with the utmost attention, and measured at intervals with miscroscopic accuracy, not the slightest movement has been perceptible.\nCirculation of Water.\u2014 In the living sponge, as was first remarked by Professor Thomas Bell, and subsequently by other observers, a constant circulation of the surrounding element, is, by some mysterious agency, kept up throughout its substance, the water being perpetually sucked in, as it were, through all the minute pores, upon the periphery of the mass, and again emitted in continuous streams through the larger orifices (oscula) of the sponge.\nFig. 72.\nLiving Papillaris, showing the jets of water emitted from the oscula. (After Blainville.)\nDr. Grant put a small branch of Spongia coalita with some sea water into a watch-glass, in order to examine it with the microscope, and thus describes the phenomena it pre-\n* Grant, loc. cit.\nf Hist. Nat. du Litt, de la France, vol. i. p. 78.\nF 2\nJohnston, loc. cit.","page":67},{"file":"p0068.txt","language":"en","ocr_en":"PORIFERA.\n68\nsented:\u2014\u201c On moving the watch-glass, so as to bring one of the apertures on the side of the sponge fully into view, I beheld, for the first time, the splendid spectacle of this living fountain, vomiting forth from a circular cavity an impetuous torrent of liquid matter, and hurling along in rapid succession, opaque masses, which it strewed every where around. The beauty and novelty of such a scene in the animal kingdom, long arrested my attention ; but after twenty-five minutes of constant observation I was obliged to withdraw my eye, from fat'gue, without having seen the torrent, for one instant, change its direction, or diminish, in the slightest degree, the rapidity of its course; I continued to watch the same orifice, at short intervals, for five hours, sometimes observing it for a quarter of an hour at a time, but still the stream rolled on with a constant and equal velocity. About the end of this time, however, I observed the current become perceptibly languid ; the opaque floc-culi of feculent matter, which were thrown out with so much impetuosity at the beginning, were now propelled to a shorter distance from the orifice, and fell to the bottom of the fluid within the sphere of vision, and, in one hour more, the current had entirely ceased.\u201d\nSubsequently, two round portions of the Spongia panicea were placed together in a vessel of sea-water, with their orifices opposite to each other, at the distance of two inches ; they appeared to the naked eye like two living batteries, and soon covered each other with feculent matter. Dr. Grant then placed one of them in a shallow vessel, and just covered its surface and highest orifice with water. On strewing some powdered chalk on the surface of the water, the currents were visible at a great distance, and on placing some small pieces of cork or of dry paper over the apertures, he could perceive them moving by the force of the currents at the distance of ten feet from the table on which the specimen rested. A portion of soft bread pressed between the fingers into a globular form was not moved away in a mass by the stream, but was gradually worn down by the current beating on its sides, and thus propelled to a distance in small flakes. A globule of mercury of equal diameter with the orifice, let fall upon it from a glass tube, was not removed or shaken, and completely stopped the current. In this condition, on piercing the sponge with a needle, a new current was established through the artificial canal thus formed, which continued even after removing the obstruction from the original orifice.\nA globule of mercury of any smallness placed over the orifice of a living sponge, is too heavy to be affected by the small column of water which impels against its smooth round surface, flowing at the rate with which it issues from that orifice, and is useful in enabling us to stop up the currents of certain orifices, in order to direct the stream with greater force through a particular aperture which we wish to examine through the mi-\ncroscope. By adopting this plan with some sponges, which have very few and large orifices on the surface, it is distinctly perceptible with the naked eye, that the current never enters by the same apertures through which it issues, and we might thus measure the whole strength of the forces employed to produce the currents in any particular specimen.*\nVarious hypotheses have been suggested to account for the production of these streams of water which constantly percolate the body of the sponge, but all of them have been rejected in turn as unsatisfactory. Ciliary movement might be supposed to be the cause of this phenomenon, were it not that no observer has been able to detect, even with the most powerful microscopes, the presence of cilia in the interior of the aquiferous canals. At certain seasons, indeed, when the ciliated reproductive gemmules described by Dr. Grant are abundantly disseminated through the living cortex of the sponge, it would seem possible that they might have some influence ; but as the currents appear to be equally strong at all periods, even when these gemmules are not developed, this supposition is untenable. Lastly, the laws of endesmosis have been appealed to as capable of explaining the phenomenon in question, yet even here there are difficulties not easily got rid of.\nIn speaking of this propulsion of the seawater through the Halichondria, in which genus it has been principally observed, the crustaceous species being best adapted for the study of its phenomena, Dr. Johnston remarks f, \u2018\u2018A single observation is sufficient to convince us that this circulation has nothing in common with that of higher animals, but it has some analogy surely with that imbibition and influx of water into the body of most radiated and molluscous animals which takes place through the skin and through certain canals, which Della Chiage has described and figured as their aquiferous system. The canals in both cases are not vascular tubes with membranous parietes, but rather furrows, excavated in the flesh or substance of the body, and leading into wider channels equally unlined. They have in common a direct communication with the circumfluent water, which alone ever flows in them, and the entrance of this water seems to be, in a great measure, or entirely, independent of the will of the animals ; but the polypes and mollusca only have the power of expelling it when they choose by the contraction and compression of the parts which the canals traverse. There is, however, a wider difference in the arrangement of the aqueducts, \u2014in the Radiata and Mollusca, the pattern is the same in every individual of each species, but in the Sponges it has no constancy, \u2014 so that in no two specimens of the same kind do we ever find the arrangement to be exactly alike.\nThis inconstancy seems to prove that the\n* Edin. Phil. Journal, vol. xiii. p. 104.\nf Hist, of British Sponges, p. 89.","page":68},{"file":"p0069.txt","language":"en","ocr_en":"PORIFERA.\ndirection of the aqueducts through the sponge, and the position of their orifices or oscula on the surface, is very much a matter of chance, and that their formation is the result of a mechanical cause liable to be diverted from its course by exterior circumstances. If we follow the growth of a sponge, we may feel still more confirmed in this view. The species begins as a spot-like crust of uniform texture, porous throughout, and nearly equally so. In this primitive, homologous condition, there is nevertheless a perfect circulation, \u2014 a current which seeks the interior, and another which flows from it, to mix with the circumfluent medium. As the sponge grows in extent and depth, the space for imbibition is enlarged, and the centrifugal water, in its efflux, flowing at first into one and then into more currents, these gradual^ make for themselves channels in the cellular texture, the fibres of which are pushed aside, and prevented, by the continuance of the stream, from again encroaching on its course. The channels increase in number with the continued increase of the sponge, and as it cannot but happen that they shall occasionally open into and cross each other, we have a wider canal formed by the additional flow of water into it. Such of these canals as reach the surface, soon effect for themselves an opening there ; for the current in it pushes against the superficial coat that opposes its efflux, and gradually thins and loosens its texture until this ultimately disappears leaving a fecal orifice or osculum. This is frequently a simple circular hole ; but often, on looking within the outer rim, we notice in the funnel from two to five lesser oscula united together, which are the openings of so many canals that have united there ; and sometimes we find spread within the osculum, or over its mouth, a net work of finer texture than the rest of the sponge, but otherwise of the same nature and composition.\u201d\n\u201c Such, we believe, to be the manner in which the canals and oscula are formed, and hence we cannot give our assent to the notion that the net-work spread over or within them is intended as a\u2018 wise provision \u2019* against the intrusion of noxious animals, or other foreign bodies within the sponge, which seems indeed to be sufficiently protected at these orifices by the efflux of the currents passing continually from them. Neither can it be supposed that the position and elevation of the oscula have\n* \u201c When -we cut a thin piece of the surface of \u00e0 living sponge, and look down through one of its pores with the reflecting microscope, we perceive, immediately beneath the projecting spicula which defend the pore, a very delicate network of gelatinous threads thrown over the entrance of the tube. This piece of structure is so fine as to be perfectly invisible to the naked eye ; it consists of five or six threads which pass in from the sides of the tube, to be connected with a central mesh ; so that there are five or six meshes thus formed ; and while this soft apparatus is beautifully defended by the protecting spicula of the pore, it serves still further to guard the interior of the animal from the smallest particles of sand or the minutest visible animalcules.\u201d\u2014 Grant, Edinb. Phil. Journ.\n69\nany foreseen relation with the situation of the sponge in the water. When, according to Dr. Grant, this production spreads level on a rock with an upright aspect, the oscula are raised into crater-like cones, to enable the sponge to clear itself of the excrementitiul matters carried out by the centrifugal streams ; but when it hangs pendent from the rock the oscula do not rise beyond the surface, because the necessity of ejecting excrementitial matters to a distance does not exist. This is to bestow a foresight and instinct on the sponge which even the followers of Lamarck would hesitate to give it, and which we may safely deny it to be possessed of. The form of the oscula depends entirely on the texture of the species, and on the force of the effluent currents. If the texture be loose and fibrous it yields easily, and the oscula are level, or nearly so : if more compact the skin is pushed beyond the surface into a papillary eminence ; and if too firm and dense to yield to the pressure behind, they fall into a level condition. They are also liable to be modified in some degree by external forces, for the littoral sponge, which, in a sheltered hollow, or fringed pool, will throw up craters and cones from its surface, may be only perforated with level oscula, when it is swept over, and rubbed down by the waves at every tide.\u201d\nReproduction.\u2014 The following are Professor Grant\u2019s recorded views upon this subject. \u201c Every part of the gelatinous matter (which invests the skeleton of the sponge) is covered with minute granular bodies, which are distinctly seen in every species of sponge by the weakest magnifier of the microscope. These granular bodies are represented in the plates of Donati of a spherical form, adhering to the quadriradial fibres of what he has named the Alcyoniuvi primum Dioseoridis. They are quite invisible to the naked eye ; they escape along with the gelatinous matter, and compose the greater part of it ; they are connected with each other by the gelatinous matter, and probably by the same medium, have some connection with the spicula, along which they are placed. No part in the organization of a sponge is more constant and obvious than these granular transparent bodies, lining the interior of every canal from the pores to the fecal orifices. Their form is not quite spherical, but somewhat lengthened and ovoidal, and they are always attached by one extremity to the gelatinous matter, while their opposite end is seen to project free into the cavity of the canals. Through the greatest magnifier of the microscope no difference can be detected in their forms in different species of sponge ; they all appear to be enlarged, and round at their free projecting extremity, and, when watched with attention, we distinctly see that they possess some power of spontaneous motion both when in connection with the sides of the canals and when lying isolated at the bottom of the water. The ova of the sponge are quite visible to the naked eye, and are seen disseminated through the whole texture of the sponge in the winter season. They are bodies of a\nF 3","page":69},{"file":"p0070.txt","language":"en","ocr_en":"70\nPORIFERA.\nyellow colour, somewhat translucent, pear-shaped, tapering more or less at their narrow end in different species ; their whole outer surface is covered with delicate projecting cilia, and when viewed through the microscope, in connection with the parent, we see that the rapid vibration of these cilia produces a distinct current in the water immediately around them, flowing always from their rounded free end towards their tapering fixed extremity, thus assisting the small granular bodies in producing the currents of the sponge during the period of their attachment to the body. They separate from the canals, and are propelled through the fecal orifices early in spring. None of these ova are seen in the sponge in summer, though we can detect no difference in the velocity of the currents at that period. For some time after they are propelled from the interior of the sponge, they swim about by means of the cilia on their surface, and exhibit all those extraordinary phenomena of spontaneous motion which Cavolini, nearly half a century ago, discovered in the ova of the Gorgonia and Madrepore. They at length fix themselves, like the ova alluded to, on a spot favourable to their growth ; they lose entirely their original form, and become a flat transparent circular film through which horny fibres shoot ; they soon spread, and assume a form similar to that of the parent.\u201d *\nGemmules. \u2014 Mr. Bowerbank has given the following description of the gemmules of Halichondria Johnstonia. \u201c The gemmules of this sponge are dispersed in great abundance throughout every part of its substance ; they are of an oval form, the longest diameter being \u25a0\u00f6^th, and the shortest, the ^^th of an inch. They vary considerably in size, but the above are their average dimensions. When seen by direct light, with a power of 100 linear, they appear of the same colour as the surrounding fleshy matter ; but when viewed as transparent objects they assume an iron or slate-gray colour, having their surfaces closely studded with minute papillae, which are produced by the projection of the points of numerous very small spicula, which are imbedded in the crust or shell of the gemmule, and are disposed in lines radiating from the centre to the circumference of the body.\u201d\nThe form of these minute spicula is exceedingly various ; but the best developed ones appear conical, having their bases towards the centre of the gemmule, and their apices slightly elevating the parts of the outer integument immediately above them. The mode of disposition of these spicula is best observed, when a small portion of the sponge has either been treated with boiling nitric acid, or by incineration in the flame of a lamp. The dissolution of the gemmules is not effected by either of these agents, and, to view them with the greatest effect, they should be gently\n* Edin. Phil. Journ. ; and Edin. New Phil. Joum. vol. ii. p. 128, &c.\ntriturated with a little water between two pieces of glass, until some of them be broken into small pieces. In these fragments, the spicula may be seen in situ, cemented together apparently bv siliceous matter, which appears to abound in the outer integument of the gemmule. Upon measuring some of these minute spicula in situ, Mr. Bowerbank found the average length to be \u00b0fan inch, or about equivalent to the diameter of a disc of human blood, and their average thickness the 2-8TT\u00d6 \u00b0f an inch, so that they are of exceeding minuteness as compared with those found in other parts of the same sponge.\nThe propagation of Tethea is by means of sporules or gemmules generated within the fleshy substance. The sporules, according to Dr. Johnston, resemble the parent\nFig. 73.\na, Oviform bodies found immersed in the parenchyma of Tethea Cranium magnified; b, one of these bodies viewed through the microscope after compression between two plates of glass. (After Johnston.')\nsponge in miniature ; but they have no distinct rind or nucleus, being composed of simple spicula woven together by the albuminous matter ; and there seems no way of escape for them, except by the dissolution of the body of the parent sponge, which most probably is an annual production. \u201c The naturalist *, who believes that sponges have an affinity with the fungi, will see, in these particulars, a correspondency which may strengthen his belief. The Tethea, he may say, is the sea\u2019s copy of the earth-born Scleroderma, and he may remind us that, like the sporules of sponges, the spornles of fungi are equally locomotive. The Chaos fungor um of Linnaeus is thus described : \u2014 \u201c Habitat uti semen Ly-coperdi, Agarici, Boleti, Mucores, reliquorum-que fungorum, in sua matre usque dum disper-gatur et in aqua exclusum vivit et moritur, demurn figitur, et in fungos excrescit. Zoophytorum metaphorphosis \u00e8 Vegetabiliin Animale fungorum, itaque contrario exAnimali in Vegetabile.\u201d \u2014 Syst. p. 1326.\nThe admissibility of sponges into the animal series is, indeed, extremely problematical, and we doubt not that among naturalists of the present day the balance of opinion would be unfavourable towards retaining them in the rank which they at present occupy in zoological classification.\n{T. Rymer Jones.)\n* Johnston, p. 82.","page":70},{"file":"p0071.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t71\nPRODUCTS, ADVENTITIOUS\u2014The difficulty of defining the term Adventitious Product with precision has so frequently been acknowledged, that we feel extremely diffident in offering a new attempt to the consideration of morbid anatomists ; the more so as the recent disclosures of the microscope would probably strike the generality of persons as having, almost of necessity, simplified the task, while they have in reality rather increased its perplexity. Fully conscious, then, of the debatableness of the ground we tread on, we would apply the term Adventitious Product to any substance which, either produced by or developed in connection with the animal frame, - neither forms a natural constituent element, nor a natural secretive product, of the structures amid which it is evolved. The qualification, \u201c either produced by or developed in connection with the animal frame \u201d is required to ensure the exclusion of Foreign Bodies ; and the latter member of that qualification, \u201c developed in connection with the animal frame,\u201d as plainly necessary to ensure the inclusion of Parasites, which (whether they be the proceeds of equivocal generation or evolved from germs introduced from without) are certainly not produced by the textures containing them.\nUnderstood thus, (and the signification seems the widest that can, in a practical point of view, be given to the term,) the character of adventitiousness is conceived to arise in three different ways: \u2014 a substance may, in truth, be adventitious, because its nature is different from that of any of the natural textures and secreted materials ; or because the form it has assumed differs from that under-which it naturally occurs j or because the situation it occupies is one to which such substance is in the natural order of things wholly foreign. Thus tuberculous matter is adventitious, because it differs in nature from all the elementary structures and secretions ;\u2022 a calculus composed of lithate of ammonia is adventitious, because the form, assumed by the salt composing it, differs from that it wears as a constituent of healthy urine ; and an ossification of the pleura is adventitious, because the ossiform structure forming it occupies a locality in which, in the healthy state, bone is unknown.\nThe amount of adventitious quality in products of these three kinds differs : it is greatest and most clearly defined, where dependent on the nature of the constituent material. Thus, in the first place, concerning the adventitiousness of cancer or pus, no doubt can ever arise ; their physical and chemical characters and their essential nature are decisive of the point. In the second place, when a product becomes adventitious sifbply from the peculiarity of its localization, the question is often less clear ; nor indeed can it in the existing state of knowledge be invariably settled. Muscular fibres have, for instance, been met with in the walls of the ureter ; albumen is excreted in great quantity with the urine in certain states of disease: but whether such muscular fibres are to be considered evidences of hypertrophy or ac-\ntual new products, and whether such albumen must be viewed as a totally new material of renal secretion, or as a natural element of urine in excess, depends upon the mode of decision of the preliminary questions, whether rudimentary muscular fibres do or do not naturally exist in the situation referred to, and whether albumen do or do not, in excessively small proportion, form a natural constituent of human urine. And this is not the only aspect under which it becomes practically difficult to distinguish hy-pertrophous from adventitious products. The two states are in some conditions of disease distinctly and intimately associated. Thus, in eburnation of the heads of bones, the proper osseous tissue undergoes hypertrophy only, while the adjacent articular cartilage becomes infiltrated with adventitious bone. Again, the fat, which forms in abundance in the liver in the so-called \u201c fatty degeneration \u201d of that organ, is at first merely an excess of that naturally existing in the hepatic cells, and can therefore only be regarded as a product of unhealthy supersecretion : but with the advance of the morbid change, the inter-cell texture of the organ becomes infiltrated with fat ; and this fat is an adventitious product by reason of the locality it occupies. Nature here, as elsewhere, transgresses the artificial limits established for the facilities of study. In the third place, it is clear that newness ofform implies the quality of adventitiousness in an inferior degree only \u2014 that a material naturally existing dissolved in a secreted fluid, for example, does not, when from physical or chemical causes it accumulates in solid masses, possess the quality in question to the same amount as another which is never, under any shape nor even in the minutest proportion, a natural existence.\nThe great number and variety of the objects to which the term Adventitious Product, defined in the manner we have just proposed, will apply (from a microscopical crystal, for instance, to the highest species of intrinsically vegetative Growths) render it necessary, in limine, to introduce some order into the subject. We shall consequently set out by tracing those lines of distinction which separate from each other the various objects united together by the common property of Adventitiousness.\nIt would, no doubt, be desirable and most strictly logical to employ some one uniform principle in establishing the various divisions and subdivisions of this, as of all other groups of natural objects, which require classification. But in the present state of know ledge, at least, systematic accuracy of this kind is unattainable. Neither the anatomy of texture or of form, the physical or chemical nature or properties of ultimate elements, the mode of formation, the physiological properties, nor the pathological influences of morbid products, will, taken singly, supply a feasible instrument of classification. All must by turns be made to contribute their share in the work. And as all previous modes of arrangement have been found to bear the impress of contemporary physiological doctrines, so will the existing impulse towards micrological study be traced in ours.\nF 4","page":71},{"file":"p0072.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n72\nBut we have not pushed the use of microscopical characters to extremes, persuaded as we are that more has been done to lower than to raise micrology in general estimation by the attempt to make it (in its present unformed state) the essential and sole groundwork of distinction of organized products.\nAdventitious products present themselves in the solid, the liquid, and the gaseous states ; and this difference of molecular condition coincides with so many pathological distinctions, that (although some objections may on \u201c transcendental\u201d grounds be raised to the procedure,) we shall found upon it a division of the whole into three corresponding groups. A complete description of the Morbid Anatomy of the more complex of the species composing these groups should, we conceive,* comprise that of their material or physico-chemical\ncharacters ; of their origin, progress, and decay ; of their intrinsic morbid changes, (for their lives, as the lives of the organism they inhabit, are liable to variations of health and disease, \u2014 they are microcosms within a macrocosm ;) of the textural alterations they produce in contiguous parts ; and of the modifications their existence entails on the solids and fluids of the economy at large. It is clear, however, that a plan so extensive as this could not be ventured on in the present work ; but, as far as is reasonable, we shall pursue it.\nGROUP I.\nSOLID ADVENTITIOUS PRODUCTS.\nThe group, Solid Adventitious Products, resolves itself naturally into two great classes\nClass I_Non-Plastic Products or PRECIPITATES.\nSub-Class I. (Saline.) Produced by precipitation from secreted fluids. Sub-Class II. (Animalized.) Produced by exudation from the vessels.\n\u00a7 I-\nParticles.\n\u00a711.\t\u00c7 A. Calculi.\nL Masses.\t( B. Concretions.\n! \u00a7 I. Protein-Compounds.\n(certain forms of the).\n1 \u00a7 II. Fat.\n\u00a7 III. Sugar.\nClass II. \u2014 Plastic Products or FORMATIONS.\nOrder I. Derived from a blastema which generates cells deficient in vegetative faculty and in permanency.\nDeposits.\nI.\tTyphous Deposit.\nII.\tTuberculous\t\u201e\nIII.\tPurulent\t,,\nIV.\tMelanie\t\u201e\nY. Diptheritic\t\u201e\nSub-Class I. Products possessed of a dependent existence and derived from a Blastema.\nBlas tern al Formations.\nOrder II. Derived from a blastema which generates cells possessed of vegetative / faculty, but deficient in permanency.\nGrowths.\nSub-Order I. Deficient in the power of destroying by infiltration the natural tissues amid which they are evolved.\nNon-Infiltrating Growths.\nSub-Order II. Possessed of the above power. Infiltrating Growths.\n1\nI\nOf Protein-basis.\nOf Fat-basis.\nOf Gelatin-basis.\nOf undetermined basis.\nI\n1\nH\u00e6matoma.\nSarcoma.\nCystoma.\nAngeiectoma.\nMelanoma ? ?\nLipoma.\nSteatoma.\nCholesteatoma.\nFibroma.\nEnchondroma.\nOsteoma.\nJ Colloma.\nProteS-basis. } Carcinoma.\nSub-Order I. Sui generis.\n}\nInduration-matter.\nOrder III. Derived from a blastema which generates cells deficient in vegetative faculty, but possessed ofy>er-manency.\nPseudo- Tissues.\n-\nSub-Order II. Simulating the natural tissues of the adult.\nSub-Class II. Products possessed of independent existence and derived from a Germ.\nGerm-Formations or Parasites.\nOrder I. Animal.\nOrder II. Vegetable.\n[\n{\nEntozoi.\nEpizoa.\nEntophyta.\nEpiphyta.\nExtra-Vascular.\n{\nSimple-Vascular.\ni\ns\nCompound-Vascular <!\nI\nEpithelium.\nNail ; Hair.\nCartilage.\nCellular ; Serous.\nFibrous ; Elastic.\nOsseous.\nNervous.\nBloodvessel ; Erectile tissue. Lymph-vessel..\nFibro and Spongy Cartilage. Bone; Tooth.\nCutaneous ; Mucous. Glandular.\nMuscular.\n* Vide Introductory Lecture, Lancet, 1842.","page":72},{"file":"p0073.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t73\nvas exhibited in the annexed table), those of non-plastic and plastic compounds. The dass of non-plastic compounds includes those formed of matter chemically inorganic, and also those which, though organic in a chemical point of view and animalized,yet are completely destitute of structure (for example, animal sugar, cystin, xanthin), and, consequently, in respect of physiological attributes, almost take rank with minerals. The class of plastic compounds comprehends all such as present in any degree,be it ever so rudimentary, the characters of structure. A distinction so broad as the absence or presence of structure might, \u00e0 priori, be affirmed to form a natural basis of classification ; and, as will be seen, products belonging to the two classes do absolutely differ in all essential particulars of their physiology and pathology.\nClass I.\u2014Non-plastic Products.\nProducts of this class are composed of materials either (first) completely inorganic ; or (secondly) of elements, though organic, incapable of assuming organized arrangement ; or (thirdly) they are formed of a union of substances of both these kinds. Of the first variety one of the most unquestionable examples is supplied by solid accumulations of calcareous salts round inorganic bodies introduced into the system from without. To the scond belong biliary calculi,\u2014masses composed mainly of an animal substance not only unfitted to form structure, but lowered in the scale of animal existences by having a crystalline form impressed on it. Among the products belonging to the third variety may be found, for example, certain urinary calculi, compounds of inorganic saline, and structureless animal, substances.\nAll non-plastic products agree in being directly derived from the fluids of the body. But they are not all developed on a uniform plan. Some of them originate in the coalescence of the more solid particles of secreted fluids, after the act of secretion is accomplished ; and this coalescence is essentially a physicochemical process, primarily, of precipitation, and, secondarily, either of crystallization or accretion. Others are exuded ready formed from the vessels. And this difference in mode of origin coincides with numerous differences in pathological relations; hence it may be advantageously used in forming two sub-classes of non-plastic products ; those (Sub-Class I.) : Produced by precipitation from secreted fluids.\n(Sub-Class II.) : Exuded ready formed from the vessels.\nSUB-CLASS I. \u2014 SALINE PRECIPITATES.\nThe various secreted fluids may be regarded as saline solutions, in which the proportion of menstruum and of dissolved salts is chemically accurate. If any cause affect this proportion in such manner as to lower the ratio of solvent fluid, precipitation of the solid matter must follow ; or if some new substance be introduced\nwhich changes the chemical relations of the dissolved and dissolving materials, a similar result necessarily ensues. The alteration of ratio referred to may obviously arise either from diminution of the solvent, or increase of the solid, material. Thelatter of these states exists at the moment of secretion ; the former may either exist then, or be induced subsequently to the act of secretion (inconsequence generally of unnatural stagnation of the fluid in its excretory passages) by evaporation, by absorption, possibly by exosmosis, and other agencies.\nBut embracing in one view all the saline products found in the body, nothing can be more certain than that a primary modification in the qualities of the secretions themselves is the main agent in their generation. No point in general pathology affords matter of more curious inquiry than the causation of these changes in the character of the secretions. If in some cases observation teaches us to refer them to a local morbid power, limited in duration as in the extent of surface it implicates, in other and much more numerous instances they may be traced to the operation of a constitutional influence, itself dependent on diet, mode of life, climate, &c.\nProducts belonging to this sub-class present themselves in the form of\n$ 1. Crystalline or amorphous particles ;\n\u00a7 2. Masses.\n\u00ff 1. Crystalline or amorphous particles.\u2014 Although in the great majority of cases these particles are, as just explained, simple inorganic precipitates from the secretions, yet recent inquiries have distinctly shown that they are in some instances associated with organic matter, which retains the form of the saline particles after these have been dissolved away by acids. Now in respect of the mode of association of the inorganic and organic materials under these circumstances, there are three possible cases. (1.) The organic matter may simply adhere to the surface of the saline ingredients. (2.) Salts of crystalline form may lie in the interior of an organic cell, closely embraced by its wall. Otoliths are each of them, as shown by Krieger*, enclosed in a membranous vesicle. (3.) What appears to be the crystalline form of the saline matter .may, in truth, be simply an accidental result of its association with organic particles, to which the form observed in reality belongs.\nCrystallisation of inorganic matter arises in the human body under various conditions,\u2014 either after death or during life ; and in the latter case as a natural occurrence, or as a morbid phenomenon. Crystals of these kinds are microscopical objects.\nThe faeces contain crystals naturally ; in typhoid fever with morbid change in Peyer\u2019s glauds, crystals appear to form in much greater abundance than under any other circumstances : in this disease, too, they are found heaped up near the implicated glands, instead of being scattered through the contents of the bowel ; and are said, unlike those of ordinary\n* De Otolithis, p. 15.","page":73},{"file":"p0074.txt","language":"en","ocr_en":"74\nPRODUCTS, ADVENTITIOUS.\nf\u00e6ces, to be readily soluble in sulphuric and hydrochloric acids without effervescence.\nCrystals discoverable during life in connection with acknowledged states of disease may be provisionally arranged as follows : \u2014\nCrystals forming in\n(a), Natural secretions and excretions altered in properties\n(\u00a3), Products of inflammation ..........\n(c)\t, Specific fluids of\n(d)\t, Adventitious Formations...............\nUrine,\nF\u00e6ces, &c.\nPlastic 1 exuciat;ons\nSerous j\nPus,\nGangrenous products, Catarrhal discharges. Vaccinia,\nVariola,\nSyphilis,\nGlanders.\nCancer,\nAcephalocysts, &c.\nOf the natural secretions which (in consequence of alteration in their composition) are liable to contain saline matters in the form of minute crystals, the urine is by far the most important. With the strictly crystalline variety may be associated certain amorphous pulverulent precipitates. These products occur in the urine in the form of pellicle, cloud, or sediment ; in other words, they form a thin stratum on the surface of the fluid, float between the upper and lower surfaces, or gravitateFo the bottom of the containing vessel. These varying positions, appreciable to the naked eye, aid the observer in forming a rough estimate of the nature of the saline matter, and may be almost conclusive on the point. The microscopical and chemical characters combined supply, however, the real evidence from which their composition is ascertained* ; in order to avoid repetition, we will defer the consideration of these characters until engaged with the subject of urinary calculi. We shall have occasion to recur, in describing the morbid substances (b, c, d), referred to in the above classification, to the appearance of crystals within them. But it may be stated here, as a general fact, that as the materials of all such crystals exist primarily in solution, and as absorption, evaporation, or chemical appropriation of water leads to their deposition in the crystalline form, there is a source of fallacy in the examination of preparations kept in spirits ; certain salts, combined with the aqueous part of the material examined, are deprived of their water by the alcohol, and separate in crystalline forms.\n$ 2. Masses. \u2014 Adventitious products belonging to the present sub-class, and possessing sufficient bulk to be called masses, form\n* As the majority of the substances included under the present head enter (though comparatively in small quantity) into the composition of healthy urine, it is necessary to observe that they, practically speaking, acquire the character of adventitious products through the new form they assume, when the proportion in which they accumulate increases.\nan important group, divisible into two series differing from each other in a variety of important natural characters. Some of them are, in truth, composed wholly or essentially of saline or other non-plastic materials, precipitated from the fluids of the system ; others of similar materials, deposited in an adventitious basis, itself stromal or non-stromal. In the first series, the non-plastic compounds form the essential, if not the whole, \u201c materies morbi;\u201d in the second, these compounds are merely superadded to pre-existing matter (commonly morbid) of another kind ; and such superaddition, instead of increasing the activity of functional disturbance in the system, tends frequently to weaken the destructive influence of that pre-existing matter. For the sake of convenience, bodies belonging to the first series may be termed true calculi, or simply calculi; to the second, pseudo-calculi, or concretions.\n(A) Calculi. \u2014 True calculi, answering to the definition just laid down, may be deposited from almost all the secreted fluids. But of these fluids, the urine is, perhaps, the only one of which the saline and other actual constituents, independently of any materials naturally foreign to their composition, form the substance of calculi ; when calculous formations occur in other secretions, foreign ingredients may almost invariably be detected. The saline substance thus met with in calculous masses, and which does not enter naturally into the composition of the secretion, (or enters in excessively small proportion,) is most commonly the phosphate of lime. So frequent is the occurrence of this salt in calculous masses on mucous surfaces, as to lead irresistibly to the conclusion that mucous membrane has a specific tendency to secrete this salt, under certain conditions of local irritation.\n(a) Urinary calculi. \u2014 Various constituents of the urine are capable of accumulating individually, or in association with each other and with certain animal substances, (mucus, fibrin, albumen, fatty matters, colouring matters, &c.,) so as to form masses of variable form and size ; these masses are according to their bulk termed calculi, miliary calculi, and gravel. The same materials unaggregated into masses form the substance of sediments, clouds, and pellicles. The following are the substances which to various amounts have been recognized as the constituents of urinary calculi : uric acid, urates of ammonia, of soda, of magnesia and of lime, oxalate and benzoate or hippurate of ammonia*, oxalate of lime, xanthin or uric oxide, cystin, phosphate (neutral and basic) of lime, triple phosphate of ammonia and magnesia, carbonate of lime, carbonate of magnesia, silica, peroxide of iron, fat, extractive matter, colouring matters, fibrin, albumen, and mucus.\nThe coalescence of the component parts of urinary calculi is effected in three chief ways.\n* Simon remarks that the presence of the benzoate, as recorded by Brugnatelli, and of the oxalate, as described by Devergie, is scarcely compatible with the great solubility of those salts.","page":74},{"file":"p0075.txt","language":"en","ocr_en":"1. When the materials forming them are crystalline, minute crystals, the basis of the future calculus, go on increasing in number, though not individually in size, and by their accretion, depending upon mutual attraction, form masses. Animal matter may aid in cementing together the constituent parts, but in this form of coalescence its occurrence to any amount is accidental, and tends rather to diminish the firmness of union. Pure uric acid calculi are formed on this model. 2. When the substance forming calculi is primitively amorphous, no attraction exists between the minute particles forming the deposit ; hence a medium of union or cement is necessary. This is furnished by animal matters secreted with the urine, or thrown out by the surfaces along which it passes. The quantity and quality of these matters being liable to vary, the general aspect of the resulting calculus, and its properties of density, &c., must be subject to similar variety. Impure urate of ammonia calculi illustrate this mode of formation. 3. In the third species of aggregation, saline particles in a semi-liquid state form a sort of thick magma, as particularly insisted on by M. Civiale * ; the condensation of this magma produces a uniform mass, or small spherical bodies, or simply a pulverulent matter. This mode of formation is chiefly observed in oxalate of lime calculi, but occurs also in the uric acid species mixed with various salts (e.g. in a calculus in the University College Collection composed of uric acid, urate of ammonia, triple phosphate and phosphate of lime), and in the phosphatic.\nThe first deposition of matter from the urine in these cases depends upon some one or more of the causes we have already enumerated in speaking of the precipitation of the saline constituents of secreted fluids generally.\nIf this matter be not expelled from the body, it acts in various ways as a source of further deposition and accumulation around itself ; it is for this reason called tY\\enucleus,ax\\d the matter accumulated around it the cortex, of the entire mass. Every calculus may hence be theoretically resolved into a nucleus and cortex ; but it is not the practice to give the central part the former name, unless it be distinctly different in composition, or, at least, in aspect, from the matter immediately investing it ; there are, therefore, practically speaking, non-nuclear calculi, of which the pure uric acid and cystin species furnish examples.\nThe nucleus of a urinary calculus, although commonly formed of sedimentary saline matter, may likewise consist of various materials not naturally existing in the urine, and these materials may be either formed in the body or introduced from without.\nFirst : sedimentary nuclei may be composed\n* Trait\u00e9 de l\u2019Affection Calculeuse.\nPRODUCTS, ADVENTITIOUS.\t75\nof any one of the more important materials (with perhaps a single exception) detected in urinary calculi ; of these uric acid and oxalate of lime are the most common, while the phosphate of lime and triple phosphate hold the opposite position in the scale. A law established by Dr. Prout, that \u201c a decided deposition of the mixed phosphates is not followed by other depositions,\u201d is, with few exceptions, universal. Cystin has not (as far as we are aware) been found playing the part of a nucleus in any recorded case ; to this statement a large calculus of cystin surrounded with a very thin coating of phosphates (Univ. Coll. Museum) cannot fairly be considered to supply an exception.\nA calculus commonly contains a single nucleus only ; but instances are not wanting of calculi containing two, three, and more nuclei. Masses of the latter kind are probably simply aggregations of smaller ones, as appears to have been the case with that exhibited in^g. 74.\nFig. 74.\nCalculus with \u201c double nucleus,\u201d probably a double calculus. {Univ. Col. Mus.')\nThe mode of connection of the nucleus and cortex varies. (1.) The union may be intimate and general by every point of the apposed surfaces ; this is the most common case ; (2.) the nucleus may adhere to the cortex by asperities on its surface only ; empty spaces, or spaces filled with grey gritty matter, being interposed between them : (3.) the nucleus may be free in the centre of the mass. Of the latter rare state a striking specimen exists in University College Museum ; the surface of the nucleus is covered with dark-coloured matter in powder (dried and altered blood), some of which helps to fill the cavity existing between the nucleus and cortex.\nThe nucleus (when of the present species) is generally the hardest part of a calculus. It forms either in the kidney, or, much more rarely, in the bladder.\nSecondly : animal matter, having such characters as render it impossible, according to Berzelius, to determine whether it is composed of mucus or of albumino-fibrinous substance,","page":75},{"file":"p0076.txt","language":"en","ocr_en":"76\tPRODUCTS, ADVENTITIOUS.\nalmost constantly occurs in calculi, and sometimes forms the nucleus of a mass. Howship has figured a remarkable specimen, voided from the urethra of a negress, in which the nucleus consisted of \u201cmucus,\u201d associated with a very little phosphate of lime,\u2014the cortex of more solid phosphates. Clots of blood occasionally form the central part of calculi ; a fact noticed first by Fr\u00e8re C\u00f4me.\nThirdly: foreign bodies, introduced from without, not very unfrequently constitute the nuclei of urinary calculi. In the great majority of cases these bodies are directly pushed into the bladder ; but in some well-authenticated cases have reached that viscus after having been swallowed or otherwise introduced. Among bodies acting as nuclei have been met pins (Univ. Coll. Mus.), needles, tooth-picks, ear-picks, pieces of wood, stems of plants, ears of corn, grains of corn, stones of various fruits, tubes of various kinds, glass or earthen, &c., pieces of bougies and catheters, balls and other metallic bodies, a globule of mercury,* pebbles, &c. When the bodies thus introduced are sharp, as pins, they sometimes protrude beyond the calculous matter, and (a fact surgically important), are fixed in the surrounding tissues.\nInstead of a nucleus the centre of a calculus may present one or more cavities of variable size and shape, almost invariably lined with a black pulverulent or laminar matter, and sometimes containing powdery substance; in other instances, there is neither surrounding nor contained matter of this kind. It has been supposed that in all these cases an original vegetable or animal nucleus had been gradually removed by a process of decomposition and subsequent filtration through chinks in the cortex.\nThe prominent physical characters of the cortices of calculi divide them into two natural classes ; the (a) granular or irregular, and the (h) laminated,\n(a)\tOf granular calculi the best example is supplied by oxalate of lime, but the appearance of these masses is not always identical. Sometimes the mass looks homogeneous and non-granular, manifestly from the close aggregation of the original granules. In the more ordinary cases the granules remain distinct, whence the well-known tuberculated or mulberry-like aspect. Uric acid calculi, rendered impure by association of certain saline matters, assume the granular form ; the phosphates are sometimes granular; and the pulverulent character of the fusible calculus allies it to this species.\n(b)\tIn laminated calculi the cortex is, as the\n* See Malago, in Filiatre Sibezio, 1845 ; or Simon\u2019s Chemistry, by Day, vol. ii. p. 440. In the University College Collection is a triple phosphate calculus, having the tibia of a foetus for its nucleus. The pregnancy had been Fallopian, and ulceration having occurred between the adherent tube and the bladder, the tibia (with probably other portions of the skeleton subsequently otherwise disposed of,) made its way into the latter organ, and became encrusted abundantly with phosphates. The calculus, presented to the College by Mr. Liston, was given to him by Dr. D. It. Lietch.\nword implies, composed of successive layers. Although each layer may and generally does differ in thickness from others, its own thickness at its different parts may be said to be commonly pretty uniform ; nevertheless to this there are exceptions, and it is manifest that whenever the cause of accretion is in greater activity towards one aspect of a calculus than another, there the lamina in course of deposition must be thicker than elsewhere. Now in conformity with a general principle already laid down, we should expect the phosphates, which are formed in consequence of local irritation in particular places, to furnish the most frequent instances of irregular thickness ; and such is in truth the fact, though, as is proved by the annexed cut (fig. 75), not always so.\nFig. 75.\nOxalate of lime nucleus; the cortex (circular and conoid parts') impure uric acid. ( U. C. Museum \u2022 patient of Mr. Quain.) The spherical part was probably seated in a succulus.\nThe mode of union of the lamin\u00e6 differs ; it may be so intimate that the line of separation is lost at certain points of the apposed surfaces ; in other cases the union is imperfect and loose, and interspaces of some width are left between those surfaces.\nThe section of a laminated calculus is sometimes marked by lines radiating from the centre to the periphery, cutting the laminae into segments of unequal size. This is obvious in certain cystin calculi, in some of uric acid, and in many of the mulberry species.\nThe tint of the different strata of a calculus, composed essentially of one substance, is not always the same throughout ; nor are strata, the same in composition and separated by materials of other kinds, generally of the same hue. These varieties must depend upon irregular admixture of impurities.\nCalculi composed, at least essentially, of a Fig. 76.\nAlternating calculus of uric acid and [?] triple phosphate. ( University College Museum.)","page":76},{"file":"p0077.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nsingle substance, are termed simple ; of several, compound. When the different materials are applied in successive laminae, the calculus is said to be alternating (fig. 76) ; when they are irregularly mingled it is called mixed. The relative frequency of the three kinds may be deduced as follows from tables printed by Dr. Prout. Of 1520 calculi there were\nSimple, 709 ; Alternating, 787 ; Mixed 24.\nThe mode of succession of various substances in the formation of alternating calculi (they may consist of two, three, four, or several successive strata), is pathologically important, and has been specially investigated by Dr. Prout. The nature of this work prevents us from entering into the subject, but we may mention (as evidence of the generality of Dr. Prout\u2019s law, that the existence of mixed phosphates in a calculus excludes the subsequent deposition of other matter), that of 566 alternating calculi composed of two layers, two only were examples of a nucleus of phosphates with a cortex of another kind of salt ; that of 172 calculi formed of three layers, not one had a phosphatic nucleus, and in only three was the middle stratum composed of phosphates ; and that, lastly, of 25 calculi containing four distinct layers, not one had a nucleus of phosphates ; in one only was the second layer, and in three only was the third layer, thus composed. It is, however, right to observe that if small quantities of phosphates, not forming actual layers, were taken into consideration, the exceptions to the law would be much more numerous.\nThe degree of rapidity with which calculi form and acquire bulk depends upon the constitutional condition of the individual in whom they form, much more than upon the nature of their own ingredients ; for, if it be true that oxalate of lime and uric acid calculi commonly enlarge slowly, and the phosphatic species with great quickness, instances of the direct contrary are far from uncommon. The cases in which calculous matter accumulates round a foreign body are obviously those, and those alone, in which perfect accuracy as to dates can be obtained ; now cases are on record showing that some weeks suffice in one case for as abundant accumulation of phosphates as several months in another. The slower the enlargement, the greater, c\u0153teris paribus, the density of the mass. In this latter quality calculi vary exceedingly, some being as remarkable for their porousness and openness of texture, as others for their compactness and closeness. Their specific gravity, according to Fourcroy, varies from 1213 to 1976, water being 1000 ; Scharling found it in one instance to amount to 2014.\nCalculi are commonly solitary ; from some calculations, which have been made on a limited scale, it would appear, however, that in one of every five or six cases of calculous disease two or more calculi are met with. The number and size of these bodies discovered in the bladder are sometimes almost marvellous ; thus Rodrigue de Fonseca refers to a case in which that viscus contained fifty as large as nuts ; fifty-\n77\nnine were found in Buffon\u2019s bladder ; and Moraud counted six hundred and seventy-eight in the bladder of an old man, and nearly ten thousand in his kidneys. Probably miliary calculi only accumulate in such extraordinarily great numbers.\nWe shall now briefly consider the physical and chemical characters of each calculus in particular, \u2014 appending in each instance an outline of the qualities of its component material, when occurring in the form of urinary sediment.\n1. The uric acid calculus is generally of oval shape and somewhat flattened, ranges in weight from a grain to six or seven ounces and upwards, and varies in size within corresponding limits ; the calculus, from a section of which the subjoined cut is reduced, measures 2-f inches in breadth and 3f inches in length. The\nFig. 77.\nSection of an uric acid calculus. ( Univ. Coll. Museum.')\nexternal surface, commonly smooth, may be finely granular, and its colour brown of different tints and depths, unless it have received a thin coating of phosphates. On section it is generally found to be laminated, and when comparatively pure its fracture has a crystalline look ; when the contrary, the appearance is that of aggregated amorphous particles ; the general colour is that of the external surface (much impurity may, however, render it gray or otherwise alter it), but the different strata may vary very considerably in depth of hue from yellowish-brown to mahogany colour, according to the amount of colouring matter present in each ; its density is high in the direct ratio of its purity. Absolute purity never exists ; all uric acid calculi contain colouring, and, with rare exceptions, fatty matters, some mucus or albumen, and besides, minute quantities of urate of ammonia, of soda, and of potash, with occasionally carbonate and phosphate of lime.\nIn 251 of the 763 alternating calculi, the composition of which is given by Dr. Prout, the nucleus consisted of uric acid.\nUric acid occurs as an ingredient of urinary sediments, and although not, as Berzelius supposed, their chief material in persons in health, (the amorphous urates vastly exceed it in abundance,) it may in cases of gout form the entire of the deposit.\nUnder the microscope uric acid appears in the form of semi-transparent, thin rhomboidal scales, of slightly yellow tinge, generally, from impurity (the pure acid being brilliantly white),","page":77},{"file":"p0078.txt","language":"en","ocr_en":"78\nPRODUCTS, ADVENTITIOUS.\ninsoluble in cold and hot urine and in weak acids, soluble with effervescence (from equal volumes of carbonic acid and nitrogen) in concentrated nitric acid, the mixture acquiring a purple red hue (from murexide) at the close of evaporation, and very sparingly soluble in concentrated muriatic acid. (See fig. 78, a.')\nCrystals of uric acid.\nSometimes (and less rarely than has been supposed) the rhomboidal prisms are thick, solidlooking, and cuboid in appearance. We have lately seen a pe//i^(non-irridescent) of bloody urine after scarlatina formed of crystals of this kind (fig. 78, b). Sometimes, again, fragments of, or entire, crystals unite so as to form lanceolate or stellate figures ; this form may be produced (as shown by Rayer, fig. 78, c) by artificial precipitation.\n2. The urate of ammonia calculus (of which the existence was denied by Mr.Brande, on the plea that the ammonia evolved from certain calculi is in reality derived from associated triple phosphate, or from urea and the ammoniacal salts of the urine,) is said by Fourcroy and Prout to be rare, and more frequent in children than in adults, a statement which has been copied by various writers. The tables collected by Dr. Prout show that of 709 simple calculi 59 were composed of urate of ammonia nearly pure, 159 mainly of this salt mixed with variable proportions of the urate and oxalate of lime and phosphates. The shape of this calculus is more irregular than that of uric acid masses, but still inclined to the ovoid ; it does not reach any large size, and has a smooth or granular surface. Internally it is laminated; of clay colour ; its fracture earthy, and its density considerably less than that of lithic acid. Of 163 alternating* calculi grouped in Dr. Prout\u2019s tables we find that 239 had a nucleus of pure urate of ammonia. In the majority of cases, then, this salt or uric acid forms the groundwork of calculous accumulation ; for they constitute either the entire mass, or the nucleus, of 938 among 1473 calculi of ascertained composition in the following proportions, exclusive of many others in which they were mixed irregularly with other saline matters.\nCalculus. Nucleus.\nUric acid,........ 230\t251\nUrate of ammonia\"!\tgis\t239\npure and impure J\n448\t490\n938, or 1 in 1-6\nUrate of ammonia is the chief constituent of the pulverulent sediments of urine voided by healthy persons : it is insoluble in cold, soluble in hot, urine. It is commonly distinguished microscopically as a pulverulent closely packed matter (fig. 79, a) ; in other instances it wears the form of globules of black colour # (fig. 79, b) ; when alkaline reaction is established (or sometimes, as we have seen, while the urine is still acid) these globules become stellate from the formation of minute silky needles apparently springing from their circumference (fig. 79, c).\nFig. 79.\na, b, c, Deposits of lithate of ammonia, (Afterflayer.')\nTreated by dilute nitric acid, the pulverulent matter is converted into rhomboidal crystals of uric ac\\d,fig. 78. Collected on a filter and washed with rectified alcohol, the residue of the amorphous matter, treated with potassa, disengages ammonia, to be detected by the smell, test paper, and hydrochloric acid. The forms b and c cannot be confounded with any other substance ; the pulverulent form might be mistaken for phosphate of lime, and the modes of distinguishing the two precipitates are explained with the description of the latter. The forms b and c (first described by Quevenne) we have repeatedly observed in the sediment of urine containing lithates in abundance. Though mainly composed of urate of ammonia, the acid is apparently in union also with potass, soda, lime, and magnesia. Quevenne considers that they may in some sort be regarded as products of putrefaction, as they do not appear until the urine has stood for about three days ; but this is decidedly erroneous, as we have repeatedly seen the simple globular, and sometimes the stellate globular, forms in urine which had not stood twenty-four hours.\n3. The oxalate of lime calculus is generally more or less accurately spherical in shape ; though commonly of rather small or moderate size, it may acquire very considerable bulk : a model of a mulberry calculus, now before us, (Univ. Coll. Museum) measures 7f inches in circumference, and some of the prominences on the surface reach five lines in height. Of dark brown, purplish, blackish, or olive colour, this\n* This form, which we are in the habit of familiarly calling the \u201c globular lithate,\u201d is not exceedingly uncommon. In the numerous instances in * which we have met with it, we have, however, failed in ascertaining the particular condition regulating its occurrence.","page":78},{"file":"p0079.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n79\nspecies of calculus is remarkable for the\u2019rough tuberculated character of its surface, which gives it the aspect of a mulberry. Its section exhibits commonly a granular, but sometimes a laminated, arrangement; the internal colour is the same as the external ; the density and hardness (especially of the laminated variety) vary considerably. The dark colour of these calculi is generally ascribed to admixture of the colouring matter of blood, thrown out from the irritation their rough surface produces on the tissues it comes in contact with. The oxalate of lime calculus may occur of pure white colour, with sharp angular crystals on the surface ; of this rare variety the University College Collection contains a remarkable specimen.\nThe rarity of oxalate of lime crystals in urinary deposits was matter of received opinion until the inquiries of Dr. G. Bird led him to the inference that in the cases of disease occurring in London . . . the oxalate of lime is of far more frequent occurrence in urine than the deposits of earthy phosphates.* The oxalate deposit, when in abundance, appears to the naked eye, after the application of gentle heat, as a white glistening powder, which under a low magnifying power resolves itself into \u201c crystals of the oxalate in beautifully formed transparent octohedra,with sharply defined edges and angles {fig. 80, a). It sometimes happens that\nFig. 80.\nthe oxalate is present in the form of exceedingly minute crystals ; it then resembles a series of minute cubes, often adhering together like blood-discs : these, however, are readily and distinctly resolved into octohedra under a higher magnifying power. If the crystals be collected and ignited on platinum foil, oxalic acid is decomposed and carbonate of lime left : the subsequent addition of dilute nitric acid dissolves the residue with effervescence.\u201d The crystals are insoluble in boiling acetic acid or liquor potass\u00e6.\nDr. Bird describes certain dumb-bell shaped crystals {fig. 80, b) with finely striated surfaces, as a variety of form of oxalate of lime. We have frequently seen such bodies, but cannot regard their chemical nature as established.\nFrom a table, which we have drawn up from the daily record of 84 unselected cases (42 of each sex) in our wards at University College Hospital, the following inferences may be drawn\n* On Urinary Deposits, p. 123. 1844.\nconcerning oxalate of lime crystals. They (octahedral form) are of somewhat more frequent occurrence in females (14 of 42) than in males (11 of 42). They are most frequently present in acute affections and in anaemia ; and at that period of acute affections when anaemia is most likely to be fully developed, at the onset of convalescence. They occur in spermatorrhea temporarily. Their frequency in rheumatism has been exaggerated, our proportion being only 3 of 15 cases. They are not present in all cases of any given disease, and probably originate in some special condition of the blood. Observation continues to exhibit to us the frequency of a deposit of oxalate of lime crystals, at the period of convalescence of acute diseases ; so much so that we regard their sudden appearance in an acute disease as a sign of that fortunate change. This deposit is of temporary (say a few days) duration, and not to be confounded with the more or less permanent condition appertaining to a peculiar diathesis.\n4. Of the cyslin or cystic oxide calculus there are two varieties, physically considered; and the physical peculiarities are probably referable to chemical differences. The pure cystin calculus is of oval shape, acquires moderate size ; its surface, tolerably smooth, has a crystallised aspect. Internally it appears formed of a multitude of irregularly aggregated crystals, with their edges rounded off and has the colour and shining look of bees\u2019-wax fig. 81). Small portions broken off are semitransparent ; an ammoniacal solution gives thin lamellar hexagonal crystals by evaporation.\nFig. 81.\nPure cystin calculus, (long diameter nearly 24 inches, short ditto If.) Univ. Coll. Mus. a, externa] surface ; b, section.\nForeign to the natural constitution of the urine, cystin is of very rare occurrence as a morbid precipitate. It appears as a pale nearly white pulverulent matter, insoluble in water,","page":79},{"file":"p0080.txt","language":"en","ocr_en":"80\nPRODUCTS, ADVENTITIOUS.\nin urine (cold and hot), and in acetic acid. It is soluble in ammonia, from which solution it may be obtained by evaporation in the peculiar crystalline form {fig. 82), visible with the microscope only. Cystin is soluble without effervescence in nitric acid ; from this solution silky crystals of aciculated shape and brilliant white colour may be obtained by evaporation. Treated with nitrate of potass, the sulphur (26 per 100 nearly) contained in the cystin passes to the state of sulphuric acid, discoverable by a salt of baryta. Cystin exhales a peculiar phosphorus-like odour when burned on platina.\nThe crystalline form of cystin is the hexagonal prism ; the crystal is transparent, more or less regular, and varies considerably in size {fig. 82).\nFig. 82.\nCrystals of cystin : some are of much larger'size than those represented.\n5.\tThe phosphate of ammonia and magnesia calculus (triple phosphate) is generally of oval or rounded shape, but may be of irregular form ; when constituting the entire substance of a calculus (which is rare), it is of small size usually ; its external colour is whitish ; its surface uneven and crystalline. Internally it is generally granular and opaque, though occasionally laminated and somewhat transparent ; in the former case of porous texture, in the latter compact and dense, and of dirty white colour.\n6.\tThe neutral phosphate of lime calculus, remarkable for the smoothness of its exterior, is of pale brown colour, moderate size, and great rarity, \u2014 so much so that to the chance experience of Dr. Wollaston almost alone are we indebted for what is known of its characters. It is composed of lamin\u00e6, easily separable from each other, and striped transversely.\n7.\tThe phosphate of ammonia and magnesia and phosphate of lime {mixed phosphates or fusible) calculus is of irregular shape, often of large size, white colour, and roughish surface. In the majority of cases its section looks like a piece of chalk of loose texture, being homogeneous, non-laminated, and minutely porous ; in other instances it is lamellar, and between the lamin\u00e6 minute shining crystals of triple phosphate may often be detected. It marks the fingers or other bodies like chalk.\nPhosphoric acid exists in healthy urine in combination with ammonia and magnesia, in such proportion as to form a perfectly soluble salt. If the proportion of base increases, the salt becomes insoluble, and, according to the amount of excess, is deposited either as the neutral or a bibasic triple phosphate.\nThe neutral phosphate of ammonia and magnesia (the only one observed in urine at the moment of emission) occurs in white transparent crystals of perfectly regular forms, referable to the right rectangular prism {fig. 83).\nNeutral phosphate of ammonia and magnesia ; crystals of spontaneous formation.\nThese crystals are often mixed with amorphous powder, commonly composed of phosphate of lime, rarely of urate of ammonia. They are instantaneous^ soluble in weak acids, and the solution is pr\u00e9cipitable by ammonia in the form of the bibasic phosphate.\nThe bibasic phosphate of ammonia and magnesia does not appear to exist in urine, even the most strongly alkaline, at the moment of emission. But its crystals are developed with the progress of decomposition, and may be obtained from any urine by rapidly adding large quantities of ammonia. Microscopically {fig. 84) these crystals appear aciculated and grouped at angles of 60\u00b0, so as to resemble a pinnate or bipinnate leaf.\nFig. 84.\nBibasic phosphate of ammonia and magnesia.\nPhosphate of lime occurs as an amorphous powder ; very soluble in acids, it does not effervesce under their action, like the urate of ammonia, nor, like that salt, furnish crystals of uric acid under the same circumstances ; when the phosphate has been dissolved in an acid, ammonia precipitates a white amorphous mass from the solution.\n8.\tThe xanthic oxide. {uric oxide, xanthin, urous acid) calculus is of extreme rarity ; four examples only (analysed by Marcet, Laugier, Stromeyer, and Dulk,) have as yet been met with. The external surface is described as smooth and polished, and of light brown colour. Some fragments of the calculus analysed by Stromeyer are preserved in the University College Collection ; their fracture is sharp, their colour pinkish brown ; they are composed apparently of easily separable concentric lamin\u00e6, and are very hard ; they become waxy-looking when rubbed. Marcet\u2019s specimen weighed 8 grains, that of Stromeyer 338 grains, that of Dulk 7 grains ; those examined by Laugier were very small. In Dulk\u2019s case","page":80},{"file":"p0081.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t81\nthe oxide formed the cortex of a uric acid nucleus ; in the others it was the sole ingredient. Unger has discovered minute traces of a substance which he considers closely allied to, if not identical with, xanthin in guano : its precise chemical relations, however, appear to be as yet not fully determined.\nObservations are wanting concerning the characters of uric oxide sediments : Berzelius says they are pulverulent and grey.\n9.\tThe carbonate of lime calculus, very rare in man, is not uncommon in graminivorous animals. Dr. Prout has seen some small calculi from the human subject consisting of this salt, of perfectly white colour and very friable. The carbonate may, however, be impure, and the mass accordingly vary in colour from yellow to brown and red. This species has been observed by Smith with the appearance of a mulberry calculus*, by Brugnatelli, Fromm-herz, Walther, Loir, and others. Wood f has described two of pearly, and Rampold If one of metallic lustre.\n10.\tCarbonate of magnesia, according to Berzelius, very probably exists in all calculi composed of carbonate of lime. It appears to have been actually detected in two instances only,\u2014once by Moscati, once by Lindbergson.\n11.\tUrate of magnesia has been found forming the chief mass of two calculi by Scharling; urate of ammonia w7as likewise present.\n12.\tUrates of soda, potassa, and lime, never form the entire mass of a calculus. The former was found in large quantity by Lindbergson in the calculus just referred to. It is uncertain whether urate of soda exists naturally in the urine ; it occurs in association with uric acid and urate of ammonia in sediments, as already mentioned.\n13.\tPhosphate of magnesia is, according to Brugnatelli, of common occurrence, either mixed with triple phosphate, or forming alternate layers with it.\n14.\tChloride of sodium never forms the substance of calculi, and the conditions under which this salt crystallizes in the urine are not w'ell ascertained : partial evaporation of the fluid must first take place. The crystals are octahedral, and have their planes indented like steps of stairs.\nThe nature of the so-called fibrinous calculus (originally described by Dr. Marcet) has been made matter of question by Berzelius. It appears that the material supposed to be fibrin by that analyst was soluble, though not readily so, in nitric acid,\u2014a character not belonging to either fibrin or albumen. This, with other of its properties as detailed by Marcet, leads Berzelius to regard the matter as inspissated vesical mucus.\nThe Museum of University College contains a \u201cfibrinous calculus\u201d taken from the bladder of a cow (fig. 85). It is of irregular elongated shape, measuring two and a half by one and a half inches ; very light ; elastic ; of\n* Med. Chirurg. Trans, vol. ix. p. 14.\nt Med. and Phys. Joum. vol. lvii.\n% Schmidt\u2019s Jahrb\u00fcch, B. v. S. 379.\nvox.. IV.\nbrownish grey colour internally, whitish externally, and coated with a white earthy crust.\nFig. 85.\nSection of fibrinous calculus.\nA new substance has recently been added to the list of constituents of urinary calculi by Heller*, under the title of urostealith. This substance is said to form a soap with alkalies, and to have been discharged in small masses varying in size from that of a hemp seed to that of a small nut.\nEach particular division of the urinary passages is the seat-occasionally of calculous formations, and the characters of these are in each site more or less peculiar. Into the description of these characters w e cannot here enter seriatim ; of the varieties thus depending upon the seat of the product \u2014 namely, renal, ureteral, vesical, prostatic, urethral, and pr\u0153putial, \u2014 the most important, the vesical, may be considered to have been specially kept in view in the preceding pages. As respects renal calculi we must content ourselves with illustrating by a figure (fig. 86) the curious branched form\nFig. 86.\nthey sometimes assume, as they gradually mould themselves to the interior of the pelvis and infundibula.\nRenal calculi sometimes attain great bulk. Among numerous examples of the fact we may refer to a case seen by Wilsonf, in which the kidney, perfectly atrophous, and replaced by a multilocular membranous sac (the dilated pelvis and infundibula) contained an oxalate of lime calculus weighing seven ounces and a half. Renal calculi derive much of their practical interest from their tendency to produce such atrophy of the kidney, with pyelitis (U. C. Mus.) or, more rarely, hydronephrosis.\n* In seinem Archiv, Bd. ii. f Lectures, p. 122. ,\nG","page":81},{"file":"p0082.txt","language":"en","ocr_en":"82\tPRODUCTS, ADVENTITIOUS.\nCalculi of the prostate gland are (sometimes at least) essentially different in nature from urinary calculi, and belong to the class produced by morbid secretions from mucous surfaces. Sometimes single, they are more generally numerous ; in the latter case, though occasionally found of much greater bulk, they rarely exceed a pea or small nut in size. One variety of prostatal calculus is, according to Dr. Prout, found in the natural cavities of the gland, before this becomes much disorganized ; the calculous masses referable to this variety are of more or less rounded shape and yellowish-brown colour. Another variety seems to be generally found in an enlarged cavity or abscess of the prostate gland, and sometimes has a highly polished porcellanous appearance. But that this distinction is rather an artificial than a natural one appears from the similarity of composition of both varieties. As first shown by Wollaston, these calculi consist mainly of phosphate of lime and animal matter with carbonate of lime in variable proportions.\nPrceputial calculi and those found in urinary fistulce belong, in the great majority of cases, to the class of saline masses generated through irritation of mucous (or pseudo-mucous) surfaces, and accordingly consist wholty of earthy phosphates. There is no reason, however, that a particle of gravel, or a minute calculus of various chemical constitutions, might not make its way into these situations, and become the nucleus of further deposit : and in point of fact R\u00f6mer found uric acid, phosphate of lime, and animal matter in some calculi removed from underneath the prepuce of a child affected with natural phymosis.\n(\u00f4). Lachrymal calculi. \u2014 Calculous formations in the lachrymal organs, positively speaking rare, are much less commonly met with in the gland and its excretory ducts than in the folds of the conjunctiva, in connection with the caruncula or in the lachrymal canals and nasal duct. They maybe known by the generic name dacryolith, (from \u00eaaicpvov, a tear, and Xido\u00e7, a stone,) first proposed by Walther.\nAn example of the actual formation of such calculous masses in the excretory ducts of the gland occurred in the case of a female, aged 19, who came under the notice of Mr. R. H.Meade, (Med. Gazette, 1835.) Twenty-three calculi, of small size, (the largest about a line in diameter,) rough, very hard, and of dirty white colour, were discharged from the ducts in the course of four or five days. They consisted principally of phosphate of lime, with a small quantity of carbonate of the same base and traces of animal matter. Von Walther describes a curious case, in which calcareous matter continued to be formed in the folds of the conjunctiva during a space of about ten weeks. The first mass formed was of angular shape, about the size of a pea, and easily capable of being rubbed down into a greasy powder. It reappeared in three days ; and subsequently a similar matter formed in the other eye. The deposition ceased under the use of potash internally, but returned three years after; carbonate of lime chiefly, with phosphate of\nlime and animal matter, were its constituents. Numerous examples are on record of such concretions occurring in the follicles of the caruncula. Sandifort, Blegny, Schmucker, Mr. Travers, and others have seen calcareous matter in the lachrymal canals. Krimer* has described a calculus of the size of a small pea, of ash-grey colour, polished, of calcareous appearance, removed from the nasal duct of a woman, who for nine months had laboured under disease of the lachrymal passages.\nThere is a species of calculus, essentially of fatty nature, commonly known as \u201c deer\u2019s tears,\u201d which forms in the fossa just below the anterior canthus of the adult red deer (cervus elephas). It yields on analysis resin with ethereal oil, fatty oil, wax, cellular substance, colouring matter, chloride of sodium, and phosphate of lime. Some of these ingredients are supposed to be derived from hair, which is usually entangled with it. It is said to possess the medicinal virtues of the foetid antispas-modics.f\n(c). Nasal calculi. \u2014 Calculous masses are not extremely uncommon in the nares. Some of them are indubitably formed in the lachrymal passages, whence they glide into the nostrils; such was, in all probability, the case with the little girl spoken of by Bartholinus, who forced small calculi from her nose. In other instances they manifestly originate in the nostrils themselves; this is especially certain when the nucleus of the mass consists of a foreign body. Thus Horn found a calculus in the nares, the nucleus of which was a cherry-stone. Grandoni removed from the left nostril of a woman, aged 32, a calculus formed of fragments of unequal sizes, weighing 76 grains, of a specific gravity of 1.4, without smell, and chemically constituted as follows : \u2014\nPhosphate of lime............... 55.0\nCarbonate of ditto ............. 18.0\nCarbonate of magnesia ........... 7.0\nOrganic matter with traces of iron 20.0\n100.0\nIn the largest of the fragments a grass seed was discovered. J\n(d) Frontal sinus, calculi of\u2014Several calculi of small size, consisting of phosphate of lime, carbonates of lime and magnesia, oxide of iron and soda in small quantity, and animal matter, were discharged from the frontal sinus of a woman, whose case will be found in a foreign journal. \u00a7\n(<?.) Mouth, calculi of.\u2014 The interior of the mouth may become the seat of calculous formation. Schenk, Echold, and Bartholinus relate cases of its occurrence in connection with the mucous membrane of the palate ; Kruger describes a mass of ashen colour, hard, round,\n* Gr\u00e6fe and Walther\u2019s Journal, Bd. x. S. 597. 1827.\nf L\u00f6wendardt, Brit, and For. Med. Rev. vol. xi p. 233.\nJ Brit, and For. Med. Rev. vol. xi. p. 238.\n\u00a7 Gaz. M\u00e9d. de Paris, t. 1. No. 2.","page":82},{"file":"p0083.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n83\nand very light, thrown off from an ulcer in the palate. Otto * knew a person in whom, during an atonic attack of gout, the whole mouth, throat, and gullet were largely covered with a whitish mucus [diphtheritic deposit ?], which contained a large quantity of phosphate of lime.\n(f.) Salivary calculi.\u2014The calculous accumulations met with not very unfrequently in connection with the salivary glands, are commonly regarded as depositions from the saliva, and may be generically termed ptyaliths (iTTva\\ov, saliva, and Mdo\u00e7, a stone). But they are at the least depositions from saliva of morbid composition, for while they are essentially formed of phosphate of limef, this salt scarcely exists in the healthy fluid, and indeed is not enumerated among its ingredients at all by either Berzelius, Graham, or Wright. It becomes, therefore, extremely probable that the excess of phosphate is generated through the influence of irritation of mucous membrane. Salivary calculi are of much more common occurrence in some of the lower animals (e. g. the horse, ass, and dog) than in the human subject.\nThe parotid gland is less frequently the seat of these products than the submaxillary and especially than the sublingual gland. P\u00f6lker extracted an encysted stalactiform calculus, 15 lines long, 9 broad,* and weighing 120 grains, from the parotid, composed of phosphate of lime and animal matter. Breschet describes white calculi of scaly fracture, some of them crystallized in regular tetrahedra, and having a nucleus composed of a grain of oats, which were discovered in the maxillary glands of an elephant : here, in addition to phosphate ot lime and animal matter, there was carbonate of lime. The affection called ranula is produced by obstruction of the ducts of the sublingual gland with calculous matter, which may form a single large mass, or be united into numerous minute ones. Chronic inflammation and abscess are the frequent results of such accumulations.\nOf similar origin is the calculous matter which gathers round the teeth, commonly called tartar or odontoliths (oSav, a tooth, and \\iOo\u00e7, a stone). Two kinds of tartar have been distinguished by DuvalJ : a, tartar of deep grey or even blackish colour, hard and compact, smooth on the surface, breaking almost like glass, and forming first on the root of the tooth, whence it spreads to the enamel ; b, tartar of yellowish colour, less compact, friable, less smooth on the surface, forming on the enamel near the gums, whence it spreads to the crown in the majority of cases, but sometimes insinuates itself underthegums. Tartar appears first as a thin layer of slimy matter, which hardens ; another layer is then deposited, hardens in its turn, and so on. It accumulates enormously in some instances, exceeds the tooth (to which it is often most firmly united)\n* Patholog. Anat. by South, p. 103.\n+ Poggiale (Journ. de Pharmacie, p. 337, 1839) \u2019ound so much as 94 per 100 of this salt j Bull, de la Facult\u00e9 de Med. 1815, No. 7.\nin size, and sometimes detrudes this from its socket. Berzelius found it composed of\nEarthy phosphates ............. 79.0\nUndecomposed mucus............. 12.5\nPeculiar salivary matter (Ptyalin) 1.0 Animal matter soluble in hydrochloric acid................. 7.5\n100.0\nBuhlmann * has recently drawn attention to certain microscopical corpuscles, most frequently met with on teeth surrounded with tartar, yet not altogether absent from the cleanest. Originally described by Leeuwen-hoeck, these bodies are of filiform shape, and found in three conditions : a, yellowish fibres usually collected into tufts ; b, the same fibres broken and scattered among the epithelium and mucus ; c, tufts of fibres mixed up with granular matter. They measure about 0.00006th of a Paris inch in breadth ; from -J^th to i a line in length : they are smooth, arched, or wavy, somewhat elastic and transparent and of yellowish white colour. The strongest nitric, sulphuric, and hydrochloric acids and caustic alkalies produce no change but that of rendering them a little more transparent : they are unaltered by heat. They are chiefly abundant at the junction of the tooth and gum. Infusoria (genera Vibrio and Monas) are also found in this substance.\n(g.) The tonsils are not unfrequently the seat of phosphatic deposit. A calculus formed in one of the tonsils, of greyish white colour, containing an oval nucleus, was found by Wurzer to consist of phosphate of lime 63.8, carbonate of lime 16.7, animal matter 13.3, ptyalin with chlorides of sodium and potassium 7.1, iron and traces of manganese 0.1.f\n(A.) The pharynx and oesophagus have both been, though in extremely rare instances, the seat of calculous incrustations. Rivi\u00e8re and Bartholinus relate such cases.\n(i.) Gastrointestinal calculi. \u2014 The calculi discovered in theintestinalcanalagree, as regards such saline materials as enter into their composition, in being essentially formed of earthy phosphates, especially that of lime. They may, however, be wholly free from saline matter.\nIntestinal calculi are generally few in number, unless when of biliary origin : as many as thirty, however, were found in the stomach by Bilguer. Their size varies remarkably, from that of a nut to a mass larger than the clenched hand : their weight varies proportionally,\u2014they have been known to weigh a pound and a half, two, and even four pounds. Their specific gravity is low, varying from 1000 to 1400. Their shape is irregularly rounded, the irregularity being greatest in the largest masses, and, like biliary calculi, they affect their own forms mutually by lateral pressure. They occur in all parts of the intestinal tract, but are most\n* Muller\u2019s Archiv., H. iv. S. 442, 1840.\nf See also Sch\u00fctz, Caspar\u2019s Wochenscrift, No. 4o, 1838.\nG 2","page":83},{"file":"p0084.txt","language":"en","ocr_en":"84\tPRODUCTS, ADVENTITIOUS.\ncommon in the c\u00e6cum, large intestines, and stomach, and in rare instances have been discharged by the mouth.\nThere is a very obvious distinction between intestinal calculi, seized by almost all writers on the subject, in regard of their origin : (1.) some originate elsewhere, and make their way into the alimentary canal ; (2.) others are the result of the deposition within the intestines of certain materials around some substance acting as a nucleus, itself either introduced from without or from some other part of the system; (3.) others are wholly formed in the alimentary canal.\n(I.) a. Biliary calculi, to be presently described, form the great majority of those belonging to the first class. They present precisely the same characters as while still in connection with the biliary system, b. Calculi sometimes pass into the intestine from the urinary passages. Dr. Marcet found a calculus, mainly composed of a mixture of phosphate of lime and triple phosphate, in the rectum of an infant with imperforate anus. A communication existed between the bladder and rectum.\n(2.) Calculi belonging to the second class vary much in respect of their nucleus ; the matter found in the intestine, constituting the cortex of the calculus, is generally composed of phosphates, applied in layers or not, and mixed or not with additions of the vegetable or other substance which served originally as the nucleus ; the mass is solid and compact, or softer and more porous, and mixed with the mucous secretion of the bowel. The division into layers is sometimes very indistinctly marked ; generally a slight difference of colour exists in the different strata. Yellowish brown is the most common hue.\nThe nucleus in this class of calculi may be animal, vegetable, or inorganic.\n(a.) Animal. \u2014 Under the name of egagro-piles, or hair-balls, have been described masses of not uncommon occurrence in the intestines of the lower animals (especially of calves), composed of hairs in their central part, in their outer parts of concrete animal and saline matter. The hairs forming the nucleus are swallowed by the animals when licking themselves. Laugier* has very carefully described a felly-looking mass of some size found in the human rectum, the cortex of which consisted of f\u00e6ces, hydrochlorate of ammonia and lime, phosphate of lime, silica, and oxide of iron ; the nucleus, prismatic in shape and covered immediately with a brown crust, consisted in its central part of gelatin, in its more external of blood. Probably, as has been suggested, the mass originated, in consequence of a vessel being wounded by a piece of bone, \u2014 blood being effused round this, and saline matters subsequently accumulated round both.\n(b.) Vegetable. \u2014 Nuclei of vegetable matter are more common. In graminivorous animals intestinal calculi of this kind sometimes acquire vast size. In a horse (aged 17 years) a mass\n* Mem. de l\u2019Acad. Roy. de Med. t. i.\nwas found having a nucleus of oat-grains, and so huge as to measure 28 inches round, and weigh 19 pounds (Breschet). Laugier and Lassaigne, in a similar mass, collected round bits of straw, found the cortex composed of earthy phosphates. In the duodenum of the human subject Andral discovered a calculus of the size of a small egg, consisting of earthy-looking matter externally, and having a plum-stone for its nucleus.\nBut the most interesting calculus of this species is endemic in Scotland, and for its full history we are chiefly indebted to the investigations of Wollaston and Dr. Monro Tertius.* The vegetable substance acting as the nuclear basis of the mass (which looks like felt or coarse sand) is the husk of the oat-seed in fragments, along with the minute fibrils, forming a velvety mass at one end of the seed underneath the husk. The abundant use of oatmeal in North Britain, as an article of food, explains the frequent occurrence of these calculi among the population ; they are said by Dr. Maclagan-f- to be growing less common, in consequence of the greater care now bestowed in the north in separating the husky matters in preparing grain for the market. The inorganic constituent associated with the vegetable fibrous matter is mainly phosphate of lime (20 per cent, in two specimens analyzed by Dr. Maclagan), associated with silica, evidently derived from the oat (6 and 4 per cent.).\n(c.) Inorganic. Certain medicines, magnesia (Monro) and chalk especially, have occasionally collected into calculous masses in the large intestine of persons in the habit of swallowing large doses of either for a considerable time : the saline matter being hardened into a solid ball with mucus and f\u00e6cal matter. Croc-keltj relates the case of a child who swallowed a pin, and at the age of 18 voided per anum a calculus of spheroidal shape and earthy composition. The head and half the stem of the pin were enclosed in the mass. A piece of wood accidentally forced into the rectum has been known to form the nucleus for phos-phatic deposition.\u00a7 Females who chew and swallow the ends of threads used in sewing, or indulge in the singular habit of eating their curling-papers (hysterical pica), occasionally become the subjects of intestinal calculi.\n(3.) Calculi formed wholly in the digestive passages are comparatively rare. They may consist of faeces and inspissated secretions wholly (under which circumstances the name, calculus, is not in strictness applicable to them), or these may serve as a nucleus for the deposition of the ordinary phosphatic salts. White discovered, near the ilio-coecal valve of a tuberculous subject, two masses (one weighing two, the other one and a-half pounds) com-\n* Morbid Anatomy of the Human Gullet, &c. 1811.\nt Lond. and Edinb. Month. Journ. of Med. Science. Sept. 1841.\nt North American Journal, 1827.\n\u00a7 Dahlankamp, Archives Gen. de M\u00e9d. t. xxiii.","page":84},{"file":"p0085.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n85\nposed of a nucleus of indurated faeces, and a cortex of saline matter arranged in layers. Oleaginous matters sometimes accumulate in the intestine in the form and of the consistence almost of calculi. A mass of this kind, voided by a young tuberculous female, and examined by M. Lassaigne, was found to consist of\nAcid fatty matter J \"\t1 n\ncomposed of \\ Peculiar acid J\nSubstance analogous to fibrin ... 21\nPhosphate of lime................. 4\nChloride of sodium................ 1\n100\nThese oleaginous formations will be presently further considered.\nThe oriental bezoard, a resinous intestinal calculus, chiefly met with in certain species of goats and deer, appears (like ambergris in the whale) to be the result of morbid secretion from the bowels of the animal, and not to be composed (as was imagined by Vauquelin) of materials derived from its food. A very doubtful case of calculus occurring in the human intestine, with close resemblance to ambergris in its characters, has been published by Dr. Kennedy.*\nWe have lately examined some masses composed solely of fibrin, (Univ. Coll. Mus. presented by Dr. Rayner,) passed from the rectum after prolonged sufferings, simulating those of cancerous disease.\n(/c.) Biliary. (Gall stones, Choleliths).\u2014 Biliary calculi are found in every part of the system where the bile circulates, and even make their way occasionally into localities in which that fluid is not naturally found. Most common in the gall-bladder, they are frequent in the larger ducts ; far less rare than has been affirmed by some writers in the radicles of the hepatic duct, not uncommonly encountered in their transit through the different parts of the intestine (where it is possible they may be sometimes actually formed), they are very rarely seen in the stomach.\nBiliary calculi vary in number from one to several hundreds and even thousands : 3,646 are said to have been shown by Fuschius from the gall-bladder of a certain gladiariusf ; and Dr. Parry J gives a case in which 2,654 were found in the same part. It is not uncommon to find one only, or two, three, or four ; but observations are wanting as to the relative frequency of small and large collections. Their size varies as their numbers. When single or few in number, they are comparatively large, have been known to reach the bulk of a hen\u2019s egg \u00a7, but rarely, even when single, exceed a walnut in dimensions ; when very numerous, they are sometimes scarcely larger than pins\u2019 heads, and some, of these small dimensions,\nmay be associated with others of far greater bulk.\nTheir form likewise varies to a certain extent with their number. When single, the spherical, oval, or elongated shape predominates ; when numerous, they press upon and mould each other into cubic, pentagonal, or polygonal figures, with obtuse and rounded angles.\nTheir most common colour is greenish yellow ; but various shades of brown, green, dark or canary yellow, and even black or white, are observed. Their colour frequently varies in different parts of the mass ; and the differences of hue may either correspond to the lamellae of the calculus, or to the matters acting as the nucleus and the cortex respectively (the most common case), or be irregularly observable over the surface so as to produce a mottled appearance. Biliary calculi have a smooth surface and slightly unctuous feel.\nWhen a biliary calculus is broken across, a distinction of nucleus and cortex is very commonly seen. Complete homogeneousness, without any lamellar or other obvious arrangement, is extremely rare. The cortical portion generally consists of dull-looking lamellae arranged concentrically, but also striated tians-versely. A tendency to the alternating character of urinary calculi is sometimes visible : thus in the central point may appear a dark coloured and homogeneous matter in Fig. 87. small quantity (bile pigment), and from this shining strata (cholosterin) radiate towards a cortex such as that above described {fig. 87.) The thickness of the cortex varies in different parts; though Fractured surface generally greatest at the of a biliary cal- angles of polygonal calculi cuius.\t{fig. 87), this is not always\nthe case. In a few instances on record a foreign body {e.g. a piece of needle) has been found forming the nucleus of a biliary calculus; such cases are of singular rarity, however, and for obvious reasons.\nThe constituents of biliary calculi are cho-lesterin (the chief one) with other kinds of fat in small proportion, choleate of soda, bilifel-linic acid or biliary resin mixed with bile pigment, epithelium, and mucus. In some cases the mass is almost wholly composed of colouring matter * * * \u00a7 ; in others of biliary resin and modified colouring matter, with mere traces of cholesterin.f Berzelius describes a gall-stone composed principally of carbon. Von Bibra % discovered 1.5 per cent, of alumina with iron, and 1.4 per cent, of carbonate of lime in a biliary calculus ; the latter salt was also detected by Witting in considerable amount. A calculus analyzed by Bally and Henry J consisted of carbonate of lime with traces of carbonate of magnesia 72.70, phosphate of lime 13.51, mucus with a little peroxide of iron and\n* London Med. Chir. Journal, vol. iv.\nf Morgagni de Sed. &c. Ep. 37, \u00a7 19.\nj On Angina Pectoris, p. 240.\n\u00a7 Saye, Journ. des Savans, Sept. 1697. Baillie, Morbid. Anat.\n*\tArchiv, der Pharmacie, Bd. xli. S. 291. f Simon, loc. cit. p. 470.\nt Eod. loc.\n*\tG 3","page":85},{"file":"p0086.txt","language":"en","ocr_en":"86\nbile-pigment 10.81. Bertazzi* * * \u00a7 maintains copper to be a constant ingredient of biliary calculi, having found it in every one of fourteen specimens, apparently to an amount varying directly as the quantity of colouring matter present. Heller f confirms the statement of this chemist. Bertazzi failed in detecting copper in the bile collected from the gall-bladders of ten persons. In very rare instances calculi have been found composed of inspissated bile.\nMr. Taylor J discovered a calculus in the collection of the College of Surgeons, presumed to be biliary, and composed of the stearate of lime. It floated in water, and had a lamellar structure ; the lamellae being easily separable and alternately of white and reddish yellow colour. In the centre was a small cavity. The analysis, justifying the above view of its composition, is given in full. This rare description of calculus appears to signify a stage of transition from the common cases to those instances in which the biliary passages contain masses composed essentially of carbonate and phosphate of lime, especially of the former salt. Richter describes a case in which the liver contained a multitude of such bodies varying in size from a pea to a cherry. Matter of this kind is occasionally found coating the gall-bladder and ducts ; and in the interior of cysts in the substance of the organ. (Baillie and Zannini.)\n(1.) Pancreatic. \u2014 Calculi of the pancreatic duct have been observed in rare instances by Matani, Eller, Biumi, Galeati, and others. Baillie found some as large as a hazel-nut, of white colour and irregular surface, which Wollaston $ showed were composed of carbonate of lime.\nFig. 88. represents a portion of a dilated pancreatic duct, which contained an enormous number of small calculi (such as are seen within it in the sketch) of dull white colour, perfectly round, varying in size from that of a pin\u2019s head to that of a small pea, elastic and hard.\nFia. 88,\nPRODUCTS, ADVENTITIOUS.\nPancreatic calculi, natural size. ( Univ. Coll. Mus.\nPancreatic calculi have not, as far as we are aware, been found in the intestine in transitu outwards.\n(m.) Seminal. \u2014 Calculous masses have occasionally been detected in the vesicul\u00e6 s\u00e9minales and ejaculatory ducts. || Collard de Martigny found some composed of mucus and coagulated albumen chiefly, with a small quan-\n* Polli, Annali di Chemica ; Milano, Juglio, 1845\nf Archiv, vol. ii. p. 228.\n% Lond. and Edinb. Phil. Mag. 1840.\n\u00a7 Pemberton, Diss. of the Abdom. Viscera, p. 68.\n|| Hartmann, De calc, in vesic. seminal. Erfurt, 1765.\ntity of calcareous salts.* These calculi sometimes accumulate in vast numbers ; thus two hundred were discovered in the right vesicula seminalis of a man aged forty-five-f; no symptom had occurred during life connected with the organ.\n(n.) Mammary. \u2014 The lactiferous ducts are occasionally the seat of minute calculous bodies ; Gooch, Haller, Reil, and others report cases of the kind. Morgagni alludes to their existence in the breast of a gouty person. The history of the case generally connects their production with the function of suckling, and sometimes with obstruction of the flow of milk.\n(o.) Vaginal and \u2022pudendal.\u2014Calcareous accumulations in these parts are not extremely rare. They originate in a deposition of phosphates around some foreign body; a pessary for example, or around a nucleus of thickened mucus accumulating either from habits of uncleanliness or from malposition of the uterus. K\u00f6hler discovered five large chalky-looking masses, weighing together more than seven ounces, in the vagina of a woman, aged forty, affected with prolapsus uteri.\n(p.) Uterine.\u2014The internal surface of the uterus is in rare instances found more or less extensively lined with, or studded with rounded masses of, saline matter of variable consistence. This condition has been observed in cases of deviation. of axis of the uterus ; the saline matter is in all probability composed mainly of phosphate and carbonate of lime.\n(B.) Concretions or Pseudo-calculi.\u2014 Concretions are masses composed of saline materials deposited in a pre-existing organic basis,\u2014 the former, as they increase, gradually encroach on and, as it were, dispossess the latter, until eventually, in many instances, all obvious traces of its existence have disappeared. The saline matters are commonly deposited punctatim ; and the organic basis, in which they accumulate may be non-stromal (as, for example, tuberculous matter, atheromatous matter, &c.), or stromal (as, for example, fibrous tumour, &c.) And, again, the natural \u2014 textures (as, for instance, cellular tissue, H# tendon, &c. in the case of tophaceous con-Tf cretions) ; the solid elements of the cir-_ culating fluid (as the fibrin of the blood in the case of phleboliths) ; and, lastly, various adventitious'substances (as those mentioned above), may severally act the part of that organic basis.\n(a.) Elementary cell. \u2014 Perhaps the simplest form of true concretion is that in which an epithelium-cell becomes coated or studded with saline material. We have seen this condition in the epithelium lining adventitious cysts, in the epithelium floating in pleuritic effusions, and occasionally in that discharged with the urine. The concretions, not very uncommonly found in the choroid plexus, consist of round cells coated with calcareous salts. Flakes of albuminous substance may some-\n* Journ. de Chim. Med. t. iii. p. 133. f Archives de M\u00e9decine, Juin, 1831.","page":86},{"file":"p0087.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\ntimes be seen in the urine coated with saline matters ; but this is merely a rudely analogous condition to those previously mentioned.\n(6.) F\u0153tal (petrifactions).\u2014At the opposite extreme to cases in which a simple elementary cell becomes the depositary of calcareous matter, stand those remarkable instances in which an entire individual becomes more or less completely invested with a coating of such matter ; while subsequent desiccation of the tissues (with, very rarely, partial calcification of these) mummifies the entire frame.\n(c.) Placental.\u2014Calcareous concretions are of not uncommon occurrence in the human placenta. Hannover found them in large number in twenty of two hundred placentae. They are of white colour, rounded or branched in shape, and composed of phosphate of lime ; generally seated on the uterine, rarely on the foetal, surface, near the border. The age and constitution of the mother or of the child, separation of the placenta, and haemorrhages, appear to Hannover to be without influence on their production.\n(d.) Vascular.\u2014Arteries,\u2014(1.) Parietal.\u2014 There are few conditions more familiar to the observer than the calcareous deposition in the coats of arteries, long erroneously styled \u201c ossification \u201d of these tubes. The saline materials, giving the ossiform aspect to the deposition, assume four different forms: 1. That of a gritty looking substance sprinkled over the internal surface of the vessel ; 2. That of patches of variable size and thickness, sometimes sufficiently extensive to convert a considerable tract of the vessel into an inflexible tube ; 3. that of small rounded or shapeless masses, protruding or not into the interior of the vessel ; 4. that of prominent spicul\u00e6 ; when their anatomical constitution appears more allied than under other circumstances to that of bone.\nMr. Brande found these incrustations to consist of sixty-five and a half per cent, of phosphate of lime and the rest of animal matter. These proportions must of course vary in different cases : thus Scherer * found \u201c ossified \u201d arterial membrane composed of \u2014\nOrganic matter........... 7.292\nPhosphate of lime...... 63.636\n---------- of\tmagnesia.. 10.909\nCarbonate of lime...... 18.181\nM. Bizot f has given a tabular view of the relative frequency with which different parts of the aorta become the seat of this condition ; and from this we learn with more precision than could be otherwise attained, that the points at which the different branches are given off are far the most frequently implicated ; and that the posterior surface of the thoracic and abdominal divisions of the vessel suffers more frequently than the anterior in the proportion of 11 to 1.\nThe precise seat of calcareous deposit, in respect of the coats of the tubes, has been\n* Simon, loc. cit. p. 477.\n\\ Mem. de la Soci\u00e9t\u00e9 M\u00e9d. d\u2019Observation, t. i.\n-87\nmade matter of much disputation. We have ourselves found that in the aorta the new matter is thrown out between the middle and internal coats, and in the vessels of the limbs either in this situation or in the actual substance of the middle coat ; \u2014 or, to use the language which the modern anatomy of arteries would require us to adopt, we should say that the saline matter is deposited in the aorta in the striated and longitudinal-fibrous tunics between the epithelial and circular-fibrous tunics ; and also, in the arteries of the limbs, in the substance of the circular-fibrous and true elastic coats.\nThere are three kinds of deposit, of common occurrence in the arteries, set down by writers as the nidus in wrhich saline accumulation may occur: these are the\u201c atheromatous matter,\u201d the \u201c white spot,\u201d and the \u201c cartilaginous patch.\u201d The origin and nature of these matters require to be briefly examined.\nThe atheroma of the arteries and cardiac valves is a yellowish matter occurring in minutel particles, hardly larger than grains of sand ; separate or clustered into small patches ; most abundant at the points where vessels are given off\u2019 from the affected trunk ; obviously seated underneath a coating of epithelium, and even probably under the striated tunic of the artery, (as when an attempt is made to peel it away by raising these two coats, it is in part removed with them, and remains partially adherent to the deeper-seated tunics) ; and distinctly unctuous to the feel, when accumulated in any quantity. The substance is indeed of fatty nature. Gluge* found that \u201c an enormous deposition of fat globules solely and alone constitutes this morbid state, and in fact even with the naked eye a remarkable similarity may be perceived between the atheromatous state and certain forms of fatty deposition in the liver.\u201d Mr. Gulliver f has independently ascertained the same fact, and illustrated his description by figures. J\nThe researches of M. Bizot have very clearly established that this atheromatous matter becomes, with the progress of things, the seat of one or other of two series of changes, terminating in the one instance in ulcerous softening, in the other in calcareous deposition. The stages of the ulcerous softening are four : in the first the yellow matter becomes slightly prominent on the surface of the vessel, and the superficial fibres of the \u201c middle \u201d tunic lose their natural consistence ; in the second the internal membrane is raised into little eminences by the accumulation of a matter which is sometimes liquid and puriform-looking, sometimes floury and dry, and occasionally containing minute shining scales, some of\n* Anat. Micros. Untersuchungen, Erstes Heft, S. 130, 1838.\nf Med. Chir. Transactions, vol. xxvi. p. 86, 1843.\nJ We have occasionally found plates of Cholesterin in greater abundance than oil-globules, \u2014 a fact having an obvious connection with the established circumstance of the excess of cholesterin in the blood of old persons.\nG 4","page":87},{"file":"p0088.txt","language":"en","ocr_en":"88\nPRODUCTS, ADVENTITIOUS.\nwhich have a white and silvery look (choles-terin). In the third stage depressions with a smooth surface, (except in the points where the lining tunic has undergone fissure for the evacuation of the matter described,) mark the previous seats of this matter. The fourth stage is distinguished by the disappearance of the lining membrane in the affected points, and hence by actual excavation. Neither suppuration nor injection attend the changes reviewed.\nWhen the atheromatous matter undergoes the calcareous change, a hard but minute point commonly appears in its centre; this gradually increases, especially in breadth, the middle coat being earlier implicated than the lining tunic, which is occasionally covered with concrete fibrin. Eventually the lining coat is destroyed, and the concretion brought into contact with the blood ; the middle coat rarely becomes affected through its entire thickness. The deposition may commence in a multitude of minute points simultaneously, whence the atheromatous matter acquires a gritty feel.\nThe white and cartilaginiform patches are not in any instance the nidus of the saline deposit, according to M. Bizot ; at least he has never succeeded in tracing the early processes of deposition in those patches. Nothing, however, he admits is more frequent than the deposition of atheromatous and subsequently of calcareous matter underneath the \u201c cartilaginous \u201d patch, which is occasionally perforated by the calcareous substance, and an appearance produced easily explaining the current opinion that the patch in question is the original seat of the saline particles. We agree with M. Bizot that the \u201c cartilaginous\u201d patch is altered plastic matter exuded on the inner surface of the vessels. Mr. Gulliver has, it is true, discovered fat-globules and crystals of cholesterin in the \u201c white patch \u201d of vessels ; but the circumstance appears explicable in the manner just referred to as resulting from the French author\u2019s inquiries.\nIn the arteries of the limbs calcareous depo sition may likewise commence in the middle coat itself, which becomes harder and thinner as the disease advances.\nIt is important to observe that the close examination of calcareous plates through their various phases of development demonstrates, as we have seen, their independence of inflammation.\nCalcareous deposition is remarkably dependent upon age. Bichat calculated that the arteries of seven of every ten persons beyond the age of sixty were thus affected ; while its existence is extremely rare in early youth. Writers have indeed maintained the perfect immunity of the vessels of youthful subjects from this change : but Mr. Young found the temporal artery of a child fifteen months old converted into a calcareous cylinder ; Otto * once discovered incipient ossification of the aorta in a girl of seventeen; Wilson met with a similar condition in a child three years old; Andral in a girl aged eight; and numerous\n* Patholog. Anat., by South, p. 333.\nother instances of the kind are recorded. Calcareous deposition is more common in vessels of a large than of a small calibre, and especially in the aorta; rarer in the upper than the lower extremities ; it sometimes extends through the entire arterial system of the trunk and lower limbs, \u2014 we have before us the vessels of a subject in this condition, who died with gangrcena senilis. * Such disease never occurs, according to Otto, in the arteries of the thoracic and abdominal walls, and perhaps those of the alimentary canal and liver ; and is, on the contrary, common in those of the pelvis, of the brain, of the thyroid gland, the heart, the spleen, the kidneys, &c. The pulmonary artery is, comparatively speaking, considered exempt from calcareous deposition ; several instances, however, are referred to by Otto, in which it was more or less completely \u201cossified;\u201d it is not unfrequently so where the right and left cavities of the heart communicate, (but here the vessel is placed in respect of its contained fluid in the state of an ordinary artery). Hope f attended a lady, aged 60, in whom the \u201c pulmonary artery was found quite ossified where it plunged into the lungs ;\u201d and from our own records of cases we know that slight alteration is not very uncommon.\nThe close comparison of corresponding vessels on the two sides of the body has led M. Bizot to the discovery that not only the same vessels, but the same parts of these, are, with the rarest exceptions, affected with the same alterations of structure,\u2014that a law of symmetry regulates the development of these. Upon this point much curious information will be found in M. Bizot\u2019s admirable essa}\\\nCalcareous deposition is common in the arteries of syphilitic subjects, and of those who have taken mercury to excess. Much fanciful hypothesis has been indulged in respecting the influence of certain kinds of diet on its production.\nThis morbid state destroys the elasticity of the arteries, renders them fragile, and interferes with the circulation ; we have known it lead to rupture of the aortic valves. The calcareous matter protruding more or less into the vessel affords a centre for the blood to coagulate around, and may lead to its complete obliteration,\u2014a result which it would appear may be produced by mere thickening of the coats ; in either case suspension of the circulation and gangrene are the results. \u201c Ossification \u201d of the coronary arteries of the heart has been met with in cases of angina pectoris (recently by ourselves) and of sudden death, \u2014 probably rather acting as the occasion, than the cause, of both.\n(2.) Central. (Arteroliths.) \u2014 Calcareous concretions, free in the interior of the arteries, are as rare as the conditions which we have just described are common. OttoJ saw in the Copenhagen Museum \u201c a round stone as large as a pea,\u201d said to have been taken from the\n* Univ. Coll. Mus.\nf Diseases of the Heart, 3rd ed., p. 589.\nx Path. Anat., by South, p. 335.","page":88},{"file":"p0089.txt","language":"en","ocr_en":"89\nPRODUCTS. ADVENTITIOUS.\nspermatic artery ; but he believes it to have probably been of venous origin. Eight loose stony concretions have, he observes, been met with in an aneurismal sac*; the largest of these was as big as a plum. L\u00e4nderer has recently analyzed an aortic concretion, which contained 14 per 100 of uric acid.j'\nVeins. \u2014 Parietal concretions are as rare in the veins as common in the arteries ; central concretions as frequent in the former as rare in the latter vessels.\n(1.) Parietal.\u2014 These are in truth of extreme rarity in the veins. That they do occur, however, and with somewhat greater frequency than is admitted by speculative writers, is certain. An example of\u201c ossification\u201d of the coronary veins is related in the Ephem. Nat. Cur. Dec. iv. An. x. Obs. 175; Cruveilhier J once found the popliteal veins studded with ossifications similar to those existing in the accompanying arteries ; not a few examples of \u201c ossification\u201d of the vena porta are on record \u00ff ; Morgagni and Baillie found the vena cava inferior in a similar state, &c. In many cases of the kind there appears to have been calcification of the parts immediately adjoining the vessels.\nThe sort of antagonism existing between the arteries and veins, in respect of parietal concretions, has been referred by Bichat to difference of structure of the lining membrane in the two classes of vessel ; by Bizot to the dissimilar properties of the blood circulating in them ; by others, who regard the deposition as evidence of decay, to the greater activity and consequent earlier exhaustion of the arterial tubes. None of these notions are unopen to objection.\n(2.) Central. \u2014 Central concretions in the veins (pheboliths, from <f>Ae\u00ff, a vein, and \\i0os, a stone,) are generally of ovoid or rounded shape ; vary in size from a pin\u2019s head to a pea and upwards, in rare instances attaining the bulk of a hazel-nut, and in weight average about a grain or a little more at most ; are of low specific gravity; occur singly or in numbers varying from two to ten and upwards ; are either perfectly free, or adherent to the internal surface of the vessel either directly or by means of a slender peduncle (these three conditions may be observed in the same vein) ; are smooth on the surface, and (whether partly sanguineous or wholly calcareous) invested with a delicate membrane of serous aspect.\nThese concretions are unquestionably by far more common in the veins of the pelvic viscera (the spermatic, the ovarian, the vesical, the h\u00e6morrhoidal,) than in others. They are not unusual in the splenic veins, and have been met with in the renal, mesenteric, prostatic (thirty were found in the latter by Ehrmann ||), and pubic veins ; they have been seen twice\n* Biermayer, Mus. Anat. Path. p. 101, No. 360.\nf Med. Gazette, July, 1847.\nt Essai sur l\u2019Anat. Path. t. i. p. 70.\n\u00a7 Ruysch, Thes. Anat. viii. No. 58 ; Meckel Path. Anat. Bd. ii. Abth. ii. S. 190.\n|| Compte Rendu des Trav. Anat. &c. p. 38. Strasb. 1827.\nby Cloquet in the vena cava inferior. They occur sometimes in varices of the lower extremities * * \u00a7 ; Dupuytren found them in the anterior and posterior tibial veins ; but they have not, so far as we are aware, been seen in the veins of the arms.\nGmelin f found them composed of\nAnimal matter............. 27.5\nPhosphate of lime......... 53.5\nCarbonate of lime......... 15.5\nMagnesia and loss.........  3.5\n100.0\nThe part of the vein containing a phlebolith is sometimes much dilated, and eventually the vessel may become obliterated above and below the obstruction. Lobstein conjectures that the new formation with its investing portion of vein may be altogether separated from its connections ; and, in the case of the h\u00e6morrhoidal veins, passed by stool.\nHodgson supposed that these bodies were first formed external to the vessel, and subsequently made their way into its interior ; An-dral that their original seat was the substance of the walls of the vein. The occasional existence of a peduncle does not, as has been presumed, really warrant these notions ; as it may no doubt be formed either of fibrin or of plastic matter (thrown out by the tunics from secondary inflammation) coated with epithelium. Besides, the absence of marks of rupture of the surface further confutes them. It was suspected by CruveilhierJ, taught by Lobstein\u00a7, and proved by Carswell ||, that phleboliths originate in clots in the interior of the vessels. The following is the series of changes observed :\u2014stagnation occurs ; a clot forms ; loses its red colour ; becomes concentrically stratiform ; acquires fibrous consistence, and gradually grows calcareous and indurated, stratum by stratum, from the centre outwards, until the whole mass acquires almost stony hardness. Dr. John Reidlf regards the process of induration as one \u201c resembling the formation of osseous tissue in other parts of the body a view invalidated by the absence of true cartilaginous matrix, or of osseous texture at any period of the evolution of the bodies in question.\n(e.) Lymphatic and lacteal.\u2014Although it is possible that the extreme rarity with which the lymphatic and lacteal vessels have been found to contain calcareous matter may in part depend upon those vessels being seldom examined, yet it is certain that such condition is really singularly uncommon. Cheston Browne** refers to a casein which the entire thoracic duct from the receptaculum upwards was \u201cossified\u201d and obliterated. J.D. Scherbff\n* Bouillaud, Rev. M\u00e9d. Avril, 1825. f Tiedemann\u2019s Zeitschrift, Bd. iv. H. i. 1831. t Essai, t. i. p. 71.\n\u00a7 An. Path. t. i. p. 505.\nIl Fascic. Anal. Tissues.\nEd. Med. and Surg. Joum. No.T23.\n** Phil. Trans, vol. lxx. p. 323, 1780. ff De calculo in duc. thorac. 1729 ; Haller\u2019s Diss. Path.","page":89},{"file":"p0090.txt","language":"en","ocr_en":"90\nPRODUCTS. ADVENTITIOUS.\nhas described a concretion found in the thoracic duct. The lymphatics of the small intestines have been found in this condition by Walther.* * * \u00a7\nThe lymphatic glands, especially the bronchial and mesenteric, are, however, not unfre-quently the seat of calcareous precipitation in points, patches, or through their entire substance ; it chiefly occurs in connection with tuberculous disease.\n(/.) Serous and synovial cavities. \u2014 These cavities occasionally contain calcareous productions, evidently produced by the deposition of saline matter in a pre-existing organic basis. This basis, commonly effused fibrin (when the concretion has been free from the moment the process of saline deposition commenced), has in other instances been the substance of fibrous tumours once attached beneath the serous membrane, and accidentally set free.\n(g.) Similar bodies are occasionally found in connection with the fibrous membranes. Andralf describes a very interesting case of tumour of this kind attached to the tentorium cerebelli.\n(A.) Cerebral. \u2014 A concretion taken from the brain analyzed by LassaigneJ was found to be composed almost wholly of fibrin, of a small quantity of cholesterin, and of 4 per cent, of phosphate and carbonate of lime\u2014the evident, though rare, result of previous haemorrhage. A concretion from the cerebellum, examined by Simon \u00ff, about the size of a nut, of irregular angular form, very solid, both internally and externally resembling a piece of bone, and enveloped in a fine coriaceous capsule, consisted principally of phosphate and carbonate of lime with a little cholesterin. A similar concretion analyzed by John consisted of 75 parts of phosphate of lime and magnesia, and 25 of animal matter ; another examined by Morin was composed of cholesterin, coagulated albumen, and earthy phosphates.\n(i.) Uterine. \u2014 Much confusion has arisen from want of accurate distinction of the different kinds of saline deposition occurring in the uterus. These kinds, we hold to be, three in number. 1. The internal mucous surface may be coated with phosphatic salts. 2. The parenchyma of the organ may contain \u201c ossiform \u201d (really calcareous) globular masses resulting from the deposition of saline matter in the interior of fibrous tumours. 3. The uterine tissue may be the seat of phosphatic accumulation around foreign bodies. These bodies may be either introduced (a) from without, or (b) enter the uterus from some other part of the genital system, (a) Of the former case Brugnatelli records a curious instance. A calculus weighing about two ounces, of rough surface, and composed of phosphate of lime, was removed from the uterus of a young peasant, and on division found to have a small\n* M\u00e9m. de l\u2019Acad. des Sciences de Berlin, 1786-87, p. 21.\nf Cl. Med. t. v. p. 8.\nJ .Journal de Chim. Med. t. i. p. 270.\n\u00a7 Loc. cit. p. 474.\npiece of the tibia of a fowl for its nucleus,\u2014 broken off, no doubt, from the entire bone, which had been introduced per vaginam,for the purpose of inducing abortion, (b) Fragments of foetus derived from extra uterine pregnancy, as also moles and hydatids, occasionally form the nucleus or basis of saline concretions.\nThe Fallopian tubes, too, sometimes contain calcareous concretions. Walther had in his possession a globular calculus of yellowish colour, a third of an inch in diameter, weighing ten grains, taken from the left Fallopian tube of a woman aged forty. It is extremely probable, though not proved by examination, that these masses are, in some instances at least, the remains of fibrous tumours.\n(/c.) Pulmonary concretions. \u2014 The pulmonary parenchyma is an extremely frequent seat of concretions. The basis, in which the saline material accumulates, is by far the most frequently tuberculous ; more rarely the fibrinous substance of simple inflammatory exudation forms its nidus : numerous points of interest are connected with these kinds of concretions, and will be more fully referred to in the section on tubercle. Cancerous substance in the lung may become locally infiltrated with saline substances ; we have not known such change to occur in blood effused in this parenchyma.\nThe appendages of the lung are likewise among the habitats of concretions. Fibrinous exudations in the pleura occasionally form the basis for simple saline precipitation ; or less frequently of an ossification-process. The bronchi become in very rare instances more or less completely blocked up with solid concretions, the organic basis of which, in the majority of instances, is not improbably (but this point requires further investigation) that material holding a medium position between diphtheritic deposit and common inflammatory exudation matter, which constitutes the anatomical character of \u201c plastic bronchitis.\u201d Ina case observed by Gorup-Besanez*, such, however, could not have been the origin of the saline accumulation, \u2014 at least presuming the chemical analysis to have been correct. Here a coral-like \u201c ossification \u201d was found in the bronchi of a man aged forty-five, as thick as a crow\u2019s quill, and extending through the whole length and breadth of the lungs. It broke with a crack ; whether it was hollow or not,\nwe are left to conjecture. On analysis it furnished\nFatty matters and traces of soluble\nsalts .......................... 17.17\nMucus ............................ 32.46\nPhosphate and carbonate of lime, with traces of oxide of iron \u2014 50.37 (l.) Arthritic. \u2014 The substances termed\ntophi or gouty concretions belong to the present class. Variable in shape, rounded or tuberculated ; of yellowish white or brownish red colour externally, internally white ; varying in consistence from soft toughness to very considerable hardness; sometimes unctuous to the feel; and apparently enveloped in a\n* Heller\u2019s Archiv. Feb. 1846, or Medical Times, 1846 ; also Tice, in Med. Chir. Trans, vol. xxvi.","page":90},{"file":"p0091.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t91\ndelicate membrane; these productions form within the lamin\u00e6 of the capsules of the joints of the hands and feet, sometimes in the surrounding cellular membrane, and least commonly in the tendons. Their substance has a chalky look on section.\nTheir chemical constitution was first made out by Fourcroy and Wollaston; most correctly by the latter. Urate of soda forms their main saline constituent ; with this is associated urate of potash and lime in small quantity, chloride of sodium in good proportion, and animal matter.\nA gouty calculus from the metacarpus of a man aged only twenty-two, examined by Lehmann, presented innumerable four-sided prisms, arranged in stellar groups, consisting of urate of soda. The composition was as fol-\nlows : \u2014\nUrate of soda............. 52.12\nUrate of lime............... L25\nChloride of sodium ....... 9.84?\nPhosphate of lime.......... 4.32\nCellular tissue .......... 28.49\nWater and loss............. 3.88\nThe abundance of urate of soda in these calculi is a very remarkable feature in their constitution ; and points to the probability of that salt existing in the blood of gouty patients.\n(m.) Cutaneous. \u2014 The natural secretion of the sebaceous glands may be retained within those sacs in consequence of accidental closure of their orifices. And if the saline materials predominate much over the organic, either as a fault of original secretion or from inspissation, a concretion is the result. Epithelium and fatty matters of various kinds are always associated with the saline materials. . These saline materials, which vary much in their per-centage quantity, are mainly phosphate and carbonate of lime.\nSUB-CLASS II. \u2014 ANIMALIZED PRECIPITATES.\nThe distinctive character of products of this sub-class is, that they are exuded ready formed from the vessels ; when (ceasing to mix with, or precipitated from, the blood) they appear as \u201c products \u201d outside the vessels, they possess as much of the attributes of organization as they are ever destined to acquire. The elements composing them are organic ; but these elements are either by nature incapable of forming structure, (as sugar, oils,) or circumstances deprive them of the power they naturally possess of developing a structure (as certain protein-compounds) : they are distinctly non-plastic.\nThe animal substances enumerated, when exuded from the vessels, always form (what may be called) \u2019potentially the material of precipitates ; but circumstances occasionally prevent the actual formation of these. The morbid process essentially consists in exudation (secretive or other) from the bloodvessels \u2014 this is the theoretical precipitation. Tt would be a needless refinement to make a subdivision of actual precipitates and non-precipitated potential precipitates.\n\u00a7 I. Protein-Compounds. \u2014 When oc-\ncurring as actual precipitates, the protein-compounds appear as minute microscopical particles, amorphous or granular ; they absorb readily the ioduretted solution of iodide of potassium, and become of yellowish brown colour; they are insoluble in \u00e6ther, altered but not dissolved by acetic acid, insoluble in mineral acids, and dissolved by maceration in caustic alkalies.\n(A.) Albumen.\u2014Of the so-called protein-compounds albumen is by far the most frequently observed as an adventitious product belonging to the present division. It is either (a) thrown off with certain secretions (of which it forms no part in the natural state ;) or (b) it is retained in a structureless or non-organi-zable condition.\n(a.) Albumen in the secretions. \u2014 Of these the most important is the urine. This fluid, as discharged from the bladder, is found, in a considerable variety of local diseases or general derangements of the system, to be impregnated either temporarily or more or less permanently, either slightly or abundantly, with albumen.* The various conditions under which this impregnation occurs were classed several years ago by us in the following manner ; the advance of knowledge has in the intervening period rendered scarcely any change necessary. M. Martin-Solon\u2019s term Albuminuria may be conveniently used to signify the discharge of albuminous urine generally; but cannot be logically used as a synonym of (nor even as a convertible term for) the affection known as \u201c Bright\u2019s Disease.\u201d\nAlbuminuria may be caused b}' \u2014\nFirst : An unnatural state of the blood. Secondly : Morbid states of the genito-urinary organs, either functional or organic, and when organic, either causing albuminous impregnation during, or subsequently to, the act of secretion. Thirdly: Accidental admixture of genital products. Fourthly : Some cause hitherto unestablished. A few remarks on these various conditions are absolutely called for.\nFirst : Albuminuria from an unnatural state of the blood. Dr. Blackall, in his work on dropsies, has related cases of scorbutus and petechi\u00e6 in which the urine was coagulable ; but as the condition of the kidneys was not inquired into, the narratives are unsatisfactory. M. Rayer-f-, however, states that he has found the albumen and red corpuscles of the blood pass occasionally into the urine in cases of scurvy, purpura, and haemorrhagic fevers ; while the fibrin diminishes in the vessels, and the watery portion becomes infiltrated into the cellular tissue, or exhaled on membranous surfaces. Traces of albumen were discovered by Heller J in the urine of a girl aged nineteen,\n* Some chemists believe that urine naturally contains albumen, though in proportion so small as not to be reached by existing means of analysis ; among these chemists rank Henry, Chevalier, and Dumas, (Le\u00e7on sur la Chimie Statique des \u00eatres organised, p. 39.)\nf Maladies des Reins, t. i.\n\\ Archiv, f\u00fcr Chemie, Bd. i. S. 12.","page":91},{"file":"p0092.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n92\nindependently of red corpuscles, in a case of purpura. In the worst forms of malignant haemorrhagic fever, however, no trace of albumen may be discoverable, \u2014 a fact recently exemplified in our wards at University College Hospital. \u2014 The notion that purulent deposits may be carried off' through the kidneys is one of long-established popularity among surgeons ; Ambroise Par\u00e9, Desault, and others held the doctrine : the fact is, however, far from being established. M. Rayer has for some years sought in vain for pus in the urine of individuals, in whom the absorption of purulent depositions of various kinds was effected under his own immediate observation. An abundant precipitation of phosphates with mucus and epithelium will, as we have ourselves witnessed, sometimes produce an appearance most strangely like that of pus, \u2014 the microscope and the addition of a little acid readily settle the nature of the deposit. Pus may, however, actually appear in the urine in cases of secondary abscess from purulent impregnation of the blood ; but it is then produced, we believe, in the renal structures themselves, and is not composed of the originally formed fluid translated (with its properties unaltered) through the circulating system into the renal passages. It is for this reason that the narratives of cases of \u201cabsorbed empyema\u201d (with elimination of pus, in substance, through the kidneys,) are, without the test of actual examination of the kidneys, altogether unsatisfactory. \u2014 Cotunnius* endeavoured to explain the presence of albumen in the urine of a dropsical patient, whose anasarca was rapidly diminishing under the use of diuretics, by supposing it due to the direct passage of the serous fluid through the kidneys. But he had not established the absence of albumen from the urine, before diuresis set in ; M. Rayer (as also we ourselves), avoiding this source of error, has failed in detecting albumen in urine, passed concomitantly with the disappearance of dropsical effusion, whenever the fluid had previously been free from that principle.\nSecondly : Albuminuria from morbid states of the genito-urinary organs. (1. Functional.) On the presence of albumen in cases of simple haematuria it is only necessary to observe, that the albuminuria rarely persists for more than a few days after the discharge of blood-disks has ceased ; concerning its appearance in diabetic urine, we shall presently have occasion to speak. (See Sugar.)\u2014The urine of healthy individuals may become albuminous for a short while (for instance, four-and-twenty hours,) after direct or indirect excitement of the urinary passages. We are not quite sure of being right in ascribing the action of certain articles of food and medicinal agents to such intermediate irritation of the kidneys; it is perhaps equally tenable that an altered condition of the blood is, in these cases, the direct cause of the excretion of albumen with the\n* De Ischiade Nervosa Comment. Yienn\u00e6, 1770, p. 30.\nurine. Dr. Christison* \u201chas occasionally known a temporary albuminous impregnation produced in healthy individuals by eating freely cheese, pastry, and such other indigestible articles as are known to have in general the effect of increasing the usual solid ingredients of the urine, and occasioning a large deposit of lithic acid and lithate of ammonia.\u201d We agree with M. Martin-Solon j- that when such consequences follow, individual predisposition must be admitted to exist. Dr. Christison has repeatedly seen the same condition of the urine induced for a time (and we have ourselves had cognisance of the same fact) by the actionof a cantharides blister, when it excited.symptoms of renal irritation. \u2014 That hyper\u00e6mia of the kidney of the simple kind may produce albuminuria, was very strongly maintained by M. Martin-Solon, on the evidence of cases which wanted but the test of post-mortem examination to render them conclusive : the valuable experiments of Mr. Robinson give full warranty to the opinion. (2. Organic.')\u2014It may be considered as yet undetermined clinicallj', whether the urine becomes albuminous in cases of simple nephritis unattended with any of the anatomical changes peculiar to \u201cBright\u2019s disease ;\u201d if it does so, the impregnation is not constant, and is slight in amount. J \u2014 The connection of albuminuria with the disease of the kidney described by Dr. Bright is, on the contrary, after much disputation, thoroughly established. While the error of supposing mere albuminous impregnation pathognomonic of that affection is, on the one hand, perfectly understood ; on the other, the great importance of permanent albuminous impregnation, as a sign of the disease, is recognised. We have never ourselves seen a case of Bright\u2019s disease in which the urine was permanently free from albumen \u00a7 ; but the amount to which it is present is, of course, extremely variable ; we have frequently treated cases in which the coagulation was so complete, that not a single drop of fluid escaped, when the test-tube was turned upside down after ebullition. \u2014 On the various affections of the urinary passages causing impregnation subsequently to the act of secretion (e.g. pyelitis), it is unnecessary to dwell ; of albuminuria depending on ence-phaloid disease of the urinary organs, we have spoken in another work.||\nThirdly : Albuminuria from accidental admixture of genital products. The urine becomes impregnated with semen under a variety of circumstances. The secretion of the testes\n* On granular Degeneration of the Kidneys, p. 36, 1839.\nf De l\u2019Albuminurie, 1838.\nj Becquerel (S\u00e9m\u00e9iologie des Urines) found a little albumen in tbe urine in one of five cases of simple nephritis.\n\u00a7 Dr. Graves (Dublin Journal of Medical Science, No. lx.) maintains that tbe renal alteration may, however, exist without albumen appearing in the urine, \u2014 an idea to be explained probably, by the occasional temporary disappearance of that principle (as we have more than once seen) even in cases pretty rapidly tending to a fatal issue.\n|| The Nature and Treatment of Cancer, p. 386.","page":92},{"file":"p0093.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nescapes into the urethra in certain cases of paralysis and in habitual spermatorrhoea ; and when the bladder is evacuated shortly after coitus (more especially in persons having stricture of the urethra) its contents carry with them a certain quantity of seminal fluid. We doubt that the prostatic secretion alone (the fact has certainly not been proved) leads to distinct albuminuria. Leucorrh\u0153al and catamenial discharges produce it.\nFourthly : Albuminuria from a doubtful cause. Cotunnius* * * \u00a7, Cruickshankf, Nystenf, Andral, Rayer, Martin-Solon, Becquerel, and we ourselves, have found that the urine may contain a variable quantity of albumen during the progress of acute diseases \u2014 a fact which is now matter of familiar clinical observation. M. Martin-Solon shows that the impregnation occurs in about ~th of all cases ; this observer at one time held that the occurrence was of \u201c critical \u201d signification, an opinion he has since correctly relinquished.\u2014 In certain chronic diseases, unattended with any organic alteration of the kidneys, the occasional occurrence of albuminuria has been positively established : in disease of the heart by Dar\u00ab wall\u00a7, Forget ||, and Martin-Solon; in bronchitis and disease of the intestines by the latter observer ; in aneurism of the ventral aorta by Dr. Morrison f ; in phthisis by Toulmouche**,and by ourselves, temporarily. Of the habitual occurrence of albumen in gouty urine, the evidence is insufficient. Becquerel found it in seven of eighteen cases of acute rheumatism, depending rather upon the acute type, than upon the nature, of the disease. \u2014\u2022 In the exanthemata, albuminuria depends on simple renal congestion (resulting from the inaction of the skin) ; or (especially in scarlatina) on the supervention of a form of \u201c Bright\u2019s disease,\u201d characterized by abundant accumulation of epithelium in the tubules.\nThe saliva is another secretion which, containing albumen in extremely small quantity in the natural state (not more than 1.5 in 1000 parts), becomes apparently impregnated with that substance somewhat abundantly in certain morbid conditions. Simon f f found 7.77 per 1000 in the fluid discharged in ptyalism. However, the elaborate analyses of Dr. Wright Jf show that this excess of albumen is not a constant phenomenon ; in a case of ptyalism he found the albumen reach only 0.6 per 1000, and in three other forms of morbid saliva analyzed by him (fatty, sweet, and bilious), the quantity of albumen equalized the average in the fatty variety only.\nThe sweat has been found to contain albu-\n* Op. cit. p. 31,\nf Rollo on Diabetes, p. 444.\nJ R\u00e9cherches de Chim. et de Phys. Pathologiques, p. 253. 1811.\n\u00a7 Cyclop. Pract. Med. art. Dropsy.\nIl Gazette M\u00e9dicale de Paris, vol. v. p. 609. (two cases.)\nDub. Med. Journal, No. xxxvi. 1838.\n** Gazette M\u00e9d. de Paris. F\u00e9vrier, 1839.\ntf Qp. cit. vol. ii. p. 10.\nj j Medical Times, or Der Speichel in Physiol. Diagnost. and Therap. Beziehung, 1844.\n93\nmen by Anselmino in a case of rheumatic fever. Stark asserts that albumen may be detected in this excretion in \u201c gastric, putrid, and hectic diseases, and also on the approach of death, in consequence of the abnormal solution of the solid constituents.\u201d Simon * failed in detecting any certain indications of albumen in the sweat of a person in the colliquative stage of phthisis.\n(b.) Albumen retained.\u2014That granular particles of protein-basis, retained within the tissues, are some of them albuminous, seems a very admissible proposition. The non-plastic protein-substance infiltrating the kidney in certain forms of Bright\u2019s disease, for example, is albuminous rather than fibrinous in all probability. But the difficulty of positively assigning their species to protein-compounds, especially under such circumstances, is sufficiently well known. The mechanism of albumen-precipitation within the body must be of different character from that by which it is effected without the frame, \u2014 at least it is not easy to conceive how the agencies, chemical and physical, which are known to produce precipitation of albumen removed from vital influence, can come into play among the tissues.\nAlbumen appears in the retained and nonplastic state as an important element in the fluid of dropsies ; to avoid repetition, we defer its consideration under these circumstances to Part II., where dropsical products are examined.\n(B.) Fibrin, (a.) In the secretions.\u2014That fibrin should occur in the urine, in association with the other elements of blood, is no more than must be expected in cases of h\u00e6maturia. But it has of late years been found that fibrin sometimes occurs in solution in that excretion independently of any other constituent of the blood. Thus Nassef \u201c knew a Catholic priest who passed, particularly during the night, a large quantity of whitish urine, that coagulated spontaneously in from ten to fifteen minutes after leaving the bladder, and often indeed coagulated in the bladder itself. The patient experienced no debility. On analysis the urine was found to contain a large quantity of fibrin, but no blood-globules.\u201d There were also prismatic crystals of triple phosphate present. Zimmerman J has particularly followed up this subject, and affirms he has discovered fibrin in the urine in endocarditis, pleuritis, pneumonia, bronchitis, rheumatic ophthalmia, periosteitis of the occiput, and erysipelas of the face. Urate of ammonia or uric acid was sometimes present. The fibrin, he presumes, appeared simply as an excretion, sufficient oxygen not having been taken up to decompose it into its organic forms. Zimmerman holds, that in cases of coagulable urine the coagulation will be found to be due to the presence of fibrin quite as often as of albumen, \u2014 a proposition which appears to us utterly inadmissible.\n* Op. cit. vol. ii. p. 109.\nf Brit, and For. Med. Review, vol. xx. p. 75.\nx Zur Analysis und Synthesis der pseudo-plastischen Prozesse; or, Brit, and For. Rev. loc. cit.","page":93},{"file":"p0094.txt","language":"en","ocr_en":"94\tPRODUCTS, ADVENTITIOUS.\n(b.) Fibrin retained. \u2014 The majority of protein-precipitates are probably fibrinous. At least spontaneous coagulation (a quality belonging to them alone) is by far the most readily conceivable cause of precipitation under the circumstances now pointed at.\nFibrin occasionally occurs as a potential precipitate in the fluid of dropsies, a fact which will be further considered in Part II.\n(C.) Casein occurs in combination with fat in so-called \u201cmilky\u201d urine.\n(D.) Globulin is practically unknown (as distinguishable from the other protein-compounds) in the present point of view : it probably forms the substance of some granular precipitates.\n\u00a7 II. Fat.\u2014 Considered in respect of their ultimate physical elements, the varieties of fat (known to occur as morbid products) appear as adipose cells, free-fluid oil-globules (olein); solid fat granules (mainly margarin) ; groups of stellate crystals (margarin and margaric acid) ; rhomboidal plates (cholesterin). Fat may likewise be incorporated in such manner with the' textures as to be only chemically discoverable,\u2014a fact often lost sight of in the examination of morbid appearances : phos-phuretted fat has thus (among other examples of the fact) been found in cancer. Of serolin as a new product nothing is known.\nUnhealthy formation of fatty and oily substance is of almost perpetual occurrence. The fat produced is either similar (when viewed with the naked eye) to that naturally filling the cells of adipose tissue, or more or less completely dissimilar. In the first case the natural adipose structure is simply present in excess, whence arise local or general obesity, fatty infiltration of parts, and lipomatous tumours. In these conditions there is little more than hypertrophy or excessive secretion ; and it is mainly in deference to usage that we shall, in another part of this article, describe lipoma as an adventitious product. In the second case the dissimilarity of the fatty material to natural fat, or the new situation in which it appears, gives it the character of adventitiousness. Here we shall find: (A) certain varieties of fatty infiltration of natural or of adventitious structures ; (B) fatty matters excreted in the semi-fluid state; (C) encysted fats ; (D) cholesteric and laminated fats.\n(A.) Fatty infiltration, (a) Liver. \u2014 The existence of oily matter, as one of the natural constituents of the liver, long since proved chemically by Braconnot, was some years since established with the microscope, by\nFig. 89.\nNucleated particles from the healthy human liver. (After Bowman.)\na, nuclei ; b, nucleoli ; c, fatty globules.\nGluge*, and more recently with greater precision by Mr. Bowman f, who displayed the position of the oil-globules in the elementary cells of the healthy organ. Now fatty infiltration may occur from superabundant deposition of the natural oil, or from that of oily matter differing from this in chemical constitution.\n(1.) The liver, when \u201cfatty,\u201d is increased, in some cases enormously, in size ; its relations of shape remain unaltered. It is, by far the most frequently affected equally through its entire substance ; but we have, in rare instances, seen the infiltration specially implicating islets of the organ ; its colour is pale greenish yellow or faded leaf ; sometimes but rarely studded with reddish points; its elasticity destroyed to such a degree that it pits on pressure ; its consistence greatly diminished; its density decreased to so great an amount that slices have been known to float in water. Very rarely is this condition of the liver coexistent with other morbid changes in its substance ; the vessels and ducts are unchanged in calibre and structure.\nThe fatty nature of the impregnation is sometimes obvious on the most superficial inspection ; the hands and knives brought in contact with the tissue are greased ; and if a thin slice be placed on paper and exposed to heat, the fatty matter melts abundantly, and oils the paper. Gluge was the first to show that these appearances depend upon the accumulation of a multitude of free fat globules, with a small quantity of yellowish granular matter, probably belonging to the colouring matter of the bile. Mr. Bowman discovered the precise seat of the morbid deposition to be the interior of the elementary liver-cells : \u201c instead of containing a few minute scattered globules, the nucleated particles are gorged with large masses of it, which greatly augment their bulk, and more or less obscure their nuclei.\u201d\nFig. 90.\nNucleated particles from the liver affected with fatty degeneration. (After Bowman.) a, nuclei ; b, nucleoli ; c, c, fatty globules.\nWe believe, however, with Mr. Gulliver J, that in this morbid state fat accumulates \u201c in the interlobular fissures and spaces, as described by Mr. Kiernan, or at least around the surface of the lobules, where it forms a distinct buff-coloured boundary to each of them. The ruddy-coloured hepatic lobules appear to diminish in size as the paler fatty substance increases. In a few instances it was principally seated in the centre of the lobules.\u201d Albers \u00a7 taught that the fat depo-\n* Op. cit. Heft i. S. 126. 1838.\nf Lancet, January, 1842.\n% Med. Chir. Trans, vol. xxvi. p. 96.\n\u00a7 Bust\u2019s Magazin, 1839.","page":94},{"file":"p0095.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nsition chiefly takes place in the interlobular cellular membrane which has first undergone hypertrophy : he confounded cases of cirrhosis with true \u201cfatty\u201d change.\nVauquelin found that by exposing slices of fatty liver to a gentle heat, incapable of causing decomposition of animal matter, their composition, as the mean of several experiments, appeared the following : yellowish con-crescible oil, 0.45; parenchyma, 0.19 : moisture, 0.36. This fat unites with alkalies, and forms a soft soap with the usual properties. From a specimen immersed in boiling water by Dr. Bostock*, a quantity of oil exuded, rose to the surface, and, when the water cooled, was converted into a hard white substance, physically resembling tallow. It began to melt at 80\u00b0, and was completely fused at about 110\u00b0; in its chemical properties it generally resembled tallow.\nOf the causes of this condition of the liver little is known. The fact of its frequent existence in France in phthisical subjects, already stated by Bayle and Laennec, was numerically proved by Louis.f This observer found fatty impregnation of the liver in 40 of 120 phthisical subjects, in 9 only of 230 persons dying of other affections ; he also discovered that (uninfluenced by age) its proportional frequency in males and females is as 1: 4. An-dralj, speculating upon these facts, suggests that, inasmuch as, in consequence of the morbid state of the lung, a sufficient quantity of hydrogen is not expelled in the form of pulmonary aqueous vapour, this element is separated in excess from the blood in the parenchyma of the liver, and there helps to form fatty matter. Mr. Bowman surmises, in a similar manner, that it arises from excess of carbon, (which it is the chief office of the liver to throw off from the system,) accumulating in consequence of imperfect respiration. But these conjectures are too exclusive in their bearing. Fatty liver occurs in non-phthisical subjects, whose respiration is naturally performed^ Explanations of this class obviously fail to account for the unequal frequency of the fatty change in the phthisis of climates so closely similar as those of Paris and London ; and leave unaccounted for the greater tendency of phthisical Frenchwomen than Frenchmen to the peculiar change.\n(2.) The liver we have described is the \u201c fatty liver,\u201d per eminentiam. But undue deposition of fat forms a not unimportant feature in other morbid states of the gland. In cirrhosis, for instance, as particularly shown by Gluge|j, Hallmannl, and Valentin**, accu-\n* Bright\u2019s Hosp. Rep. vol. i. p. 114.\nf De la Phthisie, p. 115, ed. 1.\nj Anat. Pathol, t. ii. p. 598.\n\u00a7 This condition of the liver is comparatively very rare, as we have elsewhere observed, (Physical Diagnosis of Diseases of the Lungs, p. 215.) in the phthisical population of this country. Of the numerous tuberculous subjects we have opened within the last four years, (1845,) not one presented this morbid state to any marked amount.\n|| Op. cit.\nDe cirrhosi hepatis. Berol. 1839.\n** Repertorium, 1840.\nmulation of fat, either free or in vesicles, is as perceptible a character of the disease, as obliteration of the ultimate bile-radicles and bloodvessels and atrophy of the lobular structure. But we do not believe, with Gluge, either that this fat-deposition is the solitary element of the diseased state in cirrhosis; or that the \u2018\u2018fatty\u201d state of the liver already described (1) is the first stage of cirrhosis. On the other hand there can be no question that theAtrue history of this common disease is, in respect of its fatty element at least, yet undetermined.\n(3.) There exists a third form of fatty condition of liver, of which we have as yet but little experience, but which may not be passed over in silence. We have now some three or four times found minute crystals of Cholesterin among the hepatic cells, (gathered together in sufficient quantity to render the nuclei of these obscure,) in portions of the gland, of pale fawn tint, flaccid, fragile, and rather greasy in look and feel. In one of these cases the gallbladder was greatly distended with deep-coloured but quite fluid bile.\nQ>.) Pancreas.\u2014The proper texture of this organ is sometimes infiltrated with fat, in such manner as to give it the aspect of being composed of that substance*, \u2014 a condition perfectly distinct from that of mere accumulation of fat between its lobules.\n(c.) Mamma. \u2014 The acini of the mamma are said to be found by Dupuytren similarly affected ; the observation, we think,, requires repetition ; certain it is, at least, that in fatty hypertrophy of the organ the acini continue distinguishable.\nid.) Kidney. \u2014 The kidney is subject to different species of fatty change, which have been confounded by writers under the general title of \u201c fatty degeneration or transformation.\u201d First: in certain cases of atrophy of the renal textures dependent on cyst-formation, or on chronic pyelitis (either of calculous or simple inflammatory origin), abundant accumulation of fat takes place in the cellular tissue surrounding the kidney and underneath the capsule, and encroaches on its proper substance. Secondly : unnatural development of fat may take place amid the tissue of the kidney in connection with similar atrophy, sometimes perhaps as the cause, more frequently as the effect of this morbid change. Thirdly: the kidney, in very rare instances, acquires the colour and many of the properties of \u201c fatty liver,\u201d greasing paper, &c. In a remarkable case recorded by M. Pascal f, the quantity of oil present was so considerable that it exuded from the organ under pressure, almost as from a sponge. No particular symptoms appear to have occurred in connection with this state ; but its symptoms and minute anatomy both require investigation. Fourthly: M. Gluge J, some years since, taught that one variety of alteration, found in the kidneys of persons cut off* with the symptoms of Bright\u2019s disease, was\n* Lobstein, Anat. Path. pi. ix. fig. 1.\nf Journal Hebdomad. 2e s\u00e9rie, t. xii. p. 347. 1833.\nX Op. cit. Zweites Heft, S. 130. 1841.","page":95},{"file":"p0096.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n96\ncharacterized by the deposition of fat-globules in the cortical substance. Of this alteration he recognises three degrees or stages. In the first, deposition of free fat-globules occurs in the cortical substance, unattended with obvious change in the tubuli or bloodvessels. In the second stage, deposition of yellowish altered fat-globules occurs within the tubuli of the cortical substance; the bloodvessels continue unaffected. In the third stage, deposition of peculiar altered fat-corpuscles takes place in rows in the site of the cortical tubuli; these tubuli being themselves destroyed in the same manner as the biliary ducts in the most advanced stage of cirrhosis of the liver. More recently Dr. Johnson* has given a character of precision to our knowledge of the relationship of fat-deposit to the morbid changes in Bright\u2019s disease. He finds : 1. that the epithelial cells of the healthy kidney contain oil to a variable amount ; 2. that an excessive increase of this fat constitutes, primarily and essentially, Bright\u2019s disease ; 3. that the pressure of this fat causes, by a simple mechanical process, the presence of blood and albumen in the urine, and atrophy of the kidney. We are here simply engaged in considering the fact of fat deposition in the kidney, and cannot digress into a discussion on the anatomy of Bright\u2019s disease. But we must venture to add that careful observation has shown and continues to show us, that the compound state, known as Bright\u2019s disease, (renal alteration, albuminuria, and dropsy, with the well-known train of secondary morbid conditions,) may exist without any undue deposit of fat in the kidney in any known form or condition.\n(<?.) Testicle. \u2014 The testis is liable to fatty destruction, the fat accumulating in the oil-globule form without and within the tubules.\n(/.) Lungs.\u2014Of fatty accumulation in the lungs little is known. We have never seen any condition cognizable by the naked eye, referrible to such alteration of structure ; and have not, even with the microscope, discovered accumulated fat in tubercular lungs, except amid the tuberculous matter itself. Under these circumstances we have regarded the fat as appertaining rather to the tubercle per se, than to the diseased lung ; nevertheless it has appeared to us that fat is associated in larger proportion with tubercle of the lung than with that of other organs.\nM. N. Guillot has recently informed the French Institute -f that, while the sum ol fatty matters contained in the foetal lungs varies from 10 to 18 per cent., it falls to 6 per cent, on the establishment of respiration. . He further conceives he has ascertained that in all affections attended with temporary or permanent suppression of respiration in a greater or less extent of lung, the ratio of fat increases in the impermeable tissue. The natural ratio of fat to tissue being seldom more than as 10:100, it may change to even 50: 100.\n* Med. Chir. Transactions, vol. xxix. p. 1. 1846.\nf Comptes Rendus, Juillet, 1847.\nHad the author made these deductions from the examination of phthisical lungs only, the fatty elements of tubercle might have been supposed to account for the excess of fat in the impermeable tissue ; but he affirms that in pneumonia the same phenomenon occurs.\n(g.) Arteries and cardiac valves. \u2014 Of these we have already spoken (p. 87).\n(A.) Muscles. (1.) Voluntary. \u2014 In cases of continued inaction the muscles become infiltrated with fat ; a fact readily ascertainable in those of paralyzed and of rachitic limbs. In old people the muscles of the calf of the leg and the sacro-lumbalis and longissimus dorsi frequently undergo this transformation. It is almost constantly observed in the muscles surrounding joints which are the seats of unreduced dislocation ; and may be seen to accompany the atrophy produced by anchylosis or other causes, and in the case of old ulcers which have for a length of time interfered with motion. In scurvy the muscles sometimes undergo a similar change.\nIn a portion of muscle, appearing to the naked eye totally converted into fat, and weighing 13 drachms, li drachms were composed of muscle, 4 grains of gelatin, all the rest of fat.* The fact, thus chemically shown, that even in the most apparently perfect cases of disappearance of muscular substance, some of this remains, is fully demonstrable with the microscope also. Between and upon the muscular fibres and within the sarcolemma appear fat cells and free oil globules. Gluge has pointed out the existence of saline crystals in rachitic fatty muscles.\n(2.) Involuntary.\u2014Fatty destruction of the heart's substance may coexist or not with deposition of fat underneath the pericardium ; and, as Bizotf has shown, has no connection with superabundance of subcutaneous fat : indeed this is true of the entire class of fatty changes, of which we are now speaking. The deposition of fat is most common on the right side of the organ, in the ventricle much more than the auricle.\nIn these cases there is but a superfluity of natural fat, which encroaches on, and renders soft and atrophous, the proper muscular texture. But there are certain forms of fatty change in which the muscular element itself is the seat of the primary disease, where a mottled dull yellowish aspect of certain portions of the organ is found to depend on accumulation of oil-globules within the sar-colemma.\n(?'.) Tendon. \u2014 Deposition of fat occurs within the sheath, and amid the primitive fibres of the tendons of paralyzed limbs.\n(A.) Nerves.\u2014 The same statement applies to the nerves of such limbs. In cases of atrophy of the optic nerve, fat accumulates within the neurilemma.\n(/.) Bones.\u2014 The bones become infiltrated\n* Cruveilhier, Essai sur l\u2019Anat. Pathol, t. i. p. 186. 1816.\nj- M\u00e9m. de la Soc. Med. d\u2019Observation, t. i. p. 353.","page":96},{"file":"p0097.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nwith fat in a peculiar form of atrophy * * * \u00a7 of their proper texture, which is often attended with fracture. The latter circumstance distinguishes such cases from those of ordinary osteomalacia, wherein (in addition to other characters not belonging to the present head, as, for instance, disappearance of their gelatin-element, M\u00fcller,) accumulation of free oil appears as an important character.\n(m.) Adventitious Products. \u2014 Numerous adventitious products contain fat within their proper substance. Thus fat is a very frequent constituent of urinary calculi, and of various concretions,\u2014for instance, the arterial species. In deposits, (as the typhous, tuberculous, and purulent,) it occurs occasionally in great abundance in the granule and oil-globule forms ; and it forms a constituent of no mean importance (though an accidental one) of various growths. Thus in fibroma and osteoma the total absence of fat is unusual ; and in cancer fatty matter occurs with such constancy as almost to take rank with its essential elements.\n(B.) Fatty matters excreted in the semi-fluid or fluid state. \u2014 (a.) Fat does not exist naturally in appreciable quantity in the urine ; in certain states of disease, however, oily matter is discharged in some quantities with the fluid. Simon and others have discovered fat in the urine of persons labouring under phthisis and tabes mesenterica ; and it is commonly said to be of most frequent occurrence in diseases attended with rapid emaciation. We have ourselves in vain sought for it in numerous cases of phthisis at all stages, and consequently regard its presence as by no means constant. Dr. Elliotson relates the case of a female suffering from biliary calculi who passed about the third of an ounce of oil daily with her urine f : such cases are, however, not to be regarded without suspicion. Fat occurs, occasionally at least, in considerable proportion in the urine of females affected with puerperal fever.\u00a3 Heller \u00a7 found the same principle in three cases of herpes zoster. Fat also exists,\n* The frequent association of atrophy with fat-deposition in various organs (Carswell, Gluge) is as curious as it is positively established; but the mode of connection of the two phenomena has not been fully ascertained, and is probably not constantly uniform. It would appear rational to suppose that the fat-production acts most commonly as the cause (mechanically) of the atrophy with which it is found ; but (to go no further) in certain atrophies of the kidney, the latter is, if not the cause, certainly the occasion of the former. It is a notable fact that in the organ which undergoes the process of senile atrophy to the highest amount\u2014namely, the lung \u2014coexistent fat is not found ; at least, we have sought for it unsuccessfully with the microscope ; it is true that M. Guillot\u2019s mode of investigation might point out fat that had otherwise eluded detection. Be this as it may, however, the same difficulty in determining the relationship of atrophy and other coexistent morbid changes (as, for instance, of serum-accumulation in atrophy of the convolutions of the brain in certain insane persons) is met with, as in the case of fat-deposition.\nf Med. Chir. Trans, vol. xviii.\nJ Bouchardat, Journ. des Connaiss. M\u00e9dicales, Ao\u00fbt, 1843.\n\u00a7 Simon\u2019s Chemistry, vol. ii. p. 320.\nVOL. IV.\n97\nassociated with albumen, in some cases of Bright\u2019s disease, in saccharine diabetes, and in the so-called chylous urine : and there are three cases on record (by Canubio, Alibert, and Graves) in which the fluid was actually milky, containing fat and casein.\n(b.) The f\u00e6ces sometimes contain oily and tallowy-looking matters in large quantities. The circumstances under which intestinal discharge of this kind occurs, are not by any means fully understood. Peculiar functional derangements of the digestive process are sufficient, independently of organic disease, to produce discharge of the kind, whether per an urn or through the mouth.* The f\u00e6ces in diabetes mellitus are remarkable for their large proportion of fat. Dr. Percy found this principle amount to 16.16 per cent, of the dried f\u00e6ces in a case where food of all kinds was taken.f May the alleged fact that grape-sugar is converted into butyric acid by bile, be considered to explain (or at least to illustrate) the occurrence of fat in these f\u00e6ces ? Some of it is probably derived from non-digested food.\n(c.) The saliva occasionally contains \u201c adventitious fatty matter and fatty acid,\u201d according to Dr.Wright J ; he found so much as 3.9 of these principles in 1000 parts of one variety of morbid saliva.\n(d.) The sweat is said to contain fat in the colliquative hectic state ; but we know of no analysis satisfactorily proving the point. \u00a7\n(C.) Encysted fats. \u2014 Fatty matters of different kinds occur in cysts. The chief varieties of these are atheroma (from adppa, pultis) ; meliceris (from mel, honey, and cera, wax) ; and steatoma (from artcip, fat); so called respectively from their pultaceous, honey-like, and suety appearance. The most common seats of atheromatous and meliceric cysts are the scalp and eyelids ; the new matter sometimes accumulates in the sebaceous follicles.\nOne peculiarity of the fatty matter in meliceris and atheroma appears to be the absence of containing cells \u2014 the fat is free. Muller hence presumes that the cyst is formed of the thickened walls of an original single fat-cell, \u2014apparently an unnecessary hypothesis. Besides the fat, there is a granular matter of albuminous nature in these masses.\nAnalyzed by Valentin jj, the following was found to be the composition of this encysted fatty matter : \u2014\nCholesterin ...................... 0.352\nElain and oleate of soda.......... 3.216\nStearin..........................  0.222\nAlbumen and potass ; chloride\nof sodium and lime...........J\nCoagulated albumen................ 5.923\nWater ............................88.715\nSteatomatous matter is most commonly accumulated in the ovaries, between the vagina\n* See the author\u2019s work on Cancer, p. 324. f Quoted in Simon, vol. ii. p. 378.\n\u00ce Loc. cit.\n\u00a7 See Simon, op. cit. vol. ii. p. 110.\n(I Repertorium, 1838, p. 307.\nH","page":97},{"file":"p0098.txt","language":"en","ocr_en":"98\nPRODUCTS, ADVENTITIOUS.\nand rectum, and more rarely about the eyelids, scalp, neck, and prepuce. The matter itself is homogeneous, but differs in consistence in different parts of the cyst \u2014it may be almost fluid in some. Dr. Lever* * * \u00a7 describes a cyst between the uterus and vagina which gave out a quantity of fluid matter, when punctured, that looked like \u201cdripping\u201d when cold. In ovarian cysts steatoma is frequently associated with hair.\n(D.) Cholesteric fats.\u2014Plates of cholesterin f are frequently found in the fluid of hydrocele and of cysts of the thyroid gland. Rayer J found them in a cyst of the kidney, in a subject whose aorta contained several small tumours a little above the bifurcation, seated under the lining membrane, and composed in great part of cholesteric scales. \u00a7 In a female who lately died in our wards with obstructed bowels from stricture of the rectum, a large cyst lying behind the right psoas muscle contained cholesterin in atheromatous-looking patches on the inner surface of its wall : here it was undergoing calcification.\nCholesterin has been found in scales among pus of an abscess near a carious tooth ||, and of an abscess near an anchylosed joint.1 In such cases it disappears from the secreted matters before suppuration ceases.\nCholesterin occurs occasionally in various morbid growths,\u2014 for example, in the different varieties of cancer.\nClosely allied to (if not sometimes identical with) cholesterin in chemical constitution, is a fatty product, for which the name of cholesteatoma has recently been proposed by Midler. This substance occurs in the forms of (1) tumours ; (2) granules ; (3) 'patches ; (4) scales.\n(]). Tumours composed of this material are commonly of the consistence of tallow ; firmer than the brain when found in that organ. They are not lobulated, but frequently mam-millated on the surface ; uneven, with a general tendency to roundness ; surrounded with a capsule of delicate fibrous structure ; varying in size from a walnut to the clenched fist and upwards. Of sixteen recorded cases the brain was the seat of the tumour in seven ; the bones in three ; the utero-rectal cellular tissue in two ; subcutaneous cysts in three ; a large cysto-sarcoma of the breast in one.\nThe interior of the mass has a shining white and semi-transparent aspect, either generally or in some spots only, while in others the white colour is dull. Muller found that the substance shrinks and becomes yellowish by desiccation. All who have observed it describe it as composed of delicate laminae, for the most part\n* Med. Chir. Trans, vol. xxiii.\nf Becquerel and Rodier affirm that the proportion of cholesterin in the blood increases in persons of both sexes from the age of forty to fifty: hence, perhaps, the greater frequency of separation of this fat in old people.\nJ Maladies des Reins, t. iii. p. 541.\n\u00a7 See also Christison, Ed. Med. and Surg. Journ. vol. xxxii. p. 278.\n|| Caventou, Journ. de Pharmacie, t. xi. p. 463. 1825.\nNasse, M\u00fcller\u2019s Archiv, 1840, Heft. iii. S. 267.\narranged concentrically, and easily separated : it is completely extra-vascular.\nThe lamin\u00e6 and the matter interposed between them possess different structures, (a.) The lamin\u00e6 consist of superimposed strata of cells, rendered pentagonal, hexagonal, or polygonal, by lateral mutual pressure, resembling, except in size (they are only half as large, averaging a diameter of .00081 of an inch), the cells of sheep\u2019s fat (fg. 91) ; easily\nFig. 91.\nPolygonal cells of cholesteatoma magnified 290 times.\n(After M\u00fcller.)\nseparated from each other, transparent and pale; possessing neither nucleus nor central granules, and admitted to be hollow, rather from the analogy of sheep\u2019s fat, than proved to be so by observation. The substance forming the cells is distinct in its nature from fat, as it is neither dissolved nor deprived of its laminated appearance by boiling alcohol. (b.) The inter-laminar matter consists of crystals tabular and lamellar. The tabular are in greatest abundance ; generally short, broad, and rectangular, but frequently narrow and riband-like, and probably composed of pure cholesterin (which appears under the microscope in the form of rhombic tables), as acids and alkalies do not affect them.\nThe lamellar crystals look like acicul\u00e6 of stearin from their being gathered into bundles ; but when deposited from their \u00e6thereal secretion they are distinctly lamellar, and pointed at both ends.\n(2.) Granules. \u2014We agree with M\u00fcller in believing that the pearly looking globules described by Cruveilhier in a cancerous growth of the testicle* were very probably composed of cholesteatomatous matter.\n(3.) Patches.\u2014Dupuytren observed patches of this substance on the surface of a urinary fistula ; M\u00fcller a stratum of it covering a cancerous ulcer of the mamma.\n(4.) Scales.\u2014The fluid of hydrocele and of tumours of the thyroid gland frequently contains scales of a pearly looking matter, sometimes collected abundantly at the most dependent part of the cavity. This matter, commonly believed to consist of cholesterin, is not always so composed. Dr. Bostock-f-found it essentially different from adipocere and from cholesterin, not soluble in water or in alcohol, but partially so in \u00e6ther, and incapable of saponification by potash. M\u00fcller found the alcoholic or \u00e6thereal solution of the tuberiform variety yielded no oil on evaporation, but a fine granular fat, probably stearin, with lanceolate lamellar crystals,\n* An. Path. livr. v. tab. i. fig. 2.\nt Med. Chir. Trans, vol. xv. p. 158.","page":98},{"file":"p0099.txt","language":"en","ocr_en":"99\nPRODUCTS, ADVENTITIOUS.\nhaving convex edges converging to a point at either end, as before referred to.\nIn the peculiar softening of the vitreous humour called sparkling synchisis, the sparkling appearance at the bottom of the eye is said (Bouisson) to depend on the presence of molecules of cholesterin.*\nThe development of masses of cholesteatoma takes place, independently of bloodvessels in its substance, by successive generations of layers of cells, each layer being removed from the seat of its formation by that following, precisely after the model of epithelium. The cells being, as far as observation has gone, unprovided with nuclei, and containing no sub-cells in their interior, cannot be considered capable of producing new cells ; the seat of true production therefore, as long as the mass continues to enlarge, remains unchanged to the last.\n$ III. Sugar. \u2014 In a peculiar state of the system, the essential nature of which is as yet enveloped in obscurity, starch-sugar (identical in all properties with glucosef) accumulates in sufficient quantity in the blood to be easily detected in that fluid by chemical analysis. The same substance impregnates the secretions and excretions, \u2014 the urine, the faeces, the perspiration J, the expectoration\u00a7, and (as is inferrible from certain experiments |j) the gastric juice.\nIn this disease (known as saccharine diabetes) the condition of the urine has always clinically attracted the chief attention. Not only is the sugar most easily discoverable in the urine, but this fluid is otherwise strikingly altered in qualities : its specific gravity ranges from 1028 to 1055 1 ; while its amount varies from two or three to seventeen pounds in the course of twenty-four hours. The connection of albuminuria with diabetes is matter of dispute. Cotunnius** observed long since that albumen occasionally occurs in diabetic urine. Sch\u00f6nlein states, that the presence of sugar is preceded by that of albumen, the latter disappearing, while, with the advance of the disease, the former increases in quantity. Th\u00e9nard and Dupuytren, observing coagulability of the urine occur in cases, where the fluid had been excessively abundant and saccharine, regard albuminuria as of favourable augury. M. Rayer j-f has frequently known the change (as might be expected) announce coming dropsy. Fat sometimes exists in sufficient quantity in diabetic urine to render it milky-looking. J J The once popular idea\n* Ranking\u2019s Retrospect, vol. vi. p. 286. f Th\u00e9nard, Rayer, and Bouchardat formerly maintained that diabetic urine sometimes contains an insipid sugar, independently of, or in addition to, the sweet variety ; but later observations disprove the existence of any such body as the insipid sugar, t Nasse, Rhein. Corr. Blatt. No. vi. 1842.\n\u00a7 Francis, Lond. Med. Gaz. Feb. 12. 1847.\n|| Those of Mr. M\u2018Gregor ; vide note, next col.\nThe specific gravity is in exceedingly rare cases not raised much above the healthy standard; Dr. Prout once found it even below this (1015).\n** De Ischiade Nervos\u00e2, p. 31. 1770. ff Mal. des Reins, t. i. p. 151. jj Rayer, in L\u2019Exp\u00e9rience, t. i. p. 664.\nthat sugar takes the place of urea in the urine has been set aside by Mr. M\u2018Gregor\u2019s investigations, which show that the daily discharge of urea may throughout not only equal, but exceed, the healthy average. Deficiency of urea (which sometimes occurs) can only be regarded as accidental.\nVarious theories of the pathology of diabetes have been started. Those of the organic class (gastric, renal, &c.) have hitherto proved inadequate : the most accurate investigations have failed to establish any textural alteration antecedent in development to sugar-accumulation in the blood. Doctrines of the chemical class are in one point of view more entitled to consideration. Rollo originated these by ascribing the disease to mal-assimilation in the stomach \u2014 to decomposition of vegetable food into sugar through the influence of morbid gastric juice. Mr. M\u2018Gregor\u2019s experiments proved the production of sugar in the stomach from amylaceous substances*, and thus gave the appearance of demonstration to Rollo\u2019s theory. Nor can more modern speculations be said to have done much else than to have shaped that theory to the principles of advancing chemistry. Of these speculations it appears well to notice two.\nIn the first of these the argument runs as follows ;\u2014In the natural state of the digestive process sugar is not evolved from starchy matters, the formation of that substance stopping at what may be called the dextrin stage : and further, the economy is doubly guarded against the passage of sugar, used as food, into the secretions : first, by a power on the part of the stomach of transforming sugar ; and secondly, by a similar power on the part of the blood. Now in diabetes, it is assumed, both these powers are lost : swallowed sugar is not converted ; and amylaceous matters are carried beyond the dextrin stage of transformation, and changed into sugar. But this doctrine of the chemistry of the disease appears to fall before the facts, that if much sugar be taken in a state of health, (as by persons indulging in punch to any amount,) the urine is distinctly found to contain sugar : nay, even under ordinary circumstances, sugar has been detected (Buchanan) in healthy blood soon after a meal.\nThe second theory, to which we shall refer, may be deduced from the following document, kindly supplied to us at our request by our colleague Professor Graham.\n\u201c The principal conclusions to which I have been led by a comparative examination of the\n* Feeding a diabetic patient upon beef, Mr. M\u2018Gregor found sugar in the contents of the stomach vomited immediately after a meal, and concluded (a notion accepted by Berzelius as the basis of his own theory) that the protein-compounds had been converted into sugar. The true explanation of the fact seems to be, that in this disease the blood contains so much more sugar than natural, that a certain share is thrown out with the gastric juice, and is of course discoverable immediately among vomited food. It is matter of doubt with the best chemists, whether sugar can be evolved from the much more closely allied substance, fat.\nh 2","page":99},{"file":"p0100.txt","language":"en","ocr_en":"100\tPRODUCTS, ADVENTITIOUS.\ningesta and digesta of diabetic patients, continued in two cases daily without interruption for several months, and for a few days at a time in several other cases, are as follows: \u2014\n\u201c The quantity of saccharine matter found in the urine never exceeded the sugar and starch in the food. On the other hand, the sugar and starch of the food were accounted for in the urine to within one-fourth or one-fifth of the wrhole quantity. As there was always sugar besides in the f\u00e6ces in a sensible, although not considerable, quantity, it appeared to follow that sugar and substances convertible in the stomach into sugar, are, in diabetic patients, nearly if not entirely indigestible; that is, they pass through the biood without being burned and thrown off in the form of carbonic acid and water, as they are in a healthy state. The idea of any portion of the saccharine matter found in the urine being formed from the protein or azotized portion of the food was entirely excluded.\n\u201c The proportion of sugar in the urine has a limit which it cannot exceed, but which varies within a small range in different patients, about 4^ per cent, being the usual maximum. The volume of the urine comes, therefore, to be entirely governed by the quantity of saccharine matter in the food.\n\u201c Although sugar escapes oxidation in the respiratory process of diabetic patients, alcohol is entirely consumed. On one occasion a diabetic patient swallowed twelve ounces of absolute alcohol, contained in a quart of whisky, within twenty-four hours, without a trace of it appearing in his urine or other excretions. Gum arabic also, taken as food to the extent of five or six ounces a-day, did not cause an increase of sugar in the urine, and was probably, therefore, digested. Both alcohol and gum are, like sugar, pure aliments of respiration.\n\u201c It is well known that in the air expired by man, the proportion between the volume of carbonic acid found and oxygen deficient is remarkably uniform, and indicates that an excess of oxygen, nearly constant in amount, is consumed above what is represented by the carbonic acid, due of course chiefly to the oxidation of hydrogen. An amylaceous diet, in which the only combustible element is carbon, tends to reduce this disproportion, while an animal diet increases it. I therefore expected to find a deficient proportion of carbonic acid in the expired air of a diabetic patient confined to an animal diet ; but such was not the case ; the proportion proved to be perfectly normal. This implies a considerable waste of azotized food,\u2014that even the protein-compounds are only partially digested in the system of a diabetic patient. The assimilating power appears, indeed, to be generally deficient.\u201d\nAccording to Mr. Graham, then, the disease is to be understood thus :\u2014In consequence of deficient oxidation of sugar in the respiration-process, that substance (which in the natural state of things is burned off as quickly almost as it mixes with the circulating fluid) accumulates to a greater or less extent in the blood, and its elimination from this fluid is partially\neffected through the secretions, especially the urine. This is a most plausible and clear view of the chemical mechanism of sugar-disease ; but a quid ignotum\u2014the cause of the deficient oxidizing power \u2014 remains in the back-ground, mysterious and impenetrable.\nClass II. \u2014 Plastic Products.\nThis class includes all products possessed of organized arrangement, whether their structure be of a rudimentary or advanced kind; we shall distinguish them by the term Formations. Formations are themselves separable into two very distinct sub-classes; \u2014 the one in which the formation depends for continued existence upon the immediate and direct access of nutritious matter from the blood of the parent organism (Hlastemal Formations) ; the other in which the vitality of the formation is not dependent upon such direct access (Germ-Formations or Parasites). While the products referrible to these two sub-classes differ in their structural characters, in their properties, in their vital actions, and in their influence on the organism containing them, they are no less distinct in their mode of origin. Those belonging to the one sub-class originate in a structureless fluid or blastema ; those belonging to the other spring from a germ. And the distinctive attributes of the two sub-classes may in the most concise manner be put thus : \u2014\nSub-Class I.\u2014Dependent existence ; origin from a blastema.\nSub-Class II. \u2014 Independent existence ; origin from a germ.\nSUB-CLASS I.\u2014BLASTEMAL FORMATIONS.\nThe structureless fluid just referred to is termed blastema (from \u00dfKacrroQ, a germ) in consequence of its being the germinal material from which certain formations are evolved ; and likewise cytoblastema (kvtos, a cell), because an essential process in that evolution is the generation of cells.\nThe source of this material, as of the formative material of the natural elements of the organism is none other than the circulating fluid \u2014the blood.* But there are three possible forms in which the blood may be supposed to furnish the germinal material in question. First, the blood in substance may itself constitute blastema ; secondly, some of the elements of the blood, unaltered in properties, may constitute blastema ; and, thirdly, some of those elements altered in properties may constitute blastema.\nNow, analogy is opposed to the admission of the first of these possible cases : there is no instance of a natural structure being evolved from the blood as a whole. But arguments founded on analogy are valueless, if at variance with the results of direct and satisfactory observation. As matter of experience, then, does blood in substance, unaltered in apparent physical properties, and either retained within\n* Of the chyle and lymph, as suppliers of blaste-mal elements, nothing is known practically.","page":100},{"file":"p0101.txt","language":"en","ocr_en":"101\nPRODUCTS, ADVENTITIOUS.\nor extravasated from the vessels, ever act as a blastema for cell-evolution ? John Hunter, as is well known, held that extravasated blood was capable of organization (by which term he meant vascularization) ; but his statements do not by any means prove that the masses, assumed by him to be simple coagula, were not in point of fact more or less extensively mixed with coagulable lymph, or inflammation-exudation. Others have, however, endeavoured to give support and greater precision to the views of Hunter. Mr. Dairympie*, some time since examining a coagulum (injected by Mr. Busk) seated between the tibia and its periosteum in a scorbutic patient, found its substance permeated by vessels, which he judged to be of new formation. The form, mode of arrangement, and general characters of these vessels, (as we have ourselves seen,) seem to justify the idea that they are really new formations ; but no proof that exudation-blastema may not have been present amid the extravasated blood is adduced by their describer. More recently, Mr. Dalrymplef, not content with ascertaining the fact of vascularization of scorbutic coagula, has succeeded in tracing the progress of cell-development in the substance of such coagula. But if vascularization existed, the humbler grade of organization, signified by cell-production, was to be expected ; and the new observations of Mr. Dalrymple do not remove the objection which in this point of view may be made to the old. Still these observations show very satisfactorily that the presence of blood in substance will not prevent the occurrence of cell-evolution and of vascularization, when the other conditions of its accomplishment exist. J In describing H\u00e6matomata, further on, we shall have occasion to return to this question ; the reader may refer also to our observations on Softened Fibrin in the article on Pus.\nSecondly, the blood-elements comprised under the title of liquor sanguinis, slightly modified in their relations of quantity and in their vital tendencies, are capable of constituting morbid blastema. By changes, such as these, is educed from the blood the fluid called coagulable lymph, the nature of which will hereafter be more fully considered.\nThirdly, certain elements of the blood, more or less deeply modified in essential properties, form the most common species of blastema. And what is the nature of the modification referred to ? Is it physical, chemical, or simply potential ?\n(a.) As far as observation goes, the modification is not of physical character. Formations the most various (just as natural textures the most various) spring from blastemata having the same physical qualities.\n(b.) Of the chemical constitution of blastemata at the moment of production, nothing is known from actual experiment ; but that it is (setting aside its saline ingredients) albumino-fibrinous maybe admitted as matter of inference from the source and mode of its production.\n* Med. Chir. Trans, vol. xxiii. p. 205. 1840.\nf Mecl. Chir. Trans, vol. xxvii. p. 70. 1844.\n$ See the author\u2019s work on Cancer, p. 51.\nScarcely, however, have these blastemata become the seat of cell-evolution than, as is fully established, their chemical composition varies very materially ; while the resulting mass is in some instances essentially composed of albu-mino-fibrinous elements, in others it is of fatty nature ; in yet others it yields gelatin. The question then arises whether the chemical difference detected in any two given morbid formations has existed in their blastemal fluid ab origine, or been effected in connection with the process of cell-germination. In the absence of direct information on the point, it is natural to apply for its elucidation to the phenomena of healthy nutrition. Now, in the evolution of the natural tissues, compounds of various chemical constitutions spring into existence in close juxtaposition from the same blastemal fluid. And this diversity of chemical combination is certainly connected in some way or other with the presence of cells : for one of these vesicles (while the walls of all are, as far as is known, of protein-basis) may be shown to have fat for its contents, another pigment, another a protein-compound, &c. ; whereas, previously to the occurrence of cell-evolution, no such chemical distinctions could be established within the blastema. Chemical changes and cell-evolution are then connected ; but in what manner ? Conceivably in one or other of two ways : the development of cells may be Q)a mere coincidence with the generation of new chemical compounds, or (2) it may be its cause. 1. That it is a mere coincidence; in other words, that the cells are passive, and the blastema itself alone active in the chemical changes, cannot be admitted ; all analogy is against it. Thus the importance of yeast-cells in the phenomena of fermentation is too obvious to be denied even by those, who refuse to accept the view of Schwann that those phenomena cannot occur at all in fermentable matters, unless through the influence of cells. 2. Cell-action then must have some influence as the cause of the chemical changes, and may by possibility be their (a) sole or (\u00df) their partial cause.\n(a) Supposing the cells the sole agents, we must admit that their solid constituents (wall and nucleus) in virtue of an inherent faculty (the so-called metabolic force) form new compounds out of the homogeneous matter surrounding them, this matter being chemically passive in the changes occurring. This was Schwann\u2019s view, and he grounded it on the analogy of the alleged necessity for the presence of cells as a condition sine qua non of fermentation in fermentable matters. But, as Henle has urged, the influence of cells is here exaggerated ; cases are not wanting in which organic matters undergo chemical change through the sole agency of heat or acids, independently of the evolution of cells. And, it may be added, that in the progress of some fermentations, yeast-cells not only do not germinate, but actually disappear, as in the instance of a fermenting solution of pure sugar. (0) It would appear probable, then,\nit 3","page":101},{"file":"p0102.txt","language":"en","ocr_en":"102\nPRODUCTS, ADVENTITIOUS.\nfor this reason that chemical change is in some measure worked out by (and, infer-entially, that chemical differences exist ab origine in) blastemata themselves ; but, even thus, the cells must have an influence secondary only in time, not in importance. Like all membranes placed between fluids of different nature (the surrounding fluid and that contained within them), the cell-wall must be the seat of endosmosis and exosmosis, and the chemical result must be regulated, on the part of the cell, not only by the nature of membrane. or cell-wall to be permeated, but by the nature of the fluid contents of the cell.\n(c.) That the potential qualities of different blastemata differ is perfectly obvious ; existences (such as cancer, pus, tubercle) must be formed from materials endowed with different vital tendencies. Concerning the nature and essence of this potential difference nothing is known with certainty. As respects the process by which its own special character is impressed on each blastema, and the locality in which that process is accomplished, three cases are possible : either the special character is given while the elements of the blastema are still circulating with the blood ; or while those elements are undergoing filtration through the walls of the vessels ; or at both these periods. Now, though it is probable that the filtration process exercises some influence of the kind under consideration, yet it is next to certain that the main influence is exercised on the blastemal elements within the vessels by the constitutional state of the individual,\u2014 that upon this constitutional state, and not upon any local process whatsoever, mainly depends the issue of a blastema, whether it shall be evolved, for instance, into cancer or fibrous tumour, pigment-cells or pus, fat or enchondroma.\nThe blood being the source from which blastema is derived, there are three distinct situations in which it may, \u00e0 priori, be supposed to undergo evolution into structure : (a.) within the vessels : (b.) in the substance of the vascular walls : (c.) outside the vessels. Whether evolution does occur in all these situations requires to be examined into.\n(a.) Certain adventitious formations are unquestionably found occasionally in the interior of the veins, and their presence can only be accounted for in one of two ways, either as the result of the absorption and subsequent germination of certain elements of growths pre-existing elsewhere, or of primary evolution of blastema which had never escaped from the vessels. There can be little doubt that in the great majority of cases intra-venous Formations are produced by evolution of absorbed elements; but it appears probable that they may sometimes spring from retained or non-exuded blastemal elements. It is true, the embryonic production of a fragment of natural tissue within the vessels is an anomaly of nutrition of which no example has, as far as we know, been witnessed ; analogy is consequently opposed to the admission of a germinating force in non-exuded blastema. It is\nlikewise true that, in respect of the simplest form of blastema (the inflammatory) escape from the vessels appears essential to evolution as a general fact ; nevertheless, it is to be remembered, inflammation-products are evolved within the vessels in cases of arteritis and phlebitis, and in the healthy state epithelium is constantly being produced on the internal vascular surfaces. Hence the possibility of retained blastema germinating within the vessels must be, at least provisionally, conceded ; and such germination may be imagined most readily to occur where peculiarities of texture interfere (as in structures of the erectile class) with the process of exudation.*\n(b.) Nodules of adventitious structure have sometimes been met with in the actual substance of the parietes of the veins. The localization of these nodules becomes intelligible on the supposition either that blastema, furnished by the blood circulating in their interior, has germinated during the process of filtration through the vascular coats ; or that the blastema was originally supplied by the vasa vaso-rum. The fact that the nodules in question have been principally met with in veins of a certain size (where exudation does not habitually occur) makes it probable that, in some cases at least, the vasa vasorum are the source of supply.\n(c.) But both localities, so far considered, are rare, though possible, seats of germination ; hence it follows directly that the common site of the phenomenon must be outside the vessels, and indirectly that the process of filtration through those tubes is commonly a necessary element in the generation of a blastema apt for evolution. Hence it is that exudation fluid has been employed as a synonym of blastema in general. Now the possible positions outside the vessels are : \u2014 the intervascular interstices of the various tissues and organs ; the free (or sub-epithelial) surfaces, mucous, serous, and cutaneous ; the surface (and, mediately, by imbibition, the substance) of the extra-vascular tissues ; and, lastly, adventitious surfaces, produced by wounds and other agencies. Now observation (while it has decided that germination does actually occur in all of them) has proved the first-named of these situations to be by far the most common seat of the phenomenon.\nIn those cases, unfortunately restricted in number, in which observation has succeeded in establishing the characters of blastema (as in the instances of induration-blastema and pus-blastema) this fluid has been found homogeneous, almost perfectly transparent, slightly\n* It is clear that what has been spoken of by writers as the \u201c conversion of blood \u201d into the substance of certain Adventitious Formations can be nothing more than an appearance produced by the evolution of primary blastema or of absorbed blastemal elements in the interstices of a coagulum : the idea of an actual change of either blood corpuscle into the cell of an Adventitious Formation is wholly inadmissible.","page":102},{"file":"p0103.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t103\nviscid, and free from solid particles of any kind. And the evolution of all kinds of blastema proceeds in the same manner, as far as hitherto ascertained, until the formation of cells is effected. The successive steps may in general terms be stated to be increase of viscidity, formation of granules, of nuclei, and of cells.* And these various steps cannot be accomplished except in blastema in contact with living animal structure, \u2014 a blastema loses its potentiality either by the death of the textures amid which it is evolved, or by its removal from among them. We place no confidence in the experiments upon which a statement of certain exceptions to this law has been founded, f\nNo matter what be the ultimate destiny of the blastema, the process of its evolution is conducted, then, on the same principle ; but the development of cells sets a limit to this identity of process. The vital qualities of the cells differ, and affect the function and end of these, in three principal modes ; and, according as each of these prevails in any given blastema, will the product generated (solid or semi-solid) present peculiar characters. These three modes of cell may be described as follows.\nFirst, the cells once developed may be altogether inapt for life, incapable either of undergoing such changes in physical, chemical, and vital constitution as shall qualify them for sustaining a permanent existence, or of generating the elements of new cells previous to their own destruction. They are consequently acted upon physically and chemically by the surrounding materials : they are either dissolved by the fluid with which they are associated ; or, disintegrated and broken down into nonproductive granular matter, they lose all trace of the attributes of organization. Cells of this kind may be termed evanescent and retrograding.\nSecondly, the cells may be deficient in the faculty of permanency requisite for the formation of tissue ; while, on the other hand, they possess the power of generating the elements of new cells (or of causing indirectly the generation of those elements) previously to their own disappearance, \u2014 cells endowed in turn with a similar generative force. These cells consequently present the characters of the formative stages of evolution, never those of perfectly evolved structure. To this kind of cells the title non-permanent and vegetative may be applied.\nThirdly, the cells may possess an inherent force, qualifying them to pass through the necessary steps towards the formation of structure more or less closely resembling the natural tissues, and in this evolved condition they are destined permanently to remain. These cells appear likewise to be destitute of\n* The production of fibres without the intervention of a cell-stage (an exceptional phenomenon, if the entire system be taken in view) w\u00fcl find its place elsewhere.\t,\nt Helbert, de exanthematibus arte factis. G\u00f6tt. 1844.\nthe power either of generating or of indirectly causing the generation of the elements of new cells similar to themselves; they may therefore be termed permanent and non-vegetative cells.\nFrom cells of one or other of these three kinds all blastemal formations are produced. Formations produced from the evanescent cell are non-stromal, and may be termed deposits ; those from the vegetative cell are stromal, and may be termed groivths ; those from the permanent cell are stromal, and may be termed pseudo-tissues.\nOrder I. \u2014 Deposits.\nDeposits are deficient in the characters of texture ; they possess neither permanent fibre, nor definite arrangement of parts, septa, nor loculi ; and are insusceptible of vascularization. They tend to produce eliminatory action and ulceration in the seats they occupy ; and are prone to appear, mainly through the influence of so-called \u201c diathesis,\u201d in several parts of the frame simultaneously or consecutively. The substance of all deposits is per se non-inocu-lable ; we say all, because, though the point has not been, to our knowledge, experimentally tested in regard of the typhous and diphtheritic species, there can be little doubt that the proposition applies to them as to the others. But certain varieties of one genus of deposit (pus) are, on the contrary, readily inoculable through the agency of certain associated principles called viruses (see Pus). In such cases, be it observed, the propagation of the disease in no wise depends on the cell of the fluid.\nIn the order Deposits (constituting transition products from the non-plastic protein-precipitates to formations of higher attributes) we place the following genera : typhous, tuberculous, purulent, melanic, and diphtheritic products.\n\u00a7 1. TYPHOUS DEPOSIT.\nIn the form of continued fever anatomically characterized by alteration of structure in the glandular textures of the small intestine, a peculiar substance of new formation (as first accurately described by M. Louis*) is discovered in the cellular membrane between the mucous and muscular coats of the patches of agminated glands of Peyer. The proportion of cases of continued fever of intestinal type in which this deposit occurs, has been differently estimated from less than one third of the cases to nearly the entire number. We have found this matter homogeneous in aspect, of pinkish or yellowish hue (the former accidental), and from a sixth to a quarter of an inch thick ; we have always seen it more or less firm and tenacious, and never succeeded in catching it in its earlier stage of fluid blastema. Examined under the microscope by B\u00f6hmf it appeared utterly destitute of\n* Roederer and Wagler (De morbo mucoso, p. 332.) first noticed this substance thus : \u201c ne sein el tarnen elevatos [folliculos coagmentatos] et materia mucos\u00e2 obscur\u00e8 cinerea repertos vidimus.\u201d\nf Brit, and For. Med. Rev. vol. i. p. 524.\nH 4","page":103},{"file":"p0104.txt","language":"en","ocr_en":"104\tPRODUCTS, ADVENTITIOUS.\nstructure, and so it commonly is. But in some instances, in addition to granular matter lying in a structureless substance, remnants of cells may be detected, and, more rarely still, nucleated cells of unbroken outline, some larger, others smaller than the red blood-corpuscle. Epithelium cells are often accidentally present, as also oil globules.\nThat the main element of this material is of protein-basis may be inferred from its general properties. Buzzorini* gives its composition from direct analysis as follows,\u2014fibrin, phosphate of lime, lactate and hydrochlorate of soda, and traces of other salts of the blood. Under the microscope acetic acid renders the basis more or less transparent ; its effect on the cells seems to vary.\nWe have seen matter of similar character in the mesenteric glands ; and we cannot affirm that the intestine and these glands are its sole seats, not having looked for it in other parts of the body of typhoid patients.\n$ 2. TUBERCULOUS DEPOSIT, OR TUBERCLE.\nTubercle, when in that condition that its properties are most clearly marked, and when at that period of its development that no dissentient opinions are held as to its nature, possesses the following characters. It is an opaque substance of yellowish colour; sufficiently firm yet friable, of little tenacity, and resembling cheese very nearly in point of consistence ; inelastic ; without particular smell ; accumulated in small masses varying in size from a pin\u2019s head to a hen\u2019s egg, of homogeneous aspect all over their divided surface ; exhibiting no vessels ; insoluble in water, and if mixed therewith quickly subsiding to the bottom. And these are the properties of a material which, in respect of its physiology, is characterized by its tendency to become soft after it has existed for a variable period in the condition of firmness, and to induce various changes in the natural textures with which it is connected, changes eventually effecting its own complete disintegration and elimination.\nNothing can be more true than that tubercle is homogeneous ; but this may or may not be true of a tubercle. A tubercle of the brain is perfectly so ; each particle is the counterpart of all others composing it, and for the simple reason that the natural structure, wherein the new matter has found a nidus, has been pushed aside in proportion as that matter has accumulated. A tubercle of the lung, again, may also upon rough inspection appear homogeneous ; but if closely scrutinized with the naked eye, or, better, with a lens, it will be found that the section of the little body is marked by lines of a different tint and aspect from its general substance. This arises from the enclosure of some of the tissue of the organ by the accumulating tuberculous substance.\nTubercle may be deposited in isolated masses, or, it is said, be infiltrated through the stroma of the various tissues. ( 1.) When\n* Der Typhus, 1836, S. 87.\noccurring in masses it is usually of tuberiform shape, and the mass has sprung either from a single centre of formation, or from the concrescence of several smaller tubercles formed in the close vicinity of each other. It has long been a subject of dispute whether tuberiform tubercle occurs in the encysted form. Laennec held the affirmative ; and M. Louis follows on the same side. Dr. Carswell \u201c feels perfectly satisfied that the term encysted, whether applied to pulmonary tubercle or to tubercle in any other organ, is almost always incorrect. In the lungs encysted tubercle is a deception, the distended walls of the air-cells having in all probability, in almost every case, been taken for cysts. In like manner the dilated bulbous extremities of the biliary system have been described as cysts of the liver containing tuberculous matter.\u201d* The evidence furnished by Laennec and M. Louis is defective ; the latter observer never saw the presumed appearance in the lung but once, and no description is recorded from which the accuracy of the explanation offered may be ascertained. t On the other hand, Dr. Carswell\u2019s objection turns altogether upon his special notions concerning the almost limitation of tubercle to the mucous surfaces. We have ourselves never seen encysted tubercle in any structure of the body, if by the term be understood tubercle contained within a cyst, which has acted as its formative organ. But we have seen in very rare instances in the lung, and, comparatively speaking, somewhat more frequently in bone, tuberculous matter surrounded by a more or less complete membrane, strongly assimilable in properties to the pyogenic membrane of abscesses, and, like it, obviously formed consecutively to some at least of the matter it invested. Such we believe to be the key to the comprehension of \u201c encysted tubercle,\u201d especially taken in conjunction with the fact that true abscesses in the lung have not unfrequently been mistaken for tuberculous accumulations. To the class of secondary cysts is also to be referred that species of membranous investment occasionally formed round tuberculous matter while undergoing a process of inspissation.\nThe tuberiform shape is so common in tuberculous masses that its cause has been made matter of inquiry. By some persons presumed to depend on a moulding faculty intrinsic in the tuberculous substance (an obviously absurd notion), it has been referred by Schroeder van der Kolk and Dr. Carswell to the influence of the surrounding parts. The latter observer well shows that, in point of fact, this shape is less common than has been maintained, and scarcely occurs except in the brain and cellular membrane, and under certain circumstances in the lung. Stratiform deposition is that occurring on serous surfaces in layers ; ram form, that observed in the bronchi and biliary system.\n* Illustrations of the Elementary Forms of Disease, Fascic. Tubercle.\nf Louis on Phthisis, Walshe\u2019s Transi. Reprint, p. 426.","page":104},{"file":"p0105.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n(2.) Infiltrated tubercle has been described rincipally in the lung, and is here said to ex-ibit two kinds of appearance ; (a) the grey, and (b) the gelatiniform. (a) There are occasionally found in the lungs irregular masses of variable and, it may be, considerable size (five inches in diameter even) of greyish semitransparent aspect, homogeneous, shining, and without distinct structure ; such appearances are generally seen towards the apex of the organ, and may exist in very rare cases independently of any acknowledged form of tuberculous deposit ; slices of texture thus affected sink in vrater, are moist on the surface, dense, and compact. In the midst of such masses it is sufficiently usual to discover a number of small specks of yellow opaque tuberculous matter ; these increase in number and size, and thereby gradually cause the disappearance of the grey matter. Now it is admitted on all hands that the characters of this alleged tuberculous infiltration are extremely like those of chronic pneumonia; and in our mind it is extremely doubtful whether the morbid state be anything more than a particular form of that inflammation. M. Louis draws attention to the following points as distinctive of chronic pneumonic induration:\u20141. Instead of being transparent, the affected tissue is opaque ; 2. instead of being homogeneous, it is traversed by thick white septa ; 3. the indurated parts are more compact than in the presumed tuberculous infiltration. But in acknowledged chronic pneumonia all these characters are subject to a great variation in amount; and the formation of yellow tubercle proves nothing in either direction, as there is no reason why such formation should not occur in a tissue infiltrated with induration-matter. (b) Of the gelatiniform tuberculous infiltration of Laennec, it is sufficient to say that no doubt can be entertained as to the fact of his having described, under this name, infiltration of common exudation matter with excess of serosity, sanguineous or not. Tubercle does, however, occur in the endosteal texture of bone in the infiltrated form.\nThe microscopical constitution of yellow tubercle may be described as follows, at least according to the observations we have ourselves made. (1.) Granular substance exists in abundance in tuberculous matter ; large masses of soft consistence sometimes consist almost solely of it ; and, as the process of softening advances, it abounds likewise; when of well-defined characters and abundant, it constitutes a very distinctive element of tubercle. The granules are dark, of yellowish brown tint, heaped up in masses, varying in size from about l-4th or l-5th of that of the red blood corpuscle (say\tor Tsioo \u00b0f an\ninch) to the merest points. Some of them, undissolved by acids, alkalies, or ether, are of modified protein-basis ; others, soluble in hot ether, are of fatty nature : the latter are sometimes, though rarely, absent altogether. (2.) Cells.\u2014Cells, though probably always existent in tubercle at some stage of its develop-\n105\nment, are not always to be found, or to be found in very minute proportion only, in specimens examined. In some cases they apparently constitute the entire tuberculous mass. We have found them sometimes of circular form, and rather flattish ; sometimes irregular in shape and with rounded angles, never caudate, and nearly averaging in size that of the white blood-corpuscle. They contain a variable number of granules scattered without order through their substance, but generally leaving a free circlet at the periphery. We have never seen a distinctly defined nucleus within them ; acetic acid simply renders the cell-wall more transparent, and exhibits the granules more clearly. (3.) Irregular particles. Shapeless particles, flat, pale, and on an average of less size than the cells, are sometimes seen. These are probably, in part at least, the walls of disintegrating cells ; whether they eventually go to form granular matter is a point, open to inquiry, but appears to us probable. With these the substantial constituents of tubercle, are sometimes accidentally associated. (4.) large fat globules; (5.) plates of choiesterin ; (6.) amorphous saline particles ; (7.) melanic cells and granules.\nNothing having the attributes of a stroma can be detected in tuberculous matter; but a semitransparent substance, more or less solid, slowly soluble in acetic acid, absolutely structureless and amorphous, holds its elements together. Neither does tubercle ever contain vessels of new formation ; and the imprisonment by tuberculous deposit of natural capillary vessels, still pervious, is comparatively rare and accidental ; there is a tendency, constant in action, and eventually irresistible, to obliteration of the vessels around and amid which the blastema of tubercle is thrown out. A new vascular system, we are aware, has been found to originate in the vicinity of tubercle ; but this development takes place within common inflammatory exudation matter. In the same way there may be found on the confines of tuberculous matter compound granule-corpuscles, pus-corpuscles, with, of course, the ultimate elements of the tissues implicated.\nIn the same natural texture with such tuberculous matter as we have now described, are very frequently found certain small bodies varying in size from that of a pin\u2019s head to a very small pea, of greyish-white or greyish tint and glistening aspect. These bodies are known as the semi-transparent grey granulation ; and their affinities to yellow tuberculous matter have been a theme of constant disputation from the period at which tubercle first became the subject of close study. While some regard them as products of common inflammation (Schroeder van der Kolk, Andral) ; while visionaries are found (Kuhn*) to maintain that their relationship is closest to the Nema-zoa of Gaillou (a class of beings forming a link between vegetable and animal existences) ; while a reasoner habitually most cautious (Carswell) regards them in some situations \u2014 the lung \u2014 as an admixture of mucus and true * Gaz. Mdd. de Paris, t. ii. p. 342. 1834.","page":105},{"file":"p0106.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n106\ntubercular matter, in other situations as an admixture of the same matter and coagulable lymph ; the majority of observers hold them to be actual tubercle in an early stage of development. The latter opinion under certain modifications, we believe, for reasons which will presently appear, to be the true one.\nThese bodies occur in different organs and textures in association with yellow tubercle ; they are more or less transparent, and, though in their own substance of light greyish colour, their translucenc\u00ff sometimes gives them in appearance the tint of the circumjacent structure; their section exhibits a smooth and close surface ; hard as cartilage almost in some instances, and in variably remarkable for firmness ; in general outline seeming roundish, yet in reality of somewhat angular form ; and adhering so closely to the adjoining tissues that they cannot be removed without particles of these, they have a striking tendency to accumulate in groups.\nNow the motives for connecting this production pathologically with yellow tubercle, and regarding the one as a phasis of the other, are derived as well from (a) naked-eye observation and considerations of general pathology, as from (b) microscopical examination, (a) Common yellow tubercle appears in the substance of the grey granulation at a certain stage of its existence, and gradually (in the lungs and in bone for example) fills the entire space it had occupied. In the lungs the grey granulation follows the same topographical course as yellow tubercle ; originating in the upper regions, it migrates downwards ; and the quantity of the one, as of the other, is greatest at the apex.* Grey granulations are found mixed with yellow tubercle in various organs, and so rare is the development of the one without the other, that M. Louis f only encountered grey granulations without yellow tubercle five times, and the latter without the former once. The material composing the grey granulation also occurs in the form of shapeless masses, and when so deposited (as in the lungs and lymphatic glands) also becomes the seat of yellow tubercle. (b) Microscopically considered, the elements of the granulation prove the relationship of the two products. A hyaline substance, non-stromal, holds together cells, identical with those already described, mixed (sometimes) with melanic matter in small quantity, and the elementary fibres of the implicated tissue (doubtless the objects mistaken in the lung by Kuhn for vegetable filaments). The proper granular matter of tubercle alone is absent, or present in very minute proportion only. The disintegration and breaking up of the cell-structure, and the exudation, further, of blastema, which, incapable of furnishing cells, generates granules, cause the appearance of yellow opaque amid grey semi-transparent tubercle.\nIt appears, then, that the two conditions, grey and yellow, are stages of each other. But\n* In acute miliary tuberculization, however, the grey granulation, scattered equably through the various parts of the lung, is deposited in an isolated manner.\nj- On Phthisis, Transi, p. 2.\nis this sequence necessary ; must grey matter precede the yellow in the order of evolution ? No : for in some textures, as the lymphatic glands, grey matter is very rare ; in others, as the brain, it is not, as far as we know, ever seen, though yellow tubercle is not of very uncommon occurrence there in infancy ; and, lastly, in the lungs, tubercles are sometimes found of the minutest conceivable size, yet yellow throughout their entire substance without the least grey appearance. It follows, then, that the ordinary first or grey stage may be to all seeming passed over,\u2014an idea by no means repugnant to reason, inasmuch as such a state of things would naturally occur wherever a peculiarly low crasis of the system leads to primary production of granular matter in excess and unusually rapid disintegration of cells.\nAnother kind of granulation occurring in the lungs, first described by Bayle, and by him supposed to be composed of adventitious cartilage, has been by almost all writers confounded with the common grey production. This variety is, we believe ourselves justified in affirming, of great rarity ; at least we have met with but one example of it\u2014some years since at the Hospital for Consumption. In this instance the granulation was of round or oval form, as large as a good-sized pea (all present very uniformly so), of dull white colour, opaline without yellow points, present in moderate numbers, disseminated equably through all parts of both lungs, not grouped, but deposited solitarily, producing no visible change in the circumjacent texture, and unassociated with yellow or grey tubercles. Bayle, maintaining the obviously erroneous opinion, just stated, of their anatomical nature, connected these bodies pathologically with phthisis ; Laennec regards them as a modification of the common grey granulation; our own opinion on the point is unformed.\nAmong the numerous published analyses of tubercle, we have for some years been in the habit of referring to that of Preuss* as at least the most elaborate in existence. According to the results of this analyst, one hundred parts of tuberculized pulmonary substance consisted of\nWater...........................79.95\nTuberculous matter .\t.\t.\t13.52\nFibrous residue, vessels, bronchi, &c. 6.53\nOne hundred parts of the fibrous residue consisted of\nFat .\t.\t.\t.\t.\t.\t4.13\nSubstances yielding gelatin by boiling .\t.\t.\t.\t.\t. 20.67\nSubstances yielding no gelatin by boiling........................75.20\nThe tuberculous substance itself, without water, contained :\nSubstances soluble in hot alcohol only.\nCholesterin.....................4.94\nIn cold alcohol and not in water.\nOleate of soda .... 13.50\n* Preuss, Dis. Inaug. Tuberc. Pulmon. Crudorum Analysis Chemica. Berol. 1835.","page":106},{"file":"p0107.txt","language":"en","ocr_en":"In cold alcohol and in water.\nA peculiar substance (Phi/matin)\nChloride of sodium .\nLactate of soda Sulphate of soda\nIn water hut not in alcohol.\nCasein .\t...\nChloride of sodium .\nSulphate of soda Phosphate of soda .\nNeither in alcohol nor in water.\nCasein (altered by heat) .\nOxide of iron ....\nPhosphate of lime\t.\t.\t* - 65 11\nCarbonate of lime\t.\t.\t. f\nMagnesia .....\nSulphur...........................\n99.91\nPhymatin (<pvfm, a tubercle ; like pyin, the discovery of Gueterbock,) is described as a peculiar extractive matter, not precipitated from its solution by extract of galls, very little by neutral acetate of lead and nitrate of silver, but, on the contrary, very copiously by basic acetate of lead ; sulphate of copper gives no precipitate, according to Gueterbock ; a white flocculent one, according to Preuss. The main protein-constituent of tubercle appears, from the above analysis, to be casein. But numerous chemists question the correctness of this analysis, precisely in respect of the casein ; and it certainly appears proved that Preuss had not furnished sufficient evidence of the nature of the protein-compound contained in tubercle. Scherer* has endeavoured to establish the relations of this organic material to protein, and dwells upon the fact that according to the locality of the diseased product this may be theoretically formed by adding to or taking from protein a varying number of atoms of oxygen, hydrogen, and carbon. The formula of protein, as given by different chemists, it is to be remembered, varies, \u2014 its very existence is made matter of question ; we are, therefore, unable to discover in what manner the chemistry of the formation of tubercle can be considered to be advanced, or to be likely at present to be advanced, by speculations of this class. The insignificance of such hypotheses becomes apparent, too, from the fact that some of the analyses of tubercle differ as much from others as these do from the analyses of cancer !\nM. Boudetf finds, with respect to its organic constituent, that tubercle yields albumen and a matter analogous to casein, under the action of cold water, and is reducible to a substance having the characters offibrin ; he further discovers that casein, insoluble in crude tubercle, becomes soluble eventually through the development of alkali: a series of propositions more striking than satisfactory.\n'\t* Simon\u2019s Chemistry, vol. ii. p. 430. 1846.\nf Bulletin de l\u2019Acad. Royale de M\u00e9decine, t. ix.\np. 1160.\n107\nTubercle is insusceptible of growth, properly so called : it increases in size by accretion of new particles or by gradual coalescence of minute masses, at first separated from each other by appreciable intervals. In the lung the latter mode of enlargement is invariably observed, where the tubercle is of any size ; hence the constancy of septa, as already referred to.\nTubercle,having subsisted for a variable time in the firm (or, as it is called, crude) state, tends to undergo either of the following changes :\u2014(1.) to become invested by a cyst ; (2.) to decay by a process known as softening.\n(1.) In certain situations, more especially the bronchial and mesenteric glands and bones, tuberculous matter, undergoing gradual inspissation, occasionally becomes invested with a cyst (of fibrinous origin), which cuts it off from the surrounding textures, and renders it, comparatively speaking, innocuous.\n(2.) When tuberculous matter has existed for a certain but variable period in the state of firmness or \u201c crudity,\u201d it in the vast majority of cases softens. In this new state its physical characters are either very closely similar to those of thick deep-yellow pus, or (which is more common) it seems to consist of two materials, the one soft, friable, and caseiform, the other more or less watery and transparent, mixed together in variable proportions. Commencing by possibility at any part of the tubercle, this process commences more commonly towards the centre, or at least within the area of the tubercle, than on its confines.\nThe process of softening must either be of intrinsic or extrinsic origin. Laennec, looking on tubercle as vascularized, presumed the change to be intrinsic, and dependent on some morbid condition of vascular action ; an hypothesis which existing knowledge refuses utterly to justify. Other pathologists taught that all changes in the consistence of tubercle depended on actions going on in the surrounding textures \u2014 suppurating, infiltrating, disintegrating. The latter doctrine is doubtless correct in part ; a tubercle, softened at the periphery or even in its central parts, when these are permeated by natural textures, has in many instances simply undergone disintegration from saturation with fluids produced by those textures. But when a large mass of tubercle (as in the brain or in a lymphatic gland) liquefies in the centre, where it is absolutely beyond the reach of influence from the circumjacent tissues, some intrinsic change has evidently occurred. And this intrinsic change seems assimilable to that effecting softening of fibrinous clots in the veins, and is in intimate nature probably chemical.\nTubercle, once deposited, is not necessarily a fixture in the locality it occupies ; on the contrary, its removal from the body is frequent, and occurs under different conditions and in different manners. It is effected ; (a) probably by simple absorption ; (b) by absorption combined with so-called \u201c transformation (e) by elimination.\n(a) Existing knowledge concerning the simple absoipiion of tubercle is far from satis-\nPRODUCTS, ADVENTITIOUS, r.\nI 8.4*6","page":107},{"file":"p0108.txt","language":"en","ocr_en":"108\nPRODUCTS, ADVENTITIOUS.\nfactory. Our own belief (which is firm) in its occurrence rests upon the following facts and arguments. 1. Rabbits submitted to influences which, experience has proved, unfailingly lead to the development of tubercle in the liver and elsewhere, have subsequently been placed in conditions favourable to health, eventually been killed, and no traces, or the merest traces, of tubercle been discovered in their bodies. (Jenner, Baron, Carswell.) 2. Miliary tubercles, developed in the substance of pleural or peritoneal false membrane, disappear in cases where the latter becomes cellulo-serous in texture. 3. Tuberculous matter disappears from the substance of enlarged strumous glands. 4?. We have seen and satisfactorily observed cases of tuberculization of the bronchial glands in children, in which (while the local and general symptoms of phthisis were fully developed, and the physical signs of marked enlargement of the bronchial glands were no less distinct) recovery in respect of symptoms has occurred, coevally with modification and ultimately disappearance of those physical signs. Such cases are unfortunately rare. 5. And, again, we have found the physical signs of induration at the apex of a lung in persons labouring under the local and general symptoms of phthisis, and belonging to a tainted family ; and these signs have totally disappeared in company with the train of local and general symptoms. The event is, no doubt, singularly rare ; and the disappearance of induration-signs may, by the sceptical, be referred to the cessation of congestion. But congestion has its special signs, which were not present in the cases we refer to ; and congestion at the apex is, in the very great majority of cases, of tuberculous origin. 6. Andral and Reynaud attempt to trace certain furrowed and excavated appearances of pulmonary tubercles to a process of absorption, \u2014 but they do this dubitatively, and the point has not been investigated by others.\n(b.) Of the removal by absorption of the animal ingredients of tubercle, while saline particles are deposited in abundance (so-called \u201ctransformation\u201d), no doubt can be entertained. The gradual change of the tuberculous matter may be traced from a condition of mere desiccation with greasiness to the feel, to that of osteo-petrous substance. The traces of animal material may eventually almost wholly, if not wholly, disappear ; for Th\u00e9nard found that while \u201c crude\u201d tubercle contained 98.15 per cent, of animal and 1.85 of saline matters, cretaceous tubercle furnished but 3.0 per cent, of the former and 96.0 of the latter.\nThe production of this change in tuberculous matter is very frequently (but certainly not always \u2014 witness the case of the mesenteric glands) connected with the presence of common plastic exudation in the surrounding natural texture. This exudation-matter gradually hardens, eventually assuming the fibrous condition, and possessed (like all similar exudation) of strong contractile properties, probably facilitates the absorption of the enclosed tubercle by the pressure it exercises.\nBut absorption may proceed further. The cretaceous, calcareous, or osteo-petrous substances, representatives of bj'gone tubercle, sometimes totally disappear; and, at a later period still, the plastic fibrinous substance is itself removed. The part where all these changes have occurred (in the lungs for example) may even appeal' healthy; but on close examination puckering (parenchymatous, we mean, not pleural) is discovered in a spot, where obliterated vessels and bronchial tubes converge, as the indelible evidence of the morbid conditions that have preceded. This puckering and obliteration have (as we believe erroneously) been ascribed to the cicatrization of cavities.\n(c.) The elimination of tuberculous matter by excretion is effected from free surfaces, or from the stroma of parts and organs.\n1.\tExcretion of tuberculous matter, without breach of surface in the part supplying it, occurs in the uterine, renal, and pulmonary passages,\u2014never, so far as we have ourselves observed, in the intestines. The occurrence is, under all circumstances, rare.\n2.\tThe elimination of tubercle from the stroma of parts involves the destruction of tissue by an ulcerative or gangrenous process. Such elimination takes place either when the cretaceous change has occurred, or independently of any such change. Of the former (the rarer of the two) the escape of cretaceous masses from the bronchial glands through an ulcerated opening in the trachea, furnishes a striking example ; the expectoration of such masses from the lungs themselves is extremely rare, while, on the other hand, these organs supply the most important illustration of elimination of unchanged tuberculous substance.\nSoftening of tuberculous matter being complete, the natural textures contained within the area occupied by that matter have likewise lost their consistence, as a result of infiltration with morbid fluids and of imperfect nutrition. Ulcerative destruction readily sets in; minute bronchial tubes are in consequence opened ; through these the softened matter and (as is proved by microscopical examination) fragments of the parenchymatous fibrils and capillaries of the lung are evacuated. An excavation (cavity or cavern) in the pulmonary substance is the result.\nWhen a cavity is of recent date, its walls, smooth and even, are commonly lined, more or less completely, with plastic exudation, fragile, whitish, and opaque ; but the pulmonary tissue is in some instances bare and unprotected. The walls of cavities of old date, firm and resisting, are lined with a membrane, divisible into two strata\u2014the external dense, greyish, and fibrous, the internal soft and velvety, deposited continuously or in patches on the inner surface of the former. Or (as existed in one-fourth of the old cavities examined by Louis) the walls may be totally free from any membranous investment. The walls are uneven, irregular, and coated commonly by bands composed of pulmonary substance (rarely containing permeable vessels) studded with tuberculous","page":108},{"file":"p0109.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t109\nmatter. Such cavities generally communicate with others, and always with bronchial tubes.\nCavities vary in size from that of a nut to very nearly that of the lung itself ; the edges of the lobes being rendered continuous by pleural false membrane, and the pulmonary texture destroyed from base to apex. They form first at the apex, and more readily at its posterior than at its anterior aspect, and very rarely advance 'pari passu in both lungs. When of recent origin they contain pus and softened tubercle, with or without fcetor, in the different conditions already described. When of old date, on the contrary, they contain a dirty, thin, greenish fluid, with grumous particles suspended in it, and stained, or (as is most common) not stained, with blood. In rare instances fibrinous coagula, firm and adherent* * * \u00a7, which may even be the seat of vascularization j-, are found within them ; and still more rarely portions of pulmonary substance, either gangrenous J or free from such change. Vegetable productions of low type are often to be found amid the contents or upon the walls of cavities of a certain age.\nThe course and event of cavities are points of extreme interest.\n1.\tTheir most common course by far is to increase in size, through communications formed with softening tubercle on their confines.\n2.\tThey become stationary, the tuberculizing process having ceased in their neighbourhood. The double membrane lining them acquires more and more perfectly the characters and properties of the structures forming the inner wall of fistul\u00e6 ; and they cease to exercise deleterious influence of any serious kind. The cure of phthisis is sometimes, according to Laennec, accomplished in this manner; but it is obviously necessary for the cure of the disease, not only that the cavity should itself become innocuous in the manner described, but that tuberculization should cease in the rest of the lung \u2014 that the rest of the lung should be healthy. Now we regret to be forced to state that during a search of several years carried on under peculiarly favourable circumstances, we have failed to discover a single example of this fortunate coincidence ; nor do we believe (while to deny its possibility would be rash) that evidence has ever yet been furnished of its actual occurrence. \u00a7\n* Univ. Coll. Museum.\nf Louis.\nj Some time since a patient of ours expectorated a fetid mass, about the size of a large pea, presenting under the microscope, and even to the naked eye, the characters of pulmonary tissue. This is the only instance of the kind that has ever occurred .to us.\n\u00a7 M. Louis relates a case (Op. cit. Transi, p. 19, case 3) in which a solitary excavation lined with pseudo-membrane of recent origin, existed at the apex of one lung in the midst of healthy tissue ; and considers it presumable that, if the patient had survived a short while longer, the membrane in question would have assumed the fistulous characters we have above described : under these circumstances a cure of phthisis would have been accomplished. But in the first place it was not accomplished ; in the second it appears extremely doubtful\n3.\tThat tuberculous cavities are capable of cicatrizing, and that they actually do cicatrize with very considerable frequency, was taught by Laennec, and has since his time been almost universally accepted as matter of established doctrine. We must nevertheless affirm that we have ourselves in vain sought for a single specimen of cicatrized tuberculous cavity ; nor can we avoid deliberately questioning the fact of such cicatrization ever occurring.\nThe shape of fistulous cavities, the smoothness and polish of their internal surface, the fact that atmospheric pressure must act constantly on that surface, and, in fine, their structural analogy to fistul\u00e6 in other parts of the body, form so many \u00e0 priori arguments against the possibility of cicatrization. Laennec saw their force ; but certain observed facts led him to disregard them, and admit the reality of partial and complete adhesion of the apposed walls of cavities. These facts are as follow.\n(a.) In the latero-posterior part of the upper lobe of a particular lung appeared a deep depression, containing a material solid and resisting. From the centre of this depression a white opaque lamina, about half a line thick, and of cartilaginous consistence, extended inwards, divided into two parts, and then reunited, thus forming a small cavity, which was filled with a yellowish-white, opaque, friable substance, much drier than common tuberculous matter. Here was (according to the assumption) a partially closed pulmonary cavity ; and, be it observed, Laennec never saw more than one such case.\n(\u00df.) In the upper part, especially, of the upper lobes, Laennec frequently saw bands or nodules composed of condensed cellular or \u201c fibro-cartilaginous\u201d tissue, with a depression on the superjacent pleural surface, of variable depth, puckered, firm, and uneven, and with adhesion of the pleura at the corresponding point; the converging bronchial tubes being somewhat dilated in the vicinity, and obliterated in the exact site, of those bands cr nodules. Further, these bands or nodules were always situated at the depth of half a line, a line, or two lines at furthest, from the surface of the lung; and were or were not distinctly continuous with substances of similar nature on the surface of the pulmonary pleura. Here were the assumed evidences of complete closure of cavities, \u2014 the puckering and thickening on the pulmonary surface showed that cicatrization had occurred underneath, but did not (as Laennec was often erroneously said to have maintained) in any measure constitute the actual substance of cicatrices.\nBut it may be objected to this doctrine : \u2014 that the superficial puckering is often seen, where subjacent cellular bands or nodules cannot be discovered ; \u2014 that it frequently\n(for reasons which M. Louis has anticipated, but not, as we think, satisfactorily set aside) that the excavation was of tuberculous rather than of purulent origin ; and in the third the eventual assumption of the fistulous characters, in this particular case, is matter of hypothesis.","page":109},{"file":"p0110.txt","language":"en","ocr_en":"110\tPRODUCTS, ADVENTITIOUS.\nexists at the base of the lung, where cavities are excessively rare ; \u2014 that such puckering is so common that, if it really signify closure of cavities, this must be admitted to be an every-day occurrence\u2014an admission to which the laws of general pathology and special clinical experience are equally opposed ; \u2014 that the alleged cicatrices are always (as insisted upon by Laennec himself) either actually under, or only a line or two distant from, the pulmonary surface, whereas cavities are frequently seated deeply in the lung ; \u2014 that Laennec\u2019s clinical evidence in support of closure of cavities is exceedingly defective, and that were cicatrization so common, as on his principles it must be, the opportunity of tracing the progress of contraction during life would frequently occur, whereas it has certainly never yet occurred to ourselves, nor (so far as we are aware) as matter capable of demonstration to any one else.\nLaennec\u2019s anatomical facts were correctly observed, but he misinterpreted them pathologically. The cellulo-fibrous bands or nodules he noticed appear, in truth, to be formed in either of the three following ways. (1.) They are primary productions, generated quite independently of tuberculization ; \u2014 results of local inflammation perfectly assimilable to the bands permeating more or less completely the entire substance of the lung, in certain cases of general chronic sub-inflammation of the organ. (2.) They are produced in the manner already explained (p. 108), in connection with tubercle undergoing absorption. (3.) They are altogether eoctra-pul-monary productions, and their apparent position within the parenchyma of the lung, a fallacy more or less easily exposed.\nUnder all these circumstances their alleged direct relationship to cavities is matter of pure imagination ; but the last mentioned condition of things only (which has been insisted on principally by M. Fournet), needs to be dwelt upon here.\nAs a preliminary point, let it be observed that viscera invested with serous membrane are liable to undergo indentation by the contraction, and in the site, of plastic exudation. Even the liver, dense as it is, we have occasionally seen pretty deeply indentated in this manner ; more frequently is this observed in the spleen, but still more so (obviously from the yielding character of its texture) in the lung. Now, in the particular cases we have in view, the following points may be traced. I. Pleurisy occurs, local or general, with or without liquid effusion. 2. The resulting plastic exudation penetrates or not into sulci on the pulmonary surface formed by creasing ; these sulci are deeper if liquid effusion ha's occurred, than under the contrary circumstances. 3. The plastic exudation is thicker at some points than others, and there excess of depression takes place, because its own contractile force, and the force resisting atmospheric (excentric) pressure, are both greatest there. 4. Processes from this superficial exudation penetrate into the sulci (we\nhave seen them three quarters of an inch long). 5. The thinner peripheral portion of the plastic exudation on the pulmonary surface becomes by-and-by cellular in texture, eventually undergoes more or less complete absorption, and the immediately subjacent portions of lung rise up on the removal of the pressure ; the central and thick part of the exudation (itself become meanwhile more or less distinctly fibrous in texture) appears deeper than ever in the lung, while the perfect adhesion of the edges of the sulcus in which it lies, renders the illusion complete as to its being seated in the actual substance of the lung. 6. The adjoining pulmonary tissue may be simply condensed, or may be solidified with infiltrated plastic exudation ; in either case (but especially the latter) obliteration of the minute vessels and bronchi takes place. The pulmonary tissue, yet beyond this, may become emphysematous.\nThe more frequent occurrence of these appeai\u2019ances at the apex than elsewhere, is the obvious consequence of the great proportional frequency of local pleurisy there, \u2014 itself dependent on the frequency of irritation set up by tubercles in the neighbourhood. The condition of the minute bronchi in the implicated parts, is of itself a strong argument in favour of the doctrine we have set forth ; those tubes are contracted and obliterated as they would be from pressui'e and disuse, they are not abruptly cut across, as they would be were Laennec\u2019s cicatrization-theory in accordance with facts. According to M. Fournet, the deep sunken, fibrous nodule may become the interstitial seat of puriform or of calcareous deposition. In this way he explains Laennec\u2019s solitary example of partially closed cavity, already referred to. We have not seen this condition ourselves : the thing is no doubt possible, but it must be very rare. In taking leave of this question we would observe, that the nature of this work has prevented us from giving it the full development it really merits, but we trust enough has been said to make the main fact intelligible. That fact is doubtless disheartening to the therapeutist ; and we should regret any active part we may have taken in establishing it, did we not look forward on some other occasion to proving, that anatomical cure by absorption, in the manners already described, is of more common occurrence than is generally supposed.\nMany of the influences, irritative and mechanical, exercised by tubercle on surrounding textures, have been spoken of in the foregoing pages ; the generation of new vessels attending the progress of tuberculization in the lung, will be touched upon in the section on New Vessels in another part of this article.\n\u00a7 3. PURULENT DEPOSIT, OR PUS.\nPus is a fluid of whitish-yellow or greenish colour, and homogeneous aspect ; of faint, peculiar smell, when warm ; inodorous, when cold ; of creamy consistence ; and of sweetish, or sometimes saltish, taste.","page":110},{"file":"p0111.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nIll\nPus consists of a liquid part (liquor puris) holding in solution organic principles and inorganic salts ; and of a solid part (corpuscles) held in suspension in the liquor puris. These constituents separate spontaneously, after removal from the body, with a degree of slowness increasing as the purity of the pus ; when the liquor puris is in excess, the corpuscles sink rapidly. The corpuscles are not separable from the liquor puris by filtration. Pus does not naturally contain gas of any kind (J. Davy). Its specific gravity ranges between 1042 and 1021, the weight most commonly observed being about 1030.\nFour kinds of organic corpuscles are found in pus : (1.) Proper pus-corpuscles ; (2.) Py-oid corpuscles; (3.) Granules ; (4.) Compound granule-corpuscles.\n(1.) The proper pus-corpuscle is a body of tolerably spherical outline, unless when accidentally flattened or otherwise altered in shape by the pressure of adjoining corpuscles ; its edge, slightly dentated, as we have commonly seen it, may be perfectly even ; its surface finely granular-looking. The corpuscle is (commonly, but not always,) moderately transparent, subjacent bodies being visible through it, as is particularly obvious when a weak iodine-solution has been added to the fluid. The diameter of the corpuscle varies from the TgJjJ\u00f6 to the\t\u00b0f an inch,\u2014averaging about\nthe -g-oVo* ^ts substance is somewhat elastic. It never, as far as we have seen, presents a narrow edge to the eye, in the manner of the red corpuscle of the blood.\nThe contents of the corpuscle are semifluid and solid. The semi-fluid substance seems of slightly gluey consistence. The solid contents are the nucleus or nuclei. It was long taught that if the pus examined be recent, and chemically unchanged, the nucleus is not perceptible even with strong magnifying powers. This is now known to be erroneous ; we have, with a glass magnifying only 400 diameters, detected a nucleus in laudable pus of neutral reaction, immediately after removal from the body.* But, under the influence of dilute acetic acid, the nucleus is more fully brought into view, and is seen close to the cell-wall, in the form of a bipartite, tripartite, or quadripartite body (more rarely a single one), all the divisions of which lie nearly on the same plane side by side. Each division of the nucleus is smooth, circular, or slightly oval, and biconcave. The central depression, which exists as a consequence of its biconcave form, either appears opaque, while the surrounding part is clear and transparent, or the former is transparent and the latter opaque,\u2014differences depending on variation of the focus of the microscope. The surface of the nucleus is very finely granular ; its diameter varies from the to the tnroo \u00b0f an inch.\n* The facility of its discovery depends upon the transparence and thinness of the cell-wall ; and the amount of these, upon the youth of the corpuscle. In our work on Cancer (fig. 6) are figured nuclei visible without the aid of acetic acid.\n(2.) Under the name of pyoid, M. Lebert* distinguishes a corpuscle smaller than that just described ; spherical in shape, tolerably transparent, rather of solid than liquid consistence ; containing from four to ten granules or more in their interior, and wholly unprovided with nucleus, acetic acid simply rendering the corpuscle more transparent. These bodies, resembling most closely the cells of tubercle (p. 105), are larger and more spherical than these : so great is the similarity, that M. Lebert was at first led to consider the pyoid corpuscle peculiar to tuberculous pus ; but, subsequently finding it (as we have also done ourselves) under circumstances excluding the idea of tubercle, has relinquished this notion.\n(3.) The elementary granule seen in pus is of spherical shape ; it is never cupulated, so far as we have seen, and is less than half the size of the nucleus of the pus-corpuscle, averaging the \u25a01-4-|0.Tr of an inch in diameter. These granules are obviously not, as was once maintained, detached nuclei floating in the liquor puris. They are either single and solitary, or (less frequently) collected in irregular groups. Their composition varies, as they are sometimes soluble in aether, and sometimes exhibit the reactions of a protein-compound ; this chemical difference is not always connected with any physical peculiarity, which the eye at least can detect.\n(4.) The compound granule-corpuscle (compound inflammation-globule; Gluge) does not occur in large numbers in pus ; many drops may be examined without a single one presenting itself. This corpuscle is of spherical, and slightly irregular, form, ranging from tsV\u00f6 t0 TT7T\u00dc \u00b0f an inch in diameter (fig.\nFig. 92.\nCompound granule-corpuscles (magnified 400 diams.).\na, in the natural state, diam. = Tg'35 to yygg of an inch ; b, corpuscle about to undergo rupture, the involucrum being more transparent, and the granules larger, darker, and more prominent ; c, a corpuscle treated with dilute acetic acid, the involucrum being rendered transparent, and several nuclei appearing in its interior.\n92) ; and composed essentially of granules and an involucrum. The involucrum is not dissolved by water, and s mply rendered transparent by acetic acid ; the granules vary from ten, to twenty or thirty, or even many more in number. Occasionally the action of acetic acid discloses a single, double, or multiple nucleus lying close to the involucrum. The granules are likewise kept in situ by a fluid of thickish consistence, in which, if few in number, they may be seen to move. The course of formation of these corpuscles seems to be, \u2014 agglomeration of granules from exudation matter, investment with a membranous wall, production of a nucleus.\n* Physiol. Patholog. t. i. p. 46. 1845.","page":111},{"file":"p0112.txt","language":"en","ocr_en":"112\tPRODUCTS, ADVENTITIOUS,\nFat occurs invariably in more or less quantity in pus, and exhibits itself under the microscope, under the forms of molecular granules, as above referred to ; oil globules ; crystals of cholesterin.\nSaline crystals occasionally occur in pus, especially in certain unhealthy varieties of the fluid. When they exist, some peculiar circumstances have probably caused unusually rapid, or otherwise modified, evaporation of the liquor puris.\nInfusoria (monads and vibrions, especially the vibrio lineola) occur in pus : we are unable to affirm whether their presence is always an evidence of decomposition in the pus itself. The attempt, made by Gruithuisen, to distinguish various fluids by the characters of the infusoria developed within them, has not led to any satisfactory results.\nPus, when recent and healthy, has a slightly alkaline reaction ; we have known it neutral, however, in cases where there was no reason to believe any chemical change had occurred. It readily becomes acid from the development of an acid \u2014 the lactic it is supposed : the change from one to the other reaction, evidently depends, in some cases, on a primary change in the constitution of the pus at the moment of generation ; for we have found pus from the same wound, sometimes alkaline, sometimes acid, though taking all precautions to ensure its examination at the moment of production.\nThe published analyses of pus are extremely numerous. Among the most recent and carefully conducted are several by Dr. Wright*, of which the following may be selected as specimens ; it is clear that the chemical constitution of the fluid must vary somewhat with the locality from which it has been derived, inasmuch as pus can very rarely be obtained free from minute quantities of the textures or secretions in connection with which its production has occurred.\n\tPus from a Yomica.\tPus from a Psoas Abscess.\tPus from a Mammary Abscess.\nWater\t894.4\t885.2\t879.4\nPatty Matter\t17.51\t28.8\t26.5\nCholesterin\t5.4 j\t\t\nMucus\t11.2\t6.1\t\nAlbumen -\t68.5\t63.7\t83.6\nLactates, carbonates, sulphates, and phosphates of soda, potash, and lime -\t9.7\t13.5\t8.9\nIron -Loss -\tA trace. 3.3\t2.7\t1.6\nSome of the discrepancies in the results given by various experimentalists, doubtless depend in no small degree on the differences in the manner of conducting their analyses. Making allowance for these sources of error, it may be inferred that liquor puris consists\n* Medical Times, January, 1845.\nof water varying in proportion from 76 (Von Bibra), and 82 (Dumas), to 90 (Lassaigne, Pearson, and Von Bibra*) per 100, of dissolved albumen, of fibrin, fat, and extractive matters. A peculiar principle (pr\u00e9cipitable by acetic acid and by alum) has been assigned to pus, under the name of pyin, by G\u00fcterbock : that such a special substance exists independently of the means employed to procure it, has been questioned or denied by Valentin, Dr. John Davy f, and others. At the present hour the real presence in pus of the principle, described under this name, is admitted by chemists ; it is said (probably pro tempore) to be tritoxide of protein. Glutin is enumerated by Martins J among the constituents of the pus of empyema ; its existence must be an exceptional occurrence. Phosphoric, hydrochloric, and lactic acids in union with lime, potassa, soda, magnesia, and ammonia, form the ordinary saline elements of the fluid. Oxide of iron, though put forward as a constant ingredient by Cruickshank, Koch, Krauss, G\u00f6bel (in the horse), Pearson, and G\u00fcterbock, is in all probability only present in instances of accidental admixture of blood.\nThe micro-chemical properties of the pus-corpuscle are important. Pure water exercises no obvious influence on it for days, even, except that of rendering the nucleus more visible, and slightly increasing its size by passing through the cell-wall by imbibition. Saturated sugar-water, blood, mucus, and saliva, unless (as observed by Henle) the latter be acid, produce scarcely any alteration in the corpuscle. Urine gives it an extremely ragged outline in the course of a few days (earlier if it be alkaline), and eventually breaks it up completely. Alcohol slightly corrugates, without dissolving it. Under the action of acetic acid the corpuscle loses its granular appearance, commonly undergoes a change of bulk ; and the distinct outline of the involucrum fades away, while the nucleus, simple or compound, becomes clear and distinct. What is the nature of these changes ? The removal of the granular aspect of the corpuscle is not readily explained. We were at one time disposed to regard it as produced by the simple unfolding of the involucrum, caused in turn by imbibition of the fluid re-agent, \u2014 believing that the granular appearance arose simply from a corrugated state of the surface of the involucrum. But the uniformity of the granular appearance, its constancy of occurrence, its extreme delicacy, and the fact that it is not removed altogether, no matter how distinctly the corpuscle be swollen by imbibition, appear to throw doubt upon this view, and render it more probable, if not actually certain, that it depends on the presence of molecular matter within the involucrum ; \u2014the change of bulk is sometimes one of increase, sometimes one of decrease, \u2014 a difference which has appeared to us traceable to the\n* Untersuch, \u00fcber einige verschiedene Eiterarten. Berlin, 1842.\nf Physiological and Pathological Researches.\nX Annalen der Pharmacie.","page":112},{"file":"p0113.txt","language":"en","ocr_en":"113\nPRODUCTS, ADVENTITIOUS.\nvarying degrees of dilution of the acid. That the involucrum fades simply, without being, as was at one time supposed, destroyed, is commonly obvious on simple inspection ; it appears as a sort of thin, transparent halo round the nuclei. But, were there any doubt, this would be removed by the addition of solution of iodine *, which restores the clear definition of the cell-wall. The fading of the involucrum is, however, an early stage of solution ; for, if much acid be added, the halo disappears and cannot be restored. In respect of this disclosure of the nucleus three opinions have found their supporters : (a.) that a simple or compound nucleus, pre-existing in either form, is simply rendered visible by the acid ; (b.) that it is exposed and, besides, split up into parts; (c.) that it is an appearance altogether produced by the acid. That the first of these opinions is the correct one, appears (if on no other grounds) from what has been said in a previous page on the discovery of the nucleus in recent unchanged pus.\nMineral acids, if dilute, do not dissolve the corpuscles ; if concentrated, dissolve them completely. [Caustic alkalies form a jelly with them ; their carbonates, as also muriate of ammonia, change them similarly but more slowly. The action of the latter on pus was observed by J. Hunter on a large scale, and ascribed by him to coagulation of the liquor puris. Dr. J. Davy showed, by allowing the corpuscles to settle, decanting the supernatant fluid, pouring some of the muriate upon this, and observing that no viscidity followed, until corpuscles had been added, that the change depended upon these. Dr. Wood f ascertained that the muriate causes the corpuscles to adhere with some closeness to each other.\nPus-corpuscles contain a very little phosphate of lime, and consist essentially of a protein-compound. Their constituent substance has been given the special title purium by Koch, purulina by Michelotti ; a mode of naming it which must be abandoned if, as Lehmann and Messerschmitt maintain, the nucleus and involucrum belong to two different varieties of protein, \u2014 the former being composed of venous, the latter of arterial, fibrin, J But this view is, it is scarcely necessary to add, itself far from being established, \u2014 as also that of persons who (imitating Ascherson) hold the centre of the nucleus to be composed of fat, and its peripheral part of albumen.\nPus differs chemically from blood in the states of health and of hyperinosis in the proportion of its ingredients, much more than in their nature \u2014as might readily be imagined. But quantitative analyses are as yet so imper-\n* The corpuscles, and especially the nuclei, attract the iodine from the fluid in which they swim ; for, while they darken, this fluid loses its yellow-brown colour.\nf De puris natura atque formatione. (Berol.)\nj Medicin. Vierteljarhschrift von Roser and Wunderlich, 1842, S. 247. The same writers regard the molecular granules of pus as composed of yet another variety of protein-compound, resembling Keratin.\nVOL. IV.\nfeet, that very different general inferences may be deduced from them according to the selection made of published analyses; \u2014 it is true this may also in part depend on the actual variation in the proportions in different specimens of pus. Thus we may prove by one set of experiments that pus contains more water than healthy, and \u00e0 fortiori than hyperinotie, blood ; and, by another, that pus is on the contrary a more concentrated fluid than either. And whichever be the opinion adopted, theoretical explanation and support may readily be found for it. The following general inferences are likewise, we confess, to be accepted with caution.\nPus contains more albumino-fibrous substance than the liquor sanguinis of either species of blood, less than the blood in mass, comprising the red corpuscles. The latter point obviously depends on the fact that the corpuscles are, as such (unless accidentally and in very minute proportion), retained within the vessels ; whereas pus is formed outside them. But how comes it that pus contains proportionally more albumino-fibrous material than the liquid part of the blood \u2014 that part of the blood which is exuded in inflammation, and which forms the substance for the evolution of the purulent matter ? The peculiarity (as suggested by Lebert) is probably due to partial solution of the red-corpuscles in the liquor sanguinis, and transudation ol that dissolved substance ; an explanation not, we may observe, without apparent connection with the established fact of the decrease of red corpuscles in hyperinotie blood. To this source (as well as to extravasation) ma}7, perhaps, be referred the occasional appearance of a little iron among the elements of pus.\nFat is much more abundant in pus than in blood ; the high ratio of cholesterin in the former (as ascertained by Valentin Von Bibra and Wright) comes in confirmation of the fact established by Becquerel andRodierf, that the ratio of cholesterin in the blood is always increased in inflammation. The saline constituents of the two fluids do not differ very materially.\nPus possesses a remarkable power of resisting decomposition ; at the end of months some corpuscles may still be found unchanged, among others that are dissolved. It even retards the putrefaction of substances with which it is brought in contact, as shown by the experiments of J. Hunter and Everard Home. The latter observed that pieces of flesh placed in fresh pus underwent gradual diminution of weight, and eventually solution, without any evidence of putrefaction being manifested. Ultimately, pus does putrefy however ; the occurrence of the change being much hastened by the presence of blood, mucus, or other organic fluids. Acidity, as already hinted, is one of the earliest signs of the change.\n* In one of Valentin\u2019s Analyses (Repertorium S. 307,1838) the proportion of cholesterin is so high as 11.86 per 1000.\nf Gazette M\u00e9dicale de Paris, 1844.\nI","page":113},{"file":"p0114.txt","language":"en","ocr_en":"114\nPRODUCTS, ADVENTITIOUS.\nThe various appearances of pus have given rise to its classification into the creamy, curdy, serous, and slimy varieties (Pearson) ; one obviously unfit to represent the existing state of knowledge. It seems better to consider pus as of two kinds : I. Simple ; II. With added characters,\u2014the added character being derived either from (A) Substances of known nature, natural or morbid ; or from (B) Substances of unknown nature, called viruses.\nThe pus-corpuscle has uniformly the same character in all descriptions of pus. The distinction of the varieties above enumerated, therefore, can only be microscopically effected (if it can be effected at all) by means of su-peradded elements ; and most valuable these are as diagnostic of its seat and production in many instances.\nThe varieties of pus comprehended in the class (B), differ from those in the class (A), in being inoculable, \u2014 a character dependent not upon any peculiarity of their cell, but upon the associated intangible \u201c virus.\u201d Some of the varieties of the class A possess, however, what may be called pseudo-inoculability, namely, those in which certain parasites are present. The pus of scabies is thus to be propagated by means of its entozoon ; that of porrigo by its entophyte ; but it is clear that the associated pus has in reality nothing to do with the transmissibility of the diseases.*\nThere are three semi-fluid matters, which it is important to distinguish from pus, namely, mucus, softened fibrin, and fluid holding epithelium in suspension. The distinctive characters most to be relied on are as follow: (a) Mucus. (1.) Pus mixes with water, being at first equally diffused through it, so as to give it a yellowish tinge ; subsequently, the corpuscles fall to the bottom, and leave the supernatant fluid clear and colourless. Mucus does not mix with water, but eventually renders it slimy. (2.) Pus forms an emulsion with acetic acid, from which, after a time, the nuclei of the corpuscles are thrown down as a yellow sediment, while the involucra are dissolved. Mucus is coagulated by acetic acid, and forms a membranous flocculent mass without mixing with the acid ; at the same time it becomes less slimy and more consistent. (3.) Pus forms a ropy mass with the caustic alkalies, or with their carbonates. (B. Babington.) Mucus, on the contrary, is rendered thinner, and partially dissolved by them. (4.) Pus contains fat removeable by ether, sometimes in such quantities as\n* Donn\u00e9 describes an animalcule, under the name of Tricomonas vaginalis, as peculiar to the female syphilitic discharge, and constituting the infection-agent. But it is not found in the male, and is often absent in the female ; its powers in the latter quality may be more than doubted. Froriep (Notizen, 1837, No. 25. p. 40.) thinks the animalcule, peculiarly connected with the female genitals, but not specially with syphilis ; and regards it with Ehrenberg (Notizen, 1837, No. 28. p. 88) as a species of acarus. This matter requires revision ; it has even been suggested that Donn\u00e9 and his followers have mistaken ciliated epithelium-scales (to which indeed the figure of the former bears much resemblance) for animal cules.\nto render it inflammable; mucus contains none. (5.) Air bubbles in pus collapse the moment they are formed ; in mucus they remain for a time\u2014for days even\u2014unaltered. (6.) Equal parts of concentrated sulphuric acid and pus form a dull brown-red solution, becoming paler and turbid by the addition of water ; mucus, on the contrary, forms \u00e4 pale brown fluid with this acid, which remains clear and becomes colourless on the addition of water. (Brett and Bird.) (7.) According to Preuss, pus (as also tubercle) is distinguishable from mucus by containing iron (which may be shown by inc\u00e9ration and digrating the ash in gum, hydrochloric acid, diluted with five parts of distilled water, and then adding a few drops of ferro-cyanide of potassium) : but in point of fact the presence of iron is due to accidental admixture with blood. (8.) Pus pressed between two plates of glass and held before a candle, presents an iridescent appearance ; no such effect is observed with mucus. (Young ) The state of knowledge concerning the two alleged principles, mucin and pyin, is too unsettled to allow of just inferences being drawn from the presence or absence of either.\nVarious attempts have been made to distinguish pus and mucus by means of the proper corpuscle of each. The difficulty experienced in the detection of distinctive characters gradually led to the suspicion that the corpuscle of both fluids might be one and the same thing ; and the inquiries of several competent persons appear at length to have distinctly established the fact, that healthy mucus contains no special corpuscle, but that, under the very slighest irritation of a mucous surface, pus, with its special cell, is thrown out, which cell had been mistaken for one peculiar to the natural secretion of mucous membranes. The presence of a bougie in the urethra for a very short time suffices to cause the production of muco-pus.* The abundance of epithelium-scales in mucus is sometimes a useful aid in the diagnosis : the nuclei of these scales set free may, doubtless, also have been sometimes mistaken for special corpuscles.\n(b.) Softened Fibrin.\u2014 The semi-liquid matter frequentty found in the centre of coagula in the veins and heart, was long confounded (from its colour, consistence, and easy miscibility with water,) with pus ; notoriously so by MM. Gendrin, Andral, Cruveil-hier, and Magendie. It had been more or less confidently affirmed, however, by MM. Dupuytren, Burrows, Davy, and others, that this matter really consisted of softened fibrin, and not pus, when Mr. Gulliver-j' gave support to this notion by pointing out the following peculiarities, distinguishing the substance in question from pus : 1. It is not rendered ropy by caustic volatile alkali. 2. It presents no iridescence when pressed between plates of glass before a candle. 3. Under the micro-\n* That is as far as the generation of pus-corpuscles is concerned ; the production of liquor puris is a more elaborate process.\n+ Med. Chir. Trans, vol. xxii.","page":114},{"file":"p0115.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t115\nscope it is mainly composed of a finely granular mass, and often contains large, irregular, flabby particles, with globules of various sizes. But these globules bear but a very small proportion in number to those in pus ; and, on the addition of acetic acid, they soon disappear, except a few which seem more compact, and require a longer time for solution : they are probably altered blood-corpuscles. 4. Softened fibrin more readily becomes putrid than pus. Fibrin removed from the body and subjected to a blood-heat, begins to change into matter, such as that now described, in forty hours.\nWe have had numerous opportunities of satisfying ourselves of the general accuracy of these observations of Mr. Gulliver; but we cannot accede to the notion that the yellowish-green, soft, sometimes almost diffluent coagula, frequently seen in veins (coagula which, according to the spirit, if not the absolute letter, of Mr. Gulliver\u2019s doctrine, should consist merely of softened fibrin and accidentally-imprisoned blood disks), never contain, and hence never consist, in part, of pus. We have more than once discovered fully-formed and well-conditioned pus-corpuscles in such coagula, which, upon mere naked-eye evidence, we had regarded as wholly composed of softened fibrin. We refer here to cases where no signs of inflammatory (or other) alteration exist in the coats of the vein, and where those coats appear to have nothing to do with the appearances referred to ; for the corpuscles appear chiefly, or it may be altogether, in the centre of the coagula. Now such cases seem to prove one or other of the following three propositions : That corpuscles exist, having all the micro-chemical characters of those of pus, yet in reality of a different nature ; that stagnating liquor sanguinis is capable of undergoing, in its own proper substance, inflammatory changes ; or that the pus-corpuscle is capable of forming, in stagnating liquor sanguinis through some peculiar influence of non-inflammatory nature. Reason, collateral experience, and the general laws of pathology, point to the second of these propositions as the most probable of the three ; but it is wisest for the present, perhaps, to refrain from adopting any one of them.\n(c.) Epithelial fluid.\u2014Broken or perfect epithelial scales sometimes accumulate in very considerable quantities in certain serous fluids ; and the resulting mixture cannot with the naked eye be positively distinguished, either by colour, consistence, or odour, from pus. In the Fallopian tube (somewhat dilated) of an anasarcous woman, who died under our care at University College Hospital some time since, we found fluid of this kind, containing (as shown by the microscope, the only test in such cases,) not a single pus-corpuscle, but abundance of epithelium. We have seen the same kind of fluid in the pelvis of the kidney.\nThe microscopical distinctions of the unaltered red-corpuscle of the blood, and the pus-corpuscle, are so numerous and obvious that they need not be enumerated ; it is im-\npossible to confound the two objects. The red blood-corpuscles, however, when acted upon by various re-agents (serum, urine, pus, artificially added saline solutions, &c.) acquire a more or less accurate resemblance to those of pus ; they in truth increase somewhat in bulk, lose their regularity of outline, which becomes ragged, and alternately notched and studded with minute prominences, \u2014 appearances which have led to very remarkable errors. Nevertheless, the resemblance is far, even, from seemingly perfect ; the altered red-corpuscle is smaller than the other, and is not minutely granular on the surface : if there be doubt, however, in the case, acetic acid, by dissolving the body (if it be a red-corpuscle), or producing the changes already described (if it be one of pus), will settle the question.\nThe colourless corpuscle of the blood in its unaltered state is with difficulty distinguishable from the pus-corpuscle ; the two bodies have, by practised observers even, been confounded. It has the same minutely granulated aspect ; and acetic acid discloses, as in the pus-corpuscle, a nucleus in its interior. The colourless corpuscle is smaller than the other, however (the mean ratio of their sizes being as 22 to 27, nearly). The nucleus is either single, bipartite, or tripartite.\nThe process by which pus is formed \u2014 in other words, pyogenesis or suppuration \u2014 was long supposed to be one of disintegration and solution of the natural tissues. We need not devote space to the elaborate refutation of this rude conception : suffice it to say, that pus may be produced for years from mucous membranes, without even abrasion of their surfaces having occurred, and that the elementary textures (e. g. the cellular) may, at the outset of the suppurative process, be shown to have retained all their natural properties.\nWe might, on the score of its obvious fallacy, similarly pass by the notion that the corpuscles of pus are simple modifications of the red-corpuscles of the blood ; but as, even recently, symptoms of a return to this previously-exploded idea have appeared on the Continent, a few words on the subject seem called for. M. Gendrin (Hist. Anat. de VInflammation, fyc.) taught that in consequence of the stagnation of the red-corpuscles induced by inflammation, those bodies are first converted into pus-corpuscles in the interior of the capillary vessels, and, secondly, exude thence into the intercapiliary texture. The experiment upon which the first portion of this doctrine was based has been repeated by Dr. Wood*, Mr. Gulliver, and others ; and either no appearance at all of the alleged puriform matter discovered, or its characters proved to be those of softened fibrin. As respects the exudation of ready-formed pus-corpuscles, the theory manifestly involves an impossibility, as the structure of the walls of the capillary vessels is too close to permit the passage of bodies of such dimensions.\n* Op. Cit. p. 4.\ni 2","page":115},{"file":"p0116.txt","language":"en","ocr_en":"116\tPRODUCTS, ADVENTITIOUS.\nBesides, M. Gendrin has forgotten to explain why, if the pus-corpuscles escape from the vessels, the blood-corpuscles, of much smaller size, as they are, do not follow abundantly in their track. M. Donne* some time since revived the idea of conversion, believing that he had seen red-corpuscles changed into purulent in a mixture of pus and blood out of the body: he was deceived by the physicochemical changes already referred to, which pus, like various other fluids, effects in the blood-corpuscles.\nThe true doctrine of pyogenesis is a modification of that of \u201c secretion \u201d taught by Simpson (1722), de Haen (1756), Morgan (1763), Brugmans (1785), and John Hunter. The direct microscopical evidence, upon which it has been finally established, was originally and mainly supplied by Wood, Gueter-bock, and Henle. This evidence is to the effect that, as a general fact, the generation of the solid materials of pus takes place wholly outside the vessels in a hyaline blastema. In that blastema granules first appear ; subsequently, bodies of larger size form, either independently of the granules or around them, and, collecting in variable numbers, or remaining single, present the characters of, and actually constitute, the nucleus of the pus-corpuscle. The involucrum, or cell-wall, next forms ; and, at first clear and transparent, subsequently grows granular. One of the readiest plans of observing this series of changes, is by using the exudation-fluid from a blistered surface,\u2014but the same phenomena may be traced on wounded surfaces.\nThe elementary tissues of the body are not at first altered in any appreciable manner by the occurrence of suppuration among themf ; solution of their substance may at length be, and frequently is, more or less completely effected. This solution-process is of triple nature : it is physical, in that mere maceration aids in its production ; chemical, in that in certain unhealthy states of the system, solvent agents, &c.J are generated in suppuration; vital, in that the tissues themselves, in certain constitutional conditions, lose partially or completely their force of cohesion.\n\u00a7 4. MELANIC DEPOSIT.\nBlack colouring matter appears under various conditions as a morbid deposit. The only kind strictly belonging to the present head, is true melanic granule or cell-pigment, more or less closely similar to natural pigment.\nMelanic pigment is essentially composed of extremely minute granules, for the most part contained within cells. The cells are of various shapes, commonly rounded, however ; not commonly of caudate form, but often showing a tendency to prolongation in one particular direction. They very rarely contain a nucleus.\n* Arch, de M\u00e9d. Juin, 1836.\nf The first change discoverable .under the microscope seems to he loss of elasticity.\nJ Prussic acid, according to Dumas. (Comptes Rendus de l\u2019Institut, 1841.)\nThe cells are of blackish, brownish, bistre or yellowish tint, the colour evidently depend ing on the granules. And these granules are not confined to the cells, but are commonly found, in multitudes, free ; when excessively minute they are the subjects of molecular motion. In some instances cells are not to be discovered at all.\nLittle is positively known concerning the development of melanic pigment, \u2014 either of the mode, whether exogenous or endogenous, by which increase of cells takes place, \u2014 or of the relationship in which the cells and granules stand to each other; that is, whether the cells are formed around the granules, or the granules generated within the cells. But while it is certain that the cells are deficient in the attribute of permanency, and appear of secondary importance (seeing that the pigment character may exist in perfection independently of them through ,the granules alone), it seems very unlikely that they are truly vegetative. Melanic cells never exhibit any tendency even to cohere \u2014 much less to form the basis of a stroma.\nThe chemical composition of this substance is not known with accuracy. Analyses in numbers no doubt have been printed, but none of them are entitled to confidence, \u2014 either because they include the composition of associated substances, organic and inorganic, or because the black matter analyzed was not really composed of cell-pigment. It is probable, however, that the ultimate constituents are the same, and associated in, at least very closely, the same proportions, as of the pigment of the choroid coat. Some of the more important reactions of this substance, as set down many years ago by Henry, may be substantiated readily, and have frequently been confirmed by ourselves. A \u201c softened melanotic tumour \u201d was experimented on: 1. By filtering through paper, much of the colouring matter remained on the paper, and the colour of that which passed through was rendered much less intense ; 2. Boiling does not destroy the colour, not even when a little caustic potass has been added; 3. It is not changed by acids even when heated, except by strong nitric acid, which turns it yellow ; 4. A stream of chlorine, passed through the liquid, destroys the colour, and throws down light-coloured floc-culi * ; 5. A few grains of corrosive sublimate (nitrate of mercury and muriate of tin also, though more slowly,) precipitate the colouring matter and leave the supernatant fluid clear.\nBlack cell-pigment occurs under two chief conditions \u2014 unassociated, or associated with other materials. The former condition is excessively rare, and we have certainly never seen it in the human subject, \u2014 that is, we have never seen a fluid or solid accumulation of cell-pigment utterly unmingled with other fluids or solids, natural or adventitious : it ap-\n* Chlorine water (which we have used) does not actually destroy the colour, but diminishes its intensity greatly.","page":116},{"file":"p0117.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t117\nears, however, to occur thus in the horse, n the associated form it is of very common occurrence, exhibiting itself in the form of points, spots, layers, or masses, in the substance of natural textures or of adventitious products. In the latter condition it has more particularly excited attention, and been described under the titles of \u201c melanosis,\u201d \u201cmelanotic tumour,\u201d \u201cmelanoma,\u201d &c. A full consideration of the modes of connection of cell-pigment with tumours will be found under the head of \u201c Melanoma\u201d in the section \u201c Growths.\u201d _\nThe substance we have just described being the only true black cell-figment, appears to be the only one legitimately falling under the present head ; but it is absolutely necessary (were it only for the purposes of diagnosis) that we should briefly consider certain other causes (most ably investigated by Dr. Carswell) of black discolouration. These causes are, (a.) Alteration of the colouring matter of the blood ; (b.) Introduction of black-coloured substances from without.\n(a.) Alteration of hcematosine.\u2014 Stagnation and extravasation, and the action of certain chemical agents, are followed by this alteration.\nStagnation produces its effect on the colour of the blood most distinctly in the capillary vessels, is more common in old than in young persons, and attends diseases of the heart and great vessels interfering with the circulation. Chronic inflammation is the most common immediate cause of the stagnation ; the intestinal canal and the lung the most common seats of the altered colour. In the intestinal canal, it is difficult (except by ascertaining the absence or presence of acid) to separate the effects of chemical agency from those of mere stagnation.\nJExtravasated blood (occupying localities altogether removed from the influence of chemical action not originating in itself, as, for example, in the common cellular membrane,) sometimes undergoes remarkable change of colour, becoming of a pitch black hue. The blackish and slaty discolouration frequently seen in points or patches under the mucous coat of the pelvis of the kidney, and also on the surface of the cortical substance, is evidently produced by infiltrated and altered blood. In these cases no pigment-cells are to be discovered, an amorphous granular mass exhibits itself, not materially differing in physical characters (it is not, however, mixed with crystals and fragments of tissue,) from the colouring matter of gangrenous detritus.\nChemical action is a frequent cause of blackening of the blood. Blood poured into the stomach, and sometimes even if retained within its veins, is blackened by the gastric juice, either by direct contact or by imbibition. The effects of the acid secretion are precisely such as are producible by acids on blood removed from the body. The slaty discolouration of the anterior border of the liver, so common an appearance, is similarly explicable ; the blood in its capillary texture being\nacted upon by hydro-sulphuric acid gas transuding through the adjacent intestines.\n(b.) Introduction of black coloured substances from without. \u2014 The lung (with its appendages) is the only organ in which this source of discolouration has been established. Pearson * was the first to suggest, that inhaled carbonaceous matter was the true cause of the black lines and patches (following the course of the lymphatic vessels) often seen on the surface of the lungs, and of the well-known dark hue of the bronchial glands. That the colouring material was not of animal nature, he inferred from its being insoluble in nitric acid. Pearson\u2019s view seemed to derive support from the well-known dark appearance of the morning expectoration of persons who habitually sit up much at night; and from the observation of Laennec, that the peasant^, but little prone to vigil, rarely expectorate dark sputa.\nBut the most absolute collateral demon stration of Pearson\u2019s correctness, is derived from the history of a peculiar disease to which colliers are subject. The lungs of individuals affected with this disease become so thoroughly black ( Univ. Coll. Museum) as to resemble coal in colour ; and undergo gradual breaking up from irritative and ulcerative action.f Now the carbonaceous nature of this material, having been made matter of notoriety by the experiments of numerous persons, it appeared natural to conclude that it was composed of coal dust inhaled in a state of extreme division. This notion was indeed espoused by Dr. J. C. Gregory j, but proved to be erroneous by Professor Graham), who showed that the material carried into the lung was none other than the soot or lamp-black formed by the combustion of the oil which the colliers use, suspended from their heads, as they work, in mines where the safety-lamp is not used. The constant exposure to the smoke of gunpowder employed for blasting has the same effect, though in a less degree.\nIt remains for us to add, that we entertain no doubt of the black tint, present always more or less extensively in the lungs and bronchial glands of healthy persons (generally speaking, in the direct ratio of their ages), being in part due to inhaled sooty matter, but believe that it is likewise in part caused by alteration of the h\u00e6matin of blood stagnating in the capillary vessels. This opinion is, however, based on too small a number of micro-chemical examinations to lay claim to general admission.\nFinally, we may observe that the relationship of true melanic cell-pigment to the constituents of the blood, though made the subject of much dogmatical assertion, is altogether unknown.\n* Phil. Trans. 1813.\nf The precise anatomical characters of the disease it is, of course, beside our present purpose to enumerate.\ni Ed. Med. and Surg. Journal, No. 109.\n\u00a7 Ibid. Yol. 42.\ni 3","page":117},{"file":"p0118.txt","language":"en","ocr_en":"118\tPRODUCTS, ADVENTITIOUS.\n$ 5. DIPHTHERITIC DEPOSIT.\nThe inflammatory action giving rise to the deposits which we include under the title Diphtheritic (AupOepr1, a membrane), is certainly of special kind, though the intimate nature of its peculiarity is yet undiscovered. These deposits form on the tegumentary surfaces, mucous and cutaneous.\n(a.) White Thrush (Muguet of the French). \u2014 The matter of white thrush forms on the mucous membrane of the mouth, fauces, \u00e6so-phagus, and nasal passages, in patches of milky colour, cheesy consistence, variable size, and irregular form. Adhering closely to the mucous surface when first exuded, it gradually becomes more and more easily separable ; if artificially removed, the subjacent surface looks slightly hollowed and somewhat raw, but is not abraded.\nThe microscope exhibits molecules ; cells of oval, spherical, or elongated form, with or without nuclei ; epithelium cells, in more or less abundance ; and fibrils. These fibrils, almost transparent, of delicate and sharply-defined outline, of cylindrical form, generally uniform in thickness, but sometimes swollen irregularly, and occasionally bifurcated, are not affected by water, acetic or nitric acids, or alkalies, but dissolve in sul-phuric acid. Hence it appears obvious that this substance is in part entophytic ; but it is only secondarily so, \u2014 the rapid development of fungi depending on the constitutional state, or, perhaps, upon the chemical condition, of the local secretions. The smallest cells are probably sporules.\nThere is no structural difference between the matter existing in the white thrush of children, and that appearing on the mucous membrane of the mouth in adults towards the close of lingering chronic diseases, especially phthisis. But it has appeared to us from numerous observations, that it is less prone to become entophytic.\n(h.) We have examined with some care the white material of cheesy consistence which forms, in certain states of the constitution, on blistered surfaces, kept open by irritant ointments, and find no particular difference between it and the similar produce of mucous membrane. Entophytic formation occurs here.\nOrder II.\u2014Growths.\n\u00a7 1. Growths possess texture which differs in physical characters from all natural tissues, the arrangement of their septa and loculi being, among other things, distinctive of themselves. They differ, further, from natural structures, in a total deficiency of modelling faculty; they enlarge in all directions indifferently, careless, as it were, of the mechanical mischiefs their presence may inflict. They are composed of evanescent vegetating cells, incapable of propagation by artificial inoculation into the tissues of the individual producing them.\n$ 2. The existence of structure in the order Growths is apparent on superficial in-\nspection. And there is one unfailing characteristic of this structure, as displayed to the naked eye ; it consists of a stroma and an interstitial matter occupying its meshes. This, which is the most striking peculiarity on the surface of some tumours (enchondroma, colloid cancer), is much less evident in others (milt-like variety of encephaloid, many specimens of simple scirrhus) ; but in these latter it is clearly disclosed by slight maceration. And the want of a clear definition at first of stromal and interstitial parts depends, not on their non-existence, but on the more than ordinary similarity in physical characters of both. Generally speaking, in truth, there is a very obvious difference in this respect : the stroma of fully developed colloid has the aspect of cellulo-fibrous membrane, opaque and close ; its interstitial matter all the outward appearances of a jelly-like substance ; in enchondroma, the interstitial matter, resembling jelly of a different tint, is enclosed in a stroma, in many cases formed of laminae of bone. But, on the other hand, in some cases (as those referred to), there is no such obvious difference in the visible character of the two divisions, as they may be called, of the growth. In yet other cases, again, the outward characters of the stromal and interstitial parts differ in colour, transparency, density, tenacity, when roughly examined, and yet their intimate constitution is almost identical ; this is the case in fibrous tumours.\nIn the majority of Growths, the stromal substance encloses spaces inclining to the spherical form, a form most distinct in enchondroma, colloid cancer, and fibrous tumours ; only imperfectly seen in encephaloid ; almost completely absent in simple scirrhus and in erectile growths. The manner in which the sphericity of the loculi is produced will be considered further on.\nAnother element of Growths, which is visible to the naked eye, or may be rendered so by means of injection, is blood-vessel. In varying proportions all Growths possess vessels, which may be limited to their stromal substance, or permeate both stromal and intrastromal substances. These vessels are in part those of the textures invaded, by the new formation, in part adventitious products.\nLymphatic vessels and nerves are occa-sonally found within the area of a Growth ; but there is no evidence that they are ever of new formation.\n$ 3. The ultimate essential elements of tumours are granules, molecules, cells, free nuclei, and fibrils. With these elements are accidentally associated Precipitates, Deposits, Exudation-Products, and certain of the simpler Pseudo-Tissues.\n(a.) The elementary granule is spherical in shape, flattened or amorphous; averages in size tooof an inch ; and is seated in the interior of cells, or on the surface of fibres, or is free. The molecule is too minute for measurement.\n(A) Some portion of the substance of all","page":118},{"file":"p0119.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t119\nGrowths consist of hollow vesicular bodies or cells. The quantity of these cells varies extremely in different genera of Growths ; constituting the greater part of the mass of simple sarcoma and of enchondroma, abundant in colloid cancer, they are comparatively rare in scirrhus, and may be sought for in vain in the main substance of fibrous tumours.\nIn form the cells of Growths are spheroidal, as in sarcoma ; or ovoid, as in enchondroma ; and plump, or flattened, and discoid, in proportion to the abundance of their contents.\nIn respect of size they vary within wide limits, from the simple fact that it is the nature of some to go on increasing in bulk (for instance, the cells of colloid and of enchondroma), of others to retain persistently the dimensions originally acquired. This anatomical distinction is connected with a very important physiological difference in the mode of increase of Growths. We do not depart much from the truth in assigning 40V0 a\u00b0d of an inch as the extreme measurements of these bodies. Further, the cells of the same Growth vary in size, independently of endogenous enlargement.\nCells are either set beside each other, and cohere by their contiguous walls, or they remain free.\nThe thickness and transparency of the wall of cells vary; the wall may be collapsed and corrugated, or stretched and smooth ; the nucleus (when this exists) of the cell may be distinctly parietal or not.\nThe contents of cells are of four kinds : \u2014 fluid; granules; nuclei; young cells. Fluid, in more or less abundance, is constantly present in sound cells ; upon its amount mainly depends the plump or shrivelled aspect of these. Granules exist in abundance in the cells of sarcoma and of scirrhus. A free nucleus may be found sometimes in the cell of colloid cancer and of enchondroma. Young cells, themselves provided with a free or parietal nucleus, are seen in the interior of the large cells of the two Growths just named.\n(c.) The next element requiring consideration is the Nucleus. Nuclei are found in the great majority of Growths ; either free, in connection with cells (parietal or central), or attached to fibres. Free solid-looking corpuscles are found in the substance of scirrhus; these appear (whether generated free as they are seen, or originally connected with cells, and released by the disintegration of these) to be the germs of future cells. Of the parietal and central nucleus enough has already been said. The slightly granulated look of the fibres of Fibrous Growth depends on the permanent character of their nuclei, which appear set superficially in their substance. In whatever condition nuclei exist, they are distinguishable commonly by their comparative opacity; this is rendered more obvious by acetic acid, which increases the transparency of cell-walls, or by ioduretted solutions, in consequence of the tendency of nuclei to absorb coloured matters.\n(d.) Fibrils.\u2014Fibrillar substance occurs in Growths in many varieties of form and degrees of abundance.\nPeculiar fibres, of excessive transparency and delicacy, constitute the chief mass of the \u201cfasciculate\u201d variety of cancer. \u201c It is impossible,\u201d as we have elsewhere said, \u201c to look at these fibrils without being struck with their similarity to those of the buffy coat of the blood, or without conceiving the idea that blastema has been produced in connection with extravasated blood.\u201d\nFibres, differing but little from those of natural fibrous tissue, form the staple element of fibrous Growths, and are abundant in scirrhus.\nAn appearance of fibrous structure is produced in some Growths by linear juxtaposition of fusiform or straight caudate cells. These corpuscles have the aspect of spherical cells with two opposite points of their periphery prolonged into very minute tapering fibrils. (See fig. 93, p. 127.) Usually single, the fibril is sometimes bifid. The cell is obscurely nucleated, and frequently granulated; excessively abundant in sarcoma and cysto-sarcoma, appearing occasionally in hoematoma, cystoma, angeiectoma, melanoma, and carcinoma, they cannot be discovered in fibroma. Their presence signifies that of blastema of simple plastic character; and there is no certain evidence that the proper cell of cancer (in which formation they were at one time supposed to be of peculiar significance) is capable of assuming the perfectly fusiform shape. Our opinion on this point has of late grown much more decided. A shapelessly caudate cell, with irregularly curved fibrils, or lateral superadded fibril, is more closely allied to cancer, and will be described with that product.\nThe accidental and non-essential elements of Growths belong to the other divisions of Adventitious Product. From the class Precipitates may be found saline matter, amorphous or crystalline, in minute quantity, or so abundant as to convert (in the instance of fibroma) portions of a Growth into true concretions. Fat occurs in the various forms mentioned in a previous page ; rare in some genera, as fibroma and enchondroma; it abounds in carcinoma. From the order Deposits appear melanic matter and pus ; the latter an element generated by inflammation in Growths as in natural textures. Growths, too, of one kind may (as entozoa of one species grow in the bodies of another) find a nidus for development in Growths of a different kind ; cancer may thus appear within the area of an erectile tumour.\nExudation-Products exhibit themselves in the form of compound-granule corpuscles and induration-matter ; while of Pseudo-tissues, there occur epithelium, cartilage, cellular, serous, fibrous, elastic, osseous, cutaneous, pilous, and dental tissues; the last three limited to Cystoma.\nThe elementary cells of Growths may either lie in juxtaposition, or interspaces, filled with so-called intercell substance, may\ni 4","page":119},{"file":"p0120.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n120\nexist between them. This substance may be fluid or solid. Fluid intercell substance is nothing more than non-solidified blastema; the solid variety is amorphous, or composed of fibrous pseudo-tissue.\n\u00ff 4. The Physiology of Growths comprises the phenomena of their origin, enlargement, decay, elimination, cicatrization and local reproduction, \u2014 phenomena which, it appears to us, can, only by misapprehension of their true relations, be included under the head of the Pathology of these Formations.\nAll that is known actually, or surmised upon fair grounds, concerning the origin of Growths, has already been stated in our general remarks on Blastemal Formations.\nThe enlargement of Growths is effected by the reception and evolution of nutritious matter. Growths receive this matter from vessels ; these vessels either permeate the mass generally, supply portions only of its substance, or merely reach a greater or less extent of its surface. In the first case, the growth is said to enlarge by intussusception ; in the third, by pure imbibition ; in the second, by both means. These distinctions are less important than they on first view seem ; the perfect nutrition of the extra-vascular natural tissues proves, as a general fact, the vigour and efficacy of the imbibition-process ; and in truth imbibition is at play in all nutritions, for the nutrient elements of vascular tissues must be imbibed through the coats of their vessels, and (it may be) in addition (as in the instance of the endosteal lining of the canals of Flavers, and the subjacent osseous substance) through a stratum of cells. Enlargement by intussusception differs therefore from that by imbibition, in degree rather than in kind. In whichever way conveyed to the seat of Growth-formation, the nutrient material, at first fluid, is evolved and appropriated by continuous cell-generation. Now this cell-generation may be effected on an endogenous or an exogenous plan. When the plan is endogenous, the germs of young cells are contained and evolved within elder ones ; these secondary cells are endowed with a similar procreative faculty ; the tertiary series are in like manner fecund, and so on. Here a single cell may be regarded as the potential embryo of an entire growth. When, on the other hand, the plan is exogenous, the germs of new cells are not found within, but lie, and are evolved, outside old ones.\nWhere endogenous evolution prevails, and a cell is, potentially considered, a tumour in futuro, the perpetual production of similar cells is easily intelligible ; the offspring that follows is as the parent that went before. But in exogenous Growths the continuous germination of infinite series of like cells is not readily conceived. It may be surmised (and the surmise amounts rather to a modified expression of the fact than an explanation), that when a series of cells has sprung into being, this series acts on the evolution of succeeding ones, as a natural vascularized\nsurface is known to do on the generation of epithelium cells ; the formed series so influences newly-exuded blastema (of which it constantly excites the accession), that this shall produce a new series of cells similar to itself. But, however the perpetuation of like cells be understood, be it remembered that the thing itself has its limits ; for, as we have just seen, deposits may appear in Growths, pseudo-tissues are among their frequent constituents, and a growth of one kind may establish itself a nidus within the area of another generically dissimilar.\nElder cells thus seem (within certain limits) to cause the increase, and regulate the qualities, of younger ones. Younger cells are, on the other hand, more or less active agents in effecting the destruction of the elder ones : less so in endogenous Growths, where the elder may increase materially in size (as their contained brood multiplies), and acquire thickened walls ; more so in exogenous Growths, where such enlargement of cells is not witnessed, and where the production of young is coeval with the disintegration of old ones.\nSuch are the modes of production and increase of cells, considered in their general relations to themselves and to the mass they form. We must now view cells as individual existences, and inquire into the process by which they are each developed ; and our knowledge of this process is as yet limited and unsettled. The spherical cell appears to be produced on three distinct plans, (a.) Granular matter, precipitated from the fluid blastema, accumulates sufficiently to form a minute solid body (cytoblast or nucleus), from and around which the cell-wall forms. (b.) The cell is a molecular hollow body from the first, and, as it grows, produces within itself, or in its wall, a secondary body, the nucleus, \u2014 the cytoblast of a future cell, (c.) The cell is, from the first moment of its existence, complete in all its parts, consisting of a cell-wall, a nucleus, and fluid contents ; its development consists in the progressive and justly-proportioned increase of all these elements. The caudate cell is held to arise (as already hinted) from the prolongation of opposite points of the wall of a spherical cell ; but there is no proof that cells may not exhibit this shape from the first moment they are possessed of form at all. Lastly, the elementary fibre is held to be formed in three different modes, (\u00ab.) A spherical cell having undergone elongation so as to become caudate, loses by still increased elongation and flattening, the characters of a hollow cell altogether ; a nucleated fibre is the result, (\u00e8.) Elongation and linear juxtaposition of nuclei effect the formation of fibre. (c.) Or, it is held, fibres form as such from the first moment shape is assumed ; no cell, or nucleus-stage having pre-existed. All these points are yet sub judice.\nThe plan of enlargement and mode of arrangement of the ultimate elements of","page":120},{"file":"p0121.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nGrowths seem to exercise a very distinct influence on the structural character of the mass as visible to the naked eye. The locular aspect of their divided surfaces, for instance, we fully believe to be dependent on such influence. In the case of Growths enlarging on the endogenous plan, it is obvious that the juxtaposition of successive round cells within a containing or parent cell must cause this to retain its spherical outline, until it has enlarged sufficiently to become visible with the naked eye ; and further, that if several of these enlarged ceils be placed round a common centre and beside each other, the general form of the area they cover must be spherical. And so we find that it is precisely in enchon-droma and in colloid cancer, distinctly endogenous formations, that sphericity is most decided. The thickening and fibrous deposition, which take place both in the walls of enlarged cells and in the intercell substance, contribute further to the deceptive appearance of encysted structure. In masses which enlarge on the exogenous plan, the spherical character in the loculi is much less apparent. In scirrhus, and in many specimens of ence-phaloid, it is not to be clearly descried ; the predominance of straightly-fibrous arrangement of the stroma, produced by the presence of real fibrous tissue, of fusiform corpuscles, &c., accounts for this. But even in Growths of this class, the original rounded form of the elementary constituents tends to impress upon their larger divisions, as these do upon the entire mass, the spherical shape. Accidental circumstances, of course, are liable to affect this ; but the internal locular arrangement of fibrous tumours shows that those circumstances may be only partially effectual.\nThe locular character (under the title of \u201c encysted \u201d) has been put forward as an evidence of \u201cmalignity\u201d on the part of the structure exhibiting it. Experience proves the notion to be untenable. Sphericity of the loculi is most obvious in enchondroma, one of the most intrinsically innocent Growths known ; such sphericity is, on the other hand, totally, or almost totally, wanting in scirrhus and many specimens of encephaloid. Again, the least deleterious form of cancer \u2014 colloid, exhibits it in an especial manner; and, though modified, it is evident in those peculiarly benignant structures (considered in their essence) fibrous tumours.\nThe decay of Growths is preceded by softening of their substance ; this softening, indeed, by its increase actually constitutes their decay. The change is effected by infiltration of serosity, interstitial haemorrhage, by saturation with inflammation-products and by gangrene, either of inflammatory or simply mechanical origin. Or, there is an important class of cases, in which the softening of Growths seems analagous to that undergone by stagnating fibrin, and probably depends on chemical decomposition.\nThe removal of Growths (fibrous, cancerous, and others,) is sometimes effected by a spontaneous process, commonly comprising at-\n121\ntenuation and rupture, or ulceration of the investing natural tissues, and gradual liquefaction of the morbid matter, which is poured through the opening ; or, in less common cases, consisting of sphacelus, whereby the mass, in whole or in part, is separated from its connections.\nCicatrisation of the ulcerated surfaces of Growths is occasionally witnessed. We have ourselves seen this change occur on the proper surface of formations possessing all the characters of scirrhus.\nGrowths of all descriptions are liable, when removed spontaneously or by art, to be reproduced in the spot they previously occupied, if the removal have not been absolutely complete. The particles left behind act as attractive forces for new blastema convertible into cells, similar to those of which themselves are composed. This mode of reproduction (as it is erroneously called, for it is nothing more than enlargement, facilitated by removal of pressure of pre-existing substance) occurs with Growths of all kinds, cancerous, sarcomatous, fibrous, fatty, enchondromatous, erectile, &c. But it would appear that in some cases of surgical removal, when the whole mass has, as is presumed, been extirpated, a new growth vegetates in its place. The difference of the cases is often rather apparent than real : we have distinctly found the ger-mina of cancer in tissue, reputed healthy, surrounding a cancerous mass ; and it is manifest that such germina, though invisible to the naked eye, may, quite as readily as a fragment of diseased tissue of even considerable size, act as the efficient agents of new development. When, independently of this mode of generation, the disease returns in the seat of its former growth, the occurrence must depend upon the continuance of that depraved state of the blood which is fitted to supply the necessary blastema, and likewise, possibly, upon some peculiar state of vessels of the part favouring its exudation here rather than elsewhere.\nIn other cases, hardly has a growth been removed from one place, when a mass of the same kind appears in some distant and apparently unconnected part of the body : this occurrence, which is especially observed in the case of cancer, is termed its \u201c distant reproduction,\u201d and is explicable in two ways. The newly discovered growth may have existed previously to the extirpation of the old one, and having simply acquired additional activity, so become obvious, after that extirpation. Or the new growth may really have first appeared subsequently to the removal of the old (this we believe to be rare) : in this case the simple explanation is that the vitiated state of the blood, proper for the supply of the necessary blastema, continues ; and this blastema is poured out in some other part of the frame, the original tumour no longer existing to attract its deposition within or around itself.\n$ 5. The chemical study of Growths is yet in its infancy. Midler\u2019s division into three chemical classes, the albuminous, the gelatinous, and","page":121},{"file":"p0122.txt","language":"en","ocr_en":"122\nPRODUCTS, ADVENTITIOUS.\nthe fatty (rational enough, chemically considered,) fails pathologically. Growths of very opposite tendencies and attributes are to be found in the same chemical class ; thus the most deleterious forms of cancer are albuminous, while sarcoma (per se most innocent) is the same in its chemical basis.\n(a.) In the albuminous growth the other forms of protein are frequently present as essential ingredients ; the term growth of protein-basis appears therefore more strictly applicable. A matter said to be allied to ptyalin has been found in this class. Continued ebullition scarcely furnishes a trace of gelatin ; and when some such trace does appear, is probably derived from natural gelatinous textures accidentally connected with the morbid mass.\n(6.) Growths of the gelatinous class are almost completely reduced to jelly by boiling. The gelatin yielded is either of the common species, as in fibroma, or of the variety known as chondrin, and first detected by M\u00fcller in enchondroma.\n(c.) In the fatty class, the fatty matter is chemically the same as that of ordinary adipose tissue (e. g. in lipoma) ; or it is more or less closely allied to cholesterin (e. g. in cholesteatoma).\nThe fatty particles which exist in almost all Growths, even of the albuminous kind, and which do not form the essential part of the mass, are not contained in cells, as in true fatty Growths, but exist in the various forms enumerated in a former passage.\nCarbonates, hydrochlorates, and phosphates of the alkalies and earths are the inorganic salts most commonly and largely associated with the animal constituents of growth.\n\u00a7 6. The Pathology of Growths embraces the subjects, first, of the morbid changes arising in, or in immediate connection with, those formations ; and, secondly, of the various conditions of the system which precede, accompany, and follow their evolution. Then-pathology may, in other words, be regarded as local and general.\n{a.) Local. \u2014 Under the head of physiology we have considered briefly the various changes arising in Growths, as essential phenomena of their complete development ; and which, however they may be regarded as morbid in respect of the system generally, are, on the part of the adventitious mass in w'hich they take place, evidences of natural progress. But there are numerous changes occasionally occurring in Growths, that are actually morbid in essence in relation to the substance of the new product itself ; and others of a similar character which are produced in the surrounding tissues. These two classes of changes (which can only be glanced at here) constitute the materials of the Local Pathology of Growths.\n1. The changes observable in the substance of Growths, and which signify a departure from the regular process of evolution, are : \u2014 congestion ; infiltration with blood or with serosity ; h\u00e6morrhage, and in consequence of\nthese states, various forms of discolouration ; inflammation ; mortification ; and the deposition within or upon them of some adventitious material foreign to their nature. In fact, the chief morbid changes occurring in the natural structures may arise in these formations.\n2. The effects produced by Growths on surrounding tissues are mechanical and vital.\nThe mechanical variety comprises detrusion and various other displacements; condensation ; discolouration ; infiltration ; blocking up of cavities ; interference with the motion of fluids, &c.\nThe detrusion produced by Growths may be simple, expansive, or causing peduncula-tion, a peculiarity observed when certain Growths, endued with little or no tendency to infiltrate the parts around, originate between a mucous or serous surface, and a hard, resisting tissue. And this for obvious reasons; with the progress of their enlargement the distention they induce does not equably affect all surrounding parts (because the resistance of these is unequal), but acts especially upon the least resisting structures. As they enlarge, they carry these structures before them, until themselves eventually protrude sufficiently from their precise seat of origin to leave a sort of process of the membrane they push before them, acting as a stalk of attachment to the place of their original connection.\nA growth thus pedunculated is practically known as a Polypus, a term extremely injudicious, as it leads the observer to neglect the important matter of the nature of the tumour, and to regard a mere accident of shape as an essential feature.\nThe vital effects are rarefaction ; condensation ; atrophy ; hypertrophy ; inflammation, with its results \u2014 adhesion, softening, induration, ulceration, mortification, perforation, effusion of blood, enlargement of vessels, &c.; and, most important of all, infiltration of the surrounding tissues with matter similar to that composing the new growth. This last effect occurs (as we believe) in connection with no growth except cancer, and constituting one of the most evident pathological and nosological distinctions between cancerous and other allied formations, will be presently examined.\n\u00ff 7. The nature of this work will not admit of any extended observations on the general Pathology of Growths, but some prominent facts can scarcely be passed over in silence.\nThe conditions of localization of Growths are curious, and for the most part inexplicable. The following propositions may be laid down concerning them : \u2014\n(a.) The tendency to become the seat of Growths, as a class, varies greatly in the different tissues and organs. Thus, while cellular tissue is their peculiarly favourite site, fibrous texture but rarely affords them a nidus. Again, the mamma, the ovary, the uterus, are frequent, the lungs and brain much less common, sufferers.\n(\u00e0.) The tendency to become the seat of","page":122},{"file":"p0123.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nGrowths, as a class, varies in the different parts of organs. Thus the pyloric end of the stomach suffers more frequently than the rest of the organ ; the epididymis than the body of the testis.\n(e.) Certain organs, and certain parts of organs, have an excess of tendency to the formation of certain special Growths. Thus the uterus, the mamma, the stomach, the liver, are peculiarly prone to cancerous, as distinguished from other forms of growth ; the bones are the chosen seat of enchondroma. And, again, cancer does not form indifferently in all parts of the uterus, but tends especially to invade its neck ; while fibrous tumours affect a preference for the body of the organ. The large intestine is a tolerably common seat of cancer ; the small is very rarely implicated.\n(d.) Growths of different kinds exhibit different degrees of compatibility as co-existences in the same body. Some Growths, as Cystoma and Carcinoma, are sufficiently prone to appear in the same individual; others, as Fibroma and Carcinoma, are rare co-existences; none are actually incompatible, either as unconnected co-existences, or as developments in each other.*\nSex influences the site of Growths. The renal organs of the male suffer more frequently than those of the female ; the converse is true of the genital organs. In like manner, age has its influence. But on the whole, the causes of these peculiarities of seat are unfathomed.\nA Growth having once been developed, may pursue an anatomical (or better, topographical) course, of three different kinds. First, it may remain solitary and alone till the death of the individual in whom it exists, no other organ or tissue than that originally affected becoming involved by similar disease. This is frequently observed in the case of enchondroma and of cystoid tumours, occasionally of fibrous, and even of cancerous Growths.\nOr, secondly, a morbid mass originates in some particular site, whence it seems to spread as from a centre to a multitude of parts ; the latter are said to be the subject of secondary Growths. The mechanism of this propagation differs according as parts adjacent to or distant from the primary formation are the consecutive sufferers. (1.) When circumjacent tissues become the seat of secondary development, this is either the result ; \u2014 first, of pro-\n* It is true we have never ourselves seen cancer within the substance of a fibrous tumour ; but there is no \u00e0 priori motive for disbelieving the possibility of such localization, and competent persons affirm they have seen examples of it. Although tubercle is not, properly speaking, a growth, it may be well to observe here (as we first showed eight years ago), that this product and cancer rarely co-exist. Among 104 cases of death from cancer, there were but seven in which the anatomical character of phthisis was present. The age at which the two diseases are most prevalent will, to some extent, but not wholly, explain this result. (See Nat. and Treatment of Cancer, p. 185.) On the other hand, the diseases by no means absolutely exclude each other ; cancer and tubercle may form in the same organ.\n123\ngressive and direct infiltration of those tissues by the morbid matter ; or next, of infiltration spreading to those tissues through the medium of the proceeds of common inflammation (induration-matter) previously deposited among them, in some instances effecting adhesions between parts not actually adherent to each other in the natural state ; or, lastly, possibly of infiltration arising in some unexplained way, through the influence of a part simply placed in juxtaposition, and not continuous (either naturally or accidentally) with the tissues primarily affected. These modes of secondary implication are exemplified by cancer alone. (2.) The formation of secondary Growths in distant organs, where an effect of pre-existing disease elsewhere, seems only intelligible as a result of transmission by the lymphatic or vascular systems. Cancerous, and perhaps fibrous tumours, give rise through both these routes, to secondary development. As respects the lymphatic glands in communication with a cancerous mass, they may themselves become cancerous, while the vessels leading to them are either filled with morbid matter of the same kind, or perfectly free from all anatomical change. Now when the tubes are themselves loaded with cancerous substance, and are, for example, traceable so loaded even to the thoracic duct (A. Cooper ; Hourmann), without any evidence existing of the matter being a product of their own tissue, the implication of the lymphatic system, is evidently the result of absorption. But when (as is more commonly the fact) the cancerous state of the glands is unassociated with similar contamination of the connecting tubes, it is not thus so plainly and satisfactorily explicable. Still it is probable that in the majority of cases the principle is even here the same ; but that the mode in which stagnation of absorbed particles takes place differs. In other instances it is possible that cancerous development in the glands ma}r be effected as in an independent and original centre of production, and not through a process of absorption or other direct mode cf influence of pre-existing Growths. These notions are put hypothetically ; but they appear to me more likely to be well founded than those usually tendered. Nevertheless if contamination be admitted to arise as a result of absorption in some instances, the inference appears necessary, that it shall occur in all cases ; inasmuch as a process of nutrition, accomplished in the usual way, is constantly going forward in morbid Growths. Now, as matter of fact, such contamination does not always ensue, and, above all, does not commence from the earliest period of evolution of the previous growth. Here seems to lie a serious objection to the doctrine of lymphatic absorption. But the absorption is only thus shown to be of a kind which we may, for convenience sake, call unproductive ; and which may be assimilated to that taking place from abscesses, in cases where no pus, with its sum of natural properties, finds its way into the circulation. That the pus-corpuscles undergo, in such cases, dis-","page":123},{"file":"p0124.txt","language":"en","ocr_en":"121\nPRODUCTS, ADVENTITIOUS.\nintegration and alteration, is matter of physical demonstration \u2014 changes which divest them apparently of their pathological properties. On analogy, which seems in nowise strained, we may then admit that disintegration of the elementary cells of the morbid Growth is the cause of the occasionally unproductive character of cancerous absorption.* When, on the other hand, secondary Growths form in localities free from direct lymphatic communication with the seat of the primary formation, there can be no doubt (although the productive elements have not yet been found in transitu with the circulating blood) that the venous system acts as the agent of translation of such elements from the one to the other site. In the instance of cancer the following arguments may be adduced in favour of this notion, a. \u201c Cancerous matter exists in a multitude of cases in the veins of the diseased part ; now this is obviously a most favourable circumstance for its circulation with the returning blood. 0. The rapidity of the successive development of the disease in different organs, sometimes observed, seems only producible by the agency of a fluid which, like the blood, pervades them all. 7. The liver and lung, the two organs in which foreign bodies introduced into the circulation are almost invariably observed to stagnate, are by far the most frequent seats of the secondary development of carcinoma. 5. The parenchymatous viscera and the bones, the precise structures most frequently affected with secondary abscess, are those peculiarly liable to secondary cancer, e. In respect of both morbid products, the liver and lungs stand at the head of the list for frequency of implication, f. Secondary abscesses affect a special preference for the peripheric strata of the viscera ; so likewise do secondary cancers. In the instance of the lung, I believe this readily explicable, by the fact that the majority of the ultimate ramifications of the pulmonary artery reach the periphery of the organ before becoming continuous with the capillaries, wherein stagnation must occur. 77. Double organs are very rarely the simultaneous seats of primary abscess ; in cases of secondary abscess both invariably suffer : the same propositions hold good of cancer. \u00d4-. Secondary cancer in the liver and lung occupies the same elementary seat (the lobules) as the pus of\n* Absorption of cancerous matter artificially induced, would \u00e0 priori appear likely to prove of the unproductive kind, as disintegration of the primary particles of the growth must, in all probability, form a stage of the absorptive process. The question is rendered one of practical interest by the prospect held out of removing these tumours by the ingenious system of pressure invented by Dr. Arnott. It is clear, in truth, that if that system only lead to the translation, from one part of the frame to another, of elements endowed with the faculty of unlimited germination, the benefit obtainable from it is more apparent than real. Whereas if, while that system causes their entry into the circulating fluids, it deprives their elements of all productive power, and leaves them in a condition fit for excretion as effete particles, a perfect cure of the disease is effected by the removal of the tumour.\nsecondary abscesses.\u201d* Some apparent objections to the doctrine here upheld are examined and (as we believe) refuted in the same place.\nOr, thirdly, in certain cases where numerous parts are found to be the seats of tumours of the same species, it is more than probable that the development of these tumours has been simultaneous, and each mass been evolved independently of its fellows. There can be no doubt, for instance, that internal cancer is frequently described as secondary to external cancer (especially when the latter has been removed with the knife, and the former has not manifested its existence by symptoms until after the operation), where no proof of the two Growths not having originated at the same time can possibly be adduced. The same is true of Fibrous Growths.\nThe inoculability of Growths has not been maintained except in the instance of cancer, and, even in respect of this product, upon very imperfect evidence. Experimental results may be cited against (Dupuytren), and in favour of (Langenbeck), the transmissibility of the disease by inoculation ; while, on the other hand, we learn from M. Gluge that his attempts generally failed utterly, and in rare cases appeared to succeed. Theoretical considerations, repudiating, as they do, the idea of the constant inoculability of cancer-elements in organisms of all varieties of morbid aptitude, nevertheless do not wholly oppose the notion, that where constitutional predisposition to cancer exists in an animal, the germinal element of that product, introduced into its blood, may prove prolific. Unless this constitutional state exist, \u201c even the actual elements of cancer only manifest themselves as simply irritative agents, the perfection of the seed is not enough to secure the de~ velopment of the plant; the soil, in which it is sown, must be capable of feeding it.\u201d Perhaps these views furnish a clue to the contradictory statements of experimentalists.\n$ 8. Clinical observers of disease have long been aware that certain Growths are of evil, others of innocent, tendency ; that they are \u201c malignant\u201d and \u201cbenignant.\u201d Morbid anatomists have sought to connect definite and invariable structural characters with the possession of one or the other tendency ; and their search has been vain. Micrologists are divided on this question ; some affirm that \u201cmalignancy\u201d depends on the presence of a special cell ; others deny the distinctiveness of microscopical elements.\nWe, for our own parts, believe that the qualities of a growth cannot be determined by the characters of its cell. We have known Growths, which had destroyed life with the cachexia of cancerous disease, and clearly exhibited the local progress and naked-eye characteristics of encephaloid; Growths which, nevertheless, were composed of non-nucle-ated cells undistinguishable from those of common exudation-matter. Nor do we be-\n* Nat. and Treatment of Cancer, p. 106.","page":124},{"file":"p0125.txt","language":"en","ocr_en":"125\nPRODUCTS, ADVENTITIOUS.\nlieve that any mode of association of cell and fibril (at least any mode now known and understood) can be considered distinctive of carcinoma. On the other hand, we believe that Growths of evil tendency have a manner peculiar to themselves (ascertainable by naked-eye observation) of accumulating in the tissues. We refer to accumulation by infiltration. The nature of infiltration is easily explained. The elementary molecules of the morbid matter, instead of accumulating round a central point equally in all directions, and pushing aside the tissues amid which they are deposited, spread between the primary elements of those tissues on every side. In proportion as this extension of the morbid matter is accomplished, interference with the healthy process of nutrition takes place. The effete particles of the natural tissues cease to be replaced by similar ones ; and an appearance of conversion (\u201c transformation \u201d or \u201c degeneration \u201d) of a natural into a morbid structure is worked out. But if the nature of the phenomenon be simple, its cause is obscure. Why it should occur (as we conceive it does) in the instance of cancer alone, and why peculiarities so important as those of cancer, in respect of general influence on the system, should appear to hang upon the existence of a local pathological attribute, in nowise remarkable, strictly considered per se, is a difficulty which facts are wanting to explain away. Speculatively, as we have formerly said, \u201c we must look elsewhere for an explanation of the evils practically connected with infiltration, than to the mere physical phenomenon itself, \u2014 in a word, we must seek elsewhere some condition of which the process is but a consequence or involution. But the natural place to look for this condition is in the tissues themselves, which undergo infiltration ; and in these \u2014 in some special morbid change within them \u2014 must reside the source and origin of the process. And this view is confirmed by the fact, that there is nothing in the mode of vegetation of cancer itself to explain why it alone, among vegetating new formations, should possess the pou'er of infiltrating the natural tissues.\u201d\nWe are aware that the property of infiltration has been ascribed to other Growths besides cancer ; that fibrous tumours have, for instance, been said to affect circumjacent tissues in this manner. But we are persuaded, from close examination of such alleged cases, that infiltration with common plastic matter (the produce of inflammation arising from irritating pressure on the part of the tumour) has been mistaken for infiltration with substance identical with that of the fibrous growth ; and that the distinction is nosologieally sound.\nOn the grounds just set forth, we propose to divide the order Growths into two suborders\u2014 the Non-Infiltrating and the Infiltrating.\nSUB-ORDER 1.\u2014NON-INFILTRATING GROWTHS.\nThe genera in this sub-order may be arranged according to chemical composition \u2014 the protein compounds, fat and gelatin, being severally the predominant element.\nOf Protein-Basis.\n\u00a7 1. H\u00c6MATOMA.\nBlood effused into the tissues may be either (a) absorbed wholly or partially, or (b) not absorbed.\n(\u0430)\t1. If the blood be absorbed wholly, no vestige of the haemorrhage may ultimately be traceable, even in the condition of the tissue amid which it occurred ; or (as is more common) even after the total removal of the blood-elements, some slight puckering, changed density, or changed position of the proper texture of the organ (of the brain, for instance) reveals the fact that haemorrhage has occurred. In either case, blood has escaped from the vessels without leaving even the potential elements of a growth behind it. 2. Partial absorption acts commonly upon the watery and colouring matters of the blood, the fibrin alone remaining : this fibrin (fibrinous haematoma, from a'1/j.a.Tujia, blood-tumour), may form a single mass, as is usual in the parenchymata, or several fragmentary parcels, as happens generally in the serous cavities. Partial absorption, in a class of rarer cases, acts first upon the fibrin ; the effused blood becomes more thin and aqueous, and sometimes (spreading by infiltration and endosmosis amid the surrounding textures) is thence eventually absorbed : here no residue, referrible to the present head, remains behind.\n(\u0431)\tWhen not absorbed, blood either (1) excites inflammation and its consequences ; or (2) remains stationary in a fluid condition; or (3) assumes the characters of dark grumous semi-coagula ; or (4) undergoing inspissation from deprivation of its watery parts, a firm co-agulum, growing daily more solid, remains behind : in this last instance we have a coloured haematoma.\nA haematoma is then a fibrinous mass, coloured or not, arising from haemorrhage.\nBefore us (Univ. Coll. Mus.) lies a colourless haematoma of the spinal meninges in the cervical region, the result of a blow. Its size is that of a walnut ; it is of pale straw-colour, homogeneous on superficial view, but finely granular when closely inspected. Haematoma may, however, be coarsely loculated ; the walls of the loculi being solid, the contents more or less fluid, or gelatiniform-looking. Such tumours (while unchanged in characters) exhibit microscopically the qualities of fibrin, \u2014 fibrils gelatinizing with acetic acid,\u2014 amorphous fragments, granules, and molecules. Their colour varies ; it may be of deep yellow, somewhat buff, tint,\u2014 and commonlj' is so, in the spleen and kidney, for instance. Their chemical reactions are those of fibrin.\nThe surface of a haematoma is smooth ; a coating of epithelial structure, rapidly form-","page":125},{"file":"p0126.txt","language":"en","ocr_en":"126\nPRODUCTS, ADVENTITIOUS.\ning, gives it this character. A h\u00e6matoma is rarely encysted; for though nothing is more common than the formation of a cyst round effused blood (apoplectic cyst) as a general fact, yet this process is rarely witnessed, where the progress of absorption has been of the kind to produce a h\u00e6matoma.\nH\u00e6matomata may probably form wherever blood, thrown out from the vessels, is retained. Thus (1) they are seen in the serous cavities,\u2014as the peritonaeum and pleura, where they have more than once been found in the stages of transition ; and in synovial cavities, where, as John Hunter long since maintained, they frequently form the so-called \u201c loose cartilages\u201d of joints. (2) Amid membranous structures,\u2014as for instance, under the choroid coat, where they have been frequently mistaken for carcinoma ; into the great cavity of the arachnoid (Univ. Coll. Mus.) \u2014 a not uncommon seat ; between the arachnoid and dura mater of the skull, where, we feel positive, they have occasionally been the origin of minute fibrous tumours ; under the mucous lining of the uterus, where a similar destiny sometimes awaits them ; under the periosteum, either when the blood has flown through the influence of external injury, or through the influence of causes, partly traumatic, partly spontaneous, as in that singular affection of new-born infants \u2014cephalh\u00e6matoma. \u2014 (3) In parenchymatous organs, as the brain, the spleen, the kidneys, the lung (in all of which we have repeatedly seen them), and more rarely in the mamma, where they have often, clinically, played the part of cancers.\u2014(4) In the cellulo-muscular structures of the limbs, as the result of contusions or spontaneous haemorrhage.\u2014(5) In the proper substance of certain new products, especially encephaloid cancers.\u2014(6) In cavities accidentally formed in the tissues, as in tuberculous cavities in the lung. (Univ. Coll. Mus.)\nVarious changes of deep interest may occur within the substance of a h\u00e6matoma. Unsupplied with vessels, as it commonly is, it cannot be the seat of interstitial haemorrhage ; but blood may nevertheless infiltrate its substance derived from the ruptured vessels of surrounding textures, \u2014 just as extra-vascular tissues may become infiltrated with exudation-matter produced by inflammation, not in them, but beside them .* Saline precipitation is a common occurrence ; such is often the origin of ossiform particles or masses in the brain ; of similar masses in advanced cephalh\u00e6matoma f ; and such (as elsewhere shown by us) is almost invariably the source of free calcareous and ossiform products in cancer: the changes concerned in the production of a phlebolith are one by one gone through. That melanic pigment may form in h\u00e6matomata appears extremely probable, from certain observations which we made several years ago on some specimens of melanic tumour ; full reference to these will be\n* A remarkable example of haemorrhage into a h\u00e6matoma of the brain lately occurred in our wards in University College Hospital.\nf See this word, Cyclopaedia of Surgery, vol. i.\nfound in the section on Melanoma. We have in a previous section spoken of the doubt still hanging over the question of the possible evolution of simple effused blood into Formations of definite structural characters. The question appears to be all but absolutely decided in the affirmative by a tumour now before us (Univ. Coll. Mus.), in the substance of which the transition from the characters of h\u00e6matoma to those of fibrous tumour, is perfectly traceable in point of colour, consistence, and textural arrangement. Bone-formation may take place from blood effused in localities where a tendency to such formation naturally exists, and where formative life is active. Thus, in the instance of sub-pericranial cephalh\u00e6matoma, the smooth gelatinous-looking membrane, which invests the blood, may become so perfectly ossified, that it has, in this state, been evidently mistaken by some observers for the outer table of the bone, and a figment, in the shape of interstitial or diploic cephalh\u00e6matoma, invented to meet the difficulty. Even in the centre of the fibrinous residue of this effused blood actual bone has sometimes been seen.\nConcerning the vascularization of blood in substance we have already given our opinion. H\u00e6matomata in the brain have been found distinctly vascularized in cases where there was no evidence that plastic lymph had been added to the extravasated blood ; and M. Louis\u2019 description, already referred to, of a vascularized coagulum in a tuberculous excavation of the lung is peculiarly satisfactory7.\nBlood retained in its proper canals may coagulate and undergo various changes. In the arteries, cellulo-fibrous evolution and calcification occur in stagnating blood without the intervention of an inflammatory process : in the veins we have seen vascularized coagula injected ; and the formation of phleboliths and arteroliths illustrates saline precipitation. Vascularized coagula in the heart have been described by Rigacci, Burns, Bouillaud, and others.\n\u00a7 2. SARCOMA.\nSimple sarcoma (aap\u00a3, flesh), or cellulo-vascular growth, presents itself as a mass of variable dimensions, \u2014 those of a hazel-nut and of a cocoa-nut are the extremes we have seen. Of oval or, less commonly, spherical outline, its surface may be even and tolerably smooth, or nodulated (U. C. Mus.). Sarcoma is particularly elastic ; varies much in consistence and density ; breaks sharply under the nail, in the direction of its fibres ; is rather crisp than tough, unless in the site of its cellulo-fibrous locular walls ; exhibits on section a tolerably smooth, glossy, semitransparent surface, such inequalities as exist depending upon the unequal elasticity of its containing and contained elements ; is free from greasiness, either to the look or feel ; is usually of pale yellowish or buff colour in the main, presenting here and there reddish or more rarely lilac-tinted spots, or striae, or","page":126},{"file":"p0127.txt","language":"en","ocr_en":"127\nPRODUCTS, ADVENTITIOUS.\n(it may be) a more or less uniform red hue ; and yields on pressure a small quantity of slightly glutinous, thin, yellowish, transparent fluid. The vessels of sarcoma may be pretty equally distributed through its substance, or set in a sort of patch-work.\nThese growths are essentially disposed to become encysted. Their cyst, vascular and cellular like themselves, may be fibrous in part, and is formed both of natural cellular tissue condensed, and of exudation-matter solidified. This secondary or pseudo-cyst adheres closely to their surface, and appears continuous with the cellular and thin, or fibrous, thick, and opaquely white, membranous septa of the growth.\nMolecular matter, granules, spherical, oval, and caudate cells, and fibres form the ultimate constituents of sarcoma. Its spherical cell seems to us identical with the common inflammatory exudation cell. (See Pseudo-Tissues.) The oval cell, of larger size (measuring .00073 of an English inch and upwards, according to some estimates by M\u00fcller), is provided with a dark, well defined, but small nucleus : such cells are sometimes enclosed within a mother cell-wall of proportional dimensions, and afford clear evidence of endogenous procreation. Slightly elongated at opposite ends, as they sometimes are, they eventually pass into the state of caudate or spindle-shaped cell {fig. 93). Such cau-\nFig. 93.\nCaudate cells from an albuminous sarcoma of the conjunctiva. (After M\u00fcller.)\ndate cells are either arranged in linear juxtaposition, as above ; or they are scattered loosely through the mass. They are not plainly nucleated, as a general rule ; but acetic acid brings out a parietal nucleus. They seem to pass by an easy transition into fibres ; and eventually these fibres acquire for the greater part the characters of those of cellular tissue, but occasionally of fibrous, and yet more rarely (we have seen this) of elastic texture. The molecular and granular matter of sarcoma is probably in part fatty ; but oil-globules are of rare occurrence.\nSarcoma is mainly composed of albumen ; but (especially when a cyst with thickened processes exists) will yield a small quantity of gelatin by boiling.\nThere are probably few sites in which sarcoma does not form. We have seen it in the cellular tissue under the lower jaw ; in the substance of both maxillae (whence it has frequently been removed with successful results); under the periosteum of the long bones, or (more rarely) in the actual substance of these ; in the mamma ; in the eye ; in connection with fibrous textures, as the dura mater, &c.\nHaemorrhage, calcification, and suppuration occur in sarcoma ; the latter with great rarity. We have never seen cancer within the area of a sarcoma.\nCondensation and detrusion of surrounding parts are mechanically caused by this growth ; it has no intrinsic tendency to affect those parts otherwise, though inflammatory changes may, from over distention, be induced among them.\n\u00a7 3. CYSTOMA.\nSee Pseudo-Tissues ; Serous.\n$ 4. ANGEIECTOMA.\nMasses of variable size composed of dilated and elongated vessels may be described under the name of angeiectoma (avyuov tuTuvwfi They are rare productions, and seem essentially produced by dilated hypertrophy of the small vessels, venous or arterial.\nA tumour of this kind has been figured by Dr. Carswell, (Fascic. Melanoma, pi. ii. fig. 2). It was sunk into the substance of the brain, but evidently in connection with the pia-mater. \u201c The bloodvessels of the pia-mater passed into it, and constituted by far the greater part of the tumour. They became tortuous in its substance; some of them, being nearly a line in diameter, were reflected backwards at their extremities in the form of irregular intertwined bundles, towards which two or three small arteries, coming from the pia-mater, were seen to distribute themselves.\u201d Lobstein (Anat. Path. t. i- p. 461) describes a similar mass formed of a venous plexus. In both these cases the veins contained, and were bathed in, melanic liquid. Dr. Warren (On Tumours) figures and describes a case of congenital tumour composed of greatly dilated and knotty veins seated in the neck.\nThere is a species of epulis which appears to be composed of dilated and hypertrophous arteries. Cruveilhier (Anat. Pathol, livrais. 33.) describes certain tumours on the surface of the skull, pulsatile, erectile, and the seat of blowing arterial murmur, which had eroded the bone ; there were similar formations in the external soft parts ; they were composed of dilated \u201carterial capillaries.\u201d A man was admitted some years ago into Univ. College Hospital (Mus. Model 2854), under Mr. Liston, having a series of pale red, knotty tuberosities, extending from the left orbit to the occiput, pulsatile, erectile, and the seat of blowing murmur at a particular point. Death ensuing, Mr. Marshall examined the larger of the series, and found that it consisted in the main of dilated and tortuous arteries, with intervening fibrous tissue and granular fat ; large straight veins existed, and one or two of these uniting at obtuse angles, passed between (but did not communicate with) the arterial branches at the site of the blowing murmur. No true erectile structure was to be seen.\nTumours of this kind (such are many n\u00e6vi, n\u00e6vi verrucosi, and aneurisms by anastomosis), because physiologically erectile, have been","page":127},{"file":"p0128.txt","language":"en","ocr_en":"128\nPRODUCTS, ADVENTITIOUS.\npresumed to be anatomically so, and confounded with Growths composed of true erectile tissue.\nAllied, at least in its functional characters, to angeiectoma, is the growth composed of true erectile (or cavernous) tissue. Soft, doughy, pseudo-fluctuating, pulsatile, erectile, the occasional seat of tactile fremitus and blowing murmur, occurring generally in a single, but sometimes in many spots, commonly cutaneous or sub-cutaneous, but liable to grow in deep-seated parts, congenital or accidental, rarely exceeding a Seville orange in size, and often very small, traceable in rare cases to the influence of pressure or other external injury; sometimes of rapid, oftener of very slow progress; the true erectile tumour has a structure perfectly assimilable to that of cavernous tissue, and, like this, a structure not yet thoroughly unravelled. On section these growths {fig. 94) exhibit\nFig. 94.\nSection of a true erectile growth. ( U. C. Mus.')\non a coarse scale the interlaced columnar appearance of erectile tissue : the trabeculae vary in thickness and density, and are provided with minute vessels ; the hollow spaces between these are shallow or deep, narrow or broad, quadrangular or triangular, and communicate with each other. Microscopically the trabeculae are found to be composed of fasciculated, cellular or fibrous (in very rare instances of intermingled elastic) fibrils, coated with tesselated epithelium, which consequently also lines the hollow interspaces. When these trabeculae are in process of growth they contain fusiform cells.\nSuch Growths are never encysted, but they sometimes acquire a secondary capsule of condensed cellulo-fibrous membrane. It is said they are sometimes lobulated, a condition in which we have never seen them. They are rapidlyregenerated if imperfectly removed. Particularly when connected with the skin, erectile structures may become the seat of cancerous formation.\nErectile Growths generally appear in superficial parts, the skin and subjacent cellular membrane ; the mucous membrane of the anus (as a rare variety of pile) ; the gingival membrane (?) ; the tongue (Brown, in Lancet, 1833). Mr. Liston (Med. Chir. Trans, vol. xxvi.) describes an erectile tumour (Univ. Coll. Mus.) seated in the substance of the semi-tendinosus muscle; Andral (An. Path. i. p. 463) speaks as if the structure were not\nuncommon in the intestines,\u2014 but we have never seen it here ; Lobstein describes it in the liver (?) ; Rayer (Maladies des Reins, t. iii. p. 612) in the kidney.\n\u00a7 5. MELANOMA.\nMelanie cell-pigment, as described in a previous page (p. 116), may be deposited in the substance of various Adventitious Formations, \u2014of Deposits (e. g. Tubercle), of Growths (e. g. Cancer), and of Pseudo-Tissues (e.g. Ossiform structure). Growths, more or less deeply tinged by its presence, have been distinguished as a special class of products under the title of Melanotic Tumours or Melanomata. Whether they have any real claim to such distinction will be best argued, when we have, in as few words as possible, glanced at the structural characters of Tumours of black colour.\nThese tumours are, in some instances, sarcomatous, in others composed mainly of enlarged vessels, in others cystomatous, in others finrous, \u2014 the pigment being deposited between or within the convoluted fibres or vessels of the mass. But no growth contains melanic pigment so frequently as cancer. Studded in points through the cancerous masses, accumulated in lumps or equably infiltrated through their substance, the cell-pigment gives them a peculiar dark colour. This discolouration is by far the most common in the encephaloid species, and occurs most frequently in cancer of the eye, skin, and liver, but is not peculiar to any locality.*\nMisled by the frequency of this discolouration of cancerous tumours, various writers have endeavoured to rank \u201cMelanosis\u201d generally as a .cancerous disease. Lorinser, Laennec, Dupuytren, Alibert, Meckel, von Walther, and Cruveilhier, for instance, take this view of its nature ; and more recently Miiller has described \u201c carcinoma melanodes\u201d as one of his six species of cancer, holding as distinct and individualized a place in the class as Encephaloid or Scirrhus. The following reasons lead us to dissent altogether from these doctrines. (1.) That melanic pigment should in itself constitute cancer is an impossibility ; it never even forms a stroma, as the cells continue permanently free. (2.) The stroma of many melanic tumours (as of those above referred to, fibrous, &c.) is perfectly distinct in its physical and chemical characters from all cancerous stromata. (3.) The microscopical characters of the pigment-cells and granules are the same in tumours of cancerous nature and in non-cancerous growths. (4.) Melanic tumours, when free from acknowledged cancerous elements, cause no special, local, or general symptoms. (5.) When melanic tumours give rise to the symptoms of cancerous disease, their solid stroma is found to be composed in whole or in part of encephaloid, scirrhus, or colloid. (6.) Neither the local nor general symptoms of cancers are\n* The Univ. Coll. Museum contains a model of melanotic encephaloid of the vertebr\u00e6 and spinal meninges.","page":128},{"file":"p0129.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nmodified by the presence of cell-pigment within them. (7.) \u201c Melanotic tumours\u201d are rarely solitary, it is urged by Cruveilhier; but this simply depends on the fact, of ence-phaloid cancer being the growth most frequently impregnated with black pigment.\nThe stromata above referred to are the only kinds which we have ourselves seen or known of as elements of black coloured tumours in the human, subject.. But in the horse a species of melanic mass of different constitution is frequently met with ^ and may, for aught we know to the contrary, occur (if so, probably only in rare instances,) in the human subject.\nThese masses are of lobulated form, perfectly and deeply black in colour, sometimes attain great bulk, and feel remarkably elastic and spongy. Of the numerous specimens of the kind in University College Museum, an attempt has been made to inject one with a white material ; a few spots of white colour in the substance of the tumour alone give evidence of the attempt ; no trace of vascular arrangement is perceptible. A portion of the mass having been allowed to macerate in chlorine water for four days, the colour was rendered sufficiently faint for observation of the stroma. It consisted of delicate fibrils (gelatinizing with acetic acid) arranged parallel to each other, without the least appearance of meshes. The pigment-granules, which were not contained within cells, (at least, no cells were visible), lay upon the surface of the fibres in some1 places, so as on first sight to give an appearance of cross lines ; in others they lay between the fibres.. The conviction arises that this tumour may have been a haematoma; absolute proof is, we admit, yet wanting: if we are right, it would follow that the only doubtful kind of black tumour we have seen, possesses in reality, like all others, a stroma of ascertained nature* with black pigment added. And the observation lends indirect support to the view (still unestablished) of those who presume black pigment to be, under all circumstances, formed from the colouring matter of the blood.\nOf Fat-Basis.\nGrowths of fat-basis agree in not being properly encysted, though they may occasionally acquire a secondary capsule from condensation of adjacent cellular membrane. The chief species are Lipoma, Steatoma, and Cholesteatoma,\n\u00a7 1. LIPOMA.\nLipoma is a growth of softish consistence, somewhat elastic in form, generally disposed to be globular, though occasionally distinctly flattened ; frequently lobulated, and furrowed on the surface ; varying in size from very minute to vast dimensions, weighing from a few grains to ten, twenty, or (if records be true) forty pounds; ordinarily single, especially when of notable bulk : \u2014 two or three of the size of the clenched hand may, however, not unoften be seen together ; and occasion-\nVOL. IV.\n129\nally, when of very small size, considerable numbers coexist in the same individual.\nLipoma most commonly forms in the subcutaneous adipose texture (where it partakes of the characters of hypertrophy), but appears to be producible wherever cellular tissue exists. Miiller has seen a lipoma between the corpora albicantia and optic nerve ; Albers (Pathologie, b. ii. s. 189), found a lipoma of the size of a mushroom between the arachnoid and dura mater, on the level of the fourth lumbar vertebra ; Andral (Anat. Path. ii. 412) describes one as large as a walnut, seated in the walls of the vena port\u00e6. Growing between the peritoneum and abdominal wall, lipoma sometimes escapes by the abdominal rings, and constitutes the so-called \u201c fatty hernia,\u201d In a fatal case of infiltrated cancer of the right lung,, which lately occurred in our wards (Univ. Coll. Hosp.) a lipomatous mass had formed in the pleura of the affected side.\nLipoma on section, and even externally, presents the appearance and possesses the physico-chemical properties of common adipose tissue. The fatty elements, (margarin and olein) are removable with boiling aether. Microscopically the fat is found to be contained in cells, of the natural size, aggregated in parcels amid and upon the fibres of a delicate cellular tissue ; the dimensions of the mass have no influence on its intimate constitution. The cells commonly of rounded shape, become much more rarely polyedral from lateral pressure, and are for the most part non-mucleated.\nTheir contained fat is fluid at the temperature of the body : when cool, separation of the olein and margarin takes place (as shown by Messrs. Todd and Bowman in the case of natural fat) ^nd star-like groups of crystals of the latter form in the interior of the cell. We have occasionally seen free oil globules in lipoma, but whether arising from accidental rupture of containing cells or not, we cannot determine. The vessels of lipoma are of small size, and ramify in its stroma.\nA delicate laminar cellular membrane invests the majority of lipomat-a ; infiltration of texture is never effected by these growths. Their cellular investment may become fibrous, giving them a pseudo.-encysted character. Peduncuiation (single or multiple) is not uncommon ; the peduncle sometimes stretching away to some distance from the main part of the growth; from the front of the sternum, for instance, deeply into the mediastinum.\nThe natural course of lipomata is to increase almost indefinitely in bulk, without giving rise to any other inconvenience than that arising from their size, weight, and position. The surrounding skin bears without ill results an extraordinary amount of distension ; though eventually attenuation, low inflammation and gangrene have sometimes ensued. Lipomata are susceptible of inflammatory softening, (a rare occurrence however) leading to breaking down of their substance ; the physical, and probably chemical qualities, of the fat change materially. Growths thus altered have\nK","page":129},{"file":"p0130.txt","language":"en","ocr_en":"130\nPRODUCTS, ADVENTITIOUS.\n\u201c become cancerous,\u201d in the erroneous language of their describers ; we have never seen or read of a satisfactory example of cancerous formation, from a basis of lipoma. Fibrous thickening of the cellular septa of the growth is not uncommon ; but a true fibroma is never evolved from a lipomatous tumour. Absorption of the fat may be effected by artificial pressure; the residual cellulo-fibrous structure forms a more or less dense mass.\nLipoma with excess of cellulo-fibrous stroma, much firmer than the simple variety, and more frequently invested by a pseudo-cyst, has been described under the names of Adipose Sarcoma, and Lipoma Mixture.\nLipoma has sometimes a semi-transparent almost gelatiniform look, the cause of which is not clear.\nMliller proposes the title of lipoma arbores-cens for certain rare adipose formations, found in the joints. They originate behind the free part of the synovial membrane, protrude into the joint, and form tufts, nodulous at the ends. They are said to be most common in the knee-joint. The pleural lipoma, just referred to as having occurred in our own practice, might be accredited to this variety.\n$ 2. STEATOMA.\nThere is a variety of fatty growth of greater density and solidity than lipoma, close in grain, inelastic, opaque, having the aspect of suet or sometimes of putty, wholly unlike natural adipose tissue. Such tumours, to which the name of steatoma is given, are composed of fat, soluble in boiling alcohol, non-vesicular, granular, and amorphous, and aggregated into masses without the intervention of cellular tissue. These accumulations sometimes acquire great bulk ; we have seen them in the mesentery, testicle, and mediastinum.\n\u00ff 3. CHOLESTEATOMA.\nSee Cholesteric Fats (p. 94),\nOf Gelatin Basis.-\n$ 1. FIBROMA.\nFibrous Growths appear naturally to affect the spherical form : they may, however, be accidentally flattened (as in the walls of the uterus, during the advance of pregnancy, Univ. Coll. Mus.) ; pedunculated (seep. 122) under the mucous membrane of the nose and uterus ; or nodulated from having two or more centres of development. They may be smaller than a pea (in the dura-mater for instance); or, especially when developed under the peritoneal coat of the uterus, exceed the head of an adult in size : tumours of this kind have been known to weigh 25, 30, 35, and 39 pounds. Their external surface is naturally smooth and even ; loose filaments of cellulo-vascular tissue form their common material of union with adjoining textures ; in some cases the connection is rendered unusually intimate by exudation-matter. (See p. 125.)\nOn section the colour of these growths is generally found to be greyish-white,\u2014thegrey-ish colour being that of the intrastromal matter, the white (which may be dull or glistening) that of the stromal. Less commonly fibroma has a reddish hue. The consistence of the mass varies with its colour : the greater the whiteness, the greater the density, specific gravity and tenacity of the tumour ; the reddish coloured growth is comparatively soft and yielding.\nThe constituents of fibrous tumours visible with the naked eye, are white bands ; a material interposed between them of darker colour, less opaque, less dense, and less manifestly fibrous ; and, in comparatively rare cases, vessels, \u2014 congregated in the main towards the periphery of the mass. The arrangement of the white bands and of the enclosed darker substance is peculiar: the bands follow an irregularly curvilinear direction ; the loculi hence affect the spheroidal or oval shape. This character helps to distinguish fibroma from scirrhus with great excess of fibrous stroma ; in such scirrhi the fibres always exhibit a tendency to rectilinear arrangement. By firm pressure a transparent, pale straw coloured (never lactescent), and glutinous fluid may be forced from a fibrous tumour : its quantity is very small, and it maybe infiltrated through the growth or accumulated in spots.\nMicroscopically these growths are found to consist of fasciculated and intertwined fibres, less undulating in direction and less clear in outline than those of natural fibrous tissue, arranged parallel to each other, and studded or not with minute inequalities, produced by the still remaining nuclei of original cells. In the soft fibrous tumour this filamentous element is the same in character as in the hard ; but it is less abundant, less closely set, and scarcely fasciculated : in this variety, too, it is more common than in the hard, to find cells with granular contents, some of them assuming the fusiform shape. We have occasionally seen fat-granules in these tumours ; but fat is never one of their predominant elements.\nWhen submitted to ebullition, the entire mass of a fibrous growth is converted into a jelly (glutin), with the exception of a very minute quantity of protein substance, derived, probably, from associated blood : the walls of the few cells, such tumours contain, are insufficient to account even for that minute quantity. Their saline constituents are, in various proportions, those of the blood. Valentin attempts to show that fibrous tumours of the uterus are sometimes composed of fibrin : doubtless, as we have already explained (p. 126) h\u00e6matomata of the uterus occur, and may undergo evolution into fibrous tumours : but we altogether discredit the alleged fact, that tumours exhibiting the microscopical constitution of fibroma, are ever of protein-basis.\nThe nature of fibroma leads it simply to enlarge, without change in, or around, itself. Some alterations of texture are so common.","page":130},{"file":"p0131.txt","language":"en","ocr_en":"131\nPRODUCTS, ADVENTITIOUS.\nhowever, (the so-called cartilaginification and ossification) as to have passed for phases of evolution of fibroma; others (congestion, inflammation, serous infiltration, haemorrhage, deposit of melanic matter, precipitation of fat, great development of vessels, and cancerous formation,) are, on all hands, confessedly morbid.\nPatches, more or less extensive, and having the outward appearance of cartilage, are of common occurrence in fibrous tumours. The period at which this change occurs is indeterminate; nor has the size of the growth any appreciable influence upon it. We have examined some specimens of this kind without detecting any cartilage corpuscles, and incline to regard the outward change as simply signifying an increase of density and closeness of deposition of fibres.\nNor is the alleged \u201c ossification \u201d of these tumours, according to our observation, more real. We have not succeeded in detecting in the ossified-looking parts either the corpuscle or the laminated structure of bone, but simply saline particles or granules closely or loosely set in the organic basis of the tumour : actual ossification has, however, sometimes been seen. This saline precipitation commences indifferently in any part of the mass, and commonly shows itself in several points simultaneously, these being usually seated near the centre ; it is far from unusual, however, to find most accumulation at the periphery, and not a few cases have been mentioned by Meckel, Louis, and others, in which the central parts, still fibrous, have been found encased in an earthy shell of variable thickness. The density of the calcareous matter (grey or yellowish in colour) varies greatly. If it be most common to find this substance friable and porous, in other cases, the saline substance is extremely hard and dense, resembling marble or eburnated bone. From Professor Darnell\u2019s analysis of a large tumour, described by Mr. Arnott (Med. Chir. Trans, xxiii. p. 202), we may infer the great extent to which the animal constituents may be replaced by inorganic salts, as also the nature of these : here were found, animal matter, including ivater and ammoniacal salts, 35 ; phosphate of lime, with a small quantity of phosphate of magnesia, 56 ; carbonate of lime, 5 ; alkaline sulphates, phosphates, and muriates, 4=100. The extent of the growth converted into calcareous matter varies greatly. Bayle refers to a tumour larger than a new-born infant\u2019s head, containing ten points of \u201c ossification,\u201d\u2014the larger scarcely the size of a pea, the smaller not bigger than a grain of wheat : Mr. Arnott\u2019s case exemplifies the opposite extreme of almost total conversion into saline substance. When either converted altogether into earthy matter, or provided with an earthy crust of variable thickness, these bodies have been described as \u201c calculi.\u201d Occurring most frequently in the uterus, these concretions of fibrous origin have also been observed in the cranium by Cruveilhier (Rev. M\u00e9d. Sept. 1833), by Krull and others.\nWe have seen one as large as a walnut, which had been connected with the integuments of the face, in the possession of Mr. Liston.\nThe period at which calcareous deposition commences is altogether accidental. The size of growths has no influence upon it : the largest tumour we ever met with contained not a single earthy particle, visible with the naked eye ; while it is common to find very small growths partially calcareous, and small and large tumours in the same uterus may present this change to an equal amount. It has even been maintained by Sebastian, that ossiform deposit is more common in small than large tumours ; but although this idea may be rendered probable \u00e0 priori by the consideration that the occurrence of this change would prevent further enlargement of the proper fibrous structure, yet we doubt strongly its being supported by facts. With the progress of saline precipitation (obviously so when the earthy changes occur on the peripheric surface, less distinctly and rapidly, though not less really, when they arise in the central parts) the connection of these, growths with surrounding tissues, becomes less and less intimate ; the vessels undergo obliteration, and a few filamentous shreds may alone keep up the union, until eventually the calcareous mass ceases to have structural connection with the organs. This condition is in some cases the prelude to its expulsion from the body. Th\u00e9 saline matter sometimes appears to act as an irritant on the adjoining fibrous structure, and induce local exudation, suppurative or otherwise ; probably this is the state referred to by Bayle, as \u201ccaries\u201d of the alleged osseous structure of a fibroma.\nFibrous tumours, of the reddish variety, soft, vascular, and of loose texture, are subject to internal congestion, which when these growths are situated in certain situations, as for example, under the mucous membrane of the uterus, may, aided by expulsive efforts of that organ, lead to rupture of the superficial layers of the growth, and terminate in external haemorrhage. According to Madame Boivin, such tumours may be regarded to a certain extent as of erectile nature, inasmuch as they admit of becoming hard and tumid with blood at certain periods, esp\u00e9cially the catamenial.\nHaemorrhage into the substance of the growth is a condition occasionally observed. Andral has noticed it, and we have seen a tumour containing a clot of considerable size.\nNumerous small cavities are occasionally observed in these masses filled with red, and manifestly bloody, serosity ; doubtless blood in an altered condition. These accumulations saturate and disintegrate eventually much of the solid substance.\nLike all vascular structures, these growths are occasionally seized with inflammation \u2014 the hard variety much less frequently than the soft. This occurrence may be announced by severe local and general symptoms, increased by the participation of the surrounding tissues. The products of inflammation exuded into the substance soften and disintegrate it ; pus of\nK 2","page":131},{"file":"p0132.txt","language":"en","ocr_en":"132\tPRODUCTS, ADVENTITIOUS.\npure character is rarely observed however. The tendency to inflammation is extremely slight, inherently, in these formations ; when it occurs, it arises as a secondary consequence of their mechanical action on surrounding parts. This action produces various derangements of function of those parts, which are followed in them by irritative action, eventually spreading to the adventitious mass. The proof is, that growths so seated as not to lead to irritation of adjoining textures (sub-peritoneal pedunculated uterine tumours, for example) never, so far as our own observation and all recorded experience goes, become the seat of inflammation. We do not, however, mean to deny that in tumours of soft texture and abundantly vascular, an intrinsic process of inflammation may not possibly arise. Sphacelus may be the result of the former kind of inflammation ; but this change, according to our observation, very rarely occurs with its ordinary anatomical characters.\nMelanie colouring matter is sometimes deposited in abundance in these growths. Dr. Carswell (Elementary Forms of Dis. Melanoma, pL 1 . fig. iv.) has figured a very beautiful and characteristic specimen of this kind.\nThe softer species of fibrous mass has in the uterus been sometimes found to contain steatomatous matter and hair.\nKrull has given a rough sketch of a uterine fibrous tumour, the central part of which contained vessels, some of them capable of admitting a pen, and said to present somewhat the characters of \u201c erectile tissue\u201d\u2014a term very vaguely used.\nDifferent notions have been held as to the possibility of fibrous tumours \u201c becoming cancerous,\u201d The difficulty in deciding this question has arisen from the total want of definite meaning in the minds of authors as to what constitutes \u201cbecoming cancerous.\u201d If the phrase be applied in the manner which seems the only rational and sound one, that is, to parts, whether adventitious or not, in which the development of one or the other of three species of cancerous formation occurs, the perplexity of the question vanishes at once. The growth of cancerous substance in fibrous tumours is, in truth, at the least, materially more rare than in any natural vascularized tissue. We have never ourselves seen a particle of true scirrhus, encephaloid or colloid, in the interior of a fibrous tumour proper. The assertion of Dupuytren and certain of his copyists, that fibrous tumours frequently become carcinomatous, is easily explained ; they confound the fungative and intractable sores sometimes arising on the uterine surface and adjoining sub-mucous fibrous tumour, with cancerous disease\u2014applying the term, with a vagueness subversive of all correctness in morbid anatomy and in pathology, to every sore resisting treatment and affecting the constitution by its discharge and irritative agency. As well might they call the fungating sore, produced in the tongue or cheek by a carious tooth, a cancer.\nThe total expulsion of fibrous tumours from\nthe body, is a phenomenon of less uncommon occurrence, than is usually supposed. It is effected while the mass possesses its original fibrous constitution, or after its conversion into earthy matter : the process in the latter case is much simpler than in the former, as the organic connections of the mass have been gradually destroyed in the manner already referred to ; it is likewise of much more frequent occurrence. While yet fibrous, the growth may be expelled as a single mass or piecemeal; more rarely in the former way. The conditions necessary for its accomplishment are, that it should be separated from its connections, and, this once effected, that it should be so seated as to drop from the body spontaneously, or be under the influence of some expelling force. In the case of the uterus, the expulsive efforts of the organ lead to the removal of the masses (especially if seated under the mucous membrane) at a much earlier period, than their mere anatomical state would lead us to expect. The museum of University College contains a portion of fibrous tumour, expelled from the uterus in this manner ; submitted to microscopical examination, we found it composed of precisely the elements already described.\nThe constitution of these growths would lead us to expect their local reproduction, if partially removed. Observation confirms this view. Cruveilhier describes, from the practice of Dupuytren, a case of fibrous tumour growing from the interior of the body of the lower maxilla, in which reproduction took lace twice after imperfect removal with the nife.\nThe simple tissues in which fibrous tumours are observed are : the cellular ; the fibrous ; rarely, if ever, the osseous properly so called ; the nervous. The compound tissues and organs in which they are more or less frequently developed are : \u2014 the bones, in immediate connection with the endosteum, or more especially the periosteum; the submucous tissue of the pharynx, more rarely of the oesophagus, of the stomach and intestines ; the subperitoneal tissue; the submucous tissue of the larynx, the nares, the frontal and sphenoid sinuses ; the sub-pleural tissue ; the arterial tissue; the ovaries; the Fallopian tubes ; the uterus the vagina ; the mamma; the testicle ; the dura mater in its subjacent cellular tissue ; the nerves ; the thyroid gland ; the thymus gland. Of these various parts, the uterus, dura mater, ovary, and mamma suffer, especially the two former, with incomparably the greatest frequenc}\\ A single one, or several fibrous tumours may exist in the same body. Usually numerous, for example, when affecting the dura mater; they are commonly single in the bones. Their coexistence in several distinct organs is extremely rare.\nENCHONDROMA.\nEnchondroma (from eyxovSpo\u00e7, cartilaginous,) is the name recently proposed by Muller for a species of cartilaginous growth, not unknown to previous observers, but by","page":132},{"file":"p0133.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t133\nmany surgical writers confounded, under the erroneous name of \u201c cartilaginous exostosis \u201d (erroneous, if for no other reason, because the formation in question may spring from other tissues than bone), with products of essentially different character, and by some other authors described as colloid cancer.\nWhen uncut, enchondroma exhibits itself as a tumour of moderate size and spheroidal non-lobulated shape, encased in cellular membrane, or (if it spring from bone) in periosteum, ossified or not. The section discovers a firmly gelatinous substance, rather pellucid, of very pale greyish or greenish yellow tint, set (without firm adhesion) in loculi inclined to spheroidal outline, varying in size, and having their walls formed of a dense dull white tissue (fig* 95), One of the rough marks\nFig. 95.\nSection of Enchondroma. (After Miiller.)\nof distinction between this growth and colloid cancer consists in the mode of arrangement of the walls of the loculi : in the latter, when fully grown, the walls seem cut across sharply at right angles with their course ; in the former it is extremely common to find the walls exhibiting flat and extensive surfaces to the eye, as though tbe loculi had been opened to a very small extent only.\nThe general mass is firm ; when the investment is periosteal or bony, proportionally increased. The intra-locular matter is in itself soft, yet has a sharp fracture. Bony matter in its interior of course increases its consistence, and may be formed of: 1, the walls of the loculi converted into thin osseous plates, which give a crackling crispness to the mass; 2, particles of the spongy tissue of the original bone in which it has grown ; 3, sta-lactiform osteoph) tes springing into its substance.\nNo appearance of vessels strikes the unassisted eye in these masses ; but von Walther and Weber (Gr\u00e4fe and Walther\u2019s Journ., b. xxiii. s. 351.) are said by Miiller to have injected the walls of the loculi.\nMicroscopically examined, the fibrous portion of the growth is found to be composed of transparent interwoven fibres. The jelly-like part consists of cells several times larger than the red blood-corpuscle, generally speaking, containing only nuclei in their interior, but in some instances two or three sub-cells, each provided with its own nucleus. The\nnuclei, flattened, oval or circular, vary in diameter. The cells (except in excessively rare cases) are in close contact with each other, and no inter-cell substance discernible between them : the cartilaginous material does not advance beyond the embryonic stage. Such is Miiller\u2019s description ; but it is certain that tumours having the characters of enchondroma perfectly developed to the naked eye, and yielding gelatin, may be wholly deficient in cartilage corpuscles, and contain simple granulated cells in a fibrous stroma.\nSpiculated bone corpuscles are sometimes scattered through the tumour.\nFrom this account it would appear, that although the endogenous mode of growth of the cells occurs occasionally in this formation, it is neither uniform nor constant ; their development proceeds more frequently from blastema lying outside such cells as are already evolved. The endogenous development was observed especially by Miiller in an enchondroma of the parotid gland. Whether the inter-cell substance is generated by thickening of the walls of the cells, or by the hardening of a blastema unconnected, except in respect of proximity, with these, is matter of dispute. Enchondroma is essentially composed either of chondrin or of glutin ; of the former in by far the greater number of cases ; of the latter, in Miiller\u2019s specimen connected with the parotid gland, and in another connected with the ileum, recently added to the University College Collection.\nThe bones are the favourite seat of this growth. Miiller has collected thirty-six cases, in thirty-two of which those organs were affected : the metacarpus and phalanges 25 times; the tibia 3 ; the ileum 1 ; the cranium 1 ; the ribs 1. Of the four remaining tumours, 1 existed in the parotid ; 1 in the mamma of a dog; 2 in the testicle. In its favourite seat \u2014 the metacarpus and phalanges \u2014 this disease produces singular distortion and irregular tuberousness of the hand (fig. 96),\nFig. 96.\nEnchondroma, from model in Univ. Coll. Mus.\nEnchondroma, springing from bone, is invested or not with a bony capsule. When it grows in the interior of a long bone, expansion, and not perforation of the shell, occurs; the cancellated structure first, and then the\nK 3","page":133},{"file":"p0134.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n134\ncortical, undergo softening and rarefaction, and are gradually spread out into a globular sac. New bony matter is also thrown out, helping to complete the capsule, which is, even with this assistance, commonly imperfect. When developed in bones of very spongy texture, perforation may, according to M\u00fcller, occur, instead of expansion ; we believe that, in at least some such cases, the growth originates in the sub-periosteal cellular membrane. In this latter variety the form is less regularly spheroidal than in the other ; but the texture is the same in both.\nThe progress of enchondroma is slow ; its effects fundamentally are purely mechanical. Adhesion of the skin only occurs as an accidental effect of inflammation : rupture of that membrane only from excessive distension ; the resulting ulcer may discharge abundantly, and inflammation arise from this cause, as from external injuries, but not apparently from intrinsic spontaneous changes.\nEnchondroma of the bones, like every other affection of those organs attended with enlargement, has been described under the names osteosarcoma, osteosteatoma, and spina ventosa\u2014terms devoid of definite signification. Scarpa speaks of it as \u201cmalignant exostosis,\u201d a double misnomer\u2014for its course differs essentially, as has been seen, from that of cancerous maladies, and it does not necessarily spring -from bone.\nColloid cancer might possibly be confounded with enchondroma. We:have already alluded to a rude mark of distinction between the two products ; further,-colloid cancer rarely (never so far as our experience goes) occurs in bone, the chosen site of enchondroma ; the effects of the two products on adjoining tissues are essentially different \u2014 enchondroma never infiltrates structures, colloid frequently does ; colloid never contains patches of bone, enchondroma does so commonly ; colloid is of protein basis, enchondroma yields chondrin, or (rarely) glutin.\nCertain sarcomata of the maxill\u00e6 have much outward resemblance to enchondroma ; but they contain spherical cells with granules and fusiform corpuscles, and are besides of albuminous composition.\n\u00a7 3. OSTEOMA.\nThe arrangement of abnormal ossifications has puzzled more than one pathologist. Excluding exostosis and hyperostosis (mere local and general hypertrophies) we propose to examine here all varieties of bone-production in unnatural sites. We adopt this course, in order to avoid recurrence to the subject under the head of Pseudo Tissues, being aware that ossiform masses, having the generic attributes of Growths, ought alone to figure in the present place. Hypertrophy and new production of bone, as in the venereal node, are frequently associated ; and adventitious bone (whether springing from a new cartilaginous matrix or not) is very rarely perfect microscopically, perhaps never so chemically : two fundamental propositions.\nAdventitious bone forms (a) as an infiltration of natural tissues ; (b) as the callus of fractured ^cartilage ; (c) as an osteophyte ; (d) as an ostema ; (e) as an osteoid ; {/) as an infiltration of new products.\n(a)\tIn the natural tissues. Articular cartilages ossify in some situations with advance of life, as for instance, in the cranium ; the material uniting eroded articular surfaces ossifies ; ossification of the costal and laryngeal cartilages (perhaps more common in phthisis, in proportion to the age at death, than in other maladies) is affected by calcareous deposition in the cartilage cells and inter-cell substance, and by generation of new bone lacun\u00e6. Cartilage morbidly ossified, as that naturally ossified, yields glutin and not chondrin. The anterior vertebral ligament is sometimes ossified in tubercular caries of the spine. We have seen the tendons of the legs infiltrated with ossiform substance. The fibrous capsules of the spleen and kidneys are sometimes thus affected, and aponeuroses and fascice are often, and the elastic ligamentum nuch\u00e6, more rarely, in a similar predicament. \u2014 Cellular membrane. The submucous tissue of the gallbladder; the subserous of the pleura (as a specimen before us proves) ; the subretinal ; the intra-muscular ; the parenchymatous (of the liver) ; are all the occasional seats of bone development. Muscle has disappeared and been replaced by bone in some rare cases ; the crystalline lens has been similarly destroyed.\n(b)\tFractured cartilage is healed not by cartilaginous, but by fibrous or osseous, substance.\n(c)\tUnder the name of osteophyte (Lobstein) we include ossiform products generated externally to, but under the influence of, some one of the natural bones. Formed from \u25a0extra-osseous exudation an osteophyte maybe separated from its parent bone, without necessary injury of this (herein differing from true exostosis); and is produced independently of, or in connection with, other preexisting new formations.\nOsteophytes assume shapes singular and various, yet in some measure characteristic of their origin. Thus they are flat, and more or less broad in nodes ; narrow, triangular, and semicircular in cephalh\u00e6matoma ; folia-ceous, {fig. 97), stalactiform, cauliflower,\nFig. 97.\nFoliaceous osteophyte of the clavicle; the foli\u00e6 (6) running at right angles with the accis of the bone (a\\ (U. a Mus.)\n(U. C. Mus.), or stellate, when plunging into soft growths ; styloid when passing in front","page":134},{"file":"p0135.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nof a vertebra destroyed by caries ; sacciform, when investing a soft growth from bone ; wart}', when found about gouty joints ; mem-braniform and lace-like in the cranium of pregnant women.\nThe flat osteophyte (sometimes separable from the subjacent bone) is best exemplified in nodes, though it forms under the influence of common periostitis or adjoining inflammation, as beautifully shown by the ribs of an old sufferer from empyema, preserved in the University College Museum. If a node be carefully examined, it will be found in part to consist of hypertrophy with rarefaction of the superficial stratum of the original bone ; and in part of ossified subperiosteal exudation. The canaliculi in the latter run at right angles with the axis of the bone,\u2014 proving absolutely the existence of a separate centre of ossification : the fact is exemplified on a large scale, in fig. 97. And it is further illusr trated by a portion of carious lower jaw-bone (now before us), separated from the face of a dipper of Congreve matches, labouring under the singular disease peculiar to -workers with phosphorus. On the inner surface of the ramus of the bone (kindly lent to us by Mr. Quain, whose patient the man was *,) appears a flattish osteophyte, partly fibrillar, partly porous and pumice-stone like, of dark-greyish colour, and easily separable at the edge from the maxillary surface : elsewhere are friable earthy-looking particles.\nRut the most singular of osteophytic productions is certainly that which forms in membraniform patches between the cranium and dura-mater of a certain (as yet unsettled) proportion of pregnant women. The natural history of this production (of which a beautiful specimen lies before us) has been unravelled with great sagacity by M. Ducrest.f Exudation matter soft, pulpy, and reddish, forms the matrix of the future osteophyte ; it soon becomes sandy to the feel ; subsequently hard particles of some size are felt, and these form eventually one, more or less perfectly, continuous plate. The frontal regions are its chosen seat, and M. Ducrest shows that its formation occurs symmetrically. _ Its thickness does not exceed a sixth of an inch, and is generally much less ; the specimen before us (irregular thickness from point to point gives this a lace-like appearance) forms a coating for the entire base and upper arch of the skull ; but its superfical extent is very rarely so considerable. When fresh it is of red colour ; twice (in jaundiced women) M. Ducrest found it yellow. This production, which entails no symptoms,- is more prone to appear in young than in more aged women.\n(d) Osteoma. By osteoma we understand a growth composed of bone, and either (a) altogether free from, or (b) having but very slight, connection with any part of the skele-\n* This man is now in excellent health, and manages to masticate with the aid of a fibrous representative of his lost jaw.\nf M\u00e9moires de la Soc. Med. d\u2019Observation de Paris, t. ii.\n135\nton. Tumours of the former kind (a) are of excessive rarity, and are perhaps only met with as results of bony infiltration of a preexisting plastic mass, either of the serous cavities or of the parenchymata ; it seems unnecessary to insist upon the greater frequency of calcification than of true ossification of such masses. Tumours of the latter kind (b) are best exemplified by growths from bone, generally termed pedunculated exostoses, in which the peduncle may be so small, and the body of the growth comparatively so large, that a centre of ossification distinct from the original bone appears to exist. Such productions are not very unfrequent about the phalanges of the toes ; their texture is generally loose, but may be eburniform from density.\n(e) Osteoid. \u2014 Under the names of osteoid or ossifying fungous tumour, Muller describes a growth of slow or rapid course,, generally springing from the surface of bones, sometimes acquiring great bulk, composed of porous or close osseous texture, and of a greyish white, vascular, nodulated substance, of the consistence of fibro-cartilage, the latter lying in the interstices of the former. The softer substance furnishes neither glutin nor chondrin by boiling, and exhibits a dense fibrous rete under the microscope, containing a few nucleated cells in its meshes. The formation of osteoid growths seems dependent on a peculiar diathesis ; they generally appear at first on one bone, but may eventually invade several bones and certain soft parts \u2014 the lungs, great vessels, &c. The removal of a primary growth by amputation does not prevent the development of others internally. Cru veil hier\u2019s osteochondrophyte (Anat. Path, livrais. 34);.is a production of this class ; this writer calls the soft part of the tumour cartilage, but gives no proof of its being so.\n(/) Bone formation in the interior of new products (exclusive of osteophytes springing from some part of the skeleton) is very rare. We have never seen such bone in cancer or in fibroma; but there is sufficient evidence that it has, in some rare instances, been observed.\nOf Undetermined Basis.\nGOLLOMA..\nPerhaps the word Colloma will not be objected to as a pro tempore name for the gelatinous-looking matter, which is of common occurrence in the interior of cysts, and occurs less frequently, unprotected by such investment, in the limbs and elsewhere. Tremulous and soft, sometimes sufficiently so to be almost poured from the part containing it; generally amorphous, sometimes fibrillar, never stromal, as seen with the naked eye, this substance appears transparent and amorphous under the microscope. It contains no interstitial vessels.\nThis substance yields no gelatin by boiling ; nor is it composed of albumen (though it may furnish traces of this principle) : it is therefore chemically different from the jelly-\nK 4","page":135},{"file":"p0136.txt","language":"en","ocr_en":"136\nPRODUCTS, ADVENTITIOUS.\nlike matter of true gelatin-yielding growths, and of colloid cancer ; from both which it also completely differs in structural characters.\nMitller figures under the title of Collonema a soft gelatmiform tumour of the brain (seen also in the breast), composed of grey-coloured cells, a few fibres and vessels, and acicular \u25a0cystals, soluble in boiling \u00e6ther. The reactions of the growth in the brain most closely corresponded to those of ptyalin (?) ; that in the breast contained-a minute quantity .of casein.\nSUB-ORDER II.---INFILTRATING GROWTHS.\nCANCER OR CARCIN031A.*\nIn this sub-order we place as a genus the product Carcinoma, containing three species \u2014 encephaloid or soft, scirrhus or hard, and colloid or jelly-like, Carcinoma. \u201cThe union of these three morbid structures,\u201d as we have elsewhere observed, \u201cinto a distinct genus, is, in truth, not a mere nosological artifice : it is manifest that the formations, to which I thus apply the generic-term cancer, possess characters entitling them to be grouped together, and separated from all others to the generation of which the organism is exposed. They agree anatomically, Tor they are all composed of elements forming a combination without its counterpart, either in other adventitious products or in the natural structures : they agree chemically, for they are ail distinguished by the vast predominance of protein-compounds in their fabric ; they agree physiologically, for they all possess in themselves the power of growth and of extending by infiltrating surrounding 'tissues, and so producing an appearance of assimilating to their proper substance the most heterogeneous materials,\u2014an inherent tendency to destruction, and the faculty of local reproduction; they agree pathologically, for they all tend to affect simultaneousiy or consecutively various organs in the body,;and produce that depraved state of the constitution known as the cancerous cachexia.\u201d But, on the other hand, these three structures are not one and the same ah initio, as is contended by some writers: each maybe developed in the others ; but encephaloid stands apart from its co-species by containing true cancer-elements in greatest abundance, and in the purest and most unadulterated form, \u2014 scirrhus derives speciality from its lavish supply of fibre,\u2014 colloid from an unimitated condition of gelatinousness. And, again, we maintain that the\n* As the present article has already reached a considerable length, and as we have very fully treated the subject of Cancer in another work, we shall confine .ourselves here to a statement of some few facts bearing on the morbid anatomy of cancerous grpwths. We are the more disposed to venture upon this course, as nothing which has, to our knowledge, been made public since the appearance of the work in question, requires us to add to, or take from, any of the doctrines or expositions of fact it contains.\nthree products are not mere varieties, \u2014 they are actual species, because each of them, as just stated, has its own constant structural attribute.*\nThe ultimate elements met with in cancerous Growths are of three kinds,\u2014 essential, almost essential, and merely contingent.\n(a) The essential elements are granules, cells, fibres, blastema, and vessels. Granules exist to various amounts in all varieties of cancer ; average T\u00f6\u00a3\u00f6\u00f6 of an inch in diameter, and either float free, or are seated within cells, or upon or between fibres. They are composed of a protein-substance, or of fat. The cells of cancer are spherical or imperfectly caudate. The spherical variety (sometimes oval or discoid) measuring, on an average, about t-^\u00f6\u00f6 an ioch, may reach only the of an inch, or, on the other hand, attain the diameter of of an inch, in diameter. The cells of small dimensions are particularly to be seen in scirrhus, where endogenous cell--production is-rare ; the bulky class in colloid cancer, where they stand in the relation of parent-cells to a contained progeny of subcells. The thickness and transparency of the cell-wall vary ; it is sometimes collapsed, -sometimes full and tense ; almost always colourless. The caudate variety of cell exhibits itself under two forms : first, that of an irregularly branched corpuscle, having in its interior a spherical cell,itself provided in turn with a nucleus or even containing nucleated sub-cells '(fig. 98) ; secondly, that of the\nFig. 98.\nCaudate cells (from encephaloid of the stomach), containing nucleated sub-cells. Length -fj\u00f6\u00f6th to 330th of an inch ; width 2305th to 2000th inch. Magnified 400 diams. (From Author\u2019s work on Cancer.)\nfusiform cell seen in sarcomatous Growths (seefig. 93, p. 127), and in exudation-matter undergoing development into pseudo-fibrous tissue. The first form of caudate cell is.scattered in an isolated manner through the growth ; the second may accumulate in fasciculated bundles, so as to simulate fibre. -(See fig. 93, p. 127.) The contents of cells are a certain fluid, granules, nuclei, and sub-cells. Granules are abundant in the cells, more-especially, of scirrhus. The nucleus of the cancer-cell is an\n* The division into species is objected to as deficient in the perfection of zoological classifications. Who, except the artificer of the objection, could have imagined, that even an attempt was made to reach such perfection ?","page":136},{"file":"p0137.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\noval, flattened, parietal, comparatively opaque body, generally speaking of large size in proportion to its cell, and often exhibiting a furrow on its surface or indentation at its edge, (see fig. 6, a. of the author\u2019s work on Cancer), a condition preparatory to its splitting into two. Each nucleus is supplied with one, two, or, it may be, so many as four minute bright corpuscles \u2014 its nucleoli, which in turn probably contain sub-nucleoli. When a nucleus splits in the manner referred to, the resultant bodies may be fairly regarded as subcells,\u2014 they are manifestly hollow, granular, and themselves nucleated.* The diameter of the nucleus varies between the ^ and 3-0V0 of an inch, averaging\tQf an inch. Fibres\nexist under different forms in cancer. First, delicate, non-adherent broken fibrils occur in most specimens. Secondly, true fibrous tissue occurs in the loculus-walls of colloid, and forms the stroma of scirrhus. Thirdly, excessively delicate, almost transparent fibres exist in a special variety of soft cancer, the fasciculate. The unevolved blastema of a cancerous growth varies in quantity, and is perfectly fluid, or somewhat viscid. Particles of amorphous substance, gelatinising under acetic acid, may sometimes be found associated with it. The vessels of cancer are either those of the natural structure affected, or are actual new formations ; they are exceedingly abundant or very few in number. The veins are frequently plugged with cancerous matter, so as to prevent them from being injected.\n(b)\tWe are disposed to regard fat as an almost essential element of cancer, (or rather as a substance tending to be produced where-ever cancer exists,) so constant is its appearance, either in the oil-globule or the granule forms (adipose-cells, if present, come from the implicated natural tissue). When fat abounds in these growths, it appears to have the effect of altering the form of the cancer-cell, and certainly modifies the naked-eye characters of the tumour.\n(c)\tThe contingent materials met with in carcinoma are saline particles, crystalline (Op. cit. fig. 11) or amorphous and calcareous,\u2014the latter in very rare instances accumulating sufficiently to become perceptible to the naked eye (calcification ;) crystals of cholesterin and patches of cholesteatoma; perhaps in very rare instances tuberculous depo-sitj\" ; melanic matter ; blood fluid, clotted, in the state of fibrinous h\u00e6matoma, or of \u201c apoplectic cyst exudation-matter with its spherical and fusiform cell ; pus ; and (on ulcerated surfaces) certain epizoa and epi-phyta. The pseudo-tissues which may be actually formed within the area of cancer (any natural texture may be invested by cancer)\n* Where a system of cell-encasement, such as that observed in cancer prevails, it is plain, difficulty must be felt in assigning with precision the titles of sub-cell, nucleus, and nucleolus.\nf We have never seen this, and we know that the naked-eye aspect of tubercle may be simulated in an encephaloid growth by excessive accumulation of fat.\n137\nare epithelium, the cellular, serous, fibrous, and elastic tissues and blood vessel. Spicu-lated osteophytes, preceded (sometimes at least) by sprouting cartilage, not unfrequently plunge into the substance of cancerous growths from some connected part of the skeleton : an isolated generation of true bony structure, in a nidus of blood-blastema, within a cancerous tumour, seems a possible occurrence (it is at the least, a singularly rare one) ; but the possibility of such generation in actual cancer-substance seems only admissible on the principle that the freaks of nature are boundless in their variety.\nBuilt up of materials, such as these, are all cancers. Encephaloid, soft, brain-like, rapid in its evolution, attaining great bulk, highly vascular, prone to bleed and fungate, is microscopically distinguished by its deficiency in fibrous stroma and the abundance of its fluid blastema and its cells. Scirrhus, hard, tough, slow in growth, and reaching moderate dimensions only, poor in vessels, rich in fibre, differs microscopically from its co-species in its abundance of fibrous stroma and the comparative fewness of its cells, which mainly grow on the exogenous plan. Colloid, crisp in its mass, soft in the jelly-like ingredient that fills its loculi (models of the spherical loculus), but slightly vascular and semi-transparent, stands apart microscopically from encephaloid in the well-marked fibrousness of its loculus-walls, from scirrhus in the abundance of its endogenously-growing cells, from both in the abundance of its viscid jelly-like element.\nThe chemistry of cancer is yet in its infancy. Its organic basis is essentially protein, \u2014 its saline constituents those of the blood. That there is a difference in chemical nature between colloid and the other species, seems plain from the fact that the former retains, the latter lose, their transparency in alcohol : Muller conjectures that colloid contains a compound analogous to ptyalin. Microchemically the cells of cancer are insoluble in cold and boiling water, and are not seriously affected (in respect of solution) by acetic acid : the cell-wall has been said to disappear under the influence of the diluted acid ; but it is simply rendered pale, and may be restored by the ioduretted solution of iodide of potassium, which at the same time greatly deepens the colour of the nucleus.\nWe have already said (p. 12-1 ) that a constant and unfailing microscopical characteristic of cancer has hitherto been vainly sought for ; the following propositions will serve as a commentary on, and, in some sort, a justification of, the statement. (1.) Parent cells, containing within them sub-cells having darker nuclei, and these, in turn, bright nucleoli, are strongly characteristic of cancer : but such cells are rare in, and may be altogether absent from, scirrhus; encephaloid in some phases of its growth may also be without them. (2.) The shapelessly-caudate cell (see fig. 98) seems significant of cancer ; but it may be absent from encephaloid, and it is excessively rare in scirrhus or colloid. (3.) A","page":137},{"file":"p0138.txt","language":"en","ocr_en":"138\tPRODUCTS, ADVENTITIOUS.\ntumour may present to the naked eye the characters of encephaloid, be the seat of interstitial haemorrhage, affect the communicating lymphatic glands, run in all respects the course of cancer, and nevertheless contain no cells but such as are undistinguishable, in the present state of knowledge, from common exudation-cells. (4.) Nay more, while a primary \u201c malignant\u201d tumour contains these cells alone, the lymphatic glands secondarily affected may contain compound nucleated cells, spherical and shapelessly-caudate.* (5.) The granular and imperfectly nucleated cell of scirrhus is valueless as an evidence of cancer. (6.) The true fusiform cell (fig. 93) is an adventitious formation when it occurs in cancer, and has no diagnostic signification. (7.) The association of fibre and cell-structure, which will distinguish scirrhus from fibrous tumour, may be totally wanting in encephaloid, and exists in sarcoma and enchondroma. (8.) If fat be associated in large quantity with fibre and cell-structure, the certainty that cancer is present becomes great, but not absolute.\nThe property of infiltration, which serves well, as we have shown (p. 125), to distinguish cancer from other growths nosologically, fails practically in the distinction of tumours generally, because a true cancer is not necessarily infiltrated, and because tubercle and exudation-matter may he infiltrated. In ultimate analysis the single character least likely to deceive is this : if a tumour be cancerous, it will yield on pressure an opaque, whitish (milky or creamy-looking) albuminous fluid f ; if it be not cancerous, it will not yield a fluid of these qualities.\nOrder III. \u2014 Pseudo-Tissues.\nThe blastema from which Pseudo-Tissues are evolved is commonly known as coagulable lymph, itself nothing more than liquor sanguinis slightly modified in nature, and in the proportion of its elements (the modification consisting in excess of fibrin,\u2014it comes from hyperinotic blood, \u2014 and in the presence of gelatin, Mulder), and like it composed of water, fibrin, albumen, fat and salts. Produced by exudation from the vessels, homogeneous and amorphous, this fluid soon becomes the seat of cell-formation, the cell being that already described as the compound granule corpuscle. The fibrin it contains coagulates into patches or flakes of yellowish grey colour, semi-transparent, amorphous to the naked eye, but fibrillar (in parallel fasciculated rows) under the microscope, the cells (and abundant granules) appearing set in or upon the fibrils. H\u00e6matin,\n* Mr. Ellis has recently ascertained this fact in examining a testicle, and communicating lymphatic glands.\nf We have found this the fact even with cancers of excessive transparency and wateriness of look. (See Op. cit. p. 17.) Colloid cancer is comparatively poor in this kind of fluid ; but fortunately its other characters unfailingly identify it.\nor entire blood-disks may appear, and pus corpuscles be produced, amid these coagula.\nNow the issue of this exudation-matter (which seems regulated rather by the constitutional state than by its own nature) may be of two kinds. Either a permanent material sui generis (which, for want of a better name, we will call Induration-matter) is produced ; or a structure resembling some one or other of the natural adult tissues is evolved. The former result signifies a lower plastic power than the latter i the necessity of active congestion for the production of either is more than doubtful.\nINDURATION-MATTER.\nCoagulable lymph, destined to remain in the condition of induration-matter, becomes more and more opaque and solid, and acquires an imperfect fibrous character (as Mr. Gulliver first showed) from simple condensation of the original fibrillated fibrin, and independently of cell-formation. The fibres become thicker, and run more flexuously, as the consistence increases, \u2014 a change probably caused by contraction from removal of water.\nThe properties of induration-matter vary greatly. Of greyish, yellowish, or white colour ; opaque ; fragile and cheesy in consistence, or firm as fibro-cartilage j of trifling, or of extreme tenacity ; rarely crisp, and generally distinctly tough ; commonly elastic ; in its firmest condition creaking on incision ; occurring in the forms of membranous layers, more or less perfect sacs, nodules, patches (plane, puckered, cupulated, or convex), points, granules, wart-like bodies, or altogether amorphous ; essentially of protein-basis, yet yielding gelatin in a certain proportion, prone to contain fat (granular or cholesteric), and often becoming the seat of saline (ossiform) deposits ; induration-matter is perfectly similar to none of the natural textures. As it hardens, its texture densely and closely set, often acquires a chondroid appearance without containing a particle of true cartilage ; it is imperfectly (or not at all) vascular. Microscopically it is found to be unprovided with prolific cells ; nor are the few cells it may contain, nucleated as a general fact. It is rendered pale by acetic acid.\nInduration-matter is endowed to a remarkable degree with the property of slow contraction,\u2014 a property which renders its presence most beneficial or most baneful. It is this property, on the one hand, which in the process of cicatrisation by granulation, reduces within reasonable limits \"the surface of the largest wounds ; while on the other, it may cause painful deformity, as in the instance of burns, or actually cause death, as in the instance of healing intestinal ulcers.*\nPresenting itself wherever vessels exist, and entering non-vascular textures by imbibition ;\n* The cure of ulcers of the small intestine in continued fever and in phthisis, and of the large bowel in chronic inflammation, has more than once proved the cause of fatal stricture. ,","page":138},{"file":"p0139.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\t139\nco-existing with all varieties of textural change, and exercising important influences on local nutrition, induration-matter would require a volume for its full description. We must content ourselves with an enumeration of some of the principal sites in which it occurs. Induration-matter forms: (A.) On membranous surfaces, where it is known under the names of pseudo-membrane, matter of adhesions, &c. Of the serous class the pleura is by far its most common seat ; next follows the pericardium ; then the peritonaeum ; then appear the tunica vaginalis and synovial membranes ; and longo intervallo the arachnoid.* Among mucous membranes it appears on the respiration-surface in croup, plastic bronchitis, and pneumonia (in all which situations it is not distantly allied to diphtheritic deposit), and on the intestinal surface as in dysentery. It appears on the endocardial and valvular surfaces in the warty and granular forms ; in the arteries and veins in the patch-like shape. The so-called glands of Pacchioni illustrate its occurrence on fibrous surfaces (B.) Free in cavities. So it has been occasionally found forming rounded masses in the periton\u00e6al and pleural sacs ; the so-called \u201c loose cartilages\u201d in joints are in the great majority of instances composed of induration-matter ; so too are those small melon-seed-like bodies, producing double saccular distension at the wrist-joint.f (C.) In the cellular membrane. The sub-cutaneous, (less frequently than the sub-mucous, and still less than the sub-serous) cellular membrane, becomes infiltrated with this material ; in parenchymatous cellular tissue it is singularly common. In addition to the ordinary cases of its occurrence in the latter, as aresultof simple inflammation, it constitutes in great part the substance of the morbid element infiltrating the kidney in certain cases of renal disease attended with persistent albuminuria, urine of low specific gravity, anasarca, &c.; infiltrating the capsule of Glisson, it plays a notable (but not the whole) part in hepatic cirrhosis ; and infiltrating the substance of the lung (especially in certain cases of empyema), it converts that organ more or less completely into a chondroid mass. Seated in the intra-serous fibro-cellular tissue of the cardiac valves and chordae tendine\u00e6 (where it is associated sometimes with atheroma) its contractile force produces the puckerings and shortenings so frequently observed. ( D.) As imperfect cicatrix. Wherever a solution of continuity occurs, the cicatrix may be formed of this substance ; take the instance of false joints: in some situations cicatrix seems always to be thus constituted, of which more in the next section. (E.) On new surfaces. Induration-matter may form on wounded, burned,\n* We have never seen arachnoid adhesions, unless in connection with tumour of the brain or meninges. Is idiopathic arachnitis always fatal ?\nt We have found these bodies hollow centrally ; their capsule is composed of amorphous albuminous matter with a little fat, and occasionally calcareous particles.\nand ulcerated surfaces ; and supply a sac more or less perfect round the cavity caused by abscess, tuberculous softening, and fistul\u00e6.\nSUB-ORDER II.\nSIMULATING THE NATURAL TISSUES.\nWhen endowed with higher plastic quality exudation does not remain as induration-matter, but becomes the matrix from which a structure more or less closely imitative of some natural tissue is evolved. This imitation is never perfect, at once physically, chemically, and physiologically,\u2014at least in respect of the higher orders of texture. A pseudo-tissue thus generated may be wholly adventitious ; or partially so, as when designed for the reparation of lost parts.\nEXTRA-VASCULAR TISSUES.\nEpithelium.\u2014 On cicatrising and on fistulous surfaces, on the inner wall, or amid the contents, of cysts, as a coating for h\u00e6matomata, and as a lining for new vessels, tessellated epithelium occurs as a purely adventitious product. The retained and accumulating epidermis forming corns and callosities, or that thrown off in excess from the skin in pi-tiriasis, or from the genito-urinary mucous surface in various states of disease, or from the intestinal surface in cholera, &c., can only be viewed as products of supersecretion. Hypertrophy of the papillae of the skin, with excess of epidermal formation (Univ. Coll. Mus.), a state prone to give rise to obstinate ulceration, cannot fairly be considered under the present head.' Perhaps the epithelium accumulated in cutaneous sacs produced by dilatation and occlusion of sebaceous follicles may be considered adventitious. So likewise are those productions, elongated or flat, known as \u201c horns,\u201d and which are essentially composed of epidermis. Commonly springing from a dilated and diseased sebaceous follicle, and mixed abundantly with fat, slightly with saline matter, the basis of the future \u201chorn\u201d is at first soft, subsequently becomes inspissated and hard, when its increasing dimensions, carrying it beyond the limits of the follicle, place it under the influence of the atmosphere. Layer upon layer of epidermis continues to accumulate at the surface of the follicle, and eventually a conical mass, some inches in length, may be the result. Horny-looking productions sometimes form on ulcerated surfaces, simple or cancerous.\nPseudo-tumours, composed essentially of epithelium, and susceptible of vascularization, form, it is affirmed, on some mucous surfaces, \u2014the uterine for instance. We have not met with productions of this kind.\nNail. \u2014 (See Tooth, p. 143.)\nCartilage.\u2014Adventitious cartilage, at one time believed to take rank among the most common, is now known to be one of the rarest of new formations : the microscope has certainly dispelled a cloud of error on this subject, by simply showing that cartilaginous-looking products are not necessarily","page":139},{"file":"p0140.txt","language":"en","ocr_en":"HO\tPRODUCTS, ADVENTITIOUS.\ncartilaginous. Such products are most commonly composed of dense fibrous substance, or induration-matter,\u2014 as in the instance of so called loose cartilages of joints.*\nAdventitious cartilage is either of the embryonic or adult type : the former has already been described under the name of enehon-droma. Cartilage of adult type, certainly, sometimes forms the matrix in which adventitious bone originates ; this we have seen beautifully exemplified in spicular osteophytes. Analogy would lead to the admission that a cartilaginous stage should always precede bone-production ; yet not only is proof of the constancy of this stage wanting, but we have looked in vain for its traces in many specimens of adventitious bone. In a very few preparations of that rare variety of false-joint in which a pseudo-synovial membrane is produced, the bony surfaces (whether from fracture or dislocation) have exhibited a cartilaginous look in patch-work ; but we have not had an opportunity of submitting such a specimen to microscopical examination. Of the appearance of cartilage in various Growths enough has already been said.\nNor is the production of cartilage for reparative purposes more easy. A fractured cartilage unites by dense fibrous tissue, or by bony substance.\nSIMPLE VASCULAR TISSUES.\nCellular Tissue.\u2014Cellular pseudo-tissue is one of the most common of adventitious formations, composed of associated white fibrous and yellow fibrous (elastic) fibrils. But rarely does it possess the character of the natural texture in perfection ; the distinction of its component filaments is less clear, the fasciculation of these less regular than in the typical structure. A more or less successful attempt at its production is made in all cases, where induration-matter forms, \u2014 the highest degree of perfection seems to be attained in old adhesions of serous membranes. A lapse of many months is necessary, however, to mould the new structure into its most perfect attainable form ; while on the other hand, a period of seven days (as we have seen in a fatal case of pleurisy) will suffice for the production of an imperfect tissue of this class.\nSchwannf found that embryonic cellular tissue yields no glutin ; the same fact has been ascertained by SimonJ in respect of the adventitious cellular tissue of condylomata,\u2014 by Gueterbock, in respect of that of granulations. The latter observer found pyin in the water in which the granulation-substance had been boiled. At an early period of formation fibrin is found in association with the principle (tritoxide of protein ?) to which the name of pyin has been given ; eventually glu-\n* \"We should be unwilling to affirm that these bodies are never truly cartilaginous; but we have examined a considerable number without discovering the chemical or textural qualities of that tissue.\nf Untersuchungen, S. 136.\nj M\u00fcller\u2019s Archiv* 1839. P. 26.\ntin is yielded on ebullition, but it may be doubted whether the chemical constitution of the new, is ever precisely the same as that of the imitated texture.\nSerous Tissue.\u2014A single layer of polygonal pavement epithelium, beneath this a basement membrane of singular tenuity, and yet beneath this a stratum of cellular tissue, constitute a serous membrane. This structure is essentially disposed to form shut sacs, and produce and retain a certain secretion. So far we have a texture which is often generated adventitiously ; but if, as is now admitted, natural serous tissue is supplied in its proper substance with nerves*, it becomes a complex structure, of which a perfect adventitious copy is never generated.\nA new serous sac may be produced (a) by modification of natural structure, with addition of a new element ; or (b) be completely adventitious.\n(a) In this class appear those well known cases in which pressure, with or without friction, causes condensation of cellular tissue with production of epithelium, the latter forming a lining for a sac of the former. So are produced new supernumerary burs\u00e6 about the knees, the shoulders of porters, between the skin and bone of stumps, between the skin and spinous processes in spinal curvature, whether primary or from caries, &c.\n([b) Purely adventitious serous tissue is either (a) laminar or (b) saccular.\n(a)\tBy the laminar variety, we understand those strata of pseudo-serous tissue which invest false membranes in serous cavities.\n(b)\tThe saccular variety comprehends cysts, primary and secondary. Pnmary cysts are spontaneously evolved, are capable of indefinite increase in number and size, through some intrinsic force, constitute in themselves the disease where they exist, form the material they contain, are closed on all sides, lined with epithelium, and simple or compound.\nSimple cysts occur singly or in clusters, and may appear in almost every region of the body ; their walls are of variable thickness and simply cellular, fibrous or calcareous ; their contents serous or glairy. The mamma and ovary are the most frequent seats of the clustered simple cyst.\nThe compound cyst (cystoma) is characterised by its faculty of producing secondary cysts in its walls, \u2014 these a tertiary series and so on. Their closest investigator, Dr. Hodgkin, assigns them three chief varieties of form, \u2014 the pedunculated, the intermediate, and the broad-based, for a full description of which we must refer the reader to his treatise.f The growth of the contained cysts is sometimes so active, as not only to give a nodulous outline to the main mass (which may attain enormous bulk), but to cause rupture of the walls of the primary cyst. Various morbid changes, inflammatory and other, may arise\n* Todd and Bowman, Physiol. Anat. p. 130.\nf Morbid Anat. of the Ser. and Mue. Mem* branes, vol. i.","page":140},{"file":"p0141.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\tUl\nin these productions ; carcinoma may even, in predisposed persons, be formed in their walls, but not (so far as evidence goes) be produced in their cavity as an evolution of blastema exuded from their lining membrane.\nMidler has recently applied the name cysto-sarcoma to growths, principally composed of a fibro-vascular texture, but invariably found to contain solitary cysts in their substance. The cysts may be solitary or compound ; the solid substance, of greater or less density, has an indistinctly fibrous structure, contains no cells, and is of albuminous basis. This growth is essentially distinct from carcinoma, but that it differsgenerically from sarcoma seems questionable.\nSecondary cysts are not spontaneously generated, but form through the influence of bodies foreign to the site they occupy : around effused blood, after a series of modifications (the apoplectic cyst), around adventitious products, extra-uterine foetuses, and bodies introduced from without, as musket-balls, shot, pins, &c.\nA sort of pseudo-cyst is sometimes produced by distension and closure of small natural cavities, or of the excretory ducts of glands. In the first class we find dilated cutaneous follicles, intestinal crypts, and solitary glands ; to the second class belong cysts of the lactiferous and pancreatic tubes, of the labial and sub-maxillary glands, some of those in the testicle, and, it is commonly believed, in the kidney*\nFibrous and Elastic Pseudo-Tissues.\u2014Of the production of white fibrous-tissue of an imperfect kind, numerous examples have been referred to in the past pages, \u2014 it is one of the commonest of new formations.\nLess common by far is the generation of the yellow fibrous element, which is distinguished by resisting the action of acetic acid ; the mesh-like arrangement of bifurcated fibres is much rarer in the imitation new tissue than in its prototype,\u2014 nor does the former occur (so far as we knowr) in masses of any size. The modification of this texture which constitutes the main element of artery is doubtless produced in new vessels.\nOsseous Pseudo-Tissue.\u2014The most perfect imitation of a complex natural texture is exemplified by adventitious bone,\u2014 produced for the reparation of injuries (Permanent Callus). It is even said that the permanent callus has all the characters of true bone,\u2014 a proposition which appears to us to require more absolute proof than it has yet received. The new bony shaft, produced to supply the ravages of necrosis of the long bones, is a ruder imitation of original bone ; it is darker in colour, rough, and tuberculated on the surface,\n* Cystic productions in the kidney still require investigation \u2014 from the minute apparently solitary cyst, to those clustered masses causing destruction, more or less complete, of the proper renal substance. Dr. Johnson (Med. Chir. Trans, vol. xxx.) adduces arguments of a novel kind to prove that the simple cyst is in reality a dilated tube; Mr. Simon (eod. tom.) seeks to show that it is a new development within the parenchyma.\nand often much denser than the latter. (See Osteoma, p. 134.)\nNervous Pseudo-Tissue.\u2014In certain of the simpler varieties of neuroma the induration-matter mainly forming the tumour appears to contain a larger proportion of tubular fibres, than would in the natural state fall to the share of a portion of nerve of similar length. The tissue in excess (admitting the fact to be substantiated) might, however, be rather regarded as an hypertrophy than a new production.\nThe regeneration of voluntary nerve (rendered probable by the experiments of Haigh-ton) has been proved by those of Steinr\u00fcck*, Nasse, G\u00fcntherj\", and Schrein. J The tubules produced in the exudation, connecting the cut ends of a nerve, differ from the natural ones in being more widely apart, of smaller diameter, less parallel to each other, more intertwined, and more mixed with cellular fibrils. The time required for their production varies,\u2014a month appears to be the shortest period yet observed ; the length of nerve which may be excised is yet unsettled. In the majority of cases, even where reproduction is seemingly perfect, the physiological action of the injured cord remains imperfect; probably because the corresponding parts of the same fibres are not, or because sensitive and motor fibres are, brought into connection ; besides the new tubules are not the precise physical counterparts of the old, nor is their number as great as in the original texture.\nCerebral substance removed from animals is replaced by a brain-like matter : the precise nature of this matter (as of that appearing in hernia cerebri in man) has not been examined sufficiently. It seems very doubtful that dynamic vesicular texture ever forms adventitiously.\nBlood-vessel.\u2014The development of new blood-vessels, though so common, is but ill understood. They must obviously be produced from pre-existing trunks, or be evolved independently.\nViewed as productions from the old vessels, they have been supposed to be mere prolongations of these,\u2014 a notion set aside by the fact that vessels do not terminate by open mouths. Or, again, they have been considered the produce of a looping process \u2014 the increased impulse of the circulation towards the site of vascularisation being supposed, when combined with a relaxed state of their own texture, capable of elongating the old trunks into loops : it seems probable that increased vascularity may, to a limited degree, be produced on this plan. Or, again, it has been conjectured that processes, first solid, subsequently hollow, spring from the sides of the original vessels,\u2014an hypothesis unsupported by direct evidence and deficient in plausibility. Or, lastly, it has been maintained that the first step in the process consists of rupture of original\n* De Nerv. R\u00e9g\u00e9n\u00e9r\u00e2t. Berol. 1838.\nf M\u00fcller\u2019s Archiv. Heft V. S. 405. 1839.\n+ M\u00fcller\u2019s Archiv. 1840.","page":141},{"file":"p0142.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\n142\nvessels ; the second in the extravasation of blood ; the third in the passage of this into canals (manufactured, as it were, for its reception); the fourth in the formation of walls round this blood : the difficulty in this hypothesis lies in the alleged canal-formation.\nThe notion that new vessels are independent productions is supported: \u2014 by the analogy of the process in the vascular area of the chick ; by the fact that the new cannot at first be injected from the old vessels ; by the analogical fact that new blood-particles appearing in lymph in the frog are of spherical shape (as in the foetal condition), and are therefore not particles previously contained (for these are oval) in the old vessels ; by direct observation both with the naked eye and with the microscope. In truth in one spot of a new material to be vascularized may be seen minute unconnected points of blood ; at another, a number of such points united in linear juxtaposition, so as to form a streak of blood unenclosed in any distinct vessel ; elsewhere a vascular investment is found for a similar streak ; further on a like piece of delicate tube divides at each extremity into a number of tapering ramifications, assuming a stellate arrangement, the whole assimilable to the system of the portal vein, and capable of effecting an independent oscillation of the contained blood. What is thus seen with the naked eye is corroborated with the microscope ; but this instrument has not yet made clear either the precise structural characters or developmental process of the new vessels : we simply know that these are wider, and of thinner walls than natural capillaries. The manner in which communication is effected between old and new vessels (when the latter first become the seat of true circulation) is unknown. That the formation of new blood precedes that of new vessels seems fully established ; just as the cell-structure, destined to fill a loculus in a new growth, forms before the loculus-walls that contain it.\nThe production of new blood and vessels signifies the appearance of various new chemical compounds in the vascularized material ; the globulin formation may be understood, that of theh\u00e6matin is at present inexplicable, \u2014unless we accept the extravasation-theory above referred to, which supplies iron as required.\nFurther observations are wanting as to the shortest possible time in which new vessels may be formed ; we have seen them in peri-ton\u00e6al exudation aged seven days ; Everard Home speaks of their appearance in twenty-nine hours. They form in growths, induration-matter, hypertrophy of natural textures, and pseudo-tissues. Generally produced on a limited, they in rare instances form on an extensive scale ; the most singular illustration of the latter appears in the new system of vessels generated in tuberculized lungs (Schroeder, Guillot), which effects not only a complete change in the anatomical condition, but in the physiological actions, of those organs.*\n* Louis on Phthisis, ed. cit. p. 29.\nErectile Tissue. \u2014 (See Angeiectoma, p.\n128.)\nLym/ph Vessel. \u2014 Schroeder van der Kolk has described lymph vessels of new formation in peritoneal pseudo-membrane ; it is generally admitted that his observations require corroboration, and we know of no other evidence bearing on the question.\nFibrous and Spongy Cartilage..\u2014Fibro-carti-lage forms in some rare instances the material by which imperfect union of bone is effected : its own losses are supplied by a similar material; it does not appear to form in an absolutely adventitious manner. Nor does spongy cartilage grow as a new product,\u2014and of the reparation of this texture little is known.\nHair.\u2014The adventitious production of hairs is not singularly rare, and though, no doubt, much fantastic matter has been written on their places of attachment, the following localisations may be admitted as real. The tongue*, the caruncula lachrymalis, the cor-neaf, the internal surface of the gall-bladder the nymph\u00e6, the vagina, (in connection with fat) tumours of the uterus and of the fauces.\u00a7 Cases of defecation of hair and of pilimiction are for obvious reasons to be received with distrust I ; but the rupture of an ovarian cyst into the bladder may sometimes have caused discharge of hair with the urine.\nCysts of new formation are the favourite site of adventitious hair ; pilous cysts have been seen occupying the ovary, uterus, subcutaneous membrane, muscular substance, walls of the stomach, testicle, liver, thyroid gland, omentum, and periton\u00e6al cavity. The ovarian is of all cysts the most frequent abode of these productions. The hair is scattered through the fatty matter generally present, or adherent to the walls of the cyst, either by a bulb or by simple embedding, or by means of cretaceous particles. The colour of the hairs varies greatly, sometimes even in the same cyst ; their length from a few lines to upwards of two feet. They commonly resemble in structure the hairs of the head, rarely those of the pubis : their possession of roots has been denied ; whereas Meckel considers it probable that they always have a root in the outset, losing it subsequently after separation from their seat of attachment.\nTooth, -r- Teeth are frequently found in pilo-fatty cysts ; there scarcely appears, indeed, to be a single authentic case of the discovery of adventitious teeth (except where produced\n* This has been denied hypothetically; yet nothing is less improbable than the occasional growth of obvious hairs from this organ, seeing that some of the epithelial processes of the conical papill\u00e6 actually enclose minute hairs in the natural state. (See Todd and Bowman, Anatomy, vol. i. p. 440.)\nt Gazelles, Journal de M\u00e9d. t. xxiv. p. 332.\nj Of more than an inch in length, by Bichat. Anat. Gen. t. iv.\n\u00a7 Ford, Medical Communications, vol. i. p. 444. 1784.\n|| Yet what is to be said of the case related by Henry (Med. Chir. Trans, vol. x. p. 142. 1819) of a middle-aged man, who voided hairs of from of an inch to an inch in length with the urine, some of them occasionally coated with uric acid ?","page":142},{"file":"p0143.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\tJ43\nin, or close to the mouth) without coexistent hairs. Nails and true cutaneous texture are frequently present also. As transition-stages to the purely adventitious formation of teeth appear : the growth of supernumerary teeth in the jaws ; of such teeth not in the jaws, but stiil in the cavity of the mouth ; of such teeth in the neighbourhood of the mouth, as in the orbit,* * * \u00a7 Appearing in the mediastinum -f-, close to the diaphragm in the stomach in the testicle, &c., they are purely adventitious. The ovarian cyst is their chosen seat, however, and their number may be very considerable. In an ovarian cyst now before us (Univ. Coll, Mus.), there are three separate sets of teeth ; in the one are 2 molars, 2 bicuspidati, and 2 canines ; in the second, 2 molars, and 1 incisor ; in the third, 6 molars, 2 bicuspidati, 2 canine, and 1 incisor, \u2014 20 in all. A case has been recorded by Ploucquet and Autenrieth of a young sterile woman, in whom an ovarian cyst contained 300 teeth, \u2014 a fact showing that the relationship (\"contended for by Meckel and others) between the combined number and character of ^adventitious and natural teeth is imaginary.\nThe full consideration of the mode of development and production of adventitious teeth and hair would carry us into the regions of Teratology ; and it must be confessed that the most diligent investigators have failed to find explanations for all cases. If it be true that in some instances these products are the residual parts of a regularly-formed f\u0153tus, in others evidences of an attempt to produce a f\u0153tus (in either of which cases they may be the proceeds either of extra-uterine pregnancy or of the formation of a monster by inclusion), it is also certain, that in other instances all explanations hitherto tendered have failed of their mark.\nCutaneous. \u2014 Except in such cysts as those just referred to, skin is never formed adventitiously. Losses of this texture are repaired by a substance partaking of the characters of induration-matter and of fibrous tissue.\nMucous. \u2014 Portions of mucous membrane destroyed by ulceration are replaced by induration-matter, covered on the free surface with a coating of epithelium, smooth and glistening ; the border is, or is not, puckered and finely nodulated. The attempts made by Sebastian, Dr. Parkes jj, and others, to show that the reparative power goes the length of forming new intestinal mucous texture, the precise anatomical counterpart of the old, appear to us to have failed ; nor is there any evidence that the cicatrix (either of the flat or puckered variety) can even rudely discharge the office of the texture it replaces.\nThe pyogenic membrane of chronic abscesses, tuberculous cavities and fistul\u00e6, has many of the more obvious characteristics of\n* Barnes, Med. Cliir. Trans, vol. iv. p. 316.\nj- Gordon, Med. Chir. Trans, vol. xiii. p. 12. 1825.\nt Berlin, Sammlung, t. iii. p. 264.\n\u00a7 Ruysch, Hist. Anat. Med. dec. in. No. i. p. 2.\n|| On the Dysentery and Hepatitis of India.\nmucous membrane. Of velvety look and feel ; varying (like its prototype) in colour from red to grey, slaty, or even black ; thick as the inner coat of the stomach, or thin as the lining of the frontal sinuses ; more or less closely adherent to a stratum of induration-matter (representing the submucous cellular membrane of health), and covered with epithelium ; capable of producing fungous vegetation from its surface ; and utterly inapt to contract adhesions with itself ; \u2014 this structure has evidently many claims to the title of pseudo-mucous. Its deficiency in villi and follicles simply proves that it imitates the least highly elaborated of nature\u2019s types. The microscopical characters of this formation, however, require full examination.\nGlandular. \u2014 Destroyed glandular texture is not reproduced ; much less does a de novo development of such texture lie within the range of morbid action.\"\nMuscle, \u2014 There is no evidence that striped muscular fibre is produced for purposes of reparation, much less as a wholly adventitious formation.\nUnstriped fibres occurring in the ureter, walls of the gall bladder, and other excretory organs, are rather hypertrophous, than adventitious, products, inasmuch as they naturally exist in minute quantity in those organs. Of the truly adventitious production of this fibre nothing is satisfactorily known.\nSUB-CLASS II,\nGERM-FORMATIONS OR PARASITES.\nProducts, whose continued existence does not depend upon direct access of nutrient fluid from the organism they inhabit ; which spring from a germ*, and simply live in, without forming part of, the individual they infest, are true Parasites. They do not in themselves constitute disease, but always indicate its presence, and sometimes entail its development ; in the latter case they may be made to propagate similar disease from organism to organism. In some rare instances the organic kingdom to which they belong is doubtful ; the great majority easily take their places among animals or vegetables.\nORDER I. \u2014ANIMAL PARASITES.\nSee Entozoa (vol. ii.).\nORDER II.---VEGETABLE PARASITES.\nVegetable parasites form on the skin, on mucous membrane, on new surfaces, upon or within the body, and in certain of the fluids. They indicate the existence (on the surface, or in the fluid, affording them a habitation) of the presence of chemical decomposition, and also of the presence of some new material (albuminous, saccharine, &c.), the result of diseased action. Their precise influence and pathological power in the human subject are yet\n* We set aside the notion of equivocal generation, inasmuch as observation, so far as it goes, deposes to the necessity (at least the existing necessity') of propagation from germs.","page":143},{"file":"p0144.txt","language":"en","ocr_en":"144\tPRODUCTS, ADVENTITIOUS.\nopen to inquiry, but it is certain that the difficulty of killing them obstructs the cure of diseased states (porrigo favosa, for instance), in connection with which they form. They are referrible to fungi and algae, and commonly composed of cells arranged in a moniliform manner, and multiplying by gemmules. When forming on the external surface, they may be called epiphyta ; when within the frame, en-tophyta.\nThe torula has been observed in the urine and in the gastric fluids (Busk) of persons labouring under saccharine diabetes ; also in the faeces, and in vomited fluids under various conditions. Three to five rounded or oval cells, upon which acetic acid produces no appreciable effect, provided sometimes with gemmules (single or more than one),\u2014gemmules differing from themselves simply by being smaller,\u2014the torula of the human subject is in all respects exactly like the torula cerevisiae, and signifies the presence of fer-mentating matters.\nMycodermatous vegetations occur as elements of the crust of porrigo favosa ; they germinate underneath (and never upon) the epidermis in amorphous exudation of protein-basis thrown out by the cutis. Underneath the epidermis, covering the capsule, lies the amorphous exudation-matter in a thin layer ; beneath this, jointed cylindrical tubes, matted together with similar matter; deeper still, fragments of tubes; and yet further, free sporules in abundance : the elongated cells, forming the tubes, occasionally contain molecules,\u2014 these are visible when magnified 800 diameters.* Acetic acid, by lessening the opacity of the amorphous matter, renders the cells and tubes more distinct. Attempts to propagate favus by inoculation of the sporules, the matter of the crust, and the fluid of the pustules, have failed (Gruby, Bennett) ; whether plants, healthy persons, or persons affected with porrigo, have been made the subjects of experiment : failures appearing to show that the parasite is incapable of germinating unless in a special soil (the amorphous exudation-matter), and that the production of this soil constitutes the essence of the disease. Even when the special constitutional state exists, artificial introduction of the sporules will not call forth exudation-matter of the quality fit for their nourishment ; for inoculation'of an affected scalp fails as completely as that of the skin of a healthy person. So, too, the cell of cancer must have its soil of kindred blastema, or the inoculation of its germs will fail. (See p. 124.)\nIn plica polonica Giinsburgf found sporules in the substance of the hair-roots ; Dr. Miinter failed in discovering them,\u2014they are therefore not essential. Gruby detected epiphytes in sycosis between the root of the hair and its sheath.\nSpeaking of entophytic development on\n* H. Bennett in Trans. Roy. Soc. of Edin. vol. xv. part ii. 1842 ; see also Gruby, Comptes Rendus, 1841, 1842, and 1844.\n4 M\u00fcller\u2019s Archiv. 1845. p. 34.\ndiphtheritic exudation of the mucous membranes and skin in a former page (p. 118), the misplacement of a word gives us the appearance of saying that vegetable growth is less common in thrush than in the similar exudation in phthisis, whereas we meant to affirm the contrary.\nDr. Bennett contributes an example of entopytic growth found amid the sputa, and in the contents of cavities, in a case of phthisis : we have ourselves seen jointed vegetable filaments on the walls of cavities.\nIn the fluid of pyrosis Mr. Goodsir* found a living structure closely allied to certain genera of Bacillari\u00e6, but most closely to the genus G onium, among the Volvocinae; looking like a wool-pack (hence the name Sarcina ventriculi), bound with cord, crossing it four times at right angles, and at equal distances ; varying in diameter from -g^ to T\u00f6Vct \u00b0f an inch, and consisting (fig. 99) of sixteen four-\nFig. 99.\nThe Sarcina ventriculi.\ncelled frustules embedded in a square tablet of a transparent texture.\nGROUP II.\nLIQUID ADVENTITIOUS PRODUCTS.\nFluids formed in localities, naturally free from them, are obviously adventitious. Pathologically considered, fluid products are of signal importance ; but the consideration of their morbid anatomy will not long detain us.\nThese fluids accumulate in serous cavities (dropsical) ; in the cellular membrane (oedema or anasarca) ; or in the parenchyma of organs (oedema). They may likewise form in adventitious seats, as in cysts, and in the bullae of erysipelas, rupia and pemphigus, sudamina, &c. When pure, the fluid of dropsy of serous membranes is aqueous, transparent, free from viscidity, and colourless, or faintly yellowish. But it may be thicker, ropy, and of deeper colour, \u2014 and is commonly so in ascitic or ovarian fluid, which has been for any length of time accumulating. Especially in cases of this class, organic corpuscles may be found ; otherwise the flnid is transparent and amorphous under the microscope. In the fluid of syphilitic rupia we have found well-constituted exudation-cells.\nGenerally speaking the fluid of dropsy is alkaline, \u2014 we have never known it otherwise ; but it certainly is occasionally neutral or even acid. In chemical composition it corresponds\n* Edinb. Med. and Surg. Journal, vol. 57. pi. 7 fig. 2.","page":144},{"file":"p0145.txt","language":"en","ocr_en":"PRODUCTS, ADVENTITIOUS.\nvery closely with the serum of the blood,\u2014 its essential protein-ingredient being albumen in the state of albuminate of soda. As various degrees of inspissation of the fluid occur, the ratio of the solid ingredients to the water varies within rather wide limits. Accidental constituents are biliph\u00e6in, urea, and haematin. Fat is always present ; and scales of choles-tein (visible to the naked eye) are not very unfrequent, especially in dropsy of the tunica vaginalis. Epithelial cells are to be seen in small quantities (and we have found these calcified) : there is no reason to believe that an excessive quantity of epithelium is necessarily a part of the disease, though in some cases milkiness or a puriform look may be caused by their extreme abundance. Pus and blood corpuscles may be accidentally present.\nThe fluid of true dropsy is distinguishable by the deficiency of developmental power : it never forms a blastema for cell-growth ; neither is it capable of spontaneous coagulation. But in some rare instances fibrin escapes along with the serum of the blood, \u2014 and this in notable quantity. The fluid then becomes coagulable ; but it is a mystery why (sometimes occurring within the body) its coagulation sometimes does not occur until some hours after its removal from the body. We have seen the contents of the pleura, perfectly fluid when first exposed, become distinctly clotty within an hour and a half : similar occurrences have been witnessed by others. When coagulation takes place within the body, the coagulum may probably act as a blastema. The cause and mechanism of this escape of fibrin from the vessels, and its relationship to inflammation are utterly unknown. In a former place (p. 93) we have spoken of the occasional excretion of fibrin with the urine.\nGROUP hi.\nGASEOUS ADVENTITIOUS PRODUCTS.\nIf the precise signification given to the term Adventitious Product be considered, it will be seen that gaseous matters are only truly adventitious when foreign in nature to the textures producing them. Air entering veins lying within the suction-influence of the chest ; air swallowed; air entering the uterus and bladder from without ; and air diffused through the cellular membrane, serous cavities, or parenchymatous organs, and derived from the air passages or alimentary canal, throngh a wound, ulceration, perforation or rupture of these ; consequently find no place under the present head. We shall here confine ourselves to a notice of gases produced by (a) local or general anti-cadaveric decomposition, and (6) an alleged process of secretion.\n(a) A man, aged twenty-five, died on the sixteenth day of continued fever (Peyerian type), and was examined by M. Bally eight hours after death. The body was soiled with blood, which had transuded through the skin of the thighs and scalp, and there was universal emphysema. The mesenteric glands contained gas which, like that in other parts\nVOL. iv.\n145\nof the body, took fire and exploded, when brought in contact with the flame of a taper ; in burning it formed a tuft with a blue base and white apex, and appears to have consisted of proto-carburet of hydrogen, one of the ordinary products of putrefaction, and is presumed to have been formed before death. (Art. Emphysema, Cyclop\u00e6d. of Surgery, vol. ii. p. 85.) Dr. Mouat (Ed. Med. and Surg. Journal, vol. liii. p. 427. 1840) has published a case in which gas was found in the cellular tissue of the right thigh, on the surface of the pericardium and pia mater, and in the right side of the heart and femoral vein. Accumulation of gas from decomposition of fluid in the pleura, pericardium, peritoneum, joints, and tunica-vaginalis, has been described by various persons : hydropneumothorax, however, it is to be remembered, without perforation of the lung, is certainly of excessive rarity.\n(A) It occasionally happens, as was first, we believe, noticed by Dr. Graves, that at a certain period of the progress of pneumonia, the percussion-signs of pneumothorax may be discovered. Within the last year we have had in our wards a most interesting case of pure and simple pneumonia, unattended with the formation even of dry plastic matter in the pleura, during the progress of which a perfect tympanitic note (quite distinct from an amphoric or tubular one) continued for some time producible over the affected lung. The only mode of accounting for it seemed by admitting the presence of air in the pleura,\n\u2014\tand if such were the fact, that air must have been the produce of secretion. A singular case is recorded by Sir F. Smith*, in which a secretion of gas from the skin appears to have taken place.\n(c) It is not uncommon to find bubbles of gas in the veins of the pia-mater, and their presence is; not easily explicable. If the gas be regarded as of putrefactive origin, the difficulty is to explain why it occurs in bodies perfectly free from ordinary evidence of putrefaction, and why it is limited to those particular veins. If it be regarded as natural gas of the blood extricated during life, how comes it, that the blood in that particular part only should present it after death, and how comes it that, if really extricated there, it had not been carried on with the circulating fluid to the heart? The quantity of gas is too small in such cases to admit of analysis,\n\u2014\telse perhaps a comparison between it and the gases of venous blood might throw some light on the matter.\nBut next comes the curious fact that where there is least blood there is most intra-venous air, \u2014 that is, where there is most of the presumed cause, there is least of the presumed effect. It is, in fact, in persons, who have died from haemorrhage, that air has been found in greatest abundance in the veins. Lieutaudf relates the case of a girl who died\n* Dub. Med. Journal, vol. xviii. p. 457.\nf Hist. Anat. Med. Obs. 55.\nL","page":145},{"file":"p0146.txt","language":"en","ocr_en":"146\tPROSTATE GLAND.\nsuddenly in a state of syncope, after having been repeatedly bled, and in whom the cerebral veins and choroid plexus were found full of air. M. Rerolle* has published several cases of the kind, where profuse haemorrhage had existed ; in one of fatal \u00e9pistaxis, the heart, arteries, and veins, contained large quantities of air. Another of these is rendered particularly remarkable by the fact that the gas (subcutaneous) took fire with slight detonation (as in M. Bally\u2019s case), and burned with a bluish flame ; here the patient had died of haemorrhage after removal of a tumour from the back, and was examined six hours after death, the thermometer (R\u00e9aum.) marking only + 2\u00b0. Similarly Dr. Graves has noticed emphysema of the abdominal parietes in a sufferer from frequent \u00e9pistaxis.\nIn all this there is much mystery. M. Rerolle conjectures that, in such cases, air is absorbed by the radicles of the pulmonary veins, \u2014 the air would then have no claim to be considered adventitious, and the hypothesis is, perhaps, not to be rudely rejected.\n( Walter Hayle Wal&he.')\nPROSTATE GLAND. (Corpus glandu-l\u00f6sum ; Upoardrrjc, Gr. ; die Vorsteherdr\u00fcse, Germ. ; La Prostate, Fr.).\u2014The prostate is a glandular body surrounding the neck of the bladder and beginning of the urethra of the male, deriving its name from its position in front of the vesicul\u00e6 s\u00e9minales. It is situated in the anterior part of the pelvis, behind and below the level oft he symphysis pubis, posterior to the triangular ligament of the urethra, with which it is connected by a continuation of the latter with its capsule. It has the membranous part of the urethra in front of it, and somewhat below its level, and it rests upon the anterior surface of the middle of the rectum. The prostate is perforated by the urethra, two thirds of the gland are below this canal ; it inclines obliquely downwards and forwards from behind, its apex being situated rather below the base.\nIn shape the prostate resembles a Spanish chesnut, or the ace of hearts on playing cards, and presents a base behind and an apex in front ; it is compressed from before backwards ; its sides are convex, and its base is notched. From base to apex the prostate measures from an inch to an inch and a quarter ; from side to side, from an inch and a half to two inches ; and from half an inch to an inch in depth from before backwards : a healthy prostate weighs five or six drachms. This measurement nearly accords with that given by Dupuytren, who devoted much attention to this subject, as having a most important bearing upon the bilateral operation of lithotomy.\nA correct knowledge of the relations of this body to the adjacent viscera is of the highest practical importance. If, after the introduction of a catheter through the urethra into the bladder, the finger be passed into the rectum, * Th\u00e8ses de Paris, No. 129. 1832.\nand carried forward, the bulb of the urethra is first indistinctly felt, behind which is the membranous portion; whilst beyond this, and still within reach of the finger, the prostate is perceived. In the empty state of the bladder the outline of this body is usually distinct enough ; but when the bladder is over distended with urine it becomes in a great measure confounded with the posterior surface of this viscus, and cannot be easily distinguished. To obtain a good view of the connections of the prostate, a side view of the pelvis should\nFig. 100.\na, os pubis ; b, ischium ; c, bladder ; d, ligaments of the prostate ; e, prostate gland ; f, posterior false ligaments of the bladder ; g, ureter ; h, vas deferens ; i, left vesicula seminalis ; j, rectum ; k, a small portion of levatorani.\nbe prepared in the ordinary manner, by the removal of the left os innominatum, with the soft structures in immediate connection with it, leaving a small portion of the symphysis and ramus of the os pubis, together with the spine and a part of the ramus of the ischium. In this manner the levator ani is first brought into view, at the upper edge of which is seen the point of division of the pelvic fascia into the vesical and obturator. The levator ani has no immediate connection with the prostate, for, although it gives it a general lateral support, it is separated from it by the vesical fascia. Internal to the levator ani lie the vesical fascia and the levator prostat\u00e6 muscle. The vesical fascia is continuous with the pelvic, it passes inwards over the prostate, rectum, and bladder, inclosing these structures in separate sheaths. Thus the prostate gets a complete investment from it ; this covering is above continuous with the anterior true ligaments of the bladder, in front it is connected with the posterior layer of the deep perin\u00e6al fascia, and beneath, the fascia passes between the gland and the rectum; thus the gland is completely invested by a fibrous capsule. This envelope incloses within it the prostatic plexus of veins, and the blood-vessels and nerves of the prostate ; the veins are continuous in front with the dorsal","page":146},{"file":"p0147.txt","language":"en","ocr_en":"PROSTATE GLAND.\n\u2022vein of the penis, and behind with branches terminating in the internal iliac vein. Many branches of the prostatic venous plexus are necessarily divided in the lateral operation for the stone ; and in old persons, from their increased size, they occasionally pour out so large a quantity of blood as to endanger the life of the patient. They often contain calculous concretions, to which the term phle-bolithes has been given. The following is the mode of connection between the prostate and the coats of the bladder ; the mucous coat is of course continuous from the bladder to the urethra ; the submucous cellular coat is firmly adherent to the capsule of the gland, whilst the inferior fibres of the detrusor urin\u00e6 are arranged thus, the longitudinal fibres split into two layers, one, the thickest, adheres to the submucous cellular coat of the bladder just behind the prostate; and the other, thin and indistinct, is implanted into the base of the gland itself. Harrison has described a long, delicate, and distinct band of muscular fibres as entering the notch in the base of the gland, beneath the uvula vesic\u00e6 and middle lobe, into which it is sometimes inserted but it can frequently be traced nearly an inch further to be inserted into the veru montanum.* 1 cannot satisfy myself of the existence of any muscular fibres at the under surface of the prostate. On either side of the gland we perceive a muscle, the levator prostates. It is frequently confounded with the anterior edge of the levator ani, from which however it is occasionally separated by a layer of cellular tissue. It arises from the posterior part of the symphysis pubis by a tendinous slip, and its origin extends for a short distance backwards from the anterior true ligament of the bladder of the corresponding side ; as it descends* its fibres spread out over the side of the prostate, and are inserted into the under part of its capsule ; its use is to support the gland, and by compressing it laterally to assist in the evacuation of its ducts. The prostate rests on the anterior surface of the rectum, a thin layer of fascia passing underneath the gland and the vesicul\u00e6 s\u00e9minales. Behind the prostate are the vesicul\u00e6, which diverge from each other as they recede, and are in front received into the interval between the lateral lobes, their anterior extremities are placed beneath, the third lobe ; the vasa defe-rentia run on their inner side, and the common ejaculatory ducts pass upwards in a curved direction, between the lateral and middle lobes, to terminate by the side of the sinus pocu-laris.\t*\nThe anterior surface, which is grooved by a shallow longitudinal depression, is attached to the back part of the symphysis pubis on either side by two ligamentous or tendinous bands, which are continuous with the capsule of the gland below, and above with the true anterior ligaments of the bladder ;\n* See Art. Bladder, vol. i. p. 881. ; \u2019and for description of the arrangement of the circular fibres, see the same article.\n147\nthey are termed the ligamenta pubo-prosta-tica media et lateralia ; they serve to support\nFig. 101.\na, bladder ; b, section of the middle lobe of the prostate ; c, left vas ejaculatorium ; d, left vas deferens.\nthe prostate and sling it to the pubis, thus contributing to the support of the neck of the bladder. The posterior surface of the prostate is smooth and is traversed by a longitudinal depression, at the bottom of which two smaller grooves are visible, inclining towards each other in front, they bound two sides of a small triangular portion of the gland ; this is the under surface of the third lobe, on either side of which a vas ejaculatorium takes its course..\nThe prostate is surrounded by a dense capsule derived from the vesical fascia ; this gives it a complete investment,.and adheres so firmly to the tissue of the gland as to be separated from it with great difficulty. It is divisible into two layers,.between which the prostatic plexus of. veins runs. The gland itself is of a lightish brown colour, of a fleshy feel, and when cut it offers the resistance ot soft cartilage. : it is one of the firmest glands in the body. It is principally formed of two lateral lobes, a right and a left, of equal size in the healthy condition, of an ovoid shape, with their long axes from before backwards ; they diverge from each other behind, leaving an interval between them, already mentioned ; the lateral lobes are connected together beneath the urethra by an isthmus of variable depth and breadth. Between the two lateral lobes, which make up the bulk of the gland, we find the middle or third lobe. The name of Sir Everard Home is usually associated with the description of this lobe. Although not the dis-, coverer of it, he gave the first full description of it. Mr. (now Sir Benjamin) Brodie made dissections of it under Home\u2019s direction ; in the first subject in which it was examined, it appeared as a distinct gland, resembling Cow-per\u2019s gland in size and shape ; but in the examination of this body in five different subjects, the appearance was not the same in any two of them. The following is the account given by Home of what he considers the most natural condition of this part of the prostate ; \u2014 \u201c On turning off' the vasa deferentia and vesicul\u00e6 s\u00e9minales, exactly in the middle of the sulcus, between the tw o lateral portions of the prostate gland, there was a round, pro-","page":147},{"file":"p0148.txt","language":"en","ocr_en":"148\nPROSTATE GLAND.\nminent body, the base of which adhered to the coats of the bladder. It was imbedded not only between the vasa deferentia and the bladder, but also in some measure between the lateral portions of the prostate gland and the bladder, since they were in part spread over it, so as to prevent its circumference from being seen, and they adhered so closely as to require dissection to remove them ; nor could this be done beyond a certain extent, after which the same substance was continued from the one to the other. This proved to be a lobe of the prostate gland ; its middle had a rounded form, united to the gland at the base next the bladder, but rendered a separate lobe by two fissures on its opposite surface. Its ducts passed directly through the coats of the bladder on which it lay, and opened immediately behind the veru montanum.\u201d\nFig. 102.\nA posterior view of the bladder and prostate, with third lobe ; the vasa ejaculatoria and vesiculce are thrown forwards. (From Sir E. Home.) a, ureter ; b, bladder ; c, third lobe of prostate ; d, vas ejaculatorium, turned forwards ; e, vesicula seminalis ; f, vas deferens.\nIt is well known that Hunter was aware of the existence of this lobe as a natural constituent of the prostate, for he says, \u201c A small portion of it (the prostate) which lies behind the very beginning of the urethra, swells forward like a point, as it were, into the bladder ; acting like a valve to the mouth of the urethra, which can be seen even when the swelling is not considerable, by looking on the mouth of the urethra, from the cavity of the bladder in the dead body. It sometimes increases so much, as to form a tumor projecting into the cavity of the bladder some inches.\u201d Hunter has given an accurate draw-\ning of the middle lobe of the prostate. In the normal state it represents a simple elevation of glandular structure beneath the uvula vesic\u00e6, between the two lateral lobes at the back part, and connected laterally with them ; but it varies materially in size and consistence in different subjects. 1 have no doubt that in some cases it is wanting altogether, in others it is of small size; and in many, where it is well developed, it is as firm and consistent as the other parts of the prostate. In one example which I examined, it was much firmer than the lateral lobes, and of a much lighter colour ; indeed, so distinct did it appear that I really doubted whether it belonged to the prostate. I applied a microscopical test, and found its ducts charged with similar concretions to what have been so frequently found in other parts of the gland ; this proved to me that it was a part of the gland itself. The best method of viewing the third lobe is to make a vertical section from before backwards through it, and to carry the incision directly through the veru montanum, sinus pocularis, urethra, and inferior part or isthmus of the prostate, the divided third lobe is thus brought into view, as well as the ejaculatory duct of one side, passing between it and the lateral lobe. The sinus pocularis runs beneath it (see \u25a0fig. 101).\nThe urethra traverses the prostate from behind forwards, and is completely surrounded by it. Amussat doubted this fact, and thought that only three fourths of the canal were encircled by the prostate, and that the remaining fourth (the anterior) was covered by a cellular or muscular medium, extending from one lobe to the other. This is undoubtedly incorrect as a general rule, for 1 have examined with the microscope that portion of the gland placed over the upper surface of the urethra, and found it identical in structure with the remainder of the organ. The urethra in passing through the prostate is dilated into a considerable sinus, and presents in front a triangular opening if a transverse section be made. It is not exactly in the centre, being nearer the anterior than the posterior surface ; it is generally said to be about two lines distant from the former, and four from the latter, and seven from the lateral surface of the gland. It varies frequently in this respect in a marked degree. When the third lobe is small and flat it is much nearer the posterior surface than the anterior ; and this is the case where the isthmus or medium of connection beneath, is thin, a condition not very uncommon. The prostatic portion of the urethra is about fifteen lines in length, and is wider in the middle than at either extremity ; it contains within it the veru montanum or caput gallinaginis, which runs along it, forming a conical elevation, and dividing it into two equal portions.\nOver the urethral surface of the third or middle lobe of the prostate, the mucous membrane is raised up so as in some subjects to form a remarkable elevation, lying transversely at the beginning of the urethra ; this","page":148},{"file":"p0149.txt","language":"en","ocr_en":"149\nPROSTATE GLAND.\nis especially seen in old subjects : it corresponds with the anterior extremity of the\nFig. 103.\nFront view of the bladder and prostate.\na, bladder ; b, ureters ; c, uvula vesic\u00e6 ; d, prostate gland ; e, openings of prostatic ducts ; f, a probe passed into the sinus pocularis ; g, g, bristles in vasa ejaculatorium ; h, membraneous portion of urethra.\ntrigonum vesic\u00e6, and is known by the names of the uvula vesic\u00e6, luette v\u00e9sicale, val vida pylorica of Amussat. In the healthy state of the bladder and prostate, this elevation is frequently scarcely perceptible, unless the bladder is much contracted ; but it is subject to considerable increase in size, and is generally involved in those cases of enlarged prostate which are of such frequent occurrence in the old person, and where the third lobe is the seat of hypertrophy. Mercier describes this vesico-nrethral valve as a semicircular fold, raised suddenly at a right angle from the posterior surface of the neck of the bladder, and composed of a tissue somewhat resembling muscle ; and Mr. Guthrie, in his lectures delivered at the College of Surgeons in the year 1830, directed attention to it as frequently the seat of disease totally independent of any enlargement of the third lobe of the prostate ; but to this I shall again direct attention when the morbid anatomy of the prostate is under consideration.\nIntimate Structure. \u2014 The prostate comes under that division of the glandular system, inappropriately termed conglomerate. Midler\nplaces it in his fourth order of glands\u2014liglan-dul\u00e6 ex cellulorum contextu spongioso composit\u00e6, mediis cellulis in ductus excretorios hiantibus, sine lobulorum divisione composite.\u201d It is arranged by Cuvier under the head of supplementary glands of the male organs of generation. The external covering of the gland, derived, as already described, from the vesical fascia, having been removed, we come to a deeper layer, which closely surrounds the glandular tissue; it is most intimately connected with it, so as to be detached with the greatest possible difficulty, and can evidently be shown to send processes into the gland, which are probably continuous with the fibrous tissue between the follicles. On the surface of this the lymphatics of the gland are seen to ramify : this is best shown after previous immersion in water. If a simple section is made, the gland presents a spongy cellular aspect, and an opaque fluid oozes out from the cut surface ; but its intimate structure can only be made out by microscopical examination of thin sections, or by injections with mercury or coloured size, or by inflation ; the outline of its follicles may, however, be seen by a minute injection of its blood vessels, which ramify in a delicate plexiform manner on their surface. It is not a gland of much complexity of structure or arrangement. Briefly, it may be said to be composed of minute terminal follicles, opening into canals or tubes, which unite together to form ducts, which open in an oblique manner on the prostatic portion of the urethra. The orifices of the prostatic ducts are situated principally close to and around the most elevated portion of the veru montanum, in the form of a crescent, the larger ducts on the side, and the smaller on the posterior aspect of this body If a longitudinal, vertical section is made, many of the ducts of the prostate are seen passing upwards, towards the under part of the veru montanum, in a straight direction ; the interior of some of them being slit open in the section, whilst others pass obliquely beneath the mucous membrane for some distance prior to their termination. They vary in number from ten to fourteen, but as many as thirty have been seen. Their diameter ranges from one-sixth to one-fourth of a line. It sometimes happens that two or more ducts unite, and open by one common orifice, large enough to aflmit the end of a small probe.\nTo unravel the structure of the gland, it is requisite to inject the ducts separately, as the follicles to which they lead have no communication with each other, as the representation given by M\u00fcller would lead one to imagine ; each duct will be found to give off\u2019 tubes, which passing in a straight direction, separate gradually from each other, and terminate in minute cells or follicles, which, according to Weber, range from one-sixteenth to one-twelfth of a line in diameter. M\u00fcller says that the larger cells are visible to the naked eye, and that with a simple microscope the smaller cells, situated within the larger, and formed of an exceedingly delicate membrane\nL 3","page":149},{"file":"p0150.txt","language":"en","ocr_en":"150\tPROSTATE GLAND.\ncan be seen ; the cellular structure is rendered perceptible by inflation from the ducts. Mr. John Quekett has injected with coloured size, and examined the tubes and follicles of the prostate with the microscope, and represents the latter as varying in size in different parts of the gland ; he thinks that one-hundredth of an inch is their average diameter, and has delineated them as is shown in fig. 104. Henle\nFig. 104.\n\nhas found them to be lined by a delicate pavement epithelium, and at the commencement of the duct he has seen a cylindrical epithelium. Mr. Quekett has traced an intermediate cellular or fibrous tissue, filling up the spaces between the follicles or lobules., and connecting them together. According to Dr. G. H. Jones, \u201c this principally consists of the white fibrous element, but also contains numerous bands, resembling closely those of organic muscle.\u201d * The latter anatomist thinks that the enlargement of the gland in hypertrophy of the prostate, is due to an increase in this tissue : he regards the prostate as an assemblage of secerning follicles rather than as a really conglomerate gland.\nThe arteries of the prostate are usually derived from the vesical and h\u00e6morrhoidal branches of the internal pudic, and from the middle h\u00e6morrhoidal of the internal iliac, which, entering the gland on either side beneath its capsule, are distributed in the form of a network on the parietes of its tubes and follicles; the veins terminate in the vesical and h\u00e6morrhoidal veins : its nerves, which are extremely small, are branches of the hypogastric plexus of the great sympathetic. The lymphatics consist of a superficial and deep set, and pass into the hypogastric ganglia. It happens occasionally that an artery of considerable magnitude run-s on either side of the prostate, from the internal iliac, and becomes the artery of the bulb of the urethra. This variety has been seen by Haller, Burns, and Barclay. I have witnessed a similar distribution myself. Dr. Monro met with a case, in which an irregular vessel came from the internal iliac, passed along the lateral and inferior surface of the bladder, pierced the ilio-vesical fascia, ran along the lateral lobe of the prostate, and divided into three branches, one to the dorsum, one to the crus penis, and another to the bulb. Other varieties in the course and distribution of the branches of the internal iliac, involving the prostate, have been occasionally met with, and I allude to\nthem here as points of great interest in respect to the surgical anatomy of this body.\nLiquor Prostaticus. \u2014 It is the office of the prostate to eliminate from the blood sent into its arteries a fluid called the liquor prostaticus. This has been examined microscopically; but in consequence of the difficulty in obtaining it in any large quantity, it has not hitherto been made the subject of chemical, analysis. This fluid can be obtained after death by-squeezing the gland, when it oozes through the orifices of the ducts around the veru montanum. It usually presents a turbid appearance, is of a thin milky aspect, and is \u00abomewhat unctuous to the feel. Haller found it in many cases coagulable by the addition of alcohol ; it contains, according to Krause, muddy flakes, or globules, filled with minute granules, varying from to 300 a ^ne diameter. Pr\u00e9vost and Dumas examined the liquor prostaticus of the dog, cat, hedgehog, and rabbit : they found it to contain globules like milk-globules. Cuvier remarked in the fluid of the hedgehog, numerous ovoid and spherical vesicles, others oblong and conical in shape : many of the vesicles presented a stellate aspect, and contained a central nucleus. I have carefully examined, in many cases, the prostatic secretion of the human subject, in as fresh a state as I could possibly procure it. I have found it of a milky aspect, like a very weak mixture of milk with water. In some cases, I have seen it of a consistence more resembling cream. I consider the former state to represent the healthy fluid. Examined with the microscope, it was found to contain numerous molecules, epithelial cells, both pavement and cylindrical, in various stages of formation, and granular nuclei of about 0-0036 of a line in diameter. In by far the greater number of instances in which I have examined it, I have been rather surprised to find it give feeble but distinct signs of acidity when tested by litmus paper. I thought it not unlikely that the apparent acidity of the prostatic secretion was due to the cadaveric infiltration of urine through the tissue of the gland ; but I adopted every precaution, by carefully and repeatedly washing the surface of the bladder and urethra, to obviate this source of fallacy, and the result was still the same. I have found a similar reaction in the prostatic secretion of an old man, in whom the gland was greatly hypertrophied ; and where the ducts and follicles w\u00e6re distended with an opaque creamy-looking fluid, such as is often seen after death. The appearance of the liquor prostaticus may be, and probably is, very different after death to what it is during life. There is every reason to believe that it is secreted more clear and transparent, and it most likely owes much of its turbid appearance to the admixture of a large number of minute epithelial cells. I regret that I have nothing to offer as to its chemical constituents, as it is not possible to collect more than two or three drops at a time, a quantity too small to submit to chemical investigation. That the acidity of the\nMedical Gazette, Aug. 20. 1847.","page":150},{"file":"p0151.txt","language":"en","ocr_en":"151\nPROSTATE GLAND.\nliquor prostaticus is not incompatible with the existence of calculous concretions of the phosphatic species in the follicles of the gland, I have proved by repeated examination.\nUtriculus prostaticus. Vesicala spermatica spuria. Vesica prostatica. Sinus pocularis. \u2014 At the anterior part of the most elevated portion of the veru montanum, we find an opening in the mesial line one-third or half a line broad, leading backwards to a small bag resembling a bottle in figure, of variable length and breadth: it is generally known by the name of the sinus pocularis, but has received\nFig. 105.\na, bladder ; b, middle lobe of prostate ; c, view of the left side of the utriculus prostaticus ; d, bristle in left vas ejaculatorium.\nalso the designations here mentioned. In most cases in wrhich I have examined it, it forms a canal, terminating in a blind extremity, and usually is not more than three or four lines long. I have found it an inch in length. The opening, which faces obliquely forwards, will just admit the point of a small catheter or bougie. Some surgical interest is attached to this structure, because it has been stated by writers on urethral diseases that an instrument is liable to catch in it when an attempt is made to pass it into the bladder ; but I believe this very rarely happens, as the beak of the catheter is usually kept against the anterior surface of the urethra, when it is made to traverse the prostatic portion, and it is therefore carried well above this little pouch i if, however, such an accident should be suspected to have occurred, a gentle withdrawal of the instrument and depression of the handle are quite sufficient to clear the impediment referred to. But much physiological importance attaches to this sinus, for reasons which we shall presently see, Husehke describes it in the following manner : \u2014 It commences by a narrow portion, resembling a neck, which forms about half its length, behind which it swells out into a round membranous vesicle or fundus ; between these two portions there is often a constriction. It penetrates the posterior surface of the prostate gland, so that the middle lobe is situated in front of its fundus. Its parietes are thinner at the fundus than at the neck, and are usually about one-fourth of a line in thickness. On either side a vas ejaculatorium is inclosed within its wall ; so that, in point of fact, these ducts do not penetrate the glandular substance of the prostate. Its walls are composed of two layers, an external, fibrous\nand strong ; an internal, of a mucous character : the latter is covered by small mucous glands, arranged closely together, with openings of about the twenty-fifth of a line in diameter. These glands resemble minute warts, each w ith a small opening on its apex. They cannot be confounded with the orifices of the prostatic ducts, as these always open external to this pouch, around the veru montanum. About its neck larger glandular openings are perceptible. The nature of the secretion of these glands is not known.\nGreat physiological interest attaches to the utriculus, from its having been supposed by anatomists to be the true representative of the uterus. Its homology with this body is evinced by its shape, and position between the two ejaculatory ducts, although the latter do not open into it, as the fallopian tubes do into the uterus ; thus it resembles the latter body by its division into a neck and fundus, by its being surrounded by the prostatic ducts, as the uterus is at its orifice by the follicles there situated, and by the veru montanum forming to its orifice a prolonged inferior labium ; and if, as some anatomists assert, the ejaculatory ducts occasionally open directly into the pouch, or previously unite together, the parallel is infinitely more perfect.\nMorgagni has given a description and figure of the utriculus as he found it in five subjects which he examined. Ackerman also described it, and termed it uterus cystoides, and mentions instances described by Petit, Sue, and Mar et, where it was an inch in extent. In one case mentioned by himself, it was actually larger than the prostate gland. E. H. Weber pointed out its physiological interest as a rudimentary uterus, and Husehke, has found it filled with a yellowish liquid, in which he distinctly recognised portions of cylindrical epithelium.* The best description I can find of this structure, is that by Husehke who examined it in the hare. He found it in this animal in the form of a bottle, fifteen lines in length and half an inch in breadth, extending behind the bladder. It commenced by a simple transverse fissure, from a line to a line and a half in breadth, over the veru montanum. It gradually dilated for about half an inch, and becoming contracted, it was again dilated, and terminated in a point rather to the left side. The vasa deferentia were situated by the side of the utriculus, and gradually approximating, they opened within a line of each other in the utriculus, at about a line and a half or two lines from its orifice, by two large papillary openings ; so that when air was injected by one vas deferens, it not only escaped from the opening of the utriculus, but filled its cavity, and passed into the other. Husehke supposes that the utriculus in this animal always contains semen, as the existence of spermatozoa, and the appearance of the fluid indicate. In an anatomical point of view, he does not consider it at all analogous\n* See note to \u201c Husehke, in Encyclop\u00e9die Anatomique traduit de l\u2019Allemand par A. J. L. Jourdan.\u201d\nb 4","page":151},{"file":"p0152.txt","language":"en","ocr_en":"152\tPROSTATE GLAND.\nto the vesicul\u00e6 s\u00e9minales of man ; but in the hare as an uterus for the reception of semen, as the female uterus receives the ovule. A more minute examination of this bag strengthens this conviction. Its orifice is transverse, and represents an os tincae in the arrangement of its labia ; 2dly, there is an evident distinction in the mucous lining of its neck and fundus, it being arranged in five or six longitudinal folds, so as to form a true arbor vitae, and seems covered with muscular fibres. The following are the deductions of Huschke :\u20141st, That the utriculus is a male uterus; 2dly, that it is originally a receptacle of seminal fluid ; 3dly, that its development is in. the inverse ratio of the development of the vesicul\u00e6 s\u00e9minales and prostate gland in man ; 4thlv, that it is a vestige of a structure existing in the foetus, and in man is really of no use whatever.\nCuvier has described a long membranous canal with a spherical extremity, situated between the two vasa deferentia in the solipeds. This long bag opens on to the urethra, in front of the common orifices of the vasa deferentia and vesicul\u00e6 s\u00e9minales, rather to the left side. A fluid of the consistency of honey can be squeezed out of it. This is evidently the utriculus.\nIn an interesting case of hypospadias, a case peculiarly favourable for the investigation, Professor Theile, of Berne, most carefully examined the utriculus, and described its anatomical relations. I take the following account of this examination from the first number of the \u201c British and Foreign Medico-Chirurgical Review:\u201d \u2014 \u201c The scrotum contained two testicles.; the vasa deferentia, vesicul\u00e6 s\u00e9minales, and prostate gland were present. The latter was fourteen lines long, eight and a- half thick, and sixteen broad. Theile found a canal originating in the usual opening on the utriculus, run backwards for an inch and a half, ending in a cul-de-sac four lines in diameter, and placed between the two vasa deferentia ; this canal (.vesica prostatica), with the exception of its anterior part, did not lie within the prostate, but below or behind this gland. Besides this structure, a small, oval, glandular body, five lines long, four broad, and two thick, was found behind, lying between the vesica prostatica and the prostate itself ; it did not appear that this substance was continuous with the substance of the prostate, although this continuity might have existed and escaped detection. Examined by the microscope, this body presented an aggregation of cells and vesicles, which were much more easily seen in it than in the proper prostate. Theile regards this body, lying closely upon the vesica prostatica, as a middle lobe of the prostate. In order to ascertain the relation of the ductus ejaculatorius with the vesicle, a wax injection was thrown into the lower part of the vas deferens. On a careful examination, it was found that the ejaculatory duct did not open into the utriculus, but was only closely applied to its lateral wall, and then penetrated into the urethra in the usual\nplace.\u201d In this case the membranous portion of the urethra opened into a normal bulbous portion.\nProfessor Theile also gives an account of another case of hypospadias, \u201c dissected by\nFig. 106.\ne, utriculus prostaticus, from M\u00fcller\u2019s Archiv.\nthe elder S\u0153mmerring, in which the urethra and scrotum were fissured, the testicles remaining in the abdomen. Between the glands and the anus two openings were found, separated by a partition of about one line in breadth. That next the penis was the orifice of the urethra ; the latter led into a canal, into which a quill could be passed. It was an inch and a half long, and when inflated it was nearly as large as the little finger, and was situated between the bladder and rectum, but nearer to the former. S\u0153mmerring laid open the canal towards the rectum, and it appeared like * an alveus communis,\u2019 into which the vesicul\u00e6 s\u00e9minales opened. When quicksilver was injected into the vasa deferentia, it ran partly into the vesicul\u00e6 s\u00e9minales, but partly into this pouch.\u201d \u201c The existence in the male of a central sac or canal, occupying \u2018precisely the same relation to the orificium urethrae, the bladder, and the rectum, as the vagina in the female, is particularly elucidative ; and, among other facts, for which we are indebted to em-bryological research, further corroborates the conclusion of the most scientific anatomists of the present day, that every variety of so-called hermaphroditical malformation is referrible to an abnormal condition, either of the male or of the female organs, existing singly, and but rarely conjoined in the same individual.\u201d","page":152},{"file":"p0153.txt","language":"en","ocr_en":"PROSTATE GLAND.\t153\nWith these facts before us, there is no necessity to resort to the mechanical idea of the gradual distension of the prostate gland and vesicul\u00e6 s\u00e9minales to account for the existence of a rudimentary uterus in those cases of hermaphrodism where the subject is unquestionably male, with an increase in the development of the utriculus beyond its natural condition. I would also venture to suggest, that what Mr. Hunter has delineated as the uterus, in the representation he has given of the dissection \u201c of Mr. Wright\u2019s free-martin, which are more the parts of a bull than those of a cow,\u201d is really a preter-naturally large utriculus prostaticus. I have given a side view of the interior of the utriculus, in a case which I examined myself ; in this instance it extended obliquely downwards and backwards, beneath the third lobe of the prostate, for the distance of about half an inch, and was slightly enlarged at its fundus. (See Jig. 104.)\nThe development of the prostate and vesicula prostatica.\u2014There is no department of em-bryological research of higher interest than that relating to the development of the genito-urinary system. A minute inquiry into this subject, and a careful observation of the phenomena attending it, can afford the only means of obtaining a satisfactory clue to the comprehension of that remarkable structure just described. By no other means is it possible to ascertain the natural relation of the utriculus prostaticus.\nI shall limit the inquiry here to the manner in which the utriculus and prostate gland are supposed to be formed.\nAt an early period of foetal existence the allantoid sac, which was continuous with the urinary bladder, becomes shut off entirely from that viscus, and the only remains of its original communication is the obliterated urachus. As the bladder at its inferior fundus communicates with the intestine, thus forming with it one common cavity, it may fairly be said that the human subject really is at this period possessed of a cloaca. In the mammiferous class generally the urinary bladder very soon separates from the intestine, and has a separate opening externally in front of the anal aperture. There are different opinions as to how this is actually accomplished ; but there is no necessity to discuss the question here. In this separation of the bladder from the rectum, the evidence of the existence of a cloaca disappears, and a cavity, or space, or canal is left common to the bladder and genital organs ; this is termed the sinus uro-geni-talis, or the canalis uro-genitalis. This afterwards, in the male, is represented by the neck of the bladder and beginning of the urethra, and communicates with the external organs. In the monotremata the uro-genital canal is persistent. The sinus uro-genitalis receives the terminations of the excretory ducts of the Woolfian bodies, the ureters, the vasa defe-rentia in the male, and the fallopian tubes in the female. In the female the vagina and uterus are both developed by extension and\ndivision of this canal,\u2014the vagina having in front of it the urethra ; and as development advances, the last portion of the sinus uro-genitalis is represented by the vestibulum, and is common to the urethra and the vagina. According to Valentin, in the male the vasa defe-rentia at first open together in the mesial portion of the uro-genital canal ; in the female the same is observed in respect to the fallopian tubes. Rathke states that at a later period a small conical crimpling of the uro-genital sinus occurs near the openings of the vasa deferentia, and that from this the vesicul\u00e6 s\u00e9minales are developed, which communicate with the vasa deferentia, and, indirectly, with the sinus, or with the urethra itself. A separation takes place between the two vasa deferentia, when each vas deferens, uniting with a corresponding vesicule, opens separately into the urethra. In the interval between the terminations of the vasa deferentia we find the remains of the uro-genital sinus, which eventually becomes the utriculus, or ve-sicula prostatica, or sinus pocularis.\nBischoff thinks that the prostate gland commences by a simple thickening of the vasa deferentia near their termination. It is most probably further developed in the same manner as the glandular system generally. He agrees with Rathke in the opinion that there exists a septum between the two sides at this portion of the urethra, the vestiges of which are represented by the veru montanum.\nTo complete the analogy between the utriculus and the female uterus, the vasa ejacu-latoria ought to terminate beneath, or rather within the utriculus, as the fallopian tubes do in the uterus ; and this is said really to happen occasionally. Morgagni mentions two instances of this. I have found it myself, but it is rare ; yet the fact of even its occurrence now and then adds all we require to complete the evidence in favour of the analogy between these two apparently dissimilar structures. Presuming all that has been stated to be true, we need not tax our ingenuity further, in endeavouring to assign a use to this heretofore obscure structure the sinus pocularis.\nThe prostate, up to the period of the full development of the organs of generation, is of small size. In the early periods of foetal existence it is composed of two lateral lobes, which coalescing at the fourth or fifth month, give rise to the isthmus and third lobe.* It is rounder in the child, is situated vertically, and is said to be occasionally just reached by the peritonaeum. As we advance in life it becomes firmer in texture and yellowish in colour. Mercier says that in the child the anterior part of the gland exceeds the posterior in thickness ; in other words, that the prostatic ring encircling the urethra is thicker above than below.\nFunction of the prostrate gland. \u25a0\u2014 It is the office of the prostate to secrete a bland and\n* I do not consider the isthmus and third lobe as synonymous expressions, and would limit the former term to that portion of the gland which connects the lateral lobes beneath the urethra.","page":153},{"file":"p0154.txt","language":"en","ocr_en":"154\tPHOSTATE GLAND.\nsomewhat viscid fluid, which is poured into the urethra at the commencement of its course, at that point where the secretion of the testes and vesicul\u00e6 s\u00e9minales are received into the canal. It is well known that the secretion of the prostate is increased in quantity under states of venereal excitement ; I have, however, some doubts as to whether the secretion effused under such circumstances is wholly prostatic : I cannot help thinking that some of it at least is due to the glands of Cowper and the follicles of the urethra generally ; but, be this as it may, there can be no doubt that the largest quantity of the prostatic fluid is poured into the urethra at the moment of, or prior to, the venereal orgasm ; at least we are justified in drawing this inference from observations made on these parts in animals killed during, or immediately after, the completion of the act of copulation.\nThat the prostatic fluid is subservient to the generative function, may be deduced from these circumstances ; and this is further established by the fact mentioned by Hunter, that the gland is liable to changes at certain seasons, and that in the mole, in winter, the prostate is scarcely discernible, whilst in the spring it becomes of large size, and filled with fluid. We are not aware whether this is the case universally in the animal kingdom. How does the prostatic fluid aid the function of generation ?\nAn old opinion assigns to these accessory glands the office of perfecting and increasing the bulk of the seminal secretion, so that the urethra may be more fully distended by it, and its muscles may be enabled to act more completely in forcibly injecting its contents into the vagina. This idea is, in my mind, rather too mechanical, although it may be advanced in its favour, that these accessory glands are found in all animals, where they exist, to empty themselves into those dilated portions of the urethra, in which the seminal secretion is supposed to accumulate prior to its expulsion. It has been thought by some that the prostatic secretion is useful in diluting the semen, so as to increase its bulk, not merely for the more perfect distension of the urethra, but that it may ensure the more easy transmission of this secretion into the female vagina, and thus favour its contact with, and impregnation of, the ovum. As to its defending the orifices of the ejaculatory ducts from the presumed acrimony of the urine, I cannot attach any importance whatever to this notion ; the gland is essentially a sexual organ, and its use must, in some manner or another, be connected with the excretion of the seminal fluid, either in the manner just mentioned, or in lubricating the surface of the urethra, so as to facilitate the onward passage of this fluid. The very structure of the prostate, which is of the simple follicular character, favours the latter notion. Its position at the commencement of the urethra leads to the same conclusion. It is probable that its secretion is poured into the urethra prior to the escape of the seminal fluid into the canal ; and it is quite evident that no large glandular masses\ncould have been conveniently placed along the urethra in any other situation; for however much they vary in number and size, in the various orders of animals, their position near the beginning of the urethra is constant.\nThe prostate gland, with Cowper\u2019s glands and the vesicul\u00e6 s\u00e9minales, must be regarded as accessory rather than as organs essential to the generative function. That it is not essential in man, is rendered probable by the persistence of the procreative faculty in many cases of extensive disease of this organ.\nIn connection with this obscure and difficult subject, I think the fact of the prostatic secretion being naturally, as I believe, acid, is a circumstance of some interest. The secretion of the testes is well known to be alkaline, and has a strong tendency to coagulate or become inspissated. Is it not probable that the reaction of the prostatic on the seminal fluid may be of use in the maintenance of the fluidity of the latter ? The idea is somewhat confirmed by the fact, that in women the acid secretion of the vagina prevents the coagulation of the menstrual blood, and thus favours its discharge. This has been proved by Mr. Whitehead, who found that, if the menstrual fluid was received directly from the os uteri into a speculum, it coagulated like ordinary blood.*\nMorbid Anatomy. \u2014 Hypertrophy. \u2014 In advancing years, when all other structures in the body begin to show evidence of a failing nutrition, and are atrophied or wasted by interstitial absorption, the prostate gland, on the contrary, very frequently becomes the subject of a remarkable increase in size. This is so common after the age of fifty, that an enlarged prostate may be almost regarded as one of the necessary contingencies of advanced age. It is not, however, exclusively in the old person that this takes place ; it sometimes happens at a much earlier period of life ; nay, a case is mentioned by Sir Astley Cooper of a boy whose prostate was found, on dissection, of very large size ; but it is not improbable that this remarkable enlargement depended on strumous deposit in the gland. In considering this subject, it is important to distinguish between this affection of the prostate and the simple engorgement consequent on acute or chronic inflammation ; these latter conditions occur more frequently between twenty and forty years of age, and depend on stricture of the urethra, or the mal-treatment of severe gonorrhoea.\nHypertrophy of the prostate is so insidious in its mode of invasion,thattheonlyindications of its occurrence are evinced by the mechanical impediment to the free discharge of the urine, in consequence of the increased size of the gland. No pain, no uneasiness is felt before the prostate has obtained a considerable volume, after which, symptoms of a most distressing character set in, and continue, with more or less severity, to the termination of\n* On the Causes of Abortion and Sterility, &c., by James Whitehead, 1847. t","page":154},{"file":"p0155.txt","language":"en","ocr_en":"PROSTATE GLAND.\n155\nthe patient\u2019s existence. It would be out of place here to enter into the signs which characterise the progress of this disease. I must confine my observations to the state of the gland itself, to the effect produced upon the adjacent structures by its enlargement, and to its cause.\nIn senile hypertrophy, the gland becomes enlarged in all its dimensions ; it expands laterally, extends downwards towards the rectum, so as to be readily felt, forming a considerable tumour in this situation, and upwards behind the symphysis pubis, so that in a thin person, with the hand firmly pressed upon the hypogastric region, the surgeon can, in some cases, feel it distinctly. Its outer surface is smooth and round, or occasionally irregular and nodulated : the two lateral lobes expanding universally, are pressed together, so as to become flattened at their opposed surfaces ; if one increases particularly at one part, as is often the case, there is a corresponding indentation in the other, and thus the direct course of the urethra is altered, and the canal is twisted in various directions. The disease is not usually confined to its lateral lobes ; for the third lobe frequently participates in the enlargement. This may happen to a great extent, in some measure, independently of the increase in size of the lateral lobes ; but usually, where the middle lobe is affected, the lateral lobes are enlarged, although the converse of this condition is not so invariable. The middle lobe sometimes forms a simple pyramidal elevation at the urethral orifice ; sometimes a large pendulous or valvular tumour, occasionally rising upwards from the posterior part of the prostate in the mesial line direct, frequently inclining to one side. It has been known to attain the size of a small orange ; and where it has increased to such an extent, it must of necessity happen that the base of the tumour is the smallest part of it. Whatever form of enlargement the middle lobe assumes, the tumour always projects towards the bladder: it is frequently knotty or lobulated on the surface. In its increase, the third lobe draws up the prostatic portion of the urethra, and elongates the veru montanum. Very great interest has attached to this condition of the middle lobe, in a surgical point of view, since Sir Everard Home particularly directed the attention of surgeons to Mr. Hunter\u2019s observations upon it, who states \u201c that it sometimes increases so much, as to form a tumour projecting into the cavity of the bladder some inches.\u201d The disease of this part of the gland had not escaped the observation of Morgagni, although he did not attach much importance to it : it was also known to Valsalva.\nHypertrophy of the prostate is frequently attended with general induration, so that when cut into, it almost resembles cartilage. This has obviously given rise to the term scirrhous prostate, as applied by the older surgeons to the disease in question. In other instances, it feels softer than natural. The capsule becomes gradually attenuated by distension, and\nthe direction of the tumour is always towards the part where there is least resistance.\nIt has been very commonly asserted that the left lobe is more frequently hypertrophied than the right. The observation originated with Sir Everard Home. I cannot deny the truth of the assertion; but it is divested of any practical importance, as it is well known that the right lobe is in very many cases the larger of the two. However, the fact that the two are very frequently unequally enlarged, ought to be impressed upon the mind of the surgeon, as he may expect that the course of the urethra will deviate to either side, and (in the introduction of the catheter) in cases of retention, from enlarged prostate, he must direct his instrument accordingly.\nThe enormous increase of size which the prostate attains, produces serious inconvenience to the parts adjacent. Thus, independent of the effect on the nerves of the pelvis, as indicated by pains in the loins, sacrum, groins, and down the thighs, its influence is most sensibly perceived in the altered state of the urethra, in the bladder, and the rectum. By the enlargement of the prostate, the urethra is increased in length \u2014 a fact well known to practical surgeons. This actual elongation takes place only in the prostatic portion of the canal ; the diameter of the urethra, so far from being diminished, is really increased ; but the part surrounded by the gland is altered in shape ; for, whereas in the natural state the prostatic sinus is longer in a transverse than in a vertical direction, it is now quite the reverse : its sides are also approximated by the coaptation of the lateral lobes ; and if any unequal projection of either lobe exists, it takes a tortuous course to reach the bladder, or reaches it by two channels, one on each side of the middle lobe ; besides which, the urethral orifice into the bladder is more or less blocked up by the projection of the middle lobe, or is raised higher than natural, the prostatic part of the canal forming a sickle-like curve, the convexity of which is downwards. The prostatic sinus is occasionally dilated to such an extent, as to be capable of holding two ounces or more of urine. The veru montanum is placed at a greater distance than natural from the bladder. The bladder becomes either preternaturally dilated, or contracted to a very small size; these two opposite conditions probably depending on the greater or less irritability of the viscus ; sometimes it is sacculated ; its muscular coat is thickened, and its mucous lining becomes the seat of acute or chronic inflammation, with all its accompanying pathological changes. So also the ureter and even the kidneys themselves are frequently diseased in the advanced stages of this affection. When the third lobe is much enlarged, it throws the neck of the bladder forwards, and increases the depth oftheinferior fundus to such a degree, as to cause the lodgment of calculi in its cavity. In one respect, this circumstance is attended with some advantage, inasmuch as it lulls the symptoms of stone, by preventing","page":155},{"file":"p0156.txt","language":"en","ocr_en":"156\tPROSTATE GLAND.\nthe calculus from coming in contact with the sensitive neck of the bladder. But an obvious inconvenience arises in other cases from the difficulty of seizing calculi under such circumstances, in the operation of lithotrity ; and after a calculus is broken up, it prevents the escape of the fragments, and thus favours the recurrence of the disease.\nIts influence on the rectum is felt in the flattening of its cavity from before backwards, and by its projection it causes the rectum to rise up on either side of it. Haemorrhoids and prolapsus ani are by no means unfrequent attendants on enlargement of the prostate.\nOn examining with the microscope sections of an hypertrophied prostate with Mr. Quekett, I found numerous crystals in its ducts, which disappeared on adding dilute muriatic acid.\nAtrophy. \u2014 The prostate is liable to atrophy, but the disease is rare. I have met with it myself occasionally in very old persons. When the gland is altogether diminished in size it is usually more consolidated in its texture. It is, however, liable to another form of atrophy (eccentric atrophy), by which I mean a thinning of its tissue generally, and its conversion into one or more cysts, in consequence of continued pressure exerted by the increase in size of calculous concretions in its follicles. \u201c Cases sometimes occur, in which the whole of one lobe, or even the entire organ, is converted into a thin fibrous capsule, the proper substance of the gland being almost wasted.\u201d\u2014(Crosse\u2019s Pathology.) In those cases the ducts of the prostate are usually increased in size, so as to arrest the progress of the catheter. It generally occurs in connection with urinary calculi, or long-standing stricture. Dr.Baillie met with one instance of atrophied prostate ; it occurred in a case of ectropium of the urinary bladder, and malformation of the organs of generation ; the utriculus pros-taticus was larger than natural.\nInflammation. \u2014 Inflammation, acute or chronic, not unfrequently attacks the prostate, leading to increase of size, and suppuration of the gland. It is very commonly the result of suppressed gonorrhoeal discharge, and follows the employment of copaiba, cubebs, and powerfully stimulating injections. The signs of this condition are easily understood. With careful and somewhat active treatment by leeches, cupping in the perin\u00e6um, warm fomentations, &c., the disease terminates in resolution ; but permanent enlargement or suppuration are the too frequent consequences of inflamed prostate. An irritable state, characterised by an uneasy sensation referred usually to the end of the penis, and attended by an increase in the secretion of the gland, which can be drawn out in threads, with a frequent desire ofmaking water, indicates an inflamed condition of the prostatic ducts. The discharge is occasionally puriform in appearance.\nAbscess. \u2014 If the inflammation be unsubdued, suppuration often occurs. The whole tissue of the gland is, in some instances, infiltrated with pus ; in others a single abscess, of large size, or numerous small abscesses\noccupy one or both lobes of the prostate. Sir Benjamin Brodie relates an instance of an old man, the subject of abscess of the prostate, containing at least half a pint of pus, which escaped through the catheter, after the urine had been drawn off. Many similar instances are recorded. These large collections are generally the result of an attack of acute inflammation on an already enlarged prostate. Smaller purulent deposits are met with in various parts of the gland ; so that when after death the pus is washed away, the prostate is found riddled with holes. Such deposits are not uncommonly associated with suppuration of the vesicul\u00e6 and the adjacent structures ; and are frequently consequent on intense sexual excitement and onanism. Lallemand gives many instances of this, and relates one in particular, where the urethral membrane was perforated by numerous apertures, through which the pus escaped, so as to present a sieve-like appearance, which he compares to the cribriform lamella of the ethmoid bone. Mr. Curling* mentions a similar case of a young man excessively addicted to onanism, and who died with symptoms of cerebral congestion. The prostate was converted into a multilocular cavity, and the urethra was perforated by numerous large apertures. These openings are the orifices of the prostatic ducts preter-naturally enlarged, suppuration most probably commencing in the minute follicles of the gland. A secretion of a puriform fluid often takes place from the prostatic ducts in cases of severe attacks of gonorrhoea, and small abscesses give way one by one.\nAbscesses of the prostate open in various directions. Not unfrequently they burst into the bladder on the introduction of the catheter. Sometimes they open into the urethra on the side of the veru montanum ; or they make their way forward to the perin\u00e6um, and opening externally terminate in the formation of perin\u00e6al fistul\u00e6. Occasionally they open at once into the rectum ; or they may burst into the adjacent cellular membrane, and even extend to the penis and scrotum.\nUlceration.\u2014This mode of termination of an inflamed prostate is rare. It is one of the most distressing consequences of inflammation, and is only found in cases of hypertrophy of the prostate in old age. It may arise spontaneously, or it may be the consequence of the rude introduction of the catheter. It is invariably attended with most severe symptoms, and is generally indicated during life by the mixture of blood with the urine. The mucous membrane of the bladder adjacent is in a state of high inflammation. Ulceration may exist in various degrees, from simple erosion, as after passing a catheter, to a deep ulcer with indurated edges. In one case, related by Sir Benjamin Brodie, the prostate was found ten or twelve times its natural size, making a large circular projection into the bladder, round the internal orifice of the urethra. Nearly the whole of this portion was\n* Curling, on Diseases of the Testicle.","page":156},{"file":"p0157.txt","language":"en","ocr_en":"PROSTATE GLAND.\n157\nsuperficially ulcerated, and in some places the ulcerated surface was incrusted with a thin layer of coagulated lymph.\nSimple enlargement of the prostate is another consequence of common inflammation. It is one of the not unfrequent sequelae of repeated and neglected attacks of gonorrhoea. It is generally accompanied with induration, and is confined to the lateral lobes, rarely implicating the middle lobe. This condition is occasionally dependent on the irritation or stricture of the urethra, and subsides on the cure of the latter disease.\nTiibercles.\u2014The deposit of scrofulous tubercles in the prostate is rare. When this happens it is generally found to co-exist with similar deposition in the testicles, vesiculae s\u00e9minales, and the adjacent lymphatic glands, and is associated with tubercles in the lungs. It occurs occasionally in the form of one large mass, occupying a large portion of the gland, and causing an increase in its size, or many small distinct depositions are found in various situations. Scrofulous tubercles of the prostate undergo the same progressive disintegration as in other parts, and terminate in abscesses, which take a similar course and direction as common abscesses. I have seen the whole tissue of the gland broken down by the gradual softening of scrofulous tubercles. Mr, Cross, of Cincinnati, met with one instance of this disease ; it was in a young man who died in the Cincinnati Hospital of psoas abscess. There were six or eight small masses of a pale yellowish colour, and of a soft curdy consistence, scattered through different parts of the gland, which was considerably reduced in size ; he thinks they are originally formed in the follicles of the gland. Lallemand also mentions a case in which thirty small abscesses, and the same number of crude tubercles were found in the prostate. There were similar deposits in the kidneys.\nCancer. \u2014 Cancer in any form is extremely rare in the prostate. Carswell regards it as a not uncommon cause of haemorrhage from the urethra, whilst Cruveilhier says that he has never seen an instance of it.\u2014( Walshe on Cancer.) The encephaloid form is that which most commonly attacks this gland ; and, according to Walshe, in M. Tanchon\u2019s tables, out of 8289 fatal cases of cancer, in five death occurred from the disease in the prostate. Rokitanski regards the affection as very rare, and makes allusion only to the encephaloid variety. When the disease attacks the prostate, the gland becomes increased in size. It has been found by Mercier of the size of an ostrich\u2019s egg, \u201c and was attended with effusion of blood into both lobes, communicating with each other and with the urethra by means of false passages.\u201d In a boy, five years old, Mr. {Stafford found the prostate of a globular form, and as bulky as the largest walnut ; the middle lobe was nearly as large as a small hazel nut. \u2014 (Walshe.) By the same author, a case is recorded from LangstafF of an encephaloid growth as big as an orange, which sprang principally from the middle lobe. Cancer of\nthe prostate, as it advances, generally makes its way towards the bladder, and thus forms a bleeding mass in the cavity of that viscus, occasionally filling it up completely, and giving rise to a distinct hypogastric tumour, whichl have known mistaken for a bladder over-distended with urine, the true nature of which was not suspected until after the introduction of the catheter. The cancerous mass at its base was surrounded with a distinct border of ulceration, so characteristic of cancerous tumours, when they have made their way into cavities lined with mucous membrane.\nThe secretion of urine is frequently, under this condition, in a great measure suspended. I have known one case where the bladder was tapped above the pubis, under the idea that it was filled with urine ; but little or no urine escaped, and after death the bladder was found filled with a cancerous tumour originating in the prostate ; and no doubt many such instances have happened. It is a mistake of no very serious consequence, but might be avoided if a careful examination of symptoms were instituted. If an elastic catheter were gently introduced into the bladder, it would be found to give the impression as if it entered a spongy substance, little urine would escape, and that tinged with blood and mixed with shreds of cei ebriform matter : if doubt still existed, a microscopical examination of the substance voided would, I apprehend, set the matter at rest. The introduction of the finger per rectum will assist the diagnosis.\nTrue scirrhus of the prostate is extremely rare. Mr. Travers and Sir Benjamin Brodie both allude to supposed cases of this disease, and from the narration there can be little doubt of their genuineness. The former surgeon examined one case after death, and described the gland as occupied by a tumour, having all the character of scirrhus ; and the latter mentions an instance \u201c where the prostate was found much enlarged, and of a stony hardness.\u201d\u2014(Walshe.)\nFibrous tumours, according to Rokitanski, are frequently found in the prostate. They are of a size varying from that of a pea to that of a hazel nut, are round or oval, causing, when seated at the peripheral portion of the gland, knotty protuberances on its surface. They are always attended with distinct hypertrophy of the gland. This eminent pathologist attaches great interest to them, on account of their similarity to fibrous tumours of the uterus. They are of very frequent occurrence; and in many cases of the enlarged prostate of old men that I have had an opportunity of examining, I found them readily distinguishable on section. This subject has been alluded to before, in the account of the morbid anatomy of the enlarged prostate.\nCystic Prostate.\u2014The prostate, like the kidney, is occasionally the seat of cystic disease. It is characterised by the formation of cysts in various parts of the gland. It is extremely rare. There is an excellent example of it in the Museum of the College of Surgeons. The gland was hypertrophied, and","page":157},{"file":"p0158.txt","language":"en","ocr_en":"PROSTATE GLAND.\n158\non section was found studded here and there with cysts containing fluid. These are, in all probability, dilated and closed follicles ; and in this respect they bear a strong analogy to the cysts of the kidney, which are found to be dilated urinifefous tubes.\nIn the situation of the uvula vesic\u00e6, the fold of mucous membrane is occasionally thrown up, so as to form a remarkable projection or bar at the neck of the bladder. Mr. Guthrie especially directed the attention of surgeons to this, but it has been met with often by others, and there is a good representation of it in Baillie\u2019s Morbid Anatomy. No doubt it has often been confounded with supposed enlargement of the middle lobe of the prostate, with which it is often combined, but of which, in many cases, it is wholly independent. Tn a surgical point of view it is of very great interest. The bar in question, in its most simple form, consists simply of a double fold of mucous membrane, raised at right angles from the bladder ; in other cases, there is found between the layers of mucous membrane a quantity of a substance of an intermixture of elastic and organic muscular tissue, similar to what is found in the neck of the bladder in the normal condition ; whilst in other instances, apparently in the more advanced stages of the disease, the middle lobe of the prostate, considerably hypertrophied, is found as if it had forced its way between the mucous layers, and thus carried the fold with it ; in the latter condition, it will be found in the form of two wing-like processes, one on either side, connecting the middle lobe to the side of the bladder.\nThe disease is necessarily attended with difficult micturition, and leads to retention of urine. The diagnosis between retention from this cause and from enlarged third lobe is difficult, but practically it is not unimportant, as Mr. Guthrie thinks it may be cured. In the rough introduction of the catheter or bougie, the bar is sometimes perforated. This surgeon found in one case as many as fifty calculi behind this projection. It leads, if neglected, to similar changes in the bladder, as are found in cases of enlarged prostate.\nProstatic Concretions. \u2014 The formation of calculous concretions in the minute follicles of the gland are not by any means of unfrequent occurrence. They are not to be confounded with calculi of larger size, which have been long recognised by pathologists, and have been especially alluded to and described by Baillie, Woollaston, Cruveilhier, and Prout. They have very recently been examined by Mr. John Quekett and Dr. C. IT. Jones, the latter of whom has published a paper on the subject in the first number of the Transactions of the Pathological Society, and in the Medical Gazette of August 20th, 1847. The following is the result of the microscopical observations on this subject :\u2014The calculi are found in great numbers in the follicles of the gland, presenting sometimes a deep yellow or red colour; occasionally they are pale and colourless, remarkably small, and scarcely to\nbe distinguished from the tissue in which they are imbedded. Dr. Jones describes their mode of formation thus : \u201c They arise in a large oval vesicle, of a single wall of homogeneous membrane. This is occupied by a colourless finely-mottled substance, in the centre of which a nuclear corpuscle sometimes occurs. Their mean diameter is about ^Jg.^th of an inch. In those of larger size, the envelope is still seen, but the contained amorphous matter is beginning to be arranged in layers concentric to the envelope. In the further stage, the vesicles measure owoth of an inch or more, showing concentric layers, which are more developed on one side than on another, like so many repetitions of the original envelope, the intervals between the layers being occupied by a finely-mottled deep-yellow or red substance. There is a central cavity corresponding with the external contour in its form, which is triangular, with rounded angles or quadrilateral. From this normal appearance, these bodies present numerous variations in form and internal arrangement, and appear to occupy an intermediate position between organic growths and inorganic concretions : to the former, by their vesicular origin and by their growth, which chiefly appears to take place by the dilatation of the vesicle and successive depositions in its interior ; to the latter, by their shape, their tendency to become infiltrated with earthy matter, and to pass into the condition of a dead amorphous mass of a deep yellow red, even almost black. The chemical composition varies probably with their different stages of development, at first consisting of little else but animal matter, then acquiring, especially when in a state of degeneration, calcareous salts, stated by Dr. Prout to be phosphate, with a little carbonate of lime. The colouring matter is unaffected by ether, liquor potass\u00e6, and muriatic acid.\u201d\nFig. 107.\nProstatic concr\u00e9tions.\nThese minute concretions in the follicles and tubes of the prostate have been investi-","page":158},{"file":"p0159.txt","language":"en","ocr_en":"PROSTATE GLAND.\ngated by Mr. Qnekett, who, on submitting sections of the gland either in a healthy or diseased condition, to microscopical examination, has met with them so frequently, that they would seem to be a part of the natural constituents of the gland or its secretion. He describes them as commencing by a deposit of earthy matter in the secreting cells of the gland ; they increase in size either by aggregation, or by deposition in the form of concentric layers ; in the former case they mould themselves to the follicles, in the latter they present the appearance of an ordinary lithic acid calculus on section. Where many cells were together, the parietes of the cells in contact are destroyed ; so that by adding dilute muriatic acid, and thus dissolving the earthy matter, a multilocular cavity remains. In consequence of the manner in which they mould themselves to the follicles, they frequently present an appearance externally like mulberry calculi.*\nThe opinion of Prout that the deposition of earthy salts is the result of a deranged action in a mucous membrane appears thus fully borne out. In a case which I recently examined with Mr. Qnekett the concretions were exceedingly numerous ; and this was especially remarkable in the middle lobe of the prostate. The gland had been removed from a young man who had died of phthisis, and was of the natural size. The middle lobe was much firmer than either lateral lobe They are soluble in acetic acid by the aid of heat.\nProstatic Calculi.\u2014It is most probable that these concretions undergo an early solution ; thus yielding up their granular or amorphous contents to form apart of the secretion of the gland. This is the opinion of Dr. Jones. But if they are not removed in this maimer they become the nuclei of prostatic calculi.\nProstatic calculi are thus formed in the gland, occasionally in immense numbers ; they are generally rounded in form, and from their pearly semi-transparent appearance, Dr. Wollaston compared them to grains of pearl barley. They become covered with a brownish coating from a deposit from the natural secretion of the gland. Continuing to increase in size, they come in contact with one another, and at the points of contact are as it were articulated together. They are smooth upon the surface, and often resemble porcelain from the high polish they obtain. As they increase still further in size they cause absorption of the surrounding glandular substance, and thus convert the gland into a multilocular bag, in which as many as fifty or sixty calculi have been seen. In this condition, if the finger is passed per anum, the prostate gives the feel of a bag of marbles. Sometimes there is only a single large cavity in one lobe filled with a single calculus. The smaller stones often escape into the bladder through the dilated ducts,and are readily extracted by the urethral forceps. When divided they exhibit a radiated and laminated structure; or they are compact.\n* See Guy on Cause and Treatment of Stricture of the Urethra, and Diseases of the Prostate Gland. 1845.\n159\nFrom the analysis which has been made of the prostatic calculi in the College of Surgeons, it appears that the relative proportion of phosphoric acid and lime in all the varieties of these calculi appears to vary considerably, although they may, in all probability, be reduced to two salts, \u2014 the neutral phosphate of lime, or the diphosphate, which exists in those varieties that are partially fusible before the blowpipe, and which generally exhibit a crystalline structure; and the basic phosphate of lime which is completely infusible by the mouth of the blowpipe. In estimating the fusibility of these compounds, care must be taken that none of the triple phosphate is present.* When they pass into the bladder, they excite irritation of its mucous surface, and become coated with the triple phosphate ; or if a large stone remains in the prostatic portion of the urethra, it may cause a deposit of lithic acid on its surface from the urine which is continually passing over it. A single calculus sometimes extends from the prostate into the membranous part of the urethra, which becomes much dilated. In these cases the calculus has usually an elongated, somewhat conical figure, and consists of two or three separate portions, which are closely adapted to each other, and have polished articulating surfaces at the point of contact. The rounded extremity of one calculus is often received into a corresponding concavity of another. These calculi almost always contain a larger portion of phosphate and carbonate of lime, than those found in any other situation. When the prostate is completely disorganised and converted into a mere cyst, the calculi found in its cavity are of the fusible character, or contain more or less of the triple phosphates.\nIt sometimes happens that the phosphates are secreted by the prostate in immense quantities, and are excreted with the urine, giving it a milky aspect. This may be confounded with a similar deposit from the urine itself, but it is generally accompanied by symptoms of irritation of the prostate gland and neck of the bladder \u2014 as discharge from the urethra ; hence the diagnosis is not difficult.\n\u201c Vogel, in his pathological anatomy of the human body, has given an account of these prostatic calculi : he described them of small size, not larger than a pin\u2019s head, and usually of a brownish, reddish-brown, or yellowish-brown colour, presenting a crystalline or laminated arrangement, with a polyhedric or facetted surface. He says that they are formed by a precipitate of phosphate of lime.\n\u201c Lassaigne has given an analysis of the quantitative composition of these concretions. Thus in 100 parts there are contained\nBasic phosphate of lime .\t.\t84*5\nCarbonate of lime .\t.\t.\t0*5\nAnimal matter (mucus, &c.)\t. l\u00f4'O\nIt is presumed that they are formed by a deposition of these salts when existing in excess in the prostatic secretion. Similar concre-\n* Catalogue of Calculi contained in the Museum of the Royal College of Surgeons in London, 1842.","page":159},{"file":"p0160.txt","language":"en","ocr_en":"PROSTATE GLAND.\n160\ntions are occasionally met with in the vesicul\u00e6 s\u00e9minales and vasa deferentia ; but, according to Peschier, their analysis differs slightly from prostatic concretions. Thus he found in 100 parts\nPhosphate of lime\t.\t.\t.\t900\nCarbonate of lime\t.\t.\t.\t2*0\nAnimal matter .\t.\t.\t.\t1*0\u201d*\nComparative Anatomy. \u2014 Assuming the prostate to be represented by a glandular structure placed at or near the termination of the vas deferens, it is found in many of the invertebrate animals. As a general rule, it is only discovered in those possessed of an intromittent organ ; this, however is not invariable. In the medicinal leech, among the annellata, according to Owen and Brandt, the two vasa deferentia and the two sacculated vesicul\u00e6 s\u00e9minales send their ducts to a common prostatic body, from which the penis is continued. \u201c In the centipede, among myriapoda, a minute efferent tube is continued from both ends of each testis, which tubes unite with those of the adjoining organ, and ultimately form a single vas deferens, which, having received the ducts of three pairs of small prostatic glands, terminate in the cloaca. In the male aphis there is a long pyriform vesicular gland attached to each lateral vas deferens, and in many insects representatives of prostatic glands communicate with the ductus ejaculatorius.\u201d f In the slug, among gasteropoda, the vas deferens is joined by the short and simple duct of a small prostatic sac ; and this is the case in the common snail, in whom the duct is, however, longer. In the cephalopoda, as in the octopus, \u201c the anterior extremity of the contractile vesicula, into which the efferent duct opens, communicates with a wide, bent, ccecal tube (prostate), with thick glandular parietes, and having the form of a- simple pouch in the sepia. The prostate in the sepiola communicates by a long and slender duct with the vesicul\u00e6 s\u00e9minales.\u201d t\nIn mammalia, two varieties of prostate are found, distinguishable as to structure from each other : one, the cellular, in which small cells open into a central cavity, from which a large duct arises ; and the other, the follicular, composed, as M\u00fcller says, \u201c of large intesti-nules, or larger ramose follicles.\u201d\nIn the ape tribe, the form of the prostate is larger from above downwards than from before backwards, and surrounds the urethra in the form of a crescent. In position, size, and structure, it resembles that of man. In the viandril some accessory lobes are found. The prostate of the ma/cis sends off two prolongations, which surround the excretory ducts of the vesicul\u00e6 s\u00e9minales.\nIn the tarsier, there are two distinct glands, placed in front of the vesicul\u00e6 s\u00e9minales, on the side of the urethra.\nThe galeopitheci have a single prostate\n* Yogel\u2019s Pathological Anatomy of the Human Body, translated by Dr. G. E. Day. f Owen\u2019s Lectures on the Invertebrate Animals.\nof large size, surrounding the base of the vesicul\u00e6.\nIn the roussette, the prostate is simple, and surrounds a large portion of the circumference of the urethra.\nIn the dormouse, it surrounds the whole circumference of the urethra, and is composed of a number of lobules.\nIn the hedgehog, the prostates are four in number, and they belong to the tubular class. The superior prostates are the larger, and are composed of long flexuous tubes, united into lobules, which form lobes, whose tubes reunite to form a single excretory duct, which pierces the superior surface of the urethra. They are attached by processes of the peritonaeum to the abdominal muscles. \u2014 (Hunter.) Two other bundles of smaller size, and of a rounded form, represent the inferior prostates. They are composed of smaller tubes, which separating in the form of a fan, pass towards the circumference of the gland, and terminate in ccecal ends. The excretory ducts open one on either side of the veru montanum. The tubes are composed of membranes of extreme delicacy.\nIn the mole, the prostate is single, and is formed of membranous tubes folded upon themselves. At the period of heat, it increases so enormously as to exceed the urinary bladder in size ; it is placed around the urethra in front of the bladder.\nThe prostate of the hear is confounded with the dilatation of the united vasa deferentia. It surrounds the beginning of the urethra, and forms a bed for the canal of variable thickness, according to the species.\nIn the otter, weasel, and marten, it consists of a thin layer, without any enlargement. In the ichneumon, there is a gland of considerable size, composed of distinct lobes, situated on the rectal aspect of the urethra ; each lobe has a distinct duct.\nIn the dog and cat, it forms a large prominent collar around the urethra; it resembles the human prostate in structure, and mode of termination of its ducts.\nIn the hyena, it is of large size ; and in the civet it forms two tubercles in front of the insertion of the vasa deferentia.\nIn the marmott, among the rodentia, it is divided into two lobes, and forms a considerable swelling around the commencement of the urethra.\nThe glandular covering of the vesicul\u00e6 s\u00e9minales, which extends below the muscular structure of the urethra, represents the prostate gland in the rabbit.\nIn the squirrel, it is as long as the muscular portion of the urethra, of large size, ovoid in shape, flattened from above, and is divided into two lobes ; it adheres to the urethra by two points, where its excretory ducts penetrate the canal.\nAccording to M\u00fcller, in the rat genus, besides three glands of different structure on each side, the urethra is surrounded by a glandular mass, consisting of bunches of vesicles, representing the prostate.","page":160},{"file":"p0161.txt","language":"en","ocr_en":"PROSTATE GLAND.\n161\nIn the agonti, the prostates are composed of a trunk, divided into branches and ramusculi, terminating in vesicular extremities.\nIn the guinea-pig, the situation of the prostate is occupied by a number of tubes folded upon themselves, and connected together by loose cellular membrane.\nThe elephant has four prostate glands, two on each side, external to the vesicul\u00e6 s\u00e9minales, and near their base ; they are of unequal size, and very small in proportion to the size of the other glands connected with the generative function. They are muscular externally, and are indistinctly lobulated. They form a good illustration of the cellular type of prostates, each consisting of a principal cavity, into which smaller cavities open. The smaller cells represent so many cul-de-sacs of various sizes, communicating with each other and with the principal cavity ; the excretory duct is of large size, and passes by the side of that of the neighbouring gland, to open separately in the urethra by the side of the veru montanum.\nIn the wild hoar the prostate is divided into lobes, is very compact in its structure, and forms a considerable projection at the beginning of the urethra. There is also found in this animal a glandular mass, analogous to the prostate, surrounding the muscular portion of the urethra, thickest at the commencement of this canal, and surrounded by muscular fibres coming from the neck of the bladder.\nIn solipedes there are two prostates, situated by the side of the vesicul\u00e6 ; the cavities of these are large, and the parenchyma small in quantity ; they are covered by muscular fibres coming from the vesicul\u00e6 and neck of the bladder ; their excretory ducts terminate by many orifices on either side of the ducts of the vesicul\u00e6.\nThe ruminants have also two prostates, precisely similar to the preceding. They are larger in the ram and bull, and are composed of distinct lobes, each containing small cells, which communicate with a large central cavity ; this opens by a duct in a large lacuna of the veru montanum, either internal to or behind the vas deferens. In the stag, axis, and buffalo they are smooth, and of a regularly oval shape, and have a central cavity communicating by large openings with smaller cavities ; each has a single duct, which terminates generally behind the corresponding vas deferens. The only difference in this class is in regard to size ; for in the chamois each is as large as a pullet\u2019s egg, and contains a propor-tionably large cavity ; so that it has been occasionally mistaken for a reservoir of seminal fluid. In the seal, amongst the quadri-r\u00e8mes, it resembles that of the otter. In the cetacea there is a large glandular mass, covering a large portion of the first part of the urethra, especially at the upper part, covered by a strong muscle. When a section is made, it is found to consist of large cells ; its ducts open separately by numerous orifices on the urethra.\nIn the marsupial sub-class, as in the kangaroo, the prostate is found surrounding the commencement of the urethra, of large size, and conical in shape, with base behind, apex in front ; it is surrounded by a strong musculo-membranous capsule. It exceeds in diameter the contracted bladder, and is made up of tubes ramifying perpendicularly to the urethra, which subdividing terminate in minute coeca upon the surface of the gland. It presents a similar arrangement in the opossum ; whilst in the wombat its existence is doubtful.\nCarus has described in birds a dilatation of the vas deferens, a rudimentary vesicula semi-nalis, and a small gland like a prostate near the termination of the vas deferens. This is not admitted by Owen. In the ornithorynchus paradoxus we find two round glandular bodies representing Cowper\u2019s glands, but which may be fairly regarded as a rudimentary prostate.\nAmongst amphibious reptiles, glands analogous to the prostate, or Cowper\u2019s glands, are found. In the salamander they are composed of two lobes ; one placed horizontally, and the other vertically ; the former, in the common salamander is heart-shaped, with the point behind ; and in its centre a fissure is seen. The vertical lobe is raised obliquely towards the dorsal aspect, so that an interval is left between them for the passage of the kidneys ; a muscle separates the two.\nIn the black salamander, each gland is composed of two lobes. In the Tritons the part of the prostate which corresponds with the inferior lobe is still more complicated; it forms the wall of the vestibulum in the shape of a cup. Besides this, there are two pelvic prostates corresponding to the vertical lobe of the vestibular prostate of the salamander ; they occupy the dorsal aspect of the vestibule and the pelvis, and each is subdivided into two lobes. Their excretory ducts open in the mesian line of the furthest point of the vestibule. The Tritons have a third prostate occupying a large portion of the abdominal muscles under the peritonaeum. In structure they resemble those of the hedgehog.\u2014 (Cuvier.)\nBibliography. \u2014 Natural Structure. \u2014 See anatomical works in general. M\u00fcller, De penitiori Glandularum Structura, 1830.\nPhysiology.\u2014For the opinions of the ancients on this subject see Haller's Elementa Physiologi\u00e6, vol. 7., and the opinions of modem physiologists are set forth in the works of physiology generally. Cowper, Glandularum quarundam nuper detectarum, 1702.\nComparative Anatomy.\u2014See vol. 8. of Cuvier's Le\u00e7ons d\u2019Anatomie Compar\u00e9e. Lectures on Comparative Anatomy, by Dr. Grant, in the Lancet, and Lectures on Comparative Anatomy by Rymer Jones. See also various articles by Professor Owen on Comparative Anatomy in this Cyclopaedia. Owen's Lectures on the Comparative Anatomy of the Invertebrata, 1843. Wagner's Elements of the Comparative Anatomy of the Vertebrate Animals, translated by Tulk, 1845.\nDevelopment .\u2014Ackerman, Infantis Androgyni Historica, Jena, 1805. Meckel, Abhandlungen aus der menschl. und vergl. Anatomie, 1806. Tiede-man, Der Kopflosen Missgeburten, 1819. M\u00fcller, Bildungeschichte der Genitalien, 1830, and Archiv,\nM\nVOL. IV.","page":161},{"file":"p0162.txt","language":"en","ocr_en":"162\tPROTEIN.\n1847. Rathke, Abhandl. und Beitr\u00e4ge, 1830. Valentin, Entwickelungsgeschichte, Berhn, 1835. Baer, Entwickelungsgeschichte, 1837. Coste, Embryogenie compar\u00e9e, 1837. Bischoff, Entwickelungsgeschichte der S\u00e4ugethiere und des Menschen, 1842. Weher, Zus\u00e4tze zur Lehre vom Baue der Geschlechtsorgane, Leipsig, 1846.\nMorbid Anatomy.\u2014Bonetus, Sepulchretum,1700. Morgagni\u2019s De Sedibus et Causis Morborum, 1760. Hunter on the Venereal Disease, 1788, 2d edition. BailUe\u2019s Morbid Anatomy, 1793. Home, Practical Treatise on the Diseases of the Prostate Gland, 1811. Wilson on the Diseases of the Urinary Organs, 1821. Howship on Diseases affecting Urinary Organs, 1823. Lallemand, Observations sur les Maladies des Organes Genito-Urinaires, 1825-27. Amussat, Le\u00e7ons sur les Retentions d\u2019Urine Caus\u00e9es, &c. &c., 1832. Guthrie on the Anatomy and Diseases of the Neck of the Bladder and Prostate Gland, 1834. Mercier. Recherches sur les Maladies de la Prostate des Vieillards, 1836. Carswell\u2019s Pathological Anatomy, 1833-38. Crosse\u2019s Pathological Anatomy, vol. ii., Boston, 1839. Coulson, Diseases of the Bladder and Prostate Gland, 1840. Civiale, Maladies des Organes Genito-Urinaires, 1841. Sir Benjamin Brodie on the Diseases of the Urinary Organs, 3d ed. 1842. Rokitanski, Handbuch der Patholog. Anatomie, 1844. Guy on Diseases of the Prostate Gland, 1845. Engel, Entwurf einer Pathologisch Anatomischen Prop\u00e4deutik. 1845. Walshe on Cancer.\nConcretions and Calculi.\u2014Marcet, An Essay on the Chemical History and Medical Treatment of Calculous Disorders, 2d edition, 1819. Prout, An Enquiry into the Nature and Treatment of Diabetes, Calculus, and other Affections of the Urinary Organs. Cuveilhier\u2019s Pathological Anatomy, 1828. Sir Astley Cooper\u2019s Lectures, by Tyrrell, 1824-7. Crosse on the Nature and Treatment and Extraction of the Urinary Calculus, 1835. Catalogue of Calculi of Royal College of Surgeons, 1842. Dr. C. H. Jones on Calculous Concretions of the Prostate ; see Medical Gazette for Aug. 20. 1847. Vogel\u2019s Pathological Anatomy, translated by Dr. G. JE. Day, 1847. Dupuytren sur les Calculs de la Prostate, dans Bull, de la Gai. de Med., torn. vii. p. 135.\n(John Adams.)\nPROTEIN, (from trpuniw, I am first,) is the name given by its discoverer, Mulder, to a chemical substance of the highest interest and importance ; since it appears to form the basis of by far the greater portion of the bodies of all animals.\nWhen pure, fibrin, of which animal flesh or muscle chiefly consists, is analysed, it is found to be composed of C40 H31 Ns 012 and a small quantity of sulphur and phosphorus. Albumen, whether obtained from the serum of the blood, white of egg, or any of the albuminous tissues of the body, is found also to consist of C40 H31 N5 012 and a little sulphur and phosphorus. Casein, too, or the curd of milk, yields on analysis C40 H31 Ns 012 and a little sulphur, differing from the others in not containing any phosphorus. Hence it appears that fibrin, albumen, and casein, are, chemically speaking, almost identically the same ; and that if we were enabled to separate from each the minute portion of sulphur and phosphorus, we should obtain a compound in every case the same. Such a substance is protein ; so called from its being the initial letter, as it were, of all this class of organic principles.\nI shall first describe it as obtained artificially, together with the changes produced\nupon it by reagents, and afterwards speak of its more common natural modifications, which play so important a part in building up the fabric of organic beings.\nProtein is most readily obtained from the white of egg, which, as is well known, consists of a solution of nearly pure albumen, contained in a delicate network of cellular membrane. This substance should be well beaten up, in order to break the minute cells in which the albumen is lodged, mixed with about an equal bulk of water, and filtered through a linen cloth to separate the cellular matter, which is insoluble in water ; or it may be allowed to stand until this has subsided to the bottom of the vessel, when the clear liquid may be poured off, or removed by means of a syphon. The solution should then be evaporated to dryness on a water bath, the residue pounded in a mortar, and washed successively with alcohol, ether, and dilute hydrochloric acid, by which means it is purified from extractive matters, fat, phosphate of lime, and the other salts with which it is associated. The pure albumen thus obtained is digested for several hours in a dilute solution of caustic potash, at a temperature of from 120\u00b0 to 130\u00b0 ; it readily dissolves in the alkaline solution, and the sulphur and phosphorus are gradually separated, forming sul-phuret of potassium, and phosphate of potash. Acetic acid is now added in very slight excess, when the protein separates in the form of a white flocculent precipitate, which, when washed with water until all soluble matter is removed, and dried at 212\u00b0, is pure protein. In order to asertain, however, whether the whole of the sulphur is removed, a small quantity should be dissolved in potash, and some of the solution boiled in two test tubes, to one of which a drop of solution of acetate of lead is added. They will both become rather brown, owing to the decomposition of the protein; but if any sulphur is present, the portion to which the lead had been added will become, after boiling for a few minutes, much darker in colour than the other, owing to the formation of sulphuret of lead.\nProtein, when dry, is a hard, semitransparent brownish yellow substance, having a good deal the appearance of amber. It is without taste or smell, and when exposed to damp air rapidly absorbs moisture, which may be expelled by heating it to about 220\u00b0. When further heated it melts, and almost immediately afterwards begins to decompose, leaving a residue of charcoal, which, if ignited for some little time in the air, burns completely aw'ay, leaving scarcely a trace of incombustible ash. Protein is insoluble in water, alcohol, and ether ; it appears to combine with most of the mineral acids, forming compounds which may be considered neutral, some of which are soluble in water, though insoluble in an excess of the acid. Tribasic phosphoric, and acetic acids, however, do not reprecipitate it when added in excess. It combines also with the alkalies, giving rise to soluble compounds, from which the protein may be again separated by the addition of an acid. It may be thrown down in an","page":162},{"file":"p0163.txt","language":"en","ocr_en":"PROTEIN.\t163\nnsoluble form from any of its acid solutions by the ferrocyanide and ferridcyanide of potassium, which are among the most delicate tests for it ; also, by absolute alcohol, tannin, many of the metallic salts, and by carefully neutralizing with an alkali.\nTritoxide of protein. \u2014 Though protein may be said to be absolutely insoluble in water, it may by prolonged ebullition with access of air be rendered completely soluble. This is owing to the formation of a soluble oxide of protein, represented by the formula C40 H31 Ns 015 + HO, containing three additional equivalents of oxygen, and which Mulder has called tritoxide of protein. This interesting compound may be more easily prepared from the chlorite of protein (which I shall presently describe) by the addition of ammonia ; the muriate of ammonia which is formed at the same time being afterwards separated by washing with alcohol.\nTritoxide of protein has, when dry, very much the same appearance as protein ; it is readily soluble in water, nearly insoluble in alcohol, and completely so in ether. It dissolves in sulphuric and hydrochloric acids and the alkalies, but is precipitated from its solution in water by dilute sulphuric acid, tannin, and several metallic salts,'forming compounds with their oxides, having for the most part the formula (C40 Hai Na 018 + MO) + (C40 H31 N5 OlS + HO). With nitric acid it behaves like protein, becoming yellow, and forming xanthoproteic acid. Water in which meat has been boiled, as broth, soup, &c., owes its nourishing properties mainly to the tritoxide of protein which is formed during ebullition ; and according to Mulder, both this and the binoxide are formed in meat during the process of roasting.\nBinoxide of protein. \u2014 The other compound of protein and oxygen just alluded to, called by Mulder the binoxide, consists of C40 H31 Ns 014 or the elements of protein plus two equivalents of oxygen. Both this and the tritoxide exist ready formed in the buffy coat of the blood, which, according to Mulder, consists chiefly of these two oxides. Binoxide of protein may be obtained by boiling fibrin in water for many hours, when the protein gradually combines with at first two, and eventually three equivalents of oxygen, becoming successively binoxide, and (if the ebullition is continued long enough) tritoxide; the latter dissolves as it is formed, and may be separated from the insoluble binoxide by washing with water. This process is, however, tedious, and it is more readily obtained from hair, in the following manner. The hair should be freed from grease by washing with ether, and dissolved in rather a dilute solution of caustic potash, with the aid of a gentle heat, not exceeding 120\u00b0 or 130\u00b0. A mixed solution of protein and its binoxide is in this way obtained, from which the protein is first separated by neutralizing the solution with acetic acid, and after filtration the binoxide is precipitated by the further addition of a decided excess of acid. It appears as a yellowish flocculent precipitate,\nand when washed and dried has a dark resinlike appearance,\nBouchardat obtained a substance by digesting moist fibrin in water acidified with one or two-thousandth of its weight of hydrochloric acid, in which it gradually dissolved, which he called albuminose; it has since been prepared and analysed by Mulder, who considers it to be identical with binoxide of protein; but Liebig, who has recently examined it, says that it cannot be obtained free from sulphur, and consequently that it is not pure binoxide of protein. This oxide is insoluble in water, alcohol, and ether, but dissolves in most of the dilute acids, and in solutions of potash and ammonia ; it is precipitated from its acid solutions by ferrocyanide and ferridcyanide of potassium, and several other metallic salts. Nitric acid decomposes it, forming xanthoproteic acid, but the yellow colour produced by it is less intense than that obtained with protein.\nThese oxides of protein possess considerable physiological interest, from the circumstance that they are contained in the blood, in small quantity during health, but much more abundantly in some forms of disease. It is probable that they are formed during every act of respiration by the action of the inspired oxygen on the globules or fibrinous matter of the blood ; and Mulder is of opinion that it is through their instrumentality that the atmospheric oxygen is conveyed to the capillaries, there to be employed in effecting the necessary changes in the substance of the body. During fever, when respiration goes on with more than ordinary rapidity, these oxides are formed in much larger quantity; hence the buffy coat of diseased blood, which was formerly considered to be merely fibrin, consists almost entirely of oxidized protein ; and pus, false membranes, and other morbid products contain it in considerable quantity.\nMulder has recently obtained a third oxide of protein, represented by the formula C40 H31 Ns 020 or protein plus eight equivalents of oxygen. As it has not, however, been found to exist naturally in the animal body, it is inferior in point of interest to the other two. Like the tritoxide it is soluble, and is obtained by boiling glutin or yeast for a length of time in water.\nBy the action of chemical reagents on protein a multitude of new compounds are formed, most of which have been only imperfectly examined, and indeed possess but little real interest. I will describe a few of the most important.\nProtein and chlorine. \u2014 When a, current of chlorine is passed through a solution of albumen, or any of the other modifications of protein, a substance is produced, containing C40 h31n5 015 C1x, which Mulder considers to be a chlorite of protein, (C40 H31 N5 012 + Cl 03). It appears to be formed at the expense of three equivalents of water ; three equivalents of hydrochloric acid and one of chlorous acid being simultaneously produced, the latter uniting with the protein. It separates as a snow-white flaky precipitate, and\n\u00bbI 2","page":163},{"file":"p0164.txt","language":"en","ocr_en":"] 64\tPROTEIN.\nwhen dried, is hard, semitransparent, and nearly colourless. This substance is sometimes called chloroproteic acid, since it is found to combine without decomposition with several metallic oxides. When treated with ammonia,however, it is decomposed, nitrogen gas is given off, and tritoxide of protein is formed, together with hydrochloric acid, which combines with the excess of ammonia. This is the most convenient way of preparing the tritoxide, as it is easily separated from the muriate of ammonia by washing with alcohol, in which it is insoluble.\nProtein and nitric acid. \u2014 By the action of nitric acid on protein compounds, oxalic acid, ammonia, nitrogen, nitric oxide, together with a new compound called Xanthoproteic acid, are obtained ; which latter, being insoluble, is readily purified by washing with water. Xanthoproteic acid is of a bright yellow colour, from which circumstance it derives its name : it reddens litmus, is uncrystallizable, tasteless, and, when strongly heated, does not melt, but is decomposed, giving off the smell of burnt feathers. It is soluble in strong acids, and when water is added to the solution, a precipitate, containing both the acids in a loose state of combination, is thrown down. It forms with metallic oxides true salts, most of which are of a deep orange-colour, and insoluble in water ; the alkaline xanthoproteates, however, are soluble. It is bibasic, and consists of C34 H24N4012+2 HO. The troublesome and indelible stain which nitric acid causes when dropped on the skin is owing to the formation of this substance.\nProtein and sulphuric add. \u2014 When protein is treated with strong sulphuric acid it forms a white insoluble compound, called by Mulder sulphoproteic acid, containing C40, H31, N5, 012,+ S03. To purify it, it should be washed with cold water as long as the washings give a precipitate with baryta water: when dry, it is hard, tough, semitransparent, and nearly colourless ; it forms with alkalies, soluble, and with the other oxides, insoluble, sulphoproteates.\nThere is another compound of protein and sulphuric acid, called by Mulder sidphobiproteic add, which is formed when dilute sulphuric acid is gradually added to a solution of protein in acetic acid : it appears to consist of two equivalents of protein, two of water, and one of sulphuric acid, and is represented by the formula C80 H62 N10 O 24+ 2 HO -j- S03. If a protein compound be heated with sulphuric acid it becomes purple, but the colour disappears on dilution with water.\nProtein and hydrochloric add. \u2014 Concentrated hydrochloric acid slowly dissolves protein even at common temperatures, and still more readily when gently warmed : the solution is at first yellowish, but if the air is not excluded, the colour soon changes to a deep blue or purple. The appearance of this blue colour is one of the most striking tests for protein and its modifications, fibrin, albumen, and casein, as it is produced in them all by hydrochloric acid. When allowed to boil, if\nthe acid is strong, a black substance similar to ulmic acid is formed, together with muriate of ammonia.\nProtein and potash. \u2014 The action of potash on protein possesses considerable interest. When treated with a dilute solution of the alkali, in the cold, it readily dissolves, and, according to Mulder, a little ammonia is always given off, however dilute the alkaline solution may be. When boiled in a strong solution of potash it is completely decomposed ; ammonia, carbonic, and formic acids are formed, together with three new compounds, which have been called leudn, protid, erythroprotid. To obtain these substances in a state of purity, the following process may be adopted. The protein compound is boiled with solution of potash as long as any ammonia is given off, and then neutralized with sulphuric acid, which disengages the carbonic acid and combines with the excess of potash: the solution is then evaporated to dryness on a water-bath, by which means the greater part of the formic acid is volatilized. The organic compounds are then separated from the sulphate of potash by repeated boiling in alcohol, in which they are all more or less soluble. On cooling, the alcoholic solution deposits the erythroprotid, which is of a reddish-brown colour, and nearly insoluble in cold alcohol. When left for a short time to spontaneous evaporation, the leucin crystallizes out, and the liquid then contains only protid, with a trace of erythroprotid, and a little formiate of potash.\nErythroprotid, when pure, is of a fine red colour ; it is soluble in boiling alcohol and in water, and is precipitated from its solutions, of a rose red colour, by many of the metallic salts, as those of silver, mercury, and lead : it is thrown down also by tannic acid. When a current of sulphuretted hydrogen is passed through its aqueous solution, it gradually becomes colourless ; but if the solution, thus treated, be kept in vacuo a short time, the colour returns. The formula of erythroprotid is C13 H8 N05.\nProtid (C13 H9 N04) may be separated from the impure alcoholic solution by diluting with water, and precipitating with subacetate of lead, which throws down protid, but not erythroprotid, which latter is also present in small quantity. The precipitate is washed with water, and decomposed by sulphuretted hydrogen ; the solution is filtered and evaporated, after which the protid is left in a state of purity. It is of a pale yellow colour, amorphous, and, when dry, very brittle. It differs from erythroprotid in not being precipitated from its solutions by any of the metallic salts except basic acetate of lead; while erythroprotid is not affected by that reagent : consequently if the two exist together in solution, the erythroprotid may be thrown down by the neutral acetate, and the protid by the basic salt.\nLeucin, which gradually separates when the alcoholic solution is concentrated, is a crystalline substance closely resembling chloresterine in appearance : it consists of C12 H12 N04.","page":164},{"file":"p0165.txt","language":"en","ocr_en":"PROTEIN.\nIt is tolerably soluble in water and alcohol, but quite insoluble in ether ; and when heated to about 34*0\u00b0 it sublimes without decomposition. When treated with nitric acid, a crystalline nitroleucic acid is formed, consisting of C12 H13 N04 + NOs + HO.\n2Equivts. Erythroprotid C2 6 Hx\t\t\t\t010\n2\t99\tProtid . . . . C26 H18\tn2\to8\n2\t99\tLeucin . . . . C24 H24\tn2\to8\n4\t99\tAmmonia . .\tH12\tn4\t\n2\t99\tCarbonic acid C2\t\t04\n1\t99\tFormic acid C2 H\t\to3\nc80h71n10o33\n165\nMulder has attempted to explain by the following equation how the elements of protein may dispose themselves, in order to produce the compounds just described.\n'2 Equivts. Protein . . Cso H62 N10 024 9\t\u201e Water ... H9\t09\nc80h71n10o33\nEquations of this kind, though sometimes of great service in simplifying complicated chemical changes, are always to be looked upon merely as representing possibilities, and should not be adopted without great caution ; much mischief has indeed already been done from the too ready credence in the truth of hypotheses which have thus been made to appear simple and striking, though really in the highest degree at variance with what further research has proved to be the truth.\nThe action of potash on protein and its compounds derives additional interest from the circumstance that it may afford a clue to the manner in which the gelatinous tissues of the body are formed from protein compounds, a problem at present very far from being satisfactorily solved. Both protid and erythroprotid are somewhat similar in composition to chondrin and glutin ; and leucin, which Mulder considers to be actually a constituent of protein, may be obtained also from gelatine, clearly showing some connection to exist between the protein and gelatine compounds : moreover we find the gelatinous tissues formed in the herbivora, though not a trace of any analogous substance can be detected in their food. These circumstances tend to the conclusion that the chondrin and glutin of the herbivora at least, are in some way derived from the proteinaceous matters of the food, and Mulder has suggested that it may be owing to a change produced by the free alkali of the serum, not unlike that which I have described as the effect of the action of potash on the protein compounds. Glutin consists, according to that chemist, ofC13H10 N2 Os, and it is easy to represent by a chemical equation how such a compound may be formed from either protid or erythroprotid. When these latter substances are formed in the laboratory by the decomposition of protein by potash, it is probable that two equivalents of ammonia are at the same time produced ; and we may conceive that in the living body the elements which, when not so circumstanced, unite to form ammonia, remain combined with those of protid and erythroprotid ; in that case we should have compounds containing protid plus ammonia, C13 H9 N04 + NH3 = C13 H N O. : and erythroprotid plus ammonia,\nc\u201dh:n\u00f45 + nh, = c13hi1n1 0\u201e If now we suppose that these two hypothetical\nsubstances, Cl3 H12 Na 04 and Cl3 HX1 N2 Os become united, the one to three equivalents, and the other with one equivalent of oxygen, a supply of which is always present in the arteries, we should have in the case of protid, C13 H12 N2 07 or C13 H10 N2 05 + 2 HO ; and in that of erythroprotid Cx 3 Hx x N2 06 or G, 3 H1? N2 0? -f- HO, so that in both cases glutin might be formed. This hypothesis is highly ingenious and interesting, though the probability of its correctness is somewhat lessened by the circumstance that neither leucin, protid, nor erythroprotid, have yet been detected in the animal organism ; and moreover it is uncertain whether the alkaline reaction of the blood is owing to the presence of free alkali, or of tribasic phosphate of soda.\nWe now come to the consideration of the natural modifications of protein, which we find composing the chief bulk of the bodies of animals, viz .fibrin, albumen, and casein.\nFibrin. \u2014 This is a substance of the highest importance in the animal economy, since it is the material of which the solid framework of the muscles and some other tissues mainly consist ; and it is also found dissolved in the blood, from which it separates spontaneously after removal from the body, forming the clot or crassamentum. The following table shows the average proportion of fibrin in several animal products.\n100 parts\tFibrine.\nBlood of the hog contain\n\u201e\tsheep ......\nBeef (muscle of) ......\nVeal \u201e\t.......\nMutton ,,\t.......\nPork \u201e\t.......\nChicken \u201e\t.......\nCod\t\u201e\t.......\nHaddock \u201e\t.......\nSole \u201e\t.......\nCalf\u2019s sweetbread (thymus) ..................\nFibrin may be obtained from lean animal flesh by cutting it into thin slices and washing with water till it is colourless ; it is, however, impossible to obtain it pure in this way, as it is always associated with fatty matters, nerves,\nM 3\n0*46\n0-37\n0-30\n20-0\n19*0\n22-0\n19-\t0\n20-\t0\n14-\t0 13'0\n15-\t0\nIncluding a little albumen.\n8*0","page":165},{"file":"p0166.txt","language":"en","ocr_en":"166\nPROTEIN.\nand membrane. It may be obtained in a state of purity from the blood, in which, as already mentioned, it exists in a soluble condition, but remarkably prone to assume the solid form as soon as removed from the body. The blood, as soon as drawn, should be rapidly beaten up with a bundle of wires or twigs, to which the fibrin attaches itself in the form of solid amorphous filaments, coloured red by a quantity of the globules entangled in its pores during the coagulation ; these latter may be removed by placing the coagulum in a piece of linen cloth, and washing with a stream of cold water until all colour disappears. It still contains fatty matters, inorganic salts, and a considerable quantity of water, all which may be removed by drying on a chloride of calcium bath at a temperature of about 250\u00b0, pounding the hard mass in a mortar, washing with alcohol, ether, and dilute hydrochloric acid, and lastly, macerating in water until all soluble matter is dissolved out, when it should be again thoroughly dried. Thus prepared, it is of a yellowish colour, hard, brittle, and, when perfectly free from fat, transparent. It is tasteless, and insoluble in alcohol, ether, and water ; but in the latter it softens, swells up, and reassumes the appearance it had previous to desiccation. Though insoluble in both hot and cold water, it is converted by prolonged boiling, first into binoxide and eventually into tritoxide of protein, which latter is soluble in water. Most of the acids, when in a concentrated state, cause fibrin to swell up and assume a gelatinous appearance. It was observed by Scherer that when moist fibrin is placed in an atmosphere of oxygen, it has the property of absorbing and retaining a portion of the gas ; an effect no doubt accompanied by the formation of one or more of the oxides of protein : it is probable that a portion of the fibrin of the blood undergoes a similar change, since these oxides are always present in arterial blood both in health and disease, especially in some forms of fever, when, by an accelerated respiration, a larger amount of oxygen is introduced into the system.\nFibrin and sulphuric acid.\u2014With strong sulphuric acid dry fibrin becomes yellowish and gelatinous, considerable heat being at the same time evolved, sufficient indeed, provided the quantity be large, to cause complete decomposition, when it blackens, and sulphurous acid is given off. When water is added, the gelatinous mass contracts suddenly in bulk, and the white curdy matter thus obtained consists chiefly of sulphoproteic acid, already described.\nFibrin and nitric acid. \u2014 Fibrin behaves with nitric acid in a similar manner to protein, giving rise to the formation of xanthoproteic acid.\nFibrin and acetic acid. \u2014When treated with concentrated acetic acid, it almost immediately becomes gelatinous, and if water be added and the mixture warmed, it readily dissolves, especially if the fibrin be obtained from a young animal : this solution when evaporated leaves the fibrin with precisely the same properties which it had previous to dissolution. If an-\nother acid, as the sulphuric, be added to the acetic solution, it combines with the protein, forming generally an insoluble compound, as in the case of the sulphobiproteic acid. If the acetic acid solution be neutralized with potash, the fibrin is precipitated, but is redissolved if the alkali be added in excess.\nFibrin and hydrochloric acid. \u2014 When treated with strong hydrochloric acid fibrin becomes gelatinous, and gradually dissolves,giving the solution a beautiful blue colour, which is characteristic of all the protein compounds : if this solution be diluted with water, a white precipitate appears, which is a compound of hydrochloric acid and protein. When the acid is very dilute it has the property of gradually dissolving fibrin ; and as a trace of free hydrochloric acid is generally to be found in the stomach, it is probable that its solvent action tends to assist materially in the process of digestion. Bouchardat says that water containing only one two-thousandth of its weight of hydrochloric acid causes moist fibrin to become gelatinous, and eventually to dissolve, leaving only a small quantity of insoluble matter, which he calls epidermose: the soluble portion he has called albuminose, but Mulder considers it binoxide of protein, which assertion, however, has recently been contradicted by Liebig.\nFibrin and potash.\u2014Fibrin dissolves readily in a solution of potash, even when very dilute. If the solution be gently heated, the fibrin is gradually decomposed, the sulphur and phosphorus being removed, and protein remains combined with the potash, from which it may be separated by neutralizing with acetic acid. Ammonia behaves in a similar manner, but its action is much less rapid.\nFibrin readily dissolves in the gastric juice, which appears to owe its solvent action both to the organic principle pepsine, and also to a little free hydrochloric acid in the stomach, which is derived from common salt. The same effect may be produced artificially by an infusion of the fourth stomach of the calf, to which a little hydrochloric acid has been added.\nIt is curious that the presence of certain salts, as nitrate of potash and sulphate of soda, prevents the coagulation of the fibrin of the blood ; and even when coagulated, provided it be still moist, it is again dissolved by some saline solutions, as, for instance, muriate of ammonia. Moreover, M. Denis has found that if mpist fibrin be digested in a solution of nitrate of potash containing a little soda, at a temperature of about 100\u00b0, it becomes gradually converted into a substance in almost every respect identical with albumen, being soluble in water, and coagulable by heat. This change is most readily produced when the fibrin employed has been obtained from venous blood, by allowing it to coagulate spontaneously ; while if it^jpe separated by agitation, or if the blood be arterial, it scarcely experiences any alteration in the saline solution. Changes of this kind, of the several modifications of protein into one another, are constantly occurring in the animal economy, and the great similarity","page":166},{"file":"p0167.txt","language":"en","ocr_en":"PROTEIN.\n16?\nof their composition must render such metamorphoses comparatively easy.\nThe composition of fibrin is C400 HS10 n,\u201e oISO sp, or ten equivalents of protein united to one of sulphur and phosphorus. It also usually contains from 1*3 to 2*3 per cent, of inorganic matter, chiefly phosphate and sulphate of lime, and alkaline salts.\nAlbumen. \u2014 This important compound, so called from its constituting the solid matter of white of egg, exists in two conditions, perfectly distinct in physical properties from each other ; the one soluble and miscible with water in all proportions, as it is found in the serum and white of egg ; the other solid, and quite insoluble in water, as in white of egg after boiling. The solid form is also met with, in a somewhat modified condition, in the albuminous tissues of the body, as the brain, spinal cord, nerves, &c. The proportion of albumen contained in some of the animal products may be seen in the following table.\n100 parts.\tAlbumen.\nBlood of ox .......................... 18*6\n\u201e\thog ....................... 18-58\n\u201e\tgoat ...................... 19-28\n\u201e\tsheep...................... 18*35\nEast India isinglass ......... 7*2 to 13 5\nEgg, white of ........................ 15*5\n\u201e yolk of......................... 17*47\nLiver of ox, parenchyma of .......... 20*19\nSweetbread (thymus) of calf........... 14*0\nMuscle of beef......................... 2*2\n\u201e\tveal......................... 3*2\n\u201e\tpork.......................   2*6\n\u201e\troedeer ..................... 2*3\n\u201e\tpigeon....................... 4*5\n,,\tchicken ..................... 3*0\n\u201e\tcarp......................... 5*2\n\u201e\ttrout ....................... 4*4\nBrain.................................. 7*0\nOptic nerve ........................   22*0\nAlbumen, in a state of absolute purity, has been but imperfectly examined. It may be prepared by the following process, recently adopted by Wurtz. A quantity of white of egg is well beaten up with about twice its bulk of water, and strained through linen to separate the cellular membrane. A solution of subacetate of lead is cautiously added, which throws down a copious precipitate ; but care must be taken to avoid adding an excess of the precipitant, which would partly redissolve it. The precipitate should be well washed, and while suspended in water a stream of carbonic acid passed through it : the liquid soon becomes frothy, owing to the decomposition of the albuminate of lead and liberation of free albumen, carbonate of lead being precipitated. The solution of albumen, after filtration, generally contains a trace of oxide of lead, which may be separated by adding a few drops of solution of sulphuretted hydrogen, and warming the liquid till it just begins to coagulate, when the whole of the sulphuret of lead is entangled in the coa-gulum: the liquid, which after another filtration is clear and transparent, should be cautiously\nevaporated at a temperature not exceeding 120\u00b0, when it leaves a residue of pure albumen.\nAlbumen thus prepared is brittle, semitransparent, without taste or smell, and almost colourless. When burnt it leaves avery minute quantity of inorganic residue, which seems to be quite free from alkali : this fact is important, as it tends to settle a question which has been long disputed, viz. whether pure albumen is really soluble in water, or whether its solubility is due to the free alkali with which it is usually associated. If dry albumen be digested with water in a moderately warm place it readily dissolves, but a small insoluble residue always remains. According to Wurtz a solution of pure albumen begins to coagulate when heated to about 140\u00b0 ; but if it be perfectly dry it may be raised to 280\u00b0 or 290\u00b0 without losing its solubility. It appears to have a slightly acid reaction, and if digested at a gentle heat, with a solution of carbonate of soda, it displaces the carbonic acid and combines with the soda. The albumen contained in white of eggs is composed of C400 H310N600120 SP, or ten equivalents of protein plus one equivalent of sulphur and phosphorus ; while that obtained from the serum contains an additional equivalent of sulphur, or C400 H310 Nso 0120 S2 P. It is usually associated with from two to five per cent, of inorganic salts.\nThe appearances presented by albumen with reagents are in most cases very similar to those of protein, which I have already described, and its solution in hydrochloric acid has the characteristic blue colour. Most of the acids precipitate it from its solution, but this is not the case with tartaric, acetic, and tribasic phosphoric acids. Hence nitric acid is often used to detect albumen in the secretions. Another delicate test for albumen is ferrocyanide of potassium, which gives a white precipitate even with acid solutions ; the ferridcyanide of potassium gives a yellowish precipitate. The application of heat is also a good test for this principle: but as the presence of free alkali tends to prevent its coagulation, it is always advisable to add at the same time a drop or two of nitric acid, when, if both cause a precipitate, the presence of albumen may be considered certain: it must be remembered too that the presence of those acids which do not precipitate albumen, such as the tribasic phosphoric, tartaric, and acetic, also interferes with its coagulation by heat. Many of the metallic salts, when added to albumen, form insoluble precipitates, which are in most cases compounds of albumen with the acid or the base of the salt. A drop of a solution of bichloride of mercury will thus indicate the presence of albumen, even when diluted with two thousand times its weight of water; and this property of forming an insoluble compound has been taken advantage of in the treatment of cases of poisoning with the bichloride, when the white of egg has been found of great service ; the white of one egg being sufficient, according to the experiments of Peschier, to neutralize the effects of four grains of the poison. Albumen is precipitated from its solutions by many\nm 4","page":167},{"file":"p0168.txt","language":"en","ocr_en":"168\nPROTEIN.\nother substances, as tannic acid, creosote, alcohol, and ether ; and its coagulation may also be effected by a current of voltaic electricity. When taken into the stomach it is coagulated by the free acid usually present.\nThe curious change which albumen undergoes from the soluble to the insoluble condition is but very imperfectly understood, and it is not known how far the physical state of that coagulated by heat resembles that rendered insoluble by alcohol and the other pr\u00e9cipitants. It is said that if an egg be smeared with oil immediately after it is laid, and afterwards exposed to heat, the coagulation is incomplete. Coagulated white of egg readily dissolves in alkaline solutions, and is reprecipitated unchanged if the solution be supersaturated with sulphuric acid. If it be digested at a temperature of about 120\u00b0, with a tolerably strong alkaline solution, the sulphur and phosphorus are separated from the protein; but if the alkaline solution be boiled, further decomposition takes place ; ammonia is given off, and leucin, protid, and other compounds are formed. If the alkaline solution in which white of egg is boiled be rather weak, it acquires, after some hours\u2019 boiling, a smell precisely similar to that of boiled fowl. Though perfectly insoluble after coagulation, both in cold and boiling water, it appears to dissolve when heated under pressure to about 300\u00b0 with that liquid, and the solution thus formed behaves in every respect similar to uncoagulated albumen. When exposed to the air in a moist state albumen is extremely prone to enter into putrefaction; but if dry it may be preserved unchanged for any length of time. If boiled for several hours in water it is converted into tritoxide of protein, without passing through the intermediate stage of binoxide, in which respect it differs from fibrine.\nThe ready convertibility of albumen into the other protein compounds, as well as into many other animal tissues, is well illustrated in the phenomena of incubation ; where we find all the various compounds which are contained in the hatched bird, derived more or less directly from this substance, which, together with a yellow oil and some inorganic salts, constitutes the whole of the solid contents of the egg.\nCasein is the form in which protein appears in the milk, where it constitutes the chief source of nourishment to the young animal, for which purpose it is admirably adapted, not only from the protein it contains, which is readily converted into fibrin and albumen, but also on account of the inorganic salts, especially phosphate of lime, with which it is always associated. The proportion of casein contained in the milk of different animals varies considerably; and a still more striking variation is caused by the food of the animal, as may be seen in the following table.\n100 parts.\tCasein.\nCow\u2019s milk ............................ 4\u201948\n\u201e fed on hay ........................ 3\u20190\n\u201e\t\u00bb\tturnips .................. 3 0\n\u201e\t\u00bb\tclover ................... 4*0\n100 parts.\tCasein.\nCow's milk potatoes and hay, 3*3 to 5*1\nEwe\u2019s milk ........................... 4\u20195\nGoat\u2019s milk ............................ 4\u201902\nAss\u2019s milk.......,,................... 1*82\nWoman\u2019s milk............................ 1\u201952\nCasein is scarcely known in a state of absolute purity, as it is extremely difficult to separate it entirely from inorganic impurities : these consist chiefly of lime, potash, soda, and iron, combined with phosphoric, sulphuric, and hydrochloric acids. The purest specimens prepared by Rochleder left, when burnt, only 0*3 per cent, of incombustible ash ; but as it is generally prepared it contains considerably more, sometimes as much as 10 per cent. It appears to be insoluble in water, and owes its solubility in milk to the small quantity of potash which is always present. The best process for obtaining casein is the following. A quantity of milk is first evaporated to dryness on a water-bath, and the dry residue, reduced to powder, is boiled in successive portions of ether until the whole of the fatty matter is removed ; the impure curd should then be evaporated to dryness, and the soluble part separated by digesting in water. To this solution, after filtration, alcohol is added to throw down the casein, which, however, is often still contaminated with a little sugar of milk : this may be removed by again dissolving in water, and once more precipitating the casein by alcohol. When dry it resembles albumen very much in appearance, and its behaviour with reagents is in most cases very similar ; it differs from it chiefly in not coagulating when heated, and it is precipitated by all the acids, but redissolves in an excess of most of them. Sulphuric acid throws down a compound which has been called sulphate of casein; this precipitate always contains a certain quantity of phosphate of lime, and it is only by repeatedly dissolving it in an alkaline solution, reprecipitating with dilute sulphuric acid, and well washing with boiling water, that it can be obtained in a state of purity. When milk or a solution of casein is heated under ordinary circumstances, a thin skin is formed on the surface, which, if removed, is quickly replaced by another; this substance has never been properly examined ; but as it is not formed unless oxygen is present, it is probably the result of oxidation. Casein is precipitated from its solutions by ferrocyanide and ferridcyanide of potassium, provided the solution is not alkaline, and still more perfectly if a little acetic acid is present. Lactic acid also readily coagulates casein; but the coagulation appears to be most completely effected by the lining membrane of the stomach of the young animal, an action due either to lactic acid, or, what is perhaps more probable, to the presence of pepsine.\nCasein has been found in some of the animal fluids besides milk : the saliva, the bile, pancreatic juice, and perhaps the blood, all contain it in more or less notable quantity. It affords another instance of the admirable adaptability of this interesting class of compounds","page":168},{"file":"p0169.txt","language":"en","ocr_en":"PROTEIN.\nvery similar to that already mentioned when speaking of albumen: in the milk, which is the sole food on which the young of most animals subsist, no other protein compound has been detected ; but no sooner has it become the food of the young animal which it is intended to nourish, than it is for the most part converted into fibrin and albumen, thus furnishing blood and muscle, together with most of the other tissues of the body, which, though less directly, are scarcely less certainly products of the decomposition of this substance. The composition of casein is represented by the for-mula C400 H310 Nso 0120 S, or ten equivalents of protein united to one equivalent of sulphur, thus differing from fibrin and albumen in not containing any phosphorus.\nThere is another modification of protein, very similar to casein in its properties and composition, which has been called both globulin and crystalline, from the circumstance that it is found surrounding the blood globules and also in the crystalline lens of the eye. It appears to contain no phosphorus and less sulphur than casein, and is composed, according to Mulder, of fifteen equivalents of protein united to one of sulphur.\nThe form in which protein exists in hair, horn, nails, and the epidermis, and called by Simon keratine, has been but imperfectly examined. That these substances are composed chiefly of protein is proved by the circumstance that if a solution of them be made in caustic potash and neutralized with acetic acid, a copious precipitate of protein is thrown down. It is probable that other modifications of protein will hereafter be found to exist in the animal body, but those which I have now described are all which have hitherto been detected.\nThe animal body, however, is not the only source from which protein and its compounds are to be obtained. The researches of modern chemists have led to the interesting fact that they exist in the vegetable kingdom also, and that they are there so extensively disseminated that not a leaf, a seed, or a twflg, in any of the various tribes of plants, is free from them ; and it is highly probable that the whole of the protein compounds constituting the bodies of animals are derived from plants. In the present state of analysis it is perhaps too much to say that the forms in which we find protein in vegetables are absolutely the same, with regard to the minute quantities of sulphur and phosphorus, as those found in animals ; but as far as we are able to judge from similarity of properties, we may safely divide them in the same way as the analogous animal principles ; viz. into vegetable fibrin, vegetable albumen, and vegetable casein. They all yield, when heated with strong hydrochloric acid, blue or purple solutions; and when they are digested with a solution of potash, and neutralized with acetic acid, protein is invariably produced.\nVegetable fibrin is found most abundantly in the seeds of the cerealia, as wheat, oats, &c. : it is also found dissolved in the juice of most plants, especially that of grapes, carrots, turnips, and beetroot, from which it shortly sepa-\n169\nrates in the form of a flocculent precipitate when taken from the plant and allowed to stand. The readiest way of preparing it is to knead wheaten flour into a paste with water, and then wash it on a linen cloth with a stream of cold water until the whole of the starch is removed, which is known by the water passing through quite clear : the viscous mass which remains on the cloth is subsequently purified by washing with alcohol and ether, in both of which the fibrin is insoluble. When dry it is a hard horny-looking substance, semitransparent, without taste or smell, and sufficiently heavy to sink in water, in which it is insoluble. Phosphoric and acetic acids readily dissolve it ; and it is reprecipitated in the form of white flocks from its acid solution by carbonate of ammonia and ferrocyanide of potassium, and yellowish by tincture of galls ; it is also precipitated by bichloride of mercury and some other metallic salts. It is perfectly soluble in solution of potash even when very dilute, and if the quantity of fibrin dissolved be large, the liquid loses its alkaline flavour.\nVegetable albumen is found to exist very abundantly in the juices of most plants, and still more so in nuts, almonds, and other oily seeds, where it is usually associated with casein. It may be easily recognized by boiling the expressed juice of any of the common culinary vegetables after the fibrin has separated, when it coagulates in a manner similar to animal albumen. It may be obtained in a tolerably pure state by boiling the filtered juice of any of the leguminosce, and washing the precipitate with alcohol and ether. It closely resembles animal albumen in properties, and is distinguished from vegetable fibrin by its solubility in water, and from vegetable casein by coagulating when heated.\nVegetable casein has also been called legu-mine, from the circumstance of its being found most abundantly in the leguminosce, though it is by no means confined to that tribe of plants: it is also present in considerable quantity in company with albumen in most of the oily seeds, and in the juices of most nutritious vegetables. It may be obtained by the following process. Peas or beans should be soaked in moderately warm water for some hours until they are sufficiently soft to allow of their being mashed in a mortar : the pasty mass is then mixed with a large quantity of water, which dissolves the casein, and thrown upon a cloth to filter. The starch passes through the filter together with the solution of casein, and if allowed to stand, gradually subsides to the bottom : when the liquid is clear, it is decanted by means of a syphon, and slightly supersaturated with acetic acid, which determines the precipitation of the casein in an impure state, but readily purified by washing with alcohol and ether. Vegetable casein resembles that obtained from milk in most of its properties ; gives the same insoluble skin when heated in contact with the air ; and is precipitated from its aqueous solution of alcohol and several of the metallic oxides : it is also thrown down by both vegetable and mineral acids, redissolving","page":169},{"file":"p0170.txt","language":"en","ocr_en":"170\nPTEROPODA.\nin an excess of the former, except the acetic, and insoluble in excess of the latter. If a solution of casein be allowed to stand some time, lactic acid is gradually formed, which causes it to coagulate, and putrefaction then begins, which, if any sugar is present, determines in it the alcoholic fermentation.\nThe various forms of protein which are found constituting the muscles, tissues, and solid matters of the blood of animals, are thus evidently derived from the vegetable kingdom ; that silent but ever active laboratory in which so much of the chemical economy of nature is carried on. From the gaseous matters of the atmosphere, more especially carbonic acid, ammonia, and watery vapour, the organic elements, carbon, oxygen, hydrogen, and nitrogen, are derived ; and from the various saline ingredients of the soil, those inorganic substances which are essential to the growth and well-being of mankind and of the lower animals are readily abstracted by the absorbent fibres of the roots. Thus formed, plants constitute the source from which all living beings obtain the nourishment which is necessary to their existence, and of which the very substance of their bodies is composed ; an arrangement which is most strikingly evident in the herbivora, because vegetables are their only food, but not less certainly in the carnivora, since the animal flesh which they consume is either that of the herbivora or of some animals which have fed upon them.\nIt is impossible not to admire the simplicity which pervades the whole of this vast scheme, in which we find so large a portion of the animal body composed of materials almost identical in composition, though differing so essentially in their use and applications. If one of these principles, albumen or casein for instance, be contained in the food in quantity insufficient for the requirements of the animal, it is readily supplied from one of the others by the addition or removal of a minute quantity of sulphur or phosphorus, both of which are always present ; whereas, if this beautiful provision \"had not been made, a large amount of disease and suffering would have almost necessarily ensued. Moreover, had the task of elaborating these highly complex principles from more simple ingredients devolved on animals themselves, much complicated machinery would probably have been required, which would have added unnecessarily to the complexity of the body, and consequently to the sources of physical derangement.\n[Since the above has been in type, some researches, which are still in progress, have thrown a doubt upon the exact composition of protein, and indeed rendered it uncertain whether it can be obtained in a state perfectly free from sulphur.]\nBibliography. \u2014 The following books may be mentioned as containing the fullest descriptions of protein and its compounds, together with other branches of physiological chemistry :\u2014Simon, Handbuch der angewandten medizinischen Chemie, of\nwhich a translation has been published by the Sydenham Society. Liebig, Trait\u00e9 de Chimie organique, tom. i. & iii. Liebig's Animal Chemistry, translated by Gregory. Mulder, Chemistry of vegetable and animal physiology, translated from the Dutch by Fromberg ; and Dumas, Trait\u00e9 de Chimie appliqu\u00e9e aux arts, tom. vii. & viii. Besides these many detached papers of great value will be found in the later volumes of the Annales de Chimie et de Physique ; Annalen der Chemie und Pharmacie, by Liebig and Wohler ; Poggendorff\u2019s Annalen der Physik und Chemie; Philosophical Transactions, Philosophical Magazine, &c.\n(J. E. Bowman.)\nPTEROPODA (Gr. irrepov, a wing, irons, a foot; Fr. Pteropodes; Lat. Mollusca pin-nata).\u2014An order of Molluscous animals established by Cuvier, and named in accordance with his arrangement of the Molluscous division of the animal kingdom, from the position of their organs of locomotion, which in the creatures we are about to examine is very remarkable. All the animals belonging to the order are marine, and in some regions of the ocean crowd the surface of the sea at certain seasons in immense numbers, swimming by the aid of two muscular expansions resembling fins, which are attached to the opposite sides of the neck, and serve as paddles, although, in the language of Natural History, named feet.\nNotwithstanding the multitudes of individuals belonging to this group, which are said to swarm both in the polar regions and in tropical climes, the number of genera at present ascertained to exist is very limited, and such is their minute size and the delicacy of their structure, which precludes the possibility of studying them, unless in a fresh state, that, up to a very recent period, their anatomy was imperfectly understood, and, doubtless, much remains yet to be achieved by those who may be favourably situated or investigating them more closely.\nThe characters which they present in common, and by which they are separated by naturalists as a distinct group of Mollusca, are the following: \u2014 Their bodies are free, and organized for natation ; they are furnished with a distinct head, but possess no locomotive organs, except a pair of lateral fins.\nGenera.\nClio {fig. 108).\nHyalea {fig. 114).\nPneumoderma {fig. 115).\nCymbulia.\nLimacina.\nCleodora.\nAtlanta.\nM. d\u2019Orbigny, in a memoir read before the Academy of Sciences in Paris*, gives some interesting particulars relative to the organization and habits of this remarkable class of molluscous animals. They are met with in all seas, under the equator as well as in the\n* Vide Ann. des Sciences Nat. for 1835, p. 189.","page":170},{"file":"p0171.txt","language":"en","ocr_en":"PTEROPODA.\n171\nvicinity of the polar circle ; and, being eminently constructed for a pelagic life, never approach the shore. They are all, moreover, nocturnal or crepuscular, voyagers agreeing that they are never to be seen during a clear day when the sun shines brightly ; but towards five o\u2019clock in the evening, when the weather is cloudy, two or three species begin to make their appearance at the surface of the water, generally belonging to the genus Hyalea.\nAs soon as twilight begins, large quantities of small Cleodor\u0153, Hyale\u0153, and Atlantes may be caught ; but the larger species only come to the top when night has set in ; at which time only the Pneumodermas, the Clios, and the large Cleodorce can be procured. Certain species indeed only approach the surface on very dark nights, as, for example, the Hyalea balantium. Very soon all the smaller species again gradually disappear, as do the large ones a little later, and towards midnight a few stragglers only of different kinds are to be met with. At sunrise not a single Pteropod is to be seen, either at the surface, or at any depth to which the eye can penetrate. Each species, in fact, seems to have its appropriate hours, or rather its appropriate degrees, of darkness.\nM. d\u2019Orbigny supposes, from these habits, that each species lives at a certain depth in the water which is proper tp it, and where it is consequently exposed to a diminution of light proportionate to its distance from the surface. Every species, therefore, will only come to the top at that period of the twenty-four hours when the obscurity approximates to that to which it is accustomed in its usual situation while the sun is above the horizon, mounting gradually upwards as the light of day diminishes. If the Pteropoda remained all night at the surface of the sea, there might be reason to think, as M. Rang supposed, that they ascend at sunset for the purpose of obtaining food or fresh air in the most superficial strata of the ocean ; but as these could be procured at all hours, it seems more probable that it is the light which thus regulates their movements.\nThere is reason to suppose that each species of Pteropod remains during the whole year in the same regions of the ocean. These regions are of different degrees of extent, and currents doubtless tend to enlarge their boundaries ; probably to this cause must be attributed the extensive diffusion of certain species met with in all climates ; whilst others of larger size are only found in the torrid zone, and others again of equal dimensions are peculiar to cold climates.\nA table appended to the Memoir of M. d\u2019Orbigny assigns the limits between which each species has been found, and its nocturnal or crepuscular habits. From this table it appears, that of twenty-nine species of Ptero-pods known to the author, fourteen are met with both in the Atlantic and Pacific oceans, whilst eleven are proper to the Atlantic and four to the Pacific ; of these seventeen are\naltogether nocturnal in their habits, and only eleven crepuscular.\nThe Pteropoda swim in a very peculiar manner. Their cephalic fins are only able to support them by a constant repetition of rapid movements, resembling those of the wings of a butterfly. These fins are kept in motion continually ; and, according to the direction of their stroke, the animal advances horizontally, or mounts or descends, the body remaining all the time either in a vertical position or slightly inclined. Sometimes they keep spinning round without changing their place, or even keep at a certain height in the water without any apparent exertion ; but this power of remaining motionless has only been observed in a small number of species, the butterfly-movement of the wings being most commonly resorted to. If while they are thus in motion, the appearance of any strange body or even a sudden shock given to the vessel in which they are contained, causes them alarm ; their wings fold upon their bodies, or in some species are entirely withdrawn into their shell, and the animal sinks rapidly to the bottom of the vessel. Most probably, when at liberty, as soon as the creature has sunk to a sufficient depth to ensure safety, it again unfolds its wings, and sustains itself in the water instead of allowing itself to go quite to the bottom.\nThe Hyalea and Cleodora swim with the greatest rapidity, in Pneumoderma and Clio the movements are less vivacious.\nThe larger Pteropods seem to feed principally upon smaller species of their own class, as well as upon the minute crustaceans that swarm in the seas they frequent.\nClio. Integument. \u2014 The skin of the Clio is not smooth, but studded with numerous little wart-like eminences, causing a roughness, which is in direct relation with the red colour of the integument, and is consequently most conspicuous near the extremity of the tail. Both the roughness and the red colour indeed are produced by the presence of a multitude of little cavities or sacculi filled with an oily red pigment, the pointed ducts of which project externally. These pigment-sacs are not only most abundant near the extremity of the tail, but in that part of the body are of larger size than elsewhere : they are all flask-shaped, opening upon the surface of the body by a narrow neck, while their larger extremity is imbedded in the subcutaneous cellular tissue. Beneath these larger pigment-sacs smaller ones of a similar description are perceptible, much smaller in their dimensions than the preceding, and in many places where the larger ones are deficient, the smaller pigment cells are proportionately more numerous : both kinds are filled with the same oillike colouring material, and are apparently comparable to simple mucous follicles, only their secretion is of a more oily character.\nWith the exception of the pigment cells, the integument of the living Clio is quite transparent, but after being kept in spirits of wine, its transparency is considerably diminished ; in its","page":171},{"file":"p0172.txt","language":"en","ocr_en":"172\tPTEROPODA.\nsubstance, muscular fasciculi are perceptible, the direction of which is principally towards the crucial muscles of the fins. Upon the dorsal region of the body, these tegumentary muscles first become distinct at the transverse constrictions above referred to. These constrictions disappear as soon as the skin is cut through, and the inner layers of the dorsal region then appear quite lax. In this way, indeed, the existence of transverse fasciculi of cutaneous muscles is rendered evident, even when their presence cannot be proved by direct observation.\nIn many places, the cutaneous muscles are still more complex in their arrangement, more particularly in the neighbourhood of the eyes. In the head, and partially also in the neck, where a firmer connexion between the skin and the general muscular strata of the body exists, an expansion of the proper cutaneous muscles is with difficulty to be demonstrated.\nFig. 108 (1 to 6).\n1.\tClio Borealis, seen from the ventral aspect, the head-cowls shut together.\n2.\tThe same ; the head-cowls turned hack, and the cephalic and generative apparatus displayed.\n3.\tDetails of ditto.\n4.\tClio borealis with the head cowls closed, seen from the dorsal aspect.\n5.\tSide view (right) of the same, the fins cut off at their roots.\n6.\tDetails of ditto.\t(After Eschricht.')\nThe nerves of the integument are easily traced in fresh specimens on account of the transparency of the skin. The most conspicuous are two large cutaneous nerves running on each side of the body, which ramify upon its lateral and ventral aspects.\nImmediately beneath the skin is a layer of cellular tissue, which is very different in different regions. In the hinder part of the body it exists in great abundance, and in it, as already stated, the large pigment cells are imbedded, so that in this region the skin is very easily separated from the muscular strata beneath. It is most abundant likewise in the region of the heart where the urinary bladder is situated. In the fins, this cellular membrane is more scanty, and in the regions of the neck and head, it is so dense that here the skin can only be raised with difficulty. In specimens that have been kept in spirits, the subcutaneous cellular tissue is very generally infiltrated with fluid so as to give the appearance of a cavity existing beneath the integument, the boundaries of which are circumscribed by those parts where the skin is most adherent to the subjacent tissues, or where the cutaneous muscles interlace with each other.\nMuscular system. \u2014 The muscles of the Clio borealis are chiefly disposed in a single layer, situated beneath the subcutaneous cellular tissue, that encloses the whole hinder part of the body as in a bag, which, however, in the region of the neck and of the head, spreads out into separate fasciculi of muscle. This muscular bag is described by Cuvier* as being composed of very conspicuous longitudinal fibres, derived from two principal fasciculi attached to the sides of the neck, the effect of which will be to shorten the whole body, and make it assume a form approximating to the spherical. In fresh specimens preserved in spirits, the muscular bag in question is easily visible through the skin ; but in the living animal, it is most likely itself transparent, and in old specimens cannot be seen on account of the opacity of the external integument. The muscular fibres composing this sheath, do not by any means run straight and undivided from behind forward, but, on the contrary, interlace with each other, so as to form an expansion in which the longitudinal fibres are the most conspicuous. From the neck forwards, these muscular bands become more precise in their arrangement. At the sides of the body, they separate from each other so as to leave a space both behind and in front, in which the muscular layer is deficient; the dorsal and ventral fasciculi becoming more and more detached as they advance forwards, leaving a wide opening in the muscuter sheath, which near the head gives passage to the lateral fin, and behind this for the pair of large cutaneous nerves, also on the right side, close to the fin, for the common opening of the male and female generative apparatus, and, a little behind the exit of the two cutaneous nerves, for the anus. In its posterior corner lies the pericardium also on the right side but more deeply situated.\nThese different parts, as they issue through the muscular opening of the right side, are further embraced by muscular fasciculi, which\n* Memoire sur le Clio, p. 6.","page":172},{"file":"p0173.txt","language":"en","ocr_en":"PTEROPODA.\t173\nrun transversely from the dorsal to the ventral aspect of the body bounding and separating their orifices.\nLocomotive Apparatus.\u2014The locomotive apparatus of the Pteropoda is constructed upon most peculiar principles, consisting of a pair of fin-like expansions attached to each side of the neck of the animal.\nThese fins, or, as they are commonly called, wings in the Clio have a very remarkable structure, the two being continuous with each other, through the intervention of a central part, which extends transversely across the neck of the animal, so that the lateral expansions are\nonly the free extremities of the same organ, the whole apparatus representing, with curious exactness, the double paddle used by the Greenlanders in navigating their light double-pointed canoes (Kajaks). The entire apparatus is muscular, and consists of two layers, precisely similar in their structure, which, at their margins, overlie each other, but are only connected together by means of cellular tissue. The course of the muscular fibres is shown in the annexed figure, representing the whole of the swimming apparatus removed from the body; in which the following parts may be distinguished : \u2014- a, the anterior or\nFig. 109.\nClio Borealis.\nSwimming apparatus detached. (After Eschricht.)\ndorsal margin ; b, the posterior or ventral excavation ; c c, the posterior, transparent, triangular lappets which bound the fin ; d d, the posterior outer border ; e e, the posterior inner border ; o, the central portion which traverses the neck ; m m m mt commencement of the free portions of the fins.\nIn the cellular membrane interposed between the two muscular layers of the fin apparatus, four or five large nerves are seen to run a tortuous course, and to divide into innumerable fibrill\u00e6. Eschricht likewise observed a considerable blood-vessel derived from the ventricle of the heart (notfrom the auricle), mounting up and dividing to supply each fin.\nRespiration and Circulation. \u2014 According to Cuvier\u2019s views the fins of the Pteropoda have been very generally regarded as performing likewise the functions of branchi\u00e6. \u201c Their surfaces, seen with the microscope, present a net-work of vessels, so regular, so close, and so delicate that it is impossible to doubt their office : their connection with the internal vessels and the heart, moreover, confirms this idea.\u201d * Cuvier\u2019s opportunities of investigating this point of their anatomy were, however, very limited ; a single specimen only, and that long kept in spirits of wine, having been at his disposal. Eschricht\u2019s researches do not at all confirm this view of their nature ; and it appears clear that Cuvier mistook the network of muscular fibres represented in the preceding figure for vascular ramifications.\n* Cuvier, Mem. sur le Clio.\nThe vessel likewise called by Cuvier \u201c the branchial vein,\u201d and which he regarded as returning the blood from the branchi\u00e6 to the auricle of the heart, Eschricht assures us, does not communicate with the auricle, but is derived from the apex of the ventricle so as to be evidently arterial, and not venous, in its nature.\nWith regard to the connexion which exists between the fin-apparatus and the body of the Clio, it would appear that its central muscular basis passes directly through the neck, and is only attached to the surrounding parts by nerves, vessels, skin, and cellular membrane.\nNervous system.\u2014The nerves of the Clio are very easily traced, seeing that they are not only of considerable size, but are likewise conspicuous, on account of their pale red colour, at least while the specimens are tolerably fresh.\nThe oesophageal ring lies in the neck above the centre of the fin-apparatus, and lodged in its dorsal excavation. It is composed of eight large and two small ganglia. Each ganglion is surrounded by a transparent investment, and is very evidently composed partly of a reddish and partly of a white nervous substance. Of the eight larger ganglia of the circum-\u0153sophageal ring the two anterior (fig. 113. 30, 1) are situated close together, upon the dorsal aspect of the oesophagus ; the two posterior (fig. 113. 30, 4) are likewise close together, but beneath the oesophageal tube. Of the four intermediate ganglia, two are situated close together on each side of the oesophagus (fig. 113. 30, 2, 3), so that when viewed","page":173},{"file":"p0174.txt","language":"en","ocr_en":"174\nPTEROPODA.\nsuperficially, either from the dorsal or ventral aspect, they have the appearance of forming one elongated mass. By means of a nervous band which connects them, the eight ganglia form a double ring, seeing that the two lateral pairs of ganglia are, as well as the inferior, brought into communication with each other through the intervention of a cross branch which runs beneath the oesophagus.\nIn addition to the eight ganglia above mentioned there are likewise two small nervous masses {fig. 113. 30, 5), situated one on each sidepf the anterior pair, with which they are connected by short nervous branches.\nAll the nerves given off from these centres seem to proceed from the ganglia nearest to their place of destination. From the anterior pair are derived all the nerves supplying the parts of the head and the eyes. From the lateral pairs the nerves of the fins are principally given off, while the posterior pair furnishes nerves to all the hinder parts of the body.\nEyes. \u2014 The eyes in Clio are situated upon the dorsal aspect of the body, in the constriction which constitutes the neck. In this situation the skin is drawn deeply around them, so that they seem to be lodged in special depressions appropriated to receive them. Each eye {fig. 113. 31) has somewhat the shape of a bent cylinder, the two ends of which are of a spherical form. The external spherical extremity of this eye, which is transparent, and constitutes the cornea, stands prominently above the level of the skin. By transmitted light it is not difficult to distinguish the construction of the interior. The middle third of the cylinder is generally of a dark colour, whilst the anterior and posterior extremities of the cylinder are comparatively transparent ; but, probably, in the recent animal, the dark pigment extends back as far as the hinder end \u2014 anteriorly, it is easy to perceive the existence of a transparent lens ; but from the small size of the organ, it is difficult to make out their structure more completely. In connexion with these eyes, delicate muscular fasciculi may be traced radiating in different directions, which would seem to have the office of turning the eye-ball towards any particular object.\nThe only other special organs of sensation possessed by the Clio are the tentacula ; but these will be best described in connexion with the head to which they are appended.\nHead-cowls and Tentacula. \u2014 The structure of the head of Clio is very remarkable ; and, in its general characters, cannot be more appropriately described than in the words of Pallas.* \u201c Caput contractual subgloboso-didymum est, lobo vel utroque vel a\u00efterutro, imo quandoque neutro, antice papilla carne\u00e2 {tentaculum) acut\u00e2, mucronat\u00e2. Qui lobi sunt proprie pr\u00e6putia duo {the head-cowls) crassa, carnea ; hemisphaerica, contractilia, basi coad-unata, e quorum interiore latere emergunt tentacula {head-cones) tria carnosa, conica,\n* Spicelegia, x. p. 28.\n\u00e6qualia qu\u00e6 ori utrinque adstant et contracta in pr\u00e6putio tota delitescunt.\u201d\nFig. 110 (8 to 13).\nAnatomy of Clio.\n9.\tTransverse section of the ventral fasciculi, as they pass through the nerve surrounded by the muscular collar (V).\n10.\tHead of Clio, with the cowls half expanded, showing the conical cephalic appendages (s), and one of the tentacula (k) protruded.\n11.\tHead of Clio, cowls closed, and the left tentacle protruded.\n12.\tThe same seen from above.\n13.\tThe same, the cowls being widely separated so as to display the opening of the mouth.\n(After Eschricht.)\nThe above description will, however, be better understood by a reference to the accompanying figures, in which the structures above mentioned are delineated on a large scale. In fig. 110. 11 the head is represented, seen from the ventral aspect with the head-cowls {a, b) closed together, concealing all the other organs except the tentacula, one of which (k) is seen protruding through an opening in the left cowl, that of the opposite side being retracted\u2014 while in fig. 110. 10 the head-cowls are shown partially folded back, so as to display the conical appendages (head-cones) which the cowls enclose and protect.\nEach of the cowls {lobi, Pallas ; bucc\u00e6, Fabricius) seems, when more closely examined, to be composed of two spherical parts intimately conjoined, of which the anterior {fig. 110. 11, a a) is the smaller, and the posterior {b b) the larger. The posterior spherical portions are continuous with each other ; they enclose a large cavity, which is, in its widest part, filled up by the penis ; but, in its narrower and median part, contains the parts of the mouth \u2014 the oesophagus and the salivary apparatus. The smaller or anterior spheres, on the contrary, are only produced by the folding of the skin over the head-cones, and disappear when these organs are protruded. In the fore part of each of the anterior spherical portions of the cowl is a little flat surface, in the middle of which may be observed","page":174},{"file":"p0175.txt","language":"en","ocr_en":"PTEROPODA.\n175\neither the tentacle (fig. 110. 10 and 11,\u00a3), or the orifice (y?g.llO. 12, l), through which it is protruded : the two flat surfaces are separated from each other when the cowls are closed by a longitudinal fissure (p), the margins of which form two prominent lips (o o).\nThe lateral tentacles (k) are cylindrical, smooth, and terminated by rounded extremities. They are hollow, and in their interior, three longitudinal bands of muscle and a nerve of considerable size are distinguishable, so that they can be retracted in the same manner as the horns of a snail, nothing remaining externally to indicate their position, except the hole through which they are protruded. When thus inverted the tentacles are found lodged in the cavity of the head, with their apices directed inwards.\nThe two smaller spheres of the hood or cowl are separated from each other by the longitudinal fissure (fig. 110.11), which Fabri-cius, very inappropriately, called the mouth, although, at the same time, he was acquainted with the real mouth, and recognised it as such. This vertical fissure occupies the entire top of the head, and is continued for some distance both on its upper and under surface, or, more properly speaking, the real head is buried deeply in the interspace between the two cowls, and when these are separated from each other, the following parts are seen situated between them : in the centre of the floor of the fissure is the vertical opening of the mouth (fig. 110. 13, u), between which and the borders of the hood (q), are the crescentic spaces (r), in which are situated the conical appendages to the head already mentioned, and which are represented protruding from between the margins of the hood in fig. 110. 10 0).\nConical Appendages to the Head. \u2014 The conical appendages to the head (Kopfkegel, Eschricht), when fully expanded, form a kind of star round the mouth (fig. 108. 3, s), and were erroneously styled by Fabricius \u201c soft teeth\u201d (\u201c suntque dentes hi molles subcrus-tacei\u201d). It is to Eschricht we are indebted for a knowledge of the real nature of these wonderful organs, the structure of which is unparalleled in the animal creation. It has been already noticed that these conical bodies are of a red colour in the recent animal, and, when they are protruded, it is easily discoverable with a lens that this colour depends on the presence of numerous separate coloured points distributed over their surface. When still further magnified, these points show themselves as closely aggregated spots, arranged with great regularity upon the exterior of the cone. Upon a rough calculation there may be about three thousand of these spots upon each conical appendage, each of which, when closely examined, under favourable circumstances, assumes very much the appearance of the pol}7pe-cell of one of the Sertularian polypes, and exhibits a structure which is truly admirable. Each little spot consists, in fact, of a transparent sheath, enclosing a central body, composed of a stem terminated by\na kind of tuft, which last can be protruded at times beyond the margin of the sheath. When viewed laterally (fig. 111. 14) it is apparent that this central body consists of several filaments or tubes, every one of which expands at its extremity into a dilated portion, terminated by a little disc (fig. 111. 15), and about twenty of these are enclosed in each sheath. The conical appendages to the head of a single Clio are, therefore, furnished with (20X3000X6) about three hundred and sixty thousand of the stem-supported discs in question.\nFig. Ill (14 to 21).\nClio Borealis.\n14.\tOne of the 3000 prehensile organs with which each of the six conical appendages to the head is furnished. Magnified 300 diameters.\n15.\tAn isolated sucking disc from the above. Magnified 900 diameters.\n16.\tThe head and neck laid open by a longitudinal section, showing two of the conical appendages and the penis, in situ. Magnified 5 diameters.\n17.\tLongitudinal section of the head along the 'mesial line.\n18.\tto 21. Pharynx and oral apparatus. Magnified 7 diameters. (After Eschricht.)\nAs relates to the internal structure of these conical organs, Eschricht ascertained that they","page":175},{"file":"p0176.txt","language":"en","ocr_en":"176\tPTEROPODA.\nare hollow, and that their cavities communicate with the common cavity of the head : they have likewise their proper muscles, and each receives a large nerve derived immediately from the anterior supra-cesophageal ganglion. As to the use of this elaborate apparatus, there is still room for speculation. Captain Holb\u00f6ll, although he frequently observed them porrected, while the creature was swimming, never saw them employed as suckers or instruments of prehension ; nevertheless, it seems impossible to doubt that such is their real office, when we reflect upon their remarkable structure, and further take into account their situation, so completely analogous to that occupied by the sucking discs of the Cephalopoda, and still more closely resembling the cephalic appendages of Pneumoderma. It is, therefore, extremely probable that these, organs are employed for holding to foreign objects at the bottom of the sea, and that the great number of the sucking discs is in correspondence with the power possessed by the Clio of crawling about upon uneven surfaces.\nThe mouth of the Clio is a vertical fissure, that is easily displayed by slightly folding back the head-cones (fig. 110. 13, u). Its margins seem to enclose some calcareous substance, which, in specimens preserved in spirit, is of a chalky whiteness. Numerous muscular fasciculi surround this opening, which, when expanded, has somewhat of a triangular form, so that during life the mouth can be forcibly opened by the radiating muscular fasciculi that surround it.\nIn the cavity of the mouth there may be observed, on each side, a round fossa, in which can be seen projecting, even with the naked eye, a hard shining substance, first noticed by Pallas and Fabricius, who regarded these bodies as simple teeth. Closer inspection, however, reveals them to have a very curious structure, which is, perhaps, unique, each consisting of a bundle of about thirty gold-coloured, crooked, stiff and sharp hooks {fig. 112. 22, w), derived from a common base (x), and forming a pair of lateral jaws, wherewith the creature seizes its food.\nIn the middle of the ventral aspect of the cavity of the mouth there is, moreover, a prominent tongue-shaped organ, which, when moderately magnified, may be seen to consist of two lateral bands of a black colour, which are united in the middle line, and which are covered with an immense number of extremely minute teeth, that will be more particularly described hereafter. The pharynx, when examined from above, is somewhat lyre-shaped : it is composed of two lateral branches (fig. 111. 19, i), the posterior ends of which are joined by a convex central portion (z). The tube of the oesophagus is not prolonged immediately from its hinder extremity, but seems to arise from the hinder wall of the pharyngeal cavity (fig. 111. 17 and 21, e).\nThe nerves of the pharynx arise from two ganglia (fig. 111. 18, 20,?/) situated imme-\ndiately behind it, in conjunction with the anterior ganglia of the circum\u0153sophageal ring, and which inferiorly are connected together by strong branches of intercommunication and from which nerves radiate laterally to supply the surrounding parts. The thin ducts of the salivary glands (fig. 111. 17, 18, 19, and 20, g) terminate above these ganglia opening into the cavity of the mouth in the immediate vicinity of the tongue.\nThe pharynx, when viewed with a lens, and still more when examined under the microscope, resembles, very closely, the gizzard of a gallinaceous bird, the resemblance consisting in the great strength of its muscular parietes.\nEach lateral portion (fig. 111. IS, i) is a small curved cylinder, the outer wall of which is entirely muscular. The fasciculi are principally arranged in two layers, the fibres crossing each other. On opening one of these muscular capsules, by means of a fine pair of scissors it is found to contain, in its interior, a cylindrical body made up of several parts. At its anterior extremity are situated the lateral teeth above alluded to (fig. 111.19, and fig. 112. 22, v). These are arranged in parallel arches, in such a way that their points all attain the same height, notwithstanding the great difference in their length, the posterior (iexterior) tooth (fig. 112. 23, a) being far the longest ; while the an-\nFig. 112 (22 to 24).\nClio Borealis.\n22, 23 a, 23 b. Dental apparatus, magnified 28 diameters.\n24. Lateral view of the free portion of the tongue, magnified 130 diameters. (After Eschricht.')","page":176},{"file":"p0177.txt","language":"en","ocr_en":"PTEROPODA.\nterior (interior) (23, b) is the shortest of the series. The stem upon which these are fixed (22, w) is sloped off in the same proportion, and has a somewhat triangular shape. When crushed under the microscope, it is found to consist entirely of muscular fibres arranged with considerable regularity, and principally disposed in two opposite directions, so that they cross each other ; and doubtless a part of their office is to raise and depress the individual teeth, implanted upon the common stem. The hinder portion of the cylinders (x) containing this extraordinary dental apparatus, is muscular, and composed of longitudinal fasciculi, by the aid of which the stems that support the teeth are retracted, their protrusion being effected apparently by the construction of the capsules themselves. The manner in which the Clio makes use of these teeth may, therefore, be inferred from their anatomical arrangement. The cylinders wherein they are lodged are so much bent {fig. 111. 18, 19, \u00ab), that when the two dental organs of the opposite sides are protruded the apices of the teeth with which they are armed must meet together outside the mouth, and when in this condition the teeth of eaeh organ are widely separated and spread out, they will form, as it were, a couple of long combs (19, v), and evidently perform the functions of a pair of tenacious jaws.\nThe tongue may be divided into two portions; the one free, and the other fixed, studded with a number of hooklets that can scarcely be estimated at fewer than from six to eight hundred, the disposition of which at once indicates their office to be to facilitate the propulsion of the food into the oesophagus, as is the case in the Cephalopods and various other Mollusca.\nThe oesophagus is, for the greater part of its length, surrounded by the two salivary glands, which extend quite into the abdominal cavity, where they are connected to each other, and to the liver by lax cellular membrane. The stomach is a mere dilation of the oesophagus, and is entirely embedded in the substance of the liver. The latter organ appears, when examined superficially, to be entirely made up of a multitude of Acini, each of which contains within it a cavity that communicates through a wide aperture with the interior of the stomach; and hence it results, that, although the exterior of the liver is seemingly composed of large granules, the walls of the stomach are perforated all over with openings, leading into blind cavities, so as to have a completely cellular appearance.\nThe intestine is a simple tube, passing straight from the termination of the stomachal portion of the alimentary canal to the anal orifice, which is situated on the right side of th\u00e9 neck immediately behind the corresponding fin.\nThe course of the circulation in the Ptero-poda has not been as yet completely made out. In the Clio borealis, the heart enclosed in its pericardium is situated on the right side of the posterior end of the abdominal cavity just at\nVOL. IV.\n177\nthe point where the dorsal and ventral bands of muscle separate to form the wide lateral opening. The pericardium is pointed in front and broad behind : its walls are thin and transparent, but at the same time very strong. On opening the pericardium, the ventricle of the heart is seen to have the shape of a triangular pyramid with rounded angles, the apex of the pyramid being directed towards the head, whilst its base is turned towards the hind part of the body. From the apex of the heart arises a large vessel, which immediately pierces the pericardium, and supplies branches to the liver and to the internal organs of generation ; it then advances forward, and supplies the parts about the neck, more especially the lateral fins, and most probably is ultimately distributed to the head and its appendages. This vessel is evidently the aorta.\nFig. 113 (25 to 31).\nClio Borealis*\n25.\tOne of the lingual teeth, magnified 400 diameters,\n26.\tMale generative apparatus, removed from the body and unfolded.\n27.\tFemale generative organs displayed.\n28.\tConvex surface of the testes.\n29.\tOne of the pigment sacs of the integument, magnified 120 diameters.\n30.\tNervous system, magnified 12 diameters.\n31.\tOne of the eyes, magnified 40 diameters. {After Eschricht.)\nGenerative system.\u2014 The reproductive organs in the Clio borealis occupy a very considerable portion of the abdominal cavity.\nN","page":177},{"file":"p0178.txt","language":"en","ocr_en":"178\tPTEROPODA.\nThey consist, first, of an Ovary with its oviduct; secondly of the \u201cbladder;\u201d and, thirdly, of the testis, upon which the bladder rests.\nThe ovary {fig. 113. 27, p) is closely connected with the liver,in conjunction with which it occupies the dorsal region of the abdominal cavity, its anterior part being filled with the voluminous testicle. The ovary itself is nearly of a hemispherical shape, and is of a pale red colour, its surface having a granular appearance. When crushed under the microscope, all the granules of which it consists exhibit in their interior a little vesicle, together with a dark spot ; the former being, doubtless, the vesicle of Purkinje, the latter the germinal spot of Wagner.\nThe oviduct {q) is tolerably thick, and arises from the middle of the flat surface of the ovary ; it immediately becomes considerably convoluted, so that it usually forms two loops, and, gradually becoming attenuated, reaches the \u201c bladder \u201d (\u00ab), which is situated in immediate contact with the testicle ; but, before joining the latter, it generally swells into a dilatation (/\u2019) ; but this dilatation is not constant ; for sometimes Eschricht found two such enlargements ; whilst in other instances the oviduct retained the same diameter throughout its entire length : when present, the swelling was found to be solid, and probably was produced by an accumulation of ova, coagulated by the action of the spirit in which the specimens had been preserved.\nThe \u201c bladder \u201d (s) is situated very close to the surface of the testis, and appears to be supported upon a furcate stem, through the intervention of which it is partly in communication with the oviduct, and partly with the testicle. This \u201cbladder\u201d is somewhat larger than the accidental sweliings of the oviduct alluded to above, but, like them, was found to be solid ; and sometimes the mass was divisible into two flattened halves, a circumstance that would seem to indicate the non-existence of any cavity in the interior.\nThe testis itself, in a recent specimen, is so large as to occupy a very considerable part of the abdominal cavity: it is nearly transparent ; and when portions of it are examined under the microscope, its substance seems to be entirely made up of minute tubes, connected together by delicate membranous processes. Its external convex surface {fig. 113. 28) is convoluted, so as to give it the appearance of being a hollow vesicle three times folded upon itself ; whilst its inferior concave surface exhibits under the microscope a reticulate appearance, something like that of the stomach of a ruminant quadruped.\nThe common outlet of the ovary, of the bladder, and of the testicle is short, but tolerably thick. It mounts upwards, and terminates close behind the right fin, in the immediate vicinity of the anal orifice.\nOn opening the cavity of the head, by removing its anterior wall (including the collar and the subjacent muscular layer), its contents are displayed as exhibited in fig. 111. 16. Im-\nmediately behind the contracted conical appendages, and close to their hollow bases, is seen a long milk-white organ {b), which, in old specimens, is so extremely brittle, that it is generally broken in the dissection. Behind this, and close to the collar, lies a red sac-culus not easily to be displayed ; and, in the neck itself, immediately upon the collar, is situated a single loop, formed of the same white substance as b.\nOn carefully unfolding these parts, they are found to present the structure displayed in fig. 113. 26, the transverse body {b) and the loop (c) constituting portions of the same viscus. The transverse portion is a canal terminating by a blind extremity (a), while the loop itself may be displayed as an extremely attenuated canal (d) of a reddish colour, which, after several convolutions, opens into the red sacculus (g), and ultimately terminates in another short, but wider, tube (/) ; the common orifice of the sacculus and of the convoluted canal is a wide, longitudinal opening, situated in the cavity between the right fin, the head, and the collar. On cutting into this canal, it is found that the milky colour it presents is but slightly owing to the nature of its contents, depending principally upon the texture of its walls, which, when examined under the microscope, are found to contain numerous granular bodies, which are apparently of a glandular character, united together by a very thin and transparent membrane, the delicacy of which readily accounts for the fragility of the tube.\nThe structure of the red sacculus (g) is not yet fully understood. Its walls are in some parts very thin, and on opening it, the tube (/) is seen to be continued through it.\nEschricht was, at first, in considerable doubt as to the nature of this remarkable apparatus : he observed, however, that in several specimens, a portion of the sacculus was inverted and protruded externally in the shape of a long bow-shaped organ {fig. 114. 3,h), along the cavity of which a delicate canal could be distinctly traced, the bow-shaped organ being manifestly the penis, everted in the same way as in many Gasteropod Mollusks, and the delicate canal constituting the vas deferens.\nHyalea. \u2014 The two fins are supported upon a fleshy neck, enclosed between the two lobes of the mantle {fig. 114. 3, c), which latter {fig. 114. 3, g, h, i, /c) correspond accurately with the valves of the shell, beyond the edges of which they protrude all around, and which they cover with a thin epidermis.\nThe position of the branchiae Cuvier observed not to correspond with what he had, erroneously, believed it to be in Clio,\u2014namely, the surface of the lateral fins ; for in Hyalea he could not discover any vascular net-work in those organs, even with a microscope ; and thus indirectly confirms the correctness of Eschricht\u2019s views upon this point. He, therefore, sought for them elsewhere, and, \u201c on breaking the shell, he found them to be situated between the two lobes of the mantle at the bottom of the outer space between them","page":178},{"file":"p0179.txt","language":"en","ocr_en":"PTEROPODA.\n179\non each side, so that the lateral fissures of the shell have apparently the function of admitting the surrounding element to the branchial organs. These latter are composed of little laminae, resembling those of patellae, phyllidia, &c., which surround the body so as to form a sort of elliptical belt, not placed transversely, but parallel to the course of the dorsal surface (fig. 114. 5, 6. p, q, r, s). The\nFig. 114 (1 to 9).\nAnatomy of Hyalea. (After Cuvier.')\n1.\tThe animal entire, with its shell, viewed from the side of the inflated valve.\n2.\tThe same seen from the side of the flat valve.\n3.\tThe Hyalea deprived of its shell, the lobes of the mantle drawn aside and expanded, from the inflated side.\n4.\tThe same from the flat side, in which part of the viscera maybe observed through the membrane of the mantle, as also the muscular fibre of the latter.\n5.\tThe animal slightly magnified, with the mantle opened from the flat side, showing the retractor muscle and the viscera in situ.\n6.\tThe same, with the viscera displayed.\n7. The same, seen from the opposite aspect : the integument of the neck has been divided as far as the mouth, showing the respective positions of tha brain, of the oesophagus, of the penis, and the tongue; like terminations of the retractor muscle.\n8. The penis detached.\nThe crop and gizzard laid open.\nThe same references apply to all the figures.\na, b, c, prominent points of shell ; d, inflated valve ; e, f lateral margins of the shell ; g, h, i, k, margins of mantle ; Z, m, cervical fins ; n, mouth ; o, neck ; p, q, r, s, branchiae ; t, position of the heart ; u, retractor muscle ; v, v, oesophagus ; w, crop ; x, gizzard. ; y, intestine ; z, liver ; \u00ab, ovary ; \u00df, testicle ; y, supra-\u0153sophageal ganglion.\nother viscera occupy the arched and rounded portion of the shell, or the interior of the cervical region, and are enveloped in a kind of peritoneum of a blackish colour. On placing the animal upon its flat valve, or ventral surface, the heart is seen to be situated on the right side, at the inner border of that portion of the branchial band marked t in fig. 114. 5. A cylindrical muscle (u, fig. 114. 5 and 7) is attached to the intermediate point of the shell, and traverses the visceral mass to be inserted into the neck by four tongue-like processes. The action of this muscle will be to retract the creature within its shell.\nIn front of the four branchiae is situated the penis, upon which lies the oesophagus, and this in turn is surmounted by the brain\u2014 these organs filling up the thickness of the neck. The oesophagus (v,v,fig. 114. 5 and 6) is long and slender, and the mouth, according to Cuvier, is a simple anterior opening, in the interior of which a few wrinkles only are perceptible, representing the tongue. The oesophagus dilates into a kind of membranous crop (w, w, fig. 114. 7 and 9), which is succeeded by a muscular gizzard (x,xtfig. 114. 7 and 9) of a cylindrical shape, the walls of which are of tolerable thickness. Both these cavities are furnished internally with longitudinal folds, and these are thicker and more numerous in the crop than in the gizzard (fig. 114. 9). The intestine (y,yO is slender, and of the same diameter throughout its whole length, which is considerable. It makes two convolutions in the interval between the lobes of the liver (z z,fig. 114. 7). The anus is situ-\nN 2","page":179},{"file":"p0180.txt","language":"en","ocr_en":"180\tPTEROPODA.\nated on the right side of the neck beneath the corresponding lateral fin : the liver is of no great bulk, and forms a nearly globular mass.\nThe organs of generation consist of an ovary which occupies the greater portion of the right side; of an oviduct of moderate length ; of a testicle which is almost as large as the ovary, and of a common deferent canal. The penis is here, as in Clio, an organ altogether distinct from the testicle : it is situated, as already said, beneath the oesophagus, where it is folded upon itself ; and when protruded, issues through an orifice placed in the front of the neck and a little below the mouth. It is represented in situ in fig. 114.7, and detached in 8.\nThe brain {fig. 114. 7, r) is large, flat, and of a square form, slightly narrowed posteriorly : the nerves issue principally from its angles, two of them going to join a double ganglion situated beneath the oesophagus.\nThe salivary glands appear to be wanting.\nPneu3I0dkrma. \u2014 Another genus of the Pteropod Mollusca, anatomized by Cuvier, embraces the Pneumoderma, which presents many peculiarities of structure, more especially as relates to the position of the respiratory organs and the tentacula placed at the sides of the mouth and other anatomical details, so that it will require to be described at length. In this genus, the body is without a shell, having two fins situated on the sides of the neck, but is distinguished by having two bunches of tentacula in the vicinity of the mouth, and by carrying its branchial organs at the surface of its body near its posterior extremity.\nThe body of this mollusk is of an oval shape {fig. \\ 15. 1, a), the head (5) is round,\nFig. 115. (1 to 9).\nAnatomy of Pneumoderma. {After Cuvier.')\n1.\tPneumoderma, natural size, anterior aspect.\n2.\tThe same, posterior aspect.\n3.\tThe same placed with the head downwards, and seen from the right side to show the branchiae.\n4.\tThe same enlarged and shown in the position of fig. 1. The skin is divided and turned aside to show the muscular envelope of the viscera and the pericardium in situ.\n5.\tThe same, the muscular envelope and peritoneum laid open to show the viscera in situ.\n6.\tThe same, with the viscera developed.\n7.\tThe same : the organs of generation are turned aside ; the stomach laid open and the integuments of the head divided to show the mouth and its appurtenances.\n8.\tThe mass of the mouth detached and opened longitudinally to show its interior.\n9.\tInterior of the head after the removal of the oral organs, showing the penis and the inferior ganglia in situ.\nThe same letters answer to all the figures.\na, body ; b, head ; c, mouth ; d, lips ; e, their fleshy appendage ; f fins ; g, branchi\u00e6 ; h, branchial vein ; i, auricle of heart ; k, pericardium ; 11, muscular envelope of viscera ; m, liver ; n, testicle ; o, ovary ; p, stomach laid open ; q, rectum ; r, r, fleshy appendages to oral cavity ; s, tongue ; t, u, anterior membranous compartment of mouth ; t, t, t, oral tubercles ; c, c, tentacles ; v, salivary glands ; x, their dilated ducts ; y, brain ; z, smaller mucous ganglia ; x, penis ; \u00df, opening of common generative canal.","page":180},{"file":"p0181.txt","language":"en","ocr_en":"PULSE.\n181\nand the neck constricted. The mouth opens upon the summit of the head, and is guarded in front by two longitudinal prominent lips {d, d), beneath which is a pointed, fleshy appendage (e).\nThe fins (ff), attached to the sides of the neck, are fleshy and much smaller than in either of the preceding genera.\nThe branchiae {g,g) are situated at the opposite extremity of the animal, and form two prominent lines somewhat in the shape of two capital Cs placed back to back and united by a transverse band. These lines give off from each side small prominent laminae, arranged much in the same way as the leaflets of a pinnate leaf.\nOn the right side of the body, and a little above the branchial apparatuses seen a simple prominent line {h), which, on opening the animal, is discovered to be the branchial vein opening into the auricle of the heart (i), which, enclosed in its pericardium, is situated upon this side ('k).\nOn opening the integument, which is comparatively soft, the mass of the viscera is found to be enclosed in a muscular envelope, the fibres of which are almost all longitudinal (fig. 115. 4, l, /). The pericardium is not contained within this fleshy envelope, which is only adherent to the skin in the vicinity of the branchiae ; for in this place are situated the arterial trunks, which convey the blood of the body into the pulmonary organ.\nOn dividing the muscular layer (j%. 115. 5 and 6), it is seen that almost the whole space within is nearly equally shared between the liver (m), the testicle (n), and the ovary (o), the latter being slightly the largest viseus of the three. The ovary occupies the bottom of the visceral sac, the testicle is on the left, and the liver on the right side.\nThe stomach is very capacious, and surrounded on all sides by the liver, which pours the bile directly into its interior through numerous orifices, exactly as in Conchiferous Mollusks. The walls of the stomach are thin and internally present numerous little cavities, into which the biliary pores open {fig. 115. 7, p). The rectum is short, and opens beneath the right fin {fig. 115. 7,g).\nThe mouth is a fleshy mass of considerable size, from which two fleshy appendages are prolonged backwards {fig. 115. 7,8, r r). The tongue is covered with short reverted spines, the use of which is evidently to assist in deglutition {fig. 115. 8, s). The posterior part of the mouth, in which the tongue is situated, is separated from the anterior {fig. 115,7,8,\u00ab), which is membranous, by a fleshy construction {fig. 115. 8, ttt), upon which are perceived three small tubercles.\nThe opening of the mouth is guarded by two bunches of tentacula {fig. 115. 1 to 8, c), which the animal can, at will, either protrude or retract within the oral orifice. Each of these tentacles consists of a delicate filament, terminated by a minute tubercle excavated in the centre. These organs forcibly remind us of the complicated oral apparatus of the Clio\nalready described, and most probably are instruments of prehension analogous to those of the Cephalopoda.\nThe salivary glands {fig. 115. 7, 8, v v) are long and ample, and their excretory duct, as it passes above the brain, is obviously dilated {xx).\nThe brain {fig. 115. 9, y) is a narrow transverse band, and among the nerves which it furnishes, two may be observed on each side, which are connected beneath the oesophagus with a group of six ganglia, four of which are mesial and of considerable s;ze, while the other two placed at the sides are of smaller dimensions.\nThere is nothing peculiar in the structure of the generative apparatus, which nearly resembles that of Hyalea and Clio. The penis is small, and situated beneath the mouth. It is protruded between the two little lips situated upon the anterior surface of the head {fig. 115. 1, 5, d d). The common generative orifice is found immediately in front of the anus, and is prolonged externally into a kind of furrow, which is directed forwards.\n( T. Rymer Jones.')\nTHE PULSE (Gr. fftyoynos, crcpv^is, Lat. Pulsus, Fr. Poids, Ger. Puls, Dut. Pols, Ita\u00ee. Polso, Span. Pulso). \u2014 The nature and cause of the pulse have already been examined in an earlier part of this work.* It is proposed to consider it, in this place, as a separate and independent subject, and to bring together the leading facts which have been ascertained, in reference especially to that property which is most readily submitted to examination, namely, its frequency.\nOur knowledge of this subject is little more than a century old ; for though Quetelet f attributes to Kepler, who was born towards the end of the 16th century, the idea of ascertaining the number of pulsations in a given time, Floyer, who wrote at the beginning of the 18th century, was the first who collected any considerable number of observations. Bryan Robinson J, Falconer Knox ||, Graves If, Nick **, and Quetelet j-f followed in the same field of inquiry, and still more recently the writer of this article. The facts which these authors placed on record have not yet been brought together in any standard treatise on physiology ; so that a clear and connected exposition of the frequency of the pulse, as it is affected by age, sex, posture, exercise, food, and other natural causes, and of the relation which it bears to the respiration, is still a desideratum.\n* Art. Circulation, Vol. i. p. 638.\nf Sur l\u2019Homme, vol. ii. p. 80.\nI A treatise on the Animal Economy, by Bryan Robinson, M.D., 1732.\n\u00a7 Observations respecting the Pulse, &c., by W. Falconer, M.D. F.R.S., Bath, 1796.\n|| Ed. Med. and Surg. Journal, vol. xi., 1815, and No. 131, 1837.\nDublin Hospital Reports, vol. v. 1830.\n** Beobachtungen \u00fcber die Bedingungen, unter denen die H\u00e4ufigkeit des Pulses im Gesunden Zustand ver\u00e4ndert wird. Yon Georg. Heinrich Nick.","page":181},{"file":"p0182.txt","language":"en","ocr_en":"PULSE.\n182\nIt is true that there is no want of rough estimates, or of calculations founded on theoretical data ; but there is in this, as in most kindred subjects, a great lack of careful observations, and correct average results. This deficiency it is the object of this article to supply, by presenting in succession the number of the pulse, as influenced by the principal causes already specified.\nAge. \u2014 In treating this part of the subject no distinction is made between the sexes, nor is any notice taken of the influence of posture, and time of day. The average results are based on the observations made by different authors on healthy persons of both sexes if; a state of rest, and on those of the writer ol this article, which, with the exception of \\ery young children, were taken in the sitting posture in the middle of the day, and in a state of rest and abstinence. As these latter facts form the majority of those from which the averages are calculated, it will be correct to state that the tables present a near approximation to the frequency of the pulse in persons of different ages in a state of rest and abstinence, in the sitting posture, and at or about the middle of the day.\nThe pulse has its maximum frequency in early infancy, and its minimum in robust old age. From infancy to adult age it continues to fall, and probably attains its lowest point at or about the age of 50, to rise again, if feeble as well as robust persons are included in our observations, in the aged.\nInfancy. \u2014 The frequency of the pulse is very variable at this period of life. According to Quetelet *, the numbers are as follow.\nMax. 165 ; min. 104 ; mean 135 ; range 61.\nOther authorities estimate it at 130 to 140, or at the last of these numbers ; but it will assist the memory to fix the average at 140.\nDuring the first few weeks or months of life, the frequency of the pulse in healthy children is rapidly diminished, as appears from the following Table, based on the observations of Billard, in which table the averages must be understood to be approximations.\nAge.\tMax.\tMin.\tMean.\tRange.\n1 to 10 daysf\t180\tless than 80\t106\t100\n1 to 2 months\t150\t70\t103\t80\n2 to 3 months\t100\t70\t87\t30\n* Op. cit. vol. ii. p. 86.\nf M. Yalleix (M\u00e9moires de la Soci\u00e9t\u00e9 M\u00e9dicale de Paris, vol. ii. p. 312.) gives, as the average frequency of the pulse in thirteen healthy infants from 2 to 21 days old, 87 beats, the maximum being 104, and the minimum 76. As these observations were made with singular care, they are entitled to much attention. Mr. Gorham (London Med. Gaz. vol. xxi.) obtained from sixteen observations on sixteen infants, less than one day old, a mean of 123 beats, a maximum of 160, and a minimum of 100 ; and from forty-two observations on infants, from one to seven days old \u2014128 as the average, 160 as the maximum, and 96 as the minimum. The average of three experiments on children asleep was 108. M. Trousseau (Journal des Connaissances M\u00e9dicales et Chirurgicales, Juillet, 1841) obtained, as the\nHence, then, between the first and tenth day there is a range of 100 beats ; between the first and second months, of 80 beats ; and between the second and third months, of 30 beats, with an average fall in the first three months of about 20 beats. The numbers of observations on which these averages are founded are, between 1 and 10 days, 56 observations ; between 1 and 2 months, 36 observations ; and between 2 and 3 months, 20 observations.* It would answer no good purpose to enter more minutely into the frequency of the pulse at these early periods of life i it will suffice to present it year by year during the first twenty-five years of life, as is done in the following table, based upon between 600 and 700 observations made chiefly by the writer of this article, each average being deduced either from 20 or 25 facts.\nAge.\tMax.\tMin.\tMean.\tRange.\n1\t158\t108\t128\t50\n2\t136\t84\t107\t52\n3\t124\t84\t106\t40\n4\t124\t80\t105\t44\n5\t133\t80\t101\t53\n6\t124\t70\t95\t54\n7\t128\t72\t90\t56\n8\t112\t72\t92\t40\n9\t114\t65\t87\t49\n10\t120\t76\t91\t44\n11\t100\t56\t84\t44\n12\t120\t70\t94\t50\n13\t112\t70\t84\t42\n14\t114\t68\t86\t46\n15\t112\t60\t84\t52\n16\t104\t66\t83\t38\n17\t102\t54\t76\t48\n18\t104\t58\t74\t46\n19\t108\t60\t76\t48\n20\t106\t52\t72\t54\n21\t99\t59\t74\t40\n22\t96\t41\t68\t55\n23\t100\t60\t74\t40\n24\t84\t52\t71\t32\n25\t88\t59\t73\t29\naverage and extreme numbers of the pulse in six boys and five girls, aged from fifteen to thirty days, the following: \u2014 boys, max. 152, min. 96, average 127 ; girls, max. 152, min. 120, mean 135.\n* It is necessary to observe, that the observations of Billard, which give so low a frequency as 70 and 80 beats as of not infrequent occurrence before the third month, and even in the first ten days of life, are by no means borne .out by the observations of the writer, or of any author whom he has consulted, with the exception of M. Yalleix. Thus, the minimum during the first day is 104 ; nor does the pulse fall in any instance lower than that number till the eighth week, when the least number is 90. If, again, the facts are grouped by months, the pulse is found in no case to fall below 104, except in one instance in the second month, till the eighth month, when the minimum is 96. The minimum observed by M. Yalleix, occurred in a male infant, a year old, admitted into the infirmary of the H\u00f4pital des Enfants Trouv\u00e9s, in a state of languor, but free from disease. In a week from the date of admission the pulse had risen to 108 ; on the following day it was 117 ; and the day after that it was 113. There is reason to believe, therefore, that these low frequencies of the pulse of infants occur in that state and degree of debility without disease which gives rise to an infrequent pulse in the adult, and that they do not occur in strong and vigorous health.","page":182},{"file":"p0183.txt","language":"en","ocr_en":"PULSE.\n183\nThis table, though obviously based upon a number of facts too small to furnish exact averages, may be taken as presenting an approximation to the truth. It indicates a progressive decline from infancy to adult age as the true law of the pulse, \u2014 a law which would probably be clearly displayed by averages deduced from a large number of facts.\nThe following table presents the number of the Pulse at each quinquennial period throughout the whole of life. The averages for the first eight periods are founded each on 50 observations, of which half were made on males, and half on females. The average for the period from 76 to 80 is deduced from the same number of facts similarly divided. For most of the other periods the averages are derived from forty observations, twenty on males, and twenty on females. Where the number of observations is less than this, it is stated in a note.\nAge.\t\tMax.\tMin.\tMean.\tRange.\n2 to\t5\t128\t80\t105\t48\n5 \u2014\t10\t124\t72\t93\t52\n10 \u2014\t15\t120\t68\t88\t52\n15 \u2014\t20\t108\t56\t77\t52\n20 \u2014\t25\t124\t56\t78\t68\n25 \u2014\t30\t100\t53\t74\t47\n30 \u2014\t35\t94\t58\t73\t36\n35 \u2014\t40\t100\t56\t73\t44\n40 \u2014\t45\t104\t50\t75\t54\n45 \u2014\t50\t100\t49\t71\t51\n50 \u2014\t55*\t88\t55\t74\t33\n55 \u2014\t60\t108\t48\t74\t60\n60 \u2014\t65\t100\t54\t72\t46\n65 \u2014\t70\t96\t52\t75\t44\n70 \u2014\t75\t104\t54\t74\t50\n75 \u2014\t80\t94\t50\t72\t44\n80 and j up wardsf J\t\t98\t63\t79\t35\nThe want of regularity in this table arises from the same cause as in the former \u2014 the comparatively small number of facts. A regular and progressive decrease in the mean values, however, would probably not be obtained by any number of observations which it is in the power of a single individual to bring together, whether as the result of his own inquiries, or as derived from the recorded researches of others. But the figures of this table will still suffice to indicate a law of progressive decrease from the beginning to the end of life, with an increase during the period of decrepitude. The decrease during the first four quinquennial periods is very rapid ; during the fourth and fifth the number remains nearly stationary ; from the fifth to the sixth period there is again a fall of a few beats ; but during the remainder of life (from 25 to 80) a very slight difference exists between the several quinquennial periods ; the difference between the averages amounting to only 4 beats, between the minima to 10 beats, and between the maxima to 20 beats. The average rise during the period of decrepitude amounts to 7 beats. J\n* 22 Observations.\tt 29 Observations.\nI It would be interesting to accumulate observ-\nThe pulse of the aged has been very carefully examined by Leuret and Mitivi\u00e9* *, Hourmann and Deschambre-j-, and Dr. C. W. Pennock.j According to the observations of the first-named authorities, the average frequency of the pulse in 27 males and 34 females, each sex being of the mean age of 71 years, was, in round numbers, 76. The number would have been somewhat higher but for the exclusion, as abnormal, of pulses exceeding 100. Dr. Pennock\u2019s observations on 170 males and 203 females, of the mean age of about 67 years, give as the average frequency of the pulse, 75 beats. The observations of Drs. Hourmann and Deschambre having been made solely on females, are not available in this place. It will be seen that the results deduced from the observations of Leuret and Mitivi\u00e9, and of Dr. Pennock do not differ materially from the numbers in the table.\nAs it is extremely difficult, even for those who are most in the habit of dealing with figures, to remember the exact results of a series of averages, it may be useful to lay down a near approximation to the average numbers at the several leading periods of life. This is done in the following table.\nAt birth\t-\t_\t- 140\nInfancy\t-\t-\t- 120\nChildhood -\t-\t-\t- 100\nYouth -\t-\t-\t-\t90\nAdult age\t-\t-\t-\t75\nOld age\t-\t-\t-\t70\nDecrepitude -\t-\t-\t-\t75\u201480.\nSex. \u2014 The recorded observations on the pulses of males and females respectively during the early periods of life are few in number. At birth, according to the observations of Quetelet, there is a difference of only one beat, the average number in males being 136, and in females 135. The following table contrasts the two sexes at those periods at which the number of recorded observations, added to those made by the writer of this article, are\nations on the pulse of the same person at different periods of life. The following memorandum, by the writer, of two series of observations on his own pulse, may be worth preserving. From an average of nine experiments made during my twentieth year, in the evening, between the hours of 9J and 11\u00a3, p.m., in the sitting posture, and, after remaining some time quiet (in one experiment some hours, and in two others during four hours each), the pulse was 72 per minute. From an average of the first nine experiments which present themselves, made under as nearly as possible the same circumstances, in my twenty-seventh year, the pulse is 55 per minute. Thus, in the space of seven years, it may be fairly inferred that the average frequency of my pulse has fallen from 72 beats per minute to 55, being a difference of 17 beats.\n* De la Frequence des Pouls, chez les Ali\u00e9n\u00e9s, par MM. Leuret et Mitivi\u00e9, p. 35.\n\u25a0j- Archives G\u00e9n\u00e9rales de M\u00e9dicine (2nd series), Nov. 1835, tom. ix. p. 338.\nJ Note on the Frequency of the Pulse and Respiration of the Aged. By C. W. Pennock, M. D., American Journal of Medical Science, July 1847.\nN 4","page":183},{"file":"p0184.txt","language":"en","ocr_en":"184\nPULSE.\nsufficiently numerous to furnish a fair average.*\n\tMales.\tFemales.\nUnder 2 years\t110\t114\n2 \u2014\t5 \u2014\t101\t103\n5 \u2014\t8 \u2014\t85\t93\n8 \u2014 12 \u2014\t79\t92\nIt would appear, then, that even at a very early period of life, the difference of the sexes is marked in the pulse j- ; that this difference is very inconsiderable in infancy, but well marked in childhood.\nThe following table presents, in septennial periods, the results of the observations of the writer during the whole of life. Each average is founded on 25 observations, made with great care, in apparently healthy persons, fasting, in a state of rest, in the middle of the day, and in a sitting posture.\nMALES.\t\t\t\t\nAge.\tMax.\tMin.\tMean.\tRange.\n2 to 7 years\t128\t72\t97\t56\n8\u201414\t108\t70\t84\t38\n14\u201421\t108\t60\t76\t48\n21\u201428\t100\t53\t73\t47\n28\u201435\t92\t56\t70\t36\n35\u201442\t90\t48\t68\t42\n42\u201449\t96\t50\t70\t46\n49\u201456\t92\t46\t67\t46\n56\u201463\t84\t56\t'68\t28\n63\u201470\t96\t54\t70\t42\n70\u201477\t94\t54\t67\t40\n77\u201484J\t97\t50\t71\t47\n\tFEMALES.\t\t\t\n2\u2014 7\t128\t70\t98\t58\n8\u201414\t120\t.70\t94\t50\n14\u201421\t124\t56\t82\t68\n21\u201428\t114\t54\t80\t\u00ab0\n28\u201435\t94\t62\t78\t32\n35\u201442\t100\t56\t78\t44\n42\u201449\t106\t64\t77\t42\n49\u201456\t.96\t64\t76\t32\n56\u201463\t108\t60\t77\t48\n63\u201470\t100\t52\t78\t48\n70\u201477\t104\t54\t81\t50\nGO cCo\t105\t64\t82\t41\nThe same remarks apply to this table as to former tables. The number of facts is not large enough to give a steady and progressive decrease from childhood to age ; but that the approximation to a true result is sufficiently close for all practical purposes may be in-\n* The averages are deduced from the following numbers of facts. Under 2 years, 28 and 21 facts ; 2 to 5 years, 27 and 23 facts ; 5 to 8 years, 32 and 33 facts ; 8 to 12 years, 46 and 59 facts.\nf This is in accordance with the observations of M. Valleix. (Op. cit.)\nJ An average of 18 observations on males between 80 and 90 by Dr. Pennock gives 72\u00a3 beats.\n\u00a7 Observations by Dr. Pennock on 37 females between 80 and 90 give an average of 75 only ; and observations on 7 females between 90 and 115, 76\u00a3.\nferred from the following comparison of the extreme and mean results derived from 25 and 50 observations respectively on the pulses of healthy males.\nNo. of Observations.\t\tAge.\tMax.\tMin.\tMean.\tRange.\n251\t\t2 to 7\t( 128\t72\t97\t56\n50 J\t\t\t(128\t72\t97\t56\n25]\t\t7\u201414\tf 108\t70\t84\t38\n50 J\t\t\t1108\t68\t85\t40\n251 50 J\ti\t14\u201421\tf 108 (108\t60 60\t76 78\t48 48\nA similar comparison in the female issues in the same manner, as will be seen by the following table.\nNo. of\t\t\t\t\t\t\t\nObserv-\t\tAge.\tMax.\t\tMin.\tMean.\tRange.\nations.\t\t\t\t\t\t\t\n251\tL\t7 to 14\tJ\tf 120\t70\t94\t50\n50 J\tr\t\t\t[ 120\t70\t95\t50\n251 45 J\t\u00bb\t14\u201421\ti\tri24 [124\t56 56\t82 80\t68 68\n251\t!\t71\u201477\tJ\tf 104\t54\t81\t50\n45 J\tr\t\t\t[104\t54\t80\t50\nIt will be seen that in neither comparisoi does the difference between the averages fo the larger and smaller number of observation exceed two beats, while the extremes, with one exception (the minima in the male, from 7 to 14), are the same. The sufficiency o the averages for practical purposes may also be fairly inferred from the result of a simple process of elimination adopted in the case of the female pulse. By taking 26 observations, and excluding the three maxima and the three minima, as being possibly due to a departure from perfect health, an average of 20 observations was obtained, which gave the following regular series of numbers for the twelve septennial periods of the table \u2014 98, 94, 81, 80, 79, 78, 75, 75, 77, 78, 81, 82, showing a steady and progressive decrease during the first eight periods, and an equally progressive increase during the last four periods.\nThe difference between the male and female pulse continues to be well marked in advanced ages. Thus, in the observations of Leuret and Mitivi\u00e9, the average frequency in 27 aged men was 73, and in 34 aged women 79. The average obtained by Drs. Hourmann and Des-chambre, by observations on 255 aged females was 82. Dr. Pennock\u2019s averages are 72 foraged males, and 78 for aged females.\nThe general results deducible from the foregoing tables, in reference to the influence of sex on the pulse, may be tfius expressed :___\n1. The female pulse differs little from the male pulse during the first seven years of life ; but after seven years of age the mean pulse of the female exceeds that of the male by from 6 to 14 beats ; the average excess being 9 beats,","page":184},{"file":"p0185.txt","language":"en","ocr_en":"PULSE.\t185\nor about one-eighth of the mean frequency in the male.\n2.\tThe minimum frequency of the pulse of the female, at more than one period of life, falls below that of the male ; but its maximum frequency is, at all periods, above that of the male.\n3.\tThe range of the pulse in both sexes is considerable ; in the male it extends from 28 to 56, in the female from 32 to 68 beats, and it is probable that more numerous observations would extend this range still farther. The average range in the male is 43 ; in the female, 48.\n4.\tFor the purpose of assisting the memory, the average pulse of the adult male may be stated at 70, that of the adult female at 80. The highest number is somewhat less than 100 in the adult male, and somewhat more than 110 in the adult female. The least number in each is about 50.\nThe lowest number recorded in the table, as occurring in healthy males, is 46, and in healthy females 52. These, however, are not the least numbers on record ; for Heberden counted 42, 30, and even 26 pulses in healthy males, the latter number in a man of 80 ; and Fordyce one case of 26, in an old man in the Charter-house, and another of 20. The writer, some years since, met with a pulse of 38 in a gentleman then and now in the enjoyment of good, though not robust, health. The lowest number observed by Floyer was 55. Falconer counted a pulse of 36, and another of 24, in healthy females, and Dr. Graves records one of 38. Pulses as low as 16, or even 14 beats, have been counted ; but it is doubtful whether the persons in whom they occurred were healthy. Low frequencies of pulse observed in disease are beyond the scope of this essay. On the other hand, it is probable that extended observations would reveal the occasional occurrence in healthy persons of both sexes of higher frequencies of the pulse than any recorded in the tables.\nTemperament. \u2014 Nothing is at present known of the frequency of the pulse as influenced by temperament. The speculations of Floyer upon this subject are too fanciful, and have too little foundation in fact, to deserve a place among the sober results of observation.* The writer\u2019s experience would lead him to attach little importance to temperament as a cause of variation in the pulse, as he has found high and low frequencies in men of the same temperament ; and some of the lowest pulses he has observed have been in males of opposite temperaments. It is not uncommon, too, to find pulses of very low frequency in persons of the sanguine temperament, and in men remarkable for energy of character and nervous excitability. The strumous diathesis is often characterised by a feeble pulse of low frequency, while those who are subject to gout have, as a general\n* The choleric tempers may be betwixt these numbers 75 and 80, the salt betwixt 80 and 85, the phlegmatic betwixt 70 and 65, the cold melancholy betwixt 65 and 60\u2014 Pulse Watch, p. 57.\nrule, a stronger pulse of higher frequency. It is probable that, c\u00e6tens paribus, the large chest and muscular frame are accompanied by an infrequent, and the small chest and spare form by a frequent pulse. But the varying frequencies of the pulse observed in different subjects have yet to be submitted to that extended and searching observation by which alone the several concurrent causes can be successively eliminated, and the most influential circumstances displayed.\nStature. \u2014 Bryan Robinson * has some speculations and calculations upon this cause, which deserve to be classed with the fanciful conceits of Floyer. They profess to be strictly founded upon observation ; but their fallacy will be apparent, when it is stated that the important element of age is altogether overlooked. Falconerf follows the example of Bryan Robinson ; and more recently M.Rameaux J, in a letter addressed to M. Quetelet, pursues the same unprofitable inquiry. The observations, 64 in number, were made by M. Pingrenon, an army surgeon. The subjects examined were all healthy soldiers, placed in similar circumstances, which circumstances, however, are not specified, nor are the ages mentioned. The ordinary range of age in soldiers of the same regiment is quite sufficient to account for the very slight differences of frequency which M. Rameaux attributes to stature. How slight that difference is will be seen from the following comparison :\u2014Stature, 5 feet 6\u00a7 inches ; pulse, from observation, 64-43 : stature, 5 feet 9 inches ; pulse, also from observation, 62\u201862. The calculated numbers are 64\u201906 and 63. $ The effect of stature on the pulse has yet to be determined, and it will require a large assortment of observations made on persons of the same sex and age, at the same time of the day, in the same posture of the body, and placed in all respects under the same circumstances.\nPosture. \u2014 No part of the subject of the pulse, not even excepting its diurnal variations, has been more carefully examined than the influence of the posture of the body. Though the broad fact, that the pulse in disease is affected by change of posture, seems to have been familiar to the ancients, the first recorded experiment on the healthy subject was made by Bryan Robinson [|, who obtained the following numbers : \u2014 Standing, 78 ; sitting, 68 ; lying, 64. Dr. Macdonnell is the next person who devoted his attention to this subject, and who appears, from his own statement, to have been engaged upon it so early as the year I784.t Falconer, in his work\n* Animal Economy, p. 182\u2014134.\nf P. 10\u201413.\nj Bulletins of the Koyal Academy of Brussels, vol. vi.\n\u00a7 The little importance to be attached to these results will appear, when it is stated that by disregarding the influence of sex, and looking only to the stature of the body, the pulse of the female is made to exceed that of the male by only two or three beats, instead of the true number 9 or 10 beats.\nOp. cit. p. 177.\nTransactions of the British Association for the","page":185},{"file":"p0186.txt","language":"en","ocr_en":"186\nPULSE.\npublished 1796, investigated the subject more carefully, and states, that \u201c the result of twenty-one accurate trials, made on different days and at different times of the day, all coincided to prove the greater frequency of the pulse standing, than sitting or lying.\u201d The greatest difference observed was 13 beats in a minute, and the least difference one beat. Each of these, however, occurred once only. The average difference between the above postures was about six and a third in a minute.\u201d He adds, \u201c The pulse in health is, as far as I can find, the same in a sitting as in a horizontal posture.\u201d Dr. Knox of Edinburgh* * * * \u00a7, however, has examined the effect of posture on the pulse still more closely than the authors just mentioned. In his first memoir, published in 1815, he says, \u201c During the morning, the mere change of posture, from the horizontal to the erect, shall increase the pulse by about 15 or 20 beats. At midday this increase shall be 10 ; and in the evening 4, or 6.\u201d In his second essay, published in 1837, Dr. Knox gives the results of actual experiment. Nickf, in 1826, and Dr. Graves J, in 1830, also examined the subject experimentally. It is unnecessary to pursue the history of this department of the pulse into greater detail, as the fact that the pulse is greatly influenced by posture is now familiar to all medical men. The exact amount of the change due to this cause will, perhaps, be best displayed in the average i*esults obtained by the writer from a large number of facts observed by himself. $\nThe following averages were derived from observations on 100 healthy males of the mean age of 27 years, in a state of rest, unexcited either by food or exercise, and, for the most part, between the hours of 12 and 2 p. m. : \u2014\nStanding, 18*90 ; sitting, 70\u201805 ; lying, 66*62. j|\nDifference between standing and sitting, 8*85 ; between sitting and lying, 3*43 ; and between standing and lying, 12*28.\nThese are the average results, from which, however, the extremes are very widely separated ; for the difference between standing and sitting ranges from 26 to 0 ; that between sitting and lying, from 18 to 0 ; and that between standing and lying, from 44 to 0. The numbers in the observation, at the highest extreme of the scale, were as follows : \u2014\nAge, 20. Standing, 98 ; sitting, 72 ; lying, 51 : differences, 26, 18, and 44.\nTo the general rule that the pulse is more frequent standing than sitting, sitting than\nAdvancement of Science, Dublin Meeting, 1835, p. 97.\n* Ed. Med. and Surg. Journal, vol. xi. and No.\n131.\nf Op. cit. p. 41.\nJ Op. cit. p. 561.\n\u00a7 Guy\u2019s Hospital Reports, Nos. vi. and vii.\n|| It is a remarkable coincidence that Dr. Harden, as the average of several experiments on his own person, obtained the same numbers, viz. 80, 70, and 66. See American Journal of Med. Science, vol. v. p. 342.\nlying, and, \u00e0 fortiori, standing than lying, there are several exceptions. Thus there were 5 instances in which there was no difference between standing and sitting ; 19 in which there was no difference between sitting and lying ; and 2 in which the pulse had the same frequency standing and lying. Again, the pulse was more frequent sitting than standing in 3 instances ; lying than sitting in 11 instances ; lying than standing in 5 instances. The total number of instances, in which exceptions to the general rule occurred, was 34, or one-third of the whole.\nIf we exclude all exceptions to the general rule, and deduce an average from the 66 observations in which the pulse had what may be termed its normal character, we obtain the following numbers : \u2014\nMean age, 27; standing, 81*03; sitting, 71*12; lying, 65*62: differences, 9*91,5*50, and 15*41.\nThe female pulse presents some peculiarities worthy of note, as will appear from the following average results of 50 observations made under the same conditions as those just recorded : \u2014\nMean age, 27. Standing, 89*26 ; sitting, 81*98 ; lying, 80*24 : differences, 7*28, 1*74, and 9*02.\nThe extreme results, in the female as in the male, are very wide of the averages ; for the difference between standing and sitting ranged from 24 to 0 ; between sitting and lying, from 11 to 0 ; and between standing and lying, from 28 to 0. The exceptions to the general rule are still more numerous in the female than in the male, the total number of exceptions being 60 per cent., and the number of observations in which exceptions occurred 46 per cent. Of course the rule here referred to is the general rule established by observations on the male pulse.\nIf, then, we compare the effect of change of posture on the male and female pulse, we discover that the effect is greater, and the exceptions to the rule less numerous, in the male than in the female. This part of the subject will repay a somewhat close examination.\nIn the following table, the numbers of the pulse, and the differences due to change of posttfTe, are given, in round numbers, the averages being deduced from 66 observations in the male, and 27 in the female, from which all exceptions to the rule are excluded. The mean age in both sexes is 27.\nMales Females\tStanding.\tSitting.\tLying.\tDifferences.\n\t81 91\t71 84\t66 80\t10 5 15 7 4 11\nFrom this table it appears, that though the female pulse exceeds the male by 10 beats, or \u00a3th, the effect of a change of posture is considerably less in the former than in the latter. But, in order to determine the true relation","page":186},{"file":"p0187.txt","language":"en","ocr_en":"PULSE.\n187\nexisting between the pulses of the two sexes in this respect, it is necessary to compare equal things with equal. This is done in the following table, where the pulse in the erect posture, as deduced from 101 observations on males of the average age of 27 years, and 74 observations on females of the average age of 25^ years, is in either sex 86.\nMale | Female j\tStanding.\tSitting.\tLying.\tDifferences.\n\t86\tl>- i-H U- GO\t72 80\t9 5 14 5 16\nSo that for the same frequency of pulse the effect of change of posture in the male is more than twice as great as in the female. The difference is still more strongly marked in earty youth.\nThe instances in which one or more exceptions to general rules occurred are, as already stated, more numerous in the female than in the male, the exact proportions being 46 per cent, and 34 per cent. The next question connected with the effect of change of posture on the pulse is, whether that effect is the same at all ages ? The following table answers this question for both sexes in the negative. The averages are deduced from 30 observations at each age in the male, and 20 in the female.\n\tStanding.\tSitting.\tLying.\tDifferences.\nMALE.\t\t\t\t\nUnder 20, mean age 15 \\ Above 20, mean age 29 j\t83\t(76 173\t73 69\t7 3 10 10 4 14\nFEMALE.\t\t\t\t\nUnder 20, mean age 111 Above 20, mean age 38 j\t92\tco co to 00\t88 81\t4 0 4 10 1 11\nHence, in the male, the difference above 20 between standing and lying is to the difference below 20 as 7 to 5 ; while, in the female, the difference above 20 is to that below 20 as nearly 3 to 1. The exceptions to the general rule are also more frequent in the young subject.\nAnother question connected with the effect of posture on the pulse requires to be examined, namely, does that effect vary with the frequency of the pulse ? The following tables will be found to furnish an answer in the affirmative. The averages in the first table are founded each on 15, and in the second table on 10, observations.\nIt will be seen that these tables concur in establishing the general rule, that the effect of change of posture increases with the frequency of the pulse; in the male as the numbers 9,15, 27, 39; in the female as the numbers 8, 12,18.\n\t50 to 70\t\t\t70 to 90\t\t\n\tStanding.\tSitting.\tLying.\tStanding.\tSitting.\tLying.\n\t61\t55\t52\t81\t68\t66\nDifferences.\t6\t3\t9\t13\t2\t15\n\t90 to 110\t\t\t110 to 130\t\t\n\tStanding.\tSitting.\tLying.\tStanding.\tSitting.\tLying.\n\t101\t82\t74\t120\t93\t81\nDifferences.\t19\t8\t27\t27\t12\t39\n\t\nFEMALES.\t\nDifferences.\n60 to 80\t\t\t80 to 100\t\t\nti\t\t\tbb\t\t\n.5 \u00bb3 1\tbn s 3\tbn a\t\u2022S \u00a3 cS\t.a \"\u25a0+3\tti a\nXfl\ti\u00df\ti-l\tw.\ti\u00df\ti-3\n71\t67\t63\t92\t85\t80\n4\t4\t8\t7\t5\t12\nDifferences.\n100 to 120\n108\n11\n97\nAnother fact bearing on the effect of posture on the pulse, is established by the observations of the writer, in confirmation of less accurate experiments previously made by Dr. Knox and others, viz. that that effect is not the same at all periods of the day. The only satisfactory way of ascertaining this fact is by contrasting the same frequency of the pulse at different periods of the day. This was done by the writer, who employed an average of twenty observations on his own pulse, made before noon, twenty between 12 and 5\u00a7 P.M., and twenty between 5\u00a3 r. m. and midnight. The greatest average difference between standing and lying (10 beats) occurred before noon, the number in the afternoon being 8, and in the evening 9.\nThe cause of the different frequency of the pulse in different postures of the body is a question of some interest, in examining which","page":187},{"file":"p0188.txt","language":"en","ocr_en":"PULSE.\n18\u00f6\nit is necessary to premise that the increase or diminution of frequency attending the change from one posture to another, is not merely a transient effect, dependent upon the muscular effort involved in the act of change, but a permanent state, continuing as long as the respective postures are maintained. This was long since stated by Dr. Graves * * * \u00a7, who proved experimentally that when the posture of the body was changed without any effort of its own muscles, \u201c the difference between the frequency in the horizontal and erect postures was not less than when muscular exertion was used.\u201d The mode in which Dr. Graves effected this change of posture is not stated ; but in experiments performed by the writer of the present article, by means of a revolving board f, a difference amounting to less than a single beat was found to exist between the average of twenty experiments, in which the body was transferred from one posture to the other by the machine, and an average of twenty experiments, in which the change of posture was effected by the voluntary efforts of the same persons. The round numbers with the machine were,\u2014standing 87, lying 74, difference 13; without the machine,\u2014 standing 89, lying 77, difference 12. This very slight difference is due to the effort of the muscles in effecting the change of position. When this is subtracted there still remains a much more considerable difference attributable to some permanent cause, which may be either the continuance of muscular effort, or some other condition. The difference of opinion which has existed upon this subject, gives an interest to the following brief summary of the explanations advanced by the leading writers on the pulse.\nBryan Robinson j, Falconer \u00a7, and Knox, without attempting to submit the question to the test of experiment, attribute, directly or by inference, the different frequency of the pulse, in different postures, to muscular contraction. Dr. Graves ||, however, confesses himself to be altogether at a loss for an explanation ; Dr. Arnott seems to refer it to the more or less favourable position of the body, in respect to gravity, while other authors attribute it to the varying positions of the heart and its valves.** Very little consideration is required to show the futility of all the other causes, except that assumed by Robinson, Falconer, and Knox. The two postures between which there is the most marked difference in the frequency of the pulse, viz. the erect and sitting postures, are precisely those in which there is no difference in the position of the heart or its valves, and very little difference in the resistance offered to the circulation ; while the\n* Op. cit. p. 562.\nf Guy\u2019s Hospital Reports, No. VI.\n+ Op. cit. p. 177.\n\u00a7 Op. cit. p. 34.\n[ || Op. cit. p. 570.\n\u2022t Elements of Physics, vol. i. p. 570.\n** See an Essay by Mr. Blackley, \u201c On the Cause of the Pulse being affected by the Position of the Body,\u201d in the Dublin Journal of Medical and Chemical Science, July, 1834.\nsitting and recumbent postures, between which there is so slight a difference in the number of the pulse, are accompanied by a marked change in the position of the heart and its valves, and of the column of blood to be propelled. On the other hand, the difference in the amount of muscular contraction required to support the body in the erect and sitting postures, is much more considerable than that required to support the body in the sitting and recumbent positions\u2014differences in strict conformity with the observed frequencies of the pulse in the several postures. This simple process of reasoning, therefore, serves to show the fallacy of the explanations now alluded to, and the reasonableness of the remaining alternative\u2014 muscular contraction.\nWith this strong probability the authorities just cited seem to have been satisfied; and as it did not occur to them to submit this very reasonable theory to the test of actual experiment, it was reserved for the writer of this article to place this mooted question beyond the reach of doubt.\nThe experiments required for this purpose were of the very simplest kind. It was merely necessary in successive experiments to place the body in such circumstances as to exclude every other assigned cause but the contraction of the muscles ; in other words, the position of the body, and consequently of the organs of the circulation, remaining the same, first to support the body, and then to call its own muscles into action to maintain its position.\nThe following are the results of a series of such experiments.\n1.\tDifference between the pulse in the erect posture, without support, and leaning in the same posture, on an average of twelve experiments on the writer, 12 beats; and on an average of eight experiments on other healthy males, 8 beats.\n2.\tDifference in the frequency of the pulse in the recumbent posture, fully supported, and partially supported, 14 beats, on an average of five experiments.\n3.\tSitting posture (mean of ten experiments on the writer), back supported, 80 ; unsupported, 87 ; difference, 7 beats.\n4.\tSitting posture with the legs raised at right angles to the body (average of twenty experiments on the writer), back unsupported, 86; supported, 68 ; difference, 18 beats. An average of fifteen experiments of the same kind on other healthy males gave the following numbers : \u2014 back unsupported, 80; supported, 68; being a difference of 12 beats.\nThese experiments, with the simple reasonings already advanced, serve to demonstrate the true cause of the varying frequency of the pulse in different postures of the body to be muscular contraction.\nThe effect of an inverted position of the body on the frequency of the pulse has been made the subject of experiment by Dr. Graves, and subsequently by the writer of this essay. The reader is referred for an exact account of the experiments to the Guy\u2019s Hospital","page":188},{"file":"p0189.txt","language":"en","ocr_en":"PULSE.\t189\nReports, No. VIT. It will be sufficient to state, that in the inverted position of the body the pulse becomes less frequent, especially in persons accustomed to this unusual posture. In two such instances the difference between the erect and recumbent postures equalled that between the recumbent and the inverted postures, being in both cases 15 beats.\nThe following is a short summary of the leading facts relating to the effect of posture on the pulse.\n1.\tIn the healthy adult male the mean numbers of the pulse are as follows:\u2014 Standing, 79; sitting, 70; lying, 67; including all exceptions to the rule. Standing, 81 ; sitting, 71 ; lying, 66 ; excluding all exceptions to the rule.\n2.\tIn the healthy adult female the numbers are:\u2014Standing, 89; sitting, 82; lying, 80; including all exceptions to the rule. Standing, 91 ; sitting, 84 ; lying, 80; excluding all exceptions to the rule.\n3.\tIn both sexes the extremes are very remote from the mean results, and the exceptions to general rules very numerous.\n4.\tIn both sexes, also, the effect of change of posture increases as the frequency of the pulse increases; but the exceptions to general rules are more numerous as the pulse is less frequent.\n5.\tThe effect of change of posture on any given frequency of the pulse is much greater in the male than in the female.\n6.\tThe effect of change of posture on the pulse is less in early youth than in the adult, and the modifying influence of age is greater in the female than in the male.\n7.\tThe exceptions to general rules are more numerous in early youth than at the adult age.\n8.\tThe exceptions to general rules are more numerous as the effect of change of posture is less.\n9.\tThe effect of change of posture on the pulse is greater in the forenoon than in the afterpart of the day.\n10.\tThe inverted posture of the body lessens the frequency of the pulse.\n11.\tThe varying frequency of the pulse in different postures of the body is due to muscular contraction.\nExercise.\u2014 Muscular exertion increases the frequency of the pulse more than any other cause, as will sufficiently appear by the following quotation from Bryan Robinson.* \u201c The pulse, in a minute, of a man lying, sitting, standing, or walking at the rate of two miles in an hour, at the rate of four miles in an hour, or running as fast as he could, were 64, 68, 78, 100, ^140, and 150 or more.\u201d Change of posture, as has just been proved, forms merely a particular case of muscular effort. The act of changing from one posture to another, and the maintenance of different positions by the action of the muscles, both occasion an increased frequency of the pulse ; so also does the stretching out of the arm or the holding of it in the same posture, the\n* Op. cit. p. 177.\npulse rising rapidly with the continuance of the effort, and falling, as the writer has proved experimentally, on returning to a state of rest, below the frequency which it had before the effort was made ; and the same observation applies to fatigue induced by long continued exertion, as in walking. The cause of the increased frequency of the pulse which attends muscular effort is partly mechanical, that is to say, depending on the rapid propulsion of the blood through the large veins, and partly due to the effort of the will which sets the muscles in action. It is probable, however, that the first-named cause is by far the most influential.\nPassive exercise, as in riding and the various forms of carriage conveyance, has also a marked effect on the pulse ; an effect partly due to the varying action of the muscles in supporting the different postures into which the body is being constantly thrown, and partly to a cause correctly pointed out by Dr. Ar-nott in the following passage.\n\u201c In a long vein below the heart, when the body falls, the blood, by its inertia and the supporting action of the vessels, does not fall so fast, and therefore really rises in the vein ; and as there are valves in the veins preventing return, the circulation is thus quickened without any muscular exhaustion on the part of the individual. This helps to explain the effect of the movement of carriages, of vessels at sea, of swings, &c., and the effect on the circulation of passive exercise generally, and leaves it less a mystery why these means are often so useful in certain states of weak health.\u201d*\nTime of Day\u2014Diurnal Variations of the Pulse. \u2014 This subject demands a more minute examination than it has yet received ; for it is extremely interesting in a physiological point of view. All the older and several comparatively modern authorities agree in representing the pulse as more frequent in the evening than in the morning. Haller f, Rye and Schwenke |, Gregory$, Zimmerman ||, Hufeland 1\u201c, Quetelet**, Fod\u00e9r\u00e9ff, Falconer ft, Double, and Cullen, and, among modern physiologists, Dr. Bostock $$, describe an increase of frequency towards evening; and more than one of these authors speak of a similar change occurring at noon and in the afternoon. Cullen especially insisted on this latter circumstance.\nIt will facilitate our inquiry if we confine our attention for the present to the frequency of the pulse in the morning and in the evening, or in the earlier and later periods of the day, reserving the alleged increase of frequency\n* Elements of Physics, vol. i. p. 52.\nj- Opera Physiologica, Sectio 2, \u00a7 xvii.\nt Quoted by Haller, as above.\n\u00a7 Conspectus Medicin\u00e6 Theoretic\u00e6, cap. xv. ccccliii.\n|| On Experience in Physic, vol. i. p. 250.\nMakrobiotik, p. 53.\n** Essai sur l\u2019Homme Moyen, tom. ii, p 88.\nff Essai de Physiologie Positive, torn. i. o. 190.\ntf Op. cit. p. 24.\n\u00a7\u00a7 Cyclop\u00e6dia of Practical Medicine, art. Pulse.","page":189},{"file":"p0190.txt","language":"en","ocr_en":"190\nPULSE.\nat noon and in the afternoon for subsequent consideration.\nThe earlier authorities who have been cited as favourable to an increase of frequency towards evening were not without support from actual experiments, though those experiments were made in ignorance or disregard of some essential circumstances which tended to impair their value, such as the effect of posture and of food and exercise.\nThe earliest series of experiments which admits of being employed for the purpose of deciding this question is that contained in the Medicina Statica Britannica of Keill, published in 1718, and which the writer has been at some pains to analyse. Next in order of time are the tables of Bryan Robinson, published in his Animal Economy, 1732. The last series of facts, in confirmation of the opinion of the older authorities, was published by Falconer, in his Observations respecting the Pulse, published in 1796. It will economise time and space to present the general results of these three series of experiments in a tabular form.*\n\tMorning. Evening.\t\tDifference.\nKeill\t80-50\t89-72\t9-22\nBryan Robinson (Pulses of A.)\t70\t76\t6-00\n(Pulses of B.)\t68-50\t78\t9-50\nFalconer -\t69-60\t76\t6-40\nAverage\t72-15\t79-93\t7-78\nThe results of these four series of experiments would appear to furnish a very strong probability in favour of the theory prevailing among the older authorities of an increased frequency of pulse towards the afterpart of the day ; and if all the experiments had been made in full cognisance of the influence of posture and other exciting causes on the pulse, and with a due regard to those circumstances, they would have been quite conclusive. Even as it is, they must be admitted to establish a presumption, if not in favour of a universal law, at least for a general rule, or for a frequent exception to the opposite theory. Some experiments, however, performed by Nickt on his own person, of which part were made in the same manner as those of Robinson and Falconer, and part with the precautions just indicated, would lead us to entertain a doubt whether the older authorities may not have been altogether misled by an erroneous or careless mode of performing their experiments. Nick\u2019s expe-\n* A minute account of the experiments of Robinson and Falconer, and of the literature of this part of the subject of the Pulse, will be found in the Medical Gazette, June 10. 1839. KeilFs observations, from which the averages are calculated, amount to 256 in the morning, and 275 in the evening ; the observations of Bryan Robinson were continued for twelve weeks in the first case, and three weeks in the second; while the observations of Falconer were continued almost daily for more than three months.\nf Op. cit. p. 5\u201413.\nriments, performed in the same manner as those of Keill, Robinson, and Falconer, that is to say, without any unusual precautions, gave, as an average of four series, made on four different days, a pulse of 59 at \u00a7 past 7 a. m. and 64 at midnight ; and as the result of a single series beginning at 5 a. m. and ending at 10 p. m., a pulse of 59 for the first named hour, and 64 for the last. In each of these experiments the pulse was more frequent in the evening by 5 beats. In both these cases the posture was disregarded; but even when, as in Bryan Robinson\u2019s experiments, the sitting posture was preserved in all the observations, but other precautions disregarded, similar results were obtained. Thus, in one instance, the pulse was 66 at 6 a. m., and 71 at 8 p. m. ; and in an average of three series of observations the pulse, which was 70 at 9 a. m., was 72 at a past 10 p.m. In the one case, therefore, There was an increase towards evening of 5, and in the other of 2 beats. When, however, the experiments were conducted still more carefully, the recumbent posture being preserved in all the experiments, all mental and bodily excitement being avoided, no food taken, and the same temperature preserved, an average of six series of observations gave 63\u20198 as the pulse at 8 a. m., and 58 at 7 p. m., being a difference of 5\u20198 beats.\nThe credit of propounding a diminished frequency of the pulse towards the afterpart of the day, as the true theory, is due to Dr. Knox*, who made several series of experiments, in order to establish it. The general results of these experiments with those of the writer, and some facts gleaned from other sources, are thrown together in a table.f\nAs the true state of the case did not seem to be made out even by this balance of authority, it was thought desirable to add to the number of observations. Accordingly several averages of the number of the pulse the first\n* Ed. Med and Surg. Journal, vol. xi. p. 53.1815.\nf The second and third experiments of Dr. Knox were made after dinner and supper respectively. For full particulars of his other experiments the reader is referred either to the original essay or to the Medical Gazette, June, 1839. An account of the writer\u2019s experiments will be found in the Guy\u2019s Hospital Reports, No. viii. Dr. James Saunders\u2019 experiments were not made with any view to this question, but as a preliminary to the effect of digitalis on the pulse (Treatise on Pulmonary Consumption). Except when taking large doses of the drug, the pulse retained in this respect its normal character, being, in three experiments (dose 15 drops twice a day), 70 in the morning and 66 in the evening, and in two experiments (dose 25 drops), 76 in the morning and 70 in the evening ; but when the dose was raised to 50 drops twice a day, the pulse became 80 in the morning and 90 in the evening, and, on the following day, when the dose was again reduced to 25 drops, it remained at the last named numbers. From some experiments on the pulse, which form part of Dr. Prout\u2019s Essay on the quantity of carbonic acid emitted from the lungs during respiration (Annals of Philosophy, vols. ii. and iv. 1813), it would appear that the morning and evening frequency was very nearly the same, the eleven observations in the morning, which correspond with a like number in the evening, giving as averages 70'91 and 70-27.","page":190},{"file":"p0191.txt","language":"en","ocr_en":"PULSE.\n\tMorning.\tNight.\tDifference.\nDr. Knox -\t68-50\t64-38\t4-12\n\t72-00\t64-39\t7-61\nn\t79-33\t63-30\t16-03\n\t79-25\t66-66\t12-59\n\t94-60\t65-78\t28-82\nDr. Nick -\t63-80\t58-00\t5-80\nn\t\u2014\t\u2014\t6-50\nDr. Guy\t64-00\t54-00\t10-00\nDr. James Saunders\t60-00\t56-00\t4-00\nDr. Harden*\t64-00\t62-00\t2-00\nthing in the morning and the last at night, founded on from two to ten observations at each period, in healthy young persons of both sexes, were obtained, with what result will be seen in the following tables.\nSTATE OF THE PULSE, MORNING AND EVENING, IN MALES.\nAge.\tNo. of the Pulse.\t\t\n\tMorning.\tEvening.\tDifference.\n21\t67\t80\t13 in excess\n21\t71\t80\t9\n20\t65\t75\t10\n19\t81\t71\t10 in defect\n27\t63\t61\t2\n15\t92\t85\t7\n18\t82\t73\t9\n22\t76\u00a3\t75\tH\t\nSTATE OF THE PULSE, MORNING AND EVENING, IN FEMALES.\nAge.\tNo. of the Pulse.\t\t\n\tMorning.\tEvening.\tDifference.\n22\t108\t120\t12 in excess\n51\t87\t80\t7 in defect\n26\t91\t81\t10 \t\n14\t99\t81\t18 \t\t\n26\t92\t84\t8 \t\n24\t100\t84\t16\n23\t82\t82\t0\n22\t101\t101\t0\nThe facts contained in these tables and in the previous table, together with the two series of experiments performed by Nick, may be taken to establish the general law first set forth by Dr. Knox, that the pulse is less frequent in the evening than in the morning; but it is obviously subject to numerous exceptions.\nThis law derives some confirmation from the fact that the only series of experiments on females which the writer has met with (those of Friedrich Hohl on pregnant women f) yield averages in conformity with it ; for on comparing the mean of 25 observations made\n* American Journal of Medical Sciences, vol. v. p. 341.\nf Die Geburtsh\u00fclfliche Exploration, bey Anton Friedrich Hohl.\n191\non the pulses of pregnant women in the morning with a mean of the same number made on the same women in the evening, the pulse in the morning was 83\u201828, and in the evening 80 88, being a difference of 2-40. The same author also states that the pulse of the newborn infant, and of the foetus in utero are more frequent in the morning than in the evening.* The interval between the morning and evening is filled up by pulses of very variable frequency, where the experiments are not made with due precaution ; but where, as in the second series of experiments by Nick, and in those of Knox, and of the present writer, the body remains in the same posture, in a state of rest, and unexcited by stimulating food, the fall in the frequency of the pulse is for the most part progressive, and free from those accelerations at noon and in the evening of which Double and Cullen have made mention.\nThe diminished frequency of the pulse towards the afterpart of the day seems to depend altogether on the exhaustion of the strength, and is a less degree of that marked diminution of frequency which often accompanies a convalescence from severe disease. That it is not dependent merely on the absence of exertion ; in other words, that it is not the effect of continued rest, is proved by the facts now to be mentioned.\nIt has been experimentally proved, both by Dr. Knox and by the writer of this article, that the pulse is not only less frequent in the evening than in the morning, but that it is also less excitable. So marked is the difference in this respect, that in some experiments recorded in the Guy\u2019s Hospital Re-portsf, the very same food, which in the morning increased the frequency of the pulse from five to twelve beats, and kept it raised above its natural number from one to two hours, produced no effect whatever in the evening. This fact is in strict keeping with the well known effect of spirituous liquors in the early part of the day, as compared with their action on the system in the evening.\nThe pulse in males appears to follow the same rule in disease as in health. The rule is inverted in females ; but in both sexes the exceptions are very numerous. J\nRest.\u2014From what has already been stated it will be inferred that the absence of exertion has the effect of diminishing the frequency of the pulse.\nSleep.\u2014The pulse falls during sleep, slightly in adults, but considerably in young children. In six observations made by Nick on as many young adults, the mean decrease was somewhat more than three beats. Quetelet, in a girl from three to four years of age, found a\n* An average of twenty-five observations on the morning pulse of the foetus in utero gave 138-08 beats, and on the evening pulse 135-76, a difference of 2-32 beats. Hohl himself recognizes this fact, and distinctly states that the pulse of the f\u0153tus is more frequent in the morning than in the evening.\n-f- No. viii.\nj Ed. Med. and Surg. Journal, No. 146.","page":191},{"file":"p0192.txt","language":"en","ocr_en":"192\tPULSE.\ndifference of 10 beats ; in a boy from four to five years old, 16 beats ; and in a female, in her 27th year, 10 beats. In two pregnant women Hohl observed a difference of 10 and 11 beats respectively ; and the same author reports a difference of from 20 to 40 beats in new-born infants. He also attributes a remarkable decrease of frequency sometimes observed in the foetal pulse to the sleep of the embryo. Other authors have been cognisant of the effect of sleep, but have not made it the subject of experiment.\nFood.\u2014The general effect of food is to excite the pulse; this takes place to a very slight extent with vegetable food, but more with animal food. Some articles of diet, as warm drinks, alcoholic liquors, and tobacco have a very marked influence on the pulse. The effect of food is much more considerable in infancy than in after life. * * * \u00a7\nMental Emotions. \u2014 The effect of these on the pulse is too well known to require any comment.\nTemperature of the Body. \u2014 Cold lowers the pulse, heat quickens it. Exposure to a very high temperature causes a marked acceleration. Thus Sir C. Blagden, on exposing himself for 8 minutes to a temperature of about 260\u00b0, found his pulse rise to 144, or double its ordinary frequency, j*\nDensity of the Air. \u2014 In the observations hitherto made, it is very difficult to separate the influence of this agent from that of the exertion which accompanied the change from one medium to another. There was a very considerable increase of frequency in the case of the men who accompanied Saussure in the ascent of Mont Blanc. The pulses that beat at Chamounix 49, 66, and 72, became, on the summit of the mountain, 98, 112, and 100 respectively. Dr. Clark also found the pulses of his companions, in a state of rest on the summit of the mountain, 84, 84, 88, 92, 102, and 108 respectively, being a considerable increase above the probable frequency of the pulses of the same persons under ordinary circumstances.^ MiillerJ, on the authority of Parrot, gives a table of the frequencies of the pulse corresponding to different elevations. They are as follows : \u2014 Level of the sea, 70 ; 1000 metres, 75; 1500 metres, 82 ; 2000 metres, 90 ; 2500 metres, 95 ; 3000 metres, 100 ; 4000 metres, 110. These numbers are probably unauthorised by experiments.\nThe foregoing are some of the leading causes which affect the frequency of the pulse in health. They may be thrown into two classes ; those which increase, and those which diminish its frequency.\n1. The more common causes of increased frequency of pulse are : \u2014 Exercise, active and passive ; continued muscular effort ; a change from a posture requiring little, to one requiring more exertion ; food, especially warm\n* Experiments of M. Yalleix, Op. cit. p. 336.\nf See Sir David Brewster\u2019s Natural Magic, p. 811.\nX See Auldjo\u2019s Ascent of Mont Blanc, p. 68.\n\u00a7 Physiology, vol. i. p. 163.\ndrinks; spirituous liquors and tobacco; a high temperature; diminished pressure of the air ; extreme debility ; sleeplessness ; the first degree of plethora; and exciting passions and emotions.\n2. The common causes of diminished frequency of the pulse are, \u2014 continued rest; sleep ; fatigue, when not carried to excess ; debility, when not extreme, and unaccompanied by disease ; cold ; increased atmospheric pressure ; a change from the erect to the sitting, and from the sitting to the recumbent posture, and the inverted position of the body; and depressing passions of the mind.\nHitherto we have been speaking solely of that character of the pulse which is most easily examined, \u2014 its frequency. To render the subject complete, it will be necessary to speak briefly of certain other characteristics of the healthy pulse.\nThe pulse of the healthy adult male may be described as regular, equal, moderately full, compressible, and swelling slowly under the finger ; that of the female, and of the child of both sexes, is smaller, and quicker in the beat. The pulse of persons of the sanguine temperament is full, hard, and quick ; that of persons of the lymphatic temperament is softer, and slower in the beat. In old age the pulse, in consequence of the increased firmness of the arteries, assumes a hardness which would not otherwise belong to it.\nExceptions to the general rule are not of very rare occurrence in persons who enjoy good health. \u2014 There are some persons, for instance, in whom every slight attack of indigestion, especially when attended with flatulence, leads to a well marked intermission. Instances are also on record in which the pulse is uniformly irregular or even distinctly intermittent in health, becoming regular in disease, and resuming its irregularity on recovery.\nOne other subject connected with the physiology of the pulse still remains to be examined, viz.\nThe relation of the Pulse to the Respiration. \u2014 The proportion which the pulse bears to the respiration has been variously stated by authors. Quetelet*, Parry j-, Burdach, and the greater number of physiologists estimate it as 4 to 1 ; Joy J as 4| to 1 ; and Floyer as 5 to l.\u00ff M. Valleix states it at 4 to 1 in infants. Little dependence, however, is to be placed upon any of these estimates, as they were made in ignorance of the very remarkable effect of posture on the respiration ; and as the respiration itself was probably counted for very short intervals of time, and under the disturbing influence of a consciousness of the observation which was being made. Though the posture of the body, in which the pulse and respiration were counted, is not distinctly stated by the authors who have put forward the foregoing estimates,\n* Op. cit. Vol. ii. p. 86.\n\u25a0f Pathology, vol. i. \u00a7 890.\nt Library of Practical Medicine, vol. iii. p. 274.\n\u00a7 Pulse Watch, p. 331.","page":192},{"file":"p0193.txt","language":"en","ocr_en":"PULSE.\nit is most probable that it was the recumbent posture; for it is in that posture that the breathing is most easily counted ; and as it is possible, when the subject of the observation is lying down, to place the hand on the abdomen, still retaining the hold upon the wrist, and to count the breathing while he remains unconscious of the object of the observer, the true number of the respirations, as compared with that of the pulse, may be ascertained with tolerable accuracy. Eighteen such observations, made by the writer on as many healthy young men, gave as the average proportion 3*72 to 1, and thirteen observations on as many more healthy and adult females, the proportion of 3*61 to 1. The extremes, in the observations on males, were 2*54 to 1, and 5*33 to 1 ; and in females, 3*10 to 1, and 4*33 to 1. In these observations the respiration was counted, immediately after the pulse, for two consecutive minutes. Bryan Robinson, as the result of three observations on the same number of healthy males in the sitting posture, obtained numbers of the pulse and respiration, from which the calculated proportions are 3*82 to 1, 3' 79 to 1, and 3*86 to 1. Quetelet*, from a series of 300 experiments on males of different ages, obtained the following proportions : \u2014\nAt birth, 3*09 to 1.\n5 years of age, 3*38 to 1.\n15\tto\t20\t-\t-\t3-72\tto\t1.\n25\tto\t30\t-\t-\t4*43\tto\t1.\n30\tto\t50\t-\t-\t3-88\tto\t1.\nIn his own case, the average proportion was 4*19 to 1. From a smaller number of observations on females, the following proportions were obtained : \u2014\nAt birth,\t3-09\tto\tI.\n15 to\t20 years of age, 4*10\tto\t1.\n20 to\t25 -\t-\t4-52\tto\t1.\n30 to\t50 -\t-\t3-92\tto\t1.\nFrom other observations by the same author, it would appear that the proportion of the pulse to the respiration during sleep is lower than in the same persons awake, in consequence of the respiration being more affected during sleep than the pulse. Thus, in a girl from 3 to 4 years of age, the mean proportion of the pulse to the respiration was 3*40 to 1 awake, and 3*68 to 1 asleep ; in a boy from 4 to 5 years old, 3*21 to 1 awake, and 3*50 to 1 asleep ; and in a female in her 27th year, 2*85 to 1 awake, and 3*19 to 1 asleep. The averages are deduced from \u201c un assez grand nombre d\u2019observations\u201d and were probably made in the recumbent posture.\nDrs. Hourmann and Deschambre obtained, as the result of 255 observations on aged females, 3*41 to 1, or, excluding extreme frequencies both in excess and defect, 3-65 to 1. Dr. Pennock, from 146 observations on aged males, obtained a mean of 3*51 to 1, and from 143 observations on aged females, 3*53 to 1.\n* Yol. ii. p. 86.\nVOL. IV.\n193\nAs the respiration is greatly under the control of the will, to obtain the requisite accuracy in observations of this nature it would be necessary to adopt some measures by which it might be counted for several minutes at least in succession, the subject of the observation being either unconscious of what is going on, or having his attention diverted from it. This object the writer has accomplished by converting the common pocket pedometer into an instrument for registering the respirations ; and by means of it, has made several hundreds of observations during periods of half an hour each, the pulse being counted for one or two minutes before and after each registration of the respirations, and the average of the two or four minutes being taken to represent the frequency of the pulse during the whole period of the experiment. The greater number of the experiments were made in the sitting posture, with the back supported, the attention being diverted from the breathing by engaging in study.* The, following are the principal results obtained in this manner: \u2014 the average proportion from 238 experiments performed in the manner just described, the pulse varying from 44 to 85 beats, and the respiration from 15\u00a3 to 20\u00a3, was 3*47 to 1. The extreme proportions were 2*61 to 1, and 5 to 1.\nThe average proportions varied with the number of the pulse, as shown in the following table :\u2014\nNo. of Observations.\tPulse.\tProportion.\n8\t45\u201450\t2*75 to 1\n37\t50\u201455\t3*05 to 1\n50\t55\u201460\t3*31 to 1\n50\t60\u201465\t3*52 to 1\n50\t65\u201470\t3*59 to 1\n27\t70\u201475\t3*82 to 1\n12\t75\u201480\t4*18 to 1\n4\t80\u201485\t4*31 to 1\nFrom the results of these experiments, then, it would appear that the proportion which the pulse bears to the respiration, in the same posture of the body, diminishes as the frequency of the pulse increases.\nAnother fact established by these experiments is the diff\u00e9rent frequency of the respiration morning and evening for the same frequency of pulse. Thus, for a pulse of 63, being an average of 50 experiments in the morning and 50 in the evening, the number of respirations in the morning was 17*60, and in the evening 18*58, being as nearly as possible as the numbers 17 and 18.\nThe effect of posture on the respiration, and the proportion which it bears to the pulse, is, however, still more remarkable than that of the time of the day. Thus, to take the only instance in which it was possible to compare the proportion of the pulse to the\n* An abstract of the results of these experiments was first published in the first part of Hooper\u2019s Physician\u2019s Vade Mecum, edited by the writer early in the year 1842.\no","page":193},{"file":"p0194.txt","language":"en","ocr_en":"194\tQUADRUMANA.\nrespiration in three postures of the body for the same number of the pulse : the pulse being 64, the proportions were : \u2014\nstanding, 2\u201895 to 1. sitting, 3*35 to 1. lying, 4'97 to 1.\nAgain, an average cf 14 experiments, in which the pulse in the sitting and recumbent posture had the same frequency, namely, 62-40, gave the following results :\nsitting, 3*30 to 1. lying, 4\u201839 to L\nThe difference between the erect and sitting posture is less considerable, as will appear from the following average results of six observations, in which the pulse had the same frequency in these two postures, namely, 61*45 :\nstanding, 3*05 to 1. sitting, 3\u201940 to 1.\nThe proportion which the pulse bears to the respiration, therefore, is greater in the erect than in the sitting posture, and in the sitting than in the recumbent posture ; but the difference is greater in the latter than in the former case.\nIf experiments made with great care upon a single individual in the enjoyment of good health may be employed to establish general rules, the following may be laid down in reference to the proportion between the pulse and respiration.\n1.\tThe proportion which the pulse bears to the respiration varies greatly with the frequency of the pulse.\n2.\tThe proportion of the pulse to the respiration decreases as the frequency of the pulse increases.\n3.\tThe proportion of the pulse to the respiration for the same frequency of the pulse is greater in the evening than in the morning ; the respirations in the evening being to those in the morning as 18 to 17.\n4.\tThe proportion of the pulse to the respiration varies in different postures, being higher in the erect than in the sitting, and in the sitting than in the recumbent posture ; the difference between the sitting and the recumbent posture being greater than between the sitting and erect posture.\nSince these results were published, Dr. Harden, of Georgia, U. S., has published an account of some experiments on the pulse and respiration * made on his own person, but without the use of any registering instrument. They are, to a certain extent, confirmatory of the results obtained by the writer. The average number of respirations was as follows Standing, 16; sitting, 14 ; lying, 12 ; the average numbers of the pulse in the same postures, 80, 70, and 66. By selecting from the table published by Dr. Harden five\n* Observations on the Pulse and Respiration, by-John M. B. Harden, M.D., of Liberty County, Georgia. American Joumal of the Medical Sciences, April 1843, vol. v. p. 340.\nobservations, in which the pulse, in each of the three postures, was 68, the following numbers are obtained; \u2014 Respirations, standing, 15-2; sitting, 14-4; lying, 13. The proportions consequently are 4*47 to 1, 4\u201872 to 1, and 5-23 to 1, which follow the same order as the experiments of the writer, though they present smaller differences. The respirations are also more numerous in the evening than in the morning, in the proportion of 13\u00a3 and 13, the pulse being 62 at the former period, and 64 at the latter.\nCalculations founded on the observations of Dr. Pennock, already more than once referred to, confirm the preceding results, as far as the standing and sitting postures are concerned.\nAs the calculations in question serve to exhibit the relation existing between the Pulse and Respiration in advanced age, as well as, by inference, the increasing frequency of the respiration in the aged, they are appended in a tabular form.\nMales.\t\t\nAge.\tSitting.\tStanding.\n50\u201460\t3-71 to 1\t3-68 to 1\n60\u201470\t3-39 to 1\t3-26 to 1\n70\u201480\t3-29 to 1\t3-23 to 1\n80\u201490\t3-07 to 1\t2-96 to 1\n\tFemales.\t\n50\u201460\t-3-65 to 1\t3-61 to 1\n60\u201470\t3-62 to 1\t3-62 to 1\n70\u201480\t3-69 to 1\t3-49 to 1\n80\u201490\t3-46 to 1\t3-29 to 1\n1\t90\u2014115\t2-94 to 1\t2:66 to 1\nThese results are somewhat at variance with those obtained by Hourmann and Des-chambre, who found both the pulse and respiration to increase in frequency with the advance of age, but in consequence of the former increasing more rapidly than the latter, the propoi'tion between the one and the other diminished instead of increasing. The effect of posture on the pulse and respiration was not examined by them ; and it is probable that their observations were made in the recumbent position.\nSuch are the leading results of careful observation on the frequency of the pulse as affected by the more influential natural causes.\nBibliography. The leading monographs and essays which contain well observed facts bearing on the physiology of the pulse, will be found among the references in the foot-notes. The older works are so filled with fanciful conceits, and are so little likely to be referred to, that it has not been thought necessary to give a list of them in this place.\n(William A. Guy.)\nQUADRUMANA. \u2014 The four-handed order of Mammalia, deriving their name from the thumb being opposed to the other fingers and toes, in the feet as well as in the hands, by which peculiarity they are enabled to grasp objects both with their anterior and with their posterior extremities. According","page":194},{"file":"p0195.txt","language":"en","ocr_en":"195\nQUADRUMANA.\nto zoological and zootomical observations, they ought to be divided into two great families, the Simi\u00e6 and the Lemurin\u00e6.\nI. Simi\u00e6. Monkeys. Singes, French. Affen, Germ. Apen, Dutch.\nThis name includes the Quadrumana with four vertical incisor teeth in each jaw, and in general flat and similar nails at the tops of the fingers and toes, two characters by which they approach to man ; the molar teeth have smooth tubercles, and consequently they feed in general upon fruit ; but the canine teeth are stronger than in man, and have their summits not in the same level as the other teeth, but. more prominent. There is consequently, in the same manner as in the Carnivora, an interval in the upper jaw, between the exterior incisor and the canine tooth, in which the canine of the opposed jaw is received. They consist of two distinct groups, of which the first is confined to the old world, and is familiarly known under the name of Apes, Monkeys, and Baboons. These, the anatomical structure of which will be described in the first instance, have the same number of teeth as man, and approach to him in many respects, but differ so much from each other, that it is necessary to divide them into various genera.\n1. Simi\u00e6 ver\u00e6, Monkeys of the Old Continent, Simi\u00e6 catarrliin\u0153 Geoffr. In general the same number of teeth as in man, viz.\n4,\t2 1\t5 5\nincisors-; canines----; molars -----. Nos-\n4\t1\u20141\u2019\t5\u20145\ntrils situated under the nose.\na.\tFirst Genus. Simia. Ape.\nIn general the same number of teeth as in man, but stronger, especially the canine ; an interval between the exterior incisor and the canine in the upper jaw. No callosities on the buttocks ; no tail ; the fore-feet or arms much longer than the hinder. The hair of the head is directed forwards, so as to shade the temples, and that of the fore-arm reverted upwards, in the direction of the elbow, where, encountering the hair of the humerus, which grows in the opposite direction, it stands out in the form of a prominent ruff. They want the cheek-pouches, but possess very large membranaceous expansions communicating with the larynx. In the form of the hyoid bone, in the structure of the .brain, and many other parts of their organisation, they approach the nearest to man. They inhabit tropical Asia and equinoctial Africa.\nSpec. \u2014 Simia troglodytes, Chimpanzee ; Simia Satyrus, Orang-cetan.\nb.\tSecond Genus. Hylobates Illiger. Gibbon,\nFrench. Armaffe, Germ. Langarmige Aap,\nDutch.\nThe same excessive length of the arms, which are so long as to touch the ground, when the animal is in a semi-erect attitude. Callosities on the buttocks, as in the Cerco-pitheci, from which the Gibbons differ by the want of a tail, and of cheek-pouches. The\nform and number of teeth are the same as in Simia and in man, but the crowns of the true molars have a more rounded contour than in the inferior quadrumana, and in their relative size they resemble more the molars of the Carnivora than do those of the genus Simia. The Gibbons are restricted to the forests of tropical India, and their activity in climbing is surprising. They want the laryngeal pouch.\nSpec. \u2014 Hylobates lar, H. variegatus, H. leuciscus, the Siamang (II. syndacty-lus) ought to be separated from the other Gibbons. It has the second and third toe* united by a narrow membrane, extended over the whole length of the first phalanx, and possesses a laryngeal pouch. Its skeleton approaches most to that of man. Its hair is directed as in the Orangs.\nc.\tThird Genus. Semnopithecus F. Cuv.\nSlank-aap, Dutch.\nLong, but slender and straight tail. \u2022{\u2022 They have no cheek-pouches, but they possess a membranaceous, and small laryngeal, expansion. Callosities on the buttocks. Extremities, principally the hinder, very long, as also the fingers and toes, with the exception of the thumb of the hinder hand or foot, which is short, and removed from the outer toes. The slenderness of their body, and largely-developed extremities', enable the Sem-nopitheci to display a great deal of activity. Their stomach is very large, and divided into three or four pouches. The teeth differ from those of the Gibbons by the existence of a posterior tubercle on the last molar teeth of the lower jaw. They inhabit the Indian Continent and the Indian islands, principally Borneo, and are there the constant companions of the Gibbons, with which they have a great analogy.\nSpec. \u2014 Semnopithecus entellus, S. leuco-prymnus (including Simia latibarbata, Ce-phaloptera, and S. Nestor, Benn.), S. leucomystax, S. mitratus, S. niclalophos, S. ru-bicundus, S. chrysomelas, S. maurus, S. fron-tatus, S. nem\u00e6us, S. nasicus. To these could be added, 1. S. cucullatus, but it seems but a local variety of S. leucopvymnus ; 2. S. Sia-mensis, which is a local variety of S. mitratus ; 3. S. flavimanus, which is a local variety of S. melalophos ; 4. \u00bbS'. Sumatranus, local variety of S. chrysomelas ; 5. S. cristatus, variety of S. maurus. S. Muller and H. Schlegel presume that S. albogularis Sykes is a variety of S. entellus; but according to the observations of Ogilby, this monkey is a Cercopithecus. In the enumeration of the\n* According to the observations of Ogilby and F. Cuvier, this character is not exclusive in the Siamang, hut obvious also in many other species of Gibbons.\nf S. Muller and H. Schlegel have proved in their monograph on the genus Semnopithecus, that it is by a mistake that most of the authors on natural, history describe and figure the tail of Semno-pitheci as incurvated in the same manner as in squirrels. It hangs straight below when they climb, and is merely horizontal and touching the ground when they walk.","page":195},{"file":"p0196.txt","language":"en","ocr_en":"QUADRUMANA.\n196\nother species, I followed the direction given by the said authors.\nd. Fourth Genus. Colobus Illiger.\nThis genus represents in North Africa the Semnopitheci of South Asia, and seems only to differ from them by the rudimentary condition of the thumb, and, in one species, C. verus Van Beneden *, by the total want of it. By this disposition the Semnopitheci and Cotobi may be compared with the genus Ateles from the New World, in which some species want the thumb, and others possess it : they seem, in fact, to represent that genus in the Old World, having a great deal of conformity with it in structure, manners, and character. RuppELLf has proved, by dissection of the Colobus guereza, that in this genus the stomach approaches to that of the Semnopitheci, by its extension and the existence of separate cells. The teeth are the same as in the Semnopitheci, viz., with an additional tubercle to the posterior molar of the lower jaw. The first molar of the lower jaw on each side is inclined backwards, and gives also room for the canine of the upper jaw. In both the Semnopitheci and Cotobi, detrition of the molar teeth seems to take place in a longitudinal direction, as has been shown by Ogilby, indicating a corresponding motion of the jaws, something similar to what takes place in the Rodentia. They have cheek-pouches and ischial callosities.\nSpec. \u2014 Colobus polycomos, C. ferrugineus, C. guereza, C. verus.\ne. Fifth Genus. Cereopithecus. Monkey, Engl. Guenon, Fr.\nProminent jaws ; cheek-pouches ; naked callosities on the buttocks, and long but not slender tail ; arms much shorter than the posterior limbs, by which disposition the Cerco-pitheci climb with much agility, but walk with more difficulty : consequently they are sylvan in their habits, and confined in general to the woods of Africa. They possess in general a laryngeal pouch, and their posterior molar of the lower jaw wants in general the additional tubercle proper to the Semnopitheci. The first molar of the lower jaw is disposed as in Colobus, They are quick, capricious, choleric, cunning, and very teachable. They are a pre-eminently sylvan race, and live in the forests in society, under the guidance of the old males. Each tribe or family has its own particular district, into which individuals of other tribes or species are not allowed to intrude. So strongly is this propensity implanted in the Cercopitheci, that they carry it with them even into our menageries. They feed indiscriminately upon wild fruits, the seeds and buds of trees, insects, birds\u2019 eggs, &c., but appear on the whole to be less car-\n* P. S. Van Beneden, Notice sur une Nouvelle Esp\u00e8ce de Singe d\u2019Afrique, tom. v. n. 6. Bull, de l\u2019Acad. Royale de Bruxelles.\n+ E. Ruppell, Neue Wirbelthiere zu der Fauna von Abyssinien. Frankf. a. M. 1835\u20141840.\nnivorous in their appetites than either the Apes or Cynocephali.\nSpec. \u2014 Cereopithecus ruber, C. \u00c6thiops, C. fuliginosus, C. Sabceus, C. griseo-viridis, C. melarhinus, C. fminus, C. pygerythrus. To this genus are also referred the C. mona, C. cephus, C. petaunstus, C. nictitans, and C. Diana, which, according to the observations of F. Cuvier, form a separate group, distinguished by their elegance of form and gentleness of manners and character. All these and the preceding Cercopitheci inhabit chiefly Africa. I intend also to introduce, upon the authority of Ogilby and Schlegel, in this genus three Asiatic and chiefly Indian species, which are referred by others to the genus Macacus, viz., C. cynomolgus, C. radi-atus, and CT. pileatus, Ogilby. They have an additional tubercle on the posterior molar of the lower jaw, and differ by it from the other species of the genus Cereopithecus ; but in their general form, external aspect, and manners, they offer the greatest analogy with the Cercopitheci, constituting a natural group with them, and forming, at the same time, a transition to the genus Inuus. I am fully convinced, that in forming a natural system, it is very wrong to be led by a single anatomical character. This additional tubercle of the molars is unquestionably a subordinate character, insufficient of itself to induce us to separate animals belonging to the same natural group. Geoffroy St. Hilaire seems to have had the same views, by the formation of his genus Cercocebus, in which he places the above-named three species, and Ogilby says that he found in the Man-gabey and in the Collared Mangabey, which every one refers to the genus Cereopithecus, the tubercle in question ; a proof that it is not an essential character. Recently I. Geoffroy St. Hilaire has separated the C. melarhinus or Talapoin from the other Cercopitheci, and has formed of it a new genus Miopithecus. The principal character is the existence of only three tubercles on the posterior molar of the lower jaw. But 1 am of opinion, that this is not sufficient for the formation of a separate genus. If such merely anatomical characters are admitted for the classification of animals, there will be within a short time as many genera as there are animals.\nf. Sixth Genus. Inuus Schlegel. Macacus\nCuv. Macaque, Fr. Laponder-aap, Dutch.\nUpon the authority of my distinguished friend Schlegel*, curator of the splendid museum at Leyden, I am induced to unite the genus Macacus Cuv. with the genus Inuus Schlegel. They form together a natural group, in which the tail becomes gradually shorter, and finally disappears, in the Inuus sylvanus or ecaudatus. An elongated muzzle, much more prominent than in the Cercopitheci, with nostrils opening\n* Ogilby seems to agree with these views, by the formation of his genus Papio, which is much similar to my genus Inuus.","page":196},{"file":"p0197.txt","language":"en","ocr_en":"QUADRUMANA.\t197\nobliquely in its upper part, and a protruded superciliary ridge, give a peculiarly cunning, mistrustful, and somewhat ferocious physiognomy to these Inui, especially to the old ones. Their limbs are strong and compact ; by them, and by the shortness or the want of a tail, they are more a terrestrial than an arborial genus. They devour frogs, lizards, and large insects, as readily as vegetable substances. They possess naked callosities, cheek-pouches, and laryngeal expansions. Their canines are very strong, and the posterior molars of the lower jaw have an additional tubercle. By the great development of the superior canine, the first molars of the lower jaw are inclined backwards on each side, and thus make room for the reception of those teeth. This character appears first in Colobus and Cercopithecus, but it is not so distinct in these as in Inuus. Among the Cercopitheci it is the most apparent in C. cyno-violgus, by which, and by the existence of the additional tubercle on the posterior molars of the lower jaw, this forms, with its two congeners C. radiatus and C. sinicus or pile-atus, a transition to Inuus. This inclined direction of the first molar of the lower jaw becomes more distinct by age. It is rendered necessary, by the length of the superior canine tooth, and by the uninterrupted series of the canine and first molar in the lower jaw. By the action of the superior canine, there is produced a surface for trituration, in the external surface of the anterior root of the first molar.\nThe Inui inhabit generally eastern India. They are very gentle, industrious, and intelligent in their youth, but become ferocious and untameable in their old age.\nSpec. \u2014 Inuus rhesus, I. speciosus, I. ne-mestrinus, I. maurus, I. sylvanus or ecaudatus. Amongst these the I. sylvanus is not only remarkable by the want of a tail, but also by being the only one of this genus which comes within the geographic range of Europe ; great numbers, originally from Barbary, still inhabiting the inaccessible precipices of the rock of Gibraltar.\ng. Seventh Genus. Cynocephalus Cuv. Baboon, Engl. Papion, Fr. B avia an, Dutch.\nThe same teeth as Inuus, but the canini of the upper jaw are enormously developed, and consequently the first molars of the lower jaw are still more inclined. The cheek-pouches, the callosities, and the laryngeal expansions, as in the precedent genera. The tail is either short, thick, and ending in a tuft of hair, or altogether deficient. A large, dog-shaped head, with a prominent, truncated, or, as it were, abruptly cut-off muzzle, with the nostrils opening at the end, gives a hideous aspect to the Cynocephali, corresponding to their ferocious, disgusting, and formidable manners. To the prolongation of the face, and preponderance of the anterior over the posterior part of the head, is to be attributed, at least in a great measure, the fact that the Cynocephali less frequently assume the erect posture than any of the other Quadrumana, and even when\nthey do, are less capable of maintaining it for any length of time. They are essentially constructed for terrestrial progression. Their whole habits, as well as their organic structure, approximate these animals to the ordinary quadrupeds. The great development of their organs of smell ; the position of the nostrils ; the robust make of their extremities, and their equality in point of length ; the size and power of their canine teeth, and the nature of their food ; all indicate their inferiority to the Apes and Monlceys. Their natural food consists of wild berries and bulbous roots, bird\u2019s eggs, insects, &c. In search of food, they go in large companies upon marauding parties, reciprocally to support each other, and to carry off their plunder in greater security. They inhabit principally Africa and the Philippine islands.\nSpec. \u2014 Cynocephalus silenus, C. Sphynx, C. porcarius, C. hamadryas, C. gelada, C. ni-ger, C. leucoph\u00e6us, C. mormon. *\nI refer the C. silenus or Ouanderou to the Cynocephali, by the prevailing authority of Dr. Schlegel. The general physiognomy of this monkey, and the brush at the extremity of the tail, are sufficient characters to justify this determination. The C. silenus forms with the C. niger the link of a chain uniting our genus Inuus with Cynocephalus. In both, the nostrils are not terminal, nor is the muzzle truncated, but disposed as in the Inui, while by the other characters they are Cynocephali. The Gelada, which was first brought to public notice by the celebrated Dr. Ruppell, is certainly a Cynocephalus nearly allied to C. hamadryas. In a skull of this monkey in the museum at Leyden, I was struck with the great conformity it has with the skull of the larger Cynocephali, for example, with the skull of C. porcarius. It has the same prominent superciliary ridges, the same deep orbits, the same prominent maxillary bones, and, above all, the same deep fossa on the facial surface of the supra- and infra-maxillary bones. The Drill (C. leucoph\u00e6us) and Mandrill ( C. mormon) ought to be separated from the rest by a typical pre-eminence. Their cheeks are prominent, deeply ridged, and in the Mandrill beautifully coloured.\nOsteology. \u2014 If we consider the bony framework of all the monkeys of the Old World, we find in it no less numerous differences than in their external form and habits. We may trace in it some successive stages, by which they deviate from the structure of man, and approximate to the skeleton of the larger Carnivora. As I have stated elsewhere, they form an uninterrupted series, in the descending scale, beginning with the Chimpanzee, and ending with the Cynocephali.\nThe skull of the Chimpanzee {fig. 116) is of a narrow, elongated form, slightly contracted\n* Recently I. Geoffroy St. Hilaire has separated the C. gelada under the name of Thecopithecus, and the C. niger under the name of Cynopithecus niger, But I am afraid that the introduction of all these new genera does not constitute an improvement for science.\no 3","page":197},{"file":"p0198.txt","language":"en","ocr_en":"198\nQUADRUMANA.\ntowards the anterior part, which is, as it were, truncated. The cerebral portion, or the cra-\nFig. 116.\nSkull of Simla troglodytes. (After Owen.')\nnium, is smooth, and convex on its superior or coronal aspect, being devoid of the intermuscular frontal and sagittal crests, which give so strong a carnivorous character to the skull of the Orang-cetan. For the insertion of the temporal muscle there is, however, a long boundary continued from the outer part of the supra-orbital ridge, at first as a well-marked crest, but soon becoming a slightly elevated line, which is lost in the lambdoidal and supra-auditory ridges. The coronal suture has a transverse direction ; the occipital foramen is further from the posterior plane of the cranium, and its position is less oblique than in the Orang-cetan. Consequently there is a greater proportion of brain behind the meatus auditorius externus in the Chimpanzee than in the Orang-cetan. Behind the condyle of the lower jaw there is, in the glenoid cavity of the temporal bone, a process, of which the rudiment exists also in man, affording a support for the jaw to guard against a backward dislocation. The frontal bone is single as in man, but distinguished by large projecting supra-orbital ridges, which form a sort of line of demarcation between the cranium and the face. The squamous portion of the occipital bone is of considerable extent, more convex than in the Orang, and consequently more like that of the human subject. The squamous portions of the temporal bone extend over a smaller portion of the sides of the cranium than in man, and their superior margin, instead of forming a convex curve, is almost a straight line. The mastoid processes are represented on either side by a mere ridge of bone, and the styloid processes by small tubercles. The condyloid processes of the occipital bone are proportionally smaller than in the human subject. The foramen magnum is situated in the middle of the posterior third of the basis cranii, and its plane is inclined upwards from the anterior margin at an angle of 5\u00b0 from the plane of the basilar process; there are no posterior condyloid foramina but the anterior condyloid foramina, the foramina jugularia, stylo-mastoidea, carotica, spinosa, and ovalia, are in nearly the same relative position as in man ; the principal difference is in the greater distance between the foramen caroticum and\nthe foramen ovale, in consequence of the greater antero-posterior extent of the petrous bone.\nIn consequence of the proximity of the foramen magnum to the posterior margin of the skull, a considerable extent intervenes between it and the posterior margin of the bony palate ; this is occupied by the large development of the petrous bones, and a corresponding extent of the basilar element of the occipital. The antero-posterior diameter of the bony palate, in like manner, greatly exceeds that of the corresponding part of the human skull. The zygomatic arches are opposite the middle third of the skull, as seen from below, while in the human cranium they are included in the anterior moiety.\nThe form of the basis cramii differs generally from the bimanous, and manifests the quadru-manous type, in its greater length, in its flatness, in the small extent of the receptacle for the brain behind the foramen magnum, in its contraction between the zygomata, and in the large size, and especially the anterior development, of the bony palate.\nA character, by which the Chimpanzee approximates more closely than the Orang to the human subject, is presented by the nasal bone, which projects, in a slightly arched form, beyond the interorbital plane, while a trace of its original separation into two lateral elements remains at the lower margin of the consolidated and single bone.\nThe ascending or nasal portion of the superior maxillary bone, which is of greater proportionate size than in the human subject, does not ascend vertically to the orbits, as in man and some of the lower Quadrumana, but slopes backwards, as in the Cynocephali and in the carnivorous mammalia, but in a less degree. The contour of the upper jaw, from the nasal aperture to the incisor teeth, is almost straight, while in the Orang it is rendered concave by the greater development of the intermaxillary bones in the anterior direction. These bones are anchylosed to the maxillary bones in the adults of both the Chimpanzee and Orang; but in the Chimpanzee the anchylosis takes place at a much earlier period. In the same manner as in man the original separation remains visible, in the palate external to the foraynina incisiva. The lower jaw, like the upper, is equally characterised by its strength and size in relation to the entire skull ; the symphysis or chin recedes ; but the depth of the jaw in front is less than in the Orang-cetan. The ramus of the jaw forms a more open angle with the body than in the Orang-cetan, and thus more nearly resembles the human structure. The dental formula of the Chimpanzee is as I stated before. The teeth approximate in their proportionate size much more nearly than those of the Orang-cetan to the human teeth, but they differ by the absence of unbroken proximity. A well-marked interval separates the upper laniaries from the contiguous incisors, and the lower laniaries are removed by a smaller interval from the contiguous bicuspidcs ; these intervals admit the","page":198},{"file":"p0199.txt","language":"en","ocr_en":"QUADRUMANA.\t199\napices of the large laniaries respectively of the opposite jaw, when the mouth is closed.\nIn the description of all these peculiarities of the skull of the Chimpanzee, I have been somewhat lengthy, wishing to give an abstract of the excellent paper by Owen * ; and I deemed it necessary to do so, because the Chimpanzee may be considered as the typical link of a chain uniting mankind with the lower animals. By the minute exhibition of all its characters, it is evident that it has a great deal of analogy with the form of man, but that, on the other side, it is removed from man by its more imperfect structure. This inferiority becomes gradually more apparent in the skull of the other monkeys, as may be seen by the brief statement of their principal forms.\nIn the skull of the Orang-cetan {fig. 117) Fig. 117.\nSkull of the Orang-cetan. {After Owen.)\nthe approximation to the Carnivora appears principally in the interparietal and occipital crests, which, as I have proved in my Rech. cTAnat. Comp, sur le Chimpans\u00e9, increases with the general growth of the animal ; in the less large interorbital space ; in the sometimes single, sometimes double nasal bone, which never projects, as in the Chimpanzee, beyond the plane of the nasal process of the superior maxillary bones ; in the facial suture of the intermaxillary bone, remaining till the permanent teeth are almost fully developed ; in the more prominent maxillary and intermaxillary bones ; in the stronger teeth ; in the higher and longer lower jaw ; and in the more depressed chin. It is remarkable that the\n* Fearing I might give an inaccurate account, I have employed, for the most part, the very words of that experienced anatomist, feeling persuaded that, especially for a foreigner, it would be difficult to give a more elegant and more accurate description than he has done. I confess myself guilty of the same plagiarism in some other points of the osteology of the Chimpanzee and Orang-cetan.\nanalogy with the human form is more striking in the young than in the old Chimpanzee and Orang-cetan. In the old, the face, and principally the maxillary bones, grow larger, by which the brutish appearance of the skull becomes greater. On the first aspect, this seems a deviation from a general rule, but it is not so; for in the human subject similar modifications of the skull by age may be observed. In advancing age the face of the child becomes gradually larger and higher, and the receptacle for the brain proportionally smaller, in the same manner as in the Orang-cetan, but in a less degree.\nIn the skull of the Siamang {fig. 118), the\nFig. 118.\nSkull of the Siamang. ( Original from the museum, of Prof. G. Vrolik.)\nanalogy with the human form is, in some parts, greater than in the Orang-cetan. The superciliary ridges, and the semicircular boundary for the insertion of the temporal muscle, are much developed, and the skull is very flat, as in the Chimpanzee, but the interorbital space is large, as in the human subject; the nasal bone is double in young animals, single in the old, but much broader than in the Chimpanzee or Orang-cetan ; the facial part of the skull is broad, and not so prominent as in the two preceding species; the chin has a vertical direction and rounded form ; the coronoidal apophysis of the lower jaw is not very high. By all this the skull of the Siamang approaches to that of the human subject, but it shows nevertheless its inferiority by the foramen occipitale magnum being placed more backwards. In this and the other Gibbons a striking character is given, by the swollen appearance of the posterior wall of the orbit, produced by the convexity of the orbital part of the zygomatic bone. The ala magna of the sphenoid bone contributes nothing to the formation of the orbit, being bent backwards. The superior margin of the squamous portion of the temporal bone is straight, as in the Chimpanzee, the Orang-cetan, and, in general, as in all the monkeys.\nThe Semnopitheci form a sort of transition from these anthropomorphous species to the lower monkeys. Their face is not very prominent; the facial suture of the intermaxillary bone continues to exist in the adult, but disappears in the very old; the coronal suture is prolonged in a point between the two parietal\no 4","page":199},{"file":"p0200.txt","language":"en","ocr_en":"200\tQUADRUMANA.\nbones, and meets there the sagittal suture, which is evidently a proof of inferiority, as A. G. Otto indicated a few years ago.* The depressed chin, the narrowness of the interorbital space, the single nasal bone in most of the genus, are the other characters by which the Semnopitheci show their lower rank in the animal kingdojn.\nThis lower rank, however, is much more evident in the Inui, in which the prominent bony muzzle, the elevated superciliary ridges, the depressed forehead, the flat receptacle for the brain, the chin falling backwards, the long and narrow palate, the single nasal bone, approach to the form of many Carnivora, and manifest an evident inferiority. The facial suture of the intermaxillary o-one disappears only in the very old ones. All this is still more apparent in the Inuus sylvanus ( fig, 119),\nFig. 119.\nSkull of Inuus sylvanus. ( Original, Mus. Zool. Soc. Amsterdam.)\nin which the face is more flat and the chin more depressed than in the other species. In the skull of an adult, I found the facial suture of the intermaxillary bone almost obliterated.\nIn no monkeys, after all, the expression of animality is more distinct than in the Cyno-cephali (fig. 120), in which the contracted fore-\nFig. 120.\nSkull of Cynocephalus porcarius. ( Original, Mus. G. Vrolik.)\nhead, the flattened occiput, the formidable canine teeth, the huge jaws, the strong expanded zygomatic arches, the largely developed cranial ridges, the projecting superciliar tuberosities, and the small extension of the cerebral cavity, contribute to form a hideous aspect, principally in the Mandrill, in which\n* A. G. Otto, De rarioribus quibusdam Sceleti humani cum Animalium Sceleto Analogiis, Yratis-lavi\u00e6, 1839, p. 9.\nthe convex supermaxillary ridges give an additional feature to their ferocious appearance. For the description of the skeleton of the monkeys of the old world, we shall select the two extremes, the Chimpanzee and the Mandrill, (figs. 121 and 122). The vertebral column of\nFig. 121.\nSkeleton of the Chimpanzee. (After Owen.)\nthe Chimpanzee presents but few deviations from that of the human subject. The number of true vertebrae is the same, but an additional pair of ribs takes one from the lumbar, to be added to the dorsal or costal series. The spines of the seven cervical vertebrae are simple and elongated, not short and bifurcated as in the human subject ; that of the third vertebra is the shortest, with the exception of the atlas, where the spine is wanting. The bodies of the lumbar vertebrae are proportionally smaller in the Chimpanzee than in man, where they are enlarged in reference to his erect position. This difference from the bi-","page":200},{"file":"p0201.txt","language":"en","ocr_en":"QUADRUMANA.\nmanous type is manifested still more strongly by the narrowness and length of the sacrum, its smaller curvature, and its parallelism with the spine. A peculiarity is observable in the position of the last lumbar vertebra with relation to the iliac bones ; these rise on either side to, and are partially joined with that vertebra, so that it might almost be reckoned as belonging to the sacral series.\nThe false vertebrce, viz. the sacral and coccygeal, are seven in number. Of these, only\n201\nthe first two have their transverse processes fully developed, and united to the iliac bones ; and hence the trunk is less firmly connected with the pelvic arch, and is consequently more in need of additional support from the anterior extremities than in man. This peculiarity, together with the general disposition of the vertebral column of the Chimpanzee, shows that the animal is not designed to walk, as the human subject, on his hinder legs, but that it is chiefly a quadruped.\nFig. 122.\nSkeleton of the Mandrill. ( Original, Mus. Zool. Soc. Amsterdam.)\nIn the same way, the pelvis of the Chimpanzee differs from that of man in all those particulars which characterise the Quadrumana, and which relate to the imperfection of their means of maintaining the erect position. The iliac bones are long, straight, and expanded above the outside, but narrow in proportion to their length ; the posterior surface is concave, for the location of the glutsei muscles ; the anterior surface nearly flat, and stretching outwards, almost parallel with the plane of the sacrum. The whole pelvis is placed more in a line with the spine, than in man ; its superior aperture is elongated and narrow, so that the whole of the sacrum and coccyx is visible on a front view. The tuberosities of the ischia are broad, thick, and curved outwards. The pubic bones are broad and deep, but flattened from before backwards. In this general conformity with the quadru-manous type, there is, however, a provision for a more extended adherence of the glut\u00e6i\nmuscles in a greater breadth of the ilia, between the superior spinous processes, which also incline forwards more than is observable in the lower genera of Sim\u00ef\u0153 ; and it may thence be inferred that the semi-erect position is the most easily maintained in the Chimpanzee.\nIn the Mandrill the general disposition of the vertebral column is much more remote from the form of man, and approximates to the form of the Carnivorous Mammalia. In the cervical vertebrae, the transverse processes have a triangular form, and offer anteriorly a vertical ridge similar to that which appears in most of the Mammalia as a distinct apophysis. In the dorsal vertebrae, the spinal processes of the nine anterior are inclined backwards, of the three posterior forwards : consequently they offer an opposite direction, which is wanted in the vertebral column of the human subject and in the higher genera of monkeys, but which exists generally in the","page":201},{"file":"p0202.txt","language":"en","ocr_en":"202\tQUADK\u00dcMANA.\nfour-footed Mammalia. The same analogy with these appears in the disposition of the lumbar vertebrae. Their number is six or seven, and their articular or oblique processes are bifurcated, and give origin to a styloid process, which serves to increase the strength of the lumbar part of the vertebral column, and is therefore to be found in the greater number of the quadrupeds.\nThere is no true sacrum ; but two or three sacral vertebrae, forming a conical series, are separately united to the iliac bones, in the same manner as in the Carnivora. The pelvis is much more elongated and cylindrical than in the Chimpanzee, and consequently more approximate to the type of the quadrupeds. The iliac bones are very long, but narrow, with a posterior concave, and an anterior convex surface. The pubic symphysis is very long ; the ischiatic tuberosities are curved outwards, broad, and form a semicircular surface for the insertion of the ischial callosities, which serve the Mandrills as a secure and commodious seat, when they are disposed to sleep or repose after the violent and fatiguing motions which they habitually execute. By all these peculiarities it is manifest that the Mandrill is much more remote from man than the Chimpanzee, and a superficial examination of the two skeletons (figs. 121 and 122) will be sufficient to show the great difference existing between them.\nBetween these two extremes are ranged the other genera of Monkeys of the Old World, as I have stated in the above-mentioned book. I take the liberty to refer to it for more details, and principally for the gradual deviation, by which the vertebral column of the Chimpanzee passes, by the intermediate forms of the Orang-cetan, the Gibbons, the Semnopitheci, the Inin, to that of the Cynocephali ; but I think it necessary to make an exception for the Sia-mang, because the anthropo-morphous disposition is more distinct in this ape than in any other, and even more than in the Chimpanzee or Orang-\u0153tan. The ascending processes of the superior surfaces of the bodies of the cervical vertebrae ; the inclination of the spines from the fourth to the ninth dorsal vertebrae ; the number of five lumbar vertebrae ; their increasing strength and breadth backwards ; the form of their transverse and spinal processes ; the true sacrum, and the quite anthropomorphous disposition of the iliac bones, make the vertebral column of the Siamang (as may be seen in fig. 123) approach the most to that of man. The same conformity with man appears in the sternum of the Siamang. It is composed of the same portions as the sternum of man, viz. the manubrium, the body of the bone, and the xyphoidal appendix ; but it is proportionally broader and shorter, and the body consists of two symmetrical parts. In the sternum of the Chimpanzee there is more analogy with the structure in inferior animals. It has a separate manubrium, wanting the semi-lunar incision of that of man. It is connected with a series of osseous segments, and with a xyphoid appendix. In the\nOrang-\u0153tan all these segments, and sometimes also the manubrium, are separated in two symmetrical parts. Consequently it offers the division proper to the sternum of man, in\nFig. 123.\nSkeleton of the Siamang. ( Original, Mus. Vrolik.)\nthe earliest periods of foetal life, but continuing to exist sometimes by deformity, as has been proved by Otto* and Breschet.f In the other Monkeys, and principally in the Mandrill, there is no conformity at all with the sternum of man. The manubrium is\n* Otto, in the above-mentioned pamphlet, t Gl. Breschet, Kech. sur differentes pi\u00e8ces du. Squelette des Animaux Vert\u00e9br\u00e9s; Ann. de Sc. Natur. Ao\u00fbt, 1838.","page":202},{"file":"p0203.txt","language":"en","ocr_en":"QUADRUMANA.\nwanted, and the rest of the sternum composed of as many segments or sternebrae (Blain-ville), as there are true ribs.\nThe form of the ribs has much analogy in the anthropo-morphous Apes with the ribs of man. Their number corresponds with that of the dorsal vertebrae; consequently it is 13 in the Chimpanzee and in the Siamang, 14 in some Gibbons, 12 in the Orang-\u0153tan and in the greater number of the other species of monkeys. They form a very ample and convex thorax in the Chimpanzee, the Orang-\u0153tan, and the Gibbons, which becomes gradually more narrow and compressed in the Semno-pitheci, the Inui, and Cynocephali. In the size and length of the anterior extremities, the Orang-\u0153tan and the Siamang are remote from man, to whom the Chimpanzee approaches a little more. In the Orang-\u0153tan and in the Siamang they are so long that they touch the ground, and in the quadruped position of the trunk the Orang-\u0153tan is forced to curve the hands outwards, and to support itself upon their dorsal surfaces. In the Chimpanzee, sustaining himself in a semi-erect position, they touch the superior third part of the fibula. In the erect position of man they descend not lower than the third inferior part of the thigh. Consequently the Chimpanzee, the Orang-\u0153tan, and the Gibbons, exhibit, as permanent conditions, proportions of the posterior extremities, which in the human subject are transitory, and proper to the early periods of f\u0153tal life. It is, however, according to the observations of Owen, a remarkable fact, that in the young Chimpanzee the lower extremities, instead of being shorter, in relation to the trunk, are longer, their adult proportions arising from the increased development of the trunk and anterior extremities, which are thus made fit for the vigorous acts of climbing.\nIn the Chimpanzee the clavicle exhibits the same sigmoid curve as in man, but the scapula deviates from the human form by being narrower, in proportion to its length, by the spine running more in the direction of the axis of the trunk, and by being situated more towards the middle of the scapula, and more perpendicular to its plane. The acromion process is longer and narrower than in man. In the Orang-\u0153tan the scapula is broader and more analogous to the scapula of man, but its spine is inclined towards the superior costa; its acromion is narrower and clavi-form, and its coracoid process has a greater inclination downwards. This inclination is an indication of inferiority manifested in all the lower species of monkeys, but it is wanted in the Chimpanzee and in the Gibbons, in which the coracoid process has the same direction as in man. That it is an indication of being placed on a lower scale is proved by the fact, that in all the Mammalia with clavicles the same disposition is observed. The humerus is long in the Chimpanzee, and in all the other long-armed Apes, in which also the fore-arm is longer than the humerus, and composed of two bones, radius and ulna,\ncurved in two opposite directions, so that the space existing between them becomes very large. In the Mandrill, and all the other monkeys of the Old World, the disproportion between the anterior and posterior extremities exists no more ; or if there is a disproportion, it is produced by the greater length of the posterior extremities. The humerus and forearm are in them almost of the same length. The hand of the Chimpanzee is composed of the same number of bones as the hand of man ; but the trapezium and trape-zoides are proportionally smaller, while the os pisiforme is of larger dimensions, being nearly equal to the os magnum. The small size of the trapezium evidently relates to the shortness of the thumb, which it supports. The little finger is also shorter, as compared with the other fingers, than in the human subject. The metacarpal bones are chiefly remarkable for their length ; the phalanges, both for their length and their interior curvature. The hand is thus admirably formed for clasping the thick boughs of forest trees. On the sides of the anterior surfaces of the first and second phalanges, there are ridges for the insertion of the ligaments for the tendons.\nThe general opinion is, that the carpus of the Orang-\u0153tan offers the same number of bones as in man and in the Chimpanzee ; but I have proved in my Rech, d\\Anatomie compar\u00e9e sur le Chimpans\u00e9, that there is in the Orang-\u0153tan an additional bone, situated between the two series of carpal bones (fig. 124.), which I found also in the Gibbons, and which seems to exist in all the lower monkeys. De Blain-yille has described it by the name of os interm\u00e9diaire. Its existence in the Orang-\u0153tan, and its absence in the Chimpanzee, are facts of some importance, as they prove that also in this point of organisation the Chimpanzee is superior to the Orang-\u0153tan.\nAnother character of the hand of the Orang-\u0153tan, and of all the other Monkeys of the Old World, is the length and the narrowness of the metacarpus, and the length of the digital phalanges, with the comparative shortness and backward position of the thumb. The sole exception I know is in the Siamang, whose hand represents almost the hand of man, on a more elongated scale. The trapezium is not situated on the same level as the other bones of the carpus ; consequently the thumb, the bones of which are comparatively longer and thicker than in the Chimpanzee or Orang-\u0153tan, can be opposed to the other fingers. The middle finger is the longest, and the metacarpal bones decrease from the index to the little finger in the same manner as in man. In the Mandrill, on the contrary, the four metacarpal bones of the fingers are of the same length, and the middle finger is not longer than the other. Thereby the forehand loses all its analogy with the hand of man, and approaches to the form of the paws in the Carnivora. In the Semnopitheci the thumbs offer a disproportionate shortness, which scarcely surpass the rudimentary form, and prepare us in some","page":203},{"file":"p0204.txt","language":"en","ocr_en":"204\tQUADRUMANA.\ndegree to anticipate its total absence in the to account for that sedateness of character Colobi. This defect necessarily impairs the and indisposition to violent activity for which function of prehension in the Semnopitheci, they are so remarkable, and, according to the views of Ogilby, helps\nFig. 124.\nCarpus of the Orang-\u0153tan. ( W. Vrolik.')\na, scaphoid ; b, semilunar ; c, triquetrum ; d, trapezium ; e, trapezoides ; f os magnum ; g, unciform; h, interm\u00e9diaire bone; i, os sesamoideum for the tendon of the abductor longus pollicis.\nThe femur of the Chimpanzee is slightly bent in the anterior direction, as in the human subject ; the neck of the bone has the same comparative length, but stands out more obliquely to the shaft. The whole of the bone is flatter or more compressed from before backwards. The head of the femur is attached to the acetabulum by the ligamentum teres, which is most remarkable, because it is wanting in the Orang-\u0153tan, and exists in the other monkeys. The tibia in the Chimpanzee is proportionally thicker at the upper end, and the fibula considerably stronger at the lower end than in man ; the interosseous space is wider, and the anterior convexity of both bones may be perceived to be slightly increased. The patell\u0153 are proportionally smaller. The relative size and position of the tarsal bones more nearly correspond to the same in the human subject than is found in any other quadrumanous animals ; but they deviate nevertheless as much as is necessary to produce that position of the foot which is adopted for climbing, viz. on the exterior edge of the foot, with the sole bent up, and inwards. The os calcis is relatively weak, as compared with that of man, being more compressed from one side to the other, and smaller in all its dimensions ; but it projects backwards more than in the Orang-\u0153tan or in the lower Simi\u0153. From the inclination of the tarsus to rest on its outer edge, the os naviculare is further developed downwards, so as to project considerably below the bones of the same row, without inconvenience from pressure on\nthe sole. The internal cuneiform bone has a corresponding inclination, and thus the hallux is attached to the tarsus, in a position best adapted for its being opposed against the other toes. The whole foot of the Chimpanzee is relatively longer and narrower than in man; and the digital phalanges are more inflected towards the sole. All these deviations are still more apparent in the Orang-\u0153tan, as I have stated in my Recherches d\u2019Anatomie comp, sur le Chimpans\u00e9 ; in which 1 compared the anatomical disposition and the physiological action of the foot of the Orang-\u0153tan with those of club-foot (jpes varus). There can be no doubt that this direction of the foot renders it unfit to support the animal upon a level surface, while it is on the contrary very convenient for the action of climbing. For the same reason the hallux or the thumb of the posterior extremities has a great deal of mobility. I saw many times the two Orangs-\u0153tan of our gardens at Amsterdam grasp objects with the hinder hand, scarcely with less agility and ability than with the forehand. The frequency of these movements of the hinder thumb, and the friction it has to support, when the animal climbs, seem to be the cause why its nail and ungual phalanx sometimes become atrophied, as I have proved by many examples, and as may be concluded also from the perusal of the works of Camper, Temminck, Owen, Yosmaer, and Oskamp.\nIn the Siamang, and in the other Gibbons, the foot approaches more to the human than in the Chimpanzee and Orang-\u0153tan. The","page":204},{"file":"p0205.txt","language":"en","ocr_en":"QUADRUMANA.\ncalcan\u00e9um is very strong, and the hinder thumb is, like the hallux of man, the thickest of all the toes. In the other monkeys of the Old World, the hinder hand loses entirely its analogy with the foot of the human subject. The tarsus is long and narrow, and the hallux acquires more and more the form of a small thumb, removed from the other toes, and giving to the foot some resemblance with the hand ; from which the name of four-handed Mammalia or Quadrumana is derived.\nMyology.\u2014 If the osteology of the Monkeys of the Old World affords us the opportunity of making some interesting remarks, their myology will certainly seem not less important. But it will be almost impossible to give an accurate description of their muscles in the small space allowed to me.- I therefore think it proper to confine myself to those statements, by which the same gradual inferiority as in the bony framework may be confirmed, and I beg leave to refer to my H\u00e9ch. d\u2019Anat. comp, sur le Chimpans\u00ea for a more minute description. One of the very striking peculiarities of the myology of the monkeys is the existence of a distinct pla-tysma myoides, which I found in all those I had the opportunity to dissect. It is an important conformity with the structure of man, in whom this muscle represents the larger subcutaneous muscles of the other mammalia.\nThe sterno . cleido-mastoideus offers an incipient indication of a lower station, by the clavicular fascicle being wanting in the Inui and the Cynocephali.\nIn the digastricus maxill\u0153 inferioris there is, especially in the Inui and Cynocephali, a reunion between the two anterior fascicles or ventres, by which the power of-the muscle for the abduction of the lower jaw must be strongly augmented. The other muscles situated between the hyoid and the chin resemble in the Chimpanzee, those of man, but in the other monkeys they show marks of a lower organisation. According to the observations of E. Burdach and myself, the hyo-thyreoideus and hyo-glossus are united in one, in the Inui and the Cynocephali.\nIn the infra-hyoidian muscles, the only difference from man is, that the intermediate tendon of the omo-hyoideus, which exists in the Chimpanzee as in man, disappears in the Inui and in the Cynocephali, and that in these monkeys the inferior portions of the sterno-hyoidei and sterno-thyroidei are united together. In the latissimus dorsi, an interesting transition to the form of the other mammalia is observed, even in the Chimpanzee, by a prolongation attached to the olecranon. It seems connected with the power that must be performed by this muscle, in the action of climbing. According to my observations in various animals, the insertion of this prolongation differs according to the variety of movements, performed by the anterior extremities.\nThe rhomboideus of the Chimpanzee has the same form and situation as in man, but in the Inui and the Cynocephali it goes to the occiput, in which its insertion serves to sustain\n205\nthe head, in the quadruped progressive motion of these animals.\nIn the Inui and in the Cynocephali, but not in the Chimpanzee, there is a conformity with the form of the large Carnivora, in the existence of the acromio-trachelien (Cuv.), acromio-basilaire (Vicq d\u2019Azyr), coming from the transverse processes of the first cervical vertebrae, and inserted into the spine of the scapula. Its function seems to be to bring the scapula more strongly forwards.\nThe pectoralis magnus, p. brevis, subclavius, and serratus anticus magnus of the Chimpanzee, the Orang-aetan, and the Gibbons, resemble those of man. The only difference is that, according to the observations of Sandifort, the pectoralis magnus is divided in the adult Orang-cetan into a large number of fascicles, in the intervals of which are situated the digitiform prolongations of the enormous laryngeal pouch. But in the Mandrill the pectoralis magnus acquires more analogy with the large quadrupeds, by its greater extension, and its separation into three great fascicles, of which one comes from the posterior part of the thorax. In the muscles of the anterior extremities the general distribution and form are the same as in man. An interesting deviation is given by the Hylobates leuciscus, in which the caput breve m. bicipitis takes origin, from the insertion of the pectoralis magnus. Can this peculiarity be connected with the velocity of their movements, when they swing themselves from one branch to another? Du-vaucel affirms that they will on these occasions leap, with comparative ease, to the surprising distance of forty or fifty feet. About the extensor es of the fingers, a lower form may be observed in the extensor digiti indicis, or m. indicator, which is not a separate muscle, but only a portion of the extensor communis. Consequently the fore-finger, or index, must want the so characteristic separate movements, by which we are accustomed to call the attention upon a subject. The imperfection of this muscle is certainly in relation with the lower psychical condition of the animal. In the Inui and the Mandrill the extensores are still more imperfect, by the division of the extensor digiti minimi, which gives a tendinous insertion to the annular or fourth finger. It is, as I showed in my work upon the Chimpanzee, a transition to the form of the Carnivora. The eight muscles of the thumb exist in the Chimpanzee and in the Hylobates leuciscus; but in the Orang-\u0153tan and in the Mandrill the abductor longus and the extensor brevis pollicis are united in their muscular portions, while the tendons remain separate, and in the Inui there is but one muscle, giving two tendons, which are united at their extremities. This is a distinct transition to the form of the Carnivora. I have found this single muscle in all those which possess a thumb. The small muscles of the thumb, viz. the abductor brevis, the flexor brevis, the adductor, and the opponens, exist in all the monkeys of the Old World, but on a smaller scale than in man. They have also","page":205},{"file":"p0206.txt","language":"en","ocr_en":"QUADRUMANA.\n206\nthe three small muscles for the little finger on the opposite edge of the hand. The consequence of all this is, that the hand of the monkeys of the Old World approaches to the perfection of the human hand, from which it differs by the length and the narrowness of the palm of the hand, the length of the fingers, the backward position of the imperfect thumb, and a less variety of movements. For the physiological results which can be derived from this difference, I refer to my R\u00e9ch. d\u2019Anat. comp, sur le Ckimpans\u00e9, p. 34. The muscles of the posterior extremities differ more from those of the human subject. The glut\u0153i are feeble, and inserted very low on the femur; the gracilis is much broader than in man, and inserted very low in the tibia ; the same is the case with the semitendinosus, the semimembranosus, and the biceps femoris. The result of this low insertion must be, that the knee can only be maintained in a bent, and consequently the trunk in a semi-erect attitude.\nThe gastrocnemius and solceus remain separate until their insertion in the calcan\u00e9um, where they unite to form one tendon. They are flatter than in man, and consequently do not form the calf of the leg, which is so characteristic in man.\nThere is a plantaris, as in man. The monkeys seem to be the only brute animals which possess it.\nThe fleccor magnus of the great toe or thumb of the posterior extremities is not confined to this toe, but gives tendons to the other toes. Consequently it combines its action with that of the flexor magnus 4 digit, pedis. The monkeys possess also a flexor brevis, lumbricales, an abductor and adductor hallucis, a flexor brevis, adductor brevis digiti minimi, peron\u0153us longus and brevis, and tibialis posticus. All the muscles on the sole of the foot are more isolated than in man, and consequently they produce more distinct and separate movements for the digits, and principally for the hinder thumb.\nThey have no peron\u0153us tertius, but the tibialis anticus differs from the same in man, by its separation into two fascicles, of which the inner seems to act as a tibialis anticus, while the outer is a long abductor hallucis. I found this disposition in all the monkeys I had the opportunity to dissect, and it is also confirmed by the observations of E. B\u00fcrdach.\nThe last myological peculiarity which I shall mention is, that the tendon of the extensor communis longus quatuor digitorum is surrounded and fixed by a ligamentous loop, about which I can add* the historical peculiarity, that this ligament, hitherto unknown, has been described in the same year, and perhaps in the same month, by A. Retzius in Stockholm, and by myself in Amsterdam.*\n* A. Retzius, Bemerk, ueb. ein Schleuderformiges Band in dem Sinus tarsi des Menschen u. mehrere Thiere in J. Muller, Arch. Berlin, Jahrg. 1841, Th. v. p. 497. W. Yrolik, Rech. d\u2019Anat. Comp, sur le Chimpans\u00e9, p. 22. tab. v. fig. 2.\nNeurology. \u2014 The brain of the monkeys of the Old World represents an imperfect outline of the brain of man. By the form and the number of convolutions, Leuret * proved that it approaches to the brain of the human subject ; but however great this analogy may be, there remains, however, no doubt that there are some typical differences between the brain of man and of the monkeys, and that from the Chimpanzee to the Cynocephali, the gradual tendency to inferiority is as manifest as in the other points of organisation. We still want perfect representations of the brain of the first, but we may supply this defect by drawings of the brain of the Orang-cetan, of which Tiedemann has represented the basis, Sandifort the superior surface, and I a vertical section. (Figs. 125, 126, 127.) If we\nFig. 125.\nBasis of the brain of the Orang-cetan. (.After Tiedemann.)\nFig. 126.\nSuperior surface of the brain of the Orang-cetan. (After Sandifort.)\n* F. Leuret, Anat. Comp, du Syst\u00e8me nerveux consid\u00e9r\u00e9 dans ses rapports avec l\u2019intelligence. Paris, 1839, 8vo.","page":206},{"file":"p0207.txt","language":"en","ocr_en":"QUADRUM AN A.\nFig. 127.\nVertical section of the brain of the Orang-cetan. {After W. Vrolik.')\ncompare these distinct views of the brain of the Orang-cetan with those of the Baboon represented by Leuret * {figs. 128,129,130),\n207\nthe inferiority of these to the Orang-cetan is so manifest, that it needs scarcely any further explanation. In the first instance, it appears that the brain of the Cynocephalus, and, according to the observations of Tiedemann, we could say the same for all the monkeys inferior to the Chimpanzee, the Orang-cetan, and the Gibbons, differs from the brain of man :\n1.\tBy a greater breadth in proportion to the length, and consequently by a less elliptical and more triangular form.\n2.\tBy less development of the hemispheres of the brain, which do not cover the whole cerebellum.\n3.\tBy a smaller number and greater symmetry of the convolutions, and less deep anfractuosities.\n4.\tBy less development of the corpus striatum, thalamus nervorum opticorum, corpus callosum, and septum lucidum.\nFigs. 128, 129, 130.\nViews of the brain of the Baboon. (After Leuret.)\n5.\tBy the want of digitations on the convex margin of the cornu Ammonis.\n6.\tBy the want of the eminentia digitalis (pes Hippocampi minor).\n7.\tBy the disposition of the corpora albi-cantia, which are united in one mass.\n8.\tBy the absence of calculous granulations in the glandula pinealis.\n9.\tBy less development of the cerebellum and of the pons Varolii.\n* F. Leuret, Anat. Comp, du Syst\u00e8me nerveux consid\u00e9r\u00e9 dans ses rapports avec l\u2019intelligence, Paris, 1839, 8vo.\nAll these manifestations of inferiority are not so distinct in the brain of the Orang-cetan, which approaches more to that of man. This approximation consists in :\n1.\tThe more elliptic, and consequently more human-like form of the brain. It is a most interesting fact, that the deviation, in the descending line, begins already in the Gibbons, the brain of which has a more triangular form, and less developed anterior lobes, than the brain of the Orang-cetan.\n2.\tThe larger cerebral hemispheres, which are protracted behind the cerebellum.","page":207},{"file":"p0208.txt","language":"en","ocr_en":"208\tQUADRUMANA.\n3.\tThe existence of two separate corpora mammillaria, which I found also in the Hylob\u00e2tes leuciscus, and which Sandifort represented in the Siamang. But they are in these less developed than in the Orang-cetan.\n4.\tThe presence of digitations on the cornu Ammonis.\n5.\tMore numerous convolutions and deeper anfractuosities.\n6.\tA larger cerebellum.\nIn all these peculiarities, the brain of the Orang-cetan is superior to that of other monkeys, and still more so to that of the Gibbons, which offer otherwise so much analogy with it. The plate of Sandifort, representing the brain of the Siamang, and my dissection of the Hylobaies leuciscus, have proved, that in the Gibbons the convolutions are not so numerous; the anfractuosities not so deep, their symmetry greater ; the cerebral hemispheres less developed ; the cerebellum smaller; the pons Varolii less distinct; the cornu Ammonis without digitations. This greater perfection of the brain of the Orang-cetan is evidently in accordance with the more eminent intellectual faculties of the Orang-cetan, while, according to the observations of Duvaucel and of S. Muller, the Siamang and the other Gibbons are very stupid. But if, on one side, this superiority of the brain of the Orang-cetan, with which the Chimpanzee seems to have a great deal of analogy, cannot be a subject of controversy amongst anatomists, they would however go too far by saying, that the brain of both is in all points similar to that of man. The following differences may be indicated :\n1.\tThe mass of the brain, in proportion to the volume of the body, is less in these Apes than in Man.\n2.\tThe cerebral hemispheres are less developed, and not so much protracted backwards.\n3.\tThe nerves are thicker in proportion to the circumference of the brain.\n4.\tThe convolutions are not so numerous, and the anfractuosities less deep.\n5.\tThe corpus callosum is not so much extended backwards.\nAbout the nerves of the Monkeys, I shall but mention one very interesting modification, which I observed in the nervus accessorius Willisii of the Chimpanzee. It is divided into two branches, as in man, but the internal is not united with the vagus, as it penetrates separately into the larynx. This very peculiar ramification seems to confirm the opinion of Bischoff *, that the internal branch of the n. accessorius Willisii forms partly the n. laryngeus superior. About the organs of sense there is not much to say. The eye approaches much to the eye of the human subject, by the existence of the yellow spot on the retina, but it differs by a more thin sclerotica. Tiie ears of the higher order of monkeys resemble much the same organs in the human subject, from which they differ\n* L. W. T. Bischoff, Nervi accessorii Willisii, Anat. et Physiol. Darmstadii, 1832.\nonly by a less developed lobulus. The tongue is short, broad, and round, as in man, but it becomes long and narrow in the Inui, and still more so in the Cynocephali.\nAngeiology. \u2014 In the distribution of the vessels and the form of the heart, the monkeys of the Old World offer a great analogy with the disposition of the same parts in the human subject. But few differences can be mentioned. In the trunks arising from the arcus aortce, the superior order of monkej's, as the Chimpanzee and adult Orang-cetan, offer the same number and distribution as in Man ; but in the Semnopitheci, the Macaci, and Cynocephali, there is a commencement of a descending scale in the disposition of the A. innominata, which divides into three branches, viz., the right subclavian and the two carotids, in the same manner as in the Marsupials and Carnivora. It is interesting, that I found also this distribution in four young Orangs-cetan, but that Sandifort observed in the adult the human-like division. In the other ramifications, the resemblance to those of man is very great. The plates of descriptive anatomy which I published on the Chimpanzee, will be sufficient to prove the truth of this assertion.\nSplanchnology. \u2014 No parts of the anatomy of the monkeys are, perhaps, more interesting than the pouches of the larynx. I have published a great number of observations about them, by which is proved : 1. that they exist in the Chimpanzee, the Orang-cetan, the Siamang, the Semnopitheci, Cercopitheci, Inui, and the Cynocephali ; 2. that they are larger in the males than in the females ; 3. that they grow with the age of the animal, and are consequently the largest in the most aged ; 4. that they are chiefly a dilatation of the laryngeal ventricles in the Chimpanzee and in the Orang-cetan, but that in the other monkeys they are in direct communication with the cavity of the larynx, by an aperture at the basis of the epiglottis ; 5. and that they are wanting in the Gibbons, the Cercopithecus radiatus, the Cercopithecus mona and Cynocephalusporcarius. It is very difficult to derive any physiological conclusion from all these anatomical statements. The most probable hypothesis seems to be, that these receptacles of air, -frhich send their prolongations between all the muscular fascicles {fig. 131), seem to diminish the specific gravity of the body, in the action of climbing, and that they are consequently passive organs of movement. I have offered this opinion in greater detail in my work upon the Chimpanzee, and I refuted there the opinion that they were connected with the utterance of voice. The other parts of the laryngeal apparatus do not differ much from those of man, with the exception of the hyoid bone, which has much of the human form in the Chimpanzee, in the Orang-cetan, and in the Gibbons, but the basis of which is changed into a convex and elongated shield in the other monkeys, in which the laryngeal pouch opens below the epiglottis.\nIn the form and structure of the heart and the lungs, there is no difference between the","page":208},{"file":"p0209.txt","language":"en","ocr_en":"QUADRUMANA.\t209\nmonkeys of the Old World and the human subject.\nFig. 131.\nLaryngeal pouch of the adult Orang-cetan. (After Sandifort.)\nIn the organs of digestion, there is much * difference to be observed in the various species of monkeys. The Apes, viz. the Chimpanzee, the Orang-cetan, and the Gibbons, offer much resemblance in these organs to those of man. The stomachs of the four young Orangs-cetan, which I dissected, had quite the human form and structure. But in the adult described by Sandifort, the pyloric portion is separated from the cardiac by a very narrow constriction, and the tunics of the pyloric portion are very thick. In the c\u00e6cum the resemblance to man is still more striking, by the existence of a vermiform appendix, which is separated from the intestine by a constriction in the Chimpanzee, is continuous with the intestine in the Orang-cetan, and is very small, and almost rudimental, in the Gibbons. Consequently there is also a descending gradation in this organ, in the same manner as in all the other points of organisation ; for the appendix is wanting in all the other monkeys, in which the c\u00e6cum is moderately large and terminates in an obtuse cone. The stomach of the other species has not the same oblong form in the transverse direction, as the stomach of the Simi\u00e6 and of man, but acquires a more globular form, especially in the Cyno-cephali. In this way it forms a transition to the form of the stomach in the Carnivora. A very interesting deviation is afforded by the Semnopitheci, in which Wurmb, Otto*, and Owen j- found (as I also saw confirmed in the S. maurus) a complicated form and construction of the stomach, viz., its division into three portions : 1. cardiac pouch, with smooth pari-\n\u2022\n* A. W. Otto, lieber eine neue Affenart, den Cerco-pithecus leucoprymnus, in Nov. Act. Acad. C\u00e6s. Leopold. Carol. Nat. Curios, vol. xii. p. 2.\nf R. Owen, on the sacculated form of Stomach as it exists in the Genus Semnopithecus. Trans. Zool. Soc. tom. i. p. 65. The paper of Wurmb is to be found in the Memoirs of the Batavian Society.\nVOL.IV.\netes, slightly bifid at the extremity ; 2. a middle, very wide, and sacculated portion ; 3. a narrow, elongated canal, sacculated at its commencement, and of simple structure towards its termination. This complication of the stomach seems to be connected with the vegetable food of the Semnopitheci, which consists only of fruits, and it is also a repetition of the divisions we find in the stomach of the Pteropi, the Hyrax capensis, the Bra-dypoda, the Cetacea, and in the utmost perfection in the Ruminantia. A curious fact connected with this sacculated division of the stomach is the existence of bezoars in the Semnopitheci. They are said to be smaller and rounder than those produced by the goats, gazelles, and antelopes.\nA similar disposition of the stomach exists in the Colobi. Ruppell observed it in the Colobus guereza, and Owen * said, that in the Colobus polycomos, the sacculation of the stomach is produced by the same modification of the muscular fibres as in the Semnopitheci, combined with a great extent of the digestive tunics. A narrow band of longitudinal fibres traverses the lesser curvature of the stomach, and a second band, commencing at the left or blind end of the cavity, puckers it up in a succession of sub-globular sacs along the greater end. The form and the size of the c\u00e6cum, and the length and disposition of the intestinal canal in the Colobus, equally correspond with those parts in the Semnopitheci. About the urinary and genital organs there are but few peculiarities to observe in the monkeys of the Old World. The urinary organs have the same general disposition proper to the human subject ; the male genital parts differ only by the existence of an ossiculum penis, by the lobulated form of the glans in some species, and by the complicated structure and large development of the vesi-cul\u00e6 s\u00e9minales, especially in the Mandrill.\nIn the female organs, the form and structure of the uterus are interesting: it resembles that of man, and differs from the divided and bicorn uterus of most of the other Mammalia. It is only by a more longitudinal, and we may say a more f\u0153tal form, that the uterus of the monkeys differs from the same organ of the human subject in the adult state; whereas in gestation, parturition, lactation, and in menstruation, the monkeys of the Old World offer a great deal of analogy with mankind, as may be seen in the elegant descriptions which F. Cuvier gives of many species in his Hist. Nat. des Mammif\u00e8res. In the clitoris there is no bone ; at least Leuckart found none in Inuus rhesus, but he observed a bifid clitoris in Cercopithecus sab\u0153us. According to the observations of Gr. Breschet J. van der Hoeven and Schroeder van der Kolk f, the placenta of the monkeys of the\n* R. Owen, Proceedings of the Zoological Society, p. ix. 1841, p. 84.\nf T\u00ffdscheift von Natuurl\u00ffke geschiede nis en-physiologie intgegeven door J. van der Hoeven en W. H. de Yrese, Leyden 1837\u20141888, &c. &c. p. 357. G. Breschet, Rech. Anat. sur la Gestation des\nP\ns","page":209},{"file":"p0210.txt","language":"en","ocr_en":"210\tQUADRUMANA.\nOld World is separated into two lobes, united by vessels. This may be a transition to the cotyledons of the placenta in most of the Mammalia.\nThe Second Group of Simi\u0153 comprehends those of the New World, or Cebin\u0153 (Simi\u0153 platyrrhin\u0153 G. S. Hil), possessing a distinct character in the existence of four additional molar teeth, by which the general number of teeth is thirty-six. Their head is distinguished by a more rounded form, by nostrils situated laterally on a large nose. A long, and in some species a prehensile tail ; the want of cheek-pouches and of callosities on the buttocks ; a smaller and less robust body, and a less malicious but more melancholy character, give a very conspicuous and distinguished physiognomy to this group.\n2.\tCebin\u00e6. Monkeys of the New World.\n-\u2014- ; molars, -\u2014^ = 36.\n1\u20141 6\u20146\nThey ought to be divided into two great divisions, of which the first comprehends those in which the tail is prehensile, viz., capable of grasping branches, so as to perform the office of a fifth extremity. It is naked at its extremity in some species.\na. Cebin\u0153, with a prehensile tail, naked at its extremity.\n1.\tFirst Genus. Mycetes. Alouatte. Singe hurleur,Fr. Howler, Engl. Brul-aap,Dutch.\nPyramidal head, with an elevated inferior jaw, whose branches are very distant, to give room for a peculiar inflation of the basis of the hyoid bone, which communicates with the larynx, and seems to produce the loud and frightful howlings. By this the anterior surface of the neck is swollen up, which, added to their long beard, gives these animals a hideous appearance. The teeth have the general disposition proper to the Cebin\u0153, but the canini are very strong, and therefore the space in the upper jaw between the external incisor and canine tooth is large for the reception of the canine tooth of the lower jaw. The Mycetes are drowsy and lazy in captivity. In their native woods they live in troops, and climb the trees with much agility.\nSpec. \u2014 M. seniculus, M. fuscus, M. niger.\n2.\tSecond Genus. Ateles. Sapajou ordinaire.\nRounded head, with a slightly prominent muzzle. The thumb imperfect, but visible in some, not visible in others. The clitoris so much developed, that it has quite the appearance of a penis, with a channel at its inferior surface. Those, who possess a visible thumb, have been considered by Spix as forming a distinct genus, under the name Brachytele, but I think it not necessary to introduce this\nQuadrumanes, Menu de l\u2019Acad. des Sciences, s. xix. Paris, 1845.\ndivision. The species of the genus Ateles represent in America the Semnopitheci of Asia, and the Colobi of Africa. They have the same slowness of movement, and the same gravity and gentleness of manners. Their progressive motion upon a level surface is very uneasy and unsteady, while they are forced to sustain themselves upon the internal edges of their fore-hands and the external of their hinder-hands. But they climb with much agility, aiding themselves with the prehensile tail, which acts as a fifth extremity. Their teeth resemble those of the genus Mycetes, but the canine are not so strong, and the molar teeth rounder. They all inhabit Guiana and Brazil.\nSpec.\u2014Atelespentadactylus, A. hypoxanihus, A. paniscus, A. arachnoides, A. fuliginosus, A. marginatus.\n3.\tThird Genus. Lagothrix Geoffr. Caparo.\nRounded head, as in the genus Ateles ; a thumb, as in Mycetes, and the tail naked at its extremity, as in both. This genus is only to be found in South America, and chiefly in Brazil. The hyoid bone is not very large.\nSpec. \u2014 Lagothrix Humboldtii, L. canus.\nb. Cebin\u0153, with a prehensile tail covered with hair at its extremity.\n4.\tFourth Genus. Cebus. Sajou. Singe\npleureur, French. Capucyn-Aap, Dutch.\nRounded head and oval face, with a gentle expression. Tail thicker than in the genus Mycetes and Ateles, and less prehensile, curled at its extremity, longer than the body. Teeth not so strong as in these, especially the canine. The Cebi feed upon fruits. Their movements are graceful and gay. Their manners a mixture of sweetness, cleverness, agility, and lubricity. Their voice is a gentle whistle. The determination of the species has caused great confusion. Rengger is of opinion, that some of them are merely modifications by age of the same species. They inhabit principally Guiana.\nSpec.\u2014 Cebus apella, C.fatuellus, C.robustus, C. xantho-sternos, C. capucinus, C. hypoleucus, C. albifrons.\n5.\tFifth Genus. Callithrix. Sagouine, Fr.\nSlender tail ; teeth not prominent, and short canine.* The head more elevated than in Cebus and Pithecia, but smaller, with less prominent zygomatic arches and higher branches in the lower jaws. Consequently there is more room for the reception of a more complicated larynx. Their voice is heavier, and not so whistling as in the Cebi and Pitheci\u0153.\nCallithrix personata, C. amicta, C. cuprea, C. melanochir.\nOne species C. sciurea, or saimiri, ought to be separated from the rest. Wagner makes\n* In his book des Dents des Mammif\u00e8res consid\u00e9r\u00e9s comme Caract\u00e8res Zoologiques, F. Cuvier gives the teeth of this genus as type for the Saki\u2019s by a mistake, which he corrected in art. Saki noir, Hist. Nat. d. Mammif. t. iv. edit, in folio.","page":210},{"file":"p0211.txt","language":"en","ocr_en":"QUADRUMANA.\n211\nof it the genus Chrysothrix. Its tail is not prehensile, but depressed, and often twisted round objects. Its head is flat ; between the two orbits there is but a membranous septum, instead of a bony wall, and the glans penis is round, as in man ; while it is flat, in the form of the head of a mushroom, in the Cebi, which have the penis in continual erection.\n6.\tSixth Genus. Nochthora F. Cuvier. Aotus Humboldt. Dourocouli.\nDiffers only from the genus Callithnx by large nyctalope eyes and ears, which are partly covered by the skin, and by a small face. The species of this genus have nocturnal habits, and a feline physiognomy. They feed not upon fruit, as the precedent species, but on small birds and insects. In their form, nocturnal habits, and great sensibility to light, the Nochthor\u00e6 approach very much to the species of the genus Stenops, from which they differ in their internal structure. Their nails are straight, long, and sulcated. The dental 4\t1 1\nformulais: incisors -, canines ---, molars\n4\ti\u20141\n-\u20147. They inhabit Brazil.\n0\u20140\nSpec. \u2014 Nochthora trivirgata.\n7.\tSeventh Genus. Pithecia. Saki.\nThe characters of this genus consist in the bushy, but short, prehensile, and long tail, the slender body, the large ears, the dense beard in some species, and the straight, but claw-like nails. Their incisor teeth are more prominent than in the genus Cebus. Brazil.\nSpec. \u2014 Pithecia Satanas, P. rufiventris, P. leucocephala, P. inusta.\n8.\tEighth Genus. Hapale. Ouistiti. Sahui.\nThis genus departs more from the typical genera of monkeys of the New World than any other, inasmuch as they have only the same number of teeth as the monkeys of the Old 4\ti ]\nWorld,viz.32: incisors - , canines --7, molars\n4\t1\u20141\n5\u20145\n5\u20145'\nThe nails, by being compressed and\npointed, assume the appearance of claws, except the thumbs of the after-hands, which have flat nails ; but the thumbs of the fore-hands, which have no flat nails, are so slightly separated from the other fingers, that it is not without hesitation that the Ouistitis are called four-handed or Quadrumana. All the species belonging to this genus live in troops in the Brazilian forests, where they spring from bough to bough, more like birds than quadrupeds. They resemble squirrels, whose form they seem to represent in South America, which possesses but one species of squirrels, Sciurus cestuans. Their incisors, canini, and false molars, are sharp and acuminated. The inferior incisor teeth are long, narrow, and prominent. They feed upon insects, eggs, birds. Their^voice is a gentle whistle, which de\nHumboldt* compares to the voice of some birds. He says that their larynx is similar to the inferior larynx of birds, but he did not illustrate this opinion by sufficient anatomical details.\nThe species can be divided into two groups. The first contains those in which the inferior incisors are cylindrical and the tail is annular.\nHapale jacchus, H. penicillatus, II. leuco-cephalus.\nIn the second, the inferior incisors are truncated like the mouthpiece of a pipe, and the tail is not annular.\nH. argentatus, H. midas, H. ursulus, H. labiatus. H. chrysomelas, H. rosalia, II. chrysopygus, H. cedipus.\nOsteology. \u2014 If we take a general survey of these eight genera of monkeys of the New World, we may observe in them, as well as in those of the Old World, an indication of the descending line, by which they pass into the form of the Lemurin\u00e6, and by those into the Insectivora. In this way they constitute a series, which is parallel to that of the monkeys of the Old World, the latter passing into the Carnivora, the former into the Insectivora. The truth of this assertion will be proved by a more minute examination of the skeleton.\nWe shall first consider the skull. J. A. Wagner divided the monkeys of the New World by their skull into two great divisions. The first is a pyramidal skull, in which the height is greater than the length, and in which the occiput has no posterior eminence, and the occipital foramen is situated backwards. To this division belong Mycetes, as eminently characteristic, and, in subsequent gradation, Callithrix, Nochthora, Pithecia, and Lagothrix. The second form of skull is elongated, with a prominent muzzle, a convex occiput, and an occipital foramen, situated at the basis of the skull. Wagner refers to it the Saimiri, offering a typical pre-eminence, and subsequently Hapale, Cebus, and Ateles.\nIn Mycetes {fig. 132) the forehead is ele-\nFig. 132.\nSkull of Mycetes ursinus. {Original, Mus. Vrolik.)\nvated, the face flat and large ; the distance between the two orbits very great; two nasal bones ; the chin very depressed ; the lower jaw high, with distant branches, between\n* A. de Humboldt, Observ. de zoologie et d\u2019anatomie compar\u00e9e. Paris, 1811, vol. i. p. 8.\np 2","page":211},{"file":"p0212.txt","language":"en","ocr_en":"QU ADR UM ANA.\n212\nwhich the inflated hyoid bone is situated. The same character is to be found in the genus Ateles. In Mycetes, Lagothrix, and Callithrix, there is a peculiar round aperture in the orbital portion of the zygomatic bone, which has the appearance as if it were pierced in the bone by a gimlet. Mycetes, Ateles, and especially Callithrix, afford a very striking conformity with Hylobates, in the swollen appearance of the posterior wall of the orbits, produced by the convexity of the orbital part of the zygomatic bone. This is a new addition to the analogy between Hylobates and Ateles. The ala magna ossis sphcenoidei is yet more depressed backwards than in Hylobates. In Cebus (fig. 133) the cranium is elongated,\nFig. 133.\nSkull of Cebus apella. (Original, Mus. Vrolik.)\nand uniformly round. The frontal bone is lengthened to a sharp point, which advances between the two parietals. This is, as I have said before, a manifest indication of a lower rank. The face is not very prominent ; there are two nasal bones ; a distinct intermaxillary bone ; a rounded chin, which recedes. In Callithrix, Pithecia, and Nochthora, the skull has an oblong form, but it resembles very much a small human skull. The single frontal bone has a triangular form, and is distinguished by the convexity of the orbital part. In the Saimiri the septum between the orbits is but membranous, and the interorbital space narrow; the nasal bone is sometimes single, sometimes double ; the intermaxillary bone distinct ; the chin round and prominent ; the muzzle not protruding ; the orbital part of the zygomatic bone wants the opening proper to Ateles, Mycetes, Lagothrix, and the other species of Callithrix. This general resemblance to the human skull is still greater in the Ouistitis. The external tuberosity of the orbit is less marked ; the interorbital septum is osseous ; the muzzle not very prominent; the intermaxillary bone distinct, but obliterated in old age ; the nasal bones broad, short, completely separated, and consequently similar to those of man ; the chin is depressed, but rounded. Notwithstanding this general resemblance to the skull of man, Cebus, Callithrix, and Hapale differ in some essential points from man. The forehead is much narrower, and has its greatest elevation not laterally, but in the middle ; the occipital foramen placed more backwards ; the muzzle more protruding. In the vertebral column of all\nthe Cebin\u0153 there is a manifest inferiority to be seen in the disposition of the cervical vertebrae, in which there are anterior ridges at the transverse processes, in the same manner as in the lower Mammalia. In the Cebi, the spinal process of the second cervical vertebra offers another analogy with the latter, in its elevated form, in its strength, and in its truncated posterior edge. In the Saimiri the tendency to a lower degree of pefection is still greater, by the triangular form of the transverse processes, and in the Ouistitis the spinal processes become long, acute, and directed backwards. The number of dorsal vertebrae varies from 13 to 14, and is consequently in general greater than in the monkeys of the Old World. There is opposite direction between the spinal processes of the three last, and the ten or eleven first dorsal vertebras. The same disposition is observed in the Saimiri, but in the Ouistitis there is only opposition in the spinal process of the last dorsal vertebra. In Ateles and Cebus the number of lumbar vertebrae is five. The styloid processes are plainly indicated, but their spinal processes are inclined forwards, and terminate in a recurved point, in the same manner as in the Carnivora. In the Ouistitis the analogy with the quadruped form is still greater, as the styloid processes are very long. In the Nochthora the number of the lumbar vertebrae is eight, by which it approaches to Stenops. The sacrum is in the Cebin\u0153 a broad quadrangular bone, with acute edges, united only by one of its spurious vertebrae with the iliac bones. Consequently the symphysis sacro-iliaca is less firm than in the higher species of monkeys. At least such is the case in the Cebi, the Ouistitis, and the Saimiri ; but in Ateles I found four spurious sacral vertebrae united with the iliac bones. The iliac bones are in general narrower in the Cebin\u0153 than in the monkeys of the Old World : consequently the pelvis has a more cylindrical form, with a very long pubic articulation, and approaches more to the form of the pelvis in the Carnivora. The caudal vertebr\u0153 of the Cebin\u0153 deserve a separate mention. They are true or spurious vertebrae. The true are but four or five, short and thick. The spurious are the longest, but become shorter at the extremity of the tail. They are only united by the bodies, not by the articular processes. Chiefly remarkable are the inferior spinal processes in the anterior caudal vertebr\u0153, representing the letter V, and forming a canal, in which pass the vessels for the tail. These processes disappear in general in the posterior caudal vertebrae, and in the monkeys with a prehensile tail the posterior vertebrae become round, tubercular bones, imitating a series of small digital phalanges. The thorax of the Cebin\u0153 is compressed, and the ribs do not form the posterior arches, by which the back of man, of the Chimpanzee, and of the Orang-\u0153tan acquire a broad and flat surface, and by which it is possible for these animals and for man to lie at full length on their back. All the","page":212},{"file":"p0213.txt","language":"en","ocr_en":"QUADRUMANA.\t213\nspecies, on the contrary, which possess ischial callosities, the Gibbons among the rest, sleep and repose themselves in a sitting posture, with the arms folded across the knees, and the head reclined upon the breast, or supported by the shoulder. The Cebin\u0153, in which the ischial callosities are wanting, lie down on the lateral surface of their body. The sternum is separated in the Cebin\u0153 into as many segments as there are true ribs ; consequently it has quite lost the analogy with the human subject, which it has in the higher monkeys of the Old W orld. In the anterior extremities, the humerus of Cebus, Nochthora, Saimiri, and Ouistiti, is similar to that of the Carnivora, by an aperture in the internal condyle, serving for the passage of the brachial artery and the median nerve, which are preserved in this manner from compression and injury, by the contraction of the muscles in the climbing motion of these Quadrumana. In the carpus of the Cebin\u0153 there are nine bones, and consequently they possess the intermediate bone, proper, as I have said, to all the monkeys, with the exception of the Chimpanzee. The phalanges of the fingers and the toes are in general very long and incurvated, by which disposition they acquire a greater aptitude to grasp branches of trees, while climbing. In Ateles the fore-hand has quite lost its analogy with the hand of man, by the want of the thumb, which is only represented by an imperfect metacarpal bone. In Ateles hypoxanthus, which has a rudimental thumb, Prince Maximilian says that it consists of two phalanges, of which the first is but half as long as the second. In the Cebi, the fore-hand differs from the hand of man, by the deviation of the thumb, which is situated on the same level as the other fingers, and has the same length as the little finger. The nails are elongated, and acquire really the form of little claws in the Ouistitis. The posterior extremities offer the general character of the posterior extremities in the monkeys ; the thumb of the hind hand is distant, and has a flat nail in the Ouistitis, while on the other fingers there are small claws.\nNeurology. \u2014 The brain of the Cebin\u0153 differs much in the various genera which are referred to this large division of Quadrumana. In the Cebi it is perfect, and approaches much to the brain of man, as may be seen in the drawing given by Tiedemann in his excellent work. But, according to the observations of I. Geoffroy St. Hilaire and of myself*, there are no circonvolutions on the proportionally very large brain of the Ouistitis, and there are but few in the Saimiri, in which the anterior lobes are not so much developed as in the Cebi. To these statements Leu ret f\n* Comptes Rendus, t. xvi. n. 23, 1843, 12 Juin, p. 1236, and Description des Mammif\u00e8res Nouveaux, etc., in Archives du Museum, tom. ii. liv. 4., Paris, 1841, p. 515.\nf Comptes Rendus, tom.xvi.\u2019n. 24. p.1372. Leuckart agrees with these observations of I. Geoffroy St. Hilaire, saying that he found scarcely any\nmade some objections, which have been sufficiently refuted by I. Geoffroy St. Hillaire.\nMyology.\u2014As respects the muscles, those of the tail only deserve a special notice. They are very strong, especially the flexores. By them the Ateles, if it is wounded to death, remains a long time, hanging on his tail. For the same cause its tail is always inflected when in the state of rest. The Cebi sustain their body on it, if they are forced to go on their hinder legs. The other muscles seem not to differ from those of the monkeys of the Old World. The general description of these may be applied to them.\nSplanchnology. \u2014 The soft parts afford no material for such interesting observations as those of the monkeys of the Old World. The larynx wants in general the pouches, which I have described before. There are but two exceptions yet known, one in the Ma-rikina (Hapale rosalia), in which Cuvier and Carus state that they have found a laryngeal pouch, which, according to Cuvier, communicates with the larynx between the thyroid and cricoid cartilages. The second exception is the Ateles paniscus, in which there is a membranous expansion behind the cricoid cartilage. The hyoid bone of Ateles has the form proper to the monkeys of the Old World. In Cebus it approaches more to the form of man, by a more truncated pyramidal and a less convex or scutiform base.\nThe disposition of the laryngeal apparatus in the genus Mycetes deserves a more accurate notice. It is distinguished, as may be seen in fig. 134, by a peculiar tympaniform dilatation of the base of the hyoid bone, by which a repercussion of the exhaled air seems to be produced. A great resonance, effected by the elasticity of the parietes of this bony cavity, must be the result of this repercussion, by which the terrible howlings of these animals are produced.\nUpon the other soft parts of the Cebin\u0153 there is nothing very particular to say. I mention only the structure of the stomach in Ateles and Mycetes, in which, according to the observations of Cuvier and of Prince Maximilian, there is some tendency to the sacculated form of the stomach in the Semnopitheci. This peculiarity confirms all that I have said before about the analogy between Ateles and Semnopithecus. In the organs of generation the length of the clitoris is worth notice, particularly in Ateles and Cebus. According to the observations of Leuckart * it has an\nconvolutions in the brain of Hapale rosalia and jac-chus. Recently I. Geoffroy St. Hilaire has showed to the French Academy two brains of Ouistitis, and has invited the members to verify the three statements which he published, viz., \u201cl\u2019existence de chaque c\u00f4t\u00e9 d\u2019un sillon profond transversal entre le lobe c\u00e9r\u00e9bral ant\u00e9rieur et le lobe moyen ; celle de quelques sillons lin\u00e9aires et superficiels correspondant au trajet des vaisseaux, et l\u2019\u00e9tat lisse de la presque totalit\u00e9 de la surface des h\u00e9misph\u00e8res.\u201d \u2014 Comptes Rendus, n. 714, Ao\u00fbt, 1843, p. 280.\n* F. S. Leuckart, Zoologische Bruchstucke : Stuttgart, 1841, ii. p. 61.\np 3","page":213},{"file":"p0214.txt","language":"en","ocr_en":"214\nQUADRUMANA.\nos clitoridis, which grows larger at its anterior extremity. Rudolphi seems to have been misled by it, in his description of a presumed hermaphroditical monkey. It is very probable that he did not examine an hermaphrodite, but a female Cebus capucinus.*\nFig. 134.\nVertical section of the hyoid bone and larynx of My-cetes seniculus. {After Sandifort.')\nAbout the embyro-genesis of the Cebince Rudolphi published some interesting notices. He observed in the Ouistitis that the ompha-loid vesicle persists till the last period of gestation, and that there are in Hapale, My-cetes, and Cebus two umbilical veins, which unite near the liver.\nAs an appendix to all these anatomical observations about the Cebin\u0153, I join the results of the dissection of Nochthora trivirgata, which I made in the month of July, 1843, in the Zoological Society of London. The stomach has the transversely oblong form proper to the monkeys in general, and not the round form of the Stenops ; consequently the coecal sac is not so ample as in Stenops. The c\u00e6cum terminates in a more elongated c\u0153cal point than in Stenops. It wants cells, as in the greater part of the American monkeys. In the encephalon the hemispheres are larger in their anterior lobes ; they cover almost the whole cerebellum ; the fossa Sylvii is transverse, and very deep ; the mesial lobes are very distinct ; the asymetry between the two hemispheres is not so distinct as in Stenops, by all which characters the brain of the Nochthora trivirgata approaches to the monkeys, and differs from Stenops. The laryngeal ap-\nparatus has a great deal of analogy with that of man; the thyroid cartilage is large and prominent, and has almost the same form as in man. The epiglottis is much developed, particularly at its base. The arytenoid cartilages are much elevated. The rima glottidis is wide. The tongue differs from the same organ in Stenops, in which it is sustained by a triangular and flat cartilage. In the Nochthora, on the contrary, it has the general structure of the tongue of the monkeys, being long and narrow, with isolated pap\u00efll\u00e6. The heart has an oblong form. The first ramifications of the arcus aortce are similar to those of man. The right lung is divided into four, the left into two lobes.\nII. Lemurin\u00e6. Prosimi\u00e6.\nThe second large family of Quadrumana is formed by the Lemurin\u00e6. They have the general aspect of the American monkeys, but their muzzle is lengthened and pointed, and in the hind feet the first toe is the only one armed with a crooked subulated nail, while the other nails are flat. The four thumbs are opposable ; the teeth differ very much in the different genera, but the molars offer in general the pointed and alternating tubercles proper to the Insectivora.\n1. First Genus. Otolicnus Illig. Galago.\nThe teeth of Otolicnus are as follows,\n\u00c6\t.\t1___1\nviz. incisors, \u2014 ; canines, --------; molars,\n4\t1\u20141\n-\u2014- = 36. The inferior incisors are very 6\u20146\tJ\nnarrow and compressed ; they resemble much the teeth of a fine comb, and are entirely united together. The tarsus is very long, by which the hinder extremities acquire a disproportionate size, and produce a jumping motion. Their tail is very bushy; their ears large and membranous ; their eyes very large, and announce their nocturnal habits. Africa.\nSpec. -\u2014 Otolicnus Senegalensis, O. Mada-gascariensis.\n2. Second Genus. Tarsius. Tarsier.\nIncisors, ~ ; canines, J\u2014molars,-- ^ = qa 2\t1 \u2014 1\t6\u20146\nHas the remarkably long hind legs, the large ears and eyes of the preceding genus ; but the interval between their true molars and their incisors is filled up with short acuminated teeth, of which it is difficult to say if they are canine or molar, and the superior middle incisors are very long, and resemble canine teeth. The muzzle is very short. They inhabit the Mollucca islands, and are nocturnal animals, feeding upon insects.\nSpec.\u2014 Tarsius spectrum.\n* Rudolphi, ueber eine seltene Art. des Hermaphroditismus bei einem Affe (Simia capucina) in Abhandl d. Konigl. AJkad. d. Wissensch. in Berlin, in J. 1816\u20141817; Berlin, 1819, 4to. Physik. Classe, p. 119.\nThird Genus. Stenops Illiger. Loris. Singe paresseux, Fr. Spoo/cdier, Dutch.\nThe teeth as in the Lemunn\u00e6 in general, but the external incisors of the upper jaw are very","page":214},{"file":"p0215.txt","language":"en","ocr_en":"QUADRUMANA.\t215\noften wanting. The first molar of the lower jaw on each side is so much acuminated and incurved that it resembles a canine. The muzzle is short and triangular ; the ears small ; large nyctalope eyes, close to each other ; no tail, or a short one, and a long narrow tongue. They feed upon insects. Their habits are nocturnal, and their movements very slow. They inhabit Eastern Asia.\nSpec. \u2014 Stenops tardigradus, S. gracilis, S. javanicus.\nTo these ought to be added the Stenops potto Bosman, coming from the coast of Guinea. It has a short tail and a short index. In a skull of a young Stenops potto, from the Museum at Leyden (fig. 135), the distance\nFig. 135.\nSkull of Stenops potto. (Original, Mus. Leyden.')\nbetween the two orbits is much larger than in Stenops javanicus, tardigradus and gracilis. It is the narrowest in Stenops gracilis, broader in Stenops javanicus, still broader in S. tardigradus, and the broadest in S. potto. In S. potto the circular boundary for the orbits is not so distinct as in other species.\nFourth Genus. Lichanotus Illiger. Indri.\nThe same form of teeth, but they have only two incisors in the lower jaw. This genus has but one species (L. Indri), distinguished by the want of the tail. Madagascar.\n* The dental formula is :\nIncisors, \u2014 ; canines, ? ; molars, \u2014 =30.\nFifth Genus. Semnocebus Lesson. Avahi.\nThe Semnocebus approaches very much to Lichanotus, from which it differs by the existence of a tail, and by the form of its skull. In a skull of the Avahi, Mus. Leyden (fig. 136 ),\nFig. 136.\nSkull of the Avahi. ( Original, Mus. Leyden.)\nI observe a depression on the frontal surface, between the two orbits, which part is, on the contrary, convex in Lichanotus. The muzzle is not so much protruded as in Lichanotus, and more flat on its anterior part, formed by the intermaxillary bones. The teeth are the same in both. Madagascar.\nSpec.\u2014Semnocebus laniger or Avahi.\nSixth Genus. Cheirogaleus.\nAmong the unpublished drawings of Com-merson, Geoffroy St. Hilaire discovered representations of certain Lemur-like animals, which he considers as constituting .a distinct genus. The characters were at first very indistinct ; but we are now acquainted with the external aspect, the skull, and the teeth of this genus. The dental formula is : incisors,\n-\u2014? ; canines, -\u2014- ; molars, ^\u2014^=36. The\nsuperior incisors are situated in two pairs, with a great interval between both. On each side of the upper jaw there is a large canine, with six molars, of which the two first have acuminated crowns, and seem to be spurious molars; the four posterior are tuberculated. In the lower jaw there are six long and narrow proclive incisors, of which the two exterior are the strongest ; a vertical canine on each side ; a spurious- molar with acuminated crown,, and five true tuberculated molars. In the form and the size of the skull, Cheirogaleus has some analogy with Lemur, particularly by a peculiar opening in the zygomatic bone. The muzzle however is not so prominent, and the interval between the orbits smaller. The form of the skull is intermediate between Lemur and Stenops.\nSpec.\u2014Cheirogaleus Commersonii.\nSeventh Genus. Lemur. Mali, Fr. Meer-kat, Dutch.\nr . 4 \u2022\t1-\u20141\t1\t6\u20146 oa\nIncisors, - ; canines,-\u2014- ; molars, -\u2014- \u2014 36.\n4\t1\u20141\t6\u20146\nThe six inferior incisors are compressed and directed forwards ; of the four superior vertical incisors, the two middle are distant from each other; the canine teeth are very acuminated ; the molars acuminated and alternating in each jaw. The ear not much developed. The tail long, bushy, and highly ornamented. The muzzle is very prominent, lengthened, and pointed ; for which reason the French call the Makis Singes' \u00e0 museau de renard, They feed upon fruits, and inhabit chiefly Madagascar.\nSpec. \u2014 Lemur catta, L. macaco, L. ruber, L. mongos, L. albifrons, L. nigrifrons, L. rufus, L. albimanus, L. cinereus.\nThe Lemur murinus, Maki nain ought to be separated from the other Lemurs. It seems a transition to Otolicnus.\nEighth Genus. Galeopithecus. Vliegende-kat,\nDutch.\nThis genus has been considered by Cuvier to belong to the Cheiroptera, but Temminck and De Blainville have perfectly well de-\np 4","page":215},{"file":"p0216.txt","language":"en","ocr_en":"216\nQUADRUMANA.\nmonstrated that it is not a Vespertilio but a Lemur, and that it forms in this way a transition from the Lemurin\u00e6 to the Cheiroptera. The author of the article Cheiroptera in this Cyclop\u0153dia has adopted the same views, and I agree with them, including the Galeo-pithecus in my present paper. The Galeopithecus, then, is a Lemur, with the extremities connected by a bat-like membrane, or, in other words, surrounded by a thin skin, which they support as the framework~ of the umbrella sustains its covering. By this singular structure, the animal while jumping is suspended in the air, yet without the power, as the Bats, of a continued flight. The fingers of the hands are not longer than thoge of the feet, and provided in both with long and sharp incurvated claws. They dwell upon trees in the Indian Archipelago, and feed upon insects, and, perhaps, little birds. They sleep, as the Bats, suspended by their hind legs, with their head downwards. According to the observations of Waterhouse, their dentition is as follows :\nincisors,\n2\u20142 . 0\u20140 \u2014-\u2014; canines,------;\n4\t1\u20141\nfalse molars,\n2 9\t4 4\n\u2014\u2014- ; true molars, ----=34. The form of\n2\u20142\t4\u20144\nthese teeth is very strange. The anterior incisor of each side in the upper jaw is of a small size and compressed form, suddenly dilated above its insertion in the jaw, serrated\nat the edge, and presenting three or four nearly equal denticulations. The second incisor on either side resembles the first false molar in form, and, like that, has two fangs. The first false molar is compressed, of a triangular form, and has the anterior and posterior edges serrated. The second false molar is less compressed than the first, and divided into two nearly equal, acutely pointed, triangular cusps ; the apex of the posterior cusp is directed inwards. The triangular grinding surface of each of the true molars consists of three pointed cusps. The molars of the lower jaw resemble those of the upper, excepting that the position of the three principal cusps is reverted. The false molars are compressed and resemble, in general, their opponents of the upper jaw. The tooth, which represents the canine, is comparatively small, compressed, and considerably expanded at the apex, where it is serrated, having five or six denticulations. The incisors are almost horizontal in their position, compressed, narrow at the base, and suddenly expanded immediately above the base ; each incisor is deeply festooned or subdivided by incisions into slender laviin\u00e6. The incisors and false molars of the lower jaw are detached.\nSpec.\u2014Galeopithecus variegatus.\nOsteology. \u2014 The considerations upon the skeleton of the Lemurin\u00e6 ought to be con-\nFig. 137.\nSkull of Galeopithecus variegatus. (After Waterhouse.')","page":216},{"file":"p0217.txt","language":"en","ocr_en":"QUADRUMANA.\t217\nnected with those upon the Cebince, in which I said that the form of the bony framework passes gradually and in a descending line into the form of the Lemurin\u00e6, and by those into the form of the smaller Carnivora and Insectivora. The truth of this assertion will be proved by the examination of the skull. In all the skulls of the above-mentioned genera of Lemurin\u00e6, the orbits are open posteriorly, and most so in the Galeopithecus {fig. 137), which we shall take as type, and in which there is a large distance between the orbital process of the frontal and of the zygomatic bone united together in Tarsius, Lichanotus, Stenops, Otolic-nus, and Lemur, and forming there a boundary for the open orbit. In all the Lemurin\u00e6 there is a double frontal bone, with two nasal bones, which are universally very long, and protracted to the anterior part of the muzzle, principally in Stenops, in which they form a sort of tube with the intermaxillar bone. The facial suture of the intermaxillar bone is in general distinct. The lacrymal canal is situated not in the orbit, but on the facial surface of the superior maxillary bone ; in Cheirogaleus {fig. 138) and Lemur, there is a regular oval\nFig. 138.\nSkull of the Cheirogaleus Commersonii. ( Original, Mus. Leyden.)\nopening, in the zygomatic bone, similar to that, which I described in Lagoihrix, Mycetes, and Ateles. In the glenoid cavity of the temporal bone there is a vertical ridge to prevent the backward dislocation of the lower jaw. The coronoid process of the lower jaw is very distinct, as in all the animals, in which the orbits are open posteriorly, and the chin is more depressed than in the Monkeys and Cehin\u0153.\nIn the vertebral column the cervical vertebr\u00e6 are seven in number. The anterior vertical ridges of the transverse processes, in the posterior cervical vertebr\u00e6, are more developed than in the Cebin\u00e6, and extended over a larger number of vertebr\u00e6. The spinal process of the epistroph\u00e6us has the quadrangular form with the posterior cutting edge of the Carnivora. In the dorsal vertebr\u00e6, the tendency to the form of the lower orders of Mammalia is still more distinct, firstly in their augmented number, which is in general 13, but increases to 15 or 16 in Stenops. The spinal processes offer the opposite direction which is proper to the inferior orders of Mammalia, excepting in Stenops and Lichanotus, in which they are all inclined backwards. The bodies of the dorsal vertebr\u00e6 are in general all of the same size, and they do not augment, as in the higher order of monkeys of the Old World. In the\nlumbar vertebr\u00e6 there is also an augmentation of number, which varies from 6\u20148 or 9. In Lemur the form and direction of the spinal lumbar processes have much analogy with those of the Carnivora, being incurvated and directed forwards. In Stenops, Otolicnus, and Lichanotus, they have a more quadrangular form. The styloid processes are much developed. The transverse processes are strong, quadrangular, and directed forwards, as in the Carnivora. The sacrum has the form of a large quadrangular bone, with sharp and straight edges, united by one, two, or three spurious vertebr\u00e6 with the iliac bones. The form of the pelvis resembles that of the Carnivora. The iliac bones have two surfaces, an anterior or internal, slightly convex and narrow, a posterior or external, concave and broad. They unite together in a sharp, anterior edge, of which the anterior and inferior iliac tuberosity forms the anterior and inferior termination. The horizontal branches of the pubis are very distant, and make the pelvis pretty large. By this disposition and by the inclination of the pelvis, it resembles very much that of the Carnivora, and especially of the Cercoleptes caudivolvulus, which has so many other points of analogy with the Lemurin\u00e6. The thorax is compressed, but the ribs are not very convex, as in most of the Carnivora. In the Sternum there is scarcely a manubrium, but its body is separated into as many long and narrow segments or Sternebr\u00e6 as there are true ribs. In the scapula, the coracoid process is recurved and directed downwards, as in the Squirrels and other claviculated Mammalia. This is, as I have said before, a distinct manifestation of inferiority. In the humerus there is, in general, an aperture in the internal condyle for the passage of the brachial artery and the median nerve.\nThe fore-arm has a different disposition in the various genera. In most of them it is composed of the two ordinary bones, the radius and the cubitus, of which the radius is in general curved outwards, and the cubitus straight. But in the Galeopithecus, the transition to the form of the Bats appears in the disposition of the ulna, which is imperfect, not prolonged to the carpus, but terminated in a slender filiform extremity, which is united with the radius. In the hand, the quadrumanous type is visible in the thumb, which is separated from the other fingers, even in the Galeopithecus. But in no genus of the Lemurin\u00e6 is the form of the hand so peculiar as in Stenops. Its principal character consists in the shortness of the index, and in the proportional length of the thumb and of the fourth finger, which is the longest. The carpus is composed of the same number of ossicles as in the monkeys of the Old World ; but as I have proved in another paper *, its connexion with the anti-\n* W. Yrolik, Rech. d\u2019Anat. Comp, sur le Genre Stenops d\u2019llliger, in N. Verhand. d. eerste classe van het Koninkl. Nederl. Instituut. Amsterdam, D. ix. 1843.","page":217},{"file":"p0218.txt","language":"en","ocr_en":"218\tQUADRUMANA.\nbrachium is less firm, by which the hand acquires a great deal of mobility, and can be inclined, as I have often observed, not only outwards, but also backwards. With regard to the posterior extremities, the principal deviation is offered by the Tarsius, in which the fibula is but a slender filiform bone, not extended to the tarsus, but terminating on the third inferior part of the tibia, with which it is united. Consequently the tarsal articulation is only united with the tibia. A yet more striking peculiarity is exhibited in Tarsius and Otolicnus by the tarsus, in which the calcan\u00e9um and the scaphoid bone are two long styliform bones, contributing in that way to produce the enormous length of the posterior extremities. In the Stenops there is not so great a deviation from the ordinary form to be observed ; but it is, however, of some interest, that the two Malleoli are very small, and that the astragalus has an oblique direction inwards. The results of this disposition, as I have proved more minutely in the said paper, are a greater mobility of the foot, a direction upwards of its internal edge, and a great interval between the thumb and the other digits.\nMyology. \u2014 I can only mention the muscles of the Stenops, having had no opportunity to dissect the other genera of Lemurin\u00e6. The sterno-mastoideus has a distinct clavicular fascicle, the existence of which is very interesting, while it is not found in some monkeys, nor in any of the mammalia which have no clavicles. In the M. digastricus there is but an indication of intermediate tendon ; consequently the muscle is simplified, and passes into the form it has in the Carnivora, in which it is composed of a single fascicle. Another peculiarity in the muscular system of the Stenops is the existence of the omo-hyoideus, which is wanting in many large Mammalia, but exists in the monkeys, and as my dissection has proved in the Dasyurus, the Ur sus arctos, the Pteropus, and the Opossum. This muscle is also one of the links connecting the genus Stenops with the Quadrumana on one, and with the Carnivora on the other side. The latissimus dorsi gives, in the same manner as in so many other climbing animals, a prolongation to the internal condyle of the humerus. The pectoralis magnus has the length and the strong disposition of fibres, proper to all the quadrupeds. As in them, the clavicular fascicle is not much developed. The disposition of the biceps and brachialis internus is interesting, because it proves that the genus Stenops, and probably the other Lemurin\u00e6, form a transition from the Quadrumana to the Carnivora insectivora. In the same manner as in these, the biceps consists of but one fascicle, which arises from the superior edge of the articular cavity of the scapula, and is inserted into the radius, and the brachialis internus possesses but an external fascicle, which passes to the antibrachium, behind and under the biceps. It is very remarkable, that notwithstanding the want of the internal fascicle of the ^biceps, there is a coraco-brachialis.\nIt is prolonged downwards to the internal condyle of the humerus ; between it and the internal fascicle of the triceps passes the cubital portion of the vascular plexus. This is an exception to the rule, that the existence of a coraco-brachialis is connected with the existence of an internal fascicle of the biceps, and an additional proof that the genus Stenops forms a transition from the Quadrumana to the Carnivora. In the antibrachium the prona-tores and supinatores are very strong. The flexores are the radialis and ulnaris internus, with the palmaris longus. The extensores are the radialis externus longus et brevis, with the ulnaris externus and the extensores of the fingers. For the flexion of the fingers, there is a rudimental flexor superficialis, which is wanting in the Carnivora, and which exists, on the contrary, in the Quadrumana.\nInstead of the abductor magnus and extensor brevis pollicis there is but one muscle, formed by the union of both these muscles. I have shown already that this tendency to simplify is yet observed in the Orang-\u0153tan and in the Mandrill, and more distinctly in the Inui. Besides this the thumb of the Stenops possesses a flexor brevis, an abductor brevis, and an adductor pollicis.\nIn the posterior extremities we observe, first, a very long and very strong psoas, composed of two portions, of which the internal is the strongest. They are united to the iliacus internus and attached to the small trochanter. The sartorius has an oblique direction, and is attached to the internal edge of the tibia. The gracilis is broad and attached lower to the tibia. The rectus femoris, the cruralis, vastus externus and internus have their usual disposition. There is no pectin\u00e6us, but there are three adductores. It is very remarkable that the adductor magnus forms no aponeurotic canal for the passage of the plexiform crural artery, but that this passes only on the superior margin of the adductor magnus, and penetrates in this manner into the popliteal cavity. I have stated the same disposition in the Bradypus didactylus, in which, and also in the Stenops, this deviation seems to be connected with the peculiar ramification proper to the vessels of the extremities, by which they are more preserved from compression, than in the animals, in which the crural artery forms but a single tube. On the posterior surface of the thigh there are a semi-tendinosus, semimembranosus and biceps. The semi-tendinosus is united to the gracilis. The semi-membrano-sus has its own insertion. They descend very low and surround the gastrocnemius. The biceps terminates on the superior part of the tibia with a large muscular fascicle. Theg/*<-t\u00e6us maximus has a large insertion on the thigh, and is inserted very much downwards. On the anterior crural surface there are a tibialis anticus, an extensor magnus and brevis digitorum pedis, and extensor brevis ha/lucis, which has a very oblique direction, and a per-on\u00e6us magnus and brevis. As regards the flexores, I have only to mention the union of the flexor magnus hallucis with the. flexor mag-","page":218},{"file":"p0219.txt","language":"en","ocr_en":"QUADRUMANA.\nnus quatuor digitorum pedis, which are united in the same manner as in the monkeys. They both give tendons to the toes, of which each receives consequently two tendons. The plantar surface of the tendon of the flexor magnus quatuor digitorum give off four lumbrical muscles. Instead of a flexor brevis there are but small tendons, which bifurcate for the passage of the tendons of the flexor magnus hallucis, and \u25a0Hexor magnus quatuor digitorum pedis. The tibialis posticus is very strong. The small muscles of the posterior thumb or great toe are the abductor, the flexor brevis, and the adductor. Their strength is connected with the mobility and with the removed position of the posterior thumb, giving a great deal of agility to the Stenops in his climbing motions.\n219\nNeurology.\u2014The encephalon of the Lemu-rin\u0153 is only known by the dissection of the Lemur mongos and of the Stenops javanicus and tardigradus. Science is indebted for the first to Tiedemann, and for the two last to Schr\u0153der van der Kolk and to myself. The encephalon of Lemur mongos seems superior to that of Stenops, by the larger development of the hemispheres, the greater breadth of the anterior lobes, the more numerous convolutions and deeper anfractuosities, but otherwise they offer the same type. I have minutely described the brain of the Stenops tardigradus in my paper on this animal, and I mentioned there the small development and the asyme-try of the hemispheres (flg. 139), the triangular form of the anterior lobes, the few convo-\njBrain of Stenops tardigradus. (After W. Vrolik.')\nlutions,the shallow anfractuosities, the scarcely indicated/ossa Sylvii, the not prominent pons Varolii, the very thick cerebral peduncles (crura cerebri), the want of corpora candicantia, the short corpus callosum. In all these points the brain of the Stenops is inferior to that of the monkeys, from which Stenops differs also by more imperfect intellectual faculties.\nFor the organs of sense, I mention principally the interesting existence in the Stenops, of the tapetum lucidum in the eye, by which the animal acquires the faculty of reflection of the light, improperly called phosphorescence of the eyes. In general the sensibility of the eye to light is very exquisite. Therefore most Lemurin\u00e6 are nocturnal, and see very well in almost profound obscurity, as is proved by the observations of F. Cuvier, in the Lemur murinus. The ears of Stenops are very large ; the concha deep, the tragus and antitragus elevated, and instead of anthelix there are two prominent and almost parallel cartilaginous plates. The same development of the ear is observed in the genus Otolicnus. This great development in a nyctalope animal is an interesting fact, principally by comparison with the Cheiroptera, in which the same disposition occurs. The tongue of the Stenops offers a strange structure in the existence of a cartilaginous plate, by which it is supported, and the anterior margin of which is denticulated.\nAngeiology.\u2014I only know some peculiarities about the heart and the vessels of the Stenops. It has a rounded and plane form ;\nthe right ventricule is scarcely longer than the left, and terminates in a rounded point. The right auricle is much larger than the left. The distribution of the trunks coming from the arcus aort\u0153 is as in the plurality of Mammalia, viz. three trunks coming from the a. inno-minata, and a separate left subclavian artery. But the most interesting is the ulterior distribution of the arterial and venous vessels in the extremities. Sir A. Carlisle was the first to show, that they form plexuous ramifications, consisting of a large number of narrow cylindrical vessels anastomosing together. Eighteen years ago, I repeated the observations of this excellent anatomist on various animals, and confirmed their veracity against the objections of Oken and Gaimard ; and recently I had again the opportunity to show, that these ramifications exist in three species of Stenops ; that in the same manner as has been proved for the Bradypi, by Schr\u0153der van der Kolk and Otto, they consist not only of arteries, but also of veins ; and that, by dividing in branches, these ramifications become smaller and smaller, and composed of a less number of vessels (flg. 140).\nSplanchnology. \u2014 The stomach has in Stenops a rounded, almost globular form, in which the cardia is near to the pylorus, and the c\u0153cal sac much developed. Consequently the concave margin of the stomach is small, the convex, on the contrary, large ; with these is connected the elongated spleen. This disposition of the stomach, and especially the","page":219},{"file":"p0220.txt","language":"en","ocr_en":"220\tQUADRUMANA.\napproximation of the cardia and pylorus, seem proper to all the Lemurin\u0153, and already pre-\nFig. 140.\nSuperior limb of Stenops tardigradus.\n{After W. Vrolik.')\nsents its first appearance in some Cebid\u0153. The ccecum terminates in an elongated, conic point, which ought not to be confounded with the vermiform appendix of the ccecuro in man\nand in the apes. The c\u00e6cum is very large, and the colon has also a great extension. The colon is in general larger in the Lemurin\u0153 than in the Simi\u0153. It is said by Cuvier to want cells. In Lemur murinus it is short and ample. Duver-noy and Schr\u0153der van der Kolk describe alternating constrictions and expansions in the intestinal canal of Stenops, which, however, I did not find in the three Loris 1 had the opportunity of dissecting.\nAbout the organs of voice and respiration I have, first, to mention the complete osseous disposition of the laryngeal cartilages ; secondly, their small development ; and thirdly, the bifurcated disposition of the epiglottis. All these points are proofs of imperfection, by which may also be explained the total want of voice in Stenops. The hyoid bone is different from the hyoid bone in the monkeys, and approaches to that of the inferior Mammalia. Its body is a transverse arch, slender, and united at the two extremities with the two pairs of horns. The anterior horns are composed of two distinct bones, of which the first is broad and flat, the second long and slender. The thyroid or posterior horns are broad and flat, and melting away with the basis of the bone, while the anterior have a free articulation. The hyoid with its horns has the form of a transversely inclined X, viz. X.\nIn the organs of generation, the narrowness and convoluted disposition of the Fallopian tubes, the length of the vagina, and especially\nFig. 141.\nFemale external organs of generation of Stenop tardigradus. {After W. Vrolik.)","page":220},{"file":"p0221.txt","language":"en","ocr_en":"221\nRADIAL AND ULNAR ARTERIES.\nthe perforated condition of the clitoris, merit our attention. The clitoris is very prominent, and through it passes the urethra. Consequently it has the structure of a penis, of which it is the representative in the female\n{fig-140-\nAs appendix to my paper on the Quadru-mana I think it necessary to mention the Cheiromys psylodactylus or Aye-Aye of Madagascar. This singular animal seems intermediate between the Lemurin\u0153 and Rodentia. It has the teeth of the last, but all the other characters of the first. De Blainville has elucidated them in a learned paper, published a second time in his Osteographie, and he has proved, indeed, that by the general form of the skull, by the situation of the foramen occipitale magnum, and of the lacrymal opening, by the existence of an intermediate bone in the carpus, by the length of the calcan\u00e9um and scaphoid bone, the Cheiromys is indeed a Le-murine animal. But we want a more perfect acquaintance with its organization and with the form and number of its teeth in early age, before it will be possible to determine exactly, where this very rare animal ought to be placed.\nTo complete my anatomical description of the Quadrumana it will be necessary to mention the fossil specimens discovered recently in Europe, India, and Brazil. The European specimen consists in a lower jaw, discovered near Auch in a soil of tertiary formation. It seems to be of a Cercopithecus. The Indian specimen was found in tertiary formation of the mountainous district of the Himmalaya. It is a fragment of a lower jaw, having some analogy with the lower jaw of the Entellus. The third specimen is American, and consists in different bones of fossil Quadrumana, which seem to be of a Cebus much larger than the modern species.\nBibliography. \u2014 Maximilian, Pr. zu Wied., Beitr. z. Naturgeschichte von Brasilien, Weimar, 1826, B. 2. R. P. Lesson, Spec, des Mammif\u00e8res bimanes et quadrumanes, Paris, 1840. J. Geoffroy St. Hilaire, Desc. des Mammif\u00e8res nouveaux ou imparfaitement connus de la Collection du Museum d\u2019Histoire naturelle, in Arch, du Mus\u00e9e d\u2019Histoire naturelle, torn. ii. 4 Liv., Paris, 1841, p. 485. Tem-minck, Monographies de Mammalogie, Leyde, 1835, torn. 2.12e. Monographie sur le Genre Singe, Simia Linn. Blainville, Osteographie, ou Description iconographique compar\u00e9e du Squelette et du Syst\u00e8me dentaire des Cinq Classes d\u2019Animaux vert\u00e9br\u00e9s r\u00e9cents et fossiles. Ogilby, The Menageries, in Libr. of Entert. Knowledge, London, 1838, vol. i. Berichte von der k\u00f6niglichen anatomischen Anstalt zu K\u00f6nigsberg : Jer Bericht von Heinrich Rathke, mit einem Beitrage zur vergleichenden Anatomie der Affen, von Ernst Burdach, K\u00f6nigsberg, 1838. J. A. Wagner, Beitr. zur Kenntniss der warmbl\u00fctige Wirbelthiere Amerika\u2019s, in Abhandl. d. mathem. physik. Class, d. k\u00f6nigl. bayer. Akad. d. Wissensch., M\u00fcnchen, 1837, 2 B. p. 419. Natuurkundige Verhandelingen van P. Camper over den Orang-outang en eenige andere Aapsoorten, Amsterdam, 1782. R. Owen, On the Osteology of the Chimpanzee and Orang-utan : Trans, of the Zool. Soc. of London, vol. i. p. 343, London, 1835. G. Sandifort, Ont-leerkundige Beschryving van een volwassen Orang-\ncetan (Simia Satyrus) in Verhandelingen over de Natuurlyke Geschiedenis der Nederlandsche over-seesche Bezittingen, Leiden, 1840. Herman Schlegel en Sal. Millier Bydragen tot de Natuurlyke Historie van den Orang-\u0153tan in the same Memoirs. E. Tyson, Orang-outang, sive Homo sylvestris, or the Anatomy of a Pygmie compared with that of a Monkey, an Ape, and a Man, London, 1699. T. S. Traill, Observ. on the Anatomy of the Orang-outang in Mem. of the Wernerian Natiiral History Society, vol. iii., Edinb. 1841, p. 1. C. F. Heusinger, Vier Abbildungen des Schedels der Simia Satyrus von verschiedenen Alter., Marburg, 1838. A. Vosmaer, Beschryving van de zoo zeldzame als zonder-linge Aapsoort, genannd Orang-outang van het Eiland Borneo, Amsterdam, 1778. D. L. Osamp, Naauwkeurige Beschryving van den grooten en kleinen Orang-outang, Amsterdam, 1803. W. Vrolik, Recherches d\u2019Anatomie compar\u00e9e sur le Chimpans\u00e9, Amsterdam, 1841. F. Tiedemann, Ic\u00f4nes Cerebri Simiarum et quorundam Animalium rario-rum, Heidelberg, 1821. F. Tiedemann, Him des Orang-outang's mit dem des Menschen verglichen in Zeitschrift f. die Physiologie, Darmstadt, 1827 ;\n2 B. p. 17. C. A. Rudolphi, Ueb. d. Embryo d. Affen u. einige andere Saugethiere, Berlin, 1828. T. S. Leuckart, Ueb. die Bildung d. Geslechtsor-gane insbesondere der a\u00fcsseren einiger Affen in Zoologische Bruchst\u00fccke; Stuttgart, 1841, ii. p. 37. A. W. Otto, Ueb. eine neue Affenart den Cercopithecus leucoprymnus in Nov. Act. C. L. C. nat. Curios, vol. xii. p. 2. R. Owen, On the sacculated Porm of stomach as it exists in the Genus Semno-pithecus, Trans. Zool. Soc. vol. i. p. 65. G. Fischer, Anat. d. Maki, Frankfort am Main, 1804. G. R. Waterhouse, on the Genus Galeopithecus ; Zool. Trans, vol. ii. p. 4. J. L. C. Schroeder van der Kolk, Bydrage tot de Anatomie van den Stenops Kukang in Tydschr. voor Nat. Geschiedenis en Physiologie, D. 8. pi. 277. W. Vrolik, Rech, d\u2019Anatomie compar\u00e9e sur le genre Stenops in N. Verhand. der le Klasse koninkl. nederl. Inst. D. 10. Amsterdam, Oct. 1843.\nTo this bibliography ought yet to be added H. Burmeister, Beitrage zur n\u00e4heren Keuntniss der Gattung Tarsius, Berlin, 1846. I regret that this very valuable work was not published when I wrote my article in 1843.\n(IV. Front.)\nRADIAL AND ULNAR ARTERIES. (Art\u00e8res radiale et idnaire \u2014 Speichenpulsader und Ellenbogenpidsader.') \u2014 The nomenclature of the different branches of the systemic circulation is based upon two principles. According to one of these, the distinction of appellation is grounded upon the tubes themselves ; their different ramifications being designated by as many names, which usually more or less connote the ultimate destination of the vital fluid they contain. Where this method fails, another remains, which, though essentially arbitrary, is yet of the highest importance : a method which, in order to their stricter contemplation by the anatomist, and their more accurate recognition by the surgeon, isolates different lengths of one and the same tube, according to changes in its position and relations with respect to neighbouring parts.\nThe radial and ulnar arteries, whose anatomy is here to be considered, are included in the first of these categories ; being the branches which result from the bifurcation of the artery for the upper extremity. Commencing in their ordinary distribution, opposite and anterior to the elbow joint, they","page":221},{"file":"p0222.txt","language":"en","ocr_en":"222\nRADIAL AND ULNAR ARTERIES.\ncontinue along the whole front of the forearm, each in tolerably close proximity to the bone whose name it bears.* The ulnar, by simply continuing this course, arrives at the hand, but the radial previously turns round the outer side of the wrist to reach the first metacarpal interval, which it perforates. Each now takes a curved course in the palm ; a curve, whose convexity is ^forwards, whose situation \u2014 superficial or deep \u2014 follows that of the artery with which it is more immediately continuous, and which, completed by a branch or branches from its fellow, forms that from the ulnar the superficial, that from the radial the deep, palmar arch.\nSince either of these arches has a share from both vessels, it might at first sight be supposed that we are here presented with a rare peculiarity in the uninterrupted artery traceable from the radial through its palmar arch to the ulnar, or vice vers\u00e2. But their apparent mutual continuity offers no difficulty to the exact nominal definition of each vessel and, obviously, the anastomosis differs from that common to all arteries only in degree: viz., in the greater freedom of communication which is the consequence of the larger size of the branches effecting it.\nThe brachial artery, inclining somewhat forwards in the lower part of its course, so as to gain the angle of flexion of the limb, lies at its termination on the brachialis anticus, where this muscle becoming tendinous, covers the coronoid process of the ulna previously to its insertion into the apex of the rough non-articular surface of this prominence. Here it divides.\nThe radial artery. Its relations. \u2014 The radial artery begins as the outer of the two divaricating branches, and ends as the deep palmar arch : in this course it offers three chief variations of regional anatomy, which will require a separate consideration. The first of these divisions may be regarded as terminating at the lower border of the radius, the second at the superior extremity of the first metacarpal space in the back of the hand, and the third at the point where, after breaking up into the radialis indicis, magna pollicis, and palmaris profunda vessels, the latter of these, lying deeply in the inner side of the palm, unites with the communicating branch from the ulnar artery.\n(a.) In the forearm, the artery is directed at first downwards and externally, but afterwards more vertically, so as to exhibit a slight curve, whose convexity is upwards and outwards. It thus corresponds for a very short distance \u2014 say one third of an inch \u2014to the coronoid process of the ulna, and lies on the brachialis anticus ; but in the whole of the remainder of its length it is related to the anterior surface of the radius, and is situated on the muscles which immediately cover it. Crossing the inner surface of the tendon of the biceps\n* It will be borne in mind, that here, as in all descriptions of this part, the forearm is supposed to be supine, and hanging vertically by the side of the trunk.\nas this sinks toits insertion, it by turns comes into contact with the cellular tissue on the supinator radii brevis, and lies upon the pronator radii teres, as this passes outwards to its insertion ; then for a short distance the radial origin of the flexor sublimis digitorum sustains it, and next the flexor longus pollicis; by the passage of whose muscular fibres inwards to their tendon, it is left opposed to the pronator quadratus, but scarcely touching it from the depth at which this muscle is placed. To its outer side is the tendon of the biceps, and, at first distantly, afterwards more closely, the supinator radii longus, which maintains the relation throughout the remainder of this portion of the vessel : in this situation is also found the musculo-spiral nerve, which descends under cover of the inner border of the muscle, and passes away from the lower part of the artery towards the back of the wrist. To its inner side are suc-sessively, the pronator radii teres in about the upper half of the region, in the lower, the tendon of the flexor carpi radialis ; and beneath this for a very short distance, that of the flexor longus pollicis. The coverings of the artery are merely the integuments and fascia of the forearm, so that in the whole of its length it is comparatively superficial : and the ordinary cellular tissue surrounds the vessel, while two ven\u00e6 comit\u00e9s accompany its course.\nIt may considerably facilitate finding the artery in the living subject, to bear in mind the superficial indices of its course : and from what has been already stated it may be gathered, that in the upper half of this region the vessel is situated in a triangular hollow, whose base is the brachialis anticus in the lower part of the arm, whose outer side is the supinator longus, and whose inner side is the pronator teres. In the lower portion it occupies a linear and comparatively shallow depression, between two tendons whose margins the fingers readily recognise through the skin, viz. that of the supinator longus externally, the flexor carpi radialis internally. A line, therefore, from the inner border of the biceps tendon, to the inferior apex of the triangle, indicates with tolerable accuracy the first subdivision of its course ; while another from this point, parallel and equidistant to the two tendons above named, marks it in the remainder of the forearm.\n(b.) In the wrist. \u2014 This part of the artery is considerably shorter than the preceding, being scarcely one fifth of its length : its direction is downwards and outwards from the front of the forearm to the back and lower part of the wrist. In this course, the vessel lies on the external lateral ligament of the wrist joint, and at its termination on the posterior ligament of the same articulation ; and corresponds to the scaphoid and trapezium bones which are beneath these. It is covered by skin and fascia, and at first situated at some distance from the surface, becomes towards its termination considerably more superficial. In its course it is crossed obliquely","page":222},{"file":"p0223.txt","language":"en","ocr_en":"RADIAL AND ULNAR ARTERIES.\nby three tendons : in the first instance by two of these placed closely side by side, the extensores ossis metacarpi and primi internodii pollicis ; but by the third, the extensor se* cundi internodii, only just before the artery enters the palm : so that between these two crossings, the vessel runs obliquely downward in the bottom of a groove, which is bounded on each side by these tendons, and whose depth is greatly increased by the action of the muscles with which they are continuous. It finally leaves the back of the hand, by passing between the processes of origin of the abductor indicis.\n(e.) In the palm. \u2014 The vessel having perforated the metacarpal space, is situated very deeply in the palm of the hand, beneath the flexor brevis pollicis and the different structures superficial to this muscle ; namely, the tendons of the flexores sublimis and profundus digitorum, with the Iumbricales muscles, the branches of the median nerve, and, above these, the palmar fascia and integuments. Immediately giving off its magna pollicis and radialis indicis branches, it now crosses the palm as the deep palmar arch, or \u201c palmaris profunda,\u201d which, slightly convex forwards, lies on the proximal extremities of the metacarpal bones, and on the interossei muscles between them ; being directed at right angles to them towards the inner side of the hand, and joined in the fourth metacarpal space by the communicating branch of the ulnar, which completes the arterial circle. This latter part is of course uncovered by flexor brevis pollicis, and, just at its junction with the com-municans uln\u00e6, it might almost be considered as covered by the flexor brevis minimi digiti.\nBranches of the radial artery. \u2014 Amid very numerous ramifications, the following are those whose constancy and size require a separate mention.\n(1.) Arteria radialis recurrens. \u2014 This large branch is given off from the outer side of the radial trunk almost immediately upon its origin from the brachial artery, and whilst it is contained in the triangular hollow before referred to. It passes at first downwards, then outwards, and finally upwards ; lying on the supinator brevis and brachialis anticus successively ; and then occupying the groove between the biceps and supinator radii longus muscles, but overlapped by the latter, it terminates in the arm by anastomosing with the superior profunda, which descends to meet it after passing beneath the outer head of the triceps. It has thus a curved course, the convexity of which is directed downwards towards the wrist. Its branches are very numerous, and chiefly supply the muscles with which it is in contact, inosculating with the vessels which they derive from other sources, and with the superior profunda as aforesaid.\n(2.) Arteria superficialis voice, which usually comes off'from the artery just as it leaves the lower border of the radius to turn around the wrist; and, directed almost vertically downwards, proceeds over the annular ligament\nand immediately beneath the integuments, until it arrives at the muscles of the thenar eminence ; amongst or upon which it passes, crossing them at an oblique angle, to join the termination of the palmar artery, or, in other words, to complete the superficial palmar arch. Liable to very considerable though unimportant deviations in its exact position, perhaps one of the most constant is that where the abductor pollicis lies over the vessel, itself placed upon the flexor brevis and opponens muscles. Its varieties in point of size are chiefly connected with the relative proportions of the other arteries, and are deferred to them ; but it is usually a very small branch, and, quite as frequently as not, ends in these muscles without any direct junction with the superficial palmar arch.\n(3.) Arteria anterior carpi radialis.\u2014 This is ordinarily a minute branch which comes off from the radial, either very close to the preceding, or a little above it. It runs directly inwards in contact with the anterior ligament of the wrist joint, or on the radius at a level just above this ; to join with a similar branch from the ulnar on the opposite side of the wrist, and with the terminations of the anterior interosseous artery. It supplies the carpal bones and the articulation.\n(4.) The arteria dorsalis carpi radialis, or posterior carpal branch, is considerably larger than the preceding, and is given off from the radial at a Wer level, generally while the artery lies in the deep groove formed by the tendons of the extensors of the thumb. Its course is, like that of the anterior carpal, directly inwards beneath the tendons of the different fingers; and like it, at about the middle of the wrist, it terminates by uniting with a similar branch from the ulnar arterj% and with the terminal ramifications of the interosseous vessels. Its size and arched shape are usually much more distinct than those of the anterior carpal vessels.\nOther small branches are given off from the radial immediately previous to its entering the palm. Thus an arteria dorsalis pollicis is usually present, and divides, after a short course, into a branch for each side of the thumb ; and there generally exists a similar twig for the radial side of the index fumer, either as a separate branch from the radial artery, or from the ulnar division of the bifurcation just mentioned. A larger branch runs along the interosseous muscle in the second metacarpal space, to divide at its anterior extremity into branches for the opposed sides of the index and middle fingers. The vessels occupying the third and fourth spaces, with the same ultimate distribution, rarely arise from the radial ; more usually they come from the posterior carpal arch, and sometimes from the previous metacarpal vessel, or from a similar ulnar branch lying in the fourth space. All these metacarpal branches unite, at the superior extremity of the interosseous space, with the deep arch by means of its posterior perforating branches ; and at its inferior termination, with the digital branches","page":223},{"file":"p0224.txt","language":"en","ocr_en":"224\nRADIAL AND ULNAR ARTERIES.\nfrom the more superficial arch of the ulnar vessel. Their distribution to the fingers corresponds to that of the arteria dorsalis polli-cis.\nThe arteria magna sen princeps pollicis is the first branch given off from the radial in the palm, and, as its name intimates, it is usually of considerable size. Fi'om the point of its origin it runs downwards beneath the flexor brevis pollicis and tendon of the flexor longus, lying on the metacarpal bone of the thumb, until near the metacarpo-phalangeal joint ; where it divides into two branches, one of which occupies each border of the phalanges, and joins that opposite in the ordinary manner beneath the sentient cushion which forms the extremity of the thumb.\nThe arteria radialis indicis \u2014 also given off beneath the flexor brevis pollicis, runs yet more vertically downwards than the preceding, beneath that muscle and the adductor pollicis, and on the abductor indicis or first dorsal interosseous muscle, to become superficial at their lower borders. Here it gives off a tolerably large communicating branch to the superficial palmar arch of the ulnar artery, and from this point it passes along the radial side of the second metacarpal bone and index finger to its extremity, having a distribution in all respects like that of the digital bi\u2019anches of the palmar arch ; its description is deferred to them.\nFrom the arch itself are given off few branches of any size. Those which proceed downwards, lying on the palmar interossei, are three in number, one for each space, and anteriorly they end by inosculating with the digital branches from the ulnar, like the small twigs already referred to as occupying the same interosseous position on the dorsum of the hand. They have been named \u201c anterior interosseous \u201d branches. The remaining branches of the radial are the posterior perforating,, three twigs which perforate the superior extremity of the same metacarpal spaces, to anastomose on the back of the hand with the posterior carpal and metacarpal branches.\nThe ulnar artery. \u2014 The remaining terminal branch of the brachial is usually much larger than the preceding, with which it is also contrasted by the more linear direction of its course, and by its situation in the different regions through which it passes ; since it occupies the front of the limb from its commencement to its termination, and is placed less superficially in the forearm than in the hand.\nIts relations in the forearm. \u2014 In this part of its course its direction is nearly straight, but with a slight convexity inwards, and it corresponds to the ulna in its whole length. At first lying on the brachialis anticus, by passing downwards and rather inwards, it next comes into contact with the flexor profundus digitorum which covers the bone; and it continues to lie on it to near the annular ligament. Superficial to the vessel are the skin and fascia of the forearm, together with the first layer of the muscles which oc-\ncupy this situation, or the flexors which proceed from the inner condyle ; viz., the pronator radii teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris, successively. It is overlapped by the outer head and border of the latter muscle during about two-thirds of the forearm, being only uncovered where it becomes tendinous ; i*\u00bb this lower part the artery lies external to this tendon, situated between it and the two inner tendons of the flexor sublimis ; structures which would form a very easy guide to its locality during life. Although thus uncovered, the artery is by no means so superficial as was the case with the radial in the same stage ; having in front of it fasci\u00e6 of great strength, and being placed in a deep depression, from the coming forward of the tendon of the ulnar flexor to its insertion in the pisiform bone.\nThe median nerve, which lay to its inner side on the brachialis anticus, crosses the ulnar artery very soon after the origin of the latter, the point of decussation exactly corresponding to the coronoid origin of the pronator radii teres, which slip of muscle lying over the vessel, separates the two structures. The ulnar nerve at its inner side above, where it enters the forearm between the condyle and olecranon, is in close contact with it in the lower half of this region, placed somewhat superficially and to its inner side. The ordinary venae comit\u00e9s accompany the vessel.\nIn the hand.\u2014In this latter part of its course the artery passes over the annular ligament of the wrist, internal both to the pisiform bone and the muscles of the hypothenar eminence ; and next, as the superficial palmar arch, it passes transversely through this part of the hand, crossing superficially to the flexor tendons and the branches of the median nerve, until it arrives at the point to which we conducted the superficialis vol\u00e6, and the communicating branch sent upwards from the radialis indicis ; a point nearly at the inner border of the prominent ball of the thumb. Though placed above the tendons and nerves the artery, however, is far from subcutaneous in any part of its progress ; for while on the annular ligament, fibres from the insertion of the flexor carpi ulnaris into the pisiform bone pass outwards over its surface to join that structure external to the vessel lying on it ; a little further downwards, the palmaris brevis, where present, is also directed inwards in front of it ; and during the remainder of its length, the strong palmar fascia effectually shields it from immediate pressure. The vertical part of the vessel is accompanied by the ulnar nerve, which maintains the relation it had in the lower part of the forearm, and, inferiorly, divides into its digital branches. The arch, like that of the radial artery, previously described, is convex downwards, concave upwards; but it is obvious that its situation is considerably inferior to it, as well as much more superficial. A transverse line across either the middle of the hand or the centre of the metacarpus would tolerably indicate its position, or one continued across","page":224},{"file":"p0225.txt","language":"en","ocr_en":"RADIAL AND ULNAR ARTERIES.\nthe palm from the forcibly extended thumb might be taken as a more accurate guide to this part of the vessel.\nBranches of the ulnar artery. \u2014 The first branches of the vessel are two, which usually come off by a common trunk, but are nearly as often separate at their origin. They are called the arteri\u0153 r\u00e9currentes ulnares anterior et posterior, being so 'named from their taking a recurved course upwards into the arm ; the former in the front of the internal condyle of the humerus, and the latter between it and the olecranon process of the ulna. The anterior recurrent passes upwards from beneath the flexor muscles which cover the artery where it rises, lying on the brachialis anticus, and corresponding to the elbow joint which it partially supplies ; its superior termination inosculates with the lowest or anastomotic branch of the brachial. The posterior recurrent, having at first similar relations, passes more inwards so as to reach the above interval, being situated beneath the flexor carpi ulnaris, and meeting the ulnar nerve descending from the arm between the two heads of this muscle. Here it breaks up, anastomosing freely with the inferior profunda which has hitherto accompanied the nerve, uniting also by small branches with twigs sent downwards from the superior profunda in the substance of the triceps, and giving many branches to the articulation and the neighbouring muscles.\nThe next considerable branch is the arteria interossea, which diverges from the trunk of the vessel a little below the coronoid process, and whilst it is covered by the flexor muscles. Directed downwards from its origin, after a course of about an inch in length, it reaches the interosseous membrane in the upper part of the interval between the flexor longus pollicis and the flexor profundus digitorum, and here it bifurcates into two branches. One of these, the anterior interosseous, continues on the front of this membrane, lying deeply in the interval between the two muscles and concealed by them, until, arriving at the pronator quadratus which lies transversely across the lower extremities of the radius and ulna, it passes under this muscle. At its inferior border it reappears, though much diminished in size, and now situated on the anterior ligament of the wrist, it divides into many small branches, which supply the articulation and anastomose with the anterior carpal twigs from the radial and ulnar vessels. In this course, the branch now described supplies the muscle on each side of it, and usually it gives off one or two small branches which perforate the interosseous membrane beneath it in their passage backwards to the posterior region of the forearm. One of these, by far the largest and the most constant, is frequently named as \u201c the posterior branch of the anterior interosseous;\u201d and it escapes to the back of the forearm, through an aperture which exists in the interosseous membrane, near its inferior border, and about an\nVOL. IV.\n225\ninch and a half above the radio-ulnar articulation.\nThe posterior interosseous, the remaining division of the artery, leaves the front of the limb by passing between the radius and ulna above the superior border of the interosseous membrane, and next becomes visible in the back of the forearm, between the inferior border of the supinator brevis and the extensor ossis metacarpi pollicis. In the remainder of its extent it lies on the muscles which arise from the posterior surface of this membrane, and beneath the more superficial layer of extensors and supinators, until it arrives at the wrist. Here, lying on the posterior ligament of the joint, it breaks up into its terminal ramifications, which inosculate freely with the posterior carpal arteries of the radial and ulnar, and with the perforating-branch of the anterior interosseous division.\nWhile this vessel is passing between the two bones above the ligament, it gives off the recurrent interosseous branch, which, usually of considerable size, perforates the lower part of the supinator radii brevis to reach the back of the forearm. Subsequently it is directed upwards, lying on this muscle, and beneath the anconeus, until it attains the lower part of the arm, where it terminates by anastomosing with a large branch or branches which proceed from the superior profunda, as it turns round the humerus, and in the substance of the outer head of the triceps. It supplies the muscles between which it is situated, and sends a branch to the articulation of the elbow-joint.\nA very constant branch, though usually only of small size, is the twig from the ulnar artery which accompanies the median nerve, continuing along it through the forearm until gradually lost from increasing minuteness. It is the basis of an important variety which will be mentioned hereafter.\nLow down in the forearm, the ulnar artery gives off a branch which runs along the ulnar side of the metacarpus, and supplies this side of the little finger with a dorsal twig. Accompanied by a branch of the ulnar nerve, it turns backwards from the vessel just above the inferior extremity of the ulna, beneath the flexor carpi ulnaris tendon ; and reaching the inner side of the wrist, continues in a direct line to its termination. It anastomoses with the posterior carpal arch, and, on the metacarpus, with the palmar arch of the ulnar artery.\nThe remaining branches of the ulnar in the forearm are two, the arteri\u0153 carpi ulnares anterior et posterior, which occupy a position closely resembling that of the similar branches from the radial artery on the opposite side of the limb. Each runs transversely outwards on its respective surface of the wrist joint, and unites with the radial branch, and from this union, (which, in the case of the posterior vessels, is a \u201c carpal arch\u201d in size and regularity of arrangement) branches perforate the ligaments to supply the articulations and bones of the carpus. In addition to the\nQ","page":225},{"file":"p0226.txt","language":"en","ocr_en":"226\nRADIAL AND ULNAR ARTERIES.\nopposite vessel, the anterior inosculates with the termination of the anterior interosseous and with small branches sent upwards from the superficial and deep palmar arches: while the arch formed by the posterior joins the posterior interosseous, and the dorsal branch of the anterior interosseous ; and gives off a small branch which occupies each of the two ulnar metacarpal spaces on the back of the hand.\nThe communicans uln\u00e6 is a branch of large size, which passes away from the posterior surface of the ulnar vessel at about the lower border of the annular ligament, and disappears by sinking between the abductor and opponens minimi digiti, to join, deeply in the palm, with the ulnar extremity of the palmaris profunda or palmar arch of the radial, to which it usually approximates in size. It gives small branches to the muscles while passing between them.\nIn the palm of the hand, the digital arteries are the only branches of the vessel which attain any size : there are four of these, the first supplying the ulnar side of the little finger, and the remaining three corresponding each to the opposed sides of two fingers : the most external being between the middle one and the index. They occupy a situation superficial to the nerves and tendons, and continue forwards, each as a single branch, until they reach to the clefts of the fingers ; lying in intervals between the commencing sheaths of the tendons, and limited in front by the transverse ligament of the fingers, and behind by the strong ligament on the heads of the metacarpal bones. In this space lies also the similar digital branch of the median nerve, but beneath the artery, and at its inferior termination, each bifurcates into branches for the neighbouring side of the fingers which bound the cleft. Here the vessels are crossed by the nerves, and in the remainder of their length, are situated along the border of the finger, to its termination, the nerve being anterior. At the extremity of the finger, the branch of each side gives off a twig to the under surface of the nail, and the remainder immediately uniting in an arch with the similar branch of the opposite side, breaks up into a network, whose meshes thus form a highly vascular subtra-tum to the sensitive papillary surface which especially occupies this part. In its course along the finger, beside many smaller branches, each digital artery gives off a transverse branch ]ust above the several phalangeal articulations ; which, by joining with its fellow, forms an arch whence proceed the smaller vessels to the joint.\nVarieties of the radial and ulnar arteries. \u2014 The size of these vessels, together with the comparative exposure to mechanical injury which their situation involves, renders an exact knowledge of their distribution absolutely essential to the surgery of the upper extremity ; and the same causes also require that the more important varieties, which constitute so large a per centage of their actual numbers, should at least experience some\nconsideration. In sketching out a few of these it is impossible to avoid acknowledging great obligations to Mr. Quain\u2019s recent work, \u201c The Anatomy of the Arteries,\u201d in which the number of subjects, which serve as the groundwork of the estimates, the evident care with which they have been examined, and the beauty of the illustrations, leave little to be wished for.\nVarieties of origin. \u2014 Rarely does either of the two vessels arise from the brachial at a point lower than the ordinary situation opposite the coronoid process of the ulna : a higher division of this artery, or as it is called, a \u201c high origin\u201d of one of these its branches, is, on the contrary, by no means an uncommon occurrence, It is worthy of notice, that in the majority of these cases, there is no lateral correspondence of the variety, \u2014 in the opposite limb the distribution is the usual one.\nThe most frequent of the two is the high origin of the radial, which may corne off from the axillary, or from the brachial artery in any part of its course. In this case, the remaining trunk, although directly continuous with the ulnar artery, and lacking the usual means of distinction from it, bears yet the name of brachial, since it generally possesses the ordinary relations and distribution of the latter vessel. Under these circumstances, the radial passes down the arm from the place where it is given off, generally lying rather close to the brachial, and on its outer side, until it reaches the forearm ; subsequently it preserves its usual arrangement and termination. But though, for the most part, its course is thus only altered by the possession of an additional portion in the upper arm, this irregularity is sometimes associated with another which concerns its course, viz., a position of the artery superficial to the fascia ; and here it would often have a close juxtaposition to thejnedian basilic vein at the bend of the elbow, which carelessness in ven\u00e6seetion might render dangerous or even fatal. A similar deviation may obtain in the remainder of its course, placing it superficially to the supinator radii longus, instead of beneath its overlapping inner border; or causing it to cross over the extensor tendons at the wrist instead of under them. The latter variety is frequently associated with another alteration in the course of the vessel, which, after giving off the superficialis vol\u00e6 at a point much higher than usual, immediately turns round the outer border of the forearm, so as to leave this small branch alone occupying its ordinary position at the wrist. Other deviations are comparatively rare: \u2014 thus occasionally the vessel enters the palm in the second instead of the first interosseous space.\nVariations in its distribution appear chiefly dependent on its relative size. If smaller than usual, a kind of enlarged communicans uln\u00e6 reinforces its deep palmar arch, or gives off its radialis indicis and magna pollicis branches : or the compensative stream may arrive by another channel, viz., a dilated anterior interosseous to join the artery as it turns round the wrist; or by a large posterior branch of","page":226},{"file":"p0227.txt","language":"en","ocr_en":"RADIAL AND ULNAR ARTERIES.\n227\nthe same vessel which meets it just before entering the metacarpal interspace. Where, as is by no means infrequent, the radial is larger than ordinary, its increased size is principally expended in supplying, through a large superficialis vol\u00e6 artery*, one or more of the outer digital branches which usually come from the superficial palmar arch: or, by means of a dorsal metacarpal of unusual magnitude, digital branches to the opposed sides of the index and middle fingers.\nThe high origin of the ulnar is contrasted with that of the radial in another respect beside that of its lesser frequency, since it is almost always conjoined with an important difference in the situation of the vessel in the forearm, which lies superficial to the flexors ordinarily covering it, and immediately beneath the fascia: \u2014 sometimes it is even sub-cutaneous. Its course is also somewhat affected by this origin, the vessel approaching the inner side of the forearm at a higher point than usual : in other cases, however, it possesses almost a median position during the greater part of this region, and only turns inwards to its ordinary distribution near the wrist.\nIn size, the ulnar artery is more frequently diminished than increased by variations. The decrease is compensated sometimes by a radial vessel supplying one or more of its digital branches or contributing to its palmar arch : at others, its long branch which accompanies the median nerve is enlarged to a vessel of considerable size, which similarly assists it ; while, in a few instances, the dilated anterior interosseous has an analogous termination.\nThe origin of the interosseous artery is subject to some variation, being liable to occur as a divarication from the radial or brachial, or though rarely \u2014 from the axillary : its enlargement aids a deficient radial or ulnar vessel, just as its diminutive size is supplied by them.\nThe branch with the median nerve enlarged to a \u201c median \u201d artery, has been already mentioned ; it passes under the annular ligament as it enters the hand, and may reinforce the deficient radial or ulnar ; bnt most frequently the latter of the two, by joining the superficial palmar arch.\nFinally, as to the varieties in the hand, the mode in which a diminished superficial palmar arch is obviated, has already been described ; and an unusually small deep arch is compensated by the ulnar communicating, which is generally little inferior in size to the radial contribution. For individually smaller digital branches are substituted enlarged dorsal metacarpal ; and in the case of the magna pollicis the superficial palmar arch, the superficialis vol\u00e6, or the median artery, may either of them make up the deficiency.\nIt may be desirable to attempt a generalization of these special variations; in order to this, let us return for a moment to the ordinary\n* Such a vessel, occupying from a high origin the place of the artery, hut more superficial than it, has on this account been mistaken for a \u201chard\u201d pulse, and the patient depleted accordingly.\nanatomy of the vessels of the forearm and hand considering them as a whole. Such a view assisted somewhat, it must be confessed, by our knowledge of these varieties, would discover in the forearm five longitudinal trunks, all possessing some feature, whether of size, length, or constancy, which especially recommends them to our notice. They are the radial, ulnar, and anterior interosseous vessels, together with the posterior branch of this latter, and the branch with the median nerve. The anastomosis and distribution of the extremities of most of these, forms around the wrist an arterial circle which is much more pronounced posteriorly.* In the hand, two arches which are continuations of the larger vessels occupy its surface of flexion, at different heights and depths ; defended from the pressure inseparable from prehension by a strong fascia, whose protective effect is aided during flexion by a tightening muscle. They join by anastomosis with the extremities of the longitudinal vessels, or the imperfect anterior carpal arch. Three branches run lengthwise in most of the metacarpal interspaces ; one on the dorsum from the posterior part of the carpal circlet, two at different depths in the palm from these arches ; the dorsal and deeper palmar uniting at the superior extremities of those intervals, and all three inosculating at their inferior terminations near the clefts of the fingers.\nAll the varieties above mentioned would be referrible to the increased development either of one of these longitudinal branches, or of some portion of this complete and large anastomosis. The several varieties are, in fact, an exaggeration by turns of a different vessel ; which in its course towards distribution may return its contents to the ordinary channel by any one of these series of inosculations ; whether it be the superficial or deep arch, the posterior carpal arch, or finally, the superior or inferior extremity of the aforesaid interosseous spaces.\nThus from these vessels alone might be deduced the law, of which the origin of the obturator from the epigastric, or the sublingual from the facial, are familiar and important instances; viz. that varieties of arteries occur as the exaggerations of an ordinary anastomosis j- : while it is no less evident that the deviations are compensative in the strictest sense ; i. e. that the amount of blood entering the limb is no ways affected, for that an in-\n* Unless we considered the deep palmar arch as the anterior half of the carpal ring, a view which the comparative infrequency of the minute \u201c anterior carpal arch \u201d would almost allow of.\nf It may be urged against such a generalization, \u201c that it would scarcely include the varieties of those vessels which immediately spring from the heart or aorta: since anatomy shows the amount of their ordinary anastomosis, and the number, size, and regularity of the vessels effecting it, to be utterly disproportionate to the magnitude of these variations.\u201d But a reference to the aorta and branchial arches, from which they are developed in the foetus, would again include them in the category of dilated inosculations.\nG 2","page":227},{"file":"p0228.txt","language":"en","ocr_en":"RADIO-ULNAR ARTICULATIONS.\n228\ncrease of one is a diminution of some other vessel \u2014 or vice versa.\nThe directness of these inosculations, and the frequency of these resulting irregularities together exert an important influence on surgical practice, which may be regarded in three points of view. Firstly, it necessitates unusual care in the ordinary operations ; since we may open an artery of dangerous size, where we least expect it. Secondly, it renders operations undertaken on the vessels themselves liable to immediate non-success ; for we may find only a twig where we expect an artery of influential magnitude. Thirdly, it may also cause their mediate failure ; the width and number of the anastomosing channels rendering deligation of a trunk useless, by filling it in a very short space of time below the ligature. Fortunately, however, the same position that renders them more liable to injury affords somewhat of a substitute for the operation by also exposing them more directly to external pressure.\nThe diseases and injuries of the radial and ulnar artenes scarcely offer peculiarities sufficient to demand a special notice.\nAneurism as the result of disease, an extremely rare occurrence in the brachial artery, would appear to be here still more infrequent ; and this remarkable immunity as compared with the lower extremity has been differently ascribed to a supposed greater vitality of the vessels nearer the heart, or with better reason to the less exposure of the arm to strains or shocks. Even this explanation, however, has so much imperfection about it, that it seems better to avoid theorising on the subject until more is known both of the physical re.ations of the different tubes to their central engine, and of the differences in the nature and rapidity of the nutrition of their coats, which may be presumed to exist.\nFalse aneurism may occur in any part of their course as the result of puncture or incision of their coats; the sac of the tumour being formed by the nearest investing fascia, and lined by the areolar tissue of the neighbourhood condensed by the pressure of the contents. These consist of blood, which is usually in considerable quantities, and has experienced more or less coagulation subsequently to its discharge from the opening of the artery which occupies some part of the inner surface of the cavity. But neither in these points, nor in the treatment usually adopted is there anything which requires particular specification.\nThe disease of the arterial system generally, which constitutes so frequent and important a part of the series of changes included in the term \u201c old age,\u201d of course includes these vessels. Ossification of the radial artery is by no means rare, although in this extremity it is very unusual to find it occluding the tubes or leading to senile gangrene. Here, from the superficial position of this vessel, it is often a valuable index by which an insight is afforded into the condition of other and more important arteries. In this latter stage of the change the vessel is rather larger than normal, very hard,\nthick, and tortuous : while the impulse of the heart communicated to it by its contents, and tending to efface these abnormal curves, often almost lifts it from its situation at each stroke. In an earlier stage of the affection it is much less easily recognised, but even here the tactus eruditus maj' sometimes appreciate the change ; and though it is perhaps difficult to translate the sensation into words, such a pulse might be paradoxically described as being at the same time hard to the touch, and comparatively soft and yielding to the pressure, while its beats are associated with unusually little expansion, though they strike the fingers with more force.\n( William Brinton).\nRADIO-ULNAR ARTICULATIONS. {Articulations radio-ulnaires\u2014Verbindungen des Ellenbogenbeins mit der Speiche.)\u2014Wherever the anterior extremity is modified to serve as an instrument of prehension, one chief part of the provision for greater freedom and facility of movement occurs as the correlative modification, not only of the two bones of the forearm, but also of the articulations which mutually connect them at their upper and lower extremities. In man, in whom the arm, losing its locomotive, attains its most complete prehensile development, the radius enjoys a very considerable degree of motion around the ulna by means of these joints. And by the alternate preponderance of either of the two bones in the wrist and elbow joints which are situated at their opposite extremities, this mobility of the radius is increased, while the freedom of movement predicable of it becomes extended to the hand which occupies its distal termination : and thus the rotatory movement which is gradually superadded to the ordinary flexion and extension of the limb finally reaches its maximum.\nIn each of these articulations we shall separately describe, 1. Its anatomical constituents\u2014the several structures which serve to allow of, or to limit, motion. 2. The result of their functions\u2014the movements of the joint.\n(1.) The upper radio-ulnar articidation\u2014 whose elements are the head of the radius, the lesser sigmoid cavity of the ulna, the annular ligament, and a synovial membrane.\nThe round head of the radius \u2014 represents in shape the upper part of a cylinder, or rather a horizontal segment of an inverted cone, which becomes continuous below with the shaft of the bone by means of a constricted neck. It thus offers two articular surfaces : one, a shallow cup-shaped cavity which plays on the radial tuberosity of the humerus : another, the side of the cylinder, which has a linear measurement of about a quarter of an inch at its deepest part, where it corresponds to the lesser sigmoid cavity of the ulna and ends below in a prominent margin ; elsewhere it is narrower ; and subsides more gradually into the neck of the bone. These two smooth surfaces merge into each other at the angle where the base and circumference of the cylinder meet,","page":228},{"file":"p0229.txt","language":"en","ocr_en":"RADIO-ULNAR\nbut it is to the latter only that our attention is at present directed.\nThe sigmoid cavity of the ulna\u2014 is a depression situated on the outer side of its upper extremity, and, in respect of its position, it might be expressed as an articular facet seated on the external margin of the coronoid process. In shape it is somewhat quadrilateral ; and is concave in both directions, but most so in the anterio-posterior, which corresponds to the convexity of the head of the radius, and is also much the longest surface of the two. With trifling individual variations, it usually forms about the fourth of a circle. Superiorly, it is separated from the greater sigmoid cavity by a smooth elevation directed from before backwards : anteriorly, inferiorly, and posteriorly, the border of this articular surface overhangs the coronoid process of the ulna, the concave upper part of its anterior surface, and its posterior surface respectively. The junction of the two latter sides of its margin is marked by a strong ridge, which commences the external border of the bone : and, frequently the antero-inferior angle gives off a similar prominence ; which, after a short course downwards, converges to join the preceding.\nArticular cartilage covers these surfaces of the radius and ulna.\nThe annular or orbicular ligament \u2014 is the next constituent, and is a strong and somewhat cord-like band of white fibrous tissue, which completes the remaining three-fourths of the articular circle left unaccounted for by bone. Its width is about one third ot an inch, its direction is horizontal like that of the sigmoid cavity. It arises behind from the posterior margin of this surface, and partly from its inferior border, uniting beyond these with the periosteum covering the surfaces of bone overhung by them. In front, it is inserted into the anterior margin in a similar manner. Above, it receives and is continuous with the anterior ligament of the elbow joint ; farther outward, it is also joined by the external lateral ligament of the same articulation. Its lower border is free around the neck of the radius.\nThe synovial membrane is a process sent off from that which lines the articular surfaces of the elbow joint. A cul-de-sac passes downwards into the lesser sigmoid cavity, extending to its inferior extremity, but around the neck of the radius, and between it and the orbicular ligament, the remainder of this circular pouch has a diminished vertical extent ; sufficient, however, to allow it to pass under the orbicular ligament, and appear from beneath its lower border.\nThe movement of the head of the radius at this articulation is one of simple rotation around its own axis ; since the articular surfaces in contact with it together form a circle, in which its only movement can be a revolution. And, as above stated, about three-fourths of this circle is formed by ligament; the remainder by bone. But in addition to this chief provision for the limitation and di-\nARTICUL ATION S.\t229\nrection of motion, the convex radial tuberosity of the humerus forms a kind of pivot, which is received into the cavity which occupies the upper surface of the radius, and, no doubt, steadies and assists the movement by tending still more to define the axis of this part of the bone. The articulation of the atlas with the odontoid process of the axis, offers many analogies to this of the radius and ulna both in the structure of the joint and in the resulting movements.\n(2.) The lower radio-ulnar articulation\u2014 is, in many respects, the reverse of the preceding ; since instead of presenting a cylindrical extremity of the radius revolving within a concave facet of the ulna, the latter bone itself offers a rounded termination, on and around the outer side of which the radius plays by a concave articular surface. The constituents of the joint are, the surfaces of the radius and ulna just alluded to ; a fibro-cartilage which, with a kind of imperfect ligamentous capsule, forms the means of union of the bones ; and a synovial membrane interposed between their articular surfaces.\nThe loiver extremity of the radius \u2014 ap proaches somewhat to the form called by geometricians a parallelopiped. Its largest surfaces are the anterior and the posterior : the upper is joined and surmounted by the shaft of the bone, and the lower enters into the formation of the wrist joint. The outer side is occupied by the tendons of the muscles which extend the thumb : and the inner, which looks slightly upwards, articulates with the ulna.\nThis surface is quadrilateral, and of these the two antero-posterior sides are much the longest. The upper is nearly straight, the lower somewhat concave downwards to adapt it to the convex surface of the radio-carpal articulation ; and they slightly diverge behind so as to make the posterior vertical border almost twice as deep as the corresponding anterior side. The articular surface itself is concave from before backwards, taking a curve whose extent is about one fifth of a circle.\nThe lower end or head of the ulna \u2014 is of even smaller size than the upper extremity of the radius which was previously described ; a condition which is in conformity with its slight share in the wrist joint. The base of this cylindrical head has a smooth surface and is almost circular in shape ; internally it offers a depression bounded by the prominent styloid process extending vertically downwards; externally, a margin defines its separation from the articular facet which occupies the outer part of the cylinder.\nThis convex surface is usually a little longer in the horizontal direction than the corresponding radial concavity, forming about a fourth of a circle ; but in all other respects it is, as it were, moulded to it. Above, its margin projects beyond the constricted shaft. A layer of articular cartilage covers both these surfaces. Ligamentous fibres in sparing quantities, and with no very definite direction, unite the upper, anterior, and posterior bordei s","page":229},{"file":"p0230.txt","language":"en","ocr_en":"RADIO-ULNAR ARTICULATIONS.\n230\nof these articular facets so as to result in a species of capsule.\n_ The triangularfibro-cartilage is brought into view by removing the preceding ligament after laying open the wrist joint, and separating the two bones. Arising by a broad base from the sharp margin which separates the ulnar and carpal articulating surfaces of the radius, it passes inwards beneath the head of the ulna with continually diminishing width, until finally its apex is inserted into the base of the styloid process of this bone. At the commencement of this course it is nearly fiat, though rather thicker at the margins than towards the middle ; indeed, it is by no means unusual to find a \u201c perforation \u201d or deficiency in this part\u2014but towards its apex its thickness is so much increased as to give it almost a cord-like form where it joins the ulna. It belongs to the class of fibro-cartilages, and like most of these, the proportions in which its component tissues are mixed vary greatly in different parts: thus the centre consists chiefly of cartilage, while towards its periphery it is almost purely ligamentous. Its lower surface is covered by the synovial membrane of the carpal articulation, and is in contact with the upper surface of the cuneiform bone. Above, it corresponds to the lower extremity of the ulna, and the structure itself is the medium by which that bone takes its limited share in the wrist joint. Its borders, looking forwards and backwards, are united with the anterior and posterior ligaments of this articulation.\nThe synovial membrane, \u201c sacciformis,\u201d as it is usually called, is large and loose, and is not only interposed between the radial and ulnar surfaces, but is also continued inwards beneath the extremity of the ulna, so as to cover it and the contiguous upper surface of the triangular fibro-cartilage. In passing from one of these apposed surfaces to the other, it lines, for a very short distance, the capsule and the two ligaments of the wrist joint which unite them.\nThe movement of the lower end of the radius may easily be deduced from the above description, where the shape of the articular surfaces and the attachments of the fibro-cartilage alike indicate a rotatory movement of this bone around the ulna ; since there is an almost complete correspondence between the apex of the ligament and the centre of that circle of which these articular surfaces would form a part.\nBut although the motion at either of these articulations is thus no very difficult deduction from their anatomy, the mutual consistency of the two, or the movement of the radius as a whole, seems to have been much less understood. The somewhat obscure language in which this has been described would allow us to imagine that a kind of rotation of this bone on its axis was supposed to result as the balance of the movements which obtain at the several joints. These anomalies and inconsistencies have been cleared up by Mr. Ward, in his very able work on Osteology;\nin which he points out that the axes of the head and neck of the radius above, and that of the head of the ulna below (the evident centres of rotation in each case) are continuations of each other, and form different portions of one and the same line, which is thus the real axis of the whole bone in its motions. In other words, the axis of the head and neck of the radius, prolonged downwards, would fall upon a point in the lower surface of the ulna, the centre of the circle whereof the sigmoid cavity is a part. And this, he urges, will alone explain how the partial rotation of the bone is altogether independent of any antero-posterior movement of its head, and occurs \u201c without disturbance to the parallelism of the superior joint.\u201d\nThus we might imagine the articulations of the forearm to be the immediate consequence of two chief necessities of movement ; one of flexion and extension of this segment of the limb, another of alteration of aspect of the terminal segment or hand ; the latter can scarcely be accomplished in any other way than by semirotation. The conditions of powerful flexion and extension are, on the contrary, best suited by a more or less gingly-moid joint at each extremity; and the shape of the interlocking surfaces which forms the chief security of such an articulation, would render it insusceptible of this partial rotation. These requirements, incompatible of fulfilment by one bone, are met by the addition of another, to which the hand is attached. And now a new necessity arises ; for the superadded lever must be associated with the pillar previously existing, so far as regards the first movement, but dissevered from it as regards the second. This is accomplished by giving the radius a very limited participation in the elbow joint, a very considerable one in the wrist; and by making the ulna supply the terminal fixatures of the rotating shaft. The peripheral and com-plete condition of the upper attachment, the internal or centric and incomplete state of the lower, which, like the shaft itself, is here reduced to a part of a circle ; these are provisions which, like many met with in other parts of the body, at once economise means and preserve the symmetry of the limb.\nPronation and swpination. \u2014 The extremes of this rotation of the lower extremity of the radius constitute the states of pronation and supination. So far as these result from the movements of this bone, they are not quite opposite aspects of its surfaces, or of those of the hand, since the angles which they mutually form in these conditions are scarcely equal to a quadrant and a half, or 135 degrees. And this fact, which the appearance of the articular surfaces alone would lead us to suspect, may be reduced to a certainty by the very simple experiment of bending the forearm, and then from extreme supination pronating the wrist, and comparing the lines formed by its anterior surface in both these positions with each other, so as to take the angle through which the surface has passed. Or better still, since it removes all suspicion of interference with the","page":230},{"file":"p0231.txt","language":"en","ocr_en":"REN.\t231\nmuscles that effect pronation, fix the condyles of\u2019 the humerus by any means, and then repeat the examination of these angles.\nPronation and supination may, however, be carried far beyond this limit of the radial motion ; aided by powerful rotation of the humerus inwards and outwards respective^, the surfaces will attain to complete opposition of direction, or 180 degrees of intervening angle, and even to a variable distance beyond this which is, on an average, almost another quadrant.\nIt deserves also to be noticed, that these movements are often converted into rotation around the axis of the lower part of the forearm and wrist, by a somewhat similar humeral movement. For example, simultaneously with pronation, the lower end of the humerus is carried outwards and upwards, and a similar deviation is thus impressed on the ulna articulated with it, which extending to its lower extremity, results in the rotation of this part of the limb ,* i. e. in the completion of pronation, without the usual advance of the inner border of the forearm towards the median line of the body.\nDislocations of these joints. \u2014 At the upper of the two radio-ulnar articulations either bone may be thrown out of its place in several directions. Displacements of the ulna, however, chiefly affecting the elbow joint into which it so largely enters, are included amongst those of this part ; and though those of the radius are, both in nature and effects, accidents of the radio-ulnar articulation,_ in practice it is very difficult to avoid considering together injuries which have so close a relation, albeit, strictly speaking, an accidental one. Hence the reader is referred for these to the article \u201c Abnormal Conditions of the Elbow-joint.\u201d\nAt the lower joint the radius and ulna may be displaced from each other by external force, or by the violent action of the muscles in extreme pronation or supination : but the latter is a very rare occurrence. Looking to this articulation only, it might be difficult to define which bone was dislocated : whether, for instance, the ulna was \u201c dislocated backwards,\u201d or the radius \u201c dislocated forwards,\u201d since, in such a case, either of these phrases would equally express their altered relation to each other. It is most convenient to consider this question determined by the condition of the neighbouring wrist joint, and to instance those cases as dislocations of the radius where the extremity of this bone is located unnaturally forwards or backwards, both as regards the carpus and head of the ulna. And, similarly, where the wrist and radius preserve their ordinary relation, but the lower end of the ulna is displaced with respect to both ; here it will be better to consider the ulna as. the luxated bone, even though the accidents might sometimes resemble each other in their causes as well as mode of production.\nThe dislocation of the radius forwards is easily recognized by the styloid process of this bone and the trapezium no longer lying\nin the same vertical line ,* and by the situation of the extremity of the radius in front of the bones of the carpus, causing an unnatural prominence there. The luxation backwards would appear to be almost unknown, a reversal of these signs would indicate it. In both, the relative position of the ulna and wrist is little affected.\nIn the dislocation of the ulna, the ordinary connection of the hand and radius being kept up, the pronation or supination of the limb becomes a feature of a very striking kind. The signs of the luxation backwards are extreme pronation, the head of the ulna projecting beneath the skin at the back of the forearm, and the styloid process of this bone occupying a line posterior to the border of the wrist or the cuneiform bone. The dislocation forwards is of extreme rarity, but the above marks, mutatis mutandis, would leave little room for doubt as to the nature of the accident.\nThe diseases of these articulations offer no peculiarities which deserve a separate description.\n(William Br inton.)\nREN* \u2014 THE KIDNEY (Gr. vecppog ; Germ. Niere; Fr. Rein; It. Ren). \u2014 The kidney is a double gland, having for its office the secretion of a liquid which in common language is called urine. Since the time of Malpighi, the structure of this organ has excited in a more than ordinary degree the interest of the anatomist and the physiologist ; but this interest has been much increased by the researches of Mr. Bowman, whose admirable paper on the \u201c Structure and Use of the Malpighian bodies of the Kidney f,\u201d while it has placed the kidney in the list of those organs whose anatomy is most clearly demonstrated, has acquired for its author a reputation which will endure so long as anatomical science is cultivated.\nThis article is divided into three parts ; the first part, containing a brief account of the general form and structure of the renal organs in the lower animals, as introductory to the second part, which contains an account of the anatomy and physiology of the human kidney, with references to such facts in the minute structure of the kidneys of some of the lower animals as will serve to throw light upon the structure and office of the organ in man. The third part contains an outline of the pathology of the kidney.\n* In explanation of the use of the Latin word Ren as the heading of this article, the Editor deems it necessary to state, that the article was undertaken some years ago by a gentleman who failed to complete his engagement in time for its publication under the title Kidney ; it was found necessary, consequently, to postpone the subject, and to adopt the present title. The article was subsequently committed to other hands, in which it shared a similar fate to that which it experienced at first, and it ultimately fell into the hands of its present able author. \u2014 Ed.\nj- Philosophical Transactions, 1842.\nq 4","page":231},{"file":"p0232.txt","language":"en","ocr_en":"232\nREN.\nPART I.\nRENAL ORGANS IN THE LOWER ANIMALS.\nUnder this head we purpose to refer briefly to such facts in the anatomy of the urinary organs of the lower animals as will serve to render more intelligible the structure and office of the human kidney.\nInvertebrata. \u2014 That the excretion of urine is a function of great importance is sufficiently manifested by the fact that a special organ for the performance of this office is found in animals very low in the scale of organization.\nIn insects the urinary glands are usually in the form of long and delicate tubes, but sometimes present the structure of groups of round vesicles, as in the Carabus, in which the common duct terminates in a small dilatation ; the urinary bladder is likewise present in the water-beetles. The excretion is poured into the termination of the intestine, or evacuated contiguous to the anus.*\nIn the Arachnida, \u201c two long and slender urinary tubes communicate with the beginning of the c\u00e6cum, which seems to stand to them in the relation of an urinary bladder,\u201d\nIn the Lamellibranchiata, \u201c the returning veins of the body form a remarkable plexus at the base of the gills near the pericardium, which assumes the form of a distinct glandular organ in the higher Bivalves. The secretion of this venous body abounds with calcareous particles, and the gland was called by Poli the secreting organ of the shell. Modern analysis has detected a large proportion of uric acid in the peritoneal compartment enclosing this venous plexus, and has thus determined it to be the renal organ.\u201d f\nIn the Gasteropoda, the urinary gland is a follicular organ attached to the walls of the branchial cavity. In some species of Palu-dina the duct dilates to form a small receptacle.\nAmong the Cephalopoda, the Nautilus presents the supposed analogues of the urinary organs in the form of clusters of glandular follicles of a simple pyriform figure, three clusters of such glands contained in membranous follicles being situated on each of the four branchial veins. The walls of the receptacles exhibit in some parts a fibrous texture, apparently for the purpose of compressing the follicles and discharging their secretion into the branchial cavity by apertures at the base of the gills. The analogues of these organs exist in the higher Cephalopoda, in which they are considered to act as kidneys by Mayer; and Prof. Owen remarksJ, \u201cit is more philosophical to conclude that the organs of so important an excretion should be present in all the class, than that they should be represented by the ink-gland and bag, which are peculiar to one order.\u201d\nVertebrata. \u2014 In Fishes the kidneys are\n* Professor Owen\u2019s Lectures on Comparative Anatomy.\nf Ibid.\nj Lectures on Comparative Anatomy.\nlong and narrow ; they are situated on each side of the mesial line, immediately beneath the bodies of the vertebrae, and extending through the whole or the greater part of the dorsal region of the abdomen. They are usually broadest and thickest anteriorly, while they become smaller and approach each other as they extend backwards. Sometimes a single common ureter quits the coalesced hinder ends of the kidneys. In some species the kidneys are thickest at their posterior ends. They have not a well-defined capsule, but their ventral surface is immediately covered by an aponeurotic membrane, against which the peritoneum and the air-bladder, when present, are applied. The renal tissue presents a uniform appearance without division into a cortical and medullary portion. The urinary tubules pass immediately into the ureter without the intervention of a pelvic cavity. Malpighian bodies exist in the kidneys of the fish as in those of the higher vertebrata ; the structure of these bodies will be fully explained in a subsequent part of this article. The kidneys are supplied throughout their entire length by numerous small branches from the abdominal aorta. In addition to the arterial blood thus supplied to the kidneys, these organs also receive a large quantity of blood from the veins which proceed from the posterior part of the body. This peculiar system of veins, which was discovered by Bo-janus, and more fully described by Dr. Ludovic Jacobson*, is found in birds and reptiles as well as in fishes. In its primary form it undergoes, according to Jacobson, three degrees of modification. The first modification exhibits the following form : \u2014 From the skin and muscles of the middle part of the body branches arise, which form several trunks, passing separately to the kidneys.\nIn the second modification, the veins which return from the posterior part of the body are received into this separate system. The caudal vein, which brings back the blood from the skin and muscles of the posterior part of the body, divides into two branches, which, having received some veins returning from the middle part of the body, pass to the kidneys of each side, and distribute their branches in the substance of these glands.\nIn the third modification, the veins of this system are formed in the same manner as in the preceding, excepting that the caudal, or other vein returning from the posterior part of the body, gives off a branch to the vena port\u0153.\nThe blood, returning from the middle and posterior part of the body in the first and second modification of this system, is conveyed only to the kidneys ; but in the third it is divided between the kidneys and the liver. The inferior vena cava of the common venous system, in the second and third modification is composed of the veins returning from the kidneys and testicles or ovaries. In the first modification, the caudal vein receives the veins returning from the kidneys, is united\n* Edinburgh Medical and Surgical Journal, vol. xix.","page":232},{"file":"p0233.txt","language":"en","ocr_en":"233\nREN.\nwith the veins of the testicles or ovaries, and in this manner forms the inferior vena cava.\nThe above is a general description of this peculiar system of veins. With reference to its existence in fishes, it will suffice to add, that in different genera this venous system appears in all its modifications.\nIn Reptiles, the kidneys are generally situated very far back, even within the cavity of the pelvis, where a sacrum exists, as in the Chelonian and Saurian orders ; and in these tribes they are very partially covered by the peritoneum being firmly imbedded in the sacral region. But in serpents, in consequence of the elongated form of the body, and the complete flexibility of every portion of the spine, the kidneys are peculiar both in their position and general structure. The kidneys of an Ophidian are not placed upon the same level, but the right is situated much more anteriorly than the left ; a circumstance which much facilitates the packing of the abdominal viscera, and contributes greatly to ensure the free movements of the vertebral column at this place. For the same reason the kidneys of a serpent are divided into numerous lobes of a compressed reniform shape, placed in a longitudinal series upon the external surface of the ureter, and loosely connected to each other and to the spine by cellular tissue and a fold of the peritoneum.* The kidneys of reptiles, like those of fishes, have no distinction of cortical and medullary substance ; and the urinary tubules pass immediately from the substance of the kidney into the ureter.\nThe peculiar venous system described by Prof. Jacobson is found in reptiles under the form of the third modification ; that namely, in which the blood returned by the veins from the back and the posterior part of the body, is divided between the kidneys and the vena portae. The exact distribution of these veins in the substance of the kidney of the Boa has been clearly demonstrated by Mr. Bowman, as will be shown, when we come to speak of the minute anatomy of the kidney. The arterial branches, which are comparatively of small size, are derived from the abdominal aorta.\nIn Birds the kidneys are elongated in form, commencing immediately below the lungs, and extending symmetrically on each side of the spine, as far as the termination of the rectum. The posterior surface is moulded into the cavities formed by the bones on which it rests. The ureter proceeds from the anterior aspect, the secreting tubules passing immediately, as in fishes and reptiles, into the ureter, so that there is no pelvic cavity in the organ, nor any division into cortical and medullary substance. The outward form of the kidney is very various, and the surface is divided in different species into a variable number of lobes. Each kidney is invested by a delicate capsule, which extends into the substance of the gland between its lobular divisions. Their texture is much more friable than in mammalia, readily\n* Professor Rymer Jones\u2019s Animal Kingdom.\nyielding under the pressure of the finger, to which they give a granular sensation as their substance is torn asunder.*\nThe peculiar venous system already referred to is described by Jacobson as existing in birds under the form of the third modification. But the arrangement of the veins differs from that observed in reptiles in this respect, that the crural vein after giving off a superior branch to the superior lobe of the kidney, and an inferior to the ischiatic vein, sends a middle branch direct to the vena cava. All the blood, therefore, which in birds returns from the posterior part of the body, is carried partly to the kidneys, partly to the portal vein, and partly, but in small quantity, is conveyed in a direct manner to the vena cava. There are no regular emulgent arteries in birds, the kidneys deriving their arterial blood from various branches of the abdominal aorta.\nThe kidneys of Mammalia present one character which is common to the whole tribe, and by which they are distinguished from the other classes of vertebrata. The character alluded to consists in a division of the substance of the gland into two portions, a cortical and a medullary, the former being the secreting part and containing, as will be more fully shown hereafter, tubes which are very tortuous, while in the latter the tubes are straight, forming minute excretory ducts, through which the secreted products are conveyed into the ureter.\nIn many genera the kidneys are composed of a number of separate lobules or renules, (Jig. 142, a a a), each lobe consisting of a coring. 142.\nPortion of the kidney of a porpoise.\nVide article Aves by Professor Owen.","page":233},{"file":"p0234.txt","language":"en","ocr_en":"234\nREN.\ntical (b) and a medullary substance (e),the latter terminating in a mamillary process (d) which is received into an infundibular offset from the ureter. All the lobules are thus connected with the ureter, forming a clustered mass like a bunch of grapes. The entire kidney is invested by a cellular capsule (e), a deep layer of which (f) passes into the fissures between the lobules, and in the substance of this interlobular tissue the vessels are imbedded. There is no anastomosis between the blood-vessels of neighbouring lobules, as shown by the circumstance that when the artery in any of them has been obstructed in an injected preparation they remain uninjected.* This form of kidney is observed in amphibious Carnivora, as the otter and the seal tribes ; it is also found in the bear, and still more remarkably in the cetaceans. The lobular division of the kidney, which in these animals is a persistent condition, exists in the embryo of all the mammalia. In process of development in the greater number of genera, the lobules coalesce, and thus form a solid glandular organ having a smooth con-tinuous surface, and presenting in the normal state no trace of the original lobular divisions. The kidney of the ox presents a condition intermediate between the lobulated kidney and the solid organ of man and most other mam-miferous genera. In this animal the medullary portion of the kidney has coalesced, while the cortical part is marked out by deep interlobular fissures. The coalescence of the lobules appears to have been arrested at a certain period of its progress. The manner in which the tubes open into the pelvis of the solid kidney admits of some variety. In some genera they open on a continuous concave surface, as in the horse and ass ; in others on a continuous ridge, as in the dog. A more common termination is in a conical projection, the apex of which is received into a calyciform cavity in the pelvis of the kidney. In some genera, as in the human subject, there are several of these conical processes in each kidney ; while in other animals, all the tubes of the gland converge to a single cone, as in the lion, the racoon, the kangaroo, the monkey, the squirrel, &c.\nThe renal artery, derived from the abdominal aorta, enters the hilum of the kidney. The veins generally follow the arteries, but there are exceptions to this rule. In the lion kind the cat kind, as also in the hyaena and in the seal, perhaps one half of the veins yet on the external surface, over which they pass, enclosed in a doubling of the capsule, and so join the trunks from the inside just as the latter are passing out from the hilum. j*\nPART II.---THE HUMAN KIDNEY.\nWe now proceed to give a detailed account of the anatomy of the human kidney, with such facts in the minute structure of the gland in certain of the lower animals as serve to\n* This is seen in the kidney of a walruss, No. 1265 in the Museum of the College of Surgeons.\n\u2022j- Hunterian Museum and Catalogue.\nthrow light upon the structure and office of this important organ in man.\nForm.\u2014The form of the kidney being so familiar as to serve for a standard of comparison with other objects, it appears needless to speak of its resemblance to a French bean, the concave margin being directed towards the spine, while the convex margin, which is thick and rounded, is directed outwards. The upper extremity is usually broader and thicker than the lower. The anterior surface is convex ; the posterior is flatter and rests upon the muscles and fascia. The two kidneys are occasionally, but very rarely, united by a band of renal substance, extending transversely across the spine in front of the aorta. The two glands thus united have the form of a horse-shoe, the concavity of which is directed upwards.\nDimensions and 'weight.\u2014The average length of the kidney is from 4 inches to 4\u00a3 inches, its breadth 2 inches, and its thickness 1 inch. Its usual weight is from 3 to 4 ounces.\nPosition and relations.\u2014The kidneys are situated deeply in the lumbar region on each side of the spine, occupying a space corresponding to the last dorsal and the two or three upper lumbar vertebr\u00e6. The right is usually somewhat lower than the left, being depressed, as it were, by the liver, which is placed just above it. Occasionally one or both kidneys may be found very much out of the natural position, being situated either in front of the spine, or much below the usual position, even as low as the cavity of the pelvis. The kidneys are placed somewhat obliquely, the upper extremities being inclined towards the spine and approaching nearer to each other than the lower. They are imbedded in a layer of adipose tissue, the quantity of which is very variable, being thick and abundant in fat subjects, while in those who have died much emaciated, the loose investment of reticular tissue presents scarcely a trace of fat.\nThe anterior surface of each kidney looks somewhat outwards ; it is partly covered by the peritoneum, chiefly at the upper extremity, and more on the right side than on the left. The right kidney is covered by the ascending colon, and the left by the descending colon. The anterior surface of the right kidney is also in contact with a small portion of the duodenum, and is covered by the right lobe of the liver. In some instances the gallbladder covers a large part of the anterior surface of the right kidney. The left kidney at its upper part lies in contact with the spleen, and is covered by the great end of the stomach when this viscus is distended.\nWith reference to diagnosis, it is important to bear in mind the proximity of the kidneys to the colon, and the possibility of disease extending from one organ to the other. Abscess of the kidney has in many instances been known to burst into the colon, and it is not improbable that ulceration of the colon, either simple or malignant, might extend backwards into the kidney.","page":234},{"file":"p0235.txt","language":"en","ocr_en":"REN.\n235\nThe posterior surface of the kidney looks somewhat inwards ; it rests upon the quad-ratus lumborum muscle, from which it is separated by the anterior division of the tendon of the transversalis ; it is also in contact with the diaphragm, which separates it from the two or three last ribs, and with the psoas muscle, which separates it from the spine.\nFrom a consideration of these relations, it will be seen that exploration of the kidney, with a view to detect enlargement or tenderness, may best be made in the lumbar region on either side. It will also be evident that abscess originating in the kidney may extend backwards, and become diffused amongst the muscles in this region, or that it may approach the surface, and discharge itself by an opening in the loins. Cases of this kind are known to occur ; and when renal calculi have been the exciting cause of the suppuration, these have escaped through the same opening in the lumbar region.\nThe circumference of the kidney presents, 1st, an external border, thick, convex, semielliptical, and directed outwards, backwards, and upwards ; 2nd, an internal border, directed inwards, forwards, and downwards, and presenting about its middle a deep notch or fissure, the hilum, as it is sometimes called. This notch is more marked posteriorly, where it corresponds to the commencement of the ureter and the pelvis of the kidney, than anteriorly, where it corresponds to the renal vein. The notch usually contains some adipose tissue, which passes in with the bloodvessels, and occupies the space between the substance of the kidney and the pelvis.\nOf the extremities of the kidney, the superior, as before stated, is larger than the inferior, and directed somewhat inwards. It is immediately covered by the supra-renal capsule. The liver is above the right, and the spleen above the left. The inferior extremity of the kidney is directed somewhat outwards, and has below it, but at some distance from it, the crest of the ilium.\nThe ureter, or excretory duct of the kidney, extends from the hilum of this organ to the base of the bladder. It is a cylindrical canal, with whitish, elastic walls, varying in size from that of a crow-quill to that of a goose-quill. It is usually dilated at its commencement, narrowed in the middle of its course, and again dilated before its entrance into the bladder.\nIts direction is obliquely downwards and inwards to the sides of the base of the sacrum ; it then passes almost horizontally forwards between the layers of peritoneum forming the posterior ligament of the bladder ; lastly it is directed inwards to the side of the base of the bladder, where it takes an oblique course through the wall of that organ, to open on its inner surface by a narrow orifice in one of the posterior angles of the trigone.\nThe relations of the ureter are the following :\n.\u2014 In the notch of the kidney the ureter lies behind the renal vessels. From the pelvis of the kidney to the base of the sacrum it is in contact with the anterior border of the\npsoas muscle ; it is covered by the peritoneum, and is crossed obliquely by the spermatic vessels. The right ureter has the inferior vena cava on its inner side. On a level with the base of the sacrum, each ureter crosses the common iliac, and below' this the external iliac artery and vein. In the pelvis the ureter lies in contact with the wall of this cavity, being covered by peritonaeum, and crossing successively the umbilical artery,or its obliterated cord, the obturator vessels, the vas deferens in the male, and the superior and lateral part of the vagina in the female. In that part of its course which is included in the wall of the bladder the ureter is very close upon the neck of the uterus, and is thus liable to become involved in cancerous disease of that organ.* That part of the ureter which lies in contact with the anterior border of the psoas may become affected by disease extending from the substance of the muscle. The pathological museum of King\u2019s College contains a preparation in which an abscess, occupying the substance of the psoas muscle, has opened into the ureter.\nThe ureter has two distinct coats or membranes. 1. An internal mucous membrane, continuous above with the mucous lining of the pelvis of the kidney, and below with that of the bladder. 2. An external fibrous coat, continuous above with the capsule of the kidney and with the pelvis, and below with the muscular coat of the bladder. The minute structure of the coats of the ureter will be described in a subsequent part of this article.\nBlood-vessels of the Kidney.\u2014The emu!gent -j-or renal arteries are the largest branches of the abdominal aorta, from which they proceed at nearly a right angle. Their origin is about half an inch below the superior mesenteric artery, the right being frequently somewhat lower and longer than the left. Each renal artery passes obliquely downwards, backwards, and outwards towards the hilum of the kidney, giving off in its course branches to the suprarenal capsule, to the ureter, and to the surrounding cellular membrane. At the pelvis of the kidney the artery usually lies between the vein and the ureter, the former being in front of, and the latter behind, the artery. In the hilum of the kidney, where the artery is surrounded by reticular and adipose tissue, it breaks up into four or five branches, and these again subdivide into smaller branches, most of which pass in front of the pelvis ot the kidney, while a smaller number pass behind this part ; their course and distribution in the substance of the kidney will be described in connexion with the structure of the gland. The right renal artery is covered at first by the vena cava, and then by its corresponding vein ; the duodenum and pancreas are also in front of it. It crosses the spine and the right psoas muscle. The artery\n* Cruveilhier, Anatomie Descriptive.\n\u2022j- Insulsa theoria, qua urinam vasis secretam ex papillis quasi emulgendo prolici credebatur, ea sic denominandi ausam d\u00e9dit. Schumlansky, de Structura Renum.","page":235},{"file":"p0236.txt","language":"en","ocr_en":"236\nREN.\non the left side is covered by its corresponding vein, and crosses the left psoas muscle.\nThe renal arteries occasionally present some anomalies as to their origin, mode of division, or number. In some instances they arise below the usual situation, from the aorta, or even from the common iliac or hypogastric artery. The two last-mentioned origins are usually associated with an unusual position of the kidney, either in the iliac fossa or in the cavity of the pelvis. Meckel* has observed the two renal arteries arising by a common trunk from the anterior part of the aorta.\nThe artery sometimes divides into two or more branches immediately after its origin, in which case one branch usually leaves the others to enter one of the extremities of the kidney. This irregularity forms an approach to another, which consists in an increase in the number of renal arteries, each kidney receiving two, three, or four branches having a separate origin from the aorta.\nThe emulgent or renal vein commences in the substance of the kidney by numerous minute branches, which unite into four or five trunks, and these again unite to form a single trunk, either in the fissure of the kidney, or at a short distance from this point. The vein passes almost transversely inwards to the vena cava, the right vein being shorter than the left, on account of the position of the vena cava to the right of the spine ; the junction of the right vein with the cava is also somewhat higher than that of the left. The vena cava presents a marked increase of size immediately after receiving the renal veins. Each renal vein is placed in front of the corresponding artery ; the vein on the left side crosses over the aorta. The renal veins receive some small branches from the supra-renal capsule, and from the reticular and adipose tissue surrounding the kidney, and the left renal vein is usually joined by the spermatic of the same side.\nThe lymphatics of the kidney are but little known ; they are said to consist of a superficial and a deep set, the latter being the most abundant ; they pass from the fissure of the kidney to the lymphatic glands which surround the aorta and the vena cava.\nThe nerves of the kidney are very numerous, consisting of several small branches from the lower and outer parts of the semilunar ganglion and solar plexus, joined by the descending branches of the small splanchnic nerve. The renal plexus thus constituted accompanies the artery into the fissure of the kidney. This plexus sends numerous filaments to the spermatic plexus, and hence probably the sympathetic connexion which exists between the testicle and the kidney.\nStructure of the Kidney. \u2014 In order to examine the general structure of the kidney, it is necessary to make a longitudinal section from the convex towards the concave border. On examining the surface of such a section, it\n* Cruveilhier, Anatomie Descriptive.\nwill be seen that the substance of the kidney is composed of two portions, differing from each other in their general appearance and arrangement ; an external cortical, and an internal medullary portion. It will also be seen that the entire organ is invested by a fibrous capsule, which at the hilum becomes continuous with the pelvis of the kidney and with the ureter. It appears desirable to examine the general appearance and structure of these several parts before proceeding to the consideration of the minute anatomy of the kidney.\nThe cortical substance forms a layer about two lines in thickness, which occupies the surface of the kidney, and sends inwards prolongations, from one to three lines in thickness, between the conical divisions of the tubular substance. The colour of the cortical substance is much influenced by the quantity of blood which it contains. It is usually of a lightish red colour, but in anaemic subjects it very frequently presents a yellowish-white appearance, this being the colour of the renal tissue when deprived of blood. The cortical substance is of a softish consistence, readily tearing beneath the pressure of the finger, and\nFig. 143.\nSection from the surface of the kidney to the apex of one of the medullary cones. The plate is introduced partly to show how accurate was Schumlan-sky\u2019s knowledge of the general structure of the organ. c, g, blood-vessels ; h, the artery terminating in a cluster of Malpighian bodies ; q, s, t, straight tubes, with their dichotomous divisions ; o, bundles of these passing towards the surface and then becoming tortuous ; p, section of blood-vessels. (After Schumlansky.')","page":236},{"file":"p0237.txt","language":"en","ocr_en":"REN.\n237\npresenting an irregular granular surface. In an injected specimen there may be seen scattered through the cortical substance, in every part, except near the surface of the organ, numerous minute red granules ; these bodies have been named after the distinguished anatomist who discovered them, the Malpighian bodies of the kidney. The great mass of the cortical substance is made up of secreting tubules, the existence of which was first clearly demonstrated by Ferrein ; hence they have been named the tubes of Ferrein. The course of these tubes is, for the most part, very tortuous; but near the basis of what will presently be described as the pyramids of Malpighi there is an appearance, visible even to the naked eye, of straight lines radiating towards the surface of the kidney ; these lines result from bundles of tubes passing upwards from the pyramids of Malpighi and retaining their straight course until they reach the surface, where they become tortuous, and pass backwards deeply into the cortical substance (fig. 143).\nThe surface of the cortical portion frequently presents an appearance of lobules, somewhat similar to those of the liver. The form of these lobules varies considerabty ; in some instances they are circular, but very commonly they have a pentagonal or hexagonal outline ; they are usually about \u00a3 of an inch in diameter (fig. 144).\nFig. 144.\nPortion of the surface of the kidney, showing the lobulated appearance which results from congestion of the venous radicles. Natural size ; from a specimen prepared by Mr. Bowman.\nThis lobulated appearance of the surface is produced by the venous radicles which are dispersed at nearly equal distances throughout the cortical substance, each receiving the blood, as will presently be shown, from the plexus surrounding the convoluted tubes. These radicles unite in an irregularly arborescent figure, anastomose, and form the several branches of the renal vein. Those on the surface have a tendency to converge towards a central vessel, which then dips into the interior to join the trunks of the renal vein. Thus are formed the stellated vessels, which are often very conspicuous in diseased specimens, when there has been an impeded circulation through the veins of the kidney. Between the arms of these stell\u00e6 the convoluted tubes are visible on the surface (fig. 145). Ferrein supposed each of these lobules to form the base of a pyramid, the apex of the same being at the extremity of a mamillary process, and he believed that such an elongated pyra-\nmid might be traced continuously from one part to the other, the tissues radiating from\nFig. 145.\nPortion of the surface of the human kidney injected by the artery, t, t, tortuous tubes as seen on the surface; p, capillary plexus surrounding the tubes ; e, a branch of one of the stelliform veins. Magnified forty-five diameters. (After Bowman.')\na point in the mamillary process, through the cortical substance, to one of the lobular divisions on the surface. Mr. Bowman\u2019s preparations show that \u201c each lobule contains many tortuous ducts with their capillaries, but the convolutions of any one duct are not confined to a single lobule.\u201d Hence it is manifest that there is no natural division of the renal substance corresponding with the supposed \u201c pyramids of Ferrein,\u201d and there appears no reason for retaining a name which is not expressive of any fact or definite idea.\nThe medullary substance or, as it is sometimes called, the tubular portion, is of a firmer texture and darker red colour than the cortical portion, and presents itself under the form of cones or pyramids, (pyramids of Malpighi,) the bases of which are directed towards the surface of the kidney and continuous with the cortical portions, while the apices, which are called mamillary processes, or papillae, are free and directed towards the cavity of the pelvis. The number of these pyramids has been variously stated by different anatomists ; their number is not constant, but it is usually about twelve or fifteen in each kidney. Some of the pyramids are compound, being formed by the union of two, which have one common mamillary termination. The number of mamillary processes is therefore less, by four or six, than that of the pyramids. The cut surface of each pyramid has a striated appearance, being composed of tubes which subdivide and radiate in passing from the apex towards the base, where they merge into the cortical substance. These tubes are com-","page":237},{"file":"p0238.txt","language":"en","ocr_en":"238\nKEN.\nmonly named the tubes of Bellini, that anatomist having been the first to show their true tubular character ; they are united by a firm network of fibrous tissue in the substance of which there are some large veins, which take, for the most part, a straight course between the tubes. No Malpighian bodies exist in the medullary cones.\nThe capsule of the kidney is a firm, white, fibrous membrane adherent by its external surface to the adipose tissue in which the kidney is imbedded, and connected by its internal face to the entire surface of the kidney. It sends numerous fibrous processes into the cortical substance, and small vessels pass from the substance of the kidney into the fibrous capsule. These connecting bands between the kidney and its capsule are easily torn when the capsule is stripped from the surface of the kidney. At the hilum of the kidney the capsule becomes continuous below with the ureter and above with the fibrous layer of the pelvis ; at the same point the blood-vessels receive an investment from this fibrous membrane, which is continued upwards with them until they finally break up into minute branches about the bases of the pyramids.\nCalyces, Infundibula, and Pelvis.\u2014The calyces are membranous or fibro-mucous cylinders which receive in their upper extremities the apices of the mamillary processes. Where the membrane is reflected over the apices ol the cones, it is perforated by numerous orifices of the tubes of Bellini, from which a liquid may be seen to escape when pressure is applied to the cones. The calyces are less numerous than the mamillary processes, two or three mamillary processes being occasionally received into one calyx. Tue calyces unite into three small tubes, one corresponding with each extremity and one with the central portion of the kidney ; these have somewhat of a funnel shape, and are called infundibula. The infundibula soon unite to form the pelvis of the kidney, which is a membranous reservoir of a flattened oval figure, terminating below in the ureter. The pelvisand infundibula are usually surrounded by loose reticular and adipose tissue. The blood-vessels of the kidney are placed in front of these parts. The fibrous and mucous coats of the ureter are continuous with those of the pelvis, infundibula, and calyces.\nBefore passing on to the description of the minute structure of the kidney, it is desirable to examine the position of the bloodvessels about the medullary cones, so far as this can be ascertained by the unaided eye.\nThe renal artery, as it enters the hilum of the kidney, breaks up into four or five branches, and these again subdivide, a few of the branches passing behind the pelvis, while the greater number remain in front ; they pass upwards between the calyces enclosed in folds of the fibrous membrane, and so they come in contact with the sides of the medullary cones. Each cone appears to be supplied by two arterial branches, which, passing up one on each side, form an anastomosing arch\nover the base of the cone (fig. 146). From this arterial arch branches proceed in all di-\nFig. 146.\nSection of the kidney, showing the position of the arterial and venous branches by the sides of the medullary cones, a, a, a, a, arteries ; b, b, b, veins.\nrections, the greater number passing into the cortical substance. The venous branches in this situation likewise form arches over the medullary cones, and have the same general arrangement as the arteries ; they unite into four or five trunks which are placed in front of the pelvis. There is no anastomosis between the arteries of neighbouring cones ; each medullary cone, with its investing cortical substance, corresponds with one of the separate lobules of the embryo kidney; and although in the fully developed human kidney, scarcely any trace of the original lobular division remains, yet the separation of the lobules, so far as their vessels are concerned, remains as complete as it is in the permanently lobular kidney of the porpoise. When an injection is thrown into the vessels of one lobule, that lobule only is injected, without the transfer of the injection through anastomosing vessels to neighbouring lobules. Obstruction of the artery passing to one lobule will effectually prevent the injection of that lobule, while the surrounding parts are completely injected. It occasionally happens during life that the vessels supplying one or two lobules become obstructed, and as a consequence of this obstruction those lobules become atrophied while the rest of the gland is perfectly nourished. Additional evidence of the com-lete isolation of the lobules of the human idney is afforded by certain other pathological conditions, which may, with advantage, be briefly alluded to in this place. Fig. 147 represents a section of a kidney, the glandular structure of which has been destroyed by cysts developed in its substance; the part which remains is a framework or skeleton, consisting of the capsule (a) continuous below with the pelvis (b), which is much dilated,","page":238},{"file":"p0239.txt","language":"en","ocr_en":"REN.\n239\ncompartments, occupy the position of the original interlobular fissures in the embryo kidney, and are analogous to the deep layer of the fascia with its interlobular prolongations\n* Vide ante, p. 233.\nf The drawings are about one-third the natural size ; the preparation from which they are taken is contained in the Museum of King\u2019s College.\nX Monthly Journal of Medical Science, May, 1842\nwhich exist in the kidney of the porpoise.* In this instance the tissue has been condensed and thickened by disease. At d, d there may be seen the rounded openings through which the apices of the medullary cones projected into the calyces. The lobulated character of the surface of the same kidney is represented in fig. 148; the depressions correspond with the fibrous septa, and indicate the position of the original interlobular fissures ; the convexities correspond with the lobules, and have been rendered prominent by a liquid accumulation in the closed cavities formed, as above described, in the substance of the organ.f Reference will hereafter be made to some other morbid conditions of the human kidney which have peculiar characters impressed upon them by these interlobular septa, which are in fact the persistent remains of that interlobular cellular tissue, which is permanently distinct in certain tribes of mammalia, while in most animals of this class, as in the human subject, it remains as a distinct and easily recognised tissue only during f\u0153tal life. In the completely formed kidney it is blended with and concealed by the surrounding tissues, and manifests its presence as it were indirectly, by the peculiar characters which it impresses on the structure of the kidney as shown by the results of injection or in the course of certain pathological changes.\nMinute Structure. \u2014 In this division of our subject, we have to consider, in succession, the following structures.\n1st, The fibro-cellular matrix; 2ndly, The tubes, their course, division, and termination ; 3rdly, The Malpighian bodies, their connexion with the blood-vessels, and with the tubes ; 4thly, The epithelium, in-different parts of the surface over which the urine passes, commencing with that of the Malpighian bodies, and terminating with that of the pelvis and ureter.\nThe fibro-cellular matrix of the kidney has been well and accurately described by Professor Goodsir.J It exists throughout every part of the renal structure. (Fig. 149, c) represents\nFig. 149.\na, b, renal cells from the urine, distended with oil ; c, portion of the fibro-cellular matrix, with one\nwhile the same fibrous membrane is prolonged continuously through the substance of the\nFig. 147.\nkidney to the surface ; the septa (c,c,c), which thus divide the kidney into the various closed\nFig. 148.","page":239},{"file":"p0240.txt","language":"en","ocr_en":"240\nREN.\nlarge oval space, which contained a Malpighian body, and several smaller meshes in which the convoluted tubes were packed ; d, Malpighian capsule and tube, filled with blood from the Malpighian capillaries; e, fibrinous mould of a urinary tube entangling oil globules, from the urine.\na portion from the cortical substance.) It is best examined in a thin section which has been macerated in water for a few minutes, so as to wrash away the tubes and Malpighian bodies. The matrix then appears in the form of a fibrous network, the meshes of which have, for the most part, a circular outline. The smaller meshes are of pretty uniform size, and are accurately filled by the tubes, each tube in its tortuous course passing through very many of the cells formed by this curious and beautiful structure. The meshes do not occupy any one plane or position rather than another, but in whatever direction the section of the cortical substance is made, the same regular network presents itself. When the tubes are in situ, they often appear to be mapped out, as it were, into regular circular or oval portions ; an appearance which has, doubtless, confirmed some observers in the erroneous notion that the tubes terminate in blind extremities. This apparent isolation of the different parts of what is in reality a continuous tube, is very much influenced by the condition of the tube itself. In the normal state, the colour of the tubes often contrasts with that of the matrix, which when free from blood is of a whitish colour, so that the tubes are visible through the substance of the matrix, and the observer can trace the continuity of the tube between the different meshes of the tissue. The same observation applies to the tubes when filled with blood ; in some parts of the specimen portions of the tube appear quite isolated, where they are concealed by the overlying matrix (fig. 150, a a), while in other parts the tubes are more or less distinctly visible through the intervening fibrous tissue (b b). In some parts transverse sections of the tubes are seen, and in other instances a considerable length of tube appears, uncovered by matrix ; this tissue having been removed by the knife, while the tube itself has just escaped the section. In a subsequent part of this article reference will be made to certain pathological changes, as a consequence of which the tubes lose their epithelial lining and become more or less transparent ; and in this condition, when they are packed in the meshes of the fibrous tissue, they have somewhat the appearance of separate globular or oval cells, and they have actually been described as such by an experienced microscopical observer.* This question will be fully considered hereafter, the object of the present brief allusion to it being to show the importance of studying the arrangement of a tissue which gives peculiar appearances to the parts with which it is con-\n* On Subacute Inflammation of the Kidney, by John Simon, Esq. F. R. S., Med. Chir. Transactions, vol. xxx.\nnected, and a misapprehension of which may lead, as it has led, to serious practical errors.\nFig. 150.\nConvoluted tubes filled with blood, as seen when packed in the meshes of the matrix, magnified 200 diameters.\nThe large oval space represented in fig. 149, c, indicates the position of a Malpighian body ; these bodies, as well as the tubes, being accurately fitted into meshes of the fibrous matrix. The arrangement of the fibrous tissue in the medullary cones is somewhat different from that of the cortical portion. The tissue in this part is more abundant, so that the tubes are separated by it to a greater distance than in the cortical portion of the kidney. The hardness and greater cohesion of the tissue of the medullary cones, as compared with that of the cortical portion, is in great part due to the more abundant fibrous matrix in which the tubes of this part are packed. A transverse section of the cones shows the matrix in the form of circular meshes surrounding the tubes, as in the cortical portion ; but on a longitudinal section the meshes appear elongated, thus corresponding in form with the venous capillary meshes which occupy the substance of the fibrous tissue, and which in this part of the kidney are elongated in the direction of the tubes. There being no Malpighian bodies in the medullary cones,\"the larger meshes of the matrix which contain these bodies are not present in this part of the kidney. In order to ascertain the relation which the blood-vessels bear to the matrix, it is necessary to examine portions of a kidney which has been artificially injected, or one in which the vessels are filled with blood. It will then be seen, that while the tubes (fig. 151) accurately fill the meshes of the fibrous tissue, the capillary vessels (b b and c), forming a plexus which surrounds the tubes, are contained in the substance of the same tissue (c c). When the blood-vessels are","page":240},{"file":"p0241.txt","language":"en","ocr_en":"REN.\n241\nempty, they cannot be distinguished from the fibrous tissue in which they are imbedded ; it\nFig. 151.\nSection of the kidney, showing the relation of the tubes and blood-vessels to the fibrous matrix, a, portion of a tube ; b, section of a blood-vessel ; c, fibrous matrix. Magnified 100 diameters: from a specimen prepared by Mr. Bowman.\nis only by the contrast of their colour when filled with blood, or with injection, that it can be ascertained that, in addition to the capillary vessels which surround the tubes, there is a connecting fibrous tissue, the office of which appears to be to support and retain in position the various complicated parts \u2014 tubes, Malpighian bodies, and blood-vessels \u2014 amongst which it is placed.*\nTubuli Uriniferi. \u2014 The tubuli uriniferi are so intimately connected with the Malpighian bodies, that it is not possible to give a complete description of one of these structures without an occasional reference to the other.\nThe general course and mode of division of the tubes, as well as their connexion with the Malpighian bodies, is best ascertained by the examination of specimens in which the\n* Mr. Toynbee, in a paper \u201c On the Minute Structure of the Human Kidney,\u201d i alludes to the presence of \u201c parenchymal cells \u201d in the kidney, to which he assigns an important function in preparing the blood for further changes in the tubuli, in which he says \u201c cells of a character not very dissimilar are seen.\u201d He considers that \u201cthe relation in which the parenchymal cells stand to the nervous system is a subject of great interest;\u201d and he arrives at the conclusion that the nervous filaments \u201c end by becoming continuous with the parenchyma of the organ precisely as he has observed those in the tail of the tadpole to become directly continuous with the radiating fibres of stellated corpuscles, and the filaments from the corpuscles to communicate with each olher.\u201d He further states that in certain diseased states of the kidney, \u201c the parenchymatous cells will be found not merely increased in size, but adipose depositions will be visible throughout them.\u201d The account which Mr. Toynbee gives of these so-called parenchymal cells is not such as will enable me to state with confidence to what particular appearances his description of them applies ; but as I have never been able to satisfy myself of the existence of any such cells as those referred to by him, and as I am not aware that they have been recognized by those anatomists who have most carefully studied the structure of the kidney, I cannot confirm Mr. Toynbee\u2019s observations as to their function, their connexion with the nerves, or the pathological changes which they undergo.\n1 Med. Chir. Trans., vol. xxix. VOL. IV.\ntubes have been filled by injection ; but our knowledge of the essential structure of the tubes, and particularly of their epithelial lining, would be very incomplete without a careful examination of uninjected specimens with a high magnifying power.\nMode of injecting the Tubes. \u2014 The tubes may be more or less completely injected in two modes : 1st, by a liquid thrown into them from the pelvis of the kidney ; and 2dly, by the extravasation of materials forcibly injected into the blood-vessels of the Malpighian bodies. By the first mode the injected materials are made to enter the open mouths of the tubes at one extremity, and to pass towards the other, which, as will presently be shown, is a closed extremity ; while by the second method the injection is admitted into the closed extremities of the tubes, whence it flows towards their open mouths, and so in some instances escapes into the pelvis of the kidney. By the last mode the tubes are often completely filled from one extremity to the other, while by the first method of injection they are generally very imperfectly filled, and this even when the air-pump has been used to aid the flow of the injection into the tubes. A consideration of the structure and relation of the tubes will show that this result is a necessary consequence of the anatomical disposition of the parts. Mr. Bowman remarks *, \u201c To those who are acquainted with the practical difficulties of the injection of the ducts of glands in general, and especially of those which are very tortuous, the following considerations on this subject will probably appear conclusive. Even of the testis (where the tubes are far thicker and stronger in their coats, and much more capacious than in the kidney), there are not ten specimens that can be pronounced at all full in the museums of Europe : and there is no evidence that, even in the best of these, the injected material has reached the very extremities of the tubes. In the kidney, the tubes are exceedingly tortuous after leaving the Malpighian bodies, and only become straight, in most animals, in proceeding towards the excretory channel to discharge themselves. The way towards their orifices is so free in a natural state, that their fluid contents exert no distending force upon their walls. Accordingly their walls are exceedingly feeble ,\u2022 the basement membrane on which their strength mainly depends is very delicate, and easily torn. They are therefore incapable of offering much resistance to a fluid impelled into them from the pelvis, but burst easily if it be forcibly urged. But were the coats ten times as tough as they really are, injection could not penetrate far into their convoluted portion, unless pushed with much force ; and this for two reasons : 1st, the fluid which the tubes already contain has no means of escape before the injection, since these canals end by blind extremities in the Malpighian bodies ; 2dly, the layer of epithelium is, immediately after death, very prone to separate\n* Philosophical Transactions, 1842.\nR","page":241},{"file":"p0242.txt","language":"en","ocr_en":"24-2\nREN.\nfrom the basement membrane which it lines, and to fall into and block up its narrow channel.\u201d It consequently happens that, in face of mechanical obstacles such as those above mentioned, the force employed to inject the tubes sooner or later bursts their coats ere their extremities have been reached.*\nCourse and Termination of the Tubes.\u2014Tracing the tubes from the apex of a medullary cone, on the surface of which their open mouths may be seen, we find them taking a straight course through the pyramid, branching dichotomously and diverging as they proceed {fig. 143). After reaching the base of the pyramid, their course through the cortical portion is very various ; many tubes immediately take a very tortuous course, some of them bending down into the inter-pyramidal portions of the cortical substance, while those near the centre of the pyramid pass onwards in a mass and in a straight line towards the surface, the tubes on the sides of the bundle in their progress passing off successively in a tortuous course through the cortical substance, so that only a few of the central tubes in each bundle retain their straight course quite up to the surface of the kidney ; these finally turn backwards, making many convolutions in the cortical substance. After leaving the medullary cones, the branching of the tubes, except in very rare instances, appears to cease ; occasionally two tubes in the cortical substance unite in passing towards the cones ; and I once saw this occur at a very short distance below the Malpighian bodies, so that two short tubes, each with a Malpighian body at its extremity, united into one common tube. Some distinguished anatomists have maintained that the tubes, after dividing in the cortical substance, reunite in a plexiform manner, and they have described this as their natural\n* In opposition to the opinion of Mr. Bowman, supported as it is by facts and arguments which, to most practical anatomists who are acquainted with the structure and relations of the tubes and Malpighian bodies, will appear quite conclusive, Mr. Toynbee states that the possibility of injecting the entire length of th\u00e9 tubes, and even the Malpighian capsules from the pelvis of the kidney, is abundantly roved by many of his own spechnens, in which the Ialpighian bodies are in this way distended, and that without any extravasation into the vascular tissues. If the account which Mr. Bowman has given of the connexion of the tubes with the Malpighian bodies be a correct one, it is clearly impossible that the tubes, long, tortuous, closed at their extremities, and always containing more or less liquid, can be completely injected from the pelvis of the kidney, unless the rapture of the tube or of the Malpighian capsule allows the liquid contents of the tube to give place to the injected material. Certainly the Malpighian capsules cannot possibly be injected from the tubes so long as the tubes and the capsules remain entire. If, therefore, Mr. Toynbee is correct in his observation on this point, the ex-lanation of the fact must, as I think, be that which\nhave given. His account of the Malpighian bodies (Med. Chir. Transactions, vol. xxix. p. 311), and of their relation to the tubes, so far as I can comprehend the description given, appears to be incorrect ; and his diagrams of these bodies (Plate 8, loc. cit.) represent appearances such as I have never observed in the course of my own examinations.\nmode of termination. This opinion is in all probability founded on deceptive appearances, such as must often have presented themselves when the means of observation were less perfect than they now are, and which even at this time are but of too frequent occurrence. It appears to be a general fact that the tubes divide in their course from the apices of the medullary cones towards their opposite terminations, but they never reunite while passing in this direction. Other anatomists have considered the tubes to terminate in free blind extremities unconnected with the Malpighian bodies ; and they have based their opinion on the appearances of injected specimens as well as on those of recent ones. With reference to this question Mr. Bowman* remarks, \u201c As the injection always stops short of the real extremities of the tubes, it must necessarily show apparent free extremities\u2014and others may be produced by the section requisite for the examination of the part. As for the false appearances presented by recent specimens, they are obviously referable to the sudden bending down of a tube behind the part turned to the observer. In a mass composed of convolutions, many such must continually occur ; and their real nature may be easily determined by the use of a high power and varying focus.\u201d In addition to the sources of fallacy thus alluded to by Mr. Bowman, there is another, to which I have already referredf in describing the fibrous matrix in which the tubes are packed. To an inexperienced observer, few appearances could be more deceptive than the apparent abrupt terminations of the tubes, as these are seen in the spaces formed by the surrounding tissue, here visible in the meshes of the network, and there suddenly concealed as they pass beneath the fibrous tissue.\nThe manner in which the tubes actually terminate is by becoming continuous with the Malpighian bodies. This fact, which can be demonstrated in many of the tubes, is a matter of fair inference and of moral certainty in the case of every tube. The proofs of this fact, and the precise mode of continuity, we shall presently proceed to examine.\nStructure of the Tubes.\u2014The uriniferous tubes contain the two structures which usually compose the mucous tissue, viz. the basement membrane and the epithelium.J\nThe basement membrane is a thin transparent homogeneous lamina, simple and entire, without any aperture or appearance of structure. It forms the parenchymal wall of the uriniferous tubes ; gives them their form, size, and stability ; is in relation, on the one hand, with the vascular system of the organ and the investing fibrous matrix, and on the other, with the epithelial lining of the tubes. The epithelium adheres to the inner surface of the membrane by organic union : it sometimes separates readily after maceration in water, and in some forms of chronic inflammation of\n* Loc. cit.\nf Vide ante, p. 239.\nX Vide art. Mucous Membrane.","page":242},{"file":"p0243.txt","language":"en","ocr_en":"REN.\n213\nthe kidney it frequently happens that the epithelial lining of many of the tubes is entirely removed, or only a few particles of epithelium remain scattered over the inner surface of the membrane. \u201c It sometimes happens, that when the epithelium may seem to be altogether detached, the basement membrane retains, scattered evenly over its surface and at some distance apart, a number of roundish marks, of the size and aspect of the nuclei of epithelium particles. These are most probably the early condition of the new or advancing series of these particles.\u201d* The basement membrane is united externally to the capillary venous plexus and the investing fibrous matrix ; there is probably some organic connexion between these tissues, which allows of the free transudation of materials from the blood-vessels through the basement membrane to the epithelial cells. When a tube deprived of its epithelium is detached from the surrounding tissue, the basement membrane is readily thrown into folds and wrinkles, and appears to possess a considerable amount of elasticity. The thickness of this membrane, according to Mr. Bowman, does not exceed __i__th of an English inch. In certain diseased states of the kidney its thickness is much increased, and simultaneously the cavity of the tube becomes dilated so as greatly to exceed its normal diameter, thus constituting the serous cysts which are so frequently observed in the kidney.\nThe basement membrane of the tubes is continuous on the one hand with the capsule of the Malpighian bodies, and on the other through the straight tubes of the pyramids with the basement layer of the mucous membrane which lines the pelvis of the kidney.\nThe mean diameter of the tubes is about \u20225.1^ inch. The entire diameter of the convoluted tubes in the cortical portion somewhat exceeds that of the straight tubes in the pyramids, although the cavity of the latter is greater than that of the former. The latter fact resulting, as will be seen hereafter, from the difference in the character of the epithelium in these portions of the tubes.\nAfter the brief allusion just now made to the epithelium of the tube and its relation to the basement membrane, it will be more convenient to postpone for the present the particular consideration of this important structure, and to proceed to the examination of the Malpighian bodies. We shall then revert to the epithelium, and we shall find that the varying characters which it presents in different parts of the organ are of the greatest interest and importance in connection with the physiology of the renal secretion, as well as on account of the assistance which they afford in the interpretation of the pathological changes to which the kidney is liable.\nMalpighian Bodies. \u2014 The Malpighian bodies have been objects of much interest since their discovery by the distinguished anatomist whose name they bear. Malpighi j-\n* Art. Mucous Membrane.\nf Exercitatio Anatom, de Renibus.\nascertained that these bodies, which he calls internal glands, could be readily injected from the arteries, to the branches of which they are appended. He could not succeed in injecting them from the veins, in consequence, as he believed, of valves in these vessels preventing the passage of the injected material in a backward direction ; he, however, considers it a rational inference, that the venous radicles commence in these bodies. Malpighi further endeavoured to demonstrate the connection which he believed to exist between these bodies and the urinary tubes. He made unsuccessful attempts to inject the tubes from the arteries and from the veins : and, finally, he experimented on a living dog, by tying the renal veins and the ureters. On examination of the kidneys after death, there were some appearances of the renal glandules (the Malpighian bodies) and the tubes being connected and continuous ; but he confesses that his opinion on this point was derived rather from analogy than from ocular demonstration, his idea being that the urinary constituents were separated from the arteries of the Malpighian bodies, and that the tubes were the excretory ducts of these glands.\nRuysch* appears to have been the first to show that the urinary tubes may be injected through the arteries of the Malpighian bodies, and he supposed that the arteries become directly continuous with the urinary tubes. Boerhaave f described the cortical portion of the kidney as being composed partly of glandular Malpighian bodies, and partly of bloodvessels, which form a plexus without being connected with the Malpighian bodies ; he also inferred the existence of two kinds of excretory ducts, the one kind being connected with the Malpighian bodies, while the others are directly continuous with the blood-vessels ; and he supposed that the more watery portion of the urine is excreted by the latter, while the denser portion prepared in the Malpighian bodies is carried off by the first-mentioned ducts. Bertin J agrees for the most part with Boerhaave as to the anatomy of the kidney, but he assigns to the Malpighian bodies the office of secreting the more liquid portion of the urine, and supposes that the denser parts are separated by those blood-vessels which, as he believed, are not connected with the Malpighian bodies, but are directly continuous with the urinary tubes.\nSchumlansky \u00a7, while he confesses the great difficulty of arriving at an accurate knowledge of the structure of the Malpighian bodies and their connexion with the urinary tubes, appears to have had as definite an idea of these parts as it was possible to arrive at with the imperfect means of observation which he possessed. He describes the Malpighian bodies as consisting of a glomerulus of vessels, connected on the one side with the arteries, and\n* Thesaurus Anatom.\n+ Institut. Medic.\nJ Mem. de l\u2019Acad. Roy. des Sciences, 1744\ncit.\n\u00a7 De Structura Renum.\nArgent. 1788.\nR 2\nOp.","page":243},{"file":"p0244.txt","language":"en","ocr_en":"REN.\n244\non the other with the veins, and invested by a cellular tissue in a manner which he does not very clearly explain. He believes that there is a close connexion between the Malpighian bodies and the tubes, as manifested by the fact, that the tubes may be filled by a forcible injection of the Malpighian bodies through the arteries : further confirmation of this fact being afforded by the occasional passage of blood and other materials through the same channels, and the tubes being found filled with blood after death. With respect to the last observation, which he quotes from Bertin, he appears to have some doubt, and suggests that the vessels containing the blood may have been blood-vessels, and not urinife-rous tubes.\nSince the time of Schumlansky, whose work above quoted was published in the year 1788, scarcely any addition was made to our knowledge of the structure of the Malpighian bodies until the publication of Mr. Bowman\u2019s paper*, already so often referred to. In some respects, indeed, the description given of the Malpighian bodies by the best anatomists immediately before the appearance of Mr. Bowman\u2019s paper, is less accurate than that of Schumlansky, and some of his predecessors. Thus, Miillerf denied, in the most positive manner, the existence of any connexion between the Malpighian bodies and the tubes, and the possibility of injecting the latter from the former. Professor M\u00fcller has since J acknowledged and confirmed the accuracy of Mr. Bowman\u2019s observations, which I shall now proceed to detail as much as possible in his own words, because it would be impossible to depart much from the language of his paper without incurring a risk of losing something of the clearness which characterises the original.\nThe Malpighian bodies consist of a rounded mass of minute blood-vessels, invested by a cyst or capsule. The capsule was first particularly described by M\u00fcller, who believed it to be closed on all sides except at one point, where it is perforated by the blood-vessels. He accurately described the arterial branch as passing into the cavity of the capsule, where it gives off tortuous branches, which form arches, and then return to the point at which the artery enters, so that the tuft of vessels is free in the cavity of its investing capsule, being connected with the latter only at one point. Mr. Bowman, observing that the capsule of the Malpighian bodies had an appearance precisely similar to that of the basement membrane of the tubes, and seeing these similar tissues in such close proximity, was led to suspect that the capsule was in fact the basement membrane of the tubes expanded over the vessels, and after some time he succeeded in obtaining an unequivocal view of\n* On the Structure and Use of the Malpighian Bodies of the Kidney. Philos. Trans, part i. 1842.\nf J. M\u00fcller, de Glandularum Secernentium Structura Penitiori. Lips. 1830.\nJ Untersuchungen \u00fcber die Eingeweide der Fische. J. M\u00fcller, Berlin, 1845.\ntheir continuity. This important result was arrived at after the use of the double injection. After the injection of some kidneys through the artery by this method, it was found that the injected material had in many instances burst through the tuft of Malpighian vessels, and being extravasated into the capsule, had passed off along the tube. (Figs. 153.3.156,157.) Mr. Bowman afterwards made numerous injections of the human kidney, and of that of many of the low^er animals, and in all, without exception, he met with the same disposition. He also examined thin slices of the recent organ with high powers of the microscope, and in this manner fully corroborated the evidence furnished by injections. This mode of examination likewise led Mr. Bowman to the very interesting discovery of ciliary motion within the orifice of the tube and the contiguous portion of the Malpighian capsule. According to the observations of Mr. Bowman, the circulation through the kidney may be stated to be as follows : \u2014 \u201c All the blood of the renal artery (with the exception of a small quantity distributed to the capsule, surrounding fat, and the coats of the larger vessels,) enters the capillary tufts of the Malpighian bodies; thence it passes into the capillary plexus surrounding the uriniferous tubes, and it finally leaves the organ through the branches of the renal vein.\u201d (Fig. 152.)\nFig. 152.\nPlan of the renal circulation in Mammalia.\n(After Bowman.')\nThe relative proportions and the character of the several parts are accurately copied from preparations of the human kidney. The artery, a, is seen giving a terminal twig, f, to a Malpighian tuft, m, from \u25a0which emerges the efferent (or portal) vessel, d. Other efferent vessels are seen, e, e, e. All these enter the plexus of capillaries, p, surrounding the uriniferous tube, t. From this plexus the emulgent vein, g, springs. Supposed to be magnified about forty diameters.\nFollowing it in this course, I shall now give Mr. Bowman\u2019s description of the vascular apparatus, and the nature of its connexion with the tubes. I shall also refer to some observations which have been made since the publication of Mr. Bowman\u2019s paper, premising that Mr. Bowman\u2019s description is so singularly accurate that it scarcely requires or admits of any, even the slightest, addition or modification, with reference to those particulars which it embraces.","page":244},{"file":"p0245.txt","language":"en","ocr_en":"REN.\nWith the inconsiderable exceptions above mentioned, the terminal twigs of the artery correspond in number with the Malpighian bodies. Arrived here, the twig, which is usually of considerable length, although occasionally very short, perforates the capsule, and, dilating suddenly, breaks up into two, three, four, or even eight branches, which diverge in all directions like petals from the stalk of a flower, and usually run in a more or less tortuous manner, subdividing again once or twice as they advance over the surface of the ball they are about to form. (Fig. 153.)\nFig. 153.\n1.\tMalpighian tuft.\u2014Horse. The injection has penetrated only to the capillaries, a, the artery ; f one of its terminal twigs (or the afferent vessel of the Malpighian body) ; d, the dilatation and mode of breaking up of the terminal twig after entering the capsule ; the division of the tuft into lobes, l, l, l, l, is well seen ; i, i, intervals between the lobes. Magnified about eighty diameters.\n2.\tMalpighian tuft. \u2014Horse. The ^ injection has penetrated through the tuft, and has filled the afferent vessel. /, the afferent vessel ; d, its dilatation and mode of division ; m, m, Malpighian capillaries ; e, efferent vessel springing from them, and leaving the capsule between two primary branches of the afferent vessel. Magnified about eighty diameters.\n3.\tMalpighian body. \u2014 Horse. The injection, after filling the primary branches of the afferent vessel, has burst into the capsule, and passed off along the tube. It has not filled the tuft of capillaries, which consequently are not seen, nor has it spread within the capsule over the whole surface of the tuft, f the afferent vessel; d, its dilatation and mode of subdivision ; c, c, the outline of the distended capsule ; t, the tube passing from it ; m, situation of the uninjected Malpighian tuft. Magnified about seventy diameters. (After Bowman.)\nThe vessels resulting from these subdivisions are capillary in size, and consist of a simple, homogeneous, and transparent membrane.\n245\nThey dip into its interior at different points, and, after further twisting, reunite into a single small vessel (fig. 154. 1.), which varies in its size, being generally smaller, but in some situations larger, than the terminal twig of the artery. This vessel emerges between two of the primary divisions of the terminal twig of the artery, perforating the capsule close to the vessel, and, like it, adhering to the membrane as it passes through. It then enters the capillary plexus, which surrounds the tortuous uriniferous tubes. (Fig. 154. 2. and 155.) The\nFig. 154.\n1.\tMalpighian body, &c., from the horse. Malpighian tuft, from near the base of one of the medullary cones, injected without extravasation, and showing the efferent vein branching like an artery, as it runs into the medullary cone, a, arterial branch ; e, the afferent vessel ; m, the Malpighian tuft ; /, the efferent vessel ; b, its branches entering the medullary cone. Magnified about seventy diameters. (After Bowman.)\n2.\tMalpighian bodies, &c., from the horse. The injection has passed, as in fig. 155., but without rapture of the Malpighian tuft, a, branch of the artery; /,/, afferent vessels; m, m, Malpighian tufts ; e, e, efferent vessels ; p, plexus surrounding the tubes ; s t, straight tube in cortical substance ; c t, convoluted tube in ditto. Magnified about thirty diameters.\ntuft of vessels thus formed is a compact ball, the several parts of which are held together solely by their mutual interlacement, for there is no other tissue admitted into the capsule besides blood-vessels. It is subdivided into as many lobes as there are primary branches of the terminal twig or efferent vessel, and these lobes do not communicate, except at the\nr 3","page":245},{"file":"p0246.txt","language":"en","ocr_en":"246\nREN.\nroot of the tuft. There are, therefore, deep clefts between them, which open when the lobes are not greatly distended with injection or blood. (Fig. 153, 1.) The surface of\nFig. 155.\nMalpighian body, tube, &c., from the horse. The injection has penetrated from the artery through the Malpighian tuft into the plexus surrounding the tubes. It has then ruptured the vessels of the tuft, filled the capsule, and passed off along the tube, a, arterial branch ; e, afferent vessel ; c, capsule distended; t, tube; f efferent vessel; p, plexus of capillaries, surrounding other tubes not injected. Magnified about thirty diameters. (After Bowman?)\nthe tuft is everywhere unattached and free, and continuous with the opposed surfaces of the lobes. The whole circumference of every vessel composing the tuft is also free, and lies loose in the cavity of the capsule. These circumstances cannot be seen in specimens gorged with injection, but only by careful examination of recent specimens with a power of 200 or 600 diameters.\nThe vessels are so perfectly bare, that in no other situation in the body do the capillaries admit of being so satisfactorily studied. It is only where the tuft is large, as in man and in the horse, that its lobulated character can be always discerned. Where the number of primary subdivisions of the afferent vessel is smaller, the detection of lobes is less easy ; they may often be seen, however, in the frog. In Birds and Reptiles the afferent vessel seldom divides; but dilates instead into a pouch-like cavity, which, after taking two or three coils, contracts again, and becomes the efferent vessel. There are of course no lobes ; but the surface of the whole dilated part is free.\nThe basement membrane of the uriniferous tube, expanded over the Malpighian tuft to form its capsule, is a simple homogeneous and transparent membrane, in which no structure can be discovered. It is perforated, as before stated, by the afferent and efferent vessels, and is certainly not reflected over them. They are united to it at their point of transit, but in what precise manner Mr. Bowman has not been able to determine. It appears probable that the membrane is reflected to a slight extent upon the afferent and efferent vessels, and that thus the union is effected. The appearance of bulging presented by the distended capsule round the entrance of the afferent vessels in fig. 156. seems to indicate that the membrane is slightly reflected in-\nwards upon the trunks of the vessels, if this term can be correctly applied to such minute\nFig. 156.\nTwo Malpighian bodies injected from the human subject. The tufts are burst and the fluid has escaped into the capsule. In one case it has passed also along the tube, the extreme tortuosity of which at its commencement is well seen, a, arterial branch ; f terminal twigs ; c, c, Malpighian capsules distended; e, the depression often seen in such cases, at the point where the afferent and efferent vessels pass : the latter are not here injected ; t, the tube. Magnified about ninety diameters. (After Bowman.)\nvessels as the afferent and efferent vessels of the Malpighian bodies. Opposite to the point where the vessels perforate the capsule, is the orifice of the tube, the cavity of which is continuous with that of the capsule, generally by a constricted neck. Mr. Bowman has specimens prepared with the double injection, showing this continuity in Mammalia, Birds, Reptiles, and Fish. (fig. 157.)\nA more satisfactory proof of the direct continuity of the cavity of the tube with that of the Malpighian capsule is afforded by a clear view of the whole of the textures magnified 200 or 300 diameters. The capsule may thus be seen to pass off into the basement membrane of the tube as the body of a Florence flask into its neck (figs. 158. and 159.).\nThe basement membrane of the tube is lined by a nucleated epithelium of a finely granular opaque aspect, while the neck of the tube and the contiguous portion of the capsule are covered by a layer of cells much more transparent, and clothed with vibratile cilia. The epithelium appears to be continued in many cases over the whole inner surface of the capsule, while in other instances it is impossible to detect the slightest appearance of it over more than a third of the capsule. When fairly within the capsule the cilia cease, and the epithelium beyond is of excessive delicacy and translucence. Its particles are seldom nucleated, and appear liable to swell by the application of water to the specimen. The cavity existing in the natural state be-","page":246},{"file":"p0247.txt","language":"en","ocr_en":"REN.\n247\ntween the capsule and the vascular tuft, is filled by fluid, in which the vessels are bathed, and which is continually being impelled from the capsule into the tube by the lashing movement of the cilia.\nFig. 157.\na\nThis specimen has been chosen because it exhibits the termination of a considerable arterial branch wholly in Malpighian tufts, and because the several Malpighian bodies injected show different appearances of a very instructive kind, a, arterial branch with its terminal twigs ; at a the injection has only partially filled the tuft, at \u00df it has entirely filled it, and has also passed out along the efferent vessel, e, without any extravasation, at y it has burst into the capsule and escaped along the tube t, but has also filled the efferent vessel e, at 2 and s it has been extravasated and passed along the tube, at m and m, the injection on escaping into the capsule has not spread over the whole tuft. Magnified about forty-five diameters. From the human subject. (After Bowman.')\nThis very interesting phenomenon of ciliary motion in the neck of the tube and in the Malpighian capsule was discovered by Mr. Bowman in the frog ; and at the time when his paper was published he had not observed it in any other animal. Mr. Simon* afterwards observed it, as he says, \u201c at the origin of each uriniferous tubule in the kidneys of various other reptiles, and also with perfect distinctness in the skate.\u201d Bidderf has since observed the same phenomenon in the triton ; KollikerJ has described it in the embryo lizard ; and I have seen it in the common snake.\n* A Physiological Essay on the Thymus Gland, by John Simon, F.R.S.\n\"t Muller\u2019s Archiv. 1845. j Miiller\u2019s Archiv. 1845.\nFig. 158.\nFrom the frog; viewed by transmitted light. Shows the continuity of the Malpighian capsule with the tube, the change in the character of the epithelium, and the vascular tuft, c, basement membrane of the tube ; b, epithelium of the tube ; a, cavity of the tube ; f f basement membrane of the capsule ; d, epithelium of the neck of the tube and of the neighbouring part of the capsule, this epithelium is covered with cilia, which were seen in active motion eight hours after death ; g, detached epithelial particle, more highly magnified, showing the relative length of the cilia, as they appeared in this specimen. The capillaries, m, lie bare in the cavity of the capsule, having entered it near t, where the view is obscured by another tube. Magnified about 320 diameters. (After Bowman.)\nFig. 159.\nMalpighian body from the newt (Triton). This\nR 4","page":247},{"file":"p0248.txt","language":"en","ocr_en":"248\nREN.\nspecimen shows the abrupt termination of the ciliated epithelium, e p, Avithin the capsule, a a, Some rounded particles,which are sometimes seen in considerable numbers, either on the surface or in the wall of the vessels c. The basement membrane of the capsule, b m, beyond the termination of the ciliated epithelium appears quite naked. Magnified 200 diameters.\nI am not aware that ciliary motion has been detected in the kidneys of Mammalia or Birds. I shall presently show that in certain fishes and reptiles the cilia are not confined to the situation in which they were first discovered by Mr. Bowman ; but that they exist throughout the greater part, if not the whole length, of the uriniferous tubes.\nIt appears desirable to allude here to some observations which have been made since the publication of Mr. Bowman\u2019s paper, and to inquire how far certain statements which have been opposed to his account of the Malpighian bodies are worthy of consideration. It is not my intention to occupy time and space, by giving a history of all the contradictory opinions which this subject has elicited. It may be fairly inferred that inability to detect ciliary motion within the Malpighian capsule, or to verify any observation in reference to which several competent authorities are agreed, is the result of some defect in the microscope employed, or in the eye or mind of the observer.\nObjections have been made to two parts of Mr. Bowrman\u2019s description ; first, to his account of the relation which the Malpighian capsule bears to the basement membrane of the tube and to the blood-vessels; and, secondly, to his statement that the Malpighian capillaries lie uncovered within the capsule.\nBidder* made his observations on the kidney of the male triton (Triton t\u00e6niatus). The anterior part of the kidney of this animal is exceedingly well adapted for the investigation in question, since it is very thin and transparent, and is thus fitted for microscopical examination without further artificial preparation by tearing or other means. Bidder believes that the vessels do not perforate the capsule to enter its cavity, as described by Mr. Bowman ; but he considers the basement membrane to be introverted so as to form a covering for the vessels and a complete partition of a semilunar form between the cavity of the tube and that of the Malpighian capsule. I have examined the kidney of the triton with great care, and have satisfied myself that Mr. Bowman\u2019s account of the perforation of the capsule by the vessels is strictly correct, and that there is no partition, but, on the contrary, a free communication, between the cavity of the capsule and the orifice of the tube. When the vessels are distended with blood, they almost fill the capsule ; on the contrary, when they are empty, they shrink into a small compass. I have examined them under both conditions, and could never detect any appearance of a membrane reflected over them. The free communication between the cavity\n* Miiller\u2019s Archiv. 1845.\nof the capsule and the orifice of the tube is sufficiently shown by two phenomena which I have repeatedly witnessed : first, when the cilia are in action, the liquid filling that part of the capsule which is unoccupied by the vessels is freely propelled from the cavity of the capsule into the tube; and, secondly, when water is added to the specimen, loose particles of epithelium from the tube are often driven into the capsule, until they fill that part of its cavity which is not occupied by the collapsed blood-vessels.\nDr. Gerlach * describes and figures the Malpighian capsule as being not a blind termination of the uriniferous duct, but a lateral diverticulum of the same structureless basement membrane which forms the duct ; and he believes that the capsule communicates with the duct by means of a short neck. It is not impossible that there may, in some rare instances, be a diverticulum from a tube as represented by Gerlach ; but as I have never yet seen such a mode of connexion between a tube and a capsule, and as 1 have seen numberless instances of tubes terminating directly in the dilatation which constitutes the Malpighian capsule, I do not hesitate to declare my decided conviction that Mr. Bowman has correctly described the structures in question.j-\nWith reference to the second point above alluded to, namely, to Mr. Bowman\u2019s statement that the Malpighian capillaries lie uncovered within the capsule, the observations of Gerlach deserve more consideration. He states that when the Malpighian capillary network is examined after the capsule has been entirely detached from it, it may be seen in its whole extent covered by a thick layer of nucleated cells, which are continued from the inner wall of the capsule upon the Malpighian vessels ; so that the latter lie introverted within a layer of cells like the intestine within the peritonaeum {fig. 160.); and he supposes that the secreting structure of the Malpighian bodies differs from the ordinary structure of glands\n* Miiller\u2019s Archiv. 1845.\nf Dr. Gerlach\u2019s opinion of the manner in which the tubes are connected with the Malpighian capsules, is founded upon appearances which he observed after injecting the urinary tubules from the pelvis of the kidney. He believes that in this manner he succeeded in filling the Malpighian capsules as well as the tubes, and that, too, as he says, after he had failed in filling these parts by injection of the Malpighian vessels from the artery in the manner before described. ( Vide ante, p. 241.) On a careful consideration of the draAvings by which Dr. Gerlach\u2019s paper is illustrated, there seems reason to believe that the appearances which he describes as Malpighian bodies may result from a sudden bulging of the tubes-produced by forcible distension with the rejected material. (See Miiller\u2019s Archiv., 1845, plate 13.) It cannot be a matter of surprise that a forcible injection of the tubes from the pelvis should give rise to unnatural appearances in these structures; whereas a slow infiltration of injection from the ruptured Malpighian vessels, or an equally slow extravasation of blood during life, while itrfills the capsules and the tubes, leaves these parts as nearly as possible in their normal condition, and affords the most satisfactory evidence as to the nature of their connexion with each other.","page":248},{"file":"p0249.txt","language":"en","ocr_en":"REN.\n249\nonly in the absence of the basement membrane between the vessels and secreting cells. Dr. Gerlach\u2019s figure {fig. 160.) exhibits an\nFig. 160.\nMalpighian tuft of capillaries covered with small transparent nucleated cells. (After Gerlach.')\nappearance which every one must have seen in the tuft of vessels extended from the capsule, but which fails to establish the existence of this epithelial investment of the tuft ; for at the border of the figure the wall of the capillaries is seen actually bare, as described by Mr. Bowman. The fact, however, seems to be, that there do exist, here and there, upon the outside of the capillaries of the tuft, nucleated particles, of an extremely delicate nature, the nuclei sometimes lying isolated in the fork of two vessels, and the substance of the cell not expanding into a continuous covering of the whole tuft. It is possible that these nucleated particles may be rather the nuclei belonging to the capillary wall, than a modified representation of the epithelium of the tube. It is at least certain that they lie sparingly upon the individual vessels of the tuft, and do not form a membranous investment of it as a whole. Mr. Bowman showed me these particles, as I have now described them, some years ago. Their existence does not affect the substantial accuracy of his account of the anatomy of the tuft, nor his view of its special share in the secretion of urine.\nHaving thus briefly alluded to certain parts of Mr. Bowman\u2019s description of the Malpighian bodies, the correctness of which has been questioned, and having shown, as I hope, that only in one minute part of his clear and accurate account of their structure is any modification required, we may proceed to trace the blood-vessels in their course from the Malpighian bodies.\nThe blood, leaving theMalpighian tufts, is conveyed by their efferent vessels to the great renal reservoir, the capillary plexus surrounding the uriniferous tubes {figs. 152. 154. and 155.). The vessels lie in the interstices of the tubes, and everywhere anastomose freely, so that throughout the whole organ they constitute one continuous network, lying on the outside of the tubes, in the substance of the matrix, and in contact with the basement membrane. This plexus is intermediate between the efferent vessels of the Malpighian bodies and the veins.\nThe efferent vessels of the Malpighian bodies are always solitary, and never inosculate with one another : each one is an isolated channel between its Malpighian tuft\nand the plexus surrounding the tubes. They are formed by the union of the capillary vessels of the tuft, and emerge from its interior in the manner already explained. After a course of variable length they open into the plexus. Their size is various. In general they are smaller than the terminal twig of the artery, and scarcely, if at all, larger than the vessels of the plexus into which they discharge themselves. But where the Malpighian tuft is larger, the efferent vessel is usually large also, and divides into branches before entering the plexus. This is eminently the case with those situated near the base of the medullary cones, where the medullary and cortical portions of the organ seem to blend. The efferent vessels from these large Malpighian bodies are often three or four times the diameter of those of the plexus, and take a course towards the pelvis of the kidney between the uriniferous tubes {fig. 154. 1.). They were formerly mistaken for tubes. They branch again and again in the manner of arteries, and form the plexus with long meshes, which invests this part of the tubes. Some of the veins springing from this plexus form the well-known network on the nippleshaped extremities of the cones, around the orifices ; and thence take, with the remainder, a backward course, likewise parallel to the tubes, to empty themselves into various branches that lie about the bases of the cones. The arrangement of the venous radicles on the cortex and on the surface of the kidney has been already described {fig. 145). The veins from the capsule and surrounding fat join the renal vein in some part of its course. It is probable that the capillaries of the vasa vasorum, within the substance of the organ, pour their blood into the capillary plexus surrounding the tubes, as those of the hepatic artery do into the portal hepatic plexus of the lobules of the liver.\nThus, there are in the kidney two perfectly distinct systems of capillary vessels, through both of which the blood passes in its course from the arteries into the veins : the first, that inserted into the dilated extremities of the uriniferous tubes, and in immediate connection with the arteries ; the second, that enveloping the convolutions of the tubes, and communicating directly with the veins. The former, which may be called the Malpighian capillary system, is made up of as many parts as there are Malpighian bodies. These parts are entirely isolated from one another; and as there is no inosculation between the arterial branches supplying them, the blood enters each in a direct stream from the main trunk. Each separate part also of this system has but one afferent and one efferent channel, and both of these are exceedingly small, compared with the united capacity of the capillary tuft. The artery in dividing dilates ; then follow branches which often exceed it in size, and which gradually break up into the finest. The efferent vessel does not usually even equal the afferent, and in size is often itself a capillary. Hence would arise a greater retard-","page":249},{"file":"p0250.txt","language":"en","ocr_en":"REN.\n250\nation of blood in the tuft than occurs probably in any other part of the vascular system ; a delay that must be increased by the tortuosity of the channels to be traversed.\nThe other system of capillaries, or that surrounding the uriniferous tubes, corresponds, in every important respect, with that investing the secreting canals of other glands. Its vessels anastomose with the utmost freedom on every side, and lie on the deep surface of the membrane that furnishes the secretion.\nMr. Bowman has applied the term \u201c portal system of the kidney\u201d to the series of vessels connecting these two, on account of the close analogy it seems to bear to the vena porta, intervening, like it, between two capillary networks, the first of which answers to that in which the vena porta originates, and the second to that in which the vena porta terminates. The capillary plexus surrounding the tubes differs, therefore, from that of other glands, and agrees with that of the liver, in its receiving blood that has previously traversed another system of capillary vessels.\nThe correctness of the analogy which Mr. Bowman has drawn between the circulation of the kidney and that of the liver is very beautifully shown by his observations on the kidney of the boa-constrictor, an animal which may be regarded as the type of those in which, besides the renal artery, the kidney receives a portal vein derived from the hinder part of the body.* Mr. Bowman thus describes the organ in question :\u2014\u201c The kidney of the boa, being composed of isolated lobes of a compressed reniform shape, displays all the points of its structure in peculiar simplicity and beauty. At what may be termed the hilum of each lobe, the branches of the vena porta and duct separate from those of the renal artery and emulgent vein ; the twTo former spreading side by side, in a fan-like form, over the opposite surfaces of the lobe, while the two latter enter its substance and radiate together in a plane midway between these surfaces. The lobe is made up of the ramifications of these four sets of vessels, in the following mode (Jig. 161.). Each duct, as it runs over the surface, sends down a series of branches which penetrate in a pretty direct manner towards the central plane. Arrived there, they curl back, and take a more or less retrograde course towards the surface, and, finally, becoming more convoluted, terminate in the Malpighian bodies, which are all situated in a layer at some distance within the lobe, parallel to the central plane, and nearer to it than to the surface. The ducts never anastomose. The artery subdivides into extremely minute twigs, no larger than capillaries, which diverge on either hand and enter the Malpighian bodies. The efferent vessels are of the same size as the afferent, and, on emerging, take a direct course to the surface of the lobe, and join the branches of the vena porta there spread out. The\n* Vide ante, p. 232-3.\nbranches of the portal vein on the surface send inwards a very numerous series of twigs\nFig. 161.\nfIV______\nPlan of the arrangement of the elements of the kidney, in the boa constrictor, by Mr. Bowman.\na, arterial branch in the centre of the lobule, sending afferent twigs to the Malpighian bodies on each side. The efferent vessels are seen running to the branches of the portal vein, pv,pv, on the surfaces of the lobule. The plexus surrounding the tubes is seen at p, running from the portal vein to the emulgent vein, e v, which lies in company with the artery in the centre of the lobule. The uriniferous tube, t, is seen commencing in the M. body, and passing to the branch of the ureter, ur, ur, at the surface of the lobule where it accompanies the portal vein. The M. bodies are seen diminishing in size, as the tubes become shorter towards the thin edge of the lobule b.\nof nearly uniform capacity, and only a little larger than the vessels of the capillary plexus, in which they almost immediately terminate. This is the plexus surrounding the uriniferous tubes. It extends from the surface to the central plane of the lobe, and there ends in the branches of the emulgent vein.\u201d\n\u201c Thus the efferent vessels of the Malpighian bodies are radicles of the portal vein, and, through the portal vein, empty themselves, as in the higher tribes, into the plexus surrounding the uriniferous tubes. The only real difference between this form of kidney and that of Mammalia is that there is here a vessel bringing blood that has already passed through the capillaries of distant parts, to be added to that coming from the Malpighian bodies, and to circulate with it through the plexus surrounding the tubes. The efferent vessels of the Malpighian bodies run up to the surface, in order to throw their blood through the whole extent of the capillary","page":250},{"file":"p0251.txt","language":"en","ocr_en":"REN.\n251\nplexus ; which they would fail to do if they entered it in any other part.\u201d\n\u201c I have described the renal artery as being spent upon the Malpighian bodies ; but in the hilum of the lobe it gives off, as in the higher animals, a few slender twigs to the coats of the excretory ducts, and of the larger vessels. The capillaries of these twigs are easily seen, and, in all probability, discharge themselves into the branches of the portal vein.\u201d\nIt will appear on referring to the plan (fig. 161.), that there is a direct relation between the size of the Malpighian bodies and the width of the lobe. At the apex of the lobe, where the uriniferous tubes are comparatively short, the Malpighian bodies are of small size, while at the base of the lobe, where the tubes are longer, the Malpighian bodies present a corresponding increase of size. It will presently be seen that this and other facts in the anatomy of this form of kidney, afford very important evidence as to the nature and office of the Malpighian bodies.\nMr. Bowman thus draws a comparison between the circulation through the kidney of the Boa and that through the liver : \u2014 \u201c The circulation through this form of kidney may be aptly compared with that through the liver, as described by Mr. Kiernan in his invaluable paper on that gland. The plexus surrounding the tubes corresponds with the portal-hepatic plexus, which, in the lobules of the liver,invests the terminal portions of the bile-ducts. Both these plexuses are supplied with blood by a portal vein, derived chiefly from the capillaries of distant organs, but in part from those of the artery of the respective organs themselves. The only difference seems to be, that, while in the liver the branches of the artery are entirely given to the larger bloodvessels, ducts, &c., in the kidney a few only are so distributed, the greater number going through the Malpighian bodies, to perform an important and peculiar function. In both glands, however, all the blood of the artery eventually joins that of the portal vein. The emulgent vein of the kidney answers to the hepatic vein of the liver.\u201d\n\u201c The comparison between the hepatic and the renal portal circulation may be thus drawn in more general terms. The portal system of the liver has a double source, one extraneous, the other in the organ itself ; so the portal system of the kidney, in the lower tribes, has a two-fold origin, one extraneous, the other in the 'organ itself. In both cases the extraneous source is the principal one, and the artery furnishing the internal source is very small. But in the kidney of the higher tribes the portal system has only one internal source, and the artery supplying it is proportionably large.\u201d\nMr. Bowman has ascertained that in all the vertebrate classes the Malpighian bodies have essentially the same structure; the capsule being formed by the dilated extremity of a uriniferous tube, into which a single mass of blood-vessels is inserted. But in some orders\nof animals there are modifications which merit notice. The most considerable of these regard the size of the Malpighian bodies. The following table from Mr. Bowman\u2019s paper exhibits their size in a few species, and subjoined to each measurement is that of the tube soon after its emergence. It will be seen that the diameter of the tubes varies far less than that of the Malpighian bodies.\nTable of the Diameter of Malpighian Bodies, and of the Tubes emerging from them, in fractions of an English inch.\n\tDiameter of Malpighian Bodies.\t\t\tDiameter of Tubes. .\n\tMax.\tMean.\tMin.\t\nMan\th\t737\t1 737\ti 7F3\nBadger\tih\t727\t1 733\t1 775\nDog\tih\t733\t753\t653\nLion\ti 70\tS3\t93\t372\nCat\t1 T5(>\t230\t553\tl 680\nKitten\tm\t200\t372\t7M3\nRat\ti 753\t783\t535\t773\nMouse\t553\t533\tl 375\t1 770\nSquirrel\t\t237\t\t773\nRabbit\t...\t1 15\u00d6\t...\t523\nGuinea Pig\t...\t553\t...\t533\nHorse\t1 55\tl 75\t1 53\t1 iT6\nParrot\t\tl 730\t...\t333 ^735\nTortoise\t...\t573\t...\t7S3\nBoa\t533\t733\t1 573\t1 5\u00ce0\nFrog\t\t1 250\t...\t\nEel\t...\t1 537\t...\t\u2022 \u2022 \u2022\nAccording to Professor Miiller* the kidney of the myxinoid fishes has a very simple structure. Before the publication of Mr. Bowman\u2019s paper Miiller described the kidney of these fishes, as consisting of a long ureter extending on each side of the intestine, and sending off at intervals a small sac which terminates in a second closed sac, the junction of the two sacs being marked by a constriction. In the cavity of the closed sac there is a globular tuft of vessels, which is free on all sides except at one point, where the vessels pierce the investing capsule {fig. 162.). Prof. Miiller, from a comparison of his own observations with those of Mr. Bowman, infers that the short tubes proceeding from the ureter in these fishes are analogous to the uriniferous tubes in the more highly organised kidneys, while the closed sac at the extremity of the tube is analogous to the Malpighian capsule ; so that each renculus in the myxinoid fish consists of an exceedingly short uriniferous tube terminating in a capsule, in which is suspended a globular tuft of vessels. The arterial branches which come directly from the aorta terminate, as in the higher animals, by piercing the capsule and forming a globular tuft within it. Miiller had not an opportunity of tracing the exact distribution of the\n* Untersuchungen \u00fcber die Eingeweide der Fische. Berlin, 1845.","page":251},{"file":"p0252.txt","language":"en","ocr_en":"252\nREN.\nblood after leaving the capsule, but he thinks it probable that the veins form a plexus on\nFig. 162.\n\u20222 1\na\n1.\tThe anterior extremity of the kidney of the Bdellostoma Forsteri, of the natural size.\na, the ureter ; b, a short uriniferous tube proceeding from it ; d, the capsule at the extremity of the tube ; /, the arterial branch entering the capsule ; g, the anterior blind extremity of the ureter.\n2.\tDistribution of the blood-vessels in the kidney of the Bdellostoma Forsteri.\nA, the ureter ; B, a uriniferous canal proceeding from it ; C, section of the capsule covering th\u00eb bloodvessels ; D, the vascular mass injected ; a, the afferent vessel of the same ; b, the efferent vessel ; e, an artery unconnected with the vascular mass distributed to the ureter ; d, a branch of the renal vein. This figure is slightly magnified. {After M\u00fcller.')\nthe outer surface of the tubes. It is to be regretted that Miiller has not given some account of the microscopic appearances presented by the inner surface of these tubes, since without some observations on this point, and particularly with reference to the character of the epithelium, it is not possible to form a definite notion as to the exact nature of the parts in question.\nEpithelium. \u2014 In examining the epithelium of the kidney, it will be convenient to commence with that of the Malpighian bodies, and thence to trace this structure through the tubes into the pelvis and ureter. It is scarcely possible to overestimate the importance of a careful study of the epithelial cells in different parts of the kidney, since accurate observations upon this point must form the basis of an exact knowledge of the physiology of the gland, and of the pathological changes to which it is liable.\nEpithelium of the Malpighian bodies. \u2014 With reference to the epithelium of the Malpighian bodies, it will suffice to recapitulate here what has already been fully detailed in speaking of the structure of these bodies. The epithelium of the Malpighian bodies consists of two distinct portions: first, that which covers the\nvessels ; and, secondly, that which lines the capsule. The vessels of the Malpighian tuft appear to have in many instances a more or less complete investment of small, delicate, and transparent nucleated cells. (Fig. 160.) These cells differ entirely from those on the inner surface of the capsule, as well as from those which line the urinary tubes. The epithelium covering that part of the capsule which is contiguous to the orifice of the tube is very transparent, and clothed with vibratile cilia. This ciliated epithelium covers about one-third of the inner surface of the capsule ; beyond this point the cilia cease, and the epithelium is of excessive delicacy and translucence (figs. 158. and 159.), while in many instances it is impossible to detect the slightest appearance of epithelium beyond the line where the cilia cease. The cilia in this situation have been observed only in reptiles and fishes, but they probably exist in all classes of Vertebrata.\nEpithelium of the uriniferous tubes. \u2014 The epithelium of the uriniferous tubes presents itself in two distinct forms, the one kind existing in the convoluted tubes of the cortex, and the other in the straight tubes of the medullary cones. The epithelium in that part of the uriniferous tubes immediately continuous with the Malpighian capsule, presents the same characters as that which covers the contiguous portion of the capsule, consisting of delicate transparent particles, which in fishes and reptiles are furnished with vibratile cilia.\nIn the remaining portions of the tubes which intervene between the neck of the Malpighian capsules and the bases of the medullary cones, the epithelium presents itself under the form to which the term spheroidal or glandular is commonly applied.* The particles are of a more or less rounded form, and are thus distinguished from the flattened cells of the lamelliform or scaly variety of epithelium. (Fig. 163.) They usually form a single layer\nFig. 163.\na\tb\na,\tportion of a convoluted tube from the cortex of the kidney, showing the appearance of its epithelium.\nb,\tportion of a straight tube with its epithelial lining from a medullary cone. Magnified 200 diameters.\n* Vide article Mucous Membrane.","page":252},{"file":"p0253.txt","language":"en","ocr_en":"REN.\t253\ncovering the surface of the basement membrane. They are granular and opaque, and appear to contain a considerable quantity of solid matter. The cell wall is very delicate, and when water is added to the specimen, the cells frequently fall in pieces very rapidly. In this respect the cells of the kidney differ remarkably from the hepatic cells, the latter having a much thicker and firmer wall, which offers a greater resistance to the action of water. The cells have a distinct nucleus, and in the centre of this in many instances a nucleolus is clearly visible. (Fig. 164.)\nFig. 164.\na, b, c, d, epithelial cells from a healthy kidney. a contains no oil ; b, c, d, contain a few small oil globules in their interior, e, f, g, h, epithelial cells from a kidney affected with fatty degeneration ; the oil globules are much larger and more numerous than in the cells from the healthy kidney, m, portion of a urinary tube from a kidney affected with fatty degeneration, k, l, fibrinous moulds of the urinary tubes from the urine of a patient with fatty degeneration of the kidney, each cylindrical mould entangles blood corpuscles, and a cell having a considerable number of oil globules in the interior. Medic. Chir. Trans, vol. xxix. Magnified 400 diameters.\nAnother interesting feature in the renal secreting cells consists in their containing in some cases minute particles of oil. In a perfectly healthy kidney, the quantity of oil contained in the epithelium is very small ; sometimes, indeed, it is difficult to find any cells which contain even the most minute particles of oil, while in other instances, where there is every reason to consider the organ quite healthy, the quantity of oil is much more considerable. When this material accumulates beyond a certain extent which it is difficult to define, it must be considered as morbid, and a great excess of oil in the secreting cells constitutes a main feature of one of the most serious and intractable diseases to which the kidney is liable.\nThe epithelium lining the straight tubes of the pyramids differs essentially from that of the\nconvoluted tubes ; the latter, as before stated, is the true spheroidal or glandular variety of epithelium ; while the former approaches more nearly to the lamelliform or scaly variety. Its particles are smaller and more flattened, so that the epithelium in the medullary cones constitutes a much smaller proportion of the thickness of the tubes than does that in the convoluted tubes of the cortex. (Fig. 163. b.) The canal of the tubes in the medullary cones is also greater in proportion to the thickness of the wall than in the convoluted tubes. The cells in this portion of the tubes have uniform, smooth, and transparent walls, and their interior is less opaque and granular than is the case with the glandular cells before described. Another distinctive character consists in the fact of these cells seldom, if ever, containing oil.\nCiliary motion in the tubes. \u2014 The preceding description of the epithelial lining of the uriniferous tubes corresponds in most particulars with the usually received account of these structures. There now remain to be stated certain facts which probably are not generally known even to those who are accustomed to make microscopical examinations of the kidney. In 1845, A. K\u00f6lliker published a short paper *, in which he mentions the interesting fact, that in the kidney of the embryo lizard the uriniferous tubes are lined by an epithelium remarkable for distinctly developed ciliary processes, which may be seen in vigorous action for some time after the death of the animal. The ciliated epithelium, according to Kolliker\u2019s observation, exists throughout the whole length of the tubes, except at the extremities next the common excretory duct. He also observed the cilia at the entrance of the Malpighian capsule. In a note appended to the same paper, the editor (J. M\u00fcller) states that he has observed the same phenomenon in the uriniferous tubes of a fish (Raia clavata). The cilia are very large and long ; they are directed along the axis of the tube, and have a wavy motion like that of a whip-lash.\nIn the spring of the present year, before I was aware of the observations just now referred to, while examining the kidney of the newt (Triton and Lissotriton), I was surprised to find vibratile cilia in active motion, not only within the Malpighian capsule as described by Mr. Bowman in the frog, but apparently extending throughout the whole length of the uriniferous tubes. I have since looked for this wonderful phenomenon in many of the animals just now mentioned, and have never failed to detect it in any one of the kidneys examined. The part of the kidney most favourable for the examination of this ciliary motion is the anterior extremity, where it is very thin and transparent, so that after being cut away with sharp scissors it requires no further preparation for micro-\n* Ueber Flimmerbewegungen in den Primordial-Nieren. M\u00fcller\u2019s Archiv. 1845, and Edinburgh Med. and Surg. Journal, vol. lxviii.","page":253},{"file":"p0254.txt","language":"en","ocr_en":"254\nREN.\nscopical examination. In a part thus prepared, I have sometimes seen the cilia in rapid action throughout the whole length of every tube in the field of the microscope, and a more wonderful or beautiful sight can scarcely be imagined. The motion commences within the Malpighian capsule ; the little particles floating in the liquid of the capsule are darted into the orifice of the tube with marvellous precision, and thence they are directed onwards through the windings of the tube in a current of liquid, which is propelled with great regularity and speed. Much violence in tearing up the specimen for examination appears to arrest the motion ; and when water is added to the preparation, the epithelial particles swell and fill up the cavity of the tube, and so the motion is retarded. When the cilia are in slow motion, their form and the direction of their movement may easily be seen ; but when the motion has entirely ceased, I have never been able to see them distinctly, even with the best object glasses. The motionless cilia appear to collapse and fall upon the surface of the epithelium, and so become invisible. Since my attention was first directed to the phenomenon in question, I have had but little time to search for it in other animals ; but there appears reason to believe that it exists in most of the higher animals, and probably even in man. The result of my own observations may be thus briefly stated : \u2014 In the newt I have searched for ciliary motion in the tubes many times, and have never failed to find it in any kidney which I have examined. I have searched for it in the frog twice (i. e. in two individuals), and found the ciliary motion very distinct in a considerable portion of one tube. I have examined one snake, and observed the motion very distinctly throughout a large extent of several of the tubes, as well as in the Malpighian capsules. I have searched for the phenomenon in the kidneys of some of the smaller Mammalia, as, for instance, in the mouse and the rabbit, but hitherto without success. I am not aware that any other observations with reference to this subject have been published, but possibly there may be some with which I am not acquainted.\nEpithelium of the pelvis and ureter. \u2014 The epithelium of the pelvis and ureter requires only a brief mention ; it belongs to the lamel-liform or scaly variety, and consists of flattened, delicate, transparent scales, having an angular outline caused by their lateral apposition, and a nucleus which is generally eccentric.\nFunction of the Malpighian bodies and urini-ferous tubes. \u2014 Before concluding this part of our subject, it appears desirable to make some allusion to the probable office of the several parts of the kidney, whose structure has passed under review. Mr. Bowman, in the paper to which reference has so often been made, has propounded a theory as to the office of the Malpighian bodies which I believe will soon be admitted as a true and well-established doctrine, based as it is upon\naccurate observation, and confirmed by sound reasoning and analogy. The theory in question, and the facts and arguments in support of it, are thus clearly stated by Mr. Bowman : \u2014\n\u201c Reflecting on this remarkable structure of the Malpighian bodies, and on their singular connection with the tubes, I was led to specu late on their use. It occurred to me that, as the tubes and their plexus of capillaries were probably, for reasons presently to be stated, the parts concerned in the secretion of that portion of the urine to which its characteristic properties are due (the urea, lithic acid, &c.), the Malpighian bodies might be an apparatus destined to separate from the blood the watery portion. This view, on further consideration, appears so consonant with facts, and with analogy, that I shall in a few words state the reasons that have induced me to adopt it. I am not unaware how obscure are the regions of hypothesis in physiology, and shall be most ready to renounce my opinion, if it be shown to be inconsistent with truth.\n\u201c In extent of surface, internal structure, and the nature of its vascular network, the membrane of the uriniferous tubes corresponds wdth that forming the secreting surface of other glands. Hence it seems certain that this membrane is the part specially concerned in eliminating from the blood the peculiar principles found in the urine. To establish this analogy, and the conclusion deduced from it, a few words will suffice. 1. The extent of surface obtained by the involutions of this membrane will by most be regarded as itself sufficient proof. But, 2. Its internal surface is conclusive. Since epithelium has been found by Purkinje and Henle in such enormous quantities on the secreting surface of all true glands, its use cannot be considered doubtful. It never forms less than ^fths of the thickness of the secreting membrane, and in the liver it even seems to compose it entirely, for there 1 have searched in vain for a basement tissue, like that which supports the epithelium in other glands. The epithelium, thus chiefly forming the substance of secreting membrane, differs in its general characters from other forms of this structure. Its nucleated particles are more bulky, and appear from their refractive properties to contain more substance, their internal tissue being very finely mottled, when seen by transmitted light. In these particulars the epithelium of the kidney-tubes is eminently allied to the best-marked examples of glandular epithelium. 3. The capillary network surrounding the uriniferous tubes is the counterpart of that investing the tubes of the testis, allowance being made for the difference in the capacity of these canals in the two glands. It corresponds with that of all true glands in lying on the deep surface of the secreting membrane, and in its numerous vessels everywhere anastomosing freely with one another.\n\u201c These several points of identity may seem too obvious to be dwelt upon, but I have detailed them in order to show that in all","page":254},{"file":"p0255.txt","language":"en","ocr_en":"REN.\nthese respects the Malpighian bodies differ from the secreting parts of true glands. 1. The Malpighian bodies comprise but a small part of the inner surface of the kidney, there being but one to each tortuous tube. 2. The epithelium immediately changes its characters, as the tube expands to embrace the tuft of vessels. From being opaque and minutely mottled, it becomes transparent, and assumes a definite outline ; from being bald, it becomes covered with cilia (at least in reptiles, and probably in all classes) ; and in many cases it appears to cease entirely a short way within the neck of the Malpighian capsule. 3. The blood-vessels, instead of being on the deep surface of the membrane, pass through it and form a tuft on its free surface. Instead of the free anastomoses elsewhere observed, neighbouring tufts never communicate, and even the branchlets of the same tuft remain quite isolated from one another.\n\u201c Thus the Malpighian bodies are as unlike, as the tubes passing from them are like, the membrane which, in other glands, secerns its several characteristic products from the blood. To these bodies, therefore, some other and distinct function is with the highest probability to be attributed.\n\u201c When the Malpighian bodies were considered merely as convoluted vessels, without any connection with the uriniferous tubes, no other office could be assigned them than that of delaying the blood in its course to the capillaries of the tubes, and the object of this it was impossible to ascertain. Now, however, that it is proved that each one is situated at the remotest extremity of a tube, that the tufts of vessels are a distinct system of capillaries inserted into the interior of the tube, surrounded by a capsule formed by its membrane, and closed everywhere except at the orifice of the tube, it is evident that conjectures on their use may be framed with greater plausibility.\n\u201c The peculiar arrangement of the vessels in the Malpighian tufts is clearly designed to produce a retardation in the flow of the blood through them ; and the insertion of the tuft into the extremity of the tube, is a plain indication that this delay is subservient in a direct manner to some part of the secretive process.\n\u201c It now becomes interesting to inquire, in what respect the secretion of the kidney differs from that of all other glands, that so anomalous an apparatus should be appended to its secerning tubes. The difference seems obviously to lie in the quantity of aqueous particles contained in it ; for how peculiar soever to the kidney the proximate principles of the urine may be, they are not more so than those of other glands to the organs which furnish them.\n\u201c This abundance of water is apparently intended to serve chiefly as a menstruum for the proximate principles and salts which this secretion contains, and which, speaking generally, are far less soluble than those of any other animal product. This is so true, that it is .common for healthy urine to deposit\n255\nsome part of its dissolved contents on cool-ing.\n\u201c If this view of the share taken by the water be correct, we must suppose that fluid to be separated either at any point of the secreting surface along with the proximate principles, as has hitherto been imagined, or else in such a situation that it may at once freely irrigate the whole extent of the secerning membrane. Analogy lends no countenance to the former supposition ; while to the latter, the singular position and all the details of the structure of the Malpighian bodies, give strong credibility.\n\u201c It would indeed be difficult to conceive a disposition of parts more calculated to favour the escape of water from the blood than that of the Malpighian body. A large artery breaks up in a very direct manner into a number of minute branches, each of which suddenly opens into an assemblage of vessels of far greater aggregate capacity than itself, and from which there is but one narrow exit. Hence must arise a very abrupt retardation in the velocity of the current of blood. The vessels in which this delay occurs are uncovered by any structure.* They lie bare in a cell from which there is but one outlet, the orifice of the tube. This orifice is encircled by cilia in active motion, directing a current towards the tube. These exquisite organs must not only serve to carry forward the fluid already in the cell, and in which the vascular tuft is bathed, but must tend to remove pressure from the free surface of the vessels, and so to encourage the escape of their more fluid contents. Why is so wonderful an apparatus placed at the extremity of each uriniferous tube, if not to furnish water to aid in the separation and solution of the urinous products from the epithelium of the tube?\u201d\nThere is nothing which appears to afford greater support to Mr. Bowman\u2019s theory than the structure of the kidney of the boa, when considered in connexion with the fact that the urine in this animal is excreted in an almost solid form. It will be rememberedj' that the greater part of the blood supplied to the kidney of the boa is derived from a vein which comes from the posterior part of the body ; this vein forms the plexus which surrounds the uriniferous tubes, and from which, according to Mr, Bowman, the solids of the urine are excreted. The renal artery, which is comparatively of small size, is distributed to the Malpighian bodies, as in the higher animals, and the efferent vessel joins the portal vein. The solid urine of the serpent seems a necessary consequence of the peculiar distribution of the blood-vessels ; the small Malpighian bodies pour out a scanty stream of water sufficient only to carry through the tubes the large quantities of solid matter which the more numerous and larger vessels distributed on the outer surface of the tubes are continually supplying.\n* With reference to this point, vide ante, p. 248-9.\nf Vide ante, p. 250.","page":255},{"file":"p0256.txt","language":"en","ocr_en":"256\nREN.\nAnother fact confirmatory of Mr. Bowman\u2019s theory has been observed by myself.* In examining the kidneys of persons who had died jaundiced, and in whose urine there had been a large quantity of bile, I observed that the tubes were stained of a deep yellow colour by the bile in their epithelical cells, and that this yellow colour ceased abruptly at the neck of the Malpighian capsule, and in no instance did it affect any part of the tissue of the Malpighian bodies. There are certain other pathological phenomena, which Mr. Bowman\u2019s theory very much assists to explain, and which in their turn afford important evidence in support of the doctrine in question.\nThe office of secreting the solids of the urine is limited to the convoluted portions of the tubes. The straight tubes of the pyramids probably have no secreting power, but act merely as excretory ducts to convey the secreted products from the cortical portion of the gland. The different function of these two portions of the tubes is sufficiently manifested by two facts : \u2014 1st. By the difference in the character of their epithelial lining ; 2dly. By the fact, that when the cortical portion of the kidney is the seat of a morbid deposit in consequence of the attempted excretion of abnormal products by the epithelial cells in the convoluted tubes, the medullary portion of the gland is very commonly free from all trace of the same morbid deposit. This is very frequently observed in instances of fatty degeneration, as well as in the earlier stages of the inflammatory diseases of the kidney.\nPART III.--PATHOLOGY OF THE KIDNEY.\nIt will not be possible within the limits of this article to give more than an outline of the pathology of the kidney. The subject is one of such great interest and importance that it requires a much more extended consideration than can here be assigned to it.\nThe diseases of the kidney may be arranged in two distinct classes: the first class including those which are the result of some cause acting locally, such as retention of the urine in consequence of stricture, the mechanical irritation of a stone impacted in the kidney, or a blow on the loins; while in the second class are included those diseases which are the result of a constitutional cause which acts upon the kidney by inducing an abnormal condition of the blood.\nWe shall allude very briefly to the first class of diseases, and then proceed to the consideration of those diseases to which the kidney is liable in consequence of a deteriorated condition of the blood.\nDisease of the kidney from retention of urine. \u2014Fig. 165. represents a condition of the kidney which commonly results from an impeded escape of the urine. The ureter pelvis and infundibula become much dilated, and the cortical substance expanded and lobular on the surface, the depressions between the\n* Med. Chir. Trans, vol. xxx.\nlobules resulting from the binding down of the tissue by the interlobular septa, in the\nFig. 165.\nSection of the kidney from a patient who had stricture. The pelvis and infundibula are much dilated, the cortical portion is expanded, and its surface lobular. The parts are reduced about one third in the drawing.\nintervals of which the glandular structure is protruded by the distending force from within. The mucous membrane frequently becomes ulcerated, inflammatory deposits occur in the substance of the kidney, and so the gland is destroyed by a slow atrophy, or more rapidly by suppurative inflammation. Both kidneys are usually affected, but in different degrees. On a microscopical examination of the kidney thus diseased, pus and other inflammatory deposits are found. The deposits are not confined to the tubes, but they occur irregularly throughout the gland, so as in many instances to obliterate all appearance of tubular structure.\nDisease of the kidney from renal calculi. \u2014 When a calculus forms in the kidney, it may lead to very different results according to its size and position. If of small size, it may pass down the ureter and so get into the bladder; or if it be too large to pass through the ureter, it may, by becoming impacted in the canal, and so obstructing the flow of urine, give rise to a rapidly destructive suppurative inflammation, or it may lead to complete atrophy of the gland. It sometimes happens that several calculi become impacted in the pelvis of one or both kidneys, causing ulceration of the surrounding tissue, and leading in some instances to a complete disorganisation of the gland.","page":256},{"file":"p0257.txt","language":"en","ocr_en":"REN.\n257\nDisease of the kidney from external violence\u2014 is not of common occurrence. One case of the kind has occurred to myself. A strong man in robust health received a violent blow on the loins from a bludgeon ; he suffered much pain, and within a short time after the receipt of the injury he had h\u00e6maturia. The bleeding recurred at intervals during several months, and was succeeded by a discharge of purulent matter with the urine. The purulent discharge continued for a period of more than a year, when the poor man died much emaciated. On a post mortem examination, the right kidney was found completely destroyed by suppurative inflammation ; there was no strumous deposit in the kidney or in any other organ. There was no calculus. The left kidney was quite sound.\nExtension of disease from other organs to the kidney. \u2014 The kidney sometimes becomes involved in malignant or other disease affecting the intestines and other adjacent viscera. Allusion has already been made to a preparation in the Museum of King\u2019s College, in which there is a communication between an abscess in the psoas muscle and the canal of the ureter.\nDiseases resulting from a constitutional cause. \u2014Scrofulous disease of the kidney occurs in the form of small scattered deposits of tubercular matter, or it presents itself in the form of a thick curdy deposit which leads to the formation of a large scrofulous abscess, the cavity of which is subdivided by septa formed by the thickened interlobular cellular tissue. (Jig. 166.) The scrofulous deposit commonly\nFig, 166.\nScrofulous abscess in the kidney. The cavity of the abscess is divided by septa, which are formed by the interlobular cellular tissue, thickened by an interstitial deposit of strumous matter. The glandular structure has been destroyed by suppurative inflammation.\nextends over the mucous membrane of the ureter, which becomes much thickened.\nAcute suppurative nephritis is not a common disease, but it is a very serious and a very fatal one. In one case it supervened upon\nVOL. IV.\nchronic disease of the kidney, in consequence of the intemperate use of fermented liquors by a man whose general health was much disordered, and who had been subject for several months to successive crops of boils and carbuncles about the neck and shoulders. He died in about a week after symptoms of suppurative nephritis had manifested themselves. The nature of the disease was detected at the very commencement by a microscopical examination of the urine (\u00dfg.l&l). Both kidneys\nFig. 167,\nDeposit in the urine of a patient labouring under acute suppurative nephritis, a, crystals of triple phosphate ; b, c, d, moulds from the tubes of the kidney, the last entangling pus corpuscles. Some free pus corpuscles are scattered about the field. Magnified 200 diameters.\nwere much enlarged, evidently from a recent attack of acute inflammation, numerous small points of suppuration were scattered through them, and the left contained two large recent abscesses. This case occurred in King\u2019s College Hospital, under the care of Dr. Todd.\nAcute desquamative nephritis.\u2014This form of disease occurs very frequently as a consequence of scarlatina, and is occasionally produced by other animal poisons, as for instance that of typhus fever, small-pox, or measles. The same condition of kidney very commonly occurs amongst the poor in large towns and elsewhere, as a consequence of that deteriorated condition of the blood, which results from an insufficient supply of animal food ; and it sometimes occurs as a consequence probably of a similarly deteriorated condition of the blood in persons who are much reduced by long-continued disease, as for instance secondary syphilis or chronic abscess.\nThe kidney in these cases is enlarged, apparently by the deposit of a white material in the cortical substance ; the vessels in the cortical portion where they are not compressed by this new material, are injected, and of a bright red hue ; the medullary cones are of a dark red colour, in consequence of the large veins which occupy these portions of the gland being distended with blood. The ap-\ns","page":257},{"file":"p0258.txt","language":"en","ocr_en":"258\nREN.\npearance of the entire organ is quite that of a part in a state of acute inflammation.\nWhen the kidney has been in a softened condition before the occurrence of the inflammatory disease, as often happens in elderly persons, the lobules on the surface appear larger and coarser than natural ; the veins being less^ compressed than when the natural texture of the kidney is firmer and more unyielding, are much distended with blood, so that the entire organ is of a dark slate colour.\nOn a microscopical examination the convoluted tubes are seen filled, in different degrees, with nucleated cells, differing in no essential character from those which line the tubes of the healthy gland (fig. 168). The\nFig. 168.\nSection of a portion of inflamed kidney. The tubes appear as if divided into distinct globular and oval portions ; this appearance results from the manner in which the tubes are packed in the meshes of the fibrous matrix, so as to he concealed where they are crossed by the fibrous tissue, and visible in the intervals. The tubes are rendered opaque by an accumulation of epithelium, the outline of the cells being invisible on account of their being closely packed. A Malpighian body in the centre of the mass appears transparent and healthy. Magnified 200 diameters. Med. Chir. Trans, vol. xxx.\nMalpighian bodies are for the most part transparent and healthy, but the vessels of the tuft are sometimes rendered opaque by an accumulation of small cells on their surface. Some of the tubes contain blood, which has doubtless escaped from the gorged Malpighian vessels. There is no deposit exterior to the tubes.\nThe condition of the urine in these cases is clearly indicative of the process going on in the kidney. After it has been allowed to stand for a short time, a sediment forms ; and on placing a portion of this under the microscope, there may be seen blood-corpuscles, with epithelial cells in great numbers, partly free and partly entangled in cylindrical fibrinous casts of the urinary tubes*, and very commonly numerous crystals of lithic acid are present (fig. 169).\nAs the disease subsides, which under proper treatment it usually does in a few days, the blood, fibrinous casts, and epithelial cells di-\n* The fibrinous moulds of the kidney tubes, as seen in albuminous urine, were first observed by the late Dr. F. Simon of Berlin.\nminish in quantity, and finally disappear ; but traces of the casts may be seen some days after the urine has ceased to coagulate, on the application of heat or nitric acid.\nFig. 169.\nPortion of a tube much dilated and divided by septa which correspond with the rings of fibrous tissue in the microscopic specimen. See fig. 149, b.\nThe cluster about b includes two fibrinous moulds of the urinary tubes, entangling epithelial cells and blood corpuscles, two free epithelial cells, and three crystals of lithic acid from the urine in a case of \u201c acute desquamative nephritis.\u201d\nc,\tA mass of oily matter from the urine.\nd,\tA cluster of octohedral crystals of oxalate of lime.\nMagnified 200 diameters. Med. Chir. Trans, vol.\nXXX.\nThe changes above described as occurring in the kidney are the result of a modification of the natural process of secretion produced by the presence of abnormal products in the blood. These products are eliminated by an excessive development of epithelial cells which are thrown into the tubes and washed out with the urine. The desquamation from the inner surface of the tubes is analogous to that which occurs on the skin subsequent to the eruption of scarlatina. I have, therefore, proposed to apply the term \u201c acute desquamative nephritis\u201d to this form of disease.*\nChronic desquamative nephritis is essentially of the same nature as the acute form of the disease. Its most frequent cause is the gouty diathesis, and it very rarely occurs except in those who are addicted to the use of alcoholic drinks.-f- In the earlier stage of the disease the kidney is of the natural size, or very slightly enlarged, and the structure of the organ appears confused, as if from the admixture of some abnormal product; there is\n* See the author\u2019s paper on this subject in the a Med. Chir. Trans, vol. xxx.\nf This form of diseased kidney was first described by Dr. Todd, under the name of gouty kidney, in a ; clinical lecture which was delivered in June 1846,\t,<\nand published in the Medical Gazette for June 1847.\t.'\nIn this lecture Dr. Todd alludes particularly to the \u00bb destruction of the secreting cells, and the consequent ii deficient excretion of the solid constituents of the oi urine.\n<","page":258},{"file":"p0259.txt","language":"en","ocr_en":"REN.\n259\nalso some increase of vascularity. As the disease advances, the cortical portion gradually wastes, and the entire organ becomes contracted, firm, and granular, the medullary cones remaining comparatively unaffected even in the most advanced stages ; simultaneously with the diminution in the size of the kidney there is a decrease of vascularity. These changes occur very gradually ; the disease having a duration in most cases of many months, and in some even of several years.\nOn placing thin sections of the kidney under the microscope, some of the tubes are seen to be in precisely the same condition as in a case of acute desquamative nephritis : they are filled and rendered opaque by an accumulation within them of nucleated cells, differing in no essential respect from the normal epithelium of the kidney. This increase in the number, and this slight alteration in the character of the epithelial cells are the result of the elimination by the kidney of mal-assi-milated products, which are being continually developed in gouty and intemperate subjects, and which are not normal constituents of the renal secretion.\nThere would evidently be a certain limit to the number of cells which can be formed in any one of the uriniferous tubes ; for although some of the cells escape with the liquid part of the secretion, and so may be seen in the urine, as in a case of acute desquamative nephritis, yet in many of the tubes the cells become so closely packed that the further formation of cells becomes impossible, and the process of cell-formation, and consequently of secretion within these tubes, is arrested. The cells, thus formed and filling up the tube, gradually decay and becomes more or less disintegrated. While these changes are occurring in the tubes, the Malpighian bodies frequently continue quite healthy, their capsules for the most part transparent, and the vessels in their interior perfect. From these vessels water, with some aibumen and coagulable matter, is continually being poured into the tubes ; and, as a consequence of this, the disintegrated epithelial cells are washed out by the current of liquid flowing through the tubes, so that, on ex-\njFig. 170.\nCasts of the urinary tubes, composed of fibrinous matter and disintegrated epithelium from the urine, in a case of chronic desquamative nephritis. Magnified 200 diameters. Med. Chir. Trans, vol. xxx.\namining the sedimentary portion of the urine, we find in it cylindrical moulds of the urinary tubes, composed of epithelium in different degrees of disintegration, and rendered coherent by the fibrinous matter which coagulates amongst its particles. ( fig. 170.)\nThere is reason to believe that when the process of cell-development and of secretion have once been arrested by a tube becoming filled with its accumulated contents, the tube never recovers its lining of normal epithelial cells ; but when the disintegrated epithelium has been washed away from the interior of the tube, the basement membrane may be seen in some cases entirely denuded of epithelium ; in other tubes a few granular particles of the old and decayed epithelium remain (fig. 171.) ;\nFig. 171.\nSection of a portion of kidney, showing the tubes deprived of their epithelium by \u201c chronic desquamative nephritis.\u201d The tubes as they lie packed in the meshes of the fibrous matrix have an appearance somewhat like that of globular and oval transparent vesicles or cysts. See/ros. 149 c and 150. Magnified 200 diameters. Med. Chir. Trans, vol. xxx.\nand again, in other instances, the interior of a tube which has been deprived of its proper glandular epithelium is seen lined by small delicate transparent nucleated cells (Jig. 172.),\nFig. 172.\na, Section of a portion of kidney showing the tubes lined by delicate transparent nucleated cells ; these cells have taken the place of the normal epithelium which has been destroyed and swept away ; b, portion of the basement membrane of a tube deprived of its epithelium, and contracted by its elasticity into an irregular globular form after being detached from the surrounding tissues ; c, portion of a tube much dilated, and bulging in the intervals of the matrix ; the constricted portions correspond with the surrounding rings of fibrous tissue. Magnified 200 diameters. Med. Chir. Trans, vol. xxx.\ns 2","page":259},{"file":"p0260.txt","language":"en","ocr_en":"REN.\n260\nvery similar to those which may sometimes be seen covering the vessels of the Malpighian tuft. ( Vide ante, fig. 160.)\nAfter the tubes have lost their normal epithelial lining they may undergo one of the three following changes. 1. In some instances a peculiar whitish glistening material is thrown into the tubes, some of which escapes with the urine in the form of cylindrical moulds of the tubes, the appearance of which as seen in the urine is somewhat imperfectly represented in fig. 173. The effect\nFig. 173.\nCylindrical moulds of the urinary tubes composed of a peculiar whitish glistening material, which is sometimes effused into the tubes in the advanced stages of chronic nephritis. From the urine. Magnified 200 diameters.\nof this material being effused into the tubes appears to be to obliterate them, and in some instances it apparently becomes organised into fibrous tissue.\n2.\tAnother change which the tubes undergo in consequence of losing their epithelial lining, is that of becoming atrophied. The power of separating the solid urinary constituents from the blood resides in the epithelial cells which line the convoluted tubes. After the destruction of the cells the secreting power is lost, and as the normal action of the cells is certainly one of the essential conditions for maintaining the continued flow of blood to the tubes, so the removal of the cells is very commonly followed by a diminished afflux of blood, and a consequent wasting of the tubes.\n3.\tAnother change consequent upon the destruction of the epithelial cells is, in a certain sense, the reverse of the preceding. The tubes appear to retain the power of secreting serum, which fills and dilates the tube in consequence of its escape being prevented by epithelial debris choking up the lower extremity of the tube. When once a tube is brought into this condition the process of dilatation may proceed to an almost unlimited extent. The tube bulges in the intervals of the fibrous matrix, and assumes the appearance represented in fig. 172 c. These dilated\ntubes form the serous cysts which are so commonly seen in the cortical portion of the kidney. And it is remarkable that the moni-liform appearance of the dilated tubes, as seen in the microscopic specimens, is in many instances preserved even when the tube is so much dilated as to form cysts visible to the naked eye. (Fig. 174.)\nFig. 174.\nSectiqn of a portion of kidney in which, serous cysts have been developed. At a there is a series of four cysts which are probably formed by the dilatation of a single tube. Compare this withy?*/. 172. From a specimen in the museum of King\u2019s College. Natural size.\nMr. Simon, in a paper on \u201c Subacute Inflammation of the Kidney,\u201d* has propounded the theory that these cysts are greatly dilated epithelial germs, which become thus monstrously developed in consequence of the destruction of the basement membrane of the tubes.\nIf Mr. Simon\u2019s account of these cysts were correct they would be in fact hydatid cysts. I am not prepared to deny that cysts are ever formed in the kidney by the development of isolated cells, as described by Mr. Simon ; it is very possible that such an occurrence may be not unfrequent, although it has hitherto escaped my observation. But there can, I think, be no doubt in the mind of any one who will carefully examine the subject, that the appearances described and figured by Mr. Simon are produced simply by the packing of the tubes in the fibrous network which surrounds and partially conceals them. The best safeguard against a misinterpretation of appearances in diseased specimens is a careful study of the healthy tissues. The peculiar cyst-like appearance of the tubes in cases of chronic nephritis results from the transparency of the tubes when deprived of their epithelial lining. This delicate and\n* Med. Chir. Trans, vol. xxx.\ni","page":260},{"file":"p0261.txt","language":"en","ocr_en":"261\nREN.\ntransparent appearance of the tubes, which in the human kidney is the result of disease, may constantly be seen in the kidneys of some of the smaller animals ; as, for example, those of a mouse or a young rabbit. On examining thin sections of the kidneys of these animals it will be found that the delicate and semitransparent tubes, embedded in the surrounding fibrous network, constantly present more or less of the cyst-like appearance represented in fig. 171. It can scarcely be supposed that these appearances in the kidney of the mouse indicate the existence of isolated cells. In short, Mr. Simon\u2019s theory of renal cysts is so opposed to all analogy, and so entirely unsupported by facts, that it appears needless to occupy the time of our readers by a further detail of facts and arguments in opposition to it.\nRenal H\u0153morrhage. \u2014 Under this head I will allude in a few words to a condition of kidney which I have never had an opportunity of examining in the dead subject, but the nature of which is sufficiently manifested by the symptoms, and particularly by the condition of the urine, as ascertained by a microscopical examination during life. It is well known that great irritation of the urinary organs is a frequent consequence of the inter* nal administration of oil of turpentine, or the application of cantharides to the cutaneous surface. The urine in these cases is generally bloody, and is passed very frequently and in small quantities ; there is great pain and irritation about the kidneys and bladder ; but there are no symptoms of suppression of urine, such as drowsiness and tendency to inflammation of internal organs, symptoms which are present, in a greater or less degree, in all cases of \u201c desquamative nephritis.\u201d In the last-mentioned cases the epithelial lining of the urinary tubes is the seat of disease, and the imperfect elimination of the solid constituents of the urine is a necessary consequence of the pathological changes which the secreting epithelium undergoes. In the condition of kidney now under consideration the Malpighian capillaries appear to be the only parts of the organ primarily affected. The irritation produced by the turpentine or the cantharides leads to engorgement of the Malpighian tufts, which commonly ends in rupture of the vessels, haemorrhage into the tubes, and so the admixture of blood with the urine. On a microscopical examination of the urine fibrinous moulds of the tubes may be seen in great numbers (fig. 175), blood corpuscles are entangled in the fibrine, but no epithelium is found combined with them. The inference is, that the epithelial lining, of the urinary tubules is unaffected, and this conclusion is further supported by the fact already mentioned, viz., the absence of the usual symptoms resulting from a deficient excretion of urea and the other solid constituents of the urine. I have never seen a fatal case of strangury ; but when haemorrhage from the Malpighian capillaries has occurred in connection with other pathological conditions\nwhich have terminated fatally, haemorrhagic spots are seen scattered over the surtace ana through the cortical substance of the kidney.\nFig. 175.\nFibrinous moulds of the urinary tubules from the urine of a patient who had strangury after taking oil of turpentine. Some blood corpuscles are entangled in the fibrine, as well as some octohedral crystals of oxalate of lime which the patient was excreting at the time the haemorrhage occurred. . It is important to observe that in this form of fibrinous mould there is no epithelium from the tubes. Magnified 200 diameters.\nThese spots, when submitted to a microscopical examination, are found to be composed of convoluted tubes filled with blood which has escaped from the Malpighian capillaries, and after filling the capsule has passed into the tube (fig. 176). This fact was first pointed out by Mr. Bowman.\nFig. 176.\nMalpighian capsule and portions of the urinary tubes containing blood which has escaped from the Malpighian capillaries. Magnified 200 diameters. See also fig. 149 d.\nThe condition of kidney to which turpentine and cantharides give rise may result from\ns 3","page":261},{"file":"p0262.txt","language":"en","ocr_en":"262\nREN.\nthe irritation produced by certain products developed within the body. I have met with two well marked cases of this kind, in which the characters of the urine, as revealed by a microscopical examination, and the other attendant symptoms were the same. In both cases the symptoms were of short duration. When the blood in cases of h\u00e6maturia is found to be moulded in the urinary tubes, there can of course be no doubt as to the haemorrhage being renal. During the first few hours of an attack of h\u00e6maturia it commonly happens that the blood escapes from the kidney before it has coagulated, and at this period of the attack a large quantity of the blood will be found not to have the form of cylindrical moulds when examined by the microscope, but even in this case a careful examination will always detect some moulds, and that will suffice for the diagnosis; and at a later period of the attack, when the h\u00e6mor-rhage occurs more slowly it will be found that nearly all the blood has been moulded into the urinary tubes before it has escaped from the kidney. When renal haemorrhage is produced by the irritation of a calculus impacted in the pelvis or the ureter, the blood does not present the fibrinous moulds in question.\nFatty degeneration of the kidney occurs under two distinct forms. In the first form of the disease in question, the kidneys are usually large, smooth, soft, pale, and mottled, and frequently they are scattered over with h\u00e6morrhagic spots. On a microscopical examination, there is found to be a great increase in the size and number of the oil globules which exist in small quantities in the epithelial cells of the healthy gland. (See fig. 164.) The urinary tubes are filled and distended by the gorged epithelial cells, the dilated tubes compress the capillary plexus on their exterior, and hence, in consequence of passive congestion of the Malpighian vessels, the serum of the blood gets mixed with the urine, which thus becomes albuminous ; and when the obstruction of the circulation is still greater the colouring matter of the blood escapes from the delicate Malpighian vessels and fills the tubes, giving rise to the h\u00e6morrhagic spots before mentioned.\nIt is only that form of epithelium whose office it is to excrete the solid portion of the urine which becomes gorged with oil ; the delicate epithelium covering the Malpighian vessels, as well as that which lines the straight tubes of the medullary cones, retains its normal condition : the reason of these parts remaining healthy while the epithelium of the convoluted tubes becomes greatly changed, as well in cases of fatty degeneration of the kidney as 'in the desquamative inflammatory diseases before alluded to, will be manifest from a perusal of the second part of this article.\nIn this form of simple fatty degeneration of the kidney, all the tubes become almost uniformly distended with oil. In a slight degree, and in the earlier stages, it is often found after death in cases where there is\nno reason to suspect that it has been productive of serious mischief during life : it is not until the fatty degeneration exceeds a certain degree that the functions of the organ become seriously affected. It is this form of fatty degeneration which frequently occurs in animals, as a consequence of their confinement in a dark room, a fact which was first noticed by Mr. Simon*\nThe second form of fatty degeneration of the kidney differs from the first in having combined with it more or less of the changes characteristic of desquamative nephritis. The cortical portion of the kidney is soft and pale, and interspersed with numerous small yellow opaque specks. The kidney is generally enlarged ; sometimes it is even double the natural size. In some cases the cortical portion is somewhat atrophied and granular; but neither in this nor in the first form of fatty degeneration of the kidney does that extreme wasting with granulation occur, which is so frequent a consequence of chronic nephritis.\nOn a microscopical examination the convoluted tubes are found filled in different degrees with oil, some tubes being quite free, while others are ruptured by the great accumulation in their interior. The opaque yellow spots scattered throughout the cortical portion are neither more nor less than convoluted tubes distended, and many of them ruptured by their accumulated fatty contents. The cells which contain the oil are for the most part smaller, more transparent, and less irregular in their outline than the ordinary healthy epithelium ; they are increased in number, and many of them are so distended with oil as to appear quite black. In parts of the same kidney there may commonly be seen some of the appearances already described as characteristic of desquamative nephritis. This form of disease is very commonly associated with fatty degeneration of the liver, but less frequently so than the first form of fatty degeneration of the kidney.\nThe condition of urine connected with this form of renal degeneration is usually as follows :\u2014 The quantity is small, the sp. gr. rather above than below the healthy standard ; it is generally very albuminous, and sometimes bloody. On a microscopical examination of the sediment which is deposited after standing for a few hours in a conical glass, there may be seen the fibrinous moulds of the tubes so often alluded to, frequently entangling blood corpuscles and epithelium. But the main point to be attended to is this, that many of the epithelial cells are more or less distended with oil. (See figs. 149 and 164.)\nThis fatty condition of the epithelium indicates with certainty the existence of one of the most serious and intractable diseases to which the kidney is liable. The majority of 1( the cases of acute desquamative nephritis, and many of the chronic cases, end in complete recovery; but fatty degeneration of the kidney almost invariably leads to general dropsy and\n* Med. Chir. Trans, vol. xxix.","page":262},{"file":"p0263.txt","language":"en","ocr_en":"KEN.\na fatal termination. It is therefore as important to distinguish between acute or chronic nephritis and fatty degeneration of the kidney as it is to distinguish acute pneumonia or chronic bronchitis from tubercular disease of the lung ; and the diagnosis of the renal disease may be made with as much ease and certainty by a microscopical examination of the urine as that of the pulmonary disease by auscultation and percussion of the chest.\nThe three forms of disease just alluded to, viz. acute and chronic desquamative nephritis, and fatty degeneration of the kidney, include the greater number of those cases to which the term \u201c Bright\u2019s disease\u201d is commonly applied.\nOn an inspection of the plates in the 1st vol. of Dr. Bright\u2019s well known Medical Reports, it is evident that more than one form of disease is there described by that distinguished physician. In a paper published two years since*, I maintained that the term Bright\u2019s disease should be confined to those cases in which there is fatty degeneration of the kidney, but after a further consideration of the subject, I am of opinion that if the expression \u201c Bright\u2019s disease\u201d is retained it should be used only as a generic term to include several diseases, the existence and the importance of which were first made known by Dr. Bright. In order to convey a precise idea of the particular form of Bright\u2019s disease alluded to, it is clearly necessary to use some terms having a more definite meaning, and I have suggested some which appear sufficiently expressive for the purpose.\nHydatids are occasionally found in the kidney. Dr. Baillief was well aware of the distinction between true hydatid cysts as they are found in the kidney and the more common serous cysts, which he correctly supposed to arise from an expansion of some of the natural tissues of the kidney. He mentions one case of hydatids in the kidney, in which there was a discharge of these bodes with the urine. It is probable that in every case of hydatid disease of the kidney, the nature of the affection might be ascertained by a careful examination of the urine. I have already stated that if Mr. Simon\u2019s account of the common serous cysts were a correct one, they would be in fact hydatid cysts, and as they would continually escape with the urine, they might be detected by a microscopical examination of the liquid. Assuming, however, that they are dilatations of the tubes, it is not surprising that they should never be found in the urine, and that they cannot be dissected out from the kidney after death.\nCancer of the kidney is less uncommon than it was formerly supposed to be. It is rarely limited to the kidney, and in the great majority of cases, where other parts are implicated, the disease has obviously originated in some one or other of these parts. J Can-\n* Med. Chir. Trans, vol. xxix.\n\u2022j- The Morbid Anatomy of the Human Body. By Matthew Baillie, M.D.\nt The Nature and Treatment of Cancer. By Walter Hayle Walshe, M.D.\n263\ncer less frequently affects the bladder and kidney simultaneously than might be expected. M. Rayer and Dr. Walshe have observed the frequent co-existence of cancer of the liver and right kidney, and of the adjacent parts of the stomach on the descending colon and the left kidney.\nIn thirty-six of the cases collected by Dr. Walshe, the anatomical state is described with considerable accuracy. \u201c In thirty-one of these, pure encephaloid or one of its va-rities, was the species of cancer observed ; scirrhus in five only, \u2014 two of them of doubtful character; while colloid did not, in any instance, occur in this situation. Encephaloid exhibits itself in all degrees of consistence, and in several of its varieties. Among these varieties, the h\u00e6matoid may almost be considered frequent, as compared with ks rarity in other internal organs. Encephaloid occurs in the infiltrated and tuberous forms ; the former more especially when the disease is primary, the latter when secondary. Cancerous infiltration (as organic diseases generally) commences in the cortical substance. This structure may, in some instances, disappear altogether under the influence of the accumulating cancerous matter, without the tubular substances having suffered in the least. The nodular form of the affection likewise originates in the cortical substance, generally near the surface ; as the masses enlarge,they become prominent on the surface, and assume the appearance of having formed between the surface of the kidney and its capsule.\u201d The renal tissue between the cancerous masses is sometimes quite healthy ; but in other instances it is congested, inflamed, or actually in a state of suppuration, the pus being infiltrated or accumulated in a single spot. Melanotic discolouration of the cancerous masses is occasionally, but rarely, witnessed in the kidney. In thirty-five cases of renal cancer, the disease affected both organs sixteen times ; the right alone thirteen times, the left alone six.*\nIn concluding this brief sketch of the pathology of the kidney, I will venture to predict that, within a very short space of time, the diseases of the kidney will be more completely and generally understood with reference to their pathology, diagnosis and treatment than those of any other organ. There are two circumstances which justify such an anticipation :\u20141. There is perhaps no important organ in the body whose minute structure has been so completely and so clearly demonstrated as that of the kidney has been by Mr. Bowman. And 2nd, The morbid deposits or accumulations to which the kidney is liable occur, almost without exception, in such a situation, within the uriniferous tubes, that portions of these materials are being continually washed out by the stream of liquid which is poured into the extremities of the tubes, and so they come within the sphere of our daily obser-\n* Dr. Walshe. Op. cit.\ns 4","page":263},{"file":"p0264.txt","language":"en","ocr_en":"264\nREPTIUA.\nvation ; thus affording the pathologist and the practitioner an opportunity of ascertaining the nature and tracing the progress of disease which is not presented in the case of any other internal organ.\nBibliography.\u2014Normal, Anatomy and Physiology.\u2014Bellini, Excercit. Anat. de Structura Renum, Florence, 1662, Leyden, 1711. Albinus, Dissertatio de Poris, 1635. Malpighi, Opera Omnia, Lugd. Bat. 1637. Ruysch, Opera Omnia, Amsterdam, 1700. Ruysch, Opera Omnia, Amsterdam, 1733. Boerhaave, Institut. Med., Lugd. Bat. 1721. Bertin, M\u00e9moires de l\u2019Acad. des Sciences de Paris, 1744. Ferrein, M\u00e9moires de l\u2019Acad. des Sciences de Paris, 1749. Haller, Elementa Physiologies Corporis Humani, Lausann\u00e6, 1757. Schumlansky, De Structura Renum, Argentor, 1788. Eysenhardt, Diss. de Structura Renum Observ. Mic., Berlin, 1818. Meckel, Menschliche Anatomie, Halle and Berlin, 1820. Jacobson, Isis, 1822, and Edinb. Med. and Surg. Journal, 1823. Huschke, Isis, 1828. Muller, De Glandu-larum Secernentium Structura, Leipzig, 1832. Laurent, De la Texture et du D\u00e9veloppement de l\u2019Appareil Urinaire. Th\u00e8se de Concours, Paris, 1836. Berres. Anatomie der Mikroscopischen Gebilde, Vienne, 1837. Krause, a Muller\u2019s Archiv., 1837 ; b Handbuch der Anatomie, Hanover, 1848. Henle, Muller\u2019s Archiv., 1838. Cayla, Observ. d\u2019Anatomie Micros-cop. sur le Rein des Mammif\u00e8res. Th\u00e8se, Paris, 1839. Ginge, Anatomisch-Mikroscopische Untersuchungen, cah. i. Minden, 1839. Wagner Physiologie, Leip. 1839 : Eng., by Dr. Willis, 1844. Gerber, Handbuch der Allgemeinen Anatomie, Bern. 1840. Vogel, Gebrauch des Mikroskops, Leipzig, 1841. Henle, Allgemeine Anatomie, Leipzig, 1841. M\u00fcller, Vergleichende Anatomie der Myxinoiden. Berlin. 1841. Bowman, Philosophical Transactions, part i. 1842. Goodsir, Monthly Journal of Medical Science, 1842. Reichert, Muller\u2019s Archiv., 1843. Gruby, Annales des Sciences Natur., vol. xvii. M\u00fcller, Handbuch der Physiologie, 4th ed. Coblence. Owen, Lectures on Comparative Anatomy, vol. i. 1843. Gerlach, Muller\u2019s Archiv., 1845. Bidder, M\u00fcller\u2019s Archiv.,\n1845.\tK\u00f6lliker, Muller\u2019s Archiv., 1845. Toynbee, Medico-Chir. Trans, vol. xxix. 1846. Mandl, Anatomie Microscopique, 1847.\nOn the subject of the Development of the Kidney reference may be made to the article Ovum:.\nPathology. \u2014 In addition to works on the practice of Medicine and on general Pathological Anatomy, the following books and papers may he consulted.\u2014Blackall, Observations on the Nature and Cure of Dropsies, and particularly on the presence of the coagulable part of the Blood in Dropsical Urine, London, 1813 ; 3d edition, 1818. Bright, Reports of Medical Cases, 3 vols. 4to, 1827\u20141831, and papers in the Guy\u2019s Hospital Reports. Rayer, Trait\u00e9 des Maladies des Reins. Prout, On Stomach and Renal Diseases. Christison, On Granular Degeneration of the Kidneys, 1839, and in the Library of Practical Medicine. F. Simon, Handbuch der Medizinischen Chemie, translated by the Sydenham Society. Hecht, De Renibus in Morbo Brightii de-generatis, Berlin, 1839. Gluge, Anatomisch-Mikro-scop-Untersuchungen, Jena, 1841. Vogel, leones Histologic\u00e6 Pathologic\u00e6. Henle, Herde und Pfeuf-fer\u2019s Zeitschrift, 1842. Heller, Archiv, f\u00fcr Physiol, und Pathol. Chemie und Mikrosk. band ii. Scherer, Chemische und Mikroskop. Untersuch., Heidelberg, 1843. Valentin, Repertorium, 1837\u20141838. Can-statt, De Morbo Brightii, Erlangen, 1844. Eichholtz, M\u00fcller\u2019s Archiv., 1845. R. B. Todd, Clinical Lectures on Dropsy with Albuminous Urine, Medical Gazette, 1845 ; and on Gouty Kidney, in Medical Gazette, 1847. Busk, Medic. Chir. Trans, vol. xxix. J. Simon, Med. Chir. Trans, vol. xxx. Malmsten, Ueber die Bright\u2019sche nierenkrankheit, Bremen,\n1846.\tPeacock, Monthly Journal of Medical Science, 1846. G. Johnson, Med. Chir. Trans, vols. xxix.\nand xxx. Reports of the Pathological Society of London, 1847\u20141848. (George Johnson.}\nREPTILIA.\u2014 A very extensive and important class of vertebrate animals, intermediate in their organization and general economy between fishes and the warm-blooded, air-breathing birds and quadrupeds, from both of which reptiles are distinguished by the following characters * : \u2014\nReptiles have the heart disposed in such a manner, that, on each contraction, it sends to the lungs only a portion of the blood which it has received from the various parts of the body, and the rest of that fluid returns to the several parts without having undergone the action of respiration.\nFrom this it results, that the oxygen acts on a less portion of the blood than in the mammifera. If the quantity of respiration in the latter animals, in which the whole of the blood passes through the lungs before returning to the parts, be expressed by unity, the quantity of respiration in the reptiles must be expressed by a fraction of unity.\nIn consequence of this low degree of respiration, reptiles have cold blood, and their muscular power is less than that of quadrupeds, and, \u00e0 fortiori, than that of birds. Accordingly, they do not often perform any movements, but those of creeping and of swimming; and though many of them leap, and run fast enough on some occasions, their general habits are lazy, their digestion slow, their sensations not acute, and in cold and temperate climates they pass almost the entire winter in a state of lethargy. Their muscles preserve their irritability much longer than in the higher classes. Their heart will beat for several hours after it has been plucked out, and its loss does not hinder the body from moving for a long time. In many of them, it has been observed that the cerebellum is remarkably small, which perfectly accords with their little propensity to motion.\nReptiles are provided with a trachea and larynx, though the faculty of an audible voice is not accorded to all of them. Not possessing warm blood, they have no occasion for integuments capable of retaining the heat, and they are covered with scales, or simply with a naked skin.\nThe females have a double ovary, and two oviducts. The males of many genera have a forked or double organ of intromission.\nReptiles do not sit upon their eggs ; hence the latter have generally only a membranous envelope. In many of the reptiles which lay eggs, especially in the colubri, the young one is already formed, and considerably advanced in the egg at the moment when the mother lays it ; and it is the same with those species which may, at pleasure, be rendered viviparous by retarding their laying.\nThe quantity of respiration in reptiles is not fixed, like that of mammifera and birds,\n* Cuvier, R\u00e8gne Animal, t. ii.","page":264},{"file":"p0265.txt","language":"en","ocr_en":"REPTILIA.\n265\nbut varies with the proportion which the diameter of the pulmonary artery bears to that of the aorta. From this proceed differences of energy and sensibility much greater than can exist between one mammiferous animal and another, or one bird and another.\nAccording^, the reptiles exhibit forms, movements, and properties much more various than the two preceding classes ; and it is more especially in their production that nature seems to have sported in the formation of fantastic shapes, and to have modified in all possible ways the general plan which she has followed for vertebrated animals.\nThe comparison of their quantity of respiration and their organs of motion has, however, given foundation for their separation into three distinct orders, viz. : \u2014\n1st, The Chelonians, or Tortoises (Che-lonia), in which the body, supported on four legs, is enveloped by two plates or shields, formed by the ribs and the sternum.\n2d, The Saurians, or Lizards (Sauria), in which the body, supported on four or on two feet, is covered with scales.\n3d, The Ophidians, or Serpents (Ophi-dia), in which the body is always destitute of limbs.\norder i. CHELONIA.\nFamily 1. \u2014 Testudinid\u00e6.\nTestudo (Land Tortoise), Emys (Freshwater Tortoise), Chelonia (Turtle), Chelys, Trionyx.\nORDER II. SAURIA.*\nFamily 1.\u2014 Crocodilid\u00e6.\nGavial, Crocodilus, Alligator.\nFamily 2. \u2014 Lacertid\u00e6.\nMonitor, Crocodilurus, Tupinambis, Ame-iva, Lacerta, Algyra, Tachydromus.\nFamily 3. \u2014 Iguanid\u00e6.\nStellio, Cordylus, Stellio, Doryphorus, Uromas tix, Agama, Agama, Tapayes, Tra-pelus, Leiolepis, Tropidolepis, Leposoma, Calotes, Lophyrus, Gonocephalus, Lyrio-cephalus, Brachylophus, Physignathus, Is-tiurus, Draco, Sitana, Iguana, Ophryessa, Basiliscus, Polychrus, Ecphimotes, Oplu-rus, Anolius.\nFamily 4.\u2014 Geckotid\u00e6.\nGecko, Platydactylus, Hemidactylas, Tkeca-dactylus, Ptyodactylus, Spheriodactylus, Stenodactylus, Gymnodactylus, Phyllurus.\nFamily 5.\u2014 Ciiam\u00e6leonid\u00e6.\nCham\u00e6leo.\nFamily 6. \u2014 Scincid\u00e6.\nScincus, Seps, Bipes, Chalcides, Chirotes.\norder hi. OPHIDIA.f\nFamily 1. \u2014 Anguid\u00e6.\nAnguis, Pseudopus, Ophisaurus, Anguis, Acontias.\n* o-civ\u00e7os, a lizard, f o\u00e7t\u00e7, a serpent.\nFamily 2. \u2014 Serpentid\u00e6.\nAmphisb\u00e6na, Typhlops, Tortrix, Boa Scytalus, Eryx, Erpeton, Coluber, Python, Cerberus, Xenopeltis, Heterodon, Hurria, JDipsas, Dendrophis, Dryinus, Dryophys, Oligodon, Acrochordus, Cro-talus, Trigonocephalus, Vipera, Naia, Elaps, Micrurus, Platurus, Trimeresurus, Oplocephalus, Acanthophis, Eckis, Lan-\u2022 gaha, Bongarus, Hydrus, Hydrophis, Pe-lamides, Chersydrus.\nFamily 3. \u2014 C\u00e6ciliad\u00e6.\nC\u00e6cilia.\nOsteology. \u2014 The Chelonian reptiles are distinguished from all other vertebrata by the peculiar construction of their skeleton ; the bones of the thorax being in these remarkable animals literally placed externally so as to form a suit of armour that encloses the muscles as well as the viscera, and within which the bones both of the shoulder and of the pelvis are lodged. The greater part of the dorsal shield or carapax is formed by eight pairs of ribs (fig. 177, i) united to each other towards the mesial line by a longitudinal series of angular plates, which are in fact the spinous processes (neural spines) of as many vertebrae spread out horizontally. The ribs are connected by suture to the margins of these plates, and likewise to each other, either along their whole length, or to a greater or less extent, according to the species or the age of the animal.\nIn front of the carapax there are eight vertebrae which do not enter into its composition (fig. 177, e) : of these the seven anterior ones, which are ordinary cervical vertebrae, are quite free in their movements. The eighth vertebra, which may be called the first dorsal, is placed obliquely between the last moveable cervical and the first vertebra entering into the composition of the carapax ; posteriorly this vertebra (the eighth) has its spinous process somewhat elongated and slightly enlarged, for the purpose of its attachment by synchondrosis to a tubercle that is situated upon the lower surface of the first of the series of the mesian plates of the carapax.\nThe ribs which, by their external broad plates, enter into the composition of the carapax, give off from their inferior surfaces a process which corresponds with what in ordinary skeletons is called the head of the rib. This process is always connected with the spine between the bodies of two contiguous vertebrae, as are the heads of the ribs in other animals; and, carrying out the comparison, that part of the ribs which articulates by suture with the median plate may be regarded as the \u201c tubercle,\u201d only here it is connected with the expanded spinous process instead of the transverse.\nIn the Turtles the ribs are not united to each other throughout their whole length; towards their external extremities there only remains the narrow central portion, the intervals between the contiguous ribs being in this","page":265},{"file":"p0266.txt","language":"en","ocr_en":"266\nREPTILIA. Fig. 177.\nSkeleton of Tortoise.\nA, superior maxilla ; b, inferior maxilla ; c, ossiculum auditus ; D, os hyoides ; E, cervical vertebr\u00e6 ; F, dorsal vertebr\u00e6 ; G, sacrum ; h, caudal vertebr\u00e6 ; i, dorsal ribs ; K, marginal scales ; N, scapula ; o, coracoid bone ; p, os humeri ; q, radius ; r, ulna ; s, bones of the carpus ; t, metacarpal bones ; u, digital phalanges ; v, pelvis ; w, femur ; x, tibia ; y, fibula ; z, tarsus ; \u00c6, metatarsus ; A.v., phalanges of the foot.\ncase filled up with a cartilaginous membrane. In the carapax of fresh-water tortoises (Emys), and in the Chelides, the interspaces between the ribs in time become completely filled up, and the ribs are connected by suture, throughout their whole extent, to each other and to the marginal pieces (k).\nThe marginal pieces {fig. 177, p) form a sort of osseous frame composed of a series of bones, eleven in number on each side, which are united together by suture, and likewise connected with the extremities of the ribs. In the Tortoises this connection with the ribs is effected by suture, but in the Turtles and other genera having the extremities of the ribs narrow, their apices are implanted in fossae excavated in the marginal plates, where they are fixed by a species of synchondrosis.\nThese marginal plates cannot be otherwise regarded than as the representatives of the sternal ribs of the Crocodiles and other Saurians ; the two first and the two last, like the abdominal ribs of the Crocodile, being developed without the presence of any dorsal ribs in correspondence with them. In the Soft-Tortoises (Trionyx) the marginal pieces are never ossified, but are represented by a cartilaginous rim, in which sometimes osseous particles are sparingly deposited.\nThe ventral cuirass of the Chelonian reptiles, called the plastrum, is exclusively formed by the sternum, which in this race of animals seems to attain its maximum of development. It consists invariably of nine pieces, eight of\nwhich are pairs; while the ninth, situated between the four anterior ones, is central and azygos.\nThese elements of the sternum have been well-named by Geoffroy St. Hilaire in accordance with the situations that they occupy. The anterior pair are the episternal pieces, and the pair situated behind these the hyo-sternals. In the centre bounded by the above four bones is the azygos piece named the ento-sternal. The pair situated immediately posterior to the hyosternal are called the hypo-sternal pieces, and the two which terminate the plastrum xipho-sternals. The sacral and caudal vertebr\u00e6 return to the usual arrangement, being all free and moveable, having their bodies concave in front and convex behind, and their apophyses as in ordinary vertebr\u00e6. Their number varies in different species from eight to twenty-seven.\nThe scapular apparatus is contained in the interior of the thoracic cavity. It consists of a remarkably shaped three-branched bone {fig. 178.), which is suspended on each side by a ligamentous attachment beneath the second vertebra of the carapax. The branch which is thus suspended ( a), notwithstanding its strange position inside the thorax, is the scapula ; the branch b Cuvier, after the ma-turest deliberation, decided to be its acromion process ; while the flattened bone c directed backwards, he considers as being incontestably the coracoid bone. This three-branched shoulder, with its almost cylindrical scapula,","page":266},{"file":"p0267.txt","language":"en","ocr_en":"REPTILIA.\n267\nand an acromion process that almost equals it in size, is quite peculiar to the Chelonian rep-\nFig. 178.\nScapular Apparatus of Chelys. a, scapula ; b, acromion process ; c, coracoid bone.\ntiles, nothing like it existing in any other vertebrate animals : nevertheless, the relations of these bones, and the muscles derived from them, prove clearly enough their identity, and allow of strict comparison with those of other races of vertebrata.\nThe pelvis is always composed of three distinct bones on each side, which contribute, as in quadrupeds, to the formation of the cotyloid cavity, viz. the ilium (fig. 179, a.), which is\nFig. 179.\nPelvis of the Turtle, a, os ilii ; b, os pubis ; c, os iscbii.\nof an elongated form, and attached by ligaments to the transverse processes of the sacral vertebrae, as well as to the neighbouring part of the eighth pair of dilated ribs : secondly, the pubis b, and the ischium c, both of which, expanding as they descend towards\nthe plastrum, terminate by joining their fellows of the opposite side.\nThe cylindrical bones of the extremities resemble those of other four-footed reptiles, and present no peculiarity worthy of special notice, except in a geological point of view.\nIn the turtles, all the bones of the carpus are flattened, and of a squarish form. In the first row there are two bones (fig. 180, c, d.) con-\nFig. 180.\nAnterior extremity of a Turtle. (After Cuvier.')\nnected with the ulna ; and in the second row there are five smaller ones (1, 2, 3, 4, 5.), to which are appended the five metacarpal bones. In addition to the above, there is an intermediate bone (e), situated beneath the ulnar carpal bone (c), and above the second and third bones of the last row, (2, 3.) This piece, Cuvier thinks, corresponds with the dismembered portion of the trapezoid bone, met with in monkeys. Lastly, there is a great crescentshaped bone (/), which is adherent to the ulnar margin of the piece which supports the metacarpal bone of the little finger : this is the os pisiforme, although its situation is so low down.\nBetween the bone (1), which supports the metacarpal bone of the thumb, and the radius (a), the connexion during a long period is effected entirely by ligaments, without any appearance of the great scaphoido-semilunar bone which exists in the other sub-genera, but with age a small ossicle makes its appearance in this situation. In very large individuals, the two antepenultimate bones of the second row are consolidated into one.\nThe metacarpal bone of the thumb is","page":267},{"file":"p0268.txt","language":"en","ocr_en":"REPTILIA.\n268\nshort and broad ; the others are all long and slender. The little finger has only two phalanges, and is not longer than the thumb, so that the whole hand has a pointed shape. The thumb and the index finger only have their last phalanx armed with a nail.\nIn the land tortoises (fig. 181.), itisneces-\nFig. 181.\nAnterior extremity of the Tortoise.\nsary to admit that there are only two phalanges to each finger, or else to suppose, either that the last row of carpal bones is wanting, or that the metacarpal bones are deficient. By comparison, however, with the hands of fresh-water tortoises, it is evident that the bones present belong to the carpus and metacarpus.\nThis being allowed, the carpus is found to consist of a large radial or scaphoido-semi-lunar bone (a/), of two ulnar bones (c, d.), which are nearly of a square shape, of five bones of the second row (1, 2, 3, 4, 5,) supporting the metacarpal bones, and of an intermediate bone (e), situated between the great radial (a'), the first cubital, and those which support the third and fourth metacarpal bones. This intermediate bone is very frequently consolidated with the great scaphoido-semilunar bone, as represented in the figure.\nThe bones of the metacarpus in these tortoises are even shorter than the phalanges.\nHind Feet. \u2014 In the Chelonians, the os calcis does not project posteriorly, so that the tarsus is as flat as the carpus. In the turtles {fig. 182.), it is composed of six or seven bones, according as the last is reckoned as belonging to the tarsus or to the little toe. Two constitute the first row, of which the larger (a'), which is nearly of a rhomboidal shape, and connected both to the tibia and fibula, is the astragalus ; the smaller (h ), connected to the fibula alone, is the only representative of the os calcis.\nIn the second row there are four pieces, three of which are cuneiform bones, supporting the metacarpal bones of the great toe, and of the two following ones ; and the fourth, which is of larger size, appropriated to the two last metatarsals.\nThe metatarsal bones of the great toe and of the little toe are singularly broad and flat ; indeed, that of the little toe (c) might be taken for one of the tarsal bones a little removed from its place, in which last case the little toe would consist of only two phalanges : according to the former supposition it would\nhave three like the middle ones. The thumb or great toe has but two ; it is furnished with\nFig. 182.\nHind-foot of Tnonyx.\na nail at its extremity, as well as the finger which is next it ; the two following have their terminal phalanges large but without nails; the last phalanx of the little toe is very small.\nIn the land-tortoises the analogue of the Fig. 183.\nHind-leg of Tortoise.\nastragalus is more bulky and thicker, whilst the fibular bone or analogue of the os calcis is proportionally smaller. The other four tarsal bones are present, and in this case that which supports the little finger seems to form one of the series, both from its position and its shape ; sometimes it supports a rudiment of a little toe consisting of one piece only, but in many species this is wanting.\nThe metatarsal bone of the great toe is short but not flattened ; the others are a little longer : none of the four toes have more than two phalanges.\nIn the Chelonian reptiles, the os hyoides varies very remarkably as to its form in","page":268},{"file":"p0269.txt","language":"en","ocr_en":"REPTILIA.\n269\ndifferent genera, and even in different species. It generally consists of a body or centrum, which is sometimes itself divided into several pieces, and of two and sometimes three pairs of cornua ; also under the anterior part of its body there is suspended a bone or a cartilage (sometimes double) which is the special bone of the tongue, the analogue of the lingual bone of birds, only in them it is articulated in front of the body of the hyoid bone, whilst in the Chelonians it is suspended underneath.\nThe greater cornua (the anterior pair, when only two pairs are present, the middle pair when there are three, that which represents the styloid bones) embrace the oesophagus, and \u2018mount up behind those muscles which represent the digastric or depressors of the lower jaw, but without being attached otherwise than by their own muscles.\nIn Trionyx, the body of the os hyo\u00efdes, is composed anteriorly of a cartilaginous point, beneath which is suspended a large lingual cartilage of an oval form. At the base of each pointed cartilage there is attached an osseous piece of a rhomboidal shape, which represents the anterior cornua; behind this are four other pieces, forming a disc, which is concave superiorly, broadest in front, and deeply notched both posteriorly and on each side. To the anterior angles of this disc are appended the middle cornua and to the posterior the posterior cornua. All four of these cornua are considerably ossified. The middle cornua consist of one long piece, which is compressed, of an arched form, and terminated by a little cartilage. The other cornua are broader and flatter ; they are eked out by a cartilage, in the thickness of which are enclosed five or six osseous nuclei, all placed in a line with each other, each of a round or oval form, and quite hard and distinct, so that the os hyoides of this reptile seems to consist of twenty different osseous pieces, which apparently remain distinct through life.\nThe hyoid apparatus of Chelys is equally remarkable. Its body is composed of a single long narrow piece, of a prismatic shape, hollowed above into a canal in which the trachea is lodged. Anteriorly, this central portion expands in order to sustain two additional pieces on each side, four in all, without reckoning the centrum itself. The two middle ones unite in front, leaving a space between themselves and the principal body, which is closed by a membrane upon which the larynx reposes.\nThe two lateral pieces perhaps represent the anterior cornua ; it is at the dilatation that they form with the expanded portion of the centrum that the middle cornua are articulated : these are very strong and prismatic for the internal half of their course ; afterwards slender ; and they give attachment externally to an additional piece, which is distinct from the rest of the cornua.\nThe posterior cornua are articulated to the posterior extremity of the prismatic portion of the centrum; they are long, slightly compressed, and curved. Under the anterior and\ndilated portion is suspended the lingual bone, which consists anteriorly of a semicircular cartilage, and behind of two crescent-shaped osseous pieces, the inner angle of which is prolonged into a kind of tail or pedicle that passes beneath the prismatic body of the hyoid bone.\nIn the turtles, the body of the hyoid resembles an oblong shield, concave upon its upper surface for the sake of lodging the larynx and the commencement of the trachea ; pointed in front, where it forms part of the tongue, laying above the lingual bone. The anterior cornua are very small ; the great cornua are articulated to [the middle of its lateral margin, and have at their free terminations additional cartilaginous pieces. The posterior cornua are attached to the posterior angles.\nThe pelvis of lizards (\u00dfg. 184.) is composed\nFig. 184.\nPelvis of Crocodile, a, ileum ; i, ischium ; c, pubis.\nof three bones, which, as in quadrupeds, assist in the construction of the colyloid cavity. The os ilii (a) occupies the upper half; its neck is broad and short, and its spinous portion, instead of running forwards, as in mammifers, or being rounded, as in the crocodile, is directed obliquely backwards, in the shape of a narrow band.\nInferiorly, the pubis (b) and the ischium (c) are conjoined with their fellows of the opposite side along the mesial line ; but the pubis does not unite with the ischium, and consequently the two infra-pubic foramina are only separated from each other by a ligament.\nThe pelvis of the different genera of lizards are principally distinguished from each other by the symphysis of the pubic bones, which in the monitors is formed by the junction of two broad truncated surfaces; but in most other genera by a much less extensive union. The junction between the ossa ischii is always effected by a wide surface.\nThe chameleon differs from all other lizards in having the ossa ilii straight, and directed almost perpendicularly upwards, to be attached to the spine. They are likewise re-","page":269},{"file":"p0270.txt","language":"en","ocr_en":"270\nREPTILIA.\nmarkable, because they terminate in a triangular cartilage, analogous to that which ekes out the scapula.\nVestiges of the pelvis may be traced in Ophisaurus and Anguis, under the shape of a little os ilii, with a vestige of the ischium, but without any symphysis.\nThe cylindrical bones of the anterior and posterior extremities present nothing worthy of special remark.\nThe carpus (fig. 185.) consists of nine bones, the disposition of which is not unlike that of the carpal bones of a monkey. In the first row there is a radial bone (c), a cubital (d)t\nFig. 185.\nFore-leg of Crocodile.\na, the ulna ; b, the radius ; c, radial carpal bone; d, ulhar carpal hone ; e, os pisiforme ; f a lenticular hone interposed between the ulnar carpal bone and the metacarpal bones of the three inner fingers.\nFig. 186.\nHind-leg of Crocodile.\na, the tibia ; b, the fibula ; c, the astragalus ; d, the os calcis ; e, the os cuboides ; f, the cun\u00e9iforme, there is a flattened triangular supernumerary bone attached to the outer side of the cuboid, which in the figure has no letter of reference.\nFig. 187.\nTarsus of Lizard.\na, the tibia ; b, the fibula ; a', the astragalus ; b\u2019, the os calcis ; c, the os cuboides ; d, the cun\u00e9iforme.\nwhich is of large size, and an os pisiforme (<?) attached to the inferior extremity of the ulna. In the second row there are five small bones arranged in a curvilinear form, and corresponding with the five metatarsal bones : the ninth (/) is interposed between the two large bones of the first row, and the first, second, third, and fourth of the second, forming a kind of central piece to the carpus.\nThe tarsus of lizards, like that of the crocodile, is composed of four bones only.\nThe first row consists of two : one tibial (fig. 187, a'), which is likewise slightly articulated with the fibula ; the other fibular (b), of smaller dimensions, which, however, soon unites into a single piece with the former, situated on the same plane.\nThe second row likewise consists of two","page":270},{"file":"p0271.txt","language":"en","ocr_en":"REPTILIA.\t271\nbones, the larger of which (c) supports the metatarsals of the fourth and fifth toes, whilst the smaller (d) is situated between the preceding and the metatarsal bones of the second and third toes. This latter is also slightly connected with the astragalus, which alone supports the metatarsal bone of the internal or representative of the great toe.\nThe four first metatarsal bones are slender and nearly straight, becoming progressively longer as far as the fourth. The fifth is short, wide, and curved superiorly towards the larger of the two bones of the second row (c), to the side of which it is articulated.\nThe thumb or internal toe consists of two phalanges, the second of three, the third of four, and the fourth of five ; this is the longest toe in the foot of a lizard, giving to it the peculiar elongated and unequal form by which it is immediately distinguished. The fifth toe, although almost as short as the first, is composed of four phalanges.\nThe ungueal phalanges of all the toes are sharp, hooked, and pointed.\nThe above description, with slight differences as to the proportions, is applicable to all those subgenera of lizards which have their limbs fully developed, with the exception of the Chameleons and certain Geckos.\nEven in the chameleon it is the proportions\nFig. 188.\nAnterior Extremity of the Chameleon.\nof the carpal and tarsal bones that differ, rather than their number or arrangement. The five bones of the last row of the tarsus are very large and oblong, instead of being flattened. In the state of pronation and torsion in which the foot is placed, the os pisiforme is attached to the inner margin ofthe ulna, between it and the radius. The ulnar carpal bone {fig 188, d) and the radial (e) are\nsmall, the central bone (e) being the largest of all, and around this the five carpal bones of the last row are arranged like the spokes of a wheel. These five bones are longer than in ordinary lizards, and in fact represent the metacarpal bones as well as the last row of the carpus, leaving the fingers possessed of their proper number of phalanges. This remarkable arrangement permits the foot of the chameleon to be, as it were, split into two divisions. The thumb, the index, and the middle finger are connected by the skin into one group, which is turned inwards, while the two remaining fingers, similarly encased, are turned outwards, thus enabling this remarkable reptile to grasp firmly the boughs among which it lives by a mechanism very similar to that of the foot of a parrot or other scansorial bird.\nIn the tarsus of the chameleon the mechanism is very similar. The tibial tarsal bone (fig. 189, a'.) and the fibular tarsal bone {b')\nFig. 189.\nPosterior Extremity of the Chameleon.\nare equally of small dimensions, whilst the central bone of the tarsus (d), which articulates with both the above, is of a spherical form, and serves as a pivot for the movements of the foot. It has another bone (c) attached to its outer side, and the rest of its circumference is occupied by the attachments of the five metatarsal bones, the shape of which resembles precisely that of the corresponding bones in the hand; and in like manner they most probably represent the last row of the tarsal bones of ordinary lizards conjoined with those of the metatarsus. This being allowed to be the case, the thumb-finger of the chameleon consists of two phalanges, the first finger of three, the second","page":271},{"file":"p0272.txt","language":"en","ocr_en":"REPTILIA.\n272\nand the third of four, and the fourth of three, the same as in the hands.\nIt was an observation made as far back as the time of Aristotle, that the division of the anterior and of the posterior feet of the chameleon is effected in an inverse manner, the latter having the thumb and first finger only conjoined and turned inwards, but the other three turned outwards, whilst, as has been stated above, the anterior limb has three turned inwards and only two turned outwards,\u2014a beautiful provision for ensuring the steadiness of the creature\u2019s grasp.\nThe dragon {Draco) possesses fourteen pair\nFig. 190.\nSkeleton of Draco volans.\nof ribs, viz., six genuine, short, and curved ribs, which reach the breast-bone, and eight pail's of false straight ribs, which are seated in the wing membrane, and support the same. The posterior extremity of the ribs has a little head, in which there is a small socket of articulation, which is merely inserted upon the spherical articulating surface on the point of the transverse processes, and not at all into the bodies of the vertebrae. Owing to this remarkable mode of insertion, a very free joint is produced, enabling the ribs (especially those that are implanted in the wing membrane) to move forwards and backwards, and upwards and downwards, in different directions. Of the genuine ribs, the anterior ones are the shortest, and the posterior ones the longest ; they all terminate in a cartilaginous point, which attaches itself to the breast-bone. Of the eight pairs of false ribs, the five first pairs are very long, and the three following pairs are short, especially the two last pairs, which cannot be seen at all in the wing membrane. The false ribs become gradually thinner, and terminate at the edge of the wing membrane, in very fine cartilaginous points. In the whole animal kingdom, it is the dragon alone that exhibits this isolated and most remarkable structure. The wing membrane of the dragon distinguishes itself from the wing membrane of the flying squirrel by the circumstance of being supported by the ribs, which is not the case in the latter animals : the same circumstance likewise distinguishes their wing membrane from that of the bat, in which the prolonged anterior extremities, particularly those bones which are analogous to the finger joints, are continued into the wing.\nThe ribs, when flying, are moved by several muscles. Strong triangular muscles spring laterally from the bodies of the dorsal vertebrae, and are inserted into the lower edge of the commencing part of the false ribs. These muscles move the ribs, when flying, together with the wing membrane, downwards and slightly backwards. Other broad muscles, which have their source at the upper surface of the vertebrae, and which attach themselves to the ribs, move the ribs with the wing membrane. The alternating contractions and expansions of these muscles effect the fluttering or flying of the dragons. Thin muscles are likewise seated between the ribs, analogous to the intercostal muscles.\nOsteology of Ophidians.\u2014 In the true serpents, the vetebral column itself constitutes the principal portion of the skeleton, and the number of pieces of which it consists is sometimes prodigious, varying in different species, from about a hundred (Aconlias) up to three hundred {Boa) or even four hundred (Python) distinct vertebrae. These have pretty much the same shape throughout the whole length of the spinal column, each presenting the centrum or body, and the spinous, transverse, and articulating processes forming the bonds of connexion between them, or the levers by which they are wielded.\nThe bodies of contiguous vertebrae are","page":272},{"file":"p0273.txt","language":"en","ocr_en":"REPTILIA.\nconnected together by very perfectly constructed ball and socket joints, each vertebra presenting a concavity in front, and a convex ball upon its posterior aspect ; the plane of the circumference of the articulating surface being oblique from before to behind.\nThe spinous apophyses are generally elongated and flattened, being prolonged posteriorly to the articular apophyses, which they partially overlap.\nThe articulating processes are of two sorts ; some facing outwardly, represent ordinary articulating apophyses, with horizontal facets. The second face inwards, and are situated at the base of the spinous process. These apophyses are so arranged, that, as in the lumbar vertebrae of some Edentata amongst quadrupeds, two vertebrae are articulated together by a double tenon received into a double mortice, the only difference being, that the facets of the upper tenon and mortice are continuous, and form with each other ao acute angle.\nThe articular facets, without including those of the bodies, are twelve in number for each vertebra; an arrangement which restricts the vertical movements of the spine very materially, whilst at the same time it permits very free motion in a horizontal direction.\nThe transverse processes are very short and scarcely perceptible, except by a tubercle, which offers two facets for articulation with the ribs. In the caudal vertebrae, however, the transverse processes are much longer, and inclined downwards ; they are even double towards the anterior part of the caudal region.\nIn almost all serpents, the body of the vertebrae presents inferiorly a prominent longitudinal crest, which very generally terminates behind in a prominent spine, that is directed more or less towards the tail. In some genera, as in Crotalus, for example, this spine is even longer than the superior spinous process, and moreover is very frequently double.\nThe arrangement of the articular processes described above is not met with in the genera Anguis and Cecilia, in which it resembles what is found in lizards ; and in Amphisl\u0153na, Eryx, &c., traces, merely, of either superior or inferior spinous processes can be detected.\nThe ribs of serpents are enormously numerous, their number varying, according to the proportions of the species, from 51 pairs (Sheltopusick), up to three hundred and twenty pairs {Python). Each pair of ribs is move-ably articulated, by means of two slight concave surfaces, with corresponding articulating facets of the transverse processes of the corresponding vertebra, forming a kind of double ball and socket joint, which allows of an unusual extent of motion. There is no vestige of a sternal apparatus in any of the Ophidian reptiles, but each rib terminates by a single tapering cartilage, which is attached by muscular connexions, to be described hereafter, to the abdominal scuta of the integument.\nMyology of Chelonian Reptiles. \u2014 In the\nVOL. IV.\n273\nChelonian reptiles*, the cervical portion of the spine is composed of long and very moveable vertebrae, which form a curve, the concavity of which is upwards, whilst the dorsal region is converted into a broad immoveable shield by the consolidation of the ribs and vertebrae ; there consequently cannot be any muscles of the back, whilst those of the neck, on the contrary, are very distinct ; nevertheless, the attachments which they necessarily have beneath the back and the ribs, instead of on the outer side, as is usually the case, renders it exceedingly difficult to compare them with those of other animals. Still some points of relationship may be traced between them and those of birds. Thus, in the horizontal portion of the neck, close to the bones, are the intertransversales, separable, as in birds, into two sets of fasciculi, one upon the dorsal, and the other upon the ventral aspect. These are the intertransversarii colli and transversarii colli obliqui of Bojanus.\nThere is, moreover, in this horizontal part of the neck, the great transversalis, composed, as in birds, of two fascicles inserted into the transverse process of each vertebra, and derived from the transverse processes of the two preceding vertebrae. The anterior longus colli arises from the first dorsal vertebra ; it runs along all the ventral aspect of the curvature of the neck, receiving additional fibres , from, and giving off tendons to all,.\nAnother muscle, very similar in its dis- -tribution to the longus colli posti\u00e7us of birds, but slightly different in its insertion, arises from the carapax in front of the last vertebra of the neck, and gives off fleshy fasciculi to four or five of the vertebrae that precede it, but it inserts them into the crests, which represent spinous apophyses ; moreover, there is no accessory muscle as in birds. In one circumstance, however, there is a resemblance, namely, its last fasciculus, which is very long ; those likewise to the bead, where it is inserted into the upper aspect of the head, above the splenius : nevertheless it is not digastric, as that of birds. The larger portion of this muscle is named by Bojanus the spinalis colli, and the slip which it gives off to the head the splenius capitis : the tortoise has also a small complexus, which is derived only from the transverse apophyses of two or three of the anterior cervical vertebrae, and runs to the head, external to the splenius and to the fasciculus above mentioned. This splenius, which does not exist in birds, arises in the land and freshwater tortoises from the dorsal crests of the fourth, fifth, and sixth vertebrae, and runs to the head, where, dividing into two portions, it covers the upper surface of the occiput: this is the biventer cervicis of Bojanus. In the turtles its divisions are more widely separated ; the internal arises only from the most anterior vertebrae, whilst the external is derived from beneath the anterior edge of the\n* Cuvier, Le\u00e7ons d\u2019Anatomie Compar\u00e9e, last edition.\nT","page":273},{"file":"p0274.txt","language":"en","ocr_en":"274*\tREPTILIA.\nearapax ; this gives off a fasciculus to the ciently satisfactory ; but it is not so with the atlas, which is the splenius colli.\tlong muscles coming from the dorsal or\nSo far, even as regards the small mus- lumbar portion of the spine, which are redes of the neck, the analogies are suffi- placed by others having a totally contrary\nFig. 191.\nMyology of the European Tortoise.\n1, temporal muscle ; 3, digastricus ; 13, mylohyoides ; 16, hyomaxillaris ; 21, transverse muscle, embracing the neck; 40, obliquus abdominis; 41, transversus abdominis; 43, attrahens, and44, retrahens, pelvis ; 53, sphincter cloac\u00e6 ; 54, dilator cloacae ; 56, pectoralis major ; 57, serratus magnus ; 60 a and 60 b, delto\u00efdes; 62, superscapularis, representing the supraspinatus and infraspinatus of other animals; 65a and 65 c, triceps brachii; 66 a, 66 5, biceps brachii; 68, palmaris; 69, flexor sublimis ; 70, flexoris profundi tendines ultimi ; 71, pronator teres ; 73, ulnaris intemus ; 76, radialis extemus longus ; 78, supinator longus; 82, extensor proprius digiti minimi; 83, extensores quinque breves digitorum manus; 84, abductor pollicis; 87, lumbricales manus externi; 88, flexores digitorum breves; 91, iliacus internus ; 94, glut\u00e6i pars; 97, triceps femoris abductor; 101, vastus internus; 103, bicipitis cruris pars; 105 5, semimembranosis ; 106, sartorius ; 107, gracilis ; 108, extensoris communis digitorum tendo ; 109, tibialis anticus; 111, extensor brevis digitorum; 112, extensor proprius hallucis; 1145, gastrocnemius; 117, extremi tendines flexores, plantarem inter et soleum atque flexorem longum digitorum ; 118, flexores breves digitorum pedis ; 122, interossii digitorum pedis dorsales. (After Bojanus.')\nposition. Of these, in the land tortoises, and in the fresh-water tortoises, the principal is a thin lamina attached within the carapax to the ribs of the fifth and sixth dorsal vertebrae, and running together with its fellow of the opposite side obliquely forwards, and in the interval between the two lungs, on to the sides of the anterior or horizontal portion of the neck, where it is inserted by fasciculi to the transverse apophyses of the third, fourth, and fifth cervical vertebrae : it terminates by\na long fasciculus, which is inserted beneath the head to the basilar bone. This muscle draws the neck and head backwards, and to one side ; this is the retrahens capitis of Bojanus.\nA little more forward, and beneath the articulation of the fourth and fifth dorsal vertebrae, there is a similar muscle, which might indeed be regarded as a portion of the preceding, and which goes to be inserted into the side of the sixth cervical vertebra: this","page":274},{"file":"p0275.txt","language":"en","ocr_en":"REPTILIA.\ndraws the head and neck powerfully back-wai\u2019ds; it is the retrahens colli of Bojanus. In the opinion of Cuvier, the former of these two muscles corresponds in function to the sacro lumbalis, and to the transversalis ; the latter to the longissimus dorsi ; but modified in arrangement to suit the disposition of the skeleton. In the turtle they are reduced to a single fasciculus, which runs from the third dorsal vertebra to the basilar bone, performing the office of the r\u00e8ctus capitis anticus.\nThere is a third still more singular muscle which runs along the spine, receiving fibres from all the vertebrae, and traversing the intervals left between the heads of the ribs and the carapax, and terminating in front upon the anterior surface of the eighth cervical vertebra, which it draws forward, and with it the posterior vertical portion of the neck : its position reminds us slightly of the spinalis dorsi, but its insertion is very different.\nA muscular expansion, composed of transverse fibres attached on each side to the sides of the vertebrae, envelopes all the lateral and inferior portion of the neck, including the trachea and the oesophagus, joining in front the mylohyoideus, and connecting itself posteriorly with the inner borders of the plastron : this is a cutaneous muscle, similar to that which envelopes the neck of birds.\nIn the Chelonian reptiles, the muscles of the head cannot be designated by the same names as those of birds and mammalia, because the carapax gives origin to the greater number of them ; we must therefore content ourselves by indicating their attachments. Upon the posterior part of the neck we remark, first, at the anterior edge, towards the angle of its crescentic margin, a broad muscle which runs as far as the lateral and posterior parts of the head, where it is inserted : this will draw the head backwards.\n2d. Beneath, and from the middle of the anterior crescentic space, there arises another muscle,which is slender and round, and which, separating itself from its fellow of the opposite side, so as to form a figure of V, runs to be inserted upon the external border of the preceding : its office is similar to that of the last.\n3d. The analogue of the splenius capitis arises from the spinous processes of the third, fourth, and fifth vertebras of the neck by distinct slips, and is inserted into the occipital arch : this is the elevator of the head.\n4th. The analogue of the rectus anticus major arises from the inferior tubercles of the four cervical vertebrae which succeed the first, and is inserted fleshy into the basilar fossa beneath the condyle.\n5th. The trachelomastoideus arises from the inferior tubercles of the second and of the third cervical vertebrae, by two thin aponeurotic tendons ; it is inserted thick and fleshy into the eminence which corresponds with the mastoid process : this muscle bends the head to one side.\n6th. Lastly, at the upper part of the\n275\ncervical portion of the spine is a short muscle, which runs from the lower border of the hole formed by the temporal fossae to the spinous apophyses of the first, second, and third cervical vertebrae.\nIn front of the neck may be remarked the analogue of the sternomastoideus which arises from the strong aponeuroses which covers the humerus near its articulation with the scapula. Its inferior third only is visible when the skin is raised, the anterior two-thirds being covered by a transverse muscular expansion representing the mylohyoideus, and the platisma myoides. It is inserted underneath the apophysis that corresponds with the mastoid process. Its action will be to draw the head inwards, and slightly to elevate the shoulder.\nThe rectus capitis anticus arises from the inferior spine of the third vertebra of the back, and is inserted by a thin tendon into the basilar process of the occipital bone.\nIn the Chelonian reptiles the head is articulated with the atlas by means of a single condyle ; in the land-tortoises it is prolonged and divided into two ; in the turtles it presents three articulating surfaces resembling the leaf of trefoil. As this tubercle penetrates very deeply into the corresponding cavity of the atlas, the lateral movements of the head must be extremely limited ; the other movements of the head in the Chelonians are those of protraction and retraction : these depend upon the flexion and extension of the neck.\nIn the Trionyx, Nature has doubly provided against any lateral movement in the posterior region of the neck ; first, the articulations of the last cervical vertebra with the first dorsal are disposed so as to form an angular hinge, the posterior articular apophyses of the cervical forming a hollow cylinder, whilst the anterior articulating process of the dorsal is likewise cylindrical; secondly, the body of the eighth cervical terminates anteriorly in two condyles, which are received in corresponding cavities in the body of the seventh.\nIn the Matamata, which, instead of bending its neck vertically, bends it by lateral flexion, the disposition of the articulations is entirely different. The body of the eighth cervical vertebra is compressed laterally, and rounded at each end ; that of the seventh, on the contrary, is excavated at both extremities ; that of the sixth rounded posteriorly, and hollowed in front ; the fifth rounded at both ends ; and the others, as usual, concave posteriorly and convex before.\nIt results from this arrangement, combined with the disposition of the articular apophyses, that the neck is capable of a double lateral curvature.\nMuscles of the Shoulder. \u2014 These muscles in the Chelonian reptiles differ considerably from those of other vertebrate animals : they are four in number.\nThe first is attached beneath the edge of the carapax between the two ribs, and the pieces usually regarded as sternal ribs, from the second to the fifth. It is very thin, and\nt 2","page":275},{"file":"p0276.txt","language":"en","ocr_en":"276\nREPTILIA.\nFig. 192.\nMyology of the Tortoise.\n1, temporalis ; 2, pterygoideus ; 3, digastricus maxillae ; 14, omohyoideus ; 16, hyomaxillaris ; 17, genioglossus ; 18, hyoglossus ; 22, sternomastoideus ; 26, trachelomastoideus ; 27, retrahens capitis colli que ; 28, longus colli; 47, extensor caud\u00e6; 48, flexor caud\u00e6 lateralis; 49, flexor eaud\u00e6 inferior ; 58, latissimus dorsi ; 59, subclavius ; 64, subscapularis ; 65a, 65c, triceps brachii ; 70, flexor profundis ; 73, ulnaris internus; 74, ulnaris externus; 76, radialis externus longus; 78, supinator longus; 79* supinator brevis ; 83, extensores quinque breves digitorum manus ; 85, abductor digiti minimi ; 88, flexores breves digitorum quatuor ; 91, iliacus internus ; 94, glut\u00e6us ; 97, triceps abductor femoris ; 98, pectineus ; 100, vastus externus ; 101, vastus intemus ; 102, crureus ; 103, biceps cruris ; 104, semitendinosus ; 108, extensoris communis digitorum pedis pars; 111, extensoris brevis digitorum pars; 112, extensoris proprii hallucis pars; 116, soleus; 117, flexor longus digitorum pedis; 119, tibialis posticus ; 120, interosseus cruris ; 123, interossei digitorum pedis plantares.\nruns to the external border of the coracoid bone. From these insertions it cannot but be regarded as the serratus anticus (costo coracoidien) (fg. 191.57).\n2d. The elevator of the scapula is inserted at the middle internal portion of the scapula, and derives its origin by seven fleshy slips from the transverse apophyses of the seven last vertebrae of the neck.\n3d. Another small elongated muscle is attached beneath the carapax, near the sternal extremity of the first rib, and is inserted upon the dorsal extremity of the first bone of the shoulder: this is probably all that remains of the serratus magnus, for it must not be forgotten that here the muscles, as well as the bones, are in an inverse position. The above description is taken from the turtle ; in the land-tortoises the second muscle is very strong, and occupies all the length of the\nborder of the scapula. Bojanus considers it as representing the Scalenus.\n4th. There is a thin muscle met with in the fresh-water tortoises, of which Bojanus makes no mention ; this is inserted upon the anterior margin of the acromion ; it runs along the side of the neck, but without any attachment to the bones; it is lost in the general aponeurosis. If this be not regarded as a platysma, it can only represent the trapezius. In the emydes, vestiges of a dorsal cutaneous muscle are inserted into the aponeurosis of the subscapularis.\nMuscles of the Arm. \u2014 In order to understand the arrangement of the muscles of the shoulder and arm in the Chelonian reptiles, it is necessary to bear in mind that their scapula is styliform, that the acromion and the coracoid are singularly elongated, and that the entire scapula with the humerus are","page":276},{"file":"p0277.txt","language":"en","ocr_en":"REPTILTA.\t277\nFig. 193.\nMyology of the Tortoise.\n12, palpebralis, representing the orbicularis muscle of the eye ; 23, splenius capitis ; 24, biventer cervicis ; 33, transversalis cervicis ; 35, spinalis cervicis ; 40, obliquus abdominis ; 41, 41a, 416, transversus abdominis ; 42, a muscle thought by Bojanus to be analogous to the diaphragm ; 45, adducens pelvim ; 46, abducens pelvim ; 47, extensor caud\u00e6 ; 48, flexor caud\u00e6 lateralis ; 49\u201451, flexores caud\u00e6, inferior, lumbalis et obturatorius ; 53, sphincter cloac\u00e6 ; 58, latissimus dorsi ; 110, peroneus. The other muscles are indicated by the same letters as in the preceding figures.\nso disposed that the coracoid bone, instead of ternal, is anterior ; this arrangement, in fact, being anterior, as in mammalia, is internal, exists more or less in all oviparous verte-and that the acromion, instead of being ex- brata.\nFig. 194.\nMyology of the Tortoise.\n5, rectus oculi superior; 8, rectus oculi extemus; 11, suspensor oculi; 14, omohyoideus; 16, hyo-maxillaris; 18, hyoglossus; 22, sternomastoideus; 24, biventer cervicis; 25, complexus; 34, scalenus; 37, transversarii polli obliqui. The other muscles as in preceding figures.\nThe analogue of the great pectoral {fig. 191, 56) is composed of two superficial portions, one of which is attached to a ridge on the anterior part of the plastron, and goes to be inserted into the small tuberosity of humerus: the other is much more extensive ; it arises from a great portion of the internal surface of the plastron, and is likewise inserted by a flattened tendon into the lesser tuberosity of the humerus, but it is continued by an aponeurotic expansion, which spreads like a fan over the inferior surface of the arm, and even of the fore-arm : its tendon is united to that of the preceding.\nThe analogue of the deltoid (fig. 191, 60 a, and 606) arises from the extremity of the acromion, and goes to be inserted upon the external surface of the small tuberosity of the\nhumerus, uniting its tendon to that of the infra-spinalis.\nThe latissimus dorsi (fig. 192. 58) arises from the lateral part of the carapax as far as the articulation of the second rib, and runs nearly vertically towards the humerus, joining its tendon with that of the teres major, to be implanted in a fossa situated at the base of the internal tuberosity.\nThe supra-spinatus arises from the posterior aspect of the spine of the scapula, and runs to be inserted into the external tuberosity. In the turtles it is reinforced by a large muscle derived from the anterior edge and the superior surface of the extremity of the coracoid.\nThe infra-spinatus arises from the posterior border of the spine of the scapula, and runs to\nT 3","page":277},{"file":"p0278.txt","language":"en","ocr_en":"KEPTILIA.\n278\noin its tendon to that of the deltoid. In the turtles it is prolonged over all the posterior\nFig. 195.\nMyology of the Tortoise.\n2, pterygoideus ; 4, dilator tub\u00e6 ; 29, rectus capitis anterior longus; 30, rectus capitis anterior minor; 31, rectus capitis posterior major ; 32, rectus capitis posterior minor ; 36, intertransversarii colli ; 37, transversarii colli obliqui ; 39, longissimus dorsi ; 42, diaphragmaticus.\nface of the acromion, and is inserted a little higher up than the deltoid.\nThe subscapularis 0%. 201. 64) is the strongest muscle of the arm ; it arises from all the posterior surface of the scapula, and from three-fourths of the superior face of the coracoid, and runs to attach itself broadly to all the anterior face of the internal tuberosity ; its coracoid portion describes nearly a quarter of a circle to arrive at its destination. Its action must be powerfully to rotate the arm at the same time that the scapular portion advances it forward.\nThe teres major arises from the posterior edge of the scapula, and unites its tendon to that of the latissimus dorsi.\nIn the turtles there is a teres minor, which arises from the anterior portion of the posterior border of the scapula, and runs to be inserted close to the deltoid.\nThe coraco-brachialis consists of two portions, as in some mammalia, one of which, the larger, arises broadly from the inferior surface of the coracoid bone; the other, much smaller, arises between the preceding and the biceps : both are inserted near the subscapularis into the internal tuberosity of the humerus.\nIt will be seen from the above account that the muscles of the arm in the Chelonian reptiles are very similar to those of mammalia, only their different portions are more widely separated on account of the great prolongation of the acromion, and of the coracoid.\nMuscles of the Fore-arm. \u2014 The bones of the arm and the fore-arm not having undergone the same distortion as those of the shoulder, the muscles are less changed from the usual arrangement. The biceps alone coming from the coracoid bone, must necessarily follow its\nFig. 196.\nMyology of the Tortoise.\n9, obliquus oculi superior ; 10, obliquus oculi inferior ; 27, retrahens capitis collique ; 52, flexor caud\u00e6 ischiadicus. Other muscles indicated by same letters as in preceding figures.\nmovements ; it, however, always arises from its anterior margin, and passes along the bicipital groove when that exists in the Che-lonians. It is only fleshy at its coracoidal extremity ; all the rest consists of a tendon,\nwhich runs along the humerus to be inserted into the radius.\nThe brachialis internus occupies its usual situation, as also does the triceps brachii; the latter, however, is proportionally small, and","page":278},{"file":"p0279.txt","language":"en","ocr_en":"REPTILIA.\nin the turtles appears to have no scapular origin.\nFig. 197.\nMyology of the Tortoise\n71, pronator teres (insertion of) ; 72, pronator quadratus ; 75, radialis internus ; 88, flexores digi-torum breves ; 90, interossei digitorum manus in-terni.\nThere is only one supinator*, which is inserted into the wrist; it arises from the external condyle, but in the turtles this muscle is wanting. Both the pronators of the forearm are present in the land-tortoise ; however, the pronator quadratus is very small, and situated close to the carpus.\nMuscles of the Hand. \u2014 The muscles of the\nFig. 198.\nMyology of the Tortoise.\n86, abductor digiti tertii, quarti et quinti; 90, interossei digitorum manus interni.\nfingers are, in the turtle, few in number, their hand being so flatt\u00e8ned out into the shape of a fin or oar as to require neither flexors nor extensors of the fingers; in these, therefore, the analogue of the extensor digitorum communis is confounded with the general aponeurosis. The flexor communis is slightly more distinct; and the interossei, the abductors and adductors of the thumb and of the fifth finger exist, the latter serving to expand or to contract the oar.\n* Bojanus regards the muscle marked 79 {fig. 192) as a supinator brevis.\n279\nIn spite of the extreme shortness of the hand in the land-tortoises, the muscles are well developed, and the extensor communis, the extensor, and the long abductor of the thumb, the flexor sublimis, the flexor profundus, the adductor of the thumb, and the abductors of the little finger, as well as the interossei, are met with.\nMuscles of the Pelvis. \u2014 In the tortoise the\nFig. 199.\nMyology of the Tortoise.\na, glans penis ; b, bulbus penis ; c, vein derived from ditto ; 50, flexor caud\u00e6 lumbalis ; 51, flexor eaud\u00e6 obturatorius ; 52, flexor caud\u00e6 ischiadicus ; 55, protrahens penis.\nmuscle analogous to the quadratus lumborum spreads out beneath the carapax between the antepenultimate ribs: it is inserted into the ileum near the articulation of that bone with the sacrum, that articulation being in the Chelonians moveable.\nThis mobility of the pelvis is aided by the analogue of the rectus abdominis, which, instead of spreading out beneath the belly, is attached under the posterior extremity of the plastron by two fleshy bellies, one in front and the other behind ; both run to be inserted into the anterior margin of the external ramus of the pubis.\nMuscles of the Thigh. \u2014 In the land and fresh-w'ater tortoises, although the ossa ilii are very narrow, the muscles belonging to the thigh are of considerable thickness. The glut\u00e6us maximus, which might almost be mistaken for a pyramidalis, is only attached to the ileum by a small proportion of its fibres, the remainder are derived from the transverse apophyses of the caudal vertebrae. The glut\u00e6us m\u00e9dius and minimus, united together at their origin, constitute a mass which arises from all the external surface of the ileum, from its anterior border, slightly from its internal surface, and even from the inferior surface of the seventh rib : this muscle divides into two tendons, one of which, that of the glut\u00e6us m\u00e9dius, is inserted into the trochanter; the other, that of the glut\u00e6us minimus, a little lower down into the body o. the femur.\nThe obturator internus is a very strong muscle arising from the upper aspect of the internal ramus of the pubis, and winding around the ischium, as in mammalia, to be inserted into the great trochanter.\nThe quadratus femoris exists, but neither gemelli nor pyramidalis are present.\nThere is no psoas; but theiliacus is strong, and arises from the upper part of the internal\nt 4","page":279},{"file":"p0280.txt","language":"en","ocr_en":"280\tIlEPTILIA.\nsurface of the pubis, confounding its anterior margin with that of the glut\u00e6us m\u00e9dius. The obturator externus (adductor of Bojanus) arises by two portions, one coming from the pubis, the other from the ischium ; their two tendons unite to form a broad tendon, which is inserted into the two trochanters.\nThe adductors of the thigh do not arise from the pubis, but from the ischiadic portion of the symphysis.\nA muscle, the analogy of which it is difficult to recognise, arises from the upper surface of the pubis, and goes to be inserted by a strong tendon at the side of the iliacus (iliacus internus of Bojanus, surpubien of Cuvier). In the turtles there is no iliacus, and the suprapubic muscle divides into two fasciculi, the external of which goes to the knee, and joins the'rectus of the thigh.\nMuscles of the Leg. \u2014 The muscles of the leg are more recognisable than those of the thigh.\nIn the land-tortoises these muscles are the triceps ; the sartorius, which is divided into two portions ; the semimembranosus, which has a large accessory slip derived from the coccyx ; the rectus anticus, which is situated slightly internally, has an origin from the external ramus of the pubis, and is connected with the articular capsule of the knee joint ; the gracilis is confounded at its origin from the ischium with the adductors of the thigh, but it separates from them, and is inserted at some distance from the head of the tibia. In the turtles the muscles are not so thick as in the land-tortoises; the advanced position of the pubis gives to the anterior rectus great force in extending the thigh and the leg, for it is inserted into the knee almost at a right angle. The biceps and the semimembranosus arise from the coccygeal region only.\nIn the terrestrial tortoises the movements of the foot upon the leg, and of the different parts of the foot one upon the other, are very limited, and consequently the muscles which execute them are indistinct.\nThere is but one peroneus, which is confounded by one of its margins with the extensor communis, and which is inserted into c the os calcis and into the cuboid.\nThe gastrocnemius externus alone takes its origin from the femur ; the gastrocnemius internus arises from the tibia and joins itself to the sol\u00e6us. This latter is divided into three portions, one external, one median, the other internal. These muscles, in conjunction with the peronei and the long flexor of the toes, form beneath the foot a thick tendinous mass ; they extend the foot upon the leg, and flex the latter upon the thigh ; but it is next to impossible to distinguish the different portions.\nThe tibialis anticus is distinct.\nIn the t\u00f9rtles which have the foot, like the hand, flattened into the shape of an oar, the gastrocnemii are disposed as in the land-tortoises, and the soleus is equally strong. There exists, moreover, a slender plantaris longus, which arises from the external tube-\nrosity of the femur by a long round tendon, and which terminates in a broad expansion,\nFig. 200.\nMyology of the Tortoise. (After Bojanus.)\n119, tibialis posticus ; 120, interosseus cruris ; 122, interossei digitorum pedis dorsales; 123, in-terossei digitorum pedis plantares.\nwhich is inserted partly into the os calcis, and partly into the plantar fascia. This muscle is from its position an adductor of the foot. The tibialis anticus preserves its ordinary relations ; but the tibialis posticus runs from without to within, and its tendon becomes lost in the plantar fascia.\nThe toes of the Chelonians not having more flexibility than their fingers, the muscles of the foot are much confused. The extensor communis longus digitorum, as in all other reptiles, only reaches as far as the bones or the metatarsus. The extensor brevis alone reaches to the phalanges of the toes.\nThere is, however, a proper extensor for the great toe, which arises from the inferior extremity of the fibula, an abductor of the little toe, and interossei, which latter, as in mammalia, are both adductors and abductors.\nIn the turtles the extensor communis spreads out as it approaches the toes, and forms a broad aponeurosis, which covers the whole foot.\nThe extensor longus, and the abductor of\nFig. 201.\nMyology of the Tortoise. (After Bojanus.')\n117, tendons of the flexor longus digitorum ; 118, flexor brevis digitorum pedis.\nthe inner toe, arise from the inferior extremity of the fibula, and are inserted into the metatarsal bone that supports this toe, as well as into the first and second phalanges.\nAnother muscle, which also arises from the inferior extremity of the fibula, is inserted into the whole length of the metatarsal bone of the fifth toe, and upon its first phalanx : it is both an extensor and an adductor.","page":280},{"file":"p0281.txt","language":"en","ocr_en":"REPTILIA.\n281\nThe flexor brevis digitorura gives off* a slip to each of the three middle toes.\nMyology of Ophidian Reptiles. Muscles of the Spine. \u2014 In serpents, as might be expected, the muscles of the spine are very completely developed, and easy to identify.\nThe spinalis dorsi arises from the lateral surface of the spinous processes of the vertebras, and likewise receives tendons of reinforcement from the longissimus dorsi, which spread out and are lost upon its inferior surface ; this muscle divides itself internally into as many fasciculi as there are vertebrae, each fasciculus terminating in a very long tendon, which runs in an aponeurotic sheath to be inserted into the spinous process of the vertebra to which it is destined.\nThe longissimus dorsi arises by fleshy fibres from the extremities of the articular apophyses, which here perform the office of transverse processes. These slips, after having become united with each other, give off two sets of tendons, one of which runs obliquely to assist in giving origin to the spinalis dorsi; the others descend in like manner, and constitute the only tendons of origin of the sacro-lumbalis, so that this muscle cannot be said to have any direct insertion upon the vertebral column.\nThe sacro-lumbalis arises from the tendons of the longissimus dorsi just described, and divides itself externally into slips, each of which is inserted by a slender tendon into the posterior edge of the upper third of one of the ribs.\nUnder the spinalis dorsi is found the semi-spinalis (transverso-spinalis), and beneath this the interspinalis.\nOn the inferior aspect of the vertebral column there is found a muscle in all respects analogous to the longus colli, except as regards its extent, and which might be called the transverso-spinalis inferior : this extends from the inferior spinous process of one vertebra to the transverse processes of the second and third succeeding vertebrae.\nAll the above six muscles exist from the end of the tail as far as the head ; their last fasciculi, viz. those inserted into the skull, although their arrangement is slightly altered, cannot be considered on that account as being distinct muscles. The sacro-lumbalis, moreover, on arriving at the caudal region, is inserted into the transverse processes of the caudal vertebras, instead of into the ribs, so that as the tail becomes attenuated these muscles are blended together: nevertheless, there are always vestiges of them perceptible.\nMuscles of the Ribs. \u2014 These are the trans-verso-costal muscles, arising from the transverse processes of each vertebra, and running to be inserted into the following rib, for about the superior fourth of its length.\nThe great lateral costal muscles which cover the side of the trunk of the body, arise behind the insertions of the preceding, each passing obliquely over four ribs, to which it gives off' a few fibres, is inserted\ninto the fifth behind that from which it takes its origin.\nFig. 202.\nLateral View of the Muscles which move the Ribs of the Boa Constrictor.\naa, the straight muscles of the back; b, the first set of muscles, which arises from the transverse processes of each vertebra, and is inserted into the rib behind it, close to its head ; c, the second set ; d d, the third set ; E, the fourth set ; F, the fifth set ; g G, short muscles which pass from cartilage to cartilage; hh, a set of oblique muscles, which pass from the anterior side of the bony extremity of each rib to the posterior edge of each scutum ; 11, muscles which pass from the ribs, near their heads, obliquely backwards, to be inserted into the skin at the edge of each scutum; k, muscles of the scuta. (After Home. )\nThe great inferior costals take their origin below the preceding, and are inserted in the same manner, only their direction is more longitudinal, so that they occupy a smaller proportion of the length of the ribs.\nThe smaller costal muscles are placed between the two preceding sets, and pass from one rib to the next behind it.\nThe intercostal muscles occupy their ordinary position, and, as usual, are arranged in two planes which decussate each other.\nIn addition to the above, there exists in the interior of the thorax an inferior transverso-costal muscle; this arises from the angle of the tubercle to which the rib is attached, and running obliquely forwards, passing three ribs, is inserted into the fourth a little below the","page":281},{"file":"p0282.txt","language":"en","ocr_en":"REPTILIA.\n282\nmiddle of its length. This muscle is described by Sir Everard Home* as being in the boa constrictor divided into two, an upper and a lower portion ; but in other species, although a slight line of demarcation may be detected, such a division is scarcely admissible.\nFrom the ribs of serpents muscular fasci-\nFig. 203.\nAn internal View of the Muscles which move the Ribs in the Boa Constrictor.\nA a, tlie muscles which pass from cartilage to cartilage of the different ribs ; b b, a set of muscles which pass from the point of each rib, over two ribs to the middle of the third; c, a similar set of muscles continued from the opposite side of the rib, passing over three ribs to the body of the vertebra ; dd, the abdominal muscles which arise from the anterior edge of each rib, and pass to the linea alba ; e, the linea alba; ff, the terminations of the oblique muscles which pass from the bony extremities of the ribs to the edges of the scuta; gg, the muscles of the scuta, consisting of two sets, which decussate each other.\nculi are given off, which go to be inserted into the skin : some of these arise from the same point as the great lateral costals. Their course is from before backwards, and from above downwards as they run, spreading out like a fan, to be attached to the sides of the ventral scuta. The others arise from the lower part of the rib, opposite the point of attachment of the long inferior costal muscle ; these run from behind forwards to be fixed to the angle of a ventral scutum, about\n* Lectures on Comp. Anat., vol. i.\nthree ribs off. The ribs, moreover, give attachment to a visceral muscle.\nIn serpents there is only one muscle proper to the head, which seems to represent the complexus ; this arises from the articular apophyses of the five or six anterior vertebrae, and is inserted into the mastoid bone.\nThe transverso-spinalis is continued as far forwards as the occipital bone, and thus replaces the recti capitis. The movements of the head upon the spine are, indeed, very limited in the ophidia. The body of the atlas presents three articular facets arranged after the manner of the leaves of a trefoil, which are attached to the occiput beneath the foramen magnum, so that the head is not more moveable upon the atlas than the other vertebras upon each other.\nThe muscles of the head of serpents have been carefully dissected by M. Dug\u00e8s*, M. Duvernoyf, Brandt and Ratzburg J, and others. The following brief account of this part of their myology, taken from the last edition of Cuvier\u2019s Anatomie Compar\u00e9e, must, however, suffice for our present purpose.\nThe true serpents have the zygomatic ([tympanic) bones (fig. 205, 7) moveable, and suspended from another bone analogous to the mastoid (6), which is attached to the cranium by means of muscles and ligaments that allow of considerable mobility : the two sides of the lower jaw, moreover, are but loosely connected with each other, and the superior maxillary bones (2) are only united to the inter-maxillary bones (1) by ligaments, so that they can be separated to a greater or less extent ; a circumstance which confers upon these reptiles the faculty of dilating their rictus, thus enabling them to swallow animals whole which could not otherwise by possibility pass into their mouths. In addition to the above arrangement, the maxil-laries (2), the palatine bones, and the ossa' pterygoidea (3, 4), are more or less moveable beneath the cranium, so that the animal can raise or depress the palatine or pterygoid arches, as well as those formed by the upper maxilla, and also can separate them, or approximate them to each other.\nThe muscles subservient to the movements of the jaws are the following : \u2014\nAll serpents whose mandibular arches are moveable, as above described, have generally three distinct temporal muscles, one anterior, one median, and the other posterior.\nThe anterior temporal (fig. 204, e) is attached superiorly behind the orbit, and descending downwards and backwards, winds round the commissure of the lips, and turning forward again (e'), is inserted into the lower jaw, very considerably in front of the angle of the mouth.\nThe middle temporal (fig. 204, i.) is partly covered by the anterior temporal, it descends nearly vertically from the middle and upper\n* Ann. des Sc. Nat. tom. xii. 1827. p. 378.\nf Ann. des Sc. Nat. tom. xxvi. 1832. p. 113.\nJ Medezinische Zoologie, 4to. 1829","page":282},{"file":"p0283.txt","language":"en","ocr_en":"REPTILIA.\n283\nportion of the temporal fossa, until it meets the jaw into which it is inserted, either separately or conjointly with the anterior temporal.\nThe posterior temporal (/), which is always distinct from the two others, descends from the very posterior part of the temporal fossa, along the zygomatic bone (tympanic) (fig. 205, 7), to the lower, into which it is inserted behind the two others.\nThe mouth is opened by means of a muscle\nFig. 204.\nThe Muscles of the Head of the Rattlesnake.\na a, poison gland and ils excretory duct; e, anterior temporal muscle; f, posterior temporal muscle ; g, digastricus ; h, external pterygoid muscle; i, middle temporal muscle; q, articulo-maxillary ligament which, joins the aponeurotic capsule of the poison gland ; r, the cervical angular muscle; t, vertebro-mandibular muscle; u, costo-mandibular muscle. (After Duvernoy.)\n206, v), which passes transversely from one to the other. This muscle, which is tendinous\nFig. 205.\nMuscles of the Pterygo-Palatine Apparatus of the Rattlesnake ( Crotalus durissus').\t(After Du-\nvernoy. )\nanalogous to the digastric (g), which arises from the whole length of the posterior aspect of the zygomatic (tympanic) bone, and terminates on each side at the angle of the jaw beyond its articulation.\nThere is likewise a cutaneous muscle which powerfully contributes to depress the lower jaw, something like the platysma myoides ; this has been named the costo-mandibu-laris (u). This, moreover, is assisted by a strong fasciculus (t), derived from the spinous processes of the vertebrae immediately behind the cranium, which has been distinguished by the name of the vertebro-mandi-bularis.\nTwo sets of muscles are appropriated to the movement of the zygomatic (tympanic) bone which supports the lower jaw : of these one arises on each side from the back of the occipital region, and is inserted into the lower portion of the bone above referred to.\nThe other (fig. 205, m) is azygos, and has been named by M. Dug\u00e8s sub-occipito artica-laris, its fibres run across beneath the base of the skull, from the articulation of the lower jaw on the one side, to that on the other. The former pair of muscles will draw the branches of the lower jaw upwards and inwards, the azygos muscle will move them inwards and downwards.\nThe anterior extremities of the lower jaw can be approximated by a little muscle (fig.\n1, intermaxillary and nasal bones ; 2, 2, superior maxillary bones ; 3, external pterygoid bone ; 4, internal pterygoid bone ; 5, palatine arch ; 6, mastoid bone; 7, the tympanic bone; a, capsule of the poison-gland ; a', duct of ditto ; h, h, external pterygoid muscle; k, internal pterygoid muscle; 1,1, spheno-pterygoid muscle; m, the suboccipito-articular muscle (of Dug\u00e8s) ; n, the spheno-palatine muscle ; o, the spheno-vomerine muscle.\nalong the mesian line, is analogous to the mylo-hyoideus ; it likewise gives off a slip v', which is attached to the skin.\nThe muscles belonging to the maxillary and palatine bones are,\u2014\nThe external pterygoid (fig. 204, h), which, arising from each jaw, runs directly forward as far as the maxillary extremity of the external pterygoid bone, which it draws powerfully backwards. In venomous serpents with anterior poison fangs, which have the external pterygoids very long, and the maxillary bones very short, this muscle is very strong, arising by aponeurotic fibres, from the capsule which encloses the articulation of the lower jaw, whence it runs forwards towards the pouch in which the venomous teeth are lodged, upon which it is partially spread out ; its principal attachment, however, is to the posterior apophysis of the superior-maxillary bone, into which it is inserted by a distinct tendon. The use of this muscle is evidently to carry backwards the venomous fangs when they are to be laid flat, and to incline them towards the palate, a position that they retain while in a state","page":283},{"file":"p0284.txt","language":"en","ocr_en":"284\nREPTIL! A.\nof repose, in which condition it covers them by drawing the inclosing pouch over them.\nThe internal pterygoid (k), shorter and smaller than the external, runs from the alar bone to the posterior part of the lower jaw, which it consequently draws forwards.\nThe spheno-pterygoid (/), which has no analogue in other vertebrata, arises from the mesial portion of the base of the cranium, and runs outwards and backwards to be attached to the inner surface of the pterygoid plate, which it can thus drag forwards and inwards so as to cause the protraction of the superior maxillary bone, thus raising the venom fangs ; it will likewise narrow the mouth by causing the approximation of the two internal arches. It is assisted in its action by a muscle, which Cuvier regards as a dismemberment of the temporal, the post-or-bito-palatine, which runs from the temporal fossa behind the orbit to the palatine arch.\nThe spheno-palatine {fig. 205, n) antagonises the two last ; it extends from all the length of the palatine arch to the mesial line of the base of the cranium ; its direction crossing that of the preceding muscle, above which it is placed. By its contraction it brings backwards the entire upper jaw, approximating at the same time the branches that form it.\nTwo small muscles {fig. 205, o) advance from beneath the sphenoid, and run close to each other to be inserted by a slender tendon into the vomer. These are the spheno-vomerine muscles of Dug\u00e8s, for which it would be difficult to find analogues. These muscles depress the muzzle.\nIn all the true serpents the tongue is enclosed in a membranous sheath, to be described hereafter ; and the os hyoides, which in the ophidia has no connexion with the larynx, consists of two simple cartilaginous stems {fig. 206, b,) running parallel to each other, which bend forwards underneath the sheath of the tongue, where they unite to form a sort of arch of almost membranous consistency. Corresponding with this simple form of the os hyoides; the hyoid system of muscles is very simple. The mylo-hyoideus, above described as being an adductor of the two divisions of the lower jaw, has some of its fibres confounded with those of the costo-mandibular muscles {figs. 204. 206, u), which, coming from the anterior ribs, is attached to the lower margin of the inferior maxilla. Its central fasciculi are adherent to the rami of the os hyoides, and more especially to the membranous arch which they form in front. They can therefore draw it either forwards or backwards, accordingly as it is the maxillary or the costal portion which contracts; and thus these fasciculi hold the place of both sterno-hyoidei and genio-hyoidei. In serpents, therefore, there are no muscles exclusively appropriated to the os hyoides.\nThe tongue of serpents is slender, cylindrical, and forked at its extremity. It is lodged in a membranous sheath, the opening of which is situated near the anterior part of the mouth, and the animal can protrude it from its mouth\nto nearly its whole length, using it as an instrument of touch, apparently comparable in\nFig. 206.\nMuscles of the Throat of the Rattlesnake ( Crotalus dur issus').\nA, retractor muscles of the tongue (Hyo-vagi-niens) ; b, cornua of the os-Hyoides ; h, external pterygoid ; u, u, u, u, costo-mandibular muscles ; v, v, anterior adductor muscle of the rami of the lower jaw ; v', v1, portion of the preceding connected with the skin of the throat ; x, posterior adductor of the rami of the lower jaw ; y, a muscle running from the symphysis of the lower jaw to the sides of the trachea (genio-trachien) ; z, geno-vaginalis, representing the genio-glossi ; zr, z\", external and internal origins of ditto.\nsome respects to the antennae of insects. The muscles by the agency of which it is protruded, are the genio-vaginales {fig. 206, z), representing the genio-glossi. These arise by two fasciculi, of which the internal and smallest {%') arises from the tendinous median portion of the adductor of the inferior maxillae (v); whilst the external {z\"), which is the strongest, takes its origin from the extremity of the lower jaw itself : these two portions unite and form a narrow band, which becomes applied to the sides of the sheath of the tongue, along which it is continued backwards to its extremity.\nThe retractors of the tongue {fig. 206, a) are analogous to the hyo-glossi ; they arise around the extremities of the rami of the os hyoides, and running forwards conjointly, enter the sheath of the tongue, and its proper investing membrane ; so that they constitute the entire","page":284},{"file":"p0285.txt","language":"en","ocr_en":"REPTILIA.\nsubstance of that organ. The flexibility of the tongue seems to depend entirely upon the different muscular fasciculi of which these muscles are composed, having the power of contracting separately, some being longer or shorter than others, accordingly as they terminate successively in the proper membrane of the tongue to which they are attached ; for there seem to be no transverse or oblique fibres constituting intrinsic lingual muscles.\nThe mechanism by which the Cobra de Capello, when irritated and ready to seize its prey, expands the skin of the neck, giving it the appearance from which the snake takes its name, consists entirely of muscles, acting upon the ribs and external skin of the animal.\nFrom the rounded form of the hood, the skin has the appearance of being inflated ; but the most careful examination does not discover any communication between the trachea or the lungs, and the cellular membrane under the skin.\nIn this snake, the ribs nearest the head, to the number of twenty on each side, have a different shape from the rest ; instead of bending equally with the other ribs towards the belly, they go out in a lateral direction, having only a slight curvature, and when depressed, lie upon the side of the spine, on one another.\nIn the extended state of the ribs, the skin of the back is brought over them, forming the hood ; and in their depressed state the hood disappears.\nThe ribs are raised by four sets of muscles : one set from the spine to the upper edge of each rib ; a second set from the ribs above, passing over two ribs to the third rib below ; another set have their origins from the rib above, pass over one rib, and are inserted into the second below ; and a fourth set pass from rib to rib. The combined effect of these four sets of muscles raises and extends the ribs.\nThe skin of the back is brought forwards on the neck, by a set of very large muscles, going off from each of the first twenty ribs on each side, a quarter of an inch from their head, by a tendinous origin, which soon becomes fleshy; the longest of these muscles are two inches long. They are inserted into the skin, and, when the ribs have been first extended, have the power of bringing the skin forwards to a great extent.\nMyology of Salamander (Salamandra ter-restris). In-order to complete our survey of the myology of the reptilia, it has been deemed advisable to introduce in this place a brief sketch of the muscular system of the amphibia, which is obviously arranged upon the same plan as that of the quadruped reptiles properly so called, and from its comparatively embryo condition is a subject of much interest.*\nMuscles of the Head. \u2014 The movements of the eye are effected in the usual manner by means of the four recti and two oblique muscles, the disposition of which is similar to what exists in reptilia generally.\nThe movements of the jaw subservient to mastication, are performed by the agency of * See the article Amphibia.\n285\nfive muscles. Of these the first is a long muscular slip (fig. 207, 1.) that takes its origin from the arch and spine of the first vertebra of the neck, and which, together with a broad triangular muscle (2), corresponding to the temporalis, that arises from the lateral region of the os-frontis and the parietal bones, is inserted in front of the os quadratum into the upper margin of the lower jaw. A third muscle (3), analogous to the masseter, arises at the upper extremity of the os quadratum towards its anterior part, and extends to the external surface. The three preceding muscles serve to close the jaws ; they are antagonised by a short muscle (i) derived from the quadrate and temporal bones ; whose attachment to the lower jaw is placed behind the centre of motion of the articulation of the jaw, and consequently its effect will be to open the lower jaw.\nLastly, there is an external pterygoid muscle, provided for the lateral movements of the inferior maxilla.\nMuscles of the Trunk. \u2014 Running along the whole length of the back there is the broad lateral muscle (fig. 207, 5), which likewise forms the principal part of the lateral walls of the abdomen. This muscle forcibly reminds us of the great lateral masses of muscle which form the principal part of the body of fishes, and, in like manner, it is divided by tendinous intersections into as many portions as there are vertebrae in the spine. Its commencement may be traced as far forwards as the occipital quadrate and temporal bones : it likewise has points of origin from the spinous and transverse processes of the whole vertebral column. These two lateral masses are separated above by a deep furrow (5 a), which is filled up with a series of cutaneous glands peculiar to these animals. The dorsal portion is with difficulty separated into an upper and lower stratum, of which the upper and more external may be compared to the sacro-lumbalis, while the lower and broader one seems to represent the longissimus dorsi. The cephalic extremity, having numerous points of attachment in the neck, and likewise the occipital region of the skull, forms several muscular bundles, more or less distinct from each other, which represent the muscles of the neck.\nThe representative of the external oblique muscle of the abdomen (6), is here evidently merely a continuation of the great lateral muscle above described. In this region, however, it attaches itself more particularly to the rudiments of the ribs and to the contiguous transverse process of the vertebra, extending from the second vertebra of the neck as far back as the pelvis ; inferiorly, it is connected with its fellow of the opposite side by a tendinous interlacement, representing the linea alba.\nThe internal oblique muscle of the abdomen is represented by the inner layer of the preceding. By the partial separation of these two muscular layers, a sheath is formed which partially encloses the Pubo-hyoideus.","page":285},{"file":"p0286.txt","language":"en","ocr_en":"REPTILIA.\n286\nThe last named muscle (Shawzungenbein-muskel) {fig. 208, 7) arises partly from the os-\nFig. 207.\nMuscles of Salamander terrestris.\npubis and partly from the outer border of the\nY-shaped pelvic cartilage, whence it runs forward along the whole length of the abdomen, enclosed in a sheath, formed between the internal and external oblique muscles of the abdomen as far as the throat, where it is inserted into the middle cornea of the os-hyoides.\nThe rectus abdominis (fig. 208, 8) takes its origin entirely from the Y-shaped pelvic cartilage, and, first attaching itself to the triangular lower rudiment of the sternum, over which it passes, it becomes again connected with the upper transverse piece of the sternum, from whence it sends a slip forwards to be inserted into the centre of the lower jaw : this last portion represents the genio-hyoi-deus.\nIn its course, this muscle is divided by several tendinous intersections. It is, moreover, attached with some firmness to the pericardium, in the neighbourhood of which it gives off two additional slips of muscle, one of which passes obliquely outwards to join the pubo-hyoid ; the other (10) runs to be inserted into the scapula, becoming likewise connected with the scapulo-humeral articulation.\nThe mylo-hyoideus (fig. 208,11) fills up the entire space betwen the arches of the lower jaw, from the angle of which, likewise, arise two cutaneous muscles (fig. 207, 12) and (fig. 208, 13), one of which extends into the skin of the inferior and anterior region of the neck, whilst the other mounts backwards and outwards to be similarly inserted into the skin upon the sides of the cervical region. A muscle(y%. 208,14) passes from the lower jaw near its symphasis, to be inserted into the extremity of the anterior cornu of the os-hyoides ; whilst a second slip (15) passes from the anterior to the central cornu of the latter bone.\nMuscles of the Extremities. \u2014 The pectoralis major (fig. 208, 16) consists of two portions, one of which, 16 a, represents the clavicular portion in the human subject ; it entirely covers the lower surface of the shovel-shaped clavicle, so that it seems to form a distinct muscle.\nThe following muscles are immediately recognisable from their position : The latissi-mus-dorsi(y%.207,11) ; the levatores-scapul\u00e6 (fig. 207, 18 and 19) ; a muscle (20), the office of which is to draw the shoulder forwards. This muscle is derived from the sides of the occiput and anterior cervical vertebra, and extends to be inserted into the shoulder-blade near its articulation. The serratus magnus anticus (fig. 208, 21) consists of only two small slips derived from the transverse processes of the second and third vertebrae of the neck, and connected with the great lateral muscle of the trunk. The shoulder likewise possesses a muscle (22) that represents both the supra and infra spinatus, and a subscapularis occupying its usual position.\nThe muscles of the humeral region are the representative of the biceps, and brachialis","page":286},{"file":"p0287.txt","language":"en","ocr_en":"REPTILIA.\ninternus (j%. 208,23), and the triceps extensor of the fore-arm.\nFig. 208.\nMuscles of Salamander terrestris.\nOn the fore-arm may be distinguished the flexor carpi radialis (25), the flexor carpi ulnaris {fig. 207, 26), the extensor carpi ulnaris (27), the extensor carpi radialis {fig. 208, 28), a flexor communis digitorum (29), and an extensor communis digitorum (30).\n287\nMuscles of - the hinder Extremity. \u2014 The thick flexor of the thigh {fig. 207, 31), representing the iliacus internus, arises broadly from the whole inner surface of the os ilei passes over the os pubis, and is inserted into the femur below its middle. The long extensor and adductor of the thigh (32) arises from the third and fourth caudal vertebrae, and is inserted into the posterior aspect of the femur about its middle.\nThe long abductor of the leg {fig. 207, 33) arises from the external surface of the os ilei, and is inserted into the tibia about its lower third. The anterior abductor of the thigh {figs. 207 and 208, 34) arises from the anterior and internal surface of the os ilei, and is inserted into a broad tendinous expansion that covers the knee-joint. The thin flexor of the leg (fig. 208, 36) arises from the inferior lateral surface of the os ilei, and is inserted into the outer part of the head of the tibia.\nA longmuscular slip (figs. 207 and 208, 37) arises from the transverse processes of the third and fourth vertebrae of the tail, and is inserted into the back of the thigh bone.\nThe chief muscle of the sole of the foot (^38) arises from the side of the sacrum, and is inserted into the thick fascia of the sole. The other muscles of the foot are an extensor and abductor of the tarsus (39), which arises from the upper end of the tibia, and is inserted into the outer surface of the tarsal bone. An extensor longus digitorum pedis\n(40)\tarising from the fascia of the knee, and the anterior surface of the ligaments of that joint. This furnishes a tendon to each of the five toes. The flexor longus digitorum\n(41)\t, arising from the upper extremity of the tibia, and dividing into five tendons inserted into the last joints of the toes. A short extensor arises from the entire anterior surface of the bones of the tarsus : its tendons unite with those of the long extensor. The short flexor arises from the ankle joint, and giving off fleshy fibres to the tendons of the long flexor. There is likewise a special extensor and abductor of the great toe, and a similar one appropriated to the little toe. Both these arise from the ligaments of the tarsus. External and internal interossei muscles are likewise present.\nThe other muscles represented in the adjoining figures are the sphincter ani (42), and a flexor of the tail (43), derived from the transverse processes of the caudal vertebrae.\nThe Teeth. \u2014 The dental apparatus of the Reptilia is so widely different in its construction in the different orders and even genera of this class of animals, that no general description of it is possible. We shall therefore quote Professor Owen\u2019s * account of the various arrangements adopted in the principal groups into which they have been divided by naturalists.\nIn the Deirodon scaber, the inferior spinous processes of certain of the cervical vertebrae are unusually prolonged, and penetrate the\n* Owen\u2019s Odontography, page 179, et seq.","page":287},{"file":"p0288.txt","language":"en","ocr_en":"288\nREPTILIA.\ncoats of the oesophagus : their extremities, which are thus introduced into the alimentary canal, are coated with a layer of hard dentine, and form substitutes for the teeth, which, if not always entirely absent, are merely ru-dimental in the ordinary situations in the mouth.\nIn the tortoises and turtles the -jaws are covered, as is well known, by a sheath of horn, which in some species is of considerable thickness, and very dense ; its working surface is trenchant in the carnivorous species, but variously sculptured and adapted for both cutting and bruising in the vegetable feeders.\nThe development of the continuous horny maxillary sheath commences, as in the parrot tribe, from a series of distinct papillae, which sink into alveolar cavities, regularly arranged (in Trionyx) along the margin of the upper and lower jaw-bones. These alveoli are indicated by the persistence of vascular canals long after the originally separate tooth-like cones have become confluent and the horny sheath completed.\nThe teeth of the dentigerous Saurian and Ophidian reptiles are, for the most part, simple, and adapted for seizing and holding, but not for dividing or masticating their food.\nIn no reptile are the teeth reduced to so small a number as in certain mammals and fishes, nor are they ever so numerous as in many of the latter class. Some species of Monitor ( Varanus) with sixteen teeth in the upper and fourteen in the lower jaw, afford examples of the smallest number in the present class. It is rarely that the number of teeth is fixed and determinate in any reptile so as to be characteristic of the species.\nThe teeth may be present on the jaws only, as in the Crocodiles and many Lizards; or upon the jaws, and roof of the mouth, and here either upon the pterygoid bones, as in the Iguana, or upon both palatine and pterygoid bones, as in most serpents. As a general rule, the teeth of reptiles are anchy-losed to the bone which supports them. When they continue distinct, they may be lodged either in a continuous groove, as in the extinct Ichthyosaur, or in separate sockets, as in the Crocodilians. The base of the tooth is anchylosed to the walls of a moderately deep socket, in the extinct Megalosaur and Thecodon. In most Ophidians, and in the Geckos, Aganuans, and Varanians, the base of the tooth is imbedded in a shallow socket, and confluent therewith. In the Scincoidians, Safe-guards (Tejus), in most Iguanians, in the Chameleons, and most other Lacertian reptiles, the tooth is anchylosed by an oblique surface extending from the base more or less upon the outer side of the crown to an external alveolar plate of bone, the inner alveolar plate not being developed.\nThe lizards which have their teeth thus attached to the side of the jaw are termed Pleurodonts. In a few Iguanians, as the Istiures, the teeth appear to be soldered to\nthe margins of the jaws: these have been termed Acrodonts. In some extinct La-certians, as the Mososaur and Leiodon, the tooth is fixed upon a raised conical process of bone.\nThe completion of a tooth is soon followed by preparation for its removal and succession. The facility of developing new tooth germs seems to be unlimited in the present class, and the phenomena of dental decadence and replacement are manifested at every period of life. The number of teeth is generally the same in each successive series, and the difference of size presented by the teeth of different and distinct series is considerable.\nThe new germ is always developed, in the first instance, at the side of the base of the old tooth, never in the cavity of the base : the crocodiles form no exception to this rule. The poison fangs of serpents succeed each other from behind forwards ; in almost every other instance, the germ of the successional tooth is developed at the inner side of the base of its predecessor.\nAs the tooth acquires hardness and size, it presses against the base of the contiguous attached tooth, causes a progressive absorption of that part, and finally undermines, displaces, and occupies the position of its predecessor.\nIn the crocodile the tooth-germ is developed from the vascular membrane covering the base of the internal wall of the socket. It is soon invested by a capsule, and by its pressure causes the formation of a shallow recess, or secondary alveolus, in the contiguous bone. In this alveolus, however, it never becomes inclosed like the successional teeth in most mammalia ; for, exerting equal pressure against the fang of the contiguous tooth, which, from being incompletely formed, has a wide pulp cavity with very thin walls, the nascent tooth soon penetrates that cavity, and quits the recess in the alveolar plate, in which it was originally situated. Thus the stage of development corresponding with the eruption of the tooth in the mammalia is immediately followed by the inclusion of the new tooth in the pulp cavity of its predecessor. The rapid succession of tooth germs, which stamps the impress of decay upon their predecessors often before the growth of these is completed, though common to many reptiles, is most strikingly manifested in the crocodiles, in which three and sometimes four generations of teeth, sheathed one within the other, are contained in the same socket.\nThe order Ophidia, as it is characterised in the system of Cuvier, requires to be divided into two sections, according to the nature of the food, and the consequent modification of the jaws and teeth. Certain species, which subsist on worms, insects, and other small invertebrate animals, have the tympanic pedicle of the lower jaw immediately and im-moveably articulated to the walls of the cranium. The lateral branches of the lower","page":288},{"file":"p0289.txt","language":"en","ocr_en":"REPTILIA.\njaw are fixed together at the symphysis, and are opposed by the usual vertical movement to a similarly complete maxillary arch above : these belong to the genera Amphisb\u0153na and Anguis of Linn\u00e6us. The rest of the Ophidians (true serpents), which form the typical members, and by far the greatest proportion of the order, prey upon living animals of frequently much greater diameter than their own ; and the maxillary apparatus is conformably and peculiarly modified to permit of the requisite distention of the soft parts surrounding the mouth, and the transmission of their prey to the digestive cavity.\nThe two superior maxillary bones have their anterior extremities joined by an elastic and yielding fibrous tissue, with the small and single intermaxillary bone ; the symphysial extremities of the lower maxillary rami are connected together by a similar tissue, allowing of a still wider lateral separation. The opposite or posterior extremity of each ramus is articulated to a long and moveable vertical pedicle, formed by the tympanic or quadrate bone, which is itself attached to the extremity of a horizontal pedicle formed by the mastoid bone, so connected as also to allow of a certain yielding movement upon the cranium. The palatine and pterygoid (d) bones have similar loose and moveable articulations, and concur with the other dentigerous bones of the mouth in yielding to the pressure of the large bodies with which the teeth may have grappled.\nWith the exception of the Deirodon scaber and some congeneric species, in which the teeth of the ordinary bones of the mouth are so minute as to have been deemed wanting, the maxillary and premandibular in all true Ophidians are formidably armed with sharp-pointed teeth ; there is on each side the palate a row of similar teeth supported by the palatine and pterygoid bones. In the great Pythons, and some species of Boa, the intermaxillary bone also supports teeth.\nAll the teeth, whatever be their position, present a simple conical form ; the cone being long, slender, and terminated by an acute apex ; and the tooth is either straight, or more commonly bent a little beyond the base, or simply recurved, or with a slight sigmoid inflection. The teeth are thus adapted for piercing, tearing, and holding, and not for dividing or bruising. In some species, certain teeth are traversed by a longitudinal groove for conveying an acrid saliva into the wounds which they inflict : in others, two or more teeth are longitudinally perforated for transmitting venom ; such teeth are called poison fangs, and are always confined to the superior maxillaries, and are. generally placed near the anterior extremity of those bones.\nIn the genus Deirodon the teeth of the ordinary bones of the mouth are so small as to be scarcely perceptible ; and they appear to be soon lost, so that it has been described as edentulous. An acquaintance with the habits and food of this species has shown how admirably this apparent defect is adapted to its\nVOL. iv.\n289\nwell-being. Its business is to restrain the undue increase of the smaller birds by devouring their eggs. Now if the teeth had existed of the ordinary form and proportions in the maxillary and palatal regions, the egg would have been broken as soon as it was seized, and much of its nutritious contents would have escaped from the lipless mouth of the snake in the act of deglutition ; but, owing to the almost edentulous state of the jaws, the egg glides along the expanded opening unbroken ; and it is not until it has reached the gullet, and the closed mouth prevents any escape of the nutritious matter, that the shell is exposed to instruments adapted for its perforation. These instruments consist of the inferior spinous processes of the seven or eight posterior cervical vertebrae, the extremities of which are capped by a layer of hard cement, and penetrate the dorsal parietes of the oesophagus : they may be readily seen, even in very young subjects, in the interior of that tube, in which their points are directed backwards. The shell being sawed open longitudinally by these vertebral teeth, the egg is crushed by the contractions of the gullet, and is carried to the stomach, where the shell is no doubt soon dissolved by the acid gastric juice.\nIn the Boa Constrictor the teeth are slender, conical, suddenly bent backwards and inwards above their base of attachment, with the crown straight curved, as in the posterior teeth. The intermaxillary bone supports four small teeth ; each superior maxillary bone has eight much larger ones, which gradually decrease in size as they are placed further back ; there are eight or nine teeth of similar size and proportions in each pre-mandibular bone. These teeth are separated by wide intervals, from which other teeth similar to those in place have been detached. The base of each of the above teeth is extended transversely, compressed antero-posteriorly, and anchylosed to a shallow alveolus, extending across the shallower alveolar groove. An affinity to the lizard tribes is manifested by the greater development of the outer as compared with the inner wall of the alveolar furrow.\nThe palatine teeth, of which there are three or four in each palatal bone, are as large as the superior maxillary, and are similarly attached : the pterygoid teeth, five or six in number, which complete the internal dental series on the roof of the mouth, are of smaller size, and gradually diminish as they recede backwards. In the interspaces of the fixed teeth in both these bones, the places of attachment of the shed teeth are always visible ; so that the dental formula, if it included the vacated with the occupied sockets, would express a greater number of teeth than are ever in place and use at the same time. In the smaller species of boa the intermaxillary bone is edentulous.\nIn certain genera of the non-venomous serpents, as Dryophis, Dipsas, and Bucephalus,\nv","page":289},{"file":"p0290.txt","language":"en","ocr_en":"290\tREPTILIA.\nin which the superior maxillary teeth increase in size towards the posterior part of the bone, the large terminal teeth of the series are traversed along their anterior and convex side by a longitudinal groove. In the Bucephalus capensis the two or three posterior maxillary teeth present this structure, and are much larger than the anterior teeth, or those of the palatine or premandibular series ; they add materially to the power of retaining their prey, and may conduct into the wounds which they inflict an acrid saliva, but they are not in connexion with the duct of an express poison gland. The long grooved fangs are either firmly fixed to the maxillary bones, or are slightly moveable, according to their period of growth : they are concealed by a sheath of thick and soft gum, and their points are directed backwards. The sheath always contains loose recumbent grooved teeth, ready to succeed those in place.\nIn most of the Colubri each maxillary and premandibular bone includes from twenty to twenty-five teeth ; they are less numerous in the genera Tortrix and Homalopsis, and are reduced to a still smaller number in the poisonous serpents, in the typical genera of which the short maxillary bone supports only a single perforated fang.\nIn the poisonous serpents the superior\nRoof of the mouth of the Rattlesnake, showing the Series of palatine Teeth.\nThe sheath of the poison fang (11), opened to show the poison fang (12). On the opposite side the sheath (10) is represented entire ; h h, external pterygoid muscles ; v v, anterior adductor muscle of the rami of the lower jaw.\nmaxillary bone diminishes in length with the decreasing number of teeth which it supports. The transverse or external pterygoid bone\nelongates in the same ratio, so as to retain its position as an abutment against the shortened maxillary, and the muscles implanted into this external pterygoid style communicate, through it, to the maxillary bone the hingelike movements backwards and forwards upon the ginglymoid articulations connecting that bone with the anterior frontal, and palatine bones. As the fully-developed poison fangs are attached by the same firm basal anchylosis to shallow maxillary sockets, which forms the characteristic mode of attachment of the simple or solid teeth, they necessarily follow all the movements of the superior maxillary bone. When the external pterygoid is retracted, the superior maxillary rotates backwards, and the poison fang is concealed in the lax mucous gum, with its point turned backwards. When the muscles draw forward the external pterygoid, the superior maxillary bone is pushed forwards, and the recumbent fang withdrawn from its concealment and erected.\nThe peculiar structure of the poison fang was first described by Fontana as it exists in the viper, and subsequently received additional elucidation by Mr. Smith\u2019s careful examination of the fangs of the Hydrus, Naja, and Crotalus, and by Mr. Clift\u2019s illustrative drawings appended to Mr. Smith\u2019s Paper. A true idea of the structure of a poison-fang will be formed by supposing the crown of a simple tooth, as that of a Boa, to be pressed flat, and its edges to be then bent towards each other, and soldered together, so as to form a hollow cylinder open at both ends.\nThe flattening of the fang, and its inflection around the poison-duct, commences immediately above the base, and the suture of the inflected margins runs along the anterior and convex side of the recurved fang ; the poison canal is thus in front of the pulp cavity. The basal aperture of the poison canal is oblique, and its opposite outlet is still more so, presenting the form of a narrow elliptical longitudinal fissure, terminating at a short distance from the apex of the fang. The relative position of the two apertures of the poison canal is shown in the figure of the\nFig. 210.\nStructure of the poison-teeth of the Serpent.\na, longitudinal section of poison fang ; b, shows a hair inserted into the poison canal; c, transverse section of fang.","page":290},{"file":"p0291.txt","language":"en","ocr_en":"REPTILIA.\n291\nfang of the large cobra (Jig. 34.), where a fine hair is represented as passing through the poison canal : in figure (a) the relative position of the pulp cavity (x) to the poison canal (y) is shown in the plan of a longitudinal section of a poison fang.\nThe colubriform poisonous serpents of the land have comparatively short venom-fangs, but they are larger than those of the pelagic serpents ; and behind the venom-fangs there are likewise some smaller grooved teeth in the maxillary bones : there are three such teeth in the Bungarus pama, and five in the Bungarus annulatus. In the Hamadryas, or great hooded poisonous tree-snake of India, the venom-fang is relatively as large as in typical poisonous serpents, but three or four smaller grooved teeth are implanted behind it on the maxillary bone.\nIn the most deadly venom-snakes, as the viper {Berus), the puff adder (Vipera), the asps, or hooded snakes (2Vffjr\u00bb),the rattlesnakes (Crotalus)y the cophias and fer-de-lance ( Tri-gonocephalus), the poison fangs acquire their largest size, and are associated only with their successors : these are clustered in greater or less number behind them, presenting the same structure, but of a size proportionate to their degree of development, and further differing in being loosely imbedded in the thick and wide mucous gum, which likewise conceals the fixed and functional fang in its ordinary position of retraction and repose. This fang is more strongly curved backwards than the ordinary teeth, but its acute and slender apex is frequently bent slightly in the contrary direction, as in the rattlesnake.\nThe poison glands occupy the sides of the posterior half of the head : each consists of a number of elongated narrow lobes, extending from the main duct which runs along the lower border of the gland upwards, and slightly backwards ; each lobe gives off lobules throughout its extent, thus presenting a pin-natifid structure; and each lobule is subdivided into smaller secerning c\u00e6ca, which constitute the ultimate structure of the gland. The whole gland is surrounded by a double aponeurotic capsule (b), of which the outermost and strongest layer is in connexion with the muscles (a), by whose contraction the several c\u00e6ca and lobes of the gland are compressed and emptied of their secretion. This is then conveyed by the duct to the basal aperture of the poison canal of the fang. We may suppose, that as the analogous lachrymal and salivary glands in other animals are most active during particular emotions, so the rage which stimulates the venom-snake to use its deadly weapon must be accompanied with an increased secretion and great distention of the poison glands ; and as the action of the compressing muscles is contemporaneous with the blow by which the serpent inflicts its wound, the poison is at the same moment injected with force into the wound from the apicial outlet of the perforated fang.\nThe duct which conveys the poison, although it runs through the centre of a great\npart of the tooth, is, nevertheless, as we have seen, really on the outside of the tooth, the canal in which it is lodged and protected being formed by a longitudinal inflection of the pa-rietes of the pulp cavity or true internal canal of the tooth. This inflection commences a little beyond the base of the tooth, where its nature is readily appreciated, as the poison duct there rests in a slight groove or longitudinal indentation on the convex side of the fang : as it proceeds, it sinks deeper into the substance of the tooth, and the sides of the groove meet and seem to coalesce, so that the trace of the inflected fold ceases, in some species, to be perceptible to the naked eye; and the fang appears, as it is commonly described, to be perforated by the duct of the poison fang.\nThe poison canal again assumes the form\nFig. 211.\nPoison Apparatus of the Viper ( Vipera Berus, after Brandt and Ratzburg).\na, the muscle inserted into the capsule of the gland ; b, the aponeurotic capsule laid open ; c, the poison gland laid bare ;\u2022 d, capsule of the gum containing the supplementary fangs ; e, a hair passed into the poison duct, and into the poison canal of the fang ; f, g, anterior supplementary fang.\nof a groove near the apex of the fang, and terminates on the anterior surface in an elongated fissure.\nDevelopment of the Teeth.\u2014 In the black alligator of Guiana, the first fourteen teeth in the lower jaw are implanted in distinct sockets ; the remaining posterior teeth are lodged close together in a continuous groove, in which the divisions for sockets are faintly indicated by vertical ridges, as in the jaws of the fossil Ichthyosaurus.\nThe tooth germ is developed from the membrane covering the angle between the floor and the inner wall of the socket. It becomes in this situation completely enveloped by its capsule, and an enamel organ is formed at the inner surface of the capsule before the young tooth penetrates the interior of the pulp cavity of its predecessor.\nThe matrix of the young growing tooth affects, by its pressure, the inner wall of the socket, and forms for itself a shallow recess : at the same time it attacks the side of the base of the contained tooth : then, gaining a more extensive attachment by its basis and increased size, it penetrates the large pulp cavity of the previously formed tooth, either by a circular or semi-circular perforation.\nu 2","page":291},{"file":"p0292.txt","language":"en","ocr_en":"292\tKEPTILIA.\nThe size of this perforation in the tooth and of the depression in the jaw, compared with that of the calcified part of the tooth matrix, proves them to have been, in great part, caused by the soft matrix, which must have produced its effect by exciting vital action of the absorbents, and not by mere mechanical force. The resistance of the Avail of the pulp cavity having been thus overcome, the growing tooth and its matrix recede from the temporary alveolar depression, and sink into the substance of the pulp contained in the cavity of the fully formed tooth. As the new tooth grows, the pulp of the old one is removed : the old tooth itself is next attacked, and the crown, being undermined by the absorption of the inner surface of its base, may be broken off by a slight external force, when the point .of the new tooth is exposed.\nThe new tooth disembarrasses itself of the cylindrical base of its predecessor, with which it is sheathed, by maintaining the excitement of the absorbent process so long as the cement of the old fang retains any vital connexion with the periosteum of the socket ; but the frail remains of the old cylinder, thus reduced, are sometimes lifted out of the socket upon the crown of the new tooth, when they are speedily removed by the action of the jaws.\nNo sooner has the young tooth penetrated the interior of the old one, than.apother germ begins to be developed from the angle between the base of the young tooth and the inner alveolar process, or in the same relative position as that in which its immediate predecessor began to rise ; and the processes of succession and displacement are carried on uninterruptedly, throughout the long life of these cold-blooded carnivorous reptiles\nFrom the period of exclusion from the egg, the teeth of the crocodile succeed each other in the vertical direction ; none are added from behind forwards, like the true molars in Mammalia. It follows, therefore, -that the number of the teeth of the crocodile is as great when the animal first sees the light, as when it has acquired its full size ; and, owing to the rapidity of their succession, the cavity at the base of the fully-formed tooth is never consolidated.\nTongue.\u2014In reptiles the tongue can scarcely be regarded as an organ of taste, and indeed, seeing how little their teeth are adapted for mastication, and how' very generally their prey is swallowed entire, such a sense could hardly be usefully accorded to them. The lingual apparatus is, therefore, variously modified in different genera, and converted into an instrument of prehension in some cases, whilst in others it seems to perform functions, the nature of which is not so obvious.\nIn the Chelonian reptiles the tongue is but little adapted to appreciate savours : it is covered with a thick iug< se membrane, the surface of which in the turtles is smooth, but in some tortoises, as, for example, in the\nTestudo indica, it is remarkably beset with numerous elongated and pointed papill\u00e6.\nFig. 212.\nTongue of the Chameleon partially extended.\na, slender extensible .portion of the tongue ; b, e, its bulbous extremity; d, e,f, prehensile apparatus at the end of the tongue.\nBeneath the mucous membrane which eovers this organ, there exists, in this order, a thick stratum of glandular follicles, whilst others situated beneath the tongue pour out their secretion through numerous ducts situated on each side of the fr\u00e6num linguae. The body of the os hyoides is cartilaginous, and from its extremity a glosso-hyal or lingual bone is prolonged into the substance of the tongue,\nIn those lizards which feed upon vegetable substances, the body of the tongue is fleshy, generally bifid at its extremity, and its surface is papillose. In some instances, as in the Iguana, its apex is tipped with horn. In other genera of lizards, which feed principally on insects, the extremity of the tongue is fissured, and the whole organ is remarkably extensible, forming an apparatus wherewith to catch their insect prey.\nPerhaps in no animal is the tongue more remarkable than in the Chameleon, where by its extraordinary power of extension, and by the rapidity of its movements, it is made to compensate for the extreme sluggishness which characterises the muscular system of that animal. The chameleon, fixed firmly by means of its bifid feet upon the bough of a tree, and concealed as much as possible by adopting the colours of the branches around,","page":292},{"file":"p0293.txt","language":"en","ocr_en":"REPTILIA.\n293\nhas no occasion to move in search of insect prey, but waits patiently until its victims approach sufficiently near to be within reach of its singularly constructed tongue ; which, although ordinarily concealed within the cavity of the mouth, is capable of being elongated until it exceeds in length the whole body of the animal. No sooner does a fly approach within five or six inches of the chameleon, than the tongue is slowly protruded for the length of about an inch, so as to expose its thick fleshy extremity, the end of which is divided into two prominent lips, and copiously lubricated with a thick viscid secretion. The whole tongue is then launched out with a rapidity that is perfectly amazing, to the length of six or seven inches, and a fly glued to its extremity is brought into the creature\u2019s mouth, so quickly that the eye can scarcely follow the movement.\nThe following is Mr. Hunter\u2019s description of the anatomy, of the tongue of the chameleon. \u201c The tongue of the chameleon consists of four parts first, a long basis ; second, a pulpy or bulbous part, at the tip of the tongue ; third and fourth, elongating and contracting parts, which run almost through the whole length.\n\u201c The basis, or bony apparatus of the tongue, consists of an os hyoides and os linguae, somewhat similar to. that of a bird ; therefore there is nothing very remarkable in their construction.\n\u201c The bulbous, or thick part at the end of the true tongue, is that part which is to manage the food when caught ; it is the operator within the mouth, of which it is the pincher or catcher, from its being formed at the end into two opposite points, similar to the elephant\u2019s snout. This surface is rugous, and covered with a gelatinous slime.\n\u201c The basis and true tongue or tip are united by an elongated and contracting medium, which is very extensive. This length of tongue, its extension, and contraction, are very, singular, and, if well understood, most probably very curious.\n\u201c The cause and mode of the contraction of its length are not uncommon. The elongation of the tongue in this animal is perhaps like nothing that we are acquainted with in an animal body.\n\u201c The apparatus for the purpose is a small rounded body which passes from the apex of the os linguae (,glosso-hyal) to the bulbous parts, and then through the centre of the bulb. The part between bone and bulb consists of two different substances ; one a whitish substance, which is the firmest, and appears to be capable of keeping its form: the other is softer and more transparent. That part which passes through the bulb consists only of one substance, and appears to be a sheath for the reception of the os-lingu\u00e6.\n\u201c The first of these (i. e. the whitish firmer substance) appears to be composed of rings, or something similar, placed obliquely in con-\ntrary directions, so as to appear to be two spirals crossing one another. Whether the other, or softer substance, has any direction of fibres, I could not observe, but I suspect it is muscular. If I am right in my conjecture, and of its disposition, it will be no difficult thing to show how it may be elongated ; for if these rings are placed transversely, they may be brought so near to one another as to shorten the whole very considerably ; and if they allow of being placed almost longitudinally, they must of course lengthen it very considerably ; and this position can be easily produced by muscles, which I take the pulpy substance to be.\n\u201c The contraction of the tongue is owing to a degree of elasticity, but this appears to be only in the cellular membrane, acting as an assistant to the muscular. The muscular contraction is owing to two muscles, one on each side of the tongue : each arises from the os hyoides, on the inside of the os linguae, and passes along the side of the tongue to its bulbous part ; but before it gets to the bulbous part, it spreads itself all round.\n\u201cIn the centre of each of these two muscles passes a considerable nerve to the bulbous part, and also two arteries. When the two muscles act, they draw the tongue back upon the os-lingu\u00e6, which, as it were, passes through the middle elongator, then through the centre of the bulb, till the whole tongue is retracted. Although this middle body is drawn upon the os-linguse, yet it does not appear to be hollow, like a pipe; it rather appears to be filled with a very ductile cellular membrane, as in every part of the elongating division of the tongue, in order to allow of the great difference in the situation of parts with respect to one another.\u201d\nIn the Crocodiles, the structure of the tongue is equally remarkable, but of a very different character. In these reptiles the tongue has no projecting or moveable extremity, being attached by its whole circumference to the rami of the lower jaw, insomuch that it was described by Aristotle us being entirely deficient. Its whole surface is covered over with a thick coriaceous skin, upon, which may be seen the openings of innumerable glandular follicles situated beneath it. At the posterior part of the organ, close to the opening of the fauces, the broad anterior part of the hyoid cartilage supports a broad fold of the skin that covers the tongue, which can be applied like a valve against a corresponding fold of the palatal membrane that descends from the roof the mouth, so that the two, when approximated, form a valve that completely closes the communication between the mouth and the posterior fauces. By this arrangement the crocodile is enabled to keep its mouth open under water without danger of suffocation from that fluid getting into its trachea, whilst by means of its long tubular nostrils, which open at the very apex of its snout, and are continued^ackwards to behind the valvular apparatus above described, it is enabled to\nu 3","page":293},{"file":"p0294.txt","language":"en","ocr_en":"REPTILIA.\n294\nbreath with facility whilst only the tip of its\nFig. 213.\nThroat, (Esophagus, and Stomach of the Crocodile.\na, nostrils ; b, postorbital plate ; c, tongue ; d, valves of the fauces; e, oesophagus; f muscular portion of stomach ; i, central tendons of ditto ; g\u2014k, commencement of duodenum.\nnose is above the surface of the water, {fig. 213.)\nDigestive System. \u2014 The oesophagus of reptiles is never dilated into a crop, as in birds ; it either preserves nearly the same diameter throughout its entire length, or, if its capacity\nvaries, it is insensible, and not by any sudden dilatation. But its diameter is generally much greater relative to the stomach, than in Mammalia or birds. In the Ophidians it is even more capacious than the stomach, at least when the latter is not distended with food : this happens because the walls of the stomach are more muscular than those of the oesophagus, and, consequently, contract more forcibly. When the oesophagus gradually dilates as it approaches the stomach, it often becomes difficult to say where one terminates and the other begins, and, consequently, to assign the situation of the cardia. The stomach is generally without any cul-de-sac, and its form much elongated. Most reptiles living upon prey have the digestive apparatus, and more particularly the stomach, of carnivorous animals. The latter viscus is always single, never multiple ; its cavity being simple, never complicated. Even in those reptiles that feed on vegetable substances, the same plan of organization is retained, very slightly modified by such opposite habits.\nThe oesophagus of some Chelonian reptiles\nFig. 214.\nHorny Processes in (Esophagus of Turtle.\npresents internally its whole inner surface crowded with long, hard, conical papillae {Jig. 214.), the points of which are directed backwards towards the stomach, and doubtless serve to prevent the return of substances swallowed towards the mouth. The muscular coat is generally very strong.\nThe stomach is generally of an elongated form and cylindrical shape ; its longest portion is directed backwards ; it then suddenly bends at an angle, and runs forwards. The second portion, which terminates at the pylorus, is always shorter than the first ; its muscular coat is thicker than in the cardiac portion, and its lining membrane here forms longitudinal folds, which are more numerous and distinct. The pylorus is indicated by a circular elevated ring, which is sometimes very thick, or else by a fold.\nGenerally the walls of the stomach in the Chelonian reptiles are thick, partly owing to the strength of the muscular tunic, partly to the thickness of the mucous and cellular coats, the latter being penetrated by numerous crypts.","page":294},{"file":"p0295.txt","language":"en","ocr_en":"REPTILIA.\t295\nThe stomach is closely connected with the liver, and in some species, as, for ex-\nFig. 215.\nDraco volans.\na, ventricle of the heart ; b, the right auricle ; c, the left auricle -, d d, carotid arteries ; e e, the vena jugularis ; Jf, the subclavian artery ; g, the trachea ; h, the right lung ; i, the left lung ; k, the liver ; 11, the lower venous sinus, which commences from the liver and extends to the right venous sinus ; m, the biliary duct; o, the stomach; p, the commencement of the small intestine ; q q q, the windings of the small intestine ; r, the commencement of the large intestine; s, its attenuated region; tt, the kidneys ; u, the cloaca ; v, the bladder ; w, the anus.\nample, in Fmys concina, absolutely imbedded in its substance.\nThe diameter of the small intestine in the Chelonians gradually diminishes from the pylorus to its termination in the large intestine, the diameter of which is much larger, and its extremities much thicker. The parietes of the whole intestinal canal are indeed thicker than in most other reptiles. The calibre of the intestine is uniform throughout, and its lining membrane presents folds of variable breadths in different species, which are generally united together so as to form a kind of net-work at the commencement of the small intestine, but subsequently these become longitudinal and parallel. In the large intestines these folds become less regular in their arrangement.\nIt may be added to the above general description, that the alimentary canal of the\nreptiles belonging to this order presents ences in each genus, and even in some species of the same genus, which are in relation with corresponding differences in the nature of their food. The tortoises and the turtles, which live principally upon herbs or fuci, have the intestinal canal long ; the large intestine longer than the small ; the latter being inserted into the former laterally, so as to leave a small c\u00e6cum behind the point of entrance.\nIn the different species of Emydes, which are more carnivorous in their habits, and in the Trionyx, the alimentary canal is shorter \u2014 at least the large intestine, which is not longer than the small; and the latter is continuous with the large intestine, without there being any insertion of one into the other.\nThe Crocodilid\u0153 differ from all other saurian reptiles in the form of their oesophagus and stomach.\nThe oesophagus is a narrow canal, easily distinguishable from the stomach on account of the globular form of the latter, and also by the different structure of mucous and cellular coats, the former of which iS plicated and villous in the oesophagus, while the latter is very thin, and hardly perceptible.\nThe stomach is a great rounded globular cul-de-sac {fig. 213.),into which the oesophagus opens, at no great distance from the pylorus.\nClose to this insertion there is, inferiorly, a small cul-de-sac (g), the cavity of which is separated from the larger cul-de-sac by a narrow passage, and which opens into the intestine by a~ constricted orifice. Necessarily, alimentary substances must pass through this channel into the pyloric cul-de-sac, in order to escape from the stomach. This structure evidently corresponds to the pyloric portion of the stomach in ophidian reptiles, to be described hereafter.\nGenerally, the parietes of the stomach are very strong; the mucous lining is smooth, thick, and very glandular, forming here and there broad folds, which run in a serpentine manner, like the convolutions of the brain. The cellular tunic, which was not very distinct in the oesophagus, becomes so in the stomach, whilst the muscular coat almost equals in thickness that of the cellular and mucous tunics combined : it is principally composed of fasciculi, which radiate from the centre towards the circumference, arising from an aponeurotic disc, which exists on both the abdominal and dorsal aspects of the organ. This stomach very nearly resembles the gizzard of a bird ; and the resemblance becomes more striking if it be compared with the gizzard of a heron, the walls of which are thin, and which also opens into a little appendage.\nThe small intestine in the Nilotic crocodile may be distinguished into two portions : the first of these is wide, with thin walls, and is bent four times upon itself, so as to make four permanent folds : this portion is equal in length to about four-tenths of the whole\nu 4","page":295},{"file":"p0296.txt","language":"en","ocr_en":"296\tREPTILIA.\nlength of the intestine, and corresponds to the duodenum of birds. The other part is of smaller diameter, and has thicker walls, enclosing between the mucous and muscular tunics a layer of glandular substance, resembling a greyish, semitransparent pulp. The lining membrane of the intestine which covers this glandular layer is disposed in longitudinal zig-zags, connected together by little folds that pass from one to another, so as to constitute a fine net-work. These zig-zags are replaced by delicate villosities in the first portion of the small intestine, where the glandular layer is not perceptible ; and towards its termination in the large intestine, they become reduced to undulating folds, rarely joined together by transverse plicae. In the larger intestine itself, they are converted into irregular projections, which form a sort of villous surface.\nIn the other families of saurian reptiles, the form and structure of the stomach may be referred to the common type which we have already seen in the Chelonians. The oesophagus is wide, with very extensive walls, as is indicated by the longitudinal folds of its lining membrane ; it is generally of the same diameter with the stomach, which latter forms a cylindrical or conical bowel, directed from before backwards, and generally bent a little towards the right near its termination, so that we may distinguish a pyloric portion extending from the bend to the pylorus, the length of which is very variable, and which is distinguishable from the rest of the stomach by the greater thickness of its coat. At the entrance of the duodenum there is a prominent muscular ring, serving the office of a pyloric valve.\nThe great curvature, which is generally more dilated, is sometimes, though rarely, prolonged into a small cul-de-sac (Monitor of the Nile).\nThe small intestine of the Lacertid\u0153 is short and sometimes very capacious in the first half of its extent; the other half presents ligamentous bands, which produce puckerings and constrictions corresponding internally with transverse ridges that intersect the oblique folds of the lining membrane. This latter in the large intestine forms transverse valves, dividing its cavity into numerous pouches.\nThe Iguanas, which live entirely upon fruits, grains, and leaves, have no c\u00e6cum, properly so called, indicative of this regimen ; but their large intestine is prodigiously developed, and its cavity extended by numerous internal folds of the lining membrane.\nIn the Ophidian reptiles, the oesophagus and stomach form a continuous canal of variable length, in which it is generally difficult to say where the one terminates and the other begins ; it may be remarked, however, that the walls of the oesophagus are thin, and the longitudinal folds of its lining membrane small and few in number, whilst the commencement of the stomach is indicated externally by a strengthening of the muscular fasciculi, and internally by thicker and more numerous longitudinal plicae of the lining tunic, which\nare often undulating, and here and there irregular. These folds are only visible when Fig. 216.\nAlimentary canal of Draco viridis.\na, tongue ; b, larynx ; c, opening leading into the guttural sac; d, laryngeal sac, e, oesophagus; f, stomach ; g, g, small intestine ; h, c\u00e6cal appendage to the commencement of the colon ; i, colon ; k, the cloaca.\nthe stomach is empty. Sometimes the cardiac commencement of the stomach is indicated by a kind of cul-de-sac.\nThe stomach of serpents is remarkably short in relation to the length of the animal and the extent of the oesophagus; its situation also is very far back, so that the prey which the animal swallows will be lodged partly in the oesophagus and partly in the stomachal cavity. The latter may be divided into two portions, one of which Cuvier calls the \u201c sack \u201d and the other the pyloric portion. The \u201c sack \u201d has a very different appearance when empty to that which it presents when distended with prey : in the first case, its walls appear thick and muscular, whereas in the second they are very thin and extensible.\nBefore terminating in the intestine, the stomach becomes considerably diminished in its diameter, and is converted into a narrow channel of valuable length in different genera and even in different species, which is but little susceptible of dilation, and into which the food only passes after being digested in the first portion. This second division of the stomach may be continuous with the axis of the former; at other times it seems to be given off from one side. It may be more or less bent upon itself, or even form several curvatures in different directions, or pass straight into the intestine. When the stomach","page":296},{"file":"p0297.txt","language":"en","ocr_en":"REPTILIA.\t297\nis empty, the pyloric portion may be distinguished from the \u201c sack \u201d by the thinness of its walls and the absence of longitudinal folds in its mucous membrane, which latter become gradually obliterated as they approach the pylorus. At its termination, this portion of the stomach can hardly be distinguished from the commencement of the intestine, which it resembles both in the transparency of its coats and, in its uniform diameter ; generally, however, the walls of the intestine are thinner and more transparent than that of the pyloric portion of the stomach, and its diameter sensibly increased. Internally, there is a very perceptible difference in the structure of the mucous membrane lining the two, which, in the pyloric portion of the stomach, is arranged in small longitudinal rugae, but in the duodenum has a shaggy or villous appearance. Generally there is a valve or circular fold separating the stomach from the intestine, but this is sometimes only represented by a prominent ring formed by the mucous and cellular coats, and occasionally is altogether wanting.\nIt is in that part of the stomach which Cuvier calls the \u201c sack \u201d that the digestion of food is accomplished. The pyloric portion forms a first obstacle to stop the prey, which descends to the bottom of the stomachal \u201c sack,\u201d where the digestive process is most rapidly carried on, for it is here that the dissolution of the animal swallowed always commences. In proportion as this dissolution goes on, the pyloric canal, the diameter of which is always very small, allows the digested portions of food to pass successively into the intestine.\nThe intestinal canal in the common or ring-snake runs in an undulating manner from the pylorus to the rectum, preserving pretty nearly the same diameter throughout its whole extent, except that it dilates a little to form the colon. The lining membrane of the small intestine forms broad longitudinal laminae, folded like a shirt-sleeve. In the large intestine, which runs straight to the cloaca, the folds are thick and irregular.\nIn the true serpents the arrangement is different : the first portion of the intestine forms numerous loops, more or less closely bent upon each other, and retained in position by bands of peritoneum passing between them. The whole is enveloped in a long cylindrical cell formed by the peritoneum.\nThis disposition of a part of the alimentary canal in the true serpents, distinguishes them from all other vertebrate animals ; it seems to be rendered necessary by their manner of progressing upon their belly, which, without this precaution, might injure their intestines : it must, how'ever, render slower the peristaltic movements, and thus contribute to produce the extreme lentor of all their digestive functions. This seems to be proved by the fact, that in water serpents (Hydrus, Platurus, Chersydrus') the intestine is a continuous cavity, and not divided into several loops, their movement in the water not requiring such arrangement.\nIn the Ophidian reptiles we may always distinguish a large and a small intestine ; the\nFig. 217.\nViscera of the Rattlesnake, a, the trachea ; b, the right lung ; c, bladder-like termination of ditto ; d, e, f, the oesophagus ; g, the stomach ; h, commencement of the intestine, 1 ; l, the heart ; m, large arterial trunks ; n, n, anterior and posterior ven\u00e6-cav\u00e6 ; o, the liver ; p, the gallbladder, situated at some distance from the liver.\nlatter generally terminates end to end in the former, and it is rare to find anything like a cul-de-sac or c\u00e6cum at the place of their union. The small intestine preserves nearly the same diameter throughout. The large intestine, which is shorter, is generally divided into two or sometimes three compartments by one or more sets of valves, or even by one or two partitions, through which there is only a small opening leading from one compartment to another. The first compartment is generally smooth, or only presents internally a few simple folds ; whilst the last compartment, or the rectum, properly so called, has its cavity divided by irregular transverse plicae, or even by very broad valvulae conniventes. When there is an intermediate compartment, its sides are","page":297},{"file":"p0298.txt","language":"en","ocr_en":"298\tREPTILIA.\nsmooth, or nearly so, like the first ; but the communication between it and the third is always very narrow. Generally speaking, every arrangement seems to have been made to retard the passage of alimentary substances, and of the residue of digestion ; or at least to prevent their passage from being too much accelerated by the act of creeping, and the contractions of the abdominal muscles necessary for its performance. The lining membrane of the small intestine is thrown into longitudinal folds of variable breadth, and more or less thick and numerous, which extend throughout its whole length, but which sometimes are connected together by transverse bands, so as to form cells. Sometimes these folds are beautifully fringed in the first portion, so as to give the mucous lining a villous appearance ; and they have been observed quite white, with chyle filling their lacteal vessels.\nThe liver of reptiles is but indistinctly divided into lobes, and frequently is only irregularly notched upon its free border. Its relative size, in this class of animals, is very considerable. When the body is broad, it occupies a large proportion of both the hypochondriac regions ; but when the body is elongated, it is situated in the right hypo-chondrium only, but extends very far back by the side of or beneath the intestines, in which position it is maintained by folds of peritoneum, resembling those which form the air-cells of birds.\nIn the Chelonians the liver is divided into two rounded irregular masses ; one of which fills the right hypochondrium, whilst the other, which is connected with the smaller curvature of the stomach, extends into the epigastric and left hypochondriac regions : these two divisions are only connected together by two narrow processes, which bound a space through which the principal hepatic vessels pass.\nIn the crocodiles, whose digestive organs, in many respects, resemble those of birds, the liver consists of two distinct lobes, united together by a narrow central portion.\nIn the spectacled Ca\u00efman (Crocodilus scle-rops), the right lobe is the largest, whilst the left is small and triangular. These two lobes separate anteriorly to receive the heart. The gall-bladder is always connected with the right lobe, but is here quite detached and separate from it,\u2014a circumstance which holds good likewise in the Gavials ; whilst in the Crocodile it is closely connected with the right lobe.\nAmong the Lacertid\u0153, the monitors have likewise two lobes to their liver, which are separated by a deep fissure. In the safeguards (Ameiva) this fissure is less decided, and the right portion of the viscus is prolonged backwards to a long, narrow, pointed appendage. This form conducts us gradually to the shape of the liver most generally met with in other Saurians, in which the organ consists of a single mass, rarely divided by deep fissures, but slightly notched at its mar-\ngin. This mass is generally of a triangular shape, which is lengthened out in accordance with the form of the body, sometimes extending backwards quite to the posterior boundary of the abdominal cavity. In the Ophidian reptiles the liver is not divided into lobes, but forms a long cylindrical mass.\nThe gall-bladder is, in the Chelonian reptiles, almost entirely imbedded in the right lobe ot the liver, and is generally of very great size ; whilst in the Saurian reptiles it is generally situated at the bottom of the fissure which separates the two lobes. In the Ophidian reptiles, the position of the gall-bladder varies ; in the genera Anguis, Am-phisboema, and Cecilia, it is more or less in-crusted by the substance of the liver; but, in the true serpents, its position is very remarkable, for it is not only entirely separated from the liver, but is removed to a considerable distance from that viscus, and placed in the immediate vicinity of the pylorus.\nIn all reptiles the bile is conveyed into the gall-bladder by the branches of the hepatic ducts, which open either into its fundus, its neck, or into the commencement of the cystic canal : in the Chelonians, a very large proportion of the bile would seem to pass through the gall-bladder. In the Tortoises, which have the gall-bladder imbedded in their liver, the hepato-cystic vessels open immediately into its cavity. In the Emydes, the hepatic ducts unite to form a canal, which joins the neck of the gall-bladder.\nAmongst the Crocodiles, the spectacled ca\u00efman has its bile-ducts arranged almost in the same manner as in birds ; the right hepatic canal opening immediately into the gallbladder.\nIn the other Saurians, and also in Ophidian reptiles, the hepatic duct unites with the cystic, so that the gall-bladder is filled by the reflux of the bile; generally, there is only one hepatic duct, but in other cases there are several, which enter the cystic duct near the neck of the gall-bladder, as, for instance, in Trigonocephalus.\nThe pancreas is present in all reptiles, and is generally situated close to the point where the stomach terminates in the intestine, to which it is most generally adherent. In the Chelonians its shape is irregularly triangular, being narrow and thin in the vicinity of the pylorus, broad and bifurcated at its opposite extremity, by which it adheres to the spleen and to the large intestine. In the Saurians it is generally placed close to the pyloric portion of the stomach, and is divided into two branches, one of which accompanies the biliary canal ; the other adheres to the spleen. These two branches unite in the vicinity of the pylorus, and furnish a duct which opens into the intestine along with that of the gall-bladder, which not unfrequently is imbedded in the substance of the pancreas. A similar disposition occurs in all the Ophidian genera.\nThe spleen is in the Reptilia always present, but its relations with the stomach 'are by no means so constant as in birds and Mammalia.","page":298},{"file":"p0299.txt","language":"en","ocr_en":"KEPTILIA.\n299\nFig. 218.\nViscera of the Female Tortoise. (Emys Eu.rop\u00e6us.') The Lungs and Lymphatic Vessels have been removed, to exhibit the Course of the principal Blood Vessels.\nA, arch of the right aorta ; b, arch of the left aorta ; c, the pancreas ; e, trachea ; e', e', right and left bronchus ; f/, f>, right and left subclavian arteries ; H, the clitoris, lodged in the cavity of the cloaca, showing the deep urethral groove running along its dorsum ; i, i', lobes of the liver ; k, k/, the stomach ; L, common trunk formed by the union of the right and left aorta ; M//, m', m', the right and left oviducts ; N, the ovarium ; Q, termination of the urethral groove, at the extremity of the clitoris u, u, supernumerary lateral bladders, opening by wide fissures into the cloaca on each side of the clitoris ; u', urinary bladder ; x, the spleen ; d, vena-cava inferior, opening into the right auricle of the heart ; e1, g, h, i, trunks of the jugular and subclavian veins.\nIt is frequently connected with the commencement of the intestinal canal. This is the case in the Chelonian reptiles (fig. 218. x.), it is fixed to the duodenum, not far from the pylorus, behind the opening of the ductus communis choledochus, and the head of the pancreas (c). In the Trionyx it, together with the head of the pancreas, is inclosed between the layers of the mesentery ; and in the Turtle is contained in the first loop formed by the duodenum, close to the pylorus. In the Crocodile of the Nile it is attached to the left side of that portion of the intestine which immediately succeeds the first loop ; whilst in the Ca\u00efman it is placed between the layers of the mesentery adhering to the second intestinal\nloop, close to the pancreas. In Lizards its usual position is at the side of the stomach.\nThe spleen in Ophidian reptiles. belonging to the genera Anguis and Cecilia, is situated rather behind than in front of the pancreas, close to the commencement of the intestine ; but in all the true serpents it is situated in front of the pancreas, to which it is closely attached, or indeed sometimes imbedded in its substance, receiving from it numerous veins of large size, which sometimes appear to form a sinus between the two organs, which are moreover connected by fibrous bands, and bound down by the same folds of peritoneum.\nThe abdominal viscera of reptiles are retained in situ by numerous mesenteric folds, the","page":299},{"file":"p0300.txt","language":"en","ocr_en":"REPTILIA.\n300\narrangement of which varies in different races. It must be remembered that throughout the entire class there is no diaphragm or other septum dividing the viscera of circulation and respiration from those of digestion, all being inclosed in a common cavity, lined by the pleuro-peritoneum, which gives off processes to inclose and to fix them as far as is necessary in their respective situations. In the tortoises, that portion of the mesentery which attaches the small intestines, does not come immediately from the vertebral column, and only forms the mesentery after having fixed the transverse colon by a meso-colon. This remarkable disposition depends upon the general arrangement of the pleuro-peritoneum, and the extent of the cavities that it forms for the lodgment of the lungs. The meso-rectum also is derived rather from the lateral regions of the pelvis than from its middle. There are, besides hepato-gastric laminae, which pass from the liver to the stomach, hepato-duodenal laminae, between the liver and the duodenum ; transverse gastro-colic laminae, which pass from the stomach to the transverse portion of the large intestine ; and duodeno-colic layers connecting the duodenal loop with the ascending colon. On the right of the mesorec-tum, there is an expansion which descends from the dorsal portion of the abdominal walls to join the proper mesentery.\nLastly, the large intestine commences by a loop which is bound down by peritoneal laminae.\nIn the Saurian reptiles, the mesentery is well developed, that portion wrhich is connected with the large intestine, as well as that which sustains the small intestine, coming off from the vertebral column. There is no transverse mesocolon.\nThe pleuro-peritoneum of Ophidian reptiles presents some varieties in its disposition. In the Anguid\u00e6, a mesentery is given off from the whole length of the front of the vertebral column anteriorly : this serves to suspend the oesophagus and stomach, furnishing likewise a mesenteric fold to each lung, and to the liver. After enveloping the liver it forms a suspensory ligament attached to the mesial line of the ventral aspect of the abdominal walls, so that the whole may be regarded as forming two bags connected together, both above and below, along the middle line of the body, and thus dividing the abdominal cavity into two compartments by a vertical septum, extending along its whole length.\nIn the Cecili\u00e6 a similar disposition exists.\nIn the true serpents the pleuro-peritoneum forms a cell around the intestine, which contains likewise small omental folds loaded with fat : the intestine itself, moreover, is folded into numerous festoons connected to each other by fibro-cellular bands. The large intestine in serpents has no connexion with the stomach, or with the commencement of the intestinal canal, as is almost invariably the case in other vertebrata.\nLymphatic System.\u2014The lymphatic vessels in reptiles appear to be completely destitute of\nvalves, except at the points where they terminate in the veins; a circumstance which explains the facility with which they can be injected from trunk to branch.\nIn the Chelonian reptiles the lymphatics of the alimentary canal, especially those of the stomach and small intestine, form two principal layers, of which the inner one constitutes a very delicate net-work *, so thin as only to be well seen with a magnifying-glass, lying close to the inner surface of the intestine, interlaced amongst the blood-vessels, but easily distinguishable from their continuity.\nThe external layer is made up of larger branches, which are so numerous that they touch each other, and after a successful injection completely cover the intestine : they all affect a longitudinal direction, and have an undulated or wavy appearance.\nThe lymphatics of these two layers serve to form another net-work placed external to the last, made up of large confluent branches, which convey the lymph into the principal lacteal trunks of the mesentery, which latter form a fourth net-work, the meshes of which are very close and fine.\nIn the urinary bladder and the oviduct, the arrangement of the lymphatics is similar to the above.\nIn the lungs they form a superficial layer, made up of large trunks ; and a deep-seated layer, composed of very fine branches.\nThe external net-work of the gall-bladder is made up of very small meshes ; whilst that of the spleen, on the contrary, consists of large confluent trunks, resembling sinuses : the latter organ, however, has likewise a smaller deep-seated set of lymphatic vessels which accompany the ramification of the veins into its interior.\nThe lymphatics of the testicle have a ramified or arborescent arrangement, increasing in size as they pass from the outer to the inner margin of the organ, the branches forming numerous anastomoses amongst themselves.\nThe adipose tissue, situated between the peritoneum and the carapax, is full of lymphatic vessels. Those of the peritoneum are very small and numerous : their direction is generally from before backwards.\nThe liver seems to possess very few lymphatics, and these Panizza was unable to inject, as also those of the oesophagus.\nAmong the Saurian reptiles the lymphatics have been examined in the Ca\u00efman, and in several species of lizards. In the former, the cloaca, the rectum, and the intestinal canal inclose several net-works of lymphatic trunks, the form and disposition of which varies. There is one upon the inner surface, and another upon the outer surface, the meshes of which are very close, and the vessels much convoluted.\nIn the rectum, the lymphatics form two layers, one superficial, the other deep-seated ; in the former the vessels are large and their\n* Panizza Sopra il Sistema Linfatico dei Rettili, &c. Pavia, 1833. in fol. with six plates.","page":300},{"file":"p0301.txt","language":"en","ocr_en":"REPTILIA.\t301\ndirection transverse, whilst in the latter the the other superficial, the vessels of which are canals are smaller, and their course longitudi- larger.\nnal.\tThe kidneys also are very rich in lym-\nIn the small intestine, likewise, there are phatics. two layers of lacteal vessels, one superficial The central parts of the lymphatic system (the peritoneal), and the other deep-seated, of reptiles, corresponding with the receptacu-There is, moreover, a third stratum, composed lum chyli and thoracic duct of mammalia, are of very fine lymphatics, which penetrate as extraordinarily capacious. They resemble, in far as the villi of the mucous membrane of fact, great serous cavities which are never the intestine. In the stomach they are com- entirely filled with lymph, but which establish paratively few in number.\ta communication between the lymphatics of\nThe lymphatics of the Jungs form a net- the viscera and other organs, and the veins work, the meshes of which are scattered and situated in front of the heart. These reser-are irregular ; upon the heart they are very voirs embrace the principal arteries, and even numerous, inclosing rhomboidal spaces.\tthe veins that they encounter in their passage,\nIn the green lizard the lymphatics form a covering them as with a sheath {fig. 219, c.). beautiful plexus around the corpus caver- The lymphatics from the different organs, as nosum, and a complicated net-work upon the they run towards these receptacles, form cloaca ; but it is remarkable that Panizza was plexieose chains or detached branches, which not able to inject the lymphatics of the limbs, are more or less knotty in their calibre, nor those of the testicles or kidneys.\tIn the Che/onian reptiles, according to\nIn Ophidian reptiles, the whole extent of Hewson, all the lymphatics derived from the the alimentary canal, with the exception of hinder part of the body terminate in a plexus the oesophagus, is covered with lymphatic which surrounds the right aorta, and from vessels, which are disposed in two layers, one thence open into a reservoir situated further deep-seated, made up of very delicate tubes, forward beneath the left aorta, This latter\nFig. 219.\nViscera of the European Tortoise in situ, seen from behind.\nE the trachea : c c, great central reservoirs of the lymphatic system surrounding the principal arterial and venous trunks; ff, subclavian vessels divided; b h, h h, ii, trunks of the large vessels derived from the arches of the aorta ; i i, lateral margins of the liver ; z z, the lungs ; o o, the kidneys ; n, external iliac artery; u u, lateral supplementary bladders; vv, urinary bladder dilated transversely; H, the penis retracted into the cloaca ; r, termination of the urethral groove. {After Bojanus.)","page":301},{"file":"p0302.txt","language":"en","ocr_en":"302\tREPTILIA.\ngives origin to two thoracic ducts, or rather to several principal trunks, which, as they advance, form two complicated plexuses, extending as far as the subclavian veins on each side, where they receive the lymphatics of the head, neck, and anterior extremities. On the right side, two branches pass from the plexus to open into the jugular vein, near its junction with the subclavian ; on the left side there is only a single lymphatic trunk, which opens into the jugular near the same point.\nAmong the Saurian reptiles the arrangement of the lymphatic system is as follows. In the pike-headed Caiman, there is a sacral plexus formed by the lymphatic vessels derived from the tail, and the posterior extremities under the vertebra, which represents the sacrum ; this plexus is continued along the aorta and the vena cava, the former vessel being in some places quite inclosed by it : this forms the principal reservoir of the lymphatic system. Opposite the third and fourth lumbar vertebrae, this reservoir receives the anterior trunks derived from the lateral pelvic plexuses, as well as those of the kidneys and of the loins ; it then runs forward and slightly to the left side, above the vena cava, where it receives the lymphatics of the mesenteric plexus.\nArrived opposite the conjunction of the two aort\u00e6, this reservoir divides into four trunks, which represent the thoracic duct ; these trunks unite and separate again several times as they advance forward : at last they form two fasciculi of vessels, which separate to the right and left, and terminate in the corresponding subclavian veins, having first received the lymphatics derived from the head and neck and anterior extremities.\nIn the green Lizards, the central reservoir of the lymphatics commences a little in front of the anus, by a cul-de-sac, which receives the lymphatics of the hinder extremities, of the kidneys, and of the rectum ; it then advances forwards in the abdomen, becoming considerably dilated, and .collects the lymphatics of the small intestines, and partly those of the stomach. A little in front of the latter viscus there is a constriction which seems to indicate the limit between the reservoir and the thoracic duct. The latter vessel runs between the oesophagus and the vertebral column ; and afterwards between the latter and the left lung. Arrived at the heart, it divides into two diverging branches, which, running outwards, terminate in the anterior vena cava.\nIn the Ophidian reptiles the central lymphatic reservoir commences in front of the anus, and advances forward inclosed between the layers of the mesentery, between the intestines and the vertebral column ; becoming much enlarged as it advances forwards, and ultimately terminating in a conical cul-de-sac, opposite the commencement of the stomach. This reservoir receives the lymphatics from the tail, from the penis, from the kidneys, the testicles, the intestine, the stomach, and the dorsal region of the\nspine. A little before its termination in the cul-de-sac it gives off several branches, which, united, into a single trunk, form the left thoracic duct. This runs forward between the stomach and liver, and subsequently between the liver and the oesophagus, to arrive at the region of the heart. The inferior or anterior right thoracic duct commences by a narrow cul-de-sac situated just behind the pancreas, and receives the lymphatics of the pancreatic plexus, as well as those from the spleen and gall-bladder. It runs forward above the vena porta and the vena cava; between the layers of the epiploon it receives three considerable branches from the right thoracic duct, and most of the lymphatics of the stomach ; it then expands very considerably to envelope the stomach, and becoming again contracted beyond that viscus, it runs forward beneath the lung as far as the right side of the heart, near the entrance of the vena cava, into the pericardium, where it terminates by a cul-de-sac, after receiving several branches from the lungs.\nThree other considerable lymphatic trunks, one mesial and inferior, the two others lateral, run along the whole length of the body from the head to the base of the heart, conveying into the cardiac plexus the lymph from all the anterior part of the body.\nThe cardiac plexus, which is situated in front of the base of the heart, is formed by the confluence of all the lymphatic trunks, forming as it were a central reservoir, being composed, first, of the three anterior lymphatic vessels mentioned above; secondly, by the left thoracic duct ; and, thirdly, by a trunk which combines the lymphatics of the lung and the right thoracic duct.\nThis reservoir opens into the anterior vena cava.\nThe lymphatic system of reptiles offers one peculiarity of structure which is very remarkable. Besides the usual termination of the principal lymphatic trunks in the ven\u00e6 cav\u00e6 or in the axillary, subclavian, or jugular veins, it has been discovered that some lymphatic trunks open into small capsules which present alternate movements of contraction and dilatation, and which propel the lymph that they contain immediately into small contiguous veins ; these capsules are therefore lymphatic hearts.\nSuch lymphatic hearts have been found to exist, both in the Saurian, Ophidian, and Batrachian orders of reptiles, the Chelonians only appearing to be without them. They are generally situated near the posterior extremity of the body, and discharge into the venous system the lymph derived from the most remote parts.\nIn the crocodile the lymphatic hearts are found on each side lodged between the upper border of the pelvis and the transverse process of the first caudal vertebra. They resemble elongated transparent bladders, and communicate with the veins of the kidney.\nIn the green lizard they occupy a similar situation, but they open into a vesicle that","page":302},{"file":"p0303.txt","language":"en","ocr_en":"REPTILIA.\nempties itself into the principal vein of the corresponding hinder extremity. 3\nThe lymphatic hearts are in the snakes situated just above the origin of the tail. They communicate with a branch of the caudal vein, and receive lymphatic vessels from the posterior extremity of the great lymphatic reservoir.\nIn the Pythons, the situation of the lymphatic hearts is external to the abdominal cavity in a special chamber, which is bounded anteriorly by the last rib ; each heart receives the lymph by three canals that open into its dorsal aspect, and it communicates with the caudal veins by two orifices situated at its anterior extremity. Each of these lymphatic hearts is composed of three membranes ; an external one, which is cellular ; a middle one, which is muscular, the muscular fasciculi being arranged as in the hearts of the higher animals ; and an inner coat, which forms valvular folds, serving to prevent the escape of the venous blood into the lymphatic system.\nThese lymphatic hearts are without pericardium, and adhere to the walls of the cavity which contains them. In a Python Tigris of seven feet long, the length of each lymphatic heart was six lines, and its diameter four lines and a quarter.\nVenous System.\u2014-The veins of reptiles have very thin walls, and exhibit no fibres in their structure, except in the large trunks of species of considerable size. In the Chelonians and the crocodiles they are furnished internally with a few valves, but these, it would appear, do not exist in the veins of Ophidians, at least they can be injected with facility in any direction.\nAs in other Vertebrata, the veins of reptiles are more numerous than the arteries, and from the frequency of their anastomoses represent rather a net-work than an arborescent arrangement. Their circulation, moreover, not being confined to a determinate course through the lungs, as in Mammalia and birds, the venous system in the Reptilia is never overloaded with blood, as must be the case in the two former classes, when respiration is suspended. And it is probably on this account that their veins appear less capacious, as compared with the arteries, than in those Vertebrata which possess a double circulation. For the same reason they are not dilated into reservoirs as they are in Mammalia and diving birds, or as in fishes, where the blood has but one route through the branchiae.\nThe Chelonians have two posterior ven\u00e6 cav\u00e6 which traverse the liver on each side and receive in their course a multitude of small hepatic veins. Immediately after issuing from the liver, they are each joined by an anterior vena cava of the corresponding side, or by the common trunk of the jugular and subclavian, all of them opening into a kind of reservoir, which communicates with the right auricle of the heart through a slit-like orifice guarded by two valves. The two veins called above posterior venae cav\u00e6 are the umbilical veins of Bojanus, the analogues of\n303\nthe single abdominal or median vein of the Batrachian reptiles, which become confluent by winding towards each other and assuming a transverse direction in the isthmus that unites the lateral lobes of the liver : it is into this single transverse trunk that the two abdominal veins open.\nEach abdominal vein communicates by a pectoral branch with an intercostal vein, and by this intermedium with a cervical branch from the jugular.\nEach abdominal vein has, moreover, an anastomosis posteriorly with the inferior common intercostal ; it is essentially a continuation from the iliac vein, which receives the blood from the femoral, from the iliac circumflex vein, from the ischiadic, from the caudal, from the hypogastric, and from the renal, through the descending trunk of the vena azygos. This latter, after anastomosing in front of the thorax with a cervical branch from the jugular, seems to convey the blood from before backwards, if we may judge from the gradual dilatation of its calibre, as it receives the intercostal veins, the muscular veins of the back, and the branches of the vertebral veins. Its trunk, as it descends towards the kidney, anastomoses with the vein derived from the generative organs, and joins the hypogastric to form the iliac : here, then, we have an arrangement of the venous system which determines the direction of the blood towards the liver, and makes the abdominal vein relatively to the liver what the pulmonary artery is to the lungs. A vein derived from the organs of generation, which, as already stated, anastomoses with the trunk of the vena azygos, likewise runs to the liver, traversing its right lobe like a vena cava, and in the same way receives many small hepatic veins and terminates immediately that it issues from the liver in the great sinus, common to the veins of the body.\nArterial System.\u2014In reptiles there are always two distinct aortas given off\u2019 separately from the heart, and a third artery destined exclusively to the lungs.\nIn the Chelonian order, the two aortas, together with the pulmonary artery, are united together for a little space ; but the former soon separate to take the position and character, one of the right, and the other of the left posterior aortae. The right aorta gives off, shortly after its commencement, a considerable artery, which might be called the anterior aorta, which soon bifurcates ; each division again subdividing into two others, namely, the common carotid, and the subclavian.\nThe subclavian gives off almost the same branches as in the mammalia; namely,\u2014\n1.\tAn artery analogous to the inferior thyroid of Mammalia, which supplies a very vascular cavernous little thyroid body, situated at the bottom of the neck.\n2.\tThe common cervical, which runs forwards under the neck internal to, and beneath the carotid, distributing branches to the muscles and other organs of the throat.","page":303},{"file":"p0304.txt","language":"en","ocr_en":"304\nREPTILIA.\n3.\tA little artery appropriated to the subclavian muscle.\nThe subclavian then bifurcates to form a large ascending branch, and a smaller external branch. From the ascending branch arise \u2014\n4.\tThe superior cervical (vertebral of Bojanus) which supplies the muscles of the superior region of the neck, gives off some spinal branches, and at length becomes confounded with the cervical recurrent.\n5.\tTwo small spinal branches for the vertebr\u00e6 of the neck.\n6.\tAn intercostal branch, which divides to form the two anterior intercostals.\n7.\tThe ascending branch of the subclavian then turns downwards and backwards to form the analogue of the internal mammary, which runs along the external margin of the carapax, receives in succession the intercostal arteries, and ultimately becomes continuous with the epigastric.\n8.\tThe external branch, which is the continuation of the subclavian, gives off several\narteries to the muscles of the shoulder, and to the great pectoral muscle, and then terminates by becoming the axillary artery, which, after giving off twigs to the muscles of the shoulder, becomes in turn the brachial artery. This latter immediately gives off three branches analogous to the circumflex, and to the profunda humeri. It then runs down, remarkably diminished in size, to the bend of the elbow, where it divides into two feeble trunks, the radial and the ulnar, the small size of which is proportionate to the small dimensions of the muscles and other parts of the fore-arm and hand : upon the palmar surface of the latter the ulnar artery forms an arch, as does the radial on its dorsal surface, and from these arches collateral branches are given off in the usual manner to supply the corresponding margins of the fingers.\nArteries of the Neck and Head.\u2014The common carotid runs forward upon the side of the neck, hidden by the muscles connected with the os-hyoides, and in its course sends\nFig. 220.\nViscera of the Female Tortoise (Emys Europceus).\nA', ventricle of the heart ; A, common trunk of the arterial system ; B', right auricle ; B , left auricle ; B trunk of the right aorta ; c, common trunk of the pulmonary arteries ; d, trunk of the left aorta ; e, trachea ; E'E\", carotid arteries; ii, right and left lobes of the liver; k, the stomach; k', commencement of the intestinal canal ; m m, terminations of the right and left oviducts ; n, ovarium ; x t, oesophagus ; u, urinary bladder ; v' v\", right and left supernumerary bladders ; x, external opening of the cloaca ; v, the rectum ; z the lungs ; c, e, g, h, i, truncated vessels arising from the aorta.","page":304},{"file":"p0305.txt","language":"en","ocr_en":"REPTILIA.\n305\nbranches to the oesophagus and neighbouring muscles, until it reaches the head, to which it is distributed without previously dividing into two principal branches, representing the two carotids of mammalia.\nThis difference doubtless depends upon the small size of the encephalon in these reptiles, and it may be remarked that the comparative smallness of the internal carotid, which is here only a subordinate branch of the external Carotid, is not compensated by the size of the vertebral artery, which in the Chelonians does not exist. This last circumstance will not be surprising when it is remembered, that in birds the vertebral artery only supplies the muscles of the neck, the cervical vertebrae, and the spinal chord ; furnishing in the cranium only a single small branch, which is entirely expended upon the medulla oblongata.\nAs in birds, the internal carotid of the Chelonians supplies all the parts of the encephalon.\nThere is a posterior communicating branch, which forms, in conjunction with its fellow, a basilar artery ; which, as it is prolonged backwards beneath the spinal chord, forms an inferior median spinal artery. This last azygos artery gives off near its origin a recurrent branch, which is the superior lateral spinal.\nThe external carotid, which is the principal carotid trunk, resembles in its distribution very closely the external carotid of mammalia ; it may, however, be remarked, that after giving off the lingual branch this artery penetrates into the temporal fossa through the external carotid canal, and that it there divides into two principal branches, one anterior, the other posterior ; the former is appropriated exclusively to the head, and supplies the place both of the internal maxillary and of the temporal of mammalia.\nThe posterior branch of the carotid represents an occipital artery, of which the cervical branch is very greatly developed, so tha^ this occipital seems to be transformed into a recurrent cervical artery, which runs backwards over all the dorsal region of the neck, giving branches to the muscles, to the vertebrae, and to the medulla spinalis, and ultimately anastomoses with the superior ascending cervical artery, derived from the subclavian. The quantity of blood which is thus furnished to the spinal chord of the neck by the recurrent and ascending cervical arteries is very remarkable.\nBranches of the right posterior Aorta.\u2014The two posterior aort\u00e6, in the first instance, run upwards and outwards towards their respective sides, and then turning backwards approach each other so as ultimately to unite nearly opposite the fifth dorsal vertebra by a communicating branch which the left aorta furnishes to the right. Before, however, receiving this artery, the right aorta gives off several branches corresponding with the anterior intercostals.\nAfter receiving the communicating artery, VOL. IV.\nthe right aorta runs backwards beneath the vertebral column as far as the pelvis, giving off in its course the following branches ; \u2014 1st, five arteries on each side analogous to the intercostals ; 2d, the spermatic; 3d, several renal branches to the kidneys on each side ; 4th, several small lumbar branches ; 5th, a small artery analogous to the posterior mesenteric, which is distributed to the cloaca; ultimately, the right posterior aorta terminates by four branches, namely, 1st, the left external iliac ; 2d, the left internal iliac ; and 3d, the common iliac of the right side. Between the two latter trunks arises the caudal artery analogous to the middle sacral. In the green turtle (Chelonia Mydas) the six last intercostals are given off immediately from the right aorta : but in the Emys europea their origin is very different, the five last intercostals being derived from a common anterior intercostal, which arises from the ascending branch of the subclavian. This vessel runs along the spine from before backwards, as is the case in many birds, and ultimately terminates by uniting with a posterior common intercostal: this latter is a branch derived from the iliac artery.\nThe divisions of the internal arteries resemble very closely what is found in mammalia. These vessels first separate into two branches, one of which gives off vessels to the bladder and to the cloaca ; the other plunges into the pelvis, and apparently represents the ischiadic and posterior iliac arteries : the external iliac runs forward along the edge of the pelvis, giving off the analogue of the epigastric, from which arises the anterior iliac. Leaving the pelvis, the external iliac takes the name of crural, and after giving off the circumflex arteries, and the profunda femoris, continues its course, in all respects comparable in the remainder of its distribution to what is found in mammalia and birds.\nThe left {Visceral) Aorta. \u2014 The left aorta furnishes large arteries to the principal viscera of the abdomen, to which it is almost entirely distributed. As soon as it has passed the cardia it divides into three branches ; of these the first, which is the smallest, furnishes a twig to the oesophagus, and is then distributed to the stomach, representing the coronary artery of mammalia.\nThe second, which is almost as large as the trunk from which it arises, supplies the intestines, the spleen, the pancreas, and the liver.\nThe third branch, intermediate in size between the two others, is the communicating artery, given off to join the right aorta, and from which no branches are furnished.\nIn the Saurian reptiles the distribution of the arterial trunks differs but little from that above described.\nIn Lizards the two aort\u00e6 advance forwards out of the thorax ; that of the right side after dividing into three branches, that of the left without any such division. The left aorta winds backward upon the side of the neck, and afterwards runs along the vertebral\nx","page":305},{"file":"p0306.txt","language":"en","ocr_en":"306\nREPTILIA.\ncolumn, receiving at the point where it begins to take this direction from before backwards the left branch of the right aorta, which forms a loop in front of it. From the convexity of this loop arises the left carotid. The two other branches of the right aorta wind backwards, and join together in a similar manner upon the right side of the neck, forming two loops placed one in front of the other. The right carotid arises from the convexity of the loop. The subclavians are given off from each aorta a little before their union, except in crocodiles and the iguana, where they are both derived from the right aorta. The common trunk formed by the union of the two aort\u00e6, which takes place just beyond the apex of the heart, gives off in succession numerous pairs of intercostal arteries. It sends, moreover, shortly after its commencement, an artery to the oesophagus, and subsequently a small branch to the liver; further backwards it gives off an artery which soon divides into two branches : of these the anterior supplies the stomach, the spleen, the pancreas, and the duodenum ; the posterior, which represents the anterior mesenteric, is appropriated to the intestinal canal. The aortic trunk then gives off in succession the lumbar, the spermatic, the posterior-mesenteric, which supplies the rectum, and the renal, which are given off thus late because the kidneys are situated very far back in the abdominal cavity : lastly, it gives origin to the iliacs and the middle sacral arteries. The last-mentioned vessel may fairly be regarded as a continuation of the aortic trunk, from which the iliacs seem to be mere branches ; a circumstance which is owing to the excessive proportions of the tail when compared with the extremities.\nIn the Ophidian reptiles, the absence of limbs, the existence commonly of a single lung, and the extremely slender and elongated form of the body, concur to render the distribution of the arterial trunks very simple throughout this order. These trunks, as in the Chelonians and Saurians, are three in number. Their first divisions, instead of being double and symmetrical, are reduced to single trunks. This is the case, for example, with the pulmonary artery in those serpents that possess but one lung, and also with the common carotid, and the vertebral in the entire order.\nIt is from the convexity of the right aorta, and very near its origin, that the above branches, destined to supply blood to the head and neck, are derived.\nThe right aorta then winds backwards, passes above the oesophagus, and then running obliquely inwards and backwards, it joins the left aorta at a little distance beyond the apex of the heart.\nThe right aorta gives off, a little after its origin, a small artery that supplies a small round glandular-looking mass situated in front of the base of the heart, and subsequently to another similar body of elongated form, situated beneath the jugular vein. It then gives\noff the common carotid, which is single in all the Ophidia. A third artery is given off a little further on, which is the common trunk of the vertebral and anterior intercostals. No other important artery is given off' by the right aorta, and when it joins the left aorta its diameter is very small, so that the greater portion of the blood that this vessel receives from the heart is supplied to the organs which are situated in front of that viscus : it might therefore be properly named the carotid artery.\nThe carotid artery runs obliquely towards the left side, and advances forward, closely connected to the left jugular vein, between the trachea and the oesophagus, and at length is situated beneath the latter. It gives off a great number of small branches to these parts, and near the head divides into several small arteries, which represent both the external and internal carotids.\nWhen the right aorta approaches the vertebral column, it gives off, as stated above, a considerable branch, which supplies th\u00e9 place both of the vertebral arteries and the anterior common intercostals. This artery advances beneath the vertebral column, giving off branches on both sides, opposite each intercostal space, both to the muscles and to the vertebrae of the region which it traverses, and only enters the vertebral column close to the head. This vertebral and intercostal artery likewise gives off recurrent branches, which furnish intercostal vessels behind its point of origin.\nThe left aorta runs upwards, backwards, and to the left side : passes beneath the oesophagus, and afterwards beneath the lung until it reaches beyond the apex of the heart, where it receives the right aorta, and continues its course backwards. It continually gives off branches corresponding to the intercostals and the visceral arteries : those which furnish the stomach, the liver, and the pulmonary sac or sacs, are given off successively from the aorta in its course backwards, so that there is nothing like caeliac axis. Nearly opposite the pylorus it gives off the anterior mesenteric, which runs parallel to the intestine for half its length, to which it constantly furnishes branches. Further backwards the intestinal canal receives in succession three other small branches from the aorta, which gives off as it runs backwards arterial branches to the kidneys, ovaries, and other viscera. Arrived at the termination of the abdomen, it passes on beneath the vertebrae of the tail, in which it becomes gradually expended.\nOrgans of Respiration. \u2014 In several species of Lizards the cavity of the fauces is much enlarged by an expansion of the skin in front of the larynx (fig. 216, d.). These laryngeal sacs, as they are called, appear to be receptacles for air rather than food ; for, although not connected with the larynx, they are extraordinarily distended in rage, &c.\nBefore the termination of the trachea, both in the Coluber natri.v and thiringicus, there is a small blind depression, which, as was first re-","page":306},{"file":"p0307.txt","language":"en","ocr_en":"REPT1LIA.\n307\nmarked by Nitzsch, may be considered a rudiment of the left lung. The right, and in this case sole, pulmonary sac is placed immediately below the spine ; it extends posteriorly as far as the region of the kidneys, and in the Coluber natrix is from five to seven inches long, and from one-half to three-quarters of an inch broad. Its parietes are thickest at the point where the rings of the trachea cease, where it is covered externally by a fibrous layer, and lined internally by a fine lattice-like net-workof vessels. More posteriorly the parietes become gradually thinner, and at last are merely membranous, giving to the whole organ still more of the appearance of a swimming bladder. In the slow-worm (Anguis fragilis) there are two lungs, nearly as in the salamander, though the left is still considerably smaller than the right. The respiratory motion here, as in the amphibia, is unassisted by a diaphragm, and is principally effected by the ribs and abdominal muscles.\nIn Saurian reptiles the respiratory organs are generally formed pretty nearly as in tortoises. The larynx is tolerably simple, without vocal ligaments, and in the chameleon is furnished with a small sac-shaped appendage: in most Saurians, e.g. the crocodile, it opens by a longitudinal fissure; but in the chameleon by a transverse one. This opening is always unconnected, being placed far back, and somewhat covered by the posterior edge of the tongue in the crocodile, but in other species lying more forwards. Many of the species belonging to this order have the power of emitting a sound by the voluntary tension of the rima glottidis, as is known to be particularly the case in the Geckos, where the tongue, which can be thrown back like that of the frog, appears to serve as an epiglottis. In the larynx we already find, particularly in the crocodile, a large pointed anterior cartilaginous lamina as a rudiment of the thyroid cartilage. The trachea and bronchi are nearly the same as in tortoises, i. e. composed of almost completely circular cartilaginous rings. In the Gecko the trachea is particularly wide and somewhat flattened. The lungs likewise form double cellular sacs, extending downwards far behind the liver; whilst in the crocodile, on the contrary, they remain above the liver, and, consequently, more in the thorax, resembling very nearly, both in their shape and position, the lungs of birds. In the chameleon, the lungs are furnished inferiorly with peculiar finger-shaped appendages. Respiration is effected by the thoracic ribs and their muscles, without the assistance of a diaphragm.\nThe Circulation of the Blood.\u2014In Tortoises the heart is situated immediately above the liver, and close behind the abdominal scutum : it consists of two auricles and a ventricle, the latter being divided into several communicating cells, and presenting a broad circular depression, having likewise strong muscular parietes, and being connected at its inferior obtuse extremity by means of a tendinous ligament to the pericardium, as is the case\nin many fishes. The auricles are extremely capacious, eit her of them being very nearly equal Fig. 221.\nHeart of the Tortoise. (After Bojanus.')\nThe ventricle opened in front, the left aorta laid open, and a bristle placed in the pulmonary artery.\nin size to the ventricle : they are divided by a septum, which, however, is perforated in the Testudo scorpioides. The right receives the blood of the body by means of the venae cavae, whilst the oxygenized blood from the pulmonary veins enters the left by a fissurelike valvular orifice. The internal arrangement of the ventricle varies somewhat in different instances ; in some, e. g. the Testudo gr\u00e6ca, it is little more than a simple cavity, rendered irregular by the projecting bundles of fibres of its parietes ; in others, on the contrary, e. g., the T. imbricata, these fibres are so very prominent, and appear to divide the cavity so completely into several cells, that Mery was induced to admit the existence of a ventricle for the pulmonary artery and aorta, in addition to a right and left ventricle. Whether the cavity, however, be simple or complicated, the course of the blood through the heart is always such, that the pulmonary blood enters at the left side, is mixed with the blood of the venae cavae rather towards the back part of the heart, and then passes on the right side into the aorta, and anteriorly into the pulmonary arteries.\nThe principal arterial trunks form a circle Fig. 222.\nHeart of the Tortoise. (After Bojanus.)\nThe ventricle laid open in front, the pulmonary artery slit up, a bristle placed behind a columna camea, which forms an imperfect septum.\nround the oesophagus, which we must consider as a repetition of the branchial arteries. The aorta, which in the T. imbricata is furnished with two semilunar valves, arises double from\nx 2","page":307},{"file":"p0308.txt","language":"en","ocr_en":"308\tREPTILiA.\nthe right side of the heart, a branch ascending from the division to form the axillary and carotid arteries ; whilst the two great lateral trunks bend outwards right and left ; the left, after giving off some branches to the intestinal canal and liver, unites on the vertebral column with the right and larger branch, forming with it the descending aorta which supplies the other parts of the body, a vascular circle being thus produced precisely as in the frog. A second circle, as has been proved by the observations of Meckel and Munniks, is formed by the pulmonary artery, which, like the aorta, is furnished with two semilunar valves, and immediately after its origin divides into a right and left branch, each of which enters one of the lungs ; but, at the same time, communicates with the corresponding branch of the aorta by means of an arterial canal (ductus Bo-talli), which, probably, is permanently pervious. As a consequence of these dispositions, but a small part of the blood is exposed to the action of the atmosphere, and the oxidation of the blood would be even less perfect than in fishes, where all the blood passes through the gills ; were it not that in the latter the respiration is merely of water, and that probably in these and other amphibia there is, in addition to the pulmonary respiration, a respiration of an aqueous kind performed by the permanently existing allantois. As to the veins, it is remarkable that here, according to the investigations of Bojanus, the blood of the whole posterior part of the body, the abdominal coverings, posterior extremities, &c. (with the exception of the venous trunk belonging to the kidneys and sexual organs), is carried into the liver by two trunks, in order to circulate partly in this organ, and partly, according to Jacobson, by means of inferior renal veins in the kidneys, previous to arriving at the heart. The venous blood of the body, as well as that of the lungs, is collected into a venous receptacle for each, close to the auricles, which it then enters in the manner already described.\nIn serpents, the heart is situated towards the middle line of the body, in front of the lungs, and above the liver. Here, also, it is furnished with a left pulmonary auricle, and a right systemic one, which is nearly as large again as the former; both open into the simple and fleshy oblong ventricle, from which arises a double aorta, the branches of which meet again on the vertebral column. The pulmonary artery is single in those serpents where the lung is single.\nIn lizards, the structure of the heart offers a great similarity to that of tortoises, consisting of two separate auricles, and a single ventricle, which, however, is generally divided into several cells. In several species, e. g. the crocodile, the heart is attached by a tendinous ligament to the pericardium. The situation of the heart is here again usually immediately above the liver ; though, according to Cuvier, in the iguana, at a considerable distance from it, and quite in the front part of the thorax. Its auricles are proportionately\nsmaller than in tortoises, and separated by a thin septum, which is perforated in the La-certa apoda. The ventricle, the form of which is tolerably similar to those of the human heart, is divided, in the crocodile, into three anastomosing cells, in such a manner that the blood of the ven\u00e6 cav\u00e6 passes from the right auricle into the two inferior cells on the right side, from which the pulmonary artery and left ascending aorta arise ; whilst, on the contrary, the pulmonary venous blood flows from the left auricle into the left superior cell, which is more distinct from the other two, and which gives origin to the right aortal, carotid, and axillary trunks : the latter vessels, consequently, are not only filled by blood that is more oxidised than that of the left aorta, but also contains a smaller proportion of venous blood than the arteries of the tortoise, inasmuch as but little blood penetrates this from the other two cells.\nAccording to Mr. N. M. Hentz, the American alligator (Crocodilus Indus) presents a much more perfect structure of the heart than any other of the reptilia, the two ventricles not having any immediate communication. From his description the following particulars are derived. The vena cava superior follows the course of the right subclavian artery in its passage through the chest, and descends to the pericardium to join the vena cava inferior opposite the right auricle. In its course upwards, the inferior cava runs upon the right side of the spine until it reaches a straight channel in the substance and near the edge of the liver, where it receives four or five ven\u00e6 cav\u00e6 hepatic\u00e6, A vein analogous to the right subclavian enters the upper part of the right auricle at its left side. The auriculo-ven-tricular opening of the right heart is furnished with two valves. The right ventricle opens into two arterial tubes, of which one is the pulmonary artery ; the other, at the left and upper part of the ventricle, is furnished at its base with two semilunar valves, and terminates in the left aorta. There is not any direct communication between the cavities of the two ventricles. The left ventricle, which is rather smaller than the right, and situated behind and somewhat above it, has also two valves at the orifice by which it communicates with the auricle. Like the right ventricle, also, it opens into two arterial tubes, of which the first leads into the left aorta, and is separated from the corresponding orifice of the right ventricle by a cartilaginous septum only. It is important to observe that this septum interrupts the immediate communication between the cavities of the two ventricles (for they communicate intermediately by means of the artery from each opening into the left aorta), and constitutes the most essential variation of the structure of the heart in this, from what is found in other Saurians. This first branch, arising from the left ventricle, is bordered by a valve at its origin that nearly closes its cavity. The second artery from the left heart divides","page":308},{"file":"p0309.txt","language":"en","ocr_en":"llEPTILIA.\t309\nshortly after its origin into three branches, of which one is the right or systemic aorta, the second the right subclavian, and the third the common trunk of the carotid and left subclavian arteries. The left or splanchanic aorta, previous to dividing among the viscera, gives off a large branch which communicates with the right descending or systemic aorta. The three great arteries, viz. the pulmonary, and right and left aorta, are closely connected together immediately after their origin, and dilate into expansions which are collectively larger than the cavities of the heart. In the common state of circulation the blood passes from the right ventricle chiefly into the pulmonary artery, and partly, also, into the branch arising from it, to enter into the left aorta. The blood of the left ventricle, on the other hand, is thrown into the right aorta, right subclavian, and carotid arteries, a small quantity only passing into the left aorta. When the animal is under water, the action of the lungs being interrupted, and the circulation of blood through them suspended, a larger proportion of the contents of the right ventricle must pass into the branch of communication with the left aorta, and it is probable that under such circumstances only does it happen that the blood sent to the various organs is an admixture of arterial and venous blood, as in the Chelonia and other Sauria.\nIn the serpent (Python Tigris, Dauel.) the blood of the general system is collected into a large elongated sinus, formed by the union of the inferior with the right superior cava. The left superior cava winds round the back of the left auricle, receives the coronary veins, and terminates in the lower part of the orifice which leads from the above sinus to the right auricle. This orifice is protected by two elongated semilunar valves. The whole of the inner surface of the auricle, with the exception of these valves and the opposite valve of the foramen ovale, is reticulated with delicate muscular fasciculi. The left auricle receives the blood from the lungs by a single pulmonary vein, and has a similar muscular structure : there is no valve at the termination of the vein in this auricle. The blood enters the posterior or aortic division of the ventricle by two crescentic apertures, which are each provided with a single semilunar valve, extended from either side of the septum of the auricle. The fleshy septum, which- extends from the base of the ventricle to the space between the roots of the pulmonary and systematic arteries is incomplete at its upper and anterior part, and leaves there a free communication between the pulmonary and aortic chambers : these also intercommunicate by several round apertures of different sizes near the apex of the ventricle, which serve to thoroughly blend together the two kinds of blood, before they are expelled, thus mixed, along the three arteries which separately arise from the ventricles. The origins of the pulmonary artery and left aorta are each provided with a pair of semilunar valves*\nThe carotid arteries are given off from the right aorta, which afterwards unites with the left aorta at some distance below the heart. Nervous System. \u2014 The brain of reptiles, in Fig. 223.\nAnatomy of the Brain of Turtle. (After Swan.')\na. 1, corpus striatum and a lesser oblong eminence seen on opening the lateral ventricle ; on the left side the choroid plexus is seen passing through an opening in the septum, to communicate with that of the right side ; part of the striated body has been removed on the right side ; 2, thalamus of the optic nerve ; 3, optic lobe and ventricle continued forward under the thalami, forming a resemblance of the third ventricle, and then backwards into the cerebellum, and to the calamus scriptorius.\nh. 1, cut surface, from which the striated body has been removed ; it is the crus of the brain, and is somewhat connected with the commissure of the optic nerves : the thalamus on this side has been cut off at its connection with the optic tract. 2, Optic lobe, from which more has been removed than in the preceding figure. 3, Cerebellum, from which more has been removed than in a; two longitudinal bands are continued on from the base of the optic lobes, and terminate near the calamus scriptorius, by being implanted into the anterior portion of the oblong medulla : on each side of these, others less distinct may be observed. 4, fourth nerve, the completeness of its structure, occupies a position intermediate between that of birds and fishes ; it resembles the former in the smoothness of its surface and the small size of the optic thalami, and the latter in the length of the olfactory lobes, and their continuity with the anterior extremity of the hemisphere ; its proportionate size relative to the dimensions of the body is, however, far inferior to that of birds, although it still completely fills the cranial cavity.\nThe olfactory lobe of the brain is hollow, and its cavity communicates with the ventricle contained in the cerebral hemisphere. Each hemisphere, as in birds, consists of a central portion, or corpus striatum, the relative size of which varies in different orders, and of a nervous expansion which incloses the ventricle above and on its inner side.\nThe optic thalami are small, and occupy their usual position on each side of the third ventricle. The tubercula quadrigemina are situated as ordinarily above the aqueduct : they are of a rounded form, and, as in birds, contain a ventricular cavity, which is in communication with the third ventricle. The anterior and posterior commissures of the\nx 3","page":309},{"file":"p0310.txt","language":"en","ocr_en":"310\nREPTILIA.\nbrain occupy their usual position, but there is no commissura mollis. The cerebellum is generally extremely small, and in some cases is even reduced to a simple transverse lamella, which does not entirely cover the fourth ventricle, formed as usual by the separation of the posterior columns of the\nFig. 224*.\nc,\tlateral view of the brain of a turtle ; 1, optic tract ; 2, crus cerebri.\nd,\tthe same : a portion of the optic nerve has been removed to show the crus cerebri passing upwards. (After Swan.')\nspinal chord. The inferior surface of the brain is almost smooth, presenting no other elevations than those formed by the union of the optic nerves and by the tuber cinereum. As there are no lateral lobes to the cerebellum, of course no traces of a pons varolii exist. As in birds, a vascular inflation, which seems to represent the fissure of Sylvius, separates each hemisphere into two lobes, into the posterior of which the lateral ventricle penetrates. The pineal and pituitary bodies are met with in all reptiles.\nIn the Chelonian reptiles the cerebral hemispheres contain as usual a ventricle, in which may be perceived a body analogous to the corpus striatum, presenting an arrangement very similar to what is observed in birds, only it is much less voluminous, so as to occupy a small portion comparatively of the interior of the ventricle. The crura cerebri, when they reach the lobes of the hemispheres, do not, as in mammalia and in birds, immediately dilate into large ganglia, but curving upwards and backwards, expand on each side into a tubercle, which is the corpus striatum. The optic thalami are very small, but the pineal gland which lies upon them is of considerable bulk.\nThe bigeminal tubercles are of a rounded form, and instead of being separated from each other by a slight groove, as in the mammalia, a deep fissure is interposed between them which penetrates to the roof of the aqueduct, and contains a fold derived from the pia mater.\nThe cerebellum is nearly hemispherical in its form, consisting of an arched layer of nervous substance of equal thickness throughout, which spreads over a portion of the fourth ventricle. The remainder of that cavity is covered by a vascular plexus, derived from the sides of the medulla oblongata, which forms a sort of valve, and by becoming united to the margin\nof the cerebellum, completes the roof of the fourth ventricle, which is large and prolonged very far back. The anterior columns of the spinal chord form a very distinct projection into the floor of this ventricle, as they advance upwards towards the brain. A similar disposition exists in the crocodiles, and in the Sau-rian reptiles generally ; the principal differences being that the hemispheres are proportionall} larger, and do not separate from each othei so as to display the optic thalami; the olfactory bulbs also are less closely approximated to the cerebral hemispheres, with which they are sometimes connected by the intervention of a narrow pedicle, in which, however, a canal is always to be detected, communicating between the ventricles and the cavity of the bulb. The corpus striatum is comparatively larger than in the Chelonians, occupying a considerable proportion of the base of the Fig. 225.\nBrain and Nerves of Boa Constrictor. (After Swan.)\na, anterior lobe of the brain ; b, optic lobe ; c, cerebellum ; d, Schneiderian membrane of the nose ; 1, olfactory nerve; 2, optic nerve; 3, third or common oculo-muscular nerve cut short ; 4, fourth nerve given to the superior oblique muscle of the eye ; 5, first trunk of the fifth ; 6, second trunk of the fifth ; 7, third trunk of the fifth ; 8, hard portion of the seventh nerve ; 9, auditory nerve ; 10, glossopharyngeal nerve; 11, trunk of the par vagum ; 12, ninth nerve ; 13, ganglion of the sympathetic nerve, as in fig. 22G ; 14, a branch of the sympathetic nerve passing to the palatine nerve, as in fig. 226.","page":310},{"file":"p0311.txt","language":"en","ocr_en":"REPTILIA.\t311\nhemisphere, and projecting considerably into the lateral ventricle. The furrow which separates the bigeminal bodies is not so deep in the Saurians as in the Chelonian order. The cerebellum is very small, being represented by a transverse layer of nervous substance. In the Ophidian reptiles the two hemispheres form together a mass which is broader than it is long ; the olfactory bulb is frequently of very large size, as, for example, in the Python (fig. 225) ; the corpus striatum is much smaller than in the Saurians. In the Python it is divided. The bigeminal tubercles are almost globular in many species, and much smaller than the hemispheres behind which they are situated. In the Python they are remarkable, inasmuch that they are four in number, and closely resemble the corpora quadrigemina of mammalia.\nThe cerebellum of serpents (fig. 225, c.) is exceedingly small and flattened ; it has the shape either of the segment of a circle or of a thin quadrilateral lamina, which partially covers the fourth ventricle.\nIn reptiles, as in birds, the medulla spinalis is permeated by a canal, which is lined internally with grey substance. In the Saurian and Ophidian reptiles this canal extends as far as the first coccygeal, but in the Chelonians it is shorter.\nThe origin of the nerves derived from the encephalon and spinal chord closely resembles what is met with in the higher vertebrata: their general distribution will be best understood by referring to the explanations appended to the annexed figures, copied from Mr. Swan\u2019s elaborate work on the Comparative Anatomy of the Nervous System.\nNerves of Boa Constrictor. (After Swan.)\n1, ganglion of the sympathetic nerve, situated near to, and connected with, the trunk of the par vagum. 2, a branch of the sympathetic nerve passing some way in a canal at the base of the cranium, and forming a small ganglion with a branch of the second trunk of the fifth; it sends filaments to the membrane covering the posterior part of the mouth and palate, one of which communicates again with the second trunk of the fifth\nbefore its termination ; the ganglion then sends another branch forward to form another glanglionic union with a branch of the second trunk of the fifth, and from this a branch is sent to the posterior part of the nose to ramify on the Schneiderian membrane ; other branches are given to the membrane covering the mouth and palate, and one passes forward and communicates again with a branch of the second trunk of the fifth, and is distributed on the membrane covering the anterior part of the mouth\nx 4","page":311},{"file":"p0312.txt","language":"en","ocr_en":"REPTILIA.\n312\nand palate. It is worthy of remark, that the nerves distributed on the membrane of the mouth and nose communicate so many times with branches of the second trunk of the fifth, and their connexion is so much greater than in the turtle; but in this creature, the palate is horny, and not so extensive in proportion to the size of the head. 3, prolongation of the sympathetic connected with the trunk of the par vagum, but not directly with the ganglion of the sympathetic ; it communicates with the ninth nerve, then passes down the spine and communicates with the eleven superior spinal nerves ; it emerges on each side at the place the superior branches of the vertebral artery enter to distribute branches in the intercostal spaces ; it is continued downwards in a very fine plexiform prolongation with the vertebral artery, as far as the origin from the right aorta; it then branches to each side beneath the membrane connecting the viscera with the ribs and spine, and communicates with filaments of the par vagum ; it is afterwards continued downwards, receiving a filament from each spinal nerve ; in its course it is a very fine nerve, and has not any more ganglia than the first, and those communicating with the second trunk of the fifth ; but at different points from which the nerves pass to the viscera, there is an appearance of a delicate plexus : this plexiform structure varies in different parts, and becomes much greater about the beginning of the intestine, where it resembles that corresponding with the semilunar ganglion in the turtle; near the kidney it assumes the form of a nervous membrane or retina, before it is distributed on the urinary and generative organs. Branches pass from the plexuses with the arteries to the different viscera. 4, second trunk of the fifth; after communicating with the sympathetic, and giving filaments to the membrane of the mouth, palate, and nose, it passes out of its canal in the upper jaw, and terminates in branches on the upper lip. 5, third trunk of the fifth ; it gives branches to the muscles of the jaws, the greatest portion of it then passes within a canal in the lower jaw; it sends three branches through the opening at the inferior margin of this part, two of them to communicate with the branches of the par vagum and ninth, distributed on the muscles and parts underneath the jaw ; the other to give filaments to the membrane of the mouth as far as the sheath of the tongue: the trunk is continued onwards through the foramen, near the chin, to divide into branches and terminate on the lower lip. 6, hard portion of the seventh ; it communicates with the ganglion of the sympathetic, and then passes through the digastric muscle, to which it gives a branch; it communicates with the first spinal nerve, and terminates on the costomaxillary muscle, 7, glosso-pharyngeal\nSympathetic System.\u2014The sympathetic system of the tortoise is so feebly developed as to be detected with difficulty, except in the interior of the carapax, where nervous ganglia are distinctly recognisable both in the peritoneal folds and on the bodies of the vertebrae.\nThe ganglia exactly resemble those of birds; they give off two filaments \u2022superiorly and two interiorly : the latter pass beneath the transverse process of the vertebrae, which is here connected with the carapax. From the inner margin of each ganglion a splanchnic nerve is given off, which runs to assist in forming a plexus, ramifications from which accompany each of the arteries given off by the aorta, and likewise assist in forming a pulmonary plexus. The intercostal ganglia may be traced as far as the sides of the first vertebra of the tail.\nBojanus has represented the sympathetic of the European tortoise (Emys europ\u0153a) as\nnerve ; it passes to the ganglion of the sympathetic. 8, trunk of the par vagum ; it communicates with the sympathetic, and then with a branch that appears to be the continuation of the glosso-pharyngeal from the ganglion of the sympathetic; it sends a branch to communicate with the ninth, to pass to the muscles, &c., of the fauces ; and is then continued downwards close to the trachea, in company with each jugular vein ; on the left side it also accompanies the carotid artery, and from this a small vessel also ascends with the right trunk; it sends filaments on the large vessels towards the heart, and others behind each aorta, similar to the recurrent nerves, to be distributed on the trachea and oesophagus ; each trunk, for a short space, accompanies its corresponding pulmonary artery : a little above the liver it passes in front of the superior part of the lungs, and proceeds a short distance, where it is joined by its fellow to form a single nerve; this is continued downwards under a thick membrane on the liver, and appears to give filaments to this viscus, the lungs, and oesophagus : about the termination of the liver it sends a large branch, which has communicated freely with branches of the sympathetic to the left surface of the stomach; this gives filaments to the lowest part of the lungs, and terminates on the stomach. The right division, or the continuation of the nerve itself having communicated several times with the left division and filaments from the plexus of the sympathetic, is continued a short way on the membrane connecting the viscera, it passes on the right surface of the stomach, distributing branches to this viscus, and terminates on the beginning of the intestine, reaching as far as the pancreas. 9, a nerve from the ganglion of the sympathetic ; it appears to be the continuation of the glosso-pharyngeal after its junction with the ganglion, it communicates with the ninth after its connection with a branch of the trunk of the par vagum, and terminates on the glottis and muscles attached to the anterior point of the jaw for drawing forward the trachea. 10, ninth nerve ; it receives a branch from the trunk of the par vagum, and from the hard portion of the seventh ; after this has communicated with the first cervical nerves, it gives off several branches to the muscles of the tongue and throat, and one that reaches to the end of the tongue, and one to communicate with branches of the third trunk of the fifth, issuing out of the inferior part of the lower jaw. The glosso-pharyngeal, the trunk of the par vagum, and the ninth, are so connected together that it is difficult to determine precisely to which nerve each branch belongs; they have been with great care apportioned to their respective nerves in this description.\naccompanying the carotid artery into the cranium, and uniting with the vidian and the facial nerves. On issuing from the cranium, he describes it as being closely connected with the vagus and with the glosso-pharyngeal nerves, so that it is difficult to say whether a superior cervical ganglion exists or not; and as the cervical vertebra are here devoid of the vertebral canal, the nerve is equally inseparably connected with the vagus throughout the whole length of the neck. Below the sixth cervical vertebra the sympathetic nerve separates itself from the sheath of the vagus, and becomes connected with a middle cervical ganglion, whence issue filaments that are distributed to the aorta, the cardiac plexus, and the caeliac plexus. Between the seventh and eighth cervical vertebrae is situated the inferior cervical ganglion, which seems to be merely an elongated swelling of the nerve;","page":312},{"file":"p0313.txt","language":"en","ocr_en":"REPTILIA.\nsubsequently two dorsal ganglia occur, and further down, towards the middle of the back, there occurs a third and last ganglion, which furnishes the splanchnic nerve : the remainder of the sympathetic is made up of one or two cords, which, in the sacral region, give off a great number of branches, the divisions of which form the renal, hypogastric, and sacral plexuses.\nAccording to Mr. Swan, in the turtle (Testudo Mydas), the sympathetic is free and distinct throughout the whole length of the neck, but it gives off filaments of intercommunication to the nervus vagus. One of its branches passes along with the division of the carotid artery into a canal in the base of the cranium, gives off a filament to the facial, and communicates with the second division of the fifth pair.\nOrgan of Hearing. \u2014In all reptiles the organ of hearing is constructed to appreciate sounds communicated through the medium of the atmosphere, and consequently differs from that of fishes in several important particulars, amongst the most obvious of which is the addition of a membrana tympani and tympanic cavity, wherein is lodged an ossiculum auditus, the office of which is to convey the vibrations of the tympanic membrane to the labyrinth contained within the skull.\nIn all reptiles the internal ear consists of the same parts as that of fishes, only they are comparatively of smaller size and more compact in their arrangement. In crocodiles and lizards, the internal ear consists of three semicircular canals, which exhibit the usual arrangement, each canal forming a considerable portion of a circle, and presenting internally a membranous ampulla before opening into the vestibule.\nTowards the interior of the skull, there is an organ appended to the vestibule, which is evidently analogous to the sac met with in the ear of fishes. The walls of this sac are membranous, and copiously supplied with bloodvessels. It is found to contain in its interior three otolithes ; but these are very small, and even of softer texture than those of the chondropteriginous fishes.\nBesides the above parts, the internal ear of reptiles presents for the first time an additional part, which is undoubtedly a rudimentary cochlea. This is an appendage to the vestibule, of a conical shape, and slightly bent towards its extremity ; it lies inferior to the vestibule, its apex being directed towards the mesial line of the cranium. On opening this organ, it is found to be divided internally into two compartments by a double cartilaginous septum : the two compartments communicate w ith each other towards the apex of the cone, whilst at their opposite extremities one of them is found to open into the vestibule, whilst the other terminates at a small orifice closed by membrane, which communicates w'ith the tympanic cavity. This organ, it will be perceived, is precisely comparable to the rudimentary cochlea met with in the ear of birds, the two canals representing respectively\n313\nthe sc ala vestibuli and the scala tympani of the human ear. In Crocodiles this cochlea is of considerable size, and may be easily exhibited in very young individuals ; it is more difficult to find in the Chameleon and in Lizards, whilst in Serpents it is reduced to a very rudimentary condition. In Tortoises, that part of the ear which seems to represent the rudimentary cochlea resembles exactly that part of the ear called by Cuvier the sac, both in its shape, and from the circumstance of its containing otolithes, and he is disposed to consider this sac as truly analogous to the cochlea of the human ear; whilst that portion of it which he calls the sinus, he considers as representing the vestibule.\nIn all reptiles the membranous labyrinth is enclosed in an osseous sheath, which embraces it more or less closely in different genera ; in the Saurians the bony labyrinth is complete, but in Tortoises that portion which separates the vestibule from the cranial cavity is not ossified, but remains partially membranous.\nThe tympanic cavity, which in reptiles is for the first time interposed between the ves tibule and the exterior of the body, varies in its arrangement in different genera. In the Crocodiles this cavity might be divided into two portions, one external, which is very wide, and is closed externally by the membrana tympani and the skin ; and an internal portion, which is separated from the former by a constriction. It is in this latter compartment that the two fenestr\u00e6 are situated ; and it contains, moreover, some cavities which are analogous to the mastoid cells, but of much larger size than in mammiferous animals. The position of the tympanum in this reptile is near the upper part of the cranium.\nThe tympanic cavity of the Chelonian reptiles is situated much more laterally than in the crocodile, and the constriction which separates the external from the internal portion is less remarkable. The internal compartment of the tympanum is here prolonged backwards into a wide rounded cell. At the bottom of this cavity, just opposite the membrana tympani, there is a narrow canal leading to the fenestra ovalis, in which the ossiculum auditus is lodged. The Eustachian tube is a canal of moderate length, which runs downwards and slightly backwards to communicate with the palate just behind and internal to the articulation of the lower jaw.\nIn the generality of Saurian reptiles, the walls of the tympanic cavity are membranous posteriorly and inferiorly : the Eustachian canal is very short, and opens into the palate. In many genera the tympanic bone is much enlarged superiorly, so that the cavity of the tympanum is made more extensive : this arrangement is most conspicuously seen in the genus Draco.\nIn Serpents there cannot, strictly speaking, be said to be any tympanic cavity, the handle of the auditory ossicle being imbedded amongst the flesh, so that its extremity only touches the skin close behind the articulation of the lower jaw.","page":313},{"file":"p0314.txt","language":"en","ocr_en":"REPTILIA.\n3U\nIn all reptiles there is but one ossiculum auditus (the columnella), which is generally of a trumpet shape. Its external extremity is in the Saurians connected to the membrana tym-pani by means of a cartilaginous process ; but in tortoises it is implanted directly into the membrana tympani, which has a cartilaginous texture. The inner extremity of the auditory ossicle enlarges into an oval or triangular disc (Patina), which is applied to the fenestra rotunda, in the same way as the disc of the stapes is in the ears of mammalia.\nIt does not appear that there are any muscles implanted into the auditory ossicle of the reptilia. In most reptiles that possess a membrana tympani, it is situated on a level with the general integument. In the crocodile, however, something like an external meatus exists.\nOrgan of Vision. \u2014 In all the reptilia the eye resembles, in its general structure, that of birds and quadrupeds : there are, however, certain modifications rendered necessary by th\u00e8 habits of these animals, many of which are semi-aquatic in their habits, which it will be important to notice.\nThe sclerotic coat of the eye is very similar\nFig. 227.\na, lachrymal gland of a tortoise ; b, eye-ball of a tortoise ; c, circle of osseous sclerotic plates. (After Bojanus.)\nin its composition to the sclerotic of a bird ; and in like manner, in many reptiles, contains in its anterior portion a circle of horny plates, which are enclosed between its laminae without being continuous with the substance of the membrane, from which they are consequently easily detached. These plates are generally ten or twelve in number, and are constantly met with in tortoises, and also in the crocodiles, chameleons, and many other lizards. In many genera the sclerotic is divided into two layers, the external being fibrous and of equal thickness throughout its whole extent ; whilst the internal layer is of a cartilaginous texture, and is thicker at the posterior part of the eye than it is in front. This layer in the vicinity of the entrance of the optic nerve is perforated by numerous foramina for the passage of bloodvessels.\nThe structure of the cornea presents nothing remarkable, but its convexity varies considerably in different genera.\nThe choroid coat of the eye exhibits the usual structure. In lizards and serpents the ciliary processes are scarcely distinguishable ; and in the Chelonians their existence would be doubtful were it not for the elegant impression left by them upon the vitreous humour. In the crocodile, however, these processes are well developed, and very beautiful.\nThe iris, to some extent, resembles that of fishes, having frequently the same metallic splendour. The shape of the pupil varies: in the crocodile it is a vertical slit, like that of the cat ; in the tortoise it is round, as likewise in the chameleon and the generality of lizards.\nThe optic nerve enters the eye externally\nFig. 228.\nSection of the Eye-ball of a Tortoise. (After Bojanus.)\nto the axis of vision, piercing the membranes of the eye, as in the mammif'erous classes : arrived in the interior of the organ, it forms a small tubercle, from the circumference of which the retina takes its origin.\nIn many reptiles the falciform ligament usually met with in the eyes of fishes is still perceptible ; and in some genera, such as the lizards, the iguana, and the monitor, there is a cylindrical membranous process covered with black pigment, which passes from the insertion of the optic nerve to the capsule of the crystalline lens, and which is evidently the representative of the pecten common to the eyes of birds.\nThe aqueous and vitreous humours offer no peculiarity worthy of notice ; and the same may be said of the crystalline lens, which, however, differs in the convexity of its facets in different genera.\nAppendages to the Eye. \u2014 The eye of reptiles is moved by the six ordinary muscles, which are disposed as in fishes ; but besides these, there are four smaller muscles representing the suspensory or choroid muscle of quadrupeds: these latter closely embrace the optic nerve, and spread over the convex portion of the sclerotic.\nIn the Chelonian and Saurian reptiles the upper and lower eyelids are completely developed, and accurately close the conjunctival cavity. There is also a well-developed nictitating membrane, or third eyelid, which is situated vertically at the inner canthus of the eye, and has a horizontal motion over the cornea. In the crocodiles the nictitating membrane is moved by a special muscular apparatus ; its muscle, the nictitator, arises from the inner and upper part of the eye-ball, and running outwards and downwards winds round the optic nerve, and the suspensory muscles of the eye (which latter serve to protect the nerve from the pressure of the nictitator muscle), and is inserted into the inferior angle of the nictitating membrane, which it thus draws","page":314},{"file":"p0315.txt","language":"en","ocr_en":"REPTILIA.\n315\noutwards over the eye-ball, while at the same time it rotates the eye-ball inwards beneath the membrane, the muscle being attached to move-\nFig. 229.\nAn external View of the Eye, Eyelids, Muscles, 8\u00e7c. of a Crocodile. (After John Hunter.')\na, the external surface of the upper eyelid ; h, the external surface of the under eyelid ; c, points to the edge of both eyelids ; d, the inner angle or canthus of both eyelids ; e e, the internal surface of the eyelids covered by the tunica conjunctiva ; f, point, to the two puncta lachrymalia on the inside of the under eyelid; g, the external surface of the third eyelid, or membrana nictitans ; h, the loose or free edge of the same ; k, the opening of the duct of the lachrymal gland (glandula Harderii) upon the inner surface of the nictitating membrane ; this surface has been raised from the cornea, to which it naturally lies contiguous ; l, the muscle which expands the membrana nictitans, and draws it over the ball of the eye. This is the only muscle which is subservient to the movements of the nictitating membrane ; it is analogous to the pyramidalis of birds, the quadratus muscles and its sheath being wanting in reptiles ; m, the levator muscle of the upper eyelid ; n, the portion of the above muscle lost in the tunica conjunctiva; o, the depressor muscle of the under eyelid ; p, the rectus superior, or attollens oculi ; q, the rectus inferior, or deprimens oculi ; r, the rectus extemus, or abducens oculi ; s, the obliquus inferior : only a small portion of,it is here seen ; t, the cornea ; u u, the globe of the eye behind the cornea ; v, the optic nerve; x, insertion of the choroid muscle, which consists of four distinct portions surrounding the optic nerve.\nable points at both extremities. The quadratus muscle, which in birds forms a loop for the passage of the tendon of the nictitator, does not exist in the reptilia. There is a gland especially appropriated to facilitate the movements of the nictitating membrane by its secretion, which escapes through a duct opening upon its inner surface. This gland is analogous to the Harderian gland of quadrupeds.\nThe lachrymal gland is generally of large size, and consists of a thick broad conglomerate mass, which surrounds the upper and outer portion of the eye-ball: its duct is short and wide, and terminates just above the external canthus of the eye.\nIn the annexed drawing, copied from one in the Hunterian collection, the eye, eyelids, and muscles of the eye-ball of the crocodile are represented.\nFig. 230.\nEye-hall of Tortoise : shewing the lachrymal Gland in situ. (After Bojanus.)\nThe common Lizards have, for eyelids, a kind of circular veil, extended before the\nFig. 231.\nEyelids of Tortoise. (After Bojanus.)\norbit, and perforated by a horizontal fissure, which is capable of being closed by a sphincter muscle, and opened by a levator and depressor : its inferior part has a smooth round cartilaginous disc, as in birds. There is, besides, a small internal eyelid, but it has no proper muscle ; it is entirely wanting in the chameleon, in which animal, also, the slit of the eyelids is so small that the pupil can scarcely be observed through it. The Gecko has no moveable eyelid : its eye is protected by a slight margin of the skin, as in serpents. A similar disposition appears in the Scink.\nThe horizontal eyelids of the reptilia close exactly ; they are generally slightly enlarged at their margins, but are never furnished with cili\u00e6.\nThe eye of Serpents is protected by an eyelid of a very remarkable character ; for that it is an eyelid, and not, as is very generally supposed, the cornea, its anatomical relations abundantly prove. It consists of a transparent membranous expansion, which is immoveably fixed in a kind of frame formed for its reception by a circle of scales, usually seven or eight in number, disposed around the margin of the orbit. This eyelid is formed of three superposed layers* : viz., 1st, An epidermic layer, which is elastic and pretty thick where it covers the middle of the eye, but towards the circumference of the eyelid it becomes thinner, and is manifestly continuous with the epidermis that invests the scales in the vicinity of the orbit. This corneous lamella by its solidity is well adapted to defend the eye, and it is this which becomes detached and cast off with the slough of the snake when it moults its skin. 2dly. Beneath this epidermic layer is situated a second\n* Vide Cloquet (Jules), M\u00e9moire sur l\u2019Existence et la Disposition des Voies lacrymaux dans les Serpens. 4to, Paris, 1821.","page":315},{"file":"p0316.txt","language":"en","ocr_en":"3IG\nREPTILIA.\nmembrane, which is the middle tunic of the eyelid. This is very delicate and soft, and perfectly transparent in the centre, but to-\nFig. 232.\nDiagram of the Conjunctiva of a Serpent. (After Cloquet.')\na, eye-ball ; h, optic nerve ; c, eyelid ; d, skin ; e e, f conjunctiva.\nwards its circumference it encloses some opaque whitish fibres, supposed by Cloquet to be muscular. This layer, at the margin of the orbit, is manifestly continuous with the dermis: internally it is lined by the third layer, which is mucous, being in fact the membrana conjunctiva, which is reflected on to it from the surface of the eye-ball.\nAll around the circumference of the eyelid there is a whitish, granular, transparent substance, the nature of which is apparently glandular.\nThe lachrymal apparatus in serpents consists of a lachrymal gland ; of a mucous sac formed by the conjunctiva, into which the secretion of the lachrymal gland is poured ; of an excretory duct, or lachrymal canal ; and moreover of a large and tortuous cavity, which receives the tears and transmits them into the mouth.\nThe lachrymal gland is proportionally of very great size, and is situated behind the eye and the post-orbital ligament. By its anterior surface, which is concave, it adheres to the conjunctiva by means of its numerous small excretory ducts. This gland is enclosed in a very delicate cellular capsule. It is made up of rounded whitish granules united together by numerous vessels and nerves.\nThe conjunctiva lines not only the internal surface of the eyelid, but also a large portion of the cavity of the orbit, from which it is reflected on to the front of the eye-ball, thus forming a complete sac without any opening externally (fig. 232, f). On the anterior part of the floor of this sac there is a single pore, large enough to admit a hog\u2019s bristle. This is the punctum lachrymale, which is single like the eyelid, behind and beneath which it is situated : the punctum leads into a very delicate membranous tube, which constitutes the lachrymal canal. This latter passes downwards and forwards, enters an infundibular channel in the lachrymal bone, and passing through this, arrives at the external wall of the nasal fossa, with which, however, it does not communicate, but passes on to open into a wide tortuous cavity, named by Cloquet the intermaxillary sac.\nUrinary Apparatus. \u2014 The arrangement of the urinary apparatus is very similar throughout all the oviparous vertebrata. The kidneys are invariably situated very far back in the abdominal cavity, where they are suspended beneath the spine. They are distinguished from the same glands in mammalia by the circumstance of their presenting no division into cortical and medullary portions, and by the total absence internal^ of any pelvis or infundibulum, their whole substance seeming to be made up of convoluted c\u00e6cal tubes.\nThey vary slightly in the different orders in their form and relative size, the principal differences worthy of notice. In Chelonian order they are short, oval masses, of a somewhat prismatic shape, or else, as in the turtle (Testudo caretta), they are flat and triangular. Examined superficially, they have the appearance of being divided into numerous lobules, so that their surface has a convoluted appearance, somewhat like that of the human brain ; but towards the centre of the organ, this lobulated structure is not distinguishable. They are situated very far back, occupying a very considerable space in the pelvic region.\nIn the Saurians likewise, the kidneys seem externally to be more or less divided into lobules; they are generally almost entirely contained in the cavity of the pelvis, where they are placed side by side beneath the arch of the sacrum, extending backwards even to beneath the tail, so that they are situated immediately above the cloaca. Their shape is also more elongated than in the preceding order.\nIn the Ophidian reptiles the kidneys are much elongated, so as to adapt them to the slender shape of the body of the animals ; and they are composed of distinct lobes placed one before the other, and connected loosely together, so as not to interfere with the flexibility of the body. For the same reason the two kidneys are not placed upon the same level, but the right is situated considerably farther forward than the left ; they are, moreover, only loosely connected with the spine by broad processes of peritoneum, in which they are enveloped ; an arrangement which leaves the movements of the spinal column perfectly free.\nThe kidneys of the reptilia seem to be entirely made up of convoluted uriniferous tubes, which as they issue from the different lobes unite successively to form a common duct, which runs along the external border of the organ, and constitutes the ureter. The common trunks of these urinary canals occupy the fissures between the different lobes of the kidneys, in each of which they divide very regularly as they diverge, so that their ramifications have a pyriform appearance (u7%. 233, tt).\nIn the embryo and in very young reptiles the kidneys seem to be made up of pyriform vesicles which are arranged transversely, their pedicles terminating at right angles in the ureter ; or else they are made of simple tubes disposed in a similar manner. The","page":316},{"file":"p0317.txt","language":"en","ocr_en":"REPTILIA.\n317\narteries of the kidneys penetrate these organs by their inner margin, whilst the trunks of the emulgent veins occupy the opposite border. These latter are two in number, one\nFig. 233.\nGenerative and Urinary Apparatus of the Rattlesnake ( Crotalus JDurissus').\na, the intestines cut off just below the pylorus ; h, the gall-bladder: c, the biliary duct, that passes through the middle of the spleen,\u2014 or, as called by Carus, the pancreas,\u2014 and enters the large gut ; d, the spleen, or pancreas; e, the intestines, which were very large and winding, but short; ff the rectum ; h h, the testes ; i i i, the vasa deferentia ; k k, the penis on each side, which first at the root are conjoined, and are thick beset with bristles; l, the muscles that serve for drawing in the penis; m, the scent-bags ; ttt, secretory vessels.\nof which unites with its fellow from the opposite kidney to form the commencement of the posterior cava. The other communicates with the veins returning the blood from the posterior extremities and the tail ; it is this latter vessel which Mr. Jacobson regards as forming the portal vein of the kidneys.*\nThe ureters are longer or shorter in proportion as the kidneys are more or less advanced forwards ; they terminate in the cavity of the cloaca, their openings being in the\n* Vide the article Ren.\nvicinity of the allantoid sac, if that viscus is present. The allantoid sac, generally called by authors the urinary bladder, in no case immediately receives the terminations of the ureters, and its presence is by no means constant. In the Chelonian order it is very large, and is divided at its fundus into two portions ; but its walls are very thin and membranous. It is likewise met with in the following genera of Saurians ; namely, the Iguana, the Tupinambis, Chameleon, Draco, and Stellio ; while it is wanting in the Crocodiles, Lizards, Agame, Gecko, and other genera of the same order : it is likewise deficient in all the Ophidians. The fluid contained in this reservoir, when it is present, yields, upon analysis, but very slight traces of urea or uric acid ; so that its claims to be considered as being the real urinary secretion have been doubted, although its urinary character has been admitted by Vauquelin and others.\nIn the Chelonian reptiles the urine is a limpid or slightly-coloured fluid ; but in the generality of Saurian reptiles (with the exception of the crocodiles), and likewise in all serpents, it is a white soft substance, which hardens on exposure to the atmosphere into a mass resembling chalk. This solid urine is found on analysis to consist almost entirely of uric acid ; it contains besides a very small proportion of ammonia of potash and soda in combination with uric acid, and also traces of phosphate of lime and animal matter.\nThe Emydes among the Chelonian reptiles are furnished with two very remarkable accessory bladders, the size of which exceeds that of the urinary bladder itself ; but what is very remarkable, these are met with neither in the land-tortoises nor in the turtles. They are likewise deficient in the genus Trionyx. These accessory bladders are of an oval or cylindrical shape, and are so situated, that they can be compressed by the abdominal muscles. Their walls are extremely delicate, and seem to consist only of an external peritoneal coat lined with mucous membrane ; no muscular fibres being recognisable in their structure. They are extremely vascular ; the blood-vessels forming a rich net-work over their outer surface. Their use is not yet accurately determined, but it seems probable that the tortoises which exhibit this structure are able to fill the accessory bladders with water and perhaps with air, so as to diminish the specific gravity of their bodies. Should this be the case, it will explain why these organs are deficient in the land tortoises, which never enter the water, and also in turtles, which, from their organisation, are well able to swim without such auxiliaries, more especially as the specific gravity of seawater is much greater than that of fresh. In the Trionyx, also, the extremities form such powerful oars, that additional means of swimming are not required.\nMale Organs of Generation. \u2014 In all the three orders of reptiles the general arrangement of the generative system of the males is similar","page":317},{"file":"p0318.txt","language":"en","ocr_en":"318\nREPTILIA.\nand conforms very closely to what exists in the class of birds. The testicles are invariably two in number, and situated in the abdominal cavity on each side of the spine, their position being more or less advanced forwards according to circumstances : they are, however, constantly in juxtaposition with the kidneys, beneath or in front of which they are always placed. In the Chelonians they are always found to be connected with the inferior surface of the renal glands, which are here situated at the bottom of the abdominal cavity. In the Saurians they are placed in front of the kidneys on each side of the spinal column. They occupy a similar position in the Ophidian order, except that the right testis is in all serpents advanced further forwards than the left.\nThe intimate structure of the testis is essentially similar in all the reptilia. Each testis\nFig. 234.\nMale Organs of Generation, and Kidney of the Tortoise. (After Bojanus.')\nm, m\", the urinary bladder laid open ; o, the left kidney ; p, the renal capsule ; 8, uriniferous tubes derived from the kidney, which by their union form the ureter ; n, ureter ; f, common termination of the ureter and of the vas deferens at the neck of the bladder, close to the commencement of the urethral groove; m, ditto of the opposite side; y, the testes; c, the vas deferens; e, the bulb of the penis ; G, commencement of the urethral groove, just anterior to the openings common to the ureters and the vasa deferentia.\nis found to consist of large fascicles of seminiferous tubes, which are connected together by a delicate cellular tissue, and are, generally, easily separable. The seminal ducts derived from all these fascicles unite to form the commencement of the vas deferens, which is very tortuous and folded upon itself, so as to form an epididymus situated at the side of the testis. In the Chelonian reptiles the convoluted mass of tube which forms the epididymus is continuous with a very flexuous vas deferens, which is continued as far as the cloaca, into which it opens close to the root of the penis, and in the immediate vicinity of the grooved canal, which, in these animals, represents the urethra.\nIn Saurians the epididymus forms a detached mass of a pyramidal form, which is longer than the testis itself. The vas deferens derived from it, runs along the external border of\nthe kidney as far as the cloaca, into which it opens.\nIn Ophidian reptiles the epididymus is proportionally of smaller size, and is in like manner continuous with a flexuous vas deferens, which terminates in the cloaca.\nThe terminal orifices of the vasa deferentia are always situated in the upper wall of the cloaca, external to or above the ureters, and\nFig. 235.\nHinder Part of the abdominal Cavity of Draco volans.\na a, depressor muscles of false ribs ; b, testes ; c, vas deferens ; d, bladder ; e, rectum.\nare disposed in such a manner, that when the penis is double, the orifice of each vas deferens is close to the commencement of the urethral groove of the corresponding penis when in a state of erection. When the penis is single, both the orifices of the vasa deferentia open in the vicinity of the single urethral canal. In some Ophidians the vasa deferentia, near their termination in the cloaca, dilate into a kind of ampulla, which seems to be a reservoir for the reception of the seminal fluid.\nThe cloaca in the reptilia is a wide cavity which receives the terminations of the rectum, of the ureters, of the allantoid bladder, when that viscus is present, and likewise of the vasa deferentia. In the Chelonians and in the crocodiles, which have a single penis, that organ, when in a state of repose, is entirely concealed in the cloacal cavity, the external opening of which is in these genera an oval or longitudinal opening. In the Chelonians the cavity of the cloaca may be divided into two portions : the one anterior, which is of a cylindrical shape, and receives the termination of the rectum, has its mucous membrane gathered into numerous longitudinal folds, and is surrounded with two layers of muscular fasciculi ; the external assuming a longitudinal, and the internal a circular arrangement.","page":318},{"file":"p0319.txt","language":"en","ocr_en":"REPTILIA.\tsi 0\nThis portion of the cloaca is bounded both before and behind by a ring projecting internally, composed of strong muscular fibres, which form two sphincter muscles.\nThe second portion of the cloaca has its walls thinner than the preceding. The longitudinal folds of the mucous membrane of the first portion suddenly terminate, with the exception of the median fold, which is continued around the termination of the ureter, enclosing it, as it were, between two broad lips, which are then prolonged in the shape of two folds along the median line of the dorsum of the penis, becoming gradually less distinct as the urethral groove which they bound becomes deeper : it is in this second portion of the cloaca that the penis is folded up when in a state of repose.\nIn the crocodiles the disposition of the cloaca is nearly similar, but in these Saurians there exist on each side of the root of the penis two wide apertures, through which a Tree communication is established between the exterior and the cavity of the peritoneum.\nIn the caiman (Alligator sclerops) the cloaca is divided into three compartments, the anterior of which receives the rectum ; the second contains the orifices of the vasa deferentia, of the ureters, and of the allantoid bladder; whilst the third is appropriated to the lodgment of the penis. In this case the dorsal groove of the penis is bounded by' two folds of mucous membrane, which are prolonged backwards into the middle chamber, so as to establish a communication with the openings of the vasa deferentia.\nIn those reptiles which have the penis doubled, viz. the Saurians (minus the crocodiles) and the Ophidians, these organs are not enclosed in the cloaca : in such races the external opening of the cloaca is always a transverse slit, bounded by two lips, the posterior of which is more or less moveable : it is between these lips, just within their lateral commissures, that the two male organs are situated.\nThe posterior lip of the cloaca encloses in its substance a series of orifices which are the openings of the excretory ducts of as many little glands, which seem to represent the anal glands of other vertebrata : they secrete a thick sebaceous matter.\nBesides these, there are in many genera of reptiles a series of crural glands, situated near the orifice of the cloaca ; these exist in all the Lacertid\u00e6. In many Iguanid\u00e6 and other Saurians these glands become largely developed as the season for impregnation approaches.\nIn the Chelonian reptiles the penis is very large, and both in its structure and form somewhat resembles that of the ostrich. It is long, nearly cylindrical in its shape, and enlarged towards its extremity, which terminates in a point. A deep groove extends along the whole length of its dorsal surface, which becomes gradually deeper as it approaches the glans, near the middle of which it terminates by a kind of orifice, divided into\ntwo by a papilla. From the depth of this groove it is evident that the mere approxi-\nFig. 236.\nPenis of the Tortoise. (After Bojanus.)\ne, bulb ; L, corpus cavernosum ; h, urethral groove; k, its termination near the centre of the glans ; i, glans penis ; 55', retractor muscle.\nmation of its edges will convert it into a complete canal.\nThis penis is composed of two corpora cavernosa, the fibrous walls of which are blended together throughout some part of their extent. They commence by two vascular enlargements, analagous to the bulb of the urethra in the penis of mammalia. The erectile tissue is prolonged from this bulb (fig. 236),\nFig. 237.\nMale Organs of Generation of the Tortoise. (After Bojanus.)\na, the rectum ; c, convolutions of epididymus terminating in the vas deferens ; n, which likewise indicates the point where the urethra enters the cloaca ; o, p, the kidney ; y, the testes ; e, the bulb of the urethra ; k, cavernous portion ; m, the urinary bladder ; q, the left supernumerary lateral bladder ; l, r, r', s, x, z, blood-vessels ; 55, retractor muscle of the penis.\nalong two canals, the walls of which are fibrous, and at first very thin ; but they soon increase in thickness considerably, their cavity becoming diminished in the same proportion. All the enlargement that constitutes glans is composed of this vascular tissue, prolonged from th\u00e8 cavernous body, which is covered by a loose and wrinkled skin, and, moreover, supported by a prolongation of the fibrous wall of the corpus cavernosum, which is continued to its point.\nThe skin which lines the urethral groove has also a layer of this erectile tissue placed beneath it ; but this is equally a prolongation from the erectile tissue contained in the cavernous body.\nThere is on each side of the dorsal groove","page":319},{"file":"p0320.txt","language":"en","ocr_en":"320\nREPTILIA.\nof the penis a canal which at one extremity ostrich. There is no erectile tissue discernible communicates with the cavity of the peri- except at the root of the corpora cavernosa,\nFig. 238.\nSection of the Penis of the Tortoise to show its internal Structure. (After Bojanus.')\n10, tendinous floor of urethral groove ; 55tendinous insertions of the retractor muscles of the penis ; f tendinous walls of the urethral groove enclosing the peritoneal canals ; e, lateral cavernous substance of the penis ; 4, median cavernous substance separated from the preceding by the tendinous septum 9 ; 5, urethral groove bounded on each side by the cavernous bodies.\ntoneum on each side of the bladder, and by its other end it is prolonged into the substance of the penis as far as the glans, whei\u2019e it terminates in a cul-de-sac, without being perforated by any orifice throughout its whole extent.\nThe penis of the Chelonians is furnished with two retractor muscles (fig. 239. 55), which arise from the pelvis, and are prolonged as far as the under surface of the glans ; these fold up the organ into the cloaca in such a manner that it closes up the orifice of the rectum, and also that of the urinary bladder, as in the ostrich.\nErection is doubtless produced by the action of the sphincter muscle of the cloaca.\nIn Crocodiles the penis is likewise single, and not enclosed in a sheath like that of other Saurians and of Ophidians. This penis is conical in shape, and is grooved along the whole length of its dorsal region by a deep urethral furrow : it is principally composed of a fibrous and elastic corpus cavernosum, the texture of which is very firm. That portion which represents the glans is softer than the rest, being composed of vascular and erectile tissue : it advances above the apex of the corpus cavernosum, and is prolonged beyond it, so that there are two points thus formed, one situated above the other ; these points are united together on each side, and also in the middle by a vertical septum which divides the interspace between them into two culs-de-sac. The urethral groove is continued as far as the extremity of the upper point.\nThe substance of this penis is, generally speaking, solid, and composed of a very dense fibrous substance, without any intermixture of erectile tissue ; in this respect the penis of the crocodile resembles that of the\nFig. 239.\nThe Penis of the Tortoise.\nA b, the rectum ; c, vas deferens ; f, terminations of the vasa deferentia, in the commencement of g, the urethral groove ; h, corpus cavernosum ; i, the glans penis ; k, end of urethral groove ; 55', retractor muscle of the penis.\nfrom which part it is continued along the sides of the urethral fissure as far as the glans, the substance of which it principally forms.\nThe peritoneal canals, which exist in the crocodiles as well as in the Chelonian reptiles, do not in the former enter into the composition of the penis, as they do in the latter ; they merely pass along the base of the penis to open into the cloaca by a wide orifice : neither have they in their course any communication with the body of the penis ; an arrangement very different from that described above as existing in the tortoises, where they terminate in a cul-de-sac in the substance of that organ.\nIn the other Saurians the penis is either doubled or bifurcated, each portion consisting of a conical or cylindrical portion which forms a sheath that during erection becomes unrolled like the finger of a glove, in such a manner that what before constituted a cul-de-sac becomes, when developed, the extremity of the penis. When thus developed, the two penises protrude from the two lateral commissures of the lips which bound the transverse opening of the cloaca ; when, thus protruded, they are generally found to be studded","page":320},{"file":"p0321.txt","language":"en","ocr_en":"REPTILIA.\n321\nwith recurved spines (fig. 233, k). Essentially, these organs are merely a derivation from or a modification of the skin, which is here lined with erectile tissue. When in a state of repose, these organs are inverted and retracted beneath the skin of the tail, immediately behind the anus.\nEach penis is provided with a special muscle derived from beneath the first caudal vertebra ; this muscle is inserted into the bottom of the pouch when the organ is retracted, and serves to retain it in this position.\nThe contraction of the muscles of the tail contributes with the state of erection to make them protrude from the opening of the cloaca.\nIt seems to be an axiom universally applicable, that in those genera of reptiles having the external opening of the cloaca placed transversely, a double penis exists, constructed upon the principle above described.\nEach lateral penis has a longitudinal groove that extends from its base to its extremity, the extremity of which, when the organ is in a state of erection, is continuous with a groove in the cloaca.\nIn those reptiles that have the extremity of the penis bifurcated, as, for example, rattlesnakes (fig. 233, k), the urethral groove, likewise bifurcates, sending a branch along each division as far as its extremity.\nThe armature of the glans varies in different genera ; sometimes it is smooth or simply covered by papillae, or it may be covered with finely pointed spines or cartilaginous plates.\nFemale Generative Organs. \u2014 Thereproduc-Fig. 240.\nFemale Generative Organs of Lizard.\na, ovaria; b, meso-oviduct ; c, opening of fallopian tube; d, oviduct; e, ova contained in oviduct; /, termination of oviduct; g, rectum; h, cloaca.\ntive organs in the female reptilia are constructed upon a plan of great simplicity, consisting merely of the ovaria and oviducts, through which the eggs are conducted out of the body. The ovaria are two in number, and are found situated upon the sides of the spine in the thoracico-abdominal cavity, where they are suspended by a fold of peritoneum, by which they are invested ; they are situated\nVOL.IV.\nfurther backward or forwards in the different orders, according to circumstances. In the Chelonians they are symmetrical upon the two sides, and their shape is flattened, broad, and short; but in the elongated bodies of many lizards, and more particularly in the Ophidians, these organs are long and narrow, and their right ovary is situated considerably in advance of the left.\nThe ovaria of reptiles are constructed in accordance with two different types, each of which will require notice. In the Chelonians the structure of the ovaria resembles that of the birds, and has a racemose appearance ; the ova, as their development proceeds, becoming pedunculated, so that they hang like a bunch of grapes, by pedicles formed from their calyx ; this capsule, when the egg is mature, becomes lacerated along a line that divides the globular ovum, like an equator, into two hemispheres, exactly as in birds, and the ovum escapes into the abdominal cavity, there to be taken up by the oviduct.\nIn the second type of structure, the ovary forms an elongated sac or tube, in the delicate walls of which the ova are developed. As the ovules become matured, they project more or less into the cavity of the ovary ; and when they break loose it is into that cavity they escape, and ultimately make their exit through an opening that is formed at its anterior extremity for that purpose at the proper period. In the former of these kinds of ovary the ovules, in order to escape, have to rupture not only the proligerous membrane or calyx, but also the peritoneal tunic, with which they are enveloped. In the second form, which is common to the Ophidians, the ovules have only to tear through the proligerous membrane, in order to escape into the cavity of the ovary, the peritoneal covering of which gives way at the proper season to allow them a passage out.\nThe oviducts are invariably two in number, and at their commencement are, as in all other vertebrata, completely detached from the ovary. Each oviduct is a membranous tube which is connected by means of a broad me senteric fold of peritoneum to the side of the vertebral column ; it commences by a wide aperture, by which the ovule is taken up ; its walls are at first extremely thin and delicate, but subsequently become thicker and present a glandular appearance. The oviducts of reptiles are proportionally longer than in birds, but they are much puckered and folded up when in the unimpregnated state. Each oviduct is retained in situ by a broad peritoneal fold, which performs the functions of a mesentery.\nThe two oviducts in all reptiles open separately into the cloaca, which thus represents the vulva of mammiferous animals, giving passage to the ova, and likewise receiving the seminal fluid of the male during copulation.\nDuring the passage of the ovule through the oviduct, it progressively becomes furnished with additions to its structure, the formation of which is due to the oviduct itself; a circumstance which will account for the ex-\nY","page":321},{"file":"p0322.txt","language":"en","ocr_en":"322\nREPTILIA.\ntraordinary and apparently unnecessary length of its canal. In the upper part of its course, the walls of the oviduct secrete the albumen, in which the yoke becomes enveloped, and subsequently the membrana putaminis and the egg-shell are supplied by its inferior portions. In correspondence with these changes of function, its lining membrane is found to differ in appearance and structure in different regions of the oviduct. Towards the commencement of that canal (Jig. 65, p), it is exceedingly\nFig. 241.\nOviduct of Emys Europ\u0153us. (After Bojanus.)\na!', commencement of oviduct; nop, canal of oviduct laid open; st, ovum contained in lower part of oviduct, broken to show the yolk, the albumen, and the egg-shell ; b, allantoid bladder ; c d, kidney; e, ureter; f, oviduct; u, termination of oviduct ; m, termination of the opposite oviduct laid open.\ndelicate, gathered into longitudinal folds, and covered with vibratile cilia lower down (o) ; the walls of the oviduct become evidently glandular, and towards its termination (n), where the outer investments of the egg are secreted, it is thrown into broad irregular rug\u00e6, which are continued as far as its termination in the cloaca (m). External to the mucous membrane, there is a stratum of muscular fibres, by the contractions of which the ovum is propelled along the oviduct ; and externally it is invested with a peritoneal tunic that extends throughout its whole length.\nThe oviducts in the reptilia are very extensible, and in many genera are constructed to contain numerous ova at the same time, as for example in lizards (fig. 240, <?).. In serpents, owing to the slenderness of their bodies,\nthe numerous ova thus contained in the oviduct are arranged in a very remarkable manner : those lodged in the right oviduct correspond with an unoccupied space in the left, and vice vers\u00e2 those in the left are lodged in an interspace between the ova contained in the right.\nThe reptilia proper differ in a very important particular from the Amphibia in the manner in which their eggs are fecundated: in the latter, the fertilisation of the ova is effected after their exclusion, so that the envelope of the egg consists merely of a thin chorion: but in the former, where impregnation takes place internally, the ova, after being fecundated, are provided with an external covering, the nature of which varies in different races. Among the Chelonian reptiles, the land and fresh-water tortoises produce eggs covered with a hard calcareous shell like that of birds ; but in the turtles, the outer shell remains soft, presenting a texture something like that of parchment.\nIn crocodiles the egg-shells are calcareous and brittle, but in the generality of Saurians they are flexible and pergamentaceous. In the Ophidians the egg-shells are made up of superposed layers of soft membrane, secreted by the walls of the oviduct.\nSome reptiles are generally but improperly styled viviparous. The common viper, for example, derives its name from the circumstance of its sometimes producing its young alive. In this, and in all similar instances, however, such an occurrence is merely fortuitous, and depends upon the length of time the eggs are retained in the oviduct prior to their expulsion. If they are not expelled before the young are hatched, of course the creatures bring forth their progeny alive ; and the same animal may, from the nature of its food, be made to produce eggs at one time and living animals at another.\nThe females of those reptilia whose males are provided with a single penis are furnished with a clitoris, but in those genera which have the penis double or invaginated, this organ is deficient. In the female Chelonians the clitoris has very much the same structure as the penis of the male, from which indeed it only differs in its smaller proportional size : it is long, grooved throughout its whole length along its dorsum, and terminated by rounded glans on each side: it contains peritoneal canals similar to those of the male, and is moreover provided with muscles resembling those of the male penis, by which it is retracted into the cloaca.\nThefemale crocodiles have likewise a clitoris very similar to the male penis, but of much smaller proportional dimensions.\nDevelopment of the Embryo, \u2014 As relates to the internal structure of the egg, and development of the embryo, the Reptilia differ in no essential circumstance from the warmblooded Ovipara. Within the calcareous or pergamentaceous egg-shell there is a considerable quantity of exceedingly transparent albumen, which so completely fills the shell that no air bubble is to be detected in its","page":322},{"file":"p0323.txt","language":"en","ocr_en":"REPTILIA.\n323\ninterior, except after some of the fluid contents have been permitted to evaporate. The Fig. 242.\nEgg of the Monitor laid open at a late period of Incubation.\na, the yolk; b, the amnion; c, umbilical cord; d, the embryo, remarkable for the beautiful \u201c packing \u201d of its limbs and tail ; e, the pergamentaceous egg-shell. (After Carus.')\nvitellus exhibits a cicatricula, surrounded with a double zone.\nWhen the embryo arrives at a sufficient Fig. 243.\nEmbryo of Emys amazonica. The shell has been removed and the membranes of the egg laid open and spread out.\na, the amnion, turned back so as to display the\nfetus, here represented with its limbs folded up in their natural position; b, the allantois, with its enclosed ramifications of blood-vesse's; c, the yolk, which is in communication with the intestinal canal by means of the vitelline duct, which enters the abdomen through the opening of the navel.\nstate of maturity, the disposition of the allantois and of the vitelline sac is found to be precisely similar to that of these structures in the egg of a bird, as will be at once evident on reference to the annexed figure, representing the anatomy of the ovum of the Monitor at a very advanced state of maturation.\nThe allantoic sac, which serves for the respiration of the embryo during the earlier stages of its growth, is richly vascular, and communicates as usual with the anterior part of the cloacal cavity, the so-called urinary bladder being, in fact, merely a remnant of this apparatus.\nThe vitelline sac communicates freely with the abdominal cavity at the umbilicus, its contents being conveyed into the commencement of the intestinal canal through a ductus vitello-intestinalis (j%. 244, e) : at a still later\nFig. 244.\nAnatomy of a very young Fetus of the Viper ( Vipera Berus'). (After Otto.)\na, the yolk-bag, b, the amnion ; c, the umbilical cord; d, ductus vitello-intestinalis; e, opening of the ductus vitello-intestinalis between the longitudinal folds of the mucous membrane of the small intestines ; f intestine partially laid open and cut across ; g, h, continuation of the intestine as far as the anus ; i, i, rudiments of the ovaria ; k, k, the kidneys ; l, anus.\ny 2","page":323},{"file":"p0324.txt","language":"en","ocr_en":"324.\tREPTILIA.\nperiod the vitelline sac, together with its remaining contents, is gradually taken into the cavity of the abdomen through the umbilical aperture, and before the egg is hatched has entirely disappeared.\nIn Fig. 246. the condition of these parts is\nFig. 245.\nVitelline apparatus of the Fetus of a Viper at a more advanced period,, showing the Yolk partially entered into the Abdominal Cavity.\na, the yolk-bag; b, the amnion; a', portion of the yolk-bag which has passed through the umbilical canal into the cavity of the abdomen ; d, d, ductus vitello-intestinalis running forward to open into the intestine ; g, continuation of intestinal tube ; k, the kidney.\nFig. 246.\nThe Embryo of a Viper just before it is hatched, showing the Condition of the Vitelline System at this Period.\nThe letters a, c, g, h, l, indicate the same parts as\nin fig. 244. ; b, remains of the vitelline sac, taken out of the abdominal cavity, in which it had now become completely closed; d, the ductus vitello-intestinalis shrunk into a very short canal ; /,/, the stomach; h, i, rudiments of the ovaria; k, the kidney.\nrepresented as they appear just before the egg is hatched, the vitelline sac being already completely introduced into the abdominal cavity ; the yolk of the egg, b, now reduced to a very small size, is now seen to communicate with the intestine f, g, by the extremely short passage, d, to which the long ductus vitello-intestinalis, represented in Fig. 244., is now reduced.\nTegumentary System.\u2014 In all reptiles the blood is cold, and the general temperature of the body corresponds with the imperfectly oxygenated state of the circulating fluid ; instead, therefore, of being clothed in hair or feathers, their bodies are invested with plates or scales of horny cuticle, better adapted to their manner and mode of life. In lizards the cuticular covering is cast off at intervals in small detached portions ; but in serpents, where it forms a thin continuous stratum that envelopes the whole surface of the body, it is cast off in a single piece.\nBeneath the cuticle, the skin of reptiles presents the usual structure, consisting of the corium, and of an interposed mucous layer, upon which the various colours of the surface of the body depend, which in some species are of great brilliancy.\nThe chameleon and other lizards are remarkable for the changes of colour of which the surface of the body is susceptible, in accordance with the intensity of the light to which it is exposed, or the nature of the locality in which it happens to be placed. These changes seem to a considerable extent to be voluntary, and under the control of the animal ; and various hypotheses have been framed in order to account for them, but without any very satisfactory result.\nIn the rattlesnakes (Crotalus) the cuticle in the vicinity of the tail presents a very peculiar modification of structure : instead of forming imbricated scales, as in other parts of the body, it is arranged in a series of rings loosely connected together, so as to constitute the remarkable rattle which characterises these dangerous snakes. This singular organ is made up of many pieces, from one to thirty or more, which are perfectly similar to each other in their form, and are articulated together by a very beautiful mechanism.\nThe piece of the rattle immediately connected with the body seems to be moulded on the last vertebra of the tail, which it encloses, and from which it is only separated by an interposed layer of the dermis or true skin, by which it is secreted. Its surface presents three circular elevations corresponding to three protuberances : of these the first, or that nearest to the body of the animal, is the largest ; the other two rings are encased in the succeeding piece, which is connected","page":324},{"file":"p0325.txt","language":"en","ocr_en":"RESPIRATION.\n325\nin a similar manner to the next ring, and so on throughout the series, the posterior two-thirds of each ring being embraced by the following, so that of the three prominent rings that project from each piece the anterior only is visible, the two posterior being contained in the next ring, with the exception of the ultimate one.\nThe two last rings of each piece thus enclosed in the two first of the succeeding retain it in its place; but as the diameter of the former is less than that of the latter, each piece is quite loose and plays freely about upon that which it envelopes. None, except the first, are connected with the skin of the animal by any muscle, nerve, or vessel. It is, therefore, merely an external appendage, moved, as any foreign body would be, when the end of the tail is'tjgitated.\nThe pieces of the organ are formed successively on the skin of the tail, receiving from it the materials necessary for its development, and adhering to it until its growth is complete. A second piece, entirely similar to the first, is formed under it, and detaches it from the end of the tail. It is pushed backwards, leaving between its edge and the skin of the tail an interval occupied by the first ring of the new piece, of which the second and third rings are covered by the first piece. The latter is retained by this connexion, but plays freely round the first piece. A third piece is formed under the second, as that was under the first ; pushing the second backwards, but retaining it by its two posterior rings being included in the cavity of the second piece.\nIf the vertebrae of the tail continue of uniform diameter, all the pieces will be of the same size, and the rattle, consequently, is of one breadth throughout. On the contrary, if the vertebrae grow while the rattle is being formed, the pieces increase in size, and thus the rattle tapers to its end.\nIt is evident from the preceding description that one piece only can be formed at each partial moulting of the end of the tail ; but as we do not know whether these moultings coincide with the general separation of the epidermis from the body, nor the period of their recurrence, the number of pieces not only affords no proof of specific difference, but also indicates nothing about the age of the animal.*\nMusk-gland of the Crocodile.\u2014 In crocodiles there is a peculiar gland lying under the skin of the lower jaw, on each side about its middle. It is small, of a homogeneous whitish tissue, and is covered by a tendinous sheath. It secretes an unctuous blackish-gre}? fluid, smelling most strongly of musk, which accumulates in a small bag that opens externally by a wide orifice.\nAnal glands have also been observed in the crocodile and alligator, as well as in several serpents : they are of considerable size in female colubers, and are situated under the\n* Lacep\u00e8de, Hist. Nat. des Serpens.\ntail, behind the cloaca, near the part occupied by the penis of the males. They contain a thin yellow substance of a very peculiar odour.\nBojanus (Lud. Hen.), Anatome Testudinis Euro-pe\u00e6. Fol. Yiln. 1819\u201421. Mohring (C. A.), Diss. inaug. zoot. sistens Descriptionem Trionichos \u00c6gyptiaci osteologicam. 4to. Berol. 1825. Tiedemann (F.), Anatomie und Naturgeschichte des Drachens. 3 Kpfn. 4to. N\u00fcrenb. Tyson (Ed. M. D.), Anatomy of the Rattlesnake. 4to. Lond. 1751. Heilman (Aug.), Ueber den Tastsinn der Schlangen. 12mo. Gotting. Cloquet, M\u00e9moire sur l\u2019Existence et la Disposition des Voies lacrymales dans les Serpens. 4to. Paris, 1821. Cuvier, Recherches sur les Ossemens fossiles. 4to. Paris, 1821\u201424. Home (Sir Everard), Lectures on Comp. Anat. 4to. Lond. 1814\u201428. S\u00f6mmering (Detmar. Guil.), De Oculorum Hominis Animalium-que Sectione horizontale Commentatio. Fol. Gotting. 1818. Brandt (J. F.) und Ratzburg (I. F. C.), Darstellung und Beschreibung der Artzneygewachse, welche in die neue Preussische Pharmacop\u00e6 auf-genommen sind. Carus, Lehrbuch der vergleichenden Zootomie. 1834. Owen, Odontography. Wagner, Prodromus. Fol. Cuvier, Anatomie Compar\u00e9e. Last edition. 8 vols. 8vo. Paris, 1840. Schlegel, Essai sur la Physiognomie des Serpens. Amst. 1837. Meckel, Syst, der vergleichenden Anatomie. Ferault, M\u00e9m. de l\u2019Acad. des Sciences, torn. iii.\n(T. Fi/mer Jones.)\nRESPIRATION (Germ. Athmung).\u2014Before the nutritious juices of organized bodies can be properly elaborated and rendered fit for maintaining the vitality of the tissues through which they move, it is indispensable that certain chemical changes take place between them and the atmospheric air. All organized bodies, therefore, vegetable as well as animal, require a supply of atmospheric air for the continuance of life, and the amount of this is proportionate to the number and energy of their vital actions. These chemical changes between the nutritious juices of organized bodies and the atmospheric air constitute the important function of Respiration.\nIn studying the chemical actions that occur in respiration in different organized bodies, it is necessary to keep in mind the constitution of the atmospheric air, both in its free state and when dissolved in water. The atmospheric air, in its free state, is, as is well known, chiefly composed of nitrogen and oxygen, in the proportion of about 21 parts of oxygen to 79 of nitrogen by volume ; or by weight, in the proportion of 23\u20191 of oxygen to 76'9 of nitrogen. Dumas and Boussingault, in their accurate experiments*, found the average proportion of these gases to be, by volume, 20'81 of oxygen, and 79\u201919 of nitrogen f ; or by weight, 23*01 of oxygen, and 76'99 of nitrogen. The quantity of carbonic acid gas in the atmospheric air is very much smaller than that of the oxygen and nitrogen. Theod. De Saussure J, in his experiments,\n* Annales de Chimie et de Physique, troisi\u00e8me s\u00e9rie, torn. iii. p. 257. 1841.\nf Or, what would be sufficiently accurate, 20\u20188 oxygen and 79*2 nitrogen.\nI Annales de Chimie et de Physique, tom. xxxviii. p. 411. 1828.\nY 3","page":325},{"file":"p0326.txt","language":"en","ocr_en":"326\nRESPIRATION.\nfound the maximum quantity of carbonic acid gas in 10,000 parts of atmospheric air to be 6* *2, the minimum 3*7, and the average 4\u20199 or nearly 1 part, by volume, of carbonic acid gas in 2000 parts of atmospheric air. Results similar to those procured by Saussure, who experimented at Geneva, have been obtained by Boussingault* * \u00a7 and Thenardf at Paris, Brunner J at Berne, and Verver\u00ff\u2019at Groningen in Holland, so that we have the strongest grounds for believing in their general accuracy. The variable quantity of watery vapour that exists in the atmosphere must also be taken into account in examining the function of respiration. A quantity of ammonia, so small however that its usual proportion cannot be ascertained, is constantly present in the atmospheric air, which, when it descends to the earth dissolved in water, serves, according to Liebig, an important purpose in the nutrition of vegetables. There are, besides the above substances, numerous others in the gaseous form, exhaled from the surface of the earth, too minute to be detected by analysis, but sometimes recognised by their effects upon the living organism. No doubt the miasmata and effluvia, which can inflict such disastrous evils on the human race, are diffused through the atmospheric air.\nThough the proportions of the three gases, viz. nitrogen, oxygen, and carbonic acid, usually regarded as forming the constituent parts of our atmosphere, are not quite uniform at all times and in all places, chiefly from local disturbing causes, yet these differences are to a small extent, when its free circulation is permitted. Dalton || maintained, that in elevated regions the proportion of oxygen to azote is somewhat less than at the surface of the earth; but this is not confirmed by the more recent experiments of Dumas, Boussin-gault, and Brunner. In the experiments of Lewy If and Morren **, the composition of\n* Annales de Chimie et de Physique, tom. x. p. 456. 1844.\nf Referred to in opus supra citatum, tom. x. p. 463. 1844. Thenard\u2019s experiments were made prior to those of Saussure.\nJ Opus supra cit. tom. iii. p. 313. 1841.\n\u00a7 Referred to in opus supra cit., tom. x. p. 462. 1844.\n|| London and Edinburgh Philosophical Magazine and Journal of Science, vol. xii. p. 406. 1838.\nAnnales de Chimie et de Physique, tom. viii. p. 425. 1843. Lewy found the quantity of oxygen in the air near the surface of the North Sea on an average 22*6 by weight in the 100 of air, while the air over the land contained 23 of oxygen in the 100.\n** Annales de Chim. et de Phys., tom. xii. p. 5. 1844. Morren states that the air resting upon the surface of the sea, in calm weather, may contain from 23 to 24 parts, by volume, of oxygen instead of 20\u20188, the usual quantity ; and this increased quantity of oxygen, under the circumstances mentioned, is connected, as we shall see immediately, with the action of the marine vegetation upon the atmospheric air. The experiments of Lewy and Morren are not contradictory ; for in those of the former the air was taken from the surface of the deep sea at some distance from the shore, and in those of the latter the air analyzed had been resting for some time over\nthe air near the surface of the sea differed in its amount of oxygen from that over the land. Saussure detected a somewhat smaller quantity of carbonic acid gas in the air during the day than during the night *, and a larger quantity in the air of the town of Geneva than in that taken in the country three-fourths of a league distant, in the proportion of 100 to 92 ; and Boussingault and Lewy, in their later experiments, observed a similar difference between the air taken from the densest parts of Paris and that of the country, f Lewy detected a considerable increase of carbonic acid gas, no doubt of volcanic origin, in the air of Guadaloupe, but without any diminution in the usual relative proportions of the oxygen and nitrogen. J As a portion of the oxygen of the atmospheric air is combined with carbon to form carbonic acid gas in the respiration of animals, in ordinary combustion, and in numerous other chemical processes going on at the earth\u2019s surface, it is obvious that when individuals of the human species are surrounded by a limited quantity of air which is not renewed so rapidly as it is vitiated by respiration, the proportion of oxygen gas will be diminished and the carbonic acid increased, and this the more rapidly if any other process of deoxidation of the confined air be at the same time in operation. Dalton analyzed the air of a room where 50 candles had been kept burning and 500 people had been collected for two hours, and found that it contained 1 per cent, of carbonic acid gas. \u00ff Leblanc made a number of analyses of the air taken from the rooms of some of the public buildings in Paris. || He collected some of the air of one of the wards of La Piti\u00e9, the area of which was 70,632 cubic feet, containing 54 patients, after it had been shut during a whole night, and procured from it 3 parts of carbonic acid gas, by weight, in the 1000, or about 5 times as much carbonic acid as is usually present in the atmosphere.^ The oxygen gas had suffered a corresponding diminution. In one of the sleeping apartments of the Salp\u00e9tri\u00e8re, the carbonic acid gas amounted to 6 parts, by weight, in the 1000 parts of the contained air, and in another sleeping apartment to 8 parts in the 1000.** In the Amphitheatre of Chemistry at the Sorbonne, the air collected at the end of the lecture furnished 10-6 of carbonic acid, by\npools of sea-water abounding in alg\u00e6, exposed to the sun\u2019s rays.\n* Boussingault (opus cit. tom. x. pp. 464, 465) obtained similar results ; but he admits that more extended observations are required on this point.\nf Annales de Chim. et de Phys., tom. x. p. 470. 1844.\t*\nt Idem opus, tom. viii. p. 450. 1843.\n\u00a7 London and Edinburgh Philos. Mag., vol. xii. pp. 405, 406. 1838.\nIl Annales de Chim. et de Phys., tom. v. n. 223. 1842.\t1\n1 If the usual quantity of carbonic acid in the atmosphere be from 4 to 6 in the 10,000 parts by volume, that is equal to from 6 to 9 of carbonic acid gas by weight.\n** Opus cit., p. 233\u00bb","page":326},{"file":"p0327.txt","language":"en","ocr_en":"RESPIRATION.\nweight, in the 1000. The air collected in the pit of the Op\u00e9ra Comique a short time before the termination of the performance contained 23 ; while in another experiment the air from one of the boxes contained 4* * * \u00a73, by weight, of carbonic acid gas in the 1000. In one of the stables at the Ecole Militaire, the air collected after it had been kept closed for a night yielded P05 in the 100 ; and the air from another which was better ventilated yielded about 2 parts in the 1000, by weight.* If, according to the opinion of Leblanc and others, carbonic acid gas exerts a prejudicial effect upon the vital actions in the human species when it has accumulated to the extent of 1 per cent, in the air to be breathed, the above facts, to which many others might readily have been added, point out the importance of securing sufficient ventilation both in our private and public buildings.\nAs the gases held by water in solution supply the means of aquatic respiration to many animals and plants, a knowledge of the quantity and composition of these gases is also necessary for the full comprehension of the function of respiration. Humboldt and Gay Lussac state that the water of rivers, and distilled water well aired, hold in solution about J^-th of their volume of air composed of about 32 of oxygen and 68 of azote, by volume.f Morren j concludes from his experiments that sea-water contains in solution between J^th and Jfj-th of its volume of air, a quantity sensibly less than that obtained from fresh-water, which usually contains from to\tor\neven ^L-th of its volume.\u00a7 He found that the air obtained from fresh-water under ordinary circumstances, whether distilled and again perfectly a\u00ebrated, or the limpid water of a moderately rapid stream, contains 32 parts of oxygen, and from 2 to 4 of carbonic acid, by volume, in the 100; while the air obtained from sea-water yielded 33 of oxygen and from 9 to 10 of carbonic acid in the 100. The relative proportion of the gases obtained both from fresh and sea-water varies considerably under certain conditions. In fresh-water ponds abounding in plants or green animalcul\u00e6, and in shallow parts of the sea, where numerous\n* According to the experiments of M. Lassaigne (Comptes Rendus, 13th Juillet, p. 108. 1846) the carbonic acid gas, formed by respiration in apartments where the ventilation is very imperfect, is not confined to the parts nearest the floor, but is diffused nearly in equal proportions through every portion of the mass of air in the apartments.\nf Journal de Physique et de Chimie, par Dela-mitherie, tom. lx. p. 158. The percentage of oxygen from the air of water of the Seine was 3T9 ; of distilled water which had again absorbed air, 32-8; and of rain water* 3L0. (p. 159.)\nJ Annales de Chim. et de Phys., tom. xii. 1844.\n\u00a7 M. Lewy (Comptes Rendus, 28th Sept. 1846) states that, in his experiments, one litre (61-027 cubic inches English) of Seine water yielded about 40 Cubic centimetres (2-440 cubic inches) of air, and the same quantity of water from the ocean furnished only 20 cubic centimetres (1-220 cubic inches). The water of the ocean, in consequence of the salts it holds in solution, absorbs much less atmospheric air than fresh water.\n327\nalg\u00e6 flourish, the proportion of oxygen gas may be considerably increased during sunshine, especially if the water be at the same time still. Morren analyzed, in a bright day in July, the gas dissolved in the water of a fish-pond of a green colour, chiefly from the numerous animalcul\u00e6 it contained, and found in that procured in the morning 25, at mid-day 48, and in the evening as much as 61 of oxygen in the 100 parts.* Similar changes, but to a less extent, were detected by Morren in the air of sea-water, and they are chiefly dependant upon the action of the alg\u00e6. In one experiment, performed on a fine sunny day, when the sea was at the same time calm, the air obtained from the water yielded 40 per cent, of oxygen in the early part of the day, and 53\u20196 in the evening. The total quantity of air obtained from both kinds of water varied at different times of the day ; and its increase was chiefly dependant upon the addition of oxygen, the carbonic acid at the same time suffering a decrease, but not in the same proportion, while the nitrogen f seemed to suffer little change. This increase of oxygen will partly contribute to the supply required for the respiration of the numerous aquatic animals which usually frequent the localities where it is evolved, and be partly given off to the superincumbent air, and thus assist in maintaining the purity of the atmosphere.\nNotwithstanding the large quantity of oxygen daily removed from the atmosphere by the respiration of animals and other causes, yet from the great extent of the atmosphere, and the rapid mixture of its different parts, a long period of time must necessarily elapse before it suffers any marked deterioration, even were there no compensating operation in the vegetable kingdom. The oxygen gas in the atmosphere is equal in weight to a column of 7'8 feet of water pressing upon every part of the earth\u2019s surface : and it has been stated that it would require 10,000 years, supposing the earth peopled with 1,000,000,000 of men to produce a perceptible effect upon the eudiometer of Volta, even though vegetable life was annihilated ; and that to suppose all the animals on the surface of the earth could by\n* Opus cit. p. 9. Wohler (Poggendorff\u2019s Annalen der Physik und Chemie, hand lvii. S. 308. 1842) analyzed the gas exhaled from the greyish yellow mass, consisting in a great measure of living infusoria mixed with some conferv\u00e6, which collects in a salt spring at Rodenberg in Hesse, and found it to be composed of 51 per cent, of oxygen, and 49 of nitrogen.\n\u25a0f M. Lewy (Comptes Rendus, 28th Sept. 1846) has observed similar changes, but not to the same extent, in the relative proportions of oxygen and carbonic acid in the air of sea-water under the circumstances mentioned by Morren. According to the results of Lewy, the waters of the ocean contain a small quantity of sulphuretted hydrogen gas, apparently evolved from the bodies of certain molluscous animals, which may be imparted to the air resting upon the surface of the water ; and Dumas, in his report upon Lewy\u2019s Memoir, throws out some remarks on the possibility of the sulphur contained in this gas serving an important purpose in the nutrition of plants.","page":327},{"file":"p0328.txt","language":"en","ocr_en":"328\tRESPIRATION.\ntheir respiration deteriorate the air to the ex~ tent of removing in a century the 8000th part of the oxygen in the atmosphere, is to make a supposition very much beyond the truth*\nRespiration of plants.\u2014 The results of the chemical actions between the atmospheric air and the vegetable kingdom, are chiefly influenced by the presence or absence of light, and the condition of the plants at the time. When a plant is surrounded by the ordinary atmospheric air, and exposed to the sunshine, the green parts of the plant, and especially the leaves, decompose the carbonic acid contained in the atmosphere, seize upon the carbon, and liberate the oxygen ; while the same plant in the dark, not only ceases to decompose carbonic acid, but actually exhales into the surrounding atmosphere a portion of this gas. A quantity of nitrogen gas is also given off by plants along with the oxygen.f Plants, therefore, during exposure to light, purify the air by removing carbonic acid and adding oxygen, while during the night they, like animals, deteriorate the air by exhaling carbonic acid gas. As, however, the quantity of oxygen gas liberated during the day from the decomposed carbonic acid is more than sufficient to counterbalance the quantity of carbonic acid formed during the night, plants on the whole must counteract, either entirely or in part, the accumulation in the atmosphere of the carbonic acid gas formed by the respiration of animals, and in various chemical processes going on at the earth\u2019s surface. Indeed, nearly the whole of the carbon which enters so largely into the formation of the vegetable tissues, appears to be obtained through the decomposition of the carbonic acid of the atmosphere.\nThe parts of a plant which are not of a green colour, such as the roots, &c., absorb oxygen from the atmosphere, and give out carbonic acid gas even in the sunshine ; and this process seems essential to the vigorous growth of the plant. The flowers of a plant also absorb oxygen, and exhale carbonic acid, and the quantity of the latter gas evolved during inflorescence is considerable. The seeds of plants during germination also absorb oxygen and give out carbonic acid.J The\n* Dumas\u2019 Essai de Statique Chimique des Etres Organises, p. 18, 3rd edit. 1844; and Dumas and Boussingault in Annales de Chim. et de Phys., torn, iii. p. 288. 1841.\nf Daubeny, in Philos. Transactions of London for 1836, p. 149 ; and Professor Draper, in London, Edinburgh, and Dublin Philosophical Magazine, vol. xxiii. p. 161. 1843. According to Draper, \u201c when the leaves of plants under the influence of light decompose carbonic acid gas, they assimilate all the carbon, and a proportion of oxygen disappears, at the same time they emit a volume of nitrogen equal to that of the oxygen consumed.\u201d The greater part of the nitrogen evolved comes, he believes, from the decomposition of some nitrogenized constituent of the leaf.\nX The animalcula, especially those of a green colour, seem to exert the same effects upon the atmospheric air under the influence of light as the green parts of plants. Vide observations of Morren and Wh\u00f6ler, already referred to ; and also Ehrenberg, in Poggendorff\u2019s Amialen, band lvii. S. 311.\nFungi evolve carbonic acid gas in large quantity from all parts of their structure, and at all periods of their growth, even when exposed to a bright sunshine, and these plants derive their supply of carbon from the soil in which they grow.* It is also maintained that a quantity of oxygen is absorbed by the surface of plants during spring and summer, to assist in the elaboration of their acids, resins, and volatile oils. We thus perceive that the chemical actions between the atmospheric air and plants are varied, and differ in some important respects from those that occur in animals. Attempts have been made to show that the respiratory function is essentially the same in these two great divisions of the organic kingdom ; that the fixation of carbon and the liberation of the oxygen gas by the leaves, and other green parts of plants during their exposure to the rays of the sun, form a part of their digestive process ; while the evolution of carbonic acid, which proceeds during the day as well as during the night, from seeds during germination, from the flowers, from the surfaces not coloured green, and also, it is asserted, partly from the leaves, is their true respiratory process.f According to others, if the actions of the juices upon the atmospheric air, by which they are changed from the crude to the fully elaborated sap, and rendered fit for the nutrition of the plant, constitute the function of respiration, then the green surfaces, and especially the leaves,\n* Marcet (Biblioth\u00e8que Universelle de Gen\u00e8ve, (Sciences et Arts,) tom. lvii. p. 393. 1834 ; and Annales de Chim. et de Phys., tom. lviii. p. 407. 1835) ascertained that Fungi, when confined in a limited quantity of air for some time, disengage a larger quantity of carbonic acid gas than could have been formed by the combination of carbon with the oxygen which has disappeared from the air : that when confined in nitrogen gas, a small quantity of carbonic acid is evolved, and in some cases a small quantity of nitrogen is absorbed; and that when confined in oxygen gas a larger quantity of this gas is absorbed than what is sufficient to constitute the carbonic acid gas evolved, and that this is replaced, at least in part, by a quantity of azote disengaged from the plants. We thus perceive that if certain of the lower organized bodies, generally regarded as belonging to the animal kingdom, effect the same changes upon the atmospheric air by their respiration as the higher vegetables do, there are, on the other hand, certain of the lower organized plants that resemble in this respect the higher organized of the animal kingdom. Other cryptogamie plants having a green colour, such as the Ferns and Alg\u00e6, liberate oxygen gas when exposed to the sunshine. Tide Morren\u2019s Experiments on Alg\u00e6, already re-ferred to ; and those of Daubeny, upon Ferns and Alg\u00e6, in London Philos. Transact, vol. xlii. p. 166. 1836.\nt Burnett, in the Journal of the Royal Institution of Great Britain, vol. i. p. 83. 1831. Mr. Burnett also maintains that the analogy further holds good \u201c between the functions of respiration and digestion in animals and plants, for to both is carbonic acid deleterious when breathed, and to both is it invigorating to the digestive system when absorbed as food,\u201d p. 100. Professor Draper (London and Edin. Philos. Magazine, 1844) proceeds still farther, and asserts that the whole of the action of the leaves upon the atmospheric air constitutes a true digestive and not a respiratory function.","page":328},{"file":"p0329.txt","language":"en","ocr_en":"RESPIRATION.\nare the true respiratory organs of plants.* Besides, it has been alleged that the evolution of the carbonic acid gas from the leaves during the night is not attended by an absorption of oxygen, as in the respiration of animals ; that it is a mechanical process, having no con-nexion with the nutrition of the plant ; and that it depends upon the carbonic acid absorbed along with the water by the roots and leaves, escaping into the air along with the water evaporated during the periods when the plant, as in the absence of sunshine, is incapable of fixing the carbon.f As the respiratory process in animals forms a part of the great Nutritive Function, for preparing, elaborating, and assimilating the nutritious juices, and as the two functions performed respectively by the digestive and respiratory organs in the higher animals are not definitely separated in the vegetable kingdom, we can readily understand that the same structures in the vegetable kingdom which carry on the process of respiration, may also at the same time assist in the performance of other parts of the nutritive function.\nIn some of the lower organized plants every part of their surface is probably equally efficient in the performance of the function of respiration ; while in the higher plants, though the whole of the external surface may still aid, the leaves are the chief organs of respiration. Botanists are not agreed as to what extent the spiral tubes, usually regarded as analogous to the tracheae of insects, act as organs of respiration. These spiral vessels do not form continuous canals, and do not open upon the stomata, so that the air cannot enter them without having previously permeated a greater or less thickness of vegetable tissue covering them. Their share in the performance of the function of respiration cannot, probably, be great.\nRespiration in animals. \u2014 The function of respiration varies greatly in activity, and in the external form and position of the apparatus by which it is effected, in the different divisions of the animal kingdom. In all animals, except some Infusoria, the nature of the chemical changes between the atmospheric air and the nutritious juices is pretty uniform, and essentially consists in the evolution of carbonic acid gas and the absorption of oxygen. Azote may be exhaled by, or absorbed at, the respiratory organs in small quantities ; but these changes seem to be of secondary importance in the function of respiration, do not appear to be uniform in the same animals at different times, and occasionally cannot be detected. The evidence, however, preponderates in favour of the opinion that a small quantity of azote is exhaled at the respiratory organs.\nThe function of respiration in animals includes two distinct processes\u2014the evolution\n* Cours El\u00e9mentaire d\u2019Histoire Naturelle. Botanique par M. A. de Jussieu, p. 177.\nt Liebig\u2019s Organic Chemistry, translated by Playfair, p. 31. 1840. Hunt\u2019s Researches on Light, p. 194. 1844. Dumas\u2019 Essai de Statique Chimique des Etres Organis\u00e9s, 3rd ed. p. 24. 1844.\nof one gas from the nutritious juices, and the absorption of another ; and while the former is an act of excretion necessary for the maintenance of the purity of the nutritious juices, the latter is an act of absorption necessary for their proper elaboration. These two acts are of equal importance in supporting the vitality of the organism, are so closely linked together, and are so reciprocally dependent for their continued action, that they have been regarded as belonging to the same function, though in a logical point of view they are parts of two distinct functions, viz. 1st, the absorption by the organism of new materials from the surrounding media for completing the elaboration of the nutritious juices ; and, 2dly, the excretion from the organism of those substances which are of no further use, and would even prove prejudicial if retained. Many of the definitions given of the respiratory process are liable to strong objections in consequence of its compound character not having been kept strictly in view. These mutual actions between the nutritious juices and atmospheric air are purely chemico-physical, take place wherever the air and the fluids are brought into contact, and do not require the agency of vitality for their manifestation. When a urinary bladder has been filled with venous blood and placed in atmospheric air, the oxygen of the atmospheric air, and the free carbonic acid in the blood, mutually permeate the coats of the bladder, the oxygen gas being absorbed by the blood, and the carbonic acid escaping into the surrounding atmosphere. This interchange depends upon the strong tendency that different gases have to intermix or diffuse themselves through each other, and as this action in this particular case takes place through a permeable membrane, it may be regarded as a kind of endosmose and exosmose.\nIt necessarily follows, that wherever the nutritious juices of organized bodies are separated from the atmospheric air by tissues permeable by oxygen and carbonic acid gas, the function of respiration may be performed. The energy of this function will be regulated by the following conditions : \u2014 the greater or less thickness and permeability of the tissues interposed between the atmospheric air and the nutritious fluids ; the quantities and constitution of these substances thus brought into action ; the extent of surface over which they operate ; and the rapidity with which fresh portions of both are brought into contact, in the place of those W'hose mutual actions have been completed. In the higher animals, where this function is performed in greatest perfection, the apparatus for effecting it is very complicated and extensive, and consists, 1st, of a special organ \u2014 the lungs, affording an immense extent of surface where the blood flows in innumerable minute streamlets only separated by very thin membranes from the atmospheric air ; 2dly, of an assemblage of muscles, bones, and nerves, for efficiently renewing the air in the lungs ; and, 3dly, of a series of vessels with a contractile propelling organ attached to them \u2014 the pulmonary arteries and veins and right side of the heart, \u2014 for rapidly","page":329},{"file":"p0330.txt","language":"en","ocr_en":"330\nRESPIRATION.\nchanging the blood in the lungs, and bringing successive portions of it into contact with the atmospheric air. On the other hand, in some of the most simple forms of animal life, which, with the exception of some of the entozoa, are all aquatic, the function of respiration is effected by the external surface, and they have no special organ for exposing their nutritious juices to the action of the atmospheric air, no apparatus for bringing fresh supplies of the surrounding fluid into contact with their bodies, and no canals or tubes for securing a more rapid change of those portions of the nutritious juices exposed to the action of the atmospheric air.\nNumerous and interesting modifications of the respiratory apparatus, each wonderfully adapted to the wants of the individual animal, and the medium in which it lives, and in admirable relation to its other nutritive functions, fill up the wide interval between the most complex and the simplest methods of carrying on the function of respiration. This, like the other functions of the body, is, in proportion to the energy of its manifestations, more concentrated upon individual organs chiefly or entirely constructed for this purpose, and it thus becomes more and more specialized as we ascend in the zoological scale.\nThe position of the respiratory apparatus is chiefly regulated by the circumstance of the animal being terrestrial or aquatic, or, in other words, by its supply of atmospheric air being in the gasiform condition, or held in solution by water. In the greater number of aquatic animals, the respiratory apparatus is placed on or near the external surface of the body ; while, in the terrestrial animals, it is situated more or less deeply in the interior of the body. The medium in which the animal lives also influences the size and complexity of its respiratory organs. As the quantity of atmospheric air in contact with respiratory organs of the same extent of surface must be much smaller in aquatic than in terrestrial animals, a more extended respiratory organ is required in the former than in the latter to effect the same amount of respiration, just as a more extended digestive apparatus is required in herbivorous than in carnivorous animals to extract the same amount of nutritious matters from their food. As water cannot furnish to terrestrial animals an adequate supply of atmospheric air, their vital actions are brought to a stand when their respiratory organs are immersed in that fluid, and this the more quickly in those immediately dependant, as the birds and mammalia, upon large and frequent supplies of atmospheric air. The respiratory organs of aquatic animals are, on the other hand, inadequate for the performance of respiration in the atmospheric air, but from very different circumstances. The most obvious of these are, 1st, their respiratory organs, from their external position, are either freely exposed or only partially covered, so that when they are removed from the water into the atmosphere\nthey become dry in consequence of the evaporation of their moisture, and this the more rapidly as there is little or no provision independent of the water in which they live, for keeping these surfaces moist by a secretion, as in air-breathing animals : 2dly, in those cases where the respiratory organ consists of numerous membranous plates or laminae that float apart in the water, and have every portion of their external surface bathed in this fluid, removal into the atmospheric air causes them to fall together, so that comparatively a small quantity of their surface is now in contact with the air. In some of the Crustacea, and in some fishes, as the eels, the branchiae, or respiratory organs, being covered to a great extent, desiccation proceeds slowly, and life may be prolonged for a considerable time in the atmospheric air. In one of the groups of the Crustaceans, the land-crabs or Gecarcinians, though the respiratory organs have a close resemblance to the branchiae of the aquatic tribes, yet as they inhabit damp situations, and have a provision for keeping the respiratory surface moist, they are enabled to live as terrestrial animals.\nIt has already been stated that the respiratory apparatus in all the higher animals consists of three distinct parts ; \u2014 of an expanded membrane, through which the atmospheric air and the nutritious fluid the blood, act chemically on each other ; of organs for renewing the atmospheric air in contact with the external surface of this membrane ; and of organs for circulating the nutritious fluid along channels placed upon the inner surface of this membrane. Of these three portions of the respiratory apparatus, the first, or the expanded membrane, which may be termed the respiratory membrane, is the most essential, and the other two may be considered as merely accessory to it. In those animals, as the Infusoria, the Polypes, &c., that have no special organs of respiration, the surfaces, bathed by the fluids in which they live, act as a respiratory membrane: the atmospheric air in the surrounding fluids is there brought into contact with the nutritious juices, and the function of respiration is effected in the feeble manner in which it is manifested in such animals. In those animals possessing special organs of respiration, the respiratory membrane is formed in almost all cases by prolongations, folds, or reduplications of the internal or external tegumentary membrane, and all of these different arrangements are evidently with the view of increasing the extent of surface of that membrane. In the pulmograde Medusas the margin of the disk, though smooth, and presenting no prolongation of the external tegumentary membrane, acts more efficiently in the function of respiration than the other parts of the surfaces of the body, and may be considered as a respiratory organ, in consequence of a large quantity of the nutritious juices flowing through numerous vessels distributed there. In some of the Echinodermata, as in the starfishes (Asterid\u0153), and in the sea-urchins (Eclii-","page":330},{"file":"p0331.txt","language":"en","ocr_en":"RESPIRATION.\t331\nr\u00f9d\u0153), the internai integumentary membrane is materially aided in the performance of this function by the aquiferous canals in the former, and by the peritoneal cavity in the latter ; indeed, the peritoneal cavity may be considered the special organ of respiration in the Echinid\u00e6.\nThe respiratory membrane, in most cases, presents one of three forms, which have received the names of gills or branchi\u00e6, of trache\u0153, and of lungs. In the gills or branchi\u00e6 the tegumentary membrane is prolonged outwards, in the shape of laminae, tufts, or branches ; and this arrangement is found in aquatic animals. This form of the respiratory membrane is not, however, universal in those aquatic animals possessing special organs of respiration. In the Ho-lothuridae, one of the tribes of the Echinoder-mata, the chief respiratory organ consists of two aquiferous tubes, of an arborescent form, that open upon the surface of the cloaca.*\nIn the Ascidians, among the Mollusca, the chief respiratory organ is a large cavity, regarded by some as a dilatation of the oesophagus ; and in certain of the aquatic Gasteropoda it consists of a sac, with lamellae on its inner surface, opening upon the external surface of the body. The small cavities placed along the sides of the body of the leech, and opening externally, are also believed to be respiratory organs.\nThe arrangement of the respiratory membrane, termed tracheae, is present in the Arti-culata, among the Myriapods, insects, spiders, and also, with a few exceptions, among the larvae of insects living in the atmosphere ; and is observed in greatest perfection in the adult insects. It consists of a prolongation of the external membrane into the interior of the body, in the form of tubes, often extensively subdivided and ramified, kept open by fibres rolled round their walls in a spiral manner, and commencing at the external surface of the body by orifices termed stigmata. In certain of the larvae of insects, this arrangement of the respiratory membrane is modified to adapt it for aquatic respiration. In the larvae of the Ephemera, these tracheae, instead of terminating in stigmata, are prolonged outwards into a foliaceous expansion of the external integument, where they are subdivided and ramified, and terminate in shut extremities. A constant interchange between the air in the tracheae of these larvae, and the atmospheric air dissolved in the water, will go on through the membranes interposed between them.f In the larvae of the Libella the tracheae are distributed in a similar manner in a membrane placed within the anus, and the animals draw in and expel the water with considerable force from that cavity, so\n* This form of the respiratory apparatus has been termed c\u0153lobranchiate by Straus-Durckheim, being derived from stoixos, hollow ; and \u00df?^yx,x, gill.\nf This modification of the tracheal respiratory organ has been designated tracho-branchiate by Straus-Durckheim.\nthat these respiratory movements act at the same time in causing locomotion.\nThe arrangement of the respiratory membrane called lungs consists of the prolongation of the tegumentary membrane inwards in the form of sacs, and is destined for aerial respiration. In some of the terrestrial gas-teropodous Mollusca, the lung is formed by a single, large, and simple sac, opening by an orifice on the right side of the body. In the Arachnida the lungs are composed of two or more separate cavities, lamellated on their interior, opening on the external surface of the body, and are analogous to the branchial cavity in some of the aquatic Gasteropoda. In all the air-breathing Vertebrata, the respiratory membrane is formed by a prolongation of the internal tegumentary or mucous membrane from the upper part of the digestive tube, and this also holds in the aquatic Vertebrata, or the fishes. When the expanded respiratory membrane is placed at some distance from that portion of the mucous membrane of the digestive tube with which it is continuous, as is especially the case in the Mammalia and birds, this mucous membrane is prolonged to the part where its expansion occurs, in the form of a tube, strengthened on the outer surface by elastic textures to enable it to withstand the atmospheric pressure. Along this tube (trachea), and its branches (bronchi and bronchial tubes), the air passes to and from the proper respiratory membrane on the inner surface of the lungs. In the water newt the lungs consist of a pair of elongated sacs, without any internal lamin\u00e6 or folds. In the frog these membranous sacs present ridges on their inner surface, especially at the upper part; and in the lungs of the turtle and crocodile these ridges increase in number and in size, and form partitions dividing the interior of the lungs into numerous cells communicating with each other.\nIn birds the bronchial tubes on entering the lungs have numerous parietal cells on their inner surface; and this extension of the respiratory surface is still further increased by some of the tracheae opening into membranous bags, often presenting a cellular appearance, and communicating with the interior of certain of the bones. In the lungs of man and the other Mammalia, the bronchial tubes divide and subdivide into minute branches, each of which ends in a cluster of terminal cells, forming one of the small lobes into which the lung may be divided. By this arrangement an immense extent of respiratory surface is packed up in a small space.*\n* Hales (Statical Essays, vol. i. p. 242. 1769) estimates the inner surface of the whole lungs in the calf at 289 square feet, equal to 19 times the surface of a man\u2019s body ; and Lieberkuhn calculates (as quoted by Schultz in his System der Circulation, p. 288) that the whole surface of the air-tubes and air-cells in the human species amounts to 1400 square feet. Monro, on the other hand (Essays of Monro Secundus, p. 59. Edinburgh, 1840) calculates that the inner surface of the human lungs is only equal to 440 square feet, or nearly thirty times","page":331},{"file":"p0332.txt","language":"en","ocr_en":"332\nRESPIRATION.\nIn those animals possessing special organs of respiration, this function is not necessarily restricted to these organs ; on the other hand, there are generally other parts of the organism which serve as auxiliary organs of respiration. We have already seen that respiration may take place wherever the atmospheric air and the nutritious juices are not separated by tissues impermeable to gases. When these tissues are feebly permeable by gases, or when the quantity of nutritious juices in these tissues is small, their respiratory qualities must be feeble, however abundant the amount of atmospheric air in contact with them may be : while under more favourable physical conditions of the tissues, the amount of respiration effected may be considerable. We can readily understand, therefore, how the external cutaneous surface in fishes and in the batrachian reptiles may considerably assist the special organs of respiration ; and how, in some fishes, the mucous surface of the digestive tube may act as an accessory organ of respiration when they rise to the surface of the water, and swallow a quantity of air. As in the crocodiles, and in certain cartilaginous fishes, there are apertures by which the water may enter the peritoneal cavity, it is believed that in these animals the large abdominal serous membrane, which is the chief respiratory organ in the Echinida, serves as an auxiliary organ of respiration.* * In fishes the air-bladder, formed by a prolongation of the internal tegumentary membrane, and constituting a rudimentary lung, is generally considered to be an accessory respiratory organ. Even in the higher Mammalia, the external tegumentary membrane, and the internal tegumentary membrane of the digestive tube, but more especially the former, may be regarded as auxiliary organs of respiration, but the aid they afford to the special respiratory membrane in the lungs is so feeble, that in a practical point of view they may in most cases be disregarded, and they can under no circumstances supply the place, even for a brief period of time, of the special respiratory membrane.\nA moist condition of the respiratory membrane appears to be essential to the proper performance of its functions, and this is obtained in those animals which breathe atmospheric air, by its deep position, and by the fluid secretions poured out upon its surface.\nThe structure of that portion of the respiratory apparatus which acts in bringing fresh supplies of atmospheric air into contact with the respiratory surface, is chiefly regulated by the animal being terrestrial or aquatic, and by the amount of respiration required. In many of the lower aquatic tribes the respiratory surface is external and floats in the water, and any movements on the part of the animal,\ngreater than that of the whole external surface of the body.\n* In the Holothuria the tentacula appear to act as auxiliary respiratory organs. I have observed an active circulation of the nutritious juices in the tentacula of the Ocnus brunneus of Forbes.\nand currents in the water, must change, more or less rapidly, the fluid in contact with the respiratory surface. In such cases, the only structural provision for promoting such movements in the water, is the presence of numerous cilia on the surface of the respiratory membrane, which by their incessant action produce currents in their neighbourhood. In those aquatic animals, where the respiratory organ assumes the form of branched tubes or of cavities, the water in their interior is constantly undergoing a gradual renewal by the incessant action of the cilia upon the inner surface, and it is at other times expelled or renewed much more rapidly by the action of the surrounding contractile tissues. In some of the Crustacea where the branchiae are lodged in a cavity placed under the lateral portions of the carapace, the renewal of the water is effected by the movements of distinct appendages, belonging more especially to the masticatory and locomotive organs ; and in the Cephalopoda, where the branchiae are placed in a cavity beneath the mantle into which the rectum and generative organs also open, the water is chiefly renewed by the contractions of the mantle. In fishes, whose demand for atmospheric air is greater, a complicated apparatus of muscles, bones, and nerves is arranged around the branchiae, for keeping up a constant stream of water over the respiratory membrane. In insects the air in the tracheae is chiefly renewed by the contractions and dilatations of the abdominal segments of the body.\nIn all the vertebrata that breathe by lungs, the muscles for renewing the air in contact with the respiratory surface are numerous, are called into action involuntarily and by excitations conveyed through the nervous system, and contract more or less frequently according to the wants of the organism. In batrachian reptiles, where the ribs are wanting, and in chelonian reptiles whose ribs are soldered together and immovable, the air is not drawn into the lungs, as in birds and the Mammalia, by the dilatations of the walls of the cavity enclosing them, but it is forced into the lungs chiefly by the action of the muscles attached to the hyoid bone as by a forcing-pump, from which it is again expelled chiefly by the abdominal muscles, as in the Mammalia and birds. *\nThe manner in which the nutritious juices are carried to and from the respiratory membrane is usually regarded as a part of the function of the circulation, and has already been described in the article on that function. The position and extent of the respiratory membrane, and the degree of activity required of it, are the circumstances that chiefly influence the arrangement of this portion of the circulatory apparatus, and the quantity and velocity with which the nutritious juices are circulated through it. When the respira-\n* Detailed accounts of the respiratory organs in the different divisions of the animal kingdom are given in the articles under these heads. See also the article Palmo, supplement.","page":332},{"file":"p0333.txt","language":"en","ocr_en":"RESPIRATION.\n333\ntory membrane is closely packed in a particular part of the organism, and the function of respiration is at the same time energetic as in the Mammalia, the blood is circulated with great activity, and in great quantity, through vessels distributed in this membrane, and appropriated solely to this purpose. When the respiratory membrane is extensively diffused, as in insects, throughout the organism, and the atmospheric air is brought into contact with it in the different tissues, a particular set of canals for carrying the nutritious juices to and from the respiratory membrane is not required ; and were we, in such animals, to examine the circulatory apparatus without any reference to the nature of the respiratory apparatus, we could not understand how a circulatory apparatus, apparently so imperfect, is yet equally efficient in carrying on the nutritive processes as in other animals where its mechanism is much more complicated.\nApparatus for renewing the air in the lungs in the human species.\u2014 In man, as in the other Mammalia, this consists of three distinct parts : \u2014 1st, of a movable framework composed of articulated bones and cartilages, but chiefly of the former, termed the thorax ; 2dly, of muscles for enlarging and diminishing the capacity of the thorax ; 3dly, of nerves through which the movements of these muscles are excited and regulated. The uses of this apparatus are not, however, restricted to respiration. The bones of the thorax furnish a certain degree of protection to the lungs, heart, and other important parts enclosed by them ; and during certain violent efforts of the voluntary muscles, as in lifting a weight, they are no longer mobile as in the respiratory movements, but are rendered fixed, and afford a firm and steady point d\u2019appui to the powerful muscles passing between the external surface of the thorax and the thoracic extremities, during their contraction. The same muscles which act involuntarily in dilating and contracting the chest in respiration, are frequently engaged in the performance of voluntary muscular movements, as in articulate speech, straining, &c. They also, in connexion with other muscles, or even alone, perform various involuntary muscular movements which are not respiratory, as in the excito-motory movements of coughing, sneezing, defecation, and urination, and in the sensational and emotional involuntary muscular movements of laughter, sighing, yawning, vomiting, &c.\nThe thorax can be enlarged in all its diameters by the action of its muscles, \u2014 in the vertical or atlanto-sacral, in the antero-pos-terior or vertebro-sternal, and in the transverse. Its enlargement in the antero-posterior and transverse directions is effected by the elevation of the ribs, and its enlargement in the vertical direction by the descent of the diaphragm, and by the elevation of the upper part of the thorax, but chiefly by the former. As the ribs in the human species differ in length, in the degree of their inclination to the spine,\u201c in the form and extent of their curvature, in the manner in which the anterior\nextremities of their cartilages of prolongation terminate, and in some other anatomical points which must influence their mode of action, the phenomena attending the elevation of the ribs are not the same over all parts of the chest, but it will be sufficient for our present purpose to state the general effects of these movements.* As the osseous arches formed by the ribs are so inclined upon the vertebral column that their lower edges form acute angles with that column, and their anterior or sternal are placed lower than their vertebral ends, and as their vertebral or posterior ends have a very limited extent of motion f, their elevation brings them to or near the horizontal plane, and carries forward their sternal extremities ; and as the greater number of the ribs are attached to the sternum through their cartilages of prolongation, this bone must by this movement be pushed forwards, and the antero-posterior diameter of the thorax be enlarged.\nThe transverse diameter of the thorax is increased by the circumstance that the ribs during their elevation do not simply ascend, but perform a slight rotation round an axis passing between their anterior and posterior extremities, by which two effects are produced ; 1st, their lower, which form a segment of a somewhat larger circle than their upper edges, are turned somewhat outwards, and the upper slightly inwards, so that the concavities of the arches formed by the ribs are now perpendicular, or nearly so, to the median plane of the body, instead of being oblique as before their elevation ; 2dly, the middle portion of the greater number of ribs, which before was placed below a straight line passing through their two extremities, in consequence of the shaft of the rib bending upwards near the sternal end at what has been termed the anterior angle, is now placed on the same plane with the two extremities, and the whole rib rendered horizontal. This rotatory motion is greater at the middle of certain of the ribs as they rotate upon their two extremities, so that each rib in the performance of this movement may be considered as forming two levers, the two extremities being the pivots, and the middle of the ribs the ends of the levers most remote from the pivots.J The forward movement of the sternum is greater at its lower than at its upper part, in consequence of the greater length and inclination of the lower vertebro-sternal or true ribs, and the greater length of their cartilages, and the more acute\n* Mr. Sibson has lately (Philos. Transact, of London, Part IV. for 1846, p. 528) given an elaborate analysis of the movements of the thorax in respiration. Dr. Hutchinson has also lately (Me-dico-Chirurgical Transactions of London, vol. xxix. 1846, p. 183) published some of the results of his observations on this subject.\nf According to the observations of Haller (Element. Physiologie, tom. iii. p. 23. 1766) the greatest movement at the vertebral extremity of a rib is scarcely the one-sixth part of a line.\nJ These observations do not apply to the inferior ribs, especially the two last or floating ribs, as they are depressed in inspiration, and not elevated.","page":333},{"file":"p0334.txt","language":"en","ocr_en":"RESPIRATION.\n334-\nangles formed by their articulation with the sternum ; and this difference in the extent of movement in the two portions of the sternum must be still greater before the manubrium and the body of the bone are united by ossifie matter. * * * \u00a7 Though this description of the movements of the sternum in respiration, which is that given by Haller -f-, has been called in question by some modern anatomists, there can be no doubt of its correctness, for it can be proved, by an appeal to the mechanism of the thorax, that, in the upward and forward movement of this bone, its upper and lower ends will pass through paths which differ considerably in their curvature and direction. J Though Haller was wrong in maintaining that the first rib is almost immovable in these actions of the thoracic walls, yet there can be as little doubt that Magendie is in error in asserting that this is the most movable of all the ribs ; for however favourable the nature of its vertebral articulation may be for motion, this is counteracted by the mode in which its cartilage of prolongation is united to the sternum. \u00a7\nThe position and form of the diaphragm is well adapted for enlarging, by its contraction, the vertical diameter of the thorax ; and being placed in the most capacious part of the thorax, even a slight elongation of the vertical diameter there will add considerably to the area of its inner surface. The convex or upper surface of the diaphragm, in its relaxed state, projects upwards on each side of its central or cordiform tendon into the thorax, and is higher anteriorly than posteriorly, and on the right side than on the left. This cordiform tendon is made a fixed point for the arched fibres that run from it to the ribs during their contraction, since it is pulled upon from below and behind by the two crura of the diaphragm, and in front by the short muscular fibres which pass to it from the point of the sternum and the lower edges of\n* During the elevation of the ribs the elastic cartilages of prolongation of the sternal ribs undergo a certain amount of torsion, and the angles they form with the sternum become less acute. The enlargement of the chest produced by the elevation of the ribs is greater in the antero-posterior than in the transverse diameter, and the enlargement in the transverse direction is much greater at the anterior than at the posterior portion of the chest, from the mode in which the ribs are articulated with the vertebral column.\nt Haller (M\u00e9moire sur plusieurs Ph\u00e9nom\u00e8nes Importantes de la Respiration. Lausanne, 1758) found that the upper edge of the sternum was carried forwards 2^, and the lower end from 3 to 8 lines, in a moderate inspiration.\nJ Ward\u2019s Human Osteology, p. 212. 1838.\n\u00a7 The elasticity of the cartilaginous and osseous portions of the walls of the thorax will afford considerable resistance to the muscles in dilating it during inspiration. From the results obtained in two experiments upon the chest after death, Dr. Hutchinson calculates (Medico-Chirur. Transact, of London, vol. xxix. p. 205. 1846) that the force which the muscles of inspiration have to overcome in ordinary breathing from this source is probably, at least, equal to about 100 lbs., and in deep inspiration to about 300 lbs. In these calculations the additional resistance from the elasticity of the lungs was not taken into account.\nthe cartilages of the ribs. If the lower ribs have been previously rendered steady by the action of the quadrati lumborum and serrati postici inferiores muscles, the arched muscular fibres of the diaphragm have another fixed point during their contraction. As the heart rests on the upper surface of the cordiform tendon, and the base of the lungs on the upper portion of the arched part of the diaphragm, the descent of the arched muscular fibres and their change to the horizontal position, causes a considerable enlargement of that part of the chest occupied by the lungs, while the position of the heart is comparatively little affected when the respiratory movements are moderate; but during forcible inspiration the heart recedes deeper into the chest, and during expiration it again comes forward. * The vertical diameter of the chest may be increased in inspiration by the pulling up of its superior portion, by the strong muscles of the neck attached to it, at a time when the lower portion is prevented from ascending, but an increase in the vertical diameter by an elongation of its upper part must have a much less effect in enlarging its capacity than an elongation of its lower part seeing that the thorax is at least four times as large at its lower as at its upper end. In ordinary respiration, and when the body is at rest, the ribs move little in the male, muscular movements of inspiration ai \u201ey carried on by the diaphragm.-)-\nThe ribs are elevated, in ordinary respiration, by the levatores costarum, external and internal intercostal muscles J, and also, more\n* In the article Heart, Yol. II. p. 578, in stating this circumstance, the word inspiration was inadvertently used for expiration, and vice, versa.\nt Dr. Hutchinson (Medico-Chirurg. Transact, of London, vol. xxix. p. 187. 1846) by a delicate instrument measured the costal movement during ordinary respiration in healthy individuals of the male sex, and found it not to exceed from two to four tenths of a line. The costal movements in the female sex, especially at the upper part of the chest, are considerably more extensive. Dr. Hutchinson states that the difference between the circumference of an ordinary man\u2019s chest measured over the nipples in the two states of a deep inspiration and a deep expiration, amounts to 3 inches (Opus cit. p. 222) ; and Valentin, under the same circumstances, found the average difference in the circumference of the chest, measured over the scrobiculus cordis, in seven individuals of the male sex between 17J and 33 years of age, to be 1:8-29 of the whole circumference. (Lehrbuch, &c. erster band, S. 541. 1844.) In old age, when the costal cartilages of prolongation become ossified, the mobility of the chest must be diminished.\nX The mode of action of the intercostal muscles has been a subject of discussion since the time of Haller, \u2014many entertaining the opinion of Haller, that both the internal and external sets act simultaneously as muscles of inspiration ; some, that they are muscles of expiration ; while others, again, assert that one set act during inspiration, and the other set during expiration. Those who maintain the last opinion are not agreed among themselves as to what set act as muscles of inspiration, and what as muscles of expiration. The mode of action of these muscles has lately been carefully examined by MM. Beau and Maissiat and Mr. Sibson (Opus bit.) ; and the two former (Archives G\u00e9n\u00e9rales de M\u00e9decine, 4 s\u00e9rie, tom. i. p. 268. 1843), conclude","page":334},{"file":"p0335.txt","language":"en","ocr_en":"RESPIRATION.\t335\nespecially in the female, by the scaleni muscles. When the respiration becomes hurried or more laboured, the diaphragm and the muscles that elevate the ribs not only act more vigorously in inspiration, but numerous other muscles, which may be termed auxiliary muscles of inspiration, act in unison with these.* * In cases of great dyspnoea, as in a fit of asthma, the shoulders are fixed, the head is thrown back, and all the auxiliary muscles of inspiration are brought into violent action. When the shoulders are fixed by the action of the levatores anguli scapul\u00e6, the rhombodei majores et minores, and the humeri also fixed by the scapulo-humeral muscles, or by the person grasping some fixed object by the hands, then the muscles, or portions of them which pass between the thoracic extremities and the anterior and lateral walls of the chest, as the serrati magni, the pectorales minores et majores, the subclavi, and perhaps the costal portion of the latissimi dorsi, act as muscles of inspiration, by pulling the ribs upwards and outwards f ; and when the head, cervical vertebrae, hyoid bone, and larynx are fixed by the numerous muscles capable of performing this action, then the sterno-cleido-mastoidei, the sterno-hyoid, and sterno-thyroid muscles, may aid the scaleni muscles in drawing the superior part of the thorax upwards.^ The rrr ? b postici superiores, and the cervicales Rentes, are also accessory muscles of inspiration, if the former be not, at times, in fact a muscle of ordinary inspiration. The superior aperture of the larynx is dilated during inspiration by the crico-arytenoidei postici muscles when the breathing is in the least\nthat both sets are muscles of expiration, while the latter maintains the more probable opinion, that they act differently in different parts of the thorax. Dr. Hutchinson has also lately made some observations on the actions of these muscles in Medico-Chirurgical Transact, of London, vol. xxix. p. 213.\n[Dr. Hutchinson regards the external intercostals and the intercostilaginous portion of the internal intercostals as muscles of inspiration, while the rest of the internal intercostals are muscles of expiration. See a further exposition of this author\u2019s views in the article Thobax. \u2014Ed.]\n* According to Dr. Hutchinson (Opus cit. p. 187) the chief enlargement of the thoracic cavity in deep inspiration is made by the ribs, and not by the diaphragm.\nf Part of the muscles passing between the thoracic extremities and the anterior and lateral walls of the chest, here enumerated among the accessory muscles of inspiration, may, in certain cases, act as accessory muscles of expiration, by drawing the scapul\u00e6 forcibly downwards upon the ribs. (Vide observations of Mr. Sibson and MM. Beau and Maissiat.) These authors are not of the same opinion regarding the action of all these muscles ; for, while the two former class the serratus magnus among the muscles of inspiration (Opus cit. tom. iii. p. 268. 1843), the latter affirms that the greater portion of its fasciculi acts visibly in violent expiration (Opus cit. p. 535) : they agree, however, in placing the latissimus dorsi among the accessory muscles of expiration.\nJ The hyoid bone, larynx, and trachea are sometimes drawn downwards during violent inspirations by the strong contractions of the sterno-hyoid and sterno-thyroid muscles, causing a depression of these parts, at the same time that they elevate the sternum.\nhurried ; and in laboured breathing the nostrils are expanded by the contraction of the muscles, which draw the al\u00e6 of the nostrils outward. The greater or less demand for fresh air in the lungs regulates the number of these accessory respiratory muscles brought into play, and the energy of their contraction.\nA diminution of the capacity of the thorax or an act of expiration, by which part of the air is expelled from the lungs, follows immediately each inspiratory movement. In ordinary respiration, after the muscles of inspiration have ceased to contract, the elasticity of the thoracic walls, especially of the cartilaginous portion, causes it to return to the state in which it was before its dilatation ; and when the contracted diaphragm has relaxed, the elasticity of the parts displaced by its descent, is sufficient, without much, if any, aid from the abdominal muscles, to push the diaphragm again upwards. The gas present in greater or less quantity in the digestive tube, being compressed during the descent of the diaphragm, will, from its elasticity, assist in pushing upwards the relaxed diaphragm.* In more forcible expirations, when the walls of the chest are compressed beyond the state they assume when the muscles of inspiration are relaxed, the compressing muscles experience considerable resistance from the elasticity of the walls of the chest.\nWhen the expirations are performed more forcibly than ordinarily, the diaphragm is pushed up, and the sternum and ribs depressed by the contractions of the three broad muscles of the abdomen, by the recti abdominis, and by the triangularis sterni muscles. The levator ani, one of the antagonist muscles of the diaphragm, assists also in pushing the abdominal viscera upwards. In hurried or laboured expirations the diaphragm is pushed more forcibly upwards by the muscles mentioned, and the ribs are pulled downwards, and the chest compressed, by the quadrati lumborum, serrati postici inferiores f, sacro-lumbales and longissimi dorsi muscles.\nMM. Beau and Maissiat % have described three kinds of ordinary respiratory movements : 1. the abdominal, in which the abdominal walls chiefly act : 2. the costo-inferior, in which the movements chiefly take place in the lower ribs, from the seventh inclusive, downwards : 3. the costo-superior, in which the superior part of the chest is carried upwards by the elevation of the superior ribs and the sternum. The first kind, or the abdominal type, is observed in infants up to the end of the third year in both sexes ; but after this period the costo-superior type in girls, and the costo-inferior and abdominal types in boys, generally prevail, and this difference becomes more marked as they advance in years. Almost all men, therefore, breathe by\n* Maissiat, in his Etudes de Physique Animale, and Beau and Maissiat in Arch. G\u00e9n\u00e9r. de M\u00e9d. tom. iii. p. 263. 1843.\nf Dr. Hutchinson informs us that the body is considerably shortened during violent expiration. (Op. cit. pp. 191, 192.)\nX Archiv. Gen. de M\u00e9d. tom. xv. p. 399. 1842.","page":335},{"file":"p0336.txt","language":"en","ocr_en":"RESPIRATION.\n336\nthe lower part, and women by the upper part of their chest, and this independently of the effects of particular articles of dress ! * * * \u00a7 This difference in the mode of respiration in the two sexes is, in general, maintained even in dyspnoea, unless it be very severe. As the costo-inferior and abdominal types of respiration would be impeded in the female when pregnant, the ordinary costo-superior type of respiration in the female has apparently a reference to that condition.f\nValentin Dr. Hutchinson \u00ff, and Mendelssohn ||, have lately made experiments upon the force of the muscular movements of inspiration and expiration. Those of Dr. Hutchinson are much the most extensive, and are 1500 in number. He found that the power of expiration is nearly one third stronger than that of inspiration ; and he states that whenever the expiratory are not stronger than the inspiratory muscles, that some disease is present. He tested the force of the two classes of respiratory muscles by causing persons to make the most powerful efforts of which they were capable when breathing through the nose into an instrument constructed for the purpose, and the subjects of experiment were taken from individuals of the male sex, following very different occupations. In examining the results of the whole experiments, and including all the thirteen classes of men subjected to experiment, the power of the inspiratory muscles is found greatest in men of 5 feet 9 inches in height, their inspiratory power being equal, on an average, to a column of 2\u201975, and their expiratory power to 3'97 inches of mercury ; while in four of these classes, composed generally of active, efficient, and healthy individuals, viz. Firemen, Metropolitan Police, Thames Police, and Royal Horse Guards, the inspiratory power of the men of 5 feet 7 inches was the greatest, being equal to 3*07 inches of mercury, and those of 5 feet 8 inches to 2 96 (nearly 3 inches). The average power of the 5 feet 7 inches and 5 feet 8 inches men of all the thirteen classes was only 2\u201865 inches of mercury. The inspiratory power of twelve six-feet men in the first battalion of Grenadier Guards was only P92 inches, while that of thirty-one of the same\n* These observations of Beau and Maissiat upon the differences in the respiratory movements in males and females are confirmed by Dr. Hutchinson (Op. cit. p. 195), and they were known so far to Boerhaave and Haller.\nj- These authors also state that this difference in the respiratory movements of the two sexes have impressed upon the chest certain anatomical differences ; for while the intercostal spaces at the upper part of the chest are larger in the female, those at the lower part are larger in the male ; and while the first rib is movable in the female, it is almost or entirely immovable in the male.\nj Lehrbuch der Physiologie des Menchen, band i. S. 524. 1844.\n\u00a7 Journal of the Statistical Society of London, vol.vii. p. 193. 1844; and Medico-Chirurg. Transactions of London, vol. xxix. p. 197. 1846.\n|| Der Mechanismus der Respiration und Circulation, S. 116\u2014120. Berlin, 1845.\nheight in the Blues (Life Guards) was 2\u201871 inches. He infers from these experiments that a healthy man of 5 feet 7 inches or 5 feet 8 inches, should elevate by inspiration 3 inches of mercury. The force of the expiratory muscles is more liable to be affected by the ordinary occupation of the individual than that of the inspiratory muscles, and therefore the state of the former is less to be relied upon in judging of the health of the individual than that of the latter.* The elasticity of the walls of the chest is, no doubt, one cause of the greater force of the expiratory over that of the inspiratory muscles.\nIn inspiration the pressure of the elastic air in the lungs causes these organs to expand, so as to keep their outer surface in contact with the inner surface of the dilating thorax ; and by this the air of the lungs becomes rarified, and a quantity of fresh air rushes along the trachea and bronchial tubes to restore its equilibrium ; in expiration, on the other hand, the lungs are compressed, and a portion of air is forced outward along the same passages. In these movements the lungs are not quite passive. The external surface of the lungs, and of the numerous lobes into which they may be divided, is covered with an elastic membrane, and this, conjoined with the weight of their tissues, must favour the expulsion of the air during expiration, and present a certain amount of resistance to its entrance during inspiration.f\n* Valentin\u2019s experiments upon the respiratory forces were performed upon six males between 18 and 32 years of age. In ordinary tranquil respiration the force of each of the acts of inspiration and expiration was equal to the weight of a column of mercury of from 4 to 10 millimetres (or from T574 to \"3937 of an English inch) ; in the least forcible respiration it ranged between 20, 35, and 40 millimetres of mercury (from *7874, 1*377, and L5748 of an English inch). In ordinary tranquil respiration in the same individual, at different periods, the range of the respiratory force was even more than between 5 and 10 millimetres (or between T968 and \u20223937 of an inch). The average force of an ordinary tranquil respiration, when the nose was held and the individual inspired and expired through the mouth, was 6-45 mill. (-2539 of an inch) ; when they inspired through the nose and expired through the mouth alone, it was 10\u20196 mill. (-4173 of an inch) ; and when they inspired through the nose and expired through the nose and mouth, it was 5 mill. (T968 of an inch), or about one half of the;strength when they expired through the mouth alone. He found that the strongest inspiration of which these individuals were capable was equal to 144-3 mill. (5-6812 inches) of mercury, and the strongest expiration to 204 mill. (84)316 inches) of mercury. Mendelssohn\u2019s experiments were performed upon seven individuals, and they breathed through one nostril, the other nostril and the mouth being shut. He found that the force of the most powerful expiration was greater than that of the most powerful inspiration by about one inch of mercury. The most powerful expirations were on an average between 4-4 and 4*8 inches of mercury. In performing such experiments it is necessary to breathe through the nose, the mouth being shut, as in those of Dr. Hutchinson and Mendelssohn, if we wish to obtain the force of the muscles of the chest, apart from that of those of the cheeks.\nt Dr. Carson (Philos. Trans, of London for 1820, p. 42), states that in his experiments on \u201c calves,","page":336},{"file":"p0337.txt","language":"en","ocr_en":"RESPIRATION.\nWhen the external air is admitted freely into the sac of the pleura, by an opening in the parietes of the thorax sufficiently large to permit the air to pass through it in greater quantities than it can enter the lungs by the trachea, the lung collapses rapidly and is compressed against the spine; and if this take place on both sides of the chest, the respiratory process is arrested, and the individual dies, as from suffocation. When the lungs lose their elasticity, and the air-cells become dilated and their septa partially broken down, as in emphysema, the respiratory membrane is not only diminished in extent, but expiration is more difficult, and when the chest is laid open after death, the lungs collapse imperfectly or not at all. It is evident that still more serious evils must follow interlobular emphysema, or effusion of air into the cellular tissue surrounding the smaller lobes of the lungs, if this occurs to a considerable extent.\nThough the trachea, the bronchii, and even the smaller bronchial tubes are provided with distinct muscular fibres which can be thrown into contraction by direct \u00e8xcitation, and even, according to some experimenters, by excitation of their nerves, yet the notion entertained by many of the older, and even by some modern physiologists, that the lungs have an active power of contraction and dilatation synchronous with and aiding the movements of inspiration and expiration, is undoubtedly untenable. These muscular fibres of the bronchial tubes are endowed with that kind of contractility termed simple contractility, which manifests itself by more slow and prolonged contractions and relaxations than that of the voluntary muscles and the heart,* * The possession of this property of simple contractility unfits these muscular fibres from acting simultaneously with the muscles of respiration moving the thorax, but fits them for effecting these changes on the capacity of the air-tubes, which may aid in the expulsion of substances from their interior, as in coughing. The movements of the cilia placed on the inner surface of the respiratory organs, can assist little, if at all, in renewing the atmospheric air in the lungs. The passage of the air into and from the lung, has an important effect upon the muscular respiratory movements. When a lung, or a considerable portion of it, is prevented from expanding by disease or any other cause, the pressure of the air on the inner surface of that portion of the chest covering the unexpansible\nsheep, and large dogs, the resiliency of the lungs was found to be balanced by a column of water varying in height from one foot to a foot and a half, and in rabbits and cats by a column of water varying in height from six to ten inches.\u201d Vide also Observations by M. P. Berard on the Effects of the Elasticity of the Lungs, in Archives G\u00e9u\u00e9r, de M\u00e9decine, tom. xxii. p. 180. 1830.\n* Yide experiments of Wedemeyer (Untersuchungen \u00fcber den Kreislauf, p. 70), and of Dr. C. J. B. Williams (Transact, of British Scient. Assoc, for 1840, p. 411), upon the contractility of the bronchial tubes.\nVOL. IV,\n337\nlung is not now exercised during its dilatation ; in other words, this portion of the chest in expanding must do so in opposition to the whole of the atmospheric pressure on its outer surface, amounting to 15 pounds on the square inch. This pressure appears to be too great for the muscles of inspiration, acting upon that part of the chest, to overcome, for the ribs are there motionless or nearly so, and if the lung is in a state of collapse, the walls of the thorax covering it fall in.\nThe muscular movements of inspiration and expiration are, in the natural and healthy state of the body, performed without the intervention of volition, and even without our consciousness, and belong to the class of movements which have lately received the appellation of excito-motary. When, however, the free aeration of the blood in the lungs is impeded, a sensation, urgent and imperious in its demands, is felt, which in our language is somewhat clumsily designated \u201c the sensation of the want of fresh air in the lungs,\u201d and more elegantly in French, le besoin de respirer. These respiratory movements, therefore, depend upon the transmission inwards of certain excitations along afferent nerves to the central organs of the nervous system, whence a motive influence is sent outwards along the motor or efferent nerves distributed in the muscles to be moved. One of the principal excitor or afferent nerves of respiration is the par vagum ; and the medulla oblongata is the portion of the central organs of the nervous system to which all the excitations of the nervous system capable of producing a respiratory muscular movement must be brought. The motor or efferent nerves that convey outwards from the medulla oblongata the motive influence which stimulates the muscles of respiration to contract are the phrenic, and part of the anterior roots of the dorsal and lumbar spinal nerves, the recurrent laryngeal, the portio dura, the spinal accessory, and some branches of the cervical and upper part of the axillary plexus besides the phrenic, especially the branch distributed in the serr\u00e2tes magnus muscle, termed by Sir Charles Bell the external respiratory. Some of these efferent nerves, like the muscles in which they are distributed, are habitually engaged in carrying on the respiratory muscular movements, while others aid these only when the respiration requires to be carried on more vigorously than usual.\nWe have already pointed out the extent to which the nervus vagus acts in conveying to the central organs of the nervous system those impressions that excite the besoin de respirer and the muscular movements of inspiration. ( Vide art. Par Vagum.)\nIt is impossible to determine whether or not the pulmonary ganglionic nerves can convey inwards to the central organs of the nervous system impressions capable of exciting the respirator}' muscular movements ; but that impressions capable of exciting such movements to a certain extent may be re*\nz","page":337},{"file":"p0338.txt","language":"en","ocr_en":"338\tRESPIRATION.\nceived by other nerves than those distributed in the lungs, is proved by the fact, which we have witnessed, that a few distinct respiratory movements may be observed in an animal after its lungs have been removed. That portions of the posterior roots of the spinal nerves distributed in the external cutaneous surface do act as excitors of respiration under certain circumstances, is proved by the effects of dashing cold water on the surface of the body, especially on the face. It is also probable that the circulation of venous blood in the arteries of the medulla oblongata may aiso cause the transmission of the motive influence outwards to the respiratory muscles. What are the excitations which lead to the performance of the muscular movements of expiration? Do the same excitations that occasion the muscular movements of inspiration, operate in the production of the expiration which immediately follows, so that they are to be considered two stages of the one and the same muscular action ? These are questions which we are not prepared to answer. When the functions of the medulla oblongata are arrested, the motive influence of volition cannot pass downwards from the encephalon to the motor nerves that move the chest in respiration ; and as all the excited or involuntary movements of respiration of the same muscles must, for the reasons already stated, instantly cease, immediate death is the consequence. Destruction of a portion of the spinal chord below the medulla oblongata and above the origin of the phrenic nerve will also produce the same result, for though the excitations that lead to the performance of the respiratory muscular movements reach the medulla oblongata, the motive influence cannot pass downwards to reach the motor nerves distributed in the muscles which act on the thorax.\nFrequency of the respiratory muscular movements.\u2014 The frequency of the respirations varies in different individuals, and at different ages, and is so much influenced by the condition of the body and the mind at the time, even when the individual is in perfect health, that it is a much more difficult matter to determine their average frequency than may at first be imagined. Quetelet* has constructed the following table on the frequency of the respirations, at different ages, per minute, from observations made on 300 individuals.\n\tInspiration*\t\t\n\tAverage.\tMax.\tMin.\nAt birth\t44\t70\t23\n5 years\t26\t32\t\n15\u201420\t20\t24\t16\n20\u201425\t18-7\t24\t14\n25\u201430\t16\t21\t15\n30\u201450\t18-1\t23\t11\n* Sur l\u2019Homme et le D\u00e9veloppement de ses Facult\u00e9s, &c. torn. ii. p. 91. Bruxelles, 1836.\nMr. Hutchinson* gives the following table of the number of respirations per minute in adults when in the sitting posture, in 1714 adults of the male sex, considered to be in a state of health.\nNumber of\tNumber\tNumber of\tNumber\nRespirations\tof\tRespirations\tof\nper Minute.\tCases.\tper Minute.\tCases.\n6\t1\t26\t8\n9\t1\t27\t2\n10\t2\t28\t30\n11\t1\t29\t2\n12\t19\t30\t6\n13\t10\t31\t0\n14\t21\t32\t6\n15\t12\t33\t0\n16\t216\t34\t1\n17\t95\t35\t0\n18\t181\t36\t1\n19\t70\t37\t0\n20\t510\t38\t0\n21\t120\t39\t1\n22\t136\t41\t1\n23\t41\t\t\u2014\n24\t220\tTotal\t1714\n25\t16\t\t\nFrom Mr. Hutchinson\u2019s table it would appear that the majority of male adults breathe between 16 and 24 times per minute, and that of these a great number make 20 respirations per minute.-)-\nAccording to Pr\u00e9vost and Dumas J, the ratio of the respirations to the pulsations of the heart is as 1 to 4. According to Mr. Hutchinson \u00a7, \u201cthe prevailing numbers run as four beats of theheart to one respiration.\u201d Quetelet|| states, that \u201c it does not appear that there is\n* Medico-Chirurgical Transactions of London, vol. xxix. p. 226. 1846.\nt The following results upon the frequency of the respiration in a state of rest have been obtained by others ; but as these were made upon their own persons, they possess only the value of individual cases. Dalton (Memoirs of the Literary and Philosophical Society of Manchester, 2nd series, vol. ii. p. 26, 1813) found the number of his respirations to be 20 per minute ; Thomson (System of Chemistry, vol. iv. p. 604, 1820), to be 19 ; Sir H. Davy (Researches chiefly concerning Nitrous Oxide and its Respiration, p. 434, 1800), to be 26 or 27 ; Magendie\"(Compendium of Physiology, translated by Milligen, p. 390, 1831), to be 15 ; Dunglisson (Human Physiology, vol. ii.), to be 16 ; and Allen and Pepys, on one of themselves (Philos. Trans, of London for 1808), to be 19. Menzies (Teutamen Physiol. Inaug. de Re-spiratione, 1790), found them to be 14 in the minute in the person on whom he experimented ; Yierordt (Article \u201cRespiration\u201d inWagner\u2019sHandw\u00f6rterbuch der Physiologie, band ii. S. 834), in his own person, found them on an average to be ll-ft when sitting, and the mind disengaged; while their maximum was 15, and their minimum 9. Dr. Guy (Hooper\u2019s Yade-Mecum, edited by Dr. Guy) ascertained that the respirations in his own person were 22 in a minute while standing, 19 when sitting, and 13 when in the recumbent position.\nX Yide Burdach\u2019s Trait\u00e9 de Physiologie, traduit de l\u2019Allemand par Jourdan, torn. vii. p. 38.\t1837.\n\u00a7 Journal of the Statistical Society of London, vol. vii. p. 205.\nIl Op. cit.","page":338},{"file":"p0339.txt","language":"en","ocr_en":"RESPIRATION.\t339\na determinate ratio between the pulsations and respirations ; however, in many individuals, and I am of the number, it is as 1 to 4.\u201d Dr. C. Hooker* informs us that, from numerous careful observations, he has arrived at the conclusion, that the numerical relation between the beats of the heart and the respirations (except in infancy) is as 1 to 4\u00a7, and that any marked deviation from this relation indicates some mechanical or structural impediment to the free play of the lungs. According to Burdachf, the same circumstances which diminish the frequency of one of these movements acts equally upon the other ; but it is proved by the recent observations of Dr. Guy, that these variations do not bear the same proportion to each other. In Dr. Guy\u2019s experiments J, the proportion between the respirations and the pulse has varied from 1 1 2-60 to 1 : 5-23 ; and whereas the pulse becomes less frequent as the day advances, the respiration increases in frequency, so that there are 18 respirations in the evening for 17 in the morning. The chief cause of the variation in the ratio of the respirations and the pulse \u201cis the position of the body. Thus, for a pulse of 64, the proportion standing was 1 : 2-95 ; sitting, 1 : 3*35 ; and lying, 1 : 4*97. In the sitting posture, but from different frequencies of the pulse, it has varied from 1 : 2*61 to 1 : 5*00. The proportions morning and evening for the same frequency of the pulse are about 1 : 3 60 and 1 : 3*40. The proportions which the respiration bears to the pulse decreases as the pulse increases. Thus, for a pulse of 54 the proportion was 1 : 3, for a pulse of 72 it was 1 : 4.\u201d\nQuantity of air drawn into the lungs at each inspiration, and expelled at each expiration; and the quantity of air in the lungs at different times. \u2014 During ordinary respiration in a state of health, and when the body is at rest, a small quantity only of the air which the lungs can contain is exchanged by each act of inspiration and expiration. The average amount of air in the lungs in the state of ordinary respiration, may be considerably increased or diminished by forced inspirations and expirations, but the whole air contained in the lungs cannot be expelled by the most powerful action of the muscles of expiration. The quantity of air drawn into the lungs by each inspiration and again expelled by expiration, in the state of ordinary respiration, not only varies in different individuals, but in the same individual in different conditions of the body, so that the results obtained by physiologists on this point must necessarily be dissimilar, and the more especially as the greater number of these have experimented only upon a single, or a very limited number of individuals. The difficulty of ascertaining the average quantity of air exhaled at an ordinary\n* Boston Medical and Surgical Journal for 1838. Yide also British and Foreign Medical Review, vol. vii. p. 263.\nf Op. cit. p. 39.\nt Hooper\u2019s Vade-Mecum, edited by Dr. Huy, pp. 131, 132. 1846.\nexpiration, and the great range that occurs in this respect, may be judged of by the statement of Vierordt, that the variation in his own person is as great as 1 : 4*75.* The probable average quantity of air drawn into the lungs at each inspiration even in healthy individuals, at different ages and in different states of the body and of the physical conditions under which it may be placed, can only be ascertained by the performance of a much more extended series of experiments than we at present possess ; and the ascertainment of the causes which determine these variations from the average quantity will be still more difficult, and of still more importance. All such experiments are liable to many sources of fallacy, both from imperfections in the instruments used in conducting them, and from the muscular movements of respiration being unwittingly influenced by the attention of the persons experimented upon being fixed upon these movements ; but the later experiments on this point are more trust-worthy than the earlier, as the instruments employed are better suited for the purpose, and by frequently repeating the experiment on the same persons, they at last become accustomed to the artificial circumstances under which they are placed, and they breathe more naturally.\nHerbst, from his experiments, concluded, that a healthy adult of average size should in an ordinary inspiration inhale from 20 to 25 Parisian cubic inches (24*211 to 30*263 English cubic inches), and exhale the same quantity in expiration; while an individual of a feebler constitution of body should inhale from 16 to 18 Parisian cubic inches (19*368 to 21*789 English cubic inches).j* Valentin gives as the result of his experiments upon seven males between 17-i- and 33 years of age, that the quantity of air expired in ordinary up to a somewhat quickened respiration, ranges between 239*3 and 1567*7 cubic centimetres (14*603 and 95*672 English cubic inches), the average of which was 655*11 c. c. (40*081 English cubic inches)4 Vierordt \u00a7, in repeated experiments upon himself, ascertained that at each expiration, when in a state of rest, he expelled from the lungs on an average 507 cubic centimetres (30*940 English cubic inches), and that the average of the five highest values was 699 c. c. (42*657 E. c. inches), and of the lowest 177 c. c. (10*801 E. c. inches). || Bourgery, from experiments upon\n* Wagner\u2019s Handw\u00f6rterbuch der Physiologie, band ii. s. 836.\nf Meckel\u2019s Archiv f\u00fcr Anatomie und Physiologie, band xiii. S. 83.\t1828.\nJ Lehrbuch der Physiologie,! band i. S. 538. These calculations of Valentin rest on the supposition that the expired air is fully saturated with moisture \u2014 a supposition invalidated by the experiments of Moleschott.\n\u00a7 Wagner\u2019s Handw\u00f6rterbuch der Physiologie, band ii. S. 835. Vierordt elsewhere states that he is of the middle height, and has no particularly roomy chest, was 59 kilogrammes in weight and 25 years of age when he performed his experiments.\nII The following estimates have been drawn from a limited number of experiments upon a single individual, or upon a very small number of in-\nz 2","page":339},{"file":"p0340.txt","language":"en","ocr_en":"340\nRESPIRATION.\nfifty males and twenty females*, with the view of ascertaining the relation between the intimate anatomical structure of the lungs, and the functional capacity of these organs in the two sexes, concludes that the volume of air required by an individual in ordinary respiration augments gradually with the age, being least in youth (from 5 to 15 years), in consequence of the extreme vascularity of the lungs ; increased from 15 to 30 years of age, in consequence of the proportional diminution in the closeness of the pulmonary capillary network of blood vessels ; and to a much greater amount in old age, in consequence of the more rapid diminution of the extent of the respiratory membrane, which begins to take place after the lungs have arrived at their full development, or the age of 30.\nIt is obvious that we are not yet in possession of data to enable us to venture upon an estimate of the average quantity of air inspired and expired at an ordinary respiration, when the body is at rest and the mind undisturbed, at different periods of life, in the two sexes, and in different physical configurations of body. It is equally apparent that this is liable to considerable variation, and that the different results obtained by most experimenters,\u2014 setting aside those where an obviously faulty method was pursued, \u2014 depends as much upon the inherent differences in the extent of the respiratory movements in the individuals experimented upon, as upon errors in the mode of experimenting, and that the chief error committed by some of them consists in deducing averages from the few and insufficient experiments performed by themselves, and casting doubts upon the results obtained by others, simply because\ndividuals, and are therefore of little value in enabling us to ascertain the average quantity of air taken into the lungs and again expelled in ordinary respiration. Besides, some of these experiments are liable to obvious objections. Borelli (De Motu Animalium, Pars Secunda, p. 118. ^/ugdani, 1685) who appears to have been the first who attempted to ascertain this by experiment, estimates it at 15 cubic inches. Turin (Diss. p. 41, 42, as quoted by Haller), from experiments on his own person, at 40 cubic inches ; and this is the estimate also formed by Menzies (op, cit. p. 28,) from his experiments. Goodwyn (The Connexion of Life with Respiration, &c., p. 36. 1788), from experiments on three individuals, estimates the quantity inspired at 12 cubic inches, which he supposes to be increased to 14 in the lungs by the increase of temperature. Sir H. Davy (Researches Chemical and Philosophical, &c., p. 433, 1800) informs us that he threw out of his lungs at each ordinary inspiration nearly 13 cubic inches; Mr. Abernethy (Surgical and Physiological Essays, Part II. p. 142, 1793), that he inspired 12 cubic inches; Dalton (Memoirs of the Literary and Philosophical Society of Manchester, 2nd Series, vol. ii. p. 26), also from experiments on his own person, estimates an ordinary inspiration at 30 cubic inches ; Allen and Pepys (London Phil. Trans, for 1808), from experiments on one individual, at 16^ cubic inches ; and Thomson (Animal Chemistry, p. 612. 1843) estimates his own inspirations at \"16 cubic inches.\n* Archiv. G\u00e9n\u00e9ral, de M\u00e9d. 4e S\u00e9rie, torn. i. p. 375, 1843, and Comptes Rendus, 23 Janvier, p. 182. 1843.\nthey do not accord with their own. It also necessarily follows that we are not in a position to form an estimate of the average quantity of air which passes out and in from the lungs in twenty-four hours in ordinary respiration. Vierordt*, from experiments on his own person, calculates that he respires 6034 cub. cent. (368*074 English c. inches) of atmospheric air in one minute, or 8,688,960 cub. cent. (530,026*560 Eng. c. in.) in the twenty-four hours. As, however, the respiration is rendered more energetic by speaking, walking, &c., any estimate drawn, as this by Vierordt is, from observations made when the body was in a state of rest, will be, as he was aware, too low ; and proceeding on some of the results of Scharling\u2019s experiments, he makes allowances for this increase, and estimates the quantity of air respired in the twenty-four hours at 624,087*401 English cubic inches. Valentin^ calculates that in his own person, after making allowances for temperature and watery vapour, he respires 469*9755 litres (28681 1948 English cubic inches) in an hour, and 688,348*6761 Eng. cubic inches, or nearly 398| cubic feet of atmospheric air in the twenty-four hours.J\nThe quantity of air drawn into the lungs during quickened or forced inspiration, and again expelled during expiration, also varies very considerably in different individuals of the same age. Sir H. Davy\u00a7, in many experiments upon himself, ascertained that at a temperature from 58\u00b0 to 62\u00b0 Fahr, he threw out of his lungs by a full forced expiration,\nCubic Inches.\nAfter a full voluntary inspiration,\nfrom........................... 189 to 191\nAfter a natural inspiration, from 78 \u2014 79\nAfter a natural expiration, from 67 \u2014 68\nSo that, making corrections for temperature, he calculates that his lungs, in a state of voluntary or forced inspiration, contained about 254 cubic inches ; in a state of natural in-\n* Op. cit. pp. 856, 857.\nt Op. cit. p. 570. The effects of exercise, digestion, Sec., are included in this estimate.\nX Mr. Coathupe (London and Edinburgh Phil. Magaz. vol. xiv. p. 401, 1839), from experiments on his own person in a state of rest, estimates the number of respirations at 20 in the minute, the average bulk of each respiration at 16 cubic inches, and the quantity of air that passes through the lungs in 24 hours, at 460,800 cubic inches, or 266*66 cubic feet. Mr. Coathupe\u2019s estimate agrees pretty closely with that of Dumas (Statique Chimique des Etres Organis\u00e9s, 3e edit. p. 87), also formed from experiments on his own person, in a state of rest.\nThe estimate of the quantity of air that passes through the lungs, given by Bostock (System of Physiology, p. 321, 1836) is in all probability above the average. He proceeds on the supposition that in ordinary respiration a man respires 40 cubic inches of air 20 times in a minute, so that he makes the quantity respired in the 24 hours, 1,152,000 cubic inches or about 666| cubic feet. It is probable that between 25 and 30 cubic inches of air for each ordinary inspiration will be found to be near the average in an adult male when in a state of rest.\n\u00a7 Researches Chemical and Philosophical, Sec., p. 410. 1800.","page":340},{"file":"p0341.txt","language":"en","ocr_en":"RESPIRATION.\n341\nspiration about 135 ; in a state of natural expiration about 118 ; and in a state of forced expiration 41 .* * * \u00a7 Goodwynj-, in his experiments on the capacity of the lungs upon four individuals after a natural death, found the residual air in the lungs to vary from 90 to 125 cubic inches, giving an average of 109, and as the chest, after a natural death, may be regarded as in a state of natural or ordinary expiration, this result differs very little from that of Davy. Allen and PepysJ, in one experiment on the capacity of the lungs in a middle-sized man after death, also obtained a little more than 100 cubic inches of residual air. Vierordt\u00ff supposes that the residual air in the lungs, after the deepest expiration, is about 600 cub. cent. (36*600 Eng. cub. in.), which differs but little from the estimate of Davy.\nHerbst || made experiments upon 11 males, between 16 and 30 years of age, with the view of ascertaining the quantity of air drawn into the lungs in forced inspiration. The smallest quantity observed was in a Jew aged 22, of small stature, and feeble muscular system. He inspired between 60 and 70 Parisian cubic inches (between 72*635 and 84*738 Eng. cub. in.) after an ordinary expiration ; between 102 and 118 (123*476 and 142*844 Eng. cub. in.) after a strong expiration ; and 120 (145*266 Eng. cub. in.) after the strongest expiration. The largest quantity inspired was by a young man of 25 years, of middle height with a broad chest and large and powerful muscles, who inspired by a forced inspiration, about 169A- English cubic inches, without any previous voluntary expiration; about 290i after a strong expiration ; and about 290\u00a3 or 295\u00a3 after the strongest expiration. A young man of 23 years of age, 6 feet high, with broad chest and large muscles, inspired, without any previous voluntary expiration, 121 English cubic inches, and 280*72 after the fullest expiration. The quantities of air drawn into the lungs in forced inspiration in the other eight males, were intermediate between the highest and lowest mentioned above, and the average was about 202 English cubic inches.^- Herbst also satisfied himself that the lungs of females have a considerably smaller capacity for air than those of males. He states that robust females, about the age of 30, may inspire without a previous voluntary expiration, 72^ English cubic inches, after an ordinary ex-\n* Sir H. Davy states that this capacity is most probably below the medium, as bis chest was narrow.\nf Op. cit. p. 26.\nt Philos. Trans, of London, 1809.\n\u00a7 Op. cit. p. 892.\n|| Op. cit. p. 98.\nHerbst found that a hoy of 15 years 'inspired 116*16 English cubic inches after a strong expiration, and expired the same quantity after a full inspiration. Another boy of 13 years, but of the size of one of 15, likewise expired 116*16, while a boy of 11 years inspired without a previous expiration, 36*30 ; after a strong expiration he inspired 72*60 English cubic inches, and expired the same quantity after a full inspiration.\npiration nearly 109, and after the strongest expiration, from about 157\u00a3 to 174\u00a3 English cubic inches.* Herbst had an opportunity, in two of these experiments on males, of ascertaining the effects of tight clothing on the extent of the respiratory movements. One individual who inspired 128 and another 116*16 English cubic inches, without a previous expiration after the clothes were loosened, could before this only inspire 96*80 and 60J- English cubic inches. + The most extensive experiments by far, made with the view of ascertaining the quantity of air which can be thrown out of the lungs by forced expiration, after the deepest inspiration, are those of Mr. Hutchinson. $ These experiments were performed upon 1923 males, and they were made to breathe into an instrument constructed for the purpose, and which he has called a spirometer. He has inferred from the data he has collected on this point, the rule, that \u201c for every inch of height (from 5 feet to 6) 8 additional cubic inches of air at 60\u00b0 Fahr, are given out by a forced expiration ; \u201d so that he believes that from the height alone of an adult male, he can tell what quantity of air he should breathe to constitute him healthy, and that this method may be turned to important practical application in ascertaining disease of the lungs,\n* Bourgery (op. cit.) states, that in well formed and healthy individuals, a man at 30 will, by a forced inspiration, draw into the lungs 2*50 to 4*30 litres (or 152*567 to 262*416 English cubic inches), and a woman from 1*10 to 2*20 litres (or 67*129 to 134*259 English cubic inches), and has inferred from his experiments, that at the same age the amount of forced respiration of the male doubles that of the female, and this conclusion accords with the results of Mr. Thackrah (The Effects of Arts, Trades, and Professions, &c., on Health and Longevity, 2nd edit. p. 181, 1832), who states that \u201c extensive examination shows us that, while healthy men exhale by the pulmometer 200 cubic inches and upwards, women rarely exceed 100, and often do not reach that amount.\u201d Mr. Thackrah supposes that this difference is due, to a considerable extent, to tight lacing by females.\nf The condition of the stomach as to fulness, also affects the extent of the respiratory muscular movements. Mr. Hutchinson says, \u201c I have found a dinner diminish the vital capacity (by which he means the greatest voluntary expiration following the deepest inspiration) to the extent of 12 and even 20 cubic inches.\u201d The position of the body has also, according to Mr. Hutchinson (opus cit. p. 197), a considerable effect upon the vital capacity of the chest. In experiments upon himself he found that when standing he could throw out 260 cubic inches ; sitting, 255 ; and when recumbent (supine), 230, (prone) 220, so that position effected a difference of 40 cubic inches. In a fit of dyspnoea a person can breathe easier in the erect or sitting than in the recumbent posture, as the dorsal movements that attend difficult respiration, are freer in the former than in the latter position.\nJ Journal of the Statistical Society of London, vol. vii. 1844, and Medico-Chirurgical Transactions of London, vol. xxix. p. 137. 1846. The memoir in the last publication contains a more extensive series of experiments than that in the former. These researches would require to be still farther extended upon both sexes at the various periods of life, and under varied circumstances, before they can yield all the information on this subject that is desirable.\nz 3","page":341},{"file":"p0342.txt","language":"en","ocr_en":"RESPIRATION.\n342\nunder circumstances where the ordinary methods fail. Mr. Hutchinson has given the following table to show the quantity of air expelled by the strongest expiration after the deepest inspiration for every inch of height between 5 and 6 feet, as ascertained by actual experiment (column 1) by his spirometer, and as calculated according to the rule mentioned above (column 2).\nHeight.\tFrom Observation.\tRegular Progression.\nft. in. ft. in.\tcub. in.\tcub. in.\n5 0 to 5 1\t174\t174\n5 1 \u2014 52\t177\t182\n5 2 \u2014 53\t189\t190\n5 3 \u2014 54\t193\t198\n5 4 \u2014 55\t201\t206\n5 5 \u2014 56\t214\t214\n5 6 \u2014 57\t229\t222\n5 7 \u2014 58\t228\t230\n5 8 \u2014 59\t237\t238\n5 9 \u2014 5 10\t246\t246\n5 10 \u2014 5 11\t247\t254\n5 11 \u2014 6 0\t259\t262*\nMr. Hutchinson has found that two other conditions of the body besides the height, regulate the quantity of air that passes to and from the lungs in forced voluntary respiration, and these are age and weight. He states that weight does not affect the respiratory power of an individual of any height between 5 feet 1 inch and 5 feet 11 inches until it has increased 7 per cent, above the average weight of the body in persons of that height, but beyond this it diminishes in the relation of 1 cubic inch per pound for the next 35 pounds\u2014the limit of the calculation. In males of the same height the respiratory power is increased from 15 up to 35 years of age, but from 35 to 65 years it decreases nearly li cubic inch for each year .-J- Bourgery\n* Med.-Chir. Trans, vol. xxix. p. 237. Experiments to ascertain the quantity of air that may be inspired or expired in forced respiration have also been performed by Hales (Statical Essays, vol. i. p. 243), Jurin, Menzies, Goodwyn, Dr. Bostock (System of Physiology, p. 316. 1836), Dalton (Opus cit. p. 26), Thomson (Animal Chemistry, p. 610. 1843), Valentin (Opus cit. p. 540), and Thackrah (The Effects of Arts, Trades, and Professions, &c. on Health and Longevity, 2nd edit. pp. 27, 30, 64, 76, 98,181, and 182). These experiments, however, are neither sufficiently numerous\u2014several of them having been performed on a single individual only,\u2014 nor are they accompanied with the details necessary to enable us to contrast them with those of Mr. Hutchinson ; but the results obtained in the greater number of these do not differ much from those of Mr. Hutchinson upon men of middle stature. Valentin experimented on six males, and his estimates rest on the questionable supposition that the expired air is frilly saturated with moisture. Thomson experimented on 11 males and 1 female, from 14 to 33 years of age ; and Mr. Thackrah\u2019s experiments were considerably more extensive, and were made on individuals of different trades and professions.\n\u25a0f Mr. Hutchinson has not observed any direct relation between the circumference of the chest and the respiratory power or what he terms the vital capacity. According to the experiments of Herbst\nconcludes from his experiments already referred to, that the measure of respiration (by which he apparently means the quantity of air which may be drawn into the lungs by a forced inspiration) is greater the younger and thinner the person is ; that its maximum in both sexes occurs at the age of 30 ; that the relation of a forced and ordinary respiration diminishes with the age of the individual, being, he says, from 1 to 12 at three years of age, as 1 to 10 at fifteen, as 1 to 9 at twenty, as 1 to 3 at sixty, and as 1 to a or -\u00a7\u25a0 at eighty years ; whence it follows that in youth there is an immense respiratory power in reserve for any violent exertion, while in old age the individual under such circumstances is at once out of breath.* *\nChanges upon the atmospheric air in respiration,\u2014 One of the most obvious changes, under ordinary circumstances, upon the air that enters the lungs in respiration is an increase of its temperature, and consequently an augmentation of its bulk. As a quantity of water is readily supplied by the fluid secretions of the inner surface of the air-passages, and by the blood in the pulmonary capillary blood-vessels, this augmentation of the temperature of the air is also necessarily attended by an increase of its watery vapour, and consequently by an additional increase in its bulk and elasticity. The expired air, therefore, contains more caloric, more watery vapour, is more elastic, and is of less specific gravity than the inspired air. Valentin performed 12 experiments on his own person by breathing through an apparatus invented by Brunner and himself, to ascertain the temperature of the expired air, and he obtained the following results. In breathing atmospheric air of a temperature varying from 8\u00b0-5 to 330,5 Reaumur (510,125 to 107\u00b0-375 Fah.), he observed a difference of 1\u00b0*75 R. (3\u00b0*937 F.) in the temperature of the expired air. While breathing in the lowest temperature, viz. 51\u00b0*125 F., the temperature'of the expired air was 96\u00b0* 687 F., and was warmer than the inspired air by 45\u00b0*562 F. ; and when breathing in the highest temperature the expired was colder\n(Opus cit. p. 104), and Mr. Hutchinson, the mode of determining the quantity of air which the lungs are capable of containing during life in any particular case, by measuring after death the quantity of air which can be thrown into them by inflation, is fallacious. This is probably chiefly due to the congestion of the depending parts of the lungs by blood, so frequently found after death. Both Herbst and Mr. Hutchinson have performed experiments to show the extent to which the quantity of air in forced respiration is diminished in phthisis.\n* Among the proofs of these conclusions, advanced by Bourgery, it is stated by him that the measure of respiration of a hoy of 15 years of age is 2 litres (122-054 Eng. cubic inches), and a man of 80 years 1-35 litre (82*386 Eng. cubic inches) : that while a boy of 10 years and a man of 80 inspire by a forced inspiration the same quantity of air, viz. 1-35 litre, yet the ordinary respiration of the former is only 1 decilitre (6*102 Eng. cub. in.), while that of the latter is 9 decilitres (54*918 Eng. cub. in.) ; so that with a mass three times smaller, the child possesses an energy of hematose eight times greater.","page":342},{"file":"p0343.txt","language":"en","ocr_en":"RESPIRATION.\nthan the inspired air by 6\u00b0* *75 F. In the last experiment, though the inspired air was 7\u00b0\u2019875 F. warmer than the internal temperature of the body, the expired air was only about 1\u00b0-125 F. warmer than what it is when air of the ordinary temperature is breathed. The average temperature of the expired air is, according to Valentin, 99\u00b0\u20185 F. when breathing in an atmosphere of moderate temperature.* According to his calculations, when a person breathes 100 cubic centimeters of atmospheric air at the temperature of 60\u00b0 F., their bulk is increased to 107-87975 cubic centimeters when raised to the temperature of 99*5 F. in the lungs, since the expansive co-efficient of atmospheric air is 0-3665. As the expired air, however, contains 4*4 per cent, of carbonic acid gas, and as the expansive co-efficient of this last gas is 0*369087 the expansion of the expired air will differ slightly from what it would be were it composed of oxygen and nitrogen only, and will be 107-882197 cubic centimeters.f\nIt is difficult to obtain an accurate estimate of the quantity of watery vapour that escapes from the body along with the expired air. Were the inspired and expired air always fully saturated with moisture, and were their quantities, barometric pressure, and relative temperature accurately ascertained, the absolute and relative quantities of watery vapour which they contain could be calculated by certain algebraic formulae. The atmospheric air which we breathe is sometimes saturated with moisture, more frequently the dew-point, or that at which the precipitation of the atmospheric moisture can occur, is considerably below the temperature of the air, and the number of thermometric degrees between the actual temperature of the air and the dewpoint shows the degree of dryness in the air, or in other words how much it is below the point of saturation with moisture. J The\n* Moleschott (Holl\u00e4ndische Beitr\u00e4ge zu den anatomischen und physiologischen Wissenschaften, band i. heft i. S. 86. Utrecht und D\u00fcsseldorf, 1846) has more lately made experiments on the temperature of the air in the back part of the mouth, and ascertained that in a range of temperature in the external air to the extent of 12\u00b0-6 F. that there was scarcely any difference in the temperature of the expired air. In 26 experiments,\u2014 three of which were upon women, \u2014 upon individuals chiefly from 19 to 43 years of age, he found the average temperature of the expired air to be nearly 980,6 F. The longer or shorter time which the inspired air remains in the lungs will modify the results in such experiments.\nf Opus cit.\nX According to the calculations made by the late Professor Daniell (Elements of Meteorology, vol. ii. p. 316. London, 1845) from meteorological tables, kept for 17 years consecutively, the mean temperature of London is 490,54 F., while the mean dewpoint is 44\u00b0-31, giving 50-59 upon the thermometric scale, and 827 upon the hygrom\u00e9trie scale, as the degree of dryness. The mean elastic force of this watery vapour is, he says, *342 of an inch of mercury, and a cubic foot contains 3'806 grains of moisture. The greatest degree of dryness was 49\u00b0 F., or the least degree of moisture when the hygrom\u00e9trie scale was 235. According to Dalton\u2019s observations (Manchester Memoirs, 2nd series, vol. ii.) the medium of\nloss of watery vapour by the lungs will evidently be regulated by the temperature of the inspired air, the quantity of watery vapour it holds in solution, the volume of air inspired, and the length of time it remains in the lungs. The lower the temperature of the inspired air, the less it approaches to the point of saturation with moisture, and the greater its volume, the greater will be the loss of watery vapour by the lungs. When the respirations are more rapid, and the sojourn of the air within the lungs is short, the same volume of expired air will probably contain less water in solution, than when its sojourn there is more prolonged, but the more frequent renewal of the air within the lungs will be more than sufficient to compensate for this.\nThe most correct and trust-worthy experiments to ascertain by the direct method the quantity of watery vapour in the expired air are those of Valentin and Brunner.* These experiments were performed upon seven males between the ages of 17* and 33 years, and the maximum of watery vapour exhaled was 13156*323 Troy grains in the 24 hours; the minimum 451D374 grains, and the average 7819*222 grains. The quantity of watery vapour in the expired air within a given time varied in the same individual ; and in one experiment it was increased after drinking. In these experiments the entire quantity of water in the expired air was ascertained, so that the actual quantity given, off by the fluids of the body must have been less than this ; and Valentin calculates that if a person breathes atmospheric air saturated with moisture, at the temperature of 60\u00b0 Fahr., and if the expired air be at the temperature of 99\u00b0-5 Fahr., and also saturated with moisture, about \u25a0\u00a7 of the watery vapour contained in the expired air will be furnished by the fluids of the body.f We have seen that\naqueous vapour in this climate (that of Manchester) may he estimated at -30 of an inch of mercury due to the temperature of 44\u00b0 F. This vapour, he says, is increased by the temperature of 98\u00b0 in the lungs from -30 to 1-74 inch of mercury, being an increase of 1-44 inch; but it will only be equal in weight to air of 1 inch of force, as the specific gravity of vapour is less than that of air in the proportion of 7 to 10. Valentin calculates (Opus cit. p. 533) that 100 cubic centimeters of dry air under a barometric pressure of 29-922 English inches, raised to the temperature of 99'5 F., and saturated with moisture, would be expanded to 106-488 cubio centimetres.\n* Opus cit. p. 536. Lavoisier has given different estimates of the quantity of watery vapour in the expired air in his papers on respiration and transpiration in the M\u00e9moires de l\u2019Academie des Sciences. Hales, Menzies, and Abernethy, from experiments on themselves, and employing different kinds of apparatus, all more or less imperfectly suited for the purpose, have respectively estimated it at 9792 grs. or about 20 oz., 2880 grs. or about 6 oz., 4320 grs. or about 9 oz. Dalton and Thomson, from calculations based upon the relative quantities of watery vapour required to saturate the inspired and expired air, have estimated it respectively at 1-55 or nearly l^lb. Troy or 8640 grs., and at 19 oz.\nt Opus cit. p. 533. Vierordt (Physiologie des Ath-mens, &c. S. 155. 1845) calculates from the quantity\nz 4","page":343},{"file":"p0344.txt","language":"en","ocr_en":"344\nRESPIRATION.\nseveral of the calculations of the amount of the watery vapour exhaled from the lungs proceed on the supposition that the expired air is saturated with moisture, but this has not been substantiated by the only experiments made with the view of determining this point. In Moleschott\u2019s experiments, the amount of water held in solution varied. In five out of seven experiments the watery vapour in the expired air was appreciably less than what is sufficient to saturate air of the same temperature, while in one experiment it was saturated. On taking the average difference in the seven experiments performed, as much as possible under similar circumstances, between the actual quantity of moisture in the expired air, and in air of the same temperature saturated with moisture, he found that 2420 cub. cent, (147-620 Eng. cub. inches) of the expired air would require a quantity of watery vapour additional to that already existing in it equal to 10 millegrammes (\u2018150 Eng. Troy grains) to saturate it. From these experiments he concludes \u201cthat in the greater number of instances the expired air in man is not saturated with watery vapour, but sometimes such a saturation occurs.\u201d* * * * \u00a7 Magendie observed, in experiments on dogs, that the escape of an increased quantity of watery vapour from the mouth follows the injection of water into the veins, caused, as he supposes, by the transpiration from the lungs being considerably increased.f\nAnimal matters in quantities too minute to be subjected to analysis are also exhaled from the lungs, and escape along with the expired vapour. The condensed vapour from the lungs, when collected in a vessel, and kept for some days, putrefies, and emits an ammoniacal smell. % We are also often sensible of the escape of different substances, previously taken into the stomach, along with the expired air, by their smell ; and the experiments of Nysten \u00a7,\nof air respired by himself in a state of rest, supposing the temperature of the expired air to be 98\u00b0-6Fahr., and saturated with moisture, the temperature of the inspired air to he 57\u00b0\u20182 F., and containing only its average quantity of moisture, that the quantity of water in the expired air will amount in the 24 hours to 5555-880 Troy grains, of which, on an average, 4953-993 grains may be allowed for the loss of water from the inner surface of the lungs and air passages, and 601-887 grains for the quantity previously contained in the inspired air. As, however, the body is not at rest during a considerable part of the 24 hours, the loss of watery , vapour must be greater than this.\n* Holl\u00e4ndische Beitr\u00e4ge zu den anatomischen und physiologischen Wissenschaften, band i. 'S. 96. 1846.\nf Compendium of Physiology, translated by Milligan, p. 395. 1831.\nJ Valentin and Brunner (Opus cit. pp. 571, 572), in their experiments on the human species, detected the presence of a minute quantity of organic matter in the expired air. This was ascertained by the sulphuric acid, through which the expired air was made to pass, becoming red. Marchand (Journal f\u00fcr praktische Chemie, von Erdman und Marchand, band xxxiii. S. 129. 1844), in his experiments on frogs, also observed this.\n\u00a7 Recherches de Physiologie, &c. p. 145.\nMagendie*, Tiedemannf, and others, prove that various organic and mineral substances, when injected into the veins, escape in part by exhalation from the lungs.\nIf the inspired air, during its sojourn in the lungs, becomes increased in bulk from an increase in temperature and an addition of watery vapour, it suffers a small diminution from the absorption of part of its constituent gases. The older experimenters observed a diminution in the air respired, but as they experimented with imperfect apparatus, and transmitted the expired air through water which would absorb part of the carbonic acid gas, little confidence is to be placed in their results.J There can be no doubt that a greater amount of oxygen disappears from the inspired air than what is sufficient for the formation of the quantity of carbonic acid gas in the expired air, and that there is a slight diminution in the bulk of the expired air from this cause ; but we cannot speak so decidedly regarding any changes in the quantity of the nitrogen. Proven\u00e7al and Hum-boldt\u00a7, in their experiments on the respiration of fishes, and Spallanzani |J, in his experiments on snails, observed an absorption of azote : while JurineH and Nysten**, in their \u25a0experiments on the human species, and Ber-tholletff, DespretzJJ, Dulong\u00a7\u00a7, and Mar-tigny || ||, in their experiments on warm-blooded animals,and TreviranusIMI in his experiments on the cold-blooded animals, observed an exhalation of azote. Dr. W. F. Edwards * * *, in\n* Opus cit.\nf Zeitschrift f\u00fcr Physiologie, band v. 1835. This paper is translated in the British and Foreign Quarterly Review, vol. i. p. 241. Tiedemann, in this paper, has given an account of all the experiments previously performed on this point by others.\nJ Goodwyn (Opus cit. p. 51), Plaff (Nicholson\u2019s Journal of Natural Philosophy, vol. xii. p. 249. 1805), Dr. Alex. Henderson (Nicholson\u2019s Journal, vol. viii. p. 40), and Sir H. Davy (opus cit.), in their experiments on the human species, observed a diminution in variable proportions in the respired air ; and Henderson, Plaff, and Davy, supposed that part of this diminution was caused by the absorption of nitrogen at the lungs.\n\u00a7 M\u00e9m. de la Soci\u00e9t\u00e9 d\u2019Arcueil, [tom. ii. p. 388. 1809.\n|| M\u00e9moire sur la Respiration, traduit par Sene-bier, pp. 162, 184, and 230. 1803. An absorption of azote was not uniformly observed by Spallanzani.\nM\u00e9moire couronn\u00e9 en 1787, par la Soci\u00e9t\u00e9 Royale de M\u00e9decine, as quoted by Nysten.\n** Opus cit. p. 186.\nff M\u00e9m. de la Soci\u00e9t\u00e9 d\u2019Arcueil, tom. ii. p. 459.\nj j Annales' de Chimie et de Physique, tom. xxvi. p. 337. 1824,'\n\u00a7\u00a7 Magendie\u2019s Journal de Physiologie, \"tom. iii. p. 45. 1823.\nIl II Magendie\u2019s Journal, tom. x. p. 337. 1824.\nIf Zeitschrift f\u00fcr Physiologie, band iv. Trevi-ranus says, \u201c in some of my experiments there was more azote than carbonic acid exhaled, and this not only in the avertebrata, but also in the frog.\u201d p. 33.\n*** De l\u2019Influence des Agens Physiques sur la Vie, p. 420. Tableaux 63,64, and 65. 1824. Dr. Edwards concludes from his experiments that there is both a constant exhalation and absorption of azote at the lungs, and that these two actions are sometimes equal, while at other times the one preponderates over the other.","page":344},{"file":"p0345.txt","language":"en","ocr_en":"RESPIRATION.\n345\nhis experiments upon warm-blooded animals and reptiles, found that in some cases the quantity of azote in the air respired was increased, in others diminished, while in others it remained unchanged ; but these changes in the quantity of azote did not equal the difference between the amount of oxygen absorbed and of carbonic acid exhaled. Lavoisier and Seguin*, Allen and Pepysf, Valentin and Brunner J, and Dr. Thomson\u00a7, in their experiments on the respiration in the human species, detected no change upon the quantity of azote.j| BoussingaultH, by a series of comparative analyses of the aliments consumed, and of the excrements in a turtledove, arrived at the conclusion by this indirect method of research that azote was exhaled.\nMarchand**,in his carefully-conducted experiments on frogs, detected a quantity of ammonia in the tube of his apparatus, containing the concentrated sulphuric acid, and concludes that nitrogen in this combination is exhaled from the lungs and skin.\nFrom a review of all the experiments upon the nitrogen of the respired air, we perceive that though the evidence preponderates in favour of the exhalation of a small quantity of nitrogen from the lungs ff, yet that it is not sufficiently conclusive to justify us in stating that its operation is constant. It appears,\n* M\u00e9m. de l\u2019Acad\u00e9mie Royale for 1789, p. 574.\nf Opus cit.\nt Opus cit.\n\u00a7 Animal Chemistry, p. 612. 1843. Dr. Thomson says, in experimenting upon animals placed in vessels in which the air was renewed during the experiment, no diminution of the volume of air took place, but the case was very different when the animal was obliged to breath confined air. Nysten (Opus cit. p. 230) observed an evolution of azote in the human species, both in a state of health and disease, when the same air was breathed several times. Marchand, on the other hand (Journal f\u00fcr praktische Chemie, band xxxiii. S. 166), from his experiments on frogs placed in close vessels, concludes that it is exceedingly probable, if not certain, that, under this condition, these animals absorb part of the azote of the atmospheric air.\n|| Vierordt remarks upon Valentin and Brunner\u2019s experiments, and the same observation applies to to the others on the human species, that the evolution of a minute quantity of nitrogen, not readily detected during the short time each of these experiments was carried on, might amount to a notable quantity in the 24 hours.\nAnnales de Chimie et de Physique, torn. xi. p. 433. 1844. In taking the mean of the result of his experiments, he found a turtle-dove, weighing 2885-971 English Troy grains, evolved in 24 hours from the lungs 288-597 grains of carbonic acid gas, and 2-469 grs. of azote, or in volume 576-155 English cubic inches of carbonic acid and 7-689 cubic inches of azote,\u2014a considerably smaller quantity than was obtained by Dulong and Despretz in their experiments by the direct method. This quantity of azote, according to Boussingault, constitutes the one-third of the whole of this substance which entered into the composition of the aliment of the pigeon.\n** Opus cit.\nff It must, however, he remembered that in the great majority and in the most trust-worthy of these experiments in favour of the increase of the nitrogen, the exhalations from the skin were mixed with those from the lungs.\nhowever, from the evidence adduced, that the nitrogen in the expired air is at least frequently increased in quantity in ordinary respiration, but not to the extent of affecting materially the percentage of this gas in the respired air.* Valentin and Brunner, in their carefully conducted experiments, could detect no traces of hydrogen, carbonic oxide, or carburetted hydrogen, in the expired air.\nBy far the most important chemical change the atmospheric air undergoes during its sojourn in the lungs, is a diminution in the quantity of its oxygen and an increase of its carbonic acid gas ; and it may be safely affirmed that all the other changes in the respired air are of trivial importance in the function of respiration, when compared with this. There can be no doubt that the conclusion drawn by Allen and Pepys from their experiments, that the amount of oxygen which disappears from the inspired air is exactly equal to the quantity required to form the carbonic acid that appears in the expired air, is incorrect ; for all the latest and most accurate experiments have confirmed the general accuracy of the results obtained by Lavoisier and Davy on this point, and have satisfactorily determined that a larger quantity of oxygen disappears from the inspired air than what is sufficient to form the carbonic acid gas present in the expired air.\nPercentage and absolute quantity of carbonic acid gas in the expired air. \u2014 The results of the earlier experimenters on this point are of so little value that we need not refer to them. The following results have been obtained by some of the later experimenters : \u2014\nQUANTITY OF CARBONIC ACID GAS IN THE 100 PARTS\nOF THE EXPIRED AIR ESTIMATED BY VOLUME.\nProut Coathupe Brunner & | Valentin J Vierordt Thomson\nAverage.\tMax.\tMin.\tDifference between Maximum and Minimum.\n3-45\t4-10\t3-30\t\u202280 f\n4-02\t7-98\t1-91\t6-07 %\n4-380\t5-495\t3-299\t2-196 \u00a7\n4-334\t6-220\t3-358\t2-86 ||\n4-16\t7-16\t1-71\t5-45 f\n* Even supposing the nitrogen of the respired air to remain unaltered in quantity, yet as the quantity of oxygen absorbed is somewhat greater than what is necessary to forai the carbonic acid exhaled along with the expired air, the percentage of the nitrogen in the inspired air will be slightly greater than in the expired air when estimated by volume.\nf Thomson\u2019s Annals of Philosophy, vol. ii. p. 333. 1813. In some subsequent experiments by Prout (same work, vol. iv. p. 331) the range in the quantity of carbonic acid gas in the expired air was between 2-80 and 4-70, the minimum number occurring once only, and while he was sleepy. Prout\u2019s experiments were performed upon himself, and at every hour of the day and night.\nt London, Edinburgh, and Dublin Philosophical Magazine, vol. xiv. p. 401. 1839. These experi-","page":345},{"file":"p0346.txt","language":"en","ocr_en":"346\tRESPIRATION.\nThe results obtained by Brunner and Valentin, and by Vierordt, appear especially trustworthy ; and though the number of experiments is too small to enable us to deduce averages with any confidence, yet we may in the meantime consider that, in an adult male of middle age, the average quantity of carbonic acid in the expired air is about 4* *35 per cent.* The quantity of carbonic acid gas in the expired air is not uniform in the same individual, but varies repeatedly, even in the course of the twenty-four hours, and these variations are determined by certain conditions of the body and of the surrounding media.\nPeriod of the day. \u2014 Dr. Prout believed that he had discovered that the quantity of carbonic acid formed during respiration is always greater at one and the same period of the day than at any other ; that this maximum occurs between 10 a. m. and 2 p. m., or generally between 11 a. m. and 1 p. m. ; and that the minimum commences about 8h 30' P. m., and continues nearly uniform till about 3h 30' A. m. The beginning and end of the period of minimum evolution of carbonic acid he believed to be connected with the beginning and end of twilight, and he adduces some experiments in favour of this opinion. In these experiments Prout attended only to the percentage of the carbonic acid in the expired air, and took no means to ascertain the volume of air passing through the lungs at the time,\u2014 an omission which seriously diminishes their value.f Prout\u2019s results do not accord with the previous experiments of Brande J, nor\nments were 124 in number, and performed upon himself at almost every hour of the day between 8 a. m. and midnight. The difference between the maximum and minimum percentage is great in Coathupe\u2019s experiments ; but this was only found in single cases.\n\u00a7 Opus cit. p. 546. These experiments were 34 in number, and performed upon three adult males between 33 and 53 years of age.\n|| Article Respiration in Wagner\u2019s Handw\u00f6rterbuch, p. 853. Yierordt\u2019s experiments were performed upon himself, were nearly 600 in number, were continued over a period of nearly 15 months, and were chiefly made between 9 a. m. and 7 p. m. Yierordt, in his Physiologie des Athmens, has given in a tabular form the results obtained in 578 experiments, p. 21\u201465.\n! Animal Chemistry, p. 614. 1843. These experiments were made on 10 males and 2 females, and between 11 and 12 o\u2019clock A. m.\n* Dalton (Opus cit. p. 25), Dumas (Essai de Statique Chimique des Etres Organis\u00e9s, 3me edit., p. 87. 1844), and Gay Lussac (Annales de Chimie et de Physique, tom. xi. p. 14. 1844), estimate the average carbonic acid in the expired air at 4 per cent. Apjohn (Dublin Hospital Reports, vol. v. 1830), and Macgregor (Transactions of British Scientific Association for 1840, p. 87), estimate it at 3-6 and 3*5 per cent. The estimate of Allen and Pepys (Opus cit.), and Dr. Fyfe (Dissert. Chemico-Physiol. Inaug. de Copia Acidi Carbonici e Pulmo-nibus inter respirandum evoluti. Edinburgh, 1814), making the average quantity 8- to 8-5 per cent., is undoubtedly considerably too high ; and they were led into this error by the impediment to the free respiration occasioned by the imperfect apparatus employed.\nf Thomson\u2019s Annals of Philosophy, vols. u. and iv.\nI Nicholson\u2019s Journal, vol. xi. p. 82.\nwith the subsequent experiments of Coa-r thupe* and Vierordt. f It would appear, therefore, that the variations in the quantity of carbonic acid in the course of the day do not occur at uniform periods, independent of other circumstances, as Prout supposed. It is, however, proved by the experiments of Scharling % upon the human species, by Bous-singault \u00a7 upon the turtle dove, and by Marchand || upon frogs, that the absolute amount of carbonic acid exhaled is very considerably less during the night than during the day. Scharling gives in the following table the relative proportion of the carbon exhaled during the day and night in six individuals upon whom he experimented : \u2014\n\tNight.\tDay.\n1.\tScharling 2.\tThomson\t1\t1*237\n\t1\t1*235\n3. A Soldier\t1\t1*420\n4. An adult Female\t1\t1*240\n5. A Boy -\t-\t-\t1\t1*266\n6. A Girl -\t1\t1*225\nThe average proportion is 1 during the night to 1\u2019237 during the day, or, in other words, nearly a fourth part more carbonic acid gas is evolved during the day than during the night.! How much of the diminished evolution of carbonic acid during the night is dependent upon the languor and drowsiness incident to that period, and how much upon the absence of the sun\u2019s rays and other causes, it is at present impossible to determine. It appears that this diminished evolution of carbonic acid during the night does not require the occurrence of sleep, though no doubt it is increased by sleep.\nDigestion. \u2014 Seguin and Lavoisier **, in their experiments upon Seguin found that when he was in a state of repose and fasting he vitiated only 1210 cubic inches of oxygen gas in an hour, while, during digestion, this was raised to between 1800 and 1900 cubic\n* Opus cit.\n\u2022j* Physiologie des Athmens, Sec., S. 66.\nJ Annalen der Chemie und Pharmacie, band xlv. s. 214. 1843. Translated in Annales de Chimie et de Physique, tom. viii. p. 478. 1843.\n\u00a7 Annales de Chim. et de Phys., tom. xi. p. 445. 1844. Boussingault calculates from his experiments that, supposing the entire day to be divided into 12 hours of sleep, and 12 hours of waking, the quantity of carbon consumed in respiration by the turtle-dove during the day and night would be as follows : \u2014\nCarbon consumed in the day (English\nTroy grains per hour)............. 3*981\nCarbon consumed in the night (ditto) ..\t2*500\n|| Journal f\u00fcr praktische Chemie, von Erdman und Marchand, band xxxiii. S. 148.\t1844.\n! Annalen der Chemie und Pharmacie, band xlv. S. 236.\n** Memoire de l\u2019Acad\u00e9mie Royale for 1789, p. 574, 575. Jurine (Encyclop\u00e9die M\u00e9thodique, M\u00e9decine, article Air, tom. i. p. 497. 1787) has also maintained that a greater quantity of air is vitiated during digestion.","page":346},{"file":"p0347.txt","language":"en","ocr_en":"RESPIRATION.\t347\ninches. Spallanzani* * * \u00a7 ** * * observed that snails, after a redundant repast, exhaled considerably more carbonic acid gas than when fasting. Similar observations have been made upon insects by Sorgf and Newport upon the Mammalia by Zimmermann \u00a7, and upon the human species by Scharling [|, Valentin^, and Vierordt. The most complete experiments on this point are those of Vierordt, performed on himself, the results of which are contained in the following tables. His dinner lasted from 30 minutes past 12 to 1 o\u2019clock : \u2014\nHours.\tPulse per minute.\tRespirations per minute.\tVolume of an Expiration.\tExpired in one minute.\t\tPer centage of carbonic acid in the expired air.\n\t\t\t\tAir.\tCarbo- nic acid gas.\t\n\t\t\tIn English cubic inches.\t\t\t\n12 2\t66-5 82-3\t11-\t55 12-\t77\t31-\t43 32-\t26\t362-64 412-17\t15-77 18-22\t4-32 4-37\nDifference\t15-8\t1-221\t-83\t\t49-53\t2.45\t\u202205\nTo ascertain that this increase in the quantity of carbonic acid evolved from the lungs was really dependent upon digestion, and not upon any other cause, the experiment was repeated at the same period of the day when he had not dined, and had eaten nothing since his breakfast at 7 o\u2019clock, and the following results were obtained : \u2014\nHours.\tPulse per minute.\tRespirations per minute.\tVolume of an Expiration.\tExpired in one minute.\t\tPer centage of carbonic acid in the expired air.\n\t\t\t\tAir.\tCarbo- nic acid gas.\t\n\t\t\tIn English cubic inches.\t\t\t\n12\t63\t10\t33-25\t332-58\t16-49\t4-69\n1\t64\t9\t32-16\t289-44\t14-75\t5-09\n2\t62-5\tQ1 Jf2\t35-08\t334-35\t15-75\t4-73 **\n* M\u00e9moires sur la Respiration, p. 217\u2014223.\nf Disquisitio Physiologica circa Respirationem In-sectorum et Vermium. 1805.\nJ London Phil. Trans, for 1836 and 1837.\n\u00a7 The result of Zimmermann\u2019s experiments is given on Vierordt\u2019s authority in Wagner\u2019s Handw\u00f6rterbuch, band ii. S. 884.\n|| Opus cit. In Scharling\u2019s experiments the total quantity of carbonic acid exhaled from the body during a given time was determined, and they are, therefore,' not liable to the errors of those experiments where the percentage only was ascertained.\nOpus cit. p. 566. Valentin states that an hour after he had taken a meal of bread and butter, the quantity of carbonic acid given off by the lungs was raised from 616-085 to 627-505 English Troy grains per hour, while after a fast of 16 hours it fell to 579-972 grains per hour.\n** Physiologie des Athmens, &c. S. 91 und 94.\nNotwithstanding, therefore, that Prout failed to observe any decided increase in the quantity of carbonic acid gas thrown off by the lungs during digestion, and that Mr. Coa-thupe maintains from his experiments that the carbonic acid in the expired air increases with increased abstinence from food, and that its maximum quantity is before breakfast and immediately before dinner *, we must consider the evidence detailed above perfectly conclusive in proving that the quantity of carbonic acid evolved in respiration is considerably increased after a full meal.\nFasting. \u2014 In describing the effects of digestion upon the quantity of carbonic acid evolved from the lungs, we were led to refer to the manner in which the opposite condition of the body, or that of fasting, operates. That fasting diminishes the quantity of carbonic acid in the expired air is not only proved by the facts already mentioned, but also by the experiments of Scharling upon the human species, of Boussingault upon the turtle dove, and of Marchand upon frogs. The two last experimenters found that in very prolonged fasting the quantity of carbonic acid was greatly diminished.\nAlcohol. \u2014 Dr. Prout states that alcohol, and all liquors containing it which he had tried, have the remarkable property of diminishing the quantity of carbonic acid gas in the expired air much more than any thing else he had made the subject of experiment, and its effects were most remarkable when taken on an empty stomach. Vierordt mentions, in confirmation of Prout\u2019s observations on this point, that in four experiments, after having taken from one half to a bottle of wine, the percentage of carbonic acid had fallen, a quarter of an hour after this, from 4'54 to 4\u201901, and it continued to exercise this effect from one to two hours.f\nThe quantities of atmospheric air and carbonic acid are calculated in the original tables in cubic centimetres. In reducing these to English cubic inches, one cubic centimetre has been considered to be equal to -06102523 of an English cubic inch.\n* London, Edinburgh, and Dublin Philos. Magaz. vol. xiv. p. 409 and 413. The number of meals and the times at which they were taken explain the results obtained by Mr. Coathupe. He lunched at 1 o\u2019clock v. m., and at 2 p. m. the average percentage of carbonic acid gas was raised from 3-92 to 4-17, and thus so far in accordance with the experiments mentioned above. At 5^ p.m. he took a good dinner, with a pint of wine. Now, as alcohol diminishes the quantity of carbonic acid evolved from the lungs, this might have counteracted the effects of digestion for a time. It must also he remembered that Mr. Coathupe ascertained only the percentage, not the absolute quantity of carbonic acid evolved ; and Vierordt ascertained by experiment (Physiologie des Athmens, &c. S. 93) that when he drank wine at dinner the percentage of the carbonic acid in the expired air was diminished ; and that, though its absolute quantity was increased, this was not nearly to the same extent as when no wine was taken.. Were experimenters always to detail minutely the circumstances under which they performed their experiments, it would frequently be found, as in the present case, that results, apparently most discordant, are not so in reality.\nj- Wagner\u2019s Handw\u00f6rterbuch, band ii. S. 884 ; and Physiol, des Athmens, &c. S. 97.","page":347},{"file":"p0348.txt","language":"en","ocr_en":"348\nRESPIRATION.\nA strong infusion of tea has, according to Prout, an effect similar to alcohol.\nAccording to Dr. Fyfe, when a person has taken mercury or nitric acid for some time, the quantity of carbonic acid is diminished.\nConditions of the mind. \u2014 Prout found that anxiety and the depressing passions diminish the percentage of carbonic acid in the expired air ; and Vierordt, on two occasions, observed this effect, for a short time at least, from mental emotions, both of a joyful and of an opposite nature. Scharling remarked that in those persons who felt very anxious on being enclosed in the box used by him in his experiments, the evolution of carbonic acid gas from the body was much diminished.\nExercise. \u2014 Prout states that moderate exercise, as walking, seems always at first to increase the evolution of carbonic acid, but when continued it ceases to produce this effect, and when carried the length of fatigue the quantity is diminished : that violent exercise appears to lessen the quantity from the first, or if any increase occurs, this is trifling and transitory ; and that, after violent exercise, the quantity is much lessened. In Prout\u2019s mode of experimenting, the percentage of carbonic acid having been alone ascertained, we have no certain means of judging of the changes in the absolute quantity of carbonic acid evolved, as the increase in the number of respirations and in the bulk of the air respired, occasioned by exercise, was not taken into account. In the experiments of Seguin and Lavoisier already referred to, it was found that Seguin, when fasting and at rest, vitiated in the hour 1210 cubic inches of oxygen gas : by an amount of exercise equal to raising 15 lbs. to a height of 613 feet, this was increased to 3200 while still fasting, and to 4600 cubic inches, while digesting food. In Scharling\u2019s experiments, where the absolute quantity of carbonic acid gas evolved from the whole body in a given time was ascertained, the quantity of carbonic acid was increased during exercise. Vierordt ascertained that during the increased respiratory movements occasioned by moderate exercise, that on an average there was an increase per minute of 18*978 English cubic inches in the expired air, containing an increase of 1*197 cubic inch of carbonic acid gas, giving, however, an increase of carbonic acid gas in the expired air of only 0*140 per cent. There can, therefore, be no doubt that the evolution of carbonic acid gas from the lungs can be considerably increased by exercise.*\nTemperature. \u2014 The effects of low temperatures upon the respiratory process, as ascertained by Spallanzani and Treviranus upon snails and insects, by Marchand upon frogs, and by different observers upon the hyber-nating warm-blooded animals, are not appli-\n* G. R. Treviranus (Zeitschrift f\u00fcr Physiologie, vierter band, S. 29. 1831) and Newport (opera cit.) in their experiments upon insects, observed a marked increase in the exhalation of carbonic acid gas in these animals during active voluntary movements.\ncable to the human species, since the reduction of the temperature to a certain extent induces in these animals a lethargic condition, well known under the term hybernation, altogether different from its effects upon man and the other warm-blooded animals. Seguin and Lavoisier state that in their experiments, Seguin, in a temperature of 82\u00b0 Fahr., fasting and at rest, consumed, in the space of an hour, 1210 French cubic inches of oxygen ; while in a temperature of 57\u00b0 Fahr., he consumed in the same time 1344 cubic inches.* Crawford f, in experiments upon guinea-pigs, ascertained that these animals, in a given time, deteriorate a greater quantity of air in a cold than in a warm medium. The most perfect experiments on this point, at least on the human species, are those of Vierordt.J He ascertained, by numerous trials upon himself, the effects of temperature from 37\u00b0*4 to 75\u00b0*2 Fahr. From a table, showing the results obtained, both upon the respiration and the pulse, at each degree of the centigrade thermometer within the limits mentioned, he has constructed the following shorter table, where the first table is arranged in two divisions,\u2014the one containing the average of all the lower, and the other the average of all the higher temperatures. In the following table the measures of the expired air and carbonic acid have been reduced to English cubic inches.\nRespirations} Perm>nute { Volume of an expiration I in cubic inches\tJ\nExpired air)\t(\n------ car- Vper minute -<\nbonic acid j\t(\nBarometer, in English ) inches -\t-\t- /\nAverage of the lower temperature, 47\u00b0*24 F.\tAverage of the higher temperature, 66\u00b0*92 F.\tDifference between the higher and lower temp.\n72*93\t71*29\t1*64\n12-16\t11*57\t0*59\n33*44\t31*76\t1*68\n406*99\t366*97\t40*02\n18*25\t15*72\t2*53\n4*48\t4*28\t0*20\n29*719\t29*647\t\nThe experiments of Letellier\u00ff on warmblooded animals agree in their results with\n* M\u00e9moires de l\u2019Acad\u00e9mie Royale for 1789. f Experiments and Observations on Animal Heat, p. 311\u2014315. 2nd edit. 1788.\nX Wagner\u2019s Handw\u00f6rterbuch, band ii. S. 878, 879, und 880. Physiologie des Athmens, S. 73\u201482.\n\u00a7 Comptes Rendus, tom. xx. p. 795. 1845. Annales de Chimie et de Phys. tom. xiii. p. 478. 1845. Letellier has thrown the results of his experiments into the following table. He does not state whether he measured the temperature by Reaumur, or the","page":348},{"file":"p0349.txt","language":"en","ocr_en":"RESPIRATION.\n349\nthose of Yierordt. He found that the quantity of carbonic acid gas evolved from the body at the freezing point, was double of that at an elevated temperature, in the two mice and guinea-pig, and a little more in the canary and pigeon. There can, therefore, be no doubt that more carbonic acid gas is evolved from the body in a cold, than in a warm temperature.\nEffect of the seasons.\u2014Dr. W. F. Edwards* ascertained, by several well-devised experiments, that birds placed under exactly the same circumstances, and with the surrounding air of the same temperature, consumed more oxygen in winter than in summer, and this appears to be connected with that change in the constitution of the warm-blooded animals in the colder regions of the earth, by which they are enabled to generate more caloric in winter than in summer.\nBarometric pressure. \u2014 Legallois found that when warm-blooded animals breathed air in a vessel under an atmospheric pressure reduced to 30 centimetres (1 P811 English inches), the quantity of oxygen gas consumed was dimi-nished.f Prout, on the other hand, informs us, that, in every instance in his experiments, any remarkable increase in the percentage of carbonic acid in the expired air was accompanied by a sinking barometer. J Yierordt tested the effects of a range of the barometric scale between 330/// (29*309 English inches) and 340/// (30*197 English inches), and has thrown the results into a tabular form. The measure of the expired air was calculated under the ordinary pressure of 336w (29*841 English inches). He found that a rise of 5//A67, (the mean between the experiments at the lower and those at the higher pressures,) produced the following effects : \u2014\nIt increased the pulsations in one minute 1*3\n\u201e\trespirations ......... 0*74\n\u201e\texpired air (cubic in.) 35*746\nAs, however, the percentage of the carbonic acid in the expired air was greater at the lower than at the higher pressures, in the\nCentigrade scale, but we believe that it was the latter.\n\tSurrounding Temperature.\t\t\n\tFrom 15\u00b0to 20\u00b0\tFrom 30\u00b0to 40\u00b0\tAt the freezing point.\nFor a Canary For a Pigeon For two Mice For a Guinea Pig\tgrammes 0*250 0*684 0*498 2*080\tgrammes 0*129 0*366 0*268 1*453\tgrammes 0*325 0*974 0*531 3*006\n* De l\u2019Influence des Agens Physiques sur la Yie, chapitre vi.\nt Annales de Chimie et de Physique, tom. iv. p. 113. 1817.\nX Thomson\u2019s Annals of Philosophy, vol. iv. p. 335.\nproportion of 4*450 to 4*141, the difference between the absolute quantity of that gas in the expired air at the higher exceeds so little that at the lower pressures, that it may be reckoned as nil.*\nAge, sex, and constitution of body. \u2014 The quantity of carbonic acid evolved from the body is not only influenced by the ingesta and the varying conditions of the surrounding media, but also by the age, sex, and constitution of the body. The only important researches into the effects which these last conditions of the body have upon the evolution of the carbonic acid, are those of Andral and Gavarretf, and Scharling J ; and though they are far from having exhausted the subject, they possess the merit of having been carefully and accurately conducted, and of being carried on in the right direction. Andral and Gavarret availed themselves in their experiments of the apparatus suggested by Dumas and Boussingault. Part of this apparatus consists of a mask, which can be fitted airtight to the face, and having a tube on each side, on a level with the commissures of the lips, provided with valves permitting the external air to pass in, but preventing its passage outwards. In front of the mouth there is a large aperture for conducting outwards the expired air ; and to this a tube can be attached for conducting it into the \u00abreceivers and other parts of the apparatus prepared for ascertaining the quantity of carbonic acid gas. A person can breathe through this apparatus without constraint ; and the experiments were all performed between one and two o\u2019clock p.m., each lasting from eight to thirteen minutes, and the individuals experimented upon were placed, as far as possible, under the same conditions with regard to food, muscular exertion, and state of the mind. They experimented upon sixty-two individuals of different ages, and of both sexes. They restricted their valuation of the quantity of carbonic\n* Dr. Hutchinson (Medico-Chirurgical Transactions of London, vol. xxix. p. 228) has given some experiments upon the effects of an increased barometric pressure upon the frequency of the respiratory movements. These were made upon six persons before and after descending a mine, 1488 feet deep, where the barometric pressure was 1*54 inch more than at the level of the sea. As there was a difference of 10 degrees in the temperature at the top and bottom of the mine, this ought to be taken into account in judging of the results. The pulse was increased at the bottom of the mine on an average 1*3 per minute, and the respirations 2*4 per minute. The accounts given by travellers of the effects upon their respiration in elevated regions are so discordant that we can deduce no very satisfactory conclusions from them.\nf Annales de Chim. et de Phys. tom. viii. p. 129. 1843.\nJ Annalen der Chemie und Pharmacie, band xlv. S. 214. 1843, translated in Annales de Chim. et de Phys. tom. viii. p. 478. 1843. In Scharling\u2019s experiments, as in those of Andral and Gavarret, the absolute quantity and not the percentage of carbonic acid gas in the expired air was determined. In Scharling\u2019s first experiments, the carbonic acid gas given off at the external surface of the body was mixed with that given off by the lungs.","page":349},{"file":"p0350.txt","language":"en","ocr_en":"350\tRESPIRATION.\nacid evolved from the lungs to one hour, being perfectly aware of the fallacy of attempting to estimate from experiments so limited as to time, the quantity given off in the twenty-four hours. Scharling conducted his experiments in a different manner. He enclosed the individuals experimented on in a box, perfectly air-tight, and so large as to permit a person to work, read, or even sleep, during the experiment. Tubes were fixed in the box, to admit the external air freely, and to conduct the expired air into an apparatus fitted for determining the amount of the carbonic acid. The individuals experimented on remained in the box generally for an hour at a time, sometimes an hour and a half, but also often from thirty to forty minutes only ; and precautions were taken to keep up a free circulation of atmospheric air through the box during the whole of the experiment. His experiments were performed upon six persons, of different ages and of both sexes.\nAndral and Gavarret have drawn the following conclusions from their experiments:\n1. The quantity of carbonic acid gas exhaled from the lungs, in a given time, varies according to the age, the sex, and the constitution of individuals ; and that, independently of the weight of the body. 2. At all periods of life extending from 8 years (the earliest age subjected to experiments) up to the most advanced old age, the quantity of carbonic acid evolved from the lungs differs in the two sexes, but, c\u0153teris paribus, the male exhales a considerably larger quantity than the female. This difference is most marked between 16 and 40 years of age, during which period the male generally evolves nearly twice as much as the female. 3. In the male, the quantity of carbonic acid exhaled goes on continually increasing from 8 to 30 years of age, and becomes suddenly very great at the age of puberty. After 30 years of age it begins to decrease, and this so much the more decidedly as the person approaches extreme old age, at which period it may be reduced to the quantity evolved at 10 years of age. 4. In the female also, the evolution of carbonic acid increases from infancy up to puberty ; but at this period, contrary to what takes place in the male, it remains stationary, so long as the menstrual secretion continues natural. At the time the menses cease, the evolution of carbonic acid gas from the lungs undergoes a marked augmentation ; but after a while it begins to decrease, as in the male, and proportionally as she advances towards old age. 5. In the female, during gestation, the exhalation of carbonic acid from the lungs equals the quantity exhaled at the period of the cessation of the menses. 6. In both sexes, and at all ages, the quantity of carbonic acid is so much the greater, as the constitution is stronger and the muscular force more developed.\nThe most important of the data upon which the above inferences are founded are as follows: \u2014\nIn the male child, in his progress upwards\nfrom his 8th to his 15th years, the quantity of carbon given off by the lungs was raised, on an average, from 5 grammes (77\u2019165 Troy grains) to 8*7 grammes (134*267 Troy grains) per hour ; while in the female at the same age it w'as on an average 1 gramme (15*433 Troy grains) less per hour. In the male at 16 years of age, or soon after puberty, it suddenly increased to 157*416 Troy grains, on an average, per hour ; and from this period up to the age of 20 and 25 it gradually increased, on an average, to 172*849 and 191*369 Troy grains per hour. At this point it remained nearly stationary until about 40 years of age, when it began to undergo a slight diminution, but not to any great extent until 60 years of age. Adult females, who menstruated regularly, lost, on an average, 98*771 grains only of carbon, by the lungs, in an hour,\u2014a quantity not greater than that lost by girls. Take the average loss of carbon, by the lungs, in the male at 174*392 grains between the ages of 15 and 20 years, it is, on an average, 155*873 grains between 40 and 60 years,* and 141*953 grains between 60 and 80 years. In the female, at the period of the cessation of the menses, the loss of carbon is suddenly elevated from an average of 98*771 to 129*637 grains per hour; and a similar elevation, and nearly to the same extent, was observed in four females during pregnancy. In females between 50 and 60 years of age, the loss was 112*660 grains, and between 60 and 80 it was, on an average, 104*944 grains in an hour. In one female of 82 years, it was 92*595 grains, and in a male of 102, but remarkably hale for his years, it was 91*590 grains. In a male, aged 26, and remarkable for his muscular development, the loss was as high as 217*105 grains, while in another male, aged 45, of moderate height, but extremely feeble muscular development, it amounted on an average only to 132*723 grains an hour.* Scharling, after allowing seven hours for sleep to an adult, and nine for a child, calculates, from his experiments on six individuals, the amount of the loss of carbon from the body as follows : \u2014\n\tO) U\t\tQuantity of carbon\t\n\td <v\tWeight\texhaled in grains.\t\n\t\tofbodyin\t\t\n\tA\tTroy lbs.\tIn 24\tIn 1\n\t'-w \u25c4\t\thours.\thour.\nMale -\t16\t154*73\t3453*90\t143*91\n\t\t28\t219*70\t3699*50\t154*14\n\t -\t35\t175*49\t3386*77\t141*11\nAverage of men\t26\u00a3\t183*30\t3513*39\t146*39\nBoy\t9f\t58*96\t2054*53\t85*60\nGirl\t10\t61*64\t1929*89\t80*41\nAver, of children\t9|\t60*30\t1992*21\t83*10\nWoman\t19\t149*41\t2540*88\t105*87 f\n* Brunner and Valentin (opus cit. p. 567), from","page":350},{"file":"p0351.txt","language":"en","ocr_en":"RESPIRATION.\t351\nIn these experiments of Scharling the evo- relative amount of the loss by these two dif-lution of carbonic acid by the skin was in- ferent channels in an hour. In other respects, eluded, with that evolved through the mouth he has endeavoured to assimilate his experi-and nostrils ; and the quantity is calculated ments, in regard to the hour of the day, &c., for the twenty-four hours. But in some sub- to those of Andral and Gavarret, and has sequent experiments, by uniting the use of given the following comparative view of the the mask used by Andral and Gavarret with results : \u2014 the box, he has been enabled to ascertain the\n1.\tMale aged\t28 years 2.\t\u2014\t\u2014\t16 \u2014 3.\tBoy\t\u2014\t9| \u2014 4.\tYoung Woman 19 \u2014 5.\tGirl\t-\t- 10 \u2014\tTotal quantity of carbon from the whole body in Troy grains.\tCarbon from general surface of body.\tCarbon expired through the mouth and nostrils in Troy grains.\t\n\t\t\tScharling.\tAndral and Gavarret.\n\t181-183 169-763 101-086 128-340 95-622\t5-756 2-793 1-913 4-197 1-913\t175-426 166-969 99-172 124-143 93-709\t191-369 157-416 91-\t054* * 108-031 92-\t598f\nInfluence of the respiratory movements upon the evolution of carbonic acid from the lungs. \u2014 This point has been particularly examined by Vierordt in 171 experiments upon himself, and he has ascertained that the frequency, extent, and duration of the respiratory movements have a marked effect, not only upon the relative proportion of the carbonic acid gas in the expired air, but also upon the absolute quantity evolved from the lungs in a given time. J We shall afterwards find, when we come to describe the theory of respiration, that the results obtained by Vierordt are of considerable importance in a theoretical point of view.\nFrequency of the respiratory movements.\u2014 When the number of respirations is less than usual, the percentage of the carbonic acid in the expired air is increased, while its absolute quantity is diminished; on the other hand, when the respirations are more frequent than usual, the percentage of carbonic acid in the expired air is diminished, while its absolute quantity is increased. Vierordt endeavours to point out that the diminution in the percentage of the carbonic acid gas in the ex-\nsix experiments on themselves, calculate that 172-664 Troy grains of carbon were thrown off from the lungs in an hour.\nf This table is given in the form into which it has been thrown by Hannover (De Quantitate relativa et absoluta Acidi Carbonici ab homine sano et \u00e6groto exhalati, p. 17.\t1845) and the kilo-\ngrammes and grammes in the original table have been reduced to Troy pounds and Troy grains.\n* As the boy upon whom Scharling experimented was of slender form, he has taken the average of the results of Andral and Gavarret upon two boys of 10 and 8 years as the standard of comparison in this case.\nf Wohler and Liebig\u2019s Annalen der Chemie und Pharmacie, band lvii. S. 1. 1846. The male adult and the boy were naked during the experiment. _\n+ Physiologie des Athmens, vierter abschnitt, S. 102\u2014149.\npired air when the respirations are more frequent, probably bears a certain proportion to their frequency or length per minute, supposing their bulk to be the same. The operation of this law, according to Vierordt, may be illustrated as follows. Let us take the average number of respirations in a state of rest as 12, and suppose these to be doubled or increased to 24, the relative percentage of carbonic acid will be diminished by 0-8 ; if the number of respirations be again doubled, or increased to 48, the carbonic acid will suffer a still further diminution of 0-4 per cent. ; and if the respiration be again doubled, and increased to 96 per minute, the carbonic acid will suffer a farther reduction of 0 2 per cent. On the other hand, if the number of respirations be less than 12 (here taken as the normal number of respirations by Vierordt) by one half or reduced to 6 in the minute, the relative percentage of carbonic acid will be increased above what it is in the normal frequency by P6. If the percentage of carbonic acid in the expired air be 4-1, when the respirations are 12 in the minute, it will be 5*7 per cent, when the respirations are 6, and 2*7 per cent, when they are 96 in the minute. Proceeding upon the existence of this law, he supposes that if the respirations were increased from 96 to twice that number, or 192, the percentage of the expired air would suffer a farther reduction of only 0-l per cent. ; in other words, it would be reduced from 2-7 to 2\u20196 per cent. This last ratio, viz. 2 6, he believes to be the smallest percentage of carbonic acid gas that the expired air can present. If Vierordt be correct in supposing that the percentage of carbonic acid in the expired air has a fixed arithmetical proportion to the frequenc}' or length of the respiratory movements, we could, after determining the normal number of x-espirations, the bulk of air expired, and the percentage of carbonic acid","page":351},{"file":"p0352.txt","language":"en","ocr_en":"352\tRESPIRATION.\ngas, when the body is in a state of rest, be able to determine both the relative and the absolute quantity of carbonic acid gas in the expired air from the number of respirations alone, when these are either increased above, or diminished below the normal number, provided the bulk of each respiration continues equal. He has constructed the following table to illustrate the variations in the absolute quantity of carbonic acid gas occasioned by alterations in the frequency of the respiratory movements. The normal number of respirations is supposed to be 12, the average bulk of each respiration to be 500 cubic centimetres (30*5 English cubic inches), and the percentage of carbonic acid to be 4*1.\nNumber of respirations in a minute.\tPercentage of carbonic acid in the expired air.\tYolume of the expired air in a minute.\tYolume of carbonic acid gas in the expired air in a minute.\tYolume of carbonic acid gas in each expiration.\n\t\tMeasured in English cubic inches at a temperature of 98\u00b0*6 F., and under a barometric pressure of 29*841 English inches.\t\t\n6\t5*7\t183*000\t10*431\t1*738\n12\t4*1\t366*000\t15*006\t1*250\n24\t3*3\t732*000\t24-156\t1*006\n48\t2*9\t1464-000\t42*456\t0*884\n96\t2*7\t2928*000\t79*056\t0*823\nBulk of the air expired. \u2014 The quantity of air thrown out of the lungs at each expiration has also an influence upon the percentage and absolute quantity of carbonic acid gas in the expired air. Yierordt, in six experiments, found that while the average of carbonic acid gas in the expired air in a normal expiration in a state of rest was 4*78 per cent., in the deepest expiration he could make, it was 4*05 per cent.\nThe stoppage of the respiratory movements for a time has also a marked effect upon the quantity of carbonic acid in the expired air. Vierordt has made four series of experiments upon himself to ascertain the extent of this influence upon the quantity of carbonic acid evolved from the lungs. In the first series he shut his mouth and held his nose from 20 to 60 seconds (the longest period he could continue the experiment), and then made the deepest possible expiration. In the second series he made the deepest inspiration possible, then suspended the respiratory movement for a longer or shorter time, at the termination of which he made the deepest expiration. This experiment he was able to prolong to 70, 90, and even 100 seconds. In the third series he made an ordinary inspiration before suspending the respiratory movements, and after this suspension had continued for different periods up to 30 seconds,\nhe made an ordinary expiration. The fourth series of experiments was to ascertain the period of time after the stoppage of the respiratory movements when the percentage of carbonic acid gas becomes uniform in the different parts of the lungs and air passages, and this he found took place after 40 seconds. He has arranged the results of the three first series of experiments in several tables, exhibiting the difference between the percentage and absolute quantity of carbonic acid gas in the expired air at various periods, after the suspension of the respiratory movements under the circumstances mentioned, and when the respiratory movements proceed in the normal manner. In the first series of experiments, the percentage of the carbonic acid in the expired air, after the respiratory movements had been suspended 20 seconds, was higher by 1*73 than when these movements were normal, but the absolute quantity evolved from the lungs had diminished by 2*642 English cubic inches, and at the end of 55 seconds its percentage had increased 2*32, but its absolute quantity had diminished to the extent of 12*382 cubic inches. In the second series of experiments, where the deepest possible inspiration preceded, and the deepest possible expiration followed, the suspension of the respiratory movements, the absolute quantity of carbonic acid gas evolved from the lungs, for the first 15 seconds, was somewhat more than what would have occurred had these movements proceeded in the normal manner, but after this it began to diminish ; and when the respiratory movements had been suspended for 95 seconds, it was diminished to the extent of 14*078 English cubic inches, though its percentage had considerably increased. At the end of the 100 seconds, the percentage of the expired air was 3*08 above the normal quantity in ordinary respiration. In the third series of experiments, the carbonic acid in the expired air, at the end of 30 seconds, was 1*55 per cent, above the normal quantity. These experiments prove, therefore, that when the respiratory movements have been suspended for a time, the percentage of carbonic acid in the expired air will increase, but the absolute quantity evolved from the lungs will be diminished, so that the increase in the percentage of this gas does not by any means compensate for the diminished quantity of air passing through the lungs.\nWhen the same air is breathed more than once, the quantity of carbonic acid in it is increased. Allen and Pepys * state that air, passed 9 or 10 times through the lungs, contained 9 5 per cent, of carbonic acid gas ; and the greatest quantity obtained, in air breathed as often as possible, was 10 per cent. Mr. Coathupef found the average quantity of carbonic acid gas, in air in which warmblooded animals had been confined until they were becoming comatose, to be 10*42 per\n* Philos. Transact, of London for 1808,\nf Opus cit.","page":352},{"file":"p0353.txt","language":"en","ocr_en":"RESPIRATION.\n353\ncent. ; while, if they were allowed to remain in it until they had become asphyxiated, it contained 1275 per cent. Vierordt, in three experiments, breathed, from ]i to 3 minutes, a volume of air amounting to 427 English cubic inches, and found, on an average, the carbonic acid gas 1* * * * * \u00a75 per cent, above that contained in air breathed only once.\nThe percentage of carbonic acid in the expired air differs at diff\u00e8rent periods of the same expiration. As the air expelled in the first part of an expiration consists chiefly of that contained in the trachea and upper part of the air passages, its amount of carbonic acid gas must necessarily be smaller than that expelled at a later period of the expiration. Allen and Pepys found the carbonic acid gas in the first and last portions of air in a deep expiration to differ as widely as 35 and 9*5 per cent. Dalton states that while the average carbonic acid in an ordinary expiration is 4 per cent., the last portion of a forced expiration contains 6 per cent. Vierordt divided the air of an ordinary expiration as far as possible into two equal parts, and in twenty-one experiments ascertained that while the average quantity of carbonic acid in the whole expiration was 4*48, the first half contained 3*72 per cent., and the last half 5*44 per cent. We have already seen, that Vierordt concludes from his experiments that the air, after a sojourn of about 40 seconds in the respiratory apparatus, has the same percentage of carbonic acid gas in the different parts of the lungs and air passages.\nFrom the above details, it must be obvious that nearly all the attempts made to estimate exactly the average quantity of carbon evolved in the form of carbonic acid gas from the body in the 24 hours are entitled to very little confidence. The greater number of these are founded on a few experiments performed upon one or a very small number only of individuals in a state of rest, and upon the result of a few respirations in some cases performed under constraint. The estimate of the amount of loss of carbon in the 24 hours from the lungs and external surface of the body, based upon the direct method of experiment, in which the greatest number of the circumstances that influence the evolution of carbonic acid gas from the lungs were taken into account, is undoubtedly that of Scharling, though this even must be regarded as an approximation only to the truth. Suppose we take the average estimate of the two adult males between 28 and 35 years of age for the 24 hours, as given by Scharling *, the loss of carbon by the lungs and skin is 3543*13 Troy grains, or 7*382 oz. Troy, -f- Liebig J has endeavoured\n* Vide table given in p. 350.\nf The estimates of the average loss of carbon, in the form of carbonic acid gas, from the lungs in the twenty-four hours by other experimenters, differ considerably. Lavoisier and Seguin estimated the loss of carbonic acid gas at 14,930 cubic inches, which they believed would yield 2776-304 grains Troy; Messrs. Allen and Pepys at 39,534 cubic inches''of carbonic acid gas, containing rather more than 11 oz. Troy of carbon ; and Mr. Coathupe at 10,666 cubic\nVOL. IV.\nto ascertain the quantity of carbon lost at the lungs and skin in the 24 hours by the indirect method of research, which he maintains to be by far the most trust-worthy. He proceeded to ascertain the quantity of charcoal in the daily food and drink of a body of soldiers, and after deducting the comparatively small quantity of this substance that passes off in the faeces and urine, the remainder was taken as the amount of carbon that unites with oxygen, and escapes in the form of carbonic acid gas by the lungs and skin. From the data thus obtained he calculates that an adult male, taking moderate exercise, loses 13*9 oz. of carbon daily by the lungs and skin ; and that 37 oz. of oxygen gas must be daily absorbed from the atmospheric air for the purpose of converting this charcoal into carbonic acid gas. From similar experiments upon the inmates of the Bridewell at Marienschloss (a prison where labour is enforced), he calculates that each individual lost in this manner 10*5 oz. of carbon daily ; while in another prison, where the inmates were deprived of exercise, this loss amounted only to 8*5 oz. daily. * Allowing that this indirect method of research is more accurate than the direct,\u2014a point which we are not at present prepared to determine, \u2014 the accuracy of the data upon which Liebig\u2019s inferences rest regarding the quantity of carbonic acid exhaled from the lungs and skin in an adult using moderate exercise, has been called in question by Scharling. I He endeavours to prove, by an analysis of the food and drink allowed to the sailors on board of his Danish Majesty\u2019s vessels of war, that the whole carbon taken daily into the body of each of these individuals must be somewhat less than 10J oz.; yet these sailors are subjected to harder work than ordinary seamen. J\nThe quantity of carbonic acid gas evolved from the body in respiration varies greatly in the different divisions of the animal kingdom. It is greater in birds, in proportion to their bulk, than in the cold-blooded vertebrata, and still smaller in the invertebrata, with the exception of insects. \u00a7 The ascertainment not\nfeet of carbonic acid gas, yielding 2386-27 grains, or 5-45 oz. avoirdupois. Vierordt, from numerous experiments on himself, ascertained that when in a state of rest the quantity of carbonic acid gas exhaled from the lungs per minute was for the maximum 452 cubic centim\u00e8tres (27-572 Eng. cub. in.), for the minimum 177 cub. cent. (10-797 Eng. cub. in.), and for the average 261 cub. cent. (12-261 Eng. cub, in.), so that the relation of the minimum and maximum was 100: 255. If the quantity of carbonic acid evolved from the lungs differs so much at different times in the same individual in the minute, and is so materially influenced by the varying conditions of the body, how difficult must it be to ascertain the average quantity during the twenty-four hours.\nX Animal Chemistry, &c., edited by Dr. Gregory, p. 13 ; 3rd edit. 1846.\n* Opus cit. p. 46.\nf Annalen der Chemie und Pharmacie, von Wohler und Liebig, Band lvii. S. 1. 1846.\nt Opus cit. p. 9.\n\u00a7 The results of the various experiments upon\nA A","page":353},{"file":"p0354.txt","language":"en","ocr_en":"354\nRESPIRATION.\nonly of the absolute quantity of carbon which escapes from the body in the form of carbonic acid gas in the different classes of animals, but also the relative proportion of this to the weight of the body, is a matter of considerable physiological interest, especially with reference to the source of animal caloric. From the experiments of Scharling, Andral, and Gavarret, it is evident that the young of the human species relative to their weight consume considerably more oxygen gas, and evolve more carbonic acid gas by respiration, than the middle-aged ; and that the latter again evolve more carbonic acid than those far advanced into old age. Valentin and Brunner have calculated, from experiments performed on Valentin, who at the time was 33 years of age, that for every gramme weight (15\u2018433 Troy grains) of his body, there was evolved '0089 Troy grain of carbonic acid gas, containing \u20220024 Troy grain of carbon ; and this calculation approximates pretty closely to one based upon the results of Andral and Gavarret upon the evolution of carbon, combined with those of Quetelet upon the average weight of the body at this period of life. * * The following table, calculated from the experiments of different observers, to show the quantity of carbon consumed in the 24 hours for every 100 grammes weight (1543-3 Troy grains) of the body in the four divisions of the verte-brata, is given by Vierordt : \u2014\nTroy Grains.\nTench (Proven\u00e7al and Humboldt) *370 =\t1\nFrog (Marchand)............... 1*342 = 4\nMan (Scharling) .............. 4-506= 12\nPigeon (Boussingault)......... 42*317 = 114\nQuantity of oxygen absorbed at the lungs. \u2014 That a quantity of oxygen gas greater than what is necessary to form the carbonic acid gas in the expired air disappears from the inspired air, is now placed beyond a doubt. The quantity of oxygen gas that disappears from the inspired air by absorption at the lungs is not uniform, even in the same individual, for any length of time, and the variations in this respect are in all probability determined by the same circumstances which affect the evolution of carbonic acid gas, the absorption of oxygen being increased when the evolution of carbonic acid is increased, and vice versa. Dalton calculated that he himself respired 500 cubic feet of atmospheric air, containing 105 cubic feet of oxygen, in the 24 hours, and that 25 cubic feet of the oxygen, weighing 15,120 grains, or 2*6 lbs. Troy, were absorbed at the lungs. Valentin and Brunner, in 34 analyses of the air expired\nby 3 individuals between 33 and 54 years of age, found the average quantity of oxygen gas to be 16-033, the maximum 17*246, and the minimum 14-968 parts by volume in the 100 parts of the expired air. Proceeding on these results of Valentin and Brunner, we may estimate the average amount of oxygen that disappears from the inspired air at 4*78 by volume in the 100 parts.\nWhile the experiments upon the relation of the quantity of oxygen absorbed at the lungs to that of the carbonic acid gas evolved, made by Lavoisier, Sir H. Davy, and Dalton on the human species, by Legallois, Dulong, Despretz, and Dr. W. F. Edwards upon the warm-blooded animals, by Treviranus upon several coldblooded animals, and by Marchand upon frogs, all concur in making the oxygen absorbed greater than what is necessary to form the carbonic acid exhaled, they exhibit very considerable differences in the relative proportions of the absorbed oxygen and exhaled carbonic acid gas. In some of these experiments, the oxygen absorbed was considerably greater than what is necessary to form the carbonic acid gas. In Marchand\u00e9 experiments on frogs subjected to prolonged fasting, the relation of the oxygen absorbed to the carbonic acid evolved constantly increased, until it amounted to between 410\u2014430 : 100.* Valentin and Brunner, in their experiments on the human species, found the relative proportions of these two gases to approximate so closely to their diffusive volumes, that they believed the small difference between the results obtained by actual experiment and when calculated according to the law of the diffusion of gas, discovered by Graham, arose from incidental circumstances ; and as. the diffusive volume of carbonic acid gas is to oxygen gas as 1 I P1742, they maintain that for every 1 volume of carbonic acid gas evolved from the blood, 1*1742 volume of oxygen gas is absorbed. Valentin has given the following table, constructed from facts furnished by Quetelet, Andral, and Gavarret, conjoined with calculations of the relative quantities of oxygen absorbed and carbonic acid evolved according to the law of the diffusion of gases, to exhibit the weight of the body, the quantity of carbon consumed in respiration, and the probable amount of oxygen absorbed and carbon consumed at the different periods of life in the human species f : \u2014\nthe quantity of carbonic acid evolved in respiration in different classes of animals up to the period when the work was published, are thrown into a tabular form in Burdach\u2019s Physiologie, 2nd edition, translated by Jourdan, tom. ix. p. 512.\n* A table constructed on these data, exhibiting the probable quantity of carbon which combines with oxygen to form the carbonic acid gas evolved at the lungs at different ages in the human species, is given at p. 569 of Valentin\u2019s Lehrbuch.\n* At page 568 of Valentin\u2019s Lehrbuch are two tables exhibiting the relative proportions of oxygen gas absorbed and carbonic acid evolved, as ascertained by direct experiment, and as calculated according to the law of the diffusion of gases. We shall have occasion to make some remarks on this subject when we come to discuss the theory of respiration.\nf Opus cit. p. 571. The weights and measures in the original table are here reduced to Troy weight and English cubic inches.","page":354},{"file":"p0355.txt","language":"en","ocr_en":"RESPIRATION.\n355\nYears of age.\tAverage weight of body in Troy pounds.\t\t\tCarbon consumed, in Troy grains.\t\tQuantity of oxygen which disappears from the inspired air. In grains.\t\tOverplus of oxygen above what is necessary to form the carbonic acid gas. In Troy grains.\t\tVolume of oxygen that disappears from the inspired air under a pressure of 2 9-92 inches, and a temperature of 32\u00b0 F. In English cubic inches.\t\n\t\t\t\tIni hour.\tIn 24 hours.\tIn lhour.\tIn 24 hours.\tIn lhour J\tIn 24 hours.\tIn lhour J\tIn 24 hours.\n8\t\t59-62\t\t77*165\t1864-306\t240-955\t5782-806\t35-233\t845-604\t526-907\t12645-770\n15\t\t124-34\t\t134-267\t3222-410\t419-252\t10062-069\t61-207\t1468-974\t1154-142\t27699-422\n16\t\t143-05\t\t166*676\t4000-233\t520-447\t12490-852\t75-976\t1823-439\t1432-669\t34384-076\n\t|\tn 64-13)\t1\t\t\t\t\t\t\t\t\n18\u201420\ti\tto\t\t175-936\t4222-468\t549-399\t13184-782\t80-359\t1928-631\t1512-432\t36298-371\n\t1\tU 74-15 J\tr\t\t\t\t\t\t\t\t\n\t1\tf 174T5 )\ti\t\t\t\t\t\t\t\t\n20\u201424\tJ\tto\t\t188-282\t4518-782\t587-904\t14110-083\t85-622\t2054-934\t1618-436\t38842-098\n\t1\t1184-36 J\tt\t\t\t\t\t\t\t\t\n\ti\tf 184-36 )\t\t\t\t\t\t\t\t\t\n40\u201460\t\tto\t\t155-873\t3740-959\t486-710\t11681-052\t71-099\t1706-395\t1339-847\t32156-346\n\ti\tL 175*49J\tr\t\t\t\t\t\t\t\t\n\t1\tf 175-49 )\ti\t\t\t\t\t\t\t\t\n60\u201480\t\u00ab\tto\t\t141-983\t3407-606\t443-34\t10640-250\t64-926\t1558-239\t1220-478\t29291*495f\n\t\t(164-02J\tr\t\t\t\t\t\t\t\t\nFrom the details given above we may obtain information of considerable importanen on several practical points. A consideratioe of the large quantity of atmospheric air passing through the lungs in the 24 hours, and the extent to which it is vitiated by this in the removal of a part of its oxygen and the substitution of a quantity of carbonic acid, gas, will assist us in acquiring definite information regarding the amount of ventilation required in the apartments of our private and public buildings. It appears that between 400 and 500 cubic feet of atmospheric air pass daily through the lungs of an adult enjoying moderate exercise; and the estimate of Dalton, that 23 cubic feet of oxygen gas are, during the same period, aborbed at the lungs, is probably not far from the average. The same air cannot be breathed twice without inducing prejudicial effects, so that at each inspiration entirely fresh air ought to be supplied, or the air already breathed ought to be so largely diluted by the admission of fresh air as to be restored very nearly to its original composition. Leblanc informs us, that in the Chamber of Deputies in Paris, where the system of ventilation is based upon the principle of furnishing to each individual from 10 to 20 metres cubes (353*316 to 706 331 English cubic feet) of air per hour, the air issuing from the apartment contained from 2 to 4 of carbonic acid gas in the 1000 parts by weight.* The quantity of pure atmospheric air here furnished is probably somewhat insufficient, if the presence of 1 part of carbonic acid in the 100 of atmospheric air be likely to act prejudicially when breathed for a long time\n* Annales de Chimie et de Physique, troisi\u00e8me s\u00e9rie, torn. v. p. 241. 1842. In the Model Prison at Pentonville from 30 to 45 cubic feet per minute, or from 1800 to 2700 cubic feet per hour, of pure fresh air is made to pass into every cell. (Report of the Surveyor-General on the Construction, &c. of Pentonville Prison. 1844.)\ncontinuously. From Dr. Snow\u2019s experiments, it appears that the prejudicial effects of breathing air deteriorated by respiration, is not entirely due to the presence of an increased quantity of carbonic acid gas, but also in a considerable degree to the diminution of the oxygen. He found that birds and mammalia introduced into an atmosphere containing only from 16 to 10i per cent, of oxygen soon died, though means were adopted for removing the carbonic acid formed by respiration.* The increase of the carbonic acid gas to 12 and 20 per cent., provided the oxygen gas was still as high as 21 per cent., did not appear to enfeeble the vital actions more rapidly than the diminution of the oxygen to the extent above stated. Any notable diminution in the percentage of the oxygen gas, even when no carbonic acid is present, cannot take place without danger to the warm-blooded animals f, and the carbonic acid in the air respired acts more or less energetically in destroying life, as it has been produced at the expense of the oxygen of the air, or been added to it already formed.J\n* Edinburgh Medical and Surgical Journal, vol. lxv. 1846. A green-linnet was confined in a vessel containing 2000 cubic inches of air, consisting of 16 of oxygen and 84 of nitrogen in the 100 parts by volume, and it died in ten minutes. A mouse was introduced into the same vessel filled with air containing 10\\ per cent, of oxygen, and in five minutes it was no longer able to stand.\nf There is a marked difference in this respect between the cold-blooded and warm-blooded animals. Yauquelin (Annales de Chimie, tom. xii. p, 271.1792) in his experiments upon some snails, found that when confined in a quantity of air, all the oxygen had disappeared at the time of their death; and Spallanzani observed the same thing in a few of his experiments on the same animals. Matteucci (Le\u00e7ons sur les Ph\u00e9nom\u00e8nes Physiques des Corps Vivants, p. 115. 1847), obtained similar results on a torpedo confined in a limited quantity of water.\nJ Dr. Snow infers from his experiments on the lower animals that in the human species \u201c five or\nA A 2","page":355},{"file":"p0356.txt","language":"en","ocr_en":"RESPIRATION.\nThe experiments on the effects of.diminished frequency of the respirations in reducing the amount of carbonic acid gas evolved from the blood in a given time, are in accordance with observations made on the state of the blood and its circulation, when this condition has been induced in man or in the other warm-blooded animals. A diminution in the frequency of the respiratory movements occasionally occurs to a notable extent in the course of some diseases, and this deserves the careful attention of the practitioner, as it is likely to lead to very serious consequences.* * * * \u00a7\nThe greater length of time that the respirations may be suspended without inducing insensibility, when a deep expiration followed by a deep inspiration has immediately preceded, affords additional illustration of the procedure which a person ought to adopt when he wishes to suspend, during diving, &c., the respirations for the longest period consistent with his safety. The manner and the order in which the vital actions are brought to a stand when the chemical changes between the blood and the atmospheric air are arrested, have been discussed under the article Asphyxia.^\nsix per cent, by volume of carbonic acid gas cannot exist in the air without danger to life, and that less than half this amount will soon be fatal, when it is formed at the expense of the oxygen of the air.\u201d (Opus cit. p. 54.) Leblanc ascertained that an addition of 3 or 4 per cent, by weight of carbonic acid formed by the combustion of charcoal, and at the expense of the oxygen of the air respired, proved instantly fatal to dogs, while it required the addition of 30 or 40 per cent, of pure carbonic acid gas to the atmospheric air to produce the same effect. The great activity of air deteriorated by the burning of charcoal in producing asphyxia, Leblanc attributes to the presence of carbonic oxide. He states that birds placed in air containing one per cent, of this gas, die in two minutes (Opus cit. pp. 240 and 245). Legallois (Annales de Chimie et de Physique, tom. iv. p. 113. 1817) had previously performed experiments, from which it may be inferred that an addition of somewhat more than 20 per cent, of carbonic acid to the atmospheric air, is sufficient to bring the evolution of carbonic acid from the blood in the lungs to a stand in the warm-blooded animals, and that, when the percentage of carbonic acid in the inspired air is increased to above 30, part of this gas is absorbed by the blood.\n* We have given some illustrations of this in pointing out the manner in which division of the vagi nerves causes death. (Edinburgh Medical and Surgical Journal, vol. li. p. 298 to 302. 1839.)\nf We have published a series of experiments (Edinburgh Medical and Surgical Journal, vol. lv. 1841) which go to support the account given of the manner in which the vital actions are arrested in asphyxia in the article referred to. In this we obtained satisfactory proof of the opinion of Bichatupon the effects of the venous blood in suspending the sensorial functions. In an excellent experimental essay on this subject, published subsequently to our essay (Edinburgh Med. and Surg. Journal, vol. lxiii. 1845), the author maintains, in opposition to the doctrine laid down in the article Asphyxia, \u201c that the flow of blood through the lungs is arrested in consequence of the venous blood acting as an excitant to the minute branches of the pulmonary veins and causing their contraction.\u201d In our experiments we found that, when the suspension of the respiration had been\nExperiments have been made by Nysten , by Mr. Macgregorj-, Dr. Malcolm J, and by Hannover \u00a7, upon the quantity of carbonic acid gas evolved from the lungs in some diseases, but these have not yet been carried sufficiently far to furnish us with any practical or theoretical conclusions of importance.\nDifferences between arterial and venous blood. \u2014 A knowledge of the chemical and physical differences between arterial and venous blood, or, in other words, between the blood immediately before and immediately after it has passed through the lungs and been subjected to the action of the atmospheric air, constitutes part of the data requisite for discussing the Theory of Respiration. Although many able chemists and physiologists have of late years directed their attention to this subject, yet, from its inherent difficulties, much discrepancy of observation and conflicting evidence still require to be cleared up and reconciled. Most, if not all, of the comparative analyses of the venous and arterial blood hitherto published are of considerably less value for our present purpose than they may at first appear, since only those of the venous blood flowing from the right side of the heart, and the arterial blood flowing from the left side of the heart or along the arteries, ought properly to be taken into account. The blood returning along the veins of the abdominal viscera, and entering the heart by the cava inferior, differs in composition from that entering the heart by the cava superior, for, independently of other reasons, a quantity of water and certain substances taken into the stomach are absorbed by the mesenteric and gastric veins. The composition of the blood in the large veins at the lower and lateral parts of the neck must also be somewhat affected by the lymph and chyle poured into that portion of the venous system. The analyses of venous and arterial blood taken at the same time from the carotid artery and the jugular vein, \u2014 the plan most generally followed in these researches, \u2014 are better fitted for throwing light upon the changes the blood undergoes in the perform-\ncarried so far as to arrest the flow of blood through the lungs, the admission of atmospheric air was instantaneously followed by the renewal of the passage of the blood to the left side of the heart, \u2014 a fact incompatible with this opinion, seeing that the bloodvessels are endowed with that kind only of contractility which manifests itself by slow contractions and equally slow relaxations.\n* Recherches de Physiologie et de Chimie Pathologique. Seconde section. 1811.\nj- Edinburgh Monthly Journal of Medical Science, vol. iii. p. 1. 1843.\n| Transactions of British Scientific Association, for 1840, p. 87.\n\u00a7 De Quantitate relativa et absoluta Acidi Car-bonici ab Homine sano et \u00e6groto exhalati. 1845. Hannover, in his experiments, employed the apparatus of Scharling, and was enabled to ascertain the absolute quantity of carbonic acid evolved from the body; while the other experimenters ascertained its percentage only. There can be no doubt that the plan adopted by Hannover is the one which ought to be followed.","page":356},{"file":"p0357.txt","language":"en","ocr_en":"RESPIRATION.\n357\nance of nutrition and secretion than of respiration.\nThe most marked difference, more especially in warm-blooded animals, between arterial and venous blood is that of colour, \u2014 arterial blood being of a scarlet red, and venous blood of a dark Modena hue. The extent of this difference of colour between the blood in the arteries and in the veins varies in the different vertebrata, and is greater in birds and in the mammalia than in reptiles and fishes ; and it also varies in different conditions of the body and surrounding media in the same animal. In animals exposed to artificial high temperatures* * * \u00a7, or living in warm climates f, when the energy of the respiratory function is naturally diminished, the venous blood may be of a brighter colour than usual, while the arterial may be less so, and it may then be difficult to distinguish the one kind from the other. In certain cases of high febrile excitement of the circulation, as in acute rheumatism when the blood passes rapidly and abundantly through the lungs, the blood in the veins may be of a scarlet colour : on the other hand, where the aeration of the blood is imperfect, as during the state of hybernation, in certain diseases, or from some mechanical impediment to the free passage of the air into the lungs, the blood flowing along the arteries approaches more or less the dark colour of venous blood.\nThe temperature of the arterial blood in the left side of the heart, aorta, and large vessels springing from it, is higher than the venous blood by from 1\u00b0 to 2\u00b0 Fahr., according to Dr. John Davy}, and 1\u00b0-01 C (1\u00b0*818 Fahr.) on an average, according to Becquerel and Breschet. \u00a7 According to Dr. Davy, the capacity of venous blood for caloric is 852, that of arterial blood 839. ||\nThe specific gravity of venous is somewhat greater than that of arterial blood. Dr. Davy gives the specific gravity of arterial blood as 1050, that of venous as 1053. H Some of those who have published analyses of both kinds of blood, procured more solid materials and less water from venous than from arterial blood ; others again have obtained the opposite result ; while Denis, in his analysis of the blood of a dog, observed no difference in this respect. The number of instances, \u2014 taking the more trust-worthy analyses only into ac-\ncount,\u2014 where the quantity of water was greater in the arterial than in the venous blood decidedly preponderates. In all probability the relative quantity of water in the two kinds of blood is determined by the relative extent of the loss of that fluid by the arterial blood at the kidneys, lungs, skin, &c., and of the supply entering the veins from without, but chiefly through the mesenteric veins.\nA larger quantity of fibrin has been obtained by some analysts from arterial than from venous blood in man and in the domesticated animals; others again have procured a larger quantity from venous than from arterial blood ; while a few have obtained dissimilar results in their analyses of these two kinds of blood in different genera of animals, and even in different individuals of the same species.* In the greater number of the analyses, however, more fibrin was obtained from arterial than from venous blood, -j- According to Denis and Scherer, the fibrin of the two kinds of blood differs in regard to its solubility in nitre. When a portion of well-washed fibrin from venous blood is triturated with a third part of nitre, and four times its weight of water, and a small quantity of caustic potass or soda is then added, it dissolves into a gelatinous mass, having the chemical characters of albumen ; while the fibrin from arterial blood similarly treated undergoes no such changes.\nThe blood-corpuscles are more abundant in arterial than in venous blood, according to Pr\u00e9vost and Dumas, Lecanu and Denis ; according to Meyer, Hering, and Nasse, they are more abundant in the venous blood ; while the analyses of Letellier and Simon tend to show that the proportion is fluctuating. According to Simon, the blood-corpuscles of arterial contain less h\u00e6matin than venous blood, while the quantity of globulin is variable. Mulder states that the chemical composition of h\u00e6matin is the same whether derived from arterial or venous blood.X\nThe statements made regarding the relative proportions of the albumen, fat, osmazone, and salts in the two kinds of blood, differ too much to justify us in attaching any importance to them, \u2014 a remark which, as yet, we are afraid applies with too much truth to most of the other statements regarding the chemical differences between the two kinds of\n* Nasse (article Blut, in Wagner\u2019s Handw\u00f6rter-* Crawford. Experiments and Observations on bucb der physiologie, Band i. S. 171) states that Animal Heat, p. 309. 3rd edit.\tthe difficulty of conducting a correct quantitative\nf Dr. J. Davy. London Phil. Transact, for 1838, anaiySis 0f the fibrine of the blood is sufficient to ac-p. 28.\tcount for these discrepancies.\nX Researches, Physiological and Anatomical, vol. j. We refer those who may wish to obtain more i. p. 147. 1839. At page 211 of the same volume, detailed information upon this and some other points another series of experiments is given, in which the connected with the chemical differences between difference in temperature varied from 1\u00b0 to 3\u00b0 F. the arterial and venous blood, with references to\n\u00a7 Annales des Sciences Naturelles, 2me s\u00e9rie, tom. the different authors who have investigated this vii. p. 94. 1837. Becquerel and Breschet, in their suhject, to Nasse\u2019s Treatise, entitled Das Blut, &c., experiments, used a thermo-electric apparatus. They and tbe article by him in Wagner\u2019s Handw\u00f6rter-found the difference of temperature between the two buch aiready referred to, and the first volume of kinds of blood diminish as the blood-vessels are more gjmon\u2019s Animal Chemistry, translated for the Sy-distant from the heart.\tdenham Society, by Dr. Day.\n|| Researches, Physiological and Anatomical, vol.i. + The Chemistry of Vegetable and Animal Phy-p. 146.\tsiology. Translated from the Dutch by Fromberg.\nT Opus cit. vol. ii. p. 22.\tpart H. p. 334.\nA A 3","page":357},{"file":"p0358.txt","language":"en","ocr_en":"358\nRESPIRATION.\nblood, mentioned above. Michaelis *, and Marcet and Macairef, in their ultimate or elementary analyses of both kinds of blood, found more carbon and less oxygen in venous, and less carbon and more oxygen in arterial blood; but Berzelius has adduced sufficient reasons to induce us to doubt whether, in such investigations, at least as at present conducted, the distinctive characters of the two kinds of blood can be preserved during the analysis, and that they are deserving of any confidence. J\nA larger quantity of fixed carbonic acid has been obtained from venous than from arterial blood by Mitscherlich, Gmelin, and Tiedemann. \u00a7\nIt is now placed beyond dispute that free gases exist in the blood, and it becomes a point of great importance in deciding upon the true theory of respiration to ascertain their nature, quantity, and relative proportions in the two kinds of blood. Pour methods have been followed in procuring the free gases from the blood. 1. By the application of heat. 2. By the use of the air-pump. 3. By agitation of the blood with other gases. 4. By the respiration of other gases than atmospheric air.\nThe first of these methods is imperfect, as the albumen coagulates when the temperature is raised towards the boiling point, and may retain gases present in the blood. The second method is also liable to lead to negative results, unless the air-pump employed be of the best construction, for, according to Magnus, it is not until the pressure of the air within the bell-glass is reduced to one inch, that the gases begin to escape from the blood. In such experiments it is also necessary to employ blood from which the fibrin has been removed, for coagulated blood will retain the free gases, and prevent their escape.\nSir H. Davy stated that by raising the temperature gradually to 200 Fahr., he obtained from 12 cubic inches of the arterial blood of a calf 1T^ cubic inch of carbonic acid gas, and of a cubic inch of oxygen || ; and that he procured carbonic acid gas from human venous blood heated to 112 Fahr.Tf Enschut assures us that, by subjecting blood to the temperature of boiling water, he obtained carbonic acid gas both from venous and arterial blood, and a greater quantity from the former than the latter kind of\n* Diss. Inaug. de Partibus Constitution] s singula-rium Partium Sanguinis arteriosi et venosi. Berolini, 1827.\nf Annales de Chimie et Physique, tom. li. p. 382. 1832.\nJ Lehrbuch der Chemie, Band iv. S. 99, 100. Dresden, 1831.\n\u00a7 Zeitschrift f\u00fcr Physiologie, Band v. 1833. Mitscherlich, Gmelin and Tiedemann, by the addition of acetic acid, and the application of heat, obtained from 1000 parts of venous blood at least 12-3 parts, and from the same quantity of arterial blood 8-3 parts of combined carbonic acid.\n|| Beddoes\u2019 Contributions to Physical and Medical Knowledge, p. 132. 1799.\nIdem opus, p. 134.\nblood.* * \u00a7 It is alleged that Brande obtained carbonic acid gas both from venous and arterial blood in considerable quantity by the use of the air-pump-)-; and Scudamore states that he procured it by the same means in variable quantities from venous blood.J Col-lard de Martigny\u00ff and Enschut || procured carbonic acid gas both from venous and arterial blood, by placing them in the Torricellian vacuum, and a larger quantity from the former than from the latter. Nasse, sen.1T, Stevens**, Dr. G. Hoffman \u25a0j--)-, Enschut j j, Dr. Maitland $$, and Bischoff || ||, obtained carbonic acid gas from venous blood on agitating it with hydrogen, or by allowing this gas to stand over the blood for several hours. The existence of free carbonic acid gas in the blood was still, however, regarded by some physiologists as very problematical, since several trust-worthy and careful experimenters, such as Dr. J. Davy HIT, Mitscherlich, Gmelin,\n* Dissertatio Physiologico-Medica de Respira-tionis Chymismo, p. 96 to 99.\t1836. Enschut, in\none set of experiments, obtained in this manner from 40 cubic centimetres (2-440 English cubic inches) of each kind of the blood of the calf, 2 to 4 cubic centimetres (-12205 to -24410 English cubic inches) of carbonic acid gas from venous blood, and 1 to 2-5 cubic centimetres (-061025 to -15256 English cubic inches) of the same gas from arterial blood, p. 99. Enschut points out various precautions necessary to be observed to secure accuracy in such experiments, a want of attention to which, he believes, was the cause of the failure of Dr. J. Davy, M\u00fcller, and others, in their attempts to obtain carbonic acid gas from blood by heat, p. 100\u2014104.\nf Sir Everard Home, in London Philos. Trans, vol. xxix. p. 172. 1818. It is stated by Sir Everard (p. 181), that Mr. Brande obtained carbonic acid in the proportion of 2 cubic inches for every ounce of blood, \u2014 a quantity so large, and obtained apparently with such facility, as to raise insuperable suspicions regarding the accuracy of the experiments. Sir Everard Home (29th vol. Philos. Trans, p. 189) and Scudamore state that they observed the escape of free carbonic acid gas from the blood during its coagulation,\u2014an observation not confirmed by others. It appears that Yogel also obtained carbonic acid from venous blood by means of the air-pump. (Schweigger\u2019s Journal, Band xi. S. 401, as quoted by Bischoff.)\nJ An Essay on the Blood, p. 108. 1824. The largest quantity of carbonic acid gas that Scudamore procured from venous blood, was half a cubic inch of gas from six ounces of blood.\n\u00a7 Magendie\u2019s Journal de Physiologie, tom. x. p. 127. 1830.\n|| Opus cit. p. 115.\n1[ Meckel\u2019s Archiv, Band ii. 1816. Nasse allowed the hydrogen to stand over blood from 24 to 48 hours.\n** Philos. Transact, vol. xlvi. p. 345. 1835.\nft Medical Gazette, for 1832 \u2014 1833, vol. xi.\np. 881.\nJJ Diss. de Respirationis Chymismo, p. 124 to 126. Enschut obtained carbonic acid by this means also from arterial blood, but in smaller quantities than from venous blood.\n\u00a7\u00a7 Experimental Essay on the Physiology of the Blood, p. 52. Edinburgh, 1837.\nIUI Commentatio de Novis quibusdam Experi-mentis Chemico-Physiologicis ad illustrandam Doc-trinam de Respiratione institutis, pp. 17, 18. Heidelberg, 1837. Bischoff also procured carbonic acid gas from arterial blood by means of the air-pump,\npp. 11, 12.\nHD Philos. Trans, vol. xxxiv. p. 506. 1823.","page":358},{"file":"p0359.txt","language":"en","ocr_en":"RESPIRATION.\n359\nand Tiedemann#, Stromeyer f, Muller and others J, failed in obtaining any carbonic acid gas from the blood by the air-pump and other means, and it was not until the publication of the important experiments of Magnus, confirmed as they have been to a certain extent by other observers, and strengthened by evidence collected both before and since on the results of the respiration of animals in hydrogen and nitrogen gases, that the existence of any free gas in the blood has been generally admitted. Bertuch and Magnus procured carbonic acid gas from human venous blood by agitating it with hydrogen.^ Magnus has not only obtained carbonic acid gas from both kinds of blood in some of the domesticated animals, but also oxygen and azote by means of the air-pump. The two latter gases were also procured from both kinds of blood by agitation with carbonic acid gas. The quantity of gases obtained from the blood by the air-pump in these experiments by Magnus amounted to J-^th, and sometimes to ith of the volume of the blood employed ; but from the difficulty of liberating the gases from the blood, he believes that this quantity forms but a small part of that actually held in solution in this fluid. In some experiments with hydrogen, the quantity of carbonic acid obtained amounted to ^th of the volume of the blood employed. The relative quantity of oxygen gas to the carbonic acid gas is greater in arterial than in venous blood. In venous blood the oxygen was as^th, and often ith, while in arterial blood it was at least as -id and sometimes \\ to the carbonic acid.|| Magnus, in a second memoir on this subject, states that he obtained the following quantities of oxygen and nitrogen from the arterial blood of two old horses, by agitating it in carbonic acid gas : \u2014\nof their constituent parts, the following results are obtained : \u2014\nCarbonic acid gas\nOxygen -Nitrogen*\nArterial blood.\tVenous blood.\nCubic centim\u00e8tres. 39*5 or 62-3 per cent. 14-7 \u201423-2 \u2014 9-2 \u201414-5 \u2014\tCubic centimetres. 47-5 or 7P6 per cent. 10-1 \u201415-3 \u2014 8-7 \u2014 1ST \u2014\nThe quantity of oxygen gas procured from the blood of calves, oxen, and horses, previously agitated with atmospheric air, was not less than 10 per cent, and not more than 12 per cent. The blood can, however, absorb a greater quantity of oxygen and nitrogen than was collected in the experiments last-mentioned, for by repeatedly shaking blood with renewed quantities of carbonic acid gas to remove the whole of the oxygen and nitrogen gases it contained, and then agitating it in measured quantities of atmospheric air, he ascertained, by again measuring the atmospheric air, that the minimum quantity of oxygen absorbed amounted to 10 per cent., and the maximum to 16 per cent. The quantity of nitrogen procured in numerous experiments on the blood of calves, oxen, and horses, previously agitated with atmospheric air, was, when reduced to the temperature of 32 Fahr, and the mean barometric pressure, from T7 to 3-3 per cent, of the volume of the blood employed. The quantity of oxygen gas which blood is capable of absorbing from the atmospheric air, is, according to Magnus, from 10 to 13 times more than water can do under the same circumstances.f The experiments\nOxygen.\tAzote.\n10'5\t2* * * \u00a701 per cent, of the volume\n10\t3 3 J of blood ernployed.il\nBy adding together the total quantity of gases collected from each kind of blood in his different experiments by means of the air-pump, and then comparing the relative proportions\n* Loc. cit.\nj- Dissertatio Liberumne Acidum Sanguine con-tinetur. G\u00f6ttingen, 1831.\nJ Two at least of these experimenters, viz. Dr. Davy and Gmelin, have since satisfied themselves that carbonic acid gas is evolved from blood under the air-pump. Dr. Davy (Philos. Transact, for 1838, p. 291) obtained it in small quantities both from venous and arterial blood, and Gmelin (Preface to Bischoff\u2019s Commentatio de Novis quibusdam Experimentis, &c.) also in small quantity from venous blood.\n\u00a7 Poggendorff\u2019s Annalen der Physik und Chemie, Band xl. S. 583. 1837.\n|| Idem opus.\n11 Poggendorff\u2019s Annalen, Band lxvi. S. 202.1845. Enschut had, previous to Magnus\u2019s experiments, obtained azote from both kinds of blood, and in greater quantity from venous than from arterial blood. Opus cit. p. 159.\n* Poggendorff\u2019s Annalen, Band lxvi. S. 189. Gay Lussac (Annales de Chimie et de Physique, 3me s\u00e9rie, tom. x. p. 1. 1844), has brought forward various objections against the inferences drawn by Magnus from his experiments. He asserts that they lead to the conclusion that more carbonic acid gas exists in arterial than in venous blood. Magnus has replied, and on the whole successfully, to these objections of Gay Lussac (Opus cit. Band lxvi). Pie contends that as the quantity of gases procured was only a part of what the blood actually contained, and as the experiments were of different duration, it must lead to error to compare, as Gay Lussac has done, the relative quantities of carbonic acid gas obtained from corresponding quantities of the two kinds of blood; and that the legitimate mode of procedure under the circumstances of the case, is to compare, as has been done in the above table, the relative quantities of the whole of the gases procured from each of the two kinds of blood.\nf Poggendorff\u2019s Annalen, Band lxvi. S. 202. In some experiments the quantity of nitrogen absorbed by the blood, when previously agitated with carbonic acid, was 6\u20185 per cent. Though these various results obtained by Magnus in his experiments have not been fully confirmed by others, indeed several experimenters, such as Enschut, Bischoff, and Dr. J. Davy, who succeeded in procuring carbonic acid gas both from venous and arterial blood, failed in obtaining decided evidence of the presence of oxygen gas, yet they appear to have been so carefully and repeatedly performed, that a belief in their general","page":359},{"file":"p0360.txt","language":"en","ocr_en":"360\nRESPIRATION.\nof Dr. J. Davy, Mitscherlich, Gmelin and Tiedemann, Enschut and Magnus, prove that venous blood can absorb considerably more than its own volume of carbonic acid gas ; and according to Mitscherlich, Gmelin and Tiedemann, and Enschut, more of this gas can be absorbed by arterial than by venous blood.*\nLehmann has endeavoured to ascertain the relative quantities of free and combined carbonic acid in the blood. In twelve experiments upon bullock\u2019s blood the average quantity of free carbonic acid in 1000 grammes ( 15433\u20190 Troy grains) of blood, was 0T32 gram. (P937 grains) of free, and 0-6759 gram. (HP431 grains) of combined carbonic acid: or, estimating these quantities by volume, in 61 \u2018250 English cubic inches of blood, there were 4\u2019271 cubic inches of free, and 21'968 cubic inches of combined carbonic acid.f\nThe results obtained on causing animals to breathe gases devoid of oxygen are in unison with those derived from direct experiment, and furnish additional evidence in proof of the existence of free gases in the blood. That a quantity of carbonic acid gas may be exhaled from the blood during the respiration of gases devoid of oxygen is proved by the experiments\naccuracy is justly almost universally entertained by physiologists. Marchand (Journal f\u00fcr praktische Chemie, Band xxxv. S. 391) is the only other chemist, as far as we are aware, who has procured oxygen gas from the blood. He ascertained, by qualitative but not by quantative analysis, that oxygen gas is contained in the venous blood of the dog.\nIt has been argued, and the objection is anticipated and examined by Magnus, that part of the carbonic acid gas obtained from the blood in the above experiments may not have existed in the free, but in the combined state in the blood. It has been proved by the experiments of Heinrich Bose (Pog-gendorff\u2019s Annalen, Band xxxiv. S. 149. 1835), and Marchand (Journal f\u00fcr praktische Chemie, Band xxxv. S. 389, 390. 1845), that when a solution of bicarbonate of soda is agitated with, or even exposed for sometime to, atmospheric air or hydrogen, it gives off part of its carbonic acid, and becomes a sesqui-carbonate ; and if heat be now applied, an additional quantity of carbonic acid is given off, and it is reduced to the state of carbonate of soda. If, therefore, bicarbonate of soda exists in the blood, part of the carbonic acid gas obtained in the experiments of Magnus and others may have been derived from this source. The exact condition of the carbonates of soda in the blood is not known : indeed their existence there has lately been called in question by Enderlin (Annalen der Chemie und Pharmacie, Band xlix. S. 317) and Liebig (idem opus, Band lvii. S. 126. 1846), but without sufficient reason, as Marchand (Journal f\u00fcr praktische Chemie, Band xxxvii. S. 321. 1846), Lehmann (idem opus, Band xl.), and Moleschott (Holl\u00e4ndische Beitr\u00e4ge, Band i. hedft ii. S. 163. 1847) have shown. '\n* Dr. J. Davy (Philos. Transact, for 1838, p. 298) has made an important observation on the absorbing capacity of the blood for carbonic acid under different circumstances. In two animals, one of which was killed by strangulation, the other by exhaustion of the air of the lungs by the air-pump, the blood of the former absorbed only 150 per cent., that of the latter 370 per cent.\nf Journal f\u00fcr praktische Chemie, von Erdmann und Marchand, Band xl. S. 133. 1847.\nof Spallanzani* and Dr. W. F. Edwardsf on the products of the respiration of snails confined in hydrogen and azote ; those of Dr. W. F. Edwards J on a fish (Cyprinus aureus) confined in water saturated with hydrogen ; those of Dr. W. F. Edwards $, Collard de Mar-tigny|j, M\u00fcller and Bergemann IT, Bischoff** and Marchand ff, on frogs confined in hydrogen or azote ; and those of Dr. W. F. Edwards JJ, upon the young of certain of the mammalia confined in hydrogen gas. The experiments of Nysten^\u00ff, in which he first exhausted the air, as far as possible, in the lungs of adult dogs, and then caused them to breathe hydrogen or azote ; and those of Sir HL Davy || ||, and of Coutanceau andNystenll, on the respiration of nitrous oxide and azote in their own persons, though not free from serious objections, are still, as far as they go, in favour of the opinion that free carbonic acid gas is contained in the blood.\nIn a former part of this article we have detailed several observations, both upon the human species and the lower animals, to prove that a quantity of azote is frequently exhaled in respiration. The experiments of Allen and Pepys***, and Nysten ff|, show that the exhalation of azote is considerably increased by breathing oxygen or hydrogen, or a mixture of these two gases, and thus afford additional evidence that free azote exists in the blood. Marchand concludes from his experiments on frogs, that when they are made to breathe pure oxygen gas, azote is evolved from the blood, and that when made to breathe pure hydrogen, both oxygen and azote are evolved from the blood.\nDifferences in the form of the red corpuscles in venous and arterial blood. \u2014 The physical\n* M\u00e9moires sur la Respiration, p. 346 to 351.\nf De l\u2019Influence des Agens Physique sur la Vie, p. 449. 1824.\nJ Opus cit. p. 447, 448.\n\u00a7 Opus cit. p. 442 to 447.\nIl Magendie\u2019s Journal de Physiologie, tom. x. p. 122 to 124.\n^[Muller\u2019s Elements of Physiology, translated by Baly, vol. i. p. 354.\n** Commentatio de No vis quibusdam Experi-mentis Chemico-Physiologicis, p. 20.\nff Journal f\u00fcr praktische Chemie, Band xxxiii. S. 154. 1844. Marchand thinks that in the experiments of those who preceded him, upon the respiration of frogs in hydrogen, that the gas employed must have contained some oxygen, as the animals lived longer than those used in his experiments where the gas was quite pure.\nOpus cit. p. 453 to 455.\n\u00a7\u00a7 Recherches de Physiologie et de Chimie Pathologiques, p. 225 to 229.\nIl II Researches, Chemical and Philosophical. Division II.\n.. 11 Coutanceau\u2019s R\u00e9vision des Nouvelles Doctrines Chimico-Physiologiques, p. 280 to 302. 1821. Coutanceau and'Nysten breathed azote alone ; and their experiments were regarded, even by Coutanceau himself, as \u201c essais bien incomplets.\u201d Opus cit. p. 301, 302.\n*** Philos. Trans. 1809, p. 404.\nttf Recherches, &c. p. 230, 231.\n\u00ce\u00ce\u00ce Opus cit.Band xxxiii. S. 154\u2014159. Band xxxv. S. 386\u2014389. Marchand does not distinctly state that he ascertained this by direct analysis of the expired gases.","page":360},{"file":"p0361.txt","language":"en","ocr_en":"RESPIRATION.\nconditions of the red corpuscles can be changed by the action of various agents, such as pure water, and solutions of certain neutral salts. By the action of the former, the corpuscles swell, become more globular, and reflect less light ; by the action of the latter, they become smaller, thinner, somewhat bent and notched, and reflect more light. These changes are apparently dependent upon endosmotic and exosmotic currents, between the fluid contents of the red corpuscles and the surrounding fluid. It has been maintained that the red corpuscles of venous and arterial blood differ in their external form, \u2014 the former approaching in their shape those acted upon by water, the latter those subjected to the action of solutions of the neutral salts ; and this change in the form of the corpuscles has been adduced as the cause of the difference in colour between arterial and venous blood. Kaltenbrunn er *, Schultz f, H. Nasse j, Scherer \u00ff, Reuter ||, Mr. Gulliver If, and Harless**, have described various differences in the external form of the red corpuscles of the two kinds of blood, as observed by them under the microscope, from which some of them infer an increase in their power of reflecting light f f ; while Burdach JJ, M\u00fcller \u00ff\u00ff, Bruch || ||, and Marchand ff, have failed in detecting by the microscope any difference in their external form in the two kinds of blood.*** Those observers who have described differences in the shape of the red corpuscles in arterial and venous blood do not quite agree in their account of these. They agree, however, in this, that the red corpuscles are\n*\tExp\u00e9rimenta circa Statum Sanguinis et Vaso-rum in Inflammatione, p. 71. 1826.\nf Das System der Circulation, S. 27. 1836.\nX Handw\u00f6rterbuch der Physiologie, von Wagner, Band i. S. 97. 1842.\n\u00a7 Zeitschrift F\u00fcr Rationelle Medizin. Herausgegeben von Henle und Pfeufer, Band i. heft ii. S. 288. 1843.\n|| Idem opus, Band iii. heft ii. S. 165. 1845.\nf Work of Hewson, printed for the Sydenham Society, note at p. 9. 1846.\n*\t* Monographie \u00fcber den Einfluss der Gase auf die Porm der Blutk\u00f6rperchen, vonRana temporaria. Erlangen, 1846.\ntt We have not included, for obvious reasons, among these authorities in favour of there being a difference in the shape of the red corpuscles in the two kinds of blood, those authors who, like Henle and Mulder, have adopted this view without stating that they had personally investigated by the microscope the point at issue.\n\u00ee\u00ee Traite de Physiologie, &c. traduit par Jourdan, tom. vi. p. 135, 136. 1837.\n\u00a7\u00a7 Elements of Physiology, translated by Balv, vol. i. p. 346. 1840.\nIUI Zeitschrift, &c. Von Henle und Pfeufer, Band i. heft iii. S. 440. 1844 ; Band v. heft iii. S. 440. 1847.\nf f Journal f\u00fcr praktische Chemie, Band xxxviii. S. 279. 1846.\n*** Dr. G. 0. Rees (Med. Gazette, Session 1844-5, p. 840) maintains that the structure of the red particles prevents the possibility of their assuming any other form than the biconcave in a fluid of the specific gravity of serum, whether exposed to air or not ; but this statement appears to be founded upon the presumed effects of the endosmotic and exosmotic conditions of the red corpuscles, and not upon any examination by the microscope of the effects of gases upon these bodies.\n361\nmore turgid and less clear in venous than in arterial blood. Scherer describes the red corpuscles in arterial blood as biconcave, and those in venous blood as biconvex and decidedly swollen. Mr. Gulliver states that in all his experiments \u201c the red corpuscles were reduced in size, both in breadth and thickness, by neutral salts, and in a less degree by sugar and oxygen ; while the first effect of water and of carbonic acid was to swell the corpuscles and make them more globular.\u201d Nasse says that the red corpuscles of the arterial blood in the mammalia, on the contact of carbonic acid gas, become muddy in the middle, the ring formed by the colouring matter becomes broader, they become darker and somewhat thicker, at least on one side, and they adhere closer together. Harlass gives measurements of the corpuscles of the blood of the frog, when brought into contact with oxygen and carbonic acid, to show that they become somewhat broader and thicker when exposed to the action of the latter gas. He also states that while the corpuscles in the former are finely granulated on the external surface, those in the latter are smooth.\nTheory of respiration. \u2014 The actions between the blood and the atmospheric air in the performance of the function of respiration are regulated entirely by chemico-physical laws. No doubt the blood and air are conveyed to and from the lungs through the instrumentality of the vital properties of the nervous and muscular tissues, but the changes they there undergo do not appear to be influenced by vitality. When venous blood and atmospheric air are brought into contact out of the body, the same actions apparently occur as in the lungs during life, viz., the atmospheric air loses part of its oxygen, acquires in its place a quantity of carbonic acid gas, and the blood assumes the arterial hue. The distribution of the blood in innumerable minute streamlets upon the surface of the air-cells, filled with atmospheric air, affords much more advantageous means than can be obtained in experiments out of the body, for facilitating the mutual actions of the blood and atmospheric air. From the known rapidity with which gases permeate both living and dead animal membranes, the moist delicate membranes that intervene between the blood contained in the capillaries of the lungs, and the atmospheric air in the air-cells, will readily permit the endosmose of a portion of the atmospheric air, and the exosmose of a portion of the gases held in solution in the blood.\nThe rest of our remarks on the theory of respiration maybe arranged under three heads : viz. 1st, the manner in which the air in the upper and in the lower parts of the respiratory apparatus is intermixed ; 2dly, the nature of the immediate actions between the blood and atmospheric air in the lungs, in which a quantity of carbonic acid gas appears in the expired, and a quantity of oxygen disappears from the inspired air ; 3dly, the nature of the changes the blood undergoes in passing from the venous to the arterial condition.","page":361},{"file":"p0362.txt","language":"en","ocr_en":"362\tRESPIRATION.\nOn the manner in which the air in the upper and lower parts of the respiratory apparatus becomes intermixed.\u2014The respiratory qualities of the other parts of the inner surface of the air-passages must be very feeble when compared with the membrane of the air-cells of the lungs ; and there can be no doubt that almost all the carbonic acid present in the expired air is derived from the blood circulating in the capillary blood-vessels of the air-cells ; and that this evolution of carbonic acid gas is continuous, going on during expiration as well as during inspiration. As a portion only of the atmospheric air, probably not much more than a fourth or a fifth part, is renewed at each ordinary respiratory movement when the body is in a state of rest, the air expelled during expiration will chiefly consist of that occupying the larynx, trachea, and the larger bronchial tubes ; so in the same manner, the air drawn in by inspiration will chiefly occupy the same parts of the respiratory apparatus. It is well known that the air expelled in the first part of an expiration contains less carbonic acid than that expelled towards its close ; thus the air in the deeper parts of the respiratory apparatus must be richer in carbonic acid and poorer in oxygen than that in the upper parts. The amount of intermixture of the gases in the different parts of the respiratory apparatus effected by the muscular movements of the chest would, in all probability, be too imperfect for the proper art\u00e9rialisation of the blood, were this not aided by the well-known tendency of gases to diffuse themselves through each other. As the air in the air-cells differs from that in the higher parts of the respiratory apparatus in containing more carbonic acid and less oxygen, the nitrogen being nearly the same in both, this diffusion of gases is probably chiefly confined to the two former. From the oxygen being of lighter specific gravity than the carbonic acid gas, the descending current of oxygen gas will exceed the ascending current of carbonic acid, and 81 parts of carbonic acid will be replaced by 95 of oxygen, for according to the law regulating the diffusion-volumes of gases under such circumstances, established by Graham, in the case of each gas this is inversely proportional to the square root of its density.* *\nOn the nature of the actions between the blood and the atmospheric air in the lungs, by which a quantity of oxygen is removed from the inspired air, and a quantity of carbonic acid gas added to the expired air.\u2014Four views have been maintained on this point.\u2014 ]. That of Lavoisier, La Place, and others; that the oxygen which disappears from the inspired air unites directly in the lungs with hydrocarbon furnished by the venous blood, and forms the carbonic acid gas and watery vapour that escape along with the expired air.'j-\n* Edinburgh Transactions of Royal Society, vol. xii. p.573. 1834.\nf Seguin and Lavoisier \u201c Sur la Transpiration des Animaux,\u201d in M\u00e9moires de l\u2019Acad\u00e9mie des\n2.\tThat of La Grange and Hassenfratz; that free carbonic acid gas is present in a state of solution in the venous blood before it arrives at the lungs, where this gas is exhaled ; that nearly the whole of the oxygen gas abstracted from the inspired air is absorbed at the lungs, and held in solution by the arterial blood ; and that the combination of the oxygen with the carbon and formation of carbonic acid chiefly take place when the blood is passing through the capillaries of the systemic circulation.*\n3.\tThat the oxygen that disappears from the inspired air enters into chemical combination with one or more of the constituent parts of the blood in its course through the lungs, that in the passage of the blood through the capillaries of the systemic circulation this oxygen leaves the substance or substances to which-it had united itself, and combines with carbon to form carbonic acid, or with carbon and hydrogen to form carbonic acid and water, and that the carbonic acid thus formed does not combine chemically with any of the constituent parts of the venous blood, but is held in solution by it, and is evolved while passing through the capillaries of the lungs.\n4.\tThat not only the oxygen that disappears from the inspired air is united chemically in the arterial blood, but also the carbonic acid formed during its circulation through the systemic capillaries enters into chemical combination with some one of the constituent parts of the venous blood ; that the combination thus formed is decomposed in the pulmonic capillaries by the agency of the absorbed oxygen, and the carbonic acid thus set free is evolved and escapes in the expired air.\nThe first view, viz. that the carbonic acid that appears in the expired air is formed in the lungs by the combination of part of the oxygen of the inspired air with the carbon of the venous blood, must now be regarded as untenable. The existence of free gases in the blood, the evolution of carbonic acid from the blood at the lungs in animals made to breathe gases devoid of oxygen, the small increase of\nSciences for 1790, p. 601. It is still maintained by some chemists and physiologists, who appear to regard the function of respiration simply as a process of combustion, but who do not uphold the opinion that this combustion takes place in the lungs and that the watery vapour in the expired air is immediately derived from this source, that a part of the oxygen that disappears from the inspired air unites with hydrogen to form water. No satisfactory evidence is offered in support of this opinion, and in the present state of our knowledge it must be regarded as a mere conjecture.\n* This doctrine, as propounded by Hassenfratz (Annales de Chimie, tom. ix. p. 261. 1791), which has received various modifications since his time, was based on the view that the purple colour of the venous blood is the result of the combination of oxygen with the carbon and hydrogen of the blood, while the scarlet colour of arterial blood is caused by the solution of oxygen gas in it, and consequently there can be little combination of the carbon and hydrogen of the blood -with the atmospheric air in the lungs.","page":362},{"file":"p0363.txt","language":"en","ocr_en":"RESPIRATION.\t363\ntemperature the blood acquires in its change from the venous to the arterial condition *, and the result of observations made upon the blood out of the body, when subjected to alternate applications of oxygen and carbonic acid gas, are all opposed to the supposition that the formation of carbonic acid gas takes place to any great extent in the lungs. The existence of a quantity of free carbonic acid in the venous blood, more than sufficient to furnish the whole of this gas thrown off at the lungs, and the avowedly conjectural explanation of the manner in which the carbonic acid is combined and the agency by which its combinations are decomposed in the lungs, given by those who advocate this view, justify the adoption of the opinion that the carbonic acid gas evolved at the lungs exists in a free state in the venous blood before it reaches the lungs.\nAn interchange, therefore, takes place between the air in the cells of the lungs and the biood in the pulmonic capillaries, the latter receiving oxygen and giving up part of the free carbonic acid held by it in solution. These gases, from their solubility, readily permeate the thin moist membranes interposed between the blood and the atmospheric air contained in the cells of the lungs. We have already mentioned that Valentin and Brunner have concluded from their experiments that this interchange of oxygen and carbonic acid gas is regulated by the law of the diffusion of gases established by Graham ; but besides the objections that may be urged against this view, drawn from the considerable diversity in the relative proportions of these gases interchanged during respiration as ascertained by different experimenters, the conditions under which the two gases are placed in respiration are very different from those in the experiments instituted by Graham.f In respiration the gases are separated by moist animal membranes, and one of these, viz. the carbonic\n* Dr. J. Davy ascertained (Lond. Philos. Trans, for 1838, p. 298) that oxygen gas shaken with venous blood out of the body raised the temperature of the latter from 1\u00b0 to 2\u00b0 Fahr. Marchand (Journal f\u00fcr praktische Chemie, Band xxxv. S. 400) adduces reasons for believing that this increase in temperature arose from the mere absorption of the gas, and not from any chemical action between it and the blood.\nf Graham\u2019s first experiments, from which he deduced his law that \u201c the diffusive velocities of different gases are inversely as the square root of their densities,\u201d were made by interposing a porous septum of stucco between the gases experimented upon and the external air. The equivalent diffusion-volumes of oxygen and carbonic acid calculated according to this theory, with which the experimental results closely agree, are\u2014air being equal to 1, oxygen 0\u20189487, and carbonic acid 0-8091. (Transactions of Royal Society of Edinburgh, vol. xii. p. 222. 1834.) In some later experiments Mr. Graham ascertained that this law also held when gases pass through minute apertures in a thin plate into a vacuum, while, on the other hand, the discharge of the same gases through tubes into a vacuum has no uniform relation to the density of the gases. (Philosophical Transactions of London for 1846, p. 373.)\nacid, is held in solution in a fluid subjected to an increased pressure caused by the action of the heart.*\nWe are not, in the present state of our knowledge, in a condition to form any thing like an accurate estimate of the various circumstances which regulate this interchange between the oxygen of the air and the carbonic acid gas of the blood, but it is obvious that it will be affected in a most important manner by the relative proportion of these gases in the air contained in the air-cells of the lungs and in the blood, and by the quantities of atmospheric air and blood transmitted through the respiratory apparatus.\nWe have seen, from the experiments of Vierordt, that when the air is rapidly renewed in the lungs, though the percentage of carbonic acid in the expired air is diminished, yet the total amount of this gas thrown off from the lungs within a given time is proportionally increased ; while, on the other hand, when the respirations are diminished below the natural standard, though the percentage of carbonic acid in the expired air is increased, yet the total quantity thrown off from the lungs in a given time is proportionally diminished. When the atmospheric air in the lungs is rapidly renewed by an increased frequency of the respiratoi\u2019y movement, the diffusion of the oxygen in the higher, and of the carbonic acid in the deeper, parts of the air tubes will proceed more rapidly, and the air in the deeper parts or in the air-cells will contain a less percentage of carbonic acid, and a greater percentage of oxygen, than when the respirations are carried on with the usual frequency and force. This diminution of the usual quantity of carbonic acid gas and increase of oxygen in the deeper parts of the lungs will accelerate the interchange between the oxygen of the air and the carbonic acid of the blood, provided the blood holds its normal amount of free gases in solution, and a larger quantity than usual of carbonic acid will be separated from the blood at\n* The passage of gases through moist membranes is not simple diffusion, as it is influenced by the solubility of these gases in the fluids of the membranes. In the case of respiration it will also probably be affected by the attractive force of the constituents of the blood for the gases. The relative rapidity of the passage of different gases through membranous septa, as observed in the experiments of Dr. Faust and of Mr. Mitchell (American Journal of the Medical Sciences, Nov. 1830), and by other experimenters, is not in accordance with the law of the diffusion of gases, as determined from experiments upon their diffusive velocities through porous septa into the atmospheric air, and through minute apertures in a thin plate into a vacuum. When a bladder filled with oxygen gas is introduced into a vessel full of carbonic acid gas, the latter passes so much more rapidly through the coats of the bladder than the former, that the bladder becomes gradually distended, and at last may burst. In these last experiments, equally as in those of Graham, the conditions under which the diffusion of the gases occurs, are not the same as those in respiration ; and we find the carbonic acid gas passing in greater quantity through the organic membranes than the oxygen,\u2014 the reverse of what takes place in respiration.","page":363},{"file":"p0364.txt","language":"en","ocr_en":"364\tRESPIRATION.\nthe lungs, and carried out in the expired air. If, then, we add an increased flow of blood through the capillaries of the lungs to an increased frequency of the respiratory movements, as occurs in exercise, the interchange between the oxygen of the air and the free carbonic acid of the blood will he carried on with greater activity. When, on the other hand, the air is renewed in the lungs less frequently than usual, as happens when the respiratory movements are diminished in number and in extent, the air in the deeper parts of the lungs will contain less oxygen and more carbonic acid than usual, and the interchange between the oxygen of the atmospheric air and the free carbonic acid of the blood will proceed more slowly. When the respirations are reduced to about one half of their normal frequency, as occurs in the course of some diseases, and after division of the vagi nerves, the carbonic acid gas gradually accumulates in the blood, less oxygen is absorbed, and the individual generally sooner or later dies of asphyxia. When the quantity of carbonic acid gas in the air-cells reaches a certain amount, the evolution of this gas from the blood will cease ; and when this is carried still farther, there will be an absorption of a part of the carbonic acid gas by the blood.\nThe interchange between the nitrogen and the other gases at the lungs is very small in the normal condition of the respiration, but there is every reason to believe that this is regulated by circumstances similar to those which determine the interchange of the oxygen and carbonic acid. The nitrogen is much less soluble in the blood than the oxygen and carbonic acid, and we presume that its power of permeating moist animal memoranes is much inferior to these gases, and that the smaller quantity of it held in solution in the blood may be in this manner explained. We have already pointed out that, in the experiments made to determine whether nitrogen is absorbed or exhaled at the lungs, opposite results have been obtained, but that the evidence preponderates in favour of the opinion that a small quantity of this gas is evolved from the blood during respiration. By an alteration of the usual relation between the quantities of nitrogen present in the air and in a free state in the blood, the evolution of nitrogen from the blood may be increased or suspended, or it may be absorbed by the blood instead of being evolved by it. In a previous part of this article we have referred to experiments which prove that when animals breathe oxygen or hydrogen gases, or a mixture of both, azote is evolved in greater quantity than usual from the blood in the lungs; and that when they breathe azote alone, part of this gas is absorbed at the lungs.\nThe exact condition in which the whole of the oxygen absorbed at the lungs exists in the blood, notwithstanding the light thrown upon this point by recent researches, is still not free from considerable difficulties. Previous to the experiments of Magnus upon the\ngases of the blood, already referred to, the opinion of Le Grange and Hassenfratz, that the greater part of the oxygen gas absorbed at the lungs is dissolved in the blood and carried along with it in that condition to the systemic capillaries, was considered untenable by many celebrated physiologists, the more especially as the attempts to detect free oxygen in the arterial blood had failed in all the more trust-worthy experiments. Different opinions as to the kind of chemical combination formed by the oxygen in the arterial blood have been entertained by those who believe that the portion of this gas that disappears from the inpired air does not unite with carbon in the lungs to form carbonic acid, and that little or none of it is simply dissolved in the arterial blood. In the greater number of these hypotheses, however, the oxygen is supposed to unite itself in whole or in part to the red corpuscles, and especially to the iron contained in these: and as the exact state in which the metal exists in the red corpuscles is still undetermined, this has given rise to very different notions regarding the changes effected upon it by the oxygen. According to other views, the oxygen in whole or in part is united chemically to some of the other constituent parts of the arterial blood, and from these it is again separated in passing through the systemic capillaries, and unites with carbon to form carbonic acid.*\n* We shall here very shortly notice a few of the more recent theories of respiration, which proceed on the supposition that the oxygen abstracted from the inspired air is combined, in whole or in part, with some of the constituents of the arterial blood. Gme-lin, Tiedemann, and Mitscherlich (Zeitschrift f\u00fcr Physiologie, Band v.) supposed that the oxygen absorbed at the lungs partly unites with carbon and hydrogen to form carbonic acid and water which are there exhaled, and partly -with organic substances in the blood to form acetic and lactic acids : that these acids decompose some of the carbonates of soda brought to the lungs in the venous blood, and that the carbonic acid thus set free is also exhaled. The arterial blood in its course through the tissues, more especially those of the kidneys and skin, loses part of its acetic and lactic acids ; and the soda with which they were combined, being set free, unites with the carbonic acid formed during the process of nutrition, and these carbonates are again decomposed in the lungs in the manner described. Dumas (Statique Chimique des Etres Organises, pp. 43, 44, 3me \u00e9dit.) believes that the absorbed oxygen combines with certain matters of the blood and forms lactic acid, the lactic acid combines with soda to form lactate of soda, and this latter salt, by a real combustion, is converted into carbonate of soda, which is decomposed in its turn in the lungs by a fresh portion of lactic acid. Liebig (Organic Chemistry of Physiology and Pathology, edited by Gregory, p. 265. 1841) supposes that carbonate of protoxide of iron exists in the red corpuscles of venous blood, and that in its passage through the lungs, a large portion of the absorbed oxygen unites with it, forms hydrated peroxide of iron, and sets the carbonic acid free. Mulder (The Chemistry of Vegetable and Animal Physiology, translated by Fromberg, Part II. p. 337) affirms that an alternate change into carbonate of the protoxide of iron and peroxide of iron in respiration is impossible, and maintains that the absorbed oxygen combines with the proteine compounds of the blood and forms oxy-proteine, which being conveyed by the","page":364},{"file":"p0365.txt","language":"en","ocr_en":"RESPIRATION.\n365\nThe presence of a larger quantity of free oxygen gas in the arterial blood than what is sufficient to form the carbonic acid gas evolved at the lungs, amounting in some cases to rather more than 10 per cent, of the volume of the blood in the experiments of Magnus, naturally leads to the conclusion that the greater part, at least, of the absorbed oxygen is not chemically combined in the arterial blood, and is simply held in solution by it. We are not, however, quite prepared to concur in the opinion of Magnus, that the ivhole of the absorbed oxygen is held in solution in the arterial blood, and that an interchange between part of the free carbonic acid of the venous blood, and part of the oxygen of the atmospheric air, embraces the entire changes in the blood as it passes from the venous to the arterial condition : for, if the opinion be correct that the elaboration of the materials of the chyle into blood is completed in the lungs, and that certain marked differences in the fibrin of the two kinds of blood, noticed above, really exist, something more than this is probably necessary. Though the experiments of Marchand appear to prove that the absorbed oxygen does not enter into any chemical combination with the constituent parts of the arterial blood in the lungs, by which carbonic acid gas is formed ; yet, while the greater part of the absorbed gas is held in solution in the arterial blood, a small portion of it may enter into chemical combination in a manner hitherto not definitely ascertained.* *\nIt is almost universally believed that the free carbonic acid gas in the blood is formed by the combination of the absorbed oxygen with carbon in the blood, chiefly if not en-\narterial blood to the capillaries is decomposed during the nutritive processes, and carbonic acid is formed and held in solution in the blood.\n[Dr. G. 0. Rees has lately put forward the following ingenious theory of respiration. He finds by analysis that the corpuscles of venous blood contain fatty matter in combination with phosphorus, which does not exist in arterial blood, or, at most, is found in it only in very small quantity. In respiration the oxygen of the inspired air unites with this phosphorus and fatty matter, and a combustion of it takes place, of which the products are water and carbonic acid, from the union of the oxygen with the elements of the fatty matter, and phosphoric acid, from the union of the oxygen with the phosphorus. The carbonic acid and water are exhaled, and appear in the expired air ; the phosphoric acid attracts the soda of the liquor sanguinis from its combination with albumen and lactic acid, and thus forms a tribasic phosphate of soda, a salt which possesses in a marked degree the property of giving a bright colour to h\u00e6matosine. See Dr. Rees\u2019 paper in the Lond. Edin. and Dubl. Phil. Mag. for July, 1848. \u2014 Ed.]\n* Marchand ( Journal f\u00fcr praktische Chemie, Band xxxv. S. 385. 1845) in his experiments found that oxygen gas does not unite with fibrin to form carbonic acid until it has been exposed to its action for some days, in fact not until it is passing into a state of putrefaction; and that, on subjecting to a continuous current of oxygen gas, the red corpuscles, and beaten venous blood, after all the free carbonic acid held in solution had been carefully separated by the air-pump and agitation with hydrogen, no carbonic acid gas was evolved. These experiments invalidate\ntirely in the course of its circulation through the systemic capillaries ; but this opinion, however plausible it may appear, and though it apparently accounts for the evolution of animal caloric in a satisfactory manner, does not rest upon any direct evidence. There are no facts that militate against the existence of such a combination, and there can be no doubt that in the present state of our knowledge it affords the readiest and most complete interpretation of the phenomena referred to it, but still it is quite possible that the carbonic acid may be formed during the process of nutrition differently from what is generally supposed.\nCause of the change of colour in the blood. \u2014 The manner in which the changes of colour in the blood is effected as it passes through the pulmonic and systemic capillary vessels, has not yet been satisfactorily determined. It seems now to be pretty generally admitted that the h\u00e6matosine or colouring matter of the blood is enclosed within the enveloping membrane of the red corpuscles ; that this h\u00e6matosine, though it may be combined with iron, does not derive its colour from the presence of this metal ; and that all attempts to explain the change in the colour of the blood in the lungs by the formation of certain oxides and salts of iron must be abandoned. It is well known that various substances, besides oxygen gas, can impart a bright red colour to venous blood when mixed with it, and without being attended with any evolution of carbonic acid gas. The best known of these are solutions of the sulphate of soda, nitrate of potass, phosphate of soda, carbonate of soda, carbonate of potass, and sugar.\nThe opinion of Stevens *, that the change from the venous to the arterial hue in the blood is to be attributed to the actions of the salts dissolved in the blood upon the h\u00e6matosine, after the removal of the free carbonic acid of the venous blood through the attractive force of the oxygen of the atmospheric air, has not been confirmed by subsequent researches. It has been ascertained that the removal of carbonic acid from venous blood, by means of the air-pump f, or by agitation\nthe inferences in favour of the opinion, that the oxygen absorbed at the lungs partly enters into combination with the constituents of the blood in the lungs and forms or liberates carbonic acid gas, drawn from the experiments of Scherer (Annalen der Chemie und Pharmacie, Band xl. 1841) upon the action of oxygen gas upon fibrin, and those of Berzelius (Lehrbuch der Chemie, Band iv. S. 94. 1831), and Maack (De Ratione qu\u00e6 Colorem Sanguinis inter, &c., p. 35. Kili\u00e6 1834) upon the greater absorbing power for oxygen of the colouring matter of the blood over the serum. Mulder (Holl\u00e4ndische Beitr\u00e4ge, &c. Band i. heft i. B. 20. 1846) adduces various arguments to show that the experiments of Magnus, and they apply equally to those of Marchand, by no means prove that a part of the oxygen absorbed at the lungs does not enter into chemical combination with the constituents of the blood before it reaches the capillaries of the systemic circulation.\n* London Philos. Transact, vol. xlvi. p. 345. 1835.\nj- Dr. J. Davy and others.","page":365},{"file":"p0366.txt","language":"en","ocr_en":"366\nRESPIRATION.\nwith hydrogen gas * * * \u00a7 and the addition of a saline solution, of the same strength as that existing in the blood f, will not impart to it the arterial hue, if oxygen gas be not at the same time present. The oxygen gas, therefore, acts directly, and not indirectly by removing the carbonic acid, in changing the colour of the blood; but as a small quantity only of this gas is sufficient, when the salts are present in their usual quantity, to produce this effect J, the action of the oxygen, in changing the colour of the blood in respiration, will be aided by the presence of the salts.\nIn the present state of our knowledge, there is some difficulty in deciding whether the reddening of the blood by the absorbed oxygen be entirely a physical action, or whether it be partly physical and partly chemical, seeing that several accurate observers, who have recently investigated this point, have arrived at very different conclusions.\nThe opinion, first promulgated by Dr. Wells \u00ff, that the change from the venous to the arterial hue arises from an increased reflection of light in the red particles, caused by the presence of the absorbed oxygen, and without any chemical change upon the h\u00e6ma-tosine, has of late obtained several supporters. Those who have adopted this view do not, however, agree in their explanation of the manner in which this increased reflection of light is effected; some maintaining that it arises from an alteration in the form of the red corpuscles, and that this change consists in the biconvex corpuscles of the venous blood, becoming biconcave in the arterial blood || ; while others believe that the action of the oxygen on the blood is analogous to that of the nitrous oxide on the solutions of\n* Bischoff, Dr. Maitland, Nasse, and Marchand.\nt Gregory and Irving (vide London Medical Gazette, vol. xiii. p. 814. 1834). Nasse (Wagner\u2019s Handw\u00f6rterbuch, &c., Band i. S. 182) affirms that even concentrated solutions of muriate of soda, nitrate of potassa, and carbonate of potass, cannot impart the true arterial hue to venous blood, without the presence of a small quantity of oxygen; and that when Stevens saw the blood redden under the air-pump, there must have been sufficient oxygen still present in the rarefied air to act on it with the aid of the salts.\n\u00ce Nasse (opus cit. p. 182). He also infers from his experiments that oxygen can redden the blood without the presence of salts (p. 187).\n\u00a7 London Philos. Transact, for 1797, p. 41G.\n|| Scherer, Beuter, and Gulliver. Mulder (The Chemistry of Animal and Yegetable Physiology, p. 341, 342.) also contends that the arterial hue depends upon the red particles assuming the biconcave form and reflecting more light, but he gives a very different explanation of the cause of the change in the form of the red particles from the other supporters of this view. According to Mulder, part of the oxygen absorbed unites with some of the proteine compounds in the blood in the lungs, and forms oxy-proteine, and this furnishes a thin envelope to the red corpuscles, and by its contraction causes them to assume the biconcave form. This opinion is supported neither by direct observation nor by experiment. Marchand (Journal f\u00fcr praktische Chemie, Band xxxviii. \u00a7 276, 277) and Dumas (Comptes Rendus for 1846, tom. xxii. p. 900) after separa-\nthe salts of iron, changing their colour without entering into chemical union with them.* We may, in the meantime, conclude that the change in the blood from the venous to the arterial hue in the lungs, is a physical and not a chemical action ; and that though there is pretty strong evidence in favour of the opinion that this physical change consists in an alteration of the form of the red corpuscles, yet it is not free from doubt.\nThe various systematic works on Physiology are not included in the following Bibliography of Respiration.\nBibliography.\u2014Mayow, Tractus Duo, quorum prior agit de Respiratione : alter de Raehitide, Oxon. 1669. Lower, Tractus de Corde, &c. Caput iii. De Colore Sanguinis, Lugduni, 1722. Priestley, Observations on Respiration and the Uses of the Blood, in Philos. Transact, of London for 1776. Lavoisier, Experiences sur la Respiration des Animaux, et sur les Changemens qui arrivent \u00e0 l\u2019Air en passant par leur Poumons, in M\u00e9moires de l\u2019Acad\u00e9mie Royale des Sciences de Paris, for 1777, published in 1780. Lavoisier and La Place, M\u00e9moire sur la Chaleur. Article IY. De la Combustion et de la Respiration, in M\u00e9m. de l\u2019Acad. Roy. des Sciences for 1780, published in 1784. Crawford, Experiments and Observations on Animal Heat, &c., London, 1788. Goodwyn, On the Connexion of Life with Respiration, &c., London, 1788. Lavoisier and Seguin, Premier M\u00e9moire sur la Respiration des Animaux, in M\u00e9m. de l\u2019Acad. Roy. des Sciences for 1789; and Sur la Transpiration des Animaux, in M\u00e9m. de l\u2019Acad. Roy. des Sciences for 1790. Men-zies, Tent. Inaug. de Respiratione, Edinburgh, 1790. Hassenfratz, M\u00e9moire sur la Combinaison de l\u2019Oxi-g\u00e8ne avec le Carbone et l\u2019Hydrog\u00e8ne du Sang, sur la Dissolution de l\u2019Oxig\u00e8ne dans le Sang, et sur la Mani\u00e8re dont le Calorique se d\u00e9gage, in Annales de Chimie, torn. ix. 1791. Coleman, On natural and suspended Respiration, London, 1791. Vauquelin, Observations Chimiques et Physiologiques sur la Respiration des Insects et des Yers, in Annales de Chimie, torn. xii. 1792. Wells, Observations and Experiments on the Colour of the Blood, in Philos. Transact, of London for 1797. Sir Humphry Davy, Researches Chemical and Philosophical, &c., London, 1800. Spallanzani, M\u00e9moires sur la Respiration, traduits par Senebier, Gen\u00e8ve, 1803. Bostock, On Respiration, Liverpool, 1804. Henderson, Experiments and Observations on the Changes which the Air of the Atmosphere undergoes by Respiration, particularly with regard to the Absorption of Nitrogen, in Nicholson\u2019s Journal of Natural Philosophy, vol. viii. 1804. Brande, A concise Yiew of the Theory of Respiration, in Nicholson\u2019s Journal, vol. xi. 1805. Pfaff, New Experiments on the Respiration of Atmospheric Air, &c., in Nicholson\u2019s Journal, vol. xii. 1805. Ellis, On the Changes of Atmospheric Air in Respiration and Vegetation, parts i. and ii. Edinburgh, 1807\u20141811. Allen and Pepys, On the Changes produced in Atmospheric Air and Oxygen by Respiration, in Philos. Transact, of London for 1808 : and, On Respiration, in Philos. Trans, for 1809. Berthollet, Sur les Changemens que\nting the red corpuscles from the other constituents of the blood, and washing them in a solution of sulphate of soda, found that they still changed from the venous to the arterial colour on the addition of oxygen. Dumas concludes, that neither the presence of albumen nor fibrin is necessary to enable oxygen to redden venous blood ; and Marchand, after a careful experimental investigation, affirms that the supposition that the changes of colour in the blood are from a chemical action, is attended with insuperable difficulties (opus cit. Band xxxviii. S. 278).\n* Magnus and Marchand.","page":366},{"file":"p0367.txt","language":"en","ocr_en":"RESPIRATION.\n367\nla Respiration produit dans l\u2019Air, in M\u00e9moires de la Soci\u00e9t\u00e9 d\u2019Arcueil, tom. ii. 1809. Proven\u00e7al and Humboldt, Recherches sur la Respiration des Poissons, in M\u00e9m. de la Soc. d\u2019Arcueil, tom. ii. 1809. Nysten, Recherches de Physiologie et de Chimie Pathologiques, Paris, 1811. Legallois, Exp\u00e9riences sur le Principe de la Vie, Paris, 1812 ; and M\u00e9moire sur la Chaleur Animale, in Annales de Chimie et de Physique, torn. iv. p. 1, and p. 113. 1817. Dalton, On Respiration and Animal Heat, in Memoirs of the Literary and Philosophical Society of Manchester, second series, vol. ii. 1813. Prout, Observations on the Quantity of Carbonic Acid Gas emitted from the Lungs during Respiration at different Times and under different Circumstances, in Thomson\u2019s Annals of Philosophy, vol. ii. 1813, and vol. iv. 1814. Nasse, Untersuchungen \u00fcber das Athmen, in Meckel\u2019s Archiv fur Anatomie und Physiologie, Bandii. 1816. Coutanceau, Revision de Nouvelles Doctrines Chi-mico-Physiologiques, &c., Paris, 1821. Dulong, De la Chaleur Animale, in Magendie\u2019s Journal de Physiologie, tom. iii. 1823. W. T. Edwards, De l\u2019Influence des Agens Physiques sur la Yie, Paris, 1824. Despretz, Recherches Exp\u00e9rimentales sur les Causes de la Chaleur Animale, in Annales de Chimie et de Physique, tom. xxvi. 1824; also in Magendie\u2019s Journal, tom. iv. 1824. Scudamore, An Essay on the Blood, London, 1824. Herbst, Ueber die Capa-cit\u00e4t der Lungen f\u00fcr Luft in gesunden und kranken Zustande, in Meckel\u2019s Archiv, Band xiii. 1828. Collard de Martigny, Recherches Exp\u00e9rimentales et Critiques sur l\u2019Absorption et sur l\u2019Exhalation Respiratoires, in Magendie\u2019s Journal de Physiologie, tom. x. p. 111. 1830 ; also, Recherches Exp\u00e9rimentales sur l\u2019Exhalation Gazeuse de la Peau, at p. 162 of the same volume. Apjohn, Experiments relative to the Carbonic Acid of the expired Air in Health and in Disease, in Dublin Hospital Reports, vol. v. 1830. G. R. and R. C. Treviranus, Versuche \u00fcber das Athmenholen der niedern Thiere, in Zeitschrift fur Physiologie, von Tiedemann und Treviranus, vierter Band. 1831. Christison, On the Mutual Action of Blood and Atmospheric Air, in Edinburgh Med. and Surg. Journal, vol. xxxv. 1831. Stevens, Observations on the Healthy and Diseased States of the Blood, London, 1832 ; also, Observations on the Theory of Respiration, in London Medical Gazette, vol. xiv. 1834 ; and Philos. Trans, of London, vol. xlvi. 1835. Hoffman, Observations and Experiments on the Blood, in Medical Gazette for 1832, 1833, vol. xi. Reid- Clanny, Experiments on the Blood, in Lancet for 3d Nov. 1832, also on 13th April and 15th May, 1833. Gmelin, Tiedemann, and Mitscherlich, Versuche \u00fcber das Blut, in Zeitschrift fur Physiologie, Band v. 1833. Maack, De Ratione qu\u00e6 Colorem Sanguinis inter et Respirationis Func-tionem intercedit, Kili\u00e6, 1834. Graham, On the Law of the Diffusion of Gases, in Trans, of Royal Society of Edinburgh, vol. xii. 1834 : On the Motion of Gases, in Philos. Transact, of London for 1846. H. Nasse, Das Blut Physiologisch und Pathologisch untersucht, Bonn, 1836 : also, article \u201cBlut\u201d in Wagner\u2019s Handw\u00f6rterbuch der Physiologie, 1845. Enschut, Dissertatio Physiologico-Medica de Respirationis Chymismo. Trajecti ad Rhenum, 1836. Bischoff, Commentatio de Novis quibusdam Experiments Chemico-Physiologicis ad illustrandam Doctrinam de Respiratione instituts. Heidelberg\u00e6, 1837. Magnus, Ueber die in Blute enthalten Gase, Sauerstoff, Stichstoff, und Kolens\u00e4ure, in Poggen-dorff\u2019s Annalen der Physik und Chemie, Band xl. 1837 : Ueber des Absorptions verm\u00f6gen des Blute fur Sauerstoff, in Poggendorff\u2019s Annalen, Band lxvi. 1845. Maitland, Experimental Essay on the Blood, Edinburgh, 1837. Becquerel and Breschet, Recherches Exp\u00e9rimentales Physico-Physiologiques sur la Temp\u00e9rature des Tissues et des Liquides Animaux, in Annales des Sciences Naturelles, 2me s\u00e9rie, tom. vii. 1837. Dr. John Davy, An Account of some Experiments on the Blood in connexion with the Theory of Respiration, in Philos. Transact, of London for 1838 : Researches, Physiological and Ana-\ntomical, in 2 vols. London. 1839. Coathupe, Experiments upon the Products of Respiration at different Periods of the Day, in London, Edinburgh, and Dublin Philosophical Magazine, vol. xiv. 1839. M\u2018Gregor, Experiments on Carbonic Acid thrown off from the Lungs, in p. 87 of Transactions of the Sections in the Report of the British Scientific As \u2022 sociation for 1840. Leblanc, Recherches sur la Composition de l\u2019Air confin\u00e9, in Annales de Chim. et de Phys. tom. v. 1842. Mandl, M\u00e9moire sur les Alt\u00e9rations qu\u2019\u00e9prouve le Sang pendant la Respiration, in Archiv. G\u00e9n\u00e9r. de M\u00e9d. 3me s\u00e9rie, tom. xiii.\n1842.\tBeau and Maissiat, Recherches sur le M\u00e9-chanisme des Mouvements Respiratoires, in Archiv. G\u00e9n\u00e9r. de M\u00e9decine, 3me s\u00e9rie, tom. xv. 1842, and 4me s\u00e9rie, tom. i. ii. and iii. 1843. Bourgery, M\u00e9moire sur les Rapports de la Structure intime, avec la Capacit\u00e9 fonctionelle des Poumons dans les deux Sexes, et \u00e0 divers Ages, in Comptes Rendus, 23me Janvier,\n1843,\tand in Archives G\u00e9n\u00e9rales de M\u00e9decine, 4me s\u00e9rie, tom. i. 1843. Thomson, The Chemistry of Animal Bodies, Edinburgh, 1843. Valentin and Brunner, Ueber das Verh\u00e4ltniss der bei dem Athmen des Menschen ausgeschiedenen Kolens\u00e4uere zu dem durch jenen Process aufgenommenen Sauerstoff, in Archiv fur physiologische Heilkunde, von Roser und Wunderlich, Band ii. 1843 ; also Valentin\u2019s Lehrbuch der Physiologie des Menschen, Band i. Braunschweig, 1844. Scharling, Versuche \u00fcber die Quantit\u00e4t der, von einem Menschen in 24 Stunden ausgeathmeten, Kohlens\u00e4ure, in Annalen der Chemie und Pharmacie von W\u00f6hler und Liebig, Band xiv. 1843. Fortgesetzte Untersuchungen zur Bestimmung der Quantit\u00e4t von Kolens\u00e4ure, welche ein Mensch in 24 Stunden ausathmet, in Annalen der Chemie und Pharmacie, Band lvii. 1846. Andral and Gavarret, Recherches sur la Quantit\u00e9 d\u2019Acide Carbonique exhal\u00e9 par le Poumon dans l\u2019Esp\u00e8ce Humaine, in Annales de Chim. et de Phys. tom. viii.\n1843.\tMalcolm, Some Experiments on the Proportion of Carbonic Acid formed during Respiration in Typhus, in the London and Edinburgh Monthly Medical Journal, 1843. Dumas, Essai de Statique Chimique des Etres Organis\u00e9s, 3me edit. Paris, 1844. Enderlin, Physiologisch-Chemische Untersuchungen, in Annalen der Chemie und'Pharmacie, Band xlix. 1844. Boussingault, Analyses Compar\u00e9es de l\u2019Aliment consomm\u00e9 et des Excr\u00e9ments rendus par une Tourterelle, entreprises pour rechercher s\u2019il y a Exhalation d\u2019Azote pendant la Respiration des Granivores, Ann. de Chim. et de Phys. tom. xi.\n1844.\tScherer, Ueber die Farbe des Blutes, in Zeitschrift f\u00fcr rationelle Medizin, heraus-gegeben von Henle und Pfeufer, Band i. 1844. Bruch, Ueber die Farbe des Blutes, in Zeitschrift f\u00fcr rationelle Medizin, Band i. 1844. Noch einmal die Blutfarbe, in same journal, Band iii. 1845. Das Neuste zur Geschichte der Blutfarbe, in same journal, Band v. 1846. Hutchinson, Contributions to Vital Statistics, & c., in Journal of the Statistical Society of London, vol. vii. 1844. On the Capacity of the Lungs, and on the Respiratory Functions, &c., in London Medico-Chirurgical Transactions, vol. xxix. 1846. Marchand, Ueber die Respiration der Frosche, in Journal fur praktische Chemie, von Erdman und Marchand, Band xxxiii. 1844. Ueber die Einwirkung des Sauerstoffes auf das Blut und seine Be-standtheile, in same journal, band xxxv. 1845. Ueber die Anwesenheit der kolensauren Salze in dem Blute, in same journal, band xxxvii. 1846. Ueber die Farbe des Blutes, in same journal, Band xxxviii. 1846. Gay-Lussac, Observations Critiques sur la Th\u00e9orie des Ph\u00e9nom\u00e8nes Chimiques de la Respiration, in Annales de Chim. et de Phys. 3me s\u00e9rie, tom. xi. 1844. Hannover, De Quantitate relativa et absoluta Acidi Carboniei ab Homine sano et \u00e6groto exhalati, Hauni\u00e6, 1845. Mendelssohn, Der Mechanismus der Respiration und Cirkulation, Berlin, 1845. Vierordt, Physiologie des Athmens, Karlsruhe, 1845. Article \u201cRespiration,\u201d in Wagner\u2019s Handw\u00f6rterbuch der Physiologie. In Sachen der Respirationslehre. Noch eine Antwort an Herr P. L\u00f6wenberg in Berlin, in","page":367},{"file":"p0368.txt","language":"en","ocr_en":"368\nRODENTIA.\nZeitschrift fur rationelle Medizin, Hand v. 1846. Ludwig, Einige Bemerkungen zu Valentin\u2019s Lehren von Athmen und vom Blutkreislauf, in Zeitschrift fur rationelle Medizin, Band iii. 1845. Reuter, Beleuchtung der Versuche von Prof. Scherer und Dr. Bruch \u00fcber die Farbe des Blutes, in Zeitschrift fur rationelle Medizin, Band iii. 1845. Letellier, Influence des Temp\u00e9ratures extr\u00eames de l\u2019Atmosph\u00e8re sur la Production de l\u2019Acide Carbonique dans la Re-spiration des Animaux \u00e0 Sang chaud, in Comptes Rendus, torn. xx. 1845, and Annales de Chim. et de Phys. tom. xiii. 1845. Mulder, Zur Frage, auf welche Weise der Sauerstoff der Luft bei der Respiration vom Blute aufgenommen wird, in Holl\u00e4ndische Beitr\u00e4ge zu den anatomischen und physiologischen Wissenschaften, Band i. heft i. 1846. The Chemistry of Vegetable and Animal Physiology, translated from the Dutch by Dr. Fromberg, Edinburgh, 1845. Liebig, Ueber die Abwesenheit der kohlensauren Alkalien im Blute, in Annalen der Chemie und Pharmacie, Band lvii. 1846. Animal Chemistry, &c., edited by Dr. William Gregory, 3d edition, London, 1846. Moleschott, Versuche zur Bestimmung des Wassergehalts der vom Menschen ausgeathmeten Luft, in Holl\u00e4ndische Beitr\u00e4ge, &c., Band i. heft i. 1846. Snow, On the Pathological Effects of Atmospheres vitiated by Carbonic Acid Gas, and by a Diminution of the due Proportion of Oxygen, in Edinburgh Med. and Surg. Journal, vol. lxv. 1846. Fr. Nasse, Verbrennung und Athmen, chemische Th\u00e4tigkeit und organisches Leben, Bonn, 1846. Loewenberg, Bericht \u00fcber die neuesten experimentellen Leistungen in Bezug auf den chemischen Process des Athmens, in Beitr\u00e4ge zur experimentellen Pathologie und Physiologie, heraus-gegeben von Dr. L. Traube, Berlin, 1846. Harless, Monographie \u00fcber den Einfluss der Gase auf die Form der Blutk\u00f6rperchen von Rana temporaria, Erlangen, 1846. Sibson, On the Mechanism of Respiration, London Phil. Transact, for 1846. Lehmann, Ueber den Gehalt des Blutes an kolensauren Alkali, in Journal fur praktische Chemie, band xl. 1847.\n( John Reid.)\nRODENTIA(Glires, Linn.) (Fr. Rongeurs). \u2014 An important order of mammiferous Verte-brata, distinguishable by the remarkable structure of their incisor teeth, which are adapted to perform the office of chisels by cutting and gnawing away the hard vegetable substances, which form their principal food. The animals of this order, indeed, appear to be specially appointed to devour the hardest substances, generally living upon the wood and bark of trees, as well as upon nuts and other shelled fruits. The incisor teeth, which characterize the animals of this order, are situated in both jaws, and are separated from the molar by a considerable space, so that they are ill-adapted to seize living prey, or to devour flesh, notwithstanding that certain genera of rodents exhibit decidedly carnivorous propensities. These incisors, also called dentes scalprarii, are only provided with enamel upon their anterior surface, so that the posterior portion of the tooth being worn away more rapidly than the anterior, these teeth always present a chisel-like edge. The lower jaw is articulated to the cranium by a longitudinal condyle, in such a manner that it has no horizonal motion except from before, backward, and vice versa; a movement adapted to effect the act of\ngnawing. The molar teeth have their crowns flattened and traversed by plates of enamel, arranged transversely, the better to antagonise the backward and forward movement of the jaws.\nFig. 247.\nPteromys volitans.\nThose genera in which these layers of enamel are simple plates, and which have the crowns of their molar teeth very flat, are more particularly frugivorous ; those in which the eminences of these teeth are divided into blunt tubercles, are omnivorous ; whilst a small number of genera, which possess pointed molars, will attack other animals, and in some of their habits approximate the Carnivora.\nThis order comprises the following genera : \u2014\nSciurus (Squirrel). Pteromys (Flying Squirrel) (fig. 247,). Cheiromys (Aye-Aye). Arctomys (Marmot). Myoxus (Dormouse). Echimys. Uydromys. Capromys. Mus (Rat). Gerbillus. Meriones. Cricetus (Hamster). Arvicola (Vole). Fiber (Musk Rat). Geo-rychus (Lemming). Otomys. Dipus (Jerboa) (fig. 248.). Poephagomys. Helamys. Spalax (Rat Mole) (fig. 249.) Batlnergus (Cape Mole) (fig.2b0.). Geomys. Dipio-stoma. Castor (JBeaver). Myopotamus (Coui). Ilystrix (Porcupine). Lepus (Hare). Lago-mys (Rat Hare). Hydrochcerus (Capybara). Rhyzomys. Cavia (Guinea Pig). Dasyprocta (Agouti). Coelogenys (Paca). Chinchilla.","page":368},{"file":"p0369.txt","language":"en","ocr_en":"RODENTIA.\n369\nFig. 248.\nDipus hersipes.\nBones of the cranium. \u2014 The bones of the raina are united into ope, in front of which cranium in the Rodentia present several pecu- the sphenoid forms a single vertical lamella,\nFig. 249.\nFig. 251.\nSpalax typhtus.\nSkull of the Hare.\nliarities in their arrangement, which it will be an evident approximation to what is found in necessary to notice.\tbirds.\nFig. 250.\nBathiergus marithnus.\nIn the hare*, the anterior sphenoid is very The os frontis presents a strong supra-remarkable, inasmuch as the two optic fora- orbital crest, which is deeply notched both * Cuvier, Anatomie compar\u00e9e, last edition. before and behind. It advances on each side VOL. IV.\tB B","page":369},{"file":"p0370.txt","language":"en","ocr_en":"370\tRODENTIA.\nby a long process, between the ascending point of the inter-maxillary bone and that portion of the maxillary which forms the cheek : the parietals remain for some time distinct from each other, and from the inter-parietal ; which latter, in the rabbit, is small, and resembles an ellipse placed transversely : in the hare this last bone can only be detected in very young specimens, when it is found to consist of two small pieces, which are separated by a prominent angle of the occipital. The petrous portion of the temporal bone occupies a large triangular space in the occipital region of the skull. The mastoid process is entirely formed by the occipital bone ; but the os petrosum furnishes a parallel process, which embraces the temporal externally, and at an early period it becomes united therewith. The tympanic portion of the temporal is considerably arched, but is far from reaching the pterygoid processes. The temporal alae of the posterior sphenoid do not mount up very high, and do not reach the frontal, from which they are separated by the anterior sphenoid and by the temporal, still less do they approximate the parietal hones, which do not descend so low as the temporal.\nIn the marmot, the frontal and the parietal bones are at a very early age consolidated into a single piece, and an inter-parietal bone is not discoverable even in very young marmots. The frontal bones, which are extensively penetrated by the two ossa nasi, penetrate deeply between the parietals, which latter are narrow, and the sutures which connect them to the temporal remarkably straight and parallel. The occipital suture is situated a little in front of the occipital crest, with which it runs nearly parallel.\nOne-third of each side of this crest is formed by the petrous bone, which infringes slightly upon the occipital surface of the cranium. External to the tympanum, and a little behind it, there is a mastoid process ; behind which is another (the paramastoid), formed by the occipital bone. The tympanic bones are round and much inflated ; they are consolidated at an early age with the petrous bones. In the temple the posterior sphenoid mounts considerably upwards, but nevertheless only joins the temporal and the frontal, the parietal not descending sufficiently low. The orbital ala of the sphenoid enters but little into the composition of the orbit.\nIn the squirrel the separation between the parietals and the frontal bones is likewise obliterated at a very early period. The inter-parietal also becomes soon confounded w ith the parietal ; but in very young subjects its presence is well-marked ; it is of semi-circular form. There is, moreover, a special point of ossification in the centre of the cross, formed by the frontal and parietal bones. The glenoid cavity is more deeply excavated than in the marmot.\nIn the beaver, the frontals are consolidated together at a very early age ; the parietals also unite to each other and to the frontals, even before the inter-parietal has become blended with them. The inter-parietal is\ntriangular, and in very young subjects is double. The glenoid cavity is bioader than it is long; its external border only is formed by the jugal bone ; its posterior margin is altogether free. The tympanum is altogether formed by the tympanic bone. Between the two tympana the basilar region of the cranium is hollowed to such an extent as to be partly membranous, even in very old animals.\nThere are two mastoid tubercles placed near to each other ; one formed by the petrous bone, the other by the occipital. The petrous bone becomes united at an early period to the tympanic bone, a pointed apophysis of the temporal insinuating itself between them, behind the external auditory foramen.\nThe posterior sphenoid joins to the frontal in the temporal region ; the anterior sphenoid then mounts up very high ; and in adult specimens, when the molar teeth have come down, and the maxillary bones are no longer distended, there is inferiorly a compressed portion, by which the sphenoid joins the maxillary and the palatine bones, and which forms a partition pierced with several holes between the bottom of the two orbits.\nIn the Cape mole (Bathiergus) the sutures at the upper part of the cranium are disposed much in the same way as in the beaver, only in the larger species the temporals are broader anteriorly, and encroach upon the frontal in front of the parietal. The inter-parietal is of an oval shape. The temporal presents, posterior to its arch, a large fissure, which is not closed by the os petrosum ; the latter bone, however, on the other hand, fills up a deep notch, which exists on the external border of the occipital bone. The paramastoid apophysis is dilated into a prominent plate.\nFig. 252.\nSkull of the Bathiergus maritimus.\nThe anterior sphenoid, which enters but little into the composition of the orbit, forms beneath it a simple lamella, but which is not perforated. The posterior sphenoid does not ascend into the temporal, but a considerable prolongation of the frontal bone comes down to unite with it, about the level of the edge of the glenoid cavity ; it also furnished a process to be articulated both with the palatine and the maxillary bones.\nIn the ondatra and the water voles the parietal bones are, as it were, imbedded in the shape of a disk between the temporals. The temporal, moreover, furnishes a prominent projection, that might be mistaken for the","page":370},{"file":"p0371.txt","language":"en","ocr_en":"RODENTIA.\t371\npost-orbital apophysis of the frontal, which latter does not exist. The frontal bones,\nFig. 253.\nSkull of the Ondatra.\nwhich are consolidated together long before the parietal, are much reduced in size, in consequence of the extension of the temporals, and the narrowness of the inter-orbital space.\nThe inter-parietal remains for a long time distinct, it is very large, and is situated between the two parietals, the two temporals, and the sphenoid.\nThe posterior sphenoid mounts much higher into the temporal region than in the genus Bathiergus, and joins both the temporal and the frontal. The parietal does not reach within a considerable distance of it. The tympanum is prominent, and rests posteriorly upon a well-marked paramas-toid process. The suture between the tympanic and the petrous bone exists till a late period. The occipital portion of the petrous bone forms no tubercle, but penetrates deeply into the occipital.\nIn the rats, properly so called, the frontals which remain separate for a long period, are distinguished from the parietal by the intervention of a straight transverse line. Their inter-parietal is rectangular and placed transversely, but does not reach as far as the temporal bones. The posterior sphenoid does not mount into the temporal region to a greater height than the anterior; it there joins the frontal, but remains separated by a considerable space from the parietal.\nIn the gerbilles the fronto-parietal suture forms the arc of a circle. The inter-parietal is broad transversely ; its suture with the parietals is nearly straight, and it is embraced posteriorly and laterally by the occipital. The temporal, upon the sides of the cranium, is comparatively small in front ; it touches the frontal at the extremity of the frontop-arietal suture ; posteriorly it continues the suture, which, descending from the inter-parietal angle, separates the parietal from the occipital : the latter bone is deeply notched to receive the os petrosum, which it separates from the interparietal by a quadrilateral process. The arrangement of the bones in the orbit resembles that of the genus Mus. The tympana are extremely vesicular and prominent ; they bound posteriorly the glenoid cavity, which resembles a deep furrow. There are small paramastoid apophyses closely applied to them.\nIn the hamster (Cricetus) the inter-parieta is a small tri angular bone ; the temporal is extended at the expense of the parietal, and stretches as far back as the occipital. The orbital and temporal al\u00e6 of the sphenoid are arranged in the orbit as in the rats. There is no paramastoid process behind the condyles of the lower jaw.\nThe same observations are applicable to the dormice, but their inter-parietal bone is elongated transversely, so as to touch both the occipital, the parietal, and the temporal ; the posterior sphenoid, moreover, only touches the maxillary by its apex. A little process, derived from the palatine, separates them below. These animals have the zygomatic arch situated lower down and broader than the hamsters. Their tympana are much larger, well rounded, and in contact with the internal pterygoid processes.\nFig. 254.\nSkull of the Spalax typhlus.\nIn the rat moles (Spalax) the occipita bone is flanked by the ossa petrosa and the temporals, to form the occipital surface of the cranium ; but the occipital suture is as usual situated in front of the occipital crest\u2014 a circumstance which encroaches much upon the parietal bones. This disposition is in relation with the strength of the muscles that support the head. The parietal encroach upon the frontal by a pointed process. The temporal ridges unite together to form a single sagittal crest, and the zygomatic arches are very prominent, externally corresponding to the great size of the temporal muscles. There is no inter-parietal bone. The tympana are but slightly arched.\nIn the rhyzomys of Sumatra, on the contrary, it is the frontal which extends by a pointed process between the parietal ; and, moreover, the temporal bones mount upwards very high upon the cranium, so as to join the frontal; there is no inter-parietal bone visible. The os petrosum is visible upon the occipital aspect of the cranium. A process derived from the temporal, which contributes to form the occipital ridge, is interposed between the os petrosum and the external auditory tube. The tympanum is lofty and well-rounded, and separated from the petrous bone behind by a process of the occipital, which terminates in a paramastoid tubercle.\nIn the jerboas (Fipus, Gmel.), the lines of separation between the frontal and parietal\nb b 2","page":371},{"file":"p0372.txt","language":"en","ocr_en":"372\nRODENTIA.\nbones form a perfect cross; the inter-parietal bone is large and of a rhomboidal shape.\nIn the alactaga (Mus jaculus, Lin.), a species of the same genus, the inter-parietal is\nFig. 255.\nSkull of the Dipus hersipes.\nseparated from the temporal by a broad process divided from the occipital, which runs to join the parietal, as in the gerbilles (Ger-billus, Desmar, Meriones, Ilig). The os petro-sum occupies a considerable space in the occipital region ; but in the jerboa (Dipus) the great development of the ear renders important changes in the structure of this portion of the skull indispensable. All the hinder portion of the temporal bone is reduced to a thin osseous band, which is closely connected with the dilated tympanum and with the os petro-sum, surrounding entirely the auditory canal. Another narrow band is derived from the summit of the occipital bone, which runs to become united at a right angle with the above process derived from the temporal, so that a small triangular space is formed between the parietal, the occipital, and the temporal, in which is visible, at the upper part of the skull, that great vesicular mass, which occupies a part of its base and its posterior aspect. The paramastoid apophysis is a little tubercle which leans against the tympanum, and bounds posteriorly the articulating surface of the lower jaw.\nIn the helamys (Cape jerboa, or jumping hare), the structure of the skull in the vicinity of the ear is analogous to that of Dipus. The petrous bones arise to the upper part of the cranium, and there occupy a considerable space between the temporal and the inter-parietal bones, so that the temporals only give off a narrow band posteriorly, which does not reach the occipital bone, and does not surround the auditory passage, as in the jerboa. From the absence of any slip derived from the occipital bone, the upper portion of the os petrosum is not divided into two parts, as it is in the jerboa. The tympanum also is much less developed, and in its vicinity there is a very distinct paramastoid\nfjrocess. The inter-parietal, which is triangu-ar, moreover, touches the parietals, the ossa petrosa, and the occipital. The lines of separation between the frontals and the parietals form a cross ; the former are much larger than the latter. The anterior sphenoid is perforated at the bottom of the orbit. The temporal al\u00e6 do not ascend higher than the orbital, and remain widely separated from the parietal.\nIn the ecliimys (or porcupine rat of Az-zara), the line which separates the frontal\nfrom the parietal bones is straight. The interparietal is obliterated at an early age. A very distinctive character peculiar to the echimys is, that the occipital bone, as it descends laterally towards the ear, bifurcates in such a wray as to enclose the ascending portions of the tympanic bone and of the os petrosum, forming by itself both the mastoid tubercles instead of the posterior one only, as is usually the case.\nThe anterior sphenoid gives off an orbital plate, which is moderately elongated ; but the posterior is almost excluded, both from the temporal region and from the orbit, owing to the length of the temporal front of the suture in this part. It is hardly visible except at the base of the cranium. The articulating surface for the lower jaw is of a transverse form without any marginal boundary behind.\nIn the capromys the bifurcation of the occipital bone is equally distinct, but its two processes join inferiorly in such a way, that only a small hole is left occupied by the os petrosum. The orbital wing of the sphenoid is also less extensive.\nIn the porcupines the frontal bones are very wide in front between the lachrymals. In young animals, a large semi-oval inter-parietal is met with ; but this bone, as well as the parietals and the frontals, unite at a very early period into one piece ; they also at an early age become consolidated with the ossa nasi, so that these seven bones not only form one piece, but even become united to the temporals and to the occipital long before the bones of the face are anchylosed with each other. The os petrosum is scarcely discoverable at the back of the cranium, where it only forms a small tubercle embraced by two processes of the occipital, the interior of which represents the mastoid process of the temporal bone, and forms, external to the condyles of the lower jaw, a broad paramastoid apophysis. The posterior sphenoid does not reach so far as the orbit, or rise above the anterior, which latter is but slightly visible upon the exterior of the skull.\nIn the coendou the parietal bones are prolonged by a pointed process between the frontals ; the suture between them, and also between the inter-parietal and occipital, is obliterated. The tympanum is much arched ; the os petrosum hardly appears in the occipital region of the skull, but is slightly visible a little behind the tympanum above the paramastoid apophysis, which is of moderate size.\nIn the paca the frontal bones are much elongated ; the suture between them and the parietals is transverse ; the temporal extends backwards as far as the occipital ridge, and descends behind the tympanum over the base of the mastoid process, the point of which belongs to the occipital bone. The relations of the sphenoid orbital plates are as in the agouti, but the tympana are less prominent.\nIn the foetus, and in very young subjects, there are two parietal and two inter-parietal bones ; but these four pieces become at an early age consolidated into one.\nIn the Guinea-pig (Cavia) the parietal","page":372},{"file":"p0373.txt","language":"en","ocr_en":"RODENTIA.\t373\nbones and the inter-parietal, which is large, and of a semi-oval shape, are at an early period consolidated into one piece. The occipital bone extends beyond the occipital crest in the upper region of the skull, but the sides are formed by the temporal. The petrous bone, which is in early age consolidated with the tympanic, is slightly visible by a narrow slip in the occipital .region.\nThe tympana are much arched, but the pterygoid processes do not touch them, because the foramen lacerum anterius, which is very large, separates them. The superior maxillary bone is articulated posteriorly with the posterior sphenoid above the palatine, upon the occipital region of the cranium.\nIn the couia (Myopotamus, Commerson) the sutures between the frontal and parietal bones form a complete cross. The inter-parietal is united to the surrounding bones at an early age, but in young individuals it is very large, and divided into two pieces ; in the adult animal the zygomatic processes of the temporal bone formed at their extremities a strong hooked process, which winds down beneath the jugal bone. The posterior sphenoid does not enter into the composition of the orbit ; the os petrosum is visible externally in the occipital region of the skull, situated between the two mastoid processes, which are both formed by the occipital bone, but are of very unequal length ; the external is pointed, the inferior and internal is of much greater size, running backwards and outwards, compressed, pointed, and recurved.\nIn the agouti, the frontal and nasal bones remain separate, although the parietal and inter-parietal are united into one piece ; in young subjects the inter-parietal is of great size, and semicircular in its shape. The orbital plate of the sphenoid enters largely into the composition of the orbit, where it articulates by it posteriorly with the temporal. In the preceding genera it is to be remarked, that the posterior sphenoid is joined to the frontal, which is interposed between the temporal and the orbital al\u00e6 of the sphenoid; the tympana regularly arched. The os petrosum does not appear externally, but in addition there here re-appears a small portion of the ethmoid, interposed between the orbital ala of the sphenoid, the frontal and the lachrymal bones.\nIn the capybara the hinder portion of the cranium, as well as the occipital bone and the inferior region of the temple, resemble what is met with in the kerodon of Patagonia. The pararaastoid apophysis is excessively long, the tympana are small. The petrous bone does not appear at all in the occipital region of the cranium. The parietals and inter-parietals are consolidated into one piece at a very early age, and separate, by a process more acute than in any of the preceding genera, the cranial portion of the temporal bone into two branches; the frontals are likewise united together in very young animals.\nIn the viscache the squamous portion of the temporal bone is likewise deeply indented by a point derived from the parietal. The posterior\nbranch of this bifurcation, which is narrow at its commencement, enlarges as it approaches the occipital ridge. The inter-parietal and the parietals are united into one piece, the frontals are distinct, and the coronal suture is transverse. The zygomatic process of the temporal is directed almost horizontally, and this bone remains widely separate from the maxillary ; the posterior sphenoid unites with this latter bone, external to the palatine, which does not penetrate into the temple or into the orbit : the posterior sphenoid has no temporal ala, so that it reaches neither the frontal nor .the parietal bone\u2014a circumstance which has been already remarked in preceding genera.\nIn the Jcerodons, the frontal bones remain separate after the parietal and inter-parietal are conjoined. The fronto-parietal suture is transverse. The superior margin of the occipital is bent upon itself at a right angle, as in the hares, and articulates at the side of the cranium with the temporals, terminating laterally by a long, slender, vertical, paramastoid process. The temporal gives off posteriorly a lamina, or apophysis, which descends more or less in different species between the tympanum and the petrous bone. The latter bone is not visible externally in the occipital region, but is apparent upon the side of the head, above and behind the auditory passage. The connections of the bones in the orbit are not less remarkable than in the Guinea-pig. The temporal is in like manner developed at the expense of the posterior sphenoid ; but it is the former which becomes united by its apex to the extremity of the maxillary bone, the sphenoid which runs parallel with it only approaching the maxillary, from which it is separated by a slip derived from the os palati. The temporal, as in the preceding genera, is united in the orbit to the anterior wing of the sphenoid in the Guinea-pig, with this difference, however, that the temporal leaves it free externally. The petrous bone occupies a considerable surface in the occipital region of the skull, and likewise furnishes a mastoid tubercle at the base of the paramastoid apophysis, which resembles that of the couia; and which, at first, running outwards and backwards, suddenly bends inwards and forwards. The petrous bone occupies a large part of the occipital region, where it presents a flattened surface ; it also furnishes a mastoid tubercle at the base of the paramastoid apophysis, which resembles that of the couia, and which, at first, directed outwards and backwards, afterwards suddenly bends inwards and forwards.\nIn the chinchilla the connection of the frontal and of the parietal bones, as well as those of the sphenoid with the maxillary and with the temporal, are the same as in the viscache, but the great development of the ear causes differences in the posterior region. The paramastoid apophysis, which is strongly marked, is closely applied against the tympanum, and does not project inferiorly. The petrous bone, instead of presenting a flat sur-B B 3","page":373},{"file":"p0374.txt","language":"en","ocr_en":"RODENTIA.\n374\nface in the occipital region of the skull, is extremely dilated, insomuch, indeed, that this dilatation appears in the upper wall of the skull, in the shape of two large projections, bounded in front by the parietals, internally by a plate common to them and the occipital bone, and posteriorly by a long narrow transverse projection from the occipital, which is in contact with the petrous bone, and externally by another thin and pointed slip, which forms the posterior termination of the temporal bone, and which projects above the auditory meatus to join that derived from the occipital. We have seen, above, that in the jerboa a similar disposition exists.\nBones of the face.\u2014In the Rodentia the intermaxillary bones are of enormous dimensions, on account of the great size of the incisor teeth, so that the maxillary bones are pushed very far backwards ; these latter form a large portion of the inner wall of the orbit, into the composition of which the os palati enters but slightly, and sometimes, indeed, not at all. The anterior boundary of the orbit is formed by a process of the maxillary bone, which proceeds to contribute to the formation of the zygomatic arch in such a way that the os mal\u00e6 is, as it were, suspended in the centre of the arch between the apophysis, derived from the maxillary and the zygomatic process of the temporal bone.* It joins neither the frontal nor the sphenoid. The elongation of the ossa nasi is such that the opening of the nose is situated quite at the extremity of the snout.\nIn the aye-aye the bones of the nose are short and broad. The intermaxillaries mount up along their sides by a broad process, which occupies part of the snout, and are articulated to the frontal by a tolerably broad space ; they touch, likewise, the lachrymals which encroach upon the cheek ; while the canal situated between the latter bones, the maxillary, and the jugal, is out of the orbit. The jugal apophysis of the maxillary arises opposite the second molar tooth, and the boundary of the jugal bone is placed at the anterior base of the Z3'gomatic arch. It articulates with the lachrymal, both within and without. The orbit is very broad, and furnishes a large postorbital apophysis, which joins that derived from the frontal bone. The palatine bone advances but a little way into the palate, terminating by a straight suture between the last molar teeth. The palatine portion of the pterygoid al\u00e6 is simple ; their sphenoidal portion is divided into two laminae, the external of which is prolonged as far as the tympanum, to which it is articulated, as well as to the inner border of the glenoid surface. In the temporal region, the palatine bone remains behind the posterior margin of the maxillary, between the latter bone and the two sphenoids, only touching the frontal by its apex.\nIn the hares, the intermaxillary bone pre-\n* It will be seen from the details that follow, that the part played by the os mal\u00e6 in the construction of the cheek is not always so simple.\nsents, besides its palatine portion, which is large, a long ascending apophysis, which is at first imbedded between the maxillary and the os nasi, and subsequently between the latter and the apophysis of the frontal, to which latter it is connected. All that portion of the maxillary bone which forms the cheek is, in the adult animal, riddled with holes, so as to have the appearance of lace-work. The lachrymal in the orbit is tolerably large ; externally, it gives off a blunt hook, beneath which is the lachrymal canal, situated upon the very edge of the orbit. The zygomatic portion of the maxillary bone is short ; its inferior margin forms a ridge, which projects slightly externally, and presents a flattened surface, from which arises one of the portions of the masseter muscles. It is this surface which we shall see in other Rodentia become rounded into a more or less oblique vaulted space, and in others become transformed into a wide ring. The union between the maxillary and the jugal bones is so soon obliterated, that unless we examine very young individuals we should be tempted to believe that no jugal existed. This latter bone is arched in-feriorly, and extends by means of a process beneath the zygomatic portion of the temporal bone. Besides the floor with which it covers the roots of the teeth, the maxillary gives off a narrow plate, which mounts into the orbit as high as the os frontis, between the lachrymal, from which, however, it is separated by a membranous space and the anterior sphenoid. The vomer is visible at the hinder part of the septum, which separates the foramina inci-siva. The palatine occupies beneath the anterior sphenoid in the orbit a much greater space than in other Rodents ; inferiorly it extends as far as the third molar tooth, and is deeply indented as far as the fourth. The pterygoid al\u00e6 extend to the azygos portion, or to the body of the anterior sphenoid, but they are separated from that of the posterior sphenoid by a membranous space on each side. The posterior sphenoid has on each side two pterygoid plates, which are both of them contiguous to those of the palate bones ; the internal ones terminate in a slender point or style.\nIn the lagomys, the base of the zygomatic arch gives off a process, which is directed downwards; and the jugal bone, after having passed beyond the zygomatic process of the temporal, is prolonged directly backwards into a lengthened point.\nIn the marmot, the two nasal bones constitute the middle of the upper vault of the snout. On each side of them the ascending apophysis of the intermaxillary bones, which are broader than in the hares, run up to be articulated with the frontal, the anterior border of which is transverse and only slightly festooned. The external surface of the maxillary is concave beneath a ridge, which is continuous with that of the zygomatic arch, extending as far as the intermaxillary suture. Setting off from this point, the intermaxillary suture descends vertically to embrace the","page":374},{"file":"p0375.txt","language":"en","ocr_en":"RODENTIA.\t375\npalate, of which it occupies rather less than a third. The jugal bone reaches to the anterior base of the zygomatic arch, where it articulates with the lachrymal as well as with the maxillary bone ; it is connected with the zygomatic apophysis of the os temporis by a horizontal suture, which occupies all the second half of the arch, so that it extends as far back as the glenoid cavity, the external margin of which it fills. The lachrymal is of moderate extent in the orbit, but is scarcely visible beyond the margin of that cavity ; besides its canal, which is altogether within the orbit, there is a small unossified space between it and the maxillary bone, situated very near to the posterior opening of the sub-orbital canal. The large space occupied by the maxillary in the orbit keeps the lachrymal widely separated from the palatine bone, with which it articulates so extensively in the Carnivora. The palatine bone occupies, posteriorly, about one-fifth of the extent of the palate. After having formed the root of the pterygoid al\u00e6, it is prolonged between them for about half their length laterally ; it mounts up into the temporal region as high as just beneath the optic foramen ; it there spreads out backwards as far as the spheno-orbital foramen, and forwards, as the foramen which represents the spheno-palatine. The internal pterygoid process is not detached from the sphenoid, and terminates posteriorly in a long hook. The external pterygoid plate is very distinct ; although but little prominent, it covers the vidian foramen, and touches with its point the extremity of the maxillary.\nIn the squirrel, the lachrymal hook is formed by the bone of that name ; but it is also doubled by a similar unciform process, derived from the jugal. There is no membranous space between the lachrymal and the maxillary. The prolongations of the palatine bone between the pterygoid al\u00e6 are shorter. In other respects the relations of the bones to each other are very similar to what exists in the marmot.\nFig. 256.\nSkull of the Beaver ( Castor Fiber).\nIn the beaver, the post-orbital apophysis of the os mal\u00e6 is very large and blunt, and all this portion of the bone very broad ; it occupies the greater portion of the zygomatic arch. The two nasal bones are broader in their middle, and both the intermaxillary and max-\nillary bones reach up as far as the frontals. The lachrymals are small, especially that portion of them which is situated without the orbit, to which the jugal bones touch. The vaulted portion of the maxillary bone is very extensive and well circumscribed in adult animals ; on its external margin, by the ridge, which is continuous with the inferior edge of the zygomatic arch, and internally by another ridge, which commences close to the suborbital foramen, and mounts up on the cheek to join the ridge last mentioned. The palatine bone occupies in ,the palate a triangular space, extending as far forward as opposite the second molar tooth; it terminates posteriorly between the two pterygoid al\u00e6. The external pterygoid apophysis is of moderate length, nearly rectangular in its shape, and is pierced at its base by the vidian canal : it articulates broadly with the posterior part of the maxillary in such a way as to exclude the palatine both from the orbit and from the temple. The internal pterygoid apophysis is of a hooked form, the point of the hook reaching as far as thet)mpanum.\nIn the orycteres, the jugal bone commences at about the anterior fourth of the length of the zygomatic arch, and consequently remains widely separated from the lachrymal. The ossa nasi constitute scarcely half the breadth of the snout, in which the maxillary occupies much less space-, it being here the inter-maxillary which principally forms ;t. The last-mentioned bones mount up upon the forehead higher than the bones of the nose\u2014a circumstance which is the reverse of what occurs in the beaver. The concavity of the maxillary beneath the base of the zygomatic arch is reduced to a slight oval depression; but its zygomatic apophysis is very long ; it is the maxillary bone and the frontal, to which it is joined by a long suture, which forms almost alone the osseous walls of the orbit. There is no lachrymal suture visible, although the lachrymal canal is distinct enough. The external pterygoid apophysis presents neither crest nor prominent angle ; the internal resembles that of the beaver.\nIn the ondatra and the water voles, the bones of the nose, which are pointed at their summits, are considerably enlarged at their inferior extremities. The intermaxillaries occupy a smaller portion of the snout than the preceding pieces, the oblique excavation at the root of the zygomatic arch exists ; but it is separated from the cheek superiorly by the vertical prolongation of the sub-orbital foramen. The malar apophysis of the maxillary extends beneath the jugal until it almost reaches that of the temporal ; so that the jugal is onty free at its lower margin for a very small space, and is very far removed from the lachrymal, which latter bone does not appear external to the orbit, it being concealed in the sub-orbital canal. The os palati extends into the palate as far as the first molar tooth, but is not visible either in the orbit or in the temple, in which latter region the maxillary is connected to the two sphenoids and to the\nb \u00df 4","page":375},{"file":"p0376.txt","language":"en","ocr_en":"376\nRODENTIA.\nfrontal, as far as the lachrymal. The two pterygoid al\u00e6 are well developed and of equal size ; the internal are connected with the tympanic bones, as are the external ; and by their anterior margins the latter are connected with the maxillary to a greater extent than in the beaver, so that no part of the palatine is visible externally.\nIn the rats, properly so called, the bones of the nose likewise increase in breadth, towards their extremity, to an extent which varies in different species. The intermaxillaries are joined to the frontal by a suture consisting of extremely fine and numerous indentations : they form scarcely the half of the snout, comprehending the vault and the roof of the zygomatic arch, which is here directed much further outwards, and is separated from the rest of the cheek by a deep groove ; in front of this groove the maxillary is excavated into a sort of pouch, its zygomatic process is very long, the jugal bone short and slender. The lachrymal is entirely contained within the orbit, no part of it being visible at the point of union between the frontal and maxillary upon the margin of the orbit, but a prominent hook-process, situated within the edge of the orbital cavity. The palatine fills up half the space situated between the foramina incisiva and the hinder margin of the palate ; its pterygoid wings, moreover, are considerably prolonged between those of the sphenoid, but the external pterygoid al\u00e6 of the latter bone entirely cover it externally by passing to join the maxillary, as in the ondatra, nevertheless it shows itself in the floor of the orbit embraced in a fissure of the maxillary bone. The points of the internal pterygoid apophyses do not reach as far as the tympanum. There is between the pterygoid al\u00e6 a membranous space.\nIn the gerbilles, the bones of the nose and the intermaxillaries are prolonged in front, a little beyond the incisor teeth ; the suture between the intermaxillary is composed of radiated indentations; the maxillary bone expands into a very thin lamina at the anterior margin of the orbit; and this lamina is continuous with another given off' at this point by the lachrymal ; the jugal bone is very slender ; the palatine runs forward in the palate as far as the middle of the first molar tooth ; posteriorly it is not visible in the orbit, the articulation of the external wing of the sphenoid with the maxillary concealing it on the outer side, as in the preceding genera. The internal pterygoid apophysis reaches as far as the tympanum.\nIn the hamsters, the bones of the face closely resemble in their disposition those of the rats properly so called. In the dormice ( Myoxus), as in the gerbilles, the end of the snout projects beyond the incisor teeth ; and the intermaxillary bone occupies a large portion of the snout ; whence it results that it is prolonged upwards by a short ascending branch. In Myoxus nitela the maxillary presents beneath the sub-orbital hole a prominent tubercle, which does not exist in the dormouse (Myoxus Glis). Both of them have a mem-\nbranous space in each of their palatine bones ; and, moreover, this bone retakes its usual position between the maxillary and the sphenoid upon the outer side of the pterygoid ala, so that the latter is only in contact with the maxillary by its apex, nearly in the same manner as in orycterus.\nIn spalax (the rat mole), the bones of the nose become at an early period consolidated together for a portion of' their length, they expand inferiorly, and are proportionally of larger size than in orycteres. The process of the maxillary which surrounds the infra-orbital hole is broad and thin ; the jugal is very slender, and does not at all contribute to form the inferior rim of the orbit ; the external pterygoid apophysis almost cover's the foramen ovale.\nIn the rhizomys of Sumatra, the fronto-maxillary suture continues the line of union between the frontal bone and the other bones of the face. The bones of the nose are separate, and the frontals consolidated together : the bones of the nose are here of a triangular form. The lachrymal is entirely contained in the orbit ; the jugal, which is broad, occupies \u00b1 the centre of the zygomatic arch ; the palatine is small, and of a triangular shape in the region of the palate; it is not visible in the orbit, on account of the union between the ala of the sphenoid and the maxillary bone, which is as extensive as in the ondatra. The internal pterygoid apophysis is prolonged into a long hook.\nIn the jerboa, properly so called, and in the alactaga, the jugal ascends at a right angle along the posterior edge of the great pre-orbital ring as far as the lachrymal, with which it is connected. In the jerboa this part is enlarged into a broad lamina ; in the alactaga it is a simple, stem-like process. The maxillary takes beneath the sub-orbital hole the form of a large ring, which might almost be mistaken for an orbit. The lachrymal forms towards the upper part of this ring a broad hood-like process. The bones of the nose cover the whole upper part of the snout, and are even bent a little into a tubular form at their extremity. The ascending ramus of the intermaxillary is very narrow at its origin, between the nasal and the maxillary ; it afterwards spreads out as it approaches the frontal, with which it is connected on a level with the bones of the nose by a finely serrated suture.\nIn thepcephagomys the jugal is broad, it gives off a post-orbital apophysis, and does not mount along the pre-orbital ring. The face of this animal offers a very remarkable peculiarity. A cylindrical tube, bent into an arched shape, traverses the great ring, and is applied beneath the orbit against the alveolar arch. In this genus, as in the preceding, the maxillary is connected with the sphenoid.\nIn the helamys the jugal is broader, and extends along a little more than half of the ring ; the rest is completed by the lachrymal, and even by the frontal bone. The lachrymal in this genus has no hook-like process : after-having shown itself external to the orbital\n4","page":376},{"file":"p0377.txt","language":"en","ocr_en":"RODENTIA.\nring, it occupies a considerable space in the orbital cavity ; but the entrance of the lachrymal canal is concealed by the sub-orbital arch. The bones of the nose are singularly robust ; the ascending ramus of the intermaxillary is, on the contrary, very narrow, even at the point where it joins the frontal. The preorbital ring is of large size, and the malar apophysis of the maxillary arises close to the intermaxillary suture. A few lines behind the incisor teeth the palatine interposes itself, under the shape of a round shield-like plate, between the sphenoid and the maxillary.\nIn the echimys the jugal is very long, and tolerably broad ; the lachrymal is small, and is furnished with a little hook-like process ; the maxillary presents, inferiorly, in front of the molar teeth, a small fossa and a malar apophysis, the margin of which is broad and flattened. The bony arch of the pre-orbital ring is simple, and not doubled posteriorly by an ascending apophysis ofthejugal, as is the case in the jerboa ; or by the latter and the lachrymal, as in the helamys and the viscache. The palatine is deeply indented posteriorly, but it ascends into the orbit, and likewise appears in the pterygoid ala, between the sphenoid and the maxillary. The external pterygoid al\u00e6 do not extend transversely beneath the foramen ovale.\nThe capromys very nearly resembles the preceding genus in the construction of its face, but in it the jugal bone is broader, and almost rhomboidal in its shape. The sphenoid also is in contact with the maxillary, above the point of union between this bone and the pterygoid portion of the palatine.\nFig. 257.\nSkull of the Porcupine ( Hystrix cristata).\nIn the common porcupine (Hystrix cristata, Lin.), the bones of the nose are very large and broad, the suture connecting them with the frontal mounts much higher up than the intermaxillary sutures. The intermaxillary bones have their ascending ramus much less narrow than in the preceding genera. The maxillary is hence a pre-orbital ring, which is much broader than it is high ; and the inferior horizontal portion of its circumference is much more slender than the vertical posterior portion. The lachrymals consist of a small portion situated external to the orbit, which furnishes a little hook-like process, and of another portion situated within the orbit, which is also of small\n377\nsize. The jugal is of moderate dimensions\u00bb and broader in front than it is posteriorly ; the palatine is deeply indented, and only sends off a little tongue-like pointed process to penetrate the orbit ; but it completely separates the sphenoid from the maxillary. The internal pterygoid processes end in hook-like terminations, the extremities of which are united to the tympanum ; the external ones only represent a transverse bar, into the composition of which the palatine slightly enters.\nIn the cuendu (Hystrix prekensilis, Lin.), the bones of the nose are short and flattened at their anterior portion ; they are likewise remarkably broad and mount very high up. The pre-orbital ring is higher than it is broad. The internal pterygoid process extends as far as the tympanum. In the arsons (Hystrix dorsata, Lin.), the pre-orbital ring is larger than in either of the preceding genera, and\" its two arches are of equal strength ; the bones of the nose are short, flat, and one third narrower than those of the cuendu. In both genera, the lachrymal is united, at an early age, both with the maxillary and the frontal. The intermaxillary suture is straight and almost vertical. In the coni (Myopotamus, Commer-son; Mus coipus, Molin.), the bones of the nose are broad and much elongated ; they do not mount higher than the intermaxillaries. The suture between the latter bones forms a very rounded arch, which is concaved posteriorly. The maxillary has the inferior edge of its malar apophysis very much flattened. The pre-orbital ring is large. The palatine is in contact with the maxillary below, but above the sphenoid joins that bone likewise, as in Orvcterus and other genera.\nIn the agouti {Chloromys, Fred. Cuv. ; Dasyprocta, Ilig.), the lachrymal, which is larger than in the allied genera, contributes to surround the sub-orbital foramen superiorly, so that the ring formed around this hole by the maxillary is not complete. The lachrymal comes down very nearly as far as the jugal bone, but does not touch it. The jugal itself is verv small. The pre-orbital ring is broader than it is high ; and there is, moreover, internal to it, situated upon the cheek just above the commencement of the malar apophysis, a long oval sinus, into which, both before and behind, a rounded canal opens. Inferior^, the palate bone advances in a wedge-like manner as far as opposite to the first molar tooth ; it penetrates into the orbit by a thin slip, which separates the sphenoid from the maxillary. The internal pterygoid al\u00e6 are prolonged as far as the tympanum by a broad hook-like process ; the'external form simple plates, to the construction of which the palatines partially contribute. There is a membranous space on each side, at the base of the union between the palatines and the internal pterygoid. In the pacas (C\u0153logenys, Fred. Cuv. ; Cavia Paca, Lin.), the maxillary portion of the zygomatic arch conceals beneath it an enormous sinus, which is less deep in very young subjects than in adult animals. This swelling, which fills up a portion of the","page":377},{"file":"p0378.txt","language":"en","ocr_en":"378\nRODENTIA.\npre-orbital ring, causes the latter to be rauch elongated transversely. And towards its in-\nFig. 258.\nSkull of the Ccelogynus.\nner angle there is an excavation resembling a long furrow or serai canal, which is really the infra-orbital canal. The jugal is much hio-her than it is broad ; the palatine extends into the palate as far forward as the first molar tooth : in the orbit it is almost hidden by the projection of the maxillary ; nevertheless, it is interposed between that bone and the sphenoid, and at the posterior extremity of the alveolar arch.\nIn the Guinea-pigs (An\u0153ma, Fred.\nCuv. ; Cavia, Ilig. ; Musporcettus, Lin.), the lachrymal is large ; but it does not entirely form the upper [root of the pre-orbital ring, and the maxillary is not interrupted at this point. The preorbital ring is much wider than it is high.\nWe may remark in this genus both the groove of the paca and the fossa of the agouti; but the latter is situated higher up, as in the rats. The ascending branch of the maxillary is long and narrow. The bones of the nose are broader in front than behind-. The jugal only commences towards the middle of the zygomatic arch ; the palatine, which superiorly does not penetrate either into the orbit or into the temporal region, extends in the palate only as far forward as the interval between the second and the third molar teeth.\nIn the kerodons, a small point of the frontal insinuates itself above, between the bones of the nose and the intermaxillaries, the ascending branch of the latter being very long, and extremely narrow at its origin, in the Brazilian species. In this species, likewise, the pre-orbital ring is oval, and much elongated transversely, but formed entirely in the maxillary bone as it is in the Guinea-pig ; whilst in the kerodon of Patagonia the lachrymal forms by itself nearly the whole vertical portion of its arch, so that the lachrymal is necessarily of very great size. Posteriorly, the maxillary touches by its apex a long point derived from the temporal external to the palatine ; the latter, however, is enclosed between the sphenoid and the maxillary, and mounts up into the floor of the orbit, when it is connected with the lachrymal bone. In the palate it is very deeply notched.\nIn the eapyhara (Hydroch\u00e6rus, Erxleben), the jugal is still shorter than in the Guinea-\npig. The lachrymal is largely developed at the root of the vertical arch of the pre-orbital ring, but does not assist in forming it. The bones of the nose are very large and rectangular. The ascending ramus of the intermaxillary, on the contrary, is extremely narrow, and is only united by its point to a point derived from the frontal. The inferior horizontal arch of the ring is broad and flattened, with a little fossa at its base, as in the kerodons ; the maxillary is connected behind with the temporal, near the glenoid facet, external to the palate bone ; but what distinguishes capybara from them is, that this articulation is much more extensive, and that we cannot see, within, the long pterygoid apophysis and that portion of the palatine alluded to above. The external pterygoid al\u00e6 are obliterated ; the internal al\u00e6 terminate by a rounded plate, which is very far from reaching as far as the\nFig. 259.\nSkull of the Capybara.\ntympanum. The palatine encroaches upon the palate as far forward as the third molar Fig. 260.\n6\nSkull of the Chinchilla.\na, b, c, portions of the temporal bone, which is here very remarkable on account of the extraordinary development of the tympanic cavity ; e, meatus auditorius externus ; f the occipital bone ; g, the parietal ; h, h, the frontal ; i, zygomatic portion of the temporal, which in this animal is quite detached from the preceding portions ; k, malar hone ; l, ossa nasi.","page":378},{"file":"p0379.txt","language":"en","ocr_en":"tooth, and is interposed behind, between the maxillary and the sphenoid.\nIn the viscache and the chinchilla, the bones of the nose are oval and elongated ; the ascending branches of the intermaxillaries very narrow at their origin ; but they enlarge as they approach the frontal, as in the jerboas. The maxillary, in both, forms the entire preorbital ring ; but in the viscache the vertical portion of the arch is doubled posteriorly, as in the helamys, by an ascending branch of the jugal, by the lachrymal, and by the frontal bones. At the bottom of the ring there is a deep groove, almost entirely separated from it by a vertical plate, as in the alactaga. In the chinchilla, the jugal does not reach as far as the lachrymal, and in the pre-orbital ring there is only a very superficial furrow, with no vertical plate of separation. In both species the\nFig. 261.\nBase of the skull of the Chinchilla, b, b, tympanic portion of temporal bone ; f, occf pital bone; m, mastoid bone; n, palate bone o, the sphenoid ; p, the superior maxillary bone.\n\u00cfTIA.\t379\npalatine is very deeply notched, it articulates with the maxillary, except externally, where a point of the posterior sphenoid touches the latter bone : moreover, on account of the entire absence of the external wall of the pterygoid fossa, the palatine is found to occupy a considerable space in the floor of the orbit, between the orbital alas and the maxillary : it does not, however, mount upwards, as in the kerodon, between the latter bone and the frontal, to become connected with the lachrymal. The internal pterygoid apophysis is largely connected with the tympanum.\nBones of the carpus.\u2014 Generally, in the Rodentia, the os magnum is divided into two, as it is in the monkeys ; in the porcupine this is not the case, but there is a supernumerary bone interposed between the os pisiforme and the metacarpal bone of the fifth finger connected with the os unciforme.\nThe hare and some other Rodents have one carpal bone more than the human subject ; it is situated between the scaphoid, the trapezium, and the os magnum, of which last it appears to be a dismemberment; but the beaver, the marmot, the squirrel, the rats, and the agoutis have, like the Carnivora, a single bone representing the scaphoid.\nThe supernumerary bone is as large as the ordinary pisiform, and often much larger. Sometimes, as in the jerboa and the marmot, there are two supernumerary bones, so that, on each side of the wrist, there is a bone of equal size out of rank.\nIn the capybara the scaphoid and the semilunar bone are united without any supernumerary ossicle ; a small one, however, exists in the Guinea-pig. The paca, the agouti, and the capybara have the os magnum divided ; these three animals possess, as the rudiment of the thumb, a small bone situated upon the trapezoid, with which it is articulated.\nIn the marmot and the agouti this rudiment is composed of three ossicles ; and there is, moreover, an internal supernumerary bone.\nSkeleton of the Hare (Lepus timidus').","page":379},{"file":"p0380.txt","language":"en","ocr_en":"380\nRODENTIA.\nIn the order Rodentia the structure of the thumb differs in different genera ; there is a complete but short thumb in hares, beavers, and jerboas ; an incomplete thumb, consisting of only two phalanges, in squirrels, rats, porcupines, pacas, and agoutis ; and a thumb, represented by only a single ossicle, in the capybara, the Guinea-pig, the marmot, &e.\nIn connection with the fore-arm it may be observed, that the rabbit has only one pronator of the wrist, corresponding to the pronator teres ; a circumstance easily accounted for by the very small degree of motion permitted between the bones of the fore-arm ; in most other Rodentia, however, both the pronators are present.\nSkeleton of the Beaver ( Castor Fiber).\nThe terminal phalanges of the fingers are generally very slender, elongated, almost straight, and pointed, except in the capybara, which has its last phalanges of a triangular shape, and enclosed in strong horny hoofs.\nIn those Rodentia which have a complete clavicle, the muscles of the shoulder resemble very nearly in their disposition those of the human subject. The humerus resembles that of the Carnivora in its mode of articulation with the fore-arm ; but in those genera that are without clavicles, the articulation of the elbow joint resembles more nearly what is met with in herbivorous quadrupeds, being a simple hinge joint. The humerus of the beaver is much expanded at its ulnar extremity, and the deltoid crest is pro-\nIn the Rodentia the general form and position of the pelvis is nearly similar to what exists in the Carnivora.\nThe femur is in the beaver very broad, flattened from before to behind, and exhibits along its outer surface a sharp crest, which represents the linea aspera, and which is prolonged towards its middle into an apophysis, which has been named the third trochanter. This third trochanter is also met with in other rodents, as, for example, in the musk rat ; in the hares it is placed so high up, that it appears to be a derivation from the great trochan-\nFig. 263.\nFig. 264.\nSkeleton of the Flying Squirrel (Fteromys volitans).\nlonged inferiorly into a prominent point ; a circumstance which is likewise observable in the rat, the water vole, the ondatra, and in many other genera.\nIn the hares, the porcupine, the paca, and the agouti, the humerus near the elbow joint is completely perforated.\nter ; in other genera, as in the water vole, the rats, the squirrels, and the marmots, it is a simple crest, or external linea aspera ; in all the Rodentia the great trochanter is very prominent, and the neck of","page":380},{"file":"p0381.txt","language":"en","ocr_en":"RODENTIA.\t381\nthe thigh bone considerably narrower than its its posterior aspect there is likewise a promi-head-\tnent crest. It results from this structure,\nFig. 265.\nSkeleton of the Paca ( C\u0153logenys Paca).\nThe Rodentia have the fibula situated quite behind the tibia ; in rats, voles, jerboas, the beaver, the helamys, and the rabbit, it becomes consolidated with the tibia towards the lower third of its length, a wide triangular space being left between the two bones at the upper part of the leg ; the anterior crista of the tibia in all the above genera is remarkably prominent, as is the internal edge ; and upon\nthat, viewed from behind, the tibia exhibits, in the upper half of its length, two deep foss\u00e6 for the attachment of the tibialis posticus and the flexor longus pollicis. This structure is more particularly remarkable in the ondatra.\nIn the beaver the fibula gives off from its upper extremity a strong recurrent apophysis, which is directed slightly outwards. In some genera the fibula is excessively slender, and does not reach so low down as to become connected with the lower extremity of the tibia.\nIn those Rodents which have the fibula consolidated with the tibia towards its tarsal extremity, the tarsus seems to be articulated with the latter bone only ; but if very young\nFis. 266.\nSkeleton of the Jerboa (Dipus hersipes'). {Altered from Pander and D'Alton.)\nindividuals are examined carefully, it is pei ceptible that the external malleolus is torme by the fibula.\nIn Rodentia the os calcis is very muc elorg ted posteriorly.\nIn such genera as have five complete toes th following circumstances may be remarked : -In the beaver the os scaphoides is divide\u00ab into two portions, one placed in front of th< astragalus, which supports the second an< third cuneiform bones, and one placed inter nal to the astragalus, to which is attached thi cuneiform bone that supports the great toe","page":381},{"file":"p0382.txt","language":"en","ocr_en":"382\tRODENTIA.\nand a supernumerary flattened bone situated along the inner margin of the tarsus. The same disposition of these bones exists in the genera spalaxand eapromys, in the marmot, squirrels, and porcupines ; but in the four latter genera the supernumerary bone is of smaller size.\nThe rats and the paca have their os scapho\u00efdes divided, but are without any supernumerary bone. Among \u00e0those genera which have only four toes, such as the helamys, or Cape jerboa, which has its foot exceedingly elongated, the inferior tubercle of the scaphoid, which is observable in the sole of the foot of all rodents, is very long and prominent. Upon the internal margin of the tarsus there are in this animal some elongated flat bones, which are the rudiments of the great toe.\nIn the jerboas, properly so called, both the internal and external metatarsal bones are extremely small, and the three others are consolidated into one bone, upon the distal extremity of which are three articulating surfaces which support the phalanges of the toes.\nIn the rabbit and the hare, animals which resemble the jerboa in the great size of the tubercle of the scaphoid, the rudiments of the great toe become consolidated at an early age with the metatarsal bone of the second toe.\nIn the capybara, the Guinea-pig, the mara, and agouti, which have only three toes, the internal portion of the scaphoid supports a single bone, representing the cuneiform and a rudiment of the inner toe ; the cuboid likewise supports a small bone, which is a rudiment of the outer toe. The disposition of the toes varies considerably in the different genera of Rodents ; in the beaver, the inner toe is nearly of equal length with the others ; in the marmot, the porcupine, and the rats, it is considerably shorter ; in the paca it is nearly obliterated ; and in the Cape jerboa it is a mere rudiment, consisting of but a single bone ; in the hares not even this rudiment is perceptible.\nIn the capybara, the agouti, and the Guinea-pig both the inner and outer toes are reduced to a single bone.\nThe jerboa {Mus jaculus') and the alactaga {Mus sagitta) have their three middle metatarsal bones consolidated into one piece. The two lateral toes are distinct in the jerboa, but of comparatively small size ; in the alactaga they are quite wanting.\nTeeth. \u2014 The distinguishing character of the order of quadrupeds under consideration is the remarkable arrangement of their dental system, by which they are enabled to erode the hardest vegetable substances. The chief food of many genera, indeed, consists of the bark, wood, and even the hard fruits of trees, to devour which necessarily requires great strength of jaw, and such a disposition of their incisor teeth as to convert them into strong chisel-like cutting weapons, the edges of which never become blunted even to the latest period of life.\nThese incisor teeth, called also dentes scalprarii, are situated in the front of the\nmouth,' and are generally two in number in each jaw, except in the genus Lepus, embracing the hares and rabbits, which possess two small additional incisors, situated behind each of the large ones contained in the upper jaw.\nBetween the incisors and the molar teeth there is a considerable vacant space, by which arrangement the play of the anterior chisels is much facilitated, their action being likewise materially assisted by the mode of articulation of the lower jaw, which allows of considerable movement from behind forwards, and by the great power of the pterygoid and masseter muscles. The molar teeth are likewise exceedingly strong, and vary considerably in their mode of implantation in the jaws of different genera.\nThe incisors* are always regularly curved, the upper ones describing a larger segment of a smaller circle, the lower ones a smaller segment of a larger circle; these are the longest incisors, and usually have their alveoli extended below or on the inner side of those of the molars to the back part of the lower jaw. Like the molars of the Megatherium, and other teeth of unlimited growth, the implanted part of the long and large incisors retains the form and size of the exposed part or crown to the widely open base, which contains a long, conical, persistent dentinal pulp, and is surrounded by the capsule in a progressive state of ossification as it approaches the crown, an enamel pulp being attached to the inner side of that part of the capsule which covers the cqnvex surface of the curved incisor. The matrix is here noticed in connection with the tooth, because it is always found in full development and activity to the time of the Rodent\u2019s death. The calcification of the dentinal pulp, the deposition of the earthy salts in the cells of the enamel pulp, and the ossification of the capsule proceed contemporaneously ; fresh materials being added to the base of the vascular matrix as its several constituents are progressively converted into the dental tissues in the more advanced part of the socket. The tooth thence projecting consists of a body of compact dentine, sometimes with a few short medullary canals continued into it from the persistent pulp cavity, with a plate of enamel laid upon its anterior surface, and a general investment of cement, which is very thin upon the enamel, but less thin in some Rodents, upon the posterior and lateral parts of the incisor. The substance of the incisor diminishes in hardness from the front to the back part of the tooth ; the enamel consisting of two layers, of which the anterior and external is denser than the posterior layer, and the posterior half of the dentine being by a modified number and arrangement of the calcigerous tubes less dense than the anterior half.\nThe abrasion resulting from the reciprocal action of the upper and lower incisors pro-\n*\nOwen, Odontography, p. 398.","page":382},{"file":"p0383.txt","language":"en","ocr_en":"RODENTIA.\nduces accordingly an oblique surface, sloping from a sharp anterior margin formed by the dense enamel, like that which slopes from the sharp edge formed by the plate of hard steel laid upon the back of a chisel; whence the name dentes scalprarii given to the incisors of the Rodentia.\nThe varieties to which these incisors are subject in the different Rodents are limited to their proportional size, and to the colour and sculpturing of the anterior surface. Thus in the Guinea-pig, jerboa, and squirrel the breadth of the incisors is not half so great as that of the molars, whilst in the coypa they are as broad, and in the Cape mole rats (Bathyergus and Orycteromys) broader than the molars.\nIn the coypa, beaver, agouti, and some other Rodents, the enamelled surface of the incisors is of a bright orange or reddish brown colour. In some genera of Rodents, as orycteromys, otomys, meriones, gerbilla, hydrochaerus, lepus, and lagomys, the anterior surface of the upper incisors is indented by a deep longitudinal groove. This character seems not to influence the food or habits of the species ; it is often present in one genus and absent in another of the same natural family; in mostRodents the anterior enamelled surface of the scalpriform teeth is smooth and uniform.\nThe molar teeth are always few in number, obliquely implanted and obliquely abraded, the lateral series converging anteriorly in both jaws ; but they present a striking contrast to the incisors in the range of their varieties, which are so numerous that they typify almost all the modifications of form and structure which are met with in the molar teeth of the omnivorous and herbivorous genera of other orders of Mammalia.\nIn some Rodents the molar teeth are rootless, like those of the wombat, the toxodon, and elasmothere; some have short roots tardily developed, like the molars of the horse and elephant ; and some soon acquire roots of the ordinary proportional length.\nThe Rodents which have rootless molars comprise the families of the hares, chinchillas, Chili rats, and cavies; most of the\nFig.\n383\nvoles, the houtias (Capromys), and the Cape jerboa (Helamys).\nThe genera which Have molars, with short or incomplete roots, developed late, are Castor (beaver), Hystrix (porcupine), C\u0153logenys (spotted cavy), JDasyprocta (agouti), Spalax (blind rat), Myopotamus (coypa), Euryotis, Accomys, and Aplodontia.\nThe families of the squirrels, dormice, rats, and jerboas have rooted molars.\nThe differences in the mode of implantation of the molar teeth relate to differences of diet. The Rodents, which subsist on mixed food, and which betray a tendency to carnivorous habits, as the true rats, or which subsist on the softer and more nutritious vegetable substance, as the oily kernels of nuts, suffer less rapid abrasion of the molar teeth ; a minor depth of the crown is therefore needed to perform the office of mastication during the brief period of existence allotted to these active little mammals ; and as the economy of nature is manifested in the smallest particulars as well as in her grandest operations, no more dental substance is developed after the crown is formed than is requisite for the firm implantation of the tooth in the jaw.\nRodents that exclusively subsist on vegetable substance, especially the coarser and less nutritious kinds, as herbage, foliage, the bark and wood of trees, wear away more rapidly the grinding surface of the molar teeth ; the crowns are therefore larger, and their growth continues by'a reproduction of the formative matrix at their base, in proportion as its calcified constituents, forming the exposed working part of the tooth, are worn away. So long as this reproductive force is active the molar tooth is implanted, like the incisor, by a long undivided continuation of the crown ; when the force begins to be exhausted the matrix is simplified by the suppression of the enamel organ, and the dentinal pulp continues to be reproduced only at certain points of the base of the crown, which by their elongation constitute the fangs. The beaver and other Rodents in the second category of the order, according to the implantation of the molar teeth, exemplify the above condition ; but in the capybara, dolichotis,\nLower jaw of the Porcupine (Hystrix cristata).\ni, incisor tooth; m, the molar teeth, implanted in the jaws by means of fangs; i*, pulp at the base of\nincisor tooth ; p, anterior molar.","page":383},{"file":"p0384.txt","language":"en","ocr_en":"384\nRODENTIA.\nand other Rodents with rootless molars, the already been cited ; but in the rootless molars, reproduction of the molar, like that of the in- where the folds of enamel extend inwards from cisor teeth, appears to continue throughout the entire length of the sides of the tooth, the the animal\u2019s existence. The rootless and per- characteristic configuration of the grinding petually growing molars are always more or surface is maintained without variation, as in\nFig. 208.\nUpper jaw of the Patagonian Cavy ( Chlor omys Patagonica).\n*, incisor tooth, laid bare throughout its whole length; m,p, molar teeth implanted without fangs into\narched sockets.\nless curved ; they derive from this form the same advantage as the incisors, in the relief of the delicate tissues of the active vascular matrix from the effects of the pressure which would otherwise have been transmitted more directly from the grinding surface.\nThe complexity of the structure of the crown of the molar teeth, and the quantity of enamel and cement interblended with the dentine, are greatest in the rootless molars of the strictly herbivorous Rodents. The crowns of the rooted molars of the omnivorous rats and mice are almost as simple as the tuber-culate molars of the bear, or of the human subject, which they appear to typify. They are at first tuberculate ; when the summits of the tubercles are worn off, the inequality of the grinding surface is for a time maintained by the deeper transverse folds of enamel, the margins of which are separated by alternate valleys of dentine and cement ; but these folds, sinking only to a slight depth, are in time obliterated, and the grinding surface is reduced to a smooth field of dentine, with a simple border of enamel. A similar change in the grinding surface, consequent on age and use, is shown in the molars of the souslik, or ground squirrel; as also in those of the gerbille, and is common to all that possess roots. It will be seen that these folds have a general tendency to a transverse direction across the crown of the tooth. Baron Cuvier has pointed out the concomitant modification of the shape of the joint of the lower jaw, which almost restricts it to horizontal movements to and fro, in the direction of the axis of the head, during the act of mastication. When the folds of enamel dip in vertically from the summit to a greater or less depth into the substance of the crown of the tooth, as in those molars which have roots, the configuration of the grinding surface varies with the degree of abrasion, of which examples have\nthe Guinea-pig, the capybara, and the Patagonian cavy.\nThe whole exterior of the molar teeth of the Rodentia is covered by a cement, and the external interspaces of the enamel folds are filled with the same substance. In the chin-chilid\u00e6 and the capybara, where the folds of enamel extend quite across the body of the tooth, and insulate as many plates of dentine, these detached portions are held together by the cement ; such folds of enamel are usually parallel, as in the large posterior lower molar of the capybara, which, in shape and structure, offers a very close and interesting resemblance to the molars of the Asiatic elephant.\nThe partial folds and islands of enamel in the molars of the porcupine and agouti, typify the structure of the teeth of the rhinoceros ; the opposite lateral inflections of enamel in-the molars of the gerbille and Cape mole-rat represent the structure of the molars of the hippopotamus ; the double crescentic folds in the jerboa sketch out, as it were, the characteristic structure of the molars of the Anoplothere and Ruminantia.\nAlthough, as has been shown, the molar teeth in many Rodents are rootless and of unlimited growth, as in the Edentata, in none is enamel absent ; or vascular dentine, as the chief constituent of the tooth, present. These essential differences characterise the molars of those Rodents, which by use have their grinding surface reduced to a simple depression bounded by a raised circular margin, as in the great Cape mole; that margin being formed by true enamel, but in the sloths by hard dentine.\nIt is peculiar to some of the Rodents with rootless molars to have the sockets of these long curved teeth open at both extremities, so that, in the dry skull, the base of the tooth protrudes as well as the grinding surface ; the matrix in such instances adheres to the peri-","page":384},{"file":"p0385.txt","language":"en","ocr_en":"RODENTIA.\n385\nosteum, which covered the portion of bone absorbed from the bottom of the alveolus. The jumping hare (Helamys capensis), when full grown, offers a good example of this curious structure.\nThe molars are not numerous in any Rodents ; the hare and rabbit (Lepus) have\n6\u20146\n5\u20145\n; i. e. six molars on each side of the upper\njaw, and five on each side of the lower jatf :\n5___5\nthe pika (Lagomys), has -\u2014- ; the squirrels\n\u00fc--\u00d6\nhave\n5\u20145\n4\u20144\n; the families of the dormice, the\nporcupines, the spring rats (Echingid\u0153), the octodonts, chinchillas, and cavies, have 4\t4\n^ molars ; in the great family of rats\n(Murid\u0153), the normal number of molars is 3__3\ng ^ ; but the Australian water rat (Hydro-\n2 2\nmys) has but ^\u2014\u2014 molars, making with the\nincisors twelve teeth, which is the smallest number in the Rodent order ; the greatest number of teeth in the present order is twenty-eight, w'hich is exemplified in the hare and rabbit ; but thirty-six teeth are developed in these species, six molars and two incisors being deciduous.\nIn all the Rodents, in which the number of molars exceeds three in a series, the additional ones are anterior to these, and are premolars, i. e. they have each displaced a deciduous predecessor in the vertical direction, and are what Cuvier calls dents de remplacement. This it is which constitutes the essential distinction between the dentition of the marsupial and the placental Rodent ; the latter, like the placental Carnivora, Ru-minantia, and ordinary Pachydermata having never more than three true molars. Thus the Rodents, which have the molar formula of 4,_4\nshed the first tooth in each series ; and\nthis is succeeded by a permanent pre-molar, which comes into place later than the true molars ; later, at least, than the first and second, even when the deciduous molar is shed before birth, as was observed by Cuvier in the Guinea-pig. In the hare and rabbit the three anterior teeth in the upper jaw, and the two anterior ones in the lower jaw, succeed and displace, in like manner, deciduous predecessors, and come into place after the first and second true molars are in use, and contemporaneously with the last molar.\nIt does not appear that the scalpriform incisors are preceded by milk teeth, or, like the pre-molars of the Guinea-pig, by uterine teeth ; but the second incisor was observed by Cuvier to be so preceded in the genus Lepus, and he has figured the jaw of a young rabbit, before that deciduous tooth was shed, when six incisors are present in the upper jaw. This condition is interesting, both as a transitory manifestation of the normal number of\nVOL. IV.\nincisive teeth in the Mammalia series, and as it elucidates the disputed nature of the great anterior scalpriform teeth. Geoffroy St. Hilaire contended that the scalpriform teeth of the Rodents were canines, because those of the upper jaw extended their fang backwards into the maxillary bone, which lodged part of their hollow base and matrix. But the scalpriform teeth are confined exclusively to the intermaxillary bones at the beginning of their formation; and the smaller incisors, which are developed behind them in our anomalous native Rodents, the hare and rabbit, retain their usual relations with the intermaxillaries, and, a fortiori, prove the tooth which projects anterior to them to be also an incisor.\nThe law of the unlimited growth of the scalpriform incisors is unconditional, and constant exercise and abrasion are required to maintain the normal and serviceable form and proportions of these teeth. When, by accident, an opposing incisor is lost, or when by the distorted union of a broken jaw the lower incisors no longer meet the upper ones, as sometimes happens to a wounded hare, the incisors continue to grow until they project like the tusks of the elephant, and the extremities, in the poor animal\u2019s abortive attempts to acquire food, also become pointed like tusks : following the curve prescribed to their growth by the form of their socket, their points often return against some part of the head, are pressed through the skin, then cause absorption of the jaw-bone, and again enter the mouth ; rendering mastication impracticable, and causing death by starvation. In the Museum of the College of\nFig. 269.\nIncisor teeth of the upper jaw of a Rabbit, showing the effects of unchecked growth on the scalpriform incisor (i), and the accessory incisor (i, 2).\nSurgeons there is a lower jaw of a beaver in which the scalpriform incisor has,by unchecked growth, described a complete circle ; the point has pierced the masseter muscle and entered the back of the mouth, passing between the condyloid and coronoid processes of the lower jaw, descending to the back part of the molar teeth, in advance of the part of its own alveolus, which contains its hollow root. The upper jaw of a rabbit with an analogous abnormal growth of the scalpriform and accessory incisors is represented in fig. 269.\nOrgans of digestion. \u2014The order of Rodent quadrupeds comprehends animals which are nourished by various kinds of food, both animal and vegetable substances forming the nutriment of some genera, whilst others live exclusively upon the fruit, bark, or leaves of\nc c","page":385},{"file":"p0386.txt","language":"en","ocr_en":"386\tRODENTIA.\ntrees, or upon tender succulent plants. The differences observable in the structure of the stomach and intestinal canal correspond to the variety of their food, and bear a relation to the structure of their dental apparatus.\nFig. 270.\nCheek pouches of the Canada Rat ( Geomys bursariusf\nSome genera, as, for example, the Canada rat (fig. 270.) are remarkable for the possession of capacious cheek pouches, in which considerable quantities of food can be stored up, and which, like the crop of birds, may be considered as reservoirs, wherein nutriment can oe retained preparatory to its introduction into the stomach.\nThe type of stomach most common in this order is the following : the stomachal bag is formed by two distinct pouches, which are more or less separated from each other ; one portion, situated to the left of the cardia, is placed longitudinally, and is generally of a cylindrical or conical shape. This portion is frequently larger than the right portion ; it is lined internally with a thick epidermis, which terminates suddenly, and clearly indicates by its margin the boundaries of this compartment of the stomach. The right compartment, which is situated more transversely and further back, is of a conical shape, the apex of the cone terminating at the pylorus. This second portion has its walls thicker and more muscular than the former ; its mucous membrane is not lined with epidermis, but presents the ordinary appearance. The distinction between these two portions is indicated externally by a constriction. The oesophagus enters the first compartment very near to the point where it communicates with the second.\nSuch may be said to be the typical form of the stomach in this extensive order, but many families recede from it to a greater or less extent.\nIn the squirrels (Sciurus) for example, the stomach is not divided into separate cavities, but is of a pyriform or oval shape, giving off a conical or cylindrical portion, which terminates in the pylorus. The first compartment is lined internally with a thick epidermis, which forms two oval lips, as it is prolonged around the opening into the second compartment, the lining membrane of which is simply mucous, without any apparent epidermic covering. The ondatras (Fiber, Cuv.),\ncampagnols (Arvicola), and the lemmings (Georychus, llinger), present a similar arrangement.\nFig. 271.\nStomach of the Water Vole (Arvicola amphibius).\ng, oesophagus ; a,f cardiac extremity of the stomach ; c, its median constriction ; b, dilated pyloric extremity of ditto ; e, pyloric pouch ; h, i, duodenum.\nIn the Hudson\u2019s Bay lemming (Mus Hud-sonius, Gm.), the shape of the stomach is slightly different, it is situated transversely and much elongated, without any division into cavities ; the cardia opens at about the upper third of its anterior border ; the left cul-de-sac is cylindrical and of uniform size with the pyloric portion, which is bent forward and to the left side.\nThe stomach likewise varies from the common type in the jerboa (Dipus, Gm.), and in the leaping hares of the Cape (Helamys). In the former it is globular, in the latter pyriform and longitudinal, with a large cardiac cul-de sac directed forwards, a pyloric cul-de-sac, and a short cylindrical pyloric portion, which is bent forwards.\nThe rat moles (Spalax, Guldensledt) are approximated to the lemmings and to the campagnols in the shape of their stomach, which is divided into two pouches, having the oesophagus closely approximated to the pylorus.\nIn the muscardin (M. avellenarius, L.) the stomach offers a peculiarity in its structure, which distinguishes it not only from the other species of this genus, but also from all other Mammalia, \u2014 the oesophagus immediately beyond the diaphragm terminates in a globular pouch, the walls of which are thick, glandular, and exhibiting internally numerous pores leading into crypts : this structure is separated by a constriction from the stomach properly so called. This latter organ forms a large cul-de-sac of a slightly oval shape, which gives off anteriorly, and to the right side, a short bowel-like pyloric portion. In this animal, therefore, there are two stomachs, one of which corresponds with the glandular stomach of birds, as will be seen further on. The beaver exhibits traces of this structure.\nThe stomach of the hamster (Cricetus, Cuv.) approximates the common type described above, the stomach being divided into two pouches, separated by a deep constric-tion ; the left pouch is cylindrical, the right globular. The cardiac orifice is situated in","page":386},{"file":"p0387.txt","language":"en","ocr_en":"RODEN TI A.\t387\nthe former to the right of its base, opening on the constriction itself, so that aliments can pass immediately into the second compartment by the assistance of a fold, which is prolonged from the cardia into this cavity ; and the pyloric oortion may be distinguished, which is more muscular than the rest, and terminates in the intestine by a slightly prominent pylorus.\nThe Cape mole (Bathiergvs, Iliger) likewise conforms to the preceding type of structure ; the left compartment of the stomach is of enormous size, elongated and pierced at its base by the cardiac orifice ; the left compartment is of smaller dimensions, of a globular form, and separated from the preceding, both by an external constriction and an internal fold of the mucous membrane. There are, moreover, two additional folds nearer to the pylorus, which seem to form a third compartment. The orycteres of the Downs (Bathiergus maritimus) has its stomach slightly different ; its position is more longitudinal, so that the left compartment is anterior, and the right posterior ; the pyloric portion short, cylindrical, and directed forwards.\nIn the beaver (Castor) the stomach is transverse and elongated in that direction, the right portion being larger than that which is situated to the left of the cardia ; the oesophagus is inserted into the first third of its anterior margin by a narrow opening, surrounded with pointed processes, which are analogous to the fringes formed by the epidermis in many other Rodents. At the point where it terminates around the opening of the first compartment of the stomach into the second, numerous largely developed culs-de-sac are distinguishable, which project more or less bevond the cardia in different individuals. On th\u00e9 right of this orifice commences the pyloric portion, the termination of which is indicated by an external constriction, and by an internal thickened ring. The pylorus is approximated very closely to the cardiac orifice. This pyloric portion, which is more muscular than the rest, is sometimes dilated into a distinct pouch, separated by a constriction from the pyloric cul-de-sac. The internal membrane presents every where the same appearance, except that in the pyloric portion it appears to be more smooth, and its folds take a different direction. On the right of the cardia there is a very thick fold, separating the left from the right compartment.\nIn the rabbit and the hare (Lepus, Lin.) the stomach is very much elongated, particularly in that portion which is situated to the right of the cardiac orifice. This latter portion forms a bulb, the muscular wall of which is thicker than elsewhere, especially in the vicinity of the pylorus, where it is swollen into a muscular ring. In the other parts of the stomach the existence of this layer is scarcely perceptible.\nIn the lagomys (Cuv.) we have again the common type of structure, as also in the agoutis and the pacas.\nIn the pteromys (F. Cuv.) the stomach is\nsituated more transversely, and the two culs-de-sac are more distinct ; the right compartment is the largest, and gives off at an angle a short conical pyloric portion.\nIn the sciuropteres (F. Cuv.) the stomach is round, deep from before to behind, and having the bottom of the cardiac culs-de-sac formed into a little pouch, and extending slightly beyond the cardia ; the pyloric portion is conical, very muscular, and lined internally with a yellowish mucous membrane, whilst the lining membane of the rest of the stomach is white and arranged in folds, which form arches parallel to the curvatures of the viscus. There are two other folds running longitudinally on the right and on the left of the cardia, but which probably do not exist when the stomach is distended : these would seem to indicate traces of a division of the cavity into three pouches.\nIn the dormice (Myoxus, 6m.) the stomach differs in shape in accordance with the appetites of the different species. In the common dormouse (Mus Glis, Lin.) it is conical, with a small pyloric portion directed forwards ; its membranes are thick and muscular, approximating the type of a carnivorous stomach.\nI n Myoxus Nit el a, on the contrary, it is globular, and consists of a single sac ; the crypts, the orifices of which open into the cavity of the stomach, form a thick disc in the vicinity of the cardia : these crypts are evidently small culs-de-sac, formed by the mucous membrane and the cellular layer beneath it, which here appear folded upon themselves in irregular festoons, when a section of this glandular disc is examined. The ligneous substances upon which the beavers feed, have rendered necessary this superabundance of the secretions furnished by this gland. A constriction separates the pyloric portion from the remainder of the straight part of the stomach. The pylorus consists of a prominent ring projecting into the intestine.\nIn the family of the porcupines (Hystrix, Lin.) we have another example of the differences which the stomach may present in different genera. In the cuendu (Synetheres, F. Cuv.) this viscus resembles that of the orycteres of the Downs, above described ; it is elongated, longitudinal, with one compartment anterior and the other posterior ; the oesophagus is inserted into the right side ; the cardia is placed far back, and approximated to the pylorus ; the pylorie portion is. short, cylindrical, and directed forwards, terminating by a ring, which projects into the intestine. In the European porcupine (Hystrix cristata, Lin.) the stomach is globular, forming from before to behind a deep and wide bag.\nIntestinal canal.\u2014The tract of the small intestines offers nothing remarkable in the Rodentia j its walls are very thin, and its diameter pretty even throughout. On coming to the large intestines, the most striking feature is the enormous size of the c\u00e6cum, which, in many genera, itself fills up a great proportion of the abdominal cavity. There are, moreover, many interesting modi-","page":387},{"file":"p0388.txt","language":"en","ocr_en":"388\tRODENTIA.\nfications to be noticed, both in the construction of the c\u00e6cum and of the commencement of the colon, which generally presents the same appearance as the c\u00e6cum itself for a short distance from its commencement.\nThe greater or less development of the c\u00e6cum is in relation to the nature of the food appropriate to each individual. In one genus only, namely, the dormouse (Myoxus), it is altogether wanting ; those Rodents that live upon grass and herbs have it most remarkably developed ; and in the hare it has been calculated that the capacity of the c\u00e6cum is ten times as great as that of the stomach itself. In the granivorous genera its size is likewise very considerable ; so that, in the hamsters, lemmings, Guinea-pigs, and allied genera it has been estimated to be four times larger than the stomach.\nAnother remarkable peculiarity may be observed in the c\u00e6cum of the Rodentia, namely, that it frequently has its cavity divided into regularly arranged cells disposed in several rows, or else forming a single series.\nIn other cases the cavity of the c\u00e6cum is divided into compartments by a broad spiral\nFig. 272.\nC\u00e6cum of the Squirrel.\na, termination of the small intestine ; b, d, the c\u00e6cum ; e, dilated commencement of the colon.\nvalve, as is the case in the hares ; or, as in the marmots, by circular folds of its lining\nStomach and intestinal canal of the Rat (3fus Rattus).\nf, oesophagus ; a, b, d, compartments of the stomach ; e, pylorus ; g, h, i, small intestine ; k, l, c\u00e6cum ; p, commencement of the colon ; m, n, colon ; o, anus.\nIt. is worthy of observation that in those species that have the c\u00e6cum most largely developed, that organ is furnished with very remarkable glandular appendages ; this structure is met with in the genera Lepus and Lctgomys.\nIn order to illustrate the above general description of the digestive organs of the order of quadrupeds under consideration, we shall select a few examples illustrative of the principal varieties which it presents in different genera.\nIn the squirrel (Sciurus) the small intestine (fig. 272. a) is nearly of the same diameter throughout ; the c\u00e6cum (b, c, d) is of moderate dimensions, of a conical shape, and destitute of any cells or partitions internally.\nmembrane. In some species again, as in the jerboa, &c., the interior of the c\u00e6cum is a simple cavity, without any division or internal complication. All these diversities of structure seem to be in relation with the different kinds of food devoured by these animals.\nThe proportionate length of the small intestine as compared with that of the large, is frequently the reverse of what holds good in carnivorous quadrupeds ; but the diameter of the latter, except in the immediate vicinity of the c\u00e6cum, is scarcely greater than that of the small intestine (fig. 273. m, ri).\nThe intestinal villi have the shape of leaflets of fringed lamin\u00e6, or sometimes of very fine filaments ; the entire inner surface of the small intestine is villous, whilst that of the large intestine is quite smooth.","page":388},{"file":"p0389.txt","language":"en","ocr_en":"RODENTIA.\nThe colon (e) is for a short distance almost of the same diameter as the c\u00e6cum, but it soon diminishes in size, and throughout the rest of its extent is scarcely wider than the small intestine. Internally, it presents no septa or valvul\u00e6 conniventes. The intestinal papill\u00e6 form small lamellae, the borders of which are fringed with delicate filaments ; these papill\u00e6 extend throughout the v/hole length of the small intestine, but towards its termination becomes smaller and less perceptible.\nIn the rats, the alimentary canal would be nearly of the same calibre throughout, were it not for the interposition of the c\u00e6cum between the ileum and the colon. The c\u00e6cum in this family of Rodents rather resembles a second stomach {fig. 273. k, /) than a bowel ; it is capacious, short, and slightly curved upon itself, but without any constrictions, tapering gradually towards its blind extremity. The walls of the intestinal canal are throughout thin, delicate, and transparent ;\nFig. 274.\nC\u00e6cum of the Water Vole (Avicola amphibius').\nI, m, end of the small intestine ; n, o,p, q, c\u00e6cum ; r, dilated commencement of the colon ; s, point at which the colon becomes contracted.\n389\nbut slight traces of a spiral valve are visible at the commencement of the colon.\nIn the water-rat (Arvicola amphibius) the small intestines are of equable diameter throughout their whole extent, but their calibre is small, as indeed is that of the large intestine. The c\u00e6cum is, however, of enormous proportions (fig. 274. n, o, p, \u00e7), and is divided at intervals into pouches by deep constrictions. The commencement of the colon (f) is extremely voluminous, but it soon diminishes in its diameter, and is twisted in a remarkable manner, so as to form several close spiral turns ; the walls of the small intestine (/, m) are very thin and transparent ; at the commencement of the colon its lining membrane is thrown into regular folds, which, as they appear through the transparent coats of the intestine, resemble a series of spiral muscular fibres.\nIn other species belonging to the genus arvicola, the same disposition is observable.\nIn the Cape moles (Bathiergus) the structure of the c\u00e6cum varies. In the orycterus of the Downs (Bathiergus maritimus) the c\u00e6cum is short, and has its walls sacculated and puckered up, as it were, by tendinous bands. The colon begins by a wide pouch, and preserves through nearly its whole length a considerable diameter and sacculated appearance, but on approaching the anus it becomes contracted and of equable diameter.\nIn the white-spotted orycterus (Bathiergus capensis) the c\u00e6cum is much longer in proportion and of more equal calibre, although still very wide, in proportion to the size of the small intestine, and much sacculated; the commencement of the colon is at first of the same diameter as the c\u00e6cum, but it soon becomes narrower and spirally convoluted, much in the same way as in the water-rat.\nIn the hare and in the rabbit the small intestine is nearly of the same diameter throughout its whole length ; the c\u00e6cum is of a very remarkable size, and forms an enormous elongated conical sac, divided, at intervals, by deep constrictions into numerous compartments, as far as about the distance of two or\nFig. 275.\nC\u00e6cum of the Hare.\nc, termination of the ileum -, a, d, a spirally convoluted c\u00e6cum ; b, d, its terminal^en^o\u00c4'colo\u00a3 dilated pouch, close to the termination of the small intestine; c, capacious commencement ot the colon\nwhich, at g, becomes considerably diminished in size.\tC C 3","page":389},{"file":"p0390.txt","language":"en","ocr_en":"RODENTIA.\n390\nthree inches from its extremity {fig. 275.). The constrictions, apparent externally, correspond to the windings of a spiral valve, which runs nearly along the whole length of its cavity. The small intestine, at the point where it is about to enter the colon, dilates into a cavity (/), the walls of which are thick and glandular. At its commencement (e) the colon is quite as capacious as the c\u00e6cum, but it soon begins to contract in its diameter, (g) At its commencement there are three rows of sacculi, divided by as many tendinous bands, but further on these sacculi disappear. The rectum is much dilated, and contains, at intervals, small pellets of excrement moulded in the sacculi of the colon. In all the species belonging to this genus, as well as in the rats and hares, including the Lagomys, the extremity of the caecal bag, opposite to that which receives the termination of the small intestine, is terminated by a long, smooth, cylindrical appendage {fig. 275. d, b) the walls of which are glandular, and somewhat resemble those of the glandular stomach of a bird.\nThe above examples will suffice to put the reader in possession of the general structure of the alimentary canal in the rodent order of quadrupeds ; and for farther details we must refer him to the last edition of Cuvier\u2019s Le\u00e7ons d\u2019Anatomie compar\u00e9e, where the principal varieties met with in the different genera are recorded.\nLiver.\u2014In the Rodentia the liver is very largely developed, and presents the usual division into five principal lobes. The gallbladder, though generally present, is sometimes wanting, a circumstance more particularly observable in the family of rats. Another circumstance which may be noticed is that the bile is frequently poured into the intestine at a point remote from that where the pancreatic fluid enters it ; when such is the case, the biliary secretion enters the duodenum very near to the pylorus, above the entrance of the pancreatic duct.\nIn the porcupine the ductus communis choledochus is formed by the union of two hepatic canals with the cystic duct; it enters the intestine close to the pyloric ring, opening into a furrow excavated in the latter, in such a manner that the bile would seem to flow as easily into the stomach as into the duodenum. The opening of the pancreatic canal is at a considerable distance from the pylorus.\nThe pancreas is very large, and generally divided into two portions.\nThe spleen occupies its usual position suspended from the stomach by the gasfro-splenic omentum.\nThe lymphatic system of the Rodentia conforms in all respects to the usual arrangement of these vessels met with in other quadrupeds, and exhibits nothing worthy of particular remark.\nThe arterial system, as far as the general distribution of the blood-vessels is concerned, offers' a few peculiarities worthy of notice. In all those genera of rodent quadrupeds which become dormant during the winter\nmonths, the vertebral artery considerably surpasses in size the internal carotid ; to such an extent, indeed, that some authors have described the latter vessel as being entirely wanting. In this case the basilar artery forms by itself a very considerable part, and sometimes the whole of the circle of Willis, giving off the anterior cerebral arteries as well as the posterior arteries of the brain.* The arrangement of the carotids, moreover, varies remarkably in different genera.\nIn the beaver the internal carotid is larger than the vertebral.\nIn the porcupine the internal carotid, after following for some distance the direction of the internal maxillary, without undergoing any sinuous flexures, enters the cranium through the foramen lacerum anterius, where it immediately joins with the basilar, which surpasses it in size, to form the circle of Willis.\nIn the Guinea-pig and the agouti there is, properly speaking, only an external carotid, of which the internal carotid is but a small branch. This little cerebral branch is derived from the internal maxillary, of which it seems to be a continuation ; it enters the cranium through the foramen ovale of the sphenoid bone, and joins the circle of Willis, which is here principally formed by the vertebral artery.\nIn the squirrel the internal carotid- enters an osseous canal in the tympanum, through the jugular foramen, passes between the crura of the stapes, and then penetrates the cranium through a hole in the petrous portion of the temporal bone ; it there divides into two branches, the smaller of which enters a deep groove in the os petrosum, issues from the cranium through the foramen lacerum anterius to enter it again through the oval foramen of the sphenoid bone. It is only after all these windings that it divides into small branches, and of these only one or two go to form the circle of Willis, the rest being meningeal arteries. The continuation of this branch subsequently becomes the representative of a portion of the ophthalmic artery. The other branches usually given off from the ophthalmic artery are derived from the second branch of the internal carotid above mentioned, which previously gives off branches to the dura mater. It will thus be seen that the internal carotid supplies very little blood to the brain, and this blood only arrives at its destination by a very circuitous route, f\nIn the marmot the internal carotid at first follows the same course as in the squirrel ; it enters the canal of the tympanum through the jugular foramen, and then traverses the opening between the crura of the stapes, after which it divides into two branches : of these the internal, which is the smallest, runs\n* Vide Memoire sur les vaisseaux c\u00e9phaliques de quelques mammif\u00e8res qui s\u2019en courdissent pendant l\u2019hiver, par M. Otto, Annales des Sc. Natur, t. xi.\np. 200.\nt Vide Barkow, Disquisitiones circa originem et decursum arteriarum animalium. Lipsi\u00e6, 1829.","page":390},{"file":"p0391.txt","language":"en","ocr_en":"RODENTIA.\t391\nthrough an ascending canal, which enters the cavity of the skull close to the sella turcica, arriving at the brain much in the same manner as the internal carotid of the human subject. This branch is smaller than the vertebral artery. The other or external branch enters the cranium through a canal that opens upon the anterior surface of the petrous bone, and divides into the middle meningeal and ophthalmic arteries.\nIn the dormouse the distribution of the internal carotid very nearly resembles what is described above, as occurring in the squirrel and in the marmot. In some genera of Rodents the internal condyle of the os humeri is perforated by a canal through which the ulnar artery passes in company with the median nerve : this arrangement exists in the squirrel, the hamster, and the helamys.\nVenous system. \u2014 In most of the Rodentia, instead of a single anterior vena cava, there are two principal anterior trunks of the venous system, one of which, namely the right, occupies the usual position of the vena cava anterior, whilst the left runs along the furrow that separates the base of the ventricle of the heart from the left auricle, to reach the right auricle, into the upper and left side of which it opens.\nIn those genera which hibernate the external jugular vein likewise presents a very remarkable arrangement. This vein receives a considerable proportion of the blood derived from the brain through a wide canal, situated between the os petrosum and the temporal bone, into which the anterior division of the transverse sinus opens, so that it is only the smallest moiety of blood derived from the vein which escapes through the jugular foramen into the internal jugular.. The vertebral vein likewise communicates with the external jugular, carrying off its share of the blood from the interior of the cranium.\nFig. 276.\nUpper surface of the brain of the Porcupine.\n(After Serres.')\na, medulla spinalis ; b, hemispheres of cerebellum ; c, median lobe of the cerebellum ; d, e, k, l, cerebral hemispheres.\nAlthough this disposition of the cerebral veins is common to all hibernating animals, as Cuvier very justly remarks, it is by no means peculiar to quadrupeds that pass the winter in a state of torpor ; on the contrary, it is met with in many Rodents that do not hibernate ; as, for example, in the rats ; it also occurs in the horse, as well as in many Edentata, Ru-minantia, and Carnivora. Cuvier believes this arrangement to be in relation with the situation and direction of the head, the difference between these quadrupeds and man rather depending upon the position of the latter standing on four legs, than upon any cause connected with the habit of hibernation.\nNervous system. \u2014 The brain in the Rodent order of quadrupeds presents two principal forms ; in the feebler, and more strictly herbivorous species, such as the hare, the rabbit, the agouti, paca, &c., it presents a great resemblance externally in its shape to that of birds, the cerebral hemispheres being broad behind, and gradually tapering towards the anterior lobes. In others, such as the beaver, porcupine, capromys, &c., the contour of the brain is nearly circular (flg. 276.), as in carnivorous quadrupeds. Between these extreme forms there are, however, intermediate gradations, such as are met with in the squirrel, the marmot, the water-rat, and others.\nFig. 277.\nBase of the brain of the Porcupine (Histrix cristata').\n(After Serres.')\na, anterior pyramid, exhibiting the interlacement of their internal fasciculi ; o, olivary bodies ; t, trapezoid bodies; p, pons Yarolii; h, the lobe of the hippocampus ; g, middle portion of the hemisphere ; r, olfactory tract ; x, external root of olfactory lobe ; y, internal root of ditto. The nerves are indicated by corresponding numbers.\nThe most striking circumstance presented by the brains of these animals is the almost complete deficiency of cerebral convolutions. The hemispheres are almost completely smooth upon their surface, presenting only a few shallow lines instead of the numerous sulci which characterise the brain of the Carnivora.\nc c 4","page":391},{"file":"p0392.txt","language":"en","ocr_en":"RODENTIA.\n392\nThe cerebellum is of moderate proportions, and is scarcely at all overlapped by the posterior lobes of the cerebrum.\nFig. 278.\nUpper surface of the brain of the male Agouti.\n{After Serres.)\na, the medulla spinalis ; b, posterior pyramid ; c, median lobe of the cerebellum ; d, hemisphere of cerebellum ; e, cerebral hemispheres ; f olfactory lobe of the brain.\nOn separating the hemispheres, the tuber-cula quadrigemina {fig. 280. 8, 9) are seen to be of very large size ; and, what is re-\nFig. 279.]\nBase of the brain of the male Agouti. (After Serres.)\np, pons Yarolii ; h, lobe of the hippocampus ; g,f lateral portion of cerebral hemisphere ; k, anterior part of the lobe of the hippocampus ; e, olfactory lobe ; u, infundibulum. The nerves are indicated by corresponding numbers.\nmarkable, the anterior pair {nates') are of a roundish form, and much larger than the pos-\nterior pair {testes) (8) ; a circumstance which is the converse of what exists in carnivorous quadrupeds. In other respects the structure of the brain in the Rodentia offers no peculiarity worthy of special notice.\nThe organs of the senses conform strictly in their anatomical structure to the general type common to mammiferous quadrupeds, and consequently need not occupy our attention in this place.\nFig. 280.\nInterior of the brain of the same animal. {After Serres.)\na, medulla spinalis ; b, restiform body ; c, arbor vit\u00e6 cerebelli ; 1, 2, 3, 4, 5, 6, ramifications of ditto ; d, superior peduncle of the cerebellum ; 7, nervus patheticus ; 8, posterior quadrigeminal tubercle ; 9, anterior quadrigeminal tubercle; 11, optic tract; 12, posterior pillar of the fornix ; 13, corpus striatum ; n, corpus callosum ; i, f g, horizontal section of the hemisphere on a level with ditto ; l, m, lateral portion of the cerebral hemisphere.\nThe structure of the kidneys, and the general disposition of the urinary apparatus afford nothing deserving particular description.\nMale organs of generation.\u2014 The Rodentia are amongst the most prolific of all quadrupeds ; a circumstance which may, perhaps, account for the extraordinary development of the appendages to the male generative system, which are met with throughout the order. It is, indeed, difficult to identify the precise analogies of some of the accessory genital organs, which are much more complex in structure than those of other Vertebrata.\nIn the greater number of Rodents, as for instance in the rats, the Guinea-pigs, the agoutis, the porcupines, the beaver, the ondatra, and the squirrels, the testicles are not contained in a scrotum, but during the season of impregnation are lodged beneath the skin of the perineum, which is tightly stretched over them. In the hares, however, two distinct scrotal pouches exist {fig. 281. k, l), situated in the vicinity of the anus, in which","page":392},{"file":"p0393.txt","language":"en","ocr_en":"RODENTIA.\nthe testes are contained. The testes are moreover, remarkable for tneir great size,\nFig. 281.\n\u00ab I\nMale generative organs of the Hare.\na, glans penis ; b, body of penis ; c, prostate gland ; d, vesicul\u00e6 s\u00e9minales ; e, the urinary bladder ; f g, testicles; h, i, epididymis; k, l, the two scrotal pouches ; p, q, vasa deferentia.\nwhich generally exceeds that of the kidneys ; a circumstance which is more remarkably evident during the season of copulation.\nFrom the testicles situated as above, the vasa deferentia ascend into the abdominal cavity, along with the spermatic vessels, through the external abdominal ring. In some tribes, a little above their insertion, the walls of the vasa deferentia become manifestly thicker, and the cavity of their duct considerably dilated ; in some cases they join together, and seem to form but one canal ; but this appearance is merely external, the ducts continuing separate throughout their whole length.\nThe vesicid\u0153 s\u00e9minales, or their analogues, exist in all the Rodentia. In the hares they are simple bags {fig. 281. rf); but, generally speaking, their cavity is more or less convoluted, or branched out into caeca, as, for example, in the agouti (fig. 282. i, i), and in the beaver (fig. 284. o,p). In most of the genera of this order of quadrupeds the vesicul\u00e6 s\u00e9minales are remarkable for their great development ; in the Guinea-pig they form two long conical tubes, which taper much towards their extremities, but are slightly sacculated for a portion of their length ; the excretory ducts in this animal open into the urethra by an orifice common to them, and to the vasa deferentia.\nIn the agouti each opens separately into the common cavity of the verumontanum, in which are also situated the separate orifices of the vasa deferentia, and of the excretory canals of the accessory vesicles ; so that ail\n393\nthese canals are brought into communication by means of this chamber.\nIn the Alpine marmot, the vesicul\u00e6 s\u00e9minales contain internally a very complicated cavity, the walls of which are glandular.\nIn the rats, properly so called, the vesicul\u00e6 s\u00e9minales consist of large membranous bladders of a flattened conical form, with their inner margins sacculated and uneven, something like a cock\u2019s comb. In these animals they are in great part situated out of the pelvis on account of their very la ge size ; in the hamsters, the voles (Arvicol\u0153), the dormice, and the jerboas they present a similar structure, and become remarkably developed during the season for copulation.\nFig. 282.\nThe generative organs of the male Agouti.\na, a stylet introduced into the cul-de-sac, at the extremity of the penis; b,b, serrated bony plate, situated on each side of the glans penis ; c, c, vasa deferentia ; d, the body of the penis ; e, e, the prostates ;/, canal of urethra laid open ; g, h, a style introduced through the prostatic duct into the urethra ; i, i, the vesicul\u00e6 s\u00e9minales ; l, m, a wire passed along their duct k, into the urethra ; o, o, Cowper\u2019s glands, communicating with the urethra by means of the duct, p, into which a style q has been passed ; n, the anus ; r, anal gland with the style, s, t, passed into its duct.\nIn the hare and in the rabbit these organs are represented by the single sac already alluded to (fig. 281. d), the size of which is considerable ; this sac is of a triangular shape, two of its three corners being sometimes considerably elongated ; its walls are membranous, except for about two thirds of its upper side, where they are formed by a thick glandular substance something resembling in texture the prostate gland. This sac opens into the urethra by a single orifice excavated in the centre of the verumontanum, which receives","page":393},{"file":"p0394.txt","language":"en","ocr_en":"394\tRODENTIA.\nlikewise the terminations of the two vasa defe-rentia.\nIn the lagomys {Lepus pusillus, ogotonus, and alpinus, Pall.) the vesicul\u00e6 s\u00e9minales are double and separate.\nIn the common squirrel each seminal vesicle consists of a short canal folded upon itself. This approximates its fellow on the opposite side between the prostate and the canal of the urethra ; and, contrary to what is usual in this order, internal to the vasa deferentia.\nThe prostate glands. \u2014 The name of prostate gland is restricted by Cuvier to those glandular masses of analogous structure to the human prostate, the excretory canals of which open by one or several orifices into the commencement of the muscular portion of the urethra, or into the first portion of that canal. In some cases, however, the representatives of the prostate are made up of numerous ramified and complicated tubes, in which case they are called tubular prostates. In the hare and the rabbit, this gland is represented by the glandular mass, which, as above described, forms a portion of the walls of the vesicul\u00e6 s\u00e9minales, and which extends for some distance upon the muscular portion of the urethra\n(fig- 28 L c)\u2019\nFig. 283.\nMale organs of the Water Vole ( Arvicola amphibius').\na, glans penis ; c, the urinary bladder ; d, e, the testicles ; f, g, epididymis, situated at some distance from the testes ; k, l, vesicul\u00e6 s\u00e9minales ; m, n, o, p, q, r, the prostates ; s, the rectum, the extremity of which is surrounded by a glandular mass, t, from which a milky fluid is poured into the rectum in the vicinity of the anus, v.\nIn the Alpine marmot it forms a considerable mass situated above the commencement of the urethra, divided posteriorly into two roundish lobes.\nIn the squirrel the prostate gland is as long as the muscular portion of the urethra, to\nwhich, however, it is only adherent at the two points where its excretory ducts penetrate that canal ; in this animal its shape is oval, flattened above, and bilobed posteriorly.\nIn the agouti the prostates {fig. 282. e, e) assume the tubular form, each gland being composed of a common trunk, divided into branches and ramusculi, ending in vascular enlargements.\nIn the numerous family of rats, the prostates are represented by several packets of ramified tubes, situated around the commencement of the canal of the urethra. Two others are connected with the inferior surface of the vesicul\u00e6 s\u00e9minales : these consist of a principal trunk, which has but few ramifications. These latter organs exist likewise in the lagomys, and may perhaps be considered accessory seminal vesicles.\nThe Guinea-pig is furnished with numerous ramified and convoluted tubes, connected together by a loose cellular tissue,which occupy the situation of the prostate gland ofother quadrupeds.\nFig. 284.\nGenerative organs of the male Beaver.\na, opening common to the rectum and the urethral canal ; b, the prepuce ; c, glans penis enclosed in the prepuce ; d, body of the penis ; e, f, g, h, i, k, preputial glands ; l, bifurcation of corpus caverno-sum forming the bulb ; m, n, Cowper\u2019s glands ; o,p, vesicul\u00e6. s\u00e9minales ; q, urinary bladder ; r, s, testicles ; t, v, vasa deferentia.\nCowper\u2019s glands. \u2014 Most of the Rodentia are provided with accessory glands, which, in situation at least, correspond with those called the glands of Cowper in the human subject.\nIn the male Agouti, these glands are two round, flattened, and very vascular bodies {fig. 282. o'), which open into the bulb of the urethra by separate ducts (p). In the Guinea-pig their structure is similar, as like-","page":394},{"file":"p0395.txt","language":"en","ocr_en":"RODENTIA.\n395\nwise in the beaver, only they are of much smaller proportionate size.\nIn the squirrel, Cowper\u2019s glands are represented by two large conical bladders twisted upon themselves, the summits of which are evidently of a glandular nature, and are divided internally into numerous small cells. Each of these organs opens by a large orifice into a cul-de-sac, which occupies the interior of the bulb of the urethra, and which is prolonged into a canal, that, becoming gradually narrower, opens into the urethra near the angle formed by the bend of the penis. The walls of the conical bladders, which constitute the substance of these glands, contain muscular fibres, which serve to constrict their cavities. In the Alpine marmot and in the boback, these glands present a similar structure.\nIn the rats they are of very large size and of a pyriform shape, their substance being enveloped in an aponeurotic sheath.\nPenis. \u2014 The penis in the Rodentia is differently arranged in different genera. In the Guinea-pig and the agouti, this organ, after running forwards in the ordinary manner as far as the anterior margin of the symphysis pubis, bends back again upon itself beneath the skin of that region towards the anus, so that the opening of the prepuce is situated very little in front of the anal orifice. Muscular fibres, derived from the cremaster muscles, are inserted into the penis near its curvature ; and others, derived from the external oblique muscle of the abdomen, are connected with the same point. The former probably contribute to effect the protrusion of the penis from its sheath, whilst the latter draw it back again into its concealment.\nIn the marmot, the penis, when it arrives in the sub-pubic region, does not bend back again to approximate the anus, but curves directly downwards ; in which position it is retained by ligamentous attachments.\nIn many genera of Rodents, as, for example, in the rats, the voles, the dormice, the jerboa, the hares, and the lagomys, the penis, after issuing from the pelvis, does not run forwards beneath the symphysis of the pubis, but passes directly backwards towards the anus, immediately in front of which the orifice of the prepuce is situated (fig. 281. a).\nIn most of the Rodentia the penis contains a bone, imbedded in the substance of the corpus cavernosum. But the most remarkable part of the penis in the order before us, is the glans, which in many species is armed with such a formidable apparatus of spines, saws, and horny spikes, that it must indeed be a rather stimulating instrument of excitement.\nIn the Alpine marmot it is conical, and terminated by a sharp point, formed entirely by the extremity of the os penis. On the right of this point is situated the opening of the urethra, and on the left there is a small but deep cul-de-sac.\nIn the common rat, the extremity of the penis, in its relaxed state, resembles a second prepuce, there being here a wide cavity exca-\nvated in the centre of the glands, enclosing a bone, the extremity of which projects beyond it, and is furnished with two small, cartilaginous, lateral appendages. Beneath this is situated the cavity of the urethra. Most of the genera allied to the rats, such as the hamsters, the voles, the dormice, &e., have their penis constructed upon the same plan ; but in some the surface of the glans is smooth, whilst in others it is covered with papillae, or studded with fine hairs.\nThe glans penis of the beaver is cylindrical in shape, but flattened at its extremity, which is studded with large papillae, the orifice of the urethra being situated near its centre.\nIn the Guinea-pig, the penis is supported by a flat and slightly curved bone imbedded in its upper portion, which reaches as far as the extremity of the glans above the canal of the urethra. Behind and below the termination of the urethral canal is a wide pouch, in the bottom of which are lodged two long cartilaginous horns. This pouch, during erection, is everted, so that the horns protrude externally. Two tendons are connected with the bottom of this pouch, which run along the penis inferiorly, and are connected with a thin layer of muscular fibres, derived from the bulb of the urethra and the rami of the corpora cavernosa. These tendons, either by their own elasticity, or by the action of the muscular fibres connected with them, serve to invert the pouch and draw it back again within the glans. The whole surface of the glans is covered with corneous scales, which, with the two horns above mentioned, give it a formidable appearance.\nFig. 285.\nPenis of the spotted Cavy ( C\u0153logenys suhfusca).\n(Fred. Cuv.)\nYet even this is an innocent weapon when compared with the penis of the agouti and other allied genera, which, besides containing a pouch inclosing strong horny spikes like that of the Guinea-pig, has the whole surface of the glans covered with sharp recurved","page":395},{"file":"p0396.txt","language":"en","ocr_en":"ROTIFERA.\n396\nspines, and is, moreover, provided on each side with a broad plate of horn, adherent to the glans by its inner border, while all its outer free edge is armed with strong sharp teeth resembling those of a saw (fig. 285.) ; a structure which is additionally remarkable from the circumstance, that in the females of the species thus barbarously armed, the vagina offers no peculiarity in its appearance.\nIn connection with the male organ of generation may be noticed the preputial glands, which, in some of the Rodentia, are very largely developed. This is more especially the case with the beaver, in which animal they secrete the drug castoreum, once much used in medicine. These glands form\nFig. 286.\nPreputial glands of the Beaver.\na, the prepuce laid open ; c, attachment of the prepuce around the neck of the penis ; d, body of penis ; e, e, opening of the inferior preputial glands ; f, i, m, stylets passed into the ducts of these glands ; h, l, o, the glands which on the right side are laid open, to show their internal structure ; p, superior large glandular sac ; r, ditto of the opposite side, laid open to show its interior ; q, opening of these sacs into the preputial canal.\nseveral wide pouches (fig. 284. e,fi g,h, i, k), situated on each side of the perputial sheath. The structure of these glands is shown in fig. 286. ; they are arranged in two sets, of which the lower, three in number on each side (h, /,o), are found when opened, as represented on the right hand side of the figure, to be hollow, the walls enclosing their central cavity being made up of numerous small glandular masses, that secrete a thick yellowish fluid. The upper set consists of two capacious bags (p), which, when opened, are seen to have their lining membrane (r) deeply rugose. The secretion of these pouches is of a deep grey colour, and, if possible, more disagreeable.\nFemale organs of generation. \u2014 The ovaria in the female Rodents occupy the same position as in other Mammifera, and are chiefly\nremarkable on account of the prominence and number of the ova which they contain, giving\nFig. 287.\nGenerative organs of the female Hare.\na, vulva ; b, vagina ; c, orifice of the urethra ; d, urethra ; e, f cornua uteri; g, termination of the cornua uteri by two separate orifices (ora uteri), into which the probes, h, i, have been introduced ; k, l, the ovaria ; n, o, Fallopian tubes ; p, the anus ; q, anal gland ; r, cavity situated between the vulva, a, and the rectum, s.\nthem a somewhat racemose appearance. The uterus is always deeply divided into two long cornua, and this division is in some cases carried to such an extent that the body of the uterus constitutes but a very insignificant part of this viscus, and is even absolutely wanting, as, for example, in the hare and in the rabbit, in which animals the cornua uteri open separately into the upper part of the vagina, so that the uterus is literally here double, as represented in the appended figure (fig. 287.), where two probes (h, i) are introduced into the two distinct openings, whereby the two cornua uteri communicate with the vagina.\nThe vagina presents no peculiarity of structure, even in the females of those genera in which the penis of the male is furnished with the remarkable armature described above.\nThe mammary glands in the Rodentia vary much in number, some, as the agouti, having as many as from twelve to fourteen nipples ; whilst in others, such as the Guinea-pig, there are but four.\n(T. Rymer Jones.)\nROTIFERA, or ROTATORIA, the name of a class of invertebrate animals which are characterised by the absence of a medullary chord and pulsating vessels ; by the possession of a simple tubular alimentary canal ; a definite form ; a reproduction neither fissiparous nor gemmiparous ; the reproductive organs of both sexes in the same individual. Their movements are effected by peculiar rotating organs, and they have no true articulated feet, but mostly a single false foot. The creatures thus constituted are often called wheel-animalcules, from the wheel-like motion","page":396},{"file":"p0397.txt","language":"en","ocr_en":"ROTIFER A.\t397\nof their ciliated rotatory organs. They were formerly classed together with the polygastric animalcules (Polygastria), under the common name of Infusoria, on account of their frequent presence with these animals in vegetable infusions. Recent researches, more especially those of Ehrenberg, have shown that the Rotifera possess a much higher and more complicated organisation than the Polygastria ; so much so, that in any linear arrangement of the animal kingdom, if the Polygastria were regarded as the lowest beings, several classes might properly intervene between them and the Rotifera. We shall, however, see that there are transitionary forms from the lower to the higher family, sufficiently indicative of their relations and the common circumstances under which they are produced.\nFor the discovery, and our knowledge of the structure, of the Rotifera, as well as the Polygastria, we are almost entirely indebted to the use of the microscope. Although, generally, the former creatures are much larger than the latter, they were not discovered till after the Polygastria. We are, however, indebted for the first observation of both the one and the other to the sagacity of the same great observer Leeuwenhoek, who, in 1675, first saw the Vorticella convallaria, and, in 1702, described the Rotifer vulgaris. Previous to this period, no accurate knowledge of creatures so small existed, although the speculations of Plato and the older Greek philosophers, subsequently followed up by Descartes, on the doctrine of living atoms, indicated that the human mind had already felt the possibility of the existence of such conditions of organic matter. Aristotle, too (Hist. Anim. v. c. 19.), as Ehrenberg has pointed out, was not unaware of the fact, that coloured water was produced by worms of some kind, which would seem to indicate a knowledge of the existence of some of the forms of Infusoria.\nAs the discovery of the first Rotifer must be regarded as an era in the history of zoology, we give it in the words of Leeuwenhoek himself:\u2014\u201c On the 25th of August I saw in a leaden gutter, at the fore part of my house, for the length of about five feet, and the breadth of seven inches, a settlement of rain water which appeared of a red colour. ... I took a drop of this water which I placed before the microscope, and in it I discovered a great number of animalcules. Some of them red, and others of them green. The largest of these viewed through the microscope did not appear bigger than a large grain of sand to the naked eye, the size of the others was gradually less and less : they were for the most part of a round shape ; and in the green ones the middle part of their bodies was of a yellowish colour. Their bodies seemed composed of particles of an oval shape ; they were also provided with certain short and slender organs, or limbs, which were protruded a little wav out of their bodies, by means of which they caused a kind of circular motion and current in the water : when they were at rest, and fixed themselves to the\nglass, they had the shape of a pear with a short stalk. Upon more carefully examining this stalk, or rather this tail, I found that the extremity was divided into two parts, and by the help of these tails, the animalcules fixed themselves to the glass ; the lesser of these appeared to me to be the offspring of the larger ones.\u201d This animalcule, which was the Rotifer vulgaris, is so accurately described by Leeuwenhoek in the same paper, as to leave little to be added by future describers. Subsequently to the time of Leeuwenhoek, who in addition to the Rotifer vulgaris discovered the Melicerta ririgeus, a number of species were described by Joblot, Hill, Baker, R\u00f6sel, Brady, and others; so that, in 1824, Bory St. Vincent was enabled principally, from the writings of others, to describe eighty species. Up to this time no distinction had been made between the wheel and other animalcules as a class. This separation was effected by Ehrenberg, who has not only examined the structure of these creatures with great care, but has added many new species to the list. In his work on infusory animalcules, he describes 189 species in fifty-five genera and eight families.\nThe Rotifera, undoubtedly, deserve to be called Infusoria as much as the Polygastria, as they are found very generally with the latter in various kinds of infusions. There are some circumstances, however, under which the Polygastria are developed, in which no Rotifera have yet been found : thus the Polygastria have been found inhabiting water, containing sulphuretted hydrogen and other gaseous constituents, where no Rotiferous animalcules have been found at all. As a general statement, it is true that the Rotifera are the last to appear in infusions ; but there are many instances in which Polygastria are developed without the subsequent appearance of Rotifera, and they disappear from infusions sooner than the former. Of the 722 species of Infusoria, described by Ehrenberg, he found that forty-one only were commonly present in the various artificial infusions, which he made in various parts of the world. Of these only three species belonged to the class Rotifera, viz. Co-lurus uncinatus, Icthydium podura, and Lepa-della ovalis. It is the appearance of these animalcules in infusions, which among other things have led to the question of equivocal generation (Generation) ; but whatever ground the low organisation of some of the Polygastria might afford for a belief in this doctrine, the Rotifera have an organisation too high to allow of doubt on this point. The fact of creatures so highly developed being produced in infusions, would create a doubt with regard to the whole theory of equivocal generation, which only positive observation could set aside.\nThe Rotifera, although classed with the Polygastria as \u201cinfusory animalcules,\u201d must not be regarded as performing a common function with them in the economy of creation, for not only are there fewer species of Rotifera, but they also exist in much smaller numbers.","page":397},{"file":"p0398.txt","language":"en","ocr_en":"398\nROTIFERA.\nWhilst the Polygastria descend in structure to a point where it may be well questioned, whether they partake most of the animal or vegetable character, the Rotifera have always a decided animal character. The Polygastria are even said to perform functions, such as the absorption of carbonic acid and the evolution of oxygen, which would seem to throw doubt on their animality altogether ; but no such function can possibly be attributed to the Rotifera. They appear to be distributed as widely on the earth as the Polygastria; and Ehrenberg has recorded their existence in various parts of Europe, Asia, and Africa. They have also been found in America. They inhabit both salt water and fresh, although the species which inhabit the latter are by far the most numerous. Like some of the higher animals, the same species are found inhabiting both salt and fresh water, whilst others are peculiar to brackish water. Although they are capable of pursuing their way in the open water, they are generally found swimming around, or attached to, the leaves and other parts of aquatic plants. In our own country the leaves of Ceratophyllum are found to be a favourite resort of species of Limnias, Masti-gocerca, Dinocharis, Monura, and others. The floating roots of the various species of Lemna are also the favourite resort of several species, whilst others are found in abundance amongst the fibrilliform fronds of the fresh-water algae. Some of them even take up their residence in the interior of the cells of plants. Roper first discovered them in the cells of Sphagnum obtusifolium. Subsequently Unger described a peculiar movement in certain tubercles which he had observed to be developed upon the stalk of Vaucheria clavata. The same phenomenon was witnessed by Professor Morren, of Liege, who, on investigating the subject more closely, found that the movements of the tubercles was due to the presence in their interior of the Rotifer vulgaris. Others, again, are found in turfy and bog waters ; whilst some, especially the species of Notommata, are found parasitic upon other animals.\nThe Rotifera are more susceptible to the influence of either high or low temperatures than the Polygastria. Ehrenberg observed the latter constantly come to life after the water in which they were contained had been frozen. Species of Diglena, Metopidia, Colurus, and Lepadella frequently came to life after they had been frozen for a short time. Other species experimented on, as Hydatina senta, Brachionus urceolaris, and species of Salpina, all died. Although they are easily destroyed by being frozen, some of them will bear a great variety of temperature. Thus the Phi-lodina roseola, which we have found in the streams of Yorkshire, has been discovered by Professor Agassiz amongst the red snow of the Alps, where it must have been exposed to a much lower temperature than in the former habitat. Polygastria bear also a higher degree of heat than Rotifera. Brachionus urceolaris and Hydatina senta were found alive after having been expbsed for thirty seconds to a\ntemperature of 104\u00b0 Fah. Higher temperatures speedily destroyed them.\nOne of the most remarkable points in the economy of the Rotifera is the power they possess of recovering their vitality after having been apparently perfectly desiccated. This fact was first made known by Leeuwenhoek, who, at the same time that he discovered the existence of the common Rotifer, had an opportunity of observing this remarkable property. In one of his original papers, contributed to the Royal Society of London, he says : \u2014\n\u201c In October, 1702, I caused the filth or dirt of the gutters, when there was no water there, and the dirt was quite dry, to be gathered together, and took about a teacupful of the same and put it into a paper upon my desk, since which time I have often taken a little thereof, and poured upon it boiled water, after it had stood till it was cold, to the end that I might obviate any objection that should be made, as if there were living creatures in that water. These animalcula, when the water runs off them or dries away, contract their bodies into a globular or oval figure. After the above-mentioned dry substance had lain near twenty-one months in the paper, I put into a glass tube, of an inch diameter, the remainder of what I had by me, and poured upon it boiled rain water after it was almost cold, and then immediately viewed the smallest parts of it, particularly that which subsided leisurely to the bottom, and observed a great many round particles, most of which were reddish, and they were certainly animalcula ; and some hours after I discovered a few that had opened or unfolded their bodies, swimming through the water ; and a great many others that had not unfolded themselves, were sunk to the bottom, some of which had holes in their bodies ; from whence I concluded that the little creature called the mite had been in the paper, and preyed upon the aforesaid animalcula.\n\u201c The next day I saw three particular animalcula swimming through the water, the smallest of which was 100 times smaller than the above said animalcula.\n\u201c Now, ought we not to be astonished to find that these small insects can lie twenty-one months dry, and yet live, and as soon as ever they are put into water fall a swimming, or fastening the hinder parts of their bodies to the glass, and then produce the wheels, just as if they had never wanted water. In the month of September I put a great many of the last-mentioned animals into a wide glass tube, which placed themselves on the sides of the glass presently, whereupon I poured the water out, and then observed that several animalcula, to the number of eighteen or nineteen, lay by one another in the space of a coarse sand, all which, when there remained no more water, closed up themselves in a globular figure.\n\u201c Some of the bodies of these animalcula were so strongly dried up, that one could see the wrinkles in them, and they were of a","page":398},{"file":"p0399.txt","language":"en","ocr_en":"ROTIFERA.\n399\nreddish colour ; a few others were so transparent, that if you held them up between your eye and the light, you might move your fingers behind them, and see the motion through their bodies.\n\u201c After that these animalcula had lain thus dried up a day or two, I invited some gentlemen to come and partake of the agreeable spectacle with me, that is, to see how the said animalcula would divest themselves of their globular figure, and swim about in the water. According to which, after my friends had satisfied their curiosity in viewing the animalcula in their oval or globular form, some of which were so pellucid as if they had been little glass balls, I poured some water into the glass tube, whereupon they presently sunk to the bottom, and then the gentlemen took the said tube into their hands, and viewing it one after another through a microscope, they saw the animalcula, after the space of about half an hour, beginning to open and extend their bodies, and getting clear of the glass to swim about the water, excepting only two of the largest of them, that stayed longer on the sides of the glass before they stretched out their bodies and swam away.\u201d\nSince the period that Leeuwenhoek made these observations, this subject has been one of great interest to naturalists ; and a question has been raised as to the condition of the dried animalcules. Leeuwenhoek seems first to have raised this question, by declaring that complete desiccation must involve the death of an animal, and as it could not come to life after once dead, that the revivified animalcules were not completely desiccated. The experiments of Leeuwenhoek were repeated by other observers, and the same results obtained. Needham not only saw it in the Rotifers, but also in the Vibrio of blighted wheat. His opinion was, that the desiccation was quite complete. Needham\u2019s experiments were repeated by Baker, who also came to the same conclusion. These observers were followed by Spallanzani, who, in a most elaborate series of investigations, confirmed the conclusions at which Needham and Baker had arrived. He, however, points out the fact, that the revivification of the animalcules was much more constant when they were dried with sand than when dried on a smooth surface. He found also that animalcules when in this desiccated state would bear a much greater heat, as well as a much more intense degree of cold, than when in an active state. Animalcules that, whilst living, would not bear a higher temperatare than 100\u00b0 Fahr., when dried were resuscitated after having been exposed to a temperature of 144\u00b0 Fahr. They also recovered after being exposed to a degree of cold 24\u00b0 cent, below zero. Although numerous facts of the same kind were recorded by subsequent observers, the accuracy of these observations have been doubted by several eminent naturalists, at the head of whom stands Bory St. Vincent, who, in the article Rotif\u00e8res, in the Dictionnaire Classique d\u2019Histoire Naturelle, says, that the desiccated animals have not been resuscitated\nat all, but that they are developed from eggs, in the same way as the Daphnia and other minute entomostracous Crustacea are developed after the first shower of rain which falls on the soil in which their ova are contained. The correctness of these observations can now hardly be doubted ; and since the time that Bory St. Vincent wrote, a great number of observers of undoubted accuracy, have repeated the experiments of Spallanzani and others, and have arrived at the same conclusions. Doy\u00e8re, a French naturalist, published a very extended series of investigations on this subject, in the Annales des Sciences Naturelles for 1842, in which various species of animalcules were perfectly desiccated and resuscitated under circumstances which would entirely prevent the supposition of a development such as was suggested by Bory St. Vincent. Experiments of the same kind have been performed by observers in our own country. Dr. Carpenter says, \u201c In the summer of 1835, I placed a drop of water containing a dozen specimens of the Rotifer vulgaris on a slip of glass, and allowed the water to dry up, which it did speedily, the weather being hot. On the next day I examined the glass under the microscope, and observed the remains of the animals coiled up into circles ; a form which they not unfre-quently assume when alive, but so perfectly dry that they would have splintered in pieces if touched with the point of a needle, as I had observed before in similar experiments. I covered them with another drop of water, and in a few minutes ten of them had revived, and these speedily began to execute all their regular movements with activity and energy. After they had remained alive for a few hours, I again allowed the water which covered them to dry up, and I reviewed it on the following day with the same result. This process I repeated six times ; on each occasion one or two of the animals did not recover, but two survived to the last, and with these I should have experimented again had I not accidentally lost them.\u201d\nProfessor Owen in his Lectures, after alluding to the experiments of Professor Schulze on this subject, says, \u201c I myself witnessed at Freiburg, in 1838, the revival of an Arctiscon, which had been preserved in dry sand by the professor upwards of four years.\u201d We must, however, quote one great authority against the view that a perfect desiccation of the resuscitated animals has ever taken place, and that is Professor Ehrenberg himself. He does not go so far as Bory St. Vincent, but regards the desiccation spoken of as an assumption, and supposes that the rotiferous and other animalcules which are revivified have the power of living in both water and air ; although they do not perform their functions so actively in the latter, yet that they still perform them. He says that he has seen the stomachs of Rotifera filled with granules of a conferva which was growing in the sand in which they were supposed to have been desiccated. Although we feel that the opinions of","page":399},{"file":"p0400.txt","language":"en","ocr_en":"400\nROTIFERA.\nEhrenberg on the subject of animalcules are entitled to great respect, we think that he has not investigated this subject with the candour that would entitle his conclusions to confidence. There is no a priori evidence why a perfect desiccation and suspension of the functions of life should not take place. This is the natural condition of the embryo of the seeds of many plants, which, after hundreds of years, when placed in proper circumstances, will exhibit all the functions of vegetable life. Amongst the highest forms of animals we often witness a suspension of the functions under special external circumstances, which, although not amounting to the extent found amongst the Infusoria, would yet prepare us to admit a far more intense degree of the same phenomenon amongst those beings in which animality was less decided, and the vegetative functions more predominant. There is no necessity to regard the condition of desiccation in which those animals may be placed as one of death. The conditions of the existence of the vitality of the animal, whatever they may be, are undoubtedly secured in this state, and the conditions of the activity of this vitality are alone withdrawn.\nAlthough many of the species of Polygas-tria are as large as the Rotifera, the structure of the latter is much more easily discernible, on account of the transparency of the lorica, or shield, in which they are enclosed, and the distinctness of their individual organs. The external covering, though always clear like crystal, has varying degrees of density, in\nsome instances forming a horny kind of case, insusceptible of movement, and, in others, a skin susceptible of transverse corrugations. Into this dense external membrane the animal is capable of drawing in its tail and rotatory organs; hence this class of animals has been called Systolides. In none of the species does there appear to be a deposit of earthy salts, either in the skin or other parts of the body.* This will account for the fact, that few or none of the Rotifera have been found in a fossilised state. Those forms alone of the Polygastria have been discovered in the chalk and subsequent formations, which, in their living state, possess a siliceous or calcareous skeleton.\nIn the classification of the Rotifera we shall follow Ehrenberg, as no separate arrangement of these creatures existed previous to his profound investigation of their structure ; and although other attempts have been made, since the appearance of his work, on the Infusoria, none of them seem better adapted for the purposes of further inquiry. At the same time we would, with the utmost diffidence, express our doubts as to the correctness of much of the terminology employed by Ehrenberg, implying, as it frequently does, views of the structure and functions of the parts of these animals which the facts themselves, so remarkably correctly observed, do not always seem to warrant. The following is a table of the eight families of Rotifera according to Ehrenberg : \u2014\nA single, continuous, ciliated wheel. (MONO-TROCHA.)\nMargins of J^els! Sldn soft, or naked.\n(\tI Skin hard or loricated.\nentire.\nCHA.)\nMargins of the wheels'] crenated.\nTROCHA.)\nNaked.\n(ScHIZO-j Loricajed. wheels.! Naked.\n.\t,\t.. ., . f Many-parted\twheels.! Naked.\nAc\u00fci\u00eftedwheeT TsO-\u2019 (Polytrocha.)\t} Loricated.\n1 Two-parted wheels. (Zy-1 Naked, t gotrocha.)\tj Loricated.\nciliated wheel. ROTROCHA.)\nIcthydina.\n\u0152cistina.\nMegalotrochcea.\nFloscularia.\nHydatin\u00e6a.\nEuchlanidota.\nPhilodin\u0153a.\nBrachioncea.\nIt will at once be seen that this is an exceedingly artificial arrangement ; for although the rotatory organs are the most striking external character of the Rotifera, the function they perform does not seem to be of that fundamental importance in the economy of the animal, so that a change in their form would be attended with corresponding changes in their general structure. In fact, in this arrangement, forms are separated which are nearly related by the affinities of more important organs. In the next place, the families are arranged according as they are naked (panzerlose), or loricated (gepanzerte). The condition of the integument here employed as a means of classification, cannot be regarded as absolute ; and there are species which it would be difficult to refer to either group. Some of the species secrete around them an external tube, in which they dwell, as Stephanoceros ( dg. 292.) and others, which is an entirely different thing from the hardened integument , called by Ehrenberg the lorica, or shield, and yet these are classed as a loricated family. It is, however, but due to Ehrenberg to state that\nhe is not unaware of the defects of this arrangement, and that he has pointed out that both the structure of the alimentary canal, and even the teeth and jaws, would afford characters by which the species might be arranged. Dujardin, in a recent work on the Infusoria, proposes the four following families : \u2014\n1.\tRotifers having the posterior part of their bodies fixed. Examples : Floscularia, Stephanoceros.\n2.\tRotifers having but one means of locomotion, that of the vibratile cilia, and which are consequently always swimmers. Examples : Plygina, Lacumolaria., Melicerta.\n3.\tRotifers which have two modes of locomotion : one creeping like the leech, the other swimming as the last. This family includes the largest number of genera, as Brachionus, Dinoch\u00e2ris, Pterodina, Salpina, Lepadella, Euchlanis, &c.\n* Ehrenberg states that the remains of some Rotifera having been chemically examined; they were found to contain phosphate of lime, which he supposes was deposited in their jaws and teeth.","page":400},{"file":"p0401.txt","language":"en","ocr_en":"rotifera.\n401\n4. Rotifers without vibratile cilia, but which are supplied with nails, by means of which they walk. Examples : Hydatina, Notom-mata, Furcularia, fyc.\nDujardin, in his work, also objects to the characters on which Ehrenberg has constituted the various genera belonging to his eight families, these genera being principally determined by the presence or absence of little red spots, which Ehrenberg designates as eyes. (Fig. 292. a ; fig. 303. a ; fig. 296. a ;fig. 294. a ; fig. 298. a ; fig. 299. b.)\nThe following is a description of the families adopted by Ehrenberg : \u2014\nFamily 1. \u2014 Icthydina. Character. Naked Rotifers, with a single continuous rotatory organ, not lobed at the margin.\nIn the genera Ptygura and Glenophora, the rotatory organ is circular, and serves as a means of locomotion. In Ch\u0153tonotus and Icthy-dium it is elongated, elliptical, band-like, and seated on the ventral surface. Ch\u0153tonotus and Icthydium possess a furcated foot, Ptygura and Glenophora a simple one. Icthydium and Ch\u0153tonotus have a simple conical intestine, with a long thin oesophagus without teeth (?) Glenophora, a short oesophagus with two teeth; Ptygura,a constricted stomach with three teeth (fig.288.). Pancreatic glands are only seen in Ch\u0153tonotus and Ptygura. C\u00e6cum, gall-ducts, and male sexual organs not observed. In two genera, the female sexual system consists of an ovarium with a few large ova. The evidence of the existence of a nervous system is seen in the two large red frontal eyes of Glenophora. Ch\u00e6tonotus has a hairy back.\nAnalysis of the genera : \u2014\nr\t[A single foot. Ptygura.\nFig. 288.\nEyes absent.\nNo hair.\nHairv.\nfurcated!\nfoot.\n'f Icthydium. Ch\u0153tonotus.\nTwo\neyes.\nPtygura melicerta. (After Ehrenberg.')\n1, partially expanded ; 2, completely expanded, the cilia in action causing currents indicated by the arrows ; 3, contracted.\na, a, a, contractile vesicle ; b, situation of the anal orifice.\nof teeth for chewing (fig. 289. a, a), two pancreatic glands. Ova and ovaria have been Fig. 289.\nGlenophora.\nThese genera embrace six species, some of which have been known to microscopic observers under various names, from a very early period. Icthydium podura was described by Joblot, as poisson \u00e0 la t\u00eate tr\u00e9fl\u00e9e, in 1718. The Ch\u0153tonotus larus was described by Muller in 1776 as Trichoda acarus.\nThis family embraces some of the simplest forms of the Rotifera. It may perhaps be doubted as to whether this class at all is the place for the genus Ch\u0153tonotus. They have no distinct rotatory organ, and their bodies covered with cilia, place them in very close alliance with some forms of the Polygastria, especially the Euplota, from which they are distinguished by their symmetry, and distinctly furcated tail. Dujardin places Ch\u0153tonotus amongst his symmetrical Infusoria, which do not include the Rotifera or Systolides.\nFamily 2. \u2014 CEcistina. Character. Ro-tiferous animals, with a single rotatory organ entire at the margin, enclosed in a shield.\nThe organs of motion consist of internal muscles and an entire foot or tail. The organs of nutrition are an apparatus with rows\nVOL. IV.\nConochilus volvox. (After Ehrenberg.) a, a, jaws and teeth ; b, b, papill\u00e6 ; c, c, c, c, glands ; d, d, ovarium.\nobserved in the two forms of which the family consists. Vessels, two filiform tremulous organs (called by Ehrenberg \u201cgills\u201d); nervous\nD D","page":401},{"file":"p0402.txt","language":"en","ocr_en":"ROTIFERA,\n402\nfibres, with ganglia, are seen in Conochilus, and two red eyes are seen in both genera. t\tf Confined to an in- 1\t. ,\nLoSd.or\tI \u0152cate\u2019-\n(_ Common to many. Conoclnlus.\nIn the less circular rotatory organ than in Ptygura we see the tendency in these animals to the more compound forms of that organ. The lorica, in this family, is not homologous with this organ in many of the other loricated species ; but a case formed by a secretion from the surface of the body of the animal, as is seen in some Annelides, and occasionally in the aquatic larvae of insects. The social habit of Conochilus is very remarkable in this group, as many as forty individuals being frequently found together, attached by their tails, and the consequence of the action of their rotatory organs is a circular movement of the whole mass {fig. 290.). This habit is not confined to Conochilus amongst the Roti-fera ; but it is interesting as connecting this class in habit with the compound Polygastria on the one side, and the Cirripedia and compound Ascidia on the other.\nFig. 290.\nThe animals of Conochilus volvox, half contracted, forming a circle. (After Ehrenberg.')\nFamily 3.\u2014Megalotroch\u0153a. Character. Monotrochous rotatory animals, with the margin of the rotatory organ incised or flexuous, not inclosed in a shield.\nThe flexuous extended rotatory organ is used for locomotion, swimming, and the supply of nutriment. Muscular bands are evident in the interior, by which the form of the body is changed. In Megalotrocha, the alimentary canal is supplied with a stomach, two caeca, jaws with a double row of teeth, and two pancreatic glands. In the other two species there is a single canal, without stomach or caeca. Microcodon has jaws with two teeth. Cyphonautes is toothless. The reproductive organs consist of an ovarium. The ova in Megalotrocha are attached to the parent by a thread. Vessels, and tremulous gill-like organs, are observed in Megalotrocha. The organs of the senses are in two genera \u2014 the red eyes. Megalotrocha exhibits radiated nervous masses, and above these four dark glandular bodies in the neighbourhood of the mouth. These have been erroneously regarded as eyes (fig. 291.).\nAnalysis of genera.\nEyeless.\tCyphonautes.\n_T.,,\tf One eye.\tMicrocodon.\nWith eyes.\t|Two eyes.\tMegalotrocha.\nOf these three genera, Megalotrocha is the only one that is well known, or that appears\nto answer to the description of the family. Cyphonautes is a marine animal, of which Ehrenberg has seen but two specimens. Microcodon has also doubtful characters. Megalotrocha, of which there is only one species, M. albo-fiavicans, has often been described by the older observers.\nFig. 291.\nMegalotrocha flavicans. (After Ehrenberg.)\na, a, nervous ganglia ; b, jaws; c, ovum ; d, d, bodies whose functions are unknown ; e, e, e, e, transverse vessels.\nFamily 4. \u2014 Floscularia. Character. Monotrochous loricated Rotifers, with a rotatory organ, with sinuous lobed or multifid margins.\nThe rotatory organ is divided more or less deeply into two, four, five, or six divisions. In the last case they may be almost said to be compound. The alimentary canal generally exhibits a stomach, and is supplied with jaws and teeth. Flosculiria has no stomach. Lacinularia has two caeca. Semilunate pancreatic glands are seen in all the species. A short ovarium, producing a few ova at a time,","page":402},{"file":"p0403.txt","language":"en","ocr_en":"ROTIFERA.\n403\nis found near the foot in all the genera. Male organs, as glands, exist in Ladnularia and Melicerta, perhaps also in Floscularia and Stephanoceros. Vessels are seen in Lacinu-laria. Tremulous gill-like organs in Stephanoceros and Ladnularia. Eyes are seen in all\nFig. 292.\nStephanoceros Eichornii. (After Ehrenberg.')\na, single eye ; b, b, nervous ganglia ; c, crop, containing a navicula and other infusory animalcules ; d, jaws ; e, anal orifice ; ff ova.\nexcept Tubicolaria. Nerve-like ganglia may be found in Ladnularia, Limnias, and Melicerta. Two pairs of muscles contract the body posteriorly (y%. 5.).\nEyes not! present. /\nAnalysis of the genera.\nTubicolaria.\nOne eye.\nTwo eyes (when young).\nStephanoceros'\nWheels 1 Separate. Limnias.\n2-parted. ) Segregate. Ladnularia.\nWheels 1 4-parted. j I Wheels 5-or] L 6-parted.j\nMelicerta.\nFloscularia.\nFig. 293.\nHydatina senta. (After Ehrenberg.) a, brain ; b, nervous cords ; c, ganglia ; d, alimentary canal, containing infusory animalcules; e, e, e, e, muscular fibres; f f f f, transverse vessels ; g, respiratory orifice ; h, seminal tubes ; t, anal orifice.\nD D 2","page":403},{"file":"p0404.txt","language":"en","ocr_en":"404*\nROTIFERA.\nAlthough, at first sight, this might appear a very natural group, a little examination of their so-called rotatory organs will, suggest the propriety of separating from the rest the genera Floscularia and Stephanoceros. The organs which are called rotatory in those genera are evidently, as Dujardin has pointed out, more like to the bristles or setae of the lorica of other species, than to the true rotatory organs. The cilia, as they are called, of Floscularia, do not move at all. The bristlelike organs of Stephanoceros are covered with cilia, which appear to be vibratile. The lo-ric\u00e6 of these animals also consist not of the integument rendered horny, but of a case secreted from the outside of the body of the animal. The animal has the power of retiring into this case, and in Stephanoceros this habit, combined with its structure, give to it a strong resemblance to some of the Cilio-brachiate Bryozoa. This external resemblance is so great, that many of the earlier observers referred it to the Polypifera. Oken referred it to the hydroid polyps, and placed it between Hydra and Tubularia. Goldfuss referred it to a position in the same class between Coryna and Cristatella.\nIn the genus Lacinularia, the same tendency to association exists, as is found in Conochilus.\nThe genera Floscularia and Stephanoceros constitute the first family of Dujardin. The remaining genera, previously noticed in this and the other families, are referred to his second family.\nFamily 5.\u2014Hydatin\u00e6a. Character, Naked Rotifers, with a many-parted rotatory organ.\nAll the species of this family agree in the divided condition of their wheels, which do not consist of a circular or semi-circular row of cilia, but of several distinct rows or circles of such cilia, which are distinctly separated\nfrom each other. All the three forms, except Polyarthra, have an elongated pincer-like process, proceeding from the abdomen, which resembles a tail, but is no proper continuation of the dorsal integument. In many species, a muscular apparatus is visible, by which the form of the body is changed. The nutritive organs in all cases are very obvious. It is mostly a simple conical intestine, which, in the great proportion of species, is without the constriction, which forms a kind of stomach (fig. 293. d). Triarthra longiseta (fig. 297.) is, however, an exception, and exhibits a stomach formed by the constriction of the alimentary canal ; whilst Notommata myrmeleo (fig. 303. c) with some other species have a kind of gastric enlargement, terminated by a narrow anal orifice. The commencement of the alimentary canal, with one or two exceptions, in all the genera, is supplied with jaws and teeth. Pancreatic glands are constantly present. The reproductive system is hermaphrodite. The ovarium (fig. 303. i) is elongated ; the eggs few. The male organs consist of two filiform elongated glands (fig. 303. g), and two contractile vesicles. The ova appear under two forms, one smooth and soft, the other hard and spinous. Notommata brachionus, and the genera Polyarthra and Triarthra, bear their ova, like the Crustacea, attached to their sides. In several of the genera a vascular system has been observed (fig. 293./,///), in the form of transverse and longitudinal vessels, the latter supplied with the tremulous organs called gills ( fig. 303./, /). With this system, a kind of tap, or simple opening, in the neck (fig. 293. g) is connected. In fifteen of the genera, the two eyes, with their accompanying nervous ganglia ( fig. 293. c), indicate the existence of a sensationary system. In Hydatina and other genera, nervous ganglia are seen in other parts of the body.\nEyeless.\nWith eyes.\nOne eye.\nTwo eyes.\nThree eyes.\nNo teeth.\n'Eye frontal.\nEye in neck.\nEyes frontal.\nEyes in neck.\nEyes sessile.\nTwo frontal pedi-culated, one in neck sessile. Eyes more fin single heaps, than three. \\In two heaps.\nAnalysis of the genera.\nFoot styliform.\nFoot furcated, cilia frontal,\nNo foot, dividedl fins.\t/\nf A furcate foot.\nI Styliform foot.\t{K^ded.\nFoot furcate.\nIn neck.\nTwo frontal, one] in neck.\tj\nEnteroplea.\nHydatina.\nPleurotrocha.\nFurcularia.\nMonocerca.\nSynch\u0153ta.\nScaridium.\nNotommata.\nPolyarthra.\nHiglena.\nTriarthra.\nRattulus.\nDistemma.\nTriophthalmus.\nEosphora.\nOtoglena.\nCycloglena.\nTheorus.\nThis family contains a larger number of very generally diffused ; and Ehrenberg, in his species than any of the others. They are microscopic labours, in many parts of the","page":404},{"file":"p0405.txt","language":"en","ocr_en":"R0T1FERA.\t405\nworld, observed them in the north of Africa and the north of Asia ; they are commonly distributed throughout Europe. The localities they inhabit are very various, some are found in fresh water, other in salt. They are fond of conferv\u00e6, and may be easily found nestling among these plants. They sometimes are in great numbers, so that they discolour the waters in which they exist. The species of Triarthra give a milky opaqueness to the water in which they are found. The species of Polyarthra are interesting on account of the finlike organs which are developed at their sides, and by which they are able to move about. Several of the Notom-mata are parasitic on other animals, and thus approach in habit some of the higher epizoa. The elongated setae or bristles of the species of Triarthra are also worthy of notice (fig. 297.).\nFamily 6. \u2014 Euchlanidota. Character. Loricated Rotifers, with a many-parted rotatory organ.\nAll the species of this family are clothed with a lorica, which resembles the exoskeleton of tortoises or crabs. Many of the species\nare remarkable for the appendages of the shield, as set\u00e6 in Euchlanis and Stephanops, hooks (uncini) in Colurus, horns (cornicula) in Dinocharis, spurs or respiratory tubes (calcar sipho) in Euchlanis (fig. 294.) and Salpina, a helmet (cucullus), in Stephanops. Most of the species have a furcated foot, some few of them have styliform feet. The interior of these animals is not so well observed as in families where the shield is of a less dense character. A muscular system, consisting of both longitudinal and transverse fibres, and muscles to move the foot, can be seen in most species. The nutritive organs consist of a muscular oesophageal head, furnished with two jaws bearing teeth. The oesophagus is mostly a short tube. In eight genera the alimentary canal assumes a conical form, in the remainder it is constricted into a gastric organ. Two round or egg-shaped intestinal glands are present in all the species. The anal orifice is situated at the back of the basis of the foot (fig. 302. a). An ovarium with small ova, in four genera, Euchlanis, Monostyla, Stephanops, and Squamella, are seen, in the form of\nFig. 294.\nEuchlanis triquetra. a, single eye ; b, band of muscles with transverse stri\u00e6 ;\novarium ; d, alimentary canal.\nD D 3","page":405},{"file":"p0406.txt","language":"en","ocr_en":"406\nROTIFERA.\ntwo strap-shaped sexual glands and contrac- tionary system is indicated [by the presence of tile vesicles. Traces of a vascular system are eyes, which are visible in ten genera and thirty-seen only in a few species. The sensa- three species.\nAnalysis of the genera.\nEyes\nsent.\nEyes\nsent.\n1 J\tFoot furcate.\n\tStyliform foot. j\nOne eye in. neck.\tFurcated foot.\n\t\u25a0 Styliform foot.\nTwo eyes frontal.\tFurcated foot.\nFour eyes.\tFurcated foot.\n\tLepadella.\nDepressed shield.\tMonostyla.\nPrismatic shield.\tMastigocerca.\nShield gaping be-\") neath.\tEuchlanis.\nShield closed be.fShield horned-\tSalpina.\nneath.\t1 Shield\twithout 1 horns.\t| Dinocharis.\n\tMonura.\nShield somewhat I\t\ncompressed or > prismatic.\tJ\tColurus.\nShield depressed/Hooded, or cylindrical. /Not hooded.\tStephanops. Metopidia.\n\tSquamella.\nIn this as in the preceding family, there can be little doubt that the artificial character, the number and position of the so-called eyes, on which the genera are founded, separates species which are united by much more important characters. Thus Dujardin remarks, that the genera Lepadella, Metopidia, Ste-phanops, and Squamella are separated only by characters which vary according to the nutrition of the animal and the time of the year. The same remark will apply to many of the genera of the preceding family Hyda-tinaea. The species of this family are found in both salt and fresh waters, and have a wide distribution over the surface of the earth. The genus Lepadella is developed sometimes in stagnant water in such quantities as to give it a milky appearance.\nFamily 7. \u2014 Philopin\u00e6a. Character. Naked Rotifers with two rotatory organs.\nThe body of these animals is mostly of a ten-uiform, cylindrical, or spindle-shape, with false articulations, by which, through its muscles, the animal is enabled to withdraw the parts of its body one within another, like the tube of a telescope. The double rotatory organ, so evident in Rotifers (fig. 301.), is seen in all the species. In every species there is a furcated foot. In the genera Callidina, Rotifer, Actinurus, and Philodina, appendicular hooks are found on the false articulations (fig. 295.), A muscular system is seen in Callidina, Actinurus, Rotifer, and Philodina. Three of the genera have two jaws with two teeth, and two jaws with a row of teeth. A filiform intestine, with a vesicular enlargement at the end, is seen in four of the principal genera. Intestinal glands are seen in four genera. The reproductive system is hermaphrodite in lour genera, with an ovarium and male sexual glands, and contractile vesicles, The last are only seen in Rotifer and Philodina. These two genera and Actinurus sometimes produce living young. Traces of a vascular system in the transverse vessels of Rotifer and Philodina, and also in the respiratory tube or opening\nof these genera, and of Actinurus and Mono-labis, are seen. Nervous masses are found under the eyes.\nFig. 295.\nPhilodina roseola. (After Ehrenberg.)\na, respiratory tube ; b, alimentary canal ; c, cellular mass; d, terminal intestinal pouch; e, anal orifice.","page":406},{"file":"p0407.txt","language":"en","ocr_en":"ROTIFERA.\n407\nAnalysis of the genera.\nEyes absent.\nEyes present.\nWith proboscis,'and appendicular processes on foot.\nNo proboscis or processes.\n\u2022Wheels pedunculated. [Wheels sessile.\nTwo frontal eyes.\n(Foot with processes. Foot without processes.\n/Two toes. [Three toes. Two toes.\n.Two cervical eyes.\nCallidina.\nHydrias.\nTyphlina.\nRotifer.\nActinurus.\nMonolabis.\nPhilodina.\nThis family, which includes the true Rotifers of Dujardin, embraces some of the least known, as also the most common, animals of the class. The genera Hydrias and Typhlina were found during the travels of Ehrenberg in Asia. Callidina and Monolabis have been found by Ehrenberg at Berlin only. The Rotifer vulgaris was the first wheel-animalcule ever seen, and is certainly the most common of the whole class. It was described with great accuracy by Leeuwenhoek in in his early papers on its discovery. It is this animal which has also been most frequently the subject of the desiccating experiments to which we have alluded. Actinurus Neptunius was known to the earlier observers of these creatures as the wheel-animalcule with the long foot, on account of the extension of its foot or tail. The Philodina, though not an unfrequent genus, was first described by Ehrenberg in 1838. The articulated character of the integument in the species of this family, give them a habit different from the rest of the group : by means of their probiscoid mouth and prehensile tail, they can successively grasp the object on which they are placed, and are thus enabled to crawl in the same way as the leech and other Annulosa. The affinity between the Rotiferae proper and the Arctiscon and whole family of Tardigrades, which are not admitted as Infusoria by Ehrenberg, has been pointed out by Doyere ; and there can be little doubt that we have, through this group, a transition from the Rotifer\u00e6 to the Annelida.\nThe Rotifer vulgaris is found very commonly in the ponds and ditches of England, where it attaches itself to the Confervae, the various species of Lemna, and the Cerato-phyllum, which are so abundant in these places. M. Morren, of Liege, has recently pointed out a curious habitat for this animal. Rceper, many years ago, observed that this animalcule sometimes penetrated the cells of Sphagnum, and even lived in those parts of the plant which were not immersed in water. Unger described, in 1828, some vesicles in the structure of Vaucheria clavata, which had the power of moving about spontaneously, and which he discovered were produced by an animalcule in their interior. The subsequent researches of Morren showed that this animalcule was truly the Rotifer vulgaris. It seems to prefer such a situation to its liberty, for Morren says, \u201c One day 1 opened a protuberance gently ; I waited to see the Rotifer spring out and enjoy the liberty so dear to all creatures, even to imprisoned animals ; but\nno, he preferred to bury himself in his prison, descending into the tubes of the plant, and to nestle himself in the middle of a mass of green matter, rather than swim about freely in the neighbourhood of his dwelling.\u201d\nThe species of Philodina are beautiful animalcules. P. roseola has a rose colour of its whole body ; and the ova, when deposited, have a reddish colour. The ova of this animalcule are deposited in little heaps, which the parent attends to, and even remains with the young ones after they are hatched, which Ehrenberg attributes to a kind of social instinct. Professor Agassiz found this creature amongst the animalcules which contribute to the colour of the red snow. It was at one time supposed that this colour was due to a species of Alga, the Protococcus nivalis, Mr, Shuttleworth, of Berne, was the first to announce that he had found, in addition to the cells of a plant, several species of Polygaslria, belonging probably to the genus Astasia. Subsequently to this announcement, Professor Agassiz discovered the presence of this animalcule in the same situation. The author of this article has found Philodina roseola in company with a red animalcule, apparently a species of Astasia, in waters slightly impregnated with sulphuretted hydrogen. Ehrenberg says this animal sometimes occurs entirely colourless, so that its colour may depend on its food.\nFamily 8. \u2014 Brach ion\u00e6a. Character, Loricated Rotifers, with a double rotatory organ.\nThe external covering of these animals is a testula, such as is possessed by the tortoises, not a scutellum, as found in the Crustacea. The motory system consists partly of external organs, and partly of internal muscles. The rotatory apparatus is often apparently composed of five parts\u2014three in the middle and one on each side. The latter only can be regarded as the true rotatory organs ; the middle portions are only ciliated frontal processes. In the genus Synch\u0153ta there are two setae in the rotatory organs, which are also possessed by the Brachion\u00e6a. Noteus and Rrachionus have a furcate foot, Anur\u0153a is footless, and Pterodina has a kind of sucker in its place. The nutritive organs are very similar to those of the Hydatinaea and Euchlanidota. Intestinal glands have been observed in all the species. The reproductive organs consist of an ovarium, with a few large eggs, which are not hatched internally, but, with the exception of Pterodina, are externally attached to the parent after expulsion. The male organs consist of glands and contractile vesii\nV D 4","page":407},{"file":"p0408.txt","language":"en","ocr_en":"408\nROTIFERA.\ndes. The vascular system is composed of tremulous gill-like organs, and a respiratory spur or tube in some species. Noteus has no eyes, but a large cerebral ganglion ; the other genera have eyes.\nAnalysis of the genera.\nEyeless, with furcate foot.\tNoteus.\nOne\tini Without foot.\tAnur\u0153a.\nWith neck.\tJ Foot furcated.\tBrachionus.\n^eyeg^^jstybform foot. Pterodina.\nWith the exception of Noteiis, the genera of this family were known to the older observers. Three species of Anur\u00e6a were described by M\u00fcller in 1776, and Joblot discovered the Brachionus pala {fig. 296.) in 1716.\nlarge quantities that they render the water turbid in which they exist.\nDoyere has constructed a family which he calls Tardigrades, and which are most properly included in the class of Rotifera. The animals of this family have an elongated body, contractile like that of the Rotifer, with four pairs of short legs, each bearing two pairs of small claws. The alimentary canal is narrow, prolonged into a siphon at its anterior extremity, with an internal maxillary apparatus, moveable, and consisting of a muscular bulb traversed by a straight canal, furnished with horny articulated pieces. Until this family was investigated by Doyere, it was supposed to consist of but one species, the Water-bear ( Wasser-b\u00e4r) of Eichorn ; but under the name\nFig. 296.\nBrachionus pala. (After Ehrenberg.')\na, eye ; b, jaws ; c, ovary ; d, d, ova ; e, contractile vesicle ; f, ova attached ; g, g, g, teeth of shell ; h, intestinal glands ; i, constriction of alimentary canal ; k, respiratory tube ; l, l, transverse vessels.\nA,\nThe Pterodina patina was described by Eichorn in 1775. The genus Brachionus is, of all the Rotifers, the most remarkable for the density of its lorica. The thickness of this organ prevents their internal structure from being so plainly obseived as that of many other genera. The species of Brachionus olten occur in so\nof Macrobiotus, Arctiscon, and other names, which were supposed to be synonymous, it appears that several animals were confounded, for which Doyere proposes the generic terms Emydia, Milnesia, and Macrobiotus. These animals are found in the same localities as the common Rotifer, and like it possess the","page":408},{"file":"p0409.txt","language":"en","ocr_en":"R0T1FERA.\t409\nsame faculty of resuscitation after desiccation. On account of the slow movement of Macro-biotus, they have been called Tardigrada ; an objectionable term, because applied to a family higher up in the scale of development. On account of their habit of crawling, and not swimming as the great mass of Rotifers, Dujardin names them Systolides marcheurs. They are interesting as connecting the Rotifers, not only with the Annelida, but also, through their four pair of feet, with the higher forms of the Articulata, and on the other side with the Helminthida. Ehrenberg regards Macro-biotus not as a Rotifer, but as an animal related to Lern\u0153a. This epizoon and its congeners have undoubtedly more affinity with the articulate than with the molluscous tribes ; and the relation of the Tardigrades with the Rotifers establishes for that family a more decided tendency towards the articulate groups than any other.\nAlthough the organisation of the Rotifera is included in too small a space to permit of dissection, the transparency of their integuments is so great as to permit of an easy ex-*, amination of their internal organs. From the previous descriptions of the families of this order, it will be seen that their organisation is very complicated, and that their size is by no means the measure of their position in the animal scale.\nTegumentary system.\u2014 The Rotifers are all covered with a resisting tegument, more or less flexible, and which is the last part of the body to decompose. The composition of this tunic, although possessing various degrees of density, appears to be entirely organic ; and the absence of siliceous or calcareous matter will account for these animals being never seen in a fossilised state. The investing membrane is open in front, to allow of the contact of the fleshy interior with the water in which the creatures live. There is, also, an anal orifice. In those species in which this membrane is not hardened, so as to form a shield, it is capable of being folded by the action of the muscles, and possesses a number of false articulations. The anterior part, to which are attached the vibratile cili\u00e6 constituting the rotatory organ, is capable of being retracted into, or thrust out from, the rest of the body. All the parts of the body retract within the skin into a kind of globule, when the animal is removed from the water. The tegument has attached to it various organs, as the claws in Emydium, the cirrhi, or fins, of Polyarthra, and the elongated setae of Tri-arthra {fig. 297.), the teeth in the dense tegument, or lorica, of Brachion\u0153a (fig. 296. g, g). The tail, or foot, must be regarded as an elongation of the tegument. It varies much in size and length. Sometimes it consists of a single styliform seta, as in Tnarihra longi-seta (fig. 297.) ; in the genera Monura and Monostyla it is styliform, but is also articulated. In some of the species of the genus Anur\u00e6a there is no tail at all. In most instances the tail is forked, as in Hydatina, Euchlanis, Philodina, Rotifer, Brachionus, Sfc.\n(figs. 293\u2014296.). Sometimes the tail is divided from the point of its origin with the tegu-\nFig. 297.\nTriarthra longiseta. (After Ehrenberg').\na, a, muscular fibres ; b, contractile vesicle ; c, c, intestinal glands.\nment of the body, as in Notommata longiseta (fig. 298.) and in Hydatina senta (fig.293.). More frequently a portion intervenes between the body and the terminal processes. This is soft and movable in every part in Brachio-nus pala (fig. 296.) ; forms a series of sheaths","page":409},{"file":"p0410.txt","language":"en","ocr_en":"410\tROTIFERA.\nin others, as Dinocharis paupera (fig. 302.), and many of the Philodin\u00e6a. The tail is\nFig. 298.\nNotommata longiseta. a, single eye ; b, anal orifice.\noften furnished with supplementary setae, or bristles, and in Pterodina it is terminated with a row of vibratile cilia. The tail is used as a rudder, an oar, and a hold-fast. When styli-form, it seems used as a rudder, although in some cases apparently employed to propel the animal. When furcated it has the power of\nopening and closing the processes on each side, and apparently holding on to any object by their means. Many genera, as Conochilus, Floscularia, Stephanoceros, and others, have no fork, but remain fixed by their tails. Even in species which have forked tails, as in the Philodin\u00e6a, the creatures seem to have the power of fixing themselves independently of their fork. It would thus seem not improbable that the tail in these cases acts as a kind of sucker.\nFig. 299.\nRotifer vulgaris. (After Ehrenberg.) a, orifice of proboscis ; b, eyes ; c, probiscoid process; d, spur or respiratory tube; e, jaws;/, alimentary canal; g, g, g, g, transverse vessels; h, muscular fibres ; i, t, seminal canals ; k, young animal.","page":410},{"file":"p0411.txt","language":"en","ocr_en":"ROTIFERA.\n411\nProjecting from the upper part of the external tegument, in many species, is a little process, which Ehrenberg calls a spur, or siphon {fig. 299. d), and which he thinks is connected with the function of respiration, and therefore calls it a respiratory tube. It corresponds with an orifice in some species (fig. 293.g), which Ehrenberg calls the respiratory orifice. He has also hinted that they may be connected with the reproductive function. Two of these organs are seen in some of the Notommata and other genera, and they are sometimes covered with cilia. Dujardin thinks that they resemble more closely the i and antennae of the Entomostraca. he rotatory organs, or wheels, must be also regarded as a portion of the tegumentary system. They are fleshy retractile lobes, covered with vibratile cilia, capable of being contracted or expanded at the will of the animal. The movement of the cilia when the lobes are expanded gives the appearance of a wheel moving upon its axis, an appearance which was a source of much wonder to the earlier observers of these creatures. In addition to the vibratile cilia, there are frequently found, on the rotatory lobes, setae, or bristles, which have not the power of moving. This is the case in Floscularia, if, indeed, the organs called rotatory in that genus are truly homologous with the rotatory organs in other species. The true homologue of the rotatory apparatus in Floscularia appears to us to be seated within the external ciliated lobes, where an evidently active motion is constantly going on. The form of the lorica varies greatly ; in some species it is flat and depressed, as in Pterodina and Monostyla ; in others it is prismatic, as in Mastigocerca, or gaping, as in Euchlanis (fig. 294.). Some species, as Ste-phanoceros (fig. 292.), Floscularia, Melicerta, and others, have a soft skin, very contractile, which secretes externally a case, and which Ehrenberg calls a lorica; but this is essentially a different organ from the lorica. Where this case occurs, it seems to stand in the same relation to the animal as the Polypidon of the zoophytes. The animals which form these cases are also fixed, and retract their bodies within their case in the same manner as the Polypiferae. The Floscularia may be compared to the Hydroid Polyps, while Ste-phanoceros, with its ciliated tentacula-like processes, would appear to have a relation with the Ascidoid polyps.\nMotory system. \u2014 As the movements of the Rotifers are rapid and various, so we find their muscular system complicated. The principal organs of locomotion are the rotatory organs, by which alone the great mass of the Rotifers appear to move. The movements effected by these organs are performed principally by the agency of the vibratile cilia. Although no tissue has yet been discovered in the cilia of the Rotifera and Poly-gastria, Professor E. Forbes has observed fibrous tissue in the cilia of a species of Medusae, and there can be little doubt that the movements of the cilia, like those of organs to\nwhich muscles are attached, are of two kinds, one of which is under the control of the will, and the other not. In the Rotifera, the vibratile cilia of the rotatory organ appear to be under the control of the will of the animal. The extension and contraction of the rotatory apparatus is under the influence of longitudinal muscular bands, which are very evident in most of the species (fig. 293. e,e,e,e ;fig. 296.; fig. 294. b). Not only is it evident, from the action of these muscles, that they are under the control of the will of the animal, but Ehrenberg has described some of these muscles as possessing the striated character of the voluntary muscles of animals higher in the scale of organisation. Euchlanis triquetra (fig. 294. b) and the species of Eosphora are those in which striated muscles have been observed. This fact is interesting in connection with Mr. Busk\u2019s observation of the existence of muscular striae in Anguinaria spathulata, a form of ciliobrachiate polyps. It affords a proof not only of the relation of these two families, but also of both, to the articulate tribes rather than to the Mollusca. Mr. Busk, after the most patient research, has not been able to discover the presence of striae in the muscular system of the Mollusca. Not only have the longitudinal bands been regarded as active agents in the movement of the rotatory organ, but also certain transverse bands. These bands (fig. 293. fififif; fig. 299. g, g, g) have been described by Ehrenberg as transverse vessels. There seems to be little proof that such is their office.\nIn many of the Rotifers, more especially the Philodinaea, the tail is employed for the purposes of progression. In order to effect this, it is supplied with distinct muscular bands (fig. 293. e). Muscular fibres have also been described by Ehrenberg surrounding the oesophagus, and apparently assisting the jaws in their movements, in Conochilus (fig. 289.), P/eurotrocha, and other species.\nDigestive system. \u2014 This apparatus is perhaps more highly developed than any other part of the Rotifera. An oral and an anal orifice indicate the commencement and end of this system. It is furnished with jaws and teeth, an oesophagus, sometimes a distinct stomach, and various forms of intestinal glands. At the commencement of this system, we find a distinct masticatory apparatus, which consists generally of two semicircular pieces, to each of which is attached one or more\nFig. 300.\nJaws of Brachionus brevissimus. (After Ehrenberg.)\nteeth, which act upon a central plate (fig- 300. ; fig. 299. e;fig. 289. a, a) fig. 296. b ;fig. 292. d ;","page":411},{"file":"p0412.txt","language":"en","ocr_en":"412\nROTIFERA.\nfig. 291. b). To the semicircular pieces are attached some of the longitudinal muscles, which, by their action, cause the teeth to work upon the central plate. The general structure of the jaws is, in all instances, the same, but the number of processes, called teeth, varies considerably. Sometimes no such processes are discoverable, as in Cyphonautes; in others, there is but one tooth on each side, as in species of Synchceta, Diglena, Lepadella, and Mo-nostyla. Some have two on each side, as Mo-nocerca, Mastigocerca, and Rotifer (fig. 301.). Others, again, present three, four, or several teeth on each side, as in Brachionus brevissi-mus (fig. 300.), Triarthra longiseta (fig. 297.), Brachionus pala (fig. 296.). Such are the characters afforded by the teeth in this family, that Ehrenberg gives an arrangement of the\nearlier observers for the action of a heart. Although, in most instances, the food is brought to the jaws of the animal by the rotatory apparatus, yet we have often observed, in species of Brachionus, that they have the power of projecting their jaws beyond the margin of the tegumentary membrane, and bringing them immediately in contact with the substances on which they are feeding.\nThe form of the alimentary canal varies : it is sometimes a simple tube, as in Dinocharis paupera (fig. 302. b). In many species, an enlargement of the middle portion takes place from constriction of the canal, above and below, forming a kind of stomach, as in No-tommata myrmeleo (fig. 303. c), Brachionus pala (fig. 296.). Sometimes there are two en-\nFig. 301. 1\nRotatory organs of Rotifer vulgaris enlarged.\n(After Ehrenberg.)\na, hornlike process (respiratory tube) ; b, b, muscles of the jaws ; c, c, intestinal glands.\ngenera into orders, according to the absence or presence and number of the teeth, as follows :\u2014\n1.\tAgomphia. Rotifers without teeth. Examples : Chcetonotus, Enteroplea.\n2.\tMonogomphia. With a single tooth. Examples : Pleurotrocka, Furcularia.\n3.\tPolygomphia. With many teeth. Examples : Hydatina, Stephanoceros, Brachionus.\n4.\tZygogomphia. With double teeth. Examples : Rotifer, Philodin\u00e6.\n5.\tLochogomphia. With teeth in rows. Examples : Ptygura, Megalotrocha.\nThe teeth seem to form the most dense part of the body of the Rotifera, and, after the crushing of the animalcule, may be obtained for separate examination under the microscope.\nThe whole masticatory apparatus is attached to the upper part of the alimentary canal, the oesophageal head, where it may be observed, being constantly in motion. This movement, which goes on whether the animal is partaking food or not, was mistaken by the\nFig. 302.\nDinocharis paupera.\nBack view.\na, anal orifice -, b, alimentary canal.\nlargements of the canal, as in Tnarthra longiseta (fig. 297.). When the enlargement takes place below alone, as in Rotifer vulgaris (fig. 299.), and Philodina roseola (fig. 295. d), Ehrenberg calls this portion a rectum. Ehrenberg points out the form of the alimentary canal as a mode of dividing the Rotifera, as follow : \u2014\n1.\tTrachelogastrica, those with a long simple alimentary canal.\n2.\tC\u0153logastrica, with a short oesophagus and an oblong conical alimentary canal, as in Hydatina.\n3.\tGasterodela, in which the alimentary","page":412},{"file":"p0413.txt","language":"en","ocr_en":"R0T1FERA.\t413\ncanal is constructed into a bag or stomach, as\nBrachionus.\n4. Trachelocystica, with a simple alimentary canal, enlarged at the lower part, as in Rotifer.\nThe upper part of the alimentary canal below the jaws is called by Ehrenberg the oesophagus, and is said to be either long or short, according to the distance which intervenes between the jaws and the further enlargement of the alimentary canal. In some cases, as in Stephanoceros (jig. 292. c), there is an enlargement anterior to the origin of the jaws, which is called the crop or gizzard. Into this cavity the food is taken before it passes into the lower portions of the alimentary canal. The same organ is seen in Floscularia. In this animal it is evidently clothed with yibratile cilia, whose movements seem to make up for the deficiency of a true rotatory apparatus. The whole of the alimentary canal seems to be lined with vibratile cilia, for although they are too minute, in most instances, to be seen, yet the movement of objects in the interior of the canal, as well as the force and direction with which substances are occasionally propelled from the oral orifice, would lead to this conclusion. The whole of the alimentary canal is often inclosed in a mass of cellular substance, as seen in Philodina roseola (fig. 295. c), and Dinocharis paupera (fig. 302.).\nFig. 303.\nNotommata myrmeleo.\na, the single eye ; b, oesophagus ; c, alimentary canal ; d, d, muscular fibres ; e, e, glands ; f f, respiratory processes; g, sexual tubes (male?); n, germinal vesicle in ovum ; i, ovarium ; k, vascular network.\nAttached to the intestinal tube, and apparently enlargements of its walls, are various appendages, about whose functions there is much difference of opinion. The most constant of these bodies are seated on each side of the termination of the oesophagus. They are mostly two in number, one on each side (fig. 297. c, c ; fig. 289. c,c ; fig. 296. h, h.) Sometimes they are four in number, as in No-tommata myrmeleo (fig. 303. e, e), and in other cases more numerous. Ehrenberg originally regarded these as spermatic glands, but, subsequently, he called them pancreatic glands. Grant and others have called them indifferently pancreatic or salivary glands ; and if they are secreting organs at all, they probably perform the functions of these glands in higher animals. Seated lower down the alimentary canal than these, are sometimes seen other projections, having the appearance of follicles, and these have been supposed to secrete bile. Dr. Grant describes what we have called a cellular mass in Philodina roseola, as a number of \u201c short, straight biliary follicles,\u201d such as are seen in many of the higher forms of Annelides. Professor Rymer Jones regards the superior as well as the lower of these appendages, as the \u201c first rudiments of a liver.\u201d Dujardin is inclined to regard these appendages rather as caeca than glands.\nVascular and respiratory systems. \u2014 Although Ehrenberg has pointed out several structures in the Rotifera as indications of a vascular system, it is very questionable whether any circulation takes place through vessels at all. In Hydatina senta (fig. 293.), Notommata myrmeleo (fig. 303.), Rotifer vulgaris (fig. 299.), and many others, can be seen a series of transverse bands, lying directly under the tegument ; in Hydatina senta, these are connected with a longitudinal band, and these are regarded as a dorsal vessel and its branches. Doyere, with much propriety, regards these as a musculo-cutaneous system, analogous to a system of the same kind which he has described in the tardigrade Infusoria. In Hydatina senta, Notommata myrmeleo, and some other species, there are some free longitudinal cords, connected with a fine vascular network near the mouth, and which send filiform prolongations to the alimentary canal, which Professor Owen thinks may, with more probability, be regarded as \u201c sanguiferous organs.\u201d We must, however, express our doubts as to the existence of a vascular system in these animals at all. In some of the Rotifera, internal tubes are seen, called by Ehrenberg seminal tubes, and upon these are often placed a row of little projecting tremulous processes, on which he has bestowed the name of gills. These processes are not very numerous in Hydatina senta (fig. 293.) ; but they are more numerous in Notommata myrmeleo (fig. 303./, /). The tubes on which these gills are placed, communicate in some instances with vessels at the back part of the neck, which are again in relation with the siphon to which we have before alluded, and the whole is supposed to","page":413},{"file":"p0414.txt","language":"en","ocr_en":"*14\tROTIFERA.\nconstitute the rudiments of a respiratory system. Whatever may be the true function of these parts, it cannot be supposed that the oxygenation of the nutritive fluid, takes place entirely in these organs. Not only is the alimentary canal supplied with vibratile cilia, but its peritoneal surface, and the cavity in which it is placed, so that on these surfaces the respiratory changes might take place quite independent of these organs. Dujardin refers the office of certain contractile vesicles (fig. 297. b ; fig. 288. a.), regarded by Ehrenberg as connected with reproduction, to the respiratory function.\nNervous system and organs of the senses. \u2014 The undoubted existence of a muscular system, and in some cases exhibiting undoubted indications of the stri\u00e6 seen in the voluntary muscles of the higher animals, would prepare us for the existence of a nervous system in the Rotifera. Such a system has been pointed out by Ehrenberg, and indicated in several species by ganglia and nervous cords. In Hydatina senta ( fig. 293.) there is a large mass occupying the place of the supra-oeso-phageal ganglia in other families, and to which Ehrenberg has given the name brain. From this mass there proceed several cords, which are presumed to be nervous. There are also other ganglia in various parts of the same animal (fig. 293. c). In the expanded rotatory organ of the Megalotrocha fiavicans, we also see nervous ganglia, from which cords diverge in several directions (fig. 291. a, a). Masses of the same kind are visible in the Ste-phanoceros Eichornii (fig. 292. b,b).\nA more complicated arrangement of ganglia and nerves has been described by Ehrenberg in Notommata clavulata. Whilst some naturalists have admitted the correctness of Ehrenberg\u2019s conclusions with regard to these organs, others have thrown doubts on his observations altogether. It is not improbable that, with regard to some of the parts he has figured as nervous cords, that they may be more correctly referred to other systems. But, a prion, it was not improbable that a nervous system should exist in these animals ; and it is more probable that the organs in some parts, called nerves by Ehrenberg, should be so, than that they should be anything else. Under these circumstances, we are disposed to regard the conclusion, that these knots and cords perform the functions of nerves, as the most philosophical. An objection has been urged, against regarding the white masses as nervous ganglia, that ganglia are only seen under certain circumstances, such as the association of nerves, the concentration of nervous energy, or acting as centres of perception. Ehrenberg has pointed out the frequent co-existence of what he calls ganglia with the red spots, which he regards as eyes. These spots, which are seen also in the Poly-gastria, are very common in the Rotifera. Sometimes there is but one, at other times two, and not unfrequently three or more. It is upon the characters afforded by the presence or absence, and situation of these eyes,\nthat Ehrenberg has constructed his genera of Rotifera. These eyes have been attacked from many quarters. Morren has seen their red colour distributed over the whole body in various Polygastria. Dujardin objects that they are present in some species and absent in others ; that they enlarge and decrease, or disappear altogether with age. Rymer Jones says, that they possess no organisation that would lead us unhesitatingly to designate them organs of vision. At the same time, the resemblance between these eve-specks and those of the Medusae and the Mollusca, which are admitted to be organs of vision, would still, we think, give the balance of probabilities in favour of regarding these red spots as true rudimentary eyes. If then we may regard these red spots as eyes, the masses near them, on the same grounds, may be looked upon as associated nervous ganglia.\nReproductive system. \u2014 Although all observers are agreed that the Rotifera are truly hermaphrodite, they have not agreed upon the functions of many parts supposed to belong to the reproductive system. The female organs consist of an ovigerous sac or ovary, which exists very generally in the family (fig. 294. c ; fig.289. d, d; fig. 296. c;fig. 303. i ; fig. 292. ff). It is sometimes a simple sac, at others provided with two projecting processes, terminating by a narrow opening in the common cloaca. In some cases the ovary produces but one ovum ; in others there are several ova. Sometimes the young burst the shell before they leave their parent, as in the Rotifer vulgaris. In the Hydatina senta and others, the eggs are deposited some hours before the young are hatched.\nThe development of the ova can be seen with great distinctness through the transparent shells of many of the Rotifera. Ehrenberg has detailed this process as it occurs in the Hydatina senta. At first the ova are seen as little vesicles filled with a glairy fluid, probably albumen. In the course of a few hours a dark speck is seen in the vesicle, which may be called the yolk (fig. 303. n). In this state the ovum becomes fecundated, and is extruded from the cloaca. Three hours after extrusion the germinal vesicle, which had before been pushed to one side by the yolk,disappears, and the yolk occupies the whole of the egg. Six hours after extrusion, a dark spot appears upon the yolk, which can be discerned to be the head of the young animal with its masticatory apparatus. In eleven hours the rotatory organs are developed, and their cilia beginning to work, the young creature moves about in its shell. At the end of twelve hours the movements become so powerful as to burst the shell.\nAccording to Ehrenberg, the male organs consist, first, of a series of tubular prolongations, some of which we have seen are covered with the tremulous gills, and, second, of vesicles which are capable of contracting. In some cases the tubes are present without the vesicle ; in other cases, as in Ptygura meli-certa (fig. 288. a), the vesicles a reseen but not the tubes. Those who regard these as a male","page":414},{"file":"p0415.txt","language":"en","ocr_en":"SALIVA.\n415\napparatus, suppose that the spermatic fluid is secreted in the tubes, and passed on to the vesicle, where it is projected into the cloaca, and fecundates the ovum. The constant contraction of the vesicle seems opposed to the view that its function is that of merely fecundating the ovum, and Dujardin thinks it is connected with the function of respiration. Hitherto no spermatozoa have been found in these organs, although Doyere states that he has found zoospores in the tardigrade Infusoria. The spermatic tubes are seen in Rotifer vulgaris (fig. 299. i, i), in Hydatina senta (fig. 293. h), and Notommata myrmeleo (Jig. 303. f,g).\nAfter the extrusion of the ova from the cloaca in many species, they are attached to the lorica, as in Brachionus pala (fig. 296,/.), in the same way as in some Crustacea. The rapidity with which the ova are produced is very great ; and one individual, in the course of a few days, will be the parent of many millions. Their reproductive powers, however, are small compared with those of Polygastria.\nIn this brief sketch we have occasionally alluded to the affinities of the Rotifera, and we think that there can be little doubt, that these are decidedly with the Articulata, standing perhaps between the cilio-branchiate Polyps on the one side, and the Cirrhopoda on the other. Ehrenberg has summed up the general relations of these creatures in the following manner. They are\nPolygastria, with a single intestinal canal, without the power of spontaneous fission.\nAcalepha, with a simple intestinal canal, and rotatory organs.\nNematoid worms, with rotatory organs and\nunited sexes.\nBryozoa, without gemmiparous reproduction.\nMollusca, without vascular pulsations.\nEntomostraca, without pulsation or articulated feet, and hermaphrodite reproduction.\nFishes without a backbone or a heart, and with rotatory organs and united sexes.\nBibliography. \u2014 Leeuwenhoek, Philosophical Transactions, 1701\u20141704. Baker, Employment of the Microscope. London, 1753. Bory St. Vincent, Dictionnaire Classique d\u2019Histoire Naturelle, art. Rotiferes. Ehrenberg, Infusions-thierchen. Berlin, 1838. Pritchard, Infusoria, living and fossil. London, 1845. Doyere, Memoire sur les Tardigrades ; Ann. des Sc. Nat. 1842. Owen, Lectures on Comparative Anatomy, vol. i. London, 1843. Grant, Outlines of Comparative Anatomy. London, 1843. T. Bymer Jones, A general Outline of the Animal Kingdom. London, 1841. Dujardin, Histoire Naturelle des Zoophytes, Infusories. Paris, 1843 ; Report on the Progress of Zoology, 1842, published by the Ray Society. Oken, Phisio-Philosophy, Ray Society, 1847. Mantell, Thoughts on Animalcules. London, 1846. Carpenter, Cyclopaedia of Natural Science. London, 1847.\t(Edwin Lankester.)\nRUMINANTIA. (See Supplement.)\nSALIVA (la Salive, Fr.; der Speichel, Germ. ; la Sciliva, Ital.). \u2014 The saliva is a fluid secreted by a series of glands placed about the maxillary region. These glands,\nviz. the parotids, submaxillaries, and sublingual s, pour their secretions into the cavity of the mouth on either side. In consequence of this arrangement, it has always been a matter of difficulty to obtain saliva in a perfectly pure state, the secretion of the mouth interfering, by admixture, with the exhibition of the natural qualities of the saliva, and more especially with its microscopic characters. It occasionally happens that the fluid can be obtained more directly from the gland in cases of salivary fistula affecting the parotid duct, but it is to be doubted whether we ought to look for the secretion in its normal state in such instances. No attempts have, as yet, been made to determine whether or not saliva, as obtained from the different glands, is identical in character ; but so far as general observation guides us, there appears no variation in its constitution as secreted from these different sources.\nQuantity.\u2014The quantity of saliva secreted during the day has never been very accurately ascertained. It has been said that about twelve ounces are produced during the twenty-four hours, but it is highly probable that much more than this is excreted by the adult in health. The data for the statement above mentioned are most imperfect. Mitscherlich made experiments on a patient suffering from fistula of the stenonian duct, and succeeded in obtaining about 2\u00a3 ounces troy of saliva from the one parotid in twenty-four hours. The saliva collected during the same time from the mouth amounted in this experiment to six times more than that collected from the one gland : we may, therefore, conclude that the subject of this experiment was secreting from 16 to 20 ounces troy of saliva during the twenty-four hours. Mitscherlich observed that when the nerves were not excited by the motion of the muscles of mastication, or of those of the tongue, no saliva flowed, but that motion of these parts induced secretion.\nThe presence of food in the mouth caused a rapid flow of saliva, which was more especially noticed when the first portions were introduced. Long mastication appeared to cause excessive secretion, and the more stimulating the nature of the food, the larger was the quantity of saliva produced.\nThe uses of the saliva will be best considered when we have described its general qualities.\nPhysical qualities. \u2014 The constitution of saliva has been investigated by several chemists. It possesses the following general physical characters : \u2014 When freshly obtained from the mouth it is opalescent, viscid, and colourless. It separates by rest into an upper stratum of clear fluid, and a lower portion made up of the same fluid in admixture with epithelium scales and mucus. Under the microscope, saliva shows the presence of epithelium scales swollen mucus globules, and substances of various forms, apparently shreds of scales and ruptured cells. There are also fatty particles, varying in size, and bright granules. Some of the mucous","page":415},{"file":"p0416.txt","language":"en","ocr_en":"416\nSALIVA.\nglobules are remarkably transparent, and smaller than the more opake.\nSpecific gravity. \u2014 The specific gravity of healthy saliva is about 1007*9, according to the experiments of Dr. Wright. It is denser after food has been taken. Mitscherlich gives the specific gravity of saliva at 1006*1 to 1008*8, which agrees with Dr. Wright\u2019s observations.\nSome discrepancy of opinion exists as to the reaction of saliva in respect to alkalinity or acidity. Tiedemann and Gmelin, and also Schultze, state fresh saliva to be alkaline. The latter chemist, has, indeed, attempted to define its saturating power. He also considers that it may become acid if retained long in the mouth, and that its alkalinity when fresh is dependent on ammonia. This is denied by Mitscherlich, who says that no ammonia is given off when fresh saliva is heated, and that the alkalinity depends on the presence of a fixed alkali.\nI have myself found that saliva, so far from losing its alkalinity by evaporation, has this quality increased, and am inclined to regard the reaction as dependent on the presence of tribasic phosphate of soda (a salt reacting on test paper as an alkali), as has been stated by Enderlin.\nChemistry.\u2014Berzelius estimates the solids of saliva at about 1 per cent. From the solid residue he extracted osmazome, an alkaline lactate, and chlorides of potassium and sodium by digestion with alcohol. That portion which the alcohol left undissolved consisted of soda, mucus, and a peculiar animal matter, which has been called \u201c salivary matter,\u201d or \u201c ptyalin.\u201d The mucus can be separated from this salivary matter and soda by digestion in cold water, which dissolves the two latter. The mucus thus separated by Berzelius yielded on incineration a large proportion of phosphate of lime.\nThe following is his analysis of saliva : \u2014\nWater.......................... 992*9\nPtyalin...........................2*9\nMucus -\t-\t-\t-\t-\t14\nAnimal extractive matter and alkaline lactates\t-\t-\t-\t*9\nChloride of sodium\t-\t-\t1*7\nSoda...............................*2\n1000*0\nTiedemann and Gmelin obtained from 1*14 to 1*19 percent, of solid residue by evaporating saliva. From this, 0*25 parts of ash were obtained, of which 0 203 were composed of salts soluble in water, the remainder consisting of earthy phosphates.\nThe following is a list of the constituents of the saliva, according to the above-mentioned chemists : \u2014\n1.\tWater.\n2.\tA substance soluble in alcohol, and insoluble in water (fat containing phosphorus).\n3.\tMatters soluble both in alcohol and water (osmazome, chloride of potassium, lac-\ntate of potash, and sulpho-cyanuret of potassium.\n4.\tAnimal matter soluble in boiling alcohol, but precipitated during cooling, with sulphate of potash and some chloride of potassium.\n5.\tMatters soluble in water only (salivary matter with abundant phosphate, and some sulphate of an alkali, and chloride of potassium).\n6.\tMatters soluble neither in water nor in alcohol (mucus, probably some albumen, with alkaline carbonate, and phosphate).\nMitscherlich gives the following analysis of the saline ingredients of saliva :\nChloride of potassium - percent. 0*18 Potash (in combination with 1\tn.\u2122.\nlactic acid). -\t- j 0094\nSoda..............................0*024\nLactic acid -\nSoda (combined with mucus) - 0*164 Phosphate of lime -\t0*017\nSilica ----- 0*015 Simon made an analysis of his own saliva, and gives the following as the result :\nFat containing cholesterine -\t0*525\nPtyalin with extractive matter -\t4*375\nExtractive matter and salts -\t2*450\nAlbumen, mucus, and cells -\t1*400\nWater.......................... 991*225\nSimon* adopted the following process in order to complete the above analysis. A known weight of saliva was first evaporated to dryness ; the loss of weight thus indicated the proportion of water. The residue was treated with ether, which extracted the fats. The solid mass remaining was next treated with water, which dissolved out the ptyalin, extractive matters, and salts, leaving behind mucus, albumen, and cells.\nDr. Wright has experimented on saliva most industriously, and has entered at some length on the peculiarities of ptyalin, but evidently speaks of a very different constituent to that described by Berzelius and Simon. According to the mode of analysis adopted by these two latter chemists, the ptyalin of Wright will be estimated with the fatty constituents, among which it most probably holds its proper place.\nHis process of extraction is as follows :\u2014\u201c To pass saliva through ordinary filtering paper, and after filtration shall have been completed, to exhaust the residue with sulphuric ether ; the ethereal solution contains a fatty acid and ptyalin. It is to be allowed to evaporate spontaneously, and the residue left by evaporation is to be placed upon a filter and acted upon by distilled water, which dissolves the ptyalin and leaves the fatty acid. If the aqueous solution be carefully evaporated to dryness, the salivary matter will be obtained in a pure state. Ptyalin, thus prepared, is a nearly solid matter, adhesive, and of a yellowish colour ; it is neither acid nor alkaline, readily\n* In framing this article, much valuable information has been derived from Simon\u2019s work on Physiological and Pathological Chemistry, translated by Dr. Day for the Sydenham Society.","page":416},{"file":"p0417.txt","language":"en","ocr_en":"SALIVA.\t417\nsoluble in ether, alcohol, and essential oils, but more sparingly soluble in water. It possesses the odour of saliva, and is precipitated by diacetate of lead, nitrate of silver, and slightly by acetate and nitrate of lead, and by tincture of galls ; neither bichloride of mercury nor the strong acids precipitate it. The latter decrease its solubility, and heighten its odour, while alkalies render it more soluble, and give it the odour of mucus. Ptyalin, when pure, may be kept a length of time, at a moderate temperature, without undergoing decomposition.\u201d\nAccording to Dr. Wright, saliva possesses the property of absorbing oxygen gas, and he states that he has known as much as 2*25 times the bulk of the saliva to be taken up. This quality varies, however, in different specimens ; in Dr. Wright\u2019s opinion, according to the quantity of carbonic acid gas contained in the secretion.\nHe states he has succeeded in obtaining oxygen from saliva by applying heat, and considers its presence of great value in assisting the action of the secretion during the process of digestion, inasmuch as he found that, after exposing saliva to oxygen, so as to enable it to absorb the gas freely, he was enabled to convert, by its use, a much greater quantity of starch into sugar and gum (an action of which I shall hereafter treat), than by using saliva which had not been exposed to oxygen.\nDr. Wright\u2019s analysis of saliva is as follows :\nWater -----\t988*1\nPtyalin............................18\nFatty acid -\t-\t-\t*5\nChlorides of potassium and sodium\t1*4\nAlbumen combined with soda -\t*9\nPhosphate oflime\t*6\nAlbuminate of soda\t*8\nLactates of potash and soda -\t*7\nSulphocyanide of potassium -\t*9\nSoda -----\t-5\nMucus, with some ptyalin -\t-\t2*6\nL\u2019Heritier made analyses of saliva as obtained from healthy persons, and gives the following as a mean of ten observations on adults :\nWater -\t-\t- 986*5\nOrganic matter -\t- 12*6\nInorganic matter -\t-\t*9\nOf the organic matters 2*5 parts consisted of salivary matter, or ptyalin (probably not the ptyalin of Dr, Wright, but that described by Berzelius and Simon).\nSaliva of Children. \u2014 Observations by L\u2019Heritier on the saliva of children showed the quantity of water to be greater in early life. He gives the following as the mean of four analyses :\nWater -\t996*0\nOrganic matter -\t-\t3*5\nInorganic matter\t*5\nThe ptyalin contained in the organic matter amounted to only 1*1.\nVOL. iv.\nMale and Female Saliva.\u2014L\u2019Heritier states that he could detect no difference between the saliva of men and women.\nEnderlin has made several analyses of the ashes obtained from different specimens of saliva, and has found them to be similarly constituted.\nIn his opinion, the tribasic phosphate of soda it contains is valuable as a solvent of the protein compounds. He denies the existence of alkaline lactates, not only because the ashes of saliva yielded no carbonate in his experiments, but because he failed in detecting them by direct observation before incineration. His analyses of the ashes of saliva, as obtained from a large quantity of the secretion from different persons, yielded the following result\nTribasic phosphate of soda -\t-\t28*122\nChlorides of potassium and sodium -\t61*930\nSulphate of soda -\t2*315\nPhosphate of lime\nPhosphate of magnesia J-\t5*509\nPeroxide of iron J\nThe existence of the sulphocyanide of potassium in the saliva is a matter of importance, and some difference of opinion is observed among chemists on the subject. The discovery was originally announced by Trevi-ranus, who noticed that saliva, when mixed with a neutral solution of the peroxide of iron, produced a dark red colour. This he regarded as produced by an acid, to which the name of \u201cacid of the blood\u201d had been given by Winterl, and which was afterwards known as the sulphuretted chyazic acid of Porrett. Tiedemann and Gmelin examined into this question, and found that the reaction described by Treviranus really occurred on adding persalts of iron to saliva, and made experiments to discover whether the colouration was produced by a sulphocyanide. After lengthened observation, these physiologists arrived at the conclusion that such was the case, and procured other reactions besides such as were obtained by testing with iron, which satisfied them of the presence of sulphocyanogen.\nDr. Wright mentions sulphocyanide of potassium in his analysis of saliva, and states that its quantity is always increased by locally stimulating the salivary glands, as by smoking or chewing sialogogues. The internal use of prussic acid or salts containing cyanogen increases its quantity. It is also greatly increased by the use of sulphur. Dr. W. says the presence of this salt is best detected in the alcoholic extract obtained from dried saliva. The sulphocyanide of potassium constitutes, according to his observations, from 0 051 to 0*098 of the secretion. Kuehn tried to detect the presence of a sulphocyanide in saliva, but failed. He could not prove the presence of sulphur either by the processes of Gmelin or Ure. M\u00fcller, also, was not satisfied by his observations that the red colour produced in iron resulted from the presence of sulphocyanogen.\nE e","page":417},{"file":"p0418.txt","language":"en","ocr_en":"418\tSALIVA.\nThe properties and physiological uses of the saliva have been examined into by a great number of observers, and we find much valuable and curious matter for consideration in their general results.\nGeneral Properties. \u2014 B'oerhaave and Hoffman ascribed a peculiar fermentative power to saliva, a subject which was subsequently more fully entered upon by Sir John Pringle and Dr. Macbride. The former observer experimented on certain anti-putrescent qualities of the secretion, and found that raw meat putrefied slower after admixture with saliva. Another experiment of Sir John\u2019s deserves description in detail. He took two drachms of fresh meat, and the same quantity of bread, and to these added as much saliva as he supposed might be necessary for digestion. He beat up this mixture in a mortar, then enclosed it in a phial, and set it in a warm atmosphere for about two days. No signs of fermentation could be detected at the end of that time, but during the third day the bread and flesh rose in the water, a sediment formed, and bubbles were observed mounting in the liquor. The mixture now possessed a vinous smell. This action was observed to continue about twice as long as in a similarly conducted experiment made without saliva. In the former case the fermentation was more gradual, and when complete the mixture possessed a pure acid flavour, and had no disagreeable smell.\nNotwithstanding that the subject has been laboriously investigated by some of the most ingenious experimenters of the day, the uses of the saliva in the economy are evidently still but imperfectly ascertained. Spallanzani was inclined to believe in a solvent action which this fluid was capable of exerting on animal matters, and thought that food, when inclosed in a tube perforated with numerous small holes, and placed in saliva, was more rapidly broken up and dissolved than when water only was used. The further observations of Berzelius and M\u00fcller tended, however, to impugn the correctness of this opinion, pure water acting, according to their experiments, quite as efficiently as saliva.\nSome experiments have been made by Hiinefield, by which he thinks he has shown saliva to possess a peculiar action on fibrin : this, however, requires confirmation. In the year 1831 Leuchs made a most important discovery in connection with the history of saliva, viz., that when boiled starch is added to it, and the mixture is kept at a temperature of 98\u00b0, the starch becomes converted into sugar. This action has been since investigated by Mialhe, who attributes the phenomenon to the presence of a peculiar proximate principle existing in saliva, to which he has given the name of animal diastase, in consequence of its possessing the qualities of that principle as it exists in the vegetable kingdom, in germinating seeds. In order to obtain this substance the saliva is to be filtered, and then precipitated by the addition of absolute alcohol, of which generally from five\nto six times the weight of the saliva are required to effect the purpose. The animal diastase falls in the form of a flocculent precipitate, which may be collected and dried on a filter. It forms about 0\u20182 of the whole saliva. It is a white substance, insoluble in alcohol.\nA series of experiments have been lately made by M. Bernard, with a view of determining what the action of saliva may be in the digestive process.\nHe first satisfied himself that the saliva of the horse and the dog, as well as that from the human subject, possessed the property of decomposing starch into sugar, under the conditions of temperature above described. The saliva of the dog, however, effected the conversion but slowly, that of the horse more quickly, but neither nearly with the rapidity of human saliva. The dog\u2019s saliva required nearly eight times as long as that from man, and that of the horse nearly four times as long. Care was taken in these experiments to employ the same quantities of saliva and of starch.\nPure saliva, obtained from the parotid and submaxillary glands of the dog, were found by Bernard quite incompetent to effect the transformation of starch. This agrees with the observation of Lassaigne, who found that pure saliva from the parotid of horses possessed no transforming power of the kind, though mixed saliva taken from the oesophagus acted well on starch. According to Bernard\u2019s experiments, the explanation of this rests on the fact that the power of transformation is a property of the secretion from the mucous membrane lining the mouth, for on placing layers of that membrane in contact either with starch or sugar he obtained decomposition, and lactic acid was produced. He thus reduces the importance of saliva, as an adjunct in digestion, to little more than that of a lubricating fluid.\nSaliva of Animals. \u2014 The saliva of animals has not been much experimented upon. Berzelius remarks as follows on the saliva of the dog * : \u2014 \u201cAs obtained from the parotid, it is a pale yellow fluid of mucilaginous consistence, resembling white of egg in its physical characters. It leaves 2\u201958 per cent, of solid matters on evaporation. These solids form a transparent pale yellow varnish on the surface of the evaporating dish, which becomes moist by exposure to air. Alcohol extracts principally chloride of sodium from this mass, and, by evaporating the alcoholic solution, crystals of the chloride can be obtained nearly in a pure state, being, however, mixed with a small proportion of a yellowish substance, composed principally of lactate of soda and os-mazome. Sulphocyanogen cannot be detected with certainty in the alcoholic extract, and but a trace only of its reaction with the salts of iron can be observed.\nThe portion of solid matter which is in-\n* Trait\u00e9 de Chimie, vol. yii.","page":418},{"file":"p0419.txt","language":"en","ocr_en":"SALIVA.\nsoluble in alcohol contains salivary matter, combined with soda, and its reactions accord perfectly with those of the salivary matter found by Gmelin in human saliva. Phosphate of potash, phosphate of soda, and a small proportion of carbonate of lime, also exist in this saliva.\nThe saliva of the sheep, according to Berzelius, is clear, and not adhesive, like that of the dog. It has a feeble saline taste, and a faint alkaline reaction. When dried, it leaves P68 per cent, of solid matter, which forms an opaque white membrane, and becomes moist by exposure. Chloride of sodium is extracted from this mass, in octahedral crystals, by digestion with alcohol. The salts of iron yield ample evidence of the presence of sulpho-cyanogen in the alcoholic solution. The portion of solid matter insoluble in alcohol, when treated with water, yields little else than salts. So completely is this the case, that the evaporated aqueous solution scarcely gives out an empyreumatic odour while being heated to redness. The mass, which is insoluble both in water and alcohol, is brittle and membranous, insoluble in acetic acid, and not gelatinised when moistened by it. The acid, however, dissolves out phosphate of lime, after which it is pr\u00e9cipitable by the addition either of ammonia or oxalate of lime, but not by infusion of galls.\nThe following is an analysis of the saliva of the sheep : \u2014\nWater -----\t98*90\nMatters soluble in alcohol (extract of meat, a matter which crystallises chloride of sodium in octahedra, chloride of sodium, and a small proportion of sulphocyanide of sodium).\t.\t0*11\nMatters soluble in water only (traces of ptyalin, a considerable quantity of phosphate of soda and chloride of potassium, and carbonate of soda) -\t-\t0'82\nMatters insoluble in water and alcohol (mucus or coagulated albumen, and a small quantity of phosphate and carbonate of lime)..........................0*05\nThe peculiar quality possessed by saliva of becoming mucilaginous and adherent, was attributed by Tiedemann and Gmelin to a solution of mucus in alkaline carbonate. This last is present in the saliva of the sheep in such abundance, that when dry it effervesces on the addition of acids. The saliva of the dog, however, contains most, and the saliva of man the smallest quantity of the salt. According to Tiedemann and Gmelin, the alkaline carbonate of human saliva is a potash salt, while the saliva of the dog and sheep contains carbonate of soda.\nThe alkaline phosphate contained in saliva exists in larger proportion in that of man, and of the sheep, than in that of the dog. All three contain chloride of sodium in large\n419\nquantity. The sulphocyanide which exists in the saliva of man and of the sheep cannot be satisfactorily detected in the dog. Ptyalin is almost wanting in the saliva of the sheep, while that of the dog is deficient in animal extractive matter.\nLassaigne and Leuret found the same quantity, viz. about one per cent, of solid matters, in the saliva of man, the horse, and the dog.\nThe saliva of insects has been collected by Reuzzer*, but not in quantity to admit of analysis. It was found, however, to yield an alkaline reaction.\nSALIVA IN DISEASE.\nSalivary Calculi. \u2014 As the result, in all probability, of some defect in secretion, the saliva occasionally gives rise to the formation of calculous matter. Thus, what is commonly called tartar, tends to deposit upon the teeth. Berzelius has examined this substance, and found that water extracted ptyalin from it, and that the remainder was soluble in hydrochloric acid, only a small residue composed of mucus being left unacted upon. Caustic ammonia precipitated phosphate of lime, and ammo-niaco-magnesian phosphate from the acid solution.\nAnalysis yielded the following result : \u2014\t\nPtyalin\t-\t- P0\nSalivary mucus -\t- 12*5\nEarthy phosphates\t- 79-0\nAnimal matter soluble in\thydro-\nchloric acid\t-\t7*5\n\t100-0\nYauquelin and Langier found one of these masses to contain\nWater ----- 0'07 Salivary mucus insoluble in acids and in water -\t-\t-\t- 0*13\nPhosphate of lime, with traces of magnesia -\t0'66\nCarbonate of lime -\t0*09\nAnimal matter soluble in hydrochloric acid\t-\t-\t-\t- 0*05\nSalivary calculi only occasionally occur in the human subject, but are frequently observed in animals. One of these substances from the human subject yielded, according to the analysis of Poggiale, 94 per cent, of phosphate of lime, the remainder being mucus and other animal matters. Wurzer found, in a concretion from the submaxillary gland of a man, carbonate of lime, earthy phosphates, oxide of iron, and manganese.\nCalculous concretions, obtained from the salivary ducts of the horse and ass, have been analysed by Lassaigne, Henry, and Caventon, with the following results : \u2014\n* Physiol. Untersuch, \u00fcber die thierische Haushaltung der Insecten. T\u00fcb. 1817.\nE E 2","page":419},{"file":"p0420.txt","language":"en","ocr_en":"420\nSALIVA.\n\tCaventon.\tLassaigne.\tHenry.\n\tThe Ass.\tThe Horse.\tThe Horse.\nCarbonate of lime - Carbonate of magnesia -Phosphate of lime - Animal matter -Water -\t91-6 4-8 3-6\t84 3 91 3J\t85-52 7-56 4-40 2-42\n\t100-0\t99\t99-90\nRanula.\u2014The disease called ranula, which was long supposed to depend upon the detention of saliva within the salivary duct, owing to inflammatory closure of its orifice, and the distention consequent upon such condition, has been lately shown by Dr. Goruss Besanez* to depend on the development of an encysted tumour within the duct. The fluid evacuated from ranula has been analysed by him, and its composition determined as follows : \u2014\nWater\t-\t95'029\nTraces of fat and chloride of\nsodium\t-\tT062\nAqueous extractive matter - 0\"923 Albuminate of soda -\t- 2\u2019986\nThis analysis shows the contained fluid of ranula to differ entirely from saliva, and places it among the products of morbid secreting sacs. Under the microscope, blood corpuscles and inflammatory exudation corpuscles were observed, none of the ordinary characters of saliva appearing. Much curious information has been collected by Dr. Wright with regard to the morbid conditions of saliva, and the production of hydrophobic disease. Among the statements made by various authors are the following, f\nHydrophobia. \u2014 Ambrose Par\u00e9 agrees with Galen and Dioscorides in the opinion that morbid saliva may produce hydrophobia by contact with the second skin. The disease is stated by Ccelius Aurelianus to have been communicated to a sempstress who used her teeth to unsew the cloak of a hydrophobic patient. Schenckins states hydrophobia to have been communicated by a sword which had been used some years before for the purpose of destroying a rabid dog. Palmarius relates that a peasant rendered his children rabid by kissing them.\nMagendie and Breschet succeeded in producing hydrophobia in a dog by inserting the saliva of a rabid man under the skin of the animal. Dr. Herturch found that out of fifty-nine trials, only fourteen animals became affected with real rabies. Mr. Youatt succeeded in causing hydrophobia in a healthy dog by inserting as a seton-cord a piece of\n* Heller\u2019s Archiv f\u00fcr Phys, mid Patholog. Chemie und Mikroskopie, vol. ii.\nt See Dr. Wright\u2019s communications to the Lancet, 1844.\nsilk moistened in the mouth of a hydrophobic animal. There appears but little doubt that hydrophobia is really a disease produced by a morbid poison circulating in the system ; nor does the long period which occasionally elapses between inoculation and the development of the disease in any way militate against the correctness of such a view, for we are aware, from the history of other well-recognised morbid poisons, how various the period required for development of action is; probably bearing some relation to the temperament and general habits of the subject affected.\nDr. Wright believes that there is no chemical difference (or, rather, none admitting of detection) between healthy saliva and that secretion which is capable of producing hydrophobia. He has succeeded in producing rabies by injecting healthy saliva into the veins of animals, and it appears probable from his observations, that the difference between saliva capable of producing hydrophobia, and the fluid in its normal state, must be regarded rather as one of degree than in kind.\nInfection.\u2014Saliva is said to have produced disease by contact in a variety of ways ; with how much truth appears most uncertain, but the following statements are related as matters of fact :\u2014\nSyphilis is said to have been communicated by kissing, and by the morbid saliva adhering to a drinking cup. Lassius, Wedelius, and Victor Schneider are of that opinion. Phthisis, according to Bernhard Gladbach, has been communicated by means of the saliva ; and scurvy, also, according to Rolfincius, Senner-tus, and Michael. Ledelius states that an old woman infected a boy with ague by giving him bread to eat which she had previously mumbled. Many other equally strange and disgusting statements of this kind have been put forth by old writers, which show little else than the imperfect method of inquiry which satisfied the older investigators, and a lamentable inclination on their part to regard coincidences as of necessity bearing the relation of cause and effect.\nThe saliva is stated to become coloured occasionally, but the subject requires further investigation. Drs. Thomson and Christison have noticed it of a blue colour under the use of lead, and Dr. Wright says that ordinary medicinal doses will produce that effect. The same observer has noticed a deep blue coloured saliva in purpura and advanced stages of fever, and is of opinion that prussian blue is the cause, but has not yet examined the point. Great acridity of saliva has been observed in maniacal patients. Dr. Wright has recorded that such saliva is sometimes so irritating as to be capable of excoriating the hand when applied to it.\nChildren\u2019s saliva may become so acrid as to excoriate the nipples of any nurse who may suckle them.\nMercurial Salivation. \u2014 Simon has obtained acetic acid from saliva discharged during salivation, and believes it may also exist in rheu-","page":420},{"file":"p0421.txt","language":"en","ocr_en":"421\nSALIVA.\nmatism. Donn\u00e9 says the saliva becomes acid in many forms of disease. Brugnatelli found oxalic acid in the saliva of a phthisical patient. The following is Simon\u2019s analysis of the saliva of mercurial salivation (it contained acetic acid which was volatilised during evaporation) :\nWater............................ 974T2\nYellow viscid fat\t-\t-\t6\u201894\nPtyalin, extractives, and traces!\nof casein\tJ\nAlcoholic extractives, and salts -\t7\u201857\nAlbumen -\t7*77\nThis saliva, therefore, differed from that of health in containing excess of solid constituents, arising from excess of fatty matter, extractives, albumen, and salts. The ptyalin remains much as in health.\nL\u2019Heritier gives the following as the mean of three analyses of the saliva in mercurial salivation.\nWater -\t- - 970\u20180 instead of 986-5 health.\nOrganic matters 28-6\t\u201e\t12*6\nInorganic matters 1*1\t\u201e\t1\u20189\nL\u2019Heritier, like Simon, found no great variation in the amount of ptyalin.\nDr. Wright found a great increase in the quantity of mucus contained in the saliva during mercurial salivation. He could not detect mercury in the secretion. His analysis is as\nfollows :\u2014 Water\t-\t\t- 988-7\nPtyalin -\t-\t1-9\nFatty acid\t-\t-\t0-4\nAlbuminate of soda -\t-\t- 0-6\nMucus, with a trace of ptyalin\t\t.\t3-8\nLactates Phosphates\tpotash\t} \u00ab\nHydrochlorates\tr oUUfl lime\t\nFlydrosulphocyanate J\t\t\nGmelin found a considerable variety in the saliva of patients who had been salivated by mercurial inunction. In one case a large quantity of fat was detected by him. He obtained mercury from this saliva.\nSpontaneous Salivation. \u2014 The saliva of spontaneous salivation has been examined by Vogel, who found it constituted as follows :\u2014 Water -\t-\t-\t- 99L2\nPtyalin, osmazome, fat, and !\t...\nalbumen -\t-\t- J\nSalts of soda, potash, and lime 4\" 4\nThis shows no great variation from the natural standard.\nMitscherlich and Guibourt, who also examined the saliva of spontaneous salivation, found no increase in the solid constituents, while the sulphocyanogen and ptyalin were deficient.\nSimon examined the saliva of a patient suffering from inflammation of the pancreas (?). It was a clear viscid fluid secreted in great abundance. It contained mucus, and was of alkaline reaction. Its specific gravity was 1005.\nUnder the microscope, numerous oil vesicles were visible, besides ordinary mucus,\nglobules, and epithelium scales ; 1000 parts of this saliva yielded 10 parts of solid matters.\nL\u2019Heritier examined the saliva of chlorosis, and found it to suffer from watery degeneration, in the same manner as the animal tissues and secretions generally.\nIn dropsy, with albuminous urine, the saliva was found by L\u2019Heritier\tto contain,\nWater -\t-\t-\t985'9\nOrganic matter\t-\t-\t13\u20186\nInorganic matter -\t-\t\"5\nThe amount of water contained in saliva appears to diminish in inflammatory affections. The following is a mean result obtained from six analyses made on the saliva of cases of inflammatory fever, pneumonia, and erysipelas : Water -\t-\t-\t968-9\nOrganic matters\t-\t-\t30-0\nInorganic matters\t-\t1 \u2022 1\nThe proportion of ptyalin was found increased.\nScherer analysed the saliva of a girl suffering from a scorbutic affection of the mouth. There was a large secretion, forty ounces flowing in the twenty-four hours. It was fetid and alkaline, and of specific gravity 1004.\nAnalysis yielded the following result :\u2014\nWater\t-\t-\t-\t9S8'8\nCasein -\t6\u20195\nFat -\t-\t-\t-\t0-6\nExtractive matter and ptyalin 1*8 Carbonate of soda\t-\t-\t1*2\nChloride of sodium\t-\t-\t0'7\nPhosphate of lime\t-\t-\t0\u20184\nConfervoid growths and infusoria were detected in this saliva as taken fresh from the patient.\nA specimen of saliva from a phthisical patient was examined by L\u00e4nderer*, who found it to contain a great number of small fat globules aggregated into a viscid mass. These globules exhibited the properties of oleic acid.\nSeveral kinds of diseased saliva have been analysed by Dr. Wright, and I shall subjoin his analyses.\nFATTY SALIVA.\nWater\t-\t- 987-4\nPtyalin - Adventitious fatty matter and\t\u20227 }\t3-9\nfatty acid\t-\t\nAlbuminate of soda\t-\t1-5\nSulphocyanide of potassium\t- a trace\nMucus\t-\t-\t2-4\nLactates\t- f potash Hydrochlorates - -! soda Phosphates\t- (lime\tJ\t1-8\nSWEET SALIVA.\t\nWater\t-\t- 986-9\nPtyalin -\t*3\nFatty acid\t-\t\u20222\nMuco-saccharine matter\t-\t5-6\nAlbuminate of soda -\t\u20224\nSulphocyanogen\t- a trace\n* Heller\u2019s Archiv. 1846, p. 297.\nE E 3","page":421},{"file":"p0422.txt","language":"en","ocr_en":"422\nSALIVARY GLANDS.\nMucus, with trace of ptyalin -\t2*6\nLactates\t- f potash 1\nHydrochlorates -1 soda V -\tT9\nPhosphates - [lime J An excessive sweetness of the saliva has been observed in some cases of phthisis. It was an indication to which some importance was attached by the late Dr. Cholmeley, of Guy\u2019s Hospital.\nBILIOUS SALIVA.\nWater -----\t986*7\nPtyalin -----\t0*5\nFatty matter and fatty acid -\t-\t1*3\nBiliary matter -\t-\t-\t-\t3*2\nCholesterine -\t0*4\nAlbuminate of soda -\t-\tP9\nMucus -----\t1*6\nCarbonates\t- f potash 1\nHydrochlorates - -{ soda [\t-\t2*3\nPhosphates\t- [ lime\tJ\nGELATINOUS SALIVA.\nDr. Wright considers this variety of saliva was known to Baglivi. He describes it as imperfectly transparent, dingy-looking, viscid, and tremulous when cold. It decomposes readily, and is above the natural specific gravity, being 1009 to 1010. It has a mawkish taste and greasy odour, giving no odour of ptyalin when heated. It contains that principle, as well as sulphocyanogen, however, though in smaller proportion than healthy saliva.\nGelatinous saliva is neutral, or faintly acid ; absorbing oxygen sparingly, and possessing but little digestive power. Dr. Wright considers it indicative of a depraved and debilitated state of system. He saw one instance in a case of scurvy, and another in a case of carcinoma uteri. The analysis is as follows : \u2014\nWater\t-\t- 987*2\nPtyalin\t-\t*6\nFatty acid\t-\t*8\nGelatine -\t-\t-\t3*6\nAlbumen and soda\t-\t-\t1*3\nSulphocyanogen\t-\t- a trace\nMucus\t-\t-\t2*5\nLactates\t- f Hydrochlorates - -|\t' potash \"j soda >-\t-\t1*7\nPhosphates\t- [ Loss\tlime J\t-\t2*3\nMILKY SALIVA.\nThis kind of saliva has been noticed by several authors. A case is related by Nuck in which, during four months, milky saliva was secreted by a woman who became gravid during lactation. When the flow of milky saliva commenced, an intumescence of the breast was observed to decline. Richard, speaking of milk fever (Ann. Clin, de Montpellier), says the malady occasionally terminates favourably by the occurrence of a salivation consisting of milky saliva. Other authors also have noticed the occurrence of milky saliva, in connection with a suppressed flow of milk from the mammary gland.\nDr. Wright describes milky saliva as white,\ncompletely opaque, neutral to test paper, and rendered curdy by acetic acid.\nURINARY SALIVA.\nThis variety of saliva has been described by Dr. Prout. The salivation occurred spontaneously. The patient suffered anorexia, and was weak, but otherwise healthy. The renal secretion was diminished, and the saliva had a urinous taste. It was opalescent, foamed when agitated, and was slightly ropy. Its specific gravity was 1005. It restored the blue colour to reddened litmus paper. The soluble salts of lead, mercury, and silver, caused precipitates when added to it, as did also the mineral acids. Dilute acetic acid caused a precipitate, but no further precipitate could be obtained by subsequent addition of a solution of ferrocyanide of potassium. Therefore no albumen was present. 1000 grains of this saliva, when evaporated to dryness at a temperature between 212\u00b0 and 300\u00b0, left 8*65 grains, which were composed as follows :\u2014\nAnimal matter peculiar to saliva - 3*33 Alcoholic extract, apparently \"I .-g similar to that from the blood J Sulphuric acid -\t0*90\nHydrochloric acid -\t0*75\nPhosphoric acid -\t-\t-\t- 0 06\nAlkali\u2014partly potash and partly 1 0.KK soda............................J d\n8-65\nIn this case, when the urinary secretion was restored by the use of diuretics, the salivary discharge was proportionally diminished.\n(G. Owen Rees.')\nTHE SALIVARY GLANDS {Les Glandes Salivaires, Fr. : Die Speichel-Dr\u00fcsen, Germ. ; Le Glandule Salivali, Ital.)\u201e A series of conglomerate glands, arranged in a curved manner, and following the circumference of the inferior maxilla from the posterior border of one side to that of the other, and pouring their secretion into the mouth by means of excretory ducts, are thus denominated. They present a distinctly lobulated granular appearance, the component lobes and lobules being more or less loosely connected together by areolar tissue derived from the surface, and which, though serving the purpose of an investing membrane, is not of a sufficiently definite character to constitute a distinct capsule. They have a yellowish or greyish-red appearance, and are thus at once distinguished from the soft structures with which they are in immediate connection, namely, the cellular membrane and the lymphatic glands, the former being perfectly white, and the latter pale brown.\nThey are three in number on either side, and are named from above downwards the Parotid, Submaxillary, and Sublingual, and have in the same direction a relation as to their size, the parotid having the largest, the sublingual the smallest, and the submaxillary an intermediate volume. Though usually separated from each other by a slight interval,","page":422},{"file":"p0423.txt","language":"en","ocr_en":"423\nSALIVARY GLANDS.\nthey not unfrequently impinge the one upon the other, the lower edge of the parotid appearing to be structurally connected with the posterior border of the submaxillary, and the latter forming a junction with the sublingual. An uninterrupted glandular chain then in these instances surrounds the lower jaw.\nThe saliva secreted by them is poured by the ducts of the two last into the floor of the mouth, and by the duct of the first into the posterior part of the side of the cavity between the cheek and the upper and lower dentar arches.\nThe Parotid Gland is so named from its situation in the immediate vicinity of the external ear (jrap\u00e0 near, and oti\u00e7 the ear). It fills up the space of the same name, and is consequently bounded in front by the posterior edge of the ramus of the lower jaw, behind by the meatus auditorius externus above, and the mastoid process, digastric and sterno-mastoid muscles below : internally by the styloid process and muscles attached to it, together with the internal and external pterygoid muscles : superiorly by the posterior or parotidean division of the glenoid cavity within, and the zygomatic process without : inferiorly by a line continued on a level with the lower border of the horizontal ramus of the jaw from its angle to the anterior border of the sterno-mastoid muscle. The dimensions and form of the gland can only be well ascertained after removing it from its various connections, and in so doing it will be found that its posterior surface adheres very strongly by condensed cellular membrane to the cartilaginous portion of the meatus auditorius externus, while from its inner edge will be observed a process extending between the styloid muscles and the internal pterygoid as far as the pharynx. A dense fibrous septum, the stylo-maxillary, constituting one of the fixed points of attachment of the deep cervical fascia, separates it usually from the submaxillary gland. It has a triangular or pyramidal form. The base, which is superficial and slightly convex, represents its external surface, and is covered over by a dense areolar tissue, known as the \u201cparotidfascia,\u201d from which the different processes which separate the component parts of the gland are observed to proceed. The apex is the deepest-seated portion of the gland, and is represented by the prolongation already alluded to. The gland is bent, as it were, upon itself from behind forwards, so that its anterior surface presents a deep vertical groove, corresponding with the convexity of the ramus of the jaw, which is consequently overlapped by it externally and internally, in the former situation extending to a greater or less degree over the masseter, in the latter over the internal pterygoid muscle, and stylo-maxillary ligament. The part overlapping the masseter externally gives off above a process which runs between the zygoma and the duct of the gland, is horizontal in direction, and somewhat triangular in form, and is known as the Accessory Parotid Gland or \u201c Soda Parotidis\u201d It varies as to size, extent, and relation with\nthe gland itself. It is ordinarily about two-thirds of an inch in length, a third of an inch in the longest part of its vertical diameter, and from one-sixth to one-eighth of an inch in thickness. It is generally, as it were, an offset from the body of the gland, and has no immediate connection with Steno\u2019s duct : at other times it is distinct from the body of the gland, and opens by one or more excretory ducts into this canal. It occasionally becomes hypertrophied when the body of the parotid itself is atrophied. Cruveilhier has observed two small accessory glands, one at the middle and the other at the anterior part of the masseter muscle. The parotid measures in a vertical direction from an inch and a half to two inches, from before backwards from an inch and a quarter to an inch and a half, and from without inwards about an inch. The lobes which enter into its composition are irregularly rounded, and considerably smaller than those of the submaxillary gland. They range from the one-eighth to the one-fifth of an inch in diameter ; and these again are constituted of lobules having an average diameter of about the fa of an inch, the smallest measuring T^T, and the largest about \u2014 inch across.\nThe relations of the external carotid artery, and its terminal branches, the external jugular vein, the facial and the anterior auricular nerve, and the further relative anatomy of the gland, have been already fully entered into.* We may mention, however, that in the substance of the parotid, i. e. in the cellular tissue between its lobules a little below the surface, are embedded one or more lymphatic glands which can at a glance be recognised from the structure of the parotid by their brown colour, smooth surface, and comparative density. These glands not unfrequently undergo morbid changes, and by their gradual enlargement cause progressive atrophy of the parotid itself, and ultimately assume its anatomical position. This circumstance constitutes therefore an important element in the inquiry as to the nature of any morbid growth occupying the parotid space, but which it would be out of place here further to allude to.\nThe Duct of the Parotid Gland, called also the Duct of Steno, emerges from above the middle of its anterior border, accompanied by several branches of the portio dura, runs horizontally forwards across the masseter muscle as far as its buccal border, passing about half an inch below the zygoma, and immediately below the accessory gland and transverse facial artery. Having reached the anterior border of the masseter, it curves over a mass of fat between it and the buccinator; forming then a very obtuse angle, it perforates the latter, and glides between it and the mucous membrane of the mouth, which it perforates opposite the second upper molar tooth.\nThis terminal oblique portion is about the fifth of an inch in extent, and has justly been compared by Cruveilhier to the vesical portion of the ureter, which, after having perforated\n* See Parotid Region.\nE E 4","page":423},{"file":"p0424.txt","language":"en","ocr_en":"SALIVARY GLANDS.\n42-1\nthe muscular tunic of the bladder, runs for the extent of an inch between it and the mucous membrane.\nThe parotid duct is from two and a half to three inches in length, and is covered over by a prolongation of the areolar tissue which forms the investment of the body of the gland. This can be distinctly traced as far as the point at which it perforates the buccinator, and here it is surrounded by an aponeurotic expansion derived from the tendon of that muscle, and by a series of glands continuous with the genial glands, the ducts of which open partly into it and partly into the mouth. Having removed the external cellular covering of the duct, its true middle or fibrous coat is observed, giving it a distinct opaque white appearance. It is strong, dense, and elastic. Its thinnest portion is over the oblique part of the duct that glides between the muscular and mucous lining of the buccal cavity, its thickest that covering that part of it between the buccinator and the masseter, the remainder of the duct having this coat developed to an intermediate extent. Beneath the middle coat is the mucous lining, the cylindrical epithelium of which commences, according to Henle, suddenly at the excretory orifice, and continues as far as the delicate divisions of the duct in the substance of the gland. The cells of this epithelium in the main duct range from the -0V0 to the part of an inch in their long diameter.\nThe parotid derives its arterial supply from the main trunk of the external carotid, the supei ficial temporal, transverse facial, anterior and posterior auricular : its venous, from vessels of the same name. The lymphatics terminate in the superficial and deep facial and cervical glands. The nerves are derived from the facial, the anterior auricular, and the external carotid plexus.\nThe Submaxillary gland, much smaller than the parotid and larger than the sublingual, is situated in the anterior portion of the digastric space. It is irregularly oblong in form, and is enclosed in a loose investment of areolar tissue more delicate than that covering the parotid. Its long axis is directed from before backwards, and is about an inch and a half in extent. Its external or maxillary surface is slightly concave, is lodged in a groove in the bone, and is in immediate contact with the mylo-hyoid nerve. The inferior or platysmal surface is in relation with the platysma-myoides and superficial cervical fascia, constituting, in fact, that part of the gland which is seen on reflecting that muscle. The internal surface, which looks slightly upwards, is in relation with the posterior third of the mylo-hyoid muscle, the tendon of the digastric, and the stylo-hyoid and stylo-glossus. The anterior extremity, which is smaller than the posterior, impinges on the anterior belly of the digastric. The posterior border is deeply grooved by the facial artery and vein, which are occasionally surrounded entirely by the structure of the gland. From the narrowest portion of the gland,\nwdiich would be represented by the confluence of the inner and outer surfaces above, generally proceeds a process, longer than the gland itself, and passing along the upper surface of the mylo-hyoid muscle in company with the excretory duct, but above it, as far as the sublingual gland in front, with which it is occasionally incorporated. This process may be regarded as analogous to the accessory gland of the parotid, and like it varies considerably in size and relation to the body of the gland. In a subject recently examined, we found it represented by two accessory glands, the upper or larger being about the size of a horse-bean, embracing the posterior half of the lower border of the sublingual gland, and grooved behind by the trunk of the gustatory nerve. It opened by a distinct duct, more than half an inch in length, into the main canal about the middle of its upper border : the other accessory gland, very small, situate half an inch further back, and also communicating with the lower border of the main duct by a canal one-sixth of an inch long. The primary lobes of the submaxillary gland are much larger than those of the parotid, and the lobules have an irregularly triangular arrangement.\nA quarter of an inch below the part at which the accessory process is ordinarily given off, appears the commencement of the excretory canal, or Wharton\u2019s duct, winding behind the posterior border of the mylo-hyoid muscle. It first lies below the gustatory nerve between it and the lingual, and after a course of a quarter of an inch, crosses the former at an acute angle, and again gets below it, resting on the hyo-glossus muscle. It accompanies the gustatory towards the tip of the tongue between the sublingual gland and the genio-hyo-glossus muscle to the side of the fr\u00e6num linguae, where it terminates. In the terminal part of its course it is directed forward, lies immediately beneath the mucous membrane, and opens by a very narrow orifice into the mouth, in the centre of a papilla of mucous membrane. This papilla forms an obvious prominence by the side of the fr\u00e6num linguae, and is situated above the eminence formed by the anterior part of the upper edge of the sublingual gland, behind the incisor teeth. The duct is about two inches in length, its coats much more delicate, and consequently more extensible, than those of the parotid. Its calibre exceeds that of the parotid duct, and, like it, its narrowest portion is that immediately beneath the mucous membrane, and this gradually contracts more and more, so that the terminal orifice becomes so small as scarcely to be visible by the naked eye. The arteries and veins that supply the submaxillary gland, are derived from the facial and lingual. The nerves are from the mylo-hyoid branch of the dental, and the gustatory, but chiefly from the submaxillary ganglion. The lymphatics communicate with the deep cervical glands.\nThe Sublingual gland forms a distinct eminence underneath the anterior part of the tongue by the side of the fr\u00e6num. It","page":424},{"file":"p0425.txt","language":"en","ocr_en":"SALIVARY GLANDS.\n425\ncan be felt in the floor of the mouth, and forms a prominent ridge which elevates the mucous membrane. Its long axis is from before backwards, following, in fact, the direction of the horizontal ramus of the jaw, to which the gland is applied. The inferior surface rests upon the mylo-hyoid muscle; the external is received into the sublingual fossa ; the internal is in relation with the genio-hyo-glossus and hyo-glossus below, and the mucous membrane above, the upper edge being covered by the latter. It is shaped somewhat like an almond, flattened from side to side, having its large extremity anteriorly. It is more compact in front than behind, in which latter situation its component lobes are occasionally separated the one from the other, and exist under the form of distinct irregularly rounded glands, with separate excretory ducts about a quarter of an inch in length, coming from their upper surface. The sublingual gland is from one inch and a half to two inches in its long axis, three quarters of an inch in the longest part of its vertical diameter, and about a quarter of an inch from side to side. It has a more granular feel, and its lobules, which are mutually connected by a very delicate areolar tissue, are more distinct, harder, and smaller than in either the submaxillary or parotid.\nThe ducts of the sublingual are very numerous, and their orifices can be seen without much difficulty, opening into the floor of the mouth, behind the movable papilla of Wharton\u2019s duct, and along the crest of mucous membrane which is elevated by the upper border of the gland from which they take their origin. They are extremely thin and delicate, and pour out, when pressure is made on the body of the gland, a distinctly viscid saliva. They range from one-tenth to one-third of an inch in length, vary much in their direction and relative situation, and are in number from 7 to 15. The anterior are very short, curve slightly on themselves from behind forwards, are about four or five in number, and some of them, according to many anatomists, form a communication with Wharton\u2019s duct, the remainder piercing the mucous membrane of the mouth. The ducts from the middle and posterior part of the gland arise at unequal intervals from each other, run in a parallel, divergent, or convergent direction, and pierce the mucous membrane by straight orifices, the posterior two or three not being longer than the one-tenth or one-eighth of an inch. They are known under the name of the Ducts of Rivinus. Bartholinus* has described another duct in connection with the sublingual gland, and which sometimes proceeds from the accessory gland of the submaxillary. It runs parallel to Wharton\u2019s duct, and pierces the mucous membrane by the side of it. It frequently opens, however, into Wharton\u2019s duct, and both terminate by a common mouth. It is by no means\n* Caspar. Bartholin. Thom. fil. deductu Salivali hactenus non descripto Observatio Anatomic a. 1684.\nusually met with. In a young male, whose salivary glands we recently dissected, the duct of Bartholinus was very distinct (a a, fig. 139).\nFig. 304.\na a, the ducts of Bartholinus; bb, the ducts of Wharton; cc, the inner surface of the sublingual gland ; d, inferior surface of the tongue.\nIt arose from a large lobe at the upper third of the internal surface of the sublingual gland, midway between its anterior and posterior extremity. It was nearly equal in calibre to the duct of Wharton, and was more than half an inch in length, and opened on the left side close to the orifice of that duct in the centre of the loose papilla of mucous membrane. The two orifices were so closely approximated that it was difficult to determine their individual identity. The duct of Bartholinus of the right sublingual, on the other hand, although arising from the corresponding part of the body of the gland, and being of the same length and calibre, opened at the anterior part of the crest of the mucous membrane, the one-eighth of an inch behind the orifice of Wharton\u2019s duct.\nThe sublingual gland derives its arterial supply from the sublingual branch of the lingual, and the submental. Its nerves are derived from the gustatory branch of the fifth. Its lymphatics communicate with the deep cervical glands.\nThe salivary glands, according to the researches of Huschke, are more voluminous, in proportion to the bulk of the body, in the infant than the adult, the submaxillary and sublingual, however, being proportionately larger than the parotid. In the adult, on the other hand, the parotid is, in proportion to the bulk of the body, larger than the other two.\nThe subsidiary salivary glands. \u2014 The labial, buccal, molar, palatine, posterior, and interior lingual glands may without any impropriety be reckoned among the glands of the salivary apparatus, being identical in their structure, and provided with excretory ducts opening on to the free surface of the mucous membrane. Varying materially in size, and irregularly rounded or flattened, they exude a","page":425},{"file":"p0426.txt","language":"en","ocr_en":"426\tSALIVARY\nslightly viscid saliva by their orifices, which are visible to the unassisted eye.\nWe have already stated that the posterior part of the sublingual gland is occasionally represented by one or more distinct glands in juxta-position, each furnished with a very short excretory duct. These distinct lobes of the gland are in every way analogous to one of the molar glands or larger labial. It will thus be observed that the transition of the primary to the subsidiary glands is by no means rapid, but that they run the one into the other by insensible gradations, the sublingual gland passing from the one series into the other. A molar, labial, or buccal gland, with its excretory duct, might then be not inaptly compared, according to its size, to a secondary or tertiary lobule of the parotid, or submaxillary.\nThe labial glands form a series of closely packed small spheroidal glands, of considerable density, situated in the areolar tissue between the mucous membrane of the mouth and the orbicularis oris muscle, and in relation above and below, consequently, with the upper and lower lip. They are not of uniform volume or number. Sebastian * has observed as many as fifty-seven in the lower lip, and in other instances from thirteen to twenty-one, their size increasing in the inverse ratio to their number. They are more numerous in the infant than in the adult. Their excretory ducts open perpendicularly or obliquely into the vestibule of the mouth on the posterior or free surface of the labial mucous membrane. They are not visible to the eye when the lips are in their natural lax position, but when the latter are everted, so that the mucous membrane is rendered tense, they form considerable projections.\nThe buccal glands are exactly analogous to the labial glands in form and position, being irregularly spheroidal, and placed between the buccinator and mucous membrane, and open by the orifices of distinct ducts on to the free surface of the latter. They are, however, smaller.\nThe molar glands\u2014two, three, or four in number \u2014 form an exception as regards their situation to the above glands, being placed between the buccinator and masseter muscles. They are also larger and more dense, being composed of several lobes. The ducts terminate by opening on to the mucous membrane at the posterior part of the cheek. In a subject we recently examined, their terminal orifices were arranged horizontally at unequal distances from each other, on a level with the orifice of Steno\u2019s duct, but more than half an inch behind it. They were five in number. We have not succeeded in observing the communications which the ducts of one or more of these glands is stated by some anatomists to establish with the duct of the parotid.\nThe palatine glands are very numerous and\n* Sebastian, Kecherches sur les Glandes Labiales, Annales de la Chirurgie. Paris, 1842. t. vi.\nGLANDS.\nsmall, and situated partly between the mucous membrane and the palatine arch, and partly between the mucous and muscular layers of the soft palate. The former are situated on either side of the median line, and form a thick layer, being more closely aggregated together in the front and behind than in the middle, opening on to the mucous membrane by distinct orifices. The latter, smaller than the former, exist both on the upper and lower surface of the velum, and are continuous below, where they are more numerous than above, with the glands of the hard palate.\nThe posterior lingual glands are placed at the back part of the tongue, directly behind the large papillae, which form a distinct prominence at this part. They are spheroidal, and have remarkably short excretory ducts, the circular orifices of which, however, are distinctly visible.\nThe last glands to which we would direct attention are two in number, and from their situation may be appropriately termed the anterior lingual glands. They have been recently described by Blandin, Nuhn*, and Schlemm, as being situate below the apex of the tongue, between the lower longitudinal and transverse muscular fibres, and pouring their secretion during the movements of that organ on to the mucous membrane beneath the tip. They have only as yet been discovered in man and the ouran-outan. We have observed them on the inferior surface of the tongue, half an inch behind its anterior border, immediately above the longitudinal muscular fibres, one on either side of the median line, and about two-thirds of an inch long. Broad behind and narrow in front, they are separated from each other in the former direction by an interval of about half an inch, in the latter are almost in mutual contact. Their direction therefore is obliquely from behind forwards and inwards (Jig. 305, b). Each gland is fur-\nFig. 305.\na. Bristles in the orifices of the ducts of the left anterior lingual gland, b. The right anterior lingual gland, c. The raphe of the tongue.\nnished with three or four delicate ducts, given off from its lower surface, and which perforate the mucous membrane obliquely parallel to the long axis of the gland (fig. 305, a). These glands are of less consistence than the molar or labial. We have met with one instance in\n* A. Nuhn, \u00fcber eine bis jetzt noch nicht n\u00e4her beschriebene Dr\u00fcse im Innern der Zungenspitze. Mannheim, 1845, quoted by Valentin in Physiologie der Menschen, 1847, zweite Auflage.","page":426},{"file":"p0427.txt","language":"en","ocr_en":"SALIVARY\nwhich only one gland was present, running at right angles to the middle line. It was convex in front and concave behind, having a transverse diameter of one-third of an inch, an antero-posterior one-eighth of an inch. It gave off three delicate ducts.\nThe minute structure of the glands in general has been already fully inquired into *, and to the type on which they are formed the salivary glands offer no exception. A simple caecal membranous prolongation is the model to which they can all be referred, however complex each individual series of glands may appear. This grand generalisation, by which the extreme simplicity of the operations of nature is remarkably illustrated, has mainly been the result of a minute inquiry into developmental and comparative anatomy. We are particularly indebted, however, to M\u00fcller and E. H. Weber for the exposition of the evolution and minute structure of the salivary glands.\nMuller thus describes the first appearance of a salivary gland in Mammalia, and his observations were taken from the embryo of a sheep, two inches long : \u2014 Its form is that of a simple canal with bud-like processes, lying in a gelatinous nidus or blastema, and communicating with the cavity of the mouth. As the development of the gland advances, the canal becomes more and more ramified, increasing at the expense of the germinal mass or \u201c blastema,\u201d in which it is still enclosed. The blastema soon acquires a lobulated form, corresponding to that of the future gland, and is at last wholly absorbed. Valentinf remarks that a portion of this blastema, which contains nuclei and cell-formations, and which is not converted into glandular structure, is changed into blood-vessels, nerves, and connecting cellular tissue; and he has, further, accurately determined that the secondary tubes are formed independent of the primary, at the expense of portions of the blastema, in the vicinity of the main duct, with which, by a centripetal development, they ultimately communicate. Thus, in the first stage of their development, the salivary ducts can be seen to constitute an independent closed system of tubes. The investigations of E. Weber | carry us a step further in the inquiry. He found, by a successful injection of the parotid in a human foetus, that the excretory duct, after having undergone its ultimate state of subdivision, by an extensive ramification of its secondary tubes, terminated in microscopic twigs, each twig having appended to it one or more minute cells or vesicles, forming small group-like lobules or bunches. These cells have not a uniform size, their long diameter, which is more or less in a line with the axis of each of the terminal divisions of the duct with which the cells are structurally continuous, is, on the average, almost T-i^- of a\n* Yide Article Gland.\nf Wagner\u2019s Handw\u00f6rterbuch der Physiologie, Article Gewebe.\nJ Meckel\u2019s Archiv, f\u00fcr Anatomie et Physiologie, 1827.\nGLANDS.\t427\nParis line. Gerber * states these vesicles or cells are variously shaped, from to of a Paris line in diameter, and upon the periphery of the gland appear mutually to compress each other and to become polyhedral in their outline. They are united together into small lobules, from four to seven times greater than each individual vesicle, the latter consequently being almost three times, the former about twelve times the diameter of the capillary blood-vessels which ramify on the surface. They form, in fact, the caecal terminations of the branches of the excretory tubes, without having of necessity an individual narrow connecting pedicle, as figured by Berresf in the minute anatomy of the parotid.\nSuch, then, is the essential structure of the salivary glands ; and in the full state of organisation of each we recognise the elements of a mucous membrane, constituting the internal lining of the excretory duct and continuing throughout the series of its ultimate ramifications as far as the terminal vesicles ; a middle elastic coat, and an external covering of areolar tissue. The mucous membrane consists of an epithelial layer, and a basement membrane. The epithelium is of the columnar variety, and maintains this character along the track of the excretory duct as far as its delicate divisions, where it gradually changes its character, so that that lining the interior of the vesicles is of the pavement type. This transition of columnar into pavement epithelium would appear gradual; so that it is difficult to determine the point at which the one form terminates and the other commences. The basement membrane is continued along the entire track of the tubular ramifications, as far as the vesicles, the form of which it would appear to determine. There can be little doubt that this is the membrane which Berres alludes to as the proper wall of the vesicles, and describes as a small transparent membrane, covered over with molecules, and which also has been represented by Henle as homogeneous, but which he at the same time considers as composed of filaments of cellular tissue solidly united together.^:\nConsiderable difference of opinion has existed as to the nature of the middle coat of the glandular tubes, according as the largest or smallest have been examined. Valentin remarks that in the first case it has been considered fibrous, in the second simply homogeneous. In by far the greater number of the terminal extremities of the glandular tubes the intermediate membrane appears clear and transparent, and gives neither in the fresh state, nor when reagents are applied, any indication of a fibrous character. Inallthelarge tubes the intermediate coat is formed of distinct flat fibres, together with the characteristic fibres of cellular tissue,\n* Gerber, General and Minute Anatomy of Man and the Mammalia, translated by E. Gulliver, 1842.\nj- Anatomia Microscopica Corporis Humani, tab. ix. fig. 2.\nX M\u00fcller\u2019s Archiv. 1838, p. 105.","page":427},{"file":"p0428.txt","language":"en","ocr_en":"428\tSALIVARY GLANDS.\nstudded at intervals with elongated or rounded nuclei, which present a great analogy with the fibres of organic muscle, if they be not completely identical with it. We are at present, however, in doubt as to whether the intermediate membrane of small glands, and of the terminal portion of the large, be really a simple transparent membrane, or whether it acquire, as the tubes which it envelopes enlarge, cellular and muscular fibres externally, whilst the previously transparent membrane disappears or remains as a basement membrane towards the epithelium ; or whether a separation or splitting of the transparent membrane into fibres takes place. In the opinion of Henle, all the true glands having a vesicular termination, from the smallest to the most complicated, have an intermediate muscular tunic, with a series of longitudinal fibres situated within, and circular fibres without, the former being much more highly developed than the latter, and entirely absent in the more delicate ramifications of the duct. M\u00fcller, admitting the great difficulty of determining by the microscope the muscular character of the intermediate coat, is nevertheless of opinion that such is its nature, and appears inclined to believe that the frequent sudden expulsion of the saliva is attributable to it.\nThe cellular or areolar tissue forms an intricate network throughout the whole structure of the salivary glands, and can be distinctly traced to proceed along the course of the duct and its primary, secondary, and ultimate subdivisions. It unites together, more or less firmly, the different lobes and lobules, ultimately expanding over the primary aggregations of the vesicles of the gland, where it is lost to observation, not appearing to extend between each individual vesicle. The spaces, then, between the lobes and lobules are filled up with areolar tissue, which forms a kind of rete for the ramifications of the arteries, veins, and nerves.\nThe vascular supply.\u2014This is derived from\nFig. 306.\nCapillaries of Parotid of Pig.\nsmall branches which penetrate the areolar tissue at different points of the surface, and are conducted, as it were, by this tissue through the interlobular spaces as far as the primary aggregations of the vesicles, where they form a network, which is distributed over the elementary parts of the gland, as seen in fig. 306, the vascular arrangement in the parotid of a pig, from a preparation of Mr. Quekett\u2019s, and in which the capillary vessels range from the to \u00b0f an ^nc^*\nThe nervous supply. \u2014 The nerves are derived partly from the cerebro-spinal, and partly from the sympathetic system, and form a plexus around the arteries, which is ultimately lost in the interior of the gland. Their exact distribution, however, has not yet been accurately determined.\nThe arrangement and course of the lymphatics have yet to be made the subject of investigation.\nThe salivary glands are particularly called into play during mastication: and in order clearly to understand their relative importance, it will be necessary briefly to consider the nature of that process.\nThe food having been taken into the mouth, is, in the first instance, coarsely divided by the incisor teeth ; and this division takes place by the alternate elevation and depression of the lower upon the upper jaw. This having been accomplished, the food is next submitted to the action of the molars, reaching the back part of the dentar arches, where the rotatory or grinding movement, brought about by the pterygoid muscles, is peculiarly exerted. Here its ultimate mechanical reduction and intimate admixture with the saliva from the parotid takes place in the following manner : \u2014 By the elevation of the jaw and the rotatory movement of the above muscles, it is alternately passed from between the two sets of teeth to between the latter and the cheeks on the one hand, and the tongue on the other. The buccinator contracting, urges it again between the two sets of teeth, from which it passes between them and the tongue, and is pushed, by the contraction of the muscles of that organ, again to its original position, between the dentar arches. These different movements are alternately kept up until the entire mass of food has assumed its requisite state of mechanical reduction, and during them the saliva flows down from the orifice of Steno\u2019s duct, becoming intimately incorporated with it, and aiding most materially in its integral subdivision.\nIt is worthy of remark, that the position of the terminal portion of Steno\u2019s duct, or rather that part of it which passes between the fibres of the buccinator muscle, is such that it must be pressed upon during the contraction of the muscle at that particular time when by the same action the food would be placed between the two sets of molar teeth, and the saliva not be immediately required. During the relaxation of the buccinator, on the contrary, and when the food","page":428},{"file":"p0429.txt","language":"en","ocr_en":"SALIVARY GLANDS.\n4 29\nwould be situated between the cheek and the teeth, the quantity of saliva amassed in the canal of the duct, by its temporary obliteration, would flow down and become intimately mixed up with the particles of the food, which would now entirely surround its orifice. This relation, then, of the buccinator with the duct of the parotid would seem to regulate the supply of saliva, which, if this view be correct, flows down only at a time when it can be most thoroughly incorporated with the material during its mastication. The relation of the ducts of the submaxillary and sublingual glands to this process would seem to be of far less importance. The orifices of Wharton\u2019s ducts and the sublingual ducts situated behind the incisor teeth, would appear to hold a direct relation only to the primary stage of mastication, that is to say, lubricating with the saliva the larger masses into which the food is broken up during that process, and probably after its completion, immediately prior to the passage of the whole mass into the stomach.\nThe position, then, of the duct of the parotid, which is so situated that mechanical means are brought into play, in order to insure the thorough incorporation of its saliva with the food, and the great comparative size of the gland itself, lead naturally to the inference that the parotid is by far the most important gland in the series, the submaxillary and lingual having but a subordinate function. This deduction has been experimentally proved by Bernard*, who, having made an aperture at the lower part of the oesophagus of a horse, administered to the animal about sixteen ounces of oats. Fifteen or sixteen seconds after the commencement of mastication, a rounded mass made its appearance at the oesophageal opening, well triturated, perfectly moist, pasty in the interior, and covered on the exterior by a moderately thick layer of tenacious mucus and saliva. A fresh quantity of the oats, in a similar condition, was projected every three-quarters of a minute. At the end of nine minutes, the mastication of the entire quantity having been finished, the ducts of the parotid were divided, so that the saliva that was secreted could be conducted out of the mouth. The same quantity of oats was again given to the animal. In this second experiment mastication did not appear to be attended with any particular inconvenience, and was performed as easily as in the first. It was exerted, however, a much longer time ; for a minute and a half elapsed before the first mass made its appearance at the opening : this, though well triturated, and covered on its external surface with much mucus, was considerably smaller than those masses which had escaped from the oesophageal opening prior to the division of the ducts of the parotid. The interior of the mass, also, instead of being, like them, well moistened and pasty, had but slight tenacity, and\n* M\u00e9moires sur le R\u00f4le de la Salive dans les Ph\u00e9nom\u00e8nes de la Digestion. Archives G\u00e9n\u00e9rales de M\u00e9dicine, Janvier, 1847.\nwas comparatively dry. Mastication and deglutition now became more and more difficult, lengthened, and laborious, so that an interval of from two minutes and a half to three minutes frequently occurred between the exit from the oesophagus of the successive masses. The horse, in its endeavours to swallow the oats which appeared to adhere to the palate, frequently gulped down a quantity of air, which escaped with noise from the oesophagus prior to the exit of the oats that had with such difficulty passed into the canal. At the end of twenty-five minutes, but little more than eleven ounces of the oats had been masticated and swallowed, whereas, prior to the division of the parotid ducts, sixteen ounces had been well triturated and swallowed in nine minutes. Bernard further remarks, that he collected during the second experiment the saliva that flowed from the parotid ducts, and he found that it came away in an almost continued current ; but that during the time that he administered water to the animal not a single drop of saliva escaped. The circumstance of the smallness of the masses passed in the second experiment, and the dryness of their interior, taken together with their exterior envelope of tenacious mucus and saliva, which was as abundant as before the division of Steno\u2019s ducts, lead to the inference that the former condition was owing to the absence of the aqueous secretion of the parotid; the latter condition, to the fact of the submaxillary and sublingual glands being mainly engaged in the secretion of a tenacious saliva. Further experiments bring about the conclusion that the fluid from the parotid on the one hand, and from the submaxillary and sublingual on the other, are regulated by conditions special to each. Thus, the quantity of saliva secreted by the parotid of a horse is in direct ratio to the dryness of the food and the difficulty experienced in its mechanical division. The mastication of straw and hay causes the flow of more than that of oats and farinaceous matters ; the mastication of moist forms of food, hardly any. This, however, is by no means the case with the saliva from* the sublingual and the submaxillary ducts. This always flows nearly in equal abundance whether mastication be exerted on dry or moist forms of food, and, owing to its comparative tenacity, is not easily imbibed into the centre of the masticated material, but gathers round the surface of the mass, thus favouring its passage along the alimentary canal. In a mechanical point of view, then, there are two forms of saliva : the one clear and aqueous, secreted from the parotid, and which may be denominated the \u201csaliva of mastication,\u201d because its secretion is directly related to this act ; the other tenacious and secreted by the submaxillary and sublingual, \u201c the saliva of deglutition,\u201d because it always lubricates the surface of the alimentary mass, whether it be submitted to mastication or not. The above views of Bernard are materially strengthened by the fact of the high development of the parotid in animals that masticate,","page":429},{"file":"p0430.txt","language":"en","ocr_en":"430\nSALIVARY GLANDS.\nand its absence or mere rudimentary condition in those that swallow without masticating. Its comparative smallness, in relation to the submaxillary and sublingual in the human infant, is also corroborative.\nWithout entering into the physiology of the secretion of the saliva, which will be found treated of elsewhere (see Saliva, Secretion), it may be interesting to remark, that the salivary glands, although immediately surrounded by muscles, are not necessarily compressed in the different movements of the jaw. This conclusion has been arrived at by a series of interesting experiments and inductions due to Bordeu, but into the analysis of which it would be beyond the limits of this article to enter.*\nMorbid Anatomy. \u2014 The parotid gland is far more frequently the subject of disease than either the submaxillary or sublingual. The idiopathic inflammation of these glands is known under the name of Cynanche parotidea, vulgarly translated \u201c mumps.\u201d The submaxillary is occasionally, and the sublingual but rarely implicated. The surrounding soft parts, particularly the lymphatic glands, participate in the inflammation, tending greatly to increase the swelling. On account of the intimate relation of the glands with the jaw, considerable pain and inconvenience form a prominent symptom. The saliva is at first increased, and subsequently diminished in quantity. Suppuration very rarely occurs. Secondary inflammation takes place as an occasional complication of the different forms of fever. In eighteen cases of typhoid Louis observed one in which the parotid was implicated. The man died on the thirty-ninth day of the attack ; and nine days prior to death pain supervened in the parotid glands, which were found after death to be twice their ordinary volume, and studded throughout with small purulent deposits.\nThe chief point of interest, however, to the surgeon and anatomist, in connection with inflammation of the parotid, is the formation of abscess in the region of the gland. This may either take place in the subcutaneous cellular tissue superficial to the parotid fascia, or in the substance of the gland beneath that fascia. It generally occurs, in the one form or the other, in connection with phlegmonous erysipelas of the face and neck. Abscesses forming in the latter situation demand the prompt attention of the surgeon, inasmuch as they are attended with the most severe constitutional symptoms, which are only relieved by a free incision through the dense fibrous envelope of the gland : unless thus treated, the matter either makes its way through the external auditory canal, by passing between its bony and cartilaginous divisions, or, after the most severe symptoms, bursts externally in the parotid region. It may even extend deeply into the neck as far as the trachea, and terminate by effusion into the chest and\n* Bordeu, Recherches Anatomiques sur la Position des Glandes, et sur leur Action. Paris, An. viii.\n\u2014 death. Independent of this extensive burrowing, matter pent up beneath the parotid fascia may exert a most injurious influence by compression of the larger vessels of the neck, the structure of the gland itself, and the facial nerve. Examples, in fact, are on record of almost complete destruction of the gland itself, and incurable facial paralysis, from neglect of incising the parotid fascia at an early period of the formation of pus beneath it.\nIn inflammation of the salivary glands, whether primary or secondary, the areolar tissue of the gland is most usually affected ; in a few instances, however, the true structure of the gland is implicated. Berard * relates a remarkable instance of this kind, in which both the areolar and glandular tissue were affected. When the parotid was pressed, pus flowed into the mouth from Steno\u2019s duct.\nAbscesses connected with disease of the ear now and then make their way into the substance of the parotid gland.\nEncysted tumours are occasionally observed in the body of the parotid, and in all probability are more in connection with the lymphatic glands than the gland itself, except in those cases where they arise from isolated collections of saliva, owing to obstruction in some part of the excretory canal. The latter formations are, however, but rarely met with, and, when so, occur usually in the track of Steno\u2019s duct.\nThe parotid and submaxillary undergo also fibrous and carcinomatous degeneration. The latter affection, as a purely idiopathic change, is extremely rare ; and, although the records of surgery afford ample illustration of such in the parotid, according to the assertions of the authors of individual cases, the evidence in some must be received with considerable reserve. Carcinoma originating in the lymphatic glands, superficially to or beneath the parotid fascia, or, lastly, in the parenchyma of the gland itself, has been, in fact, indiscriminately described as carcinoma of the parotid gland. This subject has been minutely inquired into by Berard, as also the extirpation of the gland f in a great number of the cases on record. He concludes his observations, by remarking that scirrhus of the parotid generally calls for the extirpation of the parts affected ; and supports this conclusion by observing, that relapses after the operation are comparatively rare. This inference is at variance with the opinion of many practical surgeons ; and it would require a much more extensive and impartial series of statistics than we at present possess to arrive at a definite conclusion on the subject. No greater difficulty exists than to obtain the subsequent history of apparently successful cases in surgery, and that of those in which the parotid has been extirpated forms no exception to the remark. In the case related by Mr. Luke J ^\n* Berard, Maladies de la Glande Parotide, et de la R\u00e9gion Parotidienne. 8vo. Paris, 1841.\nt Loc. cit.\n% London Medical Gazette, Feb. 5, 1831.","page":430},{"file":"p0431.txt","language":"en","ocr_en":"SALIVARY GLANDS.\n431\nand in which there is every thing to show that the parotid was entirely extirpated, the disease returned at the end of a year, and terminated fatally. In Mr. Solly\u2019s case* * * \u00a7, in which the ascending ramus of the jaw was removed, in order to extirpate the gland as completely as possible, the disease, instead of being confined to the parotid gland, was found, a few months afterwards, by the death of the patient, to have proceeded from the brain. Other cases, again, have been described as carcinomatous affections of the parotid, but in which their details by no means indicate that such was their nature. The case related by Larrey, for example, and which he considered to be one of carcinoma, will appear, we think, on a careful perusal, to have been nothing more than a strumous affection of the lymphatic in the substance of the gland, or possibly of the gland itself, \u201cwhich had degenerated into a dense yellow lardaceous substance.\u201d-]'\nA remarkable case of hypertrophy of the parotid is related by Tenon. J It had the form of a tumour, of the size of the fist, extending from the ear to the angle of the lips ; it was soft, white, indolent and movable, some large vessels here and there ramifying on the surface. The arteries, on the death of the child, were found considerably enlarged, which circumstance, in all probability, accounted for the condition of the gland.\nBerard also met with a similar case in a child three years old. The tumour was of almost the same volume, but simulated an erectile tumour. The veins were found very much enlarged and the arteries normal, the cellular tissue reddish and granular, and the true tissue of the gland remarkably hypertrophied.\nSalivary fistulce occur in the course of the excretory duct of the parotid, in it or its smaller ramifications, and arise from accidental injury, the result of inflammation, or from ulceration of a salivary tumour, which has gradually enlarged in consequence either of inflammatory obstruction at some part of the duct, or the presence of calculi.\nMarti relates the case of a congenital deformity of the parotid duct (simulating fistula) in an otherwise healthy female infant.\u00a7 The orifice opened on the exterior of the right cheek, down which the saliva flowed.\nThe exact nature of ranula has not been clearly determined. It consists of a sublingual tumour, varying considerably in size and density. Some consider it as a mere dilatation of the duct from obstruction at its orifice ; others as a submucous tumour, external to the duct, causing its compression ; and others, again, as an encysted tumour developed in its interior. Although the analysis of the contained fluid (see Saliva) would appear to\n* London Medical Gazette, Dec. 19, 1845, and July 14, 1848.\nf M\u00e9moire de l\u2019Extirpation des Glandes Salivaires.\nx Histoire de l\u2019Academie des Sciences pour l\u2019ann\u00e9e 1760, quoted by Murat.\n\u00a7 Marti, De Loco pr\u00e6ternaturali Orificii Ductus Salivalis Stenoniani sanato. 1746.\nindicate that the last opinion were correct, it is by no means certain whether mere obstruction at the orifice of the duct may not give rise to a similar change in the quality of the saliva.\nThe morbid condition of the labial glands has been made the subject of distinct inquiry by Sebastian*, who arranges their affections under the heads of\u2014 1. Obstruction of the excretory duct. 2. Atrophy. 3. Tumefaction with hyper\u00e6mia. 4. Ulceration.\nThe first affection occurs under two forms : The one as a transparent painless tumour of a bluish tint, resembling a vesicle or hydatid in the substance of the lip, of the size of a pea, and containing a transparent viscid fluid. He has only met with it in the lower lip, on the right side, near the angle of the mouth, and always solitary, and of quick formation. The other form is comparatively frequent, and appears as small round elastic, more or less transparent indolent tumours, frequently as many as fifteen in the lower lip. The}*-exude on puncture a thick, viscid, greasy matter. The second affection is distinctly remarked in the incipient stage of cancer of the lip, which, according to his opinion, commences in the cellular tissue. The third occurs in follicular duodenitis ; and typhoid fever, as observed by him in children. He has frequently met with the fourth affection in phthisical individuals, &c.\nComparative Anatomy. \u2014 The first appearance of a salivary apparatus has been observed by Owen, in a genus of Entozoa found in the stomach of the tiger, and named by him Gnathostoma. It consists of four elongated straight blind tubes, each about two lines in length, placed at equal distances around the commencement of the alimentary canal, having their small extremities directed forward, and opening into the mouth.-]'\nAmong the Echinodermata the salivary organs in Holothuria regalis are represented by elongated c\u00e6cal processes, surrounding the oesophagus, and continued into the branched tentacles around the mouth. They exude a viscid secretion, which assists in entangling the objects which constitute the food of the animal, lubricating them, and adapting them for deglutition.\nIn Myriapoda the salivary glands consist of small transparent vesicles, constituting in Julus terrestris, for example, a clavate mass, the small extremity of which terminates in a twisted excretory canal opening into the pharynx. They are large and very vascular in the Scolopendrid\u00e6.\nIn the Insecta the salivary glands evacuate themselves either into the mouth, or the commencement of the intestine in front of the stomach.\nThey are arranged by Burmeister as follows I : \u2014\n* Loc. cit.\nf Proceedings of the Zoological Society, 1836. p. 125.\nX Burmeister\u2019s Manual of Entomology, translated from the German by W. E. Schuckard, p. 144.","page":431},{"file":"p0432.txt","language":"en","ocr_en":"432\tSALIVARY GLANDS.\nA.\tSalivary vessels opening into the mouth, generally beneath the tongue, and more seldom at the base of the mandibles. They take the following forms : \u2014\n1.\tSimple, long, undivided, twisted tubes : thus in the majority of insects, viz. all butterflies, many beetles and flies.\n2.\tAs a narrow vessel which empties itself into one or two bladders, whence the salivary duct originates (Nepa, Cimex, Sarcophaga).\n3.\tAs a ramose vessel with blind branches (Biaps).\n4.\tAs two long cylindrical pipes, which unite into one excretory duct.\n5.\tAs four small round bladders, each pair of which has a common duct (Pulex, Lygoeus, Cimex).\n6.\tAs a multitude of such vesicles in Nepa.\n7.\tAs capitate tubes, in the free ends of which many very fine vessels empty themselves (Tabanus).\n8.\tAs tubes which at intervals are surrounded by twirling blind bags (Cicada).\n9.\tAs granulated glands which on each side unite into a salivary duct, both of which join into a single evacuating duct (Gryllus).\nB.\tSalivary glands w'hich empty themselves into the commencement of the stomach, as short or long bags, either simple or furnished with processes (Bu-prestis) ; other forms as well as those just cited, are found among the Diptera : \u2014\n1.\tAs two capitate tubes, into the free ends of which many delicate vessels open (Hemerobius perla).\n2.\tAs two short processes of the same width as the stomach (Leptis and Acheta).\n3.\tAs two bags covered entirely with short blind processes (Bombylius, Bu-prestis).\n4.\tAs triangular processes, each edge of which is occupied by a row of vesicles (Chrysotoxum).\n5.\tAs six narrow tubes which surround the commencement of the stomach (Gryllus).\n6.\tThe blind processes which clothe the stomach in the predaceous beetles.\nTn Cirrhopoda the salivary glands are two in number and of considerable size, opening into the commencement of a short cesopha-gus.\nAmong Pteropoda they are found in Clio as two long and slender glands placed at the sides of the oesophagus, and pouring their secretion into the mouth. They \u201c present in the Gasteropoda different forms and degrees of development bearing the ordinary relations to the construction of the mouth and the nature of the food. Tn the Calyptr\u00e6a they are represented by two simple elongated secreting tubes. In the whelk they present a\nconglomerate structure, and are situate at each side of the oesophagus at the base of the proboscis, along which they transmit their slender ducts to terminate on each side the anterior spines of the tongue.\u201d (Owen.) In the snail they are flattened, elongated, and irregular in form, and conglomerate in structure, diminishing in breadth as they proceed upwards to the pharynx, where their ducts terminate. In the Vaginulus an additional slender tube which lies first on the stomach, passes through the nervous collar to join the duct by which the saliva is discharged.\nThe salivary glands are present in all the Cephalopoda, with the exception of Loligo-psis. In the Onychoteuthis two glands are situated at the root of the tongue. They are in general, however, four in number, two at the root of the tongue, which give off distinct ducts which terminate at the commencement of the oesophagus ; the other pair, generally longer than the superior, is lodged in the visceral sac, on each side of the upper part of the crop. The ducts of the last form a single tube which opens in the neighbourhood of the spiny portion of the tongue.\nThe salivary glands are absent in Pisces.\nAmong reptiles in the Chelonian, Saurian, and Batrachian orders, the substance of the tongue seems principally made up of a glandular mass formed by a multitude of- little tubes united at their bases, but becoming separate towards the surface of the tongue. In the Ophidian reptiles two glandular organs placed immediately beneath the skin of the gums surround the margins of the upper and lower jaw, and pour an abundant salivary secretion into the mouth. (Rymer Jones.) In many genera the salivary apparatus is deficient. The poison glands of serpents can hardly be reckoned among the salivary organs, being destined for a special secretion, and forming the analogues to similar glands in the Arachnida.\nIn Aves the salivary glands present considerable variation in their number, position, and degree of development. In the crow the only indication of a salivary apparatus is a series of simple cone-shaped follicles, placed along the sides of the oral cavity, upon the mucous membrane of which they open by distinct orifices. In general, however, there are four pairs, two sublingual on each side beneath the tongue, two maxillary divided each into an anterior and posterior, and opening by special ducts in front of the tongue, and a gland which can be compared to the parotid. These are generally all present in the Rapaces, Pas-seres, and Gallin\u00e6 ; and appear to be absent in Sula, Carbo, and Ph\u00e6nicopterus, and but slightly developed in the Grallce and Palmipedes generally. In the goose they occupy the entire space included between the rami of the lower jaw, being closely united in the median line, and opening into the mouth on each side of this by a series of orifices. In the watercoot and Hirundo esculenta, the parotid is highly developed, in the latter the secretion serving for the preparation of","page":432},{"file":"p0433.txt","language":"en","ocr_en":"SCAPULAR REGION.\t433\nits edible nests. In the woodpecker the glandular mass is of extraordinary size, extending from the angle to the symphysis of the jaw on each side, and opening by the confluence of the two ducts into a single orifice at the apex of the mouth.\nIn Mammalia the salivary glands present considerable variation. In the Monotremata they are partially deficient : in the Echidna there appears to be no parotid ; the submaxillary, on the other hand, is highly developed, extending from the meatus auditorius along the neck, and upon the anterior part of the thorax. Its ducts terminate by numerous orifices on the membranous floor of the mouth, and pour out a secretion for the lubrification of its long and slender tongue. In the Cetacea the salivary glands are absent. In the Dugong, however, one of the herbivorous Cetacea, the parotids are highly developed. In the Ruminantia the three pairs are highly developed, particularly the parotid ; and in addition to these there is a group, apparently continuous with the molar, which mounts up along the superior maxillary bone, beneath the zygoma, to the globe of the eye, as observed in the ox, the sheep, and the horse. The excretory ducts pierce the mucous membrane near the posterior margin of the superior alveolar ridge.\nIn the armadillo, among the Edentata, the submaxillary gland has appended a reservoir or bladder, receiving the saliva by small ducts, which open into it posteriorly in a valvular manner. A single duct comes off from its anterior part, and terminates just behind the symphysis of the lower jaw. The saliva is very tenacious, the serous part being probably absorbed during its detention in the reservoir, and is expelled at the extremity of the mouth, in order to lubricate the tongue, which is by this means rendered subservient, as in the ant-eater, to the catching of insects. In the latter animal the salivary secretion takes place from two glands, situated, according to Cuvier, the one in contact below with the upper edge of the masseter, and filling up a great part of the temporal, zygomatic, and orbital fossae ; the excretory duct opening into the mouth behind the superior maxilla : the other, probably furnishing the viscid secretion that coats the tongue in front of the tendon of the masseter, behind the angle of the lips, and then running along the edge of the lower lip as far as the middle. Its canal opens externally at the commissure of the lips.\nIn the Carnivora the variations of the salivary glands are but slight. The submaxillary in them, as in the Rodentia and Ruminantia, are large. The sublingual gland is absent in the cat.\nThe writer of this article has to acknowledge his obligations to the undermentioned sources, for the preceding account of the comparative anatomy of the salivary glands: \u2014 Cuvier, Le\u00e7ons d\u2019Anatomie compar\u00e9e ; Owen\u2019s Lectures on the Invertebrata ; Rymer Jones, General Structure of the Animal Kingdom ; Wagner, Elements of Comparative Anatomy, translated by Tulk ; Kelp, De Systemate Salivali,\nTOL. IV.\nand the various articles on Comparative Anatomy in this Cyclopaedia.\nBibliography. \u2014 Nuck, Disquisitio Anatomica de Ductibus Salivalibus, 1656. Wharton, Adeno-graphia sive Glandularum totius corporis Descriptio, 1659. Haller, Disputationes Anatomic\u00e6, vol. i. p. 1, ad 92. Steno (A.), De Musculis et Glandulis Ob-servationum Specimen, &c., 1664 ; Observationes Anatomic\u00e6 quibus varia Oris Oculorum et Narium Vasa describuntur, novique Saliv\u00e6 et Muci Fontes deteguntur, &c., 1662. Vater, Novi Ductus Sali-valis in Lingua Excretorii Demonstratio, 1723. Siebold ( J. Barth), Diss. Inaug. Med. sistens Historian! Systematis Salivalis Physiologice et Pa-thologice consid., &c. Jen\u00e6, 1787. Murat, Sur la Glande Parotide consid\u00e9r\u00e9e sous ses Rapports Anatomiques, Physiologiques, et Pathologiques, 1803. Millier, De Glandularum Secementium Struct. Pe-nitior, 1830. Bordeu, Recherches Anatomiques sur la Position des Glandes, et sur leur Action. Panizza (B.), Remarques Chirurgicales sur la Glande Parotide. Annales de la Chirurgie, Paris, 1844, t. x. p. 54. Vide also the Bibliography of GLAND.\n(Nathaniel Ward.)\nSCAPULAR REGION (Descriptive and Surgical Anatomy of). The term scapular region is intended by some anatomists to comprise all the structures which lie on the scapula, on its anterior as well as on its posterior surface; but, in accordance with the arrangement of Velpeau and others, we limit the term scapular region to the posterior aspect of the scapula, regarding its anterior, or subscapular, surface as appertaining to, and forming one of the boundaries of, the axillary region. Under the denomination then of scapular region, we include a portion of the posterior aspect of the shoulder, presenting a triangular outline, to which the following boundaries may be assigned. Its base, which is placed internally, is constituted by the vertebral margin of the scapula ; its apex, placed externally, becomes continuous with the region of the shoulder joint ; inferiorly, it is limited by the lower oblique edge of the la-tissimus dorsi muscle, which likewise separates it from the region of the axilla ; and above, the superior costa of the scapula constitutes its extreme boundary, and separates it from the great posterior triangle of the neck.\nBetween the integuments and the dorsum of the scapula, which forms the floor of the region under consideration, lie numerous muscles, layers of fasciae, vascular inosculations, branches of nerves, &c., which we shall describe in the order in which they present themselves in dissection.\nThe muscles, which are numerous, may be divided into the extrinsic and the intrinsic ; the latter are, the fleshy portions only of the supra- and infra-spinati, and of the teres major and the teres minor muscles. Under the former class, we shall have to speak of portions of the trapezius, latissimus dorsi, and deltoid muscles. Numerous other muscles are attached to the different borders of the scapular region ; but these have been already described in the several articles treating of the regions to which they more properly belong (vide Neck, Back, Arm). The projection backwards of the spine of the scapula naturally,\nF F","page":433},{"file":"p0434.txt","language":"en","ocr_en":"SCAPULAR REGION.\n434\ndivides the scapular region into two distinct parts, termed by anatomists the supra- and infra-spinal fossae ; and in this article we shall describe, seriatim, the anatomical relations of the structures which occupy these two fossae respectively.\nThe subcutaneous layer of areolar tissue, throughout the whole of the scapular region, is dense, and much more closely connected to the integument than to the aponeurosis beneath. Very free motion of the skin on the deeper seated structures is thus allowed. In this layer, superiorly, we find some of the superficial descending branches of the cervical plexus of nerves passing towards the region of the shoulder, where they become lost in the integument. Beneath the skin, subcutaneous areolar tissue, and superficial layer of fascia, the trapezius muscle covers all that portion of the scapular region which corresponds to the supra-spinal fossa. The fibres of this muscle take a direction downwards, outwards, and forwards, across this region, to the upper edge of the spinous process, and angle of junction between the acromion process and clavicle, into which they are inserted ; the more posterior fibres are oblique ; the anterior, coming from the superior crest on the occipital bone, descend more perpendicularly. This muscle acts powerfully as an elevator of the shoulder joint, its anterior fibres drawing the entire scapula upwards and backwards, and with it the upper extremity, whilst its posterior fibres effect the same purpose by producing a motion of rotation in the scapula, in virtue of which the posterior angle of that bone is depressed, and the anterior, or acromial extremity, proportionately elevated. In cutting through the trapezius muscle, the anatomist will probably meet with some of the terminal branches of the spinal accessory nerve distributed to this muscle ; as also descending branches of the supra-scapular artery, which, becoming superficial, maintain around the acromion process an anastomosis with the ascending (inferior acromial) branches of the acromial axis, and the circumflex branches of the axillary trunk.\nBeneath the trapezius muscle, and separating it ffom the fascia which covers the supra-spinatus muscle, a layer of fatty areolar tissue is always placed, which varies, however, in its amount, in different persons. In chronic disease of the shoulder joint, such as ulceration of the articular cartilage, and, in fact, in all cases where inflammatory action has existed in the articulation for any considerable length of time, this intermuscular fatty stratum becomes absorbed ; and to this circumstance, as also probably in some degree, to atrophy of the muscular fibres, is due the peculiar flattening, or even the depression, so constantly observed above the spine of the scapula in such cases ; appearances analogous to the flattening of the gluteal region, which is one of the most remarkable external features of \u201c morbus coxae.\u201d\nDeeper still is placed an aponeurosis of great strength, which forms, with the smooth\nconcave surface of the supra-spinal fossa, an osteo-fibrous canal, containing the fleshy portion of the supra-spinatus muscle. This fascia is stretched between the superior costa and the spine of the scapula ; by its under surface, posteriorly, it affords attachment to the fibres of the supra-spinatus ; whilst anteriorly it accompanies the tendon of that muscle, under the acromial end of the clavicle and the triangular ligament, losing itself on the capsular ligament of the shoulder joint.\nBy the removal of this fascia, we bring into view the supra-spinatus muscle, filling accurately the fossa from which it derives its name, and from nearly the entire of which it derives its origin ; anteriorly, however, the muscular fibres have no ossifie attachment. They here glide over the smooth, pulley-like surface presented by the bone, and then, bending downwards and outwards, they form the tendon of the muscle, which is inserted further on into the upper facette of the great tuberosity of the humerus, becoming also incorporated with the capsular ligament. In this part of their course the supra-spinatus muscle and tendon are concealed by the acro-mio-clavicular articulation, and more externally by the coraco-acromial, or triangular ligament, which is stretched in the form of an arch above them ; a bursa of large size intervenes between the under-surface of the ligament and the superficial, or upper aspect of the tendon. By the removal of the trapezius muscle we are also enabled to see the attachments of several muscles to the edges of the supra-spinal fossa ; thus the insertion of the levator anguli scapulae into the posterior superior angle of the scapula becomes apparent ; also the attachment of the upper fibres of the serratus magnus anticus to its superior costa; and that of the omo-hyoid muscle to \u201c the ligament of the notch,\u201d and the base of the coracoid process. In this situation also the supra-scapular nerve and artery enter the supra-spinal fossa, usually separated from one another by \u201c the ligament of the notch.\u201d The nerve, in the majority of instances, being beneath, and the artery above, the ligament, the nerve is transmitted through a foramen, formed by the notch in the upper edge of the scapula and the ligament of the notch, whilst the artery enters the fossa through a small triangular interval, the respective sides of which are constituted by the ligament of the notch, coracoid process, and the posterior belly of the omo-hyoid muscle.\nThe supra-scapular nerve is a branch from the upper division of the brachial plexus : in the neck it follows the course of the omohyoid muscle to the scapula, passes beneath the origin of that muscle and through the foramen above described ; after which it enters the supra-spinal fossa, and is distributed, firstly, to the supra-spinatus muscle ; secondly, to the infra-spinatus and teres minor muscles, by a branch which passes beneath the acromion process ; and, thirdly, by a few twigs to the exterior of the capsule of the shoulder joint.","page":434},{"file":"p0435.txt","language":"en","ocr_en":"SCAPULAR REGION.\t435\nThe suprascapular artery (sometimes designated arteria transversalis humeri) has elsewhere been described as arising from the thyroid axis of the subclavian trunk ; it passes at first downwards, and then nearly transversely outwards, anterior to the phrenic nerve, and between the sterno-cleido mastoid and the anterior scalenus muscles ; it next runs along the base of the supra-clavicular triangle in close contact with the front of the subclavian vein, behind the clavicle and subclavian muscle, and below the level of the subclavian artery, here in the third stage ; more externally it crosses this great trunk near the commencement of the axillary ; it then passes in front of the brachial plexus of nerves, running along with the supra-scapular branch, parallel to the omo-hyoid, and covered by the trapezius muscle, to the superior costa of the scapula, where it enters the supraspinal fossa above \u201c the ligament of the notch.\u201d Whilst under cover of the trapezius muscle, the supra-scapular artery gives off a large muscular branch, the ramifications of which have been alluded to as assisting to form the acromial anastomosis. The final distribution of the artery is by two branches.\n1.\tThe supraspinal branch, which is distributed to the supra-spinatus muscle, and which anastomoses near the posterior superior angle of the scapula, with branches from the posterior scapular artery.\n2.\tThe infraspinal branch, which enters the infra-spinal fossa by passing beneath the acromion process, and the \u201c spino-glenoid ligament \u201d of Sir Astley Cooper ; here it is distributed to the deep surfaces of the muscles of this region, and anastomoses freely with the termination of the posterior scapular, and with the posterior branch of the subscapular arteries.\nThe structures thus shown to be contained in the supra-spinal division of the scapular region are the following: \u2014 1. Integument, dense areolar tissue, and superficial nerves ; 2. A thin aponeurosis covering, 3. The trapezius muscle ; 4. A layer of fatty areolar tissue ; 5. The strong supra-spinal aponeurosis ; 6. The supra-spinatus muscle ; 7. The supra-scapular vessels and nerve ; 8. The smooth concave surface of the bone (fossa supra-spinata).\nBelow the spine of the scapula portions of the trapezius, deltoid, and latissimus dorsi muscles overlap the scapular region, and partly conceal from view the intrinsic muscles of the infra-spinal fossa. These muscles are covered by an aponeurotic expansion, which is thin over the trapezius and latissimus dorsi muscles ; more dense and strong where it covers that part of the deltoid which belongs to the region of the shoulder ; and much stronger still, where it invests the infra-spi-natus and teretes muscles ; superiorly, it is attached to the lower edge of the spine of the scapula ; posteriorly, it is connected with the tendinous expansion of the trapezius muscle, and the base of the scapula. From its deep surface, septa are detached, which pass in\nbetween the subjacent muscles, and contract firm adhesions to the bone ; whilst, at the posterior edge of the deltoid muscle, it divides into two lamin\u00e6, between which that muscle is enclosed ; the superficial layer covers the outer surface of the deltoid, and so becomes identified with the fascia of the arm ; whilst the deeper layer, passing beneath the deltoid muscle, becomes continuous with the capsule of the scapulo-humeral articulation.\nThe trapezius and latissimus dorsi muscles overlap\u2014the one, the posterior superior, the other, the inferior angle of the scapula. The trapezius is tendinous where it glides upwards and forwards over the smooth triangular surface situated behind the spine of the scapula. A bursa here intervenes between the bone and the flat tendinous expansion of the muscle. The latissimus dorsi, by its fleshy fibres, overlaps the inferior angle of the scapula. The direction of the muscle at this part of its course is nearly horizontal. As these fibres pass off the scapula, they are joined by those of its costal origin, and thence they all run upwards and forwards, presenting a twisted appearance to their insertion, which takes place by a narrow flat tendon into the bottom of the bicipital groove of the humerus. Both these muscles, from their peculiar relation to the scapula, serve to compress it against the thorax, and so to prevent its being unduly separated from the trunk in the varied and extensive movements which it enjoys.\nA peculiar displacement of the scapula, the result of accident, has been described by Velpeau, who supposes it to depend on paralysis of the serratus-magnus from injury of the great posterior thoracic nerve (external respiratory, Ch. Bell), which is distributed to that muscle. The appearances observed in the case detailed by Velpeau were, remarkable projection backwards of the scapula, especially of its posterior border, and inability on the part of the patient to bring it in contact with the side of the thorax : cases corresponding in their general features to this description have been seen by almost every surgeon. In those which have occurred in the writer\u2019s experience, the projection of the posterior edge and of the lower angle of the scapula was very remarkable, and the movements of the upper extremity were greatly impeded. Mr. Adams has suggested, as a more plausible explanation of the deformity in these cases, that the lower angle of the scapula escapes from under the latissimus dorsi muscle ; an accident which may occur from too great elevation and abduction of the upper extremity ; and the more easily, as, in the majority of instances, either the muscle is not attached to the bone at all, or else it adheres to it by a few small fibres only.\nThe deltoid, trapezius, and latissimus dorsi muscles, where they overlap the scapular region, circumscribe a triangular space, in which may be seen part of the posterior edge of the scapula, with the attachment to it of the rhomboid muscle, and also a portion of the infra-spinatus and of the teres minor muscles.","page":435},{"file":"p0436.txt","language":"en","ocr_en":"SCAPULAR REGION.\n436\nBy the removal of so much of these superficial muscles as encroach on the scapular region, and of the strong fascia already described, the deeper seated muscles of the infra-spinal fossa, viz. the infra-spinatus and the teres major and minor, are completely exposed.\nThe infra-spinatus muscle arises from the upper four-fifths of the dorsum of the scapula below its spine. The strong fascia of investment already described also furnishes an extensive surface of origin to its fibres ; the muscle is triangular, the fibres all converging anteriorly to their common tendon, which, passing beneath the spine of the scapula and the acromion process, approximates closely to the tendon of the supra-spinatus muscle, and is inserted immediately beneath it, into the great tuberosity of the humerus.\nThe teres minor muscle seems to be little else than a fasciculus of the last described muscle, to which it is parallel, and along the lower edge of which it is placed : anteriorly, it is inserted by a separate tendon into the lowest portion of the great tuberosity of the humerus. The teres minor and infra-spinatus muscles might be regarded as different portions of one and the same muscle, not only from the similarity of their anatomical relations, but also from the identity of their physiological functions; both draw downwards and backwards the humerus, and produce the rotation outward of the arm at the shoulder joint. The teres minor is placed between the infra-spinatus superiorly and the teres major inferiorly, in close contact with the former, from which an aponeurotic septum and branches of blood-vessels alone separate it ; whilst a very considerable space, containing the long head of the triceps, and s)me important nerves and vessels, intervenes between it and the teres major.\nThe teres major and the teres minor muscles arise close together from the lowest portion of the dorsum of the scapula. The teres major (the more superficial of the two at its origin) is attached to the rough surface on the outer aspect of the inferior angle of the scapula, whilst the teres minor arises more anteriorly, from a narrow but well-marked groove, situated just above the axillary margin of the bone. At their origin the teres minor is concealed by the teres major, but as they pass towards the humerus they gradually diverge, and are inserted on different aspects of the bone, and at different levels, so that the long head of the triceps firstly, and the neck of the humerus secondly, intervene between them. The teres minor is inserted on the outside of the humerus into its great tuberosity, below the insertion of the infraspinatus muscle, whilst the teres major, in company with the latissimus dorsi, passes on the inner aspect of the humerus, and is inserted along with it into the bottom of the bicipital groove: at their insertion, the tendon of the teres major is posterior, and a little inferior to the tendon of the latissimus dorsi.\nThe teretes muscles, in diverging to the humerus, form with the upper part of that\nbone a triangular space, of which the base is at the humerus, and the apex at the inferior angle of the scapula. The scapular origin of the triceps extensor muscle in its vertical course down the arm, crosses this space, and divides it into compartments, a posterior triangular, and an anterior quadrilateral one, through both of which the axillary cavity communicates with the posterior region of the scapula and shoulder.\nThe triangular compartment, overlapped posteriorly by the deltoid muscle, is bounded, above, by the teres minor and axillary edge of the scapula; below, by the teres major. Its base, situated externally, is formed by the long head of the triceps ; whilst its apex, directed internally, corresponds to the point of contact of the teretes muscles, where they arise together from the scapula. In this compartment is seen the posterior branch of the sub-scapular artery (circumflexus scapul\u0153, Soemmering), forming here a curve, the convexity of which is directed downwards and backwards. The artery leaves this space by bending upwards and backwards, beneath the teres minor and infra-spinatus muscles. It thus arrives in the infra-spinal fossa, lies next the bone, and ramifying minutely anastomoses, superiorly with the descending branch of the suprascapular artery, and posteriorly with the termination of the posterior scapular artery. ( Vide Axillary Artery.)\nThe quadrilateral compartment is bounded above, by the capsular ligament of the shoulder joint, by the prominence of the head of the humerus, and by the tendinous attachments of the teres minor and of the sub-scapularis muscles ; below, by the teres major and latissimus dorsi; externally, by the neck of the humerus ; whilst, internally, it is separated from the triangular compartment last described by the long head of the triceps muscle; it transmits, from within outwards, the circumflex nerve and posterior circumflex artery. This artery contributes to form the great scapular anastomosis ; some of its branches ascending in the substance of the deltoid muscle, inosculate freely with the superior acromial branches of the infra-scapular artery, whilst others pass backwards and unite in the infra-spinal fossa, with branches of the subscapular and the posterior scapular arteries. The circumflex nerve is distributed almost exclusively to the deltoid muscle ; but two collateral branches are detached from it, which are distributed in the scapular region; the first, a branch to the teres minor muscle; the second, a cutaneous filament, which escapes from beneath the posterior edge of the deltoid muscle, and is distributed to the integument.\nThe posterior scapular artery, although placed beyond the limits of the scapular region, may, nevertheless, be here described, as it is distributed chiefly to the parts contained within it. Under the name of \u201ctrans-versalis colli,\u201d this artery arises in the neck from the thyroid axis, near to, and sometimes by a common trunk with, the transversalis humeri ; it sometimes comes from the sub-","page":436},{"file":"p0437.txt","language":"en","ocr_en":"SCAPULAR REGION.\t437\nclavian, external to the scaleni muscles,\u2014an irregularity which is by no means uncommon. When derived from its more usual source, this branch runs transversely across the scalenus anticus muscle and the phrenic nerve, covered by the clavicular portion of the sterno-cleido-mastoid muscle : it then traverses the apex of the supra-clavicular triangle, lying above the level of the curve of the subclavian artery, and placed before or between the formative roots of the brachial plexus ; passing still further outwards it gets under the trapezius muscle, and here gives off its ascending cervical branch ; at the posterior superior angle of the scapula, the artery bends backwards, under cover of the levator anguli scapulae; here it changes its direction, and inclining downwards, runs along the vertebral edge of the scapula. Its course may, therefore, be divided into two stages ; the first extends from the origin of the artery to the superior angle of the scapula, and so far its direction is nearly horizontal, and it is properly designated the \u201carteria transversalis colli.\u201d In its second stage, the artery runs vertically, parallel to, and about an inch distant from, the vertebral margin of the bone. This portion of the artery, which alone should be termed \u201c posterior scapular,\u201d is covered by the greater and the lesser rhomboid muscles, and by the trapezius. To these, and to the other muscles attached to the scapula, it furnishes numerous branches, and at the inferior angle of that bone, it anastomoses very freely with the posterior branch of the sub-scapular artery.\nThe structures which occupy the infra-spinal fossa may here be briefly recapitulated : first the integument and the sub-cutaneous layer of areolar tissue ; secondly, the fleshy edges of the deltoid and the latissimus dorsi muscles, and the triangular tendinous expansion of the trapezius, covered by their respective portions of fascia: in the interval between these muscles, and partly covered by them, lie, thirdly, the infra-spinatus, the teres major, and the teres minor, muscles ; these are contained in distinct sheaths, formed by their investing fascia, and the aponeurotic septa detached from its deep surface ; fourthly, the anastomoses of branches from all the scapular arteries; fifthly, the bone (fossa infra-spinata).\nAround the margins of the scapula there exists, as has thus been shown, a chain of large blood-vessels, which, by numerous branches, anastomose freely at the angles, and on the different aspects of the bone, forming a vascular circle of great interest to the surgeon ; for by means of it the upper extremity is mainly supplied with blood, when the current through the subclavian is interrupted, at the distal side of the branches which sprihg from its first stage. At the acromial end of the scapula two series of anastomoses may be observed ; the first, superficial to the acromion process, is formed by the union of the superior acromial branches of the supra-scapular artery with the ascending (inferior acromial) branches of the circum-\nflex, and with the acromial thoracic divisions of the axillary artery.\nSecondly; an anastomosis occurs beneath the acromion process and behind the glenoid cavity, bet ween the supra- and the sub-scapular arteries.\nThirdly ; at the posterior angle of the scapula, the supra- and the posterior scapular arteries anastomose, in the posterior part of the supraspinous fossa.\nLastly ; at the inferior angle, a free communication exists under cover of the infra-spinatus muscle, between the supra-, the posterior, and the sub-scapular branches, aided by the posterior circumflex.\nThrough all these channels the sub-clavian and the axillary trunks communicate with each other, and experience has shown that full reliance may be placed on the capability of this anastomosis to maintain the circulation in the upper extremity after a ligature has been placed on the subclavian artery in the second or third stage.\nThe veins of the scapular region merit no particular description ; they are very numerous, and communicate freely with each other. They accurately follow the course of the arteries. Those which lie above the spine of the scapula form one or two trunks of considerable size, which accompany the suprascapular artery, and unite with the subclavian vein, external to the scalenus muscle; those of the infra-spinal fossa constitute a very large trunk, the sub~scapular vein, which enters the axilla and joins the axillary vein, as it lies on the posterior wall of the axilla; the sub-scapular vein here forms an important anterior relation to its accompanying artery.\nThe lymphatics of the scapular region are arranged in two sets ; the superficial which pass to the ganglia of the axilla, and a deep set which closely correspond to the course of the bloodvessels, and terminate, as do the venous trunks, in the supra-clavicular and in the axillary regions.\nThe scapular region participates in the remarkable mobility of the bone which supports it, but as its motions cannot be regarded independently of those of the shoulder joint, we refer to the article on that subject for their elucidation.\nThe uses of the scapula may be briefly stated as follows : \u2014 In the first place it connects the upper extremity to the trunk, and participates in, and is subservient to, many of the movements enjoyed by the upper extremity. Secondly, it furnishes, by its flat surface, a lateral protection to that portion of the thorax against which it is applied. Thirdly, it is concerned in the mechanism of respiration, furnishing processes and surfaces for the attachment of numerous muscles, which are capable of altering the capacity of the thorax. This latter function of the scapula is well illustrated by cases where the upper extremities are totally wanting, in which the muscles, passing from the scapula to the thorax are well-developed, and act with vigour in effecting the full expansion of the thorax.","page":437},{"file":"p0438.txt","language":"en","ocr_en":"SCROTUM.\n438\nThis fact is mentioned on Sir Charles Bell\u2019s authority, from whom we also quote the following short passage :\u2014\u201cWe would do well to remember this double office of the scapula and its muscles, that whilst it is the very foundation of the bones of the upper extremity, and never wanting in any animal that has the most remote resemblance to an arm, it is the centre and \u201cpoint d\u2019appui \u201d of the muscles of respiration, and acts, in that capacity when there are no extremities at all.\nPercussion and auscultation are constantly practised over the scapular region, the superficial position of the spine of the scapula causing it to furnish satisfactory results when percussed, whilst the nature of the respiratory sound, in the subjacent portions of the lung, may be easily learned by applying the stethoscope to the supra- or infra-spinal fossa.\nThe scapular region is sometimes the seat of furuncular inflammation, and of anthrax, which selects in general the posterior aspect of the body, where the sub-cutaneous areolar tissue is most dense, often shows a special preference for the scapular region. Here likewise practical surgeons are well aware that chronic abscesses (\u201cabsces froid \u201d) not un-frequently occur.\nCollections of matter in this situation are generally unconnected with any other local disease, but at the same time indicate constitutional derangement, more or less profound. Chronic abscess in this locality is not always superficially seated ; it may have for its site the loose areolar tissue beneath the scapula, which connects the sub-scapularis to the ser-ratus magnus muscle. Here it mav attain a great magnitude, and displace the scapula outwards to a considerable distance from the trunk.\nFractures of the body of the scapula are met with as the result of direct violence only, and occur less frequently than the slightness of the bone would lead one a priori to expect. The numerous muscles covering the bone, which form for it an elastic cushion, and its strong projecting spine, are sources of protection to which the scapula is indebted for its comparative immunity from this form of injury.\nAblation of large portions of the scapula, or even the complete removal of that bone with part of the clavicle, and the scapulo-humeral articulation, has been had recourse to in cases of extensive injury of the shoulder, as from gunshot wounds. (Larrey.)\nIn the H\u00f4pital des Invalides at Paris may be still seen living examples of the success which sometimes attends even such severe mutilations; whilst the records of British surgery also furnish successful instances of the complete removal of the scapula, scapular end of the clavicle, and upper extremity, for tumours of great magnitude occupying the region of the shoulder, of which the cases by Mr. Fergusson and the late Mr. Liston are amongst the most remarkable.\n(B. Geo. M'-Dowel.)\nSCROTUM. Latin, per metath. a scor-tum, i. e. pellis ; KipvKog, b<rx\u00a3og, \u00f4yf\u00f9\u00e7, Gr. ; der Hodensack, Germ. Neither the English nor French language appears to have retained any word exclusively significant of this part of the body. In the former tongue, the Saxon word \u201ccod,\u201d a husk, or shell, or bag, seems to have been originally applied to it in common with other tegumentary tissues ; e. g. \u201c peascods.\u201d Subsequently, however, the meaning of the word was extended, and from the containing tissues came to imply the contents. It is now obsolete, and the only term popularly retained in both languages is \u201c the purse,\u201d \u201c les bourses,\u201d either in allusion to the scrotum resembling a purse, or from its tegumentary nature ([\u00dfvpaa, pellis).\nThe scrotum is the pouch or fold of integument in which the testicles are placed, where they occupy an external position. It is composed of skin and areolar tissue, and is plentifully supplied with vessels and nerves. It contains the testicles, their cremaster muscle, and serous membrane, together with their arteries, veins, nerves, and efferent duct, and a considerable length of the spermatic cord, which continues these into the abdominal cavity.\nThe skin of the scrotum is continuous above and in the middle line with that which covers the inferior or urethral surface of the penis, and on each side with that of the lower part of the belly, the inguinal region, and the inner side of the thigh ; behind, it is continuous with the perineum. Its colour is darker than the neighbouring integument, and in the adult its surface is sparingly occupied with hair ; in health it is rendered irregular by the presence of numerous rug\u00e6 or furrows, the larger of which take a transverse direction. The median line offers a prominence which extends backwards to the anus, and which, from its likeness to a suture, modern anatomists have named the raphe* (pcitpi}, sutura).\nThe areolar tissue of the scrotum is continuous with, or, in anatomical language, derived from, that of the perineal and inguinal regions. The more superficial or subcutaneous fascia, together with that deeper layer which is attached to Poupart\u2019s ligament and to the ramus of the pubes, converges towards the scrotum ; the two layers uniting to en-sheath the spermatic cord and testicle of each side in a cylindrical prolongation, the apposition of the two bags in the middle line forming a common partition, the septum scroti.\nThe texture of this covering of areolar tissue is peculiar, or even sui generis, and perhaps led to its receiving the appellation of the dartos (p\u00e2pro\u00e7, tunica). It is very delicate, and highly elastic, and is usually of a reddish or pink colour ; but it is not unlikely that this phenomenon may be of post-mortem occurrence : and it has the additional peculiarity of being destitute of the fat which is\n* Its proper Greek name is tyfe. The etymology of the word is unknown, but it is used by Aristophanes and Galen.","page":438},{"file":"p0439.txt","language":"en","ocr_en":"SECRETION.\nfound in connection with this tissue in most parts of the body. Later researches have shown a still farther difference, viz. the possession of another structure \u2014 the unstriped or organic muscular fibre \u2014 which is either not present in the subcutaneous textures of other regions, or is in far more sparing quantity. The contractility which is the function of these fibres is quite independent of the will, and is not only readily developed on the application of a direct stimulus, but is also producible by cold, and is associated with general tonicity of the system. And in opposite conditions of warmth or debility, a relaxation of these fibres effaces the rugae which their contraction had previously produced.\nThe vessels of the scrotum are numerous, but of little surgical importance ; they are derived from those of the thigh and perineum. The superior and inferior external pudic, from the femoral artery, terminate by sending many small twigs to the integuments of the penis and scrotum ; while, posteriorly, the internal pudic of each side sends forwards a superficial perineal branch, which likewise ends in these tissues, by ramifying and anastomosing with the preceding. The accompanying veins have in all respects a corresponding distribution.\nThe nerves are chiefly the anterior terminations of those seen in the perineal space. Thus on each side is the inferior pudendal, which leaves the sacral plexus with the small sciatic nerve; while, nearer the median line, are the two superficial perineal nerves (external and internal perineal). The branches of these are very numerous, and are traceable to the front of the scrotum. The ilio-in-guinal, a small branch from the higher part of the lumbar plexus, and which perforates the abdominal muscles, together with a part of the genito-crural nerve from the same source, terminate near the front of the scrotum, but extend very little on it.\nFor the anatomy of the contents of the scrotum, as well as its morbid appearances, the reader is referred to the article \u201c Testicle,\u201d in which they will be included.\n( William Brinton.)\nSECRETION.\u2014This term is usually employed to designate the process of separation of those matters from the nutritious fluids of the body, which are destined, not to be directly applied to the nutrition and renovation of its organised fabric, but (1) to be either at once removed as injurious to its welfare, or (2) to be employed for some ulterior purpose in the chemical or physical processes of the economy itself, or to exert some kind of action upon other beings. The term is often used, also, to designate the products thus separated.\nThe nature of this process of separation is essentially the same in all cases, whatever may be the destination of its products ; and we shall consider it, therefore, in the first place, without any further reference to them, than may suffice to indicate the boundaries of the three groups under which we have ar-\n439\nranged them. It is probable that in almost every act of secretion a double purpose is served, the blood being freed from some ingredient whose accumulation would be superfluous, if not injurious ; and the fluid separated having some secondary purpose to answer. Thus, whilst biliary matter becomes a positive poison if it be retained in the blood, it serves an important purpose, when poured into the duodenum, in completing the digestive process, and in preparing the nutrient contents of the intestinal canal for absorption. So, again, the cutaneous exhalation not only removes the superfluous water of the blood, but is one of the chief means of regulating the temperature of the body; whilst the sebaceous matter, poured forth by the glandul\u00e6 of the skin, serves to lubricate its surface, at the same time that it relieves the blood of matter which, not being nutritive, is extraneous. Even the urine, which seems to be eliminated merely for the removal of noxious matters from the blood, is sometimes made to serve an additional purpose, its acridity, or its peculiarly offensive odour (increased under the influence of terror), frequently rendering it an effectual means of defence. On the other hand, the substances which are separated from the blood for the purpose of discharging some important office in the economy, usually, if not always, contain some substances whose retention in the blood would be injurious, and which are therefore advantageously got rid of through this channel. Thus the salivary, the gastric, and the pancreatic fluids all contain an animal principle nearly allied to albumen ; but this principle seems to be in a state of change, or of incipient decomposition ; and it would seem not improbable, that whilst this very condition renders the albuminous matter useful in promoting the solution of the aliment, it renders it unfit to be retained within the circulating current.\nIt is impossible, therefore, to divide the secreted products strictly, as some have attempted to do, into the excrementitious and the recrementitious ; that is, into those which are purely excretory in their character, and those which are subservient to further uses in the economy ; most, if not all of them, partaking more or less of both characters. Still we may group the secreting processes for practical purposes, according to the predo* minance of one or other of the objects enumerated above ; those being arranged under the first division, in which the depuration of the blood is manifestly the chief end, any other being rendered subservient to this, as is the case pre-eminently with regard to the urine ; those being classed under the second, in which the ulterior purpose of the separated fluid would seem to be the principal occasion of its production ; and this second group being subdivided, according as this ulterior purpose is connected with the operations of the economy itself, as is that of the tears, the saliva, the gastric fluids, &c., or is destined to act upon some other, as is the case with the milk, the odorous secretions, &c.\nF F 4","page":439},{"file":"p0440.txt","language":"en","ocr_en":"440\tSECRETION.\nAnother classification has been proposed, of which the foundation is the degree of resemblance of the secreted products to the normal constituents of the blood ; those being associated into one group, whose characteristic ingredients are altogether unlike those of the blood ; and a second group being formed of those, whose elements seem nearly allied to those of the blood. This classification is practically almost the same with the preceding ; for, as we shall hereafter see, all the cases in which the secreted products are very unlike the constituents of the blood, are those in which they are most directly and speedily removed from the body ; whilst those in which they serve some ulterior purpose, are for the most part also those, whose elements differ least from the components of the blood.\nThe first group of these processes corresponds with that which has been elsewhere treated of under the head of Excretion; and the resultant products have been termed excrementitious secretions, or more briefly excretions, in contradistinction to the recremen-titious secretions, which are the products destined for ulterior uses.\nThere is another group of processes, which corresponds so completely with the secreting operations in its general nature, that it is difficult to avoid placing it under one category with them; the more especially, as the instruments by which it is effected correspond with the organs of secretion in the most essential features of their structure. We refer to that elaborating agency, which is now generally believed to be exerted upon certain materials of the blood by the spleen, thymus, and thyroid glands, and suprarenal capsules (which are sometimes collectively termed vascular glands), and also by the glands of the absorbent system-. The \u201c vascular glands,\u201d as will presently apjpear, exactly correspond with ordinary glands in all that part of their structure by which they withdraw or eliminate certain matters from the blood ; and they differ only in being unprovided with excretory ducts for the discharge of the product of their operation. These products, instead of being carried out of the body, are destined to be restored to the circulating current, apparently in a state of more complete adaptiveness to the wants of the nutritive function ; in other words, these vascular glands are concerned in the assimilation of the materials that are destined to be converted into organised tissues, instead of being the instruments of the removal of the matters which result from the disintegration or decay of those tissues. And in regard to the entire absorbent system, with its glandul\u00e6, reasons will be presently advanced for regarding it all as one great secretory apparatus, whose relations are essentially antagonistic to those of the excreting apparatus ; the materials of its operation being derived from the external world, and its products being poured into the blood ; and its purpose being to supply fresh pabulum to the circulating fluid, whose effete matters are being drawn off by the eliminating agency of other\nglands, whose products are carried back to the external world.\nThe line of demarcation between the functions of nutrition and secretion can scarcely be drawn with definiteness ; so close is the affinity between the two sets of operations, both in their nature and in their purpose. For, as will presently appear, every act of true secretion is really a part of the nutritive process, the selection of the materials on which the secreting organ acts being effected by the development of certain groups of cells, which, during their short period of existence, form a part of the solid constituents of the body ; so that, as was first pointed out by Professor Goodsir, the functions of nutrition and secretion are essentially the same in their nature. In regard to the objects of the two functions, moreover, there is not that difference which might at first sight appear ; for although the nisus of the nutritive functions is directed towards the increase and maintenance of the solid fabric, and that of the secreting operations to the removal of certain fluids from the circulating current, the retention of which would be injurious, yet here again there is much common ground. For, as was first pointed out by Treviranus, \u201c each single part of the body, in respect of its nutrition, stands to the whole body in the relation of an excreted substance ; \u201d in other words, every part of the body, by taking from the blood the peculiar substances which it needs for its own nutrition, does thereby act as an excretory organ, inasmuch as it removes from the blood that which, if retained in it, would be injurious to the nutrition of the rest of the body. Thus the phosphates which are deposited in our bones are as effectually excreted from the blood, and prevented from acting injuriously on the other tissues, as are those which are discharged in the urine.\nThe application of this idea has been thus felicitously extended by Mr. Paget*:\u2014\u201c The influence of this principle may be considered in a large class of outward growing tissues. The hair, in its constant growth, serves, over and above its local purposes, for the advantage of the whole body ; in that, as it grows, it removes from the blood the bisulphide of proteine, and other constituents of its substance, which are thus excreted from the body. Now this excretive office appears, in some instances, to be the only one by which the hair serves the purpose of the individual ; as, for example, in the foetus. Thus, in the f\u0153tus of the seal, and 1 believe of most other mammals, removed as they are from all those conditions against which hair protects, a perfect coat of hair is formed within the uterus, and very shortly after birth is shed, and replaced by another coat of wholly different colour, the growth of which had begun within the uterus. Surely, in these cases, it is only as an excretion, or chiefly as such, that this first growth of hair serves to the advantage of the\n* Lectures on Nutrition, Hypertrophy, and Atro* phy. London Medical Gazette, 1847.","page":440},{"file":"p0441.txt","language":"en","ocr_en":"SECRETION.\nindividual. The lanugo of the human foetus is an homologous production, and must, I think, similarly serve in its economy, by removing from the blood, as so much excreted matter, the materials of which it is composed.\n\u201c Now if this be reasonable, we may carry this principle to the apprehension of the true import of the hair, which exists in a kind of rudimental state on the general surface of our bodies, and to that of many other permanently rudimental organs, such as the mammary glands of the male and others. For these rudimental organs certainly do not serve, in a lower degree, the same purposes as are served by the homologous parts which are completely developed in other species, or in the other sex. To say they are useless, is contrary to all w|\u00e4 know of the absolute perfection and all-pjrvading purpose of creation ; to say they exist\\merely for the sake of conformity with a general type of structure, is surely unphilo-sophical ; for the law of unity of organic types is, in larger instances, not observed, except when its observance contributes to the advantage of the individual. No ; all these rudimental organs must, as they grow, be excretions serving a definite purpose in the economy by removing their appropriate materials from the blood, and leaving it fitter for the nutrition of other parts, or adjusting the balance which might else be disturbed by the formation of some other part. Thus they minister to the self-interest of the individual ; while, as if for the sake of wonder, beauty, and perfect order, they are conformed with the great law of unity of organic types, and concur with the universal plan observed in the construction of organic beings.\u201d\nWe cannot have a better example of the close affinity between the functions of nutrition and secretion, in regard alike to their essential nature and to their purpose, than that which is afforded by the structure, growth, and offices of the adipose tissue. Fat, wherever it exists, whether in large isolated masses, or dispersed through areolar tissue, is made up of an aggregation of minute cells, whose peculiar province it is to draw into themselves the superfluous oleaginous matter of the blood, as a part of the history of their own development. Since they form constituent parts of the organism, and may possess as great a duration as that of any other of the elements of the soft tissues of the body, the growth of fat cells is commonly regarded as an act of nutrition. But it may also be considered as an act of secretion ; for it is the means of separating from the blood a product which is not destined to undergo any further organisation, and whose accumulation in the circulating fluid, beyond a very small and limited amount, would be positively noxious. This very same act of elimination of fatty matter, when performed by the cells of the liver, or of the sebaceous follicles of the skin, or (abnormally) by those of the kidney or of the intestinal glandulae, is recognised as forming part of the function of excretion, the difference being simply in the position and re-\nlations of the secreting cells. For whilst those of the glands are placed upon or near the free surfaces of follicles or ducts, and are destined from the first to a speedy exuviation, those of fat are woven up with areolar fibres and membranes, and form solid masses of tissue. A distinction might be drawn, on the ground that the contents of the fat cells are destined to be again taken into the circulation ; whilst those of glandular cells, having been once eliminated from the blood, are never to return to it. But this would not hold good ; for the fat cells appear to have an indefinite duration, the reception of their contents into the circulating current seeming entirely to depend upon the demand for these in the blood* ; and there is now sufficient evidence that a considerable part of the bile that has been secreted and poured into the intestinal canal is destined for re-absorption. And if we admit that the spleen, thymus and thyroid bodies, and supra-renal capsules, are to be regarded as possessing a glandular character, although the products of their elaboration are destined to be received back again into the current of the circulation, it is difficult to find a reason for the exclusion of a mass of adipose tissue from the same category.\nOf the organs of secretion. \u2014 In order that we may duly understand the real nature of the secreting process, as elucidated by recent discoveries, it is requisite that we should examine into the nature of the instruments by which it is effected. There can scarcely be a more beautiful illustration of the doctrine that physiology is as capable as any other science of being reduced to general principles, and that these principles must, if valid, be of universal operation, than the fact that the process of secretion \u2014 common as it is in all its essential features to the animal and vegetable kingdoms\u2014is every where performed by the same agency, namely, the development of simple cells, each possessing its own independent vitality ; these bodies forming the really operative part of every secreting\n* May not this re-entrance be governed simply by physical laws ? There can be no question that the chief purpose of fat is to serve as a store of combustible matter, for the maintenance of the heat of the body, when there is a deficiency of materials in the blood. A certain proportion of fatty matter (from 4 to 6 parts in 1000) seems normally to exist in the blood ; and this is usually renewed from the food as rapidly as it is eliminated by the respiratory process, or by the nutrition of the nervous tissue. Jiut if the supply be withheld, a diminution of the quantity of oleaginous matter in the circulating current must rapidly take place ; and it is then that we find the contents of the fat-cells reabsorbed into the blood. It has been shown by Matteucci that oleaginous matter will pass through a membranous septum towards a slightly alkaline fluid, such as the blood ; and it does not seem difficult to understand, therefore, how the fat-cells should give up a portion of their contents when the alkalinity of the blood is no longer neutralised by the fatty matter which it normally contains, and how just that amount should pass back again, which is necessary to keep up the due proportion of fatty matter in the blood, and no more.","page":441},{"file":"p0442.txt","language":"en","ocr_en":"442\nSECRETION\norgan, however complex its structure may be. The progress of comparative anatomy has shown that neither the form nor the internal arrangement of the parts of a gland could have any essential connection with the nature of its product (see Gland) ; since even those glands (the liver and the kidney, for example) in which there is the greatest complexity of structure, make their first appearance at the lower end of the animal series, as in the early embryo of the very highest, in the simplest possible form. Still something was wanting to prove that the structural elements immediately concerned are in all instances the same; and there seemed no analogy whatever between the secreting membrane of the animal and the secreting cell of the plant. The doctrine was first propounded by Purkinje * and Schwannf, adopted and extended by Henle and fully confirmed by the researches of Goodsir $ and Bowman ||, that the true process of secretion \u2014 under whatever form it may present itself\u2014is always performed by the intervention of cells; which, as part of their own regular vital actions, select and withdraw certain ingredients from the nutritive fluids, and afterwards set them free again, generally by the rupture or dissolution of the cell-wall, but sometimes perhaps by a simple act of transudation. For the proper comprehension of this doctrine in all its generality, it is necessary to give some attention to the history of cell-development, as manifested in the simplest forms of organic existence ; those cryptogamie plants, namely, in which every cell is a distinct and independent individual.\nThe earliest condition of such a cell is a minute molecule, which cannot be discerned except under a considerable, magnifying power, and in which even the highest amplification fails to exhibit any distinction of parts. When placed under circumstances favourable to its development,\u2014 namely, when supplied with the materials of its nutrition, and stimulated by the requisite degree of warmth,\u2014this germ increases in size; and a distinction becomes apparent between its transparent exterior and its coloured interior. Thus we have the first indication between the cell-wall and the cell-cavity. As the enlargement proceeds, the distinction becomes more obvious ; the cell-wall is seen to be of extreme tenuity and perfectly transparent, and to be homogeneous in its texture, whilst the contents of the cavity are distinguishable in the Alg\u00e6 by their colour, which is green in the Chlorococci, and bright red in the H\u00e6ma-tococci ; but in the simple fungi, such as the Torula cerevisii, or yeasf plant, they are colourless. The contents of the cell-cavity\n* Isis, 1838, No. 7.\n+ Froriep\u2019s Notizen, Feb. 1838.\nI_____\t\u00b1 a 1 \u2022 \u00cf OOO \u201e\t1 A/1\n1842, \u201c On the Structure and Uses of the Malpighian Bodies of the Kidney.\u201d\nhave no relation whatever to the material of the cell-wall. Of this we have a remarkable example in the cases just cited ; for whilst the red and green coloured products of the Algae are probably nearly related to each other and to the chlorophyll of higher plants, being simple ternary compounds of water and carbon, the cell-contents of the yeast-plant are closely allied to the protein compounds ; and yet the cell-walls in both instances are composed of the same material, cellulose. It is evident, then, that the inherent powers of the cell are not confined to the application of nutrient materials to the extension of its own walls, and the consequent enlargement of its cavity ; but that they are exercised also in selecting from (and it maybe in combining or modifying) the same materials, in order to fill this cavity with a certain product, which may be altogether different in its constitution and its properties from that of which its wall is composed. This latter process is as essential to our idea of a living cell, as is the growth of its wall ; and must never be left out of view when the history of cell-development is being considered.\nThe nature of the compound thus stored up in the interior of a cell depends in part upon the original inherent endowments of the cell itself, derived from its germ ; and, in part, upon the character of the nutriment supplied to it. Thus we find that the simple Alg\u00e6 will grow wherever they can obtain, from the air and moisture around, the elements of their cell-walls and of their cell-contents ; which elements they have themselves the power of combining into those peculiar compounds, of which analysis shows that they are composed. But out of the very same materials, and under circumstances to all appearance identical, the Chlorococcus manufactures a green product, and the Haemato-coccus a red one. On the other hand the yeast-plant, like the fungi in general, will only grow where it meets with an azotised compound already formed ; and from this it elaborates the product which occupies its cell-cavity, its cell-wall being apparently formed by the same process as that of the simplest Alg\u00e6. It could no more vegetate, as they do, upon cold damp surfaces, than they could develop themselves in a solution of fermentible matter secluded from the light.\nA similar variety of function is seen amongst the cells, whose aggregation makes up the structure of any one of the higher plants, and which are all the descendants of the single cell which constituted its original germ. Thus we have in the green cells of the leaves the representatives of the simple Chlorococci ; these, under the influence of solar light, combining the carbon which they derive from the atmosphere, or from the soil, with the water transmitted from the roots, and elaborating these elements into a variety of new products, amongst which chlorophyll and cellulose are still prominent ; but also operating upon the azote which they draw from the atmosphere","page":442},{"file":"p0443.txt","language":"en","ocr_en":"SECRETION.\nor from the soil, and combining this with the other three elements into quaternary compounds, that seem destined rather for the nutrition of animals than for any special purpose in the economy of the plant itself. The contents of the cells of the leaves are thus of a very complex nature; their life not beginning and ending with themselves, as is the case with that of the independent organisms, which in other respects they resemble ; but having relations to the rest of the structure, for which, in fact, it is their function to prepare the 'pabulum. For the elaborated sap or nutritious fluid, which is the product of their agency, is transmitted through the entire fabric, and furnishes each portion with the materials of its development and extension, which in every instance is effected by an act of cell-growth. All parts select from it the same substance for the formation of the cell-walls, but the cell-contents are different in every organ and variety of tissue. Thus we find one set of cells drawing in starch, another fixed oil, another resin, another volatile oil, another colouring matter, another sclerogen, another protein compounds, and so on ; and this with the greatest uniformity and regularity. We may frequently see that even contiguous, and in other respects similar, cells, in the same organ, either select from the common pabulum a different compound, or exercise upon the same compound a different influence. Thus we observe in the particoloured petal of a hearts-ease or tulip, certain stripes or patches of different hues, which, when examined with the microscope, are found to consist of cells that differ from each other only in the colour of their contents. A precisely similar phenomenon is presented by the epidermic cells, which constitute the scales of the wings of Lepidoptera.\nIn all these cases, however, the products which are separated from the circulating fluids are stored up within the component cells of the fabric, instead of being cast forth from it ; and although the term secretion is commonly applied to the process, yet it would be just as correct to regard it as part of the function of nutrition. It is, in fact, exactly on the same footing with the production of fat in animals.\nThe absence of necessity for any other form of excretion in plants, than that which is carried on through the respiratory process, may be accounted for without much difficulty. A large proportion of the vegetable fabric is (from the nature of its chemical constitution) but little prone to decomposition, and possesses a character so permanent, that it may remain almost unchanged for an indefinite time; and those parts which are of softer texture and more actively employed in the vital processes, and which are therefore more prone to decay, are periodically thrown off and renewed. In animals, on the other hand, all the softer tissues have a strong tendency to disintegration, in virtue of their peculiar composition ; and in some of them a destructive chemical change seems to be the very\ncondition of their functional activity. For the maintenance of their vital energy, therefore, there is needed not merely a constant supply of new material, but a continual removal of the effete particles. On this last operation, indeed, the continuance of the vital activity of animals is more closely and immediately dependent, than it is upon the supply of aliment ; for whilst the latter may be interrupted for a period of considerable duration without producing more than debility, the former cannot be checked for many hours (in the warm-blooded animals at least) without a fatal result. Indeed, if we consider respiration as one of the excreting processes (which it undoubtedly is in a broad and philosophical acceptation of the latter term), we must say that the liberation of effete particles may not be suspended for more than a few minutes without death ensuing.\nTurning our attention, then, in the first instance, to the excretory organs of animals, we may define them to be groups of cells, placed on the free surface of a membrane, which is directly continuous with that of the exterior of the body, whilst its attached surface is in relation to the blood-vessels, &c. of the interior ; so that these cells, having grown and developed themselves at the expense of the materials supplied by the blood, are either cast off entire and conveyed away, or give up their contents by the rupture or deliquescence of their walls ; the products which they have selected or eliminated being thus, in either case, entirely got rid of from the interior of the fabric. The disposition of the membrane on which the cells lie, whether it be spread out on a plane surface, depressed into short rounded follicles, or extended into long and convoluted tubes, is a matter of secondary consequence ; nor is it of more importance whether the follicles be isolated, and discharge their contents by separate outlets, as those of the skin or mucous membrane (fig. 307.), or whether they are aggregated in clusters, and\nFig. 307. (Fig. 209. Vol. II.)\nGlandular follicles in ventriculus succenturiatus of Falcon and other birds. (After M\u00fcller.')","page":443},{"file":"p0444.txt","language":"en","ocr_en":"444\tSECRETION.\nopen into a common channel, like those of the liver of the lobster or cray-fish (fig. 308.) ;\nFig. 308. (Fig. 214. Vol. II.)\nLobule of the liver of Astacus fluviatilis. (.Muller.)\nnor, again, whether the tubes are few and of great length, lying loose in the cavity of the body, and passing from one end of it to the other, like the biliary vessels of insects\nFig. 309. (Fig. 431. Vol. II.)\nAlimentary canal of Pontia brassica.\n(fig. 309.) ; or whether they are very numerous, of less proportional length, and aggregated in a compact mass, as in the kidney of the higher animals.\nIn all instances, then, the excretory organ essentially consists of a limitary membrane, which forms part of the integument of the body, or of one of its involutions ; and of cells covering the free surface of that membrane, and, consequently, in direct relation with the external surface. Thus we have the limitary membrane of the true skin, and of the mucous membrane of the alimentary canal which is directly continuous with it, sunk into follicular depressions ; and the free surfaced\nof these are lined with cells, the layers of which are continuous with those of the epidermis and of the gastro-intestinal epithelium respectively. (See Mucous Membrane.) We trace inwards another extension of the same membrane along the genito-urinary passages, up to the kidneys, where it forms the walls of the tubuli uriniferi ; and there, too, its free surface is covered with an epithelial layer of cells, which is the efficient instrument of the selection of the constituents of the urinary fluid, and which, when exuviated, is conveyed along the urinary passages to the exterior of the body. So, too, the hepatic cells, by which the biliary matter is eliminated from the blood, are brought into direct continuity with those of the external surface, through the hepatic ducts and gastrointestinal mucous membrane.\nThe case is not different, in any essential respect, with regard to the organs by which the recrementitious secretions are formed. Thus the lachrymal, salivary, pancreatic, and mammary glands are in like manner composed of a continuation of the limitary membrane of the true skin, or of the mucous membrane lining the alimentary canal, involuted into tubes and follicles, the free surfaces of which are covered with epithelial cells. These cells, drawing into themselves certain constituents of the blood, are cast off when they have completed their full development ; and their contents, set free by the disintegration of the cell-walls, are carried off by the ducts, which collect them from different portions of the glandular structure, and deposit them in the situation where the purposes of the secreted product are to be answered.\nIf we attentively consider the character of what is commonly designated as the absorbent system, we shall see that this, too, may be regarded as a glandular apparatus ; possessing, as it does, the essential characters of a gland in regard to its structure, and being analogous to the true glands in its mode of performing its function, and the difference of its purpose in the general economy being accordant with the difference of its anatomical relation. Putting out of view for the time the absorbent glands, or ganglia, we find the absorbent system to consist of two series of long tubuli, one set extended through almost the entire body, whilst the other is distributed upon the intestinal canal. These tubes appear to commence either in caecal origins or in loops ; they coalesce with each other; and at last discharge themselves into a common receptacle, just as do the tubuli of the kidney. That their origins should be widely scattered, instead of being bound together in one compact mass, is a fact of no physiological importance ; having reference only to the remoteness of the sources, whence are derived the materials on which the particular agency of this apparatus is exerted. These materials are of two kinds ; for they consist in part of the crude materials selected by the lacteal division of the system from the contents of the alimentary tube, over whose walls the origins of the","page":444},{"file":"p0445.txt","language":"en","ocr_en":"SECRETION.\nlacteals are dispersed; and in part of substances taken up by the lymphatic or interstitial division, and probably consisting chiefly of particles which are set free by the continual disintegration of the living structure, but which, not being yet decomposed, are capable of being again employed for the purposes of nutrition. The materials derived from these sources appear to require a considerable preparation or elaboration, before they are fit to be introduced into the current of the circulation ; and this elaboration is effected by an agency of precisely the same nature with that which is concerned in the removal of various products of secretion from the blood ; for the tubuli of the absorbent system, like those of the kidney or the testis, are lined by epithelial cells, and their duty seems to be altogether analogous. The alterations which the absorbed matters undergo during their passage along this system of tubes, and the evidence that these alterations are in great part due to the elaborating action of cells, having been heretofore considered (see Nutrition), need not be again dwelt on ; but a few words maybe added respecting the structure and functions of the glandulae or ganglia, with which the absorbent vessels of man and the mammalia are copiously furnished. These bodies are composed of lacteal or lymphatic trunks, convoluted into knots, and distended into cavities of variable form and size, which are known as the \u201c cells \u201d of these glands. Amongst these cells there is a copious plexus of blood-vessels, but there is no direct communication between their cavities. According to Prof. Goodsir *, the epithelium which lines the absorbent vessel undergoes a marked change where the vessel enters a gland, and becomes more like that of the proper glandular follicles in its character. Instead of being flat and scale-like, and forming a single layer in close apposition with the basement membrane (as it does in the lacteal tubes before they enter the gland, and after they have emerged from it), we find it composed, within the gland, of numerous layers of spherical nucleated cells, of which the superficial ones are easily detached, and which appear to be identical with the cells that are found floating in the chyle and lymph, especially after their passage through these bodies. The absorbent glands may be regarded, therefore, as concentrating within themselves that agency, to which the whole system of tubuli is more or less subservient. Such an idea is strictly accordant with the facts of comparative anatomy; for in reptiles, in which there are no glands, the tubuli or vessels are enormously lengthened by the convolutions which they present along their course, as if to furnish a sufficient extent of epithelial surface.\nThere is strong reason for regarding the spleen, the thymus and thyroid glands, and the supra-renal capsules, as parts of the same assimilative apparatus, their office apparently\n* Anatomical and Pathological Observation 1% 46.\n445\nbeing, to withdraw certain crude matters from the blood, to submit these to an elaborating action whereby they shall be rendered more fit for the nutrition of the tissues, and then to restore them to the circulating current. The details of the structure of these organs will be found under their respective names; and it will be sufficient to state here, that they all show an essential correspondence with the true and recognised glands in every respect but this, that they have no efferent ducts. Each of them may be described as consisting essentially of a number of vesicles, which are either closed and isolated, or open into a common reservoir, which is itself closed ; the vesicles in either case are lined with epithelial cells.* Around these, as around the follicles or tubuli of the true glands, blood-vessels are copiously distributed ; and the elimination of products from the blood appears to be effected by their agency, precisely as if these products were destined to be cast out of the body. The mode in which they are taken back into the circulation, after they have been subjected to the elaborating process, is not very clear; both blood-vessels and absorbents have been supposed to participate in the operation ; and this idea may not be regarded as improbable, when the large size and number of the lymphatics distributed to these organs is considered.\nHaving thus taken a general survey of the principal varieties of secretory structure, and of the fliief aspects under which the secreting function presents itself, we shall pass on to a more particular consideration of the mode in which this operation is performed, and of the instruments by which it is effected. For this purpose it will be preferable to select a particular gland, and to examine the minuti\u00e6 of its structure in the most diverse forms and conditions under which it presents itself; and there is none which suits our purpose so well as the liver, which is the gland of most universal existence throughout the whole animal series, and which presents almost every leading variety that is found in the whole series of glandular structures. And we gladly avail ourselves of the opportunity thus afforded, of bringing the account already given of that gland (see Liver) into conformity with the increased knowledge of its structure that has been since acquired.\nThere are few animals possessed of a distinct digestive cavity, in which some traces of a biliary apparatus (recognisable by the colour of the secretion) may not be distinguished. Thus in the Hydra, some of the cells that form the lining of the stomach contain a brownish-yellow matter, strongly resembling bile, which is probably poured into the cavity on the rupture of the cells. In the walls of the stomach of the Actinia, Dr. Thomas Williams has described sulci formed by du plicatures of the lining membrane, in which are lodged a set of cells of glandular appearance, some\n* See Prof. Ecker, in Annales des Sciences Naturelles, Zoologie, Ao\u00fbt, 1847.","page":445},{"file":"p0446.txt","language":"en","ocr_en":"446\tSECRETION.\nof them containing scarlet-red, and others bright yellow granules ; the latter are regarded by Dr. W., and probably with justice, as the diffused rudiments of a liver.* In the Boiver-bankia densa, and in other Bryozoa, very distinct spots may be seen in the parietes of the stomach, which seem to be composed of clusters of biliary cells contained within follicles ; and during digestion, the contents of the stomach are seen to be tinged with a rich 3'ellow-brown hue, derived from the matter discharged from these follicles.-}' In the Asterias the digestive cavity is surrounded by a more complicated glandular apparatus, but it seems difficult to determine the precise portion of this which discharges the function of a liver. The central stomach is furnished with a pair of glandular appendages, each composed of a cluster of follicles, which open into its fundus ; and these, from their dull yellow colour, have been thought to be a liver. Dr. Williams states, however (loc. cit.), that their ultimate structure does not sanction that idea, the terminal vesicles abounding in a white elastic tissue, in the meshes of which are entangled a number of small, compact, and granular cells, which are by no means hepatic in their aspect. He is disposed to agree with Dr. Grant, who hints that this organ may be a rudimentary pancreas ; we should, ourselves, regard it as more probably a salivary gland, its secretion being apparently mingled with the food immediately upon the ingestion of the latter. In the walls of this central stomach, proper gastric follicles have been detected by Dr. Williams; and he regards in the light of an hepatic organ the dilated culs-de-sac, filled with large glandular cells, which are disposed in great numbers along the ramifying c\u00e6cal prolongations of the central stomach that are extended into the rays.\nIn the lower groups of the Articulated series, we meet with a diffused form of the biliary apparatus, not unlike that which has been just described in the lower Radiata. Thus in the Earthworm, the large annulated alimentary canal is completely encased in a flocculent external coating, which, when examined with the microscope, is found to consist of a mass of minute flask-shaped follicles, held by tubular peduncles, several of which coalesce to form the excretory canals for the discharge of the secretion into the digestive cavity. These follicles are composed of a membrane of extreme tenuity, and their interior is filled with cells containing granular matter and oil globules, which are the constituents of the hepatic secretion. In the Leech and some other Annelida, the alimentary canal is furnished with large sacculated appendages ; and in the walls of these, as well as of the central canal, the biliary cells are closely disposed. These cells, according to Dr. Williams, are not included within follicles, as in the earthworm ; the absence of c\u00e6cal multi-\n* Guy\u2019s Hospital Reports, 1846, p. 280.\nt Dr. A. Farre, in Phil. Trans. 1837.\nplications of the stomach in the latter being compensated by a concentration of parts in\nFig. 310. {Fig. 69. Vol. I.)\nAlimentary canal of Leech, with c\u00e6cal prolongations.\nthe biliary system. In the Myrapoda, there is a decided advance from this diffused form of hepatic structure, towards that more concentrated and isolated condition, in which we find the liver of Insects. The general distribution of the biliary organs in this class has already been described. (See Insects, Vol. II. p. 974.) They consist of a number of distinct filiform tubes, usually of a yellowish-brown colour, placed in close apposition to the sides of the alimentary canal, and opening into it near the pyloric extremity of the stomach, usually by separate- orifices, but sometimes after the junction of two or more with each other, to form short common trunks. Their number varies considerably; the fewest, namely four, existing in the Datera, six being found in the Lepidoptera, and many more in the Orthoptera and Hymenop-tera. When few in number, they are very long, sometimes three or four times the length of the alimentary canal, and are tortuous and convoluted ; when numerous, they are proportionally short, and are more delicate in structure. In many larvae, they are furnished with lateral caeca, but these almost always disappear as the insect approaches the imago state. The following is the description recently given of the minute structure of the biliary tubuli, by a well qualified observer : \u2014 \u201c When more intimately examined, these tubes are found to consist of a delicate tube of clear, transparent, amorphous basement membrane, the inner surface of which is covered with secreting cells. From the thinness of the tube, the cells often project, so as to give it a granulated appearance when","page":446},{"file":"p0447.txt","language":"en","ocr_en":"SECRETION.\nviewed by the naked eye, as in the flesh-fly, Musca carnaria (fig. 31J. a, b) ; and generally\nFig. 311.\nBiliary Organs of Musca carnaria.\na, portion of a trank and two branches of one of the biliary tubes of the flesh -fly, viewed by reflected light, and magnified eight diameters ; b, portion of a biliary tube of the flesh-fly highly magnified, exhibiting the arrangement of the secreting cells, and the mode of distribution of the trache\u00e6 ; c, a secreting cell from the liver of the flesh-fly, very highly magnified. (After Leidy.')\ntowards the free extremities the sides of the tubes are so irregular, that they appear as if merely folded upon the secreting cells to keep them together. The secreting cells are round, oval, or nearly cylindrical from elongation. Their average measurement is about \u201809 milliin. The contents are white, yellowish, or brownish, and consist of a finely granular matter, numerous fine oil globules, a granular nucleus, and a transparent nucleolus. The ceils in the extremity of the tubes are not more than half the size of those a little further on (or nearer the termination), and contain less granular matter and no oil globules, so that they are more distinct, and the nucleus more apparent. Upon advancing a very little, the cells are found to be of an increased size, and full of granular matter, so as considerably to obscure the nucleus from view. A little further, we \u2022 find the addition of fine oil globules, readily distinguishable by their thick, black outline when viewed in a certain focus. Sometimes the cells become so filled with oil, as to be distended with it, rendering the granular matter and nucleus so transparent as totally to destroy all appearance of the former, and the latter only is to be perceived in faint outline. Such a state I have frequently observed in Dermestes, Ateuchus, &c. The nucleus (fig. 311. c) is generally central, glo-\n447\nbular, and pretty uniform in size in the same species, averaging in measurement about '025 millim. The nucleolus is always transparent, and measures about '006 millim. The central passage of the tubes, or separation of the cells in the middle line, is usually found filled with fine granules, and a great amount of oil globules. The biliary tubes of insects are bathed in blood, or the nutritive fluid, and the respiratory trache\u00e6 are distributed to them with extreme minuteness, but are separated from the secreting cells by the intervention of the basement membrane.\u201d* According to Dr. T. Williams (op. cit.), some at least of the large cells which give the sacculated appearance to a biliary tubulus are really parent cells, filled with a second generation of hepatic cells ; they are, therefore, analogous to follicles, save that they have no proper outlet, for we shall hereafter see that the follicle in its earliest condition is probably nothing else than a parent cell. From the above description, it would appear that the hepatic cells originate towards the upper or caecal end of the tubulus, that they are gradually being pushed onwards towards the outlet by the growth of new generations behind them ; and that, as they thus advance, they acquire an increase in size by their own inherent powers of development, at the same time drawing into themselves the peculiar matters which they are destined to eliminate from the circulating fluids. The cells, having attained their full growth, and completed their term of life, give up their contents by the rupture or deliquescence of their walls, and these pass down the central cavity of the tube, to be discharged into the alimentary canal.\nIn the higher Crustacea we find a condition of biliary structure much more closely allied to that of Mollusca than to that of Insects ; the liver being a pair of massive lobulated bodies, each of them made up by the aggregation of numerous c\u00e6cal follicles, from every one of which passes off a narrow duct, to join a trunk that is common to all the vesicles on one side. \u201c In structure,\u201d says Dr. Leidy (loc. cit.), \u201c the caeca resemble the tubes of insects, being composed of a sac of basement membrane, within which, originating from the inner surface, are numerous secreting cells (fig. 312. a). The cells are more or less polygonal in form, from mutual pressure. At the bottom of the caeca the cells are small, with an average diameter of 02 millim., and contain a finely granular matter of yellowish hue, with a granular nucleus, and a transparent nucleolus. As we proceed from the bottom upwards, the cells (fe,d, c, b) are found to increase in size, and to obtain a gradual addition of oil globules, until beyond the middle of the tube, where they are found filled with oil, so as to have the appearance of ordinary fat cells, and have a diameter averaging '06 millim. From this arrangement of the cells, when a c\u00e6cum is viewed beneath the microscope, its lower half appears filled\n* Leidy, in American Journal of the Medical Sciences for Jan. 1848.","page":447},{"file":"p0448.txt","language":"en","ocr_en":"SECRETION.\n448\nwith a finely granular matter, intermingled with nucleolo-nucleated bodies, and the an-\nFig. 312.\nBiliary Organs of Artacus affinis.\na, c\u00e6cum of the liver of Cray-fish, with its contained cells ; b, c, d, e, f exhibit the progressive changes of the cells, as they advance from the bottom of the tube. ( After Leidy.)\nterior half with a mass of fat cells, the nucleus hardly visible, from the property of oil rendering organic tissues more or less transparent. The central cavity of the caeca is filled with fat globules, and a finely granular matter corresponding to that in the interior of the cells.\u201d In some of the lower forms of Crustacea, the liver is reduced to the simple condition which it presents in insects ; and there is one very curious group, that of Pyc-nogonid\u00e6, in which the biliary apparatus is as much diffused as in the Radiata. In these animals, the stomach sends caecal prolongations into the legs, and these extend nearly to their terminal claws. The walls, both of the central stomach and of its tubular extensions, are studded with brownish-yellow cells ; but beyond this there is no rudiment of any organ for the secretion of bile.\nIn the Molluscous animals, the general\nstructure of the liver closely corresponds with that which has just been described in the higher Crustacea. Among the Compound Tunicata, however, to which the Bryozoa are so nearly related that many naturalists associate them together in one group, the structure of the liver is the same as that of Bower-bankia; the hepatic follicles being isolated from each other, and lodged in the walls of the stomach, into the cavity of which they pour their secretion by separate orifices. In the Solitary Ascidians, the hepatic follicles are more developed, and cluster round the exterior of the stomach, so as to give it a shaggy appearance, very much as in the earthworm. In the Conchifera, the liver presents itself as a distinct organ, composed of numerous lobules ; each of these is made up of a cluster of tubes, terminating at one extremity in flask-shaped follicles, whilst at the other they coalesce into a few larger trunks, which discharge themselves into the digestive cavity. The follicles are filled with cells containing the biliary secretion. The structure is nearly the same in the Gasteropoda ; the ducts of the several lobules coalescing, so as to form two main trunks, by which the secretion is poured into the duodenum. The following is Dr. Leidy\u2019s account of the minute structure of the liver of the snail ; a portion of which, moderately enlarged, and showing the arrangement of the lobules, is shown in fig. 313. a. \u201c When one\nFig. 313.\nBiliary Organs of Helix albolabris.\na, portion of the liver of the snail, moderately magnified, exhibiting the arrangement of the lobules ; b, a biliary c\u00e6cum from the same liver, highly magnified.\nof the bulbiform caeca (fig. 313. b) is examined beneath the microscope, it is found to have a structure differing in no important particulars from that of the cray-fish. The cells at the bottom cf the sac (fig. 314. a, 1, 2) average","page":448},{"file":"p0449.txt","language":"en","ocr_en":"SECRETION.\n449\n*02 millim. in diameter ; those towards the stomach gives off on either side a number of other extremity about \u201904 millim. Some of branches, which usually redivide, and then\nHepatic cells of Helix albolabris.\na, 1, 2, two cells from the bottom of the c\u00e6cum ; b, 1, 2, two cells more advanced, containing numerous oil globules ; c, 1, 2, 3, three cells, containing larger oil globules ; d, a cell distended with oil; e, a cell containing nothing but six deep yellow consistent oil globules ; f a cell containing a hard yellow mass of fat ; g, a cell rupturing, and its contents escaping; h, nuclei of hepatic cells, highly magnified.\nFig. 315.\nHoiis Farrani, showing the branchial papillae. {After Alder and Hancock.')\nthe fully ripe cells (b, 1, 2) are filled with innumerable minute globules of oil, hardly distinguishable from the granular matter ; others (c, 1, 2, 3) with globules of a larger size ; some are found with from one to ten or more large, deep yellow, oil globules in the centre ; a few (/) with a hard or crystallised mass of fat in the centre ; and many (d) are distended with oil. By pressing the cells (g) between two plates of glass, the contents will be squeezed out, and the structure will be seen as follows : \u2014 the vesicular transparent, amorphous cell-wall, finely granular matter, fat globules, and a granular nucleus (h), measuring about \u201901 millim. and containing a hard transparent nucleolus. A few of the cells contain two nuclei. The blood-vessels, consisting of arteries and veins, form a rete around the bulbiform caeca, but do not appear to come in immediate contact with the secreting cells \u201d (loc. cit.). The general plan of structure of the liver of the Cephalopoda is essentially the same ; the hepatic ducts and follicles being clustered as in a raceme, and the follicles being crowded with biliary cells. In the LoligOy these follicles are described by Dr. Williams (op. cit.), as being themselves sacculated, by duplications of their membrane ; and some of the biliary cells appear as if producing a new generation within themselves.\nA very remarkable departure from the general type is presented by certain of the Nndibranchiate Mollusca, of which F.olis may be taken as the type. In these animals, the\nVOL. IV.\ngive off smaller tubes, which are continued into the branchial papillae that cover the dorsal surface (fig- 315.). \u201cThe prolongations of the branches that enter the papillae undergo a considerable enlargement and change of form ; and from the variety and brilliancy of their colouring are the chief attraction of these elegant little animals. The simplest form of this peculiar organ is met with in Eolis concinna, where it is a mere dilated tube, having its walls slightly waved, and the inner surface sprinkled with darkish granules. In E. Farrani (fig. 316. b) it still retains a considerable simplicity of structure, but becomes decidedly sacculated. The complexity is much increased in E. olivacea, in which it is produced into puckered follicles or sacculi ; but in E. papillosa (fig. 316. a) it appears to attain its highest development. The central canal is there somewhat tortuous, and gives off on all sides variously sized, irregular, blind sacs, which are crowded with little compound follicles. The whole of the inner surface is lined with a thickish layer of irregular vesicles or globules, filled with numerous granules. These last, when submitted to a high magni-fying power, are seen to be of various sizes, transparent, rounded, and nucleated. The whole of the internal surface of the gland is covered with vibratile cilia. These compound glands are evidently biliary organs, diffused throughout the several papillae, and supplying the place of a compact liver, which is wanting in the body of these animals. The stomach\nG G","page":449},{"file":"p0450.txt","language":"en","ocr_en":"SECRETION.\n4\u00f40\nand biliary organs are so intimately connected in this genus, that it is not easy to point out\nFig. 316.\nBiliary apparatus of Eolis.\nA, branchial papilla of E. papillosa, exhibiting the gland b and the duct c ; also an ovate vesicle, a, apparently an organ of defence, and at d the wall of the inner sheath ; b, branchial papilla of E. Farrani, showing the same parts. (After Alder and Hancock.)\nthe limits of each ; they appear to differ in different species. In E. papillosa, the central canal is evidently a continuation of the stomach, and the plicated internal membrane is not only continuous throughout it, but also passes into the lateral branches, which thus appear to form part of the same organ. On the other hand, we find in some species coloured granules, similar to those of the papillae, partially lining the ramifications, as in E. gracilis and others ; while in E. despecta, the central canal, all the ramifications, and the glands of the papillae, are coloured and granulated alike, implying a greater diffusion of the biliary function. The food, after being partially digested in the stomachal pouch, is driven in detached portions through the alimentary system, by the alternate contractions of the pouch and great trunks leading from it ; these contractions are only of a nature to produce an oscillatory motion, which serves to promote that intimate mixture of the alimentary matters with the hepatic and other secretions, necessary to the process of digestion.\u201d*\nThe intimate structure of the liver of Ver-\n* Alder and Hancock\u2019s Nudibranchiate Mollusca, Part n.\ntebrated animals is much more difficult of elucidation, and can scarcely be said to be yet satisfactorily determined. The organ presents more and more, as we ascend the series, a solid parenchymatous texture, which strikingly contrasts with its loosely tabulated racemose aspect, even in the highest Invertebrata. There is not the least difficulty in demonstrating that this parenchyma is composed of cells, which correspond in the nature of their contents, and, therefore, in their functional character, with those contained within the hepatic follicles of the Invertebrata ; but the point of obscurity is the relation of these cells to the biliary ducts, the arrangement of whose ultimate ramifications has been rather a matter of surmise and inference, than of actual observation. It is very interesting to find, however, that in the lowest known Vertebrate the liver exists under the same rudimental and diffused type, as that which it exhibits in the lower Arti-culata. In the Amphioxus, or lancelet, the only vestige of a distinct hepatic organ is a large c\u00e6cum prolonged from the stomach, which is lined with greenish-yellow cells. But it is pointed out by Miiller, that the intestinal canal itself has a layer of similar cells in its walls, so that the organ would seem to have the same diffused condition as that which it presents in the earth-worm. In all other fishes, however, the liver is a well-defined conglomerate gland, even the Myxinoids presenting a liver nearly as fully developed as that of the higher fishes, so that there is not here any such complete gradation as we usually meet elsewhere. Dr. T. Williams states that he has succeeded in tracing the ducts to their ultimate terminations in the liver of the Sole (Solea vulgaris), and the Flounder (Pla-tessa flexus) ; and he describes them as ramifying like those of the Mollusca, and as ending in tubular c\u00e6ca, without vesicular expansions. Within these c\u00e6ca are found the hepatic cells, which usually, as in the Invertebrata, contain a large quantity of fat.* There is a remarkable diminution in the proportion of the adipose contents of the hepatic cells, and an increase in the granular constituents, in the class of Reptiles ; and in Birds there is an almost total absence of adipose particles. The ultimate distribution of the bile-ducts, and their relation to the parenchyma, seem to be the same as in the Mammalia.\nIn the Mammalia, the liver is more or less distinctly divisible into minute lobules, each of them composed of a parenchyma of hepatic cells, through which the blood-vessels are distributed in a close and solid plexus. The hepatic cells appear to occupy the entire space left in the meshes of this plexus, the bile-ducts having been usually regarded as not traceable, under any form, into the interior of the lobule. Mr. Kiernan, however, has always regarded the bile-ducts as forming a plexus in the substance of the lobule, interlacing with the plexus of capillaries ; his belief being chiefly founded on the anastomotic distribu-\n*\nGuy\u2019s Hospital Reports, 1846, p. 323.","page":450},{"file":"p0451.txt","language":"en","ocr_en":"SECRETION.\n451\ntion of the bile-ducts in the left lateral ligament, which he considers as in itself a rudi-mental liver, exhibiting the structure of the entire organ in its most simple form. By Mr. Bowman it was supposed, that the limitary membrane forming the wall of the minute biliary ducts is not continued into the substance of the lobule, but that the epithelial lining of the ducts is continuous with the mass of hepatic cells which forms its parenchyma. There is an a priori improbability in such an idea, which would leave the glandular cells in immediate ^contact with the surface of the blood-vessels ; an arrangement which does not exist in any other gland. We have been accustomed, therefore, to accord with the opinion of Dr. Thomas Williams*, that the limitary membrane of the bile-ducts is probably expanded over the whole of the parenchymatous portion of each lobule, moulding itself upon, and identifying itself with, the capsule or sheath of the vessels, and thus forming a sort of irregularly reticulated cavity, which may be described as the whole space occupied by the lobule, minus the series of passages containing the capillary plexus. The manner in which the lining membrane of the uterine sinuses with the cellular decidua are prolonged into the placenta, and reflected over the capillary tufts of the foetal vessels, so as to divide the whole cavity of the placenta into a series of irregularly shaped chambers, freely communicating with each other, into which the maternal blood is conveyed, will convey an idea of this method of viewing the disposition of parts in the liver ; the uterine sinuses representing the bile-ducts ; the cellated cavities of the placenta, corresponding with the spaces occupied by the cells of the hepatic parenchyma ; and the foetal vessels occupying\nFig. 317.\nBiliary plexus in human Liver.\nthe place of the capillary plexus from which the secretion is formed.\nThe observations recently published by Dr. Leidy harmonise precisely with the view promulgated by Mr. Kiernan, and seem to confirm the idea that here, as elsewhere, the hepatic cells are enclosed in a limitary membrane. \u201c The lobules are composed of an intertexture of biliary tubes (fig. 317.) ; and in the interspaces of the network the blood-vessels ramify and form among themselves an intricate anastomosis, the whole being intimately connected together by a combination of the white fibrous and the yellow elastic tissue. In\nFig. 3IS.\nBiliary plexus in human Liver.\nA small portion of the same section more highly magnified. The secreting cells are seen within the tubes ; and in the interspaces of the latter, the fibrous tissue is represented. (After Leidy.)\nstructure, the biliary tubes (figs. 318,319.) correspond with those of Invertebrata, consisting\nFig. 319.\nBiliary tubulus of human Liver.\nPortion of a biliary tube from a fresh human liver, very highly magnified. The secreting cells are seen to be polygonal from mutual pressure. {After Leidy.)\nTransverse section of a lobule of the human liver\u2019 highly magnified, showing the reticulate structure of the biliary tubes. In the centre of the figure is seen the hepatic vein cut across, and several small branches terminating in it. At the periphery are seen branches of the hepatic artery, vena port\u00e6, and hepatic duct. (After Leidy.)\n* Op. cit. p. 330.\nof cylinders of basement membrane, containing numerous secreting cells, and the only difference exists in the arrangement, the free tubes of the lower animals becoming anastomosed on forming an intertexture in the Ver-tebrata. The tubuli vary in size in an unimportant degree in different animals, and also in the same animal, being generally from two\nG G 2","page":451},{"file":"p0452.txt","language":"en","ocr_en":"452\nSECRETION.\nto two and a half times the diameter of the secreting cells. The tubes of one lobule are distinct from those of the neighbouring lobuli, or only communicate indirectly by means of the trunks or hepatic ducts, originating from the tubes, and lying in the interspaces of the lobuli. The secreting cells (fig. 320.) are irregularly angular or polygonal in form, from mutual pressure, and line the interior surface of the tubes. They vary in size in a moderate degree in different animals, and also in the same animal, appearing to depend upon certain conditions of the animal and liver.\u201d* We have ourselves verified these important observations to a certain point, not having been able to obtain a view of the regular and complete plexus of ducts figured and described by Dr. Leidy,but having satisfied ourselves that a system of canals, prolonged from the bile-ducts, exists in each lobule. The recently published observations of Dr. Natalis Guillot-f-are to the same effect. He has not been able, any more than ourselves, to distinguish membranous parietes around these canals ; and he considers that they are simply channelled out in the parenchyma of the liver, the particles of which form its sole borders. It appears probable to us, however, that these canals correspond to the spaces left in the centre of the biliary tubuli of insects, &c.;; and that the membranous walls, if they exist at all, would be found to invest the cells which immediately bound these passages.\nThe biliary cells of the Mammalia (fig. 320.) usually contain a certain number of adipose particles; their size and number, however, vary considerably according to the food of the animal, the amount of ex\u00e8rcise which it has been taking, and other circumstances. If an animal be very fat or well fed, especi-\nFig. 320.\nHepatic cells of human Liver.\na, three secreting cells of ordinary aspect; b, a secreting cell much more highly magnified, showing the central nucleus, granular particles, and oil globules ; c, four secreting cells from a human liver in a state of fatty degeneration, showing a great increase of oil globules. ( After Leidy.)\nally with farinaceous or oleaginous substances, the proportion of adipose particles is much greater than in an animal moderately fed and taking much exercise. The size of the globules varies from that of mere points, scarcely distinguishable from the granular contents of the cells but by their intense blackness, up to one-fourth of the diameter of the cell. The finely granular matter is the portion from which the colour of the cell is derived ; it seems to fill the space not occupied by the oil globules ; and it often obscures the nucleus, so that the latter cannot be distinguished until acetic acid is added, which makes the granular matter more transparent without affecting the nucleus.\nThe following are the dimensions of the hepatic cells in various animals, according to the measurements of Dr. Leidy (loc. cit.).\n\t\tLong Diam.\tShort Diam.\tNucleus.\n\t\tMillim.\tMiliira.\tMillim.\nCentipede (Julus impressus)\t-\t\u20220125\t\t\nTumble bug (Ateuchus volvens)\t-\t\u20220225\t\u20220125\t\nKatydid (Platyphyllum concavum) -\t-\tT3\t\u2014\t\u20220225\nHouse-fly (Musca domestica') -\t-\t\u202209\t\u202206\t\u20220225\nFlesh-fly (Musca carnaria)\t-\t-\t\u202209\t\u2014\t\u20220275\nCray-fish (Astacus affinis)\t-\t\u202206 to -02\t\u2014\t\u2022015\nSnail (Helix albolabris) -\t-\t\u202204 to -02\t\t\nSlug (Limax variegatus)\t-\t\u202206 to -03\t\t\nRock-fish (Labrax lineatus) -\t-\t\u20220275\t\t\nMinnow (Hydrargira ornata)\t-\t\u202202\t\u2022015\t\nCat-fish (Pimelodus catus)\t-\t\u20220275\t\t\nLizard (Triton niger)\t-\t-\t-\t-\t\u202203\t\u2014\t\u20220125\nFrog (Rana halecina)\t-\t-\t\u202203\t\u202202\t\u2022005 to -01\nTerrapin (Emys Terrapin)\t-\t\u202203\t\t\nSnake ( Tropinodotus sirtalis') -\t-\t\u202202 to *0275\t\t\nBoa (Roes constrictor)\t-\t-\t\u202203\t\u2014\t\u2022015\nDuck (Anas acuta')\t-\t-\t\u20220175 to \u201902\t\u2014\t\u2022006\nOwl (Strix brachyotos) -\t-\t-\t-\t\u2022015\t\u2014\t\u2022005\nChicken ( Gallus domesticus) -\t-\t\u2022016\t\t\nGround Squirrel (Sciurus striatus) -\t-\t\u20220175\t\t\nGray Squirrel (Sciurus Carolinensis)\t-\t\u2022015\t\t\nRabbit (Lepus Americanus) -\t-\t\u202203 to -015\t\u2014\t\u202201\nSloth (Bradypus tridactylus ) -\t-\t\u20220133\t\t\nLeopard (Felis leopardus)\t-\t\u20220125 to 015\t\t\nMonkey ( Simla\t?)\t-\t-\t\u2022015\t\t\nMan ------\t-\t\u202203 to *015\t\u202202\t\u2022009\n* See American Journal of the Medical Sciences, of injected liver, then to make as thin a slice of this Jan. 1848. Dr. Leidy does not specify the mode in as possible, and to examine this slice when restored which his preparations have been made; but we to its original condition by moisture, understand that his plan is to dry a small portion f Annales des Sciences Naturelles, Mars, 1848.","page":452},{"file":"p0453.txt","language":"en","ocr_en":"SECRETION.\n453\nWhen the foregoing facts are duly weighed, the conclusion seems irresistible, that the cells containing the biliary matter are the only invariable constituents of the hepatic apparatus ; and that the manner in which these cells are arranged, and brought into relation with the blood-vessels, may vary indefinitely without producing any change in the character of the product. Consequently we cannot but look upon the biliary cells as the essential portion of the secreting structure ; and we must, in like manner, consider their agency as the essential part of the secretory function.\nThe same result has been obtained in all other cases in which the character of the secreted product is such, that it can be detected, when in a finely divided state, by the assistance of the microscope. Thus Prof. Goodsir has shown* that the pigmentary matter of the \u201cink\u201d of the cuttle-fish is contained within the cells that line the ink-bag ; that the purple fluid secreted from the edge and internal surface of the mantle of Ianthina fragilis (which is supposed to have furnished the Tyrian dye) is contained within a layer of nucleated cells situated on the secreting surface ; and that a fluid resembling milk may be found in the cells contained within the ultimate follicles of the mammary gland in a lactating animal. We seem perfectly justified in concluding, therefore, that in cases where the transparency and freedom from colour of the secreted product prevent our distinguishing it in the cells of the organ by which it is eliminated (as in the case of the urine), it is nevertheless contained within them and eliminated by their agency.\nIt would probably be too much to affirm, that the elimination of the secretion always involves the continual exuviation of the cells, which are the instruments of the process. On the contrary, it seems probable that where the solid matter of the secretion bears but a small proportion to the liquid, and is in a state of perfect solution, the secreting cells ma}' be continually drawing in their peculiar pabulum on the side nearest to the capillary network, and may be as constantly allowing it to transude by the free surface, so as to permit its passage into the cavity of the tube or follicle,\u2014the cells themselves remaining attached to its walls, and continuing to perform this function for a considerable time. Such is probably the case with regard to the epithelial cells which line the tubuli of the kidney, and which eliminate the secretion of urine ; and those which line the tubes of the perspiratory glandule are probably as permanent.\nIn the case of cells, however, whose secretion contains a large quantity of solid matter, and especially where this is of an adipose character, it seems impossible to suppose that their contents can be given up, without the rupture or deliquescence of the cell-walls. This may take place either whilst the cells are yet in the follicles within which they were generated, or after they have been cas.t entire\n* Trans, of Royal Society of Edinburgh, 1842.\ninto the ducts, or have been even conveyed through them to their outlet. We have seen that in the biliary follicles of the Invertebrata, the discharged contents of secreting cells are usually to be met with, indicating that this rupture or deliquescence has taken place within the follicles ; and this is probably the fact in regard to the biliary cells in general. An extreme case of another kind is furnished by Mr. Harry Goodsir, in regard to the cells of an organ which is essentially one of secretion as to its structure, though its function has a different direction ; the peculiarity of this case being, that even after the complete exuviation of the cells, they retain so much of independent vitality, as to proceed in their own development to a stage much beyond that at which they were set free. The case referred to is that of the seminal secretion of the deca-podous crustaceans ; the cells of which, when thrown out of the caeca of the testis, are very immature, and undergo important changes in their progress along the tubuli of that gland. The final changes, however, whereby they are fitted for the fertilisation of the ova, only take place after they have been discharged from the male organs, and have been lodged in the spermotheca of the female.*\nNow in every case in which the secreted product can only be given up by the rupture or solution of the cell-wall, it is obvious that there must be a continual succession or new production of the secreting cells ; and a question naturally arises as to their origin and mode of development. Few facts are as yet known upon this subject. It may, however, be stated with some certainty, that, in many of the simpler glands at least, the follicle with its contained secreting cells was originally a single closed' cell, of which the secreting cells are the- progeny. This is the case with the Peyeriau glands, which are best known to us in this condition, but which afterwards open and discharge their contents into the intestinal canal. Dr. Allen Thomson has ascertained that the primitive condition of the gastric gland also is that of a closed vesicle ; and Henle has extended this view to the terminal follicles of the more complex secreting glands, which he considers to have originated in the same condition. The observations of Prof. Goodsir upon the testis of Sqaalus cornubicus show that this is the true account of the changes occurring in that organ ; the following stages being distinguishable in its structure, when it is in a condition of activity :\u20141st, Isolated nucleated cells attached to the side of the duct, and protruding as it were from its outer membrane (fig. 321. a). 2nd, A cell containing a few young cells grouped in a mass within it, the parent cell presenting itself more prominently on the side of the duct. 3d, A cell attached by a pedicle to the duct, the pedicle being tubular, and communicating with the duct ; the cell itself being pyriform, but closed and full of nucleated cells (b).\n* Anatomical and Pathological Observations, p. 39.\nG G 3","page":453},{"file":"p0454.txt","language":"en","ocr_en":"SECRETION.\n45 t\n4th, Cells larger than the last, assuming more of a globular form, still closed, full of nu-\nFig. 321.\nProgressive development of vesicles of testis of Squalus cornubicus.\na, portion of duct with a few nucleated cells, the primary or germinal cells of the future acini, attached to its walls ; b, c, d, e, f primary cells, or acini, in successive stages ; g, one of the secondary cells in an immature state ; h, a secondary cell elongated into a cylinder, each cell of its composite nucleus elongated into a spiral ; i, k, the spiral cells or spermatozoa free. (After Goodsir.)\ncleatecl cells, and situated more towards the surface of the lobe (c). 5th, The full sized vesicles situated at the surface of the lobe, with their contents in various stages of development (d, e, f). These vesicles are spherical and perfectly closed ; that part of the wall of each, which is attached to the hollow pedicle, forming a diaphragm across the passage, so that the vesicle has no communication with the ducts of the gland. The contained cells are at first spherical (g) ; but as the spermatozoa are gradually formed within them, they present a cylindrical form (h), and they are arranged within the vesicles in somewhat of a spiral manner (/). When the development has advanced to this stage, the diaphragms across the necks of the vesicles dissolve away or burst ; and the bundles of spermatozoa float along the ducts of the gland, some of them separating into individual filaments (i, k). Besides the bodies now described, Prof. Goodsir has observed what he considers to be vesicles which have discharged their contents, and which are in a state of atrophy (Jig. 322. a).\nThe testis of Squalus cornubicus, the functional history of which has been now given, is considered by Prof. Goodsir as a type of a number of glands, whose action takes place after the same manner ; and he lays down the following general facts, which he has ascertained in regard to glands of this order.\n\u201c 1st, The glandular parenchyma is in a\nconstant state of change, passing through stages of development, maturity, and atrophy.\n\u201c 2d. The state of change is contemporaneous with, and proportional to, the formation of the secretion, being rapid when the latter is profuse, and vice versa.\n\u201c 3d. The acinus is at first a single nucleated cell. From the nucleus of this cell others are produced. The parent-cell, however, does not dissolve away, but remains as a covering to the whole mass, and is appended to the extremity of the duct. Its cavity, therefore, as a consequence of its mode of development, has no communication with the duct. The original parent-cell begins to dissolve away, or to burst into the duct, at a period when its contents have attained their full maturity. This period varies in different glands, according to a law or laws peculiar to each of them.\n\u201c 4. The secretion of a gland is not the product of the parent-cell of the acinus, but of its included mass of cells.\u201d *\nAn ideal representation of these successive changes is given in fig. 322. At b is seen a\nFig. 322.\nIdeal representation of changes occurring in vesicular glands.\na, a bunch of acini in various states of development, maturity, and atrophy ; b, c, d, are diagrams, arranged so as to illustrate the intimate nature of the changes which occur in vesicular glands when in a state of functional activity. ( After Goodsir. )\nportion of gland with two acini ; one of them being a simple primary cell, the other being in a state of development, its nucleus producing young cells. At c, both acini are advancing ; the second has almost reached maturity. At d the second acinus is ready to pour out its contents, and the first to take its place ; and at e, the second acinus is thrown in a state of atrophy, whilst the first is become fully matured.\nThere is another set of glands, in which the follicles remain persistent for a much longer period, and continue to produce many successive generations of secreting cells ; of these, the liver of the Crustacea may be taken as the type. From the appearances presented by these follicles, which have been already figured and detailed (fig. 312.), it seems fair to conclude, that the development of these cells\n* Anatomical and Pathological Observations, p. 30.","page":454},{"file":"p0455.txt","language":"en","ocr_en":"SECRETION.\n455\ntakes place from the c\u00e6cal extremities ; and Prof. Goodsir considers that they originate in a \u201c germinal spot,\u201d which is the persistent nucleus of the parent cell, whose enlargement and connection with the gland forms the follicle. Growth in glands of this kind is regulated, according to him, by the following laws : \u2014\n\u201c 1st. Each follicle is virtually permanent, but actually in a constant state of development and growth.\n\u201c 2d. This growth is contemporaneous with the function of the gland ; that function being merely a part of the growth, and a consequence of the circumstances under which it occurs.\n\u201c 3d. The vital action of some follicles is continuous, the germinal spot in each never ceasing to develope nucleated cells, which take on the action of, and become, primary secreting cells, as they advance along the follicle. The action of other follicles is periodical.\n\u201c 4th. The wall, or germinal membrane, of the follicle is also (probably) in a state of progressive growth, acquiring additions to its length at the blind extremity, and becoming absorbed at its attached extremity. A progressive growth of this kind would account for the steady advance of its attached contents, and would also place the wall of the follicle in the same category with the primary vesicle, germinal membrane, or wall of the acinus, in the vesicular glands.\n\u201c 5th. The primary secreting cells of the follicle are not always isolated. They are sometimes arranged in groups ; and when they are so, each group is enclosed within its parent-cell, the group of cells advancing in development according to its position in the follicle, but never exceeding a particular size in each follicle.\u201d*\nProf. Goodsir further expresses the opinion, that there is an order of glands with very much elongated ducts, which do not possess \u201c germinal spots \u201d in particular situations, but in which these spots are diffused more uniformly over the whole internal surface of the tubes. To this order he refers the kidney in Man and the higher Vertebrata.\nWe have thought it right to give Prof. Goodsir\u2019s statements in full, as being in the main unquestionably correct ; but we must express our own doubts as to that part of the doctrine which relates to the production of the secreting cells from distinct \u201c germinal centres.\u201d We have examined a great number of membranes bearing an epithelial covering, without being able to discern these ; and our own impression is, that the membrane itself is in a continual state of change, deriving from the blood-vessel, on the one side, the elements of the new growth, and yielding these up on the other.\nOf the first development of secreting structures, a partial account was formerly given (see Gland) ; and as this is on the whole in\n* Op. cit. p. 31.\nconformity with our present views, it is only requisite to add here the principal facts, ascertained by microscopic research since that article was written.\nThe \u201cplastic mass\u201d of which the entire gland consists in its early condition, is now known to be composed of nucleated cells, which appear to be the parent-cells within which the true secreting cells are afterwards to be formed ; these parent-cells themselves becoming the vesicles or follicles of the gland, by the establishment of communications between their cavities and the branches of the duct. It seems probable that some of the original component cells of the gland coalesce or break down altogether, so as to form the smaller ducts, the development of which has been observed to be quite independent of the protrusion of the principal duct, and of its primary branches, from the cavity of which it is a diverticulum. These last are properly intercellular passages ; which, as Prof. Good-sir justly observes, \u201c is an important consideration, inasmuch as it ranges them in the same category with the intercellular passages and secreting receptacles of vegetables.\u201d\nSources of the demand for the secreting function.\u2014We must now consider in more detail, the causes which render the performance of this function essential to the active existence of every living being.\n1.\tIn the first place, nearly all the solids and fluids of the animal body are liable to continual decomposition and decay, in virtue of their peculiar chemical composition. That the living state antagonises this decay, and that decomposition can only take place after death, is a doctrine which long held undisputed sway in physiological science, but which is now generally admitted to be completely untenable. The resistance to decay which living organised structures present, is rather apparent than real; for it only continues so long as the circulating current continues to pass through or near them, carrying off the products of incipient decomposition, and replacing these by matter that is newly organised.\n2.\tIn the second place, a continual decomposition and decay of an organised fabric is involved in its mere vegetative existence. For every portion of it has an individual and independent life, and a limited duration of its own: each part, like the simple isolated cell of the lowest Cryptogamia, grows from a germ, arrives at maturity, and finally dies and decays ; its debris being directly cast off, if the organ be external ; but being taken again into the current of the circulation, to be eliminated by another channel, if the part have no direct communication with the surface of the body.* Perhaps the most obvious example of this general fact is presented to us in the vegetable\n* The author believes that he may claim the credit of having been the first to enunciate this doctrine in definite terms, and as more than a mere hypothesis. (See Mr. Paget\u2019s Lectures on Nutrition, &c. Medical Gazette, 1847.)\nG G 4","page":455},{"file":"p0456.txt","language":"en","ocr_en":"456\nSECRETION.\neconomy. The cells of the woody stem have a long and almost indefinite duration, especially after they have become consolidated by the filling-up of their cavities with resinous or sclerogenous secretions ; but those of the leaves, which are much more actively concerned in the vital operations, have a short and limited term of existence. The \u201c fall of the leaf\u201d is not the cause of the death and decay of the organ, but its result ; for the decomposition of its tissues is already far advanced, when its detachment occurs : \u2014 its functions have been fulfilled ; its term of life is expired ; and it is cast off, to be replaced by a new development of cellular parenchyma, which in its turn will discharge the same important function, that of preparing the materials for the growth of the more permanent parts of the fabric. This kind of passive change is more constantly going on in the animal body than is usually supposed, especially during the period of its growth and increase. A goad illustration is afforded by the deciduous or milk teeth. \u201c We trace each of these developed from its germ, and, in the course of its own development, separating a portion of itself to be the germ of its successor ; then each, having attained its due perfection, retains for a time its perfect state, and still lives though it does not grow. But at length, coincidently, not consequently, as the new tooth comes, the deciduous tooth dies ; or rather, its crown dies, and is cast out like a dead hair; while its fang with the bony sheathing, and the vascular and nervous pulp, degenerates, and is absorbed. It is here especially to be observed, that the degeneration is accompanied by some spontaneous decomposition of the fang, for it could not be absorbed unless it was first so changed as to be soluble. And it is degeneration, not death, which precedes its removal; for when a tooth fang really dies, as that of the second tooth does in old age, then it is not absorbed, but is cast out entire, as a dead part. Such, or nearly such, it seems almost certain, is the process of assimilation everywhere ; these may be taken as types of what occurs in other parts, for these are parts of complex organic structure and composition ; and the teeth-pulps, which are absorbed as well as the fangs, are very vascular and sensitive, and therefore, we may be nearly sure, are subject to only the same laws as prevail in all equally organised parts.\u201d* All the epidermic and epithelial structures, including the secretory substance of glands, are continually undergoing the same change, by the exuviation of the old cells when their term of life is accomplished, and by the production of new ones ; the durability being different according to the particular endowments of the part, but also varying with changes in the supply of blood, which increase or decrease its vital activity. Generally speaking, those parts which live most slowly are those of which the diration is the greatest, and in which there if con-\nsequently the least frequent change. Of the exuviation of epidermic structures en masse \u2014 a process altogether comparable to the fall of the leaf \u2014we have striking examples in the entire desquamation of serpents, the moulting of the plumage in birds, and the shedding of the hair in the mammalia ; and in the shedding of the antlers of the stag, we have an example of the exuviation of a highly organised and vascular part, which periodically dies, and which, being external, is cast off entire. \u201c What means all this,\u201d says Mr. Paget *, \u201c but that these organs have their severally appointed times, degenerate, die, are cast away, and in due time are replaced by others, which in their turn are to be developed to perfection, to live their life in the mature state, and in their turn to be cast off? \u201d There can be little doubt that a similar change is continually taking place, with more or less activity, in every part of the internal structure ; the products of decay, however, not being at once thrown off, because there is no direct means of getting rid of them ; but being received back into the current of the circulation, to be eliminated by instruments expressly provided for that purpose.\nNow, this interstitial change must take place constantly, during the whole life of the entire structure ; but its activity varies according to certain conditions to which the fabric is subjected. One of the most important of these conditions is heat. It is well known that the tendency to decomposition, which is characteristic of organic compounds, is dependent upon the heat to which they are subjected : thus a compound which passes rapidly into decomposition at 100\u00b0, shall be much less prone to decay at 60\u00b0, and shall be permanent at 32\u00b0. And again, the vital activity of the several parts of the organised fabric is so dependent upon the same stimulus, that a very moderate depression of temperature serves to reduce it, or even to suspend it altogether. Now, when the activity of a part is thus reduced, so that it lives more slowly, its duration is proportionally increased, and interstitial change and renewal are scarcely required. We have obvious examples of this in the activity of all the functions in warmblooded as compared with cold-blooded animals ; in the superior energy of all the vital operations of birds, whose temperature is 10\u00b0 or 12\u00b0 above that of the Mammalia ; and, on the other hand, in the torpor of cold-blooded animals, and of hyhernating Mammalia, when the temperature of their bodies is depressed nearly to the freezing point. In the state of greatest .activity, all parts of the body live fast ; their duration is proportionally diminished ; interstitial death and decomposition are continually taking place ; the results of this decomposition have to be got rid of from the body ; and a corresponding demand is set up for nutrient materials, to be applied to the renovation of the structure. On the other hand, a reduction of temperature, which di-\nPaget, Lectures on Nutrition, &c.\n* Loc. cit.","page":456},{"file":"p0457.txt","language":"en","ocr_en":"SECRETION.\n457\n\u2022ninishes the vital activity of the living tissues, tends also to increase their duration ; and this not merely by causing them to live more slowly, but by obstructing the spontaneous decomposition of their organic constituents. This reduction may be carried to such an extent as, on the one hand, to suspend all vital action, whilst, on the other, it prevents decomposition ; so that the body remains in a state of dormant vitality, undergoing no change whatever for an indefinite period, but ready for a renewal of its vital activity whenever an increase of temperature shall awaken its slumbering energies. (See Life.) The more nearly a living structure is reduced to this condition, the less interstitial change does it undergo ; the less nutriment, therefore, does it require ; and the less effete matter is there to be thrown off.\nThe activity of that spontaneous interstitial change, which takes place as a part of the mere vegetative life of the animal organism, further varies in accordance with the period of life of the fabric taken as a whole. Thus all the tissues, even those most consolidated, are undergoing continual changes in the young animal, in which the processes of decay and renewal go on much faster than in the adult ; and in the adult, than in the aged person. Thus we have seen that the duration of the deciduous teeth is very limited ; whilst that of the permanent teeth may be coeval with the life of the entire animal, little or no interstitial change taking place in them during the whole ofthat period. So also the component parts of the bony structure, which in the adult are almost permanent, and in the aged become so remarkably solidified that little or no interstitial change can take place in them, are liable in the growing child to continual decomposition ; no part of the substance of a long bone having any permanence, but the interior layers of the shaft being removed (by absorj)tion, it is commonly said, but the absorption being probably in reality preceded by de-genei'ation), so as to enlarge the medullary cavity, in proportion as new layers are formed on the external surface. This may be partly accounted for by the imperfect degree in which, so long as the entire organism is undergoing rapid increase, the normal structure is developed in any one portion of it ; for as the degree of consolidation is less, the tendency to decay wili be greater. But this explanation is not in itself sufficient, and we must be content, for the present, to regard it as a general law, that, with the advance of life, the duration of the individual components of the organism increases, whilst their functional activity diminishes. (See Age.)\n3.\tBut, in the third place, the exercise of the Animal functions seems to be essentially destructive of the structures which are their instruments ; every operation of the muscular and nervous systems appearing to require, as its necessary condition, a disintegration of a certain portion of their tissues, probably by the union of their elements with the oxygen supplied by arterial blood. The duration of\nthe existence of these tissues may be clearly shown to vary inversely with the use that is made of them, being less as their functional activity is greater. Hence, when an animal is very inactive, it requires but very little nutrition ; if in moderate activity, there is a moderate demand for food ; but if its nervous and muscular energy be frequently and powerfully called into exercise, the supply of aliment must be increased, in order to maintain the vigour of the system. In like manner, the amount of the effete matters, which result from the disintegration and decay of those tissues, must increase with their activity, and diminish in proportion to their freedom from exertion.\n4.\tA necessity for the secreting process may further arise within the system from the ingestion of superfluous aliment. This would not be the case, if the amount of food prepared by the digestive process, and taken up by absorption into the current of the circulation, were always strictly proportional to the demand for nutriment created by the wants of the system. There can be no doubt that almost every individual who is not restrained by considerations of economy, or by fear of unpleasant consequences, from indulging his natural appetite, really takes in more fiiod than the wants of his system absolutely require ; and all that is not appropriated to the reparation of the waste, or to the increase in the weight of the body, must be thrown off by the excreting organs, without having ever been converted into organised tissue. The superfluous portion of the non-azotised constituents of the food may be deposited as fat in those individuals who have a disposition to the production of adipose tissue ; but the azotised constituents cannot be applied in like manner to the unlimited increase of the muscular and other tissues ; and that which is not speedily converted into organisable material, and drawn off from the blood by conversion into organised tissue, would accumulate injuriously in the circulating current, and would taint it by decomposition, if it were not continually removed by the excreting processes.\n5.\tAgain, it cannot be deemed improbable that the changes which the crude aliment undergoes, from the time of its first reception into the absorbents and blood-vessels, to that of its conversion into organised tissues and into the materials of secretions eliminated for some special purpose in the economy, involve the liberation of many products, of which the elements are superfluous, and therefore injurious to the system if retained within it. The condition of organic chemistry, however, is not at present such as to admit of anything being advanced with certainty under this head.\nFrom these various sources, then, a large amount of effete matter is being continually received back from the tissues into the current of the circulation, or is generated in the blood by the changes to which it is itself subject ; and it is one great object of the secreting apparatus, to free that fluid of the products which would rapidly accumulate in it, but for the","page":457},{"file":"p0458.txt","language":"en","ocr_en":"458\nSECRETION.\nprovision which is thus made for their removal.\nThe first product of the decay of all organised structures is carbonic acid ; and this is the one which is most constantly and rapidly accumulating in the system, and the retention of which, therefore, within the body, is the most injurious. Accordingly, we find two organs, the lungs and the skin, specially destined to remove it ; and their action is so contrived, that whilst eliminating a noxious product, they shall be subservient to the introduction into the system of the vivifying element, oxygen, without a continued supply of which the animal functions cannot be long kept in activity, nor the heat of the body sustained.\nThe skin, again, is one of the organs for the removal of the superfluous water from the body ; and the exhalation from its surface, the amount of which varies with the degree of external heat, serves the additional purpose of keeping down the temperature to its normal standard. The lungs also regularly throw off a considerable quantity of water, of which the amount is but little subject to variation, and of which some portion may have been actually generated in the blood by the union of hydrogen and oxygen. And the kidneys, the structure of which is beautifully adapted to eliminate the superfluous fluid by simple mechanical transudation, draw off the residue ; the amount of water which they remove being the complement of that exhaled by the skin.\nAll azotised substances have a tendency, during their decomposition, to throw off nitrogen ; and in the animal body this element is for the most part eliminated by the kidneys, entering largely into the composition of the urinary secretion. Thus we find urea to contain a larger proportion of nitrogen than exists in any other organic compound ; and uric acid, hippuric acid, kreatine and kreatinine, and other compounds, which are characteristic elements of this secretion in different animals, are all rich in nitrogen. But it is not only by the kidneys that azotised substances are' thrown off, for the solid matter exuded from the skin closely corresponds in composition with that of the urinary secretion ; and urea has been detected in it.\nThe biliary secretion is peculiarly rich in hydrocarbon, and may probably be regarded as the complement of that of the kidneys ; it having been shown by Liebig, that if the empirical formulai for the bile and urine be added together, the result comes very near to the empirical formula for blood. Of this secretion, a part is certainly destined to be immediately carried oft'through the intestinal canal ; but another part seems to be re-absorbed, in combination with the fatty matters of the food, and to be subsequently'thrown off by the respiratory process. What proportion is applied to each purpose cannot be definitely stated, and probably varies much with circumstances.\nBut besides the metamorphosis ot the or-\nganised tissues, and of the organic elements of the blood, into the definite (generally crystalline) compounds, which are the characteristic elements of the secretions already mentioned, it would seem that a portion of the effete matters take on a 'putrescent state ; and that for the elimination of these a special and most appropriate apparatus is provided, namely, the extensive system of glandul\u00e6 in the wall of the intestinal canal. As this point has been much less attended to than its importance deserves, it seems desirable to dwell upon it here in some detail. It has been too much the custom to regard the fiecal evacuations as little else than the indigestible residue of the food, mingled with portions of the biliary and pancreatic secretions ; whereas we think that a little consideration will show, that the peculiarly fiecal matter is a real excretion, which must have been eliminated from the blood by the intestinal glandul\u00e6. The undigested residue of the food may form a greater or a smaller proportion of the bulk of the evacuation, according to the nature of the ingesta and the completeness of the digestive process. When the alimentary canal is in an irritable state, and the aliment is hurried through it without time being allowed for the proper action of the gastric secretions, a considerable part of it may be recovered from the faeces in an almost unchanged condition. It has been found that even starch vesicles, if not ruptured by the masticating process, or by the heat employed in the preparation of the food, resist the digestive process so completely -as not to give up their contents ; being readily detectible in the faeces, in an entire state, by the assistance of the microscope. Further, there is no evidence whatever, that the undigested residue of the food could acquire the faecal character, during the short period which suffices in the state of health for its transmission along the alimentary canal ; and there is every reason to believe the contrary, since the substances which resist the action of the gastric solvent are precisely those which have the least tendency to this kind of decomposition. Moreover, in purely Carnivorous animals, and in Man when he adopts the same diet, faecal matter is still voided, though in smaller quantity than in Herbivora. The case is still stronger in regard to sucking animals ; since the milk by which they are supported is pure nutriment, of which no part can be supposed to pass directly into the faeces. The continued evacuation of faecal matter when little or no food has been taken in, the large quantity brought off by purgative medicines after the bowels have been completely emptied of their solid contents, and the colliquative diarrhoea which so frequently occurs at the close of exhausting diseases and previously to death by starvation, are so many obvious confirmations of the same view. And Dr. Williams* has pointed out many pathological phenomena, which indicate that the inflammation and ul-\n* Principles of Medicine, 2d ed. p. 248. note.","page":458},{"file":"p0459.txt","language":"en","ocr_en":"SECRETION.\t459\nceration of the intestinal glandul\u00e6, which is so frequent a complication of fevers and of other diseases induced by the presence of a morbid poison in the blood, results from the continued operation, upon their own structure, of the noxious matter which these glandul\u00e6 are endeavouring to eliminate from the system. This view has derived important confirmation from experiments recently made by Prof. Liebig ; these having indicated that the substances to which the f\u00e6ces owe their peculiar fcetor may be artificially produced by the imperfect oxidation of albuminous compounds.* The immense relief frequently given by an attack of diarrhoea, which spontaneously eliminates morbific matters that were operating prejudicially on the system, and the corresponding effects of mild purgatives, which excite the secreting action of these glandul\u00e6, furnish additional evidence, if such be required, to the same effect. It is obviously important in a therapeutic point of view, that definite ideas should be entertained on this subject ; and although it may be difficult to obtain positive proof of the position here advanced,\u2014 that it is the special function of the glandul\u00e6 of the lower part of the small intestines, and at the upper part of the large, to eliminate from the blood the putrescent matter which results from the disintegration of the tissues,\u2014it will scarely be denied that a strong probability has been established by the foregoing evidence, in favour of such a view.\nThe interruption of any of these excreting processes, by causing an accumulation of effete matters in the blood, occasions speedy death (see Excretion); and Dr. Marshall Hall was perfectly correct in affirmingf, that the functions of egestion are more immediately necessary to the maintenance of life than those of ingestion. For whilst most animals may live for a considerable time without food, and many without oxygen, there are none which are not speedily killed (unless previously reduced to a state of torpidity) by the complete suspension of the excretory operations.\nIn all the cases hitherto considered, the necessity for the secreting function arises out of the changes which are continually taking place in the system at large, and which tend to produce an injurious effect upon the character of the blood. We have seen, however, that even the act of liberation of effete or superfluous matters is frequently made to answer some ulterior purpose in the economy ; and we are thus led to notice the other class of secretions, in which this ulterior purpose appears to be the principal, if not the sole, object of their separation. The variety of these, however, is so great, and their uses are so different, that no general statement can be made regarding them. It must suffice to refer to a few examples, such as will show their importance in the economy of the different animals which form them. The secretion of tears for the cleansing and lubrication of the\n* Animal Chemistry, 3d ed. p. 154.\nf Gulstonian Lectures, 1842.\nsurface of the eye ; the salivary, gastric, and pancreatic secretions for the reduction and solution of the food ; the mammary secretion for the nutrition of the offspring; the sebaceous secretions for the lubrication of the skin ; the mucous secretions for the protection of the mucous membranes ; the poisonous secretions of certain serpents, insects, &c. ; the glutinous secretion with which the silkworm weaves its cocoon and the spider its web ; the pigmentary secretion of the cuttle-fish ; the colouring matter secreted by the mantle of many of the mollusca for imparting various hues to their shells ; the strongly odorous secretions of many animals, which seem generally attractive to those of their own kind, but repulsive to others ; together with many others that might be cited, are sufficient to indicate that the formation of even a very small amount of some peculiar product may be essential to the wellbeing of the animal which furnishes it ; by contributing to the due performance of one or more of its vital functions, or by the protection it affords to some important organ.\nExistence of the elements of secretions in the blood. \u2014 The chemical proofs which have been recently obtained of the presence of the characteristic elements of certain secreted fluids in healthy blood, have afforded the most complete evidence of that which was previously highly probable, namely, that the office of the secreting organs is more that of selection and separation than that of conversion. The proof is most complete and satis-factorj' in regard to the chief elements of the urinary secretion ; but inferential evidence scarcely less conclusive exists with regard to several other substances.\nThe presence of urea in the blood was first clearly shown by Pr\u00e9vost and Dumas *, who found that when the functions of the kidneys were destroyed, either by the extirpation of those organs, or by ligature of the renal arteries, urea could be detected in the circulating fluids after a short period. Similar results have been obtained by other experimenters ; and pathological observation, in cases where the normal secretion has been suspended or greatly diminished (as in the advanced stages of Bright\u2019s disease), has equally shown that under such circumstances the presence of urea manifests itself in the blood when duly analysed.f An interesting case has lately been put on record by Dr. Shearman, in which the secretion of true urine being temporarily suspended, in consequence of accident (a watery fluid, containing neither urea, uric acid, nor the urates, being all that was passed for some days), urea was obtained in considerable quantity from the serum of blood drawn from the arm. J It would be difficult to explain such facts in any other way, than by supposing that urea is constantly being generated in the system, and\n* Annales de Chimie, tom. xxiii.\nt See Christison in Edinb. Med. and Surer. Journ. 1829.\nX Edinb. Monthly Journal, March, 1848.","page":459},{"file":"p0460.txt","language":"en","ocr_en":"460\nSECRETION.\nbeing received into the circulating current ; that being eliminated by the kidneys, in the state of health, as fast as it is formed, it has no time to accumulate in the blood ; but that when such elimination is checked or diminished, whilst its formation continues, the minute quantity originally present gradually increases, so as at last to become easily de-tectible by chemical processes. However probable such an explanation might be felt to be, it is yet satisfactory to find it confirmed by direct experiment.* Simon and Marchand some time since obtained satisfactory evidence of the presence of urea in the healthy blood of the cow ; and Dr. Garrod has lately succeeded in obtaining urea from the serum of healthy human blood. The amount, as might be anticipated, was very small, only l-200th of a grain of urea being procurable from 1000 grains of serum, j-\nThe pre-existence of uric acid in the blood might in like manner be inferred from the well-known fact of its deposition in gouty concretions : this inference, also, has been confirmed by Dr. Garrod, who has discovered uric acid in the blood of gouty subjects. It might be not unreasonably asserted, however, that the presence of uric acid in the blood is the result of a disordered condition of the system generally ; and it is hence satisfactory to find that in this case also Dr. Garrod has succeeded in obtaining the substance itself from healthy blood. He states that the amount seems liable to considerable variation, and to have some relation to the period that has elapsed since food was last taken, being least where this was longest : thus in one instance, where food had not been taken for twenty-four hours, 1000 grains of serum yielded only 2-1000th s of a grain of uric acid ; whilst a similar quantity of serum from the blood of other healthy subjects yielded 7-1000ths; and alike amount of serum from the blood of a man of full habit, but otherwise healthy, yielded 37-1000ths of a grain of uric acid.\nOf hippuric acid, which exists in small quantity in human urine, but in much larger amount in the urine of herbivorous animals, Dr. Garrod states (loc. cit.) that he thinks he has detected traces in the blood.\nThere can be no reasonable doubt that kreatine and kreatinine are normal elements of healthy blood, since they are constituents of the \u201cjuice of flesh,\u201d which seems to be the result of the disintegration of the muscular tissue, and must be taken into the circulating current to be conveyed from the muscles into the urine, where we again meet with these substances.\nIn like manner it is probable that lactic acid\n* Dr. Prout states ( On Stomach and Renal Diseases, 5th ed. p. 531. note), that when engaged in examining the blood in the year 1816, he found urea (or a substance having most of its properties) in that fluid ; but not crediting the fact, and thinking it might be accidental, he did not pursue the enquiry, though he made a memorandum of the circumstance.\nf Lancet, July 8. 1818.\nis normally present in the blood in very minute proportion ; for it abounds in the juice of flesh, and must be taken into the current of the circulation, in order to be eliminated from the body. In the healthy state it seems to be eliminated through the respiratory organs as fast as it is generated; being converted by oxidation into carbonic acid and water. It was formerly supposed to be a normal constituent of the urine; but it has been clearly proved by Liebig not to have a real existence there. Even when lactate of potash has been introduced by the stomach, the potash is thrown out by the kidneys in combination with other acids, the lactic acid not being eliminated in the urine, but passed off through the lungs. In certain diseased states of the system, however, lactic acid unquestionably presents itself in the gastric, urinary, and cutaneous secretions ; and as it has been shown to be one of the results of the disintegration of the muscular tissue, its pre-existence in the blood cannot be reasonably doubted.\nThe less definite nature of the constituents of bile prevents them from being as certainly recognised in the blood as those of urine have been ; nevertheless, the evidence of their preexistence in the circulating fluids is sufficiently clear. Thus cholestenne may be obtained from the serum of the blood by an analytical process of no great complexity ; and its presence there is also manifested by its occasional deposit, as a result of diseased action, in other parts of the body, especially in the fluids of local dropsies, as hydrocele, ovarian dropsy, &c. Again, the colouring matter of the bile seems to be nearly identical with certain normal elements of the blood, since the hue exhibited by a departing ecchymosis is identical with the characteristic colour of bile. In cases of jaundice, the presence of the colouring matter in the blood is often made evident, not merely by the communication of its peculiar hue to the several tissues and secretions of the body, but also by the tint visible in the serum of the blood itself. It would seem probable, however, that in many of these cases there has been an actual re-absorption of the biliary matter subsequently to its elimination by the liver, as a consequence of obstruction to its exit by the gall duct. But in the most severe and rapidly fatal cases of jaundice, as pointed out by Dr. Alison*, the secreting process has never taken place, and the colouring matter must then have been generated in the blood itself. Neither cholesterine, nor the colouring matter of bile, seem to exert the poisonous influence on the nervous system which is manifested in the cases alluded to ; and it is probable that this must proceed from the accumulation of the peculiar organic constituent of the bile. As the precise nature of this, however, is still a matter of discussion amongst chemists, we cannot be surprised that it has not yet been obtained by analysis from the blood.\n* Edinb. Med and Surg. Journ. vol. xliv.","page":460},{"file":"p0461.txt","language":"en","ocr_en":"461\nSECRETION.\nThe proof that the constituents of the milk pre-exist in the blood, is rather inferential than direct. That the caseine (although so like the albumen of the blood that we might imagine it to be a mere modification of it, effected in the act of secretion) is, in reality, specially prepared in the circulating current, would appear from the fact that, during pregnancy, a substance, kiestein, having a close relation to it, is eliminated by the urine, and that this substance disappears from the urine within a few days after parturition, the mammary secretion being then fairly established. Perhaps, however, the most remarkable evidence to the same effect is afforded by cases of metastasis of the mammary secretion, of which an account will be presently given ; and on the same kind of evidence rests the proof of the pre-existence of the other characteristic elements of the mammary secretion in the blood.\nWith regard, however, to the elements of other secretions, the evidence is less clear as to the state in which they exist previously to their elimination by the secreting apparatus. The fact would appear to be, however, that the solid constituents of most of them are little else than constituents of the blood itself, either pure or but slightly altered. Thus in the lachrymal fluid, the saliva, the gastric and pancreatic juices, and the serous fluid of areolar tissue and of serous and synovial membranes, we find little else than saline matters, which are normal constituents of the serum of the blood, with one or more organic compounds, that seem like albumen in a state of change. The repression of these secretions does not produce any deleterious effect upon the general system, otherwise than as impairing or preventing the performance of the function to which they are subservient; whence it may be inferred, that the selection of the secreted products from the blood is made in these cases, not for the sake of purifying the circulating fluid from any matter that would be noxious if retained, but merely for some minor purposes in the economy, to which these simple fluids are adequate.\nMetastasis of secretion. \u2014 Although the number and variety of the secretions become greater in proportion to the increased complexity of the nutritive processes in the higher classes, and although each appears as if it could be formed by its own organ alone, yet we may observe, even in the highest animals, some traces of the community of function which characterises the general surface of the lowest. It has been shown that, although the products of secretion are so different, the elementary structure of all glands is the same; that wherever there is afree secreting surface it may be regarded as an extension of the general envelope of the body, or of the reflexion of it which lines the digestive cavity ; that its epithelium is continuous with the epidermis of the integument, or with the epithelium of the mucous membrane from which it is prolonged ; and that the peculiar principles of\nthe secreted products pre-exist in the blood, in a form at least closely allied to that which they assume after their separation. Now, it may be stated as a general law in physiology, that in cases where the different functions are highly specialised (that is, where every one has its special and distinct organ for its own purpose alone), the general structure retains, more or less, the primitive community of function which characterised it in the lowest grade of development.* Thus, although the functions of absorption and respiration have special organs provided for them in the higher animals, they are not altogether restricted to these, but may be performed in part by the general surface, which (although the special organ for exhalation) permits the passage of fluid into the interior of the system, and allows the interchange of gases between the blood and the air. In the same manner, we find that the functions of secretion being equally performed in the lowest animals by the whole surface, whilst in the highest there is a complicated apparatus of glandular organs, to each of which some special division of the function is assigned, either the general muco-cutaneous surface, or some one of its subdivisions or prolongations, is able to take on in some degree the function of another gland whose functions may be suspended. This truth was well known to Haller, who asserted that almost all secretions may, under the influence of disease, be formed by each and every secreting organ.f This statement, however, needs to be received with some limitation, and it would be probably safest to restrict it to the excretions, whose elements pre-exist in the blood, and accumulate there when the elimination of them by their natural channel is suspended. We shall now consider some of the more remarkable examples of the metastasis of secretion.\nIt seems to be established by a great mass of observations, that urine, or a fluid presenting its essential characters, may pass off by the mucous membrane of the intestinal canal, by the salivary, lachrymal, and mammary glands, by the testes, by the ears, nose, and navel, by parts of the ordinary cutaneous surface, and even by serous membranes, such as the arachnoid lining the ventricles of the brain, the pleura, and the peritoneum. A considerable number of such cases was collected by Haller J : many more were brought together by Nysten $ ; more recently Bur-dach has furnished a full summary of the most important phenomena of the kind [| ; and Dr. Laycock has compiled a valuable summary of cases of urinary metastasis occurring as complications of hysteria.^] The following table\n* See the author\u2019s \u201c Principles of General and Comparative Physiology,\u201d 2d ed. \u00a7 243.\nf Elementa Physiologi\u00e6, tom. ii. p. 369.\nX Ibid. p. 370.\n\u00a7 Recherches de Physiologie et de Chimie pathologique, p. 265.\nIl Trait\u00e9 de Physiologie (Jourdan\u2019s Translation), vol. viii. p. 248, et seq.\nf Edinb. Med. and Surg. Journ. 1838.","page":461},{"file":"p0462.txt","language":"en","ocr_en":"462\tSECRETION.\nof cases referred to by the last of these authors of the different forms of this curious affec-will give some idea of the relative frequency tion : \u2014\nY omit.\tStool.\tEars.\tEyes.\tSaliva.\tNose.\tManim\u00e6.\tNavel.\tSkin.\tTotal.\n33\t20\t4\t4\t5\t3\t4\t34\t17\t124\nIt is to be borne in mind, however, that cases of hysterical ischuria are frequently complicated with that strange moral perversion, which leads to the most persevering and ingenious attempts at deceit ; and there can be little doubt that a good many of the instances on record, especially of urinous vomiting, are by no means veritable examples of metastasis. The proofs of the fact we are seeking to establish are, therefore, much more satisfactory when drawn from experiments upon animals, or from pathological observations, about which, from their very nature, there can be no mistake.\nThus Mayer* found that when the two kidneys were extirpated in the guinea-pig, the cavities of the peritoneum and the pleura, the ventricles of the brain, the stomach, and the intestinal canal, contained a brownish liquid having the odour of urine ; that the tears exhaled the same odour; that the gall-bladder contained a brownish liquid not resembling bile ; and that the testicles, the epididymis, the vasa deferentia, and the vesicul\u00e6 s\u00e9minales, were gorged with a liquid perfectly similar to urine. Chirac and Helvetius are quoted by Haller as having tied the renal arteries in dogs, and having then remarked that a urinous fluid was passed off from the stomach by vomiting. A remarkable case is quoted by Nysten from Zeviani, in which a young woman having received an incised wound on the external genitals, which would not heal, the urine gradually became more scanty,, and at last none could be passed even with the assistance of the catheter ; at last dropsy supervened, with sweats of a urinous odour, and vomiting of a urinous fluid, which continued daily for thirty-three years. On post-mortem examination, the kidneys were found disorganised, the right ureter entirely obliterated and the left nearly so, and the bladder contracted to the size of a pigeon\u2019s egg. In some other instances, the urine appears to have been secreted, and then re-ab-sorbed in consequence of some obstruction to its exit through the urinary passages. Thus Nysten quotes from Wrisberg a case in which, the urethra having been partially obstructed for ten years by an enlarged prostate, the bladder was so distended as to contain ten pounds of urine ; and the serosity of the pericardium and of the vesicles of the brain exhaled a urinous odour. He cites other instances in which the presence of calculi in the bladder prevented the due discharge of the secretion ; and in which a urinous liquid was ejected from the stomach by vomiting, or was\n* Zeitschrift f\u00fcr Physiologie, tom. ii. p. 270.\ndischarged by stool. A still more remarkable case is recorded, of a girl born without either anus or external genitals, who nevertheless remained in good health to the age of fifteen years, passing her urine from the nipples, and getting rid of f\u00e6eal matters by vomiting. There are cases, moreover, in which it would seem that the mucous lining of the urinary bladder must have had a special power of secreting urine ; the usual discharge having taken place to the end of life, when, as appeared by post-mortem examination, the kidneys were so completely disorganised that they could not have furnished it ; or, having been prevented by original malformation, or by ligature of the urethra, from discharging it into the bladder. A considerable number of these have been collected by Burdach.* In all the older statements of this kind, there is a deficiency of evidence that the fluids were really urinous, urea not having been obtained from them by chemical analysis, and the smell having been chiefly relied upon. The urinous odour, however, when distinct, is probably nearly as good an indication of the presence of the most characteristic constituent of human urine, as is the sight of the urea in its separated form. The passage of a urinous fluid from the skin has been frequently observed in cases in which the renal secretion was scanty ; and the critical sweats, by which attacks of gout sometimes terminate, contain urates and phosphates in such abundance as to form a powdery deposit on the surface. It has lately been ascertained, that in warm climates urea is an element of the perspiration even of healthy persons, j-\nThe metastasis of the biliary secretion is familiar to every practitioner, as being the change on which jaundice is dependent. It is not, however, in every case of yellowish brown discolouration of the tissues, that we are to impute such discolouration to the presence of biliary matter ; and we can only safely do so, when we have at the same time evidence of concurrent disturbance of the biliary apparatus. This disturbance may be of two kinds : either the secreting function of the liver itself may be diminished or suspended, so that the original elements of bile accumulate in the blood; or, the secretion being formed by it as usual, its discharge may be prevented by obstruction of the gall-ducts, so that it is re-absorbed into the blood. The former condition is much the most dangerous of the two ; the re-absorption of the secretion after it has been once eliminated not being\n* Op. cit. pp. 253, 254.\nf L\u00e4nderer in Heller\u2019s Archiv. voL iv. p. 196.","page":462},{"file":"p0463.txt","language":"en","ocr_en":"SECRETION.\t463\nnearly as injurious as the cessation of the eliminating process. In either case, the urinary apparatus is the principal channel through which the biliary matter is eliminated ; the urine becomes tinged with the colouring principle of bile, being sometimes of a yellowish or orange hue, and sometimes of a brown colour with a considerable sediment ; and the presence of the most characteristic constituents of the bile has been determined in the urine. The same result presents itself when the biliary duct has been artificially obstructed by ligature. Other secretions have been found tinged with the colouring matter of bile : thus the pancreatic fluid has been seen of a yellow colour in jaundice ; and the milk has presented not merely the hue, but the characteristic bitterness, of the biliary secretion. The cutaneous transpiration is not un-frequently so much impregnated with biliary matter, as to communicate the tinge to the linen covering the skin ; and even the sputa of patients affected with bilious fevers have been observed to be similarly coloured, and have been found to contain biliary matter. The secretions of serous membranes, also, have been frequently seen to present the characteristic hue of bile ; and biliary matter has been detected, by analysis, in the fluid of the pleural and peritoneal cavities.\nBiliary matter, however, when unduly present in the circulating current, is not removed from it by the secreting organs alone ; for it seems to be withdrawn also in the ordinary operations of nutrition, entering into combination with the solid tissues. Thus, in persons affected with jaundice, we find the skin, the mucous and serous membranes, the lymphatic glands, the brain, the fibrous tissues, the cartilages, the bones and teeth, and even the hair, penetrated with the colouring matter of the bile, which they must have withdrawn from the blood, and which seems to have a particular affinity for the gelatinous tissues.\nMany instances are on record, in which the secretion of milk has apparently been transferred from the mammary glands to some other surface. It might be expected, from what has been already stated regarding kies-tine, that the kidneys should eliminate the constituents of the secretion when the mammary glands are unable to do so. Several cases in which this happened are referred to by Voigtei.* One of these, strange to say, was a male, who was suffering under tumefaction of the mammary glands, accompanying an attack of catarrh. It is well known that the secretion of milk may be formed by the mammary gland of the male under particular circumstances ; but it could scarcely have been anticipated that it would be produced and eliminated through any other channel. A case has been recorded by Koller, however, in which this was unequivocally the case. A young man, suffering under various ailments,\n^Handbuch der Pathologischen Anatomie, tom. i.\nwas affected with a vesicular eruption on the skin of the scrotum, which was considerably distended, and on the thighs ; and these vesicles discharged a large quantity of a whitish fluid, of somewhat spermatic odour, in which L\u00f6wig detected butter, caseous matter, sugar of milk, and alkaline and earthy salts. A fluid, having the appearance of milk, has also been transuded from the skin of the umbilicus, of the axillae, of the groins, and of the back ; from the gastro-intestinal mucous membrane; from the mucous membrane of the genitals ; and from the surface of an ulcer. The following seems an unequivocal case of the vicarious secretion of milk by a very unusual channel.\n\u201c A lady of delicate constitution (with a predisposition to pneumonia) was prevented from suckling her first child, as she desired, by the following circumstance. Soon after her delivery she had a severe fever, during which her breasts became very large and hard ; the nipples were swollen and firm ; and there was evidently an abundant secretion of milk ; but neither the sucking of the infant, nor any artificial means, could draw a single drop of fluid from the swollen glands. It was clear that the milk-tubes were closed ; and as the breasts continued to grow larger and more painful, purgatives and other means were employed to check the secretion of milk. After three days the fever somewhat diminished, and was replaced by a constant cough, which was at first dry, but soon after was followed by the expectoration of simple mucus. After this the cough diminished in severit}7, and the expectoration became easy ; but the sputa were no longer mucous, but were composed of a liquid which had all the physical characters of genuine milk. This continued for fifteen days, the quantity of milk expectorated amounting to three ounces or more in the twenty-four hours. The breasts gradually diminished in size ; and by the time that the expectoration ceased, they had regained their natural dimensions. The same complete obstacle to the flow of milk from the nipples recurred after the births of four children successively, with the same sequel. After the sixth, she had the same symptoms of fever, but this time they were not followed by bronchitis, or the expectoration of milk ; she had in their stead copious sweatings, which, with other severe symptoms, reduced her to a cachectic state, and terminated fatally in a fortnight.\u201d*\nAlthough the menstrual flux cannot be regarded in the light of an ordinary secretion, since it consists in great part of actual blood, yet there are indications that it is the means of removing from the body something that is more injurious to it than a mere superfluity of the circulating fluid. A sudden suppression of the catamenia is frequently followed by symptoms of constitutional disturbance, which neither general nor local abstraction of blood suffices to relieve, and which are only abated\nBulletino delie Scienze Mediche, Apr. 1839.","page":463},{"file":"p0464.txt","language":"en","ocr_en":"464\nSECRETION.\nby tne restoration of the uterine flux, or by the establishment of a similar discharge from some other organ. Hence cases of vicarious menstruation may really be placed on the same footing with those of metastasis of secretion ; and they serve to illustrate and establish the same general truth. Such cases are by no means uncommon, the menstrual flux being replaced by haemorrhages from various parts of the skin, from the mucous membranes, or from glandular surfaces, especially the mammae. The following case, quoted by M. Brierre de Boismont* from the \u201c M\u00e9d\u00e9cine Pratique \u201d of Pinel, is of peculiar interest from the variety of phenomena which it presents.\n\u201c Madlle A. had been subject, from the age of eleven, to attacks of hysteria, which were followed by vomiting of blood. She menstruated at fourteen ; her health was re-established, and the catamenia continued to flow regularly for several months. A sudden fright suppressed the menses, and again hysteria came on. Vicarious menstruation now occurred. The legs swelled and were covered with vesicles, and during six months blood was regularly discharged from them. The left arm swelled, and the legs recovered ; and for a year there was a regular sanguineous discharge from the arm. A third deviation occurred from the left thumb, which had been slightly wounded ; the catamenia flowed from this opening for six months. In the fourth year two wounds were formed on the face from an attack of erysipelas ; one, on the side of the nose, the other on the upper eyelid. For two years the periodic discharge took place from these openings, and it no longer occurred from the thumb. The abdomen in its turn was attacked with erysipelas, and for five months regularly there was a discharge from the navel at each menstrual period. For four months the discharge proceeded from the inner ankle of the left foot ; for two months from the left ear ; for three from the left nipple. When the discharge did not flow from any one part, bleedings at the nose and vomitings of blood took place, preceded by convulsions, pains in the head, and giddiness. After remaining some time at the Salp\u00e9tri\u00e8re, the health of this young female improved, and regular menstruation was established.\u201d\nIt is probable that although the statement of Haller, already quoted, is universally true as a possibility, yet that it is practically verified only in the case of the excretions, the materials of which differ considerably from the nutritious elements of the blood, and accumulate in it when their usual exit-pipe is no longer open, forcing their way (so to speak) through other channels. If it be true, as we have suggested, that the materials of the recremen-titious secretions, as they have been termed, are nothing else than the materials of the blood itself, slightly modified for their special purpose in the very act of elimination, we see\n* De la Menstruation consid\u00e9r\u00e9e dans ses Rapports Physiologiques et Pathologiques.\nwhy, when they are suspended, there is no accumulation of their materials in the circulating s)\u2019stem, and no attempt at the separation of them by other organs.\nInfluence of the nervous system on the secreting process. \u2014 That the eliminating action of the various secreting organs, and the amount and nature of their products, are greatly influenced by the conditions of the nervous system, cannot be doubted by any one who takes a general survey of the facts of this department of physiology. For although we can no more increase, diminish, or otherwise alter any one of our secretions by a mere effort of the will, than we can, \u201c by taking anxious thought, add one cubit unto our stature,\u201d yet there is ample evidence that the state of the feelings has a powerful influence upon many of them, increasing or diminishing their amount, or altering their character*\nA brief review of the phenomena which manifest this influence, will serve as the most appropriate foundation for an inquiry into its nature and extent.\nThe mammary secretion affords, perhaps, more remarkable evidence than any other, of the influence exercised over it by states of mind, in increasing or diminishing it, or in producing a complete change in its properties. Of the increase in the development of the gland at puberty, and still more during lactation, no definite explanation can be given ; to say that it takes place by \u201c sympathy \u201d with the genital organs, being obviously a mere verbal evasion of the difficulty. But the activity of its function, when once it has been fully established, is mainly dependent upon the sensations and emotions connected with the act of suction, and with the thought of the offspring. Although the formation of, milk may be constantly going on, yet it is greatly increased by the application of the infant to the breast. The quantity which can be squeezed from either breast at any one time, and the secretion of which may have occupied several hours, is about two ounces ; and yet during a quarter of an hour\u2019s suction, an infant may draw three or four times that amount.\n* True it is that there are cases in which secretions would seem to be voluntarily produced, as when real tears are shed by performers on the stage, in the personation of their assumed parts. But in such instances, a strict investigation of the mental state leads to the conclusion, that the emotions proper to the assumed character are for a time really felt ; the effort of the will being rather exerted in the change of individuality ( so to speak ) than in the production of the several movements of gesture or expression which are significant of the mental state. And it is always observable that where the actor, possessing the requisite qualifications, can thus transform himself into the character he is personating, so that his tones, looks, and gestures shall be the spontaneous and natural expression of his temporary feelings, he produces a much greater influence upon the spectators, than he can do by the most careful voluntary realisation of his intellectual idea of the mode in which the character should be manifested. In these cases, then, as in all others, it is through the emotions, not directly by the will that the secretion is really excited.","page":464},{"file":"p0465.txt","language":"en","ocr_en":"SECRETION.\t4\u00d45\nWhen the child is applied to the breast, a sudden turgescence is experienced in the organ, known to nurses as \u201cthe draught:\u201d this is probably due to an increased afflux of blood, produced by the mental state, as in ordinary blushing. The \u201c draught \u201d will often take place, and the secretion begin to flow spontaneously from the ducts, at the mere sight of the infant, or at the thought of him when absent, especially if this be associated with the idea of nursing. Analogous phenomena are observed in domesticated Mammalia. Thus a good milch-cow will yield far more at a single milking, than the udder could have contained, so that the secretion must have been rapidly formed during the process. There are certain breeds of cows which will only yield milk when their calves are in sight; and in some instances if a calf should die, its skin is placed over a living calf, the presence of which has the same effect. The most curious instances, however, of the power of irritation of the nipple and of mental emotions to excite the secretion, are those in which its production has long ceased, or has never taken place. Numerous cases are on record in which young women who have not borne children, and even old women past the period of child-bearing, have had such a copious flow of milk, as to be able to act as nurses. In all these instances, the flow appears to have been brought on, in the first instance, by the continued suction of the child, which had been applied to the breast to pacify it ; or by the influence of strong mental emotions, or by both causes combined. It has been lately mentioned by Dr. Me. William*, that the inhabitants of Bona Vista (one of the Cape de Verd islands) are accustomed to provide a wet nurse in cases of emergency, in the person of any woman who has once borne a child, and is still within the age of child-bearing, by continued fomentation of the mammae with a decoction of the leaves of thejatropha carcas, and by suction of the nipple. Still more remarkable proofs of the same influence are furnished by the cases, of which several have now been narrated by credible witnesses, in which males have acted as efficient nurses, f The following, related by Dr. DunglisonJ, is one of the most recent and at the same time most satisfactory upon record ; \u201c Professor Hall, of the University of Maryland, exhibited to his obstetrical class, in the year 1837, a coloured man, fifty-five years of age, who had large, soft, well-formed mamm\u00e6, rather more conical than those of the female, and projecting fully seven inches from the chest ; with perfect and large nipples. The glandular structure seemed to the touch to be exactly like that of the female. This man had officiated as wet nurse, for several years,\n* Report of the Niger Expedition.\nf See the case described by the Bishop of Cork in Phil. Trans, vol. xli. p. 813. ; one mentioned by Capt. Franklin (Narrative of a Journey to the Polar Sea, p. 157.) ; and one witnessed by Humboldt (Personal Narrative, vol. iii. p. 58.).\nJ Physiology, vol. ii. p. 417.\nVOL. IV.\nin the family of his mistress ; and he represented that the secretion of milk was induced by applying the children intrusted to his care to the breasts during the night. When the milk was no longer required, great difficulty was experienced in arresting the secretion. His genital organs were fully developed.\u201d Corresponding facts are also recorded of the male of several of the lower animals.\nThe secretion of milk may be entirely checked by mental emotions, especially those having reference to the offspring. Thus a mother sees her infant in sudden danger, either from illness or accident ; the secretion is entirely suspended, and does not return until the child, having been restored to her safe and sound, is applied to the breast. The death of the infant will frequently occasion the sudden and complete cessation of the secretion. The same result will sometimes happen from powerful emotions unconnected with the infant : thus Sir A. Cooper mentions two instances in which the secretion, though previously abundant, was suddenly arrested by terror. It has been observed by medical men who practise much among the poor, that the apprehension of the brutal conduct of a drunken husband will put a stop for the time to the secretion of milk ; the breast feels hard and knotted, and flaccid from the absence of the fluid ; and some time elapses before the proper amount returns. It may be stated, generally, that whilst a tranquil, cheerful state of mind has a tendency to increase the secretion, the depressing emotions diminish it.\nThe mere increase or diminution of the secretion, from an influence communicated through the nerves, may possibly be accounted for by the influence they seem to exercise over the calibre of the smaller arteries, as shown in the act of blushing, to which \u201c the draught \u201d seems to have considerable resemblance. But no such explanation accounts for the important fact, that not only the quantity but the quality of the milk is changed by mental emotions. Grief, anxiety, fits of anger, or a continual fretfulness, tend to render the milk thin and serous, and to impart to it qualities that excite intestinal irritation, griping, and fever in the child that ingests it. It might be difficult to detect any noxious elements in it by chemical analysis ; but the effect of the fluid upon the delicate system of the infant is a sure indication of their existence. With this knowledge, derived from almost daily observation, we can have no reasonable ground for refusing to credit accounts of still more remarkable results proceeding from the influence of mental emotion on the mammary secretion, such as the following :\u2014\u201c A carpenter fell into a quarrel with a soldier billeted in his house, and was set upon by the latter with his drawn sword. The wife of the carpenter at first trembled from fear and terror, and then suddenly threw herself furiously between the combatants, wrested the sword from the soldier\u2019s hand, broke it in pieces, and threw it away. During the tumult, some neighbours came in\nH H","page":465},{"file":"p0466.txt","language":"en","ocr_en":"466\tSECRETION\nand separated the men. While in this state of strong excitement, the mother took up her child from the cradle, where it lay playing and in the most perfect health, never having had a moment\u2019s illness ; she gave it the breast and in so doing sealed its fate. In a few minutes the infant left off sucking, became restless, panted, and sank dead upon its mother\u2019s bosom. The physician who was instantly called in, found the child lying in the cradle as if asleep, and with its features undisturbed ; but all his resources were fruit'ess. It was irrecoverably gone.\u201d * Such a case might be regarded as a mere coincidence if it stood alone ; but several others of similar character are upon record. Mr. Wardrop mentions -[\u2022 that having removed a small tumour from behind the ear of a mother, all went well until she fell into a violent passion, and the child being suckled soon afterwards, died in convulsions. He was sent for hastily to see another child in convulsions, after taking the breast of a nurse who had just been severely reprimanded ; and he was informed by Sir Richard Croft that he had seen many similar instances. Burdach cites two cases of a similar kind ; in one of which the infant put to the breast of its mother, just as she had received some very alarming intelligence, died in her arms before the eyes of the messenger; whilst in the other, the child having been nursed when the mind of the mother was in violent agitation, suddenly became extremely pale, and after some hours was attacked with paralysis on the right side, and convulsions on the left. Another of a very similar character has been more recently put on record. \u201c A woman while suckling her child became violently excited by the loss of some article which had been stolen from her. She gave her child the breast while in a state of violent passion. The child at first rejected it, but subsequently took a quantity of milk. Soon afterwards violent vomiting supervened. In the course of some hours, the child took the other breast, when it was attacked with violent convulsions, and died in spite of medical aid.\u201d J\nIt will not be requisite to enter into similar details in regard to other secretions, the influence of emotional states on which is a familiar fact. Thus the flow of saliva is stimulated by the sight, the smell, the taste, or even by the idea, of food ; whilst it may be entirely arrested by strong emotion, as is shown bv the well known test often resorted to in India for the discovery of a thief among the servants of a family. All the parties being compelled to hold a certain quantity of rice in the mouth during a few minutes, the offender is generally distinguished by the comparative dryness of his mouthful at the end of the experiment. The gastric secretion is greatly influenced by the emotional states\n* Dr. A. Combe\u2019s Treatise on the Management of Infancy, p. 222., quoted from Dr. Yon Ammon, \u201c Die ersten Mutterpflichten und die erste Kinderspflege.\u201d\nt Lancet, No. 516.\nj Casper\u2019s Wochenschrift, 1845, S. 204.\nbeing usually increased by moderate exhilaration, and diminished by depression of the feelings. Any very strong emotion, however, usually suspends it for a time. The lachrymal secretion, which is continually being formed to a small extent for the purpose of bathing the surface of the eye, is poured out in great abundance under the moderate excitement of the emotions, either of joy, tenderness, or grief. It is checked, however, by violent emotions : hence in intense grief the tears do not flow. It is a well known proof of moderated sorrow when the flow returns : tears, however, do not bring relief, as commonly supposed, but they indicate that the violence of the emotion has passed off. The odoriferous secretion from the skin, which is much more powerful in some individuals than in others, is increased under the influence of certain mental emotions, such as fear or bashfulness, and commonly also by sexual desire.* That the formation of this secretion is due to changes occurring in the blood itself, and that the function of the cutaneous glandul\u00e6 is rather to eliminate than to produce it, would appear from the fact that the characteristic smell of different animals may be detected in their blood when it is treated with sulphuric acid. The influence of fear or of sexual desire on the odoriferous secretions of many of the lower animals is well known ; the emission of a powerful and disgusting smell being not un-frequently a chief means of defence. The odoriferous matter is sometimes poured into the internal cavities, and discharged with the normal excretions, imparting to them its peculiar scent: thus the urine of a cat, voided under the influence of alarm, possesses a strong and disagreeable smell, which is with difficulty got rid of. The halitus from the lungs is in some persons so affected by mental emotions, that a piece of bad news shall almost instantaneously produce foetid breath. A copious secretion of foetid gas not un-frequently takes place in the intestinal canal, under the influence of any disturbing emotion ; or the usual liquid secretions from its walls are similarly disordered. The tendency to def\u00e6cation, which is commonly excited under such circumstances, is not simply due therefore to relaxation of the sphincter ani, as commonly supposed, but is partly dependent on the unusually stimulating character of the f\u00e6ces themselves. It is a prevalent, and, perhaps, not an ill-founded, opinion, that melancholy and jealousy have a tendency to increase the quantity, and to vitiate the quality, of the biliary fluid ; and amongst the causes of jaundice are usually set down the indulgence of the depressing emotions, or an access\n* A series of glandul\u00e6 in the axillary region, bearing a general resemblance to the sudoriferous glands, but of larger size, have been supposed by Prof. Horner (Amer. Journ. of Med. Sei. Jan. 1846), and by M. Kobin (Gaz. Med. Sept. 13. 1845), to be specially concerned in the elimination of the peculiar odoriferous secretion of this region. These glandul\u00e6 have been shown by Prof. Homer to be unusually large in the negro, whose axillary odour is peculiarly strong.","page":466},{"file":"p0467.txt","language":"en","ocr_en":"SECRETION.\t467\nof sudden and violent passion. There can be no doubt, however, that a disordered state of the biliary secretion is frequently rather the cause than the consequence of a melancholic state of mind ; the blood being sufficiently vitiated by a deficient elimination of bile, to have its due relations with the nervous system seriously disturbed, before any obvious indications of that deficiency make their appearance in the jaundiced aspect of the cutaneous surface.\nThese and similar phenomena afford clear proof of the influence exerted over the secreting processes by mental states ; and it is scarcely to be imagined that this influence can be exerted through any other channel than the nervous system. If we further inquire to which division of the nervous system we are to attribute the conveyance of this influence, we shall find reason to regard it as chiefly, if not entirely, operating through the portion commonly known as the sympathetic. For there are many secreting organs which are supplied with no other nerves than those which they receive from this division, so that they cannot possess any connection with the cerebro-spinal centres except through its medium. The mammary glands, which are supplied by the spinal nerves as well as by the sympathetic, may be considered as requiring such a direct communication with the cerebro-spinal centres, inasmuch as their secretion is made, for obvious purposes, greatly dependent upon sensations directly affecting themselves, which is rarely the case elsewhere. The lachrymal and salivary glands would seem to have a more direct and exclusive connection than most others, with the cerebrospinal centres ; but perhaps this may be more apparent than real, for the fifth pair, from which they are supplied, seems in many respects to combine the attributes of a sympathetic with that of a proper cranial nerve; and bearing in mind the minuteness and the universality of the distribution of the sympathetic plexuses upon the trunks of the bloodvessels, we see that even these glands, like others, may be subjected to its influence.\nIf we further examine into the mode in which that influence is exerted, we shall, perhaps, find reason to attribute it to the effect of nervous agency, rather upon the walls of the blood-vessels and upon their contents, than upon the secreting structures themselves. For, as already remarked, the variations in the quantity of a secretion may be accounted for by such an increase or diminution in the access of blood as we know to take place, through an alteration in the calibre of the vessels, in the act of blushing or the paleness of fright ; and the feelings experienced by the nursing female harmonise well with this supposition. On the other hand, the perversion of the quality of a secretion, which may take place as a result of mental emotion, would seem rather due to an alteration in the constituents of the blood previously to the elimination of the secretion, than to the exercise of any influence upon the secreting structure\nitself. For we find, in the case of the peculiar odorous matter for example, that it may be eliminated in a vaporous form by the air-passages, or by the intestinal canal ; or that its taint may be imparted to the liquid secretions of the intestinal glandul\u00e6 ; or, again, that it may be communicated to the urinary excretion : and this variety in the channels of escape of the same kind of material, pretty clearly indicates that it must have pre-existed in the blood. There are many other facts which confirm this view, by indicating that the condition of the blood whilst circulating in the vessels may be influenced by mental emotions, which probably act upon it through the medium of the sympathetic nerve; but of these it is scarcely the place to speak.\nAnother class of evidence, as to the exertion of an influence by the nervous system upon the secretory function, is furnished by observation of the results of the interruption of that influence, either by a diseased condition of the nervous centres or nerve trunks, or by experimental interference. One of the most familiar of these, on account of its frequent occurrence, is the change in the character of the urine in cases of paraplegia ; resulting, as it would seem, from the secretion of an undue quantity of alkaline mucus from the lining of the bladder* Various experiments have been made upon the nerves of the kidney, which seem to indicate that the normal secretion of urine is dependent upon their integrity. Thus Krimerf states, th^t division of any of the nerves of the kidney occasioned albumen and the red colouring matter of the blood to pass into the urine, their proportion increasing as that of the regular constituents of the urine diminished. Division of the vagus did not put a stop to the secretion of urine; but rhubarb and prussiate of potass taken by the mouth ceased to pass off by the urine, which at the same time acquired greater specific gravity from containing serum of the blood. After division of the spinal cord in the dorsal or lumbar region, the urine became limpid like water; and division of the sympathetic neive in the neck caused it to become alkaline and albuminous. Br\u00e4chet and Miiller have both experimented on the effects of the division of the sympathetic nerves which are distributed upon the renal artery. The former divided the trunk, and connected the divided ends by a canula, so as to allow of the continued passage of blood, whilst the nervous influence was completely intercepted ; the latter produced the same condition by applying a ligature around the renal vessels, so tightly as to destroy the texture of the renal nerves at that point, and then relaxing it again, so as to permit the re-establishment of the circulation. In both cases the effect was similar ; the secretion of true urine being interrupted, but a sanguineous fluid passing into the\n* The nature of this change has been elsewhere considered. See Vol. III. p. 721 T. art. Nervous\nQuoted in Muller\u2019s Physiology (Baly\u2019s Translation), p. 470.","page":467},{"file":"p0468.txt","language":"en","ocr_en":"468\tSECRETION.\nureter. Miiller states that a remarkable softening of the kidney was always one of the results of these experiments.\nNumerous experiments have been made to determine the degree of dependence of the secretion of the gastric fluid upon the nervi vagi ; to these experiments copious references have elsewhere been given*, and we shall therefore only here allude to their results. The temporary suspension of the digestive process appears to be an invariable result of the complete division of the par vagum on both sides ; and many of those who have witnessed this result have somewhat hastily concluded, that the secretion of gastric fluid is dependent upon nervous agency conveyed through that nerve. But it has been observed, in several instances, that the digestive powers have returned after a time, animals which were becoming much emaciated having recovered their flesh ; and it is obvious, therefore, that the secretion of the gastric fluid can not be dependent upon the supply of nervous agency through the par vagum, as some have supposed it to be. It is true, that in a large proportion of the experiments made to determine this question, there has been no appearance of any return of the digestive power, after complete section of the par vagum on both sides ; but there are various modes of accounting for this fact. The animals on which this experiment has been made, usually live for only a short time afterwards, on account of the disorder of the respiratory processes, which is one of the results of the operation ; so that all which is proved by the great bulk of the experiments is, that the digestive process is generally arrested during the short time that the animal lives after the vagi have been divided or tied. And such negative results, as Dr. J. Reid has very justly observed, \u201c can never overthrow the results derived from positive experiments, provided that these have been accurately performed, and are free from all sources of fallacy.\u201d f\nWith these facts before us, it is much to be desired that the experiments just cited, as to the influence of section of the renal nerves upon the secretion of the kidney, had been sufficiently prolonged to ascertain whether the effects described are transient, and whether the real secretion would be restored if time were permitted. And it is obvious that, as they at present stand, no such experiments can serve as an adequate foundation for the hypothesis entertained by some, that the act of secretion is dependent upon nervous influence, or, in other words, that nervous agency supplies a condition without which it cannot take place.\nThere is another group of phenomena bearing upon this question, though less closely related to it, \u2014 namely the changes in the state of nutrition in parts whose nerves have been injured, and which are thereby rendered insensible. The close affinity, however, already shown to exist between the functions\n* Yol. III. p. 900. art. Par Vagum. f Ibid.\nof Nutrition and Secretion, is sufficient to make it apparent that they must stand upon the same footing in this respect, and that whatever is true as to the relation of either of them to the nervous system, must be true also of the other. Now it is an observation very frequently made, that parts whose nerves have been paralysed are peculiarly disposed to suffer from destructive inflammation, or to undergo a gradual wasting. The latter of these changes is easily accounted for on the general principle dwelt on under the head of Nutrition, that the degree of nourishment which any organ or tissue receives, depends upon its functional activity; and thus not merely the muscles, but all the textures of a paralysed limb gradually waste away, the disuse of its muscles occasioning a stagnation in the circulation through the entire part. Of the former result it is necessary to make a careful examination, that we may be prepared to estimate it at its true value. One of the cases most frequently quoted in this connection, is the effect of section of the trigeminus in producing destructive inflammation of the eye-ball, as first shown by Magendie, and confirmed by many subsequent experimenters. A full account of these effects has been already given in another part of this work (see Fifth Pair), and it is therefore unnecessary to repeat them here. A corresponding result may be produced by disease. A case is related by Mr. Stanley*, in which there was impairment of the whole nutrition of one side of the face, with frequent attacks of erysipelatous inflammation, bleeding from the nose, central penetrating ulceration of the cornea, and, at last, destructive inflammation of the tunics of the eye, in consequence (as it would appear) of destruction of the trunk of the trigeminal nerve of that side by the pressure of a tumour near the pons. No such destructive effects ensue on section of any of the other cranial nerves ; the only injurious influence exercised on the eye by any such operation, being the tendency to inflammation from irritants which the paralysed orbicularis palpebrarum does not shut out or help to remove. But, on the other hand, cases are occasionally to be met with (of which the author has himself witnessed more than one) of the complete paralysis of the ophthalmic division of the fifth pair, which has existed for sometime without any other result than a degree of dryness of the surface of the eye from deficient secretion, and a disposition to superficial inflammation from irritating particles of whose presence no warning was given by sensation, and for whose removal there was consequently no provision. Such exceptional cases must be admitted as proving that, however unfavourable may be division or injury of the trigeminus to the continued healthy nutrition of the .eye, still this may be maintained; and that it is consequently no more essentially dependent upon \u201cnervous influence,\u201d supplied through that channel, than is the secretion of gastric fluid upon the\n* Medical Gazette, vol. i. p. 531.","page":468},{"file":"p0469.txt","language":"en","ocr_en":"SECRETION.\t469\npower supposed to be transmitted by the par vagum.\nThat the nutritive operations of other parts, however, are usually less vigorously and correctly performed when the nerves have been paralysed, than when they retain their entire integrity, would appear from numerous other facts, of which the following are examples. A case is related by Mr. Swan* * * \u00a7 in which a man\u2019s wrist having been injured by a cord having been very tightly drawn round it, there was partial paralysis of the hand, with constantly repeated ulcerations of its dorsal surface ; and on amputation seven years afterwards, there was found to be induration of the median nerve, with adhesion of the tissues beneath the annular ligament. The following case, stated by Mr. Paget f on the authority of Mr. Hilton, is still more remarkable. \u201c A man was at Guy\u2019s Hospital, who, in consequence of a fracture at the lower end of the radius, repaired by an excessive quantity of new bone, suffered compression of the median nerve. He had ulceration of the thumb, and fore and middle fingers, which had resisted various treatment, and was cured only by so binding the wrist, that the parts on the palmar aspect being relaxed, the pressure on the nerve was removed. So long as this was done, the ulcers became and remained well ; but as soon as the man was allowed to use his hand, the pressure on the nerves was renewed, and the ulceration of the parts supplied by it returned.\u201d\nThat the reparative processes are affected, as well as those of ordinary nutrition, by the loss of nervous power, is a matter of familiar observation. A striking example to this effect is mentioned by Mr. Travers.J A man was rendered paraplegic by fracture of the lumbar vertebrae, the same accident having also fractured his humerus and his tibia. The former, in due time, united ; the latter did not.\nThis peculiar affection of the nutritive processes appears rather dependent upon lesion of the sensory than of the motor nerves. Thus we have seen that the disorganisation of the eye after section of the fifth pair, takes place when only the sensory nerve of the part is affected, and that no such result occurs when only the motor nerves of the orbit are divided. In cases of disease or injuries of the spine, it has been noticed that sloughing of the bladder or other parts has occurred earlier and more extensively when sensation, than when motion alone, has been lost. And Mr. Curling has noticed \u00a7 that two men having been taken at nearly the same time to the London Hospital with injury of the spine, one of whom had lost only the power of motion in the lower extremities, whilst the other had lost both motion and sensation, at the end of four months the atrophy of the lower extremities had advanced much further in the latter case than in the former. These phenomena\n* On Diseases and Injuries of the Nerves, p. 60.\nf Loc. cit.\nJ Further Inquiry concerning Constitutional Irritation, p. 436.\n\u00a7 Med. Chirurg. Trans, vol. xx. p. 342.\nwould seem to harmonise with the view, that it is especially through the sympathetic system of fibres that the peculiar influence is exerted, whose continual agency we only recognise by the results of its withdrawal. For if, as already remarked, the fifth pair may be considered as the sympathetic of the head, the Gasserian ganglion may probably be regarded as belonging to the sympathetic system ; and it has been observed by Magendie, and confirmed by Longet, that the destructive inflammation of the eye ensues more quickly after division of the trigeminal nerve in front of the Gasserian ganglion, than when the division is made between that ganglion and the brain. If this be true of the Gasserian ganglion, it is probably true, also, of the ganglia on the posterior roots of the spinal nerves ; and thus the disordered nutrition which results from injury to the trunks of these nerves, and which is not to be accounted for by the mere disuse of parts, may be attributed, with some show of probability, to the interruption of the connection with the sympathetic system, which is specially established by these ganglia and their communicating cords. But it is to be remembered, on the other hand, that defective or disordered nutrition is a marked result of injuries of the spinal cord, whilst the sympathetic centres remain uninjured ; and that general atrophy is a frequent consequence of chronic diseases of the brain. Fresh evidence is much required, therefore, to determine the relative shares of the cerebro-spinal and sympathetic centres, in regard to the influence exerted by them over the organic functions.\nBy the survey we have now taken, we are in some degree prepared to estimate the degree and nature of the influence exerted by the nervous system on the nutritive and secretory functions, and to inquire into the validity of the several doctrines which have been propounded on the subject : \u2014\n1. The first of these theories may be stated in the words of Dr. Wilson Philip, one of its most distinguished advocates :\u2014\u201c It appears,\u201d he says, \u201c that the nervous influence is necessary to the function of secretion. It either bestows on the vessels the power of decomposing and recombining the elementary parts of the blood, or effects those changes by its direct operation on this fluid. From many facts stated or referred to in my inquiry, it appears that the vessels possess no powers but the muscular and elastic ; and that the former, as well as the latter, is independent of the nervous system. Nor is it possible to conceive any modification of these powers by which they could become chemical agents, and thus be enabled to separate and recombine the elementary parts of the blood. The first of the above positions may, therefore, be regarded as set aside, and the necessary inference seems to be, that in the functions of secretion the vessels only convey the fluids to be operated on by the nervous influence.\u201d It will, perhaps, be sufficient to say of this hypothesis, that having been put forth at a\nH H 3","page":469},{"file":"p0470.txt","language":"en","ocr_en":"470\tSECRETION.\ntime when the real nature of the secreting structure was altogether unknown, and when the choice seemed to lie only between the influence of the nerves and that of the vessels, it is totally fallacious now that a third agent has been discovered, to which all analogy would lead us to refer, at any rate, the chief instrumentality in the operation. The principal experiment adduced in support of this hypothesis, and of the identification attempted by Dr. Philip between nervous agency and galvanism, was the effect of section of the par vagum in checking the secretion of gastric fluid, and the renewal of the process under the influence of galvanism. We have already shown the utter invalidity of this result as a ground for any such inference; and it only remains to show the inconsistency and insufficiency of the hypothesis itself, which is easily done. For, as Dr. Prichard has justly remarked *, \u201c if we begin by supposing the existence of the cause assigned, we shall find that there is one agent, namely the galvanic fluid, operating on one material, which is the blood, and effecting its decomposition. How, then, we may ask, does it happen that so many different substances are, in different examples of the same process, the results of this single operation ? In other chemical decompositions, as when water is decompounded by the galvanic fluid, the result is the same and uniform. But in the instance supposed, the operation of the same chemical agents upon each other is followed by the formation of products of the most different descriptions : in one part of the vascular system the blood is converted into bile ; in another, by the operation of the same chemical agent, into milk ; in another, into tears.\u201d This variety of effects can only be explained by attributing them to the special endowments of the several secreting organs through which the nervous power is supposed to act ; and if it be thus necessary to admit that such special endowments do exist, by which the particular nature of the secretion is determined, the question naturally arises, Of what use is the nervous power at all ?\n2. The second hypothesis, framed to meet this objection, supposes, to use the language of Prof. M\u00fcller, that \u201c the influence of the nerves on the glands merely enables the secreting substance, in each gland, endowed with peculiar properties, to exert its chemical action.\u201d In order to sustain this hypothesis, it is necessary to show that the processes of secretion and nutrition are not only modified by the division of the nerves by which their organs are supplied, but that they are altogether suspended by that operation ; the secreting or growing structures having no functional power of their own, sav\u00e8 when connected with certain nervous centres, which are supposed to transmit to them the requisite vital force : much as in a factory there may be seen a great variety of machines, each of\n* Review of the Doctrine of a Vital Principle, p. 198.\nthem constructed to perform a certain special action, but all of them dependent for their power of carrying it into effect upon a general motive power transmitted to each. We shall, perhaps, more conveniently and satisfactorily examine into the merits of this hypothesis, by bringing it into comparison with the next.\n3. The third doctrine, of wThich Dr. Alison has been one of the most philosophical and consistent advocates, is to the effect that the whole organic or vegetative life of animals,\u2014 i. e. every thing which goes on in them without the intervention of any sensation or other mental act, including the functions of nutrition and secretion, \u2014 may go on without the intervention of the nervous system, and stands in no relation of dependence to any changes in nervous matter ; but that these changes exert a powerful controlling and modifying influence on the organic functions, increasing or diminishing their activity, or even altering their character ; just as, to use the appropriate illustration of Dr. John Reid, the movements of a horse are influenced by the hand and heel of the rider, although they are in themselves independent of him, being executed in virtue of the power inherent in the animal.\nNow, in support of this last view of the subject, it may be urged, in the first place, that in one great division of the organised world, namely, in the vegetable kingdom, the functions of nutrition and secretion are performed, not only independently of, but without any kind of influence from, a nervous system ; each act being the result of the properties inherent in the several parts of the structure itself, called into play by the appropriate stimuli. We should have a right to expect, therefore, that the corresponding functions in animals should be adequately performed by a similar mechanism ; and it is fair, therefore, to throw the burthen of proof upon those who maintain the contrary. If we follow out in this case the great general principle of Cuvier, which every day\u2019s experience only shows to be more strictly correct and more widely applicable, \u2014 that the different classes of animals may be considered as so many experiments ready prepared for us by nature, who adds to \u2019or takes from their several organs, just as we might wish to do in our laboratories, showing us at the same time the various results of these combinations,\u2014we see that a comparison of different organisms affords us a much better ground for the determination of this question, than can be obtained from the results of such experiments as have been already cited ; it not being possible to make such experiments, without such injury to the organism as is of itself a serious disturbing cause. We notice, on looking at the highest animal, that the organic functions are brought into very close relation with the animal powers, and are liable to be considerably modified by the exercise of the latter. But, as we descend the scale, we find the nervous system constituting a less and less predominant part of the organism, and the apparatus of organic life becoming more and","page":470},{"file":"p0471.txt","language":"en","ocr_en":"SECRETION.\t471\nmore disconnected from it ; until, in zoophytes, we are scarcely able to distinguish a nervous system at all, whilst all the operations of growth, nutrition, and secretion take place very much as in plants, in which no nervous system exists. Thus we find that \u201c the nervous system lives and grows within an animal, somewhat as a parasitic plant does in a vegetable,\u201d deriving its nutriment from the structure in the midst of which it is developed, and capable of exercising a certain action upon it, but being strictly a superadded part, and having rather an adaptive than an essential connection with that structure.\nNow this view has derived from late discoveries in minute anatomy, as complete a confirmation as any such facts are capable of affording. For it has been shown, not merely that the functions of nutrition and secretion are common to animals and plants, but that the component elements of the organs by which they are performed are in both instances essentially the same. We have seen that the act of secretion is effected, even in the most complex gland, by the agency of aggregations of cells, each of which lives for and by itself, and appears to be dependent upon no other external conditions, than those which are required for the growth of the simplest cellular plant, namely, food and warmth. And it is difficult to conceive how, over that most essential part of the secreting process \u2014 the de-velopement of the secreting cells \u2014 the nervous system can exert any direct influence.\nAnother natural experiment, whose immediate bearing is rather upon the physiology of nutrition than upon that of secretion, but -which is really as conclusive in regard to the latter as the former, is exhibited to us in the early growth and developement of the embryonic structure ; which makes considerable progress, especially in invertebrated animals, before any trace of the nervous system can be detected. And in the human species the case is not unfrequent, of the f\u0153tus coming to its full size with the usual variety of textures in its composition, but without either brain or spinal cord. It has been said, however, that in such instances the ganglia of the sympathetic system probably exist, and supply the influence supposed to be needed; but there are cases on record, in which these would seem to have been carefully looked for and not detected.* And moreover, even if their uniform presence were to be admitted, and the power of sustaining the operations of nutrition and secretion be supposed to reside in them, how are we to explain the effects of injuries of the brain and spinal cord, the ganglionic centres being left intact ? We can see no other consistent account of these phenomena, than that which is presented by the last of the three hypotheses enumerated ; the functions of nutrition and secretion (like the contractility of muscular fibre) not being regarded as dependent for their ordinary exercise upon any power supplied by the nervous system,\n* Elber, de Acephalis, pp. 31. 35. 45.\nbut being considered to be modified by causes operating through it.\nAnd that this is the true view of the matter, would further appear from a careful examination into the nature of the phenomena which follow the section or injury of nerve-trunks or centres, and which have been supposed to indicate the impossibility of the continuance of true nutritive operations after the withdrawal of the hypothetical nervous influence. In the first place, the effect produced by section of those nerves which are supposed to exert the greatest influence, is probably not in any case a simple suspension of the nutritive operations, nor a death of the part ; but it is of the nature of inflammatory action, involving disordered nutrition and perverted secretion. Further, this disordered condition does not seem to be the direct result of the paralysis of the nerves, so much as an indirect consequence of the want of power to resist morbific causes. \u201c If the section of the sensitive nerves of a part,\u201d it has been observed (with special reference to the inflammations of the eye, the lungs, and stomach, consequent upon section of the fifth pair and par vagum), \u201c were the direct cause of its inflammation, we should expect to see inflammation in all parts of which the sensitive nerves are cut ; whereas the phenomenon in question is seen only in a few parts ; and in those parts it originates, and is chiefly seated, in a single texture, viz. the mucous membrane : that membrane is distinguished from others in the body by its power of bearing the contact of air, of foreign substances, and of excretions elaborated within the body, with impunity. This power seems obviously connected with its vital power of throwing out, when irritated, a mucous secretion, which protects it equally as the cuticle protects the true skin ; and this adaptation of the quantity of protecting mucus to the irritation which may act on a mucous membrane, may be very naturally supposed to depend on its sensibility, and to cease when its sensitive nerves are divided, and allow the mucous membrane to inflame and slough, equally as a serous membrane would do from the irritations which, in the natural state, excite only a healthy action upon it. On this supposition, the inflammations in question depend, not simply and directly on the division of nerves, but on the action of the air, the food, the bile, &c., on mucous membranes deprived of their sensibility, and thereby in great measure of their protecting mucus ; and bear an analogy to the inflammations of the same membranes which frequently take place from deficiency of the mucous secretion, in cases of death by starvation, and towards the close of lingering and exhausting diseases.\u201d * And lastly, even supposing the inflammatory changes to be the direct result of the paralysed state of the nerves, they in themselves afford conclusive evidence against the doctrine, that the nervous influence is essential to the nutritive and\n* Brit, and For. Med. Rev. vol. iii. p. 14.\nH H 4","page":471},{"file":"p0472.txt","language":"en","ocr_en":"SEMEN.\n472\nsecretory operations ; for, as Bichat observed, respecting the inflammation and suppuration of the testicle after its complete isolation from the larger masses of the nervous system, the establishment and maintenance of a morbid secretion was just as conclusive evidence of the independent character of the process, as if the normal product of the testis had been continued.*\nUpon all these grounds we feel justified in asserting, that no adequate ground has yet been furnished by pathological observation and experiment, for the establishment of any other doctrine as to the relation between the nervous system and the organic functions, than the last of those just stated. It is perfectly conformable to the facts supplied by comparative physiology, and by the history of developement ; and may be said to rest upon them as upon a broad foundation. It harmonises sufficiently well with the results of experiment and pathological observation on man and the higher animals, to be considered as giving the most satisfactory interpretation of them which, in the present state of our knowledge, seems likely to be attained ; and if it be not the whole truth, is evidently not far from it. On the other hand, the doctrine that nervous influence is essential to the performance of the nutritive and secretory operations, is opposed to the mass of phenomena presented in the vegetable world, in the lower tribes of the animal creation, and in the history of the developement of the higher ; to the exact knowledge we now possess of the structure of glands themselves ; and even to the results of those experiments and pathological observations which have beer, relied upon to prove it, when these are carefully sifted.\t( W. B. Carpenter.)\nSEMEN. \u2014 Sperma; Sperm, Engl.; Gr. imrepfia ; Germ. Samen; Fr. Sperme. \u2014 Male animals, when perfectly developed and capable of procreation, secrete a thickish white fluid in their testicles, which possesses the faculty of inciting the generative parts of corresponding female individuals to a series of processes, the ultimate result of which is the developement of the embryo. This fluid, so indispensably necessary as the medium of sexual generation, is the seed or semen.\nHistological elements of the semen. \u2014 Microscopic analysis proves that the most essential morphological constituent of the semen consists in the spermatozoa (animalcula sper-matica), a number of corporeal elements, distinguished by their specific shape, and by their peculiar phenomena of vitality. The attention of physiologists and others has been actively directed towards them, ever since their discovery by Ham and Leuwenhoelc ; and the most varied and frequently the wildest assumptions and conjectures have been occasioned in consequence. In spite of the intimate relation which they evidently occupy with regard to the procreative capacity of the semen, they\nhave been considered, even up to the most recent period, as independent animal organizations, or parasitical animals. The reason adduced for such a conjecture is the peculiar motion which may be observed in almost all of these formations, and which in many cases bears a striking resemblance to voluntary motion. This assumption, however, is perfectly irreconcileable with our present knowledge of the quality and developement of these bodies, based as it is principally upon the discoveries of It. Wagner, Von Siebold, and K'\u00f4ll\u00efker.\nWith our present means of a scientific diagnosis, it can be proved that the formations in question are mere elementary constituents of the animal organization, like the ova, constituents equally as necessary for the spermatic fluid as the blood-globules are for the blood. The remarkable phenomena of the life of spermatozoa are quite analogous to those phenomena of motion observable not only in animal formations, but also in vegetable structures; as, for instance, in the spores of the algae and of the lower species of fungi, in the so termed vibriones, which grow out into the fibres of the conferva called \u201c hygrogrocis.\u201d\nThe denomination of \u201c animalcula sperma-tica, spermatozoa,\u201d is based upon the assumption that these moveable elements of the semen are animated organizations endowed with all the attributes of animals ; and they were, accordingly, classified among the Infusoria or Helminthea. K'\u00f4ll\u00efker*, the first who most distinctly expressed the assertion that the so called spermatozoa are mere elementary parts of the organization, mere histological elements, applied to them the name of fila sper-matica; a designation which would certainly be appropriate, if all the formations in question possessed a linear form. V. Sieboldf, rejecting the old name on the same grounds, has proposed that of spermatozo\u00efdes, which, however, we consider as still less happily chosen. We confess that we cannot exactly see the necessity of creating a new designation for these spermatic elements at all, the less so as many names in our scientific nomenclature specify something quite different from that which they immediately indicate. We shall therefore principally use for the future the old name of spermatozoa, admitting at the same time that it is not quite a suitable one, and that it might probably be better expressed b}T the designation of corpuscula seminis, or spermatocoeci, by which they have occasionally been distinguished.\nThe spermatozoa, or corpuscula seminis, are not merely normal, but in fact the essential constituents of the procreative semen. Indeed, it appears, in many cases, especially among the lower animals, that they are its only constituents. The presence of a fluid, liquor seminis, to hold them in sus-\n* Beitr\u00e4ge zur Kenntniss der Geschlechtsverh\u00e4ltnissen und der Samenfl\u00fcssigkeit wirbellosen Thiere. Berlin, 1841.\nt Uber die Spermatozooiden der Locustinen. From the Acta Acad. Leop. Carol. Nat. Cur. vol. xxi. Part I. S. 1.\nAnatomie G\u00e9n\u00e9rale, tom. iv. p. 604.","page":472},{"file":"p0473.txt","language":"en","ocr_en":"SEMEN.\n473\npension, is not perceptible in these cases ; and it would be perfectly unnecessary, when procreation takes place, without sexual connexion, in the water. The presence of such a medium can certainly not be denied among the verte-brata; but it remains to be proved whether it is of specific importance to the semen, or whether it does not perform a subordinate part both in a histological and physiological point of view. It is not quite improbable that the presence of this liquor seminis is merely incidental, and that it stands in a certain connexion with the process of developement *, and perhaps also with the formation of the spermatozoa. In a physiological point of view, it may perhaps serve as the medium of a more easy and safe transmission of the spermatozoa to the ovaries. It may form for the spermatozoa a medium, which serves partly for the better developement of their peculiar motions, and partly to afford them an immediate protection against the external influence of many injurious agencies.\nAt any rate, the liquor seminis appears to be much more an accessory product of secretion in the glandular elements of the testicles than a necessary and essential constituent of the semen. A comparison with the liquor sanguinis would therefore not be applicable. We would rather draw attention to the fact that a peculiar fluid is also secreted in the female generative organs. For instance, among the mammalia the fluid contents in the Graafian follicles, which, taking it in all its bearings, we feel inclined to consider as analogous to the liquor seminis.\nThe liquor seminis, wherever it occurs, exhibits itself as a homogeneous, transparent fluid, existing always only in a small quantity. It is frequently only observed after the addition of a re-agent, as acetic acid and alcohol, when it coagulates and forms a fine, delicate, granular matter betwixt the spermatozoa.\nFormerly, one of the authors of this article, i\u00a3. Wagner, distinguished, in addition to the spermatozoa, other particular globular formations\u2019}*, which he called granula seminis, and which he considered at that time as independent elements. At the present moment, however, it may be looked upon as decided that these formations occupy a relation of developement (genetischen Beziehung) to the spermatozoa J, being, in fact, the vesicular ele-\n* This modifies or changes the view respecting the function of the liquor seminis, which was formerly entertained. See Rudolph Wagner\u2019s Elements of Physiology ; translated by Robert Willis. Part I. p. 74. 3d German edition, S. 53.\nf Fragmente zur Physiologie der Zeugung, p. 29., in the Transactions of the Math. Physical Class of the Roy\u00e2l Bavarian Academy of Science, Munich, 1837. Lehrbuch der Physiol. 3d edition, S. 13. English edition by Willis, p. 5.\n+ Stein likewise is at present of this opinion. (Yergleich. Anat. und Phys, der Insekt. S. 107.) after having previously represented these formations in the shape of a peculiar theory of procreation.\nments which have since been generally acknowledged as the formative cells of the spermatozoa. The former opinion of R. Wagner, at a time when the formative processes of the spermatozoa was so little known, was apparently justified by the circumstance that these bodies are found not merely in the testicles, but likewise in the vasa deferentia. This fact is even at the present moment of great interest. It proves that the developing cells of the testicles are not all of them used for the production of the spermatozoa, but that a number of them are removed in their primitive state, such removal being either accidental, or caused by their incapability of a further developement.\nWe need not enter here into other irregular and fluctuating constituents of the semen. They are principally found only in the duct of the generative organs, and generally consist of fatty globules, of several epithelial cells, &c., which, from their characteristic appearance, are readily perceived to be incidental admixtures.\nPeriodical developement of the spermatozoa and testicles.\u2014The developement of the spermatozoa in the interior of the testicles does not take place constantly and uniformly during the whole of life ; but a genuine semen, with its characteristic histological elements and physical peculiarities, is only secreted at the period of sexual maturity, and then only during the period of rutting. It is likewise only at this period that the semen is capable of acting with fructifying influence upon the female organs of reception. In those cases where the periods of rutting repeatedly occur in one year, where, as in human beings, and among most of the domestic animals, they are hardly separated by any perceptible or distinct intervals, the spermatozoa are certainly found at all times from the period of puberty thoughout life. But even in these cases it may be assumed that the production of the spermatozoa is principally confined to the respective periods of rutting, although not perhaps entirely limited to it.\nThe spermatozoa, like all other elementary constituents of the animal body, are likewise subjected to a process of re-formation (Ruck-bildungs-process), if they do not make their exit from the body. If the periods of rutting are separated from each other by longer in\u00b0 tervals, this process affects likewise the organs for the transmission and for the preparation of the liquor seminis. The testicles and vasa deferentia in these cases decrease considerably in size and developement until the commencement of a new sexual period leads them towards a new state of turgescency, and anew capacitates them for the production of spermatozoa.\nThe period of rutting among most animals, at least in our climate, is associated with the commencement of the warmer season. The testicles then receive a larger influx of blood ; they increase in size ; the walls of the spermatic canals become thicker, their lumina larger. These changes of the generative organs","page":473},{"file":"p0474.txt","language":"en","ocr_en":"474\nSEMEN.\nmay be most readily traced among birds, the increase of size of the testicles being very striking with them at the period of copulation, as proved by the researches of Hunter, as quoted by Owen*, to which we may add our own, which likewise have been instituted with the sparrow.\nDuring the winter the testicles only possess a very small size. In a specimen which we examined in the middle of January, they scarcely measured a millimeter. Both testicles were equally developed, had a globular shape, and weighed together (in a fresh state) about 3 milligrammes. The vasa deferentia, which we were only enabled to discover after a very accurate examination, appeared in the shape of a couple of thin and almost solid strings. Henceforward the testicles and spermatic ducts begin to grow, although at first but very slowly. The increase of the testicles does not however extend itself in all directions. It is limited principally to the longitudinal diameter, thus causing the subsequent kidney form of these parts. Towards the end of the month of January they reach the length of about If Mm., whilst the transverse diameter is not materially changed ; weight of both testicles =4 Mgrs. In the middle of February the length reached about 2 Mm., the width If., the weight 6 Mgrs. By the end of the month the organ enlarges itself to a body of 2f Mm. in length, If- Mm. in width, with a weight of 8 Mgrs. At the commencement of the next month the testicles measured 2f Mm. in length, 2 Mm. in width. They had a weight of 15 Mgrs., which increased at the middle of the same month to 48 Mgrs., the length simultaneously increasing to 3 f Mm., the width to 2-\u00a7. The subsequent developement of the testicles is much more rapid and extensive. At the commencement of April we found them to be of a considerable size, with a longitudinal diameter of 8 Mm., a width of almost 7 Mm. The weight, we are sorry to say, we did not note down. The microscopical analysis now for the first time exhibited to our view spermatozoa in the different stages of developement. The former stages of developement had not been capable of producing such formations.\nThe testicles obtain their perfect developement towards the end of this month (April), when they measure 10 Mm. in length, with a width of 8 Mm., and a weight of nearly \u00a7\u2022 Gramme (0.575 Gramme.).\nThe researches which we have now communicated are of course only of an average value or validity, and cannot be applied to all individual cases. Deviations from them are therefore by no means rare. Individual specimens exhibit either a very premature or a very late developement. Thus we met with, for instance, as early as the middle of January, specimens, the testicles of which had a length of 2 Mm., a width of 1 \u00a3, and a weight of 6 Mgrs., such occurring usually only four weeks afterwards. Towards the end of\n* Yol. I. p. 354. art. Aves.\nthe same month the testicles of another individual measured a length of 2f, a width of 2 Mm. As an opposite instanoe, we may mention that we found at the end of the month of February, in the testicles of a sparrow, a length of 1* Mm., a width of 1 Mm.\nForm and history oj developement of the spermatozoa. \u2014 The first thing that strikes the observer, on entering into a microscopical research of the semen of a great number of animals, is the difference of the shape of the spermatozoa. The specific shape of these elements generally corresponds with the individual classes, genera, and species, and this so distinctly, that one may often safely venture to infer from it the systematic position and the name of the animals investigated. We will not, however, venture to determine whether this variety of the shape is connected with the rich variety of animal formations, or whether the specific shape of the spermatozoa has a determining influence upon the developement of the germ into a certain specific form. Such a conjecture, however, would certainly not be supported by the circumstance that a corresponding shape of the spermatozoa is frequently met with in animals very far removed, indeed quite different, from each other. The variety of form in the spermatic elements is the more striking, because the female generative elements, throughout the animal creation, are distinguished by a uniform developement.\nMost of the spermatozoa have a slender, linear body, either filiform throughout, or swollen and enlarged at one end, which for convenience we designate the anterior end. This swollen extremity is differently developed, and frequently grown into a peculiar independent part, as, for instance, into a head or body, from which the other thin and longer part is extended as a whiplike tail. Various other forms of the spermatozoa cannot, however, well be reduced to this type, or at least only by the assumption that the filiform body is abridged in its longitudinal axis, to compensate for which it afterwards increases much in width and thickness. Hence the short dense thick corpuscles of a different shape, which are occasionally found in the genuine semen instead of the filiform spermatozoa. The size of the spermatozoa, like the size of all the elementary constituents of the animal body, is only very slight. It is only in a few cases that it exceeds the length of aline, a much shorter dimension being however much more general.\nLet us now trace the different histological formations of the semen, according to form and connexion in the principal groups in the animal creation.\nMan. \u2014 In man (in which the spermatozoa (fig. 323.) are composed of head and tail), as indeed generally in the whole division of the Vertebrata, the size* does not often amount to more than at the outside\n* We always refer in our measurements to Parisian lines ; a millim. = 0.443 of a Paris line.","page":474},{"file":"p0475.txt","language":"en","ocr_en":"SEMEN.\n475\nOf this by far the greatest part is occupied by the filiform tail. For the anterior body there hardly remains more than \u2014f\" to The body is rather flattened on the sides, so as to represent the shape of an almond. Viewing it from the surface {fig. 323. a), it looks like an oval disc, the longitudinal diameter of which exceeds the greatest width by\nFig. 323.\nA\tB\nSpermatozoa of Man.\nA, viewed on the surface ; b, viewed edgeways.\nabout one half, and which extends itself towards the posterior part into the filiform caudal appendix. The anterior extremity of the body is usually rather pointed, almost like the lower part of a pear or the point of an egg. If the body is situated on its edge {fig. 323. b), it resembles a short rod, rather pointed towards the anterior part, the transverse diameter of which measures about from one half to one third of the greatest transverse diameter of the lateral surface. The tail is cylindrical, thin at the posterior part, and prolonged into a very fine point, which can only be perceived .by the application of the highest magnifying power. At its anterior part, on the other hand, the double outline can distinctly be traced. But the thickness even here is always less than the thickness of the body.\nMammalia.\u2014The spermatozoa of the Mammalia have quite a similar form, but frequently a more considerable size. The genus Mus, the smallest mammals, remarkable to state, are distinguished in the latter respect. The length in Mus decumanus amounts to in Mus musculus -A/\",\u2018in Hypudacus arvalis, Sciurus, Talpa J/\", in Plecotus auritus, Cercopithecus ruber\tIn many other cases,\u2014 in Canis,\nFelis, Erinaceus, Lepus, Cervus, &c., the length of the seminal fibres is about the same as in man. But even then the body is generally of a considerable size ; as, for instance, in Sciurus, Cervus, and Lepus, where it measures 2^\u00f6'///5 as also in Talpa. The size of the body in a rat amounts even to -rgV'//. The difference, however, is frequently less considerable. In Canis, Rhinolophus, Hypudacus, Mus musculus, &c., the body only measures -f\", and even still less in the horse and cat.\nThe form of the body varies extremely*; all, however, exhibit parts corresponding to those of the spermatozoa of man. The fundamental form likewise is always that of a\n* Vid. R. Wagner\u2019s Icon. Physiolog. Table I. Elements of Physiology, p. 13.\nflattened oval. The spermatozoa of the monkey tribe are very similar to those of man ; likewise those of the cat, in which the body has a similar inverted oval shape ; as also those of the hedgehog. The body of the spermatozoa in the mole, as also in the horse, is uniformly rounded off at both extremities. In the Rhinolophus it presents the same regular form, but at its anterior extremity it seems to be furnished with a short and thin appendix, resembling a point. In other mammalia the posterior extremity of the body, which is in connexion with the tail, is the narrower one, whilst the free anterior end appears to be rounded off) or even to be more or less flattened. If the anterior extremity decreases gradually, the body assumes the usual egg form (Cervus, Lepus), whilst it exhibits more the shape of a pear in cases where that extremity is rounded off\u201c (Canis, Sciurus).\nThe width of the body, as well as the lateral flattening off, likewise increases with the enlargement of the longitudinal diameter. Its extreme developement is reached, as it seems, in Sciurus {fig. 324.). Here the body is very\nFig. 324.\nSpermatozoa of the Squirrel ( Sciurus vulgaris).\n. Viewed in different aspects.\nexpanded and thin, like a fine, transparent leaf. The lateral surfaces are hollowed out, like a spoon, or shovel. The margins, or edges, however, do not participate in this. They appear, especially at the anterior end, much thickened.\nAnother very remarkable form is seen in the body of the spermatozoa of the Murid\u00e6. It is attached to the anterior end of the caudal appendix, like the blade of a knife, but in such a manner that the tail, when viewing the body on the surface, is not situated as usual in the central longitudinal axis of the body, but passes over into one of the lateral margins. It might almost give rise to the conjecture that the one lateral half of the bod)7 had arrived at its full developement, whilst the other had dwindled away and been lost. In fact, the whole appearance of the body seems to justify the assumption of such a non-sym-metrical kind of developement. At the point which usually corresponds to the centre of the body, the lateral part, distinguished by its thickness, is prolonged into the tail. The thickness gradually decreases towards the upper extremity, which is bent in an arched manner, presenting a convexity towards that","page":475},{"file":"p0476.txt","language":"en","ocr_en":"SEMEN.\n476\nmargin of the body which projects at the posterior part into an obtuse angle. In the rat {fig. 325. a) the body is very long, but narrow in proportion, and bent like\nFig. 325.\nA. Spermatozoa of the Rat ; B, of the common Mouse.\na sabre at the anterior extremity. The body of the spermatozoa of the domestic mouse is shorter, and may be compared to a bent bistoury. The anterior end, however, is likewise drawn out into a short point, which in the field mouse is very slightly developed. The differences in the caudal appendages of the spermatozoa among the mammalia may be reduced to mere differences in length and thickness. In all of them the anterior part attached to the body distinguishes itself from the posterior part by its thickness, but not always to the same extent. Wherever the spermatozoa distinguish themselves by their length, the tail is likewise proportionably thick.\nDujardin* occasionally observed in the spermatozoa of men, at the commencement of the tail part, a small irregularly shaped protuberance, which K\u00f6lliker (who had likewise observed this in the semen of rabbits)\n* Annal, des Sciences, 1837, t. vii. p. 291.\nsupposes to be a mere temporary phenomenon\u2014 only a phenomenon of developement \u2014and that it subsequently disappears, whilst its adhesive matter is expended in the prolongation of the tail. This assumption likewise appears to us possible, although it is remarkable that such swellings or protuberances are so rarely met with, and, therefore, certainly cannot be considered as constant associates of the developement. We have only observed a few cases of this description, and that principally in the semen of rabbits. The swellings, which in their physical condition, especially in their refracting power, coincide entirely with the anterior body, have generally a globular shape, but exhibit otherwise many differences in size and position. They are found sometimes at the commencement of the tail part, sometimes rather remote from it. It appeared to us as if the respective appendages were formed less by a swelling of the tail fibre, than by a peculiar enclosing matter. It seemed to us, at least in a single spermatozoon, as if the tail could be clearly distinguished in the interior like a peculiar fibre. Further investigations on this subject are still necessary.\nThe spermatozoa of the mammalia generally lie very irregularly and confusedly. At times, however, they are grouped together (as we have especially found in the rat, the guinea pig, and rabbit, and as others have likewise observed in men) in very regular fascicles or bundles, which are formed by the bodies of the spermatozoa adhering by their lateral surfaces, as may be often observed with the blood globules.* It is uncertain, however, whether this group-like association of the spermatozoa is dependent, like that of the blood globules, on definite physical processes.\nThe developement of the spermatozoa takes place, among the mammalia in the interior of vesicle-shaped globules, which fill up the separate little canals of the testicles in great quantity. Kolliker has traced this mode of developement first of all in the guinea pig (which is very convenient for these investigations) ; likewise in the domestic mouse ; but has subsequently, after more extensive researches, determined that the mode of developement in all the mammalia is the same. These developing vesicles have pretty uniformly a size of about\tbut intermixed\nwith them there are frequently found vesicles of a smaller and of a larger diameter (to tF\u00f6///)-Taken from a fresh dead body, and when examined without being treated with water or any other agent, they are as clear as glass, possessing a delicate contour, and perfectly homogeneous contents. The latter, however, coagulates very readily, assuming thereby a granular quality ; but this we cannot consider as its natural condition.\nMost of these vesicles are free within the little seminal canals {fig. 326. a, b, c). They are frequently surrounded by a cellular enclosure,\n* Yide Wagner, leones Physiolog. tab. 1. fig. 2. Elements of Physiology, p. 10. fig. 4.","page":476},{"file":"p0477.txt","language":"en","ocr_en":"SEMEN.\neither singly {fig.326. d) or in numbers of three four, six, or seven {fig. 326. e). A more con-\nFig. 326.\nAB\tC\tD\nDeveloping Vesicles of the Spermatozoa from the Testicles of the Dog.\nsiderable number of them in one common cyst is unusual ; but they may, according to K'\u00f6l-liker's statement, amount to twenty. The size of the cyst naturally depends on the number and state of developement of the vesicles it encloses. Ordinarily it amounts to about\ni ///\ti ///\n10 0\t8 O _ *\nOn pursuing the genesis of the vesicles of developement, it will be found that they are produced in the interior of cells, according to the law of endogenous formation. The various circumstances which present themselves during the microscopical analysis support the probability of this opinion. It is certainly often difficult to determine whether an individual vesicle is destined for the production of other cells (tochter-Zellen), or immediately for the formation of a spermatozoon. But we shall see presently that the daughter cells are furnished with the same capacities as the free vesicles of developement ; they are like them in every respect, and justify the inference of a perfect identity with them. Wherever, therefore, we find these free vesicles of developement, they have, in our opinion, likewise been produced in the interior of other cellular formations, and have only become free by the dissolution of the former. The real process of formation of the spermatozoa in the interior of the vesicles of developement cannot be reached by our observation. The spermatozoon does not possess at its commencement those sharp, distinct contours\u2014that great refracting power, which afterwards so much distinguish it. Like a slight linear shadow it is seen lying in the interior {fig. 327. a, b) ; in addition to which it\nFig. 327.\nA 1\tB\tC\tD\nSpermatozoa of the Dog in the interior of the developing Cell.\nis covered by the granules, which are so readily deposited from the liquid part of the con-\n477\ntents. It is only gradually that it assumes a distinct appearance. At first the body only is seen, being recognisable by its specific form. The tail becomes visible subsequently. The entire spermatozoon lies in a curved shape close to the wall of the vesicle, until it has reached its full developement, when it becomes free by the bursting of the vesicle of developement. Sometimes {fig. 327. c,d) individual vesicles may be seen, from which the tail of a spermatozoon is projecting, whilst the body is still situated in the interior. The vesicle of developement generally retains, however, its original round shape, even when the spermatozoon has reached its perfect developement, and begins to stretch itself. Angular vesicles of developement, which occur so frequently in other animals, probably never occur here. It is only in rare cases {fig. 327. d) that the vesicle extends itself into a thin tail-like appendix, which then encloses the posterior part of a spermatozoon, and which is evidently only produced by the stretching of the latter. A law, which K'olliker first pronounced as correct, may here be enumerated, viz. that only one single spermatozoon, and never a greater number, is developed in each vesicle of developement.\nThe formation of the spermatozoa takes place in exactly the same way in the vesicles of developement, even in those cases where the latter have not become free, but remained enveloped by their mother cells. The spermatozoa, in this case, are not, however, immediately set free by the dissolution of the vesicles of developement ; but they arrive, first of all, in the cavity of the external cyst. The number of the enclosed spermatozoa therefore depends on the number of the enclosed vesicles of developement, a single fibre only being formed in each vesicle. The presence of several spermatozoa in the interior of a vesicle, therefore, affords us an immediate proof, that the latter histologically possesses the function of a mother cell, and is not itself the vesicle of developement.\nBut likewise in this case the process terminates with the dissolution of the cyst that surrounds the spermatozoa, and which prevented their becoming free immediately after the dissolution of the vesicle of developement.\nAccording to analogy with other animals* it is very probable that the above mentioned association of groups of the spermatozoa into fascicles is caused by the longer persistency of the vesicles of developement in the interior of a common mother cell. At all events, such an occurrence is traceable in almost all other cases in which a similar association in groups takes place; and it also happens among the mammalia, to judge from the fact, that a delicate cyst-like enclosure is often perceived at the circumference of the bundles.\nAves. \u2014 The spermatozoa of birds possess uniformly, instead of the short oval and flattened body which distinguishes them in mammalia, a body of a long and slender","page":477},{"file":"p0478.txt","language":"en","ocr_en":"478\tSEMEIS.\nshape, which gradually passes off into the posterior tail-like portion. The body, in most birds prolonged into a cylinder, is distin-\nFig. 328.\nSpermatozoa of the Cock (Gallus domesticus).\nguished by a greater thickness from the thin and filiform tail, which is twice its length (fig.\n328.). In other instances, how-Fig. 329. ever, it makes a number of spiral\nt twists, generally four, which make it look like a corkscrew. The anterior end, in that case, is generally pointed, and the posterior end is gradually extended into a long and straight tail (fig- 329.). The latter form is generally peculiar to the singing birds, and, indeed, an exclusive characteristic of them, enabling us, even by this circumstance, to detect the Picarii of Nitzsch from the true birds of song. Birds of the genera Coracias, Ca-i primulgus, Alcedo, at all events,\nI show this corkscrew form as little I as those of the genera Cuculus,\nI Picus, &c. ; whilst the birds of the raven tribe exhibit this same ! characteristic in common with the singing birds.\nThe number of separate twistings or turnings of the body, and their distance from each other, is different, however, in the several families and genera of singing birds. Among the thrushes, for instance, the spiral is very extended, and almost undulating, whilst the numerous twinings pass into one another at an obtuse angle. The twistings are less in number (from 4 to 5), in the Lanius (the Shrike) ; they are very narrow, and almost acutely angular, whilst they are at a greater distance from each other, among the Finches, where their number is still less (3 to 4). The upper windings are, in most cases, the most considerable, and likewise the most constant, whilst the lower become continually slighter, extending themselves sometimes (especially in Turdus, and likewise occasionally in Fringilla) throughout Sperma- the greatest part of the tail ex-tozoon of tremity of the spermatozoon. The Fringilla iength anc[ thickness of the tail, Spmus.\tjjjg number and arrangement\nof the windings, is subject to many changes and fluctuations among the several genera. It is particularly strong and rigid among the Fringillidae, the spermatozoa of which (as in Fringilla coelebs, the Chaffinch) attain sometimes a length of \\,,r\u2019, whilst in other cases they are much shorter (in Fr. Spinus == ff\", F. Canaria ff\", F. domestica ff\"). The tail part of the spermatozoa of the Lanid\u00e6 is, on the other hand, very short and fine, its length scarcely measures\t\u2014-gf\", of\nwhich about\t\u2014Tot,'\" goes to the anterior\nspiral body. The spermatozoa of Oriolus are only slightly larger. Among the Thrushes the length is about f/\", of which the anterior spiral body occupies quite one third. The same is the case among most other singing birds, as Sturnus, Hirundo, Parus, Alauda, Arthus, Certhia, &c. Motacilla and Emberza have spermatozoa of Sylvia (Ph\u0153nicurus vibilatrix) and Saxicola of . Among the last-mentioned genera, the spermatozoa form by their shape a kind of approach to the corresponding formations of the Fringilla, whilst the spermatozoa of others remind us more of these formations in the thrushes and the Lanid\u00e6. In other words, the formations just alluded to form a medium between the latter mentioned birds and the Fringilla.\nThe spermatozoa with a simple cylindrical body are much more uniform in size and shape, and differ from each other chiefly as regards the length of the tail, very little as to the length of the body.\nThe body generally measures from ffas'\"\u2014 (Picus, Falco, Columba, Gallus, Pavo, Anas, &c.), but seldom less (in Vanellus and Cuculus = ji/'). The tail is very thin, and can usually only be traced to its termination with difficulty. The anterior part, which is connected with the body, is but little distinguished from the posterior, and is always without any remarkable thickening. Its length is always more considerable than the length of the body, the entire fibre generally measuring\tand rarely less (Va-\nnellus, Cuculus) or more (Gallus, Columba).\nIt is an interesting fact that the difference of form of the spermatozoa in birds is associated with a difference in the manner in which they adhere to each other. Those which have a simple cylindrical body, are constantly dispersed about in the canals of the testicles without any order, whilst the spermatozoa of the singing birds are generally met with in regular bundles. The spermatozoa in each of these bundles, as in the mammalia, lie together in parallel lines, and with their tails all in the same direction. It is only in their passage through the vas deferens that the bundles gradually lose their regular connexion.\nThe genesis of the spermatozoa of birds, is essentially the same as among the mammalia. Their proportions are, however, much more distinct, and therefore more easy to trace. The examination of the domestic fowl is much to be recommended in this respect ; some time ago we described","page":478},{"file":"p0479.txt","language":"en","ocr_en":"SEMEN.\t479\nthe clevelopement of the spermatozoa of this bird.* The vesicles of developement, in this instance, have a size of\trio'\"\u2019 They\nare as clear as glass when in a fresh state, and the spermatozoon in the interior can very readily be observed. At the commencement they are globular. Subsequently the shape becomes more irregular ; sometimes it assumes that of a pear, until finally the enclosure bursts (which generally takes place at the sharp extremity), when the spermatozoon makes its exit with the tail end first ( fig. 330.).\nFig. 330.\nSpermatozoa of the Cock partly enclosed by the Cell of Developement.\nFor some time afterwards, the remainder of the vesicle of developement may be seen adhering to the separate spermatozoa.\nAll the cells of developement, however, are not free. We often find large cystiform globules, enclosing a number of three, four, eight, twelve, or sixteen cells'of developement, much more frequently than among the mammalia; these generally have a diameter of Too\u2014Vo\u2014-so'\"' But the persistency of these mother cells does not hinder the developement of the spermatozoa in any way. The enclosed cells of developement are equally as capable of producing these formations as the free ones, as one may readily convince oneself by observation through the microscope (fig. 33].). On the destruction\nFig. 331.\nA Mother Cell from the Cock, with three Spermatozoa still enclosed in their Cells of Developement.\nof the membrane of the cells of developement, the spermatozoa get into the interior of the cysts {fig. 332.), where they lie together often in a great number, but never\n* Lehrbuch der Physiol. 3d edit. \u00a7 18. S. 27.\nin regular fascicular groups. Finally, this cyst also gets dissolved, without, however,\nFig. 332.\nA Mother Cell from the Cock, with Spermatozoa free in its interior.\nhaving changed its shape in any remarkable way previously. The spermatozoa common to each cyst, however, remain together for a time, being connected by means of the tough albuminous contents of the mother cell. Thus, at least, we feel inclined to explain the occurrence of irregular groups of spermatozoa, which, kept together by one common cement, not unfrequently occur in the semen of the cock.\nAccording to our observation, the developement of the spermatozoa of the woodpecker and of the pigeon takes place in precisely the same manner; and this may be said likewise of singing birds.* The cells of developement of the latter are however still more rarely to be met with free, and are perhaps always enclosed by mother cells. The number of the enclosed cells is generally very considerable (\u00c4.333.).\nFig. 333.\nCyst of the House Sparrow, with enclosed Cells of of Developement.\nThe formation of the spermatozoa in the interior of the individual vesicles of developement is likewise very difficult to be traced, principally because the contents of the latter coagulate very readily, thus covering the spermatozoa, and rendering them indistinct. We have, however, succeeded several times in observing the spermatozoa in the house sparrow in the interior of their cells of formation (fig. 334.). It certainly requires some practice to discover the windings of the body between the granules of the contents, the\n* Vide R. Wagner\u2019s figures in M\u00fcller\u2019s Archiv. 1836, S. 225., in Fragm. zur Physiol, der Zeugung ; in Lehrbuch der Physiolog. \u00a7 17. S. 25. ; as also in the Icon. Phys. tab. I. fig. 5. (copied in the article, Entozoa, Vol. IL p. 112.), which however, in consequence of our recent researches, require some correction.","page":479},{"file":"p0480.txt","language":"en","ocr_en":"480\tSEMEN.\nmore so as the characteristic spiral twistings have not yet assumed that distinctness and\nFig. 334.\nCells of Developement with Spermatozoa of the House Sparrow.\nregularity, which they subsequently attain. The presence of the spermatozoa can only be proved with certainty, when they have become free, after the dissolution of their formative cells, the mother cyst still continuing to encircle them. Thus we may also explain the former conjecture of one of us, R. Wagner, who thought that the spermatozoa of the singing birds had their origin immediately in the interior of the large cysts.\nThe spermatozoa of the singing birds do not however lie together irregularly in the interior of these cysts, as in the cock, the pigeon, &c.,but are associated in very definite fascicles, as already described. We are ignorant as to the cause of this arrangement. The number and grouping of the cells of developement in the interior of the cysts do not present any remarkable differences from those in the cock, &c., although the spermatozoa of the latter are constantly devoid of such a regular arrangement. The spermatozoa of the singing birds likewise remain enclosed for some time by the membrane of the mother cysts. At the commencement they lie with reverted tails close to the interior wall of the cysts, which then assumes an oval form {fig. 335.). Subsequently the tail ends of\nFig. 335.\nMother Cell with a Bundle of Spermatozoa from Fringilla domestica.\nthe spermatozoa remove themselves further and further from the anterior bodies. The cyst bursts where the points of the tails are situated, and the bundles, which are still covered at the anterior end by the remains of the cyst, as if by a cap, then assume the shape of a retort, or of a knee-shaped bent cylinder. Even in cases in which the spermatozoa have perfectly separated themselves {fig. 336.), this remainder of the former cyst can generally be traced. We may also see very distinctly a tough albuminous substance between the individual spermatozoa, from which the tail ends project freely.\nThese proportions experience a small modification in those singing birds, in which the\nFig. 336.\nA Bundle of Spermatozoa from Fringilla ccelebs.\ntails of the spermatozoa are shorter than among the Lanid\u00e6. The cysts here retain almost entirely their original form, or do not enlarge to any extent {fig. 337.). The\nFig. 337.\nBundle of Spermatozoa in the interior of a Cyst of Lanins.\nspermatozoa in this case lie quite straight in the cyst from the commencement, and subsequently pierce the posterior end of it with their tails.\nReptilia. \u2014 The spermatozoa of the rep-tilia possess the same shape as those of birds; that is to say, an oblong cylindrical body, and a very fine hair-like tail.\nNo great differences present themselves in the form of these elements among the rep-","page":480},{"file":"p0481.txt","language":"en","ocr_en":"481\nSEMEN.\ntilia with scales. Lizards, snakes, and tortoises uniformly possess, like most birds, a simple and straight body (fig. 338.), which, however, is occasionally rather pointed towards the anterior part. This occurs, for instance, in the snakes. The only difference consists in the difference of breadth of body and tail. In the snakes (Coluber), in which the\nFig. 338.\tFig. 339.\nformation, which is assumed to be seated on the body lengthwise, and which is said to be bent in a zig-zig manner to the right and left. It is true that this fibre is frequently only seen to rise on one side of the spermatozoon, and in a shape which would encourage the conjecture just now alluded to (fig. 340.);\nFig. 340.\nFart of Spermatozoon of Triton.\na, body of the spermatozoon ; b, spiral windings of the delicate tail.\nSpermatozoa of Lacerta Spermatozoon of Rana agilis.\ttemporaria.\nspermatozoa measure about\tthe\tlength\nof the body amounts to only\t;\tin the\nlizards (Lacerta), on the other hand, in which the spermatozoa are smaller (^o'\"\u2014sV^) about\nThe differences of the form of the spermatozoa are however much greater in the group of the Batrachia, which likewise distinguish themselves in other respects by various deviating circumstances. A staff-like body with a very thin and proportionately short tail characterise the spermatozoa of Rana and Bufo (fig. 339.). The length of the spermatozoa here amounts to about \u2014-fa'\", of which the body occupies more than the anterior third. Among the Salamanders the body is likewise cylindrical, but much longer (\u2022s*ff'//), bent in the shape of a sabre, and thickest at its posterior end.* Towards the anterior part it becomes gradually thinner, and (in Salamandra at least) furnished at the point with a very small globular knob. The tail is likewise of a considerable length. In the anterior part, which passes into the body, it possesses a not inconsiderable thickness. Towards the posterior part it becomes finer and thinner, until at last it can only be traced with difficulty. The end of the tail is, however, not straight, nor curved like the anterior part, but turned up in a remarkable manner, and wound in very numerous narrow spirals round the commencing part of the tail, and even round the body. At least so we may explain the peculiar structure of the spermatozoa of Salamandra, and in this we agree with V. Siebold.j- Others, especially French naturalists, as, for instance, Pouchet, merely suppose the slender fibre, which is so twisted round, to be the contour of a ridge-like\n* Yide copies in R. Wagner; Fragment. Tab. II.\nf Froriep\u2019s Neuen Notizen, vol. ii. S. 281. No. xl.\nVOL. IV.\nbut in other cases the twistings are so distinct that they are not to be denied. We are of opinion that, whenever the tail has been lying only on one side of the spermatozoon, a partial twisting off has taken place. This notched appearance may be attributed to the tail fibre retaining its spiral twistings. It is, however, remarkable that the tail never moves further from the trunk of the body, constantly maintaining only a certain distance from it. We do not venture to decide the cause of this, yet we cannot see in it a positive proof of the correctness of Pouchefs view.\nThe length of the spermatozoa is very considerable. From the anterior point of the body down to the region where the tail bends itself, they measure in the Salamander , in Triton even \\f\". The spermatozoa of the Proteus seem to possess a still greater length, according to an imperfect statement of Valentin.*\nFig. 341.\nSpermatozoa of Bombinator igneus.\nThe spermatozoa in Bombinator igneus (fig. 341.) are of a structure quite similar to those of the Salamander, only smaller. The body of the former is staff-shaped, tolerably long, and getting thinner towards both ends. The point is again rather enlarged, and flat-\n* Repertorium fur Anat. &c. 1841, S. 356.\nI I","page":481},{"file":"p0482.txt","language":"en","ocr_en":"482\tSEMEN.\ntened. The posterior end is continued into the tail, which latter is tolerably thick, and almost straight at its commencement. It gradually, however, assumes a very thin appearance, becoming a very attenuated hair-like appendix, which exhibits the same spiral windings that occur among the Salamanders. The length of the spermatozoa, as far down as where the tail bends itself, amounts to \u25a0S11S\"/\u2014 50\nAnother very singular form of spermatozoa is met with in Pelobates fuscus. The spermatozoa measure\tThere is no boundary\nperceptible between the body and tail part, but one half of the spermatozoon distinguishes itself from the other by a considerable thickness. Both, however, gradually pass into one another. The thicker part exhibits from its commencement a number (generally eight) of spiral windings, which increase in size towards the anterior free end (fig. 342.). The anterior\npig. 342.\nSpermatozoa of Pelobates fuscus.\nend itself does not however participate in this formation. It is of a more delicate quality, paler, and has a constant vibrating motion, which gives to it a varying form. It generally appears to be wound in an undulating manner.\nA fascicular group of the spermatozoa is only found among the Reptilia in Batra-chians ; Bombinator, however, forming an exception. In the latter, as well as in the scaly Reptilia, the spermatozoa lie confusedly together. In the latter instances we can readily trace their production in the interior of separate solitary cells of developement ; as, for instance, in Anguis fragilis, or Bombinator igneus. The cells of developement of the latter animal (which to the number of two or four are enclosed b}r a mother cell, when in the earlier stages of developement) measure in a developed state about\tAt\nfirst, when the spermatozoon forms itself in the interior of these cells, it lies curled up close to the wall. Subsequently the fibre stretches itself, and changes the cell into an obtuse cylindrical enclosure, which finally bursts in the anterior and posterior part, to enable the spermatozoon to make its exit. The remains of\nthe cell of developement continue for a long time adhering to the body of the spermatozoa, generally in the centre, exhibiting the appearance of a comb-like appendix of a variable shape and size.\nThe formation of the spermatozoa in the interior of independent cells of developement likewise takes place in a similar manner in the Lacerta crocea. We have but rarely seen that the same cells are enveloped by larger cysts at the period of the production of the spermatozoa, which is commonly the case in former stages of the developement. The number of cells contained in one common cyst is generally only very small, seldom exceeding eight. The same is found, according to the\nFig. 343.\nCells of developement of Testudo gr\u0153ca with Spermatozoa and external cysts. (After K\u00f6lliker.')\nobservations of K\u00f6lliker, in Testudo gr\u00e6ca ; but the external cyst in this instance is said generally to persist for a longer period. The persistency of this enclosure is very general among the Batrachians, which distinguish themselves by the spermatozoa being associated in fasciculate groups. The number of the enclosed cells of developement here is generally a larger one (from ten to twenty). The developement of the spermatozoa in other respects does not, however, exhibit anything peculiar. They are formed as usual, separately in the enclosed cells of developement (fig. 344.). It is only afterwards,\nFig. 344.\nDeveloping cell of the Frog, with a Spermatozoon in its interior. (After K\u00f6lliker.')\nwhen these cells have been dissolved, that the spermatozoa get into the interior of the mother cyst, in which they congregate in fasciculate groups. By their so doing the cyst loses its original round shape, and assumes the form of a pear, until it bursts at the pointed extremity, and the tail-ends of the spermatozoa immediately project. The remains of the cyst continue recognisable for some time at the anterior end of each bundle. This is the case in the frog at any rate. In Pelobates, on the other hand, the filiform tails of the spermatozoa do not project from that part of the cylindrical enclosure which is burst, but the anterior vibrating body does so (fig. 345.).\nThe external cyst of the bundles of spermatozoa of the Salamander constantly retain its original globular shape, as the sperma-","page":482},{"file":"p0483.txt","language":"en","ocr_en":"SEMEN.\n483\ntozoa do not stretch but remain wrapped up.\tThe spermatozoa of Scymnus niceaensis {fig.\nIt is a remarkable sight to see the cyst burst- 349. a) are similar but rather longer, whilst\nFig. 345.\nA bundle of Spermatozoa of Pelobates.\ning on being treated with water. The whole mass of spermatozoa suddenly bursts forth, and only remain attached to each other by the heads, as if imbedded in one common substance. The separate fibres radiate in all directions, each being wrapped up in a spiral form.\nFishes. \u2014 In the class of fishes, the spermatozoa occur in two forms. The first is found throughout the osseous fishes, and also in Amphioxus. The other form is found among the Plagiostomes. In the former case the spermatozoa consist (fig. 346.) of a very small globular body (of -5^0'\"\u2014sno or even smaller, down to T^5^///, as in Perea fluviatilis), and an extraordinarily thin, hair-\nFig. 346.\nSpermatozoa of Perea fluviatilis.\nFig. 347.\nSpermatozoa of Cobitis fossilis.\nlike tail, which, however, possesses comparatively a very considerable length. Sometimes the body at the point of insertion of the tail has a small knotty appendix, as in Cobitis (fig. 347.), which gives to it a pear-like shape. The body in some genera is so small that it can hardly be perceived with any distinctness.\nThis also applies to the spermatozoa of Fi 348 Petromyzon, in which the form of \u00ae\u2018\t\u2019 the body is, however, different. In\nI\tP. marinus* the body is egg-shaped;\nI\tin P. fluviatilis (fig. 348.) staff-\nshaped. The length of the body in P. fluviatilis is\nThe spermatozoa among the Pla-giostome fishes are similarly formed Spermato- to those of the birds. They are long, zoon of filiform, and furnished with an an-Petromy- terior cylindrical body. In Scyllium tills ma~ Canicula the body is stiff and quite straight, and tapers at both ends. The tail is thin, and of an equal length to the body (*'\").\nFig. 349.\nA. Spermatozoa of\tb. Spermatozoon of\nScymnus nice\u00e6nsis.\tTorpedo Narce.\nthe body, instead of being straight, describes two long spiral windings. Four more narrow spiral windings are found round the body of the spermatozoa in Spinera acanthias, which measures whilst the length of the whole spermatozoon amounts to A similar number of spiral twistings are likewise seen in the body of the spermatozoa of most of the rays, in Torpedo narce (fig. 349. b), Raja rubus, &c. In Raja oxyrhynchus it is only the anterior part of the body which is spirally wound in a length of about -if\", whilst the posterior part is straight. The number of the windings is nevertheless, however, more considerable, viz. 7 or 8. The length of the whole spermatozoon amounts to\tChimera monstrosa like-\nwise exhibits these windings, notwithstanding the comparatively short body (T^//A) \u00b0f *ts spermatozoa, which have a length of \u00a3/\"\u2022 The number of windings is three.\nThe developement of the spermatozoa in fishes has as yet only been observed in the Plagiostomes. It is exactly the same as in frogs and birds, as the statements of Hallmann* lead us to infer. Almost all of the spermatozoa are united with one another in bundles. According to our researches in Torpedo Narce, the spermatozoa are produced sepa-\nFig. 350.\nCysts, with developing cells from the testicle of Torpedo Narce.\nrately in the cells of developement, which possess about the size of\tand which are\n* J. Muller, Untersuch, \u00fcber zu Eingewerde der Fische, Berl. 1845, S. 6.\t* M\u00fcller\u2019s Archiv., 1840, S. 467.\n1 1 2","page":483},{"file":"p0484.txt","language":"en","ocr_en":"484\nSEMEN.\nenclosed by a lesser or greater number of cyst-like mother cells (fig. 350.). The size of each of these cysts amounts to about wherever the number of the enclosed cells is small ; but in the reverse case it may increase to gV\". The cells of developement dissolve after the formation of the spermatozoa, and the latter then get into the interior of the cyst (flg. 351.). The spiral winding. 351.\nSpermatozoa in the interior of the cysts ( Toipedo Narce).\nings of the body seem to be still wanting at this stage, or, at least, not to be perfectly developed. If the number of spermatozoa is only small in one cyst, they never group together into a bundle, whilst this is constantly occurring in the reverse case (fig. 352.).\nFig. 352.\nBundle of Spermatozoa in a cyst ( Torpedo Narce).\nWe will not venture to decide, however, whether this difference is entirely attributable to the greater number of the cells of developement ; and we are the less inclined to do so, as we have already seen, when investigating the spermatozoa of birds, that, even with an equal number of the formations alluded to, the grouping of the spermatozoa in the interior of the cyst may be different. This much, however, is certain, that the number of the enclosed cells is not entirely without influence. The fact of the fascicles of spermatozoa always coinciding in one cyst with a greater number of the cells of developement, seems, at all events, to favour this conjecture.\nPrevious to the period of procreation, we also find, in the testicles of the osseous fishes, that the cells of developement are enclosed in the interior of larger cells (fig. 353.);\nbut here, as well as in the Lacerta, &c., the formation of the spermatozoa only takes place\nFig. 353.\nSpermatic cells from Cyprinus brama.\nsubsequently to the destruction of the cyst, and to the consequent independence of the cells of developement. We infer this from the circumstance that we have never seen in them any real bundles of spermatozoa. The statement of K\u00f6lliker that the spermatozoa of Ara-phioxus develope themselves from little cells (of t\u00f6W\" \u2014 t W'0> which lie together in groups of from six to twenty-five, also seems to support the correctness of our conjecture. Each of such groups appears to us to be the brood of a single mother cell. The mother cells themselves, however, are of such a small size, that the formation of such brood in their interior is not to be traced or perceived. It can only be seen that these cells gradually lose their round shape, and that they assume a pear, or spindle-like form. This, unquestionably, is merely the consequence of the endogenous developement of a spermatozoon, which gradually stretches itself, thereby causing (as in Gallus, Rana, &c.) the change of shape of the external enclosure.\nThus much of the proportions of form, and of the mode of developement of the spermatozoa among the Vertebrata. We have treated this subject somewhat elaborately, partly 'because the spermatozoa of these animals are those which may be most frequently obtained for observation,\u2014partly also because it is in them that the stages of developement can be better traced and recognised. We have invariably met with in them a common type, not merely in the external shape, but also in the mode of developement of the spermatozoa ; and these are circumstances which will be of importance to us in interpreting the stages of developement of the spermatozoa in the lower animals, in which they are as yet enveloped in great obscurity.\nMollusca. \u2014Among the Invertebrata, the division of the Mollusca uniformly possesses (as in the Vertebrata) filiform spermatozoa, which are enlarged at the anterior extremity. This anterior extremity does not, however, every where form a particular division, as a body, distinct from the posterior thinner part or tail. On the contrary, the one passes in many cases so gradually into the other, that it is impossible to determine the boundary between the two. The tail then appears to be a mere pointed continuation of the anterior enlarged part. The two thus distinct forms of spermatozoa are, however, again united with one another in various ways.","page":484},{"file":"p0485.txt","language":"en","ocr_en":"SEMEN.\n485\nFig. 354.\tCephalopoda.\u2014 In the Ce-\nphalopods we meet with the former form of spermatozoa with a distinct body and a thin and long hair-like tail, as among the scaly reptilia, &c. The body is cylindrical, or staff-shaped, in the spermatozoa of Octopus vulgaris (fig. 354.), which have a length of of which xi-g'\" belongs to the anterior body.\nThe spermatozoain Sepiola are shorter, and furnished with a body which measures\nThe developement of these spermatozoa occurs just as in birds, according to K'6lliker. The separate spermatozoa may be perceived very distinctly in the interior of their cells of developement. The fascicular grouping is wanting, although the spermatozoa remain enclosed for some time by the mother cells.\nThese fibres in the Cepha-lopods are, however, surrounded in their passage through the vas deferens by peculiar sack-like enclosures or Sperma-tophores, which are formed from the secretions of the gland contained within the walls of that channel. These enclosures gradually assume a very strange complicated structure, which we have only become acquainted with, within a recent period, through the excellent researches of Milne Edwards.* They assume the shape of cylindrical bags of a not inconsiderable size, so that they may readily be perceived with the naked eye. They contain at the posterior extremity a peculiar apparatus (besides the Spermatozoa, which are accumulated at the anterior thicker end), which is distinguished by a particular mechanism adapted for the expulsion of the seminal liquor.\nGasteropoda.\u2014The spermatozoa of the Gas-teropods exhibit, only in rare cases, as it seems,\nSpermatozoon of Octopus vulgaris.\nFig. 355.\n9 Q\nSpermatozoa : A, of Patella ; b, of Chiton.\na similar form to those of the Cepbalopods. This is the case, for instance, in Chiton and\n* Annales des Sciences Nat. 1842, tome xvii. p. 335.\nPatella (fig. 355.). The spermatozoa of the former consist of thin delicate fibres\tthe\nanterior body of which has an oblong shape, measuring about \u00efi\u00ef\u00ef/\". The body in Chiton is broader, almost pear-shaped, and of a more considerable size (^fa/\"). Similar cer-caria-like spermatozoa are possessed by Ha-lyotis and Bermetus, as also by Trochus and Paludina impura. The strict distinction between body and tail is, however, wanting in most of the other Gasteropods. The spermatozoa then have a filiform shape, and increase gradually in thickness from the posterior, pointed, towards the anterior end. The head or cephalic end is flattened. It is thus, for instance, in Carinaria ; also among the Nudibranchiata, Hypobranchiata, Pomato-branchiata, and Pteropods. At the same time the spermatozoon usually exhibits a number of light spiral windings, which diminish uniformly from the anterior to the posterior end (fig. 356. a). In Paludina vivipara (which,\nFig. 356.\nSpermatozoa, A, of Doris ; b, of Paludina vivipara.\nfrom the form of the spermatozoa, likewise belongs to this description, although the thinner tail part is distinguished by a greater length) the spiral windings are closer, as among the singing birds, and confined to the anterior body only (fig. 356. b). The spermatozoa of most of the other species of this genus possess quite a different form. In Turbo, Buccinum, Purpura, they are simply filiform, and equally pointed towards both ends. In Turbo they measure\t\u2014-\u00a3o\"\\ in Thedys,\nAplysia in Pleurobranchia Meckelii even &C.\nThe spermatozoa of pulmonary Gasteropods are usually still larger, extending to V\", as in Helix. As in the Nudibranchiata, they likewise become gradually enlarged towards the anterior part, but not flattened at the cephalic end, being, on the contrary, furnished with a short point (in Helix of with an appendix, which must be viewed as a peculiar form of body (fig. 357.). The same is thickest at the posterior part, thicker than the body, and gradually gets thinner towards the end. In most cases (Helix, Arion,\ni i 3","page":485},{"file":"p0486.txt","language":"en","ocr_en":"486\nSEMEN.\nClausilia, &c.), it exhibits two easy spiral windings, almost in the form of an S. Some\nFig. 357.\nSpermatozoon of Helix pomatia.\neasy spiral windings are also not unfrequently observed at the enlarged body.\nThe mode of formation of these spermatozoa can usually be traced without any great difficulty. It usually takes place in the same way as in the animals already described, as proved by K\u00f6lliker's excellent researches. Even in the Gasteropods we may observe the deve-lopement of the spermatozoa in the interior of particular vesicles. The arrangement of these parts only exhibits some deviation.\nIn Helix or Clausilia, in which the stages of this mode of developement can best be observed among our native snails, we meet with in the interior of the testicle, besides the developed spermatozoa, numerous larger and smaller aggregations of vesicles (in number varying from ten to forty), which are seated on the external surface of a round or oval globule (fig. 358.), which is in diameter\nOn a nearer research, it will be found that this globule is not a cell, as one might suppose at first sight, but merely a mass of a\nFig. 358.\nGroup of vesicles from the testicle of Helix pomatia.\ntough substance, in which a number of small brown granules are embedded, exhibiting a great similarity with the yolk molecules from the eggs of Helix. There is no external enclosure around this globule. The peripheral vesicles or cells, which adhere to it fre-\nquently in an irregular manner, generally measure\tbut are sometimes larger,\nto the extent of\tand above it. In\nthe interior of these cells we meet again with vesicular formations, generally measuring 2^///* The contents of these vesicles coagulate on being treated with water, &c., into a fine granular mass, exhibiting sometimes a simple or double granule of extraordinary size. The number of the enclosed vesicles, which evidently were produced in an endogenous way, is usually very small, mostly 1 or 2, more rarely 3, 4, or 6.\nThe developement of the spermatozoa takes place in the interior of these last-mentioned vesicles (fig- 359.). According to the\nFig. 359.\nSpermatozoon of Helix pomatia in the interior of its developing cell. (After K\u00f6lliker.')\nobservations of K\u00f6lliker, the head is produced first, being at first of a less regular, unwieldy shape. The tail is formed subsequently, attaching itself in spiral windings to the internal surface of the cell wall. On the spermatozoa being sufficiently developed, the vesicle of developement is dissolved, and the spermatozoa get into the cavity of the external cell (fig. 360.). Here they may usually\nFig. 360.\nSpermatozoa of Helix pomatia in the interior of their mother cells.\nbe perceived with great distinctness, whilst they can but rarely be distinguished in the interior of the real cells of developement.\nAt first the mother cells retain their original round form, even after the reception of the spermatozoa. They soon, however, on the windings of the fibres being stretched, extend themselves lengthwise, and assume an elliptical or pyriform shape. At a still later period the cell pushes forward (at the point where the heads of the spermatozoa are situated) a long pedicle-formed process, which contains the anterior extremity of the spermatozoa (fig. 361.). The point of this process or continuation constantly remains connected with the central globule of the former mass of vesicles, whilst the posterior belly-like part of the cell removes itself further and further from it. The same attachment takes place afterwards with the heads of the spermatozoa, on their being projected from the anterior end of this process, which usually happens soon. At this period the mass of vesicles reminds us","page":486},{"file":"p0487.txt","language":"en","ocr_en":"SEMEN.\n487\nstrongly, owing to its shape, of a group of vorticeil\u00e6 {fig. 362.).\nFig. 361.\nFig. 362.\nSpermatozoa of Helix po- A group of Spermatozoa\nmatia at their extrusion of Helix pomatia,\nfrom the mother cell.\tpartially protruded\nfrom the mother cell.\nAs soon as the heads of the spermatozoa have projected, the remainder of the mother cell lengthens itself, and becomes a delicate cylindrical envelope. These remains still adhere to the spermatozoa when completely extended, exhibiting the appearance of a couple of larger or smaller knobs on the tail : the same thing occurs in the spermatozoa of the frog.\nThis mode of developement is not changed by the presence of a greater number of spermatozoa in the interior of the mother cell. All the difference that may be seen is, that one spermatozoon comes forth rather earlier than another. The free spermatozoa are, however, by no means distributed without order over the surface of the central globule to which they still adhere. On the contrary, they are grouped together into one common fasciculate mass, in the same manner as we have already described in the singing birds. This circumstance is remarkable, because it shows us that the formation of a bundle of spermatozoa is not occasioned everywhere by the same means, and therefore does not always justify the inference of the persistence of an enclosing cell.\nA separation of the bundles of spermatozoa happens in Helix : the central globule (which forms the common cement that holds together the individual spermatozoa, in the same way as the tough albuminous mass in the cysts of the singing birds) gradually passes away.\nThe developement of the group of vesicles in Helix is very interesting and important. It is at once apparent that the same has originated from the brood of a single, originally simple, cell, and that through a continual endogenous increase. _ Our researches have afforded us the immediate proof of the truth of this, confirming, at the same time, the conjecture of K\u00f6lliJcer ; viz. that the primitive spermatic cells are the same formations which have been described as epithelial cells of the follicles of the testicle. In the interior of these cells, the contents of which consist of a brownish granular homogeneous substance, a certain number of vesi-\ncles are gradually produced, which continually increase in an endogenous manner, until the bursting of the mother cell, when the daughter cells deposit themselves around the globular remainder of the cellular contents {fig. 363.).\nFig. 363.\nFormation of groups of vesicles around the epithelial cells of the testicle in Helix pomatia.\nThe developement of the spermatozoa in the other Gasteropods is similar to that described, although not in all cases so distinct as in Helix. The endogenous formation of the spermatozoa can only with difficulty be perceived in Lyma, Lymnaeus, &c. ; it would rather appear as if they were produced by immediate growth from vesicular elements. The general rule is, that they are united with each other into groups, in which, however, the interior central globule is sometimes wanting (as in Cyclobranchiata, in Turbo, Euccinum, &c.) ; but this does not change in any way the developement and mode of grouping together of the spermatozoa. We have also, in this instance, in the united vesicles of a group, unquestionably only the brood of a common mother cell, which group may have enlarged after the destruction of the external membrane that surrounded it. The only difference would consist, in the circumstance that the entire contents of the mother cell are employed for the structure of the daughter cells, leaving no remainder, which perhaps might induce a more firm connection of the separate vesicles in the shape of a round mass.\nAcephala. \u2014 In comparison u'ith the variety in the form of the spermatozoa among the Gasteropods, we meet with but slight differences in the class of the Acephala, at least among the Lamellibranehiates.* The spermatozoa of these Mollusca consist of delicate fibres of about in length, the anterior end of which supports a short and distinct body of Fm 364 variable size (from -\u00f6W\" \u2014 *\t*W\") (fig- 364.). This body\n|| is usually (as in Unio, Cyclas, Clavagella) cylindrical ; in other cases (for instance in Mytilus, Pholas) pear-shaped.\nRespecting the formation of these fibres we only know K'\u00f4l-liker\u2019s opinion of it, viz. that they are produced in bundles from round cellular masses, and through an apparent prolongation of the vesicles ; as, for in-Spermatozoon stancej jn Chiton, &c. : our ex-\nmo\" amination of Unio was not calculated to give us an insight into it.\n* VideV. Siebold in M\u00fcller\u2019s Archiv. 1837, S. 381.\nI I 4","page":487},{"file":"p0488.txt","language":"en","ocr_en":"SEMEN.\n488\nTunicata.\u2014Among the Tunicata the Ascidia possess spermatozoa quite similar to those of the Lamellibranchi-ates, having a distinct head of dif-erent shape and a slender tail. The size of the spermatozoa is, however, usually rather larger {fig. 365.); the head is usually T^/// \u2014-8Iq///, the tail fluctuating between ffi\" \u2014-\u00a3$/\" The spermatozoa seem to want a body in the Salp\u00e6, according to the observations of Spermatozoon of Phalluria Ko Hiker, monacha. (AfterKoll\u00efker.)\tThe endogenous\nformation of the spermatozoa in the Ascidia is as little distinct as among the Lamellibranchiata. It seems, also, with regard to the former, that the developing vesicles simply extend themselves into the spermatozoa. At a previous stage of deve-lopement, these vesicles are, however, contained (either singly or in a greater number) in the interior of cells.\nArticul\u00e2t a.\u2014In the second great division of the Invertebrate animals, among the Arthro-poda, the filiform shape of the spermatozoa, if indeed it occurs at all, is generally still more marked in its developement than in the Mollusca. The spermatozoa are long and slender fibres, which, perhaps in all cases, are deficient of a real, distinct, and separate body, being at the utmost only slightly enlarged at the anterior end. The spermatozoa of some few groups, however, differ from this, and exhibit so striking a form and arrangement that one can hardly at first recognise in them the genuine spermatic elements. The question, indeed, arises, whether these parts are really in all cases the developed spermatozoa, or whether they do not constitute mere stages of developement. We shall subsequently return to this question ; let the remark suffice for the present, that in some cases the circumstances observed seem to favour the latter hypothesis, Insecta.\u2014The spermatozoa among the hexapod insects are of great uniformity. They appear, without exception, as filiform fibres (fig. 366.), which are frequently distinguished by being extremely slender in proportion to their length (the latter exceeds V\" in Staphylinus, but is generally less ; in Culex ff\"; in Agrion Virgo ff''\u201461o///)* The anterior end is probably always rather thickened for a consider-ableextent,and thereby distinguished from the posterior pointed end of the fibre. Remarkable deviations from this fundamental shape occur but rarely, but are nevertheless not entirely wanting. We may mention, for instance, that a peculiar angular appendix is found in the spermatozoa of the Locustinae at the anterior end of the body, this appendix being formed of two short crura, which converge\nand pass into one towards the anterior part, like the head of an arrow.\nFig. 366.\nSpermatozoa of an Insect.\nThe spermatozoa of the Hexapods are developed in the same endogenous manner, as among the Vertebrata. This process may very easily be observed. The vesicles of developement, which measure pretty uniformly, when in a developed state, ^f\" (they are smaller in manyDiptera, Culex (^f\"), Musca,\nFig. 367.\nCysts, with developing vesicles, from the testicle oj Staphylinus cyaneus.\n&c.), are in a variable, generally, however, in considerable number (twenty, thirty, forty), enveloped by larger cysts (fig. 367.) These cysts or enveloping cells frequently attain the size of ff\" (Carabus, Staphylinus, Locusta, &c.), and they are evidently the mother cells of the enclosed vesicles. In the upper division of the testicle, the\nFig. 365.","page":488},{"file":"p0489.txt","language":"en","ocr_en":"SEMEN.\n489\nnumber and size of the latter is generally much smaller than in the lower part. It follows, of course, that the size of the mother cells themselves is influenced by the size and number of their contents : wherever the number of the enclosed vesicles is small, the cyst never attains a considerable size. In Culex, for instance, it seldom exceeds\ni ///__i ///\nTOO\t75\t\u2022\nThe vesicles surrounded by the cyst are as clear as glass, and, when uninjured, contain an entirely homogeneous material, which, however, appears granulated on being treated with water, and then also it sometimes forms a\nwhich case the vesicles of developement form loose groups, as in Amphioxus.\nFig. 370.\nFig. 368.\nDeveloping cells of the Spermatozoa of Culex.\nlarge nucleus-like body in their interior. In each of these vesicles, as V. Siebold* has shown, a single spermatozoon is usually produced (fig. 368.). It attaches itself in numerous windings to the inner surface of the cell wall, until it has reached its full developement. In the mean time the vesicle loses its original round shape, becoming stretched, and assuming the most various forms (fig. 369.). At last the vesicle bursts at some place, and allows the spermatozoa to come forth. ( Fig. 370.)\nThe spermatozoa having thus become free, group themselves together into regular bundles, still enclosed by the mother cell of the vesicle of developement. This at least seems to be the case invariably wherever the cyst persists long enough. It, however, some-\nFig. 369.\nSpermatozoa in the interior of the vesicles of developement of Nepa cinerea.\ntimes disappears at an early period, as, for instance, according to Kollileer, in Musca, in\n* Uber die Spermatozoiden der Locustinen, A. a. o. S. 1.\nSpermatozoa partially expelled from the vesicles of developement of Nepa cinerea.\nThe bundles in many cases disperse as soon as the mother cells are destroyed. But it still more frequently occurs that these bundles survive the existence of the cyst, the remainder of which then covers for some time to come (as in the singing birds, &c.) the anterior end of the bundle in a cap-like form. (Instances\u2014Coleoptera, Neu-roptera, &c.) In this part, which is generally lengthened, the separate spermatozoa lie together in a remarkably dense manner, being almost united together into one common mass.\nIt is different, however, in most cases with the posterior division of the bundles (fig. 371. A.), where the separate fibres start away from each other. In this way the usual pear, club, or retort shape of the spermatozoa bundles is produced.* It is but rarely the case that the spermatozoa present, in their whole length, an arrangement similar to that which is usual at the anterior end. The whole bundle of spermatozoa then appears as (fig. 371. b) a homogeneous structure, and might\nFig. 371.\nBundles of Spermatozoa, A, from the testicle of Sta-phylinus erythropterus ; B, of St. cyaneus. (After Siebold.)\nreadily be taken for a single colossal spermatozoon, if the observation of the developement had not taught us otherwise. Of this, however, we may convince ourselves by ma-\n* We are inclined to regard as bundles of spermatozoa of this kind, those formations from the testicle of Paludina vivipara, which V. Siebold described as a second form of spermatozoa. Muller\u2019s Archiv. 1836, S. 246.","page":489},{"file":"p0490.txt","language":"en","ocr_en":"490\tSEMEN.\nnipulation, pressure, &c., whereby the separate constituent elements can be demonstrated. In Staphylinus cyaneus (fig. 371. b) these bundles are wrapped up into one roundish knot (excepting the anterior ones, which are still covered by the remains of the cysts) ; in Panorpa communis they have curled arrangement.\nIn many cases, several of such fibres join themselves lengthwise into one restiform mass, which is still covered in the interior of the testicles by a common gelatinous enclosure. This produces the long vermiform bodies, which are so frequently met with in the testicles of the butterflies, but which also occur in some few other insects, as in Diptera (e. g. in Scatopsis).\nIn their gradual advance through the vas deferens, the spermatozoa lose this mode of grouping;\u2014their bundles separate. In the place of 'this they are, however, very frequently enclosed in masses by peculiar baglike enclosures, the so-called Spermatophora*, such as we find in the spermatozoa of the Ce-phalopods, only of a much more simple structure. By the aid of these formations, the spermatozoa are transferred into the female generative organs. Formerly it was usual to look upon the remains of these bags as the torn-off generative organ of the male. The spermatophora of insects have usually the form of a pedunculated globule (for instance, in the Locustin\u00e6 and Lepidoptera). Through a series of transition-forms they reach ultimately the shape of a long thin cylinder, of which a striking example is afforded in Clivina Fossor. The spermatozoa lie either irregularly in the interior of the spermatophora, or united into regular bundles. This mode of grouping has an extremely elegant appearance in the Locustin\u00e6. The tails of the fibres join together on either side of a furrow, from which the several fibres start to the right and left like the barbs from the shaft of a feather. Spermatophora are wanting in many of the Hexapoda. Instead of them we sometimes find (as in Carab\u00e6a, Tittigoria, &c.) a number of long and rather broad bandlike transparent strings, which _ are frequently wound in the shape of a spiral, and, like the spermatophora, are also formed in the vas deferens of the male. These strings, on being treated with water, separate into a great number of spermatozoa, the separation taking place either gradually from the ends, or more suddenly in their whole extent. The entire mass thus proves itself to be one large seminal string, a formation which, in its whole quality, approximates very nearly to the second form of the seminal bundles from the interior of the testicles enumerated by us.\nThe cause of such an arrangement and grouping of the spermatozoa is equally as unknown to us as that of the formation of the bundles of spermatozoa in the cysts. Whether they are peculiar phenomena of at-\ntraction, or whether they are other relations caused by external influences and circumstances, we know not. We must therefore for the present be satisfied with a simple statement of the facts.\nAlthough, from the great uniformity of the spermatozoa in the class of Insects, we might reasonably expect a corresponding similarity in the other groups of the Arthropoda, observation teaches us that such is not the case.\nInstead of the filiform formations, which, however, are here the usual constituents of the seminal liquid, there are found in some cases quite peculiar bodies of a remarkable shape. The history of their de-velopement alone can prove that the elements alluded to are not, as one might perhaps suppose, morphologically different formations, but that they owe their origin to a mere modification in the application of the ordinary stages of developement. It can be proved that the bodies in question in most cases are immediately connected with the former stages of developement of the spermatozoa. Thus our conjecture (above expressed) gains in probability, that many of such-like little bodies are mere forms of developement of ordinary filiform spermatozoa. The following investigations, however, will afford us a confirmation of the truth of our conjecture : \u2014\nArachnida. \u2014 In the class of the Arachnida, the usual filiform appearance of the spermatozoa has only been observed among the scorpions. The spermatozoa of these animals are about -fe'\" long, and rather thickened at one end. They develope themselves, according to K\u00f6lliker, in the usual manner in the interior of vesicles, which are contained, in numbers, in a larger cyst-like cell.\nIn the Arane\u0153, on the other hand, which, owing to the difficulty of an anatomical examination, have hitherto but rarely been submitted to a careful inspection, the spermatozoa are said to present a very different shape. V. Siebold*, to whom we are indebted for the only statements regarding them, describes them as round or reni-form cellular bodies, on the interior wall of which a round or oblong nucleus is situated. We have also met with such corpuscles, and that in great quantity, in the testicles of the most different species of spiders ; we must however dispute the assumption of V. Siebold, viz. that such are the developed spermatozoa, since we have succeeded in discovering filiform bodies besides these formations, which former undoubtedly develope themselves from the latter, and are the real spermatozoa. These relations we have recognised most distinctly in Clubiona claus-traria. The contents of the testicles here consist of a large number of small round cells of-3i\u00f6///, in which a very perceptible nucleus is contained. The nucleus is at first round (fig. 372. a), but gradually elongates\n* Vid. Stein.\nLehrbuch der Vergluchenden Anatomie, \u00a7 544.","page":490},{"file":"p0491.txt","language":"en","ocr_en":"SEMEN.\n491\nitself, and then becomes a short, and generally curved, cylinder (b), one end of which\nFig. 372.\nSeminal cells in the testicles of Clubiona claustraria.\nis frequently club-shaped. The nucleus at the same time generally urges itself towards the outside, its point penetrating through the external cellular membrane. The projecting part of the nucleus generally appears like a protuberance at the margin of the cell, the greater part of it being still situated in the interior (c, i>). In some cases, however, it breaks forth in its whole length (e). It then looks like a peduncle-shaped appendix.\nWe have not been able to discover further stages of develope-Fig, 373. ment in the interior of the testicles ; but we have suc-\u00c7\\\t\\\\ ceeded in detecting, besides\nI\tthe already mentioned cor-\nI)\tII puscles, a number of dis-\n1/\tI\ttinct linear fibres of \u2014\nl\tI\t(fig. 373.) in the spoon-\nI\tj/\tshaped capsules on the pal-\nI\t1\tpi of the males, which, no\nJ\tJ\tdoubt, were developed sper-\n/\tmatozoa. The anterior half\n'\tof these was generally bent\nin an arched cylindrical form, and thicker than the posterior tail-like part. Very similar, only rather longer, Seminal fibres of\tseminal fibres are likewise\nClubiona.\tfound in the seminal capsules\nof the palpi in a species of\nTetragnathus.\nIt can hardly be doubted that these fibres have originated from the previously described spermatic cells. The changes of form to which the nucleus is subjected in the course of developement present a gradual approximation to this form of spermatozoa, at least to the form of the anterior thickened corpuscles, with which the nucleus moreover corresponds in its physical characters. In order to render the metamorphosis of the nucleus into spermatozoa complete, it certainly is necessary that the external cellular wall should disappear; but this is a general rule in the developement of spermatozoa, and probably also takes place here, although we cannot furnish any immediate proof of it. It must, however, appear remarkable that we have never met with developed spermatozoa in the testicles themselves. We could only trace in them cells of developement, formations which, besides the spermatozoa, also occur in the capsules of the palpi. The question might be asked whether this would not render the inference\njustifiable that the spermatozoa only attained their final developement at the latter spot, and therefore at a distance from the place of their formation. From our described observations we cannot yet venture to decide this question with certainty. The circumstance is, at all events, very remarkable, and would be the more so in case V. Siebold's statement that the cellular seminal corpuscles are to be met with even in the receptacula seminis of the female spiders, were to receive confirmation.\nIn our description of the developement of the spermatozoa in Clubiona we have left the question undetermined, whether they originate directly from a metamorphosis of the nucleus, or through endogenous formation in the interior of it. \u2014 We have not been able to arrive at any decisive result respecting it with regard to Clubiona, although the latter appeared to us more probable from analogy.\nOf some importance in this respect are our observations on the developement of the spermatozoa in a large species of Epeira. The seminal cells measure ( fig. 374. a)\tthe\nFig. 374.\nDevelopement of the spermatic cells of Epeira.\nnucleus which they contain\tThe cells\nare enclosed in larger cysts (ofy^\"__ff\") ;\nbut besides these there is also no want of individual solitary cells.\nThe most interesting circumstance connected with this is, that the spermatozoa are produced quite distinctly in the interior of the nucleus of the spermatic cells. At first they are lying (b) like a bent cylinder at the interior surface of the wall, so much bent that both ends nearly touch each other. We have never perceived a change of shape in the nucleus, nor does the same ever or any where penetrate beyond the cell. It constantly remains round, and in the interior of the cell, until it is dissolved, which takes place pretty rapidly after the formation of the spermatozoa. The spermatozoon now arrives in the cavity of the cell (c\u2014f), where it increases in size (to Tocr^O- It usually exhibits here some slight and irregular windings, which sometimes change the form of the cell into an oval. The spermatozoon only becomes free afterwards, when the membrane of the cell has disappeared. It is only if the external cyst happens to persist that the spermatozoa still remain enclosed for a time (h), but always in a greater number, which naturally is equal to the number of the cells formerly contained in","page":491},{"file":"p0492.txt","language":"en","ocr_en":"492\nSEMEN.\nit. A tail part we have, however, never been able to discover in the spermatozoa of Epeira. The form was uniformly cylindrical, and of a tolerable thickness, similar to the body in the spermatozoa of Clubiona.\nQuite the same mode of developement of the spermatozoa we have also found in one species of Theridimna. It can be traced that it does not deviate at all in the formation of its spermatozoa from other animals. But even the process of developement in Clubiona, which we have described, does not exhibit any very material differences, which is proved by the observation, instituted by us in a small Dysdera, as also in Tegenaria domestica. The mode of formation of the spermatozoa, in fact, in these instances, occupies almost the medium between the former two.\nIn Dysdera the spermatic cells containing the nucleus (fig. 375. a) measure only\nFig. 375.\nSpermatic cells of Dysdera.\nThey are round at first until the nucleus elongates itself, enlarges, and finally assumes a kidney form, the external cell taking on the same shape (b, c,d). One end of the nucleus not unfrequently projects outwards (e), but never in so striking a manner as in Clubiona. The same changes of shape are exhibited in the nucleus in the seminal cells of Tegenaria, which measure\tthey, however, never\nlose their original round shape in the course of the change.\nWe have not been able to discover filiform spermatozoa in the two last-mentioned spiders ; but we nevertheless believe that they likewise occur here, as in Clubiona.\nRespecting the spermatozoa of the Acarin\u00e6, we have as yet had but few observations ; it appears, however, from the statements o\u00b1 V. Siebold, that similar stages of developement take place as among the genuine Arane\u00e6. V. Siebold observed in the testicles of Ixodes ricinus a large number of rather long and large rods, which had an arched curvature, and were enlarged at one end in a clubbed shape. These rods were probably the developed spermatozoa, and of a similar nature to those we have found in Epeira. We do not venture to determine whether the same inference may be drawn with regard to the club-shaped corpuscles, which V. Siebold discovered in the Hydrachne\u00e6 and Gamase\u00e6. From the description given, however, viz. of these corpuscles enclosing an oblong spot in the enlarged end, and of their having been pro-\nduced by the metamorphosis of round nucleated cells, we would rather suppose that they were mere stages of developement of the seminal cells, similar, perhaps, to the pedunculated seminal corpuscles in Clubiona. In addition to this we may mention that Dr. Frey has communicated to us an observation, from which it appears that Hydrachna likewise possesses spermatozoa of a filiform shape.\nThe contents of the testicles in other Acarin\u00e6 (Trombidium, Zetea, Oribatea, Hop-lophora, &c.), consist of small globules, which in Bdeila assume a cylindrical shape. We are inclined to consider such as the free nuclei of seminal cells. We, at least, believe we have seen in Phalangium that they were surrounded by a cellular vesicle.\nMyriapoda. \u2014 The remarkable spermatozoa of the Chilopoda, which appear either as cylindrical corpuscles when in a developed state (in Glomeris), or (as in lulus) as short conical formations with a rounded point, are, according to our observations, of the same nature as the foregoing.\nIn lulus terrestris, in which we have traced the developement of these parts through all phases, the primitive contents of the testicles consist of a great number of small round cells of t&\u00f6'\", containing a very clear nucleus (of about\twhich lies close to the cell wall,\nand is highly refracting (fig. 376. a). In the course of the developement, the nucleus en-\nFig. 376.\nSpermatic cells of lulus terrestris.\nlarges, and, in so doing, gradually converts itself into a short cone (b, c, d), which, with its point, extends beyond the surface of the cell. For a time the cell continues to be attached to the surface, until it dissolves, rendering the seminal corpuscles free (fig. 377.). The basal part of the developed\nFig. 377.\nSpermatozoa of lulus terrestris.\nspermatozoa has a diameter of ^ and is rather protuberant and enlarged at the edges. The height of the spermatozoa is always less than the width, generally by one half.\nOn comparing the phenomenon in the formation of these bodies with the first changes of the nucleus in Clubiona, the analogy between the two will clearly be seen. The relative value only of the two is changed. The corresponding conditions in Clubiona form mere stages of transition necessary for further developement, whilst the developement in lulus does not proceed further than the stage described.","page":492},{"file":"p0493.txt","language":"en","ocr_en":"SEMEN.\n493\nThe differences in the form and develope-ment of the spermatozoa of lulus fabu-losus are very interesting. The formation of these parts does not confine itself, as in lulus terrestris, to the mere metamorphosis of the nucleus into spermatozoa. Previous to the latter projecting over the external surface, the cell membrane gets enlarged on the opposite side (fig. 378. a, b, c) into a corpuscle, which assumes the\nFig. 378.\nSpermatic cells of lulus fabulosus.\nsame shape as the nucleus. The spermatozoa in I. fabulosus do not, therefore, consist in one short cone, but rather in two such formations (fig. 378. d, e, f), which are turned towards each other with their broad surfaces partially touching. One of these is not unfrequently distinguished from the other by a more considerable size. In a developed state, when the original cell membrane, in which the cone was formerly imbedded, has disappeared, the two parts sometimes separate, each having a perfect resemblance to the spermatozoa of I. terrestris.\nV. Siebold, to whom we are indebted for the first accurate statement respecting the Chilo-pods*, was not acquainted with the developed forms of these parts in I. fabulosus. He describes as such the stages of developement of the spermatic cells illustrated by us iny?g. 378. AtoE, comparing them with the shape of snuff-boxes, in which the lower surface is much thickened, whilst the upper surface contains in the centre a roundish nucleus.\nThe spermatozoa of the Chilognatha f are filiform and of a very considerable length and thickness ; e. g. in Geophilus, where they measure\tTowards one end they gradually\nbecome finer, and usually rather undulating or spiral, particularly at the anterior thick part. In Geophilus these fibres are rolled up separately into one ring-like curl ; in Scolopendra, on the other hand, they are straight, and united in small numbers into string-like bundles. Nothing certain is as yet known respecting the developement of these fibres ; but, with V. Siebold, we think it very probable that they originate from the larger cells (measuring in Geophilus J/', in Lithobius \u2014 f/\"), which contain a single, double, or treble nucleus (of Too'\" \u2014 ihs\")\ta nucleolus, and\n* M\u00fcller\u2019s Archiv. 1841, S. 13.\nf See Stein. M\u00fcller\u2019s Archiv. 1842, S. 258.\nwhich are found in great quantity in the testicles. From analogy we may infer that it is in the nucleus within the vesicle that the fibres are produced. The association of the groups of spermatozoa in fascicles in Lithobius has, however, no intimate connection with the manner of their production, because the enclosed nuclei never equal in number the united fibres enclosed in one bundle. It is probably the result of a subsequent transition (like the formation of the seminal fibrous strings in the Hexapods).\nCrustacea.\u2014Among the Crustacea, to which we now proceed, we likewise meet with, as in the Myriapoda and Arachnida, many varying forms of the seminal elements. The most remarkable are the so-called radiating cells of the Decapods*, small, strangely formed corpuscles of a variable shape (and generally of a size of\twhich\nowe their origin to a metamorphosis of spermatic cells containing nuclei. By the different developement of the nucleus and cell membrane (fig. 379. a, b, c, d), they are\nFig. 379.\nRadiating cells of Grapsus marmoratus (a), Pa-gurus oculatus (b, c), and Pisa tetraodon (d). (After K\u00f6lliker.)\nusually divided into two portions of different shape and size, and are furnished at the boundary between the two with delicate and fibrous rays, which vary in number from one to four, but are generally three ; but this is effected in such a manner that the rays constantly remain connected with the division produced from the metamorphosis of the original cell membrane, and never with the nucleus part.\nThese radiating cells are produced from the original simple seminal cells in the following manner : \u2014 The nucleus (as in Clu-biona and the Iulides) gradually projects further and further towards the outside, thereby metamorphosing itself into a roundish (in Calappa, Hyas, Stenorhynchus, Scyllarus, Astacus fluviatilis, &c.) or spiral (in Cran-gon, Pisa, Galathea, Pagurus) appendix of the cell wall, which frequently enlarges itself considerably, especially in Pagurus, where it reaches \u2022\u00a3/\". In the mean time, the cell membrane has likewise undergone some changes. It either gets flattened more or less (Pal\u00e6mon, Stenorhynchus, Pica, Calappa), or it lengthens itself into a cylindrical corpuscle (Galathea, Astacus marinus). It is sometimes the case, however, that it retains its original round form (Ilia, Pilumnus, Pagurus, Astacus fluviatilis).\nAt the anterior end of this last corpuscle, where the part containing the nucleus adheres to it, the rays now gradually dart forth,\n* Vide the numerous and accurate statements and illustrations of K\u00f6lliker.","page":493},{"file":"p0494.txt","language":"en","ocr_en":"494\tSEMEN.\nat regular intervals, which give to the corpuscle sometimes an angular appearance, as in Pisa. The length of the rays holds an inverse ratio to the size of the cells, and is, in most cases, either equal to, or double, their diameter.\nThe peculiar form of these seminal elements naturally provokes the question, whether they really represent the developed spermatozoa, or whether they are not perhaps mere phases of developement. The relation in which they stand to the simple spermatic cells suggests a conjecture of this kind ; and the more so as the rays attached to them already present the greatest similarity with the usual filiform spermatozoa. We regret to say, that we are not yet in a position to decide this question with perfect certainty. From various observations, however, the latter assumption gains in probability. K\u00f6lliker has observed (in Calappa) that the adhering nucleus is lost at a later period ; further, that in Portunus corru-gatus, the cell membrane gradually gets very much contracted ; whilst, on the other hand, the rays considerably lengthen themselves. If we consider, in addition to this, that radiated cells are found in Ilia Nucleus, which (y?g.380.)\nFis. 380.\nA cell with rays from Ilia Nucleus. (After K\u00f6lliker.')\npossess extraordinarily long fibres on a very small body; that finally in Pagurus, as it seems, the rays perfectly sever themselves from the corpuscles; that, at all events, developed radiating cells, without rays, are often found in the latter, it must induce us to share Kolliker\u2019s opinion, that the radiating cells, at this stage of their formation, are not yet perfected ; but that they are more likely to be instrumental in the developement of ordinary spermatozoa. Such spermatozoa, however (if we except the genus Mysis, which is certainly unjustly divided from the Decapoda), have not yet been proved to exist in any of the animals belonging to this class. K\u00f6lliker has succeeded only in Dronia Kumphii in discovering a great number of fine pale fibres of\tin the lowest part of the\nvas deferens, which probably owe their origin to the rays of the seminal corpuscles, which, however, are much shorter than those fibres, hardly measuring above\nSuch a negative result can, however, the less determine our judgment on the nature of the radiating cells, since the observations, which one of us (R. Leuckart, together with Dr. Frey) has instituted, with regard to the developement of the spermatozoa in Mysis, have brought the question pretty nearly to a decision. V. Siebold was already acquainted with the filiform spermatozoa in this crawfish, which are distinguished by their great length (of ').\nThis animal possesses the more interest for\nus, owing to the remarkable mode of formation of the spermatozoa, which is extremely similar to the developement of the radiating cells in the other Decapods.\nThe primitive seminal cells in Mysis appear as round pale nucleated vesicles, of about x\u00e8o/// in diameter (fig. 381.). In the course of their\nFig. 381.\nDevelopement of the seminal corpuscles in Mysis.\n(After Frey and Leuckart.)\nfurther developement, a small wart-like process (b) rises somewhere on this vesicle, which gradually lengthens itself (c, d), and grows into a long cylindrical tube of ffi\". The nucleus does not participate, in any way, in this metamorphosis. It retains its original form, and remains at its original place in the interior of the seminal cell, which is seated on the cylindrical staff like a globular appendix.\nIn spite of their rather peculiar shape, we do not hesitate to pronounce these seminal elements of Mysis as parallels of the radiating cells of the other Decapods. Excepting the rays, we can find no material difference between them. That the wall of the cell is not immediately metamorphosed into the cylindrical body, is equally as little material as the circumstance that the nucleus remains without change, and does not project outwards. Indeed, we also find the same relation in the radiating cells of Astacus marinus (fig. 382.), where the nucleus likewise remains in the interior of the cylindrical radiated corpuscle.\nTo judge from their form, these seminal corpuscles would have most resemblance to the radiated cells of Pagurus ; but, according to Kolliker\u2019s observations, it would appear that the long cylindrical appendix has originated\nFig. 382.\nRadiating cells of Astacus marinus (After K\u00f6lliker.)\nfrom the metamorphosis of the cellular nucleus.\nThe nucleus in Mysis, together with the sorrounding head-shaped part of the seminal corpuscle, is subsequently destroyed, the same as K\u00f6lliker has found it in Calappa. There merely remains, then, a simple long cylinder (fig. 383. a), which represents the radiating corpuscle. The formation of the spermatozoa takes place in the interior of this cylinder : they consist of long linear fibres, which lie in","page":494},{"file":"p0495.txt","language":"en","ocr_en":"SEMEN.\t495\nit lengthwise, until they perforate the external enclosure at one end, and now gradu-\nFig. 383.\nDevelopement of the Spermatozoa in Mysis.\n( After Frey and Leuckart.')\nally project outwards (b, c). The number of the fibres thus formed is generally limited to one. We have, however, seen cylinders which contained three or four (c).\nThe formation of the spermatozoa in the radiating cells of the other Decapods, in our opinion, takes place in the same manner. Judging from analogy with Mysis, at least, we cannot share the conjecture of Kolliker, that the rays would simply drop off and change into spermatozoa. It appears to us much more probable that they are produced, as in Mysis, in the interior of the cell, and that the growing out of rays is merely a secondary event, caused by the circumstance that the spermatozoa formed in the interior urge the external membrane forward with one end, and ultimately penetrate through it. The projection of the seminal fibres, in Mysis, from the cylinder, has indeed much the appearance of their growing out into a thin and long appendix.\nThus much respecting the remarkable seminal corpuscles of the Decapods. We must still, however, mention the circumstance that the radiating cells in the lower division of the testicles, or in the vas deferens, are generally still enclosed by peculiar spermatophora, like capsules, which possess a round or oval shape, and are often attached, by means of a solid peduncle, in great numbers, one behind another, to one common round or flat jelly-like mass.\nThe spermatozoa in the other orders of the Malacostraca, the Amphipoda, and Isopoda, are uniformly filiform. Their developement takes place in the usual way, without the intervention of radiated cells.\nThe length of the spermatozoa, in most cases, is very considerable : in Hvperia medu-sarum f\", in Iphimedia obesa in Jdotea tricuspidata ff\", in Gammarus Pulex\nThe thickness, on the other hand, is comparatively only slight, being most considerable in the centre, whence the fibre gets gradually thinner towards both ends. Kolliker describes, in the spermatozoa of Iphimedia and Hyperia, a thicker cylindrical and oval end, like a peculiar corpuscle. V. Siebold does the same with regard to Asellus aqua-ticus. We believe, however, that such an\nFig. 384.\nSpermatozoa of Gammarus Pulex.\nappendix {fig. 384.), or this so-called corpuscle, is merely the adhering remainder of the mother cell, from which the spermatozoa project. Of this we have convinced ourselves in Gammarus Pulex. It is certainly difficult to distinguish the seminal fibre in the interior of it, but it appears to us that our observations are sufficient to render doubtful the interpretation of Kolliker, when we consider that this corpuscle occupies so variable a position with respect to the fibre, now lying in the same line with it, and at other times passing into it at a larger or smaller angle, quite in the same manner that we have observed in the cylinder of the seminal corpuscle of Mysis.\nThe variable shape of the body, which Kolliker describes in Hyperia, and which we have also found, although less remarkably so, in Gammarus Pulex, might also speak in favour of our opinion.\nThe formation of the seminal fibres in the Oniscid\u0153, according to our observation, also takes place in the interior of transparent cells*, which reach\tand fill up by\ntheir number the sacs of the testicles. As soon as the developement of the spermatozoa has commenced in the interior, the cells grow to the extent of and in so doing assume an oval shape. The contents then usually become rather granular, but the windings of the transparent spermatozoa can nevertheless be recognised now and then. The vesicular seminal elements of Gammarus Pulex, on the\n* The large egg-shaped corpuscles (of J/ O which possess, besides nucleus and nucleolus, dark granular contents, and which form the epithelium of the vas deferens, but which are wanting in the genuine seminal tubes, should not be confounded with these seminal cells. Similar cells, only smaller (ofabout2j^'\"), are likewise found in the spiders; but, although they occur in the seminal corpuscles of the palpi, they are not in any way connected with the production of the spermatozoa.","page":495},{"file":"p0496.txt","language":"en","ocr_en":"496\nSEMEN.\nother hand, are cell formations, which de-velope a seminal fibre in the interior of the enclosed nucleus.\nOf the same filiform shape, and probably also of the same mode of developement, are the seminal fibres of the Pychnogonides, which, according to an observation of K\u00f6lliker, measure upon an average about -\u00a3/\" in Pychno-gonum Bal\u00e6narum.\nEqually filiform and also pointed at both ends, are the developed spermatozoa of the\nFig. 385.\nDevelopement of the Spermatozoa in Chthamalus Philippii. (After K\u00f6lliker.')\nCirripeds, the size of which, in Chthamalus Philippii, amounts to about -f/\". They are produced from smaller nucleated cells (of -i-'\"\u2014-i-\"'), which would seem, from external appearances, simply to grow out into seminal fibres {fig. 385.). An exact research into the mode of their production is prevented by the smallness of the cells ; but we need the less hesitate in inferring the usual endogenous mode of formation, since we know how often spermatozoa, on liberating themselves from a mother cell, present, in a most deceiving manner, the appearance of vesicles that are growing out.\nLittle is as yet known respecting the spermatozoa of the Entomostraca. Here also, however, the usual filaments occur in the seminal liquid, in some instances. This may be proved in the genus Cypris, in which such formations can readily be traced.* * * \u00a7 They are of a considerable length (about 1'\"), and usually wrapped up in the shape of a reel. Such a form of the spermatozoa does not, however, seem to be the only one among the Entomostraca. V.Sieboldf, in Daphnia rec-tirostris, describes oblong semilunar spermatozoa, whilst Cyclopsina, and probably also AcanthocereusJ, possess small finely granular corpuscles of an oval shape, as the elements of the semen. Similar corpuscles one of us (R. Leuckart with Dr. Frey \u00a7,)\n* We beg to direct attention to the simultaneous appearance of eggs together with the spermatozoa in the same individual ; and therefore to the hermaphrodite condition of the genitals in Cypris.\n\u2022j- Vergleich : Anat. S. 483.\nt According to Sch\u00f6ller, in Wiegman\u2019s Archiv., 1846, Th. i. S. 367.\n\u00a7 Ibid. p. 135.\nhas discovered in Caligus. The production of these elements, which could be observed in the latter case, is the same as in lulus. They at first appear as roundish nuclei in the interior of the seminal cells, which have a size of\t\u2014a ho'\"- At this period the nuclei\nmeasure\t; they subsequently grow,\nchange their shape to an oval, and in so doing not unfrequently project outwards a little beyond the cell wall.\nVesicular seminal elements are also possessed by Branchipus*, and oblong cylindrical corpuscles by Staurosoma.f\nIn their passage through the vas deferens, the spermatozoa in Cyclopsina, as well as in the Cephalopoda, &c., are enclosed by one common jelly-like spermatophore. In some other cases, on the other hand (as in Onis-cus), the spermatozoa unite into long flat ribbon-like strings (of 1///), which present quite an uniform structure, betraying at the ends only that they are composed of separate seminal fibres.J\nAnnelida.\u2014The spermatozoa, in the division of the Annelida, also possess very generally a hair-like form, excepting among the Nematoda. They are thin delicate fibres, generally without any very considerable length (in Hirudo\tPlanaria varicosa gg\", in\nBranchiobdella, on the contrary, quite %'\"), which are either pointed towards the ends, or every where equally thick (in the Tre-matoda, Acanthocephala, and Cestoidea), or enlarged at one end.\nIn Lumbricus {fig. 386. a) the enlarged part is of an oblong cylindrical form ; in the Nemertin\u00e6 (b) and the branchiated Annelida,\nFig. 386.\nSpermatozoa of Lumbricus (a) ; of Nemertis Ehren-bergii (b) ; and Planaria verrucata (c). (After K\u00f6lliker.)\non the other hand, they are round or pear-shaped. In some few cases the spermatozoa among the Annelida exhibit some spiral twin-ings; as, for instance, in Planaria verrucata (c), Leptoplana atomata, and especially\n* Frey and Leuckart in Wagner\u2019s Zootomie, 2d edit. Part II. p. 259.\nf Will in Wiegman\u2019s Archiv., 1844, Th. I. S. 340.\nX Vide Siebold in Miiller\u2019s Archiv. 1836.","page":496},{"file":"p0497.txt","language":"en","ocr_en":"SEMEN.\n497\nin the Branchiobdella. Tn the latter, these windings are, however, confined to the anterior half ; but they are so close and numerous that they formerly gave rise to the erroneous opinion of one of us#, namely, that the fibres of this part were jointed or articulated.\nThese fibres are in all cases produced separately from small cells, containing nuclei (generally of T^///\u2014g\u00a3^///)> which lie together in round masses ; being generally situated on the circumference of a large central ball among the bristled worms and Hirudines, as among Fig. 387.\nDevelopement of the spermatozoa in Lumbricus.\nthe Helicin\u00e6 (flg. 387. a,). According to analogy with the higher animals the spermatozoa are also unquestionably produced in an endogenous way, and, as is shown by the observations o\u00a3 K\u00f6lliker f on the developement of the spermatozoa in Lumbricus and Distoma, in the interior of the nuclei. We cannot, however, trace the process of formation with decisive certainty owing to the smallness of the elements in question. The external appearance (b) leads us, however, to infer that the cellular formations grow out into a long fibre. The cells gradually assume a fusiform shape, but still remain united together in one group. It is the peripheric end. which seems to get extended in forming the spermatozoa. Wherever a central ball occurs, for instance, in Lumbricus and Hirudo, the group of cells at this stage of the developement presents a very pretty appearance. The spermatic fibres radiate towards all directions from the central ball, into which their thickened extremity is inserted; they have then made their exit in a still imperfect state (c). They soon, however, get grouped together into bundles, the points of the fibres gradually converging towards one common point (d) ; the central ball in the mean time gradually dissolves. Similar fasciculated groups are likewise seen in the spermatozoa of Annelids in most cases even where the central ball is wanting \u2014 in the Trematoda, &c. for instance. The same facts we have already noticed when speaking of the Gasteropoda. We then proved that the separate elements in the groups of cells originate through the continued en-\n* Wagner in M\u00fcller\u2019s Archiv. 1835, S. 222. f K\u00f6lliker, Die Bildung der Samenf\u00e4den, u. s. w. S. 37.\nVOL. IV.\ndogenous formation from one single, and at first simple, cell. It is easily traceable that the same takes place in the Annelida, when we compare the different constituents of the semen, for instance, in Lumbricus. Here, as in the Gasteropoda, we meet with numerous formations, which in one continued series of transitional developement lead to the form of groups of cells, taking their origin from one single nucleated cell containing some brownish granules. In the interior of this cell numerous daughter cells are produced, the number of which continually increases. Finally the wall of the mother cell bursts, the enclosed cells become free, and deposit themselves around the remainder of the cellular contents, which latter have not participated in the formation of the daughter cells.\nWhenever the central ball is wanting in the group of cells, the mother cell generally gets destroyed at an earlier period. This view is supported by an observation of K\u00f6lliker, from which it appears that the groups in Spio consist at first only of few and large cells, which subsequently increase in number whilst their size decreases. It is impossible, however, to draw a very strict boundary here. Even in. the former case the increase of the daughter cells frequently seems to take place after the membrane of the mother cell has been destroyed, which may also be seen in the Helicin\u00e6. In other cases the mother cell not only survives the endogenous formation of daughter cells, but also the process of the developement of the spermatozoa. We are at least led to this inference by the observations which we had the opportunity of making in some small species of TerebeTlaria from the North Sea, namely, that the bundles of spermatozoa are sometimes still enclosed by one common oval cyst.\nBryozoa.\u2014A similar series of phenomena we Fig. 388.\nSpermatic cells of Flustra carnosa; (a) still con~ tained in the mother cyst ; (b) partially free.\nfind in some Bryozoa (which would be perhaps Fig. 389,\nDevelopement of the spermatozoa of Flustra carnosa. (After K\u00f6lliker.)\nmost correctly classed among the Annelida), for instance, in Laguncula and Alcyonella*,\n* Vid. Yon Beneden in the Mem. de l\u2019Acad, de Bruxelles, tom. xv. and xviii.\nK K","page":497},{"file":"p0498.txt","language":"en","ocr_en":"498\tSEMEN.\nwhilst the formation of the spermatozoa' in others (for instance, in Flustra, Erisia, Bowerbankia) only commences when the separate cells of developement (b) have become free through the destruction of the large (\u25a0?&/\"\u2022\u2014cyst-like mother cell {fig. 388. a.). The spermatozoa even here, however, are produced by the apparent growing out of the small cells of developement (of jfco\"') containing nuclei (see^g. 389.). When developed they are linear and proportionately thick and long (in Flustra about and frequently, it seems, furnished with a roundish or oval corpuscle.\nRotifera\u2014The spermatozoa of the Rotifera, at least of Megalotrocha, have a similar pinlike form, if we may judge from the observation of K\u00f6lliker *, which is the only one before us, and this does not seem to be quite decisive. His statement, that these formations had partially been fixed in the interior of the cavity of the body, makes us at least look upon his observations with mistrust, and leads us to suppose that they have been confounded with the remarkable vibratile organs, which are certainly not spermatozoa. K\u00f6lliker\u2019s observation, however, is interesting, inasmuch as he also states that those fibres are apparently produced through the growing out of small solitary cells.\nSpermatophora have not yet been met with in the division of the Annelida. On the other hand, however, we have observed that the spermatozoa in some species of S\u00e6nuris (Tubifex) unite into transparent homogeneous strings (as in many insects) in their passage through the vas deferens. These formations have a cylindrical shape, almost vermicular, getting thinner towards both ends. They are also not unfrequently met with in the recepta-culum seminis of the female apparatus. A similar mode of grouping seems to take place with regard to the spermatozoa of the Hirudines, in the so-called secondary testicles. The spermatozoa of the Nematoda (excepting the paradoxical genus Pentastomum, in which we find the ordinary linear spermatozoa) possess very deviating shapes. They consist of a roundish or oval corpuscle of about and a short rigid peduncle, which projects more or less outwards, and has a varying thickness {fig. 390.). The spermatozoa in\nFig. 390.\nSpermatozoa of Strongylus auricularis. {After Reichert in Midler\u2019s Archiv. 1837. Tab. VI.)\nGordius appear in the shape of short rods without any corpuscles.\nWe cannot doubt that these seminal elements are developed spermatozoa, having sought in vain, and for a long time, for other forms of developement, and having found\n* Froriep\u2019s Neuen Notizen, S. 596.\nthe very same formations again, in a perfectly unchanged shape, in the female individuals. We must therefore characterise K\u00f6lliker\u2019s supposition of these corpuscles being mere stages of developement of seminal fibres, as one that cannot be relied upon.\nThe developement takes place in the same way as in lulus. At first we find simple cells containing nuclei, which, accordingto Reichert's researches, are produced in the interior of large mother cells * {fig. 391.). The nucleus Fig. 391,\nSpermatic cell of Ascaris acuminata, with four vesicles of developement, {After Reichert.)\nhas at first a roundish shape {fig. 392.), but gradually stretches itself more and more, and\ntFig. 392.\nDevelopement of the spermatozoa of Ascaris acuminata.\nprojects more or less outwards with its point, thus metamorphosing itself into the peduncle-like appendix of the spermatozoa, the body of which is formed from the persisting membrane of the seminal cell. This last circumstance, but which does not invariably occur, is the only distinction that can be found between the Nematoda and the Iulid\u00e6.\nRadiata. \u2014 Echinodermata. \u2014 The spermatozoa, in the division of the Echinodermata, possess, it seems throughout, a pin-like form {fig. 393.), with a small\nFig. 393.\n\u00ce\nSpermatozoon of Holothuria tubulosa.\nroundish body (of\tand a very slender\ntail appendix of about\t\u2014fo'\". It is only\nin x\u2019are cases (as Spatangus) that the body has an oblong form, and is rather pointed at the anterior end.\nThe developing cells of these spermatozoa are very small, and lie in groups, as in the Bryozoa, inclosed in large cyst-like mother cells. The developement of the spermatozoa undoubtedly takes place according to the usual mode, although it cannot be proved with certainty, and although the appearance\n* Muller\u2019s Archiv. 1847, S. 88.","page":498},{"file":"p0499.txt","language":"en","ocr_en":"SEMEN.\t499\nseems rather to indicate a gradual elongation of the cells. The spermatozoa lie together in bundles, either enclosed by the cysts or free.\nAcalephce and Anthozoa.\u2014The Aealeph\u00e6and Anthozoa exhibit quite a similar series ofphe-nomena. The bodies of the spermatozoa are usually round, frequently however, especially among the Medusae ( fig. 394-.), oblong, cy-\nFig. 394.\n9\nSpermatozoon of Pelagia, denticutata.\nlindroid. Little is as yet known respecting their developement. The spermatozoa have generally a fasciculated style of grouping together, and mostly so at a period when they are still enclosed by cyst-like cells. Previous to the maturity of the generative capacity, these cysts contain, as has been proved with regard to the Medusae, numerous small vesicles, which subsequently pass through apparent prolongation into spermatozoa.\nInfusoria. \u2014 The Infusoria are especially distinguished by the want of a sexual mode of propagation. There is no trace of either spermatozoa or ova to be discovered in them. Ehrenberg, it is true, describes in these animals particular organs of procreation, both male and female ; but there is no foundation for the assignment of such an import to these particular parts of their structure, it being altogether an arbitrary one. The proof of the existence of spermatozoa and ova \u2022\u2014 the * characteristic structures \u2014 is indispensably necessary to prove the embryo-preparing function of certain parts, and to justify their being interpreted as generative organs.\nGeneral conclusions respecting the morphology and developement of the spermatozoa. \u2014 A review of the description now lying before us, of the form and developement of the seminal elements in the several divisions of the animal kingdom, and of the mutual relations of the respective formations, must unavoidably lead us to claim for them a different morphological value.\nBy far the greater part of the spermatozoa, \u2014 all the so-called seminal fibres, which are distinguished by the linear form of the body,\u2014 are produced in an endogenous way, and that (with the exception of the spermatozoa in the Decapoda) separately in the interior of vesicular elements. K'\u00f4ll\u00efker* was the first who directed attention to the wide extension of this mode of production f, hav-\n* Die Bildung der Samenf\u00e4den.\nI The doubts which Reichert recently raised against the correctness of the statements and obser-\ning claimed it likewise for such animals, in which appearances are rather in favour of an immediate metamorphosis of the vesicles of developement into seminal fibres (by means of elongation, growing out, &c.). The laws of analogy certainly justify us in drawing the same inference as K'61/ilcer ; the more so, as observation has proved that many animals, the developement of whose spermatozoa was formerly accounted for by the latter methods, evidently also follow the endogenous type.\nIt is difficult to trace the intimate developement of the spermatozoa in the interior of these vesicles ; but it appears probable that it is brought about by the junction of molecular corpuscles, which join each other linearly, and which have been deposited from the contents of the vesicles. Indeed, such a mode of procedure does not seem to be at all singular in the history of developement of organic tissues. By saying this, we do not exactly mean to allude to the mode of formation of the muscular fibrils in the interior of the sarcolemma of a so-called primitive fasciculus, since at present we know too little about it; yet,we cannot help reminding our*readers of the process of lignification in the vegetable world, or of the production of the so-called spiral vessels, which essentially seem to be founded on a perfectly analogous deposit of a firm substance, from that which was at first fluid.\nThe decision of the question respecting the histological significance of the vesicles of developement is much more difficult. In many cases, especially when they are situated separately or in small numbers in the interior of the spermatic cells, they have evidently the value of nuclei. Whether this however is always and every where the case, as K'dllilcer supposes, we would not assert ; the less so because the appearance and the vesicular form of these structures do not by any means enable us to distinguish them properly from cells void of nuclei.\nBy the laws of analogy, we are, however, perhaps justified in forming a judgment on the nature of the respective elements even in such doubtful cases. We ourselves might perhaps even venture to pronounce that the vesicles of developement of the spermatozoa are in all cases nuclei. The unity in the mode of developement of the spermatozoa which would thus be established is certainly very attractive; but we dare not conceal it from ourselves that this inference from analogy is the less to be depended upon, since the genesis of the spermatozoa in the Decapoda furnishes us with a proof that the formation of these elements may also take place immediately in the interior of cells, without the nuclei at all participating in it. We are confirmed in this opinion from the circumstance that in many Decapoda, for instance in Mysis, it is not the cell itself in which the spermatozoa are produced. The cylindrical\nvations of K\u00f6lliker we certainly must consid\u00e9ras entirely unfounded.\nK K 2","page":499},{"file":"p0500.txt","language":"en","ocr_en":"500\nSEMEN.\nstaff, in the interior of which the spermatozoa are developed, is the produce of the metamorphosis of this cell ; a metamorphosis which here appears in its extreme form, but which in other cases is less striking, and may even be entirely wanting. And then it is the cell in its unchanged form which appears as the vesicle of developement of the spermatozoa.\nUnder such circumstances it might for the present be venturing too much to sever the mode of developement of the spermatozoa in the Decapoda, as a particular form, from the ordinary endogenous formation of these elements. We are not justified in so doing, until we have proved that in other animals mere nuclei exist as the mother cells of the spermatozoa. It is possible that such a proof may yet be established, indeed even probable, when we consider that there is also in other respects a difference in the formation of the seminal fibres between the Decapoda and other animals, inasmuch as the vesicles of developement in the former generally and almost constantly produce a greater number of spermatozoa, whilst in other animals they only produce a single fibre.\nAs a circumstance of subordinate import, which need not influence our judgment respecting the nature of the vesicles of developement, we may specify a difference in the histological characters of these parts, which certainly at first sight must appear very striking. We meet with them either in an independent free state, or separate, or enclosed in a variable number within cells, which themselves not unfrequently hang together in groups, or are even situated in a cyst-like enclosure. But all these differences result solely from a different developement and application of all the plastic capacities inherent in the cells. They are due to the occurrence of an endogenous multiplication, and are readily explained by the intimate unity and connection which this method of developement presupposes.\nThe formative elements of the semen appear to us in their primitive form as simple nucleated cells. But it is only rarely that they retain this original form. As a rule they present only the starting point of a series of metamorphoses, which essentially are limited to a new formation of nuclei, or even of perfect nucleated cells in the interior of the primitive spermatic cell : a new formation, which, however, not unfrequently occasions the destruction of the mother ceil.\nIt is not yet decided in all cases in what manner the formation of the daughter cells takes place, whether in the usual mode of endogenous cell formation, or by enclosure of portions of the contents. It seems, however, that the former mode of production is by far the more frequent one. Reichert has been the only one who has hitherto discovered a formation of daughter cells round portions of the contents (like the formation of cells in the minutely divided yolk) in the spermatic cells of the Nematoda. If such discovery should be confirmed \u2014 should it\neven have a greater extension \u2014 we may then further presume (as K\u00f6lliker already observes) that these two modes of developement are not essentially different from each other.\nThe description we have just now given may, at all events, be sufficient to prove of what a merely subordinate significance are these differences in the histological arrangements of the formative elements in the seminal fluid. By a series of intermediate stages, we can almost every where readily trace the connexion in which the arrangement of the vesicles of developement stands with the simple primitive spermatic cell. Such a relation, however, is not only interesting on account of its enabling us to recognise an internal typical structure and developement of the seminal contents, and that in spite of their external variety, but also because we thereby discover that the primitive form of the male procreative elements is precisely the same \u2014 namely, a simple cell \u2014 as that of the female generative product, which is designated \u201c the ovum.\u201d\nHaving thus, by our preceding researches, arrived at the result that the developement of the spermatozoa always and everywhere originates from the same primitive formation, namely, from the simple cell, another question now arises, viz. the question respecting the relation of this simple cell to the epithelial lining of the seminal tubes.\nThis claims our attention the more, as our conception of the epithelium, within a recent period, begins to be more and more indefinite, owing to the accumulation of observations, by which the so-termed epithelial cells of the glands have been proved to be mere vesicles of secretion, the workshops for the preparation or expulsion of the products of secretion.\nThe recognition of the connexion of the spermatic cells with the real epithelial cells is rendered very difficult by the various metamorphoses of the former in the tubuli seminiferi. Nevertheless, some observations that have been made may perhaps already justify the inference that the simple spermatic cells are, in many instances, at least, identical with the so-called epithelial cells of the seminal tubes.\nThis appears with particular distinctness in the Gasteropoda, in which Meckel* and K'6l-liker have already assumed such a relation, without, however, pronouncing it with that degree of certainty which our observations enable us to do. We may as readily convince ourselves of this fact in the Annelida, in Hirudo or Ascaris, as also in the Insects, Spiders, and Arthrostracans ; it being evident in all of them that the spermatic cells constitute the only vesicular contents of the testicles, and form, in their primitive shape, a complete epithelial layer, the elements of which frequently even assume a polygonal shape by close adaptation to each other.\n* Muller\u2019s Archiv. 1844.","page":500},{"file":"p0501.txt","language":"en","ocr_en":"SEMEN.\nThis connexion is, however, least distinct among the higher Vertebrate; in which, independently of the spermatic cells which exist free in the semen of the seminal canals, there likewise occurs a special and generally well developed stratum of epithelial cells, which are distinguished from the former by size and appearance. But this arrangement is only to be met with during the period of generative maturity. Previous to it, free spermatic cells do not exist, and the canals of the testicle have then uniform contents, consisting of small cells of of a line in diameter, in which one or two' small granules are contained. We have not been able to trace the history of the real seminal cells, but we do not consider it as altogether improbable that they are produced from the former epithelial cells, and most likely are developed in an endogenous manner. The possibility can certainly not be denied, that they may have been produced independently and free in the interior of the seminal canals. But even in this latter case it is unquestionable that the vesicle in which they develope themselves is furnished by- the epithelial cells and has formerly been contained in their interior. The difference even in this instance, therefore, would not be so very material, and might be reduced to a mere difference in the periods of formation. In both cases the seminal, cells might be assumed to be produced from the contents of the epithelial vesicles, either at a period when such contents are still contained in the interior of them, or after they have become free.\nOur preceding remarks respecting the histological relations of the seminal cells apply in an equal measure to all animals, and not merely to those the spermatozoa of which possess a linear form and are produced in the interior of the vesicles of developement. The Chilopoda, Acarina, Entomostraca, and Nematoda furnish us with sufficient proofs of this,\u2014proofs! which contradict the assumption of Kollbker *, that a linear form of spermatozoa is common to all animals. Although many of the differently-shaped seminal elements may, after a more accurate research, be proved to be mere forms of developement of the real spermatozoa, even this cannot be asserted with regard to all of them. These differently-shaped seminal elements are the very ones that here more particularly concern us ; we know that they differ in their developement from; the ordinary seminal fibres. They are solid massive corpuscles, which, as we have already shown, have been produced simply and immediately from a metamorphosis of nuclei.\nBut even here it is the nuclei of the seminal cells, which serve' for the developement of the spermatozoa. The whole difference consists in this, that the nuclei are metamorphosed altogether into the fructifying elements of the semen, whilst otherwise they produce the spermatozoa in the interior, they themselves\n501\ngetting dissolved when the latter are about to be liberated. The external cellular membrane which encloses these nuclei remains, however, without any immediate participation in the formation of the spermatozoa. It gets destroyed in the course of the developement, in order to enable the nuclei, which in the mean time have been converted into spermatozoa, to make their exit. This at least holds good in most of these cases, the Nematoda only being an exception. The membrane of the cells belonging to the metamorphosed nuclei, persists in the latter-named animals.\nAccording to this we have a threefold mode of developement of the spermatozoa, viz. : \u2014\u00ab\n1st. The cell membrane and nucleus of the formative vesicles convert themselves immediately into the spermatozoon.\n2d. The nucleus of the formative vesicles alone metamorphoses itself into the spermatozoon.\n3d. A new formation, which takes place iff the interior of the nucleus (or immediately in the cell cavity), performs the functions of a spermatozoon.\nOn comparing the spermatozoa developed in these different ways, we cannot deny that they have a different stage of developement in a morphological point of view. The spermatozoa resulting from endogenous formation are most highly developed ; they are the; produce of a perfectly new generative process,, whilst the- other forms of; spermatozoa owe-their origin to a persistency and further-developement of structures, which, first of all;,, were mere transitory elements, and were only of importance as the seat of that neoplastic process. Under such circumstances we may assume,, then, that all these forms of spermatozoa, according to the morphological relation in which they stand, are mere different stages of developement in one common continued series,\u2014mere variations of one thema,. in which the differences seen are not essen*, tialy but only of a . relative import. Taking into consideration this unity, we cannot agree to the objection that may possibly be made to us, as if we had described the spermatozoa (which, essentially and in fact, are identical formations) to have been pro\u00ab duced in different ways. The mutual relation of these differences is, in perfect unison with the laws of organic architecture, which eyery where (when a common plan is made the basis of a series of formations) exhibits the variety of the concrete form principally through- a variable developement and perfection of the ideal type.\nIt might not be without interest to re-5 fleet upon the important part which the nucleus plays in- the-formation of the spermatozoa, since it is an element which is usually only important for the formation of cells, and does not participate in their subsequent me, tamorphoses. This at least is the rule ; a rule, however, by no means without exception. We already know that in many cases the nucleus is important for the developement of certain parts ; we know that the nucleus;\nPage 63.","page":501},{"file":"p0502.txt","language":"en","ocr_en":"502\tSEMEN.\nin many glandular cells of the insects gradually assumes a remarkable ramified shape * ; and that it even converts itself in other cases into peculiar fibrous formations \u2014 into the so-called nuclear fibres ( Kernfasern ).f Still more remarkable is the metamorphosis of the nucleus in the developement of the so-called prickle or nettle organs \u2014 those interesting microscopical formations, which are so frequently imbedded in the skin of the lower animals (e. g. Polyps and Medusae), and which present so great a similarity to \u2022certain forms of the seminal fibres, that they were even taken for such by one of us on their first discovery. K'6lliker>s\\ observations, as well as our own more recent ones, instituted upon Hydra, convince us beyond doubt that it is the nuclei of cells which gradually metamorphose themselves into the capsules of the prickles, and which ultimately become free through the dissolution of the cell membrane surrounding them. The same genetic process therefore takes place here in every essential point of view, as that by which the formation of the spermatozoa in the Chilopoda is effected. But the developement of the prickles is never limited to this metamorphosis of the nucleus. There is formed at the same time in its interior a peculiar .linear or fibrous part, which however constantly enters into combination with the persistent external vesicle of the nuclei or with the capsule. Thus we may see that the formation of the prickles is closely connected with that scheme which we have laid down as a formula for the developement of the spermatozoa. It occupies the medium between the second and third mode of de-velopement of the spermatozoa established .by us.\nOn examining the external coverings of Hydra, we shall readily be enabled to convince ourselves of the formation of these organs. The most different stages of developement may here be seen, viz. developed prickles, either free or still enclosed by a cell membrane, from which the organ itself, and especially the fibre enclosed in its interior, recedes more and more, until it finally appears as a mere simple nucleus. In several Pianari\u00e6 the organs are contained, in an imperfect state, in considerable numbers in one common cell. The nuclei in the interior of the cells have therefore multiplied here, as in the seminal cells of the vertebrata.\nOrganization of the spermatozoa.. \u2014 At the period when the spermatozoa were still considered as individual animated creatures, it was natural that those qualities should be sought for, which distinguish animals gene-\n* According to the discovery of Frey and Leuc-kart (Wagner\u2019s Zootomie, ii. p. 61.), which subsequently, has also been made by H. Meckel (Muller\u2019s Archiv. 1846, S. 26.).\nf Vid. Henle (Allgemein. Anat. S. 193.) and Zwicky (Metamorphose der Thrombus).\nX R. Wagner in Weigmann\u2019s Archiv. 1835.\nrally ; and it was frequently asserted that the distinct traces of an internal organization had been found in them. Even Leuwenhoek the oldest observer of these structures, describes in the body of the spermatozoa of the ram and of the rabbit, indications which were subsequently interpreted by Ehrenberg j-and Valentin | to be intestines, stomachic vesicles, and even generative organs. Other histologers, for instance, Schwann and Henle, thought themselves justified in calling a dark spot, which shows itself occasionally in the body of the spermatozoon in men, but which is decidedly a mere accidental formation, as a suctorial cavity. But all these statements are now no longer believed in, as our present knowledge of the developement of these formations has entirely removed the idea of their parasitic nature. Indeed the subject requires no further refutation, as an unprejudiced observation will prove that the spermatozoa are every where void of a special organization, and consist of an uniform homogeneous substance, which exhibits, when examined by the microscope, a yellow amber-like glitter. The above mentioned investigators have by this time undoubtedly seen their error.\nMotions of the spermatozoa. \u2014 The opinion of an internal organization of the developed seminal elements was not a little supported by the various remarkable phenomena of motion, which were frequently perceived in them. In former times, when people had no idea of the existence and extent of the so-caUed automatic phenomena of motion, which take place without the intervention or influence of the nervous system ; when nothing was known of the'motion, very similar to a voluntary one, which exists even in plants; this movement was certainly calculated to place the independent animal nature of the spermatozoa almost beyond a doubt. But it is different now. We now know that motion is not an exclusive attribute of animals, and that an inference respecting the animal nature of the formations in question, however similar the motion observed in them may be to that of animal organizations, is a very unsafe and venturesome one. We know that certain elementary constituents, animal as well as vegetable, possess a power of movement, and that they even retain it for some time after haying been separated from the organisms to which they belonged. We only here need remind our readers of the so-called ciliated epithelia, the severed cells of which swim about in the fluid surrounding them, and which, when in this state, have not unfre-quently, and that even quite recently, been considered as independent animals $ ; how,\n* Opera, vol. iv. pp. 168. 284.\nt Infusoriensthierchen, S. 465.\nX Nov. Act. Acad. Leopold, vol. xix. p. 239.\n\u00a7 For instance, Nordmann, has described the severed ciliated cells from the sails of the larv\u00e6 of Nudibranchiata as parasitic Infusoria (Cos-mella hydrarhaoides). (Versuch einer Monographie der Tergipes Edwardsii. Petersburg^ S. 97.)","page":502},{"file":"p0503.txt","language":"en","ocr_en":"SEMEN.\t503\nfurther, the spores of the alg\u00e6 possess motion by the aid of a ciliated investment *, or of a single or manifold long whip-like fibre, until they eventually become fixed, and develop themselves into a new plant.f Such spores as these may be found described and illustrated in the well-known magnificent work of Ehrenberg, classified as Infusoria under the groups of Monadina, Volvocina, &c.\nUnder such circumstances we may consider ourselves perfectly justified in declaring every attempt to prove the parasitic nature of the spermatozoa, by the characteristic of their peculiar motions, as futile and inadmissible. Developement, structure, and composition are the decisive characteristics in this respect, and these prove the fructifying elements of the semen to be mere elementary constituents of the body in which they are formed. The motions of the spermatozoa are therefore in their essence identical with the above mentioned automatic motions of cilia, &c. But the knowledge of the movement of the spermatozoa will always be interesting and important ; because, of all these phenomena, it is undeniably most closely connected with the locomotive motions of animals.\n\"We must not, however, lose sight of the fact, that these motions are not possessed in equal perfection by all spermatozoa, but that in many cases they are scarcely visible, and hardly equal the motions of the cilia. Indeed there are many spermatozoa which are perfectly motionless, particularly all those forms which owe their immediate origin to a metamorphosis of the nucleus, or of the wall of the primary cells. Only those spermatozoa which have been produced by an endogenous and new developement are capable of independent motions, and even not every one of these. No such movements have as yet been perceived in the spermatozoa of the Malacostraca (Isopoda and Amphipoda). They appear motionless and rigid. The same holds good with regard to the body of the spermatozoa when it has a short, round, or pyriform shape. It never then participates in the motions, which are in such cases altogether effected by the thinner, whiplike, caudal extremity. It is different, however, with those spermatozoa which possess a cylindrical body. The body here participates in the motion ; at least very frequently, as, for instance, among the scaly amphibia, among the birds (excepting among the singing birds), &c. But the motions of the body are less rapid, energetic, and various than those of the tail. They are principally limited to a bow-shaped curvature, similar to the motion of the Vibriones, which, like the Monadina, belong to the vegetable kingdom, and may undergo a further developement into fibrous fungi.\n* Yid. Unger, Die Planze im Moment der Thier-wendung ; also Yon Siebold, Dissert, de Finibus inter Eegnum Animale et Vegetabile constituendis.\n\u2022j- Fresenius, Zur Controverse \u00fcber die Verwandlung von Infusorien in Algen.\nIn order to observe the movements of the spermatozoa properly, they ought to be investigated under different circumstances. On putting a drop of thick semen from the vas deferens under the microscope, a slow motion only can usually be observed in the accumulated masses of spermatozoa. They present an appearance as if they had some difficulty in disentangling themselves from the tough fluid by which they are surrounded. On adding blood serum to it to dilute the mass, the movement becomes more lively,either instantaneously or gradually. Separate spermatozoa writhe once or twice, turn round on their axis, lash with their tail, and creep about in all directions over the field. The motion gradually imparts itself to greater numbers. Here and there, simultaneously all the individuals of a group begin to move ; or particular parts of the mass commence the movement. The remainder perhaps exhibit no motion, and sometimes this quiescent state is permanent.\nIf the movement of the spermatozoa be rapid, it assumes, for the most part, an accurate rhythm like a pendulum. The filiform tail vibrates like a whip, and the small corpuscle or head follows the impulse.-Frequently a peculiar trembling, dancing, or jumping is exhibited by the latter when the rest of the spermatozoon remains fixed and un-* moved. A serpentine creeping in all directions is produced during a slow motion, and is caused by an undulating contraction of the caudal appendix. These undulating motions are perhaps the most frequent which the spermatozoa (and even the thread-like forms which possess no visible body) present to our view. They often move in one straight direction, without turning aside, and altogether in such a way and with such a regularity as to resemble the locomotive motions of many of the lower animals.\nThe same regularity is met with in the motions of the long and rigid spermatozoa with a spiral body among the singing birds, which very frequently turn rapidly round their axis, and thereby advance with a screw-like or boring movement. Pendulum-like lateral motions are but rare.\nVery peculiar and different are the motions of the spermatozoa in the Salamanders, which-usually lie wrapped up like a watch spring, flat on a level. For a time they remain quiet until suddenly, by fits and starts, a trembling motion takes place, by which they turn themselves round in a circle, pretty nearly on the same spot. Some few (as the Bombinator) stretch themselves out, and travel with a slow undulating motion over the field of the microscope. The most remarkable phenomenon, however, consists in a peculiar wavelike motion on the surface, and which is solely caused by the rapid succession of undulating motions. We have also perceived a perfectly similar undulating motion in the very long, coiled-up spermatozoon of Geo-philus, which is occasionally so powerful as k k 4","page":503},{"file":"p0504.txt","language":"en","ocr_en":"504\tSEMEN.\nto cause the whole fibre to be moved round in a circle.\nThe normal movements of the spermatozoa just described must be distinguished from various other remarkable and irregular phenomena of motion which are perceived on treating them with water, particularly in the long and hair-like spermatozoa of the Insects, Gasteropoda, Helmintha, and Cirripeda, and also sometimes, although in a slighter degree, in those of the Reptilia and Mammalia. Siebold* was the first who estimated these latter phenomena at their proper value, attributing to them their real cause, viz. the hygroscopic quality of the spermatozoa.\nThese phenomena take place only on the addition of fresh water, whilst sea water exercises but little influence on the spermatozoa, which ,may be accounted for by the difference in the saline constituents of these fluids. This fact, however, is of the greatest importance, in a physiological point of view, because the fecundation of the ova in many marine animals does not take place by copulation, but is accomplished through the transfer of the spermatozoa by means of the sea water, and the influence of this medium should not be such as to destroy the power of motion on the part of the spermatozoa. In cases where the fecundation takes place in the same manner in fresh water, for instance in the muscles, the spermatozoa are but slightly hygroscopic, so that their integrity remains undisturbed.\nThese abnormal phenomena of motion, caused by the influence of water, exhibit something similar to that which is seen in a rope turned by a wheel in a rope yard. The spermatozoa roll themselves out in larger or smaller windings, and form simple or compound coils of the most variable kinds. Frequently they turn back again after some time, .and re-assume their original shape ; they frequently also remain in the position they have at first assumed. In short, changes take place every moment. When the fibres lie in a straight position, a number of coils are suddenly produced; but they disappear equally as quickly, and it is only after some hours, when \u2022all the spermatozoa have rolled themselves into these coils, that the movements finally cease.\nIt is interesting that the normal undulating motions of the spermatozoa, where they lie together in regular masses without being able to change their position, very frequently coincide in a remarkable manner, appearing to be carried out, as it were, by one common will. But although this may appear strange at the first glance, it cannot surprise us when we consider that the same behaviour is observed in the ciliated cells. We here see the motions in the cilia of one epithelium regulated, as it were, by one common plan ; we observe how these coincide with the movements of the cilia of others, and thus unite into one regular motion of the whole. A\n* Muller\u2019s Archiv. 1836, S. 19.\npeculiarly beautiful sight is afforded by the aggregate motion of the spermatozoa in the semen of the earth worm, which resembles the undulating motion of a corn field. Among the insects we have also various opportunities of observing this kind of aggregate motion.\nA similar aggregate motion is frequently (especially among the Invertebrata) found in the separate bundles of spermatozoa, even when they are still surrounded by their cystlike enclosures. At first sight it creates an impression as if an undulating fluid were agitated in the interior of the cysts, whilst it is merely the winding motions of the spermatozoa, which follow each other in quick and regular succession, imparting the impulse to the whole mass.\nMotion, however, is entirely wanting when (as is especially the case among the insects) the spermatozoa are united into simple and uniform cords. A slight curving or trembling is only observed now and then, which is evidently the consequence of hygroscopic conditions.\nWe know as little of the cause of the movements of the spermatozoa as we do, in point of fact, of the remote cause of every motion. But that it depends on certaimrelations of structure and composition, is eyident from the circumstance, that it !is wanting in the undeveloped spermatozoa, only gradually taking place with progressive developement. A slight vibration or beating with the tail is first of all observed in them. The most lively, most vigorous, and most combined motion takes place, on the other hand, during the period of rutting, when the developement of the fructifying spermatic elements has reached its height.\nBut the motion of the spermatozoa is not even then unlimited. The death of the animal in whose spermatic organs they are contained, or their removal from it, only allows the motions of the spermatozoa to survive for a time, which, however, is of a different duration in different animals. It seems to be shortest in the birds, where the motion frequently is extinguished fifteen or twenty minutes after death ; at least it can but rarely be observed after some hours. In the mammalia their motion survives some time longer, especially if they remain enclosed in their natural organs.\nDeath, or removal, seems to have a different influence on the spermatozoa of the coldblooded animals ; among the fishes, for instance, they continue moving for days after having been expelled from the body. The mode of death of the animals has no influence at all upon the duration of the motion in the spermatozoa. It remains all the same whether the animals are decapitated, strangled, or poisoned.\nThe motion of the spermatozoa survives longest of all in the interior of the female generative organs. The insects (in whom, as in Gasteropoda and some other animals, particular pockets or capsular organs are developed during the period of procreation) furnish","page":504},{"file":"p0505.txt","language":"en","ocr_en":"SEMEN.\t505\nthe most striking proof of this. The spermatozoa, when enclosed in these, frequently retain their full vitality for months. Among the mammalia, likewise, the motions of the spermatozoa remain unimpaired in the vagina, or in the uterus, for some days after copulation.\nThe mucous coat which covers these organs has no prejudicial effect on the motion and vigour of the spermatozoa*, and equally as little so the addition of other animal fluids, as the secretion of the prostate, the serum, milk, &c. Common saliva, and even bile or pus, does not exercise any impeding influence upon the motions of the spermatozoa.\nThe addition of urine, especially when having an acid reaction, seems to have a rather more injurious influence upon them, for their motion ceases soon afterwards, although for same hours slight traces of it may still be perceived.\nWe have already treated of the influence of common water upon the spermatozoa. Diluted saline solutions or sugar and water, on the other hand, either do not produce these injurious effects at all, or, at least, only in a very slight degree. The chemical agents are the only ones which have a positively injurious effect on the spermatozoa, changing and destroying their structure and composition ; as for instance alcohol, acids, metallic salts, &c. Diluted aqueous solutions of narcotic vegetable substances, of strychnia, morphia, &c., have the same effect as common water.\nThe electric spark destroys the motion of the spermatozoa instantaneously, unquestionably because it changes their structure. Galvanism, on the other hand, remarkable to say, has no effect upon them, as Pr\u00e9vost states. A high or low temperature likewise causes the motions to cease, or at least to slacken, although the motions of the spermatozoa of frogs and fishes continue when the surrounding medium sinks below zero. The same has been observed in the spermatozoa of Limn\u00e6us and Planorbis on treating them with hot water of 70\u00b0\u201480\u00b0 (Centigrade).\nChemical composition of the semen. \u2014 The semen in most animals is a tough, thick, white, yellow, or darkish grey fluid, heavier than water, falling to the bottom when shaken with it. Its taste is sharp and astringent. The peculiar smell, which is usually attributed to it, is comparable with the smell of bone filings, and has its origin, perhaps, in the secretions mixed with it. Pure semen in man and animals does not seem to give forth any decidedly striking smell.\nThe chemical .analyses of semen are dated from a period when our knowledge of organic combinations was still very imperfect, and far from having attained that elevation, by which it has become equally important to physiology as the study of morphology. The works of\n* For numerous researches on the influence of reagents on the movements of the spermatozoa, viel. Donne\u2019s Nouvelles Experiences sur les Animalcules Spermat., Paris, 1837 ; as well as Kr\u00e6-mer, p. 17. In some cases, however, our own researches have furnished a different result.\nFour crop, Vauquelin, Jordan, John, and Las-saigne, are still the sources from which we derive our knowledge of the chemical nature of the semen.\nVauquelin, whose analysis is the most elaborate, found in the human semen ninety parts of water, one part of soda, three of phosphate of lime and chloride of calcium, and six parts of a peculiar substance (spermatine). These statements were afterwards confirmed by John and Lassaigne. Spermatine,howeyer, the more intimate knowledge of which would have possessed the principal interest, was no further investigated than it had been previously by Vauquelin.\nUnder such circumstances it appeared desirable to undertake a new chemical analysis of the semen, especially as the former researches had embraced the wdiole mass, without paying regard to the morphological constituents, or to the admixture of the prostatic secretion. To remove this defect, a series of researches has been instituted by Dr. Frericks at our request, in the new chemical laboratory of the physiological institute of Gottingen, respecting which the following has been communicated to us for publication.\nThe most careful of these analyses was made on the semen of the carp, it being a fish which is perhaps best calculated for an investigation of this nature. The testicles were cut into pieces, and crushed, in order to press out the semen. Thus obtained, it presented a whitish, glutinous, or viscid mass, from which the membranous fragments were carefully removed. The residue of pure semen consisted of the spermatozoa, suspended in a fluid, and a few epithelial cells. It was perfectly neutral.\nThe corpuscular parts of the mass of semen were now separated from the fluid by filtration, and both were separately examined.\nThe fluid was colourless and clear, of a neutral reaction. The fluid at first filtered exhibited no coagulation when boiled, nor was it precipitated by nitric acid. Albumen, therefore, was not present. The liquid which subsequently passed through, however, on washing the mass, precipitated a small quantity of albumen on being subjected to a boiling heat, as also on being treated with nitric acid. Acetic acid, tannic acid, alum, and acetate of lead likewise precipitated albumen.\nOn being evaporated, the fluid left a yellowish, gum-like mass with a strong fishy smell. It re-dissolved partially in water, but w'as precipitated from it by tincture of galls. The insoluble residue was easily dissolved by diluted solution of potash, and precipitated by acetic acid, without being again dissolved by an excess of it.\nA part of the evaporated semen was burnt : there remained an ash, consisting of chloride of sodium, as also of slight quantities of phosphates and sulphates of the alkalies.\nThe spermatic fluid therefore resembles a thin solution of mucus.\nThe spermatozoa which were left after","page":505},{"file":"p0506.txt","language":"en","ocr_en":"506\tSEMEN.\nfiltration were carefully washed with water : they were thus quite pure, excepting the admixture of some few epithelial cells. The subject used in the investigation had attained full generative maturity,and was almost devoid of vesicles of developement.\nThe spermatozoa were dissolved by cold solution of potash ; a certain cloudiness which remained was due to epithelia that were slowly dissolved. The alkaline solution exhibited a copious precipitate on the addition of acetic acid ; but the precipitate was insoluble in the excess of the acid, even by digestion. It was filtered off, and the acidulated fluid treated with potash, iron, and cyanic acid, but no cloudiness was produced. The substance of the spermatozoa coincides, therefore, with the \u201cbinoxyde of protein\u201d of Mulder; it contains no albumen or fibrin.\nA part of the spermatozoa were dried in a water bath, pulverised, and treated with ether. During this process they yielded a not inconsiderable quantity of fat (4\u201905 per cent.) of a yellowish colour and butter-like consistence. The spermatozoa, liberated from this fat, left, on being burnt, a black coal, which could not be made white by burning, and had an acid reaction, which was due to free phosphoric acid. The total quantity of fixed constituents, in which, besides the phosphoric acid, lime was recognised, amounted to 5'2l per cent.\nAnother portion of the expressed semen was treated with a concentrated solution of nitre. It thereby became considerably tougher, more viscid, and filtered with difficulty. On adding water, a milk-like cloudiness was produced in the filtered portion ; it was, however, precipitated in the same manner as the simple watery extract by the infusion of galls. Nitric acid caused a slight precipitate of albumen.\nA second series of experiments was instituted on the semen from the testicles of a cock, in which, however, the spermatozoa were only scantily developed. The contents of the seminal tubes principally consisted of cells of developement, which could only be separated with difficulty from the tissues of the testicles.\nThe filtered solution abounded in albumen, but contained, on the other hand, only a slight quantity of the matter (mucus), which was pr\u00e9cipitable by acetic acid, and insoluble in excess of it.\nThe residue on the filter (cells of developement and spermatozoa) was dissolved in solution of potash. The solution yielded a white precipitate with acetic acid, which principally dissolved in excess of the acid (albuminous substance), whilst only a slight quantity remained undissolved (binoxyde of protein).\nAn old rabbit, when in the period of rutting, was subjected to a third series of experiments. The moderately turgid testicle was cut into pieces, and the milky semen expressed. It consisted of spermatozoa and numerous epithelial cells. The reaction in the testicles was\nneutral, in the epididymis it was slightly alkaline. It could only be filtered imperfectly. The filtered solution was cloudy, and contained many spermatozoa. The presence of a slight quantity of albumen could be perceived on the application of boiling heat.\nThe residue of spermatozoa left on the filter, and which were only imperfectly separated from the fluid, dissolved with tolerable ease in solution of potash, and were precipitated by acetic acid. A very slight quantity only dissolved in an excess of this acid. Only a slight cloudiness was produced in the acetic solution by ferro-cyomide of potassium.\nThese different experiments yield the following results : \u2014\n1.\tThe pure semen presents the appearance of a milky fluid, of a mucous consistence, and neutral reaction. A slight alkaline reaction was perceived only once.\n2.\tThe developed spermatozoa consist of binoxyde of protein, the same substance which Mulder has proved to be the principal constituent of the epithelia, as well as of the horny tissues in general.*\n3.\tThe spermatozoa contain about 4 per cent, of a butter-like fat, as well as phosphorus in an unoxydized state, and about 5 per cent, of phosphate of lime.\n4.\tThe fluid part is a thin solution of mucus, which, in addition to the animal matter, contains chloride of sodium and small quantities of phosphate and sulphate of the alkalies.\n5.\tThe imperfectly developed spermatozoa are composed of an albuminous substance, the quantity of which diminishes in proportion to the progress of the morphological developement.\n6.\tThe perfectly developed semen contains no longer any albuminous compound.\n7.\tThe semen in fishes, birds, and mammalia possesses, essentially, the same chemical composition.\nSuch are the statements of Dr. Frerichs. The most important inference derivable from them appears to us to be the fact, that the spermatozoa, in their chemical composition, belong to the same category as the epithelial cells of the animal body. This fact removes every doubt respecting the nature of these formations, \u2014 every idea of their being independent animals. The spermatozoa are therefore (as proved both by chemical analysis and by microscopical investigation) mere elementary constituents of the male animal body, which, like their equivalents in the female animal, the ova or contents of the ovaries, are distinguished from other histological elements by their having a different physiological purpose ; they have less influence on the individual in which they are produced, but are intended, when separated from that individual, to give rise to the formation of a new one.j-\n* Versuch einer Allgem. Physiolog. Chemie. \u00a7 532. 560.\nf In spite of this functional difference we cannot help regarding spermatozoa and ova as constituents of the animal organization. Eeichert, who declares them to be organizations of quite a peculiar kind,","page":506},{"file":"p0507.txt","language":"en","ocr_en":"507\nSEMEN.\nIt is probably no false inference on our part, when we express the opinion that the developed seminal elements present every where, and not merely in mammalia, birds, and fishes, the same composition. Indeed, we do not see any reason for assuming that this differs even in cases where the proper fluid is wanting, and where it is only the spermatozoa which constitute the seminal mass.\nPhysiological office of the semen. \u2014 Although these results of chemical analysis appear very important for the knowledge of the nature and quality of the semen, yet they afford but little assistance to an investigation respecting its modus operandi in the process of fecundation. Indeed, it would almost seem that an answer to such an inquiry is farther oft\u2019 than ever, inasmuch as we now know that a peculiar substance of a specific quality exists, which w7e may indeed consider as the bearer of the fructifying principle,\u2014but that an effective spermatine does not exist. The truth is, \u201c the how\u201d of the fecundation is as far from our knowledge today as it was thousands of years ago ; this process is still enveloped in what we feel inclined to consider \u201c its sacred mystery.\u201d It would be different if we could prove that the spermatozoa really yielded the material foundation for the body of the embryo ; that they penetrated into the ovum, and were developed into the animal (which was the assumption of Leuwenhoek, Andry, Gautier), or else, that they become metamorphosed into the central parts of the nervous system.\nHowever, we are now convinced that all these assumptions are without any foundation. The import- of the spermatozoa must be a very different one. But this is the very point of which we know nothing with any certainty.\nLeaving these views, which require no special refutation, to oblivion, the following two opinions on the nature of fecundation have taken a tolerable position in our physiology :\n\u25a0\u2014 One of them consists in the opinion that the fructifying principle is lodged in the liquor seminis ; the other, that it is centred in the spermatozoa. Both, however, agree in this, that an actual material meeting, an immediate contact of semen and ova, is indispensable to effect fecundation. The doctrine of an Aura seminalis has long since, and most justly, been cast aside.\nIt was natural that the former of these two opinions (viz. that which sought the essentials of fecundation in the fluid and its mode of action) should have found its advocates at a period when the existence of the spermatozoa was hardly known, or when, at all events, they were supposed to be mere parasitic animal forms.\nIndeed, this assumption is at first sight sup-\nwhich, in a certain degree, form a medium between animals and elementary parts of animals, seems entirely to forget that it is only the morphological condition, which can characterise a constituent of the body as such. The physiological comportment by itself ought not here to be taken into consideration at all.\nported by arguments of a seductive nature. The liquor seminis, it was thought, comes into contact with the membranes of the ovum, and transudes them. It mixes itself with parts of the yolk, and enters with them into many chemical combinations, which fit them for a change in their capacity for organization, for the formation of cells, and for thedevelopement of the embryo. This opinion did not, indeed, suffer at first from the recognition of the normal nature of the spermatozoa. It was indeed possible, as Burdach thought, to find in this very circumstance a proof of the great organizability of the semen, of the ready mode of dispersing it, which such an operation upon the ovum would \u00e0 priori require.\nEven up to the present day this hypothesis of the influence of the liquor seminis has not met with any direct refutation, although, as we shall see presently, it appears to us now, for many reasons, less admissible than it did to one of us formerly.* The presence of certain elementary structures in the seminal fluid cannot yet be connected with the part which they are intended to perform. It was indeed possible that the remarkable qualities of these structures had reference to the seminal fluid alone ; that they, as it were, formed isolated, free, ciliated epithelia, and that they were intended, by means of their movement, to bring the liquor seminis into contact with the ovum ; or, as Valentin supposed, that the state of mixture of the semen, so readily disturbed, was preserved in its integrity through their motions. The circumstance of meeting now and then with motionless spermatozoa is not in itself sufficient to refute this conjecture. For it might be said that in these cases such a provision might not be necessary, or that the object sought might be gained in another way, and that the spermatozoa merely existed as morphological equivalents of the moveable seminal fibres, without a similar physiological importance.\nThe following fact, however, appears to us of more real importance, viz. that a liquor seminis is positively not at all traceable in many, and especially not in many of the lower, animals, in worms, insects, &c. ; but that, on the contrary, the whole mass of the semen is formed by the spermatozoa alone. Another reason against the former assumption is this, that an action of the liquor seminis on the ova would be impossible in many cases,\u2014 where, for instance, the fecundation takes place in the water, and without any real act of copulation, the semen being ejected from the male animals, and then left to chance whether it comes in contact with the ova or not.\nSuch facts speak too powerfully in favour of a specific purport of the spermatozoa in the act of impregnation to allow us to venture to say a word in support of the older assumption. In addition to this, it must be granted that the spermatozoa in the male individuals are, in a morphological point\n* R. Wagner, Physiologie, S. 88.","page":507},{"file":"p0508.txt","language":"en","ocr_en":"008\nSENSATION.\nof view, the representatives of the female generative products \u2014 the ova ; and that, as explained in the commencement of our article, we are enabled to pronounce the presence of a particularly large quantity of liquor seminis as a fact of subordinate significance in a histological point of view.\nUnder these circumstances we do not hesitate any longer to coincide with K'\u00f4lliker and Bischoff* (the latter changed his opinion only recently) \u201c that it is the spermatozoa which, by their contact, fructify the ovum.\u201d How this is done remains as much an enigma as the real essence, the remote cause, of every thing else that is done. We are certainly able to watch growing life in its first commencement, to fathom the laws of the successive phases of its developement ; but the internal relation of all these processes is hidden from our perception.\nIt is possible, and, indeed, even probable, that the material constitution of the spermatozoa is somehow concerned in fecundation. Whether, however, as Bischoff supposes, the act of impregnation merely takes place according to the law's of the so-termed catalytic power, that a certain internal motion is transferred from the spermatozoa to the molecules of the ova, which till then were in a dormant state, we do not venture to decide. At all events, the circumstance, that it is not the spermatozoa of every animal which are capable without any distinction of fructifying every egg, is sufficient in itself to prove that we have not here to deal with such very simple relations. It is an established fact, that only animals of the same species enter voluntarily into sexual connexion, and produce prolific young ones. The importance of this law, for the preservation of once created definite forms of life, is evident.\nExceptions to this law are but rarely found, and generally are due to the interference of man.\u2014 Animals of a different species scarcely ever enter into sexual connexion in their natural state ; and, indeed, this act, when it does take place under such circumstances, remains generally without any consequences. Fecundation only takes place when the respective individuals approximate towards each other in point of genus, and even then the hybrids produced are generally unfruitful. A fructifying act of procreation is known in them only in very rare cases, and that usually only when it takes place with one of the original stock, not among themselves.\nThis infertility or barrenness of the hybrids, coincides in a very interesting manner with an imperfect developement of the spermatozoa, a relation which we might certainly at once infer from the functional significance of these formations. In many cases there does not even seem to be any production of spermatozoa ; a fact proved by the older statements of Bonnet and Gleichen, as well as by the more recent researches of Pr\u00e9vost and\nDumas *, as well as of Hausmann f, with regard to the mule. One of us J found the same in the hybrids of goldfinches and canary-birds. In others, real spermatozoa develop themselves ; but they remain smaller than in the stock species (^///\u2014and without the characteristic cork-screw spirals. The thicker end is generally oblong, and frequently curved at the point, or of an irregular club form. In addition to this, the spermatozoa of the hybrids do not group together in bundles, owing perhaps to their being usually only small in number, even in the interior of the separate cysts. The microscopical examination of the semen in hybrids, the capacity of propagation of which has been confirmed, would be of importance. It is very probable that the spermatozoa in these cases have a regular developement, and their usual form.\nBibliogkaphy. \u2014 A. Leuwenhoek, Anatomia seu Interiora Rerum, Lugd. Batav. 1687 ; Arcana Naturae, Delphis, 1695 ; Epistol\u00e6 Physiologic\u00e6, Delphis, 1719; Sur les Animalcules de la Semence des Animaux, Philos. Trans; 1672. Lederm\u00fcller, Physikalische Beobachtungen der Samenthierchen, Nuremberg, 1756. Spallanzani, Nouvelles Recherches sur les D\u00e9couv. Microscop., Londres, 1769. Gleichen, Abhandlung \u00fcber die Samen, und Infu-sionsthierchen, Nuremberg, 1788. Pr\u00e9vost and Dumas, Annal, des Sc. Nat. tom. i. ii. Czermak, Beitr\u00e4ge zur Lehre von den Spermatozoen, Vienna, 1833. Treviranus, in Tiedemann\u2019s Zeitschrift, vol. ii. Von Siebold, in M\u00fcller, Archiv. 1836, S. 232. ; 1837, S. 381. R Wagner, Fragmente zur Physiologie der Zeugung ; Beitr\u00e4ge zur Geschichte der Zeugung und Entwickelung ; in den Abhandl. der K\u00f6nigl. Baeierisch Acad., Munich, 1837. K\u00f6lliker, Beitr\u00e4ge zur Kenntnisse der Geschlechtsverhaltnisse und Samenfl\u00fcssigkeit wirbellosen Thiere, Berlin, 1841 ; Die Bildung der Samenf\u00e4den in Bl\u00e4schen, Nurembg. 1846.\n(JRud. Wagner and Rud. Leuckart.)\nSENSATION. \u2014 (Fr. Sensation; Germ. Empfindung.) \u2014 The improved state of our knowledge of the physiology of the nervous system makes it imperative that physiologists should adopt and adhere to a precise definition of the term which forms the heading of this article.\nPerhaps the simplest definition of sensation which can be given is the following ; namely the perception by the mind of a change wrought in the body. According to this definition, then, sensation involves, first, a bodily change, from some cause, whether inherent or external ; and, secondly, a mental change, whereby the perception of the bodily change is accomplished. \u00c0 hot substance is applied to the skin sufficient to burn ; a visible change is produced on the part to which the application has been made, shown by the increased redness of the cutaneous surface, and the nerves of the part are so irritated that pain must be felt if the perceiving power of\n* Annal, des Sciences Nat. i. p. 182.\nf Ueber der Mangel der Samenthierchen bei Haus-thierchen ; Hannover, 1844.\n1 R. Wagner\u2019s Physiology, \u00a7 20. Translation by Willis, \u00a7 12.\n* M\u00fcller\u2019s Archiv. 1847, S. 436.","page":508},{"file":"p0509.txt","language":"en","ocr_en":"SENSATION.\t\u00d609\nthe mind be unimpaired. But unless the mind is conscious of the irritation excited we cannot say that a sensation has taken place. The person on whom the injury is inflicted may be comatose, or in a profound sleep, or under the influence of intoxicating or anaesthetic agents, and consequently his perceptive powers are in abeyance. Nevertheless, the same physical changes take place, whatever be the state of the mind, and all the physical phenomena, which may flow from or succeed to those which are capable of exciting sensation, may ensue upon them, and yet true sensation will not take place, unless the mind perceives and takes cognisance of the physical change induced.\nIt must then be regarded as a cardinal point in reference to the acceptation of the term Sensation in Physiology, that an action of the mind is necessarily involved, that act being of the nature of a recognition or perception of the physical changes associated with the sensation.\nThe true organ of sensation is the organ of the mind \u2014 the brain, and especially that part of the brain which constitutes the centre of sensation, and which extends into the spinal cord, forming the posterior horn of its grey matter. When an impression is made upon a nerve or nerves which communicate directly or indirectly with any part of this centre, a sensation is excited, provided the intracranial portion of it be in a normal state, and provided also the connection between the cranial and spinal portions be complete and uninterrupted.\nSensations depend, as to their nature, on that of the excitant, and nerves are adapted to receive impressions from various agents, ponderable or imponderable. The mechanical qualities of bodies, heat, cold, electricity, light, sound, &f., are capable of exciting their appropriate sensations, which the mind soon learns to appreciate and distinguish. Sensations thus distinguished receive the appellation of pleasurable or of painful, according as they are agreeable or the reverse. These sensations are infinitely varied in kind and in degree. It is impossible, \u00e0 priori, to determine how a pleasurable or a painful sensation may be excited. Nor will the experience of one person be always a guide for another, inasmuch as a sensation which may be agreeable to one, may be painful or disagreeable to another.\nPhysiologists distinguish sensation as common and special : the former being that which is excited by ordinary mechanical or chemical stimuli ; the latter is excited by special stimuli, and is exemplified in the special senses of vision, hearing, smell, taste, and touch. The nerve of vision does not, when irritated, communicate simply a feeling of pain or of pleasure ; its chief effect is to excite the sensation of a flash of light. When the electric stream passes through the retina, a sensation is caused similar to .that which the sudden presentation of a luminous object would produce. In like manner the mechanical or electrical stimulation of the other nerves of pure sense will create, not pain, but a feeling\nclosely allied to that which would be excited by the application of the stimulus proper to each. This is remarkably illustrated by the effects of mechanical or electrical stimulation of the nerve of hearing and of the nerve of taste. Mechanical impulses against the tympanum occasion the sense of a dull sound, and the electric current developes a musical note. Galvanic excitation of the gustatory papillae of the tongue causes a peculiar sour taste, and, as Dr. Baly has pointed out, the mechanical stimulation of them by a sharp tap with the fingers, occasions a taste sometimes acid, sometimes saline.\nThe nerves which minister to specia sensation, differ from the nerves of common sensation in no essential point of their anatomy, except in their mode of organisation at the periphery of the body. Each of them has, probably, likewise some peculiarity of connection with the brain : this is obvious as regards the olfactory and the optic nerves ; less so as regards the nerves of taste, touch, and hearing. . The physiological peculiarity of these nerves is then, in all probability, due to their central and peripheral organisation ; and especially, perhaps, to the latter, which, doubtless, renders them peculiarly susceptible of the influence of those delicate physical agencies to which each of them is exposed.\nThe nerves and organs of special sensation, especially those of touch, are so comprehensive in their objects, that it would almost seem that little was left for the so-called nerves of common sensation.\nThese latter nerves, nevertheless, serve many important objects ; they doubtless excite in the mind many feelings, agreeable or disagreeable, of pain or of pleasure, or even feelings neutral as regards pain and pleasure, which could not be developed through the nerves of special sense. The consciousness of the integrity of our limbs and of the general framework of our bodies, is secured, in a great measure, through the instrumentality of these nerves. Injuries to various parts\u2014disturbances in their nutrition, as inflammations, ulcerations, &c. \u2014 are made known to the mind by the painful sensation excited through these nerves. The sensibility of organs and textures \u2014 i. e. the degree to which affections of these parts are capable of inducing corresponding affections of the mind \u2014 depends upon the number of these nerves which are distributed to them \u2014 the degree of sensibility being in proportion to the number of the nerves. Hence these nerves of common sensation exercise a conservative influence over the several textures and organs to which they are distributed, and serve to afford warning of the approach or of the existence of danger.\nWhat some have called the muscular sense, i. e. the knowledge which we have of the state of our muscles, is generally attributed to these same nerves. As the sensibility of the muscles is doubtless due to these nerves, we may reasonably impute to them the faculty of informing the mind of the state and degree of contraction or relaxation of the muscles, and thus of contributing to that power of adjust-","page":509},{"file":"p0510.txt","language":"en","ocr_en":"510\tSENSIBILITY.\nment which is necessary to give precision to our muscular efforts. This sense comes greatly in aid of that of touch, and of those powers which we derive from the sense of touch,\nIt admits of question whether this sense really requires the presence of true nerves of sensation in the muscles, and whether it may not be due to the reaction of the muscular force upon the proper muscular or motor nerves, through which, by reflection at the centre, the centre of sensation becomes affected. (See Nervous System, Physiology of.)\nAll nerves of sensation are excitors of motion under certain circumstances, but especially when they are organised at their peripheral distribution in a peculiar manner.\nObjective and subjective sensations. \u2014 In the ordinary mode of exciting sensations the presence of an object is necessary. This object creates an impression on the peripheral parts of the sensitive nerves ; and the change caused by this impression, being duly propagated to the centre of sensation, is perceived by the mind. Thus is produced what some metaphysicians call an objective sensation.\nSuch sensations are durable or transient, according to the force of the primary impression. The mind may continue conscious of the sensation long after the exciting object shall have been withdrawn ; or the sensation having ceased, the mind may recall it, with more or less exactness, without the renewal of the original stimulus. This is one form of subjective sensation, in which a mental act can develope a sensation independently of any present object, but resembling a previously experienced objective sensation. Other forms of subjective sensations are caused by physical changes in nerves themselves, or in those parts of the centres in which they are implanted. These changes are caused by alterations in the quantity, but more frequently in the quality, of the blood, the deficiency in some of its staminal principles, or the presence of some abnormal element in it, or by modifications in the nutrient actions of the nerves or nervous centres. Subjective sensations of this kind are those most commonly met with. As examples of them we may refer to the motes or flashes of light occasioned by disturbed conditions of the retina, mechanically or otherwise ; or of the optic nerve; or of those parts of the encephalon in which the optic nerve is implanted ; tinnitus aurium, or singing in the ears, resulting from some analogous affections of the auditory nerve, or of the parts of the brain with which it is connected ; pains, or feelings of tingling or creeping in the limbs (formication).\nReflex sensations. \u2014 The physical change developed in the production of an objective sensation at one part may give rise to what may be compared to a subjective sensation in another and a remote part of the body. The irritation of a calculus in the bladder will give rise to pain at the end of the penis, or to pains in the thighs. The ob-\nject by which the irritation of the bladder is excited cannot exercise any direct influence on the nerves of the penis or of the thigh ; through the nerves of the bladder it excites that portion of the cord in which both the vesical nerves and the nerves of the penis and of the thigh are implanted, and thus the latter nerves are stimulated at their central extremities through the influence of the peripheral stimulation ; in other words, the physical changes excited in the first are reflected into the second.\nSometimes distant and apparently wholly unconnected parts may be affected in this way. Thus irritation of the ovary will cause pain under the right or left mamma ; stimulation of the nipple, whether in male or female, gives rise to peculiar sensations referred to the genital organs ; ice suddenly introduced into the stomach will cause intense pain in either supra-orbital nerve ; acid in the stomach is apt to cause a similar pain, which may be very quickly relieved by the neutralisation of the acid. Phenomena of this kind imply some closeness of connection between the nerves of the sympathising parts in the centre, probably by means of commissural fibres connecting the respective points of implantation of the nerves with each other.\nFor further remarks on the subject of this article see Nervous System, Physiology of ; and the articles on the Senses, \u2014 Hearing, Smell, Taste, Touch, Vision.\n(R. B. Todd.)\nSENSIBILITY.\u2014 (Fr. Sensibilit\u00e9; Germ. Empfindlichkeit). \u2014- This term, like Sensation, should be limited to signify the power which any organ or tissue of the body has, of causing changes inherent or excited in it to be perceived and recognised by the mind. The greater this power is in any tissue or organ, the more sensitive it is, \u2014 the greater the sensibility of the organ or tissue ; the less this power is, the less the sensibility of the organ, &c.\nSensibility, like Sensation, involves the power of affecting the mind through the body; but as the mind, of its own mere motion, may excite the centre of sensation, so, by directing the attention specially to some particular tissue or organ, it may create a sensation which, will be referred tothat part,and which, by frequent repetition, may assume the nature of pain.' No doubt many instances of hysterical pain are greatly aggravated by the mind being constantly directed to, and dwelling upon, the painful part.\nThe term Sensibility is sometimes confounded with Irritability, especially by Psychological writers. Haller has, with great precision, laid down the distinction between these two properties of tissues in the following words : \u2014\n\u201c Irritabilem partem corporis humani dico, qu\u00e6 ab externo aliquo contactu brevior fit ; valde irritabilem, quae a levi contactu, parurn qu\u00e6 a valente demum causa in brevitatem cietur. Sentientem partem corporis humani","page":510},{"file":"p0511.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t511\nappello cujus contractus anim\u00e6 representatur ; et in animalibus brutis, de quorum anima non perinde liquet, eas partes sentientes dico, quibus irritatis animal doloris et incommodi signa ostendit ; insensilem contra partem qu\u00e6 usta, scissa, puncta, ad destructionem usque c\u00e6sa, nullum doloris signum, convulsionem nullam, nullam in totius corporis situ muta-tionem excit\u00e2t.\u201d *\nThe sensibility of any part must be judged of by the readiness with which changes in it are perceived by the mind. In general, highly sentient parts, when stimulated, are capable of exciting movements in the muscles of neighbouring parts ; thus, stimulation of the sole of the foot excites motions in the whole lower extremity ; the stimulation of any other part of the leg, whilst it might excite movements, would not produce them to the same extent. The difference is due to the greater ; sensibility of the sole of the foot than of any other part of the integument of the lower extremity, and also to the peculiar connection of its sentient nerves with the papillary texture of the skin.\nThe anatomical condition necessary for the developement of the greater or less sensibility in an organ or tissue, is the distribution in it of a greater or less number of sensitive nerves. Thus the anatomist can determine the degree to which this property is enjoyed by any tissue or organ by the amount of nervous supply which his research discloses ; and physiological experiments and surgical operations furnish us with abundant evidence in confirmation of the, as it were, \u00e0 priori suggestions of the anatomist.\nThe sensibility of tissues is modified by disturbances of their nutrition, and thence inflammatory affections tend to increased sensibility, and will even make parts sensitive which before were but slightly so. Thus the periosteum, which in health is but slightly sensitive, becomes, under the influence of inflammation, exquisitely sensible.\nIt is necessary to add that the word sensibility is also used, as applied to nerves, to signify their power of evolving the nervous force. Excitability is a better word for this purpose, and ought to be generally used, to ensure a greater exactness in the application of physiological terms than has hitherto prevailed.\n(R. B. Todd.)\nSEROUS and SYNOVIAL MEMBRANES.\u2014{Membranes s\u00e9reuses, Fr.; Ser\u00f6se Haute, Ser\u00f6se Ueberziige, Wasserhaiite, Germ. Membranes synoviales, Fr. ; Synovial-Kapseln, Synovial Haute,Germ.) \u2014The names by which these structures are designated seem to have been originally derived from the appearances presented by fluids which are frequently found after death in the so-called cavities formed by their continuous interior surface.\nThus, for instance, rejecting those cases\n* JHaller, De Partibus corp humani sentientibus et irritabilibus. \u2014 Op. Minora, t. i. p. 407.\nwhere marked symptoms of disease of these tissues precede death, the structures first named, where they offer any contents at all, present a fluid the colour and composition of which greatly approximate to that of the serum of the blood ; and thence the fluid so found names the tissues yielding it as the \u201c serous \u201d membranes : while the interior of the joints constantly affords a small quantity of a fluid, the viscid consistence of which, resembling that of the white of an egg, gives rise to the application of the name \u201c synovial \u201d membrane {aw wov) to the tissue which immediately lines the articulation, and is presumed to yield it.\nBut neither do these circumstances, nor that of their membranous form, by which the terms at the head of this article are completed, sufficiently express their most important characteristics. A serous membrane essentially consists of an endogenous cell-growth, covering a thin expansion of areolar tissue. The compound structure which results from this arrangement of these two tissues is thrown around the more moveable organs of the body, and also lines the cavities which they fill. By thus affording to these two opposed surfaces uniformity of texture and smoothness of surface, it greatly diminishes their mutual friction ; or, in other words, facilitates their movements upon each other.\nIt will, I think, be advantageous to defer for the present all consideration of the possible or probable function of these membranes, as implying by that word an immediate organic operancy in virtue of their intimate structure; and to fix our attention chiefly on their mechanical use in reference to motion.\nIn the living man, there are many processes which necessitate changes in the relations to space of the different parts of the body. The actions of locomotion, digestion, circulation, and respiration, for instance, all imply some degree of movement in the organs which are their immediate agents, often in the more important parts to which they immediately minister ; and, in many cases the protection of delicate organs appears to be partly accomplished by an increase of their mobility upon neighbouring structures. The necessity of movement thus comes to be more or less participated in by almost all the tissues, organs, and segments of the body ; and assuming, what is above stated, that it is the most obvious want for which serous membranes are destined to provide, we might naturally imagine, either that these structures would pervade as universally as this requirement, or that those of similar import which should be substituted for them would sufficiently approximate in their nature and composition to be referrible to the same class of tissues ; a class, in which the degrees of resemblance afforded by the different members should somewhat accord with the varying mechanical requirements of those different parts of the body, to the movements of which they were subservient.\nAn appeal to facts abundantly confirms","page":511},{"file":"p0512.txt","language":"en","ocr_en":"512\nSEROUS AND SYNOVIAL MEMBRANES.\nsuch an inference. Observation shows that in the human body a variety of structures exist, which are united by the characteristics not only of considerable analogy of office, but also of similarity of structure, almost complete identity of chemical composition, and intimacy of pathological relations.\nAdopting the possession of these common properties as a natural and safe basis of classification, we form a group in which are included all those tissues which serve to limit, define, or facilitate movement. The class of structures thus constituted was formerly termed \u201c the Cellular System ; \u201d but the eel-lularity which the name connotes, as it was never supposed to be predicable of all its members, so it is now known to be erroneously used of that part of them to which it was originally applied ; and they have therefore been preferably arranged under the head of \u201c Passive Organs of Locomotion.\u201d And if any should consider this term open to the lesser objection of specifying a general, but not essential fact, that of \u201c Passive Organs of Movement \u201d might be again substituted.\nOn this view we may regard serous membranes as forming one of a group of tissues. A further analysis of this group shows it to be composed of several members, separated from each other by differences, in which we may recognise a progressive, though somewhat interrupted, series of gradations. These differences we shall now proceed rapidly to trace.\nTwo important microscopical elements pervade all these structures, and will therefore demand some attention. These are the white and yellow fibrous tissues.\nThe white fibrous tissue (fig. 395. a) consists of bands or bundles of a very variable width, which, unless artificially stretched, take a sinuous or wavy course ; and, at distant intervals, include cell-nuclei in their substance. They are marked with striae, which take the direction of their length, and, by their mutual proximity, give a fibrous or fibrillated ap-\nFig. 395.\na, White fibrous tissue ; b, Yellow fibrous tissue. After Todd and Bowman. Magnified 320 diameer si)\npearance to the whole mass. But these markings are not exactly parallel to the borders of the band ; and since the tissue, though easily divided longitudinally to almost any degree of minuteness, cannot be split up into uniform and definite fibrils of a diameter corresponding with the transverse width which intervenes between one of these striae and another; and since it is also swelled up into one shapeless and semitransparent mass by the action of acetic acid ; it seems highly probable that they are limited to the surface of the bundle, or its immediate neighbourhood. At any rate, they do not sufficiently divide the mass to give it a filamentous constitution, or to render it \u201c fibrous \u201d in the true sense of the word.\nThe yellow fibrous tissue (fig. 395. b) is contrasted with the preceding form, not only by its colour, but equally by its minute structure and properties. It consists of separate fibres, the size of which varies considerably in different parts, and, in a lesser degree, in any one specimen. They are exceedingly disposed to curl up, often assuming almost a spiral form ; and are rendered very distinctly visible by the dark margin which their great refracting power gives them. Their branchings are generally dichotomous, and the processes thus given off are of a size which nearly equals that of the original stem ; and they may often be traced to their union with neighbouring ones, so as to form a kind of trellis-work.\nThe first form exists alone in tendons, ligaments, and the stronger fasci\u00e6 lat\u00e6 ; its inextensibility and strength admirably adapting it to the use of mere passive resistance to an external force. The second is highly elastic, whence it is often termed \u201c the elastic tissue it is chiefly found where, along with a certain amount of yielding, is also required a complete restoration of the previous state without any further expenditure of muscular force, the long duration of an action often rendering it advantageous to avoid the fatigue which the constant exercise of volition and muscle would imply. And as these conditions are much rarer than the simply mechanical wants which the preceding form is destined to supply, so also is the tissue which fulfils them, being found separately in but a few parts of the body; viz. in the ligamenta subflava, and in certain portions of the vocal and respiratory apparatus. Here it is in sparing quantity ; but in the vast ligamentum nuchas, which suspends the ponderous heads of the horned graminivora, the uses of the tissue are exemplified in a very striking manner.\nChemically, they are distinguished by the white fibrous tissue containing much gelatine, or rather yielding it by boiling ; while, from the yellow, none can be obtained. They are both little disposed to putrefaction, and retain their peculiar physical properties almost unimpaired by time.*\n* In an Egyptian mummy, I lately found these tissues (after moistening) displaying as perfect a structure as a specimen of yesterday cculd have done.","page":512},{"file":"p0513.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t513\nA mixture of these two elements constitutes the areolar tissue, which enters so largely into the formation of almost all the organs. The bands of the one and the fibres of the other are closely interwoven, although without mutual continuity ; each giving oil'branches which again unite with the other neighbouring subdivisions of the same kind, so as to form a complicated interlacement of the two networks. This arrangement results in an innumerable series of meshes, which everywhere communicate with those in their immediate proximity, and the size and shape of which varies within very wide limits. And these limits are frequently still further extended, since the separation of some of these microscopic meshes, and the approximation and condensation of others, gives rise to the formation of a secondary net-work, which is visible to the naked eye, and which, though still open in every direction, possesses, especially in inflated and dried preparations, an appearance sufficiently resembling that of cells to remind one of the name formerly applied to this structure, which was called, as if tear f\u00c7oxvv, \u201c the cellular tissue.\u201d\nThe proportion in which these two constituents are mixed varies greatly in the areolar tissue of different parts of the body ; the preponderance of one over the other following that of the conditions which were previously stated to regulate their separate presence. Thus, the likelihood of its frequent and great distention is often a requisition of increased elasticity, and is then accompanied by an increased proportion of the yellow element.\nSimilarly, the amount of this compound structure present in different parts appears to depend mainly on its uses.\nIts offices of uniting the different textures, and of convoying the vessels and nerves, render it necessary that more or less of the tissue should always be present on the exterior of an organ ; and the same circumstances would lead us to expect a slight penetration of its surface.\nIn the interior of organs, however, its absence is by no means infrequent, and is very significant of its use. Thus, the minute elements of the osseous tissue are physically insusceptible of movement; the permissive and facilitating structure becomes unnecessary and impossible ; and is therefore absent. The highly delicate nervous pulp not only possesses no inherent mobility, but, by the extreme delicacy of its structure, offers a physiological obstacle to movement of equal importance with the preceding, and is accompanied by a similar absence of the tissue. The intimate mutual connection of the muscular fibres of the heart, and their association in a common and nearly simultaneous movement, is associated with a like deprivation of this interstitial structure. The same absence at once of the necessity and of the tissue is seen in glandular organs, the situation of which shields them from injurious external force, as appears to\u2019be the case with the liver.\nBut where opposite circumstances obtain, VOL. IV.\nwhere extent and variety of movement imply considerable mobility of the neighbouring muscles of a limb, or situation exposes an organ to external violence, a large quantity envelopes these different textures, penetrating between the different muscles and isolating their several fibres, or breaking up the gland into numerous subdivisions, moveable on each other : of this latter, the mamma is a familiar instance.\nA similar relation might be traced in the wider circumstances of its application. Not only does it form a web of union to the whole body, but it also presents a special layer of considerable thickness, which invests its surface, and partitions which isolate its muscles. And something of a corresponding minimum is found in those animals whose locomotive movements are few and simple, or whose situation and habits little expose them to external violence. So that a rough gradation might be traced through fishes, cetaceans, and reptiles, to mammals ; in which last class man stands pre-eminent in the number and complexity of his voluntary motions, and in the remarkable amount of this subservient tissue.\nAn increase in the freedom of movement of contiguous parts is associated with an increased laxity of this web, the meshes of which become both longer and wider, so as to be more capable of stretching. They thus allow a greater amount of separation to take place between the parts which are attached to the extremities of their irregular net-work.\nBurs\u00e6.\u2014 Here and there throughout the body, where integument or tendon glides over a bony prominence, a further provision occurs, as the development of distinct cavities, which are lined by a smooth shining surface. By dissecting their parietes from the surrounding looser cellular tissue, they may be artificially exhibited as a membrane ; and hence these sacs, closed at all points of their circumference, have received the appellation of burs\u00e6. In the majority of instances, their interior is almost void of contents ; but, in exceptional cases, they contain a considerable quantity of a glairy, mucus-like fluid, which closely resembles that before alluded to, as naming, from its consistence, the synovial membranes. This similarity of their contents was till lately supposed to be the only analogy borne by these structures to the synovial membranes of the articulations ; and hence they have been included by Henle* and other systematic writers in a class of \u201c Pseudo-serous membranes,\u201d and characterised as lacking an epithelium on their inner surface.\nReichert f, however, detected a layer of nucleated cells lining their interior. He stripped off a fine layer from this surface under water, and, upon expanding and compressing it, found that it was covered by numerous darkish nuclei, of somewhat elongated shape, and upon which acetic acid\n* Allgemeine Anatomie, S. 364.\nf M\u00fcller\u2019s Archiv., 1843. Jahresbericht f\u00fcr Mi-kroscopisch Anatomie, S. 339.\nL L","page":513},{"file":"p0514.txt","language":"en","ocr_en":"514.\tSEROUS AND SYNOVIAL MEMBRANES.\nexerted its ordinary effect; defining their outline, and deepening their colour. But although the existence of a stratum of nuclei was sufficiently distinct, the contour of the cells themselves he does not seem to have determined.\nThe resemblance of these burs\u00e6 to the membranes which form the especial subject of this article is thus rendered so complete as to deserve a brief notice of their structure in this place ; and the more so, perhaps, that the writer is enabled to add a few details which place this similarity in a still more striking light.\nThe subcutaneous burs\u00e6 are the simplest form of these structures, and are very numerous in the human subject, but seem much less frequent in other animals.\nThe areolar tissue which immediately invests these sacs is, for the most part, very lax, and contains an unusual quantity of the yellow fibrous element, the fibres of which are here * of large size.\nOn removing this from the outer surface of the bursa, it is seen to be composed of a more compact and whiter tissue, which is tough and much less extensible than the looser texture which surrounds it. The microscope show's this to consist of the white and yellow fibrous tissues. The latter is generally in much less considerable proportion than in the ordinary areolar tissue, while at the same time its constituent fibres are of a smaller size : they possess their ordinary arrangement, and branch and unite sparingly with each other.\nThe white fibrous element is disposed in wavy bands of varying size. These take a course parallel with the surface of the bursa, and, apparently, with few interstices or reticulations ; thus forming a dense laminated structure, which cannot be broken up without much difficulty. In this structure, at a little distance from the interior, are arranged the blood-vessels, the capillary meshes of which are of tolerably large size, and generally take a more or less quadrangular shape. It is by no means unusual to find one, two, or more fat cells lying comparatively isolated in this mass of tissue, with a loop or curve of capillary thrown around them in the ordinary manner. Of the nerves of these membranes I am not qualified to speak. As the white fibrous tissue approaches the internal or free surface which limits the cavity, the bands appear somewhat to differ from this description, and become more refractile, acquiring a yellowish colour, and seeming more solid.\nThe interior of the bursa forms a cavity which is very rarely a solitary and regular one, being almost always complicated by the possession of membranes and threads, which run across its interior, and thus shut off incomplete secondary cavities. The number and situation of these is quite irregular in different subjects ; and, of the two complications, the first is the most common, giving rise to the production of folds, which project into the general cavity in a manner which maybe compared to those processes of dura mater, which\nform the tentorium and falx cerebri. The surface itself is hard and smooth, and the blade of a knife removes little or nothing from it by scraping with any ordinary force.\nIt deserves to be stated that in examining different specimens differences are seen, both in the amount of the yellow or elastic tissue, and in the degree of condensation of the white element, which ought to be called considerable, i. e. that they seem to range, from tough, inextensible, white sacs, of comparatively simple form and composed of little but white fibrous tissue, to a highly elastic membrane, containing a tolerable quantity of the yellow fibrous tissue, and a cavity much complicated by numerous threads and processes. How far these diversities are associated with differences of age or habit, it is impossible to state.\nThe whole of this internal surface is covered by a cell-growth, but the exact shape and arrangement of the constituent particles are rendered difficult of observation by one or two physical peculiarities not devoid of interest. On examining the free aspect of a thin horizontal section, made just below the surface, the dark mass of fibrous tissue upon which the cells are placed, obscured and intersected by the numerous lines which mark its fibres, very seldom allows more than a layer of nuclei to be observed. And the application of acetic acid, which swells up this tissue, and renders it transparent, at the same time dissolves the cell-wall, and leaves the dark nucleus alone occupying its place. On the other hand, scraping the surface, instead of obtaining a layer of cells, mutually adherent by the adapted sides of their polygonal _ margin, and easily separated from the subjacent tissue, as is the case with the serous membranes, \u2014 instead of this, little or nothing is stripped off, save a few scattered cells with much d\u00e9bris and many oil-globules. If greater violence be used, a portion of the subjacent structure is torn off, and offers the same optical difficulties as the thin section alluded to.\nThe careful and repeated examination of different portions and fragments, both with and without the application of dilute acetic acid, leads to the following results.\nI have been unable to verify the existence of a basement membrane, although, on analogical grounds, it might perhaps have been expected that such a structure was present. On getting a favourable view of a vertical section, the surface immediately beneath the epithelium appears to be smooth and defined ; but there is nothing which resembles the other surface of a membrane intervening between the cell-growth and the fibrous tissue. The latter appears to be immediately subjacent to the cells, and is continued outwards without any interruption to the surrounding areolar tissue, in which course it is subject to the modifications already described.\nIn one instance only many elongated nuclei were observed, which were of extreme delicacy, and were seated upon or in a mem-","page":514},{"file":"p0515.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\nbrane of little more than their own breadth ; this membrane was prolonged at their opposite poles into ribbon-shaped processes, of excessive tenuity and considerable length. Such a description greatly approximates to that given by Mr. Goodsir *, of the torn-up \u201c germinal membrane \u201d of the serous tissues ; but I have not studied these objects sufficiently to be able to affirm or deny the complete applicability of his description to them. In the instance where I saw it, I rather inclined to consider it a distortion and elongation of the ordinary epithelia, due to accidental mechanical violence, inflicted during the examination of the specimen.\nThe characters of the cells. \u2014 The different individual cells which may be found floating in the field of the microscope exhibit great diversities of appearance, so as to offer almost every gradation of cell-growth. The first form visible (fig. 396. a) is that of a delicate pale, flat, cytoblast, which is either unaffected by the application of acetic acid, or is even rendered somewhat more transparent by it. The next gradation (b) is still a cytoblast, i.e. uncomplicated by the addition of an outer cell-wall ; but dilute acetic acid renders it yellowish, and much more distinct. In the next variety (the next stage of development, I think it may safely be termed), two outlines\nFig. 396.\nEpithelium, of the Subcutaneous Bursce. (Magnified 320 diameters.')\nare visible (c), one of the nucleus or cytoblast, another of a cell-wall exterior to this ; and the distance between the two gradually increases in different individuals by an increase in the size of the cell, which, however, retains its flattened oval shape. Its contents are either transparent, or very faintly granular : and the succeeding modification mainly consists in the increased granularity of the contents of the cell, and in the assumption of a more or less polygonal outline. This is seen in the figures marked d, e,f g ; and these diagrams also illustrate another detail, viz. that the polygon is anything but a regular one, offering a variety of forms, some of which approximate to a triangle, others to a trapezium or a pentagon. And though sometimes (as in those marked e), they may be seen apposed in groups of two or even three, yet it will be recollected that many of these forms are physically insusceptible of the neat tesselated adaptation which is seen in the hexagonal cells\n* Anatomical and Pathological Observations, p. 41.\n515\nof serous membrane. The wall of the cell is still soluble in acetic acid, and the outline of the nucleus is darkened by its application as usual. The subsequent alterations consist in a gradually increasing flattening and widening, both of the cell and nucleus, but especially of the former, which finally more than doubles the diameter of the polygonal cell, and at the same time reduces its depth to a mere scale. The granular or mottled appearance of the contents before spoken of now reaches its maximum, often forming yellow refractile dots or beads, which appear to be incompletely fluid (h). The nucleus, during this process of flattening, becomes somewhat larger, and much less distinct; and in the larger and more mottled scales, it completely disappears, an effect which might at first be supposed due to the obscuring of its outline by the granular contents, but which is evidently independent of this cause. A further difference is presented by the action of acetic acid, which fails to affect these broad squamous epithelia in any perceptible degree.\nThe arrangement of the cells. \u2014 Elitherto we have merely enumerated and distinguished the different forms of cell-growth which may be detected after tearing up casual portions of the tissues lining the cavity : we have next to determine the relative quantities of the different varieties, and to specify their arrangement, both with respect to each other and to the surface which they clothe.\nThe forms which appear greatly to predominate in quantity, are those represented in the figure as c, d,f. Some of these are nucleated cells of a flattened oval shape, and others are probably similar cells, in a stage immediately subsequent to the preceding, when the oval vesicle becomes more or less angular by the lateral pressure of its neighbours opposing its own inherent expansion ; or, regarding a number of such bodies, when a simultaneous expansion obliges their yielding walls to adopt that shape which presents the fewest interstices, and thus allows of the greatest amount of mean area. Were the process conducted with mathematical accuracy, this shape would obviously be a hexagon, and in the serous membranes it will be seen with how few exceptions the cells approximate to that form ; but in the outline of these bursal epithelia, as has been already seen, the oval or circle glides into the polygon by many gradations.\nGenerally speaking, there is but one layer of cells, and these are usually more or less polygonal ; but not unfrequently a few oval ones are seen in close proximity to each other, and only distinguishable by the smaller distance between their nuclei, and the occasional overlapping of their curved borders.\nThe chief exceptions to the unity of the layer are twofold, one at each extremity of the cell-life, so to speak. For instance, pale flat cytoblasts (a), in sparing quantity, sometimes underlie the stratum ; while, on the other hand, it is often covered by the very large polygonal squames (h). In either case,\nL L 2","page":515},{"file":"p0516.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\n516\nit is almost impossible to observe both these different layers in situ, from the transparency and flatness of the objects just named causing them to be effectually shrouded and lost in the outline of the granular polygonal layer ; but, from various reasons, 1 have little doubt that the preceding description may be regarded as tolerably correct. It is especially countenanced by these facts, that in looking directly upon the free surface, 1 have never seen cells referrible to either of the two extremes, but always such as from their shape, their size, and the mutual distances of their nuclei, would be included in the varieties (c, d,f ) ; while, nevertheless, a careful tearing up of the same specimen often afforded the cytoblasts and scales. The latter were in much greater quantity than the former, but whether they existed over the whole surface of the bursa, or on particular parts only, I am unprepared to state. And whether the cytoblasts chiefly underlie the oval or the polygonal forms, is a question equally impossible to answer satisfactorily, yet by no means so insignificant an inquiry as it may seem at first sight. On the whole, their usual appearance in conjunction with the younger forms, and their comparative absence from the polygonal-celled serous membranes, somewhat tend to associate them more with the oval than with the polygonal epithelia.\nThe subtendinous burs\u0153. \u2014 It frequently happens that, where tendons in passing to their insertion lie upon a bone, the action of the muscle with which they are continuous gives rise to considerable friction of the two surfaces against each other : and, in some cases, the projecting surface of the bone is even made the pulley by means of which the direction of the muscle\u2019s action is altered, through a similar change in the course of the tendon ; a condition which necessarily implies a yet greater amount of resistance and friction. In these circumstances, bursae are found interposed between the osseous and tendinous surfaces. These bursae have* hitherto been regarded as in all respects similar to the subcutaneous sacs just described, and the possession of an epithelial lining has been denied them equally with these. But while they apparently present the same form, that of a shut sac, continuous with itself in every part, and are, in the majority of instances, indistinguishable from them by the naked eye, they are yet separated from them by important differences. They present, it is true, a cell-growth analogous to that described in the preceding structures ; but they\n* Since writing tlie above, I have been informed that a description of these structures, somewhat resembling that given by the writer, has appeared in a provincial German periodical of a few months\u2019 earlier date. I have been unable to meet -with it however. So also, the account which I have given of Synovial Membranes must not be understood as claiming any priority. I believe that priority (and probably something more) belongs to Mr. Rainey ; a report of whose paper has appeared in the \u201c Proceedings of the Royal Society,\u201d a publication which I have found difficult of access.\ndiffer from these in the extent of surfac eon which that growth obtains, in the nature of the tissues which are substituted where it is absent, and, in a lesser degree, in the general characters of the membrane where it is present : the general effect of these differences being greatly to liken the anatomy of these structures to that of the joints.\nOn laying open one of the least complicated of these bursae, such as they are generally seen in the dog and cat, we gain entrance to a simple cavity, which everywhere possesses a smooth and shining interior. Above is the tendon, below the periosteum of the bone ; on either side, a delicate continuous membrane separates it from the neighbouring areolar tissue. It might be expected that this membrane covered the neighbouring opposed surfaces of tendon and periosteum ; and, indeed, the description usually given by authors affirms the existence of such a covering, to which it attributes the smoothness of their surfaces. But this is not the case : a careful examination of these structures with the microscope distinctly shows that their surfaces of friction are quite devoid of this membrane, and have assumed more or less of the structure of cartilage.\nThe membrane, then, may be described as preserving the continuity of the inner surface of the burs\u00e6 in the interval between the two rubbing surfaces. It is attached to the tendon and periosteum by a mingling of its areolar tissue with these structures. Like its neighbouring areolar tissue, it is extremely elastic and delicate ; so that its tenuity often equals that of the serous membranes. It is plentifully supplied with blood-vessels; and, generally, there is a considerable amount or adipose tissue on its attached surface, the capillaries of which are arranged in the same manner as those in the bursae previously mentioned, or those which supply the fat cells of the so-called \u201c Haversian glands \u201d in the joints :\u2014viz. the same capillary plexus, which immediately underlies the epithelium, gives off occasional loops to surround the adipose vesicles. The epithelium itself resembles that of the subcutaneous bursae in the intimacy of its adhesion to the subjacent tissue, as well as in the comparatively slight connection which subsists between the cells themselves : but it appears to differ from it in the greater quantity of the oval cells and cytoblasts, of the former especially : and in the immediate neighbourhood of the fat vesicles this shape seems to predominate to the comparative exclusion of polygonal forms.\nIn the human subject, the surface of bone on which the tendon plays often presents a covering of what has all the appearances of fibrous tissue mingled with cartilage, or \u201c fibro-cartilage and even in smaller animals (as the cat), in whom the tissue offers no visible difference from the neighbouring periosteum, its intimate structure exhibits a similar transition. The bursa beneath the tendon of the obturator internus, where this turns over the border of the ischium in its p-o-","page":516},{"file":"p0517.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t517\ngress towards the trochanter of the femur, is a convenient one for examination. On making a thin section parallel to the osseous surface, it is found that the bands of the white fibrous element which constitute the periosteum are considerably changed where they line the burs\u00e6. They are much less wavy than usual, and, at the same time, have become much more brittle and transparent. Besides becoming more linear, the markings have altered in another respect, viz. they are much less frequent, and are placed at more regular distances. The ordinary epithelium which elsewhere lines the cavity has disappeared, and, in its stead, we recognise a great number of cells irregularly scattered over the surface of the specimen; although even now one may perhaps trace an approach to a longitudinal arrangement in their greater proximity in this direction. These cells, in respect of their solidity, their somewhat angular shape, their colourless transparency, and refractility, greatly resemble those seen in articular cartilage. They are, in fact, cartilage corpuscles. But although exactly on the surface these cells are somewhat flattened, and scattered with comparative irregularity, this appearance by no means extends any depth in the tissue. A slight alteration of the focus shows that, immediately beneath the surface, corpuscles are not only less numerous, but also assume a distinctly linear arrangement; and form somewhat interrupted longitudinal rows, which chiefly occupy the interstices of the altered bands of white fibrous tissue. The corpuscles themselves are here more angular and elongated. By further altering the focus, and obtaining a deeper view, the lines marking these surfaces are seen to be crossed by others ; and a closer inspection reveals the existence of two strata : one, the superficial layer just examined, of which the lines are in the direction of motion, or transverse to this border of the ischium ; and another deeper layer, which lies at right angles to the preceding, and immediately covers the bone. In the latter, the same corpuscles exist, but in rather fewer numbers. The application of acetic acid slowly swells and dissolves the intercellular substance, and renders the cells more distinct, but does not deepen their colour. After a considerable interval of time, it attacks the corpuscles themselves, and renders them invisible ; apparently more from its effect on their relations to the refractility of the surrounding substance, than from a real solution.\nIn like manner, the under surface of the tendon offers a similar cellular structure, and a corresponding, but much less considerable, modification of the fibrous tissue itself. But this change, which, on the surface, is so well marked, gradually diminishes as one examines successive and deeper horizontal sections; and, finally, at a certain depth, the intercellular substance altogether loses its cartilaginous characters, the cells themselves vanish, and the tendon completely resumes its ordinary structure.\nThe crossing of two strata at right angles to each other, which is witnessed in the modified periosteum, is a frequent anatomical peculiarity of the original tissue, and not essential to the modification. And something very similar is seen in the tendon. The tendinous bundles to which the several muscular fibres are attached, are successively received into the border of the oblique tendon; and very frequently, in joining it, a\nFig. 397.\nUnder or Bursal Surface of Obturator Internus Tendon. From the Cat.\na, superficial stratum ; b, deeper layer lying at an oblique angle to the preceding. (.Magnified about 180 diameters.')\ncertain proportion of their fibres swerve aside from its track, scatter themselves, and strengthen the cord as a whole, by crossing its surface at a varying angle, and forming a thin stratum superficial to it. Where the tendon assumes the peculiarities just alluded to, the markings and corpuscles of this superficial layer are seen decussating those of the larger and deeper mass which take the direction of the tendon. This crossing of two strata is indicated in fig. 397.\nThe chief differences between the cells on the surface and those at a greater depth have been already indicated ; viz., that the former are more numerous, flatter, and more oval. But the shapes and appearances of the deeper layer deserve further consideration, since they present the phenomena of a fissiparous genesis of cells, which the upper stratum does not; so that it is perhaps difficult to avoid attributing the increase of numbers and alteration of shape which is seen near the surface to the gradual advance of the multiplied corpuscles in that direction. The stages of the process are the same as may be observed in other tissues. An elongation of the nucleus is followed by an hour-glass constriction of its middle ; a dark line across the corpuscle then testifies to the fission of both cell and nucleus ; and, finally, the two new cells separate, and their walls surround the nucleus at a more equal distance in every part. Most of these steps may be observed in fig. 397.\nL L 3","page":517},{"file":"p0518.txt","language":"en","ocr_en":"518\tSEROUS AND SYNOVIAL MEMBRANES.\nThe conjecture just mentioned derives considerable support from a comparison of their structure in the adult with their younger and foetal conditions in the same animal. In the latter especially, the quantity of cell-growth on the surface is so great, as, in respect of mere continuousness, almost to merit the appellation of an epithelium. But though its constituent cells lack the angularity, and somewhat the size, of those which belong to the inferior strata ; yet, like the same cells in the adult, they are quite distinguishable from the epithelial covering of the bursa, not only by their appearances with and without acetic acid, but by the distance to which the shifting focus follows them. At successive depths, they are seen to become somewhat larger, more angular, and wider apart ; and the same process of fissiparous multiplication may be detected in them as in the adult cells. We shall see that these differences at the different stages of the animal\u2019s life experience a close parallel in articular cartilage.\nIn a few instances, I have witnessed another form of cell-multiplication in this tissue. It occurred in one or two cats of a few months\u2019 age, but I cannot say whether it is limited to any particular period of their life. It is represented in fig. 398, and con-\nFig. 398.\nCompound Cells of Bursal Fibro-cartilage. From the young Cat. (Magnified 400 diameters.')\nsists of an oval or elongated vesicle or cell of limitary membrane, which is filled with, and usually more or less bulged by, a number of cytoblasts. These compound vesicles were sparingly scattered through the cartilage-like tendon and periosteum ; similar masses of cytoblasts, of a spherical form, may occasionally be seen in young articular cartilage ; and, indeed, instances of this form of cell-multiplication might be adduced from many structures, temporary, permanent, and morbid, but their introduction would be foreign to the province of this article.\nThe constitution of the synovial sheaths of tendons resembles that of these bursae in many respects ; and, on the whole, offers a still closer approximation to the structure of a joint. In many places, the sheath consists only of a delicate transparent membrane, the tenuity of which approaches that of the serous membranes, and which, like them, rests on a stratum of loose areolar tissue, and is reflected from the parietes of the cavity to the tendon where it enters it. Here they possess an oval or slightly angular epithelium, which constitutes only one layer. But almost\nevery such tendon, in some part or other of its course, offers an alteration of direction implying considerable friction, and effected either by a projection of bone, or by a pulley of thick and strong fascia. Such are the grooves and posterior carpal ligament for the extensors at the back of the wrist. And here is again discovered the condition which was previously stated of the obturator tendon, but with some slight modifications ; firstly, that the approximation to the structure of cartilage, here visible to the naked eye, affects equally the whole periphery of the tendon, instead of being limited, as heretofore, to one of its surfaces ; and, secondly, that the cell-growth is more plenteous, sufficiently so as to offer scarcely a point of the surface unoccupied by cells ; of which the shape, size, and disposition almost exactly resemble those of the surface of articular cartilage in the young mammal or the adult reptile.\nIn the cartilaginous-looking portions of the sheath, a similar, but less extensive depth of cell-growth obtains ; and I believe I have recognised the same condition in the surface of the crucial ligaments of the knee-joint.\nThe vessels of these synovial sheaths are very numerous, and their capillaries exhibit a tortuous arrangement which is identical with that witnessed in the articular synovial membranes hereafter to be described. But this copious supply of vessels is limited to the delicate membranous portions of the sheath, and to those mesentery-like reflections which here and there pass from the parietes to the contained tendon. Wherever the tendons are subject to much friction, and evince the partially cartilaginous structure already described, there the vessels are absent from those superficial and cell-containing strata, and, so far as I know, are limited to the deeper and non-cellular parts of the tendon.\nSynovial Membranes. \u2014 The synovial membranes are structures exceedingly analogous to the preceding, and consist of a layer of cell-growth, which covers the inner surface of the ligaments that connect the different segments of the skeleton in the diarthrodial joints, and which thus partially lines the \u201c cavity \u201d or interior of these articulations.\nThey have been usually described as resembling the burses mucosce both in the nature and consistence of their secretion, and in their constant adherence to the morphological character of a shut sac ; while the absence of epithelium predicated of these bursae, has been laid down as the chief anatomical distinction between the two structures. And, on the other hand, they have been likened to the serous membranes by the common possession of a tesselated epithelium, and by their continuity over the whole surface of the cavity and its contents ; while they have been severed from them by the difference in the composition and consistence of their secretion,\u2014a viscid alkaline fluid, instead of a more limpid and neutral one. Most of these statements can only be received with some modification.","page":518},{"file":"p0519.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\nIn the following sketch, such details as are more or less common to the synovial membranes in general will chiefly be treated of. For a description of their more salient peculiarities in the different joints, the reader is referred to the articles headed with the names of the several articulations.\nThe epithelium of these structures presents characters which afford some grounds for distinguishing it both from that of the bursal and serous membranes. It forms, for the most part, but one layer, the forms of the constituent cells of which vary to the same extent as those witnessed in the burs\u00e6. But the broad, squamous, polygonal epithelia are comparatively rare ; and in by far the larger extent of its surface, the predominant shape is that of a slightly flattened spheroidal, or oval, or somewhat angular cell, such as the majority of those represented in fig. 399, in\n519\nThe vessels of the membrane are exceedingly numerous, and its capillaries form a horizontal plexus, which ramifies immediately beneath the epithelium in the areolar tissue just mentioned. The great vascularity of the tissue has long been known, but the capillaries are not only very numerous, but offer a much more remarkable peculiarity.* They are greatly increased in their length, so as to be everywhere extremely tortuous, and sometimes this tortuosity almost amounts to a spiral disposition. On looking at the broad surface of well-injected specimens, an exaggeration of this disposition here and there, gives rise to small patches of tortuous capillaries ; but the arrangement is clearly a general one, and extends, in some degree, to every individual capillary of the net-work. But though the length of these vessels in a given space is thus greatly augmented, the frequency of their\nFig. 399.\nEpithelium of Synovial Membranes, a, free surface seen in situ. ; b, separated cells. (Magnified 200 diameters.')\nsome of which are seen decussations of two convex outlines, caused by the margin of one cell slightly overlapping that of its neighbour. Acetic acid exerts an unusual effect upon the cell-membrane, swelling up its outline very much before dissolving or rupturing it; an appearance which obtains in the more flattened and polygonal epithelia of the serous membranes, but, so far as I have seen, in a much smaller degree. Like those of the burs\u00e6, they are firmly attached to the subjacent tissue, and possess little mutual adhesion ; though here and there a cluster of two or three more polygonal than usual may be found. Cytoblasts are rare, the cells appearing to be completed by the addition of the outer membrane when yet extremely small, (fig. 399. h.)\nAll these peculiarities might perhaps be generalized in the statement, that the cells which cover the general surface of these membranes are in a younger and more active stage of cell-life than those of the burs\u00e6. And a slight yet perceptible difference in the same respect has been already indicated as existing between the subcutaneous and sub-tendinous members of this class of structures. Immediately beneath these cells lies a stratum of looser areolar tissue, which connects the membrane with the inner aspect of the ligaments of the joint. It includes little of the yellow fibrous tissue, and its meshes are comparatively few and close : exteriorly, they unite, by a gradation of structure, with the dense white fibrous tissue of which the ligaments are composed.\nFig. 400.\nCapillaries of the Synovial Membrane, projecting by\ntheir convex border over the articular cartilage.\nFrom the human finger.\na, artery ; v, vein. (Magnified 40 diameters.)\ninosculations does not seem to experience a corresponding increase. Their tortuous form is represented in fig. 400.\nThe preceding description of the vascular, fibrous, and areolar constituents of synovial membrane applies only to the simplest form of that tissue, which consists of a plain flat expanse of membrane. In special joints, as well as in special parts of every joint, each of them experiences modifications deserving of notice. Over the cartilage of the articulation, for instance, all of these cease ; and deferring for the present a consideration of the analogous structure which here supplies the place of epithelium, we come to consider the anatomy of the synovial membrane where it reaches the border of articular cartilage.\nThe fibrous tissue exterior to the mem-\n* I have here to express great obligations to Mr. Quekett, of the Royal College of Surgeons, since his kindness supplied me both with specimens, and with many further details of this arrangement, till then unknown to me. The joint from which fig. 400. was sketched, was taken from a hand admirably injected by him.\nL L 4","page":519},{"file":"p0520.txt","language":"en","ocr_en":"520\nSEROUS AND SYNOVIAL MEMBRANES.\nbrane, and with which its areolar tissue is mingled, passes to the side of the articular cartilage, and immediately becomes inextricably interlaced with its fibrous tissue or perichondrium. The plexus of capillaries, somewhat more tortuous here than on the plain surface, runs up to the edge of the cartilage, or may even advance a very short distance over it, where it is not exposed to friction during the movements of the joint. Its various branches then suddenly stop short, and each taking a looped course, returns upon itself in the same tortuous manner. This distribution is represented in\u00dfg. 400.\nThe layer of epithelium offers equally remarkable appearances ; a few of its particles are very slightly flattened, but most of them are spherical, and of very various sizes, of which some are extremely large. All of the larger contain a pale and rather flattened nucleus, which is in contact with a part of their inner surface. The cells are also of singular delicacy and transparency, and are, to all appearance, distended with a fluid, the refractility and colour of which closely approximate to that of water. The areolar tissue which forms the foundation of the membrane being diverted at this point to join with the ligaments and perichondrium, the vessels are left comparatively naked ; and so far as I have been able to make out, upon these bare capillaries the cells are seated, without the intervention of any membrane. They thus form what is indeed a covering for the vessels (since there is no part of them upon which large or small cells or cytoblasts are not placed) ; but, as is evident from their shape only, they constitute a layer in a very different sense from those in which the epithelium of the serous membranes does so.\nIn some of the more complex joints, another modification occurs, which is in many respects very similar to this, viz. distinct folds or involutions of synovial membrane, which project into the cavity of the joint. The best instances of this are seen in the knee-joint, where they form what are called the \u201cmucous\u201d and \u201c alar ligaments.\u201d The folds which constitute these come off horizontally from the synovial membrane in the front of the articulation, but with a considerable interval between their upper and lower layers, which is filled with adipose tissue. They contain besides, a plexus of vessels, of which some, lying immediately beneath the membrane, ramify in the flexuous manner described ; while the deeper are distributed to the fat vesicles, throwing loops around each in the manner peculiar to this tissue. A very small quantity of fine areolar tissue is present, chiefly as a covering and protection to the vessels. Gradually going backwards, they lose their adipose tissue, and taper to an edge, which accurately fits into the interstice between the condyles of the femur and head of the tibia. Here the upper and under layers come into contact, and in the middle line pursue their way backwards as the ligamen-tum mucosum, a flat, thin duplication of the\nmembrane ; until, finally, at the anterior termination of the notch between the condyles, they terminate by joining the synovial covering and fibres of the neighbouring crucial ligament. On either side of the middle line, the process of synovial membrane terminates, by a convex margin, a little beyond the point where it ceases to contain fat : these are the \u201c alar ligaments.\u201d\nOn the ligamentum mucosum, the cells are of a similar appearance to those of the general surface of the membrane, though they seem rather more delicate and transparent.\nThe projecting edge of the so-called alar ligaments offers still more marked characters. Owing to the congestion of its vessels from some unknown cause, it is frequently seen after death of a bright red colour, its surface is minutely rough or velvety, and its consistence soft or almost pulpy. On examining it with the microscope, many minute and villuslike processes are seen studding its border, and directed backwards towards the commissure of the femoral and tibial articular surfaces. These processes appear to consist chiefly or entirely of two structures, viz. bloodvessels and cells. The vessels are numerous long tortuous capillaries, which pass to the margin of the villus, and then, taking an arched or looped course, return upon themselves, and pass, with few anastomoses, into the general plexus of the fold. The cells, equally with the vessels, resemble those already described as existing at the border of the articular cartilage. They are of various sizes, the more numerous and larger ones are spherical, transparent, and contain a tolerably large nucleus : they are distended with fluid, and the slightest pressure on their singularly delicate cell-wall bursts the cell, and causes the fluid to exude. In this condition, the action of the surrounding water seems to impress on it something like a partial coagulation, giving it a mottled or minutely granular appearance.\nThe smaller cells exhibit the same shape and general appearances, except that the nucleus is proportionally larger ; a few cytoblasts are also present, and a granular blastema completes the covering of the vessels. One would fancy this to be a favourable situation for verifying the existence of a basement membrane, did such a structure exist here ; but I have been unable to detect it. On the contrary, I have often seen the curved border of a large cell seated directly on a capillary, the dark line of the wall of this tube alone separating its cavity from the delicate sphere in contact with it.\nMg. 401. represents such a villus-shaped process.\nThe relation of the synovial membranes to the diarthrodial cartilages, or the question of \u201c Whether the membrane is continued over the articular surface of the cartilages, or not?\u201d has been long a matter of dispute among anatomists. But a resume of the history of this discussion having been already given in an earlier part of the work, the reader is","page":520},{"file":"p0521.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\nreferred to it for a statement of the arguments on both sides of this interesting question up to that date. (See Articulation.)\nThe rapid progress of histological anatomy, and the use of the microscope, have since thrown much light on the subject, yet perhaps with a less immediate effect than might have been anticipated.\nFig. 401.\nVillus-shaped process from the free Margin of the Alar Ligament. From the Cat. (Magnified 300 diameters.)\nFrom the impossibility of injecting the vessels of the synovial membrane beyond the margin of the cartilage, it had long been known that they did not extend over this articular surface ; and one might almost imagine that a looped termination of the vessels in this situation must have been suspected. And the researches of Mr. Toynbee* concerning the vascular arrangements of the deep or osseous surface of the cartilaginous lamina, showed a similar disposition of the vessels in this situation. Everywhere a thin plate of bone, impermeated by vessels, separates them from actual contact with the cartilage ; and the capillaries themselves, as they approach this osseous lamella, appear somewhat dilated, and finally, taking an arched course, they return upon themselves into the neighbouring extremity of the bone. The truth of this description as a whole is readily tested and confirmed by examining any part of the substance of a diarthrodial cartilage. Such a fragment, torn up in any manner, and submitted to a sufficiently high magnifying\n* Philosophical Transactions, 1841.\n521\npower, evinces no trace whatever of vessels, or of their easily recognisable contents.\nBut although the absence of vessels is thus proved, the absence of the synovial membrane by no means necessarily follows. The less so, indeed, that modern physiological research exhibits almost all structures as essentially extra-vascular : i. e. it shows that in almost all, the characteristic substance of their tissue is separated from their vessels by an interval ; an interval which, though always minute, is nevertheless an appreciable, and often a measurable one, and which the pabulum derived from the blood has to traverse in order to effect their nutrition.\nThe continuity of the synovial membrane, or the reverse, can only be settled in one way ; to wit, by an appeal to observation : and since the naked eye fails to give sufficient information, it remains to the microscope to decide its presence on, or absence from the articular surface.\nHenle* affirms the continuity of the membrane over the cartilage, as a tesselated epithelial covering of nucleated cells, resembling those which line the serous membranes and the other parts of the joint.\nProfessors Todd and Bowman in their more recent work)-, state that they have been unable to detect such a covering in the adult, but that, on the contrary, they have usually observed an irregular surface, presenting no cells beyond the ordinary scattered corpuscles of the cartilage. In the foetus, however, they have found it readily visible.\nA comparative examination of those cartilages in different genera of animals, or in the same animal at different stages of life, partly confirms, partly modifies, each of these statements.\nIn a specimen of diarthrodial cartilage, taken from an adult mammal, if we make a thin section parallel to the articular surface, and look directly upon this part of the interior of the joint, we see appearances similar to those represented in fig. 402. A number of cartilage corpuscles, at irregular distances from each other, and separated by the intercellular substance of this tissue, constitute the only cell-formation visible, and the existence of similar corpuscles at varying depths in the substance of the cartilage\" may easily be verified. The chief difference noticeable between the deeper and more superficial of these cells is, that those in the latter situation contain in their interior many yellow and highly refractile granules, which are of comparatively uniform size, and occupy their cavity about midway between their tolerably central nucleus and the inner surface of the cell-membrane. This appearance becomes still more manifest as the corpuscles approach the articular surface. A thin vertical section of the cartilage shows that the cells are in greater numbers near this surface, and the edge which borders the joint exhibits an irre-\n* Allgemeine Anatomie, S. 226, et seq.\nt The Physiological Anatomy and Physiology of Man, vol. i. p. 90.","page":521},{"file":"p0522.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\n522\ngular outline, from which cells may often be seen projecting. The attrition which these appearances would seem to denote appears to be exerted upon the cells equally with the interstitial substance of the cartilage, but is more difficult to verify in the former tissue, since such a cell that has suffered a partial destruction of its form, has, at the same time, lost a valuable optical means of detection. Occasionally, however, as infig. 402., on looking\nFig. 402.\nFree surface of Articular Cartilage. From the elbow-\njoint of an adult Cat. (Magnified 200 diameters.')\ndirectly at the free surface of the tissue, we see a darkish nucleus, lying very superficially, and surrounded by a clear space. In all probability, this was such a cell ground down to a hemispherical cavity. More rarely, a profile view of such a hemisphere is obtained.\nOn examining similar specimens from animals of the same species at successively younger ages, the intercellular substance becomes gradually more scanty, and finally altogether disappears, leaving the whole of the surface occupied by a cell-growth, which is a covering, but not an epithelium, unless we extend the application of this objectionable word, and call the whole cartilage itself, what indeed we might with perfect truth, \u201c a modified epithelium.\u201d\nThe accuracy of this description of the cartilage of very young animals is easily verified by a vertical section ; and, if it be made sufficiently deep, it will include a portion of another structure, and a different process, with which it may be advantageous to compare it. At the furthest extremity of such a section, we see the ossification of temporary cartilage actively going forward. First comes the formation of cancelli, and the enclosure of cells ; next, a little nearer the articular surface, the greatly dilated cells are arranged in closely-packed rows, the bottoms of which rest in cups of bone, which will soon become cancelli. Still approaching the articular surface, we find the cartilage corpuscles smaller, more refractile, and flatter; but yet with a distinctly linear arrangement. The loss of this arrangement in rows seems to indicate the limit of the ossifying cartilage and the commencement of the articular lamina; and I have often seen the distinction still further marked out by a horizontal fissure in this situation, \u2014 the effect of accidental violence, no doubt, but perhaps indicative of some deficiency of cohesion dependent on structure.\nImmediately beyond this situation, the cartilage cells are scattered irregularly but closely through the transparent intercellular substance. They are angular and refractile, and they contain a large granular nucleus. Many of them are elongated, and somewhat spindle-shaped, while many more are triangular; and these two forms appear respectively to precede and follow a fissiparous multiplication of their numbers, the constancy and accuracy of which would almost allow of its being termed a bisection. The details of this process have been already alluded to in speaking of the subtendinous burs\u00e6, and are too well known to need any recapitulation here. From hence onwards to the articular surface, the cells become more numerous, larger, and less angular in shape, until finally, on the surface itself, the increase of their number and size results in a continuous layer. But the appearances of this multiplication are not seen in the most superficial stratum of all, although the prevalence of the hemispherical outline still indicates the binary nature of the fission ; whence it seems probable, that just upon the surface the increase is one of bulk only.\nIn fig. 403. is represented a vertical view of the superficial and of a deeper layer, which contrasts them in the particulars just men-\nArticular Cartilage from a Kitten four days old.\na, arrangement of cells on the free surface ; b, a deeper stratum. (.Magnified about 250 diameters.)\ntioned. The condition of these cartilages in the adult fishes and reptiles closely resembles this description of their appearance in the young mammal, in the complete cellularity of their surface. For the knowledge of this fact, I am indebted to Mr. Quekett.\nSerous Membranes. \u2014 The serous membranes, presenting a structure which offers a close general parallel with that of the preceding tissues, are yet contrasted with them in many important respects. The first and most obvious distinction, and one on which the other structural differences are to a great extent based, is, that in place of their maintaining a direct relation to the locomotive apparatus, or being connected with the segments of the skeleton in the diarthrodial joints, the organs to which they are more immediately subservient are those concerned in the organic or vegetative life.\nThe serous membranes of the human body are seven in number ; three being median and single, while two are double and lateral. They are the arachnoid, pericardium, and peritoneum, with the pleurae and tunic\u00e6","page":522},{"file":"p0523.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\nvaginales. Thus they are connected with the organs of respiration, circulation, digestion, generation, and innervation. Perhaps, under this accurate allotment of serous membranes to these several functions, many important analogies lie hidden, but the interpretation of these hieroglyphics of nature scarcely belongs to the present elementary sketch ; and it will be both safer and more profitable to regard their relations to the three first of these functions as being determined mainly by the necessity of movement which a high development of any one of them implies, although the general protection which mobility affords must not be lost sight of. The relation of a separate membrane to the function of generation seems, as it were, the accidental result of position : the tunica vaginalis, an offshoot of the peritoneum, is prolonged from it by the testicle in its descent from out of the abdominal cavity, and is subsequently isolated by a degeneration of the serous membrane into areolar tissue along the spermatic cord which connects this gland with the interior of the belly. So the arrangement of the arachnoid around the nervous centre is, perhaps, more related to the comparative delicacy of its structure, and the movements inseparable from circulation, than to the function of innervation itself.\nA prominent feature in the anatomy of all these structures is the remarkable continuity of surface which they exhibit. With a single exception, indeed, their interior surface, like that of the subcutaneous burs\u00e6, is everywhere a continuous one ; and hence the definition of a serous membrane always includes the statement, that it is \u201c a shut sac,\u201d while this peculiarity of arrangement is constituted their \u201c morphological character.\u201d\nA complete description of the serous membranes would comprise two chief divisions of the subject. One of these would include the relative situation and arrangement of the neighbouring textures, as well as the various folds or processes by which the membranes preserve their continuity in the intervals between the viscera which they cover and the cavities which they line. The other would limit attention to their general structure ; and to any variations in the nature, proportions, or arrangement of their constituent tissues, which may be obtained by a comparison of the several membranes with each other. In the present instance, the latter only of these divisions will be briefly attempted ; for the former of the two, the reader is referred to the articles under the several headings of Pleura, Peritoneum, Heart, Nervous Centres, Testicle, &c.\nThe epithelium of serous membranes consists of flattened cells. The shape of most of these is roundish-polygonal, and many of them closely approximate to the hexagonal form : and they are arranged in a single layer, so as to form a tesselated pavement, which everywhere constitutes the free surface of the membrane. Their diameter varies\n523\nconsiderably, but, generally speaking, is about one 1000th of an inch. Their depth is nearly one-fourth of this width; but it tapers awajr towards the edge of the particle, and is greatest at its centre, where it is usually somewhat bulged by the presence of a tolerably large nucleus, which is contained in the cavity of the cell, but is placed nearer its inferior or attached surface than the opposite or free one. This nucleus is of an oval or spheroidal form, and contains a single bright refractile spot or nucleolus ; but not unfre-quently there are two of these. Besides the nucleus, the cell includes a small quantity of contents, which are of somewhat viscid consistence, and are usually almost transparent, but sometimes, and especially after exposure to the action of water, become mottled or faintly granular. The attachment of these cells to each other is very remarkable, but their adhesion to the textures on which they are placed is much less considerable ; and this preponderance of their adhesion in the horizontal direction renders it very easy to strip off a number of them, and exhibit the layer which they form by their union. In this circumstance they offer a marked and probably important difference from the cells which clothe the interior of burs\u00e6 and synovial membranes. Acetic acid exerts its ordinary effects, causing the cells to swell out, and thus defining their polygonal shape more accurately than before.\nThe exceptions to these general characters are few. In one instance, namely in the peritoneum of the female, the form of the cellular covering is said to differ from the above; the ciliated epithelium, which lines the Fallopian tubes, being continued for an exceedingly short distance over the margins of their fimbriated extremities. The size of the cells also experiences slight variations : thus, they are largest in the peritoneum, and smaller in the pericardium, especially in its visceral layer. Their arrangement as a single cellular stratum is also interrupted in some parts : thus, the arachnoid exhibits one or two layers, the outer of which is composed of cells which are more flattened and elongated than usual.\nBasement membrane.\u2014The existence of a basement membrane immediately beneath these cells is still a matter of doubt. It rests chiefly on the affirmation of Professors Todd and Bowman, and Goodsir \u2014 high authorities on such a question. By the first of these anatomists it is regarded as \u201c a continuous transparent membrane of excessive tenuity,\u201d and \u201chomogenous, or nearly so.\u201d* The latter describes it in much the same terms, but considers it sometimes, or generally, separable into component cells, which are of a rhomboidal and extremely flattened shape ; and it has been named by him as the Germinal Membrane.\\ As somewhat corroborative of these statements, it may be urged, that such a structure is easily seen to exist in the very\n* Op. cit. p. 130.\nf Ibid. p. 41.","page":523},{"file":"p0524.txt","language":"en","ocr_en":"524\tSEROUS AND SYNOVIAL MEMBRANES.\nsimilar mucous membranes ; and that the cell-lining of the arteries, which becomes deficient where these pass into the capillaries, and thus leaves the latter vessels with a simple membranous wall, seems to exhibit a kind of natural analysis of a yet more similar compound structure. And it must be recollected that failure of recognition is by no means a satisfactory argument against the presence of such a delicate structure ; i. <?. that one such affirmation as those above ought to outweigh many denials. Still those who, after repeated and careful examination, have failed to recognise it, are no doubt justified in continuing to doubt its existence.\nAreolar Tissue.\u2014 A stratum of areolar tissue occupies the outer or inferior surface of the preceding cellular structure, and includes in and amongst its meshes the remaining constituents of the serous membrane. The inner surface of this lamina is smooth and condensed, where it immediately underlies the cells : exteriorly, it can scarcely be considered as possessing a defined surface, but gradually merges into the areolar tissue of the neighbouring organs. The separation of the two structures is, however, generally indicated by an interval, in which their texture is somewhat looser. This is called the \u201c subserous cellular tissue.\"\nAs this layer constitutes the chief thickness of the membrane, and is the constituent on which its physical properties are mainly dependent ; so its varieties of constitution and arrangement, correlatively with the requisite differences of these properties, are both numerous and important.\nOne of the most common of these alterations is an augmented quantity of the yellow fibrous element ; indeed, in many portions of the serous membranes, this increase is so considerable as to constitute a continuous special layer of the elastic fibre, which occupies a horizontal plane immediately beneath the epithelium. The fibres of this layer are delicate, of a smaller diameter, and somewhat paler colour, than those which are found in the ordinary areolar tissue : they branch at acute angles in every direction, and unite with those in the immediate neighbourhood ; while beneath, and partly amongst them, are seen the white fibrous bundles, with their ordinary arrangement. The advantage of such a predominance of the yellow element is obvious : it confers an increased elasticity on the membrane, and better adapts it for distention, or for a return to its original bulk after this force is removed. The situations in which it is found are in exact conformity with this view : in the peritoneum, which lines the anterior abdominal wall and covers the blad* der, it attains its maximum ; in the detached folds of the mesentery, in the costal pleura, and in the so-called suspensory ligaments of the liver, it is still very prominent ; but on the posterior wall of the belly, and in the serous membranes where they cover many of the viscera, such as the heart, brain, lungs, liver, &c., it is almost completely deficient.\nOn the lungs, the necessity of its presence is probably superseded by the large quantity, both of the texture and of the property, which is inherent in these organs themselves : the remaining viscera are all organs of a size which is either little variable, or of uniform variety.\nIn the areolar tissue beneath the spinal and cerebral arachnoid, another modification occurs. Between the vascular pia mater, which closely envelopes the nervous centre, descending into its sinuosities of surface, and the visceral layer of the arachnoid, a considerable interval exists, in which the meshes of this tissue are exceedingly long and lax ; while, in many parts, the distance between them is so much increased as to form cavities, which have received the name of\u201c the subarachnoid spaces.\u201d They are filled with the fluid of the same name ; and by its presence the visceral and parietal layers of the serous membrane are maintained in contact, pressure generally becomes equalised, and large portions of the nervous centre hang suspended in fluid. The chief interruption to this arrangement obtains at the summit of the cerebral convolutions, where the arachnoid and pia mater are strongly adherent to each other : but the more minute description of these spaces or cavities belongs to the special anatomy of these membranes.\nThe fat cells which are so often deposited in the intervals of areolar tissue frequently occupy its meshes in the serous membranes. In most of these instances, however, it would be more correct to regard the subserous or connecting areolar tissue as the seat of the deposit, than that more condensed portion of it, to which an artificial separation would limit the term \u201c serous membrane.\u201d It is plentifully found in connection with both layers of the peritoneum, while it is comparatively absent from the arachnoid. In the case of the other serous membranes, the parietal layer is that which is most liable to its presence ; indeed, on the lungs, it appears to be completely and invariably absent. This latter circumstance has been ascribed to a supposed local antagonism of respiration to the deposit, analogous to that which is known to be exerted by this process generally. But this supposition seems quite untenable, since the lungs themselves are not nourished by the blood which it is their function to depurate, but by the ordinary arterial fluid, which exhibits the usual changes in the bronchial veins ; and one can hardly imagine respiration to exert an influence on the tissue, apart from, or greater than that which it exerts on its blood. Here, as elsewhere, the necessities of movement seem to be the circumstances which chiefly regulate the locality of the deposit : excessive mobility, as in the scrotum, penis, and eyelids, seeming to contraindicate the formation of adipose tissue. The amount present in these membranes generally exhibits a direct relation with that which is contained in the whole body.\nThe vessels-of the serous membranes ramify in their areolar tissue, and by their numerous anastomoses with each other constitute a","page":524},{"file":"p0525.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t525\nplexiform arrangement, which occupies, for the most part, a plane parallel to the surface of the membrane. Lymphatics in considerable numbers exist in the same situation.\nNerves.\u2014 Little is known of the manner in which these tissues generally are supplied with nerves. In the case of most of them, anatomy sufficiently shows that the amount of nervous tissue which they receive for distribution is but small ; and at present, even the aid of the microscope does not seem materially to affect this statement. The observations of Purkinje*. and more recently of Volkmann -j- and RaineyJ, however, agree in verifying the existence of a large number of nerves in connection with the cerebral and spinal arachnoid. They appear not to communicate with the roots of the spinal nerves, but to pertain exclusively to the sympathetic system ; and they branch and form plexuses in the areolar tissue beneath the arachnoid. But how far they are related to this membrane, or the serous membranes generally, or whether they belong more to the pia mater and other subjacent textures, seems at present incompletely determined, and is a question which will require an extended comparison with the other serous tissues.\nThe very painful nature of the diseases of these membranes is singularly contrasted with the slight amount of sensation of which they are capable in a state of health. It is probable that, as in the bowels, bones, and some other tissues, this contrast mainly depends on the minutiae of the anatomical arrangements of the nerves relatively to the tissue. In the serous membrane, this may perhaps receive some explanation when we call to mind that almost every morbid change to which they are liable has the immediate effect of converting a smooth, moist, and plane surface into one the nature and disposition of which implies a vast amount of friction, and the abnormal character of which draws this important distinction between it and other normal surfaces which rub with far more force : viz. that no provision has been made to guard against it. And if the arrangement of the nerves, whatever be its other features, allots to them as great a proximity to the surface as is granted to the vessels, it seems tolerably obvious, that any such friction would, in reality, amount to a serious injury of these delicate nervous filaments, and would be quite sufficient to account for the intense pain experienced.\nIn addition to the preceding tissues included in the ordinary enumeration of the serous membranes, there are other parts of the body which present structures so closely resembling these, as to render it perhaps doubtful whether this title can justifiably be withheld from them. The ventricles of the brain are lined by a membrane which exhibits the\n* M\u00fcller\u2019s -Archiv. 1845.\nf Wagner\u2019s Handw\u00f6rterbuch der Physiologie, artikel \u201c Nervenphysiologie.\u201d\nX Medico-Chirurgical Transactions for the year 1845.\ncharacteristic smooth and shining appearance of the serous tissues ; the posterior surface of the cornea is occupied by a similar layer ; and, according to Henle, there are considerable grounds for conjecturing the existence of some such structure on the inner surface of the membranous labyrinth and semicircular canals. But without here entering into the question of a possible transition of mucous into serous membranes being represented by these tissues, it will be sufficient to point out that while the ventricular and corneal membranes present a stratum of epithelial cells analogous to those described above, they are almost or entirely deficient in the important element of areolar tissue, \u2014 and that this constitutes a difference according to which the line of distinction is drawn, excluding them from the serous membranes. The epithelium which lines the general surface of the cerebral ventricles consists of flattened polygonal cells which are covered with cili\u00e6 ; but where it passes over the choroid plexus, it varies so considerably from this description as to merit a special notice.\nThe choroid plexus occupies the descending cornua of the lateral ventricles, and forms the margins of the velum interposition, the intimate structure of which it resembles in many respects. It consists chiefly of an interlacement of capillaries and capillary arteries. The former are of large size and great tortuosity ; and, in this last respect, they are similar to those of the synovial membrane already described. A little areolar tissue surrounds and supports the vessels, and a stratum of cells covers the surface of the plexus. Besides these structures, a large number of nerves have been described by Mr. Rainey as ramifying beneath the cells, but Purkinje and other observers deny the existence of nerves in this situation. Concerning the shapes of the cells which cover the plexus, similar differences of opinion and description obtain ; Henle*,Valentin f, and other high authorities speak of them as being in general polygonal, but somewhat flattened and curved where they cover the fringes of the plexus ; while, on the other hand, Mr. Rainey attributes to them a spherical shape and faintly granular contents. The following are their appearances as noted by the writer of this article.\nAt the margins of the fringes are seen many long and tortuous capillaries, the general course of which is parallel to the border of the plexus, and interrupted by few anastomoses. No basement membrane can be detected interposed between these vessels and the cells. The cells themselves are of a spherical shape, and of the very large size represented in the sketch (fig. 404.), many of them being one five-hundredth of an inch in diameter, a magnitude rarely paralleled by any cells but those of the adipose tissue : they contain a tolerably large nucleus in contact with their inner surface. Where exposed to the slightest pressure, they take a polygonal shape, but I\n* Allgemeine Anatomie, S. 228.\nf Wagner\u2019s Handw\u00f6rterbuch, artikel \u201c Gewebe.\u201d","page":525},{"file":"p0526.txt","language":"en","ocr_en":"526\nSEROUS AND SYNOVIAL MEMBRANES.\nhave never seen such an appearance except under these circumstances ; and at the edge of the fringe, which is usually more or less shielded from pressure by the prominence of the neighbouring surface receiving the weight of the upper lamina of glass, this perfect glo-bularity is readily verified. The cell-wall is extremely delicate and thin ; its contents are\nFig. 404.\n\u00a9\u00ae@\nCells of the Choroid Plexus. From the adult Cat-\nThe upper figure represents their arrangement in sit\u00fb ; in the lower, a, nuclei of ruptured cells ; b, cells detached. (Magnified 320 diameters.')\nfluid, and usually nearly transparent, and of a refractility not much different from that of water. So great is the delicacy of the membrane, and so little aid to observation is given by its colour or refractility, that at first it requires careful scrutiny before its presence is verified ; and its recognition is often retarded by the excess of light which the modern achromatic condenser affords. From this, which is the ordinary size, they pass by few gradations to a plentiful blastema, which fills up the interstices, and more or less completes the covering of the vessels. On tearing up such a fringe, most of these cells disappear, and their collapsed membranous walls may be found here and there, flattened and folded upon themselves, or burst at one extremity, and giving vent at the rupture to a faintly granular mass and their nucleus. The nuclei found in multitudes in such a specimen are round and pale, and contain granular matter and a single small bright yellow nucleolus ; or, rarely, there are two such spots. Many of these free nuclei exhibit a flattened or truncated surface, which indicates the extremity previously seated on the inner surface of the cell.\nWhatever may be the import of this peculiar structure, it is interesting to observe how closely, both in the arrangement of the vessels and the structure of the cell-covering, it resembles the synovial fringes previously described. The view of Mr. Rainey, that these spherical cells are nerve vesicles, seems to rest at present on the very insufficient basis of a slight external resemblance. But it appears\n? difficult to infer such complicated functions as are sustained by the nervous matter from such simple physical properties as sphericity, faint granularity, and the like, unaided by other structural analogies.\nDevelopment of serous membranes. \u2014 The steps of this process are little known, a circumstance which seems partly to depend on the extreme readiness with which it occurs, partly on the comparative simplicity of its nature : the cell being retained as the permanent form of the tissue, the mere apposition of a number of these in connection with a surface of areolar tissue is all that is required to complete the visible phenomena of its development.\nIn the animal kingdom, serous membranes are almost invariably present. They mostly appear in immediate connection with some higher development of the several viscera around which they are grouped. In this manner, first the peritoneum, and next the pericardium and arachnoid, appear. The first indication of the pericardium is in the mol-lusca, and its appearance seems to be immediately preceded by a mechanical provision of a very different kind, although perhaps of similar import : the heart is suspended in the centre of a muscular cord, which is attached by its two extremities, and thus fixes the viscus and steadies its movements. The peritoneum and pleurae are united in one in the reptiles ; afterwards, the latter membranes are shut off by the formation of a diaphragm. The tunica vaginalis is absent in those animals, in whom the testicles occupy a position within the belly.\nGenerally, there is the same obvious relation of their presence to mechanical uses which is seen in the human subject. But the ciliated serous membranes of many reptiles, and the urinating pericardium of cephalopods, offer, at present, such great and inexplicable differences from the human serous membranes, that one might almost doubt, especially in the latter of these instances, how far textures contrasted by such manifest differences of structure, and probably of function, can justifiably be called by the same name.\nIn the human foetus, their development is also little understood. This period of life, however, adds the amnion to the list of serous membranes, the structure of which it closely resembles. Its cavity is occupied by a saline and albuminous fluid in large quantity. It is subject to fluctuations in amount, and one or two analyses appear to show that the proportion of albumen which it contains is considerably diminished in advanced pregnancy.\nDevelopment by friction. \u2014 Besides these two forms, the development of some of these structures is witnessed in another condition, perhaps more peculiar than either; viz., in answer to the application of mechanical force. The subcutaneous bursae which are ordinariljr found over some of the various prominences of bone indicate the nature of their relation to these localities by their reproduction after","page":526},{"file":"p0527.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t527\nexcision ; while in other situations of the same kind, but in which they are not usually present, the application of long-continued pressure and friction gives rise to their production. If we add to these phenomena the development of diarthrodial false joints, it will appear that a certain amount of pressure is capable of determining the formation of a cavity, and the growth of a cell-covered membrane, which secretes a synovial fluid ; and that, exerted in a higher degree upon the more resisting bones, it clothes their extremities with a substance which presents all the appearances of cartilage. The presence of blood plasma is no doubt a necessary condition of both processes, but in neither are the subsequent minute changes known. In the case of the areolar tissue which is converted into a bursa, we may indeed infer, that mechanical violence exerted upon it would produce an increase of vascularity or an active congestion ; but we can scarcely conjecture how this alone should result in an increased vital activity, in the removal of some of the partitions of its net-work, the compression of others, the formation of a cavity, and the regular cell-covering of its inner surface.\nBut while the production of this structure in answer to pressure is exceedingly interesting, and offers a remarkable analogy to its general development in the foetus and animal kingdom, there is perhaps a danger of our exaggerating the resemblance, and becoming too mechanical in our views. On closer consideration, their ordinary and extraordinary formation will be found to exhibit a difference, which may teach us caution in our conclusions as to the method in which mechanical force acts. It is this : that while, in the latter case, their development appears to provide for a want already experienced ; in the former instance,\u2014in the young embryo,\u2014 we may observe a very similar development occurring, which is a provision for a necessity that has never yet existed, and cannot therefore be the immediate cause.\nPhysiology of the serous and synovial membranes.\u2014 At present, the physiological import of the preceding minute structural details is so little recognised or understood, as to leave scarcely anything to be said under this division of the subject. But, in this respect, these textures present so close a parallel to many others in the human body, that to consider this imperfect knowledge as demanding a complete silence, would be to interpose an insuperable barrier to almost all conclusions on any physiological subject. In truth, the question of the abstract truth or falsity of physiological conjectures by no means involves the question of their usefulness ; and the difficulty of retaining mere details, the danger of considering them as essentially knowledge, the possibility of allowing a philosophic suspension of judgment to merge into slothfulness,\u2014 all these circumstances taken together perhaps claim that such anatomical minuti\u00e6 should at least be considered with a\nview to their explanation ; even while they demand that the various shades of probability possessed by these conjectural explanations should, as far as possible, receive their due estimation ; and that their adoption should never interrupt the collection of fresh facts.\nSome attempt has already been made to discriminate between the physical and vital properties of these membranes ; and the mechanical advantages conferred by some of the former were enumerated as constituting their most prominent use. Their secretory function has next to be considered, together with any relations which this process may possibly bear to the organism generally, as the further use of these structures.\nA most important feature, and one which belongs to all these membranes, is their peculiar arrangement. The general statement, that they are so disposed as to form shut sacs, has been already alluded to, and was at no late period considered their characteristic definition. But as mere form could scarcely be thought of such essential importance, various attempts have been made to explain this morphological character, by referring it to some other term, which should either express a real cause, or should approximate to this by enunciating some physiological purpose itself implying the fact. Many of these, however, such as its being the result of the universal presence of epithelium, &c., are little more than re-statements of the fact in another form. But to the exception of the female peritoneum, long known, must now be added (unless the definition of these structures be arbitrarily extended so as to include many varieties of cartilage) all the articular synovial membranes, and many of the bursae ; in which the interruption to the continuity of the membrane constitutes the phrase \u201c shut sac,\u201d an inaccurate expression as applied to them.\nIn short, all that the term really implies is, that there is no visible outlet by which the cavities these tissues form, or assist to form, can communicate with the exterior of the body. And even in the case of the apparent exception at the extremity of the Fallopian tube, it is exceedingly probable that the small size of the aperture of communication, the ciliated lining which it possesses, and the direction in which the current of ciliary motion sets, constitute it, in effect, a closure. The internal position of the serous membranes is followed by this important physiological consequence, that the contents of their cavities are never directly eliminated from the body ; but that such portions of the substance of the membranes, or of its separated products, as may become effete in the course of the vital changes, can only be discharged from the system after a previous reception into the general mass of the circulating fluid. This fact at once establishes a broad line of distinction between these tissues and the mucous membranes, or true glands ; while at the same time it tends to prove that their secretion, whatever it may be, possesses little of the deleterious quality, or excretory","page":527},{"file":"p0528.txt","language":"en","ocr_en":"528\nSEROUS AND SYNOVIAL MEMBRANES.\ncomposition, which marks many of the products of the mucous system.\nContrast of serous and synovial membranes. \u2014 The shape of the cell of serous membrane may afford some indications of its history. In flatness, it occupies a position about midway between the squamous outer epithelial particles of the skin, and the columnar intestinal cells. The conditions which lead to the excessive horizontal extension of the former appear to be, a vertical pressure acting upon them during their growth, and aided by an evaporation which diminishes the cell-contents, themselves originally small in quantity. On the other hand, the immediate cause of the prismatic or columnar shape is, no doubt, a horizontal pressure mutually exerted by the growing cells themselves. This pressure appears generally to limit their diameter to that of the contained nucleus ; a smaller diameter, which implies the existence of a greater number of cells in a given space. Their longitudinal extension similarly involves a greater amount of contents ; so that, on the whole, this might be termed the highest form of cell-growth, the development and filling of a large number of cells simultaneously.* Comparing the serous epithelium with these two extremes, we may recognise in its flattened shape the effect of vertical pressure on a cell containing but little in its cavity ; while the comparatively small number of cells in a given space, and the oneness of the layer, are further indications of the moderate activity of the cell-growth. The uniform size and polygonal shape of the constituent cells, together with their great mutual adhesion by their edges, or in the horizontal plane; \u2014 these are circumstances which seem to point to the simultaneous development of the whole layer, and to the previous causes of flatness determining its growth almost exclusively in this direction.\nThe little aid afforded by the composition of these cells is derived from observations which are chiefly of a negative kind : since they show that the cells do not offer any considerable chemical differences from the liquor sanguinis, but consist chiefly of albuminous and fibrinous materials.\nThe nature of the serous secretion seems little understood. In health, the quantity of fluid present in the interior of the membranes is only sufficient to moisten their free surface ; while where its amount is enough for the purposes of analysis, the accompanying diseased conditions would prohibit our assuming its identity with the normal fluid, even if the supposition were not rendered untenable by the varying composition of the fluids themselves. But, on the whole, the very small quantity of fluid naturally present, its comparatively limpid consistence and transparent appearance, together with the absence of the cell-form in which secretions are involved, probably refer it immediately to the simple\n* For some further remarks on the subject of cell-growth, the reader is referred to a future article, \u201cStomach and Intestinal Canal.\u201d\nphysical process of transudation ; a process which is present everywhere in the body, but is favoured by the thin parietes of these structures, while their position prevents the removal of the fluid by evaporation.\nBut the fluid yielded by this supposed process appears to be chiefly aqueous ; and the question therefore readily suggests itself, whether any mere transudation could filter off the dissolved constituents from a perfect solution, such as the liquor sanguinis is known to be; and whether the elective affinities of the tissue itself may not constitute the main agents of the process, by retaining certain materials, and allowing others to obey this physical law. Valentin * mentions some experiments in which dried serous membrane was used as the filter, and albumen, so far suspended in water as to constitute a homogeneous fluid under the microscope, was passed through it. The result was, that it retained a thicker portion, while only a thinner or more dilute part passed through. But saline solutions transuded entire, and perhaps the doubtful state of solution of the organic constituent will not permit much reliance to be placed on these experiments. In connection with this subject, Mr. Paget f has pointed out that the different serous membranes seem to effect this \u201c filtration \u201d with different degrees of fineness. And, possibly, the diminution of albumen noticed in the liquor amnii of advanced pregnancy may be ascribed to a similar subtraction from this fluid by the serous membrane in the cavity of which it is situated. The share which the cells as such take in this process can scarcely be conjectured ; but that their disposition in such a form is not absolutely essential to the fluid, is shown by its occurrence in the areolar tissue, where such a stratum is absent. And while we know next to nothing of the process itself, and have no name by which it may be exclusively indicated, it is important to recollect that the words used above, \u201c elective affinity,\u201d \u201c subtraction,\u201d \u201c filtration,\u201d are probably alike inaccurate ; that the first seems to imply chemical combination, the second represents the subtracted materials as too passive, the third is the name of a physical process by which solid objects are left behind after the removal, by capillary attraction, of the fluid in which they were suspended. The processes to which it seems most analogous, and to which it may best be compared, are those curions varieties of heterogeneous adhesion existing between bodies of different cohesive forms, of which the action of charcoal or platinum upon certain gases are familiar instances\nThe period of duration of the cell-growth, and the manner of its renewal, can only be conjectured. But from the constant absence of shed epithelium from the interior of the membrane, and the uniform shape and mutual\n* Lehrbuch der Physiologie des Menschen, Band 1., S. 601.\nf Report on the Progress of Human Anatomy (Brit, and For. Review, year 1843-4, p. 10.)","page":528},{"file":"p0529.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\nadhesion of the cells, one might imagine that the stratum ordinarily lasts a considerable period without experiencing any desquamation or substitution of new cells. And although the ease with which a layer of cells is stripped off by slight force might at first sight seem opposed to such a notion of their durability, yet it is tolerably certain that the mechanical relations of the cells are so adjusted as to allow the free gliding movements of their moist, smooth surface with perfect impunity. While, on the other hand, where the presence of the tissue seems to fulfil its main object, a mechanical one, and where the flattened epithelium does not include the elements of a secretion in any quantity, and consequently would hardly fulfil any secretory purpose by its occasional or exceptional separation ; to what purpose should it be ever shed at all ? The serous membrane exhibits one layer of solid cells, all of which are related by one (the nucleated) surface with the neighbouring vascular supplies, while they present their op-posite surface to receive a slight friction ; and it does seem possible that the effete materials may be removed, the losses of friction made up, and, in a word, the gradual exchange which constitutes the nutrition of a tissue accomplished, without the disruption of the old cell and the -substitution of an entire fresh one. The cell-form does not necessarily imply evanescence, and the centre of attraction which it constitutes can hardly be supposed unfitted for the processes of ordinary nutrition, because it sometimes collects materials which imply its destruction, or is thrust away from the sources of nourishment by its fellow vesicles. And if it should be asked, \u201c Why is the serous membrane constituted of cells, if the ordinary form of nutrition would suffice?\u201d it might be pointed out that, although the form of nutrition be the same, its pace may and probably does attain a greater rapidity in cells than in the more permanent textures, and that by their instrumentality the rubbing surfaces ate everywhere separated by an appreciable interval from the delicate capillaries, a condition that could scarcely obtain in areolar or ligamentous tissue, however it were disposed ; and that in addition to this, cells offer the mechanical advantage of forming a smooth tesselated pavement, while they possess the physiological merit of readily repairing the accidents to which this tissue seems comparatively more liable than others.\nThe synovial membranes seem to differ from the serous membranes in most of these respects. The cells which cover the general surface of the membrane are more spherical, less uniform in size, and less accurately tesselated ; while on the highly vascular fringes, the large, globular, and distended epithelia, with their plentiful blastema, strengthen the indications of active secretion thus afforded. The presence of synovia in considerable quantity, and the recognition of the ordinary secretory process, by the detection in it of relics of cells, chiefly nuclei, form another ground of distinction. This secretion of viscid fluid\n52 9\nappears tobe indirectly referrible to the greater pressure exerted on these surfaces, and the consequent necessity of a further protection against friction ; while it is no doubt immediately the result of the separation of this active cell-growth, alone, or accompanied by fluid derived from the vessels. The bursting of the distended and delicate cell is probably the agent of the separation, and may be due solely to a distention beyond the physical power of resistance which its wall possesses.\nThe resistance of the cells on the general or capsular part of the synovial surface, and the irregular and isolated manner in which force detaches them, have been previously noticed, and contrasted with the facility of removing the whole layer of serous cells. They seem to denote, not only a mechanical adaptation to greater friction, but perhaps a corresponding independency of the cells, which possibly form a continuous and active growth, scarcely any two portions of which are exactly of the same age.\nAnd not only is the secretory activity of these membranes much greater, but there is every reason to suppose their absorptive functions are still more increased. Assuming*, from the preceding appearances of active cell-growth, that a greater quantity of fluid is secreted by them into the cavity of the joint than the amount of serum which finds its way into the interior of the serous membranes ; \u2014 since only a tolerably uniform and small quantity is discovered to be present there,\u2014 it will follow, that the rapidity of its removal has corresponded with that of its introduction : and as this removal cannot be attributed to-any other cause than that of absorption, we must therefore regard its increase as parallel with the increase of secretion.\nBut there is another circumstance which renders it likely that the former of these two processes is even disproportionally greater. However carefully the surfaces of diarthrodial cartilage may be lubricated by the synovial fluid, a very slight knowledge of mechanics would inform us, that some friction of these must of necessity obtain ; and that from the conditions of its density, homogeneous nature* &c., it is probable that the amount of this is, though diminished, yet by no means inconsiderable. So also, from the structure of this substance, it is physiologically probable that-its tissue grows towards this surface, and that the arrival of any one particular portion at this point is, mediately or immediately, the cause of the termination of its existence. While the anatomy of this free edge abundantly confirms the fact of such an attrition: vertical sections show an irregular border, from which some cells are seen slightly projecting, while others appear (as in flgA02) ground down to its level.\nWhatever be the amount of cartilage which is thus rubbed off' and set free in the cavity of the articulation, or whatever may be the cohesive form which it assumes, the thick and solid cartilaginous lamina which is interposed between this \u201cdebris\u201d and the\nM M\nVOL. IV.","page":529},{"file":"p0530.txt","language":"en","ocr_en":"530\nSEROUS AND SYNOVIAL MEMBRANES.\nvessels at the osseous surface (the vessels to which in the first instance the formation of the tissue was due) seems to constitute an effectual barrier to the performance of its absorption by them. And since the process no doubt occurs, the only remaining vascular surface, or that of the synovial membrane, is clearly indicated as the agent by which it is effected.\nHence, the synovial membrane possesses, so to speak, a double absorptive function : one, which is essentially its own, counterbalancing the active progress of secretion, of which it is the seat ; another, which is, as it were, delegated to it by the cartilage, and is the result of the physical incapacity of the latter tissue.\nAnd in a sketch of the morbid anatomy of these structures which occupies the subsequent part of this article, it will be seen that the mutual dependence thus supposed to exist between the articular cartilage and synovial membrane in health, finds, in all probability, a close parallel in some forms of disease. The chief difference noticeable here is, that the preliminary breaking up of structure which appears to be chiefly physical or attritional in the normal cartilage, is a vital process which is inherent to the diseased texture.\nThe subcutaneous and subtendinous burs\u0153 present a similar fluid, which is usually in much smaller quantity. They seem, in most of the preceding respects, placed midway between the serous and synovial membranes ; but many of the preceding remarks, mutatis mutandis, are applicable to them.\nThe close resemblance of the choroid plexus to the synovial fringes was pointed out in speaking of the former structure : but it is obviously almost impossible to conjecture a similar mechanical import of its secretion ; nor, indeed, have we any reason for asserting the separate existence of a fluid secreted by it.\nIn respect of their internal situation, all the preceding tissues resemble that recondite class of structures, the glands without ducts; and their similarity of form has also a physiological parallel; \u2014 viz. that all their constituents are returned into the blood, either unchanged in their composition, or elaborated, or effete. They differ from them, however, both in the greater perfection or maturity of their cell-form, and in the lesser activity of their secerning power.\nIn the degree, and perhaps in the nature, of this resemblance, some distinctions may be drawn. Thus, the serous membranes, in the possession of a solid attenuated epithelium, and in the probable absence of a secretion, are at the lowest or most distant extremity of the scale ; raised very little above areolar tissue. The synovial membrane, with its much more active cell-growth, and its fluid secretion, comes somewhat nearer; albeit, the secretion seems mainly developed in answer to the mechanical requirement of a lubricating fluid. Still, the possibility of a less\nphysical function of both these tissues must not be lost sight of. In the choroid plexus, the approximation is made yet more close by the negation of this mechanical import; and we are left in complete doubt, whether it is a provision for quantitative or qualitative fluctuations in the blood which supplies it ; whether, in either of these cases, the cell-growth operates a chemical change or elaboration on the materials submitted to its action ; or, finally, whether it returns these to the circulation, or surrenders them at once to the neighbouring nervous tissues.\nMorbid Anatomy of Serous and Synovial Membranes. \u2014 The following sketch of the diseased appearances of these tissues is necessarily limited to their more general features. At present, it is scarcely possible to discriminate between the very analogous pathological conditions of the two classes of serous and synovial membrane ; although it is probable that an advance of knowledge will at no distant date enable us to do so. And even where the distinctions of appearances are sufficiently palpable, our ignorance of their general nature allows few inferences to be drawn from these varieties.\nThus, the remarkable immunity from mechanically-produced effusions which the synovial membranes enjoy is little understood, although one may perhaps doubt whether it is quite so complete as it is generally supposed to be. The only conjecture that seems at all probable is, that the nature and activity of the cell-growth which covers their surface may have some relation to the difficulty with which such fluids transude. So, also, the comparative infrequency of adhesion in their inflammations is, at present, a vague fact, the cause of which is unknown; \u2014 it may either be referred to an explanation similar to the preceding, or may, as Professors Todd and Bowman suggest*, depend upon the presence of a viscid secretion in their interior.\nSerous or dropsical effusions. \u2014 One of the most frequent of the morbid appearances seen in these tissues is the presence of a serum-like fluid in their cavity. It occurs in a very large number of deaths from various diseases. In most instances, however, the serous membrane only shares in a dropsy which is common to other structures, and especially affects the areolar tissue. Thus, for instance, where death has resulted from some mediate or immediate obstruction to the passage of blood through the right cavities of the heart, and has been preceded for some time by general anasarca, it is usual to find a considerable quantity of fluid occupying the pleura, peritoneum, and other serous membranes. In other diseases, as in cirrhosis, the serous effusion is not only a more direct result of a greater venous obstruction, but it also assumes a higher import than in the previous instance, and becomes both of earlier occurrence in the history of the dis-\n* Physiological Anatomy and Physiology of Man, vol. i. p. 131.","page":530},{"file":"p0531.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\n531\norder, and of weightier influence upon its termination. Here, an accompanying dropsy of the areolar tissue is less frequent and prominent, but it still generally follows at a certain stage of duration and intensity : it is usually ascribed to the pressure of the distended belly acting upon the vena cava, and producing a secondary dropsy from the branches of the systemic circulation which join that vein.\nIn another class of cases, the serous effusion is still common to the areolar tissue and the serous membranes, but it arises from a different cause ; one which is no longer a mechanical impediment, but a chemical alteration. The dropsy of chlorosis is a good example of this species of effusion, and to it may probably be also referred that seen in the latter stage of phthisis and other exhausting disorders. Analysis shows, that in these an\u00e6mi\u00e6 the blood is rendered much poorer by the loss of a considerable proportion of its albumen, and the serum of the thus diluted fluid possesses a greater tendency to transude the membranous walls of the vessels, and pervades the surrounding structures in an undue quantity. Below a certain percentage of albumen, Andral affirms the occurrence of dropsy to be tolerably constant.\nTo these two classes may be added a third, in which serum is found in these structures without any sign or symptom of its presence having been detected during life. These cases are so numerous, that, even after subtracting a considerable number as possibly due to neglect or difficulty of recognition during life, a large number still remain, in which the effusion may be fairly presumed to have taken place after death. And in many instances, they are not only affected by gravitation, but, like the very analogous condition of the areolar tissue, their occurrence seems to be favoured by it. Yet, as such appearances are absent from a large majority of post-mortem inspections, it will follow, that the effusion of this fluid is to be ascribed, at least in part, to some conditions other than mere gravity. These are probably similar to the circumstances which conduce to the production of the preceding class of effusions, a deficiency of the albuminous constituent in the blood, or, with lesser likelihood, the condition of the walls of the containing vessels themselves. They thus appear to be due to both a mechanical and chemical affection of the blood, and so seem to offer an union of the two causes to which the preceding classes have been severally ascribed.\nMany of the serous fluids which are found in the ventricles of the brain and beneath its arachnoid membrane, offer sufficient distinctions in their nature and causes to merit recognition as a separate variety. They are alike independent of phj'sical obstruction of the vessels, or of a qualitative alteration of their contents ; while their quantity, which is frequently a considerable one, and the corresponding diminution of the size of the brain, together clearly indicate that they are not\ndue to mere post-mortem phenomena. But while, on the one hand, they are unattended by these, the ordinary causes of such effusions, and are devoid of all symptoms which would indicate them as in themselves morbid ; so, on the other, they are not present in the healthy subject. Hence we may deduce, first, that they are related to some abnormal condition ; and secondly, that this relation is not an immediate one. This may be confirmed by considering that the organ bathed by these fluids is one which, from its physical and physiological properties, its soft consistence and important functions, is both peculiarly susceptible of disturbance from pressure, and ready to give signs of such disturbance ; so that the absence of these indications betokens a nicety of adaptation of the fluid to the cranium and its contents which is hardly to be explained in any other' way than by supposing that this adaptation is itself the object which the presence of the serum fulfils, or that the want of it is the condition which necessitates the effusion, if indeed it does not more immediately give rise to it.\nIn the cerebro-spinal fluid itself, we are presented with a more normal counterpart of this scarcely morbid effusion ; since a fluid of similar constitution, in lesser quantity, is here a constant phenomenon. In the loose and vascular areolar tissue between the arachnoid and the spinal cord, this perpetual dropsy is the natural condition of the part ; and is perhaps due to the greater mobility enjoyed by the vertebral column where it surrounds these parts of the nervous centre, a freedom of movement which requires that they, in their turn, should be more carefully protected from external violence.\nPhysical and chemical properties. \u2014 The appearances of the fluid found in the circumstances above mentioned are tolerably uniform, and the few variations that occur are chiefly of an accidental nature. It is usually a limpid, colourless, and. transparent fluid, of a faintly alkaline reaction ; and, in a state of purity, it offers no trace of organization, either to the naked eye or the microscope. In its consistence, however, it is susceptible of great differences. It varies from the limpidity of water to the viscidity of synovia ; and when containing very much albumen, is sometimes even thicker and more tenacious than this liquid. Its colour is very frequently and greatly affected by admixture with blood, bile, and other matters; or by the partial precipitation of its albumen ; or, more rarely, by the solidification or crystallisation of fatty constituents. Many of these causes also affect its transparency, giving it more or less opacity, as well as colour. Its alkalinity is less liable to variation ; but occasionally it is neutral, and very rarely acid. Its unorganized character is only interfered with by accidental impurities similar to those above noticed.\nThe chemical composition of these fluids is much more variable; indeed it is very probable that scarcely any two of them are M HI 2","page":531},{"file":"p0532.txt","language":"en","ocr_en":"532\tSEROUS AND SYNOVIAL MEMBRANES.\nexactly alike in this respect. The following table exhibits four analyses, contrasted with that of the serum of the blood : \u2014\n\tSerum of Blood.\tPhthi- sis.*\tAscites .f\tAscites.\tAscites.\nWater-\t905\t988\t988\t956\t704\nAlbumen\t78\t3\t0-9\t29\t290\nExtractive -\t4-2\t\t\t9\t2\nFat -\t3-8\tr 9\t10\t7\t\nSalts -\t9\tJ\t\t8\t4\n\t1000\t1000\t998-9\t1009\t1000\nThe difference in the amount of albumen which these analyses exhibit is very striking ; and the large quantity present in the latter is especially remarkable as offering nearly four times the quantity which is present in the serum of the blood. The anomaly of an unorganized liquid, derived from the blood, possessing more of this important constituent than the parent fluid, has been attributed by V\u00f6gel to a reabsorption of the watery parts subsequently to the effusion. The varying methods of analysing these fluids leave less room to remark quantitative differences of their other constituents. The quantity of salts seems, however, pretty constant ; although the following analysis J exhibits a singular increase in one of the most common saline ingredients. It was taken from the dropsical belly of a woman aged 40, and the urine is stated to have contained about 6 parts in the 1000 of the same salt.\nWater ------ 950\nExtractive, with, traces of albumen - 5-97 Fat\t-84\nAlmost pure chloride of sodium\t44\n1000-81\nThe small number of analyses hitherto made, and the incompleteness of the pathological notice with which they are usually accompanied, render it at present too early to arrange the composition of these fluids in any real connexion with the various morbid states which have regulated their production. But the possible cause of an excessive preponderance of albumen has been already alluded to, and on the whole it seems likely that the cases where this substance is of a Jess remarkable, but still a considerable amount, belong chiefly to the category of dropsy from mechanical obstruction ; while the dropsies of an\u00e6mi\u00e6, post-mortem transudation, and the like, seem to be characterised by the possession of a very small quantity of albumen : thus the second analysis in the table exhibits only three parts in the thousand ;\n* Reduced from an analysis by Karl Frua. Heller\u2019s Archiv., 1845, S. 363. The fluid was found in the abdominal cavity.\n\u2022f An analysis by V\u00f6gel, from whose \u201c Pathologie \u201d the remaining analyses by von Bibra, Dublanc, and Lecanu, are quoted at second-hand.\nX Heller\u2019s Archiv f\u00fcr Phys, und Path. Chemie, 1844, S. 47.\nand two or three others are given by the same author, which have a very similar composition. In the serous fluids of the cerebral ventricles, the quantity of albumen appears still smaller, as is exemplified in the following analysis by Berzelius.*\nWater ------\t988'3\nChloride of sodium and potassium -\t7-09\nAlbumen -\t-\t-\t-\t1-66\nLactate of soda, with alcohol extract -\t2-32\nSoda ------\t-28\nExtractive, with traces of phosphates . '35\n1000-00\nIn respect of their diminished quantity of albumen, it is difficult to avoid noticing their approximation to the characters of the cerebrospinal fluid, the vitreous humor, and other healthy effusions.\nThe question that next suggests itself is, \u201c What relations do these fluids bear to the serous membranes ?\u201d From a comparison of the analyses quoted above, it is sufficiently obvious that amid multiform phases of composition all these fluids preserve a close resemblance to the serum of the blood ; a feature which sufficiently testifies to their origin and import, and which refers their production to the conditions of the blood, and their consideration to the pathology of this fluid, rather than to the serous membranes in contact with which they are found. And the bearing of this evidence is corroborated by several other facts. In a vast majority of cases, as above mentioned, their occurrence may be directly traced to blood disorders ; either a qualitative affection of this fluid, or a mechanical distention of its Containing vessels,\u2014 a mutual dependence which tends still more to allot them to the blood rather than to the serous membranes. Again, instead of their presenting the cellular form, in which the elements of secretion, morbid as well as healthy, are usually involved, and which they might be expected to assume were they essentially the product of the cell-growing membrane, they are devoid of all appearances of such organization. While in place of being peculiar to these membranes, it is found that an identical effusion obtains in the areolar tissue ; a structure which is alike destitute of their membranous form and epithelial covering.\nInflammatory or fibrinous effusions. \u2014 A large number of the fluids which are found effused in the interior of the serous membranes offer characters which essentially distinguish them from the dropsical effusions above described. The first and most prominent differences are those presented by their appearance and chemical composition. In addition to the albumen and salts which form the main constituents of the serous effusions, they also offer a greater or lesser quantity of fibrine ; and as this substance retains its ordinary power of spontaneous coagulation, its presence is readily recognized by the eye.\n* Simon\u2019s Chemie, Band ii. \u00a7 581. The case is mentioned as \u201c Hydrocephalus.\u201d","page":532},{"file":"p0533.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t533\nTo these physical differences accede equally important pathological grounds of discrimination. The effusion of the fibrinous fluid is usually attended by more or fewer of those symptoms, the aggregate of which is known by the name of inflammation ; and in the few instances where these external indications are absent, the presence of the fluid is itself considered sufficient evidence of the previous occurrence of the inflammatory process ; while the mechanical causes, which often appear mediately or immediately to determine the occurrence of the simply albuminous effusion, seem to have no influence in the production of these phenomena. Lastly, the fibrinous effusion is distinguished by this important quality, that it is susceptible of organization, or capable of an apparent conversion into tissues, the structure of which closely approximates to that of some one or other of the normal and permanent textures of the human body.\nThe class of effusions characterised by the possession of the common properties of fibrinous composition, inflammatory origin, and susceptibility of organization, is a very large one, and includes a great variety of fluids. The extremes of these numerous gradations offer some contrast ; in one the symptoms of inflammation are well marked, and the effusion chiefly consists of matters which are plastic : ire. which pass rapidly from a fluid state, through that of an uniform pasty mass, into a solid form ; and which for the most part experience a rapid and complete organization, being converted either into pus or into some more permanent structure. In the other subdivision, the symptoms of inflammation are usually less marked, the fluid contains less fibrine, is less susceptible of organization, and not only remains chiefly fluid, but, in a large number of instances,- does not deposit any part of its contents in a solid form until subsequently to its removal from the living, body,, or after the death of the patient-\nIn the earliest stage of inflammation, and before effusion has yet occurred, the morbid appearances of the serous membranes are limited to an injection, or active congestion of their vessels. Most of these, it will be recollected, are arranged as a flattened plexus in the areolar tissue which forms so large a part of the membrane ; and the injection of this plexus, at first in isolated points, and afterwards in larger patches, gives to these parts of the free surface a heightened red colour, which is clearly visible through the thin and almost transparent layer of cells, alone intervening between the capillaries and the interior of the membrane. But although a superficial, patchy,- and well-marked redness, dependent on congestion of the minutest vessels, constitutes a tolerable presumption of the presence of inflammation, yet such a state can be so closely imitated by conditions which are not inflammatory, \u2014 such as a merely passive venous congestion, due to position of the body, mode of death, and a variety of other causes, \u2014 as to be, in a majority of cases, of little\nvalue as evidence of this process. And even in instances where the symptoms during life have rendered the existence of inflammation probable, an examination after death has often detected no such appearance ; whence it w ould seem that this vascularity is capable of disturbance or removal, either during the phenomena of death, or after that event has happened. And it is also to be noted, that the different serous structures seem liable to this appearance in a very different degree :\u2022 some, as the arachnoid, scarcely ever presenting any trace of such a suffusion ; while in others, as the pleura, it is much more frequent. So that, on the whole, it may be stated that neither does its presence affirm, nor its absence deny, the occurrence of inflammation ; still less, where present, is its amount to be considered any measure of the intensity of the process.\nAn alteration in the texture of the membrane itself is probably immediately subsequent to this injection in the order of time, and is generally seen in connection with it. Its surface, instead of the smooth and shining appearance which it ordinarily possesses, be-^ comes dull and dim, while it is dry and almost rough to the touch ; and- at\u00bb the same time the thin and transparent expanse of its texture acquires a milky opacity, and an increased thickness, which in the more delicate serous membranes is especially well marked. The former of these appearances probably indicates some affection of the epithelium, which clothes the free surface of the membrane ; but the latter is due to the commencement of effusion. This process begins where we should naturally expect it, viz. in the immediate neighbourhood of the vessels, or in the subserous and neighbouring areolar tissue in which they ramify ; and by the filling and distention of the meshes of this net-w*ork, it gradually communicates its own appearances to the surrounding tissue generally.\nThe next stage is constituted by the appearance of the products of inflammation on the inner or free surface of the membrane, or the effusion of a plastic fluid into their cavity.\nThis effusion is at first a clear transparent fluid, of a tolerably limpid consistence. It is true that we are rarely able to verify this transparency in the exsudation of the larger serous membranes ; but the condition of the blood plasma from which it is derived, and the similar appearance which is visible in the case of fluid effused into the inflamed anterior chamber of the eye, together leave no doubt of the fact.\nIn a space of time which is a very short one, this uniformly fluid state usually gives place to a greater or less opacity and solidification; and in this, the earliest stage in which the effusion is generally recognized, it offers the appearance of a milky semifluid substance, which either forms the whole of its mass, or is mixed with a variable quantity of serum, from which it has thus already begun to separate.\nThe composition of this effused fluid exhibits mm3","page":533},{"file":"p0534.txt","language":"en","ocr_en":"534;\tSEROUS AND SYNOVIAL MEMBRANES.\ngreat variety in different cases. The following table is an average of five analyses by Quevenne, Scherer, and V\u00f6gel, which is compared with the liquor sanguinis of healthy blood, as analysed by Lecanu. This important comparative method of regarding these fluids is due to V\u00f6gel, in whose valuable work these analyses are given at length.\nWater -\nFibrine -\nAlbumen\nExtractive\nFat\nSalts\nLiquor Sanguinis.\n-\t906\n3-4 77\n: 1}\nFibrinous Effusion. 934'936 \u2022984 51-88\n12-2\nThe composition of 1000'4\t1000-\nA comparison of the composition of this fluid with that of the serous effusion which was previously described, not only exhibits the addition of a new constituent, fibrine, but it shows the quantity erf albumen to be increased in an important degree ; it being, on the average, nearly trebled. Contrasting it with the normal liquor sanguinis, it is seen to possess a considerable proportion of its albumen and fibrine, although less than this fluid itself contains. And it is important to notice, that the former of these two constituents is not only present in larger quantity than the latter, as might be expected from its very different amount in the parent fluid, but in a much greater proportion of its respective quantity, i. e. that only two-sevenths of the fibrine of the liquor sanguinis appears in the inflammatory exsudation, while five-sevenths of its albumen is present. And in all probability, were the diseased liquor sanguinis of the same subjects the object of comparison, its increased quantity of fibrine would render the disproportionately small transudation of this constituent a still smaller one. Although the number of analyses from which the average is taken will allow little stress to be laid upon these facts, yet they have seemed to deserve especial notice, as having some bearing upon a question which is of the greatest importance to pathology, and which cannot yet be considered as settled, viz. \u201c What is the relation of fibrine to the process of organization ?\u201d\nThe further progress of the exsudation arranges the plastic or fibrinous constituent as a more complete coagulum, which is in contact with the inner surface of the serous membrane. The colour of this portion of the exsudation is yellowish, or sometimes reddish from mixed blood ; its thickness varies from that of a scarcely perceptible deposit to one of half an inch or more in thickness. The uniformity with which it covers the interior of the membrane is also subject to great differences ; sometimes it is arranged as a stratum of tolerably equal thickness over the whole or a greater part of its extent, at others it is limited to the formation of raised points or patches which here and there stud its surface. These conditions apparently indicate a corresponding diffusion or limitation of the inflammation. In like manner, the state of\nsurface of this stratum is liable to great differences, being sometimes level and comparatively smooth, while in other instances it offers every conceivable degree of roughness, from a trifling irregularity of surface to those long, large, and shaggy processes which are so often seen in acute pericarditis, and which have been well compared to the villi of an ox\u2019s tongue. Considerable difference of opinion prevails as to the exact mode in which this curious state is produced : thus some imagine it to be the result of the mutual movements of the visceral and parietal layers of the membrane ; or that, in separating from each other, they draw out a thread of the viscid and coagulating paste, until it breaks, and thus leaves a projecting process attached to each of these surfaces. But the fact, that an elongation very similar to that of those processes is seen in solitary warty deposits on the valves of the heart, in situations where no such physical causes as this can be supposed to obtain, renders this explanation more than doubtful ; and, on the whole, the interpretation of V\u00f6gel seems much more probable, that they result from a want of uniformity of the effusion in the first instance forming small scattered patches of lymph, on and around which, as around foreign bodies, the subsequent continuous effusion tends to deposit itself.\nThe first layer of fibrine thus deposited on the inner surface of the membrane forms, if it is complete, a kind of sac, in which the more serous part of the exsudation is included. But this liquid part generally contains a considerable further portion of the fibrinous element ; and the resulting phenomena appear to depend in some measure on its amount. Thus, if the exsudation be almost wholly of plastic material, large irregular masses of fibrine are found in the cavity of the membrane ; the serous fluid being only in sufficient quantity to moisten these loose coagula. If the serum be superabundant, the fibrine may remain almost or entirely dissolved in it ; or may only be visible as a slight disturbance of its transparency, imparting to it a white colour, or forming a few scattered flakes which float hither and thither in the fluid. A medium between these two extremes is perhaps more common, in which the plastic element coagulates in a loose irregular kind of net-work, the meshes of which enclose the serum. And with this more general precipitation there is usually a special deposit upon the peripheric or oldest layer before mentioned, which imitates its irregular or shaggy form. But as this process of coagulation is often a very slow one, the extent of lamination is by no means limited to these two layers ; five, ten, or twenty thin strata often appearing to be laid down from the fluid, one after another. In all these cases, the denser and stronger layer, in contact with the surface of the serous membrane, is the original plasma, the first which was deposited, and the earliest to be organized. Rarely the completeness of this coagulation leaves the serous part entirely","page":534},{"file":"p0535.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t535\ndevoid of fibrine, and, in respect of composition, closely resembling some of the dropsical fluids previously described.\nOrganization of the effusion. \u2014 In some very few instances, in which the exsudation is only in a limited quantity, absorption occurs prior to the deposit of the fibrinous portion ;\u2022 but after this change has once occurred, and the fluid has been separated into a serous and solid portion, the former only is susceptible of removal, the latter or fibrinous constituent being either absolutely incapable of absorption, or, what is perhaps more probable, being removed so slowly as to be replaced by the organization of new tissues long before its withdrawal is completed. When the quantity of fibrine is small, organization is on the whole both less frequent and rapid. Still it may occur; and even where this substance is retained in solution, the fluid containing it is susceptible of this change.\nBut although the products of inflammation generally progress towards organization, yet the steps and results of this further development differ very widely from each other.\nIn the majority of these effusions, one of two processes occurs. In one*class of casesr the free surfaces of the membrane are glued together by the coagulable lymph effused upon them ; and this cementing substance is either itself converted into a permanent structure which obliterates the cavity, or it forms a nidus, or stroma in which the structure is developed. In another set of cases, the plasma experiences a rapid development into a number of cells, floating in a thin fluid. These are termed the adhesive and suppurative forms of inflammation respectively ; or sometimes, with perhaps less correctness, the \u201c terminations \u201d of this process.\nIn some instances-, however, a process similar to the first of these takes place independently of adhesion. Sometimes, the plastic layer on the inner aspect of a serous membrane experiences a transition into a structure which resembles areolar tissue, and presents an irregular or shaggy surface, like the fibrine for which it is substituted. In other instances, a thinner layer, with a more regular surface, is formed, and clothes the normal structure with a new serous or fibro-serous membrane, which can readily be peeled off from the subjacent tissue. This layer is rarely of uniform thickness, and when limited to small isolated patches forms the \u201cwhite spots\u201d which are so frequently seen in the pericardium.. In these instances, the effusion is evidently in very small amount, and probably consists almost wholly of the plastic materials of the blood, with very little accompanying serum.\nAnother class of cases may be mentioned here which, in respect of the absence of adhesion, are somewhat similar to this condition. They differ from it, however, in the fact of their presenting a large quantity of a serous or little fibrinated fluid, and in the very slow organization of their solid matter, which, in some instances, advances so little in a con-\nsiderable lapse of time, that we might almost doubt the occurrence of any further deve-lopement. In these instances, the small amount of plastic material present is irregularly deposited here and there in the shape of small granules of fibrine which are scattered over the surface of the serous membrane. This condition frequently occurs in the peritoneum, and has been called \u201c tubercular peritonitis.\u201d It offers,, however, such wide distinctions from the really tuberculous inflammation, that it is difficult to imagine that the term was ever used to express more than the shape of the deposit ; and in order to* avoid the confusion caused by designating, two such different diseases with one name, Mr. Simon has suggested that of \u201c granular peritonitis,\u201d a term which avoids this objection, but equally indicates the peculiar form which the fibrine exhibits.\nWhen the plastic material has been mainly deposited on the walls of the cavity, and has included a considerable quantity of serum in its interior, an absorption of this fluid necessarily precedes the contact and adhesion of the opposed surfaces. But in the more diffuse and irregular coagulation previously alluded to, in which the serous portion occupied the meshes or interstices of the fibrinous net-work,, the latter may become organized, and may thus form cyst-like cavities, which are permanently filled with this fluid.\nIn'most instances, the serum having been absorbed, and the walls of the cavity having; been united by coagulable lymph, the latter becomes slowly organized into a substance which resembles areolar tissue, but contains comparatively little of the yellow fibrous element. Cotemporaneously with this change, vessels are developed in the mass by a series of processes, which, in all probability, closely approximate to those of their formation in the embryo. The resulting structure occupying what was previously the cavity of the serous membrane, effectually prevents the repetition of such an effusion ; although there is no reason to believe that it confers an abstract immunity as respects the inflammatory process.\nThe suppurative inflammation of the serous membranes frequently offers,.in its symptoms, or causes, few differences from the adhesive variety ; but the formation of pus is sometimes discoverable at so early a stage of the disorder, as to render it doubtful how far it may not be considered, not so much a mere form oir termination of the disease, but an inflammation sui generis. Where pus has been received into the bloodvessels, and circulated with their contents, large collections of this fluid are sometimes seen in these tissues; these are, however, to be distinguished from the suppuration which occurs primarily as the result of an inflammatory process. In the latter case, the cavity of the inflamed serous, membrane is usually lined by a soft, irregular, and membraniform exsudation, resembling the wall of an abscess, to which the altered tissue may, under these circumstances, be fairly COm-III m 4","page":535},{"file":"p0536.txt","language":"en","ocr_en":"536\tSEROUS AND SYNOVIAL MEMBRANES.\npared. The appearances of the pus present the varieties met with in this fluid generally.\nIn the most favourable cases, the .fluid rapidly diminishes in quantity ; and the pus-cells, which are incapable of further organization, disappear, the substances which compose them being, in all probability, absorbed subsequently to the breaking up of their structure ; while the remaining parts of the exsudation become organized together with the adhering walls of the cavity, and result in the complete obliteration of the serous structure.\nIn other instances, the suppurative process takes a more unfavourable course ; the pus assumes a sanious appearance and a very offensive smell ; and, finally, after ulceration or sloughing of the serous membrane, is discharged through the opening into the cavity of the viscus, or into a neighbouring serous membrane, or on the surface of the body.\nSometimes this process appears to be modified by the occurrence of a less complete absorption. The pus, deprived of certain of its constituents, is slowly transformed into a mortar-like mass, lining the membranous wall by which it appears to be secreted. The sandy or gritty consistence of this substance shows that it contains chiefly the inorganic constituents of the exsudation ; and sometimes the fluid, gradually thickening, passes into a cheesy pultaceous mass, and thence, by long duration, into a cretaceous substance, resembling that into which tubercle often degenerates.\nThe so-called chronic inflammation presents no differences which can be called essential ; most of them chiefly referring to the duration and intensity of the process, rather than to any peculiarities in its nature and appearances. For instance, if the general symptoms are less prominent than usual, and the disease progresses slowly, with frequent remissions and exacerbations, it is called \u201c chronic,\u201d So, also, the same name would be applied to a case which, originally \u201c acute \u201d in the intensity of its symptoms, and the rapidity of its progress, had overpassed the violence of the first attack ; the effusion remaining with diminished constitutional disturbance. Or a recurrence of the inflammation, pouring forth a new effusion in and within the already dense and hardened layer of a previous exsudation, is called chronic. In such a relapse, the unorganized exsudation has been said to be the seat of the secondary inflammation ; but it may be questioned how far the inflammatory process can occur in a tissue which is as yet unprovided with vessels : and even were the absence of these as complete as it seems to be, the inflammation of the lymph would scarcely be a necessary supposition, since it would be difficult to deny the possibility of a physical transudation of fluid, derived from the nearest vascular surface, or that of the original membrane.\nBesides these divisions of inflammation according to its duration and results, there are others, in which the process is compli-cated^ by its occurrence in connection with\nother diseases, or by its dependence upon some specific cause. Amongst these the \u201c haemorrhagic \u201d effusion, first recognised by Laennec, holds a very conspicuous place. In this disorder the inflammatory exsudation is mingled with more or less blood, which communicates its colour and appearances to the whole mass, in a degree varying with the quantity in which it is present. By longer duration, it separates into two parts : a peripheric layer of whitish or slightly-coloured lymph, which covers the serous surface ; and a fluid which contains the greater part of the blood corpuscles and serum, and is included in the cavity formed by the plastic layer. This liquid portion is only capable of a very slow absorption, and prior to this event it passes through many gradations of colour and appearance. Generally, it slowly loses its red colour ; butin the case of the haemorrhagic inflammations of the peritoneum, it very frequently becomes darker, and, finally, almost black ; a change which seems due to the action of the intestinal gases. This conjunction of inflammation and haemorrhage occurs in many diseases, but with the greatest frequency in tubercular ca-chexia, in fevers, and in other exanthemata. In all these disorders, the mass of the blood is greatly affected, and in many of them sufficiently so to exhibit marked deviation from the composition and properties of the healthy fluid. And in addition to these, the general conditions of its occurrence, Rokitansky * points out a local circumstance which greatly favours its access ; viz. the previous existence of a plasma, in which organization is commencing. And he refers this aptitude for haemorrhage to the probable state of its vascular apparatus, which, in this early stage of its development, offers simultaneously the greatest delicacy in the texture of its walls, and a deficiency of anastomosis with the neighbouring vessels ; two conditions which would respectively diminish its capacity of resistance to any distensive force, and increase the amount and duration of this distension. And in illustration of this his opinion, it may be pointed out, that a granulating surface on the exterior of the body seems closely to imitate these local conditions; while the resulting haemorrhage, often traceable to the congestion mechanically producible by posture, often depending on exciting causes of a more recondite nature, affords a parallel to some of the effusions noticed above.\nThe events of inflammation are mainly included in the preceding sketch of the effusion which constitutes its most important feature : in this manner adhesion, suppuration, ulceration, and more rarely sloughing, occur. But they also happen, though with less frequency, as secondary affections of the serous membranes, in connection with diseases of the viscera or cavities which they cover. Thus, a morbid process in the immediate neighbourhood of a serous membrane frequently causes\n* Handbuch der Pathologischen Anatomie, Band ii. S. 28.","page":536},{"file":"p0537.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\t537\na slight effusion, which is followed by an adhesion of its visceral and parietal layers ; an effect which is usually attributed to an \u201c irritation \u201d of the part by the disease. And as this process generally precedes any similar extension of ulceration to these membranes, it has the salutary result of sealing up their interior, and thus of preventing what would otherwise be a serious or even fatal effusion into their cavity. Their destruction by the communication of an ulcerative process in their immediate proximity may be called by the same name ; but it often more resembles sloughing in the rapidity of its course, and in the imperfect absorption of the broken down textures. So also where softening of these tissues happens, it almost invariably depends upon an action which primarily affects the subjacent viscera, and gradually implicates their serous covering.\nTubercle. \u2014 The deposit of this morbid product in the cavity of a serous membrane constitutes but a part of the general tubercular cachexia; and in the majority of instances, it only occurs after the disease has been localised in some other organ ; often, indeed, after it has already implicated the respiratory apparatus. And even in those cases in which its symptoms precede other manifestations of the disease, it appears extremely probable that the lymphatic glands of the immediate neighbourhood have been the original seat of the deposit, and that from thence it has, as it were, extended to the particular serous membrane.\nOccasionally, the tubercular matter is deposited in and amongst the effused products of inflammation, so that the two processes appear to merge into each other, with a similar mingling of their products. This occurrence of tubercle in connection with inflammatory exsudation has been minutely described by Rokitansky, who considers that a complete metamorphosis of the latter substance into the former does, in some instances, obtain. But from the difficulty of procuring direct evidence upon this point, i. e. of examining different portions of the same effusion at different periods of its duration, one may be allowed to doubt whether such a transmutation, or even a substitution, is really effected.\nGenerally speaking, the coexisting inflammation plays a more subordinate part. Where the tubercular matter is thus comparatively uncomplicated, it occurs in the form of greyish semi-transparent granulations, of about the size of a millet-seed, or rather larger. The situation of these is usually on the inner surface of the membrane, which they render irregular by their presence, so that on removing a tubercle (which is easily peeled off from the subjacent texture), a depression of a size which corresponds to it is exposed, in which the serous membrane has lost its smooth and shining character, and has become dull and somewhat opaque. Besides this, which is the ordinary form of tubercle in these textures, other and smaller\nvarieties often occur : and where a large quantity of the deposit is present, more or less exsudation unites the whole into a layer ; in which, however, the granularity of their developement can still be discerned. Usually, a certain amount of serous fluid is also present, the quantity of which has some relation to the extent of the disease. In the peritoneum, however, its quantity is for the most part insignificant ; and the cavity of the serous membrane is completely filled by a thick and solid, yet granular mass of tubercle, by which the viscera and abdominal parieties are completely matted together. Sometimes, but rarely, the texture of the serous membrane itself, or the subserous areolar tissue, becomes the seat of the deposit ; in these cases its quantity is small. The after-changes of tubercle in these tissues may lead to suppuration and ulceration, or to a slow absorption of the organic constituents of the mass, and a cretification of the remainder ; but in the greater number of cases, the patient dies of the general disease without either of these events having happened.\nCancer of these tissues is comparatively rare : and of those instances which do occur, many are scarcely affections of the serous membranes themselves, but ought rather to be considered as secondary, and dependent on a mere local proximity. Thus, a neighbouring cancerous tumour, by the progress of its growth, conies into contact with a serous membrane, and, as its size increases, gradually implicates this structure in its own diseased mass. Sometimes they are primarily attacked ; yet even here, other organs generally suffer at the same time, and either complicate or mask the local disease.\nThe carcinomatous deposits themselves offer few special peculiarities of appearance. The harder or scirrhous forms are seldom seen ; the softer varieties, viz. the gelatini-form or areolar, the medullary, and the melanotic, being those to which they are most liable. For a description of these the reader is referred to the article Adventitious Products.\nOssification of the serous membranes is also infrequent. Like the same process elsewhere, the deposit of bony matter never occurs alone, but is a very slow change, which appears to require the existence of a previous tissue. Hence, it is limited to two forms, neither of which primarily affect the cell-growing membrane. In the first, the fibrinous exsudation of a preceding inflammation is gradually transformed into ossifie matter. In this case, the shape of the deposit is rough and irregular, and sometimes it forms a kind of nucleus, which occupies the centre of the tough fibrous mass. Its appearances sometimes approximate to those of the cretification before alluded to, as possibly do the several processes which form these substances. In the second variety, the subserous and neighbouring areolar tissue is occupied by the deposit ; but here also","page":537},{"file":"p0538.txt","language":"en","ocr_en":"538\tSEROUS AND SYNOVIAL MEMBRANES.\na fibrous or fibro-cartilaginous thickening, which is itself the developement of an exsudation, is probably the immediate seat of the change ; and a variable quantity of this morbid tissue is generally seen around and upon the bony matter. The shape which, under these circumstances, it assumes, is somewhat more regular than that of the preceding variety, it being often flattened and extended in thin plates, the roughly tuberculated surface of which is, for the most part, parallel with the surface of the membrane.\nThe pleura is the most frequent site of these ossifications, as it is also of the adhesions in which they mainly occur : but thefy are also found in the subarachnoid tissue and pia mater ; and, more rarely, in the peritoneum and the synovial sheaths of the tendons.\nCysts are often found in these membranes, but their great differences of nature and causes claim a longer notice than can be accorded in this brief sketch. Three chief varieties may be distinguished. One of these is inhabited by parasitic animals, as the echinococcus. These are usually found in great numbers, and may occur in any of the serous membranes, although the peritoneum is their most frequent locality, probably from its proximity to the intestine by which they are introduced into the body. Sometimes they occupy the cavity of the membrane, and are in contact with its interior by a slightly flattened part of their surface; in other instances, they project into the cavity, carrying the membrane before them $ and at least one layer of their wall is formed by lymph derived from the neighbouring vessels Another form is not recognised as parasitic, but in the present state of our knowledge might rather be described as a gigantic cell, w'hich often includes a vast progeny of smaller ones. The whitish powder which some of these contain, may frequently be seen to be completely composed of small cells, which are devoid of a nucleus, of uniform size and spherical shape, and exhibit a clear sharp outline. These characters alone would, perhaps, indicate their merely cellular nature, as above stated ; but the general appearance of these contained globules is suspiciously like the ova of entozoa. In other cases, the included cell again includes a smaller one, and this yet another, so as to form a series of concentric hollow spheres ; an arrangement which has named them as the pill-box hydatid. In their general appearances, they closely resemble the preceding variety. The fluid contents of both are limpid and transparent, and are composed of water, with blood salts (chiefly chloride of sodium), and an exceedingly small quantity of albumen. Yet the effusion of this apparently harmless fluid into the serous cavities gives rise to an inflammation of the greatest violence and fatality. In a third class of cases, the cysts are usually in much fewer numbers than the preceding : they occur for the most part in the neighbourhood of the female reproductive organs ; and this\ntheir situation, together with their contents, which often consist of teeth, hair, bone, fat, and other products of an abortive development, sufficiently indicate a relation to the generative process. The fluids which they contain are albuminous, often sufficiently so to possess a glairy consistence. They exist within the cavity of the serous membrane, or in its texture, indifferently ; when developed in or beneath the subserous areolar tissue their gradual enlargement causes them to reach the free surface of the membrane, and then to dilate and extend this tissue before them, until finally the cyst, still covered by the serous layer, hangs freely in the cavity by a more or less elongated peduncle, which is formed by this covering where it becomes continuous with the rest of the serous membrane.\nThe subserous areolar tissue has been mentioned as implicated in most of these diseases ; but other morbid conditions are not wanting, in which it appears to be affected without the essential participation of the remainder of the tissue. Such are the little masses of fat which are occasionally found projecting into the serous cavities ; they are covered by the smooth and apparently healthy membrane, and their form is generally pedunculated, or sometimes ramified and arborescent. The development of this shape corresponds with that of the subserous cysts just mentioned. The fibrinous Pacchionian bodies of the cerebral meninges have been similarly explained as arising from the pia mater, and gradually invested with a layer of arachnoid which becomes converted into a peduncle, the rupture of which leaves them adhering to the dura mater, or even projecting into the longitudinal sinus.\nLoose cartilages. \u2014 The cavities of the serous and synovial membranes sometimes contain morbid products in the shape of certain free or unattached substances, which, from their usual appearance and consistence, are best known as \u201c loose cartilages.*\u2019 The most frequent situation of these bodies is in the knee-joint, and next to this, in the synovial sheaths of the flexors and extensors of the hand or foot ; but they are not uncommonly found in the subcutaneous bursae over the patella, trochanter, or acromion. More rarely they are seen in connection with the serous membranes; for instance, in the tunica vaginalis testis, or in hernial sacs. They may also exist in the diarthrodial species of false joints.\nTheir appearances offer great variety in different cases. In some instances, as often happens in the knee-joint, only one, or perchance two such bodies are present. Here they are of considerable size, attaining the magnitude of a large bean or almond ; their shape is a more or less flattened oval, and their surface is smooth and slippery. Their consistence is firm and elastic, their appearance whitish and cartilaginous, their substance uniform and structureless.\nWhen comparatively recent, or of only a","page":538},{"file":"p0539.txt","language":"en","ocr_en":"539\nSEROUS AND SYNOVIAL MEMBRANES.\nfew weeks\u2019 or months\u2019 standing, they may vary somewhat from this description by the possession of a rough surface on one side, which indicates the seat of their previous attachment to one of the bones of the leg. The observations of Cruveilhier * have furnished us with a knowledge of the stage which, at least in some instances, immediately precedes this condition. He has shown that, in some cases, the development of these bodies occurs in the subserous or rather subsynovial tissue ; that their enlargement carries forward the synovial membrane ; and that a peduncle is thus formed, the rupture of which sets them free, in the articular cavity.\nThere are other cases which possibly represent a different class, and which are distinguished from these by the characteristics of the greater number, lesser size, and, for the most part, much softer consistence of these bodies. Their general features have long been known to anatomists, and recently the minute descriptions of Bidder']' and Hyrtl J have added important, though apparently conflicting, details concerning them.\nIn the case which Bidder has narrated, the morbid product was removed from the knee-joint during the life of the patient, so that the appearances of the synovial membrane are necessarily wanting. The mass consisted of granules, the shape of which was always a flattened oval ; and their size offered a similar uniformity, the length of the oval being about one-eighth of an inch, and this about double and treble its width and depth respectively. Their surface was smooth and shining, their colour yellowish-white, and a viscid fluid in sparing quantity (probably synovia) united them into small clumps or masses. In consistence, they were softish, yet highly elastic, resuming their original size and shape immediately after the removal of a flattening pressure. A microscopic examination showed them to consist of an uniform substance, and to be entirely devoid of all traces of organization. Their chemical reaction was that of an albuminous solid ; \u2014-viz. they were unchanged by water or ether, were shrunken by the application of alcohoi, and were swelled out into a transparent mass by acetic acid. The substances described by Hyrtl differed in many important respects from the preceding granules. The synovial sheath of the flexor tendons was distended, so as to form a protuberance above and below the annular ligament of the wrist. Pressure on either of these swellings alternately gave rise to a predominance of the other one, and was attended by a kind of crepitating sound. On laying open the sheath, its interior was found to be occupied by upwards of a hundred\n* Patholog. Anat. ii. 2. p. 211.\nI Henle und Pfeuffer\u2019s Zeitschrift, 1845, Band iii. lieber Entstehung fester K\u00f6rper in den von Sy-novialha\u00fcten gebildeten H\u00f6hlen.\nX Oesterreiche Medizinische Jahrb\u00fccher, Bd. xxxix. S. 261. Anatomische Untersuchung einer sogenannter Hydatiden Geschwulst des Schleimbeutels der Beugesehnen am Carpus.\nsmall bodies, which in their colour and general appearance seem to have greatly resembled those described above ; but their consistence appears to have been softer, their size less uniform, varying from that of a hempseed to a lemon-pip, and their flattened shape was, in most instances, altered by the possession of an elongated extremity, although others were more globular. The sac itself exhibited very interesting appearances. The tendons, where they passed through it, were greatly diminished in bulk. The parietal portion of the sac appeared to consist of two layers, a serous and a fibrous, the latter of which was dense. (Probably this appearance was partly due to a condensation of the neighbouring areolar tissue by pressure into a membranous form, similar to that seen in the sac of an aneurism.) The synovial membrane, where it covered the tendons, was looser than natural, and had lost its smoothness and polish, while in many places it had acquired a villous appearance. In the subserous areolar tissue, little knots were seen, many of which projected into the sac, carrying before them a covering of the serous membrane ; others of them had rather a constricted neck ; and, finally, in others this constriction had increased so as to form a peduncle of little more than the thickness of a hair. The severance of this connection brings these bodies to the same condition as the granules which were found free in the cavity ; but the bulk of many of these was larger, while those yet in connection with the sac were uniformly of small size. This larger size of the unattached bodies was also noticed by Morgagni. The minute anatomy of both the free and attached substances was the same. Their surface was clothed with an epithelium of angular flattened cells, and their interior contained areolar tissue and fat, with a grumous coagulated substance. These two normal tissues, however, were not in a healthy state ; the fat cells were wrinkled, their contents half solidified, almost opaque, and of a sordid yellow colour ; the areolar tissue was alike destitute of regular arrangement and of its ordinary wavy lines ; while with all this was mingled much amorphous debris.\nConcerning the mode of formation of these substances considerable differences of opinion have prevailed, which may justify a slight notice in this place.\nThe descriptions of Cruveilhier, Hyrtl, and others, leave no doubt as to what is the process of their development in at least a large proportion of instances. These exhibit them as affections of the subserous, or rather sub-synovial areolar tissue ; while the circumstances under which they are found, such as the arrangement of the deposit in small masses, which are plentifully scattered over a large surface, the aged and debilitated constitutions in which they are chiefly present, &c., indicate with tolerable clearness that they are the result of disease, as contradistinguished from external violence.\nBut it may be doubted whether this expia-","page":539},{"file":"p0540.txt","language":"en","ocr_en":"SEROUS AND SYNOVIAL MEMBRANES.\n540\nnation will apply to these unattached bodies universally : it seems more probable that amongst these substances are included some which have not only a different origin, but also a different relation to the synovial membranes.\nThus, it was imagined by Hunter* that \u201c the loose cartilages usually found in the knee-joint originated from a deposit of coagulated blood upon the end of one of the bones, which had acquired the nature of cartilage, and had afterwards been separated.\u201d He conjectured that their pedunculated shape during the period of their attachment depended on the movements to which such deposits were liable during their soft condition ; and in confirmation of this he adduces an instance in which some blood effused in the abdominal cavity acquired a peduncle half an inch in length before it lost its red colour, and, when washed, exactly resembled a pendulous tumor. And as to the possibility of the transformation of such an effusion into a cartilaginous-looking substance, reference is made to \u201c an examination of joints which had been violently strained or otherwise injured, where the patients had died at different periods after the accident. In some of these there were small projecting parts, pre-ternaturally formed, as hard as cartilage, and so situated as to be readily knocked off\u2019 by any sudden or violent motion of the joint.\u201d The frequent connection of this variety of loose cartilage with external violence has long been known, and in some of these cases symptoms of local inflammation mark the period of their formation ; while, after a certain interval, the accident of their separation occurs, attended by the ordinary effects on the movements of the joint.\nThese facts, however, while they afford a great probability that external violence may operate as a cause of these growths, by giving rise to an effusion, which in some instances consists, it is most likely, of blood ; yet they do not exhibit the relation of this effusion to the synovial membrane. But it may be conjectured from the situation and arrangement of the vessels, that a sudden hemorrhage, to any perceptible amount, would necessarily imply the rupture of this delicate tissue, and the consequent presence of the effusion in its cavity ; while a smaller or slower process would carry the membrane before it ; or, in other words, that the presence or absence of the serous covering would chiefly depend on mechanical conditions ; and that, in either case, the result would be little affected.\nIndeed, the synovial membrane itself cannot be considered immediately essential to the formation of these substances 3 another vascular surface may be substituted, the result continuing the same. Thus, Sir Everard Homef mentions a case in which thirty or forty such substances were found loose in the cavity of a false joint, having apparently been\n* Transactions of a Society for the Improvement of Medical and Surgical Knowledge, vol. i. p. 231.\nf Loc. cit.\nmechanically broken off from a number of projecting portions of cartilage, which studded the broken ends of the bones, leaving exposed interstices. Although slight variations in the size and shape of these substances, and more considerable differences of their consistence, are spoken of, yet their description essentially coincides with that of the preceding bodies examined by Bidder.\nTaken altogether, these facts seem to indicate that the unattached substances which are found in these tissues include the products of very different pathological conditions and processes. They appear to show that morbid deposits beneath the synovial membrane, effusions the result of violence, and either occurring beneath it, or by mechanical extension in its cavity, and finally, irregularly formed cartilage, may all, under certain circumstances, give rise to the production of these substances.*\nThe conditions essential to their transformation seem to be of a twofold nature, mechanical and physiological ; exposure to pressure and movement, and the presence of a synovial fluid. It is doubtful how far the acquisition of the peduncle noticed in some, may depend on the joint influence of their extensibility, and the mechanical violence which must be exerted on such isolated prominences. But the separation, whether of these, or of those seen in the false joint, is obviously the direct result of violence. Pressure seems an important condition, so much so,, that a close relation may probably be traced between its amount and the degree in which they have assumed the cartilaginous form and consistence ; the synovial sheath, the knee-joint, and the false joint appear to present gradations in both these respects. And as to the operation of the synovial fluid, similar probabilities may be deduced. The mere permanence of these bodies seems to point out that they possess some kind of nutrition; and the increased bulk noticed by Hyrtl in the unattached as compared with the attached substances, would still further necessitate such a supposition ; their structure sufficiently denying the suggestion that the increase is due to the union of two or more. And in the case described by Hyrtl, the structure of these bodies seems to show that the results of a previous organization are not exempt from this transforming process, but may undergo a degeneration into a cartilaginous substance. And in the absence of any inherent or chemical capacity of their contents for such a change, this would yet more require the supposition of an agent of nutrition, which should supply the materials, if it did\n* I may, perhaps, mention, that since writing the above, I believe myself to have verified the conversion of bone into these structures. The change was partial, and the vessels seem the immediate agents of the process, since not only did a superficial stratum of cartilage occupy the whole surface of a pedunculated and cartilaginous structure, but a layer of nearly equal thickness surrounded the vessel in each Haversian canal. See Medical Gazette of Dec. 8.1848.","page":540},{"file":"p0541.txt","language":"en","ocr_en":"SESAMOID BONES.\t541\nnot effect the metamorphosis. While the complete isolation of these bodies from the vessels which are the immediate channels of nutrition, leaves only one supposition, viz., that the synovial fluid is the pabulum from which they derive the materials essential to their permanence, growth, or alteration. The composition of this fluid as compared with their own, perhaps sufficiently warrants this conclusion.\nOther conjectures as to the mode of their development are offered by Bidder, such as the possible precipitation of synovia around an epithelial cell, the gigantic development of a cell, or, what much approximates to this, their hydatid nature.\nIn certain abnormal conditions of the articular cartilages, peculiar appearances of the synovial membranes are seen, although it is somewhat doubtful how far they can be regarded as essentially morbid.\nThus, for example, in the ulceration of diar-throdial cartilages, it appears probable, that the removal of their substance is chiefly accomplished by the synovial membranes. Cruveilhier * narrates a case in which purulent fungosities of this tissue replaced the destroyed cartilages of the ankle-joint; and the general connection of hypertrophy of the membrane with ulceration of the cartilage has long been known. More recently, Mr. Good-sir\u2019s f investigations have thrown much additional light on this subject. He has shown that the preternaturally active growth of the cartilage, and the similarly rapid change of its properties and appearances, are to be regarded as inherent in this tissue itself ; that where the destruction of its substance occurs at its margin, or in the immediate neighbourhood of the vessels, a fungous enlargement or extension of these accurately fits into the eroded part ; but that in the ulceration of the centre of the cartilaginous lamella, such a physical adaptation is absent. From these circumstances it seems probable that the absorption which is accomplished in the former case by the local enlargement, is in the latter shared by the vessels of the synovial membrane generally.\nA somewhat similar, but much less prominent affection of vascularity has been described by Dr. Todd J in the porcelain-like condition of these cartilages, which often obtains in the chronic gout of the aged. The highly injected vessels of the synovial membrane were covered by a whitish powder, which was doubtless a frictional detritus of the diseased cartilage. How far this congestive state is connected with the absorption of this powder, is unknown.\n( William Brintonl)\nSESAMOID BONES. By this name are designated the small bones met with in the neighbourhood of certain joints, generally in the tendons of the adjacent muscles. They\n* Archives Generales de M\u00e9decine, vol. iv. p. 161.\nf Anatomical and Pathological Observations.\nJ Medical Gazette, 1847.\nowe their name (rrrjcrafiri si\u00c6o\u00e7) to the figure which they usually possess, resembling that of an Indian grain called sesame. But the present application of the term regards the character of their situation in the course of a tendon, rather than their form ; for instance, the patella is often said to be a sesamoid bone, not because it resembles sesame, but because it is placed in the tendon of the extensor cruris muscles. This character of their situation in the course of tendons constitutes their chief point of interest ; it is in this that they are peculiar, and different from other bones.\nIn the human subject these bones are usually met with only on the palmar aspect of the metacarpo-phalangeal joint of the thumb and the homologically corresponding part of the great toe, in both of which situations there are usually two. These are not constantly present, and, according to Cloquet, are not met with in children, owing, probably, to their becoming ossified late, though in young Ruminants and Solipeds, as well as in other animals, I have found their ossification as far advanced as it was in the other bones. They are more frequently absent in the hand than in the foot, and in females than in males. The long flexor tendon of the thumb or great toe passes between them, and the two are bound together above and below it by dense fibrous tissue, so that they assist in forming its sheath.\nThe sesamoid bones of the thumb are very small\u2014usually not bigger than the half of a large pea. They have a somewhat oval outline, are convex on their palmar, and slightly concave on their dorsal aspect, which is articular, and covered with cartilage. They articulate with the head of the metacarpal bone. Those of the great toe are each as large as a horse bean, of a long oval outline, convex on the plantar aspect, and presenting a concave cartilage-covered surface to the head of the metatarsal bone, to which they are adapted.\nThe little pieces of bone, situated and shaped as above, are enclosed in the tendons of the short flexor muscle of the thumb or great toe, the fibres of which have the following relation to them : \u2014 Some of the tendinous fibres pass over them, and some on each side, whilst their articular cartilage, as I have verified by microscopic examination, becomes mixed with tendinous fibres, passing on their arthrodial aspect, as it approaches the bone. The greater part of the tendon, however, is inserted into their proximal, and arises again, so to speak, from their distal end. The arthrodial surface of their articular cartilage forms part of the synovial surface of the subjacent metacarpo phalangeal joint, and they are held in their place by the strong fibrous tissue of the common synovial capsule.\nStructure. \u2014 The sesamoid bones consist of finely cancellated osseous tissue, enclosed in a shell of denser bone. The main direction of the osseous columns that surround the can-celli is longitudinal, but they intercommunicate in all directions. These columns are much","page":541},{"file":"p0542.txt","language":"en","ocr_en":"542\nSESAMOID BONES.\nstouter towards the external part than towards the inner or that which is in contact with the long flexor tendon.\nA microscopic examination of sections, taken in the three cardinal directions, shows that they possess much the same minute structure as other similarly shaped bones. The lacunas are large and expanded*, the canaliculi distributed arborescently, except a few in the immediate neighbourhood of the cancelli and Haversian canals, where they have the straight and parallel arrangement met with in the shafts of the long bones. The Haversian canals are but few in number, their place being plentifully supplied by the numerous cancelli. The dense surrounding shell is stratified parallel to the surface, very markedly so on the articular aspect, where it is thickest. At the points where tendinous fibres are attached, it appears to be laminated at right angles to the strata and the surface, as though the fibres of the tendon were received between the plaitings of osseous laminas, or conversely as though the ossification had extended up in laminae between the tendinous fibres. The lacunae that occur in this crust are mostly large and clumsy, elongated and directed vertically or obliquely towards the surface, particularly the articular surface, and all of them destitute of canaliculi ; a condition met with in the superficial osseous crust of other articular surfaces, and points of attachment of tendons, especially in old subjects.\u2014 It is probably the form of osseous tissue that results from the ossification of permanent cartilage or white fibrous tissue ; but my researches, in order to ascertain this point, have not been sufficiently extensive.\nDevelopement (examined in young Ruminants).\u2014 A small mass of temporary cartilage precedes the osseous condition of these little bones. This becomes ossified from a single central point in the manner of an epiphysis, as described at page 857. YoI.III. art. Osseous Tissue.\nDisease and injury.\u2014 I am not aware that the diseases or accidents affecting the sesamoid bones have ever been noticed, unless the patella be considered a sesamoid bone, which, indeed, it is in structure, by situation in a tendon, and in function. This bone comports itself in disease just as other bones do (see Knee Joint, Abnormal Anatomy). When fractured transversely, it presents the peculiarity of uniting, by white fibrous tissue, instead of by bone. I cannot regard this nonunion by osseous tissue as resulting from any deficiency of nutritive or reparative power in the patella, for new fibrous tissue is always, and when the fracture is longitudinal, even new bone is usually, formed ; nor from want of apposition, for in many ununited specimens the apposition is very perfect. Osseous union, as a result of reparative inflammation, never occurs in situations where the new material of repair is not subjected to pressure, as in the skull, acromion, olecranon, heel,\n* See Yol. HI. p. 850. fig. 452. art. Osseous Tissue.\n\u2014 a hole made in the scapula does not become filled up with bone. I therefore regard the non-union by bone of transverse fracture of the patella as due to the absence of that stimulus (pressure) which I conceive to be necessary in order to determine the reparative material to assume the osseous form ; whilst I attribute the union by ligament to the presence of the stimulus (tension) which I regard as necessary, in order to direct the metamorphosis of the adhesive lymph, or rather the mass of new corpuscles or cells, which is formed for the purpose of repair, soon after any accidental breach of continuity has been produced, towards the ligamentous form. These remarks would, of course, apply to transverse fractures of the sesamoid bones properly so called, in case such accidents ever occur.\nOther sesamoid bones. \u2014 Sesamoid bones are occasionally met with in the human subject in other than the above-named situations. One is sometimes found at the distal joint of the thumb and great toe ; two at the proximal joint of the forefinger and second toe ; and one at the corresponding joint of the little finger and toe. There is pretty frequently one, or even two or three, in the heads of the gastrocnemius, just at the posterior part of each condyle of the femur. An ossification often takes place in the tendon of the peroneus longus, just where it doubles round the os cuboides ; and a small bone is not un-frequently found in the tendon of the tibialis anticus, near its insertion into the scaphoid.\nComparative anatomy. \u2014 Sesamoid bones at the metacarpo-tarso-phalangeal joints exist in much greater number in the quadruped mammalia than in man ; and they seem to be largest in animals that are digitigrade in their progression. I have not had an opportunity of scrutinizing their condition in the Quadru-mana ; none are preserved in the skeletons, and as the thumbs are somewhat rudimentary they are probably absent. In the Seal, a pair is situated on the metatarsal joints of both the hallux and the fifth toe, which greatly exceed the other toes in size ; but there are none in the fin-like hands. They do not exist in the paddles of the Cetacea nor in the singularly modified extremities of the Sloth. In all, or nearly all, other Mammalia a pair occurs opposite every metacarpo- and metatarso-phalangeal joint. The two bones of the pairs are not unfrequently anchylosed together, as in the outer digit of the hand and foot of the Elephant. They are always situated in the course of the tendons of the interossei muscles. Often, however, as in Ruminants, their large size is enormously dis-proportioned to the small tendons on which they are placed, which, in this order with their muscles, are quite rudimentary, and the large sesamoid bones seem to be embedded in the sheath of the long flexor tendons. In Birds their place is occasionally supplied by large masses of fibro-cartilage. In Reptiles they are wanting.\nThe patella exists in all placental Mammals,","page":542},{"file":"p0543.txt","language":"en","ocr_en":"543\nSEVENTH PAIR OF NERVES.\nbut is absent in many Marsupials. In Birds it is usually, but not invariably, present ; there are even sometimes two, one placed above another. In those aquatic birds which have the tuberosity of the tibia prolonged upwards as a large process, a patella is always found placed just behind it *, sometimes _ closely adapted to it, and extending beyond it so as apparently to form its summit.']' No patella has been met with in any reptile.\nOther sesamoid bones. \u2014 Opposite the plantar aspect of the distal joint of the fore and hind foot of Solipedes, there is a long supernumerary bone, called by farriers the shuttle bone, placed transversely. This, like the sesamoid bones above described, enters into the composition of the subjacent joint ; a broad slip of the perforans tendon is inserted into its proximal side, whilst on the distal side a portion of the synovial capsule alone, and that not so strong as one would expect, attaches it to the ungual phalanx ; the main part of the tendon passes over it to be inserted into the ungual phalanx, leaving a cavity lined by a synovial membrane between itself and the sesamoid bone in question. This bone reminds one of that which, as above mentioned, is occasionally found at the distal joint of the thumb and great toe in the human subject.\nSmall bones are found in one or both heads of the gastrocnemius in all Mammalia except Man, the Seals, Pig, and all Ruminants but Cervus, in which genus they are found, yet only in the external head of the muscle.\nA sesamoid bone is met with in the insertion of the tendo Achdlis of certain Birds, as the capercailzie J ; and the tendons of the legs of birds are very commonly ossified, not, however, where they correspond to the joints.\nUse. \u2014 Sesamoid bones serve much the same purpose as processes for the muscles that are inserted into them, without the inconvenience inseparable from a process, of giving an angular form to the joint. They also protect the long flexor tendons at points where perhaps they might be injured. But after all, taking into consideration all the facts related above, and many others that have presented themselves to me in the course of this inquiry, I cannot but believe, that some higher law than that of adaptation concurs in determining the presence, if not the size, of even these little bones.\n(S. R. Pitlard.)\nSEVENTH PAIR OF NERVES (Siebenter Nerv, Germ. ; Le Septi\u00e8me Nerf, Fr.). In laying the foundations of the natural sciences, few circumstances would seem to have occasioned more serious and permanent embarrassments than the immediate necessity of indicating the various new objects which they presented by specific names, and the difficulty of finding suitable ones. A nomenclature based upon their properties, would, perhaps, readily have suggested itself ; but, generally speaking, the recognition of the object so\n* Vol. I. p. 286.\tf Meckel.\nX Vol. I. p. 288.\ngreatly preceded the discovery of its properties, that this attempt was almost impossible. In the science of anatomy, this was especially the case ; and a large proportion of the human structures were named, either according to their form, or, if this was not sufficiently defined, by their real or fancied resemblance to some previously known object; or failing this, by the proper names of their discoverers, however polysyllabic or uncouth they might happen to be.\nIn some one or other of these modes, the different parts of the complicated nervous centre received their various designations. But the cerebral nerves, although very similar to each other in the outward properties of their shape, size, and appearance, yet offered, by their fewness, a sufficient ground of distinction in the application of the ordinal numbers. By denying the claims of the olfactory lobes, and overlooking the fourth and sixth, the earlier anatomists made a smaller number ; but the arrangement of Willis, which is more usually adopted in the present day, counts nine of these soft round cords, and reckons them from before backwards.\nYet even this apparently simple method of distinction comes far short of real accuracy. Thus, some of the so-called nerves offer the essential structure of nervous centres ; and include, in addition to the ordinary nerve-fibres, those globular vesicles which modem physiology recognizes as the generators of the nervous force. In others of them, the limited resemblance implied by this numerical arrangement is modified by their arising as two or more roots, which subsequently, by their junction, form one nerve. While in the seventh nerve, which forms the subject of the present article, the close proximity of two such cords during a part of their course has led to their being united under one name ; although in their distribution, properties, and functions, they present a marked contrast with each other.\nThe facial and auditory nerves proceed together from the medulla oblongata to the bottom of the meatus auditoi\u2019ius internus in the petrous portion of the temporal bone. Up to this point they are included in the term seventh nerve ; but beyond this situation their courses widely diverge. In conformity with these differences, the following short account will describe them separately from each other. It will first mention such of their anatomical features as are manifest on simply laying bare theh surface, and will afterwards refer to the appearances afforded by a more artificial dissection or separation of their fibres. Subsequently we shall briefly examine the bearing of these their structural peculiarities, and the effect of their morbid changes, with a view to attempting the deduction of their function.\nThe auditory nerve is of a considerably softer texture than the facial ; a difference which is in great part attributable to the much more delicate neurilemma by which it is enveloped, but which is, no doubt, to some extent the result of a peculiarity of its constituent nerve-","page":543},{"file":"p0544.txt","language":"en","ocr_en":"SEVENTH PAIR OF NERVES\n544\nfibres. From the fact of its lesser consistence, it is frequently termed the portio mollis\u201d of the seventh nerve.\nIts apparent origin is close to that of the facial. At the upper part of the lateral surface of the medulla oblongata, a somewhat triangular depression exists, which is bounded in front by the olivary body, above by the lower border of the pons varolii, and behind by the restiform body. This shallow cavity has been termed by Vicq d\u2019 Azyr \u201cthe fossa of the olivary eminence,\u201d and in it appears the commencement of the auditory nerve.\nUn dissecting out this origin, however, it may be separated into two portions or roots. One of these immediately penetrates the restiform body at a right angle to its surface,-and sinks into the central grey matter of the medulla oblongata : while the other, continuing backwards superficially to the restiform body, winds round it to reach the floor of the fourth ventricle, where this structure is deficient. By this latter root, the nerve seems to be directly continuous with the tranverse white fascicles of the calamus scriptorius ; and near the middle line, it sinks into the posterior part of the same grey mass of the olivary columns, into which the other portion was followed.\nBut considerable variations appear to prevail in the degree of the visible continuity of this root with these transverse white striae. Thus Meckel and Prochaska remarked that they are sometimes wanting; while Longet* confirms their statements, and adds, from the experience of himself, Serres, and others, cases which show that not only is their number variable within certain limits, but that, even where present, they may not unite with the root of the auditory nerve, but may curve upwards at their extremity, and pass up the posterior surface of the mesocephale. One or two examinations made by the author of this article seem to show that this is by no means unusual.\nOther and more complicated origins have been ascribed by various anatomists to the auditory nerve. Thus, according to Fovillef, a thin and white nervous lamina, which is continued from its roots and from those of the filth nerve, is spread over, and as it were lines, the interior of the cortical grey matter of the cerebellum, in addition to covering the whole surface of the fourth ventricle and medullary velum. But in this and other descriptions of a like tendency, it seems difficult to distinguish how much of the connection observed was referrible to a mere physical contiguity of the soft nervous matter, apart from that unbroken continuity of nerve-tubules which we are probably justified in predicating of the cerebral nerves and their more immediate processes of origin.\nFrom the place of its first appearance at the surface of the encephalon, the nerve passes, in a direction which is at once forwards, outwards, and upwards, to the inner\n* Anatomie et Physiologie du Syst\u00e8me Nerveux, torn. ii. p. 84.\nf Trait\u00e9 Complet de l\u2019Anatomie du Syst\u00e8me Nerveux C\u00e9r\u00e9bro-spinal. Premi\u00e8re Partie.\nsurface of the petrous portion of the temporal bone, where it enters the internal auditory meatus. In this course, the flocculus, an isolated lobule of the cerebellum, is in close proximity with its outer side ; while on its inner side, and in front of it, is the portio dura, which slightly grooves this surface of the somewhat flattened auditory nerve.\nAfter entering the auditory canal, it continues along it to its termination ; and, finally, at the bottom of the meatus, it divides into two branches. The anterior of these is distributed to the cochlea : and the posterior, which exhibits a small gangliform enlargement, supplies the vestibule, dividing into three branches ; one for the posterior vertical canal, another for the sacculus, and a third for the utriculus, and remaining semicircular canals. These several divisions perforate the numerous foramina which are found at the bottom of the meatus to enter the internal ear; but as an account of their further arrangement with respect to the parts they supply would require a description of the auditory apparatus itself, the reader is referred to a previous article, \u201c Organ of Hearing,\u201d in which these details will be found included.\nThe facial nerve, the \u201c portio dura \u201d of the seventh pair, emerges from the same depression in the restiform body which was above described as giving rise to the auditory. It is of a much firmer and harder consistence than the latter, the tubules which compose it being connected by, and included in, a firm and strong neurilemma. Its real origin is generally referred to that central grey matter of the olivary columns to which so many of the encephalic nerves are traced. It is difficult to follow it any depth beyond these in a satisfactory manner ; but Foville considers that it may be traced in the transverse direction around the olivary column and anterior pyramid, and hidden beneath the lower margin of the pons varolii, to an origin from the inner border of the pyramid. \u2019He corroborates this by a reference to its comparative anatomy ; and states that the various stages of this course are successively laid bare by that diminished development of the lower arches of the pons which occurs in many of the mammalia. The description given by Morganti* somewhat differs from this, since he describes its roots as radiating by many filaments, ascending, descending, and transverse ; and the latter joining more deeply the central grey substance of the medulla oblongata near the floor of the fourth ventricle.\nThe description of the facial nerve may be conveniently separated into three parts : each representing a distinct stage of its course, which is accurately defined by its anatomical relations to the skull. The first of these is intra-cranial, and extends from the surface of the encephalon to the termination of the internal auditory canal. The second is osseous, and reaches from the latter point to the stylo-mastoid foramen, which forms the exit\n* Annali Universali di Medicina. Giugno, 1845.","page":544},{"file":"p0545.txt","language":"en","ocr_en":"SEVENTH PAIR OF NERVES.\t545\nof the nerve from the aqueduct of Fallopius. The third is extra-cranial, and includes its distribution on the exterior of the skull beyond this aperture.\nIn the cranium, the course of the facial nerve is comparatively short. From the restiform body it passes forwards, lying immediately beneath and in contact with the pons varolii, and taking the same direction as the portio mollis, which is external and posterior to it. It next enters the meatus auditorius internus in company with this nerve ; and finally leaves it by passing through the aperture at the upper part of the termination of this canal, and entering the aqueduct of Fallopius.\nPortio intermedia.\u2014With this part ot the auditory and facial nerves a third portion is visibly associated ; which is, in all probability, essentially distinct from both. Wrisberg first announced the existence of this nerve as a separate branch ; and from its occupying a position between the \u201c portio mollis \u201d and \u201cportio dura\u201d of the seventh, he named it the \u201c portio media \u201d or \u201c intermedia.\u201d It arises by two or three filaments from the restiform body, in the same locality as the neighbouring facial nerve, from which its deeper origin can scarcely be separated. Fo-ville, however, describes its ultimate visible fibres as traceable to a situation which is intermediate between that of the facial on the one hand, and that of the auditory oil the other. He thus considers these three nerves, the facial, intermediate, and auditory, as arising respectively from the anterior pyramid, the olivary column, and the restiform body ; or to use his own language, from the anterior, the lateral, and the posterior tracts of the medulla oblongata. Morganti\u2019s view of its origin closely approximates to this; but he places it more in connection with the vestibular nerve, and hence more externally. But whatever may be the differences of opinion as to its exact mode of commencement, it is tolerably agreed that it is in very close proximity to the facial nerve, so much so as at first hardly to be separable from it ; and that, at a further stage of its course, it is attached to the vestibular branch of the auditory nerve. Concerning its behaviour subsequently to this point, anatomists are less unanimous. Thus, some imagine that it-continues engaged in the auditory nerve, and accompanies it into the internal ear. Others regard it as returning to the facial nerve, and passing with it into the aqueduct of Fallopius. It is, however, sufficiently evident, that the only correct foundation of any of these views must be anatomical ; and since this method of investigation requires not only the artificial unravelling of the trunks, but also necessitates a frequent reference to portions and branches of the facial, as yet undescribed, its consideration is deferred until these shall have received some notice.\nIn the temporal bone. \u2014 The facial nerve, entering the aqu\u00e6ductus Fallopii from the internal auditory meatus, passes, for a very short distance, in a direction forwards, outwards, and slightly upwards, until it reaches\nVOL. IV.\nthe margin of the hiatus Fallopii on the upper surface of the petrous bone : it then suddenly bends backwards upon itself in the horizontal plane. Its next curve differs from the preceding both in character and direction, being much more gradually effected, and occupying a vertical plane. The termination of this bend reaches the perpendicular, and opens by the stylo-mastoid foramen on the under surface of the petrous bone, or between the styloid and mastoid processes. In the middle of this course the osseous tube of the aqu\u00e6ductus Fallopii projects into the cavity of the tympanum ; and the nerve thus passes successively along its roof, above the fenestra ovalis, and then behind the pyramid on the inner side of the cavity ; and, finally, down its posterior surface.\nAt the anterior of the acute angle formed by the first bend of the facial nerve in the aqueduct of Fallopius, it experiences a slight enlargement, which has been\u00bb called, from its position and shape, the \u201c intumescentia genu-formis.\u201d A dense and strong neurilemma here ensheaths the nerve, being a prolongation of dura mater, which is sent inwards on a minute vessel from the middle meningeal artery to enter the canal at the hiatus Fallopii. The swelling itself is of a greyish-red colour, but it is somewhat obscured by this thick covering of fibrous tissue. Its nature will be spoken of her\u00e8after.\nJust at this point, the superficial petrosal nerve is connected with the facial. Tracing it forwards from the intumescence, it is seen to pass at once through the neighbouring hiatus Fallopii, and thus it immediately gains the interior of the skull. Within the cranium it passes forwards, downwards, and inwards, lying in a groove on the outer or anterior surface of the petrous bone, and situated beneath the Gasserian ganglion of the fifth nerve. According to some anatomists, it occasionally passes amongst or through the meshes of the gangliform structure. Still beneath and internal to the ganglion, it is next placed immediately external to the internal carotid artery, where this vessel, emerging from the canal of the same name in the temporal bone, springs vertically upwards to form the commencement of the posterior limb of the sigmoid turn on the side of the sphenoid. It tnus enters the foramen lacerum basis cranii, perforating the cartilaginous substance which closes this bony orifice ; and in this manner it gains the posterior extremity of the vidian canal, which opens into the anterior aspect of this irregular opening. Finally, it continues along this canal to its anterior termination ; and is then prolonged horizontally forwards for a short distance to join Meckel\u2019s ganglion, which occupies this part of the spheno-palatine fossa.\nAnother nerve comes off from the same knee-shaped bend of the portio dura ; and as it appears from the same horizontal slit, or hiatus Fallopii, whence the preceding emerged, and occupies a very similar position with respect to the temporal bone, it has also been named \u201csuperficial petrosal,\u201d but is distin-\nN N","page":545},{"file":"p0546.txt","language":"en","ocr_en":"M6\nSEVENTH PAIR OF NERVES.\nguished, from its lesser size, as the \u201c small petrosal nerve.\u201d From the hiatus it is continued forwards and slightly inwards for about half an inch, running along the same surface of the temporal bone, but placed a little external to the preceding nerve. Arriving at the greater wing of the sphenoid, it perforates the bone by an oblique and minute orifice, which is situated between the foramen rotun-dum and ovale : and appearing on the inferior surface of the base of the skull, it immediately unites with the otic ganglion whieh lies on the inner surface of the third division of the fifth. During the latter part of this course it is accompanied by a filament from Jacobson\u2019s nerve of the glosso-pharyngeal. This branch, however, leaves the tympanum by a special canal, and is next placed externally to the lesser petrosal nerve on the petrous bone ; but, finally, it joins or runs with it to enter the same ganglion.\nA branch to the membrane which closes the fenestra ovalis is sometimes described as coming from the facial, where it passes, in the aqueduct, above this orifice.\nThe minute filament to the stapedius muscle is the next branch of this nerve. It leaves the portio dura and aquasductus Fallopii at about the middle of their second or vertical curve, or nearly on a level with the base of the promontory ; it next enters a small canal in this prominence, which conducts it to the proper osseous cavity for the muscle: it then breaks up and is lost in its substance.\nThe chorda tympani, the next connection of the portio dura, is a much larger nerve than any of the preceding branches; it leaves the trunk of the facial at a distance of about the third of an inch from the stylo-mastoid foramen. Tracing the portio dura in the upward direction, it is first seen to experience a slight thickening, and gradually, by the increasing laxity of the connecting areolar tissue, a tolerably large branch seems to extricate itself from the trunk at a very acute angle. Diverging still more, it now altogether quits the aqu\u00e6ductus Fallopii, and enters a short canal which is appropriated to it, and which is placed anteriorly and externally to the former cavity, occupying the base of the promontory. While yet at a considerable distance from the apex of this eminence, the nerve emerges from its canal by an orifice very near the osseous ring to which the tympanic membrane is fixed. It now crosses the tympanum from its anterior to its posterior part, and lying close to its outer wall, but covered by a reflection of its mucous membrane, and ascending as it goes, it passes between and at right angles to the long process of the incus and the handle of the malleus, to reach the processus gracilis of the latter bone ; along this process it continues during the remainder of its course in the tympanum. It next leaves the anterior wall of this cavity, and occupies a minute canal in the petrous portion of the temporal bone ; but it is still in close proximity to this process of the malleus, being only separated by a small interval of bone from the Glasserian\nfissure which contains it. It is next seen external to the cranium, after coming through the aperture of this canal anteriorly and internally to the fissure. In the remainder of its course it lies deeply in the pterygoid fossa beneath the ramus of the inferior maxilla, and is directed for about an inch downwards, forwards, and inwards, beneath the spinous process of the sphenoid, and the internal lateral ligament of the lower jaw attached to it, to join, at an acute angle, the outer side of the gustatory branch from the third division of the fifth.\nVery near the termination of the aqueduct of Fallopius, a minute twig connects the facial and vagus nerves. Following it from this cavity, it is seen to enter a small pore on its anterior surface, which conducts it by a short canal to the under surface of the petrous bone, where it emerges a very short distance in front of the stylo-mastoid foramen, and between it and the jugular fossa. The nervous filament now turns inwards and forwards in front of the jugular vein, and terminates by connecting itself with the pneumogastric, just below its ganglion in the dura mater of the foramen lacerum posticus.\nBesides these branches of the facial within the aqueduct, it appears pretty constantly to give off, while yet contained in this canal, a filament which passes inwards behind the jugular vein, and joins with the glosso-pharyngeal just below the ganglion of Andersch. Longet states that this branch, after its junction with the glosso-pharyngeal, may generally be traced to the digastric or st)lo-hyoid muscle, in which it often unites for the first time with this nerve by a kind of plexiform arrangement.\nExternal to the cranium. \u2014 On leaving the Fallopian canal, the facial nerve immediately enters that portion of the parotid gland which dips downwards behind the styloid process to reach the structures lying deeply at the base of the skull. The nerve next continues through the substance of the gland, being directed forwards and inwards to about its middle, where it divides into its temporo-facial and cervicofacial portions, the ramifications of which cover the whole side of the face, with part of the neck below and the head above. In its short course previously to this bifurcation, it gives off three branches, the posterior auricular, the digastric, and the stylo-hyoid nerves.\nThe posterior auricular, the first branch of the facial without the skull, passes upwards from the trunk of the nerve, and turns round the front of the mastoid process, lying at first rather deeply in a* depression between the auricle of the ear and this prominence, and being enveloped in a dense cellular tissue. Having gained the side of the head, it divides into two branches ; one of these continues backwards in the horizontal direction, above the insertion of the sterno-mastoid, and crossed by the lesser occipital nerve of the cervical plexus, to reach the posterior belly of the occipitofrontalis muscle, which it supplies : in this course it is covered by a dense fascia, and is","page":546},{"file":"p0547.txt","language":"en","ocr_en":"547\nSEVENTH PAIR OF NERVES.\nin close proximity to the artery which bears the same name. The remaining branch of the nerve takes a vertical direction, ascending perpendicularly behind the ear through the fleshy bundles of the retrahens aurem. To this muscle it is chiefly distributed ; but a few of its filaments continue to the posterior surface of the auricle, probably to supply its transverse muscular fibres. The trunk of the posterior auricular nerve, or some one of these its branches, is usually found to be joined by filaments of the great auricular nerve from the cervical plexus, and more rarely by some twigs from the lesser occipital branch of the same plexus. Arnold also describes a filament of the auricular of the pneumogastric uniting with it.\nThe two following branches not unfre-quently arise by a common trunk. The digastric, the larger of the two, leaves the facial nerve to penetrate the posterior belly of the digastric muscle, and supply it with many filaments. One of its branches, of more considerable magnitude, perforates its substance, and passing directly inwards, joins the glossopharyngeal immediately on its emergence from the skull. Other filaments of smaller size are said to join the superior laryngeal of the pneumogastric.\nThe stylo-hyoid branch, leaving the trunk of the portio dura near the preceding, passes downwards, forwards, and inwards ; crossing the styloid process obliquely, then running along the upper border of the muscle, and finally penetrating its fibres to be distributed to its interior. It is believed to unite, by numerous minute twigs, with the sympathetic around the neighbouring carotid vessels.\nAt the place of its division, the nerve occupies a position in the parotid gland which is superficial to the many other vessels and nerves found here ; and especially, at right angles to the external jugular vein and carotid artery.\nThe temporo-faeial division or branch is larger than the cervico-facial ; it passes forwards and upwards over the condyle of the lower jaw, and joins, towards the zygoma, with one or two large branches of the auriculo-temporal nerve. This comes from the third division of the fifth in the pterygoid fossa ; and the place of its union with the portio dura is in close proximity to the external carotid artery. The intimacy of the junction which connects the two nerves has probably led some anatomists to describe this temporo-faeial branch as giving many filaments to the front of the ear. These, however, with many others which ramify in the gland itself, belong to the associated branch of the fifth, and not to the portio dura.\nBeyond this its junction with the fifth, it is no longer possible to trace any special nerve, or to indicate its subdivisions by names, since, on the masseter, a succession of diverging branches are given off from it, each of which, by uniting with its neighbours above and below, and giving off fresh ramifications from the branches of union, forms part of a complicated network, in which the original con-\nstituent branches, and the respective shares which they take in the new loops, can scarcely be recognized. Cruveilhier and Bonamy have traced this looped arrangement still more minutely, having followed it into the smallest branches of the nerve, and especially into those which supply the orbicularis ; and it has been likened by them to the mode in which the mesenteric arteries break up to reach the intestine.\nNotwithstanding this free communication, however, the different portions of this reticulated arrangement may be conveniently regarded in succession, in order the better to appreciate their distribution.\nSuperiorly are the temporal branches ; these emerge from beneath the upper border of the parotid, and cross the zygoma to be distributed to the superficial.muscles of the auricle, the attollens and attrahens aurem, and to the anterior belly of the occipito-frontalis beyond these. The orbital branch of the second division of the fifth joins, by its long ascending filaments, with these branches of the facial; so also a perforating filament from the deep temporal of the third division, with others from the auriculo-temporal of the same portion of the fifth, are usually traceable to an union with this nerve.\nAnteriorly to these are the numerous orbicular or supra-orbital branches. They pass obliquely forwards and upwards over the malar bone, to supply the orbicularis palpebrarum, and corrugator supercilii muscles. Their connection with the fifth occurs chiefly by the supra-orbital and lachrymal of the ophthalmic division ; but others join the malar branch of the second division, where it emerges from its foramen in the malar bone near the outer angle of the orbit.\nThe infra-orbital filaments pass almost horizontally forwards from the temporo-faeial division towards the side of the nose. In this course, accompanied by the parotid duct, they cross over the masseter muscle; and more anteriorly, they pass beneath the different muscles which descend to the angle of the mouth and upper lip, and are distributed to them by numerous filaments which enter their deep surface. In this manner the greater and lesser zygomatic, with the proper and common elevator of the lip, and the elevator of the angle of the mouth, receive their nervous supply ; and the pyramidalis and transversale nasi also obtain filaments from this part of the facial. Many of these, in passing forwards, unite at right angles with the radiating bundles of filaments into which the infra-orbital nerve divides after leaving the foramen of the same name. Besides this union with the second division of the fifth, it unites with the ophthalmic by a small twig of its nasal branch, which appears between the lateral cartilage and the nasal bone, and generally by an infra-trochlear filament of the same portion in the angle of the eye.\nThe buccal branches, with the same direction as the preceding, occupy a position at a somewhat lower level on the face, in the neigh-N \\ 2","page":547},{"file":"p0548.txt","language":"en","ocr_en":"548\tSEVENTH PAIR\nbourhood of the transversalis faciei artery. They mostly terminate in the upper half of the orbicularis oris, and in the buccinator, on which muscle they join with the buccal branch of the inferior maxillary division of the fifth. This latter nerve is distributed to the mucous membrane and integuments, and probably has no share in the supply of the muscle. The lower of these buccal branches join another portion of the network, which results from the ramification and union of the next division of the facial.\nThe cervico-facial division, of smaller size than the temporo-facial, passes downwards and forwards from the seat of bifurcation of the portio dura, and emerges from the parotid gland near the angle of the lower jaw. Here it divides and subdivides in the same manner as the preceding portion. It is divided into a facial and cervical, or a supra and inframaxillary part.\nIts supra-maxillary part is constituted by one or two large branches, which, breaking up as they pass forwards to the interval between the jaw and mouth, enter beneath the platysma and triangularis menti ; and besides supplying these and the other muscles of this region, they join with a branch of the inferior dental which comes through the mental foramen.\nThe infra-maxillary, or cervical portion of the facial nerve, consists of two or three branches, which, directed still more obliquely downwards, soon divide into very numerous filaments. These pass beneath the platysma to gain the upper and anterior part of the neck, where they form looped ramifications, the most inferior of which are traceable in a vertical direction to a short distance below the hyoid bone. They are chiefly distributed to the platysma, and above they join with the neighbouring supra-maxillary branches just mentioned. They unite beneath the platysma with one, or more usually with two, branches from the superficial cervical nerve of the cervical plexus, which turns round the posterior border of the sterno-mastoid muscle to supply the integuments of the same part of the neck.\nLittle can be said with respect to the exact nature of these very numerous junctions of the facial nerve, either with the terminal branches of the various divisions of the fifth, or with the cutaneous nerves of the cervical plexus. They offer a very obvious anatomical resemblance to that intermingling of diff\u00e8rent nerves which constitutes a plexus; but without here specifying other distinctions, it may suffice to point out that, in many instances, the branches of the facial seem visibly continued in their previous direction beyond their connections with the fifth. In the absence of more minute investigations, this apparent independence can only be received as indicating a partial involvement of the two nerves, or an incomplete mixture of their fibres, in which one gives to the other, or each gives to each, a small number of its filaments, but retains the large majority.\nWe next proceed to consider those minuter\nOF NERVES.\nfeatures in the anatomy of the seventh nerve, which require a more artificial dissection or examination for their verification.\nThe origin of the portio intermedia, rather more externally than the facial, has been already spoken of, and the nerve was then traced to an union, more or less complete, with the neighbouring vestibular portion of the auditory nerve. Beyond this point the views adopted respecting it, from being somewhat conflicting, become absolutely discordant.\nThe very different nature of the numerous opinions upheld by various anatomists precludes the possibility of enumerating them here at full length. Some of these, however, have been already very briefly noticed ; and perhaps, on the whole, the most prevalent was that which supposed the portio intermedia to give a branch which united with the vestibular nerve, while the remaining portion passed itself into the facial.\nMore recently, the anatomy of the distribution and connections of this nerve seems to have been fully made out by Morganti in an elaborate monograph on the Geniculate ganglion* ; which is, I believe, chiefly known in this country through the medium of an excellent analysis contained in one of Mr. Paget\u2019s Reports.^ By careful dissection of the nerves, which he had previously hardened in nitric acid, Morganti' succeeded in unravelling their filaments ; and thus in separating th\u00e8 portio intermedia from the facial and vestibular nerves to a much greater extent than had hitherto been accomplished. The general result of this process was, that many of the so-called anastomoses were shown to be mere relations of propinquity, due to an intricate entanglement, but not implying any real junction or interchange of fibres.\nIn the human subject. \u2014 The portio intermedia (fig. 405, b), shortly after its origin, and\nFig. 405.\na- b c\nDiagram of the Portio intermedia and its branches. (After Morganti.')\n* Op. cit.\nt Report on the Progress of Human Anatomy and Physiology in the year 1844-5. British and Foreign Medical Review.","page":548},{"file":"p0549.txt","language":"en","ocr_en":"549\nSEVENTH PAIR OF NERVES.\nwhile lying closely by the side of the vestibular branch of the auditory nerve (c), gives off a filament (d), which passes towards it. Before joining with it, however, a similarly small branch which comes off from the latter nerve, unites with that previously given from the portio intermedia, and the common trunk thus formed passes into and is lost in the vestibular nerve.\nThe intermediate nerve next emits two small filaments (e), which join the portio dura, and cannot be satisfactorily traced through its trunk.\nThe description is now complicated by the introduction of a large branch of the facial (f) which emerges from it to take a spiral course around the portio intermedia ; and which, after running with it for some distance, returns to the facial at a lower point than that from which it set out.\nSetting aside this fictitious junction, the whole of the portio intermedia, after the giving off of the facial and auditory branches, was traced into the genuform intumescence : this, it will be recollected, is seated on the first bend of the facial in the Fallopian canal, and close to the hiatus of the same name.\nThe nature of this intumescence is the next question to which the description directs itself, and is perhaps even more important than the preceding dissections. The appearances of this swelling, and its reddish-grey colour, had long given rise to conjectures of its ganglionic nature. Many anatomists, indeed, have affirmed its identity with the true ganglions. By others, however, it has been somewhat obscurely described as intermediate in structure between a ganglion and a gangli-form enlargement: a description which can only be understood as indicating their doubt of its ganglionic character, since the supposition of such a gradation of texture is perfectly gratuitous. And others have altogether denied its ganglionic characters ; attributing its colour to the minute vessels which pass through the hiatus Fallopii to the facial nerve and internal ear, and explaining the appearance of enlargement or intumescence by the divergence of the fibres of the superficial petrosal nerve where it joins the facial.\nWith the question of the ganglionic structure of this body has necessarily been mixed up that of the course taken by the nerves which arise from it, and their relation to the facial. Indeed, the negative side of the argument\u2014the denial of the ganglion \u2014perhaps requires its advocates to explain the real nature of the swelling, and to show the arrangement of its supposed constituent nerve-fibres. But in the present day at least, the affirmative of the question may be justifiably reduced to the detection, in the so-called ganglion, of the globular vesicles which are essential to the structure of a nervous centre.\nJt is singular that for a considerable time this simple method of settling the disputed nature of the intumescence should either have escaped notice or failed to afford any satisfactory results : the latter seems to have been\nsometimes the case ; but more frequently, perhaps, this method of proof or disproof was overlooked. The discovery of the ganglion corpuscles, and thus the establishment of its ganglionic nature, belongs to Morganti. He describes it as consisting of meshes or reticulations of nerves, the intervals of which are filled by a yellowish ash-coloured substance. In the latter, he states himself to have verified the existence of these bodies.\nThe essential part of this description I am able to confirm. It appears difficult to obtain specimens from the human subject in a state sufficiently fresh to observe these delicate and easily decomposed corpuscles. In the lower animals, however, this difficulty is no longer met with ; and many of them present the additional advantage of a much less dense neurilemma than that which is present in the human structure. After removing the brain of the sheep, the ganglion may thus be easily exposed and removed, preferably with the nerves still attached to it. Cutting off the attached extremities of these, and very gently and imperfectly tearing up the ganglion which remains, completes the preparation of the specimen. Under these circumstances, the corpuscles of the grey matter are readily visible. They are of an oval or roundish shape, and of a very large size, which amounts in the average to about the 1 -200th of an inch. In the uninjured parts of the specimen, they appear to be disposed with considerable regularity, each being in contact with several others by a part of its surface. On a rough calculation, the ganglion contains about three or four hundred of these corpuscles. The contents of the corpuscles are of the ordinary kind. A nucleus occupies some portion of their inner surface, and a large quantity of the usual granular substance fills up the remainder of their interior. Most of them also contain a quantity of pigment towards one extremity of their ovoid cell-cavity. This is disposed as a dark brown mass of an oval form, and some of these masses, when seen isolated by the accidental rupture of their containing vesicles, have exhibited a defined and sharp outline,, which induces me to suspect their inclusion in a cell membrane, separating them from the rest of the contents of the vesicle. Rarely there are appearances of short processes from these vesicles. Nerve tubules in rather sparing quantity are found in contact with these large cells, mostly occupying their interstices, or coiled around their circumference ; and the periphery of the ganglion itself is surrounded by a kind of layer of them : these appearances, however, seem distinctly traceable to the mechanical violence employed in the examination, which forces the tubes into the situations of least pressure ; and one cannot, therefore, regard them as affording the least insight into the mode in which the nerves are arranged with respect to the vesicles.\nFrom this ganglion emerge, or rather to it are attached, the following branches:\u2014!, and 2. The superficial petrosal nerves, the greater of which (fig. 405, h) passes to the n n 3","page":549},{"file":"p0550.txt","language":"en","ocr_en":"550\nSEVENTH PAIR OF NERVES.\nspheno-palatine, and the lesser (i) to the otic ganglion : the first of these Morganti has depicted receiving a filament (k), which comes from the facial, and in its course to the petrosal nerve passes over the ganglion without joining it. The second or lesser of the two appears to be derived solely from the ganglion. 3. A large branch (m) which forms the great bulk of the chorda tympani ; but, in order to this, is also joined by one or two filaments (\u00ab) from the facial nerve, which accompanies it in the Fallopian canal. 4. Branches (/) which passing downwards are lost in the trunk of the portio dura.\nThe annexed diagram, {fig. 405.) with the letters attached to it, will assist the reader in following this otherwise intricate description. It is taken from a drawing by Morganti in the essay referred to ; but it has been reduced in size and simplified, so as better to allow of its introduction here.\nThe same author has examined into the comparative anatomy of the ganglion and the nerves connected with it in many of the other mammalia, as the dog, calf, lamb, mule, and dormouse.\nThe general results of these examinations abundantly verify his description of the arrangement in the human subject. Indeed, these animals offer by far the most favourable subjects for exemplifying the truth of the preceding description, being, as Morganti remarks, natural preparations of these parts. Not only is the dense and intimate^ adherent sheath of fibrous tissue, which is present in man, much looser in the ganglion and nerves of these animals, but the position of this body with respect to the nerve is considerably altered. The much less marked anterior bend of their portio dura occurs at some little distance from the hiatus Fallopii ; and the ganglion, which is in immediate proximity to this aperture, is thus no longer geniculate in its position, being removed from the knee of the facial. Hence it is, as it were, out of the way of the facial branches, and ceases to be entangled amongst them, as in the human subject.\nThe author of this article can bear testimony to the accuracy of these statements; indeed, any one may easily verify them for himself, in most of these animals, with scarcely more trouble than removing the brain and osseous roof of the Fallopian canal, and then stripping off the comparatively lax neurilemma from the subjacent ganglion and nerves. The accompanying sketch {fig. 406.) was taken from the left side of a sheep\u2019s head. With as little artificial separation as possible, it represents the arrangement of the ganglion and nerves in situ, especially the manner in which the trunk of the portio intermedia crosses the facial nerve without joining it, and the apposition or proximity, without mingling, of the ganglion and the latter nerve.\nThe varieties of arrangement which obtain in the different animals whose nerves Morganti examined, are chiefly, as might be expected, differences in the degree of inter-\nlacement of the adjacent nerves. In particular, that of the portio intermedia with the\nFig. 406.\nAuditory, Facial, and Intermediate Nerves of a Sheep\nas seen in situ. Magnified about 2^ diameters.\na, portio dura; b, portio intermedia; c, portio mollis ; e, origin of the superficial petrosal nerves ; f, chorda tympani ; g, geniculate ganglion.\nvestibular nerve is sometimes so complete and intricate, as to render it in such instances difficult to ascertain from their examination only, whether the former of these nerves gives branches to the latter, or, vice versa, this to that. In the mule, he exhibits a filament from the facial to the ganglion ; but thinks this a possible restitution of one or both of the two previously given to it by the portio intermedia.\nThe general anatomical conclusion to be drawn from these details is, that the facial nerve\u2014as implying in this term both the portio dura and the portio intermedia\u2014 arises by two roots. Upon the smaller of these a ganglion is formed, while the latter is entirely devoid of such a structure. The branches of the facial nerve in the Fallopian canal are mixed nerves, being formed partly by filaments from the ganglion ; partly also by filaments from the aganglionic root ; the latter being in considerably lesser numbers. And the trunk of the facial itself, beyond the ganglion, is also a mixed nerve, since, although by far the greater part of its bulk consists of fibres from the greater root, yet it also contains one or two filaments which come from the ganglion. The analogy of this arrangement to that of the spinal nerves is sufficiently obvious, and will be hereafter again referred to.\nIt deserves to be mentioned in this place, that many other accounts of the arrangement of these nerves might easily have been added from various authors, but that all of them are more or less at variance, both with the above description by Morganti, and with each other. It has seemed fit, however, to assign these a very subordinate position in the present short article, since the verification of a ganglion belonging exclusively to the portio intermedia includes not only the denial, but I think we may add the disproof, of many of these descriptions. So far as our knowledge of the structure of ganglia at present extends, and whether the late brilliant researches of Rudolph Wagner* apply universally or not, we are at least justified in viewing with great\n* Handw\u00f6rterbuch der Physiologie. Siebenzehnte Lieferung. Artikel \u201c Sympathischer Nerv Ganglienstruktur und Nervenendigung.\u201d","page":550},{"file":"p0551.txt","language":"en","ocr_en":"551\nSEVENTH PAIR OF NERVES.\nincredulity any account of the unaltered passage of a nerve through a ganglion, as viewed by the unassisted eye ; and, in the particular instance before us, the microscope disproves this supposition. So, also, concerning the various theories of the derivation of the superficial petrosal nerves which have been set forth as based on dissections. Let it be granted that there are two ganglia,\u2014the sphenopalatine and the geniculate, \u2014 which are united by an intervening nervous cox'd: in such a case, I cannot see how any merely anatomical skill would enable one to predicate a definite direction as taken by the connecting nerve. Indeed, any statement of this kind really amounts to asserting a special direction or quality of the nervous force, and to the affirmation or denial of such a view, the scalpel affords no assistance.\nThe unravelling of the nerves themselves, even as performed in the above dissections, requires, perhaps, to be received with considerable caution ; and that natural separation or simplification which is afforded by their comparative anatomy must be regarded as vastly increasing the value of the results obtained. The chorda tympani affords a good instance of the conflicting results of these dissections, when unaided by this latter method of inquiry. Some have considered, with H. Cloquet and Longet, that, after remaining a short time in contact with the gustatory or lingual branch of the fifth, the whole of this nerve passes away from it, to form one of the roots of the submaxillary ganglion. Others have described it as only giving a filament to this ganglion, and uniting itself by the remainder of its bulk with the branch of the fifth ; while others have failed to detect any direct transition of the chorda tympani into the ganglion, but, on the contrary, have found the two nerves inseparably mixed up below the situation of their visible junction. And more recently it has been traced by Guarini* to the lingualis muscle. On general grounds, the first of these notions is liable to much objection, since it seems singular that a nerve so far removed from the facial as the chorda tympani is at the base of the. skull, should be involved in such an accidental proximity as this would make it, or should run so closely to the gustatory without any interchange of fibres. Again, the total passage of the nerve to the ganglion appears very improbable, when the relative size of the entering and emerging branches is considered, \u2014 that is, on comparing the bulk of the chorda tympani with that of the two or three filaments which join the ganglion, it may be seen that the former is larger than all of them together. This is especially the case in some of the lower animals, as the dog ; in whom the submaxillary ganglion and its roots from the cerebral nerves are so greatly reduced in size as to be scarcely visibfe to the naked eye, while the chorda tympani continues a comparatively large branch. Rut these general\nobjections will not apply to the supposition of a partial connection of the chorda tympani with the submaxillary ganglion, and the question must accordingly still remain in doubt.\nPhysiology of the seventh nerve. \u2014 The functions sustained by the auditory nerve are recognised with sufficient certainty. The anatomy of its distribution, its variations in the different classes of the animal kingdom, and the results of experiment or disease affecting its structure, all unite to indicate.it as the nerve which, specially adapted at its periphery in the organ of hearing to receive impressions from the vibrations of the external air, conveys them to the brain, and by exciting corresponding impressions there, gives rise to the production of a sensation which we term a sound. For the further details of its function, reference is made to the article Hearing.\nThe facial nerve.\u2014 It has been seen from the preceding description, that the facial nerve is distributed almost exclusively to muscular structures ; and, although these are very numerous, yet they all admit of being reduced to one class, viz. the muscles of the face. A further subdivision would next separate them into several groups, which serve to enlarge or diminish the size of the various apertures by which impressions are admitted to the organs of the special senses, as the eye, ear, nose, and tongue. But these orifices are also the pathways of food and air, so that the muscles which regulate their size have thus far an influence on the functions of respiration and digestion. In man, they fulfil the further purpose of organs of expression ; their various and complicated adjustments conveying, for the most part, a tolerable index of the passions or emotions of the presiding mind.\nThis prominently muscular distribution of the facial would lead us to expect \u00e0 priori that the nerve was chiefly motor in its function ; and, if we turn from its anatomy in the human subject to its varieties of arrangement and appearance in the animal kingdom, this view will be abundantly confirmed. Not only is its peripheric distribution almost exclusively muscular, and in connection with the same facial set of muscles, but it also experiences a development which is co-equal, with that of these organs, increasing with their augmented development, or disappearing with their suppression. Thus, in Fishes, the facial scarcely exists as a separate nerve. In Reptiles and Birds, its small size corresponds with the bony and immobile state of the face. In the Mammalia, it becomes much more considerable, and both the nerve and muscles experience various degrees of augmentation. Thus, in the monkeys it attains a large size, in accordance with the number and magnitude of the facial muscles generally ; and the trunk of the elephant, and the muscular apparatus connected with the blowholes of Cetaceans, are supplied by large branches from this nerve, which here experiences a partial development, to meet the special exi-N N 4\nAnnali di Medicirla. Maggio, 1842.","page":551},{"file":"p0552.txt","language":"en","ocr_en":"SEVENTH PAIR OF NERVES.\ngencies of the case. In man, the nerve attains the maximum of general development.\nExperiment also confirms the testimony afforded by the human and comparative anatomy of the facial nerve : indeed, the results afforded by this method of enquiry first led Sir Charles Bell* to the discovery of its function. On cutting across the trunk of the nerve, he found that the whole side of the face on which it was divided had completely lost the power of movement, while its sensibility remained unimpaired. His experiments have since been frequently repeated, and invariably with the same results.\nThe over-excitement of the nerve affords evidence of its motor function, equally with the destruction of its continuity. Thus, galvanism of the distal extremity of the cut nerve at once sets up convulsive movements in the muscles to which it is distributed.\nThe paralysis produced by section includes all those muscles which the facial has been previously described to supply ; but the muscles of the jaw, which are furnished with nerves from the inferior maxillary division of the fifth, are still free to execute their contractions, and hence the movements of the jaw continue. But although these are still carried on, yet the act of mastication as a whole is rendered very imperfect ; since this not only requires the apposition and trituration of the teeth upon each other, but also demands accessory though subordinate movements of the neighbouring lips and cheek, and the section of the facial nerve distributed to these parts render these adjuvant movements impossible. In such cases an imperfect mastication may indeed be seen to take place ; but the cheek and lips, having lost their contractility, instead of pressing in the food towards the teeth, and submitting it again and again to their action, allow it constantly and gradually to accumulate in this flaccid and yielding pouch ; or permit it to fall out of the anterior opening in the mouth. In this instance, experiment throws a reflected light upon descriptive anatomy. The buccinator muscle, which forms the greater part of the fleshy parietes of the cheek, was previously mentioned as receiving branches from both the facial and inferior maxillary nerves ; and were we to confide altogether in the appearances seen in dissecting these nerves in the human subject f, we might perhaps justifiably regard them as sharing between them the supplying of the muscle. But the paralysis of the buccinator, which is always present in those instances where the facial nerve has suffered division, points distinctly enough to the latter as at least taking the more considerable and important part of the two ; while\n* Exposition of the Natural System of the Nerves of the Human Body. London, 1824.\nf The lesser development of the facial muscles of the lower animals allows the distribution of the small buccal nerve to be more easily traced. Thus, in the dog, the two small filaments which form it pass, as is evident on dissection, almost exclusively to the mucous membrane and buccal glands.\nthe failure of the galvanic stimulus to affect the muscle through the buccal nerve, indicates that the filaments of the facial are in all probability the only motor nerves which are distributed to it.\nMany of those cases of paralysed facial nerve, which occur in the human subject as the effect of disease involving their structure, approximate closely to the results obtained by an artificial division of the nerve in animals ; but in consequence of the much more expressive character of the human countenance in the normal state, the deviations produced are even of a more striking appearance. One half of the face forms a perfect blank, its muscles hanging passively from the subjacent structures ; while the movements of the opposite side are distorted by the absence of their proper antagonist motions, and are exaggerated in appearance by the contrast.\nIn the experiments above mentioned, Sir Charles Bell found that immediately on dividing the nerve the muscular aperture of the nostril, which had previously been subject to an alternate dilatation and contraction during the periods of inspiration and expiration respectively, suddenly lost this movement. He has termed the portio dura the respiratory nerve of the face ; since it presides over these and other motions of the facial muscles, which are developed independently of the will, and in answer to the necessities of respiration.\nThe section of the facial nerve indirectly affects the sense of smell. This fact was also first pointed out by Sir Charles Bell, and has since been confirmed by many other observers. Under these circumstances, the power of discerning strong odors, as tobacco and ammonia, appears to be much diminished on the affected side, although scarcely absolutely lost. This loss of smell has been ascribed to the absence of two causes greatly conducive to the exercise of this faculty in health. The muscular contraction of the nostril which accompanied the effort of snuffing effects a considerable narrowing of the aperture ; and in the deep inspiration which accompanies the act, the rapidity of the entering current of air is thus greatly augmented, and in this greater velocity is implied an increased contact of the odorous vapour with the sensitive surface. Besides this, the direction of the current of air seems to be somewhat altered ; the muscles, tending much more to constrict the posterior than the anterior parts of the orifice, appear to direct the current more upwards or anteriorly than in the ordinary inspiration. The mechanical nature of the action has been illustrated by Diday *, who has shown that dilatation of the nostrils by a glass tube, through which the air may be respired, equally pre -vents the perfect exercise of the olfactory sense; and Longet^onfirms his experiments. The effect of division of the portio dura on\n* Gazette Medicale, 1838. Memoire sur les appareils musculaires annex\u00e9s aux organes des sens.","page":552},{"file":"p0553.txt","language":"en","ocr_en":"SEVENTH PAIR OF NERVES.\n553\nthe eye is still more important. There is complete inability to close the eyelids of the affected side. This permanently open state is due to the action of the levator palpebr\u00e6, unopposed by the paralysed orbicularis palpebrarum ; and the eye itself, no longer preserved from the contact of foreign bodies, or swept over by the conjunctiva which lines the eyelids, is often irritated into inflammation. The hazy vision which accompanies this condition is partly attributable to this cause ; but more frequently depends on the imperfect removal of the lachrymal secretion, which becomes irregularly diffused in a more or less solid or dried state over the globe. The general relaxation of the orbicularis perhaps aids this, and it has also the effect of altering the position of the puncta lachrymalia, and thus preventing the natural exit of the secretion, which is sometimes poured down the face. But these effects are on the whole rarely so complete as is above stated ; the aperture between the eyelids is usually small, and movements of the globe of the eye are to some extent substituted for those of the lids ; so that the general results offer the most marked contrast to the rapid disorganization which follows the section of the fifth nerve which forms the sensitive supply of these parts.\nBesides the influence of the facial nerve on mastication, as shown by the result of its paralysis or artificial division ; the sense of taste appears to be considerably impaired on the corresponding side. This fact has been well illustrated by M. Claude Bernard *, who has collected nine or ten cases of this kind. The manner in which the sense is affected seems to vary. Thus, he describes it as an impairment, in which the most sapid substances failed to excite their ordinary impressions, and are only perceived after a considerable interval of time. Professor Roux has. left a recital of his sensations during a rheumatic facial hemiplegia ; and in his description, which Longet quotes j', he mentions that everything on the affected side tasted strongly metallic ; whence it would appear that this diminution of taste is sometimes substituted by a perversion or depravation of the function.\nAnd M. Bernard has conclusively shown that the chorda tympani is the immediate instrument of the change. He has adduced instances of paralysis from experiments, in which the facial nerve being divided above the point where this nerve diverges, the taste was constantly impaired ; while in the facial paralysis due to disease of the nerve below its origin, the sense was unaffected.\nIn connexion with these facts may be mentioned the motor function of the chorda tympani. It has been previously stated that, among other courses ascribed to this nerve after its union with the gustatory, Guarini has succeeded in tracing its filaments to the\n* Archives Generales de la Medicine, 1843, 1844.\nf Op. cit. tom. ii. p. 465.\nlingualis muscle. But in addition to this, he has adduced experimental evidence of a much more conclusive character. He found that galvanising the fifth, ninth, and facial nerves affected the muscles of the tongue in a very different manner. When the sensitive nerve was stimulated, the tongue remained without movement ; but in the case of the ninth and facial, an upward and downward movement was perceptible. When the hypoglossal was galvanised, a backward and forward motion was added to this common movement; while on stimulating the facial nerve, the middle tract of the tongue, which had remained tranquil in the previous experiments, was agitated in a vermiform manner. This latter movement was instantly annihilated by section of the chorda tympani. The region which it occupied was that of the lingualis muscle, and to it he traced some branches of the nerve : while the upward and downward movement belonged to the styloglossus. The cause of the affection of the taste is very imperfectly understood ; since, in the case of the tongue, it seems difficult to connect such an impairment of the special sense with any mere loss of motion. Bernard has, however, offered such an explanation ; in which, as a preliminary, he supposes a vermiform movement like that observed to be necessary to taste, and that it acts by increasing the contact of the papillae of the tongue with the sapid particles. And although this is sufficiently unlikely, yet it is advisable to recollect that, unless guided by experience, we might have asserted the same improbability in the instance of smell; while this sense has been seen to experience an equal impairment, and in a method very similar to this which Bernard has supposed :\u2014viz. by a diminution of effective contact between the object of the special sense and the distribution of its nerve, which contact is itself in part the result of the contractions of certain muscles, supplied by branches of the facial.\nThe mixed nature of the chorda tympani, as laid down by Morganti, may perhaps explain these effects in a different manner; by suggesting that the paralysis of this nerve involves the loss of some of the sentient as well as motor filaments distributed to the tongue. And the varieties in the nature of the affection which were indicated above, perhaps render this explanation a more probable one.\nA connection has also been traced between the paralysis of the portio dura and an abnormal state of the soft palate: \u2014 the curtain of the palate itself being somewhat relaxed, while the uvula is drawn towards the unaffected side. In a great number of facial palsies, however, this deviation is absent. But although materials on this point are yet somewhat few, it may be safely stated that its presence or absence varies according to the seat of the disease causing the paralysis : if above the geniculate ganglion, the deviation appears pretty constantly present ; if below, it is absent. The light which ex-\ni","page":553},{"file":"p0554.txt","language":"en","ocr_en":"554?\nSEVENTH PAIR OF NERVES.\np\u00e9riment affords is somewhat uncertain and conflicting. Mechanical irritation of the root of the facial nerve in various animals has failed to excite contractions of the muscles of the palate, both with Valentin* and Hein.-}-The stimulus of galvanism has also acted irregularly and variably, being sometimes followed by contractions, sometimes not. It is, on the whole, difficult to avoid coming to the conclusion that the facial nerve is intimately associated with the movements of the palate by its greater petrosal branch : but the actual transmission of its uninterrupted filaments through the spheno-palatine ganglion is, on anatomical grounds, exceedingly doubtful. And the experiments above mentioned, together with others in which Hein found that its division did not affect pre-existing movements from other nervous sources, render the term \u201c motor nerve \u201d clearly an inapplicable name.\nConcerning the influence of the facial nerve on hearing, little is known at present. Longet, in quoting the above case of M. Roux, in which comparatively faint sounds were painfully distinct, has given a very probable and ingenious explanation of the fact, by pointing the derivation of the nerve to the tensor tympani from the otic ganglion, which is itself associated with the geniculate ganglion and facial nerve. Regarding this muscle as the regulator of the acoustic drum, and the tension of this as the means of moderating excessive stimulus, just as the iris does in the eye, he shows the probability that the parai) sis of the tensor in this manner deprives the ear of an important protection, and increases the loudness of the sound \u2019\u2019eceived.\nIt has thus been deduced that the facial is chiefly a nerve of motion ; or, in other words, that by its central and peripheral organization it is adapted to determine the contraction of the facial muscles. It has next to be considered whether it is exclusively motor, or whether, on the contrary, it contains a certain proportion of nervous filaments, the office of which is the production of sensations.\nThe highly sensitive integument which forms the surface of the face, evidently receives its nervous supply solely from the different divisions of the fifth ; and the anatomy of the distribution of these branches is confirmed by comparing the results which are obtained by artificial section of the facial and fifth nerves. In the case of the divided portio dura, it was previously mentioned, that while motion is lost, sensibility is unaffected ; while in the common instance of the divided fifth, mobility remains, but the sensibility of this surface completely vanishes, and no expression of pain can be obtained even by cauterising large portions of the integuments.\nThe facial is thus excluded from all share in the tactile sensibility of this surface ; yet it by no means follows that the nerve itself is wholly insensible. On the contrary, the ex-\n* Lehrbuch der Physiologie, B. ii. S. 673.\nf Muller\u2019s Archiv. 1844. Heft. 3, 4.\nperiments of most physiologists from the time of Bell agree in verifying the fact of its sensibility ; as shown by the expressions of pain which are called forth on mechanically irritating the nerve in the living animal. Thus, pinching the trunk of the facial, or any of its larger branches, or the act of section itself, have been constantly found to be accompanied by the most unequivocal indications of suffering.\nFrom the evidence above stated, it is manifest that the sensory filaments which we must suppose the trunk of the facial to contain, are not distributed to the cutaneous surface of the face. But although the skin is the chief organ of common sensation, it is by no means the only seat of the function : a variable but necessary share is possessed by the whole body, and accomplishes the general purpose of protection, perhaps also confers the muscular sense. Thus, by means of sensation, the injury of any particular part determines the occurrence of pain which is referred to that situation ; and in this manner attention is directed to the seat of injury, and its duration or increase is prevented by a voluntary act. And it is probable that the sensitive branches which accompany the portio dura are of this kind ; branches which, although very different in function, travel with the motor nerve, because they experience a distribution in its immediate neighbourhood. Indeed it is perhaps not unlikely that some of the sensory filaments which are included in the facial may bear a protective relation to this important nerve itself, possibly by a virtual distribution among its fibres : \u2014 a notion which would thus far approximate to the supposed \u201c nervi nervorum \u201d of the old authors.\nBut although the sensibility of the facial nerve is well ascertained, the origin or immediate cause of this endowment is still a matter of considerable dispute. The numerous views adopted by different authors offer many slighter modifications, but they are all reducible to two chief theories. One of these considers that the facial nerve is insensible at its origin from the brain ; and that whatever amount of sensibility it subsequently exhibits is due to foreign filaments, which come from the acknowledged sensitive nerves of the fifth and pneumogastric ; and which, joining the portio dura in different parts of its course, accompany it beyond these points included in its substance. The other regards the facial nerve as arising by two roots, whereof the larger is motor, the smaller sensitive ; and that the sensibility of the nerve as a whole is the result of its double constitution, and is effected by its own sensory filaments.\nEach of these theories has received the sanction of distinguished anatomists. Thus, amongst many others, the first has obtained the support of Magendie, Cruveilhier, Eschricht, Lund, &c. ; while the latter numbers amongst its advocates, Arnold, Bischoff, Goedechens, Barthold, and, more lately, Morganti.\nThe dispute scarcely involves the function","page":554},{"file":"p0555.txt","language":"en","ocr_en":"SEVENTH PAIR OF NERVES.\t555\nof the portio dura in that larger sense, in which we generally use this word of nerves ; and hence the changes effected by disease afford very little aid to the settlement of the question. The inquiry therefore limits itself to a judgment on the two remaining kinds of evidence : firstly, the results of experiment ; and secondly, the anatomical appearances. With this latter means of proof, a third is intimately associated in the present instance ; viz. the analogies offered by the structure of the facial to other nerves, of which the functions are better ascertained. These analogies, where present, will argue a similarity of function ; and in a degree of probability varying with the degree of the resemblance.\nOn the supposition that the sensory filaments are borrowed from neighbouring nerves, the very numerous junctions of the facial and fifth would naturally point to the latter as constituting one of the most probable and important sources. There are two ways of instituting the question experimentally. If these filaments come from this nerve, the destruction of its continuity will annihilate the sensibility alike of the facial and itself. Again, if the portio dura be insensible until joined by these branches of the fifth, irritation or section of the former nerve, previous to the point of junction, ought to be unattended by pain. In both these methods, the fifth is functionally separated from the facial ; but in the second instance, the natural isolation of this nerve behind the situations where the fifth joins it, supplies the place of the artificial isolation practised in the first. And in both the continuance of sensibility would imply that the portio dura possessed inherent sensitive fibres.\nThe division of the fifth nerve within \u00c7he skull, or close to its origin from the encephalon, has been attended with insensibility of the facial, in the hands of Magendie*, Es-chricht, Lund f, and LongetJ ; and I am not aware of any such experiments which have contradicted their statements. The latter author states that, under these circumstances, the insensibility of the portio dura is perfect ; but Lund and Eschricht, although they seem to deduce the same conclusion that he does, viz. that the sensibility of the facial nerve is entirely due to its anastomoses with the fifth, \u2014yet, nevertheless, distinctly state that in their experiments the insensibility produced extended only from the ear forwards ; while behind this situation the portio dura still evinced a well-marked sensibility. Apparently, Longet would explain this contradiction by supposing that the nerve behind the ear, which they found to be still sensible, was an ascending filament of the cervical plexus ; but it seems very unlikely that they should confound the facial trunk with so very small a twig as one of these cervical branches would be. It must\n* Le\u00e7ons sur les Fonctions du Syst\u00e8me Nerveux, torn. ii. p. 181.\nf Dictionnaire des Sciences M\u00e9dic., Journal Com-pl\u00e9m, tom. xxvi. p. 204.\nX Loc. cit.\nbe observed that the results afforded by section of the fifth are only valid when the whole of the nerve has been divided, since in any other case there is a possibility that the sensibility of the facial, which remains after the operation, is due to the reception of filaments from the uncut branches.\nThese anatomical considerations apply even more forcibly to the second series of experiments. Thus, in some of them, conclusions are sought to be drawn from the observed sensibility of the larger branches of the nerve in the face; but the numerous anastomoses with the fifth, of which mention has previously been made, and especially that large union with the auriculo-temporal nerve of its third division, immediately in front of the ear, invalidate all these results.\nSimilar contradictory evidence obtains concerning the sensibility of the facial at its emergence from the skull, or behind its more visible junctions with the fifth. Thus, Valentin regards it as insensible in this place, while the experiments of Longet, Morganti (and probably Eschricht and Lund, as above stated), induce them to maintain the opposite opinion. So that, perhaps, on the whole, the balance of evidence inclines towards the statement that the irritation of the facial nerve at the stylo-mastoid foramen is attended with expressions of pain, and, therefore, that the nerve is possessed of sensibility at this place.\nThe reception of this fact considerably narrows the question ; since the only branches connected with the facial above this point are, the greater and lesser superficial petrosal nerves, and the auricular filament of the pneu-mogastric. But Morganti has laid bare the chorda tympani in the tympanum, and has proved its sensibility to irritation. And this nerve, it will be recollected, comes* from the portio dura at a point above its junction with the auricular filament; and since the latter is thus not essential to the sensibility of this branch of the facial, so in all probability it is not necessary to the sensibility of this trunk itself. Thus the superficial petrosal nerves only remain ; and many who consider one or both of these to join the facial, explain the sensibility of the nerve in the Fallopian canal by supposing that they convey to it branches of the second or third division of the fifth, which pass through the spheno-palatine and otic ganglia respectively. But, as has been previously stated, anatomy fails to recognise such a direct passage to the facial ; and, on the contrary, by showing the unequivocally ganglionic nature of the genuform intumescence, renders it highly improbable. And on physiological grounds, it seems difficult to imagine that a nerve or nerves should pass unchanged through two successive nervous\n* Some have supposed the chorda tympani to pass from the gustatory to the facial nerve, conveying sensitive fibres to it. But numerous arguments, especially its anatomy and function as above mentioned, combine to render this supposition quite untenable.","page":555},{"file":"p0556.txt","language":"en","ocr_en":"656\nSHELL.\ncentres, of which they form such large and important roots : while, allowing them to be affected in their functions, we are at least not justified in calling them \u201c sensitive branches of the fifth.\u201d\nBy this elision of one sensitive anastomosis after another, sensibility still remaining, we have been led, in a retrograde course, to the ganglion at the hiatus Fallopii : at and above this point the evidence afforded by experiment fails us.\nMagendie* states himself to have succeeded, in one instance, in exposing the facial nerve within the skull, or where it enters the auditory meatus ; and adds that it was insensible to irritation. But the experiment stands alone, and it appears doubtful whether the portio intermedia was included in the irritation.\nBut the anatomical discoveries of Morganti may somewhat supply the deficiency of direct evidence. He has pointed out the complete analogy of the facial to a spinal nerve ; and hence deduces the probability, that the portio intermedia, which exclusively forms the geniculate ganglion, is, like the posterior or gan-gliform root of the spinal nerve, the source of sensitive fibres\u2019to the compound nerve.\nThe observed insensibility of the facial after section of the fifth militates strongly against this view. But it will be recollected that although affirmed by some, it has been denied by others. And even granting it to be as complete as Longet states it, yet possibly it would constitute a less conclusive objection than might at first appear. For when we consider the violent nervous shock which division of the important trifacial must produce on the parts in the immediate neighbourhood of its origin, and the close proximity of the two nerves at their roots, we are perhaps justified in considering the result an insufficient testimony to their more immediate connection. A comparison of the lesion and symptoms in many cases of cerebral hemorrhage would almost parallel the occur-' rences of such an an\u00e6sthesia ; while, in such an instance, a direct continuity would scarcely be admitted.\nBut even granting that the facial nerve, as thus constituted, possesses an inherent sensibility, it is still probable, from its numerous anastomoses, both with the fifth and with the cervical nerves, that it subsequently receives many additional sensory filaments. These junctions differ from a plexus like the cervical, or brachial, in the fact that, in place of forming communications between the mixed nerves of different segments of the body, they connect nerves of different endowments. The exchange appears to be at the expense of the sensitive nerve ; that is, more filaments seem to pass from the fifth to the facial than from the latter to the former. The amount of these filaments given to the different branches of the seventh is said to differ : thus, Longet affirms the insensibility of the \u201c mentonnier,\u201d or supra-maxillary portion.\n* Loc. cit.\nLittle can here be said of the more minute ramifications of Morganti\u2019s theory.* But nothing that is known at present, either of the facial generally, or of the chorda tympani, or superficial petrosal branches, is absolutely incompatible with his views. All of these branches, except the lesser petrosal, he shows to be mixed nerves : the experiments and observations above quoted tend to indicate all as more or less directly subservient to motion ; and in none are we able to deny the possibility of sensation. But the petrosal nerves would probably be likened to the branches which connect the roots of the spinal nerves to the sympathetic ganglia on the side of the spine ; and the obscure and uncertain results obtained by experiment on these filaments of the facial are closely analogous to the effects of similar experiments on the spinal nerves in connection with the sympathetic of the trunk. But the anomaly of the tensor tympani being apparently supplied solely from the sensitive portion of the facial nerve, is very much weakened by the physiological facts of the involuntary character of its movements, and the interposition of a second ganglion.\nThe more important effects of disease of the facial nerve have already been spoken of in treating of its functions. For its morbid anatomy, in which it offers no especial peculiarity, reference is made to the article Nerve.\nBibliography. See Nervous System.\n( William Brinton.)\nSHELL.\u2014This term is commonly employed to designate the hard envelopes in which the bodies and members of many animals belonging to the Radiated, Molluscous, and Articulated sub-kingdoms are enclosed. Generally speaking, it is applied to those only into whose composition mineral matter enters : thus, we speak of the shell of a Crustacean, whilst we do not give that appellation to the dermo-skeleton of an Insect or Myriapod. Still this rule is not strictly observed ; for there are many Crustacea and Mollusca which are commonly spoken of as possessing shells although these bodies are entirely destitute of calcareous matter, being as horny in their texture as the envelope of a beetle or a centipede. Among radiated animals, the class of Echinodermata is the only one in which shells are met with ; and these are by no means universally present throughout the group. In the molluscous series, we meet with shells in every class save the Tunicata ; all the animals of the class Conchifera, whether lamelli-branchiate or pallio-branchiate, being furnished with them ; a considerable proportion of Gasteropoda (all of them, it would seem, in the embryonic state) possessing them ;\n* The comparative anatomy of the geniculate ganglion seems to show that its position is much more closely related to the orifice of the bone than to the motor nerve. Is this any analogy to the similar close relation (to a more external aperture) of the ganglion on the posterior root of a spinal nerve ?","page":556},{"file":"p0557.txt","language":"en","ocr_en":"SHELL.\n557\nwhilst they are occasionally found in the delicate little Pteropoda, and in the comparatively gigantic Cephalopoda. In this last class, however, the shells are not unfrequently internal; an approach to this arrangement being seen in certain Gasteropoda and Pteropoda, in which the shells are covered-in by folds of the mantle, whilst really external to :he body. In the articulated series, the presence of a shelly covering, according to the usual acceptation of thq term, is more restricted. It is possessed by a few Annelida (e. g. Serpula, Spirorbis, &c.), whose shelly tubes so much resemble those of certain Mol-lusks as to be readily confounded with them. It is usually found, too, in the Cirrhopoda, (a class whose articulated character is now quite settled) ; and it is generally present in the Crustacea, although it is only in the larger and more highly developed forms of this class, that the shell is consolidated by mineral deposit, and really deserves the appellation.\nThe external configuration of the principal varieties of shelly covering having been sufficiently described under the several heads above referred to, it is not requisite here to revert to that subject ; our present purpose being to give an account of the intimate structure of shell, on which an entirely new light has been thrown by microscopical enquiries. The prevalent doctrine respecting the nature of shell, as expressed even by the most recent conchological writers, has been that it is not only extravascular, but completely inorganic, being composed of an exudation of calcareous particles, cemented together by animal glue. It may now, however, be stated as an ascertained fact, that shell always possesses a more or less distinct organic structure* ; this being in some instances of the character ofthat of the epidermis of higher animals, but in others having more resemblance to that of the dermis, or true skin. The nature of the organic structure is so entirely different in the Mollusca, Echinodermata, and Crustacea respectively, that a separate description is required for each ; indeed, even in the subordinate divisions of these groups very characteristic diversities are frequently observable; so that, as in the case of teeth, it is often possible\n* The idea that such would prove to be the case was expressed by the author of this article in the 2d edition of his \u201c Principles of General and Comparative Physiology \u201d (published in 1841), as follows :\u2014\u201c The dense calcareous shells of the Mollusca, and the thinner jointed envelopes of the Crustacea, have been commonly regarded as mere exudations of stony matter, mixed with an animal glue secreted from the membrane which answers to the true skin. The hard axes and sheaths of the Polypifera, however, have l\u00ffen also regarded in the same light; and yet, as will hereafter appear, these are unquestionably formed by the consolidation of what was once living tissue. From the analogy which the shells of Mollusca and Crustacea bear to the epidermic appendages of higher animals, there would seem reason to believe that the former, like the latter, have their origin in cells, and that these are afterwards hardened by the deposition of earthy matter in their interior.\u201d P. 33.\nto determine the family, sometimes the genus, and occasionally even the species, from the inspection of a minute fragment of a shell, as well fossil as recent ; whilst the degree of correspondence or difference in the intimate structure appears to be, in many groups, more valuable than any other single character as a basis for classification, because more indicative of the general organisation of the animal. Examples of both these applications will be presently given.\nMollusca.\u2014The shells of Mollusca may always be regarded as epidermic in their character ; being formed upon the surface of the mantle, which answers to the true skin of other animals. As might be anticipated from this description, they are essentially composed of cells, consolidated by a deposit of carbonate of lime in their interior ; but, as in other tissues, we frequently find that the original cellular organisation is obscured by subsequent changes, and we sometimes lose all traces of it. We shall first examine it in what may be considered its typical condition, which is most characteristically seen in certain bivalves.\nIf a small portion be broken away from the thin margin of the shell of any species of Pinna, (this margin being composed of the outer layer only, which projects beyond the inner), and it be placed without any preparation under a low magnifying power, it presents on each of its surfaces, when viewed by transmitted light, very much the appearance of a honeycomb ; whilst at the broken edge it exhibits an aspect which is evidently fibrous to the eye, but which, when examined under the miscroscope with reflected light, resembles that of an assemblage of basaltic columns. The shell is thus seen to be composed of a vast number of prisms, having a tolerably uniform size, and usually presenting an approach to the hexagonal shape. These are arranged perpendicularly (or nearly so) to the surface of the lamina of the shell ; so that its thickness is formed by their length, and its two surfaces by their extremities. A more satisfactory view of these prisms is obtained by grinding down a lamina until it possesses a high degree of transparency ; and it is then seen (fig. 407.) that the prisms themselves appear to be composed of a very homogeneous substance, but that they are separated by definite and strongly-marked lines of division. When such a lamina is submitted to the action of dilute acid, so as to dissolve away the carbonate of lime, a tolerably firm and consistent membrane is left, which exhibits the prismatic structure just as perfectly as did the original shell (fig. 408.) ; the hexagonal divisions being evidently the walls of cells resembling those of the pith or bark of a plant, in which the cells are frequently hexagonal prisms. In very thin natural laminae, the nuclei of the cells can often be plainly distinguished ; but we cannot expect to find these, when the two ends of the cells (at one of which they are generally situated) have been removed by grinding. By making a section of the shell perpendicularly to its surface, we obtain a view of the prisms cut","page":557},{"file":"p0558.txt","language":"en","ocr_en":"SHELL.\n558\nin the direction of their length (fig. 409.) ; and it is then seen that whilst many of them pass\nFig. 407.\nSection of the shell of Pinna parallel to the surface, showing prismatic cellular structure, cut transversely. Magnified 185 diameters.\ncontinuously from one surface of the layer to the other, some terminate in points midway.\nFig. 408,\nLamina of decalcified membrane of prismatic cellular structure, from shell of Pinna. Magnified 185 diameters.\nHence it happens that the number of the reticulations is smaller on the interior than on the exterior of the layer ; their size, on the contrary, being greater. The prisms are seen to be marked by delicate transverse striae, closely resembling those observable on the prisms of the enamel of teeth, to which this kind of shell-structure may be considered as bearing a very close resemblance, except as regards the mineralising ingredient. If a similar section be decalcified by dilute acid, the membranous residuum will exhibit the walls of the prismatic cells viewed longitudinally ; and these will be seen to be more or less regularly marked by the transverse striae just alluded to. It sometimes happens in recent, but still more commonly in fossil\nshells, that the decay of the animal membrane leaves the contained prisms without any con-\nFig. 409.\nVertical section of prismatic cellular structure, from external layer of shell of Unio occidens. Magnified 40 diameters.\nnecting medium; and being then quite isolated, they can be easily detached from one\nFig. 410.\nVertical section of cellular structure of Pinna ; at its lower part the membrane is splitting into thin layers. Magnified 74 diameters.\nanother without any fracture. A group of three such prisms, found in a fragment of chalk, is shown in fig. 411.: it is seen that these also exhibit transverse striae of a similar aspect. By submitting the edges of the membranous walls of the prismatic cells divided longitudinally (as in fig. 410.) to a high magnifying power, the cause of the transverse","page":558},{"file":"p0559.txt","language":"en","ocr_en":"SHELL.\n559\nstriation is seen to be a thickening of the cell- thickness of the shell is made up of the interwall in those situations ; which will of course nal or nacreous layer ; but a uniform stratum\nFig. 411.\nCalcareous prisms of the shell of Pinna ; from Chalk.\nproduce a corresponding series of indentations upon the contained prisms. This thickening seems best accounted for by supposing (as first suggested by Prof. Owen) that each long prismatic cell is made up by the coalescence of a pile of flat epidermic cells, the transverse striation marking their lines of junction ; and this view corresponds well with the fact that the shell-membrane not unfrequently shows a tendency to split into thin laminae along the lines of striation, as shown in the iower part offig. 410; whilst we occasionally meet with an excessively thin natural lamina, composed of flat pavement-like cells resembling those of the epithelium of serous membrane, lying between the thicker prismatic layers, with one of which it would have probably coalesced but for some accidental cause which preserved its distinctness. That the entire length of the prism is not formed at once, but that it is progressively lengthened and consolidated at its lower extremity, would appear also from the fact that where the shell presents a deep colour (as in Pinna nigrina) this colour is usually disposed in distinct strata, the outer portion of each layer being the part most deeply tinged, whilst the inner extremities of the prisms are almost colourless.\nThe prismatic arrangement of the carbonate of lime in the shells of Pinna and its allies has been long familiar to concholdgists ; but it has been usually regarded as the result of crystallisation. It is now, however! perfectly evident that the calcareous prisms a'e nothing else than casts of the interior of the prismatic cells; the form of which, however irregular, they constantly present ; whilst the markings of the membrane are faithfully transferred to the surface of the prism. Further, the prisms in a thick layer of shell frequentlyfpresent a decided curvature, which would not be the case if their form were due to crystallisation. Not unfrequently, moreover, they are altogether destitute of angular boundaries ; the large quantity of animal matter disposed between the contiguous cells giving them a rounded contour, as seen in fig. 412, and thus causing the calcareous casts of thejr interior to be cylindrical rather than prismatic.\nIt is only in a few families of Bivalves, however, that the cellular structure is seen in this very distinct form, or that it makes up a large part of the substance of the shell ; and these families are for the most part nearly allied to Pinna. In all the genera of the Margaritace\u0153, we find the external layer of the shell formed upon this plan, and of considerable thickness ; the internal layer being nacreous. In the Unionidee, on the contrary, nearly the whole\nFig. 412.\nLamina of outer layer of shell of Ostrea edulis, showing its cellular structure, with a large amount of intercellular substance. Magnified 250 diameters.\nof prismatic cellular substance is always found between the nacre and the periostracum. In the Ostrace\u00e6 the greater part of the shell is composed of a sub-nacreous substance, the successively-formed laminas of which have very little adhesion to each other ; but every one of these laminae is bordered at its free edge by a layer of the prismatic cellular substance, distinguished by its brownish-yellow colour: this structure presents itself again in the family Pandorid\u0153, which belongs to quite a different section of the class ; and it is curious to observe that the marked difference in the structure of the shells of Pandora and Lyonsia from that of the Anatinid\u00e6 and other neighbouring families, harmonises completely with the peculiar combination of characters presented by-the animals of these two genera.* In all the foregoing cases, a distinct cellulo-membranous residuum is left after the d\u00e9calcification of the prismatic substance by dilute acid ; and this is most tenacious and'substantial where, as in the Margaritace\u0153, there is no proper periostracum, \u2014 as if the horny matter which would have otherwise gone to form this investment had been diffused as an intercellular substance between the proper cell-walls.\nIn many other instances, a cellular arrangement is perfectly evident in sections of the shell ; and yet no corresponding structure can be distinctly seen in the delicate membrane left after d\u00e9calcification. In all such cases the animal basis bears but a very small proportion to the calcareous deposit, and the shell is usually extremely hard. A very characteristic example of this is presented by the outer layers of the shells of the genus Thracia and other Anatinid\u00e6. But there are numerous other cases, in which no traces of cellular structure can be detected in the fully-formed shell, and in which we can only be guided by analogy in\n* See Forbes and Hanley\u2019s British Mollusca, vol. i. pp. 207, 213.","page":559},{"file":"p0560.txt","language":"en","ocr_en":"560\tSHELL.\nassigning to therfi a similar origin with the preceding. We seem justified in doing so, however, by two considerations. In the first place, where the fully-formed shell is destitute of cellular arrangement, this may be frequently detected in the embryonic shell ; as the author is informed by Dr. Leidy of Philadelphia, who has carefully studied the embryology of many Mollusca. And secondly, there are certain shells which exhibit so complete and gradual a transition from adistinct cellular arrangement to an apparently homogenous structure, that we can scarcely doubt the common origin of both substances. This is particularly well seen in the common Mya arenana, a careful examination of which shell brings to light numerous interesting varieties of cellular organisation. Thus in jrcg.413. we see in one part of\nFig. 413.\nSection of shell of Mya arenaria, showing in one part distinct cellular partitions, with large nuclear spots ; whilst in another part of the same layer, the cell-boundaries become fainter, and then disappear altogether. Magnified 150 diameters.\nthe section a very distinct set of cell-boundaries, with a large nuclear spot in the centre of each cell ; whilst on the other side we observe that the cell-walls have completely disappeared,\u2014the nuclear spots, however, still remaining to mark the cellular origin of the substance. A little further on, these also might disappear, and thus all traces of the original organisation might be lost, though no reasonable doubt could be entertained as to its prior existence. A very curious variety of cell-structure is seen in the large hinge-tooth of Mya, in which there is a layer of large cells occupied by carbonate of lime disposed in a radiated form of crystallisation, resembling that of the mineral called Wavellite. Approaches to this beautiful arrangement may be seen in many other shells. Here, too, we find the partitions between the cells gradually becoming less distinct, as we pass from this peculiar stratum into the surrounding substance, -until we lose them altogether. In general, a cellular layer may be detected upon the external surface of bivalve shells, where this has been protected by a periostracum,or has been prevented in any other mode from undergoing abrasion :\nthus it is found occasionally in Atiomia and Pecten, and generally in Chama, Cleidoth\u0153rus,\nFig. 414.\nSection of the hinge-tooth of Mya arenaria, showini radiating arrangement of carbonate of lime within the cells, and the gradual disappearance of the cell-boundaries, so that the texture becomes homogeneous. Magnified 80 diameters.\nTrigonia, Anatina, Solen, Glycimeris, Solemya. &c. In the last-named genus it is very firm, and leaves a distinct membranous residuum after the calcareous matter has been removed by acid, which is not the case with the others. The cells of which the outer layer of the shell is made up are frequently rather fusiform than prismatic in their shape, and are disposed with their long axes nearly parallel to its surface, so that their extremities \u201c crop out\u201d very obliquely on its exterior, where their rounded terminations, containing nuclei, may often be distinguished when the surface has not suffered abrasion. (See fig. 416.)\nThe internal layer of Bivalve shells rarely presents a distinct cellular structure, when examined in a thin section ; and the residuum left after d\u00e9calcification is usually a distinct but structureless membrane, closely resembling the \u201cbasement membrane\u201d of Mr. Bowman. (Mucous Membrane.) This form of shell-substance may consequently be distinguished as membranous. In the Margaritacece and many other families, this internal layer has a nacreous or iridescent lustre, which depends (as Sir D. Brewster has shown*) upon the striation of its surface with a series of grooved lines, which usually run nearly parallel to each other. As these lines are not obliterated by any amount of polishing, it is evident that their presence depends upon something peculiar in the texture of this substance, and not upon any mere superficial arrangement. When a piece of nacre is carefully examined, it becomes evident that the lines are produced by the cropping-out of lamin\u00e6 of shell situated more or less obliquely to the plane of the surface. The greater the dip of these lamin\u00e6, the closer will their edges be ; whilst the less the angle which they make with the surface,\n* Phil. Trans. 1814.","page":560},{"file":"p0561.txt","language":"en","ocr_en":"SHELL.\n50 i\nthe wider will be the interval between the lines. When the section passes for any distance in the plane of a lamina, no lines will present themselves on that space. And thus the appearance of a section of nacre is such as to have been aptly compared by Sir J. Herschel* to the surface of a smoothed deal board, in which the woody layers are cut perpendicularly to their surface in one part, and nearly in their plane in another. Sir D. Brewster appears to suppose f that nacre consists of a multitude of layers of carbonate of lime alternating with animal membrane ; and that the presence of the grooved lines on the most highly-polished surface is due to the wearing away of the edges of the animal laminae, whilst those of the hard calcareous laminae stand out. If each line upon the nacreous surface, however, indicate a distinct layer of shell-substance, a very thin section of mother-of-pearl ought to contain many thousand laminae, in accordance with the number of lines upon its surface ; these being frequently no more than 1-7500th of an inch apart. But when the nacre is treated with dilute acid, so as to dissolve its calcareous portion, no such repetition of membranous layers is to be found : on the contrary, if the piece of nacre be the product of one act of shell-formation, there is but a single layer of membrane. The membrane is usually found to present a more or less folded or plaited arrangement ; but this has generally been obviously disturbed by the disengagement of carbonic acid in the act of d\u00e9calcification, which tends to unfold the plaits. There is one shell, however, \u2014 the well-known Haliotis splendens,\u2014which affords us the opportunity of examining the plaits in situ, and thus presents a clear demonstration of the real structure of nacre. This shell is for the most part made up of a series of plates of animal matter, resembling tortoiseshell in its aspect, alternating with thin layers of nacre ; and if a piece of it be submitted to the action of dilute acid, the calcareous portion of the nacreous layers being dissolved away, the plates of animal matter fall apart, each one carrying with it the membranous residuum of the layer of nacre that was applied to its inner surface. It will usually be found that the nacre-membrane covering some of these horny plates will remain in an undisturbed condition ; and their surfaces then exhibit their iridescent lustre, although all the calcareous matter has been removed from their structure. On looking at the surface with reflected light under a magnifying power of 75 diameters, it is seen to present a series of folds or plaits more or less regular; and the iridescent hues which these exhibit are often of the most gorgeous description. But if the membrane be extended with a pair of needles, these plaits are unfolded, and it covers a much larger surface than before ; and the iridescence is then completely destroyed. This experiment, then, demonstrates that the peculiar lineation of the surface of nacre (on which the iridescence undoubtedly\n* Edinb. Philos. Journ. vol. ii.\nf Loc. cit.\nVOL. IV.\ndepends, as first shown by Sir D. Brewster), is due, not to the outcropping of alternate layers of membranous and calcareous matter, but to the disposition of a single membranous layer in folds or plaits, which lie more or less obliquely to the general surface.\nThere are several bivalve shells which present what may be termed a sub-nacreous structure, their polished surfaces being covered with lines indicative of folds in the basement membrane ; but these folds are destitute of that regularity of arrangement which is necessary to produce the iridescent lustre. This is the case, for example, with most of the Pecti-nid\u00e6, also with some of the Mytilace\u00e6, and with the common Oyster. Where there is no indication of a regular corrugation of the shell-membrane, there is not the least approach to the nacreous aspect ; and this is the case with the internal layer of by far the greater number of shells, the presence of nacre being exceptional, save in a small number of families.\nThe membranous shell-substance, some form of which constitutes the internal layer of most bivalve shells, is occasionally traversed by tubes, which seem to commence from the inner surface of the shell, and to pass towards the exterior. These tubes vary in size from about the 1-20,000th of an inch, or even less, to about the l-2000th ; but their general diameter, in the shells in which they most abound, is about l-4000th of an inch. The direction and distribution of these tubes are extremely various in different genera. Thus, in Anomia Ephippium they are scantily distributed in the internal nacreous lamina ; but in the yellow outer layer they are very abundant {fig. 415.), forming an irregular network, which spreads out in a plane parallel to the surface. In Cleidoth\u0153rus chamoides, on the other hand, the tubes are abundant in the internal layer of the nacreous lining, where they form an intricate but irregular net-work parallel to the internal surface of the shell ; and from this arise a series of straight tubes, which pass nearly at right angles with the surface, at a considerable distance from each other, through the external portion of the nacreous layer, towards the cellular structure which constitutes the exterior of the shell. This, however, they do not penetrate; stopping short as they approach it, just as the tubes of dentine cease at its plane of junction with the enamel. The diameter of the tubes is tolerably uniform, even when they divaricate ; the trunk not being much larger than either of the branches. In other instances, however, no such net-work is formed, but the tubes run at a distance from each other, traversing the shelly layers obliquely, and are then usually of comparatively large size ; this is the case, for example, with some species of Area and Pectunculus. That these tubes are not mere channels or excavations in the shell-substance, is proved by the fact that they may be frequently seen very distinctly in the decalcified shell-membrane. They often present, in their beaded aspect, indications of a cellular origin, as if they had been formed\no o","page":561},{"file":"p0562.txt","language":"en","ocr_en":"562\tSHELL.\nby the coalescence of a series of cells arranged in a linear direction. They are generally\nFig. 415.\nTubular shell-structure from external surface of Anomia Ephippium. Magnified 250 diameters.\nmost abundant in shells whose exterior has a foliated or sculptured character ; and not un-frequently they may be distinctly seen to pass directly towards the prominences of the surface, \u2014 as in Lima scabra and various species of Chama. They are by no means restricted, however, to shells thus characterised; nor are they universally present in them.\nOf the origin and mode of formation of the membranous shell-structure, it is rather difficult to give an exact account. Possibly, after the epidermic cells have undergone calcification, so as to form the external cellular layer, the basement membrane itself may become detached from the surface of the mantle, in combination with a layer of calcareous matter. Even in nacre, however, which may be considered as the most perfect form of this substance, indications of cellular structure are not unfrequently to be seen, especially in univalve shells : these are particularly evident in Haliotis, the nacreous laminae of which, when carefully examined under a sufficiently high magnifying power, are found to be composed of minute cells of a long oval form (fig. 416.), their short diameter not being above l-5000th of an inch. Their boundaries in many parts are very indistinct, or even disappear altogether, so that every gradation can be traced, from the obviously cellular arrangement shown in fig. 412., to the homogeneous aspect presented by the nacre of bivalve shells. The same cellular structure, and the same gradation to a homogeneous stratum, may be made apparent in the decalcified membrane ; so that here we seem to have evidence that even the membranous shell-substance is originally formed by the agency of cells, although the boundaries of these have usually been subsequently obliterated, so that the structure comes to present a homogeneous aspect. Indications of the same cellular organisation may be detected in the nacreous lining of the shell in Turbo and Nautilus. We seem justified in concluding that nacre\nhas everywhere a similar origin; and if one variety of membranous shell-substance be thus\nFig. 416.\nc\tb\ta\nCellular structure of nacre of Haliotis splendens : the cells cut transversely at a, longitudinally at b, and showing their terminations (with nuclear spots) at c. Magnified 450 diameters.\nproved to have been formed by the agency of cells, little doubt can be entertained as to the corresponding organisation of others. The fact may probably be, that, as maintained by Professor Goodsir *, the basement membrane is itself composed of cells more or less perfectly developed, the boundaries of which usually disappear. Of this view a very good illustration is afforded by the various examples of shell-membrane ; which present every gradation, from the most perfectly homogeneous pellicle, to a distinct stratum of cells.\nThe loss of the original boundaries of the cells, and the consequent obscuration of the real nature of the structure, are by no means peculiar to shell ; for the physiologist is familiar with this change as occurring in various other tissues. Thus, in dentine, the cases in which the vestiges of the original cells are preserved are few in proportion to those in which they are obliterated ; and yet these isolated examples are sufficient to mark the real nature of the transformation of the soft dentinal pulp into the dense ivory. It would seem as if, in the process of calcification, the cell-walls have a tendency to liquefy or dissolve away, unless supported by additional deposits of animal matter, thus allowing the complete fusion of their contents. The peculiar tenacity of the decalcified shell-substance in the Margaritacece and certain other tribes seems due, not so much to the strength of the original cell-walls, as to the interposition of an intercellular substance between them. In Perna we not unfrequently find, between the calcified layers, membranous laminae consisting chiefly of horny matter interposed between rounded cells that are more or less widely separated from each other : here the animal substance\n* Anatomical and Pathological Observations, p. 3, note.","page":562},{"file":"p0563.txt","language":"en","ocr_en":"SHELL.\n563\nwould seem to be peculiarly abundant, being apparently of the same kind as that of which the byssus of these animals is composed.\nThe ordinary account of the mode of growth of the shells of Bivalve Mollusca,\u2014 that they are progressively enlarged by the deposition of new laminae, each of which is in contact with the internal surface of the preceding, and extends beyond it,\u2014does not express the\nwhole truth ; for it takes no account of the fact that most shells are composed of two layers of very different texture, and does not specify whether both these layers are thus formed by the entire surface of the mantle whenever the shell has to be extended, or whether only one is produced. An examination of fig. 417. will clearly show the mode in which the operation is effected. This figure\nVertical section of shell of Unio occidens, near the lip, stowing the arrangement of the outer ^prismatic, and the internal or nacreous layers : a a', b V, cd, successive lines o gr w ,\t, g\nMagnified 8 diameters.\nrepresents a section of one of the valves of Unio occidens, taken perpendicularly to its surface, and passing from the margin (at the right hand of the figure) towards the umbo (which would be at some distance beyond the left). This section brings into view the two substances of which the shell is composed ; traversing the outer or prismatic layer in the direction of the length of its cells, and passing through the nacreous lining, which is seen to be made up of numerous laminae, separated by the lines a a', bb', cc', &c. These lines evidently indicate the successive formations of this layer ; and it may be easily shown, by tracing them towards the umbo on the one side, and towards the margin on the other, that at every enlargement of the shell its whole interior is lined by a new nacreous lamina, in immediate contact with that which preceded it. The number of such laminae, therefore, in the oldest part of the shell, indicates the number of enlargements which it has undergone. The outer or prismatic layer of the growing shell, on the other hand, is only formed where the new structure projects beyond the margin of the old ; and thus we do not find one layer of it overlapping another, except at the lines of junction of two distinct formations. When the shell has attained its full dimensions, however, new laminae of both layers still continue to be added ; and thus the lip becomes thickened by successive formations of prismatic structure, each being applied to the inner surface of the preceding, instead of to its free margin. The same arrangement may be well seen in the Oyster; with this difference, that the successive layers have but a comparatively slight adhesion to each other.\nThe shells of TerebratuJ\u0153, and of several\nother genera of Brachiopoda, or Palliobran-chiate Bivalves, are distinguished by peculiarities of structure, which serve to distinguish them from all others. When thin sections of them are microscopically examined, they present a very peculiar texture, {fig. 418. a.)\nFig. 418.\nPortion of the shell of Terebratula australis, showing the orifices of the perforations, and the peculiar structure of the shell : at a the shell is traversed by the section ; at b is shown its internal surface.\nwhich might be referred either to long flattened cells, or to plications in the shell-membrane ; on the other hand, the natural internal surface of these shells always exhibits an imbricated aspect of great regularity (5). If the section pass very obliquely towards this surface, it becomes evident that these imbrications are formed by the outcrop of the long flattened cells or folds, which were seen when the plane of the section has passed in the direction of\no o 2","page":563},{"file":"p0564.txt","language":"en","ocr_en":"564\tSHELL.\ntheir length. A great variety of appearances is presented by this structure, according to the direction in which it happens to be traversed by the section ; but they are all indicative of its peculiar character, which is readily recognisable even in the minutest fragment, although its nature yet remains doubtful. The cells, if cells they be, must be excessively flattened ; and no vestige of them can be traced in the decalcified shell ; whilst, on the other hand, the membranous residuum does not give any distinct indication of having been plicated with the regularity necessary to produce such a remarkable appearance. When any recent species of Terebratula is examined, save Ter. psittacea (which is now generally excluded from the genus on other grounds), an additional peculiarity is observed ; consisting of the presence of a large number of perforations in the shell, generally passing obliquely from one surface to the other, and terminating internally by an open orifice (fig. 418.), whilst on the exterior they are covered in by the periostracum. Their diameter, which is greatest towards the external surface, varies in different species from about 1-1800th to 1-500th of an inch ; and there is a considerable difference, also, in their degree of proximity to each other. In some fossil species, as Ter. bidlata, the interval between the passages is scarcely greater than the diameter of the passages themselves. When a portion of one of these shells, which has been preserved with the animal in spirit, has been completely decalcified by the action of dilute acid, the membranous residuum presents a very remarkable structure, no vestige of which is seen in the ordinary bivalves. Attached to the membranous films are a series of tubular appendages, corresponding in diameter to the perforations of the shell, and arranged at the same distances (fig. 419.) : the free extremi-\nFig. 419.\nDecalcified, membrane of shell of Terebratula australis, showing the caecal tubuli, which occupy the perforations of the shell : the tubuli are filled with minute cells. Magnified 150 diameters.\nties of these appendages have distinct coecal terminations ; and when a sufficient magnifying power is employed, it is found that their\ncontents are distinctly cellular, resembling the cells in the interior of glandular follicles. These coecal tubuli lie in the perforations of the shell, and open on its inner surface ; but there does not appear to be any system of tubes or canals for collecting the matter poured out from them, each c\u00e6cum having its distinct and independent termination on the internal surface of the shell. The surface of the mantle in contact with the shell is found to be studded with minute cells, corresponding in size and aspect with those contained in the coecal tubuli. The physiological purpose of this curious structure is at present a mystery ; but there can be little doubt that it is a very important one in the economy of the animal, when we see the shell thus rendered subservient to the special protection of the coecal appendages. The perforations are wanting in a large proportion of the very numerous species of fossil Terebratul\u00e6 ; and there would appear strong reason for regarding their presence or absence as a character of fundamental importance in the subdivision of this important genus.* In most of the non-perforated species, the shell is readily divisible ' into thin micaceous plates, which exhibit the characteristic texture of the shell in great perfection ; and as this texture undergoes remarkably little change in the act of fossilisation, it is often possible to recognise a Terebratula from a very minute fragment, imbedded even in the palaeozoic strata. A very similar structure exists in several genera allied to Terebratula ; and in some of these, also, as Orthis and Spirifer, the distinction has to be established between the perforated and non-perforated species ; whilst in Atrypa (to which the recent Ter. psittacea properly belongs), all the species are destitute of perforations.\nThere is not, by any means, the same amount of diversity in the structure of the shell in the class of Gasteropoda, as that which exists among the several tribes of Conchifera ; a certain typical plan of construction being common to by far the greater number of them. The small proportion of animal matter contained in most of these shells is a very marked feature in their character ; and it serves to render other features indistinct, since the residuum left after the removal of the calcareous matter is usually so imperfect, as to give no clue whatever to the explanation of the appearances shown by sections. Nevertheless, the structure of these shells is by no means homogeneous, but always exhibits indications, more or less clear, of an original organic arrangement. The porcelianous shells, as formerly stated (vol. ii. p. 384), are composed of three layers, all presenting the same kind of structure, but each differing from the others in the mode in which this is arranged. This structure was described by Mr. Gra} -j- as the result of rhomboidal crystallisation ; each layer being com-\n* See a Paper on the Subdivision of the Genus Terebratula, by Mr. J. Morris, in the Journal of the Geological Society, vol. ii. p. 382.\nt Phil. Trans. 1833, p. 790.","page":564},{"file":"p0565.txt","language":"en","ocr_en":"SHELL.\t565\nposed of thin laminae placed side by side, which separate from one another in the planes of cleavage when the shell is fractured. As first pointed out, however, by Mr. Bowerbank, each of these laminae really consists of a series of cells in close apposition ; and the plates are disposed alternately in contrary directions, so that each series of cells intersects the one beneath it nearly at right angles, as seen in fig. 420. Although the intimate structure of\nFig. 420.\nortion of fractured surface of middle layer of Cypr&a mauritiana, showing laminae composed of prismatic cells obliquely crossing one another. Magnified 235 diameters. (After Bowerbank.)\neach of the three layers of the shell is essentially the same, yet the disposition of the laminae is not the same in any two adjoining ones, \u2014 an arrangement which adds greatly to the strength of the shell. The planes of the laminae are always as nearly as possible either parallel or at right angles to the lines of growth ; those of the inner and outer layers always having the same direction with each other, but those of the middle layer being set at right angles to them. When, therefore, a section is made parallel to the surface of the shell, it will cut the edges of the laminae of which the layers traversed by it are composed ; but if the section be made in a direction perpendicular to the surface, and pass through the middle layer in the plane of its laminae, it will cut through the edges of the laminae making up the interior and exterior layers ; whilst if the section traverse the two latter in the plane of their laminae, it will cut across the laminae of the middle layer.\nThe principal departures from this plan of structure are seen in Patella, Chiton, Ha-liotis; and Turbo and its allies. In Patella, the inner and outer layers are composed of large and irregular laminae, by no means firmly adherent to one another ; but the middle layer is made up of tolerably regular polygonal cells, which form only a thin stratum in some parts, whilst in others they are elongated into prismatic cells; and the directions of the laminae, of which the inner and outer layers are composed, instead of\nbeing conformable with each other, are at right angles. In Chiton, the external layer, which seems to be of a delicate fibrous texture, but which is of extreme density, is perforated by large canals, which pass down obliquely into its substance, without penetrating, however, as far the middle layer. The middle layer, as in Patella, is distinctly cellular ; whilst the internal has the same nearly-homogeneous texture as the external, but shows no trace of perforations. The peculiarities of structure presented by Ha~ liotis have been already described. In Turbo and its allies, the inner layer is nacreous, and the middle one is made up of large cells : the cellular structure is also very evident in the solid operculum of Turbo, when reduced to sufficient thinness.\nThat the shell-substance in Gasteropoda is formed in the first instance by the agency of cells, however indistinct their traces may subsequently become, is further apparent from the researches of Mr. Bowerbank on the growth of the shell of the common garden-snail (jHelix aspersa) ; and his observations further confirm the opinion already expressed, that the formation of each layer of shell is a progressive operation ; new matter being added to its interior after the exterior has been consolidated.\nPassing by the Pteropoda, whose delicate membranous shells present no very distinct structure, we come to the testaceous Cephalopoda, of which there are but few species now existing. The shell of Nautilus pompilius bears more resemblance to that of bivalves in its intimate structure, than to that of the Gasteropodous univalves ; the three layers of perpendicular lamin\u00e6, so characteristic of the latter, not making their appearance here; and of the two layers of which the shell is composed, the inner one being nacreous, whilst the outer one is made up of an aggregation of cells of various sizes, those which are nearest the external surface being generally the largest. In the thin shell of Argonauta, the same kind of irregular cellular structure can be easily distinguished, as in the outer layer of the shell of Nautilus; but there would seem to be nothing comparable to the inner layer of the latter. The shell of Spi-rula must be considered to bear a greater resemblance, as regards its relation to the animal, to the Sepiostaire of the Cuttle-fish, than to the chambered shell of the Nautilus although it so closely approximates the latter in its own conformation. This being the case, it is interesting to find that the intimate structure of the shell has a much greater resemblance to the Sepiostaire than would be supposed from its general aspect. For although its texture seems uniform, and its minute parts are composed of an aggregation of calcified cells, yet its surface is marked by sinuous lines, closely resembling those which are seen upon the transverse plates of the Sepiostaire ; and these lines or bands project in such a degree, that they might be considered as rudiments of the vertical partitions\no o 3","page":565},{"file":"p0566.txt","language":"en","ocr_en":"566\nSHELL.\nwhich connect these plates. The Sepiostaire having been formerly described in some detail (vol. i., p. 546), it will only be requisite here to mention, that the calcified layers which alternate with horny membranes to form the shallow cone or cup, exhibit a distinct cellular structure, when the section is made sufficiently thin ; and that indications of a similar structure may also be perceived in the delicate and fragile plates which are arranged obliquely upon one another in the hollow of this cup. Few of the numerous fossil shells referable to this class have yet been examined ; it may, however, be stated as an interesting result of microscopic observation, that the \u201c spathose guard \u201d of the Belemnite is thereby proved to be composed of long prismatic cells, radiating from the centre to the circumference; closely resembling in their general arrangement those of the massive tube of Septaria gigantea, the great sand-boring Teredo of Sumatra.\"\nThe structure of the shells of the testaceous Annelida, and of the pedunculate Cirrho-poda, does not essentially differ from that of Mollusca ; but in most of the sessile Cir-rhopods, such as the common Balanus, we find a cancellated structure or diplo\u00eb intervening between the inner and outer plates of the shell (vol. i., p. 685). A less regular\nFig. 421.\nCancellated structure from shell of Hippurite, as seen in transverse section. Magnified 5 diameters.\ndiplo\u00eb has been described by Mr. J. E. Gray* as existing between the laminae of Ostrea purpurea ; but in no other shells of existing Mollusca has any approach to it been yet discovered. A very regular cancellated structure, however, is exhibited in the singular extinct group of jRudist.es, where it makes up nearly the entire thickness of the shell (fig. 421.). The cancelli are usually short hexagonal prisms, terminated at each end by a flat partition ; consequently', a section taken in one direction (fig. 421.) will exhibit the walls of the chambers disposed in a hexagonal network ; whilst a section that passes at right angles to this will bring into view the trans-\n* Magazine of Zoology and Botany', vol. ii. p. 228.\nverse partitions (fig. 422.). The cancelli are frequently occupied by calcareous infiltra-\nFig. 422.\nCancellated structure from the shell of Hippurite, as seen in vertical section. Magnified 5 diameters.\ntion ; which might lead to the belief that, like the cells of the Pinna, they were so consolidated in the living state. But they are also to be met with entirely empty, or with their walls merely lined by calcareous crystals ; so that there can be no doubt that they were originally hollow. The presence of \"this structure assists in determining the zoological position of the curious group in question, which many considerations would lead us to regard as having been interme-\u25a0diate between the Bivalve Mollusca and the sessile Cirrhopoda. And it may be added \u25a0that, by the same evidence, the place of the curious Pleurorhyncus hibernicits, a fossil which has been assigned to a different tribe by almost every naturalist who has examined it, would unhesitatingly be determined as amongst the Rudistes.\nEchinodermata. \u2014 The structure of the skeleton in this class is entirely different from that which we have found to be characteristic of the Mollusca ; whilst, in its essential features, it presents a remarkable uniformity throughout the various members of the group. The general arrangement of its components is the same, for example, in the firm plates which make up the testa of the Echinida, in the joints of the stems and branches of the Crinoidea, and in the scattered calcareous deposits which are met with in the integuments and in the tentacula of the Holo-thurida.\nThe elementary structure of the skeleton of the Echinodermata may be described as a net-work, composed of calcareous and animal matter intimately united ; the former, however, being greatly predominant. In this net-work, the interspaces or areol\u00e6, and the solid structure which surrounds them, may bear an extremely variable proportion to one another ; so that, in two masses of equal size, the one or the other may greatly pre-","page":566},{"file":"p0567.txt","language":"en","ocr_en":"SHELL.\ndominate, and the texture may have either a remarkable lightness and porosity, or a considerable degree of compactness and brittleness. We may take the plates making up the shell of the Echinus as presenting a typical form of this structure ; from which the transition is easy towards either the more solid or the more open character which it elsewhere presents. When we obtain a very thin slice of one of these plates, taken parallel to the surface of the shell, we find that it is composed of a lamina, apparently in itself destitute of structure, perforated with considerable regularity by apertures of a circular or oval form. The diameter of these apertures (fig. 423.) varies to a certain extent in\nFig. 423.\nThin Lamina of shell of Echinus, showing its areolar structure: a a, portions of subjacent layer; bb,\nfractured bases of columns connecting the superposed laminae. Magnified 164 diameters.\ndifferent parts of the same shell, the reticulation being much coarser in the inner than in the outer layers : from numerous measurements, the extremes may be stated at about 1-450th and l-2500th of an inch. The entire thickness of the shell is made up of an immense number of such plates, which lie parallel to each other, but not in contact ; for they are separated from each other by little pillars, which rise up vertically from each plate to support the next, and which thus connect the different plates whilst holding them apart. The broken bases or ends of these minute pillars are commonly to be seen upon the surfaces of the perforated plates, at the spots intermediate between three or four of the apertures (fig. 423. b, b). The successive plates are always so disposed, that the centres of the perforations of one shall correspond with the intermediate solid structure of the next (fig. 423. a, a) ; and their transparency is such, that, when we have reduced a section to such a degree of thinness as to contain a small number of the reticulated layers, it is easy, by a proper adjustment of the focus of the microscope, to bring either one of them into distinct view. In whatever direction we slice the shell of the\n567\nEchinus, we always meet with a sort of reticulated structure ; for if our section be parallel to the surface of the plates, it brings into view one or more of the perforated laminae just described; whilst, if it be perpendicular to the surface, it passes vertically through a series of these laminae, and in the direction of the pillars that connect them, which thus constitute an areolar structure of a tolerably regular form. The testa is thus of an extremely porous character, the areolae having the freest communication with each other. Even in the living state, however, the areolae appear to be empty, the ingress of the fluid with which the surface of the shell is in contact being prevented by the delicate membrane that covers it. At the same time, it possesses a remarkable degree of strength, in proportion to the amount of solid matter employed in its construction ; for every part at the same time supports, and is supported, by the surrounding fabric.\nThe skeleton of the Echinodermata contains very little organic matter. When it is submitted to the action of dilute acid, so that the calcareous matter is removed, the residuum is very small in amount ; indeed, unless the acid be so weak as only just to dissolve the carbonate of lime, the organic matter also will be dissolved, and no animal basis will be apparent. When, however, it is obtained in a state fit for examination, it is found to possess the reticular structure of the calcareous shell ; the meshes or areol\u00e6 being bounded by a substance in which a fibrous appearance, intermingled with granules, _ may be discerned under a sufficiently high magnifying power, as was first pointed out by Professor Valentin. This tissue bears a close resemblance to the areolar tissue of higher animals ; and the shell may probably be considered as formed, not by the consolidation of the cells of the epidermis, as in the Mollusca, but by the calcification of the fibro-areolar tissue of the true skin. This calcification of areolar or simply fibrous tissue, by the deposit of mineral substance, not in the meshes of areol\u00e6, but in intimate union with the organic basis, is a condition of much interest to the physiologist ; for it presents us with an example, even in this low grade of the animal kingdom, of a process which seems to have an important share in the formation and growth of bone, viz. the progressive calcification of the fibrous tissue of the periosteum.*\nNot only the entire shell, but the framework by which the teeth of the Echinus are enclosed and supported, is composed of a calcareous reticulation similar to that now described ; nor is it confined to these solid structures. It has been pointed out by Professor Valentin, that the buccal membrane contains isolated patches of extreme delicacy; and the same eminent observer has detected a most beautiful example of this\n* See Dr. Sharpey\u2019s Introduction to the Fifth Edition of Dr. Quain\u2019s Anatomy, p. 148, et seq.\no o 4","page":567},{"file":"p0568.txt","language":"en","ocr_en":"568\nSHELL.\nstructure in the calcareous rosette, with which, as long since observed by Monro, the sucker at the extremity of each am-bulacral tube is furnished. But it is in the spines with which the shell is beset, that the most remarkable displays of it are to be met with ; for it is there disposed in connection with solid ribs or pillars, which increase the strength of these organs, in such a manner as to constitute a most regular and elaborate pattern, which appears to differ in every distinct species. When we make a thin transverse section of almost any spine belonging to the genus Echinus, we are at once made aware of the existence of a number of concentric layers, arranged in a manner that strongly reminds us of the layers of wood in the stem of an exogenous tree. The number of these layers is extremely variable ; depending, not merely upon the age of the spine, but upon the part of its length from which the section is taken. The centre of the spine {fig. 424. a.) is filled up\nFig. 424.\nTransverse section of spine of Echinus : a, medullary centre ; bb, first layer of solid pillars ; cc, dd, e e, ff, successive rings of growth. Magnified 45 diameters.\nwith the same kind of calcareous net-work as that of which the shell is composed ; and this is sometimes so delicate, as to appear as if made up by the interlacement of mere threads. This medullary centre is bounded by a row, more or less circular according to the form of the spine (which is sometimes angular), of open spots (b, b, b), in which it is deficient : these, on a cursory inspection, might be supposed, from their transparency, to be void spaces ; but a closer inspection makes it evident that they are the sections of a circular row of solid ribs or pillars, which form the exterior of every layer. Their solidity becomes very obvious when we either examine a section of a spine whose substance is pervaded (as frequently happens) with a deep colour, or when we look at a thin section of any spine by polarised light. Around the first circle of these solid pillars,\nwe find another layer of the fibro-calcareous net-work, which again is bounded by another circle of solid pillars, whose transverse sections are seen at c, c, c. The same arrangement may be repeated many times, (dd, ee). On looking at the outer border of the section, we observe that the rounded sides of these pillars (ff) form a series of projections with hollows between them ; and these exactly correspond with the projecting ribs and furrows which we may notice running along the natural surface of the spine when we examine this with a magnifying glass, or even (in some instances) with the naked eye.\nAlthough there is nothing like interstitial growth in the shell or spines of the Echinus, yet both are progressively enlarged by the addition of new matter. The polygonal plates of which the shell is composed are separated from each other by a membrane that passes into every suture ; and the margins of each plate appear to receive periodical additions, by calcareous deposit in the substance of this membrane. In this manner the globular form of the entire shell is preserved, whilst it undergoes progressive enlargement ; new plates being added, as they may be required, round the anal orifice of the shell (Agassiz). There can be little doubt that the spines are, in like manner, periodically augmented in diameter by successive formations or acts of growth, which take place in the investing membrane ; and a longitudinal section of the spine makes it evident that these additions not only surround the preceding deposits from the base upwards, but pass considerably beyond them, thus adding to the length of the spine. The consequence is, that a transverse section taken near the base of the spine will exhibit all the layers of which it is made up, each layer being narrow, and the central medulla small. A section taken at about the middle of the length may very probably not cut across the original spine nor the older layers, which do not reach so far ; and a section taken across the spine near its apex will only traverse the one or two layers last formed. Nevertheless, in many species, the spine is larger at that part than near its base ; but the large size is due to the great expansion of the medullary centre, which is composed of a very loose calcareous reticulation.\nThe structure of the shell of the Echinus is repeated in that of the three genera which may be regarded as the types of the principal subdivisions of the order Echinida, \u2014 namely, Cidans, Clypeaster, and Spatangus : there can be no reasonable doubt, therefore, that it is universal throughout the group. The spines, however, of Cidaris, present a marked variation from the plan of structure exhibited in Echinus ; for they are usually nearly cylindrical in form, destitute of concentric layers, and composed of a calcareous reticulation enveloped in a cylinder of a solid, apparently homogeneous substance, chiefly calcareous,","page":568},{"file":"p0569.txt","language":"en","ocr_en":"SHELL.\n569\nwhich rises up in ridges upon the exterior. Hence it would appear that, like endogenous trees, whatever additions these spines may receive in length, they can receive little or none in diameter. The slender, almost filamentary species of the Spatangace\u00e6, and the innumerable minute hair-like processes attached to the shell of the Clypeasterid\u00e6, are composed of a like regular reticulated tissue ; many of these are extremely beautiful objects when examined with the microscope without any preparation. It is interesting also to remark, that the same structure presents itself in the Pedicellarice, which are found upon the surface of many Echinida, and which have been so great a source of perplexity to naturalists. The complete conformity which exists between the structure of their skeleton, and that of the animal to which they are attached, would seem to remove all reasonable doubt that they are truly appendages to it ; as their actions also would indicate.\nThe same structure presents itself in the calcareous plates which form the less perfect skeletons of the Asteriadce, and also in their spines, when these (as in the large Goniaster equestris) are furnished with a calcareous frame-work, and are not mere projections of the hard integument. It is also met with in the family Ophiuridce, which forms, in some respects, the transition to the Crinoidal group ; but the calcareous skeleton is here generally subordinate to the firm and almost horny integument. In the Crinoidea, on the other hand, the calcareous skeleton is highly developed, and its structure is extremely characteristic. This is well displayed in the recent Pentacnnus Caput Medus\u0153, the stem and branches of which are made up of a calcareous net-work, closely resembling that of the shell of the Echinus. There is exhibited, moreover, in a transverse section of the stem of Pentacnnus, as in the spines of Echinus, a certain regular pattern, which results from the varying dimensions of the areolae in different parts. This pattern, formed by the extension of five \u2018pairs of rays (strongly reminding us of the medullary rays of plants) from the centre towards the circumference, is frequently well preserved in the fossilized stems of Pentacrini, and varies in different species sufficiently to serve as a distinctive character. In the round-stemmed Encrinites, a transverse section of the joints exhibits a simple concentric arrangement.\nIt only remains for us to notice the order Holothurid\u0153, in which, as is well known, the calcareous skeleton of the other Echinoder-mata is reduced to its most rudimentary condition; never forming a complete and connected framework, but only showing itself in detached pieces, the disposition of wrhich is extremely variable. In the typical Holo-thuria, there are five solid calcareous plates around the mouth, in which the calcareous reticulation is very characteristically seen. Each of the tentacula, also, has a small calcareous disk at its extremity, which presents a sort of rude sketch of the beautiful struc-\nture of the rosette that supports the ambu-lacral suckers of the Echinus.\nThere can be no reasonable doubt that this peculiar arrangement is universal throughout the group, since it has been detected in characteristic examples of every one of its principal subdivisions. And, consequently, as no similar calcareous reticulation is found in the internal or external skeleton of any other animal, even the minutest fragment which distinctly presents this structure may be referred with certainty to an Echinoderm. And this structure is perfectly preserved, even after the substance has been infiltrated with calcareous matter in the act of fossilization, and has become so completely mineralised, that the disposition to rhomboidal fracture makes it difficult to obtain a section in any other direction than that of the plane of cleavage. As already remarked, the elementary structure is essentially the same everywhere ; so that it might not be possible to determine from a very minute fragment whether it formed part of the shell of an Echinus, Cidaris, or Spatangus,\u2014a portion of the framework of an Asterias, Ophiura, or Holothuria, \u2014 or entered into the composition of the stem of an Encrinite. But where any regular pattern is displayed, this is frequently sufficient to distinguish the genus, or even the species, to which the fragment belonged. This is certainly the case in regard to the spines of Cidarites and the stems of Pentacrinites ; and will probably be found no less true in other instances, when these beautiful structures shall have been more extensively investigated.\nCrustacea. \u2014 The structure of the shell in Crustacea has been hitherto examined only in the Decapod order ; and that of the common crab ( Platycarcinus pa gurus) alone has been subjected to a minute investigation. It is in the Decapod order that the shell attains its most perfect development, and contains the largest proportion of mineral matter : the special respiratory apparatus in this order being so elaborate as to render unnecessary any participation of the general tegumentary surface in the function of respiration. (See vol. i. p. 752.)\nThe shell of the Decapod Crustacea consists of three layers;\u2014namely, 1. a horny epidermic membrane covering the exterior ; 2. a cellular or pigmentary stratum ; and 3. a calcareous or tubular substance. The horny epidermic membrane is easily detached from the subjacent layers, after the shell has been immersed for a time in dilute acid ; it is thin but tenacious, presenting no trace of structure, though it may exhibit markings on the under surface, derived from its contact with the cellular layer beneath. The pigmentary stratum is very thin in the crab and lobster ; but in some other Decapods it is much thicker. In Scyllurus latus, it is stated by M. Lavalle to be the thickest of the three layers of the shell ; and in the cray-fish and many other species, according to the same observer, it seems made up of a considerable number of layers, its vertical section being traversed by several ex-","page":569},{"file":"p0570.txt","language":"en","ocr_en":"570\nSHELL.\ntremely fine lines, passing in a direction parallel to the surface of the shell and to each other. The number of these is usually from six to fifteen ; but they sometimes amount to as many as thirty, or even sixty, their number not being in relation either to the thickness of the pigmentary layer, nor to the size of the species observed ; but appearing to augment with age. The cellular layer is that in which the colouring matter of the shell is solely contained ; but it does not always contain pigment, its structure being precisely the same on the white under-surface of the crab as on the reddest portion of its carapace. When examined with a low magnifying power, it presents an areolar aspect; but when a sufficiently thin section is viewed by transmitted light with a high magnifying power, the character of the net-work, and of the dark spaces it encloses, becomes at once apparent. It is\nFig. 425.\nCells of pigmentary layer of shell of Crab ; a, papillary elevation of subjacent layer. Magnified 400 diameters.\nthen obvious that the nearly colourless polygonal reticulations are the thickened walls of cells, each of them being divided by a distinct line, which marks the junction of the contiguous boundaries ; whilst the dark spaces or areolae are the cavities of the cells, filled with colouring matter, or with some other semiopaque substance. This cellular layer is not uniformly disposed over the entire surface of the crab-shell ; for the calcareous layer beneath rises up through it in little papillary elevations (J%. 425. a), to the summit of which the epidermis adheres. It is from the deficiency of the pigmentary layer at these points, that the shell derives its minutely speckled appearance.\nThe internal layer is that which constitutes by far the thickest part of the shell of the crab, and which must be regarded as its fundamental or essential element, since (according to M. Lavalle) it is never wanting in the Decapod Crustacea, whilst other layers are sometimes deficient. It is in this internal layer, that the calcareous matter is chiefly deposited ; but even after this has been removed, a very distinct animal basis is left,\npossessing considerable firmness, and closely resembling that which is left after the d\u00e9calcification of dentine. When a thin section of it is made parallel to its surface, and subjected to a high magnifying power, it is seen to be composed of an apparently homogeneous substance, studded with minute points, each surrounded by a clear space, which correspond with those seen in a section of dentine cut at right angles to the course of its tubuli, and which would seem to possess the same essential character with them. A thin section of the shell taken in the opposite direction (i. e. from surface to surface) leaves no doubt, when examined with a sufficient magnifying power, of the nature of these markings ; for they are then clearly seen to be the orifices of tubuli, which pass with great regularity from one surface of the shell to the other, lying nearly parallel to each other, and having their usually straight course interrupted at tolerably regular intervals by minute sinuosi-\nFig. 426.\nE. W Uisms\nPortion of transverse section from claw of Crab.\nMagnified 400 diameters.\nties resembling the \u201c secondary curvatures \u201d described by Prof. Owen in the dentinal tubuli. These sinuosities correspond with bands which are seen to traverse the section, running parallel to the surfaces of the shell ; and they appear, like those of dentine, to indicate the successive stages of calcification of the animal basis. This structure is particularly well seen in the black extremities of the claws of the common crab, in which the intertubular substance is quite transparent in a thin section, and of which the hardness and density are as great as in many varieties of dentine ; and as the tubuli are seen, in a transverse section of the claw, to radiate from the central cavity towards the surface, the resemblance to a section of a tooth is altogether so close, as quite to deceive an observer unacquainted with the substance he is examining. The same structure exists, however, in the remainder of the shell; but from some diff\u00e9rence in its molecular constitution, the intertubular substance has a less dense and tenacious character, and has an opaque chalky aspect, which renders even a very thin","page":570},{"file":"p0571.txt","language":"en","ocr_en":"SHOULDER JOINT \u2014 (Normal Anatomy).\t571\nsection of it impermeable to light, unless it be saturated with Canada balsam, which then very commonly enters the tubuli, and prevents them from being readily distinguishable. The purpose of the extraordinary density possessed by the extremities of the claws, is evidently to adapt them to the various mechanical uses to which the animal applies them : and it is interesting to see that this is attained without any variation in the organic structure of the part, but merely by a more intimate union, as it would seem, of the solidifying mineral matter with the organic basis. It does not seem improbable that the phosphate of lime which is known to be present with the carbonate in the shells of Crustacea, may exist in larger proportion towards the extremities of the claws than in other parts of the shell ; a question well worthy of chemical investigation.\nThe periodical exuviation of the shell does not appear to be common to all Crustacea ; for, according to Mr. Couch*, it does not take place in many of the sessile-eyed tribes, whose cases are as dense as those of the pedunculate orders. It is much to be desired that careful observations should be made on the formation of the new shell in the Crab ; since these would probably throw light on much that still remains obscure in the development of dentine.\n[The author of the forgoing article is desirous that it should be understood that all the statements contained in it, except such as are expressly made on the authority of others, are the result of his own observations ; the general facts regarding the organic structure of the shells of Mollusca, Echinodermata, and Crustacea, having been determined by him in the year 1842, and embodied in a paper read before the Royal Society, Dec. 22 of that year, of which the first of the memoirs cited is an abridgment ; and the subject having been subsequently worked out by him in detail, with the aid and encouragement of the British Association, to the reports of which he would refer the reader who may desire additional information as to the results of his researches.]\nBibliography. \u2014 Carpenter, On the Microscopic Structure of Shells, in Annals of Natural History, Dec. 1843 ; and in Reports of British Association for 1844 and 1847. Bowerbank, On the Structure of the Shells of Molluscous and Conchiferous Animals, in Transact, of Microscopical Society, vol. i. London, 1844. G. Valentin, Anatomie du Genre Echinus, in Monographies d\u2019Echinodermes vivans et fossiles, par L. Agassiz : Neufchatel, 1842. Lavalle, Recherches d\u2019Anatomie Microscopique sur le test des Crustac\u00e9s D\u00e9capodes; in Annales des Sciences Naturelles, Juin, 1847.\n(W. B. Carpenter.)\nSHOULDER JOINT (Normal Anatomy of), f The scapular and the axillary regions are each limited externally by the\n* Report of Cornwall Polytechnic Society, 1843. f This article includes the surgical anatomy of the scapulo-liumeral articulation.\nregion of the shoulder-joint ; the latter also unites the two former regions to each other.\nThe region of the shoulder joint {le moignon de V\u00ebpaule) exhibits a rounded projection, due to the angle formed by the union of the arm with the shoulder ; and to the surgical anatomist it possesses extreme interest, because its skeleton is formed by the shoulder-joint.\nSome difficulty arises in assigning to this surgical region precise limits. Anteriorly, it is separated from the pectoral region, by the narrow space between the deltoid and the great pectoral muscles (the coraco-deltoid groove, Velpeau) ; above, it is limited by the convex projection of the acromion process, and by the outer end of the clavicle ; posteriorly, it is confounded with the scapular region ; whilst inferiorly, it extends as far as the insertion of the folds of the axilla.\nThe elements of which this region is composed, are the following : under the superficial coverings lie the deltoid muscle (the greater portion of which belongs exclusively to this space), and in it and beneath it, the branches of the circumflex arteries, and of the great circumflex nerve ; still deeper are situated the exterior of the capsule of the shoulder-joint, the neck and tuberosities of the humerus, the acromion and coracoid processes, with the attachment to them of numerous muscles and ligaments.\nIn this article it is proposed to notice, first, the structures in the scapulo-humeral region which are superficial to the joint ; and, secondly, to describe the anatomical characters oi the shoulder joint itself.\nIn removing the integuments and subcutaneous layer of areolar tissue which covers the deltoid muscle, the anatomist brings into view numerous small branches of nerves from the cervical plexus (supra-acromial twigs), some of the fibres of origin of the platysma myoides, and some small venous branches which, after anastomosing freely with one another, terminate in the cephalic or axillary trunks.\nBy the removal of its investing fascia, the deltoid muscle is next exposed : in its origin it corresponds accurately to the insertion of the trapezius ; hence these two muscles are direct antagonists of each other. The fibres of the deltoid muscle arise from the anterior edge of the outer third of the clavicle and of the acromion process, and from the lower margin of the spine of the scapula : from this extensive line of origin, the fibres in descending converge to the humerus, and are inserted on the outer aspect of that bone into a rough surface called the deltoid impression. The insertion of the muscle is outside the limits of the scapulo-humeral region, and belongs to that of the arm, whilst its posterior portion is contained in the scapular region ; so that the anterior, upper, and central portions of the deltoid alone belong to the region under consideration. Immediately beneath the clavicle, the anterior edge of the deltoid is separated from the pectoralis major by a triangular interval, of which the base, placed superiorly,","page":571},{"file":"p0572.txt","language":"en","ocr_en":"SHOULDER JOINT \u2014 (Normal Anatomy).\n572\nis formed by the bone, whilst the edges are constituted by the adjacent muscles ; in-feriorly, the interstice becoming smaller degenerates into a groove, which continues to separate the muscles from each other, until at length the clavicular fibres of the great pectoral unite with the deltoid, and are inserted conjointly with it into the humerus. In this muscular interstice the cephalic vein is lodged, which, ascending to the triangular space below the clavicle, there dips into the axilla, and joins the axillary vein. The descending branch of the thoracica acro-mialis (arteria thoracica humer aria') descends in the same groove, twisting in a spiral manner around the cephalic vein. More deeply still the ligamentum bicorne, enclosing between its layers the subclavius muscle, may be seen. The axillary vein and artery, brachial plexus of nerves, and inferior to these and crossing before them, the lesser pectoral muscle, may also be made apparent in this space ; but to bring these latter parts into view, the anatomist must first freely separate the muscles from each other.\nIt has been proposed by Hodgson, in order to place a ligature around the axillary artery in the first stage, to cut between the pectoral and deltoid muscles, and then to separate the clavicular attachment of the great pectoral to an extent sufficient for insulating and tying the artery.\nAs in other radiated muscles, the tendinous structure of the deltoid is chiefly placed in its interior ; as many as three or four laminae attached to the bone above, penetrate into the substance of the muscle, and multiply the points of origin of its fleshy fibres. The fasciculi, of which the deltoid muscle is composed, like those of the glutaeus maximus, which is its analogue in the lower extremity, are remarkably coarse and large.\nWhen the deltoid is cut across and reflected, the following parts are found in relation with its deep surface ; anteriorly is seen the coracoid process and the insertions of the pectora-lis minor, of the coraco-brachialis, and of the short head of the biceps into its inner edge, and of the ligamentum bicorne (coraco-clavi-cular ligament) into its summit ; external to the coracoid process is a triangular space, the sides constituted by the opposed edges of the coracoid and acromion processes, the apex placed superiorly at the clavicle, the base inferiorly formed by the convex prominence of the head of the humerus ; this space, filled by the coraco-acromial or triangular ligament, should be familiar to the surgeon, as the point of the knife must be here introduced when disarticulation at the shoulder-joint is being performed after the method of MM. Champesme and Lisfranc. Immediately beneath the coraco-acromial triangle the capsular ligament is situated, and a large bursa (subdeltoid) which intervenes between it and the deep surface of the deltoid muscle ; still lower down, the insertions of the capsular muscles into the tuberosities of the humerus, also the\nneck of the humerus, and the bicipital groove, present themselves. The bicipital groove looks directly forwards and lodges the long tendon of the biceps ; into its anterior edge the tendon of the pectoralis major is inserted, whilst those of the latissimus dorsi and teres major take attachment to the very bottom of the groove, passing a little below the level of the former. The anastomosis of the circumflex arteries, and the circumflex nerve in a great part of its course, constitute also remarkable relations to the deltoid, separating it from the neck of the humerus ; and under the posterior division of the muscle are placed the infra-spinatus, teretes and latissimus dorsi muscles, with the triangular and quadrilateral spaces which they circumscribe. ( Vide Scapular Region.)\nThe anterior and the posterior fibres of the deltoid may act independently of each other, and draw the arm forwards and upwards, or backwards and upwards, respectively. The central portion of the muscle is the principal abductor of the upper extremity ; although its insertion is at a considerable distance from the fulcrum, and the power arm of the lever on which it acts is therefore of considerable length, yet the efficient power of the muscle, relatively to its size, is feeble, owing to the fibres whilst in action being invariably parallel to the lever which they are raising. In this action the deltoid is assisted by the supra-spinatus muscle.\nSCAPULO-HUMERAL ARTICULA TION. The\nscapulo-humeral articulation is formed by the contact of the head of the humerus with the glenoid cavity of the scapula. This, the principal articulation of the upper extremity, is placed at the superior and external portion of the trunk, behind the line of the axis of the hip-joint ; an arrangement which is productive of this advantage, that the most important motions of the upper extremity (those in the direction forwards)Tiave a more extensive range than if the articulation had been located nearer to the anterior aspect of the thorax.\nThe arrangement of the articular surfaces and of the ligamentous structures belonging to the shoulder joint, accords with the general plan on which the bones and articulations of the upper extremity are constructed ; \u201c the disposition and structure of the bones of the upper extremity afford a marked contrast to those of the lower ; the latter are organs of support, and therefore are solid, firm, strong, and withal elastic. The former are destined to perform extended motions, as well as minute and nicely adjusted ones, and therefore, while they possess all the requisite strength, they are light, present little expanse of surface, and are articulated by numerous very moveable articulations.\u201d (Todd and Bowman's Physiological Anatomy, vol. i. p. 147.)\nThe varied uses fulfilled by the upper extremity, added to its remarkable mobility, especially predispose the shoulder joint to accidents ; but as we proceed we shall take","page":572},{"file":"p0573.txt","language":"en","ocr_en":"SHOULDER JOINT \u2014\noccasion to point out the abundant provisions which exist to counteract this tendencv-\nAs regards its motions, and the anatomical dispositions of its connecting media, the shoulder joint belongs to the class of \u201c Enar-throdial Articulations ;\u201d but, if its bony constituents alone be considered, it seems more nearly allied to the \u201c Arthrodia.\u201d This is owing to the imperfect development of the glenoid cavity which is opposed to the head of the humerus.\nThe shoulder joint is constructed after the same plan in all vertebrate animals whose anterior extremities are developed.\nIn this article the several components of the scapulo-humeral articulation shall be described in the following order: \u2014\n1. The Bones. 2. The Structures which facilitate their motions, a. Articular Fibro-Cartilage. b. Articular Cartilage, c. Synovial Membrane. 3. The Connecting Media, a. Passive connecting Media \u2014 the Ligaments, b. Active connecting Media \u2014 the Muscles ; in connection with the detail of the Mechanical Functions of the joint.\n1. Bones.\u2014We shall speak of these briefly, as they have been already described in the article Extremity.\nThe bones which enter into the formation of the shoulder joint are, the head of the humerus and the glenoid cavity of the scapula. These opposed surfaces are of very disproportionate size, the shallow cavity of the scapula not exceeding in dimensions one-third of the head of the humerus.\nThe glenoid cavity is placed at the anterior superior angle of the scapula, below and between the acromion and coracoid processes ; a slight constriction, the neck of the scapula, separates it, together with the coracoid process, from the body of the scapula ; superiorly, the neck of the scapula traverses the notch in the superior costa of the bone, behind the base of the coracoid process ; infenorly, it terminates close to the lower extremity of the articular surface. The aspect of the glenoid cavity in the quiescent state of the scapula, is upwards, forwards, and outwards ; it presents an ovoid outline, the larger end below, and the smaller above. A vertical line falling upon the axillary margin of the scapula divides this articular cavity into two unequal portions, of which the inner is the larger. This arrangement in some degree diminishes the tendency to displacement inwards of the head of the humerus, to which, for other reasons, the joint is strongty disposed.\nAn \u201carrest of development\u201d may cause a deficiency of either the outer or the inner lip of the glenoid cavity, resulting in a congenital dislocation of the head of the humerus, inwards or outwards, according to the portion of the cavity which is deficient. These constitute the \u201csub-acromial\u201d and \u201csub-coracoid \u201d dislocations described by Dr. R. Smith.*\nBoyer supposes that a deficient develop-\n* Dublin Journal of Medical Science, vol. xv., 1839.\n(Norjial Anatomy).\t573\nment of the outer lip of the glenoid cavity must pre-exist, in order to permit the dislocation backwards on the dorsum of the scapula to occur.*\nA little external to its apex, a slight notch in the margin of the glenoid cavity marks the place of attachment of the long tendon of the biceps ; whilst on its upper and inner side a shallow groove points out the passage of the tendon of the subscapularis muscle.\nThe head of the humerus presents a convex hemispherical surface, the aspect of which is upwards, backwards, and inwards. An irregular wavy line separates the head from the anatomical neck of the bone, the latter intervening between the head and the tuberosities. The line which marks the union of the upper epiphysis with the shaft of the humerus has been long incorrectly described, as though it were identical with the anatomical neck. The upper epiphysis comprises not only the head of the bone, but also the tuberosities; for though, doubtless, the line of junction between the upper epiphysis and the shaft corresponds internally to the anatomical neck immediately beneath the cartilage of incrustation, yet from this its direction is chiefly outwards, so that externally it passes below the greater and the lesser tuberosities, traversing the bicipital groove which is included between them.\nThis anatomical fact, and the practical inferences derivable from it, have been clearly pointed out by Dr. R. Smith.f\n2. Structures which facilitate motion in the joint.\u2014a. The border of the glenoid cavity has attached to it a fibro-cartilaginous rim (glenoid ligament) by which the depth of the cavity is somewhat increased. This structure is thickest at its attachment to the bone ; its free edge is very thin ; a section of it made at right angles to the bone gives it a triangular outline. Both its surfaces are lined by synovial membrane, which consequently separates it externally from the capsular ligament ; superiorly, many fibres of the biceps tendon become continuous with the fibrous portion of the so-called \u201c glenoid ligament,\u201d and after prolonged maceration the tendon will separate from the bone along with this structure, but to describe the glenoid ligament as formed by the splitting of the tendon of the biceps, would be erroneous. The glenoid ligament is subservient to the following purposes : it deepens the shallow glenoid cavity, and so lessens the liability to dislocation ; it prevents the bony surfaces of the neck of the humerus, and the edge of the glenoid cavity, from being unduly pressed against each other in the extensive motions of the joint ; and it gives a more extended, and therefore a more secure attachment to the tendon of the biceps.\nb. The articular surfaces are invested with cartilage of incrustation, which, in accordance with a very general rule, is much thicker at the centre of the convex head of the humerus\n* Trait\u00e9 des Maladies Chirurgicales, tom. iv. p. 176.\nf Essay on Fractures, &c., p. 203. Dublin, 1848.","page":573},{"file":"p0574.txt","language":"en","ocr_en":"SHOULDER JOINT \u2014 (Normal Anatomy).\n574\nthan at the circumference ; whilst the reverse is true of the glenoid cavity, the cartilage being there of greater depth at the circumference than at the centre.\nThe anatomical disposition of (c.) the synovial membrane, can be more conveniently studied after the ligaments have been examined.\n3. Connecting Media. Capsular ligament.\u2014 This is a fibrous expansion which in its general character resembles the capsular ligament of other articulations. The capsule of the shoulder joint is remarkable for its capaciousness, and consequent laxity\u2014an arrangement which permits the great freedom of motion enjoyed by this articulation. It embraces the margin of the glenoid cavity above, and is prolonged upon the tuberosities of the humerus interiorly ; hence it may be described as a sac having two apertures, of which the lower is by far the larger. Viewed externally, its form is that of a hollow cone, the base of which is placed inferiorly. The fibres which compose the capsule are extremely irregular in direction, nor are they of uniform strength or thickness. The capsule is very thin, posteriorly and also internally ; in the latter direction, it is almost aways deficient, so that the cavity of the joint is continuous with that of the synovial bursa, beneath the tendon of the subscapularis muscle ; more rarely, an opening in the capsule establishes a communication between the serous cavity of the shoulder joint and a bursa under the infra-spinatus muscle. The capsule possesses considerable strength anteriorly and above, being there reinforced by a thick bundle of fibres, sometimes described as a distinct ligament, under the name of coraco-humeral, or accessory. These fibres are attached superiorly to the under surface of the coracoid process, they thence follow an oblique course downwards and outwards, become incorporated with the proper fibres of the capsule, and are traceable inferiorly to the great tuberosity of the humerus, crossing anterior to its bicipital groove. Inferiorly, or towards the region of the axilla, the capsule possesses much intrinsic strength, though here totally devoid of any muscular or tendinous coverings. When the arm is much abducted, the head of the humerus presses strongly against this part of the ligament, which sometimes gives way, and the head of the bone escaping from the glenoid cavity, between the subscapular muscle, and the long head of the triceps, dislocation into the axilla is produced. In this accident, the head of the humerus generally detaches the subscapular muscle from the bone, and lies between that muscle and the subscapular fossa. The anatomist will not fail to observe that the subscapular nerve, as it runs from the brachial plexus outwards, to wind round the neck of the humerus, is closely related to this portion of the capsule which may be seen from the axilla, between the triceps and subscapularis muscles ; and can, therefore, easily understand why the nerve in question should be sometimes torn or compressed, when the head of the humerus has been dislocated\ndownwards and inwards ; this complication of the axillary dislocation gives rise to paralysis of the deltoid muscle, partial or complete, temporary or permanent, according to the degree of injury which the nerve may have sustained.\nThe exterior of the capsular ligament is in close relation superiorly with the supra-spinatus, and posteriorly with the infra-spinatus and teres minor muscles ; inferiorly, it is connected with the scapular origin (long head) of the triceps; whilst anteriorly, it is covered and partly replaced by the subscapularis. With the intervention of the capsular muscles, it is also related on its external, anterior, and posterior aspects to the deltoid muscle, and above to the coraco-acromial triangle. A large bursa is situated beneath the deltoid, and separates this muscle from the exterior of the capsule; it also gives an extensive investment to the tendons of the capsular muscles, and is evidently designed to favour the very free motions which those parts enjoy.\nThe long tendon of the biceps, placed! exactly upon the anterior aspect of the bone, escapes from beneath the lower edge of the capsule, which here arches across the bicipital groove, and converts it into a canal ; the capsule is not therefore perforated by the tendon of the biceps, as is stated by many anatomists. A portion of the synovial membrane descends with the tendon below the edge of the capsule, is again reflected on the groove, and so re-ascends into the joint, having formed a small \u201c cul-de-sac,\u201d without the articulation.\nFrom these relations with the surrounding muscles, the capsule derives much of its strength : the tendons of the four capsular muscles are inseparably united to the fibres of the ligament, which are prolonged inferiorly, as far as the lowest portion of the humeral tuberosities; posteriorly, it derives some fibres from the triceps ; and from the upper edge of the tendon of the great pectoral muscle, (at its insertion into the anterior lip of the bicipital groove,) a fibrous fasciculus ascends, and likewise becomes identified with the capsule ; this prolongation has been described, under the name of \u201c suspensory fraenum,\u201d by Winslow.\nIt must be obvious from this description, that the capsular ligament alone cannot maintain the bones of the shoulder joint in opposition : from its great laxity, it permits a considerable separation of the osseous surfaces, and they are maintained in contact with each other mainly by the tonic contraction of the surrounding muscles (which are placed in the most favourable position to accomplish this important object). Accordingly, in paralysis of the upper extremity, the limb becoming elongated, one or two fingers can be pressed into the joint towards the glenoid cavity, now abandoned by the head of the humerus ; and, owing probably to a somewhat similar condition of parts, spontaneous dislocation of the humerus has been known to occur in the debilitated state of the sys-","page":574},{"file":"p0575.txt","language":"en","ocr_en":"SHOULDER JOINT -\ntem consequent on the administration of mercury. Neither must the influence of atmospheric pressure be forgotten, which, exerting as it does a force of nearly fifteen pounds on the square inch, must powerfully contribute to preserve the contact of the articular surfaces.\nWithin the capsular ligament, and at the upper and outer part of the joint, two structures are found, which may, with propriety, be described as inter-articular ligaments; these are the tendon of the long head of the biceps, and the gleno-humeral, or Flood\u2019s ligament.\nThe long tendon of the biceps has been described already, as attached to the apex of the glenoid cavity, and to the fibrous portion of its circumferential fibro-cartilage. Surrounded by synovial membrane, it passes downwards and outwards, forming an arch over the head of the humerus, it then descends in the bicipital groove, where it is retained in situ by the fibres of the capsular, and of the accessory (coraco-humeral) ligaments.\nCruveilhier mentions that in two cases he found this tendon united by a strong adhesion to its groove, \u201c thus justifying the name of \u2018 inter-articular ligament:\u2019 the tendon for the long head of the biceps took its origin from the same groove.\u201d This condition, Cruveilhier supposes to have been the result of injury; but as the appearance in question has been seen by the writer, as the result of chronic rheumatism, affecting the scapulohumeral articulation, he is compelled, although reluctantly, to dissent from such high authority, and to express his opinion that this change originated in rheumatism, not in accident; his opinion is farther borne out by the state of the inter-articular portion of the tendon in Cruveilhier\u2019s cases, for it is stated, that \u201c the bicipital groove was depressed, and the inter-articular ligament flattened, and, as it were, lacerated.\u201d\nThe inter-articular portion of the tendon of the biceps, by itself, could scarcely protect the head of the humerus from displacement upwards, a use very commonly assigned to it, as the smooth convex head of the bone would readily slip from beneath it ; but in the interior of the joint, a second band, the \u201c gleno-humeral ligament,\u201d described by the late Dr. V. Flood, is thrown across the head of the humerus, and may contribute to oppose this luxation ; we quote the following description of this ligament from Dr. Flood : \u2014 \u201c It may be easily exposed,\u201d he says, \u201c by cutting through the inferior part of the capsule transversely, and throwing back the arm over the head, you thus expose the interior of the upper part of the capsule, also the biceps tendon. Parallel to the inner edge of the latter, this ligament may be felt and exposed by a little dissection. The tendon of the sub-scapularis in passing to its insertion, rests in a notch in the superior and internal part of the edge of the cavity; from the edges of this notch, the ligament arises broad and flat, then proceeds along the internal edge of the biceps tendon, and becoming smaller and\n- (Normal Anatomy).\t575\nrounder, is inserted into a distinct pit in the anatomical neck of the humerus, at the inner edge of the bicipital groove. In its triangular form, its origin at a notch in the articular fossa, and its insertion into a pit, it strongly resembles the \u2018 ligainentum teres \u2019 of the hip-joint.\u201d*\nIn nearly all the specimens examined by the writer, the upper half of this ligament had both its surfaces invested by the synovial membrane. This enables the dissector readily to distinguish it from the capsule ; but in-feriorly, its fibres are generally identified with this structure, and therefore it loses the appearance of a distinct ligament, before arriving at the humerus.\nWith the mode of its origin, and its intra-capsular position, all resemblance between this structure and the \u201c ligamentum teres \u201d in the hip-joint, ceases ; the latter has little of the structure, and fulfils none of the uses of a ligament. Not so the \u201cgleno-humeral ligament:\u201d its structure is distinctly fibrous, it possesses great powers of resistance, and it is an auxiliary to the tendon of the biceps, so that both together are enabled to restrain the undue ascent of the humerus ; an object which it seems probable neither of them could accomplish, unaided by the other.\nSynovial membrane. \u2014 In its arrangement and general characters, the synovial membrane of the shoulder joint differs in no way from that of other articulations. As the fibrous capsule is lax, so the serous membrane, which lines it, presents a cavity of large size. Having covered the articular cartilage of the head, it passes downwards on the neck and tuberosities of the humerus, as far as the lower attachment of the capsule, to the inner surface of which it is thence reflected : having lined the capsule, the synovial membrane arrives at the glenoid cavity, the articular surface of which it similarly invests ; it forms sheaths for the inter-articular ligaments, for the long tendon of the biceps, and for the glenohumeral ligament : that for the former, as has been already described, extends along the bicipital groove, even beyond the limits of the capsule. Internally, where the capsule is deficient, the synovial membrane covers the corresponding portion of the tendon of the subscapularis, and here a communication is established between the cavity of the serous membrane of the articulation and that of the bursa mucosa, which is found beneath that muscle. A similar communication sometimes exists posteriorly between the cavity of the joint and the bursa, which is subjacent to the infra-spinatus muscle. A few fatty folds are generally found attached to the reflections of the membrane.\nIn connection with the scapulo-humeral articulation, the remarkable vaulted arch placed above it remains to be described. This is constituted by the acromion and coracoid processes, and the intermediate ligament. It may be regarded as supplemental to the\n* Lancet, 1829-30, p. 672.","page":575},{"file":"p0576.txt","language":"en","ocr_en":"576\tSHOULDER JOINT\nshoulder joint, and as being intended to compensate for the incomplete reception of the head of the humerus by the glenoid cavity. The centre of this arch is formed by the coraco-acromial or triangular ligament, of which the apex is situated at the acromion, and the base at the outer edge of the coracoid process. The ligament consists of two bundles, separated by a cellular interval, and placed more anteriorly the one than the other. The acromion and coracoid processes constitute respectively the extremities and the points of support to the arch, whilst its under surface is accurately adapted to the convexity of the head of the humerus, the tendon of the supra-spinatus muscle intervening. The existence of the large bursa (elsewhere noticed) between this tendon and the coraco-acromial ligament, abundantly proves that considerable motion takes place between them : the upper surface of the ligament is concealed by the deltoid muscle.\nIn this arrangement may be recognised a provision for protecting the shoulder-joint against violence from above (Voute protec-tatrice, Blaudin), and the humerus against displacement from below, either directly upwards or with an inclination backwards or forwards. And for such a provision there is the greater necessity, as the upper extremity is constantly exposed to forces which act upon it from below.\nMechanical functions. \u2014 In common with other enarthrodial articulations, the shoulder joint enjoys the following varieties of motion :\n1.\tFlexion ; 2. extension; 3. adduction; 4. abduction ; 5. circumduction ; and 6. rotation.\n1.\tOf the opposed motions of flexion and extension, the former possesses the greater latitude. When carried to its utmost extent, the humerus appears to move through the arc of half a circle of which the centre is at the joint ; for the arm from being parallel to the trunk in the direction downwards, may by this motion be raised vertically upwards.\n2.\tExtension, on the other hand, is much more limited, being restrained by the great strength of the anterior portion of the capsule, by the inter-articular ligaments, and by the contact of the head of the humerus with the coracoid process, which are all calculated to check the advance of the head of the humerus, the necessary result of extension.\nFlexion and extension, although apparently performed in the scapulo-humeral articulation solely, are' really distributed over a much more extended sphere, being shared by the scapula, and by the articulations of the clavicle with the acromion and with the sternum.\nWhen extreme flexion or extension takes place, the scapula undergoes a motion of rotation upon its axis (an imaginary line passing through the centre of the bone) ; and the result is, that when the humerus is flexed the superior angle of the scapula moves backwards, and its inferior angle forwards ; whereas, in extension of the arm, a change of position the reverse of this is produced in the scapula. This rotation of the scapula is favoured by\n\u2014 (Normal Anatomy).\nthe looseness of the ligamentous connections of the acromio-clavicular articulation, whilst it is restrained within bounds by the coraco-clavicular ligaments (conoid and trapezoid). The trapezoid limits the advance of the upper angle of the scapula ; the conoid checks the rotation which would carry it in the opposite direction.\nThe muscles which chiefly effect the rotation of the scapula are, the trapezius, latissimus dorsi, levator anguli scapulae, rhomboid ei scapulae, serratus magnus anticus, and the pectoralis minor. Of these the trapezius and serratus magnus rotate the scapula, so as to elevate its acromial end ; whilst the rhomboidei muscles and the pectoralis minor produce the contrary effect ; the latissimus dorsi can only act on the scapula when it takes an origin from its inferior angle. If it were possible for the levator anguli scapulae to act independently of the other scapular muscles, it would depress the acromion ; but as this rarely, if ever occurs, its ordinary action is to assist those muscles which elevate the entire scapula, and, consequently, the shoulder joint.\n3.\tThe motions of adduction and abduction are remarkably contrasted : the former can hardly, with strict propriety, be said to exist, being prevented by the immediate contact of the arm with the side ; adduction, however, in an oblique direction forwards and inwards, is permitted. This motion is limited by the projection of the thorax : when the arm is placed in this position the head of the humerus is strongly pressed against the posterior portion of the capsule, and if force were to be applied to the distal extremity of the lever under these circumstances, dislocation backwards might be produced.\n4.\tThe motion of abduction is the most extensive of those enjoyed by the shoulder-joint; it permits the separation of the arm from the side, until it becomes parallel to the trunk in a direction upwards ; flexion has been stated to be capable of the same range, but the latter owes much of its freedom to the mobility of the scapula, whereas in abduction the scapula moves but little, and nearly all the motion takes place in the scapulohumeral articulation.\nAbduction is limited by the contact of the neck of the humerus with the acromion, and by the resistance of the capsular ligament. When fully performed, the head of the humerus revolves in the glenoid cavity, and in its descent presses strongly against the inferior portion of the capsule ; if force be now applied to the upper extremity from above, the ligament may give way and dislocation be effected. More frequently this accident occurs when the arm is moderately abducted, and the mechanism bj which, under such circumstances, it is effected, may be briefly explained. When a person falls on the inside of the elbow, while the arm is abducted, the upper extremity represents a lever of the third order, of which the fulcrum is at the point of contact of the elbow with the ground, and the power at the \u201c folds of the axilla ; \u201d the at-","page":576},{"file":"p0577.txt","language":"en","ocr_en":"i\nJ\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t577\ntachment of these muscles at right angles to the lever, and at a considerable distance from the fulcrum, enables them to act at a great mechanical advantage, and their sudden contraction makes the upper end of the humerus to become the moveable extremity of the lever, and presses it against the capsule, which giving way between the triceps and the sub-scapularis muscles, allows the bone to escape into the subscapular fossa. The long diameter of the glenoid cavity being vertically placed is favourable to the motion of abduction, and in some degree lessens the liability to dislocation, to which the joint is so prone in this position, whilst on the other hand the comparative fixity of the scapula when the arm is being abducted, explains in some degree the frequency of dislocation of the humerus downwards.\n5.\tCircumduction is compounded of the preceding motions, the flatness of the humeral tuberosities and the shallowness of the glenoid cavity rendering it very extensive in subservience to the variety of uses of the upper extremity. Circumduction is much more limited in the hip-joint, as there, the anatomical conditions which favour this motion in the shoulder are wanting, freedom of motion being sacrificed to security.\n6.\tRotation is imperfectly developed in the shoulder joint, but it exists in great perfection in the hip, as a necessary consequence of the great development of the neck of the femur.\n{Ben. Geo. JSBDowel?)\nSHOULDER JOINT, Abnormal Conditions of.\u2014The alterations from the normal condition of the shoulder joint, which we have observed, may be classed under the three following heads : \u2014 First, those which are produced by disease ; secondly, those caused by accidental injury; and, thirdly, those which are the result of congenital malformation.\nSection I. \u2014 Disease. \u2014 The abnormal appearances observed in the joints in general, and in that of the shoulder in particular, resulting from disease, owe their origin to some local injury done to the joint, or to some specific irritation, such as gout, rheumatism, syphilis, struma, &c. Whether the disease first commences in the bone, the cartilage, or synovial membrane*, it soon involves all the structures of the articulation in the same morbid action, and with the local affection is usually associated some form of inflammation, either acute or chronic.\nAcute arthritis of the shoulder.\u2014The symptoms of acute inflammation of the shoulder joint will be found to be similar to those we have elsewhere in this work described as being present, when some of the other large articulations have been affected by it.f The patient will feel considerable pain in the shoulder joint, to the front of which he will point as the seat of his most acute suffering. This pain is aggravated by the slightest touch,\n* See Hip Joint, Yol. II. p. 790.\nf See Yol. III. pp. 49\u201455 ; Hip Joint ; also Yol. II. pp. 788\u2014792.\nVOL. IV.\nor when any movement is communicated to the joint. The patient himself carefully preserves his arm immovably in one posture as he lies in bed, with his elbow abducted from his side, and his hand supported in the state of supination. Effusion of altered synovia, or purulent matter, rapidly takes place into the synovial sac of the articulation. There is much heat of the surface and tension of the skin. The pain which, as already mentioned, is felt on the front of the shoulder joint, soon extends down the arm to the inside of the elbow-joint, and the patient complains of spasmodic startings of the limb, and oedema of the whole extremity may supervene. The distention of the synovial sac of the articulation increases, and the surgeon can discover a fluctuation along the anterior or posterior border of the deltoid region, and he may find it expedient, with the view of relieving pain and tension, to make an incision into the joint, and thus give exit to a large quantity of purulent matter. Irritative, or it may be in some constitutions inflammatory, fever accompanies these symptoms, and the patient may be carried off even before the period when the purulent matter shall have made its way to the surface ; or the acute inflammation may subside into chronic arthritis, and articular caries of the shoulder joint be established, to run its subsequent course as a chronic disease.\nThe acute form of the disease only differs from the chronic in the former being more intense in its attack, and in being accompanied with swelling of the joint \u2014 in being more rapid in its course, and more speedily producing complete disorganisation of the articular textures.\nAnatomical characters of arthritis of the shoulder\u2014Very few opportunities are offered to the anatomist of witnessing the appearances which the several tissues of the shoulder joint present when they have been the seat of acute inflammation ; we may, however, safely infer, that the articular structure of this joint will be altered in a similar manner in consequence of an attack of acute arthritis, as the corresponding tissues in other joints have been already described.*\nChronic arthritis of the shoulder.\u2014 We meet, in practice, with twoforms of chronic arthritis of the shoulder. The first of these occurs as an example of slow inflammation passing into either articular caries or anchylosis of the joint, and is analogous to the well-known scrofulous disease of the hip. The second furnishes us with a specimen of a chronic disease, which the writer has elsewhere in this work denominated chronic rheumatic arthritis f ; a disease, the effects of which are to be traced in all the articulations, but its peculiarities are in no joint better exemplified than when the shoulder becomes the seat of it. We shall first treat of the abnornal appearances produced by the disease we call\n* Yide Yol. III. p. 54.\n\u2022f See Hand; Hip Joint; Elbow, &c. &c,\np P","page":577},{"file":"p0578.txt","language":"en","ocr_en":"578 ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nsimple chronic arthritis of the shoulder ; secondly, we shall describe those which belong to chronic rheumatic arthritis of the same articulation.\nWhile the two chronic diseases of the hip, namely, the scrofulous affection and the chronic rheumatic arthritis of this joint, have of late years attracted much attention from the profession, it appears to the writer of this article that the corresponding diseases of the shoulder joint have been much overlooked. He hopes, therefore, he shall be excused if he deems it necessary to enter into more than ordinary details relative to the two chronic affections of the shoulder joint, which he will now endeavour faithfully to delineate.\nSimple chronic arthritis of the shoulder may be the result of a sprain or contusion : the synovial and fibro-synovial structures are in this case principally affected. If, however, the inflammatory action be not arrested, the bones, as well as their cartilaginous incrustations, become ultimately engaged, and true articular caries is established. The disease sometimes begins in the shoulder joint, without the patient being able to assign any cause for it ; and in this case it may have a constitutional origin, and be the result of struma, or acute rheumatism, which last having subsided in the other joints, has concentrated itself on this one articulation, assuming the form of an articular caries. We have known it also appear in ,a young female during the convalescence from a long-continued gastric fever.\nSymptoms,\u2014The first symptoms the patient suffers from, who is affected with simple chronic arthritis, or articular caries of the bones which enter into the formation of the shoulder joint, is a sensation of weight, weariness, and aching in the affected arm. These signs of the disease are at first not constantly present ; they appear and then disappear, to return again in some days. Some stiffness in moving the affected arm is next complained of, to which is soon added pain, which the patient says is deeply seated in the joint, and which is augmented by using the articulation, or when the articular surfaces are pressed against each other. These symptoms are seldom so severe as to prevent the patient from following his ordinary occupations.\nSo far the disease may be said to be merely in its commencement ; but very soon we observe it to pass into the second stage, when it may be discovered, on minute inquiry, that there is some sympathetic disturbance of the system \u2014 some heat of skin and slight acceleration of the pulse.\nOn examining the affected joint, we observe that the patient habitually carries it higher than the opposite shoulder, and the clavicle at the affected side is observed to pass, as it were, obliquely upwards and outwards, the adipose and cellular tissue, as well as all the muscles around the shoulder joint waste. The deltoid muscle, in a state of atrophy, appears stretched longitudinally, and the affected shoulder to have lost much of its\nnormal roundness. The acromion process projects (see fig. 427.), and the arm of the affected side appears, and is usually found, on comparative measurement, to be really lengthened; the anterior fold of the axilla is deepened by the descent of the humerus from the glenoid cavity. The pain increases, and extends downwards from the shoulder to the inside of the elbow and wrist.\nIn the third period of the disease, the wasted condition of the muscles around the shoulder joint, as well as those of the whole upper extremity, becomes still more obvious, and now the arm, which was really longer than natural, becomes gradually shorter. It is quite possible that, after the limb has become shortened, any pain or uneasiness felt in the joint may subside, and a process of true anchylosis be established before suppuration takes place ; but it much more frequently occurs, that about the time of the shortening of the limb, or subsequently, a chronic symptomatic abscess will make its appearance, and perhaps open spontaneously, in the axilla, or on some point along the outline of the deltoid, or inferior margin of the pectoral muscle ; and then the disease may be said to be in the fourth stage.\nThis very serious chronic disease of the shoulder may be sometimes arrested in its early stage, and the patient recover the use of the joint; but, on the other hand, the disease frequently ends unfavourably by hectic fever, with its fatal consequences supervening. The more usual course for the disease to run will be found in general to be, that suppuration will tak e place, abscess after abscess will form, their purulent contents escaping and continuing to flow, greatly exhausting the strength and spirits of the patient ; but under the influence of good air and judicious management, the discharge from the abscesses may cease, the constitution improve, and true bony anchylosis of the shoulder joint be established.\nThe history of the two following cases of simple chronic arthritis of the shoulder, at this moment (June, 1848) under treatment at the Richmond Hospital, will serve to illustrate some of the preceding observations as to the symptoms which patients usually labour under when affected by this chronic disease.\nCase 1. Chronic arthritis of the right shoulder joint of four years' duration. The disease in the second stage. \u2014 Margaret Moore, \u00e6t. 27, servant, admitted March 8th, 1848, under the writer\u2019s care. She complained of stiffness and weakness of her right shoulder (fig. 427.), and of pain, which was much worse at night than during the day ; she had also a constant uneasiness at the inner side of the right elbow, and her nights were restless, her sleep interrupted by spasmodic starting of the whole limb, and pain extending down to the wrist and back of the hand ; she states that she has really more pain in the elbow and wrist than in her shoulder, and that these pains are increased when the arm is moved, or the articular surfaces are pressed against each other. When-","page":578},{"file":"p0579.txt","language":"en","ocr_en":"579\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\never she moves her arm in the slightest degree the scapula follows the humerus, so\nFig. 427.\nCase of M. Moore : Articular caries of the right shoulder joint ; second stage of the disease.\nthat in the voluntary movements of the upper extremity really no motion takes place in the shoulder joint ; but if we grasp the scapula, and thus firmly fix it, and at the same time move the humerus, a distinct crepitus is occasionally elicited, of which the patient herself also is conscious. When the arm is permitted for a moment to hang down by her side unsupported, she has great pain, and she feels the advantage of\u2019keeping it constantly in a sling, with her hand as high as her opposite collar bone. The muscles surrounding the right shoulder joint were observed to be in a wasted condition ; this shoulder seemed higher up than the other, and the clavicle of this side to have a corresponding obliquity., The history she gives of the origin and progress of this disease is, that she has had a certain degree of pain and uneasiness in the articulation for the last four years, but that it never swelled much nor became inflamed, nor did it prevent her from follow-, ing her occupation as housemaid, until three months ago, when she felt compelled to give up her situation. She referred the aggravation of her distress latterly to an injury the joint received from a severe fall she got down an entire flight of stairs. The latter circumstance in the history of her case made us more particular in our inquiries as to whether any fracture or dislocation could have occurred at the moment of this accident, and have been left unreduced. We were readily satisfied that there had been no fracture, as the affected arm was longer than the other.\nThe deltoid muscle was flattened and the acromion was seen presenting an angular projection as in an old luxation ; yet the head of the humerus could be felt below the acromion; the anterior fold of the axilla was deeper than natural, but the elbow in this\nwoman was placed habitually close to her side, and the long axis of the humerus could be traced by the eye to run nearly perpendicularly upwards towards the site of the glenoid cavity, and not more inwards towards the axilla, as in the case of luxation.\nThe atrophy we observed to affect the muscles in the vicinity of the diseased shoul-der joint in this case, was not confined to the deltoid and capsular muscles ;\u25a0 but the great pectoral was so much wasted that the ribs and intercostal interstices were seen conspicuously on the right side, while the corresponding spaces on, the left side of the front of the thorax were sufficiently covered by muscle, &e. The right arm and forearm were more wasted than the left or unaffected limb,, while the former extremity, measured from the acromion to the outer condyle of the humerus, shows an addition of length, or rather a descent of the humerus from the glenoid cavity, for the-space of one inch. This woman has been subjected, to the ordinary treatment for such cases she feels the necessity of supporting her arm, and not allowing it out of the sling, during the day, while she walks in the open air.\nThe foregoing case presents us, as we have said, with a good specimen of the simple chronic arthritis, or articular caries of the shoulder in the second stage of the disease. It is probable that a slow process of bony an-, chylosis will be ultimately established ;. and the woman after a time may lose all pain, regain her-general-health, and ultimately recover, but with the impediment which must evqr attend an an-chylosed shoulder joint. The course of the disease is not always so favourable ; on the contrary, when the disease has arrived, as in the case of Moore just related, at the second stage, the pain is in some instances increased, the head of the humerus becomes wasted by caries as well as the surface of the glenoid cavity, when it will be found that the affected extremity, which was really longer than the other, shall have become shorter. This shortening, which marks the third stage of the disease, is frequently thought to be the result of complete dislocation ; but this occurrence, the possibility of which we do not deny, we believe, however, to be exceedingly rare. The shortening may be the consequence of caries and absorption of the head of the humerus, as well as of the surface, of the gle-. noid cavity. Under such circumstances the head of the bone may lean towards the axilla and subscapular fossa, or backwards towards the dorsum of the scapula ; or it may be elevated, so as to ifeaeh the concavity of the coraco-acromial vault, and be maintained there by the tonic force of the elevator muscles ; but we have not found it completely dislocated as a result of caries,\nCase 2. Articular caries at the shoulder joint in the fourth stage of the disease. \u2014 Mary Ann Malloy, \u00e6t. 21, servant, admitted into the Richmond Hospital 25th July, 1847, under the care of Dr. Hutton. She has been now (June, 1848) eleven months","page":579},{"file":"p0580.txt","language":"en","ocr_en":"580\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nin hospital, and her left shoulder joint has in this period gone through all the stages of chronic arthritis ; and a process of anchylosis, with shortening of the left upper extremity, appears to have been nearly completed. Her general health seems at this time but little affected : several depressions along the margins of the deltoid muscle, anteriorly and posteriorly, mark the situation of the numerous openings, most of which are now closed, through which purulent matter had escaped from the joint. The history which we collected of her case was, that about two months previously to her coming to the hospital she fell backwards on her left elbow, to which accident she ascribes her disease ; that subsequently to this fall she felt pain in her left shoulder, but she cannot recollect that the joint swelled or became hot ; on the contrary, the shoulder always seemed to her, from the first, to waste, and to be colder (as it is at this moment) than the other ; except when the period of the formation of the abscesses arrived. She states that the movements of the joint, -during the progress of the disease, were most painful, and that she had a sensation of something grating in the joint whenever the surgeon, in examining it, moved the arm. The arm is half an inch shorter than the other, and is closely approximated to the side : whenever abduction, flexion, or extension of it is attempted by the patient, the scapula invariably moves also. The patient has no power of rotation of the head of the humerus on the scapula, nor \u00c6an any movement of the kind be communicated. The head of the humerus in this case has not been dislocated, but its tendency is certainly backwards towards the infraspinatus fossa, where some fulness is perceived. The partial absorption of the head of the humerus, as well as the removal of a portion of the surface of the glenoid cavity by caries, which we believe has occurred here, will sufficiently account for the shortened condition of the arm.\nThe most favourable prognosis we can form as to this case is, that a bony anchylosis of the shoulder joint will be established.\nIn the first of these cases (M. Moore) it was very manifest that the limb was elongated; and in this second ease (Malloy), when the disease of the shoulder joint had arrived at a much more advanced stage, it was equally evident that the length of the affected extremity was diminished. We have adduced these cases as examples of what may be frequently expected to be seen by those who watch the course of articular caries of the shoulder joint ; but we must be prepared to meet with examples in which it may be observed, that during the whole progress of the disease the length of the limb will be neither increased nor diminished. Varieties analogous to this we notice in the symptoms and progress of articular caries when it affects other joints (see Hip Joint); and therefore we need not be surprised, when the shoulder joint is the seat of chronic arthritis, that sometimes\nthe extremity of the affected side is shorter, sometimes longer, and that sometimes during the whole course of the disease but little alteration as to increase or diminution of length is appreciable.\nAnatomical characters of chronic arthritis of the shoulder.\u2014The specimens we have an opportunity of examining anatomically, which show the ultimate effects of chronic arthritis on the several structures composing the shoulder joint, cannot be considered very rare ; but it must be confessed that we seldom can ascertain the condition of the different structures of the shoulder joint which have been affected by chronic arthritis, excepting in cases in which the disease has arrived at its last stage, and has been the cause of the death of the patient. On making the post-mortem examination of the affected shoulder in cases where the disease has arrived at its last stage, we usually notice that the skin has been perforated by numerous fistulous openings ; these are sometimes to be seen in the axilla, or ranged along the line of the margin of the deltoid muscle, perhaps at points more distant from the joint, as on the lower margin of the pectoral muscle near the mamma (case of Malloy). The subcutaneous cellular structure we have not found infiltrated, as it is in cases of white swelling of the knee, or of the other joints, with a gelatinous glairy matter; on the contrary, the cellular structure itself has always seemed to us to be in a wasted condition, containing no adeps ; the deltoid as well as the articular muscles have been found in a state of atrophy. The bursa underneath the deltoid muscle has been observed to have been the seat of an effusion of fluid, quite distinct from that contained within the capsule of the joint ; the internal surface of the bursa as well as the synovial lining of the fibrous capsule have been also found coated with lymph.\nSometimes in advanced cases the fibrous capsule has been found much contracted as well as thickened, and having numerous perforations in it, which had been the internal orifices of several fistulous canals, which having opened externally had acted as excretory ducts, as it were conducting purulent matter from the different points of the carious surfaces of the bones of the joint, and even from the centre of the diseased head of the humerus. In all of the advanced cases that we have examined, the tendon of the biceps, so far as its intra-articular portion is concerned, has been' removed. The articular surfaces have been always divested of their cartilaginous incrustations, and the reticular structure of the head of the humerus, and of the scapula where it forms the glenoid cavity, usually exposed and bare sometimes coated with a layer of puriform lymph. Part of the head of the humerus has been removed, and in what remains of it deep digital depressions have been observed,and foramina, which penetrate even into the centre of the head of the bone.\nM. Bonnet, of Lyons, states, \u201cthat on making the post-mortem examination of one","page":580},{"file":"p0581.txt","language":"en","ocr_en":"581\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nof his patients, who died of articular caries of the shoulder joint, he discovered, when a vertical section was made of the humerus, that in the centre of the head of this bone there was contained a cavity or cell, the size of a hazel nut, filled with tubercular matter, in the middle of which were found fragments of necrosed particles of bone. In this case also, he adds, tubercular matter was found in the axillary glands.\u201d* Bony nodules and stalactiform osseous productions are observed to be produced from different parts of the scapula and head of the humerus, in the vicinity of the shoulder joint. The coracoid process and acromial end of the clavicle we have found in these cases carious ; the alterations of the osseous structure do- not seem confined to the bones in the immediate vicinity of the joint itself. The whole scapula and humerus seem specifically lighter than they should be normally. We have tried the experiment of placing the diseased bones in water, and have seen them float, while the normal bones of the same region sink. The ribs, too, have been found sometimes carious simultaneously with the bones which constitute the scapulo-humeral joint.\nThese observations refer merely to the local condition of the articular structures themselves. The state of the constitution of many of these cases affected with chronic arthritis of the shoulder deserves the attentive consideration of the physician and surgeon.\nThe prognosis to be formed as to any advanced case of articular caries of the shoulder joint should be a guarded one, as the following facts may convince us. In the first case which we shall now adduce, fatal disease of the lungs seemed coincident with the articular caries of the shoulder ; and at last it was doubtful which of the two diseases was the immediate cause of the death of the patient. In the second case disease of the brain, with paralysis, came on, and was the immediate cause of the death of the individual, who had been previously much reduced by articular caries of the shoulder.\nCase 3. Chronic arthritis or articular caries of the shoulder joint, lasting thirteen months. \u2014Matthew M'Cabe, a labourer, set. 38, was admitted into the Richmond Hospital, Sept. 2. 1846, under Dr. Hutton\u2019s care.f He stated that about nine months previously he was seized with a pain in his left shoulder, which soon extended to his elbow ; he was able to work for two months after the first attack of pain, but after this period the arm became stiff^ and remained powerless by his side ; the muscles around the shoulder and of the whole extremity were wasted ; fistulous openings existed beneath the coracoid process, and through the deltoid muscle ; the limb was of its normal length. When the joint was pressed the patient complained of pain ; the motion of the head of the humerus on the glenoid cavity of the scapula appeared much limited ;\n* Traite des Maladies des Articulations, f The writer is indebted to Dr. Hutton for the notes of this case.\nhe had cough and hectic fever, of which the prominent symptoms, beside the cough, were a quick pulse and diarrhoea. He died Jan. 25. 1842.\nPost-mortem examination.\u2014 The body was emaciated. Before making the examination* a plaster of Paris cast was taken of the left shoulder joint, which is preserved in the hospital museum : this shows especially the wasted condition of all the muscles around the shoulder joint, and the consequent prominence of the spine and acromial process of the scapula, usual in cases of articular caries of the shoulder. For the space of two inches along the anterior wall of the axilla and line of the humerus an oblong depressed scrofulous ulcer existed, in which were seen the orifices of three or four fistulous canals, which led from the interior of the joint. The elbow was placed somewhat backward, and the long axis of the humerus was consequently directed from below upwards and forwards ; the convexity of the head of the humerus, without being dislocated, was placed somewhat more forwards and inwards than natural. Upon removing the deltoid muscle, which was wasted and perforated by fistulous openings, it was found that the capsular ligament was contracted and thickened, and had several openings in it* and that purulent matter was effused both into the joint and under the deltoid muscle, which thus formed the sac of an abscess. The cartilages had been entirely removed from the articular surfaces. The intra-capsular portion of the tendon of the biceps had disappeared ; the highest part of this tendon which remained was attached to the inside of the capsular ligament. The bones had been injected with size and vermilion, and presented in their interior as well as on their carious surfaces a reddish colour; but they did not appear softened; when after maceration they had been dried, they seemed to be preternaturally light. The. superior hemispherical portion of the head of the humerus had been removed very nearly to the level of the anatomical neck, or situation for the attachment of the capsules ; and the surface was red, porous, and much roughened from caries. Towards the highest part of the humerus, just within the line which separates the great tuberosity from the head of the humerus, there existed two very deep digital or alveolar depressions, which pene-. trated into the cellular structure of the head of the humerus : the anterior part of the upper-extremity of this bone, where the bicipital groove exists, was rough and porous ; the groove was much deepened, particularly in the situation of the lesser tuberosity, which was elevated into a bony nodule, and enlarged about one inch below the lesser tuberosity. On the front of the surgical neck there existed another bony nodule, but smaller.\nThe surface of the glenoid cavity seemed to have been somewhat worn away and rendered more than naturally concave ; the anterior or inner margin of it was rounded off by caries, The oval outline of the glenoid cavity was elongated from above downwards, and somewhat","page":581},{"file":"p0582.txt","language":"en","ocr_en":"582\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nnarrowed transversely. The axillary margin of the scapula, where the long head of the triceps arises, was furnished with the friable stalactiform osseous productions, which we have already noticed to have existed around the articular surfaces of all the other articulations, when they had been for a long time the seat of strumous arthritis, or scrofulous caries of the joint.* The rest of the scapula had a rough scabrous aspect ; the coracoid process presented the appearance also of having been in a commencing state of caries. The external lamina of the bone had been absorbed; the exposed reticular structures of it were so friable, they would crumble under the slightest pressure..-]'\nThe lungs presented the ordinary appearances of phthisis in its last stage ; there were tubercles and tubercular excavations in both lungs.\nIn this case the disease of the shoulder joint seemed to have arrived at its last stage, and to have been in itself sufficient to have induced a fatal hectic fever. However, coincident with the articular caries appeared the .disease of the lung, which caused, or at all events hastened, the death of the patient.\nCase 4. Articular caries of the shoulder in the fourth stage, \u2014Edward Brady, \u00e6t, 36, a baker, was admitted into the Richmond Hospital, 6th of May, 1828, labouring under disease of the right shoulder joint. It appeared that he had had for some time previously a chronic inflammatory affection of this articulation, for the origin of which he knew no cause ; that an abscess had formed, and that matter had made its waj' through the skin just beneath the point of insertion of the pectoralis major into the humerus, where a fistulous aperture existed, which daily gave exit to a considerable discharge of purulent matter. On admission into the hospital, the right shoulder joint was swollen, the man was emaciated and in a state of debility, his pulse quick and weak ; he complained of pain when the slightest pressure was made on the joint, or motion communicated to it. From the short notes of the patient\u2019s symptoms during the two last months of his life when in hospital, we learn, that after five weeks\u2019 treatment, such as local bleeding and counter-irritations, as blisters, &c., he was not really better. On the contrary, \u201c the patient was much debilitated, the hectic symptoms had increased, the shoulder was flattened, the motions of the joint were circumscribed within very narrow limits, the acromion was prominent as in axillary dislocation.\u201d In another month, viz. July 12, we find entered the following report:\u2014 \u201c No improvement either locally or constitutionally ; the shoulder is more emaciated, and a crepitating, grating sound is elicited on rotating the humerus ; the hand is * Vide Hip Joint, Abnormal Condition of, Vol. II. p.794.fig. 311. j- Museum, Richmond Hospital.\nI This case has been extracted from the case book of the late Dr. Macdowell, whose accuracy of observation and fidelity were well known to the editor of this work as well as to the writer.\nslightly cedematous, yet the discharge is less profuse, and considered of a more healthy appearance.\u201d Eight days subsequently to this report the patient became comatose, and died in the course of a few hours.\nPost-mortem examination. \u2014 The subcutaneous eellular structure which covered the deltoid muscle of the affected side was destitute of all adipose tissue ; the deltoid was pale and thin ; the sub-deltoid bursa contained a sanious fluid, which being removed it was seen that the bursa had been lined with lymph ; the fibrous capsule, ulcerated at one point, was thickened, as was the synovial membrane, which was pulpy ; the articular cartilage was entirely removed from the head of the humerus and surface of the glenoid cavity of the scapula. The superior extremity of the former was almost totally destroyed, the bone having been crumbled down into many small portions. The surfaces were covered with unhealthy looking pus and lymph. The long tendon of the biceps had \"disappeared ; the surface of the glenoid cavity was carious ; the small muscles about the joint resembled the deltoid as to the state of thinness and atrophy they had been reduced to. The sinus leading to the point in the axilla already mentioned was lined with lymph.\nThe disease of the shoulder joint in this case, it appears, had, as in the preceding, arrived nearly at its last period, and we might have supposed that the morbid state here described of so important an articulation was of itself sufficient to cause a fatal result, when the affection of the brain suddenly supervened, and became the immediate cause of the death of the patient.\nIt were very desirable that we could assign to the four periods of this disease of the shoulder joint, when affected by chronic arthritis, the anatomical characters which belong to each stage respectively ; but we repeat, we are as yet only truly acquainted with those appearances which the post-mortem examinations exhibit of the ultimate result of the disease as it has affected the articular textures, when it has been the cause of the death of the patient.\nThe pathological condition, therefore, of the different tissues which enter into the composition of the shoulder joint, as they are affected in the early stages of this chronic disease, is as yet, we believe, but little known. The most remarkable features of the second stage of chronic arthritis of the shoulder joint we notice, is the descent of the head of the humerus from the glenoid cavity, and consequent elongation of the upper extremity of the affected side. This, we conjecture, may be accounted for by recollecting that the deltoid and articular muscles, which in their normal state maintain the head of the humerus close up against the glenoid cavity, are now in a state of atrophy. They have from want of use, and perhaps, also, from sympathy with the diseased state of the articular structures, lost all tonic force. Although these muscles are not really paralysed, still they seem not to have","page":582},{"file":"p0583.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t583\npower enough to resist the influence of the weight of the upper extremity ; and hence the head of the humerus, unrestrained by the naturally loose capsular ligament, descends to the extent of half an inch or an inch from the glenoid cavity. There can be but little doubt, also, that in the second period of the disease we are now considering, an effusion takes place into the interior of the synovial capsule of the joint : this may be altered synovial fluid or lymph, or purulent matter to a small amount ; but whatever the effusion be, it also will have the effect of partially displacing, and causing an elongation of, the upper extremity.\nIt may be asked how it happens that the head of the humerus, once partially displaced downwards, does not become subjected to a secondary displacement inwards, under the influence of the contractions of the pectoral and other muscles ? The answer may perhaps be, that, in the second stage of this disease, the long tendon of the biceps retains its form, place, and functions ; so long as this tendon remains in its state of integrity, arching over the head of the bone, and then passing in a perpendicular line down along the humerus, the head of this bone cannot be partially elevated above its normal situation, nor even drawn inwards or backwards by either of the great muscles which form the anterior or posterior walls of the axilla; but when the long tendon of the biceps is destroyed, as it very generally is in the third stage of this disease, then the head of the humerus may be moved in whatever, direction the inclination of the new plane formed by the altered surface of the glenoid cavity may give, or the muscles may draw it in.\nIn the third stage of chronic arthritis of the shoulder, the bones which compose the joint are carious, and their surfaces are partially and unequally removed ; the length of the extremity may be diminished. The long tendon of the biceps is removed, and hence no longer influences the position which the head of the humerus is ultimately to take, whether the bone in this third stage be partially displaced upwards, forwards, or backwards.\n\u00bb Some of the surrounding muscles are in this period of the disease in a state of atrophy, while others retain their form and functions. The proper articular muscles, whose normal function it is to keep the head of the humerus close to the glenoid cavity, are, in the third stage of disease, wasted ; and besides, as their capsular attachment is usually in this advanced stage of the disease destroyed, their influence becomes annihilated.\nThe pectoralis major may draw the head of the bone towards the median line anteriorly ; the latissimus dorsi and triceps posteriorly towards the dorsum of the scapula; and several muscles, such as the attenuated deltoid, the coraco-brachialis, &e., may elevate the head of the humerus, so as to bring its upper surface into contact with the acromion and coracoid process.\nWe cannot pretend to say what it is which\ndetermines the line of direction the head of the humerus in these partial displacements which occur from disease may take, or explain why the bone should in some cases take one direction, and why occasionally another ; no more than we can assign any cause for the various directions the head of the femur takes in the third stage of scrofulous caries of the hip joint, a disease we consider analogous to this we are now considering.\nAnchylosis of the shoulder joint.\u2014Anchylosis of the shoulder joint may be observed to be one of the terminations of an attack of acute or chronic arthritis of this joint. It may, we think, be remarked generally as the result of true bony anchylosis of any of the joints of an extremity, that shortening of the limb shall have taken place. This observation seems to be exemplified by what we commonly observe in studying the characters of true bony anchylosis of the shoulder joint. Most of the specimens preserved in our collection at the Richmond Hospital museum and elsewhere, present examples of solid union of the bones which compose the shoulder joint ; partial displacement upwards of the head of the humerus, and slight shortening of the extremity having previously taken place. There is at present in the museum of the Richmond Hospital a specimen of complete bony anchylosis of the shoulder joint, which was exhibited by Dr. R. Smith to the Pathological Society on the 13th March, 1841, along with some other examples of anchylosis of this joint. \u201c The specimen,\u201d observes Dr. Smith, \u201c was taken from the body of an individual aged 90, who had been confined to bed for many years Jbefore his death. The external appearance of the shoulder joint resembled somewhat those of luxation of the head of the humerus into the axilla, so far as the acromion process having been prominent, and the joint in the region of the deltoid completely flattened; the arm was rotated inwards; the glenoid cavity and head of the humerus formed one continuous bone ; the greater tubercle was anchylosed by bone to the acromion process, while the coracoid process was similarly joined to the lesser tubercle.\u201d Consequently the humerus must have been partially displaced upwards, and the arm shortened. The supra-spinatus and infra-spi-natus muscles, as well as the subscapularis, had undergone fatty degeneration from want of use ; a change very commonly observed in cases of true anchylosis of long standing, no matter which of the joints has been the seat of this termination of arthritis. In the example just adduced the humerus was observed to have ascended, and the greater and lesser tuberosities had formed a solid union with the coracoid and acromion process ; but in some examples the anchylosis has been found to have taken place directly between the surface of the glenoid cavity and the head of the humerus ; and a vertical section of the bony structures running through the consolidated joint exhibited the cells of the original head of the humerus and the diploe of the scapula","page":583},{"file":"p0584.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\n584\nfreely communicating with each other, just as we have already noticed as exemplified in complete bony anchylosis of the hip joint (see Vol. IL of this work, p. 796.). It may not be uninteresting to transfer our attention from the appearances disclosed by the postmortem examination of an anchylosis of the shoulder joint to the signs by which we recognise this state of the articulation in the living.\nA labourer, Thomas Rooney, \u00e6t. 24, appeared among the extern patients at the Richmond Hospital on Thursday, 8th June, 1848, seeking relief for some internal ailment; we noticed the wasted condition of the right shoulder joint. We learned that about three years previously he had fallen on the right shoulder and injured it ; he applied for relief to an ignorant person called a bone setter, in whose hands he suffered severely, having been subjected to violent dragging, with the view, as he was told, of reducing a supposed dislocation of his shoulder ; violent inflammation of the joint succeeded, for the treatment of which he was admitted into Sieeven\u2019s Hospital. While in the house suppuration of the joint occurred, and purulent matter made an exit beneath the anterior fold of the axilla, where the tendon of the pectoralis major is inserted into the humerus. The pain and swelling then became less, and he returned to the country, the abcess and sinus leading from it closed up, and his general health became gradually as good as it had been before he met with the accident, and remained so until he became affected with the trivial ailment he now sought advice for as an extern patient at the Richmond Hospital.\nThe shoulder joint, on a superficial examination, might be said to resemble somewhat the appearance presented in a case of an old unreduced axillary dislocation, but the resemblance was but slight. It is true that the acromion process stood out laterally, that the deltoid was flattened, that the anterior fold of the axilla was deeper than natural, and that the angular appearance the right shoulder presented was strongly contrasted with the natural rounded contour of the left shoulder joint ; but the head of the humerus could be felt underneath the acromion process ; the elbow, instead of being separated from the side as in disolcation, seemed habitually approximated to it. The biceps muscle, in consequence of the atrophied condition of the elevators of the extremities, had double duty to perform, and hence had been greatly hypertrophied at its lower part. The man can hold the plough, and can perform all the under movements of the arm very well, but cannot elevate it, nor place his forearm behind his loins.\nIn this case the arm is habitually approximated to the side, directed somewhat forwards, and strongly rotated inwards. The most striking features in the case are the wasted condition of the shoulder joint from the atrophy of the deltoid and articular tnuscles, and the extraordinary development\nof the lower part of the belly of the biceps the cause of which hypertrophy is easily understood.\nWe have seen cases in the living subject of perfect anchylosis of the shoulder joint, in which it seemed doubtful whether any shortening of the extremity existed. In these cases we must suppose that the head of the humerus became directly consolidated with the surface of the glenoid cavity, and without the more usual union having been established between the upper extremity of the bone and the superincumbent processes.\nOne of the most important points which engages the attention of the practical surgeon, in the treatment of cases of diseased joints at the period when it is expected that a process of anchylosis is going on, is to preserve the affected limb in that position which will be found most convenient to the patient, when true bony anchylosis of the joint shall have been established ; for example, under such circumstances we take care to preserve the knee and hip joints extended, the ankle and elbow joint bent to a right angle ; but the shoulder joint, when anchylosis is taking place, may be left to nature, so far as the position of the limb is concerned, because the humerus in these cases habitually remains nearly parallel to the long axis of the body, somewhat rotated inwards ; and, in a word, in a position which will be found most favourable to the performance of those functions it shall be called upon to execute when the scapulo-humeral joint is in an anchylosed state.\nChronic rheumatic arthritis of the shoulder joint.\u2014The shoulder joint is sometimes the seat of this peculiar disease, though by no means so frequently as many of the other articulations. The origin of it we have known to be attributed to accident, such as a fall on the shoulder, or to a sprain of the joint. On some occasions the sudden exposure of the person, when overheated, to currents of cold air, has been referred to as its cause ; and in others the chronic disease of the shoulder joint has been supposed to have originated in the lingering remains of a rheu-r matic fever. These are, indeed, the ordinary exciting causes of this disease in general, no matter in what particular joint it may show itself.\nSymptoms. \u2014 The patient complains of feeling pains in the shoulder joint, which, like those of rheumatism, are variable, and seem to be under the influence of changes in the atmosphere. He states that he feels a stiffness in the joint, and is conscious of a \u201ccrackling\u201d sensation in it, particularly when he first moves it in the morning. The muscles around the articulation fall into a state of atrophy, while the bony prominences around the joint generally become conspicuous from their enlargement.\nIf only one shoulder joint be affected with the ordinary form of the disease, and we compare it with that of the opposite side, the head of the humerus of the affected side will","page":584},{"file":"p0585.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 585\nbe observed to be somewhat elevated, advanced, and very generally approximated towards the middle line. When we view the articulation in profile (as it were), the amount of the advancement of the head of the hume-\nus is more readily appreciated. And when we look at the shoulder joint from behind, a very remarkable abnormal depression may be seen, which corresponds to the space or interval which exists between the posterior part of the glenoid cavity and the head of the humerus. . After a time, the voluntary motions of the joint become restricted within very narrow limits. The patient cannot well abduct the elbow from his side, nor elevate it nearly to an horizontal level. The motions he is himself capable of communicating to his arm are chiefly confined to under movements, yet the head of the humerus is in some of these cases susceptible of an abnormal degree of mobility. Although in the ordinary form of this disease the head of the humerus will be found to be placed above its normal level, and is observed to be several lines higher than the coracoid process, still if the arm be grasped by the surgeon it can be drawn down, and the head of the bone will place itself beneath the coracoid process ; the joint will then assume all the appearances usually assigned as the marks of the case styled by Sir A. Cooper \u201c Partial luxation of the head of the humerus forwards and inwards.\u201d In cases of long standing, the capsular ligament becomes wider than natural, and the articular surfaces are so altered that partial dislocation of the head of the humerus occurs in other directions besides those above alluded to ; but any observations we have to offer upon this part of our subject it will be more convenient to defer until we come to speak of the anatomical characters of this disease.\nAlthough the patient may complain of pain in the middle of the arm, and of spasms of the muscles, of the whole extremity of the affected side, even to the fingers, yet if the surgeon elevate the arm at the elbow, and press the humerus even rudely against the glenoid cavity of the affected articulation, the patient experiences no uneasiness.\nIt is very remarkable that this peculiar affection of the shoulder joint has never, as far as we have known, terminated in anchylosis, nor proceeded to suppuration ; nor has its presence excited any sympathetic disturbance in the constitution of the patient ; yet from year to year the disease slowly but gradually increases, until the patient is carried off by some other complaint, or dies from the mere effect of age alone.\nDiagnosis.\u2014This peculiar affection of the shoulder joint, particularly when the history of the case is known, cannot well be confounded with any other disease of the articulation with which we are acquainted. Scrofulous caries of the bones of the shoulder joint may have some symptoms in common with the chronic disease we are describing, but there is more pain and more wasting of the muscles of the arm and fore-arm, and\nmore sympathetic disturbance of the constitution in the case of articular caries of the shoulder than in that of' chronic rheumatic arthritis of this articulation ; and while the former case usually proceeds to suppuration, or to anchylosis of the joint, these processes never take place in the latter.\nIn the chronic rheumatic disease, the opposite shoulder joint will, in general, be found symmetrically affected ; a circumstance we have never yet known to have been the case in a chronic arthritis, or articular caries, of the shoulder.\nThe history of the case of chronic rheumatic arthritis usually betrays its nature by the general rheumatic pains the patient reports himself to have suffered from ; by the disease not being confined to the one articulation ; by the enlargement of the bony prominences about the joint, although the muscles are wasted. In both cases there may be crepitus felt on moving the joint and on making pressure ; but the efforts to elicit crepitus, and the pressing together of the articular surfaces cause, in the case of chronic arthritis, or articular caries, so much pain, that the patient shrinks back from our attempts at making these trials ; while in the ordinary case of chronic rheumatic arthritis of the shoulder, when even it appears as a local disease confined to one or two articulations, we find we can even rudely press the head of the humerus against the surface of the glenoid cavity without causing the patient pain, just as we can, in the case of the same disease when it affects the hip joint, press the head of the femur against the acetabulum without causing the least uneasiness to the patient (see Vol. II. p. 799.).\nNo doubt some few cases of chronic rheumatic arthritis of the shoulder joint in the living and in the dead have been mistaken for partial dislocation of the head of the humerus, the result of accident ; but we are of opinion that, as the chronic rheumatic affection is daily becoming better known to the profession than formerly, such errors will no longer be committed, particularly when the anatomical characters of this disease have been more fully studied by the profession.\nAnatomical characters. \u2014 When we anatomically examine the shoulder joint of a patient who has long laboured under this chronic disease in the articulation, we notice on removing the integuments that the deltoid muscle is unusually pale, and that the interstices between its fibres are occupied by an unhealthy-looking fat. This and the subjacent capsular muscles are in a state of atrophy. The capsular ligament is generally altered in form and structure, and it will be sometimes found to have abnormal attachments above to the acromion or coracoid process ; and, below, its attachment to the anatomical neck of the humerus is sometimes partially interrupted, allowing of an interval which in some forms of the disease permits the head of the humerus to pass through it.","page":585},{"file":"p0586.txt","language":"en","ocr_en":"586\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nThe capsular ligament is occasionally increased in thickness, and its fibres are hypertrophied ; and it is generally more capacious than natural, showing that effusion of synovia to a considerable amount had existed, although the external signs of this phenomenon are not usually evident. When the interior of the synovial sac is examined, it will be found to present evidences of having been the seat of chronic inflammation. Bunches of long organised fringes hang into the interior of the synovial sac; and many of these vascular fimbriae, which in the recent state are of an extremely red colour, surround the corona of the head of the humerus. We also notice rounded cartilaginous productions, appended by means of membranous threads attached to the interior of the various structures which compose the joint. Some of these foreign bodies are small, others large. Some are round ; but their shapes are various. Besides these rounded cartilaginous bodies, we occasionally find osseous productions of a multangular form added to the edges of the glenoid cavity, deepening it, and increasing the articular surface for the reception of the head of the humerus, which usually is in such cases much enlarged.\nThe intra-articular part of the long tendon of the biceps is very seldom to be seen in the interior of the joint ; but immediately outside of the capsular ligament the latter tendon will generally be found to have contracted a firm adhesion to the superior extremity of the bicipital groove {fig- 428. a.).\nBones.\u2014The head of the humerus assumes a very characteristic appearance as a consequence of this peculiar disease, and acquires a form which cannot be easily mistaken for the effects of any other disease or accident. The usual angle at which the head and neck of the humerus join the shaft of the bone is often altogether effaced ; so that instead of the axis of the head and neck of the humerus being directed, as it normally is, upwards, inwards, and backwards, it seems to run vertically, or, as it were, in a continuous line with that of the shaft of the bone. The articular surface is usually much enlarged, and in the ordinary form of this disease occupies the whole summit of the humerus, extending itself even over the greater and lesser tuberosities and the highest part of the bicipital groove ; effacing in this direction part of the circular line which marks the anatomical neck of the humerus and insertion of the capsular ligaments. Some of the articular cartilage is removed from the head of the bone, which, in some places, presents a porous appearance {fig. 428.).\nIn other parts, in place of the cartilage, there is a polished ivory-like surface. The portion of the bone which thus presents this polished surface is the very summit of the humerus ; and this is the part of the bone which will be found evidently to have been for years in habitual contact with the under surface of the acromion and coracoid process, where these bones assist in forming por-\ntions of the new and abnormal cavity for the reception of the head of the humerus. The\nFig. 428.\nChronic rheumatic arthritis : a, tendon of the biceps\nbasis of the head, in the line where it joins the shaft of the humerus, is studded round by granular osseous productions, which give to it a characteristic appearance (fig. 428.). By these vegetations of bone, we are reminded of the analogous appearance which the corona of the head of the femur presents when affected by the same species of morbid action *; but of course much variety may be expected to be found in the form the head of the humerus will assume under the influence of this disease : we have found the articular surface in some cases formed completely on the summit of the humerus, sometimes on the side of the head. Very generally the head of this bone is much enlarged, but exceptions to this rule occur. One of the most remarkable alterations of form we have noticed as the result (as we imagine) of this disease we found in the anatomical museum at Leyden. In the specimen to which we allude, the head of the humerus appears bifurcated at its upper part, or divided longitudinally into two surfaces for articulation with the scapula.'}'\nLastly, we have to advert to the anatomical characters of the new and abnormal socket formed for the reception of the altered head of the humerus. This new cavity is composed of two portions, which however will be found to have become almost continuous with each other. The original glenoid cavity (generally much enlarged) forms one of these portions ; the coraco-acromial vault the other.\n* Vol. II. fig. 317. page 802.\nf Sandifort in his fourth volume has given a delineation of the head of the humerus in this case as well as of the scapula the glenoid cavity of which was enlarged very much in the direction downwards, and was sui-rounded with a margin of osseous granules.","page":586},{"file":"p0587.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nBy the coraco-acromial vault we mean a concave surface, looking downwards, formed internally by the coracoid process, and externally by the acromion ; the intervening space being filled up in front by the proper triangular ligament of the scapula, and completed behind by a portion of the under-surface of the acromial end of the clavicle This coraco-acromial arch in the normal state overhangs much the head of the humerus, and its inferior surface is not articular, but, on the contrary, is separated from the head of the humerus, which is beneath it, by an interval of about three or four lines, measured in vertical height. This interval is normally occupied by the long tendon of the biceps and the capsular ligament, as they pass from the upper margin of the glenoid cavity to the humerus \u2014the capsular ligament having above it the tendon of the supra-spinatus, a special bursa mucosa, much cellular tissue, and the fibrous bands, which pass from the humerus to the coracoid and acromial processes.\nUnder the influence of the most usual form of this disease, all these parts intervening between the head of the humerus and the coraco-acromial arch or vault are absorbed ; and the superior extremity of the head of the humerus at length comes into immediate contact with the concavity of the arch. The first effect of this morbid process in bringing about the remarkable changes which we have been describing, may be to cause the absorption of those tendons, viz. the supra-spinatus and the long tendon of the biceps, which pass over the head of the humerus, and which, by virtue of their muscular attachments, restrain within proper limits the degree of elevation * which the head of the humerus is normally susceptible of. When, however, these tendons are absorbed, and consequently the muscles to which they belong have lost all power of repressing the humerus, the latter is then dragged upwards, and its head being constantly pressed against the under-surface or concavity of the coraco-acromial arch, not only do the processes of the scapula which form this arch at length show manifestly the effects of friction, but the outer portion of the acromial end of the clavicle does so equally. All these portions of bone are rendered concave, and are usually covered by a porcelainlike deposit, corresponding to an analogous polished surface which covers the convexity of the summit of the humerus. In many cases in which the shoulder joint has long been the seat of this chronic disease, the acromion process has been found traversed in the line of junction of its epiphysis, by a complete interruption of its continuity, as if fractured : we say as if fractured, for we are convinced that this solution of continuity of the acromion process is not really a fracture produced by violence, but a lesion, which so frequently exists in combination with chronic rheumatic\n* If the long tendon of the biceps be dislocated and thrown inwards over the head of the humerus, the same effects will be produced as if it were ah-sorbedi\narthritis of the shoulder, that we are compelled to look upon it, in these cases, as a peculiar organic change, the result of chronic rheumatic disease. We do not pretend to account for the separation of the acromion process into two portions ; nor can we say why it is that the division usually occurs in the original line of the epiphysis, particularly at the late period of life at which we generally witness this phenomenon. In some of these cases we have found the acromion in a state of hypertrophy ; in others in a state of atrophy ; but in no case did there seem to be any attempt at ossifie deposition on the contiguous surface of the separated portions of the acromion, a circumstance which might be expected if a fracture had occurred.\nThe glenoid cavity of the scapula, under the influence of this disease, is generally much enlarged ; and by becoming wider above, it loses much of its ordinary ovoidal figure, approaching in its outline more to a circular form. The surface of the cavity appears preternatu-rally excavated, its brim being elevated into a sharp margin. The cartilage of incrustation, as well as the glenoid ligament, are generally removed altogether, some parts of the surface are porous, and some covered with porcelainlike enamel. Near the margins of the glenoid cavity, where the capsular ligament arises, we may often find osseous productions attached to the capsular ligament, adding depth to the receptacle for the enlarged head of the humerus. The glenoid cavity will of course be found to present much variety of form. Sometimes the head of the humerus occupies its upper portion, and habitually remains in contact with the under surface of the acromion and coracoid process, thus leaving the lower part of the glenoid cavity unoccupied.\nSometimes part of the head of the humerus remains within the glenoid cavity, while the remaining portion of it occupies the neighbouring part of the subscapular fossa. Occasionally the head of the humerus will be found to have descended on the axillary margin of the scapula*; while in other cases equally rare, which we shall hereafter have occasion to refer to, the head of this bone may, under the influence of this disease, pass backwards on the dorsum of the scapula: under all these circumstances, the glenoid cavity must undergo special changes of form adapted to each variety.\nThose who carefully study the anatomical characters of chronic rheumatic arthritis of the shoulder, cannot fail in the course of their investigation to observe many deviations from the normal state of the joint, the result of this disease, which are well calculated to mislead those who are unacquainted with it ; to which we may here advantageously advert.\nIt has been repeatedly remarked, that one of the most constant anatomical observations we had to make in post-mortem examinations of the shoulder joints of those who had been\n* Catalogue of the Museum of the College of Surgeons, Dublin, vol. i. p. 399. Prepar. E. b. 905.","page":587},{"file":"p0588.txt","language":"en","ocr_en":"588\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\naffected with chronic rheumatic arthritis was, that the long intra-articular portion of the tendon of the biceps was absent from the joint, although adherent outside to the highest point of the bicipital groove (^g.428.). Thisremoval of a large portion of the tendon of the biceps strikes the observer who is unacquainted with this disease as a direct proof that the tendon had been ruptured by accidental violence, and that a partial luxation of the head of the humerus has been the consequence.\nAnother character of this disease is, that the humerus has a very general tendency to pass upwards towards the coraco-acromial vault ; and besides the removal of the tendon of the biceps, the superior part of the capsular ligament is observed to be deficient. Those who do not know that this perforation is a consequence of slow disease, immediately take it for granted that the same accident which ruptured the tendon of the biceps had also caused the head of the humerus to be partially dislocated upwards, perforating as it passed the superior part of the capsular ligament.\nIf, in addition to these abnormal appearances, small portions of bone, as if fragments broken off from the margins of the glenoid cavity, are found to be present, as they frequently are, this also is an appearance calculated to confirm an erroneous impression, that some external violence has been the source of it ; and if in addition the acromion process be found divided into two portions, as we have frequently noticed it, the prejudice in the observer\u2019s mind may at first be strongly in favour of the idea,'that accidental violence has been the source of these many and combined phenomena.\nBut notwithstanding all these lesions, namely, the total disappearance of the articular part of the tendon of the biceps ; the perforation of the superior part of the capsular ligament by the head of the humerus, and the separation into two portions of the acromion process, we feel convinced that all these phenomena combined should by no means be considered as proof of any accident having occurred to produce them ; but, on the contrary, should be looked upon as the usual result of chronic rheumatic arthritis of the shoulder.\nThe tendon of the biceps in all those cases of presumed accidents is said to be ruptured; yet the chronic disease of the shoulder joint is frequently found to affect both shoulder joints in the same individual, and the long tendon of the biceps, in these cases, to be removed on both sides. It is easy to conceive that this double lesion may be the effect of disease, but difficult to imagine how any accidents could occur to \u201crupture\u201d the tendons of the biceps in both shoulder joints. Nor is it easy to admit that the long tendon of the biceps can be readily ruptured in partial dislocations of the humerus from accident, when we know that this tendon is rarely if ever ruptured, even in complete luxation of this bone. The statement made in the report of various cases\nin surgical works, and in the catalogues of museums, in which we find it briefly noted, \u201c that the tendon of the biceps was found ruptured,\u201d has been made by the writers confessedly without any knowledge of the previous history of the case, the anatomical characters of which they are describing. On this account we feel the less delicacy, after long and patient consideration of the subject, in expressing our conviction that the tendon of the biceps, in the numerous cases published, was not (as supposed to be) ruptured by accident, but absorbed as the result of disease.\nWe have stated that the bones entering into the formation of the shoulder joints are very generally enlarged as a consequence of this chronic disease having for a considerable time existed in the articulation. It is right, however, here to observe, that very extensive inquiry into the pathological anatomy of this peculiar affection as it presents itself in the shoulder joint, will prove that some few exceptions to this rule may be occasionally met with ; and that, instead of the bones entering into the formation of the shoulder joint being found hypertrophied, they may be discovered, on the contrary, to be in a state of atrophy ; or portions of these bones may be removed altogether, as the apparent result of this chronic rheumatic disease.\nThat the writer may not appear to have been singular in having observ\u00e9d the changes which the acromion process and neighbouring bones have undergone as the result of this chronic rheumatic disease, he may refer to the dissection of a case mentioned by Cruveilhier, in which the affection we have called chronic rheumatic arthritis was so general that there was scarcely any articulation in the body exempted from its effects. When adverting to the anatomical changes observable in the region of the shoulder in this example, he says, the external extremity of the clavicle and the neighbouring part of the acromion were in a great part destroyed, &c.*\nIn the museum of the College of Surgeons in Dublin will be found a preparation of a shoulder joint, which is styled by the late Dr. Houston in his catalogue, a specimen of chronic rheumatic arthritis of the shoulder ; and that it was justly so styled may also be inferred from the \u201c bunches of synovial fimbriae,\u201d which hung into the synovial cavity of the joint ; the existence of hydrops ar-ticuli, or over-distension of the synovial sac by an albuminous fluid ; and from the deficiency of the intra-articular portion of the tendon of the biceps, mentioned in the account given of this case : \u2014 all these show the disease to have been correctly designated. The writer finds upon examining this preparation with the intelligent curator, Mr. Carte, that the acromial end of the clavicle is unsupported, and that the acromion process has been removed for the amount of an inch in extent; that which remains for this process\n* Cruveilhier, livraison ix. p. 12.","page":588},{"file":"p0589.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nis thinner than natural, and in a state of atrophy.*\nThe coracoid process is not usually found so much altered by the existence of this peculiar disease in the shoulder joint as the acromion; but we have found its under concave surface in some cases to have entered into the formation of the shoulder joint, and to have presented a broad glenoid-shaped surface, which had been smoothed oft\u2019 from frequent contact with the head of the humerus, while the breadth of the process had been at the same time much increased.\nWe have thought it necessary to enter into this subject thus minutely, because we are convinced that, up to the present hour, these remarkable appearances, when met with, have been misunderstood even by some of the most intelligent anatomists and physicians. This circumstance may appear perhaps capable of explanation, by recollecting that the disease generally runs a long course, is not in itself fatal ; and hence, although the practical medical man may have had numerous opportunities of witnessing the symptoms of this disease in the living, he may never have had any opportunity in any case of informing himself of the true relation subsisting between the symptoms of this disease of the shoulder joint as observed in the living patient, and the phenomena which the post-mortem examination of the same shoulder joint might have presented. On the other hand, when anatomists have heretofore discovered in dissection appearances which are stated to be truly those of chronic rheumatic arthritis of the shoulder, they have not at that time been able to learn the previous history of the case.\nThe following case may contribute somewhat to supply this deficiency :\u2014\nCase. Chronic rheumatic arthritis of the shoulder. \u2014 J. Byrne, a servant, \u00e6t. 55, was admitted into the Whitworth Hospital House of Industry in 1834. Dr. Mayne, at that time resident clinical clerk in the hospital, informed the writer that, besides the disease of the lungs, for which the man was admitted, he also had an affection of the right shoulder joint, which presented all the characters attributed to the case of partial luxation of the humerus, and was kind enough to invite the writer to examine him.\nThe man complained of an inability to use his right arm well, in consequence of his having for some years an affection of his right shoulder joint, in which he felt almost continually a dull boring pain. He could however perform, without much inconvenience, all those motions of the arm which did not require it to be raised near to the horizontal line. The joint felt to his own sensation somewhat stiff ; and he was conscious, under certain movements of the arm, of a sense of something crepitating or crackling in the joint. Upon viewing the shoulder in front, it had a\n* See a preparation in the Museum of the College of Surgeons, Dublin, Catalogue, vol. ii. p. 397. E. 6. 901.\tv\nwasted appearance ; the acromion process was more prominent, rendering the bony eminences around very conspicuous ; the head of the humerus seemed to be a little higher than usual, and to have advanced somewhat forwards. The amount of advance was best seen by viewing the joint in profile or laterally. In this aspect a slight elevation and the increase of the antero-posterior measurement of the joint became very obvious. When the arm was pressed by the surgeon, and very slight force used, the humerus could be easily made to descend somewhat, and at the same time to pass a little beneath the outer margin of the coracoid process ; and the finger could be readily pressed into the outer half of the glenoid cavity, into the space which the head of the humerus was found to have abandoned. When again the shaft of the humerus was elevated vertically, its superior extremity could be felt to strike against the under surface of the acromion. In a word, the symptoms strongly resembled those usually assigned to the partial luxation forwards and inwards.\nThis patient remained in the Whitworth Hospital until the pulmonary affection proved fatal. Dr. Mayne and the writer carefully examined the joint, which is still preserved in the museum of the Richmond School (fig- 429.).\nWe found the deltoid and other muscles around the joint in a wasted condition, and much paler than those of the opposite shoulder. When the capsular ligament was exposed, it was found to have superiorly a much wider and more extensive adhesion than natural. Instead of this fibro-synovial sac having its ordinary attachment all round to the limited circumference of the glenoid cavity of the scapula, its adhesion to the upper margin of this cavity did not exist, but the superior and outer portions of the capsular ligaments seemed to have acquired new attachments, and to be connected superiorly and externally with the anterior margin of the coraco-acromial arch ; and thus the space in which the head of the humerus had been permitted to move, had been rendered much more extensive than natural.\nThe capsular ligament was much thickened, and when opened more synovia than usual flowed out. This membrane was lined with cellular floeculi, and several small cartilaginous bodies, rounded, and of the size of ordinary peas, were seen to float in the interior of the synovial sac, appended by means of fine membranous threads. All those parts which, in the normal condition, intervene between the superior part of the head of the humerus and under surface of the coraco-acromial arch, were completely removed. No remnant or trace of the supra-spinatus tendon, nor any portion of the capsular ligament to which this tendon is attached, was to be found. The entire of the articular portion of the tendon of the biceps was absent, and the highest point of the remaining portion of the tendon was attached to the summit of the","page":589},{"file":"p0590.txt","language":"en","ocr_en":"590\nABNORMAL CONDITIONS\nbicipital groove. It was remarkable that the acromion process and other portions of bone,\n* Fig. 429.\nCase of J. Byrne. \u2014 Chronic rheumatic arthritis.\na, line of complete division of the acromion into two portions ; b, coracoid process ; c, acromial end of the clavicle, worn by the attrition of the head of the humerus ; d, tendon of the biceps adherent to the bone ; e, glenoid cavity ; f, capsule widened ; foreign bodies attached to it.\nviz. the outer extremity of the clavicle and I coracoid process, had acquired size and density,\n; although their under surfaces were much worn and excavated where they formed an arch which overhung the humerus. These appearances showed the great degree of friction and pressure from below upwards which these bones had been subjected to, from the head of the humerus being constantly drawn upwards by muscular action. We also noticed that the acromion process was traversed from within outwards by a perfect solution of continuity, completely dividing it into two nearly equal portions. This might be supposed by some to have been a fracture which never had been united by bone \u2014 an opinion which, however, we did not entertain ; the two pieces of the acromion were on a perfect and uniform level, and the edges of the separated portions of bone exhibited no evidence of any ossifie deposit, nor any such appearances as would lead us to infer that a fracture had existed.\nThe glenoid cavity of the scapula was larger and deeper, and more of a cup-like form than usual. The cartilage of encrustation and glenoid ligament were removed, the surface of the cavity presented a porous appearance. Along its inner margin were arranged several round and firm cartilaginous granules.\nThe head of the humerus was somewhat\nOF THE SHOULDER JOINT.\nenlarged. The articular surface had become extended over the superior margin of the greater and lesser tuberosity. Much of the cartilaginous investment of the head of the bone had been removed, and its place supplied by means of a porcelain-like deposit. The line which marks the junction of the head of the bone to the shaft, was studded all round with granular elevations of bone (fig. 429.).\nOur knowledge of the anatomical characters of this disease has now arrived at a degree of precision quite sufficient, we might suppose, to save us henceforth from falling into the error of confounding the morbid results of chronic rheumatic arthritis of the shoulder with the consequences of chronic or acute osteitis, or with the ultimate effects of accidents sustained during the patient\u2019s lifetime. Nevertheless we feel called upon now to allude to some cases of partial luxation of the shoulder joint which have been published as the result of accident, but which we consider to be specimens of the chronic rheumatic disease of the shoulder joint which we are endeavouring to describe.\nAmong these authors we find Sir A. Cooper, who, in his description of the accident called by him \u201c partial luxation of the shoulder joint, forwards and inwards, to the coracoid process,\u201d gives a case which he supposed to be one of this accident, and relates the symptoms to teach us how it may be recognised ; but for its anatomical characters he refers to an example found in the dissecting room, the history of which was unknown. He says, \u201c The only dissection of this accident which I have had an opportunity of seeing was the following, for which I am indebted to Mr. Patey, surgeon in Dorset Street, who had the subject brought to him for dissection at the anatomical room, St.Thomas\u2019s Hospital. The following is Mr. Patey\u2019s account : \u2014\n\u201c * Partial dislocation of the head of the os humerus.\u2014 The head of the os humeri on the left side was placed more forward than is natural, and the arm could be drawn no farther from the side than the half way to an horizontal position.\n\u201c \u2018 Dissection.\u2014The tendons of those muscles which are connected with the joint were not torn, and the capsular ligament was found attached to the coracoid process of the scapula. When the ligament was opened it was found that the head of the os humeri was situated under the coracoid process, which formed the upper part of the new glenoid cavity; the head of the bone appeared to be thrown on the anterior part of the neck of the scapula, which was hollowed, and formed the lower portion of the glenoid cavity. The natural rounded form of the head of the bone was much altered, it having become irregularly oviform, with its long axis from above downwards : a small portion of the original glenoid cavity remained, but this was rendered irregular on its surface by the deposition of cartilage. There were also many particles of cartilaginous matter upon the head of the os humeri, and upon the hollow of the new","page":590},{"file":"p0591.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\ncavity in the cervix scapul\u00e6, which received the head of the bone. At the upper and back part of the joint there was a large piece of the cartilage luhich hung loosely into the cavity, being connected with the synovial membrane at the upper part only by two or three small membranous bands. The long head of the biceps muscle seemed to have been ruptured near to its origin at the upper part of the glenoid cavity, for at this part the tendon was very small, and had the appearance of being a new formation.\u2019 \u2014 Signed, James Patey.\n\u201c This accident,\u201d adds Sir Astley, \u201c happens from the same cause which produced the dislocation forward. The anterior part of the ligament is torn, and the head of the bone has an opportunity of escaping forwards to the coracoid process.\u201d *\nThe foregoing dissection, which is illustrated by an engraving in Sir A. Cooper\u2019s work on Fractures and Dislocations, should not, in our opinion, be considered in any other light than as an excellent specimen of the anatomical appearances to be found in those who have had chronic rheumatic arthritis of the shoulder joint ; for we consider that these appearances were not the result of an accidental luxation, but the true effects of this slow chronic disease. If Sir A. Cooper had known any thing of the history of the case during life, we might hesitate to call in question the opinion of so eminent an authority on such a subject ; but as the only grounds he possessed for forming any opinion were derived from the mere anatomical appearances observed in the shoulder joint of the subject in the dissecting-room, we conceive that every one who studies the report of this dissection, accompanied as it is by an engraving, is at liberty to draw his own conclusion as to what was the real nature of the case ; and to us it seems quite clear that the appearances observed in the examination of the case referred to by Sir A. Cooper were exactly those most frequently found to be the result of chronic rheumatic arthritis as itaffects the shoulder joint. The new form assumed by the head of the humerus, the fact of the cartilage having been removed, and its place supplied by an ivory enamel\u2014the piece of cartilage which hung loosely into the cavity being connected with the synovial membrane, at the upper part only, by two or three small membranous bands\u2014the attachment of the capsular ligament to the coracoid process \u2014 all these circumstances related in the above-mentioned case strongly remind us of what we now know to be characteristic marks of the disease we have denominated chronic rheumatic arthritis, as we have so often met with them. Add to this, the observation that the intra-ar-ticular portion of the long tendon of the biceps muscle did not exist ; or, as is presumed, to have been \u201c ruptured \u201d at its origin.\n* See Sir A. Cooper on \u201cDislocations,\u201d p. 449. Plate 21. fig. 2. ; also octavo edition of this work by Mr. B. Cooper, p. 401.\nIn all these details we find a very complete account of the anatomy of the shoulder joint which had been the seat of chronic rheumatic arthritis.\nOn the other hand, such appearances afford no evidence whatever that an accidental luxation was the cause of them ; certain it is that appearances exactly resembling those described in Sir A. Cooper\u2019s case have been met with in cases in which their cause could not be attributed to accident, because no injury had been received; while in others it was useless to refer to accident, inasmuch as the morbid action had similarly affected both shoulder joints ; so that by the dissection of such cases we have convinced ourselves that disease, not accident, was the source of the morbid appearances. If the reader will compare the woodcut (fig. 429.), which is designed to represent the anatomical appearances presented by the examination of a case (J.Byrne) already detailed, of chronic rheumatic arthritis of the shoulder, with the engraving of Sir A. Cooper\u2019s case of partial luxation of the head of the humerus, he will, we think, agree with us that the writer, in believing that whatever causes influenced the production of the morbid appearances in the one were identical with those which produced them in the other. Sir A. Cooper, in our opinion, somewhat gratuitously supposes that his specimen was the much sought-for example of the anatomy of the accident called partial luxation. We say gratuitously, because the previous history of the case he alludes to was unknown, and the accident supposed to have occurred.\nIn the case the writer has adduced (J. Byrne, (fig. 429.), the history was known, and has been preserved, with the account of the post-mortem appearances which the examination of the shoulder joint presented.\nAt the meeting of the British Association at Bristol in September, 1836, the author gave an account of this chronic rheumatic disease, as it engages most of the joints. When speaking of its effects on the shoulder, he alluded to this case published by Sir A. Cooper ; and then demonstrated, as he thought, to the satisfaction of the meeting, that the specimen {fig. 429.) of this chronic rheumatic disease which he then laid before them for inspection, corresponded exactly to the appearances found in the supposed case of \u201c partial luxation of the humerus \u201d delineated in Sir A. Cooper\u2019s work. The opinion which he at that time expressed (now twelve years ago) has since been amply confirmed by his subsequent experience *, and by the opportunities he has had of further investigating the nature of this disease.\nIn the Museum Anatomicum j\" of Sandi-fort, 1827, we find delineated the bones of the shoulder joint which present all the cha-\n* See Athen\u00e6um, September 10, 1836 ; also Proceedings of tbe Dublin Pathological Society, Dublin Journal, vol. xv. p. 502.\nf Yol. iv. tab. 24. figs. 1, 2, 3.","page":591},{"file":"p0592.txt","language":"en","ocr_en":"592 ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nracters of the chronic rheumatic arthritis, with partial displacement upwards of the head of the humerus. Sandifort also, we feel sure, has fallen into the error of concluding without proof, that this specimen of the bones of the shoulder constituted an example of partial luxation from accident (\u201c luxatio ossis humeri ab injuria externa \u201d). The subject of this case, he says, was a robust man: the head of the humerus having been driven upwards between the coracoid process and the acromion, a new articular surface was produced, partly on the upper narrow part of the glenoid cavity, and partly on the root of the coracoid process. This new articular surface, in its centre porous, was as to its circumference hard, polished, and ivory-like (\u201c partim porosa sed caetera vald\u00e8 polita ac quasi eburnea\u201d), and had been in habitual contact with the head of the humerus. The latter was much enlarged, and its circumference near the corona of the head was much increased by the addition of a hard rounded margin (\u201c margine revoluto calloso\u201d). The wearing away of the upper part of the great tuberosity, the eburnisa-tion of the summit of the humerus where it came in contact with the concavity of the coraco-acromial vault, the preternatural contact of the head of the humerus with the under surface of the acromial extremity of the clavicle, are also noticed. \u201c Caput ossis humeri amplitudine auctum, margine revoluto calloso, in superficie articulari affert eandem pr\u00e6ternaturalem glabritiem et duritiem, dutn in vertici, ubi tuberculum majus occurrit, superficiem exhibet partim glaberrimam, partim inequabilem, rugosam, qu\u00e6 juxta sum-mum humerum movebatur trituratione, etiam locum habuisse inter marginem inferiorem clavicul\u00e6, et verticem capitis humeri manifeste apparet ; subluxatio in superiora ergo hie locum habuit.\u201d*\nHere we find the description of the bones unaccompanied with any account of anatomical characters of the other structures of the joints ; nor is there any proof adduced that any accident had occurred to produce the appearance noticed ; we may therefore, we think, conclude, that the history of the case was unknown. When we compare Sandifort\u2019s description of the above case, accompanied as it is with an engraving, with the account given by us in the preceding pages of the dissection of other cases of the chronic rheumatic arthritis as it affects the structures of the shoulder joint, we think we may safely conclude that this case, adduced by Sandifort as an example of partial luxation of the head of the humerus upwards from external injury, must be considered as presenting in the bones described the anatomical characters of chronic rheumatic disease, as it very commonly affects the bone of the shoulder joint.\nIn the anatomical examination of advanced cases of this disease of the shoulder joint, which we have witnessed, in which there\n* Museum Anatomicum Sandifort, tab. eli. figs: 1, 2, 3. vol. iv.\nhad been partial luxation of the head of the humerus upwards \u2014 when the deltoid muscle has been cut through, the head of the humerus has been usually found exposed, and in absolute contact with the under surface of this muscle, having passed through the upper part of the capsular ligament. In such cases, the head of the humerus has been found to present the usual characteristic appearances of this chronic rheumatic disease ; that is to say, the cartilage has been absorbed, and its place supplied by an ivory-like enamel. The articular portion of the tendon of the biceps has also been removed, as well as all those parts which in the normal state intervene between the summit of the head of the humerus and the under surface of the coraco-acromial arch. The superior portion of the capsular ligament itself has been found perforated ; and the under surface of the coraco-acromial vault excavated, and has become a new and supplementary socket for the head of the humerus {fig. 429.).\nThe explanation of the circumstance why the superior and external part of the capsular ligament has been found perforated by a large circular opening, through which the head of the humerus can pass, appears to be, that the effects of the loss of the tendon of the biceps are such, that the head of the humerus is at once elevated by the deltoid, and kept habitually pressed up against the under surface of the acromion. The coraco-acromial vault now becomes the articular socket for the head of the humerus, more than the original glenoid cavity. The head of the humerus assumes altogether a new form ; its summit is expanded, and at the same time smoothed by the constant effects of use and friction ; the anatomical neck is encroached upon, and gradually the whole summit, including the great and lesser tuberosities, becomes articular, these latter eminences being, as it were, ground down and covered with a por\u00e7elainous deposit (\u00dfg. 428.). As the upper* portion of the circular groove, called the anatomical neck of the humerus, which normally gives attachment to the capsular ligament of the joint, has been removed, this attachment of the capsule must be destroyed, and a large opening will be found in it. This occurrence is well illustrated by a case of chronic rheumatic arthritis of the shoulder joint, described b}' Mr. Hamilton Labatt, who entitles the case, \u201c An excellent specimen of that chronic disease of the shoulder joint which old people are liable to ; as also an example of partial luxation upwards, the result of slow disease.\u201d *\nThe history of this case, as of almost all of the same kind published, was unknown. The subject was a female aged 60, brought into the College of Surgeons for dissection ; the muscular system well developed. The common integuments had been removed when Mr. Labatt was called to witness the dissec-\n* Vide London Medical Gazette, 1838, vol. xxii. p. 22.; also Catalogue, Coll. Surgeons, Ireland, vol. ii. p. 396.","page":592},{"file":"p0593.txt","language":"en","ocr_en":"593\nABNORMAL CONDITIONS\ntion, and the deltoid muscle was cut across and thrown back, when the attention of the dissector was attracted by the head of the humerus, which was exposed and firmly supported against the under surface of the acromion process by the lips of a vertical rent in the capsular ligament, which was otherwise healthy, firmly girding the anatomical neck of the humerus. The articular cartilage of the head of the humerus had been universally eroded. The head of the humerus had been increased in size by the addition of an osseous margin, which overhung the anatomical neck of the humerus. Several cartilaginous bodies, connected to the surrounding fibrous tissues, projected into the cavity of the joint. The larger were pedunculated and pendulous, while the smaller were attached by broad surfaces. The articular part of the biceps tendon had disappeared. The capsular ligament was thickened ; and the longitudinal aperture already mentioned, which existed in the upper art, was sufficiently capacious to allow the ead of the bone under certain circumstances to pass with facility from its natural situation upwards, and to come in contact with the under surface of the acromion process. The coraco-acromial articulation of the same side, as well as several of the other articulations in this subject, exhibited unquestionable traces of having been affected with the same disease.*\nWhen a specimen of chronic rheumatic arthritis of the shoulder joint, such as the preceding, has been met with, by anatomists not familiar with the ordinary anatomical characters of the disease, it is usually mistaken for a case of partial displacement of the humerus upwards, the result of accident. We find many such cases and such mistakes recorded. Although the history of Mr. Labatt\u2019s ease was unknown, the appearances which the head of the humerus presented were sufficiently characteristic to clearly designate the true nature of the affection, independently of the condition alluded to of the coraco-clavicular and other articulations, so many concurring circumstances sufficiently proved that, in the above case, the shoulder had been long affected by the chronic rheumatic arthritis, and that this, and not accident, was the source of the partial luxation upwards which existed.\nIn April, 1840, Dr. Robert Smith, who is well acquainted with this disease, laid before the Surgical Society of Dublin an account of the post-mortem examination he had made of an aged female, who died of an internal organic disease in the House of Industry. She had been long affected with a partial displacement upwards of the right humerus, which was the result of chronic rheumatic disease. He presented a cast of the upper part of the body, taken after death, showing the degree of elevation of the summit of the humerus on the - affected side; and also exhibited a prepara-\n* This specimen is preserved in the Museum of the College of Surgeons. Vide Catalogue, Coll. Surg. Ireland, vol. ii. p. 396.\nVOL. IV.\nOF THE SHOULDER JOINT.\ntion of the shoulder joint to the meeting. The post-mortem examination had been made a few weeks previously to Dr. Smith\u2019s communication of this case to the society. \u201c It may be seen,\u201d he said, \u201c from the cast, that in this case there was a remarkable contrast in the appearance the two shoulder joints presented : on one side, the head of the humerus was placed far above the level of the coracoid and acromion processes. Many persons,\u201d he added, \u201c in viewing the cast and accompanying preparation, might consider the specimen as one of some unusual form of congenital malformation, or the result of accident ; but the abnormal appearances were clearly the result of that peculiar affection of the joints, of which so many specimens had been elsewhere brought forward by the president in the chair (Mr. Adams), and which disease he has denominated \u2018 chronic rheumatic arthritis.\u2019\u201d Dr. Smith added that his chief reason in bringing forward the case was, that it presented some peculiarities he had not observed in other specimens of the same disease, as it affects the shoulder joint : he had often before noticed the elevation of the head of the bone as a symptom of this affection, but had never seen the elevation to the same degree it had amounted to in this case. The head of the humerus was displaced upwards, even to a point above the level of the clavicle and acromion process. The capsular ligament was enlarged, and as thin as if the synovial membrane alone constituted it. Superiorly, this capsule was altogether deficient : a large aperture was here found, which permitted the head of the humerus to pass upwards, as already mentioned ; the tendon of the biceps was perfect, but was thrown off the head of the bone inwards. The cartilage of the head of the bone was abraded in several places, and osseous depositions had been formed in the vicinity of the bicipital groove, and around the margin of the articular head of the humerus, as is usually the case in examples of chronic rheumatic disease. Mr. Smith observed, that the preparation showed a large deficiency in the upper part of the capsular ligament \u2014 a fact not before observed by him, until he had seen Mr. Labatt\u2019s preparation; and even then he was disposed to attribute the deficiency to some injury received in removing the parts. He had therefore taken the greatest care in removing the preparation just exhibited to the society, and had found that in dividing the deltoid muscle he had cut at once into the cavity of the joint.\nDr. Smith and the writer have lately carefully examined this preparation, and find that the acromion process has been much reduced in thickness ; its under surface is excavated, and denuded of all periosteal covering ; this process is divided into two portions, as if a fracture had traversed the original line of the junction of the epiphysis with the rest of the process : half an inch in extent of the bone is thus separated from the rest, and seems merely retained by a ligamentous connection.\nThe deltoid and triangular ligament were\nQ Q.","page":593},{"file":"p0594.txt","language":"en","ocr_en":"594\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nrelaxed :\u2014\u201c The shoulder joint presented a remarkable degree of mobility in this case ; and the head of the humerus of the affected side could be pushed half an inch higher than its fellow.\u201d The great peculiarity in this case Dr. R. Smith thought consisted in the circumstance that the tendon of the biceps was not, as it usually is in cases of this chronic disease, absorbed, but was in a perfect state of integrity as to structure.\nThis tendon having been thrown off the head of the humerus, and displaced inwardly, its normal function to restrain the ascent of the humerus, through the medium of its muscular connection, was as much annulled as if it had been removed altogether, as it usually is, under the influences of this chronic disease.\nQuestions here naturally arise : Can the tendon of the biceps be dislocated from its groove by accidental violence ? and if so, Shall the consequent dislocation of the head of the humerus be in the direction upwards, exactly as it was in the preceding case, which was evidently an example of the displacement of the tendon from disease.\nMr. John Soden, junior, of Bath, has published a case, accompanied by some interesting remarks, the objects of which are to prove that the tendon of the biceps may be dislocated by accident, and that a partial displacement of the head of the humerus upwards must immediately follow.\nMr. John So den\u2019s case.\u2014Partial dislocation upwards. \u2014 \u201c Joseph Cooper, aged 59, was admitted into the Bath United Hospital, November 9, 1839, on account of a compound fracture of the skull. His death afforded an opportunity of examining an old injury of the right shoulder, the symptoms of which had been always involved in great obscurity, and which occurred in the following manner : \u2014\n\u201c In the month of May, 1839, the deceased (six months before his death) was engaged in nailing down a carpet, when, on rising suddenly from his occupation, his foot slipped, and he fell backwards on the floor. In order to break the force of the fall, he involuntarily placed his arm behind him, and by so doing received the whole weight of the body upon his right elbow ; that joint, the oniy one struck, received no injury, for the shock was instantly transmitted to the shoulder, and there the whole effects of the accident were sustained. Acute pain was immediately experienced, and the man supposed he had either suffered a fracture or a dislocation, but finding that he could raise the arm over his head, he felt reassured, and endeavoured to resume his work. The pain, however, compelled him to desist, and he went home.\u201d \u201c When I saw him,\u201d says Mr. Soden, \u201c on the following morning, the joint was greatly swollen, tender to the touch, and painful on very slight motion. There was then no possibility of his placing his arm over his head, as he had done immediately after the accident. I satisfied myself that there was nei-\nther fracture nor dislocation of the bones, and not suspecting the existence of a more specific injury than a severe sprain, I set down the case as such, and avoided the unnecessary pain of further examination. Unusually active means were necessary to subdue the inflammation, and at the end of three weeks, though the swelling was much reduced, the tenderness in the front of the joint, and pain on certain motions of the limb, were scarcely less than on the day after the occurrence of the accident.\n\u201c On comparing the joint with its fellow, now that the swelling had subsided, a marked difference was observable between their respective outlines. The injured shoulder was evidently out of drawing, but without presenting any glaring deformity : when the man stood erect with his arms dependent, the distinction was very manifest, but difficult to define. There was a slight flattening on the outer and posterior part of the joint, and the head of the bone looked as it were drawn up higher in the glenoid cavity than it should be. Examination verified the appearance in two ways : first, on moving the limb, with one hand placed on the shoulder, a crepitating sensation was experienced under the fingers, simulating a fracture, but in reality caused by the friction of the head of the humerus against the under surface of the acromion : secondly, on attempting abduction, it was found that the arm could not be raised beyond a very acute angle with the body, from the upper edge of the greater tubercle coming in contact with that of the acromion, and thus forming an obstacle to all further progress. The head of the bone was also unduly prominent in front, almost to the amount of a partial dislocation. For all useful purposes the arm w>as powerless. The pain caused by the action of the biceps was acute, extending through the whole course of the muscle, but felt chiefly at its extremities. When the joint was at rest the pain was referred to the space in front, between the coracoid process and head of the humerus ; which spot was marked by extreme tenderness and some puffy swelling.\n\u201c The patient being of a rheumatic habit, inflammatory action of that character was soon established in the joint, so that the peculiar symptoms of the injury were marked by those of general articular inflammation, which added greatly to the man\u2019s suffering, and to the difficulty of diagnosis. On examining the joint the accident was found to have been a dislocation of the long head of the biceps from its groove, unaccompanied by any other injury. The tendon was entire, and lay enclosed in its sheath, on the lesser tubercle of the humerus ; the capsule was but slightly ruptured ; the joint exhibited extensive traces of inflammation ; the synovial membrane was vascular and coated with lymph ; recent adhesions were stretched between different parts of its surface, and ulceration had commenced on the cartilage covering the humerus, where it came in contact with the under surface of the acromion ; the capsule was thickened and ad-","page":594},{"file":"p0595.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t595\nherent, and in time, probably, anchylosis might have taken place.\u201d\nObservations on this case. \u2014 In this interesting case, recorded by Mr. Soden, it is true that the tendon of the biceps was dislocated; but, we may ask, are the appearances noticed during life, as well as the condition of the shoulder joint found on examination after death, capable of any other explanation than that given to them by Mr. Soden? Upon such a matter we feel we ought to speak with the greatest diffidence, because this case is so far unlike almost every case of partial luxation yet published in this circumstance, that its history was known before the post-mortem examination of the joint was instituted. However, we must confess that we do not as yet feel convinced that the case of partial displacement upwards of the head of the humerus, as the immediate and direct result of accident, has been fully proved by Mr. Soden. If we analyse the symptoms the patient himself reports to have observed immediately after the accident, we find that he at first supposed he had either suffered a fracture or a dislocation, but finding that \u201c he could raise the arm over his head\u201d he felt re-assured, and endeavoured to resume his work. It would appear to us, that if the tendon of the biceps were accidentally dislocated the patient would not be able, immedi tely after the accident, to raise his arm over his head ; while the circumstance here noticed seems quite reconcilable with Mr. Soden\u2019s own impression, that there was in this instance no other injury than a severe sprain of the joint. The symptoms under which the patient subsequently laboured were those of an inflammatory character, such as might have been expected where so severe a sprain had occurred, as we may suppose the shoulder joint in this instance to have suffered. The appearance the joint presented externally when the disease became subacute, or chronic, namely the flattening of the outer and posterior part of the joint, and the appearance of the head of the bone, which had been drawn up higher in the glenoid cavity, the crepitating sensation caused by the friction of the head of the humerus against the under surface of the acromion, the pain felt in the whole course of the biceps muscle, the difficulty experienced in abduction of the elbow from the side, the prominency of the head of the bone in front, almost to \u201c the amount of a partial dislocation,\u201d\u2014all these symptoms we have repeatedly noticed to belong to the affection of the shoulder joint which we have called chronic rheumatic arthritis, and all these have been present in patients who have had this disease in both shoulder joints at the same time, and in whom they could not by any means be referred to accident. Finally, before we leave our analysis of the symptoms of this case, we must not omit to allude to the author\u2019s own observation\u2014\u201c The patient being of a rheumatic habit, inflammatory action of that character was soon established in the joint, so that the peculiar symptoms of the injury were masked\nby those of general articular inflammation, which added greatly to the man\u2019s suffering, and to the difficulty of diagnosis.\u201d\nThe patient being, as we are told, of a rheumatic habit, or predisposed to this articular disease, it may be readily conceived that any injury this man, aged fifty-nine, might receive in the shoulder joint would be well calculated to give rise to the disease which we have called chronic rheumatic arthritis.\nAs to the anatomical examination of the joint, it will be recollected that the disease had been only six months established, and therefore that the more striking results of chronic rheumatic disease should be found was not to be expected. Those which were noticed, however, were such as might be supposed to represent the anatomical characters of chronic rheumatic arthritis of the shoulder in an early stage.\nAs to whether Mr. Soden\u2019s interpretation of his own case be the correct one, or the doubt we have ventured to express should be considered to have a just foundation, we must leave to the judgment of others, to time, and to the result of future investigations to determine ; but the subject must be confessed to be one of a truly practical nature, and therefore worthy of further inquiry.\nWe had written thus much on the subject of partial dislocation of the head of the humerus upwards, with displacement inwards of the long tendon of the biceps, when (on the 12th of August, 1848) an opportunity occurred to us of examining anatomically both shoulder joints of a patient who had died in the North Union Poor House the day before, who had been for eight years one of the severest sufferers the writer had ever known from chronic rheumatic arthritis in almost all his joints. The disease existed in an aggravated form in his hips and knees, wrists and elbows, and of late years began also to affect equally both shoulder joints. It was very remarkable that, on examining anatomically the shoulder joints in this case, we discovered the same displacement of the head of the humerus upwards, with dislocation of the tendon of the biceps inwards, as in Mr. Soden\u2019s case, in both shoulder joints, and with the dislocation of the long tendon in both shoulder joints in this case, which we shall now relate, were found associated the ordinary anatomical characters of chronic rheumatic arthritis in rather an early stage of the disease; while in the other articulations of this same individual the chronic rheumatic disease was in a very advanced state.\nCase. Charles Mailly, \u00e6tat. 48, had been a farming servant in the country,and was remarkable for his strength and activity. He was addicted to drinking ardent spirits to excess, and it was stated of him that he frequently lay whole nights in the open air in a state of insensibility from drunkenness. To these circumstances he attributed the origin of his disease, which disabled him from earning his bread ; he was therefore admitted into the poor house, in 1840. For the last five years he\nQ. Q 2","page":595},{"file":"p0596.txt","language":"en","ocr_en":"596\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nhas been altogether confined to his bed, as he could not stand upright, much less walk, when the writer visited him in August, 1847. His hips, knees, and elbow joints were semiflexed and rigid, his wrist extended, his fingers and toes presented the ordinary characteristic distortion belonging to rheumatic gout, or chronic rheumatic arthritis.* Although the shoulder joints in this case had lost much of their muscular covering, the deltoid and capsular muscles being in a state of atrophy, yet the bones of the articulation seemed much enlarged, and the heads of both humeri were evidently situated much above the level of the coracoid process. He did not complain of much pain in the shoulders ; the constant torture he endured in the right hip and both his knees quite distracted his attention from all minor suffering. He stated that he had a \u201c crackling \u201d sensation in all his joints whenever they were moved ; that his sufferings were influenced by the weather, and that he endured more pain during the frost of winter than at any other time. The patient died worn out by pain and irritative fever, attended with severe diarrhoea.\nPost-mortem examination. \u2014 Dr. R. Smith assisted the writer in this examination. As the body lay on its back on the table, the hips, the elbows, and knee joints were serai-flexeJ, and could not be extended, but they permitted of flexing to a very trivial degree. When any of the affected joints were moved, the characteristic crepitus, or crackling, so often alluded to, was elicited now as during life. The head of the os humeri of each side was drawn up much above the level of the coracoid process, and was preter-naturally advanced. Upon rotating the humerus, a marked crepitus was evident in these as well as all the other joints. On removing the integument over the right shoulder joint, the deltoid muscle was found pale, and forming a thin attenuated layer of muscular fibres covering the articulation. When this was removed, the sub-deltoid bursa was seen to be of a yellowish colour, and it had a fibrous appearance externally, like to a capsular ligament. When this bursa was freely cut into by an incision parallel to the margin of the acromion, its cavity was observed to be more capacious than usual. The posterior or inferior wall of the bursa was found to have identified itself with the external and superior part of the fibrous capsule of this articulation, and both seemed here to have become degenerated into thin cellular structure, which adhered to and formed a periosteal covering for the summit of the humerus near to the upper part of the great tuberosity. The capsular ligament was elsewhere somewhat thicker than natural, particularly at the upper and anterior part, where it seemed to have identified itself at its origin with the coraco-humeral ligament, which was much thickened. As to its attachment to the humerus, the\n* See Hand, Yol. II. p. 518. fig. 233.\ncapsular ligament, superiorly and posteriorly, was very short, having become adherent to the head of the bone before this capsule had reached its usual point of insertion into the anatomical neck of the humerus. Anteriorly and inferiorly the capsule descended on the neck of the humerus below its normal level (fig. 430.). When this ligament was cut into and examined posteriorly, several broad patches of adhesion were found to exist (as in Mr. Soden\u2019s case) between its internal surface and the head of the bone posteriorly, so that in these parts the synovial cavity was completely obliterated by the adhesion of the opposed surfaces of the membrane which lined the capsular ligament, and invested the posterior part of the head of the humerus, just as we find occasionally the pericardium partially adherent to the surface of the heart. When the capsular ligament was fully opened anteriorly, where it is covered by the tendon of the subscapu-laris, it was seen, more evidently than it could have been previously, that the head of the humerus had been placed habitually above the level of the coracoid process and the highest point of the glenoid cavity from which the long tendon of the biceps springs (fig. 430.). The tendon of the biceps lay entirely to the\nFig. 430.\nCase of Charles Mailly.\u2014 Chronic rheumatic arthritis. The long tendon of the biceps dislocated inwards, the head of the humerus partially displaced upwards, as in Mr. Soden\u2019s case. '.\ninside of the head of the humerus ; indeed, such was its position, that it might rather be said that the humerus was displaced outwards, and elevated above the level of the course of the tendon of the biceps, than that the latter was dislocated inwards. A semicircular groove marked the course of the tendon of this muscle as it arched across from the highest point of the glenoid cavity to the summit of the bicipital groove. The portion of the head of the humerus which was situated","page":596},{"file":"p0597.txt","language":"en","ocr_en":"597\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nabove the course of the tendon of the biceps was divested of all cartilaginous covering, was of a yellowish colour, and remarkably hard, and presented an appearance as if the summit of the humerus had been prepared for the polish of eburnisation, but as yet no ivory-like enamel had formed, because as yet bone had not come in contact with bone.\nThe head of the humerus was much enlarged and altered from its normal figure, particularly above, in the neighbourhood of the great tuberosity, which bulged out much externally ; the usual deep groove above, separating the tuberosity from the head, and here marking the anatomical neck of the humerus, was effaced.\nThe under surface of the neck of the humerus was furnished with a vast number of the synovial fimbriae before noticed by us when describing the anatomical characters of chronic rheumatic arthritis of the shoulder and other articulations. * These were in the recent state of a very red colour. The humerus seemed habitually to have remained in contact with the glenoid cavity, rotated inwards, and in this position these synovial fimbriae lay in contact with the inferior and broadest part of the glenoid cavity ; and it was very remarkable that wherever these red synovial fimbriae had been in exact apposition with the cartilage of incrustation of the glenoid cavity, exactly in the extent of the contact the cartilage had been removed, satisfactorily proving that these vascular fimbriae had been absorbing villous surfaces.\nThe glenoid articular surface presented but little worthy of notice, except a porous appearance where its cartilaginous investment had been removed by the absorbing villi, and the commencing state of disintegration of the glenoid ligament. The cartilage which remained on a portion of the head of the humerus, as well as that which still adhered to the surface of the glenoid cavity of the scapula, was rough, and altered from its natural state. The acromio-clavicular articulation of this side seemed enlarged externally, the periosteum about it thickened. When the articular surfaces were exposed, it was found that the cartilaginous covering had been removed, and that the articular surfaces were nearly double their normal size.\nIt is quite plain that the movements of the head of the humerus in the glenoid cavity in this case had been confined to those of a species of semi-rotation only ; the adhesions which were found to exist between the head of the humerus and the inner surface of the synovial membrane of the joint sufficiently suggest this, as well as the new form which the head of the humerus had assumed.\nThe left shoulder joint in almost every respect was symmetrically affected with the right, but particularly as regarded the dislocation of the tendon of the biceps, the existence of fimbriae, &c. &c., and therefore it does not require a separate description.\n* See Dublin Journal, vol. xv. p. 159.\nIt does not appear to us necessary to enter into any details here, relative to the condition the other articulations were found in. The lungs and other viscera were sound. Whether the patient ever had rheumatic fever or not we are not now able to learn ; but we may mention that upon looking to the state of the heart and its membranous coverings we found the pericardium adherent to the heart on all its surfaces except where it lay on the diaphragm. It seems to us plain that hereafter, when the tendon of the biceps shall be found displaced internail}', we are not at once to refer the dislocation to accident, but that inquiry must be made as to whether chronic rheumatic arthritis may not have been its cause. That the tendon of the biceps should, under the influence of changes which the structures of the joint may have undergone from disease, be thus thrown off the head of the humerus over which it arches, does not appear to us extraordinary, because we have known similar displacement of tendons under analogous circumstances ; indeed, we have generally found the extensor tendons of the fingers displaced, and the ligament of the patella and patella itself are sometimes thrown on the outer side of the external condyle of the femur when the knee joint has been the seat of chronic rheumatic arthritis.\nIn Mr. Soden\u2019s case accident may have had just so much to do with the displacement of the tendon, that the injury was the immediate exciting cause of the development of a local disease, a predisposition to which had previously existed in the constitution of the patient.\nThe writer regrets much that he has not as yet had any opportunity of examining the preparation of the shoulder joint presented by Mr. Soden to the museum of King\u2019s College, London ; but he requested his friend Dr. Macdowell, at the time in London, and who was familiar with the many preparations of chronic rheumatic arthritis contained in the Richmond Hospital Museum, to report to him his opinion on the appearances the preparation presented, and he writes to say, \u201c that from the partial examination he could make of the preparation he had only to remark, that the head of the humerus is considerably enlarged, and that the long tendon of the biceps, which has been dislocated internally, is in a state of atrophy.\u201d In these two additional circumstances, as w'ell as those already mentioned, the preparation resembles those of the shoulder joints in the case of Mailly.\nAlthough we have as yet said but little of any displacement of the head of the humerus occurring as a consequence of this chronic rheumatic disease, except in the direction upwards, and upwards and inwards, yet we would now call attention to facts to prove that the head of the humerus, under the influence of the changes induced by this disease in the structures of the shoulder joint, may suffer a partial displacement directly inwards under the coracoid process ;\nq Q 3","page":597},{"file":"p0598.txt","language":"en","ocr_en":"598\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\npartially downwards, enlarging the axillary margin of the scapula, so as to form a new glenoid cavity ; and lastly, that the infra-spi-natus fossa of the dorsum of the scapula may become the new situation, to which the head of the humerus may be transferred from the effects of chronic rheumatic arthritis of the shoulder.\nThe writer has after much investigation seen but two examples of this last displacement, and, curious to observe, these were in the right and left shoulder joint of the same individual.\nPartial dislocation of the head of the humerus inwards. \u2014 In the museum of the College of Surgeons, Dublin, we find a specimen presented by Professor Hargrave, which he considers one of partial luxation inwards from accident. The accidental origin of the affection, however, cannot be proved, as the history of the case is unknown ; and the specimen presents so many of the features of the chronic rheumatic disease combined with the partial luxation, that we are of opinion that Professor Hargrave\u2019s specimen cannot be considered the result of accident ; but that all the appearances it presents are the consequence of long established chronic rheumatic arthritis. We shall here give an abstract of Dr. Hargrave\u2019s case, referring for a fuller account to the Edinburgh Medical Journal.\nThe capsular ligament presented a perfect state of integrity along the superior and posterior part of the joint. It was very dense and strong, extending from the acromion process downwards and forwards towards thehumerus. When the capsule was opened on its internal aspect, the head of the humerus was seen to be in part external to the joint, and was divided into two unequal portions by a deep groove extending for the entire length of its head in a perpendicular direction. Of these two portions the internal and larger one passed a small distance beyond the corresponding edge of the glenoid cavity into the subscapular fossa, while the posterior and smaller one remained in the glenoid cavity, occupying its internal surface.\nThe groove now mentioned fitted on the inner edge of the glenoid cavity, which did not present its usual well defined border, but was rounded off, so as to present a thick lip, from the constant pressure and frequent motion of the humerus upon it. The head of the humerus in its superior aspect was in close apposition with the coracoid process, and had altered in a remarkable degree its form, which in place of being beaked and pointed, was much expanded, flattened and slightly hollowed.\nWhen the articulation was first opened, the tendon of the long head of the biceps could not be seen ; but on more particular examination it was found to have been ruptured, the portion connected with the muscle being intimately attached to the bicipital groove of the humerus, while the portion belonging to the glenoid cavity was much diminished in size,\nand presented a mere rudimental character in the capsular cavity.*\nWhen we carefully observe this specimen, we notice that it presents many of the general anatomical characters of the chronic rheumatic arthritis, these appearances being of course modified, as to the external shape of the surfaces, by the special peculiarity of the partial displacement which had in this case occurred.\nTiie head of the humerus was much enlarged and mis-shapen. It was found that a large portion of the new articular cavity for the head of the humerus lay on the subscapular fossa, but that a portion of the old glenoid cavity remained, and that the head of the humerus, divided into two surfaces, articulated with both the new and old glenoid cavity. The effects of friction during the movements which took place between the bifid head of the humerus and the double articular cavity, which corresponded to it, were such that perfect and complete ebur-nisation of parts of the contiguous surfaces took place. This last circumstance could not be said to amount to proof, that chronic disease rather than accident had caused the^ partial luxation. In addition to the ivory-like enamel, we find also that bony vegetations, or granular nodules of new bone, surround the outline of the new articular surface formed for the head of the humerus; and that small foreign bodies, like sesamoid bones, are seen bordering the edge of the articular cavity posteriorly. All these minor circumstances remind us of the anatomical characters we have found in examining cases of chronic rheumatic arthritis of the shoulder. The coracoid process, we are informed, had altered in a remarkable degree its form, which had become expanded, flattened, and slightly hollowed; in a word, it became articular, as we have often before found it to be, as the result of chronic rheumatic arthritis. The glenoid ligament (Professor Hargrave\u2019s case) was absent ; and the following description, which we may be excused for recopying, may well be applied, we think, to the ordinary condition of the tendon of the biceps in most of the cases of chronic rheumatic arthritis of the shoulder.\n\u201c When the articulation was first opened, the long tendon of the biceps could not be seen, but on more particular examination it was found to have been ruptured, the portion connected with the muscle being intimately attached to the bicipital groove of the humerus, while the portion belonging to the glenoid cavity was much diminished in size, and presented a mere rudiment.\u201d\nWe have already made the remark, that when the shoulder joint is the seat of chronic rheumatic arthritis, the neighbouring acromio-clavicular articulation is frequently affected with this same disease. Now, in carefully examining Professor Hargrave\u2019s specimen, we shall find that not only do the anatomical characters which belong to chronic rheumatic\n* See Catalogue of the Museum of the R. C. of Surgeons, Dublin, vol. ii. p. 397. Edinburgh Medical and Surgical Journal, for October, 1837.","page":598},{"file":"p0599.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t599\narthritis exist in this shoulder joint, but also that the aeromio-clavicular articulation in the same specimen is enlarged externally; and that, on examining it internall}', it presents undoubted traces of this chronic rheumatic disease. Upon the whole, therefore, we feel convinced that this specimen produced by Professor Hargrave as an example of a case of partial luxation inwards, the result of accident, does not really afford any proof that external injury was the cause of the partial luxation.\nIn thus differing from Professor Hargrave, we would make the same remarks which we have already made in allusion to Sir A. Cooper\u2019s case, at page 591. of this article. The progress of science will soon settle the question.\nPartial displacement of the head of the humerus downwards has been observed to be the result of chronic rheumatic disease of long standing ; but after much diligent inquiry in museums and in books, I can find but two well-marked specimens of this morbid change. The most remarkable of these specimens is a left scapulo-humeral articulation, which is contained in the museum of the College of Surgeons, Dublin. The history of the case is unknown : the preparation formed part of the collection presented by Dr. Kirby to the College of Surgeons in Dublin. The head of the left humerus in this specimen is greatly enlarged, and a proportionate glenoid cavity has been formed to receive it. The head of this bone had descended so much beneath its ordinary situation, that a new glenoid cavity had been formed to receive it on the axillary border of the scapula. The lower part of the old glenoid cavity was still partially occupied by the enlarged head of the humerus, but the new addition to the cavity extends downwards for the space of an inch and half below its ordinary situation. The new glenoid cavity is enamelled on its surface, and enlarged on its posterior margin by several irregular-shaped bones of new formation. The capsular ligament in this case has been partly ossified.*\nIf we look over the engravings in Sandi-fort\u2019s Museum Anatomicum, we shall find, we think, a specimen of partial displacement of the head of the humerus downwards, the result of this chronic rheumatic disease. The writer of the catalogue considers the specimen to have been the result of accident, and has appended a history to the case, giving an account of somewhat equivocal symptoms. Whether these symptoms,\u2014such as extensive effusion into the cavity of the joint, of crepitus having been felt on the motions of the bones on each other,\u2014were the result of accident or of disease, their origin is referred to accident. When we carefully compare the engraving with what we have seen of other specimens of this disease elsewhere, we must, we think, come to the conclusion, that this\n* See Catalogue of the Museum of the College of Surgeons, Dublin, pp. 406\u2014905. &c. See also plate IX. fig. 7. of a work on chronic rheumatic arthritis, shortly to be published by the writer ; illustrated by lithographic drawings of natural size.\nexample adduced by Sandifort must be considered as the result of chronic rheumatic\nFig. 431.\nScapula and portion of the clavicle connected to it, viewed externally.*\na, glenoid cavity ; h, a fragment of bone apparently of new formation ; c, anterior part of acromion separated from the spine of the scapula and reunited to it ; d, extremity of the coracoid process ; e, clavicle adhering to the acromion broken off from the spine of the scapula. The acromion process was depressed, and \u201c omnem motum clavicul\u00e6 seque-batur.\u201d (After Sandiford.)\narthritis of long standing, with partial displacement of the altered head of the humerus downwards {fig. 431.). Upon looking at the wood-cut we notice the acromio-clavicular articulation enlarged as if from chronic rheumatic disease. The acromion process is divided into two portions ; a phenomenon we have so frequently noticed to accompany this disease of the shoulder joint (see p. 587.). We also notice the additional portions of bone of new formation attached to the capsular ligament so common in this disease, and the addition of an osseous margin to the glenoid cavity ; all these circumstances, so well seen in the original drawing to be found in Sandifort\u2019s work as large as nature, we have attempted, in a reduced form, to repeat here.\nFinally, the head of the humerus may be not only displaced partially upwards as the result of this chronic rheumatic disease, partially inwards, and, as we have just proved, also partially downwards, but the most remarkable abnormal appearances the writer has witnessed from this chronic disease, has been in two specimens contained in the Museum of St. Bartholomew\u2019s Hospital, in which it will be found that the head of the humerus, which had been affected by this chronic disease, was thrown completely backwards on the dorsum of the scapula. In this case the displacement was double, and two new glenoid cavities had\n* Diminished drawing from one in Sandifort\u2019s Museum Anatomicum, vol. iv. table 25.fig. 2.\nQ Q 4","page":599},{"file":"p0600.txt","language":"en","ocr_en":"600\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nbeen formed for the reception of the enlarged heads of the humeri behind the glenoid cavities, and partly beneath the bases of the spines of the scapulae just where the head of the humerus has been found to rest in the ordinary dislocation backwards from accident ; but in this case, although the history was unknown, that these appearances were not the result of accident is almost certain, as similar abnormal appearances are observable on each side. The notice of this preparation in the catalogue of the museum is as follows (p. 108\u20143*2.) : \u2014 \u201c The bones of both the shoulder joints of an adult. In each joint there has been \u2018 ulceration,\u2019 or such absorption as occurs in chronic rheumatism of the articular surface of the head of the humerus, and the glenoid cavity. The heads of the humeri are flattened and enlarged by growths of bone around their borders; and the glenoid cavities, enlarged in a corresponding degree, and deepened, extend backwards and inwards to the bases of the spines of the scapulae. The articular surfaces, thus enlarged, are mutually adapted, and are hardened, perforated, and in some parts polished and ivory-like. The changes of structure are symmetrical, except in that the articular surfaces of the right shoulder joint are more extensively polished than those of the left.\u201d\nSection II. \u2014 Accident. \u2014 The principal accidents the shoulder joint and the bones in its immediate vicinity are liable to, are fractures and luxations.\nFractures.\u2014A fracture may traverse the acromion, the coracoid process, or detach the glenoid articular portion of the scapula from the body of this bone by passing directly across the neck of the scapula.\nA. Fracture of the acromion process. \u2014 A fracture of the acromion process may be caused by the fall of a heavy body on the superior surface of the acromion ; but this accident most usually occurs in consequence of falls in which the patient is thrown from a height on the point of the shoulder. The fracture of the acromion will be generally found to have taken place at a point behind, and within, the junction of the clavicle with this bony process ; its direction we always observe to be in the original line of the junction of the epiphysis with the rest of the bone. In this accident, if the distance be measured from the sternal end of the clavicle to the extremity of the shoulder, it will be found lessened on the injured side. Considerable ecchymosis of the shoulder may be expected soon to succeed the injury, and the patient will be unable to elevate the arm. Sometimes the periosteum of the acromion is not torn, and then, although the fracture of the bone has been complete, there is no displacement of the fragments. If, however, this fibrous investment of the acromion, above and below, be completely torn across, the acromion process will be found to be depressed, because it will be pulled down by the weight of the extremity and contraction of the deltoid muscle. The portion of the acromion thus detached is\ngenerally very moveable, following the clavicle whenever the arm is moved. This accident is best recognised by the surgeon first taking hold of the elbow of the affected side, and elevating the whole arm perpendicularly. \u201c Having thus restored the figure of the part, he places his hand upon the acromion, and rotates the arm, when a crepitus can be distinctly perceived at the point of the spine of the scapula.\u201d *\nFractures of the acromion unite by bone, sometimes with much deformity, arising from ossifie depositions, which however do not, after a time, interfere much with the motions of the arm. This union has sometimes been known to take place in forty-eight days, and in other cases in a much shorter time. The union, however, is frequently only ligamentous. Sir A. Cooper speaks of a false joint being occasionally the result of a fracture. Malgaigne, alluding to a case in which a false joint was the consequence of a fracture of the acromion, says that the fractured surfaces presented a polished appearance, and were covered with an ivory deposit, the effects of friction. He adds, that the union was not simply a ligamentous connexion, but that an arthrodial false joint had been formed. In all the specimens of this fracture examined by Malgaigne, the superior border of the fracture was surmounted with small bony crests of new formation, of which the more considerable number grew from the scapular portion of the acromion, while those produced from the detached extremity of this process were but few, no doubt in consequence of its lesser degree of vitality. This remark of Malgaigne coincides with the observations to be found in Sir Astley Cooper\u2019s Work, that the disposition to ossifie union is very weak in the detached acromion. Malgaigne, however, refers to a preparation in the Museum of Dupuytren, in which the external fragment possessed a thickness almost double that of the portion of bone from which it had been detached. This thickness the writer of the Catalogue of the Museum thought was caused by an overlapping of the fragments of the broken portions ofthe acromion ; but Malgaigne supposes it to have arisen from simple hypertrophy of the detached fragments.\nB. Fracture of the coracoid process \u2014 is a rare accident, and when it does occur, it is generally the result of a severe injury, in which the fracture of the bone is the least of the evils attendant on the compound injury. ThusBoyerf gives us the account of a fracture of the coracoid process produced by the blow of a carriage pole ; the patient died in a few days afterwards, in consequence of the severe contusion he suffered at the moment of the accident. The coracoid process, when fractured at its basis, is pulled downwards and forwards by the lesser pectoral coraco-bra-chialis and short portion of the biceps muscle. We are told}; that if the contusion accompanying this accident be slight, we can seize\n* Sir A. Cooper.\nf Maladies Chirurgicales.\t| Sanson.","page":600},{"file":"p0601.txt","language":"en","ocr_en":"I\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t601\nthe fragment between the finger and thumb, and prove at once the mobility of the fragment and the existence of crepitus.\nIf, says Boyer, the soft parts were in the natural state, we could easily recognise the fracture of the coracoid process, when it has occurred ; but so much force is necessary to produce this fracture, that the considerable swelling which always accompanies it, prevents us from being able to recognise the characters of the injury, so that it is not generally ascertained except in the dead body.\nC.\tFracture of the neck of the scapula. \u2014 By a fracture of the neck of the scapula is meant a fracture through the narrow part of the bone immediately beneath the notch on the coracoid margin of the scapula, by which the glenoid or articular portion of the bone, together with the coracoid process, becomes detached from the rest of the scapula ; the head of the humerus falls into the axilla, with the glenoid cavity attached to it by means of the capsular ligament.\nSir Astley Cooper says the diagnostic marks of this injury are three : first, the facility with which the parts are replaced ; secondly, the immediate fall of the head of the bone into the axilla when the extension is removed ; and thirdly, the crepitus which is felt at the extremity of the coracoid process when the arm is rotated. The best method for discovering the crepitus is as follows ; let the surgeon\u2019s hand be placed over the top of the shoulder, and the point of his forefinger be rested on the coracoid process ; the arm being then rotated, the crepitus is distinctly perceived, because the coracoid process being attached to the glenoid cavity, and being broken off with it, although itself uninjured, crepitus is communicated through the medium of that process. We believe this accident to be exceedingly rare.\nD.\tFracture of the superior extremity of the humerus. \u2014 The superior extremity of the humerus may be broken across, in the line of its anatomical neck, or through the head of the bone above this oblique line. In both cases the fracture will be intra-capsular.\nSecondly, the fracture may be extra-capsular, passing through the tubercles ; beneath the anatomical neck of the humerus, yet above the line of the junction of the epiphysis, with the shaft of the bone.\nThirdly, a fracture may traverse the humerus in the line of junction of the epiphysis with the shaft of this bone, or close to this line.*\nFourthly, the humerus may be fractured in the part called the surgical neck, beneath the line of junction of the epiphysis with the shaft.\n1. Intracapsular fracture of the humerus. \u2014 We find on record fractures of the head of the humerus, which were altogether intra-\n* Dr. R. Smith has exposed well the error of confounding together as the same the line of the anatomical neck of the humerus, and the line by which the superior epiphysis is united with the shaft of the bone.\narticular ; and in these cases the head of the bone was separated at the proper anatomical neck. Boyer states he has met with many such cases, most of which were fatal from the severity of the injuries which accompanied the fracture. He mentions the case of a woman who lived for seven days, after having received one of these severe injuries. On making a post-mortem examination of the shoulder, the separated head of the humerus had suffered a great loss of substance ; it was hollowed out as to its fractured surface, so as to represent a complete hollow cap or \u201c calotte.\u201d It seems to be the opinion of many, that in cases of intra-capsular fractures of the superior extremity of the humerus, unless some portions of synovial membrane and periosteum remain unbroken, no bony consolidation can occur. This may be true as to some fractures ; but, on the other hand, we have evidence of cases in which the head of the humerus must have been completely broken, as well as all its membranous coverings severed ; and yet perfect reunion of the portion of bone which had been detached was established ; but in these cases it is to be observed, that impaction, to a certain degree, of the head of the humerus into the shaft, had occurred.\nThe possibility of the consolidation, by bony union, of a fracture of the anatomical neck of the humerus had been long doubted. Upon this subject, J. Cloquet observes : \u201c I have, some years ago, made known a case of fracture of the humerus through its anatomical neck, which had been perfectly united. Re\u00efchel had before published a similar fact : sometimes the consolidation in these cases would appear to be accomplished by the agency of the inferior fragment, from which spring up stalactiform productions, which surround and encase the superior fragment.\u201d He adds, \u201c we have also met with examples, in which consolidation did not take place. In these last cases, the head of the bone has been found to have been hollowed out, by contact with the inferior fragment, so that a false joint had been formed in the situation of the fracture; and the superior fragment, by its inferior surface, represented a hollow cup, or \u2018calotte articulaire.\u2019\u201d*\nThe following cases will show that a fracture through the anatomical neck of the humerus may occur, in which the head of the bone may be subsequently impacted into the shaft, and be then consolidated by bony union.\nA female, aet. 47, was admitted into the Richmond Hospital, under the care of the late Dr. Macdowell, for an injury of the humerus, the result of a fall upon the shoulder. The case has been merely entered in the Hospital Case-Book, \u201c a fracture of the humerus.\u201d Five years afterwards, the woman was admitted into the same hospital, under the care of Mr. Adams, for another injury, a fracture of the thigh, of which she died. Post mortem, the shoulder was care-\n* Cloquet, Dictionnaire de Medicine, article Frac-\nTURE.","page":601},{"file":"p0602.txt","language":"en","ocr_en":"602\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nfully examined. The arm was slightly shortened. The contour of the shoulder was not as full nor as round as that of its fellow, and the acromion process was more prominent than natural. Upon opening the capsular ligament, the head of the humerus was found to have been driven into the cancellated tissue of the shaft, between the tuberosities, so deeply as to be below the level of the summit of the great tubercle ; this process had been split and displaced outwards; it formed an obtuse angle with the outer surface of the shaft of the bone. The distance to which the superior fragments had penetrated into the shaft is well seen in the wood-cut (Jig. 432.)\nFig. 432.\nThe head of the humerus impacted.\nNelaton and Smith* have alluded to cases of intra-capsular fractures of the head of the humerus, in which the detached head of the bone became inverted on itself, and was thus impacted into the shaft of the humerus. Nelaton observes :\u2014\u201cDr. Dubled showed me a specimen, in which the cap which the summit of the head of the humerus forms had been broken from the shaft, and afterwards inverted on itself, so that the broken surface of the upper fragments looked upwards and inwards, while the smooth polished articular part looked downwards, and in this position w as buried into the shaft or inferior fragment. Notwithstanding this displacement, consolidation had taken place.\u201d The superior fragment was enveloped by stalactiform produc-\ntions, which had sprung up from the shaft of the humerus.\nIn the year 1843, Dr. Robert Smith laid before a meeting of the Pathological Society of Dublin, a remarkable specimen of a fracture of the neck of the humerus, in which the head of this bone was driven into the shaft, splitting asunder the bone in the situation of the tuberosities. The subject of the observation was a woman, aet. 40, who, many years before her death, had met with the accident. On proceeding to make the post-mortem examination of this case, it was remarked that the acromion process was prominent ; the deltoid flattened ; the arm was shortened ; the glenoid cavity could not be felt ; the shaft of the humerus was drawn upwards and inwards, so as to be almost in contact with the coracoid process ; the motions of the joint were limited ; and the capsular muscles atrophied.\nDissection. \u2014 When the soft parts were removed, and the capsular ligament was opened, the traces of a fracture having long ago passed through the anatomical neck of the humerus were obvious. The head of the humerus was solidly united to the shaft. But, upon examining further, what struck Dr. Smith as very remarkable was, that the head of the humerus was found reversed, or turned upside down, in the articulation ; or, in other words, the fractured surface was turned upwards towards the glenoid cavity, and the cartilaginous articulating surface turned downwards, as in Nelaton\u2019s case, towards the shaft. The only explanation of this circumstance which can be given is, that the head of the bone, at the time of the accident, had been completely separated from the shaft by a fracture through the anatomical neck ; that thus rendered free in the interior of the joint, the head of the bone became inverted on itself, and was thus subsequently driven into the cancellated structure, between the tubercles.\nIt appears that in the Museum of the College of Surgeons of Dublin, a third specimen of this complete inversion of the upper fragment of the broken humerus is to be found.*\n2. Extra-capsular fracture through the tubercles.\u2014 The fracture may be extra-capsular; passing through the tuberosities beneath the anatomical neck of the humerus, yet above the line of the junction of the epiphysis, with the shaft, of the bone.\nThis fracture is usually the consequence of severe falls on the outside of the shoulder ; it may occur at all ages, but is most frequently met with in elderly persons. The line of the lesion may be transverse, but usually the bone is broken into many fragments. There is some shortening of the arm, but very little if any transverse displacement of the bony fragments. The long tendon of the biceps, in front, and the strong fibres proceeding from the bony attachment of the capsular ligament and capsular muscles, will retain the fragments in their place. The shortening is the result of the mutual impaction into each other of\n* Dr. K. Smith\u2019s work on Fractures.\n* See Dr. K. Smith\u2019s work on Fractures.","page":602},{"file":"p0603.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t603\nthe superior and inferior fragments. As the fracture thus generally exists without any very obvious displacement of the fragments, and as it is usually accompanied by much swelling of the shoulder joint, the diagnosis may be very obscure.\nSymptoms. \u2014 The patient will complain of severe pain in the shoulder, which is much increased by the least pressure, or by communicating any movement whatever to the arm ; and he cannot, by any voluntary effort of the muscles of the injured arm, elevate it ; on making a methodical examination soon after the accident has occurred, crepitus can be elicited, As to the degree of power which the patient possesses of moving his arm in these cases, some variety may be noticed, particularly if some days have elapsed since the receipt of the injury.\nThe following case of fracture through the tuberosities of the humerus was very recently under observation at the Richmond Hospital, and may be here adduced, to show the difficulty that may occur in making our diagnosis if the case is not seen soon after the occurrence of the accident.\nCase. \u2014 Mary Trainor, set.60, was admitted into one of Mr. Peile\u2019s wards in the Richmond Hospital on the 19th of May,\" 1848. She complained much of the left shoulder, on which she had fallen fourteen days before. She had never used her arm since the accident, nor left it unsupported. The patient pointed to one part close to the head of the humerus anteriorly, which was particularly painful, and here a small bony projection was detected, whether a spicula of bone or a small exostosis could not be known. She could elevate, or abduct her arm some inches from her side, and could rotate it freely herself, without these movements causing her any pain. Although many examinations had been made since her admission into the hospital, no satisfactory evidence of crepitus could be detected ; there was some tumefaction, and heat showing inflammation of the shoulder joint. She died suddenly of apoplexy on the fourth day after her admission.\nPost-mortem. \u2014 Before the shoulder joint was examined, it was ascertained by careful measurement from the posterior angle of the acromion to the outer condyle of the humerus, as well as from the scapular extremity of the clavicle to the same point below, that the left or injured arm was fully one quarter of an inch shorter than the right. On removing the muscles and their tendons, a fracture was seen to have traversed the superior extremity of the humerus : the line of this fracture was somewhat irregular ; posteriorly it passed along the basis of the head of the humerus, or nearly as high as the level of the anatomical neck, and anteriorly along the basis of the lesser tuberosity, which was thus left attached to the head, while the greater tuberosity was detached, and broken into fragments ; and it appeared as if this last was the mechanical result of the impaction of the head into the cancelli of the shaft of the bone ; the\namount of this impaction was to the extent of one quarter of an inch. The synovial membrane was perforated or punctured in one or two points by spicul\u00e6 of the broken humerus, and this membrane showed decided traces of having been the seat of inflammatory action. The cartilaginous covering of the head of the humerus seemed to have been somewhat thinned \u2014 the result of the inflammation which had engaged the joint more or less ever since the occurrence of the accident.\nThe diagnosis in this case was very difficult, for there was some swelling and decided inflammation of the shoulder joint: fourteen days had passed since the accident occurred, and no crepitus, although carefully sought for, could at this period be detected. Apparently self-persuaded that no fracture existed, the woman repeatedly showed to Mr. Robert Macdonnell (the resident pupil, who had immediate charge of the case) how freely she could rotate the injured humerus ; she could also abduct the elbow some inches from her side. A fracture through the superior part of the humerus was suspected ; but as there was no obvious displacement of the fragments, the principal indication seemed to be to reduce the inflammation of the shoulder joint, and this line of practice was pursued. The expedient of making a comparative measurement as to the relative length of the two arms was not thought necessary as an aid in the diagnosis of this case; yet the result of th s experiment would have shown in the living as it did subsequently in the dead body, a decided shortening of the left arm to the amount of a quarter of an inch, an observation which would no doubt have confirmed the idea already existing in the minds of the attendants, that a fracture of the humerus existed, as well as an inflammation of the shoulder joint.\n3. Fracture of the superior extremity of the humerus through the line of junction of the epiphysis with the shaft of the bone, or close to this line.\nThis is a species of fracture which not un-frequently occurs in early life. In the old subject we occasionally witness cases of fracture in the same situation. This accident is so far unlike that last adverted to, that while in the former there is no displacement, the latter accident is attended with considerable deformity. We may make this general remark with respect to fractures above the line of junction of the epiphysis, whether the fracture be extra-capsular or intra-capsular.\u2014 There is little or no deformity, and crepitus (a symptom of fracture, the possibility of eliciting which usually exists), and shortening to a small amount of the length of the humerus, are the only positive signs to which we can refer to establish our diagnosis ; but when a fracture of the humerus, either at the line of junction of the epiphysis with the shaft of the bone, or below this line in the surgical neck, occurs, then much displacement of the fragments may generally be observed.\nSir A. Cooper has described an assemblage","page":603},{"file":"p0604.txt","language":"en","ocr_en":"601\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nof symptoms belonging to a class of cases of fracture of the superior extremity of the humerus, which we have no doubt he conjectured to belong to the separation of the superior epiphysis from the shaft of the humerus in the young subject. In the adult, a fracture through the original line of junction of the superior epiphysis with the shaft of the humerus would be attended with nearly similar symptoms. In alluding to the injury in question, Sir A. C. observes, that in children it is the result of falls upon the shoulder. The signs of it are as follow : \u2014 The head of the bone remains in the glenoid cavity of the scapula, so that the shoulder is not sunken as in dislocation ; when the shoulder is examined a projection of bone is perceived upon the point of the coracoid process, and when the elbow is raised and brought forward this projection is rendered particularly conspicuous. By drawing down the arm the prominence is removed, but it immediately re-appears upon ceasing to make the extension, and the natural contour of the shoulder is lost.\nAll the movements of the shoulder joint are painful, and the patient cannot raise the arm unless by the aid of the other hand. The elbow is with difficulty withdrawn from the side, and the arm requires support. Sir A. Cooper adduces a case illustrating the above symptoms in a child \u00e6t. 10, who had fallen on the shoulder into a sawpit the depth of which was eight feet.\nThe writer has witnessed many examples of fracture of the humerus in the line of junction of the superior epiphysis with the shaft of the bone, or in the immediate vicinity of this line.\nIn these cases the youth of the patient, and the situation of the fracture, led him .o conjecture that a separation of the superior epiphysis of the humerus had occurred ; but he had no opportunity of ascertaining anatomically the true nature of the lesion.\nThe principal deformity noticed by the writer in these cases is attempted to be delineated in (fig. 433.), the representation of one of the plaster casts which he has preserved of one out of many of these cases. The prominence here delineated is found to be owing to a very remarkable projection forwards of the upper extremity of the inferior fragment of the humerus. This was best seen by viewing the shoulder in profile, or sidewise. The antero-posterior measurement of the shoulder was much increased. Sir A. Cooper, in reference to the cases he has seen of this kind, observes, that when the shoulder is examined a projection of bone is perceived \u201cat the front of the coracoid process in four cases which the writer has witnessed, the projection of bone formed by the superior extremity of the lower fragment of the humerus was situated exactly in the centre of a line stretching anteriorly from the acromio-clavicular articulation to the lower margin of the anterior fold of the axilla. This remarkable projection of the bone, formed by the lower fragment, was in two cases engaged in the deeper layers of the integuments covering the deltoid_ muscle\nnear to its anterior margin, and hence the deltoid muscle must have been itself perforated. In these latter cases it was found impossible to disengage the bone from its faulty position, or from the fibres of the deltoid\nFig. 433.\nCase of C. Austin. Fracture of the humerus in or near the line of junction of the epiphysis.\nmuscle, and deeper layer of the integuments. The following case of the above description has been recently seen by the writer.\nCase.\u2014Fracture through the humerus immediately below the tuberosities, or through the onginal line of junction of the epiphysis and shaft of this bone.\u2014 Charles Austin, aged 14 years, on the morning of the 12th April, 1848, fell from a height of seven feet off a ladder, and was thrown on the posterior part of his left shoulder on uneven ground. He was not seen until next morning, when the injured shoulder presented the following appearances * : \u2014 \u201c There was a great deal of ecchymosis and swelling about the joint ; the acromion process appeared prominent, and in viewing the shoulder sidewise the measurement of its antero-posterior diameter appeared greatly increased. The patient supported the hand and fore-arm of the injured arm with the opposite hand ,* the elbow was slightly abducted, but it could be readily pressed against the side. He could not himself make the least effort to move the arm, and the attempt to raise it from the side, or to deprive it, even for a moment, of the support of the right hand, was productive of much pain. On placing one hand over the joint, and rotating the humerus with the other,\n* For the notes of this case, the writer is obliged to Mr. W. Court, resident surgeon to Steeven\u2019s Hospital, with whom he examined it.","page":604},{"file":"p0605.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\na distinct crepitus could be perceived. The head of the bone could be felt in the glenoid cavity, and when the shaft of the humerus was rotated no motion was communicated to the head. On the seventh day after the accident all swelling had subsided, and the appearances noted were as follows ; \u2014 On viewing the shoulder in front, a very remarkable angular projection of bone forwards is observed. This prominence is very near the anterior margin of the deltoid muscle, and near the centre of a line drawn from the scapular end of the clavicle to the margin of the anterior wall of the axilla. This projection is evidently the abrupt termination of the upper extremity of the lower fragment of the humerus ; every movement communicated to the shaft of the bone also moves this projecting point, a little below, and to the outside of which, an indentation or slight puckering of the skin is observable. This last we can readily suppose has been produced by the lower fragment having perforated the deltoid muscle, and engaged itself in the deeper layer of the integument.\n\u201c On viewing the joint sidewise or in profile, the posterior angle of the acromion projects much behind, while the abrupt prominence already mentioned, formed by the shaft of the humerus, is very salient in front; so that in this side view, the antero-posterior diameter of the joint is seen to be much increased. The long axis of the arm is directed from above downwards and backwards, very slightly also outwards. By measurement from the acromion to the external condyle of the humerus, the injured side is found to be a quarter of an inch shorter than the opposite. The patient cannot himself perform any of the movements of the shoulder joint, except that of rotation to a small extent, but can permit the humerus to be freely moved by another. Although crepitus was evident at first, now, seven days having elapsed since the accident, it can no longer be elicited.\n\u201c May Vlth. \u2014 Nearly a month has passed since he received the fall ; he has regained considerable power of motion over the left arm, can even raise his hand to the top of his head. On the 6th of June he left the hospital, being able to use his arm ; the deformity, consisting in the abrupt projection of bone, was somewhat reduced.\u201d\n4. Fracture of the surgical neck of the humerus below the tuberosities and original line of junction of the epiphysis with the shaft of the tone.\u2014In this case there is much deformity to be observed. The head and tuberosities form the superior fragment, which in general remains in its natural situation, while the upper extremity of the lower fragment, which last is constituted by the principal part of the shaft of the humerus, is drawn upwards and forwards under the pectoral muscle. When the arm is grasped at the elbow by the surgeon, and pushed upwards, the upper extremity of the broken shaft of the humerus is made to project at the inner side of the coracoid process of the scapula, and is felt to roll whenever the arm is rotated.\nFracture of the humerus in its surgical neck occurs at different heights in this bone. The most common situation for the fracture is where the spongy portion of the bone unites with the rest of the shaft ; and here it is that the humerus, considered anatomically, would seem to be the least capable of resisting external violence. The direction of the fracture is generally transverse, more rarely is it oblique, and, in this last case, the obliquity is generally in a line from without inwards, and from above downwards, parallel to the line of the anatomical neck of the humerus, but below it, and the nature of the displacement is variable. Most frequentlv the inferior fragment is drawn inwards towards the axilla ; but the inferior fragment has been also observed to be displaced and become prominent in other directions. Desault has seen it thrown backwards ; Dupuytren, Pa-letta, Duret, and others, have seen it raised up, and even perforate the deltoid muscle outwards ; finally, it more frequently still has been observed to become prominent in front towards the coracoid process.\nMons. Gely has, in the Journal de Chirurgie, mentioned a case of fracture of the surgical neck of the humerus, in which the fracture was oblique, the obliquity running parallel with, but below, the anatomical neck of the humerus. The inferior fragment had perforated in front the deltoid muscle, very near to the interstice which separates the deltoid from the pectoral muscle; the arm was shortened an inch. These observations refer to the altered position of the inferior fragment, resulting from a fracture through the part of the humerus called the surgical neck. It is said that usually the superior fragment remains in its normal position in these fractures, but this is not always the case. Malgaigne narrates a case of a man, aged 78, in whom the humerus was fractured\u2019 transversely in its surgical neck, about an inch and a half above the folds of the axilla. There was an overlapping of the bones; the injured arm was consequently one inch and a half shorter than the other. The fracture during life could not be reduced; he died on the twenty-sixth day after the injury. The inferior fragment was drawn inwards and forwards, and indeed during life had raised up the soft parts towards the union of the deltoid and pectoral muscles, more internally than the situation of the coracoid process; the overlapping of the fragments was to the amount already mentioned. The fracture through the humerus was beneath the tuberosities, the longitudinal axis of the lower fragment was in the direction upwards and inwards, and the longitudinal axis of the upper fragment was directed downwards and outwards. In a word, the superior fragment was in a position which would correspond to the highest elevation of the arm in the normal state; and the inferior, on the contrary, was in a position which corresponded to its greatest depression.\nDislocations.\u2014The head of the humerus","page":605},{"file":"p0606.txt","language":"en","ocr_en":"606\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nmay be dislocated from the glenoid cavity of the scapula as the result of accident, in three different directions ; namely, downwards and inwards, into the axilla.\nSecondly, forwards and inwards.\nThirdly, backwards on the infra-spinatus fossa, or on the dorsum of the scapula.\nPartial dislocations, or subluxations of the head of the humerus, as the result of accident, have been much spoken of, and accounts of such supposed accidents are to be found in the works of practical surgeons. While we would not deny that cases deserving the name of partial luxations of the head of the humerus do occasionally present themselves to the surgeon, in our experience all such cases have been found, on strict inquiry, not to have been the direct effect of accident, but the result of chronic disease, or of congenital malformation of the shoulder joint. And we here formally deny that the case of partial luxation of the head of the humerus, as the result of accident, has ever been satisfactorily proved, either in the living or the dead subject.\n1. \u2014 Dislocation downwards and inwards into the axilla.\u2014The dislocation of the humerus doivnwards is unquestionably the most common, and is generally produced by a fall on the elbow, or palm of the hand, the arm being at the time extended from the body. The humerus, therefore, immediately prior to the accident, would be so related to the glenoid cavity as to form with it an acute angle inverted ; and the head of the bone, thus gliding from above downwards, is forced violently against the lower part of the capsule, which is stretched and lacerated so as to allow the head of the humerus to escape ; this result is further aided by the weight of the body, and by the contraction of the great pectoral, latissimus dorsi, and teres major muscles. The new position assumed by the head of the dislocated bone is on the inner side of the anterior margin of the scapula, between the subscapular muscle anteriorly, and the long head of the triceps, posteriorly. The pectoralis major, latissimus dorsi, and teres major muscles act upon the arm as on a lever, of which the elbow is the fulcrum, and the point of resistance is at the articulation ; while the elbow rests on the ground, and the weight of the body presses on the lower part of the capsular ligament of the shoulder joint, the muscular folds of the axilla being instinctively thrown into violent action, make an effort to approximate the arm to the side ; but as these muscles cannot move the lower extremity of the humerus, on account of the elbow resting on the ground, the head of the bone becomes the moving point, and bursts through the lower part of the capsular ligament, and is dislocated into the axilla. Dislocation downwards may, according to some authors, be produced by a violent blow on the outer part of the shoulder, below the acromion ; but in that case it is often complicated with fracture of the scapula or humerus. It is further possible that it may result from\nsimple muscular action, as in the act of lifting a heavy weight, or during an attack of epilepsy ; in either case a violent effort is required, whether the effect be attributed to the agency of the deltoid, in depressing the head of the bone, or, as Boyer supposes, to the action of the great pectoral, latissimus dorsi, and teres major muscles, simultaneously cooperating with the elevators of the arm.\nSymptoms. \u2014 The usual signs of this dislocation into the axilla, are the following : \u2014A hollow is formed below the acromion, in consequence of the displacement of the head of the humerus from the glenoid cavity. The deltoid muscle is flattened and dragged down with the depressed head of the bone, so that the natural roundness of the region of the shoulder is lost. The arm is somewhat longer, and the anterior fold of the axilla is deeper than natural, because the new situation occupied by the head of the bone on the subscapular fossa of the scapula, is below the level of its natural position in the glenoid cavity (y?g. 434.). The elbow is with difficulty made to touch the patient\u2019s side; this movement is the source of much pain, as it causes the head of the dislocated bone to compress the nerves in the axilla; and upon this account the patient himself supports his arm at the wrist with the other hand. The head of the os humeri can be felt in the axilla, but not except the elbow be considerably removed from the side. \u201c I have,\u201d says Sir Astley Cooper, \u201c several times seen surgeons deceived in these accidents, by thrusting the fingers into the axilla, when the arm is close to the side, when they have directly said, \u2018 This is not a dislocation ; \u2019 but upon raising the elbow from the side, the head of the bone could be distinctly felt ; for that movement throws the head of the bone downwards, and more into the axilla.\u201d The surgeon finds some difficulty in overcoming the fixedness of position of the humerus in its new situation. The patient\u2019s voluntary power of abduction of the arm, and of rotation, are lost ; the motion of the limb forwards and backwards is preserved. There is great difference in respect to the movements which can be communicated to the limb, depending on the tone of the muscles ; because, if the muscles are relaxed and feeble, from age or any other cause, the surgeon may be able to move the patient\u2019s arm freely, and to raise it up to the head, and even press the elbow close to the side. On moving the limb, a slight crepitus will sometimes be felt, but by a continuance of the motion, this soon ceases ; the crepitus, however, in these cases is never like the rough grating which is felt when a fracture is examined. The direction of the longitudinal axis of the arm is changed ; for the lower extremity of the humerus being placed outwards from the side, its longitudinal axis, if prolonged upwards, instead of passing towards the glenoid cavity, may be observed to be directed inwards towards the axilla. In this accident, numbness of the fingers is sometimes complained of, arising from the pressure of the head of the","page":606},{"file":"p0607.txt","language":"en","ocr_en":"607\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nbone upon some of the nerves of the brachial plexus.\nAnatomical characters of the dislocation into the axilla. \u2014 Sir Astley Cooper informs us that he dissected two recent cases of this dislocation :\u2014\u201cFirst case : A sailor fell from the yard-arm on the ship\u2019s deck, injured his skull, and dislocated the arm into the axilla. He was brought into St. Thomas\u2019s Hospital in a dying state, and expired immediately after. On the next day the shoulder joint was minutely examined, and the following were the appearances found :\u2014On removing the integuments, a quantity of extravasated blood presented itself in the cellular membrane, lying immediately under the skin, and in that which covers the axillary plexus of nerves, as well as in the interstices of the muscles, extending as far as the cervix of the humerus, below the insertion of the subscapularis muscle. The axillary artery and plexus of nerves were thrown out of their course by the dislocated head of the bone, which was pushed backwards upon the subscapularis muscle. The deltoid muscle was sunken, with the head of the bone. The supra-and infra-spinati were stretched over the.' glenoid cavity and inferior costa of the scapula. The teres major and minor had undergone but little change of position ; but the latter, near its insertion, was surrounded by extravasated blood. The coraco-brachialis was uninjured. In a space between the axillary plexus and coraco-brachialis, the dislocated head of the bone, covered by its smooth articular cartilage and by a thin layer of cellular membrane, appeared. The capsular ligament was torn on the whole length of the inner side of the glenoid cavity, and would have admitted a much larger body than the head of the os humeri through the opening. The tendon of the subscapularis muscle which covers the ligament, was also extensively torn. The opening of the ligament, through which the tendon of the long head of the biceps passed, was rendered larger by laceration, but the tendon itself was not torn. The head of the os humeri was thrown on the inferior costa of the scapula, between it and the ribs, and the axis of its new situation was about an inch and a half beloiv the centre of the glenoid cavity from which it had been thrown. The second casef adds Sir Astley Cooper, \u201c which I had an opportunity of examining, was one in which the dislocation had existed five weeks, and in which very violent attempts had been made to reduce the dislocated bone, but without success. The subject of the accident was a woman, fifty years of age. All the appearances were distinctly marked ; the deltoid muscle being flattened, and the acromion pointed; the head of the bone could also be distinctly felt in the axilla. The skin had been abraded during the attempts at reduction, and the woman apparently died from the violence used in the extension. Upon exposing the muscles, the pectoralis major was found to have been slightly lacerated, and blood was effused amongst its fibres; the latissimus dorsi and teres major were not\ninjured ; the supra-spinatus was lacerated in several places ; the infra-spinatus and teres minor were torn, but not to the same extent as the former muscle ; some of the fibres of the deltoid muscle, and a few of those of the coraco-brachialis, had been torn, but none of the muscles had suffered so much injury as the supra-spinatus. The biceps was not injured. Having ascertained the injury which the muscles had sustained in the extension, and, in some degree, the resistance which they opposed to it, I proceeded to examine the joint. The capsular ligament had given way in the axilla, between the teres minor and subscapularis muscles; the tendon of the subscapularis was torn through at its insertion into the lesser tubercle of the os humeri, and the head of the bone rested upon the axillary plexus of nerves and the artery. Having determined these points by dissection, I next,\u201d says Sir Astley Cooper, \u201c endeavoured to reduce the bone, but finding the resistance too great to be overcome by my own efforts, I became very anxious to ascertain its origin. I therefore divided one muscle after another, cutting through the coraco-brachialis, teres major and minor, and infra-spinatus muscles. Yet still the opposition to my efforts remained, and with but little apparent change. I then conceived that the deltoid must be the chief cause of my failure, and, by elevating the arm, I relaxed this muscle ; but still could not reduce the dislocation. I next divided the deltoid muscle, and then found the supra-spinatus muscle my great opponent, until 1 drew the arm directly upwards, when the head of the bone glided into the glenoid cavity. The deltoid and supra-spinatus muscles are those which most powerfully resist reduction in this accident.\u201d This dissection explains the reason why the arm is sometimes easily reduced, soon after the dislocation, by raising it suddenly above the horizontal line, and placing the fingers under the head of the bone, so as to lift it towards the glenoid cavity, which will sometimes prove effectual, because, in this position, the muscles are relaxed, so as no longer to offer any resistance to reduction. Sir Philip Crampton has adduced an example of dislocation of the shoulder joint, which illustrates in a satisfactory manner the anatomy of a recent case of dislocation into the axilla.\nCase.\u2014\u201c In the year 1808, a labouring man was brought into the County of Dublin Infirmary in a dying state: the persons who carried him stated that he had been engaged in digging under the foundation of a house that had been burned ; that a part of a partition wall fell upon him, and that they had found him buried under the rubbish : the man did not survive more than two hours. On examining the body eighteen hours after death, it was observed, that in addition to the injury of the head, which had proved fatal, the right humerus was dislocated into the axilla. To this part I directed the whole of my attention. I made a careful dissection of the joint, previously to reducing the dislocation, and was so fortunate as to obtain a drawing of the","page":607},{"file":"p0608.txt","language":"en","ocr_en":"608\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nparts, executed upon the spot, by a distinguished artist. On removing the integuments of the axilla, the cellular membrane, which was extensively ecchymosed, formed a kind of cap, closely embracing the head of the os humeri, which, when the axilla was cleared, was seen lodged on the inferior costa of the scapula, or rather, on its neck ; the head of the bone, in escaping from its socket, had pushed the teres minor downwards, and burst through the lower part of the subscapularis muscle, some of the fibres of which closely embraced the neck of the bone, while the bulk of the us-cle was pushed upwards, and detached from the inner surface of the scapula {fig. 434.).\nFig. 434.\nAxillary dislocation ; recent case. (After Sir P.\nCrampton.)\nThe neck of the humerus, therefore, was in some degree embraced by the divided fibres of the subscapularis muscle, while a portion of its head rested on the neck and part of the venter of the scapula, without the intervention of any muscular substance. The short head of the biceps, and the coraco-brachialis, were forced to describe a curve outwards, over the neck of the humerus on the sternal side, while the long head of the triceps crossed the neck of the bone obliquely on the dorsal side ; this strangulation of the head of the bone, bj' the surrounding muscles, was made most apparent when extension was applied to the fore-arm. The biceps and triceps seemed then to close behind the head of the bone, and interpose themselves between it and the glenoid cavity ; the tendon of the long head of the biceps remained in its groove, but the sheath in which it runs was partially ripped up. The capsular ligament was completely torn from the lower part of the neck of the humerus, to the extent of more than half its circumference, the torn edge appearing like a crest over the head of the bone. The great nerves and blood vessels of the arm were forced to describe a curve backwards, by the pressure of the head of the bone, which\nwas in contact with them. But the greatest injury had been sustained by the \u2018 articular muscles,\u2019 as they have been called, which lie on the back of the scapula. The tendons of the supra-spinatus, the infra-spinatus, and the teres minor, were completely torn off from the humerus, carrying with them, however, a scale of bone, which was ascertained to be the surface of the greater tubercle into which they are inserted.\u201d\nIn order to ascertain the nature of the obstacles which oppose the reduction of the dislocated humerus, the scapula was fixed, and the arm being raised to nearly a right angle with the body, extension was slowly applied to the arm by pulling at the wrist; it then appeared that so long as the hand was held supine, the head of the bone remained immovable; the chief resistance appearing to be caused by the closing of the biceps and triceps behind the head of the bone. The muscles of the back of the scapula being detached from the greater tubercle, could of course afford no resistance ; but, on turning the hand into the prone position, and giving a motion of rotation inwards to the whole limb, the extension being still maintained, the head of the bone glided easily into its socket. The appearances observed in this case are nearly identical with those which are described by Mr. Henry Thompson, in the Medical Observations and Inquiries, while they differ materially from those which were found by Sir Astley Cooper ; establishing an important fact, which, indeed, might have been inferred \u00e0 priori, that in apparently similar dislocations of the humerus, there may be very different hinds as well as degrees of lesion, and consequently very different causes of resistance to reduction. \u201c In Mr. Thompson\u2019s case,\u201d Sir P. Crampton adds, \u201c as in mine, the head of the bone was found lodged on the inside of the neck of the scapula, between the subscapularis and teres major muscles ; but during the eighteen days which had elapsed since the injury had been received, the cellular substance of the axilla had formed a kind of capsular ligament, which embraced the head of the bone, and contained a small quantity of mucus resembling synovia. In Mr. Thompson\u2019s case, the capsular ligament was completely torn from the whole circumference of the humerus. In mine it was detached to the extent of more than half the circumference. In both cases, the attachments of the tendons of the supra- and infra-spinatus muscles were torn off with the part of the bone they were inserted into ; in both cases, some fibres of the subscapularis muscle embraced the neck of the bone.\u201d In Sir Astley Cooper\u2019s cases, on the contrary, although the tendon of the subscapularis was torn through, the supra- and infra-spinatus muscles retained the connection with the greater tubercle, and \u201c until this muscle was relaxed, by raising the arm, the humerus could not be reduced by any efforts which he (Sir Astley) could make.\u201d In cases of dislocation of the humerus into the axilla, which have been left long unreduced,","page":608},{"file":"p0609.txt","language":"en","ocr_en":"609\nABNORMAL CONDITIONS\nthe head of the bone is found altered in its form, the surface towards the scapula being flattened, a complete capsular ligament en-\nFig. 435.\nAxillary dislocation ; case of long standing.\nvirons the head of the os humeri. The glenoid cavity is filled entirely by ligamentary matter, in which are to be found small portions of bone. These must be of new formation, as no portion of the scapula or humerus is broken. A new cavity is formed for the head of the os humeri on the inferior costa of the scapula, but this is shallow, like that from which the os humeri had escaped.\n2. Dislocation forwards. \u2014 This species of dislocation is much more distinctly marked than the former. The acromion is more pointed, and the hollow below it, from the depression of the deltoid, is more considerable. The head of the os humeri can be felt through the skin and pectoral muscle, and its convexity seen, in thin persons, just below the clavicle ; and when the arm is rotated, the protuberance may be observed also to rotate and accompany the motions of the arm. The coracoid process of the scapula is placed above and on the outside of the head of the bone, which we know is covered by the pectoris major muscle. The elbow is thrown out more from the side, and further back than it is in the case of dislocation into the axilla ( fig. 436.).\nMuch difference of opinion seems to prevail as to whether the arm is lengthened or shortened, as the result of this dislocation of the head of the humerus forwards. Mal-gaigne and Dupuytren both assert that the arm on the dislocated side is longer than natural; Sir A. Cooper expresses himself in opposite terms ; he says, that in the dislocation forwards and inwards of the head of the humerus, the arm is shortened. In our experience we have never found in the living subject the arm shortened ; and in the specimen from which fig. 436. has been taken, the centre of the new glenoid cavity is several lines below the centre of the original cavity, and the arm therefore must have been by, so much, longer than natural. The direction of\nVOL. IV.\n>F THE SHOULDER JOINT.\nthe longitudinal axis of the limb passing from below upwards, is much altered, being thrown\nFig. 436.\nDislocation of the head of the humerus forwards and inwards.\ninwards towards the middle of the clavicle. The pain attending this accident is less than it is in the case where the head of the bone is thrown into the axilla, because the nerves of the axillary plexus are less compressed ; but the motions of the joint are much more materially affected. The strongest diagnostic marks of the dislocation are these. The elbow is separated from the side and thrown backwards, and the head of the humerus can be felt to move below the clavicle when the arm is rotated. Sir Philip Crampton has adduced the following example of the ordinary dislocation forwards, in which the head of the bone was thrown at once on the neck of the scapula, without previously passing into the axilla.\n\u201c James Wilson, \u00e6t. 30, fell into a limekiln, in the immediate neighbourhood of the Meath Hospital, while the lime was still burning ; he was drawn up by ropes, but just as he reached the top of the shaft, the rope broke, and he again fell to the bottom, a distance of about fifteen feet, on the ignited stones. It appeared, on examination, made in the Meath Hospital, that in addition to several extensive burns and lacerations, there was a dislocation of the humerus, under the pectoral muscle. Mr. Macnamara, without assistance, reduced the dislocation, by merely drawing the arm gently forwards and downwards with one hand, while he pushed the head of the bone towards the glenoid cavity with the other. The man died in the course of the day, from the conjoint effects of the burn and the fall. Eighteen hours after death the\nR R","page":609},{"file":"p0610.txt","language":"en","ocr_en":"610\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nshoulder joint was dissected, by Mr. Macna-mara, from whom I take the description of the appearances, with the advantage of having the preparation before me while I write.\nThe dislocation was unattended with rupture of any muscle, or the separation of any tendon from its insertion into the bone ; by a slight effort the dislocation was reproduced, and the pectoral muscles being removed, the polished head of the bone was now seen lodged on the cervix of the scapula, at the root of the coracoid process, but extending nearly as far as the notch in the superior margin of the scapula. The head of the bone had passed out through a rent in the capsular ligament, over the upper edge of the tendon of the subscapularis, detaching this muscle from its connection, which is at this point but slight, with the inner surface of the scapula, and pushing its fibres downwards, so that they formed a curve, which partly embraced the neck of the humerus (flg. 437.). The supra- and infra-spinatus muscles were on the stretch, but had suffered no injury. The cellular substance covering their tendons was deeply ecchymosed, so as to mark their course most distinctly. On replacing the head of the bone, the opening in the capsular ligament through which it\nFig. 437.\nDislocation forwards and inwards. ( Sir P. Cramp-ton's case.)\nhad escaped from its socket, could be distinctly seen. It was formed, by a separation of the ligament from the interior side of the brim of the glenoid cavity from top to bottom, it was bounded at the top by the tendon of the supra-spinatus, and at the bottom by the inferior edge of the tendon of the subscapularis ; the rent was continued as far as the root of the lesser tubercle of the os humeri, and was of sufficient extent, hut no more, to permit the head of the bone to pass easily through it. The inferior part of the capsular ligament, however, the part corresponding to the axilla, was perfect. The great blood vessels\nand nerves lay to the sternal side of the head of the humerus, and were forced a little out of their course. The axis of the head of the bone in its disturbed position was scarcely a quarter of an inch higher than the axis of the glenoid cavity.\nSir P. Crampton observes, \u201c the anatomy of the recent case of dislocation forwards settles the long disputed question as to whether or not the humerus can be dislocated primitively in any other direction than downwards, or into the axilla ; it is plain, that in the case of Wilson, the head of the bone was thrown at once forwards, into the situation into which it appears under the clavicle ; as the inferior portion of the capsular ligament was not ruptured, and the attachment of the subscapularis and teres minor muscles to the inferior costa of the scapula remained undisturbed.\u201d\nMr. Key has given the following account of the appearances observed in dissection of the right shoulder joint of a patient who had had for seven years an unreduced dislocation of the head of the humerus, in the direction forwards and inwards. The specimen is preserved in the museum attached to St. Thomas\u2019s Hospital. The head of the bone was thrown on the neck and part of the venter of the scapulae, near the edge of the glenoid cavity, and immediately under the notch of the superior costa : nothing intervened between the head of the humerus and the scapula, the subscapularis muscle being partly raised from its attachment to the venter. The head was situated on the inner side of the coracoid process, and immediately under the edge of the clavicle, without having the slightest connection with the ribs; indeed, this must have been prevented by the situation of the subscapularis and serratus magnus muscles between the thorax and humerus. The tendons of all the muscles attached to the tubercles of the humerus were perfect, and are shown in the specimen preserved. The tendon of the biceps was not torn, and it adhered to the capsular ligament. The glenoid cavity was completely filled up by ligamentous structure, still however preserving its general form and character ; the tendons of the supra- and infra-spinati and teres minor muscles adhered by means of bands to the ligamentous structure occupying the glenoid cavity, and, to prevent the effects of friction between the tendons and the glenoid cavity in the motions of the arm, a sesamoid bone had been formed in the substance of the tendons ; the newly formed socket reached from the edge of the glenoid cavity to about one-third across the venter ; a complete lip was formed around the new cavity, and the surface was irregularly covered with cartilage. The head of the bone had undergone considerable change of form, the cartilages being in many places absorbed, and a complete new capsular ligament had been formed.\u201d\nThe accompanying wood-cut (fg. 438.) is taken from a scapula preserved in the museum of the College of Surgeons in Dublin, and re-","page":610},{"file":"p0611.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t611\nsembl\u00e9s much the specimen alluded to by Mr. Key. The newly formed socket reached from\nFig. 438.\nDislocation forwards and downwards. (Original, from the museum of the College of Surgeons, Dublin.)\nthe edge of the glenoid cavity, to about one-third across the subscapular fossa ; a deep cup was formed for the reception of the dislocated head of the humerus; the inner margin of this cup was fully half an inch above the level of the subscapular fossa; the glenoid cavity had lost all cartilaginous investment ; it was rough on its surface from bony deposition, and its inner margin was elevated somewhat into a sharp ridge, so as to form part of the margin of the new articular cavity for the head of the humerus.\n3. Dis/ocatiofi backwards of the head of the humerus on the dorsum of the scapula, the result of accident. \u2014 In this dislocation the arm is\nFig. 439.\nDislocation on the dorsum of the scapula.\ndirected from above downwards, inwards, and forwards. The deformity of the joint is well seen by viewing it in front, where a deficiency\nis noted of the normal roundness of the articulation. When we look at the shoulder sideways, the head of the humerus maybe seen to form a remarkable saliency behind the posterior angle of the acromion. In this dislocation the head of the bone is thrown on the posterior surface of the scapula immediately below the spine of this bone, and there forms a very remarkable protuberance, and when the elbow is rotated as far as practicable this protuberance moves also. The dislocated head of the bone may be easily grasped between the fingers, and distinctly felt resting below the spine of the scapula ; the motions of the arm are impaired, but not to the same extent as in the other luxations of the shoulder, and the longitudinal axis of the humerus may be observed to run upwards, backwards, and to a point, evidently behind the situation of the glenoid cavity. In Guy\u2019s Hospital Reports * Sir A. Cooper has published a case of this species of dislocation, from which we abstract the following.\nCase. \u2014 \u201c Mr. Key has given me the particulars of the following case. Mr. Complin was 52 years of age, and had been the subject of epileptic fits; one of them, which was particularly severe, occurred one morning while he was in bed, and in his violent convulsive smugglings his shoulder became dislocated on the dorsum of the scapula, presenting the ordinary symptoms of this accident in which dislocation had never been reduced.\u201d The circumstance most peculiar in this case was, that the head of the bone could by extension be drawn into its natural situation in the glenoid cavity ; but so soon as the force ceased to be applied it slipped back again in the dorsum of the scapula, and all the appearances of dislocation were renewed. The second peculiarity consisted in a sensation of crepitus as the bone escaped from its socket, so as to lead to a belief that the edge of the glenoid cavity had been broken off. The patient was unable to use or even to move the arm to any extent, nor could he by his own efforts elevate it from his side, and although he lived seven years after the occurrence of the epileptic fit, he never recovered the use of the limb. Mr. Key sent the following note of the dissection of the dislocated shoulder in this case to Sir A. Cooper ;\u2014\u201cThe dislocation of Mr. Complin\u2019s shoulder arose from muscular action alone in a paroxysm of epilepsy, and during his life it was thought probable that a portion of the glenoid cavity had been broken off, or a piece of the head of the os humeri, or perhaps the smaller tubercle, and that either of these injuries would account for the head of the bone not remaining in its natural cavity when reduced. But the inspection, post-mortem, proved that the cause of this symptom was the laceration of the tendon of the subscapularis muscle, which was found to adhere to the edge of the glenoid cavity, and was much thickened and altered in its character from its laceration, and from its very\n* Astley Cooper on Dislocations, &c., page 384., edition 1842, by Mr. B. Cooper.\nE R 2","page":611},{"file":"p0612.txt","language":"en","ocr_en":"612\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nimperfect and irregular union. The muscles of the dorsum scapulae were diminished, by being thrown out of use, and the tendon of the long head of the biceps muscle was entire, but glued down by adhesion.\u201d Upon further examination of the scapula and os humeri, Sir A. Cooper found the muscles and the situation of the bones to be as follows: \u2014 \u201c The head of the os humeri was placed behind the glenoid cavity of the scapula, and rested upon the posterior edge of that articular surface, and upon the inferior costa of the scapula, where it joins the articulation. When the scapula was viewed anteriorly, the head of the os humeri was placed in a line behind the acromion but below it, and a wide space intervened between the dislocated head of the bone and the coracoid process, in which the fingers sunk deeply towards the glenoid cavity of the scapula. When viewed posteriorly, the head of the os humeri was found to occupy the space between the inferior costa and spine of the scapula, which is usually covered by the infraspinatus and teres minor muscles. The tendon of the subscapularis muscle, and the internal portion of the capsular ligament, had been torn at the insertion of that muscle; but the greater part of the posterior portion of the capsular ligament remained, and had been thrust back with the head of the bone, the back part of which it enveloped. The supra-spinatus muscle was put upon the stretch, the subscapularis was diminished by want of action, and the infra-spinatus, and teres minor muscles were shortened and relaxed, as the head of the bone carried their insertions backwards. The tendon of the long head of the biceps muscle was carried back with the head of the bone, and elongated; but it was not torn. As to the changes in the bones, the head of the os humeri, and the outer edge of the glenoid cavity of the scapula, were in direct contact, the one bone rubbing upon the other when the head of the os humeri was moved ; and this accounted for the sensation of crepitus at the early period of the dislocation, as there was no fracture. The glenoid cavity was slightly absorbed at its posterior edge, so as to Torrn a cup, in which the head of the bone was received, and this latter bone and the articular cartilage had been in some degree absorbed where it was in direct contact with the scapula, as well as changed by attrition during the seven years the patient lived.\u201d The surface of the original glenoid cavity, instead of being smooth and cartilaginous, was rough and irregular, having elevations at some parts, and depressions at others. The extremity of the acromion was sawn off, to look for any little fragment of bone which might have been broken off, but not the smallest fracture could be perceived.\nMr. Key, in his account of another case of dislocation of the os humeri backward on the dorsum of the scapula, writes as follows : \u2014\n\u201c I found a very stout man sitting up in bed in great pain, and complaining more than patients commonly do under dislocation, and I concluded it to be some fracture about the\ncervix, especially as at first view nothing could be seen of a hollow under the deltoid muscle, the joint appearing round as usual. On passing to the man\u2019s side to examine the limb, the deformity of the shoulder became visible, the forepart appeared flattened, and the back of the joint fuller than natural : the head of the bone could be seen as well as felt, resting on the posterior part of the cervix scapulae. The elbow could be brought to the side, or raised on a level, with the acromion. Rotation outwards was entirely impeded, in consequence of the subscapularis being stretched, all motions of the limb giving him extreme pain, which was referred to the lower part of the deltoid muscle, in the direction of the articular nerves, which were probably injured by the pressure of the head of the bone.\u201d\nThe dislocation of the head of the humerus backwards on the dorsum of the scapula is said to be very easily recognised, yet the writer has seen two examples of it which had been overlooked at the moment of the accident, and he has heard of two others. When the swelling, the result of the laceration of parts, has subsided, the nature of the injury becomes very evident indeed. A gentleman, Mr. A. F., aged about 35 years, called upon the writer four years ago to examine his shoulder. He stated that he was thrown off a jaunting car about three months previously, and injured his shoulder, and that ever since he had had but very imperfect use of his arm. The patient had been educated as a medical man, had practised surgery, but did not himself suspect the nature of the injury, when,\nFig. 440.\nCase of Mr. A. F.\u2014 Dislocation of the head of the humerus backwards on the dorsum of the scapula.\nabout ten weeks after the accident, he called upon the writer. The nature of the injury","page":612},{"file":"p0613.txt","language":"en","ocr_en":"613\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nwas very manifest. The arm was placed close to the side, was neither lengthened nor shortened; he had no pain in the shoulder joint, but had very imperfect use of the limb. The shoulder had not the flat appearance externally surmounted by the prominent angle formed by the acromion, which characterises the axillary dislocation ; nor had he the fulness beneath the clavicle and in front of the acromion w'hich are noticed in the dislocation forwards ; on the contrary, a deficiency was observed in front beneath the acromion ; and here the fingers could be sunk into a deep fossa, which seemed to extend even to the unoccupied glenoid cavity ; while behind the posterior angle of the acromion a tumor as large as an orange could be seen and felt (fig. 440.). This rounded prominence moved with the shaft of the humerus ; a well-marked vertical groove showed the distinction between the convexity which belonged to the head of the dislocated humerus behind and that which formed the posterior angle of the acromion (fig. 440.).\nAn energetic attempt was made at the Richmond Hospital to reduce the dislocation in this case three months after the accident had occurred, but without success.\nDiagnosis between fractures of the superior extremity of the humerus and dislocations of the shoulder-joint.\u2014As we have already pointed out the symptoms which are peculiar to each of the forms of scapulo-humeral dislocations, we may here direct attention to the fact, that these symptoms are very similar to those which belong to fracture of the upper extremity of the humerus : so that in many cases the difficulty of distinguishing between these different injuries is such as to lead not uncommonly to a false diagnosis. Every person labouring under either a fracture or luxation of the superior extremity of the humerus, informs us that he has fallen on that side of the body on which the injury exists ; but the position of the arm at the moment of the accident will be found to have been different in the case of fracture and dislocation : so that if we know how the limb was placed at the moment of the fall, we may be led to conjecture from this alone the nature of the accident which has occurred. If, for example, when the patient is falling, his arm is separated from his body directed forwards, or outwards, as it were instinctively to break the fall, and save the upper part of the body, if under these circumstances displacement of the upper part of the humerus occurs, the existing deformity will be found to be the result of dislocation ; but if, on the contrary, the fall takes place when the arm is by the side, as, for instance, in the breeches pocket, and no effort is made by the patient, at the moment of the fall, to raise the arm, the momentum and weight of the body have been received on the point of the shoulder, the resulting injury has been most probably a fracture of the head and upper part of the humerus. In both cases the pain experienced at the shoulder is severe, and gives\nrise to the impression, on the patient\u2019s mind, that he fell on that part ; but if the patient has met with a dislocation, it will be found that in reality he has fallen on the palm of the hand, evidences of which the surgeon will be better able to discover in the excoriations which the palm has suffered, than by any report which the patient himself may be enabled to make. When the patient has met with a fracture, we shall, on inquiry, discover that the fall has taken place on the outside of the shoulder ; there is, in this case, no abrasion of the palm of the hand, while considerable tumefaction and extensive ecchy-mosis, the effects of contusion, are observable along the outer side of the arm. When called to the patient immediately after the accident, we notice those circumstances as to the hand and clothes which will instruct us as to the probability, whether the patient had fallen forwards on the palm of the hand, or completely outwards on the stump of the shoulder. In case of fracture, moreover, there is extensive ecchymosis ; in simple dislocation, little, if any ; but if it should exist, it is rather on the anterior and internal part of the limb, than on the outside, as in fracture. In both fracture and luxation the acromion is salient, and the deltoid flattened ; but as the displacement is more complete in luxation than in fracture, the prominence of the acromion and the depression beneath it are more marked in the former than in the case of fracture. When there is a luxation, and we wish to impart movements to the limb, the humerus often moves in connection with the scapula, as if the two bones made but one body. If there is a fracture, there is abnormal mobility at one point in the upper part of the humerus. This mobility is ordinarily accompanied by a crepitus which is best elicited by seizing the inferior extremity of the humerus at the elbow and rotating it on its long axis.\nFinally, great efforts are frequently necessary to effect a reduction of the dislocated humerus ; but once replaced, the bone remains in its proper articular cavity, and the deformity of the shoulder does not recur ; but in fracture, although the bone may be replaced with comparative facility, yet, if it be left unsupported, the deformity will almost immediately recur. In the case in which it is not easy to distinguish a fracture from a luxation, Dupuytren gives the precept \u2014 \u201c Rendez au membre, par des man\u0153uvres convenables, sa forme et sa longueur naturelles ; retournez aupr\u00e8s du malade sept ou huit heures apr\u00e8s : si vous trouvez l\u2019\u00e9paule d\u00e9form\u00e9e, soyez assur\u00e9 que vous avez \u00e0 faire \u00e0 une fracture.\u201d * Malgaigne has made the observation, that in all luxations of the head of the humerus, the head of the bone must descend below its ordinary level, and consequently that, no matter which of the three dislocations has occurred, the dislocated arm must be longer than the other. This appears to us\n* Le\u00e7ons Orales.\nR R 3","page":613},{"file":"p0614.txt","language":"en","ocr_en":":6-14\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nto be a point, by attention to which we may be assisted in our endeavours to establish the diagnostic marks between dislocation and fracture, because, in fracture of the humerus, we have almost invariably found, whether from some overlapping of the bones, or impaction of one of the fragments into the other, that some shortening of the arm exists. If there be dislocation, the arm is sometimes abnormally lengthened, and never shortened. In the measurement of the injured limb we have therefore a simple means to resort to, -which will no doubt assist us much in making -our diagnosis.\n4. We have heretofore adverted only to the ordinary symptoms and anatomical characters belonging to the three dislocations which the head of the humerus is liable to ; but practical surgeons have, however, noticed that a dislocation of the head of the humerus is sometimes combined with a fracture of this bone. In this case the fracture \u2018may sometimes engage merely the tuberosities, sometimes the anatomical, and sometimes the surgical neck of this bone. It has been long ago noticed .by Thompson *, that when the head of the humerus is dislocated into the axilla, the greater tuberosity of this bone, which gives attachment to the three posterior capsular muscles, is torn off from the shaft of the humerus, and left attached to these muscles. This observation of Thompson has since been repeated by others, from amongst whom we have already quoted a case adduced by Sir Philip Crampton, of an axillary dislocation, in the dissection of which it was found that the tuberosities were detached. Such a complication with a dislocation of the humerus would no doubt facilitate the reduction of the dislocated bone, but its subsequent maintenance in its place would be thereby rendered very difficult.\nWe have reason to believe that a fracture, completely detaching the greater tuberosity of the humerus, may be combined with a dislocation forwards; and in this case, although the dislocation may be reduced, the head of the humerus cannot be maintained in the glenoid cavity. We have for some time considered this to be the explanation of the specimen contained in the Richmond Hospital Museum, an account of which we find given by Dr. R. Smith, and from which we abstract the following:\u2014\u201c Upon removing the soft parts, the head of the bone presented itself, lying partly beneath, and partly internal to the coracoid process. The greater tuberosity, together with a very small portion of the -outer part of the head of the bone, had been completely separated from the shaft of the .humerus. This portion of the bone occupied the glenoid cavity, the head of the humerus having been drawn inwards, so as to \u2022project upon the inner side of the coracoid process ; it was still contained within the capsular ligament, which was thickened and enlarged, and bone had been deposited in its\ntissue. A new and shallow socket had been formed upon the costal surface of the neck of the scapula, below the root of the coracoid process, and the inner edge of the glenoid cavity, the tuberosity was united to the shaft only by ligament. The injury had occurred many years before the death of the patient, but the history of the case was not precisely known.\u201d\nBut fracture of the greater tuberosity may also occur, as a consequence of falls on the outer side of the shoulder, or otherwise, without any dislocation following.\nFracture of the lesser tuberosity of the humerus may, we suppose, be an accident likely to attend on dislocations of the head of this bone, and would, we imagine, be attended with consequences similar to those which followed the laceration of the tendon of the subscapularis muscle in a case of dislocation on the dorsum of the scapula, noticed by Sir A. Cooper and Mr. Key.\nDislocation of the head of the humerus, accompanied with, a fracture of the neck of the humerus. \u2014 Sometimes the luxation of the humerus is complicated with a fracture of the anatomical or surgical neck of this bone ; we have then one of those rare lesions to deal with, for which nature and art can do but little. In such a case it is plain that the dislocation has first occurred. When there is both a dislocation and fracture, Sir A. Cooper says, the symptoms resemble those which usually accompany the dislocation into the axilla, the head of the bone being there felt ; but there is somewhat less of the hollow to be observed below the acromion, and the deltoid muscle does not seem much depressed, because the broken extremity of the shaft quits the head and lodges in the glenoid cavity of the scapula. Upon rotating the arm, the broken shaft of the bone can be perceived to move under the acromion ; there is but little power of motion ; and considerable pain is felt not only in the shoulder, but in the arm and hand. The head of the os humeri can be felt when the arm is raised, and the surgeon\u2019s fingers are introduced into the axilla ; but when the arm is rotated at the elbow, the head of the bone remains entirely unmoved, or very little obedient to the motions of the elbow. In some cases, but not always, a distinct crepitus can be perceived.\nThe broken end of the os humeri is drawn somewhat forwards, but is easily pushed into the glenoid cavity, from which, unless it be supported, it is again drawn by the pecto-ralis and coraco-brachialis muscles.\nThe arm, measured from the acromion to the elbow, is shorter than the other.*\nAs this accident is produced by great violence, the parts are much obscured by the effusion of blood, and by the inflammation which speedily follows ; but, for the first three hours, the muscles are so lax, that but for the pain it occasions, considerable motions of the limb might be produced.\nMedical Obs. and Enq. yol. ii. p. 349.\nSmith on Fractures.","page":614},{"file":"p0615.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t615\nIn one case detailed by Sir A. Cooper, the tubercles were broken off with the head of the bone, and the fractured extremity of the neck of the os humeri was placed in the glenoid cavity of the scapula. In another case, the fi\u2019acture was intra-capsular, and the head of the bone was at the same time dislocated forwards, under the pectoral muscle, and placed at the inner side of the coracoid process.\nDelpech* gives the history of a case of fracture of the anatomical neck of the humerus, combined with a dislocation. The case was remarkable, and differed from all the others recorded, in being an example of that rare form of dislocation, where the bone is thrown on the dorsum of the scapula. The history of the case is accompanied with an engraving.\nWith regard to the case of dislocation into the axilla, complicated with fracture, Sir A. Cooper says, \u201c 1 would observe that in this case the fall and depression of the shoulder is less striking than in the case of simple axillary dislocation, as the shaft of the bone fills up the glenoid cavity ; also, that in the case complicated with fracture, the head of the bone can still be distinctly felt in the axilla, and that as it does not move when the os humeri is rotated from the elbow, this becomes the principal diagnostic mark.\n\u201c That a grating sensation can generally be felt, and sometimes a very distinct crepitus, especially if the elbow be raised outwards during the rotation of the arm.\n\u201c That the upper extremity of the shaft of the humerus can be felt advancing to the coracoid process ; but that it is easily returned into the glenoid cavity, and that it there rotates with the arm, but easily again slips forward.\n\u201c That the accident which produces it is much more severe than that by which simple dislocation into the axilla is produced ; and there is, therefore, more contusion, more swelling, and more pain.\u201d\nMuscles.\u2014If in some cases the tuberosities of the humerus are broken off and remain connected with the muscles when the head of the humerus is dislocated, in others, we may be prepared to expect that in the dissection of cases of dislocation, the capsular and other muscles will be found lacerated. Tf, as has been stated, the supra-spinatus be the muscle which is most put on the stretch when the head of the humerus is dislocated downwards, we need not be surprised to learn that this muscle is very frequently found to have been ruptured, or to have torn away a fragment of bone from the head of the humerus.\nIn the dislocation on the dorsum of the scapula, the dissection of which is detailed in Sir A. Cooper\u2019s work, we find the following observations made by Mr. Key, with reference to a very peculiar phenomenon noticed in that case : namely, \u201c that, during the patient\u2019s life-time it was thought probable that a portion\n* Clinique Chirurgicale, Paris, tom. i. p._234.\nof the glenoid cavity had been broken off, or a piece of the head of the os humeri, or perhaps the smaller tubercle ; and that any of these injuries would account for the head of the bone not remaining in its natural cavity when reduced ; but the inspection postmortem proved that the cause of this symptom was the laceration of the tendon of the sub-scapularis muscle, which was found to adhere to the edge of the glenoid cavity, and much thickened and altered in its character from its laceration, and very imperfect and irregular union.\u201d\nThe tendon of the long head of the biceps is sometimes altered, as to its direction, in cases of complete dislocation, and adhesions between it and the contiguous parts occur ; but there are very few cases recorded, or to be found in museums, which prove that in true dislocation from accident, the tendon was found ruptured. In this respect, the effects of accident and disease on this tendon are strongly contrasted ; for, as the result of disease, the tendon, so far as its articular portion is concerned, is very generally removed altogether.\nBesides lesions affecting the bones, muscles, and tendons, injuries of other tissues may be found occasionally to accompany or succeed to dislocations of the shoulder.\nA dislocation of the head of the humerus may be accompanied with an \u0153dematous swelling of the arm and forearm ; with a paralysis of the dislocated extremity, or with a laceration of the axillary artery, and a diffused aneurism ; it is said also that occasionally an emphysematous swelling of the shoulder has followed the reduction of the dislocation ; and on other occasions, that the articular structures have been attacked with very severe inflammation. For example, as to this last : Mr. Hunter gives an account of a case of dislocation of the shoulder-joint, which he dissected three weeks after its reduction, from which, if we could be influenced by one case, we might infer that inflammation, though latent, may sometimes be the consequence of a dislocation of the head of the humerus. Mr. Hunter\u2019s observation is as follows: \u201cWhat was very remarkable, and what I did not expect, there was a good deal of p\u00fcs in the joint.\" *\nPartial or general paralysis of the muscles of the arm has also been observed as a consequence of a dislocation of the head of the humerus, particularly when either the circumflex nerve alone, which is that most usually injured, or all the nerves of the brachial plexus have been violently contused, or greatly stretched ; or even torn 'across either at the time of the accident, or by the violence of the means used to restore the luxated humerus, when the dislocation has been left long unreduced. Flaubert, of Rouen, speaks of an emphysema of the chest succeeding his efforts to reduce an old luxation of the humerus ;\n* Pathological Catalogue of Museum of R. C. Surgeons, England, vol, ii. p. 20. No. 868.\nR R 1","page":615},{"file":"p0616.txt","language":"en","ocr_en":"616\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nand it is known that Desault had already observed a similar occurrence. A Memoir, containing six cases published in the Repertoire d\u2019Anatomie et de Chirurgie, by M. Flaubert, surgeon in chief to the H\u00f4tel Dieu de Rouen, is not well calculated to encourage practitioners to attempt the reduction of old dislocations. In five of these cases the reduction was followed by serious accidents. M. Flaubert observes, that in many cases when paralysis of the upper extremity had been attributed to the dislocation itself, he believes it was rather owing to the violent efforts made for its reduction ; laceration of muscles and extensive abrasion of the skin have been noticed as the consequence of these efforts, and even death from diffuse inflammation has occurred ; but these accidents, whether the result of dislocation, or of the means used to restore the bone to its place, must be considered as rare in this country, as from the comments of Mr. Mar, and the observations of the Editors of the Le\u00e7ons Orales of Dupuytren, they seem to have been in Paris. The latter observes, \u201c Le hasard qui a fourni \u00e0 M. Flaubert, dans le court espace de trois ou quatre ans, un ensemble de tous les acci-dens les plus graves qui puissent d\u00e9terminer la r\u00e9duction, est vraiment extraordinaire : il faut sans doute en chercher la cause dans des circonstances particuli\u00e8res, qui sont inconnues.\u201d *\nAlterations of the nerves.\u2014We have noticed as belonging to the symptoms of dislocation of the head of the humerus, that the patient complains of pain extending down the course of the nerves of the arm and the forearm, and also of numbness. These symptoms generally disappear when the dislocation is reduced, but sometimes they persist. The pressure which the nerves of the axillary plexus undergo has naturally been referred to as the cause of these unpleasant symptoms. The nerves, besides being stretched, have been sometimes even torn across; when this has oc-cured the effects produced must long remain ; such cases are very rare. Among all the nerves in the vicinity of the shoulder-joint which have been referred to as the seat of injury the result of luxation of the humerus, the circumflex nerve, which supplies the deltoid, is that which has been found most frequently injured. Indeed, from the manner it winds round the neck of the humerus to arrive at its destination at the under surface of the deltoid muscle, it can scarcely escape being stretched and elongated, and such a lesion of this nerve we may well expect to be followed by a paralysed condition of the deltoid muscle. The circumflex nerve has been found compressed by the dislocated head of the humerus, flattened, and firmly adherent to the capsule of the joint. We find in the Museum of Bartholomew\u2019s Hospital, (Catalogue, p. 124, vol. i., No. 42.,) a preparation of a shoulder-joint, exhibiting a dislocation of the humerus, which occurred eighteen months before death. \u201c The\n* Le\u00e7ons Orales, vol. iii. page 140.\nhead of the humerus rests on the anterior surface, near the inferior border of the scapula. The tendons of all the capsular muscles were entire ; the long tendon of the biceps retains its attachment to the glenoid cavity. The circumflex nerve is compressed by the head of the dislocated bone, and was in consequence flattened, and firmly adherent to the capsule of the joint. The dislocation had been followed by permanent paralysis of the deltoid muscle.\u201d\nArtery. \u2014 Luxations of the head of the humerus havebeen found complicated with alesion of the axillary artery. This we believe to be a very rare occurrence. M. Flaubert of Rouen cites cases of this lesion to have occurred in the H\u00f4tel-Dieu de Rouen, as a consequence of the efforts made by surgery to reduce old luxations of the humerus. In the following case, which the writer thinks of sufficient importance to be here introduced, the laceration of the axillary artery was recognised a few minutes after the dislocation had occurred \u2014 and before any effort whatever had been made to restore the humerus to its place.\nCase. \u2014John Smith, \u00e6t. 50, was thrown down by a runaway horse one morning during the summer of 1833; in about ten minutes after this occurred, he was brought to Jervis Street Hospital, when the writer, at that time one of the surgeons of the institution, was prescribing for the extern patients. The man was in a cold perspiration, pallid, and apparently on the verge of syncope. The writer immediately observed that the patient had a dislocation of his left humerus, into the axilla, and, proceeding to point out, as was his custom, to the clinical class the diagnostic marks of the luxation, he noticed that the cavity of the axilla was filled up to a remarkable degree. This sudden filling up of the axilla he immediately concluded could be attributed to no other source than to the laceration of a large artery. He quickly sought for the pulse in the radial and brachial artery of the dislocated limb ; but no pulsation could be felt in any artery below the site of the left subclavian, while the pulse, though feeble, could be readily felt at the heart, and in every external artery of the system, except in those of the dislocated arm.* The writer then observed to the clinical class, that' in this case there were two lesions to be noticed, namely, a dislocation into the axilla, the features of which were very well marked, complicated with a rupture of the axillary artery ; in a word, besides the dislocation there was a diffused aneurism ; the latter was unattended by any pulsat\u2019on, so that he conjectured the artery was completely torn across. He did not long deliberate as to what course was the best to pursue under existing circumstances, because he felt sure that, so far as the torn artery was concerned, if the head of the humerus was once, restored to its place, this vessel would be in at least as favourable a condition\n* Mr. Brassington, now a practising surgeon at Port Rouines, was one of those present on this occasion.","page":616},{"file":"p0617.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t617\nas it then was, and secondly that the state of prostration and debility (he patient was in, at that moment, offered an opportunity which, if once lost, might not again be afforded, of reducing easily the dislocation. Taking the patient, therefore, unawares, the writer placed his knee in the axilla of the dislocated arm, and then slight extension having been made over this fulcrum, the bone at the first trial returned into the glenoid cavity. The parent was placed in bed in the hospital, under the care of the late Mr. Wallace, whose day it was for admitting accidents. There was much more superficial ecchymosis about the axillary, and subclavian region, and along the inside of the left arm, than is usually observed after a simple dislocation of the head of the humerus. The deep axillary swelling remained stationary for some days; but no pulsation could be discovered either in it, or in the arteries of the limb. A feeble and frequent pulse could be felt in the left subclavian, and in all the other arteries, as well as in the heart. After the space of ten days, Mr. Wallace\u2019s month of attendance having expired, the case came under the care of Mr. O\u2019Reilly, who having been satisfied that a diffused aneurism existed, and was on the increase, performed the operation, at which the writer was present, of tying the subclavian artery in the third stage of its course. The patient recovered, and was discharged from the hospital about two months afterwards ; he lost the last two fingers by gangrene ; but whether from an attack of erysipelas, which succeeded the operation, or from the effects of the ligature of the main artery of the limb, is not clearly known. The man lived for many years afterwards, in the immediate vicinity of the Richmond Hospital.\nSection 3.\u2014Congenital malformation of the shoulder joint. \u2014 Although little can be done by medicine or surgery to alleviate, much less to remedy, the evils attending on congenital malformation of the shoulder joint, still it appears to us to be not the less necessary that the abnormal conditions of this articulation resulting from congenital defects should be studied. These, like some other congenital malformations of the joints, attract but little notice during the first months of infancy, but as the child grows the defect becomes more manifest. It very commonly happens in these cases, that after some time the ordinary surgical opinions taken on the case, and the measures recommended failing, as they naturally do, to produce satisfactory results, the ill-fated patient, born with malformation of the shoulder joint, is subjected to ignorant and empirical treatment, the inutility of which too often proves to be the least of the evils attending it.#\n* About ten years ago the writer met in consultation, surgeon W. Wilde on the case of an only child, a girl of thirteen years of age, who had a congenital malformation of the shoulder joint,presen ting exactly the appearance of the joint (fig. 441.). The young lady is now twenty-three years of age, and the writer has been informed by one of her relatives,\nThe most common form of congenital malformation of the parts composing the region of the shoulder joint that we have noticed, has been apparently the result of an arrest of development, and of atrophy affecting the muscles, the bones, and probably also the nerves of this region. Sometimes we find both shoulder joints are malformed in the same individual ; generally one only is thus affected. In this last case the atrophied condition of the malformed joint is well seen on comparing the normal and abnormal shoulder: the latter is smaller than the former ; the muscles around the joint are so imperfectly developed, that the coracoid and the acromion processes and the head of the humerus become unusually conspicuous. The deltoid and articular muscles are so weak, and the capsule so loose, that the limb seems usually to be drawn down, as it were, by its own weight, and then becomes displaced forwards and inwards beneath the coracoid process, where it habitually remains, the head of the humerus forming a protuberance in front, which yields to the slightest force pressing it backwards towards the usual site of the glenoid cavity of the scapula. When the arm is taken hold of at its lowest extremity, as at the elbow, and drawn backwards, the head of the humerus advances forwards and passes beneath the coracoid process, and a depression, corresponding to the posterior half of the glenoid cavity, is perceptible. On the contrary, when the elbow is drawn forwards, the head of the humerus recedes towards the normal site of the glenoid cavity ; when the humerus is raised up perpendicularly towards the acromion, and the influence of the weight of the limb is thus counteracted, the shoulder appears of its natural form, but diminished about half the normal size. The muscles around the joint are so badly developed, that the bony process which surrounds it becomes very conspicuous.\nThe accompanying drawing is designed to pourtray the general aspect of one of these cases of congenital malformation of the shoulder joint in the displacement inwards of the head of the humerus (fig. 441.).\nCase. \u2014 The following is the history of the case from which the drawing has been taken. M. H., \u00e6t. 28, is in every respect healthy and well formed, except as to his left shoulder, which, since his birth, has always been noticed to have been smaller than the other. This defect gives a peculiar appearance to his whole figure as he stands or walks. As his arm hangs by his side, the longitudinal axis of it is directed downwards and a little backwards. The head of the humerus is a little advanced as well as depressed beneath the outer margin of the coracoid process ; it is\nthat she is in no respect better as to the condition of her shoulder joint ; but that her general health has suffered materially in consequence of the various treatment she had been subjected to in vain. Her parents, ignorant of the nature of the case, and too sanguine in their hopes, had been the easy dupes of charlatanism.","page":617},{"file":"p0618.txt","language":"en","ocr_en":"618\nABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nalso slightly adducted towards the middle the head of the humerus passes backwards line. When the shoulder is viewed posteriorly beneath the acromion, and a depression can a depression corresponding to the situation be felt in front beneath the coracoid process, of the posterior half of the glenoid cavity is corresponding to the portion of the abnormal observable : into this depression the finger can articular cavity which the head of the humerus be sunk so far as to reach the surface of the had just before occupied. The muscles of the posterior part of the glenoid cavity. When region of the shoulder are very imperfectly the arm is drawn forwards across the chest, developed, but those of the fore-arm and\nFig. 441.\nCase of M. H. \u2014 Congenital malformation of the left shoulder joint, with luxation of the head of the\nhumerus inwards.\nhand seem of their normal size. The patient has but little power of moving the affected upper extremity. The trapezius muscle of this side is well formed, therefore he can by means of its influence elevate on the side of the trunk the whole limb. The deltoid and capsular muscles are very imperfectly formed, and consequently the patient has no power of abduction, nor of rotation, of the humerus. The shoulder has not the usual rounded form, but still it does not present the flattened appearance, nor the acromion the angular outline which characterises the accidental luxation of this joint. Yet the acromion process does project somewhat, and when the arm hangs by the side, the head of the humerus, distinct and prominent, is removed so much from the under surface of the acromion, as it were by the weight of the limb, that the thumb can be easily placed between them. When we take hold of the elbow and raise\nthe arm vertically, the joint assumes more of a natural form. Still, independent of its comparative diminution of size, it wants the rotundity and fulness of contour ordinarily derived from a proper development of muscular covering. The elbow joint is perfect as to its form and functions. This patient has been under the writer\u2019s observation for many years, and these symptoms have not varied.\nAnatomical characters of congenital malformation of the shoulder joint with displacement of the head of the humerus inwards. \u2014 We may consider the following as a good example, showing the anatomical characters of the congenital malformation of the shoulder joint, with displacement inwards of the head of the humerus ; the congenital defect existed in both shoulder joints.\nCase.\u2014\u201c A female, \u00e6tat 28, who had been for many years a patient in the lunatic department of the House of Industry, died of chronic in-","page":618},{"file":"p0619.txt","language":"en","ocr_en":"ABNORMAL CONDITIONS OF THE SHOULDER JOINT.\t619\nflammation of the membranes of the brain, and Dr. Smith* made the post-mortem examination. Upon entering the room his attention was attracted by the appearances which the shoulder joints presented. The deviations from the normal state were most remarkable at the left side. The muscles of the shoulder and arm were atrophied, the acromion process projected considerably, and the head of the humerus could be perceived lying a little beneath the coracoid process, the apex of which was in a line with the bicipital groove of the humerus. The natural roundness of the shoulder did not exist, and the elbow could be readily brought into contact with the side. The right shoulder joint presented similar appearances, but in a slighter degree; the head of the humerus was not placed so directly beneath the coracoid process ; but the flattened form of the shoulder, the atrophied muscles, and the projection of the acromion, all indicated that the condition of the joint was nearly similar on both sides. From the last circumstance, and the absence of any external sign of disease, it was concluded that the deformities were the result of an original or congenital malformation.\nThe anatomical examination of the joints confirmed this opinion. Upon the left side there existed scarcely any trace of an articular surface in the situation which the glenoid cavity occupies in the normal state ; but there had been formed on the costal surface of the scapula a socket of a glenoid shape, measuring an inch and half in its vertical direction, and an inch and a quarter transversely. It reached upwards to the under surface of the coracoid process, from which the head of the humerus was merely separated by the capsular ligament, there being no interval between the summit of the abnormal socket and the coracoid process. Around this socket the glenoid ligament, perfect in every respect, was continued from the margin of that small portion of the natural articulating surface which existed upon the axillary margin of the bone, and to the apex of which the tendon of the biceps was attached. The capsular ligament was perfect. The head of the humerus did not present its natural spherical form ; it was of an oval shape, its long axis corresponding with that of the long axis of the shaft of the bone. The shaft of the humerus was small and seemingly atrophied, and the position of the bone with respect to the coracoid and acromion processes varied according as the motion of rotation inwards or outwards was imparted to the arm. During rotation outwards in this case the head of the bone passed towards the acromion process, and occupied the small portion that existed of the glenoid cavity on the normal site; while rotation inwards brought the head of the humerus altogether beneath the coracoid process, so that the finger could be easily sunk into the outer portion of the socket.f\n* Smith on Fractures, &c.\nf This species of locomotion of the articular head\nOn the right side, although the condition of the bones was somewhat different, the characteristic features of the deformity were similar.\nIn this case it was ascertained, that there never had been any disease of either of the shoulder joints at any period of the patient\u2019s life, nor had they ever been the subject of injury or accident of any description. The position of the glenoid cavity in this case, beneath the coracoid process, the remarkable form of the head of the humerus, the presence of a perfect glenoid ligament, the absence of any trace of disease, and the existence of the deformity upon each side, all indicate that the nature of the malformation must have been congenital, although but little of the early history of the case was known.\nCongenital malformation of the shoulder joint, with displacement of the head of the humerus on the dorsum of the scapula. \u2014 The second case we think right to abstract from Dr. R. Smith\u2019s work is also a very important one, equally proving that a double congenital luxation of the head of the humerus may be observed to take place backwards on the dorsum of the scapula, just as we have already shown that\nFig. 442.\nCongenital luxation on the dorsum of the scapula.\nan analogous dislocation forwards has occurred.\nof a bone representing the proper rotation which should exist, is a consequence of the existing lax state of the fibrous structures of the joint. We have already noticed a similar condition of the ligaments, and a similar effect, when describing a case of congenital malformation of the radio-humeral joint. See Elbow Joint, Yol. II. note to page 81, where it is said \u2014 \u201c These movements did not consist in a simple rotation of the radius on its longitudinal axis, but a real change of the upper extremity of the radius on the outer condyle of the humerus.","page":619},{"file":"p0620.txt","language":"en","ocr_en":"620\tABNORMAL CONDITIONS OF THE SHOULDER JOINT.\nCase. \u2014 A woman, named Judith Doyle, died upon the 8th of February, 1839 : she had been a patient for fifteen years in the lunatic department of the House of Industry ; was subject to severe epileptic convulsions, which were the cause of her death. While making the examination of the brain, the unusual appearance which the left shoulder joint presented accidentally attracted the author\u2019s attention. The head of the humerus appeared to have been dislocated on the dorsum of the scapula. Finding that the opposite shoulder presented precisely similar appearances, he had no hesitation in expressing his opinion that the case was one of double congenital luxation of the head of the humerus backwards.\nThe two shoulders resembled each other so perfectly, not only in their external conformation, but likewise in their anatomical characters, that the description of one will be sufficient.\nThe coracoid process, owing to the removal of the head of the humerus from its vicinity, formed a most remarkable projection, and the subject being emaciated, the coraco-brachialis\nFig. 443.\nCongenital malformation of the left humerus.\nand the short head of the biceps could be seen passing very obliquely downwards and outwards, and the anterior margin of the coraco-acromial ligament stood out in strong relief. The acromion process was unusually prominent, although it did not project as much as in any of the accidental dislocations of the shoulder. The glenoid cavity could not be felt, although the head of the humerus was so far removed from its natural position. The shoulder appeared higher than natural, and was flattened anteriorly ; but posteriorly a round, solid tumour plainly indicated the situation of the head of the bone placed on the dorsal surface of the scapula, immediately below the spine and posterior angle of the acromion. The head of the bone thus displaced could be seen and felt to accompany all the movements given to the shaft of the humerus. The transverse diameter of the\nshoulder was much greater than natural, the distance between the coracoid process and the external surface of the head of the humerus being three inches and a half; the arm was directed obliquely downwards and inwards ; the elbow was in contact with the side, and the hand and fore-arm in a state of pronation. Upon removing the muscles and exposing the interior of the joint, I found that there was no trace of a glenoid cavity in the natural situation ; but upon the posterior surface of the neck of the scapula there was a well-formed socket, which received the head of the humerus. It was an inch and three quarters in length, and one inch in breadth ; it was a little broader above than below, and its summit was less than a quarter of an inch from the under surface of the acromion process. It was directed outwards and forwards, was covered with cartilage, and surrounded by a perfect glenoid ligament. The tendon of the biceps muscle arose from the most internal part of its superior extremity, from whence it passed downwards and outwards very obliquely, in order to reach the bicipital groove of the humerus.\nThe axillary margin of the scapula, if prolonged upwards, would have passed nearly altogether internal to the abnormal socket. The surfaces of the acromion process had not their normal aspects, but looked directly upwards and downwards, being on the same continuous plane with the surfaces of the spine of the scapula that contribute to form supra- and infra-spinatus fossa ; a circumstance in itself sufficiently showing that the malformation was congenital, and not altogether limited to the shoulder joint itself. The capsular ligament was perfect; the scapula was smaller than natural, and its muscles badly developed. The head of the humerus was of an oval form on the right side, somewhat broader above than below; its anterior half was in contact with the glenoid cavity : this portion was covered with cartilage, the remaining half being rough and scabrous, and destitute of articular cartilage. The greater tubercle was normal as to form, but the lesser was elongated for the extent of one inch, and curved upwards, forming a concavity on its upper surface to receive the tendon of the biceps ; on the left side, the head of the humerus presented almost similar appearances. The hypertrophy of the lesser tuberosity, Mr. Smith observes, appears to have been the result of a process established to counteract the danger to which the very oblique course of the tendon, with regard to the muscular fibres, exposed it.\nThe history of this case, so far as the motions which the head of the humerus was capable of performing, is not known ; but we may conclude from the post-mortem examination, that there was here a complete congenital dislocation on the dorsum of the scapula. A well-formed socket existed on the dorsum of the scapula, upon which the head of the humerus was permanently lodged ; it did not shift its position during the motions of","page":620},{"file":"p0621.txt","language":"en","ocr_en":"SIXTH PAIR\nrotation, as was mentioned to be the case in the former example.\nWe must agree with the author that the phenomena noticed in this rare and remarkable case originated neither in disease, nor were they the result of accident. The complete absence of a glenoid cavity in the normal situation for it, the existence of the malformation on both sides, the perfect resemblance to each other of the abnormal sockets, in form, size, and position, the integrity of the tendon of the biceps and of the capsular and glenoid ligaments, and the peculiar form of the head of the humerus, as well as of the acromion process of the scapula on each side, all support the opinion that the malformation was intra-uterine and congenital.\n(Robert Adams.)\nSIXTH PAIR OF NERVES. Le Sixi\u00e8me Nerf, Fr. ; Sechster Nerv, Germ. According to the enumeration of Willis, this name is bestowed upon a single soft round cord, which is, with the exception of the fourth, the smallest of the cranial nerves, and which, passing forwards from the medulla oblongata to the external rectus of the eye, finds its distribution in this muscle.\nThe anatomy of this nerve is readily subdivided into three portions. The first of these extends from its apparent origin to the point where it enters the cavernous sinus ; the second includes its course in that cavity ; and the third, commencing at the sphenoidal fissure or foramen lacerum anticus, contains the course of the nerve in the orbit, and is terminated by its distribution.\nThe visible origin of the nerve is by one or two bundles from the medulla oblongata, from the anterior pyramid of which it appears at its upper part, or in the transverse depression immediately behind the posterior border of the pons varolii. By careful dissection, the nerve can be traced into the substance of this anterior column, and, apparently, it passes through it towards the grey matter which more deeply surrounds this tract of the medulla. Further than this it is impossible to follow it satisfactorily, although some anatomists have, with Mayo, assigned to it a yet deeper origin. In the first part of its course the nerve passes forwards, upwards, and outwards for a very short distance, from near the median line to the posterior extremity of the cavernous sinus which forms the commencement of the inferior petrosal sinus. In this course it lies upon the concave basilar surface of the sphenoid bone, and is covered above by the projecting pons varolii ; and at the front, where it leaves the interior of the skull, the arachnoid membrane is reflected around it. It next passes through an opening in the dura mater, and enters the cavity of the sinus. This aperture is situated just internal to the tip of the petrous bone, and is about one-third of an inch anterior to the orifice of the fifth nerve, bnt on a rather lower level.\nOF NERVES.\t621\nOn entering the sinus, it is somewhat curved or bent into a more horizontal direction, and crosses over the posterior or vertical part of the carotid artery, which here experiences its sigmoid bend by the side of the body of the sphenoid bone. It next lies parallel to, but beneath, the horizontal part of this vessel, and passes almost directly forwards, through and amongst the numerous reticulations which occupy the cavity of the sinus, but it is covered by its lining membrane. At the anterior extremity of the cavernous sinus it enters the orbit by passing between the two heads or processes of origin of the external rectus muscle.\nSince the nerve in this course lies within the sinus, it is internal to the three nerves, viz. the third, fourth, and the ophthalmic division of the fifth, which are situated in the dura mater forming its outer wall. Posteriorly, the lowest of these, or the ophthalmic nerve, lies on much the same level, but nearer to the sphenoidal fissure. The latter nerve having passed upwards, the sixth is left again occupying the most inferior and internal position of all the nerves which pass through this orifice, the lower division of the third being to its inner side, and somewhat superior to it, whilst above this is the nasal branch of the fifth. Below the sixth nerve, the ophthalmic vein perforates the dura mater of the sinus by a separate aperture,\nIn the cavernous sinus, the following branches are connected with, or come from, this nerve : \u2014\n1.\tIt is connected with the sympathetic nerve by several filaments. Two of these are of considerable size, and may be traced backwards at rather an acute angle from the trunk of the nerve, to join those numerous ramifications of the sympathetic which constitute the carotid plexus surrounding the artery in this venous cavity.\n2.\tAn anastomosis, or junction with the ophthalmic branch of the fifth, is described by most anatomists, and may be readily verified in the recent subject. One or more branches, having very much the same direction and appearance with the preceding to the sympathetic, pass backwards from the sixth nerve, in the anterior part of the sinus ; leaving it at a very acute angle, inclining outwards as they go, and finally, entering the wall of the sinus to join the ophthalmic branch, not far from the Gasserian ganglion. These branches also exist in the sheep, and some other of the lower animals.*\n* A very similar description might be extended to the analogous junction of the fourth nerve with this division of the fifth. Thus, in the sheep, three or even four considerable branches leave the ophthalmic nerve at an acute angle to join the fourth nerve. They effect this junction very obliquely, and may be traced forwards (distad ) for at least some distance. May not some of these filaments, traced backwards from the fourth nerve to the wall of the cavernous sinus, which they enter to join the ophthalmic division, have been the tentorial branches of Bidder, which he describes as coming from the former nerve to be distributed to the dura mater of the tentorium ?","page":621},{"file":"p0622.txt","language":"en","ocr_en":"622\nSKELETON.\n3. A very fine filament from the sixth nerve to the ciliary or lenticular ganglion has been described by several authors.\nSubsequently to the cavernous sinus, the course of the nerve is but short. Arriving at the posterior extremity, or apex of the orbit, the nerve lying to the outer side of that part of the third which supplies the inferior rectus and oblique muscles, runs slightly upwards, and turning outwards, continues for a very short distance along the inner surface of the external rectus. It finally breaks up into numerous minute filaments, which enter the ocular surface of this muscle to be distributed to it.\nPhysiology of the sixth nerve.\u2014The function of the nerve is, perhaps, sufficiently indicated by the preceding details. Since anatomy shows that its terminal distribution is exclusively to a muscular surface, we should on this ground alone be tolerably entitled to predicate its motor function.\nThe little that is known of its comparative anatomy confirms the inference. In all the higher vertebrata it is distributed to the external rectus. In some, however, it experiences an enlargement, and a further distribution. The muscle which sweeps the broad nictitating membrane over the bird\u2019s eye, and the funnel-shaped, or choanoid muscle which surrounds the optic nerve and eyeball of many mammalia, are both supplied from this nerve.\nSo also one or two cases are recorded, in which an injury of this nerve from disease in the neighbourhood has produced paralysis of the external rectus, and an inward squint. While, vice versa, the experiment of galvanising the nerve has been accompanied by violent contractions of the muscle, and an external strabismus.\nThe insensibility of the nerve is, perhaps, less certain than might at first appear, though Longet* distinctly states that pinching the nerve at its origin is unattended by signs of pain. The branch of junction with the ophthalmic nerve seems to be, from its direction and appearances, much more like a filament from the sensitive to the motor nerve, than from the latter to the former. If this be the case, they would seem to be somewhat analogous to the junction of the numerous branches of the fifth with the portio dura on the face. And in the absence of direct experiment upon the nerve beyond the seat of this union, one might conjecture it as possible, that the sixth nerve was possessed of a slight sensibility similar to that of this portion of the seventh. Concerning the import of the junction with the sympathetic, little can here be said ; for although, as compared with the size of the communicating nerves, this union is larger than most others, yet there does not seem any sufficient reason for supposing other differences.\nThe distribution of a branch from the sixth to the ciliary ganglion has been thought by Longet and others to explain the persistence\n* Sur le Syst\u00e8me Nerveux.\nof movements of the iris after paralysis of the third nerve. But besides that the constant existence of this filament seems hardly verified ; perhaps the interposition of a ganglion between the paralysed nerve and the ciliary filaments might alone be thought a sufficient explanation of the inconstancy or imperfection of the result, without requiring the existence of another and an uninjured channel as the cause.\nBibliography.\u2014See \u201c Nerve.\u201d\n( William Brvnton.')\nSKELETON. \u2014 The name skeleton, cye-\\erov, formed from o-yfXXw, to dry, is, in anatomy, ordinarily applied to denote that assemblage and arrangement of all the osseous pieces of an animal framework in such connection and relationary order as the hand of nature has disposed them for fitting operation in the living body.\nThe less the name skeleton impresses the mind with the configuration of any particular form of the osseous machines, the better is it fitted as an abstract general title, under which to give a comparative survey of all figures of the osseous system, whatever be their special characteristics; and this abstract survey being my present purpose, I find that the name skeleton, devoid as it is of any direct and inconvertible meaning, conveniently extends itself over all varieties of the osseous fabrics of the four higher classes of animals ; from the mutual comparison of which I shall strive to elicit the law which creates them in the character of a unity in variety *, a condition of form by which the many species gather themselves together naturally into a circle and point to some unknown oneness of character which enchains them the one to the other.\nThis law of unity in variety is still uninterpreted ; and though it formed the moving theme of the great Grecian naturalist j* three thousand years back, and afterwards lay in cold obstruction till resumed in later times by Leibnitz, Newton, Buffon, Cuvier, Geoffroy St. Hilaire, Oken, Goethe, Cams, OwenJ,\n* Leibnitz makes use of this phrase as being the general expression of his ideas of that condition of development manifested throughout the animal kingdom, namely the condition of an all-encompassing structural analogy which relates organised beings more or less closely to one another. His \u201c loi de continuit\u00e9 \u201d is founded likewise upon the same general fact. He defines the universe as \u201c l\u2019unit\u00e9 dans la vari\u00e9t\u00e9,\u201d and of the animal kingdom he writes, \u201c tout va par d\u00e9gr\u00e9s dans la nature, et rien par saut.\u201d See \u0152uvres Philosophiques de M. de Leibnits, liv. p. 440.\nt Aristotle, the great founder of generalisation in the physical sciences, was strongly impressed with the common resemblances or analogies of animals, and expresses the fact as follows : \u2014 \u201c But some animals neither have parts specifically the same, nor the same according to excess and defect, but according to analogy.\u201d History of Animals, book i. p. 4. trans. by! Taylor.\nJ The late work of the learned Hunterian professor, entitled \u201c Homologies of the Vertebrate Skeleton,\u201d contains, in addition to his own especial views, a complete account of all that has been written upon the subject of skeletal analogies by the leading com-","page":622},{"file":"p0623.txt","language":"en","ocr_en":"SKELETON.\nGrant, and others, still does it remain as an open arena of inquiry, courting the votary of truth to enter there and allure her from her secret covert. All that has been written has not fixed the Protean interpretation of this law which governs the developement of vertebrated skeletons. Since, therefore, this theme (upon which so many great inquirers have assayed interpretations which conflict with each other, and in the struggle lose the clue of truth), even to this hour fails of the culminating idea, and is by so much imperfect, of what avail would it be to the reader or myself were I to discuss the merits of the various opinions such as they stand? Rather than dispute about opinions, I shall turn to the facts themselves, upon which those opinions have been grounded, and engage at once in the comparison of facts as facts independent of all opinion respecting them, and unmindful of the names * by which they are liable to be mistaken for what they are not.\nUnder the abstract term skeleton, I shall take a general survey of the whole subject of comparative osteology ; and if the reader chooses to call this survey \u201c transcendental,\u201d I shall endeavour to show that it shall not be visionary. My argument shall set out from a first proposition, through a successional enchainment of propositions ; and in the matter of all the propositions taken collectively, I shall body forth an interpretation hitherto unknown in anatomical science. The facts and their proper interpretation may be fairly termed the body and soul of truth, and such a truth is a compound of the actual and the intellectual. The facts themselves give evidence to all observers of the truth of \u201c unity in variety,\u201d but it is by inductive reasoning that the intellect is to interpret the law, the potential agency, by which the same facts are at the same time uniform and yet various.\nThe object which I shall keep in view while constructing my comparisons, is to demonstrate the figure of unity, and give interpretation to the figures of variety which are sprung of it. To this end I shall prove,\u2014\n1st. That all the osseous skeletal forms are quantitatively unequal things.\nparative anatomists of the German and French schools. To this work, and the principle which the author endeavours to establish, I shall frequently refer ; and believing (as all who shall study that work must believe) that the meritorious object of its distinguished author is to give creation to a great truth in science, at the same time that he is not unwilling to give ear to all counter-argument rationally advanced, I shall therefore not hesitate to question the principle set forward in the work, as freely as shall serve my own purpose, which holds the like object in view. In whatever points, therefore, I may take objection to the author\u2019s reading, and in doing so may appear too rash to question so great and philosophical an authority, it is the cause which must be my excuse.\n* \u201c This, if we rightly consider and confine not our thoughts and abstract ideas to names, as if there were or could be no other sorts of things than what known names had already determined and, as it were, set out, we should think of things with greater freedom and less confusion than perhaps we do.\u201d Locke, Reality of Knowledge.\n623\n2d. That they are the unequal quantities of a greater or archetypal form * a unity which has undergone such an infinitely graduated metamorphosis of its parts as to yield these unequal skeletal forms.\n3d. That the law of formation is one of degradation of an archetypal uniform original.\n4th. That these unequal skeletal forms constitute the species or varieties of the unity of the archetype.\n5th. That the whole or archetypal form of which these unequal skeletal figures are the parts, is the only absolutely uniform skeletal series.\n6th. That nomenclature and all modes of classification, according to specific distinctnesses, have no real meaning apart from the consideration of this law of an archetypal uniform prime model undergoing a graduated metamorphosis of its parts. That in this higher law of graduated series is enveloped all lesser laws of classes, orders, genera, species, and individuals, which, whatever be the amount of their distinctive characters, do one and all point to a unity of type more or less.\nWith this purpose before the reader\u2019s mind, I proceed to lay down my propositions as preliminaries by which to pioneer a passage through the blinding thicket of nomenclature and gain the light beyond it, the light of a general law f in nature. But before he\n* This term, archetype, having been first introduced by me in the study of comparative osteology, may require here a word in explanation. When I first applied myself to the study of the law of \u201c unity in variety \u201d which presides over the development of vertebrated skeletons, there appeared to be such a shadowy and ill-defined meaning in the term unity in variety, and the facts of form themselves presented in such a mysterious condition of enchained analogous characters, and at the same time gave such unmistakeable evidences of an enchained specific diversity, the latter encountering the former condition at every step of inquiry, and neither the differences nor the analogies (while contemplated as such under the same regard) holding forth to me any promise of an end to labour and research, that I at length resolved to know (in addition to the self-evident analogy which the facts manifested) whether or not the deferential properties were mainly owing to some law which degraded or proportioned the lesser and special forms from some greater or whole form\u2014some integer or full skeletal figure which might be seen as containing in its own quantitative character the sum of all known varieties or species. The comparative method which I adopted to define the existence of such a figure realised my expectation, as I shall presently show, and to this figure I gave the name archetype.\nIn a paper \u201c On Anatomical Nomenclature,\u201d addressed to Professors Owen and Grant, published in a number of the Lancet, March, 14. 1846, I have spoken of the figure of an archetype skeleton.\nAbout the same time that I since published my work on \u201c Comparative Osteology and the Archetype Skeleton,\u201d bearing date 1847, I felt gratified to see that the learned Professor Owen sanctioned the name archetype, and gave it the weight and interest of his philosophical researches. See his work, entitled \u201c The Archetype and Homologies of the Vertebrate Skeleton,\u201d published 1848, being a second edition of his work bearing the same title, published 1847.\nf \u201c Les lois, dans la signification la plus \u00e9tendue, sont les rapports necessaires qui d\u00e9rivent de la","page":623},{"file":"p0624.txt","language":"en","ocr_en":"SKELETON.\n624\npasses with me to my task of comparison, I warn him that he should feel within himself a full conviction of the truth, that in order to gain a fair insight of the law of formation, he must not suffer names of different significations to hide the common analogy or similitude r which the things themselves manifest. He must have fully freed himself of the barbarisms of the nomenclature which the unreasoning human anatomist still makes use of ; he must not suppose that because one spinal piece is named sacrum, fit'is therefore absolutely different to another spinal piece named vertebra. And even in respect to the name vertebra*, which \u25a0 applies alike to all spinal segments, however quantitatively different these may be, he should not think these the same things in form and dimensions, and elemental constituents, simply because they bear the same name.\nFor in reality this name vertebra attaches to bodies which are quantitatively different, and is, therefore, a name as truly misapplied to generalise not only over the spinal units of the skeletal axes of the four classes of vertebrata, but even over those of the human type ; as if, while viewing a series of circles, semicircles, and segments, we called it a series of segments of semicircles or of circles, which it evidently is not. We would not call the two quantities, viz. circle and segment, by the same name ; neither should we name such different quantities as cervical, dorsal, and coccygeal forms under the common title \u201c vertebrae.\u201d If we fully ackowledge to this first truth, truth will be begotten of it ; but if we still begin the calculation with the error, error will spring from out of it, and defy all mathematical computation.\nProposition I. Vertebi\u00e6 are unequal quantities.\u2014In the human spinal axis I find that those bodies which the human anatomist terms vertebrae are not quantitatively similar, equal, or homologous.f The cervical vertebra (a,y%.\nnature des choses.\u201d Esprit des Lois, lib. i. ch. 1. Montesquieu.\n* Lamarck originated the name vertebrated, as characterising one great division of the animal kingdom,\u2014\u201c Les animaux vert\u00e8bres,\u201d from the other \u201cLes animaux sans vert\u00e8bres.\u201d But comparative osteology, as studied in the present time, has almost rendered this name obsolete, incapable, as it evidently is, to be the instrument wherewith to generalise the skeletal frameworks of the four classes of animals. Even the originator himself seems to have entertained a doubt as to the efficiency of the name, or any mode of classification, or method, or nomenclature used in subdividing the continuity of the chain of nature. He writes, \u201c Mais j\u2019ai d\u00e9j\u00e0 montr\u00e9 qu\u2019il est un produit de l\u2019art, et que malgr\u00e9 les apparences contraires il ne tient r\u00e9ellement rien de la nature.\u201d See Philosophie Zoologique, tom. i. chap. v.\nf This term \u201c homologous,\u201d as used by the geometrician, means corresponding. Figures are called similar or corresponding whose sides and angles are homologous. Quantities having the same manner or proportions are homologous. Quantities, therefore, which are not equal to one another are not homologous ; but such quantities, though being rnr-equal, may still possess the correspondence which we see apparent in the proportionals of a whole quantity ; thus a segment of a circle or a semicircle,\n414.) differs in this respect from the dorsal ver-teura (c) ; this from the lumbar vertebra (e);\nFig. 444.\n\nVertebrae of the human spine,\nShowing a quantitative difference. The similar parts of each bear the same figures.\nthis from the sacral vertebra (h); and this from the coccygeal vertebra (i). In all animal spinal axes I see that those bodies which the comparative anatomist names vertebrae are likewise quantitatively different. The several classes of vertebrae termed cervical, dorsal, lumbar, sacral, and caudal, are actually developed of unequal quantities. And it is, moreover, most true that even the vertebrae of any one class, whether of the cervical class, the dorsal, lumbar, sacral, or caudal, are not quantitatively similar or equal. In animal cervices, thoraces, or loins, the vertebrae constituting any of those regional divisions of the spinal axis are not equal quantities. Even in\nthough not equal to the circle, manifest a proportional correspondence all three; and in the same way, vertebral quantities which manifest to each other a similar degree of proportional correspondence, seem to point to some unknown whole quantity of which they are the parts. Philosophical anatomists seem to have all agreed upon the point, that the name vertebra attaches to certain osseous forms arranged along the spinal axis, which, in fact, are proportionally diverse bodies, and being so acknowledged, they have directed comparative research to determine the quantitative form of the \u201c typical vertebra.\u201d The difficulty of this inquiry into the form and quantitative character of the typical vertebra may be learned from the fact, that science has not, as yet, determined it upon the firm basis of demonstrative evidence.","page":624},{"file":"p0625.txt","language":"en","ocr_en":"SKELETON.\nthe human cervix, thorax, or loins, or sacrum, or caudex, the vertebrae of each region manifest those quantitative differences. For we find in the human neck that b, or in the loins f, occasionally develops a surplus rib (y%.444. b and f, 4); which circumstance gives rise to a serious objection to the rule, that \u201c the mammal cervix is constant to the number of seven vertebrae,\u201d or that the thorax of even the human skeleton develops twelve vertebrae constantly, or that the human lumbar region is confined to the number of five vertebras constantly. Jt is evident, therefore, that the bodies named vertebrae are quantitatively different bodies, as seen not only in all spinal axes comparatively estimated, but even in the one animal spine of human type.\nProp. II. Even the one vertebra is not of equal quantity in all individuals of the same species.\u2014 Comparative research proves that all vertebrae are quantitatively unequal entities ; but this is not all, for even when I fix attention upon the single isolated vertebral segment of the spine, I find that it manifests a fluctuating character as to proportions and elementary quantity. The seventh cervical vertebra (a, jig. 444.) of the mammal spinal axis occasionally produces a cost.d appendage (4 of b). The first lumbar vertcora (e,fig. 444.) of the human spine likewise develops now and then the costal appendages (4 of f, fig. 444.) ; and hence it is that anatomists are still undecided whether to name them thoracic vertebrae or not. I do not here intend to discuss those several interpretations which anatomists have advanced concerning the cervical and lumbar ribs, for we should find ourselves in the end as little enlightened about the true nature of the anatomical fact as when we first set out, suffice it here that we fully own to the fact; that the body which we name vertebra is not always equal to itself at all times even in the one fixed locality of the spinal series.\nProp. III. All vertebrae contain a greater or lesser amount of certain known elemental pieces. \u2014If we will consider why it is that we designate vertebral bodies under one generalising appellation, we will find that it is on account of vertebra; (whatever be their special variety) containing few or more of those elemental nuclei from which vertebrae are fashioned. Thus as we find vertebrae to be constituted from a whole sum of elementary pieces proper alone to vertebral form, we therefore consent to give the name vertebra to every spinal figure which shall produce any one element proper to the ideal vertebral type, But then we must not understand by this name vertebrated, a condition of absolute quantitative uniformity*\n* The uniformity of a serial line of bodies implies that all units of the line of serial order are quantitatively equal and homologous. A series of circles would constitute such an uniformity, because all such circles would be similar. Uniformity, taken in this sense of equality among the units of the series, does not characterise the vertebral spinal series ; but while we see that vertebrae, though not uniform as quantities, are still various only as proportionals of a greater ens or archetype, then the question arises as to how these propor-\nVOL. IV.\n625\nthroughout the bodies so named ; for to do so would be as directly opposed to natural evidence as to understand by the name endo-skeleton, that all figures so named were absolutely uniform with each other in quantity. The truth is that vertebrae are as much varied to each other as skeletons ; but the truth also is that vertebrae are only quantitatively different, just as skeletons are. A coccygeal vertebra (i,^g.444.) is only different from a lumbar (f,e) or cervical vertebra (a, b)' by quantity ; and a skeleton of a frog is different to that of a whale by the conditi\u00f6n of variable quantity also. But a coccygeal vertebra (i,fig. 444 ) is in reality a vertebral centrum (5) unattended with the presence of those other elementary pieces, such as laminae marked 2, 2, spinous (l),-and transverse processes (3), which elsewhere constitute the completer vertebral form ; and hence it is to be inferred that a coccygeal vertebra is a minus quantity, and as such differs in this respect only from a lumbar or cervical vertebra ; these latter being plus in those very same elements which the coccygeal vertebra wants. It is sufficient for us at present to know clearly that all vertebrae have some elements in common, and that the only difference which appears between them is occurring by a simple omission of elementary parts from some vertebrae, which parts are present and persistent in other vertebrae. The coccygeal bone (i, fig. 444,), being as a vertebral centrum (5) identical with the centra marked 5 in all other vertebra, is different from all other vertebrae simply by the loss ot parts ; and those parts which it has lost are evidently such parts as I find in a vertebra elsewhere posited, viz. the parts marked 1, 2, 3, 4.\nProp. IV. The dorsal vertebra of human anatomy is an artificial figure. \u2014 The human anatomist separates the dorsal vertebra (c, fig. 444.) from its costal appendages marked 4 in d, fig. 444., and by so doing he disconnects forms which nature has created inseparable from each other. In nature there is no such ens as the dorsal vertebra (c, fig. 444.) developed without the ribs (4 of d.) ; nor can we conceive the idea of a dorsal ver-\ntionals have had creation ? It is evident that the solution of this question is attainable only by a rule of equation, which, while it acknowledges the condition of the proportional, or the a\u2014b, must fill up or supply mentally (without deference to the doctrine of functional fitness) the differential quantity which is to equate it with a-\\-b ; and this is the mode which I adopt, in order to re-establish the original typical uniformity of skeleton bodies, for I shall prove that the known quantitative difference between two unequal forms renders them equal in idea. The typical skeleton of Carus and Owen is an ideal creation, sprung from a rule of comparison which rejects (as I mean to do) the teleological doctrine of Cuvier, and undertakes to compare form as form, regardless of the difference as to function. The paramount necessity of this will at once occur to the reader, and he will recognise in the truly philosophical researches of the Hunterian professor an advance towards the truthful interpretation of the law of formation, equal in degree to the measure of this mode of comparison adopted by him.\ns S","page":625},{"file":"p0626.txt","language":"en","ocr_en":"626\tSKELETON.\ntebra naturally independent of its costa.* When we bisect the circles we make semicircles ; but by so doing we cannot possibly lose sight of the fact, that both semicircles once constituted the whole circle ; and in the same way, when we separate the dorsal vertebra (c) from its attendant ribs (4 in d), we cannot obliterate from the memory the idea, that the dorsal vertebra and its ribs once formed an entire osseous quantity as that represented by d, having the ribs appended. When the human anatomist separates the dorsal quantity (c, fig. 444.) from the costal elements 4 in d, and describes the quantity of c as a vertebral figure, he commits an error no less visibly opposed to natural evidence than if he separated one half of the dorsal element from the other half, and called either half a vertebra. The dorsal vertebra (c) of human anatomy is therefore inseparable from its thoracic ribs (4 of d), and to these several pieces naturally combined and collectively contemplated (in d), I give the name costo-vertebral quantity.\nProp. V. The cervical vertebra develops the costal appendages also.\u2014In order to prove incontestably that the anterior moiety (4) of the\nFig. 445.\nA, dorsal vertebra ; b, cervical.\ntransverse process (4,3,y%.445. b), is the true homologue of the thoracic rib (4<fig. 445. a), I\n* I call the reader\u2019s attention particularly to this fact, as a starting point from which I set out with my argument, which is to conduct to the recognition of what I call whole quantities in the skeleton axis. It will be seen afterwards, that owing to this first error of the an thropotomist arbitrarily severing the ribs from the dorsal spinal centre, and giving to this latter the name vertebra, much confusion has arisen in the comparative method and its inferences. \u201c Errores radicales et in prima digestione mentis ab excel) enti\u00e2 functionum et remediorum sequentium non curantur.\u201d Novum Organon Sci-entiarum, Aph. 30.\nshall lay down my remarks as follow : \u2014 I separate from the human spinal axis that body (c,fig. 444.) which the human anatomist terms the \u201c dorsal vertebra ; \u201d and on comparing it with the cervical vertebra (a,^. 444.), I find that both figures are identical as to the number and position of their elemental pieces in all respects save one particular. This one point in which the cervical vertebra (a,fig. 444.) differs from the dorsal vertebra is evidently the anterior moiety (4) of the transverse process of the cervical vertebra (a) ; for the dorsal vertebra (c), such as the human anatomist describes it, does not contain any elemental piece as the true counterpart or homologue of the element (4) which is posited as the anterior half of the cervical transverse process.* In both vertebrae (a, c, fig. 444.), I find the spinous elements marked 1, the laminae or neural arches (2), and the bodies or centra (5) ; but it is attaching to the transverse processes of both vertebrae that a doubt arises as to their identity. Now if I call the posterior moiety (3) of the transverse process of fig. 445. b, the true homologue or counterpart of the dorsal transverse process {fig. 444. o, 3), I still have no element in the dorsal vertebra (fig. 444. c), wherewith to compare the anterior half (4) of the cervical transverse process of fig. 445. b. But when I apply the costal piece (4,fig. 445. a) to the dorsal vertebra, constituted of the pieces 1, 2, 3, 5, then it becomes evident that this costa is supplying the place of the anterior half (4) of the cervical transverse process ( fig. 445.).\n* All anatomists (the comparative as well as the human) had, until lately, overlooked the compound nature of the transverse process of the cervical vertebra ; and even when this character of the process came to be fully acknowledged, still so difficult was it for them to emancipate themselves from the toils of the original error committed by the anthro-potomist, that we find them more willing to bend the stubborn facts of nature in accordance with the error, than to correct the oversight. Thus, agreeably with the artificial vertebral quantity of the human anatomist\u2019s \u201c dorsal vertebra,\u201d whose transverse process is single, that of the cervical vertebra being double, both processes were held to correspond nevertheless ; and consequently, when such a fact as that of the anterior nucleus of the cervical transverse process being produced to the dimension of a cervical rib appeared, they, with Meckel, interpreted this as a prolongation of the cervical transverse process, which they had already regarded as homologous with the process so named in the dorsal vertebra: or with Blainville, they acknowledged its costal character and proportions, but interpreted it as belonging to a \u201c category of ribs proper to themselves,\u201d distinct from those of the thorax, and also diverse to those called \u201c cervical ribs \u201d in other classes of animals. And although it had been broadly asserted, long since, by Hunauld, Sandi-fort, and others, that the transcendental law gave to even the human skeleton more than twelve pairs of ribs\u2014the supernumerary ones which now and then stood upon the cervical and lumbar vertebrae\u2014 still, owing to the obstructiveness of the pre-con-ceived doctrine of the mammal cervix being accounted limited to the number of seven ribless vertebrae, even nature herself failed to prove the invalidity of that general rule, though she presented them with the sloth\u2019s cervix, which produces nine vertebrae, and that of the human species occasionally producing only five or six.","page":626},{"file":"p0627.txt","language":"en","ocr_en":"SKELETON.\t627\nAnd it cannot be doubted, for \u2019a moment, that both these elemental pieces, marked 4 in both figures, are identical ; for many facts go to prove it : first, both elements marked 4 are posited in the same situation with respect to the other pieces (3, 2, 1,5) of the vertebrae; second, both are \u201cautogenous that is to say, they are developed as separate and isolated deposits; third, they hold the same serial order in the spinal axis ; fourth, the anterior element (4) of the cervical transverse process (fig. 445. b), is that which is occasionally converted into a rib, as seen in b, fig. 444., and thereby simulating more closely the thoracic rib (4) of the dorsal vertebra (fig. 445. a.) ; fifth, a negative evidence may be adduced to prove that the anterior half (4) of the cervical transverse process of fig. 445. b, is the true counterpart of the thoracic rib (fig. 444. b, 4) ; for the more clearly it can be shown that the posterior half (3) of the cervical transverse process of fig. 445. b, is the homologue of the dorsal transverse process (fig. 444. c, 3), the more evident must it appear that neither one or the other of these last-named pieces are homologous to either of the two former ; sixth, the posterior half (3) of the cervical transverse process (fig. 445. b) and the dorsal transverse process (fig. 444. c, 3) are \u201cexogenous \u201d growths ; that is to say, they are produced of elemental nuclei common to them and the \u201c neural \u201d * or laminar arches marked 2 ; and therefore it appears that the cervical vertebra (fig. 445. b) possesses a costal element (4), just as the dorsal vertebra (j\u00a3g.445. a) does, the only difference between these vertebras being, that the costa of the latter is produced of greater dimensions than the costa of the former.\nProp. VI. All the cervical vertebr\u00e6 develop costal appendages. \u2014 The identity which has been proved to exist between the seventh cervical vertebra and the first thoracic costo-verte-bral quantity will allow it to be inferred, that all the cervical vertebr\u00e6,the atlas not excepted, which are fashioned of an equal number of elemental nuclei, must therefore be identical with all the thoracic costo-vertebral quantities. The only difference which exists between the cervical vertebrae, even that named atlas (fig. 446.), and the thoracic costo-ver-\nFig. 446.\ntebral quantities (fig. 444.) is one of quantity ; and this difference in quantity appears upon comparison to be alone attaching to the costal\n* This term, \u201c neural arch,\u201d is used by Professor Owen, from whom the term originates. \u201c By \u201c neural arch, I mean both neurapophysis and neural spine, or the totality of the distinct parts of which such arch is composed.\u201d Homologies of the Vertebrate Skeleton, p. 190.\nappendages marked 4. \u2014 The thoracic costae are of larger dimensions than the cervical cost\u00e6.\nProp. VII. The lumbar vertebra develops the costal appendage.\u2014When I take the dorsal vertebra (c,fig. 444.) (of human anatomy) separated from its costae, and hold it in comparison with the lumbar vertebra (e, fig. 444.), I find that the elemental nuclei of both are, for the most part, equal in number and similar in position and shape. The points by which anatomists doubt their absolute identity are the processes (3 of c and 4 of e), named \u201c transverse \u201d in both, and the process (3 of e) named \u201c tubercle \u201d in the lumbar form. The cause of this doubt I find to be occasioned by an error as to the identity of elementary nuclei, and a consequent misapplication of terms. The cause of the anatomical error originates with human anatomy having described as a complete dorsal vertebra that figure (c, fig. 444.) which has never been seen separate from its ribs, as it appears in d,fig. 444. The best mode, therefore, whereby we may correct this error, is to take nature as she presents to us, and interpret her by her own evidence, not through the artificial system of any human invention. While I compare the first lumbar vertebra (b,fig. 447.) with the last costo-vertebral tho-\nFig. 447.\nracic form (a, fig. 447.), I discover that nature has developed them of the same elemental pieces. In both the spinous element (1), the neural or laminar elements (2), and the bodies or centra (5), are apparent. In both are to be traced the true transverse processes which are homologous to each other in every respect, I mean the process named \u201c tubercle \u201d (3) of the lumbar vertebra (b), and the process named \u201c transverse \u201d (3) of the thoracic figure (a). Both these processes are identical in form, mode of growth, relative position in regard to the other vertebral elements (1,2, 4, 5), and in serial order with regard to each other. They are the true transverse processes by every anatomical proof, for they are produced of elemental pieces common to them","page":627},{"file":"p0628.txt","language":"en","ocr_en":"628\nSKELETON.\nand the neural arches (2).\u2014They are \u201c exogenous.\u201d Now the thoracic rib (4 of a) is also the true homologue of the lumbar misnamed and mistaken \u201c transverse\u201d process (4 of b), for both these structures are identical in every respect : 1st, they hold the same serial order ; 2d, they are posited in the same situation with respect to the other vertebral elements ; 3d, they are autogenous ; 4th, the so called \u201c transverse process \u201d (4) of the lumbar vertebra (b) is that very structure which occasionally presents to us in articular costal form and function as seen in 4 of F, fig. 444., thereby more closely becoming assimilated to the thoracic rib of the dorsal vertebra ; 5th, by negative evidence it may be shown that the thoracic rib (4 of a) is the true homologue of the so named transverse process (4) of the lumbar vertebra (b), for while it stands manifest that the \u201c tubercle \u201d (3) * of the latter is counterpart of the transverse process (3) of the dorsal vertebra, then it must follow that the thoracic rib and the lumbar \u201c transverse process \u201d f so called are also counterparts. The lumbar vertebra therefore produces the costal appendage.^\nProp. VIII. All the lumbar vertebral develop costal appendages. \u2014 That which is true of the first lumbar vertebra and the last costovertebral thoracic form must be true of the five lumbar vertebras and the twelve thoracic costovertebral forms, for all the lumbar vertebrae are fashioned of an equal number of elementary pieces. The difference which exists between lumbar vertebrae and thoracic costo-vertebral forms is one of quantity, and the costal appendages of both are those which show this quantitative difference. \u2014 The ribs of the thorax are proportionably larger than those of the loins. In the thorax the costae (4 of a, fig AVI.) appear articularly connected with the centrum (5). In the loins the costae (4 of B, fig. 447.) are fixed or anchylosed to the vertebral centrum (5); but this state of anchylosis is by no means constant ; and when they articulate freely with the centra of the lumbar\n* The \u201c tubercle \u201d is, in human anatomy, accounted as.a process specially characterising the lumbar vertebra as distinct from the dorsal vertebra, in which latter the tubercle is supposed to have no counterpart.\nt Cruveilhier states, as a peculiarity.of the lumbar transverse process, that it sometimes remains articularly separate, and simulates the costal character, becoming the \u201c supernumerary rib.\u201d Meckel alludes to the fact also.\nX On referring to the \u201c Homologies of the Vertebrate Skeleton,\u201d I find the following affirmation : \u2014 \u201c Each of the five succeeding segments is represented by the same elements (centrum and neural arch) coalesced, that constitute the so called dorsal vertebra ; they are called * lumbar vertebra ; \u2019 they have no ossified pleur apophyses.\" Professor Owen\u2019s \u201c pleurapophysis \u201d is the rib or costal appendage of his typical vertebra. While he states, therefore, that the lumbar vertebra has no pleurapophysis, he means that it has no rib or costal piece. This oversight (which, with all respect, I believe it to be) has arisen from the evident error of mistaking the lumbar transverse process as being the counterpart or homologue of the dorsal transverse process, which, if such were the case, would leave the lumbar vertebra without a rib.\nvertebrae, then the elements (4) are as ribs seen in f,fig. 444.\nProp. IX. The sacral vertebrae develop costal appendages.\u2014If it can be demonstrated that the first sacral vertebra is developed of nuclei equal in number, and identical in situation, in form, and in mode of growth with those which are proper to lumbar vertebrae, then we may account both lumbar and sacral vertebrae as homologous with the costo-vertebral thoracic form. And it does appear that the sacral vertebra (fi,fig. 448.) is actually fashioned\nFig. 448.\nof the same number of elements. For the serial order of nucleary deposition throughout the whole length of the spinal axis proves that the anterior nucleus (4) of the lateral mass (3, 4) of the sacral vertebra (b) is the true homologue of the so called \u201c transverse process \u201d (4) of the lumbar vertebra (b,fig. 447.), and of the costa (4) of the thoracic form (a, dg. 448.) and of the anterior half of the cervical transverse process (4, fig. 445.). All these pieces hold serial order ; all are autogenous growths ; all are posited in the same relation with respect to the other vertebral pieces (1, 2, 3, 5) of the cervical, dorsal, and lumbar forms. Now, having once determined the proper identity of the anterior nucleus (4) of the lateral mass (3, 4) of the sacral vertebra (b,fig. 448.), it becomes easy to recognise the homological cast and relation of all the other pieces of the sacral vertebra. The posterior half (3) of the lateral mass of the sacral vertebra (b) is the counterpart of the \u201c tubercle \u201d (3) of the lumbar vertebra (b)u/%.447.), of the transverse process (3) of the dorsal vertebra \u00c7a, fig. 448.), and of the posterior half of the transverse process (3) of the cervical vertebra (fig. 445.). The spinous process ( 1 ), laminas (2, 2), centrum, or body (5) of the sacral vertebra (b, fig. 448.) are evidently identical with the like-named parts of all the other vertebrae correspondingly numbered. It will hence appear that sacral vertebras do not differ from other vertebrae ; and that it is an error as to the identity of the anterior nucleus","page":628},{"file":"p0629.txt","language":"en","ocr_en":"SKELETON.\n629\n(4) of the lateral mass of the sacral vertebra (b,j%. 448.), which causes the human anatomist to name this anterior nucleary appendage as the \u201c peculiarity \u201d of sacral form. This anterior nucleus of the sacral lateral mass, I call a rudimentary rib abutting against the iliac bone.\nProp. X. The coccygeal vertebras are deprived, of their costal appendages. \u2014 The serial order in which we find all spinal figures standing, renders it, under comparison, a demonstrable fact, that the coccygeal bones (jz,fig. 449.) are the debris or metamorphosed\nFig. 449.\nremains of true and complete vertebrae, such as a of the thorax. It matters not as an objection to the truth of this idea of coccygeal bones being the minus proportionals of full costo-vertebral quantities, that we now find them wanting many of those elemental pieces which are existing to these latter. For though it be true that it is impossible now to read the same number of elements in the last caudal ossicle (b) which we find elsewhere posited for all other vertebrae of the spinal series, yet I hold it to be also impossible for any anatomist to contemplate the presential character of a caudal bone and remain unproductive of the idea that the caudal bone (b), as a centrum (5), is a proportional left standing after the metamorphosis of all its other parts. If, then, we agree to this, we must also agree to the fact that those very parts (1, 2, 3, 4, of a) which a caudal centrum (such as b) wants, are identical with those same parts which are left standing to other vertebrae. Now, when I find that a coccygeal ossicle (b, 5) holds series with the centra (5) of all other vertebrae, I have every reason to name it as being the centrum of its own vertebra, which has undergone metamorphosis ; and therefore I may conclude that the plus original of the caudal ossicle (b, fig. 449.) is equal to a, or to any other vertebra of the spinal series. It will be sufficient to the present argument, which holds comparison in order to establish the ideas of original or archetype uniformity, that we clearly understand how the original or archetype of a coccygeal bone is equal and uniform with any other vertebra of the spinal axis. The coccygeal bones (b) as nature presents them to us are vertebral centra, having had subtracted from them their spinous (1), neural (2), and costal elements (4); and under this interpretation we nay have as strong an idea of the whole or plus quantity (a) of which caudal bones (b) have been metamorphosed, as if we saw those quantities still persisting entire. The difference between any of the costo-vertebral spinal segments and a\ncaudal bone is like the quantitative difference between a-\\- 5 and a \u2014 b. Thus A^/zg.449., minus the elements 1, 2, 3, 4, equals b ; while b plus the elements 1, 2, 3, 4, equals a.\nProp. XI. The first seven thoracic costovertebral figures are ivhole or plus quantities. \u2014In no one respect do the first seven thoracic costo-vertebral figures (all equal to fig. 450.} differ from each other; in each of them may be counted the same elemental pieces ; and those pieces of each (marked as in fig. 450.) are identical or homologous both as to position, use, mode of growth, number, and linear order. These elements consequently bear the same name in each, and most properly, because the corresponding pieces of each are absolutely similar. Consequently, also, the whole quantities (such as Jig. 4f0.), which are\nFig. 450.\ncompounded of those pieces (1, 2, 3, 4, 5, 6, 7), should properly bear the same name ; and therefore I call them sterno-costo-verte-bral circles. There are, then, seven whole segments (such as fig. 449.) of the human spinal axis, which absolutely resemble each other in quantity. These segments are posited in linear order, and by this arrangement they yield an absolute linear uniformity. Such linear uniformity is evidently the result of quantitatively equal figures being posited in serial order ; these figures enclose the thoracic space completely ; and, because they severally manifest an equal number of homologous elements, so is it impossible to read any condition of specific variation between them. As archetypes, or whole quantities, of the mammal spinal axis, these seven thoracic sterno-costo-vertebral figures have no special diversity. When we compare them with one another we discover no more distinction between them than we find between the serial quantities a-\\-b, a+b, a+b. It is quite true, therefore, that there is at least one regional department of the mammalian spinal axis, to which we may apply the name of absolute uniformity, as fittingly as we might apply it to a linear series of circles. And it is, moreover, true that the thing called species is, so far as regards this linear series of plus thoracic figures, as perfectly absent, as if it were nonexistent everywhere. But yet it is possible for nature to work specific variety from out of this linear series of thoracic archetypes (such as fig. 450.). And how may nature effect this ? Just in the same mode as she effects it in the creation of skeletal bodies comparatively contemplated, and this mode is the sub-","page":629},{"file":"p0630.txt","language":"en","ocr_en":"630\nSKELETON.\ntraction of quantity from whole or archetype originals. If nature arrested the development of, or, what amounts to the same result, if she subtracted different elemental parts from different regions of these several thoracic costo-vertebral archetypes ; if she subtracted the spinous process (1) of one, the sternal element (6) of another, the rib (4) of another, or the spinous process, sternal piece, and ribs of another, then the remainders of those once uniform whole plus quantities would represent specific distinctiveness to each other. The remainders of the plus or whole quantities would then be the variable proportionals of such plus figures ; and, being proportionals, would therefore be proportionally, that is to say specifically, various to them and to each other. Therefore I conclude that such species results not by the positing of new and unknown quantity, but by the annihilation or degradation of already known and posited quantity. In the plus figures (such as fig. 450.) we therefore discern not only the already create and positive entity of uniform quantity, but even every condition of possible variety or species which can result by a subtraction of their elemental parts.*\nProp. XII. The five asternal costo-verte-hral forms are proportionals metamorphosed\n* This whole or plus segment of the mammalian spinal axis, to which I give the simple name costovertebral quantity, may appear at first sight to be the same as the \u201c typical vertebra\u201d of Carus, Owen, and others ; but it is not so in fact, nor are the ideas which I entertain of the plus form, compared with other vertebrae of the same spine or different spinal axes, the same as theirs. I do not, for example, think it necessary to see in the typical form so many elements and parts as those which Professor Owen names, in order to render it inclusive or archetypal of all varieties of vertebr\u00e6, which, in addition to the centrum, the neural arch and spine, and the costal haemal arch and spine, seem to produce such other elements as he calls zygapophysis, diapophysis, pa-rapophysis, distinct. If I can prove that the ventral costo-sternal pieces, under a process of metamorphosis or degradation, suffer for the creation of such variety as we find ventrad of all vertebr\u00e6 whatever, then must it be evident that the simple costovertebral quantity, as I have drawn it, is all-sufficient as the archetypal whole composed (dorsad) of a neural arch and spine, and (ventrad) of a h\u00e6mal arch and spine, together with their point of union\u2014the vertebral centrum. If I can show that the lumbar \u201c transverse process \u201d and the anterior piece of the cervical transverse process (both of which are named \u201c parapophysis \u201d by Mr. Owen) are actually of costal growth, \u2014 the remains of the degraded plus ribs of a thorax, then there will he no need of them as distinct elements from ribs in my archetype or plus figure. Neither will it he required for my typical spinal figure that I should introduce into its proportions the parts called h\u00e6mal arch and spine (the chevron bones) as things distinct from the ventral costal circles (the pleurapophyses),whileI see good reason to believe the former to be the ribs themselves somewhat degraded. In short, while I see it ossible to interpret many of those elements which ave been gathered together by the philosophic anatomist, as being necessary to the sum of his typical form, to be in reality but varying proportionals of the same whole quantity, so shall I be enabled to divest my typical form of all needless complexity, and set up simplicity in its stead.\nfrom five sternal costo-vertebral plus quantities.\u2014 The thoracic region of the human spinal axis consists for the most part of twelve costo-vertebral spinal segments. Seven of these enclosing space completely, arch forward and join at the sternal median line {fig. 450. 6). Five of these (such as fig. 451.)\nFig. 451.\ndo not enclose thoracic space completely, but fall short of this sternal median line (6) more or less (as at point 7, fig. 451.); and in this respect the five asternal costo-vertebral segments are specifically distinct from the seven sterno-costo-vertebral plus forms. This distinction or species is evidently owing to the subtraction of costo-sternal quantity (7 to 6) from the asternal five forms (such as fig. 451.), which costo-sternal quantity is persistent for the seven sternal forms (such as fig. 450.). The loss or subtraction of the sternal piece (from 7 to 6, fig. 451.) becomes the advent or presence of the specific difference between figs. 450. and 451.; and hence it becomes clearly apparent that the law which exercises in creation of such difference between the sternal and asternal spinal segment is one of subtracting quantity from whole or plus forms, from which it is self-evident, that as the quantity of a sternal element and sternal costal pieces is that which is subtracted from the now asternal costo-vertebral segment {fig. 450.), so the original or plus quantity of this latter figure is of sternal costo-vertebral integrity or entirety, as I have drawn it in dotted outline for fig. 451.\nProp. XIII. The five lumbar vertebr\u00e6 are proportionals metamorphosed from five sternal costo-vertebral archetypes. \u2014 The seven sternal costo-vertebral circles are succeeded by the five asternal costo-vertebral proportionals, and these latter by the five lumbar vertebrae. In this series of spinal segments it is easy to distinguish a descending scale of proportional quantities, whose only difference is one of quantity. This quantitative difference is exercised upon the costal elements only. In all other respects the lumbar and thoracic segments are similar ; for in both orders of structures we find the same elements, such as spinous processes, transverse processes (the tubercle being the transverse process of the lumbar vertebra), centra, and neural arches. In both we also find the costal appendages, but these are not of equal growth or quantity. It is quite true, however, that the sternal costa is serially succeeded by the asternal costa, and this by","page":630},{"file":"p0631.txt","language":"en","ocr_en":"SKELETON.\n631\nthe lumbar \u201c transverse process \u201d or costa ; and this serial order clearly indicates that these are of the same original, but created specifically diverse by undergoing metamor phosis quantitatively. The originals, therefore, of the lumbar vertebrae must have been such as the sternal costo-vertebral circles, and I have drawn this original quantity in dotted outline for fig. 452., for it is true\nFig. 452.\nthat the presential proportional condition of lumbar vertebrae, consisting of the elements 1, 2, 3, 4, 5, fig. 452.), manifests no other variety or species to the archetypal quantity 1, 2, 3, 4, 5, 6, 7, elsewhere persisting, than a simple quantitative variety.\nProp. XIV. The sacro-coccygeal series of vertebrae are proportionals degraded from sternal costo-vertebral circles.\u2014That which is true of lumbar vertebrae, compared with thoracic segments, must be true of sacral vertebrae compared with the same. For as it seems that lumbar vertebrae are the proportionals of sternal costo-vertebral circles, so must sacral vertebrae, which are developed of elements identical in all respects with those of lumbar vertebrae, be proportionals of the like whole quantities or originals. And this is what I affirm of both sacral and coccygeal spinal segments.\nFig. 453.\n._______________\nThe last caudal bone, equal to the centrum (5, fig. 453.), being a spinal centrum itself, is the vanishing point of the series. The next degree of subtraction is annihilation of all quantity proper to the costo-vertebral original whole quantity, the complement of which I have drawn as the parts marked 1, 2, 3, 4, 6 around 5, fig. 452., thereby equating it with the plus thoracic form.\nProp. XV. The seven cervical vertzbroe are proportionals degraded from seven sterno-\ncosto-vertebral whole quantities. \u2014 The same elemental quantity which is proper to a lumbar vertebra is to be found in a cervical vertebra. In both (vide figs. 445. and 447.) we distinguish the centrum (5), the neural arch (2), the spinous (1), and transverse processes (3), and the costal rudiments (4). In both we find that the difference which they manifest on comparison with the costo-vertebral thoracic archetypes is simply a difference in costal quantity ; and hence the same reasons which have been here advanced for regarding the lumbar segments as proportionals of sterno-costo-vertebral circles, may be also applied as proof of the truth of the interpretation that cervical vertebrae (such as fig. 454.), are also proportionals of the like\nFig. 454.\nwhole originals, and therefore I have equated it with the thoracic whole quantity.\nProp. XVI. The mammalian spinal axis consists of a series of segmental quantities, whose only variety or specific distinction depends upon proportioning from whole thoracic quantities. \u2014The truth of this proposition has been established by the foregoing remarks. All the spinal segments of those regions of fig. 455., named cervical, thoracic, lumbar, sacral, and caudal, are not uniform, because they are not equal quantities. A cervical uniformity throughout the spinal axis would require that all the serial segments stood in cervical quantity. A lumbar uniformity would require all the serial segments to be of lumbar quantity. The same with respect to sacral uniformity; and the same of caudal uniformity. A thoracic uniformity would also require the spinal axis to be of thoracic sterno-costo-vertebral quantity from cranium to the other extreme of the same linear series, such as is represented in fig. 455., where the ribs are indicated in dotted outline in the neck from 1 to 7, and in the loins from 20 to 24. Tn neither of these conditions is the mammal spinal axis developed; and therefore it is that the original plus uniformity of all the segments from 1 to 25 is interrupted, the serial quantities being now developed of thoracic or plus, and of minus or cervical and lumbar, &c. proportions. Now as to the just interpretation of the natural law which creates this figure 455., thus composed of spinal segments in plus and minus variety, I apprehend that it is more rational to regard nature as being an artificer who, after creating a prime-model of whole or entire dimensions (such as fig. 455.), with the ribs\ns s 4","page":631},{"file":"p0632.txt","language":"en","ocr_en":"632\nSKELETON.\narul sternum drawn at neck and loins, as well neck and loins, than to understand her as as thorax, degrades this prime-model to the having first given creation to an ens of dimensions of a specific or proportional lesser, proportions (such as fig. 455.), with variety, by obliterating costal quantity at the cervical and lumbar vertebrae lesser than\nFig. 455.\nThe Mammalian Skeletal Axis,'\nShowing in dotted outline at the neck and loins those costo-sternal quantities which, if present, would render these regions equal to, and uniform with, the thorax.\nthose of the thorax, and then varied all other forms to this ens by a superaddition of new and hitherto unknown elements. The former idea is that which I am endeavouring to establish throughout these propositions. Original uniformity, or the prime model or archetype, viz -fig. 455., with the costo-sternal quantities at neck and loins, is that figure whose proportions I mean to develop by my mode of comparison ; and the idea that the degradation or subtraction of parts proper to this archetype is that law which becomes the creator of specific variety. When I find that the osseous quantity of a caudal centrum, a sacral, a lumbar, or a cervical vertebral quantity can severally be referred to the like quantities contained in a sternal thoracic costo-vertebral segment*, I entertain the opinion that the latter, as a whole or prime model, has undergone metamorphosis to the creation of such proportional variety as the former instance : and this opinion, I fancy, is more consonant with reason, or is, at least, more pliable for understanding, than to suppose that nature, after having first given creation to the caudal, lumbar, or cervical segments of the spinal axis, created, as it were by after thought, other figures secondary and special to such as\n* Every lesser unit of the vertebral chain finds its quantitative homologue in a part of the greater unit, and all lesser units in the greatest unit, which I therefore name as the archetype. In the following beautiful sentence, Caras expresses his idea of the organic whole quantity compared with the lesser thing or species : \u2014 \u201cLa partie d\u2019un tout organique est incontestablement dou\u00e9e d\u2019un organisation d\u2019autant plus \u00e9lev\u00e9e qu\u2019elle r\u00e9p\u00e9t\u00e9 plus parfaitement en elle l\u2019id\u00e9e du tout, et le tout lui-m\u00eame est d\u2019autant plus parfait qu\u2019il correspond d\u2019avantage \u00e0 l\u2019id\u00e9e de la nature enti\u00e8re dont nous d\u00e9vons reconna\u00eetre que l\u2019essence est l\u2019unit\u00e9 des lois \u00e9ternelles r\u00e9v\u00e9l\u00e9es dans l\u2019infinie diversit\u00e9 de la manifestation.\u201d See C. G. Carus,Trait\u00e9 El\u00e9ment, d\u2019Anatomie Comp. c. xi. p. 26., traduit par J. L. Jourdan; see also Carus, Yon den Urtheilen des Knochen und Schalenger\u00fcstes, fol. Leipzic, 1828.\nthese by the addition of new and unknown elemental structure, such as a thoracic rib and a sternal piece ; for in the absence or presence of certain elements consists all the specific difference between all segments and regions of the mammalian spinal axis.\nProp. XVII. Uniformity of structure is a condition proper to the plus thoracic origi-nals of the spinal axis of the mammalian body. \u2014It is a demonstrable fact, that all the spinal segments of those regions (fig. 455.), named cervical, lumbar, and sacral, differ from the first seven thoracic costo-vertebral circles (those numbered from 8 to 14) by quantity only ; and this quantity is costo-sternal. It is also demonstrable, that the coccygeal segments of the spinal region, represented by the centrum (ft, fig. 453.), differ from the same whole forms by quantity only : this quantity is the neural arch and spinous process, in addition to costo-sternal elements, all of which I have drawn in dotted outline around the caudal centrum (fi,fig. 453.). Now this differential condition, visible between all such spinal segments, being one of quantity only, it must appear evident that the idea of a structural uniformity can alone be established, first by interpreting the present condition of cervical, lumbar, sacral, and caudal segments, as being one of proportional variety ; and second, by comparing them as such with their originals, which I assert to be of sternal costovertebral quantity. If, then, the original or archetypal quantity of a caudal, a sacral, a lumbar, or a cervical segment be a sternal costo-vertebral segment, it will follow that the series of such originals constitutes plus uniformity, as indicated in fig. 455., whose serial units at neck and loins are equated with the thoracic units, whereas the series of such segments as cervical, lumbar, sacral, and caudal quantity constitutes proportional variety or specific difference, created out of the substance of the uniform archetype costovertebral originals. In order to fix the idea","page":632},{"file":"p0633.txt","language":"en","ocr_en":"SKELETON.\n633\nof uniformity throughout the serial line of spinal segments such as they are, we must submit them to a mental process of comparison which is to tell us what they once were. For as it is evident that these segments are only proportionally various, so is it equally evident that their plus originals must be uniform and absolutely similar. When I compare a caudal, a lumbar, or a cervical segment with a sternal costo-vertebral segment, I must acknowledge to a specific difference existing between these bodies ; but then I also have every reason to believe that this specific difference is only a proportional difference* If, then,the cervical, lumbar, or caudal segment shall severally prove to be parts or proportionals when they are compared with a sternal costo-vertebral segment standing at the thorax, it cannot be erroneous to read them as having been metamorphosed from their own originals, such as those of the thorax, and hence 1 conclude that uniformity alone characterises the series of such originals.f\nProp. XVIII. Every spinal segment which is lesser, refers to every spinal segment ivhich is greater ; and all lesser segments refer to that xohich is greatest.\u2014If it be easy to conceive that the last caudal bone (i,y%.444.) is a lesser quantity metamorphosed from such another quantity as the penultimate caudal bone (h, fig. 444.), where can be the difficulty in rationally interpreting both to be as quantities metamorphosed or proportioned from such quantities as lumbar vertebrae (e, fig. 444,), and hence from such segmental quantities as sternal costo-vertebral plus forms (such as fig. 453.). I could not entertain this idea of a caudal bone, if I found that it were an ens holding within its dimensions any elemental part which may not also be found to be contained in the plus form of fig. 450. ; or if it were not the fact that the archetype (fig. 450. or 453.) could undergo a simple graduated metamorphosis of its parts (1,2, 3, 4, 6), so as to simulate any other segment of the spinal axis lesser than itself.J A caudal ossicle,\n* The number of proportionals capable of being struck from a whole quantity being of infinite amount, it will be also seen that the number of species which those proportionals themselves represent are likewise infinite. \u201c Species autem ilia ab-scissio infinite recte vocari possit.\u201d Bacon, Nov. Organon Scientiarum, Aph. 26.\nf The series of the archetypal sterno-costo-verte-bral circles constitutes absolute uniformity ;and when we contrast with this quantitative uniform line this other line of graduated proportional serial quantities, such as the present state of the mammal skeletal, axis exhibits them, we are enabled to estimate the law which has created the line of proportional quantities such as we find it. When the special or proportional thing is contrasted with the uniform whole or complete quantity, the contrast gives the interpretation. If species arise from the infinite subdivision of the line of whole quantities, then this latter, as perfect quantitative uniformity, may be defined as follows : \u2014 \u201c Unitas (uniformitas) est, sine commissura (sine hiatu) continuatio.\u201d Seneca, Natur. Qu\u00e6st. lib. xi.\nJ \u201c The great advantage of this idea of a whole is, that a greater quantity of truth may be said to be\nsuch as the centrum (fig. 453. 5), reminds me as strongly of its original whole quantity, viz. fig. 453., from which it has been metamorphosed as a dorsal spinous process (1, fig. 450.), separated from that thoracic segment, reminds me of the whole of such segment. If it be true that I could never thus interpret the caudal ossicle, if I had not seen the thoracic archetype, this can be no argument to show the error of my interpretation ; for it is equally true, that I could never know of what whole figure the dorsal spinous process was apart, if I had not seen the thoracic segment named costo-vertebral.*\nProp. XIX. Structural uniformity cannot characterise such spinal segments as are proportionally or quantitatively various. \u2014 A cervical segment differs from a thoracic segment by existing quantity ; and the like difference prevails between all other segments of the spinal series, therefore those segments cannot be termed uniform. But though these segments are not uniform by reason of their being unequal things, still it is most true, that they are only diversified by reason of their quantitative inequality. Injftg. 455. all the spinal segments are rendered plus and equal, by supplying in idea the osseous quantities lost at neck and loins.\nProp. XX. Specific variety is none other than proportional variety.\u2014A cervical, a lumbar, a sacral, or a caudal spinal segment is various to a thoracic segment, forasmuch only as the former fall short of those parts which are proper to the latter figure, and therefore I say that specific variety is none other than proportional difference. For when, asin^g. 455 , we equate those segments which are proportionally different, we re-establish uniform series.\nProp. XXI. The knowledge of the differential quantity between all spinal segments renders them exactly uniform in idea. \u2014 Upon holding comparison between one spinal segment and another, when I find that certain persistent parts of the segment of greater dimensions, viz. that of the thorax (fig. 455.), are those which are subtracted from the segment of lesser dimensions, viz. that of the neck or loins (fig. 455.), this is tantamount to the knowledge that the lesser segment has lost those parts which are persistent for the greater. And therefore I say, that in the knowledge of those parts which are wanting\ncontained and expressed in it.\u201d Sir Joshua Reynolds\u2019 Discourses, Discourse xi.\n* The self-evident truth which attends the geometrical axiom, that the whole is greater than its parts, needs no comment to sustain it ; but that the part standing alone per se still refers to the whole quantity of which it is the part, requires to be insisted upon much oftener, for at first sight we are apt, without reflection, to regard it as it is in the light of a perfect figure. How many anatomists are there who never waken to the idea, that every lesser segment of the spinal axis refers to the greater whole quantity ; and yet in this interpretation the law of formation enshrines itself. \u201c L\u2019ensemble de tous les ordres de perfections relatives, compose la perfection absolue de ce tout.\u201d Bonnet, Contemp. de la Nature, part i. chap. iii.","page":633},{"file":"p0634.txt","language":"en","ocr_en":"634\nSKELETON.\nto the lesser, I may idealise it by a mode of equation to uniformity with the greater. For while I find reasons to believe that the spinal segment (fig. 454.), which is now in cervical form as consisting of the parts 1, 2, 3, 4, 5, has lost its sternal piece (6) and most part of its lateral costae or ribs (7), then I have only to supply in idea the sternal piece and eost\u00e6 to the cervical vertebra, in order to equate this segment to the thoracic plus character of fig. 450. The same mode of comparison carried out through all the serial segments of the spinal axis, will likewise render them in idea all equal to thoracic costo-vertebral archetypes, as seen in fig. 455. ; and this is the mode of comparison by which alone the anatomist can understand the law of skeletal formation.\nProp. XXII. Without knowing the full dimensions of whole or uniform quantities, we can never rightly understand the real character of lesser and special forms, and therefore can never otherwise understand the law of formation. \u2014The object of the present mode of comparison is, to ascertain the exact forms of whole quantities or archetypes, and the means adopted to this end is the synthetic mode. This object, and the comparative method by which I here endeavour to prove the existence of it, differs from all other methods hitherto adopted by comparative anatomists in search of the true interpretation of skeletal fabrics and the law of unity in variety. I mean to show that anatomical science can never know the figure of skeletal unity or uniformity until it shall know the archetype or prime model of complete dimensions from which all skeletal fabrics are fashioned ; and, furthermore, that it can never comprehend the source of variety or specific difference until it shall interpret this as attaching to variable figures of osseous quantity degraded from the archetypes, and hence that it can never understand the law of skeletal formation in any other light rationally, unless in the sense of a law of degradation from whole or archetype skeletal fabrics.\nNow it appears to me, that by means of the mode of comparison which I here make use of for ascertaining the whole original or archetype quantity from which such a fabric as the mammal spinal axis (fig. 455.) is fashioned, we may also define as clearly the originals or archetypes of a large number of spinal axes throughout the classes of mammals, birds, reptiles, &c.; for, no doubt, what is true of one form must be likewise true of plural numbers of forms, such as skeletons which manifestly bear a remarkable analogy the one to the other. The same law of degradation by which a cervical, a lumbar, a sacral, and a caudal ossicle happens in the mammal spinal axis, appears to me to give a complete solution of the more extended problem, viz. how it happens that animal spines of all classes present differences in the cervix, the thorax, the loins, the sacrum, and the caudex. For while I find, by comparative reasoning held upon the serial segments\nof the one mammal spine, that a cervical or lumbar, &c. segment has actually lost costo-sternal quantity, and that by this loss it now differs from a thoracic costo-vertebral archetype, it must follow that the original or whole archetype quantity of a cervical or lumbar spinal segment is the equal of a thoracic costo-vertebral segment ; and the very same reasoning lends a true interpretation to all cervical, or lumbar, or sacral, or caudal segments wherever they appear, whether in the class mammalia, birds, reptiles, &c.\nUniformity must, therefore, alone characterise the original archetype series, not only of all spinal segments such as they appear in the one spinal axis (fig. 455.), but the like original archetypal uniformity must be that whole quantity from which all segments of all spinal axes have been degraded. And diversity or specific difference will at the same time get its proper interpretation; for if a mammal cervical vertebra be diverse to a costo-vertebral thoracic archetype by reason of being proportionally different, and rendered so by the simple subtraction of its sternal piece and ribs, then, as the like difference or variety characterises all cervical or lumbar segments of animal skeletons of the classes mammals, birds, reptiles, &c. from all thoracic costo-vertebral archetypes of the same animals, it will hence appear that such diversity or specific variety has originated by the law of proportioning from whole archetype quantities. I draw the conclusion, therefore, that as an archetype series of sternal costo-vertebral segments, ranging from 1 to 24 of fig. 455., is the original of the mammal spinal axis, so may it be inferred that such an archetype series is the original of all spinal axes, whatever be their existing variety ; and the law by which such variety occurs is the simple process of degradation or subtraction from the archetype series of sterno-costo-vertebral segments. There can, I believe, be no other true interpretation of the law of unity in variety than this.\nProp. XXIII. The mammalian cervix is not limited to the fixed number of seven cervical vertebr\u0153. \u2014 A general rule may have exceptions, and anatomists may still indulge the assertion, that \u201c the exception proves the rule but, as I take it, the exception only proves that the rule has a flaw in it, and that such exception can prove nothing more than this, namely, that error rests somewhere in our in-pretations of the law of formation. When I say that there are many grave exceptions to the general rule that the mammal cervix is developed of seven cervical vertebrae, I am but recording facts \u2014 anatomical facts\u2014 which are exceptions to the rule. And while I here endeavour to develop the true evidence of the universal law of formation, I do not purpose doing so irrespective of those exceptional facts, for I believe that they must be interpreted before the law can be established truly. The neck of one species of sloth (b,fig. 456.) possesses nine cervical vertebrae, while the neck of another species (a)","page":634},{"file":"p0635.txt","language":"en","ocr_en":"SKELETON.\t635\ncontains seven. The human cervix (b, fig. wherein the cervix counted only five or six ; 457.) occasionally develops only five or six. I and I have no doubt, that if we dissected have seen some species of sthe monkey tribe other mammalian bodies as frequently as we\nFig. 456.\nA, the neck of the sloth (Bradypus didactylus), representing the costo-sternal quantities lost to the seven cervical vertebr\u00e6 ; b, the neck of another species of sloth (B. tridactylus), exhibiting the loss of costo-sternal quantity, from nine cervical vertebr\u00e6. In both figures it is shown how the numerical difference of vertebr\u00e6 of the cervix depends upon the number of metamorphosed archetypes.\ndo the human subject, we should find also in them many exceptions to the rule which we now call general.\nBut these exceptions will be called \u201c anomalies \u201d by the special anatomist. To this I answer, that if we understood fairly the true interpretation of the universal law, we should forthwith blot out the word anomaly from anatomical nomenclature ; for there can be no anomalies any more than there can be exceptions to the universal law. Anomalies, such as they appear upon the bodies of one species, as, for instance, the cervical ribs (a, b) of the cervical vertebr\u00e6 (6, 7 of b, fig. 457.), are, in reality, not more remarkable to the normal condition of that species than the figure and proportions of one species (a, fig. 456.) are to those of another and different species (b,fig. 456.). The same law presides over ali conditions of formation. *\nProp. XXIV. The number of cervical vertebr\u00e6 in the mammal cervix depends upon the number of archetypal costo-vertebral figures which have suffered metamorphosis.\n\u25a0\u2014Even if it were true that the mammal cervix invariably contains the fixed number of seven vertebr\u00e6, still there would appear no reason why we should not interpret the fact in the following mode, namely, that the seven cervical vertebr\u00e6 of fig. 455. are those proportional osseous quantities left standing after the metamorphosis of the ribs (1, 2, 3, 4, 5, 6, 7) of seven costo-vertebral archetypes. For it is evident that cervical vertebr\u00e6 do,\nlike the thoracic figures, contain costal appendages, although in rudimental proportions. In the cervical vertebr\u00e6 the costal pieces are liable to a plus condition ( a by of b, fig. 457.). In the thoracic vertebr\u00e6 the cost\u00e6 are fully produced.\nFig. 457.\nA, the human cervix, numbering only five cervical vertebr\u00e6 of normal quantity, owing to the presence of a, b, the cervical ribs persistent on the 6th and 7th vertebr\u00e6 ; b, the cervix of the sloth (A. tridactylus ), which numbers as many as nine cervical vertebr\u00e6, in consequence of the metamorphosis of nine costo-sternal quantities.\n* \u201c Tout ph\u00e9nom\u00e8ne dans la nature est li\u00e9 \u00e0 l\u2019ensemble ; et, quoique nos observations nous semblent isol\u00e9es, quoique les exp\u00e9riences ne soient pour nous que des faits individuels, il n\u2019en r\u00e9sulte pas qu\u2019elles le soient r\u00e9ellement ; il s\u2019agit seulement de savoir comment nous trouverons le lien qui unit ces faits ou ces \u00e9v\u00e8nements entre eux.\u201d Goethe, \u0152uv. d\u2019Hist. Nat. Introd. p. xi. traduits par Martins.\nIf it were possible to raise a rational objection to the above mentioned interpretation of the cervical spinal region, I would then remark that \u201c cervical ribs \u201d do still further prove the truth of what I advance concerning this region of the spinal axis. For is it not true that when the sixth or seventh cervical","page":635},{"file":"p0636.txt","language":"en","ocr_en":"636\nSKELETON.\nvertebrae of b, fig. 457., produce the costae a b of greater dimensions than ordinary, these segments of the spinal axis are but resembling somewhat more completely the thoracic costovertebral archetypes (such as 8, c, d, of B, fig. 457.)?\nWhenever, therefore, the sixth or seventh cervical vertebra produces the cervical ribs, I may interpret the occurrence of this \u201c anomalous \u201d fact in this way, viz. that a greatei proportional of the archetype costo-vertebral quantity (such as 8, c, d, of b, fig. 4:57.) remains to the sixth and seventh spinal segment than is generally the rule. Cervical vertebrae, therefore, whether with or without the plus cervical ribs, are still the proportionals of full thoracic costo-vertebral forms ; and the number of cervical vertebrae simply depends upon the number and degree of metamorphosis to which thoracic costo-vertebral forms have been subjected. When the cervix develops seven vertebrae of those proportions, such as we ordinarily find in the mammal body (a, fig. 456.), all we can say of it is, that seven thoracic archetypes have suffered metamorphosis of the ribs to the cervical degree ; and when the mammal cervix exhibits only five or six vertebrae of cervical degree (B,fig. 457.), this occurs by reason of the fact that the seventh vertebra of b is not metamorphosed to cervical degree, but still retains a large proportional of the rib (b). When the mammal cervix (a,fig. 457., or b, fig. 456.) produces nine cervical vertebr\u00e6, then the simple interpretation is, that nine quantities, equal to those of the thorax, and which I have represented in dotted outline, have had the original plus costo-sternal quantity subtracted from them.\nProp. XXV. The presence of cervical ribs subtracts from the number of cervical vertebr\u00e6, and adds to the number of thoracic archetypes. \u2014Whenever cervical ribs (a, b of B,fig. 457. and 458.) are produced upon the sixth and seventh cervical vertebr\u00e6, the numerical\nlength of the cervical region of the mammal spine is diminished to the serial line of five cervical segments, which v/e call cervical vertebr\u00e6 ; and there and then by the occurrence of this fact, which subtracts from the cervical vertebral numbers, the thoracic costo-vertebral spinal region is added to and becomes numerically greater than we ordinarily find it. By as much as the ordinary, cervical region is lessened, owing to the presence ot cervical ribs, by so much is the thoracic region increased owing to the same cause, viz. the presence of cervical ribs. The converse of this condition would happen if ribs were subtracted from the thoracic spinal region ; and we would then find that by as much as the thoracic region was lessened by so much would the cervical region be increased. What other rational interpretation can be given of this condition of balancing between the cervical and the thoracic spinal regions except this, namely, that the numerical difference of both regions occurs by the presence or absence of full costal forms ; and that the condition of either region of the spinal axis is influenced by the simple law of subtracting the ribs from whole thoracic costo-vertebral quantities.*\nProp. XXVI. The length of the thorax depends upon the number of persistent costovertebral archetypes. \u2014 When I say that the numerical length of the cervix depends upon the number of costo-vertebral archetypes which have undergone a metamorphosis of osseous quantity down to cervical degree, it will follow that the numerical length of the thoracic region must depend upon the number of those original archetype costo-vertebral figures left standing in spinal series. That same law of formation which influences the numerical length of one spinal region must also influence the numerical length of the adjacent spinal regions, and so we invariably find this to be the case. When the cervix of fig. 458. produces cervical ribs a on the vertebiv 6, and\nFig. 458.\nthe next succeeding, the thorax is increased. When the loins produce lumbar ribs, succeeding the vertebra 19 b, the thorax is still increased. When the thorax is numerically lessened, by subtracting the ribs a b from the vertebr\u00e6 6 19, the cervical or lumbar spinal regions are numerically increased. Now all this variation in the spinal regions no doubt depends upon the number of persistent libs, whether normal or abnormal. The degradation of the costo-vertebral ar-\nchetype whole quantities, is the law which produces all minus or special variety, and\n* As it seems that the presence or absence of the costal pieces varies the quantitative character of the vertebr\u00e6, making them thoracic by their plus presence, and cervical by their almost total obliteration, so the reader will, from this expression of the fact, readily gather the tendency of my remarks, which is this, namely, that the archetypal quantities of the cervical spinal region are equal to those which are still persisting for the thorax in full stemo-costo-vertebral proportions. This, be it right or wrong, is","page":636},{"file":"p0637.txt","language":"en","ocr_en":"SKELETON.\t637\nyields the mammal spine as it is, normally or abnormally.\nProp. XXVII. The numerical length of the lumbar spinal region depends upon the number of archetypes subjected to metamorphosis. \u2014The first lumbar vertebra, that which succeeds 19, b, fig. 458., counts twentieth from the occiput, and thirteenth after the last cervical vertebra, when this latter counts seventh from the occiput ; and it is according to the character of the costal appendages of this first lumbar segment of the spinal series, that we are inclined to regard it as belonging to the category of thoracic or of lumbar spinal segments. When it produces articular cost\u00e6, it stands in true thoracic character, and adds to the number of thoracic segments, at the same time that it subtracts from the number of lumbar vertebr\u00e6. In this respect, namely, that of influencing the numerical series of the spinal regions according as the ribs are standing plus upon it or otherwise, this first lumbar vertebra is similar to the seventh cervical vertebra. As the numerical length of the cervix depends upon the presence or absence of cervical ribs, produced from the seventh cervical vertebra, and as this very condition influences also the length of the thoracic series, so does the numerical length of the lumbar region depend upon the presence of lumbar ribs produced in plus or minus dimensions from the first lumbar vertebra ; and this is the very fact which also influences the length of the thoracic series. The inference to be drawn from these facts is obvious enough. The abnormal as well as the normal conditions of the lumbar spine, in regard to the ribs, prove that lumbar vertebr\u00e6, as well as cervical vertebr\u00e6, are proportional figures degraded from the costo-vertebral thoracic archetype quantities such as I have drawn them in fig. 455., from 1 to 24.\nProp. XXVIII. The numerical length of the sacral and coccygeal series is not fixed, and this is owing to the same fact of archetypes undergoing metamorphosis.\u2014 Though the human anatomist speaks of a spinal figure under the name of first sacral and first coccygeal vertebra, it is not hence to be inferred that this form presents, in all human spinal axes of a fixed and invariable character, either as to osseous quantity or numerical position. In order to prove that such is the changeable character of the form named sacral and coccj\u2019geal vertebr\u00e6, we have only to fix attention upon its numerical situation in several spinal axes of even human species ; and we shall find that the first sacral vertebra of one spine is the last lumbar vertebra of another spine. In like manner we shall see that the first coccygeal\nthe idea I wish to create as contradistinguished from the ideas promulgated in \u201c The Homologies of the Vertebrated Skeleton,\u201d where I find that the author, in his figures of the archetype of mammalian, avian, and reptilian forms, leaves their cervical regions standing in their class proportions, as though these were \u201c archetypal,\u201d \u201c the general,\u201d \u201c the fundamental type.\u201d\nvertebra of one spine is the fifth sacral of another spine. In the \u201c normal \u201d condition of the human spine, the first sacral vertebra (fig. 455./) counts as the twenty-fifth reckoning from the occiput ; but if we will compare and examine a large number of human skeletal axes, we shall see that the twenty-fifth spinal segment or vertebra is not always standing in sacral condition. I have found that this twenty-fifth spinal vertebra is sometimes in lumbar and sometimes in sacral form, a circumstance which proves that sacral character is mainly owing to the juxtaposition of the iliac bones. Upon whichever vertebra of the lumbar spine, whether it be/ or the one before or behind f fig. 455., the iliac bones abut, this determines its sacral character. This sacro-iiiac junction does not always occur between the twenty-fifth vertebra of the human spinal series and the iliac bone. I have occasionally seen it at the twenty-fourth and at the twenty-sixth numerical vertebra of spinal series. When the sacro-iiiac junction happens between the twenty-fourth vertebra and the iliac bone, the human lumbar spine reckons only four vertebr\u00e6, provided the last thoracic be the nineteenth. When, again, this junction takes place between the twenty-sixth vertebra and the iliac bone, then the lumbar spine reckons six vertebr\u00e6 provided always the last thoracic costo-vertebral segment be the nineteenth. These variations in the numerical length of the lumbar spine, occur according to the spinal position of the iliac spinal junction ; and it will hence appear that the sacro-coccy-geal series of spinal forms must also be influenced by the same facts.\nProp. XXIX. A comparison of the same numerical vertebra in all human spinal axes will prove the truth of the present interpretation of the law which governs the development of all vertebral forms, not only in the same spine, but all other spines. \u2014 When I say that the seventh cervical vertebra of fig. 455. is a proportional metamorphosed from its own costo-vertebral archetype or whole quantity, and which archetype is the equal of that which stands as the first thoracic costo-vertebral form, viz. that marked 8 in /jg.455., have I not a certain proof of the truth of this interpretation, when upon comparing this seventh cervical vertebra offig. 455. with the seventh cervical vertebra of b, fig. 457., or that of fig. 458., I find that the very same numerical seventh cervical vertebra is, in the one skeleton (fig. 455.), of cervical, andin the other skeleton (fig. 458.), of thoracic character. For it is the presence or persistence of the cervical ribs which determines its character in this case as thoracic, and it is the absence or rudimentary condition of the ribs which in the other case stamps it as cervical. Again, when I say that the twentieth spinal vertebra of /g.455., reckoning after the occiput, and which twentieth vertebra is the first lumbar vertebra, must be considered as a proportional or lesser form metamorphosed from such another whole archetype as the","page":637},{"file":"p0638.txt","language":"en","ocr_en":"SKELETON.\n638\nthoracic costo-vertebral figure, have I not a proof of the truth of this l'eading in the fact, that this twentieth spinal vertebra in one spine presents in lumbar form, and in another spine in thoracic costo-vertebral form. How much closer can we urge the science of comparison to yield to us the secret of nature\u2019s law of formation than by comparing the same numerical vertebra with itself, and discovering that it is proportionally diverse in several individuals of one and the same species ? If, therefore, the same vertebra be in many individuals in all those same conditions of proportional variety in which we find all vertebras throughout the serial order of the one spinal axis from atlas to the last coccygeal nodule, \u2014 if this same vertebra (seventh) shall prove, upon a comparison of it in many animal skeletons, of the same variable proportions as we find to exist between a cervical, a thoracic, a lumbar, a sacral, and a coccygeal vertebra in the same spine, it must be evident that the law which governs the proportional variety of the same vertebra in many animals is the same as the law which governs the proportional variety of all vertebrae in the one animal. So true is this that I hold it to be possible to take the same spinal vertebrae of normal and abnormal condition from a plurality of skeletons, and construct with them a spine of the same quantitative variety as it exhibits in the serial line of cervical, thoracic, lumbar, sacral, and caudal vertebral regions.\nProp. XXX. The anomaly is a link in the chain of form.\u2014False interpretation of the law of form is the source of all those conditions which are spoken of as being anomalous to the law. When anatomists name cervical or lumbar ribs as being anomalous to the human neck or loins, it is a proof that they do not understand the law of development which governs the human and all the general connected chain of special variety. The anomaly (6 a of fig. 458.) is to the normal form of the same cervical vertebra of fig. 455. just what one normal form (19 b, fig. 458.) is to the other before or behind it in series. The cervical and lumbar ribs are to the cervical and lumbar vertebrae just what the thoracic ribs are to the thoracic vertebrae. And the seventh cervical and first lumbar vertebrae, whether these produce the rib in plus or in rudimental form, are to each other just what ordinary cervical and lumbar vertebrae are to thoracic costovertebral archetypes, namely lesser quantities metamorphosed from greater quantities. Hence does it plainly appear that normal as well as abnormal cervical and lumbar vertebrae are alike only proportionally various to thoracic costo-vertebral archetypes, and hence may it be understood that all variety, whether normal or abnormal, springs by the simple metamorphosis of the archetypes, indicated in dotted lines at the neck and loins of fig. 455. While human anatomists falsely interpret the ordinary cervical and lumbar vertebrae as being whole quantities, then every elemental structure which occurs plus upon a cervical\nor lumbar vertebra, will by them be named \u201c anomalous.\u201d* Cervical and lumbar ribs are thus accounted anomalies. But when we shall regard cervical and lumbar vertebrae through the medium of the idea here entertained of them, viz. that they are lesser things degraded, proportioned, or metamorphosed from greater whole quantities, such as costovertebral archetypes, then may we reasonably know the origin of cervical and lumbar ribs, and interpret these as being larger proportionals of the costo-vertebral archetypes than what we ordinarily find in cervical or lumbar regions.^\nProp. XXXI. All the spinal segments of all classes and species of vertebrated animals are only as the variable proportionals of sterno-costo-vertebral archetypes. \u2014 A comparison of those several regions of the spinal axes represented in fig. 459. will prove the truth of the assertion, that the law of formation by which all skeletal species are produced, and the law which produces the regional variety of cervical, thoracic, lumbar, sacral, and caudal in the one skeletal axis, are one and the same in operation. When I take the cervical spine of a bird (a b) (the ostrich), and compare it with the lumbar spine (c d) of the same animal, I find that both regions of the same spine present the like proportional character. The segment (b, atb,c, rf), which is the thoracic sterno-costo-vertebral archetype or whole quantity, is preceded by a series of proportional quantities gently graduated and declining into the cervical minus figure marked a, a. In like manner (c, a, b, c) the archetypal sterno-costo vertebral quantity, the last of the thoracic region, is succeeded by a series of proportional quantities, graduated in the same way, and declining into the lumbar minus figure marked d, a. Again, when I compare the human cervical spinal region (e f) which \u201c anomalously \u201d produces cervical ribs, with a b of the bird\u2019s cervix, which normally de-velopes the cervical ribs, I only find a manifestation of the same law. And the bird\u2019s lumbar spine (g h) is only in the same way proportionally characterised as the bird\u2019s neck (ab), or the mammal neck (ef), or the\n* \u201c La loi de la continuit\u00e9 porte que la nature ne laisse point de vide (anomalie) dans l\u2019ordre qu\u2019elle suite.\u201d Leibnitz, \u0152uv. Philos. Nouv. Essais, liv. iii. p. 267.\nf The continuity of the chain, not only of an animal kingdom, but even of the serial spinal axis, is so evident a truth, and so sound a generalisation, that when any form shall appear abruptly interrupting this continuity, and, as it were separating members of the chain apart and isolated from each other, it may be taken for granted that we are ignorant of its true nature, and its general and special relations to all other units of the series. The true object of science is the discovery of such points of analogy as will relate the anomalous form to the general chain of which it is a unit. The differential character of the thing or things is that which strikes the uninitiated at first sight always. \u201c Itaque convertenda plane est opera ad inquirendas et notandas rerum similitudin\u00e9s et analoga, tam in-tegralibus quam partibus: ill\u00e6 enim sunt, qu\u00e6 naturam uniunt, et constitnere scientias incipiunt.\u201d \u2014 Bacon, Novum Organum, aph. xxvi.","page":638},{"file":"p0639.txt","language":"en","ocr_en":"SKELETON.\n639\nlizard\u2019s neck (i k), or the lizard\u2019s loins (l m). Now as all the units of these several regions\nFig. 459.\nA b, c d, the neck and loins of the ostrich ; e f, the human cervix, with cervical ribs ; G h, the loins of a mammal ; I K, the neck of a lizard ; l m, the loins of a saurian (crocodile) ; n o, a part of the ophidian thoracic skeleton.\nof the same and of different species, evidently illustrate the simple law of the archetypal plus ens of the thoracic sterno-costo-vertebral quantity, undergoing a graduated metamorphosis into less quantities of a neck or loins, so I have equated in dotted outline, all those parts which the minus quantities have actually lost ; and thus I have in idea given creation to their whole or plus originals ; and the reader will observe that by this very mode of equation between the plus and minus segments of AB, CD, EF, G H, IR,LM, I have\nequated them likewise with the plus series n o, which represents part of the ophidian thoracic skeletal axis. The fact likewise may be noticed in this place, which will be more fully considered hereafter, that in fig. g h the parts b, c, d, which are represented in dotted outline as the quantity lost to the shortened ribs a, a, are those very structures which in the saurian venter opposite its lumbar spine l m, appear as the ventral ribs ([c, c), joining a ventral sternum ([d, d) ; and there appears ventrad of the saurian cervix (i k) that series of osseous pieces marked c, d, amongst which I find the bones (c*c*), known as clavicles and coracoids. Are these clavicles and coracoid bones which appear ventrad of the cervical spine, in reality only as persistent parts of the whole sterno-costo-vertebral archetypes ?\nFig. 460.\nA, the seventh cervical vertebra of the human neck ; b, the seventh of a bird\u2019s neck ; c, the seventh of\na serpent\u2019s spinal axis ; D, the seventh cervical vertebra of the human neck, producing a, b, the cervical ribs ; e f, g h, vertebral segments of the ostrich, taken from the caudex e, neck f, loins g, and thorax h.\nWhen I compare all those spinal regions of several species of animals represented in","page":639},{"file":"p0640.txt","language":"en","ocr_en":"640\tSKELETON.\nfig. 459., I find that the difference between them is resulting by a subtraction of different parts from each. But when guided by the light of comparison, I supply to each those parts which it has lost, then i render them all equal as whole quantities. Now, if the question be here asked upon what authority I act in thus equating the minus ens with the plus, by adding to the former that quantity by which it is less than the latter ? I may answer that nature herself teaches me the rule in offering to my consideration the following facts : \u2014 In \u00dfg. 459. a b c d represents the same numerical spinal segment of different animals, and it manifests only a proportional variety. Again, I find that, numerically different vertebrae of the same spine e f g h, exhibit the same proportional variety. Again, I choose numerically different vertebrae from the spinal axes of different classes of animals (a b c, jf%.461.), and they present in the same\nFig. 461.\nabc, vertebrae taken from, the human neck (a), the bird\u2019s thorax (b), and the crocodile\u2019s loins (c) ; i) e F, vertebrae from any region of the ophidian spinal axis.\n%\nproportional variety ; and, lastly, I take di\u00eef numerically different vertebrae from the same spine, and they represent uniformity amongst themselves ; but this uniformity is occurring only by reason of the fact that these units are of equal quantity. Now, upon comparing all those spinal segments of fi'2S. 460. and 461., it becomes manifest that the thoracic or ventral circle a, b, c, which I have supplied in dotted outline for some, indicating the quantity lost\nor substracted, is actually created for others ; and hence it appears that the only difference between them, one and all, is in that degree in which the rib (a b) falls short of the sternal median line c. The law of species therefore appears to be the law of proportioning lesser quantities from whole and complete quantities.\nIt is the metamorphosis of ribs at the neck, loins, sacrum, and caudex, which renders these regions different to the thorax. Between those spinal segments to which the plus ribs are present in one animal fi,figAQ\\.), and those spinal segments from which the ribs are metamorphosed in another animal (a,\u00dfg. 461.), I hold comparison, and I find the rational conclusion, that the parts or ribs (a, b of a) which are absent from one class of vertebrae are identical with the parts or ribs (a, b of b) which are present to another class of vertebrae. And that specific difference, as it exists between two or more animals, is accruing by the loss of known parts, viz. ribs. For which reason I am led to name that skeletal form (n o, fig. 459.) which holds all its ribs (a, b, c,) to be archetype of all other skeletal bodies of the four classes from each of which variable numbers of original ribs are subtracted. And for the like reason, I say, that the thoracic region of the one skeletal axis which holds its ribs is archetype of all other regions of the same spinal axis from which the ribs have been metamorphosed. The law of formation therefore is the metamorphosis of ribs. The original or archetype skeletal axis is therefore one of costo-ver-tebral character from occiput to the extreme caudal tip. The metamorphosis of the ribs of this original, or archetype, or continuous series of costo-vertebral quantities, yields all species of skeletal axes. If all skeletal axes were similar in osseous quantity to the thoracic ophidian (n o,fig. 459.), there would be no specific variety, for all skeletal axes would then be similar to one another. But they are not all quantitatively similar, and this is the reason that they are specifically various, having severally lost various parts, which parts are to be read in the original, the uniformity, the archetype, the uninterrupted serial line of costo-vertebral spinal segments.\nProp. XXXII. The Hyoid Apparatus occurs opposite to the cervical spinal region, where we know costal quantity to be lost. The hyoid apparatus refers to the cervical vertebrae, and consists of their ribs metamorphosed. \u2014 Wherever plus or archetypal or thoracic osseous quantity persists complete in all its parts, there, in that place, we never find a new apparatus posited. It is as impossible for a new or specifically various apparatus to appear where archetypal osseous quantity exists, either among the four classes of skeletal forms, or the four spinal regions of the one skeletal figure, as it is for two things to occupy one and the same place. I call the thoracic sterno costo-vertebral apparatus the archetypal or plus quantity of the spinal axis, and I find","page":640},{"file":"p0641.txt","language":"en","ocr_en":"SKELETON.\n641\nthat, because it is plus quantity, no new apparatus ever appears, or can appear, at that locality which it occupies. Anatomical research has never yet discovered, and never can at any future time discover, a new and hitherto unknown osseous piece of any form or cast whatsoever at that spinal region where the thoracic apparatus stands fully created from the sternum in front to the spinal bone behind. Anatomical science may safely venture to predict that the searcher after variety and specific differences will never find in any skeletal form, whether of extinct species, of existing species, or as yet uncreated species, a new osseous apparatus happening where the complete thoracic apparatus occurs. It cannot occur at this locality, because the full archetypal osseous quantity is already existing in thoracic structure. There is no regional spinal variety, and no new or special apparatus, in the thoracic ophidian skeletal axis, because the full or archetypal osseous quantity already exists in the thoracic form. The ophidian skeleton has neither cervix, loins, sacrum, clavicles, coracoid bones, ventral apparatus, pubic bones, or marsupial bones, because the whole length of its spinal axis is already persistent in costo-vertebral thoracic character. If it be said that these various apparatus are not created for the ophidian skeleton, because they would not suit this particular cast of form, and that the \u201c nihil supervacancum\u201d is a rule with nature in the construction of animal beings, I grant the truth of this most freely ; but still 1 will maintain that this has no power to invalidate my\npresent argument, which is conducted not to disprove design, but to demonstrate that all design occurs by the omission of elemental structure proper to plus archetypal structure. I grant that the ophidian thoracic skeleton, though deprived of all the above-named special apparatus, is as perfect in its own design as the \u201c paragon of animals\u201d himself is, or as any other cast of skeletal form furnished with those same apparatus ; but yet I say that it is as impossible, as it would be unfitting, for creative force to give birth to such a form as the thoracic ophidian, and furnish it at the same time with clavicles, coracoid bones, ventral apparatus, marsupial bones, cervical, lumbar, and sacral vertebrae. Moreover, I assert it to be likewise impossible for creative force to produce any of those apparatus, or all of them, for a skeletal figure, if such figure were not at the same time to manifest a cervical, a lumbar, or a sacro-caudal spinal region. In whatever skeletal form the cervix or loins or sacro-caudal spinal region is developed, in this same form alone can we find the hyoid and ventral apparatus. It is quite true that a skeleton may be found characterised with the cervical and lumbar, &c. vertebrae, and yet not characterised with clavicles, coracoid bones, ventral ribs, or marsupial bones ; but where these do exist, then such a spinal axis as that of the ophidian, consisting of costo-vertebral archetypes, cannot at the same time exist. The continuity of such a thoracic spinal axis must be broken directly any special apparatus, such as 1, 2 of fig. 462., or 1,2,3,4 o i'fig. 463., appears upon it. A thoracic skeletal axis, in\nFig. 462.\nThe cervical spine of the Menopone,\nShowing that the hyoid circles 1, 2 appear as the ribs of cervical vertebr\u00e6, and hold serially related to those ribs 3, 4, 5, 6, 7, which, having been subtracted from the thorax, give to this latter its particular form.\norder to be of what I call full plus archetypal dimensions, should present its spinal segments, one and all, from the skull to the other extreme, in sterno-costo-vertebral quantities, such as the thoracic spinal segments of the human skeletal axis. Upon such a skeletal axis there could not appear such an apparatus as the hyoid structure (1,2 offig. 462. or 1, 2, 3, 4 o\u2019(fig. 463.), or the clavicles, the coracoid bones, marsupial bones, pubic bones, or ventral apparatus, and for this reason, namely, that all the osseous quantity which goes to construct these, when fitness and special design demand their presence in the skeleton, must be drawn from the costal and sternal quantity of the continuous series of archetypes, and in such case the presence or creation of the hyoid species of\napparatus must imply the metamorphosis of the other costo-sternal species of form. Now, the ophidian skeleton itself proves to be imperfect when compared to this standard skeletal figure, consisting of sterno-costo-vertebral archetypes ; for the sternal median structure is lost to the ophidian throughout its entire length. In the ophidian skeletal axis, I find the cervical region, or that division of the spinal segments which immediately succeeds the occiput,having the costae or ribs persisting ; but those ribs are free, that is to say, they do not meet the sternal line in front. The sternal pieces and the sternal ends of the ribs are wanting ; but in that very locality where these should appear, if the archetypal sterno-costo-vertebral segments were perfect","page":641},{"file":"p0642.txt","language":"en","ocr_en":"SKELETON.\nand enclosing thoracic space completely, ap- special design of an ophidian hyoid apparatus, pears the new apparatus named hyoid. The By an actual necessity, therefore, and in the absence of the sternum and sternal ends of relationship of cause and effect, it appears the ribs becomes the presence of the simple that the presence of a hyoid apparatus (1, 2\nFig. 463.\nThe cervical spine of the osseous Fishy\nExhibiting the hyoid apparatus 1, 2, 3, 4, as being the original costo-stemal quantity proper to those vertebras which immediately succeed the occiput. In both figs. 462. and 463. the parts indicated in dotted outline are those quantities of the archetypal series of sterno-costo-vertebral circles which, being subtracted, give to both forms their class characters. If such parts still existed for both forms, these would approach the original character of plus uniformity, and thereby would leave no distinction between the hyoid apparatus, 1, 2, 3, 4, and the thoracic apparatus, 5, 6, 7. In both figures it will be marked that the variable number of hyoid circles depends upon the variable number of those cost\u00e6 which have suffered metamorphosis.\nof fig. 462.) must be the metamorphosis of a costal apparatus at those spinal segments which immediately succeed the occiput, and the same appears true of every other special apparatus produced upon the skeleton form. The appearance of any or all kinds of special apparatus implies the metamorphosis of all or some of the costal and sternal quantities. Consequently, therefore, it must follow that as the original costo-sternal apparatus of the cervical spinal segments may be regarded as homologous with the thoracic costo-sternal apparatus, so will the hyoid apparatus (l, 2, 3, 4, fig. 463.), which is constructed of the cervical costo-sternal quantity, bear some analogy, more or less, to the thoracic apparatus (5, 6, 7, 8, 9, 10, fig. 463.). In all skeletons I see an analogy, more or less strongly marked, between not only all hyoid apparatus as special designs (fig. 462,463.), but between these and the thoracic apparatus. The source of this structural analogy, no doubt, is, that the hyoid apparatus (1, 2 offig. 462., and 1, 2, 3, 4 of fig. 463.) is specially modified from the original structure at the cervix, which structure is costo-sternal proper to the cervical spinal region, and, as such, is the true structural homologue of that apparatus which elsewhere constitutes the thorax. The hyoid apparatus, at one spinal region, is not the thoracic apparatus at another spinal region ; for to assert this would be as absurd as to say that the thorax of one skeleton was the thorax of another ; in other words, as to assert that duality was unity. How can the hyoid apparatus (1, 2, 3, 4 of fig. 463.) be rationally named the thoracic apparatus, when both apparatus may exist at the same time in the same skeleton ? When I see the hyoid apparatus (1, 2, 3, 4) of a fish (fig. 463.5 existing with\nthe thoracic apparatus (5\u201410, fig. 463.), and both the same apparatus existing in a mammal skeleton (a, b, 8\u201419, fig. 455.), why should I therefore say that the hyoid apparatus of the fish was the thoracic apparatus of the mammal pushed upwards into the fish\u2019s throat ? If the hyoid apparatus of the fish were the thoracic apparatus of the mammal, then, strictly speaking, the fish could have no hyoid apparatus at all, and wherefore should we still continue to call that hyoid which in reality was thoracic ? Evidently anatomists are only disputing abo\u00fct the shadow of nomenclature in their ignorance of the real entity of form, and the law which modifies to infinite variety. Evidently, while they record how unity or uniformity is varied, they cannot describe or figure the character of unity, and they never will, so long as they dispute about variety without first ascertaining the source of this variety. What is the truth concerning the source of this remarkable analogy between all hyoid apparatus as such (in figs. 462,463.), and all thoracic apparatus as such ?\t1 believe the source of the analogy to\nbe this, namely, that the thoracic apparatus happens at variable localities of the spinal axis, according to the position whereat sterno-costo-vertebral archetypal structure persists, as from 8 to 19 offig.455., and 5 to 10 offig. 463. This thoracic apparatus may, according to necessity, persist at any region of the spinal length, or at all regions, because the original archetypal skeletal axis is one of a continuous series of thoracic segments. Where it does persist, as in fig. 463. from 5 to 10., there no new apparatus can recur ; but where the thoracic apparatus has undergone metamorphosis, as at cervix 1 to 7 of fig. 455., and 1 to 4 offig. 462.or463., there and there only a new special apparatus, such as the hyoid, can happen.","page":642},{"file":"p0643.txt","language":"en","ocr_en":"SKELETON.\n643\nWhere this original or archetypal thoracic structure suffers metamorphosis, as at the neck, there the hyoid apparatus appears as part of the original thoracic quantity, and hence it is that the hyoid apparatus, as such, bears an analogy with the thoracic apparatus as such, because the original of the former is thoracic quantity. When this original thoracic quantity undergoes metamorphosis immediately after the occiput, then the vertebral cervix is formed, and also the hyoid apparatus below it. As both these have come by the metamorphosis of costo-vertebral quantity, so do we find them bearing analogy to those segments, next succeeding them in spinal series,\u2014 those segments, namely, which persist as whole archetypes, and constitute the thorax.*\nProp. XXXIII. The Ventral Apparatus occurs opposite to the lumbar spinal region, where we understand that costal quantity is lost. The ventral apparatus refers to the lumbar vertebrae, and consists of their ribs metamorphosed.\u2014With the mere change of name from hyoid to ventral apparatus, I may apply the foregoing remarks, which prove that the hyoid apparatus has come of the metamorphosis of the ribs of cervical vertebrae, to demonstrate, also, that the ventral apparatus ( 1,2,3,4,5, 6, 7, fig. 464.) has come of the metamorphosis of ribs proper to the lumbar vertebrae. As the original or whole archetypal quantities from which the hyoid apparatus and the cervical vertebrae have been metamorphosed are of thoracic or costo-vertebral proportions, so, in like manner,\nFig. 464.\nThe lumbar spine and ventral apparatus of the Crocodile,\nShowing; that the ventral ribs (1 to 7) are the proper continuations of the lumbar costal pieces, b, c, d, e,f, g, h, with which they correspond numerically.\nI believe that the original or whole archetypal quantities, from which the ventral apparatus (1 to 8, /^.464.) and lumbar vertebrae (b to h, yfy.464.) have been metamorphosed, are also of thoracic costo-vertebral proportions. In the ophidian thoracic skeleton, I find that that region of the spinal axis which corresponds numerically to the cervical region of the mammal spinal axis presents in thoracic costovertebral proportions ; and therefore I say, that the true interpretation of the law of formation, which strikes the skeletal neck of the mammal specifically different to the skeletal neck of the ophidian, must be this, viz., that the costo-vertebral original of the mammal neck is equal and homologous to the persisting figure of the ophidian neck ; but that metamorphosis has modified the original quantity of the mammal neck (figA55.) to its existing apparatus of hyoid arcs a b and cervical vertebras, whereas the original quantity of the ophidian neck still persists. In the latter we therefore find the cervix in thoracic costo-vertebral quantity, having appended to it, in front, the\n* Professor Owen considers the first circle of the fishes\u2019 throat apparatus as the only part of it which is homologous to that of other animals, and accounts all the succeeding arches (three or more in number, and all similar to the first, however,) as \u201c appertaining to the system of the splanchno-skeleton, or to that category of bones to which the heart-bone of the ruminants, and the hard jaw-like pieces supporting the teeth of the stomach of the lobster, belong.\u201d See Homologies, &c.\nsimple hyoid apparatus metamorphosed of the sternal elements. In the former we find the cervix consisting of vertebrae with stunted ribs, which are occasionally produced to more imposing proportions, being then called \u201c cervical ribs\u201d and still having appended to them, in front, the hyoid apparatus. The same interpretation will apply, also, to the mammal lumbar spine (fig. 455.), viewed in connection with the fibrous bands named \u201c linece transvers\u0153 \u201d (20 to 24) and \u201c linea alba\u201d (d to e). And still more evidently will the same interpretation apply to the saurian lumbar region (b to h,fig. 464.), and the ventral apparatus (1 to 7) ; for this latter structure is evidently composed of sternal and costal elements. What the hyoid apparatus is to the cervical vertebrae, namely parts of the thoracic original whole quantities, just in the same relation stands the ventral apparatus offig. 464. to the lumbar vertebrae ; for I regard both these latter structures to be parts, likewise, of the thoracic whole quantities. The hyoid apparatus refers to the cervical vertebrae, therefore, just as the costo-sternal structures of the thorax refer to the dorsal vertebrae ; and in the same relation does the ventral apparatus of fig. 464. refer to the lumbar vertebrae. If we seek a proof still further that the original quantities of the cervical and lumbar regions of the spinal axis of any animal are thoracic costo-vertebral quantities, equal to those of the thoracic region of the same animal, we have this proof in the fact, that all the spiral\nT T 2","page":643},{"file":"p0644.txt","language":"en","ocr_en":"\n614\tSKELETON.\nregions of the ophidian are thoracic, and therefore in this skeleton there does not appear a cervical spine, or a lumbar spine, properly so called. If the above observations, respecting the several spinal regions, and the several apparatus thereunto appended, be true, then, however harshly it may seem to jar against reason, in asserting that there must exist the same analogy between a hyoid, a thoracic, and a ventral apparatus, as between the cervical, the dorsal, and the lumbar vertebrae, still I do not hesitate to make that assertion, under the knowledge that the original whole quantities of each region are of thoracic costo-vertebral proportions. I do not mean to say that the apparatus of the vocal throat (a b of fig. 455.), or the respiratory thorax (8 to 19 of fig. 455.), and the digestive venter (1 to 8 ofy&.464.), are identical as osseous quantities, having the same number of elemental pieces in each which we find in one, but what I distinctly repeat is this, namely, that, however broad may be the specific distinctions between the presential characters of a hyoid, a thoracic, and a ventral apparatus, when compared and contrasted with each other, still the law of serial arrangement will, if followed in the one skeletal form, and throughout the whole animal kingdom, prove that they are variable proportional osseous quantities of the same original, viz., the thoracic costo-vertebral continuous series of archetypes : and, therefore, I have united with dotted lines the hyoid apparatus to the cervical vertebrae, and the ventral apparatus to the lumbar vertebrae.\nProp. XXXIV. Clavicles, coracoid bones, and ribs are identical parts of the costo-vertebral whole quantities or archetypes.\u2014It is impossible to tell which of the two bones named clavicle and coracoid, in a bird, is the counterpart or homologue of the bone named clavicle in man. Anatomists are not agreed upon this point at the present time ; and, I may venture to say, they never will be, for this reason, viz., that they believe these bones to be specifically diverse bodies, and holding a permanently fixed character in all animals, when, in fact, they are identical bodies, being severally subjected to the same modification in two or more skeletons. Whichever of these two bones (and it may be either one or the other) is made to assume the functions and connection proper to the thing called clavicle in the human skeleton, will be the clavicle. It is the distinguishing mark of the human clavicle (a b,fig. 465.), to abut by one end against the sternal piece (c), and by the other end (a) against the acromion process of the scapula ; but, strange to say, we find that both these connections proper to the clavicle of the mammal are divided between the two bones named clavicle and coracoid in the bird. The bone named coracoid (d,fig. 466.) in the bird joins the sternum (/), like the bone named clavicle in the mammal ; but it is the bone named clavicle {a fig. 466.) in the bird which joins the acromion process (5) like the bone named clavicle in the mammal. For this reason, I say, that it is not possible to pronounce what bone\nin the bird is counterpart of the clavicle in the mammal, since, evidently, those very articular\nFig. 465.\nconnections which characterise the one bone, called clavicle in the mammal body, are divided\nFig. 466.\nbetween two bones at the same locality in the bird. It is this circumstance which has given rise to so much written controversy* in the school of comparative anatomy.\n1 find that the mammal clavicle (b fig. 465.) joins the first sternal piece (c) by one end\n* In tlie writings of Cuvier, Geoffroy, Carus, Meckel, and others, I find the following statement respecting the identity of the bones called clavicles and coracoids. By one, the furcular bone, at the root of the bird\u2019s neck, is accounted the true analogue of the mammal clavicle. By another, this \u201c coracoid \u201d bone, which is behind the furcular, and articulates with the stemumt is called the analogue of the mammal clavicle. By another, this coracoid bone is said to represent the coracoid process of the human scapula. By another, the two bones, furcular and coracoid, are said to be clavicles proper. One states that the corresponding bone, which occurs at the root of the chelonian cervix, is a coracoid bone ; another avers that it is the counterpart of the clavicle ; another that it may represent either. In the tortoise, the bone is clavicle according to one ; coracoid, according to another. In the cassowary and ostrich, where one of the two bones is rudimentary, a doubt arises as to whether this be the coracoid or the clavicle ; some prove one reading on the bat, some another on the monotreme, some another on the lizard, others prove their own interpretation on the fish ; and Nitsch discovers (?) a small additional rudimentary scapula in the capsular ligament of the shoulder of some accipitres, which he says is proper to the furcular bone, and therefore the furcular bone is a clavicle. I leave the reader to choose his own belief out of these, if it be possible with him.\nI","page":644},{"file":"p0645.txt","language":"en","ocr_en":"SKELETON.\n615\njust as the first thoracic rib (7, 8, fig. 465.) itself does ; and, in this particular, the clavicle is like the rib. The sternal half of the clavicle (b fig. 465.) and the sternal half of the first rib (7, 8) are therefore as identical one with the other as the sternal halves of any other two thoracic ribs of serial order. But I see that while the ribs join the dorsal vertebrae behind, the clavicle joins the acromion process of the scapula laterally. In this latter particular the clavicle differs from the rib. Now, granting this to be a well-marked specific difference between rib and clavicle, I still maintain that there is as broad a difference existing between clavicles of mammals and birds; and also between clavicles and coracoid bones. If change of place at one end from vertebra to acromion process be enough to distinguish clavicle (a, b fig. 465.) from rib (7, 8) in the mammal bod}', so must change of place be sufficient to characterise the bone named clavicle (a fig. 466.) in the bird from the bone so named in the mammal, for the former does not join the sternum (f fig\u25a0 466.), and the latter does abut against that bone. And true it is that the bone named coracoid (d,fig 466.) in the bird joins the sternum (/), like a true mammal clavicle, but yet is not considered the clavicle, because its scapular end (e) joins another process than the acromion. It appears, therefore, all circumstances considered, that the mammal clavicle (a, b,fig. 465.) is as homologous to the rib (7, 8) in sternal respect (c, d) as it is to the bird\u2019s so-called clavicle (a, fig. 466.) in scapular respect (c, b) ; and at the same time it appears that the\ncoracoid bone (d,fig. 466.) of the bird is as similar to the mammal clavicle (a, b,fig. 465.), and mammal rib (7, 8) in sternal junction, as the bird\u2019s clavicle (a, fig. 466.) is to the mammal clavicle (a, fig. 465.) in acromion junction. What, then, is the difference between the rib, the clavicle, and coracoid bone? It is a difference of articular connection, which all three bones appear to share in common,\u2014 a crosswise difference in articular connection, which presents us with reasons equally strong for naming either of these bones ribs, as well as clavicles or coracoids. Viewed all three as clavicles, they share the clavicular character amongst them ; for that clavicular connection which the one has not, the other has. Viewed as ribs, all three, they share the costal character likewise between them, and hence follows the inquiry into truth; namely, whether their originals be ribs, or bodies absolutely distinct from ribs, passing through metamorphosis. I believe them to be ribs, or costal parts of whole costo-vertebral archetypes, and that their difference depends simply upon that act of the creative force which in the process of development bends them from the continuous line of serial costal order, and renders them cleaving articulariy to various parts for the fitness of various special skeletal fabrics. The track of the law of metamorphosis which differences clavicles or coracoid bones from ribs, may be easily followed, if we will enlarge the view, through comparison, and over a sufficient number of facts. As in fig. 467. the rib (k) follows the rib i, 9, in serial order through the thoracic\nFig. 467.\nThe cervical spine of the Crocodile,\nShowing that if in idea we continue the cervical ribs, a, b, c, d, e,f g, h, i, over the cervix, in the same way as we find the thoracic ribs, k, &c., enclosing thoracic space, we then find 8, the clavicle, holding serial order with the costal continuations, 1, 2, 3, 4, 5, 6, 7, which proves the costiform character of the clavicle itself.\nregion, so does rib i, 9, and clavicle 8, taken with the cervical rib h, succeed each other in the same serial line ; and so likewise in fig. 468. does rib e, the coracoid d, and clavicle b, succeed each other in costal order. These bodies are similar by succes-sional position ; and the only specific difference between them, upon which we hang the names rib, clavicle, and coracoid bone, is this, viz., that whilst all three bodies have a sternal articulation (c,fig. 468.), the rib (<?) still holds connected with its proper vertebral piece, while the clavicle (5), and the coracoid\nbone (d) disconnect themselves from their vertebrae behind, and are taken up by the acromion and coracoid processes of the scapula.*\nIny\u00eeg.469. we find the osseous pieces marked 1,2, 3, 4, 5, to be succeeded by the sternal rib 6, which joins the part f and constitutes the costo-vertebral archetypal quantity of the thorax. If, therefore, the serial order of the osseous pieces a,b, c,d,e, continued into the\n* This fact will be more fully illustrated when 1 shall have to define the homological relations of the scapulary members.\nt T 3","page":645},{"file":"p0646.txt","language":"en","ocr_en":"646\nSKELETON.\nthoracic rib, invites the reason to name all these pieces as costiform, wherefore should\nFig. 468.\nThe cervical spine of the Ornithorhynchus,\nShowing that b the coracoid hone, d the clavicle, and e the sternal end of the rib, are serial homologues.\nwe not regard the pieces 1,2, 3, 4,5, continued serially into the rib of 6, as being cos-\ntiform likewise, despite the fact that anatomists have already regarded the pieces 1 and 2 as the coracoid and clavicular bones ? Do we not see in fig. 469. that the parts 1, 2, 3, 4, 5 point to the parts a, b, c, d, e, just as the part 6 points to the part/? If it be said that the parts 1 and 2 (the coracoid and clavicle), being disconnected from the cervical ribs (a and b) are therefore to be regarded as quantities unrelated originally to a, b, I must doubt whether this can efface from the rational mind the belief that the now separated pieces a, 1 or b, 2, taken as whole quantities, equal the costo-sternal form fi 6.\nWhether or not the above-mentioned interpretation as to the origin of the bones called clavicle and coracoid be true, must be seen through the facts as they are here recorded : but be this interpretation as it may, I plainly affirm that the comparative anatomist has no positive evidence, near or remote, directly or indirectly, either by a similarity of structure, or function, or position, or aught else, to regard the cora-\nFig. 469.\nThe cervical spine of a Lizard,\nIn which the cervical ribs, a, b, c, d, e, point to the coracoid bone 1, the clavicle 2, and the pieces marked 3, 4, 5, as their proper continuations, and just as the sternal rib, 6, continues the vertebral rib, f, to the sternal median line.\ncoid process of the human scapula as the counterpart of the bone (d fig. 466.) called coracoid in the bird, or of 2, the coracoid of fig. 469., the reptile.* The anatomist may just as well call the sternum a series of vertebrae (a statement by-the-by which some\n* On referring to the \u201c Homologies of the Vertebrate Skeleton,\u201d I find, in the section \u201c General Homology,\u201d the following opinion, advanced respecting the coracoid bone, that it \u201c is always developed from an independent osseous centre (a rudi-mental representative of the h\u00e6mapophysis), which coalesces with the pleurapophysis in mammalia, and only attains its normal proportions completing the arch with the h\u00e6mal spine (epistemum) in the monotremes.\u201d The reader will not, perhaps, comprehend the author\u2019s meaning in this sentence, taken separate from the flowing context of the work cited. The meaning of the sentence is this : \u2014 The scapulary organ is referred to the occipital vertebra, as the h\u00e6mal arch of this segment of the skull, the scapula is interpreted as its pleurapophysis or rib, and the coracoid bone (process) is accounted the h\u00e6mapophysis appended to the costiform scapula, and thus the typical occipital vertebra is formed. Although I regard the work from which I have quoted to be a lasting monument of learning, research, and inductive reasoning \u2014 a worthy effort in a great cause \u2014 still I cannot concur in the opinion which that work announces respecting the relation between the scapulary member and the occipital vertebra.\nhave made)*, as to say that there is identity between the human coracoid process and the bird\u2019s coracoid bone. However endless may be the whole account of specific difference be-*tween bone and bone, and between one skeletal form and another, still there does appear happily some well-marked limits to the homologies. No one, for example, will torture the bone named scapula into an identity of cast with the bone named rib f ; and I believe that the same absolute difference is possible to be pointed out between the coracoid process of the human scapula and the bone named coracoid in the bird, or that bone so named in the chelonian reptile. The coracoid process of the human scapula is an elemental part proper to the scapula, just as the centrum is a part proper to the vertebra. The bone called coracoid (d, fig. 466.) in the bird abuts against that part of the bird\u2019s scapula where the coracoid process usually appears in mammal scapulae ; but this coracoid bone is not representative of the mammal coracoid\n* De Blainville, Meckel, and Carus entertain this opinion, which certainly has no support from natural evidence.\nf It is true, however, that this very opinion respecting the scapula is advanced by the distinguished author of the \u201c Homologies,\u201d &c.\n-\ni\n*","page":646},{"file":"p0647.txt","language":"en","ocr_en":"SKELETON.\t647\nprocess produced to sternal junction ; and I shall hereafter prove that the coracoid process of the mammal scapula is as distinct a piece from the coracoid bone of the bird, as the centrum of a vertebra is from the costa. In order to understand aright the law of formation, it is as necessary to know what parts are identical and different in two or more skeletons, as it is to know what parts are identical and different in two or more vertebrae ; an error in the one or in the other is fatal to a proper understanding of the law which governs the development of both.\nWhile we view the clavicle (b,fig. 470.) in connection with the cervical rib behind (a), we then find that the entire of fig. 470. represents a quantity equal to the thoracic archetype, inclosing a visceral or haemal space ven-trad, and a neural space dorsad. This same whole quantity of the archetype is also seen in fig. 471., where (b) the furculum joins c, the sternum, and points dorsad to a, the cervical\nFig. 470.\nThe cervical vertebra, with the rib, a, the clavicles, b, and first sternal piece, c, of the crocodile, forming, in their connected totality, the sterno-costo-vertebral whole quantity.\nrib of the cervical vertebra. In like manner fig. 472. shows the dimensions of a thoracic\nFig. 471.\nThe cervical vertebra, with its rib a, pointing to the furcular hone b, and the sternal junction c, which parts in their totality form the sterno-costo-ver-tehral quantity in the albatross.\nwhole quantity when we take (a) the cervical\nrib with (b) the coracoid bone (so called in the bird) and joining (c) the first sternal piece.\nFig. 472.\nThe cervical vertebra, with the rib a, the coracoids b, and the first sternal piece c of the albatross,\nforming the whole quantity.\nWhen the whole quantities of the sterno-costo-vertebral circles suffer a dismemberment of their integral parts, then it is that special or diversified objects first appear\u2014then it is that clavicles become special to coracoid bones, and both to ribs \u2014 then it is that the anatomists pursue, with special distinctions, fragmental plurality, and lose sight of the intelligible form of unity on the whole.\nOsteogenie is constant to the law of serial order. As rib follows rib in serial order\u2014a circumstance which indicates the homological cast of both\u2014so rib, and coracoid, and clavicle, which take serial order, indicate by this same fact their own identity or homological relation. But the mammal\u2019s coracoid process is a part distinct from the bird\u2019s costiform coracoid bone. The former never takes place of the latter, but is a part proper to the scapula alone.*\n* Professor Owen\u2019s idea of the relationship of the mammal scapulary member and its coracoid element to the occipital vertebra, must imply that the coracoid clavicle of the bird is (if the mammal coracoid process and the bird\u2019s coracoid bone be considered by him to be homologous parts) also referable to the occipital vertebra. This homological relation, I am bound to say, I could never discover; and if the asserted relationship between these parts shall be ever received as an opinion true to nature, the learned author is certainly the discoverer. For my own part, however, I must confess myself no convert to the belief that so large an amount of displacement between any two numbers of a whole quantity, such as that which, according to the author, is instanced in the totality of the occipital vertebra, taken with the scapulary limb, ever occurs, but I am rather impressed with the opinion which the immortal Goethe advanced respecting the fixity of place which osseous pieces of the endo-skeleton invariably hold : \u201c L\u2019ost\u00e9og\u00e9nie est constante, en ce qu\u2019une m\u00eame os est toujours \u00e0 la m\u00eame place.\u201d \u0152uv. d\u2019Hist. Nat. p. 41.\nT T 4","page":647},{"file":"p0648.txt","language":"en","ocr_en":"643\nSKELETON.\nWhile clavicles, coracoid bones, and ribs appear identical, we then can readily understand how a bird or reptile may possess two or more clavicles, according as the laws of form shall subject two or more of the original cost\u00e6 to clavicular modification. The clavicles, therefore, of the mammal and the clavicles and coracoids of the bird or reptile being costal quantities under metamorphosis, these bodies are to be regarded as the ribs proper to those cervical vertebrae, opposite to which they appear in all skeletal forms.*\nProp. XXXV. Marsupial bones, pubic and ischiadic bones, and ? ibs, are identical parts of the costo-vertebral whole quantities or archetypes. \u2014 Wherever we find these parts, viz. sternum, rib, and vertebral piece, occurring in skeletal fabrics, we shall never find that they take the place of each other. The sternum, even when appearing isolated from the other parts, is still holding its proper locality at the median line in front. The rib is always found laterally, and the vertebral piece always behind. The sternal pieces hold serial order, and hence we know them throughout all variety of modification. The costae in like manner hold serial order, and hence we also recognise these parts. The vertebral pieces hold their own serial order, and thus we know them. The costal, the sternal, and the vertebral serial orders are never interrupted by the introduction of a new and unknown element among: the bodies which form each serial line. There never occurs among the vertebral pieces behind any other thing which by being difform to vertebrae, may disconnect that vertebral series. The same remarks apply to the sternal bodies in front, and the same to the costal pieces arranged laterally. Every body which holds serial order with the sternal bone is a sternal bone, and constituting sternal serial order. Every body which holds serial order with a vertebral bone is a vertebral bone, and constituting vertebral order. Every body, also, which takes serial order with a rib is a rib, and constitutes costal-serial order. Every body, therefore, which on first sight shall seem to be specifically distinct from that order with which it holds series, is in fact only rendered special in such order by modification ; originally it is identical with all the pieces of that same order.\nJust as the clavicle and coracoid bone hold series with ribs, and are ribs originally, but rendered special by modification, so does it appear that the marsupial, the pubic, and ischiadic bones, which hold serial order with ribs are ribs originally, but now presenting in such conditions of modification as we mark by\n* The same reasoning which leads the author of the \u201c Homologies\u201d to refer thecoraco-scapular arch to the occipital vertebra, induces him to pronounce the mammal clavicle to be naturally related to the atlas vertebra. Now, I cannot understand why the author\u2019s views, which are certainly correct, in so far as he is led to believe the pair of clavicles to be the inferior arch of some one of the cervical vertebr\u00e6, should make choice of the atlas so remote, in preference to that cervical vertebra, opposite which the clavicles appear.\nnomenclateric difference. A clavicle, a cora coid bone, a marsupial bone, a pubic bone, and an ischiadic bone, are thus differently named in order to point to their several specialities of caste. But through these special characters their costiform original character is still visible, and therefore I call them ribs modified. These modifications which clavicles, coracoids, marsupial, pubic, and ischiadic bones present, when contrasted with each other and with ribs, are in reality of no greater amount than those varieties which are apparent among those bodies which we name ribs, enduring as such through the skeletal axis. At the present day we well know that the thing named rib is not necessarily confined to that region of the skeletal axis named thorax. Ribs are found embracing the ventral region of fishes, and all spinal regions of ophidians. Ribs of unequivocal character are also developed embracing the venter of Saurians. Ribs are jutting out laterally from the loins of the draco volans, supporting the parachute of that animal. In fact we can readily distinguish the costal character of many bones, even though they are separated from their proper vertebral centres behind. See these osseous quantities, which project from the sternal bone behind, ensheath-ing the venter of the bird\u2019s, and the Saurian\u2019s skeleton, and standing free from the lumbar vertebral pieces, to which, nevertheless, they refer,\u2014are they not ribs, which special laws have dissevered from the spinal axis behind ? It is not, therefore, necessary to the bone named costa, that it should always hold attached to the vertebral form posteriorly, and to the sternal form anteriorly. And why, therefore, not extend the name costa to those\nFig. 473.\nosseous parts which do not present greater varieties compared to ribs, than ribs do when compared to each other. The law of serial","page":648},{"file":"p0649.txt","language":"en","ocr_en":"SKELETON.\t649\norder must indicate the true character of those (4), hold series with the marsupial bone (6), osseous parts, whose various names serve to just as this latter holds series with the ribs blind us to the actuality of their homologous (7, 8.) Does not this serial order prove the caste. Examine closely the anatomical fact, identity of all these bodies in common ? Do and see whether I am stretching the imagina- they not all alike abut against their sym-tive faculty while I assert that the pubic (5,7) metrical fellows at the common median line ? and ischiadic bones (6, 8) of the bird {fig. 473. Does not the pubic bone exactly correspond ostrich) are actually springing from the lumbar with the sternal median line ? vertebr\u00e6 like true ribs, (1. of the thorax). If, In fig. 475., representingthe continuous therefore, it be the rule to affirm as incontest- series of costiform bodies from the clavicles\nible truth that these pubic and ischiadic bones of the bird are counterparts of the bones so named in the mammal, wherefore should we stop here, and hesitate to name both orders of bones (those of the mammal as well as of the bird) as ribs originally ?\nEven up to the present hour we find the osteologist strolling the Museum, and still marvelling at the interrogative marsupial bone (6, fig. 474.). \"What is it ? Whence is\nFig. 474.\nThe thoracic and ventral median line of the Orni-thorhynchus,\nShowing the serial homology between the coracoid hones (2), clavicles (1), ribs (3), and the marsupial (6) and pubic bones (5).\nit ? What is its interpretation ? What else, I answer, can it be, but a ventral rib, proper to some one of the lumbar vertebr\u00e6 behind. If in these pages I have furnished the querist with the idea that a lumbar vertebra has lost costo-sternal quantity, then he cannot be unproductive of the idea, that this marsupial bone, which now occupies the place of this costal quantity of the lumbar vertebra, is none other than this quantity itself. Besides this, it is also evident, from the serial order which the marsupial bone (6, fig. 474.) holds with the line of cost\u00e6 (3, 8, 7), that it is itself costiform.\nNow, in fig. 474., it will be also seen that the pubic bone (5), and the ischiadic bone\nFig. 475\nThe thoracic and ventral median line of the Crocodile {dorsal aspect),\nShowing the same serial order of the parts named in fig. 474.\n(1) to the ischiadic bones (4), it is scarcely possible to recognise a difference between all forms of this serial order. The clavicles (1) are succeeded by the ribs (2, 3, 8), these by the ventral ribs from (8 to 6), and these by the pubic bone (5), and the ischiadic bone (4). The homology between the bodies, (1) the clavicle, and (2) the rib, is as clearly apparent as between (5) the pubic bone, and (4) the ischiadic bone. Moreover, the homology between (1 and 2), (5 and 4), is as clearly apparent as between any two ribs of the series. If (5) the pubic bone still held its original place at (7), and had not disconnected itself from the ischiadic bone (4), it","page":649},{"file":"p0650.txt","language":"en","ocr_en":"650\tSKELETON.\nwould not be more like the clavicle (1) than it is in its present situation.\nIn fig. 476., the pubic bone (2) occurs opposite to the sacral vertebral lib (1), and the\nFig. 476.\nThe sacral vertebr\u0153 and pubic forms of the Crocodiles forming the whole quantity.\nwhole form is thereby completed as the sterno-costo-vertebral-archetypal quantity. The part 2, of fig. 476., may, therefore, as appropriately be termed a pubic rib as a costiform pubis. This pubic bone {2, fig. 476.) is separated from the sacral rib by an interval equal to the iliac bone, and this latter is regarded by a high authority * to be of costiform character ; but in the present reading I have no need to view the bone in this regard.\nProp. XXXVI. Chevron bones and ribs are identical parts of the costo-vertebral whole quantities or archetypes. \u2014 As every part which shall appear plus upon a cervical or lumbar vertebra, such as cervical or lumbar ribs, may be referred to the original whole quantities from which the cervical or lumbar vertebrae have been metamorphosed, and gain their proper interpretation accordingly, so may those parts which now and then appear plus upon the caudal vertebrae, such as \u201c chevron bones\u201d (4, of fig. 477.), be likewise referred to the original whole quantities from which those caudal vertebrae have been degraded. We have seen reason to interpret the caudal bone as the centrum of the vertebra, \u2014 of which vertebra ? Of the thoracic plus vertebra ; for why not of this plus archetypal form, as well as of any other form less in quantity than this archetype? If the caudal bone be considered as a part degraded from the equal of the lum-\n* The author of the \u201c Homologies \u201d entertains the opinion that the iliac bones are the \u201cpleurapo-physeal\u201d (costal) elements of the sacral vertebra, and thereby he connects the pubic arches (his h\u00e6-mapophyses) with their proper vertebral pieces in the sacrum. This opinion as to the costiform character of the ilium or haunch bone, is by no means that which I hold respecting it, nor can I believe that any other anatomist will discover the similitude between an iliac bone and a rib, any more than between a scapula and a rib, or any more than they will find to exist between a sternal piece and a spinal vertebral form, even though the imposing names of Oken, Meckel, and De Blainville introduce this latter opinion.\nbar vertebra, why not also from the equal of the thoracic costo-vertebral archetype ? If the caudal bone gives evidence of the fact that its present condition is owing to the loss of the\nFig. 477.\nThe caudal vertebra of the Dugong,\nShowing that it is not the typical or whole vertebral quantity.\nneural arch, the spinous process, and transverse-costal processes, and if it elicits accordingly the interpretation that had those elemental quantities still persisted, that which is now the caudal would have been equal to the lumbar vertebra ; so, on the like grounds, we may elevate ourselves to the reading, that if the thoracic ribs and sternum, the neural arch and spine still persisted, that which is now the caudal bone would have been equal to the thoracic archetype. Such a reading I here venture to put forth respecting the caudal bones {fig. 477.), and when these develope the chevron ossicles (4), I interpret them as being proximal parts of the costal arch (1, 2, 3), left standing after the degradation of the whole archetypal quantities. If a thoracic costo-vertebral archetype, such as fig. 478., whose costal\nFig. 478.\nThe caudal vertebra of the Dugong,\nShowing how the costal quantities are metamorphosed into the chevron bones.\narch is 1, 2, 3, undergoes such an amount of degradation as to sternal and costal quantity, that the proximal or vertebral ends (2) of the ribs (2,3) alone remain persistent; and if these ends (2, 3) of the ribs, while remaining still articularly appended to the vertebrae, are bent towards each other and to the median line, taking the place of the parts 4, 5, then","page":650},{"file":"p0651.txt","language":"en","ocr_en":"SKELETON.\n651\nwe shall have produced such a vertebra as fig. 477. or 478., which, composed of the elements 1, 4,5, happens in the tail of cetaceans, saurians, fishes, and many species of even the quadruped mammalia. There are chevron ossicles developed on the caudal vertebrae of the quadrumanous species. The caudal vertebra (\u00dfg. 477.) having the chevron bones (4) and inferior spinous process (5) appended to it, is taken to be the typical vertebra by all anatomists. They regard it as containing all the elemental parts proper to all vertebrae, an\nFig.\nopinion, the error of which I shall not here stay to point out, if it be not already demonstrated by what 1 have elsewhere spoken. Taken as quantities of osseous form, it would be as impossible to distinguish the same parts in such a \u201c typical \u201d vertebra, as either 9, 10, or 11, fig. 479., and that which stands at the thoracic region of spinal series, as it would be to read the quantity a \u2014 b and a+b as equal. In fig. 479., which represents the cetacean loins, it will be seen that the thoracic ribs 1, 2, 3, hold serial order\n479.\nThe lumbar region of the Dugong''s skeleton,\nShowing a serial degradation of the ribs into the chevron bones.\nwith the costiform pubic arch 7, and that this series is continued into the lesser quantities of chevron bones 9, 10, 1J. This serial order indicates the homology of these several structures.\nProp. XXXVII. The sternal median line ranges from the maxilla to the pubic bones of the abstract archetypal skeletal fabric. \u2014 In order to comprehend the truth of this proposition, the reader will have to exercise his mental as well as his bodily vision. He will have to expand his view over a large number of facts, and to compare these one with another, and sum together all the evidences, making them demonstrate the generalization which I here propose to establish. The abstract idea which general comparison has furnished me with respecting the sternal median series of osseous pieces, I shall endeavour to develope in the reader\u2019s mind, after the same manner in which it was furnished to my own ; and comparison of anatomical facts shall be my instrument.\nWhen I compare all skeletal fabrics by the sternal apparatus, I find that such an infinite variety marks them in respect to this particular, that it would take a long and busy lifetime to make a record of one half of those varieties ; and, after all, it is most true, that such record would not be worth one jot to science, since it would leave us in the end no better informed as to the law producing this variety, than when we first began. The one great fact which I shall remark upon in reference to the sternal apparatus is,\nthat it is a part which varies not only in several species but even in the one species, and that it is a structure the most indeterminate and indefinable of all those constituting the osseous skeleton. It is produced of variable lengths in the human body, and in every other animal species regarded per se.\nNow, assuming that the interpretation of sternal variety, and not the enumeration of it, is the sovereign and paramount object of comparative research, I here venture to affirm, that there is no other mode of accounting for this variety, as it appears already created, or of interpreting the process which has yielded it, excepting that of regarding every variety of sternal apparatus as being proportional lengths cut from a whole linear sternal quantity, drawn in continuous order through the median line of the fore aspect of the animal fabric from end to end. The reasons which lead me to adopt this reading of the source of sternal variety are as follow.\nWhen I examine the human skeleton as a form isolated from all other forms of the four higher classes of animals, I find the sternal series of osseous pieces extending through that region of the median line in front where the fully produced ribs meet it and enclose thoracic space completely. This costo-sternal junction happens generally between the seven first ribs and the sternal apparatus. It is owing to this sternal union of these seven ribs, that the human anatomist terms them \u201c true ribs.\u201d The five succeeding costal pairs he terms \u201c false ribs,\u201d because they are","page":651},{"file":"p0652.txt","language":"en","ocr_en":"SKELETON.\n652\nasternal, that is to say, falling short of sternal junction. A comparison held between these seven sternal and five asternal ribs, must lead the reason to draw the conclusion that the difference between both orders of these ribs is caused by the subtraction of a certain osseous quantity from the asternal ribs, which circumstance has dissevered them from the sternal median line ; and hence follows the relationary inference, that if this osseous quantity had not suffered subtraction or metamorphosis from those ribs which are now in asternal character, these would have persisted in their original archetypal or plus quantities, and would thereby have joined a sternal median line, just in the same way as the seven true ribs still do. In this case, we should have had twelve true or sternal ribs forming the human thoracic cavity. In the same way, again, I may remark, that if the five ribs which are now lost to the lumbar vertebrae, and which loss has rendered these bodies in the lumbar fashion, had still persisted in their original archetypal proportions, these ribs would also have joined a sternal median line, and would have thereby completely enclosed ventral space. In such case we should have had seventeen true or sternal ribs. Again, if the original or archetypal costo-vertebral osseous quantities, from which the sacro-caudal series of vertebrae have been metamorphosed, had still persisted, these also should have joined a sternal median line, and completely enclosed space. In this case we should have had twenty-eight true or sternal ribs. And if the original archetypal osseous quantities, from which the seven cervical vertebrae have been metamorphosed, had also still persisted, we should then have had thirty-five true or sternal ribs. In which case the human skeletal axis, instead of numbering, as it does, thirty-five spinal segments of variable proportions, such as those of cervix, thorax, loins, sacrum, and caudex, would have presented to us, in its original or archetypal quantity, the number of thirty-five sternal costovertebral spinal segments. In such a form, I imagine that the sternal median line would range from one extremity to the other of the serial spinal axis. And now let us examine, whether this ideal archetype coincides with all natural evidence derivable from general comparison.\nNot only does a numerical variation occur in human species as to the true or sternal ribs (for I have seen them counting from 7 to 10), but I will venture to predict, that we should find this numerical variation, as to sternal ribs, happening amongst the individuals of any other species of the four classes, if we dissected them as frequently, and with as much interest, as we do the human body. In the human skeletal form, we are accustomed to name the seven sternal ribs as normal to this type ; and all excess of costo-sternal union as abnormal or anomalous. The like variation, from normal to abnormal, occurs amongst the individuals of every known species of skeleton ; and the reason which I\nassign for this variety of infinite account is, that all such variety, whether normal or abnormal, is but a minus condition, degraded from a plus or archetype condition of skeletal form, which latter has all the vertebral pieces holding homologous series behind, all the costal pieces holding homologous series laterally, and all the sternal pieces holding their own order anteriorly. In such an archetypal skeleton there could be no such hiatuses or gaps, in series, as those of the cervix and the venter, &c., where, be it remembered, all variety and \u201c anomalous\u201d creation occurs.\nNow is there not every good reason to believe that the contrast, which the normal condition of any one species bears to the abnormal condition ofthat same species in respect to the number of ribs meeting at a sternal median line, is only a part of that general contrastive condition which all species bear to one another, in respect to this same costo-sternal union or non-union ? Let us examine this truly marvellous law, whereby all contrasts of formation result, not only for the one species, but for all species : for it is this law which I conceive to be the proper aim of the osteologist. Let us not weary patience with recounting the facts that skeletal forms do differ, but let us rather furnish imagination with the one over-arching fact, as to how they are differenced, each one to each, and all to archetypal uniformity.\nAll individuals of one species will, when viewed collectively, manifest the normal and abnormal contrasts to that same species, in respect to variation in the number of sternal, and the number of asternal ribs. All species, viewed collectively, will manifest the same, only in a greater degree, and in broader contrast. When I compare the normal and the abnormal conditions of costo-sternal union in individuals of the same species, and also the numerical variety as to the number of sternal and asternal ribs, I find that the abnormal is to the normal condition of the one species, nothing more than what the normal condition of one species is to the normal condition of another ; hence, I say that it is the same law which produces, in the one case, the normal and abnormal castes of form in the one species, and the normal castes of form in diverse species. If one human skeleton differs from another, as to the number of sternal ribs and of asternal ribs, and that in one we find the cervical ribs, in another the lumbar ribs, and in all some number of ribs or other, what is this variety, and whence has it occurred, but by the operation of that same law of metamorphosis which fashions the skeletal axis of a baboon of one number of ribs, that of a horse of another number, that of a sloth of another number, that of a cetacean of another number, that of a bird of another number, that of a reptile of another number, that of a fish of another number ? Is it not this same law which has fashioned all individual species of mammals of variable numbers of ribs ? all individual species of birds of variable numbers of ribs ? all individual species of reptiles of","page":652},{"file":"p0653.txt","language":"en","ocr_en":"SKELETON.\n653\nvariable numbers of ribs ? all individual species of fishes of variable numbers of ribs also ? Is not numerical difference, as to costal, as to vertebral, and as to sternal elements, infinite? Where, then, shall we find a resting place in this ever moving creativeness of the variety ? There is no resting place for the understanding, except in the idea of the skeletal archetypal uniformity, and there is no other mode whereby to mount to the recognition of this archetype, but by summing together all proportional variety, and constructing plus uniformity from out of it.\nThe number of osseous thoracic sternal pieces varies even in the same species ; it varies still more in the different species of a class, and general comparison carried through the four classes will prove incontestibly, that the region which is ventral, or minus the osseous ribs and sternum, in one animal (the human), is furnished with the ribs and sternum in another animal (the saurian), and hence becomes thoracic for this latter animal. In the mammal venter, the costo-sternal osseous pieces do not exist, but in the saurian venter they do. In the same way will general comparison prove that the region which is cervical, or minus the ribs and sternum, in one animal, is furnished with the ribs and sternum in another animal, and hence becomes thoracic for this latter animal. In the mammal cervix, the costo-sternal osseous pieces do not exist as such, but in the ophidian and the fish they do ; for what else is the fish\u2019s hyoid apparatus but a series of ribs joining a sternal series ?\nNow, the true interpretation of the individual skeletal fabric is only to be had in the abstract or compound idea which springs from general comparison. The abstract or archetypal skeleton is the exponent of the special or individual skeletal fabric. The former is plus quantity, the latter is a special creation degraded from such a plus.\nThe thoracic sternal series of the human skeleton commences, as bone, at the junction of the first pair of thoracic ribs, and continues as bone as far as the junction of the seventh pair of ribs ; after this latter point the human sternum degenerates into cartilaginous or primordial tissue of the second stage of ossifie process, and from thence it is continued over the ventral region in fibrous or primordial tissue of the first stage of ossification, and as such is united to the pubic symphysis, thus relating this point to the thoracic sternum, and also the pubic and ischiadic bones to the thoracic ribs, with which they are identical, no doubt. Those fibrous bands, named \u201c line\u00e6 transvers\u00e6\u201d of the human venter, must be taken as sketches drawn in primordial substance by the hand of nature, indicative of the ribs which are wanting at this region of series. Those ribs are proper to the lumbar vertebrae. The linea alba is a sternal trace of archetypal osseous quantity, and is proper to the ribs which are now wanting at the mammal venter. The saurian venter, furnished as it is with both sternum and ribs, and lumbar vertebrae, must therefore be regarded as a nearer ap-\nproach to archetypal or thoracic uniformity than the mammal venter. In the former, the ventral region is embraced with an osseous costo-vertebral sternal apparatus, like the thorax. In the latter, the ventral region presents this apparatus degenerated into primordial or fibrous bands. The original of the mammal venter is thoracic, and, as such, I affirm that this original, although now only in idea, stands before the mental vision in as vivid a character as if its actual presence presented to the corporal vision. That which is wanting at the venter of the mammal is equal to that which is persistent at the venter of the saurian ; and thus, in idea, I draw the sternal and costal osseous series over the ventral region of the mammal body. In every skeletal fabric where a venter is formed without the sternum and the ribs, nature may be said to have subtracted these for fitness and functional ease.\nThe law of species requires that the costo-sternal series should not persist in the ventral and cervical regions of all animals, the reasons for which are obvious. It is by this law' of special or proportional variety, which creates the cervix and the venter as fitting hiatuses in series, that the law of archetypal uniformity becomes eternally interrupted. The law of species is acting in constant nisus opposed to the law7 of plus quantitative uniformity. Both laws are eternal, and their eternal acts yield forms as they are. viz. a unity in variety ; that is to say, a whole quantity undergoing a metamorphosis of parts. It is this metamorphosis or subtraction of parts proper to the whole archetypal quantity, which furnishes all the endless sum of variety.\nThe \u201c xyphoid \u201d cartilage and the \u201c manubrium sterni \u201d are the opposite extremities of sternal series in the mammal skeleton. At these extremities there is manifested, as it w'ere, a constant tension or endeavour to extend the sternal line over the neck and abdomen. In the mammal body and others, this tendency to extend is held in constant subjection ; but occasionally we find that this nisus of the creative force advances a step, and marks its progress by the development of \u201c episternal ossicles \u201d at one end of the sternal line, and by additional nuclei of osseous substance at the other end. The character of either extremity of the sternal series is unfinished ; and even amongst the individuals of the several species of mammalia and birds, it cannot be said to be fixed. Sternal creation, and the law of its infinite variety as to length, can only be fully ascertained by extending the observation through general comparison. In general comparison, we readily discern the ability of creative force exercising itself by the simple addition and subtraction of certain known elemental parts. By the addition of parts, nature mounts to archetypal uniformity ; by the subtraction of parts she degrades to variety. Every variety is but a submultiple of archetypal uniformity.\nWhen I limit my observation to the individual mammal skeletal form, I find the","page":653},{"file":"p0654.txt","language":"en","ocr_en":"654\nSKELETON.\nFig. 480.\nAn archetypal skeletal axis, constructed of the Piscean cervix, the Mammalian thorax, and the Reptilian venter and caudex,\nShowing the original serial continuity of the ribs and sternal median line.\nosseous sternal median line produced for the most part of set dimensions ; but when I extend my comparison through all individuals of that class, I find the sternum to be created of variable length, and constituted of variable numbers of elemental pieces. When, further, I carry my observations through all individuals of the four classes, fishes, reptiles, birds, and mammals, I find that the osseous sternal median line has no limit short of the space which the maxillae mark before, and the pubic arches behind. Hence it is that I call every sternal apparatus, which happens to be created of lesser dimensions than this space, as a specialty cut from the transcendent line of sternal median uniformity, such as ,/?g.480. represents, with the piscean neck ab, the mammal thorax c d, and the reptilian venter and loins e f. Now, the hyoid apparatus (a,b,c,d) occurs at the median line of the cervix (a b, fig. 480) where we know costal quantity to be subtracted. The costo-sternal apparatus (a,b,c,d) happens at the median line of the thorax (c d), where we still view costal quantity persisting. Let these two facts be submitted to the focal light of comparison, and I doubt not but tfiat reason must draw the conclusion, that as the ventral sternum (fc k) relates the pubic symphysis (c* d) to the thoracic sternum\ti), so\ndoes the hyoid sternum as a cervical sternum (g, h) relate the maxillary symphysis to the thoracic sternum (i, i). Hyoid apparatus is, therefore, but a name by which we designate the degree of metamorphosis to which the original costo-sternal series of a cervix has been subjected. It is this metamorphosis which has rendered the costo-sternal quantities, proper to the cervical vertebrae, into the vocal organs of one class of animals, into the laryngeal organs of all animals, and into the branchial organs of the fish (a b), in which latter class the character of the original costo-sternal apparatus is least modified ; for evidently the hyoid or branchial apparatus (a, b, c, d) of the fish (a b) is constituted like the thoracic apparatus ([a,b,c, d) of other animals (c d), of a series of ribs joining a sternal median line.\nThe greater the degree of metamorphosis which the archetype has undergone, the greater is the obscurity of that structural analogy existing between organs of the same order in two or more animals.\nBut though we are accustomed to limit the name sternum as applicable alone to the osseous part of the common and general median line of the mammalian animal, and though we do not usually recognise as a sternum in this class that region of the median line which presents in cartilaginous structure, as, for example, at the neck and venter, still I maintain that, so long as it is acknowledged that comparison is the only instrument by which we can ever hope to ascertain the law of formation in the creation of special differences, we must interpret the linea alba as being the continuation of the sternal line in the mammal abdomen, and the cricoid, the thyroid, and","page":654},{"file":"p0655.txt","language":"en","ocr_en":"SKELETON.\n655\nhyoid forms, whether these be cartilaginous or osseous, as being the continuation of the sternal median line in the mammal neck.\nThe history of the ossifie process teaches us that every part of the skeleton which presents now in osseous structure, has passed through the prior stages of cartilage and of fibrous or cellular primordium. The general median line in front of the mammal form presents, in regional divisions, the one differenced from the other only in respect to these three stages of the ossifie process. The thoracic sternal median division presents in the tertiary or osseous stage. The cervical sternal median division of this same line presents in cartilaginous or secondary stage. The ventral sternal median division of this same continuous line presents in the fibrous or primary stage. But whether the several divisions of this one sternal median line be, in the mammal body, of fibrous, or cartilaginous, or osseous tissue, it must still be regarded as the same unbroken sternal series from maxilla to pubis. The only difference which marks one class or species of skeletal form as distinct from another throughout the animal kingdom, is simply the same as that which marks one region of the sternal line in one form diverse, or special, to another region of the same line in the same form. What the ventral or the cervical sternal median line is to the thoracic of the same animal, namely phasially different ; just so is the ventral and the cervical median line of the several classes and species of animals diverse to the thoracic of all animals by a simple arrest of development in one or other of the three phases of the ossifie process. The venter of a mammal is intersected with fibrous traces of the sternum and ribs. This sternum and these ribs are of osseous growth in the saurian venter (k, k, fig. 480.). The cervix of a mammal is intersected with the cartilaginous and osseous traces of original sternum and ribs, and these traces of the sternum and ribs are now called hyoid apparatus. The homologue of this hyoid apparatus, which is fashioned by the metamorphosis of sternum and ribs, is presented in the osseous fish (g,fig. 480.) as a sternum and ribs, to which we give the name hyoid apparatus.\nWhen I compare the foregoing anatomical facts together, I conclude that the abstract or archetypal skeletal fabric (fig. 480.) to which comparison gives creation in my mind, is a form whose median sternal line is continuous from maxilla to pubis, from g to /, and in this archetype the ribs (a b) are holding continuous series. The vertebrae (a b, c d, e f) hold serial order in the same archetype also. The ribs succeed the hyoid apparatus, the pubic and ischiatic bones (<?#<?#) succeed the ribs, and the chevron bones (b*b*) succeed the pubic bones. This serial order demonstrates the homological cast of all these parts, and therefore I have numbered them alike. When these serial parts are taken in connection with the vertebrae behind, they constitute the archetypal series of whole quantities.\nProp. XXXVIII. Every fossil skeletal species of extinct animals, as well as every recent existing species of skeleton, are forms created of the archetypal skeleton. \u2014 While we understand clearly, that it is the graduated metamorphosis of certain parts from one or many of the serial sterno-costo vertebral archetypes which yields all spinal axes, variable as to the numerical lengths of a cervical, or a lumbar, a sacral or a caudal region, and while we know, even to a demonstration, that the thoracic region results simply by the persistence of some of those archetypes, then we can readily understand that the persistence of all the archetypal quantities would leave the form devoid of any such regional spinal variety as a neck, a loins or a caudex. And when I add to this remark this other, namely, that all the archetypes undergoing cervical metamorphosis would render all the spinal length in cervical character, or, if undergoing lumber metamorphosis, would strike the whole spinal length in lumbar character, or if submitted to sacral or caudal metamorphosis would leave the whole spinal length of sacral or caudal stamp, then 1 see no reason why anatomical science should marvel at the length of a pl\u00e9siosaure neck as an extraordinary fact \u201c dug out of the bowels of the harmless earth,\u201d however bizarre a creation this skeletal form may seem to the wonder-working geological speculator.\nForms, as they are at present existing, and congeneric, seem to me to manifest, under contrast, no less a cause for wonder while I view them comparatively, than these same existing species of form can give rise to when I regard them comparatively with those of the lost or extinct species of a foregone time. But I believe that the only hope which science can ever entertain of solving the problem of formation in the past, must depend upon the demonstration of the process of the creative force, which rules formation in the present And when we shall have clearly demonstrated the creative law which at present strikes out the form of an ostrich in presence of the form of a whale, then we will cease to regard with doubtful interrogative the form of the Pl\u00e9siosaure laid side by side with the Ichthyo-saure, or any other figure the vestige of foregone creation. When science shall arm herself cap-a-pie with the knowledge of a law, then will she be enabled to contemplate the past, the present, and the future, holding her statuesque gravity still unmoved, however or by whatever show of seeming bizarre facts short-sighted ignorance may strive to startle her.\nUpon the proof of the truth of the reading here advanced, viz. that the cervical the lumbar, sacral, and caudal spinal regions consist of spinal segments metamorphosed or degraded from such archetypal segments as we find standing for the thoracic spinal region of all skeletons, depends the full and just interpretation of all varieties of spinal axes of animals, whether now existing or now extinct.\nProp. XXXIX. The craniofacial apparatus consists, like the thoracic apparatus, of","page":655},{"file":"p0656.txt","language":"en","ocr_en":"656\nSKELETON.\nvariable proportionals of the sterno-costo-verte-bral quantities. \u2014 The connection which exists between the cranial and the facial structures is quite as intimate as the connection which exists between dorsal vertebrae and thoracic ribs. In nature, we never find the cranial structures happening independent of the facial apparatus ; but we invariably witness the presence of both, whenever the presence of one is manifested, just as is the case with dorsal vertebrae and the costal apparatus; and therefore it is that when I shall presently draw comparison between cephalic and thoracic regions of the spinal serial axis, I shall regard the one as a cranio-facial series of osseous quantities, homologous to the other as a costo-vertebral series.\nBefore I proceed to compare the craniofacial apparatus with the thoracic costo- vertebral apparatus, let me here distinctly state one or two positions, which I shall not engage to define, simply because it would be impossible to prove that certain conditions were manifested, which are in fact and nature not manifest. Firstly, 1 do not mean to shew that an equality or quantitative uniformity characterises the cephalic and the thoracic regions of the one spinal series ; nor, secondly, that all species of cephalic apparatus of the four classes are constituted of absolutely equal quantitative structure*, any more than thoracic apparatus are themselves ; nor, thirdly, that the number of cranio-facial segments and the number of costo-vertebral segments correspond in the same spinal axis ; nor, fourthly, that the number of cranio-facial segments correspond in the cephalic apparatus of all animals of the four classes, any more than the thoracic apparatus of the same animals correspond as to the number of spinal costo-vertebral segments.\nThe so-called \u201cvertebral theory\u2019\u2019appears to me to have played lightly with the serious patience of anatomical science, and to have brought itself into discredit, not because it has proved no one truth in generalisation at all, but because it has striven, while standing upon equivocal and unproven grounds, to demonstrate that which had existence no where save in the imagination. An ill-defined sha \u2022 dowy resemblance was first seen to have existence between cranial and spinal vertebral forms, and in pursuance of this idea has arisen all that vagrant and bizarre imagery\n* Almost all the anatomists of the French and German schools differ in opinion as to the number of modified vertebrae which compose the head, for while some of them limit the number to three, viz. those which enclose the encephalon, others count as many as seven ; and these latter have increased the number by absurdly likening the facial structures to the vertebral forms also. Goethe counts six, three of which comprise the cranium, the other three the face. Oken enumerates four ; Spix, three; Cuvier, three ; Geoffroy, seven ; Carus, three (Lehrbuch der Zootomie) ; Meckel, three (Beitr\u00e4ge zur vergleichenden Anatomie, Band II. S. 74.) ; Bojanus admits four, and Burdach only three. Professor Owen enumerates four in the fish, the reptile, the bird, and the mammal. See \u201c Homologies,\u201d &c.\nwhich has enveloped the first dawn of a great truth in the smoke and mist of that sacrifice and homage which it was thought was due to the inspired genius of him* who first promulgated it. I shall not here trouble either the reader or myself with a barren discussion about the merits or demerits of the views of those authors who sought to expand this vertebral theory beyond its natural limits, or of those who strove to discountenance the theory altogether, rather than to pursue it to the verge of sheer nonsense. My present limits confine me to the observation of nature, and will not suffer me to canvass written opinion concerning her to any greater extent than such opinion shall be confirmed as corresponding witn natural truth. Out of all that loose and flighty imagery which anatomists of the transcendental school have indulged in, I select the first and only truth which has ever been fairly established, viz. that one respecting the homology between cranial and vertebral structures. That this homology exists between the osseous envelope of the cerebral mass and the osseous coverings of the spinal chord, is now a fixed and immoveable fact in anatomical science. But though the existence of this homology is now undeniable, still I may remark that every observation which serves to prove something further in respect to spinal vertebrae, which had not been known previously to the recognition of this cranio-spinal resemblance, must also prove that the same thing was unknown respecting cranial vertebrae. Every new fact, established upon the comparison of spinal vertebrae, must be new also in regard to cranial vertebrae ; and this is the\n* Oken is generally acknowledged as the signal discoverer of the homology between cranial and spinal segments. He believed that the cranial structures were repetitions of the osseous quantities proper to the cervical vertebr\u00e6. It is said by some anatomists with Meckel, that Frank first recognised this analogy between the skull and the vertebr\u00e6 (Sammlung Auserlesener Abhandlungen, Band XV. S. 267.). Burdin supposed the head to be a complicated vertebra (Cours d\u2019Etudes M\u00e9dicales, Paris, 1803, vol. i. p. 16.). Keilmeyer believed the same. Next Geoffroy St. Hilaire, Dumeril, and Goethe extended the theory, making such observations as are at present considered to be purely hypothetical, and little better than fanciful vagaries which almost overshadow the first truth. The similitude drawn by Goethe between the facial bones and the vertebr\u00e6, is scarcely less absurd than the likeness which Oken and Spix are supposed to have seen between the temporal styloid process and the sacrum, or between the hyoid apparatus and the pelvis. Hence, it is not to be wondered at why Cuvier mocked the cranial vertebral theory, when we find Spix seeking for a repetition of the' regions of the trunk of the body in the head; and, because he would bend nature to his wild unstable fancy, whether she were willing or otherwise, so we have him representing the pelvis in the temporal bone ; and likening the hind limbs to the lower maxilla ; the auditory ossicles to the pubis ; the maxillary condyle to the femur; the coronoid process to the tibia, &c. &c. See Cephalogenesis, seu Capitis ossei Structura. For Oken\u2019s views of this subject, see Isis, 1820, No. 6. p. 552. ; Esquisse d\u2019un Systeme d\u2019Anatomie de Physiol. &c., Paris, 1821, p. 41. ; also Ueber die Bedeutung der Schadelknochen, Jena, 1817.","page":656},{"file":"p0657.txt","language":"en","ocr_en":"657\nSKELETON.\npoint to which I direct the reader\u2019s attention, for it is upon this assertion that I found the present reading. If, for example, from foregoing remarks I have proved that the spinal vertebra is not a whole quantity, as it exists either in the cervical lumbar sacral or caudal regions, but that it is in reality a proportional metamorphosed from the sterno-costo-verte-bral archetype, then it must follow that the figure which has been named cranial vertebra is also a proportional metamorphosed from the like archetype; for that which is true of the form we name spinal vertebra, must unquestionably be true of the cranial form, which we liken to a vertebra.\nNow, in each of those spinal forms which hold serial order from cranium to the other extreme, there exists, as I have already shown, some proportional of the rib. In the thoracic spinal segment, the rib is plus, and meets its fellow of the opposite side at the sternal piece. This thoracic costo-vertebral form 1 have named archetype, and compared with it I have shown that all other spinal vertebrae vary from it, not because of the introduction of any new elemental part found in any of them, and not found in the archetype, but simply because they are, compared with this archetypal or plus quantity, the minus proportionals of such plus archetypes. However, it is still most true that the quantity which we recognise as the cervical lumbar or sacral vertebra, does contain within itself the rudiment of the rib, and therefore I repeat that this rib makes an integral part of all vertebrae \u2014 of all those, at least, which possess a certain quantitative character.\nIt must have already appeared evident to the reader that it was premature to have sought to establish an identity between cranial and spinal segments, without having first ascertained the quantitative nature of the thing which was named vertebra. For as it was evident that something was yet to be proved by the comparison of spinal vertebras, so therefore it was not possible to prove all that might be known of cranial vertebrae, while prematurely referring one unknown quantity to another equally unknown \u2014 I mean the spinal vertebra to the cranial vertebra. Since it was by no means as yet demonstrated that the form which anatomists recognised as the spinal vertebra was a quantity of fixed and invariable character, how then could it be proved that the form to which it was likened in the cranium was of fixed and unvarying dimensions ?\nWhen anatomical science, lighted by the torch of Oken\u2019s genius, first pierced the mist and obscuring cloud of nomenclature, which described the cranial structures as distinct from the spinal forms, and when it expounded the facts and doctrine of that radical homology of caste which related both classes of structure together under the common name vertebrae, it did not in truth progress much nearer to the explanation of the law of form than when it first explained, despite of nomenclature, the analogy which existed between\nVOL. IV.\nsacral bones and lumbar vertebrae. In the one case it only related hitherto unknown forms to vertebrae, without knowing the typical form of vertebrae themselves ; in the other case it related the sacrum (sacer) to the lumbar vertebrae, and called both vertebrae, without having any idea of the vertebral archetype or whole quantity.\nThe facial apparatus is to the cranial forms just what the thoracic costae are to the dorsal vertebrae, namely, the integral parts of whole sacral quantities.* As in thoracic series, it is required that we should take the dorsal vertebra, holding its natural connection with the thoracic rib, and describe both as the parts of whole thoracic quantities; so in cephalic series, we are reminded, from the natural connection which facial structures hold with cranial forms, to describe both orders of parts as constituting the whole cephalic quantities. It is upon this connection apparent between facial and cranial structures at one region of series, and between vertebral and costal structures at another region of the same serial order, that I am induced to draw a likeness or resemblance, as well between costal forms and maxillary forms, as other anatomists have recognised between cranial forms and spinal vertebr\u00e6. The identity which is already proved to exist between the latter must prove the identity of the former likewise. The homology of caste which \u00e0 priori reasoning establishes between cranial and spinal forms, will lead us to interpret by a posteriori reasoning that an homology of caste must characterise the costal and the maxillary forms ; for if we are already forced to acknowledge identity between cranial and spinal vertebr\u00e6, so must we, I contend, be induced to name the maxillae of cranial vertebr\u00e6 to be the homologues of the cost\u00e6 of spinal vertebr\u00e6 (even if special modification had rendered homology still more obscure than it is at present), and for this reason, viz. that cost\u00e6 are the natural attendants upon vertebr\u00e6, wherever we find vertebr\u00e6, whether in the head or in the spinal serial axis.\nAs all spinal segments whatever contain some proportional of a rib, it must follow that the rib is to indicate the presence of the vertebral piece as much as the vertebral piece implies the presence of the rib ; and if the cranial forms are proved to manifest a structural identity with spinal vertebr\u00e6, while we see that the latter are always attended with\n* If the facial he to the cranial structures just what the thoracic cost\u00e6 are to the dorsal vertebr\u00e6, then it will appear evident to the reader that, when Oken, or Spix, or Goethe, or Geoffroy likened the facial structures to vertebr\u00e6, they committed an error as evident as if they saw an analogy of form between the thoracic ribs and the vertebral pieces. Schultz (De Primordiis Systematis Ossium et de Evolutione Spin\u00e6 Dorsi in Animalibus) wak the first to pronounce the gross error into which the transcendental anatomists had fallen in respect to likening the facial apparatus to the vertebral pieces. Bojanus, in like manner, prudently freed himself from this error. Professor Owen considers the facial apparatus to consist of the \u201c inverted arches\u201d of the cranial vertebr\u00e6.\nu u","page":657},{"file":"p0658.txt","language":"en","ocr_en":"658\nSKELETON.\nthe ribs, then the cranial vertehr\u00e6, as verte- of cranial vertebrae, if these ribs be not the brae, must have the ribs also. What other maxillary arches ?*\ncephalic structures, therefore, are there in the\tNow there happens in fig. 481., between the\nhead which may be said to stand as the ribs costiform maxilla (dd*) and thoracic ribs\nFig. 481.\nThe human cranio-facial and cervico-hyoid apparatus,\nShowing that the hyoid apparatus relates to the cervical vertebrae, and the facial apparatus to the cranial vertebrae, just as the thoracic or costo-stemal apparatus relates to the dorsal vertebrae.\n(/>/>*), that hiatus or gap in costal series which is called the cervix, and it is this hiatus\n* In the \u201c Homologies,\u201d the author names the maxillae the \u201c inverted arches \u201d of the cranial vertebrae. These inverted arches answer to the h\u00e6ma-pophyses of the author\u2019s ideal typical vertebra, and not to the pleurapophysial elements (the ribsj of that ideal form. Now I confess, for my own part, that I do not see clearly why these maxillary arches are referred to the former rather than to the latter elements. There is evidently some mystery about this ideal typical vertebra figured in the \u201c Homologies,\u201d which I cannot penetrate, and for this reason, viz. that I find the author\u2019s \u201c ideal typical\n(q q q) which interrupts the idea of a continuous serial costal order ; at the same time\nvertebra,\u201d while compared to the osseous segment taken from the bird\u2019s thorax, and which he terms the \u201c natural typical vertebra,\u201d does not correspond quantitatively. In this ideal form I find the ribs (pleurapophyses) but as mere rudiments, whilst in the natural form I see that these ribs embrace thoracic space from the spine nearly to the sternum. Again, in the ideal form the h\u00e6mapophyses hang appended to the vertebral centrum ; whereas in the natural typical form they articulate with the distal ends of the thoracic ribs.","page":658},{"file":"p0659.txt","language":"en","ocr_en":"SKELETON.\nC59\nthat vertebral series (g, h, i, k, l, m, n) is still uninterrupted as it passes from dorsal vertebrae (p), through cervical vertebrae, to cranial vertebrae (f, e, d, c, b, a). Thus we find that vertebral series persists continuously, while costal series is interrupted by the cervical hiatus happening between the maxilla above and the thoracic costae below. This hiatus is caused by the degradation of costal quantity simply, for we still see that rudimentary ribs (g, h, i, k, l, m, n) are developed upon each of the cervical vertebrae. If the original plus ribs of the cervical vertebrae still persisted at the lines q q q, for them as the plus ribs (pp*) do for the dorsal vertebrae, then we should have the maxilla holding serial continuous order with the thoracic ribs, in which case it could scarcely be doubted that the maxillae were structural homologues of the costae elsewhere. But in this occurrence of cervical hiatus, which results by the metamorphosis of that plus costal quantity which I consider to be originally proper to the cervical vertebrae, we have the facial apparatus now disconnected from the thoracic apparatus ; and the only structural entity which at present relates the maxilla above to the costae below is the hyoid apparatus (/*, g*, h*, l*, &*). Hence this latter structure can come of no other source than cervical original costal quantity under metamorphosis.\nThe idea of the plus costal quantity, which we now know to be lost at the cervix, is equal to the idea of the same quantity present ; and hence, when I say that they are the plus ribs which are lost to cervical vertebrae, it is as strong an idea as if I still viewed them persisting at the lines q q q. If these cervical plus ribs still persisted, they would leave no doubt that the maxillae are of costal origin. Indeed the maxillae, as they at present stand, prove a much stronger resemblance to ribs than cranial vertebrae do to spinal vertebrae ; and if we see little reason to doubt the identity between the latter structures, there is, as it seems to me, even still less reason to doubt the homology or correspondence between the two former.\nIn fig. 481. I have indicated the number of those vertebral forms which constitute the human cranium, taking as my guide the invariable attendance of the costal structure upon the vertebral structure, as well in the head as in all other regions of the spinal axis. The first dorsal vertebra (p) is attended by the plus ribs (/>\u00a3>*), stretching over thoracic space from the back to the sternum. All the cervical vertebr\u00e6 (n, m, l, k, i, h, g) are likewise attended by the minus costae (n, m, l, kt i, h, g). From these severally I have produced lines to the hyoid apparatus, and these lines, together with the hyoid pieces, indicate thoracic costo-sternal quantity, which metamorphosis has degraded down to the quantities at present forming the cervical region. The intervals between the cervical lines of the original costae are marked (qq) as corresponding with the intercostal spaces.\nThe atlas (g) supports the occipital or first (reckoning from below) cranial vertebra. In the atlas vertebra* may be recognised (g) the vertebral end of its rib, which when produced through the line q joins g, the greater cornu of the hyoid bone, to which latter the body g* is attached ; this group of elementary parts represents the debris of the archetypal sterno-costo-vertebral quantity ; the atlas stands in series with the other vertebr\u00e6, while the inferior half of the hyoid bone holds series with the sternum. The axis vertebra (h), in the same way, corresponds to the (h*) thyroid cartilage. The third cervical vertebra (i) corresponds to the cricoid cartilage (i*). The fourth vertebra (k), the fifth (l), the sixth (m), point to the rings of the trachea. The seventh vertebra (n) stands opposite to the clavicle (n), which I regard as the costa of that vertebra.\nThe first or occipital costo-vertebral quantity of the head consists of (f) the centrum and the pieces V'\"'', 2, 3, which form the neural arch and spine. The rib and sternum or costo-sternal quantity of this vertebra is represented by the styloid process (/), which, when produced in a line to (/*) the upper half of the hyoid body with its lesser cornu, completes this group of elemental parts, j-\nThe second or petrosal costo-vertebral quantity of the head consists of (e) the centrum and the parts V\"\", 2, answering to the neural arch and spine ; the costo-sternal quantity of this vertebra is represented by the tympanic bone (e) coiled upon itself, and enclosing within its circle the auditory ossicles. The tympanic bone, together with the auditory ossicles, may be regarded as costo-sternal quantity, specially modified in subservience to the special sense of hearing.];\nThe third or temporal costo-vertebral quantity of the head has no part corresponding to the body at D ; but the neural arch and bicleft spine of this segment of the skull are represented by the parts l//r/, 2. The costo-sternal quantity of this vertebra is represented by the lower maxilla (d) articulating like a rib with the glenoid cavity (d). $\nThe fourth or post sphenoid-costo-vertebral quantity consists of (c) the centrum and the parts T\", 2, answering to the neural arch and spine. The costo-sternal quantity of this vertebra is represented by the zygoma (c, c) and upper maxilla (c*).\n* Professor Owen refers the clavicles to the atlas vertebra, and considers them as forming the haemal inverted arch of this vertebra. See \u201c Homologies,\u201d &c.\nt The scapulary limbs are referred by Professor Owen to his occipital vertebra, of which he considers the scapulae to be the ribs, and the rest of these members to represent what he terms the \u201c diverging appendages.\u201d\nX Professor Owen does not regard the petrous bone as a part of a cranial vertebra, but he calls it a \u201c sense capsule,\u201d and refers it to the splanchno skeleton.\n\u00a7 The styloid process is regarded by Professor Owen as the rib of his parietal vertebra.\nu u 2","page":659},{"file":"p0660.txt","language":"en","ocr_en":"660\nSKELETON.\nThe fifth or anterior sphenoid costo-verte-bral quantity consists of (b) the centrum and the part 1\", as the neural spine. The costo-sternal quantity of this vertebra is represented by ([b) the palate bone.\nThe sixth or ethmoidal costo-vertebral quantity of the head consists of (a) the centrum, with the part 1' as the neural arch. The costo-sternal quantity is represented by the nasal bones (a).\nNow, considering fig. 481. as a whole, I find it to be characterised in certain ways, which still further prove the nature of the fact, that the human head consists of six* costovertebral archetypes, as numbered above ; and though I by no means would have it understood that I consider each of those cranial archetypes to be equal in quantity either to one another or to the first sterno-costo-ver-tebral quantity of the thorax, still I find that there are certain sutural marks in the human head and facial apparatus, which seem to define, with sufficient clearness, those natural groups of bones which form the archetypal quantities. The spaces called intervertebral, amongst the spinal vertebrae, viz. those spaces which occur between the neural arches of two adjacent vertebrae, such as g and h, are represented by all the transverse sutures of the cranium. Those sutural intervertebral intervals I have marked thus : Between the axis h and the atlas g, the intervertebral space is o'\"\"\" ; between the atlas g and the occipital form, the space is o\"\"\" ; between the latter and petrous form is the lambdoidal suture o'\"\", and so on. The intercostal spaces are marked q, q, &c.\nWhen we seek to determine the nature of the sutures of the cranial structures by comparison with the serial vertebrae of spinal order, we should bear in mind the fact that one order of the cranial sutures must correspond to the intervertebral spaces of spinal vertebrae, while another order of cranial sutures must answer to those points where the elements constituting each vertebra join. Thus, whilst such sutures as the coronal {fig. 481. o',) and lambdoidal (o'\"\") answer to the intervertebral spaces (o'\"\"\"), the sutural temporo-parietal point of union between \\\"\" and 2 answers to the point of junction between the elements 1, 2 of the atlas vertebra G, or of the axis h. The frontal suture is that line of union which the symmetrical laminae of one vertebra ot the spine would, when meeting each other at the median line of neural space, represent. The sagittal suture is a biclevage of the spinous process (viz. the symmetrical parietal bones) of that vertebra of the head to which they belong.\nAs the nerves passing from the spinal cord bear a somewhat fixed relation to spinal ver-\n* Professor Owen enumerates four cranial verte-br\u00e6, viz. the occipital, parietal, frontal, and nasal. He regards the ethmoid to be a sense capsule, like the petrosal bone, neither of which he considers to be parts of vertebr\u00e6. Oken held the same opinion. Spix, Bojanus, and Geoffroy left these bones undetermined as to their homological signification.\ntebr\u00e6, so might we expect that the nerves of the encephalon should bear the like relationship to the cranial vertebral quantities. A spinal nerve passes between two adjacent vertebr\u00e6, and thus to six spinal vertebr\u00e6 there correspond five nerves. I have enumerated six cranial vertebr\u00e6, each one with the costal quantity, and hence the nerves passing between these six should number five, like those of the spine. These cranial nerves I consider to form five natural groups, as follow : \u2014\nThe first or olfactory nerve, being one of special sense, is distributed upon the ethmoid vertebra (fig. 481. a). The second is a group of motor and sensory branches, consisting of the optic, the third, and the fourth nerves, which pass through the optic and lacerate foramina or cleft, which occurs between the ethmoid and anterior sphenoid vertebr\u00e6. The third group of nerves is motor and sensory, consisting of branches of the fifth, which pass through the foramen ovale (fig. 482. e). The fourth group of nerves is motor and sensory, consisting of the portio mollis and portio dura ; one of these nerves is distributed to the organ of hearing, and the other makes exit at the stylo-mastoid foramen (fig. 482. r r), being destined for the side of the face. The fifth group is also motor and sensory, and consists of the eighth and ninth nerves passing out through the foramina (l, t), viz. the anterior condyloid and foramen lacerum posterius.\nThe groups of foramina, which I consider as answering to the intervertebral foramina of the spinal series, are indicated in figA&2., each group being surrounded by a dotted line, as at the point e, the place s, m, r, and the place l, t. The other two intervertebral foramina are not seen in this view of the cranial base. It is a singular fact that the external meatus occurs like a true intervertebral foramen between the petrosal and temporal vertebr\u00e6, which in the early foetal condition are naturally separated. When I view the serial order of the intervertebral foramina of the cervical spine, I find that the external meatus exactly coincides with the series.\nThere are many facts of interest which recur to me regarding fig. 482. as a form comparable to vertebr\u00e6 ; but since to record these in full would exceed the space allotted to this article, I must forego the task, and only remark in brief, that all the other foramina of the cranial base give passage to arterial and venous vessels like the vertebral foramina (g g) of the atlas and (h h) of the axis.\nThe cranial base (fig. 482.) gives evidence of a certain fact of special modification of so large an interest, that I cannot but advert to it : the fact is this\u2014the body of the axis (8, 8) passes through the body of the atlas (7, 7), and carries part of this latter (q, q) before it as its odontoid process. The body of the occipital vertebra (6, 6), passing forward to the body i of the post sphenoid vertebra (3, 3), sunders the body of the petrosal vertebra (5, 5), while the body of the parietal vertebra","page":660},{"file":"p0661.txt","language":"en","ocr_en":"SKELETON.\t601\n\u00ees altogether obliterated. By this circum- or post sphenoid vertebra, the cranial basis stance of the body of the sixth or occipital is contracted in its longitudinal axis, while cranial vertebra joining the body of the third the cranial vault (figASl.) fashioned ot the\nFig. 482.\nThe hase of the human cranium,\nShowing its serial relation with the bodies or centra of the spinal vertebr\u00e6, and also the serial homology between the foramina of the cranial vertebr\u00e6 and those of the spinal vertebi\u00e6.\nexpanded neural arches, affords ample space wherein to locate the crescent organ of the intellect.\nProp. XL. The scapulary or fore-limbs of all the vertebrated animals are homologous to one another. The variety among these organs occurs by a metamorphosis or omission of elementary quantity.\u2014 The right scapulary organ is perfectly identical with the left in the same animal body. Both the fore-limbs of the human body are identical ; those of other mammals are identical ; those of a bird are identical ; those of a reptile are identical ; and those of a fish are also identical. Osseous quantity is equal for both forelimbs of the same animal. But the forelimbs of all animals are not quantitatively equal, far from it. The fore-limbs of a mam-\nmal differ by quantity from the fore-limbs of a bird, those of a bird from those of a reptile, and those of a reptile from those of a fish. The mammal fore-limbs manifest a quantitative difference amongst all species of that class ; the avian fore-limbs the same ; the reptilian fore-limbs the same ; the piscean fore-limbs the same also. The anatomist who would undertake the task of recording the quantitative difference manifested amongst all the fore-limbs of the vertebrated classes, would require a chart as free as space and a leisure as unconfined as time. As quantitative difference is of such infinite account, I shall not therefore record it by the numerical method ; but my task shall rather be to develop that idea in generalisation, which will interpret the infinity of variety as u u 3","page":661},{"file":"p0662.txt","language":"en","ocr_en":"66 2\nSKELETON.\nbeing the product of a law of metamorphosis, exercising itself upon the whole quantity or unity.\nComparison teaches me the fact that not only are the fore-limbs of the animal classes varied amongst themselves as to osseous quantity, but I find that even the individuals of any one species have not the fore-limbs developed of invariably fixed and equal quantity ; for there is no one species free from the possibility of that occurrence which we term \u201c anomaly.\u201d The human hand is seen to develop (by no means unfrequently) a plus number of digital appendages. I have seen the like anomalies upon the fore-hands of the Quadrumana. The Ruminantia now and then develop in the fore-foot solipedal character. The solipedes are known to produce the fore-limbs in cloven stamp sometimes. The individuals of every species, I doubt not, would, if we studied them with sufficient care and in large masses, prove\nthemselves to be subject to the occurrence of a plus or minus quantitative variety to that character which is general or normal with them. It is because I find that these anomalies to species are facts not more marvellous in themselves than are the facts which vary species to species, that I will here embrace them in the general interpretation of a plus unity undergoing metamorphosis for the creation of variety. The variety between species can be nothing more than the variety which the anomaly proves to the species of normal character.\nThere is no member of the animal fabric which more interestingly illustrates the fact that nature adheres to a unity of type than does the osseous fore-limb. Whatever be the variety which fore-limbs manifest, when comparatively contemplated, still we find that the bond of unity embraces and girds within its circlet the whole subject of the variety. A proof of this fact may be seen\nFis. 483.\nA, the fore limb of the lion ; b, that of the wild boar ; c, that of the rhinoceros ; d, that of the bull ; e, that of the horse ; showing a serial degradation from plus to minus quantity.\neven in the use of that nomenclature, by which we designate all varieties of the sca-pulary organ ; for, were it not that all such members proved a greater or lesser simili-\ntude the one to the other, we should not and could not afford to generalise them under the common appellation ofscapulary organ.\nThe fore-limbs of all osseous skeletal fabrics","page":662},{"file":"p0663.txt","language":"en","ocr_en":"SKELETON.\t663\n( fig. 483.) are alike as to those segments which constitute them one and all. Those segments are the scapula (a, a), the humerus ('b, b), the fore-arm bones (c, d), the carpal ossicles (e,/), and the metacarpo-phalangeal series (1, 2, 3, 4, 5). Every species of the fore member produces these segments invariably ; I say invariably, for I am not now referring to their pathological state.\nWhen I compare all fore-limbs by the scapula (a) or proximal segment, I find that this bone is invariably present, though very much modified in several animals. As all scapulary organs of mammals, birds, reptiles (and I would add the osseous fishes, but for certain facts which require previous explanation,) produce the bone named scapula, they may be hence termed uniform as to this particular. The invariable occurrence of the humerus (b) renders them likewise uniform as to this segment. But though the fore-arm carpus and metacarpo-phalangeal segments are, as segments, invariably present likewise, still all fore-limbs are not equal or uniform as to the quantity contained in each of these segments. Considering the fore-limbs under general notice, I see that they are uniform by the proximal ends (a, b) of the organs, and variously by the distal or terminal appendages. But it is most true, nevertheless, that this variety is only quantitative, or simply a plus and minus variation, for A produces five digits, B four, c three, d two, and e only one.\nOf the two bones (c, d) constituting the fore-arm, that one which is most constantly developed in entire proportions is the radius (e). The ulna (d) is very often reduced to almost unrecognisable dimensions (d of e) ; and that part of the ulna which is most generally metamorphosed or annihilated is its distal or carpal extremity. The olecranon process and a part of the shaft of the ulna is always present.\nThe carpal ossicles (e,/), which in all forelimbs manifest a greater relationship to the radius (c) than to the ulna (d), are as constant as the radius itself. The metamorphosis of the ulna (d of e) does not appear to affect the carpal ossicles (e,f ).\nThe metacarpal bones (j%. 483.) are numerically various in these scapulary organs. Though it be true that we find them in all fore-limbs, still we do not find them produced in equal numbers. The metacarpal bones are not constant to the number of five ; but though we find them varying in a plurality of animals from the number of 5 in a to that of 1 in e, still we should not overlook the fact, that in certain fore-limbs, as D and e, where, to all appearance at first sight, a single metacarpal bone is developed, a closer inspection will prove that others may be present, though in rudimental form (5 of e).\nThe phalangeal ossicles (2, 4, 6, of B, fig. 484.) which constitute a finger are usually three in number ; but there are exceptions to this rule. The fingers themselves are generally found to correspond in number with the metacarpal bones. When there are\nfive metacarpal bones, the fingers are five in number also. When animals have only four, or three, or two, or one metacarpal bone {fig. 483.), the fingers number accordingly. There may be more metacarpal bones than there are fingers, but as many of the fingers as are present, whatever be their number, have each invariably a corresponding metacarpal bone. The rudimental metacarpal bones have, generally speaking, rudimental phalanges.\nThe thumb varies as to the number of its phalanges, and becomes a finger or a thumb according to this occurrence. The metacarpal bone of the thumb is very often present when the phalangeal thumb ossicles are absent ; and sometimes I find that some species of animals have only one phalanx for a thumb ; sometimes two, sometimes three. The digit which is a thumb in one animal (fig. 484. b), by reason of the fact that it stands apart from the other digits, is now and then laid side by\nFig. 484.\nside (a) with the other digits, and becomes a finger accordingly. I have reason to believe that the bone (1,2, next to 7 of b) which we term metacarpal bone of the thumb in one animal is the true homologue of the first phalanx of the finger appended to 8 of A, and for this reason, viz. that the metacarpal bone of the human thumb (1,2 appended to 7 of b), is constituted of two ossicles, which have become consolidated. If we class the hindmost ossicle (1 of the bone, 1, 2 appended to 7 of b) with the other metacarpal bones, then the foremost ossicle (2) will represent the first phalanx (2) of the other fingers, and this will give (as in a) three phalanges to the thumb, as to the other fingers. It is worthy of notice, that the so-called metacarpal bone of the thumb (1,2 of b) corresponds as to nucleary deposit with the first phalanx (1, 2) of the finger.\nThe foregoing mentioned facts respecting the scapulary organs will prove that they are \u201cunity in variety,\u201d the unity being a plus quantity (as A, fig. 483. with five digits) ; whereas the variety is simply a minus quantity, so rendered by the degradation or metamorphosis of the quantity of five digits, which u u 4","page":663},{"file":"p0664.txt","language":"en","ocr_en":"684\nSKELETON.\nare proper to the plus original. This interpretation will, I believe, stand the test of rigorous reasoning, and will teach the anatomist this, or nothing truthfully besides this, viz. that if the presential characters of the forelimbs manifest such a diversified condition as precludes him from naming them quantitatively equal and uniform things, still the diversity, such as we find it, can have occurred by no other process or law, save that of degradation or the metamorphosis of elemental parts. A certain part is wanting to one organ compared with another organ ; and if it be by reason of the want of this part in one organ, which part is present in another, that I am unable to name both these organs uniform, it is no less true that this very want of the part constitutes the species.\nThe fore-limbs of the man, the horse, the ruminant, the carnivore, the rodent, the marsupial animal, the bird, the reptile, are not quantitatively uniform things, and this is the only reason why they are various things. If it be this quantitative difference which induces us to classify them separately, it is only this same mode of difference which stands in our way preventing us from naming them absolutely alike. The one organ has one part which the other organ has not, and therefore both organs are various or special ; but it is still most true, that it is the want of the known part rather than the superaddition of an unknown part which constitutes both organs thus special.\nThe special thing compared with the ideal unity is simply the minus quantity compared with the plus quantity. All comparative method proves this. When I compare the fore-limb of the ass with the arm of the man, and endeavour to ascertain the law which has rendered the first as a form special to the last, I find that my analysing instrument must be not the scalpel but the calculation. For while I see that in the soliped member are arranged certain parts taking order in the self-same manner as the like parts in the human arm ; and while I further discover that the latter organ developes certain parts, which parts are not developed for the former, and that hence only arises the difference or species ; I must therefore conclude that the species depends upon the absence of something, which thing, being absent, I cannot dissect by any other instrument than the understanding ; and the thing, though absent, may be still visible to the mental although invisible to the physical eye.\nFor the knowledge of the thing absent, viz. some of the digits of e, fig. 483., is, I contend, equal to the knowledge derivable from the actual presence of the very same quantity, viz. those digits in a ; and, therefore, so long as I know the quantity which is absent from one ens to be the same as the quantity which is present to another ens, this must furnish me with the idea of equality, or the uniformity, as salientiy as if the quantity were present for both enses. When, for example,\nI compare the soliped or the cloven foot\nwith the human hand, I find that the lesser ens is contained in the greater ens, and that the other parts, which are wanting to the lesser, are still manifest in the greater; therefore I conclude, that as the greater, viz. the human hand, can undergo a metamorphosis or subtraction of parts, so as to reduce it to the proportions of the cloven or the soliped organ successively, so has the original or plus quantity, which may be regarded as equal to the human hand, undergone a metamorphosis of parts in such degree as now yields for our contemplation the special or minus quantities, which we name cloven or soliped foot.\nProp. XLI. The scapulary and pelvic members are homologous. \u2014 In a former place I have given reasons why we should consider the clavicles, the pubic, and ischiadic bones as the homologues of ribs; and therefore I shall not need their presence in this place while holding comparison between the fore and hind members.*\nThe fore-limb (fig. 485. a.) separated from the clavicle, consists, like the hind limb (e), separated from the pubis and ischium, of a fixed and invariable number of segments ; and the parts which constitute these segments in both are absolutely corresponding. The scapula (a) corresponds to the ilium (e) ; the humerus (b) to the femur (f) ; the radius (d) to the tibia (h) ; the u)na(c) to the fibula (g). The hand is manifestly the counterpart of the foot. The carpus represents the tarsus ; the metacarpus corresponds to the metatarsus : the phalanges of the hand are represented in the phalanges of the foot. The pisiform bone (q) of the carpus is similar to the os calcis (q) of the tarsus ; the great toe represents the thumb ; the little toe simulates the little finger. The common structural identity between both organs is plainly manifest at all points save one ; and this, though often attempted to be explained, has not as .yet yielded up its mystery. How happens it that the patella Qi) and fore aspect of the hind limb (e), corresponds to the olecranon (h) and back of the fore-limb (a)? I believe that the complete solution of this problem may be had from the following remarks made in reference to fig. 485.\nOn comparing the right scapulary organ (a, b, c, d) with the left pelvic. member (e, f, g, h), I find that the fore aspect of the former does not correspond to the fore aspect of the latter ; but when I compare the back of the arm a, b*, c*, d* with the front of the lower member (e, f, g, h), their correspond-\n* Yicq d\u2019Azyr regarded the coracoid and acromion processes of the scapula as representing the pubic and ischiadic bones, while Cruveilhier states it as his opinion that the spine and acromion process of the scapula has no part analogous to them in the ilium. Professor Owen considers the clavicle as the homologue of the os pubis, agreeing in this view with Cruveilhier. But, according to Professor Owen\u2019s views, it is not with the rib that either the clavicle os pubis or ischium manifests an homology ; on the contrary, he regards the iliac bone and the scapula as the true representatives of the ribs \u2014his pleurapophysial elements.","page":664},{"file":"p0665.txt","language":"en","ocr_en":"SKELETON.\n665\nence is at once manifested ; for then we have position of the scapulary organ (b*, c*, d*), the olecranon process (h) of the ulna c* in we find that the position of the bones ge-the exact position of the patella (h) of the nerally correspond with those of the pelvic lower member (e). Moreover, in this new organ (e, f, g, h) ; for the radius (d*) is now\nFig. 485.\nA, The right scapulary member, and e, the left pelvic member of the human skeleton, compared ; and showing how a torsion in the shaft of the humerus differences both limbs.\ninternal to the ulna (c*), just as the tibia (h) is internal to the fibula (g) ; while the back of the hand (n,vi,p, o) of the member b*, c*, d*, corresponds now to the dorsum of the foot (n,m,p,o) of the member f,g,h, and the thumb (o) of the member c*, D* is now laid opposite to the great toe (y>) of the member (g, h).\nNow, I also find that the back of the lower member (f*, g*, h*) represents the front of\nthe upper limb (b, c, d), and that on comparing F*, g*, h, in its present position, with b, c, d, the constituent bones of both organs correspond ; for now the ulna (c), being internal to the radius (d), is exactly simulated, by the fibula (g*) being internal to the tibia (h*). Moreover, the palm of the hand (m, n, o, p) of the limb (b, c, d) is now turned forwards, like the sole of the foot (?w, n, o, p of","page":665},{"file":"p0666.txt","language":"en","ocr_en":"666\nSKELETON.\ng*, H*), while the pisiform bone (q) of the hand corresponds in position to the os calcis (</) of the foot.\nWhile it appears, therefore, an undeniable truth that that aspect of the fore-limb (b, c,d), which we commonly call the front, is in reality structurally identical with the back of the lower member (f*, g*, h*), whereas the front of the latter organ (f, g, h) is the structural homologue of the back of the upper limb (b*, c*, d*), let us examine closely into the cause of this singular difference between both organs. Anatomists have long since remarked upon the singular twisted form of the humerus. Cruveilhier speaks of the \u201cgroove of torsion directed obliquely downwards and forwards \u201d on the humerus. This fact of torsion in the shaft of the humerus I consider as fully explaining the above mentioned peculiarities which distinguish the upper from the lower member. In primitive construction both members are identical ; but this secondary modification, viz. the torsion of the humerus, is that circumstance which distinguishes them one from the other.\nWhile, in idea, I untwist the humerus by bringing its back to the front, I at the same time unravel the gordian knot of that problem which has so long existed as a mystery for the homologist.\nThe back of the humerus (b*) presents a smooth and rounded form, like the front of the femur (f). If, in idea, I twist the femur (f) in its long axis, so as to bring its back to the front, then f* makes its linea aspera (/) perform a spiral curve forward, just as the spiral rough line (/) on the shaft of the humerus\n(b)\tmanifests its own contorted character ; and at the same time I bring the points (g, k, /), usually on the back of the lower end of the femur, forward, like the corresponding points (g, k, l) of the humerus (b). If, again, in idea, I untwist the humerus (b) in its long axis, so as to bring its back to the front, then b* uncoils its rough spinal line, and gives this line its primitive vertical direction, similar to what the linea aspera of the femur normally presents, at the same time that the points (/, h, i, Je) usually at the back of the humerus (b*) are brought forwards like the points (l, h, i, k) of the femur (f).\nin fig. 485. I have drawn both limbs, each in its front and back aspect, on either side of the common median line. When the reader will compare b, c, d with f, g, h, in reference to this line, he will find that though the ulna\n(c)\tapproaches this median line like the tibia (h), yet that this position does not render both these bones structurally homologous ; for, from the foregoing remarks in reference to the twisted condition of the limb (b, c, d), he must have learned that it is owing to this fact of torsion that the bone (c) (ulna) holds, in reference to the median line, the position of (h) the tibia, with which latter the ulna is not homologous. When we, in idea, untwist b, and bring it into the position of B*, then the radius (d*) comes into sidelong position with the median line, like the tibia (h) ; and\nnow both these bones manifest their homologous character, as well in position as in general form. The hand and the foot are, also, by these movements made to correspond. Is it not a fact of singular interest, so far as it explains the law of nature in exercising these special modifications on the structurally identical fore and hind limbs, that when, in reference to the common median line, we untwist b,d, c to the position b*, d*, c*, we then render this latter of the same aspect, compared with the ideal twisted condition of f*, g*,h*, as the figure f,g,h commonly manifests compared with b, d, c ?\nWhile we bear in mind the foregoing explanation of the presential characters of the upper and lower extremities, we are enabled fully to recognise the homological relations of these two members, as well when viewing their several constituent parts as when considering them as whole or entire organs.\nThe coracoid process a of the scapula a answers to the anterior inferior spinous process a of the iliac bone e ; the acromion process b of a to the obliterated process b of e ; the head of the humerus c of b, and both its tuberosities e d, to the head c and trochanters ed of the femur f; the rough spiral linef of b to the linea asperay of f ; the outer condyle k of b to the inner condyle l of f j for it is owing to the twist of the humerus b that the condyle k lies outermost ; the olecranon process h of b* to the patella h of f, the twist of the humerus explaining why the former part is at the back and the latter in front ; the radius d on the outer aspect of the foramen to h, the tibia on the inner side of the leg, the twist in the arm-bone explaining this difference as to their position, and also why the ulna (c) lies at the inner side of the arm, while its homologue (g) the fibula appears at the outer side of the leg. I shall here leave the reader to pursue the thread of this subject as far as he feels inclined ; for the first and radical difficulty being removed allows the subject to be easily followed through its secondary stages.*\nThe fore-limbs of all species of animals are similar to one another in all respects save that of quantity, and this quantitative difference is manifested chiefly upon the distal extremities. The obliteration of one or more parts of the distal organ renders it in the varying conditions of those forms to which we give the names of hands, paws, wings, palms, talons, hoofs, &c ; the same law of degradation is exercising on the distal extreme of the\n* Yicq d\u2019Azyr believed that the ulna represented the tibia, and the radius the fibula. M. de Blain-ville, on the contrary, regarded the tibia and the radius as homologous. Cruveilhier considered that neither of the bones of the fore-arm resembled, by itself, one of the bones of the leg, and therefore inclines to the belief that it is the upper end of the tibia which represents the upper half of the ulna, while the lower half of the tibia represents the lower half of the radius ; moreover, that the fibula is represented by the upper half of the radius and the lower half of the ulna. See \u201c Anatomie Descriptive,\u201d t. i. p. 315.","page":666},{"file":"p0667.txt","language":"en","ocr_en":"667\nSKELETON.\nhind limb, and according to the quantitative variety of these organs we characterise them by the like names. The hand and the foot are radically the same organs, not only in the same body but in all bodies ; and the law which differences these to an infinitude of special character is one of a phaseal quantitative degradation, and just as from the integer 9 may be proportioned the quantities 8, 7, 6, \u00d6, 4, 3, 2, 1.\nThe distal segments of the scapulary and pelvic members are differenced by the operation of two laws, viz. that which subtracts quantity by its annihilation, and that which\nfuses plural elements into single parts. In fig. 486, b. the hands of the sloth present, numerically, various different stages of development. In the immature being, the parts 1, 2, 3, 4, correspond to the metacarpo-phalangeal series of the human fingers ; whereas, in the adult animal, fitness requires that the elements 2, 3 should fuse into the bone 2, and thus duality becomes unity. On the contrary, in fig. a. we find the metacarpo-phalangeal series numbering as many as eight distinct elements holding permanently separate ; and I may remark, as a curious fact, that this series of eight elemental parts corresponds\nFig. 486.\nA, the fore limb of the whale ; b, the paws of the sloth\u2014immature and adult.\nexactly to the number of those nuclei from which the metacarpo-phalangeal series of the fore-finger of B fig. 484. is formed.\nProp. XLII. The sterno-costo-vertebral quantity is a proportional of the dorso-ventral quantity.\u2014Every lesser form which manifests an identity with part of a greater form proves this, and nothing completely truthful but this, viz. that the lesser viewed in comparison with the greater, owes its present condition solely to the fact of its having been metamorphosed from such another quantity as the greater form. In the spinal axis of most fishes Nature develops a series of forms like fig. 487., which I call dorso-ventral, the dorsal half (1, 2, 3, 4) being quantitatively equal to the ventral half (T, 2,3, 4) ; and the distal extreme (1, 1) of either half being terminated by fin processes, the palms (6,6). In the spinal axis of terrestrial animals Nature presents a series of proportionally diverse forms, such as sterno-costo vertebral quantities, &c. ; the dorsal sides of which are not quantitatively equal to the ventral sides, and these latter sides being still further struck proportionally diverse to each other. The difference between the spinal series of the terrestrial animal and that of the aquatic animal being a quantitative difference simply, forasmuch as the former are identical with some elementary parts of the latter, I here affirm that the lesser spinal quantity of the terrestrial animal\nis a proportional struck by metamorphosis from the greater spinal quantity of the aquatic animal. Let the comparative anatomist follow me in my remarks upon the skeletal axis of the fishes, and he will find that my explanation of the natural law of formation shall not outstep the demonstration which Nature herself offers as self-evidently truthful.\nI point to a segment (fig. 487.) of the fish\u2019s spinal axis in that region of the series occurring immediately posterior to the thorax. This segment consists of a combination of elemental pieces (4, 3, 2, 1), arranged in symmetrical superposition upon the dorsal and ventral aspects of the part which we name the vertebral body, or centrum 5. An absolute identity prevails between the dorsal elements and the ventral elements. Those of the dorsum terminate in the dorsal fin (1, 6), while those of the venter terminate in the ventral fin (1, 6) ; such segment of the fishes\u2019 spinal series is evidently a whole complete archetypal quantity, forasmuch as it proves to be symmetrical whichever way I cleave it, whether horizontally or perpendicularly, provided the line of cleavage passes through the vertebral centrum (5). If I cleave this archetypal figure in the same modes as Nature herself does, 1 produce forms identical with Nature\u2019s forms, and create of it species like the species of Nature.\nNature cleaves the ventral half (4, 3, 2,1) of","page":667},{"file":"p0668.txt","language":"en","ocr_en":"668\nSKELETON.\nthis dorso-ventral form (fig. 487.), and the result is fig. 488., having a pair of symmetri-\nFig. 487.\n6\n6\nThe dorso-ventral archetypal quantity, taken from the spinal series of the osseous fish.\ncal ribs (c c) terminated by symmetrical palms or fins (9). The ventral space (c, c,fig. 488.) is now an apartment enclosed by ribs, in which are located the blood-circulating organs, together with the viscera of selfnutrition and reproduction. The dorsal space (4) encloses the nervous axis.\nIn^g. 487. the superior or neural arch (3,3) encloses the neural space (4), and is surmounted by the interspinous bones (2,2), to which is appended the symmetrical dorsal palm (1, 1). The h\u00e6mal or inferior arch\n(3, 3) encloses the h\u00e6mal or visceral space (4), and this arch, like the one above, has\nFig. 488.\nThe dorso-ventral archetype,\nShowing how the ventral azygos ray is converted into the opposite pair of ribs by a vertical bicleavage through the median line.\nattached to it ventrad the interspinous ossicles (2, 2), to which is appended, in like manner, the symmetrical ventral palm (1,1). All these elements of the dorso-ventral archetypal quantity (fig. 487.) are bicleavable by the common median line (6, 6) passing perpendicularly through the centrum 5. If the ventral laminae (3, 3) be sundered apart from each other to a width equal to the circle 4*, 4*, then these laminae will enclose ventral space like the symmetrical costae. The dorsal laminae (3, 3) are quantitatively equal to the ventral laminae ; and it is possible for the former to be sundered apart so as to form a neural circular space equal to 4* 4* ; but it never happens that this circular space has occasion to be formed around the neural axis, for already the neural arch (4) is sufficiently capacious for its contents, and therefore the space (4) formed between the dorsal laminae (3, 3) is of dimensions, in all spinal axes, equal to the spinal cord.\nBut the symmetrical sides of the ventral ray of the archetype (fig. 487.) do actually widen apart from each other to a degree","page":668},{"file":"p0669.txt","language":"en","ocr_en":"SKELETON.\n669\naccording with the increasing bulk of the viscera of the thorax and abdomen ; and in order to allow space sufficient for the reception of these organs, the ventral ray (3, 2, 1) suffers a cleavage through its whole length, as seen in fig. 488., where the original ventral ray (7, 8, 9) has widened into the costal circle c, c.\nNow fig. 487., in its original azygos condition, or in its bicleft symmetrical form in fig. 488., may be so metamorphosed and proportioned as to produce every known form of vertebra in the spinal axes of the four classes of animals. The quantity of fig. 487., taken as a whole or archetype, represents the largest segment of all spinal axes, that, for example, which we find standing in the spinal axes of the Pleuronectid\u00e6. The obliteration of several parts of the quantity (fig. 487.) will successively represent in the remainders many forms of vertebrae ; for if the dorsal palm (1, 1) be subtracted from it, it will represent any of the palmless dorsal rays of the osseous fish ; and if the dorsal palm (1, 1), with the interspinous ossicles (2, 2), be subtracted, then the dorsal laminae (3, 3), which enclose the neural space (4), will represent any dorsal ray of the spinal axis of the terrestrial animal. When the dorsal and ventral palms (1, l), together with the dorsal and ventral interspinous ossicles, are subtracted from the archetype 487.), then the quantity composed of (5) the centrum and of (3, 3) the neural and haemal arches equals that vertebra which we find in the tail of cetaceans, viz. that vertebra which possesses the chevron bones. The chevron bones are fashioned of the inferior or haemal laminae (3, 3), and when the neural or the haemal arch produces the neural or the haemal spinous process, this process is a part of the interspinous ossicles left remaining, as at g> g (fig- 488.)\nWhen the ventral ray (3, 2, 1) of the archetype (fig. 487.) widens to the costal arch c, c in fig. 488., this arch is left standing at the thorax of some animals, and even at the venter of others. As fig. 488. stands in its present quantitative character, it may be found in the abdomen of fishes still having the parts 1 and 2 attached and persisting, or obliterated and lost to the original quantity, as the case may require. At the dorsal aspect of the spinal axes of all terrestrial animals it may be understood that the parts 1 and 2 of fig. 488. are lost or subtracted.\nIt is the ventral ray, consisting of the parts 7, 8, 9 {fig. 488), which suffers median cleavage and widens into the costal arches (c, c). As a certain proof of this fact, I may remark, that where the full ventral ray persists as at 7, 8, 9, there we never find the full costal arches (c, c) existing; and where these latter are existing, there we never find the ventral ray. As the one becomes converted into the other, it is hence impossible for the same ens to exhibit both conditions of form at one and the same time.\nWhen the ventral ray 7, 8, 9 (fig. 488.) has widened into the costal arches, these arches\nmay and do suffer a metamorphosis of quantity to the same degree as when in their original azygos condition. Thus the ribs (c, c) become symmetrically proportioned or obliterated successively at the points f, e, d, by imaginary lines radiating from the sternal centre at 9. When these costal arches (c, c) meet at the central point 9, then we name the ribs sternal ; when they fall short of this point 9, either at the point / or e, we name these ribs asternal-, when they become obliterated as far back as the point d, then we name them, as in the lumbar spine, the transverse processes.\nAs every law in nature is phaseal and graduated, so is this the distinguishing character of the law of formation. The ventral ray (7, 8, 9), after undergoing a cleavage into symmetrical halves, will present, in various classes and species of animals, a phaseal gradation in the process of widening, and assume the form of the arc a, b, and c, successively, according to necessity.\nIn the caudex of the saurian or cetacean, we find vertebrae producing at the same time the neural arch and spine, the haemal arch and spine, together with the costal process (c, c), jutting laterally from the centrum (5) as far as the point d; when this is the case, then the haemal arch and spine is fashioned of that quantity of the costae which intervenes between d and f, and which, being severed from c at the point d, is bent inwards towards the median line 6, 7, thus assuming a second time its azygos position. In some aquatic mammalia (the porpoise, dolphin, &c.) there remains at the dorsal aspect some trace of the dorsal form (1, 2, 3, of fig. 488.). The cetacean dorsal fin is thus explained.\nProp. XLIII. The scapulary and pelvic pairs of limbs are proportional quantities metamorphosed from the dorso-ventral archetypes.\u2014 The scapula disconnected from the clavicle is the quantitative counterpart of the iliac bone separated from the os pubis and ischium. Having in a former place remarked upon the structural homology which relates clavicles, pubic bones, and ischiadic bones to ribs ; and having also pointed out the homological relations between the scapulae and the iliac bones, we shall in this place first consider the structural homology between these latter osseous quantities and the vertebrae, and next the homological relations between the fore and hind limbs, the ribs, and the dorso-ventral rays.\nThe dorsal vertebra, viewed from behind, is represented in A (figA89.). b represents the dorsal aspect of the two scapulae conjoined, and c represents the two iliac bones placed base to base. Is there a structural identity apparent between these three figures ? and in what points of character do they correspond? To this question I answer in almost all points ; for not only do these forms, viewed in their entiret}', correspond, but even their mode of genesis is identical.\nThe vertebra (a) is a symmetrical form, consisting of opposite laminae (c, c), which","page":669},{"file":"p0670.txt","language":"en","ocr_en":"670\nSKELETON.\njoin each other at the common median line (a, b)., From these laminae we find jutting out laterally the exogenous transverse processes ([d, d), each of which is tipped by an epiphysis.\nThe pair of scapulae (b) forms a symmetrical figure : both scapulae (c, c) are evidently similar to each other, and also to the laminae (c, c) of the vertebra (a).* From each scapula we find projecting laterally an exogenous\nFig. 489.\nShowing that the pair of scapulas and the pair of iliac hones, compared with the pair of vertebral laminae, prove a homological relation, and also that the heads of the humerus, the femur, and the rib are similar to one another.\nprocess (d, d), which is commonly named acromial process, and each is tipped with an epiphysis also. These acromial processes evidently correspond to the transverse processes (d, d) of the vertebra (a).\nThe pair of iliac bones (c) likewise forms a symmetrical figure when laid crest to crest. These two iliac bones (c, c) are homologous, not only to each other, but to the two scapulae (b), and to the two vertebral laminae of a. From each iliac bone there projects laterally the process d, d, which answers to the acromion process d of b, and to the transverse process d of a. The process d of c is named anterior inferior process of the ilium, and it is tipped with an epiphysis.\nThe law of symmetry becomes the exponent of the structural identity existing between the figures a, b, and c ; for we find the com-\n* If this homological relation which I point out as apparent between the pairs of scapulae and iliac bones, with the pair of vertebral laminae, be true, then the homological relation which Professor Owen describes as existing between the scapulae and the ribs, as also between the iliac bones and the ribs, cannot at the same time be received as a true doctrine.\nmon median line (a, b) bisecting them through their conjoined bases. The opposite halves of each of these figures form symmetrical figures, but it is also true that the half of each is asymmetrical.\nNow, as the rib (e,/) articulates with each side of the vertebra (a), and is overhung by the transverse process (d), so the humerus (e,/) articulates with each side of the scapular form (b), and is overhung by the acromion process (d). In just the same relations, the thigh-bone (e,f) of the iliac form (c) is overhung by the anterior inferior spinous process (d). It becomes evident, therefore, that the heads of the rib, the humerus, and the femur correspond ; and this correspondence is manifested, not only by the position occupied by each, but likewise by the genetic character of all three ; for the parts of the rib ([e,f ) of a are epiphyseal, the same of the parts (e,f ) of the humerus of b, and the same of the parts (e,f ) of the femur of c. The articular facets (/) of the rib, the humerus, and the femur correspond; the tuberosity (e) of the rib, the humerus, and the femur likewise correspond. The spinous borders of the opposite vertebral laminae of a, the basis of the scapulae (b), and","page":670},{"file":"p0671.txt","language":"en","ocr_en":"SKELETON.\n671\nthe crests of the iliac bones (c) are bordered with epiphyses ; and this also illustrates a similarity between them.\nNow, having before demonstrated the fact that the sterno-costo-vertebral quantity was a proportional of the dorso-ventral archetype, it must follow that, while a structural homo-\nlogy exists between the scapulary or pelvic pairs and the costo-vertebral quantity, so, likewise, should the limbs themselves prove to be the proportionals of the dorso-ventral archetype ; and this we shall next consider.\nIn fig. 490. I represent the dorso-ventral archetype (a), the scapulary pair of members\nFig. 490.\nShowing the homological relation between the dorso-ventral archetype (a), the scapulary organs (b), and the sterno-costo-vertebral quantity\" (c), and that the difference between these three figures is merely quantitative.\n(b)\t, and the sterno-costo-vertebral quantity\n(c)\t. What are the corresponding points and the differential characters between these three figures ? Is the difference between them one of quantity merely ? Evidently it is so, and therefore I have marked the corresponding parts of each with the same letter.\nIn the dorso-ventral archetype (a), the lamin\u00e6 (4) enclose the neural space (5). In the symmetrical form, constituted of both scapulary limbs (b), the opposed scapulae (4) enclose the space (5) between them. In the\nsterno-costo vertebral form (c), the lamin\u00e6 (4) enclose the neural space (5).\nIn A we find the ventral arches 8 (call these either haemal arches, costae, or what you will) enclosing the ventral space (9). In b the symmetrical humeri (8) enclose the space 9. In c the opposite ribs (8) enclose the space 9. In a the neural lamin\u00e6 (4) and the haemal lamin\u00e6 (8) project dorsad and ventrad from the centrum (5). In b the scapulae (4) and the humeri (8) project in the same way from the coracoid bodies (6), which I consider","page":671},{"file":"p0672.txt","language":"en","ocr_en":"672\nSKELETON.\nto correspond with the bisected vertebral centrum (6) of A. In c the laminae (4) and the ribs (8) project in the same way from the centrum (6). In c the transverse processes (7, 7) project from the laminae (4), just in the same relative position as the acromion processes (7) project from the scapulae (4 of b). In a there are no processes corresponding with these ; but we should recollect that these processes are merely apophyses, and not as distinct elementary constituent parts of the vertebral quantity.\nIn a the symmetrical haemal spines or ossicles (11) correspond to the bones of the forearm (11 of b). In c the ribs (8) unite at the sternal median line (10), and the ossicles (11) are not existing.\nIn a the ventral ray is terminated by the palm 12, which is symmetrical; while in b the scapulary members are terminated by the palms 12, which are also symmetrical. These palms are lost at the point 12 of c.\nWhen we compare a with b, we find that all their parts correspond, except in this particular, viz. that a produces dorsad the bones 2 and the palms 1. In b these parts are lost. When, again, we compare c with a, we find that the parts 1 and 2, as well as the parts 11 and 12, are lost to c. It is this loss of quantity which diff\u00e9rences b and c from a.\nThe existence of the parts 1, 2, 4 at the dorsum, and of the parts 8, 10, 12 at the ventrum of fig. a., renders this fig. symmetrical and equal at the back and venter. The obliteration of the parts 1 and 2 at the dorsum of b renders the figure unequal as to back and venter. But the loss of the parts\nI\tand 2 from the dorsum of c, and the parts\nII\tand 12 from its venter, leaves this form still similar as to back and venter, although unequal to the dorso-ventral archetype (a). This difference is merely quantitative.\nNotwithstanding this quantitative variety between figs, a, b, and c, we still find them symmetrically cleavable by the common median line, and this circumstance points to their analogy. Fig. a. is a dorso-ventral limb ; fig. b. is a ventral limb ; fig. c. is a ventral costiform limb ; and it is a remarkable fact that this latter quantitative form, though usually performing those motions which are required in the act of respiration, is, in some species of animals (the ophidian and the lizard), operative as a locomotive member.\nFig. a. encloses neural and haemal space at the points 5 and 9, and stands in spinal series with all its fellows of that series. It is an archetype compounded of the parts called vertebra ; at the dorsum and venter'of which stand the parts called the limbs. Fig. B. is a proportional quantity of such another archetype as A ; and having suffered bicleavage through its median line, it falls asunder on either side of the animal, and encloses the thorax between its opposite halves, at the space 5, leaving the prehensile organs, consisting of 8, 11, 12, playing freely on either side of the body. Fig. c. is a proportional quantity, also of such another archetype as\nfig. A, and stands in spinal serial order with this latter, enclosing neural and haemal space at the points 5 and 9. The spinous ossicle (3) which surmounts the laminae (4 of c), is part of the quantity marked 2 in a, the archetype. The spinous ossicle (3 of c) and the epiphyseal nucleus (3 of b), which borders the bases of the two scapulae, correspond.\nWhen fig. c. forms the sternum ( 10) by a union of the ribs (8, 8), this sternal line in all animals may be regarded as that median place where the archetypal quantity ( 11 and 12) is lost ; and in the same way, when c forms the spinous union at the dorsum, surmounted by the bilateral spinous ossicles (3), this spinous point of the skeletal axis of all animals may be said to be that place where the archetypal quantity (1 and 2) has been subtracted.\nThe mode in which the vertebriform scapulae contract a connection with the costiform clavicles and coracoid bones*, is similar to the mode in which the vertebriform iliac bones become joined to the costiform pubic, and ischiadic bones, as a reference to fig. 491. will prove.\nWhen the two iliac bones, to which are appended the hind limbs, fall from vertebral spinal series, bicleft on the animal\u2019s sides at the lumbar region, they abut on either side of that region of vertebral series, which hence\nFig. 491.\nShowing the signification of the bones of the shoulder and hip ; that the clavicles, pubic and ischiadic bones refer to the ribs, while the scapulas and iliac bones refer to the vertebras.\nbecomes the sacrum ; and the ilio-sacral symphysis is thus formed.\nIn a (fig. 491.) the iliac bone (h, h) will be\n* I mean the bones called \u201ccoracoid\u201d in birds and reptiles, not the mammal coracoid processes, for I have already named these latter to be the bicleft centrum of the scapular vertebra.","page":672},{"file":"p0673.txt","language":"en","ocr_en":"SKELETON.\nobserved to occupy the interval between (e, d) the ischiadic and pubic bones, and (3, 4, 5) the sacral vertebrae. The junction between the ilium and the sacral vertebrae is called sacro-iliac, whereas by the union of the ilium (h,h) with the pubic and ischiadic bones (d,e), the articular cup called acetabulum (g) is formed. While the ilium becomes thus intercalated between the pubic and ischiadic bones on the one hand, and the vertebrae on the other, it severs the former from connection with those vertebrae to which, as costae, they properly belong; and it obliterates that costal quantity indicated in dotted outline at 3, 4, 5, which quantity, if it still persisted, would unite the pubis and ischium to their proper vertebrae. In fig. 491. I have represented in a some of those line\u00e6 transversae (a, b, c), which sketch out the form of the original ventral ribs proper to the lumbar vertebrae ; and it will be seen that a, b, c hold series with (d) the pubic bone, and (e) the ischiadic bone. Between a, b, c, as the ventral ribs, occur the intercostal spaces (fif), and between the pubic and ischiadic bones (d, e) occurs that space (/) which, in human anatomy, is named \u201c thyroid foramen.\u201d Is not this thyroid foramen an intercostal space, if d and<? becost\u00e6 proper to the sacral vertebrae? And do not the pubic and ischiadic symphises at the point k correspond to the linea alba (/, /), which stretches between the pubis and sternum?\nIn fig. b. we find the scapula ([k, k, h, i) occupying, at this region of series, a position similar to that which the iliac bone holds elsewhere. But beneath the scapula the ribs (2, 3, 4), for obvious purposes, persist ; while beneath the iliac bone they are wanting. This want of the ribs beneath the iliac bone, and this presence of the ribs beneath the scapula, constitute the diff\u00e9rence.\nIf those portions of the ribs (b and c of Jte-B-) which lie beneath the scapula suffered metamorphosis, then b and c would abut upon the glenoid cavity h, and would be to the scapula what the pubic and ischiadic costiform bones are to the ilium ; and then v/e should have, between b and c of fig. b., the intercostal space^ as corresponding to the thyroid aperture. It is the costiform clavicle (a of b) which becomes severed by the scapula from its vertebra behind, just as the costiform os pubis is severed by the iliac bone from its vertebral quantity.\nThe cotyloid cavity (g of a) is formed by the junction of three bones, viz. the ilium ([h h), the os pubis (d), and the ischium (e) ; but it is the iliac facet of the cotyloid cavity which alone corresponds to the gienoid cavity of the scapula. If the ribs (b or c of fig. b.) happened to be dissevered from their vertebrae behind by an interval equal to the size of the scapula (k, k, 1i), and if these sternal ends of the ribs (b, c) then joined themselves to the glenoid articular surface (b) of the scapula, the three bones (h, b, and c) would also form a cotyloid cavity for the head of the humerus.\nIn those animals (birds, reptiles, &c.), where von. iv.\n673\ntwo clavicles are required to be metamorphosed from ribs, they illustrate still further the. structural analogy which exists between them and the ischiadic and pubic bones, which latter exhibit, in relation to the ilium, the same character that the clavicles manifest in relation to the scapula.\nIn fig. a. the os penis (l*) will be seen to fall behind the symphisis pubis, while in fig. b. the episternal ossicles (/*) will be noticed as producing the sternal median line forwards into the neck. At the subpubic region, where l* occurs, and at the episterrfal region, where the episternal ossicles occasionally appear, the sternal median line is bounded in the animal ; but in the comparative abstract animal, these points may be regarded as unfinished.\nProp. XLIV. The cranio-facial apparatus of segments are proportionals of the dorso-ventral archetypes.\u2014If it be true that the vertebral quantity is a proportional of the sterno-costo-vertebral quantity, and this latter a proportional of the dorso-ventral archetype, then it must follow that the cranio-facial apparatus, which appears to bear a structural homology with the sterno-costo-vertebral quantities, is also constituted of segments which, like these latter, are proportionals of the archetypal quantities. Even though the whole animal kingdom did not present us with a skeletal form, upon whose cranium the dorsal rays persisted complete, still the above-mentioned inference may be legitimately drawn ; but when, amongst the class of osseous fishes, we findy%. 492., upon whose cranium the dorsal rays actually persist, then the \u00e0 priori and the \u00e0 'posteriori trains of reasoning meet and answer to each other, while standing in presence of the fact itself, as nature produces it.\nIn fig. 492. we see that the archetypal dorso-ventral quantities (a, b, c, d) are continued into the head, not only by their centra, their costal inferior arches, and their dorsal lamin\u00e6, which form the neural arches from 17 to 1, but also by their dorsal interspinous ossicles from m to nt and by their dorsal palms from o to p.\nThe head of the osseous fish (fig. 492.) of the class Pleuronectid\u00e6 may be accounted, therefore, as constituted of a series of the dorso-ventral archetypes specially modified. Between the cranial and the facial structures is continued the line of spinal centra ; and from these, as from the centra elsewhere throughout spinal series, the dorsal and the ventral rays project. The inferior cranial rays are the jaw-bones (e f h h) and hyoid arches (g, g) ; the superior cranial rays are the forms o p, m n.\nProp. XLV. The cranio-facial apparatus is the origin of the dorso-ventral archetypal series, and the caudal apparatus is its termination.\u2014 In the same animal, whose cranial structures are still crested by the dorsal rays complete, we find the opposite caudal extreme (/g.493.) also crested by similar rays, dorsad as well as ventrad. The spinal centra (n, m, l #) still produce the entire rays (o, q) above and below, while the terminal centrum (\u00ab) stands as\nx x","page":673},{"file":"p0674.txt","language":"en","ocr_en":"674\tSKELETON.\na nucleus, around which are arranged, in pal- zontal ray(9), fashion the fan-shaped caudal fin. mate order, the rays of nine archetypes, which, This caudal fin, whose rays describe the arc bending towards each other, and to the hori- p q, is composed of the palms of nine arche-\nFig. 492.\nThe cranio-facial apparatus of the osseous fish (Pleuronectidce),\nIndicating the metamorphosis of twelve or more spinal quantities in its composition.\ntypes, radiating from the common centre (a). The nine inferior palms are those which number from 17 to the palm 9 ; and the nine superior palms are those which number from 1 to the palm 9 ; while the azygos palm 9 may be regarded as composed of the dorsal and ventral palms of the last archetype bent towards each other, and becoming in the horizontal line fused together. The bones (o, p, q)y are the counterparts of the neural and haemal laminar arches, assuming the same palmate order as the palms. The head (fig. 492.) and the caudex (fig. 493.) constitute the origin and termination of spinal series, and are examples of special modifications exercised upon the original archetypal quantities.\nProp. XLVI. The uniform archetypal series undergoes a graduated metamorphosis of its quantities for the production of all varieties of skeletal species.\u2014 In fig. 494. I represent the archetypal series of the dorso-ventral quantities constituting the uniformity, forasmuch as all the segments are plus and quantitatively equal. The segment 1 is equal to the segment 38, and to all the intervening segments. This uniform series of quantities appears finite, like the right line (cd) which passes through its centre j but as the right line itself\nis but a part or proportional of that ideal line which is infinite or boundless, so of the series of archetypal quantities, numbering in the figure from 1 to 38 ; for this series may like number be produced to infinity in imagination.\nIn the serial line (fig. 494.) which is composed of 38 archetypal dorso-ventral quantities, we do not as yet distinguish any special differences ; and this is owing to the fact that all the quantities composing the series are similar or homologous ; neither can we discover any reason why we should name either of the extremes of this serial line (d c) as the origin or the termination in preference to the other extreme, for the segment 38 is equal to the segment 1 and hence it matters nothing to the entities themselves at which end of the series we commence the enumeration. In nature there is no instance of a skeletal axis constituted of such a uniform serial line of quantities as those of fig. 494., but yet it is possible to prove that every skeletal axis is part of such an original series. That skeletal axis which approaches nearest to the absolutely uniform condition of fig. 494. is to be found amongst the class Pisces.\nThe skeletal fabrics of all animals are sym-","page":674},{"file":"p0675.txt","language":"en","ocr_en":"SKELETON\t675\nbolic of that sphere in Nature in which they those of aquatic and terrestrial animals. The are destined to live and act. The two main aquatic class, inhabiting the watery regions, primary divisions of differential forms are symbolise their native element, in which\nFig. 493.\nthey move submerged ; and accordingly we prone upon the earth, produce the locomotive find them treading this medium by loco- organs suited to that motion, viz. on the motive members arranged dorsad as well as ventral side only.\nventrad ; while the terrestrial class, moving All species of the class of fishes approach\nFig. 494.\nThe uniform archetypal spinal series,\nShowing how the species or variety is proportioned from it as the plus quantity.\nnearer to the plus uniform character of the motive or fin member dorsad, whereas no serial axis (Jig. 494.) than any of the species of species of the terrestrial-moving class requires the terrestrial class ; for all species of the any form of such a member. Even the mam-former class produce some form of the loco- malian cetaceans are furnished with a remnant\nx x 2","page":675},{"file":"p0676.txt","language":"en","ocr_en":"SKELETON.\n676\nof the dorsal fin, since they are denizens of the world of waters. The tribe of fishes known as Pleuronectid\u00e6 is bordered dorsad as well as ventrad by the locomotive palm-organs, and therefore they simulate the series of fig. 494. more closely than any other class of animals. The Pleuronectid\u00e6 are the most archetypal class of animals in Nature ; for the first step of the law of formation in the metamorphosis of fig. 494. is to create a cephalic end (yTg.492.) and a caudal end {fig. 493.) to this series of whole quantities, by a modification of a certain number of the archetypes at either end ; and thus the animal of the class PJeuronectid\u00e6 is fashioned, having the continuous palmed or fin-organ still persisting dorsad and ventrad on those spinal archetypes which stand in series between the cephalic and caudal extremes.\nThe structural composition of the head will vary according to the number of those serial archet}rpes which suffer metamorphosis for its creation. For if we suppose that the six quantities which are included within the circle q c r {fig. 494.) should be subjected to cephalic metamorphosis, we still can assign no reason why Nature should limit hers\u00ealf to the number six, or any other number, if necessity required the metamorphosis ofagreater number for one species of cephalic apparatus and a less number for another. Although in a former place I have numbered six segments as proper to the composition of the human head, still I am by no means of opinion that Nature limits herself to number six in the creation of all other species of cephalic apparatus ; on the contrary, I shall not hesitate to assert it as a fact, that {fig. 492.) the head of the plaice may be taken as an instance in which fourteen dorso-ventral archetypes have suffered cephalic modification.*\nThe alternate fin-organs at the back and venter occur by the alternate metamorphosis of certain members of the palms of the continuous series of archetypal quantities. In the Pleuronectid\u00e6, the dorsal and ventral palmed fins are continuous for the entire length of the spinal axis, as in fig. 494. ; but in other classes of fishes we find the fins occurring isolated at certain regions of the spinal axis : such, for example, as the fins called dorsal, jugular, abdominal, anal, and caudal ; and this alternation may be explained by referring to fig. 494. If the palms which I have included in the semicircles k t., m n happen to be metamorphosed or subtracted, then the isolated dorsal fin (m o l) will remain as we find it presenting in many of the class Pisces, and even in some of t-he cetaceans. The fin-\n* Professor Owen enumerates four vertebral segments as composing the heads of all animals of the four classes. For my own part, I see no reason to entertain the opinion that Nature limits herself to a fixed number in the segments of the head, any more than she does in constructing the cervix, the thorax the loins, the sacrum, or the caudal region of the spinal axes. Cams and Oken speak of the number Jive, as though Nature limited the operation of her law in patronage to this magical quinque in vertebrate creation.\norgan is composed in all cases of a plural number of palms; the number always corresponding to the dorsal rays of the archetypes. The palm is a hand, while the fin presents as a series of hands.\nWhen the series of archetypal quantities suffers metamorphosis at certain lines which the creative hand of Nature draws through it, the animal design or species is struck out accordingly. When all quantity lying external to the converging lines o d, p d undergoes metamorphosis or subtraction, then the series of quantities which happens within these lines will exhibit the condition of proportional and progressional quantities, such as we find standing in the caudal region of many animals. When Nature draws the right line a b through this region of the serial archetypes, and at the same time metamorphoses all quantity above or dorsad to this line, she creates the dorsal region of the spinal axis of all terrestrial animals, to which are remaining those parts which we name the neural arches, sufficient for the protection of the spinal cord.\nThe quantity which occurs within the lines a b, F g answers to the thoracic ophidian skeletal axis, whose ventral or opposite costal arches occur by a bicleavage of the azygos ventral rays. The thoracic series of each skeletal axis is formed after the same manner as that of the ophidian. The numerical length of every thorax varies according to the number of those serial archetypes of fig. 494. which suffers thoracic metamorphosis ; and its position in spinal series varies also according to the numerical position of those archetypes which undergo a thoracic modification ; for if they be the segments which hold serial order between that which numbers (infig. 494.) as 13, and that which numbers 30, then the thoracic length will correspond to these numerical segments.\nWhen the head is fashioned of the six quantities included in the circle q c r, while the neck is proportioned by the line e d, from six, or seven, or more of those quantities which succeed the head, viz. those segments between 7 and 14, 15, or 16, then the neck will number accordingly; and when the thorax is to succeed the cervix, then the twelve or more segments which succeed those of the cervix are proportioned thoracically by the lines F g. When, lastly, the lumbar, sacral, and caudal regions are to succeed the thorax, it is the line f d which gives to these regions their several quantitative characters.\nThe law of \u201cunity in variety\u201d appears \u2022therefore to be plainly demonstrable as an archetypal plus series of quantities, undergoing a graduated metamorphosis ; and if, by the order of the foregoing remarks, I have left upon the reader\u2019s mind the idea that the proportional variety constitutes the species of one form of skeleton compared to another, and to all others of the four classes of vertebrate animals, then my object has been attained by the course of argument which 1 have pursued.\n{Joseph Maclise.')","page":676},{"file":"p0677.txt","language":"en","ocr_en":"SLEEP.\n677\nSLEEP. \u2014 This term is employed to designate that state of suspension of the sensory and motor functions, which appears to alternate, in all animals, with the active condition of those functions, and which may be made to give place to it by the agency of appropriate impressions upon the sensory nerves.\nAlthough this may seem a complex definition of a state which seems to be in itself so simple, yet it will not be found easy to alter its character without rendering it less stringent. We more especially desire to exclude from it the abnormal condition of coma, in all its forms ; whether resulting from the influence of pressure or effusion within the cranium, or consequent upon the poisoning of the blood by narcotic substances, or occurring as part of that inexplicable series of phenomena which are termed hysterical. The state of coma, where not so intense as to affect the movements of respiration and deglutition, is identical with profound sleep as regards its obvious manifestations; but there is this important difference, that simple sleep may be made to give place to activity by the application of appropriate stimuli to the sensorial system ; whilst in complete coma, no impressions on the sensory nerves have any power of bringing back the consciousness. Between these two conditions, however, every gradation may be seen ; as in the heavy sleep produced by an over-dose of a narcotic, in incomplete hysteric coma, or in the torpor resulting from slow effusion within the cranium.\nThe necessity for sleep seems to arise from the fact, that the exercise of the animal functions is in itself destructive of the substance of the organs which minister to them ; so that, if the waste or disintegration produced by their activity be not duly repaired, they speedily become incapacitated for further use. This doctrine is now so generally admitted, that it does not seem requisite to adduce proofs in its support. The substance of muscles is regenerated during the suspension of their action in simple repose ; and it is not essential that, for this purpose, a state of unconsciousness should intervene. As the substance of the nervous centres and trunks, more especially the former, undergoes a similar disintegration as a necessary consequence of its activity, this too requires a period of repose for its regeneration ; but the repose, or suspension of functional activity, of the sensorial portion of the nervous system, necessarily involves unconsciousness ; and it appears to be on the nutritive regeneration which takes place during true sleep, that its refreshing power depends. No such refreshment is experienced from the unconsciousness of coma, however prolonged ; and there are some forms of ordinary slumber in which it is more or less deficient. The organic functions are not affected in any considerable degree by the suspension of the sensorial ; for we find that not only are the operations in which these functions essentially consist uninterruptedly carried on, but that\nthe muscles, nerves, and nervous centres also which are concerned in maintaining them, are enabled to sustain an unintermitted action. Thus the movements of the heart are not, in warm-blooded animals at least, normally suspended, from the first development of that organ until the close of life ; the respiratory motions, in like manner, are kept up uninterruptedly from birth to death ; and the propulsion of food along the alimentary canal during sleep by the peristaltic contraction of its muscular coat, the sustained action of the sphincters, the peculiar position of the eyes, and the active state of the extensor muscles of the legs in animals which sleep standing, are additional evidences that the state of continuous repose is not required for the renovation of the powers of certain parts of the nervous and muscular apparatus. To use Dr. Marshall Hall\u2019s phraseology, \u201c the true spinal system never sleeps ; \u201d and, whatever we may think of the existence of his \u201c true spinal \u201d system of nerve-fibres, as distinct from those which minister to the functions of the encephalon, there can be no longer any doubt that the ganglionic portion of the spinal cord is a distinct centre of nervous action, which retains its power of actively responding to impressions made upon it, during the profoundest repose of the other centres ; whilst, from the complete suspension of its functions, even for a very brief period, death inevitably results.\nIn following out our inquiry into the nature of sleep, and of certain conditions allied to it, we shall find it convenient to regard the encephalon as composed of four leading or primary divisions : 1. The medulla oblongata, which essentially consists of a prolongation of the spinal cord, including the centres of respiration and deglutition ; and also having incorporated with it, without properly forming part of it, the ganglia of hearing and of taste; 2. The ganglia of sensation, including, with the olfactive, optic, auditory, and gustative centres, the corpora striata and thalami optici, which are probabty, when taken together, to be regarded as the ganglia of tactile sensation*: 3. The hemispheric ganglia (Solly), or peripheral portion of the cerebral hemispheres: and 4. The cerebellum.\nThe first of these divisions really belongs to the spinal cord, and, like it, is constantly active. \u2014 The second appears collectively to form the true sensorium, to which external impressions must be conveyed, in order that they may be felt (each class of sensations being received through the medium of its own ganglion), and from which proceeds the stimulus to those automatic movements which can only be excited by a sensation. Such are the truly instinctive actions. \u2014 The third division, of which scarcely a rudiment exists in the lowest fishes, although it constitutes by far the largest proportion of the encephalon in man, seems to be the instrument through which ideas are generated, by which they are retained and made the subjects of intellectual\n* See British and Foreign Medical Review, vol. xxii. p. 510.\nx x 3","page":677},{"file":"p0678.txt","language":"en","ocr_en":"678\nSLEEP.\nprocesses, and by which voluntary determinations are formed. Impressions made upon the organs of sense would seem only able to act on the hemispheric ganglia through the medium of the sensorium ; whilst the voluntary determinations, resultingfrom the exercise of the reasoning powers, can only act on the muscular system by the transmission of a downward impulse from the hemispheric ganglia to the automatic centres, in which the motor nerves originate.\nIf this be a true representation, the ordinary phenomena of sleep are not difficult of comprehension. The state consists essentially in suspended activity of the sensorium, so that impressions made on the organs of sense are neither felt nor 'perceived, \u2014 that is, neither excite sensations, nor give rise to ideas. In like manner, those automatic movements which are dependent upon sensations for their excitement are suspended; and as the torpor of the sensorium cuts off the functional connection between the hemispheric ganglia and the muscles, the latter cannot be called into activity by any mental operations in which the former may be concerned. In ordinary profound sleep, the hemispheric ganglia would seem to be in the same passive condition as the sensorium itself ; so that all mental activity is suspended. In dreaming, however, there is a train of ideas, called up by the laws of association, and not regulated by any voluntary control, bespeaking a partial activity of the hemispheric ganglia. Into the conditions of this phenomenon we shall inquire hereafter ; at present only observing, that if the sleep be deep, external impressions are as completely unperceived by the dreamer, as they are in a state of entire unconsciousness ; and that, in like manner, the strongest desire felt by the dreamer to perform certain bodily movements, even when he fancies that his life depends upon them, is as ineffectual as if he were suffering from a total paralysis. If external impressions are in any degree felt by the dreamer, or his volition can exert its power over the movements of his body, the sleep is not profound, but rather approximates towards the state of somnambulism or sleep-waking, in which the sensorial as well as the hemispheric ganglia are in a condition of partial activity.\nThe state of simple sleep, again, is allied to that of hibernation (see Hibernation) ; the difference between them being essentially this, that in the latter condition, besides the profound torpor of the sensorial centres, there is a great diminution or complete suspension of the activity of the organic functions. We may trace, in fact, every gradation between the simple repose of the sensorial centres, in which the state of sleep essentially consists, to that complete suspension of all the functions of life, which is of ordinary occurrence, during the winter season, in coldblooded animals. Many of these can even endure the freezing process without the loss of their vitality ; their activity being restored by the renewal of warmth. Next to this is the\ncondition of those hibernating mammalia, which pass the winter in a state of uninterrupted torpor, and in which the organic functions seem reduced to their lowest possible amount of activity, short of entire stagnation. This reduction is manifested in the slowness of the circulation, the infrequency of the respiratory movements, the low degree of heat sustained, the abatement of the demand for food, and the small amount of carbonic acid, urea, and other excretory products, set free during the persistence of the hibernating state. But there are other hibernating mammals, in which the reduction is less decided, and the torpor less profound ; these animals awaking from their repose at long intervals, taking food from the store which they have prepared, and again relapsing into inactivity. And there are others, again, in which it differs but little from ordinary profound sleep, except that the proportion of time passed in the waking state is much less than usual. Further, it is a curious observation of Dr. M. Hall\u2019s (loc. cit.), that the ordinary diurnal sleep of certain hibernating mammalia presents, in the reduced activity of the organic functions, an approach to the torpor of their winter state.\nSleep of Plants. \u2014 The complete suspension of the organic as well as of the animal functions during the hibernation of coldblooded animals corresponds with what has been termed the ivinter sleep of plants. But plants have also what has been called a diurnal sleep ; and although it is obvious that plants can present no phenomena really analogous to those in which we have defined the sleep of animals to consist, yet there are periodical changes in the condition of their leaves and flowers which are deserving of consideration under this head, especially as affording ing an additional indication that even in the functions of organic life there is a tendency to a more or less decided alternation of activity and quiescence. The parts of plants which exhibit the changes in question, are the leaves and the flowers. In the former we frequently notice an entire difference in the nocturnal and diurnal aspects of the leaves, which is the result of a periodic change, affecting either the position of the leaf as a whole, or that of the several leaflets of which a compound leaf is formed. The petioles, or stalks of the leaves or leaflets, either bend upwards or downwards ; so that the flattened surface of the leaf is either elevated or depressed. This is not a result of simple flaccidity ; for, as De Candolle remarks *, the nocturnal position is maintained with the same rigidity and constancy as the diurnal ; so that the \u201c sleeping\u201d leaf would be broken, more readily than it could be forced into the position which is proper to it during the day. Eleven different modifications are enumerated by the distinguished botanist just cited, in the manner in which the leaves incline themselves to the stalks on which they grow. Thus, of the entire leaves which exhibit this phenomenon, some sleep face to face, others back to back,\n* Physiologie V\u00e9g\u00e9tale, p. 855.","page":678},{"file":"p0679.txt","language":"en","ocr_en":"SLEEP.\n679\nothers fold in at the sides so as to embrace the stem or to protect the flower which arises from their axil. It is rare to see a movement of the whole of a compound leaf, when its individual portions fold together ; such a movement is seen, however, in the Mimosce. The variety of positions assumed in sleep by the subdivisions of compound leaves is very considerable, and need not be here enumerated : the phenomenon is best exhibited by the Le-guminosce and the Oxalide\u00e6.\nOf the causes of this phenomenon, little can be definitely stated. They are not to be looked for solely in the operation of external physical agents, such as light, heat, and moisture ; for it can be easily shown that the changes in question cannot be thus accounted for, without attributing to the plants by which it is exhibited a tendency to such periodical manifestations inherent in their own constitution. Thus, when sensitive plants are confined in a dark room, their leaflets periodically fold and open as usual ; the periods, however, being somewhat lengthened. On the other hand, when exposed to continued light, the periodical folding and unfolding still occurs, but the periods are shortened. And when the plants are exposed to strong lamplight by night, and excluded from all light by day, their periods of sleep become extremely irregular for a time, but in the end the plants generally close their leaves during the day and open them at night. No such modifications can be induced, however, in the Oxalide\u00e6; their periods of opening and closing their leaves being unaltered by light, darkness, or by the disturbance of the natural sequence of the two. In the same manner it may be proved that these movements cannot be laid to the account of changes of temperature; for it appears from the experiments of De Candolle, that they continue to take place in plants exposed to various degrees of temperature, as well as in those left in air, provided that the heat or cold be not sufficient to injure the health of the plants. And by the same method of exclusion, they can be shown not to be dependent upon variations in the amount of circumambient moisture ; since they continue equally well, c\u00e6teris paribus, when plants are kept in stoves the humidity of whose atmosphere is uniform, and in some cases even when the plants are entirely immersed in water. We must conclude, then, that although the exact time of the occurrence of the phenomenon may be liable to modification from the influence of external agents, its performance is essentially independent of them, aud must be referred to causes inherent in the plant itself.\nThe periodical closing offlowers is a change which is obviously analogous to the sleep of leaves. Many flowers only expand themselves once, and speedily wither. Even in this case, however, there is often considerable regularity in the time of expansion, indicating periodicity. But in the flowers which remain fresh for some days, some degree of alternation between closure and expansion may be gene-\nrally discerned. There is no definite relation, however, between the sleep of flowers and that of leaves ; for they may be united in the same individuals, or be exhibited separately in different species of the same genus. Among other curious examples which show the absence of connection between the two classes of phenomena, is one cited by De Candolle from Berthollet; the subject of it being an Acacia cultivated in the garden at Orotava, in which the leaves closed at sunset, but the flowers then expanded, their numerous stamens raising themselves up like tufts of feathers, so as to become conspicuous ; whilst in the morning, when the leaflets assumed their diurnal position, the filament? relaxed so that the bunches of stamens gave to the flowers the appearance of floss-silk, and the flowers themselves partly closed together.\nIt has been ascertained by Meyen, that, by the action of artificial light and darkness, the usual hours for opening and closing may be changed in flowers as well as in leaves. Thus he found that after passing two days in a room from which external light was excluded, but which was lighted by four Argand lamps, the flowers of Ipom\u0153a purpurea, which naturally open during the night, expanded in the morning ; whilst those of Oxalis tetraphylla, at the end of the fourth day of artificial illumination, opened in the evening, instead of at their usual morning hour.\nPeriodicity of Sleep. \u2014 There can be little doubt that a tendency to occasional repose is inherent in the constitution of every animal possessed of a sensorial apparatus; and that this disposition is so arranged as to correspond in its periodical recurrence with the diurnal revolution of the earth. Although we are accustomed to think that \u201c night is the time for sleep,\u201d and although, in our own case and in that of most other animals, darkness and silence favour repose, yet it must be borne in mind that there are many tribes of animals whose period of activity is the very same with that during which most others are wrapped in slumber. Thus, among lepidopterous insects, we find the activity of the greater part of the butterflies to be diurnal, that of the sphinges to be crepuscular, and that of the moths to be nocturnal. So among the insectivorous birds, we find the diurnal swallow replaced during the night by the goatsucker (or night-jar) ; whilst the insectivorous bats are most active during twilight. Among the raptorial birds, again, we find the whole tribe of owls, with only one or two exceptions, to be either nocturnal or crepuscular in their activity. And among carnivorous animals we meet with a similar diversity. As a general rule, the vegetable-feeders of all tribes are diurnal in their activity, taking their repose at night. The nocturnal predaceous animals take then-repose during the day ; and those whose period of activity is the twilight, sleep partly by night and partly by day.\nNotwithstanding this variety as to the periods of sleep and activity, the complete x x 4","page":679},{"file":"p0680.txt","language":"en","ocr_en":"680\tSLEEP.\ncycle in every case is fulfilled in twenty-four hours ; and this uniformity in their recurrence would seem to indicate either an entire and invariable dependence on external agencies, or else a periodical tendency to sleep, inherent in the animal kingdom, and corresponding with the cycle of day and night. The experience of the human species seems to be decisive in favour of the latter view.\nThere is, among all tribes of mankind, a general uniformity in the periods of slumber and activity, which is scarcely inferior to that observable among the lower animals; yet we find reason to believe that this periodicity is a law of our own organic constitution, for it is quite certain that it cannot be seriously departed from without injury to the system, and that, even where light and warmth are continuous through the whole range of the twenty-four hours (as during the summer in arctic regions), the same periodical desire for sleep manifests itself, resistance to which is prejudicial to the health. As Dr. Whewell justly remarks*\u2014\u201c No one can doubt that the inclination to food and sleep is periodical, or can maintain, with any plausibility, that the period may be lengthened or shortened without limit. We may be tolerably certain that a constantly-recurring period of forty-eight hours would be too long for one day of employment and one period of sleep, with our present faculties ; and all whose bodies and minds are tolerably active will probably agree, that, independently of habit, a perpetual alternation of eight hours up and four in bed would employ the human powers less advantageously and agreeably than an alternation of sixteen and eight.\u201d We may remark, however, that when the habit has been once acquired, the shortening of the cycle is probably not so injurious as its extension. We know by experience that the habitual attempt to sustain an uninterrupted activity during more than sixteen or eighteen hours at a time, is either unsuccessful, or, if successful, is very wearing to the system. On the other hand, the experience of seamen who kept \u201c watch and watch \u201d during long voyages without any obvious injury to their health, indicates that if the due amount of sleep be obtained within every twenty-four hours, the division of the cycle is not attended with any prejudicial effect. On the whole, we may conclude with Dr. Whewell, that, \u201c when we have subtracted from the daily cycle of the employments of men and animals, that which is to be set down to the account of habits acquired, and that which is occasioned by extraneous causes, there still remains a periodical character, and a period of a certain length, which coincides with, or at any rate easily accommodates itself to, the duration of the earth\u2019s revolution.\nCauses of Sleep. \u2014 The most potent of all the causes of sleep, which is capable of acting by itself, when in sufficient intensity, in opposition to the most powerful influences tending to the continuance of wakefulness, is the condition * Bridgewater Treatise, p. 40.\nof the nervous system induced by its protracted functional activity. Sleep may thus come on in the midst of the roar of cannon, and this not merely in persons accustomed to the noise, but in those who have never previously experienced it. Thus it is on record that during the heat of the battle of the Nile, some of the boys who were over-fatigued fell asleep on the deck. We have known a listener to an orchestral performance drop off in slumber during the noisiest part of the grand finale. Again, the continued demand for muscular activity is not incompatible with the access of sleep. During fatiguing marches, as in the retreat to Corunna, it has been repeatedly noticed that whole battalions of infantry have slumbered whilst in motion ; muleteers frequently sleep on their mules, coachmen on their boxes, and post-boys on their horses ; and factory children, before the shortening of the hours of work, were often known to fall asleep whilst attending to their machines. Bodily pain, again, yields before the imperative demand occasioned by the continued exhaustion of the powers of the sensorial centres. Of this the medical practitioner has frequent illustrations. It is well known, too, that the North American Indians, when at the stake of torture, will go to sleep on the least remission of agony, and will slumber until the fire is applied to awaken them. It is related that Damiens slept during his protracted tortures upon the rack ; and that this having been prevented by the constant renewal of fresh torments, he spoke of the want of sleep, a little before the termination of his existence, as the most dreadful of all the sufferings he had endured. That the strongest voluntary determination to remain awake is forced to give way to the demand for sleep produced by the exhaustion of nervous power, must be within the experience of every one.\nIt does not appear to be of any consequence whether this exhaustion is produced by the active exercise of volition, emotion, reflection, or simple sensation. In all alike the sensorial centres must participate; by all alike, therefore, must their nervous substance be subjected to that disintegration which cannot proceed beyond a certain point without either being repaired by sleep, or producing a state of exhaustion which becomes fatal. Nevertheless, we find that the involuntary continuance of mental activity is unfavourable to access of sleep, so as to oppose the action of other predisposing influences ; and such persistence will be found to be especially difficult to check in cases in which the feelmgs are concerned. The activity of the purely intellectual operations, which can be suspended at any moment, provided the feelings be not interested in their continuance, predisposes to sleep instead of preventing it. But the desire to work out a result, or to complete the survey of a subject, is an emotional state which induces restlessness, remaining active until it is gratified. So, again, anxiety or distress is a most frequent cause of wakefulness ; the ex-","page":680},{"file":"p0681.txt","language":"en","ocr_en":"SLEEP.\n681\ndtementof the feelings keeping up aforced state of mental activity, which no voluntary effort can subdue. The state of suspense is in most persons more difficult to bear with equanimity, and is more opposed to the access of sleep, by the continual perturbation which it induces, than the greatest joy or the direst calamity when certainty has been attained. Thus it is a common observation that criminals under sentence of death sleep badly so long as they entertain any hopes of a reprieve ; but as soon as they are satisfied that their sentence will be certainly carried into execution, they usually sleep more soundly,\u2014and this even on the very last night of their lives. That the continued excitement of the feelings, whilst producing an indisposition to sleep, really occasions as great a demand for it in the system as is produced by the most active exercise of the intellectual powers, is evident from the very exhausting effects of its protraction ; which necessitate a long period of tranquillity for restoration to health.\nAmong the most powerful of the predisposing causes to sleep, is the absence of sensorial impressions : thus darkness and silence usually conduce to repose ; and the cessation of the sense of muscular effort, which takes place when we assume a position that is sustained without it, frequently acts as the complement of all other influences. There are cases, however, in which the continuance of an accustomed sound is necessary instead of positive silence, the cessation of the sound being a complete preventive of sleep. Thus it happens that persons living in the neighbourhood of the noisiest mills or forges cannot sleep elsewhere ; and when, to induce repose in illness, the mill or the forge has been stopped, the cessation of the sound only occasions more obstinate wakefulness. Such instances, perhaps, fall within the next category of predisposing causes, \u2014 namely the monotonous repetition of sensorial impressions. Every one knows how efficacious a provocative of sleep is the droning voice of a heavy reader, especially when his subject is equally prosaic. The ripple of the calm ocean upon the shore, the murmur of a rivulet, the sound of a distant waterfall, the rustling of foliage, the hum of bees, and similar monotonous impressions upon the auditory sense, are usually found to induce sleep ; and Boerhaave relates, that being desirous of procuring sleep for one of his patients troubled with obstinate insomnia, he directed a brass pan to be so placed as to receive a succession of drops of water, the sound of which had the desired effect. A lulling influence, however, is not universally thus produced ; for we have known a case in which sleep was altogether kept away by the sound of dropping water, which seems to have occasioned a state of emotional excitement. Not only is the repetition of auditory impressions provocative of sleep ; uniform succession of gentle movements has a similar effect upon the sensorium through the sense of vision. The sleep thus induced, however, is usually characterised by\ncertain peculiarities which will be described hereafter.\u2014 The recurrence of impressions received through the sense of touch has the same effect. Thus Dr. Elliotson says*,\u2014 \u201c I know a lady who often remains awake in spite of every thing, till her husband very gently rubs her foot ; and by asserting to a patient my conviction that the secret of an advertising hypnologist whom I allowed to try his art upon the sleepless individual, and which he did for a time successfully, was to make him gently rub some part of his body till he slept, he confessed this to be the fact.\u201d The rocking of the infant\u2019s cradle, or the gentle swaying of the body backwards and forwards in the arms, are predisposing causes of sleep well known to nurses.\nIn these and similar cases, the influence of the impressions would seem to be exerted in withdrawing the mind from the consciousness of its own operations, the loss of which, as we shall presently point out, is the transition-step of the passage into complete unconsciousness. The reading of a dull book acts in the same mode. There is a monotony of sensorial impressions, the eyes wandering on from line to line and from page to page, without any mental interest in the sensations received ; and if the voluntary effort of attention be intermitted, the thoughts pass off' along their own spontaneous train, whilst the sensorial centres are left free to the soporific influence of monotony.\nThe foregoing are the chief causes of sleep, which operate directly through the sensorial organs themselves. We have now to consider those whose action is indirect, being exerted primarily on the organic functions. Of these the first in order of importance are those which produce increased pressure of blood within the vessels of the encephalon. Thus the assumption of the recumbent position operates in this method as a powerful predisponent to sleep, as well as by rendering all muscular effort unnecessary for the maintenance of the position of the body. To this cause again we are probably to attribute, in great part at least, the drowsiness which succeeds a full meal, the pressure within the encephalic vessels being increased by the pressure of the distended stomach upon the vessels of the abdomen ; but the circulation of imperfectly assimilated matter in the blood may possibly concur in the production of the result. The influence of pressure is most characteristically seen in cases of gradual effusion of blood or of serum from the vessels of the brain : this at first occasions a state of sopor but little different from profound ordinary sleep ; but with the increase of the effusion there is an increase in the depth of the slumber,* the patient can no longer be aroused by sensorial impressions which were at first sufficient to re-excite consciousness, and at last complete coma comes on.f A\n* Physiology, p. 609.\nf Dr. Marshall Hall has advanced the hypothesis, that ordinary sleep is the result of congestion of the brain produced by compression of \u201c certain veins,\u201d","page":681},{"file":"p0682.txt","language":"en","ocr_en":"SLEEP.\n682\nmoderate degree of warmth favours sleep ; perhaps by increasing the energy of the heart\u2019s contractions, at the same time that the walls of the vessels are more relaxed than usual, and thus yield to the impulse. A moderate degree of cold usually has the opposite effect, more especially when the cold is sufficient to produce uneasy sensations. But cold of great severity produces drowsiness, sopor, and even complete coma ; apparently by producing a contracted state of the superficial vessels of the body, and thus occasioning an increase of sanguineous pressure on the encephalic centres. Again, the circulation of blood charged with narcotic substances through the brain, is one of the most powerful of all hypnotising agencies ; and this, again, may produce every gradation of effect, between simple sleep, from which the patient may be easily aroused, and the profoundest coma. One of the most common instances of the operation of this cause, is the production of drowsiness by a deficiency of ventilation ; the carbonic acid which accumulates in the blood, when not freely carried off in the air, having the properties of a powerful narcotic.\nPhenomena of ordinary Sleep. \u2014 The state of perfect sleep is characterised by negative rather than by positive phenomena. As already stated, it essentially consists in the complete suspension of the sensorial powers, and of all those movements in which the nervous system participates, except the simply reflex : with this is conjoined a partial or complete suspension of the functional activity of the cerebrum. According to the more or less potent operation of the soporific causes, will be the degree of insensibility to impressions upon the afferent nerves. No ordinary cause, as we have already shown, is so powerful as previous fatigue. Of the profoundness of the sleep which may result from it, \u2014 in combination, perhaps, with two other agents, warmth, and an atmosphere somewhat charged with carbonic acid,\u2014the following remarkable example may be cited from the \u201cJournal of a Naturalist.\u201d It may be proper to mention that, the correctness of the statement having been called in question, it was fully confirmed by Mr. Richard Smith, the late senior surgeon of the Bristol Infirmary, under whose care the sufferer had been. \u201c A travelling man, one winter\u2019s evening, laid himself down upon the platform of a lime-kiln, placing his feet, probably numbed with cold, upon the heap of stones, newly put on to burn through the night. Sleep overcame him in this situation ; the fire gradually rising and increasing, until it ignited the stones upon\nby \u201c a state of contraction of certain muscles of the neck.\u201d (See his Observations in Medicine, second series, p. 27.) He does not, however, offer the least proof of this hypothesis, nor does he even name the muscles or veins to which he refers. We presume that the platysma myoides and the external jugular are meant. If so, why should not a slight compression of the vein by any other means have the effect of producing sleep at will?\nwhich his feet were placed. Lulled by the warmth, the man slept on ; the fire increased until it burned one foot (which probably was extended over a vent-hole) and part of the leg above the ancle entirely off, consuming that part so effectually, that a cinder-like fragment was alone remaining,\u2014and still the wretch slept on! and in this state was found by the kiln-man in the morning. Insensible to any pain, and ignorant of his misfortune, he attempted to rise and pursue his journey, but missing his shoe requested to have it found ; and when he was raised, putting his burnt limb to the ground to support his body, the extremity of his tibia crumbled into fragments, having been calcined into lime. Still he expressed no sense of pain, and probably experienced none, from the gradual operation of the fire, and his own torpidity during the hours his foot was consuming. This poor drover survived his misfortunes in the hospital about a fortnight ; but the fire having extended to other parts of his body, recovery was hopeless.\u201d It may be added that cases are recorded by medico-legal writers, in which defloration of a virgin, followed by conception, has been effected whilst she was in a state of ordinary sleep, rendered unusually profound by previous fatigue ; but such statements are obviously liable to considerable doubt, and scarcely appear entitled to credence.\nBesides the suspension of the sensorial functions, however, there is usually a slight diminution in the activity of the functions of organic life. The heart\u2019s contractions are less frequent, but the pulse is fuller. So likewise the respiratory movements are diminished in number ; but the inspirations are deeper. Less carbonic acid is produced than during a similar bodily inactivity in the waking state. As might be expected from these differences, the amount of heat generated in the body is diminished, and there is much less power of resisting the effects of cold. So remarkable is this abatement, that when the body is exposed to intense cold (as in the well-known attempt of Sir Joseph Banks and Dr. Solander to explore Terra del Fuego), \u201c to sleep is to die.\u201d There would seem, too, to be a diminution in the power of resisting other morbific agencies. Thus all authorities agree that sleeping in a malarious atmosphere is much more liable to engender the diseases produced by it, than spending the same length of time in the same place, but in the waking state. As a general rule, it would seem that the secreting processes go on with diminished activity during sleep ; but to this the cutaneous transpiration is an exception, so that, in debilitated states of the system, a profuse sweating often occurs as soon as the patient falls asleep. From this diminished activity of the organic functions it happens that hunger is not renewed so speedily after sleep as when the same number of hours have been passed in watching ; a fact well known to those who are liable to suffer habitually or occasionally from the want of food. In this","page":682},{"file":"p0683.txt","language":"en","ocr_en":"SLEEP.\n683\nrespect, then, even the ordinary sleep of the warm-blooded animal may be regarded as an incipient hybernation. Some writers have spoken of the organic functions as performed with increased activity during sleep ; a doctrine so inconsistent with obvious facts, that it could never have been sustained except on the basis of a preconceived idea with regard to the antagonism between the relative activity of the functions of organic and animal life, which idea is in itself fallacious. The actual renovation of the nervous and muscular tissues by the nutritive processes, probably takes place with peculiar energy during the functional inactivity of those parts ; but the preparation of the nutritive materials, which is the office of the digestive and assimilative apparatus, seems to go on more slowly during sleep ; and it is quite certain that less oxygen is then taken into the system, and less carbonic acid generated and set free.\nThe access of sleep is sometimes quite sudden ; the individual passing at once from a state of mental activity to one of complete torpor. More generally, however, it is gradual; and is marked by phenomena which are particularly worthy of attention. \u201cWhile the mind remains poised, as it were, between sleep and the opposite condition,\u201d says Dr. Macnish*, \u201c it is pervaded by a strange confusion, which almost amounts to wild delirium ; the ideas dissolve their connection from it, one by one ; those which remain longest behind are faint, visionary, and indistinct ; and its own essence becomes so vague and diluted, that it melts away in the nothingness of slumber ; as the morning vapours are blended with the surrounding air by the solar heat.\u201d In this passage there is an attempt made to depict the result of the loss of that power of voluntary control over the current of thought, the possession of which is the especial characteristic of the human mind in its state of normal activity. It is the complete suspension of this power, as we shall presently see, which, taken in connection with the entire want of sensibility to external objects, constitutes the state of dreaming; and the same suspension,occurring before the mind is altogether withdrawn from connection with the external world, constitutes that curious intermediate state betwixt sleeping and waking, which may readily pass into either condition. Thus, if the torpor of the sensorial centres be allowed to increase, sleep is produced ; but if it be dissipated by some sensory impression of unusual strength, wakefulness is brought back again, a dreamy impression remaining, both of what had been passing in the mind itself, and of that which had been taking place around. Now, it appears to be by suspending the mind\u2019s attention to its own proceedings, and by drawing off the attention of the sensorium from all other impressions upon the organs of sense, that the monotonous sensations already referred to favour the access of sleep. And it may be further affirmed that all the successful plans for vo-* Philosophy of Sleep, p. 21.\nluntarily producing sleep have some such modus operandi ; their success being dependent upon the intentional fixation of the thoughts upon some one class of sensory impressions (as in the method of Mr. Gardner), or upon some very simple and uniform mental process (such as counting, repeating a French or Greek verb, &c.); and when the attention has been once thus fixed, the monotony of the impression serves to retain it there, so that it abandons, as it were, all control over its operations, and allows itself to be gradually wrapped in repose under the influence of that continued recurrence of similar impressions, which seems even more potent as a soporific than the suspension of all sensational stimuli.\nThe gradual loss of consciousness and of voluntary control over the muscular system during the invasion of sleep is thus described by Dr. Macnish : \u2014 \u201cPrevious to the accession of sleep, a feeling of universal lassitude prevails ; this sensation heralds in the phenomena of slumber, and exhibits itself in yawning, heaviness of the eyes, indifference to surrounding objects, and all the characteristics of fatigue. If the person be seated, his head nods and droops, and, in all cases, the muscles become relaxed, and the limbs thrown into that state most favourable for complete muscular inaction. The lying position is, consequently, the best adapted for sleep, and the one which is intuitively adopted for the purpose. The organs of the senses do not relapse into simultaneous repose, but suspend their respective functions gradually and successively ; sight, taste, smell, hearing, and touch, parting with sensation in the order in which they here stand, and gliding insensibly away. In the same manner the muscles do not become simultaneously relaxed ; those of the limbs giving way first, then those of the neck, and lastly the muscles of the spine. Nor do the external senses, on awaking, recover all at once their usual vigour ; we, for some seconds, neither hear, nor see, nor smell, nor taste, nor touch, with our usual acuteness. Ordinary sights dazzle our eyes ; ordinary sounds confuse our ears ; ordinary odours, tastes, and sensations, our nose, our tongue, and our touch : they awake successively, one after another, and not in the same instant.\u201d *\nThe power of being aroused by impressions made upon the organs of sense, is, as already remarked, one of the chief distinctions between sleep and stupor. The strength of the impression requisite to produce this effect depends upon two circumstances, which require separate consideration : first, the profoundness of the slumber; and, second, the relation of the impression to the habitual condition of the mind. It is a familiar fact that most persons are much more easily aroused towards the morning, when the slumbers are lighter, than they are during the early part of the night, when the sleep is more profound. In fact, the spontaneous awakening which takes place when our repose has been sufficient for the restoration of mental Op. cit. p. 22.","page":683},{"file":"p0684.txt","language":"en","ocr_en":"684\nSLEEP.\nvigour, may generally be traced to some sensory impression of a trivial nature, such as the striking of a clock, which would have produced no effect at a previous time. Some persons, however, always sleep so heavily, that they require a strong impression to arouse them, even when they have had an ample allowance of repose. It is through the hearing and the touch that the awakening impressions are ordinarily conveyed ; but either of the other senses may serve as their channel. Thus, although the closure of the eyelids destroys the acuteness of the perception of light, the eyelids are sufficiently transparent to allow of an impression being made by a light of moderate intensity ; so that those who sleep in a room whose window has an eastern aspect, and is not furnished with sufficient means of excluding the sun\u2019s rays, are liable to be aroused by their ingress some time before the natural amount of repose has been taken. So, again, the sleeper may be awakened by unusual odours ; thus the inmates of a burning house are sometimes first aroused by the smell of fire. The introduction of substances possessing a strong taste into the mouth, will also usually put an end to the state of slumber ; but when the slumber is very profound, such substances may be received, and even swallowed, without the sleeper being thereby awakened.\nThe variety of modes in which the operation of sensory impressions on the sleeper is modified by the previous habitual state of mind, is one of the most remarkable points of the whole subject. The general rule is, that habitual impressions of any kind have much less effect in arousing the slumberer, than those of a new or unaccustomed character. An amusing instance of this kind has been related to the author, which, even if not literally true, serves extremely well as an illustration of what is unquestionably the ordinary fact. A gentleman who had taken his passage on board a ship of war, was aroused on the first morning by the report of the morning gun, which chanced to be fired just above his berth ; the shock was so violent, as to cause him to jump out of bed. On the second morning he was again awoke, but this time he merely started and sat up in bed ; on the third morning the report had simply the effect of causing him to open his eyes for a moment, and turn in his bed : on the fourth morning it ceased to affect him at all, and his slumbers continued to be undisturbed by the report as long as he remained on board. It often happens that sleep is terminated by the cessation of an accustomed sound, especially if this be one whose monotony or continuous repetition had been the original inducement to repose. Thus, a person who has been read or preached to sleep, will awake, if his slumber be not very profound, on the cessation of the voice ; and a naval officer, sleeping beneath the measured tread of the watcli on deck, will awake if that tread be suspended. In this latter case, the influence of the simple cessation of the impression will be augmented\nby the circumstance next to be alluded to, which has received too little attention from writers on this subject, but which is of peculiar interest both in a physiological and psychological point of view, and is practically familiar to almost every one.\nThis is, that the influence of sensory impressions is greatly modified by our habitual state of mind in regard to them. Thus, if we are accustomed to attend to these impressions, and our perception of them is thus increased in acuteness, we are much more easily aroused by them than by others which are in themselves much stronger, but of which we have been accustomed to entertain an utter disregard. Thus, most sleepers are aroused by the sound of their own names uttered in a low tone, when it requires a much louder sound of a different description to produce any manifestation of consciousness. The same thing is seen in comatose states ; a patient being often capable of being momentarily aroused by shouting his name into his ear, when no other sound produces the least effect. The following circumstance, communicated to the author by a naval officer of high rank, is a most apposite illustration of this principle. When a young man, he was serving\"as signal-lieutenant under Lord Hood, at the time when the French fleet was confined in Toulon harbour ; and being desirous of obtaining the favourable notice of his commander, he devoted himself to his duty \u2014 that of watching for signals made by the lookout frigates \u2014 with the greatest energy and perseverance, often remaining on deck nineteen hours out of the twenty-four, with his attention constantly directed towards this one object. During the few hours which he spent in repose, his sleep was so profound, that no noise of an ordinary kind, however loud, would awake him ; and it used to be a favourite amusement with his comrades, to try various experiments devised to test the soundness of his sleep. But if the word \u201c signal \u201d was even whispered in his ear, he was instantly aroused, and fit for immediate duty.\nIt is not requisite, however, that the sound should be one habitually attended to during the hours of watchfulness ; for it is sufficient if it be one on which the attention has been fixed as that at which the slumberer is to arouse himself. Thus the medical man, even in his first profound sleep after a fatiguing day\u2019s work, is aroused by the first stroke of the clapper of his night-bell ; and to those who are accustomed to rise every morning at the sound of an alarum-clock, the frequency and regularity of the occurrence do not diminish, but rather increase, the readiness with which it produces its effect, provided that the warning be promptly obeyed. On this usually depends the efficiency of the awakening sound ; if it be disregarded as a thing to which there is no occasion to give heed, it very soon ceases to produce any effect, the entire peal not being sufficient to awake the sleeper; whilst, on the other","page":684},{"file":"p0685.txt","language":"en","ocr_en":"SLEEP.\nhand, the first stroke is enough to break the repose of him who is impressed with the effectual desire of profiting by the warning. And thus it may happen that, of two persons in the same room, either shall be at once aroused by a sound which produces no disturbance in the slumbers of the other.\u2014 The influence of habitual attention is shown as much in the effect produced by the cessation, as in that of the occurrence, of sensory impressions. Thus in the case of the naval officer aroused by the suspension of the measured tread of the watch over his head, the knowledge possessed during the waking state that this suspension is either an act of negligence which requires notice, or indicates some unusual occurrence, doubtless augments the effect which the discontinuance of the sound would of itself produce.\nPutting aside the awakening influence of external impressions, the period of natural termination of the slumber is greatly influenced by habit. Thus, many persons who are accustomed to rise at a particular hour, wake regularly at that hour, whether they have gone to rest early or late ; so that the act of spontaneously awakening is no proof that the desirable amount of repose has been obtained. But what is more remarkable is, that many individuals have the power of determining, at the time of going to rest, the hour at which they shall rise, so as to awake from a profound sleep at the precise time fixed upon. In others, however, the desire to rise at a particular hour only induces a state of restlessness throughout the night, destroying the soundness of the slumbers : the individual awakes many times in the night, with the belief that the hour is past, and very possibly oversleeps it after all, the system being worn out by the need of repose.\nThe Amount of sleep required by man is affected by many conditions, especially age, temperament, habit, and previous exhaustion; so that no general rule can be laid down upon the subject. The condition of the foetus in utero may be regarded as one of continual slumber ; the energy of the organic functions being entirely directed to the building-up of the organism, whilst the apparatus of animal life is completely secluded from all the stimuli which could arouse it into activity. On its first entrance into the world, the infant continues to pass the greater part of its time in slumber ; and this is particularly to be noticed in cases of premature birth,\u2014the seven months\u2019 child seeming to awake only for the purpose of receiving food, and giving but little heed to any external objects when its internal cravings are satisfied; and even the eight months\u2019 infant being considerably less alive to sensory impressions, than one born at the full time. During the whole period of infancy and childhood, it is necessary for the development of the body that the constructive operations should be more energetic than the destructive; and, accordingly, we find that the period of sleep, during which the former take place without hindrance, is longer in proportion to\n685\nthe waking state, during which the latter ara in play, than it is when full growth has been obtained.*\nAs age advances, the necessity for very rapid nutrition gradually diminishes, in consequence of the progressive approach to complete development ; and when the adult period has been attained, it is not requisite that the constructive processes should do more than balance the destructive. The amount of sleep requisite for this purpose, therefore, gradually diminishes, until it is reduced to (at most) one-third of the cycle of twenty-four hours, It is to be noticed that the sleep of children and young persons is not only longer than that of adults, but is also more profound. On the other hand, as age advances, and the bodily and mental activity of the waking state decreases, a smaller amount of sleep suffices ; or, if the slumber be protracted, it is usually less deep and refreshing. It may be noticed, however, that very old persons usually pass a large proportion of their time in sleep, or rather in dozing ; as if, in consequence of the want of energy of their nutritive operations, a very long period of repose is necessary to repair the waste which takes place during their short period of activity. It is stated f that \u201c the celebrated De Moivre slept twenty hours out of the twenty-four; and Thomas Parr latterly slept away by far the greater part of his existence.\u201d The repose of the aged is most apt to take place immediately after taking food ; while they solicit it in vain at that period at which, during the former years of their lives, they had been accustomed to enjoy it.\nThe amount of sleep, again, is much affected by temperament. It will generally be found that a plethoric habit of body, sustained by full diet, predisposes to sleep, provided the digestive powers be in a vigorous condition. Such persons frequently pass nine or ten hours in slumber, and maintain that they cannot be adequately refreshed by less. On the other hand, thin wiry people, in whom the \u201c nervous\u201d temperament predominates, usually take comparatively little sleep, notwithstanding the greater activity of their nervous system when they are awake ; but their slumber, while it lasts, is generally very deep. Persons of \u201c lymphatic\u201d temperament, heavy\n* It is to be remembered, when we compare the condition of the nutritive operations during the period of growth, and after the complete development of the organism, that it is not in the mere amount of accretion that the difference consists. This would be the case if the new matter were merely added to the old, as in the formation of a new layer of wood in an exogenous stem. The growth of the animal fabric requires a continual new development of every part of it, involving a constant change in its materials ; and thus we see that the amount of food required by children, and the quantity of urea, and other products of the disintegration of the tissues set free in their excretions, bear a much larger proportion to those of the adult, than would be inferred from the relative bulk of the body at the two periods, and from its rate of increase during the former.\nf Macnish, op. cit. p. 37.","page":685},{"file":"p0686.txt","language":"en","ocr_en":"686\nSLEEP.\npassionless people, who may be said to live very slowly, are usually great sleepers; but this rather because, through the dullness of their perceptions, they are less easily kept awake by sensorial or mental excitement, than because they really require a prolonged cessation of activity. As they are half asleep during the waking state, so would it appear that the constructive operations must be far from active while they are asleep,\u2014so little do they seem restored by the repose.\nThe amount of sleep, c\u0153teris paribus, required by individuals, is very greatly influenced by habit ; and, contrary to what we might anticipate, we find that the briefest sleepers have usually been men of the greatest mental activity. Thus Frederick the Great and John Hunter are said to have only required five hours\u2019 sleep out of the twenty-four. General Elliot, celebrated for his defence of Gibraltar, is recorded not to have slept more than four hours out of the twenty-four.* Sir Gilbert Blane states -j- that General Pichegru informed him that, \u201c in the course of his active campaigns, he had for a whole year not more than one hour of sleep, on an average, in twenty-four hours.\u201d We suspect that if he had said \u201c one hour of sleep at a time,\u201d he would have been nearer the truth. This we believe to have been the case with regard to the Duke of Wellington during the Peninsular campaigns. Dr. Elliotson saysj, \u201c I heard Baxter, the coachmaker, declare that he never took more than three hours\u2019 sleep during the most active period of his life.\u201d We doubt if it would be possible for any one to sustain a life of vigorous exertion with a smaller allowance than this.\nThe influence of habit is further shown in producing an aptitude for repose, or a readiness to wake, at particular periods. Thus, if a man is accustomed to go to rest at ten o\u2019clock, and to rise at six, he will probably awake at six, even if he have not fallen asleep until twelve. And in like manner, if the morning sleep have been unusually protracted, the desire for sleep will probably return at the accustomed hour in the evening. The influence of habit is further exerted in producing an aptitude for sleep whenever the opportunity is afforded. Thus, the celebrated pedestrian Capt. Barclay, when accomplishing his extraordinary feat of walking 1000 miles in as many successive hours, obtained at last such a mastery over himself that he fell asleep the instant he lay down. And the sleep of soldiers, sailors, and others, who may be prevented from obtaining regular periods of repose, but are obliged to take their rest at short intervals, may be almost said to come at command ; nothing more being necessary to induce it than the placing the body in an easy position, and the closure of the eyes. On the other hand, habit favors the protraction of sleep. This was the case with Quin, the celebrated actor, who could slumber for\n* Macnish, op. cit. p. 34.\nf Medical Logic, p. 83.\nX Physiology, p. 601.\ntwenty-four hours successively ; and with Dr. Reid, the metaphysician, who could take as much food, and afterwards as much sleep, as were sufficient for two days.\nIt is needless to dwell upon the obvious fact, that, other things being equal, the amount of sleep required by man is proportional to the amount of mental exertion put forth during the waking hours ; since this is an obvious result of what has been laid down as the cause of the demand for sleep. It may be remarked, however, that we must not measure the amount of sleep by its duration alone ; since its intensity is a matter of equal importance. The light slumber which is disturbed by the slightest sounds, cannot be as renovating as the profound sopor of those whom no ordinary noise will awake.\nThere are certain states of the nervous system in which there is an entire absence oj sleep ; and this may continue for many days, or even weeks or months. Insomnia is, for instance, one of the characteristics of acute mania, and may also exist in various forms of monomania. It is usually, also, one of the symptoms of incipient meningeal inflammation. And it may constitute a specific disease in itself. In all these cases, however, the preponderance of the destructive processes over the constructive manifests itself, sooner or later, in the exhaustion of the mental and bodily powers. Thus mania, when prolonged or frequently occurring, subsides into dementia. When meningitis (or rather inflammation of the surface of the hemispheric ganglia) is fully developed, a rapid disintegration of nervous matter takes place, as indicated by the large amount of alkaline phosphates in the urine.* The same would probably be detected in cases of idiopathic insomnia; which state, if it continue for any length of time, is sure to be followed by a great sense of wretchedness and prostration, frequently accompanied by continual restlessness. Such effects, too, in a less aggravated degree, result from habitual deficiency of sleep; whether this results from emotional excitement, which keeps repose at bay, or from a voluntary determination to keep the intellect in activity. This is a very common occurrence among industrious students, who, with a laudable desire for distinction, allow themselves less than the needed quantum of repose. Headache, tension, heat, throbbing, and various other unpleasant sensations in the head, give warning that the brain is being overtasked; and if this warning be not taken, sleep, which it was at first difficult to resist, becomes even more difficult to obtain ; a state of general restlessness and feverish excitement are induced ; and if, in spite of this, the effort be continued, serious consequences, in the form of cerebral inflammation, apoplexy, paralysis, fever, insanity, or loss of mental power, more or less complete, are nearly certain to be induced. Some individuals can sustain such an effort much longer than others, but it is a great mistake to suppose that they are not\n* See Dr. Bence Jones in Phil. Trans. 1846.","page":686},{"file":"p0687.txt","language":"en","ocr_en":"SLEEP.\n687\nequally injured by it ; in fact, being possessed with the belief that they are not suffering from the exertion, they frequently pi'otract it until a sudden and complete prostration gives a fearful demonstration of the cumulative effects of the injurious course in which they have been persevering. Those, consequently, who are earlier forced to give way, are frequently capable of accomplishing more in the end.\nIn regard to the degree of protraction of sleep which is consistent with a healthy state of the system in other respects, it is difficult to speak with certainty. Of the numerous well-authenticated instances on record*, in which sleep has been continuously prolonged for many days or even weeks, it is enough here to state that they cannot be regarded as examples of natural sleep ; the state of such persons being more closely allied to hysteric coma. An unusual tendency to proper sleep generally indicates a congested state of the brain, tending to apoplexy ; and it has been stated that apoplexy has been actually induced by the experimental attempts to ascertain how large a proportion of the diurnal cycle might be spent in sleep. This effect may be readily explained, if we regard it as a general law of the capillary circulation, that its rate is increased by functional activity, and diminished by inactivity ; for whilst congestion of the brain arising from other causes will tend to produce sleep, through the augmented pressure it occasions, mental inactivity, if encouraged and persisted in, will itself tend to produce congestion.\nThus, on either side, inattention to the dictates of Nature in respect to the amount of sleep required for the renovation of the system, becomes a source of disease, and should therefore be carefully avoided.\nDREAMING.\nWe have hitherto spoken of sleep in its most complete or profound form, \u2014 that is, the state of complete unconsciousness. But with the absence of consciousness of external things, there may be a state of mental activity, of which we are more or less distinctly conscious at the time, and of which our subsequent remembrance in the waking state also varies in completeness: the impression being sometimes vivid, definite, and enduring; sometimes shadowy and evanescent ; sometimes not amounting to more than the feeling that we have dreamed ; and sometimes not even this being preserved, notwithstanding that there may be positive assurance that the sleep has been thus disturbed. This state, known as dreaming, is one of the highest interest to the psychologist; but the limits imposed upon us forbid our doing more than enumerate its leading phenomena.\nThe chief feature of the state of dreaming appears to be, that there is an entire absence of voluntary control over the current of thought; so that the principle of suggestion\u2014one thought\n* Such, for example, as that of Samuel Chilton (Phil. Trans., 1694), and that of Mary Lyall (Trans, of Roy. Soc. of Edinb., 1818).\ncalling up another, according to the laws of association\u2014has unlimited operation. Sometimes the train of thought thus carried on is remarkably consistent. We witness scenes that have occurred during our waking hours, and seem to hear, see, move, talk, and perform all the actions of life. We may experience every kind of mental emotion, and may even compare, reason, judge, and will, during our sleep ; and our reasoning processes have frequently a remarkable clearness and completeness, \u2014 the data on which they are founded being supposed to be accurate. This consistency is usually the greatest, when the mind simply takes up a train of thought on which it had been engaged during the waking hours, not long previously ; and it may even happen that, in consequence of the freedom from distraction occasioned by the suspension of ordinary sensations, the intellectual operations may be carried on during sleep with uncommon vigour and success. Thus, to name only two instances, Condorcet saw, in his dreams, the final steps of a difficult calculation, which had puzzled him during the day ; and Condillac states that, when engaged with his \u201c Cours d\u2019Etude,\u201d he frequently developed and finished a subject in his dreams, which he had broken off before retiring to rest.\nThe imagination, equally with the reasoning processes, sometimes moves in a consistent course. Thus, Dr. Good relates the case of a friend who composed a little ode of about six stanzas, and set the same to agreeable music, in his sleep, the impression remainingso vividly that he was able to write down both the words and music on awaking in the morning ; and Coleridge relates of himself that his fragment, entitled \u201c Kubla Khan,\u201d was composed during sleep, which had come upon him whilst reading the passage in \u201c Purchas\u2019s Pilgrimage \u201d on which the poetical description is founded, and was written down immediately on awaking. The images, he says, \u201c rose up before him as things, with a parallel production of the correspondent expressions, without any sensation or consciousness of effort.\u201d It would seem necessary, in most cases of this kind, that the results should be committed to paper immediately on waking, before the train of thought, continued from the dream, has been disturbed by any other. Thus, Coleridge tells us that, after having written for some little time, he was interrupted by a person on business, who continued with him above an hour; and on the departure of his visitor, he found, to his surprise and mortification, that \u201cthough he still retained some vague and dim recollection of the general purport of the vision, yet, with the exception of some eight or ten scattered lines and images, all the rest had passed away like the images on the surface of a stream into which a stone had been cast ; but, alas ! without the after-restoration of the latter.\u201d In other cases, a strong general impression of what has passed through the mind in sleep may remain on waking, without power of recalling the particulars. This was the case in the well-known instance of the musician Tartini, to whom the","page":687},{"file":"p0688.txt","language":"en","ocr_en":"688\nSLEEP.\narch-fiend appeared in his sleep, and was challenged by him to a trial of skill : the dreamer lay entranced by the transcendent performance of his visitor, which surpassed anything he had ever heard or conceived ; on awaking, however, he could not reproduce the succession of notes, although he immediately seized his violin, and endeavoured to do so ; but, under the strong general impression of what he had heard, he produced a new composition, which retains the name of the \u201c Devil\u2019s Sonata.\u201d\nBut, although dreams may possess a remarkable coherence, whether as regards pro-cessses of reasoning, or the new combinations of the imagination, the general fact is, that such coherence is altogether wanting, and that there is a complete incongruousness in the thoughts and images which pass through our minds. All probabilities, and even possibilities of \u201c time, place, and circumstance \u201d are violated ; the dead pass before us as if alive and well ; even the sages of antiquity hold personal converse with us ; our friends at the antipodes are brought upon the scene, or we ourselves are conveyed thither, without the least perception of distance ; and the strangest combinations of reality and fancy are presented, either as objects passing before our consciousness, or as affecting our own condition. But of this incongruity we are seldom in the least aware. We are not capable of testing the probability or possibility of the phenomena by our ordinary experience. And, as a consequence of this, nothing surprises us in dreams ; the feeling of surprise being the result, and indeed the measure, of our perception of the unlikelihood of a phenomenon. Not only is there usually a want of congruity in the intellectual processes, but a great disturbance in the ordinary play of the emotions. \u201c Thus, in our dreams we may walk on the brink of a precipice, or see ourselves doomed to immediate destruction by the weapon of a foe or the fury of a tempestuous sea, and yet feel not the slightest emotion of fear ; though, during the perfect activity of the brain, we may be naturally disposed to the strong manifestation of this feeling. Again, we may see the most extraordinary object or event without surprise, perform the most ruthless crime without compunction, and see what in our waking hours w ould cause us unmitigated grief, without the smallest feeling of sorrow.\u201d * This is, however, by no means uniformly the case. In fact, our emotions in the dreaming state are often highly wrought ; and it frequently seems that the excitement of some particular emotion gives the direction to the whole train of thought, and causes it to possess an unusual coherence and probability. This is most remarkable, perhaps, when the emotion in question has greatly occupied the mind in the previous waking hours. Thus, a female, whose husband is at sea, and for whose safety she naturally feels anxious, especially in stormy weather, is very apt to dream of shipwreck and all its at-* Prof. Wheatstone, quoted in Elliotson\u2019s Physiology, p. 621.\ntendant circumstances ; or, on the other hand, a man in love dreams of his mistress, of married life, and of its various enjoyments. Even here, however, the congruity is frequently interrupted by the intervention of some strange occurrence; the oddity of which may be perceived by the dreamer as being discordant, not with the intellectual but with the emotional state.\nIn simple dreaming, as there is a loss of voluntary control over the current of thought, so is there an absence of control over the muscular system. Movements expressive of emotions, however, may still take place, and may afford to the by-stander an indication of what is passing in the mind of the dreamer. The indications of fear, horror, or disgust, or of hope, rapture, or desire,\u2014laughter or weeping, smiles or frowns,\u2014 may all display themselves, when there is an absolute cessation of all voluntary movements. This is remarkably the case in attacks of incubus, or nightmare ; in which the dreamer is oppressed by intolerable distress, from which he makes vain attempts to free himself. His distress may be expressed by moans, or by the agitation of his countenance ; but none of his fancied efforts are indicated by any respondent movements. This condition may subside into a state of tranquil slumber, or the agitation may increase to such a pitch as to awake the sufferer ; and as the first act of the waking state is usually to cry out or kick violently, it has been supposed that the return of volition has been the cause, instead of being the effect, of the cessation of the oppressive dream. There are cases, however, in which the dreamer executes movements in consonance with ideas passing through his mind, \u2014 such as W'ould, in the waking state, be termed voluntary ; but these must be considered as belonging rather to the category of somnambulism than to that of simple dreaming.\nThe direction of the current of thought in dreaming is often given by impressions on the organs of sense, which influence the mental operations, by calling up associated ideas, without being recognized and perceived as distinct sensations. Thus, Dr. James Gregory, having applied a hot bottle to his feet on going to bed, dreamt that he was walking up Etna and finding the ground intolerably hot. On another occasion, he dreamt of spending a winter at Hudson\u2019s Bay, and of suffering much distress from the intense frost ; this evidently the consequence of his having thrown off the bed-clothes in his sleep, and of his having been reading, a few days before, a very particular account of the state of the colonies in that country during winter. Dr. Keid, having a badly-dressed blister on his head, dreamt that he was being scalped by Indians ; and a man in a damp bed, that he was being dragged through a stream. A gouty man, when beginning to feel his pain in his sleep, may dream he is on the rack before inquisitors. The sound of music may excite delightful dreams. M. Girou de Buzarein-gues* made some curious experiments on * Journal de Physiologie, tom. viii.","page":688},{"file":"p0689.txt","language":"en","ocr_en":"SLEEP.\nthis point, and directed at pleasure the character of his dreams. In his first experiment, having allowed the back of his head to be uncovered during sleep, he thought he was at a religious ceremony in the open air ; the custom of the country in which he lived being to keep the head covered excepting on some rare occurrences, among which was the performance of religious ceremonies. On waking he felt cold at the back of the neck, as he frequently had when present at the real ceremonies. He repeated the experiment in two days, with the same result. In a third experiment, he left his knees uncovered, and dreamt that he was travelling at night in the diligence ; and ail travellers know, he observes, that it is chiefly at the knees that they feel cold when travelling by that conveyance at night. The very remarkable degree in which this influence of external impressions is exerted, when sleep is being induced by the agency of certain narcotics, will be presently noticed. By the use of the term \u201c external \u201d is here meant that which is external to the mind itself. The dream may originate in impressions derived from any part of the bodily frame. Thus we find that indigestion is a very common cause of nightmare, and that an irritable state of the genital apparatus provokes lascivious dreams. When the external impressions are recognized as sensations, and the dreamer\u2019s current of thought completely follows their guidance, so that even the meaning of spoken language is appreciated, the condition approximates to that of Somnambulism.\nOne of the most remarkable of all the peculiarities of the state of dreaming, is the rapidity with which trains of thought pass through the mind ; a dream in which a long series of events has seemed to occur, and a multitude of images has been successively raised up, being often certainly known to have occupied but a few minutes or even seconds. This is best seen in those cases in which the dream has obviously originated in some sensory impression, which has also had the effect of arousing the sleeper. A very interesting example of this, in which a similar dream was produced in two individuals, husband and wife, from the same cause, came within the knowledge of the late Dr. James Gregory. It happened when the public mind was much excited in regard to the alarm of French invasion, and the gentleman who was the subject of it was himself a zealous member of the Edinburgh volunteer corps.. Whilst asleep, between two and three o\u2019clock in the morning, he dreamt of hearing the signal gun: he was immediately at the Castle, witnessed the proceedings for displaying the signals to alarm the country, and saw and heard a great bustle over the town, from troops and artillery assembling, especially in Princes Street. At this time he was roused by his wife, who awoke in a fright, in consequence of a similar dream, connected with much noise and the landing of the enemy, and concluding with the death of a particular friend of her husband\u2019s, who had\nVOL. IV.\n689\nserved with him as a volunteer. The origin of this remarkable occurrence was ascertained, in the morning, to be the noise produced in the room above by the fall of a pair of tongs. How long the dream had continued in this instance is uncertain ; evidently not for a period in the least comparable to that required for the actual occurrence of the events that had passed through the mind of each ; and it is probable, from many similar cases, that the lady was awoke by the noise rather than by the fright. Thus a gentleman dreamt that he had enlisted as a soldier, joined his regiment, deserted, was apprehended, carried back, tried, condemned to be shot, and at last led out for execution. After all the usual preparations, a gun was fired ; he awoke with the report, and found that a noise in an adjoining room had both produced the dream and awoke him. The same feeling of duration, arising out of the number of images passing in succession through the mind, is often experienced when we are well assured that the whole duration of our sleep has not exceeded a few moments. We have known a clergyman fall asleep in his pulpit during the singing of the psalm before sermon, and awake with the conviction that he must have slept for at least an hour, and that the congregation must have been waiting for him ; but on referring to his psalm-book, he has been consoled by finding that his slumber has lasted no longer than during the singing of a single line. There would not seem, in fact, to be any limit to the amount of thought which may thus pass through the mind of the dreamer, in an interval so brief as to be scarcely capable of measurement ; and this view is confirmed by the circumstance, now well attested, that it is a common occurrence in drowning for the whole previous life of the individual to be presented instantaneously to his view ; with its every important incident vividly impressed on his consciousness, just as if all were combined in a picture, every part of which could be taken in at a glance. This, again, is connected with the fact that the operation of the associative principle may reproduce in dreams the remembrance of facts long since forgotten in the waking state. Such, however, is by no means peculiar to the state of dreaming ; for in the waking state we often retrace involuntarily and unexpectedly something which we have in vain attempted to recall at will, and which might be said to have passed from our mental grasp.\nFrom the foregoing and other similar facts it has been argued, that all our dreams really take place in the act of falling asleep or of awaking ; so that even when we fancy that we have been dreaming all night, our unconsciousness has been really complete, except at these momentary intervals. That this doctrine cannot be altogether true is obvious from the fact, that we can frequently detect the character of a dream, and even in some degree trace its progress, by the expression of the sleeper\u2019s countenance ; so that dreams certainly may occupy time, and occur during Y Y","page":689},{"file":"p0690.txt","language":"en","ocr_en":"690\tSLEEP.\nordinary sleep. On the other hand, it may be freely admitted that the apparent duration of our dreams does not afford the least measure of the time they have really occupied ; and that it is probable that even when our sleep has seemed most disturbed by them, we have really passed a larger portion of the night in a state of complete unconsciousness than the mere impression left by our dreams would allow us to believe. But it has been questioned by some, on the other hand, whether there is ever such a state as that of complete unconsciousness. It is affirmed that the mind can never be entirely inactive ; and that every body, in fact, does dream throughout the period of sleep, although the dreams may not be remembered in the waking state. This statement is rather based upon the hypothesis with which it commences, than upon any positive facts ; and as it requires us to give up the simple teachings of ordinary experience, for the reception of a mere metaphysical dogma, the physiologist need not concern himself with the discussion.\nOn the whole, it maybe said that dreaming indicates that sleep is imperfect ; and this view harmonises with the fact that between dreaming and the waking state there are various connecting gradations. Thus, reverie or day-dreaming differs from the dreaming of the sleeper, not so much in the condition of the mind and its instrument the cerebrum, as in that of the sensorium, which is not so completely withdrawn in the former case, as it is in the latter, from the consciousness of external impressions. In sleep, on the other hand, the dreamer may have a consciousness of the unreality of the images that arise in his mind, and may even make a voluntary and successful effort to prolong them if agreeable, or to dissipate them if unpleasing ; thus evincing the presence of that power of control over the current of thought, the want of which is one of the best characteristics of ordinary dreaming, as it is also of insanity, and indicating, therefore, an unusual approximation to the vigilant condition,\nThe action of narcotics on the nervous system presents many curious illustrations of the foregoing statements regarding the nature and phenomena of dreaming. There are some which have the power of inducing every condition intermediate between an unusual activity of the thoughts and a state of complete stupor, according to the dose taken. This is the case to a certain degree with opium ; but still more decidedly with the extract of Cannabis Indien, a preparation of whch, known under the names of Hachisch and Dawamesc, is much used in the East for the production of a species of agreeable intoxication. _ The first effect of a dose of this substance is usually to produce a moderate exhilaration of the feelings and an unusual activity of the intellectual powers ; but this activity gradually frees itself from voluntary control. The individual feels himself incapable of fixing his attention upon any subject ; his thoughts being\ncontinually drawn off by a succession of ideas which force themselves (as it were) into his mind, without his being able in the least to trace their origin. These speedily occupy his attention, and present themselves in strange combinations, so as to produce the most fantastic and impossible creations. By a strong effort of the will, however, the original thread of the ideas may still be recovered, and the interlopers driven away. These lucid intervals successively become of shorter duration, and can be less frequently procured by a voluntary effort ; for the internal tempest becomes more and more violent, the torrent of disconnected ideas increases in power so as completely to arrest the attention, and the mind is gradually withdrawn altogether from the contemplation of external realities, being engrossed by the consciousness of its own internal workings. There is always preserved, however, a much greater amount of self-consciousness than exists in ordinary dreaming ; the condition rather corresponding with that just referred to, in which the sleeper knows that he is dreaming. The succession of ideas has at first less of incoherence than in ordinary dreaming, the ideal events not departing so far from possible realities ; and the disorder of the mind is at first manifested in errors of sense, in false convictions, or in the predominance of one or more extravagant ideas. These ideas and convictions are generally not altogether of an imaginary character, but are called up by external impressions, which are erroneous^ interpreted by the perceptive faculties. The error of perception is remarkably shown in regard to time and space ; minutes seem hours, hours are prolonged into years, and at last all idea of time seems obliterated, and past and present are confounded together as in ordinary dreaming : and in like manner, streets appear of an interminable length, and the people at the other end seem to be at a vast distance. Still there is a certain consciousness of the deceptive nature of these illusions, which, if the dose be moderate, is never entirely lost.\nThe effect of a full dose, however, is at last to produce the complete withdrawal of the mind from any distinct comprehension of external things ; the power of the will over the current of thought is in like manner suspended, and the condition of the mind becomes the same in all essential particulars with that of the ordinary dreamer ; differing in this chiefly, that the feelings are more strongly exerted, and that they still take their tone almost entirely from external impressions. Thus, says M. Moreau*, \u201c It will be entirely dependent on the circumstances in which we are placed, the objects which strike the eyes, the words which fall on our ears, whether the most lively sentiments of gaiety or of sadness shall be produced, or passions of the most opposite nature shall be excited, sometimes with extraordinary violence ; for irritation\n* Du Hachisch et de l\u2019Ali\u00e9nation Mentale, Etudes Psychologiques, p. 67.","page":690},{"file":"p0691.txt","language":"en","ocr_en":"SLEEP.\t691\nshall pass rapidly into rage, dislike to hatred, and the desire of vengeance and the calmest affection to the most transporting passion. Fear becomes terror, courage is developed into rashness which nothing checks, and which seems not to be conscious of danger, and the most unfounded doubt or suspicion becomes a certainty. The mind has a tendency to exaggerate everything, and the slightest impulse carries it along. Those who make use of the hachisch in the East, when they wish to give themselves up to the intoxication of the fantasia, take great care to withdraw themselves from everything which could give to their delirium a tendency to melancholy, or excite in them anything else than feelings of pleasurable enjoyment. They profit by all the means which the dissolute manners of the East place at their disposal. It is in the midst of the harem, surrounded by their women, under the charm of music and of lascivious dances executed by the Almees, that they enjoy the intoxicating dawamesc ; and with the aid of superstition, they find themselves almost transported to the scene of the numberless marvels which the Prophet has collected in his Paradise.\u2019\u2019*\nSOMNAMBULISM.\nOur history of sleep would be incomplete without some account of a state which is closely allied to it, though differing from it in several important particulars. The phenomena of somnambulism are so varied, that it is very difficult to frame any definition capable of including them all ; and we prefer characterising the state by saying that it may be considered as an acted dream,\u2014differing from ordinary dreaming in the two following points. In the first place, the train of thought is more under the direction of sensations derived from without; and, secondly, the muscular system is so completely under the control of the mind, as not merely to give expression to its emotional states, but also to act in respondent to its volitions. As in dreaming, there would seem to be, in true somnambulism, a complete want of voluntary control over the current of thought, but there is not the same degree of mental activity; and in particular the operation of the associative principle is so much more restricted, that there is little or\n* The celebrated oriental scholar, M. Sylvestre de Sacy, appears to have made it pretty plain that our word assassin is derived from Hachischin, in the following manner. It is well known that the term was originally employed in Syria, to designate the followers of the \u201c Old Man of the Mountain,\u201d who were accustomed to devote themselves with blind obedience to the execution of the orders of their chief, sacrificing themselves or others with equal readiness. Their education tended in every way to impress upon them this duty ; and as a reward for its performance, they were promised after death all the sensual pleasures they could imagine,\u2014a foretaste of these being every now and then given to them by intoxicating them with hachisch, in the midst of scenes in which everything was provided to gratify their senses. In this manner, a sort of fanaticism was gradually induced, which rendered them fit agents of the murderous designs of their master.\nnone of that incoherence or incongruity in the ideas brought up, which is so peculiar in ordinary dreaming. On the contrary, reasoning processes are often carried out with extraordinary clearness and correctness; the mind being intently fixed upon them to the exclusion of all other considerations. This exclusiveness, indeed, is one of the most remarkable characteristics of the condition. Whilst the attention of the mind remains fixed upon any object, either perceived by the senses or brought up by the act of conception, nothing else is felt. Thus there may be complete insensibility to bodily pain, the somnambulist\u2019s whole attention being given to that which is passing within the mind. Yet, in an instant, by directing the attention to the organs of sense, the anaesthesia may be succeeded by the most acute sensibility. So, again, when the attention is fixed upon a certain train of thought, whatever is spoken in harmony with it is heard and appreciated by the somnambulist ; but whatever is in discordance with it is entirely disregarded. The character of the intellectual operations partakes of this peculiarity. As just now stated, the reasoning processes are usually accurately and definitely carried on, so that the conclusion will be sound, provided that the data have been correct. Thus, a mathematician will work out a difficult problem, or an orator will make a speech appropriate to a given subject. But the usual defect of the intellectual operations carried on in this condition is, that, owing to their very intensity, the attention is drawn off from the considerations which ought to modify them ; and thus it happens that the result is often palpably inconsistent with the teachings of ordinary experience, and will be admitted to be so by the somnambulist when the former are brought to his mind.\nThe state of somnambulism may pass, on the one hand, into that of ordinary dreaming, so that it is difficult to draw the line between the two. Thus, the ordinary \u201c talking in the sleep\u201d may be referred to one or the other condition, according to the definition of each that we may adopt. In our own arrangement, they fall under the second head : because the vocal movements are expressions of the intellectual processes that are taking place in the mind ; and because, in most cases of this kind, the sleep-talker hears and comprehends what is said to him, provided that this harmonises with what is going on within, and will answer rationally, so as to sustain a conversation. Thus, we knew a young lady at school, who frequently began to talk after having been asleep an hour or two ; her ideas almost always ran upon the events of the previous day ; and if encouraged by leading questions addressed to her, she would give a very distinct and coherent account of them ; frequently disclosing her own peccadilloes and those of her schoolfellows, and expressing great penitence for the former, whilst she seemed to hesitate about making known the latter. To all ordinary sounds, however, she seemed perfectly insensible. A loud noise would awake her, but Y Y 2","page":691},{"file":"p0692.txt","language":"en","ocr_en":"692\nSLEEP.\nwas never perceived in the sleepwalking state; and if the interlocutor addressed to her any questions or observations that did not fall in with her train of thought, they were completely disregarded. By a little adroitness, however, she might be led to talk upon almost any subject; a transition being gradually made from one to another by means of leading questions.\nThe well-known case of the officer, narrated by Dr. James Gregory, is one of the same intermediate class; rather allied, in our apprehension, to somnambulism than to ordinary dreaming. This gentleman, who served in the expedition to Louisburgh in 1758, was in the habit of acting his dreams ; and their course could be completely directed by whispering into his ear, especially if this was done by a friend with whose voice he was familiar; so that his companions in the transport were in the constant habit of amusing themselves at his expense. At one time they conducted him through the whole progress of a quarrel, which ended in a duel ; and when the parties were supposed to be met, a pistol was put into his hand, which he fired, and was awakened by the report. On another occasion they found him asleep on the top of a locker or bunker in the cabin, when they made him believe he had fallen overboard, and exhorted him to save himself by swimming. He immediately imitated all the motions of swimming. They then told him that a shark was pursuing him, and entreated him to dive for his fife. He instantly did so, with such force as to throw himself entirely from the locker upon the cabin-floor, by which he was much bruised, and awakened of course. After the landing of the army at Louisburgh, his friends found him one day asleep in his tent, and evidently much annoyed by the cannonading. They then made him believe that he was engaged, when he expressed great fear, and showed an evident disposition to run away. Against this they remonstrated ; but, at the same time, increased his fears, by imitating the groans of the wounded and the dying; and when he asked, as he often did, who was down, they named his particular friends. At last they told him that the man next himself in the line had fallen, when he instantly sprung from his bed, rushed out of the tent, and was roused from his danger and his dream together, by falling over the tent-ropes. After these experiments, he had no distinct recollection of his dreams, but only a confused feeling of oppression and fatigue ; and used to tell his friends that he was sure they had been playing some trick upon him. This is another point of conformity with somnambulism ; one of whose most distinctive peculiarities it is, that neither the trains of thought nor any of the events of the somnambulistic state are remembered in the ordinary waking condition, though the impression of the feelings strongly excited during that state, is sometimes continued. Both the trains of thought and the events of the somnambulistic state, however, are frequently remembered with the utmost vividness on the recurrence of that state, even at a very distant interval : and of\nthe interval, however long it may have been, there is no consciousness whatever. The same thing, but more rarely, occurs in dreaming ; the dreamer sometimes recollecting a previous dream, and even taking up and continuing its thread, although he could not in the least retrace it in his waking state.\nA remarkable case of spontaneous somnambulism, which occurred within our own experience, will serve to illustrate many of the most characteristic features of the condition in question. The subject of it was a young lady of highly nervous temperament ; and the affection occurred in the course of a long and trying illness, in which almost every form of hysteria, simulating tetanus, epilepsy, coma, and paralysis, had successively presented itself. Although natural somnambulism ordinarily arises out of ordinary sleep, yet in this instance the patient usually passed into the somnambulistic condition from the waking state ; the transition being immediately manifested by the peculiar expression of the countenance. In this condition her ideas were at first entirely fixed upon one subject\u2014the death of her only brother, which had occurred some years previously. To this brother she had been very strongly attached ; she had nursed him in his last illness ; and it was perhaps the return of the anniversary of his death about the time when the somnambulism first occurred, that gave to her thoughts that particular direction. She talked constantly of him, retraced all the circumstances of his illness, and was unconscious of anything that was said to her which had not direct reference to this subject. On one occasion she mistook her sister\u2019s husband for her lost brother ; imagined that he was come from heaven to visit her; and kept up a long conversation with him under this impression. This conversation was perfectly rational on her side, allowance being made for the fundamental errors of her data. Thus, she begged her supposed brother to pray with her ; and on his repeating the Lord\u2019s Prayer, she interrupted him after the sentence \u201c forgive us our trespasses,\u201d with the remark, \u201c But you need not pray thus; your sins are already forgiven.\u201d Although her eyes were open, she recognised no one in this state, not even her own sister, who, it should be mentioned, had not been at home at the time of her brother\u2019s illness.\nOn another occasion, it happened that, when she passed into this condition, her sister, who was present, was wearing a locket, containing some of their deceased brother\u2019s hair. As soon as she perceived this locket, she made a violent snatch at it, and would not be satisfied until she had got it into her own possession, when she began to talk to it in the most endearing and even extravagant terms. Her recognition of this locket, when she did not perceive that her sister was the wearer of it, was a very curious fact, w'hich may be explained in two w\u2019ays, each of them in accordance with the known laws of somnambulism. Either the concentration of her thoughts on this one subject caused her to remember only that which was","page":692},{"file":"p0693.txt","language":"en","ocr_en":"SLEEP.\t093\nimmediately connected with her brother ; and her unconsciousness of the presence of her sister might be due to the absence of the latter at the time of his death, which caused her to be less connected with him in the thoughts of the somnambulist: \u2014 or it may have happened that she was directed to this locket by the sense of smell, which is frequently exalted in a very remarkable degree in the somnambulistic state. (See Smell) Her feelings were so strongly excited by the possession of the locket, that it was judged prudent to check their continuance ; and as she was inaccessible to all entreaties on the subject, force was employed to obtain it from her. She was so determined, however, not to relinquish it, and was so angry at the gentle violence used, that it was found necessary to abandon the attempt; and she became calmer after a time, and at last passed off into ordinary sleep, which was in her ease the successor, instead of being (as it usually is) the predecessor, of the somnambulistic state. Before going to sleep, however, she placed the locket under her pillow, remarking, \u201c Now I have hid it safely, and they shall not take it from me.\u201d On awaking in the , morning,she had not the slightest consciousness of\" what had passed ; but the impression of the excited feelings remained ; for she remarked to her sister, \u2014 \u201c I cannot tell what it is that makes me feel so ; but every\ntime that S----comes near me, I have a kind\nof shuddering sensation;\u201d\u2014the individual named being a servant, whose constant attention to her had given rise to a feeling of strong attachment on the side of the invalid, but who had been the chief actor in the scene of the previous evening. This feeling wore off in the course of a day or two. A few days afterwards, the somnambulism again recurred ; and being upon her bed at the time, she immediately began to search for the locket under her pillow. In consequence of its having been removed in the interval (in order that she might not, by accidentally finding it, be led to inquire into the cause of its presence there, of which it was thought better to keep her in ignorance), she was unable to find it ; at which she expressed great disappointment, and continued feeling for it, with the remark, \u201c It must be there ; 1 put it there myself a few minutes ago ; and no one can have taken it away.\u201d In this\nstate, the presence of S------ renewed her\nprevious feelings of anger; and it was only by sending S\u2014\u2014 out of the room that she could be calmed and induced to sleep.\nThis patient was the subject of many subsequent attacks, in every one of which the\nanger against S----revived; until the current\nof thought changed, no longer running exclusively upon what related to her brother, but becoming capable of direction by suggestions of various kinds presented to her mind, either in conversation, or, more directly, through the several organs of sense. On one occasion, the attack having come on whilst she wras alone, she managed to make her way\ndown stairs, along a passage, and out into the garden by a back-door, although completely paraplegic,\u2014a very curious instance of sleep-walking. So nearly did her condition, in some of these attacks, approach the waking state, that the case might then be almost regarded as one of double consciousness,\u2014 that very curious affection, of which the subject seems to lead two distinct lives, A and B, in neither remembering what takes place in the other, but each state being, as it were, continuous with itself.\nThe preceding case is well adapted to illustrate the general characters of the somnambulistic condition : we have now to notice some of those peculiar phenomena which are presented in individual cases. The first of these to which we shall advert, is the extraordinary exaltation of the sensibility to external impressions through one or more of the organs of sense ; which would seem to result, in some instances, from the concentration of the attention upon that one class of impressions, but which, in other cases, is independent of any such state of attention.* We have ourselves been particularly struck with this, in the somnambulism induced by the \u201c hypnotic \u201d process of Mr. Braid, to which we shall presently refer. We have seen unequivocal proof that the sense of smell has been exalted to an acuteness at least equalling that of the most keen nosed ruminant or carnivorous animal; that the sense of hearing has been rendered equally acute ; and that the sense of touch has been exalted, especially in regard to temperature, to a degree that would be scarcely credible, were not the phenomena in perfect keeping with the exaltation of the other senses. We are not aware that the sense of sight has ever been thus acted on. In most somnambulists it is altogether suspended ; and those who claim to possess the power of clairvoyance, reading words inclosed in opaque boxes, &c., do not refer their power of doing so to any unusual acuteness of their visual organs, but attribute it to the development of an entirely new faculty, for the operation of which any such optical instrument as the eye is altogether unnecessary. Among the senses most commonly exalted in somnambulism, is that \u201cmuscular sense\u201d by which all our voluntary movements are guided ; and this seems to be so much increased in acuteness, as quite to replace the visual sense, in the performance of many of those operations for which sight is ordinarily requisite. Thus we find that sleep-walkers make their way over the roofs of houses,\n* The young lady whose case we have just detailed, exhibited, in a former attack of nervous disorder, a most extraordinary acuteness of the auditory sense, so that it was difficult to prevent her from hearing everything that passed in the house. Of a conversation held in an ordinary tone, in a room two stories below, she could hear every word as distinctly as if it had passed in her own chamber. Yet she did not suffer pain, as might have been expected, from the excessive loudness of ordinary sounds.\nY Y 3","page":693},{"file":"p0694.txt","language":"en","ocr_en":"SLEEP.\n694\nsteadily traverse narrow planks, and even clamber precipices; and this with far less hesitation than they would do in the waking state. The fact seems to be, that they are utterly unconscious of the danger they are incurring ; and that the whole attention being fixed without any distraction upon the indications of the muscular sense, the requisite movements are performed under its guidance with steadiness and certainty. So, again, it is well known that somnambulists will write with their usual degree of neatness and regularity, when prompted to do so either by their own train of thought, or by some suggestion from without ; and this, when it is perfectly certain that they cannot see. We have ourselves witnessed this in hypnotic experiments on two individuals, and made quite sure that vision could not be affording any assistance, by holding a large book between the eyes and hand of the writer. Not only were the lines well written, and at the proper distances, but the i\u2019s were dotted and the t's crossed ; and in one instance, the writter went back half a line to make a correction, crossing off a word, and writing another above it, with as much correctness as if he had been guided by vision. The guidance of the muscular sense in this case may be compared to that which we ourselves receive from it, when ascending or descending a pair of stairs, or traversing a passage, to which we have previously been accustomed, in the dark ; we know when we have come to the end, without having counted our steps, or in any way observed our progress, simply by the information we receive through the muscular sense. To the suspension, complete or partial, of the activity of one or more of the organs of sense, which may occur spontaneously, or may be induced by calling off the attention from it, reference has already been made.\nThe next point to be noticed is the readiness with which the train of thought may be guided, during the state of somnambulism, by the principle of suggestion. This is more, perhaps, the case in artificial or induced than in natural somnambulism ; for in the latter there is frequently, as already pointed out, some dominant idea or set of ideas, from which the attention of the somnambulist cannot easily be distracted. In the former, the mind is like a weathercock, without the least fixity or self-control, but liable to be turned in any direction by the impressions to which it is subjected. It is one of the most curious and important of Mr. Braid\u2019s discoveries, that the suggestions conveyed through the muscular sense are among the most potent of any in determining the current of thought. Let the face, body, or limbs be brought into the attitude expressive of any particular feeling, or into a condition at all corresponding with that in which they would be placed for the performance of any voluntary action, and the corresponding mental state is at once called Up. Thus, if the hand be placed upon the vertex, the somnambulist will frequently, of\nhis own accord, draw his body up to its fullest height, and throw his head slightly back ; his countenance then assumes an expression of the most lofty pride, and his whole mind is obviously possessed by the feeling. Where the first action does not of itself call forth the rest, it is sufficient to straighten the legs and spine, and to throw the head somewhat back, to arouse the feeling and the corresponding expression to its full intensity. During the most complete domination of this emotion, let the head be bent forward, and the body and limbs gently flexed; and the most profound humility then takes its place. So, again, if the angles of the mouth be gently separated from one another, as in laughter, a hilarious disposition is immediately generated ; and this may be immediately made to give place to moroseness, by drawing the eyebrows towards each other and downwards upon the nose, as in frowning. Not only have we witnessed all these effects repeatedly produced upon numerous \u201c hypnotised \u201d subjects, but we have been assured by a most intelligent friend who has paid special attention to the psychological part of this enquiry, that having subjected himself to Mr. Braid\u2019s manipulations, and been only partially thrown into the \u201c hypnotic \u201d state, he distinctly remembers everything that was done, and can retrace the uncontrollable effect upon his state of mind which was produced by this management of his muscular apparatus.\nSo, again, not merely emotional states but definite ideas are thus excitable. Thus, if the hand be raised above the head, and the fingers are flexed upon the palm, the idea of climbing, swinging, or pulling at a rope is called up ; if, on the other hand, the fingers are flexed when the arm is hanging down at the side, the idea excited is that of lifting a weight; and if the same be done when the arm is advanced forwards in the position of striking a blow, the idea of fighting is at once aroused, and the somnambulist is very apt to put it into immediate execution. On one occasion on which we witnessed this result, a violent blow was struck, which chanced to alight upon a second somnambulist within reach ; his combativeness being thereby excited, the two closed, and began to belabour one another with such energy, that they were with difficulty separated. Although their passions were at the moment so strongly excited, that even when separated they continued to utter furious denunciations against each other, yet a little discreet manipulation of their muscles soon calmed them, and put them into perfect good humour. The power of the operator, in regulating the state of mind of such somnambulists, is almost unlimited ; and surpasses the credibility of those who do not discern the very simple principle on which it is exercised. The facility with which particular feelings or ideas may thus be excited, will of course be dependent in part on the previous character and habits of the somnambulist.\nAgain, a very uncommon degree of power","page":694},{"file":"p0695.txt","language":"en","ocr_en":"695\nSLEEP.\nmay be determined to particular muscles, as Mr. Braid has shown, either by a suggestion (so to speak) applied directly to themselves, or by the induction of such a mental state as shall be most fitted to call them into energetic operation. Thus the extensor muscles of a limb may be excited to contraction by gently rubbing or pressing the surface above them ; and this contraction may not merely raise the limb, but may keep it fixed in a cataleptiform manner for a much longer time than any voluntary effort could accomplish. This contraction may be caused to give way at any moment, by gently wafting a current of air over the same surface, which seems to call oft the attention from the muscles to the skin. In order to throw an extraordinary degree of power into a group of muscles by a mental process, all that is required is to suggest the action, and to assure the somnambulist that it can be accomplished with the greatest facility if he will only determine to do it. Thus, we have seen one of Mr. Braid\u2019s hypnotised subjects, a man remarkable for the poverty of his muscular development, lift a twenty-eight pound weight upon his little finger alone, and even swing it round his head, \u2014 upon being assured that it was as light as a feather. We have every reason to believe that the personal character of this individual placed him above the suspicion of deceit ; and it is obvious that if he had practised such a feat (which very few, even of the strongest men, could accomplish without practice), the effect would have been visible in his muscular development. The same individual declared himself altogether unable to raise a handkerchief from the table, after many apparently strenuous efforts ; having been assured that its weight was too great for him to move. Of course, there was not an equal proof of the absence of deception in this second case as in the first; but if the reality of the first be admitted there need be no difficulty in the reception of the second, since both are manifestations of that mental condition which has been shown to be so characteristic of this state, \u2014 the possession of the mind by a dominant idea, which, when infused into it (as it were) by the principle of suggestion, directs the bodily movements, and is not corrected by the teachings of ordinary experience, or even by present sensations, it the mental assurance be strong enough to cause these to be disregarded.\nOf the causes of somnambulism, no very definite account can be given. In some persons this state recurs frequently, or even habitually; in others occasionally. In the case formerly detailed, its access might generally be traced to some strong mental emotion. Those in whom it presents itself spontaneously are said to be natural somnambulists; but it may be induced, not merely in them, but in others who have manifested no predisposition to it, by certain artificial procedures. In many cases this may be effected through the mind alone, the simple expectation of the result being sufficient to bring it about. Thus\nthe Abb\u00e9 Faria was accustomed to induce somnambulism by placing his patient in an arm-chair, and then, after telling him to shut his eyes and collect himself, pronouncing in a strong voice and imperative tone the word \u201c dormez,\u201d which generally produced on the individual an impression sufficiently strong to give a slight shock, and occasion warmth, transpiration, and sometimes somnambulism. \u2014 The following case is another illustration of the effect of this state of expectation, acting in concurrence with a fixed position. The subject of it was a lady who had previously shown great susceptibility to the \u201c mesmeric \u201d and \u201c hypnotic \u201d processes.\n\u201c We now requested our patient to rest quietly at the fire-place, to think of just what she liked, and look where she pleased, except at ourselves, who retreated behind her chair, saying that a new mode was about to be tried, and that her turning round would disturb the process. We very composedly took up a volume which lay on the table, and amused ourselves with it for about five minutes ; when, on raising our eyes, we could see, by the excited features of other members of a little party that were assembled, that the young lady was once more magnetised. We were informed by those who had attentively watched her during the progress of our little stratagem, that all had been, in every respect, just as before. The lady herself, before she was undeceived, expressed a distinct consciousness of having felt our unseen passes streaming down the neck.\u201d*\nPerhaps the most effectual of all modes of inducing somnambulism is that discovered by Mr. Braid, and practised extensively by him under the designation of hypnotism.-]' The following is his description of his mode of inducing it, and of the phenomena attending its production. \u201c Take any bright object (I generally use my lancet-case) between the thumb and fore and middle fingers of the left hand ; hold it from about eight to fifteen inches from the eyes, at such position above the forehead as may be necessary to produce the greatest possible strain upon the eyes and eyelids, and enable the patient to maintain a steady fixed stare at the object. The patient must be made to understand that he is to keep the eyes steadily fixed on the object, and the mind riveted on the idea of that one object. It will be observed that, owing to the consensual adjustment of the eyes, the pupils will be at first contracted ; they will shortly begin to dilate, and after they have done so to a considerable extent, and have assumed a wavy motion, if the fore and middle fingers of the right hand, extended and a little separated, are carried from the object towards the eyes, most probably the eyelids will close involuntarily, with a vibratory motion. . . . After ten or fifteen seconds have elapsed, by gently elevating the arms and legs, it will be found\n* Brit, and For. Med. Rev., vol. xix. p. 477.\nf Neurypnology, or the Rationale of Nervous Sleep, considered in relation with Animal Magnetism, &c., by James Braid, M. R. C. S. E., &c.\nY Y 4","page":695},{"file":"p0696.txt","language":"en","ocr_en":"696\nSLEEP.\nthat the patient has a disposition to retain them in the situation in which they have been placed, if he is intensely affected. If this is not the case, in a soft tone of voice desire him to retain the limbs in the extended position, and thus the pulse will speedily become greatly accelerated, and the limbs, in process of time, will become quite rigid and involuntarily fixed. It will also be found that all the organs of special sense, excepting sight, including heat and cold, and muscular motion or resistance, and certain mental faculties, are at first prodigiously exalted ; such as happens with regard to the primary effects of opium, wine, and spirits. After a certain point, however, this exaltation of function is followed by a state of depression, far greater than the torpor of natural sleep. From the state of the most profound torpor of the organs of special sense, and tonic rigidity of the muscles, they may at this stage be instantly restored to the opposite condition of extreme mobility and exalted sensibility, by directing a current of air against the organ or organs we wish to excite to action, or the muscles we wish to render limber, and which had been in the cataleptiform state. By mere repose the senses will speedily merge into the original condition again.\u201d We have ourselves frequently witnessed the induction of somnambulism after this method ; and whilst fully admitting its potency, we are bound to say that the almost invariable success which it has in the hands of Mr. Braid himself, appears partly due to the mental condition of the patient, who is usually predisposed to the \u201c hypnotic \u201d state by the expectation of its certain production, and by the assurance of a man of determined will that it ccmnot be resisted. When the hypnotic state, however, has been induced a few times in the manner just described, the subject can usually send himself to sleep very readily by looking at his own finger, brought sufficiently near the eyes to occasion a sensible convergence of their axes ; or even by simply standing still, and fixing the eyes on a distant point. In all cases, the fixation of the eyes is the circumstance of most importance; although the withdrawal of other stimuli has a decided influence in favouring the production of the effect. The peculiar condition of the muscular sense, as felt through the ophthalmic branch of the fifth pair, seems to have a closer relation with the subsequent state than has the condition of the visual sense; for the same effect may be produced at night, or in blind persons, if the eyes can be kept in a fixed position, especially in one that produces a feeling of muscular tension. And it seems to be in facilitating this, that the sense of sight comes into play in the operation just described. How far the mode in which the somnambulism is produced has an influence upon its phenomena, it may not be very easy to determine. For an account of these peculiarities, we must refer to Mr. Braid\u2019s treatise already quoted ; but we may cite the following, as having ourselves repeatedly\nwitnessed it and satisfied ourselves of its reality. \u201c The remarkable fact that the whole senses may have been in a state of profound torpor, and the body in a state of rigidity, and yet by very gentle pressure over the eye-balls the patient shall be instantly roused to the waking condition, as regards all the senses and mobility of the head and neck, in short, to all parts supplied with nerves originating above the origin of the fifth pair, and those inosculating with them, \u2014 whilst they will not be affected by simple mechanical appliance to other organs of sense, \u2014 is a striking proof that there exists some remarkable connection between the state of the eyes, and condition of the brain and spinal cord, during the hypnotic state. Another remarkable proof to the same effect is this ; Supposing the same state of torpor of all the senses, and rigidity of the body and limbs, to exist, a puff\u201c of air or a gentle pressure against one eye will restore sight to that eye, and sense and mobility to one half of the body \u2014 the same side as the eye operated on ; \u2014 but will leave the other eye insensible, and the other half of the body rigid and torpid as before.\u201d *\nWe consider that the experimental researches of Mr. Braid throw more light than has been derived from any other source upon the phenomena of Mesmerism. That there is much of reality mixed up with much imposture in these phenomena, is a conclusion at which most candid persons have arrived who have given their attention to them ; and we have little doubt that a searching investigation, carried on under the guidance of his results, would lead to something like a correct discrimination between the two. The induction of mesmeric somnambulism appears to us to be fully explicable by the facts we have previously stated, as to the influence of the mental condition of the patient,\u2014 namely, the state of expectation, and the additional confidence derived from the mental impression produced by the operator,\u2014and as to the effect of the fixation of vision. The ordinary phenomena of the mesmeric somnambulism itself are in most respects identical with those of hypnotism, except in this particular,\u2014that there seems to be a peculiar relation between the somnambulist and the mesmeriser, which does not exist between the somnambulist and any other individual, excepting one who is en rapport with the mesmeriser. This relationship may perhaps be not unreasonably regarded as the result of a dominant idea, which possessed the mind at the moment of falling asleep, and which continued to influence it so long as the somnambulism lasts. We have examined into the history of many cases, in which it was affirmed that mesmeric sleep was induced without any consciousness on the part of the subject of it that any influence was being exercised ; but we have never been able to satisfy ourselves that such was unequivocally the case. When the patient was expecting the performance) * Op. cit. p. 64. note.","page":696},{"file":"p0697.txt","language":"en","ocr_en":"SLEEP.\n697\nand was waiting m quiescence for its -commencement, the expectation alone was sufficient to induce the sleep. When the patient had no such expectation, all attempts to produce the sleep, that have come to our knowledge, have completely failed. Hence we are strongly inclined to the belief that the relation between the mesmeriser and the somnambulist is one of a purely mental character, and not the result of any new physical power. With regard to what have been termed the \u201c higher phenomena\u201d of mesmerism, we believe that without regarding them as the result of intentional deception, most of them are capable of receiving a very simple explanation on the principles already laid down,\u2014 namely, that in the state of somnambulism the senses, or some of them, are often endowed with a wonderful acuteness, which causes the mind to be acted on by impressions that might be affirmed to be too faint to be perceived ; and that these impressions will suggest trains of thought, and give rise to respondent actions, which are frequently of a kind that the will could not produce. As to the reality of the so-called clairvoyance, repeated personal examination has led us to a negative conclusion. The sources of fallacy arising from the causes we have mentioned, as also from the tendency on the part of the bystanders to afford assistance by asking \u201c suggestive\u201d or \u201c leading questions,\u201d and from their disposition to interpret the -least shadow of a resemblance into a complete coincidence, are such as greatly to diminish the wonder that a firm belief in the reality of these phenomena should be entertained by many persons of excellent judgment and great discrimination and acuteness as to all ordinary matters.\nA state in most respects corresponding with natural somnambulism is frequently induced by the inhalation of ether, chloroform, and other anaesthetic agents. Instead of being completely comatose, the patient, though quite unconscious of pain, may be awake to external impressions received through some of his organs of sense, so as during an operation to obey the directions given him in order to facilitate its performance ; and yet he shall be completely unaware of what has taken place when the effects of the anaesthetic agent have gone off But even the sense of pain may not be extinguished, and the patient may scream and struggle even more violently than in the waking state ; and yet the whole is subsequently forgotten, or is remembered only as a troubled dream. It was further to be noticed that, during the employment of ether, the state of the nervous system induced by it appeared to be much influenced by the previous degree of confidence entertained by the patient as to its results. The more potent action of the chloroform, however, has prevented this influence from being so apparent.\n( IV. B. Carpenter.)\nSMELL. \u2014 The sense through which we take cognizance of odours.\nOf the nature of odorous emanations nothing is certainly known. They are generally supposed to consist of material particles of extreme minuteness, detached from the odorous body, and dissolved or suspended in the air. This idea derives its chief support from the facts that most odorous substances are volatile, that is, their loss of weight, when exposed to the air, shows that their particles really diffuse themselves through it,\u2014that most strongly odorous substances are extremely volatile\u2014and that circumstances which increase the volatility of such substances also augment their odorous powers. These general statements, however, are not without their exceptions. Thus, in the first place, we do not find that many gaseous substances are truly odorous ; the pungent, irritating qualities, by which many of them are distinguished, not being perceived through the sense of smell but through that of touch. Again, although it is true that a great number of volatile liquids are odorous, the strength of their scent bears no constant proportion to their respective volatility ; and water, which is so constantly diffused through the air, has no odorous property. And with regard to solids, we find that although some of those which are most strongly odorous are also volatile (such as camphor), yet this is not by any means universally the case ,* for it has been proved by experiment that no diminution in weight can be ascertained to take place in musk or amber, although they have been freely exposed to the atmosphere for many years, and have imparted their perfume to an almost incalculable volume of air. These considerations have led some philosophers to suppose that odorous emanations are not material, but dynamical: \u2014 in other words, that the impressions made upon our olfactory organ do not result from the contact of diffused particles detached from the odorous body ; but that they are effected by a change propagated through the atmosphere or other medium, in the same manner as sound is produced by undulations that originate in the sonorous body, and are transmitted onwards, through some material medium, to the organ of hearing. There are strong objections, however, to this hypothesis. In the first place, we find that odours are not perceived unless the air, gas, or liquid in contact with the olfactory surface is, or has been, in direct continuity with the odorous body ; the interposition of any substance which prevents the actual passage of the odoriferous medium being sufficient to prevent the transmission of the odour. This is by no means the case in regard to sound, or to any other agent that is known to be dynamically propagated ; for we find many substances which are capable of conducting these agents, that is, of transmitting their influence through unlimited spaces ; and this may be accomplished in spite of any number of interruptions in their continuity, provided the chain of conducting substances be complete. Thus, sonorous vibrations may be transmitted from air to liquids, from liquids","page":697},{"file":"p0698.txt","language":"en","ocr_en":"SMELL.\nto solids, from air to solids, from solids to air, &c. ; and many such changes usually take place, before the vibrations originating in a sonorous body are communicated to the sentient extremities of the auditory nerve. The same is the case with heat, light, electricity, and other agents whose transmission is believed to be dynamical : that it is not the case in regard to odorous emanations must be regarded, therefore, as a powerful argument against the idea of their dynamical nature. Another argument may be derived from the well-known fact, that odorous emanations require such a time for their propagation, as corresponds rather with the diffusion of the odoriferous medium itself, than with the mere conduction of vibrations. Thus, in a house in which free communication is established throughout by passages, staircases, &c., but in which the course of air is not very direct from one part to another, any strong odour set free in one spot will be gradually diffused through the whole house, the rapidity being governed by the circumstances which favour or obstruct the movement of air. On the other hand, the transmission of sonorous undulations, which merely throw the air into vibration, is not dependent upon its movement, and is, indeed, but little influenced by it. This argument is, perhaps, yet more cogent than the former, and may be regarded as conclusive against the dynamical theory of odours.\nIt is not difficult to explain many of the apparent inconsistencies which attend the material theory. The varieties of the olfactive power among human heings are quite sufficient to prove, that a substance which is strongly odorous to one individual may not produce any impression on the smell of another, whose scent for other substances mav nevertheless be very acute. And there is strong reason to believe that there is a great diversity in this respect amongst different species of animals, some appearing entirely insensible to odours which strongly affect others. That we do not appreciate an odour, therefore, is no proof of its non-existence ; and we have no right to say of any volatile or gaseous substances, that they aie not odorous, but simply that they are not odorous to us. Again, the sense of smell, like the other senses, is rather relative than positive -, that is to say, it rather estimates a change in the condition of the surrounding medium, than its actual permanent state. This is fully proved by the fact that persons who habitually dwell amongst odours of any one kind, become, in time, entirely insensible to them, although their olfactive sense may remain of its full acuteness in regard to any different scent. This being the case, we at once perceive that water, oxygen, nitrogen, and carbonic acid could not, in accordance with the general laws of sensation, possess any odour to animals whose organs of smell are constantly imbued with them. We shall presently find that the moisture of. the olfactory membrane is a necessary condition of its\nfunctional power ; and thus neither fishes, which have their olfactory surface constantly bathed in water, nor air-breathing animals, whose pituitary membrane is lubricated with it, could take cognisance of any odorous properties which it might really possess. In like manner, the nasal cavities of animals being continually filled with a mixture of oxygen, hydrogen, and carbonic acid, these gases cannot excite the olfactive sense ; whilst on the other hand, we can easily imagine that if animals were adapted to breathe hydrogen or its strongly odorous compounds, they would be insensible to the latter, whilst they might distinguish oxygen, nitrogen, or carbonic acid by their respective odours, just as readily as we distinguish phosphuretted, sulphuretted, or carburetted hydrogen.\nAlthough it is through the atmosphere that odorous emanations are most readily conveyed, yet there can be no reasonable doubt that they may be transmitted through water also. Thus we find fishes provided with a complex organ of smell, which seems to be of considerable importance in directing them towards their prey. This may be inferred, not merely from the fact that the olfactive ganglia and nerves are of large size relatively to the rest of the encephalon, but also from the circumstance, well known to fishermen, that many fish are particularly attracted by odorous bait. Some anglers are even in the habit of scenting their bait with essential oils, in order to render it more alluring.\nThe general structure of the organ of smell in man has already been described (Nose) ; but some particulars recently ascertained by Messrs. Todd and Bowman respecting the minute anatomy of the pituitary membrane, and the structure and distribution of the olfactory nerve, are too important to be passed by. That the true sense of smell is specially, if not exclusively, the endowment of the upper portion of the organ, has been inferred by anatomists from the limited distribution of the olfactory nerve, and by physiologists from the fact that odours are only perceived strongly when the odoriferous air is drawn into the upper part of the cavity. The lower part of the nasal cavity is properly to be regarded as the orifice of the respiratory passages : it is extremely sensitive to irritants, but it does not participate in the discrimination of odours properly so called ; and its mucous membrane is covered with a ciliated columnar epithelium. On the other hand, the limits of the olfactive region \u201c are distinctly marked by a more or less rich sienna-brown tint of the epithelium, and by a remarkable increase in the thickness of this structure compared with the ciliated region below ; so much so, that it forms an opaque soft pulp upon the surface of the membrane, very different from the delicate, very transparent film of the sinuses and lower spongy bones. The epithelium, indeed, here quite alters its character, being no longer ciliated, but composed of an aggregation of superposed nucleated particles, of pretty Uniform appear-","page":698},{"file":"p0699.txt","language":"en","ocr_en":"SMELL.\n699\nance throughout ; except that, in many instances, a layer of those lying deepest, or almost deepest, is of a darker colour than the rest, from the brown pigment contained in the cells. These epithelial particles, then, are not ciliated ; and they form a thick, soft, and pulpy stratum, resting on the basement membrane. The deepest layer often adheres after the others are washed away.\u201d The vessels of the olfactive membrane in the foetus present a regular series of papillary loops ; but these cannot be seen in the adult. \u201c The olfactory filaments form a considerable part of the entire thickness of the membrane, and differ widely from the ordinary cerebral nerves in structure. They contain no white substance of Schwann, are not divisible into elementary fibrill\u00e6, are nucleated and finely granular in texture, and are invested with a sheath of homogenous membrane.\u201d These nerves thus rather correspond with the gelatinous fibres, than with the ordinary tubular fibres of the trunks and branches of true nerves ; and they are regarded by the authors as direct continuations of the vesicular matter of the olfactory bulb or ganglion. \u201c Although these nucleated olfactory filaments lie in great abundance under the mucous membrane of the olfactory region, we have been quite foiled in our attempts to trace their ultimate distribution in the membrane, and the difficulty is attributable to their want of the characteristic white substance. Their elongated nuclei render the larger branches un-mistakeable ; but if these become resolved at last into fibrous elements, the nuclei cease to be distinct from those of the numerous nucleated tissues which they traverse.\u201d \u201c We are averse from speculating prematurely on the meaning of anatomical facts ; but as some hypothesis will intrude itself, we would venture to hint that the amalgamation of the elements of the peripheral part of the nervous apparatus in the larger branches, and probably in the most remote distribution, as well as the nucleated character indicative of an essential continuity of tissue with the vesicular matter of the lobe, are in accordance with the oneness of the sensation resulting from simultaneous impressions on different parts of this organ of sense, and seem to show that it would be most correct to speak of the first pair of nerves as a portion of the nervous centre put forward beyond the cranium, in order that it may there receive, as at first hand, the impressions of which the mind is to become cognisant.\u201d* It has also been remarked by the same excellent observers -f, that on the septum narium and spongy bones bounding the direct passage from the nostrils to the throat, the lining membrane is rendered thick and spongy by the presence of ample and capacious submucous plexus of both arteries and veins, of which the latter are by far the larger and\n* Physiological Anatomy and Physiology of Man, Vol. ii. pp. 5\u201411.\nf Op. cit. p. 3.\nmore tortuous. And they surmise, with much probability, that the chief use of these may be to impart warmth to the air, before it enters the proper olfactive portion of the cavity ; as well as to afford a copious supply of moisture, which may be exhaled by the abundant glandul\u00e6 seated in the membrane. \u201c The remarkable complexity of the lower turbinated bones in animals with active scent, without any ascertained distribution of the olfactory nerves upon them, has given countenance to the supposition that the fifth nerve may possess some olfactory endowment, and seems not to have been explained by those who rejected that idea. If considered as accessory to the perfection of the sense in the way above alluded to, this striking arrangement will be found consistent with the view which thus limits the power of smell to the first pair of nerves.\u201d *\nThe olfactive organ, in other air-breathing Vertebrata, corresponds with that of man in all the essential particulars of its structure ; being a cavity opening anteriorly upon the face by the external or anterior nares, and posteriorly into the upper part of the pharynx by the internal or posterior nares. It may thus be considered as the entrance of the respi-\nratory passages, which is dilated for the extension of the olfactive membrane ; or, perhaps, it would be more correct to speak of it as a diverticulum from the commencement of the respiratory tube, since, as we have seen, the proper olfactive organ does not extend into that portion of the cavity which is placed in a direct line between the anterior and posterior nares. The development of the olfactive organ, as measured by the size of the olfactory ganglia and nerves, and by the extent of the surface over which these are distributed, varies greatly in different tribes ; and details must be sought on this subject under the respective names of the classes and orders of vertebrata. The chief departure from the ordinary type is observable in the case of the Cetacea, in which the nasal cavity is almost entirely devoted to the purposes of respiration, and to the ejection of the water taken in by the mouth with the food. To animals which seek their prey in the water, an organ of smell, adapted to take cognisance of odorous emanations contained in the inspired air, would obviously be entirely useless ; and it is probable that whatever olfactive power they possess is called into exercise by the passage of the water that is spouted through the nostril. The ordinary statement that the Cetacea are entirely destitute of olfactive ganglia and nerves, and that they must therefore be entirely devoid of the sense of smell, is true only of the Delphinidee, or that division of the order which includes the dolphins and porpoises ; for the Bal\u00e6nid\u0153, or proper whales, do possess olfactive nerves, although these are comparatively of small size; and in the Manatid\u00e6, or herbivorous whales, which properly belong rather to the Pachydermata\n*\nOp. cit. p. 12.","page":699},{"file":"p0700.txt","language":"en","ocr_en":"700\nSMELL.\nthan to the Cetacea, the olfactive apparatus is formed after the usual type.\nIn Fishes, however, the plan is altogether changed, the organ of smell being no longer connected with the respiratory passages, but disposed in a cavity peculiar to itself, which opens externally by anterior nares, but has no internal communication by means of posterior orifices.\nNo distinct organ of smell has yet been discovered in the Dibranchiate Cephalopoda; but in the Nautilus, a peculiar laminated organ, strongly resembling the olfactive organ of fish, has been considered by Prof. Owen as an olfactory apparatus. The inferior Mollusca would seem to be altogether destitute of special organs of smell ; but as there is much reason to believe that some of them, especially the terrestrial Gasteropods, are guided to their food by its scent, it would not seem improbable that some part of the soft spongy glandular mantle, in which the entire body is enveloped, may be adapted to take cognizance of odorous emanations ; or that in the air-breathing species, the entrance to the respiratory sac should be endowed with a low degree of this power.\nThere is ample reason to infer, from observations of the actions of Insects, that these animals possess the olfactive power in no inconsiderable degree ; and yet no special organ for this sense has hitherto been satisfactorily made out. That many insects are guided to their food, to the proper nidus for their eggs, and to the opposite sex of their own species, and are even informed of the proximity of their natural enemies, by odorous emanations, can scarcely be doubted by any one who watches their habits, and who experiments upon their actions under a variety of circumstances. Thus, the flesh-fly will be attracted by the odour of decomposing meat, when this is completely hid from its sight ; and will deposit its eggs on the envelope with which it may be covered. On the other hand, the same insect is deceived by the odour of the Stapelia, or carrion-flower, and is led to deposit its eggs in its petals. Again, many male insects will show that they are aware of the proximity of their females, when the latter are shut up in boxes, so as to he hid from their sight, and utter no sound. And in like manner, when a predaceous insect or spider is shut up in a box that gives a sufficiently free passage to air, the small insects on which it preys will manifest their alarm at its proximity, and will endeavour to make their escape. Some entomologists have supposed the seat of the olfactory sense of insects to be in their antennae, others in the palpi, and others in the entrances to the air-tubes. No evidence can be adduced in favour of either of these suppositions that is satisfactory enough to prove it, and we have little other guide at present than \u00e0 priori probability. In regard to the last of the three suppositions, however, it may be remarked that all analogy opposes the idea that the true olfactory apparatus should be thus scattered amongst the several segments of\nthe body ; and the experiments which appear to favour it really lead to no other conclusion than this, that acrid or irritating vapours, taken in through the breathing-pores, may excite reflex movements which seem destined to expel them, or to withdraw the body from them. Such movements resemble those of coughing and sneezing in man, which are excited through the nerves of common sensation, and not through the first pair ; and they do not in the least indicate, therefore, that the sense of smell is in any way connected with the respiratory apparatus of insects, myriapods, &c. The use which many insects may be seen to make of their palpi, in taking cognizance of their food without actually touching it, suggests the idea that they are the true olfactive organs; and this idea is borne out by the fact, that these organs terminate, in the living state of many insects, in soft bulbous expansions, which shrivel up and become horny in the dead specimen, thereby obscuring their real character. On the other hand, many insects are furnished with soft membranous appendages at the base of their antennae, which seem equally adapted to perform this function. And it is asserted by Dug\u00e8s*, that insects whose antennae had been cut olf did not manifest the same cognizance of the neighbourhood of odorous substances, as did others of their kind whose antennae had been left entire. It would seem not a very improbable supposition that, as the antennae and palpi are organs of a similar class, the sense of smell may not be localised in one or other of them constantly ; but that it may be assigned to one or the other, according to the modifications they may respectively require for the performance of their other offices. The same doubt exists in regard to the olfactive organ of the Crustacea. The manner in which crabs and lobsters are attracted by odorous bait placed in closed traps, makes it almost certain that they must possess some sense of smell ; and the most probable locality of the organ would seem to be a cavity discovered by Rosenthal at the base of the first pair of antennae.\nAs to the existence or absence of the sense of smell in the lower Invertebrata, nothing can be definitely stated.\nNerve of smell. \u2014 That the first pair of cranial nerves is the true olfactive, and that through it alone are the proper odorous emanations perceived, would seem a legitimate inference from the fact, that its development in vertebrated animals is constantly proportionate, c\u0153leris paribus, to the acuteness of the sense ; and that it is chiefly distributed to that part of the nasal cavity, which is most distinguished by the possession of this endowment. This inference is fully borne out by the facts supplied by experiment and pathological observation. The division of the olfactory nerves in animals evidently produces a complete destruction of the power of perceiving odours ; although they are still affected\n* Physiologie Compar\u00e9e, tom. i. pp. ICO, IG I.","page":700},{"file":"p0701.txt","language":"en","ocr_en":"SMELL.\n701\nby irritating vapours. They do not immediately perceive these vapours, however, but seem indifferent to them at first, and then suddenly and vehemently avoid them as soon as the Schneiderian membrane becomes irritated. It was maintained by Magendie that the fifth pair in some way furnishes conditions requisite for the enjoyment of the sense of smell ; this sense being destroyed, according to his assertion, by section of its trunk. His experiments, however, were made with irritating vapours which excite sternutation ; and he inferred the loss of\u2019 the sense of smell from the absence of the automatic movements which these vapours normally excite. This inference was altogether unjustifiable ; since the experiments in question afford no proof that the power of perceiving odours, with which the excitement of automatic movements does not appear to be in any way connected, is destroyed by section of the fifth pair. A diminution in the acuteness of the true sense of smell, however, appears to be a usual result of paralysis of the fifth pair ; but this is readily accounted for by the diminution of the normal secretion of the pituitary membrane, by which its surface is deprived of the moisture that is necessary for the exercise of its sensory powers. The difference in the endowments of the first and fifth pairs of nerves, and the speciality of the former, are further marked by the result of mechanical irritation of their trunks and branches. Such irritation of the first pair excites no muscular movement, either direct or reflex, and it produces no indication of pain. On the other hand, irritation of the nasal branches of the fifth pair is obviously attended with violent pain, and excites various automatic muscular movements. Lastly, it has been found that in cases of deficiency or loss of the sense of smell, some abnormal condition of the olfactive nerves or ganglia has existed ; and the same kind of change has been discovered in cases in which subjective sensations (i. e. sensations not originating in external objects) had existed during life.\nConditions of the exercise of the sense.\u2014The first condition requisite for the exercise of the sense of smell, is the contact of the odoriferous medium with the olfactive surface. This may be favoured or prevented by a variety of circumstances. Thus, odours are more rapidly transmitted by air in motion than by air at rest ; but they only proceed in the direction of the movement: and hence animals possessed of the keenest scent, which would be alarmed by the presence of a human or other foe a mile off on the windward side, may be approached within a short distance on the leeward, when a fresh breeze is stirring. The odoriferous medium must not only be brought to the nose, but it must be introduced within the olfactive cavity. This is usually accomplished by the ordinary movement of inspiration, which draw's a current of air through the nose ; but as the current chiefly passes through the lower, part of the nasal cavity, to which the olfactive nerve is very sparingly or not at\nall distributed, the full use of the sense of smell is not thus gained. It is only by making a series of short and quick inspirations,\u2014the effect of which seems to be, to empty the whole nasal cavity of the air it previously contained, and thus to cause the newly-inspired air to pass forcibly into its upper part, instead of merely streaming through the passage between the anterior and posterior nares,\u2014that we employ our olfactive powers to the best advantage. This movement, combined with the direction of the nostrils towards the source of the odour, and with the dilatation of their orifices by the muscles adapted for that purpose, constitutes the active exercise of the sense, which may be termed scenting. This bears the same relation to ordinary smelling, as feeling bears to touch, listening to hearing, or looking to seeing. The effect of the sensory impression on the mind is further heightened by the attention which is bestowed upon it ; and it does not seem improbable that the sensation itself is rendered more acute by an increased determination of blood to the olfactive surface when it is being thus actively employed. On the other hand, the use of this sense may be prevented, not merely by the closure of the nares, anterior and posterior, so as completely to exclude the odoriferous medium, but also by simply refraining from drawing air into the nasal cavity. If we breathe through the mouth only, closing the posterior nares by means of the velum palati, we may avoid being affected by odours even of the strongest and most disagreeable kind ; for the nasal cavity being already filled with air, there is no room for the entrance of the odoriferous atmosphere from without ; and it may thus be long before the odorous particles come into contact with the olfactive surface.\nIt is, of course, an essential condition of the exercise of this sense, that the whole nervous apparatus, which forms the essential part of its organ, should be in a state of integrity ; and that a free circulation of blood shall take place through the olfactive portion of the pituitary membrane. But, in addition, it is requisite that the epithelial and mucous covering of the membrane be in a normal state. If the surface be too dry, the odorous particles cannot undergo that solution in the fluid in contact with the sentient extremities of the nerves, which seems necessary for the production of an impression on them. On the other hand, when the secretion is too abundant, it interferes with its contact in the opposite manner. And thus it happens that the sense of smeli is blunted, both in the primary and secondary stages of an ordinary cold, by the disorder of the secreting surface, independently of the effect which the disturbance of the circulation may have upon the functional power of the olfactive nerve.\nPurposes of the sense.\u2014When we take a comprehensive survey of the animal kingdom, we at once perceive that the most general, and therefore the most essential purpose of the sense of smell, is to make known the pre-","page":701},{"file":"p0702.txt","language":"en","ocr_en":"702\nSMELL.\nsence of food, to indicate its direction and thus to guide the animal towards it, and to aid in the discrimination of its qualities. We always find the olfactive organ placed in the neighbourhood of the mouth ; its connection with the respiratory apparatus is by no means so constant. In air-breathing vertebrata, whose olfactive cavity opens into the pharynx, the sense of smell largely participates in that of taste (see Taste), being the means by which we take cognisance of the flavours of sapid bodies introduced into the mouth. Of the importance of this sense in directing animals to their food, it is needless to multiply instances ; but we may remark that, from observation of the actions of the human infant, we are well convinced that it is rendered cognisant by smell of the neighbourhood of its nurse, long before it recognises her by sight, and that this sense is its guide in seeking the source of its nutriment. How purely instinctive this action is, \u2014 that is, how completely independent of all experience, and entirely dependent upon the provocative sensation,\u2014is well shown by the experiment of Galen, who placed a kid, just dropped, near three vessels, one filled with milk, another with honey, and another with wine ; after smelling at all three, it presently began to drink the milk. It would seem to be by the information conveyed through their smell, that bees are induced to fly to pastures at a great distance from their hive ; and it would not seem improbable that the sense of directum, which is so remarkably displayed by many animals, is the result of the acuteness of their olfactive power. Whilst the chief use of smell to the carnivorous tribes is to guide them to their prey, the herbivorous races, whose food is constantly within their reach, are warned by its means of the neighbourhood of their enemies. The sense of smell is subservient to defence in another way; being the means by which the foetid scents, emitted by many animals under the influence of alarm, deter their enemies from further pursuit. In nearly all animals, the sexual secretions are more or less odorous ; and these would seem to be intended, not merely to contribute to make the sexes aware of each other\u2019s proximity, through the sense of smell, but also, in many instances, to serve as a provocative to sexual desire. The odours which are attractive to animals are usually related either to their food or their sexual instinct ; but there are cases in which animals seem to delight in odours which have no such relation : thus, cats seem to revel, as it were, in the odour of Nepeta (catmint) or Valerian.\nIn the air-breathing vertebrata, the sense of smell is, as it were, the sentinel of the respiratory organs, having for its office to take cognisance of the aeriform fluids which enter them, and to give warning of such as are injurious. The contact of irritating matters, however, is perceived (as already stated) through the general sense of feeling, not the special sense of smelling ; and it is through the fifth pair that the act of sneezing is ex-\ncited, the purpose of which is to expel such particles from the nasal cavity. The distinction is well seen in some air-breathing inverte-brata, whose organ of smell is seated in the head, whilst the impression of irritants on the respiratory surface, exciting reflex movements for the purpose of avoiding or expelling them, is made through the stigmata. Thus M. Dug\u00e8s relates* that if the stigmata on one side of a decapitated Scolopendra be exposed to an irritating vapour, the body will be immediately flexed in the opposite direction ; and that if the stigmata on the opposite side be then similarly irritated, a contrary movement will occur ; whilst by exposing the anterior stigmata on one side, and the posterior on the other, to the same irritation, the body will be bent into the form of the letter S.\nIn man, the sense of smell is not ordinarily so acute as it is in many of the lower animals ; yet it is very possible that it may be capable of taking cognisance of a greater variety of odours. In the selection of his food, it is to him by no means the infallible guide that it seems to be in many other races ; for it not only gives no warning, in many instances, of what is noxious, but renders certain poisonous substances (as, for instance, those charged with prussic acid or the essential oil of almonds) positively attractive. So, again, in regard to the respiratory organs, whilst it gives warning of the presence of certain gases and emanations which are injurious, it takes no cognisance of many others which are not less hurtful. In the ordinary conditions of civilised life, man is not dependent upon his sense of smell for many of the ends which it answers in other animals ; hence this sense is altogether subordinate to others, and the want of it is not usually attended with any great inconvenience. But the case is far different among savage tribes, to whom it is as important as it is to other animals in a state of nature, and in whom it seems to acquire, by the constant habit of attention to its indications, a similar acuteness. Thus, it is stated by Humboldt that the Peruvian Indian, in the middle of the night, is informed of the proximity of another individual by his smell, and can distinguish by his sme\u2019l whether the stranger be an European, an American Indian, or a Negro. It has even been asserted that some other savage tribes of mankind are enabled to follow a track by the scent of the footsteps, like the bloodhound. The sense of smell, moreover, usually acquires great acuteness, when, from deficiency of the other senses, its indications become the chief or only means of recognising bodies not in immediate contact with the individual. Thus, in the well-known case of James Mitchell, who was deaf, blind, and dumb from his birth, it was the principal means by which he distinguished persons, and enabled him at once to perceive the entrance of a stranger. Mr. Wardrop gives the following curious account of the mode in which he exercised this sense, and of\n* Op. cit. tom. i. p. 162.","page":702},{"file":"p0703.txt","language":"en","ocr_en":"SMELL.\nthe information which he derived from it : \u2014 \u201c There were some people whom he never permitted to approach him, whilst others at once excited his interest and attention. The opinions which he formed of individuals, and the means he employed to study their character, were extremely interesting. In doing this, he appeared to be chiefly influenced by the impressions communicated to him by his sense of smell. When a stranger approached him, he eagerly began to touch some part of his body, commonly taking hold of the arm, which he held near his nose, and after two or three strong inspirations through the nostrils, he appeared to form a decided opinion regarding him. If this was favourable, he showed a disposition to become more intimate, examined more minutely his dress, and expressed by his countenance more or less satisfaction ; but if it happened to be unfavourable, he suddenly went off to a distance with expressions of carelessness or disgust. When he was first brought to my house to have his eyes examined, he both touched and smelled several parts of my body; and the following day, whenever he found me near him, he grasped my arm, then smelled it, and immediately recognised me, which he signified to his father by touching his eyelids with the fingers of both hands, and imitating the examination of his eyes which I had formerly made.\u201d We learn from the same account, that in selecting his food, he was always guided by his sense of smell, for he never took anything into his mouth without previously smelling it carefully. He always recognised his own clothes by their smell, and refused to wear those which belonged to others.\nSometimes the peculiar acuteness of this sense is restricted to a particular odour or class of odours, these usually proceeding from objects for which there is either a special fondness or a particular aversion. Thus, a gentleman blind from birth, who had an unaccountable antipathy to cats, so that he could never endure the presence of one in his apartment, one day, when in company, suddenly leaped up and exclaimed that a cat was in the room, begging his friends to remove it. It w'as in vain that, after careful inspection, they assured him that he was under an illusion. He persisted in his assertion, and his agitation continued ; and on the door of a small closet being opened, it was found that a cat had been accidentally shut up in it.\nWith such unequivocal proofs of the acuteness of the sense of smell which may exist in the human subject, the statements made respecting the extraordinary exaltation of the faculty in various forms of somnambulism become less incredible ; and the author is fully satisfied, from his own observations upon individuals hypnotised by Mr. Braid (see Sleep), that this exaltation may certainly take place in regard to the sense of smell. In one instance, a glove being placed in the hand of the hypnotised subject, he found out the owner of it without difficulty, from amongst more than sixty persons, scenting at each of\n703\nthem, one after ano.ther, until he came to the right individual. And in another case, the owner of a ring was in like manner unhesitatingly found out from amongst a company of twelve.\nThe information conveyed by the sense of smell is restricted to the quality and intensity of the odour, and to some general notion of its direction. This last, indeed, is rather derived from a comparison of its relative intensity when the face is turned towards different sides, than from any more direct information as to locality furnished by the organ itself. The absence of any consciousness of the part of the olfactory surface specially affected by the impression,\u2014so that, unless the experiment be made, we know not that we are constantly exerting the sense on both sides, the double sensation being perceived as a single one, \u2014 is attributed by Messrs. Todd and Bowman *, with much probability, to the peculiar plexiform arrangement of the fibres of the olfactive nerve, and to the want of the isolation usually effected between the fibres by the white substance of Schwann.\nVarious classifications of odours, founded upon the impressions which they make upon the sense of smell, have been proposed ; but they are all liable to the objection, that there seems to be more of individual diversity in regard to the character of olfactory impressions, than with respect to those of any other kind. Many odours, by some persons thought intolerable, are very agreeable to others ; thus, assafcetida is known amongst some by the name of \u201c devil\u2019s dung,\u201d whilst by others it is spoken of as \u201cfood for the gods.\u201d It was commonly employed by the ancients as a condiment ; but the individuals who thus relish it in our own country certainly constitute the exceptions to the mass. So, again, the fumet of game, so highly valued by the epicure, is disagreeable to most persons who have not been trained to appreciate it. On the other hand, the aroma of certain flowers, which is peculiarly agreeable to most persons, is by no means so, or perhaps the reverse, to others. Thus, Muller remarks that the smell of mignonette is to him only herb-like; whilst the flower of Iris Persica has been pronounced to be of pleasant odour by forty-one out of fifty-four persons, by four to have little scent, by eight to be without all odour, and by one to be ill-scented.f\nIt more frequently happens, in regard to odours and savours, than with respect to other sensory impressions, that habit renders that agreeable, and even strongly relished, \u25a0which was at first highly repugnant.\n( W. B. Carpenter.)\nSOFTENING and INDURATION (Ramollissement et Induration, \u2014 Endurcissement, Fr., die Erweichung und H\u00e4rtung, Germ.) are terms used to express a pathological or physiological diminution and increase, of the consistence of the body or its parts.\n* Op. cit., p. 12.\nt Arnold\u2019s Physiology, vol ii. p. 561.","page":703},{"file":"p0704.txt","language":"en","ocr_en":"SOFTENING AND INDURATION.\n704\nSoftening and induration in a physiological sense, refer to those changes which occur in the density of tissues and organs during their development, growth, and decay ; whilst, in a pathological sense, they refer to alterations in the normal consistence, with or without actual molecular change.\nIn order to be able to distinguish morbid alterations of cohesion, from those which occur in the natural course of things, it is necessary to be well acquainted with the power exercised by age, sex, and idiosyncrasy, in modifying the density of the tissues.\nSoftening and induration are but relative terms, the standard of consistence is constantly varying, both as regards the whole body, or as regards organs and tissues. In the foetal state all the tissues are soft, and contain large quantities of fluid ; as development proceeds, so do the parts gradually become hard, not all equally so, for certain tissues remain permanently soft in comparison to others, which rapidly increase in density. After birth, the hardening processes still continue, and it is not until the age of puberty is passed, that all the tissues have attained their highest stage of development. But the process of natural hardening is interfered with, or retarded, by peculiar idiosyncrasy and by the influence of sex and occupation ; the general firmness of the tissue of an athlete is greater than that of those, who, although in perfect health, happen to lead inactive and sedentary lives ; it is greater as a general rule in the male than in the female sex, and in the sanguineous than in the lymphatic temperament.\nAs old age comes on, changes in the consistence of the tissues occur, which are produced by the natural decay to which all organized matter is subject ; thus the cellular tissue, the serous and mucous membranes, the muscles and tendons, bone, the brain and nervous system, and particularly the uterus and ovaries, sometimes acquire a degree of hardness, equal to that which is known to be produced by certain diseases.\nFinally, after death the whale organism is affected by forces, which had little or no influence upon it during life ; the tissues are subjected to the macerating influence of their fluids, which may also act chemically upon them. In the natural course of things, softening and putrefaction, and disorganization of the ultimate atoms of our body occur, before they are fitted to be assimilated into other organized structures ; this decay increases as time progresses, and is enhanced by a high state of temperature and exposure to the air. After death, hypostatic congestion of the cellular tissue simulates the appearance that this structure frequently presents, when affected with inflammatory softening ; and the macerating effects of the fluids, which had no such influence during life, are seen in the brain and spinal cord ; whilst the alimentary mucous membrane suffers softening and disintegration from the peculiarities of the fluid usually secreted by it. By recognising then\nthe normal alterations of cohesion, and those arising from post mortem causes, the attributes of morbid softenings will become perfectly apparent.\nSoftening and induration are said to exist without any structural change ; such is not generally the case, indeed it is exceptional, and were such a state only to be properly termed softening and induration, many of the most important and interesting pathological facts would be unaccounted for. Softening and induration are produced by a variety of causes, and frequently co-exist in the same organ, or one may supervene on, or cause, the other.\nBoth softening and induration may be produced by inflammation leading, on the one hand, to effusion of serum and pus, and on the other to the deposition and subsequent contraction and hardening of coagulable lymph ; the one appears to be the result of acute, and the other of subacute, inflammatory action. Active sanguineous congestion produces in some organs the sensation of diminished consistence, whilst in others* especially in those surrounded by a dense fibrous tissue as the testicle, hardening results. In softening, the effused product of inflammation, appears not only to break down the structure by infiltration, but also by its pressure to impede the usual nutrition of the part.\nThe softening of an organ, induced by inflammatory action, is frequently confined to one of the component tissues, especially to the cellular tissue ; the readiness with which the serous envelope may be stripped from oft' a parenchymatous organ, depends more upon the subserous cellular tissue, than upon the other structures ; and, in like manner, the softness of a whole organ is often assignable, rather to the deficient tenacity of the membrane which unites its lobules, than of the proper tissue.\nSoftening may be produced by causes totally differing from those produced by inflammation ; it may depend upon a deficiency or perverted state of the blood, and an anaemic state of the general system. For instance, in white softening of the brain, the arteries, which ought to have sufficiently nourished the affected parts, fail to do so on account of their being blocked up, more or less, by abnormal deposits. In certain softened states of the spleen, the blood contained in- its parenchyma loses its consistence, and becomes more fluid than natural, from a perverted state of its constitution ; and the flabby muscles and general loss of tone of anaemic subjects are notorious.\nIn scrofula, the perverted state of the general nutrition produces softening of peculiar tissues, for instance, of the bones ; and in the cancerous cachexia like effects occur.\nLong continued functional inactivity, for instance of the muscles of an extremity stricken with paralysis, tends to produce softening ; and pressure, in certain instances so interferes with the nutrition of a part as to diminish its cohesion. Fatty deposit in the ultimate cells","page":704},{"file":"p0705.txt","language":"en","ocr_en":"705\nSOFTENING AND INDURATION.\nof tissues and organs, renders them soft and flabby; as will also infiltrations of certain morbid adventitious products. The compound granule cells found in acute softening of the brain, and mixed with pus in other situations, are described in the article on Adventitious Products. Softening may be accompanied by atrophy, or by hypertrophy, which is generally produced bv simple congestion ; or no alteration of bulk may occur. Three degrees of softening are recognised : \u2014 in the first, the softened tissue is still solid, but it breaks down and tears and can be perforated with ease ; in the second, all solidity is gone, nothing but a pultaceous semi-fluid mass is found ; and, in the third degree, the tissue is broken down and diffluent.\nSoftened parts may retain their natural colour, or may be paler, or may have an increase of colour. Softening, without any change of tint, occurs in mucous and serous membranes, in the brain, heart, liver, and uterus. All post mortem softenings are of this kind, except where the colouring matter of the blood has tinted the effused fluids.\nIn certain softenings of the brain the affected parts are much paler than usual, being of a dead white colour ; there is a diminution in the quantity of blood usually present in the diseased parts ; a like decrease of colour is found in other softenings.\nGenerally, however, softening is accompanied by reddening, or by an increased colour ; the tints may vary from a bright vermilion to a brownish red, and may be seen as grey, almost black, and, occasionally, are yellow. These varieties of colour depend upon the amount of blood usually existing in the softened tissue, and upon the degree of congestion. The redness of softened tissues is occasionally partial, and merges into lighter tints as the tissue becomes harder. Partial effusions of blood, or highly injected vessels, are commonly found in red softenings.\nInduration, generally speaking, is to be regarded as a symptom of previous or coexisting diseased states ; its physical condition varies much in its nature, in the same or in different tissues, as proved by microscopical, mechanical, and chemical analysis ; and both observation and experiment tend to prove, that it is produced by causes of a very opposite kind.\nChanges in the amount of fluid destined for the nutrition of a part, frequently give rise to induration ; an increased quantity of blood and a consequent increased deposit of solid structure, produce simple induration of many organs, which are liable to variations in the quantity of blood they may contain, for instance, the brain and spinal marrow, the cellular and muscular tissues ; also of denser structures, as bone, in -which the induration is occasionally extreme, and in fibrous tissues ; they produce also hardening of the lymphatic glands and of the salivary glands. The brain has been found to be increased to twice its natural density and consistence. Muscular, fibrous, and cellular tissues, become so hard,\nVOL. IV.\nas to give out a grating sound when cut ; and the walls of some hollow organs, naturally soft and flaccid, acquire such a degree of firmness, that they preserve, when empty, a globular or cylindrical form, and spring up with considerable force after sudden pressure ; and parts of bone acquire that degree of hardness, which has been termed eburneoid induration. An increased quantity of the usual fluids of nutrition frequently gives rise to induration, differing from that just described, in not being attended by deposition of solids. The accumulation of blood in the vessels of the lungs and spleen, the result of congestion, produces, sometimes, a great degree of hardness and density of these organs. Diminution of the quantity of the same fluid, especially when there is also a compressing force, is also followed by an increase of consistence, and, generally, by a decrease in bulk of certain organs ; in pleurisy, for instance, dense false membranes, by their pressure, compress the lung into a small space, and its tissue becomes indurated from simple approximation ; for, on the removal of the compressing agents, the lung can be inflated.\nThe inordinate increase and accumulation of the secretion of certain organs, as the mamma, testis, gall bladder, and kidney, produce a degree of hardness, sometimes equal to that of dense tumors, arising from the incompressibility of the fluids themselves, and the state of condensation of the walls of the organs in which they are accumulated.\nEffusions of serum and blood into the tissues from mechanical causes produce great distension and induration; such is the case in the oedema of the cellular tissue of the extremities in dropsy ; effusion of serum into the intermuscular cellular tissue produces hardening. Pulmonary apoplexy and ecchy-mosis in various organs, from a mechanical impediment to the return of blood to the heart, have a like effect.\nBut inflammation of a sub-acute form is the great cause of induration, from the effusion of serum and coagulable lymph ; the former of which is absorbed, and the latter becomes \u201c induration matter,\u201d whose properties are described under the head of Adventitious Products ; this last product produces induration on account of its being actually denser than the tissues into which it is effused, and, also, by its compressing power, for it has the peculiarity of contracting and. becoming hard after its deposition. Certain morbid states of the blood, occasionally produce indurations of certain organs.\nThe changes of form, with which induration may be connected, are numerous ; none may, however, occur ; the bulk also of indurated structures varies ; it may remain unchanged, but, generally, it is increased, and more rarely, decreased.\nThe colour of indurated parts, is generally different from the normal tint ; sometimes, owing to diminished vascularity, and to the presence of induration matter, it may be pale ; at others, owing to increased vascularity, and\nz z","page":705},{"file":"p0706.txt","language":"en","ocr_en":"706\nSOFTENING AND INDURATION.\nthe state of the fluids of the tissue, and the presence of effused or infiltrated matters, it may be bright or dark red, grey, yellow, and sometimes almost black.\nInduration presents several degrees of resistance to pressure or to the knife ; much depends on the ordinary cohesion of the affected organ. Generally speaking, the first degree is characterised by a slight increase in the resistance to pressure ; the second finds the tissue denser, cutting with a cracking noise ; and the third comprehends increased cohesion, amounting to a cartilaginous or bony hardness.\nSoftening of the brain may be ascribed to inflammatory action, or to a defective state of the circulating apparatus of the organ ; it may be an effect of a defective or perverted state of the body generally, and it is frequently caused by post mortem agencies. Now these four varieties of softening, although, as regards their external appearances they have much in common, differ considerably from each other, each having peculiar attributes. The first and second varieties are generally found in the most, and the third in the least, vascular parts of the brain. Post mortem softening occurs, for the most part, in the immediate neighbourhood of the ventricles, is usually very diffused, is found on both sides at once, and is, of course, never preceded by symptoms.\nSoftening of the brain may be partial or general, and may present various degrees : the least change of consistence is only to be recognised by the microscope ; in a more advanced degree the softening is obvious to the unassisted senses, at first to the touch and then to the eye, the diseased part being pul-taceous, and readily removed by a stream of water, a cavity surrounded by healthy structure being made evident.\nIn a more advanced degree still, the cerebral substance instead of being pultaceous is quite diffluent, and occasionally a perfect solution of continuity is found. The softened portion of brain presents various alterations of colour. In inflammatory softening, the colour mainly depends upon the previous quantity of blood in the part ; it may be of a deep red colour, with or without effused clots of blood, and frequently merges at the edges into at first a deep, and then a pale, yellow colour. Sometimes the yellow colour is central and the reddened portion external, resembling a collection of pus, so much so that Lallemand described it as such.\nA dull red ochre colour with more or less hardening in the neighbouring structure, is indicative of chronic disease of long standing; as is also a chalky milk appearance, and a bright vermilion, of a recent effusion of blood into a previously softened part. In commencing softening, a diffused blush, with or without spots of blood, is generally found. A deep grey colour and fawn and dirty white tints accompany inflammatory softening, but much more frequently that which is produced by a deficient supply of blood.\nNo alteration of colour takes place in postmortem softening.\nThese distinctions of colour indicate no essential differences, as far as structure is concerned, for all coloured softenings may present the same histological characters. As a general rule, the red varieties are indicative of acute inflammation, yellow of subacute, and white or grey of deficient nutrition of the affected part ; but this rule is by no means invariable.\nUniversal softening of the brain, accompanied by a smell of sulphuretted hydrogen, is found in children suffering from general debility, and occasionally in infants stricken with induration of the subcutaneous cellular tissue.\nSoftening from a defective state of the circulatory apparatus is found, for the most part, in persons advanced in life, and constitutes what is termed white softening. It depends on the presence of osseous, cartilaginous, or atheromatous matter in the walls of the arteries, nearly or quite blocking up their entire caliber, and affecting vessels of all sizes. It may supervene upon occlusion of the common carotid from ligature, and, indeed, upon any circumstance retarding or diminishing the quantity of blood to the brain ; intense inflammation may disorganise the vessels, carrying blood to a remote portion of the brain, and thus cause softening ; or a severe blow, or the presence of a tumor of greater or less density and magnitude, may act in the same manner.\nThe very fact of adventitious products being found within the arteries, hints at a perverted state of the brain and system generally ; absorption does not progress in the diseased portions of the brain, which, having lost their supply of blood, are in a state analogous to that of an extremity attacked with gangrena senilis.\nThe softening of the brain which is produced by post mortem agencies is of very frequent occurrence. It may exist alone, or may complicate the other varieties, and is caused by the decomposition natural to organised bodies after death, or by the infiltrating action of fluids, which, either during life or in the agony of death, were effused into the ventricular cavities, and sub-arachnoid spaces.\nSoftening of the spinal cord is of not uncommon occurrence. It presents the same characters as those pertaining to the like affection of the brain, is produced by the same causes, and offers the same pathological characters. Softening of the whole cord may occur, but most frequently parts of it only are affected ; it is found softened most frequently in the lumbar region, and not unfre-quently in the cervical.\nInduration of the brain may be general or partial, and presents three degrees of consistence. In its first degree, the affected part is nearly of the consistence of a brain which has been left some time in dilute nitric acid ; in the second degree, the indurated part is of a cheesy, and in the third of a waxy, fibro-","page":706},{"file":"p0707.txt","language":"en","ocr_en":"707\nSOFTENING AND INDURATION.\nCartilaginous hardness. General induration affects either the whole or the greater part of the brain : the degree of hardness never exceeds the first variety. The induration is not always equal throughout the whole of the parts affected, the central medullary parts usually exhibiting a higher degree of it than the grey substance. A section of the indurated portions generally presents increased vascularity, in the usual speckled and striated form ; yet the reverse is occasionally observed, the brain being preternaturally white.\nInduration of the spinal cord may be general or partial. Billard found a spinal cord in a child of a few days\u2019 old, which, without the membranes, supported a pound weight. In partial induration, the white, and not the grey, matter is usually affected. For further remarks on the softening and induration of the spinal cord, see the article Nervous Centres (Abnormal Anatomy).\nSoflening of the heart occurs as a diminished state of the cohesion of the muscular structure. It is a rare disease, and is produced by very opposite causes ; from inflammation, from a defective state of the nutrition of the organ, with or without general anaemia, and from a perverted state of the nutrition of the muscular and cellular elements. The heart when softened collapses on itself when empty, tears with the greatest facility, and breaks down with little pressure, the finger perforating its substance and penetrating into its cavities with great ease. Its colour varies, being sometimes deep red and violet, at others dirty white, and occasionally of a faint yellow hue. Softening of the heart may be general or partial, superficial or deep-seated ; it may be confined to the walls of a particular cavity, or to the ventricular septum, or it may occur in small patches, disseminated in the midst of the muscular substance. Softening of the heart may coincide with hypertrophy of its walls, or a dilated state of its cavities, and Hope found it in a case of angina pectoris.\nWhen found as a sequel of carditis, the softening is of a dark tint, the fibres are dark from the whole heart being gorged with venous blood, soft and loose in their texture, being easily separable, and compressed with facility between the fingers. When accompanying chronic carditis and co-existing pericarditis, the white colour predominates, sometimes being nearly superficial, and attended by pericardial and sub-pericardial effusion.\nThe yellow-coloured softening is found in cases of local and general anaemia, in malignant fevers ; and it sometimes has an inflammatory, as well as merely cachectic origin. An abnormal deposition of adipose tissue in the cellular structure of the heart, produces softening by affecting the nutrition of the muscular fibres, which suffer also from the state of system peculiarised by the above deposition.\nInduration of the heart is said to follow carditis, and appears to be produced by the effusion of lymph into the cellular tissue, around the muscular fibres and beneath the serous membranes ; by its contraction and sub-\nsequent hardening, it may pass into a substance almost equal to bone in hardness.\nIt may exist in any part of the organ, the whole of the apex and the column\u00e6 carne\u00e6 of the left ventricle were found indurated in one case, and in another the walls of the ventricles were tough, did not collapse, and emitted on being struck, a ringing hollow sound. We sometimes find partial softenings and indurations in the same heart.\nSoftening of the lungs generally depends upon the presence of effused products of inflammation ; for instance, in the engorged, he-patised, and suppurative stages of acute pneumonia. It is worthy of remark, that, although in the hepatised stage the lungs are heavier, contain less air, and appear denser, still they are more fragile, and on being pressed by the finger break down. The more acute and recent the inflammation, the greater the softening. When we press a healthy lung with the finger, it gives to the touch on account of the elastic state of the tissue ; but this is lost, and an unusual resistance, easily broken through, is produced by the loss of air, and the presence of lymph, compound granule cells, serum, and an abnormal quantity of blood.\nIn the third stage of pneumonia, softening is produced by the alterations in the effused products; lymph, for instance, is converted into a yellow friable matter, which subsequently becomes pus. In typhoid pneumonia the softening is great, even in the first or congestive stage.\nSoftening of the lung may be produced by an insufficient supply of blood. A part of a lobe may be so indurated, that the vessels and bronchial tubes passing through it become blocked up ; the tissue which ought to have been supplied by these becomes at first soft, and finally gangrenous.\nInduration may occur in any part of the lung, it may affect simply the bronchi and the tissue in their immediate neighbourhood, or the interlobular cellular tissue and the parenchyma may suffer.\nThe bronchi after long continued and repeated attacks of inflammation are found in a more or less indurated state, the hardening being generally in the outer cellular coat, and the cartilages of the larger tubes may become as hard as bone. The lung in the vicinity is generally denser than it should be.\nThe interlobular cellular tissue may be hardened at the same time as the lobules, or separately ; it becomes more apparent than usual, and acquires a density occasionally resembling fibro-cartilage, and sometimes exercises so compressing an influence on the lobules, as to obliterate them.\nBut it is as a sequel of inflammatory action of long duration, that hardening of the whole or part of a lobe is found ; the vesicular structure first suffers, the air vesicles are obliterated, and, often enough, the bronchi and bloodvessels of a certain magnitude.\nSuch portions of lung are dense, not at all friable, possess a peculiar crispness, and contain little or no air.\nz z 2","page":707},{"file":"p0708.txt","language":"en","ocr_en":"708\tSOFTENING AND INDURATION.\nThe colour of an indurated lung may be light or dark grey, or brown, and rarely pale.\nA section of a piece of indurated lung shows the circular apertures of the bronchi and larger blood-vessels, surrounded by a dense tissue in which no vesicular structure is seen. The fibrinous dense lymph which produces these changes frequently becomes the nidus for tubercular deposit.\nPartial indurations are found around tuber* cular cavities and abscesses, and around collections of miliary, or oflarger tubercular masses.\nIn certain obstructive diseases of the heart the circulation in the lungs is so impeded, that effusion of blood, constituting pulmonary apoplexy, or effusion of lymph, producing general increase of density of the whole lung, may occur.\nLong continued pressure by a pleuritic effusion, has the effect of rendering the lung nearly solid and impervious to air.\nIn treating of alterations in the cohesion of mucous, serous, and articular membranes, it is necessary to premise that they consist of a basement membrane sustaining epithelium cells and supported by sub-basement areolar tissue in which vessels, nerves, and absorbents, are found.\nThe nutrition of the basement membrane and the proper development of the epithelium cells depend upon the amount and health of the fluid parts of the blood supplied to them by the capillaries of the sub-basement tissue. It is evident that any morbid state of this tissue will influence the integrity of the basement membrane and the epithelium cells ; and it is known that, for the most part, physical alterations of these last depend upon such morbid states, and that these changes are most likely to happen where the cellular structure is loose and considerable in amount.\nSoftening has been found in all serous and fibro-serous membranes, and may be produced by inflammatory action and by a defective and perverted state of the general nutrition of the body.\nThe lining membrane of the heart is frequently softened, being at the same time redder and more vascular than usual. It is occasionally so soft as to peel very readily from the muscular structure ; a like state of the pericardium exists with effusion of pus into its cavity. Softening of the internal membrane of the venous system is found of either a deep red or pale colour ; the tissue is very lacerable and breaks down into a pulp under the scalpel ; it may be caused by phlebitis, by the pressure of a considerable column of blood, especially when the valves have been obliterated ; and is found in cases of malignant fever, scurvy, and whenever the fluids are greatly altered. Post mortem softening is frequent enough to raise our suspicions, and great allowance must be made for the macerating and colouring properties of the blood.\nChronic softening of the internal membrane of arteries is occasionally found ; when so affected the serous tissue is easily lacerable,\nand such solutions of continuity are determined by causes, which ought in health to have no influence. Portions of the interior lining membrane may be found retracted and rolled up within the canal, so that with the effusion of lymph which generally occurs at the same time, and the consequent coagulation of a small portion of blood, the artery may become completely obstructed and obliterated in a part of its course. Occasionally, the arteries of the upper and lower extremities become thus affected in succession, on the employment of the slightest exertion, indicating a very extensive affection of the nutrition of the arterial system. We find, in cases of anaemia, and where atheroma is being deposited, considerable diminution of the general tenacity of the large vessels.\nSoftening of the arachnoid, peritoneum, and pleura is generally found where there is effusion of pus, or blood into the sub-basement tissue ; it rarely occurs when lymph is thrown out into the serous cavity, but seems to be a more advanced phenomenon of inflammation, or, rather, is produced by inflammation of a more intense and destructive character.\nDalmas ascribes nearly all serous softenings to diseased states of the subserous cellular tissue, and we find constantly that on account of the altered state of this cellular structure, the peritoneum and pleura may be stripped off large spaces of the parts they cover ; it is notorious, that in the pelvis sero-sanguineous effusion into the subserous cellular tissue, and consequent lacerability of the serous membrane, frequently occur. Pulpy degeneration of synovial membrane is a kind of softening with a perverted state of the nutrition of the tissue.\nSoftening of mucous membranes is generally produced by inflammatory causes : it is most frequently noticed, and is best studied, in the alimentary canal, part or the whole of which may be affected ; it is most frequently observed at the end of the ilium, in the depending portion of the colon, and in the c\u00e6cum ; in the right and left hypochondriac regions, and in the sigmoid flexure.\nSoftening of the mucous membrane in general, or of any one or more of its elements in particular, presents various degrees. In the first degree, the mucous membrane, instead of possessing that degree of cohesion which permits of its being detached from the submucous tissue, breaks as soon as it is seized between the fingers or blades of the forceps ; in the second degree, the edge of a scalpel, or the finger, pressed lightly over its surface, converts it into a soft and somewhat opaque creamy looking pulp ; and, in the third stage, it is so soft that it is removed with ease by a slight stream of water. In this stage portions of the mucous membrane are found partially or entirely destroyed, and having been removed by the fluid contents of the stomach or intestines, as the case may be, during life, the submucous cellular tissue is thus found destitute","page":708},{"file":"p0709.txt","language":"en","ocr_en":"SOFTENING AND INDURATION.\t709\nof its natural covering. It is in this manner that various forms of softening are produced, as irregular or circular patches of various sizes. It is important to notice this circumstance, for, when the softening is limited to thegland-ul\u00e6 solitari\u00e6, as is frequently the case in dysentery, it might be overlooked ; these bodies being very small, and their entire destruction by softening being often unaccompanied by any obvious alteration of the mucous membrane itself, the seat and nature of the intestinal affection might not be ascertained, were it not for the presence of a number of minute circular patches, which, when narrowly examined, are found to be the result of softening of these follicles ; for it often happens that enlarged follicles are seen intermixed with the patches, and which, when a scalpel is carried over the surface of the mucous membrane, break down or are removed, and thus other patches are formed similar to the former. These circular patches, which have the submucous tissue for their base, are often described as ulceration of the mucous membrane; but in all cases of doubt, the scalpel, used as above, will enable us to determine their nature.\nSoftening of the mucous membrane in the form of stripes and bands, has been described with great care by Louis, and has been much insisted upon as a characteristic of inflammatory softening ; but Carswell has proved its origin from post mortem causes.\nSoftening of the mucous membrane of the digestive organs, may present various degrees of redness, or it may be quite pale ,* the redness may be confined to the softened part, or it may extend to the neighbouring parts at the same time ; or the latter may be red and the former pale.\nThe redness of the softened membrane may vary from a light or a dark red to a brownish or purple; varieties of colour the value of which it is by no means easy to estimate, inasmuch as the quantity of blood in an inflamed tissue cannot be taken as a measure of the degree of inflammation which had caused the accumulation of this fluid.\nThe pale softening presents also some variety of tint. The softened tissue is either of a pale greyish or yellowish grey tint, being little altered from its natural colour ; or it may be paler than natural, when it generally presents a milky aspect, owing to the colour of the submucous tissue being seen through it.\nThe pale softening is found in pthisis, in tubercular disease of the mesenteric glands, and in any disease accompanied by great emaciation.\nSoftening may be accompanied by thickening of the submucous tissues, and may precede and surround ulcerations.\nThe inflammatory softening of the other mucous membranes resembles as closely as possible that which has been described ; it is not however so frequently complicated with post mortem effects, nor does it so often occur, except in the oesophagus, stomach, and intestines from the action of irritant poisons, which\nproduce it either by their direct action, or by inducing and modifying inflammation.\nSoftening of mucous membranes from post mortem causes, is of great importance as a pathological fact, and may be produced by the action of the secretions of the membrane itself, or by putrefaction. This last cause is of doubtful efficacy ; it is not likely to be met with in post mortem examinations, made at a reasonable period after death ; it may however suffice to cause complete decomposition, when the membrane has been the seat of disease before death, and more particularly when the lesion has been of such a kind as to deprive the tissue of its vital properties suddenly. General putrefaction rapidly occurs in many cases of sudden death, especially in those in which the nervous system, or blood, or both, happen to be the vehicles of the destructive agent.\nSoftening from the action of special secretions may occur in two manners, either by simple maceration, which is long in taking place, or by chemical action. The first may happen in all mucous membranes, the second in the stomaeh and intestines alone.\nUnder favourable circumstances, and at a greater or less period after death, we find softening of the coats of the stomach, perforation, and the contents of the viscus free in the cavity of the peritoneum.\nVarious opinions have been given by the most celebrated pathologists, to account for this phenomenon ; some embracing the views of Hunter, and recognising a chemical and post-mortem cause ; and others attributing it to certain inflammatory causes, which produced ulceration and subsequent perforation.\nNow, Hunter\u2019s view is demonstrable by direct experiment, whilst that held by the others is disproved by the absence of symptoms during life sufficient to account for such vast organic changes, and by the difference between such ulceration and those solutions of continuity which we are now about to describe.\nThe following facts tend to strengthen the first, and militate strongly against the latter opinion. When a rabbit, dog, cat, or any animal, in fact, is killed an hour or so after a meal when digestion is going on, and is allowed to remain in one position and in a moderate temperature, we find, after a few hours have elapsed, that the mucous membrane of the most depending part of the stomach is softened, and can, with the submucous cellular tissue and the muscular coat, be broken down with the greatest facility. The vessels ramifying in the softened part are black from the action of the solvent upon their blood.\nAfter a greater lapse of time we find the peritoneum perforated, and the contents of the stomach in its cavity ; by and by the tissues in the immediate neighbourhood of the stomach begin to suffer, and we see the abdominal muscles, and the cuticle covering them, eaten through by the gastric juice.\nIn fish, softening and perforation occur so z z 3","page":709},{"file":"p0710.txt","language":"en","ocr_en":"SOFTENING AND INDURATION.\n710\nrapidly, that, unless perfectly fresh specimens be used, no microscopic structure can be distinguished in the stomachal mucous membrane. I have noticed the same thing to occur in caterpillars : their stomachs, which contain both globular and columnar cells, after a time become softened and are perforated, so, subsequently, is the external cuticle ; nature seems to have taken this original method of doing away with useless organisms.\nIn ulceration of the stomach the affected part is generally circular, and if it reaches the peritoneum excites inflammation in the reflexion contiguous to it ; by this means perforation is rarely accomplished. Now, in post mortem perforations the softened part, said by some to be the seat of ulceration, is diffuse and the perforation large and irregular, and no part of the neighbouring peritoneum presents the slightest trace of recent inflammation ; shreds of muscular tissue and cellular membrane, moreover, form an irregular fringe around the opening, and, by their presence, detract greatly from the theory which calls such phenomena pathological and not pseudo-morbid.\nGenerally speaking, the fundus is most frequently the part of the stomach most affected by the gastric juice ; but every thing depends upon its being the most depending part, and upon its containing more or less semi-digested food.\nThe solvent matter is secreted by the tubes of the stomach, and consists of pepsin in combination with lactic acid and water : it possesses the power of disintegrating all dead structures, but cannot influence the living tissues. It is not secreted when the stomach is empty, a stimulus to the mucous coat, in the form of some matter foreign to the stomach, is necessary for its production ; it is probably the case, that an ulcer of the mucous membrane may act as a stimulus, and that a certain quantity of juice may always be present \u2022in the stomach ; and that when, by the depressing effect of this lesion, the general nutrition suffers and the tissues are less able to resist decomposition, the gastric juice may act locally on the surface of the ulcer, and produce perforation before any peritoneal adhesion is formed. Perforation of the coats of the stomach sometimes occurs suddenly after a meal ; it is produced generally by the giving way of some small ulcer, the progress of which had been enhanced by the presence of a large quantity of corroding liquid.\nPost mortem softening may modify and exaggerate softening from other causes, and differs in its own appearances under various circumstances. The colour which the softened membrane presents appears to depend upon the quantity of blood contained in the organ at the time of death ; if the quantity be small and natural, the softened parts are of a dull yellow or orange tint; and this colour increases with the quantity of the blood, and is accompanied by a black colour of the vessels. In infants and young children, and in anaemic\npatients and persons whose blood is deficient in quantity and altered in quality, containing a great disproportion of serum, the whole stornach appears as if macerated ; it is, indeed, sometimes infiltrated with serosity, and is so completely deprived of blood that no trace of this fluid is perceived except in some of the larger veins.\nPost mortem softening and perforation of the intestines may occur from the presence of an acid fluid, either within them or without, and derived from the stomach ; in the one case, softening is from within outwards, and, in the other, from without inwards.\nSoftening of the skin : the skin may be softened wholly, or one or more of its layers only. In some skin diseases, especially among scrofulous subjects, there is an alteration of the cohesion of the epidermis, which is properly formed by layers of cells, the row nearest the basement being smallest and more liquid than the others, the more distant being dry and united laterally, so as to form a dense integument. Certain defects in the quantity and quality of the fluid contained in the newest made cells prevent them from progressing, normally, in their development ; they do not become dry, neither is any disposition evinced by the basement to secrete other cells ; under these circumstances the epidermis is soft, and the basement tender and red, the tissue beneath being visible.\nThe cutis may lose its consistence in several manners. When considerable quantities of serum are collected in the subcuticular cellular tissue, the cutis becomes mechanically distended and remarkably soft ; and sometimes is only represented by a thin friable tissue, which breaks down with the least pressure. It may gradually lose its fibrous structure and degenerate into a tissue analogous to that usually found beneath it.\nSoftening also occurs as a sequel of acute active local congestion.\nThe appendages of the skin, the nails, hairs, and, in the lower animals, horns, undergo softening to a certain extent in diseases of long standing, attended with great emaciation ; and softening of the cornea with ulceration is a common symptom of starvation.\nInduration of mucous membranes, is generally caused by long continued sub-acute inflammatory action ; the sub-basement cellular tissue is generally affected, and thickening of the whole structure, with hypertrophy of the papillae, where they exist, is found at the same time. Induration with hypertrophy is consequent upon chronic dysentery, and upon chronic inflammation of the bladder. Ulceration of mucous membrane is generally accompanied by surrounding thickening and induration, and this last is frequent in the gall-bladder, gall-ducts, uterus, and urethra. Induration of mucous membranes is generally accompanied by contraction of their caliber or surface, \u2014 from the consolidation and subsequent contraction of lymph effused into the cellular structure. Fatal stricture of the intestines is produced in this manner, and so","page":710},{"file":"p0711.txt","language":"en","ocr_en":"SOFTENING AND INDURATION.\t711\nare urethral strictures. Ulceration of the stomach when healed, is followed by contraction of the cicatrix ; and when the ulcer has extended into the duodenum from the stomach, pyloric constriction of the severest kind occurs. The colour of indurated mucous membrane is generally paler than natural: the opposite may occur, and the degree of density varies from a slight increase to a bony hardness.\nAn indurated and thickened state of the membranes of the brain, pericardium, and pleura, are found after long continued chronic inflammation, either of the membranes themselves, or of the parenchymatous structures in their vicinity. Effusion of lymph behind serous membranes always tends to their becoming harder and thicker than natural ; after a while the lymph becomes organised and contracts, and produces a puckering and irregularity of the membranes. We find thickening and induration of the pleura over large tuberculous cavities, the peritoneum covering the liver, and intestinal canal, and in the sacs of old herni\u00e6. Constriction of any part of the intestinal canal, and also of the pylorus, may be produced by sub-peritoneal effusion of lymph.\nSoftening of the liver usually occurs in a manner not to be appreciated by the eye, being simply easily broken down under the finger ; occasionally, however, the liver looks as if it had been macerated for a great length of time in a dark fluid, its texture has completely lost its cohesion, and has become in certain spots quite diffluent. Livers in a state of softening may retain their ordinary colour, or it may be increased, and even decreased, in an extraordinary manner ; for, sometimes, no traces of blood can be found, except in the larger venous trunks, and the tissue of the liver is pale and light drab in colour. Softening of the liver is found frequently on the anterior and convex surface, as a product of inflammation ; partial and curable softening has been noticed to accompany inflammation of the right lung; and, finally, the consistence of the liver is much influenced by the abnormal deposition of fat, which sometimes occurs in the ultimate cells of the organ.\nInduration of the liver is generally produced by the deposition of lymph, its subsequent contraction and its compressing influence upon the lobules. This effusion is the consequence of adhesive inflammation in the areolar tissue about the twigs of the portal vein, serum and coagulable lymph are poured out, the first is absorbed, and the latter consolidated, and ultimately converted into dense fibrous tissue, which divides the lobular structure of the liver into well defined masses, gives great density and toughness to the organ, by compressing the small twigs of the portal vein, and the small bile ducts, thus impeding the flow of blood and the escape of bile, and causing the usual yellow tint which accompanies this disease.\nThis deposition of fibrous tissue produces different effects according to the parts it principally involves. Sometimes the lymph is ef-\nfused exclusively into the cellular tissue of the portal canals of considerable size, and if the person die some time after this has occurred, all the considerable branches of the portal vein are found surrounded, in some places, to the distance of half an inch, by new fibrous tissue, which by its contraction has drawn in and puckered the adjacent portions of the liver. The remaining portions of the liver may be little or not at all altered in texture, and may be readily scraped away from these indurated portions ; the main branches of the portal vein are still pervious, but many of the small branches leading from them are obliterated, the parts which they supply atrophied, and the liver correspondingly diminished in bulk. When such portions are near the surface, the capsule is drawn in, thickened and puckered, and generally covered with false membranes.\nIn other cases, the fibrous tissue is not found around the larger veins, but in the vicinity of the small twigs that separate the lobules ; all the substance of the liver is thus rendered tough ; and when the organ is sliced, the fibrous tissue is seen to form distinct lines, between small irregular masses of lobules. At the parts on the surface of the liver which correspond to these lines, the capsule is drawn in, so that the organ presents what is termed a hobnailed appearance. The degree of hardness is determined by the amount of the adventitious tissue, and, as a general rule, the denser the organ, the paler its colour ; ordinarily, the colour is pale grey, or resembles that of impure wax; and hence the term Cirrhosis.\nInduration of the liver occurs around growths, abscesses, and hydatid cysts, and may be produced by inflammatory action of a specific or non-specific nature.\nSoftening of the spleen is produced by an altered state of the fluid which it contains naturally, and by inflammatory action, or by both causes. Softening produced by the first means is common in low fever, intermittents, and scurvy ; the fibrous element of the spleen does not suffer ; but the blood, which is contained within its meshes, loses its natural consistence, appears to lose its coagulating power, becomes dark, and is washed away, leaving the white fibres intact, by a slight stream of water. In softening from inflammatory action the whole tissue of the spleen is disorganized ; it breaks down under the slight# est. pressure ; the external fibrous envelope is much softer than usual ; and its internal prolongation is totally destroyed. Both of these kinds of softening occur, with or without alteration, in the bulk and dimensions of the organ.\nInduration of the spleen may also arise from an abnormal state of the blood, and from inflammatory action. When the consistence of the blood is altered, the spleen, which may or may not be enlarged, cuts like liver or frozen muscle ; and no great quantity of blood follows the incision, the whole tissue being, in fact, denser than usual.\nInflammatory hardening may or may not be\nZ Z 4","page":711},{"file":"p0712.txt","language":"en","ocr_en":"712\nSOFTENING AND INDURATION.\nequal in degree throughout the whole organ ; frequently, certain spots, the seat of old effusions of blood, are denser than the indurated tissue around them ; and eccymoses and dark yellow and black spots, are found sometimes scattered over the hardened tissue. This variety of induration may be accompanied by increase or decrease of bulk, or no alteration in size may occur ; in degree, it may vary from the slightest increase of consistence, depending upon excessive nutrition, to a bony hardness.\nSoftening of the kidney is of common occurrence, being frequently found, with an enlarged state of the organ, in several of the diseases comprehended under the term Bright\u2019s disease. It exists also in the kidneys of diabetic subjects, and in some cases of renal calculi. When produced by inflammatory action, the softened kidney is dark red, and when a consequence of a perverted state of the nutrition of the organ, it is usually of a pale colour. Generally speaking, the softened state is produced by enlargement of the uriniferous tubes, and a consequent diminution of the solid matrix, or this last only may be affected ; and when such is the case, the tissue breaks down with the slightest pressure. In degree, softening may vary from simple flabbiness to a state approaching diffluence.\nInduration of the kidney is generally found with an atrophied state of the organ ; it is a sequel of acute, and is found in chronic, nephritis, especially in gouty subjects. In these the kidney is frequently indurated, paler than natural, less vascular, and many of its tubes may be blocked up wdth urate of soda. Induration is sometimes accompanied by an hypertrophied and a darkened state of the organ. In the first stage of induration, the consistence of the organ is slightly exaggerated, and the finger makes no impression on it ; in such kidneys we find superficial star-like venous twigs, and more or less confusion of the cortical tissue. In a more advanced stage, the tissue may become nearly as hard as cartilage, and perfectly colourless. Portions only of the kidney may be affected, but, generally, the greater part of it suffers ; and it is, comparatively speaking, rare to find cartilaginous induration of one or more of the mammilated processes.\nInduration and softening of the uterus are \u2022frequently products of acute inflammation of the organ ; the first is formed but slowly, the latter with great rapidity, and may or may not be complicated with effusion and infiltration of pus, into the muscular structure. Uncomplicated softening is frequently the result of a more chronic and subacute inflammatory action, and is occasionally found in the impregnated uterus, being made known to the practitioner by the spontaneous rupture of its walls, and the passage of its contents into the cavity of the abdomen. A softening, either general or partial, is found in cases where there were no uterine symptoms during life ; the tissue is as friable as that of a softened spleen ; but none of the pro-\nducts of inflammation are to be found. It is, probably, produced by a perverted and defective state of the general nutrition ; the uterus, from its low vitality, prominently suffering. A putrid sloughy-looking softening occurs around growths and ulcerations of the uterine tissue.\nSoftening and induration of the ovaries are usually produced by acute or chronic inflammatory action : the one, if found in the early stages of ovaritis, is produced by the effusion of serum into the tissue of the ovary ; and the other, a sequel of the same disease, is produced by the contraction and hardening of effused lymph.\nIn old age, thickening of the fibrous coat, and atrophy, and induration of the stroma, with special hardening around old Graafian vesicles, are very common : this state is frequently preceded by a flabby consistence of the organ.\nIn the puerperal stale, the ovaries are subject to complete softening and disorganization ; the natural structure is lost, and, in its place, is a pulpy diffluent bloody-looking mass.\nAn indurated state of the prostate gland is common enough in old age, and is generally accompanied by hypertrophy ; and a grey or white hardening of the testicle and epididymis, with or without destruction of the seminiferous tubes, is frequently found as a sequel of chronic inflammation.\nA softened state of the whole or part of the osseous framework of the body, is met with in scrofulous habits, and in persons suffering from cancerous cachexia, under the form of rachitis and mollities ossium. In the first of these diseases, there is a deficient deposit of earthy matter, and the animal matter is probably of an unhealthy quality ; whilst in the second, the constituents are not deficient in quantity, but bad in quality, and the vital properties of the bone are completely deranged ; the osseous structure has lost its cohesive power, and breaks with the least muscular effort. In rachitis, the bones may be bent in any direction, and are easily cut ; their centre resembling cartilage. In mollities ossium, the knife penetrates the tissue, which appears to consist of numerous cells, with thin walls, and containing an oleaginous fluid, with the greatest ease. Occasionally, bones are found so softened as to resemble lard in consistence ; and sometimes in subjects which have suffered from chronic disease, the ribs are more easily cut through than the cartilages. In caries, also, there is a softening and absorption of the bony texture, which crumbles away on the slightest touch.\nSoftening of cartilage is found under three forms. It may lose its usual elasticity and become doughy, or the usually dry and elastic cartilage of an adult may be found soft, as if it were that of an infant ; it acquires extensibility, and its elasticity diminishes. Finally, the cartilage of adult life may so lose its consistence, as to resemble embryonic cartilage ; it becomes pale and transparent, its quantity","page":712},{"file":"p0713.txt","language":"en","ocr_en":"SOLIPEDA.\n713\nof solid matter being very small, and its proportion of water great, and the softness considerable.\nFibrous tissue resembles cartilage in its alterations of cohesion, and both are apt to become indurated by a deposit of osseous matter.\nSoftening of the muscular structures may occur, as a sequel of inflammation in the cellular tissue which surrounds and binds together the ultimate fibres ; or as a result of long continued inaction, produced by loss of nervous influence, as in paralysis, or by long standing disease. Softened muscles are pale, flabby, and contain much fat ; are incapable of long or severe action, and are deficient in irritability.\nSoftening of the muscles of organic life, generally depends upon an inflammatory condition of their neighbouring submucous or subserous cellular tissue.\nSoftening of cellular tissue is very common. It has already been noticed as occurring from effusion of serum, pus, and blood. These render it more palpable and more liable to be torn, and its simple lacerability is frequently set down to softening : it is difficult, however, to draw the line. A great consequence of softening of the cellular tissue, is softening of the subjacent and neighbouring tissues; we have noticed this to a considerable extent in softening of the sub-pleural tissue, and also of the submucous and subperitoneal tissue of the alimentary canal.\nThere is hardly any part of the body in which cellular tissue is not to be found ; and consequently nearly all the tissues may be influenced by its softened state. The effusion of fluids into the areolae of the cellular tissue, may follow inflammatory action or may be produced from a malignant or typhoid state of system, and from post mortem causes.\nThe colour of the softened membrane depends upon the nature of the effused fluid.\nInduration of cellular tissue is generally caused by the effusion, and subsequent contraction and hardening of coagulable lymph ; or the simple effusion may produce hardening, as in the immediate vicinity of old ulcers. However, it is notorious that even in this case contraction and consolidation occur at a little distance from the seat of irritation ; in certain skin diseases, and in the cicatrices following burns, great injury may be effected by the contracting power of the effused lymph.\nBut it is behind mucous and serous, or serofibrous membranes, that induration from inflammatory action principally occurs, and leads to effects, most noxious to the general economy ; strictures of the gullet, pylorus, intestines, and urethra, depend upon the submucous or subserous effusion and consolidation of lymph.\nA hardened state of the mammary gland depends upon the same cause. Dense, crispcutting consolidations of cellular tissue, are frequently mistaken for scirrhus, and, indeed, are frequently the seat of morbid growths.\nInduration of the cellular tissue may de-,pend upon a perverted state of the general\nnutrition ; in syphilis, for example, there is frequently subperiosteal effusion of lymph, which has a tendency to ossify. It is also very frequently brought about, and becomes cartilaginous in hardness, by long continued local irritation. We notice the indurated state of the tissue around scrofulous glands, and its condensed form around miliary tubercles. The disease, which has been termed hardening of the cellular tissue, occurs in infants. The subjects of this disease are, for the most part, feeble, sometimes imperfectly developed, and generally born before the full period. It is a disease seen, for the most part, in hospitals, and is found where filth, bad ventilation, and worse food abound ; consisting, in a wax-like hardness of the subcutaneous cellular tissue, and is produced by the effusion of a sero-albuminous fluid into its meshes. This effusion produces swelling of the affected parts, as well as hardening ; and occurs, first of all, in the inferior extremities, passes from the feet upwards, and subsequently attacks the hands, arms, and then the trunk itself.\nThe hardened limbs are dry, cold, and may or may not pit on pressure ; their colour is either unchanged, or has a dull yellow or a lived hue. Symptoms of obstructed respiration supervene before death.\nWhen a section of an affected limb is made, and the subcutaneous cellular tissue is well exposed, we find its cellular appearance much increased, from the interstices being filled with a fluid, which is either limpid, or more concrete, and of a citron colour, or tinged with blood. The quantity of this fluid determines the degree and amount of induration ; and occasionally the fatty structure beneath the skin is hardened from the compressing influence of the effusion.\nIt is very doubtful if the effused fluid becomes wholly concrete. Chevreul says, that the serum of the blood, in infants affected with hardening of the subcutaneous cellular tissue, contains a large quantity of a spontaneously coagulable matter, analogous to that which is effused into the affected tissue. Great and general venous congestion is always found in these cases, and would seem to depend on insufficient vital energy, produced by the depressing influences of damp, bad nourishment, and cold.\nFor some particulars respecting the Softening and Induration of \u201c Growths,\u201d see article on Adventitious Products.\n(P. Martin Duncan.)\nSOLIPEDA. Syn. Solidungula, Pachydermes Solipedes. \u2014 An important group of herbivorous quadrupeds, regarded by Cuvier as constituting a third family of his order Pachydermata, and defined as \u201canimaux \u00e0 sabots non ruminans,\u201d or non-ruminant, ungulate quadrupeds. They form, however, a race of animals that presents many remarkable peculiarities of structure, and, from their great importance to mankind, demand, in a work like the present, a somewhat minute","page":713},{"file":"p0714.txt","language":"en","ocr_en":"SOLIPEDA.\n714\ndescription of their anatomy and general organisation.\nThe Solipeda, zoologically considered, comprehend but the single genus Equus, at once distinguishable from all other quadrupeds by the remarkable construction of the anterior and posterior extremities, each of the four feet appearing externally to consist of but a single toe enclosed in a solid hoof of horn, although, within, there are found concealed beneath the skin the rudiments of two other digits, appended to each side of the metacarpal and metatarsal portion of the limb.\nThe genus Equus is further characterised by the following peculiar disposition of the dental apparatus : \u2014 There are six sharp and trenchant incisors both in the upper and in the lower jaw, and an equal number of grinding teeth, the crowns of which are of a square form, each having its surface intersected by deep plates of enamel, arranged in the shape of four crescentic masses, in addition to which there exists in the teeth of the upper jaw a small disc of enamel, situated upon the inner border of each tooth.\nThe males have, moreover, two small canine teeth developed in the upper jaw, and sometimes in the lower one also ; but these canine teeth, or tushes (tusks), as they are generally called, are for the most part altogether wanting in the females. A considerable interspace exists between the canine teeth and the first molar, so that that portion of the mouth of the horse which is opposite to the commissure of the lips is devoid of any dental armature, a circumstance of which man has availed himself for the purpose of introducing into the mouth of these animals that bit by the aid of which he is enabled to subjugate his steed, and thus secure to himself the services of an assistant not less conspicuous for his indomitable strength than for his matchless docility. The stomach of the Solipeds is simple in its form, and of moderate dimensions, but their intestinal canal is of very great length, and the c\u00e6cum and colon enormous in their proportionate size.\nThus characterised, the genus Equus is found to comprehend several different races of quadrupeds that are generally regarded by modern naturalists as constituting so many distinct species. These are\u2014 1st. The Horse {Equus Caballus), \u201c man\u2019s noble companion in the chase or on the battle-field, in the labours of agriculture, in the arts, or in commerce.\u201d The original country whence the horse has been disseminated through the whole world has now become a matter of uncertainty, although most probably the wide plains of eastern Europe and of Asia, where wild horses still abound, may be pointed out as their central station. That they were in common use in Egypt from the very earliest period of which we have any record, is evident from the sacred writings (vide Gen. c. xlvii. v. 17., and c. 1. v. 9.), and hence it is supposed to have been derived by the Arabs, Persians, Ethiopians, Indians, Parthians, Scythians, &c.\nAt the present day, wild horses are by no means common even in their native regions, owing to the encroachments of man upon their original haunts ; but, on the other hand, they have spread over the vast prairies of the new continent, and may now be said to be as extensively distributed as the human race itself.\nThe second species admitted by zoologists to form a distinct race is the Dzigguetai {Equus Hemionus), intermediate in size between the horse and the ass, from both of which it is distinguished by its colour, which is light bay, with a black mane and dorsal line, and it also has a black tuft of hair at the end of its tail. This animal is found in large troops among the sandy plains of Central Asia.\n3d. The ass (Equus Asi?itis)r at once recognisable by the length of its ears, by the tuft of hair at the end of its tail, and by the black cross upon its shoulders, which is the first appearance of those transverse bands which become numerous in the succeeding species. This animal seems to be indigenous to the desert regions of Central Asia, where vast troops of them still abound in a wild state.\n4th. The Zebra {Equus Zebra), a native of the southern regions of Africa, and conspicuous for its symmetry and the alternate transverse stripes of black and white with which its skin is all over marked.\n5th. The Quagga {Equus Quaccha), a native of the same regions as the Zebra, from which it principally differs in the colour of its skin and more horse-like appearance. Its hair upon the neck and shoulders is brown, marked transversely with white stripes ; its croup is of a greyish-red colour, while the tail and legs are white. The name of this animal is derived from its peculiar voice, which somewhat resembles the bark of a dog.\n6th, The- Onagga, or Dauw {Equus mon-tanus\\ is somewhat less than the ass, and inks shape resembles the quagga. Its general colour is a light bay marked with black stripes,, that are alternately broader and narrower over the head, neck, and trunk ; the hinder stripes are directed obliquely forward, while the legs and tail remain white.\nWith respect to their anatomy, it may be observed, that all the above species resemble each other as closely in their internal economy as they do in outward form, and accordingly, in the following pages, we shall confine ourselves principally to a description of the horse, as being the typical species of the group, noticing, however, incidentally, such peculiarities of structure as may be worthy of remark in the humbler congeners of their noble prototype. So near, indeed, is the relationship between the different members of the entire genus, that they will breed together without difficulty, although the progeny of such a union, the mule, is generally incapable of reproduction. Such is well known to be the case between the horse and the ass, as also with the zebra, and doubtless with the genus generally.","page":714},{"file":"p0715.txt","language":"en","ocr_en":"SOLIPEDA.\n715\nOsteology.\u2014 Skull. The head of the horse ters*, namely, by the great enlargement be-is at once recognisable by the following charac- tween the orbits {fig. 496. a a), by its slightly\nFig. 495.\na, b, c, d, e, fi, os frontis ; b, supra-orbital foramen ; \u2014 h, i, k, parietal bone ; \u2014 l, o, p, q, occipital bone ;\nI,\toccipital protuberance ; p, condyle ; o, paramastoid process ; q, basilar portion ;\u2014r, s, t, u, w, x, temporal bone ; r, zygomatic portion ; x, suture with the malar bone ; t, glenoid cavity ; u, mastoid process ; w, tympanic ring ;\u20141, 2, 3, 4, 5, 6, lacrymal bone ; 2, position of the nasal duct ; \u2014 7, 8, 10, malar bone ; \u2014\nII,\t11, 12, 13, 14, superior maxillary; 12, infra-orbital foramen;\u201415, intermaxillary;\u201416, nasal bone ; \u2014 17, 18, 19, 19, 20, inferior maxillaiy ; 18, mental foramen ; 19, 19, coronoid process ; 20, condyle.\nFig. 496.\nA, a, a, b, c, c, d, d, f f g, g, frontal bones ; A, frontal suture ;\u2014h, h, i, i, It, parietal bones ; \u2014 in, n, n,\n\u25a0occipital ; \u2014 0,0,0, p, q, r, temporal bones ; 0, o, o, zygomatic processes ; r, suture with the malar ; \u2014 s, s, t, u, u, nasal bones ;\u2014ic, x, y, z, lacrymal bone ;\u2014 1, 1, 2, 2, 3, 3, malar bones ; \u2014 4, 4, 5, 5, 6, superior maxillary bones; 5, 5, infra-orbital foramina; 6, palatal process ; \u2014 7, 8, 9, intermaxillary bones ; 8, nasal process ; 7, palatal suture ; 9, foramen in the suture ; 10, incisor teeth ;\u201416,18, 18, inferior maxilla ; 18, 18, summits of coronoid processes.\nconvex profile, by the length of the face, which is more than double that of the cranium, and by the vertical depth of the lower jaw, which is more than that of the whole cranial portion of the skull. The temporal ridges, prolonged backwards from the post orbital apophyses, extend as far as the middle of the parietal bones, and there form a short sagittal crest upon the mesial line of the skull, whence, proceeding backwards, they diverge and extend as far as the occipital ridge, which is truncated above (as is the case in the paehydermata generally), and projects over the posterior surface of the occiput. The intermaxi Hades are prolonged considerably beyond the nasal bones, which last, by their points, arch over the cavity of the nostrils to a considerable extent. The temporal arch is comparatively very short, nearly straight, and is situated entirely in the posterior third of the skull.\nAs regards the individual bones of the skull, it may be observed that the two firontals {fig. 496. a, a,fi g) remain distinct from each other after the parietals become consolidated into one piece; they are of remarkable breadth between the orbits, and posteriorly penetrate to a considerable depth between the parietal bones. The ossa parietalia {fig. 495. h, i) give off on each side of the cranium a pointed\n* Cuvier, Ossemens fossiles, t. ii. p. 108.","page":715},{"file":"p0716.txt","language":"en","ocr_en":"716\nSOLIPEDA.\nprocess, which encroaches largely upon the squamous process of the temporal bone. The zygomatic process of the temporal {fig. 496. o) has at its base a process which projects upwards and backwards. This process constitutes the entire length of the temporal arch, articulating anteriorly by suture with the post-orbital process of the os frontis (fig. 495. b, c), which is very long : the zygomatic process of the temporal even extends to beneath the orbit, the bony circle around which it contributes to form, and is thence prolonged behind the os males, so as to become articulated with the superior maxillary bone. The occipital suture is situated considerably in front of the superior occipital ridge ; nevertheless there is generally an interparietal bone of quadrangular shape, called by hippotomists the os quadratum, but which at an early age becomes consolidated with the two parietals. The interparietal is, indeed, itself frequently divided into two pieces in the new-born foal. It is always much too narrow to reach as far as the temporals.\nThe anterior sphenoid appears but very slightly in the orbit. The posterior sphenoid mounts upwards in that region almost as high as the temporal, but without coming in contact with the parietal. Inferiorly, it is prolonged in a square form considerably beyond the pterygoid region. The glenoid cavity for the articulation of the lower jaw is situated beneath the middle of the temporal arch ; it is convex inferiorly, and has a tubercle situated behind its internal extremity, behind which, and on the same level, is situated the meatus auditorius externus. The bony meatus remains distinct from the temporal even when it has become completely consolidated with the tympanic and petrous portions of that bone. The tympanum is but little prominent, and of a very irregular shape. The petrous portion appears externally at the side of the occiput (fig. 495. u), in front of the base of the para-mastoid apophysis (fig. 495.p),which is here long and pointed.\nOf the bones of the face it may be observed, that the ascending apophyses of the intermaxillary bones (fig. 495. 15) are placed very obliquely, and become connected with the ossa nasi at about one third of the length of those bones from their anterior extremity. Inferiorly, their palatine apophyses penetrate between the maxillary bones as far as the first molar teeth, leaving two incisive foramina, or rather fissures, which are about half the length of the apophyses themselves. The pointed extremities of the ossa nasi arch over the cavity of the nose nearly as far as the middle of the intermaxillary bones. Superiorly, the ossa nasi increase in breadth as far as the inner angles of the orbits, where they become joined with the lacrymals (3, 4,5,6), which descend to a considerable distance upon the cheek, and enter almost as largely into the structure of the orbital cavity. The jugal (fig. 495. 7, 8) advances upon the cheek as far forwards as the lacrymal bone, and terminates beneath the middle\nof the orbit. This bone does not extend sufficiently far backwards to enter into the composition of the zygomatic arch, properly so called. It forms upon the side of the cheek, by its union with the maxillary bone, a broad, square ridge, which is continued backward as far as the commencement of the zygomatic arch.\nThe palatine bone is deeply notched and very narrow, not extending forward beyond the penultimate molar tooth. This bone merely forms a narrow border around the meso-pterygoid fossa, blit it composes more than two thirds of the pterygoid al\u00e6. In the floor of the orbit it mounts upwards, between the maxillary bone on one side, and the two sphenoids on the other, as far as the os frontis, but it does not come in contact with the lachrymal. The external pterygoid process of the sphenoid runs along the palatine externally, and extends beyond it, but the internal pterygoid process is distinct from the sphenoid, forming a long and narrow tongue-like process, which, after having covered the lateral suture of the anterior end of the posterior sphenoid, extends obliquely over the centre of the pterygoid process of the palatine, and proceeds to form a bony hook, situated upon the side of the great palatine fissure.\nSpinal column.\u2014Thq cervical vertebr\u0153 of the horse are, as in all mammiferous quadrupeds, seven in number; their proportions are massive, and the whole series forms a chain of great strength and considerable flexibility. All the posterior vertebr\u00e6 of the neck have in the horse a square or oblong shape, and both the spinous and transverse processes are short and stunted, so as not to interfere with that freedom and extent of motion which is essential in this portion of the spine.\nThe atlas, as in man and other mammifera, presents characters peculiar to itself. The body of this bone is entirely suppressed, its place being supplied by the two articulating surfaces appropriated to the reception of the condyles of the occipital : the superior lamina are broad and flat, and the superior spinous apophysis is not developed ; whilst, instead of transverse processes, the vertebra is prolonged laterally into two broad al\u00e6, into which numerous muscles are implanted. In the horse it may be remarked that the entrance of the canals for the passage of the vertebral arteries, instead of being situated at the posterior edge of the transverse apophyses, is placed upon its upper surface, but in other respects this bone presents no. peculiarity worthy of special notice.\nAxis. \u2014 The configuration of the second cervical vertebra in most quadrupeds differs considerably from what is met with in the human subject, owing to the horizontal direction of the neck, and the unfavourable position in which the head has to be sustained. This difference is most remarkable in the arrangement of the spinous process, which, instead of being merely a prominent tubercle, as in man, is prolonged into a vertical crest that","page":716},{"file":"p0717.txt","language":"en","ocr_en":"SOLIPEDA.\t717\nFig. 497.\nSkeleton of the Horse. (After Stubbs.)\nSkull.\u20149, orbit ; 11, 12, superior maxillary bone ; 12, infra-orbital foramen; 15, intermaxillary; 16, os nasi; 17, 18, 19, lower jaw; 18, mental foramen; 19, coronoid process. Cervical region. \u2014 a, c, the atlas ; g, h, k, the vertebra dentata ; o, body ; r, transverse ; s, t, oblique, and u, spinous processes of cervical vertebrae ; z, process from the root of the transverse process of the sixth cervical vertebrae, assisting with its fellow to form the groove in which the longus colli muscle is lodged. Dorsal region.\u2014 c, oblique, and e, e, spinous processes of the two anterior dorsal vertebrae ; 5 to 18, continuation of dorsal spinous processes. Lumbar region.\u2014a, b, c, d, e, f lumbar vertebrae ; l, the sacrum ; p, superior, and r, inferior, caudal vertebrae. Sternal region.\u2014a, b, c, osseous and cartilaginous pieces of the sternum with the cartilaginous attachments of the true ribs. Shoulder.\u2014 h, i, o, the scapula ; b, g, k, the os humeri.\nsometimes advances forwards above the atlas and is prolonged posteriorly above the third, or even the fourth, cervical vertebra, thus affording an ample expansion for muscular attachments. In the Solipeds, this spinous crest (\u00c6) is but moderately developed, extending backwards so as to overlap the third vertebra to some extent ; but its anterior prolongation is wanting. The transverse apophyses are short, and perforated by the vertebral canal, while the articular processes are but moderately developed, and directed backwards to articulate with those of the succeeding vertebra.\nThe five posterior cervical vertebrae are remarkable for their strength and mobility ; their bodies are of great proportionate size, and articulated together by broad sub-globular surfaces that allow a considerable extent of motion ; the vertebral laminae are broad and massive, and the articular processes well developed and connected together by large articulating surfaces. The spinous processes are almost wanting except upon the sixth and seventh vertebrae, that belonging to the\nlatter being of considerable size and turned backwards, so as to represent the commencement of the dorsal series of spines. The bodies of the sixth and seventh vertebrae of the neck, more particularly of the former, are prolonged inferiorly into a central crest of considerable size, which projects downwards and backwards, and gives origin to the longus colli, which muscle is likewise lodged in a kind of groove formed by osseous plates derived from the transverse processes.\nThe dorsal vertebr\u00e6 in the Solipeds are invariably eighteen in number, and are distinguished by the shortness of their transverse apophyses, each of which is provided with an articulating surface, whereby it is connected with the corresponding rib as well as by similar articulations situated on each side upon the anterior and posterior extremities of their bodies to which the heads of the ribs are affixed. The spinous processes of the anterior dorsal vertebr\u00e6 are of great length, and dilated at their extremities, where they give origin to the broad elastic cervical ligament by means of which the weight of the","page":717},{"file":"p0718.txt","language":"en","ocr_en":"718\nSOLIPEDA.\nhead is in a very material degree supported ; posteriorly, the spinous processes of the dorsal region become gradually shorter, and their extremities broad and flattened, so as gradually to approximate in their shape those of the lumbar region.\nThe vertebr\u0153 of the loins are, in the Soli-peda, usually six in number : such is the case in the horse, zebra, and quagga; but in the ass there are but five lumbar vertebrae. This portion of the vertebral column is, in the class under consideration, possessed of great strength ; the bodies of the vertebrae are broad and firmly bound together ; the transverse processes of remarkable length and power ; the articulating apophyses strong and broadly connected with each other, while the spinous processes, which are of great breadth, are either quite straight or inclined forward.\nThe sacrum in all the Solipeda is composed of five vertebrae consolidated into one piece, and, with that exception, scarcely different from the vertebral pieces that immediately precede and follow it. In the horse, as in most quadrupeds, the sacrum is much narrower in proportion than in the human subject, and forming, moreover, a continuous straight line with the rest of the spinal column, allows of much more freedom of motion in this part of the skeleton than is possible in the human subject; and this is much increased by the obliquity of the junction between the sacrum and the iliac bones. The articulation, moreover, between the last lumbar vertebra and the sacrum, still further adds to the mobility of these parts ; for in the horse, the oblique processes of that vertebra are connected with the sacrum by means of articulating surfaces of very large size, so that from the combination of all these circumstances, there is a springiness given to this region of the vertebral column, the importance of which, in galloping or leaping, is at once conspicuous.\nThe caudal vertebr\u0153 in the solipeds vary in number from seventeen to twenty-one ; but of these, the upper ones only resemble true vertebrae. Even in the first caudal vertebra, the inferior oblique processes become obliterated, and as we descend, all the vertebral apophyses rapidly disappear : at the second bone of the tail, the spinal lamin\u00e6 no longer rise high enough to enclose the spinal canal ; but resemble two short processes; and at about the fifth or sixth, all vestiges of them are lost, nothing remaining but the bodies of the vertebrae of a cylindrical shape and slightly enlarged at each extremity, until we approach the last, where all regularity of form is lost.\nThorax. \u2014 The sternum of the solipeds is considerably compressed towards its anterior extremity, which is moreover prolonged to some extent beyond the insertion of the first rib, so as to give to the whole chest a cari-nated appearance, which forcibly reminds the anatomist of the thorax of a bird. Posteriorly, the carinated form disappears, and the sternum becomes broad and flattened where it receives the cartilages of the posterior true ribs. The sternum of the horse is composed of several\nosseous pieces bound together by strong ligamentous and cartilaginous connections.\nThe ribs are eighteen in number, so that the thorax is prolonged very far backwards towards the pelvis. The anterior ribs are broad and massive ; but of these, eight only are attached to the sternum : the posterior or false ribs gradually become more slender as they recede backwards to expand over the cavity of the abdomen.\nAnterior extremity.\u2014The frame-work of the shoulder in the Solipeda, as in all ungulate quadrupeds, is composed of the scapula only ; the coracoid apparatus being dubiously represented by a rudimentary apophysis, and the clavicle is totally wanting in circumstances which allow of the close approximation of the shoulder blades to the sides of the chest, and thus cause the weight of the body to be transmitted perpendicularly to the ground.\nThe shape of the scapula {fig. 498. o) is almost that of an isosceles triangle, the spinal costa, which is about half the length of the other two, having its angles rounded off. The spine of the scapula is prominently developed, and towards its upper third, projects posteriorly, so as to form a considerable recurved process (i) ; as it approaches the neck of the bone, however, the scapular spine becomes quite obliterated, spreading out upon the margin of the glenoid cavity (A), so that no acromion process exists in these quadrupeds.\nThe humerus (fig. 498. e, b,k) is short, but of great strength, and the muscular imprints strongly marked.\nThe forearm is almost exclusively formed by the radius (fig. 498. o,r), the strength of which is in accordance with the enormous weight it has to sustain, while the ulna is reduced to a mere appendage (figA98.s,t, u), which in the adult animal is completely consolidated with its posterior surface, the line of demarcation between the two being only indicated by a furrow which, towards the upper extremity of the forearm, deepens into a slight fissure* The olecranon process is, however, of large size, and, by its projection posteriorly, affords a powerful purchase to the massive extensor muscles inserted into this portion of the limb. From the above arrangement of the bones of the forearm, it is manifest that all movements of pronation and supination are here out of the question ; the limb must remain constantly fixed in a state of pronation, in which condition it is anchylosed, and thus acquires a firmness and steadiness which would be quite incompatible with more extensive movements.\nThe carpus in the Solipeda consists of seven bones arranged in two rows, \u2014 of which four are situated in the first, and three in the second.\nThe upper series consists of the representative of the os scaphoides of the human subject (fig. 498. w) ; of the os lunare (a?) ; of the cun\u00e9iforme (?/) ; and of the os pisiforme (z).\nIn the lower series, the os trapezium, which supports the thumb of the human hand, does not exist in the horse ; but the trapezoid (not","page":718},{"file":"p0719.txt","language":"en","ocr_en":"SOLIPEDA.\t719\nseen in the figure) -, the os magnum (2.) ; and the unciforme (3.) are all of them readily identified.\nFig, 49a\nOsteology of the Horse \u2014 Bones of the anterior Extremity.\nScapula.\u2014 h, its neck ; i, spine ; k, coracoid apophysis ; l, l, inferior costa ; m, m, superior costa ; n, n, base ; o, fossa subspinalis ; p, fossa supra-spinalis.\nOs humeri. \u2014 a, shaft of the bone ; b, protuberance into which the teres major is inserted; e, bicipital protuberance ; f neck of the humerus ; i, external condyle ; K, double articular suface, articulated with the radius ; k, internal condyle ; l, anterior fossa which receives the upper head of the radius, when the forearm is bent ; m, posterior sinus, for the reception of the olecranon of the ulna, when the fore-arm is extended.\nRadius. \u2014 n, its upper head ; o, protuberance for the insertion of the tendon of the biceps; r, its lower extremity.\nUlna.\u2014 s, the olecranon process ; t, its articulation \u25a0with the humerus ; u, continuation of the bone which in aged horses becomes united with the radius.\nBones of the carpus.\u2014w, Scaphoides ; x, Lunare ; y, Cun\u00e9iforme ; z, Pisiforme or Orbiculare ; 2, \u00d6s magnum ; 3, Unciforme.\nMetacarpus.\u2014 4, 5. The great metacarpal or cannon bone. 6, 7. Kudimentary external metacarpal bone. 10, 11. Sesamoid bones.\nFore-foot. 12, 13. Pronimal phalanx or great pastern bone. 14, 15. Middle phalanx or lesser pastern or coronary hone. 16. Terminal phalanx or coffin-bone. 17. Sesamoid bone.\nThe metacarpal bones are in the horse consolidated into one large piece, called by farriers the shank or cannon bone, and two smaller supplementary pieces, which seem merely appendages to the former.\nThe large cannon bone (fig. 498. 4, 5.) is formed by the union of two metacarpal bones indissolubly conjoined, \u2014 viz. of those which support the ring and middle fingers in the human hand; these conjoined, here form a massive piece, the upper end of which articulates with tire carpus, while its distal extremity sustains the first joint of the foot.\nA second or supplemental piece (/?g.498.6,7.) is simply a rudiment representing the internal metacarpal bone of the human skeleton, or that which in man supports the little finger ; superiorly this piece presents an articulating surface, which articulates with the unciform bone of the carpus, but inferiorly, there being no finger for it to support, it gradually dwindles away to a mere splint, which is applied against the ulnar aspect of the preceding bone.\nThe third bone of the metacarpus is equally rudimentary as the last, and consists of a similar styliform bone applied against the opposite side of the shank bone, and obviously representing the metacarpal bone of the fore finger.\nThe fore foot of the horse is composed of three bones, representing the first, second, and third phalanges in the fingers of the human hand ; but extraordinarily changed in their appearance. Of these, the first {fig. 498. 12, 13 ) is equivalent to the bones of the first phalanges of the ring and middle fingers in the human subject, as is indicated by a central groove, showing this piece to be composed of two lateral halves \u2014 this bone in the horse is called the \u201cgreat pastern.\u201d\nThe second piece (fig. 498.14,15.) corresponding with the second phalanx, is named, in common language the \u201c little pastern,\u201d while the third (16), the representative of the third phalanx, a bone of very large size and crescentic shape, has received from farriers the name of the \u201c coffin bone.\u201d\nIn addition to the above may be noticed two sesamoid bones (19, 11) implanted in the flexor tendon of the foot, as it passes behind the articulation between the cannon bone and the great pastern, and a third lying over the posterior part of the articulation, between the coffin bone with the coronary bone, or between the two distal phalanges.\nPosterior extremity. \u2014 The pelvis of the so-lipeds, both in its disposition and in the shape of the bones composing it, differs in many important particulars from that of man, and even of the generality of quadrupeds. The body of the ileum is elongated into a sort of","page":719},{"file":"p0720.txt","language":"en","ocr_en":"720\nSOLIPEDA.\nneck, while its crest and spine, extending themselves outwards almost at a right angle with the body, give the whole bone a shape somewhat like that of the letter T, or of a hammer, of which the body of the bone will form the handle, while the extremity of one of its branches is articulated to the side of the sacrum, and the other forms a broad expansion, the inner surface of which is turned obliquely towards the spinal column. The body of the ileum joins the ischium and pubis at a very obtuse angle, the cotyloid cavity being excavated in the usual manner in the line of junction between the three bones.\nchanters, and prominent ridges for the attachment of the muscles implanted into it : it is however so short as to be entirely concealed within the flesh and integuments of the trunk, so that what is ordinarily designated the thigh in these quadrupeds is in reality the muscular portion of the leg. Inferiorly the articulating surface that sustains the patella is no longer, as in the human subject, continuous with that of the knee-joint, but forms a distinct articulation upon which the patella (Jig.500. q) plays during the movements of the leg.\nFig+500.\nFig. 499.\n\nLigaments of the anterior extremity of the Horse.\na, a, Ligaments of the scapula ; b, capsular ligament of the shoulder-joint ; h, radial nerve ; k, capsule of elbow-joint; cl, d, d, e, e, e, ligaments of the elbow, carpus, and phalanges ; o, outer cartilage of the hoof ; p, inner cartilage of the hoof.\nThe os femoris in the Solipeda is very strong and massive, with well developed tro-\nOsteoloay of the Horse.\u2014 Bones of the posterior Extremity.\nFemur.\u2014 a, Body of the bone ; b, its neck ; c, the head incrusted with cartilage ; d, d, trochanter major, or \u201c spoke \u201d ; f, projection of the linea aspera, into which the glut\u00e6us externus is inserted; g, fossa, whence arises the gastrocnemius externus and plantaris ; h, the external condyle ; i, cartilaginous surface supporting \u2014 q, the patella.\ns, t, external and internal semilunar cartilages of the knee-joint.\nTibia.\u2014 u, its upper head; v, articular surface, entering into the composition of the knee-joint ; w, surface for the insertion of the ligamentum patellae ; x, shaft of the bone.\nFibula. \u2014 1, Its upper extremity ; 2, its lower end gradually diminished to a point.","page":720},{"file":"p0721.txt","language":"en","ocr_en":"SOLIPEDA.\n721\nTarsus.\u2014 8, 5, Astragalus or cockal bones ; 7, os Calcis; 10, os Cuboides; 11, os Naviculare ; 12, os Cun\u00e9iforme.\nMetatarsus.\u201414, Upper extremity, and 15, lower extremity of the great metatarsal or cannon bone. 16, 17, rudimentary external metatarsal bone ; 20, Sesamoid bone.\nHind-foot.\u201422. Proximal phalanx, or great pastern ; 23. Middle phalanx, or lesser pastern, or coronary bone; 24, Last phalanx or coffin bone; 25, Sesamoid bone.\nThe leg is in the Solipeda almost exclusively formed by the tibia, which is of great strength, and very massive towards its upper extremity, where the ridges for muscular attachment stand out in bold relief ; inferiorly it becomes more slender, and approaches nearer to a cylindrical shape, expanding again inferiorly to form the articulating surface for the ankle joint.\nThe fibula (fig. 500.1, 2.) is even more rudimentary in its development than the ulna in the anterior extremity, being, in fact, nothing more than a long spiculum of bone implanted among the muscles, and laid like a slender splint along the outer and posterior angle of the tibia, with which it is firmly connected by ligamentous attachments in the vicinity of the knee-joint, whence it descends separated by a small interval from the tibia as far as the middle of that bone, to which at this point it becomes closely applied, and then, gradually becoming more and more attenuated, is towards the lower third of the leg completely lost.\nThe bones of the tarsus in the horse are, 1st, the astragalus, or \u201c cockal-bone,\u201d as it is vulgarly named (fig. 500. 3, 5.), the os calcis, or \u201c heel-bone \u201d (7), the cuboid (10), the navicular (11), the middle cuneiform and the lesser cuneiform (12). The internal or great cuneiform bone is here wanting, as also are the bones of the great toe, which, when present, it is destined to support.\nThe bones of the metatarsus, like those of the metacarpus, are three in number,\u2014viz. one large central or cannon bone, and two lateral rudimentary pieces. The central piece (fig. 500. 14, 15.), which supports the entire weight of the body, is apparently composed of the conjoined metatarsal bones belonging to the second and third smaller toes ; in the human skeleton the line of demarcation between the two being indicated by a deep longitudinal groove ; by its upper extremity this bone articulates with the three lower bones of the tarsus ; while inferiorly it presents a smooth articular surface, whereby it supports the first phalanx of the foot. The external rudiment (fig. 500. 16, 17.) is an imperfect metatarsal bone, occupying the place of that which in the human subject supports the little toe : by its upper extremity it articulates with the cuboid bone of the tarsus, while inferiorly, owing to the deficiency of the corresponding toe, it forms no articulation. The internal rudiment represents the metatarsal bone of the first of the small toes in the human foot : superiorly it articulates with the lesser cuneiform bone of the tarsus (12),\nVOL. IV.\nwhence, as it descends, it gradually diminishes in size, and is lost before it reaches the foot.\nThe bones of the hind foot resemble those already described in the anterior extremity, and are distinguished by similar names, the first phalanx of the solitary toe being the great pastern, the second the little pastern or coronary bone, and the third, or that which supports the hoof, the coffin bone : there are likewise the sesamoid bones (20), behind the articulation, between the cannon bone and the first phalanx, and also between the coronary and coffin bones (25).\nMyology. \u2014 The myology of quadrupeds is, in many points of view, a subject of particular interest, more especially in those races which are far removed from man in their general habits or in the configuration of their skeleton. In the case of the Solipeds, owing to the exceedingly aberrant structure of their extremities, the disposition of their muscular system becomes a very important subject of inquiry, and it is partly from this cause, and partly from the necessity of obtaining an accurate knowledge of the anatomy ofanimals so valuable to mankind, that the myology of the horse and its congeners has been studied with great care, and delineated with extraordinary zeal and perseverance. It is for these reasons that we shall in the present article describe at some length this portion of their economy, premising that the details here given will be found more or less applicable to quadrupeds generally, except where obvious peculiarities of structure belong to the class which forms the more immediate subject of our study.\nPanniculus carnosus. \u2014 On removing the skin, the entire body is in most quadrupeds found to be invested with a muscular covering, the thickness and consequent importance of which varies, in different parts. In the human subject the traces of this fleshy pan-nicle are very feeble, being confined to certain regions,\u2014 such as the anterior part of the neck, the palms of the hands, &c. ; but in the horse it forms a much more important investment, giving mobility to the integument, and materially contributing to the support and defence of various organs. This fleshy covering is very thick in the anterior region of the neck, whence it extends downwards upon the anterior extremities, and, becoming tendinous, is extensively inserted in conjunction with the tendons of the latissimus dorsi and teres major, into the external surface of the humerus. From this point strong muscular fibres pass downwards over the muscles of the fore-arm, where they terminate in a broad fascial expansion which embraces the lower part of the fore-leg. Another strong portion of this fleshy tegument spreads over the sides and loins, where it degenerates into a tendino-membranous layer, extending downwards as far as the penis, which it likewise invests with a carneo-membranous sheath. It likewise encases the buttocks and thighs in a strong covering of fleshy and tendinous fibres, which","page":721},{"file":"p0722.txt","language":"en","ocr_en":"722\nSOLIPEDA.\nspreads downwards over the fascia lata to the hind leg.\nIn describing the other parts of the muscular system, it will be necessary to divide them into their appropriate regions, and in so doing, we shall follow the arrangement usually adopted in describing the human subject, beginning with the\nProper muscles of the spine. \u2014 The long muscles of the spine, \u2014 viz. the spinalis and semi-spinalis dorsi, longissimus dorsi and sa-cro-lumbalis\u2014present a disposition very similar to what occurs in the human subject.\nThe spinalis dorsi takes its origin from the spinous processes of the lumbar and posterior dorsal vertebrae, as well as from the broad fascia of the loins, and running forwards is inserted by distinct tendons into the spines of the anterior vertebrae of the back. Its continuation, the spinalis cervicis, is in the horse of great strength and importance: its origin commences from the second spine of the\nback, which origin is continued for about one third of the way down that spine towards its root : it arises likewise from the third dorsal spine and the ligamentum nuchae ; from these origins it runs forward to be implanted by strong and distinct tendons into the spines of the anterior cervical vertebrae.\nThe longissimus dorsi is situated immediately external to the spinalis, taking its origin from the common mass of muscle that arises beneath the lumbar fascia, as well as from the spinous processes of the loins and sacrum, whence it runs forward to be inserted by a double set of tendons into the transverse processes of the loins and back, and also into the posterior ribs near their angles. Its continuation, the transversalis colli, is likewise of considerable strength, but offers nothing worthy of remark.\nThe saci'o-lumbalis arises, in conjunction with the latissimus dorsi, from the back of the sacrum, and also by flat tendons about\nFig. 501.\nMyology of the Horse. (A fter Stubbs.')\nHead.\u2014 n, Levator anguli oris ; o, orbicularis oris ; t, anterior dilator of the nostril ; w, masseter ; k, septum narium ; 4, vena angularis. 12, Anterior cartilage of the external ear.\nNeck.\u2014 a, Coraco-hyoideus ; g, transversalis cervicis ; l, trachelo-mastoideus, or complexus minor ; m, complexus ; y, the longus colli.\nShoulder.\u2014 c, Triceps extensor cubiti ; k, tendon of the biceps flexor cubiti.\nForearm, and anterior extremity.\u2014 a,b,c, Extensor carpi radialis; k, extensor digitorum communis ; q, analogue of the extensor minimi digiti ; C, 9, ligaments ; t, vena plantaris interna ; u, nervus plantaris intemus.\nTrunk.\u2014 d, serratus minor posticus; h, serratus major posticus; l, serratus major anticus; o, external intercostals ; p, internal intercostals ; q, rectus abdominis ; x, obliquus internus.\nHinder extremity.\u2014 b, glut\u00e6us m\u00e9dius; h, rectus femoris; n, vastus externus; u, w, 21, 26, 24, extensor digitorum pedis ; 6. plantaris and gastrocnemius.","page":722},{"file":"p0723.txt","language":"en","ocr_en":"SOLIPEDA.\nhalf the breadth of the muscle from the superior edge of all the ribs, except two or three of the most anterior ; and its slips are in-se ted by as many distinct tendons into the inferior edge of all the ribs, except two or three of the hindmost, and also into the transverse process of the seventh vertebra of the neck. The continuation of this muscle, the cervicalis descendens, offers nothing remarkable.\nThe multifidus spin\u0153, in the dorsal region arises by numerous tendinous origins from the transverse processes of the vertebrae of the back, loins, and sacrum, near their posterior protuberances, each slip running forwards to be inserted into the spinous process of the vertebra in front of that from which it derives its origin, the whole forming a thick mass, which fills up the hollow situated between the spinous and transverse processes. In the neck a similar disposition exists.\nThe intertransversarii colli take their origins from the roots of the oblique processes of the cervical vertebrae, and from between these and the transverse processes : in the horse they are of great strength and importance, running forwards to be inserted into the transverse processes of the vertebra in front of that from which they arise. In addition to the above there is a set of muscles named by Stubbs the intervertebrales, which do not exist in the human subject : these arise from the ascending oblique processes of the five inferior vertebrae of the neck, and from the space betwixt the oblique processes of the uppermost vertebrae of the back : they are each of them inserted into the lateral parts of the bodies of the vertebrae above their origin.\nThe longus colli is the only muscle, exclusively appropriated to the movements of the spine, situated in front of the spinal column. This muscle, in the horse, arises from the transverse processes of the third, fourth, fifth, and sixth vertebrae of the neck, from which origins it runs upwards to be inserted by distinct tendons into the anterior part of the bodies and transverse processes of the vertebrae above them, and into the anterior surface of the atlas.\nThe quadratus lumborum offers the same disposition as in the human subject.\nThe tail in quadrupeds, from its great development, requires for its movements a special set of muscles, of which scarcely any traces exist in the human subject. This organ in the horse is susceptible of three kinds of movements. It can be straightened or elevated, bent or brought downwards, and lastly carried to either side. These movements, again, by their combinations, produce secondary effects, so that the tail becomes susceptible of very extensive motions ; and, in such quadrupeds as have this part very largely developed, it even supplies the place of a hand, so completely is it under muscular control.\nIn order to effect these different movements, three * distinct sets of muscles are employed, which are arranged upon the same plan as the\n* Cuvier, Anat. Comp. tom. i. p. 275.\n723\nlong muscles in other parts of the spinal column ; that is to say, they arise by numerous tendinous slips, and are inserted in a similar manner, the slips of origin and insertion running, of course, in opposite directions : the latter, moreover, are prolonged to a much greater extent than in the rest of the spinal column, and firmly bound down to the vertebrae by tendinous sheaths, so as to add as little as possible to the bulk of the tail.\nThe muscles which raise or straighten the tail are all situated upon its upper aspect : they are, first,\nThe sacro-coccygeus superior (lombo-sus-caudien). This muscle arises in the horse from the inferior or posterior edge of the third spinal process of the os sacrum, and from the spines, edges, and interspinal ligaments of the sacral vertebrae behind that point, as well as from those caudal vertebrae that are possessed of spinous apophyses. The fleshy mass formed from these origins gives off numerous slender tendons : the first of these is the shortest, and runs inwards to be inserted into the base of the first caudal vertebra, in which the articular apophyses are wanting. The second tendon is inserted in a similar manner into the succeeding vertebral piece; the third into the next, and so on to the end of the tail. The number of the tendons given off is, of course, determined by that of the vertebrae. Each tendon is lodged in a sort of ligamentous canal, which forms a sheath for it throughout its whole course. When these two muscles act in concert the tail is necessarily raised upwards.\nThe interspinales superiores (spinalis obliquas ; lombo-sacro-coccygien ofVicq d\u2019Azyr). These muscles are a continuation of the inter-spinous muscles of the spine ; but as the spinous processes of the tail are short, and frequently replaced by two tubercles answering to rudiments of the oblique processes, these muscles are here disposed obliquely, being more widely separated posteriorly than they are in front.\nThe muscles which depress the tail or bend it downwards all take their origin in the interior of the pelvis, and are prolonged to a greater or less extent along the inferior aspect of the tail. These form, when completely developed, four pairs, or four pairs of series, of muscles.\n1.\tThe ileo-coccygei (ileo-sous-caudien of Vicq d\u2019Azyr) arise from the internal or pelvic surface of the ossa ilei, and, forming an elongated fleshy belly in the interior of the pelvis, terminate beneath the root of the tail, which they will consequently depress with considerable force against the anus.\n2.\tThe sacro-coccygeus inferior (sacro-sous-caudien) is the antagonist of the sacro-coccygeus superior, above described, which in structure it exactly resembles. This muscle takes its origin from the inferior surface of the sacrum and of the transverse processes of those caudal vertebrae in which these processes are developed, by a fleshy belly which gradually diminishes in thickness, and termi-","page":723},{"file":"p0724.txt","language":"en","ocr_en":"724\nSOLIPEDA.\nnates by forming as many tendons as there are caudal vertebrae without transverse processes. These tendons are received into sheaths resembling those upon the upper surface of the tail, and are inserted successively into the base of each caudal vertebra, beginning about the seventh.\n3.\tThe intcrspinales inferiores {sub-caudales, inter-coccygeus of Vicq d\u2019Azyr). These are situated beneath the mesian line of the tail. They commence underneath the articulation between the first and second caudal vertebra?, and form an elongated fleshy belly, which, in some quadrupeds that have the tail largely developed, become first of all implanted into V-shaped hones derived from the fourth, fifth and sixth vertebrae of the tail : they receive, moreover, from time to time additional fleshy slips, which go on continually diminishing in size, and give off tendons to be inserted successively into the inferior aspect of the base of each caudal vertebra.\n4.\tThe pubo-coccygeus {pubo-sous-caudien). This is a thin muscle, derived from the whole extent of the upper margin of the pelvis, and having the appearance of a fleshy membrane, the fibres of which are gradually collected into one point to be inserted beneath the tail into tubercles situated upon the base of the fourth and fifth vertebrae. The action of this muscle will produce an effect similar to that of the ileo-coccygeus.\nThe muscles adapted to move the tail laterally are arranged in two sets.\n1.\tThe iscliio coccygeus externus -(ischio-caudien) arises from the posterior or internal surface of the ischium, a little below and behind the cotyloid cavity, from which origin it runs backwards to be inserted into the transverse processes of the anterior caudal vertebrae. This muscle is improperly called by Stubbs the levatorani, because in the horse a fewfibres of it are connected with the termination of the rectum.\n2.\tThe intertransversales {intertransversal of Vicq d\u2019Azyr) extend in the form of mus-eulo-aponeurotic layers over all the transverse processes that are developed in the caudal region, their tendons of insertion being most distinctly seen upon the upper surface of the tail.\nIn animals that have the muscular apparatus of the tail completely developed the muscles are found to consist of eight distinct sets,\u2014viz., two superior, two lateral, and two inferior. In the horse some of these are deficient, or exist only in a rudimentary condition. To see them in their full state of development they must be examined in animals provided with long and mobile tails, such as the prehensile-tailed monkeys, the opossums, the lion, and, more especially, in the kangaroo and beaver.\nMuscles derived from the spinal column which serve immediately for the movements of the cranium. \u2014 These have nearly the same origins as in the human subject, but are comparatively of much greater strength, owing to the inclined position of the head with respect to the ver-\ntebral column. They may be divided into such as proceed, 1st, from the atlas ; 2nd, from the axis ; and, 3rd, from the posterior cervical vertebrae and ligamentum nuch\u00e6. To the first set belong \u2014\n1. The rectus capitis posticus minor, or rather m\u00e9dius, arising, as in the human subject, from the atlas ; from this origin it runs to be inserted by a short and broad tendon into the occiput.\nThe other muscles belonging to the atlas \u2014 namely, the rectus anticus, the rectus lateralis, and the obliquus superior\u2014offer the same position as in the man.\nThe muscles derived from the axis \u2014 viz. the rectus posticus major &nd the obliquus inferior\u2014 are likewise similarly disposed in all quadrupeds. '\nThe muscles arising from the other cervical vertebrae are\nThe complexus, which, commencing from the upper oblique process of the third vertebra of the neck, continues its origin from all the oblique processes of the neck below that point, as well as from the upper oblique process of the first vertebra of the back, also by a pretty strong tendon from the transverse processes of the seeond and third dorsal vertebrae ; from these origins it runs forwards to be inserted by a strong round tendon into the occiput close to its fellow of the opposite side : in this course it is connected by numerous tendinous processes with the ligamentum nuchae. That portion of the complexus usually distinguished by the name of digastricus eolli is in the horse undistinguishable as a distinct muscle.\nThe trachelo-mastoideus, or complexus minor, arises from the oblique processes of the third, fourth, fifth, sixth, and seventh cervical and first dorsal vertebrae, and from the transverse processes of the second and third vertebrae of the back ; it runs forwards external to the last-mentioned muscles to be inserted by a strong tendon into the mastoid apophysis of the temporal bone. The above muscles are overlapped by the\nSplenius capitis {cervico-mastoideii), which, arising by strong tendinous processes from the spinous processes of the two superior dorsal and two last cervical, and also extensively from the ligamentum nuch\u00e6, runs forward to be inserted into the transverse processes of the fifth, fourth, and third cervical vertebra, and into the transverse ridge of the occipital bone. It is remarked by Cuvier that in carnivorous quadrupeds the splenius is not inserted into the transverse processes of the cervical vertebra? as it is in herbivorous animals and in the human subject, in which the latter portion is sometimes sufficiently distinct to obtain the name of splenius colli in contradistinction to the splenius capitis. It is likewise remarkable that in the camel, if the splenius exists at all, it is extremely thin and difficult to display by dissection.\nMuscles of the ribs and stei'num. \u2014 The muscles derived from and inserted into the ribs and sternum are found in all quadrupeds to","page":724},{"file":"p0725.txt","language":"en","ocr_en":"SOLIPEDA.\t725\nhave the same general arrangement as in the human subject. In the horse, their disposition is as follows, beginning with those whose office is to raise the framework of the chest and thus assist in inspiration.\nThe scaleni differ in no remarkable respect from the corresponding' muscles in the human body. The same may be said of the intercostal muscles, the levator es co stamm, the serr\u00e2t us posticus superior (dorso-costien), the ser-ratus posticus inferior (lombo-costien), and the triangularis stei'ni (sterno-costien), the two latter of which must be regarded as depressors of the ribs, and consequently acting the part of muscles of expiration.\nIn all quadrupeds possessing a greater number of ribs, and consequently a more capacious thorax than man, the attachments of the diaphragm are found to be much, further removed from the margins of the false ribs than in the human subject : nevertheless the position which it occupies, and its connections in the thoracic cavity, are similar in all mammiferous animals.\nThe walls of the abdomen, in the horse as in the generality of quadrupeds, are composed of five pairs of muscles, to which the same names are applicable as are bestowed upon them by the anthropotomist.\nThe ob/iquus externus abdominis (costo-ab-dominien) arises, by tendinous processes that indigitate with the origins of the serratus magnus, from the external surface of all the lower ribs, beginning at the fifth ; and below the last rib it derives its posterior attachment from the fascia lumborum ; from these origins, it runs backwards and downwards, terminating in a broad tendinous expansion, the terminations of which in the linea alba, os pubis, and Poupart\u2019s ligament, together with the formation of the external abdominal ring, are exactly as in the human subject.\nThe obliquus internus (ileo-abdominien) exhibits the usual arrangement, arising tendinous and fleshy from the crest of the ileum and pubic ligament, whence it mounts obliquely forwards to be inserted into the cartilages of all the lower ribs as far forwards as the ensi-form cartilage of the sternum.\nThe rectus abdominis (sterno-pubien) is much more extensively developed in the horse than in human beings. Arising from the os pubis it passes forwards enclosed in its usual sheath to be inserted into the ensiform cartilage and into the cartilaginous terminations of the third, fourth, fifth, sixth, seventh, eighth and ninth ribs, and also into the sternum between the cartilages of the third and fourth ribs. There are even fleshy fibres derived from this muscle prolonged as far forwards as the articulation between the first rib and the sternum, which, by the old anatomists, was regarded as a distinct muscle, and named \u201c musculus in summo thorace situs.\u201d\nIn many of the Carnivora the rectus abdominis is equally remarkable for its great length, and in some species it is even prolonged forwards to the very anterior extremity of the sternum. When the recti\nare thus largely developed the pyramidales do not exist.\nAnterior extremity. Muscles of the shoulder. \u2014 It may readily be supposed that in the horse and other herbivorous quadrupeds not possessed of a clavicle, and, moreover, remarkable for the extreme simplicity of the structure of their scapular apparatus, these muscles undergo important modifications in their disposition and attachments, which it will be interesting to investigate. In the human subject the muscles specially appropriated to the movements of the shoulder are eight in number,\u2014 viz. the serrat\u00f9s magnus, the pec-tora/is minor, the levator scapul\u00e6, the rhomboi-deus, the trapezius, the omo-hyoideus, the sub-clavius, and the sterno-cleido mastoideus, all of which concur in producing the various movements of which the human shoulder is susceptible. Of these, it will be observed, the six first belong exclusively to the Scapula, except the trapezius, which is inserted extensively into the clavicle ,* whilst the operation of the two last is upon the clavicle only.\nIn quadrupeds the shoulder is furnished with the same muscles as those which are met with in man, only they present differences in their proportions and attachments, which are dependent upon the structure of the skeleton, or the particular requirements of the animal ; and, moreover, they are provided with an additional muscle, of which no vestiges appear in our own bodies. In the horse, the arrangement of the muscular apparatus of the shoulder is as follows.\nThe trapezius, in all quadrupeds destitute of clavicles, or in which these bones are but imperfectly developed, presents an arrangement very different from what exists in such as have the clavicles completely formed : that part which would in the latter case have been the clavicular portion, becomes confounded with the deltoid and with the cleido-mastoid (here a very distinct muscle from the sterno-mastoid). From the combination of these three, there usually results a single muscle, which is implanted immediately into the humerus, and which, from its attachments, might be named the masto-humeralis. It is this muscle which is named by Stubbs the levafor humeri proprius, and its posterior part musculus ad levatorem accessorms ; and by the French hippotomists muscle commun de la t\u00eate de Venclosure et du bras. This clavicular portion of the trapezius is very distinct from the scapular portion, from which it is in many animals separated by the trackelo-acromial muscle, to be described further on.\nIn the horse, therefore, the Trapezius may be said to consist of that part only which is called the ascending portion in the human subject, and which is inserted into the posterior margin of the spine of the scapula. The sterno-mastoid is present, but the levator anguli scapul\u00e6, the cleido-mastoid, and the clavicular portions of the trapezius and deltoid are all replaced by the muscular expansion above described, and which, taking its origin from the mastoid process of the temporal bone\n3 a 3","page":725},{"file":"p0726.txt","language":"en","ocr_en":"726\tSOLIPEDA.\nand from the transverse processes of some of the superior cervical vertebrae, passes downwards in front of the head of the humerus and descends along the inner surface of the forearm, into which it is ultimately inserted.\nThe muscle of the shoulder which is proper to quadrupeds may be named the trachelo-acromialis (acromio-trachelien, Cuv., acromio-basilaire, Vicq d*Azyr). It arises in the horse from the transverse process of the atlas and of the four following cervical vertebrae (in the generality of quadrupeds from the three uppermost only) ; from this origin it descends towards the shoulder-joint, making its appearance externally between the two divisions of the trapezius, which it separates ; it then spreads out over the acromial portion of the scapula, and descends as far as the middle of the humerus, where it is inserted. Its action will, of course, be to draw the shoulder upwards and forwards. This muscle, which exists in all the mammalia, with the exception of the human species, would seem to be in special relation with the quadrupedal mode of progression ; and, as Cuvier observes, affords a striking example of the difficulty of establishing a good nomenclature in comparative anatomy : in some animals, it derives its origin exclusively from the cranium ; and, in others, from the upper or lower cervical vertebr\u00e6. Its mode of insertion is equally various ; in the tapir it is implanted into the aponeurosis which covers the deltoid muscle ; while, in the horse, it has its insertion into the middle portion of the humerus hy two aponeurotic tendons, which embrace the bra-chialis internus muscle.\nThe serratus major anticus (seapulo-costien), in the horse, arises from the transverse processes of the third, fourth, fifth, and sixth cervical vertebr\u00e6, and also from the external surfaces of the six superior ribs : its origins extending as far backwards as the insertion -of the tendons of the sacro-lumbalis : from this extensive origin it passes backwards around the chest to be implanted into the base of the scapula, its insertion occupying nearly half of the internal surface of that bone. This muscle, Cuvier remarks, is much more extensively developed in quadrupeds than in the human subject ; for, in all other mammalia, except in the orang-outang, it arises not only by digitations from the ribs, but also from the transverse processes of the vertebr\u00e6 of the neck, an arrangement which becomes necessary in animals that walk upon four feet, in order to prevent the scapula from being pushed too far backwards towards the spine. This muscle, in fact, forms, with its fellow on the opposite side, a kind of sling, by which the trunk is suspended. The fact that it is equally extensive in its attachments in the Monkeys, is an additional proof that the usual mode of progression in these animals is on four feet : in these animals, indeed, the serratus magnus derives origins from all the cervical vertebr\u00e6, instead of from only a part, as in other mam-mifera. In the Cetace\u00e6 that do not walk, and in the kangaroos which have their ante-\nrior limbs very small, the serratus magnus presents a corresponding feebleness of development.\nThe pectoralis minor (serratus minor anticus) is, in the horse, represented by a muscle, which, arising from the sternum and from the first, second, third, and fourth ribs near their sternal terminations, runs upwards and backwards to be inserted into the superior costa of the scapula near the base of that bone; it also contracts tendinous attachments with the aponeurotic covering of the teres minor and other scapular muscles.\nThe rhomboideus arises, in the horse, entirely from the ligamentum nuch\u00e6, and from the spines of the anterior dorsal vertebr\u00e6, whence it runs outwards to be affixed to the base of the scapula.\nIn monkeys and in the carnivorous quadrupeds the rhomboideus is continued upwards as far as the occiput, whence it derives an extensive origin ; the occipital portion, indeed, is, in the Carnivora, separated from the rest so as to form a distinct muscle, called by some writers the oecipito-scapularis, and, by Cuvier, \u201c l'hombdide de la t\u00eate.\u201d\nThe omo~hyoideus is, generally, wanting in animals whose scapula presents no coracoid process : neither can there be any subclavius in animals that do not possess a clavicle : in the horse, however, the former of these is represented by a strong muscular fasciculus.\nIn this place it may be proper to notice the muscle named by the human anatomist sterno-eleido-mastoideus ; but which, in the lower animals, is represented by two distinct muscles. One of these,\nThe sterno-mastoideus, or, as it might be named, sterno-maxillaris, arises, in the horse, from the anterior end of the sternum, and, running forwards strong and fleshy, is inserted by a flat tendon into the inferior maxilla underneath the parotid gland, sending, however, another tendon to be implanted into the root of the mastoid process.\nThe cleido-mastoideus, always a distinct muscle from the preceding, is, as we have seen above, in the horse and other non-claviculate quadrupeds, confounded with the clavicular portions of the trapezius and deltoid.\nMuscles inserted into the humerus. \u2014 The movements of the humerus in the human body are effected by two sets of muscles : one derived from the trunk, the other from the framework of the shoulder. The former are the pectoralis major and latissimus dorsi ; the latter, the supra-spinatus, the infra-spinatus, and the subscapularis proceeding from the surfaces of the scapula and the deltoid, teres minor, teres major, and coraco-brachialis, which take their origins from the processes. In the horse and in other quadrupeds, various circumstances render modifications in the arrangement of these muscles indispensable.\nThe pectoralis major (sterno-humerien), in the horse, arises, first, from the aponeurosis of the external oblique muscle of the abdomen ; secondlj', from the two lower thirds of the sternum ; and, thirdly, from the supe-","page":726},{"file":"p0727.txt","language":"en","ocr_en":"SOLIPEDA.\t727\nrior part of the sternum for about one-third of its length. The first of these portions winds round to be inserted into the internal aspect of the head of the humerus ; the second ends in a fascia, which descends downwards over the fore-arm, while the third, running in a transverse direction over the inferior portion, is inserted into the humerus along with the \u201c levator humeri proprius \u201d between the biceps and the brachi\u00e6us internus.\nIn all those mammalia which are destitute of complete clavicles, even in the Cetacea, there is a part of the sternal portion of the pectoralis major, which is inserted perpendicularly into the humerus, that joins the corresponding portion of the opposite side to form the muscle common to both arms? by the action of which the two fore-legs are made to cross each other.\nThe latissimus dorsi (lovibo-humerien\\ in the horse, and in other quadrupeds, exhibits the same arrangement as in the human subject : it is, however, in the lower animals powerfully assisted in its action by the massy muscle already described (cutano-humerieri\u00ff, formed by the panniculus carnosus, a strong tendon from which is inserted into the humerus along with that of the latissimus dorsi. Both are intimately connected with the tendon of the teres major, and. from this combination of tendons arises one of the heads, of the triceps extensor cubiti.\nThe supra-spinatus, the infraspinatus, the subs capillar is, the teres major, and the teres minor have, in all quadrupeds, the same arrangement as in the human subject, the only differences being dependent upon the shape and proportions of the scapula.\nThe deltoid in all animals having their clavicles imperfect or wanting, is necessarily modified in its disposition to a very considerable degree. We have already seen when speaking of the trapezius, that its clavicular portion is in such cases blended with the anterior division of that muscle: that part only which takes its origin from the scapula remains to be noticed. Where the acromion is well developed, the deltoid may be divided into two portions ; one derived from the acromion, the other proceeding from the spine and subjacent surface of the scapula: these two portions unite, and,decussating each other, form a common tendon, which is implanted into the deltoid ridge of the humerus. As the acromion process diminishes in size, the acromial portion of the deltoid becomes enfeebled in like degree, until at length, as in the horse, where there is no acromial projection, that part of the deltoid arising from the spine remains alone. Under these circumstances, this muscle is directed forwards in nearly the same direction as the infra-spinatus, and, both from its position and office has been named by hippotomists the \u201c abductor longus brachii.\u201d\nThe coraco-brachialis exists even in animals that have no coracoid process, in which case it takes its origin from a little tubercle situated upon the superior costa of the scapula. When the biceps arises by two heads, as in\nthe human subject, the coraco-brachialis arises with the longer head by a common tendon ; but when, as is the ease in many quadrupeds, the biceps has but one origin from the humerus, the coraco-brachialis is in no way connected with that muscle.\nMuscles of the forearm.\u2014 Flexors. \u2014 The biceps, in the generality of quadrupeds, has the same origins as in the human subjeet ; one head arising from the neck of the scapula, the other from its coracoid process : these two heads uniting form a common tendon, which is inserted into the tubercle of the radius, and, by an aponeurotic expansion into the fascia covering the muscles of the forearm ; but where the coracoid process of the scapula is deficient, as in the horse, and in the carnivora generally, the term \u201c biceps \u201d is no longer applicable to this muscle, seeing that it has but one origin from the margin of the glenoid cavity : in the rest of its course it is similarly disposed in all the mammalia.\nThe brachi\u00e6us internus (humero-cubitien) in all quadrupeds has the same arrangement as in the human subject. In the horse, the biceps and the brachi\u00e6us are by most writers named the \u201c long and short flexors of the forearm.\u201d\nExtensors. \u2014 The triceps extensor cubiti (scapulo-olecranien). is in the horse a muscle of prodigious strength, and consists of three portions similar to those named in the human anatomy the long extensor, the short extensor, and the brachialis externus (the great extensor, the middle extensor, and the short extensor ofBourgelat, and other writers on the anatomy of the horse).. There is, moreover, a fourth portion^ derived from the common tendon of the latissimus dorsi and teres major, by the intervention of which, it takes its origin from the inferior margin of the scapula.\nThe ancon\u0153us (epieondylo cubitien) exists in all quadrupeds.\nAs might be expected from the construction of the bones of the forearm, both the pronator muscles are in the Solipeda entirely wanting, as is the case in the Ruminantia and in the Pachydermata generally ; nevertheless, in the elephant and in the hog-tribe the pronator teres is feebly developed ; and, as the mobility of the bones of the forearm becomes more perfect, as in the Carnivora, Quadrumana and Marsupialia, both the pronators are found presenting the same arrangement as in the human body.\nThe supinators are quite obliterated in the Solipeda, as well as in the Ruminantia and Pachydermata.\nMuscles of the carpus and metacarpus. \u2014 The muscles employed in bending the wrist are in our own persons the palmaris longus, the flexor carpi radialis longior, the flexor carpi radialis brevior, the extensor carpi radialis, the flexor carpi ulnaris, and the extensor carpi ulnaris ; of these one only is inserted into the carpus, all the rest being attached to the metacarpal bones.\nIn all multi-digitate mammalia, such as the Quadrumana, Carnivora, Rodentia, and Eden-\n3 a 4","page":727},{"file":"p0728.txt","language":"en","ocr_en":"728\nSOLIPEDA.\ntata, these six muscles exist and are disposed pretty nearly as in the human race; but in the Pachydermata and Ruminantia there is but one flexor carpi radialis. In all the above multidigitate animals, the muscles derived from the external condyle, and its vicinity by their co-operation, approximate the back of the hand towards the forearm, or, in other words, are extensors of the fore-foot ; while those derived from the internal condyle have a contrary effect, and act as flexors of the hand. Should the flexor and extensor of the same side of the limb act together, the hand will be bent laterally in the corresponding direction.\nIn the Solipeda, where the movements of the wrist are strictly limited to those of flexion and extension, the disposition of these muscles is considerably modified.\nThe extensor carpi radialis is here single, arising from the anterior part of the external condyle of the humerus, and from the external surface of that bone for a considerable distance: it forms a strong fleshy belly, terminating in a powerful tendon, which runs to be inserted into the base of the anterior surface of the metacarpal or cannon bone. This muscle, called by Bourgelat the \u201c extenseur droit anterieur du canon,\u201d seems, from the extent of its origin, to represent the long supinator and the two radial extensors of the wrist combined, and all three made to cooperate in the extension of the wrist.\nThe flexor carpi radialis (epitrochlo-meta-carpien) arises from the external condyle of the humerus, and is inserted into the posterior surface of the base of the cannon bone, forming the antagonist to the preceding muscle : this is the \u201cfl\u00e9chisseur interne du canon\u201d of Bourgelat.\nThe flexor carpi ulnaris (epitrochlo-carpien*) arises from the posterior part of the external protuberance of the os humeri, and also by a distinct head from the protuberance situated above the internal condyle ; its tendon is inserted into the representative of the pisiform bone and also into the root of the rudimentary metacarpal bone beneath it : this is the \u201c fl\u00e9chisseur oblique du canon \u201d of Bourgelat.\nThe extensor carpi ulnaris (cubito-sus-m\u00e9tacarpien) arises from the posterior part of the external condyle of the humerus, and is inserted, like the preceding, into the os pisiforme, whence it is prolonged beneath the carpus, so as to perform the office of a flexor of the wrist (\u201c fl\u00e9chisseur externe \u201d Bourgelat.)\nThe palmaris longus does not exist in the Solipeda ; nor is it found in the Pachydermata and Ruminantia, being in these orders of quadrupeds apparently combined with the flexor sublimis digitorum, as is likewise the case with this muscle in the bear, the badger, and the dog ; in all other unguiculate quadrupeds it is disposed as in the human subject.\nMuscles of the hand. \u2014 The extensor communis digitorum (epicondylo-sus-pha/angettien commun \\ \u2014 This muscle in the horse is called\nby Bourgelat \u201c l \u2019extenseur anterieur du pied, \u201d and by Lafosse, \u201c /\u2019extenseur du pied it arises from the external condyle of the humerus and from the contiguous fasciae, also from the upper and lateral part of the radius ; its fleshy belly is strong, and terminates in a single tendon, which runs over the foot to be inserted into the last phalanx or coffin-bone, having previously given off a slip to join the tendon of the extensor minimi digiti.\nFig. 502.\nMyology of the Horse. (After Stubbs.)\nHead. \u2014 a, Orbicular muscle of the mouth ; g, elevator of the chin ; 5, arteria angularis ; 6, arteria temporalis.\nNeck.\u2014 /, Obliquas capitis inferior ; 7, ligamen-tum nuch\u00e6.\nTrunk. \u2014 nn, Transversalis abdominis ; t, sphincter ani.\nLeft anterior Extremity. \u2014 w, Insertion of bra-chialis anticus ; d, flexor profundus digiti ; p, flexor carpi radialis ; u, ligaments of the' carpus ; l, m, tendon of the flexor sublimis perforatus.\nRight anteiinr Extremity. \u2014 l, m, Tendon of the flexor sublimis ; i, insertion of flexpr profundus into the coffin bone ; r, flexor brevis digiti pedis.\nLeft posterior Extremity. \u2014 p, adductor magnus temoris ; 7, vastus internus ; u, gracilis ; 13,15, plantaris ; 28, flexor longus digiti pedis ; 16, external malleolus; 17, Internal malleolus; 18, division of the tendon of plantaris, to allow the tendon of the flexor profundus to proceed to its insertion at 31, into the coffin bone; 11, flexor brevis digiti pedis; 36, obturator artery ; 37, nerves to the tibialis anticus.\nRight posterior Extremity. \u2014 c,Tranversalis penis ;","page":728},{"file":"p0729.txt","language":"en","ocr_en":"SOLIPEDA.\n729\nf, glut\u00e6us internus ; b, iliacus internus ; 10, vastus internus ; 33, sciatic nerve ; 23, poplit\u00e6us ; 25, 26, tibialis posticus ; 28, 29, 30, 31, flexor longus digiti pedis ; 24, poplit\u00e6al nerve ; 38, posterior tibial nerve ; 40, articular ligaments of the knee ankle and pastern joints; 26, insertion of the tendon of the tibialis posticus into 29, that of the flexor longus digiti pedis; 11, flexor brevis digiti pedis; 31, insertion of the tendon of the flexor longus into the coffin bone ; 41, internal cartilage of the hoof.\nThe extensor proprius minimi digiti. \u2014 In the horse this muscle is represented by two muscles. One of these, called by Bourgelat the lateral extensor of the foot, and by Lafosse the extensor of the pastern, is inserted by the intervention of a strong tendon into the side of the first phalanx of the solitary toe that forms the foot. The second muscle, placed between the above and the preceding muscle, furnishes a similar tendon, which, after passing in front of the carpus, becomes united at an acute angle with that of the former, the two co-operating with each other in extending the foot.\nIn the Ruminantia likewise this muscle is disposed after two different manners. In the Cervid\u00e6 or deer tribe, in which the rudimentary toes are capable of distinct movements, it furnishes two tendons to the two outer toes ; whilst in oxen, goats, sheep, and antelopes its tendon presents a double insertion\u2014 one into the posterior aspect of the outer finger, the other into the tendon of the extensor communis.\nThe extensor proprius indicis and the two long extensors of the thumb are, in all the ungulate quadrupeds, entirely wanting.\nThe abductor longus pollicis is present in all the mammalia, even in the Ruminantia and the Solipeds. In the horse its tendon is implanted into the internal surface of the base of the cannon bone, so that it thus becomes an extensor of the foot (rextenseur oblique du canon of Bourgelat).\nThe flexor digitorum sublimis perforatus and the flexor profundus perforons. \u2014 In the horse these muscles arise in common from the internal protuberance of the os humeri, and the two are confounded together for a considerable distance, when the two muscles separate to form two distinct tendons ; of these, that belonging to the flexor sublimis runs beneath the annular ligaments of the carpus, to be inserted into the base of the great pastern bone previously dividing to give passage to the tendon of the profundus on its way to be implanted into the last phalanx or coffin bone of the foot.\nIn the ungulata the small muscles of the hand would evidently be useless, and accordingly in the horse all traces of them are lost, their place being supplied by the peculiar structure of the foot, to be described further on.\nPosterior Extremity\u2014 Muscles of the Pelvis. \u2014The muscles specially belonging to the pelvis are the quadratics lumborum and the psoas parvus, which in quadrupeds offer precisely the same arrangement as in man.\nMuscles inserted into the os femoris \u2014These\nare similarly disposed in all the Mammifera possessed of a pelvic extremity, the only differences observable being in their proportionate sizes. In the Solipeda the analogue of the glut\u00e6us maximus is so small, in comparison of the two other glut\u00e6i, that it is named by Bourgelat \u201c le petit fessier,\u201d and by Stubbs the glut\u00e6us externus. In the human subject the comparative large size of this muscle is rendered necessary in consequence of the erect attitude of the body, which it principally assists in maintaining; whilst in quadrupeds, from the horizontal position of their bodies, it becomes of very secondary importance. In the horse it is a comparatively slender muscle, deriving its principal origin from the sacral fascia, but also reinforced by a long slender fasciculus, which descends immediately from the upper portion of the ileum. Its insertion is into the third trochanter and external rough surface at the upper part of the thigh bone, and also by strong tendinous aponeuroses into the fascia lata.\nThe Glut\u00e6us m\u00e9dius is the principal muscle in this region ; it arises extensively from the sacro-iliac aponeurosis, and from the external surface of the ileum, from which origin it runs downwards and forwards to be implanted into the outer surface of the great trochanter, and is, moreover, prolonged, by means of a strong posterior fasciculus, towards the lower extremity of the femur. From this latter circumstance, as well as from its preponderating strength, the glut\u00e6us m\u00e9dius may be regarded as being, par excellence, the kicking muscle in these quadrupeds which instinctively have recourse to this mode of defence as best suited to their organization.\nThe other muscles inserted into the great trochanter\u2014-namely, theglut\u00e6us minimus, the quadratus femoris, the obturator externus, the obturator internus, the gemelli, and the pyramidalis\u2014present in all quadrupeds a disposition similar to that which they have in the human body.\nThe muscles passing between the pelvis and the lesser trochanter, and also those that arise from the pubis to be implanted into the internal surface of the thigh, in the generality of quadrupeds, correspond very accurately with those of man. In the horse these are the psoas magnus, the iliacus, the pectin\u00e6us, and the triple adductor, none of which offer any peculiarity worthy of remark.\nThe flexor muscles of the leg are the biceps flexor cruris, the semimembranosus, the semi-tendinosus, the sartorius, the gracilis, and the poplit\u00e6us, all of which are enclosed by the dense fascia of the thigh, or fascia lata, which is kept tense by the action of a special muscle named the tensor vagin\u00e6 femoris.\nThe last-named muscle, called also the musculus fasci\u00e6 lat\u00e6 (ileo-fascien) arises in the horse from the anterior portion of the crest of the ileum, whence it descends obliquely downwards, enclosed between two layers of the fascia, covering the thigh, into wh ch it is strongly inserted.\nThe extensor muscles of the thigh\u2014v z. the","page":729},{"file":"p0730.txt","language":"en","ocr_en":"730\nSOLIPEDA.\nbiceps (ileo-rotulien), the vastus internus, the vastus externus, and the cruralis \u2014 offer in all quadrupeds the same general disposition as in man, the three last forming one great common muscle (trifemoro-rotulien). The anterior margin of the thigh in the horse and in other quadrupeds is formed by the sartorius (ileo-pi'etibien), which here, from its position and office, has been named by hippotomists the \u201c long adductor of the thigh\u201d\nFig. 503.\nDeep muscles o f the thigh and ligaments of the posterior extremity of the Horse.\na, h, c. A muscle named by Stubbs \u201c musculus parvus in articulatione femoris situs : it arises by a flat tendon (i), from above the tendon of the rectus cruris (d), and is inserted tendinous into the os femoris (c) ; i, k, l, iliacus internus. The small numerals indicate the principal ligaments of the limb.\nThe biceps (isch'o-peronieii) in the horse and the greater number of quadrupeds, not even excepting the quadrumana, arises by a single origin, which is derived from the ischium, and the neighbouring ligaments and fascial expansions. This muscle covers a large proportion\nof the outer surface of the thigh : its principal insertion is into the head of the fibula, but it likewise throughout its whole length contracts extensive and important attachments with the fascia lata, so that it also becomes a powerful extensor of the thigh. There is moreover, in the horse and in the Ruminantia, a distinct portion of the biceps derived from the sacro-sciatic aponeurosis, the fibres of which are directed obliquely from before backwards, which, meeting the ischiatic portion at an angle, form with it a kind of raphe, which is prolonged for some distance. This muscle is called by Bourgeiat the \u201c vastus longus \u201d of the thigh.\nThe gracilis (pubio-pretibien) is in all quadrupeds a very considerable-muscle, more especially in such as have the thigh much shortened, as is the case in the horse, and the ungulata generally. It is called by Bourgeiat the \u201c short adductor of the thigh,\u201d whilst he gives the name \u201c gracilis \u201d to the semitendinosus.\nThe semimembranosus (ischio-sous-tibien) and the semitendinosus (ischio-pretibien) have in all quadrupeds the same origin and general arrangement as in man ; but both of them are in the lower animals inserted into the tibia by a broad aponeurosis. It must also be remarked that their insertion extends much lower down than in the human subject, a circumstance which causes the leg to be permanently kept in a semiflexed condition ; and is one of the great obstacles to their walking in an upright position. Even in the Quadrumana these muscles have their insertions very low down in the leg.\nThe poplitceus has nothing remarkable in its disposition.\nMuscles implanted into the foot. The gas-trocnemii (bi-femoro-calcanien) and the sol\u0153us (tibio-calcanien) are less considerable muscles, as regards their comparative size in quadrupeds, than in the human race : nevertheless their general disposition is invariably the same as in man. In the Solipeda, the sol\u0153us is remarkably slender and feeble.\nThe plantaris (femori-calcanien). \u2014 In the Solipeds this muscle is remarkably developed, so much so indeed as apparently to represent the flexor sublimis. In the horse this muscle arises under the external head of the gemellus from a large fossa in the os femoris above the external condyle : its tendon is continued downwards, and runs over the extremity of the os calcis, where it is enclosed in a sheath formed by strong ligaments, which prevent it from slipping out of its place; passing on from this point, it divides, to be inserted upon each side of the posterior surface of the great pastern bone towards its inferior extremity, here giving passage between its two insertions to the tendon of the long flexor of the toe, which it serves to bend down closely to the pastern when the fetlock joint is bent, thus seeming to perform the functions both of the plantaiis and of the short flexor of the toes.\nThe tibialis anticus. \u2014 In the Ruminantia and in the Solipeds, the tibialis anticus is irn-","page":730},{"file":"p0731.txt","language":"en","ocr_en":"SOLIPEDA.\n731\nplanted into the anterior surface of the base of the metatarsal or cannon bone, so as to be simply an extensor of that portion of the foot which in these animals is usually misnamed the leg.\nThe tibialis posticus is altogether wanting in the Solipeds, as also in the Ruminantia and the hog-tribe.\nThe three peronei are, in the horse, represented by a single muscle, the tendon of which becomes conjoined with that of the long extensor of the digit, with which, when in action, it co-operates.\nMuscles inserted into the digit. \u2014 The abductors and adductors * are the abductor pol-licis, the adductor obliquas pollicis, the adductor transversales, the abductor minimi digiti, and the interossei.\nThe flexor muscles in the horse are necessarily reduced to a state of extreme simplicity ; the short flexor communis is entirely wanting ; the plantaris, as described above, considerably increased in importance, has a double insertion into the base of the great pastern bone, and presents a similar disposition to that of the flexor perforatus in digitate quadrupeds, while the flexor communis longus perforans, here reduced to a single tendon, appropriated to the solitary toe, passes on as usual to be inserted into the last phalanx.\nThe flexor longus pollicis exists both in the Ruminantia and Solipeda, notwithstanding the total absence of a thumb in these animals ; but, instead of its usual destination, it here becomes affixed to the tendon of the flexor communis perforans, to which it forms a powerful auxiliary.\nThe extensor muscles of the toes in all digitate quadrupeds, provided with a representation of the great toe in the human foot, resemble those of man : in other animals there are some peculiarities that require notice. In the Quadrumana, the three muscles found in the human foot are present ; but in addition to these there is a proper abductor of the thumb (adductor, as it would be called by the anthropotomist), situated upon the inner side of the extensor pollicis longus, of which no traces exist in mankind.\nWhere the inner toe is wanting, as in the dog and the rabbit, the extensor pollicis is likewise deficient.\nIn the cloven-footed quadrupeds there is a proper extensor to the inner toe representing that of the thumb, and the peroneus longus, which is inserted into the external toe, performs the office of extending that also : there is moreover in Ruminants a long abductor of the thumb, the tendon of which is inserted close to that of the tibialis anticus\nIn the Solipeds, the extensor communis\n* In comparative anatomy, owing to the permanently prone conditiohof the hand and foot of animals, it is impossible to employ the terms abductor and adductor, external and internal, &c., in the same sense as the anthropotomist: by abductors we therefore mean muscles which separate the external from the middle fingers, by adductors those which bring the fingers more closely together.\n(peroneo-sus-onguien) terminates in a single tendon, which is inserted into the, dorsum of the last phalanx of the foot: it receives, however, in transitu, a few fleshy fibres derived from the cannon bone, which represent the extensor brevis of unguiculate quadrupeds.\nIn the Solipeda, as might be expected, the abductors and adductors of the toes are entirely wanting.\nMuscles which act immediately upon the lower jaw. \u2014 These are the masseter, the temporal, and the two pterygoidei, which in all quadrupeds have the same general arrangement as in human beings.\nMuscles of the oshyoides. \u2014 The os hyoides of the Solipeds is constructed in accordance with a plan common to the Ruminants, and many Pachydermatous quadrupeds. Its body is arched and broad, presenting in the middle of its fore part a simple tubercle, and a tolerably long apophysis. It is consolidated with the superior cornua, which together form a very open arch. The single piece forming the anterior cornu is articulated to a rounded tubercle, situated just in front of the union between the posterior cornua and the body of the os hyoides, so as to admit of a considerable degree of motion in this joint. At its termination it is connected to the styloid process, which is very long and slightly forked.\nThe movements of the os hyoides are effected by numerous muscles, derived from several sources, the general arrangement of which, in most quadrupeds, conforms pretty nearly with what occurs in the human species.\nThe sterno-hyoideus exists in all quadrupeds, or, at least, is represented by a muscle of correspondent effect, derived from the sternum. In the Solipeda and in Ruminants, the sterno-hyoideus and the sterno-thyroideus form but a single muscle, which divides, to be inserted into both the larynx and os hyoides.\nThe omo-hyoideus in the horse is a very strong muscle, resembling in its origin that of the human subject ; but in some ruminants, as, for example, in the sheep, the analogue of the omo-hyoideus is derived from the transverse processes of the inferior cervical vertebrae.\nThe genio-hyoideus and the mylo-hyoideus have nearly the same arrangement in all mam-miferous quadrupeds.\nIn the horse, all three of the above muscles are present. The stylo-hyoideus furnishes a sheath to the longer portion of the digastricus, and extends from the furcate extremity of the styloid bone to the base of the posterior corner of the os hyoides : this is the \u201c grand cerato-hyoidien \u201d of Gerard. There is also a \u201c cera-toidien lateral \u201d (cerato-hyoideus) of Girard, extending between the corner of the os hyoides and that of the thyroid cartilage.\nThirdly, there is the mastoido-styloideus (stylo-hyoidien of Gerard), a short thick muscle, derived from the long pyriform apophysis of occipital bone, whence it descends towards the angle of the styloid bone, into","page":731},{"file":"p0732.txt","language":"en","ocr_en":"732\nSOLIPEDA.\nwhich it is inserted, above the origin of the stylo-hyoideus.\nThe other muscles of this region exhibit no peculiarities worthy of notice.\nThe muscles of the tongue, of the palate, and of the larynx, are in most quadrupeds strictly comparable to those of the human species.\nMuscles of the Face. \u2014 These, from the conformity of their general arrangement with what exists in man, are distinguishable by the same names as are employed in human anatomy.\nFig. 504.\nFacial Muscles of the TIorse. (After Sir CharlesBell. )\na, orbicularis palpebrarum ; b, d, cutaneous slips which raise the outer and the inner commissures of the eyelids ; c, depressor of the lower eyelid ; e, zygomaticus ; f g, levator anguli oris al\u00e6que nasi ; h, elevator of the upper lip ; i, dilator na-rium ; k, nasal cartilage ; l, m, orbicularis oris ; n, masseter.\nThe epicranius, or occipitofrontalis, exhibits the usual origin from the posterior part of the cranium, whence, running forwards, it covers the skull with its tendinous aponeurosis, and, in front, spreads in muscular slips upon the forehead, some of which (fig. 504. /) extend downwards, to spread over those of the orbicularis palpebrarum.\nSituated upon the outer side of the orbit there is another descending slip of muscle (fig.504.d), apparently derived from the lateral muscle of the cartilage of the ear which, by elevating the external canthus of the eye,\ncontributes much to the expression of that organ.\nThe orbicularis palpebrarum (fig. 504. a a) arises, as in the human subject, from the commissural ligament at the inner canthus of the eyelids, whence it winds round the orbit, its lower fibres receiving attachment from the os lachrymale.\nInternal to the last-named muscle are a few fibres, that represent the corrugator supercilii.\nThe Levator anguli oris (fig- 504. f g) is, likewise, extensively inserted into the upper lip and margin of the nostril : it has two origins, derived from the surface of the superior maxillary bone, between which the lateral dilator of the nostril and upper lip passes to its destination.\nThe depressor of the lower eyelid (fig. 504. c) is a short muscular slip, the use of which is sufficiently indicated by its name.\nThe zygomaticus (fig. 504. e) is a depressor of the external angle of the eye, as well as an elevator of the corner of the mouth, its fibres being intermixed with those of the orbicularis palpebrarum, as well as of the orbicularis oris.\nThe long dilator of the nostril, and elevator of the upper lip (fig. 504. i), arises at a little distance below the inferior margin of the orbit ; and, passing between the two origins of the levator anguli oris, terminates in a tendon, which becomes connected with that of the opposite side, and then spreads out in front of the upper lip.\nFrom the tendon of the last muscle arises the anterior dilator of the nostril (fig. 504 h ), which, acting upon the interior nasal cartilage, powerfully expands the aperture of the nose.\nThe other muscles \u2014 viz. the orbicularis oris, the levator labii superioris, the elevator of the chin, and the depressors of the lower lip, and angle of the mouth \u2014 need no particular description.\nAlimentary Apparatus. Teeth. \u2014 The dental formula common to the Solipeda is as follows : \u2014\nT .\t3\u20143\t. l-l\nIncisors ^ canine j\u2014^\tpremolars,\n3\u20143\t,\t3\u20143\n3Z-3\u2019 mo>ars, 3ZI3\tThe canine teeth,\nhowever, it must be observed, only exist in the male sex.\nThe incisor teeth, in the generality of herbivorous quadrupeds, are bevelled off posteriorly, so as to present in front chisel-like cutting edges ; but in the Solipeds, when young, the lateral incisors are furnished with two cutting edges, one in front and the other behind, from which circumstance those central fossae are produced which, as we shall see further on, furnish important testimony relative to the age of the animal.\nThe canine teeth, here called \u201c tusks fi or \u201c tushes,\u201d are always of very moderate dimensions, and their points, at an early age, become flattened and blunt. Those of the upper jaw are separated from the incisors by a con-","page":732},{"file":"p0733.txt","language":"en","ocr_en":"SOUPED A.\n733\nsiderable interval ; and a similar interspace also exists, but to a less extent, in the lower jaw.\nThe molar teeth of the horse are of a prismatic form, their grinding surfaces being marked with four crescents of enamel in the lower jaw, and with five in the upper: these crescentic patches in the upper jaw have their concavities turned outwards, but in the lower jaw in the opposite direction. The teeth of the horse are, moreover, distinguishable from those of the ox and some other Ruminants, which they resemble in their general appearance, from the circumstance that, in the latter, the crescentic patches of enamel are arranged in pairs, and are placed parallel to each other ; whilst in the horse they are situated alternately, the first of the inner margin of the tooth corresponding to the interval between the two of the outer margin.\nProfessor Owen* observes, that the character by which the horse\u2019s molars may be best distinguished from the teeth of other Herbivora corresponding with them in size, is the great length of the tooth before it divides into fangs. This division, indeed, does not begin to take place until much of the crown has been worn away ; and thus, except in old horses, a considerable portion of the whole of the molar is implanted in the socket by an undivided base. The deciduous molars have shorter bodies, and sooner begin to develope roots ; but in these, or in an old permanent molar with roots, the pattern of the grinding surface, though it be a little changed by partial obliteration of the enamel folds, yet generally retains as much of its character as to serve, with the form of the tooth, to distinguish such tooth from the permanent molar of a Ruminant.\nA knowledge of the structure and history of the teeth of the horse becomes additionally important, from the circumstance that it is from the condition of the dental apparatus that an estimate may be formed concerning the age of the animal ; and, in order to understand the data thus afforded, it will be necessary to consider the structure of these organs rather more closely.\nThe incisors f, when the permanent teeth are first completely developed, are arranged close together, forming the arc of a circle at the extremity of both jaws ; they are slightly curved, with long simple sub-trihedral fangs, tapering to their extremity. The crowns are broad, thick, and short; the contour of the biting surface, before it is much worn, approaching an ellipse. These teeth, if found detached, recent, or fossil, are distinguishable from those of the Ruminants by their greater curvature, and from those of all other animals by a fold of enamel, which penetrates the body of the crown from its broad flat summit, like the inverted finger of a glove. When the tooth begins to be worn, the fold forms an island of enamel, inclosing a cavity partly\n* Odontography, p. 574.\nf Owen, Odontography, p. 572.\nfilled with cement, and partly by the discoloured substances of the food, and is called \u201c the mark.\u201d In aged horses the incisors are worn down below the extent of the fold, and \u201cthe mark\u201d disappears. The cavity is usu-\nFig. 505.\nFig. 506.\nTwo-years'-old ; milk incisors, middle pair much worn\u2022 (After Youatt.)\nFg. 507.\nThree years; the two middle teeth have been shed and renewed ; the canines just appearing above the gums. (After Youatt.')","page":733},{"file":"p0734.txt","language":"en","ocr_en":"SOLIPEDA.\n734.\nF'g. 508.\nFour years ; four teeth have been shed and renewed. (After Youatt.')\nFig. 509.\nFive years ; all the incisors have been shed and renewed; the middle pair much worn,\t(After\nYouatt. )\nally obliterated in the first, or mid-incisors, at the sixth year ; in the second incisors at the seventh year, and in the third, or outer incisors, in the eighth year, in the lower jaw. It remains longer in those of the upper jaw, and in both the place of the \u201c mark \u201d continues for some years to be indicated by the dark-coloured cement, even to about sixteen years old. At this period the worn summits of the incisors present a subtriangular form.\nThe canine teeth are small in the horse, and rudimentary in the mare ; the unworn crown is remarkable for the folding in of the anterior and posterior margins of enamel, which here includes an extremely thin layer of dentine. The representative of the first premolar in the first set of teeth is a very small and simple rudiment, and is soon shed. The three normal premolars are as large and complex as the true molars, the anterior one being usually the largest of the series in the upper jaw.\nSalivary Glands. \u2014 The salivary apparatus in the Solipeda is very extensive, perhaps more\nso than in any other class of quadrupeds, consisting of large glandular masses divided into numerous lobes and lobules of a pale colour, and but loosely connected together by cellular tissue.\nThe Parotid Glands in the horse constitute a secreting apparatus, the bulk of which is extremely remarkable. Each of these glands extends from the external meatus auditoreus along the side of the head and of the lower jaw, as far forwards as the masseter muscle, and at the same time stretching deeply inwards as far as the side of the trachea. This enormous glandular organ may be considered as composed of three principal portions : each furnishing its excretory duct, which, however, soon unite to form a common canal, which at first descends within the angle of the jaw, whence, winding round the anterior edge of the masseter, it mounts up externally as far as the buccinator muscle, which it perforates nearly opposite the fourth molar tooth of the upper jaw, its internal orifice being situated in the centre of a prominent papilla.\nThe Submaxillary Glands are much smaller than the parotids. Posteriorly they consist of a thick globular portion, which is adherent to the inner surface of the parotid, but as they advance forwards, they become considerably attenuated, each terminating in its appropriate duct. The latter is of considerable length, and, after passing the sublingual gland, with which it contracts some attachments, opens into the mouth at a little distance behind the canine tooth, its opening being in the immediate vicinity of a papilla that seems to form a kind of valve at its orifice.\nThe Sublingual Glands are smaller than the preceding, and are of an oblong shape : they pour the saliva that they secrete into the cavity of the mouth through numerous orifices arranged in several rows on each side of the tongue.\nIn addition to the above large glandular* organs, there remain to be noticed the Molar Glands, consisting of numerous detached granular-looking bodies of a lenticular shape situated beneath the mucous membrane that lines the buccinator muscle, and the inner surface of the superior maxillary bone behind which they mount up into the zygomatic fossa to within a little distance of the abductor muscle of the eye.\nPharynx. \u2014 The pharynx in quadrupeds generally presents a structure very similar to that of the human race, and may be said to be composed of analogous muscles : nevertheless its horizontal position in these animals renders the necessity for muscular exertion during deglutition greater than in man ; and, accordingly, these fibres are not only stronger in quadrupeds than in our own persons, but sometimes additional muscles are met with, by the aid of which the action of swallowing is facilitated.\nIn the horse, the muscle which represents the middle constrictor of the pharynx might more properly be called the pterygo-palato-","page":734},{"file":"p0735.txt","language":"en","ocr_en":"SOLIPEDA.\t735\npharyngeus*, its fibres descending from the pterygoid and palate bones, along the sides of the pharynx, around which they wind obliquely, uniting in the middle line upon its posterior surface, where they form a thick muscular layer.\nThe inferior constrictor, or thyro-pharyngeus, is equally broad and strong, its fleshy fibres taking nearly the same direction as they proceed towards the back of the pharynx, where they join by a median raphe.\nIn addition to the above, there is a crico-pharyngeus, arising from the posterior and inferior margin of the cricoid cartilage, whence its fibres extend obliquely upwards along the sides of the pharynx.\nThe analogue of the stylo-pharyngeus is, in the Solipeds, a cylindrical muscle derived from the styloid bone, and, running from behind forwards upon the sides and upper part of the pharynx, mixes its fibres with those of the superior constrictor \u2014its action is to raise the commencement of the pharyngeal sac, which it at the same time dilates and draws backward.\nThere is likewise a small muscle derived from the middle part of the styloid bone, the fibres of which run backwards and inwards, so as to meet those of the muscle last mentioned.\nLastly, there are two other muscles, the fibres of which take a longitudinal direction. One of these, the pharyngeus proprius, arises from the tendinous middle line that extends from below the insertion of the stylo-pha-ryngei, and is prolonged downwards along the posterior and lateral walls of the oesophagus : the other, the aryteno-pharyngeus, is a small muscular band proceeding from the back part of each arytenoid cartilage, and running down the front of the oesophagus towards the stomach.\nStomach. \u2014 Tn all the Solipeda the stomach is simple, and presents little remarkable in its shape. The oesophagus (Jig. 510. b) is inserted at a very acute angle into its smaller curvature, which is, as it were, folded upon itself. The cardiac cul-de-sac (c) is very capacious,\nFig. 510.\ncc\nStomach of the Horse.\n* Cuvier, Le\u00e7ons d\u2019Anatomie Compar\u00e9e, tom. iv.\np. 606.\nand is lined throughout internally with a thick cuticular layer continuous with the lining of the oesophagus, and extends nearly as far as the middle of the stomachal cavity, where it terminates abruptly by a prominent indented edge, the interior of the pyloric half of the viscus (a, d) presenting the usual villous mucous surface. The muscular coat of the stomach consists of several superimposed layers of fibres that cross each other in different directions, some of them being apparently derivations from the muscular bands of the oesophagus ; and it is doubtless the contractions of these muscular bands, in conjunction with the obliquity of the entrance of the oesophagus, that renders the act of vomiting impossible in these animals.\nThe alimentary canal in the Solipeds is short in comparison with that of the Ruminants and some other herbivorous quadrupeds ; but this want of length is perhaps more than made up for by the enormous capacity of the large intestine, which, on first opening the body of one of these animals, seems of itself to occupy the whole of the abdominal cavity.\nCommencing from the pylorus, the duodenum (Jig. 510. f.) is found to be considerably\nFig. 511.\nCaput Coli fyc. of the Horse.\ndilated ; but its diameter soon contracts, and the rest of the tract of the small intestines is of pretty equable dimensions throughout, or if it presents constrictions here and there, they disappear when the gut is distended with air. The iliac portion of the small intestine (fig. 511. d) terminates in a c\u00e6cum of enormous bulk (Jig. 511. a, b, c, e,f ), which is separated from the commencement of the colon by a deep constriction (g) : the colon itself is throughout its entire extent proportionately voluminous, commencing in the right flank: its ample folds (Jig. 512. a, b) mount upwards as far as the diaphragm, whence they descend again, forming a viscus of vast capacity as far as the left iliac region, where, becoming gradually contracted in its dimensions, it terminates in the rectum. The ascending portion of the colon (a, b) is separated from the descending part (c, d) by a constriction ; and the latter forms a third remarkable dilatation before it ends in the rectum. The whole colon is puckered up into huge sacculi by three longitudinal muscular bands, which","page":735},{"file":"p0736.txt","language":"en","ocr_en":"736\nSOLIPEDA.\nterminate where the rectum begins, the last- small size, in which the f\u00e6ces become moulded named division of the alimentary canal pre- into balls preparatory to their expulsion, senting only a few pouches of comparatively When in a state of moderate distension, the\nFig. 512.\nColon of the Mare in Situ.\nsmall intestines of an ordinary size are found to measure about fifty-six feet in length from the pylorus to the c\u00e6cum, with a circumference varying according to the state of contraction of the bowel from two inches and a half to six inches. The c\u00e6cum is about two feet and a half long, and about two feet in circumference at its broadest part ; but towards its blind termination it assumes a conical form, and terminates in a point {fig. 511.5). Above the ileo-c\u00e6cal junction, the intestine forms a cul-de-sac {fig. 51l.e), which is bent upon itself so as almost to resemble a second c\u00e6cum separated from the rest of the colon by a deep contraction, and there is, moreover, sometimes a third globular cavity, situated as shewn in fig. 511./: but this is not constantly present.\nThe enormous colon {fig. 512. a, b, c, d), which seems of itself to occupy the whole abdominal cavity, is divided into two 'portions ; _ the first {a, b) is about 2 feet 3 inches long, and, at least, two feet in circumference ; the second portion (c, d) is\nof nearlv the same dimensions ; but towards its termination, its circumference diminishes to 10 inches, and the continuation of the bowel retains that size for the length of a couple of feet, when it again enlarges to a circumference of 2 feet 4 inches before its termination in the rectum.\nThe entire length of the colon and rectum taken together is 21 feet, which, added to the length of the small intestines, gives a total length of 77 feet for the intestinal canal, exclusive of the c\u00e6cum.\nLiver. \u2014 This viscus in the horse is divided pretty equally between the left and the right sides of the body. It is divided into four lobes, measures about a foot and a half in its greatest diameter, and weighs between four and five pounds. There is no gall-bladder ; but the hepatic duct is extremely capacious, and evidently forms a receptacle for the biliary secretion.\nSpleen. \u2014 The spleen of the horse has the shape of an elongated triangle, situated, ob-","page":736},{"file":"p0737.txt","language":"en","ocr_en":"SOLIPEDA.\t737\nliquely, upon the left side of the stomach ; its base pointing upwards and backwards, and its apex downwards and forwards; it is about 9 inches long, 4 inches broad at its widest part, and three-quarters of an inch in thickness. Its weight is about twelve ounces.\nThe pancreas is of an irregular shape, appearing to be made up of three branches\u2014 the shortest of which terminates at the duodenum ; of the other two, one extends beneath the right, and the other reaches as far as the left kidney: these three branches form, by their union, a flattened mass, about half an inch in thickness, which may be called the body of the pancreas. There is nothing remarkable in the arrangement of its excretory duct.\nCirculatory Apparatus. \u2014 The structure of the heart and the general arrangement ot the arterial and venous systems offer no peculiarities w\u2019orthy of notice.\nStructure of the Horse\u2019s Foot.\u2014The mechanical structure of the foot of the horse demands to be considered at length, for in whatever point of view this part of their economy is regarded, either as a simple instrument of progression, or a curious piece of anatomy, it will be found equally deserving the study of the physiologist and of the veterinarian. Numerous writers have accordingly devoted their attention to this subject, both on the continent and in our own country ; but their descriptions are, unfortunately, so mixed up with terms of farriery and stable jargon, that the anatomist finds considerable difficulty in deciphering their elaborate disquisitions. Among themost philosophical English treatises are those of Professor Coleman and Mr. Bracy Clark, to both of whom we shall be indebted for many of the following observations.\nHorny hoof. \u2014 The whole exterior conical covering of the horse\u2019s foot, called in technical language the \u201c wall of the hoof,\u201d is formed of a dense horny substance, which in shape resembles a hollow cone obliquely truncated at its upper part, so that the hoof is deepest or highest in front of the foot, diminishing in this respect as it recedes backwards towards the \u201c quarters ; \u201d it then loses, to a considerable extent, its conical shape, and becomes nearly upright, especially on the inside or inner quarter, still growing narrower or lower to the posterior extremity of the foot, where, at first sight, it appears to terminate by mixing with the substance of the \u201c frog,\u201d hereafter to be described, and with the integuments of the posterior region of the foot : instead of terminating in this manner, however, a more accurate examination shows it to be suddenly inflected inwards, pursuing its course towards the centre of the ffcot, where, diminishing gradually in depth, it is finally lost, becoming mixed up with the \u201c sole,\u201d near the point of the frog, thus forming a distinct and remarkable internal wall that supports the under parts of the foot, and at the same time protects, by its bold projection, the sole and the frog from an undue degree of pressure and contusion against the ground.\nThe parts thus formed by a continuation of\nthe wall of the hoof beneath the foot, are called the \u201c bars of the foot,\u201d and are frequently described with, and taken for, part of the \u201csole.\u201d The direction of this sloping floor serves to throw all superincumbent pressure outwards towards the sides of the foot, and at the same time leaves a triangular space, posteriorly, for the insertion of the frog (fg. 513.), which it likewise protects from injury.\nFig. 513.\nStructure of the hoof of the Horse.\n1, the sole ; 2, section of the horny hoof ; 3, upper surface of the frog ; 4, 4, the horny heels ; 5, Bars of the foot; 6, walls of the hoof; 7, 8, 9, 10, 11, boundaries of the vaulted space, .in which the frog is lodged ;, 12, 12, the sensitive foot.\nThe wall thus constructed appears to form the basis of the mechanism of the hoof, to which all the other parts are subordinate, and, if so understood, will much facilitate our views of the nature and economy of its structure. Its inner surface is every where lined, as it were, with numerous elastic lamellas that project internally, and arranged in parallel lines, proceeding downwards perpendicularly towards the front of the foot (fig. 514,3.) : these horny laminae are, at least, five hundred in number, and afford, from the aggregate surface that they present, a very extensive superficies for the attachment of an equal number of similar processes, derived from the vascular surface that covers the coffin bone, with which they interdigitate in such a way that the pressure to which the foot is subjected, which if concentrated upon a small surface would in-\n3 B","page":737},{"file":"p0738.txt","language":"en","ocr_en":"738\nSOUPED A.\nevitably cause the destruction of living tissues, becomes so diffused as to produce no inconvenient results.\nThe horny lamell\u00e6 above alluded to, when removed from the hoof, have little or no elasticity when drawn in a longitudinal direction; but when drawn transversely, they possess this quality in a very remarkable degree, more especially in resisting pressure applied in a direction outwards and downwards, to resist which, the arrangement of their fibres is, on close examination, found to be particularly adapted.\nThe whole horny hoof, if unravelled by maceration or long continued exposure, is found to be essentially composed of longitudinal corneous threads or hairs matted, and, as it w ere, strongly glued together, \u2014 a structure preeminently adapted to combine all the requirements of strength, elasticity, and toughness.\nAs it approaches the quarters and heels, the horny helmet encasing the foot diminishes in its thickness as well as in height, affording, by this means, a degree of pliancy, which here becomes as necessary as firmness and unyielding solidity were in the front of the organ ; yet, even here, by the doubling in of the hoof towards the sole, a strong horny margin is left, which is admirably adapted to receive the principal bearing of this part of the foot, and to protect and defend the sole enclosed within its curvature.\nFrog. \u2014 The triangular chasm left by the inflections of the wall towards the centre of the foot, is filled up by a very remarkable organ, named, in the language of farriery, the \u201c frog,\u201d either from some fancied gross resemblance which it bears to that animal, or, more probably, by corruption, from the French \u201c fourche \u201d or \u201c fourchette,\u201d Anglic\u00e8 \u201c fork,\u201d applied to the same structure. By Latin writers, it is generally known under a similar appellation, \u201c furca,\u201d and by the Greeks was named \u201c xfAiSora,\u201d from a similarity between its shape and that of a swallow.\nThis body, which externally has the appearance of a triangular mass of elastic horn, may not be inaptly compared to an elastic key-stone received into an elastic arch communicating in some cases, and admitting in all, the springing movements of which such an arch would be capable. Its bar, which, towards the heels, is thin and broadly spread out, possesses a considerable degree of flexibility, which is gradually lost in approaching the centre of the foot, where there is less occasion for movement.\nThe base of the frog lies between and connects together the two posterior incurvations of the hoof ; it then passes over and en-ve'opes those parts, restraining their action. The sides of the frog are united by applied surfaces to the upper edge of the arch formed by the sole, or more truly the bar formed by the continuation of the wall. Its point extends to or beyond the centre of the sole.\nThe frog recedes from pressure in the natural foot,\u00b0by having its level within the level\nof the other parts of the under surface of the foot, taking a third rate or degree of bearing upon the ground : the wall first ; the bar next projecting beyond it : its base also retires further from pressure than the other parts of it, and is protected by the projecting angles of the horny or lower heel.\nOn either side, the frog is bounded by deep longitudinal excavations or channels, named the commissures of the frog ; the bottom or deepest part of these channels, forming the line of umon of the frog with the bar, a space is thus afforded on either side of the frog, which, as an elastic body, would have been useless without it; for in vain would elasticity have been given to any part, unless sufficient room was also given for its expansion. Towards the heels, these commissures are of considerable width, and they are there arched over by horny prolongation, from the base of the frog, named the arch of the commissure. The other extremity of the commissure growing, by degrees, shallower, is lost in the level of the sole, before it approaches the arch of the frog.\nSeen from without, the frog makes a bold projecting appearance, as though it were a solid body of horn ; and the smiths, deceived by this appearance, entertain but indifferent notions of its real structure, and use their paring knives upon it much more freely than its thickness warrants; for it is in reality only an inverted arch of horn that is turned downwards and reversed in respect to the general arch formed by the sole and bar, so that its real thickness in horn is by no means so considerable as on a first view it W'ould appear to be.\nExamined from within\u2014that is to say, w hen the foot has been drawn forth from the hoof\u2014 the frog presents an inverted triangular arch, so intimately connected w ith the bar and sole, that no one would suspect it of being a distinct or divisible part, one uniform uninterrupted surface being everywhere observable on this inside : it may, however, be exhibited as a distinct inserted part by making a horizontal section of the foot through the union of the bar with the side of the frog, when the difference of their structure and appearance, and the line of their applied surfaces become sufficiently visible and distinct. A hoof exposed to the weather will also be seen in its decay to separate at this part first, and thus readily show its distinctness from the rest of the hoof.\nIn a perfect, well-formed foot, undistorted by shoeing, Bracy Clark observes that \u201c the base of the frog occupies a certain division of the general circle of the hoof, and that this division is about a sixth part of the whole circumference. By knowing this fact we are not only led to entertain more just notions of the form of the foot and the proportions of its parts, but it affords us also an easy means of forming a pretty accurate guess of what injury or diminution the foot has sustained at any period of the life of the horse without previously seeing the original state of the frog.\u201d","page":738},{"file":"p0739.txt","language":"en","ocr_en":"SOLIPEDA.\t739\nThe wings or lateral processes above described, as extending from the base of the frog, not only enclose the posterior ends or doublings in of the hoof, but the same horn is continued around the whole upper edge or margin of the roof, forming a broad convex band, whose upper edge, projecting higher than the hoof itself, receives and covers over the terminating edge of the skin, where it meets the hoof, and thus protects this part from external injuries, to which it would otherwise be liable. Posteriorly it is of considerable breadth, and firmly connects the frog with the upper part of the slope of the horny heels, over which it likewise expands. This structure, first described by Bracy Clark, received from him the denomination of the \u201c coronary frog-band.\u201d\nIn the centre of the frog, as viewed from the sole, is a considerable cavity, the edges of which are furnished with rising lips or prominent margins of the horn ; this hollow is termed the cleft of the frog, and extends to a considerable depth. This cavity appears to serve the following useful purposes * : \u2014 1st. It is a safeguard from rupture between the two halves or divisions into which the foot is almost separated. 2dly. By closing when pressure comes direct upon the underside of the foot, it prevents too much condensation of the horn at this part, and consequent pressure and a too solid resistance upon the soft parts beneath. 3dly. When the foot bears partially upon the ground, as by one side only, which will happen occasionally where the surface is irregular, it can extend along with that side of the foot without rupturing, by the greater liberty it thus affords to the part, while at the same time the strength of its margin secures it from laceration. 4thly. On loose soils this indent or cavity will doubtless assist in giving the foot a firmer hold by the irregularity it offers to the surface.\nIt is, however, upon the inner aspect of the hoof that the most remarkable part of this structure is to be observed, for when examined internally it is found that the external cleft is only the hollow base of a cone of stout horn of considerable size, which passes from it directly into the substance of the sensitive frog, and which, though completely imbedded in the soft parts, is nearly or quite as hard and tough as is the horn of the exterior of the frog which is exposed to the air. This remarkable provision seems to serve the purpose of uniting more firmly the two halves of which the foot of the solipeds at this part really consists, there being here an evident tendency, in the tegumentary defences of the horse\u2019s foot, towards that division which in the ruminating quadrupeds is completely carried out. This important cone of horn Bracy Clark named the frogstay or bolt, observing that, like an inserted tooth, it more firmly holds the horny to the sensitive frog, for while the sensitive frog falls into the inverted arch of the horny frog, and is thus held most firmly in its place, this part, entering\nin the opposite direction into the sensitive frog, serves reciprocally to confirm and fix these parts together, and preserve them from external injury and dislocation. An excellent view of this piece of anatomy is obtained by making a perpendicular section of the foot extending through the \u201c heels and surrounding elastic matter.\u201d\nThe Sole. \u2014 This is an irregular plate of horn, which serves to close up the space or great inferior opening described by the lower circumference of the wall, and makes the third member or part of the hoof. It is usually of an arched form, more or less flattened, its concavity being turned to the ground, so that its centre, which is the thinnest part, is by this means removed from the degree of external pressure which the sides or bottom part of the arch have to support.\nNature has secured herself, by the arrangement of this part, in two ways from the resistance which an arch of common properties would create on becoming condensed under pressure, and forcibly resisting the load brought upon it, which would have been subversive of the leading principles of the mechanism of the hoof. In the first place the sole being cleft to its centre or beyond it by the large triangular opening formed at its posterior part, which, destroying the resistance of the arch, serves to receive the ends also of the wall of the hoof first, and is then closed and filled up by the inverted arch of the frog ; so that the ends of the hoof are thus tied in and secured from being forced asunder by the pressure from within, being thus wedged in between the frog and the sole, serving in their places the other offices already noticed, while the sole, being thus broken, has a diminished resistance in the centre.\nAgain : the lower circumference of the arch of the sole is everywhere found abutting against the sides of the wall, which are rendered sufficiently flexible outwards to yield to the weight when pressed against by the descent and flattening of the sole, so that every provision for the elasticity of the foot is thus fully secured.\nThe horse\u2019s hoof is therefore fully provided with the means of preserving its form ; but this power is unfortunately grievously interfered with by the process of shoeing ; and it is in this country at least a very rare occurrence to obtain an opportunity of examining a foot in its full-grown natural condition.\nFrom the above description of the foot of the horse it will be seen that, although when viewed in front it appears to be solid and single, the terms Solidungula and Solipes convey but a very imperfect notion of the real nature of this kind of hoof ; for though the front be solid the posterior parts possess the greatest degree of elasticity, short of being actually cloven, that can be imagined from the sole being open to its centre and filled up with the frog. In such a foot as the term Solidungula would imply, or a continuous circle of horn, no animal could long stand, much less move, without great fatigue and pain from\n3 B 2\nBracy Clark, op. cit.","page":739},{"file":"p0740.txt","language":"en","ocr_en":"740\nSOLIPEDA.\ncompression, which would soon become destructive. If it were necessary to employ any single epithet to express the real nature of this kind of locomotive apparatus, Bracy Clark suggests that the term Semifissipes, or half-cloven foot, would be less objectionable, though also not exactly true, on account of the presence of the frog, which, added to the entire hoof in front, seems to afford the most essential character of this kind of foot.\nFig. 514.\nDissection of the superficial Parts of the Horse\u2019s Foot.\n1, General integument ; 2, fatty mass, forming a cushion behind the great pastern joint ; 3, wall of the hoof turned hack, showing the vertically lamel-lated horny processes projecting from its inner surface ; 4, section of the wall of the hoof ; 5, articulation between the cannon bone and the great pastern ; 6, 6, 6, aponeurotic tissues ; 7, 7, tendon of the extensor longus digiti pedis. 3, 9, 10, the flexor tendons of the foot ; 11,12,13,14,15, expansions of the great anterior cartilage of the foot ; 1G, the coronary frog-band raised from the hoof ; 17, the vascular or sensitive hoof; 18, elastic cushion of the heels; 19, 20, 21, arteria plantaris; 22, 23, plantar veins; 25, part of the coronary venous plexus raised from its position ; 26, 27, 28, plantar nerves.\nCartilages of the Foot. \u2014 On removing the hoof there are seen immediately beneath it two large elastic cartilages ranging to a great extent along both sides of the foot. Their figure is almost too irregular for comparison ;\nbut, when seen on a lateral view of the foot, their shape may be said to resemble that of a lozenge or of a pretty fully expanded fan, fixed by its centre, which is very much thicker and more solid than the other parts, in a deep horizontal cavity or channel in the coffin bone provided for its reception ; from this central point of insertion the anterior portion of it, passing forward, nearly meets the cartilage of the opposite side in front of the foot, the great extensor tendon of the foot only separating them, with which they are likewise connected, and make a common surface. On its inside this extremity of the cartilage takes a strong adherence to the condyles of the coronary bone, and so closely surrounds the joint betwixt the latter and the coffin bone that the articulation appears to be without any capsular ligament at this part. The posterior portion of the cartilage, ranging more largely and becoming thinner as it expands itself backwards, growing at the same time more elastic in its texture, is gradually and inseparably mixed up towards the hinder part of the foot with the skin and the ligamentary elastic tissues that form the \u201cupper heels,\u201d and constitute the principal materials for elasticity in these parts. Spreading also in an upward direction to a considerable height above the hoof, it terminates by a rounded, thin, and irregular edge, which is inflected inwards over the soft interior of the foot, to which it forms a kind of roofing and defence.\nNext, this widely distributed cartilage may be observed passing downwards, and surrounding on every side the rough and knotty extremities of the heels of the coffin bone, entering and filling up its sinuosities, and taking strong adherence to these processes ; it then extends itself horizontally inwards, passing over the horny sole and bar, and, meeting the side of the sensitive frog, intimately unites with it, forming one inseparable mass, and together filling up the whole internal area described by the sides of the coffin bone. The upright or lateral portion of the cartilage forms, with this horizontal process inwards, a right angle, thus making together a hollow space or receptacle at the back of the coffin bone, that contains the spongy elastic stuffing of the heels, together with the tendons, trunks of bloodvessels, nerves &c., passing through this part to the sole of the foot. The upper surface of the horizontal process of cartilage is full of scabrous elevations and depressions that defy dissection, among which there exists a quantity of a gelatino-ligamentous material. Beneath, or to the under surface of this horizontal layer of cartilage, the sensitive sole and bar are adherent ; and, in approaching the frog, or centre of the foot, it loses its cartilaginous nature, and becomes coriaceous, or rather ligamento-coriaceous, in texture, agreeing in this with the internal frog.\nThe horizontal portion or process of the Cartilage, named by veterinary writers the \u201c stratiform process,\u201d is of greater thickness and substance than the other parts ; it is also of a coarser grain and more elastic nature ; both portions together communicate the gene-","page":740},{"file":"p0741.txt","language":"en","ocr_en":"SOUPED A.\t741\nral boundary and form to the lateral, the posterior, and inferior parts of the foot ; and when the bars or frog are thrust upwards by pressure from without, they are then acting against this same horizontal flooring, formed by the cartilage and the frog, and met by the depression of the bones of the foot forced down from the weight of the animal ; the whole can then dilate exteriorly along with the posterior and more elastic parts of the hoof.\nFig. 515.\nLongitudinal Section of the Foot of the Horse.\n1, Great pastern bone ; 2, lesser pastern or coronary bone ; 3, sesamoid bone implanted in the flexor tendon of the last phalanx ; 4, coffin bone ; 5, tendon of extensor digiti ; 6, tendon of flexor sublimus ; 7, tendon of flexor profundus ; 8, section of the posterior expansion of the great cartilage ; 9, soft cushion of the heel; 10, section of horny hoof; 11, sensitive hoof; 12, anterior section of the cartilage spreading over the coffin bone.\nThe objects attained by the introduction of this admirable structure into the foot of the soliped are various, and have been well pointed out by Bracy Clark, in his excellent treatise, to which we must refer the reader for many practical applications connected with the veterinary art, that would be foreign to the objects of the present article. First, seeing that the resistance of a solid unyielding support would have been inadmissible, the pedal cartilages are employed as a substitute for bone, and made to occupy a very large share in the composition of the hinder part of the foot ; for it will be remarked, the coffin bone, except by its extremit}', does not extend beyond the middle of the hoof {fig. 515.), the posterior shape of the foot being almost wholly communicated by the cartilage, which, passing nearly around the whole coronary circle, serves to support and convey the skin to its lodgment in the coronary concavity of the hoof. Secondly, it serves to equalise the pressure every where over the internal surface of the hoof when under the pressure of the wreight from within, during the descent of the bones\nof the foot, and, what is singular, the hoof itself is the most solid material of these hind parts of the foot.\nA more important office still remains to be explained, namely, that of supplying the coffin bone with a considerable share of its capability of motion in the interior of the hoof ; for it is to be remarked that, as the coffin bone is obliged to describe in its descent a small portion or segment of a circle, at its back part, round its centre of motion, or rather its more fixed part (for there is none of it wholly fixed), towards the front of the foot ; so this could not so well have been accomplished had the bone itself been fixed at its upper part to the processes in front of the hoof, these being too inconsiderable to afford, in that part of the bone, the extent of motion required ; but, by the intervention of an elastic cartilage between the bone and the substance of the hoof, the bone acquires greater liberty for action, and movement of its upper parts.\nThe cartilages of the foot, in old horses, not unfrequently become partially ossified, in which condition they are known to farriers by the name of ring-bones.\nSoft Parts of the Foot. \u2014 On removing the hoof, and its horny appendages situated beneath the sole of the foot, the whole subjacent surface is found to consist of a thick, villous looking, and highly vascular membrane, moulded exactly to its inner surface, to which the name of sensitive foot is generally applied ; or, according to the structures beneath which it is situated, it is sometimes divided into sensitive hoof, sensitive frog, &c. This structure is, indeed, the matrix from which the entire corneous hoof derives its origin, and is essentially similar, in its texture and functions, to the soft core upon which the hollow horns of many ruminants and the vascular secreting surfaces upon which the nails and claws of unguiculate quadrupeds are formed. Externally it presents, upon the anterior surface of the foot, the broad vascular laminae which interdigitate with the horny plates, projecting from the interior of the hoof, as described above, so as to amplify, to a very considerable amount, the extent of surface whereby the contact between the sensitive foot and the wall is effected.\nThis entire surface is richly supplied with nerves and bloodvessels, the latter of which open into capacious plexuses, that surmount the coronary margin of the hoof (fig. 514.), and, when injected, present a very beautiful appearance.\nNervous System and Organs of the Senses. \u2014 The general arrangement of the nervous system and structure of the organs of sensation offer in the class before us no peculiarities of sufficient physiological importance to require a detailed description: we append, however, figures representing the cerebral convolutions and the base of the encephalon of the horse for comparison with similar figures given in other articles.\n3b 3","page":741},{"file":"p0742.txt","language":"en","ocr_en":"742\nSOLIPEDA.\nFig. 516.\nBrain of the Horse, showing the Convolutions.\nFig. 517.\nBase of the Brain of the Horse, showing the origin of the Cerebral Nerves.\nOrgans of Generation. Male Generative Organs.\u2014 The external organs of generation in the male solipeds are remarkable for their great development, and in nearly equal proportion are these animals conspicuous for their vigorous and fruitfid generative powers, which, however, are only called into full activity at a certain season of the year, namely, in this climate, from the beginning of April till\nthe latter end of June, during which period he will efficiently serve fifteen or eighteen mares.\nThe scrotum is suspended between the thighs at a distance of about nine inches beneath the anus, whence it is prolonged forwards, to terminate in the prepuce (dg. 518\na, f e)-\nThe penis (fig. 518. b, c, d) is full a foot in length even in its undistended state, measuring from the bifurcation of the corpora cavernosa (b) to the extremity of the glans (c), which latter organ is itself nearly half a foot in length, and four inches in circumference ; its shape is cylindrical, and it is covered with a soft and smooth skin.\nFig. 518.\nOrgans of generation of the Stallion.\n(After Haubenton.')\na, the scrotum ; b, c, d, the penis ; e, the prepuce ; f f the rudimentary mamma1 ; g, the left testicle removed from the scrotum ; h, the epididvmus ; i, k, the upper margin of the testis ; l, m, vas deferens ; n, vas deferens from the opposite side ; o, o, enlargements of the vas deferens before their termination ; p, q, tendinous hands derived from the root of the tail, these, after embracing the end of the rectum, r, run along the penis, s, as tar as the prepuce, t, where they terminate ; v, the urinary bladder ; x, x, vesiculae s\u00e9minales ; y, y, Cowper\u2019s glands.\nThe testicles (one of which only (g) is represented in the figure) are of an ovoid flattened form, each being about three inches long by two inches broad, and one inch and a half thick : the epididvmus (h) issues from its anterior part, and is composed of large tubes of a yellowish colour, bound up together in","page":742},{"file":"p0743.txt","language":"en","ocr_en":"SOLIPEDA.\t743\nnumerous small bundles. Arrived at the posterior extremity of the testes, the epididymus folds back upon itself, to constitute the vas deferens ; which, at its commencement, is very tortuous, and forms a protuberance of considerable size (7). The vasa deferentia {l, in, n) are upwards of fourteen inches in length, and, during the greater part of their course, about two lines in diameter ; but towards their termination they become, for a length of about seven inches, much dilated, here measuring upwards of fifteen lines in circumference (oo). The caliber of the internal canal does not, however, expand in proportion to the dilatation of the exterior of the duct.\nFemale Organs of Generation.\u2014 The generative organs in the female solipeds offer no variations of structure from the usual type common to placental quadrupeds. The cli-to/is (fig. 519. a) is of great size, and is lodged in a cavity appropriated to its reception, situated immediately above the inferior (?. e. anterior) commissure of the labia pudendi; its glans is enclosed in an ample prepuce, above which may be observed an orifice leading into a cavity big enough to lodge a small bean. The canal of the vagina is about afoot in length, and in its capacity corresponds with the ample dimensions of the penis of the other sex.\nImmediately behind the orifice of the urethra, the mucous membrane of the vagina forms a broad fold, which is directed forwards and lies immediately over the urethral opening : the length of this fold in the adult mare is about eight inches, and, near its middle, it is upwards of an inch in breadth.\nThe urinary bladder is small in comparison with the size of the animal ; its shape is nearly round; and its circumference, when moderately distended, about a foot and a half. The urethra is remarkably short and capacious, the circumference of its canal being about three inches, while its length is only about an inch and a quarter.\nThe orifice of the utei'us (i) projects to the distance of about half an inch into the upper end of the vagina, and is of a rounded shape, encircled by a thick margin. The womb is made up of the body and two cornua, which latter, in the unimpregnated state, measure about seven inches in length.\nThe ovaria and fallopian tubes present nothing remarkable in their structure or arrangement.\nGravid Uterus.\u2014 The anatomy of the contents of the gravid uterus, and the arrangement of the membranes that enclose the foetus offer some peculiarities worthy of notice.\nThe foetus in utero in the solipeds, is enveloped in the usual uterine membranes, \u2014 the amnion, the chorion, and the allantoid ; but the disposition of these envelopes differs remarkably from what exists in the ruminants, and many other quadrupeds.\nThe urachus {fig. 520. a) issues from the umbilicus in company with the umbilical arteries and vein (5), and, in the ovum represented\nin the figure, was found at some distance from the umbilical opening to measure about five inches in circumference, beyond which point its diameter gradually diminishes, till it reaches the point at which the amnion spreads out on all sides to envelope the foetus, where it terminates by the orifice e, and is prolonged to form the allantoid, which encompasses the rest of the cord. On the arrival of the allantoid at the extremity of the cord, it extends itself upon the chorion to which it becomes adherent, lining its internal surface in such a manner, that the two seem to form but a single membrane, the inner surface of which is formed by the allantoid (g), its exterior by the chorion (h).\nFig. 519.\ntans of generation and gravid uterus of the mare. Vagina laid open. {After Daubenton.')\na, the clitoris; b, anus; c, rectum; d, posterior surface of the vagina ; e, the orifice of the urethra ; f, membrane which covers the urethral opening ; g, the canal of the urethra ; h, the bladder ; i, i, the ureters ; k. continuation of the vagina ; l, orifice of the womb ; m, f\u0153tus as seen through the transparent amnion, n ; o, portion of the umbilical cord that extends from the umbilicus of the f\u0153tus as far asp, the point where the amnion spreads out ; q, portion of the umbilical cord which extends beyond the amnion to the point r, where the chorion and the allantoid become united ; s, the allantoid ; t, the chorion seen from its outer surface ; v, a hippomanes attached by its pedicle ; x, y, chorion adherent to the uterine walls by numerous rug\u00e6 ; z, the left ovarium ; a!, the spermatic vessels.\nThe size of the umbilical cord gradually enlarges as it approaches the chorion, owing to the progressive dilatation of the vessels 1\t3 b 4","page":743},{"file":"p0744.txt","language":"en","ocr_en":"SOLIPEDA.\n744\ncomposing it as they recede from the umbilicus.\nThe allantoid in the mare does not form a closed bag, as it does in the ruminants, but lines about half of the interior of the cavity that exists between the amnion and the chorion. To form an idea of this cavity and of the space occupied by the allantoid, it will be necessary first of all to consider the amnion as a sac, in which the foetus is enclosed, and the allantoid and the chorion as forming another sac of larger size, by which the former is enveloped in such a manner, that an interspace is left between the two : this interspace is traversed by the second portion of the umbilical cord as it passes from the former sac towards the latter, and in this course, the cord is enveloped by the allantoid membrane, which subsequently invests all the interior of the second sac formed externally by the chorion.\nFig. 520.\nThe aperture of the urachus pours forth a glairy fluid of a reddish colour, which is received into the cavity, the boundaries of which are described above : this fluid has a urinous smell, especially when heated, and moreover contains certain solid bodies, which have been from time immemorial dignified with the name of hippomanes, and were by the ancients supposed to be possessed of various mysterious qualities, and magical influences.\nThe Hippomanes was considered, until a very recent period, to be a piece of flesh growing upon the forehead of the nascent foal ; and it was not until Danbenton presented a memoir upon this subject to the Royal Academy of Sciences in Paris *, that its real nature was understood. The hippomanes were then found to be merely masses, of a thick substance, of variable dimensions, contained in the allantoid cavity, which, although they might occasionally during parturition after the laceration of the membranes, become adherent to the head of the foetus, are, in reality, produced between the amnion and the allantoid membranes.\nThese bodies are very variable in their size, and frequently several are met with, the dimensions of which vary from the size of a pea to that of a large pear, some of the latter weighing as much as five or six ounces. They are composed of a viscid substance of an olive brown colour, and frequently have irregularly shaped cavities in their interior ; but they present no traces of organization. When cut into they seem to be made up of numerous superposed layers, and externally their surface is covered with floating filaments : sometimes they are found to be attached by long pedicles to the walls of the allantoic cavity ; but, whatever their shape, they are evidently merely sedimentary deposits from the fluid in which they are immersed, and indeed may be formed at pleasure by slowly evaporating the contents of the allantoic sac. These structures are indeed by no means peculiar to the horse, but are frequently met with in other animals.\nThe exterior of the chorion is everywhere in contact with the uterine walls, and in shape represents exactly the interior of the cornua uteri, upon which it is moulded, the placenta occupying the greater portion of its extent.\nMammary Glands. \u2014 It was generally believed from the time of Aristotle until a very recent period, that in the male horse there were no nipples or other rudiments of the\n* M\u00e9moires de l\u2019Acad\u00e9mie Royale des Sciences, ann\u00e9es 1751 and 1752.\nAnatomy of the gravid uteris of tile mare. (After Daubenton.)\na, the urachus emerging from the umbilical opening of the foetus, accompanied by the umbilical vein ; b, and by two umbilical arteries ; c, continuation of the umbilical cord as far as the expansion of the amnion ; d, d, e, termination of the urachus ; f, continuation of the umbilical cord ; g, g, allantois ; h, the chorion ; i, an hippomanes adherent to the allantoid by its pedicle ; k, l, m, two other hippomanes of smaller size. The other letters refer to the generative organs of the foetus (a female) shown in connection with the above parts; o, the rectum; p, the anus; q, the bladder of urine communicating with the urachus; r, r, the ureters; s, canal of the vagina ; t, orifice of the urethra ; v, first appearance of the membrane, which subsequently spreads over the urethral orifice ; x, x, the cornua uteri ; y, separation between their internal cavities ; z, z, the ovaria.","page":744},{"file":"p0745.txt","language":"en","ocr_en":"SPINAL ACCESSORY NERVE.\t745\nfemale mamm\u00e6; except, as Aristotle expresses it, in such animals as resemble their mothers* : that is to say, in other words, that there were a few exceptional cases. Subsequent authors have stated the same concerning male solipeds in general'j', although none stated in what the resemblance consisted, or where the mammae in those furnished with them were situated ; so that even Buffon asserted it as a fact, that the male solipeds had no vestiges of mammae. Daubenton, however, having previously discovered the situation of these organs in the male ass, was led from analogy to expect their presence in the horse likewise, and soon detected them, but situated in a very unusual position, \u2014 namely, upon the prepuce of the animal. The prepuce of the stallion is found to form a kind of prominent ring around the aperture through which the penis is protruded, and it is upon this circular protuberance, close to the sides of the scrotum, that the mammae are situated. These organs are two in number (^g.518.//), situated at a distance of about half an inch from each other, and are easily distinguishable from the circumstance of the skin being raised into a papilla around each nipple, in the centre of which there is a shallow depression. It would seem, however, that in old horses the presence of these rudimentary mammae becomes less apparent.\nIn the mare, the mammary glands are situated between the thighs at a distance of about nine inches in front of the vulva. The nipples are only two in number, one on each side of the mesial line, and their distance from each other is not more than an inch and a half. As in the goat and many herbivorous quadrupeds, all the lactiferous ducts form, in the base of each gland just above the root of the nipple, a large hollow cavity, which is divided by an internal septum into two chambers, one situated in front, and the other behind ; from each chamber a separate duct is derived, which passes along the nipple as far as its extremity, where it terminates. The orifices of these canals are situated, one behind, the other about a line, apart. It is owing to the presence of the reservoirs thus formed by the cavities of the mammary glands, that the lacteal secretion is permitted to accumulate in considerable quantities, until required for the nourishment of the young, or removed by human agency for the purpose of procuring the milk, which is frequently employed as an article of diet.\nBibliogkaphy.\u2014 Buffon et Daubenton, Histoire Naturelle, tom. iv. 4to. Paris, 1753. Cuvier, Anatomie Compar\u00e9e. Clark, Bract/, A Series of original Experiments on the Foot of the living Horse, 4to. 1809. Clark, Bracy, Sectional Figure of the Horse, with Remarks on certain Properties of his general Framing, 4to. London, 1813. Stubbs, George, The Anatomy of the Horse, London, fol. 1766. Bourgelat, Elemens de 1 \u2019Art Y\u00e9terinaire. Lafosse, Cours d\u2019Hip-piatrique. Vitet, M\u00e9decine V\u00e9t\u00e9rinaire, Lyons, 1783..\n(71. By mer Jones.')\n* Equi mammas non habent, nisi qui matri similes prodiere. \u2014 Arist. de Partib. Anim. lib. iv. cap. 9.\nt Solidungula mascula mammas non habent pr\u0153terea qu\u00e6 matribus similia sunt. \u2014 Rai, Synops. method. Anim. quad. &c. p. 64.\nSPINAL ACCESSORY NERVE (part of the sixth pair of the older anatomists ; part of the eighth pair of Willis ; nervus accessorius ad par vagum; nervus accessorius Willisii ; the eleventh pair of Soemmering ; the heinerve of the German anatomists). This nerve is attached to, or, as it is more commonly expressed, arises from, the lateral surface of the cervical portion of the spinal chord close to the posterior roots of the spinal nerves ; and it lies between the posterior roots of the spinal nerves and the ligamentum denticulatum. On entering the cranium by the foramen magnum, it continues to receive additional roots or filaments of origin from the medulla oblongata. It commences by a very slender filament, most generally opposite the fifth or sixth posterior roots of the spinal nerves, and in its passage upwards to the interior of the cranium, its bulk is gradually increased by additional filaments of origin from the lateral surface of the spinal chord and from the medulla oblongata. The filaments arising from the spinal chord pass upwards and a little forward to join the trunk of the nerve, so that it lies a little nearer to the ligamentum denticulatum than the attachments of the filaments forming it. After it enters the cranium by the foramen magnum, it runs forward, outward, and upward, places itself in close apposition to the posterior surface of the par vagum, and escapes from the interior of the cranium, through the foramen lacerum posterius, along with the vagus and glossopharyngeal nerves. The roots of the accessory that arise from the medulla oblongata are placed in the same line with the lower roots or filaments of origin of the par vagum; and the upper roots of the former approach so closely to the lower roots of the latter, that it is frequently difficult to say with confidence where the roots of the one nerve end and those of the other begin. (Fig. 521, 3, 5.)\nPrevious to the time of Willis, anatomists considered this nerve as constituting a part of the vagus, and to him is due the credit of first pointing out clearly the grounds on which its separation from the vagus rests. Very great discrepancy exists in the description of the origin of this nerve given by the best anatomists. This is explained, not only by the fact first pointed out particularly by Scarpa*, that its filaments of origin are attached over different extents of the spinal chord in different individuals, and sometimes to a greater extent on one side than on the other in the same individual, but also by its lower roots or filaments of origin being so slender that they sometimes cannot be accurately traced by the naked eye. Willis himself describes it as commencing by a very slender beginning near the sixth or seventh cervical nerve.f Scarpa ascertained that its\n* Abhandlung \u00fcber den zum achten Paare der Gehirnerven hinlaufenden Beinerven. In den Abhandlung der r\u00f6m. K. K. Josephinischen Med. Chir. Academie, Band i. Wien, 1787.\nf Cerebri Anatome, &c., Caput xxviii. p. 294. Amstelodami, 1666.","page":745},{"file":"p0746.txt","language":"en","ocr_en":"SPINAL ACCESSORY NERVE.\n746\nlowest root may tie attached to the spinal chord opposite the fourth, fifth, sixth, or seventh cervical nerve, but more frequently between the fifth and sixth ; and that when its roots are extended over a more limited portion of the spinal chord, this is compensated for by their being proportionally stronger.*\nAnatomists have differed as widely in their account of the particular column or tract of the spinal chord to which the roots of the spinal accessory are attached, as they have done regarding the extent of the spinal chord over which these roots stretch. This is a point in the anatomy of the nerve which has assumed greater importance since the discovery by Sir Charles Bell, of the separate functions of the anterior and posterior roots of the spinal nerves, and is of much more interest to the modern, than it was to the older anatomists. The filaments of origin or roots of this nerve that come from the spinal chord are attached to the chord near the posterior lateral groove separating its posterior and middle columns, and close upon the posterior roots of the spinal nerves, so that we can readily understand how some anatomists should describe these roots as arising from the middle column, and others describe them as springing from the posterior column.-j-Among the modern anatomists we find Bel-lingeri, who has attended particularly to the anatomy of this nerve, describing it as arising from the middle or lateral column of the\n* Huber (De Medulla Spinali, et speciatim de Nervis ab e\u00e2 provenientibus, p. 13.) says that this nerve commences opposite the seventh cervical, but he afterwards speaks of it arising opposite the sixth. Lobstein (De Nervo Spinali ad Par Yagum Ac-cessorio, p. 233, as reprinted in Ludwig\u2019s Script. Neurol. Min. Selec. tom. ii. Lipsi\u00e6, 1792) describes it as arising under the sixth pair of cervical nerves by a slender beginning. Bellingeri (De Medulla Spinali, Nervisque ex e\u00e2 prodeuntibus, p. 74, 1823) places its origin opposite the seventh cervical nerve. Cruveilhier (Anatomie Descriptive, tom. iv. p. 899, 1835) says that its origin seldom passes below the level of the fifth pair of cervical nerves, but it may arise opposite the sixth and even the seventh pair. Bendz (De Connexu inter Nervum Yagum et Ac-cessorium Willisii, p. 22, 1836) describes its lowest root as arising from the spinal chord in the region of the fifth or sixth cervical nerves, and rarely as low as the posterior root of the seventh cervical. Valentin (Soemmering vom Baue des menschlichen K\u00f6rpers. Hirn und Nervenlehre, S. 513, 1841) states that its most frequent origin is opposite the sixth, or between the sixth and seventh cervical nerves ; sometimes it arises opposite the fourth or fifth, or it may extend as far as the seventh, and in rare cases as far as the first dorsal. Krause (Handbuch der menchlichen Anatomie, Erster Band, S. 1066 : Hannover, 1842) says that it usually arises opposite the upper part of the roots of the seventh cervical, seldom higher. Bernard (Archives Generales de M\u00e9decine, 4i\u00e8me s\u00e9rie, tom. iv. p. 410, 1844) describes it as arising by a series of bifid or trifid nervous filaments, which extend, in man, from the origin of t he pneumogastric to a point opposite the fourth or fifth pair of cervical nerves.\nf Bolando (Recherches Anatomiques sur la Moelle Ablong\u00e9e) and Serres (Anatomie Compar\u00e9e du Cerveau, tom. i.) have stated that the lower fibres of tliis nerve come from the anterior column of the spinal chord.\nspinal chord*, while Bischofff and Bernard]; trace its origin to the posterior column ; and Bendz $ states that while nearly the whole of its roots come from the middle column, a few arise between the posterior roots of the spinal nerves and from the posterior column.|[ From my own examinations of the attachments of this nerve, I had arrived at the conclusion that it arises from the posterior part of the middle column, and that its middle and inferior roots are attached along the course of the decussating fibres of the pyramidal column, which form the posterior part of the middle column of the ehord.^f Stilling says** that the lower and middle roots of this nerve can be traced to the anterior grey substances in the chord, from which the anterior roots of the spinal nerves arise, and that, in an anatomical point of view, they must be regarded as performing the same functions as the anterior roots of the spinal nerves ; while the upper roots, or those which are attached to the medulla oblongata, differ in a marked manner, in regard to their origin, from the lower and middle roots. He states that these upper roots above the first cervical nerve arise from a grey mass in the medulla oblongata, which he styles the accessory-kernel (accessorius-kernf f ), and that they resemble closely the lower filaments of origin of the par vagum. These upper roots of the accessory do not arise from the gelatinous substance from which, according to Stilling, the posterior roots of the spinal nerves spring, yet they come into closer relation with it the nearer they approach to the commencement of the roots of the vagus. The upper fibres of the accessory, though not continuous with the posterior roots of the spinal nerves, are yet, he believes, analogous to these; and this view is strengthened by their presenting the same connection with the roots of the hypoglossal as is found between the roots of\n* De Medulla Spinali, Nervisque ex e\u00e2 prodeuntibus, pp. 51. 55, 1823.\nf Nervi Accessorii Willisii Anatomia et Physio-logia, p. 11. Darmstadii, 1832.\nX Archives G\u00e9n\u00e9rales de M\u00e9decine, 4i\u00e8me s\u00e9ri\u00e9, tom. iv. pp. 409, 410, 1844.\n\u00a7 Tractatus de Connexu inter Nervum Yagum et Accessorium Willisii, pp. 22. 39. Hauniae, 1836.\nIl Lobstein (De Nervo Spinali, in Ludwig\u2019s Scriptores Nevrologici Minores Selecti, torn. ii. p. 233.) also describes some of the filaments of origin of the spinal accessory as coming from the spinal chord between the fasciculi which constitute the posterior roots of the spinal nerves, and has represented these in fig. 1. Those who may wish to ascertain the opinions of other anatomists as to the particular column of the spinal chord into which this nerve is implanted, and the extent of its attachment to the cervical portion of the spinal chord, may consult the monographs of Bischoff and Bendz quoted above, and especially that of the former of these authors.\nOn some points in the anatomy of the medulla oblongata, in Edinburgh Medical and Surgical Journal for 1841.\n** Ueber die Textur und Function der Medulla Oblongata, pp. 55. 57. Erlangen, 1843.\nft He describes the position and structure of this accessorius-kern at p. 23. of the work quoted.","page":746},{"file":"p0747.txt","language":"en","ocr_en":"SPINAL ACCESSORY NERVE.\t747\nthe posterior and anterior spinal nerves at their origin.\nThe spinal accessory in its course within the spinal canal frequently forms communications with the posterior root of the first cervical, and much more seldom with the posterior root of the second cervical nerve.* * * \u00a7 When these communicating filaments come from the second cervical, they are generally few in number. This communication between the spinal accessory and the posterior root of the first cervical is, according to Lobstein, more frequently present than absent.f When the posterior root of the first cervical joins itself, either in whole or in part, to the spinal accessory, a branch of equal size generally leaves the accessory, either at the point where it is joined by the posterior root of the first cervical, as figured and described by Asch J, or a little above this junction, as figured by Huber^ and described by Bellingeri. |] This branch, after leaving the accessory, proceeds outwards, approaches the anterior root of the first cervical, and takes the place of the posterior root of that nerve.\u00ae!! When the posterior root comes from the accessory, it generally presents a ganglion in the usual position. Sometimes, however, though rarely, this ganglion is found on the accessory where the posterior root of the first cervical leaves it to join itself to the anterior root. This ganglion was first pointed out by Huber ; its existence has been denied by Lobstein, Asch, Haller, and Scarpa, and it has again been described by Bellingeri. I have seen this ganglion twice, and it was present on one side only. It becomes an interesting question in a physiological point of view to know, whether or not the whole of the filaments of the posterior roots of the spinal nerves which join themselves to the accessory, again leave it to form the posterior root of the first cervical. Bellingeri answers this question in the affirmative. \u201c The filaments,\u201d he says, \u201c coming from the posterior roots to the accessory are not intermixed, but only approximated, so that they can be separated by slight traction.\u201d**\n* Scarpa states (opus cit. p. 395.) that in a great number of bodies he examined with a special reference to this point, he found a communication between the accessory and the posterior root of the second cervical only in two instances.\nf Circa harum radicularum, qu\u00e6 pro radicibus posticis primi paris habenter, communicationem illud notamus, quod s\u00e6pius accessorium subire, quam eundem intactum relinquere observenter. Opus cit. p. 223.\nJ De Primo Pare Nervorum Medull\u00e6 Spinalis, tab. x. fig. 2. ; et explicatio, p. 335. Ludwig Scrip. Nevr. Min. Sei. tom. i.\n\u00a7 Opus cit.\n|| Opus cit. p. 80. Monro secundus has also given a representation of this communication between the accessory and posterior root of the first cervical. Observations on the Structure and Functions of the Nervous System, tab. x. fig. 2. 1783.\nBischoff states (opus cit. pp. 34. 82.) that in none of the numerous instances in which he dissected the accessory in the lower animals, did he ever observe any filaments of the posterior roots of the spinal nerves join themselves to it.\n** Opus cit. p. 81.\nAnd in another place he says, \u201c I believe that the filaments from the posterior roots, which join the accessory, leave it again to proceed to the posterior root of the first cervical.\u201d* From this he concludes that the accessory contains no sensiferous filaments. Miiller, on the other hand, has adduced some unusual anatomical arrangements in this nerve, which may be regarded as favouring the opinion that it contains sensiferous filaments independant of those which it may receive from the posterior roots of the spinal nerves. He mentions an instance f, which he elsewhere J describes at considerable length, where the posterior root of the first cervical nerve on the right side was not present, and where its place was supplied by two bundles of filaments from the superior part of the spinal accessory. The upper of these bundles, at least, came from the medulla oblongata. Upon the posterior root of the first cervical thus constituted, a ganglion was formed while it was still within the theca vertebralis. The upper fibres of the posterior root of the second cervical of this sidelined themselves to the accessory, but no nervous filaments were attached to the spinal chord in the usual position of the posterior root of the first cervical. On the left side, the posterior root of the first cervical presented its usual appearance, and was connected to the spinal accessory by some filaments of communication. The filaments of the accessory arising from the medulla oblongata did not, as on the right side, divide themselves into two parts, one of these becoming the substitute of the posterior root of the first cervical : but the whole ran upwards into the accessory nerve.|| Miiller also states that Hyrtl has often seen a ganglion upon the accessory nerve opposite the entrance of the vertebral artery into the interior of the cranium ; and that Remak showed him an instance of a ganglion upon the spinal accessory at its passage through the foramen lacerum. \u201c I do not, however, affirm,\u201d Miiller remarks in reasoning from these cases, \u201c that the spinal accessory always contains originally sensiferous filaments, but leave it doubtful.\u201d \u201c But in the case,\u201d he continues, \u201c where the nervus accessorius forms an intimate connection with the posterior root of the first cervical, or any other nerve, we may suppose an interchange; and this, in the same degree, will render probable the idea of Monro,\n* Ibid, p. 79.\nf Archiv, f\u00fcr Anat. und Physiol. 1834, p. 12.\nj Idem opus, 1837, pp. 279\u2014281.\n\u00a7 Arnold (Bemerkungen \u00fcber den Bau des Hirns und B\u00fcckenmarks, &c., S. 181\u2014183 ; Z\u00fcrich, 1838) has published remarks upon this anomalous instance in the origin of the posterior root of the first cervical from the accessory, the object of which is to endeavour to show that M\u00fcller had misinterpreted the facts observed. Among other things urged with this view, is the circumstance that the posterior root of the first cervical does not arise usually in the same line with the posterior roots of the other spinal nerves, but somewhat anterior to these. We cannot, however, believe that so experienced and accurate an anatomist as M\u00fcller is, could fall into any such mistake as is here insinuated.","page":747},{"file":"p0748.txt","language":"en","ocr_en":"748\nSPINAL ACCESSORY NERVE.\nthat the communication of the spinal accessory with the posterior root of the first, or with any other spinal nerve, will be an equivalent to it for a posterior root.\u201d We have already seen that Stilling concludes, on anatomical grounds, that those filaments of the accessory that come from the medulla oblongata contain centripetal filaments.*\nThe spinal accessory passes through the foramen lacerum posterius in a canal formed by the dura mater, common to it and the vagus, but they are occasionally separated from each other as they enter this canal by a bridle of arachnoid, or of the dura mater. Soemmering has pointed out that the accessory does not perforate the dura mater like the other nerves, but is, as it were, insensibly surrounded by this membrane.f\nOne or two filaments generally pass between the accessory and the superior ganglion oy ganglion jugulare of the vagus, as they lie in the foramen lacerum posterius. Hein states that he has more than once distinctly observed, as also Krause has remarked, the superior five, or even six filaments of the root of the accessory approximate very closely to the ganglion jugulare of the vagus, and partly enter into its formation, so that a junction between the vagus and accessory had already taken place in this ganglion, before the filaments of the accessory had been fully collected to form together the trunk of this nerve.J\nAs the spinal accessory is passing through the foramen lacerum, it is in close proximity to the posterior surface of the par vagum, and it there divides into its two branches\u2014its internal and external branches.\nThe former, or the internal, is composed of the filaments forming the upper roots of the nerve (flg. 521, 11.), and entirely, or almost entirely, of those coming from the medulla oblongata; and it joins itself to the vagus immediately below the ganglion jugulare of that nerve. The passage of the accessory through the foramen lacerum posterius, its division into two branches, and the distribution of the internal branch as far as it is known, have been already described in the art. Par Vaguai, vol. iii. pp. 883. and 890 , and need not be repeated here.\nThe external branch, composed of those fibres which arise from the spinal chord (y?g. 521,12.), proceeds downwards,outwards, and backwards behind the internal jugular vein, in front of the occipital artery, and behind the posterior belly of the digastric and stylo-hyoid muscle, and reaches the inner surface of the sterno-cleido-mastoid muscle at the lower part of its upper third. In con-\n* Stilling further states (p. 59) that in an anatomical point of view we may regard the upper roots of the accessory forming the internal branch of that nerve as being composed of centripetal and centrifugal filaments, exactly like the vagus.\nf \u201cNon reliquorum nervorum more, sub arcu dur\u00e6 membran\u00e6 fertur, sed insensili quasi modo a dura membrana obducitur.\u201d De Basi Encephali, &c., p. 104, reprinted in Ludwig\u2019s Scrip. Nevr. Min Sei., tom. ii.\nJ Muller\u2019s Archiv. 1844, p. 337.\ntinuing its course downwards and outwards, it here generally perforates the sterno-cleido-mastoid ; at other times it is only closely connected to it by cellular tissue ; but in both cases it gives branches to this muscle. In this part of its course it is strengthened and anastomoses with twigs of the third and second cervical nerves. Continuing its progress downwards and backwards it anastomoses with twigs of the fourth and fifth cervical nerves, and throws itself into the inner surface of the trapezius muscle, among whose fibres it is ultimately lost.\nComparative anatomy of the spinal accessory. \u2014 The origin and distribution of this nerve in the mammalia does not essentially differ from what is found in the human species.* Willis states that this nerve is not only present in the mammalia, but also in birds and fishes f ; but the existence of it in the two latter divisions of the vertebrata has been subsequently denied by many excellent anatomists. \u201c If an animal,\u201d says Mr. Shaw, \u201c does not perform part of the act of respiration by muscles which run from the skull to the chest, no spinal accessory is found. The truth of this observation may be shown by the dissection of any of the larger birds, but the most extraordinary proof is to be found in the neck of the camel. The constitution of the neck of this animal is like that of birds ; there being a succession of short muscles along the side of the neck, and attached to the vertebrae, but no long muscle passing from the jaw to the sternum to assist in breathing, as in other quadrupeds.\u201d J It appears, however, that in the camel this nerve is present, but it is smaller and differently distributed from what it is in the horse.\u00ff Serres found it in three of the larger birds, Weber in some fishes, and Bis-choff has given descriptions and representations of it in several birds, reptiles, and fishes. In these animals the upper part only of this nerve seems to be present, for it does not stretch downwards along the spinal chord to the same extent in them as in the mammalia. The whole of this nerve, in these animals, throws itself into the vagus, while a branch leaves the vagus after it has escaped from the cranium, and taking the place of the external branch of the accessory is distributed to the muscles of the neck in birds and in reptiles, and to the muscles which move the pectoral fin in fishes.|| In the chimpanzee, the spinal accessory, after passing through the foramen lacerum, divides into two branches. The internal runs towards the larynx, into which it penetrates above the os-hyoid. It is placed between the superior laryngeal nerve and stylo-hvoid ligament, and passes behind the internal carotid artery to the superior hyoi-\n* Dissections of this nerve upon several mammalia are given in detail by Biselioft' and Bendz.\nt Opus cit. p. 295.\nj London Medical and Physical Journal, vol. xlix. p. 458, 1823.\n\u00a7 Vide note by Dcfermon, at p. 527 of tom. ii. of the Archives G\u00e9n\u00e9rales de M\u00e9decine, 1823.\nIl A full account of the comparative anatomy of this nerve is given by Bischoff.","page":748},{"file":"p0749.txt","language":"en","ocr_en":"SPINAL ACCESSORY NERVE.\t749\nclean region (la region hyo\u00efdienne sup\u00e9rieure), where it terminates. The external branch passes downwards below the sterno-cleido-mastoid muscle to reach the trapezius, in which it is chiefly distributed.*\nFig. 521.\nFrom Bendz, reduced one-half.\nA, part of cerebellum cut across ; b, medulla oblongata; c, spinal chord ; a, floor of fourth ventricule ; b, calamus scriptorius ; cc, posterior. pyramidal bodies ; d, right restiforme body obliquely divided ; //, lateral columns of spinal chord; hh, posterior columns of spinal chord; i, posterior longitudinal fissure; kk, posterior roots of spinal nerves; 3 3, roots of vagus nerve ; 44, roots of glosso-pharyngeal ; 55 5, roots of nervus accessorius ; 6, ganglion of the root of the vagus or superior ganglion ; 7, auricular branch of vagus; 8, right ganglion petrosum of glosso-pharyngeal ; 9, ramus anastomicus of Jacobson ; 10, communicating branch between the superior ganglion of the vagus and the ganglion petrosum ; 11, roots of the accessory which form its internal branch; 12, roots of the accessory which form its external branch ; 13, glosso-pharyngeal nerve ; 14, trunk of the vagus ; 15, pharyngeal branch of vagus ; 16, filaments of this branch that come from the vagus ; 17, filaments of this branch that come from the internal branch of the accessory; 18, ganglion of the trunk of the vagus or inferior ganglion; 19, nervus laryngeus superior; 22 22, communicating branches between the ganglion of the trunk of the vagus and the superior ganglion of the sympathetic; 23, fibres of the internal branch of the accessory which do not enter into the formation of the ganglion of the trunk of the vagus ; 24, branch from these fibres which joins itself to the external branch of the superior laryngeal nerve.\nPhysiology of the accessory.\u2014 The peculiar origin and course of this nerve, and particularly its intimate connection with the par vagum, have formed the basis of most of the speculations on its functions since the time of Willis. It was maintained by Willis that this nerve, from its connection with the par vagum, regulates those involuntary movements of the neck and arm caused by the emotions and\n* Eecherches d\u2019Anatomie Compar\u00e9e sur le Chim-\npans\u00e9 : par W. Vrolik, p. 40. Amsterdam, 1841.\npassions.* Lobstein likewise believed that the spinal accessory joins the vagus for the purpose of connecting itself with the involuntary functions, and he supposed that its paralysis might also affect the movements of the pharynx and larynx.f Others have maintained that it is a nerve of involuntary motion from the particular portion of the spinal chord in which it is implanted. It is, as is well known, one of Sir Charles Bell\u2019s respiratory nerves, arising as he supposed from a particular tract in the spinal chord to which he gave the name of respiratory tract, and is therefore, according to this view, a nerve of involuntary motion. Bedingen believes that the lateral tract of the spinal chord, from which the accessory arises, presides over the instinctive and sympathetic movements, and that it is consequently a nerve of involuntary motion. J Arnold $, Scarpa ||, Bischoff'^, Valentin **, and Longet -ff, have maintained that the accessory stands in the same relation to the vagus as the anterior roots of the spinal nerves do to the posterior roots.JJ According to this last view, the vagus does not originally possess any motor filaments, but derives them from the spinal accessory. The two first of these authors came to this conclusion on anatomical grounds alone ; the three latter, from experiments upon these nerves in living animals, as well as from their anatomy. Bernard has arrived at the conclusion that it is entirely a motor nerve, and that it enables the larynx and pharynx, and muscles of the neck in which it is distributed, to partake in the production of the phenomena of phonation, but that it does not assist in any of the true respiratory movements.\u00ff\u00ff Dr. Todd and Mr. Bowman ||||, on the other hand, believe that the internal branch of the accessory is composed of afferent nerves, and that the mode of implantation of this nerve in the central organs of the nervous system serves to bring the sentient surface of the lungs and air-passages into immediate relations with the roots of all those nerves which animate the great muscles of respiration, the phrenic, the external thoracic, the cervical plexus, and the motor fibres of the spinal accessory and vagus nerves.\nAll experimenters agree that the external\n* Opus cit. caput xxviii.\nf Ibid. pp. 345, 346.\nJ Ibid. pp. 89, 90.\n\u00a7 Oer Kopftheil des vegativen Nervensystems. Heidelberg, 1831.\nII De Gangliis Nerv, deque Essentia Nervi Intercost. Ann. Univers, di Medicina, 1831.\nT Nervi Accessorii Willisii Anatomia et Phy-siologia, 1832.\n** De Functionibus Nervorum Cerebralium et Nervi Sympathici, 1839.\nff Anatomie et Physiologie du Syst\u00e8me Nerveux, &c., torn, ii., 1842.\nJJ It appears that this idea had been previously suggested by G\u00f6rres (Exposition der Physiologie, Coblentz, 1805, as quoted by M\u00fcller).\n\u00a7\u00a7 Archives Generales de M\u00e9decine, 4i\u00e8me s\u00e9ri\u00e9, tom. iv. and tom. v., 1844.\nIl II The Physiological Anatomy and Physiology of Man, vol. ii. p. 130.","page":749},{"file":"p0750.txt","language":"en","ocr_en":"750\nSPINAL NERVES.\nbranch of the spinal accessory is a motor nerve. We found that when it was embraced firmly within the forceps, or tied tightly soon after it had emerged from the foramen lacerum, the animal gave indications of suffering* * * \u00a7 ; but an experiment of this kind does not enable us to decide whether these sensiferous filaments were originally contained in the accessory, or were derived from the neighbouring nerves. Mr. Shaw has detailed an experiment to show that the movements which it imparts to the sterno-mastoid, and to the trapezius are not voluntary, but respiratory.j In our experiments, and in those subsequently performed by Bernard, these muscles acted in unison with the muscles of respiration after the spinal accessory nerves had been divided.\nWhile all experimenters agree that the external branch of the accessory is chiefly if not entirely composed of motor filaments, they have arrived at discrepant conclusions regarding the functions of the internal branch. Volkmann J, Van Kempen $, and Stilling |j, observed no movements of the muscles in which the internal branch of the accessory is distributed, on irritating the roots of this nerve within the cranium ; while in those of Bischoff, my own, those of Valentin^, Longet** * * \u00a7\u00a7, Hein-j-j', Morganti|J, and Bernard \u00a7\u00a7, partly consisting of irritating the roots of the nerve within the cranium after death, and partly, as in those of Bischoff', Longet, Mor-ganti, and Bernard, by lesions of the nerve in living animals, and observing their effects upon the movements of the muscles in which it is distributed, proofs of its being a motor nerve were believed to be obtained. We think that this evidence is sufficiently strong to justify the belief that the internal branch of the accessory does contain motor filaments;\n* Edinburgh. Medical and Surgical Journal for January, 1838. Valentin states (opus cit. pp. 58. 62.) that he succeeded in increasing the action of the heart by irritating the trunk of the accessory ; but Van Kempen (opus cit. p. 65) repeated this experiment without success.\nf London Medical and Physical Joumal, vol. xlix.\nJ M\u00fcller\u2019s Archiv. 1840.\n\u00a7 Essai Experimental sur la Nature Fonctionelle du Nerf Pneumogastrique : Louvain, 1842. In giving the results of Van Kempen\u2019s experiments in the art. ParVagum, foot-note at p. 891, vol. iii. upon the effects of irritating the roots of the vagus within the cranium, T have inadvertently written the pa-lato-glossus muscle instead o/the palato-pharyngeus or pharyngo-staphylin muscle, as one of the muscles seen to contract in this experiment. I may also here correct another error in the same article : at p. 900, it is stated that Longet believes that the secretion of the gastric juice is greater after section of the vagi than in the sound animal ; while in fact he states that it is diminished by section of the vagi, and that this diminution in the secretion may be explained on mechanical grounds.\n|| Bischoff\u2019s Bericht \u00fcber die Fortschritte der Physiologie im Jahre 1842, S. 154. In M\u00fcller\u2019s Archiv. 1843.\nOpus supra cit.\n** Opus supra cit.\nff M\u00fcller\u2019s Archiv. 1844.\n+j Omodei, Annali Universali di Medicina. Juli, 1843.\n\u00a7\u00a7 Opus supra cit.\nbat it is at the same time highly probable that it is partly composed of sensiferous and afferent filaments, and if so, its constitution must be similar to the vagus nerve, with which it becomes so closely incorporated. In the art. Par Vagum, sufficient proof has been adduced to satisfy us that the opinion that the spinal accessory furnishes all the motor filaments contained in the trunk of the vagus, is no longer tenable.\n(John Reid.)\nSPINAL NERVES (Les Nerfs rachidiens, Fr. ; Die Rueckenmarksnerven, Germ. ; I Nervi Spinali, Ital.) are thirty-one pairs, and are distributed to the neck, and the upper extremities, the trunk and lower extremities. They are divided into Cervical, Dorsal, Lumbar and Sacral : the first division comprising eight ; the second, twelve ; the third, five ; and the fourth, six. Their general and special characters, and their apparent and absolute connexion with the spinal chord having been already described *, we shall limit the details of this article to their ultimate distribution.\nEach spinal nerve, after the union of its roots, divides into an anterior and posterior branch, the former having generally a much more complicated and extensive distribution than the latter. It will be convenient therefore for the purpose of description to enter first into a consideration of the posterior branches.\nThe posterior branch of the first cervical or sub-occipital nerve is larger than the anterior, and passes internal to and below the vertebral artery, between the arch of the atlas and the occipital bone, to gain the triangular space between the rectus capitis posticus major, the superior and inferior oblique muscles. It is here imbedded in a considerable quantity of fat and dense cellular membrane, and having directed itself from before,backwards, and slightly from belowupwards,dividesinto a series of branches. Two external branches are sent to the two oblique muscles : an internal ascends to the rectus capitis posticus major, and which having supplied this, terminates in the minor : another filament is directed to the anterior aspect of the complexus near to its occipital attachment: and the terminal branch descends, generally perforating the inferior obliquely, and anastomoses with the posterior branch of the second cervical nerve.\nThe posterior branch of the second cervical nerve emerges from between the lower border of the posterior arch of the atlas, and the lamina of the axis, and is larger than any of the posterior branches of the cervical nerves, and three or four times greater than the anterior branch of the same nerve. It appears at the lower border of the inferior oblique, and having passed a short distance horizontally inwards, winds round this muscle to the anterior aspect of the outer part of the complexus, which it perforates. It inclines outward and upwards between it and the\n\u2666 Vide Nervous System, vol. iii. p. 657.","page":750},{"file":"p0751.txt","language":"en","ocr_en":"SPINAL NERVES.\ntrapezius, passes through the latter, and terminates in the skin in the occipital region as the great occipital nerve, coursing along with the occipital artery but lying internal to it. Before becoming great occipital, it gives off at the lower border of the inferior oblique a branch to supply this muscle and a superior and inferior anastomotic branch to communicate with the first and third cervical. When passing along the anterior surface of the corn-plexus, numerous branches are given off to this muscle, the trapezius, and splenius. Those for the last muscle are more numerous and larger than the branches, for the two others are directed to the anterior aspect of the muscle, and one or more of them perforate the com plexus before reaching it.\nThe posterior branch of the third cervical is smaller than the second, but larger than the fourth, and situated more externally, emerging from between the transverse processes of the second and third cerv'cal vertebra. It is directed inwards, between the opposed surfaces of the complexus and semispinalis colli towards the median line, and having reached the sides of the spinous processes of the vertebrae, divides into ascending and horizontal cutaneous branches. The ascending branch, after a short course, perforates the inner border of the complexus and trapezius, and becomes cutaneous. It continues its course close to the median line, as far as the region of the occiput, the inner and lower part of which it supplies on the internal side of the great occipital nerve.\nThe horizontal branch passes between the ligamentum nuchae and the inner border of the complexus, and after having perforated the tendon of the trapezius, terminates in external small cutaneous filaments. The nerve prior to division, and at the outer border of the semispinalis colli, communicates by one or more filaments with the posterior branch of the second cervical. From the anastomosis between the communicating branches of the posterior roots of the three first cervical nerves, results an irregular plexus placed between the complexus and outer part of the semispinalis colli, and consequently nearly in a line with the transverse processes of the superior cervical vertebras. From this posterior cervical plexus, numerous branches arise to supply the complexus, splenius, and semispinalis colli. The anastomosis between these posterior branches is, according to Cruveilhier, sometimes deficient.\nThe posterior root of the fourth cervical nerve varies much as to individual size, but is always smaller than the preceding. It passes downwards and inwards between the complexus and semispinalis colli, and having reached the side of the median line, perforates the tendons of the splenius and trapezius, and becomes cutaneous. In its course it supplies these muscles, and occasionally terminates in the splenius without going to the skin.\nThe posterior branches of the fifth, sixth, seventh, and eighth cervical nerves have a similar course to the fourth, but decrease in\n751\nsize from above downwards. The fifth and sixth usually pass between the opposed surfaces of the semispinalis colli and complexus, give branches to these muscles, and perforate the inner part of the tendons of the splenius and trapezius, to terminate in the skin at the lower part \u00f4f the nape of the neck.\nThe posterior branches of the seventh and eighth cervical nerves pass either through the deep-seated fibres of the semispinalis colli, or between it and the multifidus spinas, give branches to these two muscles, perforate the tendons of the trapezius and splenius, and terminate by ramifying, the one on the skin above the scapula, the other over the integument, as far as about the spinous process of the third dorsal vertebra. The inter-trans-versaies muscles, cervicalis ascendens, tra-chelo-mastoid, and transversalis colli, receive numerous small filaments from these nerves almost immediately after their appearance in the neck.\nThe posterior branches of the dorsal (thoracic) nerves are much smaller than the anterior, and are directed backwards between the ascending costo-transverse ligaments and the sides of the vertebrae. Having reached the outer border of the semispinalis dor,si and multifidus spinae, they divide into external and internal branches, the latter being muscular and cutaneous in their distribution, the former only muscular in the eight upper. In the first eight the internal branches are larger, in the last four much smaller than the external.\nThe external or muscular branches of the eight superior pass between the sacro-lum-balis and longissimus dorsi, and give off numerous filaments to supply these muscles, and the levatores costarum ; that of the first sending a few filaments to the cervicalis ascendens, trachelo-mastoid, transversalis colli, and sca-leni muscles.\nThe internal branches wind either over the posterior aspect of the semispinalis dorsi, or between it and the multifidus spin\u00e6, and having supplied these muscles with numerous filaments, reach the sides of the spinous processes ; here they perforate the rhomboid, latissimus dorsi, and trapezius, the last muscle very obliquely, and become cutaneous, being principally distributed to the skin at the back part of the scapular region.\nThe external branches of the four inferior pass obliquely downwards and outwards between the sacro-lumbalis and longissimus dorsi, communicating with each other in their course, and at the outer border of the former muscle perforate the tendon of the latissimus dorsi, and become cutaneous, some of the lower filaments being capable of being traced over the glut\u00e6al region.\nThe internal branches of the four inferior are remarkably small, and are lost either in the substance of the multifidus spin\u00e6, or semispinalis dorsi. The cutaneous filaments from the posterior branches of the dorsal nerves given off on the one hand from the internal, and on the other from their external divisions*","page":751},{"file":"p0752.txt","language":"en","ocr_en":"752\tSPINAL\nare situated somewhat in a line with the angles of the ribs, so that they become more external in proportion to their inferior position.\nThe posterior branches of the lumbar nerves are analogous in their distribution to the four lower dorsal branches, having an external large musculo-cutaneous, and small internal muscular divisions. The external branches run along the deep surface of the longissimus dorsi, and at its outer edge perforate the tendon of the latissimus dorsi, and terminate in cutaneous filaments directed over the crest of the ileum to the glut\u00e6al region, as far as on a level with the great trochanter. The internal branches are lost in the substance of the multifidus spin\u00e6.\nThe posterior branches of the sacral nerves exist as distinct branches within the spinal canal, and consequently differ from the cervical, dorsal, and lumbar, which become distinct trunks after the main trunks have issued from the spinal or intervertebral foramina. They decrease in size from above downwards, being extremely small, and passing out of the posterior sacral foramina, the fifth coming out between the sacrum and coccyx. They form a minute anastomosis with each other, and with the corresponding branch of the last lumbar, and after having given filaments to the lower part of the erector spin\u00e6, perforate the tendon of that muscle, and are distributed to the skin over the sacrum and coccyx, and immediately around the anus.\nThe anterior branches of the spinal nerves are much larger than the posterior branches, the two upper cervical forming the only exception. They form intricate plexuses in the neck, the lower part of the spine and sacrum, the nerves given off from those in the first situation being principally intended for the neck and upper extremities ; in the two last for the lower extremities. The intervening series represented by the thoracic nerves, being comparatively simple in their distribution, do not form plexuses.\nThe Anterior Branches of the Cervical Nerves.\nThe anterior branch of the first cervical nerve, smaller than the posterior, is directed between the occipital bone and the transverse process of the atlas, passes over the outer edge of the vertebral artery, and appears at the inner side of the rectus capitis lateralis. It then descends, and forms an anastomotic arch with the anterior branch of the second, in front of the transverse process. In its course the rectus capitis lateralis, and rectus capitis anticus minor receive one or more filaments, and it also sends a filament into the canal for the vertebral artery, and which communicates with the trunk of the second cervical between the transverse processes of the atlas and axis. From this anastomotic arch are given off filaments which communicate with the lingual and par vagum and superior cervical ganglion of the sympathetic.\nThe anterior branch of the second cervical\nNERVES.\nnerve, also much smaller than the posterior passes forwards between the transverse processes of the atlas and the axis, being concealed by the levator anguli scapulae, splenius, and first inter-transverse muscle, and divides into an ascending branch, passing in front of the transverse process of the atlas, to communicate with the first cervical ; and a descending branch.\nThe descending branch soon subdivides, and gives several filaments of communication with the superior cervical ganglion ; one small filament to communicate with the par vagum, another enters the rectus capitis anticus major, and the last concurs to form the cervical plexus.\nAnterior branch of the third cervical nerve, larger than the posterior, and twice as large as the preceding, passes between the vertebral artery and inter-transverse muscles, and having given branches to the levator anguh scapulae and rectus capitis anticus major, communicates above with the descending branch of the second, below with that of the fourth, and in the interval with the superior cervical ganglion, and then again bifurcates to enter into the formation of the cervical plexus.\nThe anterior branch of the fourth cervical nerve, of the same size as the preceding, communicates above with the third, below with the fifth cervical, in the middle with the superior cervical ganglion, and then enters into the formation of the lower part of the cervical plexus.\nThe cervical plexus (the deep cervical plexus) is composed of the primary and secondary anastomosing arches of the anterior branches of the four upper cervical nerves. These anastomosing arches are subject to considerable variation, though generally formed by each nerve bifurcating, and, after having communicated with the nerve above and below, again reuniting in a more or less uniform manner prior \\ to giving off their terminal branches. The plexus is situated deeply at the upper anterior and outer part of the neck behind the posterior edge of the sterno-mastoid, in front of the scalenus posticus, external to the rectus capitis anticus major, the carotid artery, jugular vein, and par vagum. It constitutes the chief contents of the posterior superior cervical triangle, and is surrounded by a large quantity of loose cellular membrane, absorbent glands, and fat, and immediately invested with a prolongation of the deep cervical fascia, which renders the dissection of the numerous branches as they immediately proceed from it, difficult. It communicates internally by several delicate filaments with the superior and middle cervical ganglia of the sympathetic; below with the upper part of the brachial plexus, and externally with the spinal accessory, giving several filaments to the muscles with which it is in immediate relation. The branches given off from the cervical plexus may be divided as follows, into\nI Superficialis colli. Auricularis magnus. Occipitalis minor.","page":752},{"file":"p0753.txt","language":"en","ocr_en":"SPINAL NERVES.\n7\u00d63\nSuperficial descending\nDeep\nSupra-clavicular. Supra-acromial. Communicating branches. Muscular.\n[ Phrenic.\nThe superficialis colli (superficial cervical nerve) takes its origin from the middle of the plexus in company with, but anterior to the great auricular, the anastomosing branches of the second and third cervical nerves concurring to form it. It emerges from behind the posterior border of the sterno-mastoid about the middle of the neck, and is directed horizontally forwards and inwards, behind the external jugular vein, and between the sterno-mastoid and platysma, and at a variable point divides into two branches, an ascending and descending, the former larger than the latter.\nThe ascending branch almost immediately divides into numerous filaments, some of which supply the platysma myoides ; one or two ascending along the external jugular vein. The greater number are directed upwards and forwards to the upper part of the platysma and digastric muscle, communicate with the deeper seated filaments given off' from the portio dura, and becoming cutaneous, supply the skin over the region of the sub-maxillary gland, the chin (communicating with the sub-mental nerve), and the lower part of the cheek ; some filaments being directed to the median line to communicate with the corresponding nerve of the opposite side.\nThe descending branch forms a loop, the concavity of which looks upwards ami inwards, perforates the anterior part of the platysma, a little above the middle of the neck, gives off one or two twigs to accompany the anterior jugular vein, and terminates in the skin about the hyoid bone.\nThe auricularis magnus (the auricular nerve) arises in common with the trunk of the superficial cervical from the anastomosing branches between the second and third cervical. It emerges from behind the posterior border of the sterno-mastoid, above the superficial cervical, and in front of the occipitalis minor. It winds round the edge of the sterno-mastoid, and is directed along it obliquely upwards and inwards to the lower part of the parotid gland on a level with the angle of the jaw, reaches to the anterior border of this muscle, and divides into a superficial and deep terminal branch. It gives off\" before dividing several filaments between the parotid gland and the skin, and others which pass through the substance of the former to terminate in the skin in the malar region, where it communicates with the facial nerve.\nThe superficial branch courses upwards in the parotid fascia, and on a level with the antitragus divides into several filaments, which are distributed on the one hand to the con cave surface of the auricle, particularly the concha ; and on the other, to the anterior border of the helix, and the vertical groove in front of it.\nThe deep branch (anterior mastoid), having\nperforated the parotid gland, and crossed the auricular branch of the facial, with which it communicates, becomes placed behind the auricle of the ear, ascends along the anterior part of the mastoid process, communicates with the occipitalis minor, and terminates by supplying the skin at the back of the ear, some filaments passing on to its upper border.\nThe occipitalis minor (mastoid, external occipital) comes from the posterior part of the cervical plexus, taking its origin from the second cervical. It appears at the posterior edge of the sterno-mastoid, behind and above the great auricular. It passes upwards parallel with the great occipital nerve directed by the border of the splenius, which it occasionally perforates, to the occipital region behind the mastoid process ; communicates with the great auricular externally, and with the great occipital nerve internally, and ends by terminating in the skin over the parietal bone. There occasionally occurs a small accessory nerve, between the auricularis magnus and occipitalis minor. This is directed along the posterior border of the sterno-mastoid, and is distributed to the skin over the mastoid process.\nThe supra-clavicular and aci'omial nerves, form the termination of the cervical plexus, and exist as two primary trunks, which usually about the level of the posterior belly of the omo-hyoid, divide and subdivide into numerous branches, which traverse superficially the posterior inferior triangle of the neck, first passing behind the platysma, then between it and the skin, The internal series (sternal) are directed forwards and inwards, over the lower part of the sterno-mastoid, the inner third of the clavicle, and end in the skin over the upper part of the sternum, and upper and inner part of the pec-toralis major. The middle filaments (mam-mary'), pass over the centre of the clavicle, and are distributed to the skin of the pectoralis major and the mammary gland, and communicate with branches of the intercostal nerves. The posterior (clavicular) pass downwards and outwards over the outer third of the clavicle, and ramify in this skin over the anterior and outer part of the deltoid.\nThe acromial nerves are larger than the clavicular, and are, ordinarily, two in number. They pass obliquely outwards, downwards, and backwards, over the lower part of the superficial aspect of the trapezius, give some filaments to this muscle, which communicate with the spinal accessory nerve, and having reached the acromion, divide into numerous cutaneous branches, which are lost in the skin covering the spine of the scapula, and the outer and back part of the deltoid.\nThe communicating branches have been already partly described in the consideration of the formation of the plexus ; and are formed by different filaments, which are connected with the trunk of the sympathetic, its upper and middle cervical ganglion, as also with the par vagum and lingual. The internal deep branch is represented by the comnninicans noni or internal descending cervical. It takes\n3 c","page":753},{"file":"p0754.txt","language":"en","ocr_en":"754,\nSPINAL NERVES.\nits origin principally from the descending division of the second cervical, and having received a filament from the first cervical, comes down the neck external and posterior to the internal jugular vein. At the middle or lower third of the neck, it describes a curve ; the concavity of which looks upwards, and communicates with the descending branch of the lingual (descendens noni), by winding in front of the internal jugular vein. This nerve is subject to considerable variation, bifurcating, occasionally, before communicating with the descendens noni, and giving off now and then one or two delicate filaments to the same muscles, usually supplied by the latter nerve : viz. the sterno-hyoid, sterno-thyroid, and omo-hyoid. The external communicating branches are represented by a rather larger anastomotic branch, which communicates at an acute angle with the spinal accessory ; and by the muscular branches. These accompany the spinal accessory, communicate more or less with it, and are distributed to the trapezius, levator anguli scapulae, the rhomboideus minor, and upper part of the rhomboideus major.\nThe phrenic nerve (diaphragmatic, internal respiratory) appears at the lower and anterior part of the fourth cervical nerve of which it appears the continuation. It receives, however, some accessory filaments from the third and fifth cervical, which exist either as single or plexiform twigs, or are occasionally absent. The secondary sources of origin are, in fact, subject to considerable variation. It is directed along the anterior edge of the scalenus anticus, inclining slightly inwards between the subclavian artery and vein, before entering the superior opening of the thorax. It passes behind and outside the carotid artery and jugular vein, and communicates with the fifth, sixth, and, occasionally, with the seventh cervical and pneumogastric nerves, and invariably with the sympathetic. The exact points of communication of these different nerves is by no means determinate ; sometimes taking place in the neck ; at others, in the upper part of the chest. It crosses the direction of the internal mammary artery, and reaching the anterior mediastinum, glides down in front of the root of the lung between the pericardium and inner aspect of the former, and terminates in the diaphragm. In its course within the chest, it gives several filaments to the remains of the thymus gland ; some very minute twigs of communication with the superior cardiac plexus ; and receives, occasionally, a very delicate filament of communication, coming down obliquely, from the descendens noni : on reaching the diaphragm, the nerve divides into a series of superior and inferior filaments ; the former, long and diverging from each other, enter the upper surface of the muscle, having first passed for some distance between the muscle and the pleura covering it; the latter perforate the muscle, diverge, and run for some distance between the muscle and peritoneum, and enter its under surface.\nThe right phrenic is shorter and more ver-\ntical in direction, and more anterior in its position than the left, being directed in the upper part of the chest, along the vena cava superior. Several of its internal terminal filaments pass behind the vena cava inferior, communicate with the left, and end in the cceliac plexus ; a few, however, communicate, also, with some twigs of the pneumogastric.\nThe left phrenic turns over the apex of the heart; and, besides its general distribution, gives filaments to the crura of the diaphragm, anastomosing filaments to the solar and cceliac plexus, and some communicating branches to the opposite nerve.\nThe anterior branches of the four inferior cervical and first dorsal nerves are very large, and form, therefore, a remarkable contrast to the four upper cervical, situated above them. They pass through the intervertebral foramina, between the two scaleni ; the eighth cervical passing between the foramen common to the last cervical and first dorsal vertebra. Having given off several filaments to communicate with similar filaments from the inferior and middle cervical ganglion, and some small twigs to the scaleni, the different branches unite together, so as to constitute the brachial plexus; the first, communicating above with the fourth cervical, and sending a twig to the phrenic. The union of the different branches takes place in the following manner : \u2014 the anterior branches of the fifth and sixth descend obliquely outwards, and, after a course of about one or two inches, unite at an acute angle. Those of the eighth cervical and first dorsal, which are not so oblique in their direction, similarly unite; but a little more internally : this union taking place, occasionally, between the scaleni, either pair of branches almost immediately bifurcating after their union. The trunk of the seventh passes distinct between the two upper and lower branches, as far as the lower border of the clavicle in the upper part of the axilla, and there bifurcates ; the upper part of the bifurcation being connected with the lower part of the bifurcation of the first united cord, and the lower with the upper of the last united cord. Secondary bifurcations and anastomoses take place at more or less acute angles, and thus the brachial plexus is constituted.\nThe brachial plexus (axillary) is situated at the inferior and lateral part of the neck, in the posterior inferior cervical triangle, where it is covered in by a considerable quantity of fat, cellular membrane,and lymphatic glands, which separate it from the external jugular vein. The scalenus anticus bounds it in front and internally ; the scalenus posticus in the opposite direction ; and in its course from between these muscles to the clavicle, it is crossed by the omo-hyoid muscle, transversalis coli, and humeral vessels, and more superficially, by the supra-clavicular and acromial branches of the cervical plexus. Having passed from beneath the clavicle, it becomes placed between the coracoid process of the scapula and the first digitation of the serratus magnus,","page":754},{"file":"p0755.txt","language":"en","ocr_en":"SPINAL NEUVES.\nand anterior and external to the first rib, and there divides into its terminal branches. In the neck, the plexus is situated superior, posterior, and external to the artery ; but as the trunks gradually converge towards the axilla, and the terminal branches again diverge, the artery comes to be bounded by some internally, by others externally. The plexus is broad above, where it represents the base of a triangle, and narrow below at its termination at the upper part of the axilla.\nThe different branches of the plexus may be divided into those given off above, and those below the clavicle : \u2014 the former, for the levator anguli scapula, subclavius, rhomboid, and serratus magnus; the latter, for the upper extremity and its muscles.\n\u201d Muscular, supra-scapular.\nSubscapular.\n' Internal cutaneous. External cutaneous. Median.\nUlnar.\nSupra-clavicular -\nInfra-clavicular\nMusculo-spiral.\n_ Circumflex.\nOf the muscular branches. The nerve for the rhomboideus takes its origin from the anterior branch of the fifth cervical, immediately after it has quitted the intervertebral foramen ; but is frequently given off from the cervical plexus : it is, consequently, deeply seated. It either perforates the scalenus porticus or winds round it, to get between it and the levator anguli scapulae ; continues along the costal surface of the latter muscle, and then passes to the same surface of the rhomboideus, as far as its lower part, frequently supplying, in its course, the levator anguli scapulae, which, in many cases, however, receives filaments from a distinct nerve arising above it, and taking a similar course.\nThe nerve to the serratus magnus (external respiratory, posterior thoracic), situate at the posterior and upper part of the plexus, arises from it by two delicate roots, which come off from the lower edge of the fifth and sixth cervical, immediately after they have passed the intervertebral foramina. It receives, sometimes, a twig from the seventh. It is directed downwards and outwards, and reaches the thorax between the subscapularis and serratus magnus, passing behind the axillary vessels. It passes along this muscle inferior, to the long thoracic artery, and terminates in its lower part, by numerous filaments.\nThe nerve for the subclavius is very small, but always present, and is given off from the anterior part of the united trunk of the fifth and sixth cervical. It passes down anterior to the subclavian artery, and enters the middle of the muscle.\nThe remainder of the muscular branches are very small, and come off from the lower and anterior part of the plexus, being principally derived from the seventh cervical : some pass behind, and others, in front of the axillary artery, enter the axilla, and are distributed to the posterior surfaces of the pecto-ralis major and minor. They are known\nunder the collective name of anterior or short thoracic.\nThe supra-scapular nerve, larger than the long thoracic, issues from the upper and back part of the plexus, from the united root of the fifth and sixth cervical at their angle of union. It is directed downwards, outwards, and backwards in company with the suprascapular vessels, passes behind the trapezius and coracoid process to the notch in the upper edge of the scapula, beneath the ligament which converts this notch into a foramen, and which separates it from the supra-scapular vessels. Having reached the supra-spinal fossa, and supplied the supra-spinatus muscle, it winds along the concave external border of the spine, and reaches the infra-spinal fossa, supplying the infra-spinatus. From the inferior filaments one or two twigs can be traced to the teres minor.\nThe subscapular nerves are intended for the latissimus dorsi, teres major, and subscapularis. That for the first muscle is the largest and longest. It arises from the plexus above, and internal to the circumflex nerve, passes down in the axilla between the subscapularis and serratus magnus, parallel, but posterior to the long thoracic, and terminates by reaching the lower border of the latissimus dorsi, where it enters its substance. It gives off\u2019 occasionally in its course the branch from the teres major, v^hich usually, however, arises from the plexus below it. This nerve passes downwards and outwards at the subscapularis, and enters the anterior surface of the teres major.\nThe nerves for the subscapularis are : a small one, generally constant as to its origin arising high up from the same source of origin as the circumflex, passing behind the axillary-artery to the upper part of the superficial surface of the subscapuhu\u00fbs ; the other larger, and frequently derived from the circumflex, to be distributed to the middle of the muscle.\nThe internal cutaneous, the smallest of the terminal branches of the brachial plexus, and situated most internally, takes its origin principally from the last cervical and first dorsal. It descends, covered in by the brachial aponeurosis, along the inner aspect of the arm, between the median and the ulnar, and concealed above by the axillary artery. Deeply seated in the axilla, in leaving this cavity it inclines slightly forwards and outwards in company with, but anterior to, the basilic vein ; and at a variable distance from the elbow joint, generally a little below the middle of the arm, divides into external and internal cutaneous branches : both of which perforate the fascia. In this part of its course the internal cutaneous gives off in the axilla a small cutaneous filament, which, having communicated with the second or third intercostal nerve, perforates the fascia, and supplies the skin on the inner part of the arm as far as the internal condyle.\nThe external terminal branch, the continuation of the trunk in the arm, and the larger of the two, divides into two or three twigs, which pass either in front or behind the\n3 c 2","page":755},{"file":"p0756.txt","language":"en","ocr_en":"SPINAL NERVES.\nmedian basilic vein, some occasionally passing in front, and some behind. The external filaments course down the anterior and inner part of the fore-arm, following the direction of the median vein, and communicating with branches of the external cutaneous : the internal follows the course of the ulnar vein, communicating with a twig of the ulnar nerve at the lower part of the fore-arm. Both terminate in the integument over the annular ligament.\nThe internal branch, frequently perforating the fascia lower down than the external, passes behind and then below the median basilic vein, to the inner and back part of the fore-arm, and having communicated a little below the elbow with the accessory internal cutaneous, continues its course, and supplies the integument along the inner and back part of the fore-arm as far as the inner edge of the hand, communicating, in its course, with the innermost filaments of the external branch.\nPlaced behind and internal to the internal cutaneous nerve, is the cutaneous nerve of Wrisberg (the accessory nerve of the internal cutaneous), considerably smaller than it. It arises from the united chord formed by the seventh cervical and first dorsal. It descends along the inner part of the axilla, and communicates with the cutaneous branch of the second intercostal. Coursing down the arm on a plane behind the ulnar and internal to the basilic vein, it perforates the fascia about the lower third, and, becoming cutaneous, divides into anterior filaments, communicating with the internal cutaneous : and posterior, communicating with the internal cutaneous brandi of the musculo-spiral.\nThe external cutaneous (musculo-cuta-neous : perforans casserii), larger than the preceding, but smaller than all the other nerves, and most external, is formed by the fifth and sixth cervical. It is directed obliquely downwards and outwards in front of the tendon of the subscapularis to the inner aspect of the coraco-brachialis, perforates this muscle (occasionally, however, passes behind it without perforating), and then becomes situated obliquely between the biceps and bra-chialis anticus. At a short distance from the elbow' it emerges from beneath the outer border of the biceps, and internal to the supinator longus ; and at the bend of the elbow, after passing behind the median cephalic vein, bcomes subcutaneous. In this part of its course the external cutaneous nerve gives off a series of muscular branches. Of the two branches to the coraco-brachialis, the upper, having perforated it, terminates in the short head of the biceps.\nThe branches to the biceps unite separately or by a common trunk, and one of them perforates the biceps, and supplies the elbow-joint, being here situated to the outside of the superficial flexor tendons.\nThe branches for the brachialis anticus are several, and penetrate the muscle by its superficial surface. The continuation of the external cutaneous nerve in the fore-arm is represented\nby a series of internal and external cutaneous branches, which pass down along either side of the radial vein. The former near the wrist joins with a branch from the radial nerve, and gives off a filament which perforates the fascia, and accompanies the radial artery to the outer and back part of the wrist, where it supplies small twigs to the front and back of the radioulnar articulation. The latter gives filaments to the outer and back part of the fore arm, as far as the wrist.\nThe median nerve. \u2014 The largest of the brachial plexus, and situated between the external cutaneous and the ulnar, arises by two roots, the external common to the median, and the external cutaneous : the internal common to the median, the internal cutaneous, and the ulnar. The fifth, sixth, seventh, and eight cervical and first dorsal nerves consequently concur to form it. Between its two roots is placed the axillary artery. It passes along the inner side of the arm in company with the axillary artery to the bend of the elbow, lying at first to the outside of the vessels, and then a little above the middle of the arm, crosses to its inner side, occasionally, however, continuing all along to its outside. It is slightly overlapped by the inner border of the biceps, having the brachialis anticus to its outside : the latter muscle separates it inferiorly from the ulnar nerve. The upper part of the internal cutaneous nerve runs along its inner side. It sinks into the bend of the elbow behind the semilunar fascia, and in front of the brachialis anticus, passes between the two heads of the pronator radii teres, and is then conducted along the forearm between the flexor digi-torum sublimis and profundus to the annular ligament, behind which it passes; and at the lower border of this becomes expanded, and divides into a series of terminal digital branches.\nThe median nerve gives off no branches during its course along the arm, with the exception of an occasional communicating branch to the musculo-cutaneous below the level of the insertion of the coraco-brachialis ; and a branch which is usually found coming off from the anterior part of the trunk a little above the elbow. This is directed along the brachialis anticus to the pronator teres, which it supplies, and sends a few filaments backwards to enter the articulation.\nThe branches given off in the fore-arm are muscular, interosseous, and cutaneous.\nThe muscular branches for the lower part of the pronator teres, flexor carpi radialis, pal-maris longus, and flexor sublimis, are generally derived from a primary branch, which arises behind the pronator teres a little below the elbow-joint ; the lower part of the flexor sublimis, however, receiving several smaller branches from the main trunk. The branches for the flexor longus pollicis and flexor digi-torum profundus are given off lower down, there being generally one for the former and two for the latter, the outer part of which only is supplied ; the inner part of the muscle being supplied by the ulnar nerve.\nThe anterior interosseous nerve is the most","page":756},{"file":"p0757.txt","language":"en","ocr_en":"SPINAL\ndeeply seated branch of the median, coming off at an acute angle from the trunk, between the origin of the deep-seated muscular branches. It runs vertically downwards in company with, but to the radial side of, the corresponding artery, in front of the interosseous membrane between the flexor digitorum profundus and flexor longus pollicis, giving on either side small filaments to them. Having reached the upper edge of the pronator quadratus, it passes behind that muscle, and terminates either by sending numerous filaments into its posterior surface, or, after having supplied it, perforates the lower aperture of the interosseous membrane, and reaches the back of the carpus.\nThe palmar cutaneous branch is given off at the lower fourth of the fore-arm, passes forwards from beneath the tendons of the flexor sublimis, and behind the fascia, which it perforates a little above the wrist, and divides into an external filament, which, having communicated with the radial, terminates in the skin of the vola major, and an internal descending over the annular ligament to be lost in the skin of the upper part of the palm.\nThe terminal digital branches of the median are derived from two primary branches, into which the flattened and expanded nerve divides, after having passed from beneath the annular ligament. These are external and internal, the former supplying the muscles of the thumb, and sending off three digital branches for the thumb and radial side of the index finger, and rather smaller than the latter, which gives off two digital branches for the opposed sides of the index and middle, and the middle and ring finger. The muscular branch passes in a slightly curved manner outwards and upwards, and terminates in filaments for the supply of the abductor, opponens and flexor brevis pollicis.\nThe first digital nerve is directed obliquely dowmwards and outwards in front of the tendon of the flexor longus pollicis, and near the head of the metacarpal bone, crosses it to its outer side, and continues its course to the extremity of the outer side of the anterior aspect of the first phalanx, where it terminates in dorsal and palmar branches. The dorsal branch winds on to the back of the last phalanx, communicates with the radial, and supplies the skin at the root of the nail ; the palmar continues in the original course of the nerve to the skin at the extremity of the thumb.\nThe second digital nerve, not so oblique in its direction as the first, crosses over the adductor pollicis, gives a filament to it, and is conducted along the inner side of the flexor longus pollicis tendon to the ulnar side of the thumb, sending in its course some filaments backwards to communicate with the dorsal branches of the radial, and terminating in a similar manner to the preceding branch.\nThe third digital nerve is directed in front, and to the outside of the first lumbrical muscle, gives a filament to it, and reaches to about the middle of the outer side of the\nNERVES.\t757\nproximal phalanx of the index finger, where it divides into dorsal and palmar branches. The dorsal branch passes on to the back of the phalanx, communicates with one of the dorsal cutaneous nerves, to form a nerve w hich ends in the integuments of the back part of the last phalanx : the palmar branch passes in the original direction of the nerve, and terminates on the outer side of the distal phalanx by again dividing into palmar and dorsal branches, having a similar distribution to the two first nerves.\nThe fourth digital nerve passes in front of the second interosseous space, gives a filament to the second lumbrical muscle, and about the middle of this space divides into two branches, which are directed along the opposed sides of the middle and index fingers. The fifth passes downwards and slightly inwards in front of the third metacarpal space, gives a filament to the third lumbricus, communicates by a delicate filament with the ulnar, and at the middle of this space terminates in two branches for the opposed sides of the middle and ring finger. The termination of the divisions of the fourth and fifth digital nerves, and the branches given off from them, are exactly similar in distribution to the third digital nerve, giving off, like it, on the proximal and distal phalanx, a dorsal branch. Each of the digital nerves, although running along the sides of the fingers, and giving off in their course numerous cutaneous filaments, which are directed towards the axes of the fingers, are not observed to anastomose with each other.\nThe median nerve in the palm of the hand is situated on a plane anterior to all the flexor tendons, and the trunk before dividing is situated half an inch or more above the level of the superficial palmar arch of arteries which crosses in front of its three internal branches. The accompanying digital arteries are placed somewhat behind, and further from the longitudinal axes of the fingers than the nerves, which, however, in their course send numerous small filaments which wind around them.\nThe ulnar nerve, somewhat smaller than the median, arises from a trunk common to it, the internal cutaneous and the inner head of the median. The first dorsal and last cervical are consequently principally engaged in forming it. Almost immediately after its origin it is directed slightly inwards and outwards from the median, and behind the internal cutaneous, and at the lower part of the axilla appears deeply seated at the inner aspect of the arm, being directed in front of the triceps extensor muscle. Below the level of the coraco-brachialis it perforates the internal intermuscular septum, and becomes surrounded by several fasciculi, derived from the inner head of the triceps, and passes behind the intermuscular septum to gain the space between the internal condyle and olecranon, being here situated between the two heads of the flexor carpi ulnaris. It now inclines downwards and slightly outwards along","page":757},{"file":"p0758.txt","language":"en","ocr_en":"758\tSPINAL NERVES.\nthe inner part of the coronoid process of the ulna, and then takes a vertical course down the fore arm, covered over by the flexor carpi ulnaris, and between it and the flexor digi-torum profundus. It gradually inclines to the surface, and at the lower third of the forearm becomes sub-aponeurotic, and passes from between the flexor carpi ulnaris and inner tendon of the flexor sublimis to the lower part of the anterior surface of the annular ligament, passing along it in a distinct sheath with the artery, in close contact with, and external to, the pisiform and unciform bones, and divides into its terminal branches. In the upper part of the arm the ulnar nerve is in relation with the axillary artery, which is placed between it and the median, nearer however the latter. In the upper part of the fore-arm it is about half an inch or more distant from the artery, but gradually inclines, so as to come in close relation with, but internal to it, in the two lower thirds of the fore-arm, and in the palm of the hand.\nThe ulnar gives off\u2019 no branches in the arm ; and the first that comes off\u2019 from it, is when the nerve is placed between the two heads of the flexor carpi ulnaris. There are several small articular filaments which enter the inner part of the joint, and three or four which are distributed to the above muscle. In the upper third of the fore-arm some filaments are again given off to the flexor carpi ulnaris, and others for the supply of the inner half of the flexor digitorum profundus. About the middle a small branch is given off, which, after sending satellite filaments to accompany the ulnar artery, perforates the fascia, and becomes cutaneous to communicate with the internal cutaneous. The largest branch, however, given off from the ulnar, comes away about two inches above the wrist-joint, and is named, its dorsal branch (dorsalis carpi ulnaris : internal dorsal nerve). This winds downwards and inwards, and having passed between the tendon of the flexor carpi ulnaris and the bone, perforates the fascia at the back of the fore-arm, and becomes cutaneous a little above the styloid process. It runs then along the inner edge of the carpus ; and on the posterior annular ligament terminates in two branches. The inner branch passes along the inner and back part of the metacarpal bone, and phalanges of the little finger, supplying the integument as far as its extremity, and sending in its course some small filaments to the abductor minimi digiti. The outer branch crosses obliquely the tendon of the extensor minimi digiti, and on the fourth intei'osseous space sub-divides. The inner sub-division at the extremity of the space bifurcates in order to supply the opposed sides of the little and ring finger. The outer sub-division at the lower extremity of the third interosseous space having communicated with the dorsal branch of the radial, similarly bifurcates for the supply of the integument of the opposed sides of the middle and ring finger. The dorsalis carpi ulnaris, independently of the above branches, sends numerous filaments to\nthe inner and back part of the wrist and hand, and communicates above with the external or posterior cutaneous.\nThe terminal branches of the ulnar nerve are two in number, a superficial external, and deep internal.\u2014The former, after a very short course, divides into two branches, a small internal, and large external. The internal branch passes along the ulnar side of the little finger to its extremity, giving filaments in its course to the muscles of the little finger. The external passes obliquely across the flexor tendons for the ring finger, gives a filament to the fourth lumbricus, and one of communication with the median, and over the fourth interosseous space at a variable distance from its inferior extremity bifurcates : the divisions of the bifurcation being distributed in a similar manner with the median to the opposed surface of the ring and little finger.\nThe deep branch is directed backwards and outwards between the abductor minimi digiti, and the flexor brevis to the posterior aspect of the adductor minimi digiti, having first given off on the palm a small branch which sends filaments to these three muscles. It passes downwards in a curved manner, the convexity of the curve looking downwards and inwards, and after a short course passes at an acute angle behind the deep palmar arch of arteries. No branches come off from its concavity. From its convexity and back part and outer termination are derived filaments which supply the two inner lumbricales, the palmar and dorsal interossei, the adductor and flexor brevis pollicis. The deep or perforating interosseous branches can be traced through the two layers of interossei to the skin on the back of the hand, where they communicate with the dorsal cutaneous from the radial and ulnar nerves.\nThe musculo-spiral nerve (\u2019radial) slightly larger than the median, arises from the inner and back part of the plexus, and is formed particularly by the three inferior cervical and first dorsai nerves. The trunk from which it arises also gives origin to the circumflex nerve. It passes attirstfrom before backwards, running behind the ulnar, and in front and below the circumflex nerve, and having crossed the conjoined tendons of the teres major, and latissi-mus dorsi, inclines downwards, backwards and outwards to the posterior surface of the humerus, between it and the long head of the triceps. It continues gradually inclining more outwards, till it reaches the lower third of the arm where it gains the outer aspect of the bone, and here it passes forwards in company with the superior profunda artery, to the anterior and outer aspect of the arm lying internal to the outer head of the triceps which it perforates. It is now directed between the supinator longus and brachialis anticus, and then between the latter and extensor carpi radialis longior, and, having reached the outer and anterior part of the elbow-joint, divides into an anterior and posterior terminal branch.\nThe branches given off from the musculo-","page":758},{"file":"p0759.txt","language":"en","ocr_en":"SPINAL NERVES.\n759\nspiral in the arm are numerous, and may be aponeurotic course, perforates the fascia, and arranged into\tdivides about a couple of inches above the sty-\nf Internal cutaneous. Branch loid process into an external large, and internal Internal -1 for the internal head of the terminal-branch. The external branch passes L triceps.\talong the outer aspect of the styloid process ;\nf Branches for the long head of and at the proximal part of the wrist sends a Posterior \\ the triceps. Outer head and communicating loop inwards, to be connected I ancon\u00e6us.\twith the cutaneous palmar branch of the me-\nf Cutaneous filaments to the dian. It then descends on the dorsum of the External | ann External cutaneous. thumb, and supplies its external border. The The internal cutaneous is the first branch of internal branch crosses obliquely the extensoi the musculo-spiral, and continues for some ossis metacarpi and primi internodii pollicis, distance deeply seated to the fascia, which it and divides into a series of branches which perforates above the middle of the arm, and supply the ulnar side of the thumb : both sides descends as one or two filaments along the of the index finger, and the radial side of the inner and back part of the arm to the elbow, middle. These different branches furnish, in where they communicate with the posterior their course along the carpus, several cutaneous filaments of the accessory internal cutaneous, filaments, and some small twigs which coin-The branch for the internal head of the tri- municate with the perforating interosseous of ceps is the next that is given off. It is a the deep branch of the ulnar nerve. Ihe delicate, long nerve, which is directed along most internal division communicates with the the surface of the inner portion of the triceps, dorsalis carpi ulnaris. The two terminal running behind the ulnar nerve to within three branches of the radial are subject to much\nor four inches of the elbow-joint, when it enters the substance of the muscle.\nThe branches for the long head of the triceps are numerous, and enter its anterior surface. The superior branch is reflected upwards, and can be traced as far as the axillary origin of the muscle. The inferior or descending branch is the longest, and courses downwards to near the olecranon before entering it.\nThe branch for the outer head of the triceps and ancon\u00e6us, given off externally to the branches for the long head, is a long slender nerve. It passes down between the outer and middle head to the outside of the olecranon, supplying the outer head in its course, and terminating in the ancon\u00e6us by entering at its anterior surface.\nThe external cutaneous branch is given off below the middle of the arm, as the musculo-spiral is commencing its anterior and outer course. It passes along the outer and back of the arm, and divides into two or three delicate descending filaments which supply the skin, and terminate on the back of the carpus between the posterior branches of the external cutaneous, radial, and dorsalis carpi ulnaris with which they communicate.\nThe musculo-spiral nerve, before giving off its terminal branches, sends filaments to the muscles between which it passes, viz. the bra-chialis anticus, supinator longus, and extensor carpi radialis longior.\nThe anterior terminal branch (radial nerve) is the apparent continuation of the musculo-spiral nerve, though smaller than the posterior terminal branch. It passes between the supinator longus and brevis, lying on the latter, and over-lapped by the former, and gradually approaches, in its descent of the fore-arm, the radial artery ; so that at the middle it is in close contact with, but external to, the vessel. Having arrived at the lower third of the forearm, or a little above, it twists round the deep surface of the tendon of the supinator longus, and appears beneath the fascia on the outer part of the fore-arm, and after a short sub-\nvariation : the external being sometimes larger than the internal, and supplying either both sides of the thumb, or both sides of the thumb and the radial side of the index finger. The internal branch occasionally unites with the outer division of the dorsalis carpi ulnaris, and supplies the opposed sides of the middle and ring fingers.\nThe deep terminal branch (the posterior interosseous or muscular) is larger than the anterior, passes downwards and backwards along the inner aspect of the exterior carpi radialis brevis, gives filaments to it, and reaches the surface of the supinator brevis, supplies it, as it passes obliquely downwards, backwards, and inwards through its substance, to emerge at its lower and posterior portion. It here divides into a posterior and anterior series : the former supplying the extensor carpi ulnaris, the communis digitorum, and minimi digiti, entering at their anterior aspect the latter the deep-seated muscles. One of the latter has a somewhat remarkable course ; is longer and larger than the rest; and passes along the posterior surface of the extensor ossis metacarpi and primi internodii; and at the lower part of the fore-arm becomes placed between the interosseous ligament and the extensor secundi internodii, and indicator, supplies these muscles with one or two twigs, and is conducted in front of the posterior annular ligament to the back of the carpus, where it assumes a gangliform enlargement, from which numerous filaments radiate for the supply of the ligaments and carpal articulations.\nThe circumflex nerve ('axillary) is the most posterior of the terminal branches of the brachial plexus, and is occasionally given off from the musculo-spiral, usually, however, taking its origin from a trunk common to it, and to that nerve, external to winch it is situated. After a short course in the axilla, it soon leaves that space by passing downwards and outwards over the upper part of the axillary border of the subscapularis to enter the quadrilateral space above the teres major, below the","page":759},{"file":"p0760.txt","language":"en","ocr_en":"760\tSPINAL\nteres minor, and between tue humerus and long head of the triceps to terminate in the deep surface ot the deltoid. It gives off in this course branches to the subscapularis and teres minor; that for the latter entering the lower border of the muscle, and prior to dividing into its deltoid branches. \u2014 The cutaneous nerve of the shoulder passes from behind the posterior border of the deltoid, perforates the fascia, and divides into a series of radiating branches, which supply the skin at the upper and back part of the shoulder. The deltoid branches ramify through the substance of the muscle as far as its insertion, and from one of them a filament is given off to the capsular ligament of the shoulder joint.\nThe anterior branches of the dorsal {intercostal) nerves are twelve in number, the first escaping between the first and second dorsal vertebrae, and the last between the last dorsal and first lumbar. They run more or less parallel to each other without forming plexuses, and are destined to supply the thoracic and abdominal parietes, and the skin about the arm and axilla. They present general and special characters. Each branch runs outwards, from its origin, being separated from the posterior root by the intervention of the anterior costo-transverse ligament, to reach the intercostal space, between the pleura and external layer of the intercostal muscles, and below the intercostal vessels. Having communicated by one or two filaments with the thoracic ganglia of the sympathetic, these nerves are continued between the two layers of the intercostals, to about midway between the spine and the sternum, and here they divide into cutaneous and intercostal branches. The cutaneous branches perforate, in a very oblique manner, the external layer of intercostals ; and, after a short course, forwards and outwards, between them and the serratus magnus, either escape between the digitations of the serratus magnus and external oblique, or perforate their fibres, and divide into anterior and posterior branches. This division takes place sometimes when the trunks of the cutaneous nerves are covered by the serratus and oblique. The posterior branches are reflected backwards and upwards, and, after a course of an inch or two between the latissimus dorsi and the skin, terminate in the latter. The anterior branches are directed downwards and forwards, or horizontally, and, after a longer course than the posterior branches, terminate, like them, in the skin.\nThe intercostal branches, though somewhat smaller than the cutaneous, represent the continuation of the anterior branches of the dorsal nerves. They continue in the original course of the latter, below the lower edge of the ribs on the one hand, and the costal cartilages on the other ; and near the border of the sternum above, and the linea alba below, perforate the muscular fibres, and become cutaneous. The trunks of the intercostal nerves and their continuation give off\u201c numerous filaments to the supply of the intercostal\nSERVES.\nmuscles, and several extremely delicate twigs, which frequently pass over the inner aspect of the ribs, to communicate above and below with each other in the intercostal spaces.\nThe special characters of the intercostal nerves are as follow : \u2014\nThe first dorsal nerve, ascending in front, and across the neck, of the first rib, to assist in the formation of the brachial plexus, gives off\u201c only a small intercostal nerve. This comes away soon after the nerve has left the intervertebral foramen, and is directed along the inner surface of the first rib, to the first intercostal space, without giving off\u201c a middle cutaneous branch, and passes along the lower edge of the cartilage to the sternum, by the side of which it perforates the intercostal muscles, and terminates on the skin, at the upper and fore part of the thorax.\nThe second dorsal nerve crosses obliquely over the second rib, external to its neck, to gain the lower part of the first intercostal space, and again crosses the second rib, to reach the second intercostal space on a level with the middle of the former. Its cutaneous branch is of large size, and, supplying the arm with cutaneous branches, is named the inter-costo-humeral, which perforates the second intercostal space. In traversing the axilla it gives off a branch of communication to the accessory internal cutaneous, and one to communicate with the second intercosto-humeral ; the latter united nerve sending filaments to the skin at the upper and anterior part of the arm. Two or three filaments represent the termination of the nerve, cross the lower part of the posterior boundary of the axilla, and terminate in the skin, at the upper and back part of the arm.\nThe cutaneous branch of the third dorsal (the second intercosto-humeral) is smaller than the second, and passes through the third intercostal space : it divides into an anterior and posterior branch ; the former winds upwards, forwards, and inwards, over the lower border of the pectoralis major, to terminate in the mamma and integument ; the latter, having communicated with the second intercostal, sends filaments to the axilla, and terminal branches, which are directed to the outer and anterior part of the axilla to supply the skin, at the upper and back part of the arm.\nThe cutaneous branches of the fourth and fifth dorsal nerves send filaments inwards, to supply the mamma ; and filaments backwards, over the superficial surface of the latissimus dorsi, to supply the skin over the anterior and outer part of the scapula. The intercostal nerves of the eighth, ninth, tenth, and eleventh dorsal nerves perforate the intercostal spaces of the false ribs, pass through the costal attachments of the diaphragm, to get between the external and internal oblique, as far as the border of the rectus, where they give off small cutaneous branches. Entering the sheath of the rectus, they proceed along the posterior surface of the muscle, and terminate, by giving off some filaments, which ramify in its inner part ; and others, which perforate the anterior","page":760},{"file":"p0761.txt","language":"en","ocr_en":"SPINAL NERVES.\t761\nlayer of the sheath, at a variable distance from the linea alba, to supply the skin at the anterior part of the abdomen.\nThe twelfth dorsal nerve is larger than those that have preceded it, and gives a filament of communication to the anterior branch of the first lumbar nerve. It is directed obliquely downwards and outwards, following the course of the last rib, along the lower border of which it runs, passes behind the anterior layer of the transversalis fascia between it and the quadratus lumborum, and, on a level with the apex of the rib, divides into two branches. The cutaneous branch, larger than the abdominal, or continuation of the trunk, perforates, obliquely, the external and internal oblique, gives them some small branches, and then becomes superficial, crosses over the crest of the ilium, and divides into a series of divergent filaments, which lose themselves in the skin of the middle of the glut\u00e6al region. The abdominal branch or continuation of the nerve passes between the internal oblique and transversalis, supplies these muscles, communicates with the first branch of the lumbar plexus, and terminates in the rectus and pyramidalis, and the skin over them.\nThe anterior branches of the lumbar nerves are five in number, intervening between the corresponding branches of the dorsal and sacral nerves. They increase in bulk from above downwards, communicate with each other by anastomosing branches, and with the lumbar ganglia by filaments, which come from the latter, or the main trunks. These filaments of communication with the sympathetic, vary in number from two to five, and are in close relation with the convexities of the bodies of the lumbar vertebrae. Several nerves are also given to the supply of the psoas muscle.\nThe anterior branch of the first lumbar nerve is small, much resembling the anterior branch of the last dorsal. Having quitted the intervertebral foramen, it immediately divides into three branches ; two external and small, viz. : \u2014 the great and small musculo-cutaneous; the other internal and vertical in direction, and forming the anastomosing branch with the second.\nThe anterior branch of the second lumbar nerve, twice as long and broader than the first, gives off the genito-crural and external cutaneous, and communicates by a long anastomosing branch with the third.\nThe anterior branch of the third lumbar nerve, nearly twice as large as the second, is directed downwards and outwards, and gives off, at an acute angle, a large external branch, concurring to form the anterior crural, and an internal, the obturator neive: it communicates with the fourth nerve by one branch connected with the main trunk, or by two connected with its two branches.\nThe anterior branch of the fourth lumbar nerve is somewhat larger than the third. It divides into an external branch connected with the external division of the third, to complete the anterior crural ; and internal to assist\nin the formation of the obturator. Its terminal branch is the anastomosing branch with the fifth, internal to the other two, and vertical in direction.\nThe anterior branch of the fifth lumbar nerve is the largest of all the series, and terminates in the sacral plexus, and is named the lumbosacral nerve.\nThe lumbar or lumbo-abdominal plexus is rather intricate, and formed by the anastomosis of the anterior branches of the five lumbar nerves. Placed upon the sides of the lumbar vertebrae between the transverse processes, and enveloped by the fasciculi of the psoas muscle, it presents, when the latter are dissected away from it, an irregularly triangular appearance ; the apex of the triangle being above, and the base below. In the former situation, the nerves forming it are comparatively delicate, and unite with each nearer the vertebral column than the latter ; it communicates above with the twelfth dorsal nerve, through the medium of the \u201c dorso-lumbar,\u201d and below, with the sacral plexus, through the medium of the \u201c lumbo-sacral \u201d nerve. The branches given oft\u2019from it may be divided into abdominal and crural: the former being given off from its upper ; the latter, from its inferior or terminal portion.\nThe abdominal series is represented by the musculo-cutaneous nerves, and the genito-crural. The crural series by the external cutaneous, crural, and obturator. The musculo-cutaneous nerves are two in number: the upper being three or four times larger than the lower.\nThe upper musculo-cutaneous (large abdominal, ilio-hypogastric, ilio-scrotal) is the highest of the branches of the lumbar plexus, taking its origin from the first lumbar nerve. It makes its appearance from behind the psoas muscle about an inch and a half below the last dorsal nerve, runs obliquely downwards and outwards across the quadratus lumborum in the subperitoneal tissue, and about an inch above the crest of the ilium, perforates the tendon of the transversalis, and is continued between it and the internal oblique to the middle of the crest of the ilium, where it divides into two branches, an external and internal. The external passes obliquely between the internal and external oblique, and at the anterior-third of the crest of the ilium, winding on to the glut\u00e6al region, divides into an anterior and posterior series of filaments ; the one supplying the integument over the tensor vaginae femoris, the other that over the anterior part of the glut\u00e6us m\u00e9dius. The internal branch, or the continuation of the nerve, after a course of an inch or two, communicates with the small musculo-cutaneous by a loop which usually passes round the internal circumflex ilii vessels. It then divides into an abdominal and scrotal branch. The abdominal runs parallel to the corresponding branch of the last dorsal, generally communicates with it, and passes through the tendons of the internal and external oblique, and is distributed to the skin at the inner part of the groin. The inguinal,","page":761},{"file":"p0762.txt","language":"en","ocr_en":"762\tSPINAL\npubic, or scrotal branch runs parallel to Pou-part\u2019s ligament, in company with, but above, the small external cutaneous, reaches the external ring, and divides into internal terminal branches supplying the skin over the pubis ; and external ones supplying the scrotum in the male, and the labia pudendi in the female.\nThe lower musculo-cutaneous (small muscu-lo-cutaneous\u2014small inguino-cutaneous\u2014small abdominal) is a thin delicate nerve, arising generally from the first lumbar, sometimes from the large musculo-cutaneous, is directed downwards and slightly outwards, along the back part of the psoas, a little in front of the inner border of the quadratus lumborum, crosses the iliacus internus about its upper fourth, and reaches the anterior third of the crest of the ileum. There it is lost by communicating with the large musculo-cutaneous, or, as is generally the case, passes after this communication as a very delicate nerve between the internal oblique and transversalis, supplying the lower part of these muscles, but principally the latter, and parallel to Poupart\u2019s ligament, perforates the former muscle at the outer ring, and terminates in a manner similar to the pubic or scrotal branch of the upper musculo-cutaneous, in the scrotum and pubic integument.\nThe genito-crural nerve (external spermatic \u2014 internal inguinal) derived from the second lumbar nerve, and sometimes from the communicating branch between the first and second, passes directly forwards to the anterior part of the psoas muscle, along which it descends vertically to the femoral arch. It lies behind the spermatic vessels, and is crossed by the ureter. Having reached Poupart\u2019s ligament, it divides into two branches, an internal or genital, and an external or crural. The genital is directed across the external iliac artery (to which it supplies a few filaments) to the chord, lying below it as far as the internal ring. Prior to entering the inguinal canal the transversalis and internal oblique receive a few reflected branches from it. The nerve then accompanies the choi\u2019d, crosses the epigastric vessels, supplies the cremaster muscle, runs immediately in front of Gimber-nat\u2019s ligament, and terminates in the scrotal integument in the male, and labia pudendi in the female, supplying also the integument at the upper and inner part of the thigh, and communicating with the inferior pudendal nerve. The crural branch (femoral-cutaneous), having given off several delicate filaments to be distributed to the transversalis and internal oblique, crosses the circumflex ilii vessels, passes underneath Poupart\u2019s ligament, a little to the outside of the femoral artery, pierces the fascia immediately below the ligament, and becomes cutaneous, supplying the skin of the thigh at the middle part of its upper third. The division of the genito-crural into its terminal branches is subject to considerable variation, sometimes taking place either immediately after it has emerged from within the psoas, or within the psoas directly after its origin from the plexus.\nNER\\ES.\nThe crural division is at times also extremely small, the external cutaneous then having a more extensive distribution than ordinary.\nThe external cutaneous (external inguinal) is a branch from the second or from the second and third lumbar, or is occasionally derived from the outer part of the crural nerve. It passes from beneath the outer border of the psoas below its middle, runs across the iliacus towards the space between the two spinous processes of the ilium, lying behind the transversalis fascia. It then passes beneath Poupart\u2019s ligament, and divides into an interior and posterior branch. The posterior passes outwards and backwards over the fascia, covering the tensor vaginae femoris, and supplies the integument at the upper, outer, and back part of the thigh. The extent of distribution of this branch is subject to variation, owing to the circumstance of a corresponding branch being occasionally supplied either by the great musculo-cutaneous, or by the genito-crural, when the trunk of the external cutaneous itself comes from the anterior crural. In such instances this branch is small and insignificant, if it exist at all. The anterior branch becoming cutaneous about the upper fifth of the thigh, soon divides into an external and internal, directed downwards, over the fascia covering the anterior and outer part of the rectus muscle. The external division terminates in the integument at the middle third of the outer part of the thigh ; the internal at the lower third of the thigh, above and to the outside of the patella.\nThe crural nerve (femoral) is by far the largest branch of the lumbar plexus, and is placed in the substance of the psoas muscle between the external cutaneous, and the obturator, below the level of the former and above that of the latter, from which it diverges at an acute angle. It is formed by the union of the second with the outer branch of the third lumbar nerve, by part of the fourth, and generally by their communicating branch. It is destined to supply the integuments of the front of the thigh, and all the muscles at its anterior and outer portion.\nHaving emerged from the psoas muscle it is directed forwards and outwards between that muscle and the iliacus to Poupart\u2019s ligament, under which it passes, and entering the thigh becomes flattened and expanded, and divides into a series of divergent terminal branches, the trunk occasionally bifurcating before so doing.\nThe nerve in its course within the pelvis is situated behind the iliac division of the transversalis fascia, external to the iliac artery, and gives off a few branches to the psoas and iliacus. Outside the sheath of the femoral vein and artery it is separated from the latter by the intervention of the psoas muscle.\nThe terminal branches may be divided into superficial and deep ; the first consisting of the internal, and middle cutaneous, and branches to the femoral vessels and pcctinceus : the second of branches to the quadriceps extensor cruris, and the cutaneous branch of the inner and","page":762},{"file":"p0763.txt","language":"en","ocr_en":"SPINAL NERVES.\n763\nanterior part of the ltnee and leg, viz. the internal saph\u00e6nus.\nThe internal cutaneous nerve (internal musculocutaneous) directed along the inner border of the sartorius muscle, perforates the fascia at the lower third of the leg, occasionally perforating the sartorius before so doing. Having given off several cutaneous branches, which form a connexion with the cutaneous branch of the obturator in this situation, it continues its course towards the lower and inner part of the thigh, having previously communicated with a branch perforating the sartorius, and coming from the internal sa-ph\u00e6nus. From the thigh it passes along the inner edge of the patella, describing a curve, and sending some terminal filaments from its concavity upwards to unite with the middle cutaneous : others, from its convexity downwards, to communicate with the reflected branch of the saph\u00e6nus itself, and also its accessory branch.\nThe accessory saph\u0153nus nerve (Cruveilhier) takes its origin from the internal cutaneous ; from the anterior crural in company with the latter ; or from the trunk of the saph\u00e6nus itself. It soon divides into a superficial internal branch, which passes from within the sheath of the sartorius muscles over the femoral vessels, and adductor longus, and at the junction of about the upper with the middle third of the thigh meets with the internal saph\u00e6na vein, which it accompanies as far as the knee-joint, in which situation it communicates with the internal saph\u00e6nus and cutaneous branch of the obturator. The external branch, situated behind the level of the superficial, is directed inwards to the femoral artery, runs along its outer part in close contact with it, and accompanies the vessel in Hunter\u2019s canal to its lower extremity. It then quits the artery, is directed in front of the tendon of the adductor magnus, to the upper part of the internal condyle of the femur, where it becomes cutaneous, anastomosing with the internal cutaneous above, with the reflected branch of the saph\u00e6nus below, and sending cutaneous branches over the inner and middle part of the patella. This branch has been termed by Cruveilhier the satellite nerve of the femoral artery : and the superficial branch might with equal propriety be denominated the satellite nerve of the saph\u00e6na vein. The accessory saph\u00e6nus is subject to considerable variation, both as to size and origin.\nThe middle cutaneous nerve perforates the fascia three or four inches below Poupart\u2019s ligament, crosses the sartorius muscle, and is directed over the inner part of the rectus to terminate in the cuticle over the front of the patella, anastomosing above with the external cutaneous nerve, and below with the internal cutaneous and accessory saph\u00e6nus. It frequently divides about the middle of the thigh into two branches, which run parallel with each other. The internal and middle cutaneous nerves not unfrequently perforate the sartorius muscle before becoming cutaneous, the first at the middle, the second at its upper\npart. They are consequently described also as the inferior perforating cutaneous, and the superior perforating cutaneous.\nThe nerve to the femoral vessels is very delicate, and arises internal to the internal cutaneous, sometimes however coming off from the lumbar plexus. It is directed downwards and inwards to the femoral vessels, and divides into a series of filaments, one or two of which are directed through the cribriform fascia to the saph\u00e6na vein, along which they pass in a tortuous manner till lost by communicating with the internal branch of the accessory saph\u00e6nus, about the middle of the thigh. The remainder pass, some behind and some in front of the femoral vessels, and terminate at the lower third of the thigh, by uniting with the external branch of the accessory saph\u00e6nus.\nThe branches to the pectin\u0153us are directed inwards behind the femoral vessels, and in their course to this muscle generally send a few filaments to the psoas.\nThe deep-seated muscular branches arise external to the internal saph\u00e6nus nerve, and behind the superficial already described : and are from within outwards : Branches for the vastus internus and crur\u00e6us : branch for the rectus : and branches for the vastus externus, which are the deepest of all.\nThe branch for the vastus internus (short saph\u00e6nus), taking its origin in close contact with the internal saph\u00e6nus, from which it not unfrequently arises, is directed in company with, but external to it, along with the femoral artery. It separates a little below the middle of the thigh from the vessels, and is directed to the external aspect of the vastus internus, to enter it at its lower one third ; but before so doing gives off a superficial articular branch, which passes in front of the outer border of Hunter\u2019s canal ; in this situation occasionally communicating either with the cutaneous branch of the obturator, or the outer branch of the accessory saph\u00e6nus ; crosses through the superficial muscular fibres of the vastus to its aponeurotic termination, which it perforates. It is then reflected forwards, upwards, and outwards, and terminates in two or three filaments, one of which passes behind the ligamentum patella, entering the anterior part of the knee-joint ; the others pass in front of the patella, to supply the periosteum and skin over it.\nThe nerve for the crur\u00e6us, shorter than that for the vastus internus, enters the upper and inner part of the muscle, extends as far as its lower part, and gives off filaments to the deep-seated portion of the muscle (the sub-crur\u00e6us) to the periosteum and upper part of the synovial capsule.\nThe branch for the rectus enters the upper part of its posterior aspect, and divides into a superior branch which passes transversely outwards, and a long vertical branch which passes along its inner side to the lower portion.\nThe branch for the vastus externus frequently arising in company with that for the rectus, is directed downwards and outwards between","page":763},{"file":"p0764.txt","language":"en","ocr_en":"764\tSPINAL\nthat muscle and the crur\u00e6us, and, in company with the descending branches of the external circumflex artery, enters its inner aspect by two or three divisions, having previously given off a superficial articular branch. This filament, the analogue of the corresponding branch of the vastus internus, creeps beneath the superficial muscular fibres, and near the patella becomes cutaneous, some of the terminal filaments passing behind the outer part of the ligamentum patella, others over the patella, where they are lost in the skin and periosteum.\nThe saph\u00e6nus nerve (cracpns, manifest), the most internal of the deep-seated branches, and arising behind and external to the middle cutaneous, is the largest branch of the crural. It passes downwards and outwards towards the femoral artery, and, about two or three inches below Poupart\u2019s ligament, enters its sheath. The nerve first lies outside and behind the artery ; but a little before the vessel enters Hunter\u2019s canal it gets anterior to it. During the course of the artery downwards and outwards, to enter the ham, the nerve inclines forwards and inwards, and quits the canal, in company with the anastomotic artery, a little above the level at which the femoral vein and artery pass out. It now follows the course of the sartorius lying behind it, to the inner condyle, and one or two inches above the head of the tibia is placed between that muscle and the gracilis, and gives ofl^ before continuing its course, the cutaneous tibial or reflected branch. This nerve first runs parallel lor a short distance with the tendons of the two muscles, then sweeps downwards, forwards, and slightly upwards over the fascia covering them and their tendinous expansions, and across the spine of the tibia to the skin at the upper and outer part of the leg, about two or three inches below the head of the tibia, communicating above with the internal cutaneous.\nThe continuation of the nerve, or what may be termed the posterior trunk, inclines slightly backwards from between the tendon of the sartorius and gracilis, and on a level with the knee-joint is a little to the inner and back part of the tendon of the latter. Having received its connection with the cutaneous branch of the obturator, it passes in company with the saph\u00e6na vein into the region of the leg, inclining slightly forwards to the back part of the inner border of the tibia. Having supplied the integuments at the upper, inner, and anterior part of the leg, it inclines slightly backwards about its middle, sends filaments to communicate with the continuation of the cutaneous branch of the obturator at the posterior part of the leg. It then again inclines forwards, and terminates about three or four inches above the ankle in two branches. The anterior terminal, the smaller of the two, supplies the skin at the lower sixth of the inner and front part of the leg, and over the front of the ankle joint, a few of the branches entering the articulation. The posterior terminal, apparently the\nNERVES.\ncontinuation of the trunk, supply the integuments over the inner malleolus, upper, inner, and back part of the foot.\nThe saph\u00e6nus nerve not unfrequentlyr, in its course in the thigh, in company with the femora! artery, gives off, at a variable height, usually however at the lower fourth of the leg, a small branch corresponding more or less with the distribution of the outer division of the accessory saph\u00e6nus. The internal saph\u00e6nus nerve first iies behind the corresponding vein ; then in front of it to the middle third of the leg, when it again is placed behind it : an inch or two before it divides into its terminal branches, it is again anterior to it, the latter passing over in front, and the other behind.\nThe obturator nerve, derived from the third and fourth, and sometimes also from their internal intercommunicating branch, is much smaller than the anterior crural, and rounded. It perforates the inner border of the psoas, along which it is conducted to the pelvis, a little below the level of which it runs to between the external and internal iliac vessels. It then passes obliquely behind the external iliac vein, crossing it at a very acute angle, and reaches the obturator foramen in company with, and above, the obturator artery. It passes through this foramen into the thigh, and terminates by dividing into superficial and deep divergent muscular branches, situated behind the pectin\u00e6us and adductor longus. Soon after its origin a small nerve, the accessory obturator, is occasionally observed to proceed from the outer part of the trunk. It passes in company with the femoral vein, anterior and internal to it, beneath the femoral arch, over the horizontal ramus cf the pubis, and external to the pectin\u00e6us. It is then directed a little inwards, and divides into several branches, some of which enter the joint through the anterior part of the capsular ligament ; others supply the posterior surface of the pectin\u00e6us, and the remainder, as the continuation of the nerve, terminate by communicating either with the upper part of the trunk of the obdurator itself, or with the branch of the nerve destined for the adductor longus.\nThe obturator nerve, in passing through the subpubic canal, gives off two or three branches to the obturator externus muscle : one penetrating its upper edge, the others its anterior surface. Some articular filaments are also sent off in this direction, and accompany some of the branches of the inferior division of the obturator artery, beneath the transverse ligament to the hip-joint. The relation of these filaments as to size and numbers, however, is not constant, being in the inverse proportion to the size and number of branches given off from the accessory obturator, which is not unfrequently absent.\nFrom the superficial branch is given off a long filament internally to the gracilis muscle, which runs for about two inches along the outer surface of the muscle before entering it, another to the posterior surface of the pec-","page":764},{"file":"p0765.txt","language":"en","ocr_en":"SPINAL NERVES.\t705\ntin\u00e6us, which varies in its size according to whether this muscle be supplied by the accessory obturator or not : and a third to the adductor longus, which also enters its posterior surface.\nThe most important branch, however, is the long cutaneous branch which emerges from behind the lower border of the adductor longus muscle, passes in the fascia behind the internal saph\u00e6na vein as far as the knee joint, where it perforates the fascia, and becomes cutaneous at the anterior border of the tendon of the gracilis muscle. In this part of its course, a little below the upper third of the thigh, it communicates either with the internal branch of the accessory saph\u00e6nus, or with a branch occasionally given off from the saph\u00e6nus itself, and which accompanies the saph\u00e6na vein to the knee joint. It gives off cutaneous branches to the middle of the thigh, forming, with the above nerve, a more or less intricate plexus. Having perforated the fascia on a level with the knee joint, above it, or a little below it, it communicates with the trunk of the internal saph\u00e6nus (being occasionally only in apposition with it), and internal cutaneous nerve. It terminates by being directed downwards and backwards to above the lower part of the poplitaeal region, and continues to give off cutaneous branches, till it is lost in the integument at the inner and back part of the leg to within two or three inches of the ankle : having previously sent filaments of communication to the continuation of the saph\u00e6nus nerve.\nThe deep branch of the obturator runs generally behind the adductor brevis, and divides into two branches, one ramifying through the centre of that muscle : the other, for the supply of the adductor niagnus. From the latter is given off a small articular nerve for the knee joint, which is directed downwards and outwards, towards the attachment of the adductor magnus to the linea aspera, perforates this attachment below the middle of the thigh, and is directed with the poplitaeal artery into the ham,winding around the artery, and giving off an internal delicate branch, which enters the knee joint through the ligament of Winslow.\nThe Anterior Branches of the Sacral Nei ves are six in number, and escape from the anterior sacral foramina, decreasing in size from above downwards, and presenting, consequently, characters reverse to what obtain in the corresponding branches of the lumbar nerves. They communicate with the sacral ganglia of the symphathetic, the filaments of communication being usually two between each nerve and the sympathetic.\nThe first nerve, smaller than the lumbosacral nerve, extends more obliquely downwards and outwards, and having passed from the first sacral foramen, unites with it at an acute angle, and communicates with the second nerve.\nThe second nerve, somewhat smaller than the first, passes more obliquely downwards and outwards from the second anterior sacral foramen, and, having communicated with the\nthird, enters the sacral plexus, sometimes bifurcating previously.\nThe third nerve, about one-third the size of the second, comes from the third sacral foramen, and passes more horizontally outwards to the sacral plexus, having communicated with the second by a delicate filament sent in front of a portion of the pyriformis intervening between it and the second nerve.\nThe fourth nerve, considerably smaller than the third, passes from the fourth sacral foramen, communicates above and below with the third and fifth nerve, and terminates in three sets of filaments. One, usually in the form of a single trunk, is directed a little downwards and outwards, between the levator ani and the eoccyg\u00e6us muscle, gives branches to them, and finally becomes cutaneous. This filament in its course generally furnishes a small twig which perforates the great sacro-sciatic ligament, and terminates in the skin over the border of the coccyx. A second, as a single small trunk, passes to enter the sacral plexus. The third series anastomose freely with the hypogastric plexus, and then form of themselves a loose kind of interlacement, from which branches are given off to the rectum sides of the bladder, prostate, and vesicul\u00e6 s\u00e9minales, and the vagina in the female. The levator ani generally receives one or two filaments, a distinct twig entering the middle, the other supplying the anterior part, after ramifying on the prostate.\nThe fifth passes from the fifth anterior sacral foramen, communicates above and below with the fourth and sixth, and sends a filament which perforates the coccyg\u00e6us muscle, supplies it, and terminates on the skin to the side of it.\nThe sixth (anterior branch of the eoccyg\u00e6al nerve) is extremely delicate, passing between the lower cornu of the sacrum, and the upper border of the coccyx, communicates within the bone with the descending branch of the fifth, and terminates by passing along the border of the coccyx in the substance of the sacro-sciatic ligament to become cutaneous. Some filaments are given off from it which supply the coccyg\u00e6us ; others perforate the ligament, and are lost in the substance of the glut\u00e6us maximus.\nThe Sacral Plexus (sciatic) is formed by the lumbo-sacral nerve and the four upper anterior branches of the sacral nerves, principally, however, by the convergence of the three upper : the fourth sacral nerve sending merely a small filament of communication. The branches that contribute to its formation enter it at once, at a more or less acute angle, without any complex subdivision, as usually occurs in other plexuses. It has a well marked triangular figure, the apex being indicated by the line of convergence of the different trunks : the base by the trunks as they issue from the sacral foramina. It rests upon the pyriformis muscle, the internal iliac vessels separating it from the pelvic viscera, being however in immediate relation with a layer of pelvic fascia. Before terminating in the great sciatic nerve,","page":765},{"file":"p0766.txt","language":"en","ocr_en":"766\nSPINAL NERVES.\nthe plexus gives off a series of anterior and posterior branches. Of the former are observed, a nerve for the obturator internus, and the internal pudic : of the latter, the superior glut\u00e6al, inferior glut\u00e6al, nerves for the pyriformis, gemelli, and qnadratus femoris.\nThe nerve for the obturator internus takes its origin from the upper and outer part of the plexus, being derived from the lumbo-sacral and first sacral. It passes behind the spine of the ischium, and the lesser sacro-sciatic ligament, reenters the pelvis at the lesser sciatic notch, and is distributed by three or four branches within the inner aspect of the muscle.\nThe internal pudic nerve, arising from the lower part of the plexus, and generally derived from the third and fourth nerves, passes behind the spine of the ischium, internal to the pudic artery, in company with the preceding, and then enters the ischio-rectal fossa, where it divides into a superior and inferior branch.\nThe superior branch (the dors il nerve of the penis) ascends in company with the internal pudic artery, but above it, between the obturator internus and the levator ani, to pass between the two layers of the triangular ligament : perforating the anterior layer immediately under the pubic arch it gains the dorsum of the penis, in which situation it is placed in the fold of the suspensary ligament, and inclines inwards to the median line. Having given off one or more external branches, which run superficially as long and slender filaments along the upper and outer part of the penis, supply the corpora cavernosa and their integument, and are conducted as far as the prepuce, the nerve continues its forward direction. It passes to the side of the median line, sends numerous filaments to the skin ; communicating branches to the nerve of the opposite side; and some to accompany the dorsal vein of the penis; and at the root of the glans penis, penetrates deeply between it and the corpus cavernosum,and terminates by sending numerous filaments throughout its substance.\nThe inferior branch (Perin\u00e6al nerve\u2014superficial perin\u00e6al) perforates the obturator fascia at the inner and anterior part of the tuberosity of the ischium, and divides into two branches, an anterior and superior, having previously given off a posterior branch, named by Cruveilhier the external perin\u00e6al, which passes through the obturator fascia behind the tuberosity of the ischium. It runs in company with, but external to, the anterior branch, superficial to the crus of the penis, and terminates by supplying the lower and anterior part of the scrotum where it gives off filaments on the inside to unite with some from the anterior branch, on the outside to communicate with the long inferior pudendal branch of the lesser sciatic. The anterior branch passes in the interval between the accelerator urin\u00e6 and the erector penis, internal to the preceding, and inclines a little forwards and inwards, and ends in a series of long filaments, which communicate laterally with the external perin\u00e6al, and send branches to the middle of the lower and anterior part\nof the skin of the scrotum, some of them being conducted along the skin at the lower aspect of the penis as far as the prepuce. The superior branch soon divides into a series of muscular branches, after having passed above the transversalis perin\u00e6i muscle. Some are sent inwards to the external sphincter, levator ani, and accelerator urin\u00e6 : others to the erector penis ; the termination of the nerve being represented by a small branch, which passes into the substance of the bulbous portion of the urethra.\nThe pudic nerve not unfrequently gives off the inferior h\u00e6morrhoidal (anal), which passes along its inner side, is directed through the obturator fascia to the ischio-rectal space which it traverses to the side of the rectum, and at the upper border of the external sphincter divides into a series of filaments, the anterior of which communicate with the superior branch of the perin\u00e6al, and supply the front of the sphincter and the skin over it. The middle and posterior series supply the sides and back part of the sphincter. Some filaments are given off externally, which pass over the great trochanter, and communicate with the long inferior pudendal nerve. The skin about the anus is also freely supplied.\nThe inferior h\u00e6morrhoidal, when not a branch of the pudic, is given off from the sacral plexus.\nThe superior glut\u00e6al nerve is derived either from the lumbo-sacral nerve only, or from two distinct roots, the one from it and the other from the back part of the first sacral nerve. The former source of origin usually obtains ; and in the latter the root from the sacral nerve is not more than half as long as that from the lumbo-sacral. It passes out as a single trunk at the upper and fore part of the border of the sacro-sciatic notch, in front, and above the pyriformis, and divides into a superior and inferior branch.\nThe superior branch takes the course of the superficial trunk of the corresponding artery, courses along the convex border of the glut\u00e6us minimus, and supplies principally the upper and back part of the glut\u00e6us m\u00e9dius. The inferior branch is directed downwards, forwards, and outwards between the two glut\u00e6i, and, after a short course, divides into a superficial branch, supplying the upper and anterior part of the glut\u00e6us m\u00e9dius ; and a deep branch running across the glut\u00e6us minimus, supplying it and the m\u00e9dius, and terminating near the great trochanter, by entering the substance of the tensor vaginae femoris, at the lower, inner, and back part of its sheath.\nThe inferior glut\u00e6al nerve (lesser sciatic) arises from the back part of the sacral plexus by one or more roots. It emerges from the pelvis at the lower and anterior part of the great sacro-sciatic notch, either as a single, or as two, or three, trunks, below the pyriformis, and about a quarter of an inch behind and internal to the great sciatic. It is directed between the tuberosity of the ischium, and the great trochanter, but nearer the former,","page":766},{"file":"p0767.txt","language":"en","ocr_en":"SPINAL NERVES.\n767\nover the back and inner part of the gemelli, and divides into muscular and cutaneous branches. The muscular branches are long and numerous, being destined to supply the glu-t\u00e6us maximus. One series are directed outwards, upwards, and forwards, and, entering its anterior surface, ramify through the substance of the muscle, as far as its upper and anterior part. The other series are directed downwards, backwards, and outwards, over the tuberosity of the ischium, and supply the lower and back part of the muscle.\nThe inferior glut\u00e6al having emerged from beneath the lower border of the glut\u00e6us maximus, divides'into its two terminal branches, perin\u00e6al cutaneous, and cutaneous branch to the thigh and upper part of the leg. The perin\u00e6al cutaneous nerve is reflected upon the lower border of the glut\u00e6us maximus, and describes a curve, the concavity of which looks towards the sacrum. It soon divides into an external large branch, supplying the skin in the glut\u00e6al region, and an internal small branch (the long inferior pudendal of Soemmering), which passes in a curved manner beneath the tuberosity of the ischium. It is then directed beneath the fascia of the upper and inner part of the thigh, running parallel to the ascending ramus of the ischium, and at or near the junction of the latter with the descending ramus of the pubis, perforates the fascia, and becomes cutaneous, supplying the skin in the perin\u00e6um ; it anastomoses either with the superficial perin\u00e6al, or the external perin\u00e6al nerve, and sends terminal branches to supply the inner and outer portions of the scrotum, and the lower part of the skin of the penis.\nThe cutaneous branch to the back of the thigh and upper part of the leg.\u2014 The continuation of the trunk of the inferior glut\u00e6al is situated anterior and external to the above-named branches. It passes obliquely over the inner and back part of the biceps muscles, and, a little above the middle of the thigh, ordinarily divides into two branches. The small external branch passes downwards, forwards, and outwards to the upper part of the lower third of the thigh, in which situation it anastomoses with the external cutaneous nerve of the lumbar plexus. The large internal branch runs down a little to the inside of the median line of the thigh to the skin in the poplit\u00e6al region, where it divides into external terminal filaments, supplying the skin over the outer and back part of the tibia and fibula, and internal filaments, some of which go to the skin at the inner part of the poplit\u00e6al region, others very small, accompanying and surrounding the external saph\u00e6na vein, communicate below the middle of the leg with filaments given off from the external saph\u00e6nus nerve.\nThe nerve for the pyriformis passes below the level of the superior glut\u00e6al nerve, from the middle of the back part of the plexus, generally taking its origin from the third sacral nerve. It is distributed to the anterior surface of the muscle.\nThe nerves for the gemelli and quadralus fe-\nrions pass from the plexus along the lower part of the pyriformis, close to the os inno-minatum, to the anterior surface of the muscles. That for the quadratus femoris gives off' a few branches to the capsular ligament, one of which enters the articulation, and usually sends off the nerve which supplies the inferior gemellus. This nerve comes off' frequently from the upper part of the great sciatic.\nThe great sciatic nerve (the sciatic, ischi-atic, femoro-poplit\u00e6al), the largest nerve in the body, is formed by the convergence of a branch of the fourth lumbar, the lumbo-sa-cral, and the three or four upper sacral nerves ; represents the termination of the sacral plexus, and is destined to supply the muscles at the back part of the thigh, and the muscles and integuments of the leg and foot. It escapes from the pelvis, from beneath the lower border of the pyriformis, as a flattened ribbon-shaped nerve, about half an inch broad, soon becomes rounded, and- continuing its course from between the great trochanter and tuberosity of the ischium, descends with a slight inclination outwards to the back part of the thigh, a little to the outside of the median line, as far as, or somewhat above, the level of the upper angle of the poplit\u00e6al space, where it divides into terminal branches, the peron\u00e6al and posterior tibial. This division occasionally takes place within the pelvis, in which instances the outer division passes either between the lower fascicles of the pyriformis or above the muscle, the inner beneath the lower edge of the muscle. In some instances it takes place while the nerve is placed between the trochanter and tuberosity: in others, again, the two trunks are distinct as far as this situation, where they again unite, and subsequently divide in the poplit\u00e6al space. _ In the upper part of its course the nerve is rather deeply seated, being covered over by the glut\u00e6us maximus, and having behind and internal to it the branches of the inferior glut\u00e6al nerve. At the lower border of the tendon of the glut\u00e6us maximus it is crossed by the long head of the biceps, and in the remainder of its course is covered only by the fascia.\nIt is in relation in front with the two gemelli and obturator internus, the quadratus femoris and adductor magnus. Behind these muscles it passes successively from above downwards, is in close contact with the superior, and separated from the adductor magnus by a quantity of fat and cellular membrane. The branches given off' from the sciatic nerve are muscular and articular. The muscular branches come away above the middle of the thigh, with the occasional exception of that for the short head of the biceps, which arises near the middle.\nThere are several branches for the long head of' the biceps, some of which ascend to be distributed to the muscle at its origin; others descend for some distance, and enter its anterior surface.\nThe nerve for the semi-tendinous is a long delicate filament, which usually passes down","page":767},{"file":"p0768.txt","language":"en","ocr_en":"7G8\nSPINAL NERVES.\nto the lower third of the thigh before it enters its surface.\nThe semi-membranosus generally receives two or more branches : and from the lower is not unfrequently derived a branch for the adductor magnus, which also receives a branch from the main trunk.\nThe articular nerve is usually given about the middle ; but as this nerve, in the majority of instances, is derived from the peron\u00e6al, it will be described with that nerve.\nThe peron\u00e6al nerve (external poplitaeal \u2014 external poplit\u00e6al-sciatic) is more superficial, and not much more than a third the size of the posterior tibial. It is directed downwards and outwards along the inner edge of the biceps muscle, behind the outer condyle of the femur, the outer head of the gastrocnemius, and the outer and back part of the head of the tibia, to below the head of the fibula, where it divides into four branches, the anterior tibial, and musculo-cutaneous, the former being larger than the latter.\nThe peron\u00e6al nerve, during this course, gives off superficial cutaneous branches, and occasionally deep articular: the former being represented by the peron\u00e6al cutaneous and peron\u00e6al saph\u0153nus, the latter by the superior and inferior external articular.\nThe peron\u00e6al cutaneous proceeds from the back part of the nerve, generally an inch or two after its commencement. Having passed superficially with the trunk as far as its termination, and having supplied the integuments in its course, it gives branches on the one hand to the integuments immediately on the outside of the external saph\u00e6nus, and on the other over the upper part of the pero-n\u00e6us longus, the middle terminal filaments extending below the middle of the leg, and communicating with cutaneous branches from the external saph\u00e6nus.\nThe peron\u00e6al saph\u00e6nus (communicans fibulae\u2014 communicating saph\u00e6nus) usually taking its origin above and to the inside of the peron\u00e6al cutaneous, is directed downwards and inwards beneath the skin, and communicates with a corresponding branch from the posterior tibial to form the external saph\u00e6nus. This communication is very variable as to situation, usually taking place below the middle of the leg, where it perforates the fascia, occasionally, however, in the lower part of the poplitaeal space in front of the fascia. The nerve now and then runs quite distinct from its corresponding branch, which consequently in these instances entirely constitutes the external saph\u00e6nus. It is either very small, terminating about the middle of the leg, or divides opposite the lower part of the tendo Achillis into branches which pass over the lower part of the peron\u00e6us longus to the skin of the external malleolus, where they communicate with small descending branches from the musculo-cutaneous ; and into those which supply the skin at the lower and outer part of the heel, communicating in the interval between the heel and malleolus with branches from the external saph\u00e6nus.\nThe deep articular branches are external and internal, the one arising above the other. They are thus described by Mr. Ellis * : \u2014 tc The superior external articular nerve, arising either from the trunk of the sciatic or the external poplitaeal in the case of a high division of the sciatic, is a long slender nerve, which descends deeply into the poplitaeal space, under cover of the biceps muscle, nearly as low as to the outer condyle, then passes from the space beneath the tendon of the biceps, reaves the superior articular artery, which it accompanies to the front of the joint, and supplies the synovial membrane of the articulation.\nThe inferior external articular, more frequently a branch of the external poplitaeal than of the sciatic, is also a long nerve close to the biceps, and has the same direction as the preceding ; but it extends lower down, passing beneath the tendon of the biceps, and below the condyle of the femur, to the artery of the same name, and it divides on the outer side of the articulation into many branches that extend forwards, perforate the capsules, and supply the synovial membrane.\nThe anterior tibial nerve (interosseous nerve), rather larger than the musculo-cutaneous, passes from beneath the extensor communis digitorum, having previously perforated the deep surface of the peron\u00e6us longus, to the interosseous membrane, which it crosses obliquely downwards, forwards, and inwards ; and a little below the middle of the leg is placed in front of the corresponding artery. It continues to accompany the vessel beneath the annular ligament, passing first to the inside of it, then to the outside, and again to its inside, while behind the annular ligament it divides into an internal and external terminal branch. The nerve in this course is placed first between the tibialis anticus and extensor communis digitorum ; then between the former and the extensor proprius pollicis, and lastly between the extensor pollicis and the extensor communis digitorum. In its course from the leg to the ankle the anterior tibial gives off branches to the different muscles between which it passes ; and also one or two delicate satellite filaments to the anterior tibial vessels.\nThe terminal branches are both rather deeply seated. The internal deep branch, the continuation of the trunk in reference to direction, but not to size, being smaller than the external, passes beneath the dorsal artery of the foot and the tendon of the extensor brevis destined for the great toe, gives filaments to supply the inner part of this muscle, and reaches the first interosseous space, sending a few twigs to the first interosseous muscle. A t the anterior part of this space it communicates with the musculo-cutaneous, and terminates by dividing into two branches destined for the opposed sides of the first and second toes.\n'The external deep branch passes obliquely\n* Ellis\u2019s Demonstrations of Anatomy, p. 675.","page":768},{"file":"p0769.txt","language":"en","ocr_en":"SPINAL\noutwards beneath the exterior brevis, supplies this muscle, and gives off' from its anterior part several delicate filaments, which running close to the tarsus reach the three outer interosseous spaces, and expand in the substance of the interosseous muscles.\nThe musculo-cutaneous nerve (the external peron\u00e6al), commencing its course below and behind the anterior tibial, and running more superficial and external than it, is directed, first obliquely then vertically downwards in the substance of the peronaeus longus ; it is then situated behind the fascia, and at a variable distance from the ankle, generally at the lower third, perforates the fascia, between the extensor communis, and peronaeus tertius. Subcutaneous in the remainder of its extent, it follows the course of the extensor communis, and after running for a greater or less distance parallel to it, divides into an internal and external branch which diverge considerably from each other. This bifurcation is subject to variation, taking place sometimes while the nerve is situated behind the faseia, at others over or very near the annular ligament, and occasionally the two divisions reunite over the annular ligament, and form an irregular oval space between them. While passing deeply between the muscles of the leg this nerve sends two filaments to the peronaeus longus, the inferior of which, given off about the upper fourth of the leg, can be traced running in the subtance of the muscle, to within two or three inches of the ankle. The upper part of the peronaeus brevis also receives a small branch. Shortly after perforating the fascia, the musculo-cutaneous sends off its malleolar branches directed downwards and outwards to the skin over the outer ankle, and anastomosing with cutaneous branches either from the external saph\u00e6nus, or the termination of the peron\u00e6al cutaneous.\nThe internal terminal branch, passing over the annular ligament giving a few branches to it, and some to communicate with the internal saph\u00e6nus and anterior tibial, is directed along the inner border of the foot to the inside of the great toe as far as its extremity. The external branch, having passed over the annular ligament, divides into three branches which are directed along the three outer interosseous spaces, and near their anterior extremities, each branch again subdivides into two filaments supplying the opposed sides of the four outer toes, the most external filament anastomosing with the external saph\u00e6nus. Both terminal branches, in their course from the annular ligament to the toes, send off numerous filaments to the skin on the dorsum of the foot. Such is the usual distribution of the musculo-cutaneous nerve ; but frequently the outer branch does not supply the inner side of the little toe, and occasionally gives filaments only to the opposed sides of the second and third toes. In these instances an extension of the external saph\u00e6nus nerves compensates for the deficiency.\nThe tibial nerve (tibial-sciatic, internal po-plit\u00e6al) much larger than the peron\u00e6al or\nNERVES.\t769\nexternal poplit\u00e6al, is in a direct line with the sciatic nerve. It passes through the centre of the poplit\u00e6al space, rather nearer the semi-membranous than the biceps, then between the two heads of the gastrocnemius to the lower border of the poplit\u00e6us. It perforates the tendinous arch of the sol\u00e6us, reaches the front of that muscle, and passes down the leg between it on the one hand and the deep-seated muscles on the other. At the lower third of the leg it runs from beneath the inner border of the sol\u00e6us, and continues its terminal superficial course, anterior and internal to the tendo Achiliis, as far as the lower extremity of the tibia, and, on a level with the base of the external malleolus, divides into the internal and external plantar. In the upper part of the poplit\u00e6al span, the tibial nerve is superficial and external to the poplit\u00e6al vessels in the middle immediately behind, and at the lower part is placed internal to them. This last relation the nerve holds as far as the lower third of the leg, when it crosses the posterior tibial artery again to. its outer side. It continues very gradually to separate from the vessel ; so that in the interval between the heel and malleolus the nerve is a quarter of an inch nearer the os calcis than the vessel. The branches given off from the tibial are muscular, articular, and cutaneous.\nThe majority of the muscular branches arise from the posterior part of the trunk, and we observe, first, two branches for the two heads of the gastrocnemius entering their anterior surface. The inner branch arises frequently from a trunk common to it and the tibial saph\u00e6nus ; the outer, from a trunk common to it and a large branch for the sol\u00e6us, which enters, usually, the posterior surface of that muscle. When the outer branch is small, one or two others are given off lower-down, to enter its anterior aspect. The small-branch for the plantaris is derived, in the majority of instances, from the trunk of the tibial ; but sometimes from the inferior internal articular nerve.\nThe nei've for the poplit\u00e6us, given off opposite the knee-joint, is directed forwards to the poplit\u00e6al vessels, descends external to them, and terminates at the lower border of the muscle by entering its substance.\nThe nerve to the tibialis posticus comes off from the above, descends along the back of the muscle, gives numerous filaments to it, and terminates by entering below the middle.\nThe nerve for the flexor communis digitorum and the longus pollicis take their origin together somewhat below the preceding ; that for the latter muscle being the larger, and descending to within a short distance of the ankle joint, in company with the fibular artery. The articular branches are three in number, and correspond with the internal and anterior articular branches of the poplit\u00e6al artery.\n\u201c The superior internal articular, very small, arises above the articulation, descends on the outer side of the poplit\u00e6al vessels, passes beneath them, and runs with its artery to the\n3 D","page":769},{"file":"p0770.txt","language":"en","ocr_en":"SPINAL NERVES.\n770\nfront of the femur and inner part of the articulation ; this is the least constant of the branches. The inferior internal articular, the largest of the nerves to the joint, arises rather above the articulation, descends to it, lying external to the vessels, is then directed inwards, beneath the poplit\u00e6al vessels, and meets with the artery of the same name ; it now lies on the poplit\u00e6us, covered by the fascia, passes beneath the internal lateral ligament, winds round the head of the tibia, perforates the capsule, and supplies the synovial membrane. This branch gives, occasionally, some filaments to the posterior part of the articulation. The last articular branch is the posterior or azygos, which is given off opposite the joint, or from the inferior internal nerve : it perforates the posterior ligament, and is distributed to the articulation.\u201d* We have observed this inferior articular nerve give off, occasionally, muscular filaments to the plantaris, and upper part of the poplit\u00e6us.\nThe cutaneous branch is named the tibial sa-phcenus (external saph\u00e6nus\u2014communicating saph\u00e6nus\u2014communicans tibiae), and takes its origin from the back part of the trunk external to the muscular branches. It inclines a little to the outside of the middle of the poplit\u00e6al space, under the fascia, but superficial to the gastrocnemius, along the posterior surface of which it passes till it perforates the fascia at a variable distance from the ankle, and receives the corresponding branch from the peron\u00e6al saph\u00e6nus. It is then directed, under the name of the external saph\u00e6nus, along the outer part of the tendo Achillis to the outer and back part of the external ankle, where it divides into its terminal branches. In the first part of its course it lies to the inside of the external saph\u00e6na vein. Near the lower angle of the poplit\u00e6al span it passes in front of the vein to get to its outside, continues external to it as far as about an inch above the outer ankle, and again passes in front of it to its inside.\nThe tibial saph\u00e6nus gives off no branch till it becomes external saph\u00e6nus, and internal and external cutaneous branches arise from it. The internal supply the outer and back part of the leg : and a superior and inferior calcaneal branch are generally observed. The superior is directed over the tendo Achillis, supplies the skin at the inner and back part of the heel, and communicates with filaments from the external plantar : the inferior passes along the outer border of the tendo Achillis to the skin at the outer and lower part of the heel. The outer cutaneous run downwards and forwards over the tendon of the pero-n\u00e6us longus, as far as the malleolus externus, communicating above with descending filaments of the peron\u00e6al cutaneous ; and below with the malleolar filaments of the musculo cutaneous. Independent of these, cutaneous filaments and a few delicate nerves are given off, which accompany the saph\u00e6na vein.\nThe terminal branches are composed of a series of cutaneous branches to the back part of\n* Ellis\u2019s Demonstrations of Anatomy, p. 676.\nthe ankle, heel, and back part of the outer edge of the foot, and a long nerve, the continuation of the trunk directed along the outer edge of the foot to supply the outer margin of the little toe, communicating previously with the musculo-cutaneous.\nThe termination of the tibial saph\u00e6nus nerve is subject -to considerable variation, both as to size and distribution. It occasionally forms no connection with the peron\u00e6al saph\u00e6nus, and then is very large. When united with the peron\u00e6al saph\u00e6nus, so as to form the external saph\u00e6nus, its terminal branch not un-frequently divides into two ; the one division for the opposed edges of the fourth and fifth toe ; the other for the outer edge of the latter. We have observed the saph\u00e6nus nerve supplying also the opposed edges of the third and fourth toes, whilst the musculo-cutaneous in this instance supplied merely the inner edge of the great toe and the opposed margins of the second and third toes.\nThe tibial nerve, before dividing into the internal and external plantar, gives off, a little above the ankle, an internal calcaneal branch, which in a high division of the nerve comes away from the external plantar. Having supplied the skin at the inner aspect of the heel, it winds beneath the inferior surface of the os calcis, and communicates with the calcaneous branch of the external saph\u00e6nus.\nThe intei'nal plantar nerve, larger than the external and analogous to the median nerve in the hand, passes behind the internal malleolus superficial to and distinct from the tendons of the tibialis posticus, and in front of the posterior tibial vessels. It then runs above the abductor pollicis, and is directed in the intermuscular septum, between it and the flexor brevis digitorum. Having perforated this, it appears between the two muscles, and divides into internal and external branches\nThe internal branch is smaller than the external, passes from without inwards over the tendon of the long flexor of the toe to the inner side of the metatarsal bone, gives filaments to the abductor pollicis, flexor brevis, and the skin, and terminates at the inner side of the toe, supplying in its course filaments to the articulations, and when it reaches the last phalanx, a small cutaneous branch to the dorsum.\nThe external branch divides after a course of about an inch or two. The internal division, as it is directed along the first interosseous space, gives off in its course filaments to the first interosseous and lumbricalis, and at the anterior part of this space divides into two twigs for the opposed sides of the great and second toe. The external division, after a very short course, divides into two branches : the internal crosses obliquely the second interosseous space, gives filaments to the second lumbricalis, and bifurcates at its anterior extremity for the supply of the opposed sides of the second and third toes : the external crosses obliquely to the third interosseous space, and like the preceding divides at its anterior extremity into two twigs for the","page":770},{"file":"p0771.txt","language":"en","ocr_en":"SPLEEN.\t771\nopposed sides of the third and ourth toes, having previously communicated with the external plantar.\nThese different divisions of the internal plantar nerve give off, in their course, filaments to those portions of the cuticle with which they are in relation ; and also small twigs for the metatarso-phalangeal and phalangeal articulations, and muscular branches to the flexor digitorum brevis, over the tendons of which the different divisions of the external portion of the nerve are obliquely and superficially directed.\nThe external plantar nerve, smaller than the internal, is directed forwards and outwards between the musculus accessorius and flexor digitorum brevis, giving filaments to either, and, having reached the inner border of the abductor minimi digiti, which muscle it supplies, divides into a deep and superficial branch.\nThe deep branch passes from between the first and second layer of muscles to place itself between the latter and the third, passing in company with the exterual plantar artery. It describes a curve, the concavity of which looks towards the heel and inner malleolus. Filaments are sent off for the two outer lum-bricales, for the transversalis pedis, the adductor pollicis, the interossei, and the tarsal and metatarsal articulations.\nThe superficial branch passes obliquely forwards and outwards between the flexor brevis digitorum and abductor minimi digiti, to both of which it gives filaments, and soon divides into an external and internal branch.\nThe external branch reaches the outer border of the foot, and terminates at the extremity of the outer aspect of the little toe; giving filaments to the flexor brevis minimi digiti and the articulations. The internal, larger, communicates with the most external division of the internal plantar, and bifurcates at the extremity of the fourth interosseous space, for the supply of the contiguous sides of the fourth and fifth toes. The divisions of the superficial branch of the external plantar nerve, like those of the internal, supply the portions of the integument with which they are in relation, as also the articulations over which they pass.\nThe internal and external plantar nerves are, in reference to size, directly the reverse of the corresponding arteries : the former giving off seven filaments for the supply of the three inner toes, and half of the fourth ; and being analogous in its distribution to the median in the hand : the latter giving off only three filaments for the fifth and half of the fourth toe, and corresponding with the distribution of the termination of the ulnar nerve.\n(Nathaniel Ward.)\nSPLEEN. (Lien seu Splen, Lat. ; SitaV\u00bb Gr. ; die Milz, Germ.; la Rate, Fr.) Normal anatomy. The spleen is a single so-called \u201c vascular gland,\u201d which is attached to the cardiac extremity of the stomach, and appears to possess some intimate connection with the renovation of the blood.\nSituation and form. \u2014 The spleen has a roundish elongated form, or almost the shape of half an egg, and lies in the left hypochondriac region. We recognise on it two surfaces, two borders, and two extremities. The outer surface (superficies externa seu convexa) is completely free and smooth, and often exhibits a more or less deep, long, and oblique incision : it looks outwards, upwards, and backwards ; and is in contact with the left costal portion of the diaphragm, corresponding to the tenth and eleventh ribs. The inner surface (superficies interna seu concava) is directed inwards and forwards; is for the most part slightly concave, and presents, in a prolonged elevation which occupies its middle, a vertical furrow, the fissure for the vessels, or hilus lienalis, which contains many holes and depressions, through which pass the nerves and vessels to and from the spleen. This fissure separates the concave surface into an anterior and larger, and a posterior and smaller portion ; and it is connected by the broad, but short gastro-splenic omentum (ligamentum gastro-lienale), with the fundus of the stomach, to which the remainder of the concave surface is opposed. The upper extremity or head of the spleen (caput Hems'), is the thicker and more obtuse of the two ; it occupies the elevated hinder part of the eighth rib, and is connected by a suspensory ligament (ligamentum phrenico-lienale seu suspensioruni) with the diaphragm. The lower extremity or cauda lienis, is thinner and more pointed, and is directed downwards and forwards. The anterior border (margo anterior) is the thinner and sharper, and is free. The posterior border (margo obtusus) is thick and rounded, and is in contact with the lumbar portion of the diaphragm, and the anterior surface of the left suprarenal capsule. The spleen is thus least moveable, where it is limited by the diaphragm ; but much more so at the site of its attachment to the stomach. But its situation changes with the variable positions of the diaphragm and stomach : thus, on the one hand, it descends and rises in the states of in- and ex-spiration respectively ; and, on the other hand, becomes more superficial or deeper, according as the stomach is empty or full.\nVarieties of the spleen. \u2022\u2014 It is not uncommon to find the anterior border of the spleen, presenting one or more separate deep fissures. Also supplementary spleens (lienculi, seu lienes succenturiati) are now and then observed : according to Rosenm\u00fcller and Giesker, more frequently in the Southern than in the Northern Germans. These are situated in the gastrosplenic ligament, and rarely in the great omentum (Morgagni, Huschke) ; they are red, of the ordinary splenic structure, and of a size which varies from a linseed to a walnut. They are generally one or two in number, less frequently four or seven, and in a misdeveloped foetus have even amounted to twenty-three.\nThe size and weight of the spleen experience great variation, not only in different individuals. but even in one and the same person :\n3n 2","page":771},{"file":"p0772.txt","language":"en","ocr_en":"SPLEEN.\nof this more will be said hereafter. On an average, its length is from 4 to 5J inches * ; its thickness from 1 to 1* inches ; and its breadth, from the anterior to the posterior border, 3 to 4 inches. According to Krause, its cubic contents range between 9| and 15 inches, with an average of 12. Its absolute weight varies from 6 to 15 oz., according to Soemmering ; from 7| to 10\u00a7, according to Krause ; and it has a medium of about 8 oz. According to J. Reid f, between the twentieth and sixtieth years, it ranges from 6 to 10 oz. in the male, and from 3 oz. 13\u00a7 dr. to 9 oz. 10 dr. in the female. Krause also states, that its specific gravity varies from 1.0579 to 1.0625, with an average of 1.0606.\nThe consistence of the spleen is not very great : its parenchyma is soft and doughy, readily yielding to the pressure of the finger. It is not unfrequently torn by mechanical injury during life ; indeed, more easily than any other glandular organ, especially if it be over-distended with blood at the time; but, under the opposite circumstances, it is much less disposed to give way. The colour of the spleen is bluish red, during life greyish violet, and the parenchyma is of a dark dusky red.\nStructure. \u2014 In the spleen we first distinguish the coverings or involucra, and the parenchyma or proper spleen-substance. The first consists of the serous and the fibrous membrane. The latter is composed of a framework of reticulated fibres firmly connected together, constituting the so-called trabecular tissue (trabeculce lienis) ; and, beside this, of the red spleen-substance, the splenic corpuscles, and vessels and nerves, together with sheaths which arise from the fibrous coat.\n1. The serous membrane (tunica serosa) is a part of the peritoneum. It accurately covers the outer surface of the spleen as a smooth membrane, with the exception of its hilus only, where it takes the form of two folds which convey the vessels of the organ, constituting the gastro-splenic ligament, and passing off' to the stomach, where they become continuous with its serous covering. When the ligament uniting the spleen to the diaphragm exists, the membrane is similarly continuous with the peritoneum covering this muscle. The serous membrane is a thin, moderately strong, whitish membrane, which is intimately connected with the fibrous coat ; although in particular places, and especially after previous maceration, the two may be separated from each other. In respect of its microscopical structure, it scarcely differs at all from other parts of the visceral layer of the peritoneum; thus it consists of an outer and single layer of polygonal pavement epithelium, and of an inner layer of white fibrous tissue, in which meshes of fine fibre of yellow tissue are present in no very considerable quantity.\nIn mammalia, e. g. in the sheep, ox, &c.,\n* In this and the following measurements the German inch and line have been retained.\nf London and Edinburgh Monthly Journal, April, 1843.\nas was remarked by Malpighi, the serous membrane is easily separated entire. But in man this is not the case, and hence Haller and others have supposed that only one membrane is present. But microscopical research proves the opinion to be erroneous ; and pathological anatomy confirms this statement, by showing that the outer part of the coat of the spleen shares in the diseases of the peritoneum. In animals numerous vessels are seen in the serous membrane, and a very dense network of stronger and thicker fibres of yellow tissue is present.\n2. The fibrous coat (tunica fibrosa, albuginea, sive propria) is in man a moderately delicate semi-transparent, but firm, membrane, which encloses the parenchyma of the spleen on every side, so as to include it in a kind of sac. Its outer surface is even, and in man is intimately united with the serous covering, with the single exception of the hilus, where the two membranes diverge, and are separated from each other by vessels, nerves, and a loose areolar tissue. The inner surface bounds the parenchyma of the organ, and, with the exception of very numerous solid processes which come off\u201c from it, is limited by the trabecular tissue. At the hilus of the spleen it sinks into the interior of the organ in the shape of tubes (vagince vasorum), which en-sheath the entering and emerging vessels, and are continued on these throughout the whole parenchyma. The fibrous coat, in the human subject, is composed of white fibrous tissue, mixed with elastic or yellow fibres. The former of these, as in other fibrous membranes, consists of bands, which take a parallel course, but do not form distinct bundles ; and the latter are united in a very dense and irregular network. Duvernoy and Stukely have described muscular fibres Fig. 522.\tin this tunic ; but, ac-\ncording to my researches, they certainly are not present in the human subject, although I have found them existing in some of the mammalia, and most visibly in the dog and pig. They are unstriped muscles, the elements of which, the elongated cells or \u201c fibre cells\u201d (fig. 522.) which I have described *, are deposited in considerable quantity amongst the elastic network and white fibrous tissue previously mentioned. Muscular fibre-cell from In addition to these the tunica propria of the two animals I have also spleen of the Dog, mag- found the muscular\nnified 350 diameters. structure in the rar the o, nucleus of the same. stl ucturie \\n tn\u00ae .ca% the ass, and the Dicotyles\n* Zeitschrift f\u00fcr wissenschaftliche Zoologie, von v. Siebold und K\u00f6lliker, Leipzig, bei Engelmann, Jahrgang, 1848, Heft 1.","page":772},{"file":"p0773.txt","language":"en","ocr_en":"SPLEEN.\t773\ntorquatus, while it was absent in the rabbit, horse, ox, hedgehog, guineapig, and bat. The elastic fibres of this tunic are for the most part much stronger than in man.\nTheir peculiar vessels and nerves I have never witnessed.\n3. The trabecular tissue, ([trab\u00e9cules lienis, balks, or joists of the spleen), consists of white, shining, flat or cylindrical fibres, which arise in great numbers from the inner surface of the fibrous coat; and, in smaller quantity, from the exterior surface of the sheaths of the vessels. These are so connected with similar fibres in the interior of the spleen as to constitute a network which extends throughout the whole organ. Between the fibres of this net exist a great number of spaces which are connected with each other, and are occupied by the red spleen-substance and splenic corpuscles ; and which, although very irregular in respect of their form, and, as regards their size, of the most variable dimensions, have yet a considerable resemblance to each other. The older anatomists regarded these spaces as regular and uniform cavities provided with a special membrane. But this last structure nowhere exists, as may be verified in a spleen in which, after short maceration, the pulp has been removed from these spaces by washing. Such a preparation will also afford the best means of studying the mode of connection of the fibres, and in this manner it may be seen that, although they are of very different diameters, yet the finer fibres are not everywhere given off from the thicker ones. This is especially shown by the fact, that fibres of the most different diameters are intimately connected together at all points. Where four, five, or more of these joists meet, there generally occurs a knot of a flattened cylindrical form, which is not unlike that of a nerve-ganglion. Such knots are more frequently found towards the outer surface of the organ, since the cross-beams are more numerous shere than in the interior. In this latter part, namely in the neighbourhood of the great vessels, the numerous ramifications of these tubes themselves serve as points of support to the pulp, and consequently render the joists less necessary.\nThe structure of the trabecular tissue of the human spleen completely corresponds with that of the fibrous tunic, since it consists of white fibrous tissue and the yellow fibres. The former of these two structures exhibits parallel fibrilke, which run without exception in the direction of the long axis of the partition or joist, and rarely unite into individual bundles. The latter consists of somewhat finer and stronger yellow fibres, which anastomose with each other ; their maximum diameter is 1,1000th of a line: the greater number of them lie between the bundles of white fibrous tissue, and are easily recognised bv their irregular course and manifold curves. Many anatomists, with Malpighi, had spoken of muscular fibres in the partitions of the spleen, although none had succeeded in demonstrating them, either with the scalpel or microscope, or chemically. But in 1846 I dis-\ncovered them with the aid of the microscope, in the spleen of the pig.* Here they exist both in the finest and largest of the partitions, but they arq not isolated, being connected with the finer reticulations of the yellow fibres {fig. 523.). In the larger partitions which are\nFig. 523.\nA trabecula from the Spleen of the Pig, magnified 350 diameters, and treated with acetic acid.\na, muscular fibre-cells with a projecting extremity, or not isolated ; b, nuclei of the same ; c, elastic fibres.\nvisible to the naked eye, the muscular and elastic fibres are present in pretty nearly equal quantities, consequently these parts are to be regarded as alike elastic and contractile. But in\u00b0the smallest and microscopic cross-beams the muscular fibres predominate, and often they appear to be even unmixed with elastic fibres. In these parts the quantity of white fibrous tissue is still smaller than that of the yellow ,* indeed, in this animal it is but very sparingly present in the larger partitions. The direction of the fibres above-named is always longitudinal or parallel to the long axis of the joist, never transverse. In similar extent and quantity, and with a like connection to the elastic tissue, I have found muscular fibre in the dog, the ass, the cat, the Dicotyles torquatus, the sheep, rabbit, horse, hedgehog, guineapig, and bat. In the ox, on the contrary, it exists only in the finer and microscopic partitions, where it is present in very considerable quantity and in remarkable distinctness. The remainder of the trabecular tissue consists only of yellow fibre in union\n* Mittheilungen der naturforschenden Gesell schaff in Zurich, 1847, S. 120.","page":773},{"file":"p0774.txt","language":"en","ocr_en":"774\nSPLEEN.\nwith some white fibrous tissue. As to the lower vertebrata, I have examined a great number of them with respect to this muscular structure, and have found that the smallness of the spleen in many of them offers a great obstacle to observation ; yet I believe I have verified that the spleens of the pigeon, sparrow, blindworm, tench (tinea chrysitis), and trout, contain muscular fibres. So, also, my friend Professor Ecker, of Basle, has orally communicated to me that he has found very distinct muscular fibre in the spleens of the ray and shark.\nAll these muscles are, like those of the fibrous coat, unstriped ; their elements consist of elongated shortish fibres, each possessing a long nucleus. (Fig. 523. a, Fig. 524.) In the thicker partitions there are what I call \u201c muscular fibre-cells,\u201d either stiff, pale, flat, from 4 to 6.1000ths of a line broad, and 2 to3.100ths long, or more cylindrical, darker, spindle-shaped, and undulating, varying from 2 to 5.100ths of a line in length, and 3 to 4.1000ths in breadth. In both cases they have long, neat, small, staff-shaped, nuclei. In the finer partitions, on the contrary, appear many shorter and more spindle-shaped fibre-cells ; their nuclei are elliptical or even spherical, and they often project laterally from the fibres, so as sometimes to render these muscular elements scarcely distinguishable from the spindle-shaped epithelial cells of the splenic arteries.\nThe muscular elements rig. 524. just described are seen in the best and plainest manner in the pig and dog ; but they are also readily verified in the horse, ox, ass, sheep, and cat, in all of which they may frequently be isolated. In the other mammals previously named, and in the rest of the vertebrata, they are less easily recognised, and are scarcely susceptible of isolation ; but they can always be partially uncovered, and in any case may be demon-\nstrated by the applica-Muscular fibre-cells from \u2022 f ^\t:j\nthe trabecula of the Pig,\t,0t ,.aC.etlC auCK.1\u2019\nmagnified350diameters, 'vhich displays their\n1, without acetic acid; characteristic nm lei.\n2, with acetic acid; a, As regards the hu-nucleus.\tman subject, I find that\nin the partitions which are visible by the naked eye, no trace of unstriped muscular fibre is present; and they probably consist entirely of yellow and white fibrous tissue. In the finer partitions, on the contrary, elements occur to which one may perchance ascribe a muscular character. They are the same short fibres of a peculiar kind (fig. 525. 1.), which GUnsburg* has\n* Pathologische Gewebelehre, Band. i. S. 81.\nFig. 525.\nPeculiar structures from the human spleen, magnified 350 diameters.\n1, spindle-shaped fibres with a nucleus ; 2, a cell, which contains such a fibre; 3, a similar cell, without a fibre.\nerroneously regarded as epithelial cells of the splenic veins ; otherwise they have hitherto remained altogether unnoticed. They are characterised by their roundish or elongated oval nucleus, which is laterally disposed, and often occupies a pedunculated process ; by their homogeneous texture ; by their easy undulatory or serpentine outline ; and, finally, by their size, which offers a breadth of 15 to 25-1000ths, and a length of 2 to 3-100ths of a line. The round nuclei of these fibre-cells, even at first sight, somewhat militate against their muscular import ; but it must be recollected, that in the mammals named it has been previously stated that the muscular fibre-cells, which occur in the smallest partitions, deviate considerably from the characteristic fibres, and greatly resemble the structures now described in men. On this account, and from the further fact, that the above mentioned human fibre-cells, in moderately fresh spleens, seem to occupy the smallest partitions, just as the muscular fibres in animals ; while in later periods after death, or in decomposed spleens, they can only be found isolated, with the parenchyma cells, in the red pulp of the spleen, I formerly considered it not too hazardous to regard them as muscular fibre-cells. But more recently I have made some observations which have again thrown me into complete uncertainty in respect of the import of these questionable structures. Thus 1 believe myself to have verified, that these fibres occur in the human subject rolled together in a kind of spherical cell (fig. 525.2,) of 5 to 7-1000ths of a line in diameter ; and that, on tearing up this structure they become free, and extend themselves.. But, since this fact in no way harmonizes with the nature of muscular fibre-cells, and is besides altogether obscure and incomprehensible to me, I hesitate to express at once an opinion concerning the above-mentioned structures in the human spleen, but am desirous of calling the attention of inquirers to this peculiar arrangement, which, on account of its constancy and frequency, is very interesting","page":774},{"file":"p0775.txt","language":"en","ocr_en":"SPLEEN.\t775\n4. The splenic corpuscles or Malpighian corpuscles of the spleen (vesicul\u00e6 seuglandules lienis, s. corpuscula Malpighn) are whitish spherical corpuscles, which are imbedded in the red spleen substance of certain animals, and are connected with the smallest arteries. In the dead bodies of men, in the state in which they are generally subjected to examination in hospitals, these corpuscles are very seldom seen. On this account, some of the earlier observers, as Rudolphi, Heusinger, Andral, and others, and more recently Gluge * * * \u00a7 and Oesterlen j-, have regarded them as not constant structures, or even as products of disease; or have considered them as J. Muller formerly did J, to be altogether distinct from the splenic corpuscles of the Ruminantia. But this view is erroneous, and since Giesker\u00a7, Krause ||, and BischoffH, who described the splenic corpuscles of the human subject, and showed their correspondence with those of the mammalia ; and since the revocation by Muller of his earlier opinion **, all observers are tolerably agreed, that although the corpuscles in question are often deficient in the human subject, yet they are not the less to be regarded as normal structures, which are invariably present in the healthy subject.\nThe frequent deficiency of the splenic corpuscles is explained by many circumstances. Most of the observations of them concern human individuals, in whom a long abstinence from food has preceded death. In such cases, as Henle has well remarked fj-, the apparent absence of the corpuscles is easily explicable, since their size is notoriously regulated by the quantity of ingesta. So, also, great number of the human spleens which come under our notice are diseased; either softened, distended with blood, and soaked through with extravasations, or enlarged, hardened, atrophied, or already half decomposed and putrified. Finally, the human spleen corpuscles are very delicate, and easily destroyed. As to the frequency of their occurrence in diseased subjects, we are supplied with accurate data by v. Hessling, who has given the results of 960 dissections. Of the whole number just mentioned, Malpighian corpuscles were only present in 116, or in about every eighth individual. He also adds the following numerical statement respecting the different ages of life. In the first and second year of life the corpuscles were present in every second subject; from the second to the tenth year, in every third subject ; from the tenth to the fortieth year, in every sixteenth ; from the fortieth year to old age, in every thirty-second. These numbers are in general correct, and are readily explicable when we recollect that diseases of\n* H\u00e4ser\u2019s Archiv, f\u00fcr die gesammte Medicin, 1841, SS. 83. 88.\nf Beitrage zur Physiologie des gesunden, und kranken Organismus, Jena, 1843, S. 48.\nJ Muller\u2019s Archiv, 1824, S. 80.\n\u00a7 Splenologie, S. 159.\n|1 Anatomie, Band. i. S. 520.\nM\u00fcller\u2019s Archiv, 1838, S. 500.\n** Physiologie, Aufl. 4. Band. i. S. 466.\nff Algemeine Anatomie, S. 1000.\nthe spleen are more numerous as age advances. But the results of my own observations coincide with those of Oesterlen, in representing the number of cases in which corpuscles are detected as greater than that above mentioned. This difference may be ascribed to the difficulties which often prevent the recognition of the dwindled spleen corpuscles; thus in many cases where the first view has afforded no signs of their presence, the application of soda, or the washing of the pulp, has brought them into view.\nOn the other hand, it is absolutely certain that, in many spleens, they disappear without leaving any traces, and cannot be made visible by any method of treatment. In the bodies of healthy individuals which are examined while fresh, they may always be detected ; at least, there are very numerous observations extant in which they have been found after accidental deaths, executions, suicides, &c. ; and to these cases I myself am enabled to add two. So, also, I have found them in a great majority of the bodies of children which I have examined ; and here they are both very distinct and numerous, so as not to offer any visible difference, in these respects, from those of the Ruminantia.\nThe size of the Malpighian corpuscles experiences many variations both in men and animals, even apart from the effects of disease : they measure from one-tenth to one-third of a line; on an average, about one-sixth. Their size has hitherto been somewhat too highly estimated ; and chiefly on this account, that sufficient preliminary care has not been taken to isolate them from the surrounding parts : when this is done it will be found, that they are not so large as appears from viewing them on a section of the spleen ; and that, in many cases, they measure less than the given bulk. The fluctuations in their size depend not merely upon the differences of individuals, but obtain in one and the same animal : in this latter case, they appear mainly to be regulated by the condition of the chylopoietic viscera; although accurate data, as to these points in the human subject, are altogether deficient.\nIt is also possible, as Oesterlen has supposed, that these corpuscles experience a certain course of development ; and that, in many cases, the very small corpuscles are very young and undeveloped ones : but, hitherto, I have not been able to observe facts importing the certain existence of a continual development of the Malpighian corpuscles in the adult animal ; nevertheless, I cannot avoid mentioning that, like Oesterlen, I have seen in the spleens of animals little heaps (from 2 to 4-100ths line in size) of cells, which have no distinct cell walls, and which, possibly, have some relation to the formation of the splenic corpuscles. It seems quite certain that the spleen corpuscles are not developed from separate cells of the spleen pulp ; although this view has lately been brought forward in a singular manner by Heinrich.*\n* Die Krankheiten der Milz, 1847, S. 15.\n3 D 4","page":775},{"file":"p0776.txt","language":"en","ocr_en":"776\tSPLEEN.\nTiie Malpighian corpuscles are imbedded in the red spleen substance, and, with the exception of one point, where they are attached to arterial twigs, they are everywhere surrounded by this substance. They are coning. 526.\nA small arterial trunk with Malpighian corpuscles, on a somewhat larger artery. From the spleen of the Pig. Magnified 10 diameters.\na, the artery ; h, the sheath of the same ; c, Malpighian corpuscles ; d, pencils or tufts of arteries.\nnected to the small arteries and their twigs by short peduncles, like the berries of a bunch of grapes ; and, in such wise, that a small arterial trunk of from 2 to 4-100ths line, with its ramifications, supports 5 to 10 corpuscles. (Fig. 526.) The peduncles of the corpuscles are almost always small arteries, which pass to be distributed to them ; but in less frequent instances, they are constituted by short processes of the arterial sheaths, which are continuous with the membranous wall of the corpuscle. In this manner the majority of the\nFig. 527.\nA Malpighian corpuscle from the spleen of the Ox in connection ipith a small artery, magnified 150 diameters.\na, wall of the Malpighian corpuscle ; b, contents of the same ; c, coat of the artery ; d, sheath of the same.\ncorpuscles are essentially devoid of a peduncle, and sit immediately on the arteries at their\npoints of bifurcation, or at then* sides, (Figs. 527, 258.) This relation, which also obtains\nFig. 528.\nMalpighian corpuscle from the spleen of the Pig in connection with an artery from which a branch passes to the corpuscle. Treated with soda, and magnified 250 diameters.\na, wall of the corpuscle ; b, elastic fibres in the same ; c, sheath of the artery ; d, dissolved middle tunic of the artery ; e, elastic inner coat, in animals, formerly appeared to J. M\u00fcller as indicating the fact that the splenic corpuscles were hollow excrescences of the vessel-walls, or were imbedded in these latter. But if by this be understood, what Muller\u2019s plates and description imply, that the sheaths of the vessels, in their whole thickness, with all their elements, are continued to form the corpuscles, then it is certainly incorrect : for in some animals I have seen that, from the rich network of elastic fibres and muscular structure of these sheaths, little or nothing passes to the corpuscles : and I have generally found the membrane of the corpuscle very delicate. It is, however, quite conformable to truth, to state that this membrane has a direct continuity with the arterial sheaths. (Fig. 527, 528.)\nThe corpuscles do not possess any connection with the trabecular network, still less that which Gerlach has lately attributed to them : viz. that they serve as points of support to the elastic fibres of the partitions ; a belief which is altogether baseless.\nIt is difficult to say any thing definite respecting the number of the splenic corpuscles. Hessling believes that, in some cases, they constitute from one-fifth to one-sixth of the whole splenic mass ; and this seems to me no overstatement, if we substitute the expression \u201c spleen-pulp \u201d for \u201c spleen-mass.\u201d At least, I have found, that their quantity is very considerable; and that in some instances, when they are rather turgescent, the whole pulp appears as if besprinkled with white. They stand so thickly together, that in many places they touch each other\u2019s sides ; and in others are only separated from each other by narrow interspaces, which in the least favourable circumstances are about one to two lines in size. I believe that the estimate, that one and a half to two lines of spleen-pulp con-","page":776},{"file":"p0777.txt","language":"en","ocr_en":"SPLEEN.\n777\ntains one Malpighian corpuscle, is rather too little than too large.\nAs regards the lower animals,it would follow from my researches, that the Malpighian corpuscles occur in Mammalia in precisely the same way as in Man ; at least, in more than twenty genera which I have examined, I have never found them to be absent. It has long been known that they are very distinct in pigs, sheep, oxen, goats, and so also in guinea pigs, hedgehogs, and bats, See., in whom they are rather larger and more resisting than in Man ; and although in the dog, cat, and rabbit, they are somewhat smaller and more covered by the pulp, yet they are nevertheless very distinct. As to Birch, Bardeleben seems to have recognised the Malpighian corpuscles in swallows, pigeons, and geese ; while I have been able to verify their existence in sparrows, although they are not particularly distinct. So also Ecker briefly states, that he has seen them in birds; and Oesterlen mentions their occurrence in the fowl, pigeon, and in many of the Raptores. Amongst the Reptilia, J. Muller has detected them in the Chelonia ; while I have seen them very distinctly in the anguis fragilis, in whom the corpuscles were surrounded by a beautiful network of capillaries. Amongst the naked Amphibia, Oesterlen states himself to have seen them here and there in toads and frogs ; but in direct opposition to this, I have found no trace of them. Just as little have I been able to detect them in Fishes, although 1 have examined many of the fresh-water genera with this especial purpose. And thus the conjecture of M\u00fcller*, \u2014 that they exist in all the verte-brata, although in none so distinct or so easy of observation as in the vegetable-eating mammals \u2014must be considered as incorrect : a eirumstance which is not without considerable interest in the determination of their import.\nOn inquiry into the more minute structure of the Malpighian corpuscles, it is exceedingly necessary to regard, not only their appearances in Man, but also in the lower animals. Each Malpighian corpuscle possesses a membrane and contents, and therefore is not a solid corpuscle, but rather a vesicle. The membrane which Malpighi beheld, was minutely described for the first time by Miiller and Giesker. According to the first of these observers it is, as previously mentioned, a process of the common sheath of the vessels, which either immediately continues as a vesicular swelling of the same, or is previously produced into a peduncle. Giesker rejects this view, at least as regards the human subject, and describes in each corpuscle a peculiar, independent, and tolerably strong membrane, which seems to have no connection with the sheaths of the vessels, but receives an additional thin outer covering of white fibrous tissue, in which the vessels of the corpuscle ramify, and to which they frequently impart their own red colour. The ma-\njority of later observers have unconditionally adopted one or the other of these views ; only a few of them, as J. Simon, Henle, Ecker, and Oesterlen, having taken the trouble of substantiating their truth by original inquiry. Henle, Oesterlen, and J. Simon, deny the existence of a special membrane. The first of these observers finds that the wall of the corpuscles is constituted solely of granules, under which appear to be comprised structures resembling the morphous part of the contents ; while fine bundles of white fibrous tissue unite on their outer surface. Oesterlen and J. Simon likewise deny the peculiar membrane (limitary membrane), an absence which the latter associates with the capacity of the corpuscles to fill themselves out from the capillary vessels. So also Bardeleben describes a membrane very indistinctly.\nOn the other hand, Ecker * has assured himself of the presence of a membrane in mammals and birds. By the application of potash, the masses of granules which seem to constitute the wall of the corpuscle were dissolved ; and he then not only saw the ramifications of the arteries on the Malpighian corpuscle with great distinctness, but he also recognised that this possesses a distinct membranous wall, in which a network of exceedingly fine and well-defined stripes could be detected. Although these stripes are actual fibres, yet, according to Ecker, they everywhere cover a structureless gland-membrane, for the wall of the vesicle is never interrupted in the structureless intervals between these fibres ; indeed it is possible that the latter are themselves but folds of a structureless membrane. Amongst the most recent authors, Arnold f and Huschke \\ accept Giesker\u2019s view, and Dr. Gerlach \u00a7 repeats Ecker\u2019s decision. As to myself, in the first place, l regard it as an incontrovertible fact, that the Malpighian corpuscles possess a special membrane. If one of the vesicles be isolated, and sufficiently separated from the surrounding tissues, it may be seen without any further preparation, especially with a slight pressure (fig. 527.) ; and it becomes particularly distinct if a little dilute soda or potash be applied (fig. 528.). These reagents dissolve all the surrounding parts of the pulp, with the exception of the vessels, and thus leave the membrane of the vesicle, although somewhat altered, yet quite entire. Concerning the nature of this membrane, I have verified the following: it is colourless, transparent, about 1 to 2-1000ths of a line in thickness, has everywhere two contours, and here and there it exhibits concentric lines. Its structure so far corresponds with that of the sheaths of the vessels with which it is continuous, that it contains at least white fibrous tissue and elastic fibres ; but the unstriped muscular fibres which oc-\n* Der feinere Bau der Nebennieren, 1846, S. 10.\nf Anatomie, ii. S. 123.\nj Eingeweidelehre, S. 178.\n\u00a7 Zeitschrift f\u00fcr Kationelle Medicin, Bd. v\u00ee\u00ee. S. 77.\nPhysiologie, i. S. 486.","page":777},{"file":"p0778.txt","language":"en","ocr_en":"778\nSPLEEN.\ncur in these sheaths in many animals, are altogether absent from the membrane of the Malpighian corpuscle ; and the latter must especially be noticed as being much more delicate than the sheaths of the arteries on which the corpuscles sit. The white fibrous tissue, which Ecker regarded as a continuous membrane, in consequence of having seen it when changed by the action of potash, is in precisely the same condition as in the partitions and sheaths of the vessels, and forms by far the greatest part of the coat of the corpuscles ; while the elastic tissue (the stripes of a doubtful nature which Ecker saw) appears to constitute only a more or less extensive network of pale, so-called nuclear fibres (kernfasern) (y%. 528. b). So that the membrane of the Malpighian corpuscles would thus appear to be only a modified portion of the vascular sheath,\u2014 a view which most approximates to that enunciated by J. M\u00fcller. An outer coat, of which Giesker speaks, has never been plainly verified by me as a special membrane connected with the preceding ; but it seems to me more probable, that the corpuscles are always immediately surrounded by the cells and vessels of the pulp. Certainly these vessels are often connected together by an indistinct fibrous or membranous substance, but this is especially present in the pulp, and is nothing else than the termination of the sheath of the vessels. The preceding remarks especially apply to the Malpighian corpuscles of the higher brute mammalia. As to those of man, although they are much more difficult to examine, yet I have satisfied myself in the most positive manner that they correspond with those of the brute mammalia in all essential points. This is easiest and best seen in the spleens of children. The structure of these is exactly that seen in animals, only the coat is more delicate, so that it is extremely difficult to isolate a single corpuscle entire, and the contents are expelled by the slightest pressure. In the wall is seen the same network of elastic fibres as in animals, and this renders it possible even to recognise those which are burst. Extremely fine capillaries of 3-1000tbs of a line in diameter may frequently be seen around the corpuscles ; but the latter are just as little enveloped in a second membrane as in animals.\nThe Malpighian corpuscles do not possess in their interior an epithelium and separated contents like the glands, but they are densely filled with a semifluid, greyish white, cohesive mass (fg. 527. b). This contains, together with a small quantity of a clear fluid, a large quantity of morphous particles, which have been very differently described by different observers. According to J. M\u00fcller they very much resemble the corpuscles of the spleen-pulp, and have a general likeness to the blood discs, but are irregularly spherical. BischofF regards them as altogether corresponding with those of the chyle, both in appearance, size, and behaviour with water and acetic acid. According to Henle, they resemble those of the spleen-pulp and those of the\nthymus and thyroid body ; and he so describes them, that it would appear he recognised nuclei and a small proportion of cells. Oesterlen describes them as nuclei resembling the elements of the pulp. Hessling, Huschke, and Nasse* agree with BischofF respecting the similarity of the elements in question to the lymph and chyle corpuscles. The latter of these authorities finds those of the rabbit to be 2\u20143-1000ths of a line in diameter, while Hessling certifies to their size in men as from 2\u20145|-1000ths, and describes their surfaces as possessing a mulberry-like appearance, and their contents as partly minute granules, partly separate nuclei. J. Simon found that the corpuscles in question never attained a development into cells. Remakf describes them as consisting \u2014 partly of large transparent cells, with an interior containing a single lateral, or double and clear nucleus \u2014 partly of small, dark-bordered vesicles, closely surrounded by a delicate pale membrane, and occupied by a dark central nucleus. The first, according to him, resemble the larger, the last the smaller lymph corpuscles. Finally, Gerlach finds in the Malpighian corpuscles the nuclei of cells, and, in equal quantity, cells of different sizes, with one, two, or three nuclei, as well as blood corpuscles, with all those forms of granule-cells which I shall hereafter describe as developed in the spleen-pulp from the effused blood.\nThese are the most important accounts given by others. As the result of my own researches, I must, firstly, corroborate J. M\u00fcller, who explains the elements of the contents of the Malpighian corpuscles and spleen-pulp as similar structures. Also, I can add with BischofF, that they often resemble the chyle corpuscles ; yet I am not disposed to lay any weight upon this correspondence. Furthermore, I consider it fully made out that jGer-lach\u2019s view, according to which blood corpuscles, and cells which include blood corpuscles, are a constant constituent of the Malpighian corpuscles, is altogether erroneous. They are not even frequent occurrences, for in many animals I have not found them at all ; and when they occurred \u2014 as, for instance, in oxen\u2014they were mostly found in scattered vesicles, and, further, were in such small quantity, that they had no influence on their colour. And very often blood corpuscles and their metamorphoses appeared to occupy the vesicles, where a more careful examination showed that they were only in contact with their outer surface. The degree of accuracy to which Gerlach\u2019s assertion may lay claim is best shown by the fact, that he altogether denies the existence of these granule-cells (which are produced from the effused blood) in the spleen-pulp ; while it is here, as well in these as in animals which possess no proper spleen vesicles, that they occur in\n* Handw\u00f6rterbuch der Physiologie, von R. Wagner, ii. S. 387.\nj- Diagnostische und Pathogenetische Untersuchungen : Berlin, 1845.","page":778},{"file":"p0779.txt","language":"en","ocr_en":"SPLEEN.\n779\nthe greatest quantity, and are most easily seen.\nThe constant and essential elements of the splenic vesicles are cells, with a single nucleus of a spherical shape, and from 3 to 5-1000ths of a line in diameter: besides these, free nuclei, and larger cells of 6-1000-ths of a line in diameter, and with one or two nuclei, also occur (fig. 529.). The cells are in general pale and faintly granular ; their nuclei are from 16 to 25-10000ths of a line in size, spherical, apparently homogeneous, and with a rather dark margin ; or frequently vesicular, with a more or less distinct nucleolus and other granules. It is not infrequent to see\nFig. 529.\nElements of the Malpighian corpuscles of the Ox, magnified 350 diameters.\na, smaller cells ; b, larger cells ; c, free nuclei.\nsingle cells provided with dark fatty granules, and in particular instances blood discs are present, either changed or unchanged, free or included in cells. The free nuclei are of the same size as those contained in cells, and are also, in other respects, quite similar to them. In the ordinary method of examining the Malpighian corpuscles, the quantity of them nuclei seems larger than it really is, since many of the cells burst, and allow their nucleus to escape. Yet it is very remarkable that their number is very variable in the most cautious examination, a fact which appears to me partly to account for the very different statements of different observers. I-n many cases it has happened to me to find only a few free nuclei, often none at all, while in other instances they constitute a half or more of the elements of the corpuscles. This fact, taken together with the often very different size of the cells present, seems to prove that a continuous process of cell-growth exists in the Malpighian corpuscles ; in such wise, that new nuclei and cells continually arise, and old cells perish. But hereof more will be said in speaking of the pulp, in which the same process obtains.\nIf, after these remarks, we take a glance at the import of the Malpighian corpuscles, we shall be compelled especially to ask ourselves, first, whether they are the beginnings of the lymphatics, or in any other way connected with them ? and, secondly, whether they have the import of glandular vesicles ? A connection of the Malpighian corpuscles with the lymphatics was a belief of many anatomists in earlier times, and in our own days has been recently upheld by Giesker, Huschke, Gerlach, and Poelmann. The acceptors of such a theory rest mainly on conjecture, but partially also on facts. Amongst the latter, there may be mentioned \u2014 1. The cor-\nrespondence of the cells in the Malpighian corpuscles with the lymph corpuscles. But we must remember that cells which correspond with the lymph corpuscles occur in many other situations where no such connection with the lymphatics can be imagined, as in the spleen-pulp itself, in the pancreas, in the salivary glands, the glands of mucous membrane, the thymus, thyroid, &c.\t2. Huschke\nadduces the similarity of the spleen vesicles with the whitish granules of the lymphatic glands, which are dilatations of the lymphatic vessels themselves. Against this it need only be objected, that this latter is a pure fiction of Huschke\u2019s, and that even were it as he states, no conclusion concerning the nature of the Malpighian corpuscles could fairly be deduced from it. I have yet further to mention, that, according to an oral communication of Ecker which was made to me many years ago, and recently repeated, concerning the splenic vesicles of the mammalia, processes and pedicles exist which are neither bloodvessels nor partitions, and, therefore, may be lymphatics,\u2014a view with which Poelmann\u2019s and Gerlach\u2019s recent statements are somewhat in unison. The former of these two* says that he followed the thoracic duct even to the Malpighian corpuscles, with which it became connected ; but he does not specify more exactly the nature of this connection. The latter says that it has often seemed to him as if the neighbouring Malpighian corpuscles communicate with each other through special tubes ; that he has been led to this belief by the circumstance that when the vesicles are compressed, their contents are expelled in definite directions, which a closer examination shows to be canals, the coats of which tolerably resemble in texture those of the Malpighian corpuscle ; and that it is thence clear that the corpuscles communicate with a system of tubes which can scarcely be imagined to be any thing else than the lymphatics. And thus, if the Malpighian corpuscles are dilatations of the lymphatics, they may possibly be commenced as simple varicose swellings, or, what is more probable, as lateral productions of these vessels. I acknowledge that I am unable to verify this fact last adduced, or to subscribe to this connection of the Malpighian corpuscles with the lymphatics. In my researches I have given an attention to this point conformable to its great importance ; and although I have not seen the commencement of the lymphatics in the spleen, yet I have so far come to a positive conclusion, that I am convinced of the complete closure of the Malpighian corpuscles. What Gerlach states of the tubes into which the contents of the corpuscles are forced, is altogether erroneous; such tubes nowhere exist. Gerlach appears to have been misled to this opinion by the fact, that when a corpuscle is burst by pressure, the contents rush out at several points,\n* Annales et Bulletin de la Soci\u00e9t\u00e9 de M\u00e9dicine de Gand, 1846, p. 267.","page":779},{"file":"p0780.txt","language":"en","ocr_en":"780\nSPLEEN.\nand are then effused in the shape of long and small streaks in the surrounding tissues. If the commencements of such a streak were not observed, it might easily be regarded, from its always taking a radiating course fronr the Malpighian corpuscle to which it is united, as a canal communicating with the same, especially when a longer pressure applied to the corpuscles has elongated these stripes by continually forcing out the contents. The processes which Ecker has described on the Malpighian corpuscles, and which are not bloodvessels, probably belong to the same category as the artificial products mentioned above ; or, if this is not the case, it is possible that they are small trunks of nerves, which are frequently present in the neighbourhood of Malpighian corpuscles, and which, from reasons that will be hereafter mentioned, are exceedingly difficult to recognise as being what they really are. I therefore maintain, quite plainly and definitely, that the Malpighian corpuscles are closed capsules, and stand in no connection at all with the lymphatics.\nIf this be so \u2014 and the structure of the Malpighian corpuscles, which altogether differs from that of vessels, corroborates the fact \u2014 it is next demanded may not the Malpighian corpuscles be glands? If by \u201cglands\u201d be meant the word in its ordinary sense, I answer with a decided \u201cno for these altogether differ from the known simple shut glandular sacs of the ovary, thyroid, thymus, and supra-renal capsules, and possess neither a structureless membrana propria (limitary membrane, or basement membrane) nor an epithelium. On the contrary, in my opinion, they correspond with the spaces filled with cells in the lymphatic glands, and with the sacs of the glandul\u00e6 solitari\u00e6 and agminat\u00e6 of the intestine. Here and there hollow spaces exist, which possess a covering of white fibrous tissue, are completely inclosed, and contain in their interior no trace of epithelium, but only a coherent mass of nuclei and cells, together with some fluid ; we might call these \u201c vesicular glands,\u201d recollecting at the same time that they possess the function of the real shut glandular vesicles, although their anatomy essentially differs. Although the discussion of the former question does not belong to this part, yet I will add, that, in reality, there is much to indicate that the structures in question constitute a kind of shut glandular vesicle ; and that, consequently, there is nothing to prevent their being regarded as glandular vesicles.\n5. The red spleen substance, the spleen-pulp, the parenchyma of the spleen (substantia ru\u2019ra, pulposa, parenchyma lienis), is a soft reddish mass, which fills up all the interstices between the larger partitions and the stronger vessels, and on section of the organ is easily scraped off or squeezed out. It consists essentially of three constituents ; which are, fine bloodvessels, parenchyma cells of the spleen, and small partitions or fibres. To these constituents is so frequently added, both in man and animals, extravasated or\ncoagulated blood in various metamorphoses, that one is almost forced to designate it a normal constituent. According to the predominance or diminution of the latter ingredient, or according to the greater or lesser distention of the bloodvessels themselves, the spleen-pulp appears sometimes altogether of the colour of the blood, at others of a clearish red, with a greater or lesser tendency towards whiteness.\nThe following remarks apply to the microscopic appearances of the constituents of the pulp, the vessels only excepted, which will be described hereafter. The fibres of the pulp are of two kinds. The one kind, which may be named \u201c small or microscopic partitions \u201d (\u201c microscopische balkchen \u201d), are quite analogous to those larger partitions (\u201c balken\u201d) which are visible to the naked eye ; they are also of the same structure, except that in the lower animals they often contain more muscular fibres than the latter. Their diameter is variable, from 5 to 10-1000ths of a line ; their frequency and quantity also vary in different situations, and amongst different creatures. In the human subject I find them to be fewer and broader than amongst other mammalia, and exactly like the larger partitions in structure ; while in the ox, sheep, &c., they occur frequently, are more delicate, and are remarkable by their purely muscular structure. The other fibres of the pulp are evidently processes from the sheaths of the larger vessels ; they greatly predominate in quantity, and appear chiefly in the form of delicate membranes of an indistinctly fibrous structure, and without any mixture of elastic fibres, which seem to connect the capillaries to each other. Whether they take the form of small partitions \u2014 in which case they could not be distinguished from the small trabeculce \u2014 is at present undecided. In animals, these membranes are also present on the veins ; but of this more will be said hereafter, in speaking of the vessels.\nThe cells of the spleen-pulp, which I shall call \u201c parenchyma-cells of the spleen,\u201d have been described by J. Midler as similar to those of the Malpighian corpuscles ; and, as was previously stated, this view has been followed by the majority of writers ; as by Henle, Bischoff, Huschke, Remak, and others. Only Von Hessling and Gerlach are of another opinion. According to the former, the globules of the spleen-tissue are distinguished by their dark colour, and by their being mingled wdth spindle-shaped cells. Gerlach finds that cells with nuclei are rare in the spleen-pulp ; while, on the contrary, he considers them to be frequent in the Malpighian corpuscles. As to myself, I have already expressed my concurrence with the view taken by Midler, and may therefore forbear to enter further upon this point ; nevertheless, it is necessary to remark that the parenchyma-cells exhibit some additional peculiarities, which ought not to be passed over without notice. A considerable portion of these cells completely correspond","page":780},{"file":"p0781.txt","language":"en","ocr_en":"SPLEEN.\t78]\nwith the cells of the spleen vesicles ; the characteristic appearances of which are their\nFig. 530.\nParenchyma-cells from, the spleen of the Ox, magnified 350 diameters.\na, Smaller cells ; h, cells of medium size ; c, free nuclei ; d, largest cells.\nroundness, their size \u2014 from 3 to 5-1000ths of a line \u2014 their paleness, and their dark nucleus (fig. 530. \u00a3). On the other hand, smaller and larger corpuscles also occur in the spleen-pulp, which are never met with in the Malpighian corpuscles. The former are small round corpuscles, somewhat larger than blood globules. They are seen in one of two states : either they exhibit a membrane and nucleus inseparable from each other, and thus, apart from their colour and somewhat lighter outline, resemble blood globules ; or they are free nuclei, in which no nucleoli are visible. But only a few of these are free nuclei, for by the application of saliva or a little water a membrane starts into view, either completely enclosing them, or limited to one side (fig. 530. a). The nuclei, which thus appear as something separate from the membrane, have always the dark appearance of those cells the two parts of which are inseparable from each other ; so that the appearance of these latter would seem chiefly dependent on the nucleus. With these small and quasi-developing cells, one also meets with free nuclei ; and careful manipulation of the preparation shows these to be in general more numerous than in the Malpighian corpuscles {fig. 530. c). The larger named corpuscles are partly pale cells of 7-1000ths of a line in size, with one or two nuclei^; or granule-cells of 4 to 6-1000thsof a line, and which may be described as \u201c the colourless granule-cells\u201d {fig. 530. d) : both of these are more frequent than in the Malpighian corpuscles. The spindle-shaped or fusiform cells which Hessling mentions do not belong to the normal constituents of the spleen-pulp, and are nothing else than epithelium cells of the splenic arteries {fig- 534. b), which in macerated specimens of the human spleen, and in preparations where the vessels have been cut through, easily get into the pulp, and give rise to the delusive appearances of the so-called fusiform cells. The comparative examination of this part of the spleens of many animals confirms what has been already stated of the elements of the Malpighian corpuscles ; namely, the elements of the pulp vary greatly, since sometimes the nuclei, sometimes the smaller cells, sometimes the greater cells, predominate. And in this, as in the former case, I conclude therefrom that a continuous process of cell growth obtains in the spleen, by which new cells are\nformed around nuclei, and old ones disappear.\nThe quantity of parenchyma-cells of different kind and shape, and of free nuclei which must be reckoned with these, is a very considerable one ; so much so, as to constitute nearly one half of the whole red spleen substance. These do not lie collected in large heaps, but constitute small irregular groups of different size, which occupy the interspaces formed by the partitions of all sizes, the vessels, and the Malpighian corpuscles. The best method of representing this disposition is to regard each part of the pulp, which is included in a large mesh by trabecul\u00e6 visible to the naked eye, as constituting in a small form what the spleen itself is in a larger. The microscopic partitions and fibres and the finest vessels thus exhibit the same relations as the larger partitions and vessels ; while the small nests of parenchyma-cells answer to the large homogeneous masses of red pulp which are visible to the naked eye. There are nowhere any special coats which include these cells, but the)'\u2019 may be seen everywhere placed immediately on the sheaths of the vessels, the partitions, and the membranes of the Malpighian corpuscles. In the above delineation of the parenchyma-cells, those of man and of the higher mammalia have especially served as the model: but in general a complete similarity obtains in other animals ; and it is only here and there that any specialities show themselves. In many animals \u2014 thus, for instance, in amphibia \u2014 the spleen has often, though not always, very beautiful parenchyma-cells with large nuclei : in birds, and in the scaly Reptilia, granulated and somewhat dark cells are for the most part more frequent. In the hedgehog, rabbit, and guinea-pig, some cells, which are altogether peculiar, occur in company with the ordinary ones. In both the former of these I saw, here and there, large round cells from 10 to 16-1000ths of a line, with three, four, to ten or more nuclei, which often lay so closely together in the middle of the cell that they appeared to make up a mulberry-like mass, like certain large cells which one finds in the marrow of young bones. These cells were by no means uncommon, but gradually diminished in'size towards that of the parenchyma-cells. In the guinea-pig occur round cells, in large quantity, of 48 to 60-10000ths of a line, which contain one or seldom two round granules of a dark contour ; and their nucleus, not always very distinctly visible, is very plainly seen on the application of acetic acid; while, at the same time, the dark granules often disappear.\nThe blood effused in the spleen-pidp, as well as the metamorphoses of the blood globules in the same, demand the greatest consideration both in respect of anatomy and physiology. I believe myself to have been the first who* directed attention to this circumstance, and cor-\n* Loc. cit.","page":781},{"file":"p0782.txt","language":"en","ocr_en":"782\nSPLEEN.\nrectly recognised it ; although Oesterlen, Re-mak,and Handheld Jones had already detected isolated facts having a reference to it. Oesterlen * was the first who found in the spleen of frogs and toads, and with less distinctness in that of the mammalia, yellow, rose-red, and black minute corpuscles, but he was not in a condition to explain them. Remak followed next without greater success ; he found in the spleen-pulp of the calf delicate transparent vesicles, with 1 to 3 round, reddish-yellow homogeneous bodies, the colour of which approximated to that of the blood corpuscles, but which were not so easily swollen out by water. Finally, Handfield Jones j- discovered peculiar yellow corpuscles in the spleen of different vertebrata.\nAll these facts are placed in their true light by my discovery that blood corpuscles are almost constantly undergoing dissolution in the spleen and disappearing. This will be shown as follows : \u2014\nThe red pulp of the spleen in man and animals exhibits at different times a different\nFig. 531.\nCells containing blood corpuscles from the spleen of the Rabbit, magnified 350 diameters.\n1, cells with one, three, four, and seven unchanged blood corpuscles; 2, cells with blood corpuscles undergoing dissolution, and coloured in different shades of brown or yellow (coloured granule cells) ; 3, cells with destroyed and decolorized blood, globules, larger or smaller, and with or without granules ; 4, blood globules altered in colour, diminished or destroyed, either single or aggregated, in small clumps.\nIn 1, 2 and 3 the following letters signify alike : \u2014 a, more or less unchanged blood globules; c, colored granules begun by a diminution or destruction and alteration of colour in blood corpuscles ; d, colourless granules produced by the discoloration of c ; e, nuclei of the cells containing blood corpuscles and their metamorphoses ; f, nucleoli of these nuclei.\ncolouring, or rather a different condition of the blood corpuscles contained in it, and\n* Loc. cit. p. 52.\nf London Medical Gazette, Jan. 1847, pp. 140-142.\nthese, without any participation of the other elements, affect its colour by the different nature of their appearances. Thus, in a particular animal or in the human subject, this substance sometimes possesses a paler or more greyish red, sometimes a brown, or even black-red colour : in the latter case a quantity of altered blood globules are present, the appearances of which will hereafter be described ; while in the former case, it may easily be proved by the microscope that the red colour depends on unaltered blood globules, which are easily separated from the pulp by pressure, and on the application of water give off all their colour in a short space of time. In other animals, the spleen has always about the dark colour mentioned : nevertheless, even in these cases, sometimes only unchanged blood globules are seen ; sometimes many of these are undergoing the most manifold changes.\nNow these changes (figs. 531,532.) are very extraordinary and peculiar, and in all animals depend essentially upon these facts. The blood globules first become at once smaller and darker, while the elliptical corpuscles of the lower vertebrata also become rounder : then, in connection with some blood plasma, they become aggregated into small round heaps ; which heaps, by the appearance of an interior nucleus and of an outer membrane, experience a transition into spherical cells containing blood corpuscles. These are from 5 to 15-1000ths of a line in size, and contain from 1 to 20 blood corpuscles {figs. 531. 1. 532. 1.) During this time the blood corpuscles are continually diminishing in size, and, assuming a golden yellow, brownish-red, or dark colour, they undergo, either immediately or after a previous dissolution, a complete transition into pigment granules. So that these cells themselves are changed into pigmentary granule-cells ; and, finally, by a gradual loss of colour of their granules, they form themselves into completely colourless cells (figs. 531. 3. 532. 4.).\nIn respect of the more special circumstances of this process, it is first necessary to consider the commencement of the cells described, and their changes, somewhat more in detail. As regards the first of these, it is certain that the cells containing the blood corpuscles do not commence directly around a nucleus, but by the circumposition of a membrane around a heap of coagulated blood : in the same way, to wit, that the so-called inflammatory globules of Gluge in certain cases change themselves to cells ; or that by which the smaller globules of fission of the yolk form themselves into vesicles. On the other hand, it remains doubtful whether the nuclei which are seen in these cells are there before the formation of the membrane, or whether they only begin as supplementary to it. If the former be the case, one might add that, in the extravasated or clotted blood of the spleen, nuclei arise in consequence of the commencing organization, each of which then, like the nuclei in the fission of the yolk,","page":782},{"file":"p0783.txt","language":"en","ocr_en":"surrounds itself with a part of the blood (plasma and globules), and, finally, con-\nFig. 532.\nCells containing blood corpuscles, from the spleen of the Frog (Rana temporaria and esculent a), magnified 350 diameters.\n1, cells with one or more blood globules of an intense yellow colour, diminished in size, yet mostly not yet destroyed ; 2, cells with blood globules coloured brown, orange, or black, still more diminished and dissolved (coloured granule cells) ; 3, cells with blood globules much diminished or quite dissolved, and undergoing discolorization (pale-coloured granule-cells) ; 4, cells with completely dissolved and discolorized blood globules (colourless granule-cells) ; 5, coloured granule-cells (like those in 3) in different stages of their transition into black pigment-cells.\nIn 1\u20145 the letters import, as in fig. 351. b, the nuclei of the blood globules.\nditionates the development of a membrane on the surface of the sphere thus commenced. Or one might regard the formation of spheres consisting of some blood plasma and blood globules as the primary phenomenon ; and that then a nucleus begins in each sphere; and that, finally, a membrane is thrown around these. In corroboration of this opinion, Hasse and myself* have observed in the pigeon the occurrence of inflammatory globules, which are without nuclei or membranes, but contain blood globules ; and to this may be added, that in the splenic extravasations blood corpuscles are often grouped together in heaps without being contained in cells. Be this as it may, in any case thus much is certain, that as soon as the cells with their included blood globules are visible, the nuclei are never absent ; and this fact, taken in conjunction with what is already known of the import of nuclei in the process of cell development, speaks strongly for their formation preceding that of the membrane of the said cells.\nThese cells containing blood corpuscles\n* Zeitschrift f\u00fcr Ration. Medicin, Band. iv. S. 1.\n;EN.\t783\nbehave themselves so far alike in all creatures, that their blood corpuscles by degrees disappear and fall to the ground ; and, ultimately, they all seem to be converted into colourless cells, although the methods by which this change occurs are different in different animals ; whence it will be well to go through them one by one.\na. In mammals the cells with unchanged blood corpuscles are not very easily seen, on account of the small size of the latter, and the facility with which they lose their colour ; yet one can easily get a sight of them, provided the examination be made at the right time, and the application of water forborne.\n1 have seen them plainly in man, the rabbit (fig. 531. 1.), guinea-pig, sheep, calf, and dog ; and have found that in these creatures the number of the included blood globules is from 1 to 12, on an average from 2 to 6, and the size of the cells from 5 to 16-1000ths of a line; while their vesicular nuclei have a length of 36-10000ths, and a breadth of 28-10000ths of a line. By the shrinking up and falling to pieces of the blood globules, which immediately renders them darker in colour, coloured granule-cells begin from these cells. They are of a golden yellow, or rusty or brownish yellow, or even blackish colour (fig. 5 31.2.), and gradually experience a transition into cells, with slightly coloured, more numerous, and smaller granules ; and, finally, they take the form of altogether colourless cells, part of which are even poor in granules (fig. 531. 3.). In man, the rabbit, and the guinea-pig were found, besides the cells just described, free granules and heaps of granules, of a golden yellow, brown, or blackish colour; together with altered blood globules, concerning which it seemed to me very probable that they were originally free, and were never included in cells. In other vertebrata, as in the hedge-hog, the cat, and the bat (Vespertilio viyotis and pipistrel/us), the cells with the unchanged blood globules were not observed, although all other stages, from the golden yellow to the altogether colourless granule-cells, were seen. Finally, in others, as in the horse and ass, were seen uncommonly numerous, diminished, and highly coloured blood-globules, both isolated and aggregated ; and the metamorphoses of these into golden, brown, and blackish-yellow heaps of granules, although no definite indication of cell structure could be detected around these heaps.\nb.\tAmongst birds, I have found the round cells in Falco albicillus, Cuculus canorus, Turdus varius, Perdix saxatilis, and Sylvia hortensis. They were in larger or smaller quantity, from 4 to 10-1000ths of a line in size, with dark golden yellow granules which were evidently nothing but metamorphosed blood globules. This was very distinctly shown in Turdus musica, since here the cells occurred with unchanged blood globules. Everywhere these cells experienced a transition, partly into brown and black granule-cells, partly into colorless granulated cells.\nc.\tAmongst the Reptilia. In the scaly","page":783},{"file":"p0784.txt","language":"en","ocr_en":"784\nSPLEEN.\nReptilia, amongst which I have only examined Anguis fragilis and Coluber austriacus, I have seen no cells with unchanged blood globules ; but in the Anguis I found pale yellow, brown, and black granule-cells, which were, as in birds, of from 6 to 10-]000ths of a line in diameter. Transitions of these into faintly yellowish and colourless granule-cells were also present in considerable number, being almost as frequent as the ordinary parenchyma cells in the spleen-pulp. The Coluber austriacus certainly exhibited an effusion of blood in the parenchyma of the spleen, but no changes of the blood corpuscles. The naked amphibia offered a striking contrast. Amongst them I examined Rana temporaria and esculenta, Bornbinator igneus, Hyla arbores, Bufo cinereus, Alytes obstetricans, Salamandra maculata and atra, Triton igneus, t\u00e6niatus, and cristatus. The cells with blood globules were better seen in these than in any other animals. This was especially the case in Triton, Bornbinator, and Rana, in which 5, 10, 20, and more blood globules, with distinct nuclei, were frequently seen occupying a plainly nucleated cell of 6 to 12-1000ths of a line in diameter. The size of the blood globules in these cases allowed their metamorphoses to be followed through all stages, as is represented in fig. 532. At first they were round, of an intense yellow, and less easily altered by water ; then they contracted themselves yet more together, assumed a golden yellow or brown yellow colour, and were no longer assailed by water ; finally, they became colourless, or experienced a transition into black granules, while they generally also fell asunder into smaller granules. In this manner golden and brownish yellow granule-cells (fig. 532. 1.) arise from the cells with unchanged blood globules (fig. 532. 2, 3, 5.), and finally they experience a transition into colourless granule-cells (fig. 532. 4.), or exist for a longer time as black pigment cells.\nd. In fishes I have recognised the same conditions as in the naked amphibia, only they were not so brilliant. The cells with blood globules were very distinctly seen in Salmo fario, Cyprinus carpio and brama, Tinea chry-sitis, Esox lucius, Perea fluviatilis, Coregonus mur\u00e6na, and Gadus lota. In Anguilla fluviatilis, Aspius alburnus, Chondrostoma nasus, leucocephalus, &c., they were less plainly seen; nevertheless, cells with shrunken blood corpuscles, or aggregates of such, occurred also in these. In all fishes these structures become converted partly into colourless granule-cells, partly into black pigment-cells and pigment masses, which finally often lose their colour.\nThe place where the changes of the blood corpuscles above mentioned occur can be demonstrated in some amphibia to be the bloodvessels. Thus, in Triton igneus, the spleen is at its margins tolerably transparent, and here one frequently comes upon the cells which contain blood corpuscles, occupying the capillaries in a row one after another ; and here we are also able to drive them into\nthe larger venous channels by pressure, so that one of these is often filled by a considerable streak, consisting entirely of these altogether characteristic elements. Whether this occurrence is a rule in the Triton, and whether it obtains in other amphibia, I am unable to certify. Yet I may communicate that, in the Triton, frog, toad, and Salamandra atra, I have found these cells containing blood corpuscles even in the trunks of the splenic vein and vena port\u00e6 ; while in Bufo cinereus, Triton igneus, and Salamandra, I have found them in the hepatic branches of the vena portae, even to its capillaries ; and in the latter animal, even in the inferior cava and the heart. In any case, these facts may be considered as conclusive of the not unfrequent occurrence and formation of the cells in question within the bloodvessels of the spleen ; although it can scarcely be added that they are not probably also formed in the extra-vasated blood. In certain genera of fishes, as in Tinea, Esox, Perea, the cells which contain blood corpuscles, and their metamorphoses, are seen included in round delicate-walled vesicles of from l-40th to l-16th of a line in diameter (fig. 533.), which for the most part\nFig. 533.\nFrom the spleen of the Tinea chrysitis.\nsit on the ramifications of the splenic arteries, either laterally on the vessels, or on the points where they divide ; and which are connected with the sheath or exterior membrane of the same ; or, in other words, are nothing else than pouchings of the same. How these vesicles are developed I have not determined, yet I can scarcely doubt that they have the import of false aneurisms, and owe their origin to a tearing of the inner and middle tunics, and to a protrusion of the tunica adventitia, together with the sheath of the vessels (if the latter texture can be supposed to exist here). The similarity of these vesicies with the Malpighian corpuscles of the mammals seems to be especially worthy of mention. After the description already given of the relation of the Malpighian corpuscles to the arteries, it is unnecessary to explain in detail, that the correspondence of both in respect of their site is very great. But, in respect of their contents a similar resemblance is sometimes exhibited, when, as in the cysts of fishes, the cells with blood corpuscles","page":784},{"file":"p0785.txt","language":"en","ocr_en":"SPLEEN.\nhave all undergone a transition into colourless cells, or the Malpighian corpuscles contain effused blood. By pondering upon these circumstances, one might almost come to the idea of regarding the cysts of fishes as Malpighian corpuscles, or the Malpighian corpuscles of mammals as false aneurisms of the splenic arteries ; but in my opinion either of these views would be altogether erroneous. For although blood is often present in the Malpighian corpuscles, yet this appearance is much too seldom to allow of our explaining their contents as arising out of altered blood. And as regards the cysts of fishes, they are altogether absent from many fishes, and, where they are present, often undergo a cretifica-tion, or are changed into concretions ; while they occur in other organs, as for instance in the kidneys : facts which have little conformity with the constant occurrence of the Malpighian corpuscles. In others of the fishes previously mentioned, no vesicles can be recognised in the spleen ; on the contrary, in many genera, the blood corpuscles obtained in different conditions of their metamorphosis are seated together in roundish heaps of a more or less definite outline, and of a size which equals that of the vesicles : these are evidently nothing else than extravasations of blood. The numerous circumscribed red or brown points which occur in the spleen pulp of all fishes, are nothing but the self-decomposing blood globules ; and they are, as above mentioned, either free or arranged in masses which are included in vesicles. In the scaly reptilia, birds, and mammals, it is very difficult to state with certainty in what part of the spleen the formation of the cells which contain the blood corpuscles and their metamorphosis occurs. At first I thought of the hollow interspaces with which the vein of the spleen begins ; only these spaces, as will be shown hereafter, do not in the least obtain in the human subject in the form which has been hitherto attributed to them. Or the branches of the veins, which are always large, might easily be regarded as the locality, provided that the occurrences above mentioned be not regarded as extravasations. With regard to this question direct observation teaches us as follows. In the capillaries and arteries of the spleen in mammalia no changes of the blood corpuscles exist ; so that the only question is, whether the blood corpuscles, which constantly occur in the spleen-pulp, and here undergo their metamorphoses, are situated in the commencements of the veins ; or whether they occupy spaces newly formed by the extrusion of the blood. Much may be adduced in support of the first of these views. Thus, it is scarcely possible to suppose that extravasations of blood in such extraordinary quantity constantly occur in the spleen ; then it may also be mentioned that pigmentary granule-cells, such as are developed in the spleen from the blood, may also be found in bloodvessels exterior to the spleen, which seems to speak for their being situated within the vessels in the case of the spleen itself. I have\nVOL. IV.\n785\nmyself formerly found scattered pigment-cells in human blood * which I can now only regard as granule-cells from the spleen. Ecker has also seen f in the splenic veins of the calf, cells containing blood corpuscles like those in the spleen. And, lastly, Meckel J has also found black pigment-cells in the blood of a woman whose spleen abounded in them. Finallj7, we may recollect, that in the amphibia the cells in question are certainly situated in the vessels. But, on the other side, it must not be forgotten that in the spleen of fishes metamorphoses of the extravasated blood take place, and that also portions of the extravasations enter the vessels, and that it is possible the pigment-cells in the blood may thus originate ; finally, that the masses of blood in the spleen-pulp are scarcely defined with the sharpness which they would possess even in veins with very delicate coats. In this state of things it is much better to abstain from giving a definite decision ; or if one be absolutely required, to attribute the metamorphoses of the blood in the spleen of mammals to both the localities mentioned.\nThe changes of the blood globules in the spleen are not exactly similar in all circumstances, either as regards the quantity of the cells thus changed, or the degree of metamorphosis which they undergo. In fishes, all the blood globules, without exception, may be recognised as decomposing ; yet the quantity of these varies, i. e. the number and size of the vesicles and masses previously described varies in a considerable degree in different individuals and species, although no very definite laws have as yet been found out. Reptilia exhibited the following peculiarity. In newly-caught individuals, the cells containing blood corpuscles were very numerous and distinct ; but in those which had fasted one, two, or three days, they occurred in exceedingly small quantity ; while, finally, by a longer duration of the fasting (a week or more), they exhibited themselves in very great number, and of extraordinary distinctness ; while at the same time the spleen became large, dark red, and very rich in the normal blood corpuscles. When newts which had fasted a week were fed, the cells previously existing, and the unchanged blood corpuscles, vanished, since they were changed into colored granule-cells, and only on the sixth day after the feeding did such cells reappear ; but in three days afterwards almost all of these had again experienced a metamorphosis into granule-cells. In mammalia I have, in a series of cases, seen the decompositions of the blood corpuscles in as little as five, six, and more hours after eating, while immediately after the reception of food, or after a day\u2019s fasting, I have failed to observe it. At my advice, Landis \u00a7 instituted experi-\n* See also Fahrner, De Globulorum Sanguinis origine : Turici, 1845, p. 26. fig. 143.\nf Zeitschrift f\u00fcr Rationelle Medicin, Band vi. S. 264.\nJ Zeitschrift f\u00fcr Psychiatrie, 1847, S. 22.\n\u00a7 Beitr\u00e4ge zur Lehre \u00fcber die Verrichtungen der Milz : Zurich, 1847.\n3 E","page":785},{"file":"p0786.txt","language":"en","ocr_en":"786\nSPLEEN.\nments concerning this on thirty rabbits, and obtained the following results. Of fifteen animals which were examined, two, five, and eight hours after eating, cells with unchanged blood globules were found in eleven ; in five they were in masses ; in six separate ; in four cases they did not occur at all. Fifteen other animals, which were killed twelve, twenty-four, and forty-eight hours after eating, showed in eleven cases no trace of the cells mentioned ; in two cases many were present, in two cases a few only. And, vice vers\u00e2, golden yellow granule-cells (metamorphoses of the cells with unchanged blood globules) occurred fourteen times in the latter animals ; ten times in great quantity, once in considerable numbers, and three limes very sparingly, while in one instance only were they altogether wanting. In the fifteen animals first mentioned these were twice absent, five times sparingly present, twice in considerable numbers, and six times in large quantity. The conclusion to be deduced from these facts is, that cells with unchanged blood globules only show themselves a short time after eating, and that the granule-cells which proceed from these are almost always present, although in greater number in animals which have fasted a considerable time. If any animal were examined at the proper time, one would be astonished at the uncommon quantity of decomposing blood globules; for in such a case the whole red part of the pulp consists (so to speak) of nothing but golden yellow or blackish corpuscles, which are the different metamorphoses of blood corpuscles already mentioned.\nOf the ultimate destiny of the blood corpuscles so metamorphosed, thus much is certain,\u2014that they are decomposed and dissolved ; but, on the other hand, it is difficult to make out what is the destiny of the cells which usually enclose them We have already seen above that these cells occur in the splenic vein, the vena port\u00e6, and the inferior cava, and it is thence questionable whether all these cells may not possibly pass into the blood. It is difficult to give an answer to this. Thus much I consider to be made out ;\n\u25a0\u2014that cells with unchanged blood globules, and yellow, brown, or blackish-yellow granule-cells, only exceptionally and seldom pass into the blood of the splenic vein, or beyond ; since, in the first place, these cells are, upon the whole, rarely found in the blood ; while, secondly, their occurrence in the spleen is demonstrably very frequent. -On the other hand, as to the colourless granule-cells which finally arise from the cells containing blood corpuscles, it is not made out whether they remain in the spleen or enter the blood. Supposing the first of these to be the case, they may either abide a considerable time in the pulp, and then in a certain manner serve as parench}ina-cells, with which they have a great similarity, or they may experience a dissolution, and altogether disappear. In the second case, one may imagine that they are converted into lymph corpuscles, with which\nthey have, to some extent, a great similarity\u00bb or that they undergo a solution in the blood of the portal vein and the rest of the circulation. I own that I cannot hazard a decision. It is certain that colourless granule-cells occur in the blood as well as in the spleen ; but it is also certain that they are much more frequent in the spleen, and that, as regards the blood of extravasation which undergoes metamorphosis, it may be definitely stated, that its products for the most part remain in the same place.\nSo much for my experience of the decomposition of blood corpuscles in the spleen. Simultaneously with myself, Professor Ecker, of Basle, made similar observations, which likewise referred to a destruction of blood corpuscles, and which, soon after, lent an additional light to mine.* In contradiction to this, however, Gerlach has lately uttered the opinion that my observations allude to the formation of colored corpuscles within colorless ones; so that he explains the forms of cells which are found in the spleen in precisely the reverse way, and supposes that the cells with golden yellow granules are the younger, and those with unchanged blood corpuscles the elder ; that is, that they are those in which the blood corpuscles have completely developed themselves, and from which they are ready to be expelled or set free. So that if Gerlach be correct, the relation of the blood corpuscles to the spleen is precisely the reverse of that which I have stated, and they begin there in great quantities ; and it thus becomes important to inquire whose opinion is the correct one. But if my experiments upon the behaviour of the blood corpuscles in the spleen have no other consideration. this merit, at least, remains to them, that they accurately set forth the anatomical facts, and in this manner have already sufficed to refute such false theories as that of Gerlach. In point of fact, Gerlach is altogether wrong when he supposes that the golden yellow granules are changed into blood globules ; for this can in no way be proved, but very easily the contrary. He is equally in error in adducing, as a ground for this view, that blood corpuscles begin as cells in the embryonal liver,\u2014a statement which is altogether incorrect. And when he finally adduces that since, according to Harless f, the blood corpuscles are destroyed bv the alternating influence of nitrogen and carbonic acid, a second kind of solution of these in the spleen cannot be conceived ; it need only be remarked that this theory of Harless\u2019s is not in the least proved as regards the living organism. So, also, Virchow J has expressed himself as partially against mine and Ecker\u2019s account ; since, though he does not at all doubt the dissolution of blood corpuscles, yet he altogether denies the origin of cells around\n* Loc. cit.\nt lieber den Einfluss der Gase auf die Form der Blutkugelchen : Erlangen, 1846.\n+ Archiv f\u00fcr pathologische Anatomie und klinische Medicin, Band i. SS. 452. 483. ^","page":786},{"file":"p0787.txt","language":"en","ocr_en":"SPLEEN.\nheaps of blood corpuscles. This statement is only explicable by supposing that the Mammalia and Reptilia, in whom this phenomenon can be seen as plainly as could be wished, were not examined by Virchow. Besides, I do not maintain that the effused blood always forms cells containing blood corpuscles ; only I hold it as a fact established beyond all doubt, that this very frequently happens in the spleen as well as in extravasations in the lungs, lymphatic glands, brain, and thyroid body ; and while 1 believe that the formation of cells around these several effusions is not an equivalent fact, yet it is altogether certain that blood globules enclosed in cells undergo a more speedy dissolution than if they remain free.\nIn conclusion, one.. word concerning the import of the changes of the blood corpuscles in the spleen. It may be asked, whether they constitute a normal and physiological, or a pathological appearance ? On the one side, very weighty grounds may be alleged for the normal character, especially their (so to speak) constant occurrence and innumerable quantity in such a number of animals living in their natural condition, as the amphibia and fishes were. Furthermore, the apparently complete health which existed in spite of the vast quantity of dissolving blood globules. Thirdly, in Reptilia, the cells containing blood corpuscles may b\u00eb seen in bloodvessels which are in no way isolated from the general circulation. Fourthly, similar and constant changes of the blood repeated at short intervals are absent from other organs of birds, mammals, and reptiles ; and many other arguments might be adduced. But, in contrast to these facts, many others appear on a more careful contemplation, which may almost lead to the opinion that all the changes of the blood globules in the spleen are possibly only pathological appearances. In fishes, dissolutions of the blood corpuscles occur not only in the spleen, but in an exactly similar way in other organs, namely in the kidneys, the liver, and the peritoneum. In the first of these organs their presence is constant; at least, in the examination of many examples of eel, pike, Coregonus mur\u00e6na and mur\u00e6nula, Salmo fario, Barbus fluviatilis, Cyprinus brama and carpio, and Tinea chrysitis, not only were they always present, but almost always as numerous as they were observed to be in the spleen. In the peritoneum and the liver they were sometimes scarce, sometimes frequent, but only in the carp and Tinea chrysitis were they constant ; in other fishes they were either altogether absent, or only occurred here and there, as in the trout. If to these facts be appended that in certain animals, \u2014 to wit, in cats, sheep, and others, \u2014 the changes of the blood corpuscles in the spleen are very seldom observed, one can scarcely resist the notion that the appearance is abnormal ; and this is much more the case when one considers that similar appearances which are known not to be physiological, constitute almost constant occurrences, and are asso-\n787\nciated with exactly parallel changes of blood globules. Of this, the small effusions of blood in the lungs, bronchial glands, and thyroid bodies of men, and those of the lymphatic glands and mesentery of pigs and rabbits, are instances. But this latter view is insusceptible of full explanation ; for although pathological effusions and metamorphoses of blood often constitute almost a constant occurence, yet, first, the quantity of blood globules which undergo dissolution in such effusions is in no comparison at all with that of the millions which are destroyed in the spleen ; and, secondly, it has yet to be shown that effusions of blood may not occur as a physiological phenomenon, as happens in the bursting of a Graafian follicle in the ovary, in menstruation, and in the separation of the placenta. And although all animals do not show in the spleen such a solution of the blood corpuscles as can be verified by the microscope, yet it is by no means proved therewith, that where tiffs takes place it depends on a pathological condition ; indeed, the blood corpuscles of different animals may undergo dissolution in different ways. At least thus much is certain, that in all animals, without exception, stagnations of blood occur in the spleen ; and I might add, almost of a certainty, in mammals, extravasations also. In these stagnations, the blood globules may dissolve themselves in the one case rapidly, in the other case slowly, and thus, according to the outer phenomenon, a difference will be produced. Such an occurrence may be physiological, since it is, at least in many animals, visibly constant and very extensive ; and it may have the greatest signification to the life of the organism. Therefore, so long as the pathological character of the phenomenon; s not proved of a certainty, I am disposed to hold fast by its physiological nature, and to consider the dissolution of the blood corpuscles in the spleen as a normal fact.\n6. Bloodvessels of the spleen. \u2014 The splenic artery (arteria lienalis) springs from the c\u00e6liac axis, and courses with many windings between the layers of the gastro-colic ligament until it reaches the fundus of the stomach, where it enters the gastro-splenic ligament, after giving off some small twigs to the pancreas and the stomach. Arriving in the neighbourhood of the hilus lienalis, it divides into a superior and an inferior branch. The upper of the two, passing somewhat upwards, and giving backwards from two to six short arteries (vasa brema) to the large extremity or pouch of the stomach, divides into from three to six branches, which, lying in a line one over another, extend to the hilus, into which they enter. The inferior branch is somewhat larger than the others ; it passes to the inferior and anterior part of the spleen, supplying it with three to six branches, which enter the hilus in the same manner as the others, and it ends finally as the gastro-epiploica sinistra. Thus, all the six to twelve branches which enter the spleenjie tolerably 3 E 2","page":787},{"file":"p0788.txt","language":"en","ocr_en":"788\nSPLEEN.\nin one line upon each other in the gastro-splenic omentum, and they are also connected to each other by fat and areolar tissue. The size of the splenic arteries is very considerable in proportion to that of the organ, and so also the thickness of their coats is worthy of notice. In the first of these respects, it is possible that only the thyroid gland exceeds the spleen ; the liver, which is so much larger than this organ, being supplied by an artery of scarcely larger size than the splenic, although we must not overlook the fact, that beside this the liver receives very much additional blood through the vena port\u00e6. In the mammalia generally, the splenic artery is proportionally smaller than in men ; this possibly depends only upon the more considerable contraction of the vessel at their death. Wintringham finds that the thickness of the arterial coats is greater than that of the aorta above the giving off of the renal arteries, to which it bears the ratio of 1 to 0'762 ; he also states that they will sustain a pressure of 41 lbs.\nThe serous covering of the spleen receives some unnamed small arteries : thus a twig is given to it from the left inferior phrenic artery, which courses in the phrenico-lienal ligament ; and, besides this, it receives branches from the first lumbar, from the left spermatic, and from the splenic itself. Additionally to these, in some of the vertebrata, to wit in the calf, small twigs in great number leave the substance of the spleen, and after perforating the fibrous coat of the organ spread themselves out upon its surface.\nThe splenic vein altogether corresponds in distribution to the splenic artery. Sc many primary arterial branches enter the hilus of the spleen, and just as many veins come out of it. These six to twelve veins unite into two branches, and receiving, the upper the venae breves from the stomach, and the lower the vena gastro-epiploica sinistra, they constitute the trunk of the vein. In the spleen, and at their emergence from it, the veins lie anterior to the arteries, but then they place themselves posteriorly to them ; and it is behind the arteries that they unite to form the common trunk. This trunk receives a twig from the pancreas, from the lymphatics of the spleen, from the stomach, and, further, the vena coro-naria ventriculi ; it then passes away over the aorta to the under surface of the liver ; and, finally, with the vena mesenterica superior it c\u00f6nstitutes the trunk of the vena portae.\nThe splenic vein, like all the branches of the vena portae, has no valves, and is the largest branch which assists to form that trunk. Its width is very considerable: according to E.Home* and Giesker, the proportion to that of the arteries is as \u00f4 to I ; and according to earlier authorities it is yet more. The proportionate size of the branches is still larger ; and, according to C. A. Schmidt, their ratio in the spleen itself to that of the arteries\n* On the Structure and Uses of the Spleen, Phil. Trans, for 1808.\nwhich run with them is as 20 to 1. In contrast to this, the thickness of their coats is very inconsiderable, and, according to Wintringham, is to that of the arteries as 1 to 4'8 or 4*3, to that of the iliac vein as 1 to 3*5.\nOn their entry into the spleen, both arterial and venous branches receive as a covering a process ofthat \u201ctunica propria\u201d of the spleen which forms the vagin\u0153 vasorum, previously described.\nThese are not alike in all animals : thus, for instance, they differ in man from those exhibited by the higher brute mammalia \u2014 a fact which explains the various descriptions given by different authors. In man, the sheaths of the vessels form complete coats around them. A section made in the centre of the hilus, and continued through the spleen, exhibits them very distinctly as projections or processes of the tunica propria, and also allows their further circumstances to be seen. It is thus shown that arteries, veins, and nerves are thickly enclosed in these sheaths ; but in such wise that they are easily separated and isolated, especially in old, or macerated, or boiled spleens. The arteries and nerves allow of this more easily than the veins, which latter have a closer connection to these sheaths. It is further seen that not only are the trunks of entering and emerging vessels thus covered, but that their finer ramifications receive a similar clothing. The thickness of these sheaths is in the human subject by no means inconsiderable. As Giesker correctly states, they are at first exactly the thickness of the tunica propria, and retain the same thickness for a considerable distance, that is, as long as they clothe the main trunks of the vessels. On the branches which proceed laterally from these trunks, and on their further extent, the sheaths become naturally finer, and gradually increase this fineness as the vessels become more minute, until finally, becoming very delicate, they lose themselves in the pulp of the spleen in the manner previously mentioned. The thickness of a sheath is always less than that of the coat of the artery which it incloses, and greater than that of the vein ; yet this does not hold good of vessels in all parts of their extent, since on the finest branches the sheaths are proportionally somewhat stronger than on the larger ones. As to the relations of the sheaths to the rest of the spleen substance, it must especially be considered that they do not lie free in the parenchyma of the organ, but are connected with the general trabecular network by means of balks which are given off from them: but these balks are not so numerous as different anatomists appear to think ; so that we are scarcely entitled to consider with Giesker, that the whole trabecular network is formed out of this connection.\nIn other Mammalia, as in the horse, ass, ox, pig, sheep, &c., the course of these sheaths differs in some respects from that seen in man. In the three latter animals, which in this respect are best known to me, no","page":788},{"file":"p0789.txt","language":"en","ocr_en":"SPLEEN.\t789\nsheaths at all are found on the smaller veins, and on the larger they are chiefly found on that side on which the arteries and nerves which accompany them lie. Only the two primary trunks of the veins which proceed from the spleen have for a very short distance a complete sheath, while all the arteries, even the finest, possess one ; a condition of which more will be said hereafter.\nThe minute structure of the sheaths of the vessels in man altogether correspond with that of the partitions ; and this holds good of animals generally. But I have not been able to detect unstriped muscular fibre in the sheaths in all those cases in which I have found it in the trabeculae. In oxen this is especially the case ; while, on the contrary, in pigs, &c., they are very plainly present.\nGreat difficulties oppose the inquiry concerning the distribution of the vessels in the spleen itself : since, lstly, injection or inflation of the vessels gives little result on account of the delicacy of the organ ; and, 2dly, great difficulties are connected with the microscopic examination of the organ. What will be now adduced concerning it is especially the result of the latter method of inquiry, which, combined with fine preparations by the knife, has seemed to me to be the most fertile in results.\nWhen the main branches of the splenic artery have entered into the spleen they lie in their sheaths, each in company with a vein, to which they are posterior and inferior : they are in tolerably loose connection with the sheath, and not unfrequently they take a serpentine course. In their further distribution they do not behave as arteries generally do, which continually give off smaller branches, but they divide immediately into a quantity of different large and long branches in the manner of a shrub ; of these the larger branches go to the anterior, the smaller to the posterior, margin of the organ. Beside this, it is especially to be remarked of the arteries of the spleen, that their different branches form no anastomoses. Assolant tied a branch of the splenic artery in a living dog, and then allowed the spleen to return into the cavity of the belly. The dog died thirty hours after : much inflammation and exsudation of a bloody serous fluid was found in the belly, and the spleen was quite healthy ; only the part cut off from the circulation of the blood was gangrenous, and, as it were, separated from the sound part by a line of demarcation. In contrast to this, Heusinger tied all the branches of the splenic artery, one only excepted ; upon dissection, the whole spleen was found to be mortified, excepting the part in which the artery not deligated ramified. Also injections in an artery always return solely by the corresponding branch of vein ; and they only fill that region of the spleen in which the branch ramifies, never passing over into any other. I am unable from my own experience to pass any judgment upon these data, and will therefore not\nimpugn them ; but I may be allowed to doubt whether the capillaries of the pulp are completely separated from each other, and am more inclined to believe that, in consequence of the anatomical circumstances of the pulp, such a separation must be considered as impossible ; since in the spleen we have before us, not a gland with special lobes separated from each other, but a parenchyma everywhere united. The above results of deligation and injection by no means necessarily imply an isolated course of the capillaries, and are fully explained by the supposition that the arteries possess no anastomoses.\nWhen the arteries have divided into small vessels of 1 to 2-100ths of a line, they come into contact with the Malpighian corpuscles in the mode already described ; while they are also connected to these by their sheaths. According to Giesker, their final terminations are coronal or pencil-shaped, radiating so as to surround the Malpighian corpuscles, and altogether enclose them ; then arriving at the highest point of the vesicle, they return upon themselves in the shape of a loop, course back again as veins, and there meet together, beneath the point whence the artery radiated, to form a vein, which enters the same sheath from which the artery emerged. At this point the sheath divides into three to four fibrous threads, which pass over on the spleen corpuscles to the threads arising nearest to them, and unite with these. If we compare with this description of the minute anatomy of the spleen that which is considered most admissible by J. M\u00fcller, the next author after Giesker, we shall find very considerable contradictions. J. M\u00fcller finds that the smallest branches of arteries partly continue on the side of the corpuscles without giving off branches to them, partly perforate either a portion or the whole of the corpuscle, without in any instance leaving any branches of the artery in its interior; that these fine arterial branches pass through the middle of the corpuscles, then continue on their coats, and then quit them altogether ; and that if an artery in the corpuscle divides into many branches\u2014which never happens on the surface, but always in the thickness of its coats \u2014 these branches leave it again, in order to ramify minutely in the surrounding red pulpy substance of the spleen, into which part especially all the fine pencil-shaped ramifications of the arteries pass. The commencements of the veins spring from these branches ; they are tolerably large, anastomose frequently with each other, and scarcely have a special coat as yet. If a little piece of the pulp of the spleen be carefully examined, it will be seen that it is as if cribriform, and constitutes as it were a network of red partitions, the diameters of which are larger than the interspaces and canals existing between them. It is these venous canals which give the cellular appearance seen in inflation of the veins of the pulp, and which, injected, form structures resembling the corpora cavernosa of the","page":789},{"file":"p0790.txt","language":"en","ocr_en":"790\nSPLEEN.\npenis. Special cells or cavities do not exist.\nSo far J. Miiller. If we now ask ourselves the reason of these important differences between these two authors cited, one of whom affirms the continuation of the tufts in the pulp, and a connection of Malpighian corpuscles with arteries and venous interstices only ; while the other denies all this, we shall find it not very difficult to give an answer. Giesker, in his description, limited himself to the appearances met with in the human subject, while J. Miiller made the pig and the ox the basis of his delineation. This circumstance will at least partially explain the want of correspondence in the two descriptions ; for 1 find that between the spleen of man and that of the animals mentioned considerable differences exist.\nIn man, at least generally, the arteries together with the veins pass deeply into the substance of the spleen, lying in the same sheath with them, and exactly following their course. According to Giesker, the two classes of vessels accompany each other even to their final ramifications ; but this is not correct. In every spleen instances occur, which are easily seen, where small veins and arteries lie very close to each other ; and Giesker has evidently allowed himself to regard these particular instances as the rule, and has extended it as a description to the smallest branches of vessels. But if an arterial and venous primary branch be successively followed to their minutest ramifications, it will be seen that, sooner or later, every artery and vein, without exception, separate from each other, and follow their special path. It is not at all unusual to find this even with arteries from I to 1 line in diameter, but it is always the case with those of from 1 -10th of a line. In such an instance the artery, setting out alone, does not perforate the sheath in which it hitherto lay, but takes with it a distinct yet often inseparable covering of the same ; so that from this point forwards a special and separate venous and arterial sheath exist. And in man the Malpighian corpuscles lie only on these isolated arteries ; a state which Malpighi and Miiller had already described in Mammalia.\nAs regards the other circumstances of the arteries, I have found them exactly as Miiller describes them in the lower animals. After the smaller branches of the arteries are connected with the Malpighian corpuscles, they enter into the red spleen substance, and immediately upon this each small trunk spreads out in the shape of a tuft into a large number of yet finer arteries (Jig. 526, d.) ; and these tufts or pencils of arteries, lying in great numbers close to each other, give to the terminations of the arterial trunks a very beautiful appearance, which may be best compared to the broad crown of a (pollard) tree. These separate tufts, dividing and diminishing in size yet more, terminate by an immediate transition into the true capillaries ; which, in a more and most minute form of 3 to 5-1000ths\nof a line, constitute a close and beautiful network in the separate portions of the pulp, and in those parts of it which surround the Malpighian corpuscles ; although they do not form a special vascular covering for the same. Many authors seem to deny the existence of capillaries in the spleen : thus Engel * has lately altogether denied them; but this is quite erroneous. They may easily be seen in the pulp of the human spleen, by the aid of the microscope, both empty and filled with blood, and exhibit themselves as in no way different from the capillaries of other organs ; and the finest of them have a diameter of only 3-1000ths of a line. J. Miiller is also in error when he describes the arteries as coursing through the coats of the Malpighian corpuscle, since they always pass on its exterior. Finally, Giesker is wrong in describing the arterial pencils as spreading themselves out on the Malpighian corpuscle, and here becoming continuous with the veins ; even in man it is not difficult to discover that the pencils only begin beyond the corpuscles, that they lie in the pulp, and that it is here they first break up into capillaries.\nGiesker at least partially agrees with this statement when he says f that the pulp consists of nothing but the minutest arteries and veins united by fibrous tissue. The sheaths of the vessels above described are just as much more delicate as are the vessels themselves, and they are finally lost as distinct coats on the capillaries ; here they form delicate fibrous membranes which connect the capillaries together, and under this form they pass through the whole of the pulp.\nAs to the veins, I must first, with Giesker, express myself in the most decided manner against all the more ancient and modern anatomists who suppose and describe venous spaces (sinus venosi) in the human spleen. I have bestowed the greatest attention to the dilated commencements of the veins in ques-tion, and it was only my own researches that led me to renounce the opinion that these dilatations really exist ; indeed I have never been able to discover anything special or extraordinary about these veins. Firstly, as to the larger veins, which are as yet accompanied by the arteries, there is nothing very remarkable about them, with the exception of their considerable size, which has been already mentioned. They all have a membrane which is continuous with that of the smaller veins, and is least separable on that side with which the artery is in contact ; this membrane is only distinguishable from the sheath of the vessels by its greater delicacy, and in company with this sheath it gradually diminishes its thickness. Orifices of the smaller veins, constituting the so-called stigmata Malpighi, are present in very small numbers in the larger veins ; while, on the other hand, they are somewhat more frequent in the smaller of the vessels in question. When the veins\n* Zeitschrift der Gesellschaft der Aerzte in Wien, 1847.\nf Loc. cit. S. 166.","page":790},{"file":"p0791.txt","language":"en","ocr_en":"SPLEEN.\t791\nleave the arteries and pursue their way alone, they vary in some respects from this description, although not so considerably as might be imagined from the delineations which have been given of them. In the first place, the character of the branchings is peculiar, since from hence onwards, and so much the more frequently the smaller the veins become, branches are given oft\u2019 from the veins on all sides at very nearly right angles, and the open mouths of these ramifications are seen from within as numerous round or oval orifices lying very closely to each other. In the second place, the membranes of these veins gradually become thinner and thinner, and at the same time are blended with the similarly attenuated sheaths, so that both constitute only one delicate membrane, which is nevertheless everywhere demonstrable even in the smallest vessels which can be isolated, and which everywhere exhibits itself without any interruption as a perfectly continuous membrane. Dilatations or pouchings can nowhere be seen, either in the course of the isolated veins or in their smallest branches ; only it must be added, that the narrowing of their calibre occurs much more slowly than in the arteries. As to the beginnings of the veins, and their connection with the capillaries, I have not been able to detect anything more than what one sees elsewhere ; namely, that by a constant simplification and attenuation of their structure, the veins finally pass into capillaries. Here also no traces of dilatations are visible, of whatever kind these dilatations might be imagined to be ; and there is just as little appearance of any other peculiarity.\nAs regards the brute mammalia, many of them certainly correspond in a very considerable degree with man, in respect of the condition of these vessels ; but my researches do not extend sufficiently to enable me to express myself decisively on this point. While, on the other hand, some, as the horse, ass, ox, pig, and sheep, exhibit essential differences. In the latter animal, which I have examined the most carefully, the following deviations are present. The arteries differ little from those of man, only they separate earlier from the veins to pursue their isolated course. In most other respects they behave precisely as J. Muller has described them, and as I have also spoken of them in man ; only I cannot corroborate the statement of M\u00fcller, that the sheaths of the smaller arteries are equal in strength to those of the greater. The ramifications which reach the Malpighian corpuscles measure from lto 1 i-100ths ofaline in diameter; they then course in the pulp, form very beautiful tufts, and finally capillaries, of which the smallest measure from 3 to 4-lOOOths of a line. But in contrast to this, the veins exhibit very essential differences. In the first place, a special membrane and sheath are only found in the largest venous trunks, and even here they only extend a short distance around the circumference of the vessel ; while more deeply in the spleen thejr only' lie\nupon the side where the artery and nerve are attached to the vein. In all the smaller veins which are no longer accompanied by arteries, there is no trace of these two membranes to be seen ; and not only is this the case, but the mode in which the precise limit of the venous canal is indicated is also very extraordinary. The vein appears to be formed in the first instance by the strong anastomosing trabeculae, and soon afterwards it seems composed simply of delicate fibres and red substance deposited between them, a structure which continues even into the large venous trunks. They thus distinguish themselves at the first glance as excavations in the parenchyma of the spleen, which are devoid of walls. Nevertheless, by a more careful examination of the red limits of these veins, one may verify their smooth and shining appearances, a circumstance which is significant of the existence of a delicate membranous covering ; and, in point of fact, microscopic investigation proves the existence of an epithe-\nF,g. 534.\nEpithelial cells from the Splenic vein of Man and other Mammalia. Magnified 350 diameters.\nHum, which every where clothes this surface, and consists of fusiform or more spherical cells, of-J to l-100th ofaline in diameter, with roundish or elongated nuclei of 3 to 5-lOOOths of a line in size (fig. 534.). This epithelium altogether corresponds with that which covers the part of the veins possessing a visible membrane ; but in the vessels of which I am speaking, it is placed in part immediately on the \"trabeculae, in part upon a delicate fibrous membrane limiting that part of the pulp which bounds the veins. In consequence of what has been said, the greater number of the splenic veins of the ox must be likened in respect of their structure to the spaces in the corpora cavernosa penis, and to the sinuses of the dura mater; since, instead of the venous membranes elsewhere present, they possess only the \u201c tunica intima \u201d in the shape of a delicate epithelium. So that one may speak of them as \u201c venous sinuses,\u201d and the more correctly, if it be considered that these veins, almost devoid of walls, possess a colossal width, and are everywhere rendered quite cribriform by larger and smaller veins opening into their interior ; which smaller veins may themselves be traced by their great width for a considerable distance. How these smaller veins are connected with the very distinct capillary net-3 e 4","page":791},{"file":"p0792.txt","language":"en","ocr_en":"792\nSPLEEN.\nwork of the pulp, I have not been able to find out ; and I do not believe that either injection or inflation of the vein, or a microscopic examination, will ever give any definite conclusion hereto. For these vessels, often possessing but a few little trabeculae for their coats, are of such a delicate texture, that they tear by the slightest mechanical force, while by the microscope they cannot be distinguished from the surrounding constituents of the pulp. Yet thus much one may see, that the veins gradually become very small,\u2014so small, that it is quite impossible to talk of their commencing as dilated spaces. For my own part, I am convinced that a similar communication obtains between the veins and capillaries of oxen as of men ; and that the only possible difference is, that the veins here possess only an epithelium, and must therefore be connected with the capillaries in a somewhat different way. I will yet further add, that in microscopic examination of the pulp of animals, skeins of epithelium are not unfre-quently found, consisting of roundish cells, as it were, fused together : these can only come from the small venous trunks.\nThe following may be noticed concerning the microscropic structure of the splenic vessels : \u2014The arteries everywhere possess their three usual coats. The inner consists, first, of an\nFig. 535.\nEpithelial cells from the human Splenic artery, a, shorter cells ; b, somewhat longer cells.\nepithelium of spindle-shaped cells, which easily come off in skeins or separately (fig. 535, a, b) ; and, secondly, of an elastic membrane of homogeneous composition, wrinkled in the longitudinal direction (fig. 528, <?.), and with or without openings : which openings although very small, are visible even in the arteries of the tufts. The middle tunic is very thick, and gives rise to the considerable thickness \u00f4f the wall of the vessel ; it contains very little else but unstriped muscular fibres. In the larger and largest arteries, nets of elastic fibre and elastic membrane (gefenslirle memhranen of Henle) are also present, while they exist without exception on the vessels which pass to the Malpighian corpuscles, and on those which form the pencils or tufts. The adventitious for cellular) coat is altogether absent from the smaller vessels in the interior of the spleen, and is here represented by the sheath ; but it exists in the larger vessels, and presents white fibrous tissue and meshes of elastic fibres.\nThe capillaries (fig. 536.) have\u2019a simple, structureless membrane, with nuclei lying on its\nFig. 536.\nCapillary from the Spleen of the Pig. Magnified 350 diameters.\ninner surface. The veins have been already described as they exist in brute mammalia : in man they possess\u2014 1. An epithelium as above described ; 2. A membrane of elastic longitudinal fibres ; 3. Transverse unstriped muscular fibres, in a single or double layer, which are present in the trunk of the splenic vein and all its primary branches in the interior of the spleen, but are absent from the smaller and smallest veins ; 4. White fibrous tissue, with elastic fibres which take a longitudinal direction. The smallest veins possess only white fibrous tissue with elastic fibres, and an epithelium.\nSo much has been already said above concerning the blood of the splenic vessels and of the spleen, that I will here only append some special observations made upon animals. In a dog whose spleen abounded in the dissolving blood globules, the blood of the splenic vein distinguished itself by a very great quantity of colourless blood corpuscles, almost all of which contained numerous nuclei, and often had a deceptive resemblance to pus globules. In the blood of the liver were found a great number of altogether different blood Fig. 537.\nBlood corpuscles from the liver and Splenic vein of a Dog, with yellow crystals of a substance resembling H\u00e6matine.\nglobules'f/g. 537.). These were swollen out and almost colorless, but contained from 1 to 5 thinner or thicker small rods of a dark yellow colour ; part of these possessed the same length as the blood globules, part were shorter. These small rods were unchanged in water, but in acetic acid they seemed to disappear. In a second dog I found the same cells with small yellow rods in the blood of the splenic vein, while they could not be detected in any other part of the body. With them I found at the same time numerous colourless blood globules with manifold nuclei. In the fresh-water perch, the blood","page":792},{"file":"p0793.txt","language":"en","ocr_en":"SPLEEN.\n793\nof the splenic vein of many individuals contained numerous golden yellow cells with diminished blood globules. In the same blood, and in the splenic pulp, there also occurred, either sparingly or in uncommon quantity, rod-shaped crystalline corpuscles, of a yellow colour, and a length of 4 to 6-1000ths of a line : at the first glance they seemed to be lying altogether free, and they were dissolved by potash {fig. 538, b). On the application of water a membrane was upraised from these\nFig. 538.\nSimilar blood corpuscles from the Spleen and Splenic vein of the fresh-water Perch, a, crystals and nuclei seen on treating colourless nucleated blood corpuscles with water ; b, crystals apparently free.\nsmall rods, and near them a nucleus came into view {fig. 538, a). On more accurate inquiry, it plainly appeared that these small rods lie in decolorized blood globules, and in unchanged blood globules the gradual formation of one, or even two, of these may be followed. In Barbus fiuviatilis, the spleen pulp contains an enormous quantity of really free crystals ; these are of a violet and reddish colour, and of a nail or spindle-shaped form ; and on the application of acetic acid, they are completely dissolved, leaving some colour behind. Crystals such as these also occurred sparingly in the kidneys, the liver, and the blood of the heart. In this animal, as well as in Cyprinus brama, the blood contained yellow granule-cells, like those which occur in the spleen and kidneys. All the rod-shaped yellow corpuscles just named (of which the first, indeed, are nothing but crystals) must in any case consist of a substance allied to the h\u00e6matin of the blood ; and possibly they consist of the substance which Virchow has lately named h\u00e6matoidin, with which they correspond in some respects. Their occurrence in the spleen is physiologically interesting, and so also is their formation within the blood corpuscles, while at the same time it affords a very plain indication of the relation of h\u00e6matin to them.\n7. Lymphatics. \u2014 The views of authors concerning the lymphatics of the spleen are very contradictory, since one class have the precedent of Haller for altogether denying their existence in the human spleen, while others have stated their existence in abundance, and have constituted the spleen, in a certain measure, a large lymphatic ganglion. This difference mainly depends hereon,\u2014that the one class have specially examined the human spleen, while others have chiefly drawn their conclusions from that of the lower animals, considerable differences in respect of these vessels existing in different creatures. In man, the lymphatics\nof the spleen are, at any rate, in utterly in\" considerable quantit}', being rather less nu\" merous than in other glandular organs, as the liver and kidneys, and not at all so numerous as in the lymphatic glands. They are divisible into superficial and deep. The former course, in sparing numbers, between the two coats of the spleen, and form in this situation delicate trunks, which anastomose with each other ; but, excepting in perfectly healthy spleens, and in the neighbourhood of the hilus, they can scarcely be recognised. The latter lie in sparing numbers in the hilus, and in the sheaths of the vessels, where they accompany the arteries, although they cannot be traced so far as there. Both sets of these vessels pass to the gastro-splenic omentum, to enter the small lymphatic glands placed there ; and finally they collect to a trunk which opens into the thoracic duct, at about the eleventh or twelfth dorsal vertebra. All these lymphatic vessels can only be thus seen in the quite fresh and undeteriorated spleens of executed criminals or subjects killed by accidents, although they may often be recognised in particular parts of the healthy spleen after natural death, especially if the vessels be tied and the spleen soaked in water. But, on the other hand, in diseased spleens it is very rare to see even a trace of them, unless a preparation be made of a small gland in the gastro-splenic ligament, in which case small entering and emerging trunks may be recognised.\nIn the lower animals, or at least in many of them, the lymphatics seem to be more numerous. Moreschi distended the lymphatics of the spleen in fishes (in whom they possess no valves) from the trunk, and he says that the injected spleen appeared to consist almost solely of a network of absorbents. But in another place he freely states that the spleen consists, so to speak, of nothing but vessels. In a Testudo mydas, Tiedemann and Gmelin saw all the absorbents of the small intestine going to the spleen, in which, by interlacing with arteries and veins, they formed a network. From this network large branches, like the emergent vessels of the lymphatic glands, took their course towards the thoracic duct. Almost all the older writers recognised the richness of the spleen in lymphatics, which later examiners have but confirmed. But it will be well to set forth one fact which, in my opinion, is not sufficiently estimated, namely that even here absorbents are only sparingly present in the interior of the spleen ; at least I have found this to be the case in the pig, ox, sheep, &c. Here the superficial lymphatics are, as is well known, very numerous, and this fact seems to me to correspond with the circumstance that in these animals the serous and fibrous coats are only loosely connected to each other, and contain many vessels in the loose areolar tissue between them. But, on the other hand, if the vessels in the hilus be examined, only a few scattered trunks can be seen, a condition which stands in extraordinary contrast with the very numerous lymphatics of the coats. Thus, for","page":793},{"file":"p0794.txt","language":"en","ocr_en":"794?\nSPLEEN.\ninstance, in the hilus of a large calf I found only four trunks of lymphatics, which together possessed a diameter of only 176-1000ths of a line; while the interior of the spleen is also poor in lymphatics, for, so far as I have seen, the numerous plexuses of lymphatic trunks in the coats of the spleen have no relation with the interior of the organ, but at least the greater number of them belong solely to the subserous areolar tissue.\nAs to the distribution of the lymphatics in the spleen, it may easily be seen, by observations on oxen, that they only follow the course of the arteries, lying with these inside the sheaths; while the veins, which take a solitary course, and (as was before mentioned) possess no sheath, are also devoid of these companions. I have not seen the commencement of the lymphatics, yet I can state for a certainty, that they have nothing to do with the Malpighian corpuscles, since these corpuscles are completely closed, as was before mentioned. And, I will add, in support of this my view, that the small arteries which pass to the Malpighian corpuscles are no longer accompanied by lymphatic vessels ; at least microscopic examination detects no trace of such vessels within their sheaths. Just as little does the pulp possess any lymphatics ; for if these, like the nerves (see below), pass from the sheaths of the arteries into the pulp, they would in such a case be visible. And from what has been said, I conclude that the lymphatic vessels of the interior of the spleen belong wholly and solely to the sheaths of the arteries, and not in the least to the pulp or the Malpighian corpuscles : and thus that here they play precisely the same rather subordinate part which they do in the liver, where they pertain to the capsule of Glisson, and not to the glandular substance ; or as in the kidneys, in the interior of which they only accompany the bloodvessels. Concerning the structure of the lymphatic vessels, I can only state thus much ; that in the calf they possess, at least in their main trunks, three membranes : \u2014 1. An epithelium similar to that of the arteries ; 2. A circular fibrous membrane, composed of two or three layers of very distinct unstriped muscular fibres ; 3. An outer membrane of white fibrous tissue. Valves occur in the deep as well as in the superficial lymphatics.\n8. Nerves. \u2014 The nerves of the spleen arise from the splenic plexus, and accompany the splenic artery as two or three interlacing trunks, and divide in such wise at the giving oft'of its branches, that each artery receives one, or very frequently two nerves, which accompany it, and here and there anastomose with each other. The thickness of the primary nervous trunks varies very much in different creatures. Thus in the sheep, and especially in the ox, they are of really a colossal size, and taken all together, their diameter equals that of the empty and contracted splenic arteries ; while in man and the pig they are no way remarkable in size, and are many times smaller\nthan the arteries. These differences, which led the earlier authors to speak of the splenic nerves in similarly different expressions, were at first altogether inexplicable to me, since I could not understand why the spleen of one animal should possess so much larger nerves than another. On a more careful examination, the microscope gave a very simple and unforeseen explanation. The uncommon size of the splenic nerves of Ruminantia depends solely on this, \u2014 that the white fibrous tissue of these nerves is disproportionally developed in the shape of the so-called \u201c fibres of Remak,\u201d while it is much less prominent in the same nerves of other animals. A comparison of the splenic nerves of the pig and calf has taught me that if we limit our inquiry to the number of primitive nerve fibres, scarce any difference exists between the two sets of nerves. But, on the other hand, the primitive nerve fibres of the pig lie very closely together, so that they cannot be numbered without considerable trouble ; while as an example of their condition in the calf, I will adduce the following: \u2014 The trunks of the nerves entering the hilus were seven in number, with a diameter of *57, % *04.8, -6, \u201848, -48, \u20226 (line) ; and they contained respectively only 28, 7, 6,9, 13, 9, 22 primitive nerve fibres. In the lower animals, the nerves may be followed with the knife for a considerable distance into the spleen, much further than in man ; and with the help of the microscope, I have very frequently followed them even on the arteries which go to the Malpighian corpuscles. I have been just as little able as Remak to find any ganglia on the arteries in the interior of the spleen. Concerning their mode of termination, I am only able to say thus much ; that the nerves also pass into the pulp, and may even be easily seen on the pencils of arteries, and finally that they disappear as very small branches of not greater size than the smallest capillaries ; but I am unable to decide whether they terminate by means of\nNig. 539.\nA very small nerve from the Spleen of the Calf, without any visible primitive nerve fibres, and apparently consisting only of neurilemma (or fibres of Remak). Magnified 350 diameters.","page":794},{"file":"p0795.txt","language":"en","ocr_en":"SPLEEN.\n795\nloops or with free extremities. In the calf, the thickness of these smallest nerves on arteries of a line in diameter (where it is not uncommon to find two such trunks) is 24 to 28-1000ths of a line ; on the pencils of arteries 48 to 56-10,OOOths ; on the smallest arteries and capillaries 3 to 4-1 OOOths. Their structure was so far peculiar, that in the calf the finest nerves (fig. 539.) exhibited no trace of nerve fibres, even when treated with soda and acetic acid, but they seemed to consist wholly and solely of the fibres of Remak. Nevertheless, in branches of 12 to 28-1000ths of aline, I have often very plainly seen a single\nFig. 540.\nA somewhat larger nerve, in which may he seen a single dark nerve fibre : also from the Calf. Magnified 350 diameters.\nnerve tubule of 20 to 28-10,OOOths of a line (fig. 540.), with dark margins, in the midst of the fibres of Remak. From these facts it may be concluded that the finest nerve tubes in the spleen of the calf are devoid of the dark borders, just as they are in the organ of smell according to Todd and Bowman ; or as in the Pacinian corpuscles, the cornea, &c. ; but we are scarcely able to conclude therefrom that they possess the same constitution in the adult animal. I will here permit myself to\nFig. 541.\nTwo primitive nerve fibres given off from the trunk of the splenic nerve of the Calf, about an inch before its entry into the Spleen. Magnified 350 diameters.\nadd an interesting microscopic observation concerning the splenic nerves of the calf. A division of the primitive nerve fibres takes place in them (fig. 541.), similar to that which Henle and myself found in the Pacinian corpuscles, Miiller, Br\u00fccke, and R. Wagner in the muscles, and Savi and R. Wagner in the electrical organ of the torpedo. But what is altogether neiv in the minute anatomy of nerve is, that these divisions do not take place at the terminations of the primitive nerve fibres, but in their trunks. I detected them in the large trunks which accompany the splenic artery previously to its entering the hilus ; and, indeed, in considerable numbers, so that I often counted three or four such divisions in one preparation. They always took place by the division of a primitive nerve fibre at an acute angle into two parts, and never gave rise to more fibres. These divisions often repeated themselves on the same fibre, so that in one instance three, and in another case even four, fibres were given off by the successive divisions of a single primitive fibre : this happened in the smaller branches in the interior ; but, so far as I could remark, it did not occur in the smallest branches of nerves, although, from the difficulty of examining the finer nerves, I cannot say that such divisions were absolutely wanting here. The signification of these facts seems to be very important, both in an anatomical and physiological point of view, but this is not the place to give a more detailed statement. But thus much will I remark : that by means of such a distribution of the nerves, a small nerve may be rendered subservient to a larger organ ; and, in addition, an harmonious activity of the whole organ may be facilitated ; while, finally, in respect to sensation, it may possibly explain the want of an exact local sensibility.\nIn concluding this treatise on the anatomy of the spleen, I will allow myself briefly to propound somewhat concerning the physiological and pathological properties of the organ.\nThe spleen is developed at the end of the second or the beginning of the third month, in the f\u0153tal mesogastrium at the fundus of the stomach. It originates from a blastema which is developed independently in this situation, and neither proceeds from the intestine, like that of the liver, nor from the pancreas, as Arnold has maintained ; since, although in the ruminants it is placed on this gland, yet in the dog, according to Bischoff, it is not. It is at first a small, white, often slightly tabulated corpuscle, which gradually reddens, and soon becomes as rich in vessels and blood as it is in the adult. The elements of the f\u0153tal spleen are originally quite uniform cells ; at a later period part of these are transformed into fibres and vessels, while part become persistent as the parenchyma-cells. It is only subsequently that the Malpighian corpuscles are developed, yet I have found them, without exception, both in man and animals, at the end of the f\u0153tal life. According to Heusinger, the proportion of the","page":795},{"file":"p0796.txt","language":"en","ocr_en":"796\nSPLEEN.\nspleen to the whole body is, in an embryo of ten weeks old, as 1 to 3000 ; in the eighth month it is, according to Huschke, as 1 to 720 ; while at birth, he states it to be as 1 to 357 ; in the adult as 1 to 235 to 400 ; and in old age as 1 to 600 to 800. From these data it will be seen, that the proportionate weight of the spleen to that of the whole body increases very rapidly in the embryo, and is almost as great at the period of birth as in the adult ; from which it sufficiently follows, that the spleen is an organ, the activity of which extends from the end of the foetal period through the whole life, and reaches its highest point in middle age.\nAs regards the function of the spleen, of the innumerable theories and hypotheses respecting it, only a very few deserve a nearer consideration ; namely, only those which place the spleen in intimate relation ivith the life of the blood. In point of fact, almost all the facts which with greater or less certainty we know concerning the spleen, and, above all, the anatomical ones, point to such a relation. Hew-son had already stated, that when an organ receives more blood than it requires for its own nutrition, we may conclude therefrom that that blood undergoes a change in it, or a secretory process takes place ; and this expression will not apply to any organ in the body better than to the spleen, which must be considered as relatively better supplied with blood than any other organ. Therefore since all pathological, anatomical, and physiological facts prove a relation of the spleen to the blood, we may securely assume, that a change of the blood takes place in the spleen. The only difficulty is to know what change. Firstly, the blood may either suffer a change in its transition from the arteries to the veins ; or, secondly, the separation of a particular lymph from the blood may take place in this organ. It is well known that the latter view was first maintained by Hewson *, who at the same time announced that the lymph generated in the spleen serves to form blood corpuscles ; and since then, Tiedemann and Gmelin have specially supported the same view. But the grounds adduced for this theory seem to me to be insufficient. At one time, the great quantity of lymphatics in the spleen was brought to prove that a special lymph was developed here. But that part of the spleen on which special stress is laid, namely, the interior or parenchyma, is quite poor in lymphatic vessels ; and its surface, even in the lower animals, scarce contains more of such vessels than other organs ; to wit, the peritoneum covering the liver, the pleura covering the lungs, &c. Therefore the formation of a special lymph by the spleen can as little be assumed as in the case of the lungs and liver. Secondly, the red colour of the spleen-lymph, and its greater coagulability, have been adduced as proofs of a peculiarity, and of a blood-forming import. But it may be demanded, are these properties constant, and on\n* Opus posthumum, sive rubrarum sanguinis par-ticularum thyrni et lienis descriptio, 178G.\nwhat do they depend ? As to the first question, it is* certain that a red colour of the spleen-lymph is, on the whole an exception, as Seiler and Ficinus * formerly stated. In rabbits, cats, or dogs, I have never found such a colour, and have also always found the chyle of the thoracic duct of only different shades of white. But I will not deny that in calves and sheep a reddish spleen-lymph is often found, and I will add that this is frequently the case in the horse. But this is sometimes the case in other organs, as, for instance, in the liver and in the lacteals, where Tiedemann and Gmelin in some cases also found a reddish and very easily coagulable fluid ; and it is important to observe, that the reddish colour and easy coagulability in these cases depend simply on blood which is mixed with the lymph. Thus, if the reddish spleen-lymph of a calf be examined, a quantity of fully developed blood corpuscles are found in it, which are altogether identical with those in the blood.'j' Now since it cannot be assumed that real coloured blood globules are formed in the lymphatic vessels of the spleen, and since, in point of fact, all trace of such a developement of blood globules is absent, it will only follow from the facts adduced, that in the cases of reddish spleen-lymph a mixture of real blood and lymph has taken place. This mixture may be the result of normal anastomoses between lymph and bloodvessels, or may owe its origin to a rupture of both these vessels. I believe the latter to be the case, and am simply of the opinion that it is not at all to be wondered at. For in Tiedemann\u2019s cases the animals were either killed by a blow on the head, or died during convulsions ; and it is not surprising that during such a death-struggle an organ so richly supplied with blood as the spleen should make an abnormal path for that fluid, or that a similar thing should happen when the vena porta has been tied. It is well enough known, how easily the lymphatics of the spleen are filled by an injection into the bloodvessels. The reddish colour and easy coagulability of the spleen-lymph in particular cases therefore proves nothing at all, except that, on account of its great vascularity, blood is more easily extra-vasated in the spleen than elsewhere, and enters the lymphatic vessels. Thirdly and lastly, Tiedemann and Gmelin adduce the above-mentioned course of the lymphatics in the tortoise as a powerful proof of their view ; but Rudolphi J found exactly the contrary, since in two large sea-tortoises not a single lymphatic of the intestine passed to the spleen, but they all went directly to the thoracic duct.\nIn consequence of what has been said \u2014 which I might also corroborate by many other facts could I go more into detail \u2014 it is impossible to imagine the development of a special lymph in the spleen ; and hence the\n* See Giesker, S. 265.\nf See also Nasse, (Wagner\u2019s Handw\u00f6rterbuch der Physiologie, Band ii. S. 370.)\n\u00ce Physiologic, Band ii. Heft 2. S. 156.","page":796},{"file":"p0797.txt","language":"en","ocr_en":"SPLEEN.\t797\ntheory which ascribes to the spleen a relation to the lymphatic system, and considers it as in a certain manner a large lymphatic gland, is utterly devoid of meaning. In this manner there remains as a last resource the view, that changes occur in the blood itself contained in the spleen. But what is the nature of these changes ? Are blood corpuscles possibly formed in the spleen, as has been already so often supposed ? Certainly not ; for in the most rigorous examination of the blood in the spleen and the larger splenic vessels, just as in the spleen-lymph, no trace whatever of the formation of blood globules can be detected, much less in blood which is exactly reversed, and is exhibiting, as I might say, at every step the plainest and most lively indications of a dissolution and decomposition. Let us recall to mind the details already given of the condition of the blood globules in the spleen. Upon the facts there mentioned, in the year 1847 * I founded the conjecture that the blood corpuscles undergo solution in the spleen, and that their colouring matter is employed m preparing the colouring matter of the bile ; a conjecture which seems to me preferable to all those which have hitherto been offered concerning the function of the spleen. If the fact be made out that new blood globules are continually arising from the cells of the chyle, it is just as certain that the blood globules must also slowly disappear in order to make room for those newly arising. And if it be considered that nobody has yet seen the least trace of a solution of blood globules in any other organ, and that, on the contrary, 1 have found in the spleen a healthy organ, in which, in all four classes of vertebrate animals, blood corpuscles are almost constantly undergoing decomposition, even in uncommon quantities, it will, I think, be conceded to me that I have some grounds for setting forth the hypothesis here given. It is, indeed, as yet not altogether settled whether the changes of the blood seen by me are normal or abnormal ; but, as was previously remarked, so long as their pathological nature is not proved with certainty, I must continue to regard them as physiological and pertaining to healthy life. But this is not saying that they occur in all creatures in the method described above. It is highly possible that blood globules undergo dissolution in the spleen without previously forming the cells containing blood corpuscles : an opinion which is corroborated by the blood globules described above as occurring in the blood of the splenic vein of the dog and fresh-water perch : these contained crystals of h\u00e6matine or some kindred substance, and were evidently near their destruction. Indeed, it is even possible that such a direct mode of dissolution may be the rule in some animals, perhaps even in many. And although I have regarded the spleen as an organ in which the blood corpuscles undergo dissolution, yet I have not maintained therewith\n* Loc. cit. S. 135.\nthat it is in all animals the only organ in which any thing of this kind occurs : it would therefore in no way militate against my theory if it should ever turn out that in the kidneys of fishes, the vessels of which are arranged so peculiarly, a constant and physiological solution of blood globules obtained. The following circumstances also speak for my hypothesis. That in no other way can any reasonable account be given of the changes of the blood in the spleen. Furthermore, that it elucidates the relation of the spleen to the portal system of veins ; since according to it, the dissolved blood corpuscles are subservient to the formation of the bile, the colouring matter of which is so nearly allied to that of the blood. Finally, that, as will be more fully stated below, the pathological facts are proportionally in unison with it.\nOn all these grounds I am therefore inclined to defend the hypothesis first set forth by me of a destruction of the blood globules in the spleen ; and the more so, that J. Bedard has lately maintained, that the blood of the splenic vein is always poorer in blood corpuscles than that of the other veins. He has stated this in a memoir which was laid before the Acad\u00e9mie des Sciences in Paris on the 17th January, 1848, and published in the \u201c Archives g\u00e9n\u00e9rales de M\u00e9dicine\u201d of October to December, 1848. Since J. Bedard\u2019s results are an important support to my hypothesis, I have permitted myself to communicate here the most important of them. B\u00e9-clard has analysed the blood from the lower branch of the splenic vein, and that from the jugular vein, in fourteen dogs and two horses. In most of the instances of the analysis, (1.) the water, (2.) the blood corpuscles and fibrine, and (3.) the albumen and salts, were separated from each other ; and only in the horses were the blood corpuscles and fibrine obtained separately. A deficiency of the blood globules and fibrine was always present in the splenic vein, which diminution out of a 1000 parts of blood, amounted to the following quantities in the sixteen cases.\n16*54\t15*94\t8*51\n37*11\t19*67\t13*06\n19*43\t20*80\t14*91\n12*82\t10*88\t9*40\n13*92\t16*06\t\n13*60\t14*78\t\nOn an average of the sixteen cases, the deficiency amounted to 16*08 parts. As regards the albumen, on the contrary, there was a constant increase of this constituent in all the sixteen cases, in an average of 13*02 parts. Finally, in the two analyses in which the quantity of fibrine was certified, there was the extraordinary increase in its quantity in the blood of the splenic vein of 0*3 and 0*5 parts. B\u00e9clard deduces the same conclusion from these facts w'hich I have drawn from my microscopical examinations ; namely, that the blood corpuscles normally undergo dissolution in the spleen ; and 1 regard this conclusion as neither more nor less correctly deduced than","page":797},{"file":"p0798.txt","language":"en","ocr_en":"798\nSPLEEN.\nmine, for it is clear that the results of his analyses may solely depend upon this fact, that in the animals he examined, the changes which I have verified in the blood globules of the spleen, were going on in an energetic manner. If these visible changes of the blood globules,\n\u2014\twhich certainly occur in a most exquisite manner in the horse and dog,\u2014if they be normal appearances, then is the diminution in the quantity of the blood globules, which Bedard found on analysis, also a normal phenomenon ; but if not, then he only examined a blood partially deprived of its globules by stagnation and effusion. The results of chemical analysis would then only be secure, if it were at the same time shown, that there were no visible changes of the blood globules in the spleens of the animals examined. Until this takes place, Bedard\u2019s conclusion will remain, like mine, hypothetical ; although this is in no way diminishing the merit of his observations, since I hold my own hypothesis as one which I am perfectly justified in propounding in the present state of our knowledge. But even if we suppose that the blood corpuscles are destroyed in the spleen, it is nevertheless a question how this dissolution is super-induced, and at what time it comes to pass. As regards the first of these points, in my writing previously mentioned I expressed the opinion, that the spleen is a contractile organ, and may, by virtue of its contractility, be able to dilate and contract itself,\n\u2014\tto fill itself with blood, and again to expel the blood from it. In the state of filling itself with blood, a stagnation of blood occurs in the smaller vessels, perhaps even an extravasation ; and in this stagnant blood, the blood globules undergo destruction, since they slowly dissolve themselves, either free or inclosed in cells. This view I still regard as correct. For, firstly, it is a matter of fact that the spleen does enlarge and diminish its size, and certainly under vital circumstances which are altogether normal. Very many of the older observers have accepted this fact ; as Lieu-tand, Haller, Stuekeley, Rush, Clarke, Hodgkin, Home, and Dobson. This is shown by an examination of the splenic region in the living human subject (Piorry). So also it is shown by vivisection of animals, in whom I have myself seen (and especially in the dog) a very distict diminution and rounding of its outer surface. Finally, Landis *, by weighing the spleen, has recognised a distinct increase and diminution of weight. He examined at different times thirty rabbits, and finds that the average weight of the organ in five observations was :\n12 hours after eating, 0'768 grammes\n5\n8\n24\n48\n2\n99\n99\n99\n\u2022588\n\u2022548\n\u2022526\n\u2022510\n\u2022444\n99\n99\n99\n99\n99\n\u2022t\nNow although it may be freely conceded that\n* Loc. cit.\nf The \u201c gramme \u201d is 15J grains Troy English. (Transi.)\nan organ like the spleen is subject to so many variations in respect of size as to render thirty observations much too small a number to afford any very definite information concerning its increase or decrease of size, it must, nevertheless, be considered, that Landis has examined the proportion of the spleen to the whole body, and to many other organs, as the stomach, liver, and kidneys, and that from this means he derived a- confirmation of what the estimate of its absolute weight had previously taught ; so that his observations must be regarded as a meritorious contribution to our knowledge respecting the changes of volume which the spleen experiences. We now ask, secondly, how these changes come to pass ? B\u00e9clard states that the spleen enlarges and becomes filled with blood in consequence of the splenic vein being compressed by a muscular force ; but the nature of this he has not stated, nor can I regard his view as correct. I believe myself to have propounded a better theory when I stated, that the spleen becomes turgescent in consequence of the relaxation of the muscular fibres which exist in its balks, coats, and vessel-sheaths ; or in animals from whom these are absent, through a relaxation of the muscular fibres of the vessels themselves. A constriction of the splenic vein cannot be supposed to obtain, since the muscular fibres which it contains are but very little developed, and no other compressing force is present ; while, on the contrary, we know that in all animals the splenic artery is uncommonly muscular, and that the partitions of the spleen themselves contain distinct muscular fibres. It is these muscles and no others which, according to my researches, produce the distension of the spleen ; but not through their contracting together, but by their relaxation, which brings with it a distension of the vessels with blood, and a slower circulation of this fluid. The diminution in the size of the spleen occurs simply through the contraction of the muscular parts just named. Precisely in the same manner the corpora cavernosa of the penis become filled with blood by a relaxation of the muscles situated in their fibrous partitions ; and become poorer in blood, and smaller in size, when the muscles again contract themselves. Of course, both here and in the spleen, the nerves play an important part in the process ; probably in consequence of antagonistic relations between them and other parts of the nervous system, which at present cannot be accurately indicated. Thirdly, and finally, it may be asked, whether the blood corpuscles simply dissolve because the blood of the spleen becomes stagnant at certain times, or whether special influences are necessary to this effect ? \u2014 whether the parenchyma of the spleen or the Malpighian corpuscles may not secrete a juice, a \u201c sulcus lietialis,\u201d of which the earlier authors speak, which exerts a solvent influence on the blood corpuscles ? As a kind of vague answer to this question, I have examined the parenchyma with respect to its","page":798},{"file":"p0799.txt","language":"en","ocr_en":"SPLEEN.\n799\nreaction, and have found that without exception it has an energetic acid reaction.. This appeared to me very extraordinary, and the more so when I thought of the great quantity of blood which the organ contains; and I was already captivated by the conjecture that this acid reaction might be of great importance. But I found that litmus paper was just as much reddened by the liver and kidneys of the calf and rabbit ; and, further, that the muscular substance of the heart and the muscles of the trunk have the same effect. So that this acid reaction appears to be a general phenomenon, which is probably due to the fact, that the acids lately found by Liebig in muscle (lactic and inosic acids\") also occur elsewhere. At any rate since there is as yet no exact chemical analysis of the spleen, I cannot express myself concerning the import of this vigorously acid reaction of its parenchyma ; although it is very conceivable, that the acid reaction does not depend on the same causes in all organs.\nAs regards the time at which the blood globules experience their dissolution in the spleen, nothing definite can at present be said ; but my theory appears at least to presuppose, that this process especially comes to pass some time after the reception of nutriment, since I have found the spleen of the greatest size in animals at about the time of five to twelve hours after eating, the same time at which the visible changes of the blood globules were most marked. The cause of this phenomenon seems to be, that the volume of the blood is increased after each time of taking food, and especially that a great number of new cells enter from the chyle. And if an equal weight is to remain in the organism, then, on the other hand, just as many elements of the blood must be dissolved, as there have new ones entered into it ; and this is exactly what happens in the spleen. Besides, I am not anxious to maintain that the spleen may not become distended, and blood globules undergo dissolution, at other times than those just mentioned ; probably the conditions of the liver have also a great influence upon the events in the spleen, so that in hyper\u00e6mia of the liver, the spleen becomes also distended ; and so likewise the nervous system may be interested therein. B\u00e9clard, who has also found many variations in the blood globules contained in the blood of the splenic vein, is unable to assign any definite cause for these varieties, and only remarks, that in the case of a blood rich in blood globules, the amount of these lost in the spleen was greater than in the opposite case. So that it must be left to the future to bring to light the more special relations of the dissolution of the blood globules in the spleen.\nI have hitherto said nothing concerning the function of the Malpighian corpuscles of the spleen. I do not regard their function as at all a peculiar one, since ( 1.), in many animals, as fishes and naked amphibia, these corpuscles are absent ; 2. their constituents exactly correspond with those of the parenchyma of the spleen.\nI believe that the parenchyma-cells and the cells of the Malpighian corpuscles play exactly the same part, although I am just as little able as my predecessors to say with certainty what this is. If they are not subservient to the formation of a special fluid which takes a part in the solution of the blood corpuscles, I should be almost inclined to ascribe to the parenchyma-cells the mechanical use of forming in the first place a soft parenchyma in which the minute vessels can extend at their pleasure ; and nextly, that they, as well as the elements of the Malpighian corpuscles, are simply expressions of the fact, that the spleen, as a highly vascular organ, is everywhere permeated by a fluid which is very rich in plastic matters. At the same time, it may be imagined that all these cells elaborate the fluid in which they are soaked, and after a certain kind of assimilation, again part with it, and through the blood and lymph vessels transmit it to the general circulation. The swelling up of the Malpighian corpuscles after the use of food is quite consonant with this notion. But whether this fluid is of a peculiar nature, and of different properties from that of other organs, we can only know from future chemical researches ; and then only can it be determined, whether or no we are to ascribe to it a special signification.\nIf the spleen be the only or even the chief organ in which blood globules undergo their dissolution, in either case the part which they enact in the organism is by no means the subordinate one which many have hitherto considered it ; but one which is very full of import. And the results afforded by vivisections and by pathology are by no means so contradictory to this expression as they are generally maintained to be. It is true that the spleen of animals may be excised without causing their death, a fact which I have myself repeatedly witnessed ; it is also certain, that men can live without spleens, or with spleens completely atrophied, or rendered functionally useless by degeneration ; nay, in many cases, may live without any disturbance at all,\u2014a circumstance which is also true of animals. But what does this prove ? Nothing at all ; for if the spleen fails, then indeed other organs undertake its functions, and discharge them vicariously for it. Probably in these cases the blood globules undergo dissolution in the general mass of the blood, or possibly in the liver. But if this be so, the spleen is surely not therefore devoid of import or function. With equal correctness might we say, that one kidney is superfluous, because in certain cases an hypertrophied kidney enacts the part of both ; or might regard kidneys generally as devoid of import, because certain rare instances of misdevelope-ment are narrated, in which the skin or the thoracic glands have undertaken the excretion of the urinary constituents. If the spleen is not the only organ in which blood corpuscles undergo dissolution, it is possible that these are destroyed in some small quantity in the capillaries of ail the organs of the body,","page":799},{"file":"p0800.txt","language":"en","ocr_en":"800\nSPLEEN.\nMany observers, as Leeanu and Letellier, and more recently J. B\u00e9clard, have found a diminution in the quantity of blood corpuscles in the venous blood generally, although others have denied this. If this he the case, it confirms such a supposition, and would effectually explain the results of extirpation. In any case thus much is certain, that they afford no grounds for regarding the spleen as devoid of signification. Finally, we may remark in addition, that not unfrequently extirpations of the spleen give rise to considerable disturbances, and especially of the biliary secretion ; a fact which very well corresponds with my supposition that the colouring matter of the bile arises from the h\u00e6matin set free in the spleen.\nIf this theory of the function of the spleen which I have set forth, which Ecker has adopted, and which J. B\u00e9clard has now confirmed, be correct, it will be able to explain the diseased conditions of the spleen and their operation on the organism. But this is at present impossible, since these conditions are much too little known to allow us to say anything even approximatively correct and secure concerning their origin and import. Therefore, instead of entering upon a discursive detail of possibilities resting upon an altogether hypothetical basis, it seems to me much more suitable, simply to indicate the points to which future observers might properly direct their special attention. It is known that the enlargements of the spleen, which constitute the most serious diseases of the organ, have a special coincidence with complaints in which either a dissolution, or some other abnormal condition of the blood is present. This is the case in typhus, typhoid cholera, pyaemia, putrid exanthemata (erysipelas, scarlatina, measles), dyscrasia of drunkards, ague, scurvy, purpura, chlorosis, acute rheumatism, acute tuberculosis, &c. May not the enlargement of the spleen possibly have a share in the production of these diseases, without being so entirely secondary as most pathologists have hitherto assumed ? Is it not conceivable, that in a spleen which is enlarged and distended with blood, a destruction and dissolution of the blood globules is going on on too large a scale, so that the normal composition of the blood becomes seriously prejudiced thereby ? In such a case the blood would be poorer in blood globules, but its plasma would be rich in colouring matter, and possibly at first in fibrine, as J. B\u00e9clard found it to be in his analysis. May not chlorosis or scurvy, in which a considerable diminution of the blood corpuscles has been shown to exist, possibly depend in part on the disproportionate activity of an enlarged spleen ? In consequence of such a too considerable destruction of blood globules in other cases, further changes of the blood may be induced, which may then end as an overcharging of the fluid with colouring matter ; to wit, with the colouring matter of the bile ; or as a pyaemia or the so-called white blood. On the other\nhand, is it not possible, that in cases of the temporary diminution, or inflammation, or degeneration, or atrophy of the spleen, other organs may undertake its functions ?\u2014as, for instance, the liver, which, indeed, is usually hypertrophied in such cases ; or the general mass of blood, a state which must again give rise to peculiar phenomena ? Thus, in respect of its pathology there is much which might yet be observed, if I did not consider it more suitable to conclude with the remark, that in order to the building of a larger superstructure upon the anatomical and physiological basis here given, and in aiming at anything respecting the pathology of the organ, a deliberate, careful inquiry is above all things necessary, an inquiry in which chemical analysis, microscopical research, experiment, and pathological experience, will have to go hand in hand. For if I have perhaps been able to elucidate the spleen in many respects more correctly than my predecessors, yet this account is very far from a final termination of our knowledge, and must be regarded as nothing more than a foundation-stone for an altogether new superstructure.\nMorbid Anatomy. \u2014 Variations in number and form have already been alluded to. The absence of the organ is usually or always accompanied by that of other and neighbouring viscera.\nOn account of the obscurity which has hitherto attached to the anatomy of the organ, its diseased conditions are little understood ; and it is obvious, that until morbid conditions of the spleen are examined and classified with reference to the appearances of their several anatomical constituents, thei\u2019e will be little to be said under the head of morbid anatomy, besides enumerating the most prominent deviations of its bulk, colour, and consistence.\nEnlargement of the spleen is, perhaps, the most common of all the outward deviations. We have already seen that, within certain and very wide limits, the size of the spleen may vary, and that these wide variations are of constant occurrence even in the healthy subject, being intimately associated with its function and that of the organ. It is, therefore, only when such enlargement becomes excessive, or is associated with an alteration of texture, or occurs in the course of some of those diseases which it is known usually to accompany, that we are justified in regarding it as essentially morbid.\nThe enlargement of the organ, to all outward appearance, depends mainly on the increased mass of the contained blood, and is hence sometimes called hyper\u00e6mia ; and the most obvious distinction of this enlargement is into two kinds :\u2014one in which the congestion is produced mechanically ; the other, in which the determination of blood to the organ can only be accounted for on the supposition of non-mechanical causes. The former of the two classes would include the swollen spleens which occur in obstructions of the portal vein, or of the vena cava, as happens in some diseases of the liver and heart respectively.","page":800},{"file":"p0801.txt","language":"en","ocr_en":"STATISTICS.\n801\nIn such instances, there is little appearance of any thing morbid beyond the increase of size. The contained blood is usually very dark, and the spleen shares the deepening of colour. By long duration, the capsule of the organ and the fibrous tissues generally, become somewhat thickened, but in other respects the texture is little altered. In the second class, in which the swelling is probably produced by a peculiar state of the blood (dysci'asia), and is certainly associated with a class of blood diseases, the texture of the organ is usually much altered. The size of the spleen is often astonishingly increased, so that it possesses a volume of from 100 to 300 cubic inches, and a weight of 10-20 lbs. The increase includes, besides blood, a considerable quantity of a fibrinous material, the nature of which, and its relations to the healthy organ, are at present little known. The colour and consistence are of every possible gradation ; from greyish to deep brownish red, or from a soft, friable mass, to a dense, firm, and almost fibrous texture. There is a general relation of these changes to the date and duration of the swelling ; thus in acute or recent cases, the organ is usually soft and of a dark colour, while by long continuance, or in chronic diseases, its consistence is greatly increased, and its colour, as well as that of the contained blood, is much paler or greyer than natural. Atrojphy of the spleen, or slow and permanent diminution of its size, is much more infrequent than the preceding converse condition. It is associated with similar varieties of colour and consistence.\nInflammation of the spleen. \u2014 The peritoneal surface of the organ shares in the diseases of this structure generali)\u2019, and an inflammation of this part of the serous membrane not un-frequently accompanies the enlargements previously mentioned. The exsudation and results are no way peculiar. Concerning inflammation of the parenchyma of the spleen little can at present be said. The large and numerous veins which it contains are liable to inflammation, the secondary being the more frequent form of phlebitis which affects them.\nAs regards other morbid products, organised and unorganised, the spleen offers nothing deserving a special notice.\nBibliography. \u2014 M. Malpighi, De Liene, in Exercitationibus de Yiscerum Structura, Lond. 1669. 12. F. Ruysch, De Glandulis, Fibris, Cellu-lisque Lienalibus, Epist. Anat. Quart. Opera omnia. A. V. Leeuwenhoek, Microscopical Observations on the Structure of the Spleen, Phil. Transact. 1706, p. 2305. T. Douglass, Observations on the Glands in the Human Spleen, Phil. Transact. 1714, p. 499. W. Stuckeley, Of the Spleen, its Description and History, Uses and Diseases, Lond. 1722. B. S. Albinus, De Liene, in Anotat. Academ. lib. vii. cap. 14. p. 84. De Lasbne, Histoire Anatomique de la Rate, M\u00e9moires de l\u2019Academ. de Paris, 1754. T. IAeutaud, Observation sur la Grosseur Naturelle de la Rate, Mem. de l\u2019Acad. de Paris, 1788. W. Hew-son, Experimental Inquiries, Lond. 1776; et Opus Posthumum, Lugd. Bot., 1786. L. et T. P. Asso-lanti, Recherches sur la Rate, Paris, 1801. A. Mores-chi, Del vero e primario Uso della Milza nell \u2019Uomo\nVOL. IV.\ne in tutti gli Animali Vertebrati, Milano, 1803. Benj. Bush, An Inquiry into the Functions of the Spleen, &c., Philadelphia, 1806. Everard Home, On the Structure and Uses of the Spleen, Philos. Transact, for 1808, p. 45. ; further Experiments on the Spleen, p. 133. ; Experiments, &c., ibid. 1811. C. F. Heusinger, Ueber den Bau und die Verrichtung der Milz, Eisenach, 1817. F. Tiedemann und L. Gmelin, Versuche \u00fcber die Wege, auf welchen Substanzen aus dem Magen und Darm im Blut gelangen, \u00fcber die Verrichtung der Milz und die geheimen Haniwege, Heidelberg, 1820. T. Hodgkin, On the Uses of the Spleen, Edinb. Med. and Surg. Journ., 1822, p. 83. Dobson, Lond. Med. and Phys. Journal, 1830, Oct. G. C. Holland, Physiology of the Foetus, Liver, and Spleen, London, 1831. T. Muller, Ueber die Structur der eigenth\u00fcmlichen K\u00f6rperchen in der Milz einiger pflanzenfressender S\u00e4u-gethiere, M\u00fcll. Arch., 1834. T. C. H. Giesker, Spleno-logie, oder anatomisch-physiologische Untersuchungen \u00fcber die Milz, Z\u00fcrich, 1835. M. T. Evans, Lond. Edinb. and Dubl. Phil. Mag., 1833. Nov. Schwager-Bardeleben, Observations Microscopic\u00e6 de Glandularum Ductu Excretorio carentium Structura, &c. Berol. 1841. Th. v. Hessling, Untersuchungen \u00fcber die weissen K\u00f6rperchen der menschlichen Milz, Regenzburg, 1842. I. Reid, Lond. and Edinb. Monthly Journ., 1843. Apr. Fr. Oesterlen, Beitr\u00e4ge zur Physiologie des gesunden und kranken Organismus, Jena, 1843, pp. 41\u201452. E. Huschke, Lehre von den Eingeweiden und Sinnesorganen, Leipzig,\n1844.\tSchlemm, Berliner W\u00f6rterbuch der medicin. Wissenschaften, Band xxiii. Th. 435. Ch. Poelmann, Memoire sur la Structure et les Fonctions de la Rate, Annales et Bulletin de la Soci\u00e9t\u00e9 de M\u00e9decine de Gand, 1846, Dec. C. Handfield Jones, On the Yellow Corpuscles of the Spleen, Lond. Med. Gazette, 1847, Jan. John Simon, On the Thymus Gland, Lond.\n1845.\tA. Kolliker, Ueber den Bau und die Verrichtungen der Milz, in Mittheilungen der Z\u00fcricher naturforschenden Gesellschaft, 1847. A. Ecker; Ueber die Ver\u00e4nderungen welche die Blutk\u00f6rperchen in der Milz erleiden, in Zeitschrift f\u00fcr rationelle Medicin, Band vi. 1847. C. B. Heinrich, Die Krankheiten der Milz, Leipzig, 1847. T. Landis, Beitr\u00e4ge zur Lehre \u00fcber die Verrichtungen der Milz, Z\u00fcrich, 1847. Gerlach, Ueber die Blutk\u00f6rperchenhaltenden Zellen der Milz, in Zeitschrift f\u00fcr rationelle Medicin, Band vii. 1848. T. B\u00eaclard, Recherches exp\u00e9rimentales sur les Fonctions de la Rate et sur celles de la Veine Porte, Archives G\u00e9n\u00e9rales de M\u00e9-dicine, Paris, 1848, Oct. Nov. Dec.\n( Albert K\u00f6lliker.') *\nSTATISTICS, MEDICAL. \u2014 The Statistical Method; the Numerical Method. La M\u00e9thode Num\u00e9rique.\u2014 It is to be regretted that the use of numbers in any branch of scientific inquiry should have seemed to need a special name ; for the name has given rise to prejudices and misconceptions which could never have attached to the thing signified. There is no science which has not sooner or later discovered the absolute necessity of resorting to figures as measures and standards of comparison ; nor is there any sufficient reason why physiology and medicine should claim an exemption denied to every other branch of human knowledge. On the contrary, they belong in an especial manner to the class of sciences which may hope to derive the greatest benefit from the use of num-\n* The Editor is indebted to his friend Dr. Brinton, for the translation of the article on the normal anatomy of the spleen from the German MSS. of Professor K\u00f6lliker, and for the sketch of the abnormal anatomy,\n3 F","page":801},{"file":"p0802.txt","language":"en","ocr_en":"STATISTICS.\n802\nbers ; and even those persons who are most given to express doubts of the necessity or expediency of resorting to them, find themselves constrained to sanction by their own practice what they condemn in theory. This is an all-sufficient answer to those who content themselves with objecting in general terms to the employment of numbers in medical investigations. As to more minute and detailed objections, these will be found to be anticipated and disarmed by the simple consideration that they apply in reality not to the use, but to the abuse of numbers. The time has long gone by, when the absolute dependence of all science on observation and experiment could admit of question or dispute ; and, as no one in the present day claims for physiology and medicine any immunity from the severe conditions which the very nature of things imposes, we are spared those appeals to authority which might formerly have been required at our hands. The absolute necessity of observation and experiment towards the improvement of the science and art of medicine, in the widest acceptation of those terms, may, therefore, be safely taken for granted. The only points upon which any serious difference of opinion or divergence of practice exists, are the degree of care and accuracy which should be brought to bear on individual observations and experiments, the properties which fit single facts to be thrown into groups or classes ; the language which ought to be employed in expressing the general results of such classifications ; and the number of facts which, being so grouped or classified, may be required to establish a general proposition, or to furnish an accurate test or trustworthy standard of comparison.\nThe human mind is so constituted, that it looks forward to an occurrence with a confidence proportioned to the number of times that it has been previously known to happen. Hence, the universal belief that all living beings will die, and that the sun will rise and set to-morrow ; hence, the somewhat less sanguine expectation that quinine will cure ague, and that vaccination will either prevent or modify small-pox ; hence, the little hope we have that a severe attack of Asiatic cholera will terminate favourably, and our absolute despair of the recovery of a patient seized with hydrophobia. In these, and other analogous cases, we have either the experience of all mankind in all times and places, or that of large numbers of men in addition to our own. We do not require that the individual occurrences which have created our confidence, our misgiving, or our despair, should be committed to paper, arranged in columns, and embodied in sums or averages. For practical purposes we are satisfied with our own impressions. But should a doubt be expressed, and supported by a show of reason or experience, whether vaccination possess the virtue generally attributed to it ; should some new preventive measure or mode of treatment be recommended in cholera, as superior to other plans previously adopted ; we\nask for the specific facts which have seemed to warrant the doubts of the one party, and the recommendation of the other. If these facts are few, we naturally view them with mistrust, and are disposed to attribute them, at the best, to some coincidence ; or if, being more in number, their actual amount is stated in vague and general terms, we as naturally demand the precise figures. We feel instinctively, that common and familiar words are altogether wanting in precision ; that they take their meaning from the character of those who use them ; that, in a word, \u201c the sometimes of the cautious is the often of the sanguine, the alivays of the empiric, and the never of the sceptic ; while the numbers, 1, 10, 100, 1000, have but one meaning for all mankind.\u201d\nBut this mistrust of vague generalities of expression, is not the only form in which the more cautious and logical spirit of modern times embodies itself. The same misgivings are felt and expressed as to the propriety of committing the facts which are to serve as the materials of our theories to the uncertain keeping of the memory. We feel that a science built up of such materials, bears to true science the same sort of relation which tradition bears to historjr. It may not be destitute of valuable truths and sound principles, but it must fail in that precision and delicacy of discrimination which forms the peculiar attribute of true science as of true history. The history of medicine abounds with examples of important principles of treatment, and valuable remedies discovered solely by the light of experience, based upon the mere recollection of a number of individual occurrences. In this way the efficacy of bark and arsenic in ague, of mercury in syphilis, and of iodide of potassium in certain forms of secondary disease was discovered. Indeed, it may be confidently affirmed that all our knowledge of remedies is traceable to this source ; and it is probable that we shall continue to be indebted to it for all future discoveries of importance. It is the natural method of discovery, and, as such, will necessarily maintain its ground. But a very little reflection will convince us of the utter inadequacy of this method to meet the strict requirements of the science, and the ever-varying exigencies of the art of medicine. We may be able by its aid to sketch the broad outlines, and mark the salient points of a science, but we cannot hope to fill in the details with all the lights and shadows which go to make up the perfect landscape. Still less can we satisfy ourselves or others as to the real merits of disputed questions by an appeal to unwritten or loosely recorded experience. We all feel that there is no solution for our doubts short of an appeal to observations carefully and faithfully recorded, and summed up in the clear and simple language of figures. The use of mercury in syphilis, supplies us with an apt illustration of this truth. An experience, founded upon unrecorded and unnumbered occurrences, first recommended this remedy for the treatment of that disease ; but it would","page":802},{"file":"p0803.txt","language":"en","ocr_en":"STATISTICS.\n803\nappear that a counter experience of the same kind was continually leading to its disuse. Thus Morgagni tells us that, when he was quite a young man and went to Bologna, both methods of using mercury, internal and external, were so far deserted, that he never saw any physician make use of them, or ever heard of his using them, for the whole space of eight years, during which he studied there.* * * \u00a7 It would also appear that from the beginning of the sixteenth century up to the present time, there has always been a large number of surgeons, who have either abandoned the mercurial treatment altogether, or have restricted the use of the mineral to certain exceptional cases.f In the difference of opinion which prevailed upon this subject, the necessity of submitting the question at issue to the test of figures made itself so strongly felt, that a series of the most elaborate inquiries was undertaken at the instigation of governments, or by private individuals. These inquiries resulted in the collection of nearly 80,000 facts, by means of which the possibility of promptly healing venereal sores without mercury and with but moderate risk of a relapse, or of the occurrence of secondary symptoms, was conclusively established. % To this same test of figures, all the questions which arise from time to time, as to the relative value of the several remedies recommended in the treatment of syphilis are, by common consent, submitted. A most convincing proof that the numerical method is, in all cases of doubt and difficulty, the means of solution to which men naturally resort, is afforded by the treatise of Benjamin Bell, on this very subject, published in the year 1793.\u00a7 Speaking of the treatment of incipient chancres by caustic, he notices the very important objection, that the cure of the sores was often succeeded by buboes ; and he adds, that for a considerable time he was induced to suppose that the swellings of the glands, which thus take place after the cure of chancres, were more the effect of accident than of the method of treatment, and that they would have occurred under whatever management the sores might have been. The frequency, however, of their appearance, led him at last to suspect that he was mistaken, and further observation made it obvious that this was the case. He goes on to observe, \u201c As experiment alone could determine the question, I was resolved to employ this test. Of the first twenty patients who occurred with incipient chancres, in ten they were destroyed by an immediate and effectual application of lunar caustic, the remedy being employed, according to my usual custom at that time, instantly on my being called ; of the other ten, five were dressed with blue mercurial ointment, and five with common wax ointment. The sores to which caustic\n* Morgagni\u2019s 58th Epistle.\nf See on this subject, the British and Foreign Medical Review, vol. v. p. 4.\n+ British and Foreign Medical Review, vol. v. p. 7.\n\u00a7 A Treatise on Gonorrhoea Virulenta, and Lues Yenerea. By Benjamin Bell, vol. ii. p. 322.\nwere applied healed much sooner than the others, and next to them the sores that were dressed with mercurial ointment. But of the ten patients to whom caustic was applied, no less than eight had buboes, whilst only one bubo occurred in all the others; and it happened in one of the patients whose chancres had been dressed with mercury. I thought also that buboes appeared to be less frequent from the application of caustic, where mercury had been previously given. This fell within my observation from time to time, with patients who had taken mercury, either of their own'accord or by the advice of others ; and appearing to be of importance, I was resolved to bring it likewise to the test of experiment, and the result was as follows : of forty-eight patients with chancres in an incipient state, and exactly as they occurred in practice, one half was treated in the manner I have mentioned, by destroying the chancres with caustic immediately oil my being desired to see them, while all the others were put under mercury for eight or ten days before the application of caustic. In every other circumstance the method of treatment was the same. The difference, however, surprised me exceedingly. Of the twenty-four treated with the immediate application of caustic, twenty were seized with buboes; while only three buboes occurred in an equal number to whom mercury had been previously admin -istered.\u201d\nThe subject of the treatment of syphilis has been selected for illustration on account of the large use which has been made of figures in discussing the relative value of the two modes of treatment; and the extract from the works of Benjamin Bell as a proof that, long anterior to any discussions among medical men as to the value of the numerical method and the extent to which it might be applied in the solution of medical questions, men of shrewd common sense were driven to the use of numbers, as the natural and only means of solving difficult questions, and setting doubtful or disputed points at rest. Thus much, by way of introduction, the difference of opinion which prevails as to the value of the numerical method seemed to demand.\nThe numerical or statistical method may be defined as the science which prescribes rules for the bringing together of scattered observations, arranging them in classes, testing their sufficiency in point of number, and deducing from them, when so arranged, average and extreme results, fitted by their very condensation to become standards of comparison and data for reasoning.\nThe numerical method*, so defined and\n* The term, numerical method, will be used throughout this article in preference to the word statistics, or statistical method ; for, properly speaking, statistics means the science of states (from the German word staat, a state), and is therefore synonymous with the tenus \u201c political economy,\u201d \u201c political science,\u201d \u201c social science.\u201d The first use of the term statistics has been traced to Achenwal, Professor of Flistory in G\u00f6ttingen, who, in 1749, published an historical work, in which the phrase scientia statistica occurs for the first time. The use 3 p 2","page":803},{"file":"p0804.txt","language":"en","ocr_en":"STATISTICS.\n804*\nunderstood, comprises two distinct inquiries, the one relating to the individual facts which form the materials for the calculation of average and extreme values, and the other referring to the averages and extremes themselves. This natural and convenient division of the subject it is proposed now to adopt.\n1. Of facts considered as the elements of statistical inquiries.\u2014 Scientific inquiries are conversant with two orders of facts : \u2014 namely, phenomena of varying intensity, and events brought about by a multitude of causes. The first class of facts enters very largely into the science of physiology ; the last class constitutes, though not to the exclusion of the first, the mass of the materials by which the practical sciences of medicine and hygiene are built up.\nAs examples of phenomena of varying intensity may be cited the pulse and respiration, the temperature of the body, the secretions of the skin, kidneys, and lungs, the evacuations of the bowels, the weight and stature of the body at different ages, and the muscular development and power of different nations and classes of persons. These phenomena, carefully observed and recorded by the aid of the watch, the thermometer, the measure, the balance, and other instruments adapted to special purposes, become so many numerical values, having the same relation to the averages deduced from them, as the more simple events expressed in units bear to the mean results for which they furnish the materials.\nAs an example of an event bi'ought about by a multitude of causes may be mentioned the event of death, governed, as to the age at which it occurs, by original strength or peculiarity of constitution, good or bad nursing and management in infancy, sex, occupation and habits of life, climate and place of abode, skilful or unskilful treatment in sickness ; in a word, by the varied influences which make one man to differ physically from another. This is an illustration taken from the science of hygiene. The alternative of death or recovery from a disease induced by a cause or causes of variable intensity in persons of opposite sex and of different ages, with constitutions modified by the several agencies just specified, and submitted to different modes of treatment, is an example from the practice of medicine. Physiology furnishes illustrations of the same kind in those functions of the body (such as the eutting of the teeth, and the first appearance and cessation of the catamenia) which are dependent for\nof numbers as a necessary means of comparison in this work of Achenwal, led men to confound the instrument with the science. Dufau, in his Traite de Statistique, incorrectly derives the term statistics from the Latin status.\nThe meaning attached to the words statism and statist, in the writings of poets, essayists, and dramatists, bears out the view just put forward of the proper signification of the term statistics. Mil-ton, for instance, speaks of \u201c statists and lawyers,\u201d and elsewhere uses the term in the sense of a man having political power and influence. Ford also uses the word in this latter sense. South speaks of persons who called our religion statism.\nthe period of their occurrence on peculiarity of constitution determined by the combined action of the influences already adverted to.\nBetween these two orders of facts \u2014 phenomena of varying intensity, and events brought about by a multitude of causes \u2014 there is no other difference but that which is apparent on the face of each, namely, that each individual fact, in the one case, is represented by a variable number, while in the other it is a simple unit. If, for example, we count the pulse of several men at the same age, we shall find that each separate observation gives a different number ; but, the event of death or recovery in cases of typhus fever will be recorded as a simple unit. In all other respects the two classes of facts closely resemble each other; for the number of beats peculiar to the pulse of each individual, is as much the result of the concurrent action of several causes, as the event of death or recovery from fever. The original and acquired constitution, towards the formation of which so many causes must have conspired, determines the number of the pulse in the one case, and influences the event of the disease in the other. The two classes of facts are also equally fitted to supply the elements for the determination of average and extreme values; for it is obvious that the mean and extreme numbers of the pulse, in males and females respectively, furnish as trustworthy standards of comparison and data for reasoning, as the average number of men following different occupations who die before any specified period of life, and the greatest age which they respectively attain.\nFrom what has been just stated, it will be seen that all the facts which form the materials for our averages, are phenomena or events brought about by the concurrent action of a multitude of causes. The facts or events with which the physiologist and physician are conversant, are remarkable for the multiplicity of the causes which conspire to produce them. The subject of study is the human frame, with its differences of sex, age, and inherited or acquired constitution, acted upon by the variable influences of climate, occupation, and habits of life, and still further modified in disease by the treatment and regimen which may happen to be adopted. In consequence of the number and diversity of the influences brought to bear upon it, the human frame presents an object of study only less difficult than the human mind, affected by a like number and variety of moral causes, of which the true nature and force have to be unravelled by multiplied observations on the condition of mankind under different circumstances ; the aggregate of such observations constituting a great part of the science of statistics properly so called, and bearing to the practical science of government the same relation which pathology and therapeutics, based upon large collections of facts, do to the practice of medicine.\nNow this dependence of the individual facts or events with which physiology and medicine are conversant on the concurrent action of a","page":804},{"file":"p0805.txt","language":"en","ocr_en":"STATISTICS.\nmultitude of causes, has been urged as an objection to the introduction of the numerical method into the service of those sciences. It is admitted, that the use of numbers and averages by the astronomer who deals with the more simple relations of matter, such as magnitude and relative position, and by the engineer who avails himself of its more simple properties, such as its hardness, tenacity and elasticity, have contributed to make the science of the one perfect, and the art of the other safe ; but it is contended that the use of numbers cannot be extended beyond such narrow limits with safety or advantage, and that medicine and political economy lie beyond these limits. The actual practice of mankind, founded upon an instinctive perception of the necessity of employing figures in the service of the physician and statesman, may be fairly alleged as a sufficient answer to this objection ; but a little consideration will serve to show its futility.\nIn the first place, it is self-evident that the exclusion of figures from the service of medicine, does not bring about the disuse of those very facts and events which are objected to as unfit to be employed as statistical or numerical elements. The physician will still persist in stating and recording the results of his experience. He will still assert that he has sometimes observed this symptom in a certain disease, that he has often found that remedy beneficial, that he has almost never known such and such a mode of treatment to fail. Those who contend for the use of numbers in medicine, merely insist on the necessity of reducing the sometimes, the often, and the almost never to a more correct and intelligible form of expression ; and they argue that it is utterly inconsistent to object to the use of facts as materials or elements of numerical propositions, and yet not to censure the use of these same facts as foundations for loose and inaccurate verbal statements. From this dilemma there is obviously no escape. But, though the objection itself is futile, the misgiving of which it is the exaggerated expression is natural and well founded. It cannot excite surprise that the individual facts or events which own so many concurrent causes should be regarded as requiring, on the part of the observer, a greater degree of care in verifying, recording, collecting, and arranging them than would be necessary in the more simple cases already adduced ; and that both the facts themselves, and the numerical expressions in which they are embodied, should be viewed with a proportionate degree of distrust. From this moderate and reasonable view of the case, no advocate of the numerical method will be found to dissent. On the contrary, he will seek to strengthen it by giving due prominence to each separate ground of misgiving, and by laying down stringent rules for the guidance and governance of the observer. Before proceeding to detail some of these rules, it may be well to advert to a probable, and, indeed, obvious cause, of the distrust with which numerical data are sometimes regarded.\n805\nIndiscreet advocates of the numerical method have sought to apply the general results of collections of cases expressed in the language of figures to the treatment of individual cases of the same disease, without making allowance for those differences between case and case which confessedly existed in the collections themselves. They have used a general principle, as if it had been a rigid and unbending rule of action; forgetting that though, as the experience of assurance offices abundantly testifies, the general results obtained from a large number of individual facts may be safely reapplied to an aggregate of facts of the same nature, they cannot be brought to bear on a single case, or on a small number of cases, without the greatest danger. Each case must be viewed in practice, first as a generality governed by some large law of prognosis, diagnosis, and treatment ; and secondly, as a specialty demanding a careful consideration of all its peculiarities.\nAmong the rules which ought to govern the observer in the collection of facts destined to form the elements of averages, there are some of so simple and obvious a nature as to require no discussion. Such are, the previous preparation of some simple and available form of register, by means of which the several facts may be committed to paper at the very time of observation, so that nothing may be trusted to the memory ; the careful selection of the facts themselves ; the shaping of the inquiries which may be necessary to elucidate those facts as nearly as may be in the same terms ; the avoidance as much as possible of such leading questions as would be likely to bias the respondent, when the facts in question, like most of the particulars which make up the history of diseases, are dependent upon testimony ; and especially the purging of the observer\u2019s own mind of prejudices and preconceptions in respect of the subject of inquiry.\nThe careful selection of the facts which are to form the materials of our averages is by far the most important of these rules, and one which demands a little further consideration. If we consider the facts we are observing in the light of phenomena, or events brought about by a multitude of concurrent causes, it will be obvious that care will require to be exercised, not so much in verifying each phenomenon or event as that of which we are in search, as in ascertaining that all the concurrent causes or conditions are, or have been, in operation to bring about that phenomenon or event. The absence of a single cause or condition will vitiate the individual fact, and impair or destroy the value of our average results. A few illustrations will suffice to show what is here intended. We are anxious to determine the true average frequency of the pulse in adult males, in a state of rest, and as free as possible from the influence of all disturbing causes ; but, either from ignorance or oversight, we count it indifferently in every position of the body, and at all times of the day. In this case, our facts cease to be comparable facts ; for it is well","page":805},{"file":"p0806.txt","language":"en","ocr_en":"806\nSTATISTICS.\nknown, that both posture and time of day have a remarkable influence on the number of the pulse. Or, to take another case, we wish to ascertain the influence of some employment upon health (say that of the letter-press printer) ; but we overlook the important fact, that in every printing office, two or three very distinct occupations are carried on, of which the most important are those of the compositor and pressman. Not being fully aware of this fact, and of the wide difference existing between the tvro employments, we proceed to extract from some mortuary register the ages at death of printers as a class, calculate the average age at death, and then proceed to group the whole class of printers with that large class of occupations carried on in-doors, with little bodily exertion, to which the compositor alone properly belongs, but from which the pressman is, by the nature of his employment, excluded. In this case, we should have been misled by the common name borne by men following two really distinct occupations, and our facts would again cease to be comparable facts. A third and apt illustration is afforded by the Asiatic cholera. We wish to compare two different remedies or plans of treatment ; but we administer the one remedy, or adopt the one plan, at the onset of the epidemic, and the other during its decline. Here, again, our facts are not comparable facts ; for it is one of the well-known characteristics of this disease, that it is more severe on its first occurrence than during the period of its decline. The same sort of error would be committed, if one remedy were administered in an early, and the other in an advanced, stage of the attacks themselves. The principle which these illustrations are intended to enforce, is the necessity of selecting, as the elements of the same average, facts strictly comparable, or, in other words, brought about by the same combination of causes. Over the intensity with which each cause acts in individual instances, the observer can exercise no control. His province is to ascertain that the same combination of causes is at work to bring about each phenomenon or event. If from ignorance or oversight he fails in this duty, he impairs the value of his facts, and vitiates his inferences in proportion to the number and force of the conditions that he has overlooked or omitted.\nIn the observation and collection, therefore, of the individual phenomena or events which are to serve as materials for our average results, the first precaution to be observed is, that those phenomena or events should be strictly comparable as regards the combination of causes by which they are brought about ; or, as the French statists express it, we must ensure \u201c Vinvariabilit\u00e9 de Vensemble des causes possibles.\u201d The frequent omission of this most necessary precaution has given birth to the dogma of Morgagni \u2014 Non numerand\u00e6 scdpcr-jicndend\u0153 sunt observationes \u2014 and to the most valid objections urged against the application of the numerical method in medicine.\nFor the collection, arrangement, and classification of the facts which are to form the materials of our averages, no concise rules can be laid down. The tabular forms must adapt themselves to the exigencies of each individual inquiry ; and must be more or less complF cated as the subjects of investigation consist of few or many particulars. In reporting cases, for instance, and in collecting and analyzing those recorded by others, tabular forms embracing many particulars are required ; and the preparation of such forms demands unusual skill and care.* The same remarks apply to the collection and classification of recorded experiences and opinions bearing on particular subjects of inquiry f ; a numerical summary of authorities favourable and adverse to particular doctrines, constituting what may be not inaptly termed the statistics of opinion.\n2. Of the average and extreme results deduced from observation. \u2014 The observer having exercised all due care in the observation of his facts, having grouped together only those events which owned the same combination of antecedents or causes ; and having further correctly performed the work of enumeration, has thus obtained certain average and extreme results, which are to constitute standards of comparison and data for reasoning ; the question naturally arises \u2014 are these average and extreme results sound and trustworthy standards and data, or not ; and what are the circumstances which render them the one or the other ? Common sense and experience combine to give an authoritative answer to this question. Our average and extreme results are more or less sound and trustworthy, as the individual facts from which they have been calculated are more or less numerous. Where the facts upon which it is attempted to found a general principle, or to establish a standard of comparison, are very few, we are at once conscious of their insufficiency ; and the more readily when an attempt is made to apply the principle or standard in question to some important practical purpose. A better illustration of the futility of such an attempt can scarcely be found than the well-known test of Ploucquet. That author proposed to determine whether or not a child w\u2019as still-born by referring every doubtful case to a standard of comparison, founded upon three observ-\n* On this subject the late Dr. Todd, of Brighton, has written a very able work, which may he safely recommended to all who desire to enter upon such complicated investigations. The title of this work is : \u2014 The Book of Analysis, or a New Method of Experience, whereby the Induction of the Novum Organon is made easy of Application to Medicine, Physiology, Meteorology, and Natural History ; to Statistics, Political Economy, Metaphysics, and the more complex Departments of Knowledge. By Tweedy John Todd, M.D., of the Royal College of Physicians of London, &c. &c.\t1831.\nt Reference may here be made to a paper published in the 3rd volume of the Journal of the Statistical Society of London, \u201c On the best Method of Collecting and Arranging Facts, with a proposed New Plan of Common- Place Book.\u201d By the Author of this Essay.","page":806},{"file":"p0807.txt","language":"en","ocr_en":"STATISTICS.\t807\nations of the relative weight of the lungs and body ; of which three observations, one was made upon the body of an immature infant, so that the subjects of the observations were not strictly comparable. Though Ploucquet, in this procedure, offended against two of the most obvious statistical rules, his test continued to be treated with undeserved respect, till comparatively recent investigations on a larger scale had demonstrated the little reliance to be placed upon it.\nThe most common attention to the ordinary daily occurrences of life would suffice to caution us against such errors as that into which Ploucquet fell. Coincidences of the most startling character are constantly happening to put us on our guard against them. One which occurred to the writer of this article deserves to be put on record. Two cases of congenital absence of the larger pectoral muscle on the same side of the body, occurred, on the same day, among the outpatients of the King\u2019s College Hospital* This defect he has never happened to observe within the wards of that Hospital or elsewhere, either before or since. A similar coincidence, though of a less striking character, presented itself in the same institution while the writer was noticing with some care and interest the complexion and physiognomy of patients suffering from pulmonary consumption. His own previous experience, in conformity with the general opinion, had pointed out the fair complexion as that of the great majority of phthisical patients ; but the almost exclusive occurrence for several days together of the olive complexion, among patients labouring under that disease, had almost led him to discard his former opinion and that of the best authorities, and to embrace one which, as farther observation convinced him, would have been erroneous.\nGames of chance are constantly furnishing striking examples of these coincidences, in the shape of what is familiarly known as a run of good or ill-luck ; the same event, favourable or unfavourable, occurring many times in succession, contrary not only to reasonable expectation, but to the results of unerring calculation. On the other hand, the success of the bank, with only a slight calculated chance in its favour, but with a capital sufficiently large to await the inevitable change in the run of luck, vindicates the sufficiency of large numbers of facts. The great annual fluctuations, too, which take place in the balance of the receipts and expenditure of assurance offices, but the ultimate safety of their transactions, when extending over a long term of years and embracing a large number of insurances, serve to enforce the same truth.\nThe sufficiency for all practical purposes of large numbers of facts, may also be inferred from the remarkable uniformity observed to take place in the annual summaries of events brought about by the continued operation of the same combination of causes. The annual reports of the Registrar-General supply many illustrations of this principle. The illustration\nbest suited to our present purpose, is one drawn from an event removed, by the very nature of the case, beyond the reach of external influences, or only very remotely and indirectly amenable to them ; namely, the proportion of male and female births in successive years. In the eighth annual report of the Registrar-General (p. lxi.), a table is given, in which the number of males and females born, to every hundred living males and females respectively, is recorded for the seven years 1839-45. If we substitute 100,000 for 100, the table will read thus.\nYear.\tMales.\tFemales.\tExcess of Males.\n1839\t6,498\t6,211\t287\n1840\t6,539\t6,250\t289\n1841\t6,580\t6,289\t291\n1842\t6,564\t6,273\t291\n1843\t6,597\t6,305\t292\n1844\t6,676\t6,381\t295\n1845\t6,622\t6,329\t293\nThe largest excess of male over female births, therefore, in these seven years is 295, and the least 287, the average being 291 ; so that the extreme fluctuation amounts to only 8 births in about 6500, or considerably less than 1 in 800 ; while the excess or defect above or below the average of 291 is only 4 births, or less than l in 1600. If the causes which determine the births of males and females respectively could be assumed to be constant and uniform, these fractional fluctuations would express the divergences due to the insufficiency of the number of observations to express an absolutely true result. The close approximation actually obtained must be held to prove the sufficiency for every practical purpose of results based upon large numbers of observations.\nHaving thus shown, by two opposite examples, the total insufficiency of small numbers of facts, and the sufficiency, at least for practical purposes, of large numbers of observations, it will be necessary to enter into a more detailed examination of the relative value of numbers of observations intermediate between these two extremes.\nFrom what has been already stated, it must be obvious that the degree of confidence to be reposed in results based upon different collections of facts must vary with the number of those facts ; and that, other things being equal, the value of the results must increase with every addition made to that number. But it is only by actual observation, or by mathematical calculations based upon indisputable data, that the precise value of any particular number of facts can be determined. Observation, indeed, is altogether unequal to give more than a vague and general idea of the relative values of small and large collections of facts ; so that we must ultimately resort to the mathematics both for authoritative decisions and safe guides. As, however, the large majority of mankind is destitute of that mathematical knowledge and 3 F 4","page":807},{"file":"p0808.txt","language":"en","ocr_en":"808\nSTATISTICS.\ntraining which is essential to the appreciation of mathematical rules, it is desirable to show, by an appeal to the results of actual observation, the increasing value of increasing collections of facts, as well as the rate of that increase. For this purpose, it is proposed to make use of some observations collected by the writer of this article. Having had occasion, a few years since, to bring together, from the pages of* the Peerage and Baronetage, the ages at death of the male members of the English aristocracy, dying 21 years and upwards, to the number of several hundreds, it appeared to be a favourable opportunity of testing the relative values of large and small numbers of facts, as well as of obtaining a rude approximation to a rule or measure of value. The ages at death, relating, as they do, to members of the same class in society, and taken without selection from the successive obituaries of noble families, constitute a collection of strictly comparable facts, well suited to the purpose in view. The following table, which embodies the results of these facts in their bearing on the question before us, has been formed in the following manner : \u2014 The several facts were first arranged in groups of 25 each; two successive groups of 25 were then formed into groups of 50 ; the groups of 50, in like manner, into groups of 100, and so on, till the last totals in the table were obtained. The greatest and least averages obtained from each group of facts were then selected, and, with the range, or difference between them, thrown into a tabular form.\nNumber\tAverage Age at Death.\t\t\n. of Facts.\tMax.\tMin.\tRange.\n25\t69-40\t50-64\t18-76\n50\t66-44\t55-20\t11-24\n100\t63-70\t56-85\t6-85\n200\t62-38\t57-61\t4-77\n400\t61-10\t58-24\t2-86\n800\t60-84 V\t59-67 J\t1*17\n1600\t60*25\t\t\nNow -, if we assume the true average duration of life among the members of the Peerage and Baronetage, who have attained their 21st year to extend to 60 years (being the mean of 1C00 observations), and, for the sake of simplicity, substitute for the decimals in the table the whole numbers nearest to them in magnitude, it will follow that, in making use of the several groups of observations specified\nNumber of Facts.\tError in Excess or Defect.\n25\t9 V\n50\tsi\n100\t3*\n200\tn\n400\tu\n800\t0 k\nin the first column of the annexed table, we may have the errors in excess or in defect which are enumerated in the second column.\nThese figures, then, represent the extreme error which could have been committed, in this particular case, by relying on 25, 50, 100, 200, 400, and 800 facts respectively. But it must be borne in mind, that this collection of facts is one which, from the very nature of the case, is likely to present a minimum of divergence between the averages deduced from the same number of facts ; for the several obituaries, from which the ages at death are taken, register the deaths of one and the same class, inhabitants of the same country, and split into family groups bearing a close resemblance to each other. If, instead of a single class, exposed to similar influences, and not admitting of subdivision into smaller classes, we were to take the members of that large section of the community which is generally known as the upper and middle class, with their numerous subdivisions of employment, and class them by fifties and hundreds, we should encounter a much more considerable divergence. The results of such a comparison for the class in question are embodied in the following table.\nNumber\tAverage Age at Death.\t\t\nof Facts.\tMax.\tMin.\tRange.\n50\t84-44\t56-78\t27-66\n100\t76-24\t58-25\t17-99\n200\t73-54\t61-50\t12-04\n400\t69-78\t63-51\t6-27\n800\t68-67\t65-07\t3-60\n1600\t67-93\t64-84\t3-09\n3200\t66-38 v\t\t65-82 y\t0-56\n6400\t66-10\t\t\nIf, as in the former case, we take 66 years to be the true average age attained by the entire middle class, reckoning from 21 years of age, and reduce the range in each case to the nearest whole number, we shall have the following divergences.\nNumber of Facts.\tError in Excess or Defect.\n50\t14\n100\t9\n200\t6\n400\t3\n800\t2\n1600\tH\n3200\t0*\nIn this instance, therefore, though we begin with 50 in place of 25 facts, we obtain a possible error in excess or defect of 14 years in place of 9J years. It must be obvious, then, that the errors to which averages deduced from any given number of facts are liable, will vary with the nature of those facts ; and that the extent of possible error will bear","page":808},{"file":"p0809.txt","language":"en","ocr_en":"STATISTICS.\n809\na certain proportion to the number of the influences which are brought to bear on each unit of each collection of facts.\nIt must not, however, be forgotten that the figures in these several tables represent only possible errors. It may happen that the first 25 observations brought together may yield an average differing by less than a single unit\nfrom the mean of thousands of observations ; and there is always a balance of probability in favour of the average even of a small number of facts approximating more closely to the true average than to the extremes. That this is the case will be evident on the most cursory inspection of the following tables, of which the first is founded upon the facts\nAverage Age at Death.\t25 Facts. 72 Groups.\t50 Facts. 36 Groups.\t100 Facts. 18 Groups.\t200 Facts. 9 Groups.\t400 Facts. 4 Groups.\t800 Facts. 2 Groups.\n69\t1\t\t\t\t\t\n68\t0\t\t\t\t\t\n67\t0\t\t\t\t\t\n66\t3\t1\t\t\t\t\n65\t4\t0\t\t\t\t\n64\t9\t2\t1\t\t\t\n63\t3\t3\t1\t\t\t\n62\t3\t5\t3\t3\t\t\n61\t9\t6\t3\t0\t3\tI\n6\u00a9\t9\t4\t3\t2\t0\t1\n59\t8\t5\t3\t3\t0\t\n58\t6\t5\t1\t1\t1\t\n57\t5\t1\t3\t\t\t\n56\t6\t3\t\t\t\t\n55\t1\t1\t\t\t\t\n54\t3\t\t\t\t\t\n53\t1\t\t\t\t\t\n52\t0\t\t\t\t\t\n51\t1\t\t\t\t\t\nAverage Age at Death.\t50 Facts. 128 Groups.\t100 Facts. 64 Groups.\t200 Facts. 32 Groups.\t400 Facts. 16 Groups.\t800 Facts. 8 Groups.\t1600 Facts. 4 Groups.\t3200 Facts. 2 Groups.\n84\t1\t\t\t\t\t\t\n83\t0\t\t\t\t\t\t\n82\t0\t\t\t\t\t\t\n81\t0\t\t\t\t\t\t\n80\t0\t\t\t\t\t\t\n79\t0\t\t\t\t\t\t\n78\t0\t\t\t\t\t\t\n77\t0\t\t\t\t\t\t\n76\t1\t1\t\t\t\t\t\n75\t1\t0\t\t\t\t\t\n74\t4\t1\t1\t\t\t\t\n73\t2\t1\t0\t\t\t\t\n72\t2\t1\t0\t\t\t\t\n71\t5\t0\t0\t\t\t\t\n70\t4\t4\t0\t1\t\t\t\n69\t7\t3\t2\t0\t1\t\t\n68\t13\t5\t3\t1\t0\t1\t\n67\t17\t9\t4\t4\t1\t0\t\n66\t20\t13\t14\t4\t2\t1\t2\n65\t5\t13\t2\t4\t3\t2\t\n64\t16\t6\t2\t2\t1\t\t\n63\t11\t1\t2\t\t\t\t\n62\t10\t4\t1\t\t\t\t\n61\t3\t1\t1\t\t\t\t\n60\t3\t0\t\t\t\t\t\n59\t0\t0\t\t\t\t\t\n58\t0\t1\t\t\t\t\t\n57\t3\t\t\t\t\t\t","page":809},{"file":"p0810.txt","language":"en","ocr_en":"STATISTICS.\n810\nrelating to the duration of life of the aristocracy, and the second on the facts relating to the duration of life of the combined upper and middle classes. For the sake of perspicuity, the average of all the facts in either table is distinguished by a larger type.\nThese tables speak for themselves. In the first table, for instance, the small number of 25 facts is seen to yield the same average as the total of 1800 facts in no less than 9 instances, or one eighth of the whole number ; while in 26 out of 72 instances, or more than one third, the average of 25 facts exceeds or falls short of the average of 1800 facts by only a single unit. In like manner, it appears from the second table, that in 20 cases out of 128, or little less than one sixth, the average of 50 facts coincides with that of 6400 facts ; and that in 42 out of 128, or nearly one third, it differs from it only by a single unit. Without entering into a minute examination of the other columns of the two tables, it will suffice to state that the probability in favour of an average of a given number of observations coinciding with the true average increases with the number of observations ; so that we are again brought back to the expediency of collecting large numbers of observations wherever it is practicable so to do. In using small numbers of facts to establish data for reasoning or standards of comparison, we are bound to speak with diffidence of their sufficiency, and we ought to regard them rather in the light of probabilities requiring to be strengthened by other probabilities, as weak arguments require to be supported by additional reasons, than as, in themselves, worthy of great reliance. According to this view of the case, we are not precluded from the use of averages drawn from small numbers of facts. The employment of such averages with this proviso is an absolute scientific necessity ; for in many instances we are prevented by causes too numerous to specify from bringing together facts by the hundred or the thousand, and yet, were we to reject the smaller numbers as inadmissible, we should be thrown back upon the still more loose and less trustworthy general statements from which it is the province of statistics to rescue us.\nAn examination of the two foregoing tables, as well as of those which display the extreme variations between the averages derived from the same numbers of facts, will serve to prove the hopelessness of any attempt to establish by observation rules for measuring the relative value of averages derived from different numbers of facts. It must be equally evident that no deductions drawn from observation can enable us to state the actual liability to error of any given number of facts, considered as facts, without reference to their peculiar nature. To determine this liability to error belongs solely to the mathematics.\nIf, on the one hand, observation is unable to supply us with the means of testing the true liability to error of conclusions based on\na given number of facts, considered as facts, without reference to their peculiar nature, it must be evident, on the other hand, that mathematical formulae deduced from abstract reasoning can only supply us with the means of measuring the value of a given number of facts in this their abstract relation, without taking into account the varying quality of the facts themselves. But as it is of the utmost importance to be able to test the abstract sufficiency of a given number of facts to establish a principle or to supply a sound standard of comparison, it will be necessary to enter at some length into this part of our subject.\nThe facts already adduced, must have abundantly shown that the limits of deviation from a true average result are wider or narrower as the number of facts from which the average is drawn is smaller or greater. Many eminent mathematicians, and M. Poisson among the number, have laboured to convert this general principle into an exact numerical expression or formula, applicable as a test of the true value of larger or smaller collections of facts, and as an exact measure of the limits of variation. M. Gavarret, in his work on Medical Statistics, contends successfully for the introduction of these formulae into the service of the medical man ; and adopting the sentiment of Laplace, \u201c Le syst\u00e8me tout entier des connaissances humaines se rattache \u00e0 la th\u00e9orie des probabilit\u00e9s,\u201d he insists that medical statistics, or, as we prefer to term it, the Numerical Method, applied to medicine, is nothing more nor less than a special application of the Calculus of Probabilities, and the Theory of large Numbers ; and that as such it is the most indispensable complement of the experimental method. In other words, he deems it incumbent on the medical man to apply to his numerical results the corrections supplied by the formulae of the pure mathematics ; and before he concludes that any number actually obtained by observation is a true representative of a fact or law, to determine whether that number may not be comprised within the limits of possible variation. M. Gavarret illustrates the necessity of this precaution by applying his mathematical formulae to a great variety of results based upon observation ; but he especially insists upon bringing the alleged efficacy of certain modes of treatment to this searching test. The most convenient course to adopt, in reference to these formulae, will be to present the calculations based upon them in tabular forms, and then to apply these calculations to one or two striking examples.\nThe following table presents at one view the possible errors corresponding to average mortalities deduced from different numbers of observations. It is obvious that the table is equally applicable to other contingencies of the same kind, where one of two events is possible in every instance. The mode of using it will be presently explained and illustrated.","page":810},{"file":"p0811.txt","language":"en","ocr_en":"STATISTICS.\t811\nTable of the possible Errors corresponding to Average Mortalities deduced from different Numbers\nof Observations.*\nNumber of Observations.\tAverage Mortality by Observation.\tNumber of Deaths.\tNumber of Recoveries.\tPossible Error.\tNumber of Observations.\tAverage Mortality by Observation.\tNumber of Deaths.\tNumber of Recoveries.\tPossible Error.\n25\t0-200000\t5\t20\t0-226274\t500\t0 300000\t150\t350\t0-057965\n50\to-iooooo\t5\t45\t0-120000\t500\t0-350000\t175\t325\t0-060333\n50\t0-200000\t10\t40\t0160000\t\t\t\t\t\n50\t0-300000\t15\t35\t0-183302\t600\to-iooooo\t60\t540\t0-034641\n\t\t\t\t\t600\t0-150000\t90\t510\t0-041231\n100\t0-100000\t10\t90\t0-084852\t600\t0 200000\t120\t480\t0-046188\n100\t0-150000\t15\t85\t0-100994\t600\t0-250000\t150\t450\t0-050000\n100\t0-200000\t20\t80\t0-113136\t600\t0-300000\t180\t420\t0-052915\n100\t0-25C000\t25\t75\t0-122474\t600\t0-350000\t210\t390\t0 055077\n100\t0-300000\t30\t70\t0-129614\t\t\t\t\t\n100\t0-350000\t35\t65\t0-134906\t700\t0-100000\t70\t630\t0-032071\n\t\t\t\t\t700\t0-150000\t105\t595\t0038173\n200\to-iooooo\t20\t180\t0060000\t700\t0 200000\t140\t560\t0-042762\n200\t0-150000\t30\t170\t0-071414\t700\t0-250000\t175\t525\t0-046291\n200\t0-200000\t40\t160\t0-080000\t700\t0-300000\t210\t490\t0-048990\n200\t0-250000\t50\t150\t0 086602\t700\t0-350000\t245\t455\t0-050990\n200\t0-300000\t60\t140\t0-091650\t\t\t\t\t\n200\t0-350000\t70\t130\t0-095392\t800\to-iooooo\t80\t720\t0-030000\n\t\t\t\t\t800\t0 150000\t120\t680\t0 035707\n300\to-i 00000\t30\t270\t0-048990\t800\t0-200000\t160\t640\t0-040000\n300\t0-170000\t45\t255\t0 058309\t800\t0-250000\t200\t600\t0-043301\n300\t0-200000\t60\t240\t0-065320\t800\t0-300000\t240\t560\t0045826\n300\t0-250000\t75\t225\t0 070711\t800\t0 350000\t280\t520\t0 047697\n300\t0 300000\t90\t210\t0-074833\t\t\t\t\t\n300\t0-350000\t. 105\t195\t0-077889\t900\t0 100000\t90\t810\t0 028284\n\t\t\t\t\t900\t0-150000\t135\t765\t0 033665\n400\t0-100000\t40\t360\t0-042426\t900\t0 200000\t180\t720\t0-037712\n400\t0*150000\t60\t340\t0-050497\t900\t0-250000\t225\t675\t0 040825\n400\t0-200000\t80\t320\t0-056568\t900\t0-300000\t270\t630\t0 043205\n400\t0-250000\t100\t300\t0-061237\t900\t0-350000\t315\t585\t0 044969\n400\t0-300000\t120\t280\t0-064807\t\t\t\t\t\n400\t0-350000\t140\t260\t0-067454\t1000\t0 100000\t100\t900\t0 026833\n\t\t\t\t\t1000\t0150000\t150\t850\t0-031937\n500\t0-100000\t50\t450\t0-037947\t1000\t0-200000\t200\t800\t0-035777\n500\t0150000\t75\t425\t0 045167\t1000\t0-250000\t250\t750\t0-038730\n500\t0-200000\t100\t400\t0 050596\t1000\t0-300000\t300\t700\t0 040988\n500\t0-250000\t125\t375\t0054772\t1000\t0-350000\t350\t650\t0-042661\nThe use of this table will be best explained by an example. Let us suppose that a medical man, having, for a long time, adopted a particular course of treatment in a certain malady, has arrived at the following results :\n120 deaths, 680 recoveries, 800 cases.\nThe average mortality in this case would\n* This table is an abbreviation of one given at p. 142. of Gavarret\u2019s work, but with additional calculations based on the same formula, for the numbers from 25 to 200 inclusive. The formula from which the figures in the column of possible errors have been calculated is,\ny 2 . m . \u00bb\nin which m represents the number of times that an event a has happened, n the number of times that an event b has happened, and ju. the total number\nof events : so that m + n \u2014 fi; m the average fre-\nquency of the events m,as obtained by observation ; and tn +\t/2.m.nan\u00f9^_\t/2.m.n\nfA 2*V fi-2\tm ^'V\t/it,3\nthe limits within which the true average,as corrected by the formula, lies.\nbe or 0-150000 (see the second column of the table for 800 facts and 120 deaths). At first sight the medical observer would appear to be justified in asserting that under his method of treatment the mortality was at the rate of only 150,000 in 1,000,000 patients, or 15 per cent. But this assertion would be immediately met by the objection that the number of facts is not sufficient to justify this statement, that an average deduced from so small a number as 800 facts can only be received as an approximation to the truth, and that it requires to be corrected by the aid of the figures in the table.\nAccordingly, on referring to the column of possible errors corresponding to 800 cases and 120 deaths, we find that the error in excess and defect to which this number of facts is liable, amounts to 0\u2018035707, which error must be added to and taken from the O'150000, the result of actual observation. It follows, therefore, that the true result must be somewhere between the numbers\n0-150000 added to 0-035707, or 0-185707, and 0 150000 dim. by 0*035707, or 0-114293,","page":811},{"file":"p0812.txt","language":"en","ocr_en":"812\nSTATISTICS.\nSo that instead of asserting, as we should seem justified in doing, that the mortality under the influence of the treatment adopted amounted to 15 per cent., we could only claim a mortality comprised between the numbers\n185,707 and 114,293 in 1,000,000 cases: or approximatively between the numbers, 19 and 11 per cent.\nUncorrected observation, therefore, would give, as the result of the treatment adopted, 15 per cent., while corrected observation would give some number between 19 and 11 per cent.\nThe application of the formula given in the note to an actual case will be more instruc-\ntive than an imaginary example.\nM. Louis, in his Recherches sur la Fi\u00e8vre Typhoide, has attempted to illustrate the treatment of typhus fever, by minutely analysing 140 cases. The result was as follows : \u2014 Number of deaths (m) 52 Number of x-ecoveries (n) 88 Total\t-\tO) 140.\nThe mortality in these cases was therefore or 0 37143 ; and if we were to take this mortality as the strict expression of the results of the treatment adopted, we should shape our proposition as follows:\u2014The mortality of typhus fever, under the treatment adopted by M. Louis, amounted to\n37,143 deaths in 100,000 patients ; or, in round numbers,\n37 deaths in 100 patients If, now, we proceed by means of the formula referred to, to determine the possible error attaching to this proposition (i. e. to the number of facts upon which it is made to rest),\nwe find it to be equal to 2/2. m.n 2 /2.52.88\t_ \u00c4\n\\/\t^\t~ \\/ (140)3 \u2014 \u00b0'11550*\nThis being the possible error in excess and defect, the true influence of the treatment will be comprised between the following limits : \u2014\n-+ 2/jL\u2122^_0.37 i43+o-l 1550=0-48693 M V F3\nand\n2 /^^=0-37143-0-11550=0-25593. V- V ^\nThus all that we really learn from this record of experience is, that, under the treatment adopted, the number of deaths may vary between\n48,693 and 25,593 in 100,000 patients, or approximatively between 49 and 26 in 100 patients.\nIn other words, if we were to employ the same mode of treatment in a great number of cases of typhus fever, we might lose any number between about a fourth and a half of our patients.*\nThe same formula is equally applicable to the solution of doubtful questions relative to the results of two or more series of facts which\n* Gavarret, Principes G\u00e9n\u00e9raux de Statistique M\u00e9dicale, p. 284.\nwe are desirous of comparing. It may happen that the difference between the average result of one series of facts and that of a second series, is so inconsiderable, as to leave us in doubt whether it may not be explained by a reference to the limits of error to which the number of facts in either return is liable.*\nIt often happens, that the average results of two series of observations relating to two alternative events (such as the events of death or recovery in particular diseases, the birth of a male or female child, &c.) approximate so closely, that we are at a loss whether to attribute the slight difference existing between the two averages to coincidence, or to the operation of certain efficient causes. If the number of observed facts be small, the difference between the averages derived from the two series of facts may be so slight as to fall short of the difference between the limits of error in excess or defect. The same result may also happen with any number of facts, however considerable. In order to solve the doubts which necessarily attach to such close approximations, a mathematical formula has been brought into requisition, and employed in the formation of tables applicable to this purpose. Such a table is subjoined. The mode of applying it will be presently explained.\nThe use of this table will be understood from the following example : \u2014 In the six years 1839-44 there occurred in England, on the average of those years, 515,478 births, of which 264,245 were males, and 251,233 females. As the difference between these two numbers is not very considerable, a question might arise, whether that difference is not compatible with the error in excess to which half a million of facts is liable. The use of the formula on which the foregoing table is founded, would at once clear up this doubt.\n264,245 male births in a total of 515,478, is equal to\n512,904 male births in 1,000,000 births. But, on the supposition that the male and female births are really equal in number, we have the limits of variation equal to 500,000\n+ A / \u2014--------and 500,000\u2014A /\u2014\nA/ 515478\tA/ 515478,\nor 500,000-(- 000,624 and 500,000\u2014000,624, or a maximum of 500,624, and a minimum of 499,376. The difference by the formula is, therefore, 1248 in the million, while the observed difference between the highest and lowest number of male births occurring in the six years 1839-44, is 514,809\u2014511,781, or 3,028. The inference, therefore, is irresistible, that the excess of male births is due to some efficient cause or causes, and that it is not merely an error to which the number of half a million of facts is inevitably exposed.j-\n* For illustrations of this application of the foregoing table, and of the formula fromwhich the figures are calculated, see Gavarret\u2019s Statistique M\u00e9dicale, p. 80. et seq., and notes, p. 274.\nf Several applications of this table and of the formula from which the figures are derived, will be","page":812},{"file":"p0813.txt","language":"en","ocr_en":"STATISTICS.\t813\nTable of the Limits of Variation compatible with an equal Chance relative to two observed Events.*\nNumber of Cases.\tLimits of Variation.\t\n100\t0 641429\t0*358571\n150\t0-615470\t0-384530\n200\t0-600000\t0-400000\n250\t0-589442\t0-410558\n300\t0-581650\t0-418350\n350\t0-575593\t0-424407\n400\t0-570711\t0-429289\n450\t0-566667\t0*433333\n500\t0-563246\t0-436754\n550\t0-560302\t0-439698\n600\t0-557735\t0-442265\n650\t0-555470\t0-444530\n700\t0-553452\t0-446548\n750\t0-551640\t0-448360\n800\t0-550000\t0 450000\n850\t0-548507\t0-451493\n900\t0-547140\t0-452860\n950\t0-545883\t0-454117\n1000\t0-544721\t0-455279\n1100\t0-542640\t0-457360\n1200\t0*540825\t0-459175\n1300\t0-539223\t0-460777\n1400\t0-537796\t0-462204\n1500\t0-536515\t0-463485\n1600\t0-535355\t0-464645\n1700\t0-534300\t0-465700\n1800\t0-533333\t0-466667\n1900\t0-532444\t0-467556\n2000\t0-531623\t0 468377\n2500\t0-528284\t0-471716\n3000\t0-525820\t0-474180\n3500\t0-523905\t0-476095\n4000\t0*522361\t0-477639\nProvision having been thus made by the two preceding tables for testing the sufficiency of average results based upon different numbers of facts relating to two alternatives, and determining the possible variation or limits of error to which the numbers of facts in question, considered simply as facts, without regard to their peculiar nature, are liable, provision still remains to be made for testing in like manner the value of those averages, which belong especially to the domains of ph} siology and hygiene, namely, the average number of the pulse and respiration, the average age at death of different classes of the community, &c. In the absence of tables specially adapted to this purpose, it must\nfound in the work of Gavarret, so often quoted, from p. 143. onwards, and in the notes at p. 286. et seq.\n* The formula employed in the construction of this table is\n0-50 \u00b1/-\n** A\nwhere p, as before, represents the total of the observed facts. The table will be found at greater length at p. 230 of Gavarret\u2019s work on Medical Statistics.\nsuffice to state, in general terms, that the averages derived from a given number of facts are not to be regarded as strict expressions of the truth, but as approximations more or less remote, as the number of facts is less or more considerable.\nBut a very important question here arises :\n\u2014\tTo what extent, and under what restrictions, do calculations based on mathematical formulae and derived from abstract reasoning, admit of application to the results of actual observation? Conceding, as we may safely do, the soundness of the formulae, there is yet great room to doubt the propriety of their application to the average results of observation. For if we suppose a mathematical formula to be applied successively to a long series of averages derived from the same number of facts, it must obviously administer a similar correction to those averages which happen to coincide with the true average, and to those which lie at the two extremes. This consideration is sufficient in itself to condemn the use of mathematical formulae, except as a means of exhibiting in a striking light the possible error attaching to a small number of facts, considered abstractedly as facts.\nFrom the foregoing considerations, then, it would seem to follow, that although averages derived from small numbers of facts are subject to a considerable amount of possible error, there is always such a probability of their coinciding with, or not differing widely from, the true averages, as to justify their employment as standards of comparison and data for reasoning. At the same time it must be conceded, that averages derived from small numbers of facts stand in need of a confirmation which averages drawn from larger numbers of facts do not require, and that in using the former we are bound to speak with a reserve proportioned to the scantiness of our materials.\nOf extreme values derived from observation.\n\u2014\tAs averages founded upon large numbers of facts are numerical expressions of true probabilities, so extreme values are expressions, in the same precise language, of possibilities. Both orders of facts have their scientific and practical applications ; but those applications which belong to the extreme values have been less attended to than those which pertain to averages.\nOne obvious use of extreme values is to confirm and strengthen the conclusions drawn from averages. Thus, if we wish to ascertain the relative duration of life of two classes of persons, we rnay make use of the greatest age attained by either class in confirmation of tho mean of all the observations ; and the coincidence of the one with the other will give increased confidence in the general result.\nAnother important use of extreme values is as a test of numerical theories. Two apt illustrations of this application of figures are afforded by that practical science which deals most largely in possibilities \u2014 Forensic Medicine. M. Orfila, in his \u201c Trait\u00e9 des Exhumations,\u201d states that it is possible to determine","page":813},{"file":"p0814.txt","language":"en","ocr_en":"814\nSUBCLAVIAN ARTERIES.\napproximative^ the stature of the skeleton and of the body by measuring one of the cylindrical bones; but instead of testing the value of this conclusion by making use of the extreme values, he contents himself with a rough average. It appears, however, that if we take several cylindrical bones having the same length, and compare them with the corresponding ascertained stature of the skeleton, the extreme statures are very wide apart. Of seven ulnas, for instance, having each the same length (viz. 10 inches, 8 lines), one corresponded to a stature of 6 feet 1J inch, and another to a stature of only 5 feet 5 inches. The difference of 8\u00a3 inches shows the possible error which might be committed by trusting to this standard of comparison, and demonstrates its futility.\nThe other illustration is afforded by the well-known test of the absolute weight of the foetal lungs. It used to be laid down as a rough average that in still-born mature children the weight of the lungs was one ounce, and in children that were born alive two ounces. More accurate observation showed that this rough guess was very far from the truth. It was only, however, by the aid of extreme values that the utter worthlessness of this test could be proved. It resulted from the collation of a moderate number of observations that the lowest weight before and after respiration were the same to an unit, while the greatest weight of the lungs of stillborn children, in two instances, surpassed the greatest weight of the lungs of children born alive. Nothing could more clearly demonstrate the insufficiency and invalidity of this test.\nThe same general principle which applies to averages applies also to the extremes, namely, that the value of the extremes increases with the number of observations from which they are selected. It is obvious, however, that a larger number of facts will be required to arrive at a true extreme value than to obtain a close approximation to the true mean : 10,000 facts, for instance, may give a true mean duration of life for the inhabitants of any country ; but as many millions may not happen to embrace the greatest attainable\nThe same principles, then, apply both to the mean and to the extreme values derived from observation. To obtain a correct mean or a probable extreme, we must multiply our facts.\nBibliography.\u2014Gavarret, Jules, Principes G\u00e9n\u00e9raux de Statistique M\u00e9dicale, ou D\u00e9veloppement des R\u00e8gles qui doivent pr\u00e9sider \u00e0 son Emploi. De Morgan, Augustus, An Essay on Probabilities and their Application to Life Contingencies and Insurance Offices. Laplace, Essai Philosophique sur les Probabilit\u00e9s. Poisson, Recherches sur la Probabilit\u00e9 des Jugements. Todd, Tweedy John, Tho Book of Analysis, or a new Method of Experience. Quetelet M.A. Sur l\u2019homme, et le D\u00e9veloppement de\n(William A. Guy.')\nses Facult\u00e9s.\nSTATISTICS, VITAL. See Vital Statistics.\nSTOMACH and INTESTINAL CANAL. See Supplement.\nSUBCLAVIAN ARTERIES (Arterice subclavice, Lat. ; Art\u00e8res sous-clavi\u00e8res, Fr. ; die Schl\u00fcsselbein Pulsadern, Germ.). \u2014 These arteries, two in number, are the great vessels destined to supply the upper extremities with blood. Each passes to the corresponding extremity as a continuous trunk, which in its course gives off numerous collateral branches to the larynx, neck, nervous centres, thorax, &c.\nThe subclavian arteries on the right and left sides respectively differ from each other in their origin, length, direction, and in their relations to surrounding parts, \u2014 differences, however, which occur in the first stage of these vessels only : thus, on the right side, the subclavian artery is derived from the Arteria innominata, and on the left from the arch of the aorta ; but on both sides alike the lower or outer margin of the first rib marks the termination of each vessel, which, in its further course towards the upper extremity, is designated by the name of Axillary.\nThe course of each subclavian artery may, in general terms, be described as representing an arch, the convexity of which looks upwards towards the neck, whilst the concavity has an aspect downwards, and corresponds closely to the apex of the lung. On the right side the extremities of this arch are nearly on the same level, the outer, however, passing a little lower down than the inner; whilst on the left side the reverse obtains, the inner (or cardiac) extremity of the arch of the left subclavian artery, which springs from the aorta, being on a much lower level than the outer. Owing to the difference in the origin of these vessels, the left subclavian artery has a stage wdthin the thorax, which does not belong to the artery of the right side.\nThe subclavian artery on each side is accompanied by a vein of large size ; the direction of the vein is much more transverse than that of the artery, so as to resemble in some respect, as Cruveilhier expresses it, \u201c the cord of the arc which the artery describes:\u201d the subclavian vein is consequently the shorter vessel of the two.\nThe course of each subclavian artery may be divided into three stages, to which the majority of anatomists agree in assigning the following limits : \u2014\nA first stage comprises that portion of the vessel, from its origin, to the inner, or tracheal edge, of the scalenus anticus muscle.\nA second stage includes so much of the artery as is contained between the sca-leni muscles ; and the\nThird stage extends from the acromial edge of the scalenus anticus muscle to the lower or outer margin of the first rib : at this latter point the axillary artery commences.\nAccording to some anatomists (as Bichat), the outer margin of the scaleni muscles is the limit between the subclavian and axillary","page":814},{"file":"p0815.txt","language":"en","ocr_en":"SUBCLAVIAN ARTERIES.\n815\nvessels ; others (as Cruveilhier) insist upon the clavicle as the line of demarcation between these two great trunks ; but the stages above assigned to the subclavian arteries are strictly in accordance with the views of British anatomical authorities.\nThe subclavian vein may be divided into tivo stages, which correspond to the second and third stages of the artery ; at the inner edge of the scalenus anticus muscle on each side of the neck, the subclavian joins the internal jugular vein to form the vena inno-minata (of Meckel), which latter vein consequently corresponds to the first stage of the subclavian artery.\nAs the right and left subclavian arteries differ from each other essentially in their first stage, it is necessary to describe them separately in this portion of their course.\nFirst stage of the right subclavian artery.\n\u2014\tThis portion of the vessel varies from one to two inches in length ; it extends from the summit of the arteria innominata to the tracheal edge of the anterior scalenus muscle, and passes in a direction outwards, and slightly upwards. At its commencement it lies to the right of the trachea, and is concealed by the sterno-clavicular articulation.\nIn this stage the artery is contained in the antero-infenor triangle of the neck. The following structures here constitute its anterior relations, and are described in the order in which they present themselves in dissection :\n\u2014\tThe skin, and subcutaneous cellular stratum, with one sheet of the cervical fascia, being divided, the tendon of the sterno-mas-toid muscle (sternal origin) is exposed : behind it is a cellular interval of constant existence, though of variable extent, where anastomosing veins and small arterial twigs ramify. The outer edges of the sterno-hyoid and of the sterno-thyroid muscles are more deeply placed ; the latter extends much further outwards than the former, and hence it more directly overhangs and conceals the subclavian artery. These muscles are contained in distinct sheaths (furnished by the deep cervical fascia), which isolate them, as well from the superficial as from the deeper-seated parts : the layer of fascia which forms the back of the sheath of the sterno-thyroid muscle is the deepest lamina of the cervical aponeurosis ; towards the middle line it invests the front of the trachea, and the deep thyroid veins; externally,it covers the carotid and subclavian arteries, with their accompanying veins, and is connected to the scalenus anticus muscle, whilst, inferiorly, it is attached to the clavicle, to the sternum, and to the \u201c thoracico-cervical septum,\u201d through the intervention of which it is connected with the fibrous layer of the pericardium. On the removal of this fascia from the region under consideration, the immediate anterior relations of the subclavian artery are exhibited ; they are as follow : \u2014\na. The right vena innominata, its satellite vein, lies anterior to the artery in the first stage of its course, but on a lower plane, and\nseparated from it by the phrenic and vagus nerves, and by the internal mammary artery.\nb.\tThe internal jugular vein, which passes downwards and outwards into the subclavian vein, in order to form with it the right vena innominata, crosses the front of the artery nearly at right angles : an interval (the result of the inclination outwards of the internal jugular vein) occurs between this vein and the common carotid artery ; and here\nc.\tThe vagus nerve passes over the subclavian artery ; whilst internal to this point the subclavian artery is enveloped in a nervous sheath, formed of\nd.\tThe cardiac filaments of the sympathetic nerve.*\ne.\tLastly, the phrenic nerve constitutes an important anterior relation of the subclavian artery, passing anterior to the very last portion of the first stage of the vessel, though not in contact with it. The trajet of the nerve is external to that of the internal jugular vein, which, as before mentioned, crosses the same aspect of the artery. There is no actual contact between the phrenic nerve and the subclavian artery, because the nerve, as it leaves the inner margin of the scalenus anticus muscle, lies on and crosses the origin of the mammary artery, which thus separates the nerve in question from the trunk of the subclavian. The relation of\nf.\tThe vertebral vein, to the subclavian artery, is subject to much variety. According to the descriptions of most anatomists, it passes posterior to the artery ; but the writer has found this vein nearly as often in front of the artery as behind it ; and occasionally he has seen the vertebral vein terminate in two branches, of which one passed on the anterior, and the other on the posterior aspect of the subclavian artery, so as to encircle that vessel before they opened into the vena innominata. When the vertebral vein is single, and passes over the front of the subclavian artery, it usually lies internal and parallel to the internal jugular vein.\nThe anterior relations of the first stage of the right subclavian artery, are, therefore, the following :\u2014\n1.\tIntegument, subcutaneous areolar tissue,\nfascia.\n2.\tSterno-mastoid muscle, sterno-clavi-\ncular articulation.\n3.\tSterno-hyoid and thyroid muscles, iso-\nlated from one another, and from the last-named muscle, by layers of the cervical fascia.\n4.\tThe deep layer ofthe cervical aponeurosis.\n5.\tThe phrenic and vagus nerves, and the\ncardiac filaments of the sympathetic nerve.\n6.\tThe right innominate, and internal jugu-\nlar veins, and sometimes\n7.\tThe vertebral vein.\nThe remaining relations of the artery in its first stage are the following : \u2014\nInferiorly, it corresponds to the lqpp of the\n* Yide art. Neck, vol. iii. note to p. 575.","page":815},{"file":"p0816.txt","language":"en","ocr_en":"SUBCLAVIAN ARTERIES.\n816\nrecurrent nerve, which sometimes has an anterior relation to the artery also, in consequence of its arising from the pneumogastric at an unusual height in the neck.\nSuperiorly, it gives off the vertebral artery opposite a triangular interval, between the scalenus anticus and longus colli muscles.\nPosteriorly, it corresponds from within outwards, to the transverse process of the seventh cervical vertebra, to the inferior cardiac filaments and inferior cervical ganglion, of the sympathetic nerve, to the recurrent nerve, and finally, to the cone of the pleura.\nNearly the cuter half of the posterior surface of this portion of the subclavian artery is thus closely related to this serous sac, being usually that part of the vessel which is external to the origin of the vertebral branch, and covered on its anterior surface by the internal jugular vein.\nFirst stage of the left subclavian artery. \u2014\u2014 The subclavian artery on the left side arises within the thorax, from the termination of the second stage of the arch of the aorta, at the level of the second dorsal vertebra ; it thence assumes a direction nearly vertically upwards, to the inner margin of the scalenus anticus muscle, and lies to the left side of, and anterior to, the two upper dorsal vertebrae, from which it is but a short way distant.\nWhilst in the cavity of the thorax, the left subclavian artery corresponds, posteriorly, to the inferior cervical ganglion, and cord of the sympathetic nerve, to the thoracic duct, and more remotely to the longus colli muscle and spinal column. Anteriorly, it is in relation with the pleura, and more immediately with the left pneumogastric and phrenic nerves (the latter descends parallel to the artery, but the former crosses it very obliquely, from above downwards and inwards), with the vertebral vein, the confluence of the internal jugular and left subclavian veins, and the great venous trunk which they form by their confluence, viz. the left vena innominata. Internal and ])osterior to the artery are placed the oesophagus and the left recurrent nerve ; internal and anterior to it, is the left common carotid artery ; whilst external to the artery, throughout the entire of its thoracic stage, are the left lung and pleura.\nAfter a course within the thorax of about two inches and a half, the left subclavian artery pierces the \u201cthoracico-cervical septum,\u201d inclines outwards and a little forwards, and attains the tracheal edge of the scalenus anticus muscle, when it bends abruptly outwards ; this terminating portion of the first stage of the vessel (which alone belongs to the cervical region) has, anterior to it, the left internal jugular vein, the vagus and phrenic nerves, and the thoracic duct, just before its termination in the great subclavian vein ; in addition to these relations, the left subclavian has the same coverings as the corresponding portion of the subclavian artery on the right side.\nDifferences between the right and the left subclavian arteries, in their first stage.\u2014Length. The first stage of the left subclavian artery is\nmuch longer than that of the right, which it exceeds by about the length of the Arteria innominata. In the old subject, however, the difference is scarcely so great, for at this period of life, the part of the arch of the aorta, from which the left subclavian artery arises, is higher than that portion of it from which the innominata springs.\nPosition.\u2014The left subclavian artery is nearer to the spinal column, the right to the clavicle and sternum ; consequently the depth of the artery from the surface is considerably greater on, the leftside than on the right, a circumstance which adds greatly to the difficulty of the operation for securing the left subclavian artery in a ligature.\nDirection.\u2014On the left side, the artery in its first stage runs almost vertically, but as it approaches the scaleni, it inclines outwards and forwards, in order to pass between these muscles ; this latter part of the vessel is situated in the neck, and is the only portion of its first stage found there. On the right side, the subclavian artery runs nearly horizontally outwards, and is placed throughout the whole of its first stage within the limits of the anteroinferior triangle of the neck ; for although somewhat concealed at its origin by the sternoclavicular articulation, yet it may be removed from under cover of that joint, by extending the neck, and depressing forcibly the shoulder and clavicle.\nRelations.\u2014a. Pleura.\u2014The pleura is an anterior relation of the commencement of the left, but a posterior relation of the termination of the right subclavian artery.\nb.\tVeins.\u20141. The satellite vein of the right subclavian artery, in its first stage (the right vena innominata), is parallel to the artery, though on a plane anterior and inferior to it, whilst the corresponding vein on the left side crosses the left subclavian at right angles.\n2.\tThe internal jugular vein runs parallel to the left, but intersects at right angles the front of the right subclavian artery.\n3.\tThe vertebral vein is usually anterior to the artery of the left, but posterior to the artery of the right side.\nc.\tNerves.\u2014The phrenic, vagi, and sympathetic nerves are necessarily parallel to the left subclavian artery, in the first stage of its course, in consequence of its vertical direction, whilst they run at right angles to the corresponding part of the right, by reason of its transverse course ; in other respects, however, these nerves hold the same relative position to the subclavian arteries at either side, the phrenic and vagus being anterior, and the sympathetic posterior, to the right and left subclavians respectively. Lastly, the recuirent laryngeal nerve passes behind the right subclavian artery, looping round its under surface, whilst the nerve on the left side encircles the arch of the aorta, internal to the origin of the left subclavian artery ; the recurrent is consequently related to the inner side of the left subclavian artery, but at no part of its course does it lie posterior to that vessel.\nd.\tThe thoracic duct and oesophagus are","page":816},{"file":"p0817.txt","language":"en","ocr_en":"SUBCLAVIAN ARTERIES.\t817\nconnected with the artery of the left side, exclusively. The former holds a double relation to that vessel ; in the thorax it passes behind it, in the neck it rises high above it, and then bends downwards in front of it, to open into the confluence of the great veins. The ceso-phagus, as has been mentioned, lies to the right of the artery.\nThe differences which have thus been pointed out, are of material importance with reference to the operations upon these two arteries.\nIn the remainder of their course the subclavian arteries are perfectly symmetrical, and one and the same description will apply to both.\nSubclavian arteries in their second stage. \u2014 In its second stage each subclavian artery lies in a remarkable intermuscular space, bounded by the scaleni muscles. These muscles (scalenus anticus and scalenus posticus) are closely approximated to each other at their attachment to the tubercles of the cervical transverse processes ; but in descending to their insertions they diverge, leaving between them a space truly triangular, of which the base, placed inferiorly, corresponds to the first rib, and to a small portion of the second. In this space the subclavian artery, the brachial plexus of nerves, and the cone of the pleura, are situated. In front, the artery is in contact with the anterior wall of this triangle, constituted by the scalenus anticus muscle ; behind, it is separated from the posterior boundary of the triangle by the summit of the cone of the pleura, which ascends thus high into the interval between the scaleni, interposing itself between the scalenus posticus and the subclavian artery. Towards the summit of this \u201c scalene triangle\u201d the nervous cords which constitute the brachial plexus are placed along the convexity of the artery, superior and external to it.\nA fleshy slip (Scalenus minimus, Soemmering) is often found to pass from the scalenus anticus to the lower, or costal extremity, of the scalenus posticus ; in this course it runs between the roots of the brachial plexus, and consequently subdivides into two the scalene space. The lower compartment contains the subclavian artery, the cone of the pleura, and the inferior portion of the brachial plexus, constituted by the seventh cervical nerve, and the cord resulting from the union of the eighth cervical, with the first dorsal nerve; whilst in the upper compartment (corresponding to the apex of the triangle), the fifth and sixth nerves of the plexus are seen to unite into a single trunk.\nOn the front of the scalenus anticus, and separated by that muscle from the subclavian artery, are found the following parts : \u2014 Most inferiorly the subclavian vein, lying on the tendinous insertion of the muscle, and under cover of the clavicle ; above the vein the transverse branches of the thyroid axis, viz. the supra-scapular, and the transversalis colli arteries, of which the former is the more inferior, whilst the phrenic nerve descends\nVOL. IV.\nobliquely inwards towards the tracheal edge of the muscle, and intersects these two transverse arteries by passing behind them.\nSuperficial to all these important structures is the clavicular origin of the sterno-cleido-mastoid muscle. In size, shape, and direction, this muscle accurately corresponds to the scalenus anticus, which lies deeper than it, and from which it is separated by the parts just now stated, to lie on the front of that muscle.\nThe separation of the subclavian vein from the subclavian artery in their second stage, \u201c constitutes one of the most remarkable features in its (anatomical) history this condition is not, however, constant, for the vein has been found to lie with the artery between the scaleni (Blandin), and, in a few other equally rare instances, the artery has accompanied the vein superficial to both muscles (Manec, Quain). Lastly, the artery has been seen to pass through the anterior scalenus, and hence to lie in part behind and in part in front of that muscle (Quain). It is to be understood that these deviations from the normal arrangement are remarkably infrequent.\nThe anterior relations of the subclavian artery in its second stage, may be arranged in four orders of parts : \u2014\n1.\tSkin, platysma, fascia.\n2.\tSterno-cleido-mastoid muscle (its clavicular origin).\n3.\tSubclavian vein, supra-scapular and transverse cervical arteries, phrenic nerve.\n4.\tScalenus anticus muscle.\nSubclavian artery in its third stage. \u2014 After the subclavian artery emerges from beneath the scalenus anticus muscle, it inclines downwards and outwards, and thus completes the arch which its entire course represents. In this stage its position is marked by precise limits, which are always recognisable, even in the living subject. The artery, with the vein and brachial plexus of nerves, which still accompany it, is here contained in the postero-inferior triangle of the neck (Omo-clavicular space, Velpeau), the several boundaries of which are constituted by the clavicle, and by the sterno-mastoid and omo-hyoid muscles.\nWhilst traversing this region the subclavian artery lies at first on the scalenus posticus, and then passes on the upper surface of the first rib. The subclavian vein lies inferior and internal to the artery, and on a more superficial plane than it, throughout the entire of this portion of its course ; it also passes with the artery over the first rib. Two superficial grooves in the adult bone mark the trajet and relative position of these great vessels ; a tubercle, which gives insertion to the scalenus anticus muscle, separates these grooves from each other (that for the artery is the more posterior of the two) ; it is constantly present, and serves as a guide to point out with precision the situation of the artery, and so assist the operator to distinguish that vessel from the parts which surround it. Such a guide to the artery is peculiarly valuable, because,","page":817},{"file":"p0818.txt","language":"en","ocr_en":"818\tSUBCLAVIAN ARTERIES.\nin operations upon the larger blood-vessels, the touch often fails to discriminate the proper object, the characteristic pulsation of a arge artery being, under such circumstances, often wanting.\nIn the postero-inferior triangle of the neck the artery is covered by the integument, superficial fascia and platysma, descending superficial (supra-clavicular) twigs of the cervical plexus, and by the external jugular vein. The situation of this vein in the supra-clavicular space, is subject to much variety ; it most frequently runs near to the inner boundary of the triangle and parallel to the outer edge of the sterno-mastoid muscle, but frequently descends in the very centre of the space ; in the latter case it much embarrasses the operator in attempting to expose the subclavian artery.\nNext in order, a number of conglobate glands, and a plexus of anastomosing veins, principally from the scapular region, come into view ; these latter usually communicate with the external jugular, or with the subclavian vein. Areolar tissue which presents a laminated arrangement encloses these glands and superficial vessels, and isolates them from the deeper-seated parts.\nThese structures being removed, the subclavian artery appears to lie within a second triangle of smaller dimensions, bounded internally by the scalenus anticus muscle, externally and superiorly by the omo-hyoid muscle, and inferiorly by the first rib; this bone represents the base of the triangle, and over it the artery is seen to pass. At this depth, two collateral arterial branches of considerable size cross the supra-clavicular space, the one, the transversale colli, above, the other, the suprascapular, below the level of this portion of the subclavian artery ; the latter is placed under cover of the clavicle, and in contact with the front of the subclavian vein. As the suprascapular artery pursues its course towards the shoulder, it crosses in front of the subclavian artery and of the brachial plexus of nerves. Here likewise the clavicle and the subclavius muscle constitute additional anterior relations of the subclavian artery, now near its termination.\nThe nervous bundle of the brachial plexus is parallel to the subclavian artery in its third stage, and lies superior and external to the vessel ; in its descent the lower division of the plexus overhangs the artery, and one or two of the branches (anterior thoracic) cross the anterior surface of the artery, and sometimes even encircle it in a nervous loop.\nThe anterior relations of the third stage of the subclavian artery may therefore be thus arranged : \u2014\n1.\tIntegument, superficial cutaneous nerves, platysma, fascia.\n2.\tAreolar tissue in layers, glands, external jugular vein, an intricate plexus of smaller veins.\n3.\tAnterior thoracic branches of the brachial plexus, the subclavian vein, supra-sca-pular artery, clavicle, and subclavius muscle.\nAnomalies in the origin of the subclavian ar-\nteries.\u20141. The right subclavian artery sometimes arises separately from the arch of the aorta, in which case there is no arteria inno-minata ; the branches that arise from the arch of the aorta are then four in number, but considerable variety has been observed in the relation which the right subclavian bears to the other three branches ; thus,\na.\tIt may occupy the usual position of the innominate artery, being the first in order of the branches of the arch of the aorta ; its relations within the thorax will then correspond with those assigned to the vessel whose place it comes to occupy.\nb.\tIt may be the second in numerical order of the branches of the arch, arising after the right carotid artery, behind which it subsequently passes to arrive at its proper position in the neck.\nc.\tIt may arise after the two carotids as the third branch of the arch ; or,\nd.\tIt may be the last branch of the aorta, and occupy the usual situation of the left subclavian artery. Of the varieties already mentioned, this is the most frequently met with, and, according to the statistics of Professor Quain, it occurs once in every 250 examinations.\ne.\tSometimes (but much more rarely) this vessel arises below the arch, from the thoracic aorta, and its position may be so low, that it will furnish some of the upper intercostal arteries.\nThe course of the artery, when it thus arises from the left of the arch, is very remarkable ; it crosses in front of the spinal column, either behind the oesophagus, or between that tube and the trachea, and necessarily passes across the neck behind all the other branches given off from the arch of the aorta. When thus abnormally situated behind the oesophagus, it has been accidentally wounded by a foreign body which had first transfixed that tube. A remarkable example of this occurrence is mentioned by Mr. Kirby, in the 2d vol. of the Dublin Hospital Reports.\nThe irregularity in question, of the right subclavian artery, was regarded by Dr. Bay-ford as the cause of difficult deglutition, in a case which had been accurately observed for many years, and this new disease, as he considered it, he quaintly termed \u201c Dysphagia lusoria.\u201d *\nIn those instances, where the right subclavian artery has been found to deviate thus strangely from its usual course, the inferior laryngeal nerve presented a remarkable change of direction, depending no doubt on the altered course of the artery ; in all the instances which were noted, the nerve was given off from the pneumogastric, higher up than usual, and passed directly to the larynx, so as not to be entitled to the name of \u201crecurrent.\u201d Dr. Hart, who first directed attention to this fact, has thus clearly explained the connection between the unusual position of the artery and\n* Memoirs of the Medical Society of London, vol. ii. 1793.","page":818},{"file":"p0819.txt","language":"en","ocr_en":"SUBCLAVIAN AKTERLES-\tS19\nthe altered direction of the nerve : \u201cIn the earlier periods of the existence of the foetus, the rudiment of the head appears as a small projection from the upper and anterior part of the trunk, the neck not being yet developed. The larynx at this time is placed behind the ascending portion of the arch of the aorta ; while the brain, as it then exists, is situated so low, as to rest on the thymus gland and front of that vessel. Hence it is that the inferior laryngeal nerves pass back to the larynx, separated by the ascending aorta, the left going through its arch, while the right goes below the arteria innominata.\n\u201c As gestation advances, the head becomes more distinct, and the neck begins to be formed after the second month, which, as it lengthens, has the effect of removing the brain upwards to a greater distance, and of drawing out the larynx from the chest, in consequence of which the nerves of the par vagum and their recurrents become elongated, and hence the circuitous route the latter are found to take afterwards, forming loops in which the aorta and right subclavian artery are, as it were, suspended.\u201d#\n2. The left subclavian artery is much less liable to vary in the mode of its origin than the right ; the varieties observed are also fewer in number, a. The origin of the left subclavian artery is sometimes more approximated than usual to the origin of the left carotid, and in a few instances, b. its origin is fused into that of the latter, so that these two vessels arise by a common trunk, which is a left arteria innominata.\nIt has been observed in those instances where the arch of the aorta is reversed, so as to pass from left to right, that the same irregularities affect the transposed branches which then arise from it, as have been stated to occur when the arch holds its more usual position.\nBranches of the subclavian arteries.\u2014In the number and arrangement of the branches of the subclavian artery so much variety occurs, that no general description could, perhaps, be given, which would accurately describe their arrangement in any one instance, and hence, in works on anatomy, much discrepancy exists on this subject; the following description agrees with that of the best authorities in this country, and is strictly in accordance with the accurate statistical details of Professor Quain.\nIn its firststage the subclavian artery usually gives origin to the following branches\u2014the vertebral, internal mammary, and thyroid axis ; the last, after a very short course, divides in a radiating manner into the inferior thyroid, the swpra-scapular (transversalis humeri), and the transverse cervical (transversalis colli) arteries ; besides, in the majority of instances, the left subclavian artery, in its first stage, furnishes (in addition to the branches already\n* Dr. Hart, in Edinb. Med. and Surg. Journal, 1826.\nenumerated) the superior intercostal artery, a branch which, on the right side, more frequently arises under cover of the scalenus anticus muscle. All these branches arise nearer to the sca!eni muscles, and are consequently more immediately covered by the internal jugular vein on the left side of the neck than on the right.\nThe position of these branches of the subclavian artery, especially on the right side, is of much interest in a surgical point of view. \u201c The situation in which the branches arise from any large artery is an important consideration in its history, because of the influence which their presence has on the result of an operation for the cure of aneurism. And, considering the shortness of the trunk, the size of the offsets, and the manner of their arrangement on the parent vessel, it may be confidently stated that there is no artery in which the influence alluded to is more considerable than in the subclavian.\u201d*\nThe following statistics, derived from the author just quoted, are useful to show the average length of the subclavian artery, from its origin to the point where its first branch arises; in other words, the extent of the artery in its first stage, suitable for the application of a ligature.\nIn sixty-five bodies examined, this distance measured \u2014\ni inch and under\t-\t-\t-\tin\t8\nMore than | inch and not exceeding 1 inch -\t-\t-\t-\t\u201e\t33\nMore than 1 inch and not exceeding 1| inch -\t-\t-\t-\t\u201e\t23\nIf inch (the extreme length) - \u201e\t1\nOccasionally, the vertebral, or inferior thyroid artery, has been seen to arise very close to the arteria innominata.\nIn the second stage the subclavian artery most frequently gives off but a single branch, which soon subdivides into the cervicalis profunda and superior intercostal arteries. It is less usual for these two arteries _ to arise separately; thus, in 285 examinations, this occurred in the proportion of but 1 to 20f, whereas the former arrangement existed in 266 out of the entire number.\nIn the majority of instances no branches arise from the subclavian artery external to the scaleni; but the posterior scapular artery (in general the continued trunk of the transversalis colli) frequently arises from the third stage of the subclavian, and so frequently, indeed, that Cruveilhier regards it, not as a variety, but as the normal arrangement. It is computed by Professor Quain that this occurs in the proportion of 1 in 2\u00a3 cases.\nI. Vertebral artery. \u2014 This artery, which is the first and largest, is at the same time one of the most regular of the branches of the subclavian artery, from the upper and posterior\n* Anatomy of the Arteries of the Human Body, with its Applications to Pathology and Operative Surgery (Plates). By Prof. Quain. Part VI.\n3 G 2","page":819},{"file":"p0820.txt","language":"en","ocr_en":"820\tSUBCLAVIAN\naspect of which it usually arises. There is no example on record where this branch arose either between or beneath the scaleni muscles.\nFrom its origin, the vertebral artery assumes a direction upwards, backwards, and slightly outwards to the foramen, in the transverse process of the sixth cervical vertebra ; having passed through this, it is transmitted from vertebra to vertebra by the foramina which their transverse processes present, until finally it traverses the foramen magnum, where its cerebral, or cranial, stage commences.\nRelations. \u2014 From its origin until it enters the transverse process of the sixth cervical vertebra, the vertebral artery is placed in a muscular interspace, between the longus colli and the scalenus anticus muscles, where it is related in front to the trunk of the subclavian artery, to its own vein, and to the inferior thyroid artery ; the last of these, as it passes transversely inwards, is interposed between the vertebral vessels and the sheath of the carotid artery (in the sheath, the internal jugular vein exactly corresponds to the anterior surface of the vertebral artery). By its posterior surface, the vertebral artery is in relation with the inferior cervical ganglion of the sympathetic nerve.\nFrom the sixth to the second cervical ver-tebra inclusive, the vertebral artery is lodged in the bony foramina of the transverse processes ; in the spaces between these, it is enclosed by the pairs of intertransverse muscles, being in close contact with the anterior set, whilst from the posterior it is separated regularly by the spinal nerves in their trajet outwards. In this part of its course the artery is slightly tortuous, a provision, no doubt, to guard it against injury in the free and varied motions of this portion of the spine. For a similar reason its tortuosity increases remarkably in the subsequent stage.\nHaving passed through the transverse process of the axis, the vertebral artery inclines outwards and slightly upwards, to reach the foramen in the transverse process of the atlas, a deviation from the former vertical course of the artery which is rendered necessary by the superior breadth of the first vertebra.\nWhilst engaged in the curved canal (not foramen) of the transverse process of the atlas, the artery bends abruptly backwards and inwards, so that on emerging from this bone it becomes horizontally placed on the upper surface of the posterior arch of the atlas. Between the occipital bone and the atlas the artery describes a curve, of which the concavity, looking forwards and inwards, embraces the occipito-atlantal articulation, whilst the convexity, directed backwards and outwards, is contained in a triangular space, circumscribed in the following manner by the small rotator muscles of the head. The sides of this triangle are constituted by the superior and inferior oblique muscles respectively, the apex is at the transverse process of the atlas, where both these muscles are attached ; whilst the rectus capitis posticus major (placed in-\nARTERIES.\nternally) represents the base. Deeply situated in this triangular space, the vertebral artery is covered by the splenius and complexus muscles, and rests on the posterior arch of the atlas ; the bone presents a groove for the reception of the artery ; but the sub-occipital nerve, which frequently forms its ganglion in this situation, is interposed. The space which has just been described is occupied by yellow, granular-looking fatty matter, and the occipital artery winds along its upper boundary, freely anastomosing with the vertebral.\nThe vertebral artery next passes beneath the lower edge of the posterior occipito-atlantal ligament, then perforates the dura mater, and, taking a direction upwards, forwards, and inwards, enters the cranium through the foramen magnum. The posterior occipito-atlantal ligament, by arching over the groove on the upper surface of the atlas, forms a foramen for the transmission of the artery.\nAs the vertebral artery advances through the foramen magnum, it passes between the first and second tooth-like insertions of the ligamentum dentatum, and then ascends, lying on the anterior surface of the first of these processes, by which it is separated from the spinal accessory nerve, which latter passes upwards on the posterior surface of the ligament ; here the lingual nerve passes outwards to the anterior condyloid foramen, above the level of the artery.\nWithin the crunium, the vertebral arteries, corresponding at first to the lateral aspects of the upper portion of the medulla oblongata, approximate to each other more and more as they ascend, and ultimately unite at an acute angle, opposite the inferior edge of the pons varolii ; in this manner the basilar trunk is formed.\nBasilar artery (Art\u00e8re m\u00e9so-c\u00e9phalique, Chaussier).\u2014This artery, larger than either of the vertebral arteries, is yet much less capacious than the two vessels conjointly w'hich unite to form it ; its length corresponds accurately to the longitudinal measurement of the pons varolii ; it runs along the median depression of the pons, lodged between that body and the upper surface of the basilar process of the occipital bone, and preserved from pressure by the double concavity of the surfaces between which it is interposed.\nAt its commencement the basilar artery separates from each other the sixth nerves of the opposite sides ; the arachnoid membrane and the dura mater, with the transverse sinus of Haller, are interposed between the artery and the bone, whilst the pia mater alone intervenes between it and the pons. At the antero-superior edge of the pons the basilar artery usually terminates in four branches, two for the cerebrum and two for the cerebellum.\nBranches of the vertebral artery. \u2014 1. Branches to the pr\u00e6vertebral muscles, which anastomose with the cervicalis ascendens and superficialis colli arteries.\n2. Numerous small branches, which enter the spinal canal through the intervertebral","page":820},{"file":"p0821.txt","language":"en","ocr_en":"SUBCLAVIAN ARTERIES.\nforamina, and which are conducted by the nerves to the spinal cord, where they join and reinforce the proper spinal arteries.\n3.\tIn the space between the atlas and occi-pital bone, the vertebral artery sends several long branches down the neck, which are concealed by the splenius and complexus muscles. Accompanied by smaller branches of the occipital, these arteries keep up an important anastomosis on the back of the neck with the cervicalis profunda.\n4,\t5. The proper spinal arteries. These are two in number on each side, an anterior and a posterior branch from each vertebral trunk.\nThe posterior spinal arteries arise lower down than the anterior, and pass downwards and backwards to reach the posterior surface of the medulla oblongata ; from this the artery of each side descends parallel to its fellow, to which it is connected by numerous transverse branches. Opposite the second lumbar vertebra, the posterior spinal arteries cease to exist as distinct trunks.\nThe anterior spinal arteries are given off from the vertebral near to its termination ; these arteries in descending approximate to each other, and at last unite opposite the lower edge of the medulla oblongata ; the single trunk thus formed (Anterior median artery of the spinal cord ) descends tortuously in front of the medulla spinalis, and, passing through the very centre of the fibres of the cauda equina, reaches the lowest portion of the vertebral canal, when it anastomoses with branches of the sacral arteries.\nThe anterior and posterior spinal arteries are connected in every region of the spine with branches of arteries which enter the spinal canal through the \u201c foramina of conjunction;\u201d these reinforcing branches, as they may be termed, of the spinal arteries (derived from the cervicalis ascendens and vertebral in the neck, from the intercostal in the back, and from the lumbar and sacral arteries in the lower portion of the spinal column), cause these arteries which they join to preserve a remarkable uniformity of size throughout their entire course. Both the spinal arteries furnish small branches to the dura mater and to the spinal cord.\nBranches of the basilar artery. \u2014 1. The inferior (or posterior) cerebellar artery. \u2014 This artery seldom arises in precisely the same manner at opposite sides of the same subject. It most frequently springs on one side from the vertebral, and on the other from the basilar trunk. Inclining outwards and backwards, in front of the pyramidal body, the vessel in question passes (according as its origin is from the basilar, or from the vertebral artery) before or behind the sixth nerve ; it then runs through the filaments going to form the ninth nerve, and between the pneumogastric and spinal accessory division of the eighth pair ; it is ultimately distributed internally to the inferior vermiform process and sides of the median fissure (a\nbranch or two may be traced into the choroid plexus of the fourth ventricle), and externally to the inferior surface and circumference of the cerebellum, where it communicates with the superior artery of the cerebellum.\n2.\tThe superior (or anterior) cerebellar artery.\u2014This artery arises near the antero-superior edge of the pons varolii ; it passes in a curved direction outwards and backwards, around the line of junction of the pons with the crus cerebri. It is at first parallel to the posterior artery of the cerebrum, but separated from it by the third nerve. The fourth nerve in its trajet forwards is strictly parallel to the artery as it runs backwards on the side of the pons varolii ; the nerve, however, is contained in a canal between the layers of the tentorium, whilst the artery proceeds beneath that partition, and in contact with the upper surface of the cerebellum.\nThe branches of the superior cerebellar artery are numerous ; they are distributed to the upper surface and circumference of the cerebellum, anastomosing with the inferior cerebellar artery, and also to the pons varolii, velum interpositum, superior vermiform process, and valve of Vieussens. One small branch of this artery accompanies and separates the facial and auditory nerves, entering with them into the internal auditory meatus. Lastly, some of its branches pass on the upper surface of the tentorium, and are distributed to the inferior surface of the cerebrum.\n3.\tPosterior artery of the cerebrum. \u2014 The two posterior arteries of the cerebrum are the terminating branches of the basilar trunk ; each artery passes at first forwards, then backwards and outwards, following the course of the great cerebral fissure, and partly encircling the crus cerebri. For a considerable portion of its course the posterior artery of the cerebrum is parallel to the posterior (or inferior) cerebellar artery; the two arteries, however, are separated from one another, at first, by the third nerve (which latter, in its further course, hooks round the posterior artery of the cerebrum), and subsequently by the tentorium. At the point where the posterior artery of the cerebrum changes its direction in order to pass backwards and outwards, it is joined by the \u201c posterior communicating artery,\u201d and by this means a communication is established between the internal carotid and basilar arteries.\nThe posterior artery of the cerebrum is chiefly distributed by long slender branches to the inferior surface of the posterior lobe of the cerebrum, but it furnishes, in addition, the following collateral branches: 1. Numerous small twigs which enter the floor of the third ventricle, through the apertures in the locus perforatus m\u00e9dius, or are distributed to the crura cerebri, corpora albicantia, and tuber cenereum ; and 2. a choroid branch, which winds round the crus cerebri, enters the cerebral fissure, and is lost, in the velum interpositum, corpora quadrigemina, and choroid plexuses.","page":821},{"file":"p0822.txt","language":"en","ocr_en":"822\tSUBCLAVIAN ARTERIES.\nVarieties occasionally observable in the vertebral arteries. \u2014 ]. Of origin.\u2014a. It has already been mentioned that the vertebral artery may arise from different portions of the first stage of the subclavian artery being sometimes nearer, and sometimes further removed, from the innominata; but, independently of these varieties, the vertebral artery on the right side is\nb.\tSometimes furnished by the common carotid artery. In all the cases where this anomaly has been observed, the right subclavian artery was given off directly as a branch of the aorta. Again,\nc.\tThe vertebral artery sometimes comes off from the arch of the aorta. This irregularity is as unfrequent on the right, as it is common on the left side. When the left vertebral artery springs from the arch of the aorta, it usually arises between the left carotid and the left subclavian arteries, though sometimes its origin has been found to the left of all the other branches of the arch.\nd.\tIn a few instances, more than one vessel has been found to constitute the origin of the vertebral artery; thus, it may be formed by the union of two roots, both arising from the subclavian artery, or one from the subclavian and the other from the aorta. In one example, where it was formed by three roots, two of these were derived from the subclavian, and the third from the inferior thyroid artery. These roots of the vertebral artery in some instances united before the artery had become engaged in the vertebral foramina, whilst in others the union took place subsequently.\n2.\tOf size.\u2014There is often a considerable difference in the size of the two vertebral arteries, which is stated to be most frequently in favour of that of the left side ; thus, in 98 observations made by Mr. Davy, the left vertebral artery was the larger in twenty-six, and the right in eight instances only.\n3.\tOf course and relations.\u2014The vertebral artery may enter the transverse process of the last cervical vertebra (though the contrary has been asserted), or it may enter one of the foramina higher than that in the transverse process of the sixth, which latter it usually selects. When the artery enters any vertebra higher than the sixth cervical, it always occupies an unusually superficial position in the neck, lying external and parallel to the common carotid artery, for which, consequently, it is liable to be mistaken. ( Vide Carotid Artery.)\nThe vertebral vein corresponds to the cervical stage only of the artery. Its origin is found in some branches from the deep muscles at the back of the neck, joined by one from the occipital vein, and by another which passes through the posterior condyloid foramen. The vertebral vein traverses the canal in the transverse process of the atlas, and descends through the same foramina by which the artery ascends ; whilst here it lies in front of the artery, and has the same relations as that vessel. Emerging from the foramen in\nthe sixth vertebra, the vertebral vein (liable to the varieties already specified) opens into the vena innominata close to its junction with the internal jugular.\nII. Internal mammary artery.\u2014This artery arises (more externally than the vertebral) from the anterior surface of the subclavian, and near to the inner margin of the anterior scalenus muscle. From this origin it runs, first forwards, then downwards and inwards, and enters the thorax, lying between the pleura and the internal layer of intercostal muscles.\nPrevious to entering the thorax, the internal mammary artery is crossed anteriorly by the vena innominata and by the phrenic nerve : the latter intersects the artery obliquely from above and without, downwards and inwards. In the thorax, however, the nerve attains a position much posterior to the artery.\nThe mammary artery descends on the back of the anterior parieties of the chest a little external to the junction of the costal cartilages with the sternum, and is covered posteriorly by the pleura at the line of reflexion of that membrane to form the side of the anterior mediastinum. Arrived at the cartilage of the third rib, the artery in its farther descent inclines a little outwards, and becomes separated from the pleura by the fibres of the triangularis sterni; the vessel is now placed between that muscle, which lies behind it, and the internal layer of intercostal muscles and the cartilages of the lower true ribs, which constitute its anterior relations. Opposite the cartilage of the seventh rib the mammary artery terminates by dividing into two branches, an external and an internal.\nBranches of the mammary artery. \u2014 I. Mediastinal branches, which are distributed to the thymus gland (thymic arteries), and the cellular issue of the anterior mediastinum.\n2.\tA descending muscular branch to the diaphragm (superior phrenic), also termed, from its so constantly accompanying the phrenic nerve, the comes nervi phrenici. This branch accompanies the nerve in a tortuous manner, between the pleura and the pericardium, to reach the upper surface of the diaphragm, where it anastomoses with the phrenic arteries from the aorta.\n3.\tThe anterior intercostal arteries.\u2014These are distributed to the six upper intercostal spaces ; but their number is greater than that of the spaces for which they are destined, as two branches are frequently found between adjacent ribs, and this arrangement may even prevail in all of these intercostal spaces.\nThe anterior intercostal arteries pass outwards in the intervals between the two planes of intercostals, in which muscles some of their branches terminate ; others are lost in anastomosing with the intercostal arteries from the aorta, whilst many perforate the muscular fibres, and, arriving on the external surface of the thorax, dip into the pectoral muscles","page":822},{"file":"p0823.txt","language":"en","ocr_en":"823\nSUBCLAVIAN ARTERIES.\nand the mammary gland. In both these latter situations the arteries in question communicate freety with the external thoracic branches of the axillary, thus forming an important connection between the circulation of the interior and that of the exterior of the thorax.\nThe terminal branches of the internal mammary artery are two in number, viz. internal terminal branch (Ramus abdominalis) and an external (Arteria musculo-phrenica, Haller).\n4.\tThe internal, or the abdominal branch, is the smaller of the two, yet in direction it represents the parent trunk. Having communicated with the artery of the opposite side behind the xiphoid cartilage, it escapes from the thorax through a small triangular interval between the fibres of the diaphragm, and then immediately enters the sheath of the rectus abdominis, descending between the muscle and the posterior lamina of the sheath. Having arrived opposite the umbilicus, it becomes distinctly continuous with ascending branches of the internal epigastric artery ; it likewise furnishes many branches to the substance of the rectus muscle, and others which, piercing the sheath, are widely distributed to the broad muscles of the abdomen.\n5.\tThe external terminating branch (or the arteria musculo-phrenica), is larger than the internal, from which it separates nearly at right angles, passing almost transversely outwards in a curved course along the superior line of attachment of the diaphragm to the false ribs. In this course the artery gives off, a. numerous phrenic branches of large size, which enters the diaphragm all along its costal attachment ; and b. anterior intercostal branches, which supply the lower intercostal spaces in precisely the same manner as those from the mammary trunk supply the upper, and which have been already described.\nVarieties. \u2014 The mammary artery presents but few varieties either of origin or position ; in 290 out of 297 examinations, this artery occupied its normal position. In one instance it arose beneath, in six instances external to the scalenus muscle, and in one only of the six was it derived from the axillary artery (Quain).\nMuch more rarely still does the mammary artery deviate in the opposite direction, i.e. inwards ; it has, however, been seen to spring from the arch of the aorta, and also from the arteria innominata. Occasionally too it arises in common with the thyroid axis.\nTwo veins (one on either side of it) accompany each internal mammary artery ; they are formed by branches corresponding to those given off by the artery, with the exception (according to Cruveilhier) of the vein accompanying the arteria comes nervi phrenici, which on both sides terminates separately. On the right side the mammary veins open into the commencement of the vena cava; on the left side, they are connected with the corresponding vena innominata. \u201c The mammary arteries are remarkable for the number of their inosculations, and for the distant parts of the arterial system which they serve to\nconnect : they anastomose with each other, and their inosculations with the thoracic aorta encircle the thorax. On the parieties of this cavity their branches connect the axillary and subclavian arteries ; on the diaphragm they form a link in the chain of inosculations between the subclavian artery and abdominal aorta ; and in the parieties of the abdomen they form an anastomosis most remarkable for the distance between those vessels which it serves to connect, namely, the arteries of the superior and inferior extremities.\u201d*\nIII. Thyroid axis. \u2014 This artery springs from the anterior aspect of the subclavian trunk, close to the inner edge of the scalenus anticus muscle, and consequently from the very last portion of the artery in its first stage.\nThe thyroid axis forms a trunk only a few lines in length, which projects forwards and a little upwards : the phrenic nerve is applied against the outer surface of this artery, and still retains the same relation to it, even where the artery arises more externally than usual, as if in such cases the nerve were drawn outwards by the artery. This arrangement was observed where the thyroid axis arose from the third stage of the subclavian. The thyroid axis usually terminates in three branches :\u2014\n1. Inferior thyroid artery.\u2014From the thyroid axis, this branch passes a little upwards, and then turns inwards and backwards, describing a curve, of which the concavity looks forwards and downwards, corresponding to the carotid sheath. The artery next descends, but soon afterwards inclines upwards and inwards until it reaches the thyroid body, thus forming a second curve the reverse of the former one, for the concavity of this second curve looks upwards and backwards, and is crossed anteriorly by the recurrent nerve.\nThe anterior relations of this artery are the following :\u2014\nIt is crossed in its first curve, opposite the sixth cervical vertebra, by the sympathetic nerve, which more frequently on the right than on the left side however, joins the middle cervical ganglion in this situation. The internal jugular vein, vagus nerve, and carotid artery, contained in their common sheath, are the next parts which cross the artery ; and lastly, the recurrent nerve, sub-hyoid muscles, and thyroid gland, lie in front of it.\nThe recurrent nerve lies in front of the second curve of the artery.\nThe inferior thyroid artery is posteriorly in relation with the vertebral artery, the longus colli muscle, and the vertebral column ; and, on the left side, with the oesophagus and thoracic duct.\nThe thoracic duct very frequently passes up behind the inferior thyroid artery to the level of the sixth cervical vertebra, where, bending downwards and forwards, it arches over that vessel and descends in front of it, to terminate in the subclavian vein.\n* Harrison\u2019s Surgical Anatomy of the Arteries. 4th Edition, p. 141. Dublin.\n3 g 4","page":823},{"file":"p0824.txt","language":"en","ocr_en":"824\tSUBCLAVIAN ARTERIES.\nBranches of the inferior thyroid artery. \u2014\na.\tArteria cervicalis ascendens. \u2014 This branch (arising from the upper convexity of the thyroid, where that vessel changes its direction to pass downwards and inwards beneath the carotid sheath) passes upwards on the superficial surface of the scalenus anticus, parallel and internal to the phrenic nerve. The cervicalis ascendens (frequently as large as the thyroid itself) furnishes numerous muscular branches to the levator anguli scapulae, longus colli, rectus capitis anticus major, and to the scaleni muscles, some of which anastomose with branches of the occipital artery ; it likewise gives off spinal branches, which enter the spinal canal along the cervical nerves, and are distributed to the cord, anastomosing both within and without the canal of the vertebra with the vertebral artery.\nBy some anatomists the cervicalis ascendens is regarded as a branch of the thyroid axis, from which it not unfrequently arises ; in some rare instances it has originated directly from the subclavian artery. Sometimes it is of very large size, and takes the place of the occipital artery or of the cervicalis profunda.\nb.\tThe inferior thyroid artery furnishes several descending branches, which from their destination may be termed oesophageal, tracheal, and bronchial.\nc.\t' Terminal or thyroid branches. \u2014 The inferior thyroid artery becomes extremely tortuous as it approaches the thyroid gland ; at last it divides into two or three large branches, which enter the gland by its deep surface, and which, in the substance and around the margin of the gland, communicate freely with the corresponding artery from the opposite side, and with the superior thyroids of the external carotid.\nThe reader is now referred to the article Scapular Region, in which the remaining branches of the thyroid axis, viz. the suprascapular and transverse cervical arteries, have already been followed to their ultimate distribution ; it will be only necessary in this place to describe the cervical portions of these two collateral branches.\n2.\tSupra-scapular artery {Arteria transversale humeri). \u2014 This artery is at first directed downwards, but having reached the shelter of the clavicle, it passes nearly horizontally outwards to the superior costa of the scapula. It crosses over the phrenic nerve, the scalenus anticus muscle, and the subclavian vein ; it then runs outwards in contact with the vein, and bound to it by cellular tissue ; it next passes across the subclavian artery and brachial plexus of nerves, and finally arrives at the supra-spinal fossa, which it enters by passing over the superior ligament of the scapula.\nThe supra-scapular artery has, anterior to it, the sterno-mastoid muscle, theclavicle,and the omo-hyoid and trapezius muscles. It accurately corresponds to the base of the supraclavicular space.\n3.\tArteria Transversale Colli. \u2014 This artery is larger than the preceding ; from its origin\nit passes transversely outwards over the scalenus anticus muscle and the phrenic nerve ; at the outer edge of this muscle, it inclines backwards and runs through the midst of the branches of the brachial plexus. The artery at this stage crosses the summit of the omo-clavicular triangle, above the level of the subclavian artery. In the space between the stemo-mastoid and the trapezius, the transverse cervical artery gives off a large branch, the cervicalis superficialis, which is destined for superficial structures, integuments, pla-tysma, glands, and superficial layer of muscles.\nThe cervicalis superficialis ascends in the posterior superior triangle of the neck, through a chain of conglobate glands, and through the meshes of the cervical plexus of nerves, anastomosing with branches of the occipital and vertebral arteries, and passing finally under cover of the trapezius, to which it distributes numerous twigs, as also to the levator anguli scapulae and splenius.\nAfter this the continued trunk of the transverse cervical artery is usually called postenor scapular artery, which has elsewhere been described.\nThe postenor scapular, and the cervicalis superficiale arteries, very frequently arise separately, instead of springing by a common trunk from the thyroid axis; in such cases the posterior scapular is usually given off by the subclavian artery external to the scaleni.\nIV.\tArteria Cervicale profunda. \\ These ar-\nV.\tSuperior Intercostal Artery. J teries (as has been already mentioned) generally arise by a short trunk common to both, from the subclavian in its second stage. An analogy may thus be observed between this trunk and the aortic intercostal arteries; for, like them, it divides into an anterior or intercostal branch (the superior intercostal artery), and a posterior or muscular branch (the cervicalis profunda). The cervicalis profunda passes from its origin backwards and upwards, between the transverse process of the last cervical vertebra and the first rib. When a supernumerary cervical rib exists, the artery then passes between this latter and the first dorsal rib. It thus gains the posterior aspect of the neck, and ascends between the spinous and transverse processes of thevertebr\u00e6, separated from the lamin\u00e6 by the deep layer of muscles, and covered by the great complexus muscle.\nIn this course the cervicalis profunda anastomoses with the large muscular branches which descend from the occipital and vertebral arteries.\nThe deep cervical artery sometimes passes backwards at a higher or lower level than that above specified ; these deviations must be rare, since none of them existed in 40 subjects examined specially with reference to this subject by Cruveilhier. In the extensive tables collected by Professor Quain, and which have already been frequently alluded to in this article, seventeen instances are given where this artery passed between the first and second rib ; in a very few examples, it escaped from","page":824},{"file":"p0825.txt","language":"en","ocr_en":"SUBCLAVIAN ARTERIES.\t825\nthe thorax through the second intercostal space, and in some other equally rare cases, it has been seen to penetrate between the sixth and seventh cervical transverse processes.\nThe superior intercostal artery passes downwards in a tortuous manner into the thorax, and gives offbranches which run outwards and supply the two or three upper intercostal spaces ; the artery of the right, usually passes to one intercostal space lower than that of the left side. The branch to the first intercostal space is in general the smallest.\nThe trunk of the superior intercostal artery, as it descends,has the following relations:\u2014in front, it is covered by the pleura and lung; internal to it are placed the first dorsal ganglion of the sympathetic nerve, and the longus colli muscle ; whilst posteriorly, it corresponds to the first dorsal spinal nerve (in its ascent to join the last cervical), and to the neck of the first rib.\nIn addition to the branches furnished to the intercostal spaces, and which are two or three in number, the superior intercostal gives off several small branches which enter the spinal canal through its lateral foramina, and also a branch which passes downwards and establishes a communication with the first aortic intercostal artery.\nIt has been already stated that the superior intercostal and the deep cervical arteries most frequently arise by a common trunk ; when they arise separately, the left superior intercostal artery is generally derived from the first stage of the corresponding subclavian artery.\nOperative proceedings.\u2014It is not intended in this place to enter into all the details connected with the surgical relations of the subclavian artery, since in the article which treats of the surgical anatomy of the neck will be found clearly described the modes of procedure to be adopted by the surgeon in the operations for the ligature of this artery in different parts of its course; the following few observations, which may be regarded as supplemental to those just alluded to, naturally follow the description which has been given of the subclavian artery in the preceding pages.\nFirst stage. \u2014 When the relations of the subclavian artery on the right side, internal to the scaleni muscles, are carefully reviewed, the inner half of this stage of the vessel will appear to be the most eligible for the application of the ligature, and the object of the operator should be to secure the artery on the cardiac side of its vertebral branch, as in that situation the pleura is comparatively little exposed to injury ; the jugular vein should lie to the outside, and the vagus nerve to the inside of the ligature, and any undue disturbance of these parts, especially of the latter, ought to be most sedulously avoided.\nThe artery was tied, for the first time in this situation, by Mr. Colles, in the year 1813. In that instance, as in every subsequent one\nwhere the operation has been repeated, the result has proved unfavourable ; nevertheles s, success has been so nearly attained in some of these cases, that few will be found to agree with Blandin in pronouncing this operation \u201c tout a fait irrationnelle ; \u201d nor are we to view with favour the alternative first suggested by Mr. Shaw, and lately revived and recommended to the profession in some recent works on surgery, viz., to remove the arm at the shoulder-joint, and to make pressure on the aneurismal tumour.\nIn the majority of the cases in which hitherto the subclavian artery has been tied internal to the scaleni, the cause of death was referable to secondant haemorrhage ; the unavoidable proximity of the ligature on the one hand to the heart, on the other to the aneurismal sac, and the small extent of this part of the subclavian artery to which a ligature can be applied, without interfering with the collateral branches, are probably the chief circumstances which determine this fatal accident. If, in the desire to avoid the vertebral, thyroid, and mammary branches, the ligature be applied too close to the mouth of the carotid artery, the current of blood through the latter vessel will then, with almost positive certainty, disturb those sanative processes at the seat of ligature, on which the ultimate success of the operation depends ; and hence, doubtless, has originated the proposal to secure at the same time both branches of the innominata. The incisions necessary to expose the one, would amply suffice for the ligature of the other ; the circulation through the head and upper extremity might afterwards be carried on without material injury, and the formation of a coagulum, more lengthy than that afforded by the operations hitherto performed, might lead to a favourable result. This suggestion is due to Dr. Hayden, and is mentioned in his account of the case in which he tied this artery in its first stage, so far back as the year 1835.\nThe following brief particulars of a case which lately came under the writer\u2019s notice, may be adduced as furnishing an additional argument in favour of this proposal. A woman, about 25 years of age, became the subject of an aneurism, situated at the root of the neck, which was regarded as originating from the arteria innominata. The subclavian and carotid arteries were tied at one and the same time, on the principle of Brasdor :\u2014\u201c On the fourteenth day after the operation, the ligature came away from the subclavian artery without any haemorrhage, and every thing promised a favourable result, especially as the pulsation in the tumour had quite disappeared. On the sixteenth day, the patient, a woman of violent temper, had a quarrel with the nurse, when she jumped out of bed, seized a pillow and some books, and threw them at her: while making this exertion, haemorrhage set in from the carotid.\u201d A renewal of the haemorrhage proved fatal. On examination it appeared that \u201c petfeet union had taken place where the ligature had been applied to the sub-","page":825},{"file":"p0826.txt","language":"en","ocr_en":"826\tSUBCLAVIAN ARTERIES.\nclavian artery, but a small opening was found in the carotid from which the haemorrhage had proceeded.\u201d\nIn this instance the innominata was healthy ; but, a little to the left of the origin of that vessel, the aneurismal tumour, which was of a pyriform shape, sprung from the arch of the aorta, and thence passed upwards into the neck, in front of, and overlapping the arteria innominata. It is an extremely interesting circumstance connected with this case, \u201c that the tumour was filled with a firm coagulum.\u201d\nThis is the only instance, as far as the writer knows, in which a ligature placed on the subclavian artery, in its first stage, became detached ivithout the supervention of secondary haemorrhage. In none of the cases where this artery alone was secured did this circumstance occur, much less in any of these instances did \u201cperfect union,\u201d the result of adhesive inflammation, follow the application of the ligature.*\nUntil very recently it was thought that the ligature of the subclavian artery internal to the scaleni was feasible on the right side only, and this opinion of British surgeons originated perhaps in Mr. Colles\u2019 statement, that \u201c this operation, difficult on the right, must be deemed impracticable on the left subclavian artery.\u201d Dr. Rodgers, of New York, has, however, lately succeeded in securing the left subclavian artery in its first stage. The result of this case does not verify the opinion of Velpeau, that \u201cthe operation would be much less dangerous on the left side than on the right,\u201d as the patient died of secondary haemorrhage on the fifteenth day.\nBritish anatomists will be little disposed to agree with Velpeau in such a prediction, and still less will they concur with him in thinking that it would be easier to tie the left subclavian artery than the right ; on the contrary, the great depth of the left subclavian trunk from the surface, the short distance to which it rises out of the thorax, and the close connection of the veins and nerves with its anterior surface, must entitle this operation to the distinction of being one of the most difficult, whilst the peculiar and unseen risk of wounding the thoracic duct must ever render it one of the most dangerous, in surgery.\nSecond stage. \u2014 The subclavian artery has been tied between the scaleni muscles in a few instances. This operation was first performed by Dupuytren, in 1819, in a case of traumatic axillary aneurism ; the result was successful; yet there is nothing in this operation to recommend it, provided there be the option of tying the artery in the supra-clavi-cular space. Dupuytren did not (as some have supposed) intend it to supersede the latter operation ; he advised it in those cases only, where the depth of the vessel in its\n* The full details of this interesting case, which occurred in the practice of Dr. Hobart, of Cork, will be found in the forthcoming edition of \u201c Flood\u2019s Surgical Anatomy of the Arteries,\u201d edited by Dr. Power, one of the lecturers at the Richmond Hospital School, to whom the writer is indebted for the facts already quoted.\nthird stage is unusually great, in consequence of some peculiarity of development, or the unnatural elevation of the clavicle produced by an aneurismal tumour.\nThe anatomical objections to this innovation, which is sanctioned by the authority of Dupuytren, are the following, and they are sufficiently important to justify the conclusion that, where a choice exists, the third stage of the artery should always be selected for the application of a ligature.\n1st That in order to expose the subclavian artery in its second stage, the division of two muscles is required, viz., the clavicular portion of the sterno-mastoid, and the scalenus anticus.\n2d. That considerable risk of injuring the phrenic nerve is incurred.\n3d. That the ligature must be in close proximity to the branches usually furnished by the subclavian artery between the scaleni, viz., the cervicalis profunda, and superior intercostal; and,\n4th. That from its close connection with the artery, the cone of the pleura is endangered.\nThese theoretical objections to the ligature of the subclavian between the scaleni, are not the less deserving of notice because they were originally passed over in silence, and they go far to disprove the \u201c innocuit\u00e9\u201d of the operation, an advantage which has been claimed for it by Dupuytren.*\nThe objections which have just been enumerated, are not however of sufficient weight to forbid a repetition of the operation in any case where insuperable difficulties are encountered in attempting to tie the artery in its third stage ; under such circumstances, the surgeon would evince both skill and dexterity by dividing, as far as necessary, the scalenus anticus muscle, and thus accomplishing the object of the operation ; and in so doing he would follow the example of the late Mr. Liston, who, in a parallel case, thus succeeded in securing the artery between the scaleni.\nWhere the outer edge of the muscle alone is divided, and where proper caution is used, the safety of the phrenic nerve is not necessarily compromised ; but without very great caution in passing the needle, the pleura will suffer injury, as it is placed in close contact with the back of the artery. It should also be borne in mind, that the phrenic nerve has in a few instances been seen to pass down beneath the clavicle, lying on the outer edge of the scalenus anticus muscle ; should such an anomaly occur in a person subjected to Du-puytren\u2019s operation, the nerve could scarcely escape from injury. This irregularity in the cervical stage of the phrenic nerve, has usually been seen in connection with a variety of origin of the axis thyroideus, which has been already adverted to.-f\n* Yide \u201c Le\u00e7ons Oracles,\u201d tom. iv. ; and M. Marx account of the operation in the \u201c Repertoire G\u00e9n\u00e9rale d\u2019Anatomie,\u201d No. 2.\nf It may he presumed that the phrenic nerve was thus unusually placed in a case which occurred in the practice of Mr. Bransby Cooper, and which he","page":826},{"file":"p0827.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\nIn its third stage, the subclavian artery has very frequently been the subject of operation, and the ligature of the vessel in this situation, in a large number of the cases recorded, has been eminently successful. Mr. Ramsden, of St. Bartholomew\u2019s Hospital, in the year 1809, was the first who secured the artery in its third stage, and since then the operation has been successfully repeated by many surgeons, in this as well as in other countries.\nAlthough the subclavian artery, above the clavicle, is covered by no muscular fibres except those of the platysma, yet it always lies at a considerable depth, which varies much in different persons ; the statement of Dupuytren will generally be found correct, viz., \u201c that the third part of the course of the subclavian artery is placed more superficially in those who have long, slender necks, with lean and pendant shoulders, but is, on the contrary, deeply hidden in persons who have short, thick necks, and muscular shoulders.\u201d*\nIt is an unfortunate circumstance that the disease for which the operation is usually undertaken, should so constantly be the cause of great difficulty in its performance, for an axillary aneurism of any considerable size cannot fail to elevate the clavicle considerably. This fact is well illustrated in the embarrassments experienced in a case where the subclavian artery was tied by the late Professor Todd, one of the surgeons of the Richmond Hospital, and which are recorded in the third volume of the Dublin Hospital Reports. So great have been the difficulties experienced in the operation, that on one occasion Sir A. Cooper was obliged to abandon the attempt, and on another (already alluded to) Mr. Liston was compelled to tie the artery between the scaleni, finding it impracticable to expose the vessel in its third stage.\n(B. Geo. MlDowel.)\nSUPRA-RENAL CAPSULES. {Die Nebenniere, Germ. Capsules suprar\u00e9nales seu atrabilanes, Lat. Capsules suprarenales, atrabilaires, Fr.) \u2014 In the bodies of Vertebrata we find a series of organs, which possess a great outward resemblance to the glands, but distinguish themselves from these by the constant absence of a duct. To this class belong the spleen, the thymus, the thyroid,\nthus narrates in his published lectures: \u201cSome years ago I performed this operation (ligature of the subclavian artery in the supra-clavicular space) on a clergyman, in the presence of the late Dr. Babing-ton and Mr. Travers ; no difficulty whatever occurred, but immediately after its completion the patient was seized with a constant hacking cough, as if resulting from convulsive motion of the diaphragm. This scarcely ceased night or day until the sixth day after the operation, when he died. 3STo post-mortem examination was permitted; but there can be no doubt, in my mind, that the phrenic nerve had been injured, although it could not possibly have been included in the ligature.\u201d\u2014Vide Med. Gazette. Lond. Vol. xlii. p. 94. July, 1848.\n* Le\u00e7ons Orales, tom. iv. p. 528.\n827\nand the supra-renal capsules. On account of their great richness in blood-vessels, these organs have been named \u201c blood-glands,\u201d or \u00ab glands of blood-vessels,\u201d or \u201c vascular ganglia.\u201d At present we are tolerably acquainted with the range of their distribution, and the differences of their form in the animal kingdom ; we have, also, some knowledge of their minute structure ; but, on the other hand, their physiological import remains just as obscure to the inquirers of the present cpntury as it was to the physicians of ages long gone by.\nThe supra-renal capsules, glandul\u0153 suprarenales seu renes succenturiati, seu capsules atrabilaries, form, in the higher Vertebrata, a double organ, which is constantly placed in the neighbourhood of the kidneys; and from this situation they have received their name. So, also, in the lower Vertebrata they ofien occupy the same situation ; but, not unfre-quently, they are broken up into a number of small glandular bodies. In the Invertebrata they are altogether absent.\nWe shall successively consider, 1. The larger series constituted by the differences of form of supra-renal capsules in the animal kingdom. 2. Their structure. 3. Their development. 4. Their physiological relations.\nI. As already mentioned, supra-renal capsules occur only in the Vertebrata. But we cannot attribute them to all of these without exception. In the lowest Amphibia and Fishes, these organs have not yet been indubitably recognised. Among the Mammalia, the suprarenal capsules exhibit everywhere essentially the same structure, in spite of many differences of form, size, and situation.\nIn Man they possess a half-moon shaped, or triangular and flattened form, with an an-tero-posterior slightly arched surface, and a sharp convex margin. At their bases they are deeply excavated, so that by this part they rest on the upper end of the kidney like a cap. The anterior part of the basis of the supra-renal capsule extends for a considerable distance further forwards on the kidney than the hinder part. The whole organ is included in a covering which consists of closely woven areolar tissue ; and inferiorly, it is attached by a looser areolar tissue to the kidney. At the base of the organ is also found a well-marked fissure, from out of which passes the supra-renal vein, according to Krause\u2019s statement.* The anterior and posterior surfaces of the supra-renal capsules exhibit an irregularly wrinkled appearance, caused by the numerous furrows of the areolar tissue. The size of the supra-renal capsules amounts in the adult to 1\u2014inches (German) in height, and somewhat less in breadth. The greatest antero-posterior thickness occurs in its lowest part, and amounts from 2A\u20144 lines. In their middle the supra-renal capsules are considerably thinner, amounting only to 1|\u20142\\ lines. Their absolute weight is estimated by Meckel\n* Vide Krause\u2019s Handbuch der Anatomie, 2. Auflage, Hannover, 1844. Band 1. S, 668,","page":827},{"file":"p0828.txt","language":"en","ocr_en":"828\tSUPRA-RENAL CAPSULES.\nto be one drachm : according to Krause * it is from 80\u2014120 grains; according to Huschkef from 80\u2014180 grains. The anatomist last named found that its specific weight in the newly-born infant was 1*0333 ; but Krause states the supra-renal capsules of the adult to be of the somewhat lower specific gravity of 1*0163.\nThe two supra-renal capsules of the same individual are generally of different size. Usually the right is of somewhat lesser height, but greater breadth, than the left, which has the contrary diameter the larger.\nThe so-called accessory supra-renal capsules are often found in man. They are small round corpuscles, which, in various numbers, are attached loosely to the inner border of the supra-renal gland, or are sometimes imbedded in an excavation on its surface.\nThe supra-renal capsules of the Mammalia essentially correspond with this description.]; They are always situated on the upper part of the kidneys ; sometimes towards the inner part, sometimes on the upper part of their border, as in man. Sometimes they are not so closely attached to the urinary organs as in man, but are somewhat more removed from them, Thus, for instance, are arranged the supra-renal capsules of the Elephant and Seal. But, in opposition to this constancy of situation of these organs, we find very considerable differences in respect of their size and form.\nThe supra-renal capsules of Monkeys closely approach the shape seen in the human subject ; but, not unfrequently, their size seems somewhat more considerable. Among the Carnivora they are, in the Dog, of an elongated cylindrical form, sometimes thicker at the margin than in the middle, and of a dense solid texture. So also in the Cat, in whom they are roundish, and somewhat flattened. Amongst Insectivora they have in the Mole (Talpa europ\u00e6a) the form of a three-sided pyramid. In the Seal they appear very small, and Cuvier found that their size was, to that of the kidneys, as 1 \u2014160. In this latter animal the whole surface of the supra-renal capsules is divided into a multitude of lobules, or acini. Amongst all the Mammalia, these blood-glands are largest in the Rodentia, their ratio to the kidneys being as 1 to 4 and 5 : this is the case, to wit, in C\u0153logenys Paca, and in the Guinea-pig (Cavia cobaia). They are roundish, and somewhat flattened, in the Rabbit and the Dipus. The supra-renal capsules of the Mouse, the Rat, and the Myoxus Glis, have a shorter form ; while, on the other hand, in Hystrix they become more cylindrical.\n* Loc. cit.\nj* Huschke, Lehre von der Eingeweiden und Sinnesorganen des menschlichen K\u00f6rpers. Leipzig, 1844, S. 357.\nJ Concerning the differences of form of the suprarenal capsides may be consulted the well-known text-books on comparative anatomy of Cuvier and Meckel ; and, especially, Nagel in Muller\u2019s Archiv for 1836, S. 365., and Ecker, Die feinere Bau der Nebennieren, Braunschweig, 1846.\nAmongst the Pachydermata they have, in the Elephant, the form of an elongated cone, and their base is divided into two lobes, and turned backwards. In the Pig, their form is about midway between the cylindrical and the prismatic. Besides this, the supra-renal capsules of this animal possess a considerable size. In the Horse they are flattened and triangular, approaching the human form. Among the Ruminantia they are, in the Rein-deer, of an oval form, which approximates to the spherical. They are elongated in the Sheep. In the Ox, their shape in some degree resembles that of the kidney. Here they are almost crescentic, not unlike a horse-shoe, and their upper extremity is three-sided. Finally, the supra-renal capsules of Cetaceans are, like those of the Seal, exceedingly small, and broken up into a number of small lobes.\nWe find a similar correspondence in the class of Birds. Their supra-renal capsules are generally small in proportion to the size of the body j sometimes spherical, sometimes oval ; and, in general, divided into lobules. They lie at the inner extremity of the anterior part of the kidney, often close to the inferior vena cava ; and they are covered by the testicles, or ovaries.\nIn the Reptilia these organs are much less known, since only isolated (and not unfrequently contradictory) observations have been made respecting them. Hitherto they have not been found among the Derotremate, Pe-rennibranchiate, and C\u00e6cilian orders of this class.\nThe supra-renal capsules of the Saurions have been very eagerly examined, and most exactly in the genus Lacerta. In these animals Nagel found them along the upper extremity of the vas deferens, in the form of two long, small, lobulated bodies. Nagel\u2019s observations have been recently confirmed, and added to, by Ecker. The supra-renal capsules, possessing the form stated by Nagel, have a length of ]i lines, with a breadth of 1^, They lie closely on the vena renalis re-vehens, or on the vena cava ascendens, which is constituted by the two efferent renal veins. Since the right supra-renal capsule is usually of somewhat larger size, it is wont to lie on the vena cava itself ; while the left organ is placed upon the vena renalis revehens. In the male lizard the supra-renal capsules are placed between the vein and the vas deferens ; in the female they are situated between that vessel and the ovary. Numerous blood-vessels convey the blood from it into the corresponding veins. The blind worm (Anguis fragilis) also possesses long, small, supra-renal capsules ; and so, probably, do the Crocodilus Lucius and Ameiva teguixin. Nevertheless, both the latter animals are at present insufficiently examined.\nThe supra-renal capsules of the Ophidia exhibit a similar condition, the more exact knowledge of which we especially owe to Retzius. They form two long and small bodies, and in the Python binistatus they attain a length of 8 lines. The supra-renal","page":828},{"file":"p0829.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\t829\ncapsules of serpents are likewise distinctly tabulated, and very vascular. In other respects, too, the arrangement of the vascular system exhibits much that is interesting ; but to this we shall hereafter return. They always lie closely on the venae renales abdu-centes ; and, according to the course taken by the vessels just named, they are sometimes nearer, sometimes farther from, the testicles and ovary.\nJBatrachia. Formerly many zootomists regarded as supra-renal capsules those peculiar yellow finger-shaped masses of fat, which, in these animals, lie superficially to the kidneys, and possess a connection with the sexual organs, in the periodical increase of which they take a share. Only recently have the true supra-renal capsules been recognised ; and to these the fatty bodies just mentioned have not the remotest resemblance. To Rathke* * * \u00a7, Retzius-J-, Gruby J, and others, we owe the discovery and description of these organs ; the signification of which receives an additional and complete confirmation from minute anatomy, as will be hereafter shown. Here the supra-renal capsules no longer form an organ anatomically defined, but are immediately deposited on the abdominal surface of the substance of the kidneys.\nAmong the tailless Batrachia, they appear in this situation as a golden-yellow streak, which does not extend the whole length of the kidney, but ceases at a distance of one line from its upper, and of two lines from its lower, end. These supra-renal organs also allow a lobular composition to be very distinctly discerned ; and they do not extend along the kidney in a straight line, but usually digress into the arched form. They surround the trunks of the efferent renal veins at their exit from the substance of the kidney ; so that they seem to be, as it were, perforated by this vessel. By a more careful investigation one may satisfy one\u2019s self that the glands are really imbedded in the coats of these vessels. In the tailed Batrachia, on the other hand, we no longer find the supra-renal capsules in the shape of this connected streak, but broken up on all sides into from twenty to thirty separate and irregular lobules. These are seated, partly in the substance of the kidney at its inner border, partly between the kidney and the inferior cava ; while they are also partly deposited on the coats of the latter vessel, and the gland-lobules have the same relation to the efferent renal veins as in the tailless Batrachians.\nFinally, amongst all the orders of Reptilia, the supra-renal capsules are least recognised in the Chelonia. The statements formerly made by Bojanus \u00a7, that the supra-renal cap-\n* Beitrage zur Geschichte der Thierwelt, Dritte Abtheilung, Halle, 1825, S. 34.\n+ Vide the treatise of Nagel.\nj Annales des Sciences Naturelles. Zoologie, Seconde Serie, tom. xvii. p. 209.\n\u00a7 Anatome Testudinis, Wiln\u00e6, 1819\u201421. Folio cum tab.\nsuies were two long bodies, situated at the inner margin of the kidneys, and a similar statement of Nagel *, have been lately corrected by Ecker.f According to the last inquirer, the supra-renal capsules of the Testudo gr\u00e6ca altogether correspond, both as regards form and situation, with the similar organs of the Frog ; since they lie on the abdominal surface of the kidney, imbedded in its mass, and extend almost the whole length of this organ.\nIn Fishes the supra-renal capsules again appear ; but, as regards their situation, form, and number, they are much more diverse than in the other Vertebrata. The supra-renal organs of the cartilaginous fishes were discovered, a long time ago, by Retzius.J For a knowledge of them in the osseous fishes, we are especially indebted to Stannius and Ecker.\nIn the osseous fishes they appear as small, whitish corpuscles, of the size of from a pin\u2019s head to a pea. Their form is, in general, roundish or oval ; their surface is sometimes smooth, sometimes rugged, and broken up into lobules, as is the case in the Pike. According to the observations of Stannius, they have not unfrequently a kidney-shaped form in the Haddock ; and, according to Ecker, they are sometimes triangular in the Salmon.\nThe number and situation of the suprarenal capsules varies greatly in this group of fishes. The presence of two supra-renal capsules ought to be regarded as the rule. They usually lie symmetrically in both halves of the body, as in the higher animals ; they may also occur a-symmetrically, or only in one half of the body, as in the genus Pleuro-nectes ; or they may be behind each other, as in the genus Scomber.\nBut frequently, the supra-renal capsules are present in great number ; in which case their position becomes altogether irregular. Thus one meets with three, four, six, or even more supra-renal organs ; and Ecker has observed as many as six in the Salmon. In the Pike, in which only two to three supra-renal capsules are present in the adult animal, the inquirer just mentioned found that, in a young animal of one foot in length, the whole kidney was beset with a great number of very small suprarenal organs. I have myself remarked the same condition, and occurring exactly in the manner described, in two Pikes of the same size : but, on the other hand, in another instance it was absent.\nAs to the situation of the supra-renal organs in the bony fishes, this also is subject to very great differences. Sometimes these glands lie more on the abdominal, sometimes on the spinal, surface of the kidneys. The former seems more frequently to happen ; and in this case they generally project at the hinder end of the kidney, from the anterior margin of the haemal canal of the inferior\n* Loc. cit.\nf Loc. cit.\nj Observations in Anatomiam Chondroptery-gyiorum. Lund. 1819, 4to.","page":829},{"file":"p0830.txt","language":"en","ocr_en":"830\tSUPRA-RENAL CAPSULES.\nvertebral arch : this occurs in the genera Cyprinus, Tinea, Pleuronectes, Anarrhichas, Scomber. Or they occupy more the middle of the kidney, as in the Salmo Salar. On the other hand, they are found on its abdominal surface in the Eel and Pike. They lie in this situation very anteriorly, occupying, in the Eel, the place where the two crura of the renal mass unite. In the Pike they are yet more advanced forwards, so that they come to lie in the middle point of the length of the body.\nAmongst the cartilaginous fishes, the suprarenal capsules seem in the Squalid\u00e6 to be only present as a single mass. This, in the shape of a small ochre-yellow stripe, occupies the dorsal surface of the kidnejs. But in the Rays the supra-renal organs form a curved cylinder, which is constricted at two points, and lies on the ureters ; at least Retzius formerly stated this to be its condition. Stannius sometimes found in this genus a similar elongated body behind the kidneys : or, in other instances, four or five small glandular corpuscles were present in its place. And the latter observer found that the suprarenal glands of the Sturgeon* consisted of similar corpuscles in much larger number.\nThe supra-renal capsules of the cartilaginous fishes have a yellow colour, and are also plainly lobulated.\nAs has been previously remarked, in the least developed fishes the supra-renal capsules have not been discovered, at least not with any certainty, so that their existence must remain a matter of doubt. In the Myxinoid fishes, J. M\u00fcllerf found behind the gills, and on each side of the cardia, a clustered gland which was devoid of an excretory duct. He interprets it as a supra-renal organ ; and regards as analogous to it the white specks with which the trunks of the posterior veins of the body are beset in the Ammo-c\u00e6tes.J But the minute structure of the glands in question in the Myxinoid fishes, which is also described by M\u00fcller, seems rather to contradict the explanation attempted. And Ecker discovered a gland in the Petro-myzon between the aorta and the great vein of the body, and partly lying in the coat of the latter : but this also had not the structure of a supra-renal capsule.\nII. We next proceed to the minute structure of the supra-renal capsules, concerning which Ecker has given a very good and fundamental description, so that we shall here in great degree follow him. In Man and all the Mammalia, they exhibit two kinds of substance, which have been designated by the names of cortical and medullary substance. The first is clearer than the latter, being in Man of a yellowish-brown colour ; while the\n* Stannius, Lehrbuch der Vergleichender Anatomie der Wirbelthiere, Berlin, 1846, S. 118.\nf Vergleichende Anatomie der Myxinoiden. Schluss. In der Abhandlungen der Academie der Wissenschaften zu Berlin, 1843, S. 118.\nj Rathke, Beitrage zur Geschichte der Thicrwelt, 4te Abtheilung, S. 99.\nmedullary substance possesses a reddish-brown hue. In many instances, the two kinds of substance are little distinguishable by the naked eye, so that the supra-renal capsules exhibit only a simple mass, such as Cuvier has described that of the Elephant to be. Besides this, the amount of the two layers varies very considerably. The cortical substance is of some solidity ; while, on the contrary, the medullary matter is very delicate and flaky. This great delicacy, together with its considerable richness in blood-vessels, makes it very probable, that the medullary substance of the supra-renal capsules is decomposed very quickly after death. And this gives rise to the formation of a cavity, containing a brownish-red fluid, which is not un-frequently found in the interior of the human supra renal capsules. Formerly this cavity was regarded as normal and occurring during life. The name \u201c capsul\u00e6 atrabilari\u00e6\u201d is connected with this notion, since these cavities were described as real by the older anatomists. And although decomposition is regarded as the chief agent in the formation of these cavities, yet pathological conditions seem to be by no means without their influence towards them. Thus Rayer tells us the development of cavities may occur in consequence of rupture of the venous coats, and the effusion of blood in the medullary substance.* Nagel also remarks concerning it, that the supra-renal vein alone, which courses in the centre of the organ, may be instrumental to the production of such a cavity, albeit a small one ; so that by injections through this vein the whole medullary mass may frequently be torn up, and converted into a cavity. The covering of the supra-renal capsules consists of areolar tissue. At many points of this covering little processes of areolar tissue pass directly into the interior of the medullary substance, and thus separate it into portions or lobes of different form and size. These masses of areolar tissue are finally lost in fine bundles, which separate the elementary parts of the gland from each other. We shall return to this again.\nThe further composition of the organ which we are now contemplating is better seen in Man than in any others of the Mammalia.\nFig. 542.\n(After JEcker.')\na, Nucleus of the contents of the supra-renal capsule from an adult man ; b, Nucleus enwrapped in a fine granular mass ; c, Cell ; d, Nuclear-vesicle of an embryo ; e, two gland-vesicles with their contents from an adult.\n* Gazette Medicale, 1838, p. 57.","page":830},{"file":"p0831.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\t831\nIn man the cortical substance appears to be composed of an innumerable quantity of completely shut glandular vesicles, which are united into a mass by the ensheathing-coats previously mentioned. At the first glance one might easily imagine that they were not gland-vesicles, but tubes which, lying close to each other, take a radiating course from the centre towards the periphery. It is only at either margin of the cortical substance that the individual small roundish vesicles can be verified. By more careful examination, we can assure ourselves (as was first stated by Ecker) that this tubular appearance is only apparent, and that it is caused by the glandular vesicles being arranged in rows, so as to cover each other like the tiles of a roof. In this manner the vesicles of a row, especially when they are filled with dark contents, appear like a tube, with a blind termination at each extremity. The observation just mentioned can be best made if the preparation be treated with a dilute solution of an alkali. It will be thus seen that these vesicles of the suprarenal capsules are surrounded by and constructed of a fine, structureless, transparent membrane, to the thickness of which we are unable to assign any measurement, and which, even by the use of the highest magnifying powers of the microscope, appears as only a simple line. This structureless membrane, which modern observers have shown to be a constituent of all glands with the single exception of the liver, we shall indicate by the name of the \u201c membrana propria.\u201d It is especially distinguished by the fact, that it is not attacked by the dilute alkalies, as caustic potash, and ammonia, but preserves exactly its original appearance ; while the contents of the gland are in general completely dissolved by these agents. The use of these applications cannot be too much recommended in examining the glands, as for instance those of the stomach, intestine, &c.\u2014a fact which has been taught me by repeated experiments. The gland-vesicles of the human supra-renal capsules exhibit considerable differences of size; besides which, their form is wont to vary in some degree. The smaller vesicles are roundish, and have a diameter of 8 to 12-1000ths of a line; the larger of these, which seem elongated, have a length of 18 to 25-1000ths of a line, with a breadth of 10 to 15-1000ths. The smallest of these vesicles occur in the greatest numbers at the limits of the medullary substance ; w'hile, on the contrary, the larger and more elongated vesicles generally occupy its middle. The glandular contents, which are surrounded by the vesicles, appear, by a low magnifying power, as a dense pap-like mass, which seems to be white by reflected, and dark by transmitted light, and consist of granules. Nevertheless on the application of a powerful lens four constituents maybe distinguished; namely, \u2014 (1) very fine molecules, (2) fatty granules, (3) nuclei, and finally, (4) cells in different stages of their development.\n(1) The fine elementary granules constitute\nby far the great mass of the contents. They are dissolved by alkalies, but alcohol and ether do not effect their solution, and they are little dissolved by acetic acid ; so that they would thus seem to consist of an albuminous substance, or of a so-called protein-compound. They are immeasurably minute, and in this respect resemble the pulverulent molecules which cause the white colour of the chyle.* Their quantity in the gland-vesicles is so large that they render viscous their fluid contents. It is only on the application of water, that they aggregate themselves into masses or flocculi : previously to this they pervade the viscid fluid with the greatest uniformity. We will select for them the name of pulverulent molecules.\n2.\tThe fatty granules are usually met with in considerable quantity, and sometimes they are very numerous. As may readily be imagined, they are of very different diameters, and range gradually from the smallest granules, through larger ones, to small drops of fat. The yellow colour of the cortical substance is due to this constituent.\n3.\tThe nuclear structures appear urnted into a granular mass. They have an average size of 3 to 4-1000ths of a line, a form which is usually roundish and less frequently oval, and they belong to the variety of the so-called \u201cgranular\u201d nuclei; i. e. to those which are formed of a granular mass, and are not vesicular. The substance of these nuclei is insoluble in dilute acids, but is completely dissolved by the application of potash. Ecker has made the interesting observation, that in the embryo the granular nuclei are no longer to be met with, but that their nuclei are rather vesicles ; that is, that they possess a wall, which encloses a more or less fluid mass, in which are contained one or twro small punc-tiform nucleoli. The same condition also obtains in the nuclei of other embryonal tissues.\n4.\tPart of these nuclei are experiencing a transition to cell development, so as to form a constituent of perfect cells. The metamorphosis to the cell-form begins by a part of the finely granular mass arranging itself around a nucleus. Little clusters are thus formed, each of which contains a nucleus. The outer surface of such a mass then becomes hardened, so that the most superficial molecules form a wall or shell, the cell-membrane; thus the cluster becomes a cell. So that from the fine pulverulent molecules proceed both the cell and the cell-membrane. In conformity with this statement, a microscopic examination of the expressed contents of the gland-vesicles reveals nuclei, surrounded by irregular flocculi of fine granular substance (b, fig. 542.), and other nuclei, around which this latter substance has formed itself into a well-defined, round, or oval mass of 6 to 9-1000ths of a line in diameter ([c,fig. 542.). Finally, other masses\n* Compare with this the experiments of II. M\u00fcller, in Henle und Pfeuffer\u2019s Zeitschrift f\u00fcr rationelle Medizin, 1845, iii. S. 299.","page":831},{"file":"p0832.txt","language":"en","ocr_en":"832\tSUPRA-RENAL CAPSULES.\nmay be seen, on which an enclosing membrane plainly exists.\nThe cell development just described holds good of the supra-renal capsules of all Ver-tebrata. It is thus of very wide distribution. These cells are designated by the name of globules of circumposition (umhullungslcugeln). The so-called granule-cells, or inflammatory globules, belong to the same class ; as also do the globules of fission which originate from the breaking up of the yolk. And I have also observed that the polyhedral pigment cells of the choroid coat of the eye are formed in the same way. Finally (and of immediate interest in this place), I have found that the cells of many other glands are similarly formed ; namely7, the cells of the tubular gastric glands, the glands of Lieberkuhn and of the large intestine, the glands of Brunner, and probably also those which occur in the urinary tubules of the kidney. It may also be conjectured that the cells of other glands will be found to originate in the same way.\nBy a gradual enlargement these cells of the cortical substance are metamorphosed into gland-vesicles (e, Jig. 542.) ; so that while in the large gland-vesicles cells and nuclei occur in numbers, the smaller ones contain only a solitary nucleus. These smallest gland-vesicles are no way distinguishable from the larger cells; they also are cells, and the glandular contents are exactly those of the cell, and the membrana propria is identical with the cell membrane. The contrast between these vesicles and cells \u2014 a contrast upon which Ecker has laid particular stress \u2014 is of little importance. According to this observer, the membrana propria of the vesicle is unchanged by solution of potash, while, on the contrary, the membrane of the cell is dissolved by it. But by a repetition of the experiment one may be assured that it is only a dilute solution which leaves the membrana propria unaffected, and that by a more concentrated solution it is dissolved just as much as the cell-membrane. The difference is thus only quantitative, and is in exact conformity with the gradually increasing hardness of the membrane.\nWhen fine sections of the medullary substance of the human supra-renal capsule are examined with the aid of the microscope, it is seen to be considerably clearer and more transparent than the cortical substance; a circumstance which essentially depends on the fact, that the fatty granules occur more sparingly in the former than in the latter. In Man, and in most of the other Mammalia, it is rendered very distinguishable from the cortical substance by the absence of the gland-vesicles. It is found to consist of a basis of fibrous tissue, which is formed by processes that come off from the sheath of the cortical substance, and in which numerous blood-vessels and nerves take their course. In the mass of areolar tissue the pulverulent molecules above described are also met with ; and besides these, nuclei and cells in different stages of development.\nWhere accessory supra-renal capsules occur, they contain, according to Ecker, the same vesicles ; of which the larger occupy the outside, and the smaller the inside. But the two kinds of substance are not present ; the whole tissue answers to the cortical substance of the real supra-renal capsules, and it has a sometimes clearer, sometimes darker, yellowish appearance.\nThe structure just described obtains with little modification in all the Mammalia. It is true that, at present, only the Carnivora, Ruminantia, Solipeda,andPachydermata, have been examined. Nevertheless, according to these observations, it is tolerably allowable to generalise concerning all the orders of Mammalia.\nIn the Ox, the brown cortical substance is divided by strong bundles of areolar tissue into lobules. The gland-vesicles exhibit nothing extraordinary, but, amongst the different constituents of their contents, the fatty granules are much more sparingly present than in man. Gerlach* found the glandular vesicles very distinct in the Sheep. The structure of the supra-renal capsules of the Goat and Pig is identical with that seen in the Ox.\nIn the Horse, the gland-vesicles of the cortical substance altogether correspond with those of the human subject. Here also the smaller and more spherical lie on the exterior, while the larger and more oval occupy the interior, and offer the tubular disposition already referred to. But their membrana propria is more delicate than in man. In the young Horse the fatty contents of the gland-vesicles are in very small quantity; while, on the other hand, in older animals, it predominates so considerably that it quite conceals all the other contents, and renders their examination very difficult.\nBut the medullary substance in the Horse offers a remarkable distinction from that of the other Mammalia : namely, that it, as well as the cortical substance, contains gland-vesicles. These have a variable shape and size; and are round, oval, elongated, or sometimes curved in the shape of a bow. The contents are the same as usual, only it is much poorer in fat than the cortical substance ; and, on this account, appears much clearer.\nThe supra-renal capsules of the Rodentia and Carnivora possess the greatest quantity of fat, and are therefore the most difficult of examination.\nNotwithstanding this, the white cortical substance of the Rabbit exhibits the usual arrangement : and, besides this, the medullary mass not unfrequently presents small circumscribed collections of fat.\nAmong the beasts of prey, the Dog and Cat have been examined, and in these the nuclei of the contents are with difficulty discoverable, owing to the innumerable quantity of the fatty molecules. The nuclei are here also granular in the older, vesicular in the younger\n* Handbuch der Gewebelehre des Menschlichen K\u00f6rpers, Mainz, 1849, 2tn Lieferung.","page":832},{"file":"p0833.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\n833\nanimals. A portion of fat not \u00bbinfrequently surrounds the cells of the glandular contents ; and in this manner large dark globules originate, which completely obscure the enclosed cell. These may especially be seen in the Cat, where they take a clustered arrangement and occupy the limits of the medullary and cortical substance. The medullary substance is poor in fat. Hitherto the gland-vesicles have not been made out with certainty in this fatty cortical substance, but they are very distinct in the Hedgehog.\nIt yet remains to us to consider the disposition of the blood-vessels, lymphatics, and nerves in the supra-renal capsules of the Mammalia. For this purpose we shall select those of Man.\nVessels. \u2014 In the human subject, each supra-renal capsule is supplied with arterial blood by three trunks : \u2014 by an arteria supra-renalis superior, which is usually present, and comes off as a branch of the phrenica inferior; an arteria supra-renalis media, which is usually double on each side, and arises from the aorta ; and finally, an arteria supra-renalis inferior, which is a branch of the renal artery. The further arrangement of the vascular system has been especially examined by J. M\u00fcller*, and Nagel f, whose results have been recently confirmed by Ecker. J\nThe numerous small arterial trunks having arrived at the outer surface of the supra-renal capsules, take a different distribution. One part of them immediately pierce the sheath of the organ, and enter its substance ; while another portion of them courses for a considerable distance on the outer surface before becoming lost in the interior.\nIn the interior of the organ itself these small arterial trunks still take a different course. One of these sets of vessels can only be followed for a very short extent in the cortical substance. After a course of scarcely half a line in length, they break up into a capillary network, with long meshes, which encircle the gland vesicles of the cortical substance. The other arterial trunks, without giving off any branches, plunge at right angles through the cortical mass into the medullary substance. Here they break up into twigs which, by devious paths, return again into the cortical mass, to end also in a network of capillary vessels. Thus the cortical substance possesses a closer capillary network than the medullary mass, a fact which is in conformity with the predominant glandular activity of the former stratum. Nagel, in his Essay, has illustrated this distribution of the arterial vessels by beautiful drawings.\nThe veins begin at the common margin of the cortex and medulla. They alone constitute almost all the vessels of the latter portion, since the smallest branches gradually unite to form larger ones, and these finally join to form the vena supra-renalis, which\n* Hildebrandt\u2019s Anatomie, herausgegeben von E. H. Weber, 4ter Theil, S. 356.\nf Loc. cit.\nj Loc. cit.\nVOL. IV.\noccupies the middle of the supra-renal capsule ; and, as was stated above, is proportionally very large. \u201c Were we able,\u201d says Nagel,\nto exhibit this venous texture isolated from the cellular tissue which receives it, the individual smaller veins opening into the venous trunk on all sides, and at very acute angles, would render it most suitably comparable to a poplar tree.\u201d\nUsually there is a single vena supra-renalis for each supra-renal capsule. The right suprarenal vein passes immediately from the gland into the vena cava ascendens ; but the left one forms a longer trunk, which opens into the renal vein. But these statements of Nagel are contradicted by others ; for instance, by Krause, according to whom two or three veins generally leave each supra-renal capsule.\nAs far as observations have hitherto gone, this disposition of the vascular system appears to be tolerably constant for all the Mammalia.\nThe lymphatics of the supra-renal capsules are not yet sufficiently known. According to Arnold, there are superficial and deep ones. In animals slain during the digestive act, Ecker could only find the superficial lymphatics, so that Arnold\u2019s statements would seem to be doubtful. The absorbent trunks of the supra-renal capsules unite with those of the kidneys and the internal sexual organs, and they open into the thoracic duct.\nThe uncommonly rich supply of nerves possessed by the supra-renal capsules constitutes a very striking phenomenon, and one which finds no parallel in any cognate organs. In Man, these nerves arise from the c\u00e6liac and renal plexuses in the form of numerous and proportionally large trunks. It is chiefly through Ecker that we have become acquainted with the further course of the nerves in the interior of the organ. Larger and smaller branches of nerves perforate the cortical substance, usually contained in the bundles of its areolar tissue, or accompanying its arterial vessels, but giving off no primitive fibres. Only in the medullary substance do the trunks of nerves break up into bundles of fibres. The neighbouring bundles often exchange their nerve-fibres with each other, so that, in this way, they form a dense microscopic nervous tissue. It would seem that, in the human subject, no ganglion corpuscles are present in this sympathetic nerve tissue ; but, in the Horse, in whom the supra-renal corpuscles are yet richer in nerves than they are in man, some ganglion corpuscles may be seen on the nervous trunks of the tissue. But one must be especially careful against confounding gland-cells of the organ with these ganglion corpuscles, which they superficially resemble. This rich supply of nerves seems only to pertain to the supra-renal capsules of the Mammalia ; in all the other Ver-tebrata, whose supra-rena! capsules, as will be forthwith stated, are very similarly constituted, it is completely wanting. On this account, it becomes exceedingly difficult to state what\n3 h","page":833},{"file":"p0834.txt","language":"en","ocr_en":"834\tSUPRA-RENAL CAPSULES.\nobject is fulfilled by this united condition of the nerve fibres.\nIn Birds, the structure of these vascular glands is even more uniform than in the preceding classes. No separation into cortical and medullary substance appears to occur in any bird. A single observation of Meckel\u2019s states that in the Cassowary the two kinds of substance are to be distinguished ; but this statement is contradicted by the numerous negative observations of Cuvier, Ecker, Bar-deleben, and Nagel, on all the animals of this class which they have examined, and hence it requires a confirmation. The supra-renal capsules of birds appear of a darkish or clearer yellow colour, which, by the varying amount of blood they contain, tends more or less towards red. They are also enclosed in a sheath of areolar tissue, and exhibit a basis which consists of fibrous tissue and bloodvessels. In this matrix the gland-vesicles lie imbedded throughout the whole thickness of the organ, and they are devoid of any regular arrangement. They are of roundish, oval, pear-shaped, or irregular form. Their size varies from 44 to 56-1OOOths of a line, and in the Falco tinnunculus some of them even attain the size of 22-100ths of a line. Their membrana propria is very delicate. The structure here specified may be best witnessed in the supra-renal capsules of large birds ; nevertheless, with some care, we may succeed in recognising the gland-vesicles in the smaller members of the class, as, for instance, in the Pigeon.\nThe contents of their gland-vesicles closely resemble those of the Mammalia. There are the same fine pulverulent molecules of a protein compound ; and fatty granules, which are usually in very large quantity, have a yellowish colour, and give rise to the tint possessed by the whole organ. Not unfrequently larger yellow drops of fat are visible. Besides these, we come upon the granular nuclei previously mentioned, possessing a size of 22 to 31-10,OOOths of a line. Some of these nuclei are also enveloped in a fine granular mass, and exhibit a transition to cells in the mode which we witnessed in the Mammalia. Not unfrequently the nuclei are completely buried in fatty granules, through which they are only visible as clear spots. In the golden Eagle Ecker remarked complete cells filled with fatty granules ; these were probably caused by the usually finely granular cells becoming gradually filled with fat. In many of the gland-vesicles, on the contrary, the fat is remarkably diminished in its proportion to the finely granular substance ; and it has been conjectured by Ecker, and with great probability, that this difference in the amount of fat depends upon the different stages of development of the gland-vesicles. In a very young Pigeon I have found scarcely any fat molecules, a fact which has some connection with this statement.\nThe minute anatomy of the supra-renal capsules of the Beptilia is as yet insufficiently known.\nIn the supra-renal capsules of Lacerta agilis, Ecker was with some difficulty able to recognise the same condition as that seen in the higher Vertebrata; but the presence of a membrana propria around the gland-vesicles was especially indistinct. He only remarked masses of a darkish substance. These masses consisted of fatty granules of the nuclei already described, and of granulated globules, which contained a nucleus, and possessed a size of 31 to 44-10,OOOths of a line.\nIn the Adder, the obscurity of the contents uncommonly aggravates the difficulty of examining their tabulated supra-renal capsules ; but in the foetal Adder of three inches length, Ecker was able to verify the separate gland-vesicles in the usual manner. Here also nuclei were seen; and, besides these, large pale gland-cells, which could not long resist the action of water. Other cells were completely buried in fatty masses, just as they were seen to be in the carnivorous Mammalia.\nThe arrangement of the vessels of the supra-renal capsules is peculiar in the Snakes, inasmuch as the greater part of the blood is not brought to the organ by means of arteries, but by veins. In consequence of this, the supra-renal capsules have a kind of portal venous system, such as is possessed by the kidneys of Reptilia and the liver of Vertebrata. The afferent supra-renal veins arise by two branches from the wall of the body, and from the plexus venosus of the vertebral canal ; and after a tolerably long and isolated course they reach the supra-renal capsules. On an average, the right supra-renal capsule receives two or three branches ; but the left, which is wont to be smaller, only one or two. The arterial blood is brought to the suprarenal capsule by one or two vessels which are branches from the aorta.\nBoth kinds of vessels ramify in the substance of these organs, so as to form a fine capillary network. The efferent supra-renal veins arise from this network in the form of numerous small trunks. They pass from the right supra-renal capsule immediately into the vena cava posterior ; but from that of the left side into the inferior cava, and also into the efferent renal vein.\nIn his examinations of the Testudo gr\u00e6ca, Ecker found certain bodies, which he regards as the supra-renal capsules of the Chclonian reptiles. By microscopic examination, they appear as yellow granules which are grouped together in heaps. Each of these is enclosed in a membrana propria, and thus constitutes a gland-vesicle. Their contents are altogether identical with those of the Batra-chia, to which we shall next apply ourselves.\nIn the tailless Batrachia, the yellow lobules already described consist of groups of vesicles. Their form varies ; sometimes it is round, sometimes oval, sometimes elongated or irregular. The vesicles are always closed, and it is only when they are grouped together that they appear at first sight like blind sacs. Fatty granules constitute the greater part of their contents ; but besides these, the fine","page":834},{"file":"p0835.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\t835\ngranular substance is also present. Clear spots may also be seen glimmering from amidst the contents of the gland, and isolation shows these to be cells of 5 to 9-1000ths of a line in diameter, with finely granular contents and a nucleus. The application of water renders this more visible. Part of these cells are devoid of the cell membrane, but others of them exhibit it very distinctly. Besides these, free nuclei are found ; these are sometimes vesicular and contain a nucleolus, sometimes they appear to be granulated. The nuclei which are included in cells are always of the latter kind.\nFrom these microscopic characters of their contents exactly corresponding with those of the higher Vertebrata, the import of these organs as supra-renal capsules is placed beyond all doubt.\nThe same structure obtains in the tailed Batrachians, only the nuclei and cells are larger, while a part of the latter are completely enclosed in fat. Numerous branches of the afferent renal veins break up anew in the supra-renal capsules, in order to provide it with venous blood, a condition which reminds us of that seen in the Snakes.\nThe minute anatomy of the supra-renal capsules of Fishes is very similar. In the Salmon Ecker found them consisting of separate lobules, which are deposited in a loose areolar tissue perforated by vessels, and which, in addition, receive a special covering of this areolar tissue. Each lobule is composed of a number of large gland-vesicles, from 5 to 11-lOOths of a line in size, which are surrounded by blood-vessels. Their membrana propria is completely structureless. In their contents we again recognise the pulverulent molecules, separate fatty granules, and vesicular and granular nuclei of 2-l000ths of a line in size. The granular substance is rolled around these nuclei in the manner before described ; so that part of them come to notice as spheres without walls, while part are real cells, surrounded by a membrane, and of 7 to 9-lOOths of a line in measurement. It is not unfrequent to find two or three nuclei, instead of one, in their interior. We have remarked an exactly similar condition in the supra-renal capsules of the young Pike ; there is the same fibrous coat, giving off processes which pass into the interior, and thus isolate the gland-vesicles, but the supra-renal organs are less divided into lobules than in the fish previously contemplated. The contents of the gland-vesicles vary according to their size.\nIn the supra-renal capsules which are smallest of all, and measure under 9-100ths of a line, there are no gland-vesicles to be seen, but only nuclei : to these we shall immediately return. But in supra-renal capsules which are somewhat larger, the nuclei are partly included in cells.\nBy a yet further enlargement of these organs, the gland-vesicles also appear : they contain fine molecules, fatty granules, and nuclei. These are vesicular, flat, of circular or irregular form, and vary in size from 22 to\n30-10,000ths of a line. Each of these nuclei contains a single or double nucleolus. Not unfrequently forms appear which may be connected with a division of the nucleus, where it appears cut through the middle, or even incompletely broken up into three parts.\nFinally, the gland-vesicles also contain cells. By enlarging, these cells experience a gradual transition into new gland-vesicles, which are contained within the larger ones ; so that we may distinguish them into mother-vesicles and endogenous daughter-vesicles, just as often happens in other cells, to wit, those of cartilage. The endogenous vesicles occur in the older ones in variable numbers. The smaller gland-cells contain only a single nucleus ; others possess two or three of them, which sometimes lie closely packed on each other. Finally, in other cells, three, four, five, and more nuclei occur ; and in this manner, by an increase in the number of the enclosed nuclei, and at the same time a continual further extension of the cell membrane, the cells experience a transition into glandular vesicles.\nThese conditions, which were first observed by Ecker, and which I can completely confirm from an examination of the same animal, will quite permit us to conclude as follows regarding the development of the glandular vesicles. In the smallest gland-vesicles a multiplication of nuclei takes place, most probably from those already present, by the method of fission. This multiplication extends itself to free nuclei, as well as to those which are included in cells. In the latter case, the cell-membrane must be more and more extended by the formation of the nuclei; and in this manner the cells of a gland-vesicle themselves are changed into new endogenous vesicles. By this process, the mother vesicle itself is considerably extended ; so that, finally, its membrane comes into contact with the sheath of the supra-renal capsule. Finally, after the membrane of the mother vesicle is destroyed new areolar tissue seems to be developed between the secondary vesicles. In this way the small supra-renal capsules of the Pike experience their growth.\nIn large old Pikes, the process of multiplication and growth seems no longer to occur. In their supra-renal capsules, the fibrous foundation is more considerable in quantity, so that by its means the gland-vesicles are more separated from each other.\nSo also in the genus Cyprinus, where a precisely similar structure of the supra-renal capsules may be observed, one lights upon conditions of nuclei in the gland-vesicles which suffice to prove the transition of gland-cells into gland-vesicles. As to the problematical organs of the Myxine and Petromyzon, the glands which M\u00fcller discovered in the Myxi-noid fishes consist of tufts of small elongated lobules, which are clothed with a kind of cylindrical epithelium.* Concerning the glands in\n* See the drawing of this glandular structure in J. M\u00fcller\u2019s Essay.\n3 H 2","page":835},{"file":"p0836.txt","language":"en","ocr_en":"836\tSUPRA-RENAL CAPSULES.\nthe Petromyzon, Ecker only remarks, that the microscopic constituents do not afford any foundation for the view that they are suprarenal capsules.\nHI. Development. \u2014 The supra-renal capsules begin at a very early date of foetal life. In the human subject they appear simultaneously with the kidneys in the seventh week. The mode of their commencement is not yet understood with certainty. Nevertheless there is scarcely any doubt that the statement of Arnold, according to which the supra-renal capsules are formed by a projection of the Wolffian bodies, is erroneous. Most embryologists, as Valentin*, Bischoffj*, and others, find that another method of beginning obtains, namely, that these organs are developed from an independent blastema, which certainly lies very close to the Wolffian bodies, but has nothing at all to do with them. According to Meckel\u2019s observations, both supra-renal capsules constitute at first only a single mass ; and Valentin\u2019s researches on the embryo of the Dog and Sheep harmonise with this statement. But, nevertheless, this opinion may be founded on an error. M\u00fcller found that the supra-renal capsules of a large human foetus at the eighth week were plainly double, only they lay very closely together at their inferior part. Bischoff\u2019s extensive researches on the embryo of Man and other Mammalia, confirm this statement of M\u00fcller, and explain the error of Valentin and Meckel. The embryonal form of the supra-renal capsules in man is distinguished from the later condition by its being composed of large lobes ; and thus, to a great extent, it resembles its permanent condition in some animals.\nIt is highly singular that the human suprarenal capsule in the earlier period of fcetal life, is not only much larger in proportion to the size of the body than it is at a later stage, but that it also considerably exceeds the kidney in size {fig. 543.). This is shown by\nFig. 543.\nFrom, an embryo of 8 lines in length, a, Supra-renal capsule ; b, Kidney; c, Sexual gland ; d, Wolffian bodies.\nnumerous observations of Meckel, M\u00fcller, and others. In a human embryo of the ninth week, Ecker has recently made the same observation. In the embryo of the tenth to the twelfth week, which measures about two inches in length, the kidneys and supra-renal\n* Handbuch der Entwicklungsgeschichte des Menschen, Berlin, 1835.\nt Entwicklungsgeschichte der S\u00e4ugethiere und des Menschen, 1842, S. 291.\ncapsules are for the first time of pretty equal size. While, on the other hand, in the sixth month the kidneys are, as was found by Meckel, already about double the size of the suprarenal capsules, and their weight is to that of these latter as five to two. And as this comparative diminution of the supra-renal capsules proceeds further, the proportions by weight are in the mature embryo as three to one. And even beyond this time, they experience a continual diminution, so that finally, in the adult, the supra-renal capsule is only l-28th the size of the kidney.\nStrange to say, this extraordinary size of these organs during the fcetal period, does not obtain in the other Mammalia. In the earliest period of their embryonal life, the kidneys have always been found considerably larger than the supra-renal capsules. In them both organs appear to grow in precisely equal proportion to each other, so that their (comparative) weight remains the same in the adult animal as in the f\u0153tus. According to Ecker, the supra-renal glands of the new-born kitten are l-56th to 1 -60th the size of the urinary glands. So also the other classes of Vertebrata seem to accord with the Mammalia in this respect. At least Ecker observed, in the embryo and adult animal of the Coluber natrix, the same relative proportion of size between the kidney and supra-renal capsule.\nIf we regard the situation of the supra-renal capsules in the animal kingdom, we shall find a different condition in the different classes.\nIt is well known that the Wolffian bodies begin in the embryo at a very early period, and that these, from their structure and function, must be regarded as the kidneys of the embryo ; so that the name of \u201c primordial or original kidneys,\u201d may be applied to them with all accuracy. Now these primordial kidneys have a very different duration in the different classes of Vertebrata. In Fishes they remain as the urinary glands during the whole of life ; since in them, as Baer and Rathke found, an organ similar to the kidneys of the higher Vertebrata is never developed.\nThe kidneys of Fishes are, therefore, primordial kidneys.\nBut in the three higher classes of Vertebrata the fact is found to be otherwise. Here the primordial kidneys pertain to only a part of the foetal life, and then make way for the true kidneys, which are situated beneath the suprarenal capsules.\nTherefore, the supra-renal capsules of fishes are placed on the Wolffian bodies, while in the other Vertebrata they are in connection with the kidneys.\nIn Man, in whom the supra-renal capsules are at first uncommonly large, the primordial kidneys disappear remarkably early, so that in the second month they have vanished even to the smallest relics.\nThe development of the tissues of these organs is as yet most incompletely known ; at present we have only a single statement of Ecker\u2019s respecting it. In a human embryo of twelve weeks, this anatomist found a very","page":836},{"file":"p0837.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\t837\ndistinct cortical and medullary substance. But only part of the morphological constituents were present ; viz., the elementary granules, fat, and nuclear structures. Cells, with or without a membrane, were only sparingly found ; and gland-vesicles were altogether absent. The embryos of other Mammalia exhibited the same results. In the foetus of an ox of l a feet in length, the vesicles were for the first time detected ; and in this instance, as in those of the mature animals previously described, the gland-vesicles were, according to Ecker\u2019s opinion, developed fi'oin enlarged cells.\nIn any case it is exceedingly interesting to observe, that in spite of the very early foundation of the supra-renal capsule, this organ seems to rest for a considerable time ; since, before their gland-vesicles are developed, we cannot ascribe any activity to the supra-renal capsules. But in man, these vesicles are only developed when the period at which the supra-renal capsules attain their greatest bulk is long passed.\nIV. Physiology.\u2014 Finally we apply ourselves to the functional relations of the suprarenal capsules. Unfortunately, as regards the activity of the glands of blood-vessels, they all veil themselves in an impenetrable obscurity. The recent vast strides of Physiology have passed over them without leaving any traces ; the last ten years having only brought some new hypotheses concerning the function of these organs, and very doubtfully enriched the already great number of older conjectures.\nIt is not the aim of this essay either to answer or to enumerate all that physicians of earlier and later times have imagined as the possible function of the supra-renal capsules. These conjectures, for the most part ephemeral, may be properly left to the history of ana-tomico-physiological science ; and since we willingly disclaim the intention to come forward with a new' hypothesis, we will only call attention to some points of this mass of matter.\nNow that the minute structure of the suprarenal capsules is known, it becomes even more important to dissent from the opinion of Cuvier. He attributed to the supra-renal capsules pretty much the same function as the kidneys,\u201c because these two organs have much similarity with each other, both in their form, and in the tissues of which they are composed.\u201d At present we know how great is the diversity between the tissues of the two organs. Besides, the want of an excretory duct is another fact completely passed over by Cuvier. The opinion of Meckel, that the supra-renal capsules stand in d\u00e9pendance with the sexual functions, rests on just as little foundation, and has been already confuted at length by Nagel in his work. So also the conjecture of Bergmann* and others \u2014according to which the supra-renal capsules stand in a very close relation to the nervous system\n* Bergmann, Dissertatio de glandulis supra-renalibus, Gotting\u00e6, 1839.\nof the foetus \u2014is equally erroneous. We will willingly admit the correctness of the observation, that in brainless monsters the suprarenal capsules are generally deficient ; but we are forced to add, that we cannot annex any distinct notions to this close relation to the nervous system. Besides, this would suppose that the function of the supra-renal capsule differed in the f\u0153tus and in the adult animal ; since certainly no one would seriously defend such a relation of their function in the latter case. And the support which this view seems to receive from the structure of the supra-renal capsules, is likewise only a fallacious one. At one time, attention was drawn to the great richness of the supra-renal capsules in nerves, without reflecting that this is the case in only one out of the four classes of vertebrate animals : and in the same way, the superficial likeness possessed by the gland-cells and ganglion corpuscles was adduced in order to make out the supra-renal capsule as a kind of ganglion. This hypothesis was put aside by the discovery of the gland-vesicles. And especially we would briefly remark, that all those theories which ascribe to the supra-renal capsules a special import during embryonal life, have originated from contemplating them in the human f\u0153tus, in whom they are exceedingly large. Had the supra-renal capsules of other animals been kept in view, those opinions could scarcely have been taken up ; and the special size of these organs in the human embryo would have been recognised for that which it really is, an anomalous, isolated condition, which possibly stands in a causal relation with the swift disappearance of the Wolffian bodies. And, as we have already remarked, even apart from this, the absence of the gland-vesicles from the supra-renal capsules of the small embryo is a fact which must not pass unnoticed.\nWe will, therefore, only attempt to answer such physiological questions concerning the supra-renal capsules which are possibly susceptible of solution, and defer their full understanding to the future.\nWe will see whether the supra-renal capsules in general can be called glands, and how far they correspond with the other glands of blood-vessels, with the thyroid, thymus, and spleen. And then we may answer the question, \u201c whether the supra-renal capsules generally eliminate a glandular secretion, and whether this secretion is to be regarded as similar or diverse in the whole of the vascular glands ?\u201d\nMicroscopic anatomy has taught us to re* cognise three kinds of form under which glands are developed in the higher animals. The first is a fine tube or canal of different length ; the second is a small globular or elongated sac, which is open at one end ; and the third form is that of a globular and completely closed vesicle. A very delicate structureless membrane, the membrana propria, forms the frame-work of all these glands ; and it is distinguished by its insolubility in dilute alkalies. On its exterior, it is surrounded by\n3 h 3","page":837},{"file":"p0838.txt","language":"en","ocr_en":"833\tSUPRA-RENAL CAPSULES.\na network of capillaries, while it includes within its interior, glandular contents in very diverse forms. These contents consist, in general, of elementary granules, of an albuminous material, of fatty granules and small drops of fat, and of nuclei and cells in the most variable quantities. Cells, which are the highest development of glandular contents, are not always found : more frequently only nuclei are noticed. It will be recollected that in speaking of the contents of the supra-renal capsules, we have stated that the development of cells occurs by the method of circumposition of a globular membrane, and the same method obtains in a number of the glands.\nThe first two of the three forms of glands frequently occur isolated, and thus exhibit microscopic glandules of the greatest simplicity ; as for instance the stomach glands of Mammalia, the glands of Lieberkuhn, the cutaneous glands of the Frog. In other instances, glandular tubes or sacs are connected to each other in very variable number, and thus form the larger glands. In this way the kidneys and testicles originate from tubes ; while from sacculi are formed the multitude of clustered glands, as those of Brunner, the salivary glands, and the pancreas.\nThe first two forms of glandular structure have no further interest as regards our present object ; but the case is very different with respect to the third or vesicular form.\nThe gland-vesicles have a very diverse size, ranging from microscopic dimensions to a quarter, a half, or even a whole line or more. Their shape is always spherical, so that their membrana propria encloses a globular cavity, which contains, suspended in a fluid, all the different constituents of gland-contents previously spoken of. In very numerous experiments I have never found vesicles of this kind further divided by ensheathing membranes.\nGenerally the united gland-vesicles are inlaid in the fibrous tissue of the particular mucous membrane of the body ; they are sometimes in greater, sometimes in smaller quantity, so that great differences, both individual and generic, may be noticed in this respect. In many places they occur with greater frequency, so as to constitute the rule, and have therefore received a special name. For instance, the glandul\u00e6 solitari\u00e6 of the intestine, and the lenticular glands of the mucous membrane of the stomach, belong to this category ; while in other cases more than one or even many vesicles of this kind are grouped together to form a glandular body of some extent. Amongst such aggregations may here be enumerated the Peyerian vesicles, which form a single layer of this kind in the mucous membrane of the intestine. We find the same grouping in the ovary, where these vesicles are called \u201c Graafian,\u201d in honour of their discoverer. But here they are somewhat more widely separated from each other by the thickness of a solid fibrous basis, or by the so-called stroma; and they enclose, beside the usual glandular contents, a peculiar body, the primitive egg or ovum.\nThe physiological relations of the gland-vesicles, and especially their duration and origin, are as yet little known. The facts may probably be stated as follows. The gland-vesicles arise from cells which enlarge, so that the cell-membrane becomes the wall of the vesicle, and its contents form those of the vesicle also. At least I have observed exactly this occurrence to take place in formation of vesicles in a fish of very low development which inhabits our brook (Ammocoetes branchialis). In this fish a number of glands of this kind may be found at the dilated part of the intestinal canal, on both sides of it near the spiral fold : these remain tolerably small, although they experience considerable variations of diameter. They are densely filled with large, pale, smooth nuclei, of oval or roundish form, the number of which is greater or smaller according to the size of the vesicle. Beside these are seen in the tissue of the wall of the intestine separate cells, which enclose two nuclei in no way distinguishable from those of the gland-vesicles. From these cells they pass, by all intermediate gradations, to the large vesicles. If one may generalise on this observation, it may be stated therefrom, in accordance with the proposition mentioned above, that the shut gland-vesicles proceed from cells. The gland-vesicles in the mucous membranes of the Mammalia are very unfavourable objects for examination ; so that, unfortunately, in spite of many attempts, I have not been so lucky as to observe their development. So also I am unable to state in what way the multiplication of nuclei takes place, whether by a fission of the nuclei already present, or whether new nuclei arise independently of the old ones in the fluid of the gland. But I conjecture that the latter is the case.\nBy their further increase of size, the gland-vesicles come to lie more on the surface of the substance in which they are imbedded. But the membrana propria does not possess an unlimited extensibility, so that a period arrives when it can no longer withstand the contents, and is burst by them. This rending occurs at the place of least resistance, namely, at the upper and most external part, and engages not only the membrana propria of the gland-vesicle, but also the thin layer of fibrous tissue present superficially to this. By the occurrence of this so-called dehiscence of the gland-vesicles, its fluid contents become effused amongst the other constituents. This process has long been known to occur in the Graafian follicle of the ovary ; but it may also be seen with the greatest.distinctness in the vesicles of the mucous membranes, as well in the separate as in the Peyerian glands. The burst gland-vesicle is thus brought into connection with the outer world, and now resembles a wide-bellied and short-necked flask : it has thus suddenly become converted into a small sac, such as we have already found as a constituent of the glands treated of as belonging to the second variety.\nAfter their dehiscence, the gland-vesicles","page":838},{"file":"p0839.txt","language":"en","ocr_en":"SUPRA-RENAL CAPSULES.\t839\nappear to behave differently. Part of them by bursting arrive at the end of their career. They do not become distended with secretion a second time, but the gland-vesicles cease to exist as such in consequence of further metamorphosis. The ovary, the vesicles of which disappear by the formation of a corpus luteum, affords a proof of the occurrence of this process. While, on the contrary, other gland-vesicles seem to close again, and to become distended with new secretion, in order to their going through the process for a second or perhaps a third time. It is exceedingly difficult to come at the truth respecting this matter, but an examination of the Peyerian glands may afford us some help in the investigation.\nEach Peyerian patch consists of but a single layer of gland-vesicles, which in the adult appear all to be at pretty much the same stage of development. No second row of undeveloped vesicles is ever found beneath this layer, such as might be supposed to serve as a compensation for those which have burst ; so that a Peyerian patch of glands, after all the vesicles had burst, would necessarily disappear, if no closure of the vesicles followed, unless indeed a power existed to develop a new group of vesicles at some other point. Now although the Peyerian glands of Man and Mammalia certainly show individual varieties in number and extent, yet these appear too small to prove a destruction of the Peyerian vesicles after the manner of the Graafian follicles of the ovary. Besides this, I have never been able to remark the least appearance which could lead me to imagine a new development of the 'glandular patches. Moreover, it is a well ascertained fact, that in many Mammalia certain Peyerian gland-patches show a constant position and size at all periods. To this category belongs a very large Peyerian patch which exists in the rabbit at the point where the ileum opens into the large intestine. Such structures will scarce admit of any other conclusion than that the gland-vesicles reclose themselves after their dehiscence.\nFrom these observations, which in part depend on researches not yet published, we shall be able to come to a decision respecting the glandular nature of the supra-renal capsules.\nIn them the same gland-cells appear ; the same membrana propria, capable of withstanding alkalies. Exteriorly this is surrounded by capillaries, and interiorly it contains the same mass, consisting of molecules of a protein substance, fatty granules, nuclei, and cells developed by circumposition of a membrane. We also find a development of gland-vesicles from cells identical with that which was met with in the Ammocoetes, The multiplication of the nuclei here occurs by the method of fission. And since, in the supra-renal capsules, these undeveloped gland-vesicles occur in predominant quantity, we may, therefore, well imagine that the old gland-vesicles are destroyed in these organs, in which they undergo dehiscence. But their contents are not extruded outwardly, as are those of the gland-vesicles\npreviously described, but into the fibrous framework of the organ, in which they exist in the fluid form, and from which they are subsequently received into the vascular system either by immediate or mediate resorption.\nWe are therefore correct in regarding the supra-renal capsules as glandular organs, and their function as secretory; and any hypothesis which ascribes to them a function other than secretory, may be safely considered erroneous.\nIf we now address ourselves to a comparison of the structure of the supra-renal capsules with that of other vascular glands, we shall see how great a resemblance obtains.\nUnfortunately, we do not possess such experimental researches regarding all of them as those which Ecker has published in his work on the supra-renal capsules. Only the thymus gland has found an accurate observer in Simon.* Nevertheless, we already know thus much, that in two of the three other vascular glands, viz., in the thymus and thyroid glands, a similar structure obtains. Bardelebenwas the first to observe what EckerJ, Gerlach\u00a7, Schaffner[j, and others confirmed, that in the thyroid gland gland-vesicles occur grouped in masses, imbedded in a loose cellular tissue, and surrounded by blood-vessels. In Man, they are seen with some difficulty; but are more easily made out in most of the Mammalia, and best in Birds and Reptilia. These vesicles, which attain a size varying from 6-1000ths to 5-100ths of a line, begin as cells which measure 5 to 10-1000ths of a line, and which are connected with them by all the transitional forms. Suspended in a fluid which occupies their interior, are varying numbers of elementary granules of an albuminous material ; and besides these, fatty granules, nuclei of 2 to 3000ths of a line, and finally, cells with one or more nuclei. In the earlier periods of foetal life the vesicles are not to be met with ; but their place is entirely occupied by cells, \u2014 a condition exactly similar to that which was met with in examining the supra-renal capsules.\nSo also the gland-vesicles of the thyroid appear after some time to be destroyed, and their contents resorbed. This is shown by the fact, that frequently only younger and undeveloped forms of these are to be met with in the adult animal ; while in other instances, the fully developed vesicles occur in excessive numbers. Some distinction between the thyroid and supra-renal capsules, although not an important one, may possibly be deduced from the fact, that in most of the Mammalia, the nuclei and cells are ranged as an epithelial stratum on the inner surface of the vesicles, so that the remainder of their cavity\n* A Physiological Essay on the Thymus Gland, London, 1845.\nf Observationes de glandularum ductu excretorio carentium structura, Berolini, 1841.\nt Loc. cit.\n\u00a7 Loc. cit.\n|| Henle und Pfeuffer\u2019s Zeitschrift f\u00fcr rationelle Medizin, 1849.\n3 h d","page":839},{"file":"p0840.txt","language":"en","ocr_en":"810\tSUPRA-RENAL CAPSULES.\nis filled with a more or less clear fluid. Nevertheless, in Man, the gland-vesicles are generally completely filled with the morphological constituents of their contents.\nAs regards the thymus, we have lately had Simon\u2019s researches extended by Ecker, Ger-lach, and Schaffner. The gland-vesicles here likewise enclose similar contents. The quantity of the elementary granules seems to be very variable, and nuclei form the greater part of the contents. In general, cells occur but very sparingly. According to Simon, their number is increased by involution of the organ, in which case, also, fat molecules are wont to appear in place of the elementary granules. As to the gland-vesicles, they deviate from those of the vascular glands hitherto described. In the embryo of the Adder and of Birds, Ecker saw many completely shut gland-vesicles, which everywhere passed into sacculi by pouchings of their membrana propria. In the human thymus, and that of Mammalia generally, only a few vesicles of this kind were found, and the tunics of these exhibited the same condition. Thus the thymus gland exhibits a similarity with the clustered glands ; but is distinguished from these by the want of an excretory duct. And these differences of the gland-vesicles, together with the great number of the nuclear structures, somewhat distinguish the thymus from the supra-renal and thyroid glands.\nThe structure of the spleen is even more different,\u2014if it be allowable to decide upon this organ, which is so uncommonly difficult of examination, from a few observations of a somewhat contradictory tendency. It is only the well-known Malpighian corpuscles which can be regarded as glandular structures. In fact, this opinion would seem to be correct, since Ecker found a delicate membrane enclosing the vesicles. Nevertheless, lately, an opinion has been put forth on many sides, and based on continuous research, that the Malpighian corpuscles are not closed vesicles, but stand in connection with the lymphatics, so as to constitute only vesicular dilatations of these vessels. This view, which is maintained by Gerlach and Schaffner, is especially corroborated by the fact, that the contents of the splenic vesicles differ from those of the other vascular glands, and closely approximate to those of the lymphatic vessels. Thus we remark in their contents, cell nuclei in very predominant quantity, the diameter of which amounts to 2-1000ths of a line. These nuclei appear sometimes smooth, sometimes granular ; they often exhibit one or two nucleoli, while in other instances they have none. Roundish cells of 4 to 5-1000ths of a line, and closely surrounding a nucleus, may also be remarked in sparing quantities. The above-mentioned relation of the Malpighian corpuscles to the lymphatic vessels is probably supported by another circumstance. Another cell formation may be found in almost every spleen, and certainly in the splenic vesicles also. They are large, globular cells, measuring from 5 to IO-lOOOtbs of a line,\nand with contents of a very different kind ; so that from this fact one might conjecture that they form a number of very different structures, which, however, are connected with each other by transitional forms. Thus a part of these cells contain more or less dark elementary granules ; another part enclose larger yellowish, or yellowish brown and tuberculated corpuscles ; while finally, other cells contain, with the latter corpuscles, one or many completely developed blood corpuscles. This group of cells is susceptible of a double interpretation. In the first place, effused blood corpuscles may be enclosed by a cell membrane, and may be broken up into elementary granules in its interior. This view has been taken by K\u00f6lliker*, and is supported by pathological appearances. But the process may be exactly the reverse ; the blood corpuscles may be developed in the interior of the cells, and then, after the bursting of the cell wall, become free. And should this latter view, which is especially maintained by Gerlachf, ultimately turn out to be correct, then we shall have in the Malpighian vesicles of the spleen a new development of blood corpuscles, just such as occurs after another scheme, in the other district of the lymph and chyle system. So that the spleen would be an organ especially serving for the development of blood corpuscles, and the old explanation set forth by Hewson would be the correct one. But if the process be that which K\u00f6lliker supposes, the spleen will exercise the function of destroying the blood corpuscles. In any case, it is worthy of notice, that no such cells containing blood corpuscles occur in the other vascular glands. Gerlach could not discover them in the thymus gland, and they would scarcely have escaped Ecker's careful observations of the supra-renal capsules. So likewise, in a number of examinations of supra-renal capsules, it is impossible to find the least trace of their presence. Therefore by all this the spleen is greatly distinguished from the other vascular glands. Such great differences of structure and contents will not allow us to attribute a like function and a like secretion to all these organs. Certainly we cannot at all state of what kind these differences of secretion are, since the materials prepared by these vascular glands are, as far as regards their composition, completely neglected : but that such differences must exist, I think microscopic research will quite warrant us in saying. In this respect the thyroid gland and supra-renal capsule agree most nearly together, since in general terms, there is a great correspondence in their structure. And, as the spleen is the widest separated from them, so it is not unlikely that future research may remove it from amongst the vascular glands.\nSince the chemical constitution of the secretion is unknown to us, we are unable to\n* Yide Landis\u2019s Dissertation, apparently under K\u00fclliker\u2019s direction, Beitrage zur Lehre \u00fcber die Verrichtungen der Milz, Z\u00fcrich, 1847. See also the article Spleen.\nf Loc. cit.","page":840},{"file":"p0841.txt","language":"en","ocr_en":"SWEAT.\t841\nstate either the object of the vascular glands in general, or that of the supra-renal capsules in particular. Pathological study also has, up to the present time, failed to afford anything which would allow any safe conclusion to be drawn concerning the function of the supra-renal capsules. By their concealed situation, they elude the experiments of the physiologist ; besides this, they are so small, that their secretion can scarcely have any very sudden and visible influence on the vegetative life of the body. So that even by such an eager operative interference as the extirpation of this gland, the wished-for result might scarcely be obtained.\nI therefore repeat, that at present we are completely in the dark as to the function of the supra-renal capsules ; we know not at all in what way they operate, and on this account all references of the supra-renal capsules to this or that organ \u2014 such as have so often been made \u2014 are altogether empty and worthless. We may see at a glance that it would be just as correct to assign a relation of the supra-renal capsules to the eye or ear, as to the sexual or urinary organs.\nEcker, who, in opposition to our view, regards the secretion of all the vascular glands as one and the same, keeps its contents of fat and protein compound especially in view, and conjectures that all the vascular glands are adapted to the formation from the blood of a secretion which is rich in protein and fat, and which being subsequently retaken into the current of the blood, in this manner benefits nutrition. But apart from the fact, that one cannot see why such a fluid should take this round-about way through the vascular glands ; apart from this, the quantity of protein compounds in the secretion of all the vascular glands of the body, even if we take this at the highest estimate,-is far too small to render anv enrichment \u00f6f albuminous materials which the body could obtain in this way other than a very inconsiderable one. The want of an excretory duct affords certainly this information, that the secretion prepared by the vesicles of the vascular glands is again received into the blood ; but evenjdns notion has connected with it much that is obscure and uncertain.\nThe difference of the function of the vascular glands is yet further upheld by the circumstance that their vital duration and activity is different. The function of the thymus is the first to wane ; that of the supra-renal capsules seems likewise much diminished in more advanced age; while, on the contrary, the activity of the spleen endures for the whole life. These organs experience an excessive deposit of fat in their vesicles, and by this means gradually disappear.\n{Heinrich Frey.) *\nSWEAT. \u2014 The cutaneous secretion is formed by the spiral sudoriferous canals discovered by Breschet and Purkinge. In con-\n* The Editor begs to make his acknowledgments to his friend Dr. Brinton for this translation from the German MS. -of ProfessQr Frey.\nsidering this subject it is important to make the distinction between sweat and that exhalation which is constantly, and at the same time insensibly, excreting from the healthy skin. The latter is the manifestation of a function indispensably necessary for the continuance of life; while sweat may be regarded merely as an occasional result, and as producing on the surface certain excretive products which under ordinary conditions only appear in small proportion on the skin, and find their more natural exit from the organism through other channels. It is true that sweat contains among its constituents the ordinary products of the insensible perspiration, but it also contains other matters of a solid kind which do not appear in a fluid form unless cutaneous excitement be brought about, and which in cold weather and in the case of indolent, inactive persons, adhere to the cuticle, and are gradually rubbed or washed off. These solid matters are not volatile at the ordinary temperature of the skin, and therefore will not pass off from the body in material quantity by any amount of perspiration. They become constituents of sweat, however, inasmuch as they dissolve in the water which, under exercise or owing to excessive temperature, appears on the surface. Thus sweat is constituted of the ordinary aqueous products of the natural perspiration, which appearing in large quantity ceases to be vaporised, and in addition it contains those cutaneous secretions which the water dissolves, but which, when an animal does not sweat, appear in less quantity, and adhere undissolved to the surface. As the ordinary cutaneous transpiration forms an important part of sweat, 1 shall proceed to consider it before entering on the more immediate subject of the present article.\nIn the healthy human subject, a portion of water is constantly finding its way to the surface, and under ordinary conditions is vaporised nearly as fast as it is secreted. Some difference is observed in individuals in this respect, however, so that we observe some whose skins are constantly moist, while others, though in perfect health, have the skin almost always dry, yet doubtless performing its ordinary function. Perhaps the most agreeable proportion of perspiration, and that which we should regard as approaching more nearly to the normal quantity, is that which maintains a certain moisture on the surface sufficient to impart an agreeable softness to the touch, and scarcely to convey the idea of moisture. Many attempts have been made to determine the quantity of the cutaneous transpiration, and perhaps nothing has ever been attempted so unpromising in result. It is almost certain, indeed, that we do not transpire equally during any two minutes of the day, and on no two days alike.\nSanctorius, the Venetian physician, whose aphorisms contain much valuable matter, too much neglected by the physiologists of the present day, made lengthened experiments on perspiration. The insensible perspiration has,","page":841},{"file":"p0842.txt","language":"en","ocr_en":"SWEAT.\n842\nindeed, been termed \u201c Sanctorian\u201d in honour of him.\nThis subject, curiously enough, received some attention from the merry monarch Charles the Second, who instituted many experiments on the subject. Among other less exalted, but probably more trustworthy observers, may be mentioned Dodart, Keil, Robinson, Home, and Linings, and of later date Lavoisier and Seguin. According to an experiment of Home, the perspiration during the twelve hours of night varies from 12 to 18 oz., and in 23^ hours the discharge amounted to 3 lbs. 3^ oz. On another occasion, however, the amount was only 2 lbs. 6^ oz. Keil states the medium quantity of perspiration to be 31 oz. only. Robinson states the amount for summer to be 27 oz., and in winter 30 oz. daily. Hartmann, in Germany, makes the daily amount of perspiration 45 to 46 oz. Dodart, in France, gives 40 oz. 3 dr. 26 gr. for summer, and 26 oz. 46 gr. for winter. Sanctorius found that in the warm humid air of Venice, having taken 8 lbs. of ingesta, the perspiration in the 24 hours amounted to 5 lbs., the faeces to 4 oz., and the urine to 69 oz.\nThe observations made by Linings, in the climate of South Carolina, bear importantly on this subject. He found that while perspiration, as might be expected, was most abundant in the warm weather of summer, the urine diminished proportionally, and that the converse pertained for the winter. He observed the perspiration to exceed the urine during seven months, and the urine the perspiration during five months of the twelve. The largest proportion of urine observed was 143 oz., which occurred in December. The largest proportion of perspiration was 130 oz., and was observed in September. The ingesta were to the perspiration as 2*18 to 1. The perspiration of the whole year was to the urine as 1 to 1*08. These experiments differ from those of Sanctorius and Rye, in showing that the urine exceeds the perspiration even in a hot climate.\nOn reviewing all that has been done by various experimenters, it appears doubtful whether, even in warm climates, the cutaneous exhalation exceeds that of the urine, and we ought most probably to regard it as considerably below the quantity stated by Sanctorius. It must be remembered that, as in the experiments described above, the perspiration is estimated from the loss sustained by the body during a given period, after subtracting the weight of faeces and urine discharged ; we have the pulmonary exhalation therefore included in the account, as well as the cutaneous.\nMr. Cruikshank made experiments which are tree from this source of error. He placed his hand in a glass jar, making it air-tight by means of bladder fixed round his wrist and also bound tight to the mouth of the jar. He assumed that his hand presented a surface ^cth that of the whole surface of the body, and from that datum arrived at the conclusion that the exhalation from the skin was 7 lbs.\n6 oz. in the 24 hours, which, under exercise, would amount to 12 lbs.\nMr. Abernethy made an experiment very similar to the above, but according to his calculation, the exhalation for 24 hours would amount only to lbs. This extraordinary difference may perhaps be accounted for by the fact that Mr. Abernethy continued his experiment six hours, and Mr. Cruikshank only one hour, and such being the case, the exhalation may have nearly ceased some length of time before six hours had elapsed, owing to the extremely moist atmosphere in which Mr. A.\u2019s hand was placed. Cruikshank, it will be seen, would have to multiply by 24, and Abernethy by 4 only for the result of 24 hours. Thus the former would magnify the excess (obtained by the first hour affording a dryer atmosphere) into an important quantity.\nLavoisier and Seguin have made excellent experiments with a view of ascertaining the amount of cutaneous exhalation. They enclosed the whole body in a varnished silk bag. There was a small opening to this, which was carefully cemented around the mouth of the subject of experiment. Thus all the moisture from the lungs escaped, while the cutaneous exhalation was confined in the bag. By weighing the body before and after leaving the bag, the total loss from skin and lungs was ascertained. The amount of loss by the lungs was ascertained by weighing the person before he got into the bag and immediately before he left it. After a long series of experiments conducted in this manner, Lavoisier and Seguin found that the mean loss by pulmonary and cutaneous exhalation amounted to 18grs. per minute, or 2 lbs. 13 oz. in 24 hours. Of this the pulmonary discharge was 15 oz., and the cutaneous exhalation 1 lb. 14oz. This they regard, then, as the mean amount of daily perspiration. The greatest quantity of matter perspired in a minute, was 26*25 grs. troy, and the minimum 9 grs. Exhalation is increased by fluids, but not by solid food. It is at its minimum during meals, and at its maximum during digestion.\nUnder certain conditions vapour has been observed to escape from the body in very great quantity. Thus, Haller observed, when in the subterraneous caverns of Clausthal and Rammelsberg, that a distinct cloud or smoke could be perceived rising from the naked human figure.\nSome diversity of opinion has prevailed among experimenters as to the gases which pass off from the body in company with the waterfcby the function of insensible perspiration. Abernethy and Mackensie detected carbonic acid, and Collard de Martigny found nitrogen in addition. These gases appear in variable quantity, and are sometimes altogether absent. After muscular exertion, and after meals, they appear in great abundance. According to Trousset, Barruel, and Ingen-houss, nitrogen is sometimes exhaled without carbonic acid. Monsieur Collard found that the cutaneous transpiration contained most","page":842},{"file":"p0843.txt","language":"en","ocr_en":"SWEAT.\n843\nnitrogen when an animal diet had been used, while carbonic acid prevailed when vegetable food was taken. This experimenter also satisfied himself that carbonic acid was evolved from the skin in a gaseous form, and need not be the result of oxydation of carbon by contact with air, as he was able to collect it over water from the skin. The insensible cutaneous transpiration may be regarded then as composed of aqueous vapour, carbonic acid, and nitrogen gases ; the two latter not only varying in proportion like the first, but probably being sometimes absent, even in health, according to conditions of the organism, which are not yet sufficiently investigated in relation to this subject.\nWhen, under the conditions referred to at the commencement of this article, the surface becomes covered with sweat, the various matters passing away from the skin by excessive secretion have been examined by chemists with the following results : \u2014\nThe total solid matters passing away from the unexcited skin have been calculated at about 7 to 8 scruples in the 24 hours, but the very nature of the inquiry prevents any great reliance being placed in such results.\nWhen sweat is collected, as was done by Simon, from persons subjected to the vapour bath, it appears as a turbid fluid, yielding a deposit by standing. This deposit consists of epithelium scales. The clear fluid was found by Simon to possess a specific gravity of 1003 to 1004. This result, however, must be modified continually by the water condensed on the surface from the aqueous vapour of the bath. The fluid was acid, but only very slightly so, and in the course of twenty-four hours it became neutral. The acidity of the sweat was therefore dependent on the presence of carbonic acid. Ammonia was evolved from it after exposure. Simon analysed his own sweat. He found it to develop an odour of ammonia, and could detect that gas by testing with the vapour of hydrochloric acid. On evaporation, the peculiar smell of animal extractive matter was observed. When the dry matter was triturated with potash, ammonia came off. Sulphuric acid added to another portion developed sulphurous acid at first, and afterwards produced a strong odour of acetic acid. In one instance observed by Simon, the sweat gave off the odour of butyric acid so strongly as to leave no doubt on his mind of the presence of that substance. From various experiments, Simon concludes normal sweat to contain \u2014\n1.\tMatters soluble in ether: traces of fat, sometimes including butyric acid.\n2.\tMatters soluble in alcohol: alcoholic extractive, free lactic or acetic acid, chloride of sodium, lactates and acetates of potash and soda, lactate or hydrochlorate of ammonia.\n3.\tMatter soluble in water : aqueous extractive, phosphate of soda, and, occasionally, alkaline sulphate.\n4.\tMatters insoluble in water : desquamated epithelium, phosphate of lime, and peroxide of iron.\nBerzelius examined and analysed sweat as obtained from the forehead. He found it to contain much the same substances that exist in the acid juice of flesh. He states chloride of sodium to be in excess, however. The skin is certainly an active excreter of free phosphoric and lactic acids, and assists the urine in its important office of discharging these acids from the system. L\u00e4nderer has lately shown the presence of urea in healthy sweat, and it is probably by decomposition of this substance that collected sweat becomes ammoniacal. Thus, the skin would appear, under varying conditions, to assume the excretory duties of the lungs and kidneys, and we are almost constrained to regard its function as supplementary as well as complimentary to that of respiration and the excretion of urine.\nAnselmino has, perhaps, made the best analyses of the sweat. According to him one hundred parts of the solid matters of sweat contain \u2014\n1.\tSubstances insoluble in water and\nalcohol (chiefly calcareous salts)\n2.\tAqueous extractive matter (re-\ngarded as salivary matter by Anselmino, according to Berzelius without sufficient reason), and sulphates\n3.\tSpirituous extractive (chloride of\nsodium and osmazome)\n4.\tAlcoholic extractive (osmazome,\nlactic acid and its salts, regarded by Anselmino as acetic acid and acetates)\nIn order to obtain the solid matters of the sweat, Anselmino collected it in the vapour bath by means of clean sponges. The fluid so obtained was filtered, and the water distilled off. Acetate of ammonia was found in the receiver. Simon considers acetic acid to be a constant constituent of the sweat, and with Berzelius considers hydrochlorate of ammonia to be a normal component of the fluid. Simon, though agreeing in the general with the results of Anselmino, failed to detect sulphates in freshly collected sweat. He found it, however, in the incinerated residue, from which he infers that some of the constituents of sweat contain sulphur.\nThe following is Anselmino\u2019s analysis of sweat in 1000 parts: \u2014\n2-0\n- 21-0\n- 48-0\n- 20-0\nWater -\t-\t- 995-00 Epidermis and calca-\t\t987-500\nreous salts Aqueous extractive\t\u202210\t\u2022250\nmatter (sulphates) Spirituous extractive, chlorides of sodium\t1-05\t2'625\nand potassium Alcoholic extractive, acetates,lactates,and\t2-40\t6-000\nfree acetic acid\t1*45\t3-625\nIn the ash of the dried\tresidue\tof sweat,\nAnselmino found carbonate, sulphate, and phosphate of soda, chloride of sodium, phosphate and carbonate of lime, with traces of iron. In every 100 parts of dry matter of","page":843},{"file":"p0844.txt","language":"en","ocr_en":"844\nSWEAT.\nsweat, he found [22*9 of these fixed saline matters.\nBut little is known concerning the sweat of the lower animals. Fourcroy analysed the white powder which hangs to the coat of the horse when sweat has dried upon it ; he detected urea in that substance, but Anselmino could not. According to the latter chemist, the white matter is made up of the following constituents : \u2014\n1.\tA substance of acid reaction, with an alkaline lactate or acetate.\n2.\tExtractive matter possessing the odour of the animal ; and chloride of sodium.\n3.\tA brown extractive matter soluble in water and pr\u00e9cipitable by infusion of galls, *41kaline chloride and sulphate.\nThe ash consisted of alkaline sulphates anjl chlorides, but no carbonates or phosphates ; phosphate of lime and magnesia, with traces of oxide of iron.\nSweat in disease. \u2014 The sweat in disease has been submitted to examination in a very unsatisfactory manner, but\tfew\tanalyses\nhaving been made. Dr. Piutti, of Elgersburg, made analyses of the sweat obtained from three patients w'ho were undergoing the water cure, and obtained the following results : \u2014\n1. Patient suffering from chronic gout, sp. gravity of the sweat 1003*5.\nWater -\t-_\t-\t-\t-\t995*5\nChloride of sodium -\t3*0\nPhosphate of ammonia -\t-\t\u20195\nAcetate of ammonia -\t\u20185\nHydrosulphate of ammonia\t-\ta\ttrace\nExtractive matters\t-\t-\t'5\n1000-\n2. Patient the subject of gout during six years, sp. gravity of the sweat 1004.\nWater -\t-\t-\t-\t993*0\nChloride of sodium\t-\t-\t4*0\nPhosphate of ammonia\t-\t-\t0*8\nAcetate of ammonia\t-\t-\t0*6\nHydrosulphate of ammonia - a trace Extractive matters\t-\t-\t1*6\n1000*\n3. Patient suffering from paraplegia, otherwise healthy, sp. gravity of\nthe sweat 1003.\nWater -\t-\t994*6\nChloride of sodium\t-\t-\t3*3\nPhosphate of ammonia\t-\t-\t1*1\nAcetate of ammonia\t-\t-\t0*5\nllydrosulphate of ammonia - a trace Extractive matters\t-\t-\t0*5\n1000*\nThe animal matter possessed a green colour in this case. Soluble in ether, but not in alcohol.\nThe perspiration in different forms of disease possesses a peculiar odour, and many very fanciful opinions have been given on this point. Scabies is said to afford a mouldy odour; jaundice is musky, and syphilis\nsweet. In ague, the odour of fresh-baked brown bread is said to pass from the skin. Stark states that the quantity of lactic acid is increased in the sweat in scrofula, rhachitis, and some cutaneous eruptions.\nProut noticed an increase in the quantity of salts in sweat in a case of dropsy. An excess of salts has also been noticed by Anselmino in a severe case of gout. It has been said that in cases of gouty and urinary concretions the quantity of phosphate of lime is increased. As regards the latter form of disease, there is no good reason to believe the opinion above stated to be true.\nA great increase of lactic acid is observed in cases of rheumatism and gout ; the sweat in such cases is always extremely acid. Anselmino, however, states, that he has observed the sweat after a gouty attack has passed off, containing a large proportion of ammonia. Anselmino and Stark state that they have detected albumen in sweat ; the former in rheumatic fever, the latter in gastric, putrid, and hectic diseases, and in cases generally immediately before death. Simon could not detect it in sweat which he obtained from the breast of a person suffering from phthisis in the colliquative stage.\nFat is also said to be found in large quantity in colliquative sweats. Bilin and biliary colouring matter, or biliph\u00e6in, have been found in the sweat of icteric persons. Berend says he has observed it in bilious fevers.\nVoigtei states, that he observed blood to sweat from under the arm of a young man after violent exertion. Such perspiration is also said to have been observed in scurvy and low typhus fever. Uric acid has been found in the sw-eat of gouty patients, probably in the form of urate of soda.\nL\u00e4nderer observed a red-coloured sweat in a fever patient\u2019s axilla, which he believes to have contained the red colouring matter of the urine (uroerythrin). Blue perspiration has been noticed by several writers. Dr. Bleifuss noticed it coming from the foot of a patient suffering from abdominal disease. Michel noticed it in hysteria and hypochondriasis. Sugar has been detected in the perspiration of persons affected with diabetes, by Nasse. Various substances used internally as medicines, as articles of diet, or taken for the purpose of experiment, have been recognised in the sweat. These are, according to Stark, sulphur, mercury, iodine, iodide of potassium, assafcetida, garlic, saffron, olive oil, rhubarb, indigo, Prussian blue, and copper.\nL\u00e4nderer observed, that if he took quina his sweat became bitter.\nIn cases of Morbus Brightii I have been able more than once to detect urea in the perspiration, and I am inclined to believe it constantly present both in cases of suppression and retention of urine.\nI have stated that experiments lately made by L\u00e4nderer, the Athenian chemist, have proved urea to exist in the sweat in health. If this be proved, we of course can no longer regard it as an abnormal constituent of that","page":844},{"file":"p0845.txt","language":"en","ocr_en":"845\nSYMMETRY.\nfluid, but must look upon it merely as present in excess in the diseases above alluded to.\n(G. Owen Rees.')\nSYMMETRY (<rw\u2014fierpov). In its general acceptation this word means a just and harmonious proportionment of parts to one another and to their whole ; in anatomy, however, it has a different and more restricted meaning. With its anatomical signification alone I have now to deal, and that may be defined as follows : \u2014 Symmetry is a word used to express an idea that would be more correctly represented by a verb than a noun, for it is the idea of not a thing but a fact \u2014 the fact, namely, that one half of an animal is usually an exact reversed copy of the other\u2014 the right side is a reversed copy, or repetition, of the left. To this there are numerous exceptions, even in the human subject ; of which hereafter.\nThat unreversed serial copying or repetition which is observable, for instance, between the scapular and pelvic limbs, is enunciated by the analogous expression serial homology. The point on which a distinction may be made between symmetry and homology, is that of the reversing of the copy or repetition as characteristic of the latter. This characteristic seems to impress one with the notion that the two halves are parts of a whole, whereas an un reversed serial recurrence of similar parts inclines one to accord a kind of separate individuality to each repetition. A clear distinction between these two styles of repetition ought undoubtedly to be firmly impressed and maintained on the mind. I have, however, for want of a convenient inflection of the word under consideration, at the risk of some confusion, been long accustomed to use the expression lateral homology in reference to symmetrical repetition \u2014 and in that sensei shall have to use it in this article.\nWhether the word symmetry should be applied to that antero-posterior repetition which is met with in caudal vertebrae of fishes, for instance, is not yet determined by usage, and it will be sufficient for me hereafter simply to make my remarks upon the apparent existence of it. In so doing I shall use the expression antero-posterior homology in a sense precisely parallel to that of lateral homology.\nLateral Repetition.\u2014That the right hand and foot, and the right side of the head and trunk, are the exact counterpart of the left is a fact so obvious, that merely to assert it seems an unnecessary truism. It should, however, by no means be regarded as a matter of course. It might have been otherwise.\nThe human skeleton is, normally, perfectly symmetrical in all its details, and so are the skeletons of all vertebrate animals, with the exception of the Pleuronectid\u00e6, or flat fishes, noticed hereafter. The archetype or abstract ideal figure of an osseous vertebral segment, as that of Prof. Owen, at vol. iii. p. 824., is a symmetrical form. But it is doubtful whether any single bone in the skeleton should be regarded as primordially mesial and symmetrical\n\u2014 whether any ossifie point is originally in the middle line. The ideal archetype of the above illustrious author contains three mesial azygos elements, viz. the haemal and neural spines and centrum ; but it has always appeared to me that each of these elements should be represented in the ideal by a pair of pieces, because each of them is occasionally represented in nature by a pair of bones : Prof. Owen, for instance, regards the two parietal bones as the neural spine of a vertebra. Though there is no difficulty in conceiving the coalescence of any number of pieces into one, and though it is easy to conceive that this coalescence may have occurred before the commencement of ossification, so that two or more of the points destined to become the centres of the ossifying process may be brought so close together as, when manifest by the earthy deposit, to appear but as one, yet it is not possible to conceive that two pieces can be developed from one ossifie point. The single azygos condition may proceed from the double, but the double cannot proceed from the single ; therefore the double condition must be regarded as the primordial, and should hold place in the abstract type. There are occasionally met with certain monstrosities which seem to show in a remarkable manner that a vertebra is composed of two lateral halves that are primordially separate. Thus, in double-headed monsters, wherein there are two vertebral columns above, which coalesce and form one below, the half of each of the two columns which is adjacent to the other seems to be lost at the point of coalescence, and the single column below this point seems to be composed of the right half of the one and the left half of the other of the two columns. In the skeleton of the Boa Constrictor preserved in the Hunterian Museum, there are two vertebrae that are double on the right side and single on the left, bearing two ribs on the right side and only one on the left ; or rather there are two specimens of right halves of vertebrae, existing independently, which are anchylosed, the one to the vertebra in advance of it, the other to the one behind it. This anchylosis alone justifies the expression \u201cvertebrae double on the right side but in neither instance is it so complete as by any means to mask the real nature of the independent half vertebra. Such facts as these, especially the existence of one half of a vertebra without the other, even seem, in contradiction to the impression stated above, to claim for each half of a vertebral segment the importance of a separate individuality, such as is accorded to each vertebral segment itself. They seem to show that a vertebra is as much a compound of two lateral parts symmetrically repeating one another, as the human spinal column is a compound of thirty-three serial repetitions of vertebrae. The fact of the lateral halves being reversed copies of one another, I am disposed to regard as proof of their being parts only of a whole, and as disentitling them to an individuality like that which we are accustomed to assign to unreversed serial repetitions; it","page":845},{"file":"p0846.txt","language":"en","ocr_en":"846\nSYMMETRY.\nmay, however, be regarded as not sufficient proof of this. The value to be given to such facts depends, here as elsewhere, upon the peculiar bias of different minds, and the associations that pre-occupy them. It is not necessary in the present state of our knowledge, nay, it is not expedient, to bind the mind down to this or that view of the facts that come before it.\nA remark, en passant, is due to the consideration that the corresponding organs and parts of organs of the two sides are not only similar in form and structure, but normally of exactly the same age. The corresponding ossifie points of each side make their appearance at precisely the same time, and in all respects the original development and subsequent evolution and maturation of the embryo proceed exactly pari passu. The exceptions alone to this rule of symmetry will chiefly occupy our consideration.\nIn Man, except perhaps in the very early stages of his existence, exceptions are offered by the heart, great blood-vessels, lymphatics of the trunk, lungs, bowels, liver, spleen, and pancreas, with their appendages. All these parts were in all probability, in the very earliest stages of the embryo, symmetrical ; most of them have been proved by actual observation to have been so ; it is, however, difficult to conceive this to have been the case with the following other instances of departure from symmetry.\nAll decussations in the middle line are a-symmetrical. Indeed, if a fibre crosses the median line anyhow but at right angles, there is a departure from symmetry. Consequently, the decussation of the optic nerves, the decussation of fibres in the medulla oblongata, and the decussation of white fibres at the linea alba, are instances of exceptions to symmetrical repetition. One is tempted, in the last instance especially, to believe that these decussations are not in the original embryonic pattern or plan ; but that they are developed subsequently, in obedience to subsequent circumstances : the knowledge of the power which circumstances, external or internal, existing at any period of an animal\u2019s life, have in modifying the directions of fibres of areolar tissue, and of affecting it in other ways, aids one in this belief.\nThe most remarkable of the above instances, and that in which the primordial symmetry is most widely departed from, is the heart and the great blood-vessels that are immediately connected with it. The heart first makes its appearance as a mass of cells posited in the middle line, which soon becomes hollow and divided into three compartments, the lower one of which receives the embryonic veins, and is therefore the auricle, whilst the upper one is the commencement of the aorta, or bulbus arteriosus. The middle cavity (the ventricle) becomes bent into a horse-shoe form, so as to bring the auricle and bulbus into apposition. From the latter proceeds a median artery, giving oft\u2019 six arches on each side that surround the space occupied by\nthe digestive canal and converge towards the spine, where they are received by two symmetrical aort\u00e6. The vein that enters the auricle is a canal or sinus, that intercommunicates between two venous trunks symmetrically placed on each side of the spine, called ductus Cuvieri, the posterior continuation of which is the cardinal (future azygos and hemi-azygos) veins ; and the anterior, the jugular. One of these ductus is permanent as the superior cava. The omphalo-mesenteric vein, which empties into the auricle, is at this time situated in the middle line between and in front of the cardinal veins, and into it falls the single mesial vena cava descendons. The precise periods at which these parts are first discernible, and those at which the changes about to be described take place, will be given in the article Ovum. It is the manner of their metamorphosis alone that bears upon this present inquiry. So far all is symmetrical ; now commence those changes whereby the adult impar arrangement is eventually effected. The fourth and fifth (from the heart) pairs of aortic arches (the two anterior pairs), and the right one of the second pair, soon disappear. The left one of the second pair is permanent as the arch of the aorta, and the third pair persist as the subclavian arteries. The first pair give off branches to the nascent lungs. Meantime, the lower (abdominal) parts of the aort\u00e6 have coalesced, and those parts of them which intervene between the second arch on the left side (the arch of the aorta) and the third (the left subclavian), and between the first arch of the right side (right pulmonary artery) and the third (right subclavian), disappear. Now we have, on the left side, the first two arches uniting behind to form the left aorta. The first gives off a branch to the lungs, and that portion of it which is beyond this pulmonic branch remains, as the ductus arteriosus, pervious till birth ; whilst that portion which is nearest to the heart remains, in connection with the pulmonic branch, permanent for life as the left pulmonary artery. On the right side the first arch alone, the second having previously disappeared, forms the right aorta, which soon joins its fellow with which it coalesces below. The proximal part of this arch is permanent, and remains in connection with its pulmonic branch as the right pulmonary artery, whilst the part of it beyond the pulmonic branch, together with its continuation, the right aorta, down to its point of junction with its fellow, soon disappears. A septum, meanwhile, has been developed in the ventricle of the heart, dividing it into right and left ventricles, and an imperfect one in the auricle. The bulbus arteriosus also has been divided by a septum, in such a manner that the first pair of arches remains in connection with one division of it, which communicates with one of the ventricles, whilst the permanent left arch of the second pair communicates with the other division, and through it with the other ventricle. It is most probable that these septa, when first developed, extend from side to","page":846},{"file":"p0847.txt","language":"en","ocr_en":"SYMMETRY.\nside, consequently that the systemic ventricle and aorta are at first in front of the pulmonary ventricle and artery, and that the heart subsequently undergoes a twist towards the right, carrying the systemic ventricle round behind to its permanent position on the left. In reptiles, in which a great many other of the mammalian foetal characters are permanent, the root of the systemic is in front of that of the pulmonic artery, and there is not that twining round one another of the great arterial trunks which is met with in man. Thus, then, these, the most unsymmetrical parts of the whole body, can be proved by actual observation to have been originally perfectly symmetrical, and the manner of their attainment to their ultimate unsymmetrical form can be accurately traced.\nThe a-symmetry of the lungs is little more than a trifling difference of size between the two, dependent upon the encroachment of the heart by its displacement towards the left. And the a-symmetry of the great abdominal viscera enumerated above, and of their appendages, depends entirely upon lateral displacement and excesses of growth of one side over the other, having reference to convenience of packing. This a-symmetry, greater in mammalia than in reptiles and fishes, on account of the presence of the diaphragm, which, so to speak, thrusts the abdominal viscera downwards, necessitating lateral displacement, attains its acme in man, owing to the great lateral measurement compared with the antero-posterior distance which is so conspicuous in his figure when contrasted with that of other animals. The hepatic attachments of the falciform ligament and g astro-splenic omentum landmark the original median line of the liver ; and that larger part of it which is to the right of the ligament and behind the omentum, is the right lateral homologue of that lesser part which is to the left of the ligament and in front of the omentum. The gall-bladder appears to be an unsymmetrical organ, situated to the right of the median line. I am unable to state whether or not a left gall-bladder has once existed and been suppressed, or whether it is a diverticular production of the gall-duct evolved subsequently to the first sketching of the embryo ; or, lastly, whether it is originally median and subsequently displaced. The anterior wall of the stomach is the left lateral homologue of the posterior wall. The spleen is an originally median organ, situated in the originally median meso-gastrium. The] great omentum is a pouching out of the meso-gastrium towards the left, consequently its outer surface is the left lateral homologue of its inner surface.* The pancreas is an originally median organ, one end of which has been displaced along with the pylorus towards the right, so that its anterior aspect is the left lateral homologue of the posterior. The intestinal canal can be witnessed in the embryo as a straight, uniform, mesial, and symmetrical\n* See Peritoneum.\n847\ntube, until its length having become greater than that of the region which it is destined to occupy, it is compelled to arrange itself in gyrations and loops. The posterior and anterior walls of the stomach were originally, as indicated above, its right and left halves ; and as to the other parts of the alimentary tube, whatever difficulty there is in recognising the manner of their displacement in the human subject, is at once dispelled by examining their condition in the lower animals. No difficulty whatever is encountered in respect of the small intestines, for their mesentery is attached nearly in the median line ; the bowels themselves, however, are continually varying their position, relative and positive, according to the manner of packing most convenient for their variable contents. Not so easy is it to understand the kind of displacement which has taken place in respect of the large intestines. The colon is curled back, and crosses over the small intestine from right to left, forming a loop. In the human subject, the true relation of these parts is further masked by the singular circumstance of this crossing over occurring just at the point where the meso-gastrium, after having descended as the great omental bag, is returning to the spine, and the colon, finding it there, so to speak, avails itself of it, and uses it as a mesentery ; anatomists have named this borrowed portion of the meso-~ gastrium the transverse meso-colon. In Ruminants the colon, being exceedingly long, avails itself also of the mesentery of the small intestines, into which a loop of it is thrust further and further until it makes three turns ; so that in tracing the colon onwards with the finger, you make three spiral turns' in the mesentery, and then double and return by three spiral turns placed between the former spirals.* On the other hand, in the Carnivora, where the colon is very short, it crosses over the lower end of the ileum so near to its termination that it is evident that the next degree of shortening must result in the continuation of the small and large intestines in a straight line. This actually takes place in the Reptilia f, and then there is no longer any difficulty in recognising the original mesial and symmetrical position of the intestinal tube and its appendages, so displaced in the human subject as to make this recognition so extremely difficult.\nIt is by no means uncommon to meet with instances where all the unsymmetri-caliy posited organs of the human body are placed completely vice versa to their usual situations; the heart pointing towards the right ; its pulmonic to the left of its systemic ventricle; the vena cava to the left of the aorta ; the liver in the left, and the spleen in the right hypochondrium; and the c\u00e6cum in the left iliac fossa. Almost every anatomical museum contains an instance of this kind ; and in all instances where the history of the case before death was known, the average health\n* See Ruminantia.\nf Seeflg. 491. Yol. III. Peritoneum.","page":847},{"file":"p0848.txt","language":"en","ocr_en":"848\nSYMMETRY.\nand ordinarily well-developed state of the subject attested the insignificance of this transposition in respect to the well-being of the individual. Such cases are most interesting from this consideration,\u2014that all the unsym-metrical organs are transposed. There is, I believe, no instance on record of one, or two, or less than the whole of the unsymmetrical organs occupying the side which is not their usual one. This prompts the belief that the side which these organs shall respectively occupy is determined by a single impulse first given to one of them.\nAbnormal deviations from symmetry are of extremely frequent occurrence. The bloodvessels of the body are very rarely perfectly symmetrical. In the adult subject the two sides of the body rarely match exactly, in external form. The right hand is usually larger than the left. Accidental circumstances occurring to an individual frequently disturb the symmetry, but it is by no means uncommon to meet with evidence of hereditary transmission of aberrations from symmetry. Such monstrosities as supernumerary fingers and toes are sometimes symmetrical, but just as frequently, perhaps more frequently, the monstrosity exists on one side alone.\nComparative Anatomy.\u2014I pass on now hastily to notice such deviations from symmetry as are met with in the normal conditions of the lower animals belonging to the vertebrate sub-kingdom, and to examine the question of symmetry in the other sub-kingdoms.\nIn all Mammalia there is much the same departure from symmetry in the viscera of the chest and abdomen as is found in the human subject ; but in no other mammal is the lateral displacement so great as in man, for in all others there is a greater proportionate anteroposterior depth of chest and belly. The only other notable instances of a-symmetry known to exist in the mammalian class are the following : \u2014\u25a0 In the male narwhal or sea-unicorn the left front incisor tooth attains the enormous length of eight or ten feet, while the right one is found as a rudiment that never pierces the gum. Spirals in the middle line are departures from symmetry ; consequently the spiral penis of the boar, &c. must be regarded as instances of a-symmetry ; a slight excess in length of one of the halves is sufficient to produce this spiral form. The left nostril of most of the Cetacea is constantly much larger than the right.\nIn Birds there is much the same want of symmetry in the viscera of the trunk as is met with in mammals. The right one of the second pair of embryonic aortic arches however is retained instead of the left, so that the adult aorta arches over the right bronchus. But notwithstanding this, the left ventricle is the systemic one, and presents the same excess over the right, in the thickness of its walls, as in Mammalia. Both of the ductus Cuvieri are retained and form two superior ven\u0153 cav\u00e6. The liver is situated mesially, that is to say, its great fissure and falciform ligament are in the middle line ; but its left lobe is usually the\nlarger, and in the common fowl presents a fissure which is not repeated in the right. The oesophagus diverges slightly towards the light, but the cardiac orifice of the stomach is to the left of the pyloric. The long loop described by the duodenum, and the pancreas which is surrounded by it, are found extending diagonally across the abdomen in front of the other bowels, their extremity resting in the left iliac fossa, but they are not fixed in this position. The gall bladder is situated as in Mammalia. There being no great omentum, the spleen occupies its typical position behind the stomach. There is usually a disparity in the length of the pair of caeca met with in this class.\nBut the most remarkable exception to symmetry in the class Aves is that which exists in thefemale generative organs. The left ovary and oviduct alone are functionally evolved, whilst the right, becoming atrophied at an early period, are barely traceable in the adult animal. A few instances are on record where these right lateral homologues of the ovary and oviduct have been found evolved in functional size as a testicle and vas deferens, thus forming lateral hermaphrodism.\nThe male generative organs of birds are all symmetrical except the penis, when it exists, which is spiral.\nAnother instance of want of symmetry is presented by the beak of some birds, as the cross-bill, &c.\nReptiles. \u2014 The heart of reptiles is situated in the middle line, but it is not symmetrical in form, nor do the great blood-vessels enter and quit it in a perfectly symmetrical manner ; they however approach more nearly to symmetry in this class than in any of those which have been previously considered. In all reptiles there are at first two aort\u00e6, symmetrically disposed, arching over the right and left bronchi respectively, and uniting with one another to form one trunk on the spine. The vessels given off from these are, however, most generally not symmetrical, the head and front limbs being supplied frequently from the right arch alone, and the chylopoietic viscera from the left alone. The pulmonary arteries arise behind the origin of the aort\u00e6. The lungs of reptiles are usually two symmetrical organs, but in the Ophidia the left lung, when it exists, is much shorter than the right, and in some, as Coluber thiringicus, it is wanting altogether, the only vestige of it being a caecal depression on the left side of the lower end of the trachea ; this absence of the left lung entails, of course, the loss of the left pulmonary vessels.\nThe stomach and bowels of the Chelonia, owing to the flattened form of the animals, are nearly as much laterally displaced as in the human subject. In the other reptiles they are not much out of symmetry, yet in none are they exactly symmetrical. The cardiac end of the stomach tends, though often but a little, towards the left ; the pyloric is free, and can be brought without violence to the middle line, but yet it is always found","page":848},{"file":"p0849.txt","language":"en","ocr_en":"849\nSYMMETRY.\nleaning to the right. This renders the spleen more conspicuous on the left. The liver of reptiles extends from side to side, but the right lobe is the largest.*\nIn the tadpoles of toads and frogs, I have observed that there is no gill opening on the right side. In the Lepido-siren the anus is situated on the right side of the mesial ridge of the tail.\nFishes. \u2014 The heart of fishes is posited symmetrically, but the relative position of the auricle and ventricle is usually unsymmetrical, the former being behind and to the left side of the latter. The single arterial trunk, with its branchial arches and the coalescing aort\u00e6, however, are precisely alike on both sides. The intestinal canal, being generally much longer than the abdomen of the fish, is necessitated to throw itself into unsymmetrical loops and convolutions.\nThere is a very remarkable departure from symmetry in all the members of the group of fishes called Pleuronectid\u0153, or flat fishes, such as the turbot, halibut, sole, and flounder. These fishes lie at the bottom, and swim, on one side ; and the side which they keep uppermost is coloured dark like the back of other fishes, whilst that which they keep undermost is white like another fish\u2019s belly. The dark-coloured side is also somewhat convex, whilst the white side is nearly flat. The dorsal azygos fin is continued on to the head, beyond the eyes, almost to the muzzle, and, what is most remarkable of all, both the eyes appear on the dark side, and are actually both situated on one side of the dorsal azygos fin. With the exception of the different colour of the skin, the different degrees of convexity of the two sides, and a slight distortion of the mouth, the whole of these fishes are symmetrical in all their parts, besides the eyes and the structures immediately surrounding them. The bones immediately contiguous to the eyes suffer the following remarkable distortion : \u2014 The occipital bone is almost perfectly symmetrical, and its mesial crest is continued far forward as a sagittal crest between the parietals in the real as well as the apparent middle line, supporting the styliform bones to which the rays of the dorsal azygos fin are articulated. There is a slight difference in the size of the parietals, that of the right or white side being the largest ; but it is the frontal and pre-frontal bones that suffer the greatest distortion- Arriving at the frontals, the real or primordial middle line is suddenly deflected towards the left or dark side, whilst the sagittal crest, still supporting the azygos fin, is continued straight on, on the right frontal alone. The left frontal is less expanded, but more clumsy than the right, and extends forwards in a curved form between the eyes, presenting a concavity towards the right. To this concave curve is sutured a falciform process produced from the left anterior corner of the right frontal, which is quadrate. This suture of course indicates the real middle line. The eyes are situated on each side of the sep-* Vol. IY. fig. 220. p. 304. art. Reptilia.\nVOL. IV.\nturn thus formed. The end of this compound septum rests on the suture between the two pre-frontals, and this suture, which again indicates the real mesial line, presently regains the apparent middle. The right pre-frontal is much larger than the left, and comes again into contact with the right frontal on the outside of the right eye, which therefore occupies an orbit with a complete bony margin, whilst, the same thing not occurring on the left, the eye of that side has no orbit, but seems to lie loose in the soft structures of the cheek. The symmetry of the base of the skull is disturbed but slightly, the long sphenoid and vomer forming nearly a straight line, and participating but slightly in the abrupt deflection of the middle line which takes place above. Not the least curious part of this history is the non-participation of the dorsal azygos fin in tlje deflection of the mesial line : it furnishes an additional proof that its rays are not a part of the endo-skeleton. The eyes of the pleuronects are of different sizes ; the furthest from the dorsal fin (the left, the one that has no orbit) being the smallest, and the optic nerve and optic lobes of the brain, which belong to it, are smaller than their fellows.*\nIn using the terms right and left in the above descriptions, I have constantly had in view the turbot, which is coloured, and shows its eyes on the left side ; but the sole, dab, and flounder, are coloured on the right, and therefore those terms must be reversed when applied to them. It is extremely common to meet with individual specimens of Pleuro-nectid\u00e6 coloured, so to speak, on the wrong side, that is to say, not on that side which is usual, and the rule for the species. Turbots coloured, and having their eyes on their right sides, are frequently met with, and the flounders brought to the London market are almost as frequently coloured, and show their eyes, on the left as on the right side. The un-symmetrically posited intestines of these fishes do not participate in this transposition, but occupy, respectively, the same sides in the monstrous as in the normal individuals. The frequency of these monstrosities tempts one to conjecture that external circumstances may, perhaps, determine which side of the pleuronect shall have the eyes and be coloured.\nArticulata. \u2014 The animals composing this sub-kingdom are bilateral and symmetrical. The abstract pattern or type of an articulate animal, like that of the Vertebrata, is a symmetrical. figure.f From this primordial symmetry there are but few deviations, and those exceedingly trifling in amount.\nAmongst the Entozoa, the English tapeworm (Tcenia solium), if the flat sides be taken as dorsal and ventral, presents an instance of a-symmetry in the position of its genital orifices, which are situated on the edge of each joint, sometimes on one side, sometimes on the other, indifferently.\nIn the Natural History series of the Mu-\n* See fig. 409. Vol. III.\nf Vol. I. Fig. 378. art. Crustacea.\n3 i","page":849},{"file":"p0850.txt","language":"en","ocr_en":"850\nSYMMETRY.\nseum of the College of Surgeons (\"No. 205.), there is a portion of a t\u00e6nia lata, which exhibits a monstrosity very interesting in its bearing on the question of the individuality of half segments (p. 84-5.). On one side, which for distinction we will call right, there are three half segments, the middle one of which unites with two half segments of the left side, leaving the upper and lower of the three right halves isolated and independent. One of these contains a generative apparatus.\nMollusca. \u2014 In this sub-kingdom absence of symmetry seems to be the rule \u2014 its presence the exception. There are great practical difficulties in the way of finding an abstract notion or type of a mollusk such as have been found for the Vertebrata and Arti-culata. If, however, such type be symmetrical, that symmetry is departed from much oftener than it is preserved. There is no appearance in any mollusk of a serial repetition of parts \u2014 nothing like serial homology, except in the Chitons, whose shell consists of a number of similar symmetrical transverse bands. The highest class of mol-lusks, the Cephalopoda, are symmetrical, and when they inhabit shells, as the Argonaut and pearly Nautilus, their shells are symmetrical. But the enormous number of species comprised in the classes Gasteropoda and Acephala are nearly all unsymmetrical. The slugs are the most symmetrical of the Gasteropoda in their external form, but here the air-orifice, for instance, is on one side.\nRadiata. \u2014 For convenience of illustration, I select from among the animals composing this sub-kingdom the common star-fish. (Figs. 16, 22, &c. Vol. I. Art. Echinodermata.) This animal presents to our view a flattened form with five exactly similar rays or arms radiating from the centre, where is posited the mouth. Around the mouth is a nervous circle consisting of a number of ganglia corresponding to the arms, connected with each other by intercommunicating cords. Each arm is symmetrical in itself. Now this figure may be divided into two symmetrical halves by a line drawn across it in either of five different diameters. What is to decide which of these is to be regarded as the mesial line ? Fortunately there is, on the side which is the reverse to that on which the oral orifice is placed, a peculiar spot, the remains of an embryonic structure, which is not in the centre, and will therefore serve for a datum. In certain other echinoderms the anus is situated eccentrically, in which case it also may be taken as a datum. But still a line drawn through either of these, the number of the arms not being an even number, will divide one of them in its middle on one side, and pass through the interspace between two of them on the other. This, as the arms are exact repetitions of one another, seems an unnatural and arbitrary proceeding. Still, though it possesses no natural middle line, and consequently is not bilateral, yet is the star-fish a symmetrical animal, for the idea of bilateralism is by no means included in our definition of symmetry.\nWhenever a number of exactly similar parts symmetrical in themselves are arranged around a centre, whether their number be two, as in bilateral forms, or five, as in the star-fish, the whole figure is symmetrical. Abandoning then the idea of bilateralism, we may look upon the star-fish as composed of five repetitions arranged around a centre. Regarding it in this manner, we are able to institute a comparison between the form of the star-fish and that of the segmented vertebrates and articulates. The star-fish may be regarded as analogous to one segment of a vertebrate or articulate \u2014 an animal with one vertebra.\nI use the term \u201c analogous,\u201d and not \u201c homologous,\u201d because the relation called special homology cannot be demonstrated, in an}' instance, between animals belonging to different sub-kingdoms. The head, the legs, the brain of an articulate, are only functionally the head, legs, or brain. They perform the same function as, but they cannot be shown to be homologous with, the head, legs, or brain of a vertebrate. Indeed I have long held that the sub-kingdoms should be limited by reference to special homology : all animals among which homologies can be pointed out\u2014which all conform to the same type \u2014 should be grouped together to form a sub-kingdom.\nThe view of the analogy of a radiate animal to a vertebrate or articulate animal just given, is considerably strengthened by the manner of development of the common medusa. The larva of the medusa is a polypiform living thing, anchored by one end and tentaculated at the other. This, after a while, becomes marked with numerous constrictions, like a segmented animal, which constrictions become more and more deep until they completely divide the quondam polypiform being into a number of pieces, each of which becomes a perfect medusa. Here is a segmented animal, each of whose joints becomes an independent radiate individual; ergo, each individual is analogous to one segment of a vertebrate or articulate.\nTowards a different view tends the fact, that though five, or a multiple of five, is usually the number of the rays of the star-fish, yet there are some members of the same group the number of whose arms are neither the one nor the other; for instance, there are eleven and twelve-armed asterias. Now there is such perfect constancy in the number of the parts of vertebrate and articulate segments, that that constancy seems an integral element of the idea of an archetype. There is, however, no constancy in the number of the vertebrate or articulate segments that go to constitute an animal, and therefore some may regard each arm of an asteria as analogous to a vertebra ;\u2014 the common star-fish, as composed of five analogues of vertebral archetypes arranged in a circle, \u2014 as a segmented animal bent upon itself, with its anterior and posterior extremities adherent to one another. Which of these two views is the correct one \u2014 whether either is correct \u2014 can be decided then only when the true import of serial homology and of sym-","page":850},{"file":"p0851.txt","language":"en","ocr_en":"SYMMETRY\t851\nmetry is definitely ascertained ; when it is determined what is due to division, what to radiation, or whether division and radiation, one, or both, or neither, are concerned in their causation.\nThe skeleton of the Velella presents an instance of departure from symmetry, mainly in the oblique set of its vertical plate. The common medusa has a circular outline, and exhibits four quarters, which repeat one another exactly, so that it seems to be marked with a right-angled cross. The horizontal plate of the skeleton of Velella is distorted to a sub-rhomboid form, and marked with two diagonal seams that cross one another obliquely. The longer one of these diagonals is produced upwards so as to form the oblique sail-supporting vertical plate, which also presents a seam continued up from the point of crossing of the diagonals, indicating that it is composed of two parts uniting at this central point. This de facto unsymmetrical radiate is therefore easily reduced in idea to its primordial symmetry.\nInfusoria. \u2014 Out of the vast number of various forms met with amongst these animalcules the greater number are symmetrical. This symmetry is usually not bilateral, but that of the star-fish. There are, however, some forms which are quite irreconcilable with symmetry, which no line can divide into two similar halves, which are one, and present no repetitions of parts ; except, indeed, when they are undergoing fissiparous generation.\nAntero-posterior Symmetry. \u2014 By reference to the diagram at page 824. Vol. 111. Fig. 433., representing the abstract notion or type of a vertebral segment, it will be seen that the upper or posterior half is a reverse of the lower or anterior. Referring to what really exists in nature, we find, in the caudal vertebrae of fish, that their dorsal and ventral halves are counterparts tolerably' exact, yet that exactness is not nearly what exists between the lateral halves. If an anteroposterior as well as a lateral symmetry be admitted, then we have four repetitions arranged around a centre. At all events there is here, in the Vertebrata, some amount of evidence of radiation or divergence from a central axis comparable in some degree to what we see in the Radiata. The anterior and posterior parts of vertebral segments, as \u00ef found in nature, are usually extremely dissimilar. The rays of the dorsal and abdominal (anal) azygos fins of fishes are antero-posterior repetitions, but the fan-like tail fin, which in most fishes seems to be remarkably symmetrical antero-posteriorly, half of it apparently belonging to the dorsal and the other half to the abdominal moiety of the fish, usually belongs, as I have observed in the typical fishes, cyprinoid, &c., in reality, entirely to the abdominal or under moiety. The embryo of these fishes at first has a tail like an eel, into which the spinal column is continued nearly to its tip. A little way from the extremity of this, on the abdominal aspect, a group of\nfin rays are soon observed to sprout out meanwhile that the end of the vertebral column shrinks and turns up. The group of fin rays grows, and the vertebral column shrinks, so that in time the former is brought to form the fan-like extremity of the animal ; but even then the atrophied end of the vertebral column may be detected occupying the upper edge of the fan. Even in the adult fish some trace of this original relation of the tail fin can be detected. If the tail of an adult homocercal fish be macerated or boiled, and all the pieces which are not an-chylosed to it be removed, what remains will not be symmetrical, but will terminate by turning or cocking up. Even in the Pleuro-nectid\u00e6, whose tails seem to be remarkably symmetrical, and where the spinal column seems to terminate in a flat triangular piece, it will be found that the lower half of this piece can be easily removed, whilst the upper half forms one piece with the body of the last vertebra, with which, in fact, it forms a coccyx composed of numerous degenerated and consolidated vertebrae.\nSymmetry of Disease.\u2014This subject has been most ably treated by Dr. W. Budd #, of Bristol. Those local diseases, the cause of which is in the blood, usually affect the solids of the body symmetrically. This can be often well observed in lepra, psoriasis, secondary syphilis, gout, and rheumatism, and in the eruption caused by taking the iodide of potassium. It is due, no doubt, to the symmetrical disposition of those tissues for which the morbid poisons have a peculiar affinity. It proves, moreover, that there is more of peculiarity in certain parts of organs than what meets the eye, which peculiarity is symmetrical. For, though the tissue of all parts of a bone, for instance, shall be exactly the same, it shall be diseased at a certain part only, and the disease shall be repeated in exactly the same part of the corresponding bone of the opposite side. Connected with this is the observation made above, that the corresponding points of both sides of the body are exactly of the same age \u2014 have reached a certain stage of development at exactly the same time. But the force of this observation in explaining the symmetry of disease is considerably weakened by another fact noticed by Dr. W. Budd, namely, that the diseases above named are apt also to localise themselves in parts that are serially homologous, or corresponding in the upper or lower limbs, as the knee and elbow, wrist and ankle ; for these parts, though homologous, are not of the same age. It is well known that the development of the upper and lower limbs does not pro ceed pari passu. There is here, at least, some determining agency more mysterious than mere age. Still more curious and mysterious is the relation of the eruption called shingles to the bilateralism of the body'. It often extends zone-like around one half, stopping exactly at the median line before and behind,\n* Medico-Chirurgical Transactions for 1842.\n3 i 2","page":851},{"file":"p0852.txt","language":"en","ocr_en":"SYMPATHY.\n\u00ab52\nand thus seemingly affording evidence of that individuality of one half of the body which was spoken of as a feasible opinion above.\nPlants. \u2014 The leaf of the higher plants, \u2022\u201d\u2019hich is the unit or individual of botanists, is bilateral and symmetrical \u2014 always in idea, generally in fact. These leaves are associated together to form buds, branches, flowers, or fruits, in whorls. Symmetrical figures are often produced by these associations, but yet the pattern is spiral. In watching the development of spores of conferva, they are seen, whilst still but single cells, to shoot out in various manners, the majority of which are quite irreconcilable with symmetry, either bilateral or radiating. Whatever may be its import,* it is quite certain, from the very nature of symmetry, that the cause of it must be internal, that is to say, within the body in which it is manifested. But it has been conclusively determined, by experiments, that external influences, acting upon them in certain directions only, such as light, heat, and gravitation, exert a considerable power in determining the form of vegetable productions. Animals, doubtless, are also greatly affected by these agencies, yet, as they enjoy the faculty of locomotion whereby all parts of them are successively turned towards the directions from which these forces emanate, the form impressed upon them by internal causes, suffers little or no distortion therefrom; but plants, being destitute of locomotion, continually receive these influences in a partial manner, and consequently we the less expect to meet with symmetry among them. Whenever their internal forces tend to make them symmetrical, the partial action of external agents is apt to disturb their symmetry. It is this, probably, that renders the germinating conferva cell unsymmetrical.\nCrystals of unorganised matter are spoken of as symmetrical The symmetry, however, which they exhibit iis not a bilateral symmetry. It consists *of the repetition of the same angles and facets at the poles of an axis, but the repetitions are not reverses. The reader may illustrate my meaning by cutting a rhomboid in paper, when he will observe that each of its angles and sides are twice repeated, but he will find it impossible to fold it so that one half shall coincide with the other.\nThe precise import of the symmetry of organised bodies is, as repeatedly indicated above, as yet involved in mystery. Albeit a fact so evident, so constantly obvious to our senses, as often, like gravitation, to pass unheeded, it is a great and an important fact, \u2014 a fact of the same order with those which have already led to the establishment and demonstration of grand, comprehensive, and unassailable theories\u2014the bright triumphs of the human intellect, that have reduced to order, simplicity, and connexion, what before was all confused, complicated, and disjointed, \u2014 a fact, therefore, that inspires us with hope for our, as yet, imperfect science of anatomy. It seems to tell of radiant forces, of certain, definite, mathematical, and inexorable laws, concerned in the production of animals. Taken with\nthe other important fact \u2014 serial homology, it seems to suggest for the development of Vertebrata and Articulata the multiplication of centres in a serial line \u2014 of centres of radiant force, that then proceed to induce the surrounding particles to arrange themselves in a symmetrical figure. In truth, as the mind contemplates this fact, various theories pass before it, yet shadowy, changeable, and indistinct as a phantasmagoria. One day, perhaps, some one of these shall meet with definite enunciation and clear demonstration ; at present we must be content with putting the fact of symmetry prominently forward and exhibiting it in various points of view, with declaring it an important fact, and not a matter of course.\n(S. R. Pit tard.)\nSYMPATHETIC NERVE.\u2014(See Supplement.)\nSYMPATHY (<rvv-ira6os).\u2014 Sympathy may be defined as the assumption by different individuals, or by different parts of the same individual, of the same or an analogous physiological or pathological state at the same time, or in rapid succession. It is popularly known that the act of yawning, performed by one individual in a company, is apt to induce in many of the others an irresistible tendency to the same act. In a similar manner, the excitement of certain emotions (mirth or sadness, laughter or tears) is apt to spread through an assemblage of persons with extraordinary rapidity. The power of eloquence, of music, or of spectacle, to produce such effects,is witnessed every day in places of public resort, whether for devotion, business, or amusement.\nMany instances are known in which convulsions have been excited in persons not previously subject to them, by the sight of a patient in an epileptic fit. And peculiar nervous disorders, of a convulsive kind, have been found to affect nearly all the members of a community without the slightest evidence of their being contagious or infectious. An impression upon an organ of sense may produce effects very different in their nature to any thing which could be anticipated ; and these many be purely of a physical kind, or they may act primarily upon the mind. Thus certain odours will induce syncope in some people; and the smell of a savoury dish to a hungry person, or even the mention or the thought of a meal, will excite a flow of saliva. The emotion of pity excited by the sight of some object of compassion, or by a narrative of a mournful kind, will produce a copious flow of tears.\nAll such phenomena are said to result from Sympathy. When one yawns, immediately in consequence of another\u2019s yawning, the former evidently and truly sympathises with the latter ; and the convulsions which are induced by the sight of another in a fit, are not less sympathetic. The individual in whom the convulsions are induced, sympathises with the other. Such obvious instances of sympathy between different individuals led to*the","page":852},{"file":"p0853.txt","language":"en","ocr_en":"SYMPATHY.\n853\nsupposition of some such similar consent between different or even distant parts in the same person.\nMotions or sensations caused in certain parts, in consequence of a primary irritation of other and distant parts, are of the sympathetic kind. These motions or sensations are produced in, as it were, an indirect or circuitous manner, or one different from that in which they are ordinarily excited.\nThus a stimulus to the olfactory membrane causes a peculiar affection of the sense of smell, and occasions that depression of the heart\u2019s action, from which results a state of syncope. Or another affection of the same sense causes a suddenly increased action of the salivary glands.\nIf we analyse any one of these examples of sympathetic actions, it will appear that three circumstances may be noticed in the production of the phenomena : 1st, the primary exciting cause, which may be an object presented to the mind through one of the organs of sense, or causing an impression upon any sensitive nerve, and therefore upon some part of the centre of sensation; 2ndly, the part affected directly by this primary stimulus ; and, 3rdty, the action or sensation resulting from the affection of this part.\nMany other sensations or motions may be enumerated besides those above referred to, whether occurring in health or in disease; and we shall give examples of these before we discuss this subject further.\nThe examples of sympathetic sensations which may be adduced are chiefly of the morbid kind. Pain is felt at a certain part, in consequence of an irritation in another part distant from it, and apparently altogether unconnected with it. A familiar instance of this is pain in the knee from disease of the hip-joint. So marked in some instances is the pain in the knee, and so much has it absorbed the patient\u2019s attention, that the real seat of the disease has been overlooked, and the remedies been applied exclusively to the knee. Pain in the right shoulder, from disease of the liver, is a sympathetic sensation of similar kind; and sometimes the hepatic irritation causes pain over a more extensive surface. Whytt mentions, that, in two cases of suppuration of the liver, he had seen the patients \u201c affected wdth a numbness and debility of the right arm, thigh, and leg.\u201d Sometimes both shoulders are the seat of pain, from hepatic irritation.\nThe peculiar sensations felt in the teeth from a noise which grates upon the ears, is sympathetic of the irritation of the auditory nerve. Practitioners are well aware how many morbid sensations in parts remote from the intestinal canal may be cured by the removal of scybala or other accumulations from it. Painful affections of the nerves of the face, and of other parts, are often due to a cause of this kind. The irritation of a stone in the bladder gives rise to pains in the thighs, or to itching at the end of the penis ; and uterine irritation, whether from disease or\nfrom the enlargement of that organ in connection wdth the early stage of pregnancy, eauses similar pains in the nerves of the thighs.\nHeadache and defective vision are frequently produced by disordered stomach. A draught of very cold water, or ice, taken quickly into the stomach, may occasion acute pain in the course of either frontal nerve. This same nerve on one side is frequently the seat of pain after the imprudent use of acid wines or other fermented liquors.\nMovements, excited by the operation of a stimulus applied at a distance, form a large proportion of the instances of sympathetic phenomena. All the ordinary physical nervous actions in which motions are excited by stimulating a sentient surface, may be regarded as examples of sympathetic actions.* The contraction of the iris upon the application of the stimulus of light to the retina, or of the pharyngeal muscles by stimulating the mucous membrane of the fauces, are instances in point where the stimulus acts indirectly upon the contracting fibre. Nothing is more sure than that in these instances the change w'rought by the stimulus in certain sentient nerves, travels by a circuitous route through a nervous centre to the muscles which are called into action. Akin to these actions are the forcible respiratory movements which may be excited by irritation of the tracheal membrane, as coughing ; or sneezing, by stimulating the nasal membrane ; or vomiting, by irritating the fauces. Spasmodic affections are often instances of morbid actions in sympathy with intestinal irritation, or the irritation of teething in children. Partial or general convulsions are very frequently due to either or both these causes. We have known the most violent opisthotonos co-existing for a considerable time with the presence of lumbricoid ascarides in the intestine ; but ceasing immediately on the removal of the worms. Vomiting is commonly sympathetic of diseased kidney, or of the passage of a calculus along the ureter; or of the passage of a gall-stone along the gall duct ; or it may be induced by the introduction of a catheter into the urethra.\nThe consentaneous action of symmetrical parts is no doubt due to a similar cause to that by which most of the sympathetic actions are excited, and more especially in those parts where symmetry of action is constant, although liable to be interrupted by the influence of the will.\nA distinct class of sympathetic actions consists of those in which certain parts enlarge or become developed simultaneously with, and to a certain extent in effect of, the increase\n* It has been remarked, that the term \u201c sympathetic actions \u201d involves a contradiction. But it may be observed, that the contraction of the muscles, on which the action depends, is only the natural mode in which that class of vital organs can manifest their consent with certain states of nervous centres, or of sensitive nerves. The action is the result of the state which the muscle assumes in sympathy with the stimulated nerve. The contradiction is therefore apparent, not real.\n3 I 3","page":853},{"file":"p0854.txt","language":"en","ocr_en":"854\nSYMPATHY.\nof others. The penis, the beard, the vocal organs, experience a marked increase of development at the adult period of life simultaneously with the enlargement of the testes; and, it may be added, in effect of their increase, because the early removal of these organs prevents the growth of the others. And so likewise as the ovaria are developed, the uterus, the vulva, the mammae, increase in size ; the ovarian and uterine irritation which accompanies the menstrual flux causes enlargement of the breasts, which subsides as soon as that period has gone by.\nThe various examples enumerated in the preceding paragraphs may be classed under three heads : first, sympathies between different individuals ; secondly, those which affect the mind, and, through it, the body; and, thirdly, those which are strictly organic, and therefore physical.\nOf the first class of sympathies we can offer no physical explanation. Whether the nervous system of one individual can directly affect that of another, or whether the effect is produced on the imagination, and afterwards on the nervous system, are questions still stib judice. The serpent fascinates his prey, apparently by the power of his eyes, and it is well known that one man can exert a marked control over another by a mere look ; and in the same way man can control other animals, even the fiercest carnivora, by a firm and decided glance of the eyes. It is no explanation of sympathetic phenomena of this kind to ascribe them to the effect of a tendency to imitation. Imitation is voluntary ; these actions are involuntary, or take place even in despite of the will.*\nIn the second class of sympathetic phenomena, an affection of the mind is a necessary link. But why that affection of the mind should produce its peculiar effect is a question difficult to solve. Why should the perception of certain odours produce in one case increased action of the salivary glands, and in the other case cause syncope ? The only reply which can be made to this question is, that in these instances the impression on the senso-rium causes a change there analogous to that which an original affection of the mind of similar kind would produce, and therefore gives rise to effects of the same nature as those resulting from that mental change. Thus the smell of savoury food excites in the mind the idea of food, which in a hungry man would, if it occurred spontaneously, occasion a flow of saliva. And the odour which occasions syncope, creates in the mind an emotion of disgust, which, if it arose independently of the physical impression, would affect the heart through the centre of emotion. It is plain, however, that that portion of the nervous centre which is affected in such cases, must have a direct influence upon the parts in which the sympathetic phenomena appear; and this through commissural fibres, or the continuity of its gray matter with that of the centre from which its nerves immediately spring; thus, in the instances referred to, the * Bostock\u2019s Physiology, vol. iii. p. 227.\ncentre of sensation, which is first affected, is, through the medulla oblongata, connected with the salivary glands by the fifth nerve, and with the heart by the vagus.\nWe derive an explanation of the third class of sympathetic phenomena from the known laws of sensitive and motor nerves. It is known that stimulation of a sensitive nerve at its origin, or in any part of its course, will give rise to a sensation which will be referred to the peripheral extremity of the stimulated fibres ; and that a stimulus applied to a motor nerve causes a change in it which spreads peripherad from the point stimulated, and therefore affects the muscular parts with which it is connected. It is known also, that a sentient nerve may excite a motor or sensitive nerve which is implanted near to it in the nervous centre \u2014 doubtless through the change which it produces in that centre ; nor can it be doubted that a sensitive nerve may receive such a powerful stimulus as to exalt the polar force of a large portion of the nervous centre in the neighbourhood of its insertion, and thus to excite a similar change in all the nerves, whether motor or sensitive, which are connected with it. Thus, according to the intensity of the original stimulus, there will be a radiation of nervous force from the centre, either in one or two motor or sensitive nerves, or in several such ; and the number and variety of the sympathetic phenomena will thus depend on the intensity and extent of the change in the nervous centre excited by the primary stimulus.\nTo explain, then, the phenomena of sensation and motion under consideration, we must determine the individual nerves affected in each instance, and ascertain what connexions they have with each other. We learn from anatomical investigation, that, although nerves anastomose with each other in their distribution, this anastomosis is by no means of that kind which would justify the supposition that an irritation could be communicated from one to the other in their course. The nerve-fibres only lie in juxtaposition, but do not communicate ; and there is an evident provision in the tubular membrane and white substance of Schwann for the insulation of the central axis, which is probably the effective substance in the nervous action. We must seek, therefore, in the nervous centres for such a communication between these nerves as may explain the excitability of one by the other. In the present state of our knowledge we can do no more than state it as in the highest degree probable that nerves implanted in the centre immediately contiguous to each other can exert an influence upon the vesicular matter of the centre, and upon each other.\nBut there are certain facts which demonstrate beyond all doubt, that, in such actions as we refer to, the integrity of the centre forms a necessary condition. First, in many of the instances it is plain that there can be no connexion between the affected nerves elsewhere than in the centre, for they are so distinct from each other that there is not even","page":854},{"file":"p0855.txt","language":"en","ocr_en":"SYMPATHY.\t8 55\nthat apparent connexion which results from the anastomosis of a fasciculus of fibres of the one with a portion of the other. Secondly, the removal of the portion of the nervous centre with which any one of the nerves concerned in the sympathetic action is connected, will prevent the development of the phenomenon, although the nerves themselves remain uninjured in their peripheral distribution, or in their connexion with each other. Thirdly, if there were any peripheral communication between nerves, it would be most likely to take place in the plexuses. Experiments, however, upon the nerves which lead to these show that each nerve-tube, in its passage through them, retains its isolation as distinctly as in any other part of its course. The three nerves which supply the lower extremity in the frog, says Miiller, form a plexus from which two nervous trunks issue t if one of these latter be divided and isolated from all its connexions with muscles, and the portion of it connected with the plexus irritated, the impression will be transmitted in the centripetal direction by the sensitive fibres of nerve; but the motor fibres of the other nerve arising from the plexus are not affected, and excite no contractions in the muscles to which they are distributed.*\nIn applying these principles to the explanation of the instances which we have quoted, we shall find it difficult to determine the central connexion in some, although in others such a connexion is highly probable. Jt remains, therefore, for future anatomical research to ascertain what that connexion is which enables one nerve to sympathise with another. In the instance of pain in the shoulder in sympathy with irritation of the liver, the hepatic irritation excites a change in some sensitive nerves, which is propagated to the centre, and there affects some of the sentient fibres distributed in the region of the shoulder. The phrenic and the external thoracic nerves are both or either of them, but more especially the former, favourably situated to constitute the excitant of such a sympathetic sensation. The phrenic nerve of the right side is largely distributed upon the peritoneal surface of the diaphragm, and upon the inferior vena cava, and forms many connexions with the hepatic plexus in the substance of the liver. It may therefore readily participate in any irritation of that organ. Now, the phrenic nerve is implanted in the spinal cord on a level with the third or fourth cervical nerves ; and the nerves of the shoulder form their connexion with this central organ about the same level.. The origins of these nerves, therefore, are sufficiently contiguous to each other to warrant the belief that an irritated state of one may be propagated to the other through the vesicular matter of the centre. But it may be inquired why the irritation is limited to sensitive nerves of the shoulder ; and why movements are not excited by the stimulation of the motor fibres of the phrenic itself, or of other * Baly\u2019s Muller, voL i. p. 756.\nnerves. The limitation of the irritation to one or two nerves depends on the degree of the stimulus, and the absence of any movements is due to the disposition of the phrenic nerve on the surface being unfavourable for the excitation of motions by irritation of its peripheral branches. And the experiment cited from Miiller, in the last paragraph, shows that simple irritation of the trunk of a compound nerve in connexion with the centre is not sufficient to produce motion ; which requires probably either a more prolonged and violent irritation of the nerve, or a polar state of the centre in which it is implanted.\nSome of the instances of sympathetic sensations, referred to above, do not admit of an explanation so obvious. The pain over the brow from ice or cold water in the stomach may be referred to irritation of the gastric branches of the vagus, communicated in the medulla oblongata to the fifth ; but why the irritation should be limited to the ophthalmic division of the fifth cannot be accounted for in the present state of our knowledge.\nIn those sympathetic movements which are of ordinary and normal occurrence, two provisions seem to be secured, namely, a certain peripheral organisation of the excitor nerve, and a certain central relation between it and the motor nerve. But in those which are of a morbid kind, it is necessary to suppose the existence of a more or less exalted polarity of the centre in order to explain the phenomena fully. This polar state will continue in many instances even after the primary peripheral irritation has been removed, as in tetanus, or in the convulsions from intestinal irritation ; and we learn from this fact the importance in practice of attending to the state of the nervous centre, as well as to the removal of the irritating cause.\nThere are other sympathetic phenomena, of the physical kind, in. which, however, the nervous system does not appear to take a prominent part. Such are the changes which occur in different and distant organs in connexion with a particular period of life, or the development of a particular function. Among these are the phenomena of puberty in both sexes ; the enlargement of the mammae in pregnancy. Whatever part the nervous system may take in such changes, it is impossible to account for them by reference to that system only ; they must rather be regarded as phenomena of nutrition occurring in harmony with the laws of growth, and therefore affecting the vital fluid more particularly than any part of the system of solid parts.\nContinuity of texture disposes, as is well known, to the extension of a diseased state originating at some one point. So also does contiguity. Phlegmonous inflammation of the areolar tissue, and erysipelas in the skin, spread with great rapidity. Inflammation arising in one of the opposed surfaces of a, serous membrane readily attacks the other. These effects have been vaguely assigned to sympathy (the continuous and contiguous sympathy of Hunter). But it cannot be supposed\n3 i 4","page":855},{"file":"p0856.txt","language":"en","ocr_en":"856\nTASTE.\nthat the nervous system takes part in the production of such phenomena, which ought rather to be ascribed, in the one case, to the continuity of blood-vessels, and, in the other, to contamination either by effused fluids or by morbid blood.\t(R. B. Todd.)\nSYNOVIA is that fluid which exists within the membrane lining joints, to assist motion by lubrication ; as also in the bursae. The membranes generally, which line the various cavities of the body, are lubricated by fluid. This varies in character according to circumstances ; and among these perhaps none more tend to the requirement of especial conditions than that of active and frequent motion, involving friction of the surfaces so lubricated.\nThus we find that the fluid of the pericardium differs essentially from that of the ventricles of the brain ; while again the synovia, supplying moisture to the joints, varies greatly from the fluid of the pericardium, probably in order to assist the opposed surfaces in bearing friction in an exaggerated degree. The word attrition appears, indeed, the most appropriate to the conditions relieved by the presence of synovia, placed as it is between surfaces occasionally strongly approximated either by superincumbent weight or muscular contraction.\nSynovia was chemically examined by Margueron.* The specimen he analysed was viscid, and became gelatinous soon after it was obtained. It then deposited a fibrous matter, and became clear above. Though the analysis of Margueron was not conducted on the more exact principles characterising those of the present dayr, it still serves to show that the specimen was peculiar as an animal fluid, and differed in one respect from the fluids generally, which lubricate surfaces. Thus it appears that as much as 1186 per cent, was composed of fibrinous matter (fibrin), which coagulated, as stated before, soon after the fluid was obtained.\nMargueron\u2019s analysis is as follows: \u2014\nFibrin\t-\t-\t-\t-\t11-86\nAlbumen\t-\t-\t-\t4\u201852\nChloride of Sodium\t-\t-\t1*75\nSoda\t-\t-\t-\t-\t071\nPhosphate of Lime\t-\t-\t0*70\nWater -\t80*46\n100-\nSynovia has of late years been examined by John.f It is described as a viscid transparent yellowish or reddish fluid, resembling in its odour the serum of the blood. The analysis\nis stated as follows : \u2014\nWater ----- 92*80 Albumen -----\t6*40\nExtractive Matter, Chloride of Sodium, and Carbonate of Soda -----\t0-60\nPhosphate of Lime -\t-\t0*15\n* Ann. de Chimie, xiv.\nt Simon\u2019s Animal Chemistry. Trans. Sydenham Society.\nIt will be seen that these two analyses vary greatly\u2014they were not made, it must be recollected,at the same date; and the methods of animal analysis are greatly improved since Margueron published. There is, however, an important point in which both analyses agree, viz. in stating phosphate of lime among the constituents of the fluid. John makes no mention of the existence of a coagulable fibrinous matter ; a fact of much importance, which it appears desirable carefully to inquire into, insomuch as it is very possible the analyst may have extracted the synovia after coagulation had occurred within the membrane, and so obtained the clear fluid only ; while Margueron may have been fortunate enough to secure it before such change had taken place, and in its natural condition.\nWith regard to this subject, on which our knowledge is but scanty, it appears still of importance to reflect on the material before us ; and it is matter of no small interest to consider how far the results of peculiar mechanical conditions are modified by variations in the character of lubricating fluids, knowing, as we do, that, while the ventricles of the brain, subject to agitation only, contain no albumen in their lubricating fluid, the liquor of the pericardium contains that principle in abundance ; and that in the synovial fluid adapted to the lubrication of the joints, we have, in addition to albumen, not only a considerable proportion of phosphate of lime, but probably fibrin also, as a necessary constituent.\t(G. Owen Rees.)\nTASTE.\u2014 The sense by which we distinguish the sapid properties of bodies. The term, as commonly understood, includes much more than this ; being usually employed to designate the whole of that knowledge of the qualities of a body (except such as is purely tactile), which we derive through the sensory apparatus situated within the mouth. But it will be hereafter shown tnat a considerable part of this is dependent upon the assistance of the olfactive sense ; which is affected, through the posterior nares, by the odorous emanations of all such bodies as are capable of giving them off ; and the indications of which are so combined with those of the true gustative sense, as to make an apparently single impression upon the sensorium. Moreover, there are certain sensorial impressions received through the organ of taste, which are so nearly allied in their character to those of touch, as to render it difficult to specify any fundamental difference between them : such are the pungent sensations produced by mustard, pepper, the essential oils, &c. ; all of which substances produce a sensation when applied for a sufficient length of time to any part of the cutaneous surface, which can scarcely be distinguished from that excited through the organ of taste, in any other way than by its inferior intensity, and by the absence of the concurrent odorous emanations. The taste of such substances might, perhaps, be considered, therefore, as the composite re-","page":856},{"file":"p0857.txt","language":"en","ocr_en":"TASTE.\n857\nsuit of the impressions made upon the senso-rium through a refined and acute touch, and by the effect of their odorous emanations upon the organ of smell. After making full allowance, however, for all such as can be thus accounted for, there remains a large class of pure sapors, of which we take cognizance without the assistance of smell, and which are altogether dissimilar to any tactile impressions : such are the bitter of quinine, the sour of tartaric acid, the sweet of sugar, the saline of common salt, &c. The smell can give us no assistance in distinguishing small particles of these bodies, since they are either entirely inodorous, or so nearly so as only to be recognizable through its means when in large masses ; and the most refined touch cannot afford any indication of that kind of difference among them, of which we are at once rendered cognizant by taste. Still the gustative sensations scarcely differ more from the tactile than some of these last differ among each other,\u2014 the sense of heat and cold, for example, from the simple sense of contact or resistance ; and we shall find that the analogy between these two senses is so strong, both as to the conditions under which they are respectively exercised, and the structure of the apparatus through which the impressions are received, that they must be regarded as much more nearly related to each other than either of them is to the other senses, or than the latter are amongst themselves.\nThe seat of the sense of taste is always at the entrance to the alimentary canal ; and its purpose is obviously to afford a means of discrimination among the substances introduced into the mouth as food. The surface of the tongue is undoubtedly the special organ of taste in the higher animals ; but there is adequate evidence that the sense is not entirely restricted to that organ, even in man ; and it would seem improbable, considering the obvious purpose of the sense, that it should be wanting in that very large proportion of the animal kingdom in which no tongue exists, or in which the surface of that organ is so hard and horny as to forbid our attributing to it the possession of gustative sensibility. Without affirming (with Magendie) that the specific gustative sensibility extends over the teeth, the gums, the palate, and the pharynx, we feel justified in stating that in most persons it is distinctly present on the surface of the soft palate, especially in the neighbourhood of the uvula, and on that of the arches of the palate and of the fauces; and in a less degree on the surface of the anterior part of the soft palate. In making experiments upon this point, as well as upon many others connected with the sense of taste, it is important to bear in mind that if aromatic substances be employed, the impressions derived through the sense of smell may confuse the result; and also that if the sensory surface be too much exposed to cold air, its sensibility will be greatly diminished. Further, it should be borne in mind that a considerable amount of individuil difference may not improbably\nexist, both as to the extent of the gustative surface, and the relative acuteness of the sense in different parts.\nConditions of the Sense of Taste. \u2014 In order that gustative impressions may be communicated to the sensorium, the first requisite is an afferent nerve, endowed with the power of receiving and transmitting them. The gustative surface in man and the higher animals being supplied by two afferent nerves, \u2014 the glosso-pharyngeal, and the lingual branch of the fifth pair,\u2014 w'e shall have to inquire whether both of these are subservient to the sense of taste, as well as to that of touch ; or whether, as in the case of the organs of smell, sight, and hearing, there is one nerve of special and another of general sense. The peripheral extremities of both these nerves are in relation with a papillary apparatus, in which they are elevated above the general surface, and come into close proximity with capillary loops ; and here, as elsewhere, it appears certain that the neighbourhood of circulating blood is an essential condition for the reception of sensory impressions. For the gustative nerve-fibres to be impressed by the distinctive properties of sapid substances, it would further seem requisite that these substances should be brought into immediate relation with them, and that they should penetrate, in the state of solution, through the investments of the papillae, into their substance. This would seem to be proved by the two following facts : first, that every substance which possesses a distinct taste is more or less soluble in the fluids of the mouth, whilst substances which are perfectly insoluble do not make their presence known in any other way than through the sense of touch ; and, second, that if the most sapid substance be applied in a dry state to the papillary surface, and this be also dry, no sensation of taste is excited. Hence it may be inferred that, in the reception of gustative impressions, a change is produced in the molecular condition of the nerve-fibres, or, to use the language of Messrs. Todd and Bowman, their polarity is excited, by the direct agency of the sapid matter itself. This change may be induced, however, both by electrical and mechanical stimulation. If we make the tongue form part of a galvanic circuit, a peculiar sensation is excited, which is certainly allied rather to the gustative than to the tactile, and which does not seem to be due (as at one time supposed) to the decomposition of the salts of the saliva. And, as Dr. Baly has pointed out*, \u201cif the end of the finger be made to strike quickly, but lightly, the surface of the tongue at its tip, or its edge near the tip, so as to affect not the substance of the organ, but merely the papillae, a taste sometimes acid, sometimes saline, like the taste produced by electricity, will be distinctly perceived. The sensation of taste thus induced will sometimes continue several seconds after the application of the mechanical stimulus.\u201d\n* Translation of Miiller\u2019s Physiology, p. 1062, note.","page":857},{"file":"p0858.txt","language":"en","ocr_en":"858\nTASTE.\nOn the other hand, as Wagner has truly remarked, if the surface of the tongue near the root be touched with a clean dry glass rod, or a drop of distilled water be placed upon it, a slightly bitterish sensation is produced ; and this, if the pressure be continued, passes into that of nausea, and if the pressure be increased even excites vomiting. The feeling of nausea may be excited by mechanical irritation of any part of the surface of the fauces and soft palate ; and this feeling is certainly much more allied to that of taste than to that of touch. Further, it has been observed by Henle, that if a small current of air be directed upon the tongue, it gives rise to a cool saline taste like that of saltpetre. Thus we find that the peculiar effects of sapid substances upon the nerves of taste may be imitated to a certain extent by other agencies : and it also appears that the sensations excited by these vary according to the part of the gustative surface on which they operate ; mechanical or electrical stimulation of the front of the tongue giving rise to a kind of saline taste, whilst mechanical stimulation applied to the back of the tongue and fauces excites the feelings of bitterness and nausea.\nOne of the conditions requisite for the due exercise of the gustative sense, is a temperature not departing far on either side from that which is natural to the body. It appears from the recent experiments of Prof. E. H. Weber *, that if the tongue be kept immersed for nearly a minute in water of about 125\u00b0, the taste of sugar brought in contact with it, either in powder or solution, is no longer perceived ; the sense of touch, usually so delicate at the tip of the tongue, being also rendered imperfect. A similar imperfection of taste and touch was produced by immersing the tongue for the same length of time in a mixture of water and broken ice.\nNerves of Taste. \u2014 Much controversy has taken place upon the question whether or not there be a special nerve of taste ; and whether the lingual branch of the fifth pair, or the glosso-pharyngeal, possesses the best claim to this title. The principal points of this controversy have been already noticed [See Fifth Pair and Glosso-Pharyngeal] ; a short review of it, however, with a notice of the most recent inquiries on the subject, will be here desirable. That the glosso-pharyngeal is the special nerve of taste, and that its complete section on both sides destroys the sensibility to gustative impressions, was first affirmed by Panizza ; and his conclusions, adopted by Dr. M. Hall and Mr. Broughton f, have been since, to a certain extent, supported by the experiments of Valentin \u00a3 and Bruns.$ The grounds on which this doctrine rests are briefly as follows:\u2014After re-\n* M\u00fcllers Archiv. 1847, S. 342. _\nj\" Sixth Report of British Association; p. 125 of Transactions of Sections.\n+ De Functionibus Nervorum Cerebralium,- &c., 1849, p. 41.\n\u00a7 l)e Nervis Cetaceorum, Tub. 1836 ; quoted by\nM\u00fcller.\ncovering from the depression which is the immediate consequence of the operation, a dog whose glosso-pharyngeal nerves have been divided is said to eat pieces of meat rendered bitter with colocynth, and to drink milk and water dosed with the same drug, without any repugnance j whereas if the lingual nerves be divided and the glosso-pharyngeals left entire, the bitter morsel is rejected as soon as it reaches the back of the mouth, although it may have been at first seized very hastily. But, on the contrary, it has been affirmed by Kornfeld * * \u00a7, with whom MUller and Gurlt were associated, by Dr. Alcockf, by Dr. John Reid J, by Guyot and Cazalis \u00ff, by Magendie U, by Longet^T, and by Volkmann and Bidder**, that distinct indications may be obtained of the persistence of the sense of taste, after complete section of the glossopharyngeal nerves on both sides. Of a dog in which the nerve had been divided before giving off' a single filament, Dr. J. Reid states : \u2014 \u201cI have repeatedly fed that dog with morsels of animal food from my hand ; and after he had taken several morsels in this way, which he readily swallowed, I then presented a morsel similar in size to the others, and with the colocynth, concealed in a way that he could not see it ; but no sooner was it taken into the mouth than it was rejected with evident symptoms of disgust. This was repeated more than once.\u201d Bidder found that although two dogs whose glosso-pharyn-gei had been divided, swallowed pieces of flesh soaked in an infusion of colocynth, which another dog whose nerves were uninjured at once rejected, yet certain movements of the lips and tongue were observed, which showed that these were not altogether relished. It is obvious that, in such an inquiry, positive evidence of the continuance of the sense of taste is more conclusive than the negative evidence from which its absence may be inferred. It is right to bear in mind that, as Wagner has pointed out, dogs when they are hungry will devour meat however strongly seasoned with bitter drugs, though all their nerves be entire. Dr. Reid makes the remark, in explanation of the results of Panizza, that one of the dogs on which he had divided the glosso-pharyngeal nerves, would eat the morsel of meat containing colocynth, rather than lose it, when very hungry ; though he refused it, if he saw any prospect of procuring another free from the bitter. Wherever any such evidence of the persistence of the sense of taste was obtained, this appeared specially to exist in the anterior portion of the mouth.\n* De Functionibus Nervorum Lingu\u00e6 Exp\u00e9rimenta. Berol. 1836.\nf Dublin Journal of Medical and Chemical Science, 1836.\nt Edinb. Med. and Surg. Journal, Jan. 1838.\n\u00a7 Archives Generales de M\u00e9decine, 1839.\nIl Le\u00e7ons sur les Fonctions du. Syst\u00e8me Nerveux, 1839, torn. ii.\n\u00ab|[ Anatomie et Physiologie du Syst\u00e8me Nerveux, 1842, torn. ii. p. 225.\n** Articles JVervenphi/siolo<jie and Schmecken in Wagner\u2019s Handw\u00f6rterbuch der Physiologie.","page":858},{"file":"p0859.txt","language":"en","ocr_en":"TASTE.\n859\nOn the other hand, it has been maintained by some physiologists (especially Magendie, M\u00fcller, Gur It, and Kornfeld), that the lingual branch of the fifth pair is the special nerve of taste ; although Muller does not altogether exclude the participation of the glosso-pha-ryngeal as having a share in the transmission of gustative impressions from the posterior part of the tongue and the fauces. The experiments of Dr. Alcock and others, however, appear to show that very distinct indications of gustative sensibility are presented by animals in which this nerve has been divided, the sense being merely deficient in the anterior part of the tongue.\nOn the whole, then, it may be concluded from experiment, that the glosso-pharyngeal nerve and the lingual branch of the fifth pair minister alike to the sense of taste ; the former being concerned in the transmission of gustative impressions from the fauces and the posterior part of the tongue, and the latter from the anterior portion of the tongue ; and the former being the special recipient of the impressions which produce the sense of nausea. This inference is so completely in harmony with the results of anatomical inquiry, that it may be considered as having a very strong claim to reception as a physiological truth. The branches of the glosso-pharyngeal appear to constitute the sole nervous supply of that region at the base of the tongue, of which the circumvallate papillae form the centre, and also of the sides of the tongue near the base. As it is universally admitted that these parts are acutely endowed with gustative sensibility, we cannot help regarding the glosso-pharyngeal nerve as its instrument. On the other hand, the middle and anterior parts of the dorsum of the tongue appear to be solely supplied from the fifth pair, \u2014the tip, however, receiving a branch from the glosso-pharyngeal, which runs towards it, along the under surface. It has been denied by some physiologists that the central portion of the upper surface possesses the proper gustative sensibility ; but we fully coincide in the statements of those who maintain the affirmative : and although it must be admitted that the sense is not so acute as it is at the base, sides, and apex of the tongue ; yet this may be fairly attributed to the greater thickness of the epithelial investment, and to the predominance of the conical papillae over the fungiform in the central region.\nOn turning to the pathological evidence which bears upon this question, we find an apparent contradiction in the phenomena recorded by different observers ; but this is in a great degree removed by a more careful examination ; and the evidence on the whole preponderates in favour of the preceding conclusions. We shall make use of the excellent summary recently put forth by Dr. J. Reid * : \u2014 \u201c In the single cases observed and recorded by Mayo, Serres, Romberg, Mr. Bishop, and Todd and Bowman, and in the two cases by * Physiological, Pathological, and Anatomical Researches, p. 268.\nMr. Dixon, both common sensation and the sense of taste were annihilated in those parts of the tongue supplied by the fifth pair ; while in one case related by Mr. Noble, and another by Vogt, common sensation was lost in the parts of the tongue supplied by the third branch of the fifth pair, yet the sense of taste remained in these parts ; and in a second case related by Mr. Noble, there was loss of taste with maintenance of feeling.\u201d In some of these cases the loss of the sense of taste appeared to extend to the base of the tongue ; but there was evidence that in these the glosso-pharyngeal nerve was also involved in the paralysis. \u201c We have no proof,\u201d continues Dr. Reid, \u201c that in the cases related by Mr. Noble and Vogt, the whole of the filaments of the fifth pair sent to the tongue were affected ; and in the case of Vogt the derangement of the nerve was only temporary, for the patient recovered the sensation of the part paralysed after the end of six weeks. We believe that these cases, when examined more closely, will rather be regarded as affording arguments in favour of the opinion, that the same nervous filaments do not convey inwards the impressions which excite pain and touch and the impressions which excite taste ; and that different filaments for conveying inwards the impressions that excite these sensations are bound up in the lingual branch of the fifth pair.\u201d There is believed to be no case on record, in which the whole of the fifth pair, or of the third branch of it, was found to be diseased after death, and in which, during life, the sense of taste had been retained in the anterior and middle parts of the tongue. The evidence of pathology, therefore, is in favour of that conclusion, as to the participation of the fifth pair with the glosso-pharyngeal in the sense of taste, at which we had arrived on other grounds.\nThe question still remains, however, as to the speciality of the nervous fibres which convey the gustative impressions ; that is, whether they are the common sensory fibres, whose peculiarity of function depends on the nature of the papillary apparatus at their peripheral origin; or whether they are incapable, like the fibres of the olfactive, optic, and auditory nerves, of conveying impressions of the ordinary sensorial kind, being adapted exclusively to receive and transmit the peculiar impressions made by sapid bodies. Now, in favour of the first view, it may be urged, that the conditions of the sense of taste are so nearly allied to those required for the exercise of touch, that the two can scarcely be distinguished on this ground, and that the fifth pair and the glosso-pharyngeal are both nerves of common as well as of gustative sensibility ; neither of which can be affirmed in regard to the three other senses, or of the nerves which minister to them. But, on the other hand, it must be remarked, that these nerves do not seem to be endowed with gustative and common sensibility in equal proportions ; for the glosso-pharyngeal, which is decidedly more","page":859},{"file":"p0860.txt","language":"en","ocr_en":"860\tTASTE,\nsusceptible than the lingual to gustative impressions, far less readily excites manifestations of pain when subjected to mechanical irritation. Hence, it would seem not improbable, that there may be in each a mixture of the fibres which minister to the sense of taste with those of tactile sensibility ; and that the former may be so far special in their endowments, as to be capable of receiving only the peculiar impressions made by sapid bodies, to which the latter may be insensible. Such a view would seem to be supported by the cases of Vogt and Noble just referred to ; and it is in harmony with the views to which we are led from the consideration of the diversities manifested between the sense of heat and cold and that of simple contact. [See Touch.]\nGustative Papill\u00e6.\u2014The tongue is copiously furnished with a papillary structure, bearing a close resemblance to that of the skin, but in many respects more complicated. Referring to the article Tongue for a more particular anatomical description of these papillae, we have now to inquire into their connexion with the sense of taste. According to the recent investigations of Messrs. Todd and Bowman, the lingual papillae are either simple or compound ; the former, which do not differ from those of the cutaneous surface in any other obvious character than the nature of their epithelial investment, are scattered over the whole surface of the tongue, in parts where the others do not exist, but they also participate in the formation of the compound papillae ; the latter are of three kinds, the cir-cuvivallate or cali/ciform, the fungiform, and the conical.\u2014The circumvallatc papillae, which are only eight or ten in number, and are restricted to a small space at the base of the tongue, consist merely of groups of simple papillae, arranged in a peculiar manner, and separated from those of the adjacent mucous membrane by a circular fissure. Into these simple papillae it has not yet been found possible to trace any distinct nerve-fibres, though there can be little doubt that it is penetrated by at least the essential part of them.\u2014The fungiform papillae are scattered singly over the surface, chiefly about the sides and apex, and but very sparingly in the middle of the dorsal region, though they are abundant in front of the cir-cumvallate papillae. These are composed of aggregations of simple papillae, which rise, however, considerably above the surface, and are covered with an epithelium so thin that they are distinguished by their blood-red colour. Fasciculi of nerve-tubes may be distinctly traced into them ; but of the nature of their termination it would be unwise to give a positive statement. Some of the appearances presented by them favour the idea that they form loops at their peripheral extremities ; whilst, in other instances, the tubular portion of the fibre, with the white substance of Schwann, seems to terminate somewhat abruptly, whilst the central axis is continued onwards into the substance of the enveloping t:ssue, in which it loses itself.\n\u2014The conical or filiform, which are the most numerous of the compound papillae, are diffused over the whole surface of the tongue, though most largely and numerously developed in its central part. They consist of clusters of simple papillae of a peculiarly elongated form, containing tubular nerve-fibres, which may frequently be seen to form distinct loops in their interior; but their chief peculiarity consists in their epithelial investment, which forms about two-thirds of their length, and gives to them their whitish tint. This investment consists of a tuft of long pointed processes, some of which present a near approach in their dense texture to hair ; whilst others may be regarded as soft or uncondensed hairs. These processes are sent off from the sides and summits of the secondary papillae, and are usually inclined backwards, lying buried in the recesses of the mouth. The foregoing description applies, however, only to the conical papillae of the human tongue ; and there is a considerable diversity in their structure in other animals. Thus, in the Ruminants, each conical papilla is terminated by a long, slender, flexible, horny filament, curving backwards ; and in the Felines some of them are furnished with a brushlike tuft of slender horny filaments, like those of man*, whilst others are encased by firm horny sheaths, which are prolonged backwards as stiff' spines. It is to this arrangement that the peculiar roughness of the tongue of the cat is due ; the organ being thus enabled to act as a flexible rasp, whereby the bones which they lick may be effectually cleaned of the smallest particles of flesh that may adhere to them ; and a single stroke of the tongue of a lion is said to be capable of abrading the whole thickness of the human skin.\nAfter what has been already said of the conditions essential to the exercise of the sense of taste, there is no occasion to do more than point out the evident fact, that, if some of the papill\u00e6 be covered with an epithelial investment so dense as to resemble horn, and offering an effectual barrier to the penetration of fluids, these cannot be supposed to have much participation in the sense, if they possess any. It is obvious that in the Felines the function of the spiny papill\u00e6 must be purely mechanical ; and it seems probable that the brush-like papill\u00e6 which lie among them, in common with those of man, possess simple tactile sensibility, serving to direct those muscular actions of the organ, which so remarkably adapt it to deal with minute particles of food. On the other hand, the thinness of the epithelial investment on the simple papill\u00e6 which are scattered over the surface of the tongue, and which form the circumvallate and fungiform papill\u00e6 by their aggregation, indicates their special adaptation to receive gustative impressions ; and this must be admitted to be more especially the case with the fungiform papill\u00e6, which often\n* By Cuvier these filaments are supposed to be the ultimate fasciculi of the fibres of the gustative nerve ; but this is certainly an error.","page":860},{"file":"p0861.txt","language":"en","ocr_en":"TASTE.\n861\nundergo a kind of erection when sapid substances are brought into contact with them. This inference is in complete harmony with the relative acuteness of the senses of taste and touch, in the portions of the surface on which the one or the other class of papillae is most abundant ; thus the sides and back part of the tongue are unquestionably the parts where the gustative sensibility is the greatest, and it is there that the fungiform, circumvallate, and simple papillae are most thickly set; whilst the apex and central part of the dorsum, over which the tactile sensibility is predominant, is that on which we meet with the largest number of filiform papillae. Whether there be any difference among the simple isolated papillae, and among those which are aggregated into the composite bodies that are termed fungiform and circumvallate, we are scarcely in a condition even to form a guess, until it shall have been determined whether the gustative and tactile nerve-fibres are identical or diverse in their endowments. If the former, it will be reasonable to suppose that every papilla through which a gustative impression can be made in virtue of the penetration of sapid matter into its tissue, may also be subservient to the reception of tactile impressions from mechanical stimulation. On the other hand, if it should be proved that the gustative sense depends on a special set of fibres, we should still have to inquire whether the same papilla may not contain fibres of both classes, so as to minister to both functions ; or whether some of the papill\u00e6 are purely gustative, whilst others are purely tactile.\nAt present there is no adequate reason to suppose that there is any essential difference of function among the papill\u00e6 covered with a soft thin epithelium, whether these be solitary or aggregate. An attempt was made by Horn * to establish some such diversity ; but the results of his experiments would rather lead to the supposition that there is a difference in the gustative sensations excited by the same substance, according as it is applied to different regions of the tongue, than to different papill\u00e6. Thus he found that more than three-fourths of the substances which he applied to the circumvallate papill\u00e6 excited a bitter taste, or one in which a bitter was associated with some other flavour, especially an alkaline or saline ; whilst the majority of the substances applied to the filiform papill\u00e6 tasted acid, or acid with a mixture of bitter and sweet. But since, as we have seen, mere mechanical stimulation produces different gustative sensations according to the part of the tongue to which it is applied, it is probable that the difference in Horn\u2019s results is not to be set down to the account of the papill\u00e6, but rather to that of the nerves by which they are respectively supplied.\nExercise of the Sense.\u2014 The simple application of a sapid substance to the gustative surface is usually sufficient to excite the sen-\n* Ueber den Geschmacksinn des Menschen. Heidelberg, 1825.\nsation ; and if this application be restricted to one particular spot, we are able to recognise its place more or less distinctly. In this respect, then, the gustative impression resembles the tactile ; for whilst we cannot, by our own consciousness, distinguish the parts of the retina or of the auditory apparatus on which visual or auditory impressions are made, we can make this distinction in regard to the surface which is supplied by the nerves of general sense. This determination is most precise when the impression is made on the parts of the tongue of which the gustative sensibility is most acute ; namely, the apex, sides, and posterior part of the dorsum; being probably aided, however, near the tip, by the acuteness of its tactile sensibility. The impressibility of the middle portion of the dorsum is greatly inferior ; but still, when the gustative sensation has been excited there, it is referred to the spot on which the sapid substance was laid. The contact of sapid substances much more readily excites a gustative sensation, when it is made to press upon the papill\u00e6, or to move over them. Thus there are some substances whose taste is not perceived when they are simply applied to the central part of the dorsum of the tongue, but of whose presence we are at once rendered cognizant by pressing the tongue against the roof of the mouth. The full flavour of a sapid substance, again, is more readily perceived when it is rubbed on any part of the tongue, than when it is simply brought in contact with it or pressed against it. Even when liquids are taken into the mouth, their taste is most completely discriminated by causing them to move over the gustative surface : thus the \u201cwine-taster\u201d takes a small quantity of the liquor into his mouth, carries it rapidly over every part of its lining membrane, and then ejects it. It is not improbable that this exaltation of the usual effects is simply due to mechanica causes ; the sapid particles being brought by the pressure or movement into more rapid and complete operation on the nerve-fibres, than they would be if simply placed in contact with the papill\u00e6.\nAs in the case of the other senses, so do we find with regard to that of taste, that continual attention to its indications greatly increases its acuteness. Thus the \u201c tasters \u201d of wine, tea, &c., acquire a power of discrimination which is truly wonderful to those who have not exercised themselves in the same manner. Thus we have been informed that the \u201c taster \u201d to one of the extensive cellars of sherry wines at Cadiz or Seville has not the least difficulty in distinguishing the butt from which a given sample may have been drawn, although the number of different varieties of the same kind of wine under his keeping may not be less than five hundred. So we are informed by Dr. Kitchener that many London epicures are capable of saying in what precise reach of the Thames the salmon on the table has been caught; and the Parisian gourmet is said to be able to distin-","page":861},{"file":"p0862.txt","language":"en","ocr_en":"862\nTASTE.\nguish by the taste, whether the birds on which he is dining are domesticated or wild, male or female, or to give an exact determination of the spices, &c., that are combined in a particular sauce.\nOn the other hand, the power of distinguishing sapors is for a time suspended, when several substances of very decided but different tastes are taken into the mouth in quick succession : thus, if sweet, sour, salt, or bitter substances be applied to the tongue, or if different kinds of wine be taken, one after another, the sense is so much blunted after a short time, as to impair or destroy the power of discrimination between them until after an interval of rest. So, again, when two substances of very different flavours are mingled together, the stronger will frequently mask the presence of the weaker : thus we often find it advantageous, in prescribing nauseous medicines, to combine with them aromatics, whose stronger impression shall take possession (so to speak) of the sense for a time ; and the object may be still more completely attained by giving the aromatic a moment or two previously, instead of simultaneously with the disagreeable substance.\nThe influence of habit in blunting the sensibility to particular tastes, is as remarkable as it is in the case of other sensations. Still more extraordinary, however, is the degree in which the taste may be educated to approve savours which are in the first instance most disgusting. \u201cThus,\u201d says Dr. Dunglison*, \u201c the Roman liquamen or garum, the most celebrated sauce of antiquity, was prepared from the half-putrid intestines of fish ; and one of the varieties of the Ottoq <n\\<piov, or laserpitium, is supposed to have been the assafeetida. Even at this time, certain of the Orientals are fond of the flavour of this nauseous substance. Putrid meat is the delight of some nations ; and a rotten egg, especially if accompanied with the chick, is highly esteemed by the Siamese. In civilised countries, w'e find game, in a putrescent state, eaten as a luxury ; this, to those unaccustomed to it, requires a true education. The same may be said of the pickled olive, and of several cheeses ; the fromage de Gruy\u00e8re, for example, so much esteemed by the inhabitants of continental Europe.\u201d Very extraordinary appetencies for particular flavours are sometimes morbidly developed ; as in the case of chlorotic girls, pregnant women, and insane patients. The latter will sometimes even devour their own excrement.\nIndependently of the changes produced by the education of the taste, we find great alterations in the likes and dislikes connected with it, taking place in accordance with the development of the body, or with other changes in its physiological conditions. Thus to the infant there is obviously nothing so agreeable as milk ; in more advanced childhood there is almost invariably a fondness for sweets ; whilst after adult age this is usually in a great degree superseded by a preference * Human Physiology, vol.i. p. 116.\nfor other savours. It sometimes happens that articles of diet which were peculiarly agreeable to us in childhood, become positively disgusting to us in later life ; whilst, on the contrary, many things to which we feel a strong distaste in childhood, are relished when we come to be men, and this by a spontaneous change in our own appetencies. We fully believe with Wagner that these alterations are in some way connected with the physical condition of the nutritive functions ; for we have other examples in which this connexion is very evident. Thus, we may continually remark that articles of food for which we have the keenest relish when we commence a meal with a good appetite, become positively distasteful when wre have already satisfied it. Again, we have known persons who have a positive repugnance to fatty or oleaginous matters of almost any description, so long as they reside in temperate climates, but who eat them with avidity when exposed to the severe cold of the arctic winter. And even in our own country we may frequently remark that the taste for such articles varies with the temperature ; a cup of sweet oleaginous cocoa, which would be almost loathed on a hot summer day, being very palatable on a cold winter night ; whilst ascescent drinks, such as would be greatly relished in the former season, are altogether discarded in the latter, except when a heated atmosphere brings back the physical condition of the system which renders them palatable.\nSo, again, we often observe in illness that an alteration in the physical conditions of the system so far affects the sense of taste, as to produce a great alteration in the usual appetencies. These alterations may probably be due in some instances to the depravation ot the buccal secretions, so that the gustative papillae are constantly surrounded with a substance possessing a certain taste of its own, which of course affects their impressibility by other savours. But there can be little doubt that they are more commonly occasioned by alterations in the condition of the gustative apparatus itself, which becomes the exponent (so to speak) of the wants of the system, and which may be trusted, to a very considerable extent, as indicating what is really most desirable for it. Thus Dr. Holland remarks * r \u2014 \u201c In the majority of instances of actual illness, provided the real feelings of the patient can be safely ascertained, his desires as to food and drink may be safely complied with. But undoubtedly much care is needful that w-e be not deceived as to the state of the appetites by what is merely habit or wrong impression on the part f>f the patient, or the effect of the solicitation of others. This class of sensations is more nurtured out of the course of nature than are those which relate to the temperature of the body. The mind becomes much more deeply engaged with them ; and though in acute iilness they are generally submitted again to the natural law, there are many lesser cases where * Medical Notes and Reflections, p. 85.","page":862},{"file":"p0863.txt","language":"en","ocr_en":"TASTE.\t863\nenough remains of the leaven of habit to reuder every precaution needful. With such precautions, however, which every physician who can take schooling from experience will employ, the stomach of the patient becomes a valuable guide ; whether it dictate abstinence from a recurrence to food ; whether much or little in quantity; whether what is solid or liquid; whether much drink or little; whether things warm or cold ; whether sweet, acid, or saline ; whether bland or stimulating to the taste.\u201d Further, Dr. Holland remarks : \u201c Tt is not wholly paradoxical to say that we are authorised to give greatest heed to the stomach when it suggests some seeming extravagance of diet. It may be that this is a mere depravation of the sense of taste ; but frequently it expresses an actual need of the stomach either in aid of its own functions or indirectly (under the mysterious law just referred to) for the effecting of changes in the whole mass of blood. It is a good practical rule in such cases to withhold assent till we find after a certain lapse of time that the same desire continues or strongly recurs ; in which case it may generally be taken as the index of the fitness of the thing desired for the actual state of the organs. In the early stage of recovery from long gastric fevers, I recollect many curious instances of such contrariety to all rule being acquiesced in, with manifest good to the patient. Dietetics must become a much more exact branch of knowledge, before we can be justified in opposing its maxims to the natural and repeated suggestions of the stomach, in the state either of health or disease.\u201d In regard to the use of wine in fever, it is universally admitted by practical physicians that very important indications may frequently be drawn from the appetency or dislike manifested towards it by the patient ; this being often exhibited when there is an almost entire obtuseness of the mind in regard to all other external impressions. In such circumstances these dormant instincts seem to manifest themselves, which are kept under by the intelligence in the normal condition; instincts akin to those which guide the lower animals in their choice of food. There is probably not a plant, however poisonous to most, which has not one or more species of animal specially adapted to derive from it wholesome nutriment, and which is obviously drawn to it by its odour or savour ; whilst the most omnivorous feeders, such as the monkey, are usually restrained by dislikes, excited through these same senses, from touching fruits which would be noxious to them.\nIt cannot be doubted that, in all persons of ordinary aptitude for the discrimination of flavours, there are certain natural harmonies and discords among these, as among colours and sounds ; so that particular substances of very different flavours taste agreeably in combination, whilst others are mutually repugnant. Thus every body likes sugar in combination with the acid of fruits ; and the sugar is popularly believed to neutralise the acid,\nwhich (as we need scarcely say) is not at all the case. On the other hand, sugar and oysters are said to form one of the most nauseous combinations possible. So, again, the flavour of many wines is improved by being tasted simultaneously with cheese, whilst it is injured by fruits.\u2014The art of cookery is founded upon a knowledge of these facts, which have not yet perhaps received from the scientific physiologist the systematic attention they deserve. Attempts have been made by Linnaeus, Boerhaave, and others, to form a classification of savours ; but no such classification has come into general use, although there are certain savours which all agree to consider primary ; such as the aromatic, the sweet, the acid, the bitter, the saline, the astringent, and the pungent. By the first of these the sense of taste is connected with that of smell ; by the last two with that of touch.\nThe impressions made upon the sense of taste seem to remain longer after the withdrawal of the body that excited them, than those which are received through most of our other senses. This is not surprising, when it is considered that particles of the sapid substance, which have once penetrated the pa-pill\u00e6, may linger there in contact with the sentient extremities of the nerves, for some little time after they have passed away from the external surface. In many cases, however, the substance leaves an after-taste which is different from that which it first excited. It is difficult to say how much of this may be due to the difference of the impression which is made upon the sensory papillae at the front of the tongue and upon those at its base, and also to the admixture of the olfactive sense, which will be most actively called into play as the sapid body is passing the fauces; and how much to the exhaustion of the nerves conser quent upon their previous stimulation, so that the after-taste is complementary to that first received. It certainly appears to confirm the former explanation, that the after-taste is generally of that bitterish character which we have seen to be produced by the mere mechanical stimulation of the papill\u00e6 at the base of the tongue. On the other hand, the fact that tannin, one of the bitterest substances known, has a sweetish after-taste, seems to favour the latter view. Probably both causes may participate in the production of the result.\nIt is not very common to find the sense of taste excited in a purely subjective manner ; since many of the tastes which are experienced in disease are probably due, as already remarked, to the depravation of the buccal secretions. Nevertheless, we occasionally meet with instances in which some peculiar gustative sensation, usually of a disagreeable nature, is constantly experienced without being traceable to any such cause ; and in which, therefore, we must seek for its occasion in some disqrdered functional condition of the sensorium.\nThe purpose of the sense of taste is obviously to serve as the guide and attraction towards","page":863},{"file":"p0864.txt","language":"en","ocr_en":"864\nTEETH.\nwholesome food, and to afford pleasure in the reception of it, whilst it deters from the use of such as would be deleterious. This is more obvious in the lower animals than it is in man, who is frequently led by habit and fashion to a preference for substances which are high-flavoured over those which are most wholesome, and who is still more frequently induced to gratify his gustative sense by the reception of an amount of food which appetite alone would not incite him to take in. Of the pernicious results of such excess, this is not the place to speak.\nThe only ulterior purposes which the sense of taste appears to perform in the economy, are to aicl in exciting the flow of saliva, and in certain cases to excite the act of vomiting. Although the secretion of saliva is greatly affected by other causes,\u2014as, for example, by the movement of the jaws, tongue, &c.,\u2014yet it is much influenced by the sapid qualities of the food introduced into the mouth, being greatly increased by the taste of savoury food. It is also augmented by the sight or odour of such food ; but it is probable that the latter sensations influence it not so much directly as indirectly, namely, through the ideas which they call up, for the idea alone, if called up with sufficient vividness, is sufficient to make ** the mouth water.\u201d The sense of nausea, as already remarked, seems intermediate between taste and touch ; but it is connected most closely with the former. We experience more or less of difficulty in swallowing all substances whose taste is peculiarly repugnant to us, and we find ourselves compelled to regurgitate them when the impression becomes of a certain intensity. This is one of the automatic actions in which it appears requisite that a sensation, not a mere impression, should participate.\n( William B. Carpenter.)\nTEETH.\u2014Comparative Anatomy.(Sing. a tooth; Tunth, Teut. ; Dens, Lat.; Dente, Ital.; Dent, Fr.; Tand, Dan. ; Tain, Old English ; Zahn, Germ. ; Dant, Welsh ; Dend, Erse ; o\u00eaov\u00e7-c\u00f4ovro\u00e7, Gr.; Dantis, Lithuanie; Dantas, Sanscrit.*) A tooth is a hard body attached to the mouth or commencement of the alimentary canal, always exposed, save where its development is permanently arrested, as in the rudi-mental tusk of the Narwhal ; commonly calcified, the exceptions being few, e. g., the horny teeth of the Lamprey and Platypus. Teeth vary not only in their tissue, but still more in number, size, form, structure, position, and mode of attachment, in different animals : they are principally adapted for seizing, tearing, dividing, pounding, or grinding the food ; in some they are modified to serve as weapons of offence and defence ; in others as aids in locomotion, means of anchorage, instru-\n* These synonyms are cited as illustrative of the\ncoincidence in one of the primary words of a natural class of languages that prevails from the East Indies, through the west of Asia and across Europe, and as indicative of the unity of stock of the great Indo-European family of mankind.\nments for uprooting or cutting down trees, or for transport and working of building materials ; they are characteristic of age and sex ; and in man they have secondary relations subservient to beauty and to speech.\nTeeth are always most intimately related to the food and habits of the animal, and are therefore highly interesting to the physiologist : they form for the same reason most important guides to the naturalist in the classification of animals ; and their value, as zoological characters, is enhanced by the facility with which, from their position, they can be examined in living or recent animals ; whilst the durability of their tissues renders them not less available to the palaeontologist in the determination of the nature and affinities of extinct species, of whose organisation they are often the sole remains discoverable in the deposits of former periods of the earth\u2019s history.\nAlthough there are many analogous structures in the inverterbrate classes, true calcified teeth are peculiar to the Vertebrata, and may be defined as bodies primarily, if not permanently, distinct from the skeleton, consisting of a cellular and tubular basis of animal matter containing earthy particles, a fluid, and a vascular pulp.\nIn general, the earth is present in such quantity as to render the tooth harder than bone, in which case the animal basis is gelatinous, as in other hard parts where a great proportion of earth is combined with animal matter. In a very few instances among the vertebrate animals, the hardening material exists in a much smaller proportion, and the animal basis is albuminous ; the teeth here agree, in both chemical and physical qualities, with horn.\nTrue teeth consist commonly of two or more tissues, characterised by the proportions of their earthy and animal constituents, and by the size, form, and direction of the cavities in the animal basis which contain the earth, the fluid, or the vascular pulp.\nThe tissue which forms the body of the tooth is called \u201cdentine,\u201d (Dentinum, Lat.; Zahnbein, Zahnsubstanz, Germ. ; VIvoire*, Fr.)\nThe tissue which forms the outer crust of the tooth is called ** cement \u201d (ccementum, crus fa petrosa, Lat.).\n* The learned author of the article \u201c Secretions,\u201d in the \u201cDictionnaire Universel d\u2019Histoire Naturelle,\u201d 8vo, 1848, adopts the term \u201c Dentine \u201d in preference to Cuvier\u2019s name \u201c ivoire,\u201d and after defining its properties, observes, \u201c Sur ces divers rapports, le mot dentine, par lequel M. E. Owen les d\u00e9signe, me para\u00eet tr\u00e8s heureux.\u201d The term \u201c ivory \u201d unavoidably recalls the idea of the peculiar modification of \u201c dentine,\u201d which characterises the tusks of the elephant, mammoth, and mastodon; but, besides this objection to its more general application, the word is used in a still wider sense in the \u201c Le\u00e7ons d\u2019Ana-tomie Compar\u00e9e : \u201d \u201c Les unes (dents), en effet, ont la partie enfonc\u00e9e dans l\u2019alv\u00e9ole d\u00e9nu\u00e9e d\u2019\u00e9mail; cette partie, ou la racine, ne se compose g\u00e9n\u00e9ralement que de Vivoire int\u00e9rieure, recouvert tr\u00e8s rarement d'ivoire ext\u00e9rieure (les dents de cachalot) ; \u201d torn. iv. Ed. posth. 1836, p. 200. The example cited of the tissue here denominated \u201c ivoire ext\u00e9rieure \u201d is the \u201c cement.\u201d See my \u201c Odontography,\u201d p. 355, pi. 89.","page":864},{"file":"p0865.txt","language":"en","ocr_en":"TEETH.\n865\nThe third tissue, when present, is situated between the dentine and cement, and is called \u201c enamel\u201d (encaustum, adamas, Lat.).\n\u201c Dentine \u201d consists of an organised animal basis disposed in the form of extremely minute tubes and cells, and of earthy particles : these particles have a twofold arrangement, being either blended with the animal matter of the interspaces and parietes of the tubes and cells, or contained in a minutely granular state in their cavities. The density of the dentine arises principally from the proportion of earth in the first of these states of combination, the tubes and cells contain, besides the granular earth, a colourless fluid, probably transuded \u201c plasma\u201d or \u201cliquor sanguinis,\u201d and thus relate not only to the mechanical conditions of the tooth, but to the vitality and nutrition of the dentine.\nThis typical structure of dentine is well illustrated in the article Tooth : such \u201c true dentine\u201d has no canals large enough to admit capillary vessels with the red particles of blood, and it has been therefore called \u201c un-vascular dentine.\u201d\nThe simplest modification of dentine is that in which capillary tracts of the primitive vascular pulp remain uncalcified, and permanently carry red blood into the substance of the tissue. These so-called \u201c medullary canals \u201d or \u201c vascular canals \u201d present various dispositions in the dentine which they modify, and which I have proposed to call \u201c vaso-dentine.\u201d It is often combined with true dentine in the same tooth ; e.g. in the scalpriform incisors of certain Rodents*, the tusks of the Elephant j-, the molars of the extinct Iguanodon.J\nA third modification of the fundamental tissue of the tooth is where the cellular basis of the dentine is arranged in concentric layers around the vascular canals, and contains \u201c radiated cells \u201d like those of the osseous tissue : it is called \u201c osteo-dentine.\u201d The transition from dentine to vaso-dentine, and from this to osteo-dentine, is gradual, and the resemblance of osteo-dentine to true bone is very close.\n\u201c Cement \u201d always closely corresponds in texture with the osseous tissue of the same animal ; and wherever it occurs of sufficient thickness, as upon the teeth of the horse, sloth, or ruminant, it is also traversed, like bone, by vascular canals. In reptiles and mammals, in which the animal basis of the bones of the skeleton is excavated by minute radiated cells, forming with their contents the \u201c corpuscles of Purkinje,\u201d these are likewise present, of similar size and form, in the \u201c cement,\u201d and are its chief characteristic as a constituent of the tooth. The hardening material of the cement is partly segregated and combined with the parietes of the radiated cells and canals, and is partly contained in disgregated granules in the cells, which are thus rendered white and opaque, viewed by reflected light. The relative density of the dentine and cement varies according to the\n* Odontography, 4to, p. 405.\nf lb. p. 643.\nJ lb. p. 251.\nVOL. IV.\nproportion of the earthy material, and chiefly of that part which is combined with the-animal matter in the walls of the cavities, as compared with the size and number of the cavities themselves. In the complex grinders of the elephant, the masked boar, and the capybara, the cement, which forms nearly half the mass of the tooth, wears down sooner than the dentine.\nThe \u201c enamel\u201d is the hardest constituent of a tooth, and, consequently, the hardest of animal tissues ; but it consists, like the other dental substances, of earthy matter arranged by organic forces in an animal matrix. Here, however, the earth is mainly contained in the canals of the animal membrane ; and, in mammals and reptiles, completely fills those canals, which are comparatively wide, whilst their parietes are of extreme tenuity. The hardening salts of the enamel are not only present in far greater proportion than in the other dental tissues ; but, in some animals, are peculiarly distinguished by the presence of fluate of lime.\nThe following are characteristic examples of the above-defined tissues, and their different combinations, in different teeth.\nThe examples are extremely few, and, as far as I know, are peculiar to the class Pisces, of calcified teeth which consist of a single tissue, and this is always a modification of dentine. The large pharyngeal teeth of the Wrasse (Labrus) consist of a very hard kind of unvascular dentine. Fig. 544. shows a ver-\njFig. 544.\nSection of pharyngeal tooth of Labrus, magnified, f Owen\u2019s Odontography. )J\ntical section of one of these teeth, supported upon the very vascular osseous tissue of the pharyngeal bone : p is the pulp cavity.\nThe next stage of complexity is where a portion of the dentine is modified by vascular canals. Teeth, thus composed of dentine and vaso-dentine, are very common in fishes. The hard dentine is always external, and holds the place, and performs the office, of enamel in the teeth of higher animals ; but it is only analogous to enamel, not the same\n3 K","page":865},{"file":"p0866.txt","language":"en","ocr_en":"866\nTEETH.\ntissue.* Fig. 545. illustrates this structure in a longitudinal section of a tooth of a shark of\nFig. 545.\nSection of tooth of L'amna, magnified.\n(Owen\u2019s Odontography.)\nthe genus Lavina : v is the vaso-dentine ; d the hard dentine; the earthy constituent so\nFig. 546.\nFig. 547.\nSection of tooth of Dugong ( Halicore), magnified. * Odontography, pp. 17. 37.\nSection of tooth of Cachalot (Physeter).\npredominates that the tissue takes a polish like enamel, for which it has commonly been mistaken in the teeth of fishes : I have called it \u201c vitro-den-tine.\u201d\nThe molars of the Dugong are examples of teeth composed of dentine and cement, the latter tissue forming a thick external layer. Fig. 546. A. is a transverse section of the crown of the second molar, natural size ; and B. a magnified view of a portion of the section ; d the dentine, remarkable for the number of minute calcigerous cells at its periphery ; and c the cement.\nIn the great teeth of the lower jaw of the Cachalot, the pulp-cavity of the growing tooth becomes filled up by steo-dentine, the result of a modified calci-cation of the dentinal pulp ; and the full-rown tooth presents three tissues, as shown","page":866},{"file":"p0867.txt","language":"en","ocr_en":"TEETH.\t867\nin fig. 547., in which c is the thick external cement, d the hard dentine, and o the osteo-dentine ; sometimes developed in loose stalac-titic-shaped nodules.\nIn the teeth of the Sloth, and its great extinct congener, the Megatherium, the hard dentine is reduced to a thin layer, and the chief bulk of the tooth is made up of a central body of vaso-dentine, and a thick external crust of cement. Fig. 548. represents a\nFig. 548.\nd\td\nSection of tooth of Megatherium.\nlongitudinal section of a lower molar of the Megatherium, of half the natural size : v is the vaso-dentine, d is the hard dentine, and c is the cement ; p is the base of the wide persistent pulp-cavity.\nThe hard dentine is, of course, the firmest tissue of a tooth so composed, and forms the crest of the transverse ridges of the grinding surface, like the enamel plates in the elephant\u2019s grinder. It has, consequently, been described to be enamel *, but its relation to that tissue is only one of analogy or function.\nThe human teeth, and those of the carnivorous mammals, appear at first sight to be composed of dentine and enamel only, as they were described to be by the Cuviers -J-, who\ni\n* Cuvier, Ossemens Fossiles, 4to, t. v., pt. 1., p. 172. ; and Clift, Transactions of the Geological Society, 1835, p. 438.\nf F. Cuvier, Dents de Mammif\u00e8res, p. 1. 8vo, 1825 ; G. Cuvier, Le\u00e7ons d\u2019Anat. Comp. iv. (1836), p. 199.\ncalled them, therefore, simple teeth ; but their crowns are originally, and their fangs are always, covered by a thin coat of cement. There is also commonly a small central tract of osteo-dentine in old teeth.\nIn fig. 7, pi. 122, of my Odontography is given a longitudinal section of a human molar tooth, in which d is the dentine, e the enamel, and c the cement.\nThe teeth, called by Cuvier compound or complex in Mammalia, differ, as regards their composition, from the preceding, only by the different proportion and disposition of the constituent tissues. Fig. 549. is a longitudinal section of the incisor of a horse ; d is the dentine, e the enamel, and c the cement ; c is the layer of cement reflected into the deep central depression of the crown ; and s is the coloured mass of tartar and particles of food which fills up that cavity, forming the \u201c mark\u201d of the horse-dealer. The characteristic structure of the three tissues is shown in the magnified part of the section, fig. 550.\nFig. 549.\nSection of incisor of a Horse {Equus).\nA very complex tooth may be formed out of two tissues by the way in which these may be interblended, as the result of an original complex disposition of the constituents of the dental matrix.\nCertain fishes, and a singular family of gigantic extinct Batrachians, which I have called \u201c Labyrinthodonts,\u201d* exhibit, as the name implies, a remarkable instance of this' kind of complexity. Fig. 551. is a view of a canine tooth of the Labyrinthodon salaman-droides, of the natural size : and fig. 552. is a slightly magnified view of a transverse section across the part of the crown marked a. At first view, the tooth appears to be of the simple conical kind, with the exterior surface merely striated longitudinally, but every streak is a fissure into which the very thin external layer of cement (c) is reflected into the body of\n* Proceedings of the Geological Society, Jan. 20\u00bb 1841, p. 257.\n3 K 2","page":867},{"file":"p0868.txt","language":"en","ocr_en":"868\nTEETH.\nFig. 550.\nMagnified portion of section of incisor of Horse ; c cement,, e enamel, d dentine.\nthe tooth, following the sinuous wavings of the lobes of dentine (d), which diverge from the central pulp-cavity, a.\nThe inflected fold of cement c runs straight for about half a line, and then becomes wavy, the waves rapidly increasing in breadth as they recede from the periphery of the tooth ; the first two, three, or four undulations are simple ; then their contour itself becomes broken by smaller or secondary waves ; these become stronger as the fold approaches the centre of the tooth, when it increases in thickness, and finally terminates by a slight dilatation or loop close to the pulp-cavity, from which the free margin of the inflected fold of cement is separated by an extremely thin layer of dentine. The number of the inflected converging folds of dentine is about fifty at the middle of the crown of the tooth figured, but is greater at the base. All the inflected folds of cement at the base of the tooth have the same complicated disposition with increased extent; but, as they approach their termination towards the upper part of the tooth, they also gradually diminish in breadth, and consequently penetrate to a less distance into the substance of the tooth. Hence, in such a section as is delineated (fig. 552.), it will be observed that some of the convoluted folds, as those marked ce, extend near to the centre of the tooth; others, as those marked c', reach only about half-way to the centre ; and those folds, c\", which, to use a geological expression, are \u201c cropping\nFig. 551.\nTooth of a Labyrinthodon, natural size.\nout,\u201d penetrate to a very short distance into the dentine, and resemble, in their extent and\nFig. 552.\nTransverse section of tooth of Labyrinthodon. (Magnified.')\nsimplicity, the converging folds of cement in the fangs of the tooth of the Ichthyosnurus.\nThe disposition of the dentine is still more complicated than that of the cement. It consists of a slender, central, conical column, excavated by a conical pulp-cavity for a cer-","page":868},{"file":"p0869.txt","language":"en","ocr_en":"TEETH.\n869\ntain distance from the base of the tooth 5 and this column sends radiating outwards, from its circumference, a series of vertical plates, which divide into two once or twice before they terminate at the periphery of the tooth.\nEach of these diverging and dichotomising plates gives off throughout its course smaller processes, which stand at right angles, or nearly so, to the main plate ; they are generally opposite, but sometimes alternate ; many of the secondary plates or processes, which are given off near the centre of the tooth, also divide into two before they terminate; and their contour is seen, in the transverse section, to partake of all the undulations of the folds of cement which invest and divide the dentinal plates and processes from each other.\nThe dental pulp-cavity is reduced to a mere line about the upper third of the tooth, but throughout its whole extent fissures radiate from it, corresponding in number with the radiating plates of dentine. Each fissure is continued along the middle of each plate, dividing where this divides, and extending along the middle of each bifurcation and process to within a short distance of the line of cement. The pulp-fissure commonly dilates into a canal at the origin of the lateral processes of the radiating plates, before it divides to accompany and penetrate those processes.\nThe main fissures or radiations of the pulp-cavity extend to within a line or half a line of the periphery of the tooth, and suddenly dilate at their terminations into spaces, which, in transverse section, are subcircular, oval, or\nrally smaller spaces. All these spaces, or canals, in the living tooth, must have been occupied by corresponding processes of the vascular pulp : they constitute so many centres of radiation of the fine calcigerous tubes, which, with their uniting clear substance, constitute the dentine.*\nAn analogous complexity is produced by numerous fissures radiating from a central mass of vaso-dentine, which more or less fills up the pulp-cavity of the seemingly simple conical teeth of the extinct family of fishes which I have called \u201c Dendrodontsd\u2019f Fig. 553. is one of these fossil teeth, of the natu-\nFig. 553.\nTooth of a Dendrodus, natural size.\nral size ; a a transverse section ; and fig. 554 a reduced view of a portion of the same section, enlarged twenty diameters.\nThus magnified, a central pulp-cavity, of\nTransverse section of tooth of Dendrodus. A, natural size ; B, the portion c, of A, magnified 20 diameters.\npyriform, p : the branches of the radiating relatively small size, and of an irregular lobu-lines, which are continued into the lateral lated form, is discerned, a portion of which secondary plates or processes of the dentinal * Odontography, pp. 195\u2014217, pi. 64a, 64b. lamell\u00e6, likewise dilate into similar, and gene- f lb. p. 171.\n3 k 3","page":869},{"file":"p0870.txt","language":"en","ocr_en":"870\nTEETH.\nis shown at p; this is immediately surrounded by the transverse sections of large cylindrical medullary, or pulp-canals of different sizes; and, beyond these, there are smaller and more numerous medullary canals, which are processes of the central pulp-cavitv. In the transverse section these processes are seen to be connected together by a net-work of smaller medullary canals belonging to a coarse osseous texture into which the pulp has been converted, and this structure occupies the middle half of the section. All the medullary canals were filled by the opaque matrix. From the circumference of the central network, straight medullary fissures radiate at pretty regular intervals to the periphery of the tooth : most of these canals divide once, rarely twice, in their course; the division taking place sometimes at their origin, in others at different distances from their terminations, and the branches diverge slightly as they proceed. Each of the above medullary fissures is continued from a short process of the central structure, which is connected by a concave line with the adjoining process, so that the whole periphery of the transverse section of the central coarse reticulo-medul-lary body of the tooth presents a crenate outline. From each ray and its primary dichotomous divisions, short branches are sent off at brief intervals, generally at right angles with the trunk, or slightly inclined towards the periphery of the tooth. These subdivide into a few short ramifications, like the branches of a shrub, and terminate in irregular and somewhat angular dilatations, simulatingleaves, but which resolve themselves into radiating fasciculi of calcigerous tubes. There are from fifteen to twenty-five or thirty-six of these short and small lateral branches on each side of the medullary rays.\nA third kind of complication is produced by an aggregation of many simple teeth into a single mass.\nThe examples of these truly compound teeth* are most common in the class of Fishes, but the illustration here selected is from the Mammalian class. Each tooth of the Cape Ant-eater (Orycteropus) presents a simple form, is deeply set in the jaw, but without dividing into fangs; its broad and flat base is porous, like the section of a common cane. The canals to which these pores lead contain processes of a vascular pulp, and are the centres of radiation of as many inde-\n* In the \u201c Le\u00e7ons d\u2019Anatomie Compar\u00e9e \u201d of Cuvier, the teeth, in which folds of enamel and cement penetrate the entire substance of the crown, are called \u201c compound : \u201d \u201c Nous appelions \u2018 dent compos\u00e9e \u2019 celle dont les diff\u00e9rentes substances forment des replis tellement profonds, que dans quelque sens qu\u2019on coupe la dent, on coupe plusieurs fois chacune des substances qui la composent : telles sont les dents molaires de l'El\u00e9phant.\u201d The teeth of the \u201c Labyrinthodonts \u201d would come under this definition more truly than those of the elephant, although they differ from them in having no enamel ; for a molar of an elephant might be bisected, vertically and transversely, without cutting the tissues across more than once.\npendent series of dentinal tubules. Each tooth, in fact, consists of a congeries of long and slender prismatic denticles of dentine, which are cemented together by their ossified capsules, the columnar denticles slightly decreasing in diameter and occasionally bifurcating as they approach the grinding surface of the tooth.\nA figure of a longitudinal section of the molar teeth is given in PI. 76, fig. 10. of my \u201c Odontography,\u201d and a magnified view of a similar section in PI. 77. ; fig. 555. gives a magnified view of a portion of the transverse\nFig. 555.\nPart of transverse section o f the tooth of the Orycteropus. {Magnified.}\nsection of the fourth molar, showing c the cement; d the dentine; p the pulp-cavity of the denticles ; and d' a section of one of the denticles just beyond its bifurcation.\nThe pectinated incisors of the flying Lemur of the Indian Islands (Galeopithecus) are examples of teeth, the crowns of which are composed of denticles consisting of hard dentine, with a covering of true enamel. The layer of cement over this is too thin to show its characteristic structure, and does not fill up the intervals of the denticles, which stand out as free processes from the base of the crown. Tubular prolongations of the pulp-cavity are continued up the centre of each denticle.\nFig. 556. exhibits a longitudinal section, magnified, of this kind of compound tooth; dis the dentine; e the enamel; p the pulp-cavity. The originally detached summits of the crown of the human incisor are homologous with these columnar processes, or denticles of the incisor of the Galeopithecus.\nIn the compound molars of the great African wart-hogs (Phacoch\u0153rus) the columnar denticles are in three rows, and their interspaces are filled up by cement : each denticle consists of a slender column of hard dentine inclosed in a thick sheet of enamel, the whole being bound together by the cement ; and the","page":870},{"file":"p0871.txt","language":"en","ocr_en":"TEETH.\n871\ndenticles, as in the Galeopithecus, blending long diameter of the tooth. When the tooth together into a common base in the fully-de- is bisected vertically and lengthwise, the three veloped tooth.\tsubstances, d dentine, e enamel, and c cement,\nFig. 556.\nF'g. 557.\nSection of lower incisor of Galeopithecus (.Magnified.)\nA figure is given of the grinding surface of the third true molar of the Phacoch\u0153rus Pal-\nSection of molar of Elephant.\nare seen interblended as in fig. 557., in which p is the common pulp-cavity, and r one of the roots of this complex tooth.\nA still more complex grinding apparatus is found in certain fishes. The lower pharyngeal bone of the parrot-fish (Scarus*), for example, supports a dental plate with a tri-\nFig. 558.\nTwo of the upper pharyngeal teeth, Scarus. (Magnified.)\nlasii, in PI. 140, fig. 4, of my \u201c Odontography.\u201d turating surface like that of the compound In the elephant the denticles of the com- molars of the Phacoch\u0153rus. The interlocked pound molars are in the form of plates, vertical upper pharyngeals {fig. 565.) support dental to the grinding surface and tranverse to the\t* Odontography, pi. 51., fig. 3.\n3 k 4","page":871},{"file":"p0872.txt","language":"en","ocr_en":"872\tTEETH.\nmasses with a grinding surface more like that of the compound molars of the elephant.\nWhen a vertical and longitudinal section is made of one of these upper pharyngeal compound teeth, each denticle is seen to be composed, as in fig. 558., of a body of very hard and unvascular dentine d, with a thick sheath of enamel e, the denticles being united together by the cement c, and supported and further united together, and to the pharyngeal bone, by a basal mass of vascular osteo-dentine.\nSuch are some of the prominent features of a field of observation which comparative anatomy opens out to our view ;\u2014such the varied nature, and such the gradation of complexity of the dental tissues, which, up to December 1839*, continued, notwithstanding successive approximations to the truth, to be described in systematic works as a \u201c pha-neros,\u201d or \u201c a dead part or product exhaled from the surface of a formative bulb ! \u201d The truth may be slowly but is surely established, subject to the usual attempts to mask or detract from the merit of the discovery. By no systematic authors has the hypothesis of the formation of dentine by transudation or secretion been more frequently or more explicitly enunciated than by the Cuviers. Baron Cuvier repeats, in both editions of his elaborate work \u2014 the \u201c Ossemens Fossiles \u201d \u2014 \u201c C\u2019est dans ce vide con\u00e7evable que se d\u00e9poseront les mati\u00e8res qui doivent former la dent, savoir: la substance vulgairement appel\u00e9e osseuse, qui sera transud\u00e9e par des productions g\u00e9latineuses venant du fond de la ' capsule, et l\u2019\u00e9mail qui sera d\u00e9pos\u00e9 par les cloisons membraneuses,\u201d t.ii. p. 61., ed. 1812.; t. i. p. 33., ed. 1821. See, also, M. F. Cuvier, \u201c Dents de Mammif\u00e8res,\u201d 8vo, 1825. \u201c L\u2019ivoire se d\u00e9pose par couches concentriques,\u201d p. xxvii. ; \u201c L\u2019\u00e9mail se d\u00e9pose dans un sens contraire \u00e0 l\u2019ivoire,\u201d ib. p. xxviii. And Baron Cuvier again, in the second edition of his \u201cLe\u00e7ons d\u2019Anatomie Compar\u00e9e,\u201d t. iv. 1836, p. 214 : \u201cL\u2019ivoire se d\u00e9pose par couches, par une sorte de transudation.\u201d In the first edition of this classical work, Cuvier had illustrated the peculiarity of the teeth of certain fishes, which are at first detached and afterwards united to the jaw-bone, by comparing their growth to that of the epiphyses of the long bones : \u201c Mais les dents qui ne tiennent qu\u2019\u00e0 la gencive seulement, comme celle des Squales, croissent \u00e0 la mani\u00e8re des epiphyses des os, c\u2019est-\u00e0-dire que toute leur substance osseuse est d\u2019abord tendre et poreuse, et qu\u2019elle se durcit uniform\u00e9ment, et finit par devenir enti\u00e8rement dure comme de l\u2019ivoire,\u201d t. iii. 1805, p. 112. Whether the great anatomist meant to imply that the\n* See the Fasciculus of M. de Blainville\u2019s great work, \u201c Ost\u00e9ographie et Odontographie d\u2019Animaux Vert\u00e9br\u00e9s,\u201d which he submitted to the Academy of Sciences of the Institute of France on the same day, December 16th, 1839, on which I communicated, on the occasion of my election as corresponding member of that body, my \u201c Theory of the development of dentine by centripetal calcification and conversion of the cells of the pulp.\u201d\nosseous tissue of the epiphyses of bones was developed differently from osseous tissue in general, e. g. by the uniform and simultaneous hardening or calcification, obscurely referred to in the above quotation, may be questioned, for such is not the way in which the teeth of the shark are calcified. But this is certain, that the idea, whatever it might have been, had no influence on the fixed belief of the developement of the dental tissue by transudation expressed in their later and more elaborate works by Baron Cuvier and his accomplished brother ; and, in point of fact, the passage which I have quoted is expunged from the second edition of the \u201c Le\u00e7ons d\u2019Anatomie Compar\u00e9e,\u201d 1835 : the successive stages of calcification in the different teeth of the same vertical series in the jaw of the shark, having probably been noticed in the interim by Cuvier.\nThe author of the article \u201c S\u00e9cr\u00e9tions \u201d in the \u201cDictionnaire Universel d\u2019Histoire Naturelle,\u201d has, however, reproduced Cuvier\u2019s obscure comparison of certain fishes\u2019 teeth to the epiphyses of bone, as evidence of the needlessness of any ulterior researches for the demonstration of the theory of dental developement by conversion and calcification of the pulp. The passage from the third vol. of the old edition (1800) of the \u201c Le\u00e7ons d\u2019Anat. Comp.,\u201d p. 112, is cited to show that it naturally conducts to the knowledge of such mode of developement of dentine : \u201c En 1840 et 1841 (the \u2018 Comptes Rendus del\u2019Acad, des Sciences\u2019 give the true date) l\u2019\u00e9tude des dents de Squale par M. R. Owen, lui a d\u00e9montr\u00e9e leur accroissement par intussusception, comme elle avait \u00e9t\u00e9 \u00e0 Gr. Cuvier trente-cinq ann\u00e9es auparavant.\u201d How or why Gr. Cuvier came to abandon the theory so demonstrated, and how it happened that none of his contemporaries adopted it, M. Duvernoy does not explain. He does give a reason for the omission, in the second edition of the \u201c Le\u00e7ons d\u2019Anat. Comp.\u201d of the passage which he affirms to contain the demonstration : \u201c Malheureusement, le copiste de cet ancien texte pour la 2de \u00e9dition a omis ce passage, par oubli.\u201d It was natural to conclude that its obscurity and seeming contradiction to the theory of dental developement, formally propounded by Cuvier, as well as to the facts shown by nature in the sharks, had been the cause of its omission ; but even had the misfortune to which M. Duvernoy now attributes that omission (for in the copious list of addenda and corrigenda to the fifth, 1837, and final, 1846, volumes it is not noticed) not occurred, the coincidence of such passages as the following would still have been inexplicable and irreconcilable with the deductions that M. Dumeril is now enabled to draw from the comparison of the shark\u2019s tooth with the epiphyses of long bones. \u201c L\u2019ivoire se d\u00e9p\u00f4se par couches, par une sorte de transudation.\u201d Le\u00e7ons d\u2019Anat. Compar\u00e9e, t. iv., 1836, p. 214. To which proposition Cuvier has himself added a note : \u201c Je me suis assur\u00e9 r\u00e9cemment, sur des germes de dents d\u2019\u00e9l\u00e9phant, que la substance osseuse de la dent se forme comme","page":872},{"file":"p0873.txt","language":"en","ocr_en":"TEETH.\t873\nles coquilles.\u201d And the editor (M. Duvernoy), in order to obviate any possibility of misconception, has himself subjoined a note to that passage, as follows : \u201c L'ivoire a \u00e9t\u00e9 aussi appell\u00e9 substance osseuse, \u00e0 cause de son analogie de composition chimique et de duret\u00e9 avec les os. Mais la nature inerte et inorganique de cette substance, mieux appr\u00e9ci\u00e9e dans ces derniers temps, surtout par les travaux de M. Cuvier, ne permet plus de la d\u00e9signer, avec justesse, par cette seconde expression. Du moins est-il n\u00e9cessaire de pr\u00e9munir le lecteur contre l\u2019ide\u00e9 fausse qu\u2019il pourrait en tirer, qu\u2019elle serait organis\u00e9e, qu\u2019elle se d\u00e9velopperait \u00e0 la mani\u00e8re des os.\u201d\u2014Tom. cit. p. 201, (1836). In the same spirit in which M. Duvernoy sees (in 1848) that a true idea, instead of a false one, may be drawn fi'om casual expressions and similies loosely applied in the old Le\u00e7ons of 1800 and 1805 ; others have sought to depreciate the value of the establishment of the truth by citing the doubts, or tentative approximations made by Purkinje and Schwann to my theory, interpreting such approximations by the light of the established truth. So far from finding such a resting-place for doubt in Cuvier\u2019s early simile, cited by M. Duvernoy in 1848, or in the interrogatories of Schwann, nothing short of the investigation of the whole of this vast subject, zootomically, develop-mentally, and microscopically, as narrated in my \u201c Odontography,\u201d sufficed to settle my own doubts ; and nothing short of the evidence and illustrations given in that work appeared to me adequate to convert anatomists from the excretion-hypothesis to the intussusception theory.\nThat the dentine is the ossified pulp is an older notion than that it is an inorganic secretion from such pulp. But an hypothesis, to be of any value in science, must be proved. Almost every true theory has been indicated, with various degrees of approximation, before its final establishment : but he has ever been held, in exact philosophy, to be the author of a theory, by whom it has been first rightly enunciated and satisfactorily established. When time has dissipated the mists of individual or national rivalries and jealousies, the name of the true discoverer is clearly seen by the inextinguishable light of true and impartial history : and to that period I look forward with calm and confident hope.\nI proceed now to briefly point out the leading characteristics of the teeth in the different classes of the vertebrate animals.\nDental System of Fishes.\nThe teeth of fishes, whether we study them in regard to their number, form, substance, structure, situation, or mode of attachment, offer a greater and more striking series of varieties than do those of any other class of animals.\nAs to number, they range from zero to countless quantities. The Lancelet, the Am-mocete, the Sturgeon, the Paddle-fish, and the whole, order of Lophobranchii, are eden-\ntulous. The Myxinoids have a single pointed tooth on the roof of the mouth {fig. 559\u201e a), and two serrated dental plates (b) on the\nFig. 559.\nMyxine. {M\u00fcller.')\ntongue. The Tench {fig. 514. Vol. III. p. 979. art. Pisces)* has a single grinding tooth on the occiput (c), opposed to two dentigerous pharyngeal jaws below {dd). In the Lepidosiren a single maxillary dental plate {fig. 560., a) is opposed to a single mandibular\nFig. 560.\nLepidosiren.\none {b), and there are two small denticles on the nasal bone (c). In the extinct Sharks with crushing teeth, called Ceratodus and Cte-nodus, the jaws were armed with four teeth, two above and two below.f In the Chim\u0153r\u00e6, two mandibular teeth are opposed to four maxillary teeth.| From this low point the number in different fishes is progressively multiplied until, in the Pike, the Siluroids {fig. 56].), and many other fishes, the mouth becomes crowded with countless teeth.\nWith respect to form, I may first observe, that as organised beings withdraw themselves more and more, in their ascent in the scale of life, from the influence of the general polarising forces, so their parts progressively deviate from geometrical figures : it is only, therefore, in the lowest vertebrated class that we find teeth in the form of perfect cubes, and of prisms or plates with three sides {Myletes), four sides (Scarus), five or six sides, Mylio-bates {fig. 562.). The cone is the most common form in fishes : such teeth may be slender, sharp-pointed, and so minute, numerous, and closely aggregated, as to resemble the plush or pile of velvet ; these are called \u201c villi form teeth\u201d {dentes villiformes, dents en velours\u00a7) ; all the teeth of the Perch are of this kind :\n* And Odontography, pi. 57 .fig. 5.\nf See Odontography, pi. 22, figs. 2. 6, 7.\nt lb., pi. 28, figs. 1, 2. 4. 6.\n\u00a7 The French terms are those used by Cuvier and Valenciennes in their great \u201c Histoire des Poissons,\u201d 4to.","page":873},{"file":"p0874.txt","language":"en","ocr_en":"874\nTEETH.\nwhen the teeth are equally fine and numerous, but longer, they are called \u201c ciliiform \u201d (dentes\nFig. 561.\nPalatine hone and teeth (Silurus).\nciliiformes) : when the teeth are similar to, but rather stronger than these, they are called\nFig. 562.\nJaws and teeth (.Myliobates).\n\u201c setiform\u201d (dentes setifonnes, dentes en brosse) : conical teeth, as close set and sharp pointed\nas the villiform teeth, but of larger size, are called \u201c rasp-teeth \u201d (dentes radultformes, dents en rape or en eardesfifig. 561.) ; the Pike presents such teeth on the back part of the vomer : the teeth of the Sheat-fish (Silurus glanis) present all the gradations between the villiform and raduliform types. Setiform teeth are common in the fishes thence called Ch\u00e6-todonts* ; in the genus Citharina they bifurcate at their free extremities ; in the genus Platax they end there in three diverging points (fig. 563.), and the cone here merges into the long and slender cylinder. Sometimes the cone is compressed into a slender trenchant blade : and this may be pointed and\n* Xamj, bristle ; ilovs, tooth.\nrecurved, as in the Mur\u0153na; or barbed, as in Trichiurus, and some other Scomberoids ; or it may be bent upon itself, like a tenterhook, as in the fishes thence called (loniodonts.* In the Bonito may be perceived a progressive thickening of the base of the conical teeth : and this being combined in other predatory\nFig. 563.\nMandibular teeth, magnified (Platax).\nfishes with increased size and recurved direction, they then resemble the laniary or canine teeth of carnivorous quadrupeds, as we see in the large teeth of the Pike, in the Lophiusf, and in certain sharks.^:\nThe anterior diverging grappling teeth of the wolf-fish form stronger cones ; and by progressive blunting, flattening, and expansion of the apex, observable in different fishes, the cone gradually changes to the thick and short cylinder, such as is seen in the back\nFig. 564.\nInferior pharyngeal bone and teeth (Labrus).\nteeth of the wolf-fish, and in similar grinding and crushing teeth in other genera, whether feeders on sea-weeds, or crustaceous and testaceous animals. The grinding surface of these short cylindrical teeth maybe convex, as in the Sheep\u2019s-head fish (Sargus) ; or flattened, as in the pharyngeal teeth of the Wrasse (La-brus).\u00a7 Sometimes the hemispheric teeth are so numerous, and spread over so broad a surface, as to resemble a pavement, as in the pharyngeal bones of the Wrasse or Rock-fish (Labrus, fig. 564.) ; or they may be so small, as well as numerous (dentes graniformes), as to give a granulated surface to the part of the mouth to which they are attached (premax-illaries of Cossi/phus). || A progressive increase\n* IW\u00ab, an angle ; \u00abSo\u00f9-r, a tooth.\nf Yol. Ill.,fig. 512, p. 978. art. Pisces.\nJ lb .fig. 510, p. 976.\n\u00a7 ^6. fig. 513, p. 978.\nI] Odontography, pi. 45, fig. 1.","page":874},{"file":"p0875.txt","language":"en","ocr_en":"TEETH.\n875\nof the transverse over the vertical diameter may be traced in the molar teeth of different fishes, and sometimes in those of the same individual, as in Labrus (fig. 564.), until the cylindrical form is exchanged for that of the depressed plate. Such dental plates (dentes lamelliformes) may be found, not only circular, but elliptical, oval, semilunar, sigmoid, oblong, or even square, hexagonal, pentagonal, or triangular ; and the grinding surface may present various and beautiful kinds of sculpturing. The broadest and thinnest lamelliform teeth are those that form the complex grinding tubercle of the Diodon.* The front teeth of the Flounder and Sargus present the form of compressed plates, at least in the crown, and are true dentes incisivi. Numerous wedge-shaped dental plates (dentes cuneati) are set vertically in the upper pharyngeal bones of the Parrot-fish {Scaras, fig. 565.). A thin\nFig. 565.\nSuperior pharyngeal hones and teeth ( Scarus).\nlamella, slightly curved like a finger-nail, is the singular form of tooth in an extinct genus of fishes, which I have thence called Petalodus. Sometimes the incisive form of tooth is notched in the middle of the cutting edge, as in Sargus unbnaculatus. Sometimes the edge of the crown is trilobate (Aplodactylus, fig. 566.).\nFig. 566.\nFront teeth of Aplodactylus.\nSometimes it is made quinquelobate by a double notch on each side of the large middle lobe (Boops). In the formidable Sea-pike\nt Odontography, pi. 38, fig. 2 ; and art. Pisces, Yol. III. p 980, fig. 517.\n(Sphyrcena Barracuda) the crown of each tooth, large and small, is produced into a compressed and sharp point, and resembles a lancet. Sometimes the edges of such lancet-shaped teeth are finely serrated, as in Priodon, and the great Sharks of the genus Carcharias, the fossil teeth of which indicate a species (Carch. Megalodon) sixty or seventy feet in length.\nThe lancetted form is exchanged for the stronger spear-shaped tooth in the Sharks of the genus Lamna; and in the allied great extinct Otodus, as in the small Porbeagle, similarly shaped, but stronger, piercing and cutting teeth were complicated by one or more accessory compressed cusps on each side their base, like the Malay crease.\nWith respect to situation, the teeth, in Sharks and Rays, are limited to the bones (maxillary and mandibular), which form the anterior aperture of the mouth : in the Carp and other Cyprinoids the teeth are confined to the bones (pharyngeal and basi-occipital) which circumscribe the posterior aperture of the mouth. The Wrasses (Labrus) and the Parrot-fishes (Scarus) have teeth on the pre-maxillary and pre-mandibular, as well as on the upper and lower pharyngeals ; both the anterior and posterior apertures of the mouth being thus provided with instruments for seizing, dividing, or comminuting the food, the grinders being situated at the pharynx. In most fishes teeth are developed also in the intermediate parts of the oral cavity, as on the palatines, the vomer, the hyoid bones, the branchial arches ; and, though less commonly, on the pterygoids, the entopterygoids, the sphenoids, and even on the nasal bone (fig. 560, c.). It is very rare to find teeth developed on the true superior maxillary bones ; but the Herring and Salmon tribes, some of the Ganoid Fishes, and the great Sudis, are examples of this approach to the higher Vertebrata. Among the anomalous positions of teeth may be cited, besides the occipital alveolus of the Carp *, the marginal alveoli of the prolonged, depressed, well ossified rostrum of the Saw-fish, Pristis. In the Lampreys and in Helostomus (an osseous fish), most of the teeth are attached to the lips. Lastly, it is peculiar to the class Pisces, amongst Vertebrata, to offer examples of teeth developed in the median line of the mouth, as in the palate of the Myxines (fig. 559, a.) ; or crossing the symphysis of the jaw, as in Notidanus, Scymnus, and Myliobates.\nNor is the mode less varied than the place of attachment. The teeth of Lophius, Pos-cilia, Anableps, are always moveable. In most fishes they are anchylosed to the jaws by continuous ossification from the base of the dental pulp ; the histological transition being more or less gradual from the structure of the tooth to that of the bone. Sometimes we find, not the base, but one side of the tooth anchylosed to the alveolar border of the jaw ; and the teeth oppose each other by\n* Odontography, pi. 8 ; and art. Pisces, Yol. III., p. 980, fig. 518.","page":875},{"file":"p0876.txt","language":"en","ocr_en":"876\tTEETH.\ntheir sides instead of their summits (Scarns*); in Pimelodus, however, where the teeth are thus attached, the crown is bent down in the upper teeth, and bent up in the lower ones, at right angles to the fang, so that they oppose each other by the normal surfaces. Certain teeth of recent and fossil cartilaginous fishes have their base divided into processes like fangs, but these serve for the attachment of ligaments, and are not set in bony sockets like the true fangs or roots of the teeth of the Mammalia. Some Sharks have two divaricating fangs ; some fossil teeth referred to my genus Petalodus by Agassiz, with the specific name \u201c radicans,\u201d have the base divided into several fangs or processes, indicating a generic distinction. The base of anchylosed teeth is, at first, attached to the jaw-bone by ligament ; and in the Codfish, Wolf-fish, and some other species, as calcification of the tooth progresses towards its base, the subjacent portion of the jawbone receives a stimulus, and developes a process corresponding in size and form with the base of the tooth : for some time a thin layer of ligamentous substance intervenes, but anchylosis usually takes place to a greater or less extent before the tooth is shed. Most of the teeth of the Lophius retain the primitive ligamentous connection ; the ligaments f of the large internal or posterior teeth of the upper and lower jaws, radiate on the corresponding sides of the bone, the base of the tooth resting on a conformable alveolar process. The ligaments do not permit the tooth to be bent outwards beyond the vertical position, but yield to pressure in the contrary direction, by which the point of the tooth may be directed towards the back of the mouth ; the instant, however, that the pressure is remitted, the tooth returns through the elasticity of the bent ligaments, as by the action of a spring, into its usual erect positions (fig. 512, c.c. Vol. III. p. 978. art. Pisces) ; the deglutition of the prey of this voracious fish is thus facilitated, and its escape prevented.J The broad and generally bifurcate bony base of the teeth of Sharks is attached by ligament to the semi-ossified crust of the cartilaginous jaws $ ; but they have no power of erecting or depressing the teeth at will. The small and closely crowded teeth of Rays are also connected by ligaments to the subjacent maxillary and mandibular membranes. The broad tes-selated teeth of the Myliobates have their attached surface longitudinally grooved to afford them better hold-fast, and the sides of the contiguous teeth are articulated together by serrated or finely undulating sutures, a structure unique in dental organisation. || The teeth of the Sphyr\u0153na are examples of the ordinary implantation in sockets, with the addition of a slight anchylosis of the base of the fully-formed tooth with the alveolar pa-\n* Odontography, pi. 49 ; and art. Pisces, Yol. III. fig. 516, p. 979.\nf See art. Pisces, Vol. 111., fig. 512 d, p. 978.\nj Odontography, p. 154.\n\u00a7 Art. Pisces, Vol. III., fig. 510, p. 976.\n|| Odontography, p. 46. pi. 27 c.\nrietes ; and the compressed rostral teeth of the Saw-fish are deeply implanted in sockets. In the latter the hind margin of their base is grooved, and a corresponding ridge from the back part of the socket fits into the groove, and gives additional fixation to the tooth. Some implanted teeth in the present class have their hollow base further supported, like the claws of the feline tribe, upon a bony process arising from the base of the socket ; the incisors of the Balistes, e.g., afford an example of this double or reciprocal gomphosis. In fact, the whole of this part of the organisation of fishes is replete with beautiful instances of design, and instructive illustrations of animal mechanics. The vertical section of a pharyngeal jaw and teeth of the Wrasse (Labrus *) would afford the architect a model of a dome of unusual strength, and so supported as to relieve from pressure the floor of a vaulted chamber beneath. The base of the domeshaped tooth is slightly contracted, and is implanted in a shallow circular cavity; the rounded margin of which is adapted to a circular groove in the contracted part of the base; the margin of the tooth which immediately transmits the pressure of the bone, is strengthened by an inwardly projecting convex ridge. The masonry of this inner buttress, and of the dome itself, is composed of hollow columns, every one of which is placed so as best to resist or transmit in the due direction the external pressure. The floor of the alveolus is thus relieved from the office of sustaining the tooth : it forms, in fact, the roof of a lower vault, in which the germ of a successional tooth is in course of development ; had the crushing tooth in use, rested, as in the Wolf-fish, by the whole of its base upon the alveolus, the supporting plate, gradually undermined by the growth of the new tooth, must have given way, and been forced upon the subjacent delicate and highly vascular and sensitive matrix of the half-formed tooth. But the superincumbent pressure is exclusively sustained by the border of the alveolus, whence it is transferred to the walls dividing the vaulted cavities containing the germs of the new teeth ; the roofs of these cavities yield to the absorbent process consequent on the growth of the new teeth without materially weakening the attachment of the old teeth, and without the new teeth being subjected to any pressure until their growth is sufficiently advanced to enable them to bear it with safety ; by this time the sustaining borders of the old alveolus are undermined, and the old worn-down tooth is shed.\nThe singular and powerfully developed dental system of the Wolf-fish (Anarrhi-chas Lupus) has been a subject of interest to many anatomists. The general character and physiological relations of the teeth in this species had not escaped the attention of Hunter. In his paper on the Gillaroo trout, read before the Royal Society in 1774, he observes that \u201c the teeth of fishes which subsist\nFig. 544 ; and art. Pisces, Vol. III., fig. 513, p. 978.","page":876},{"file":"p0877.txt","language":"en","ocr_en":"TEETH.\t877\nchiefly on animal matter must vary according as their food may be common salt fish, or shell-fish.\u201d \u201c Such fish as live on the first kind have, like the carnivorous quadrupeds and birds, no apparatus for mastication, their teeth being intended merely for catching the food and fitting it to be swallowed. But the shells of the second kind of food render some degree of masticatory power necessary to fit it for its passage either into the stomach or through the intestines : and accordingly we find in certain fish a structure suited to the purpose. Thus the mouth of the Wolf-fish is almost paved with teeth, by means of which it can break shells to pieces, and fit them for the oesophagus of the fish, and so effectually disengage the food from them, that though it lives upon such hard food, the stomach does not differ from that of other fish.\u201d\nBut in order to secure the capture of the shell-fish, the teeth of the Wolf-fish are not all crushers ; some present the laniary type, with the apices more or less recurved and blunted by use, and consist of strong cones spread abroad, like grappling hooks, at the anterior part of the mouth.*\nThe premaxillary teeth are all conical, and arranged in two rows; there are two, three, or four in the exterior row, at the mesial half of the bone, which are the largest ; and from six to eight smaller teeth are irregularly arranged behind. There are three large, strong, diverging laniaries at the anterior end of each premandibular bone, and immediately behind these an irregular number of shorter and smaller conical teeth, which gradually exchange this form for that of large obtuse tubercles ; these extend backwards, in a double alternate series, along a great part of the alveolar border of the bone, and are terminated by two or three smaller teeth in a single row, the last of which again presents the conical form. Each palatine bone supports a double row of teeth, the outer ones being conical and straight, and from four to six in number ; the inner ones two, three, or four in number, and tuberculate. I have seen a specimen where the inner row was wanting on one side. The lower surface of the vomer is covered by a double irregularly alternate series of the same kind of large tuberculate crushing teeth as those at the middle of the premandibular. All the teeth are anchylosed to more or less developed alveolar eminences, like the anterior teeth of the Lophius. The periphery of the expanded circular base of the large anterior grappling teeth is divided into processes indicative of the original ligamentous fasciculi at the base of the pulp by the ossification of which their anchylosis is effected.\nWhen such anchylosed teeth and the supporting bone are divided by a vertical section, as in fig. 2, pi. 66, of my \u201c Odontography,\u201d there may be generally discerned a faint transverse line indicating the original separation between the tooth and the bone,\nand more clearly defining the dental from the osseous structure, than in the anchylosed teeth of other fishes. From the enormous development of the muscles of the jaws, and the strength of the shells of the whelks and other testacea which are cracked and crushed by the teeth, their fracture and displacement must obviously be no unfrequent occurrence ; and most specimens of the jaws of the Wolf-fish exhibit some of the teeth either separated at this line of imperfect anchylosis, or, more rarely, broken off above the base, or, still more rarely, detached by fracture of the supporting osseous alveolar process.\nWith regard to the substance of the teeth of fishes, the modifications of dentine, called vaso-dentine and osteo-dentine *, predominate much more than in the higher Verte-brata ; and they thus more closely resemble the bones which support them. There is, however, great diversity in respect of substance. The teeth of most of the Ch\u00e6to-donts are flexible, elastic, and composed of a yellowish subtransparent albuminous tissue ; such, likewise, are the labial teeth of the He-lostome, the premaxillary and mandibular teeth of the Goniodonts, and of that percoid genus thence called Tnchodon. In the Cy-clostomes the teeth consist of a denser albuminous substance. The upper pharyngeal molar of the Carp consists of a peculiar brown and semitransparent tissue, hardened by salts of lime and magnesia. The teeth of the Flying-fish (Exoc\u0153tus), and Sucking-fish {Remora), consist of osteo-dentine. In many fishes, e.g. the Acanthurus, Sphyr\u0153na, and certain Sharks (Lamna, fig. 545.), a base, or body of osteo-dentine is coated by a layer of true dentine, but of unusual hardness, like enamel: in Prionodon this hard tissue predominates. In the Labrus the pharyngeal crushing teeth consist wholly of hard or unvascular dentine {fig. 544.). In most Pycnodonts and Cestracionts, and many other fishes, the body of the tooth consists of ordinary unvascular dentine, covered by a modification of that tissue which I have called \u201cvitro-dentine\u201d from its clear, polished, enamel-like character : but this is not enamel, nor the product of a distinct organ from the dentinal pulp : it differs from ordinary dentine in the greater proportion of the mineral particles, their more minute diffusion through the gelatinous basis, in the straighter course and more minute size of the calcigerous tribes ; it results from the calcification of the external layer of the dentinal pulp, and is the first part of the tooth which is formed. In Sargus and Batistes the body of the tooth consists of true dentine, and the crown is covered by a thick layer of a denser tissue, developed by a distinct organ, and differing from the \u201c enamel \u201d of higher animals only in the more complicated and organised mode of deposition of the earthy salts. The ossification of the capsule of the complex matrix of these teeth covers the enamel with a thin coating of \u201c cement.\u201d In the pharyngeal\nOdontography, pi. 60, 61.\nOdontography, Introduction, p. lxxii.","page":877},{"file":"p0878.txt","language":"en","ocr_en":"878\nTEETH.\nteeth of the Scarus a fourth s\u00f9bstance is added by the ossification of the base of the pulp after its summit and periphery have been converted into hard dentine ; and the teeth {fig. 558.), thus composed of cement (c), enamel (e), dentine (d), and osteo-dentine, are the most complex in regard to their substance that have yet been discovered in the animal kingdom.\nThe tubes which convey the capillary vessels through the substance of the osteo- and vaso-dentine of the teeth of fishes* were early recognised, on account of their comparatively large size ; as by Andr\u00e9, e.g. in the teeth of Acanthurus, and by Cuvier and Von Born in the teeth of the Wolf-fish and other species. Leeuwenhoek had also detected the much finer tubes of the peripheral dentine of the teeth of the Haddock. These \u201c dentinal tubuli \u201d are given oft' from the parietes of the vascular canals, and bend, divide, and subdivide rapidly in the hard basis-tissue of the interspaces of those canals in osteo-dentine ; the dentinal tubuli alone are found in true dentine, and they have a straighter and more parallel course, usually at right angles to the outer surface of the dentine. Those conical teeth which, when fully formed, consist wholly or in great part of osteo-dentine or vaso-dentine, always first appear with an apex of hard or true dentine. In some fishes the simple central basal pulp-cavity of such teeth, instead of breaking up into irregular or parallel canals, sends out a series of vertical plates from its periphery, which, when calcified, give a fluted character to the base of the tooth, e.g. in Lepidosteus oxyurus.f Sometimes such radiating vertical basal plates of dentine are wavy in their course, and send off\" narrow processes from their sides; and, as a thin layer of the outer capsule interdigi-tates with the outstanding plates of the dentinal pulp, and becomes co-calcified with them, a transverse section of such a tooth presents a series of interblended wavy or labyrinthic tracts of thick dentine radiating from the centre, and of thin cement converging towards the centre of the tooth.J An analogous but more\n* The vaso-dentine of Pristis and Myliobates is like that of the teeth of the Cape Anteater ( Orycte-ropus) : the vaso-dentine of the Psammodonts resembles that which forms the base of the tooth of the Sloth and Megatherium: the vaso-dentine of Mammals differs from the osteo-dentine in the absence of the radiated \u201c Purkinjian\u201d cells.\nf Wyman, American Journal of Natural Sciences, Oct. 1843. Cuvier has given an accurate view of the plaited structure of the base of the Wolf-fish\u2019s teeth in pi. 82, fig. 7. of his Le\u00e7ons d\u2019Anatomie Compar\u00e9e, 1805; where it is described at the base of the osseous tubercle, which supports the true tooth.\nJ This remarkable structure attains its highest complication and forms the largest proportion of the tooth in the gigantic extinct labyrinthodont Batra-chia, and from which, therefore, I have taken the illustrations of that complex modification of dental structure (fig. 552.). I had discovered in 1841 the more simple modification of this structure \u201c at the base of the tooth in a few fishes \u201d (Geol. Trans., 2d series, vol. vi., p. 507), but had not then seen so complex an example in that class as Dr, Wyman\ncomplicated structure obtains when the radiating, wavy, vertical plates of dentine dichotomise, and give off from their sides, throughout their course, numerous branch plates and processes, which are traversed by medullary sinuses and canals with their peripheral terminations dilated, and becoming the centres of lobes or columns of hard dentine. The transverse section of such teeth gives the appearance of branches of a tree, with leaf-stalks and leaves, radiating from the central pulp-cavity to the circumference of the tooth ; and I have called the fossil fish in which this structure was first detected, Dendrodus.\nThus, with reference to the main and fundamental tissue of tooth, we find not fewer than six leading modifications in fishes;\u2014hard or true dentine (Sparoids, Labroids, Lophius, Batistes, Pycnodonts, Prionodon, Spliyr\u0153na, Mega-lichBiys, Rtiizodus, Diodon, Scarus) ; osteo-dentine (Cestracion, Acrodus, Lepidosiren, Ctenodus, Hybodus, Percoids, Scicenoids, Cot-toids, Gobioids, and many others) ; vaso-dentine (Psammodus, Chim\u0153roids, Pristis, Myliobates) ; plici-dentine (Lophius, Holoptychius, Lepidosteus oxyurus, at the base of the teeth) ; labyrintho-dentine (Lepidosteus platyrhinus, Bothriolepis) ; and dendro-dentine (Dendrodus) ; besides the compound teeth of the Scarus and Diodon.\nOne structural modification may prevail in some teeth, another in other teeth of the same fish ; and two or more modifications may be present in the same tooth, arising from changes in the process of calcification and a persistency of portions or processes of the primitive vascular pulp or matrix of the dentine.\nThe dense covering of the beak-like jaws of the Parrot-fishes (Scan), consists of a stratum of prismatic denticles, standing almost vertically to the external surface of the jaw-bone. An account of the structure and development of this peculiar armature of the jaws is abridged from my \u201c Odontography \u201d (pp. 112\u2014116.), in the article Pisces ( Vol. III. p. 979.). It is peculiarly adapted to the habits and exigencies of a tribe of fishes which browse upon the lithophytes that clothe, as with a richly tinted carpet, the bottom of the sea, just as the Ruminant quadrupeds crop the herbage of the dry land.\nThe irritable bodies of the gelatinous polypes which constitute the food of these fishes retract, when touched, into their starshaped stony shells, and the Scari consequently require a dental apparatus strong enough to break off\u2019 or scoop out these calcareous recesses. The jaws are, therefore, prominent, short, and stout, as shown in fig. 515. p. 979. Vol. III.; and the exposed portions of the premaxilliaries and premandibulars are encased by the complicated dental covering represented in figs. 515 and 516. Vol. III.\nThe polypes and their cells are reduced to a pulp by the action of the pharyngeal jaws\nand M. Agassiz (Recherches sur les Poissons Fossiles, \u201c Sauroides,\u201d 1843) subsequently described and figured, in teeth of the genus Lepidosteus.","page":878},{"file":"p0879.txt","language":"en","ocr_en":"TEETH.\nand teeth, that close the posterior aperture of the mouth.\nThe superior dentigerous pharyngeals (Jigs. 558. and 565.) present the form of an elongated, vertical, inequilateral, triangular plate ; the upper and posterior margin is sharp and concave ; the upper and anterior margin forms a thickened articular surface, convex from side to side, and playing in a corresponding groove or concavity upon the base of the skull ; the inferior boundary of the triangle is the longest, and also the broadest ; it is convex in the antero-posterior direction, and flat from side to side. It is on this surface that the teeth are implanted, and in most species they form two rows ; the outer one consisting of very small, the inner one of large dental plates, which are set nearly transversely across the lower surface of the pharyngeal bone, and are in close apposition, one behind the other : their internal angles are produced beyond the margin of the bone, and interlock with those of the adjoining bone when the pharyngeals are in their natural position ; the smaller denticles of the outer row are set in the external interspaces of those of the inner row.\nThe single inferior pharyngeal bone consists principally of an oblong dentigerous plate, of the form represented in fig. 3, pi. 51, of my \u201cOdontography;\u201d its breadth somewhat exceeds that of the conjoined dentigerous surface of the pharyngeals above, and it is excavated to correspond with their convexity. This dentigerous plate is principally supported by a strong, slightly curved, transverse, osseous bar, the extremities of which expand into thick obtuse processes for the implantation of the triturating muscles. A longitudinal crest is continued downwards and forwards from the middle line of the inferior pharyngeal plate, anterior to the transverse bar, to which the protractor muscles are attached.\nA longitudinal row of small oval teeth alternating with the large lamelliform teeth, like those of the superior pharyngeals, bounds the dentigerous plate on each side ; the intermediate space is occupied exclusively by the larger lamelliform or wedge-shaped teeth, set vertically in the bone, and arranged transversely in alternate and pretty close set series.\nThe dental plates are developed in wide and deep cavities in the substance of the posterior part of the lower, and of the anterior part of the upper pharyngeal bones. Each denticle is developed in its proper capsule, which contains an enamel-forming pulp and a dentinal pulp, in close cohesion with each other and with the thin external capsule. The teeth exhibit progressive stages of formation as they approach the posterior part of the upper and the anterior part of the lower pharyngeal bones : as their formation advances to completion they become soldered together by ossification of their respective capsules into one compound tooth, which soon becomes anchylosed by ossification of the dentinal pulp to the pharyngeal bone itself.\nThe dentine of the pharyngeal teeth of the\n879\nScarus consists of calcigerous tubes and a clear intermediate substance. The calcigerous tubes average a diameter of\tof an inch,\nand are separated by interspaces equal to twice their own diameter. The course of these tubes is shown in fig. 558, d., in which they are exposed by a vertical section through the middle of two of the superior denticles. They all, on leaving the pulp-cavity, form a curve with the convexity turned towards the base of the tooth, and then bend slightly in the opposite direction; the sigmoid curve being most marked in the calcigerous tubes at the base of the denticles, whilst those towards the apex become longer and straighter. Besides the primary curvatures exemplified in the figure, each calcigerous tube is minutely undulated ; it dichotomises three or four times near its termination, sends off many fine lateral branches into the clear uniting substance, and finally terminates in a series of minute cells and inosculating loops at the line of junction with the enamel.\nThis substance (fig. 558, e.) is as thick as the dentine, and consists of a similar combination of minute tubes and a clear connecting substance. The tubes may be described as commencing from the pheripheral surface of the tooth to which they stand at right angles, and, having proceeded parallel to each other halfway towards the dentine, they then begin to divide and subdivide, the branches crossing each other obliquely, and finally terminating in the cellular boundary between the enamel and dentine.\nThe teeth which present this complex structure are successively developed at one extremity of the bone, in proportion as they are worn away at the other ; not, however, as Cuvier describes, from behind forwards, in both upper and lower pharyngeal bones, but in opposite directions in the opposite bones, the course of succession being from before backwards in the upper, and from behind forwards in the lower pharyngeal bones. In the progress of the attrition to which they are subjected, the thin coat of cement resulting from the ossification of the capsule is first removed from the apex of the tooth, then the enamel constituting that apex, next the dentine, and, finally, the coarse central cellular bone, supporting the hollow wedge-shaped tooth ; and thus is produced a triturating surface of four different substances of different degrees of density. The enamel, being the densest element, appears in the form of elliptical transverse ridges, inclosing the dentine and central bone ; and external to the enamel is the cement which binds together the different denticles.\nThere is a close analogy between the dental mass of the Scarus and the complicated grinders of the elephant, both in form, structure, and in the reproduction of the component denticles in horizontal succession. But in the fish, the complexity of the triturating surface is greater than in the Mammal, since, from the mode in which the wedge-shaped denticles of the Scarus are implanted upon,","page":879},{"file":"p0880.txt","language":"en","ocr_en":"880\tTEETH.\nand anchylosed to, the processes of the supporting bone, this likewise enters into the formation of the masticatory surface when the tooth is worn down to a certain point.\nThe proof of the efficacy of the complex masticatory apparatus above described is afforded by the contents of the alimentary canal of the Scari. Mr. Charles Darwin, the accomplished naturalist and geologist, who accompanied Captain Fitzroy, R. N., in the circumnavigatory voyage of the \u201c Beagle,\u201d dissected several Parrot-fishes soon after they were caught, and found the intestines laden with nearly pure chalk, such being the nature of their excrements ; whence he ranks these fishes among the geological agents to which is assigned the office of converting the skeletons of the Lithophvtes into chalk.\nDevelopment.\u2014As might have been anticipated from the discovery of the varied and predominating vascular organisation in the teeth of fishes, and the passage from non-vascular dentine to vascular dentine in the same tooth, the true law of the development of dentine \u201cby centripetal metamorphosis and calcification of the cells of the pulp,\u201d was first definitely enunciated and illustrated from observations made on the development of the teeth of fishes.*\nIt is interesting to observe in this class the process arrested at each of the well-marked stages through which the development of a mammalian tooth passes. In all fishes the first step is the simple production of a soft vascular papilla from the free surface of the buccal membrane : in Sharks and Rays these papillae do not proceed to sink into the substance of the gum, but are covered by caps of an opposite free fold of the buccal membrane ; these caps do not contract any organic connection with the papilliform matrix, but, as this is converted into dental tissue, the tooth is gradually withdrawn from the extraneous protecting cap, to take its place and assume the erect position on the margin of the jaw (fig. 510, b, a, art. Pisces, Vol. III. p. 976.). Here, therefore, is represented the first and transitory \u201c papillary \u201d stage of dental development in Mammals ; and the simple crescentic cartilaginous maxillary plate, with the open groove behind containing the germinal papillae of the teeth, offers in the Shark a magnified representation of the earliest condition of the jaws and teeth in the human embryo.\nIn many fishes, e. g. Lophius, Esox, the dental papillae become buried in the membrane from which they rise, and the surface to which their basis is attached becomes the bottom of a closed sac : but this sac does not become inclosed in the substance of the jaw ; so that teeth at different stages of growth are brought away with the thick and soft gum, when it is stripped from the jaw-bone. The final fixation of teeth, so formed, is effected by the\n* In my Hunterian Lectures, delivered at the Royal College of Surgeons, May, 1839. See also, Compte Rendu de l\u2019Academie des Sciences, Dec. 1839, p. 784. ; and Odontography, Introduction, and part i. passim.\ndevelopment of ligamentous fibres in the submucous tissue between the jaw and the base of the tooth, which fibres become the medium of connection between those parts, either as elastic ligaments, or by continuous ossification. Here, therefore, is represented the \u201c follicular \u201d stage of the development of a mammalian tooth ; but the \u201c eruptive \u201d stage takes place without previous inclosure of the follicle and matrix in the substance of the jaw-bone.\nIn Balistes, Searus, Sphyrcena, the Sparoids, and many other fishes, the formation of the teeth presents all the usual stages which have been observed to succeed each other in the dentition of the higher Vertebrata: the papilla sinks into a follicle, becomes surrounded by a capsule, and is then included within a closed alveolus of the growing jaw (Jig. 516. c, Vol. III. p. 979. art. Pisces), where the de-velopement of the tooth takes place and is followed by the usual eruptive stages. A distinct enamel-pulp is developed from the inner surface of the capsule in Balistes, Searus, Sargus, and Chrysophrys.\nThe most formidable dentition exhibited in the order of osseous fishes, is that which characterises the Sphyrcena, and some extinct fishes allied to this predatory genus. In the great Barracuda of the southern shores of the United States (Sphyrcena Bairacuda, Cuv.), the lower jaw contains a single row of large, compressed, conical, sharp-pointed, and sharp-edged teeth, resembling the blades of lancets, but stronger at the base. The two anterior of these teeth are twice as long as the rest, but the posterior and serial teeth gradually increase in size towards the back part of the jaw ; there are about twenty-four of these piercing and cutting teeth in each preman-dibular bone. They are opposed to a double row of similar teeth in the upper jaw, and fit into the interspace of these two rows when the mouth is closed. The outermost row is situated on the intermaxillary, the innermost on the palatine bones ; there are no teeth on the vomer or superior maxillary bones. The two anterior teeth in each premaxillary bone equal the opposite pair in the lower jaw in size : the posterior teeth are serial, numerous, and of small size ; the second of the two anterior large premaxillary teeth is placed on the inner side of the commencement of the row of small teeth, and is a little inclined backwards. The retaining power of all the large anterior teeth is increased by a slight posterior projection, similar to the barb of a fish-hook, but smaller. The palatine bones contain each nine or ten lancet-shaped teeth, somewhat larger than the posterior ones of the lower jaw. All these teeth afford good examples of the mode of attachment by implantation in sockets, which has been denied to exist in fishes.*\nThe loss or injury to which these destructive weapons are liable in the conflict which the Sphyrcena wages with its living and\n* Cuvier, Histoire Naturelle des Poissons, tom. i. p 492.","page":880},{"file":"p0881.txt","language":"en","ocr_en":"TEETH.\n881\nstruggling prey, is repaired by an uninterrupted succession of new pulps and teeth. The existence of these is indicated by the foramina, which are situated immediately posterior to, or on the inner margin of, the sockets of the teeth in place ; these foramina lead to alveoli of reserve, in which the crowns of the new teeth in different stages of development are loosely embedded. It is in this position of the germs of the teeth that the Sphyr\u00e6noid fishes, both recent and fossil, mainly differ, as to their dental characters, from the rest of the Scomberoid family, and proportionally approach the Sauroid type. The base or fang of the fully-developed tooth of the Sphyrcena, is anchylosed to the parietes of the socket in which it is inserted. The pressure of the crown of the new tooth excites absorption of the inner side of the base of the old, which thus finally loses the requisite strength of attachment ; and its loss is followed by the absorption of the old socket, as in the higher animals.\nIt is interesting to observe that the alternate teeth are, in general, contemporaneously shed ; so that the maxillary armour is always preserved in an effective state. The relative position of the new teeth to their predecessors, and their influence upon them, resembles, in the Spki/7'\u0153na, some of the phenomena which will be described in the dentition of the crocodilian reptiles. To the crocodiles the present voracious fish also approximates in the alveolar lodgment of the teeth ; but it manifests its ichthyic character in the anchylosis of the fully-developed teeth to their sockets, and still more strikingly in the intimate structure of the teeth.\nIn all fishes the teeth are shed and renewed, not once only, as in Mammals, but frequently, during the whole course of their lives. The maxillary dental plates of Lepi-dosiren, the cylindrical dental masses of the Chim\u00e6roid and Edaphodont fishes, and the rostral teeth of Pristis (if these modified dermal spines may be so called) are, perhaps, the sole examples of \u201cpermanent teeth\u201d to be met with in the whole class.\nWhen the teeth are developed in alveolar cavities, they are usually succeeded by others in the vertical direction, as in the pharyngeal bones of the Labroids (flg. 513., art. Piscks, Vol. HT. p.978.) ; but sometimes they follow one after the other, side by side, as in the Scaroids (Pisces, fig. 516. c, p.979.). The successional teeth owe the origin of their matrix to the budding out from the capsule of their predecessors of a c\u00e6cal process, in which the papillary rudiment of the dentinal pulp is developed according to the laws explained in the Introduction to my \u201c Odontography,\u201d and the article Tooth. But, in the great majority of fishes, the germs of the new teeth are developed, like those of the old, from the free surface of the buccal membrane throughout the entire period of succession ; a circumstance peculiar to the present class. The Angler, the Pike, and most of our common fishes, illustrate this mode of dental repro-\nVOL. IV.\nduction ; it is very conspicuous in the cartilaginous fishes, in which the whole phalanx of their numerous teeth is ever marching slowly forwards in rotatory progress over the alveolar border of the jaw, the teeth being successively cast off as they reach the outer margin, and new teeth rising from the mucous membrane behind the rear rank of the phalanx.\nThis endless succession and decadence of the teeth, together with the vast numbers in which they often coexist in the same fish, illustrate the law of Vegetative or Irrelative Repetition, as it manifests itself on the first introduction of new organs in the animal kingdom, under which light we must view the above-described organised and calcified preparatory instruments of digestion in the lowest class of the vertebrate series.\nAt the extreme limit of the class of fishes, and connecting that class with the reptiles, stands the very remarkable genus, the dental system of which is figured in cut 560. This consists of two small, slender, conical, sharp-pointed, and slightly recurved teeth, which project downwards from the nasal bone (c), and of strong trenchant dental plates anchylosed with the alveolar border of the upper (a) and lower (b) jaws, in each of which the plate is divided at the middle, or symphysial line, so as to form two distinct lateral teeth.\nThe office of the two laniariform teeth is to pierce and retain the nutritive substance or prey which is afterwards divided and comminuted by the strong maxillary dental plates.\nThe upper pair of these plates is supported by the anterior part of a strong arch of bone, which combines the characters of the superior maxillary, palatine, and pterygoid bones ; the superior maxillary is represented by the median and anterior bar, passing in front of the dental plate of the lower jaw when the mouth is shut, terminating on each side in a process which projects outwards and backwards, as in fig. 560.,\u00ab., on each side of the anterior part of the arch ; the palatine portion constitutes the median part of the roof of the mouth behind the foregoing ; the pterygoid portion is indicated by its fulfilling the usual function of an abutment extended between the palatine portion of the upper j.aw and the articular pedicle of the lower jaw; the upper dental plates are confined to the first two parts of the arch (maxillary and palatine), and do not extend upon the pterygoid portion ; the lower dental plates (b) are anchylosed to the premandibular bone. Viewing the upper pair of plates as a single tooth, it may be described as indented at its outer surface by five vertical angular notches, penetrating inwards through half the breadth of the supporting bone, and dividing the plate into six angular processes, which, from the direction and varying form and breadth of the entering notches, radiate from the posterior part of the median line or division of the tooth. The inferior dental plate is similarly notched on its outer side, but the proportions of the angular indentations are such, that they receive","page":881},{"file":"p0882.txt","language":"en","ocr_en":"882\nTEETH.\nall the processes of the upper dental plate when the mouth is shut, whilst only the four anterior processes are reciprocally received into the notches of the upper dental plate, this, with the supporting arch, being anterior to the lower plate, \u2014 a position which is decisive in favour of its maxillary character, and against its homology with the vomer.\nThe dental plate consists, as in the Cod and Sphyr\u0153na, of a central mass of coarse osseous substance, traversed by large and nearly parallel medullary canals, and an external sheath of very hard \u201c vitro-dentine.\u201d The medullary canals are continued from a coarse reticulation of similar but wider canals in the substance of the supporting bone, and advance forwards, nearly parallel with each other and with the plane of the upper surface of the tooth ; they anastomose together by short, curved, transverse canals, which intercept spaces increasing in length as the canals recede from the osseous basis. The canals themselves diminish in size in the same ratio ; and when they have arrived near the dense outer layer, their divisions and inosculations become again more frequent, the peripheral loops forming a well-marked line of demarcation between the coarse-tubed and the fine-tubed dentine. The interspaces of the medullary canals are occupied by a clear substance, and by moss-like reticulations of fine dentinal tubes, which appear to be more sparing in number than in the teeth of the Sphyr\u0153na or Shark. The dentinal tubes of the vitro-dentine run nearly parallel to each other, and vertically to the external surface of the dental plate through about two-thirds of the thickness of that tissue ; they then bend and cross each other in a manner very similar to those of the vitro-dentine in the teeth of the Lepidotus, Phyllodus, &c.*\nIn the process of attrition this external dense substance is worn away from the upper surface of the dental processes in the lower jaw, exposing the softer vaso-dentinal substance of the tooth ; in this state the dental plate offers an analogy to the incisors of the Rodents, a posterior softer substance being sheathed by an anterior denser layer ; and an external sharp edge is similarly kept up by the unequal wearing away of the two substances. The progressive waste at the upper surface of the dental plate would appear to be met by a corresponding additon of new nmterial to its lower part.\nIn the structure here presented we have a condition of the dentine which has hitherto been met with only in the class of fishes.\nThe test of the affinities of the present paradoxical genus, afforded by the microscopic examination of the teeth, gives additional confirmation to the view to which I have been led, from arguments drawn from the rest of its organisation, that the Lepido-siren is in every essential point a member of the class of fishes.f\n* See Odontography, pp. 70. 166, pi. 59, fig. 4.\nf Linnean Transactions, vol. xviii. 1839. p. 350. That the large size, or elliptical form of its bloocl-\nDental System of Reptiles.\nIf we compare the dental system of the foregoing Batrachoid fish with that in the true Batrachia, it is only to the larval state of the Anourans that an analogy can be found ; the tadpole of the frog having its maxilla and mandibula each sheathed with a single and continuous horny dental trenchant covering. Were this sheath actually dentinal in tissue and united to the jaw-bone, the resemblance to the Lepidosiren would be closer ; but in point of fact the analogy is very remote; the horny beak of the tadpole is never calcified or anchylosed, but is shed during the progress of the metamorphosis.* The Siren alone, among the larval-like pe-rennibranchiate reptiles, retains the sheath upon the extremity of the upper and lower jaws ; it consists of a firm albuminous tissue, and becomes harder than horn. But these trenchant mandibles, which play upon one another like the blades of a pair of curved scissors, are associated with numerous small but distinct true teeth, which are grouped together to form a rasp-like surface on each half of the divided vomer, and which beset the alveolar border of the splenial element of the mandible below.\nIn the class Reptilia, the whole order of Chelonia is edentulous, as well as the whole family of Toads ([Bnfonid\u0153) in the order Batrachia; certain extinct genera of Sau-rians were likewise edentulous, e.g. the remarkable \u201c Rhynchosaurus \u201d of the new red sandstone of Shropshire, and some of the extinct Saurians of South Africa.\nIn the tortoises and turtles the jaws are covered by a sheath of horn, which in some species is of considerable thickness and very dense ; its working surface is trenchant in the carnivorous species, but variously sculptured, and adapted for both cutting and bruising in the vegetable feeders ; it may be said that the transitory condition of the mandibles of the Batrachian larvae is here persistent.\nThe development of the continuous horny maxillary sheath commences, as in the parrot tribe, from a series of distinct papillae, which sink into alveolar cavities, regularly arranged (in Trionyx) along the margins of the upper and lower jaw-bones : these alveoli are indicated by the persistence of vascular canals long after the originally separate tooth-like cones have become confluent, and the horny sheath completed.\nThe teeth of the dentigerous Saurian,\ndiscs should outweigh the cumulative evidence establishing the piscine nature of the Lepidosiren could only be surmised by those who are ignorant of the variation in size and shape which the blood-discs present in the class of fishes, and the consequent unimportance of those particles as a character of the class. As well might the Petromyzon be deemed a mammal because its blood-discs are circular and comparatively small, as the Lepidosiren be held to be a Batrachian because its blood-discs are elliptical and comparatively large.\n* The large dental plates of Lepidosiren have their nearest homologues in those of the extinct fish called Ceratodus (Odontography, pi. 22, fig. 2.).","page":882},{"file":"p0883.txt","language":"en","ocr_en":"TEETH.\n883\nOphidian, and Batrachian reptiles, are, for the most part, simple and adapted for seizing and holding, but not for dividing or masticating their food. The Siren alone combines true teeth with a horny maxillary trenchant sheath, like that of the Chelonian reptiles.\nWith respect to number, in no existing reptile are the teeth reduced so low as in certain mammals and fishes ; nor, on the other hand, are they ever so multiplied as in many of the latter class. The extinct Dicynodont reptiles of South Africa had but two teeth, which were long tusks implanted in the upper jaw.* Some species of Amphisb\u0153na {A. alba), with fifteen teeth in the upper jaw and fourteen in the lower jaw, and certain Monitors ( Varanus), with sixteen teeth in the upper and fourteen in the lower jaw, afford examples of the smallest number of teeth amongst existing reptiles ; and certain Batrachians, with teeth \u201c e9 cardes \u201d at the roof of the mouth, or which have upwards of eighty teeth in each lateral maxillary series, present the largest number. It is rarely that the number of the teeth is fixed and determinate in any reptile so as to be characteristic of the species, and still more rarely have the individual teeth such characters as to be determined homologically from one species to another.\nWith respect to situation, the teeth may be present on the jaws only, i.e. the maxillary, premaxillary, and mandibular bones, as in the crocodiles and many lizards : or upon the jaws and roof of the mouth ; and here either upon the pterygoid bones, as in the Iguana and Mosa-saur, or upon both palatine and pterygoid bones, as in most serpents, or upon the vomer, as in most Batrachians, or upon both vomerine and pterygoid bones, as in the Axo-lote ; or upon the vomerine and sphenoid bones, as in the Salamandre glulinosa, Maclure. With respect to the marginal or jaw teeth, these may be absent in- the intermaxillary bones, as in many serpents ; or they may be present in the upper and not in the lower jaw, as in most frogs ; or in both upper and lower jaws, as in the tailed Batrachians ; and among these they may be supported, upon the lower jaw, by the premandibular or den-tary piece, as in the Salamanders, Menopome, Amphiume, Proteus ; or upon the splenial piece, as in the Siren ; or upon both splenial and premandibular bones, as in the Axolotl. The palatine and pterygoid teeth may, in the Batrachians, be arranged in several rows, like the \u201c dents en cardes \u201d of fishes. The sphenoid and splenial teeth are always so arranged in the few species that possess them. The intermaxillary, maxillary, and premandibular teeth are uniserial, or in one row, with the exception of the C\u00e6cilia and the extinct Labyrinthodonts, which have a double row of teeth at the anterior part of the lower jaw.\nThe teeth of reptiles, with few exceptions, present a simple conical form, with the crown more or less curved, and the apex more or\n* Transactions of the Geological Society, 2d series, vol. vii., 1845, p. 59.\nless acute. The cone varies in length and thickness ; its transverse section is sometimes circular, but more commonly elliptical or oval, and this modification of the cone may be traced through every gradation, from the thick, round, canine-like tooth of the crocodile, to the sabre-shaped fang of the Varanus, the Megalosaur, and the Cladeiodon.* Sometimes, as in the fully formed teeth of the Megalosaur, one of the margins of the compressed crown of the tooth is trenchant, sometimes both are so ; and these may be simply sharp-edged, as in the Varanus of Timor, or finely serrated, as in the great Varanus, the Cladeiodon, and the Megalosaur.f\nThe outer surface of the crown of the tooth is usually smooth ; it may be polished, as in the Leiodon, or impressed with fine lines, as in the Labyrinthodon {fig. 551.), or raised into many narrow ridges, as in the Pleiosaur and Polyptychodon, or broken by a few broad ridges, as in the Iguanodon (fig. 57L), or grooved by a single longitudinal furrow, as in some serpents {fig. 569, A).j;\nThe cone is longest and its summit sharpest in the serpents : from these may be traced, chiefly in the lizard tribe, a progressive shortening,. expansion of the base, and blunting of the apex of the tooth, until the cone is reduced to a hemispherical tubercle, or plate, as in the Thorictes and Cyclodus {fig. 570.).\nIn the Pleiosaur the dental cone is three-sided, with one of the angles rounded off. The posterior subcompressed teeth of the alligator {fig. 573.) present a new modification of form ; here they terminate in a mammillate summit, supported by a slightly constricted neck. In the tooth of the Hyloeosaur the expanded summit is flattened, bent, and spear-shaped, with the edges blunted. But the expansion of the crown is greatest in the subcompressed teeth of the extinct Cardiodon and the existing Iguanas, the teeth of which are farther complicated by having the margins notched. The great Iguanodon had the crown of the tooth expanded both in length and breadth, and combining marginal dentations with longitudinal ridges : this tooth {fig. 57].) presents the most complicated external form as yet discovered in the class of reptiles.\nIn no reptiles does the base of the tooth ever branch into fangs.\nAttachment. \u2014 As a general rule, the teeth of reptiles are anchylosed to the bone which supports them. When they continue distinct, they may be lodged either in a continuous groove, as in the Ichthyosaur $, or in separate sockets, as in the Plesiosaur and Crocodilians {fig. 573.). The base of the tooth is anchylosed to the walls of a moderately deep socket in the extinct Megalosaur and Theocodon. In the Labyrinthodonts and C\u00e6cili\u00e6, among the Bratrachians ; in most Ophidians ; and in the Geckos, Agamians, and Varanians, among the Saurians, the base of the tooth is\n* Odontography, pi. 62 A, fig. 4.\nf lb. fig. 6 c.\nj lb. pi. 65 ; vol. iv., figs. 209, 210,\n\u00a7 lb. pi. 13, fig. 9.","page":883},{"file":"p0884.txt","language":"en","ocr_en":"884\nTEETH.\nimbedded in a shallow socket, and is confluent therewith.\nIn the Scincoidians, the Safeguards ( Tejus), in most Iguanians, in the Chameleons and most other Lacertian reptiles, the tooth is anchylosed by an oblique surface extending from the base more or less upon the outer side of the crown to an external alveolar plate of bone* * * \u00a7, the inner alveolar plate not being developed. In the frogs the teeth are similarly but less firmly attached to an external parapet of bone. The lizards which have their teeth thus attached to the side of the jaw are termed Pleurodonts. In a few Iguanians, as the Istiures, the teeth appear to be soldered to the margins of the jaws, these have been termed \u201c Acrodonts.\u201d In some large extinct Lacertians, e. g. the Mosasaur and Leiodon, the tooth is fixed upon a raised conical process of bone, as shown in my \u201c Odontography,\u201d Plate 68. fig. 1., and Plate 12. fig. 2.\nThese modifications of the attachment of the teeth of reptiles are closely adapted to the destined application of those instruments, and relate to the habits and food of the species ; we may likewise perceive that they offer a close analogy to some of the transitory conditions of the human teeth. There is a period, for example f, when the primitive dental papillae are not defended by either an outer or an inner alveolar process, any more than their calcified homologues which are confluent with the margin of the jaw in the Jlhynehoce{phalus.% There is another stage in which !the groove containing the dental germs is defended by a single external cartilaginous alveolar ridge ; this condition is permanently typified in the Cycbdus (fig. 570.) and most existing lizards. Next there is developed in the human embryo an internal alveolar plate, and the sacs and pulps of the teeth sink into a deep but continuous groove, in which traces of transverse partitions soon make their appearance ; in tire ancient Ichthyosaur the relation of the jaws to the teeth never advanced beyond this stage.\nFinally, the dental groove is divided by complete partitions ||, and a separate socket is formed for each tooth ; and this stage of developement is attained in the highest organised reptiles, e.g. the crocodiles (fig. 573.).\nSubstance. \u2014 This may be four-fold, and a single tooth may be composed of dentine, cement, enamel, and bone; but the dentine and cement are present in the teeth of all reptiles.\nIn the Batrachians and Ophidians a thin layer of cement invests the central body of dentine, and, as usual, follows any inflections or sinuosities that may characterise\n* Odontography, pi. 67.\nf At the sixth week of gestation : see Prof. Good-sir, \u201c On the Development of the Human Teeth,\u201d Edinburgh Medical and Surgical Journal, No. 138.\nJ See Geological Transactions, 2d series, vol. vii. pt. 2, pi. 6, figs. 5 & 6, p. 83.\n\u00a7 At the seventh or eighth week : Ibid.\nII At the sixth month : Ibid.\nthe dentine. Besides the outer coat of cement, which is thickest at the base of the teeth, a generally thin coat of enamel defends the crown of the tooth in most Saurians, and the last remains of the pulp are not unfrequently converted into a coarse bone, both in the teeth which are anchylosed to the jaw, and in some teeth, as those of the Ichthyosaur, which remain free. The only modification of the dentine, which could at all entitle it to be regarded in the light of a new or distinct substance, is that which is peculiar in the present class to the teeth of the Iguanodon, and which will be described in the following section.\nStructure. \u2014 The varieties of dental structure are few in the reptiles as compared with either fishes or mammals, and its most complicated condition arises from interblending of the dentinal and other substances rather than from modifications of the tissues themselves. In the teeth of most reptiles the intimate structure of the dentine corresponds with that which has been described as the type of the tissue, e.g. the hard or unvascular dentine, and which is the prevailing modification in Mammalia, viz., the radiation of a system of minute plasmatic tubes from a single pulp-cavity, at right angles to the external surface of the tooth. The most essential modification of this structure is the intermingling of cylindrical processes of the pulp-cavity in the form of medullary canals, with the finer tubular structure.* Another modification is that in which the dentine maintains its normal structure, but is folded inwardly upon itself, so as to produce a deep longitudinal indentation on one side of the tooth ; it is the expansion of the bottom of such a longitudinal deep fold that forms the central canal of the venom-fang of the serpent ; but a glance at fig. 568. will show that, notwithstanding the singularly modified disposition of the dentine (5), its structure remains unaltered ; and although the pulp-cavity (p) is reduced to the form of a crescentic fissure, the dentinal tubes continue to radiate from it according to the usual law. By a similar inflection of many vertical longitudinal folds of the external cement and external surface of the tooth at regular intervals around the entire circumference of the tooth, and by a corresponding extension of radiated processes of the pulp-cavity and dentine into the interspaces of such inflected and converging folds, a modification of dental structure is established in certain extinct reptiles, which, by the various sinuosities of the inter-blended folds of cement and processes of dentine, with the partial dilatations of the radiated pulp-cavity, produces the complicated structure which is described at p. 868. and figured in cut 552. But this complication is nevertheless referable to a modification of form or arrangement of the dental tissues, rather than of the structure of the tissues themselves : the calcigerous tubes in each sinuous lobe of dentine, in the most\nOdontography, pi. 71, Iguanodon.","page":884},{"file":"p0885.txt","language":"en","ocr_en":"TEETH.\n885\ncomplex tooth of the Labyrinthodon, exhibit the same general disposition and course as in the fang of the serpent and in the still more simple tooth of the Saurian.\njDevelopment.\u2014The teeth of reptiles are never completed, as in certain fishes, at the first or papillary stage ; but the pulp sinks into a follicle, and becomes inclosed by a capsule; and in certain reptiles this becomes more or less surrounded by bone ; but the process of development never offers the eruptive stage, in the sense in which this is usually understood, as signifying the extrication of the young tooth from a closed alveolus.\nThe completion of a tooth, with the extinct exception of the Dicynodont Reptiles, is soon followed by preparation for its removal and succession : the faculty of developing new tooth-germs seems to be unlimited in the present class, and the phenomena of dental decadence and replacement are manifested at every period of life; the number of teeth is generally the same in each successive series, and the difference of size presented by the teeth of different and distant series is considerable.\nThe new germ is always developed, in the first instance, at the side of the base of the old tooth, never in the cavity of the base ; the crocodiles form no exception to this rule. The poison-fangs of serpents succeed each other from behind forwards ; in almost every other instance the germ of the successional tooth is developed at the inner side of the base of its predecessor. In the frog the dental germ makes its appearance in the form of a papilla developed from the bottom and towards the outer side of a small fissure in the mucous membrane or gum that fills up the shallow groove at the inner side of the alveolar parapet and its adherent teeth: the papilla is soon enveloped by a capsular process of the surrounding membrane : there is a small enamel pulp developed from the capsule opposite the apex of the tooth ; the deposition of the earthy salts in this mould is accompanied by ossification of the capsule, which afterwards proceeds pari passu with the calcification of the dentinal papilla or pulp ; so that, with the exception of its base, the surface of the uncalcified part of the pulp alone remains normally unadherent to the capsule.\nAs the tooth acquires hardness and size, it presses against the base of the contiguous attached tooth, causes a progressive absorption of that part, and finally undermines, displaces, and replaces its predecessor. The number of nascent matrices of the successional teeth is so great in the frog, and they are crowded so close together, that it is not unusual to find the capsules of contiguous tooth-germs becoming adherent together, as their ossification proceeds. After a brief maceration, the soft gum may be stripped from the shallow alveolar depression, and the younger tooth-germs in different stages of growth are brought away with it.\nThe mode of development of the teeth of serpents does not differ essentially from that\nof the teeth of the Batrachian above described except in the relation of the papillae of the successional poison-fangs to the branch of the poison-duct that traverses the cavity of the loose mucous gum in which they are developed.\nBatrachian modifications.\u2014 Some of the peculiarities of the dentition of the Batrachians have already been noticed, as in the comparison of the Siren with the Lepidosiren, in which the true amphibian was shown to have numerous teeth on the palate and lower jaw.*\nThe piscine character of rasp-like teeth aggregated in numerous series, is manifested also in the Axolotl f, upon the palatal region of the mouth, and upon the splenial or opercular element of the lower jaw ; but the superior maxillary bones are here developed, and also support teeth. The premandibular and the premaxillary bones, instead of preserving the larval condition of the horny sheath, have their alveolar border armed with a single row of small, equal, fine and sharp-pointed denticles, which are continued above, along the maxillaries; thus establishing the commencement of the ordinary Batrachian condition of the marginal teeth of the buccal cavity. The dentigerous bones of the palate consist of two plates on each side, as in the Siren ; the anterior pair, or vomerine bones, converge and meet at their anterior extremities ; the minute denticles which they support are arranged quincuncially ; the posterior pair of bones are continued backwards according to the usual disposition of the pterygoids, to abut against the tympanic bones ; the denticles are confined to the anterior part of their oral surface, and resemble in their arrangement and anchylosed attachment those of the vomerine series, of which they form the posterior termination.\nThe frogs (Rana) J have no teeth on the lower jaw ; but in some species the alveolar edge of this bone is finely notched or dentated, as in the horned frogs (Ceratophrys). The intermaxillary and maxillary bones support a long, close-set, single series of small, conical, hollow teeth, of which the apices only project beyond the external alveolar ridge to which they are attached. A short transverse row of similar but smaller teeth extends along the posterior border of each vomer, except in the slender-armed frogs (Leptobrachium), and in some of the tree frogs (e. g. Euchnemis), in which the roof of the mouth is edentulous.\nAmongst the most extraordinary examples of extinct reptiles are those which are characterised by the labyrinthic modification of the dental structure above described, and which with some affinities to Saurians, combine characters which are essentially those of the order Batrachia. I have ascertained by fossil portions of the upper jaw of the Labyrinthodon leptognathus that the maxillary or facial division of the skull was broad, much depressed, and flattened, resembling the skull of the\n* Odontography, pi. 62, figs. 5 & 6 t lb. pi. 62, fig. 4. t lb. pi. 62, fig. 10.\n3 L 3","page":885},{"file":"p0886.txt","language":"en","ocr_en":"886\nTEETH.\ngigantic Salamander and of the Alligator ; and the outer surface of the bones was strongly sculptured, as in the Crocodilian family, but of a relatively larger and coarser pattern. The upper jaw contains a single row of small teeth, about sixty in number, anterior to which are three or four large conical tusks. The bases of the serial teeth project directly from the outer wall of the shallow socket, there being no alveolar ridge external to it. The second large anterior tusk is three times the size of the first of the serial teeth, and the size of these teeth gradually diminishes as they are placed further back ; the length of the common-sized teeth being about two lines, and the greatest breadth one-third of a line. The apical two-thirds of each tooth is smooth, but the basal third is fluted and anchylosed to the outer wall of the socket. The osseous roof of the mouth is principally composed of a pair of broad and flat bones, homologous with the divided vomer in Batrachia, but of much greater relative extent, approaching, in this respect, those of the Menopome, and defending the mouth with a more extensive roof of bone than exists in any Lacertian reptile ; physiologically, therefore, the Labyrinthodon, in this part of its structure, comes nearest to the Crocodile ; but the structure itself, morphologically, is essentially Batrachian.* In the Menopome-}- and gigantic Salamander, a row of small teeth extends transversely across the anterior extremity of the vomerine bones ; and the occurrence in the Labyrinthodon of a similar row, consisting in each palatine bone of three median small teeth and two outer larger ones, marks most strongly its Batrachian nature ; and from the outermost tooth a longitudinal row of small and equal-sized teeth is continued backward along the exterior margin of the palatine bone. The whole of this series of palatal teeth is nearly concentric with the maxillary teeth.\nIn Lacertine reptiles the examples of a row of palatal teeth are rare, and, when present, it is short, and situated towards the back of the palate, upon the pterygoid bones, as in the Iguana and Mosasaur.j; In Batra-chians the most common disposition of the palatal teeth is a transverse row placed at the anterior part of the divided vomer, as in Frogs, the Menopome and gigantic Salamander, and at the posterior part in certain toads. In the Amphiume, on the contrary, the palatal teeth form a nearly longitudinal series along the outer margin of the palatine bones. The Labyrinthodon combines both these dispositions of the palatal teeth. The lower jaw, like the upper, contains a series of small teeth, with a few larger tusks anterior to them, the serial teeth are long and slender, gradually diminishing in size towards the anterior portion of the jaw ; the largest fossil portion which I have obtained presents a linear series of not less than fifty sockets, placed alter-\n* Odontography, pi. 63. A, fig. 3.\nf lb. pi. 62. figs. 1 & 2.\nX lb. pi. 68.\nnately, one nearer the inner, the next nearer the outer side of the jaw. The sockets of the teeth are shallower than in the upper jaw ; the outer wall is more developed than the inner, and the anchylosed bases of the teeth more nearly resemble, in their oblique position, those of existing Batrachia. With regard to the modification of the microscopic structure of the teeth, I may observe that, between the apex and the part where the inflected vertical folds of the cement commence, the tooth resembles, in the simplicity of its intimate structure, that of the entire tooth of ordinary Batrachia and most reptiles ; and in the lower or basal half of the tooth the labyrinthic structure above described commences, and gradually increases in complexity.\nIn the genus JDeirodon*, the teeth of the ordinary bones of the mouth are so small as to be scarcely perceptible ; and they appear to be soon lost, so that it has been described as edentulous, and has been called \u201c Anodon.\u201d An acquaintance with the habits and food of this species has shown how admirably this apparent defect is adapted to its wellbeing. Its business is to restrain the undue increase of the smaller birds by devouring their eggs. Now if the teeth had existed of the ordinary form and proportions in the maxillary and palatal regions, the egg would have been broken as soon as it was seized, and much of the nutritious contents would have escaped from the lipless mouth of the snake in the act of deglutition ; but, owing to the almost edentulous state of the jaws, the egg glides along the expanded opening unbroken ; and it is not until it has reached the gullet, and the closed mouth prevents any escape of the nutritious matter, that the egg becomes exposed to instruments adapted for its perforation. These instruments consist of the inferior spinous pocessess (hyp-apophyses) of the seven or eight posterior cervical vertebrae, the extremities of which are capped by a layer of hard cement, and penetrate the dorsal parietes of the oesophagus. They may be readily seen, even in very small subjects, in the interior of that tube, in which their points are directed backwards. The shell being sawed open longitudinally by these vertebral teeth, the egg is crushed by the contractions of the gullet, and is carried to the stomach, where the shell is no doubt soon dissolved by the acid gastric juice.\nIn the Boa Constrictor, the teeth are slender, conical, suddenly bent backwards and inwards above their base of attachment ; the crown is straight or very slightly curved, e. g. in the posterior teeth. The intermaxillary bone supports four small teeth ; each maxillary bone has eight much larger ones, which gradually decrease in size as they are placed further back. There are eight or nine teeth of similar size and proportions in each premandibular bone. These teeth\n* The Coluber scaber of Linn\u00e6us ; an arboreal serpent of South Africa.","page":886},{"file":"p0887.txt","language":"en","ocr_en":"887\nTEETH.\nare separated by wide intervals, from which other teeth, similar to those in place, have been detached. The base of each of the above teeth is extended transversely, compressed antero-posteriorly, and anchylosed to a shallow alveolus, extending obliquely across the shallower alveolar groove. An affinity to the lizard tribes is manifested by the greater development of the outer, as compared with the inner wall of the alveolar furrow.\nThe palatine teeth, of which there are three or four in each palatal bone, are as large as the superior maxillary, and are similarly attached. The pterygoid teeth, five or six in number, which complete the internal dental series on the roof of the mouth, are of smaller size, and gradually diminish as they recede backwards. In the interspaces of the fixed teeth in both these bones, the places of attachment of the shed teeth are always visible ; so that the dental formula, if it included the vacated with the occupied sockets, would express a greater number of teeth than are ever in place and use at the same time.* In the smaller species of Boa, the intermaxillary bone is edentulous.\nThe Colubers, like other true serpents, have two longitudinal rows of teeth on the roof of the mouth, extending along the palatines and pterygoids. The genus Oligodon appears to form the sole exception to this rule. In the Dryinus nasutus, a few small teeth are present on the ecto-pterygoid as well as on the pterygoid.\nIn certain genera of non-poisonous serpents, as Dryophis, Dipsas, and Bucephalus, in which the superior maxillary teeth increase in size towards the posterior part of the bone, the large terminal teeth of the series are traversed along their anterior and convex side by a longitudinal groove. In the Bucephalus capensis, the two or three posterior maxillary teeth present this structure, and are much larger than the anterior teeth, or those of the palatine and premandibular series. They add materially, therefore, to the power of retaining the prey, and may conduct into the wounds which they inflict an acrid saliva ; but they are not in connection with the duet of an express poison-gland. The long-grooved fangs are either firmly fixed to the maxillary bones, or are slightly moveable, according to their period of growth. They are concealed by a sheath of thick and soft gum, and their points are directed backwards. The sheath always contains loose recumbent grooved teeth, ready to succeed those in place.\nIn most of the Colubri, each maxillary and premandibular bone includes from twenty to twenty-five teeth. They are less numerous in the genera Tortrix and Homalopsis, and are reduced to a still smaller number in the poisonous serpents, in the typical genera of which the short maxillary bone supports only a single perforated fang.\nPoisonous Serpents. \u2014 The transition to these serpents, which was begun in the Bucepha/i and allied genera with grooved maxillary teeth, is completed by the poisonous serpents of the genera Pelamis, Hydrophis, Elaps, Bongarus, and Hamadryas.\nThe superior maxillary bone diminishes in length with the decreasing number of teeth which it supports. The ecto-pterygoid bone elongates in the same ratio, so as to retain its position as an abutment against the shortened maxillary, and the muscles implanted into this external pterygoid bone communicate through it to the maxillary bone the hinge-like movements backwards and forwards upon the ginglymoid articulations connecting that bone with the prefrontal and palatine bones. As the fuliy-developed poison-fangs are attached by the same firm basal anchylosis to maxillary sockets, which forms the characteristic mode of attachment of the simple or solid teeth, they necessarily follow all the movements of the superior maxillary bone. When the external pterygoid is retracted, the superior maxillary rotates backwards, and the poison-fang is concealed in the lax mucous gum, with its point turned backwards. When the muscles draw forward the external pterygoid, the superior maxillary bone is pushed forwards, and the recumbent fang withdrawn from its concealment and erected.\nIn this power of changing the direction of a large tooth, so that it may not impede the passage of food through the mouth, we may perceive an analogy between the viper and the Lophius; but in the fish the movement is confined to the tooth alone, and is dependent on the mere physical property of the elastic medium of attachment ; in the serpent the tooth has no independent motion, but rotates wdth the jaw, whose movements are governed by muscular actions. In the fish the great teeth are erect, except when pressed down by some extraneous force. In the serpent the habitual position of the fang is the recumbent one, and its erection takes place only when the envenomed blow is to be struck.\nA true idea of the structure of a poison-fang will be formed by supposing the crown of a simple tooth, as that of a boa, to be pressed flat, and its edges to be then bent towards each other, and soldered together so as to form a hollow cylinder, or rather cone, open at both ends. The flattening of the fang and its inflection around the poison-duct commences immediately above the base, and the suture of the inflected margins runs along the anterior and convex side of the recurved fang, as shown in fig. 567, a. : the poison-canal is thus in front of the pulp-cavity, as shown in the longitudinal section of the fang b. The basal aperture of the poison-canal v is oblique, and its opposite outlet v' is still more so, presenting the form of a narrow elliptical longitudinal fissure terminating at a short distance from the apex of the fang. The relative position of the two apertures of the poison-canal is shown in the figure of\nOdontography, pi. 65, figs. 6 & 7.","page":887},{"file":"p0888.txt","language":"en","ocr_en":"888\tTEETH.\nthe fang of the large Cobra in my \u201c Odonto- longitudinal indentation on the convex side giaphy (pi. 65.fig. 9., and in Vol. IV. p. 290. of the fang; as it proceeds it sinks deeper fig. 210., art. Reptilia), where a fine hair is into the substance of the tooth, and the sides represented as passing through the poison- of the groove meet and seem to coalesce, so canal.\tthat\ttrace of the inflected fold ceases,\nThe poison-glands occupy the sides of the in some species, to be perceptible to the posterior half of the head ; each gland con- naked eye ; and the fang appears, as it is sists of a number of elongated narrow lobes, commonly described, to be perforated by the extending from the main duct, which runs duct of the poison-gland. In the Hydrophis along the lower border of the gland upwards the groove remains permanently open, as in and slightly backwards: each lobe gives off fig 567. c.\nlobules throughout its extent, thus presenting From the real nature of the poison-canal a pinnatifid structure; and each lobule is it follows that the transverse section of the subdivided into smaller secerning caeca, which tooth varies in form in different parts of the constitute the ultimate structure of the gland, tooth ; at the base it is oblong, with a large Ihe whole gland is surrounded by a double pulp-cavity of a corresponding form, with an aponeurotic capsule, of which the outermost entering notch at the anterior surface ; farther and strongest layer is in connection with the on the transverse section presents the form muscles by whose contraction the several caeca of a horse-shoe, and the pulp-cavity that of and lobes of the gland are compressed and a crescent, the horns of which extend into emptied of their secretion. This is then con- the sides of the deep cavity of the poison-veyed by the duct (see Reptilia, Vol. IV. fang : a little beyond this part the section of p. 291., fig. 211. e) to the basal aperture of the the tooth itself is crescentic, with the horns poison-canal of the fangj\u00a3 We may suppose, obtuse and in contact, so as to circumscribe that as the analogous lachrymal and salivary the poison-canal ; and along the whole of glands in other animals are most active during the middle four-sixths of the tooth, the section, particular emotions, so the rage which stimu- of which a magnified view is given in fig. 568., lates the venom-snake to use its deadly weapon\nmust be accompanied with an increased secre-\tFig. 568.\ntion and great distension of the poison-glands ; and as the action of the compressing muscles is contemporaneous with the blow by which the serpent inflicts the wound, the poison is at the same moment injected with force into the wound from the apical outlet of the perforated fang.\nThe duct which conveys the poison, although it runs through the centre of a great part of the tooth, is really on the outside of the tooth, the canal in which it is lodged and protected being formed by a longitudinal inflection of the dentinal parietes of the pulp-cavity. This inflection com-\nSection of poison-fang of Serpent. (Magnified.)\nshows the dentine of the fang inclosing the poison-canal, and having its own centre or pulp-canal (p,p), in the form of a crescentic fissure, situated close to the concave border of the inflected surface of the tooth, The pulp-cavity disappears, and the poison-canal again resumes the form of a groove near the apex of the fang, and terminates on the anterior surface in an elongated fissure.\nThe venom-fangs of the viper, rattle-snake, and the Fer-de-lance are coated only with a thin layer of a subtransparent and minutely cellular cement. The disposition of the dentinal tubes is obedient to the general law of verticality to the external surface of the tooth ; it is represented as seen in the transverse sec-mences a little beyond the base of the tooth, tion from the middle of the fang in^\u00eeg. 568. where its nature is readily appreciated, as the Since the inflected surface of the tooth can poison-duct there rests in a slight groove or be exposed to no other pressure than that of\nFig. 567.\nA\tB\nPoison-fangs of Serpents. {Magnified.')","page":888},{"file":"p0889.txt","language":"en","ocr_en":"TEETH.\t889\nthe turgescent duct with which it is in con- surface of the pulp ; and the base of the tact, the tubes which proceed to the surface groove of the loose, growing, poison-fang is d, while maintaining their normal relation of brought into the same relation with the duct the right angle to it, are extremely short ; and of the poison gland as the displaced fang, the layer of dentine separating the poison- which has been severed from the duct, tube from the pulp-cavity is proportionally Saurians. \u2014 The existing species of lizards thin. The calcigerous tubes that radiate from differ from those of the crocodile in the anchy-the opposite side of the pulp-cavity to the losed condition of the teeth, which present few exposed surface b of the tooth are dispropor- modifications of importance ; those that yield tionally long.\tmost fruit to physiology, and which have most\nThe teeth of Ophidians are developed and expanded our ideas of the extent of the recompleted in that part which forms the ori- sources of Nature and the exceptional devi-ginal seat of the tooth-germs in all animals ; ations from what was deemed the rule of viz. the mucous membrane or gum covering, structure in the Saurian dentition, have been the alveolar border of the dentigerous bones, discovered by the study of the fossil teeth of This germ presents the same lax tissue, and extinct forms of the order. Amongst these the is as abundantly developed, as in the Pike, most extraordinary in respect of their dental Lophius, and many other fishes; in which it system have been recently discovered in aform-likewise serves as the nidus and locality for ation in South Africa, which seems nearly as the complete development of the teeth. The ancient as our own coal-seams. I have called primitive dental papillae in the common harm- them \u201c Dicynodonts,\u201d* from their dentition less snake very soon sinks into the substance being reduced to one long and large canine of the gum, and becomes inclosed by a cap- tooth on each side of the upper jaw. As sule. As soon as the deposition of the cal- these teeth give, at first sight, a character to careous salts commences in the apex of the the jaws like that which the long poison-fangs papilla the capsule covering that part becomes give, when erected, to the jaws of the rattle-ossified and adherent to the dentine, and the snake, I shall briefly notice their characters tooth begins to pierce and emerge from the before entering upon the description of the gum before its mould, the pulp, is half com- more normal Saurian dentition, pleted. Fresh layers of cells are successively Fig. 569. gives a reduced side view of the added to the base of the pulp, and converted, skull of the species of Dicynodon called D. la-by their confluence and calcification, into the certiceps. The cranial cavity (8,8) is extremely tubular dentine, until the full size of the contracted, as in all the cold-blooded quad-tooth is attained, when its situation in the rupeds : it is bounded on each side by wide gum is gradually changed, and its base becomes and deep temporal fossae ([t) indicating power-\nFig. 569.\nSkull of Dicynodon lacerticeps, one-third natural size.\nanchylosed to the shallow cavity of the alveolar surface of the bone.\nIn the posterior part of the large mucous sheath of the poison-fang, the successors of this tooth are always to be found in different stages of development ; the pulp is at first a simple papilla, and when it has sunk into the gum the succeeding portion presents a depression along its inferior surface, as it lies horizontally, with the apex directed backwards; the capsule adheres to this inflected\nful muscles for the action of the lower jaw. The orbits (o) are large and round ; the nostrils (n) are divided by the junction of the nasal bones (15) with the premaxillaries (22), as in lizards ; there is not a single median external nostril, as in Chelonian and Crocodilian reptiles. The alveolar border of the lower jaw and of the premaxillary part of the\n* From S/V, two, and xwidovf, the name given by Hippocrates to the canine teeth, and signifying thie same idea as their common English denomination.","page":889},{"file":"p0890.txt","language":"en","ocr_en":"890\tTEETH.\nupper jaw is trenchant, and seems to have been sheathed with horn.\nThe maxillary bone (21) is excavated by a wide and deep alveolus, with a circular area of half an inch, and lodges a long and strong, slightly curved, and sharp-pointed, canine tooth or tusk, which projects about two-thirds of its length from the open extremity of the socket. The direction of the tusks is forwards, downwards, and very slightly inwards ; the two converging, as they descend along the outer side of the compressed symphysis of the lower jaw (c). The tusk is principally composed of a body of compact unvascular dentine. The base is excavated by a wide conical pulp-cavity (p) with the apex extending to about one-half of the implanted part of the tusk, and a linear tract is continued along the centre of the solid part of the tusk. From this central line the dentinal tubes radiate, with a gentle curve at the beginning, convex towards the point of the tusk, and then proceeding straight to the periphery of the tooth, but inclining towards the apex. They present parallel secondary curves, divide di-chotomously twice or thrice near their beginning, and send off numerous small lateral branches, chiefly from the side next the apex. At their primary curve the dentinal tubes are __i._g.th of an inch in diameter, and their intervals are g^rth an across* The dentinal cells are most conspicuous near the periphery of the tooth, and vary in diameter from -g-Lg-th to T-^\u00f6\u00f6th of an inch.\nThe enamel, at least at the middle of the tusk, is thinner than in the teeth of the crocodile. It presents only a finely lamellated texture, the layers being parallel with the surface of the dentine on which it rests. There is only a fine linear trace of cement on the exterior of the sections of the implanted base of the tusks ; and here it is too thin to allow of the development of the radiated cells in its substance. There is no trace of teeth or their sockets in the lower jaw (25, 23) ; so much of the alveolar border as is exposed presents a smooth and even edge, which seems to have played like a scissor-blade upon the inner side of the corresponding edentulous border of the upper jaw ; and it is most probable, from the analogies of similarly-shaped jaws of existing Reptilia, that the fore part of both the upper and under jaws were sheathed with horn.\nUntil the discovery of the Rhynchosaurus*, this edentulous and horn-sheathed condition of the jaws was supposed to be peculiar to the Chelonian order among reptiles ; and it is not one of the least interesting features of the Dicynodonts of the African sandstones, that they should repeat a Chelonian character, hitherto peculiar, amongst Lacertians, to the above-cited remarkable extinct edentulous genus of the new red sandstone of Shropshire : but our interest rises almost to astonishment, when, in a Saurian skull, we find, superadded to the horn-clad mandibles\n* Transactions of the Cambridge Philosophical Society, vol. vii. part iii.\nof the Tortoise, a pair of tusks, borrowed as it were from the mammalian class, or rather foreshadowing a structure which, in the actual creation, is peculiar to certain members of the highest organised warm-blooded animals.\nIn the other Reptilia, recent or extinct, which most nearly approach the Mammalia in the structure of their teeth, the difference characteristic of the inferior and cold-blooded class is manifested in the shape, and in the system of shedding and succession, of the teeth : the base of the implanted teeth seldom becomes consolidated, never contracted to a point, as in the fangs of the simple teeth of Mammalia, and at all periods of growth one or more germs of teeth are formed within or near the base of the tooth in use, prepared to succeed it, and progressing towards its displacement. The dental armature of the jaws is kept in serviceable order by uninterrupted change and succession ; but the matrix of the individual tooth is soon exhausted, and the life of the tooth itself may be said to be comparatively short.\nThe Dicynodonts not only manifest the higher type of free implantation of the base of the tooth in a deep and complete socket, common to Crocodilians, Megalosaurs, and Thecodonts, but make an additional and much more important step towards the mammalian type of dentition, by maintaining the serviceable state of the tusk by virtue of constant renovation of the substance of one and the same matrix, accordingly to the principle manifested in the long-lived and ever-growing tusks of the Walrus, and the scalpriform incisors of the Rodentia.\nThe genera of the typical family of the squamate Lacertians are arranged in two sub-families, the chief characteristics of which are derived from the dental system.\nIn the first group, the teeth are solid, or without any permanent internal cavity, and are very firmly anchylosed by their base to the alveolar groove upon the inner side of the jaw ; so that the extremity of the tooth is slightly directed outwards. The species which present this character are called Pleo-donts.\nIn the second group, the teeth are excavated, or retain the pulp-cavity, and are less firmly fixed to the jaws, being applied vertically, like piles or buttresses, against the outer alveolar parapet, but not adhering by their base. This group is called C\u0153lodonts.\nThe Monitor Lizard of S. America is an example of the Pleodont group, in which the premaxillary teeth are ten in number. The maxillary teeth vary from ten to fifteen on each side, and increase in size as they are placed farther back : the hindmost teeth are tricuspid in young individuals, and present the form of simple tubercles in the old Monitors. The mandibular teeth, fifteen to eighteen in number in each ramus, correspond in size and form with those above. In the C\u0153lodont group, the \u201c Swift lizards\u201d (Tacky-dromns) have the pterygoid bones armed with minute teeth. The teeth on both upper and","page":890},{"file":"p0891.txt","language":"en","ocr_en":"TEETH.\n891\nlower jaws are of larger size, and the hinder ones are tricuspid. The true lizards (La-certa) have two kinds of teeth quoad form ; the anterior small, conical, and recurved ; the posterior larger, and bi- or tri-cuspid. Some species have also pterygoid teeth; as the common Lacerta agilis.\nIn the Gigantic fossil Monitor of Maes-tricht, the teeth combine the Pleodont with the Acrodont* characters.\nThe true affinities of the Mosasaur, which was at least twenty-four feet in length, and the remains of which characterise the chalk-formations, were first determined by Cuvier, who places it in the Lacertian group of Saurians, between the Iguan\u00e6 and Monitors. Its dentition exhibits in an eminent degree the Acrodont character ; the teeth being supported on expanded conical bases anchylosed to the summit of the alveolar ridge of the jaw : no existing Saurian exactly parallels this mode of attachment of the teeth, either in regard to the breadth of the alveolar border, or in the relative size of the osseous cones to the teeth which they support. A shallow socket is left where the tooth and its supporting base are shed. The form of the teeth is likewise different from that hitherto observed in any existing Saurian : the crown is pyramidal, with the outer side nearly plane, or slightly convex, and separated by two sharp ridges from the remaining surface, which forms a half-cone. All the teeth\naccount of the Mosasaurus, \u201c has no true root, but it adheres strongly to that pulp which has secreted it, and it is further held in connection with it by the remains of the capsule which has furnished the enamel, and which, by becoming ossified also, and uniting itself to the maxillary bone and the ossified pulp, implants or rivets the tooth with additional force.\u201d\nThe necessity under which Cuvier felt himself compelled to regard the crown and the base of the tooth of the Mosasaur as two distinct parts, is at once banished by the recognition of the principle, that the processes of calcification are essentially the same at every part of a tooth, whether it be free or anchylosed ; and that they are modified only, as 1 have shown in my Memoir on the Formation of the Teeth of the Shark*, according to the density of the part to be produced.\nScincoid Lizards.\u2014Most of these smooth-scaled lizards have small mouths and slender sharp teeth, fitted best for insect food ; they are usually confined to the upper and lower jaws ; but the medicinal Scink of ancient pharmacy (Scincus officinalis) has four or five small obtuse teeth upon each pterygoid bone. The chief exception to the typical dentition of the present family is made by the large scincoid lizards of Australia, which, on that account, have received the generic name of Cyclodus. f\nFig. 570.\nLower jaw and teeth of Cyclodus nigroluteus.\nare slightly recurved, and their peripheral surface is smooth. The teeth are implanted upon the premaxillary, maxillary, and pre-mandibulary bones ; a series of similarly shaped but much smaller teeth are placed upon the pterygoid bones.\nThe gradual transition from the simple structure of the compact dentine to the osteo-dentine of the anchylosed base of the tooth was not known to Cuvier; otherwise he could not have supposed that the crown and the base of the tooth of the Mosasaurus were formed by vital processes of so dissimilar a nature as to forbid him considering them as parts of one and the same body. Cuvier had originally described the expanded base of the tooth of the Mosasaur as the root of the tooth ; but afterwards, observing that the corresponding base became anchylosed by ossification of the remains of the pulp to the jaw, he conceived it to be incorrect to regard it as a part of a body which he believed to be an inorganic product, and the result of excretion. \u201c The tooth,\u201d he observes, in correcting his first\n* Odontography, pp. 241. 258.\nThe dentition of the Cycl. nigroluteus is exemplified in the lower jaw, fig. 570. In the upper jaw, the single premaxillary bone has depressions for twelve teeth, of which only the alternate ones are usually in place ; they are of very small size, with the fang compressed laterally, and the crown antero-posteriorly, so as to resemble a true incisor in form, the summit sloping to an edge from behind forwards, with the middle of the cutting surface a little produced. Each superior maxillary bone has depressions for fourteen teeth ; they quickly increase in size, and exchange their conical for a sub-hemispherical crown; the eighth to the thirteenth inclusive are the largest teeth ; they are set obliquely, and pretty close together. In the lower jaw there are two small incisors, at the anterior part of each premandibular bone corresponding with those of the premaxillary ; these are succeeded by five or six conical teeth, and the rest correspond in size and form with the tuberculate molars of the upper jaw.\n* Compte Rendu de l\u2019Acad\u00e9mie des Sciences, D\u00e9cembre, 1839.\n\\ Round-toothed : xvxXo;, round ; otiov;, tooth.","page":891},{"file":"p0892.txt","language":"en","ocr_en":"892\nTEETH.\nAll the teeth are attached, after the Pleuro-dont type, by their base and outer margin to shallow depressions on the outer side of the external alveolar parapet.\nThe germs of the successional teeth, c. fig. 570., are developed at the inner side of the base of their predecessors, a, which they excavate, undermine, and displace in the usual manner.\nIguanas.\u2014Certain genera of this family of lizards, e. g. Istiurus, Lophyrus, Calotes, and Otocryptis, have the teeth soldered, like those of Mosasaurus, to the summit of the alveolar ridge, and thence are called \u201c Acrodonts : \u201d in all these lizards the maxillary and mandibular teeth may be divided into anterior laniary, and posterior molary teeth. In most of the Iguanians the teeth are lodged in a common shallow oblique alveolar groove, and are soldered to excavations on the inner surface of the outer wall of the groove : these are called Pleurodonts. Most of them possess pterygoid as well as maxillary teeth ; but the following genera, Hyperanodon, Tropido-lepis, Phrynosoma, and Callisaurus, are exceptions.\nIn the Pleurodont Iguanians, the teeth never present the true laniary form ; and if simply conical, as at the extremes of the maxillary series, the cone is more or less obtuse ; but, in general, it is expanded, more or less trilobate, or dentated along the margin of the crown.\nThe Amblyrhynchus, a genus which is somewhat remarkable for the marine habits of at least one of the species (Amblyrhynchus ater), whose diet is sea-weed*, has the tricuspid structure well developed in the posterior teeth.\nThe typical genus of the present family of Saurians (Iguana tuberculala), is characterised by the crenate or dentated margin of the crown of the maxillary and premandibular teeth, a few of the anterior small ones excepted. The pterygoid teeth are arranged in two or three irregular rows, resembling somewhat the \u201c dents en cardes \u201d of fishes. In the full-grown Iguana tuberculata there are from forty-seven to forty-nine teeth in both upper and lower jaws. The number is less in young subjects. The double row of pterygoid teeth are in close order on each side.\nIn the horned Iguana (Metopoceros cor-nutus), there are about fifty-six teeth in the upper and lower jaws, of which the four first are conical and slightly recurved. The twelve succeeding teeth are somewhat larger in size, with more compressed and expanded crowns ; the rest are triangular, compressed, with dentated margins. The inner surface of the crown of the tooth is simply convex and\n* This species, and probably all the known Am-blyrhynchi, or blunt-nosed Iguana?, inhabit the islands in the Galopagos group ; their habits have been well elucidated by Mr. Darwin (Voyage of the Beagle, vol. iii. p. 466.). In specimens which he dissected, he found the stomach loaded with minced sea-weed.\nsmooth ; the outer surface traversed by a median, longitudinal, broad, obtuse ridge. There is a single row of small teeth implanted in each pterygoid bone. No Iguanian lizard has teeth on the palatine bones.\nThe teeth of the Iguanodon, though resembling those of the Iguana, do not present an exact magnified image of them, but differ in the greater relative thickness of the crown, its more complicated external surface, and, still more essentially, in a modification of the internal structure, by which the Iguanodon equally deviates from every other known reptile.\nAs in the Iguana, the base of the tooth is elongated, contracted, and subcylindrical ; the crown expanded, and smoothly convex on the inner side. When first formed, it is acuminated, compressed, its sloping sides serrated, and its external surface traversed by a median longitudinal ridge, and coated by a layer of enamel, but, beyond this point, the description of the tooth of the Iguanodon indicates characters peculiar to that genus. In most of the teeth that have hitherto been\nFig. 571.\nUnworn tooth of Iguanodon.\nfound, three longitudinal ridges (fig. 571.) traverse the outer surface of the crown, one on each side of the median primitive ridge ; these are separated from each other, and from the serrated margins of the crown, by four wide and smooth longitudinal grooves. The relative width of these grooves varies in different teeth ; sometimes a fourth small longitudinal ridge is developed on the outer side of the crown. The marginal serrations, which, at first sight, appear to be simple notches, as in the Iguana, present, under a low magnifying power, the form of transverse ridges, themselves notched, so as to resemble the mammilated margins of the unworn plates of the elephant\u2019s grinder : slight grooves lead from the interspaces of these notches upon the sides of the marginal ridges. These ridges, or dentations, do not extend beyond the expanded part of the crown : the longitudinal ridges are continued further down, especially the median ones, which do not subside till the fang of the tooth begins to assume its subcjlindrical form. The tooth at first increases both in breadth and thickness ; it then diminishes in breadth, but its thickness goes on increasing ; in the larger and fully formed teeth, the fang de-","page":892},{"file":"p0893.txt","language":"en","ocr_en":"TEETH.\ncreases in every diameter, and sometimes tapers almost to a point. The smooth unbroken surface of such fangs indicates that they did not adhere to the inner side of the maxillae, as in the Iguana, but were placed in separate alveoli, as in the Crocodile and Megalosaur ; such support would appear, indeed, to be indispensable to teeth so worn by mastication as those of the Iguanodon. A fracture of this tooth shows that the pulp was not entirely solidified, but that its cavity had continued open at the thickest part of the tooth.\nThe apex of the tooth soon begins to be worn away, and it would appear, by many specimens that have been found, that the teeth were retained until nearly the whole of the crown had yielded to the daily abrasion. In these teeth, however, the deep excavation of the remaining fang, represented in profile in the figure fig. 571., plainly bespeaks the progress of the successional tooth prepared to supply the place of the worn-out grinder.\nAt the earlier stages of abrasion, a sharp edge is maintained at the external part of the tooth by means of the enamel which covers that surface of the crown. The prominent ridges upon that surface give a sinuous contour to the middle of the cutting edge, whilst its sides are jagged by the lateral serrations. The adaptation of this admirable dental instrument to the cropping and comminution of such tough vegetable food as the Clathrari\u00e6 and similar plants, which are found buried with the Iguanodon, is pointed out by Dr. Buckland, with his usual felicity of illustration, in his \u201cBridgewater Treatise,\u201d vol. i. p. 246.\nWhen the crown is worn away beyond the enamel, it presents a broad and nearly horizontal grinding surface, and now another dental substance is brought into use to give an inequality to that surface ; this is the ossified remnant of the pulp, which, being firmer than the surrounding dentine, forms a slight transverse ridge in the middle of the grinding surface. The tooth in this stage has exchanged the functions of an incisor for that of a molar, and is prepared to give the final compression, or comminution, to the coarsely divided vegetable matters.\nThe marginal edge of the incisive condition of the tooth and the median ridge of the molar stage are more effectually established by the introduction of a modification into the texture of the dentine, by which it is rendered softer than in the existing Iguan\u00e6 and other reptiles, and more easily worn away : this is effected by an arrest of the calcifying process along certain cylindrical tracts of the pulp, which is thus continued, in the form of medullary canals, analogous to those in the soft dentine of the Megatherium\u2019s grinder, from the central cavity, at pretty regular intervals, parallel with the calcigerous tubes, nearly to the surface of the tooth. The medullary canals radiate from the internal and lateral sides of the pulp-cavity, and are confined to the dentine forming the corre-\n893\nsponding walls of the tooth; their diameter is \u2022j^pth of an inch ; they are separated by pretty regular intervals, equal to from six to eight of their own diameters ; they sometimes divide once in their course. Each medullary canal is surrounded by a clear substance ; its cavity was occupied in the section described by a substance of a deeper yellow colour than the rest of the dentine.\nThe calcigerous tubes present a diameter of\n\u2018KMoth of an inch, with interspaces equal to about four of their diameters. At the first part of their course, near the pulp-cavity, they are bent in strong undulations, but afterwards proceed in slight and regular primary curves, or in nearly straight lines, to the periphery of the tooth. When viewed in a longitudinal section of the tooth, the concavity of the primary curvature is turned towards the base of the tooth ; the lowest tubes are inclined towards the root, the rest have a general direction at right angles to the axis of the tooth ; the few calcigerous tubes, which proceed vertically to the apex, are soon worn away, and can be seen only in a section of the apical part of the crown of an incompletely developed tooth. The secondary undulations of each tooth are regular and very minute. The branches, both primary and secondary, of the calcigerous tubes are sent off from the concave side of the main inflections ; the minute secondary branches are remarkable at certain parts of the tooth for their flexuous ramifications, anastomoses, and dilatations into minute calcigerous cells, which take place along nearly parallel lines for a limited extent of the course of the main tubes. The appearance of interruption in the course of the calcigerous tubes, occasioned by this modification of their secondary branches, is represented by the irregularly dotted tracts in the figure of the dental structure of this ancient reptile given in my \u201c Odontography.\u201d This modification must contribute, with the medullary canals, though in a minor degree, in producing that inequality of texture and of density in the dentine, which renders the broad and thick tooth of the Iguanodon more efficient as a triturating instrument.\nThe enamel which invests the harder dentine, forming the outer side of the tooth, presents the same peculiar dirty brown colour, when viewed by transmitted light, as in most other teeth : very minute and scarcely perceptible undulating fibres, running vertically to the surface of the tooth, is the only structure I have been able to detect in it.\nThe cement is simply and minutely cellular upon the crown of the tooth, but it exhibits the radiated cells at the base of the tooth.\nThe remains of the pulp in the contracted cavity of the completely formed tooth are converted into a dense but true osseous substance, characterised by minute elliptical radiated cells, whose long axis is parallel with the plane of the concentric lamellae, which surround the few and contracted medullary canals in this substance.","page":893},{"file":"p0894.txt","language":"en","ocr_en":"894\nTEETH.\nThe microscopical examination of the structure of the Iguanodon\u2019s teeth thus contributes additional evidence of the perfection of their adaptation to the offices to which their more obvious characters had indicated them to have been destined.\nTo preserve a trenchant edge, a partial coating of enamel is applied ; and, that the thick body of the tooth might be worn away in a more regularly oblique plane, the dentine is rendered softer as it recedes from the enameled edge by the simple contrivance of arresting the calcifying process along certain tracts of the inner wall of the tooth. When attrition has at length exhausted the enamel and the tooth is limited to its functions as a grinder, a third substance has been prepared in the ossified remnant of the pulp to add to the efficiency of the dental instrument in its final capacity. And if the following reflections were natural and just after a review of the external characters of the dental organs of the Iguanodon, their truth and beauty become still more manifest as our knowledge of their subject becomes more particular and exact :\n\u201c In this curious piece of animal mechanism we find a varied adjustment of all parts and proportions of the tooth, to the exercise of peculiar functions, attended by compensations adapted to shifting conditions of the instrument, during different stages of its consumption. And we must estimate the works of nature by a different standard from that which we apply to the productions of human art, if we can view such examples of mechanical contrivance, united with so much economy of expenditure, and with such anticipated adaptations to varying conditions in their application, without feeling a profound conviction that all this adjustment has resulted from design and high intelligence.\u201d *\nVaranians.\u2014 In the great Crocodilian Monitor ( Varanvs crocodilinus), the large fixed compressed teeth, of which there may be about seven in each upper maxillary bone and six in each premandibular, are anchylosed by the whole of their base and by an oblique surface leading upwards on the outer side of the tooth to a slight depression on the oblique alveolar surface, as in the Var. striatus. The base of the tooth is finely striated, the lines being produced by inflected folds of the external cement, as in the Ichthyosaur and Labyrinthodon, but they are short and straight, as in those of the former genus. The alveolar channel or groove has scarcely any depth; but the anchylosed base of the tooth is applied to an oblique surface, terminating in a sharp edge, from which the outer side of the free crown of the tooth is directly continued. The great Varanus, like the variegated species manifests its affinity to the Crocodilians in the number of successive teeth which are in progress of growth to replace each other ; but from the position in which the germs of the successional teeth are developed, the more\n* Buckland\u2019s Bridgewater Treatise, vol. i. p. 249.\nadvanced teeth in this species, as in the Var. varicgatus, do not exhibit the excavations that characterise the same parts of the teeth of the Enaliosaurs and Crocodiles.\nThecodonts. \u2014 We have seen that among the inferior or squamate Saurians there are two leading modifications in the mode of attachment of the teeth, the base of which may be either anchylosed to the summit of an alveolar ridge, or to the bottom of an alveolar groove, and supported by its lateral wall. These modifications are indicated respectively by the terms \u201c Acrodont \u201d and \u201c Pleurodont.\u201d A third mode of fixation is presented by some extinct Saurians, which, in other parts of their organisation, adhere to the squamate or Lacertine division of the order, the teeth being implanted in sockets, either loosely or confluent with the bony walls of the cavity ; these I have termed the \u201c Thecodont\u201d* La-certians ; the most ancient of all Saurians belong to this group ; viz. the Thuringian Monitor, or Protorosaurus, and the Pal\u0153o-saurns of the dolomitic conglomerates near Bristol. The compressed Varanian form of tooth, with trenchant and finely dentated margins, which characterised the ancient Pa-loeosaur and Chadeiodon, is continued in the comparatively more recent and gigantic species of terrestrial lizard, of which the remains were discovered by Dr. Buckland in the oolite of Stonesfield, by whom the peculiarities of the jaws and teeth have been accurately and graphically described in the following words : \u2014\n\u201c From these remains we learn that the animal was a reptile, closely allied to some of our modern lizards ; and viewing the teeth as instruments for providing food to a carnivorous creature of enormous magnitude, they appear to have been admirably adapted to the destructive office for which they have been designed. Their form and mechanism will be best explained by reference to the figures.\n\u201c The outer margin of the jaw rises nearly an inch above its inner margin, forming a continuous lateral parapet to support the teeth on the exterior side, where the greatest support was necessary, whilst the inner margin throws up a series of triangular plates of bone forming a zigzag buttress along the interior of the alveoli. From the centre of each triangular plate, a bony partition crosses to the outer parapet, thus completing the successive alveoli. The new teeth are seen in the angle between each triangular plate, rising in reserve to supply the loss of older teeth, as often as progressive growth, or accidental fracture, may render such renewal necessarj-, and thus affording an exuberant provision for a rapid succession and restoration of these most essential implements. They were formed in distinct cavities, by the side of the old teeth, towards the interior surface of the jaw, and probably expelled them by the usual process of pressure and absorption, insinuating themselves into the cavities thus left vacant. This contrivance\n* Odontography, partii. p. 266.","page":894},{"file":"p0895.txt","language":"en","ocr_en":"TEETH.\n893\nfor the renewal of teeth is strictly analogous to that which takes place in the dentition of many species of existing lizards.\n\u201c In the structure of these teeth we find a combination of mechanical contrivances analogous to those which are adopted in the construction of the knife, the sabre, and the saw. When first protruded above the gum, the apex of each tooth presented a double cutting edge of serrated enamel. In this stage, its position and line of action were nearly vertical, and its form, like that of the two-edged point of a sabre, cutting equally on each side. As the tooth advanced in growth it became curved backwards in the form of a pruning-knife, and the edge of serrated enamel was continued downwards to the base of the inner and cutting side of the tooth, whilst on the outer side a similar edge descended but a short distance from the point, and the convex portion of the tooth became blunt and thick, as the back of a knife is made thick for the purpose of producing strength. The strength of the tooth was further increased by the expansion of its side. Had the serrature continued along the whole of the blunt and convex portion of the tooth, it would in this position have possessed no useful cutting power ; it ceased precisely at the point beyond which it could no longer be effective. In a tooth thus formed for cutting along its concave edge, each movement of the jaw combined the power of the knife and saw ; whilst the apex, in making the first incision, acted like the two-edged point of a sabre. The backward curvature of the full-grown teeth enabled them to retain, like barbs, the prey which they had penetrated. In these adaptations we see contrivances which human ingenuity has also adopted in the preparation of various instruments of art.\u201d *\nThe teeth of the Megalosaur consist of a central body of dentine, with an investment of enamel upon the crown, and of cement over all, but thickest upon the fang. The marginal serrations are formed almost entirely by the enamel, and when slightly magnified are seen to be rounded, and separated by slight basal grooves ; the smooth and polished enamel upon the sides of the crown presents a finely wrinkled appearance; the remains of the pulp are converted into a coarse bone in the completely formed tooth.\njEnaliosaurs. \u2014 The teeth of the Ichthyosauri have a simple, more or less acutely conical form, with a long and, usually, expanded or ventricose base, or implanted fang. They are confined to the intermaxillary, maxillary, and premandibular bones, in which they are arranged in a pretty close and uninterrupted series, and are of nearly equal size. They consist of a body of unvascular dentine, invested at the base by a thick layer of cement, and at the crown by a layer of enamel, which is itself covered by a very thin coat of cement; the pulp-cavity is more or\n* Bridgewater Treatise, vol. i. p. 287.\nless occupied in fully-formed teeth by a coarse bone. The external surface of the tooth is marked by the longitudinal impressions and ridges, but the teeth vary both as to outward sculpturing and general form in the different species*\nThe chief peculiarity of the dental system of the Ichthyosaur is the mode of the implantation of the teeth ; instead of being an-chylosed to the bottom and side of a continuous shallow groove, as in most Lacertians, or implanted in distinct sockets, as in the The-codon, Megalosaur, or Pt\u00e9rodactyle, they are lodged loosely in a long and deep continuous furrow, and retained by slight ridges between the teeth, along the sides and bottom of the furrow, and by the gum and organised membranes continued into the groove and upon the base of the teeth.\nThe germs of the new teeth are developed at the inner side of the base of the old ones.\nCrocodilia. \u2014 The best and most readily recognisable characters by which the existing Crocodilians are grouped in appropriate genera, are derived from modifications of the dental system.\nIn the Caimans (genus Alligator) the teeth\nvary in number from jg^jg to g9\u201422 : the\nfourth tooth of the lower jaw, or canine, is received into a cavity of the palatal surface of the upper jaw, where it is concealed when the mouth is shut. In old individuals the upper jaw is perforated by these large inferior canines, and the fossae are converted into foramina.\nIn the Crocodiles (genus Crocodilus) the first tooth in the lower jaw perforates the palatal process of the premaxillary bone when the mouth is closed ; the fourth tooth in the lower jaw is received into a notch excavated in the side of the alveolar border of the upper jaw, and is visible externally when the mouth is closed.\nIn the two preceding genera the alveolar borders of the jaw have an uneven or wavy contour, and the teeth are of an unequal size.\nIn the Gavials (genus Gavialis) the teeth are nearly equal in size and similar in form in both jaws, and the first as well as the fourth tooth in the lower jaw, passes into a groove in the margin of the upper jaw when the mouth is closed.\nIn the alligators and crocodiles the teeth are more unequal in size, and less regular in arrangement, and more diversified in form than in the Gavials : witness the strong thick conical laniary teeth as contrasted with the blunt maramiliate summits of the posterior teeth in the alligator (Jig. 573.). The teeth of the Gavial are subequal, most of them present the form of crown, shown in Jig. 572., long, slender, pointed, subcompressed from before backwards, with a trenchant edge on the right and left sides, between which a few faint longitudinal ridges traverse the basal part of the enamelled crown.\n* Odontography, pi. 73.","page":895},{"file":"p0896.txt","language":"en","ocr_en":"896\nTEETH.\nFig. 572.\nTeeth in different stages of formation from one alveolus of the Gavial: a is the base partly absorbed by the pressure of b, the successional tooth ; below which is figured c, the germ of the next tooth to follow.\nAmongst the remains of Crocodilians which are scattered through the Tilgate strata, the most common ones are detached teeth, from the difference observable in the form of which, Dr. Mantell has observed, that \u201c they appear referable to two kinds, the one belonging to that division of crocodiles with long slender muzzles, named Gavial, the other to a species of Crocodile, properly so-called, and resembling a fossil species found at Caen.\u201d*\nDr. Mantell has obligingly communicated to me figures of well-preserved specimens of both the forms of teeth alluded to, the exactness of which I have recognised by a comparison with the specimens themselves in the British Museum.\nThe tooth which, from its more slender and acuminated form, approaches nearest to the character of those of the Gavial, presents a marked difference, however, from the teeth of any of the recent species of that sub-genus of Crocodilians, as well as from those of the long and slender-snouted extinct genera, called Teleosaurus, Steneosaurus, &c. I have described itj\", therefore, as indicative of a distinct species, under the name of Crocodilus cidtridens. The crown is laterally compressed, subincurved, with two opposite trenchant edges, one forming the concave, the other the convex, outline of the tooth. In the Gavial, the direction of the flattening of the crown and the situation of the trenchant edges are the reverse, the compression being from before backwards, and the edges being lateral.%\n* Wonders of Geology, 1839, vol. i. p. 386.\n+ Odontography, pi. lxii. a, figs. 9, 10. t The tooth attributed by M. Deslongchamps to the Poikilopleuron, agrees in form with those of\nThe tooth of the Crocodilus cidtridens thus resembles in form that of the Megalosaur, and perhaps still more those of the Argenton crocodile ; but I have not observed any specimens of the Wealden teeth in which the edges of the crown were serrated, as in both the reptiles just cited. The teeth of the Crocodilus cidtridens also present a character which does not exist in the teeth of the Megalosaur, and is not attributed by Cuvier to those of the Crocodile d'Argenton. The sides of the crown are traversed by a few longitudinal parallel ridges, with regular intervals of about one line, in a crown of a tooth one inch and a half in length : these ridges subside before they reach the apex of the tooth, and more rapidly at the convex than at the concave side of the crown.\nHitherto these teeth have not been found so associated with any part of the skeleton of the same species as to yield further characters of the present extinct Crocodilian ; but from the above-mentioned well-marked differences between these teeth and those of all the existing species, it is most probable that the extinct crocodile formed the type of a distinct sub-genus, for which the term Su-chosaurus has been proposed.\nThe second form of tooth having the generic characters of those of the crocodile, which has been discovered in the Wealden and approximate strata, is as remarkable for its thick, rounded, and obtuse crown as the teeth of the preceding species are for their slender, compressed, acute, and trenchant character. It consequently approaches more nearly to the teeth which characterise the broad and comparatively short-snouted crocodiles ; but it differs from these in one of the same characters by which the tooth of the Suchosaurus cultridens differs from those of the Gavials, viz., in the longitudinal ridges which traverse the exterior of the crown. These are, however, more numerous, more close-set, and more neatly defined than in the Suchosaurus cultridens. Two of the ridges, larger and sharper than the rest, traverse opposite sides of the tooth, from the base to the apex of the crown ; they are placed, as in the crocodile and Gavial, at the sides of the crown, midway between the convex and concave lines of the curvature of the tooth. These ridges are confined to the enamel ; the cement-covered cylindrical base of the tooth is smooth. The size of the teeth varies from a length of crown of two inches, with a basal diameter of one inch and a half to teeth of one-third of these dimensions. I have proposed to call this extinct crocodile, with biconcave vertebrae, Goniopholis crassidens.\nDevelopment. \u2014 In the black alligator of Guiana the first fourteen teeth of the lower jaw are implanted in distinct sockets, the remaining posterior teeth are lodged close together in a continuous groove, in which the divisions for sockets are faintly indicated by vertical ridges, as in the jaws of the Ichthyo-\nthe Gavial, and differs in the characters cited in the text from those of the Crocodilus cultridens.","page":896},{"file":"p0897.txt","language":"en","ocr_en":"TEETH.\n897\nsaurs. A thin compact floor of bone separates this groove, and the sockets anterior to it, from the large cavity of the ramus of the jaw ; it is pierced by bloodvessels for the supply of the pulps of the growing teeth and the vascular dentiparous membrane which lines the alveolar cavities.\nThe tooth-germ is developed from the membrane covering the angle between the floor and the inner wall of the socket. It becomes in this situation completely enveloped by its capsule, and an enamel-organ is formed at the inner surface of the capsule before the young tooth penetrates the interior of the pulp-cavity of its predecessor.\nThe matrix of the young growing tooth affects, by its pressure, the inner wall of the socket, as shown in fig. 573, and forms for\nFig. 573.\nSection of lower jaw, with four alveoli and teeth, of the black Alligator.\nitself a shallow recess : at the same time it attacks the side of the base of the contained tooth ; then, gaining a more extensive attachment by its basis and increased size, it penetrates the large pulp-cavity of the previously formed tooth either by a circular or semicircular perforation. The size of the calcified part of the tooth-matrix which has produced the corresponding absorption of the previously formed tooth on the one side, and of the alveolar process on the other, is represented in the second exposed alveolus of fig. 573., the tooth a having been displaced and turned round to show the effects of the stimulus of the pressure. The size of the perforation in the tooth, and of the depression in the jaw, proves them to have been, in great part, caused by the soft matrix, which must have produced its effect by exciting vital action of the absorbents, and not by mere mechanical force. The resistance of the wall of the pulp-cavity having been thus overcome, the growing tooth and its matrix recede from the temporary alveolar depression, and sink into the substance of the pulp contained in the\nVOL. IV.\ncavity of the fully-formed tooth. As the new tooth grows, the pulp of the old one is removed ; the old tooth itself is next attacked, and the crown being undermined by the absorption of the inner surface of its base, may be broken off by a slight external force, when the point of the new tooth is exposed, as in the j%. 573. h.\nThe new tooth disembarrasses itself of the cylindrical base of its predecessor, with which it is sheathed, by maintaining the excitement of the absorbent process so long as the cement of the old fang retains any vital connection with the periosteum of the socket ; but the frail remains of the old cylinder, thus reduced, are sometimes lifted off the socket upon the crown of the new tooth, as in fig. 573. h, when they are speedily removed by the action of the jaws. This is, however, the only part of the process which is immediately produced by mechanical force : an attentive observation of the more important previous stages of growth, teaches that the pressure of the growing tooth operates upon the one to be displaced only through the medium of the vital absorbent action which it has excited.\nMost of the stages in the development and succession of the teeth of the crocodiles are described by Cuvier with bis wonted clearness and accuracy ; but the mechanical explanation of the expulsion of the old tooth, which Cuvier adopts from M. Tenon, is opposed by the disproportionate smallness of the hard part of the new tooth to the vacuity in the old one, and by the fact that the matter impressing\u2014 viz. the uncalcified part of the walls of the tooth-matrix \u2014 is less dense than the part impressed.\nNo sooner has the young tooth penetrated the interior of the old one, than another germ begins to be developed from the angle between the base of the young tooth and the inner alveolar process, or in the same relative position as that in which its immediate predecessor began to rise, and the processes of succession and displacement are carried on, uninterruptedly, throughout the long life of these cold-blooded carnivorous reptiles.\nFrom the period of exclusion from the egg, the teeth of the crocodile succeed each other in the vertical direction ; none are added from behind forwards, like the true molars in Mammalia. It follows, therefore, that the number of the teeth of the crocodile is as great when it first sees the light as when it has acquired its full size; and, owing to the rapidity of the succession, the cavity at the base of the fully-formed tooth is never consolidated.\nThe fossil jaws of the extinct Crocodilians demonstrate that the same law regulated the succession of the teeth, at the ancient epochs when those highly organised reptiles prevailed in greatest numbers, and under the most varied generic and specific modifications, as at the present period, when they are reduced to a single family, composed of so few and slightly varied species as to have constituted","page":897},{"file":"p0898.txt","language":"en","ocr_en":"898\nTEETH.\nin the system of Linnaeus a small fraction of his genus Lacerta.\nDental System of Mammals.\nThe class Mammalia, like that of Beptilia and Pisces, includes a few genera and species that are devoid of teeth : the true ant-eaters (Myrmecophaga), the scaly ant-eaters or Pangolins (Mams), and the spiny monotrematous ant-eater (Echidna), are examples of strictly edentulous Mammals. The Ornithorhynchus has horny teeth, and the whales (Bal\u00e6na and Balcenoptera) have transitory embryonic calcified teeth*, succeeded by whalebone substitutes j~ in the upper jaw. Horny processes analogous to, perhaps homologous with, the lingual and palatal teeth in fishes, are present in the Echidna.\nThe female Narwhal seems to be edentulous, but has the germs of two tusks in the substance of the upper jaw-bones; one of these becomes developed into a large and conspicuous weapon in the male Narwhal, and, accordingly, suggested to Linn\u00e6us the name, for its genus, of Monodon, meaning single tooth : but the tusk is never median, like the truly single tooth on the palate of the Myxine ; and occasionally both tusks are developed in the Narwhal. In another Cetacean, the great Bottle-nose, or Hyperoodon, the teeth are reduced in the adult to two in number, whence the specific name H. bidens, but they are confined to the lower jaw. The sharp-nosed dolphin (Ziphius) has also but two teeth, one in each ramus of the lower jaw ; and this is, perhaps, a sexual character. The Delphinus griseus has five teeth on each side of the lower jaw ; but they soon become reduced to two. Amongst the marsupial animals, the genus Tarsipes is remarkable for the paucity as well as minuteness of its teeth.\nThe elephant has never more than one entire molar, or parts of two, in use on each side of the upper and lower jaws ; to which are added two tusks, more or less developed, in the upper jaw.\nSome Rodents, as the Australian Water-rats (Hydromys), have two grinders on each side of both jaws ; which, added to the four cutting teeth in front, make twelve in all : the common number of teeth in this order is twenty ; but the hares and rabbits have twenty-eight teeth. The sloth has eighteen teeth. The number of teeth, thirty-two, which characterises man, the apes of the old world, and the true ruminants, is the average one of the class Mammalia ; but the typical number is forty-four.\nThe examples of excessive number of teeth are presented, in the order Bruta, by the Priodont Armadillo, which has ninety-eight teeth ; and, in the cetaceous order, by the Cachalot, which has upwards of sixty teeth, though most of them are confined to the lower jaw ; by the common porpoise, which has between eighty and ninety teeth ; by the\n* Odontography, pi. 87 a, figs. 1\u20146.\nf lb. pi. 76, figs. 4. 6 ; art. Cetacea, Yol. I. p. 572, fig. 259 b.\nGangetic dolphin, which has one hundred and twenty teeth ; and by the true dolphins (Delphinus), which have from one hundred to one hundred and ninety teeth, yielding the maximum number in the class Mammalia.\nForm.\u2014Where the teeth are in excessive number, as in the species above cited, they are small, equal, or subequal, and of a simple conical form ; pointed, and slightly recurved in the common dolphin ; with a broad and flattened base in the gangetic dolphin (Inia) ; with the crown compressed, and broadest in the porpoise ; compressed but truncate, and equal with the fang, in the Priodon. The compressed triangular teeth become coarsely notched or dentated, at the hinder part of the series, in the great extinct cetaceous Zeu-glodon. The simple dentition of the smaller Armadillos, of the Orycterope, and of the three-toed Sloth, presents a difference in the size, but little variety in the shape of the teeth, which are subcylindrical, with broad triturating surfaces ; in the two-toed Sloth, the two anterior teeth of the upper jaw are longer and larger than the rest, and adapted for piercing and tearing.\nIn almost all the other Mammalia, particular teeth have special forms for special uses : thus, the front teeth, from being commonly adapted to effect the first coarse division of the food, have been called cutters or incisors ; and the back teeth, which complete its comminution, grinders or molars ; large conical teeth, situated behind the incisors, and adapted by being nearer the insertion of the biting muscles, to act with greater force, are called holders, tearers, laniaries, or more commonly canine teeth, from being well developed in the dog and other Carnivora, although they are given, likewise, to many vegetable feeders for defence or combat : e. g. Musk-deer (Jig. 580, VII.). Molar teeth, which are adapted for mastication, have either tuberculate, or ridged, or flat, summits ; and usually are either surrounded by a fence of enamel, or are traversed by enamel plates arranged in various patterns. Certain molars in the Dugong, the Mylodon, and the Zeuglodon, are so deeply indented laterally by opposite longitudinal grooves, as to appear, when abraded, to be composed of two cylindrical teeth cemented together, and the transverse section of the crown is bilobed. The teeth of the Glyptodon were fluted by two analogous grooves on each side. The large molars of the Capybara and Elephant have the crown cleft into a numerous series of compressed transverse plates, cemented together side by side.\nThe teeth of the Mammalia have usually so much more definite and complex a form than those of fishes and reptiles, that three parts are recognised in them : viz. the \u201c fang,\u201d the \u201cneck,\u201d and the \u201ccrown.\u201d The fang or root (radix) is the inserted part ; the crown (corona) the exposed part ; and the construction which divides these is called the neck (cervix). The term \u201c fang \u201d is properly given only to the implanted part of a tooth of re-","page":898},{"file":"p0899.txt","language":"en","ocr_en":"TEETH.\nstrieted growth, which fang gradually tapers to its extremity ; those teeth which grow uninterruptedly have not their exposed part separated by a neck from their implanted part, and this generally maintains to its extremity the same shape and size as the exposed crown,\nIt is peculiar to the class Mammalia to have teeth implanted in sockets by two or more fangs ; but this can only happen to teeth of limited growth, and generally characterises the molars and premolars ; perpetually growing teeth require the base to be kept simple and widely excavated for the persistent pulp. In no mammiferous animal does anchylosis of the tooth with the jaw constitute a normal mode of attachment. Each tooth has its particular socket, to which it firmly adheres by the close co-adaptation of their opposed surfaces, and by the firm adhesion of the alveolar periosteum to the organised cement which invests the fang or fangs of the tooth ; but in some of the Cetacea, at the posterior part of the dental series, the sockets are wide and shallow, and the teeth adhere more strongly to the gum than to the periosteum ; in the Cachalot I have seen all the teeth brought away with the ligamentous gum, when it has been stript from the sockets of the lower jaw.\nTeeth are fixed as a general rule in all Vertebrata, and the only known exceptions are those presented by certain species of fishes, e.g. the Sharks, Lophioids, Gonio-donts. In the higher Vertebrata the movements of the teeth depend on those of the jaw-bones to which they are affixed, but appear to be independent in the ratio of the size of the tooth to the bone to which it is attached. Thus the extent of rotatory movement to which the large perforated poison fangs of the rattle-snake are subject depends upon the rotation of the small maxillary bone. So likewise the seemingly individual movements of divarication and approximation observable in the large lower incisors of the Bathyergus and Macropus *, are due entirely to the yielding nature of the symphysis uniting the two rami of the lower jaw in which those incisors are deeply and firmly implanted. It is no more a property of the teeth themselves than is that alternate removal of the lower teeth from, and bringing of them in contact with, the upper teeth of the mouth, which one sees or feels in the act of mastication.\nTrue teeth implanted in sockets are confined, in the Mammalian class, to the maxillary, premaxillary, and mandibular, or lower maxillary bones, and form a single row in each. They may project only from the premaxillary bones, as in the Narwhal, or only from the lower maxillary bone, as in Ziphius ; or be apparent only in the lower maxillary bone, as in the Cachalot ; or be limited to the superior and inferior maxillaries, and not present in the premaxillaries, as in the true Fecora, and most Bruta of Linnaeus ; in\n* See Mason Good\u2019s Book of Nature, vol. i. p. 285. 1826.\n899\ngeneral, teeth are situated in all the bones above mentioned. In Man, where the premaxillaries early coalesce with the maxillary bones, where the jaws are very short and the crowns of the teeth are of equal length, there is no interspace or \u201c diastema \u201d in the dental series of either jaw, and the teeth derive some additional fixity by their close apposition and mutual pressure. No inferior Mammal now presents this character ; but its importance, as associated with the peculiar attributes of the human organisation, has been somewhat diminished by the discovery of a like contiguous arrangement of the teeth in the jaws of a few extinct quadrupeds : e. g. Anoplotherium, Ncsodon, and Dichodon\u00df\nThe teeth of the Mammalia usually consist of hard unvascular dentine, defended at the crown by an investment of enamel, and everywhere surrounded by a coat of cement. The coronal cement is of extreme tenuity in Man, Quadrumana, and terrestrial Carnivora ; it is thicker in the Herbivora, especially in the complex grinders of the Elephant ; and is thickest in the teeth of the Sloths, Mega-therioids, Dugong, Walrus, and Cachalot. Vertical folds of enamel and cement penetrate the crown of the tooth in the Ruminants, and in most Rodents and Pachyderms, characterising by their various forms the genera of the last two orders ; but these folds never converge from equidistant points of the circumference of the crown towards its centre. The teeth of the quadrupeds of the order Bruta (Edentata, Cuv.) have no true enamel ; this is absent likewise in the molars of the Dugong and the Cachalot.)- The tusks of the Narwhal, Walrus, Dinoth\u00e9rium, Mastodon, and Elephant consist of modified dentine, which, in the last two great proboscidian animals, is properly called \u201civory,\u201d J and is covered by cement.\nIn the subjoined magnified view of a section of the molar of a Megatherium, t is the hard dentine, v the vaso-dentine, and c the cement {fig. 574).\nThe teeth in the Mammalia, as in the foregoing classes, are formed by superaddition of the hardening salts to pre-existing moulds of animal pulp or membrane, organised so as to insure the arrangement of the earthy particles according to that pattern which characterises each constituent texture of the tooth.\nThe complexity of the primordial basis, or matrix, corresponds, therefore, with that of the fully-formed tooth, and is least remarkable in those conical teeth which consist only\n* Quarterly Journal of the Geological Society, Feb. 1848, p. 36, pi. iv.\nf M. Fr. Cuvier divides the teeth of Mammalia, according to their composition, into four classes: the first consists of ivory (dentine), enamel, and cement ; the second of ivory and enamel ; the third of ivory and cement; the fourth of ivory only. (Dents des Mammif\u00e8res, p. xxi.) I have met with no Mammalian teeth in which cement is absent, and believe that the second and fourth of the above-cited classes of teeth have no existence in nature.\nJ \u201c Hoc solum est ebur.\u201d Plinius, Hist. Nat. lib. xi. c. 37.\n3 M 2","page":899},{"file":"p0900.txt","language":"en","ocr_en":"900\nTEETH.\nof dentine and cement. The primary pulp, of the same form and diameter throughout, which first appears as a papilla rising from the except in the immature animal, when it widens\nree surface of the alveolar gum, is the part of the matrix which by its calcification constitutes the dentine ; it sinks into a cell and becomes surrounded by a closed capsule in every mammiferous species, at an early stage of the formation of the tooth ; and, as the cement is the result of the ossification of the capsule, every tooth must be covered by a layer of that substance. In those teeth which possess enamel, the mould or pulp of that constituent is developed from the capsule covering the coronal part of the dentinal pulp. In the simple teeth the secondary or enamel pulp covers the crown like a cap ; in the complex teeth it sends processes into depressions of the crown, which vary in depth, breadth, direction, and number in the numerous groups of the herbivorous and omnivorous quadrupeds. The dentinal pulp, thus penetrated, offers corresponding complications of form ; and as the capsule follows the enamel pulp in all its folds and processes, the external cavities or interspaces of the dentine become occupied by enamel and cement ; the cement, like the capsule which formed it, being the outermost substance, and the enamel being interposed between it and the dentine. The dental matrix presents the most extensive interdigitation of the dentinal and enamel pulps in the Capybara and Elephant. The processes of formation and calcification of the several constituents of Mammalian teeth will be found described in the Introduction to my \u201c Odontography \u201d * and in the article Tooth.\nThe matrix of the Mammalian tooth sinks into a furrow and soon becomes inclosed in a cell in the substance of the jaw-bone, from which the crown of the growing tooth extricates itself by exciting the absorbent process, whilst the ceil is deepened by the same process and by the growth of the jaw into an alveolus for the root of tne tooth. Where the formative parts of the tootn are reproduced indefinitely to repair by their progressive calcification the waste to which the working surface of the crown of the tooth has been subject, the alveolus is of unusual depth, and\n* P. xli.\nto its bottom or base. In teeth of limited growth, the dentinal pulp is reproduced in progressively decreasing quantity after the completion of the exterior wall of the crown, and forms by its calcification one or more roots or fangs, which taper more or less rapidly to their free extremity. The alveolus is closely moulded upon the implanted part of the tooth ; and it is worthy of special remark that the complicated form of socket which results from the development of two or more fangs is peculiar to animals of the class Mammalia.*\nIn the formation of a single fang the activity of the reproductive process becomes enfeebled at the circumference, and is progressively contracted within narrower limits in relation to a single centre, until it ceases at the completion of the apex of the fang ; which, though for a long time perforated for the admission of the vessels and nerves to the interior of the tooth, is, in many cases, finally closed by the ossification of the remaining part of the capsule.\nWhen a tooth is destined to be implanted by two or more fangs, the reproduction of the pulp is restricted to two or more parts of the base of the coronal portion of the pulp, around the centre of which parts the sphere of its reproductive activity is progressively contracted. The intervening parts of the base of the coronal pulp adhere to the capsule, which is simultaneously calcified with them, covering those parts of the base of the crown of the tooth with a layer of cement. The ossification of the surrounding jaw being governed by the changes in the soft, but highly organised, dental matrix, fills up the\n* On the strength of this generalisation, I have established the Mammalian nature of the huge extinct animal called Basilosaurus by Dr. Harlan, and have advocated the claims of the diminutive jLmphitherium and Phascolotherium of the oolitic slate of Stonesfield to be admitted into the same high class, against the objections raised by M. de Blainville. See \u201c Comptes Rendus de l\u2019Acad. des Sciences,\u201d Oct. 22, 1838. The bifid base of the teeth of certain sharks not being implanted in a socket, forms no true exception to the rule enunciated in the text. See Geological Transactions, 2d series, vol. vi. p. 66.","page":900},{"file":"p0901.txt","language":"en","ocr_en":"TEETH.\n901\nspaces unoccupied by the contracted and divided pulp, and affords, by its periosteum, a surface for the adhesion of the cement or ossified capsule covering the completed part of the tooth.\nThe matrix of certain teeth does not give rise during any period of their formation to the germ of a second tooth, destined to succeed the first ; this, therefore, when completed and worn down, is not replaced: all the true Cetacea are limited to this simple provision of teeth. In the Armadillos, Me-gatherioids, and Sloths, the want of germinative power, as it may be called, in the matrix is compensated by the persistence of the matrix, and by the uninterrupted growth of the teeth.\nIn most other Mammalia, the matrix of the first developed tooth gives origin to the germ of a second tooth, which sometimes displaces, sometimes takes its place by the side of, its predecessor and parent. All those teeth which are displaced by their progeny are called temporary, deciduous, or milk teeth ; the mode and direction in which they are displaced and succeeded, \u2014 viz., from above downwards in the upper, from below upwards in the lower, jaw ; in both jaws vertically\u2014are the same as in the Crocodile ; but the process is never repeated more than once in any mammiferous animal. A considerable proportion of the dental series is thus changed; the second, or permanent teeth, having a size and form as suitable to the jaws of the adult, as the displaced temporary teeth were adapted to those of the young, animal. The permanent teeth, which assume places not previously occupied by deciduous ones, are always the most posterior in their position, and generally the most complex in their form. The successors of the deciduous incisors and canines differ from them chiefly in size ; the successors of the deciduous molars may differ likewise in shape, in which case they have always less complex crowns than their predecessors.*\nThe \u201c bicuspids,\u201d in Human Anatomy, and the corresponding teeth, called \u201cpremolars,\u201d in the lower Mammals, illustrate this law.\nThe first true molar owes the germ of its matrix to a vegetation or bud, separated by the fissiparous process from the matrix of the last deciduous tooth ; but the backward elongation of the jaw affords space for its development by the side of its progenitor, during which process it may in like manner give origin to a second, and this to a third, molar, succeeding each other from before backwards or horizontally.\nIn this successive germ-production, we find repeated the multiparous property of the dental matrix of the crocodile ; but the\n* \u201c C\u2019est une r\u00e8gle g\u00e9n\u00e9rale, que les molaires de remplacement ont une couronne moins compliqu\u00e9e que celles auxquelles elles succ\u00e8dent; mais cette couronne compliqu\u00e9e se trouve report\u00e9e sur les molaires permanentes qui viennent plus en arri\u00e8re.\u201d This generalisation was established by Cuvier, in his Le\u00e7ons d\u2019Anat. Comp., ed. 1805. vol. iii. p. 135.\nconcomitant growth of the jaw allows the second, third, and sometimes fourth generation of true molars to co-exist, and come into place side by side. In the Unguiculate, and most of the Ungulate, species of the placental division of the Mammalian class, the fissiparous reproduction of horizontally succeeding teeth stops at the third generation ; in other words, they have not more than three true molars on each side of the upper and lower jaws. In the Marsupial series, the same process extends to a fourth generation of true or horizontally succeeding molars* ; and in most of the species, the four true molars are in use and place at the same time; but in certain Kangaroos, the anterior ones are shed before the posterior ones are developed. This successive decadence is still more characteristic of the grinding teeth of the Elephant, which are finally reduced to a single molar tooth on each side of both jaws.\nThus the class Mammalia, m regard to the times of formation and the succession of the teeth, may be divided into two groups : \u2014 the \u201c Monophyodonts,\u201d\\ or those that generate a single set of teeth ; and the \u201c JDi-phyodonts,\u201d J or those that generate two sets of teeth.\nThe Monophyodonts include the orders Monotremata, JBruta (Edentata, Cuv.), and Cetacea (Cetacea vera, Cuv.) : all the rest of the order are Diphyodonts. In these, the first set of teeth are called the milk or deciduous teeth : the second set, the adult or permanent teeth ; although the teeth of this set are for the most part, like those of the first set, of limited growth, contracting to a root or roots, and being shed in greater or less proportion during the life-time of the species ; which life-time, in wild Carnivora and Herbivora, is dependent on, and would seem, indeed, to be determined by, the duration of the adult teeth.\nThe particulars of the Monophyodont dentition will be found under the Articles Monotremata, Vol. III. p. 387. ; Cetacea, Vol. I. pp. 563. 571. 573. ; (see my Odontography, p. 345. pis. 87\u201491.); and Edentata, Vol. II. p. 53. ; (see also Odontography, p.317. pis. 76\u201486.) Examples of some of the striking modifications of dental structure presented by recent or extinct animals of the order Bruta, are given in figs. 548. and 574. of the present article. It will be observed that I have qualified the generalisation as regards the Monophyodont character of the Cetacea, by citing only that part of Cuvier\u2019s order which he termed \u201c true or carnivorous Cetacea.\u201d The animals of the order Sirenia\n* This characteristic extension of the reproductive power of the matrices of the true molars in the Marsupials, is an approximation to the peculiar activity and persistence of the same power in the vertically succeeding teeth of the cold-blooded Ovi-para, and is associated with many other instances of the same affinity in more important parts of the organization of the implacental Mammals.\nf fj-woi, once ; <pCa, I generate ; olovs, tooth.\nj its, twice ; <pCa> and oSwi-\n3 M 3","page":901},{"file":"p0902.txt","language":"en","ocr_en":"902\nTEETH.\n(herbivorous Cetacea of Cuvier) differ in has been called in question.* I have, how\u00bb many organic particulars from the Cetacea ever, discovered in specimens of the Malayan\nFig. 575.\nDentition of the Dugong (Halicore indicus).\nproper*, and in none, perhaps, more strikingly than in having both deciduous and permanent teeth; this succession takes place, at least, with regard to the upper incisors of the Dugong, fig. 575.\nThese teeth project from the gum in the male sex ; but neither upper nor lower incisors are visible in the female.f The superior incisors are but two in number, in both sexes ; in the male, they are moderately long, subtriedral, slightly and equally curved, of the same diameter from the base, and deeply excavated to near the apex, which is obliquely bevelled off to a sharp edge, like the scalpriform teeth of the Rodentia. The form and extent of the persistent pulp-cavity of this tooth are shown in the figure of its longitudinal section, in my \u201c Odontography,\u201d pi. 93. fig. 4. ; it becomes longer and more pointed than in the permanent incisor of the younger male (fig. 575, i). When fully developed, only the extremity of this tusk projects from the jaw, at least seven-eighths of its extent being lodged in the socket, the parietes of which are entire ; and the exterior of the great premaxillary bones presents an unbroken surface. In the female Dugong, the growth of the permanent incisive tusks of the upper jaw is arrested before they cut the gum, and they remain through life concealed in the premaxillaries ; the tusk is solid, is about an inch shorter and less bent than that of the male ; it is also irregularly cylindrical, longitudinally indented, and it gradually diminishes to an obtuse rugged point ; the base is suddenly expanded, bent obliquely outwards, and presents a shallow excavation. These were conjectured by Home to be the \u201c milk-tusks ; \u201d they are, however, characteristic of sex, not of age ; and the existence of deciduous tusks at any period in the Dugong\n* Proceedings of the Zoological Society of London, 1838, p. 40.\nf Proceedings of the Zool. Society, 1838, p. 41.\nDugong which I have dissected at the Zoological Society, the true deciduous incisors of the upper jaw (fig. 575, d i) coexisting with the permanent ones {*'). They are much smaller than the permanent tusks of the female, and are loosely inserted by one extremity in conical sockets immediately anterior to those of the permanent tusks, adhering by their opposite ends to the thick tegumentary gum, which presented no outward indication of their presence.\nWhen this gum was stripped off the bone, the deciduous tusks came away with it ; and this may account for their usual absence in dried crania of immature Dugongs, in which, nevertheless, their alveoli are generally sufficiently conspicuous. True permanent incisors are not developed in the lower jaw of the Dugong ; those which are occasionally found there are abortive remnants of the first or deciduous series, which are not destined at any time to rise above the gum (fig. 575, d i 3.).\nThe molar teeth of the Dugong resemble those of the order Bruta in the total absence of enamel, and of any constriction defining the crown from the fangs. In the Malayan species, only five molars (fig. 575, 1, 2, 3, 4, 5.) are developed on each side of both jaws : in the Australian Dugong six are developed ; i. e. the Halicore indicus is characterised by\nthe molar formula m. f-\u2014~=20, whilst the o\u20145\nHalicore australis has m. ^\u2014-=24.j' But in 6\u2014o\nboth species, the number is progressively reduced, by the shedding of the anterior and\nsmaller molars, to m. ?\u2014?=8. The struc-\n&---\u00c4\nture of these molar teeth is illustrated in\n* Dr. Knox, Edinburgh Philosophical Transactions, tom. xi. p. 389.\nj- See my appendix to Juke\u2019s \u201c Voyage of the Fly.\u2019","page":902},{"file":"p0903.txt","language":"en","ocr_en":"TEETH.\n903\n\u00dfg. 546. B, their form inj\u00c7g. 546. a; the last molar, when it comes into use, presents a bilobed form of grinding surface, as is shown at b,fig. 575.\nOwing to there being but one set of molars in the Dugong, those teeth cannot be divided into true and false molars, any more than in the Sloths or Armadillos. In the true Di-phyodonts, in which each kind of teeth have deciduous predecessors, those grinders which succeed the deciduous ones vertically, and displace them, are called \u201c premolars,\u201d or \u201c false molars,\u201d and those that come into place behind these, without pushing out vertically any predecessors, are the \u201c molars proper,\u201d or \u201c true molars.\u201d In this article, as in my \u201c Odontography,\u201d the two sorts of grinders are called respectively \u201c premolars \u201d and \u201cmolars.\u201d In the Marsupial order the normal number of molars is four in each 4______________________4\ndental series, i. e. to. -\u2014in the placental 4\u20144\nDiphyodonts their normal number is three, 3_________3\ni. e. m. - : the normal number of pre-\n3\u20143\t1\n3___3\nmolars in the Marsupialia is -\u2014-, but in the\nO\u2014O\nPlacentalia, it is : in both the numerical 4\u20144\ncharacter of the canines is one, i. e. -\u2014- ; that\nof the incisors three, i. e.\n3\u20143\n3\u20143\u2019\nAs regards\nthe latter teeth, however, the number of exceptions in the Marsupialia is considerable, and the incisors are sometimes in excess ; whilst in the placental Diphyodonts, the incisors never exceed the typical number, but frequently depart from it by suppression or arrest of development.\nIn fishes and reptiles, certain teeth might be called \u201c incisive,\u201d \u201c laniary,\u201d or \u201c molar\u201d teeth, in reference to the special adaptation of their form for cutting, tearing, or bruising; but such terms, in the cold-blooded classes, imply nothing more than those modifications of form ; they are not significative of constant and well-defined groups of teeth, and could not become the names of definite parts or organs determinable and traceable from one species to another. In the Mammalian orders, with two sets of teeth, these organs acquire fixed individual characters, receive special denominations, and can be determined from species to species. This individualisation of the teeth is eminently significative of the high grade of organisation of the animals manifesting it ; especially when we consider the great proportion of mineral substance which enters into the composition of those parts ; in the number and nature of which the principle of vegetative repetition, and the power of the general polarising forces, have been most controlled in the Mammalia.\nOriginally, indeed, the name \u201c incisors,\u201d \u201claniaries\u201d or \u201ccanines,\u201d and \u201cmolars\u201d were given to the teeth, in Man and certain mammals, as in reptiles, in reference merely to\nthe shape and offices so indicated ; but they are now used as arbitrary signs, in a more fixed and determinate sense. In some Carnivora, e.g., the front teeth have broad tuberculate summits, adapted for nipping and bruising, while the principal back teeth are shaped for cutting, and work upon each other like the blades of scissors. The front teeth in the elephant project from the upper jaw, in the form, size, and direction of long pointed horns. In short, shape and size are the least constant of dental characters in the Mammalia; and the homologous teeth are determined, like other parts, by their relative position, by their connections, and by their development.\nThose teeth which are implanted in the premaxillary bones, and in the corresponding part of the lower jaw, are called \u201c incisors,\u201d whatever be their shape or size. The tooth in the maxillary bone, which is situated at, or near to, the suture with the premaxillary, is the \u201c canine,\u201d as is also that tooth in the lower jaw which, in opposing it, passes in front of its crown when the mouth is closed. The other teeth of the first set are the \u201c deciduous molars ; \u201d the teeth which displace and succeed them vertically are the \u201c premolars ;\u201d the more posterior teeth, which are not displaced by vertical successors, are the \u201cmolars \u201d properly so called.\nWhen the premolars and the molars are below their typical number, the absent teeth are missing from the fore-part of the premolar series and from the back part of the molar series. The most constant teeth are the fourth premolar and the first true molar ; and, these being known by their order and mode of development, the homologies of the remaining molars and premolars are determined by counting the molars from before backwards, e. g. \u201c one,\u201d \u201c two,\u201d \u201c three ; \u201d and the premolars from behind forwards, e. g. \u201c four,\u201d \u201c three,\u201d \u201c two,\u201d \u201c one.\u201d The incisors are counted from the median line, commonly the foremost part of both upper and lower jaws, outwards and backwards. The first incisor of the right side is the homotype, transversely, of the contiguous incisor of the left side in the same jaw, and, vertically, of its opposing tooth in the opposite jaw ; and so with regard to the canines, premolars, and molars ; just as the right arm is the homotype of the left arm in its own segment, and also of the right leg of a succeeding segment. It suffices, therefore, to reckon and name the teeth of one side of either jaw in a species with the typical number and kinds of teeth ; e.g. the first, second, and third incisors,\u2014 the first, second, third, and fourth premolars, \u2014 the first, second, and third molars ; and of one side of both jaws in any case.\nThe homologous teeth being thus determinable, they may be severally signified by a symbol as well as by a name. The incisors, e.g., by their initial letter i., and individually by an added number, i. 1, i. 2, and i. 3 ; the canines by the letter c. ; the premolars by the letter p.; and the molars by 3 m 4","page":903},{"file":"p0904.txt","language":"en","ocr_en":"TEETH.\n904\nthe letter m. ; these also being differentiated by added numerals. Thus, the number of these teeth, on each side of both jaws, in any given species, Man e.g., may be expressed\ng___2\nby the following brief formula : \u2014 i. ^\n\\__I g______2\t3___3\nc- p- m- 3^3=32; and the homologies of the individual teeth, in relation to the typical formula, may be signified by i. 1., i. 2. ; c. ; p. 3., p. 4. ; m. 1., in. 2., m. 3. : the suppressed teeth being i. 3.*, p. 1., and y\u00bb. 2.\nExamples of the typical dentition are exceptions in the actual creation ; but it was the rule in the forms of Mammalia first introduced into this planet ; and that, too, whether the teeth were modified for animal or vegetable food. Fig. 576., e. g., shows the dental series\nThe true molars in the one are tuberculate, indicating its tendency to vegetable diet; in the other, they are carnassial, and betoken a peculiarly destructive and bloodthirsty species.\nIn the Quarterly Geological Journal, No. 13, 1848, p. 36. *pl. iv., I have described and figured the entire dental series of one side of the lower jaw of an extinct hoofed quadruped, the Dichodon cuspidatus, from eocene or oldest tertiary strata, also manifesting the normal number and kinds of teeth, but with such equality of height of crown, that no interspace is needed to lodge any of the teeth when the jaws are closed, and the series is as entire and uninterrupted as in the human subject. A great proportion of the upper jaw and teeth has been discovered, and\nFig. 576.\nDentition of the Amphicyon major. Upper jaw.\nof the upper jaw of the Amphicyon major, a the marks of abrasion on the lower teeth mixed-feeding ferine animal, allied to the prove the series above to have been as entire Bear. Fig. 577. shows the dental series of and continuous as that below. The Anoplo-the under jaw of a more strictly carnivorous therium (\u201cOdontography,\u201d pi. 135. fig. 1.),\nFig. 577.\nDentition of the Hy\u0153nodon. Lower jaw.\nbeast, the Hy\u0153nodon ; the fossil remains of a species of which have been discovered in the oldest tertiary deposits of Hampshire. The symbols denote the homologies of the teeth.\n* I have been guided by the analogy of the hare (Odontography, p. 410, pi. 104, fig. 5.) in this determination ; but a contradictor might indulge his instinct without liability to disproof from actual knowledge.\nfrom the gypsum quarries of Montmartre, geologically as ancient as the eocene clays of this island, long ago presented to Cuvier the same peculiar continuous dental series as is shown in the Dichodon. In his original Memoir, Cuvier described the canines as a fourth pair of incisors, on account of their small size and their trenchant shape ; but he afterwards recognised their true homology with","page":904},{"file":"p0905.txt","language":"en","ocr_en":"TEETH.\n905\nthe larger and more laniariform canines of the Pal\u0153otherium (\u201c Odontography,\u201d pi. 135., dg. 4.). The Ch\u00e6ropotamus *, the Anthraco-therium\\, the Hyopotamus\\, the Hyracothe-rium\u00a7, the Oplotherium, the Merycopotamus, the Hippohyus, and other ancient (eocene and miocene) tertiary mammalian genera presented the forty-four teeth, in number and kind according to that which is here propounded as the typical or normal dentition of the placental Mammalia. Amongst the existing genera, the hog (Sus) is one of the few that retain this type. Fig. 578. shows the entire permanent series, exposed, in both\nmolar, m. 2, has just begun to cut the gum ; p. 2, p. 3, and p. 4-, together with in. 3, are more or less incomplete and concealed in their closed alveoli.\nThe premolars must displace deciduous molars in order to rise into place ; the molars have no such relations ; it will be observed, that the last deciduous molar, d. 4, has the same relative superiority of size to d. 3 and d. 2 which m. 3 bears to m. 2 and m. 1 ; and the crowns of p. 3 and p. 4 are of a more simple form than those of the milk-teeth which they are destined to succeed.\nTeeth of each of the kinds above deter-\nFig. 578.\nDentition of the Hog (Sus).\njaws, and indicated individually by their mined, and arbitrarily named \u201c incisors,\u201d \u201c ca-symbols. Fig. 579. illustrates the phenomena nines,\u201d \u201c premolars,\u201d \u201c molars,\u201d have received of development which distinguish the pre- other special names in regard to certain pe-\nFig. 579.\nDeciduous and permanent teeth (Sus). Lower jaw.\nmolars from the molars. The first premolar, p. 1, and the first molar, m. 1, are in place and use, together with the three deciduous molars, d. 2, d. 3, and d. 4 ; the second\n* History of British Fossil Mammalia, p. 416, fig. 164.\nf Jobert, Annales des Sciences, t. xvii. p. 139.\nX Quarterly Journal of the Geological Society, May, 1848, p. 103, pi. viii.\n\u00a7\" Geological Transactions, 2nd series, vol. vi. p. 203.\nculiarities of form or other property ; and the ablest comparative anatomists have been led astray in determining their homologies when they have suffered themselves to be guided exclusively by morphological characters. The premolars in the human subject have been called \u201c bicuspids.\u201d The last upper premolar and the first lower true molar in the Carnivora are termed, from their peculiar form, \u201c sectorials,\u201d or \u201c carnassial teeth,\u201d \u201cmolaires carnassi\u00e8res\u201d of Cuvier, Teeth","page":905},{"file":"p0906.txt","language":"en","ocr_en":"906\nTEETH.\nof an elongated conical form, projecting considerably beyond the rest, and of uninterrupted growth, are called \u201ctusks ; \u201d such are the incisors of the Elephant and Dugong, the canines of the Boar and Walrus : the long and large incisors of the Rodents have been termed, from the shape and structure of their cutting edge, scalpriforrn or chisel-teeth, \u201c dentes scalprarii.\u201d The inferior incisors of the flying Lemurs (Galeo-pithecus) have the crown deeply notched like a comb, and are termed. \u201c dentes pectinati.\u201d The canines of the Baboons are deeply grooved in front, like the poison-fangs, \u201c dentes canaliculati,\u201d of some serpents. The compressed conical crowns of the molar teeth of the small clawed seals (Stenorhynchus) are divided either like a trident, into three sharp points, or like a saw, into four or five points ; the molars of the great extinct Zeuglodon had a similar form ; such teeth have been called dentes serrati. But the philosophical course of the knowledge of nature tends to explode needless terms of art, invented for unimportant varieties, and to establish and fix the meaning of those terms that are the signs of determinate species of things.\nThe Cuviers divided the molar series of teeth, according to their form, into three kinds: \u201cfalse molars,\u201d \u201c carnassials,\u201d and \u201c tubercular molars ; \u201d and, in giving the generic characters of Mammalia, based the dental formulae on this system : thus the genus Felis is characterised\n2__2\nas having \u201cfausses molaires -\u2014\ncarnassi\u00e8res\n1\u20141,\n1\u20141\ntuberculeuses\n1\u20141 8\u201e*\n0\u20140 ; \u2014 6\nThe uninterrupted line marked \u201cCuvier\u201d in V. Felis of fig. 580., intersects the teeth in each jaw called carnassi\u00e8res; those anterior to them being the teeth called \u201c fausses molaires the single tooth behind in the upper jaw is the \u201c tuberculeuse.\u201d Most Zoologists, both at home and abroad, have adopted the Cuvierian system of formalising the molar teeth. It seems a very natural one in the case of the Cat\n* \u201c Les Dents des Mammif\u00e8res consid\u00e9r\u00e9es comme Caract\u00e8res zoologiques,\u201d 8vo. p. 77. In the original the numbers\nare given f. m. c. ^ ; t. -, the teeth\nof each side being clubbed together; they are distinguished into right and left in the text, to facilitate the comparison with the formulae used in this Article.\nFig. 580.\nHomo.\nII Ursus.\nCanis.\nCuvier. De Bl.\nHomologies of the teeth in Diphyodont Mammals.","page":906},{"file":"p0907.txt","language":"en","ocr_en":"TEETH.\n607\ngenus ; the tooth p. 4 above plays upon that, m. 1, below, which has a similar remarkable carnassial modification of form ; they fit, indeed, almost as Cuvier describes, like the blades of a pair of scissors; the two teeth in advance of the carnassial in the upper jaw (p. 3, p. 2) in like manner are opposed to the same number of \u201c fausses molaires \u201d (p. 4, p. 3) in the under jaw, and the canine c. above plays upon the canine below ; all seems straightforward and symmetrical, save that the little tubercular, m. 1, above has no opponent in the lower jaw. And, perhaps, the close observer might notice that, whilst the upper canine, c., glides behind its homotype below, the first upper false molar (p. 2) passes anterior to the crown of the first false molar (p. 3) below; and that the second false molar and carnassial of the upper jaw are also a little in advance of those teeth in the under jaw when the mouth is shut.\nIn passing to the dentition of the Dog (fig. 580, III. Canis), formulised by Cuvier as:\n3\u20143\t,v\t1\u2014I\n\u201c fausses molaires ^ y, carnassi\u00e8res\ttu-\nberculeuses ^^ ; ==\tit will be ob-\nserved that here the first upper false molar (p. 1) differs from that in Felis, inasmuch as, when the mouth is shut, it preserves the same relative position to its opponent below (p. 1) which the upper canine does to the lower canine, and that the same may be said of the second and the third false molars ; but that with regard to the carnassial above (p. 4) this tooth repeats the same relative position in, regard to the fourth false molar below (p. 4), and not to that tooth, m. 1, which Cuvier regarded as the lower homotype of the carnassial ; and, indeed, the more backward position of the lower carnassial is so slight that its significance might well be overlooked, more especially as the two succeeding tubercular teeth above were opposed to two similar tuberculars below. Cuvier therefore leaves us to conclude that the tooth which had no homotype or answerable opponent above was either the fourth \u201c fausse molaire \u201d below, or else the first. How unimportant size and shape are, and how significant relative position is in the determination of the homologies of teeth as of other parts, may be learnt before quitting the natural order of Carnivora ; e. g. by the condition of the dental system in the Bear (fig. 580, II. Ursus). Here the lower tooth, m. 1, instead of presenting the carnassial character, and resembling in form the upper tooth (p. 4), which is the homologue of the upper carnassial in the dog, has a tubercular crown, and corresponds in size as well as shape with the upper tooth m. 1, to which it is almost wholly opposed, and with the same slight advance of position which we observe in the lower canine as compared with the upper one, and in the four lower premolars (p. 1, p. 2, p. 3, p. 4) as compared with their veritable homotypes above. F. Cuvier divides the molar series of the\ngenus Ursus into \u201c fausses molaires j\u2014\n1 \u2014 1\tt . 2\u20142 12 \u201e\ncarnassi\u00e8res j-, tuberculeuses\t\u2014 yy*\nThe tendency in every thinker to generalise and to recognise Nature\u2019s harmonies, has led him here to use the term \u201c carnassi\u00e8re \u201d in an arbitrary sense, and to apply it to a tooth above (p. 4), which he owns has such a shape and diminished size as would have led him to regard it as merely a false molar, but that the upper carnassial would then have entirely disappeared ; and it has also led him to give the name \u201c carnassi\u00e8re \u201d to a tooth below, m. 1, which he, nevertheless, describes as having a tubercular and not a trenchant crown. In so natural a group as the true Carnivora it was impossible to overlook the homologues of the trenchant carnassials of the lion, even when they had become tubercular in the omnivorous bear ; and Cuvier therefore, having determined and defined the teeth so called in the feline genus, felt compelled to distinguish them by the same names after they had lost their specific formal character. And if, indeed, he had succeeded in discovering the teeth which were truly answerable or horaotypal in the upper and lower jaws, the term \u201c carnassial \u201d might have been retained as an arbitrary one for such teeth, and have been applied to their homologues in Man, the Ruminant, or the Pachyderm, where they are as certainly determinable \"as in those aberrant Carnivores, in which they have equally lost their sectorial shape. But the inconvenience of names indicative of such specialties of form will be very obvious when the term \u201c tuberculeuses\u201d comes to be applied to the three hindmost teeth in the Hy\u0153nodon (fig. 577.), which teeth answer to the broad crushing teeth, m. 1, m. 2, and m. 3, in the bear and some other existing Carnivora. The analogous term \u201c molar,\u201d having a less direct or descriptive meaning, is therefore so much the better as the requisite arbitrary name of a determinate species of t\u00ebeth.\nHad Cuvier been guided in his determinations of the teeth by their mutual opposition in the closed mouth, and had studied them with this view in the Carnivora, with the dentition most nearly approaching to the typical formula, viz. the bear, he could then have seen that the three small and inconstant lower premolars (p. 1, p. 2, p. 3) were the homotypes of the three small and similarly inconstant premolars above; that the fourth false molar (p. 4) below, which, as he observes, \u201c alone has the normal form,\u201d * was truly the homotype of the tooth above (p. 4), which he found himself compelled to reject from the class of \u201c fausses molaires,\u201d notwithstanding it presented their normal form; that the tubercular tooth, m. I, which he calls \u201c carnassi\u00e8re \u201d in the lower jaw, was the veritable homotype of his first \u201c molaire tuberculeuse \u201d above (m. 1), and that the tooth in the inferior series which had no answerable one above was his second \u201c tuber-\n* Dents des Mammif\u00e8res, p. 111.","page":907},{"file":"p0908.txt","language":"en","ocr_en":"908\nTEETH.\nculeuse \u201d (my m. 3), and not any of the four false molars. The true second tubercular above ([m. 2) is, however, so much developed in the bear as to oppose both m. 2 and vi. 3 in the lower jaw, and it might seem to include the homotypes of both those teeth coalesced. One sees with an interest such as only these homological researches could excite, that they were distinctly developed in the ancient Amphicyon (fig. 576.), which accordingly presents the typical formula. Thus, I repeat, the study of the relative position of the teeth of the bear might have led to the recognition of their real nature and homologies, and have helped to raise the mask of their extreme formal modifications, by which they are adapted to the habits of the more bloodthirsty Carnivora. But the truth is plainly and satisfactorily revealed when we come to trace the course of development and succession of these teeth. The weight which must ever attach itself to an opinion sanctioned by the authority of both the Cuviers, demands that a conclusion contrary to theirs, and which seems to be opposed by Nature herself in certain instances, should be supported by all the evidence of which such conclusion is susceptible.\nI proceed, therefore, to show how, in the bear, my determinations of the teeth are established by their development, as well as by their relative position. As the question only concerns the molar series, the remarks will be confined to these. In the jaws of the young bear, figured in cut 581., the first premolar, p. 1, is the only one of the permanent series in place ;\nsimilarity to p. 4 in the lower jaw (fig. 581, Ursus), to be veritably the last of the premolar series, and to agree not in shape only, but in every essential character, with the three preceding teeth called by Cuvier \u201cfausses molaires.\u201d So, likewise, in the lower jaw, we see that the primitive deciduous series, d. 1 ,d. 2, d. 3, and d. 4, will be displaced by the corresponding premolars, p. 1 ,p. 2, p. 3, and p. 4 ; and that the tooth m. 1, called carnassi\u00e8re by Cuvier, in the lower jaw, differs essentially from that p. 4, so called in the upper jaw by being developed without any vertical predecessor or deciduous tooth.\nThe same law of development and succession prevails in the genus Cards (fig. 582.). Although the tooth m. 1 in the lower jaw has exchanged the tubercular for the carnassial form, it is still developed, as in the bear, behind the deciduous series, and independently of any vertical predecessor ; and the tooth p. 4 above, although acquiring a relative superiority of size to its homologue in the bear, and more decidedly a carnassial form, is not the homotype of the permanent carnassial below, but of that premolar (p. 4) which is destined to displace the deciduous carnassial d. 4. The symbols sufficiently indicate the relations of the other teeth, and the conclusions that are to be drawn from them as to their homologies. It is interesting to observe in the deciduous, as well as in the permanent series, that the lower carnassial d. 4 is not the homotype of the upper one d. 3, but of the tooth which Cuvier calls the \u201c tuberculeuse du lait,\u201d d. 4 in the upper jaw.\nFig. 581.\nDeciduous and permanent dentition of the Bear (Ursus).\nthe other grinders in use are the deciduous molars, d. 2, d. 3, and d. 4; d. 2 will be displaced by p. 2, d. 3 by p. 3, and d. 4 by the tooth p. 4, which, notwithstanding its size and shape, Cuvier felt himself compelled to discard from the series of false molars, but which we now see is proved by its developmental relations to d. 4, as well as by its relative position and\nIn the genus Felis (fig. 580.), the small permanent tubercular molar of the upper jaw, m. 1, has cut the gum before its analogue d. 4 of the deciduous series has been shed ; but though analogous in function, this is not homologous with, or the precedent tooth to m. 1, but, as in the dog, to the great carnassially modified premolar, p. 4. In the lower jaw the","page":908},{"file":"p0909.txt","language":"en","ocr_en":"TEETH.\n909\ntooth (\u00bb*. 1), which is functionally analogous to tition, are m. 2 in the upper jaw, m. 2 and m. 3 the carnassial above, is also, as in the dog, the in the lower jaw ; p. 1 in the upper jaw, 1\nFig. 582.\nDeciduous and permanent teeth in the Dog (Canis).\nfirst of the true molar series, and the homo- and p. 2 in the lower jaw ; thus illustrating the type of the little tubercular tooth (m. 1) above, rule enuntiated above, that, when the molar And the homologies of the permanent teeth series falls short of the typical number it is p. 4> above and in. 1 below, with those so from the two extremes of such series that the\nFig. 583.\nDeciduous and permanent teeth in the Lion (Felis).\nsymbolised in the dog (fig. 582.), teach us teeth are taken, and that so much of the that the teeth which are wanting, in order to series as is retained is thus preserved unbroken, equal the number of those in the canine den- In the great extinct sabre-toothed tiger (Ma-","page":909},{"file":"p0910.txt","language":"en","ocr_en":"TEETH.\n910\nchairodus, fig. 580, VI.*), the series is still further reduced by the loss ofp. 2 in the upper jaw.\nThat the student may test for himself the demonstration which the developmental characters above defined, yield of the true nature and homologies of the feline dentition,\u2014 the most modified of all in the terrestrial Carnivora, he is recommended to compare with nature the following details of the appearance and formation of the teeth in the common cat. In this species the deciduous incisors d.i. begin to appear between two and three weeks old ; the canines d. c. next, and then the molars d. m. follow, the whole being in place before the sixth week. After the seventh month they begin to fall in the same order; but the lower sectorial molar m. 1, and its tubercular homotype above (m. 1) appear before d. 2, d. 3, and d. 4 fall. The longitudinal grooves are very faintly marked in the deciduous canines. The first deciduous molar (d. 2), in the upper jaw is a very small and simple one-fanged tooth ; it is succeeded by the corresponding tooth of the permanent series, which answers to the second premolar ( p. 2) of the hyaena and dog. The second deciduous molar (d. 3) is the sectorial tooth ; its blade is trilobate, but both the anterior and posterior smaller lobes are notched, and the internal tubercle, which is relatively larger than in the permanent sectorial, is continued from the base of the middle lobe, as in the deciduous sectorial of the dog and hy\u00e6na ; it thus typifies the form of the upper sectorial, which is retained in the permanent dentition of several Viverrine and Musteline species. The third or internal fang of the deciduous sectorial is continued from the inner tubercle, and is opposite the interspace of the two outer fangs. The Musteline type is further adhered to by the young Feline in the large proportional size of its deciduous tubercular tooth, d. 4. In the lower jaw, the first milk-molar (d. 3) is succeeded by a tooth (/>. 3) which answers to the third lower premolar in the dog and civet. The deciduous sectorial (d. 4), which is succeeded by the premolar (p. 4), answering to the fourth in the dog, has a smaller proportional anterior lobe, and a larger posterior talon, which is usually notched ; thereby approaching the form of the permanent lower sectorial tooth in the Mustelulce.\nIn the article Carnivora (vol. i. p. 478.), the remarks on the teeth are limited chiefly to their physiological adaptations. A description of some of their more remarkable structures will here be given, according to the idea of the nature of the teeth above developed. The dental formula of the dog, jackal, wolf, and fox, is illustrated in fig. 580, III. Canis.\n* Machairodus, from\ta sabre ; and o&ol;,\na tooth. This generic name was imposed by Dr. Kaup on the extinct animal which was armed with canine teeth, like that figured in fig. 580, YI. Such teeth, long, compressed, falciform, sharp-pointed, and with anterior and posterior finely-serrated edges, were first discovered in tertiary strata in Italy and Germany, and were referred by Cuvier to a species of bear, under the name of Ur sus cultridens. Fossil canines of this genus have been found in Kent\u2019s Hole cave, Torquay.\nIn the Megalotis, or Long-eared Fox (Oto-cyon, Licht.), the deviation from the typical dentition of the Canid\u0153 is effected by excess of development ; two additional true molars being present on each side of the upper, and one on each side of the lower jaw, in the permanent series of teeth ; and an approach is made by the modified form of the sectorial molar and of some of the other teeth to the dentition of the Viverrid\u0153. This family of Carnivora, which comprehends the Civets, Genets, Ichneumons, Musangs, Sarikates, and Mangues, is characterised, with few exceptions,\n3___3 I______i\nby the following formula : \u2014 i. ^^ ; c. -,\u2014 ;\n4___4 g_______2\np. ^ y ; m. g____Q : = 40. It differs from that\nof the genus Canis by the absence of a tubercular tooth (m. 3) on each side of the lower jaw ; but, in thus making a nearer step to the typical carnivorous dentition, the Viverrid\u0153, on the other hand, recede from it by the less trenchant and more tubercular character of the sectorial teeth, as is shown in the figures of the teeth of the Viverra indica, in my \u201c Odontography,\u201d pi. 126. figs. 1, 2, and 3.\nThe canines are more feeble, and their crowns are almost smooth ; the premolars, however, assume a formidable size and shape in some aquatic species, as those of the subgenus Cynogale, in which their crowns are large, compressed, triangular, sharp-pointed, with trenchant and serrated edges, like the teeth of certain sharks, (whence the name Squalodon, proposed for one of the species), and well adapted to the exigencies of quadrupeds subsisting principally on fish : the opposite or obtuse, thick form of the premolars is manifested by some of the Musangs, as Paradoxurus auratus. The upper sectorial tooth, p. 4, is characterised by having its inner tubercle larger, the middle conical division of the blade thicker, and the posterior one smaller than in the genus Canis. This tooth advances to beneath the ant-orbital foramen in the Musangs (Paradoxurus) : it is situated farther back in the Civets and Genets, in which the blade of the sectorial is sharper. This shmvs that relative position to the zygomatic or molar process of the maxillary is not a good character.\nIn the lower jaw the sectorial tooth (m. 1) manifests its true molar character by the presence of an additional pointed lobe on the inner side of the two lobes forming the blade at the fore-part of the crown : the posterior, low, and large lobe of the tooth being also tri-tuberculate, as in the dog. The last molar (m. 2) has an oval crown with four small tubercles, resembling the penultimate lower molar in the dog, with which it corresponds.\nThe deciduous dentition consists, in the\n3___3\nViverrine family, of : incisors -\u2014\u2014 ; canines\nO---\u00f4\n]__j\t3__3\ny\u2014; molars y\u2014y : = 28. If the first permanent premolar has any predecessor, it must be rudimental and disappear early in","page":910},{"file":"p0911.txt","language":"en","ocr_en":"TEETH\n911\nboth jaws ; the second premolar displaces the first normally developed deciduous molar; the third upper premolar displaces and succeeds the deciduous sectorial, which has a sharper and more compressed blade, and a relatively smaller internal tubercle, than the permanent sectorial. This tooth displaces the last deciduous molar, which is a tubercular tooth, resembling in form the first of the two upper permanent tuberculars ; these coming into place without pushing out any predecessors, enter into the category of true molar teeth. In the lower jaw the third premolar displaces the deciduous sectorial, which has three trenchant lobes and a relatively smaller posterior talon than the permanent sectorial. The fourth premolar displaces the third or tubercular milk-molar. The permanent sectorial and tubercular molars displace no predecessors, and are therefore m. 1 and m. 2.\nThe first premolar, p. 1, is not developed at any period in the Mangues (Crossarchus), the Suricates (Ryz\u0153na), or the Mangusta \u2022paludinosa ; these Viverrines, therefore, retain throughout life more of the immature characters of the family, and in the same degree approach in the numerical characters of their dentition to the more typical Carnivora.\nThe alternate interlocking of the crowns of the teeth of the upper and lower jaws, which is their general relative position in the Carnivora, is well marked in regard to the premolars of the Viverridce (fig. 580, IV.) : as the lower canine is in front of the upper, so the first lower premolar rises into the space between the upper canine and first upper premolar ; the fourth lower premolar in like manner fills the space between the third upper premolar (p. 3) and the sectorial tooth (p. 4), playing upon the anterior lobe of the blade of that tooth which indicates by its position, as by its mode of succession, that it is the fourth premolar of the upper jaw. The first true molar below, modified as usual in the Carnivora to form the lower sectorial, sends the three tubercles of its anterior part to fill the space between the sectorial (p. 4) and the first true molar (m. 1) above. In the Mu-sangs the lower sectorial is in more direct opposition to its true homotype, the first tubercular molar in the upper jaw ; and these Indian Viverridce (Paradoxuri) are the least carnivorous of their family, their chief food consisting of the fruit of palm -trees, whence they have been called \u201c Palm-cats.\u201d\nHy\u00e6na.\u2014 The dentition of this genus presents a nearer approach to the strictly carnivorous type by the reduction of the tubercular molars to a single minute tooth on each side of the upper jaw, the inferior molars being all conical or sectorial teeth : the molar teeth in both jaws are larger and stronger, and the canines smaller in proportion than in the Feline species, from the formula of which the dentition of the hy\u00e6na differs numerically only in the retention of an additional premolar tooth, p. 1 above and p. 2 below, on each side of both jaws. The dental\n3__3\nformula of the genus Hy\u00e6na is: \u2014 in. \u2014\u2014-, 1\u20141\t4\u20144\t1\u20141\t3\u20143\nc\u2018 JUT5 Pm' 3H3\u2019 m\u2018 1ZI7: =: 34. The\ncrojvns of the incisors form almost a straight tranverse line in both jaws, the exterior ones, above, being much larger than the four middle ones, and extending their long and thick inserted base further back : the crown of the upper and outer incisor (i. 3.) is strong, conical, recurved, like that of a small canine, with an anterior and posterior edge, and a slight ridge along the inner side of the base. The four intermediate small incisors have their crown divided by a transverse cleft into a strong anterior, conical lobe, and a posterior ridge, which is notched vertically; giving the crown the figure of a trefoil. The lower incisors gradually increase in size from the first to the third ; this and the second have the crown indented externally ; but they have not the posterior notched ridge like the small upper incisors ; the apex of their conical crown fits into the interspace of the three lobes of the incisor above. The canines have a smooth convex exterior surface, divided by an anterior and posterior edge from a less convex inner side : this surface is almost flat and of less relative extent in the inferior canines. The first premolar above (p. 1) is very small, with a low, thick, conical crown : the second presents a sudden increase of size, and an addition of a posterior and internal basal ridge to the strong cone. The third premolar exhibits the same form on a still larger scale, and is remarkable for its great strength. The posterior part of the cone of each of these premolars is traversed by a longitudinal ridge. The fourth premolar is the carnassial tooth, and has its long blade divided by two notches into three lobes, the first a small thick cone, the second a long and compressed cone, the third a horizontal sinuous trenchant plate : a strong triedral tubercle is developed from the inner side of the base of the anterior part of the crown. The single true molar of the upper jaw (m. l) is a tubercular tooth of small size : transversely oblong in the Hy\u00e6na vulgaris and H.fusca; smaller and sub-circular in the Hy\u00e6na crocuta ; still smaller and implanted by a single fang in the Hy\u00e6na spel\u00e6a : in all the existing species of Hy\u00e6na it has two fangs. The first premolar of the lower jaw (p. 2) fits into the interspace between the first and second premolars above, and answers, therefore, to the second lower premolar in the Viverrid\u00e6 : it is accordingly much larger than the first (p. 1) above ; it has a ridge in the fore-part of its cone, and a broad basal talon behind. The second (p. 3) is the largest of the lower premolars, has an anterior and a posterior basal ridge, with a vertical ridge ascending upon the fore as well as the back part of the strong rounded cone : the third premolar (p. 4.) is proportionably less in the Hy\u00e6na crocuta than in the H. vulgaris: its posterior ridge is developed into a sma-i cone; the last tooth (m. 1) is the sectorial,","page":911},{"file":"p0912.txt","language":"en","ocr_en":"912\tTEETH.\nand consists almost entirely of a blade divided by a vertical fissure into two sub-equal compressed pointed lobes : the points are less produced than in the Felines, but the lower sectorial of the hyaena is better distinguished by the small posterior basal talon, from which a ridge is continued along the inner side of the base, and is slightly thickened at the fore-part of the crown. According to the relative position of the crowns of the premolars the third below ought to be the last, being analogous to the fourth in the Viverrid\u0153, and the sectorial should be first true molar : we shall find this view confirmed by the test of the mode of succession of the permanent teeth. But the mode of implantation of the premolar and molar teeth may first be noticed. The first upper premolar has but one fang; the second and third have each two ; the sectorial tooth has three, the two anterior ones on the same tranverse line, the inner one supporting the tubercle. The lower premolars and sectorial have each two fangs, there being none truly answering to the first above : the anterior root of the lower (p. 1) sectorial tooth is very strongly developed in the great extinct Cave-Hy\u00e6na.\n3___3\nThe deciduous teeth consist of ; \u2014i. -\u2014->\nO \u00fc\n1 \u2014 1\t3\u20143\nc. i\u2014j, m.\t-g, = 28. The figure of the\nskull of the young Hy\u00e6na crocuta in the posthumous edition of the \u201c Ossemens Fossiles,\u201d 8vo. 1836, pi. 190, fig. 3, shows that stage when the correspondence with the formula of the genus Felis is completed by the appearance, in the upper jaw, of a small premolar in the interspace between the canine and first molar of the deciduous series : but this appearance is due to the apex of the first permanent premolar which cuts the gum before any of the normal deciduous teeth are shed : whether it is preceded, as in the dog, by a deciduous germ-tooth in the f\u0153tus, I know not. The first normal deciduous molar is two-fanged, and has a more compressed and consequently more carnivorous crown than that of the second permanent premolar by which it is succeeded. The second deciduous molar is the sectorial tooth : the inner tubercle is continued from the base of the middle lobe, and thus resembles the permanent sectorial of the Glutton (Gulo) and many other Mustelid\u00e6 ; the deciduous tubercular molar is relatively larger than in the adult Hy\u00e6na, and offers another feature of resemblance to the permanent dentition of the Glutton. It is also worthy of remark that the exterior incisor of the upper jaw is not only absolutely, but relatively smaller in the immature than in the adult dentition of the hy\u00e6na, and again illustrates the resemblance to the more common type of dentition in the Carnivora.\nThe first and second deciduous molars below have more compressed conical crowns than their successors : the third deciduous molar is the sectorial tooth, and, again, as\nin Gulo, has a better developed hinder tubercle than the permanent sectorial ; it is not displaced by this tooth, but, as in other Carnivora, by a premolar of more simple character. The permanent sectorial is developed posteriorly, and rises, like other true molars, without displacing a deciduous predecessor.\nThe permanent dentition of the Hy\u00e6na, as of other genera or families of the Carnivora, assumes those characteristics which adapt it for the peculiar food and habits of the adult, and mark the deviation from the common type, which always accompanies the progress to maturity. The most characteristic modification of this dentition is the great size and strength of the molars as compared with the canines, and more especially the thick and strong conical crowns of the second and third premolars in both jaws, the base of the cone being belted by a strong ridge which defends the subjacent gum.* This form of tooth is especially adapted for gnawing and breaking bones, and the whole cranium has its shape modified by the enormous development of the muscles which work the jaws and teeth in this operation.f Adapted to obtain its food from the coarser parts of animals which are left by the nobler beasts of prey, the hy\u00e6na chiefly seeks the dead carcass, and bears the same relation to the lion which the vulture does to the eagle. In consequence of the quantity of bones which enter into its food, the excrements consist of solid balls of a yellowish white colour, and of a compact earthy fracture. Such specimens of the substance, known in the old Materia Medica by the name of \u201c album gr\u00e6cum,\u201d were discovered by Dr. Buckland in the celebrated ossiferous cavern at Kirkdale. They were recognised at first sight by the keeper of a menagerie, to whom they were shown, as resembling both in form and appearance the foeces of the spotted Hy\u00e6na; and, being analysed by Dr. Wollaston, were found to be composed of the ingredients that might be expected in foecal matter derived from bones, viz. phosphate of lime, carbonate of lime, and a very small proportion of the triple phosphate of ammonia and magnesia. This discovery of the coprolites of the hy\u00e6na formed, perhaps, the strongest of the links in that chain of evidence by which Dr. Buckland proved that the cave at Kirkdale, in Yorkshire, had been, during a long succession of years, inhabited as a den by hyaenas, and that they dragged into its recesses the other animal bodies, whose remains, splintered and bearing marks of the teeth of the hy\u00e6na, were found mixed indiscriminately with their own.\n* An eminent civil engineer, to whom I showed the jaw of a hy\u00e6na, observed that the strong conical tooth, with its basal ridge, was a perfect model of a hammer for breaking stones for roads.\nf \u201c The strength of the hy\u00e6na\u2019s jaw is such that, in attacking a dog, he begins by biting off his leg at a single snap.\u201d Buckland, \u201c Keliqui\u00e6 Diluvian\u00e6,\u201d p. 23.","page":912},{"file":"p0913.txt","language":"en","ocr_en":"TEETH.\n913\nThe dentition of the Weasel tribe (Muste-lidce) is illustrated (in fig. 580, IV.) by that of the Otter, Mustela Lutra of Linn\u00e6us, and which is essentially a great aquatic Weasel or\ng g J_______J\nPolecat; its dental formula is i -\u2014-, c. 7\u2014r, 4\u20144\t1\u2014]\nP- tn. -______^ : = 36. In the Martin cats\n(Mustela martes, L.), the little homotype of p. 1 above is present in the lower jaw ; in the bloodthirsty stoats and weasels, p. 1 is absent in both jaws ; as it is likewise in the great sea-otter (.Enhydra), in which also the two middle incisors are wanting in the lower jaw. In this animal the second premolar (p. 3) has a strong obtuse conical crown, double the size of that ofp.2; the third premolar (p. 4) is more than twice the size of p. 3, and represents the upper carnassial or sectorial strangely modified ; the two lobes of the blade being hemispheric tubercles. The last tooth, m. 1, has a larger crown than the sectorial, and is of a similar broad crushing form. In the lower jaw the molar series are not separated by any interspace: the first and second premolars have oblique obtuse conical crowns. The third premolar (p. 4) is more than twice the size of the second (p. 3) and supports a large anterior hemispheric protuberance with a small internal tubercle and a posterior basal ridge. The first true molar has an oblong quadrate crown with an anterior small tubercle, a larger and more prominent inner one, and the rest of the broad horizontal surface undulating, The second true molar has a transversely elliptical crown depressed in the centre. When the teeth are in apposition, the anterior third of the first true molar below is applied to the inner tubercle of the last premolar above ; the rest of its crown plays upon that of its homotype, the first true molar in the upper jaw, leaving a small part of that tooth to receive the appulse of the second true molar below, which has no corresponding tooth in the upper jaw.\nThe Mustelidce present great constancy in regard to the number of their true molar teeth; with one exception, the Ratel (Melli* vora), in which m. 2 is absent below, they have one true molar on each side of the upper jaw, and two on each side of the lower jaw; the second of these has always a broad tubercular crown, like the one above. The upper true molar is supported by one inner, and sometimes by one (Putorius, Gido), sometimes two (Mustela, Lutra, Melphilis), outer fangs. The second true molar below is also tubercular, but has a single fang. The crown of the first true molar below offers many gradations from the sectorial type, as manifested in Putorius and Gulo, to the tubercular type, as in the Taira, Ratel, and sea-otter. The principal varieties occur, as' usual, in the comparatively less important premolars : in the Martins and Gluttons, they are as numerous as in the dog ; the first, in both jaws, being implanted by a single fang ; the rest by two, with the exception of\nVOL. IV.\nthe last above, which has three roots. In the otter, we find the first premolar removed from the lower jaw ; and the second (now the first) shows its true homology by its double implantation, as well as by the position of its crown behind the first in the upper jaw (p. 1). In the Stoats, Skunks, and Ratels, the premolar series is further reduced by the loss of the anterior tooth (p. 1) in both jaws, and by the diminution of the size of p. 2, which thus becomes the first in both jaws, and which is also now implanted by a single fang. In a South American Skunk, the second premolar disappears in the upper jaw, leaving there only the homologues of the third and fourth of the typical formula, p. 4 being always the sectorial in the Mustelidce, as in other terrestrial Carnivora. This tooth, under all its modifications, retains the blade with the lobe, corresponding to the middle one in the feline sectorial, generally well developed and sharp-pointed ; the differences are principally manifested by the proportions of the inner tubercle, and the relative size of the third root supporting it. But the upper sectorial, being a premolar, and therefore requiring less modification of the crown to adapt it for its special functions, manifests a more limited extent of variety than the lower sectorial, which, being a true molar, requires greater modification of the typical form of its crown to fit it for playing upon the sectorial blade of p. 4 above,\nMelid\u0153. In this sub-family I comprise the European Badger (Meles), the Indian Badger (Arctonyx), and the American Badger ( Taxidea) ; which, with respect to their dentition, stand at the opposite extreme of the Mustelidce to that occupied by the predaceous Weasel, and manifest the most tuberculate and omnivorous character of the teeth. The ,\t, .\t. 3\u20143\t1\u20141\t3\u20143\nformula 19:-*. 3^3: 0.\t1 P- 5^4, !\n1^1\nVI. : = 30.\nThe canines are strongly developed, well pointed, with a posterior trenchant edge ; they are more compressed in Arctonyx than in Meles. The first lower premolar (p. 1) is very small, single-fanged, and, generally, soon* lost. The first above, corresponding with the second in the dog, is also small, and implanted by two connate fangs. The second upper premolar (p. 3) has a larger, but simple, sub-compressed conical crown, and is implanted by two fangs : the third (p. 4) repeats the form of the second on a larger scale, with a better developed posterior talon, and with the addition of a tri-tuberculate low flat lobe, which is supported by a third fang : the outer pointed and more produced part of this tooth represents the blade of the sectorial tooth and the entire crown of the antecedent premolars. The true molar in Meles (m. ]) is of enormous size compared with that of any of the preceding Carnivora : it has three external tubercles, and an extensive horizontal surface traversed longitudinally by a low\n3 N","page":913},{"file":"p0914.txt","language":"en","ocr_en":"TEETH.\n914\nridge, and bounded by an internal belt, the cingulum of Illiger: this tooth has a similarly shaped, but relatively smaller, crown in Arc-tonyx.* The second premolar below (p. 2) is commonly the first, through the early loss of the minute one in front ; its fangs are usually connate, as in its homotype above. The third and fourth premolars slightly increase in size, have simple compressed conical crowns, and two fangs each. The first true molar below (\u00bb/. 1) now retains little of its sectorial character, the blade being represented only by the two anterior small, compressed pointed lobes; behind these, the crown expands into an oval grinding surface, narrower in Arctonyx than in Meles, supporting three tubercles and a posterior tuberculate ridge : it has generally two principal roots and a small intermediate accessory fang, as in the otter. The second molar (m. 2), which terminates the series below, is of small size, and has a rounded flat crown, depressed in the centre, and with two small external tubercles; its two short fangs are connate. In the Labrador Badger, the last premolar has a larger relative size, the part corresponding with the blade of the sectorial, is sharper and more produced, and the internal tubercle has two lobes; the succeeding molar tooth is reduced in size, and its crown presents a triangular form. The first true molar below has its sectorial lobes better developed : these differences give the North American badgers a more carnivorous character than is manifested by the Indian or European species.\nSub-Ursid\u0153.\u2014In other allied genera, which, like the badgers, have been grouped, on account of the plantigrade structure of their feet, with the bears, a progressive approximation is made to the type of the dentition of the Ursine species. The first true molar below soon loses all its sectorial modification, and acquires its true tubercular character : and the last premolar above becomes more directly and completely opposed to its homotype in the lower jaw. The Racoon ( Procyon f ) and the Coati (Nasua) present good examples of these transitional modifications ; they have the complete number of premolar teeth, the\n3___3 j____1\t4,__4\ndental formula being, i. c. ^p. ^\n2___2\nvi. ~^ : = 40. The development of the in-\nner part of the crown of the last upper premolar, which constitutes the tubercie of the sectorial tooth, now produces two tubercles on a level with the outer ones which represent the blade; and the opposite premolar below {p. 4), which is the true homotype of the modified sectorial above, begins to acquire a marked increase of breadth and accessory basal tubercles. All the lower premolars, as well as the true molars, have two fangs; the three first premolars above have two fangs, the fourth has three, like the two true molars above.\nThe dental formula of the Indian Bentu-\n* See Odontography, pi. 128,fig. 13, m. 1.\nf lb. pi. 129,/^. 7. t lb. pigs. 8\u201413.\nrong (Arcticlis) and Kinkajou ('Cercolcptes) is\n. 3\u20143 3\u20143\u2019\n1\u2014I =!\u2019*\u2022\n3\u20143\n3\u20143\n, m. r\n2\u20142\n'\u25a0 2\u20142\n: = 36.\nPhocid\u0153. \u2014 We have seen a tendency to deviate from the ferine number of the incisors in the most aquatic and piscivorous of the Musteline quadrupeds, viz. the sea-otter (Enhydra), in which species the two middle incisors of the lower jaw are not developed in the permanent dentition. In the family of true seals, the incisive formula is further reduced, in some species even to zero in the\n3__3\nlower jaw, and it never exceeds -\u2014-. All\nthe Phocid\u0153 possess powerful canines ; only in the aberrant walrus ( Tnchechus) are they absent in the lower jaw, but this is compensated by the singular excess of development which they manifest in the upper jaw. In the pinnigrade, as in the plantigrade, family of Carnivores we find the teeth which correspond to true molars more numerous than in the digitigrade species, and even occasionally rising to the typical number, three on each side ; but this, in the seals, is manifested in the upper and not, as in the bears, in the lower jaw. The entire molar series usually includes five, rarely six teeth on each s:de of the upper jaw, and five on each side of the lower jaw, with crowns, which vary little in size or form in the same individual ; they are supported in some genera, as the Eared Seals (Otari\u0153) and Elephant Seals (Cystophora*), by a single fang ; in other genera f by two fangs, which are usually connate in the first or second teeth ; the fang or fangs of both incisors, canines and molars, are always remarkable for their thickness, which commonly surpasses the longest diameter of the crown. The crowns are most commonly compressed, conical, more or less pointed, with the \u201c cingulum \u201d and the anterior and posterior basal tubercles more or less developed; in a few of the largest species they are simple and obtuse, and particularly so in the walrus, in which the molar teeth are reduced to a smaller number than in the true seals.J In these the line of demarcation between the true and false molars is very indefinitely indicated by characters of form or position ; but, according to the instances in which a deciduous dentition has been observed, the first three permanent molars in both jaws succeed and displace the same number of milk molars, and are consequently premolars ; occasionally, in the seals with two-rooted molars, the more simple character of the premolar teeth is manifested by their fangs being connate, and in the Stenorhynchus serri-dens the more complex character of the true molars is manifested in the crown. There is no special modification of the crown of any tooth by which it can merit the name of a\n* Odontography, pi. 132, fiq. 7. f lb. figs. 1\u20144.\n\u00ce The relation of Trichechus to the Phocid\u0153 is analogous to that of Machairodus to the Felid\u0153, and also, in the simplification of the molars, to that of Proteles to Canid\u0153.","page":914},{"file":"p0915.txt","language":"en","ocr_en":"TEETH.\n915\n\u201csectorial\u201d or \u201c carnassial ; \u201d but we may point with certainty to the third molar above and the fourth below as answering to those teeth which manifest the sectorial character in the terrestrial Carnivora.\nThe coadaptation of the crowns of the upper and lower teeth is more completely alternate than in any of the terrestrial Carnivora, the lower tooth always passing into the interspace anterior to its fellow in the upper jaw. In the genus Phoca proper (Ca-locephalus, Cuv.) typified by the common seal\n3___3\n(Pfi, vitulina), the dental formula is, i. \u2014\u2014-,\n---a\nI__i 3______3 g_____2\nC. j\u2014p. 3__3, to. : = 34. The forms\nand proportions of these teeth are shown in PI. 132, fig. 1., of my \u201cOdontography.\u201d The first tooth above and below presents a complete confluence of the fangs ; they are separated from the second above ; but below they sometimes do not become free before the fourth, and sometimes the two roots are distinct in the third and second molars. In the Phoca anellata Nills., the principal cusp of the molar teeth is complicated with anterior and posterior smaller cusps, sometimes one in number in the upper molars ; the anterior accessory cusp is sometimes wanting in the first, and is rudimentary in the rest ; but usually there are two small cusps behind the principal one, and in the three or four posterior molars in the lower jaw there are sometimes two small cusps before and two behind the principal one.*\nIn the Phoca caspica the upper molars have commonly one accessory cusp before and one behind the principal lobe; the lower molars have one accessory cusp before and two behind.\nIn the Phoca grcenlandica the upper molars have no anterior basal cusp and only one behind ; the lower molars have two cusps behind and one in front, except the first, which resembles that above, and, like it, has connate fangs.\nThe condition of the molar teeth is nearly the same in the Phoca barbata, but the crowns are rather thicker and stronger, and the three middle ones above have two posterior basal cusps feebly indicated, the same being more strongly marked in the four last molars below.\nThe following genera of seals with double-rooted molars (Pelagias and Stenorhynchus') have four incisors above as well as below, i. e.\n2-2\n2\u20142'\nAn upper view of the molar teeth in\nthe Hooded Seal of the Mediterranean (Pc/a-gius monachus) is given in my Odontography, PI. 132.fig. 3., as when they are worn down in an old specimen ; the crowns are thick, obtuse, sub-compressed, with a well developed\n* Nillson, in Wiegmann\u2019s Archiv. 1841, 313. I notice these varieties of the crown, in connection with analogous ones in the fangs of the teeth of the same species, to show the inadequacy of such characters as marks of subgeneric distinction.\ncingulum, a principal lobe and an anterior and posterior accessory basal lobule ; the fangs are connate in the first tooth both above and below.\nThe allied sub-genus (Ommatophoca) of seals of the southern hemisphere has six molar teeth on each side of the upper, and five on each side of the lower jaw, with the principal lobe of the crown more incurved. The two first molars above are closely approximated, but this may prove to be a variety.\nIn the Stenorhynchus the jaws are more slender and produced, and the molar teeth are remarkable for the long and slender shape of the principal lobe, and of the accessory basal cusps. The incisors have sharp conical recurved crowns, like the canines, and the external ones in the upper jaw are intermediate in size between the canines and the middle incisors.\nIn the Stenorhynchus leptonyx each molar tooth in both jaws is trilobed, the anterior and posterior accessory curving towards the principal one, which is bent slightly backwards ; all the divisions are sharp-pointed, and the crown of each molar thus resembles the trident or fishing-spear ; the two fangs of the first molar in both jaws are connate. In Stenorhynchus serridens the three anterior molars on each side of both jaws are four-lobed, there being one anterior and two posterior accessory lobes ; the remaining posterior molars (true molars) are five-lobed, the principal cusp having one small lobe in front, and three developed from its posterior margin ; the summits of the lobes are obtuse, and the posterior ones are recurved like the principal lobe. Sometimes the third molar below has three instead of two posterior accessory lobes. Occasionally, also, the second, as well as the first molar above, has it fangs connate ; but the essentially duplex nature of the seemingly single fang, which is unfailingly manifested within by the double pulp-cavity, is always outwardly indicated by the median longitudinal opposite indentations of the implanted base. These slight and unessential varieties, presented by the specimens of the Saw-toothed Sterrink {Stenorhynchus serridens) brought home by the enterprising Naturalist of Sir J. Ross\u2019s Antarctic expedition, accord with the analogous varieties noticed by the best observers of the seals of our neighbouring seas, as, for example, Nillson.\nThe Grey Seal {Haiich\u0153rus gryphus) of our own seas begins, by the extension of the connate condition of the two roots through a greater proportion of the molar series, to manifest a transition to the family of seals with true single-rooted molars ; the formula\nof this genus is, i. ^ c.\tP\u2022 ^\t^\n2\u20142\t1\u2014I * 3\u20143\n2\u20142\nm' \u00d6\u2014\u00e0 : ^ The ^our middle upper incisors are close set, with pointed recurved crowns ; the lateral ones are much larger and laniariform : the canines have moderate crowns, with a sharp ridge before and behind. The\n3 N 2","page":915},{"file":"p0916.txt","language":"en","ocr_en":"916\nTEETH.\ncrowns of the molar teeth are conical, subcompressed longitudinally and finely grooved, with an anterior and posterior edge ; those below have generally a slight notch at the fore and back part of the base. The first molars, both above and below, are the smallest, with a simple crown and a single ventricose fang ; the second and third above, and the second, third, and fourth below, have two connate roots ; the two roots are commonly distinct in the remaining posterior molars : all the roots are very thick.\nIn the genus Otaria the dental formula is,\n2\u20142\u2019\nc.\n1\u20141\n1\u20141\u2019\nV\u2022\n3\u20143\n3\u20143\u2019\n\u2014 = 36. The 2\u20142\ntwo middle upper incisors are small, sub-compressed, with the crown transversely notched ; the simple crowns of the four incisors below fit into these notches : the outer incisors above are much larger, with a long pointed conical crown, like a small canine. The true canine is twice as large as the adjoining incisor, and is rather less recurved. The molars have eaeh a single fang ; the crown is conical, subcompressed, pointed ; in the two last recurved, with a basal ridge or \u201c cingulum,\u201d broadest within : but, in the Otaria jubata, the molars have a pointed cusp developed from the forepart, and in the last two molars also from the back part of the crown. In some species, as the Otaria lobata (Phoca lobata, Fischer), the single molar is not developed in the upper jaw, and the outer incisors above are not so large : in this species a thick plicated cingulum belts the base of each molar and developes a small tubercle from its fore-part in the molars of the lower jaw j the crown of the last molar above is notched.\nIn the great proboscidian and hooded Seals (Cystophora), the incisors and canines still more predominate in size over the molars ; but the incisors are reduced in number, the\n-\t,\t,\t\u2022\t. 2\u20142\t1\u20141\t3\u20143\nformula here is: i. ^ c. y\u2014y, p. ^\n2__2\nm. -\u2014-: = 30. All the molars are single-\nid ~~~~ id\nrooted, and all the incisors are laniariform. The two middle incisors above and the two below are nearly equal ; the outer incisors above are larger. The canines are still more formidable, especially in the males ; the curved root is thick and subquadrate. The crowns of the molar teeth are short, sub-compressed, obtuse ; sometimes terminated by a knob and defined by a constriction or neck from the fang ; the last is the smallest.\nIn the Walrus (Tnchechus rosmarus), the normal incisive formula is transitorily represented in the very young animal, which has three teeth in each intermaxillary bone and two on each side of the fore-part of the lower jaw ; they soon disappear, except the outer pair above, which remain close to the intermaxillary suture, on the inner side of the sockets of the enormous canines, and seem to commence the series of small and simple molars which they resemble in size and form. In the adult there are usually three molars or\npremolars on each side above, behind the permanent incisor, and four similar teeth on each side of the lower jaw ; the anterior one passing into the interspace between the upper incisor and the first molar, and therefore being the homotype of the molar. In a young walrus\u2019s skull with canine tusks eight inches long, I have seen a fourth upper molar, (fifth including the incisor), of very small size, about a line in breadth, lodged in a shallow fossa of the jaw, behind the three persistent molars. The crowns of these teeth must be almost on a level with the gums in the recent head ; they' are very obtuse and worn obliquely from above down to the inner border of their base. The molars of the lower jaw are rather narrower from side to side than those above, and are convex or worn upon their outer side. Each molar has a short, thick, simple and solid root.\nThe canines are developed only in the upper jaw, but are of enormous size, descending and projecting from the mouth, like tusks, slightly inclined outwards and bent backwards ; they present an oval transverse section, with a shallow longitudinal groove along the inner side, and one or two narrower longitudinal impressions upon the outer side ; the base of the canine is widely open, its growth being uninterrupted.\nThe food of the walrus consists of seaweed and bivalves ; the molars are well adapted to break and crush shells ; and fragments of a species of Mya have been found, with pounded sea-weed, in the stomach. The canine tusks serve as weapons of offence and defence, and to aid the animal in mounting and clambering over blocks of ice. For their composition and microscopic structure I must refer to my \u201c Odontography,\u201d p. 511. et seq.\nThe precise determination of the teeth in the walrus and some other kinds of seals, still awaits the opportunity of examining very young specimens with the deciduous series, which is very early lost. When the clew is afforded by the opportunity of studying the development and succession of the teeth, it infallibly conducts us to the true knowledge of the nature, both of the teeth which are retained, and of those that are wanting to complete the typical number. We have availed ourselves of this in deciphering the much modified dentition of the genus Felis; and the same clew will guide us to a similar satisfactory knowledge of the nature and homologies of the teeth in the human species. The discovery, by the great poet G\u00f6the, of the limits of the premaxillary bone in man leads to the determination of the incisors, which are reduced to two on each side of both jaws : the contiguous tooth shows by its shape, as well as position, that it is the canine, and the characters of size and shape have also served to divide the remaining five teeth in each lateral series into two bicuspids and three molars. In this instance, as in the dentition of the bear, the secondary characters conform with the essential ones. * But since we have seen of how little value shape or size are, in the order Carnivora, in the deter\u00ab-","page":916},{"file":"p0917.txt","language":"en","ocr_en":"TEETH.\n917\ninitiation of the exact homologies of the teeth, it is satisfactory to know that the more constant and important character of development gives the requisite certitude as to the nature of the so-called bicuspids in the human subject. In fig. 581., the condition of the\nFig. 584.\nDeciduous and permanent teeth of a Child (Homo).\nteeth is shown in the jaws of a child of about six years of age. The two incisors on each side (di.) are followed by a canine, dc., and this by three teeth having crowns resembling those of the three molar teeth of the adult. In fact, the last of the three is the first of the permanent molars ; it has pushed through the gum, like the two molars which are in advance of it, without displacing any previous tooth, and the substance of the jaw contains no germ of any tooth destined to displace it : it is therefore, by this character of its development, a true molar, and the germs of the permanent teeth, which are exposed in the substance of the jaw between the diverging fangs of the molars, d. 3 and d. 4, prove those molars to be tempor\u00e4r}', destined to be replaced, and prove also that the teeth about to displace them are premolars. According, therefore, to the rule previously laid down, we count the permanent molar in place the first of its series (in. 1), and the adjoining premolar as the last of its series, and consequently the fourth of the typical dentition, or p. 4.\nWe are thus enabled, with the same scientific certainty as that whereby we recognise in the middle toe of the foot the homologue of that great digit which forms the whole foot and is encased by the hoof in the horse, to point to p. 4, or the second bicuspid in the upper jaw, and to m. 1, or the first molar in the lower jaw of man, as the homologues of the great carnassial teeth of the lion and tiger. We also conclude that the teeth which are wanting in man to complete the typical molar series, are the first and second\npremolars, the homologues of those marked p. 1 and p. 2 in the bear. The characteristic shortening of the maxillary bones required this diminution of the number of their teeth, as well as of their size, and of the canines more especially ; and the still greater curtailment of the premaxillary bone is attended with a diminished number and an altered position of the incisors. One sees, indeed, in the carnivorous series, that a corresponding decrease in the number of the premolars is concomitant with the shortening of the jaws. Already in the Mustelul\u0153, (fig. 580., IV), p. 1 below is abrogated; in Felis also above, with the further loss of p. 2 in the lower jaw ; the true molars being correspondingly reduced in these strictly flesh-eating animals, but taken away from the back part of their series.\nIf we wrere desirous of further testing the soundness of the foregoing conclusions as to the nature of the teeth absent in the reduced dental formula of man, we ought to trace the mode in which the type is progressively resumed in descending from man through the order most nearly allied to our own.\nThrough a considerable part of the Qua-drumanous series, e. g. in all the Old World genera above the Lemurs, the same number and kinds of teeth are present as in man ; the first deviation being the disproportionate size of the canines and the concomitant break or \u201cdiastema\u201d in the dental series for the reception of their crowns when the mouth is shut. This is manifested in both the Chimpanzees and Orangs, together with a sexual difference in the proportions of the canine teeth.\nAs the precise characteristics of the human dentition are best demonstrated by comparison with that brute species which is most nearly allied to Man, and makes the first step in the descending scale, I here subjoin the details of such a comparison, which is the more required since it is not touched upon in the article Quadrumana, and will be the more acceptable as one of its subjects is a species of Chimpanzee ( Troglodytes Gorilla) *, unknown to science when that article was written, and which, so far as its organisation is known, is more anthropoid than even the docile and smaller species of Chimpanzee (Troglodytes niger). A side view of the teeth of a male, full-grown, but not aged, specimen of the great Chimpanzee is given of the natural size in fig. 585., and a view of the working surface of the whole series of the upper jaw in fig. 586. This dentition, though in all its principal characters strictly quadrumanous, yet, in the\n* Drs. Savage and Wyman, Boston Journal of Natural History, 1847 ; Owen, Transactions of the Zoological Society, vol. iii. p. 881 (February, 1848). M. F. Cuvier has not given a figure of the dentition of any species of Chimpanzee (Troglodytes). Believing with his brother, that the Orang (Pithecus, Geoffr.) made the nearest approach to man, the dentition of an immature Pithecus Wurmbii with one of the characteristically large permanent molars (m. 1) in place, immediately follows the plate of the human dentition in the \u201c Dents des Mammif\u00e8res,\u201d 8vo. pis. i. & ii.\n3 n 3","page":917},{"file":"p0918.txt","language":"en","ocr_en":"918\nTEETH.\nFi\". 585.\n\nDentition of adult male, Troglodytes Gorilla. (Natural size.')\nFl;. 58G.\nDentition of upper jaw, Troglodytes Gorilla, adult male. (Natural size.)\ni\n1","page":918},{"file":"p0919.txt","language":"en","ocr_en":"TEETH.\n919\nminor particulars in which it differs from the dentition of the Orang, approaches nearer the human type. In the upper jaw the middle incisors (fig. 586, i. 1) are smaller, the lateral ones (ib. i. 2) larger than those of the Orang* ; they are thus more nearly equal to each other; nevertheless the proportional superiority of the middle pair is much greater than in Man, and the proportional size of the four incisors both to the entire skull and to the other teeth is greater. Each incisor has a prominent posterior basal ridge, and the outer angle of the lateral incisors, i. 2, is rounded off as in the Orang. The incisors incline forwards from the vertical line as much as in the great Orang. Thus the characteristics of the human incisors are, in addition to their true incisive wedge-like form, their near equality\nteeth \u201d *, when the mouth is closed, is applicable only to the female, and does not distinguish the Chimpanzees from the Orangs. In the male of the smaller Chimpanzee (Troglodytes niger) the upper canine is conical, pointed, but more compressed than in the Orang, and with a sharper posterior edge ; convex anteriorly, becoming flatter at the posterior half of the outer surface, and concave on the corresponding part of the inner surface, which is traversed by a shallow longitudinal impression ; a feeble longitudinal rising and a second linear impression divide this from the convex anterior surface, which also bears a longitudinal groove at the base of the crown. The canine is rather more than twice the size of that in the female. In the male Gorilla {figs. 585, 586.), the crown of the canine is\nFig. 587\nDentition of adult female, Troglodytes Gorilla. (Natural size.')\nof size, their vertical or nearly vertical position, and small relative size to the other teeth and to the entire skull. The diastema between the incisors and the canine on each side is as well marked in the male Chimpanzee as in the male Orang.f The crown of the canine (ib. c.), passing outside the interspace between the lower canine and premolar, extends in the male Troglodytes Gorilla a little below the alveolar border of the under jaw when the mouth is shut ; the upper canine of the male Troglodytes niger likewise projects a little below that border ; the seventh character, therefore, which I had formerly assigned to the genus, \u201c apices of canines lodged in intervals of the opposite\n* Compare fig. 586. with pi. xxxii. (Pithecus Wurmbii) and pi. xxxiv. {Pith. Mono), in vol. ii. Zool. Trans.\nf Compare y\u00ab?. 586. with pi. xxxii. {Pith. Wurm-bii) in vol. ii. Zool. Trans.\nmore inclined outwards : the anterior groove on the inner surface of the^crown is deeper ; the posterior groove is continued lower down upon the fang, and the ridge between the two grooves is more prominent than in the Troglodytes niger. Both premolars (fig. 586. p. 3 and p. 4) are bicuspid ; the outer cusp of the first and the inner cusp of the second being the largest, and the first premolar consequently appearing the largest on an external view (fig. 585.). The difference is well marked in the female (fig. 587, p. 3, p. 4). The anterior external angle of the first premolar is not produced as in the Orang, which in this respect makes a marked approach to the lower Qua-drumana. In Man, where the outer curve of the premolar part of the dental series is greater than the inner one, the outer cusps of both premolars are the largest ; the alternating superiority of size in the Chimpanzee accords * Zool. Trans, vol. i. p. 372.\n3 n 4","page":919},{"file":"p0920.txt","language":"en","ocr_en":"TEETH.\n920\nwith, and contributes to, the straight line which the canine and premolars form with the true molars.\nThe true molars (fig. 586., m. l,m.2, m. 3) are quadricuspid, relatively larger in comparison with the bicuspids than in the Orang. In the first and second molars of both species of Chimpanzee a low ridge connects the antero-internal with the postero-external cusp, crossing the crown obliquely, as in Man. There is a feeble indication of the same ridge in the unworn molars of the Orang ; but the four principal cusps are much less distinct, and the whole grinding surface is flatter and more wrinkled than in the Chimpanzee. In the Troglodytes niger the last molar is the smallest, owing to the inferior development of the two hinder cusps, and the oblique connecting ridge is feebly marked. In the Troglodytes Gorilla this ridge is as well developed as in the other molars, but is more transverse in position ; and the crown of m. 3 is equal in size to that of m. 1 or m. 2, having the posterior outer cusp, and particularly the posterior inner cusp, more distinctly developed than in the Troglodytes niger. The repetition of the strong sigmoid curves which the unworn prominences of the first and second true molars present in Man, is a very significant indication of the near affinity of the Chimpanzee as compared with the approach made by the Orangs or any of the inferior Quadrumajia, in which the four cusps of the true molars rise distinct and independently of each other. A low ridge girts the base of the antero-internal cusp of each of the upper true molars in the male Chimpanzee: it is less marked in the female. The premolars as well as molars are severally implanted by one internal and two external fangs, diverging but curving towards each other at their ends as if grasping the substance of the jaw. I have found the two outer fangs of the second premolar connate in one female specimen of the Troglodytes niger. In no variety of the human species are the premolars normally implanted by three fangs ; at most the root is bifid, and the outer and inner divisions of the root are commonly connate. It is only in the black varieties, and more particularly that race inhabiting Australia, that\nI have found the wisdom tooth, m. 3, with three fangs as a general rule ; and the two outer ones are more or less confluent.\nIn the lower jaw of the great Chimpanzee the lateral incisors are broader than the middle ones, although they are smaller relatively than in the Troglodytes niger ; they are larger and less vertically implanted than in Man. The lower canines are two inches and a half in length, including the root ; the enamelled crown is an inch and a quarter in length, and nearly an inch across the base; it is conical and trihedral ; the outer and anterior surface is convex, the other two surfaces are flattened or subconcave, and converging to an almost trenchant edge directed inwards and backwards ; a ridge separates the convex from the antero-internal flat surface ; both this and the posterior surface show slight traces of a longitudinal rising at their middle part. The lower canine of the male shows the same relative superiority of size as the upper one compared with that in the female in both species of Chimpanzee. The canine almost touches the incisor, but is separated by a diastema one line and a half broad from the first premolar. This tooth (p. 3) is larger externally than the second premolar, and is three times the size of the human first premolar (p. 3) ; it has a subtrihedral crown, with the anterior and outer angle produced forwards, slightly indicating the peculiar feature of the same tooth in the Baboons, but in a less degree than in the Orang. The summit of the crown of p. 3 terminates in two sharp trihedral cusps, the outer one rising highest, and the second cusp being feebly indicated on the ridge extending from the inner side of the first ; the crown has, also, a thick ridge at the inner and posterior part of its base. The second premolar (p. 4) has a subquadrate crown, with the two cusps developed from its anterior half, and a third smaller one from the inner angle of the posterior ridge. Each lower premolar is implanted by two antero-posteriorly compressed divergent fangs, one in front of the other, the anterior fang being the largest. The three true molars are equal in size in the Troglodytes Gorilla ; in the Troglodytes niger (fig. 588.) the first (m. 1) is a little larger than the last (???. 3), which is the\nDental series, lower jaw, adult male, Troglodytes niger. (Natural Size.)","page":920},{"file":"p0921.txt","language":"en","ocr_en":"TEETH.\t921\nonly molar in the smaller Chimpanzee as large as the corresponding tooth in the black varieties of the human subject *, in most of which, especially the Australians, the true molars attain larger dimensions than in the yellow or white races. The four principal cusps, especially the two inner ones, of the first molar of both species of Chimpanzee are more pointed and prolonged than in Man ; a fifth small cusp is developed behind the outer pair, as in the Orangs and the Gibbons, but is less than that in Man. The same additional cusp is present in the second molar, which is seldom seen in Man. The crucial groove on the grinding surface is much less distinct than in Man, not being continued across the ridge connecting the anterior pair of cusps in the Chimpanzee. The crown of the third molar is longer antero-posteriorly from the greater development of the fifth posterior cusp, which, however, is rudimental in comparison with that in the Semnopitheques and Macaques. All the three true molars are supported by two distinct and well developed antero-posteriorly compressed divergent fangs, longitudinally excavated on the sides turned towards each other ; in the white and yellow races of the human subject these fangs are usually connate in to. 3, and sometimes also in m. 2. The molar series in both species of Chimpanzee forms a straight line, with a slight tendency in the upper jaw to bend in the opposite direction to the well-marked curve which the same series describes in the human subject.\nThis difference of arrangement, with the more complex implantation of the premolars, the proportionally larger size of the incisors as compared with the molars ; the still greater relative magnitude of the canines ; and, above all, the sexual distinction in that respect, illustrated by figs. 585. 587., stamp the Chimpanzees most decisively with not merely specific but generic distinctive characters as compared with Man. For the teeth are fashioned in their shape and proportions in the dark recesses of their closed formative alveoli, and do not come into the sphere of operation of external modifying causes until the full size of the crowns has been acquired. The formidable natural weapons, with which the Creator has armed the powerful males of both species of Chimpanzee, form the compensation for the want of that psychical capacity to forge destructive instruments which has been reserved as the exclusive prerogative of Man. Both Chimpanzees and Orangs differ from the human subject in the order of the development of the permanent series of teeth ; the second molar (to. 2) comes into place before either of the premolars has cut the gum, and the last molar (to. 3) is acquired before the canine. We may well suppose that the larger grinders are earlier required by the frugivorous Chimpanzees and Orangs than by the higher organised omnivorous species with more numerous and varied resources, and probably one main condition of the earlier\ndevelopment of the canines and premolars in Man may be their smaller relative size.\nIn the South American Quadrumana, the number of teeth is increased to thirty-six (art. Quadrumana,Vo1. IV. p. 210.; Cebin\u0153*), by an addition of one tooth to the molar series on each side of both jaws. It might be concluded, \u00e0 priori, that as three is the typical number of true molars in the placental Mammalia with two sets of teeth, the additional tooth in the Cebin\u0153 would be a premolar, and form one step to the resumption of the normal number (four) of that kind of teeth. The proof of the accuracy of this inference is given by the state of the dentition in the young Cebus in fig. 589., which corresponds with that of the human child in fig. 584., i. e. the whole of the\nFig. 589.\nDeciduous and permanent teeth of Cebus.\ndeciduous dentition is retained, and the first true molar (to. 1 ) is in place on each side of both jaws. The germs of the other teeth of the permanent series are exposed in the upper jaw ; and the crown of a premolar is found above the third molar in place, as well as above the second and first. As regards number, therefore, the molar series, in Cebus, is intermediate between that of Mustela {fig. 580., IV.) and Felis (ib. V.) ; the little premolar p. i. in Mustela tells plainly enough which of the four is wanting to complete the typical number in the South American Monkey, and which is the additional premolar distinguishing its dental formula from that of the Old World monkeys and man. By reference to Prof. Vro-lik\u2019s article (Quadrumana) it will be seen that the eighth genus, including the little Marmoset monkeys (Hapale, Ouistiti), \u201c have only the same number of teeth as the monkeys\n4\t1\u20141\nof the Old World, viz. 32, i. \u00ff c. -\u2014m. 5___5\n-\u2014But the difference is much greater\nO---J\nthan this numerical conformity would intimate. In a young Jacchus penicillatus I find that there are three deciduous molars displaced by three premolars, as in the other South American Quadrumana, and that it is the last true molar, to. 3, the development of which is suppressed, not the preraolar p. 2, and thus these diminutive squirrel-like monkeys actually differ\n* The dental series seems, unluckily, not to have been complete in either of the skulls represented by the distinguished author of that able article (Jigs. 132, 133).\nBee my Odontography, pi. 119, fig. 2, m.","page":921},{"file":"p0922.txt","language":"en","ocr_en":"922\nTEETH.\nfrom the Old World Quadrumana more than the Cebid\u00e6 do ; i. e. they differ not only in having\nfour teeth (p. 2 \u2014j), which the monkeys of\nthe Old World do not possess, but also by\nwanting four teeth (in. 3 j |), which those\nmonkeys, as well as the Cebid\u00e6, actually have. It is thus that the investigation of the exact homologies of parts leads to a recognition of the true characters indicative of zoological affinity,\n3\u20143\nMost of the Lemurin\u0153 have p. ^m.\n3___3\n----, together with remarkable modifications\n3\u20143\t0\nof their incisive and canine teeth, of which an extreme example is shown in the pectinated tooth (fig. 556.) of the Galeopithecus. The inferior incisors slope forwards in all, and the canines also, which are contiguous to them, and very similar in shape. In the Chirogaleus these canines are entered as incisors in the dental formula of the genus ( Vol. IV. p. 215), and the laniariform premolar (p. 2) is entered as a canine : M. Vrolik also describes four teeth on each side of the upper jaw, and four on each side of the lower jaw, as true tuberculated molars. They have tuber-culated crowns, but the value of shape as a character is too small to permit our accepting so great an anomaly without the requisite proof of their order of development and succession.\nEven in the hoofed quadrupeds with toes in uneven number (PemsodactyUi), whose premolars, for the most part, repeat both the form and the complex structure of the true molars, such premolars are distinguished by the same character of development as those of the Artiodactyla, or Ungulates with toes in even number ; although in these the premolars are distinguished also by modifications of size and shape. The complex ridged and tuber-culate crowns of the second, third, and fourth grinders of the Rhinoceros, Hyrax (fig. 590.),\ntooth be determined, and its proper symbol applied to it.\nIn pi. 136, fig. 5, of my Odontography, the three posterior teeth of the almost uniform grinding series of the horse\u2019s dentition are thus proved to be the only ones entitled to the name of \u201c true molars and, if any one. should doubt the certainty of the rule of counting, by which the symbols, p. 4, p. 3, and p. 2, are applied to the three large anterior grinding teeth (ib. fig. 19), which are commonly the only premolars present in each lateral series of the horse\u2019s jaws, yet the occasional retention of the diminutive tooth,/). 1 (ib.^%. 6), would establish its accuracy, whether such tooth be regarded as the first of the deciduous series unusually long retained, or the unusually small and speedily lost successor (p. 1) of an abortive d 1.\nThe law of development, so beautiful for its instructiveness and constancy in the placental Diphyodonts, is here illustrated in the little Hyrax (fig. 591.), in which the d. 1 is\nFig. 591.\nDeciduous and permanent molars of the Hyrax.\nnormally developed and succeeded by a permanent p. 1, differing from the rest only by a graduated inferiority of size, which, in regard to the last premolar, ceases to be a distinction between it and the first true molar.\nThe elephant, which by its digital characters belongs to the odd-toed, or perissodactyle, group of Pachyderms, also resembles them in the close agreement in form and structure of the grinding teeth representing the premolars,\nFig. 590.\nMolar series, upper jaw (Hyrax).\nand horse, no more prove them to be true molars, than the trenchant shape of the lower carnassials of the lion proves them to be false molars. It is by development alone that the primary division of the series of grinding teeth can be established, and by that character only can the homologies of each individual\nwith those that answer to the true molars_of the Hyrax, Tapir, and Rhinoceros. The gigantic Proboscidian Pachyderms of Asia and Africa present, however, so many peculiarities of structure, as to have led to their being located in a particular family in the Systematic Mammalogies. And this seems to be justified","page":922},{"file":"p0923.txt","language":"en","ocr_en":"TEETH.\n293\nby no character more than by the singular seeming exception which they present to the Diphyodont rule which governs the dentition of other hoofed quadrupeds. In fact, the elephant, like the Dugong, sheds and replaces vertically only its incisors, which are also two in number, very long, and of constant growth, forming tusks, with an analogous sexual dif-erence in this respect in the female of the Asiatic species. The molars, also, are successively lost, are not vertically replaced, and are reduced finally to one on each side of both jaws, which is larger than any of its predecessors. These analogies are interesting and suggestive in connection with the other approximations in the \u201c Sirenia\u201d to the pa-chydermal type, which I have pointed out in the \u201c Proceedings of the Zoological Society.\u201d *\nThe dentition of the genus Elephas, the sole existing modification of the once numerous and varied Proboscidian family, includes two long tusks (fig. 592.), one in each of the Intermaxillary bones, and large and complex molars (ib. m. 3, 4, and 5) in both jaws : of the latter there is never more than one wholly, or two partially, in place and use on each side at any given time; for, like the molars of the Mastodons, the series is continually in progress of formation and destruction, of shedding and replacement ; and in the elephants all the grinders succeed one another like true molars horizontally, from behind forwards.\nThe total number of teeth developed in the 2\u20142 6\u20146\nelephant appears to be i. q ~q, m. g_g = 28.\nThe two large permanent tusks being preceded by two small deciduous ones, and the number of molar teeth which follow one another on each side of both jaws being at\n\u201c The socket of the permanent tusk in a new-born elephant, is a round cell about three lines in diameter, situated on the inner and posterior side of the aperture of the temporary socket. The permanent tusks cut the gum when about an inch in length, a\nFig. 592.\nleast six, of which the last three may, by analogy, be regarded as answering to the true molars of other Pachyderms. I have shown in my Odontography that : \u2014\n\u201c The deciduous tusk makes its appearance beyond the gum between the fifth and seventh month ; it rarely exceeds two inches in length, and is about a'third of an inch in diameter at its thickest part, where it protrudes from the socket ; the fang is solidified, and contracts to its termination, which is commonly a little bent, and is considerably absorbed by the time the tooth is shed, which takes place between the first and second year.f\n* 1838, p. 40.\tm \u201e ,\nf See Mr. Corse\u2019s \u201c Memoir on the Teeth of the Elephant,\u201d in Philosophical Transactions, 1799, p. 211 : a good figure of the deciduous tusk is given in plate 5.\nSection of cranium and tusk of the Elephant\nmonth or two, usually, after the milk-tusks are shed. At this period, according to Mr. Corse *, the permanent tusks are \u2018 black and ragged at the ends. When they become longer, and project beyond the lip, they soon are worn smooth bv the motion and friction of the trunk.\u2019 Their widely open base is fixed upon a conical pulp, which, with the capsule surrounding the base of the tusk and the socket, continues to increase in size and depth, obliterating all vestiges of that of the deciduous tusk, and finally extending its base close to the nasal aperture (fig. 592.). The tusk is formed by successive calcification of layers of the pulp in contact with the inner surface of the pulp cavity ; and, being subject to no habitual attrition from an opposed tooth, but being worn only by the occasional uses to which it is applied, it arrives at an extraordinary length, following the curve originally\nLoc. cit., p. 212.","page":923},{"file":"p0924.txt","language":"en","ocr_en":"924\nTEETH.\nimpressed upon it by the form of the socket, and gradually widening from the projecting apex to that part which was formed when the matrix and the socket had reached their full size.\n\u201c These incisive teeth of the elephant not only surpass other teeth in size, as belonging to a quadruped so enormous, but they are the largest of all teeth in proportion to the size of the body; representing in a natural state those monstrous incisors of the Rodents, which are the result of accidental suppression of the wearing force of the opposite teeth.\u201d\nThe tusks of the elephant, like those of the Mastodon, consist chiefly of that modification of dentine which is called \u201c ivory,\u201d and which shows, on transverse fractures or sections, striae proceeding in the arc of a circle from the centre to the circumference, in opposite directions, and forming by their decussations curvilinear lozenges. This character is peculiar to the Proboscidian Pachyderms.\nIn the Indian elephant the tusks are always short and straight in the female, and less deeply implanted than in the male : she thus retaining, as usual, more of the characters of the immature state. In the male they have been known to acquire a length of nine feet, with a basal diameter of eight inches, and to weigh one hundred and fifty pounds ; but these dimensions are rare in the Asiatic species.\nMr. Corse, speaking of the variety of Indian elephant, called \u201cDauntelah \u201d from its large tusks, which project almost horizontally with a slight curve upwards and outwards, says, \u201c The largest I have known in Bengal did not exceed seventy-two pounds avoirdupois ; at Tiperah they seldom exceed fifty pounds.\u201d There are varieties of the Dauntelah in which the large tusks of the male are nearly or quite straight ; and in a more marked breed called \u201c Mooknah,\u201d the tusks are much smaller, are straight, and point directly downwards. These ascertained varieties in an existing species ought to weigh with the observers of analogous varieties in the teeth of fossil Proboscidians, before they pronounce definitely on their value as characters of distinct species. More anomalous varieties occasionally present themselves in the Indian Elephant, as when one tusk is horizontal, the other vertical ; or when, from some distortion of the alveolus, a spiral direction is impressed upon the growth of the tusk, as in that specimen figured by Grew in the \u201cRarities of Gresham College,\u201d Tab. 4., and which is now in the Museum of the Royal College of Surgeons, London. The tusk of the elephant is slightly moveable in its socket, and readily receives a new direction of growth from habitual pressure ; this often causes distorted tusks in captive elephants, and Cuvier * relates the mode in which advantage was taken of the same impressibility, in order to rectify the growth of such tusks in an elephant kept at the Garden of Plants.\nThe tusks of the extinct Elephas primi-\n* Ossemens Fossiles, 4to. 1821, tom. i. p. 47.\ngenius, or Mammoth, have a bolder and more extensive curvature than those of the Elephas indiens : some have been found which describe a circle ; but, the curve being oblique, they thus clear the head, and point outwards, downwards, and backwards. The numerous fossil tusks of the Mammoth which have been discovered and recorded, may be ranged under two averages of size : the larger ones at nine feet and a half, the smaller at five feet and a half in length. I have elsewhere * assigned reasons for the probability of the latter belonging to the female Mammoth, which must accordingly have differed from the existing elephant of India, and more resembles that of Africa in the development of her tusks ; yet manifesting an intermediate character by their smaller size. Of the tusks which are referable to the male Mammoth, one from the newer tertiary deposits in Essex, measured nine feet ten inches along the outer curve, and two feet five inches in circumference at its thickest part ; another from Eschscholtz Bay was nine feet two inches in length, and two feet one and a half inches in circumference, and weighed one hundred and sixty pounds. A Mammoth\u2019s tusk has been dredged up off Dungeness which measured eleven feet in length. In several of the instances of Mammoth\u2019s tusks from British strata, the ivory has been so little altered as to be fit for the purposes of manufacture ; and the tusks of the Mammoth, which are still better preserved in the frozen drift of Siberia, have long been collected in great numbers as articles of commerce, f\nCuvier J states that the elephant of Africa, at least, in certain localities, has large tusks in both sexes, and that the female of this species, which lived seventeen years in the menagerie of Louis XIV., had larger tusks than those in any Indian elephant, male or female, of the same size which he had seen. The ivory of the tusks of the African elephant is most esteemed by the manufacturer for its density and whiteness.\nThe molar teeth of the elephant are remarkable for their great size, even in relation to the bulk of the animal, and for the extreme complexity of their structure. The crown, of which a great proportion is buried in the socket, and very little more than the grinding surface appears above the gum, is deeply divided into a number of transverse perpendicular plates (flg. 557), consisting each of a body of dentine (d), coated by a layer of enamel (c), and this again by the less dense bone-like\n* History of British Fossil Mammalia, 8vo. 1844, p. 244.\nf In the account of the Mammoth\u2019s hones and teeth of Siberia, published in the \u201c Philosophical Transactions \u201d for 1737 (No. 446), tusks are cited which weighed two hundred pounds each, and \u201c are used as ivory, to make combs, boxes, and such other things; being but little more brittle, and easily turning yellow by weather and heat.\u201d From that time to the present there has been no intermission in the supply of ivory, furnished by the tusks of the extinct elephants of a former world.\nX Loc, tit., p. 55.","page":924},{"file":"p0925.txt","language":"en","ocr_en":"TEETH.\n925\nsubstance (c) which fills the interspaces of the enamelled plates, and here more especially merits the name of \u201c cement,\u201d since it binds together the several divisions of the crown before they are fully formed and united by the confluence of their bases into a common body of dentine. As the calcification of each plate begins at the summit, they remain detached from each other and like so many separate teeth or denticules, until their base is completed, when it becomes blended with the bases of contiguous plates to form the common body of the crown of the complex tooth from which the roots are next developed.\nThe plates of the molar teeth of the Siberian Mammoth (Elcphas primigenins) are thinner in proportion to their breadth, and are generally a little expanded at the middle ; and they are more numerous in proportion to the size of the crown than in the existing species of Asiatic Elephant. In the African Elephant, on the other hand, the lamellar divisions of the crown are fewer and thicker, and they expand more uniformly from the margins to the centre, yielding a lozenge-form when cut or worn transversely, as in mastication.\nThe horizontal as well as vertical course of development of the elephant\u2019s grinder is well illustrated by the Mammoth\u2019s molar, the last of the lower jaw. The separate digital processes of the posterior plates are still distinct, and adhere only by the remaining cement ; a little in advance we see them united to form the transverse plate ; and, at the opposite extremity of the tooth, the common base of dentine is exposed by which the plates are finally blended into one individual complex grinder*; this never takes place simultaneously along the whole course of the tooth in the larger molars of the existing Indian elephant, or its extinct congener, the Mammoth. The African elephant, and some of the extinct Indian species, as the El. planifions, manifest their affinity to the Mastodon by the basal confluence of the hindmost plates before the foremost ones are worn out. The formation of each grinder begins with the summits of the anterior plate, and the rest are completed in succession ; the tooth is gradually advanced in position as its growth proceeds ; and, in the existing Indian elephant, the anterior plates are brought into use before the posterior ones are formed. When the complex molar cuts the gum the cement is first rubbed off the digital summits : then their enamel cap is worn away, and the\n* Some anatomists describe the divisions of the crown of the elephant\u2019s grinder as so many \u201c distinct teeth ; \u201d and Mr. Corse (loc. cit. p. 213.), who first propounded this view, calls each complex grinder \u201c a case of teeth,\u201d and states \u201c that these teeth are merely joined to each other by an intermediate softer substance, acting like a cement.\u201d But this description applies only to the imperfectly-formed tooth ; and the detached eminences of the crown of any complex tooth, at that stage of growth when they are held together only by the still uncalcified supporting matrix, might with equal justice be regarded as so many distinct teeth.\ncentral dentine comes into play with a prominent enamel ring ; the digital processes are next ground down to their common uniting base, and a transverse tract of dentine with its wavy border of enamel is exposed ; finally, the transverse plates themselves are abraded to their common base of dentine, and a smooth and polished tract of that substance is produced.* From this basis the roots of the molar are developed, and increase in length to keep the worn crown on the grinding level, until the reproductive force is exhausted. When the whole extent of a grinder has successively come into play, its last part is reduced to a long fang supporting a smooth and polished field of dentine, with, perhaps, a few remnants of the bottom of the enamel folds at its hinder part. When the complex molar has been thus worn down to a uniform surface it becomes useless as an instrument for grinding the coarse vegetable substances on which the elephant subsists ; it is attacked by the absorbent action, and the wasted portion of the molar is finally shed.\nThe grinding teeth of the elephant progressively increase in size, and in the number of lamellar divisions, from the first to the last ; and, as the rate of increase in both respects is nearly identical in both jaws, I shall describe them chiefly as they appear in the lower one.\nThe first molar, which cuts the gum in the course of the second week after birth, has a sub-compressed crown, nine lines in anteroposterior diameter, divided by three transverse clefts into four plates, the third being the broadest, and the tooth here measuring six lines across f ; the first and second plates have two mammilloid summits ; the third and fourth have three or four such; there is a single and sometimes a double mammilloid summit at the fore and back part of the crown ; the base slightly contracts, and forms a neck as long as the enamelled crown, but of less breadth, and this divides into two, an anterior and posterior, long, sub-cylindrical, diverging, but mutually incurved fangs ; the total length of this tooth is one inch and a half. The corresponding upper molar, which Mr. Corse describes as cutting the gum a little earlier than the lower one, has the anterior single digital process or mammilla, and the posterior talon developed into a fifth plate, smaller than the fourth, with which its middle part is confluent ; the neck of this tooth is shorter, and the two fangs are shorter, larger, and more compressed than those of the lower first molar. This tooth is the homologue of the probably deciduous molar (d. 2) in other\n* In the fossil specimen figured in plate 147, of my \u201c Odontography,\u201d the left molar l, exhibits all the above-described gradations of use ; but the right molar, r, through some accident to the opposing tooth in the lower jaw, has not been so worn, hut projects beyond the level of the left molar, with the mammillated margins of the plates entire.\nf These are also the dimensions of the first lower molar figured by Mr. Corse, loc. cit. pi. vi.fig. 1, d, and fig. 3 ; but I have seen the first lower molar of smaller dimensions.","page":925},{"file":"p0926.txt","language":"en","ocr_en":"926\nTEETH.\nUngulates ; it is not a mere miniature oF the great molars of the mature animal, hut re-rains, agreeably with the period of life at which it is developed, a character much more nearly approaching that of the ordinary Pa-chydermal molar, manifesting the adherence to the more general type by the minor complexity of the crown, and by the form and relative size of the fangs. In the transverse divisions of the crown we perceive the affinity to the Tapiroid type, the different links connecting which with the typical elephants are supplied by the extinct Lophiodons, Dino-theriums, and Mastodons. The sub-division of the summits of the primary plates recalls the character of the molars, especially the smaller ones, of the Phacoch\u00e8re in the Hog-tribe. As the elephant advances in age the molars rapidly acquire their more special and complex character.\nThe first molars are completely in place, and in full use at three months, and are shed when the elephant is about two years old.\nThe sudden increase and rapid development of the second molar may account for the non-existence of any vertical successor to the former tooth, or \u201cpremolar,\u201d in the elephant. The eight or nine plates of the crown are formed in the closed alveolus, behind the first molar by the time this cuts the gum, and they are united with the body of the tooth, and most of them in use, when the first molar is shed.\nThe average length of the second molar is two inches and a half; ranging from two inches to two inches and nine lines. The greatest breadth, which is behind the middle of the tooth, is from one inch to one inch three lines. There are two roots : the cavity of the small anterior one expands in the crown, and is continued into that of the three anterior plates. The thicker root supports the rest of the tooth. The second molar is worn out and shed before the beginning of the sixth year.\nThe third molar has the crown divided into from eleven to thirteen plates ; it averages four inches in length, and two inches in breadth, and has a small anterior, and a very large posterior root ; it begins to appear above the gum about the end of the second year, is in its most complete state and extensive use during the fifth year, and is worn out and shed in the ninth year. The last remnant of the third molar is shown at m. 3, fig. 592.\nIt is probable that the three teeth above described are homologous with the deciduous molars, d. 2, d.3, and dA, in the Hyrax and horse.\nThe fourth molar presents a marked superiority of size over the third, and a somewhat different form : the anterior angle is more obliquely abraded, giving a pentagonal figure to the tooth in the upper jaw {fig. 592. m. 4). The number of plates in the crown of this tooth is fifteen or sixteen : its length between seven and eight inches ; its breadth three inches. It has an anterior simple and slender root supporting the three first plates ; a\nsecond of larger size and bifid, supporting the four next plates ; and a large contracting base for the remainder. The fore-part of the grinding surface of this tooth begins to protrude through the gum at the sixth year : the tooth is worn away, and its last remnant shed, about the twentieth or twenty-fifth year. It may be regarded as the homologue of the first true molar of ordinary Pachyderms (m. 1).\nThe fifth molar, with a crown of from seventeen to twenty plates, measures between nine and ten inches in length, and about three inches and a half in breadth. The second root is more distinctly separated from the first simple root than from the large mass behind. It begins to appear above the gum about the twentieth year : its duration has not been ascertained by observation ; but it probably is not shed before the sixtieth year.\nThe sixth molar appears to be the last, and has from twenty-two to twenty-seven plates ; -its length, or antero-posterior extent, following the curvature, is from twelve to fifteen inches : the breadth of the grinding surface rarely exceeds three inches and a half.\nThe reproductive power of the matrix in some cases surpasses that of the formative development of the cavity for lodging the tooth, and the last lamellae are obliged to be folded from behind forwards upon the side of the tooth. Fig. 99, p. 233. of my \u201c History of British Fossil Mammals,\u201d shows this condition in the last lower molar of the Mammoth.\nOne may reasonably conjecture that the sixth molar of the Indian elephant, if it make its appearance about the fiftieth year, would, from its superior depth and length, continue to do the work of mastication until the ponderous Pachyderm had passed the century of its existence.\nMr. Corse has figured the sixth molar, (which he calls the seventh or eighth,) with twenty-three plates, in tab. x. of his Memoir, and a small cavity, c, is marked as an incipient alveolus for a succeeding grinder. Had it actually been such, it might have been expected to contain some calcified portions of the anterior plates of such succeeding grinder.\nThe molar teeth, in all the species of elephant, succeed each other from behind forwards, moving, not in a right line, but in the arc of a circle, shown by the curved line in fig. 592. The position of the growing tooth in the closed alveolus (m. 5) is almost at right angles with that in use, the grinding surface being at first directed backwards in the upper jaw, and forwards in the lower jaw', and brought, by the revolving course, into a horizontal line in both jaws, so that they oppose each other, when developed for use. The imaginary pivot on which the grinders revolve is next their root in the upper jaw, and is next the grinding surface in the lower jaw ; in both, towards the frontal surface of the skull. Viewing both upper and lower molars as one complex whole, subject to the same revolving movement, the section dividing such whole into upper and lower portion runs","page":926},{"file":"p0927.txt","language":"en","ocr_en":"TEETH.\n927\nparallel to the curve described by that movement, the upper being the central portion, or that nearest the pivot, the lower, the peripheral portion : the grinding surface of the upper molars is consequently convex from behind forwards, and that of the lower molars concave : the upper molars are always broader than the lower ones. The bony plate forming the sockets of the growing teeth is more than usually distinct from the body of the maxillary, and participates in this revolving course, advancing forwards with the teeth. The partition between the tooth in use and its successor is perforated near the middle ; and, in its progress forwards, that part next the grinding surface is first absorbed ; the rest disappearing with the absorption of the roots of the preceding grinder.\nThere are few examples of organs that manifest a more striking adaptation of a highly complex and beautiful structure to the exigencies of the animal endowed with it, than the grinding teeth of the elephant. We perceive, for example, that the jaw is not encumbered with the whole w'eight of the massive tooth at once, but that it is formed by degrees as it is required ; the division of the crown into a number of successive plates, and the subdivision of these into cylindrical processes, presenting the conditions most favourable to progressive formation. But a more important advantage is gained by this subdivision of the tooth ; each part is formed like a perfect simple tooth, having a body of dentine, a coat of enamel, and an outer investment of cement : a single digital process may be compared to the simple canine of a Carnivore ; a transverse row of these, therefore, when the work of mastication has commenced, presents, by virtue of the different densities of their constituent substances, a series of cylindrical ridges of enamel, with as many depressions of dentine, and deeper external valleys of cement : the more advanced and more abraded part of the crown is traversed by the transverse ridges of the enamel inclosing the depressed surface of the dentine, and separated by the deeper channels of the cement : the fore-part of the tooth exhibits its least efficient condition for mastication ; the inequalities of the grinding surface being reduced in proportion as the enamel and cement which invested the dentinal plates have been worn aw\u2019ay. This part of the tooth is, however, still fitted for the first coarse crushing of the branches of a tree : the transverse enamel ridges of the succeeding part of the tooth divide it into smaller fragments, and the posterior islands and tubercles of enamel pound it to the pulp fit for deglutition. The structure and progressive development of the tooth not only give to the elephant\u2019s grinder the advantage of the uneven surface which adapts the millstone for its office, but, at the same time, secure the constant presence of the most efficient arrangement for the finer comminution of the food, at the part of the mouth which is nearest the fauces.\nWith regard to the microscopic structure of the peculiar modification of dentine called \u201c ivory,\u201d this is characterised partly by the minute size of the tubes, which, at their origin from the pulp cavity, do not exceed Tri__th of an inch in diameter, in their close arrangement at intervals scarcely exceeding the breadth of a single tube, and, above all, on their strong and almost angular gyrations, which are much greater than the secondary curvatures of the tubes of ordinary dentine.\nThe dentinal tubes of ivory, as they radiate from the pulp-cavity, incline obliquely towards the pointed end of the tusk, and describe two slight primary curves, the first convex towards that end, the second and shorter one concave ; these curves in narrow sections from near the open base of the tusk are almost obscured by the strong angular parallel secondary gyrations. The tubes divide dicho-tomously, at acute angles, and gradually decrease in size as they approach the periphery of the tusk.\nThe characteristic appearance of decussating curved striae, with oblique rhomboidal spaces, so conspicuous on transverse sections or fractures of ivory, is due to the refraction of light caused by the parallel secondary gyrations of the tubes above described. The strong contour lines observed in longitudinal sections of ivory, parallel with the cone of the pulp-cavity, and which are circular and concentric when viewed in transverse slices of the tusk, are commonly caused by strata of minute opaque cellules, which are unusually numerous in the interspaces of the tubes throughout the substance of the ivory, and by their very great abundance and larger size in the peripheral layers of cement. The close-set lateral branches of the calcigerous tubes unite with the tubuli of the cells. The decomposition of the fossil tusks into superimposed conical layers takes place along the strata of the opaque cellules, and directly across the course of the calcigerous gyrating tubes.\nThe radiated cells of the true cement are larger and more uniform in size and shape ; many of them approach nearer the circular figure than in ordinary teeth ; the long axis of the more elliptical ones is parallel with the plane of the stratum of cement ; their average diameter is ^.^th of an inch, and the'r interspaces sometimes do not exceed that dimension. The cemental tubuli appear from their course, and sometimes from the overlapping of the substances in the sections examined, to be directly continued from the tubuli of the ivory ; but Retzius expressly denies the continuation, and states that the cemental tubes at both the outer and the inner surface of the cement have terminations of less diameter than their middle part. This is exact with respect to the major part of the cement. In that near the base of the tusk I have seen a few vascular canals. The contour lines of the cement are usually wavy, and not parallel with the line of the outer surface of the ivory.\nIn the tusks of the Mastodon giganteus the","page":927},{"file":"p0928.txt","language":"en","ocr_en":"928\nTEETH.\nouter layer of cement is relatively thicker than in the tusks of the Mammoth or in those of the Indian elephant. The general character of the microscopic structure of the ivory of the Mastodon\u2019s tusk is the same as that of the elephant. The peripheral extremities of the dentinal tubes are, in some parts of the tusk, straighter than in the rest of their course ; the straighter extremities were those which were first formed in the calcification of the peripheral part of the pulp, and this first-formed ivory is accordingly, in such parts, more like the ordinary dentine, and is analogous to the thin peripheral cap of such substance in the teeth of the Sloth and of some fishes.\nThe pulp soon, however, becomes subject to that modification of the calcifying processes by which the more tortuous disposition of the tubuli and the more frequent interposition of opaque cellules are produced ; modifications which, in establishing the characters of ivory, present a step in the transition from true dentine to osteo-dentine.\nBy the minuteness and close arrangement of the tubes, and especially by their strongly undulating secondary curves, a tougher and more elastic tissue is produced than results from their disposition in ordinary dentine ; and the modification which distinguishes \u201c ivory \u201d is doubtless essential to the due degree of coherence of so large a mass as the elephant\u2019s tusk, projecting so far from the supporting socket, and to be frequently applied in dealing hard blows and thrusts.\nThe central part of the tusk, especially near the base of such as have reached their lull size, is occupied by a slender cylindrical tract of modified ivory, perforated by a few vascular canals, which is continued to the apex of the tusk. It is not uncommon to find processes of osteo-dentine or imperfect bone-like ivory, projecting in a stalactitic form* into the interior of the pulp-cavity, apparently the consequence of partial inflammation or malformation of the vascular pulp. The musket-balls and other foreign bodies which are occasionally found in ivory, are immediately surrounded by osteo-dentine in greater or less quantity. It has long ceased to be a matter of wonder how such bodies should become completely imbedded in the substance of the tusk, sometimes without any visible aperture, or how a leaden bullet may have become lodged in the solid centre of a very large tusk without having been flattened. Such a ball, aimed at the head of an elephant, may penetrate the thin bony socket and the thinner ivory parietes of the wide conical pulp-cavity occupying the inserted base of the tusk ; if the projectile force was there spent, the ball would gravitate to the opposite and lower side of the pulp-cavity, as indicated in Jig. 592.f The presence of the foreign body\n* Haller seems to have been the first to notice these irregular internal deposits in the pulp-cavity of the elephant\u2019s tusk. Elementa Physiologi\u00e6, tom. viii. p. 519.\t*\nf Camper, \u201c Description Anatomique d un Ele-\nexciting inflammation of the pulp, an irregular course of calcification ensues, which results in the disposition around the ball of a certain thickness of osteo-dentine. The pulp then resuming its healthy state and functions, coats the inner surface of the osteo-dentine inclosing the ball, together with the rest of the conical cavity into which that mass projects, with layers of normal ivory.*\nThe portion of the cement-forming capsule surrounding the base of the tusk, and the part of the pulp, which were perforated by the ball in its passage, are soon replaced by the active reparative power of these highly vascular bodies. The hole formed by the ball in the base of the tusk is then more or less completely filled up by a thick coat of cement from without and of osteo-dentine from within. Traces of such a cicatrix closing the entrance have been more than once noticed : and Blumenbach deduced, therefrom, a property in the elephant\u2019s tusk to pour out bony matter in order to heal such wounds. The reparation is however effected by the calcification of the reproduced parts of the capsule and pulp.\nBy the continued progress of growth, the ball so inclosed is carried forwards, in the course indicated by the arrow iny\u00eeg. 592., to the middle of the solidified exserted part of the tusk, as in the example in Blumenbach\u2019s collection which he considered so curious. Should the ball have penetrated the base of the tusk of a young elephant, it may be carried forwards by the uninterrupted growth of the tusk until that base has become the apex, and be finally exposed and discharged by the continual abrasion to which the apex of the tusk is subjected. Yet none of these phenomena prove the absolute non-vascularity of the tusk, but only the low degree of its vascularity. Blood circulates, slowly no doubt, through the minute vascular canals which are continued through the centre of the ivory to the very apex of the tusk : and it is from this source that the fine tubular structure of the ivory obtains the plasmatic colourless fluid by which its low vitality is maintained.\nDevelopment.-r-The matrix of the tusk consists of a large conical pulp, which is renewed quicker than it is converted, and thus is not only preserved, but grows, up to a certain period of the animal\u2019s life : it is lodged in the cavity at the base of the tusk ; this base is surrounded by the remains of the capsule, a soft vascular membrane of moderate thickness, which is confluent with the border of the base of the pulp, where it receives its principal vessels.\nphant Male,\u201d fol. p. 54. Cuvier, Annales du Museum, tom. viii. (1806) p. 115.\n* Cuvier, \u201cAnnales du Museum,\u201d tom. viii. p. 115, 1806, \u201c Sur les d\u00e9fenses des \u00e9l\u00e9phans, la structure, l\u2019accroissement, les caract\u00e8res distinctifs de l\u2019ivoire, et sur les maladies,\u201d first clearly stated that the ball or foreign body in the tusk of the elephant was immediately surrounded by a substance different from the regular ivory. The great anatomist observes, \u201c Toute la portion d\u2019ivoire en dehors de la balle est semblable au reste ; il n\u2019y a que ce qui l\u2019entoure imm\u00e9diatement qui soit irr\u00e9gulier.\u201d","page":928},{"file":"p0929.txt","language":"en","ocr_en":"TEETH.\nI had the tusk and pulp of the great elephant at the Zoological Gardens longitudinally divided, soon after the death of that animal in the summer of 1847. Although the pulp could be easily detached from the inner surface of the pulp-cavity, it was not without a certain resistance, and when the edges of the coadapted pulp and tooth were examined by a strong lens, the filamentary processes from the outer surface of the pulp could be seen stretching, as they were withdrawn from the dentinal tubes, before they broke. They are so minute that, to the naked eye, the detached surface of the. pulp seems to be entire, and Cuvier was thus deceived in concluding that there was no organic connection between the pulp and the ivory.* As the learned professor who has contributed the article \u201c Pachyder-mata \u201d adopts Cuvier\u2019s description of the formation of the teeth of the elephant by deposition and transudation of the tissues from free surfaces of the formative organs, I have the more valued the rare opportunity of testing and confirming, by examination of the recent animal, the account of the processes of conversion of those organs into the dental tissues, which I gave in my \u201c Odontography.\u201d\nEach molar of the elephant is formed in the interior of a membranous sac\u2014the capsule, the form of which partakes of that of the future tooth, being cubical in the first molar, oblong in the last, and rhomboidal in most of the intermediate teeth ; but always decreasing in vertical extent towards its posterior end, and closed at all points, save where it is penetrated by vessels and nerves. It is lodged in an osseous cavity of the same form as itself, and usually in part suspended freely in the maxillary bone ; the bony case being destined to form part of the socket of the tooth. The exterior of the membranous capsule is simple and vascular, as shown at m. 5, fig. 592. ; its internal surface gives attachment to numerous folds or processes, as in most other Ungulate animals.\nThe dentinal pulp rises from the bottom of the capsule, or that part which lines the deepest part of the alveolus, in the form of transverse parallel [dates extending towards that part of the capsule ready to escape from the socket. These plates adhere only to the bottom of the capsule ; their opposite extremity is free from all adhesion. This summit is thinner than the base ; it might be termed the edge of the plate: but it is notched, or divided into many digital processes. The tissue of these digitated plates is identical with that of the dentinal pulp of simple Mammalian teeth ; it becomes also highly vascular at the parts where the formation of the dentine is in active progress.\nProcesses of the capsule descend from its summit into the interspaces of the dentinal pulp-plates, and consequently resemble them in form ; but they adhere not only by their\n* Annales du Museum, tom. viii. (1806), p. 94. The account is repeated verbatim in the posthumous edition of the \u201c Ossemens Fossiles,\u201d 1836.\nVOL. IV.\n929\nbase to the surface of the capsule next the mouth, but also by their lateral margins to the sides of the capsule, and thus resemble partition-walls, confining each plate of the dentinal pulp to its proper chamber ; the margin of the partition opposite its attached base is free in the interspace of the origins of the dentinal pulp plates. The enamel organ, which Cuvier appears to have recognised under the name of the internal layer of the capsule, is distinguishable by its light blue sub-transparent colour and usual microscopic texture, adhering to the free surface of the partitions formed by the true inner layer of the capsule. Although the enamel-pulp be in close contact with the dentinal pulp prior to the commencement of the formation of the tooth, one may readily conceive a vacuity between them, which is continued uninterruptedly, in many foldings, between all the gelatinous plates of the dentinal pulp, and the partitions formed by the combined enamel-pulp and the folds of the capsule. According to the excretion-view, this delicate apparatus must have been immediately subjected to the violence of being compressed in the unyielding bony box, by the deposition of the dense matters of the tooth in the hypothetical vacuity between the enamel and dentinal pulps ; a process of absorption must have been conceived to be set on foot immediately that the altered condition of the gelatinous secreting organs took place ; and, according to Cuvier\u2019s hypothesis, the secreting function must be supposed to have proceeded, without any irregularity or interruption, while the process of absorption was superinduced in the same part to relieve it from the effects of pressure produced by its own secretion.\nThe formation of the dentine commences immediately beneath the membrana propria of the pulp : a part which Cuvier distinctly recognised, and which he accurately traced as preserving its relative situation between the dentine and enamel throughout the whole formation of the dentine, and discernible in the completed tooth \u201c as a very fine greyish line, which separates the enamel from the internal substance \u201d or dentine.\nThe calcification and conversion of the cells of the dentinal pulp commence as usual at the peripheral parts of the lamelliform processes furthest from the attached base. It may readily be conceived, therefore, that, at the commencement, there is formed a little cap' upon each of the processes into which the edges of the pulp-plates are divided. As the centripetal calcification proceeds the caps are converted into horn-shaped cones ; when it has reached the bottom of the notches of the edge of the pulp-plate all the cones become united together into a single transverse plate ; and, the process of conversion having reached the base of the pulp-plate, these plates coalesce to form a common base to the crown of the tooth, which would then present the same eminences and notches that characterised the gelatinous pulp, if, during the period of conversion, other substances had\n3 o","page":929},{"file":"p0930.txt","language":"en","ocr_en":"930\nTEETH.\nnot been formed upon the surface and in the interspaces of the pulp-plates.\nCoincident, however, with the formation of the dentine, is the deposition of the hardening salts of the enamel in the extremely slender prismatic cells, which are for the most part vertical to the plane of the inner surface of the folds of the capsule to which they are attached ; these cells or moulds give a subtransparent bluish tint to the enamel pulp. The true inner part of the capsule forms those thick transverse folds or partitions which support the enamel organ, and with it fill the interspaces of the dentinal pulps. With regard to the formation of the cement, Cuvier, after citing the opinion of Tenon\u2014that it was the result of ossification of the internal layer of the capsule, and that of Blake \u2014 that it was a deposition from the opposite surface of the capsule to that which had deposited the enamel, states his own conviction to be that the cement is produced by the same layer and by the same surface as that which has produced the enamel. The proof alleged is, that so long as any space remains between the cement and the external capsule, that space is found to contain a soft internal layer of the capsule with a free surface next the cement. The phenomena could not, in fact, be otherwise explained according to the \u201c excretion theory \u201d of dental development. To the obvious objection that the same part is made, in this explanation, to secrete two different products, Cuvier replies, that it undergoes a change of tissue : \u201c Whilst it yielded enamel only it was thin and transparent ; to give cement it becomes thick, spongy, and of a reddish colour.\u201d* The external characters of the enamel organ and cement-forming capsule are correctly defined ; only, the one, instead of being converted into the other, is in fact changed into its supposed transudation : the enamel fibres being formed, and properly disposed in the direction in which their chief strength is to lie, by the assimilative properties of the pre-arranged elongated prismatic non-nucleated cells, which take from the surrounding plasma the required salts and compact them in their interior.\nWhilst this process is on foot, and before the enamel fibres are firm in their position, the capsule begins to undergo that change which results in the formation of the thick cement ; the calcifying process commences from several points, and proceeds centrifu-gally, radiating therefrom, and differing from the ossification of bone chiefly in the number of these centres, which, though close to the new-formed enamel, are in the substance of the inner vascular surface of the capsular folds. The cells arrange themselves in concentric layers around the vessels, and act\n* \u201c Seulement elle change de tissue : tant qu\u2019elle ne donnait que de l\u2019email, elle \u00e9tait mince et transparente ; pour donner du cortical elle devient \u00e9paisse, spongieuse, opaque et rouge\u00e2tre.\u201d \u2014 Annales du Mus\u00e9um, tom. viii. p. 99 ; Ossemens Fossiles, ed. 1834, 8vo. tom. i p. 514. Art. Pachydermata, p. 8G9.\nlike those of the enamel pulp in receiving into their interior the bone-salts in a clear and compact state; during this process they become confluent with each other, their primitive distinctness being indicated only by their persistent granular nuclei, which now form the radiated Purkinjian corpuscles. The interspaces of the concentric series of confluent cells become, filled with the calcareous salts in a rather more opaque state, and the conversion of the capsule into cement goes on, according to the processes more particularly described in the Introduction to my \u201c Odontography,\u201d until a continuous stratum is formed in close connection with the layer of enamel.\nThe uncalcified part of the capsule, always much softer than cartilage, is very readily detached from the calcified part, and to the naked eye the separated surface seems entire, and might readily pass, as with Cuvier, for a secreting surface. But the fine vascular processes which have been torn from the medullary canals of the calcified part are conspicuous, and resemble villi, when the detached surface is examined, even with a moderate magnifying power, under water.\nCalcification extending from the numerous centres, the different portions coalesce and progressively add to the thickness of the cement until all the interspaces of the coronal plates and the whole exterior of the crown is covered with the bone-like substance. The enamel-pulp ceases to be developed at the base of the crown, but the capsule continues to be formed 'pari passu with the partial formation of the pulp, as this continues, progressively contracting, from the base of the crown, to form by its calcification the roots. The calcification of the capsule going on at the same time, a layer of cement is formed in immediate connection with the dentine. The circumscribed spaces at the bottom of the socket to which the capsule and dentinal pulp adhere, where they receive their vessels and nerves, and which are the seat of the progressive formation of these respective moulds of the two dental tissues, become gradually contracted, and subdivided by the further localisation of the reproductive forces to particular spots, whence the subdivision of the base into roots. The surrounding bone undergoes corresponding modifications, growing and filling up the interspaces left by the dividing and contracting points of attachment of the residuary matrix. All is subordinated to one harmonious law of growth by vascular action and cell-formation, and of molecular decrement modifying form by absorption. Mechanical squeezing or drawing out have no share in these changes of the pulp or capsule ; pressure at most exercises only a gentle stimulus to the vital processes. Cuvier believed that there were places where the dentinal pulp and the capsule were separate from each other. I have never found such except where the enamel-pulp was interposed between them in the crown of the tooth, or where both pulp and capsule adhered to the periosteum of the socket, below the crown.","page":930},{"file":"p0931.txt","language":"en","ocr_en":"TEETH.\n931\nCuvier affirms that the number of fangs of an elephant\u2019s molar depends upon the number of points at which the base of the gelatinous (dentinal) pulp is attached to the bottom of the capsule ; and that the interspaces of these attachments constitute the under part of the crown or body of the tooth, the attachments themselves forming the first beginnings of the fangs. True to his hypothesis of the formation of the dental tissues by excretion, he says * that the elongation of the fangs is produced by two circumstances : first, the progressive elongation of the layers of osseous substance (dentine) which force the tooth to rise and emerge from its socket; secondly, the thickening of the body of the tooth by the addition of successive layers to its inner surface, which, filling up the interior cavity, leaves scarcely room for the gelatinous pulp, and forces it down into the interior of the roots.\nThis pulling up of the fang on the one hand, and squeezing down the pulp on the other, are forces too gross and mechanical to be admitted in actual physiology to explain the growth of the root of a tooth or of any other organised product ; such modes of explanation were, however, inevitable in adopting the excretion theory of dental development.\nWith regard to the homologies of the complex molars of the Proboscidian quadrupeds, a species of insight which may come to be deemed, in the course of anatomical science, as of equal import to the knowledge of the formative processes of parts, I must admit that the mere fact of the marked and disproportionate increase of size of the first of the three last molars over its predecessor\u2014the last of the first three that are developed \u2014 may appear but a feeble support to the analogical evidence on which, chiefly, I have classed the three last developed molars of the elephant, in a category distinct from that of their smaller predecessors. But the value of such indication and analogy will begin to be apparent when we examine the condition of dental development in the primeval forms of Proboscidians. I have already shown that the typical character of the Diphyodont dentition was more closely and generally adhered to in the genera that existed during the oldest tertiary periods in geology than in their actual successors : it became of course highly interesting to inquire whether the miocene Mastodons, the earliest of the great Proboscidian quadrupeds of which we have any cognizance, manifested any analogous closer adhesion to type than their elephantine successors, and whether they would afford any actual proof of the true deciduous nature of the first,\n* \u201c Ces racines et les p\u00e9dicules qui leur servent de noyaux s\u2019alongent ensuite par deux raisons : d\u2019abord les progr\u00e8s des lames de substance osseuse qui, s\u2019alon-geant toujours, forcent la dent \u00e0 s\u2019\u00e9lever et \u00e0 sortir de l\u2019alv\u00e9ole ; ensuite l\u2019\u00e9paississement du corps de la dent par la formation des couches successives qui, en remplissant le vide int\u00e9rieur, n\u2019y laissent presque plus de place pour le noyau g\u00e9latineux, et le refoulent vers l\u2019int\u00e9rieur des tubes des racines.\u201d Annales du Mus\u00e9um, viii. 1807,p. 108; Ossem. Fossiles, 1834, p. 527.\nsecond, or third molars, by the development of a vertical successor or premolar. Cuvier first ascertained the fact, though without appreciating its full significance, in a specimen of the upper jaw of the Mastodon angustidens from Dax, in which the second six-lobed deciduous molar was displaced by a four-lobed or quadricuspid premolar developed above it and succeeding it vertically.* The same important fact was subsequently confirmed by Dr. Kaup in observations of the Mastodon longirostns of the miocene tertiary deposits of Eppelsheim.-}*\nThis satisfactorily proves the true deciduous character of the first and second molars ; and that the third molar in order of appearance f, is also one (the last) of the deciduous series, is indicated by the contrasted superiority of size of the ante-penultimate tooth, which I regard as the first of the true molar series.\nThe great extent and activity of the processes of dental development required for the preparation of the large and complex true molar teeth would seem to exhaust the power, which, in ordinary Pachyderms, is expended in developing the vertical successors of the deciduous teeth. In the primeval Mastodons above cited, this normal exercise of the reproductive force was not, however, wholly exhausted, and one premolar, of more simple form than its deciduous predecessor, was developed on each side of both jaws. But even this trace of adherence to the archetypal dentition is lost in the more modified Proboscidians of the present day.\nAnother and very interesting mark of adhesion to the archetype is shown by the development of two incisors in the lower jaw in the young of some of the Mastodons, by the retention and development of one of these inferior tusks in the male of the Mastodon giganteus of North America, and by the retention of both in the European Mastodon longi-rostris. No trace of these inferior homotypes of the great premaxillary tusks have been detected in the foetus or young of the existing elephants.\nIn the gigantic Dinoth\u00e9rium the upper incisors were suppressed, and the two lower incisors wrere developed into huge tusks, which curved down from the symphysis of the massive under jaw. Most of the grinders had two transverse ridges on the crown, as in the Tapir ; two deciduous molars, if not three, were succeeded vertically by two premolars, the second of which (jo. 4 of the typical series) closely resembles the true molars, as in other Perissodactyles.\nThe typical dentition is departed from in the existing Hippopotamus by the early loss of jo. 1, and the reduction of the incisors to\n\t\u2014\u00e4\n2-\t^2\nin both jaws : in the extinct Hippopota-\nmus of India jo. 1 was longer retained, and the\n* Ossemens Fossiles, 4to. ; Divers Mastodontes, pi. iii. fig. 2.\nf Ossemens Fossiles de Darmstadt, 1835, pi. 1. t Odontography, pi. 144, fig. 11, d. 3\n3 o 2","page":931},{"file":"p0932.txt","language":"en","ocr_en":"932\nTEETH.\nincisors were in normal number\n3\u20143\n3\u20143\n; whence\nthe term Hexaprotodon proposed for this interesting restoration by its discoverers, Cautley and Falconer.\nI have before remarked that the even-toed or artiodaetyle Ungulata superadd the characters of simplified form and diminished size to the more important and constant one of vertical succession in their premolars. These teeth in the Ruminants, e. g. {fig. 580., VIE, Moschus,p. 2, 3,4), represent only the moiety of the true molars, or one of the twosemi-cylin-drical lobes of which those teeth consist, with at most a rudiment of the second lobe, as Cuvier very accurately describes*, and F. Cuvier figures in pi. 94. of his useful work, \u201c Dents des Mammif\u00e8res.\u201d An analogous morphological character of the premolars will be found to distinguish them in the dentition of the genus Sus (figured in my \u201c Odontography,\u201d pi. MO.,figs. 1 and 2), in the Hippopotamus (ib. pi. 143.), andin the Phacochcerus (ib. pi. 141.), where the premolar series is greatly reduced in number : yet this instance of a natural affinity manifested in so many other parts of the organisation of the artiodaetyle genera has been overlooked in F. Cuvier\u2019s work above cited, although it is expressly designed to show how such zoological relations are illustrated by the teeth. Confiding in the accuracy of the Baron Cuvier\u2019s division of the hoofed quadrupeds into \u201c Pachyderms \u201d and \u201c Ruminants,\u201d M. F. Cuvier separates the non ruminant Artiodactyles from the ruminant genera of the same natural division by interposing the Tapir, Hyrax, Rhinoceros and Elephant ; whilst the horse, which, in the size and complexity of its premolars, as well as in many other characters, agrees closely with the other perissodactyle Pachyderms, is placed in close juxtaposition with the Ruminants.')'\nMost of the deciduous molars of the Ruminants resemble in form the true molars; the last, e.g. {fig. 593., d. 4), has three lobes in the owerjaw J likethelasttruemo!ar(?\u00bb.3.). They\nFig. 593.\nPermanent and deciduous teeth, Sheep (Ovis). (Lower jaw.)\nare three in number on each side, and, being succeeded by as many premolars, the ordinary\npermanent molar formula is p. -\u2014-, m. -\u2014_ ;\no\u20143\t3\u20143\n* Ossemens Fossiles, 4to, tom. iv. p. 6. f See my \u201c Remarks on the Classification of the Hoofed Quadrupeds \u201d in \u201cQuarterly Journal of the Geological Society,\u201d May, 1848.\n$ When, therefore, the third grinder of the lower jaw of any new or rare Ruminant shows three lobes, the crowns of the premolars should be sought for in the substance of the jaw below these, and above\nbut there is a rudiment of d. 1 in the embryo fallow-deer, and in one of the most ancient of the extinct Ruminants (Dorcatherium, Kaup) the normal number of premolars was fully developed.\nSufficient, it is hoped, has been adduced to prove that the molar series of the Diphyo-donts is naturally divisible into only two groups, premolars and molars ; that the ty-4__________________________4 3___3\npical number of these is -\u2014- -\u2014- ; and that\nT--T O---O\neach individual tooth may be determined and symbolised throughout the series, as is shown in the instances under cut 580. If anything were wanting to prove the artificial character of a three-fold division of these teeth, and the futility of any other classification than that founded upon development, it would be afforded by the attempt to determine the homologous teeth which is exemplified by the dotted line which traverses the series, and which crosses the teeth distinguished by the name \u201cprincipales\u201d in the great \u201c Ost\u00e9o-graphie and Odontographie \u201d now in course of publication by Prof, de Blainville.\nThis author abandons the classification of the molar series adopted by the Cuviers, without assigning his objections to it ; and proposes another, in which he divides the series into \u201c avant-molaires, principales; and arri\u00e8re-molaires;\u201d he exemplifies this division by the human dentition, in which the five grinders on each side of both jaws are formalised as \u201c deux avant-molaires, une principale, et deux arri\u00e8re-molaires.\u201d*\nWith regard to the characters of these kinds of teeth, the avant-molaires are \u201csimple or complex,\u201d the principale is \u201c trenchant,\u201d and the arri\u00e8re-molaires are \u201c tuberculous.\u201d f But as shape is not a constant character, especially in the \u201c principale,\u201d the author proposes another from its position, describing it as \u201c being implanted below the root of the zygomatic process of the maxillary bone \u201d in the upper jaw ; and stating that the tooth which opposes it below, and is in advance of it, or crosses in front of it, is the lower \u201c principale.\u201d\nIn defining the dentition of the genus Felts f, M. de Blainville accordingly assigns 1 \u201cavant-molaire,\u201d 1 \u201c principale,\u201d and 2 \u201c arri\u00e8re-molaires \u201d in the upper jaw ; and 1 \u201c avant-molaire,\u201d 1 \u201c principale,\u201d and 1 \u201c arri\u00e8re-molaire \u201d in the lower jaw. In another part of the same work \u00a7, he. however, proposes another formula, viz., 2 \u201c avant-molaires,\u201d 1 \u201c principale,\u201d and 1 \u201c arri\u00e8re-molaire \u201d above ; ] \u201c avant-molaire,\u201d 1 \u201c principale,\u201d and 1 \u201c arri\u00e8re-molaire \u201d below; but, taking either of these determinations, or the dental formul\u00e6 which he assigns to other carnivorous genera, and comparing them with his formula of the\ntheir opponents in the upper jaw; and thus the true characters of the permanent dentition may he ascertained.\n* Osteographie, tom. i. p. 43. t Ib. p. 43.\n\u00ee Osteographie des Carnivores, p. 69.\n\u00a7 Osteographie des F\u00e9lis, p. 55.","page":932},{"file":"p0933.txt","language":"en","ocr_en":"I\nTEETH.\nmolar series in the Quadrumana and Man, we find that a tooth which displaces and succeeds a milk-tooth in one species is made the homologue of a tooth, which, in Man and Quadrumana, rises above the gum without displacing any predecessor; in other words, the \u201c principale \u201d is a premolar in certain genera, and a true molar in other genera. I may refer to my Paper on the Classification of the Molar Teeth in the \u201c Annales des Sciences,\u201d* and to the concluding pages of the chapter on the teeth of the Carnivora in my \u201c Odontography \u201d (p. 514), in proof that a \u201c molaire principale \u201d does not exist in nature ; that the characters by which it is defined by M. de Blainville are artificial ; and that they fail in their application to determine the teeth in the series of placental Mammalia with deciduous and permanent teeth.\nIn the series of figures, fig. 580., the continuous line traverses the tooth or its homologue, in Man and the Ruminant, which Cuvier distinguished as the \u201c molaire carnassi\u00e8re:\u201d the dotted line traverses that tooth which M. de Blainville distinguishes as the \u201c molaire principale : \u201d the letters and numbers symbolise the teeth and indicate their individual homologies, and the binary division of the molar series, which it has been one object of the present Article to illustrate. I shall conclude it by showing how these symbols may be applied to the exposition of facts in the comparative anatomy of the teeth, and for that purpose select the complex and intricate subject of the succession of the teeth in the kangaroo.\nThe chief modifications of the marsupial dentition are described and illustrated in the article Marsupialia ( Vol. III.pp.258\u2014298.). When that volume was published I had not had the means of tracing the period and order of the development and succession of the entire series of teeth in any of the marsupial genera. The first of the five grinding teeth on each side of the jaws of the wombat had shown, by its displacing a milk-tooth vertically, that it was a pretnolar ; and the adjoining molar, by its earlier development and use, was plainly the first of the four true molar teeth. In the carnivorous and insectivorous families, the marked difference of form and size of the last four teeth from those intervening between them and the canines, had also induced me to class them as true molars, although I had not got the developmental evidence of the fact, except in the case of the Kangaroos and Potoroos (Macropus and Hypsiprymnus). The analogy, however, seemed to be sufficient to justify the generalisation that the Marsupial differed \"from the Placental Diphyodont mam-\u201e\t.\t.\t4\u20144\nmais in having four true molars, i. e., m. ^^\n3___3\ninstead of m. -\u2014- ; and also that they differed\n\u00fc\u2014-\u00ab3\n3___3\nin having only three premolars, i. e. p.\n* Tom. iii. (1845), p. 116,\n/|,\ninstead of p. ^^ ;\n. ,.\t.\t7\u20147\ngrinding series,\n933\nthe typical number of the being the same. The\n7\u20147\u2019\ngenus Myrmecobius offered the most remarkable exception here, as the Manatee had done in the placental series, in the increased number\n8\u20148\t9\u20149\nof the grinding teeth, e. g. to ^\t^ or gUj)\u00bb\nwhich, according to the shape of the crowns, were divided, in the Myrmecobius, into p.\n2 3\tg 0\n-\u2014r, m. -\u2014- ; but the order of development o\u2014*3\to\u2014u\nand succession may show that the number of premolars is greater, and that of the true molars less. The probably marsupial T/iyfa-cotkeriuui or Amphitherium from the Oxford oolites \u2014 the most ancient of all known mammals\u2014had as many as twelve teeth in each molar series, besides a canine and three incisors, and by their form I have grouped . 3\u20143\t1\u20141\t6\u20146\t6-6 ^\nthem as : >.\tc. \u2014, p. ^, m.\nAn interesting field of observation still remains open in regard to the period and order of developement of the deciduous and permanent teeth, in the different carnivorous, omnivorous, insectivorous, and frugivorous Marsupials. At present I have ascertained the required facts only in the herbivorous family (Poephaga). The permanent dental formula ofboth the\n.\t. 3\u20143\nMacropodid\u0153 and Hypsiprymnid\u0153 is, i. ^\n1-\t1\t1\u20141\t4\u20144 Qn\n(jHo\u2019 P- TZT\u2019m' 4=4 = 30- The camnes\u2019 which are confined to the upper jaw, are small or minute when retained; and disappear after being represented \u201c en germe\u201d in most of the true kangaroos.\nThe deciduous dentition of the great Kangaroo ( Macropus major) is, i. 3\u2014y Cm 1\u20142^\n2___2\n----= 18. The canines are rudimental,\n2\u2014\t2\nand are absorbed rather than shed. The deciduous incisors are shed before the young animal finally quits the pouch : when this takes place, the dentition is : \u2014\n\u2022 1\u20141 A\t2\u20142 1\n2_ i2,\nthe upper incisors being i. 1, the molars d. 3 and d. 4 of the typical dentition. This stage is exemplified in the lower jaw at a, fig. 594. The next stage shows the acquisition of i. 2 in the upper jaw, and m. 1 in both jaws, and the formula is : \u2014\n\u2022\t2 a 2~2 \u00ab, 1\u20141\nn=\u00ef=\\ \\\nAt one year old, the dentition is : \u2014\n3\u20143 , 2\u20142\t2\u20142\nl\u2014l 2\u20142\u2019\t2\u20142\nthe additional teeth being i. 3 and m. 2 (c, fig. 594. ; in which the demonstration of the true deciduous character of d. 4 and d. 3 is shown by the germ of their vertical successor,\n* Odontography, p. 376, pi. 99.\n3 o 3\n,m.\t4 = 18. (Pifig. 594.)\n= 24;","page":933},{"file":"p0934.txt","language":"en","ocr_en":"TEETH.\nFig. 594.","page":934},{"file":"p0935.txt","language":"en","ocr_en":"TEMPERAMENT.\n935\np. 4, which is exposed in the substance of the jaw). The next stage is the shedding of d. 3, and the acquisition of to. 3 (d, fig. 594.). Then d. 4 is shed by the ascent of p. 4 into its place (e, fig. 594.). Afterwards to. 4 is acquired, and, in the Mocropus gigas, p. 4 is simultaneously pushed out (f,fig. 594.).\nThus, four individuals of this species may be found to have the same number of molars,\ni. e. -\u2014- ; two of these may seem, on a cur-4\u20144\nsory comparison, to have them of the same shape, e. g., like c and E, fig. 594 . ; or like D and f. In fact, to determine the identity or difference in such instances, it requires that the substance of the jaws be examined to see if the germs of successional teeth be present, as at p. 4, c and d, or at to. 4, e.\nThe result of such examination may be to show that not one of the four kangaroos with\nthe\nm.\n4\u20144\n4\u20144\nhad the same or homologous\nteeth. The four grinders, e.g., may be \u2014 d. 3, d. 4, m. 1, to. 2 ; as in c : or, d. 4, to. 1, to. 2, to. 3 ; as in d : or, p. 4, to. 1, to. 2, to. 3 ; as in e : or, to. 1, TO. 2, m. 3, and to. 4 ; as in F.\nBut the change does not stop here : as age advances, to. 1 is shed, and the molar series is reduced numerically to the condition of b ; but, instead of to. 1, d. 4, and d. 3, it consists of 7)1. 2, TO. 3, 771. 4.\nFinally, to. 2 is shed, and the dentition is reduced to the same numerical state as at a., fig. 594. : the teeth, however, being to. 3 and to. 4.\nThe order here described is not precisely that which is followed in some of the smaller species of kangaroo. In Macropus Bniettii, e.g.y the acquisition of to. 3 is not aceom--panied by the shedding of d. 3, but the molar\nseries is numerically -\u2014^ : 80* likewise, m\nthis species, the acquisition of to, 4 is not accompanied by the displacement of p. 4 ;\n\u00a3__g\nand a molar series of -\u2014- is long retained ; o\u2014o\nbut, at the earlier period cited, the teeth are : \u2014\nd. 3, d. 4, to. lr to. 2, and TO, 4 : and, at the lacer period, they are :\u2014*\np. 4, 77i. 1, 7)i. 2, to. 3, and to. 4, _\nThese symbols, it is hoped, are so plain and simple as to have formed no obstacle to the full and easy comprehension of the facts explained by means of them. Had those facts been described in the ordinary way, by means of verbal phrases or definitions of the teeth, \u2014 e.g., \u201cthe second deciduous molar, representing the fourth in the typical dentition,\u201d instead of d. 4, and so on, \u2014the description would have occupied much more space, and have levied such a tax upon the attention and memory, as must have tended to enfeeble the judgment, and impair the power of seizing and appreciating the results of the comparisons.\nEach year\u2019s experience strengthens my conviction that the rapid and successful pro-\ngress of the knowledge of animal structures, and of the generalisations deducible therefrom, will be mainly influenced by the determination of the nature or homology of the parts, and by the concomitant power of condensing the propositions relating to them, and of attaching to them signs or symbols, equivalent to their single substantive names. In my work on the \u201c Archetype of the Skeleton,\u201d I have denoted most of the bones by simple numerals, which, it generally adopted, might take the place of names; and all the propositions respecting the centrum of the occipital vertebra might be predicated of 1 as intelligibly as of \u201c basioccipital.\u201d\nThe symbols of the teeth are fewer, are easily understood and remembered, render unnecessary the endless repetition of the verbal definition of the parts, harmonize conflicting synonyms, serve as a universal language, and express the author\u2019s meaning in the fewest and clearest terms. The entomologist has long found the advantage of such signs as $ and <j>, signifying male and female, and the like ; and it is time that the anatomist should avail himself of this powerful instrument of thought, instruction, and discovery, from which the chemist, the astronomer, and the mathematician have obtained such important results.\n(i2. Owen.)\nTEMPERAMENT. Although all individuals of the same species are composed of the same tissues, consisting of the same elements both proximate and ultimate, and agreeing in all essential points of chemical constitution,, yet there exist between certain groups of them, sometimes in the most striking degree, differences not only in the physical powers and actions of their frames, but also in their mental qualities. These differences are refer-rible only to peculiarities in the constitution of an individual, or in other words, to peculiarities in the quality of his solids and fluids, which are of a nature so recondite that we cannot detect them by any chemical or ana, tomical means, and we appreciate them only by the character with which they impress the physical and, to a certain extent, mental actions of the individual in which they exist. To express this character in one word physiologists employ the term temperament,\nThe use of this word is of very ancient date. We trace it as far back as the time of Galen, who broached the doctrine that the blood consisted of four humours, correspond, ing to the four elements.; these were respec, tively designated bills, sanguis, atm bibs? phlegmet. Nunc, says Haller, ex ejusmodi quatuor humoribus sanguinem aiebant tempe-rari, justamque omnium principiorum commis-tionem perfeetissimum temperamentum efficere; si vero aut sanguis supra l\u00e9gitimant suam quasi dosin abundaret, sive bilis, sive terra atrave bilis, sive phlegma, quatuor tunc sim-. plicia et pr\u00e6cipua temperamenta aiebant oriri, a bilis abundantia cholericum, ab aqu\u00e6 uber-tate phlegmaticum, a sanguinis aucta portione","page":935},{"file":"p0936.txt","language":"en","ocr_en":"936\tTEMPERAMENT.\nsnnguineum, et denique a copia atr\u00e6 bilis me-lancholicum.*\nThis view of the doctrine of temperaments prevailed in the schools down to the time of Cullen, and we find that able and thoughtful physician thus expressing himself upon the subject : \u201c The ancients very early established a distinction of temperaments which the schools of physic have almost universally adopted ever since, and appears to me to be founded on observation. I am very much of opinion, that we can perceive a combination of a particular state of the chief circumstances of the economy to take place very steadily in certain persons, and thereby to form at least two of the temperaments assigned by the ancients.\u201d f\nThe temperaments, the existence of which seems most consistent with observation, are those admitted by Cullen, namely, the sanguineous and the melancholic, the phlegmatic being a degree or modification of the sanguineous, and the choleric of the melancholic.\nIt is reasonable to expect an infinite variety as regards the extent to which the characteristic marks of the temperaments are manifested in various individuals. Taking examples which afford good indications, the two temperaments above referred to may be described as follows, after Cullen.\nIndividuals of the sanguine temperament have the quantity of fluids in the body large in proportion to the solids, the habit of body soft and plump, after the period of manhood disposed to obesity, and at all times, readily sweating upon exercise, the skin smooth and white, the hair soft, generally of a pale colour or from thence passing through different shades to a red ; the complexion ruddy, the eyes commonly blue ; the strength of the whole body is moderate, and the mind sensible, irritable, cheerful, and unsteady. The most exquisite examples of this temperament are found in men from the time of puberty to that of manhood, and in women. In both sexes the characteristics of the temperaments are far less manifest in old age.\nIn persons of the melancholic temperament the habit of the body is rather hard and meagre, the quantity of fluids in the whole system moderate in proportion to the solids, the simple solids firm and dense, the hair hard, black, with a tendency to curl, the skin coarse, of a dun colour, with a corresponding complexion, the eyes very constantly black, the strength considerable, the mind slow, disposed to gravity, caution and timidity, with little sensibility or irritability, but tenacious of all emotions once excited, and therefore of great steadiness. This temperament is most completely formed in advanced life, but the characters of it appear often very early.j;\nBy some writers a nervous temperament is admitted, the prominent characteristic of which consists in a great excitability of the nervous system, and a predominance of\n* Haller, El. Physiolog. lib. v. sect. 4.\nf Mat. Med.\nX Cullen, loc. cit.\nemotional impulses over the influence of the will. Individuals of this temperament are generally fidgetty and restless, take but little sleep, and are anxious about trifles ; they are called \u201c creatures of impulse ; \u201d their emotions are easily excited, and often not readily subdued. In persons of this temperament, when labouring under disease, phenomena referrible to the nervous system are very apt to complicate and often to obscure the morbid actions. This temperament, however, cannot be said to exist apart from the sanguineous or melancholic : it always accompanies either one or the other, most frequently the former, and the most exquisite examples of it are found in the female sex.\nIn looking at the physical conditions of the best-marked examples of the sanguine and melancholic temperaments, it is important to ascertain whether any one property or quality stands out more prominently than the rest, which might seem to give to the whole economy of the individuals its peculiar cast. It appears to me that there is no single physical property which is so closely associated with difference of temperament as variety in the quantity, and perhaps also in the kind, of colouring matter or pigment, evinced by the colour of the hair and skin, and influencing also the colour of the eyes, and of the blood, and of the nervous centres.\nIndividuals of the melancholic temperament exhibit in their various tissues a considerable amount of pigment, as shown by the dark colour, generally black, of the hair and eyes, while on the other hand those of the sanguine temperament are deficient in colour, having light hair, blue or grey eyes, and fair or white skins. Observations are yet wanting, in sufficient number, to determine the relative amount of colouring matter in the blood of individuals of each of these temperaments, or to ascertain whether it is characterised by any peculiar chemical qualities. It seems highly probable that the amount and kind of colouring mutter in the skin, hair, and eyes, as well as of that in some of the secretions, as bile, urine, &c. is influenced by the amount and kind of the haematine.\nThe xanthous and leucous races of man inhabiting for the most part cold or temperate climates, afford the most numerous examples of the sanguine temperament, while the me-lano-comous or dark races found chiefly in warm climates are mostly of the melancholic temperament. And those individuals of the xanthous and leucous races, which in physical characters approach most nearly to the dark races, as by the existence of a large quantity of dark pigment in their tegumentary tissues, are of the melancholic temperament, whilst the light-coloured members of the xanthous races are prone to exhibit the characters of the sanguine temperament.\nIf it be admitted that a constant connection exists between colour and temperament, as I think is sufficiently obvious, it would follow that the nature of the temperament is determined by certain peculiarities in the physical","page":936},{"file":"p0937.txt","language":"en","ocr_en":"TEMPORO-MAXILLARY ARTICULATION.\t937\ncondition of the frame. These peculiarities react to a certain extent upon the mind, and more or less aid or clog its workings, but certain powers and modes of action of the mind are by no means so constantly associated with certain states of body, as to connect the mental and bodily states as cause and effect. It is true that the sanguine temperament is generally accompanied by a mind exhibiting certain characters, but the exceptions to this are so numerous that we cannot assign the corporeal state as the cause of the mental \u2014 nor vice versa. Bodily peculiarities are infinitely more frequently inherited than mental, \u2014 the powers and activity of the mind are greatly determined by education and training; but those qualities of body which give a character to its temperament are born with it ; and although they may be modified by external influences, they are yet at all times sufficiently distinct to prove them to be inherent physical properties of the entire organism.\nAt the same time it seems reasonable to admit that the mind has its temperaments, as the body has, and in a great measure independently, and the terms, sanguine, melancholic, phlegmatic, and choleric, may be severally applied to them, according as the emotions and feelings, and the intellectual actions vary in their modes and degrees of developement, and in their rate of working.\n(R. B. Todd.)\nTEMPORO-MAXILLARY ARTICULATION.\u2014Under this heading I propose to give a brief account of the jointing of the lower maxilla to the cranium. This joint cannot, of course, be identified out of the verte-brata. The mandibles and maxillae of the ar-ticulata are not homologous with the jaws of vertebrate animals, and the slit of their mouths is placed vertically not horizontally.\nIn the human subject, as in all mammalia, this articulation takes place between the squamous portion of the temporal (squamosal) and the inferior maxillary bones. The description of the anatomy of the human temporo-maxillary joint comprises, therefore, that of the diarthro-dial articular surfaces of those bones, and also of the following parts : viz., the interarticuiar fibro-cartilage, the two synovial sacs, the external and internal lateral and other ligaments, and part of the insertion of the external pterygoid muscle.\nBones. \u2014 The articular condyle of the lower jaw is sub-cylindroid in form, its length from side to side being greater than its antero-pos-terior measurement. The axis of this cylinder, however, is set neither directly from side to side, nor yet exactly level, its inner part being posterior to and below its outer; so that if the axes of the tw'o condyles were produced inwards till they met, they would form an angle in doing so, which would point downwards and backwards,\u2014reaching the anterior margin of the foramen magnum. The cartilage that encrusts this condyle extends further down behind than in front.\nThe surface to which this condyle is\n(mediately) articulated forms a part of the glenoid fossa, and is situated just below the base of the zygomatic process of the temporal bone, between its roots. It has such form as, in respect of the set of its axis, and its tranverse measurement, pretty accurately fits the condyle. It has, however, a greater antero-posterior extent, in accordance with the capability which this joint normally possesses, in addition to the usual ginglymoid motion, of an antero-posterior gliding to and fro of the condyle\u2014a kind of normal dislocation. The glenoid fossa of the temporal bone contains a portion of the parotid gland, as well as the condyle of the inferior maxilla ; the former occupies that portion of it which is posterior to the glasserian fissure, whilst that part which is anterior to the glasserian fissure, is lined with cartilage for the articulation of the latter. In man there is usually no bony ridge bounding this articular surface posteriorly, such as is generally found in the lower mammalia.\nThe ridge that bounds it anteriorly is formed by the inferior root of the zygoma, and the cartilage is continued some way on to this ridge. Externally it is limited by a tubercle on the zygoma, which serves for the attachment of the external lateral ligament of the joint.\nInterarticuiar fifoo cartilage. \u2014 This is a thin disc or meniscus, oval or sub-oblong in form, concave below and convex above, thus capping the condyle, thicker at the edges than in the middle, where it is not unfrequently thinned away even to perforation. It differs from all the other fibro-cartilages in having muscular fibres inserted into it; namely, a portion of those of the external pterygoid. This insertion takes place along its anterior border, and by it the fibro-cartilage is made to join in that normal amount of dislocation forwards, which as above stated, the condyle of the lower maxilla is capable of, as well as in the abnormal accidental dislocation of the jaw. It is further held in its place by the fibres of the external lateral ligament, and by the synovial bursae of the joint.\nSynovial Bur see.\u2014 These are two in number, one above the interarticuiar fibro-cartilage and the other below it. The upper one is the larger and slacker, for it alone is concerned in the antero-posterior gliding of the joint. The two sacs, of course, communicate and are reduced to one when the interarticuiar fibro-cartilage is perforated in the centre.\nLigaments.\u2014There is only one ligament in immediate relation with the temporo-maxillary joint, namely, the external lateral. This is a small ligament, broader above than below, situated at the outside of the joint; attached above to the tubercle situated at the point of divergence of the roots of the zygoma ; and directed downwards and backwards to the outside of the neck that supports the condyle of the lower jaw. Midway in its passage from the one to the other it is attached by its inner aspect to the interarticuiar fibro-cartilage.","page":937},{"file":"p0938.txt","language":"en","ocr_en":"938\tTEMPORO-MAXILLARY ARTICULATION.\nThe internal lateral ligament is a long thin slip extending from the spinous process of the sphenoid, and the neighbouring parts of the temporal bone to the fore part of the lip of the inferior dental canal. It lies behind the external pterygoid muscle, by the origin of which its cranial attachment is concealed, and it is separated from the temporo-maxillary joint by a considerable space through which pass the internal maxillary artery and vein, giving off their middle meningeal and inferior dental branches, which indeed are conducted, the former to the foramen spinosum of the sphenoid, the latter to the inferior dental canal, by the ligament in question.\nNumerous stray fibres of ligamentous tissue strengthen the synovial sacs of the temporo-maxillary joint, forming a kind of capsular ligament.\nThat process of the cervical fascia, which is called the stylo-maxillary ligament, is generally enumerated as one of the ligaments of this joint. It extends from the styloid process to the lower part of the ramus of the jaw, separating the parotid from the submaxillary gland, and affording attachment to the styloglossus muscle. The condyle of the lower jaw depends for the maintenance of its normal apposition to the temporal bone much more upon the masseter, temporal and pterygoid muscles than upon these small ligaments ; by these, however, its astero-posterior gliding is indifferently tethered.\nMuscles. \u2014 The external pterygoid-muscle, proceeding backwards and outwards from its origin, is mainly inserted into the front of the neck that supports the maxillary condyle, the upper part of it, however, is inserted into the interarticular fibro-cartilage, which thereby is drawn forward along with the condyle when this muscle acts. This insertion is tendinous.\nMotions of the joint. \u2014 The temporo-maxillary joint admits of a ginglymoid motion in the vertical direction, by which the mouth is opened and shut. This motion must of necessity always take place in the joints of both sides at the same instant. It also admits of a horizontal antero-posterior gliding motion, in which the joint of one side only may be mainly concerned. In the human subject the front teeth of the lower jaw, in most cases, are not exactly opposed to those of the upper jaw\u2014that is, the summits of the one set are not applied to the summits of the other \u2014 in the ordinary position of the mouth, either when at rest or engaged in mastication. The lower incisor teeth are usually posterior to the upper. But when we bite with the front teeth we bring the upper and lower set into apposition by thrusting forward the lower jaw : in this act both joints are similarly concerned. We can also execute a grinding motion from side to side, and this is done by thrusting forward one condyle whilst the other merely revolves on the axis of its neck.\nThe jaw is elevated or closed by the temporal, masseter, and pterygoid muscles. The pterygoid, chiefly the external, are the agents in protruding it. These latter are antagonised\nby the elevating and also by the depressing muscles. The chief depressor of the lower jaw is the digastric, as is clearly shown by its comparative anatomy, but all those which extend from the chin to the hyoid bone are capable of, and occasionally do assist in performing this act.\nThe majority of the muscular fibres that elevate the jaw arrive at their insertion into it from before backwards ; thus the masseter has a kind of twist in the arrangement of its fibres, so that those which arise most anteriorly are inserted very conspicuously furthest back, whilst the remainder proceed directly downwards or slightly forwards ; a considerable portion of those of the temporal, namely, those which arise from the anterior part of the temporal fossa, run backwards to their insertion into the coronoid process. The use of this arrangement seems, upon a careful consideration of the mechanics of the question, to be the application of the elevating or closing force in a more favourable direction, not, as might seem at first sight, the protrusion of the lower jaw \u2014 that is amply effected by the pterygoideus externus.\nAbnormal conditions of the temporo-maxillary joint.\u2014Accidents.\u2014 The condyle of the lower jaw can only be dislocated in one direction, namely forwards. In this accident the condyle slips forward over the inferior root of the zygoma, and is then drawn somewhat upwards within the zygomatic arch. The interarticular cartilage is carried with it. Thisusually happens to the joints of both sides, but occasionally one condyle only is dislocated. It is usually produced by the action of the muscles when the mouth is very widely opened, as in yawning, or more especially in biting a very large object, such as a large apple.\nWhen both the condyles are dislocated, the lower jaw is thrust forwards and cannot be retracted. The mouth is widely open and the patient is unable to close it. The power of swallowing is lost, and the saliva, the secretion of which is probably increased, flows from the mouth involuntarily. Articulation is difficult, owing to the impossibility of making the labial sounds. There is a conspicuous depression beneath the zygoma just in front of the ear, and a flatness in the masseteric region. The coronoid process is much depressed, and forms a visible protuberance beneath the zygoma, and, as first observed by Mr. Adams of Dublin, there is a prominence in the temporal region between the eyebrow and the ear, produced by the posterior fibres of the temporal muscle being pushed up by the condyle in its new position.\nIf this dislocation remains unreduced, the parts, as in most other dislocations, gradually accommodate themselves to their new position, so that the power of articulation and deglutition is re-acquired, the mouth can be closed, and a considerable amount of motion is regained, but the chin remains abnormally thrust forwards, and there is always a depression in the position normally occupied by the condyle.","page":938},{"file":"p0939.txt","language":"en","ocr_en":"TEMPORO-MAXILLARY ARTICULATION.\n939\nWhen one condyle only is dislocated, the chin is thrust forwards and towards one side \u2014that, namely, on which the condyle remains in place. The coronoid process of the dislocated side forms a prominence even more conspicuous than when both condyles are displaced, but the mouth is not so wide open. There is, of course, the same depression in front of the ear, and the same flatness of the masseteric region.\nCongenital malformation, Dr. R. W. Smith of Dublin, in his Treatise on Fractures and Dislocations,* gives a detailed account of the dissection of a highly interesting case of \u201c Congenital luxation of the inferior maxilla.\u201d The malformation affected one side only, \u2014 the right,\u2014 and consisted mainly of an absence, or arrest of development of the condyle, the only vestige of which was a small process hooked inwards at its apex. This process did not touch the temporal bone by a quarter of an inch, and neither it nor the surface opposite to it presented any articular cartilage, but were both simply invested with periosteum. There was no trace of an interarticular fibro-eartilage, nor of a synovial sac, and the external lateral ligament sloped downwards and forwards instead of downwards and backwards. The glenoid cavity did not exist, or rather the inferior root of the zygoma, which really forms the glenoid cavity, was not developed. There was conspicuous atrophy of the whole of this side of the face in respect of the bones \u2014 temporal, right half of the body and right ramus of the inferior maxilla, malar, superior maxillary, and even the right half of the sphenoid, \u2014 and muscles, but the nerves were as large as their fellows. The most remarkable of the peculiarities of the surrounding parts, and that which clearly demonstrated the abnormal condition not to be the result of injury or disease, was an extreme shortness of the zygomatic process of the the temporal and a compensatory unusual length of that of the malar bone. The former was only half an inch long, whilst the latter was nearly twice as long as that of the other side. During the lifetime of this patient, who was an idiot, it was observed that one side of his countenance did not match the other, and that the disparity was much increased when he opened his mouth. He was often observed to have spasmodic twitching of the abnormal side of his face.\nDisease. \u2014 Chronic rheumatic arthntis occasionally affects this articulation. Both joints are usually affected by it, but sometimes it attacks the joint of one side only. It is most common in elderly subjects. When it attacks the young or middle aged, it is more rapid, accompanied with more pain, and more likely to involve the neck of the condyle and the ramus of the jaw. The pain is often very severe but variable, apparently influenced by meteorological changes. The lymphatic glands in the neighbourhood of the diseased joint are much prone\n* A Treatise on Fractures in the Vicinity of Joints and on Certain Forms of accidental and congenital Dislocations. Dublin, 1847. 8vo.\nto enlargement; and sometimes the enlarged condyle can be felt as a bony tumour just in front of the ear. The chin is thrust forward, mesially when both joints are affected, and towards the healthy side, as well as forwards, when only one is diseased. The motion of the jaw is considerably impaired. On dissection, the condyle, in cases of this affection, is generally found to be large and broad, but sometimes conical, rough, and devoid of cartilage. Ivory or porcellanous deposit, so common in other joints when affected with chronic rheumatic arthritis, is but rarely met with in this ; those abnormal ossifie concretions in and around the joints, which are so constantly met with in the disease in question in other situations, have also never been found in the temporo-maxillary joint. The interarticular fibro-cartilage had disappeared in every case of this affection which has been dissected and published. The gleqoid cavity is enlarged, divested of its articulai- cartilage, and presents a roughened, abnormal surface. All indication of the disease stops suddenly at the glas-serian fissure, and at the spheno-temporal suture, and the enlargement of the glenoid cavity takes place at the expense of the lower root of the zygoma which generally becomes entirely absorbed.\nIn the report of the proceedings of the Pathological Socety of London in the Medical Gazette of November 30. 1849, there is an account of a highly interesting case of necrosis of the condyle, back part of the ramus, and angle of the lower jaw in a scrofulous boy. The portion of necrosed bone, which was exhibited to the society, was removed many years before, by Mr. Keate, who also had examined the patient, grown to a healthy man, two years before the date of the communication. As far as could be ascertained by external investigation, the lost portion of bone had been perfectly restored. There was no deformity, and no impairment of motion. There are two other similar cases on record ; one by Desault, in which the whole ramus, with the condyle and coronoid process, were removed, the other by Mr. Syme, in which the condyle and ramus were necrosed. In both these cases, also, the lost bone was perfectly restored to all external appearance, but there is no record of a dissection of such a case. In some cases which are on record, where the whole of the lower jaw, with both its condyles, has been removed, its place has been supplied by condensed fibrous tissue, but there has been no reproduction of bone.\nAnchylosis of the temporo-maxillary joint is a very rare occurrence. There is, however, one specimen of it in the Pathological series of the Museum of the London College of Surgeons. The fusion of the two bones is complete, as is shown in the preparation by a vertical, side to side, section through the situation of the quondam joint. This section shows that a perfectly normal-looking cancellous structure, shelled over by a layer of dense osseous tissue, is continued from the temporal to the inferior maxillary bone, and exhibits no","page":939},{"file":"p0940.txt","language":"en","ocr_en":"TEMPORO-MAXILLARY ARTICULATION.\n940\nmanner of trace to indicate where the joint once was. In fact this anchylosis had existed for fifty years before the death of the patient. No record is preserved of the cause of it. The joint of one side only is anchylosed, but that of the other side is much altered in form. An abnormal tubercle of bone projects downwards from the middle of the glenoid cavity and is received into an abnormal excavation or alveolus in the middle of the condyle. The lower jaw is much wasted in size, and has lost all its teeth save the two front incisors. The upper jaw bones are thin and light.\nThe motion of the lower jaw is often lost owing to an affection not immediately connected with the joint itself. When, as often happens in scarlatina, cancrum oris, &c. there is extensive sloughing of the inside of the cheeks, the cicatrices resulting from the healing of the great wounds contract, and form bands, extending from the upper to the lower jaw, so strong and unyielding that the muscles which open the mouth are unable to antagonise them.\nComparative Anatomy.\u2014If a palaeontologist were asked what fragment of a vertebrate skeleton, speaking generally for all ver-tebrata, would give him most information as to the status and affinities of the animal to which it belonged, he would most probably answer \u2014 the articular portion of the lower jaw or the articulation that receives it. Of the convex and concave surfaces which go to form this articulation, in all the mammalia the convexity is on the inferior maxilla, and the concavity on the squamosal bone, whilst in the three other vertebrate classes the reverse is invariably the case \u2014 the concavity is on the inferior maxilla, the convexity on the bone that articulates with it.\nThe under jaw does not articulate with the same, or to speak more accurately, with the homologous bone in all vertebrate animals. In all the mammalia it articulates, as in man, with the squamous element of the temporal \u2014 the squamosal bone. In birds, reptiles, and osseous fishes it articulates with bones which are clearly the special homologues of the tympanic ring of the human subject. In cartilaginous fishes its articulation is with the pterygoid bone, the homologue of the human internal pterygoid plate. The Lepidosiren, in which so many other characters of the osseous and cartilaginous fishes are so curiously blended together, in strict accord with this circumstance, presents an instance of the pterygoid and tympanic bones contributing each a part \u2014 the former the inner, the latter the outer part, of the articular surface for the reception of the lower jaw.*\nIt is well worth while to stop here and review what is stated in the two preceding paragraphs. What is said is, really, this ; \u2014 every animal that sucklesitsyoung has a convex articular surface to its lower jaw, whilst every vertebrate that lays eggs has a concave surface. Or this\u2014every vertebrate animal that\n* Owen.\nhas hair upon it, that has a diaphragm, or an epiglottis, has a convex articular surface to its lower maxilla, whilst all vertebrates that are destitute of these have a concave surface. Or, again, all animals that suckle their young, and have diaphragms, hair, and epiglottides, present their squamosal bones for the articulation of their inferior maxillae, whilst all in which the possession of these characters is negatived present for this articulation their tympanic, or, rarely, their pterygoid bones. Can any physiological reason be assigned for this ? Can any final purpose, holding good in all, or in the majority of, instances, be shown to be served by this difference ? I think none can. One cannot conceive but that it is a matter of perfect indifference whether the convexity is on this bone or that. Let us look once more to the facts. The bat that flies, but not the swallow, the whale that swims but not the cod-fish, the camel that walks the desert, but not the ostrich, the carnivorous lion, seal, and weasel, but not the eagle, penguin, crocodile, and shark, have convex articulations to their lower jaw and present to them their squamosal bones. Here then is a caveat for the physiologist. A character found in an animal may have no physiological signification,\u2014no relation to external circumstances, nor even a functional connexion with, or dependence on other characters wherewith it coexists, perhaps invariably. It may be due to the status only of the animal. Physiologically independent it may exist in an animal only because other independent characters co-exist. It may be a Syneilogy, not a Teleo-\nloSV-\nThat certain independent characters invariably go together, which was so elaborately illustrated by Cuvier, is a fact of a high order, perhaps the twilight of some great truth. If future investigations should prove that truth to be progressive developement, towards which hypothesis the inquirer is, even now, tempted by so many striking facts, as well as by the admirable use that can be made of it as a scaffold theory, then we should say, and as making use of a scaffolding we may say it now, that certain characters are attained to at a certain stage in the chain of development, and, therefore, those are found coexisting which are proper to the degree of development to which the animal has arrived. Such characters I have been accustomed to call Syneilogies *, a word which at all events has the merit of referring only to a well known fact, without involving any hypothesis. To the palaeontologist this \u201c correlation of independent characters \u201d f is, of course, invaluable, and for the purpose of arranging natural groups in the animal kingdom, these, so to speak, useless, or Syneilogical, characters are immeasurably more valuable than those modifications to meet special exigencies which are called teleologies.\nMammalia. \u2014 In all mammalia, except man, the articular surface on the squamosal bone is bounded posteriorly, or, in the rodents, inter-\n* rvv, \\6yt>t.\n\u25a0j- Cuvier.","page":940},{"file":"p0941.txt","language":"en","ocr_en":"TEMPORO-MAXILLARY ARTICULATION.\t941\nnally, by a prominent ridge or process. This is the case in the higher Quadrumana, and there is an indication of it even in the lower races of mankind. In the Carnivora the condyle is in general extremely long, cylindroid, and its length is set, almost or quite directly from side to side, whilst the surface to which it is opposed is bounded by a very salient ridge fore and aft. This condition attains its acme in the Badger, where the salient ridges, especially the posterior, even arch over and surround the cylindroid condyle so much, that in the dry skull the lower jaw remains attached to the cranium without any artificial contrivance, and can be removed only by slipping each half out sideways when the symphysis has been disjoined. With such a joint there cannot, of course, be the usual lateral motion of the jaw. In the Rodentia, on the contrary, the long diameter of the condyle is directed antero-posteriorly, and is adapted to an antero-posterior groove, mostly bounded, internally and externally, by salient ridges. Hence that nibbling, antero-posterior motion of the jaw, which is so conspicuous in these animals, and with which their teeth and masticatory muscles are in such admirable relation. This only holds good in respect of the placental rodents. In that great marsupial rodent, the Wombat, the saliently arched, cylindroid condyles have the usual side to si le and converging-behind set of their long diameters. The articular surface which is opposed to this condyle is placed, as in the placental rodents, on the zygomatic process, which in both runs almost directly outwards ; instead, however, of being an antero-posterior groove it is a transverse convex cylindroid, describing a retreating curve ; so that in the ternporo-maxillary joint of the wombat a cylindroid ridge is opposed to another cylindroid ridge, the one describing a salient, the other a retreating arch.* The articular facets of the temporo-maxillary joint in the Ruminantia approach more nearly to plane surfaces than in any other animals. The squamosal facet is bounded by a ridge posteriorly, but has no bony limitation in front. This is in relation with the extensive lateral movement of the jaw which these animals use in chewing the cud, and with the limited power of gaping which they possess. The rest of the mammalia present varieties in this joint which are extremely interesting, but an account of them would occupy more space than the limits of this work permit.\nAves. \u2014 In birds, as above stated, the articular surface of the lower mandible is concave, and is adapted to the tympanic bone, or, as the older ornithologists called it, the os quadratum.f The articular surface of the lower jaw presents two concave depressions. The tympanic bone is itself moveable, being articulated to the cranium by two diarthrodial joints, so that a bird\u2019s lower jaw is swung to the head by two moveable jointings.\n* See Art. Marsupialia, fig. 94.\nf See Art. Aves.\nReplilia. \u2014 The evenly concave articular surface of a reptile\u2019s lower jaw is often contributed to by more than one of the osseous pieces which compose the inferior maxilla of the oviparous vertebrates. In the crocodile by two, in some chelonia by three of these pieces. The tympanic bone is articulated with the other cranial bones by suture, and is therefore immoveable, in the Crocodi/ia and Chelonia, but it is articulated with them by diarthrosis, and therefore moveable, in the Lacertia, Ophidia, and Batrachia. In some ophidia, as the Python, there being, properly speaking, no symphysis of the lower jaw, but instead of it an elastic ligament, holding the two halves together at the chin, one temporo-maxillary joint is capable of movement independently of the other. In the Batrachia, among their many fish-like characters is that of a dismemberment of the tympanic bone, which consists of an upper and a lower piece.\nPisces. \u2014 In the majority of fishes, the tympanic bone is represented by four separate pieces called epi-, hypo-, meso-, and pr\u00e6-tympanic bones. These, further, bear upon their posterior edge three opercular bones, which were considered by Geoffroy St. Hilaire to be the homologues of the ossicula auditus, but are regarded by Prof. Owen as appendages, serially homologous with the costal appendages. The uppermost piece, the epi-tympanic, articulates by a diarthrodial joint with the mastoid, and the lowermost, hypo-tympanic, presents a diarthrodial convexity to the lower jaw. The four tympanic pieces articulate with one another, and with the opercular bones by the interposition of ligament, or rather membrane, connecting their thin adjacent edges together, so that the whole apparatus is capable of bilging outwards in the movements of respiration. In the eel tribe (Mur\u00e6nid\u00e6) the number of tympanic bones is reduced to three, which is obviously an approach towards the two tympanic pieces of the Batrachia. The formation of the cranial part of the joint in question by the pterygoid and tympanic bones conjointly, in the Lepido-siren has been mentioned above. In the Sharks and Rays the tympanic pedicle descends upon that part of the pterygoid which forms the joint, but does not actually reach the articulation, the pterygoid being interposed. In these fishes, the super-maxillary and pterygoid pieces being confluent, and both bearing teeth, it appears at first sight that the whole upper jaw is formed by the former alone, consequently that the inferior maxilla is articulated directly with the super-maxillary ; such an articulation, however, never takes place in any animal.\nThe interarticular fibro-cartilage is constantly met with in Mammalia, but in neither of the other vertebrate classes.\nHomology of the joint. \u2014 The joint in question is the articulation between the pleura-pophysis and the h\u0153mapophysis of the frontal vertebra. It is therefore serially homologous with the joint between the rib and the costal cartilage of mammalia, or the vertebral and sternal ribs of birds and reptiles.","page":941},{"file":"p0942.txt","language":"en","ocr_en":"TERATOLOGY.\n942\nThe joints connected with the maxillary apparatus of some of the animals belonging to the three lower sub-kingdoms are, as was stated in the beginning, not homologous with this joint, although identical in function. For description of these parts see the articles Annelida, Arachnida, Cephalopoda, Cir-rhopeda, Crustacea, Echinodermata, Entozoa, Insecta, Myriapoda, and Roti-FERA.\n(S. R. Pittard.)\nTERATOLOGY. \u2014 Under this name, which we owe to Geoffroy St. Hilaire, we understand the doctrine of congenital deformities* In a scientific sense, it constitutes a part of Pathological Anatomy, and demands our interest as much as the knowledge of those other deviations from the normal state, which is ordinarily regarded as constituting that science. In fact, pathological anatomy comprises all the anomalies of the organization ; those which occur during intra-uterine life are called congenital, and those which arise during extra-uterine life acquired. We refer to the former the imperfections of the primitive formation, or what we call monstrosities. They are those deviations of the organism which can be formed only in the earliest periods of gestation, or, at least, previously to the termination of the foetal condition.\nThe opinions now held with respect to these malformations differ widely from the absurd notions which influence the descriptions given of them by Aldrovandi, Ambrose Par\u00e9, Licetus, Palfin, and Rueff. Formerly, indeed, each monstrosity was considered as the presage of some misfortune, the warrant of divine vengeance, the effect of witchcraft, &c. Lycosth\u00e9nes used to go so far as to add to the description of each monster the picture of some calamity which was to be its sequel. To that opinion they owe their name, derived from the Latin verb monstrare.\nTheir aetiology was not less strange and incorrect. Rueff) in 1580, devoted a whole chapter to the inquiry, \u201c An homines ex d\u00e6-monibus et rursus daemones ex hominibus infantes concipere possunt ? \u201d and Casparus Schottus treated the subject in about the same style.f\nThey both give negative answers to the question, trusting to have proved by this means that monsters are not procreated by sexual intercourse of women with the devil. Other writers have endeavoured to explain the cause from copulation with brute animals, or with pregnant or menstruating women. Notwithstanding our more enlightened modern ideas on this subject, the origin of monstrous births remains still very mysterious. The opinions concerning it may be reduced to two main\n* From Ts\u00e7at?, monster ; and science.\n+ I. Rueffus de Coneeptu et Generatione Hominis. Francof ad M. 1580. P. Casparus Schottus e Societate Jesu, Physica curiosa, aucta et correcta, sive Mirabilia Natur\u00e6 et Artis. Lib. i. \u00a7 xxii.\npoints: 1. To the original malformation of the germ ; 2. To the subsequent deformation of the embryo by causes operating on its development.\nI.\tOriginal malformation of the germ. \u2014 If, according to the opinions generally adopted at the present time, the germ may be considered as a product of secretion by the female organism, upon which the male sperm acts with its material and vital influence, we may suppose that this germ may be originally malformed, owing to some influence proceeding either from the female or from the male sex.\n1.\tSuch a primitive malformation of the germ seems to exist in those cases in which the same kind of monstrosity is repeatedly procreated by the same parents. The cause may be ascribed : \u2014\na.\tTo the mother. \u2014 It is a very important fact that, in such cases, various degrees of the same species of deformity are frequently produced in successive progression, so that the first born child is the most deformed; and in the following children the deformity progressively decreases, ,and finally disappears in the last born (G. Vrolik, Vering). Sometimes a deformity of the mother is communicated to her offspring ; for instance, congenital luxation of the femur.\nb.\tTo the father. \u2014 Experience proves that a well-formed man may procreate with different women children with the same malformation (Meckel, Luber), and that a deformity of the father may be transmitted to the child (Burdach, Osiander). The last is however rare.\n2.\tA second proof in support of the probability of an original malformation of the germ is found in hereditary deformities extending over more than one generation, viz. hare-lip, excessive number of fingers, hypospadias, &c.\n3.\tA third proof may be deduced from the possibility that the ovarian ova in mail arid in the lower animals may be already malformed (Bischoff).\nII. Deformation of the originally well-formed germ.\u2014 J. It is said that this may be produced by mental impression of the pregnant woman, or what the German authors call das Versehen. But for this opinion no positive proof can be afforded. According to the observations published thereupon, and of which a great deal may be found in the learned article Generation of this Cyclopaedia, all the supposed mental impressions, which have been considered as the cause of malformations, took place, with few exceptions, in the last stage of pregnancy.* And even in those cases in which an earlier period may be certified, we could object that the post hoc must not always lead to the conclusion eigopropter hoc. It is of some importance to appreciate the correctness of this\n* See my publications in Tijdschrift v. Natuur-lyke geschiedenis en Physiologie, d. iv. bl. 221, en tolgy. en Ilandb. d. Ziehtch. Ontlurh. d. i. bl. 339.","page":942},{"file":"p0943.txt","language":"en","ocr_en":"TERATOLOGY.\t943\nreasoning, for the theory of the mental impressions, which was so readily adopted in the barbarous middle ages, as a mode of saving poor and innocent women from torture and stake, finds even in the present day more advocates than might have been expected. Of this I was convinced at the Congress of Naturalists at Aix-la-Chapelle in 1847, and in the Report of the Transactions of the Schweizerischen Naturf. Gesellschaft zu Chur, 29, 30, 31 Juli, 1844, in which the affected mind of the pregnant woman is said to produce a mysterious effect on the foetus, and that the medium by which this influence is communicated may be the hearing as well as the sight ! To crown all these absurdities, we see mentioned in Rust, Magasin, B. xxi. S. 261 that a woman gave birth to a child with imperfect bones, which is attributed to her having been present, before her pregnancy, at the execution of a criminal by breaking on the wheel. To all these fantastical considerations I oppose the following arguments : \u2014\na.\tThat malformations seldom, or perhaps never, agree with apprehensions or fears \u00e0 priori of pregnant women (G. Yrolik, T. Zimmer, J. J. Plenck, and Burdach). On the contrary, it often happens that a woman who has once procreated a malformation, and is continually troubled by the fear of another similar sad occurrence, may become the happy mother of a second well-formed child.\nb.\tThat the foetus, even when a germ, is quite independent ; transferred from the ovary into the uterus, it needs for its developement a material intercourse with the maternal body, but no organic connection ; for which reason it can be formed as well without as within the uterus, as in extra-uterine pregnancy ; that it stands in no connection, either vascular or nervous, with the body of the mother, and that therefore it is improbable that her mental condition can have any influence whatever upon the form of the foetus.\nc.\tThat malformations occur likewise among the inferior animals,\u2014insects, testaceous animals, echinodermata,\u2014in which the developement of psychical life is very imperfect, and the oviparous generation of which must preserve the young from the influence of disordered maternal imagination.\nd.\tThat in the case of twins, as the ace-phali specially show, one child may be malformed and the other in perfect condition, notwithstanding they were both exposed to the same influences.\ne.\tThat more deeply situated organs, the very existence of which may be unknown to the pregnant woman, may be malformed ; as for instance, the heart, the intestinal tube,&c.\nIf now, on all these grounds, I exclude the mental impressions of pregnant women from the aetiology of malformations, I do not mean to deny the influence which by her somatic condition the mother may exercise upon the foetus. Thus, if in consequence of mental agitation, her body were to suffer a violent shock, this might have a prejudicial influence on the material transmission which takes place\nbetween her and the foetus, and the latter might thereby become morbidly affected. There are instances of its being the subject of intermittent fever (P. Russell) ; of sudden death occasioned by frightful agitation of the mother (Wienholdt) ; of jaundice communicated by the mother (Kerckring) ; of small-pox (Jenner, Montgomery, Friedlander) ; of syphilis and scarlet fever (R. Lee), all derived from the mother. But ail this is entirely different from the effect of mental impressions. It is a material result, easily conceived, and of which physiologists need no further explanation.\n2.\tA second cause of malformation of the foetus is sought in external injury suffered by women during their pregnancy. Meckel goes so far as to reject this entirely. In some deformities, for instance, in hydrops ventrieulo-rum cerebri, the effect of external injury is easily proved.\n3.\tA third cause is attributed to diseases of the ovum and of the foetus. Simpson (Edinburgh Med. and Surg. Journal, No. 127., April, 1836, and Gazette Medicale de Paris, Nov. 1836, p. 393.) has described an acute and chronic form of placentitis, to which ought to be ascribed all those singular exudations which attach themselves to the foetus as pseudo-membranes. Fig. 595. gives a specimen of adhesion of the placenta to the head of a foetus deformed by urania.\nFig. 595.\nEctopia cordis and adhesion of the Placenta.\nIn fig. 596. a pseudo-membrane passes to","page":943},{"file":"p0944.txt","language":"en","ocr_en":"944\nTERATOLOGY.\nthe forehead, round which is twisted the umbilical cord.\nFig. 596.\nIn some, but very rare, cases, the coats of the ovum are destroyed, and the foetus is immediately attached to the inner surface of the uterus ( Steinmetz). It is not to be denied, that through these pseudo-membranes some malformations of the foetus may be occasioned, as Montgomery has proved,such as the truncation of the extremities, which he names self-ampu-tation. Further than this, however, we may not go, for the brides placentaires of Professor St. Hilaire are certainly not a universal cause of monstrosity. They are too accidental and unstable to be such. The existence of malformations in eggs which Geoffroy St. Hilaire coated over with varnish or wax, affords no proof of the possibility of a mechanical origin of monstrosities. The exclusion of the air prevents, in such a case, the necessary material change in the ovum, in consequence of which the perfect developement of the foetus is impaired.\nThe morbid state of the coats of the ovum may likewise cause the so-called mol\u0153, which, according to their consistency, are divided into mol\u0153 fungos\u0153, carnos\u00e6, cruentce, and tendinos\u0153. Valentin* distinguishes in the sanguineous mass of mola carnosa a net of vessels, from which the blood issues. It is the vascular net of the chorion, in which the mass of blood has been collected, in consequence of too great a supply from the uterus. By these means the villi are distended and removed. The ovum being thus degenerated, occasions defective respiration and nutrition of the foetus, which in consequence soon dies. The ovum, however, may still continue to grow, and is finally expelled. In this manner these mol\u0153 are frequently the cause of miscarriage.\n* Repert. Anat. u. Physiol., Berlin, 1837, B. i. S. 127.\nKerckring* inveighed in a spirited and ingenious manner against the strange accounts which were formerly given of these mol\u0153.\nTo the diseases of the placenta are referred enlargement (Kyll, Pierrard, Devilliers), congestion and apoplexy (J. Clarke, Darigan), calcareous concretions (Hannover). For the aetiology of malformations, this pathological anatomy of the placenta is, however, very unproductive. None of these can be explained by it, nor were any accompanied by these placental diseases.\nNor does the nosology of the foetus afford us much more information, notwithstanding the monograph given by J. Gmesser.f It cannot, however, be denied, that some of its diseases may give rise to deformities ; for instance, chronic inflammation of the brain to hydrops ventriculorum cerebri, and this again to Acrania.\nPerhaps also, as Rokitansky states, a morbid condition of the valves may be the cause of some congenital abnormities of the heart. Yet, notwithstanding all this, the diseases of the f\u0153tus can only, in a very limited sense, be assigned as the cause of its malformation ; and hence the opinion of Otto, who ascribes to this source a great many malformations, ought to be rejected.\n4. A fourth, and assuredly very general, cause of malformation, consists in impeded developement of the f\u0153tus by some remote and unknown cause. It is matter of dispute whether this deforming cause operates on the f\u0153tus in its totality, or whether it affects originally only one system, which spreads its deforming influence over all the others This last idea was embraced by Tiedemann, who at first deduced all monstrosities from some defect of the vascular, and later from the nervous system. In opposition to this hypothesis, I suggest the following considerations.\na. It is opposed to anatomical evidence. The cyclopia, whose nature consists in a more or less simplified eye and a displaced or absent external nose, is attributed by Tiedemann to the original absence of olfactory nerves, producing the deformation of the nasal cavity, and the original fusion of the optic nerves, and of the thalami nervorum opticorum effecting the simplification of the eye. I have found, however, in Cyclopes, more than once, olfactory nerves, and have likewise seen that there was no constant concurrence between the simplified form of the eye and of the optic nerve. A double optic nerve may be found with a single eve-ball (Eller, Henermann). With complete duplication of the internal parts of the eye, and even with two separate eyes, I found a single optic nerve, and likewise a double, though not complete, as well as a single eye-ball, notwithstanding the entire absence of the optic nerve. Similar facts are quoted by Haller and G. F. Wolff! Hare-lip with cleft\n* Specil. Anat. Amstelodami, 1670, Observ. 38 et 95.\nf Die Krankheiten des Foetus. Breslau, 1827. 8vo","page":944},{"file":"p0945.txt","language":"en","ocr_en":"TERATOLOGY.\t945\npalate is attributed by Tiedemann to the original absence of olfactory nerves. G. Vrolik found them, however, in children with hare-lip. The nerves of organs may exist, although the organs themselves may be ab-sent (Seiler, W. Yrolik); and inversely, the nerves may be wanting, while the organs are present (C. G. Buttner). In anencephali the body is very massive, notwithstanding the imperfect condition of the nervous centres. In double monsters there is no definite correspondence between the condition of the nervous system and the duplication of the body (W. Yrolik).*\nb. Embryogenesis teaches that the formation of the several parts of the body is not essentially the result of that of the nervous system, but that, on the contrary, each part is formed and developed independently. I refer to what I have already said, in 1836 (in my treatise on Cyclopia), and am happy to find J. Muller, Rathke, Bischoff, Burdach, and Stannius, with me on this subject.\nWhat is now proved for the nervous system, may equally be applied to the system of bloodvessels; and hence I presume to conclude, that no malformation whatever proceeds from a central system, but is occasioned merely by impeded developement, the cause of which remains concealed. This impediment may be confined to one part, or may be extended over more. This extension may sometimes stand either in causal connexion with an original malformation, as for instance the displacing of the nose in cyclopes ; or may take place in an entirely independent manner. In the latter case, it is a complication of malformation, which proves that it may extend itself to more than one region of the body, and to more than one apparatus. I have met with an instance of this, in which to acrania, cyclopia, and absence of the lower jaw, was added ectopia of the intestines. If the origin of the malformation is derived from impeded developement, the so-called monstra per defectuvi are the result, and from excessive formation arise the vionstra per excessum.\nThe malformations occasioned by impeded developement may, for the most part, be compared with the natural forms through which the foetus passes in its normal developement. On this is founded the ingenious idea of Meckel, previously suggested by Wolff, that most malformations are caused by arrest of developement (bildungshemmung), for which reason they must be said, according to Bischoff, to be formed through arrested developement (liemmungsbildungen). They, however, never give us a perfect representation of the form at which the foetus has been arrested in its developement, because the increased growth and the progressive nutrition of the foetus cannot but make an important\n* On this subject I have given copious elucidation in the Treatise on Cyclopia in Transactions of the First Class of the Koyal Netherland Institute, 1836, voL v. p. 25. ; on Double Monsters, ibid. 1840, vol. ix. ; and Handbuch, vol. i. 1840.\nVOL. IV,\nmodification therein. As the transient forms of the human foetus are for the most part comparable to the persistent forms of the lower animals, the malformations occasioned by impeded developement often acquire a brute appearance ; and thus a reason is at the same time given why they exhibit, in different animals, the form of the lower, but not of the higher classes.\nA consequence of this mode of origin is, that they never deviate so much from the normal form as would exclude them from the rank of organized beings ; and that the deviations from the natural form are confined within definite limits, so that they always reremind us more or less of the regular form. Fixed laws of organization prevail in them, by which they exhibit a certain fitness of organization, and a tendency to render the capacity for life as great as possible, notwithstanding the malformation. Peculiar vital relations are hereby produced adapting them for uterine life, and many are brought forth well nourished and at full time. Most, however, are unfit for life after birth, though for very different reasons.\nThe following remarks may serve for the elucidation of these peculiar vital accommodations : \u2014\n1.\tWe never see in malformed births, dissimilar parts fused or united with each other, such as the intestinal tube with the aorta, the arteries with the nerves, &c. Each part, therefore, retains, to a certain degree, its own independence, according to what Fleischmann denominates lex proprietors. The gullet sometimes coalesces with the larynx, and the bladder with the rectum ; but these parts are not originally dissimilar, being developed from a common mass.\n2.\tThe malformed parts are restricted to their determinate place, according to what Fleischmann denominates lex topicorum.\n3.\tNo malformed organ loses entirely its own character, and no malformed animal loses its generic distinction. It is, therefore, justly observed by Soemmering, that nature does not deviate ad infinitum, and that even in monstrosities a distinct gradation and natural order are observable.\nAn immediate consequence of this must be, that in one and the same sort of monstrosity, there are different degrees of malformation, varying from the greatest possible degree to the very least. We might thus consider the different monstrosities as so many genera, and their varieties as so many species, whereby, according to J. T. Meckel, a new organic kingdom is constituted, differing only from the others by less constancy of form. Consequently a definite type prevails in the generation of monstrosities, and they are subjected to fixed organic laws. This order appears even\u20141. In the number in which they occur within a certain space of time. In 3000 births in Paris, there occurs about one monster (J. Geoffroy St. Hilaire). 2. In the sex. In impeded developement, the malformed children are more frequently female,'\n3 P","page":945},{"file":"p0946.txt","language":"en","ocr_en":"946\nTERATOLOGY.\nin some sorts of double monsters, male. 3. In a definite proportion between the species of the animals, and the most frequent monstrosities in them. Cyclopes, for instance, especially with a snout,occur most frequently in swine ; double monsters in man. 4. In the constant fonti of monsters, even amongst the most hetei'oge-neous animals. Cyclopia, double monsters, acrania, have in Birds precisely the same characters as in the Mammalia. 5. In the greater predisposition to monstrosity among some animals. This is greater among domestic than among wild animals ; greater among the more perfect, than among the less perfect ; three-fourths of the monstrosities occur among Mammalia, one-fourth among Birds (J. Geoffroy St. Hilaire). They happen seldom among Reptilia, still less frequently among Fishes, Mollusca, Articulata, and Radiata.\nFrom these premises the consequence is easily derived, that monstrosities do not take place by chance, and therefore do not by any means deserve the so very general appellation of caprices of nature (lusus natures). The result of this is, that they often present a quantitative antithesis, according to what Geoffroy St. Hilaire denominates loi de balancement. According to this law, the excessive developement of one part of the body is often connected with checked formation of another. To anencephalia, cyclopia, spina bifida, are often joined fingers and toes in excessive number ; to sireno-melia superfluous vertebrae and ribs ; and frequently there occur in double monsters malformations of the head. Meckel saw, in one single instance, this antithesis extend itself over different children of one and the same mother. A girl had on each extremity a superfluous digit, and one hand of her sister wanted four fingers, being the number of digits which her sister had in excess, reckoning the four extremities together.\nI have now arrived to the classification of monstrosities ; but in order to prevent all unnecessary waste of time, I shall avoid entering into a full critical examination of the systems propounded by Licetus, Huber, Wigtel, Malacarne, Buffon,Blumenbach, Bres-chet, Geoffroy St. Hilaire, Gurlt, Otto, and Bischoff. Concerning these I refer to Bis-choff*, from whom Rokitansky has chiefly borrowed what he gives in his manual. According to my conviction, no suitable classification of monstrosities can be given, and the efforts employed to this end may be regarded as failures. I confine myself, therefore, to a simple grouping, taking embryogenesis as my basis, without presuming on any further classification, and I thus avoid a barbarous nomenclature, which, in my opinion, is attended with no advantage. My object is simply to make the doctrine of malformations useful for physiology and for medical practice, nearly in the same manner as was done, almost\n* Entwickelungs Geschichte mit besondere Ber\u00fccksichtigung der Missbildungen, in R. Wagner Handw\u00f6rterbuch d. Physiologie, B. i. S. 887.\nsimultaneously with me, by the excellent F. A. von Ammon.*\nMalformations of the Ovum.\n1.\tMola botryoides or hydatica, \u2014 Hydrometra aquatica,\u2014is a degeneration of the chorion into vesicles of different sizes, filled with a serous liquor, which were erroneously taken for hydatids. They cover the surface of the enlarged ovum, and are the villi of the chorion, which, as no formation of vessels took place, retained their original vesicular form (Ruysch, Albinus, Sandifort, Cruveilhier, Velpeau). Sometimes a foetus is found in it, which, however, in relation to the ovum may be said to be small.\nThe small embryo most probably dies in the early period of pregnancy, and the degenerated ovum continues to grow till a later period, when it is evacuated. In most cases abortion is the consequence of this condition of the ovum. Sometimes, nevertheless, the pregnancy lasts till the full time (Gregorini), or sometimes longer, as happened in a case observed by Lossins, in which it lasted six years. Sometimes the f\u0153tus disappears, and then this degenerated vesicular mass is evacuated alone, with excessive haemorrhage and great pain. This is the last period of what is called false pregnancy.\nThe vesicles are inclosed in a kind of decidua ; they are fixed on pedicles, from which arise other vesicles with smaller stems, so as to give to the whole the appearance of the chorion, in an earlier period of its existence, when the villi still preserve their original vesicular form. The accurate observations of Boeck show that, in most cases, these vesicles contain blood, which sometimes can be displaced by pressure from the one to the other vesicle, or is coagulated. The internal surface of the membrane which forms the vesicle is smooth, the external interwoven with fibres. A thus degenerated ovum has not the power of bringing the f\u0153tus to a state of perfect maturity. The death of the f\u0153tus and miscarriage are its consequences. Sometimes the Mola botryoides is accompanied by malformation of the f\u0153tus (Valisnieri).\nFrom this degeneration ought to be distinguished : 1st. The vesicular degeneration of the placenta, when retained after a natural parturition in the womb (Gregorini) ; 2nd. The Polypi fugaces or vesiculares evacuated in the anni climacterici by elderly women (Lev-ret) ; 3rd. Those after suppressed menstruation in unpregnant women (Schleierbach, Watson, Sporing, Lisfranc). As I have no observations of my own of any of these cases, 1 dare not pronounce any opinion about the affinity of these vesicles to the Mola botryoides.\n2.\tSeparation of the placenta into lobes or cotyledons. \u2014 This is without doubt to be attributed to an arrest at a lower degree of developement, and it offers some resemblance\n* Die angeborenen Chirurgischen Krankheiten des Menschen. Berlin, 1842.","page":946},{"file":"p0947.txt","language":"en","ocr_en":"I\nTERATOLOGY.\t947\nto the placenta of the Ruminants. The smallest amount of deviation is a division into two coherent lobes, which are separated only by a small constriction (J. F. Meckel, Ebert). Such a placenta has an oblong form. Sometimes there is a single lobe adjoined to the placenta (placenta succenturiata) ; it is of much smaller dimensions than the placenta itself, and united to it by vessels, without a cord. The placenta may also be divided into three (Rohault, Schwencke), four (Hoboken), five (Meckel), or seven lobes (Kerckring, Wrisberg). In the observation of Kerckring, the arrest at a lower stage of development is clearly shown by the presence of the Vena omphalo-mesenterica.\n3.\tThe vessels of the umbilical cord are separated near the placenta, and meet at a considerable distance from it (Sandifort, Wrisberg, Adolph). In one of the published cases, this disposition of the vessels was the cause of their rupture, which produced the child\u2019s death by haemorrhage. Sometimes they were observed to run separately from the placenta to\nFig. 597.\nMalformed F\u0153tus, showing the cord entwined around the neck and part of the body.\nthe abdomen of the foetus, into which they penetrated through separate openings. In most cases they meet each other just at the umbilicus (Gavel, Van Solingen).\n4.\tThe umbilical cord too long. \u2014 The common length of the cord is twenty inches (Roederer, Wrisberg), but it may be forty-eight inches (Wrisberg), sometimes even five feet (Morlanne). The usual effect of such an abnormal length of the cord is a circumvolution of it round the body of the foetus. An example of it is given in a very misformed foetus in fig. 597.\nA cii\u2019cumvolution of this kind may sometimes become dangerous : 1. By acting as a ligature round the neck, and producing strangulation of the foetus (Buchanan, Hebenstreit) ;\n2.\tBy constricting one of the extremities, and producing the spontaneous amputation ot Montgomei'y (Art. F\u0153tus,fig. 157. Vol. II.)\n3.\tBy forming single or compound knots. Although these are in general not dangerous, while the vessels are sufficiently pi'otected against pressure by the Whartonian gelatine, they may nevertheless in some cases be drawn so tight as to obstruct the communication between mother and child (Sandifort, Irvets, D. W. H. Busch) ; and sometimes the umbilical cord breaks off near the knot when the vessels have become obliterated by the pressure. Fig. 598. gives an example of this in an acephalus.\nFig. 598.\n5.\tThe umbilical cord too short. \u2014 Wrisberg gives as a minimum a measure of seven inches. It may, however, be much less. This shortness of the cord is in general accompanied by a deformity of the foetus, usually by ectopip of the abdominal viscera, by wThich it indi-dicates an arrest of developement at an earlier period of embryogenesis. In this way we should interpret the accounts of absence of the umbilical cord.\n6.\tAbsence of one of the umbilical artenes, is even observed in double monsters, but occurs principally in ectopia viscerum abdomi-\n3 p 2","page":947},{"file":"p0948.txt","language":"en","ocr_en":"948\tTERATOLOGY.\nnalium, and in defective formation of the inferior part of the body. Serres hence derived the conclusion, that this malformation is the consequence of the want of one of the umbilical arteries ; which is however wrong, as the evolution of the whole body may be complete, even when one of the umbilical arteries is wanting. Fig. 599. represents a specimen of this kind.\nFig. 599.\na, aorta ; b, b, spermatic arteries ; c, superior mesenteric ; d, d, common iliacs ; e, the single umbilical artery ; f, vena cava.\nMende even observed in a very well formed child absence of one of the umbilical arteries, together with an unusual course of the umbilical vein, which, instead of communicating with the vena port\u00e6, opened immediately into the right auricle of the heart.\n7.\tIncreased number of the vessels of the cord. \u2014 A double umbilical vein is constantly to be found in the Quadrumana of the New World (Rudolphi). In Man the unusual plurality of the umbilical vessels is but apparent, as it is produced by the persistence of the vasa omphalo-mesenterica.\n8.\tPersistence of the umbilical vesicle, is a natural condition in the Ouistiti (Rudolphi), and occurs as a deviation in Man. Sometimes it is only its duct that remains united with the small intestine, forming what we call a diverticulum.\n9.\tConstriction of the umbilical cord occurs at the point where the cord penetrates into the abdomen. In the constricted part the vessels, although remarkably narrowed, still allow in some measure the circulation of the blood. The cord is thereby contorted into a spiral. The death of the foetus is its usual effect (Landsberger). Fig. 147. of the second volume of this Cyclopaedia gives a represent\u00ab ation of this constriction of the umbilical cord.\n10.\tThe umbilical cord too thick. \u2014 Its diameter varies from 1*\u20142| inches. This is, in general, the consequence of an uncommon accumulation of the Whartonian gelatine, or of an cedematous conditon. In one of the\nrecorded cases, the superior extremities were wanting, and the anus was closed. In other cases it is occasioned by an enormous quantity of the liquor amnii, which is usually accompanied with an abnormal developement or impeded growth of the foetus.\nMalformations of the F\u0153tus.\nIt is impossible to give in a concise article, such as is suited to a cyclopaedia, a complete description of all the various malformations of the foetus. I must refer to my manual, published in Dutch, under the title De mens-chelyke Vrucht beschouwd in hare regelmatige en onregelmatige ontwikkeling, Amsterdam, 1840 en 1842, and to my Tabulce ad illustran-dam Embryo -genesin Hominis et Mammalium, where a more full and accurate description of the various kinds of malformations of the foetus is to be found. I can give here only a short description of the principal groups, as an introduction to the doctrine of the malformations of the foetus.\nA. Monstrosities produced by an Arrest of Developement.\nI. Non-closure of the anterior Part of the Body.\nEmbryogenesis teaches us, that the thoracic and abdominal cavities are originally open, and close themselves by degrees at a later period of uterine life. The late ossification of the sternum and of the pubic bones is the result of this original disposition. The points of ossification are not formed in the broad cartilaginous basis of the sternum before the fourth or fifth month of pregnancy ; they are in the beginning widely separated from each other by broad intervals in the middle, and approach later to fuse into one central osseous piece. This mode of formation explains some of the original malformations of the sternum; namely, its abnormal breadth, the openings which are found in it, and its separation into two parts. These two last conditions denote, that the sternum is the compound of two lateral halves fused together (Rathke). The separation of the sternum into two parts usually accompanies ectopia of the thoracic and abdominal viscera.\nSometimes, although the thoracic viscera are enclosed in their cavity, the original division of the sternum remains, and is covered up by the skin (Ficker, Serres, Winslow). In some rare cases, the whole or the largest part of the sternum is absent in individuals with no other deformity (Yon Ammon). In most of these cases the manubrium alone is present (Wiedemann). In some, but very rare, cases the anterior wall of the thoracic and abdominal cavity is only closed by the skin, and its osseous and fleshy parts are completely deficient (R. G. Mayne). The linea alba is, as well as the sternum, the cicatrix of a cleft existing at an earlier period. This explains its abnormal breadth, obvious in those cases in which the wall of the abdomen has been","page":948},{"file":"p0949.txt","language":"en","ocr_en":"TERATOLOGY.\t9+9\nclosed at a later period than usual. An example of it is given in my Tabula XXIV. fig. 4. Sometimes the muscles of the anterior abdominal wall are wanting, in which case the convolutions of the intestines may be seen and felt through the skin (Von Ammon). The thoracic and abdominal cavities being open in the first periods of embryogenesis, if this condition persists abnormally, it produces ectopia of the thoracic and abdominal viscera. The aperture through which the ectopia takes place has a constant tendency to close; it shrinks therefore sometimes to a very small opening (Hammer). Sometimes it is closed in the middle, by a band which separates the uncovered viscera into two portions (H\u00fchner,\nWolff).\nIts principal forms are : \u2014\n1. Fissure of the whole anterior Wall of the Body.\na. Complete ectopia of the thoracic and abdominal viscera, which lie bare upon the anterior surface of the body, to which is generally added a cloaca. (Fig. 600.)\nFig. 600.\nChild with ectopia viscerum.\na, liver ; b, heart ; c, c, lung ; d, stomach ; e, spleen ; /,/, intestinal canal ; g, kidney ; h, chorion ; i, amnion ; k, umbilical cord ; m, placenta.\nThe skeleton is very imperfect, in this complete ectopia ; the thorax open, and the vertebral column misformed by scoliosis.\u2014 This may produce, as often met with in calves, a complete inversion of the body, so that through distortion of the spine, the head is\nplaced between the hind feet. This is what Gurlt calls schistozomus refiexus, and what I represent in fig. 601.\nFig. 601.\nSchistozomus refiexus (Gurlt).\n2. Fissure of the Thorax.\nEctopia of the heart. \u2014 In the regular evolution of the foetus, the opening on the anterior wall of the body closes itself, first at its superior part, so as to cover the thoracic viscera, while a part of the abdominal intestines still remain out of their cavity and in the sheath of the umbilical cord. Thus the thoracic cavity is in general already closed, whilst the abdominal is yet open. Nevertheless, it sometimes happens that the abdominal cavity is completed, and that its viscera are perfectly enclosed, whilst the thorax remains open, and the heart is placed on its anterior surface. In this malformation, called ectopia cordis, the heart has no pericardium, and is situated on the median line of the anterior wall of the thorax ; it is more or less rounded, and in general well formed, as may be seen in fig. 595. The sternum is wanting (Tournelle, Norand, Sandifort) ; divided into two parts (Buttner, Martinez) ; or formed only by the manubrium (Manchardt). It is rarely complete ; but this is often the case when the heart protrudes at the neck (Muse, Bubon-nais, Breschet), or in the epigastric region (Wilson).\nDuring foetal life, the ectopia of the heart is immaterial, but soon after birth it causes the death of the child* Cruveilhier published some interesting observations on the movements of the heart in a case in which life was protracted for a longer time than usual.*\n* British and Foreign Review, No. XXVI. October, 1841, p. 533.\n3 p 3","page":949},{"file":"p0950.txt","language":"en","ocr_en":"950\tTERATOLOGY.\n3. Fissure of the anterior abdominal Wall.\na.\tComplete ectopia of the abdominal viscera. \u2014The abdominal cavity is in general the last closed. When it alone remains open, the abdominal viscera only lie out of the body. The fissure is mostly extended from the ensi-form process of the sternum to the pubic bones. One of the umbilical arteries is in general wanting. Commonly this malformation is complicated with adhesion of the membranes of the ovum or of the placenta to the divided integuments of the abdomen, with a cloaca, with defective generative or uropoietic organs, and with an incomplete pubic articulation.\nb.\tCongenital umbilical hernia. \u2014 In a less degree of deformity, the fissure is limited to the epigastric region, above the insertion of the umbilical cord, because this part of the abdomen remains longest open. This gives origin to congenital umbilical hernia. \u2014 The umbilical cord passes under the viscera, which lie exposed, or are only covered by the peritoneum. In the last case a sort of hernial sac is formed, which has a cylindrical or globular form, and is produced by the two coats of the ovum.\nThe external coat is that part of the amnion which is the covering of the umbilical cord ; the internal, the peritoneum, which is considered by Meckel as a continuation of the chorion from the umbilical cord. All these facts prove that congenital umbilical hernia is caused by an arrest of developement at that stage, in which a part of the abdominal viscera are contained in the sheath of the umbilical cord. The size of the tumor is variously modified by the number and by the volume of the viscera contained in it. When it contains the liver, it is of a bluish colour. The viscera lying in it, are always in an imperfect condition. Only four cases are known, in which the life of the malformed child lasted for any time after birth (Meckel, Cruveilhier, Ribke, Van der Voort) ; in the case of Van der Voort for eight, in that of Ribke for twelve months. In all these cases the external coat of the hernial sac has mortified, and the tumor has become gradually covered by the skin. An accurate diagnosis of this malformation is of great value. In two cases, in which it was rot accurately recognised, a ligature was put round the tumor, and it was cut off. One of these cases was the subject of an interesting law proceeding.\nc.\tCongenital ventral hernia. \u2014 The abdominal cavity may also remain open, below the umbilical cord (Fried, Hasenest, Bouchard). This produces congenital ventral hernia. The viscera lie exposed, or are covered by the peritoneum.\nd.\tAcquired umbilical hernia. \u2014 Hernia in the umbilical cicatrix ought to be distinguished from all these forms of ectopia. It is not a congenital deformity, but is produced after birth by an expansion of the umbilical cicatrix to a globular, a cylindrical, or a conical tumor. It is often observed in adults. If we adopt for these the name of acquired, and for those\nof new-born children that of congenital hernia, it would be better to give to the true congenital umbilical hernia the name of hernia funiculi umbilicalis (Seiler).\n4. Fissure of the pubic and hypogastric Regions.\nIt sometimes happens that the pubic region alone remains open. For a correct idea of the malformations produced by it, it should be borne in mind that in the Mammalia, and, as recent observations teach, also in Man (Bischoff, Wagner, A. Thompson, Coste, Sevres, Arnold), the urinary bladder is formed by the allantois. This is originally in communication with the inferior part of the intestinal canal, so as to form for both a common outlet, called a cloaca, from which are evolved at a later period the peripheral openings of the intestinal tube, and of the uropoietic and generative organs. The pubic bones are formed later than the iliac (Meckel) and the previously existing ischiatic bones. Their formation proceeds from the outside to the inside ; therefore they are at first separated from each other by a large interval, and subsequently approach each other, in a gradual manner, for the z formation of an amphiarthrosis. The f\u0153tus may be arrested at this period of incomplete pubic articulation. In an observation of Walter, there was a fissure in the pubic region, though the genital and uropoietic organs were not malformed. This is the normal condition of some mammalia, and of the majority of birds.\nAn arrest of developement may also take place at the period when there exists a fusion between the rectum and the allantois. Of this various forms occur.\na. Formation of a cloaca.\u2014 A cloaca is said to ' exist, when the generative and urinary organs and the rectum have a common outlet. This is often complicated with ectopia of the thoracic and abdominal viscera. The cloaca may also exist alone. In its highest degree, the ureters, the imperfect organs of generation, and the opening of the rectum, are situated close to each other in a circular depression (Petit). In other cases, which approach more to the natural condition, there is a primordial urinary bladder, formed of two separate parts (Mery), or merely constituted by its bare posterior wall. Fig. 602. shows how the fissured urinary bladder may be complicated with the formation of a cloaca.\nIn most of the cases which I have published, the opening through which the faeces are evacuated, is formed by the ileum, and the rectum is closed or wanting. This confirms the original formation of the intestinal tube by a mouth- and anus-gut. In a case mentioned by Jung these two portions are quite separate, and have each its separate opening on the prolapsed posterior wall of the urinary bladder. When these two openings are fused, the cloaca persists, but approaches more to the natural condition. This may take place in different ways :\u2014 1. The orifices of the ureters only may be found on the posterior wall of the bladder, or in the so-called inverted bladder, while the rectum still coheres","page":950},{"file":"p0951.txt","language":"en","ocr_en":"TERATOLOGY.\nwith the genital organs, just as in the cases of imperforate anus just mentioned (Meckel, Burns), or with an open anus, as in the cases of Zhryham, Oliver, and Bonnet ; this condition approaches the nearest to the natural state,\nFig. 602.\nHypogastric region of a Child, which lived tioenty-two days, with vesica inversa, fyc.\na, a, congenital umbilical hernia ; h, umbilical cord ; c, c, the separated halves of the vesica urinaria, with the urethral orifices ; d, anus ; e, e, penis epi-spadiacus ; f. frenulum ; g, cutaneous appendage to the closed anus.\nif the urinary bladder is complete (Martin) ; 2. The rectum maybe separate, while the urinary bladder remains fissured and fused with the genital organs (Meckel, Gross); 3. The fissured urinary bladder may be separated from the anus, without taking up the ureters, which then open themselves into the rectum (Meckel, Oberteuffer). In some cases the outlets of these three apparatus are found not on a flat surface, but in a cavity. The cloaca, existing previously on the surface of the body, is then removed from it and folded in, so as to form a cavity.\nIn another degree of malformation the cavity is formed, and the uropoietic and generative organs are completely separated from each other ; but the rectum, being a distinct oijan, is nevertheless in connection with one of the said parts, by means of a sort of canal. In the female sex this communication is found between the rectum and vagina (fistula ani vaginalis congenita) ; in the male sex between the rectum and urinary bladder ^ (fistula ani vesicalis congenita). The transition towards the natural state is nearest when the rectum opens into the urethra ; to this condition, when it is complicated with an imperforate anus, Papendorp has given the name of atresia ani urethralis.\nb. Congenital fissure of the urinary bladder.\u2014 Without a cloaca, and with a perforate anus, the interior surface of the posterior part of the bladder may lie exposed on the hypogastric region (prolapsus, inversio, fissio vesic\u00e6).\n951\nIt then forms a red, spongy tumor, situated somewhat above the separated pubic bones, and involving the umbilicus, so as to give the appearance of a deficiency of the umbilical cicatrix. In male children the orifices of the vasa deferentia are to be found on the inferior part of the tumor. The urethral orifices are papillary eminences on the naked internal surface of the bladder. The urine drops continually out of them, but may sometimes be seen to issue in a small stream. The pubic bones are widely apart, sometimes with an interspace of four inches. They have no intermediate cartilage, but are merely united together by a ligament, without forming a synchondrosis. The consequence of this is a very peculiar reeling in the walk of the malformed subject, and a great disposition to inguinal hernia, due to the absence of sufficient support at the interior surface of the body. The penis is fissured on its superior surface (epispadias). The testes are, even in adults, very small, and often retained in the abdomen or in the inguinal canals. The seminal vesicles, the prostate and the vasa deferentia, offer various deviations. In the female sex the labia majora and minora are separated and without a commissure at their upper part. The vagina is often closed or very narrow. The anus is more protruded than in the natural condition.\nSometimes the penis is epispadiac, with a well-formed urinary bladder. In such a case, Bonn found, nevertheless, the pubic bones apart, but united by a ligamentous texture. Although the continual dropping of the urine is a very annoying disturbance, which I contrived to remove by the means illustrated in figs. 603 and 604 , and although the generative organs are very incomplete, this malformation is not dangerous to life, which in several cases has been remarkably protracted.\nFig. 603.\nHypogastric Region of a lining Child, with vesica inversa.\na, internal surface of the urinary bladder ; b, umbilical cicatrix ; c, c, urethral orifices ; d, epispa* diac penis ; f, e, scrotum.\n3 p 4","page":951},{"file":"p0952.txt","language":"en","ocr_en":"952\tTERATOLOGY.\nFig. 604.\nThe same Region armed with an Apparatus for the reception and evacuation of Urine.\nc. Ectopia vesic\u00e6 urinari\u0153. \u2014 The smallest degree of deformity is when the urinary bladder remains intact, but lies in an opening in the wall of the hypogastric region. It is ectopia vesic\u00e6 urinari\u0153, of which a representation is given in fig. 605.; and for more details I refer to my \u201c Tabulae ad illustrandum embryo-genesin,\"\u2019 etc., Tab. xxx.\nFig. 605.\nHypogastric Region of a Child, which lived six years, with ectopia vesic\u00e6 urinari\u0153.\na, part of the bladder lying on the surface of the abdomen ; b, umbilical cicatrix ; c, penis ; d, d, prepuce ; h, urethral orifice ; f scrotum ; g, g, testes, lying at the inguinal region.\nd. Inversio vesic\u00e6 uninari\u00e6. Prolapsus vesic\u00e6 urinari\u0153 invers\u00e6. \u2014 If the urachus remains open after birth, the urinary bladder may be expelled, and thereby inverted through it. R. Frorlep (Chirurg. Kupfertafeln, Heft 67. Taf. cccxl.) has given an example of this malformation. It ought to be distinguished from the inversion of the bladder through the urethra, which is possible even in adult women (Voigtei).\nIf we take a general survey of all these cases of non-closure of the hypogastric region, it\nis evident that they are intimately connected with one another.\nThe cloacal disposition is the highest, the ectopia of the urinary bladder the lowest, degree of malformation, and therefore the latter is a distinct transition towards the natural condition. The inversion of the urinary bladder observed by Froriep has, as to its origin, no direct relation to the other forms. It is but an accidental effect of the remaining open of the urachus, through which the bladder chanced to become inverted, and the urine flowed away through the urethra if the child was held upright. From the gradual transition of one form into the other, I conclude that the origin of this malformation cannot well be attributed to a mechanical cause, as Duncan and Bonn have asserted nearly at the same time. They both consider it the effect of a preternatural accumulation of urine, causing a violent distension, and later a rupture of the bladder, of the urethra, of the hypogastric region, and of the pubic articulation. This theory had already, in the year 1816, a very strong opponent in my father (Verh. d. Ie kl. van het Koninkl. Nederl. Instit. D. II. B. 88). His chief arguments against it, to which I add my own, are :\n1. That, if the urinary bladder bursts, as may happen in adults, the urine will be evacuated into the abdominal cavity, without Assuring the anterior wall. 2. That it is improbable that in some cases such an accumulation should fissure the whole apparatus, and in others restrict its effect to the corpora cavernosa, penis, and the urethra, as may be seen in simple epispadias (W. Vrolik, Bosson, Sals-mann, Morgagni, and Oberteuffer). 3. That by an observation of Baillie is proved, that in fissure of the urinary bladder the posterior part of the urethra may remain intact and closed, while the corpora cavernosa are fissured at the anterior part of the penis. 4. That I have often found in the foetus atresia urethr\u00e6 complicated with an unusual expansion of the urinary bladder and of the ureters, but without the least sign of bursting or of producing the malformation in question. 5. That ectopia of the urinary bladder demonstrates that the anterior wall of the abdomen may be open, the urinary bladder remaining intact ; or the supposed effect may exist, when the cause is absent. From all these and other remarks and observations I conclude that the origin of this malformation is not to be found in a mechanical cause, neither internal nor external (Roose). I am much more inclined to ascribe all its different forms to arrest of develope-ment. My chief grounds for this opinion are the frequent coexistence of:\u2014 1. The want of arter\u00ef\u0153 hypogastric\u0153 (G. Vrolik); 2. Abnormal condition of the kidneys and the ureters (Pinel, Cooper, Isenflamm); 3. Fissured dorsal vertebrae (Littr\u00e9, Revolat, Delfin, G. Vrolik) ; and many other malformations, as labium leporinum (Dupuytren, Meckel), confluent toes (Saxtorph). The only question which remains is, what is the cause of this imperfect developement ? As to the cloacal","page":952},{"file":"p0953.txt","language":"en","ocr_en":"TERATOLOGY.\t953\nformation, it is certain that it may be said to be an arrest at an earlier period of evolution ; but this is not certain with regard to the vesica fissa. The origin of this can only be explained by an imperfect developement of the urinary bladder from the allantois. It is not improbable, as my drawing of the cloacal formation shows also, that the urinary bladder is formed by two half-parts, which approach each other anteriorly and posteriorly on the mesial line. If this junction does not occur, the different forms of vesica inversa will be formed. Atresia ani is, in the cloacal disposition, without doubt, an arrest of developement at an early period of embryoge-nesis ; for previously the anus is closed. And epispadias shows that the penis is formed by two parts, which may remain separated from each other on the superior surface. Consequently it appears, that the name of vesica inversa is as improper as that of vesica fissa. But I shall propose no other name, because we know sufficiently the meaning of it.\n5. Cervical Fissure (Fistula colli congenita).\nRecent observations teach us that the original branchial fissures may persist in the neck even in adults. Hyrtl mentioned this malformation in a man of twenty, in whom the external cervical opening was small and communicated with the pharynx close to the epiglottis. Among 34,000 young men, Riecke found a fistula colli congenita twice.\n6. Fissure of the Face.\nIn order to obtain a correct notion of the different forms under which fissure of the face may occur, it will be necessary to know the gradual metamorphoses of the face during its developement. Originally there is a common oral and nasal cavity. The place of the nose is occupied by two fissures, which extend from the internal angles of the eyes to the superior margin of the oral cavity. There is at this period not the least indication of a palate, so that the mouth and the nose form one common cavity. In a human foetus of less than an inch in length, Meckel found the first rudiment of a palate, in the form of an arc or a horse-shoe shape. On each side this arc is gradually completed, so as to be at first open at its posterior part, but closed afterwards, and forming a complete transverse plate, separating the nasal from the oral cavity. Rathke examined this more in detail, in foetuses of the sheep : \u2014\n1.\tHe learned that the supermaxillary cavity is formed on each side from the lateral walls of the cranium.\n2.\tThat between those two parts grows out of the frontal wall of the skull a third eminence, which forms the basis for the septum of the nose, that is, for the formation of the vomer, of the septum of the ethmoid bone, and of the intermaxillary bones.\n3.\tThat the two parts, quoted under No. ]., are bent inwards, and coalesce with the mesial part.\n4.\tThat the nasal cavity is at first a groove,\nand has originally a form which persists through their whole life in fishes.\n5.\tThat the oral and the nasal cavity form originally a common cavity.\n6.\tThat the palate is originally a fissure. By arrest of developement in these different stages of embryogenesis, are formed the different species of facial fissure.\na.\tComplete fissure of the face. \u2014 The highest degree of malformation is, when the fissure is extended from the angle of the mouth to the internal angle of the eye, the orbits, the nose, and the mouth forming but one cavity. J. S. Meckel, Van Doeveren, and myself have published examples of this malformation complicated with acrania. The fissure sometimes extends only over one lateral part of the face (Leuckart), and in the greatest transition to the natural condition it is buta shallow groove, as is represented in fig. 596.\nA fissure sometimes extends in a transverse direction over the head. C. Meyer observed this twice in new-born sheep. In both the palate had a double fissure, and the normal opening of the mouth reached as far as the ear, which in one of these lambs presented a transverse fissure.\nb.\tDouble labium leporinum. \u2014 A transition to the normal condition, yet a very imperfect one, is when the fissure is not extended over the whole surface of the face, but is restricted to the upper jaw. The highest degree of deformity is double hare-lip with fissured palate (Labium leporinum duplex cum potato fisso). On each side of the upper lip a fissure extends from the angles of the mouth to the alee nasi. Between these is a protuberant tubercle, covered by a separate part of the upper lip, and consequently by the external skin and the gums. The tubercle is connected with the septum of the nose, generally obliquely distorted, and is filled up with the germs of the incisors. By the confusion of the oral and nasal cavities, the true nasal orifices are wanting, the osseous palate is defective, the soft palate and the uvula are fissured, and the vomer united anteriorly with the protuberance, hangs in the midst of the fissure. In a lesser degree of malformation, the alveolar margin of the upper jaw is alone fissured, and in the least degree the palate is complete.\nc.\tSingle hare-lip. \u2014 This name is adopted for the malformation when it is limited to one lateral part of the face. It may be complicated with fissured palate. The lip is then, on one side, fissured to the nostril, so as to form there an immediate communication between the oral and nasal cavity. The direction of the fissure is seldom accurately in the mesial line. If this occurs, it is the result of defective intermaxillary bones. The palate offers either a simple or a double fissure. In a less degree of malformation only the alveolar ridge is cleft, and, in the least, the palate is complete. In such a case the fissure of the upper lip is merely a small incision.\nd.\tFissure of the palate without a hare-lip. \u2014 The alveolar margin is in this case quite complete, but the palatine and the supermaxil-","page":953},{"file":"p0954.txt","language":"en","ocr_en":"954\tTERATOLOGY.\nlary bones are largely separated from each other posteriorly, so as to form a fissure, more or less extensive, of the bony and of the soft palate. Sometimes there is only a fissure of the uvula (Yon Ammon). The nearest approach to the natural state is, when the planes of the palatine bones form with each other an acute angle rising high upwards in the nasal cavity (Himly, W. Vrolik). In some cases, the palate is fissured at its anterior part, close to the foramen palatinum anticum (hiatus Jbra-minis palatini antici, Von Ammon). En resume, it appears that fissure of the palate and hare-lip are independent of each other. But it may happen that, originally, the fissure of the palate coexists with the hare-lip and closes itself later. The indentation which is observed in hare-lip without fissure of the palate, Between the external incisive and the canine tooth, makes it probable that nature proceeds in this manner. It is also not improbable that hare-lip may sometimes be cured spontaneously in the womb. The gradual transition of the various forms of this malformation into each other, shows that its cause is not external and accidental, and that it is produced, neither by blows which the child inflicts upon itself with its fists (Jourdain), nor by a mechanical impediment preventing the union of the palatine laminae (Pinnder). Complete fissure of the face and the palate is rather to be considered as an arrest of developement at an early period of formation. Hare-lip conforms with the foetal condition in that period of developement which I have called the third. If the original intermediate protuberance does not unite itself with the lateral parts, double harelip is formed. The protuberance obvious in it is formed by the intermaxillary bone either in its totality, or only by a part of it. If it unites itself with only one lateral part, single hare-lip is formed. The intermaxillary bone is composed of four separate parts, of which each contains an alveolus. The result of this is, that each of these parts may be united, separately, with the supermaxillary bones ; which fact explains clearly why only three or two incisive teeth are sometimes to be found in the protuberance. The fissure of the upper lip sometimes occupies the mesial line, passing through the middle of the intermaxillary bone. This is also the case when the intermaxillary bone is wanting.\nIn this way, all the various forms of fissure of the face can be reduced to an arrest of developement, which explains in the meantime the constant tendency of the fissure to close itself, as may be observed in children having this malformation. Fissure of the palate and lip does not endanger the life of children, and union of the separated parts in hare-lip and cleft palate can be obtained by a surgical operation.\ne. Fissure of the under lip. \u2014 The under lip is very seldom cleft (J. F. Meckel, Von Ammon, Nicati, Bonisson). It is equally rare for the under jaw to remain after birth separated into two parts.\nII. Fissure of the Skull (.Acrania).\nMany forms of this monstrosity are known, to which different names have been given, as acephalia spuria, microcephalia, anencephalia, hemicephalia. But, for its shortness and etymological sense, I prefer the name of acrania, which was introduced by J. F. Meckel. Under this name I comprehend all the different forms in which this malformation occurs, and also, with Himly, the hernia cerebri. According to my opinion, the division into different families and genera, and the nomenclature of J. Geoffroy St. Hilaire, ought to be rejected. I, for my part, am always inclined to simplify science as much as possible, and to be succinct in its exposition; and I propose, therefore, the following types.\nFirst Type. \u2014 Want of the brain, and exposure of the whole basis of the skull. \u2022\u2014 The superior surface of the cranium is flat, and not formed by the bones of the skull, but only by a membrane, of which the margin is very unequal, hard, and formed by bones. The external integuments extend over this margin, and terminate there in an unequal line, which is distinctly circumscribed by the thick hair of the head. With this cutaneous border is connected the slightly vaulted membrane, of a red, somewhat bloody colour, which immediately covers the periosteum that invests the more or less convex surface of the basis of the skull. The brain is wanting, but the central terminations of the cerebral nerves are in most cases present, yet sometimes these also are wanting (J. F. Meckel). The forehead is flat, and directed forwards in an oblique direction. The eyes protrude on its anterior or orbital margin, covered with swollen superior eyelids, and directed more or less upwards. The face is flat, and nearly horizontal ; the upper, and still more so the under jaw are comparatively longer than those of a well-formed subject ; the tongue is in general prominent, because the mouth cannot be shut on account of the\nFig. 606.","page":954},{"file":"p0955.txt","language":"en","ocr_en":"TERATOLOGY.\n955\nlength of the under jaw. These distortions give to such monstrosities a certain brute-like aspect which induced the Germans to call them Katzenkopfe and the French t\u00eates de crapaud. If the cervical part of the spinal column is in the meantime cleft, the cervix is so shortened, that the head seems to be fixed on the shoulders, and the chin rests on the breast, as is represented in fig. 606.\nThe malformation of the bones of the skull and of the face is very great ; but as its description would take too much room here, I refer the reader to my handbook and my plates, and also to fig. 607., which will give a clear idea of it.\nFig. 607.\nSkull of a new born Child with Acrania.\na, a, frontals ; b, nasals ; c, c, very convex zygomatic bones ; d, small ensiform processes ; e, sella turcica al\u00e6 majores ossis sphenoidei; g, g, petrous bones ; h, basal part of the. sphenoid bone ; i, i, condyloid parts of the occipital bone ;\nl,\tl, depressed squamous parts of the occipital bone ;\nm,\tsmall osseous lamin\u00e6, representing the parietal bones.\nSecond Type.\u2014 The denuded surface of the basis cranii occupied by a spongy substance, instead of brain. \u2014 In most cases vesicles, filled with a serous liquor, were observed to occur in this spongy substance, and with these occasionally also medullary corpuscles, which may be considered as rudiments of brain. There is sometimes a rudiment of the cerebellum, together with a rudiment which is continued into the spinal medulla, as though it were a medulla oblongata. The cerebral nerves are sometimes quite separated from, sometimes united with, the spongy substance. Sometimes they have the form of complete or lacerated bags, which extend along the superior surface of the skull and the posterior surface of the spinal column. The spinal co-\nlumn is either perfect, or partially, and sometimes entirely, cleft. The last of these conditions is represented in fig. 608.\njFig. 608.\nTo this form of monstrosity Geoffroy St. Hilaire gives the name of anencephalus. Specimens of it were found amongst the Egyptian mummies in the sacred sepulchres of the Cy-nocephali and Ibis, which is a very interesting fact as regards monstrous births in those times.\nThird Type. \u2014 The surface of the basis cranii only partially denuded, \u2014 a spongy tumour occupying the place of the brain. The skull may be closed at its posterior part, and remain open at its summit. A more or less malformed cerebral substance appears on the summit of the skull, just as if it were\nFig. 609.\nSection of the Head of a Child with Acrania, to shoio the union of the malformed brain with the spinal cord.\na, b, cellular sacs, taking the place of the brain ; c, occipital bone ; d, spinal corcl.","page":955},{"file":"p0956.txt","language":"en","ocr_en":"956\tTERATOLOGY.\na hernia. The parietal bones are sometimes present, together with flat frontal bones, and a perpendicular occipital bone, so that the summit of the skull is quite closed, with the exception of a small opening. Fig. 609. shows how the malformed cerebral substance is applied to the medulla spinalis. All the cerebral nerves are present.\nThis form of monstrosity has in general a less brute-like aspect ; the trunk is more evolved, and the whole body in general very heavy.\nFourth Type.\u2014The skull flat, more evolved, but having an opening, through which the brain protrudes as a hernia.\u2014This is what we call a cerebral hernia (hernia cerebri, encephalocele), viz. a tumour covered with the external integuments arising from some part of the surface of the skull, and containing a part of the brain. It has commonly the form of a bag, appended to the posterior part of the skull, and resting on the neck. The head is never turned with the face upwards ; the ears do not rest on the shoulders ; the neck is not wanting. The summit of the skull is flat and closed, and its cavity is too small to include the brain, which for'this reason is placed on its outside, and backwards. The occipital bone has the form of a vertebral arc, which surrounds the brain, lying at the outside. Fig. 610. shows the external appearance of\nFig. 610.\nfM ( , h\nthis monstrosity, flg. 611. the structure of the skull.\nFig. 611.\na, frontal ; b, parietal ; c, occipital, bones.\nIn many of the published observations, a collection of serous fluid accompanied the hernia cerebn, by w'hich a hydro-encephalocele was formed.\nThe situation of the cerebral hernia is in general on the occiput, but sometimes on both sides of the root of the nose (W. Lyon, Kelch) ; above the eye (Adams); on the forehead (Bedard, Saxtorph, Niemeyen, Bredon, Guyenot) ; on the fontanella magna (Held) ; in the parietal bone (Le Dran, Stein, Tren) ; on the glabella, between the orbits (Otto).\nOn a survey of these various types, it appears that they all belong to the same class of monstrosities. The nature of the malformation is in all the same, namely a defective de-velopement of the skull and of the brain. This takes place in different degrees, so as to convey us gradually from the complete want of brain to those cases in which it is nearly perfect, and differing from the natural condition only in situation. The constancy of form is very interesting in this monstrosity, so that the malformed children resemble each other nearly in every museum, and the published observations are quite accordant with the cases now occasionally occurring. This proves that the origin of the malformation cannot be accidental. The want of the neck, w'hich is the reason why the ears rest on the shoulders and the chin on the breast, and which gives to this form of monstrosity such a peculiar character, is often the consequence of the want of some of the cervical vertebr\u00e6 (Rathke, Haller, Otto), or of their mutual coalition (Rathke, W. Vrolik), or of their shortness (Sandifort.) As a transition to the brute form, this shortness of the neck is interesting, reminding us of the condition of the Cetacea. The prominence of the eyes is occasioned by the flatness of the orbits, and by the backward direction of their superior margin. It differs from the manner in which the eyes are prominent in children with internal hydrocephalus. A rich growth of hair is common to all the forms of acrania. Is not this, and likewise the abundance of areolar tissue, to be attributed to a vicarious nutritive function ? The frequent absence of the suprarenal glands (Otto), or at least their imperfection and smallness (Morgagni, Hewson, F. Meckel, Soemmering, W. Vrolik) in all acranial foetuses is remarkable. The capacity for persistent life after birth differs according to the different forms of this monstrosity. Acrania does not seem to interfere w'ith uterine life. The children who are affected with it are all well nourished, and some of them even very large, at the moment of their birth. Nevertheless, they rarely live longer than a few hours. During this short life they offer some symptoms which are attributable to the reflex action of the nervous system ; such as, for instance, muscular contractions when the skin is touched, rejection by the mouth of the recently expressed juice of Pelargonium tomentosum, and the attempt to suck a finger introduced into","page":956},{"file":"p0957.txt","language":"en","ocr_en":"TERATOLOGY.\t957\nthe mouth. In cerebral hernia the chance for the prolongation of life is greater. Some cases are known in which life lasted 20, 30, and even 60 years. When complicated with hydrocephalus, puncture has sometimes been instituted, but without success (Earle). Extirpation produced, in another case, instantaneous death.\nWhat are the causes of acrania? From some of its forms, it is clear that there has been hydrocephalus followed by disruption (Morgagni, Penada, Sandifort, Klein, Otto). In an embryo figured by M. Schroeder Van der Kolk, the summit of the head is extended by hydrocephalus, and has on its superior surface a black gangrenous spot which seems to prognosticate a rupture.\nIn another foetus I observed a fissure in the midst of an analogous spot. According to my opinion, the lacerated bags, which are sometimes found on or in the summit of the naked internal surface of the basis cranii, or at the back part of the more developed skull, are caused by such ruptures. Tiedemann gives a description of such a bag, filled with serous fluid, but not yet burst, and situated upon the head of a foetus, which has the external appearance of acrania. {Fig. 612.)\nFig. 612.\nBut in those cases in which the flat basis of the skull is only covered with a membrane and with cerebral nerves, in those in which there is a spongy substance upon it, and in those in which the skull, although flat, is otherwise complete, not the least probability exists of the rupture of a cerebral vesicle at an early period of formation. I am able to prove this, I think, by a small foetus of two months, in which the superior part of the skull is wanting, and in which a spongy mass occupies the place of the brain.\nit shows that acrania may also be a primitive malformation, occasioned by the simul-\ntaneous malformation of the brain and of the skull. Why I do not impute these malformations to external injury, such as the leaping of a monkey on the belly of a pregnant woman (Sandifort), to a fall down stairs (Pauli), or to the influence of imagination, needs not be demonstrated.\nIII. Fissure of the Back Part of the Body.\nHydrorachis and Spina bifida. \u2014 Fissure of the spinal column (spina bifida), and dropsy of the spinal medulla, occur each separately, or connected together. In the highest degree of fissure, the vertebral bodies even are cleft (J. T. Meckel, Tulp, Fleischmann). Fig. 613. represents such a case, after Cruveilhier.\nFig. 613.\nIn a less degree, the vertebral bodies are complete, but their arcs very defective, being completely wanting, or laterally incurved and fused together. In the lowest degree, the two halves of the vertebral arcs are completed, but not united together, so that posteriorly an open space remains between them, and a fissure occupies the place of the processus spinosi, which are separated into two lateral and equally incurved parts.\nWhen this form of fissure of the spinal column is not accompanied by hydrorachis, both parts of the vertebral arcs are not bent laterally, but meet each other so exactly, that no open space remains between them. Sometimes the fissure is extended over the whole vertebral column {spina bifida totalis), sometimes it is but partially cleft {spina bifida partialis). The partial fissure occurs more frequently in the lumbar than in the cervical region of the column. The cause of the greater frequency of the partial fissure in the lumbar region is to be imputed to the termination of the spinal medulla in this region ; to its expansion there","page":957},{"file":"p0958.txt","language":"en","ocr_en":"958\nTERATOLOGY.\nunder the form of cauda equina ; to the larger sheath formed there by the dura mater ; and to the very limited tendency which the osseous nuclei of the lumbar and sacral vertebrae show to unite themselves into an arc, which therefore remains always open at the inferior part of the sacrum. Although it occurs sometimes alone, this sort of fissure is generally accompanied with dropsy of the spinal medulla (hydrorachis), that is to say, with a sac of a reddish-violet colour, in which fluctuation is easily discerned. Its external covering is sometimes formed by the skin, and then it has the usual colour of the body ; the skin, however, does not in most cases cover the whole surface of the tumour, but ceases at its circumference, and the rest of its surface is only covered with the dura mater. When the child lives, the dura mater becomes, after some time, thicker, harder, and more solid. When the tumour is covered with the skin, the dura mater is to be found under it. These membranes become often so thick, and so intimately united together, that it is nearly impossible to separate them from each other. The serum contained in the tumour is of a very variable quality, principally composed of albumen, mucus, gelatin, and muriate of soda (Bostock). It is effused between the pia mater and the arach-noidea, or between this and the dura mater, or in the primitive canal of the spinal medulla. If this canal remains open, the hydro-rachis is in general accompanied with hydrocephalus internus. Sometimes these sacs are found on more than one spot of the spinal medulla, or divided into two by a septum. The size of the sac varies, and the complication with hydrocephalus is very dangerous If this is the case, the artificial opening of the sac has a very injurious effect. Convulsions and exudative inflammation are in most of the cases excited by it. In some very rare cases the operation was attended with success. Sir Astley Cooper healed hydrorachis by reiterated puncturing with a thin needle and by compression of the tumour. Dubourg is said to have treated it with success by means of excision of the tumour and bringing together the lips of the wound with needles, in the same manner as in the operation for hare-lip. Beynard tied a ligature round the sac. E. de Thine-court compressed the tumour, after having opened it, with two small rods, which he connected and pulled together by means of ribbons. The noxious effects of hydrorachis after the child\u2019s birth make it necessary to try an operation. Before birth this malformation seems not to have the least influence upon the health of the child : it is well nourished and duly constituted. After birth the noxious effect is modified by the different seat of the tumour. When seated in the lumbar and sacral region, it is the least dangerous. It is known that some individuals have lived with it twenty-eight years. In most cases, however, paralysis of the inferior part of the body is its consequence. Hydrorachis in the cervical region is much more dangerous. One case of this is men-\ntioned in my \u201c Tabulae,\u201d in which death suddenly occurred on opening the tumour.\nBesides hydrorachis, some other malformations of the spinal medulla are observed sometimes to accompany fissure of the spinal column :\n1.\tComplete want of the spinal medulla, commonly connected with acrania ; 2. Its appearance under a cylindrical form, with persistance of the primitive medullary canal (Morgagni, Santorini), which is sometimes double (Gall, Yon Ammon) 5 3. Fissure of the spinal medulla into two juxtaposed cords; so that it seems to be double, which is occasioned by an arrest of developement at that period of its evolution in which the two halves, of which it is formed, are as yet separate ; 4. The presence of a simple nervous expansion instead of spinal medulla; 5. The lamellar form of the medulla ; 6. A too great length.\nBy all this it is proved, that fissure of the spinal column may be accompanied with hydrorachis, and with an imperfect developement of the medulla. They are totally independent of each other, and each is produced by its own cause. It is, however, not very improbable that a voluminous sac on the medulla may prevent the union of the points of ossification, by which the vertebral arcs are to be formed ; but we are not, I think, justified in concluding from this that hydro-rachis is the cause of the fissure of the vertebral column. For it may exist without fissure of the spinal column, if it has not acquired the form of a bag ; and the spinal column may be cleft although the spinal medulla is intact. This leads me to the conclusion, that malformation of the spinal medulla, hydrorachis, and fissured spinal column, do not essentially go together.\nIY. Hydrocephalus congenitus.\nCongenital dropsy of the brain. \u2014Under this name we understand such a great volume of the head in a full-grown f\u0153tus that it opposes in general a mechanical impediment to parturition, which can only be removed by an artificial diminution of the volume of the head. Its forms are \u2014 1. Hydrocephalus internus;\n2.\tHydrocephalus externus.\n1. Hydrocephalus internus is said to exist when the abnormal serous secretion occurs in the ventricles of the brain, wherefore it has also acquired the very rational name of hydrops ventriculorum cerebri. It may be an altogether primitive malformation, when the brain is arrested at that period of its developement in which it has the form of a very thin vesicle, filled with a serous fluid. I have observed this condition principally in Cyclopes, and give an example of it in fig.QU.\nIn such case there is no indication of the hemispheres, nor of the convolutions of the brain, and, in general, no difference to be seen between the white and the grey cerebral substance. In small foetuses of two months, in which the bones of the skull could not yet be discerned, this form of hydrocephalus has","page":958},{"file":"p0959.txt","language":"en","ocr_en":"teratology.\nFig. 614.\nBrain of a new-born Lamb with Cyclopia, a, a, medullary expansion filled with serous fluid ; b, optic nerve ; c, c, peduncles of the brain ; d, pons varolii; e, medulla oblongata; f,f cerebellum ; g, spinal medulla ; 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, the cerebral nerves, existing besides the optic nerve.\nbeen observed (G. Vrolik, Rudolpbi). See fig. 615.\nFig. 615.\n{Altered from Rudolphi by TV. Vrolik.)\nHuman Ovum, with an Embryo of two months, affected with hydrocephalus.\n959\nInternal hydrocephalus is, however, not always occasioned by arrest of develope-ment in an early period of formation, but may be produced by chronic inflammation, (G. Vrolik), to which the child is, without doubt, as much subject during uterine life as after its birth. The principal causes of it seem to be external injuries suffered by the pregnant woman, and sometimes even reiterated contact by the act of copulation, if the pelvis is large, and the womb seated very low. Pseudo-membranes are on this account often found on the internal surface of the expanded ventricles (G. Vrolik), by which the deposition of the serous liquor may be limited to one or more of the cerebral ventricles, so as to produce an a-symmetrical expansion of the head ; this is, on the contrary, symmetrical, if both the lateral with the third and fourth ventricle are equally and universally extended by the fluid. The head acquires, in such case, an enormous, but symmetrical, volume (E. Sandifort, W. Vrolik). The slower such a secretion of fluid takes place, the slower the head increases in volume, and the less it endangers life, and the less the free evolution of the mental faculties is interfered with. Some cases are mentioned, in which life lasted sixty years (G. Vrolik), thirty years (Michaelis), and fifty-fouryears (Gall). It is remarkable that in many of these cases, neither the senses nor the intellectual faculties were in the least impaired. . This proves that the substance of the brain is not altered by it, and that the form only of the brain is changed by the unfolding of its convolutions. This unfolding is the consequence of the pressure which the fluid exercises from the inside towards the outside, and of the thereby augmented volume of the ventricles (Hunauld, Gall). Those who presume that through the influence of the serum exudated in the ventricles the dissolution and even the total destruction of the cerebral substance may be effected, go evidently too far (Cruveilhier). However large may be the surface into which the hemispheres of the brain have been unfolded, the white medullary substance can always be distinguished from the grey (G. Vrolik). The parts contained in the ventricles are sometimes intact (G. Vrolik), but sometimes incompletely developed, and what we should call depressed (Aurivillius, B\u00fcttner, Malacarne, Klein). The corpus callosum assumes a thin lamellar form; the septum pellucidum and the fornix become thinner ; the glandula pituitaria and pinealis deviate in general from their natural condition (Friend, Malacarne, Wrisberg). The cerebral nerves are in general not changed, and the cerebellum is in most cases natural. The lumen of the cerebral arteries is commonly very large (B\u00fcttner), and Friend saw two internal carotids passing through the carotid canal of the right side. In a few cases there was observed a degeneration of the cerebral substance, which resulted in a deranged and feeble state of the mental faculties (B\u00fcttner).","page":959},{"file":"p0960.txt","language":"en","ocr_en":"960\nTERATOLOGY.\nInternal hydrocephalus has always a prejudicial influence upon the condition of the rest of the body, principally upon its nutrition and upon the osseous system, which it predisposes to emollition. It has a very great influence on the bones of the skull. Its effects are : \u2014\na.\tA large expansion of the skull, whilst the face preserves its common shape, and is in great disproportion to fhe enormous circumference of the skull. This disproportion is the most significant symptom of hydrocephalus, and distinguishes it from simple amplification of the head.\nb.\tA protuberance of the frontal tuberosities, which is to be considered as an arrest at an early period of developement, occasioning an enormous augmentation of the facial angle, which greatly exceeds a right angle..\nc.\tA pushing downwards of the orbital parts of the frontal bone, which makes the superior orbital margins to disappear totally, and to form a protuberance with the frontal part of the frontal bone. The eyes thence acquire a strange direction, their axes being turned upwards.\nd.\tA-symmetry of the hydrocephalous head, which is always more or less oblique. This is the effect of the unequal expansion of the brain. To this may also be ascribed the strange form which the skull acquires when it is regularly extended and developed on its fore and lateral parts, whilst the occiput has a very singular prominence. Such a form is, without doubt, occasioned by a regular expansion of both the hemispheres of the brain up- and sidewards, whilst their posterior lobes and the cerebellum have preserved their regular form. The parietal bones are thereby expanded and augmented in circumference, whilst the occipital bone, not participating in the expansion, is disproportioned to the rest of the skull. The parietal bones are removed from it, so that, during the primitive ossification, an interval is formed, which is afterwards filled up with Wormian ossicles.\nRot less singular is the form of the head and skull, when, probably on account of the position of the head in the womb (as is the case in a partus pedibus pneviis), the pressure of the fluid has been exercised principally downwards, so as to extend chiefly the lateral parts of the head.\ne.\tAn abnormal disposition of the cranial bones. The fontanell\u00e6 acquire, in the first instance, a very large dimension, and some parts of the cranial bones remain cartilaginous, which parts are, in a more advanced period, filled up with Wormian ossicles. Baillie asserts, that sometimes the already formed sutures are opened by the serum exuded in hydrocephalus internus. In other cases, the want of closure of the sutures is to be imputed to a too great thinness of the bones.\n2. Hydrocephalus externus is by some (Monro, Wrisberg, Hartell) erroneously considered as the result of hydrocephalus internus, followed by laceration of the cerebral hemispheres.\nIt is proved, by a great many observations, that such a laceration occurs very seldom. The fluid is, in most cases of hydrocephalus externus, exuded on the surface of the brain. This may be the consequence of an arrest of developement, as I observed in a cyclopic lamb, but it may also be produced by inflammation. The serum is accumulated between the dura mater and the skull, or between the two layers of the arachnoid membrane, but in most cases its situation is between the dura mater and the arachnoid membrane. In all these cases the brain is strongly compressed, shrunken, and hard (Kaltschmidt). Dullness and somnolence are, according to Frank, the consequences of hydrocephalus externus, and convulsive affections those of hydrocephalus internus.\nY. Acephali, or F\u0153tus without a Head.\nWhen we observe the foetus in its first periods of developement, the head is not yet clearly distinct from the trunk. From the third lo the fifth week of gestation, the head, not previously discernible, grows so rapidly, that it has in the fourth week acquired the same volume as the trunk. Now the developement of the foetus is sometimes arrested at that early stage when the head is not yet distinguishable ; the result of such an arrest must manifestly be an acephalus. This denomination is, again, as erroneous as many others ; for not only the head, but many other parts, are wanting. The question remains whether a more appropriate name could be given. Gurlt tried to do so, but, I fear, not with good success. He calls the lowest form of acephali amorphus globosus, which is a true contradictio in adjecto. I think it therefore proper to preserve the old name of acephali, to which I refer, as has been done by Tiedemann and G. Yrolik, nine types, for which I think it not necessary to give special names.\nFirst Type. \u2014 Acephali in the form of a rounded mass, without any indication of extremities. \u2014 Examples have been given by G. Vrolik, Bland, and W. Vrolik, all of twins. The rounded mass is covered with the skin ; it contains an intestinal fold, and receives the insertion of the umbilical cord. In general there is found in it the rudimental indication of vertebrae and of spinal medulla.\nSecond Type. \u2014 Acephali in the form of a rounded mass, with indication of feet. \u2014 The chief observations of this form have been given by G. Yrolik and Clarke, in cases of twins. They have an umbilical cord, rudi-mental external genital parts, and an anal orifice, with an imperfect abdominal cavity, in which are contained an intestinal loop formed by a colon and c\u00e6cum, and kidneys. Consequently all the thoracic viscera, the liver, the spleen, pancreas, stomach, and the small intestines, are wanting ; but there is a rudiment of a nervous system, a tolerably complete right inferior extremity, a pelvis, and a left separate foot, without femur and crus. (Figs. 616, 617.)","page":960},{"file":"p0961.txt","language":"en","ocr_en":"TERATOLOGY.\nFig. 616.\n\nHuman Acephalus, born along with a well-formed child.\na, the right foot with five; b, the left, with three toes ; h, the female genitals ; i, the anus ; c, tumor formed by the umbilical cord ; d, e, f g, eminences covered by the skin.\nFig. 617.\nThe same Acephalus with dissection of the skeleton.\na, a, the only obvious inferior dorsal vertebra, with a pair of ribs ; 1, 2, 3, 4, 5, lumbar vertebrae ; b, sacrum ; c, c, d, iliac bones ; e, femur ; f bones of the foot.\nThird Type.\u2014Accphali in which the trunk is more developed, without a head and thoracic or superior extremities, but composed of an incomplete trunk, ivith an imperfect inferior extremity. \u2014 In the lowest grade of this monstrosity may be ranked an acephalus observed by Ruyseh, consisting only of a leg. Somewhat more perfect is the acephalous inferior extremity of a goat, mentioned by Hayn. It consisted of a pelvic bone, with the other bones of the inferior extremity, some muscles, the vessels and nerves of the femur, which were probably connected with the umbilical cord of the perfect goat born at the same time as the acephalus.\nFourth Type. \u2014 Acepliali in which the trunk is more developed, without a thorax and without superior limbs, and composed of an abdomen, genital organs, and two inferior limbs. \u2014 The hypogastrium and the two inferior limbs are, then, more or less completely formed parts. With exception of one, ail\nVOL. IV.\n961\nthe observations which we know of it are of twins, and in one case of three children born at one birth. In many it is proved that the mother of the acephalus has been often fecundated. They are rarely full-grown at birth, and they have in most instances a placenta common to them and the well-formed child, but with a separate cord ; the foetal membranes also appear to be common to both. The cord of the acephalus contains sometimes two, sometimes three or four vessels (T. H. Kalck). The integuments of the monster, truncated at its upper part, are irregularly tumified, by a large quantity of thick, pale, or yellowish subcutaneous cellular tissue. Interiorly there are lumbar vertebrae, with a pelvis, and the bones and muscles of inferior limbs, besides the spinal marrow and its nerves ; the lumbar and sacral parts of the sympathetic nerve ; blood-vessels without a heart, of which the arteries are connected with the umbilical arteries, and the veins with the umbilical vein ; a loop of intestines ; uropoietic, and genital parts. All the other parts are wanting.\nFifth Type. \u2014Acephali in which the trunk is much more developed, with an imperfect thorax, composed of some dorsal vertebrae and ribs. The superior limbs are wanting.\u2014 The only difference between this and the preceding type is in the more complete trunk, there being a thorax superadded to the abdomen. In all the other points the structure resembles that of the fourth type ; they are\nFig. 618.\nHuman Acephalus born along with a well-formed child, a, cutaneous fissure in the lower part of the thorax ; b, umbilical hernia, under which are the male external genital parts.\n3 Q","page":961},{"file":"p0962.txt","language":"en","ocr_en":"The skeleton of the foregoing Acephalus. a, mobile bone connected with the single cervical vertebra.\nalways twins, and not full grown. As far as it has been mentioned by different observers, there is either a common placenta, with two cords (Ponjol), or with one cord split into two (Mery) ; or there are two placentae connected together (Herholdt) ; or there are two totally separate ova, with a double placenta (Monro). The external appearance differs from that of the fourth type, by greater length, and less truncated upper part of the body, in which a feeble indication of head may sometimes be visible (Ponjol, Prochaska). The integuments are as in the fourth type ; the toes are generally malformed ; the arms and the external genital organs are often abnormal. To the lumbar part of the spinal column is joined an imperfect osseous thorax, sometimes with cervical vertebrae (Hevermann), but without thoracic viscera. The diaphragm exists in most cases. There are vessels without a heart, which cohere with the umbilical vessels. The viscera of the epigastric region are commonly wanting ; Atkinson mentions only a liver. In some intestines can be recognised either as intestina tenuia or crassa. The uropoietic organs, and the internal parts of generation are commonly present. There is in all a spinal marrow. The observations as to the nervous system are very incomplete. (Scefgs. 618, 619.)\nSixth Type. \u2014 Acephali with a trunk composed of a thorax and an abdomen, and with two superior and two inferior limbs. \u2014 When the trunk is more developed, the thorax becomes more convex, is more distinct from the abdomen, and supports two superior limbs. These acephali, too, are twins, at least in the greater number of the cases. They are often not full-grown, and borne by women who have frequently been pregnant. The placenta is in general common to the two foetuses, but with two cords. The thorax is more perfect than in the fifth type ; the upper part of the body terminates not in an obtuse end, but in a broad and flat surface, havirg a fissure in the midst, with an indication of a head. The sternum is often rudimentary, and the osseous frame of the superior limbs is very incomplete. To the spinal column are added cervical vertebrae, and sometimes a confused indication of cranial bones. There is usually a diaphragm, but neither heart nor lungs. There are commonly two vascular trunks, an arterial and a venous. With the venous is connected the umbilical vein ; and from the internal iliac arteries arise the umbilical arteries. There are uropoietic organs, and an intestinal canal, with a c\u00e6cal termination ; and sometimes a liver. This latter is, however, sometimes wanting, together with the spleen and the pa* cr\u00e9as. In the intestinal tube there is no meconium, but only a mucous substance. The nervous system is very incomplete ; but there is constantly a spinal marrow with the abdominal part of the sympathetic. I have observed distinct muscles, of which the presence has been denied by others.\nSeventh Type.\u2014Acephali in which some cranial bones are found. \u2014 This has been observed by Herholdt, in a monster, born twin with a well-formed child, of a mother who had five other children. There was an amorphous head, with an indication of eyes and nose, but without ears and mouth : the rest of the body was much deformed. Of the cranial bones, the condyloid and vertical portions of the occipital only could be distinguished. There was no trace of facial bones. Analogous observations have been made by Curtius and Otto.\nEighth Type.\u2014 Body and extremities perfectly well developed, and having a neck, which is wanting in the other types. The neck is surmounted and terminated by the ears. \u2014 This is the form to which Gurlt gives the name of perocephalus aprosopus. I have met with it in the lower animals only. The body and the limbs are perfectly well developed ; on the perfect neck are placed two coalesced ears, behind which there is an imperfect cranium, composed principally of the cranial, minus the facial, bones. In all this the deformity makes a transition towards an imperfect formation of the face. (Figs. 620, 621.)\nNinth Type. \u2014 Acephali ivhich are composed of the trunk only, without the least indication of superior or inferior limbs. \u2014 Only one case of this monstrosity is known, observed by Vallis-neri. In a foetus of a very mature period of","page":962},{"file":"p0963.txt","language":"en","ocr_en":"TERATOLOGY.\n963\nFig. 620.\nThe superior cervical part of a perocephalous lamb, terminated by the ears which are coalesced with each other.\nFig. 621.\nThe skeleton of the parts represented in fig. 620., with the trachea and the oesophagus, a, squamous part, and b, condyloid part of the occipital bone ; c, petrous ; d, squamous, part of the temporal bone ; e, parietal bone ; f auditory bones.\nevolution, the head, the superior and the inferior limbs, were wanting. There existed only a trunk, which contained a tolerably large heart, imperfect lungs, a malformed liver, a stomach, and an intestinal canal.\nFrom this survey of the characteristics which distinguish the acephali, we learn that they are born with two, three, or four other foetuses at one birth. Can this quantitative multiplication of the children be the cause of the qualitative malformation of one of them ? This is probable by the great fertility of the mothers of acephali, which also indicates\nthat these monsters are produced by an arrest of developement. It is very easy to reduce their external appearance to the early periods of developement, in which the head is not yet distinct from the trunk, and in which the limbs are not yet protruded. It is worth mentioning that the abdominal cavity, with the kidneys and a part of the intestinal canal, are the most constant organs, which is very interesting with reference to the genesis of the intestinal tract. In the monstrous births of the second, third, and fourth type, there is only a colon, while in those in which a thorax is superadded (as in the fifth and sixth types), there is also an intestinum tenue with the c\u00e6cum. I regard this as a confirmation of the statement, that the formation of the intestinal canal commences at the two extremes, and proceeds from these to the middle part.\nIn the same manner the uniformity of circumference of the whole intestinal tube is an arrest of developement at an early period of embryogenesis, to which may also be referred the caecal beginning, and in many cases even the caecal termination of the intestine. The frequent deficiency of the liver is the consequence of the absence of the stomach and duodenum, and therefore a sign that the liver is a protrusion of the mucous membrane of the intestinal tube. The connexion between the containing and the contained parts is also very distinctly proved by the acephali. The very general presence of the lumbar part of the spine determines the existence of kidneys ; that of the pelvis, the existence of the urinary-bladder and of the genital organs. The very imperfect condition of the thorax is in relation with the absence of the heart. The presence of vessels without a heart demonstrates that the circulation of the blood can be carried on by these alone, and that the formation of vessels is quite independent of that of the heart. The profusion of cellular tissue, by which the swollen appearance of the acephali is produced, may be formative substance, which has not been employed in the production of the other parts of the body, and which has therefore grown rather abundant. In this manner many of the peculiarities of the acephali can be reduced to fixed principles.\nVI. Want and defective Formation of the Trunk* (Acormia'f).\nThe highest degree of this kind of monstrosity is where neither trunk nor limbs are formed. Lycosthenes, Rudolphi, and Nicholson describe monstrous births, in which the head is the only part formed.\na. Sometimes only a part of the head is ormed, of which I saw an example in a monstrous foetus born with a well-formed calf. The tongue was the only well-developed part in it. This shows that in the absence of all the central organs, heart, lungs, skeleton, and brain, there may be a well-constituted skin\n* The word trunk is here used to include the extremities.\nf From \u00e0, privativum, and Kopphs truncus.\n3 4 2","page":963},{"file":"p0964.txt","language":"en","ocr_en":"TERATOLOGY.\n964\nsurrounding an amorphous mass of cellular tissue, and only a single well-formed organ. I have given a fuller account of this case in my Tab. lxii. figs. 4, 5,6. Therefore we may conclude that each part is formed sponte su\u00e2, and that it is in its evolution quite independent of the rest of the body.\nb.\tA less degree of malformation is when the superior part of the body is formed without the inferior limbs. Fig. 597. gives a representation of this monstrosity, of which a succinct account is to be found in my Handbook, D. ii. Bl. 100, and Tab. lxiii.\nc.\tIn a more perfect developement of the trunk one of the extremities may be wanting.\nWe call this malformation monopodia ; in it one of the inferior half-parts of the body has not been formed. It makes a transition to those monsters, in which the inferior extremity of the body tapers gradually into a tail-like form, which has given to them the name of monstra Sireniformia.\nd.\tSympodia or Siren-like form is the fourth species of defective formation of the trunk. The single inferior extremity is com-\nFig. 622.\nUromelia.\nFig. 623.\nSympodia.\nposed of the elements of two, and articulates with a pelvis, which is not formed, as in monopodia, by one bone, but by a coalescence of two. In most of them the partially double, partially single inferior extremity terminates in a caudal point ; on account of which the name of Sirenes has been adopted. To this imperfection are added closed anus, defect of external genital parts* and the existence of but one artery in the umbilical cord. The malformed inferior extremity has not always the same form. Therefore we admit three varieties:\u20141. Without a foot, Sirenomelia of J. G. St. Hilaire ; 2. With a single foot, more or less complete, Uromelia of J. G. St. Hilaire ; 3. With a double foot. Fig. 622. represents the second, and fig. 623. the third variety.\nBy this survey of the four types of defective formation of the trunk is proved that they form a very natural series, in which we are gradually inducted, from the total want of a trunk to monsters in which inversion of the inferior extremities is the only deviation from the natural form. The same regularity is here to be observed as in every other class of monstrosities. It is therefore impossible to ascribe their origin to accidental external causes. Meckel has opposed his own","page":964},{"file":"p0965.txt","language":"en","ocr_en":"TERATOLOGY.\n965\npeculiar and sarcastic wit to this absurd aetiology, and gives the very ludicrous account of a surgeon who supposed that the Sireniform monster had been formed during a very difficult delivery. If it is, on the contrary, an original malformation, it may be asked, what can be its remote cause ? Is it the original want of one of the umbilical arteries ? I should not think so ; for one of these arteries is also wanting in the variety in which all the parts of the two extremities are present, and we know that one of them may * be wanting in a completely well-formed child. (See p. 948.) Another question is, whether sympodia can be attributed to the coalescence of the inferior extremities (Meckel, Kamm, Boerhave, and Cruveilhier). Neither am I inclined to adopt this cause.\n1.\tI cannot imagine a coalesence of bones so complete, that through these could be formed one single extremity.\n2.\tIt is impossible to explain by it the imperfect condition of the leg and of the foot in the majority of cases.\n3.\tFrom such a fusion or coalescence cannot be derived the imperfect state of the rectum, and of the sexual and uropoietic organs.\nIt seems to me more probable that sym-podia is due to some original malformation of the pelvis and its viscera, of which the cause remains unknown. The formation of a head solely, of an incomplete trunk without the lower limbs, or of a single inferior extremity, is certainly to be attributed to nothing else but impeded developement. It shows, moreover, that the different parts of the body are quite independent of each other in their original formation.\ne.\tOriginal defective formation of the pelvis. In a well constituted body the pelvis may be originally malformed, as is proved b}r the oh* liquely narrow pelvis of Nazele, and by the transversely narrow pelvis of Robert ; of which malformation the cause is to be found in the imperfect formation of the sacrum.\nf.\tDefective developement of the spinal column. This has been principally observed in calves. It is too short, defective, more or less incurvated, and some of the vertebrae fused together. The head is situated at a short distance from the thorax ; the tail and the anus are reflected to the dorsal surface ; the pelvis is too narrow, and turned upwards at its posterior part.\nVII. Defective Formation of the Extremities.\nThe origin of many malformations of the limbs may be referred to the early periods of embryogenesis. But for some of them this is impossible.\n1. Want of all the extremities is an arrest of developement at that period, in which the limbs are not yet formed, and in which small tubercles occupy their places. Sometimes the superior extremities only are. wanting, which urges the inferior extremities to acquire a sort of dexterity by which they may in some measure supply the place of the superior limbs*\nOf all the examples which are known of it, that of Thomas Schweicker is the most memorable. The inferior limbs only are rarely\nFig. 624.\n3 (i 3","page":965},{"file":"p0966.txt","language":"en","ocr_en":"966\nTERATOLOGY.\nwanting, and the cases few in which there is but one superior or inferior extremity.\n2.\tWant of the intermediate parts in the extremities, so that the hand is attached immediately to the shoulder, and the foot to the hip. \u2014 This may happen in one or in more extremities. Of the last, a very interesting example occurred in the person of a certain Marco Catonze, of whom I represent the external appearance and the skeleton in figs. 624, 625., referring for more details to my Tab. lxxvii.\n3.\tLimbs too short. \u2014 All their parts exist in such case, but are too short, as if they were not full-grown. The malformation is however not limited to the extremities, but extends over the trunk and the head. The head has in all the known cases the aspect of hydrocephalus. The neck is short and broad, the trunk short and swollen, and the limbs short, broad, and thick. Scemmering and Otto ascribe this to congenital rachitis. But according to my opinion it ought to be attributed to defective developement, which is confirmed by the dissection, performed by C. Mayer, of such a monstrosity.\n4.\tLimbs which seem to be truncated.\u2014 Sometimes the fore-arm and the leg terminate abruptly like stumps, and present the appearance of cicatrices. \u00cf saw this on the four extremities of a calf, of which I have represented the external form and the dissection in my Tabulae lxxviii. and lxxix. In many ot the known cases this defective condition of the limbs seems to be the result of arrested developement. In some others, however, it is the effect of mutilation produced by the constriction of the umbilical cord, or by pseudomembranes. Montgomery has given many examples of it in his article F\u0153tus in this Cyclopaedia. It is an interesting fact that from these stumps may grow rudiments of fingers, as Dr. Simpson showed me during the visit which I paid him at Edinburgh.\n5.\tDiminished number of fingers and toes.\u2014 The highest degree of this malformation is the existence of but one finger or toe. Sometimes there are only the thumb and the little finger, as may be seen in a preparation in the museum of Ilovius at Amsterdam. The greatest transition towards the natural condition is the presence of four fingers or four toes.\n6.\tCoalesced fingers and toes. \u2014 In otherwise perfect limbs it is possible that hands and feet may be arrested at that inferior degree of developement, in which they are not yet separated into fingers and toes. The child is then born with fingers or toes, which seem to be coalesced ; but that is nothing more than a fallacious appearance. The malformation consists really in absence of fission. Of this there are different degrees : a, complete absence of fingers and toes** instead of which there is a common mass ; b, connection of the fingers and toes by means of a membrane ; c, the adhesion limited to the posterior parts of the fingers and the toes, while their anterior parts are completely free. All this may be seen in figs. 626, 627, 628\nFig. 626.\n(After Otto.')\n7. To all these malformations of the limbs ought to be added the abnormal direction of 'f the foot; but this is fully considered in the ; e\nt\n","page":966},{"file":"p0967.txt","language":"en","ocr_en":"TERATOLOGY.\t9G7\narticle Abnormal Conditions of the Foot in this Cyclopaedia.\nVIII. Cyclopia.\nUpon this interesting malformation, which for many years was the object of my own investigations, I should have much to say ; but my friend Paget has already given a succinct survey of its different forms in his learned Article Nose, to which, therefore, I refer. I beg leave here to add to the observations which I have published in my former works upon the origin of Cyclopia, a few additional remarks on the subject. Is it an arrest of developement? It cannot be denied that many deviations of the parts in Cyclopes may be referred to a previous natural form. For example, in one of my published cases the optic lobe and the brain formed one continuous part, which is certainly an early natural condition. It is also certain that the disposition of the hemispheres of the brain in Cyclopes, which appear to be a single vesicle, accords with the vesicular state of the brain in the first period of its developement, and that the unprotected situation of the ganglia of the brain, of the cerebellum, and of the medulla oblongata, may be considered as a foetal condition. But, as to the eyes, it is not so certain that their singleness is the result of an arrest of developement. E. Huschke has, however, maintained the opinion, that the eyes are formed by a single vesicle, which becomes separated into two ; but from the more recent and accurate investigations of Bischoffj we must conclude that the optic lobes are from the beginning separated and double, taking their origin from the anterior cerebral vesicle, and that from an abnormal condition of this last, by which the rudiments of the eyes approach each other and fuse together, may be derived the cause of Cyclopia. If this observation is true, of which it is difficult to retain the least doubt, Cyclopia really appertains to the Verschmelzungs Bildungen of Meckel in an early period of developement. Perhaps it may be compared with the metamorphosis of the eyes in Daphnia, Cypris, Polyphemus, and Cyclops, in which there are originally two vesicular bulbs, which subsequently coalesce into one. But however this may be, it remains certain that the malformation of the cranial and facial bones in Cyclopes is the consequence of the abnormal condition of the brain and of the visual and olfactive apparatus.\nIX. Deficiency of the \u00dcnderjaw ('Monotia).\nWant of the under jaw often coexists with Cyclopia. By this complication is formed a peculiar series of monsters, which make a gradual transition to those in which, notwithstanding the presence of two eyes, the under jaw is absent. I refer to this the following species.\n1. Total defect of the opening of the mouth,\u2014 as observed by me in a lamb, in which also\nthe ears were removed to the basis of the head and coalesced. The under jaw was totally absent ; and behind the coalescent ears there was an osseous vesicular cavity, formed by the bulbous tympanic cavities, united together.\n2.\tThe opening of the mouth represented by a fissure at the inferior surfaee of the face. \u2014 The rest of the external appearance is similar to the first species. The under jaw is wanting, but there is a rudiment of a tongue.\n3.\tToo short an under jaw. In man and the lower animals the under jaw is sometimes incompletely developed, and more depressed posteriorly than it ought to be. This original brevity of the under-jaw is the cause of a great many ulterior deformities.\nWithout doubt, these three forms of monstrosity make a continuous series. They consist, as Bischoflf says, in an imperfect developement of the first visceral arc, by which the under jaw and the bones connected therewith are either wanting or defectively formed, the result of which is, that the ears are removed to the basis of the head, and there become fused together. The toial defect of the opening of the mouth is the highest, the too short under jaw the least degree of malformation.\nHerewith I conclude my brief account of the monstrosities resulting from arrest of developement. The description of the congenital abnormal condition of the different apparatus would oblige me to surpass the due limits of an Article for this Cyclopaedia, which already, I fear, may be considered rather too long ; and I think this the less necessary, because a great deal of information about them may be found in the Articles Anus, Diaphragm, F\u0153tus, Hermaphroditism. I therefore pass on to a succinct description of a second group of monstrosities.\nB. Monstrosities produced by Excess of Developement.\nI. F\u0153tus in F\u0153tu.\nThe human foetus may be included in another foetus, or adhere to its body. This may happen in two different manners : \u2014\n]. A f\u0153tus more or less perfect contained in the cavity of the body of its twin-brother or sister.\na,\tIn the uterus. \u2014 The foetus would be pregnant in such a case at the moment of its birth. The observations given of it are, however, somewhat apocryphal.\nb.\tIn the abdomen. \u2014 Ina case recorded bjr Fattow, there are, in a foetus of seven months, two rudiments of foetuses contained in its abdomen. Such observations are also given by Reiter, Heminger, Pacini, and E. Philips. In general, the rudiments of a second foetus are very imperfect, and included in a sac. Sometimes, however, they are more complete, which was, for example, the case in an observation of Young, of which the preparation is\n3 Q i","page":967},{"file":"p0968.txt","language":"en","ocr_en":"908\nTERATOLOGY.\npreserved in the splendid Museum of the London College of Surgeons.\nc.\tIn the anterior mediastinum. \u2014 As in a case recorded by Gordon, in a female of twenty-one years.\nd.\tIn the scrotum and the testes. \u2014 Such cases have been noticed by Rosenberger, Hartmann, D. S. J. Wendt, Velpeau. Sometimes the rudiments of a second foetus are found in the interior of the testis, sometimes at its exterior surface.\ne.\tIn the stomach.\nf.\tIn the intestinal canal. \u2014 Highmore has given such a case in a youth of fifteen or sixteen years, in the gut of whom an acephalus was found.\ng.\tIn the orbit. \u2014 According to Barnes.\nh.\tAt the tentorium of the dura mater.\ni.\tAt the palate. \u2014 It is then in the form of a fungous excrescence, consisting of the rudiments of a second foetus (Otto, Sandi-fort, Ehrman, Stadenski).\n2.\tThe more or less developed rudiments of a f\u0153tus adhere, in the form of a tumour, to the external surface of a second body, and aie covered by the external integuments.\na.\tTo the cheek.\u2014 G. Vrolik observed in a new-born male child, a sac of large circumference, covered by the external skin, and adhering to the region of the left cheek, but without communication with the mouth. In this sac there were tuberculous cartilages, osseous nuclei, and organised parts of indefinite form and composition.\nb.\tTo the neck.\u2014 According to Joube.\nc.\tTo the epigastric and umbilical region. \u2014 As recorded by E. B. Gaither.\nd.\tTo the sacral and perineal region. \u2014 This is the most frequent mode of adhesion, as is proved by a great many observations, among which those of Himly and of Fleischmann deserve special mention. This adhesion takes place in different manners : 1. by external cellular tissue ; 2. by internal union with the abdominal and pelvic cavity (Himly, Schau-mann, and Stanley) ; 3. by communication with the spinal canal. There is sometimes no vascular communication between the foetus and its appendix (W. Vrolik) ; and in other cases there are large branches going from the arteria sacra media of the foetus to the sac. In general, the sac has its own integuments, over which passes the skin of the foetus. The genital parts and the anus are always quite separate from the sac, which merely lies in apposition with them. In the majority of the known cases, the rudiments of a foetus contained in the sac are but confused and ill-determined organic substances, intermingled with a few osseous and cartilaginous nuclei. In one case it was possible to recognise the cranium with the face and the naked encephalous masses (Wedemeyer) ; Mayer and Blizard found an intestinal loop ; Himly saw distinct super-maxillary bones, and rudiments of temporal, frontal, and sphenoid bones, &c.\nIf we take a survey of all the cases which are designated as f\u0153tus in f\u0153tu, it is clear that some may be compared with parasitical diseases formed in the interior of the body of the fcetus. I presume that this is the case, when the mass which is found consists only of hair, fat, teeth, and some osseous nuclei, \u2022 contained in a cystic tumour. In other cases . the rudiments of a fetus are included with a more or less perfect indication of an ovum in the body of a second fetus, or adhere externally to it. The large number of theories on the origin of this monstrosity have been criticised by Himly. It is certain that none of * them can be maintained. It is most pro- 1 bable that the foetus in f\u0153tu is an incomplete effort to form a double monster. In this sense, some cases of foetus in f\u0153tu make a transition towards that form of double monsters which is named heteradelph.\nII. Double Monsters, in which one of the Fee-\ntuses is more or less perfect and the other\nmerely an Appendix to it (Heteradelphi).\nUnder this name of heteradelphs, which we owe to Geoffroy St. Hilaire, we understand J that species of double monsters of which one fetus is large and perfect, and another, or part of another, adheres to it like a parasite. They should be considered as twins, of which one has been developed at the expense of the other, which other sometimes becomes partially included in its body. According to the more or less perfect state of the appendix, they are reduced to different species.\nFirst Species. \u2014 The appendix consisting of a head only. \u2014 This may be connected : \u2014\n1.\tWith the epigastric region (Winslow, ; Hesse),\n2.\tWith the cranium (E. Home),\n3.\tWith the back (Chabelard),\n4.\tWith the palate (Hofmann), or\n5.\tWith the under-jaw of the perfect fetus (Geoffroy St. Hilaire, G. Sandifort).\nSecond Species. \u2014 The appendix consists of more or less developed extremities only. \u2014\u2022 Supernumerary extremities, more or less developed, are connected with some part of the body of a perfect fetus, as :\n1.\tPelvis and two inferior extremities connected with the epigastric region of the perfect fetus (Serres, E. Sandifort, Trombelli, Mayer, Winslow, Reschel, Buxtorff, Cantwell, Lycosthenes).\nThe appendix is sometimes more, sometimes less perfect; sometimes connected with the sternum, sometimes with the epigastric region or in communication with them by a cylindrical cutaneous prolongation. In the appendix are regularly formed organs of generation, kidneys, an intestinal loop in communication with the intestinal canal of the supporting fetus, and vessels which anastomose with those of the latter. The adhering parasite is therefore one with its supporter.\n2.\tPelvis and the two inferior extremities connected with the lateral wall of the abdomen of the perfect fetus (W. Vrolik).\n3.\tPelvis and two inferior extremities con-","page":968},{"file":"p0969.txt","language":"en","ocr_en":"TERATOLOGY.\nhected with the pelvis of the perfect foetus (Numan, Osiander, Haller).\n4. Separate anterior or posterior extremities connected with some part of the perfect foetus (W. Vrolik, Von Baer).\nAll these varieties are indicated under the names of gastroviele, pygomele, and melomele.\nThird Species. \u2014 The appendix is an ace-phalus with four extremities. \u2014 The union has as jet been observed only at the epigastric region of the supporting f\u0153tus, through which the abdominal cavity was common to^ the two bodies. In the appendix the genital organs existed, but the anus was closed. In many cases, the evacuation of urine has been observed; the appendix showed circulation of blood ; it had its own temperature, and was dependent for nutrition on the chief or perfect body. In the interior were found uropoietic organs, vessels connected with those of the chief body, and an imperfect intestinal canal (Otto, Serres). In the supporting foetus are sometimes found traces of double organs (Otto, Serres, Rosenstiel).\nFourth Species. \u2014 The appendix a complete body with a head and four extremities (Bartholinus). \u2014 This form of heteradelph makes the transition to anterior duplicity. The appendix has but to be more equally proportioned to the chief body, and a completely double monster is formed. The best example of this occurred in the person of a certain Lazarus Colloredo, who lived for some length of time. His portrait is given by Bar-tholinus.\nThis very peculiar appendix never took food, nor had it evacuations of fasces. But the organic and the animal life appeared to be very well developed, as its cutaneous exhalation, its movements of different parts of its body, and the fact of its sleeping, showed.\nThe common character, by which this whole class of heteradelphs is distinguished, consists in the comparatively smaller size, and, in general, the defective developement, of the part which is termed the parasite. Imagine this difference removed by the fuller developement of the parasite, by its obtaining all its own organic apparatus, and by its growing pari passu with the other, and an exact idea of complete duplicity will be formed. It will be observed also, that in the several members of this class there is a regularly graduated series, from those in which the superfluous part is only an ill-developed limb, to those in which the parasite differs from the chief in nothing but its inferior size and its dependence for nutrition. The cases of the last kind are, however, rare. I know but three, of which that of the said Lazarus Colloredo, described by Bartholinus, is the most remarkable. Much more commonly the parasite, even when it possesses its full numerical complement of parts, bears many signs of defective developement ; it is hare-lipped, or a cyclops, or has atresia ani, or some other malformation from arrest of developement. All this seems to me to prove, that in heteradelphs there are\nalways the rudiments of two bodies, though one or both may be defective.\nThe beings thus formed have rarely lived many years after birth, and the histories of the few that have survived are, for the most part, well known in the records of medicine. Perhaps the most remarkable is that of the Chinese A-ke, of whom and his parasite little models are to be found in most of the anatomical museums of Europe. The parasite\u2019s life is, in general, only vegetative. In one of the three cases, indeed, in which it possessed all the constituent parts of a body, it moved its limbs, and appeared to have its own sensations ; but in the others, less perfectly formed, even these signs of individual life were absent ; and in only one, that of the Chinese A-ke, had the man who bore the parasite any voluntary power over its limbs. The nutrition of the parasite appears to depend entirely on the body to which it is fixed, and through which it both receives its nutritive materials and discharges its excretions. The one increases and decreases in size with the other; and, of course, the parasite dies with the individual to which it is attached. The influence which, in its turn, it exercises on its supporter is not always important. In the heteradelphs that die early, death commonly ensues from the malformation of the main body ; if they survive, the parasite seems to do harm only, as an ordinary tumour would, by its weight, and by abstracting a certain amount of nourishment, so that those who, thus burdened, have grown up to childhood or manhood have usually been thin and delicate, like men subject to some unnatural waste. But, nevertheless, it will always be better to tolerate this evil than to risk an operation of removal, when the results of all the examinations yet made prove that the parasite is deeply and by important organs connected with its supporter. The only exception which I know to the correctness of my opinion is the case in which Mr. Blizard removed, with complete success, from the sacrum of a child, a congenital tumour, which seems to have been a parasite.\nIII. Double Monsters.\n1. Anterior duplicity.\nIt has been already said that some of the rarer kinds of heteradelphia approximate closely to the double monsters. In all the cases that stand nearest to the transition, the parasite has been found adherent to the epigastric . region ; and the kind of duplicity which is most closely related to them, is therefore that in which the two bodies adhere by their anterior surfaces, or what we call anterior duplicity.\nThe most complete examples of duplicity yet known are found in this class, whose distinctive characters are, that two bodies, in a state of nearly equal developement, are placed exactly opposite to one another, with their sterna connected together, and with their abdominal cavities either partially or completely coalesced. Here, however, as in all","page":969},{"file":"p0970.txt","language":"en","ocr_en":"970\nTERATOLOGY.\nthe other classes, examples are found of gradations towards a state of singleness. For instance, the upper parts of the body being completely double, the lower are united, so that there are but three limbs, or only two lower or posterior limbs. And, in like manner, although in many cases the bodies are alike in size and other characters, yet there are many more in which one has so far surpassed the other, both in size and in stage of develope-ment, as completely to fill up the series between this class and the decided heteradelphs. Whilst in the latter case we find close approximations to duplicity, there are even among the most perfect double monsters peculiarities which constantly recall to mind the parasitic attachment of the heteradelphs.\nWith this nearly perfect external duplicity there sometimes, but not always, corresponds an equal duplicity of organs. The umbilical cord may be single (Parsons, Otto), notwithstanding the heart is perfectly double. The two umbilical arteries belong but to one child ; the umbilical vein bifurcates and enters both bodies. In another case (Cruveilhier), the single umbilical cord had two veins and four arteries, and the heart was externally single, and in its internal parts imperfectly double. In a third double monster (Otto), the umbilical cord had five vessels, two umbilical veins, and three arteries, and in this there were two hearts. In a fourth double monster the heart and umbilical cord were single. The bond of union, as far as the skeleton is concerned, is commonly a tough fibrous connection between the lower extremities of the sterna and the ensiform cartilages, which are set directly opposite to one another.\nThe rest of the sterna and the ribs are usually distinct, and the thoracic cavities are thereby separated. In this case there are commonly two separate and perfect hearts ; but in the cases in which the sterna are more completely fused, or (as happened in one case) entirely absent (Comm. Litt. No-rimberg.), only a single heart, or one partially double, with, for instance, two ventricles and four auricles, or otherwise malformed, is found. But it is particularly remarkable that in these, as in all other kinds of double monsters, there is no constant relation whatever between the respective states of the external and the internal organs, for the condition of the two digestive canals, even in those which are externally almost alike, is subject to still greater varieties than the condition of the heart. The abdominal organs are always in some degree connected ; \u2014 the two livers are usually continuous.\nA spleen, pancreas, and stomach are commonly found in each body, and each stomach has its own duodenum,, which, after some length (being continued into the jejunum) unites with the other to form a single tract of small intestine, which again divides into two canals, leading respectively to the large intestine of each body. The lungs, the urinary, and the genital systems are always double. The most remarkable example of this class was the well-\nknown Siamese twins. When exhibited, they were not exactly opposite to each other, but stood side by side, or, rather, obliquely one by the other ; but this position, there can be little doubt, was acquired by the attempts which they had instinctively made to separate from each other in walking, or in lying and sitting down, and by the extension they had n thus effected in their bond of union, which was considerably more slender than in any other yet described. It was quite impossible for them to remain always face to face; therefore their bodies acquired an oblique direction, in which they also moved. The consequence J of this was, that the right limbs of the one and the left of the other individual were the principal organs of movement ; and that the intermediate limbs, that is to say, the left of the one and the right of the other, remained merely passive (Dubois). The one individual was stronger than the other, and seemed to overrule him. But, nevertheless, in organic and animal relation of life they seemed to be independent of each other. Each had his own circulation of blood, his own respiration, and digestive functions. There did not seem to ^ be a large anastomosis of vessels between the two bodies. But, by analogy with the fore-said cases, we may conclude that these twins are connected by the ends of their sterna, and by some of their abdominal organs. As a proof of this connection, may be adduced the result of the observations of Mr. Mayo, communicated at the Conversazione of the College of Physicians March 8th, 1831, that when either of the youths coughed, the bond of union swelled up in its whole length, proving that they had but one peritoneal cavity, of which a trans- * verse prolongation passed through the connecting medium. And, therefore, I should conclude, that an attempt at separation could not be made with probability of success. The probability of having to cut through a piece of liver, or a peritoneal canal, must render an operation unwarrantable, unless, indeed, after the death of one of the bodies during the healthy state of the other. The case reported by K\u00f6nig has scarcely authority enough to support a contrary opinion.\n2. Lateral duplicity.\nThe varieties of form in anteriorly duplex monsters are closely limited by the partial nature of the union of the sterna and the nearly complete distinctness of the thoracic cavities, and hence of the whole upper part of the body. In the next class, which I call lateral duplicity, there is no such limit ; and between the highest degree of duplicity found in it and the lowest, or that in which the duplicity is most nearly reduced to singleness, there is a far more numerous series of intermediate forms than in any other of the types of double monsters. In lateral duplicity, the two bodies are not set opposite to one another, but are turned sideways from one another. They have a common thoracic cavity, for the formation of which (at least, in the highest degree of duplicity,) the right ribs of one body, and","page":970},{"file":"p0971.txt","language":"en","ocr_en":"TERATOLOGY.\t971\nthe left of the other, proceed towards the anterior and posterior aspects, and are there connected with an anterior and posterior sternum. The best idea of the construction of this osseous fabric may be formed by supposing the two complete chests of two bodies to be set one against the other, and that then the anterior extremities of the right ribs of the right body, and those of the left ribs of the left body, unite with one sternum and pull it forwards, while, in the same manner, the left ribs of the right body, and the right of the left, unite on the posterior aspect with the other sternum, and carry it backwards. The consequence is, that the two vertebral columns are turned away from one another, and that the parts above and below the thorax are double. By the formation of this common thorax, the lateral is distinguished from the anterior duplicity, in which the thoraces are commonly connected only by the points of the sterna, and, as to their cavities, are separate. And with these differences of external construction, others not less important, of internal arrangement, coincide, which fully justify the separation of the two forms, however similar the external appearances of many of the examples of either may be.\nThe numerous varieties of lateral duplicity may be divided into two principal sets. The first begins with the complete duplicity of the whole body, and ends with its perfect singleness ; in the second, the duplicity of the body remains, but the head gradually becomes single. The forms included herein, of which 1 have given ample accounts elsewhere, may be briefly summed up as follows.\n1.\tComplete duplicity: \u2014 all the external parts and sometimes the abdominal and pelvic viscera double, \u2014 one common double-sized thoracic cavity, formed in the manner just described, and containing four lungs, and (in all cases with which I have been acquainted) only one heart. The examples of this form are very numerous, and are to be met with in all the large museums of Europe.\n2.\tIn the examples of this second group, which exhibits the first step towards singleness, one of the sterna may be traced in a succession of specimens, becoming gradually narrower, and permitting a closer approximation of the two corresponding upper extremities, till, in some examples, they are completely united, and there are found only three limbs above, with three or four below. The two juxtaposed scapulae, for example, are merged into one, or they remain separate, but have only one humerus between them, and this splits below, to articulate with two fore-arms ; or there is but one fore-arm, and this bears supernumerary fingers. In short by a great variety of modes there is a general tendency towards union of two of the upper extremities.\n3.\tIn the third group we have a repetition of the same series of changes in the lower limbs, as in the second was traced in the upper ; here, as there, presenting numerous\nvarieties, in the last and lowest of which only three lower limbs, and the third of these ill-formed, are found.\n4.\tThe third limb has now gradually disappeared, and, with a complete duplicity above the pelvis, there are but two limbs below it, and these well formed. In this class is placed, with many others, the Ritta-Christma monster, described by Serres, which lived to eight months, and the still more remarkable example mentioned by Buchanan, of a two-headed man, 28 years old, who lived in the reign of James III. of Scotland.\n5.\tThe union proceeding, and this simplicity of the lower part of the body being retained, examples come next in which the upper parts also are united ; the two superfluous upper limbs being united into one, presenting a single upper-arm, with a double fore-arm and hand, or a single upper-arm, fore-arm, and hand with ten fingers, or only a mal-formed limb, or a mere projection, occupying the place of the superfluous limbs.\n6.\tEven this last indication of duplicity of the upper parts ceases, a scapula only remains, or this also is absent ; and next, one of the sterna having disappeared, and the vertebral columns having been connected on the corresponding side by their respective ribs united into single arches, these now become gradually shorter, and the columns approach each other more and more nearly, till they are connected by only a cartilaginous substance in the place of ribs, or are at some part fused together.\n7.\tIn this next group both the upper and lower parts of the body are single ; the vertebral column is single below the cervical region, or exhibits only a trace of duplicity (to which something similar is often presented by the sternum), but at the cervical region becomes double, and on each portion bears a head. Of this also I have published many examples.\n8.\tIn the eighth group the extent of that cervical part of the column which is double becomes less and less.\n9.\tIn the ninth group, the two heads are seated on an apparently single neck, in which all the cervical vertebrae are single, or only bear traces of duplicity, except the first two, or the first alone.\n10.\tHitherto the duplicity of the head was perfect ; in this group the two heads also begin to coalesce, and, in a considerable number of cases, gradations are traced in which the adjacent ears are very closely approximated, and the heads are united behind. Then there are cases in which one ear only is placed between the adjacent surfaces of the two heads, and this disappears gradually, and at last totally. Next in order are the cases in which the adjacent ears being lost, the two adjacent and middle eyes first become very close, and then occupying one orbit finally coalesce. Next come those cases in which there is such a union of the heads, that the two upper jaws are articulated with one lower jaw; and, lastly, those in which the head is doubled only in individual parts or in which","page":971},{"file":"p0972.txt","language":"en","ocr_en":"972\nTERATOLOGY.\nthere is one perfect heart, with some imperfect part or parts of another attached to it.\n11.\tThe eleventh group of this division includes the cases of lateral duplicity, in which the body is single in the middle, but doubled above and below (or in brutes anteriorly and posteriorly). In these, which are of rarer kinds, a single neck bears two more or less completely separated heads. The vertebral column is for a considerable length single, but at its lower part again divides, and bears two sets of lower extremities.\n12.\tIn the twelfth group the body is single above and doubled below.\n13.\tIn this there is a tendency towards singleness, or even complete singleness, of the head, but all parts of the trunk and all the limbs are doubled, an arrangement by which, as already stated, these form a series entirely distinct from the rest. In some of these cases the two heads are found coalesced below ; in others, to which the name of janiceps has been given, one face is directed backwards and the other forwards, the remainders of the two heads being merged into one ; in others, one face is perfectly, the other very deficiently, developed ; in others there are only the indistinct traces of a second head presented in the existence of one or two ears on the posterior aspect of the more perfect one ; in others, this trace of duplicity is still less evident ; and, lastly, in the remainder of the group, it is entirely lost, and one head only, which may be well or ill formed, is found upon the double body.\n3.\tInferior duplicity.\nMy third division of double monsters includes the cases in which there are two complete bodies with the lower portions of their respective trunks united, so that there is a head with upper extremities both above and below (the bodies being placed in the same straight line) and on either side of the part at which they meet two lower limbs. One may best conceive this arrangement by supposing two children stuck together by their buttocks, and so fixed with wide-spreading lower limbs, as may be seen in fig. 146. of the second volume of this Cyclopaedia. A common body is thus formed with a head at each end, with two upper limbs both above and below, and with two lower limbs, one belonging to each foetus on the right and two on the left of the united portions. A few cases only of this remarkable monstrosity are recorded ; and in these the duplicity was not always complete, but exhibited in some the same tendency towards singleness as was noticed in the others. Thus in some there were but three lower extremities ; in others there were but two, or two with a third ill-developed on the other side: and, again, in other groups there were those which have a perfect head at one end of the trunk, but an imperfect one or none at all at the other.\nThese monsters have been known to live a considerable time, their capacity for life being probably owing to the separation of the hearts and the absence of malformation in the more\nimportant organs of the body. The umbilical cord is single, and never has a double set of vessels ; an apparent proof (confirmed by similar examples in other classes) that the one body is not formed of the materials of two ; a conclusion which is supported by the coincident singleness of the anus and urinary bladder, and the union of the intestinal canals.\n4.\tPosterior duplicity.\nThe fourth chief form is posterior duplicity, in which two bodies are united by their backs, or a part of them. The union may be at the pelvis (which is most common), and occurred in the well-known Hungarian sisters, who lived to their twenty-second year ; or at the back of the vertebral column, or at the back part of the heads.\n5.\tSuperior duplicity.\nThe fifth is the superior duplicity, in which the two children are connected by their skulls, the bones of which are united so as to form a single skull. In these also the place of union varies greatly. The frontal bone of one coalesces with the parietal or the occipital of the other, or the foreheads are attached to one another, or the side of one head to the front of the other. But all these are very rare, and of each kind only one or two examples can be found on record.\nAll these are true double monsters. Of trip/ed-bodied monsters but one instance is known in the human subject (Atti dell\u2019 Academia de Cattania., t. viii. p. 203., 1834).\nTo conclude the description of duplicity, those which occur in individual parts of the body, the rest being single, viz. in the head, chest, abdomen, and limbs, ought to be recorded ; such as, for example, two mouths, supernumerary teeth and horns, two oesophagi or duodena, double hearts, or supernumerary cavities in one heart otherwise well formed, a double penis and urethra, a double clitoris, supernumerary breasts, kidneys, vertebrae, ribs, fingers, toes, or whole limbs. But for all these I refer to my monograph.\nAt present I prefer to give all those considerations upon the origin of double monsters, of which this highly interesting subject is capable. From all the facts I have published,\nI point out the following generalisations : \u2014\nThe double monsters form collectively one class of organic beings, which, however different in their several degrees of malformation, may be arranged in one continued series. As the lowest degree of duplicity, may be mentioned that of a single part of the body ; for example, a double or supernumerary finger ; as the highest, a complete double monster with two heads, four upper and four lower limbs, and two trunks, such as the Siamese twins. And between these two extremes there are different forms of duplicity, which gradually run one into the other.\nThere is no positive or constant relation between the external and the internal organs as to their degrees or modes of duplicity. In the completest duplicity of the exterior, for","page":972},{"file":"p0973.txt","language":"en","ocr_en":"973\nTERATOLOGY.\nexample, the heart is often single, or even shows signs of having been arrested in its developement ; and, on the other hand, in the more nearly single forms, the heart is usually either partially or completely double. The histories of the cases of anterior and lateral duplicity, which I have given in my monograph, furnish abundant proofs of this. Nor is there any closer relation between the condition of any other internal organ and that of the exterior, than there is between it and the heart ; for in nearly complete external duplicity any of the internal organs may be single ; when there are two trunks indeed, the urinary and genital organs are commonly double ; but as for the stomach, the liver, and the lungs, the correspondence between them and external duplicity follows no other rule than that where there are two necks there are two tracheae and two oesophagi, and as a consequence the lungs and stomach are also doubled. When in like manner the stomach is double, each has its spleen and pancreas ; but the state of the liver is very variable ; sometimes there are two, sometimes but one with a single or double gall-bladder; and these differences often occur in the same form of external duplicity.\nParts placed on the surface of the body are more liable to multiplication than the internal organs, and duplicity of a single part is therefore much less rare than the formation of a complete double body. The upper half of the body is more frequently doubled than the lower, probably in consequence of its earlier developement and the admitted preponderance of the upper parts of the body. The union of the two bodies takes place only between similar parts. The more each of the bodies is developed, the less is the bond of union between them, as the examples of the Siamese twins and the Hungarian sisters sufficiently prove. And with this law is connected another, namely, that the probability of growing up is greater in the same proportion as the bond of union is smaller, and the coincident fusion of internal organs less, as these two and other double monsters prove. So also the further the several organs are from the situation at which the bodies are united, the more perfect they are, \u2014 one body is almost always less developed, than the other: in the heteradelphs this is always the case, and in others the difference between the two bodies, though less evident, is scarcely less constant than in them. There are not commonly any signs of a double monster having been at first two individuals. For except in the cases of posterior and superior duplicity, and some singular examples of attachment of the umbilical cord of one foetus to the head or the body of the other, there is never more than one placenta and one cord, and the latter usually contains only a single set of vessels, which divide when they reach the abdomen. And even in the posterior and superior varieties of duplicity it is not yet certain that there are two placentae ; in some cases the placenta was positively single, and\nin the remainder it has very rarely been examined. A last general rule is that in double monsters the twins are of the same sex. There is no well proved exception to this important rule.\nWhat explanation can be given, after all these facts, of the origin of double monsters ? On this subject, three hypotheses ought to be mentioned : 1. The double monster has been supposed to have proceeded from two distinct embryos, which have become united in the course of development ; 2. It has been held to have originated in a single germ, which has become double, or has been subdivided ; and 3. The germ has been regarded as abnormally compound from the first, implying that the organs and parts composing the double monster are at once produced from this germ, without either separation or coalition of its parts other than belong to the natural process of developement. On the comparative merits of the first and second hypotheses, as parts of the general doctrine of monsters, one of the most interesting physiological discussions extant is recorded in the M\u00e9moires de l'Acad\u00e9mie des Sdences de Paris, between 1724 and 1743. The chief disputants were Lemery and Winslow ; the contest lasted nineteen years ; it engaged the attention of all anatomists, and called forth writings by Haller and a crowd of authors of less note, and was only terminated by the death of Lemery. Every argument that could be founded on the knowledge of those days was brought forward, and the subject was, for the time, utterly exhausted ; but the facts accumulated in later years have furnished such volumes of additional evidence, that the same question, between original and acquired monstrosity, as far as it relates to double monsters, may even now claim to be discussed.\nIt is certain that two ova may be formed in one Graafian vesicle (Yon Baer, Bischoff, Bidder). The equally well-known fact, that the common fowl sometimes produces double-yolked eggs, naturally led at one time to the opinion that the formation of double monsters might be attributed to the developement and subsequent union of the embryo in each yolk ; an opinion which has been adopted by some on very insufficient grounds, as it does not appear to be warranted by any direct observations made upon the result of the incubation of double-yolked eggs, and is at variance with much of what is known of the structure and mode of union of the two embryos composing a double monster.*\n* I have here made use of the words of Professor Allen Thompson, who, in a remarkable memoir upon double monsters, published July, 1844, in the London and Edinburgh Monthly Journal, fully entered into the topic, and illustrated the genesis of double monsters by some very interesting observations. I lament that he was not acquainted with my monograph upon the same subject, nor with the succinct account which Mr. Paget has given of it in the British and Foreign Medical Review for October, 1841. He would have found in it a great deal in corroboration of his own opinions, in which I universally agree with him.","page":973},{"file":"p0974.txt","language":"en","ocr_en":"974\tTERATOLOGY.\nC. F. Wolff has distinctly affirmed, that a double-yolked egg is equivalent to a double ovum ; that the produce of its incubation would be twins ; and that a double monster can only proceed from a single yolk containing a double germ. Examples of double embryos of birds sometimes occur at the full period of incubation, in which both are complete, and there is no union, excepting at the umbilicus. It is barely possible that each of these embryos may have been developed from a separate yolk, and that in the course of incubation the two yolks have come to coalesce, in consequence of external pressure, or other causes. Towards the conclusion of the period of incubation, when the yolk usually enters the abdomen of the foetus, we may suppose, in the case before us, a partial entrance of the common yolk into the abdomen of each embryo, and thus, upon the subsequent contraction of the umbilical aperture, the union of the two embryos may be effected. We learn, from the accurately-detailed observation of C. F. Wolff, previously referred to in my monograph, that two completely separate foetuses may be formed in the bird\u2019s egg upon a single yolk, and within a single germinal and vascular area. The egg, in this instance, had been incubated six days, and both the embryos were at once so complete and so distinct, that there is no reason to believe they would have been united till the period when the entrance of the yolk into the abdomen of both, and the contraction of the umbilical apertures, had brought them together.\nIn a dozen double-yolked eggs, which Prof. Allen Thompson brought to incubation, he never succeeded in obtaining a double monster, nor even two embryos, at the full period, from any of them. In several instances he found that one yolk only had been productive.\nAll this proves that such double-yolked eggs may produce twins, but that the formation of a double monster is not dependent on them. It is highly probable that in the same manner, in Mammalia, the arrival in the uterus of two impregnated ova, in close proximity with one another, will be attended with the production, not of a double monster, but of twins.\nThe complete fusion of these twins seems to me quite impossible. One of my chief arguments against the hypothesis of fusion of originally separate germs is the important fact, which I derive from my own investigations and from those of others, that double monsters form one series, among whose several members the degrees and modes of deviation from singleness gradually increase, and pass, without one abrupt step, from the addition of a- single ill-developed limb to the nearly complete formation of two perfect beings. Now if this be true, no hypothesis can be acceptable if it do not plausibly explain the origin of the whole series of double monsters, or if, though it may suffice to explain the facts in one part of the series, those in another part are opposed to it. And here\nis a fair objection against the hypothesis of fusion of two originally perfect and separate embryos. Grant that we might explain by it the formation of several of the more perfect instances of duplicity; still, if the same hypothesis is altogether opposed by the simpler forms of duplicity, it is surely not tenable. For example, it cannot account for the existence on a child\u2019s sacrum of a shapeless mass, containing an isolated portion of intestine, as in Mr. Hanley\u2019s case. And still less can it explain the existence of a superfluous limb ; for the limbs are mere off-shoots, and are produced at so late a period, that if we could imagine two embryos to come in contact by their shoulders or pelvis, and a fusion of those parts to take place, we should still have to explain how one of them, leaving only an arm or a leg behind him, could for the rest of his substance, head, trunk, and all, wholly disappear.\nIt was a main objection against the doctrine of Lemery, that if two germs came in contact by accident (as he supposed), they could not exhibit any regularity in their mode of attachment, but faces would be forced into chests, abdomens into spines, and so on. The moderns, who adopt the same hypothesis, suppose that the ova come in contact not by accident, but by an attraction de soi pour soi, of which the influence is, that the two ova being by accident set face to face or back to back, or in any other way similia similibus, will be drawn to each other, and will unite by similar parts. But, with all respect for the authority of M. Geoffroy St. Hilaire and his disciples (as Mr. Paget elegantly said in his abstract of my monograph upon double monsters), who regard this as \u201c la r\u00e8gle supreme de tous les arrangements et de toutes les modifications organiques chez les \u00eatres compos\u00e9s,\u201d I confess that I can find no good evidence that such an attraction exists. I can see in it nothing more than a very happy expression of a fact, which it in no wise explains. The extraordinary notion of MM. Delpech and Coste, that such an attraction may be the result of electric currents, is certainly no evidence of its existence, this being entirely imaginary. And the reasoning in its favour seems no better than the facts, for I can find nothing but this kind of circle : monsters adhere by similar parts, therefore there is an attraction de soi pour soi; there is then such an attraction, and therefore double monsters so adhere. I believe, therefore, that such an attraction is hypothetical ; and if it be so, surely the hypothesis which involves it and an accident as essential elements is less probable, as well as less sufficient, than that which I maintain. It is scarcely better than Lemery\u2019s, of mere accident; for it requires not only the accident of a particular position of the ova, but that of their being of the same sex, which has been said previously to be the general rule for double monsters. After all this, we conclude with the words of the learned Wolff, published in 1773 : \u2014 \u201c Patet, igitur, monstra composita non sic oriri, ut","page":974},{"file":"p0975.txt","language":"en","ocr_en":"TERATOLOGY.\n975\naliquando duo separati integri embryones fue-rint, qui dein contingentes et compressi, par-tibus eorum nonnullis destructis, aliis coalitis et commixtis, concrescerent in unum novum compositum corpus ; ea vero, qu\u00e6 vel defectu partium vel insolita structura monstra sunt, non ita fieri ut prius integri et naturales embryones fuerint, qui deinde per causas acci-dentales ad generationem non pertinentes mutilati vel transmutati fuerint; sed necesse esse, ut utraque monstrorum genera a primis suis initiis jam ejusmodi monstra fuerint.\u201d\nIf we are right in not admitting the existence and the fusion of two distinct germs, we necessarily adopt the opinion that only one germ has been formed, and that in this excess of formative power lies the cause and origin of every monstrous duplicity. Mr. Allan Thompson demonstrated, in coincidence with Wolff, Von Baer, and Reichert, as may be seen in the wood-cut (fig. 629.), that\nFig. 629.\nFrom a fowVs egg after sixteen or eighteen hours\u2019 incubation. Magnified four times, a, the germinal area of the cicatricula ; b, the transparent area, containing two primitive traces of embryos ; c c, primitive grooves of the double embryonic trace, on each side of which are seen the lamin\u00e6 dorsales.\n(After A. Thompson.')\nupon one yolk, and in one germinal membrane or blastodermatic vesicle, there may be formed, in birds, two primitive grooves, which, in their ulterior increment, shall probably form a double monster, as may be seen in a goose\u2019s egg, after five days\u2019 incubation, represented after Allan Thompson, in fig. 630. By the formation of such a double primitive groove in a single ovum, we may explain the origin of the principal types of double monsters ; and on this point a recent observation of Valentin seems particularly worthy of notice, viz. that in which an injury, inflicted on the caudal extremity of an embryo on the second day, was found, on the fifth, to have produced the rudiments of a double pelvis and four inferior extremities. But if we admit this cause for those large and principal types, we must acknowledge that it is insufficient for the heteradelphs, and for all those cases in which, the body remaining single, some parts are\nFig. 630.\nt i h k\ni \u00cf\nDouble embryo removed from a goose\u2019s egg. after five days\u2019 incubation. Magnified four times, g, the common heart ; h, rudiments of the superior, i, of the inferior extremities ; k, the common cephalic fold of the amnios ; Z, the caudal folds.\n(After A. Thompson.)\ndouble. For these the excess of formative power is the only explanation we can give. We understand, under this name, not the nisus formations of the ancient physiologists, working as a Feus ex machina, but the physical and vital metamorphoses materice, to which the formation of a new being ought to be attributed. Those who are fond of the modern nomenclature may name it, if it pleases them, typical or organic power. But enough, we admit such a power, of whatever name it may be, and contend further, that different degrees or quantities of excess lie at the origin of all the cases of double monsters, the degree of excess determining in each the degree of duplicity. If a certain excess of power be admitted capable of producing any one case of duplicity, other amounts of excess may be believed capable of producing all the other cases which differ from it only in degree ; and I meant to have proved, in my monograph, and in the succinct survey I have given of double monsters in this Article, that all double monsters may be referred to differences in degree of deviation from the normal singleness.\nBut in many double monsters w^e see excess in one part and defect in another, so that we must suppose, in our hypothesis, that in these cases the power, more or less excessive in quantity, is also wrongly distributed. Nor is this inconceivable ; for since, in the normal developemental power, we must imagine at least two elements, quantity and distribution, and must acknowledge that, for the attainment of a perfect result, the quantity must be distributed in definite proportions to each part, so it is not improbable that, in certain circumstances of fault in the ovum, a normal or an excessive power may be distributed disproportionately in the several parts.\nTo sum up, therefore, our reasons for rejecting the hypothesis of fusion of ova in","page":975},{"file":"p0976.txt","language":"en","ocr_en":"976\tTESTICLE (NORMAL ANATOMY).\nfavour of that of excess or irregular distribution of developemental power, for preferring to regard them as examples rather of singleness tending to duplicity than of duplicity tending to singleness, are briefly these : that it is probable that the whole class of monsters by excess owe their origin to different degrees of one common fault, and consequently that the explanation of their origin ought to be the same for all ; that no kind of fusion can account for the production of supernumerary individual organs, the rest of the body being single ; but that it is not impossible that excess of power in the ovum, which all admit can alone explain the lower degrees of duplicity, may, in proportionally higher degrees, perhaps by the formation of two primitive grooves, produce the more complete double monsters, or even two such separate individuals as are sometimes found within a single amnion.\nBibliography. \u2014 On account of the length of this Article, and the great number of books upon the subject, I shall omit the Bibliography, and refer to the foot-notes as well as to the manuals of Meckel, Rokitansky, Geoffroy St. Hilaire, von Ammon, and my own, in which the bibliography is duly noticed.\n(JV. VroliJc.)\nTESTICLE. \u2014(Human Anatomy). Gr. opxis \u00bb Latin, Testis \u2014 Testiculus ; French, Testicule ; German, Hode ; Italian, Testicolo.\nThe testicle is the gland by which the semen or spermatic fluid is secreted. Two in number, and contained within the scrotum, these organs are suspended at a variable and unequal distance from the abdominal rings, one testicle, generally the left, hanging a little lower than the other. This arrangement prevents collision between these organs when the thighs are suddenly approximated ; one testicle slipping above the other, and thus eluding violence. In cases of transposition of the viscera and blood-vessels, it has been observed that the right testicle hangs lower than the\nleft.\t. t\nThe shape of the testicle of an adult is that of an oval with flattened sides. The organ has two extremities, an antero-superior, and a postero-inferior ; and two lateral surfaces. Its position in relation to the body is rather oblique, its long axis or antero-posterior diameter passing from above downwards and a little inwards. Its edges and sides are convex. Its upper extremity is rounded and capped by the epididymis, which rises above the body of the gland like the crest on a helmet. According to Cruveilhier the testicle measures two inches in length, one inch in breadth, and eight lines in thickness. Sir Astley Cooper makes its long diameter two inches ; its transverse, an inch and a half ; and its lateral, one inch and one eighth. I have found the mean dimensions of the testicle to be one inch and three quarters in length, one inch and a quarter across or in breadth, and one inch in thickness or from side to side. Meckel states its average weight to be four drachms, and Sir A. Cooper about an ounce. I have found the\nmean of these two estimates, viz. six drachms, to be the ordinary weight of the sound testicle of a healthy adult.* There are few organs subject to greater variations in size and weight than the testicle, even in men of the same age and constitution. The testicles also of the same individual rarely agree, the volume and weight of the left being, in general, greater than those of the right. I weighed the testicles of six men, two of whom were killed by violence, and found the left gland heavier than the right in five; in neither of these instances, however, was the difference more thap a drachm. The organ feels tense, compact, and slightly elastic. Its degree of consistence depends more on the tension of the tunica albuginea than on the proper substance of the gland. It is a good deal influenced by the quantity of seminal fluid contained in the tubular structure, and its state of activity or rest; the gland being tense and tumid when the organ is exercised and the tubuli are distended, and soft and flaccid, when they are empty and the gland inactive. The parts composing the testicle may be described under four heads : \u2014 1. The protective parts or tunics ; 2. The proper glandular or secreting structure ; 3. The excretory parts ; 4. The vessels and nerves.\n1. The Protective Parts or Tunics.\u2014 The Tunica Vaginalis. \u2014 This is a delicate serous membrane in the form of a shut sac, which consists of two portions ; an outer one, the parietal, which is free and loose ; and an inner, reflected, visceral or testicular portion, which closely invests the gland. The two portions are connected and continuous with each other. The outer one loosely invests the whole of the testicle except its posterior edge and inferior extremity, parts where the membrane becomes attached to the gland. It is connected with the testicle at about five lines from the lower extremity, and the junction of the two portions is marked by a white and rather irregular line. The uncovered portion of the organ corresponds to the original attachment of the gubernaculum. On the inner side of the gland the membrane, after investing the lower part of the cord to a greater or less extent, is reflected to the epididymis just below its head, and to the posterior edge of the body of the testis, being there separated from the epididymis by the vas deferens and blood-vessels of the gland. On the outer side the membrane entirely covers and closely invests the epididymis, and forms a cul-de-sac, which isolates its middle from the posterior border of the testicle, and in cases of hydrocele is often distended into a pouch. At the bottom of this sac the tunica vaginalis on the two sides comes into close contact, and sometimes there is a communication at this spot between the two. The smooth and polished surface of the shut sac thus formed by the tunica vaginalis is lubri-\n* This nearly accords with Krause\u2019s estimate (M\u00fcller\u2019s Archiv. 1837.) \u2014 who found the mean weight in five instances to he 354*4 grains, or five drachms, two scruples and fourteen grains.","page":976},{"file":"p0977.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\ncated by an albuminous^#uid, having the ordinary properties of the secretions of the other serous membranes. The office of this membrane is to facilitate the movements of the gland, so as to enable it to elude pressure and escape violence.\nIn some adult subjects the tunica vaginalis, which was originally a process from the serous lining of the abdomen, still retains its connexion with that cavity. When the communication is free, the sac is very liable to receive a protrusion of some of the contents of the abdomen, and become the seat of congenital hernia. Sometimes the communication continues through a contracted tubular canal, which, though too narrow to admit the transit of any of the viscera, is open to the passage of fluid. In other cases the obliteration is partial, one or more isolated serous sacs being left along the cord. It more often happens, however, that after the upper aperture of this process has closed a considerable part of it below remains unobliterated, so that the tunica vaginalis extends for some distance upwards in front of the cord. Frequently, also, although the obliteration is complete, remains of the prolongation may still be found in the form of a slender whitish filament, or fibrous process, which is lost in the areolar tissue in the anterior part of the cord, but may sometimes be traced as far as the tunica vaginalis.\nA small body of an irregular shape and variable size, and of a pale red or pinkish hue, is commonly found attached, often by a thin pedicle, either to the upper extremity of the testicle, or at the angle where the tunica vaginalis passes from the body of the gland to the epididymis. It is composed of a dupli-cature of this membrane, containing some fine areolar tissue and a number of small vessels. It occasionally contains a little fat. I have seen this little body in the testicle of the foetus whilst in the abdomen, and, in early life, it is often of proportionally larger size, and of a deeper red colour than in the adult. It is quite distinct from the pedunculated cysts often found attached to the head of the epididymis. This little appendage to the tunica vaginalis seems to correspond with, and to be a type of, the remarkable omental process attached to the superior part of the testicle in the Rodentia and other animals. That it is an unimportant structure in the adult, is shown by its being frequently wanting. It may be of use, however, by slightly increasing the secernent serous surface.\nThe tunica Albuginea, or Tunica Propria, is a dense, tough, inelastic membrane, composed almost solely of white fibrous tissue, analogous to the sclerotic coat of the eye. It completely invests the body of the testicle, but not the epididymis. Its external surface is covered by the tunica vaginalis reflexa, to which it intimately adheres. This tunic is divisible into two layers, which can be separated only by a tedious dissection, but which in certain animals may be detached without difficulty. The branches of the spermatic artery and\nVOL. iv.\n977\nveins ramify in the substance of the tunica albuginea, in canals bearing in their arrangement some analogy to the sinuses of the dura mater, which membrane the outer layer is supposed to resemble. The smaller vessels are chiefly distributed on the inner layer, which owing to its vascularity has been compared to the pia mater investing the brain. At the postero-superior border of the testicle, and a little to its outer side, the tunica albuginea forms an internal projecting body or process, which lodges the blood-vessels and a portion of the glandular structure of the testicle, called the rete testis. This body is named, after the anatomist who first'described it, the Corpus Highmori. It has since, however, been called by Sir A. Cooper the mediastinum testis, and he describes it as being formed by the tunica albuginea, which at that part is divisible into three layers. The first layer turns upon the spermatic cord, and unites with the sheath which covers the vessels. The second layer unites with a similar layer on the opposite side, and forms a thick substance, between the fibres of which interstices are left for blood-vessels and absorbents, whilst the internal layer, uniting with that on the opposite side, as well as with the preceding layer of the tunica albuginea, forms the process called mediastinum, which projects into the testicle between the tubuli, and it is in this substance that the seminal canals of the rete are placed. The mediastinum is therefore composed of two bodies ; the upper placed towards the spermatic cord, the lower towards the centre of the testicle : in the upper are placed the blood-vessels ; in the lower, the canals of the rete. Its length varies from six to eleven lines.\nII. Glandular or Secreting Structure.\u2014 The glandular part of the testicle is very simple, and its tissue is more easily demonstrated than the structure of most other glands. It consists of numerous seminiferous vessels or tubes, supplied with blood-vessels, lymphatics, and nerves. Its colour is a greyish yellow or brown, more or less tinged with blood, and is paler in infants and old men than in adults. The tubes are collected into numerous lobes or lobules, invested by a fine areolar tissue, which, detached from the interior of the tunica albuginea, penetrates the gland, and sends out lateral processes forming septa, which separate and sustain the lobules. These septa at their origin partake of the fibrous character of the tunica albuginea, but as they converge towards the superior border of the testicle, occupied by the corpus Highmori, they become finer, and are gradually resolved into a delicate areolar tissue. The septa are traversed by numerous blood-vessels, which minutely divide in them before being distributed on the seminiferous tubes. Sir A. Cooper states, that the inverted portion of the tunica albuginea, forming the mediastinum testis, sends forth numerous ligamentous cords, some of which pass to the anterior edge of the testis ; whilst others form shorter processes to support and invest the lobes, being met by similar liga-\n3 R","page":977},{"file":"p0978.txt","language":"en","ocr_en":"978\tTESTICLE (NORMAL ANATOMY).\nmentous cords from the inner surface of the tunica albuginea. I have not been able to make out any such ligamentous processes passing into the substance of the testis, as are represented in Sir A. Cooper\u2019s work (part i. pi. 2. fig. 3), which I have no doubt is an exaggerated view of the preparation from which it was taken. The cords described appear to me to consist chiefly of blood-vessels supported by slight fibrous processes from the tunica albuginea and areolar tissue. In a well-injected testicle very little tissue of the nature of ligament can be found between the lobes. The secreting structure of the testicle, like the texture of many other glands does not possess much common sensibility. When exposed in disease it may be probed and injured with the forceps without pain.\nTubuli Seminiferi. \u2014 These tubes, which form by far the greatest part of the bulk of the glandular structure of the testicle, are very numerous, and radiate from all parts of the circumference of the organ towards the mediastinum, making numberless convolutions which progressively diminish as they approach the rete testis. Two or more of the tubuli, being collected together and invested by a common tunic of condensed areolar tissue, form a lobe or lobule of a conical form, its apex terminating at the corpus Highmori. The lobes thus formed are\nFig. 631.\nThe lobes attached to the mediastinum, but artificially separated from, each other. (From a preparation in the Hunterian Museum, formerly in Sir A. Cooper's collection.')\nnot entirely distinct, but communicate with neighbouring lobes : the processes investing them are therefore incomplete, and the lobes cannot be separated from each other without division of some of the seminiferous tubuli. Krause estimates the number of the lobes as varying from 404 to 484.* The tubuli are of a white colour and uniform size, but their calibre differs in different subjects, and varies a good deal according to the age of the subject and the state of activity of the testicles, being larger in young adults and when distended with semen, than in old persons and when the gland is in a state of rest. The size of the ducts also often differs in the two testicles of the same subject. In general the calibre of the tubuli corresponds to the size of the tes-\n* Mliller, Archiv, f\u00fcr Anatomie, 1837, s. 22.\ntide. Observers do not exactly agree in their estimates of the diameter of the tubuli. The average diameter of the uninjected canal is estimated by Muller at of a line ; by Lauth * at y|y of an inch. Krause found the tubuli, when filled with semen, to measure about -Jy of a line, and in old men and youths TJy. Huschkef estimated the ordinary thickness of the whole tube from -i- to yy of a line, and that of the walls from yiy to y^y Owing to the stoutness of the basement membrane, the thickness of the walls of the tubes is considerable as compared with the secreting ducts of other glands, and this accounts for the tubes being able to resist the pressure of a column of mercury in injections. Monro reckoned the number of the seminiferous tubes at 300 ; Lauth made the average number 840, and he estimated the mean length of all the ducts united at 1750 feet. He found the individual ducts to vary in length, the mean being 25 inches. Krause estimated their entire length at 1015 feet. The membrane composing the tubuli is continuous with the mucous surface of the genito-urinary system. It is lined with epithelium, and the spermatozoa are developed from the epi-\nFig. 632.\nGlandular structure of the testicle, displayed by mercurial injection. (After Lauth.)\na a a, glandular substance of the testicle subdivided into lobes, each lobe being composed of convoluted tubuli closely packed ; b, rete testis ; c, vasa efferentia ; d, inflected part of the vasa efferentia forming the coni vasculosi ; e, dilatations of the efferent vessels ; f, body of the epididymis ; y, tail of the epididymis ; h, vasculum aberrans ; i, inflected part of the vas deferens ; k, straight part of the duct.\n* M\u00e9m. de la Soci\u00e9t\u00e9 d\u2019Hist. Nat. de Strasbourg, t. i.\nf Encyclop\u00e9die Anatomique, t. v. p. 347.","page":978},{"file":"p0979.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\t979\nthelial cells. There is no appearance of an intertubular substance ; the ducts are merely connected by a loose network of vessels, and consequently readily admit of being separated and unravelled. The tubes, when successfully injected with quicksilver, form a beautiful anatomical preparation. Sir A. Cooper succeeded in filling the tubes with size injection ; but he has not described the mode in which it was effected, and other anatomists have failed in similar attempts.*\nWhen the tubuli seminiferi are unravelled, they are found to divide and form numerous anastamoses, which increase in frequency towards the circumference of the testicle. (See diagram, fig.633. a1\u00ab1). The tubuli thus form one vast network of communication, so that it is impossible to isolate completely either a duct or a lobule. The credit of making this interesting discovery of the anastamoses of the seminal tubes is due to Lauth. In only one instance did he succeed in finding a duct, terminating in a blind pouch, and this he regarded as exceptional. Blind ends have been found, however, more frequently by Krause. The anastamoses of the tubules have been observed in the rat and other animals as well as in man. The convolutions of the seminal tubes diminish in number as they approach the mediastinum, and cease altogether at a distance of from one to two lines, where two or more unite to form a single straight duct, termed vas rectum, which joins the rete testis at a right angle (a2 a2). The vasa recta are very slender, and easily give way when injected : their calibre, which is greater than that of the seminal tubes, is estimated by Lauth at -^^th\nFig. 633.\nDiagram of the testicle. ( After Lauth.}\na a a, tubuli; a1 a1, subdivisions and anastamoses of the tubuli ; a2 a2, vasa recta.\nThe other references are the same as in fig. 632.\n* Sir A. Cooper\u2019s beautiful preparations of the testicle are preserved in the Museum of the Royal College of Surgeons of England.\nof an inch. Haller reckoned their number at twenty, which is, however, too few.\nRete Testis, as its name implies, consists of a plexus of seminal tubes, which occupies the corpus Highmori, or mediastinum testis. The vasa recta, after penetrating the walls of this body, terminate in from seven to thirteen vessels which, running parallel to each other in a waving course, and frequently dividing and anastomosing, form the rete testis, (b). Lauth found the mean diameter of the vessels of the rete in injected preparations of an inch. According to Prochaska, these vessels are supplied with valves, but such is not the case. Small dilatations, however, are often found in different parts of the plexus.\nIII. The Excretory Parts.\u2014The epididymis, a continuation of the testicle, is a body of a crescentic form, divided into an anterior and upper extremity, called head, or globus major, which is firmly attached to the testicle ; a middle part or body, which is less in size, and separated from the gland by a pouch of the tunica vaginalis; and a tail or globus minor, connected to the testicle by areolar tissue. The volume and weight of the epididymis vary in different subjects, but are proportionate to the size of the testicle. It is longer than the testicle, measuring about two inches in length and four or five lines in width. Its name (from iirl upon, and SlSu^os testis,) indicates its position, which is along the postero-superior border of the gland. The epididymis is chiefly made up of seminal canals connected and supported by a firm resisting areolar tissue. The ducts which spring from the upper part of the rete testis to form the epididymis are termed vasa efferentia. They are usually about twelve or fourteen in number, but vary from nine to thirty. The inflections of each of these efferent ducts are so arranged as to form in the head of the epididymis a series of elongated conical figures called coni vasculosi. These ducts, at their commencement, run straight for a distance of about one or two lines, when they form convolutions which become more numerous and close as the ducts recede from the testicle. Their length varies, the upper being the shortest. Lauth found their average length to be seven inches four lines, and calculating their number at thirteen, he makes the united length of the vasa efferentia nearly eight feet. He states that the efferent ducts diminish in size from their commencement to their termination in the canal of the epididymis, where they are less than the seminiferous ducts of the testicle. (Fig. 634.) As in the rete, round dilatations of variable size are often met with in these ducts. (Fig. 632., e e.) The efferent ducts, after forming the coni vasculosi, successively join a single duct, the canal of the epididymis, at irregular distances, the intermediate portions of the duct varying in length from half an inch to six inches. The efferent ducts are more slender than the canal of the epididymis, and frequently give way under the pressure of the column of mercury when injected. The body and tail of the\n3r2","page":979},{"file":"p0980.txt","language":"en","ocr_en":"980\tTESTICLE (NORMAL ANATOMY).\nepididymis are entirely made np of the convolutions of the single canal in which the\nFig. 634.\nAn efferent vessel and a portion of the head of the epididymis magnified, to show the progressive diminution of the canal of the cone, and the calibre of this vessel, in comparison with that of the canal of the epididymis.\nc, vas deferens ; d, inflected portion of the duct ; e e, head of the epididymis. (.After Lauth. )\nvasa efferentia terminate, closely connected by areolar tissue. Monro described this canal as gradually increasing in size from the head to the tail, and he estimated its calibre about its middle at ^ of an inch. Lauth states that its size is subject to great irregularities in different parts and in different subjects. This anatomist has particularly described the convolutions of this duct, and has shown that they are regularly arranged in four series, which successively increase in size ; the first being the smallest, and the fourth the largest. The arrangement will be understood by reference to the subjoined figure. Monro estimated the length of the canal at thirty feet eleven inches. Lauth found its mean length to be nineteen feet four inches eight lines. The parietes of the canal are strong, and bear considerable resistance. The canal of the epididymis terminates in the excretory duct of the testicle, the vas deferens, and is usually contracted at the part where the two join, which accounts for the mercury when forced into the vas deferens being often arrested at this point. It was calculated by Monro that the semen, before arriving at the vas deferens traverses a tube forty-two feet in length. Lauth, however, makes the whole distance but little more than twenty-two feet.\nVasculum aberrans.\u2014 This name was given by Haller to a blind duct or coecal appendage often found connected either to the epi-\ndidymis or vas deferens. It is more commonly attached at the angle formed by the\nFig. 635.\nCanal of the epididymis partly unravelled, to show the four series of inflections which the duct undergoes in the several divisions of the epididymis.\no, o, first series of inflections ; p, p, second series ; q, q, third series ; r, r, fourth series. (After Lauth).\ntermination of the former in the latter. (Figs. 632., and 633, h.) It forms a convoluted duct as large as the canal of the epididymis, which is contracted at its insertion, and terminates in a blind and often dilated extremity. Sometimes after being dilated for a certain distance it diminishes, and becoming very minute, is lost in the areolar tissue of the cord. It usually passes up the cord for about two or three inches, but has been found to extend as far up as the brim of the pelvis. The length of this appendage when unravelled varies from one to twelve or fourteen inches. The vasculum aberrans is not constantly present ; indeed, Monro found it only four times in sixteen ; but I believe, with Lauth, that it exists more frequently. Occasionally there is more than one, and as many as three have been found both by Lauth and Sir A. Cooper. Hunter regarded these ducts as supernumerary vasa deferentia, of a nature similar to the double ureters.* Miiller states that their office is evidently the secretion of a fluid which they pour into the epididymis.f We have no evidence, however, that the duct serves any particular office.\nVas deferens,\u2014 the excretory duct of the testicle, commences from the tail of the epididymis, and terminates in one of the ejaculatory canals behind the bladder, being in length from fifteen to sixteen inches. Arising\n* Works by Palmer, vol. iv. p. 24. t Physiology, Irans, by Paly, vol. i. p. 45","page":980},{"file":"p0981.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\nfrom the contracted part of the canal of the epididymis at an acute angle, it ascends along the inner side of this body, from which it is separated by areolar tissue and the spermatic arteries and veins. A right or left testicle may thus always be distinguished by the circumstance that when the testicle is in position, the vas deferens is situated on the inner or mesial side of the organ. In this part of its course, for the distance of about an inch and a half, or more, the vas deferens forms numerous convolutions, (Jigs- 632., and 633, \u00bb.), which gradually cease as the duct mounts above the testicle. The inflected part of the vas deferens, when unravelled, was found by Lauth to measure six inches and a half. It afterwards takes a direct course (h) up the spermatic cord to the inguinal canal, passing behind and at a short distance from the spermatic arteries and veins. On entering the abdomen at the internal ring, it quits the spermatic vessels and descends into the pelvis, passing at first by the side of, and afterwards behind and below the bladder, on the inner side of the corresponding vesicula seminalis, the excretory duct of which it joins at an acute angle, to form the ejaculatory canal. The canal of the vas deferens is extremely fine, and its walls are nearly uniform in thickness until it reaches the vesicula seminalis. It is lined by a fine membrane of a mucous character, which is continuous with the urethra. This membrane forms longitudinal folds. The vas deferens is round and indurated,\u2014 harder than any other excretory duct in the body, by which character it is easily distinguished, when handled, from the other parts constituting the spermatic cord. Many anatomists have entertained the opinion that the parietes of this duct are muscular. It is distinctly so in the bear, bull, and other animals. On careful examination, however, of sections of the human vas deferens with the microscope, I could discover nothing more than simple fibrous tissue. Huschk\u00e9 makes three layers of fibres ; two longitudinal, and one circular, situated between them ; the latter being the thickest. The duct has an external investment of condensed areolar tissue.\nIV. The Vessels and Nerves. \u2014 Spermatic Vessels. \u2014 The spermatic arteries, the chief vessels supplying the testicles, arise in pairs, at a very acute angle, from the fore-part of the aorta, immediately below' the renal arteries. Their origin is subject to considerable varieties. The two seldom arise at the same level, and the right is often a branch of the right renal artery. Sometimes one or both come off from the superior mesenteric. Occasionally there are two spermatic arteries on one or both sides, arising in the regular way. All these deviations are more frequently met with on the left than on the right side of the body. Each artery pursues a tortuous course downwards and outwards, passing behind the peritoneum obliquely across the psoas muscle and ureter, to which, as well as to the surrounding areolar tissue, it gives\n981\noff several branches. The artery then enters the inguinal canal through the internal ring, and emerging at the external, passes down the cord, being surrounded in its course by the spermatic veins. The further distribution of the artery is thus correctly described by Sir A. Cooper : \u201c When the artery reaches from one to three inches from the epididymis, varying in different subjects, it divides into two branches, which descend to the testicle on its inner side, opposite to that on which the epididymis is placed ; one passing on the anterior and upper, the other to the posterior and lower part of the testis. From the anterior branch the vessels of the epididymis arise: first, one which passes to its caput; secondly, another to its body, and, thirdly, one to its cauda and the first convolutions of the vas deferens, communicating freely with the deferential artery. The spermatic artery, after giving off branches to the epididymis, enters the testis, by penetrating the outer layer of the tunica albuginea ; and dividing upon its vascular layer, they form an arch by their junction at the lower part of the testis, from which numerous vessels pass upwards ; and then descending, they supply the lobes of the tubuli seminiferi. Besides this lower arch, there is another passing in the direction of the rete, extremely convoluted in its course, and forming an anastomosis between the principal branches.\u201d The testis receives a further supply of blood from anothe\u201d vessel, the artery of the vas deferens, or posterior spermatic artery, which arises from one of the vesical arteries, branches of the internal iliac. This artery divides into two sets of branches, one set descending to the vesicula seminalis and to the termination of the vas deferens ; the other, ascending upon the vas deferens, runs in a serpentine direction upon the coat of that vessel, passing through the whole length of the spermatic cord ; and when it reaches the cauda epididymis, it divides into two sets of branches, one advancing to unite with the spermatic artery to supply the testis and epididymis, the other passing backwards to the tunica vaginalis and cremaster.\nThe spermatic veins spring in three sets from the testicle, one from the rete and tubuli, and another from the vascular layer of the tunica albuginea, and a third from the lower extremity of the vas deferens. The veins of the testicle pass in three courses into the beginning of the spermatic cord ; two of these quit the back of the testicle, one at its anterior and upper part, and a second at its centre ; and these, after passing from two or three inches, become united into one. The other column accompanies the vas deferens. There is also a large vein, just above the testicle, which crosses to join the three columns. The veins of the epididymis are one from the caput, another from its body ; one from its cauda, and another from its junction with the vas deferens, besides some small branches ; they terminate in the veins of the spermatic cord. The veins, after quitting the testicle, become extremely tortuous, and frequently\n3 R 3","page":981},{"file":"p0982.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\n982\ndivide and inosculate in the cord, forming a plexus termed vasa pampiniformia. These communications cease as the veins approach the ring, which they enter, and ascending along with the psoas muscle in company with the spermatic artery, unite to form a single vein which usually terminates on the right side in the vena cava inferior, and on the left, in the renal vein ; though this is subject to some variety. The left spermatic veins pass under the sigmoid flexure of the colon. Many anatomists speak of the spermatic veins as being destitute of valves, which they assign as one of the reasons for the occurrence of varicocele. I have several times injected these veins with alcohol, and on laying them open have observed valves in the larger vessels, and I have also found injections thrown into the veins arrested by the valves. They are seldom seen, however, very near the testicle, or in the smaller veins forming the plexus; nor have I observed them within the abdomen.\nAbsorbents. \u2014 The absorbent vessels of the testicle are very numerous, and arise from every part of its internal structure and coats. They unite to form four or five trunks, which ascend along the cord, and traverse the inguinal canal, without communicating with the glands in the groin, but pass upwards in front of the psoas muscle, behind the peritoneum, and terminate in the lumbar glands on the side of the aorta.\nNerves. \u2014 The nerves of the testicle are derived chiefly from the renal plexus, but partly also from the superior mesenteric and aortic plexuses. These nerves descend in company with the spermatic artery to the cord, where, being joined by branches from the hypogastric plexus, which pass along the vas deferens, they form together the spermatic plexus, the bx*anches of which are intermingled with die vessels of the cord, and ultimately terminate in the substance of the testicle. A few twigs from the external spermatic nerve may also be traced to the coverings of the gland.\nThe Testicle in the F\u0153tus, and its Passage into the Scrotum. \u2014 The testicles are first developed and situated in the abdomen. They originate from the lower part of the corpora Wolffiana, and may be detected at an early period of fcetal existence immediately below the kidneys on the forepart of the psoas muscles, to which they are attached by a reflexion of peritoneum. This membrane closely invests the testicles in the same manner as it covers the other abdominal viscera. The position of the testicle in the abdomen is nearly the same as it maintains after its passage into the scrotum. The epididymis, however, is relatively of a larger size than in the adult, being about one-third that of the body of the organ. Attached to each testicle whilst in the abdomen is a peculiar body, which was termed by Mr. Hunter, who first described it, the gubernaculum, as it was supposed to serve as a guide to the testicle in its passage. It is a soft solid projecting body\nof a conical form, which varies somewhat in shape and size at different periods of transition of the testes, becoming shorter and thicker as the gland approaches the abdominal ring. It is situated in front of the psoas muscle, to which it is connected by a reflexion of peritoneum. Its upper part is attached to the inferior extremity of the testicle, lower end of the epididymis, and commencement of the vas deferens. The lower part of this process passes out of the abdomen at the abdominal ring, and diminishing in substance and spreading, terminates in three processes, each of which has a distinct attachment. The central part and bulk of the gubernaculum is composed of a soft, transparent, gelatinous substance, which, on examination by the microscope, is found to consist of nucleated cells, the primitive areolar tissue : this central mass is surrounded by a layer of well-developed muscular fibres, which may be distinguished by the naked eye, and which can be very distinctly recognised in the microscope to be composed of striped elementary fibres. These muscular fibres, which may be traced the whole way from the ring to the testicle, are surrounded by a layer of the soft elements of the areolar tissue, similar to that composing the central mass ; and, in the same way as the testicle, the whole process, except at its posterior part, is invested with peritoneum. On carefully laying open the inguinal canal, and gently drawing up the gubernaculum, the muscular fibres may be traced to the three processes, which are attached as follows : the external and broadest is connected to Pou-part\u2019s ligament in the inguinal canal; the middle forms a lengthened band which escapes at the external abdominal ring, and passes to the bottom of the scrotum, where it joins the dartos ; the internal takes the direction inwards, and has a firm attachment to the os pubis and sheath of the rectus muscle. Besides these, a number of muscular fibres are reflected from the internal oblique on the front of the gubernaculum. It thus appears, that the attachments of the muscle of the guber-naculum, and those of the cremaster in the adult are exactly similar. I have succeeded in tracing out the former before the testicle has moved from its original position, at different stages of the process of transition, and immediately after its completion ; and of the identity of the two muscles no doubt can be entertained. Carus was of opinion that the cremaster does not exist before the transition of the testicle; but that it is formed mechanically, by the testicle pushing before it the lower fibres of the internal oblique, so as to form the loops of this muscle.* This view which has been adopted by M. Jules Cloquet, and after him by many of the anatomists of this country, is erroneous and inaccurate.!\nThe vessels of the testicle in the f\u0153tus\n* Compartive Anatomy, by Gore, vol. 2. p. 347.\nf Yide Obervations on the Structure of the Gu-bernaculum, and on the Descent of the Testis in the F\u0153tus, by the author, in Lond. Medical Gazette, April 10. 1841, or in the Lancet, of the same date.","page":982},{"file":"p0983.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\t983\narise from\" the nearest largest trunks, and enter the substance of the gland at its posterior part. The artery of the vas deferens, from which the gubernaculum is chiefly supplied, is nearly as large as the spermatic. The long course taken by the arteries and veins of the testicle when in the scrotum is thus explained by the original site of the organ, to which circumstance must also be ascribed the sharp turn upwards of the vas deferens from the epididymis, the two being continuous in a direct line, whilst the testicle is in the abdomen.\nFig. 636.\nDiagram of the gubernaculum and testicle previous to its descent.\n1, the kidney ; 2, the testicle ; 3, 3, the peritoneum \u2019 4, vas deferens passing down into the pelvis by the side of the bladder; 5, the bladder; 6, the abdominal ring ; 7, 7, Poupart\u2019s ligament ; 8, pubic portion of the cremaster; 9, fibres of the cremaster arising from Poupart\u2019s ligament ; 10, portion of the gubernaculum attached to the bottom of the scrotum.\nBetween the fifth and sixth month of foetal existence, sometimes later, the testicle begins to move from its situation near the kidney towards the ring, which it usually reaches about the seventh month. During the eighth month it generally traverses the inguinal canal, and by the end of the ninth arrives at the bottom of the scrotum, in which situation it is commonly found at birth. The testicle, both during its passage to the ring and through the inguinal canal, carries along with it its original peritoneal coat, adhering by the reflexion of this membrane, during the whole of its course to the parts behind, in the same manner as whilst situated below the kidney. The testicle therefore does not pass directly and abruptly into a pouch prepared to receive it, but carries the peritoneum with it, continuing to be connected to the parts behind by the reflexion of the membrane, between the folds of which the vessels and nerves join the gland. In the passage of the testicle from the abdomen to the bottom of the scrotum, the gubernaculum, including its peritoneal investment and muscular fibres, undergoes the same change as that which takes place in certain of the rodentia at the access of the season of sexual excitement ; the muscle of the testicle is gradually everted, until, when the transition is completed, it forms a muscular envelope external to the process of peritoneum, which surrounds the gland and front of the cord. As the testicle approaches the bottom of the scrotum, the gubernaculum di-\nminishes in size, owing to a change in the disposition of its areolar elements ; the muscular fibres, however, undergo little or no diminution, and are very distinct around the tunica vaginalis in the recently descended testicle. The mass composing the central part of the gubernaculum which is so soft, lax, and yielding, as in every way to facilitate these changes, becomes gradually diffused, and after the arrival of the testicle in the scrotum, contributes to form the loose areolar tissue which afterwards exists so abundantly in this part ; the middle attachment of the gubernaculum, which may be traced to the dartos at the bottom of the scrotum, gradually wastes away and soon becomes indistinct, though slight traces of this process often remain to the latest period of life. Thus, after death, in dragging the testicle of an adult out of the scrotum by pulling the cord, the lower part of the gland, which is uncovered by serous membrane, is often found connected to the bottom of the scrotum by a band of firm and dense areolar tissue, which requires division with the scalpel. This band is the remains of the middle attachment of the gubernaculum. In cases in which the testicle has been retained in the groin, I have traced a cord of dense tissue from the gland to the lower part of the scrotum. After the arrival of the testicle in the scrotum, the peritoneum with which it is closely invested, its original envelope; becomes the inner layer of the tunica vaginalis ; whilst the pouch around, which is continuous with it, forms the outer layer, or vaginal sac. Immediately after the arrival of the testicle in the scrotum, this bag communicates with the abdomen, and in quadrupeds continues to do so during life; but in the human subject it soon begins to close, and when the foetus is ushered into the world, the abdominal orifice is often shut, and the whole canal from the ring to the upper part of the gland is, in general, completely obliterated in the course of the first month after birth. The obliteration is effected by an intimate union of the surfaces of the serous membrane. It sometimes does not take place at all*, or is delayed or only partially coming. 637.\nDiagram of the testicle immediately after its arrival in the scrotum, the cremaster being everted.\n1, the testicle ; 2, the shortened gubernaculum ; 3,3, the peritoneum ; 4, portion of the cremaster arising from Poupart\u2019s ligament ; 5 pubic portion of the muscle.\n* The communication constantly remains open in quadrupeds, the chimpanzee, according to Professor\n3 R 4;","page":983},{"file":"p0984.txt","language":"en","ocr_en":"984\tTESTICLE (NORMAL ANATOMY).\npleted. Congenital hernia, or hydrocele is the result of a failure in this process ; and other forms of hydrocele are occasioned by imperfect obliteration of the canal.\nMuch difference of opinion exists as to the immediate cause of the transition of the testicle. Hunter, Meckel, and others came to the conclusion that the muscular fibres of the cremaster are insufficient to bring the testicle further than the abdominal ring and complete the passage. They were not, however, acquainted with the attachment of this muscle to the pubis external to the ring, or it would be difficult to understand why Mr. Hunter, after arriving at the conviction that the cremaster passes to the testicle whilst in the abdomen, chiefly from analogy, was not induced by the same process of reasoning to conclude, that a muscle capable of changing the position of the testicle in brute animals, would be adequate to accomplish the same office in the human foetus. The necessity for some active agent to effect this change in the latter would appear to be greater even than in the lower animals, since, in the usual position of the foetus in utero, the passage of the testicle is contrary to gravitation,* and unaided by the movements of respiration. Now, when we consider the attachments and connections of this muscle in the foetus ; the perfect development of its fibres, as ascertained by microscopical examination ; and the circumstance that there are no other means, no other motive powers, by which this change can be effected, or in any way promoted, I think there is no reason to doubt that the cremaster executes the same office in the human embryo, as that which it undoubtedly performs in certain brute animals at a particular season. The fibres proceeding from Poupart1 s ligament, and the obliquus internus, tend to guide the gland into the inguinal canal ; those attached to the os pubis to draw it outside the abdominal ring ; and the process extending to the bottom of the scrotum, to direct it to its final destination. As the process approaches completion, the muscular fibres which perform so important a part in it gradually become everted, and acquire the new functions of elevating, supporting, and compressing the gland.\nThe Functions of the Testicle. \u2014 The sperm or fluid secreted by the testicle has been considered in the article (Semen). On surveying the structure of this gland, we cannot fail to remark the great extent of secreting surface afforded by the numerous, long, and tortuous tubuli, and the length and complexity of the excretory duct through which the seminal fluid has to pass. The extent of this duct is, indeed, so remarkable, that many physiologists have been led to suppose that the semen is\nOwen, being the only brute animal in which the tunica vaginalis forms a shut sac.\n* For this reason I have departed from the usual custom of English anatomists, and avoided describing the change in the position of the testicle, as the descent.\nfurther elaborated or perfected in its passage through the convolutions constituting the epididymis. An examination of the spermatic fluid taken from the testicle and its duct both in man and in the lower animals, under all circumstances and at all periods, and the varying state of the discharge in cases of spermatic fistula, leave little room to doubt that secretion takes place actively only during the periods of sexual excitement, or under the influence of sexual feelings and desires. From birth to the period of puberty the testicles remain small, and grow but little in proportion to other parts ; but as the body, on the arrival of puberty, becomes stamped with the characters of the male sex, they rapidly enlarge, their glandular structure becomes much more developed, and, being excited, these organs begin to exercise the office of secretion, no spermatozoa being found in them until this period arrives. The age at which the testicles thus become developed varies in different climates, and in different constitutions, and is influenced by the mode of life and circumstances in which the individual is placed. The inhabitants of warm climates reach the age of puberty earlier than those of cold countries. In this part of Europe the change takes place from the age of fourteen to seventeen years, according to circumstances. Unlike the inferior animals, the testicles in man are ready at all seasons to perform their office. The desires subside, and the secretion of semen becomes languid as life advances, though they seldom cease entirely till the age of sixty-five or seventy. Indeed, I have several times discovered spermatozoa in the testicles of men upwards of seventy years of age, and once in the testicle of a tailor who died at the age of eighty-seven. There are instances on record of persons retaining the procreative faculty to the age of one hundred years ; but in these cases, as in the well-known instance of old Parr, the general bodily powers were also preserved in a very extraordinary degree.*\n\u201c To the use of the sexual organs for the continuance of his race man is prompted by a powerful instinctive desire, which he shares with the lower animals. This instinct is excited by sensations, and these may either originate in the sexual organs themselves or may be excited through the organs of special sensation. Thus in man it is most powerfully aroused by impressions conveyed through the sight or the touch : in many other animals, the auditory and olfactive organs communicate impressions which have an equal power ; and it is not improbable that in certain morbidly excited states of feeling, the same may be the case in ourselves. That local impres-\n* Old Parr, who lived to the great age of 152, was dissected by the celebrated Harvey, and it is stated, \u201cGenitalibus erat integris, neque retructo pene neque extenuato, neque scroto distento ramice aquoso tit in decrepitis solet, testiculis etiam integris et magnis.\u201d Bettus de Ortu et Natura Sanguinis, p. 320.","page":984},{"file":"p0985.txt","language":"en","ocr_en":"TESTICLE (NORMAL ANATOMY).\t985\nsions have also very powerful effect Jn exciting sexual desire must have been within the experience of almost every one ; the fact is most remarkable, however, in cases of satyriasis ; which disease is generally found to be connected with some obvious cause of irritation of the generative system, such as pruritus, active congestion,\u201d &c.*\nThe part of the brain which is the seat of the sexual appetite is supposed by the phrenologists to be the cerebellum, between which and the genital organs a close sympathy is said to exist. The grounds for this assumption, and the objections which have been fairly urged against it by sound physiologists, have been stated in a preceding article. (Nervous System, Physiology of, vol. iii. p. 782. s.) No doubt, however, can be entertained that the mind is intimately connected with the procreative faculty, and that the brain controls and animates the desire for sexual enjoyment. An affection of the brain, or the mind, as sudden disgust, arrests the secretion of the testicles and extinguishes all desire as quickly and effectually as a strong mental impression stops the secretion of the gastric juice, and takes away all appetite for food. The influence of the brain on the reproductive function is well illustrated by the occasional effects of injuries of the head. Hildanus mentions the case of a man accused of impotency by his wife, Avho sued for a divorce. Nothing external was defective ; but the man stated that eight years previously he had received a blow on his head by a stick. From that period, \u201c confitebatur penem erigi non posse.\u201d f Dr. Fisher relates the case of a gentleman who, while looking out of the window of a railway carriage, which at that moment encountered a violent collision, received a blow on the head and neck, by which he was stunned. On the second day after the accident he complained of a numbness in his right arm, and experienced difficulty in passing his urine. In the course of two weeks he was able to leave his bed, and walk in the street ; but his vision was defective. Between the fourth and fifth week after his injury he made the discovery that he had lost the desire and physical power for sexual intercourse, and that no amorous sentiment, or the approach of a female could excite it. Under appropriate treatment the bladder gradually recovered its power, and his vision became perfect ; but the numbness of the right arm continued, and the generative functions remained partially impaired. His mental powers, particularly his memory of events, were also for a time seriously affected.j: Dr. Gall mentions that at Vienna he was consulted by two officers who had become impotent in consequence of blows from fire-arms which had grazed the napes of their necks. One of the officers recovered his powers by\n* Dr. Carpenter\u2019s Principles of Human Physio-logy, p. 619.\nf Opera Observationum et Curationum Medico-Chirurgicarum, p. 574.\nJ Case by Dr. Fisher. American Journal of the Medical Sciences, Feb. 1839. p. 357.\ndegrees, married, and became the father of several children.*\nWhen treating of Atrophy of these glands,\nI shall have occasion to mention cases in which the genital function has been permanently annihilated, and complete wasting of the testicles has resulted from injuries of the head. In respect to the mode in which these organs are called into action, they bear considerable analogy to the lachrymal, salivary, and mammary glands, in which secretion is excited both by the influence of the mind and by mechanical contact or local irritation of the extremity of the excretory duct, the glans penis holding the same relation to the testicle as the mucous membrane of the mouth does to the salivary glands, or as the nipple does to the mamma.\nThe influence of the testicles and brain upon each other appears, as has been already observed, to be reciprocal ; for not only may desire be aroused by local irritation and exciting the testicles to secrete, but the passion itself never arises when these glands are removed before puberty and is extinguished by their extirpation afterwards. Nothing, indeed, illustrates more forcibly the intimate relation which the functions of the testicles bear to the mind and character of the individual, and the general organisation of the body, than the effects of castration. When it is performed in early life, the changes characteristic of puberty never ensue. There is a deficiency of the beard; the muscles do not acquire the manly tone and vigour ; the areolar and adipose tissues abound ; the voice retains the high and clear tones of infancy ; and the mind remains deficient in energy and strength. When the testicles are removed after the period of puberty, the eunuch loses in part, though not entirely, his former masculine character. His beard grows less abundantly ; his voice becomes shrill ; and there is diminished energy and vigour in all his sentiments and actions. These changes in the constitution, as well as the loss of the sexual instinct which occur in men thus degraded, do not immediately succeed the removal of the testicles, but take place gradually ; and there are well-attested cases in which desire has been experienced, and connection with emission accomplished many months after the loss of these organs. This shows that the passion is not solely dependent on the secretion of semen, though it invariably declines when the power of procreation becomes lost. The emissions in such cases are imperfect and fruitless, consisting merely of the secretions of the vesicul\u00e6 s\u00e9minales and prostrate. The testicles not being parts essential to life, are subject to different laws from those which regulate the actions of the vital organs. Their functions may be suspended, or they may remain in abeyance for an indefinite period without injury to the glands or any material effect on the constitution. In persons of\n* On the Functions of the Cerebellum, tr. by Combe, p. 46.","page":985},{"file":"p0986.txt","language":"en","ocr_en":"986\nTESTICLE (ABNORMAL ANATOMY).\nrecluse and studious habits the functions of these organs often continue dormant for years. Like the mamm\u00e6 in the unmarried female, though inactive, they remain sound and competent for secretion when duly excited and called upon to exercise their functions. It often happens that the passions are excited without an opportunity being afforded for their gratification. Under these circumstances the testicles become encumbered with secretion which would prove injurious to them were they not relieved by occasional nocturnal emission, or ejaculations of the semen under the influence of dreams during sleep, which appear to be a salutary provision to obviate the inconveniences which might result as well from ungratified desires as from an accumulation of semen in the ducts.\nEnvelopes of the testicle. \u2014The scrotum, or pouch of integument containing the testicles, including the dartos, has already been described. (Article Scrotum).\nSuperficial or external spermatic fascia. \u2014 Beneath the loose areolar tissue of the scrotum is situated a delicate layer of fascia, which is continuous with the superficial fascia of the lower part of the abdominal parietes, and, descending so as to form a sheath to the spermatic cord and an envelope to the testicle, becomes continuous behind with the superficial fascia of the perineum. This fascia is usually very thick and distinct in cases of large and old scrotal hernia.\nCremaster muscle \u2014 Directly beneath the superficial fascia is found the cremaster muscle (so named from npepau to suspend), or, as it has been appropriately termed by Mr. Hunter, the musculus testis. (For description, vide, Abdomen, vol.i. p.6.) The two attachments of this muscle, the external to Poupart\u2019s ligament, and the internal to the os pubis, correspond, as I have previously (p. 983.) shown, to those of the muscle of the gubernaculum, being indeed the same structure, with its relations altered. The actions of the cremaster, which, with a few exceptions, are involuntary, appear to be those of giving a tonic support to the testicles, retracting them to the abdominal rings, and compressing them during the sexual act. In some instances, in boys before the approach of puberty, this muscle has been capable of drawing the gland up into the inguinal canal. Persons are occasionally met with who possess a voluntary power over its actions in various degrees of perfection. Some are able to elevate the testicle on one side but not on the other, whilst others can retract both testicles to the abdominal rings, and retain them there at will. A very remarkable instance of the cremaster muscle being completely under the influence of volition is recorded by Mr. Hutchinson.*\nDeep spermatic fascia. \u2014 The tunica vaginalis and spermatic cord are invested by a thin delicate fascia, which is situated beneath the cremaster muscle, and forms a common\n* Practical Observations in Surgery, second edit.\np. 186.\nfibrous envelope to the testicle, and spermatic cord. It is attached to the back part of the gland. This membrane may be traced as a prolongation of the fascia transversalis, and is probably formed in the process of transition of the testicle from the abdomen to the scrotum.\nThe spermatic cord. \u2014 The parts composing the spermatic cord, are the vas deferens, the artery of the duct, the spermatic artery and veins, the lymphatic vessels, and the spermatic nerves. These parts are connected by loose areolar tissue. A fibro-cellular process, being the remains of the process of serous membrane originally connecting the tunica vaginalis with the peritoneum, may sometimes be perceived in the front part of the cord. The spermatic cord extends from the internal abdominal ring to the back part of the testicle. Its upper portion, therefore, lies in the inguinal canal. The coverings of the cord are the same as those of the testicle : viz., the integuments, superficial fascia, cremaster muscle, and deep spermatic fascia.\nFor Comparative Anatomy, see the article Organs of Generation.\nAbnormal Anatomy of the Testicle.\u2014 Congenital imperfections and malformations.\u2014 Numerical excesses and defects. \u2014 Cases of supernumerary testicles are mentioned in the writings of the old authors, and persons have been described with four or five of them, accompanied with a proportionate increase in the venereal appetite. Nearly all these cases are of a fabulous character. Such must be remarked of the case of trevripx^y or nian with five testicles, mentioned by Schaarf*, and with that of a man with four testicles alluded to by Blegny.'j- Blasius, an old writer not unworthy of credit, has, however, given an account of the examination of a man, thirty years of age, and otherwise well formed, who had two testicles on the right side, of the same size and shape as that on the left, which is illustrated by a small engraved figure representing a distinct artery from the aorta, and vein from the vena cava proceeding to each of the two testicles on the right side.J This is the only case of supernumerary testicle recorded by the old authors, which has any semblance of authenticity. Neither Morgagni, Haller, nor Meckel met with a single example, and they questioned the existence of such a condition. Two cases have recently been recorded as examples of triple testicle, but they were not verified by examination after death. One is related by Bliimener, an army surgeon, in Rust\u2019s Magazin f\u00fcr die Gesammte Heilkunde for 182d: the other by Dr. Macann, a British surgeon. $ An epi-plocele, a fatty or fibrous tumour in the scrotum, or an encysted hydrocele of the cord,\n* Eph. Nat. Cur. Dec. 111. Ann. v. vi. Obs. 89. p. 175.\nf Zodiaque Fran\u00e7ais, Ann. 11. Most of the reputed cases of Triorchides are quoted by Arnaud, in his M\u00e9moires de Chirurgie. Mem. iii. part i.\nt Ger. Blasius, Obs. Med. Anat. Obs. 20. p. 60.\nI Provincial Medical Journal, Nov. 5.1842, p. 113.","page":986},{"file":"p0987.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\nmight readily be mistaken for an additional testicle. Morgagni mentions that he was once deceived by a portion of omentum. In the pathological collection at St. Thomas\u2019s Hospital is preserved the testicle of the eccentric Dr. Monsey, who appeared during life to be supplied with three of these glands. The supposed additional testicle consists of an indurated fibrous tumour attached apparently to the tunica vaginalis.\nMany instances of monorchides, or persons having only a single testicle are also mentioned by the old authors ; but as the data are very imperfect, and as little was known respecting the transition of the testicle at the time these cases were recorded, they must be viewed with great suspicion. They were most probably cases in which one of the glands was either retained within the abdomen, or, from some cause had been completely atrophied. I know no satisfactory reason why a deficiency of one or both testicles should not occasionally occur without any other malformation ; but they are anomalies of which there are few authentic examples in the annals of medical science. Mr. Paget has published the particulars of a case in which he believes one testicle was deficient at birth.* * * \u00a7 No account of the man is attached to the particulars of the dissection, and it is open to question whether the deficiency of the gland was not the result of atrophy. Dr. Fisher, of Boston f, has recorded a more satisfactory example of absence of both testicles. The de j ficiency was remarked from birth, and the subject of the malformation was regarded as a natural eunuch, and died at the age of forty-five.\nMr. Thurnham has published an account of the dissection of an infant who died at the age of four months. In addition to an atrophied condition of the right kidney, and a remarkable malformation of the ureters, it was found that neither of the testicles had descended. The right lay in the abdominal cavity, just above the inguinal canal. On the left side no testicle would appear to have been formed; the spermatic vessels on this side terminated in a little mass of fat ; the vas deferens, however, was present, and was apparently as well developed as that of the perfect testicle. J A case of monstrosity is related by Dr. Friese in Casper\u2019s Wochenschrift. \u00a7 The child lived only half an hour: in addition to the absence of the external genital organs, there were neither testes, vasa deferentia, nor vesicul\u00e6 s\u00e9minales. Cases, however, in which the whole of the genital apparatus is deficient or irregularly formed, do not come within the scope of this article. Geoffroy St. Hilaire has recorded a remarkable, and so far as I know, unique case of union of the testicles in the abdomen. |[\n* London Medical Gazette, vol. xxviii. p. 817.\nf American Journal of the American Sciences, vol. xxiii. p. 352.\nX London Medical Gazette, vol. xx. p. 717.\n\u00a7 Dec. 25. 1841. Quoted in the British and Foreign Medical Review for April 1842, p. 527.\n|| Hist, des Anomal, de l\u2019Organ. t. i. p. 542.\n987\nDeficiencies and imperfections of the vas deferens. \u2014 In Mr. Paget\u2019s case of supposed absence of the testicle it is stated, that the vas deferens terminated nearly opposite the external ring in a rounded cul-de-sac; and in Dr. Fisher\u2019s case of deficiency of both testicles, that the vasa deferentia, though properly formed and nearly of natural size, terminated in cul-de-sacs at the end of the cord. In the museum of St. Bartholomew\u2019s Hospital, there is a preparation taken from a man fifty years of age, who died of strangulated hernia. A piece of intestine was strictured by a band of adhesion connected with the mesentery, and the testicle was detained in the upper opening of the ring. On dissection of the parts, the vas deferens was found to terminate near the testicle in a cul-de-sac. The gland was very small, and its structure appeared granular like the undeveloped testicle of a youth. There was no trace of the epididymis. Mr. Hunter in dissecting a male subject found the vasa deferentia not only deficient near the testicles, but terminating below in a single irregularly formed vesicula seminalis, and having no communication with the urethra.* There are a few other cases on record, in which the vas deferens has been defective at the extremity which joins the ejaculatory canal. Thus, Tenon, in the dissection of an infant affected with extraversion of the bladder, found that the vasa deferentia terminated separately at the bottom of the pelvis, in two white tubercles : the scrotum, testes, and vesicul\u00e6 s\u00e9minales were in a natural state, f But besides these imperfections at its two extremities, this duct has been found wanting throughout nearly its whole extent. Brugnoni mentions, that in dissecting the parts of generation in a robust man, from twenty-six to twenty-seven years of age, he found the right epididymis almost entirely absent, the only part remaining being the head, which formed nodules filled with semen. The rest of the epididymis and the vas deferens were wanting, without any mark of disease. The testicle was perfectly sound, and nearly of the same size as the left one. On examining the corresponding vesicula seminalis he found at its anterior extremity a portion of the canal of the vas deferens about an inch in length, and properly formed. The vesicula seminalis itself was flaccid and quite empty ; whilst the left was full of semen. He remarks, that although this vicious conformation was according to all appearances congenital, nevertheless the vesicula seminalis and ejaculatory canal had preserved their natural cavities. J In a case related by Bosscha, the left vas deferens of a robust man terminated in a blind extremity near the testicle, the rest of the canal being wanting. There was the rudiment of a left vesicula seminalis in the\n* Works by Palmer, vol iv. p. 23.\nt Mem sur quelques Vices des Voies Urinaires, &c. n M\u00e9m. de l\u2019Acad. Roy. des Sciences \u00e0 Paris, 1761, p. 115.\nX Observ. Anat. sur les V\u00e9sicules S\u00e9minales. Mem de l\u2019Acad. Roy. des Sciences \u00e0 Turin, 1786, and 1787, p. 625.","page":987},{"file":"p0988.txt","language":"en","ocr_en":"988\nTESTICLE (ABNORMAL ANATOMY).\nform of a blindly-ending canal running tortuously in the shape of the letter S. The left testicle was sound.*\nMr. Paget has happily explained the origin of these several defects in the vas deferens, by reference to the mode of development of the special organs of generation. He observes+, after M\u00fcller and Valentin, that, in the normal course of human development the proper genital organs are in either sex developed in two distinct pieces : namely, the part for the formation of the generative substance, the testicle or ovary, and the part for the conveyance of that substance out of the body, the seminal duct or ovi-duct. The testicle or ovary as the case may be, (and in their earliest periods they cannot be distinguished), is formed on the inner concave side of the corpus Wolffianum, and the seminal or ovi-duct, which is originally an isolated tube closed at both extremities, passes along the outer border of that body from the level of the formative organ above to the cloaca or common sinus of the urinary, genital, and digestive systems below. The perfection of development is attained only by the conducting tube acquiring its just connections at once with the formative organ, and, through the medium of the cloaca, with the exterior of the body. The sexual character is first established, when, in the male, the formative and conducting organs become connected by the development of intermediate tubes which constitute the epididymis ; or when in the female, a simple aperture is formed at the upper extremity of the conducting tube, and is placed closely adjacent to the formative organ. In both sexes alike, the lower extremities of the conducting tubes first open into the common cloaca, and subsequently, when that cavity is partitioned into bladder and rectum, or bladder, vagina, and rectum, they acquire in each their just connections, and become in the male the perfect vasa deferentia, and in the female the Fallopian tubes and uterus.\nThe inquiry is not without interest, what influence have these deficiencies and imperfections in the vas deferens on the evolution and subsequent condition of the testicle ? In the case of the adult which occurred at St. Bartholomew\u2019s Hospital, the testicle was small, and its structure appeared granular, like the undeveloped testicle of a youth, but as it had not descended into the scrotum, and was combined with hernia, there may have been other causes impeding its due evolution. In Mr. Hunter\u2019s case, the testicles which were in the scrotum were very sound. In the case of the man related by Brugnone, the testicle on the side corresponding to the defective vas deferens was perfectly sound, and nearly of the same size as the other. So also in Bosscha\u2019s case, it is stated, that the testicle was sound. Although either of these defects in the vas deferens renders the gland an useless organ,\n* Diss. sistens Obs. de vesicul\u00e6 seminalis sinis-tr\u00e6 defeetu, integris testibus, vase vero deferente clauso, quoted by Dr. Vrolik, Handboekder Ontleed-kundige Ziektekunde, 1st Deel. p. 210.\nj- Loc. cit. p. 818.\nand if it occurred on both sides of the body, would necessarily cause impotency, these cases, nevertheless, tend to shew that the absence or imperfection of the excretory duct does not prevent the development of the testicle at the proper period, and has no direct influence in causing it to waste ; and these inferences are fully confirmed by experiments on animals, performed by Sir A. Cooper and by myself.* These cases and experiments show, then, that the testicles maybe properly developed, though a physical obstacle to the elimination of their secretion is present from birth ; and that so long as the testicles exist entire, though to no purpose, the individual acquires and preserves all the marks of the male sex ; the secretory organ alone appearing to be that upon which the sexual characters depend. The engorgement of the seminal ducts with sperm is liable, it is true, to cause inflammation of the testicle, which may end in atrophy, but this is only a secondary and occasional effect of the interruption in the excretory duct.\nImperfect transition. \u2014 It occasionally happens that at birth one or both testicles have .not passed into the scrotum, being detained either in the abdomen near the groin, in the inguinal canal, or in the groin, just outside the external ring. In a table of one hundred and three male infants, examined by Wrisberg at the time of birth, it appears that seventy-three had both testicles in the scrotum ; in twenty-one, one or both were in the groin. Of these, five had both, seven the right, and nine the left in the groin ; in twelve, four had both, three the right, five the left, only in the abdomen, j-According to this table, the imperfection occurs rather more frequently on the left side than on the right, in the proportion of seven to five. In twenty-five cases examined at different ages, varying from five to sixty,-\u2014sixteen of which came under my own observation, the remainder being taken from the recorded experience of others, \u2014 in thirteen the imperfection was on the right side, and in twelve on the left. Dr. Marshall states, that in the examination of 10,800 recruits, he had found five in whom the right, and six in whom the left testicle was not apparent. In two of these cases there was inguinal hernia on the side where the testicle had not descended. J He met with but one instance in which both testicles had not appeared, \u00ff The testicle sometimes remains permanently fixed in the situation in which it is placed at birth || ; but in some instances the passage, though delayed, is completed at some period previous to puberty, and often within a few weeks after birth. Mr. Hunter was of opinion that this completion most frequently\n* Yide Sir A. Cooper on Anatomy of tlie Testis, p. 51., and my Treatise on the Diseases of the Testis, p. 64, and seq.\nf Commentatio Soc. Beg. Scient. Goetting. 1778.\nj Hints to Young Medical Officers in the Army, p. 83.\n\u00a7 Ibid. p. 207.\n1| Persons whose testicles had not made their appearance were called *pu^>\u00e9px\u2018^f, or testicondi, by the ancients.","page":988},{"file":"p0989.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t989\nhappens between the years of two and ten.* Of the twelve cases mentioned by Wrisberg, in which one or both testicles were retained in the abdomen, in one the descent took place the day of birth, in three on the day after, in three others on the third day, in two instances on the fifth day, and in one on the twenty-first day : in the other cases, the testicles had not appeared at the fourth or fifth week after parturition, f My own observations lead me to believe, that if the passage does not take place within a twelvemonth after birth, it is rarely fully and perfectly completed afterwards, without being accompanied with rupture. For the causes which operate at this late period tend as much to promote the formation of hernia as the transition of the testicle. In cases where the testicle makes no appearance before puberty, uneasiness is often experienced at that period, owing to the enlargement of the gland being restrained by the rings and parts composing the inguinal canal. At the same time also, it is often protruded outside the external ring by the movements of the abdomen in respiration.\nThe causes of a failure in the transition of the testicle have not been much investigated, and as considerable doubt has long prevailed respecting the mode and agency by which this change is effected, no satisfactory explanation could 'be expected of the circumstances interrupting or preventing it. When we reflect on the nature of that process, as my researches have led me to describe it, it is clear, that there must not only be a perfect adaptation of parts, a due relation between the body displaced and the structures which it traverses, but also corresponding power in the agent by which it is accomplished. There are few muscles in the human body whose development in different individuals varies in a greater degree than that of the cremaster. And if such be the case after birth, it is not unreasonable to presume that similar differences exist in the foetus before the gland changes its position, and that a failure in the process may be the result of deficient power in the musculus testis to accomplish the passage. It is not improbable that this muscle is sometimes paralysed, and that the faulty transition is owing to a want of a due supply of the nervous energy, which we know is often denied to other muscles during foetal existence, and is the cause of deformities in the feet and other parts, with which infants are often ushered into the world. I think, indeed, we may fairly enumerate paralysis and defective development of the cremaster amongst the presumed causes of the imperfect transition of the testicle. Peritonitis occasionally attacks the foetus in utero J, and produces adhesions between the various abdominal viscera. It is well known that in congenital hernia the testicle is frequently united to a portion of\n* Lib. cit. p. 15.\nf Lib. cit. p. 203.\ni Vide Contributions to Intra-uterine Pathology, by Dr. Simpson, Edinb. Med. and Surg. Journal, nos. cxxxvii. and cxl.\nintestine or omentum, and that the formation of these adhesions previous to the transition of the testicle is sometimes the cause of the displacement, the viscera being drawn, together with the gland, into the scrotum. Many facts seem to show that similar adhesions are, on the other hand, an occasional cause of the temporary and permanent retention of the testicle, the cremaster being insufficient to overcome this obstacle to its passage.\nIn the examination of a man, age sixty, I found the right testicle just external to the abdominal ring ; it was small in size, and closely adherent to a portion of omentum. A young man was under my care for many months, on account of an imperfect transition of the testicle on the left side. The gland moved backwards and forwards through the external abdominal ring. By pressure above, it could be forced down sufficiently to admit of being examined. This testicle was much smaller than the right, which was in the scrotum, and I could distinctly make out a portion of intestine closely adherent, which accompanied the organ in all its movements. It is probable that the smallness of the opening in the internal abdominal ring is sometimes a cause of the detention of the testicle, especially in those cases in which the organ is retained within the inguinal canal. Mr. Wilson, an accurate anatomist, was of this opinion*, which is supported by the fact, that the testicle is oftener found in the groin than in the cavity of the abdomen. M. Dela-siauve mentions a case, in which, he states, the organ was retained by the border of the outer column of the ring.f Mr. Hunter was inclined to suspect that the fault originates in the testicles themselves. It is difficult to understand how this can be, for as the gland is passive in this process, it can offer no obstacle, unless it grows too large to pass the opening in the abdominal parietes ; whereas, it is admitted that the gland when retained is usually below the natural size. Nor does it appear, that the interruption is owing to any want of proper length in the vas deferens, for in a case of imperfect transition in a boy, whose body I examined, I particularly noticed that this duct was so long as to be doubled on itself, and tortuous, a circumstance which has been remarked in other cases by Mr. Mayo J, Rosen-merhel\u00ff, and others. It may be concluded then, that the causes of a failure in the passage of the testicle are various ; that this imperfection may result from want of power, or paralysis of the cremaster muscle; from adhesions retaining the gland within the abdomen ; and from a contracted state of the opening of the external abdominal ring.\nMr. Hunter states, that when one or both testicles remain through life in the belly, he believes that they are exceedingly imperfect,\n* Lectures on the Urinary and Genital Organs, p. 405.\nf Revue Medicale, Mars, 1840, p. 363.\ni Human Physiology, 3d edit. p. 411.\n\u00a7 Ueber die Radicalcur des in der Weiche liegenden Testikels.","page":989},{"file":"p0990.txt","language":"en","ocr_en":"990\tTESTICLE (ABNORMAL ANATOMY).\nand probably incapable of performing their natural functions ; and that this imperfection prevents the disposition for descent taking place. That they are more defective even than those which are late in passing to the scrotum, he infers from the circumstance, that in quadrupeds, the testicle that has reached the scrotum is considerably larger than the one which remains in the abdomen. Mr. Hunter had seen only one case in the human subject where both testicles continued in the abdomen, but this proved an exception to the above observation, since we are led to conclude that they were perfectly formed, as the person had all the powers and passions of a man.* Professor Owen in commenting upon these observations, states, \u201c It seems remarkable that with this experience Mr. Hunter should have formed from inconclusive analogy, and promulgated, an opinion tending to occasion so much unhappiness as that which attributes exceeding imperfection and probable incapacity of performing their natural functions to testes which in the human subject are retained within the abdomen. That there is nothing in such a situation which necessarily tends to impair their efficiency is evident, from the number of animals in which they constantly form part of the abdominal viscera; and in those in which the testes naturally pass into a scrotum, their continuance in the abdomen, ^according to our author\u2019s own observation, is accompanied only with a difference of size or shape ; now we may readily suppose that this may influence the quantity, but not necessarily the quality, of the secretion.\u201d There are very few accounts on record of the dissection of undescended testicles. In a case, in which M. Cloquet found the left testicle situated within the abdomen, the gland was well formed, and of the same size as the right, which had descended into the scrotum. The parts taken from an apprentice of Sir A. Cooper, who unfortunately committed suicide in consequence of the infirmity, are preserved in the Museum of Guy\u2019s Hospital. I have examined the preparation ; and the testicles, which are both within the abdomen, close to the internal ring, appear to be nearly, if not quite, the natural size, and it is stated that the ducts contained semen. In a lad, aged nineteen, whose left testicle was found, by Dr. Bright, within the abdomen, near the brim of the pelvis, the gland was considerably smaller than natural, but the ducts and secreting structure were quite perfect.f These are the only cases of testicles situated within the abdomen in which we have any account of the anatomical condition of the gland. In addition to the evidence they afford of the capability of testicles thus placed to exercise their functions, may be adduced the case of Mr. Hunter, just alluded to, in which a person, both of whose testicles continued in the abdomen, had all the powers and passions of\n* Works by Palmer, vol. iv. p. 18.\nf Hospital Reports, vol. ii. p. 258.\na man ; and a case recorded by Mr. Poland, of a man so formed, who was aged twenty-nine. He had all the signs of virility, had married twice, and was the father of two children.* On the other hand, Mr. Wilson mentions the case of a young man, twenty-five years of age, whose testicles never descended. He had some beard, and not an unmanly appearance ; but although an imprudent, and in some things a dissipated person, he had never shown the least desire for women, or disposition for sexual intercourse.f John West, a lad, aged sixteen, died in the London Hospital, in a state of universal anasarca. There was no appearance of beard, and only a few hairs were scattered over the pubes. My attention was particularly directed to the state of the genital organs, by observing that the scrotum, which was greatly distended with serous effusion, was not fully developed on the right side. I found the right testicle within the abdomen, about an inch and a half above the internal ring. It was very small, not larger than that of a child two years of age ; and on cutting into it, the gland presented the granular appearance usually remarked at that early period.\nPassage of the Testicle into the Perineum. \u2014 Mr. Hunter first observed that the testicle in changing its situation does not always preserve a proper course towards the scrotum, there being instances of its taking another direction and passing into the perineum. How this is brought about, he remarks, it is difficult to say ; it may possibly be occasioned by something unusual in the construction of the scrotum, or more probably, by a peculiarity in that of the perineum itself. For it is not easy to imagine how the testicle could make its way to the parts about the perineum, if these were in a perfectly natural state. He met with two instances of this imperfection. Many years ago a little boy, one of whose testicles had thus deviated from its proper course was brought to the London Hospital. The gland was lodged in the perineum at the root of the scrotum. M. Ricord met with this singular anomaly in two instances. M. Vidal (de Cassis) observed it in two brothers : their father was exempt from it. The testicle abnormally placed was smaller than the other. J The irregularity is exceedingly rare, and the above cases are all with which I am acquainted.\nPassage of the Testicle through the Crural Ring. \u2014 M. Vidal relates the case of a man, one of whose testicles, instead of passing out of the abdomen at the inguinal canal, made its exit at the crural ring. The organ was mounted upon the abdomen like a crural hernia. A portion of intestine traversed the inguinal canal, forming a rupture on that side. \u00a7 I know of only one other instance of this\n* Guy\u2019s Hospital Reports. Second series, vol. i. pp. 162, 163.\nj- Lectures on the Urinary and Genital Organs, p. 408.\n\u00ee Trait\u00e9 de Pathologie externe, t. v. p. 432. 2eme, edit.\n\u00a7 Ibid p. 431.","page":990},{"file":"p0991.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\nanomaly, which is reported by Eckardt. In this ease, the testicle passed out at first through the inguinal canal, but having been returned by the patient into the abdomen, it subsequently escaped at the femoral ring.*\nInversion of the Testicle. \u2014 It sometimes happens that the position of the testicle in the scrotum is reversed, so that the free surface presents posteriorly, and the epididymis is attached to the anterior part of the gland, instead of to the posterior. The first case that I met with was that of a man who had a swelling of the right testicle, which puzzled his medical attendant. On examination 1 found this to be the epididymis thickened from chronic inflammation. I was able clearly to trace the vas deferens proceeding to it along the front of the scrotum. The body of the testicle was unaffected, and its posterior edge was quite smooth and regular. The disposition of the left testicle was normal. On visiting the H\u00f4pital de Midi in Paris, in April, 1849, M. Ricord showed me a case of epididymitis on the left side, in which the gland was thus inverted. He informed me that he had often met with this arrangement. I have since had two patients under my care, one of whose testicles was thus inverted. One was a lad in the London Hospital affected with epididymitis. The other was a gentleman who consulted me for chronic orchitis confined to the body of the testicle. The epididymis being unaffected, the inversion was less perceptible than in the three preceding cases. M. Maissonneuve, in a thesis published in Paris in 1835, I believe first called attention to this irregular disposition, which he states that he had met with many times upon the dead body, and upon the living, and he mentions what I remarked myself in the four cases just noticed, that the inversion was confined to one side. Surgeons should bear in mind the liability to^this disposition of the gland in making their diagnosis of the diseases affecting it.\nAtrophy of the Testicle. \u2014 The testicles, like other organs formed for the exercise of temporary functions, do not arrive at a perfect state of development until a certain period of life, after which their activity ceases, and they become gradually and imperceptibly diminished. Thus we find that in early life they are small in proportion to the size of the body as compared with their condition at puberty, and that as old age advances and the generative functions cease to be called into action, they undergo a diminution in size, their vessels grow less, the seminiferous tubes become small and contracted, and partially obliterated. In the lower animals these changes are far more remarkable than in man, for as the functions of the testicle are exerted only at stated periods of the year, as the rutting or copulating season advances these organs rapidly increase in bulk, and in its decline undergo a proportionate degree of wasting. In man, it sometimes happens that the tes-\n* Loder\u2019s Journal f\u00fcr die Chirurg, ii. Bd. 1 Stff. s. 187.\n991\ntides do not acquire their proper size at the usual period, their development being from some cause or other arrested ; and also, after the organs have arrived at their full and perfect growth, that occasionally one or both suffer a premature decay. Under the head then of Atrophy of the Testicle I shall consider : 1. Arrest of Development ; and 2. Wasting.\nArrest of Development. \u2022\u2014 If the congenital lesions to which the testicle is liable had not been previously treated of, the cases of absence of the organ already described, might be correctly referred to the present head, as the deficiency in these cases was no doubt the result of an arrest in the early development of the organ. But the cases that 1 am now about to consider are those in which the subsequent evolution which the testicles undergo at puberty is delayed beyond the usual period, or never takes place at all. Mr. Wilson relates a curious instance of his having been consulted by a gentleman, twenty-six years of age, on the propriety of entering the marriage state, whose penis and testicles very little exceeded in size those of a boy of eight years of age. He had never felt the desire for sexual intercourse until he became acquainted with his intended wife ; since that period he had experienced repeated erections, attended with nocturnal emissions. He married, became the father of a family ; and these parts, which at six and twenty years of age were so much smaller than usual, at twenty-eight had increased nearly to the usual size of those of an adult man.* Mr. Wilson mentions this singular case, as it will admit of questions whether the parts alluded to became properly formed as to size, and possessed of the power of secretion, in consequence of being, although so late in life, influenced by the passions excited by attachment to a particular female ; or whether the enlargement and proper action of the parts beginning, occasioned such passion first to exist. He thinks the probability in favour of the former supposition, in which opinion I certainly concur. Lallemand mentions having seen a man about thirty years of age, extremely fat, and without a beard or hair on the pubes, whose penis and testicle appeared to belong to a child of from seven to eight years : he had never experienced erections or venereal desires.f A young man died in the London Hospital of disease of the heart. He was seventeen years and nine months old : the body measured five feet five inches in height, and was plump and well formed. There was no appearance of beard, or whiskers, or of hair on the pubes. The penis and testicles were very small, not larger than they are usually found in boys of three or four years of age. The testicles were about equal in size, and one of them weighed only two scruples and one grain. Both organs were normal in structure, appearing like the glands in early life, when the tubular structure\n* Lectures on the Urinary and Genital Organs, p. 424.\nt Des Pertes S\u00e9minales Involontaires, t. ii. p. 380.","page":991},{"file":"p0992.txt","language":"en","ocr_en":"992\tTESTICLE (ABNORMAL ANATOMY).\nis very indistinctly developed. No spermatozoa could be detected. These were clearly instances of arrest of development of the testicles. As these organs are chiefly excited to action by an operation of the mind, it is easy to understand that they may sometimes remain undeveloped owing to defective organisation of the brain, an absence of sexual desires being invariably remarked in these cases. Cases of wasting of the testicles after injuries of the head, and the frequent absence of the venereal appetite in cretins and idiots, tend to strengthen this opinion. The following are marked examples of defective development of the sexual organs, accompanied with imperfection of the brain. An idiot, aged nineteen, subject to epileptic fits, died of typhus fever in the Hackney union. The youth was of short stature, and the form of the body was not indicative of either sex, but the contour was rounded as in the female. There was no appearance of hair about the face or pubes. The abdomen and other parts were covered with a thick layer of fat. The penis and scrotum were remarkably small, not larger than they are usually found in a child two or three years of age. Both testicles were in the scrotum, but they were of very diminutive size ; the right weighed less than a drachm, and the left not more than twenty three grains. The right gland had descended a very little way below the abdominal ring. The glandular structure and epididymis of both testicles were indistinct, and the vasa deferentia also extremely small. Nothing remarkable was observed in the structure of the brain. Mr. Hovell, the surgeon of the union, also showed me another inmate of the same workhouse, a lad aged nineteen, and of weak mind, whose penis and testicles did not exceed in size those of a boy seven or eight years of age, and who had only a few scattered hairs on the pubes. In the museum at Fort Pitt, Chatham, are preserved two undeveloped testicles about the size of those of a child six months old, but healthy in structure, which were taken from a lunatic 58 years of age. His penis was small and he had never experienced any inclination for sexual intercourse.\nWanting. \u2014 In investigating the alterations in the nutritive condition of the testicle, it is very desirable to fix, if possible, some standard by which they may be estimated. The size of the gland is neither uniform nor conveniently appreciated. Its weight, likewise, varies so much in different persons and in the same individual at different periods, according as it has lately exercised its functions or remained inactive, and as it is full of semen or empty, that it is scarcely possible to determine on any accurate standard of this kind. (See p. 976.)\nI should consider the testicle of an adult weighing less than three drachms as in a state of atrophy. A testicle in an advaced state of wasting, not arising from disease of the gland, usually preserves its shape, but feels soft, having lost its elasticity and firm-\nness. Its texture is pale and exhibits few blood-vessels, the tubuli and septa dividing the lobes are indistinct, and the former cannot be so readily drawn out into shreds as before. The epididymis does not usually waste so soon nor in the same degree as the body of the testicle. It sometimes however, loses its characteristic appearance, and I have even found it reduced to a few fibrous threads. The fluid pressed out of the wasted testicle and epididymis is entirely destitute of spermatic granules and spermatozoa. In many instances adipose tissue is deposited behind the tunica vaginalis, and encroaches on the epididymis and posterior part of the testicle. Fatty matter is also found in the glandular substance of atrophied testicles, as in one taken from a man aged forty-six, who died of dropy consequent on disease of the kidneys, which was wasted to one fifth its natural size. In addition to the presence of adipose tissue beneath the visceral portion of the tunica vaginalis, I recognised a quantity of yellow matter irregularly disposed amongst the wasted tubuli. This matter on examination in the microscope, proved to be oil globules, and readily dissolved on the application of ether. The structures composing the spermatic cord undergo a corresponding diminution ; the cremaster muscle disappears, the nerves shrink, and the vessels are reduced in size and number. The vas deferens, though small, can generally be injected with mercury as far as the commencement of the epididymis. A testicle, atrophied from disease, is not only of diminished size and weight, but is altered in shape, being uneven and irregular, and sometimes of an elongated form. The surfaces of the tunica vaginalis are adherent and its cavity is partly or entirely obliterated. There is no, or very little, trace of the proper glandular structure, the organ being converted into fibrous tissue of a firm texture. It loses its peculiar sensibility to pressure, but is sometimes the seat of morbid sensibility.\nAll those causes which produce decay in other parts likewise occasion wasting of the testicle. Thus an impeded circulation, pressure, want of exercise, and loss of nervous influence, have been noticed as causes of atrophy of this gland. To these must be added certain causes which specially affect the testicle. The following case, related by Mr. Wardrop, is a good example of atrophy from defective nutrition. A person, both of whose testicles were completely absorbed, nothing being felt in the scrotum but a loose vaginal coat, died of an aneurism of the aorta, formed at the origin of the spermatic arteries, both of which were obliterated.* A ligature on the spermatic artery is sufficient to cause a total decay of the testicle, which induced the celebrated Harvey f to propose its ap-\n* Note to his edition of Baillie\u2019s works, vol. ii. p. 315.\nf Anatomical Exercitations concerning the Generation of Living Creatures. Lond. 1653, pp. 113,114.","page":992},{"file":"p0993.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t993\nplication for the removal of a certain form of sarcocele ; a suggestion, the credit of which has been improperly assumed in recent years by C. J. Maunoir, of Geneva. The influence of pressure in causing partial atrophy of the testicle, is somtimes remarked in old cases of hydrocele and h\u0153matocele, in which the gland has been long subjected to compression from the retained fluid.\nIt has been said that the testicles waste in those persons who strictly adhere to their monastic vows, but I am not aware that there is sufficient authority for this remark. In persons who marry, after many years of ab' stinence from sexual intercourse, the testicles undergo a certain degree of enlargement. It is a great error to suppose that sexual connection in early life is essentialfor the preservation of these organs. In cases of enlargement of the prostate the ejaculatory canals sometimes become completely obstructed. Under these circumstances, the semen secreted under excitement having no means of escape, encumbers the testicles for a time, but afterwards becomes absorbed, and it is said that atrophy of these glands sometimes follows ; but I have never observed any instance of wasting of the organs from this cause. As examples of atrophy of the testicles from loss of nervous influence, may be adduced cases of paraplegia, in which these organs have been known to waste. Portal mentions the case of a robust man, aged thirty-five, who was attacked with painter\u2019s colic, attended with great debility of the lower extremities. The testicles diminished considerably ; and although he afterwards recovered from the paralysis of his limbs, these glands always remained wasted ; and the man was incapable of the act of generation.* In the xxth volume of the \u201c Medical and Physical Journal,\u201d there is an account of a case of recovery after fracture, with partial dislocation of the first and second lumbar vertebrae, followed by paraplegia, in which, three years afterwards, the testicles were found entirely obliterated. It has been stated that the testicles sometimes waste from injuries, or from compression of the spine at the origin of the spermatic nerves. In a man who had received a blow on the lumbar region, the testicles gradually wasted away.j'\nThe most common cause of atrophy of the the testicle is the disturbance in its organisation consequent upon inflammation. As the inflammatory process ceases, the enlarged gland not only becomes reduced to its original size, but it sometimes slowly but steadily diminishes, till at length very little vestige of it remains Mr. Hunter has related three eases in which the testicle decayed in this way.J 1 have met with several instances of atrophy arising from this cause, and there are few surgeons of experience who have not witnessed cases of the kind. Wasting of the\n* Cours d\u2019Anatomie Medicale, t. v. p. 434.\nf Baillie\u2019s Works, by Wardrop, vol ii. p. 315.\nj Treatise on the Venereal Disease.\nVOL. IV.\ntesticle has been observed to occur after an attack of orchitis in mumps, arising as it is supposed from the translation of inflammation from the parotid to the testicle. Two cases oPcynanche parotidea in the adult, in which atrophy took place in the gland chiefly affected, are related by Dr. R. Hamilton.* I have witnessed one case, in which the patient attributed the loss of the gland to an attack of mumps in his infancy. Wasting is more liable to occur after inflammation of the body of the gland than after consecutive inflammation in which the epididymis is the part chiefly affected. One or both testicles have been found to waste in persons who have indulged too much in sexual intercourse or been addicted to onanism. Baron Larrey met with several cases of atrophy from excessive venery and abuse of strong drinks amongst the soldiers of the Imperial Guard.f Sir B. Brodie has recorded two cases in which wasting was occasioned by over-excitement ; in one from onanism, in the other from sexual intercourse. J I have also witnessed an instance of total atrophy of the left testicle in a person addicted to excessive masturbation. In this case, and probably in the others just quoted, the wasting was preceded by an attack of inflammation induced by inordinate excitement.\nIt is a common belief that wasting of the testicle is liable to be induced by the long-continued use of iodine. I have not met with any instance of it, and there are few cases in which the evidence is such as to render it at all clear that the decay of the gland was really occasioned by the remedy. M. Cullerier has published the case of a young man who took from twenty-five to thirty drops of the tincture of iodine for a period of three months for the cure of an obstinate gonorrh\u00e6a. This was followed by a state of impotency and partial wasting of the testicles, which lasted a twelvemonth, and the organs never regained their former size and vigour. M. Cullerier mentions another case of temporary loss of virile power occurring from the use of the iodine of iron.\u00ff I feel convinced, however, that if iodine produces wasting of the testicle at all, it does so so rarely, that the liability cannot be regarded as any objection to the free and long-continued use of this valuable remedy. Atrophy of the testicle has been remarked in elephantiasis of the Greeks, a disease in which tubercles are developed in various parts of the skin. Dr. Adams, in an account of the cases of that disease observed in Maderia, states that all those who were attacked with it before the age of puberty never acquired the distinguishing marks of that change in the constitution, and their testicles diminished in size, and that in those affected later in life the testicles became\n* Philos. Trans. Edinb. vol. ii. art. ix. p. 59. f M\u00e9moires de Chirurgie Militaires, vol. ii. p. 66. j London Medical and Physical Journal, vol. lvi. p. 297.\n\u00a7 M\u00e9moires de la Soci\u00e9t\u00e9 de Chirurgie de Paris, t. i.\n3 s","page":993},{"file":"p0994.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\n994\natrophied, and they lost the power of procreation.* * * \u00a7 Mr. Peacock also noticed a wasting of the testicles in several cases of elephantiasis in the Leper Hospital of Colombo, in Ceylon.^ A similar condition of these glands was remarked in a case of this disease, so rare in this country, narrated by Mr. Lawrence and also in another case at the London Hospital, which I recorded many years ago.\u00ff In a confirmed case however of this disease, in a boy aged thirteen, who was under my care in the year 1849, there was no diminution in the size of these glands. Wasting of the testicles is liable to occur after injuries of the head.\nSome years ago I saw a man who had met with an injury of this description, which had been followed by wasting of the testicles, and the development of tumours on each sideofthe chest, resembling mamm\u00e6. He was about fifty-nine years of age, a married man, and the father of several children. He had belonged to the legion in the Queen of Spain\u2019s service. About two years and a half previously, in an attempt to jump over a trench, he fell backwards and injured the posterior part of his head. Whilst on the ground he received a bayonet wound on the side, and a sabre cut on the forehead. He recovered from these injuries and returned to England. Since the accident he had completely lost his virility. He had no desire for sexual connection ; his penis had dwindled in size ; his right testicle had gradually wasted, and was no larger than a horse bean, and the left gland was also a good deal diminished in bulk. The skull at the occiput seemed somewhat flattened. Baron Larrey records the case of a man who was wounded in the back of the neck by a musket ball which grazed the inferior occipital protuberance. He recovered from the injury, but the testicles were reduced to a state of atrophy, and the penis shrunk and remained inactive. He also relates the case of a man of strong constitution and vigorous passions who received a sabre wound which cut off all the convex projecting part of the occipital bone, and exposed the dura mater. The patient lost the senses of sight and hearing on the right side, and his testicles sensibly diminished, and in fifteen days were reduced, especially the left, to the size of a bean.|| Lallemand had under his care a man thirty years of age, who, in the expedition to Algiers had received a sabre wound at the nape of the neck. His testicles were wasted, and venereal desire as well as erections had entirely ceased.T We cannot doubt that in these cases the loss of sexual desire, and the wasting of the testicles were the direct results of the injury to the brain, and they go far to prove the essential dependence of the functions of these glands\n* On Morbid Poisons, p. 265.\nf Edinb. Medical and Surgical Journal, vol. liii. p. 139.\nt Medico-Chirurgical Transactions, vol. vi. p, 214.\n\u00a7 Yide Medical Gazette, vol. vii. p. 447.\n|| M\u00e9moires de Chirurgie Militaire, p. 262.\n1 Pertes S\u00e9miuales Involontaires, t. ii. p. 41.\nupon the cerebral organ. The physiologist cannot fail to notice the rapidity with which the atrophy is stated in some of the cases to have succeeded the injury and the extent to which it proceeded. The withering of the testicles, was, indeed, so remarkable, that it can only be attributed to the sudden and complete extinction of the sexual instinct resident in the brain, and (if I may so express myself) to the immediate impression on the system of the future uselessness of these organs. In old age and in lingering diseases the decay of the testicles is extremely slow and gradual, and is never carried to the extent observed in cases of injury to the brain. In fact, men have survived the power or desire of performing the sexual act many years without the testicles being materially reduced in size. We have seen, too, that in the lower animals the testicles have been rendered useless by interrupting the vasa deferentia, without any such striking effect being produced on the glands as occurred in these cases of cerebral injury.\nInflammation of the tunica vaginalis, or acute hydrocele. \u2014 The inflammatory changes of the tunica vaginalis resemble those of the other serous membranes. M. Roux injected a hydrocele in a middle-aged man : inflammation was developed, but on the fourth day, gangrenous erysipelas attacked the scrotum, and caused the patient\u2019s death on the tenth day after the operation. On examining the tunica vaginalis, he found that it contained a large quantity of whitish serum, in the midst of which floated flakes of albumen ; other flakes of the same kind formed a thick coating over the testicle and internal surface of the membranous pouch. The serous membrane beneath appeared slightly thickened, and of a deep red colour. The epididymis and the lower part of the cord were swollen, and constituted the more solid part of the tumour produced by the inflammation. The body of the testicle was not increased in bulk, and it retained its natural consistence.* In the museum of the College of Surgeons, there is a beautifully injected preparation of hydrocele, showing the effects of inflammation after the application of the caustic. It is represented in the annexed wood-cut, which exhibits the sac with part of it cut away to show the swollen state of the epididymis, and the aperture made by the caustic (1); the tunica vaginalis is coated with flocculi of lymph. The sac of an inguinal hernia is seen above the hydrocele. The sound state of the body of the testicle, though surrounded by an inflamed serous tunic, whilst the epididymis partakes in the disease, has been accounted for by Gendrin. He says, when the sub-serous cellular tissue, which always participates in the inflammation of a serous membrane penetrates into the interior of an organ, it becomes a ready means of communicating\n* Journal G\u00e9n\u00e9ral de M\u00e9dicine, &c. t. lviii. p. 25. ; quoted from Gendrin, Histoire Anatomique des Inflammations, t. i. p. 143.","page":994},{"file":"p0995.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\nthe inflammatory action ; but when the contiguous organ or subjacent part is of a dif-\nFig. 638.\nferent structure from that of the cellular tissue, the extension of inflammation inwards is checked. Thus, in the case of the inflamed tunica vaginalis, the cellular tissue readily transmitted the morbid action to the epididymis, but the tunica albuginea arrested its progress to the body of the testicle ; and this explains the fact that after inflammation of the tunica vaginalis, excited by injection, the body of the gland is rarely found to suffer. On the other hand, the epididymis is seldom attacked with inflammation without the disease being quickly propagated to the tunica vaginalis.\nThe lymph effused in inflammation very often forms adhesions between the opposed serous surfaces, and these after some time are rendered very firm and dense, and in old cases are often converted into a fibro-cartilaginous structure. In a testicle which I examined some little while after an attack of acute inflammation, I found the lymph on both surfaces of the tunica vaginalis presenting a honeycomb or lace-like appearance, similar to that often met with on the pericardium. Inflammation, if violent, may end in the formation of pus ; suppuration is, however, a rare occurrence, unless artificially excited, for the cure of hydrocele. Inflammation of the tunica vaginalis is not only the most frequent disease of the testicle, but it is also one of the most common affections to which the body is liable.\n995\nIn the different disorders of the gland this membrane usually becomes inflamed at some period or other, and adhesions between its opposed surfaces are scarcely less common than those of the pleura. In examining the testicles of twenty-four adults, I found adhesions of greater or less extent in one or both glands in as many as nine instances.\nHydrocele of the tunica vaginalis. \u2014 The sac of the tunica vaginalis, like other serous cavities, is liable to dropsical effusion. The fluid effused is usually transparent, and of an amber, pale yellow, citron, or straw colour, and resembles the serum of the blood, but is occasionally thick. According to Dr. Marcet\u2019s analysis*, 1000 grains of this fluid of the specific gravity 1024*3 contained 80 grains of solid matter, of which 71*5 consisted of animal, and 8*5 of saline ingredients : hence it appears that this fluid only differs from the serum of the blood in possessing rather less animal matter. In an analysis of the fluid of hydrocele made by Dr. Bos-tockf, 100*00 parts of the specific gravity 1024 were found to contain\nWater\t-\t91*25\nAlbumen -\t-\t-\t6*85\nUncoagulable matter -\t1*1\nSalts\t-\t*8\n100*00\nA quantity of flakey matter or flocculent albumen is sometimes found floating in the fluid ; and it frequently contains, especially in old people, cholesterine in the form of a multitude of minute shining particles. The quantity of cholesterine contained in nineteen ounces of dark fluid full of these shining particles, which I removed from an old hydrocele, amounted to nine grains. In the examination of a testicle from a man of colour who died at an advanced age, I found the tunica vaginalis and its investing tissues very thick and firm, and the seat of cartilaginous and osseous deposits ; it contained about three drachms of a thick brownish substance, which was almost entirely composed of cholesterine. This was no doubt a very old case of hydrocele, in which, the more fluid parts having been absorbed, the cholesterine was left behind within the indurated sac. The quantity of serum which is suffered to accumulate varies considerably. In this country it seldom exceeds twenty ounces, though it has been known to amount to several pints. The largest quantity which I have met with is forty-eight ounces. Mr. Cline is said to have removed from Gibbon the historian as much as six quarts.J\nIn simple hydrocele the testicle is usually found at the posterior part, and rather below the centre, of the sac : its situation however is subject to variations. Before the occur-\n* Medico-Chirurg. Trans, vol. ii. p. 372.\nf Ibid. vol. iv. p. 72.\nI Sir A. Cooper\u2019s Lectures, by Tyrrell, vol. ii. p. 92.\n3 s 2","page":995},{"file":"p0996.txt","language":"en","ocr_en":"996\tTESTICLE (ABNORMAL ANATOMY).\nrence of hydrocele the tunica vaginalis may have been inflamed and contracted adhesions, so that the testicle may be connected to the membrane in front ; in which case the serum accumulates on each side of or above and below the organ. The position of the testicle in front may also be owing to an original inversion of the organ, in which the free surface presenting backwards, the fluid collects in that direction and presses the testicle to the front of the sac. Sometimes there are several adhesions producing a sacculated arrangement and forming what is termed a multilocular hydrocele. Occasionally the cysts thus formed have no communication with each other. In two instances I have seen a membranous partition in the sac of a hydrocele, separating it into two distinct cavities, formed by a layer of false membrane. There is one kind of sac or pouch often met with in hydroceles which is not commonly described. It is situated on the inner side of the testicle, but the opening into it is always found on the outer side between the body of the gland and the middle of the epididymis. This sac, which varies very much in size, is formed by the distention of the cul-de-sac which I have described as existing naturally at this part. Two examples of this kind of pouch are contained in the Hunterian Museum. One of them is represented in the accompanying figure. In large hydroceles\nFig. 639.\n1, aperture of the pouch between the body of the testicle and middle of the epididymis.\nthe epididymis is usually elongated and displaced ; and instead of a pouch being formed, the central part of the epididymis is drawn to some distance from the body of the testicle. In old hydroceles the sac is often a good deal thickened, the tissues enveloping it being condensed and converted into layers of dense fascia, such as are commonly observed\ninvesting only hernial sacs. The fibres, also, of the cremaster muscle, frequently become remarkably developed. This, however, is not constantly the case ; for in some instances of hydrocele of large size I have found this muscle atrophied. The thickened sac after many years acquires a cartilaginous character, and it sometimes even becomes ossified. In cases which have been frequently tapped, the sac is often found closely adherent to the skin of the scrotum at the various points perforated by the trocar. In the Hunterian Museum there is a preparation showing a long narrow band of adhesion passing from the anterior part of the testicle across the dilated sac of the tunica vaginalis to the membrane in front, which is supposed to have resulted from a wound of the testicle in the operation of tapping. In all large hydroceles the spermatic vessels are separated and displaced. The glandular structure of the testicle is sound, and the organ capable of exercising its functions. The disease is strictly confined to the investing serous tunic. The testicle is, however, frequently somewhat altered in shape, being flattened by the pressure of the confined fluid ; and in some instances has been found partially atrophied.\nHydrocele is generally single, but sometimes occurs on both sides. It is commonly said to form more frequently on the left side than on the right. During the last few years I have registered the new cases of hydrocele coming under my notice in public and private practice. Of one hundred and ten cases of simple hydrocele, one hundred and four were single, and six double. Of the former sixty-two occurred on the right side, and forty-two on the left. This result, which gives a decided predominance to the right side, does not agree with the observations of Velpeau, Gerdy, and Dujat, who found the disease to be more frequent on the left side. Hydrocele in young infants is usually single, and in my experience, more common on the right side. I have seen, however, a few cases of double hydrocele at this early period. When the fluid collected in the tunica vaginalis is attended with enlargement of the testicle, the swelling is termed a hydro-sarcocele. This affection is generally consequent on chronic orchitis, but it is occasioned by other morbid changes, malignant as well as innocent. In these cases the disease of the testicle is the original complaint and source of the irritation that excites an undue secretion from the tunica vaginalis.\nCongenital hydrocele. \u2014 In simple hydrocele, the original communication between the cavities of the peritoneum and of the tunica vaginalis is permanently obliterated; but it sometimes happens that fluid accumulates around the testicle in cases in which the obliteration has not been completed, constituting the variety termed congenital hydrocele. The opening of communication between the two cavities is usually small in size, about sufficient to admit a crow\u2019s or goose\u2019s quill. There is rather a rare variety of congenital","page":996},{"file":"p0997.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t997\nhydrocele, in which the testicle is retained in the abdomen or inguinal canal, while the peritoneum, prolonged for a short distance into the scrotum, forms the cyst containing the fluid which is covered only by the integuments and superficial fascia.\nEncysted hydrocele of the testicle. \u2014 In this form of hydrocele, fluid is effused into an adventitious cyst or cysts distinct from the sac of the tunica vaginalis. The cyst is composed of a thin delicate serous membrane, and may be developed in three situations : I. beneath the visceral portion of the tunica vaginalis investing the epididymis ; 2. between the testicular portion of the tunica vaginalis and the tunica albuginea, which are thus separated from each other ; 3. between the layers of the loose or reflected portion of the tunica vaginalis. The first is by far the most common situation, the two latter being very rare. These cysts are composed of a delicate serous membrane lined with tesselated epithelium, and the fluid contained in them differs from that of simple hydrocele in being perfectly limpid and colourless, and nearly free from albumen. In the cysts formed on the epididymis, the fluid, instead of being limpid, often presents an opaline opacity arising from the presence of spermatozoa.\n1. Small cysts not larger than a pea, and even smaller, may frequently be found beneath the serous membrane covering the head of the epididymis, in which they produce a slight depression. In several instances I have seen as many as five and six perfectly distinct cysts connected with this part.\nSometimes one or two small cysts are so embedded in the substance of the epididymis, that they cannot be recognised without dissection. Though these minute cysts generally contain a limpid fluid, I have sometimes found them filled with fluid of a milky hue, and I have even observed matter like pus tinged with blood. These accidental cysts sometimes project the tunica vaginalis before them until they become so far separated from the epididymis, where they were originally developed, as to be attached only by a narrow peduncle formed by a contraction of the connecting tunica vaginalis. Such is the mode of development of those small pendulous pedunculated cysts containing a limpid fluid often found hanging from the head of the epididymis, which were erroneously supposed by Morgagni to be hydatids. I have on many occasions observed them in the different stages of their production. Thus I have seen a pedunculated cyst attached at one part, whilst close to it there was a cyst of a similar nature embedded in the substance of the epididymis. In other instances I have found the cyst very prominent, but still connected by a broad attachment to the tunica vaginalis reflected over it, the membrane not having as yet contracted to form the narrow neck. In all these cases the prolongation of the tunica vaginalis investing the cyst could always be demonstrated by cautious dissection, and between the membrane and the cyst\nsome minute red bloodvessels were generally seen ramifying. These pednuculated cysts never acquire a large size : I have seldom found them to exceed that of a currant. From the exposed situation of the testicle they are liable to be ruptured, the vestiges of them consisting of fimbriated folds of membrane ; but this is not a common occurrence. I have seen the delicate peduncle by which the cyst was attached to the epididymis as long as three quarters of an inch. M. Gosselin states that small cysts are sometimes developed in the little appendage to the tunica vaginalis so often found connected with the upper part of the testicle.* This I have never seen.\nSo common are small cysts connected with the epididymis in the various states and stages I have described, that it is impossible to examine many testicles, especially of persons beyond the age of puberty, without finding them. According to M. Gosselin f, they are liable to be developed from the period of puberty to the age of thirty or thirty-five, but are rare at this period. After the age of forty they are very common, having been met with by him in at least two thirds of the testicles examined. Now when one or more of these cysts, instead of becoming pedunculated, enlarge so as to form a tumour in the scrotum\nFig. 640.\n* Archives G\u00e9n\u00e9rales des M\u00e9decine, 4e S\u00e9rie, t. xvi. p. 27.\nf M. Gosselin has given an elaborate account of the cysts connected with the epididymis, in two papers published in the 16th volume of the Archives G\u00e9n\u00e9rales de M\u00e9dicine. He makes two varieties of them, the small and large, and states that spermatozoa are found only in the latter. This distinction I consider to be unfounded, the smaller cysts being simply the early stage of the larger. M. Gosselin assumes the credit of being the first to describe the small cysts. They were, however, minutely described by me, and illustrated in my work on the Diseases of the Testis, published in 1843, of which M. Gosselin could scarcely have been ignorant, since he refers to my account of this form of hydrocele.\n3 s 3","page":997},{"file":"p0998.txt","language":"en","ocr_en":"998\tTESTICLE (ABNORMAL ANATOMY).\nthey constitute the form of hydrocele, called from its original seat, encysted hydrocele of the epididymis. I have observed this description of hydrocele in all its various modifications, from the enlargement simply of a single cyst to the complication occasioned by the varied development of several. As a cyst enlarges the epididymis becomes flattened, and displaced to one side, whilst the testicle is found either in front or at the bottom. It is sometimes at the side, but rarely at the posterior part of the swelling.\nIn the above woodcut (fig- 640.) of a specimen in the London Hospital Museum, the cyst is above the testicle, which is so displaced by it that its anterior edge is directed downwards. The tumour is generally of smaller size than a simple hydrocele, the fluid commonly not exceeding three or four ounces in quantity. I have, however, removed as much as thirty-two ounces from a single cyst. When the hydrocele is composed of several cysts, they are seldom of large size, but form a cluster more or less complicated and irregular, according to their size and number.\nA curious sacculated arrangement produced by the development of numerous contiguous cysts may be seen in the annexed figure, (fig. 641.) taken from a preparation dissected by\nFig. 641.\nmyself : part of the walls of the cysts are cut away to exhibit their interiors. The cysts are liable to inflammation, which causes more or less alteration in the quality and appearance of the fluid contained in them. The fluid may become albuminous and assume the straw or amber colour of ordinary hydrocele; and the cyst may contain lymph, form adhesions, or be lined with a false membrane, the fluid being thick and turbid. The cysts sometimes also become filled with blood, constituting a variety of h\u00e6matocele.\n2. A cyst may form between the tunica albuginea and the visceral layer of the tunica vaginalis, separating the two membranes which\nare naturally closely adherent to each other. This is a very rare form of hydrocele. A specimen which I discovered accidentally in dissection, is represented in the annexed wood-cut. (fig. 642.) The cyst contained about two\nFig. 642.\ndrachms of fluid, and is situated along the front of the testicle; it is a little thickened. A section of it is preserved in the Hunterian Museum. Sir B. Brodie has described a very similar specimen.* In the museum of St. Thomas\u2019s Hospital there is a specimen of a small cyst apparently developed from the epididymis : in its subsequent growth it had extended on the fore-part of the testicle, separating the tunica vaginalis from the tunica albuginea. t 3. In examining a healthy testicle I once found six or seven small cysts about the size of currants, studding the surface of the loose portion of the tunica vaginalis. Two of them were situated in a part of the membrane extending up the cord. They projected internally, and contained a limpid fluid. I have twice since seen a similar kind of cyst in the same portion of the tunica vaginalis. Similar adventitious cysts have also been observed on the internal surface of the sac of a simple hydrocele, and a preparation of the kind is contained in the Hunterian Museum. If a cyst developed in this membrane were to increase to any size, it would constitute a swelling which might be appropriately termed an encysted hydrocole of the tunica vaginalis.\nA circumstance of much interest in connection with encysted hydrocele of the testicle, is the occurrence of spermotozoa in the fluid contents of the cyst, a discovery made by the late Mr. Liston in 1843. During the last six years I have met with them in as many as twenty cases of encysted hydrocele : indeed, in the majority of instances in which\n* Lond. Med. and Phys. Journal, vol. lvi. p. 522.","page":998},{"file":"p0999.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t999\nI have searched for them. They were found in subjects of various ages from 30 to 75, and in cysts of all sizes from that of a filbert to the largest which the hydrocele attains. The fluid in some instances contained these bodies in remarkable abundance ; in others they existed sparingly. When very numerous, they give to the fluid an opaline opacity, or an appearance resembling cocoa-nut milk which is so characteristic as to enable the surgeon to predicate their presence from the appearance of the fluid alone without minute examination. If the fluid be allowed to remain at rest in a glass vessel, the spermatozoa subside to the bottom, rendering the lower portion more opaque than the upper. The fluid also exhibits slight traces of albumen, when tested in the usual way, which is not the case with the ordinary pellucid colourless fluid of encysted hydrocele. The spermatozoa were often as lively as in fresh semen. They were observed more frequently in the larger cysts than in the smaller. I once found them in fluids removed from two distinct cysts connected with the epididymis of a man about sixty years of age. 1 have detected them in the fluid from encysted hydroceles tapped for the first time, and also in the examination of small cysts connected with testicles removed after death. I removed from an old man aged 75, who had had encysted hydrocele for eight years, and which had never been tapped before, as much as thirty-two ounces of fluid, which contained an abundance of spermatozoa. They were also detected in fluid taken from a man aged 54, who stated that the tumour had existed for eight years, and had never been operated on.\nVarious opinions have been broached to account for the existence of spermatozoa in the encysted form of hydrocele of the testicle. The explanation which seems to me the most reasonable and probable, is that which I offered shortly after the occurrence of spermatozoa in encysted hydroceles was first discovered*, viz. that their presence is probably owing to the accidental rupture of a seminal canal, and the escape of its contents into the cyst of an existing hydrocele. The close proximity of the efferent tubes, the slight texture of the ducts and delicate walls of the cyst, and the liability of the part to contusion and injury, when a swelling even of moderate size exists, seemed to me to favour this view. The circumstance that spermatozoa are never found in very small cysts show that they are not originally formed there, but are a subsequent addition to their contents. Since my attention has been drawn to this subject I have investigated the history of the cases of encysted hydrocele containing spermatozoa, which came under my notice. In nearly all instances the patients assured me that the swelling had gradually formed after an injury to the testicle ; and in two cases it was clear that a small cystic swelling had long existed in a stationary state, but after a slight blow\n* Practical Treatise on Diseases of the Testis. Appendix, p. 541.\nhad begun to enlarge. I strongly suspect that, in these cases, a duct had been ruptured by the contusion, and that the irritation consequent on the injury, and perhaps on the addition of such lively bodies as spermatozoa to the fluid contents of the cyst, had led to its further development. I have, it is true, failed in establishing the fact of a communication between the duct and the cyst by anatomical examination. In two instances of large encysted hydrocele containing spermatozoa, which I had an opportunity of examining, I injected the vas deferens with coloured size, but the duct was so clogged with semen that the fluid could not be made to reach the head of the epididymis, to which the cyst was attached. In a preparation of large encysted bilocular hydrocele containing spermatozoa, shown me by Mr. Busk, the vas deferens had been injected with mercury, but none of the metal reached the upper part of the epididymis. The cyst evidently arose from the head of the epididymis, and was embedded a little in its substance. In these cases no opening communicating with a duct could be discovered on examination of the cysts, but this is not surprising, since the communication must be extremely minute, so as readily to escape detection, or it may even have been obliterated.\nSpermatozoa are stated to have been found in some two or three instances in fluid removed from the tunica vaginalis. It is not improbable that these cases may have been encysted hydrocles mistaken for simple. The diagnosis is sometimes very difficult, and in the case of the cyst examined by Mr. Paget,* this error was made before death by a hospital surgeon. I have, however, found spermatozoa in the sac of the tunica vaginalis, and the following case will account for their presence. A man aged fifty-four died in the London Hospital of disease of the kidneys, of one of the ureters, and of the bladder, which appeared to be consequent on a severe blow on the loins about six weeks before. The tunica vaginalis of one of the testicles contained two ounces and a half of slightly opaque fluid, in which a few spermatozoa were found. There were three small cysts containing fluid immediately connected with the epididymis, and also at one spot an irregular ragged membranous appearance, evidently caused by the rupture of a cyst. It is most probable that the spermatozoa had escaped from this cyst, which may indeed have been burst at the time of the injury. I have examined the fluid from the tunica vaginalis in a large number of instances without finding these bodies, and I believe their occurrence in the common form of hydrocele to be extremely rare.\nDiffused Hydrocele of the Spermatic Cord.\u2014 Mr. Pott has given an admirable account of this affection, under the denomination of hydrocele of the cells of the tunica communis, j- It has likewise been particularly described by\n* M\u00e9dico-chirurgical Trans., vol. 27. p. 398.\nf Vide his Treatise on Hydrocele.\n3 s 4","page":999},{"file":"p1000.txt","language":"en","ocr_en":"1000\tTESTICLE (ABNORMAL ANATOMY).\nScarpa.* The disease is of the nature of simple oedema, a watery fluid being diffused throughout the areolar tissue connecting the vessels of the spermatic cord, and enclosed in a sheath, which is invested by the musculo-aponeurotic structure of the cremaster muscle. \"When the complaint has lasted some time, the sheath is found more or less thickened. The areolar tissue within is infiltrated with a limpid albuminous serum of a white or yellowish colour, which flows out in the course of the dissection. The cells infiltrated with serum are converted into large vesicles, some of which are big enough to admit the tip of the finger. These cells are larger and more delicate towards the base of the swelling, where they sometimes disappear altogether ; so that there is only one considerable cavity at the lowest and more depending part. The base of the swelling corresponds to the point at which the spermatic vessels join the testicle, and at this part a dense septum cuts off all communication with the tunica vaginalis. In some instances the effusion extends along the cord into the abdomen, as in a remarkable case related by Mr. Pott. In the annexed figure of this affection, (fig. 643.), taken from Scarpa,\nthe envelope of the cremaster is laid open, exposing the pyramidal swelling enclosed in its sheath of condensed areolar tissue. The tes-\n\u2022 Memoria suif Idrocele de Cordone Spermatico. Bertrandi, an Italian surgeon, in a memoir published by the French Academy of Surgery, in 1778, has given an accurate description of this affection, which, however, he did not sufficiently distinguish from the encysted hydrocele of the cord. He dissected on the head body a diffused hydrocele, which contained twenty ounces of fluid.\ntide and tunica vaginalis are seen below it. In general anasarca the areolar tissue of the spermatic cord, as well as of the scrotum, is frequently distended with serum ; but oedema of the cord alone is a very rare affection. Sir A. Cooper makes no allusion to it, and Mr. Pott, to whom we are indebted for so good and accurate a description of this species of hydrocele, probably met with a greater number of cases of it than have occurred in the practice of any surgeon since his day.\nEncysted Hydrocele of the Spermatic Cord.\u2014 A cyst containing fluid may be developed in the loose areolar tissue of the spermatic cord. The cyst is formed of a thin transparent membrane, possessing the ordinary characters of a serous membrane, and contains generally a limpid aqueous liquid, having little or no albumen, but sometimes a straw-coloured serum similar to the fluid of simple hydrocele. It is of an oval form, and its size, though variable, seldom exceeds that of a hen\u2019s egg, and is usually smaller. It is loosely attached by areolar tissue to the vessels of the cord which are situated at its back part, but become separated and displaced by it. The cyst is invested by the common integuments, superficial fascia, musculo-aponeurotic sheath of the cremaster muscle, and fascia transversalis. It may occur either immediately above the testicle, in the middle of the cord, or just below the abdominal ring, and even within the inguinal canal. Usually there is a single cyst, but occasionally several are developed, and a chain of them has been formed along the cord. The cyst and its contents are liable to changes consequent upon inflammation. Encysted hydrocele of the cord appears to originate, in general, in a partial or imperfect obliteration of the prolongation of peritoneum drawn down at the period of the transition of the testicle. I have already described the different appearances presented by the remains of this prolongation, which, it has been remarked, sometimes consists of a single cyst, or of two or more sacculi, moistened by a serous fluid. When this fluid accumulates in any quantity, an encysted hydrocele is the result. Such is obviously the mode of origin of this affection when occurring in infants, and no doubt in adults it generally originates in the same way. M. J. Cloquet has remarked that the remains of the peritoneal process accompanying the testicles in their descent were met with in male subjects of all ages, and he mentions as a singular circumstance, that they were nearly as frequently found in the old as in the young subjects.* My own dissections agree with the observations of this accurate anatomist. In the museum at the London Hospital there is a preparation showing the tunica vaginalis continued for about two inches up the cord, and, immediately above it, an encysted hydrocele, which was taken from an adult subject. In dissecting the body of a man, aged eighteen, I found an encysted hydrocele of the cord\n* Description of the parts concerned in Inguinal and Femoral Hernia, tr. by McWhjnnie, p. 25.","page":1000},{"file":"p1001.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1001\nabove the testicle in close contact with the tunica vaginalis. Immediately above this cyst, but quite distinct from it, there was a narrow and empty serous sac three inches in length, with a contracted neck, and communicating with the abdomen. They are figured in the accompanying engraving, with the hernial sac\nFig. 644.\nlaid open, and part of the parietes of the encysted hydrocele cut away to expose their interiors. The position of the testicle is so changed that its anterior border is directed downwards. In the examination of the body of a man who died of disease of the heart, I found on the right side a thickened and empty serous pouch, extending for about an inch and a half below the external abdominal ring. Directly below it was an independent cyst, capable of containing a walnut, similar in structure to the hernial sac, but lined by a thin false membrane. The tunica vaginalis, which was healthy in structure, extended up the cord as far as the cyst, from which it was separated by a thick and firm partition. In opening the body of a sailor who died with ascites, I noticed at the internal ring a small, delicate, transparent, pedunculated cyst, not larger than a nut, projecting into the cavity of the abdomen. In the spermatic cord, there was a large serous cyst, which extended into the inguinal canal, and contained a small quantity of transparent fluid. A small orifice at its upper part opened into the pedunculated cyst, which proved to be a process from the cyst in the cord. In fig. 644., I have given a representation of an inguinal hernia, combined with an elongated encysted hydrocele of the cord ; and in fig. 647., a representation of an encysted h\u00e6matocele of the cord, in which the tunica vaginalis remained\nunobliterated as far up as the cyst, whilst a hernial sac is situated immediately above it. These dissections confirm the view taken by Sir A. Cooper, and now commonly adopted, of the mode of origin of encysted hydrocele of the spermatic cord in the adult.\nComplications of hydrocele.\u2014 The following are the principal : 1. Simple hydrocele, combined with encysted hydrocele of the testicle.\n2.\tSimple hydrocele, combined with encysted hydrocele of the spermatic cord. 3. Simple hydrocele, combined with diffused hydrocele of the spermatic cord. 4. Oscheo-hydrocele, including both simple hydrocele and encysted hydrocele, combined respectively with inguinal hernia.\n1.\tThe first is not an uncommon complication. In the dissection of these parts, I have often found the tunica vaginalis distended with three or four drachms, and even an ounce or two of serum, two or more small distinct cysts being at the same time connected with tlie upper part of the epididymis ; and I have twice met with this complication in both sides in the same individual. The small adventitious cysts appear to be the original disease, the irritation produced by them being in all probability the cause of the increased quantity of fluid in the tunica vaginalis.\n2.\tThe second complication is somewhat rare. In the pathological collection at the London Hospital, there are two specimens of a collection of fluid in the tunica vaginalis associated with an encysted hydrocele of the spermatic cord. In one of them the tunica vaginalis is unobliterated for about two inches along the spermatic cord, and the encysted hydrocele is immediately above it. In the other preparation it is apparent that both sacs have been the seat of inflammation, false membranes being contained within them. This complication sometimes occurs in infants.\n3.\tSimple hydrocele associated with diffused hydrocele of the cord is also rare. A good delineation of this complication is given in Scarpa\u2019s work.\n4.\tScrotal hernia may be combined with hydrocele. A voluminous hydrocele, if un-\nFig. 645.","page":1001},{"file":"p1002.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\n1002-\nsupported, appears to be highly favourable to the occurrence of hernia and the extension of the sac, by dragging down the peritoneum. Oscheo-hydrocele is not an uncommon complication. In most of the cases which I have met with, the hydrocele was placed below and free of the rupture, and in a few only in front of it. I have never found the hernial sac covering the fore part of a hydrocele. The ordinary relations of hydrocele and scrotal hernia may be seen in the accompanying woodcut. In figure 638., the sac of an inguinal hernia is represented at some little distance above a small hydrocele. Dupuytren states that, when a hydrocele is placed in front of a hernia, a part of the omentum or intestine sometimes descends into a cyst, which projects into the hydrocele, and is formed of the hernial sac and serous fold of the tunic of the testicle.* This complication is of the nature of the hernia infantilis, described by Mr. Key, and called by Sir A. Cooper encysted hernia of the tunica vaginalis.\nH\u00e6matocele.\u2014 This is a term applied to the swelling occasioned by effusion of blood in the sac of the tunica vaginalis, or in a cyst connected with the testicle ; it is also applied to tumours produced by extravasation, either in the substance of the spermatic cord, or in the sac of an encysted hydrocele of this part. Hcematocele of the testicle, in which blood is effused into the tunica vaginalis, is by far the most eommon form of this affection. The extravasation may take place in a healthy state of the parts, or it may succeed, or be combined with hydrocele, The first variety occurs from the accidental rupture of some blood-vessel, probably one of the vessels ramifying between the tunica albuginea and tunica vaginalis testis, owing either to a blow or a violent straining effort. The second variety, in which the extravasation takes place in combination with hydrocele, is of more frequent occurrence than the first. It may also be produced by a blow, or by the wound of some vessel, in the operation of tapping. A blow occasions a slight rupture of the tunica vaginalis, and of some of the enlarged vessels ramifying outside it, and the blood which escapes passes into the sac and mixes with the fluid of the hydrocele, producing a sudden increase in the size of the tumour. The liability to this accidental effusion of blood is increased by a diseased condition of the arteries, such as is commonly met with in old people. The quantity of blood effused under these circumstances varies considerably. It may be merely sufficient to impart a red tinge to the serum. In general, however, it is greater in amount, and coagula are formed, which remain undissolved in the fluid. A h\u00e6matocele may be produced in the operation of tapping a hydrocele, in two ways. It may be occasioned by the accidental wound of some vessel ramifying over the tunica vaginals, which, instead of bleeding externally, or into the areolar tissue of the scrotum, pours its blood into\n* Le\u00e7ons Orales. Brussels edit. t. iv. p. 233.\nthe sac of the hydrocele ; or it may be caused by the trocar or lancet penetrating too far, and wounding the testicle or spermatic artery.\nIn h\u00e6matoceles which have existed for a long period, the blood becomes changed into a substance resembling coflee grounds, of a brownish-red, or chocolate colour, and more or less fluid. The coagula sometimes present a cellular or honeycomb appearance, the cells being filled with a reddish serum. Occasionally the blood is found converted into a solid fibrinous substance, of a yellow or fawn colour, arranged in firm layers, similar to the coagula lining the sac of an aneurism. In many instances the effused blood is felt as a foreign body, and produces inflammation in the tunica vaginalis, which becomes coated with lymph, and this mixing with blood and serum modifies the appearance of the contents of the cyst, rendering it turbid and of a lighter colour. Sometimes the inflammation goes on to suppuration, in which case pus is also found in the sac. The inflammation usually extends from the tunica vaginalis to the areolar tissue and fascia external to the sac, which in recent cases are found infiltrated with serum and lymph, and in cases of old standing become greatly thickened, indurated, and compacted. In a case of h\u00e6matocele, occasioned by the wound of a vessel in tapping a hydrocele in which I was consulted, the inflammation which ensued caused, in the course of a fortnight, great thickening of the tissues external to the sac, and the formation of an abscess in the scrotum on one side of the h\u00e6matocele. I have found the tunica vaginalis and tissues investing it as much as half an inch in thickness, and very firm and dense.\nThese changes in the sac are produced by a more chronic form of inflammation of the fascia and areolar tissue investing the sac. In these old cases, the internal surface of the tunica vaginalis instead of presenting its natural smooth and polished surface, is rough, granular, and irregular, and feels as dense and tough as a piece of leather, having lost all the characters of a serous membrane. In h\u00e6matocele, the testicle preserves the same relation to the remainder of the tumour as in simple hydrocele, being situated at the posterior part, and rather below the centre. Its position, however, is liable to similar alterations as occur in hydrocele, and they are dependent upon the same causes. A young man had a hydrocele, which had succeeded to an attack of secondary orchitis, occasioning an adhesion of the gland to the front of the sac at its lower part. The case became converted into a h\u00e6matocele by the wound of a vessel in the operation of tapping. Inflammation ensued, and it became necessary to lay open the sac. The surgeon, in carrying the incision to the lower part of the tunica vaginalis, divided the vas deferens and severed the sound testicle nearly in two with his bistoury, the thickening around the sac having prevented him from detecting the gland in its unusual situation. In h\u00e6matocele, the","page":1002},{"file":"p1003.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1003\nglandular structure of the testicle sometimes disappears in the same manner as in old cases of hydrocele, atrophy being occasioned by the long continued pressure arising from the ex-travasated blood. Sir B. Brodie has recorded two cases of old h\u00e6matocele, in which the testicle was completely atrophied.* In the examination of a large h\u00e6matocele which had existed for many years, and was removed by operation, under the impression that it was a solid enlargement of the testicle, I found the tunica vaginalis nearly half an inch thick, and full of a soft friable substance of a chocolate colour ; the testicle, which was situated at the posterior part of the cavity, was somewhat flattened, and partly imbedded in the thickened cyst ; but the glandular structure was perfectly healthy, and the bulk of the organ scarcely less than natural. The h\u00e6matocele, with the sac and testicle laid open, is represented in the accompanying figure. The\nFig. 646.\nquite moveable, but attached to the epididymis. The cyst was opened with a lancet, and exit given to a quantity of dark coagula lodged in a thickened cyst, the interior of which was lined by a rough false membrane. No doubt the cyst existed before the injury, which caused effusion of blood and inflammation, and thickening of the cyst.\nH\u00e6matocele of the spermatic cord is an affection which was first noticed by Mr. Pott. It is generally produced by the accidental rupture of a spermatic vein, during violent and sudden exertion, as in straining to lift a heavy weight, when blood immediately escapes into, and infiltrates the loose areolar tissue along the cord, where it accumulates, its further diffusion being prevented by the fascious envelope of this part. Mr. Pott has related three cases, all of which happened in this way. I have met with this variety of h\u00e6matocele, coupled with extravasation in the scrotum, in two or three instances of contusion, of this part. In one case in which the effusion in the cord was on the left side the spermatic veins were varicose.\nEncysted h\u00e6matocele of the spermatic cord results from the effusion of blood into the cyst of a hydrocele of this part. But it is an affection only known to me from preparations. In the Museum of St. Bartholomew\u2019s Hospital there is a specimen of the kind. The cyst is empty : but it is described to have contained blood, and its walls are deeply stained with the colour of partially decomposed blood. Its lining membrane is wrinkled and coarsely granular, and the tissues around\nstructure of the testicle is usually indeed sound in h\u00e6matocele, but its nutrition becomes impaired when the disease is of very old standing.\nEncysted h\u00e6matocele of the testicle, or effusion of blood in a cyst connected with the testicle, is an extremely rare affection. The following is the only case of the kind that I have met with. I was requested by one of my colleagues at the London Hospital to examine a case of painful tumour connected with the left testicle. The patient, aged eighteen, had injured the part three months before. The scrotum was much swollen at the time of the accident, and the tumour formed afterwards. It was about the size of a chesnut,\n* Lond. Med. and Phys. Journal, vol. lviii. p. 299.\n1, testicle ; 2, hernial sac ; 3, encysted h\u00e6matocele.\nFig. 647.","page":1003},{"file":"p1004.txt","language":"en","ocr_en":"1004\tTESTICLE (ABNORMAL ANATOMY).\nit are thickened, brawny, and adherent together. In the Hunterian Museum there is a specimen (No. 2460.) of old encysted h\u00e6ma-tocele of the spermatic cord. A good-sized cyst, lined by a membrane, polished and a little wrinkled, is filled with a soft, tawny-looking granular matter, resembling the altered coagulum of blood observed in ordinary h\u00e6matocele after long maceration in spirit. The tissues around the cyst are thickened and indurated, just like those around an old h\u00e6matocele of the testicle. There is a hernial sac immediately above it, and a hydrocele below, with the sac open for some distance up the cord as far as the cyst of the h\u00e6matocele. The latter does not communicate either with the tunica vaginalis, or the hernial sac. In the Mus\u00e9e Dupuytren at Paris, I also saw a preparation of this affection, which occurred in the practice of the late M. Blandin.\nOrchitis. \u2014 Inflammation of the testicle occurs in two forms, acute and chronic ; and it may commence either in the body or secreting part of the organ, or in the epididymis. Inflammation beginning in the body of the testicle may be idiopathic, or may be excited by external violence : the disease is at first confined to the interior of the organ, the epididymis and tunica vaginalis being affected only secondarily, and sometimes entirely escaping. Orchitis is far more frequently a consecutive affection than a primary, the inflammation being transmitted from the urethra along the vas deferens. In this latter form of orchitis, which is familiarly known by the term hernia humoralis, the epididymis is first attacked, and the tunica vaginalis generally participates in the disease.\nAcute Orchitis. \u2014 Few pathologists have examined a testicle in a state of acute inflammation, and I am unacquainted with any authentic account of the alterations in structure from inflammation originating in the body of the gland. I have twice had the opportunity of examining a testicle affected with acute secondary orchitis ; and the following description of the pathological appearances is drawn up from these investigations, and from the account of the dissection of two testicles affected with gonorrhoeal inflammation recorded by M. Gaussail.* The tunica vaginalis is more or less distended with lymph or albuminous matter, infiltrated with reddish serum, which form loose adhesions between the opposed surfaces of the membrane ; these adhesions are so slight as easily to admit of being broken down with the finger. The membrane is injected with a multitude of minute red vessels which ramify in various directions and form a compact network. At a later period red ves-vels may be traced proceeding from the free surface of the tunica vaginalis to the false membranes forming the adhesions. The volume of the testicle appears very little if at all increased, the great bulk of the tumour\n* M\u00e9moire sur l\u2019Orchite Blennorrhagique, Archives Generales de M\u00e9decine, tom. xxvii. p. 210.\nbeing occasioned by the swollen epididymis and effusion into the serous sac. When cut into, the gland appears somewhat darker than natural, from a congested state of its vessels. The epididymis, particularly the lower part, is enlarged to twice and sometimes thrice its natural size, and feels thick, firm, and indurated. This enlargement is produced by the effusion of a brownish deposit in the areolar tissue between the convolutions of the duct. The coats of the vas deferens are thickened, and the vessels ramifying near them injected, sometimes along the whole extent of the duct. Albuminous deposit is found in the areolar tissue around the tortuous part of the vas deferens and tail of the epididymis, which frequently forms the bulk of the swelling observed in these cases. Owing to the epididymis being the part chiefly and most constantly affected in consecutive orchitis, some of the modern French writers have denominated the disease epididymitis.\nIn treating of the acute inflammatory changes in the tunica vaginalis, 1 particularly remarked that the inflammatory action was very liable to extend to the substance of the epididymis, but not to the body of the testicle, and I noticed the pathological law enunciated by Gendrin, by which the circumstance was accounted for. We find, too, that inflammation of the epididymis is much more readily propagated to the tunica vaginalis than inflammation originating in the glandular structure of the testicle. When inflammation commences in the body of the gland, the enlargement takes place slowly, and is seldom considerable until the disease has existed for some length of time, which is easily explained by the unyielding texture of the tunica albuginea, and the circumstance of the tunica vaginalis remaining unaffected. Suppuration occasionally takes place in this form of orchitis, whereas in consecutive inflammation the formation of pus in the substance of the gland is of rather rare occurrence. I do not mean, however, to assert, that the glandular structure of the testicle never suffers in consecutive orchitis, for I believe that it does so in some instances ; but, according to my observations, and I have paid some attention to the subject, it very commonly escapes, the inflammation not extending further than to the epididymis. When inflammation terminates in suppuration, the matter is so slow in making its way externally, owing to the density, thickness, and low organisation of the tunica albuginea, that it generally burrows in various directions, producing numerous sinuses throughout the gland, and disorganising its delicate structure. The matter sometimes becomes encysted, forming a separate abscess.\nIn these cases, when the matter effused is small in quantity, after all inflammation has subsided, the more fluid particles are absorbed, and the pus remains for a considerable time in the form of an indolent concrete mass, which has been mistaken, after death, for tubercular deposit. The pus when found in this concrete state appears at first sight very","page":1004},{"file":"p1005.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1005\nlike crude tubercular deposit ; but on further examination it will be found to be contained in a distinct cyst, from which it may easily be separated, and the structure of the testicle will be perceived to be more or less altered from its healthy state; whereas in tubercular disease, the morbid deposit is in immediate contact with the tubular structure, which, though atrophied by pressure, is usually in other respects sound. Concrete pus may likewise be mistaken for the firm yellow matter effused in chronic inflammation. It differs from it, however, in being friable and easily broken up, and also in being enclosed in a cyst, whereas the yellow fibrinous substance is homogeneous and consistent, and almost inseparably diffused amongst and connected with the convoluted tubuli around it. The distinctive characters just described will be easily recognised on comparing the accompanying representation of concrete pus encysted in the testicle with fig. 651.\nFig. 648.\nI examined two enlarged testicles taken from a man who died suddenly. Both glands had formerly been attacked with acute inflammation, and for some months before death they had been the seat of chronic pain. In the left testicle, which was the larger of the two, from two to three drachms of thick yellow inspissated pus were contained in a distinct cyst, which occupied the centre of the gland. There was no trace of tubuli, but the remainder of the organ was composed of a fibrous tissue : the sac of the tunica vaginalis was obliterated by close adhesions. The tunica vaginalis of the right testicle contained about half an ounce of yellowish serum and in the centre of the gland there was a small concrete abscess, but the tubular structure was apparent and very little diseased. Pus existing in this concrete or inspissated state often keeps up pain and irritation for a long period, and renders the testicle liable to repeated relapses of inflammation.\nSuppuration occasionally takes place in the\nepididymis. In several cases of consecutive orchitis which have come under my care, at a late period of the disease an abscess formed in the areolar tissue around the termination of the epididymis and inflected portion of the vas deferens, and burst at the most depending part of the scrotum. In many instances, after acute orchitis has subsided, the testicle is restored to its natural condition ; in other cases, permanent changes of a serious nature are the consequence. I have observed in testicles that have been affected with inflammation some time before, that the septa appear to be more distinct, and to enter more largely into the composition of the gland than is natural ; that the small seminal tubes are less numerous and apparent ; and that a great part of the organ is converted into a dense white fibrous tissue, without the presence of tubuli. In these cases the fibrinous matter effused in the areolar tissue connecting the tubuli, not having been absorbed after the cessation of inflammatory action, had occasioned partial atrophy of the proper structure of the organ, and been converted into the dense tissue just described. Complete atrophy is one of the most serious results of acute inflammation of the testicle. I have already remarked that the disturbance in the organisation of the testicle consequent upon inflammation is the most common cause of wasting. Consecutive orchitis, if not checked in the early stage, seldom subsides without leaving behind distinct traces of its existence, which never disappear entirely during the remainder of the patient\u2019s life. The epididymis frequently remains enlarged, presenting an indurated irregular knotty swelling, seated usually at its lower part, which is occasioned by the presence of a dense hard deposit between the convolutions of the duct and around the inflected portion of the vas deferens. On making a section of the epididymis in this state, I have often observed not only a highly thickened condition of its duct, but also, in some instances, very considerable dilatation ; so that the point of a fine probe might be introduced into the canal without difficulty, its area being increased four or five times. These effusions about the duct rarely if ever produce its obliteration, the yielding nature of the tissues preventing this injurious result. In old cases the epididymis acquires the density and consistence of cartilage, and sometimes even of bone. These changes are rarely found without the presence of old adhesions, obliterating partially or completely the sac of the tunica vaginalis. The coats of the vas deferens are also found for some extent thickened and indurated. The alterations noticed in the body of the testicle have been observed, in some instances, coexisting with those in the epididymis ; but in by far the majority of cases, the glandular structure is unimpaired. In only two cases in which the epididymis was thus diseased, have I remarked a decidedly atrophied condition of the organ. The absence of pressure, owing to the unresisting nature of the membrane investing the","page":1005},{"file":"p1006.txt","language":"en","ocr_en":"1006\tTESTICLE (ABNORMAL ANATOMY).\nepididymis, appears to prevent the obliteration of the duct of which it is composed, and thus accounts for atrophy occurring much more rarely after consecutive orchitis than after inflammation originating in the body of the gland, where the delicate seminal tubes are enclosed in the firm unyielding tunica albuginea.\nChronic orchitis. \u2014 The testicle is liable to a form of inflammatory swelling of a distinct and chronic character, which occasionally succeeds acute orchitis but far more commonly arises spontaneously. The disease is of importance ; for, if unchecked, it tends to disorganise and destroy the gland. The chief anatomical character of this form of inflammation is the deposit of a peculiar yellow, homogeneous, inorganic matter in the structure of the testicle. This substance when first formed is of soft consistence, but afterwards becomes firm and solid, and so closely adherent and intimately blended with the proper structure of the organ as not to admit of separation without much difficulty. In some instances there is a single deposit of this substance in the centre of the glandular structure, as in the preparation from which the annexed woodcut was taken. In others\nFig. 649.\nseveral are interspersed throughout the testicle, portions of sound gland intervening. In a case of chronic enlargement of both testicles taken from a patient who died of ramollissement of the medulla spinalis, I found six or seven separate deposits of this yellow matter in the substance of the right testicle, and a single one only in the body of the left. The small masses as they enlarge coalesce, or the single one increases, until the whole testicle presents an uniform yellowish-white appearance. The epididymis is frequently invaded at the same time by a similar kind of morbid deposit, which also tends to obliterate its tubular structure. This, however, is not, as some pathologists suppose, a constant occurrence ; for in the majority of testicles thus diseased that 1 have examined, the epididymis had entirely escaped. I have\nnever succeeded in injecting this deposit, or in tracing vessels into it. But the vessels of the testicle generally are enlarged. Pathologists have differed as to the particular tissue in which this yellow matter is deposited. Sir A. Cooper and Cruveilhier describes it to be seated in the areolar tissue between the tubuli; whilst Sir B. Brodie is of opinion, that it is secreted from their inner surface, as he discovered the yellow substance in the canal of the epididymis and also in the vas deferens which are continuous with the tubuli. I have had the opportunity of inspecting a testicle affected with this disease, in what seems to me to be its early stage from which examination I think I have been able satisfactorily to confirm this opinion. The testicle was injected with red size, and a section then made of it. The surfaces of the tunica vaginalis were partly adherent, and about three drachms of serum were collected in one part of the sac. The body of the testicle was not much enlarged : it contained, however, an abundant deposit of a firm opaque matter. Near the anterior edge of the testicle this deposit appeared in the section like round isolated yellowish-grey bodies, separated from each other by portions of the sound structure of the gland : about the centre of the organ it assumed a beaded arrangement, and towards the mediastinum formed a number of closely-set yellow lines or processes, radiating towards the posterior part of the testicle, where they were amalgamated into one uniform mass. Further examination perfectly satisfied me that this matter was lymph deposited in the tubuli seminiferi. The isolated and beaded appearances in the section resulted from breaks in the lymph thus deposited. The real seat of the effusion was very evident, from the arrangement described near the mediastinum. With a good lens some of the convoluted tubuli could be distinctly seen, filled with and dilated by the morbid deposit. A portion was carefully examined in the microscope with a similar result. The epididymis was\nFig. 650.\n1, fistulous sinus leading to the suppurating cavity in the head of the epididymis ; 2, concrete abscess in the tail of the epididymis.","page":1006},{"file":"p1007.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1007\nmuch enlarged ; its head was filled with soft concrete matter, surrounding an irregular cavity with which a fistulous sinus communicated ; its tail contained a similar substance without any external opening. The various appearances described are depicted in the adjoining figure, which was taken from the recent specimen. Similar appearances to those noticed in this case have been described and figured by Cruveilhier, in his \u201c Anatomie Pathologique.\u201d* He considers that the disease proceeds from the head of the epididymis towards the tail, and that the body of the testicle is affected only consecutively. I believe, myself, that the yellow deposit is the ordinary result of chronic inflammation of the testicle in whatever way produced ; but that the peculiar appearances noticed in the case just related and likewise described by Cruveilhier, \u2014 I mean the small isolated masses in the substance of the gland, and radiating towards the mediastinum,\u2014are only observed in those cases in which the disease originates in the epididymis, and thence spreads to the body of the testicle, and in which the part is examined before the organ has become extensively diseased. These appearances are not often seen, because it is not often that it becomes necessary to remove a testicle in such a condition, which is indeed a curable one unless complicated with suppuration. Cruveilhier supposes that this matter is effused in the areolar tissue of the testicle, and radiates along the fibrous prolongations from the corpus Highmori. I feel satisfied, however, from my own observations, that he is mistaken, and that the interior of the tubuli is the original seat of the deposit. This yellow substance has been called the yellow tubercle of the testis ; but, as it differs from tubercular deposit, the term is objectionable and liable to lead to error. It is evidently coagulable lymph, which becomes more solid in the testicle than in most other parts, owing, perhaps, to the condensation consequent on the firm resistance offered to any enlargement of the gland by the unyielding tunica albuginea. This disease is often accompanied with effusion of serum into the tunica vaginalis, seldom amounting, however, to more than three or four ounces. Lymph also is sometimes deposited, and the sac may become partially, or totally obliterated by adhesions.\nThe peculiar matter effused in this disease under appropriate treatment undergoes complete absorption, the testicle being left in a condition to perform its natural functions. It sometimes happens, however, that ulceration ensues in its tunics and integuments, and that a fungous-looking growth gradually protrudes through the opening which is thus formed. This fungous growth is sometimes termed granular swelling ; it has also received the name of hernia testis, being formed in a manner very analogous to that of a hernia cerebri, in which the substance of the brain js protruded through an ulcerated opening in\n* Liv. v. pi. b., and liv. ix. pi. i.\nthe dura mater. It appears that the yellow deposit after some time excites ulceration in some part of the tunica albuginea. The tunica vaginalis, and afterwards the skin, become adherent at this spot, and likewise inflame and ulcerate. The resistance afforded by the dense unyielding tunica albuginea being thus removed, the adventitious deposit gradually presses out the tubular structure, which forms a projecting tumour consistingTof the tubuli mixed up with this yellow substance, and also of ordinary granulations which spring up from the seminiferous structure. This projecting growth presents an ash or yellowish-white appearance, varied by irregular patches of a pale red hue, and sometimes of black. It is closely girt by the scrotum, the ulcerated edges of which are often thickened and everted, (fig. 651.)\nFig. 651.\nThe mass often projects so much that scarcely any part of the organ is contained within the scrotum. Though this hernial growth occurs most frequently in an advanced stage of the chronic form of inflammation, it is developed in other diseases of the organ which occasion ulceration of the tunica albuginea, and thus afford an opening for the escape of its contents. It is occasionally the result of an attack of acute inflammation supervening upon the chronic disease, and terminating in suppuration in the substance of the gland. In a case of this kind, in addition to the glandular swelling, there are sinuses more or less numerous, which burrow in the interior of the organ, and discharge pus mingled with the yellow matter. An attack of orchitis, originally acute, going on to suppuration, is also liable to be followed by a fungous protrusion of the secreting structure of the gland. In the latter case, the growth is not so exuberant, and the seminiferous structure is more distinctly apparent, owing to the absence of the yellow matter ; but there are generally sinuses which furnish a purulent discharge, sometimes mixed with semen. Tubercular matter deposited in the testicle may also lead to suppuration, and the formation of a granular swelling.\nA testicle after becoming somewhat enlarged from chronic inflammation, often continues indolent and stationary for years, giving rise to very little inconvenience. On examining the organ in this state, the yellow adventitious deposit is found to possess con-","page":1007},{"file":"p1008.txt","language":"en","ocr_en":"1008\tTESTICLE (ABNORMAL ANATOMY).\nsiderable firmness and consistency ; the tunica albuginea is thickened, and in some places as dense and indurated as cartilage ; and the surfaces of the tunica vaginalis are closely connected by old adhesions. The glandular structure is partly displaced and atrophied by the pressure of the yellow matter ; and it often happens after some time, that both undergo a slow process of wasting, so that an enlarged and indurated gland is progressively reduced, until scarcely any thing remains beyond a mere nodule of the size of a nut at which the spermatic cord terminates. I found, on examination of the body of a man who some few years previously had suffered from chronic inflammation of the testicles, both glands much indurated, but about the natural size. In both, the tubular structure was very deficient, its place being supplied by a dense fibrous tissue. At the upper part of the right testicle there was a yellowish deposit almost as dense as cartilage, and exhibiting very little trace of vascularity. In these indurated testicles the epididymis often escapes the morbid alteration affecting the body of the gland ; in other cases, however, the epididymis is also found nodose, irregular, and hard. It will be perceived, from the preceding observations, that the tendency of this chronic disease is gradually to destroy the integrity of the testicle. If the inflammation be checked in an early stage, the gland is left unimpaired ; if its course be not arrested until a later period, the secreting structure is partly disorganised and reduced in size ; but if the disease be allowed to continue unchecked by treatment, the organ is totally destroyed, either by ulceration of its tunics and the escape of the glandular structure in the shape of a fungous growth, or by the slower process of wasting and absorption.\nSyphilitic orchitis is essentially of the same nature as the chronic orchitis just described. It commonly commences in the body of the gland and rarely terminates in suppuration, or in the production of a hernial fungus. Sir A. Cooper states that in the majority of cases the disease attacks both testicles. The eight examples recorded in his work do not, however, bear out this remark; for in only two of them does it appear that both organs were attacked. According to my observation, the disease is more commonly confined to a single gland, though it occasionally affects both : this appears to be the opinion also of Ricord.* The appearances on dissection correspond with those observed in chronic inflammation.\nTubercular Disease. \u2014 In the testicle,\"'this deposit is met with in the crude state, forming a yellow caseous substance similar to the tubercular matter occurring in the lymphatic glands. It is sometimes developed in a single mass ; at other times several distinct depositions are formed in different parts of the organ : in both cases at the expense of its glandular structure, which becomes atrophied\n* Trait\u00e9 Pratique des Maladies 'V\u00e9n\u00e9riennes, p. 640.\nas the disease advances. The epididymis is more frequently affected than the body of the gland. In a specimen taken from a man who died of phthisis, I found the whole of the epididymis occupied by tubercular matter, with scarcely any trace of tubuli; whilst the body of the gland, though small, was perfectly sound and unaffected, (fig. 652.) In some Fig. 652.\ncases I have seen two, three, or more distinct tubercular deposits, separated by portions of healthy gland. This was the case in both testicles removed from a middle-aged man who died of phthisis. In some instances these isolated masses appeared to be contained in cysts formed by the processes from the tunica albuginea which separate and support the lobules. Sometimes the separate deposits seemed to be coalescing and joining together, so as to form one continuous mass ; and I have found a single mass of tubercular matter surrounded by glandular structure expanded into a thin layer. In other specimens the whole testicle was occupied by a homogeneous cheesy mass, without any trace remaining of the original structure of the gland. In some instances in which the disease was thus advanced, there was very little increase in the size of the testicle ; it only felt heavier and harder than in the natural state. In others, again, there was either a general uniform enlargement, or an irregular swelling at some part, commonly at the head of the epididymis. Some of these testicles, in which the disease was not much advanced, when injected made beautiful preparations, the yellow inorganic tubercular matter contrasting in a marked degree with the vermilion hue of the intervening sound portions of the organ. On several occasions I found a small quantity of serum in the tunica vaginalis, with partial adhesions and depositions of lymph. In a further stage of the disease, the characteristic deposit becomes softened down, and converted into a yellow pultaceous substance, evidently tubercular matter mixed with pus. The abscess extends to the scrotum ; and after it has burst and the matter has escaped externall}', cavities and sinuses are left which may be said to resemble the tubercular cavities in the lungs. The course of the disease, however,","page":1008},{"file":"p1009.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\nin the testicle, more nearly resembles the changes which ensue in tubercle of the absorbent glands.\nIt has been a question whether the tubercular matter is originally formed in the areolar tissue connecting the tubuli, or in the tubuli themselves. I have certainly seen this deposit in the vas deferens near the testicle, and within the ducts of the epididymis. Dr. Carswell has given a representation of a testicle containing , a multitude of pale yellow-colon red granular bodies of various sizes, which, he says, were obviously formed by the accumulation of tuberculous matter in the tubuli seminiferi. The epididymis was as thick as the little finger, and its convoluted ducts were obviously filled with a similar deposit. I believe that tubercle may be deposited in both situations, within as well as between the tubuli. Earthy matter is sometimes found in the testicle, generally in the epididymis, the part most frequently the seat of tubercle. This substance is exactly similar to the putty-looking chalky matter often observed in the lungs and bronchial glands. It is highly probable that, in these cases, the gland had at some former period been the seat of tubercular deposit, but I have not yet been able to establish this point satisfactorily.\nCarcinoma. \u2014 This disease occurs in the testicle under the four forms of Scirrhus, En-cephaloid, Colloid, and Melanosis.\nCarcinoma seldom occurs in the testicle in the dense form which it commonly assumes in the breast. Sir A. Cooper describes a scirrhous disease of the testicle, in which the gland is invaded by a large white mass in lobes or tubercles. The spermatic cord is affected with a similar disease, and the glands of the abdomen become converted into a white solid texture, very unlike that of the fungoid disease. I have a man, 52 years of age, under my care at the present time, with this disease of the testicle. It forms a tumour about three times the natural size, and is almost of stony hardness, especially at the back part. There is also a large indurated tumour in the spermatic cord. This affection of the testicle is very rare, and is characterised by its slow progress as well as by its great induration.\nEncephaloid cancer is by far the most frequent form of malignant disease to which the testicle is liable. When first observed, it is found in one or two masses amongst the tubuli, which gradually become destroyed as the morbid deposit accumulates. The matter is very rarely infiltrated. The testicle at this early period is extremely firm and hard, owing, not to the solid nature of the substance effused, but to the excessive distention of the unyielding tunica albuginea by the morbid growth within. The glandular structure soon entirely disappears, the whole organ being occupied by the new growth, intermixed with and sustained by the septa and fibrous processes from the mediastinum and tunica albuginea. In some instances a thin\nVOL. IV.\nlayer of the tubular structure is found expanded around a mass of encephaloid matter. At this stage the tunica vaginalis is often distended with serum ; not, however, in any considerable quantity. The tunica albuginea next gives way, and a portion of the morbid growth protrudes, forming a mass projecting from the body of the gland ; this sometimes occurs in more places than one. The epididymis remains for some time unaffected; but, as the disease increases, this part likewise becomes implicated and destroyed. In one instance I found the tubes in the head of the epididymis (the only part of the gland not destroyed) filled with white matter which, on microscopic examination, proved to be carcinomatous. The scrotum in a short time becomes fully distended by the diseased mass, which presents the well-known appearance of encephaloid cancer ; viz. a homogeneous substance of the consistence of brain, and easily broken down with the fingers, of an opaque white colour, and variegated with patches of a pinkish hue. It is sometimes mixed with small cysts containing serum ; at other times with yellow deposits of lymph, resembling that effused in chronic orchitis. These small depositions of yellow fibrine occasionally interspersed amongst the carcinomatous matter, are almost peculiar to this disease in the testicle. I have only once observed them in cancer of other parts, and that was in the kidney. As the enlargement goes on, the scrotum becomes adherent to the tumour in one or more places, then ulcerates, and allows the protrusion of the morbid mass, which projects as an open fungus. The scrotum admits however of great distention before ulceration ensues. The mass then becomes less firm, and its consistence varies very much in different parts, the morbid matter being in some a mere pulp, or resembling a creamy fluid. It is interspersed with round or irregular patches of dark looking coagula, and, when incised, often presents in different places dark minute spots of various sizes, produced by coagulation of blood in the vascular network usually mixed up with the morbid deposit. On macerating these tumours, or on pouring a stream of water on them for some time, a granular substance, the cancerous matter, is washed away, leaving behind a filamentous shreddy tissue or meshes of a delicate areolar texture, which may often be found connected to a denser fibrous substance, the remains of the tunica albuginea. The spermatic cord is often invaded by a similar substance; and in an advanced stage of the complaint, large bodies of the same kind, originating in disease of the lumbar glands, are found on the sides of the vertebrae, reaching as high up as the diaphragm.\nMasses of a similar kind are sometimes also found in the lungs. The carcinomatous matter is often deposited in such abundance as to form a tumour of very considerable size ; indeed, there is no other disease of the testicle which occasions solid en\u00bb\n3 T","page":1009},{"file":"p1010.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\nlargements of so great a magnitude as ence-phaloid cancer. M. P. Boyer removed a testicle converted into an encephaloid tumour which weighed more than nine pounds.* The vessels of the cord undergo great enlargement in this disease. In one case which I examined, the spermatic artery was found as large as the radial artery at the wrist. Cancerous germs have also been found in the blood contained in the spermatic veins. Encephaloid cancer of the testicle occurs at all periods of life : no age, indeed, can be said to be exempt from it. There are examples on record of operations for the removal of testicles thus affected, within a twelvemonth after birth. On the other hand I have met with the disease as late in life as the age of sixty-four. It more commonly occurs, however, in the middle period of life, or between the ages of twenty and thirty.\nCarcinoma has, in some few instances, been found to originate from the tunica vaginalis, the glandular part of the testicle remaining for some time unaffected. Cases of the kind have been recorded by Sir E. Home f and Sir A. Cooper. The other two forms of cancer, colloid and melanosis, have rarely been observed in the testicle. A preparation of the former disease is contained in the Museum of Guy\u2019s Hospital. The organ is enlarged to four or five times its natural size, but preserves its oval form : there is scarcely any trace of the natural structure remaining, its place being supplied by colloid matter. Cru-veilhier has related the case of a man who died of melanosis affecting the hand, lungs, heart, stomach, and other parts. There was a deposit of the same character in each testicle.\nCystic Disease. \u2014 The cysts developed in the substance of the testicle and constituting this disease vary very much both in number and size, and in the appearance of their contents. They may be only two or three in number, or they may exist in a countless multitude and occasion considerable enlargement of the organ. They vary in size from that of a millet seed to the dimensions of a pigeon\u2019s egg. At an early period they generally consist of smooth and slightly vascular cysts, closely adherent, and containing a transparent light-coloured fluid. In other cases the fluid is thick, viscid, and highly albuminous, and sometimes tinged with blood. I have never succeeded in detecting spermatozoa in the fluid. Sometimes a small tabulated growth arises from the walls of the cyst, and increases until it is partly or wholly filled and obliterated. The cysts usually increase at the expense of the secreting structure of the testicle, which disappears or becomes much displaced. In some instances the tubular structure forms an expanded layer over the morbid mass. When inflammation takes place, fibrine is effused between as well as within the cysts, and be-\n* Ttevue M\u00e9dicale. Nov. 1839.\n! Observations on Cancer, p. 125. Anatomie Pathologique, liv. xix. pi. 3, 4.\ncomes organised ; so that the tumour is partly solid and partly composed of cysts containing fluid. After some time, the surfaces of the tunica vaginalis become more or less adherent, and in old cases the tumour is intersected with fibrous bands. In several specimens of the disease I have noticed small masses of enchondroma interspersed amongst the cysts. In sections the little pearly-looking masses appear as if contained within the cysts. They are however developed between them, and are closely connected with their walls. The occurrence of enchondroma in these cystic tumours has scarcely been noticed by pathologists. There are several specimens in the \"Museum of the College of Surgeons.\nFig. 653.\nPortion of the section of a testicle in the Museum of the College of Surgeons, with numerous masses of enchondroma between the cysts, of the exact size, a. a. enchondroma.\nOne of the specimens of cystic disease in this collection measures five inches in its largest diameter, and three inches in its smallest. Sometimes small tabulated growths arise from a part of the walls of the cyst, and increase until the cavity is partly or wholly filled and obliterated by them, in the same manner as in cystic disease of the mamma.\nThe mode of origin of these cysts has not been satisfactorily made out. It has been supposed that they are formed of dilated and obstructed seminiferous tubes ; but as in certain cases the tubular structure exists in the form of a layer spread over the morbid mass, it is clear that the disease could not have originated in this way. This morbid change is evidently quite distinct from the little cysts so commonly developed in the head of the epididymis : indeed this part is rarely affected in cystic affections of the testicle. The disease is considered by some pathologists to be of a malignant character. After removal of a testicle thus diseased, tumours of a carcinomatous character have afterwards appeared in the lumbar glands and other parts. Mr. Caesar Hawkins showed me several preparations of cystic sarcoma of the testicle which had been removed by operation where this happened, and it occurred also in a case which came under my own observation. The unexpected result in this instance led me to pay attention to the matter, and I am now quite satisfied that the cystic disease may be","page":1010},{"file":"p1011.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1011\ndeveloped under two forms. In one, it occurs in combination with carcinomatous deposit :\nFig. 654?.\nSection of a cystic tumour of the testicle, showing a multitude of cysts of various shapes and sizes, with solid matter interposed betwen them. The natural glandular structure is wholly destroyed.\nin the other and more common form, the tumour is of an innocent character, and free from the risk of disease attacking other parts after removal of the organ. In the former the cysts are larger and less numerous than in the latter. By careful examination and with the aid of the microscope the coexistence of the two diseases may generally be made out.\nOssifie deposits in the testicle. \u2014 Earthy matter occurs in the testicle under two forms : 1. Laminated, and often mixed up with cartilage ; and 2., as an inorganic deposit. In the first form it is usually deposited between the tunica vaginalis and tunica albuginea, in little bony or cartilaginous patches, in which a fibrous arrangement may be recognised. I have frequently found one or two irregularly-shaped projecting ossifie bodies scarcely larger than a pin\u2019s head attached to the upper part of the testicle. Ossifie matter occurs also on the adherent surface of the tunica vaginalis in old cases of hydrocele, where it has been found so abundant as to form a complete ossifie capsule. It has been said that the epididymis alone may be encased in bone, the testicle being free ; this I have never seen. Bony matter occurs, however, in the substance of the epididymis as the result of ossification of the product of inflammation. Earthy matter in this form is not often ob-\nserved in the substance of the testicle. The gland, however, when atrophied and reduced to a mere fibrous tissue, occasionally undergoes both the cartilaginous and osseous transformation. The cysts developed in the testicle, as I have already shown, are liable to similar changes.\nIn the second form the earthy matter is deposited in an irregular mass, containing very little animal matter ; in appearance resembling mortar, and very similar to the earthy substance found in the lungs and bronchial glands. It is generally met with in the head of the epididymis, and sometimes in the lower part, and but very seldom in the body of the testicle. As I have already stated, it is most probable that this earthy matter results from the transformation of tubercular matter deposited in the testicle in early life.\nLoose bodies in the tunica vaginalis. \u2014 Loose bodies are occasionally found in the cavity of the tunica vaginalis. They are small in size, and of an oval flattened shape, and their surface is smooth and polished. Their texture is in most instances elastic and homogeneous, resembling the unattached cartilages found in joints, and points of ossification are often contained in their interior. In some specimens I have observed the cartilaginous matter to be arranged in concentric laminae. The loose body is sometimes entirely composed of bony matter. On examining a thin lamina of one in the microscope, I could distinctly see small oval corpuscules with a number of lines proceeding from them very similar to those of bone. They seldom exceed three in number, and they occur generally in combination with hydrocele, the loose bodies being the original disease.\nF\u0153tal remains in the testicle. \u2014 The remains of a foetus have been found in some rare instances, in the scrotum, in connection with the testicle. Several examples of the kind have been collected by Ollivier (D\u2019Angers).* In all these cases it was evident that the scrotal inclusion had succeeded to an inclusion originally abdominal; that is to say, that the organic debris were first situated in the abdomen in connection with the testicle, and had accompaniad the gland in its passage out of that cavity. In the cases in which the particular testicle was indicated, the right was the one affected.\nVaricocele is a term applied to a morbid dilatation of the spermatic veins. On dissection they are found dilated, elongated, and more tortuous than natural, and apparently more numerous, owing to the enlargement of the smaller vessels. In an advanced stage of the disease, their coats are thickened ; so that when divided the vessels remain patent, and thus present the appearance of arteries. The enlarged veins hang down below the testicle, and reach upwards into the inguinal canal ; and when very volu-\n* Memoire sur la Monstruosit\u00e9 par Inclusion; Archives G\u00e9n\u00e9rale de Medicine, t. xv. p.-540.\n3 T 2","page":1011},{"file":"p1012.txt","language":"en","ocr_en":"1012\tTESTICLE (ABNORMAL ANATOMY).\nminous conceal the gland, encroach on the septum, and extend to the other side of the scrotum. In a specimen which I carefully examined, the vessels were arranged in three clusters (fig. 655). One formed of the larger vessels proceeded from the inferior extremity of the testicle ; the second, in which the vessels were less in size, but more numerous and tortuous, arose from the upper ex-\nFig. 655.\ntremity of the testicle ; whilst the third and smallest cluster surrounded and accompanied the vas deferens (1). The dilatation is not confined to the veins exterior to the gland : even those in the organ itself are varicose, and enlarged veins may often be distinctly seen ramifying between the tunica vaginalis and tunica albuginea. The veins occasionally contain phlebolites which are lodged in dilatations of the vessels. The veins of the left testicle are more subject to varicocele than those of the right. In upwards of 120 operations performed by Breschet, in only one instance was the varicocele on the right side.* Pott met with this disease on both sides of the body in only one instance. The disease, however, is far from being so rare on the right side as is generally supposed, and often exists on both at the same time, although the varicose state of the right spermatic veins is always much less than that of the left. Of the causes of varicocele, some operate on both sides, others only on one. The most influential of the former is the hydrostatic pressure consequent *\nLandouzy, Du Varicocele, p. 24.\nupon the depending position of these veins, which have to support the weight of a column of blood extending from the testicle to the second dorsal vertebra. The absence of valves is mentioned as a circumstance conducing to this disease ; but this is an error, for the larger spermatic veins are always furnished with valves, though the dilatation which takes place in varicocele prevents them performing their office. There are several anatomical circumstances, which, taken together, are sufficient to explain the frequency of varicocele on the left side. On the right side the spermatic vein joins the vena cava nearly parallel to the axis of that vessel, so that the blood enters in the course of the circulation ; but on the left side the spermatic vein terminates in the emulgent vein at a right angle, and in a direction perpendicular to'the venous current from the kidney, which is less favourable to the return of blood from the testicle, since the two currents pursue a different direction. The left testicle hangs lower than the right, consequently the veins must be longer, and the pressure produced by the column of blood greater on the left side than on the other. The accumulation of the f\u00e6ces in the sigmoid flexure of the colon previous to an evacuation tends to produce pressure on the spermatic vein, and impede the return of blood from the left testicle, especially in persons whose bowels are habitually constipated. Some persons subject to varicocele suffer from it only when the bowels are in this condition. But even the natural daily accumulation may be sufficient to produce obstruction. To this cause, we must chiefly attribute the circumstance that a varicose dilatation of the veins of the ovary in the female is nearly always confined to the left side.\nIn the slight degree and chronic state in which we most frequently meet with this affection, no injurious effect is produced on the testicle ; but when highly or rapidly developed, the dilatation of the veins interferes so much with the nutrition of the gland as to occasion wasting. A partial atrophy of the gland, coexisting with varicocele has come under my notice in more than twenty instances ; indeed, in nearly all cases in which there was a decided dilatation of the spermatic veins on one side only, the testicle of that side w as the smaller of the two. In a man, aged fifty-six, with a varicocele on the left side, the testicle was so reduced that it scarcely exceeded the usual size of the organ in an infant. Some years ago, a tall sailor was under my care on account of a varicose ulcer on the left leg, who had a large varicocele on the left side, and a testicle so wasted, that it could scarcely be felt through the tunica vaginalis, which was loosely distended with fluid. The period of puberty is the time at which varicocele most cemmonly occurs. I have met with very few cases before that age.\nAdi])ose tumours. \u2014 The spermatic cord may be the seat of abnormal depositions of fat. They occur at different parts, as high up","page":1012},{"file":"p1013.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\t1013\nas the inguinal canal, and as low down as the epididymis. In examining the testicles of a young man who died of pleurisy, I found a quantity of fat along the cord, and around the epididymis, and some also beneath the tunica vaginalis covering the posterior part of the testicle. In another case I met with small isolated masses of fat, coupled with a small encysted hydrocele of the cord. When developed in considerable abundance this deposit sometimes forms a tumour either in the groin or in the scrotum. A tumour of this kind in the scrotum has been mistaken for omental hernia. I once dissected a lobulated fatty tumour, surrounded by the thickened sheath of the spermatic cord, on the body of a man upwards of eighty years of age, which was very similar in appearance to a portion of omentum contained in a hernial sac. A mass of fat, however, in the cord may form a more defined and distinct swelling. Such a tumour is preserved in the Museum of the College of Surgeons. (No. 2461.) It is embedded about an inch above the testicle, in the tissues of the spermatic cord and loosely connected with them. Its shape is oval ; it measures four inches in length, and consists of numerous lobes of soft fat, closely held together by their thin fibro-cellular partitions. An interesting case of large fatty tumour in the scrotum, originating in the spermatic cord, was seen by several surgeons, in 1844, much difficulty having been experienced in making out the nature of the swelling. The tumour, together with the testicle, was excised by Mr. Lawrence.* Another of the same character, but of smaller size, subsequently formed in the remains of the cord in the groin, and was excised by me in May, 1849. Collections of fat in the scrotum have been known from the time of Galen by the term steatocele. I suspect that they all originated from the spermatic cord.\nMorbid anatomy of the scrotum. \u2014 The morbid appearances presented by the scrotum, when the seat of oedema, inflammation, and mortification, so closely resemble those of other parts where loose areolar tissue abound, that they require no particular description.\nElephantiasis. \u2014 This disease of the scrotum is rarely seen in Europe, but is of very common occurrence in many other parts of the globe. It consists in a morbid thickening, or hypertrophy of the tissues of which the scrotum is composed. The epidermis becomes thickened, rough as in icthyosis, and intersected with fissures, or chaps. The corium is excessively consolidated, and often nearly an inch in thickness, and very dense. The chief bulk, however, of the tumour, is formed by the conversion of the loose areolar tissue of the scrotum into a large mass of fibrous tissue, infiltrated with a thick jelly-like fluid, evidently albumen, as it coagulates on the ap-\n* Yide accounts of this case by Lawrence, Medical Gazette, May 30. 1845 ; by Brodie, Lectures on Pathology, p. 271. ; by Edwards, and myself, in Provincial Med. and Surg. Journal, June 25. 1845.\nplication of heat, acid, or alochol, and sometimes on cooling after its removal from the body. The areolae of this tissue vary a good deal\" in size, but some of them have been found large enough to admit the extremity of the little finger. Examined in the microscope this structure exhibits the white and yellow elements of the areolar tissue, in some instances mixed with fat cells. When the part is condensed by inflammation, there are often hardened masses in the substance of the tumour, which has a lardaceous appearance when cut, or resembles cartilage ; they sometimes undergo conversion into bone. The testicles are buried in the morbid mass towards its posterior part, but they are usually sound in structure. Occasionally there is a small quantity of serum in the tunica vaginalis. In a case operated on in Calcutta, there was a hydrocele on both sides imbedded in the diseased parts, the largest of which contained between five and six pints of fluid.* The spermatic cords are elongated several inches, owing to the testicles being gradually dragged downwards during the growth of the tumour, but the cords are not otherwise diseased. In the remarkable case of Hoo Loo, a native of China, operated on by Mr, Key, in Guy\u2019s Hospital, the cremaster muscles were nearly as thick as the finger. The morbid growth is not very vascular. Its arteries are derived chiefly from the external pudic and perineal vessels; but these, owing to the magnitude of the tumour, become greatly increased in size. The veins are numerous, large, varicose, and very tortuous.\nThe integuments of the penis are often affected with a similar disease, and enlarge in the same ratio as the scrotum. In cases where the disease is confined to the scrotum, the penis becomes drawn in and ultimately disappears, being completely imbedded in the tumour ; whilst the prepuce being elongated, opens by a navel-like aperture on the anterior surface of the tumour, as may be seen in the subjoined woodcut. In confirmed cases of elephantiasis, the tumour increases until in the course of years it attains an enormous magnitude. As this takes place, the skin is borrowed from the lower part of the abdomen, so that the hair on the pubes becomes thinly scattered on the front and upper part of the tumour. The tumour assumes an oval or pyramidal form, the apex being superior, and is attached to the body by a thick peduncle extending from the pubes, occupying the whole of the perineum, and terminating posteriorly at the verge of the anus. There is scarcely any limit to the size which the tumour may attain. It has been known to acquire such a magnitude as to weigh more than two hundred poundsf, exceeding the weight of the rest of the body. It has been found to measure more than four feet in cir-\n* Calcutta Quarterly Journal, No. 3.\nt Case cited from Eph\u00e9m\u00e9rides d\u2019Allemagne, by Larrey. M\u00e9moires de Chirurgie Militaire, t. ii. p. 115.\n3x3","page":1013},{"file":"p1014.txt","language":"en","ocr_en":"1014\tTESTICLE (ABNORMAL ANATOMY).\n\u00e7umferenee, and almost to reach the ground when the patient is in the upright position. In a case operated on by Clot Bey in Egypt, the morbid mass, which weighed one hundred and ten pounds, kept the patient\u2019s legs far apart, and obliged him to remain constantly on the ground ; it was so bulky that he could even sit upon it. In the accompam ing figure\nFig. 656.\nof a black man, affected with elephantiasis, taken from Dr. Title/s work on \u201c Diseases of the Genitals, in the Male,\u201d the tumour descended nearly to the ankles.\nElephantiasis of the scrotum is a morbid affection of the integuments, analogous to the enlargement of the extremities commonly known by the name of Barbadoes leg ; with which, indeed, in those countries where the disease is prevalent, it is liable to be combined. Elephantiasis of the scrotum, however, grows to a greater size and makes more rapid progress than the same disease in the leg, owing to the very loose texture and depending state of the parts. The labia pudendi of females in warm climates are subject to a similar change, though not to the same extent nor so frequently as the scrotum. This disease appears to be the result of a low form of inflammation of the veins, and to be analogous to the affection termed 'phlegmasia dolens. It is preceded by febrile attacks, attended with pain and heat in the part, and swelling and tenderness of the glands in the groin. After a time, the scrotum continues to enlarge, independently of febrile attacks. In December, 1847, I saw a gentleman, from Barbadoes, who had this disease in the early stage. The whole scrotum was considerably enlarged,\nforming a doughy inelastic swelling, fissured in two or three places. A portion of skin at the root of the penis was a little red and puffy as if affected in a slight degree. The glands in the left groin were enlarged, but those on the right side were unaffected. The testicles were sound.\nHypertrophy of the scrotum is an affection of the same nature as the knotty and lobulated growth of the skin occasionally observed on the nose and in other parts. In this disease the integuments appear as if composed of lobes divided by fissures. In the Museum of St. Bartholomew\u2019s Hospital there is a preparation of this kind, but no history is attached to it. The hypertrophied scrotum appears to have been removed during life. Many years ago I saw a case of the kind at the hospital of La Charit\u00e9 in Paris. The patient was a young man whose scrotum was hypertrophied to about four times its natural size. This disease is liable to be confounded with elephantiasis, but differs from it in the circumstance that the morbid enlargement is entirely confined to the skin, the subcutaneous areolar tissue being unaffected.\nCancer Scroti, or, as it is commonly called, chimney sweeper's cancer, is a disease of the skin, which attacks the scrotum of persons who have been exposed to the contact of soot. It is originally developed in the form of a small pimple or warty excrescence, termed soot-wart, which often remains on the scrotum for months or even years without undergoing any change. Usually, there is only a single wart at the lower part of the scrotum ; sometimes there are two or three of different sizes ; and occasionally they are so numerous and so abundantly and largely developed as to form a considerable cauliflower excrescence. After a time the wart becomes soft, excoriated and red, and exudes a thin irritating discharge, which becoming dry forms an incrustation over the excrescence. After the scab has been picked off, or rubbed offby friction against the dress, ulceration ensues, destroys the wart and produces a painful chronic sore, possessing the ordinary characters of a carcinomatous ulcer on the skin, \u2014 thick, indurated and everted edges, and an irregular excavated base, the surface of which discharges a thin sanious fluid. The ulcer, if suffered to proceed, in-\nFig. 657.\n1 small soot warts ; 2, cancerous ulcer succeeding tlie wart.","page":1014},{"file":"p1015.txt","language":"en","ocr_en":"TESTICLE (ABNORMAL ANATOMY).\ncreases widely, invading the whole scrotum to the perineum, and laying bare the crura penis. At the same time it penetrates deeply to the tunica vaginalis, which becomes firmly connected to the morbid scrotum and adherent to the testicle. This organ may also become involved in the disease, and be the seat of a deep excavated sore. The glands in the groin often enlarge at an early period from irritation ; but at length they become indurated and diseased. The inguinal glands sometimes suppurate, and form intractable ulcers in the groin similar in character to the sore on the scrotum. The ulcer spreads towards its circumference widely and superficially, whilst in the centre it burrows deeply until in many instances it reaches the great vessels of the thigh, destroys their coats, and causes death by haemorrhage. In other cases the glands remain unaffected, but ulceration advances slowly in the direction of the cord, and a frightful sore is produced.\nThe small excrescence in which cancer scroti usually originates is soft, vascular, and sensitive ; and in many respects similar to the soft warts which occur on the internal membrane of the prepuce and on the glans penis. The soot-wart appears, in fact, to consist of a congeries of morbidly enlarged papill\u00e6. The Museum of the London Hospital contains a remarkable specimen of chimney-sweeper\u2019s cancer, in which nearly the whole scrotum is occupied by a cauliflower excrescence, which exhibits these papill\u00e6 in a very advanced state of developement. It was removed from an old man, about sixty-four years of age, who afterwards left the hospital cured. The morbid growth is composed of a number of projecting processes densely grouped together, of variable size, but many very large, with their summits lobulated, expanded, and elevated on narrow peduncles, more or less flattened. They are represented in the subjoined engraving. The soot-wart is sometimes covered with a dense and thick concretion, formed\nFig. 658.\n1015\nby successive layers of incrustation, the superficial still remaining attached, so as to form a projecting elongated conical process, which is not unlike the spur of the cock, and when very long is occasionally twisted like the horn of a ram. Some curious excrescences of this kind are represented in the clever etchings of Mr. Wadd.* The subjoined figure taken\nFig. 659.\nfrom one of them, exhibits the process of its exact size.\nUpon dissecting a portion of scrotum affected with chimney-sweeper\u2019s cancer, the part is found to present very similar appearances to those of carcinoma of the lip. The tissue at the base of the ulcer is dense, indurated, and distinctly laminated, and possesses very little vascularity. On examining some matter scraped from the base of a soot-wart shortly after its removal from the body, I perceived a number of caudate and spindle-shaped nucleated cells. Epithelial cells have likewise been observed in several cases, and the disease is regarded as belonging to the epithelial form of cancer. On examining some diseased lands in the groin in a case of scrotal cancer,\nfound them enlarged and indurated, and composed of a whitish brown or yellowish white substance, mixed up in some places with a soft curd-like matter, or greyish pus, contained in thin white cysts.\nCarcinoma scroti is, with few exceptions, confined to chimney-sweepers ; and the irritating action of the soot on the skin of the scrotum is no doubt its exciting cause. A similar disease occasionally occurs in other parts of the skin, but the scrotum being seldom cleansed and well adapted to harbour soot\n* Cases of Diseased Prepuce and Scrotum, pi. x, xi. xii.\n3 t 4","page":1015},{"file":"p1016.txt","language":"en","ocr_en":"1016\tTESTICLE (ABNORMAL ANATOMY).\nseems more exposed to the disease. Sir James Earle has related the case of a man who had a large sore resembling chimney-sweeper\u2019s cancer which reached from the bend of the wrist to the knuckles, occupying almost the whole of the back of the left hand. The man was a gardener, and for several springs had been in the habit of strewing soot on the ground round the young plants to preserve them from slugs. He carried the soot in an old garden pot which hung on his left hand, while he strewed the soot with his right.\nThe predisposition to cancer scroti appears in some instances to be hereditary. The late Mr. Earle extirpated the testicle and diseased integuments from a sweep aged thirty-five, a patient in St. Bartholomew\u2019s Hospital, whose grandfather, father, and one brother had all perished from the effects of the disease. A father and son were once in St. George\u2019s Hospital at the same time on account of it. Mr. Cusack mentions that he removed a soot-wart from the hand of a female who carried on the business of chimney-sweeping, and that he had previously excised an excrescence of the same nature from the ear of her son.*\nCancer scroti occurs more commonly at the middle period than at any other time of life. In the majority of cases which I have met with the disease occurred between the ages of thirty and forty. Those exposed however to the action of soot may become affected at a much earlier period. Mr. Wadd has figured a diseased prepuce and soot-wart on the scrotum from a boy aged fifteen ; and Sir J. Earle witnessed a case of the disease as early as at eight years of age. It appears that the seeds of this malady are sown in early hfe, but in general do not germinate until they have remained for some time dormant in the system. What is the permanent effect on the scrotum produced by soot, which thus renders it in certain individuals so peculiarly susceptible of a cancerous action at some distant period, we cannot explain ; but that the soot, though the exciting cause of the disease, may in some instances be a remote one, is shown by several striking facts. It is known that persons who have been sweeps when young, but have abandoned the occupation, have afterwards been attacked with chimney-sweeper\u2019s cancer, although they have long been removed from all contact with soot. A sailor between forty and fifty years of age, was admitted into the London Hospital, with an ulcerated sore on the scrotum, presenting all the characters of genuine chimney-sweeper\u2019s cancer. The inguinal glands were indurated and enlarged, and subsequently ulcerated. He had been brought up as a sweep ; but for the last twenty-two years, during which period he had served at sea, he had not been employed amongst soot in any way whatever. The disease first appeared in the scrotum\n* Dublin Journal of Medical Science, vol. xxi p. 137.\nabout three years before. In this case, therefore, the injurious influence of soot must have been exerted nineteen years before the appearance of disease, during which long period he was entirely removed from the effects of its exciting cause. It has sometimes happened, after the morbid parts had been completely extirpated, and the wound healed, the patient having avoided further contact with soot, that the disease has re-appeared as it were afresh, a second and even a third time ; not, however, in the cicatrix of the wound, but on a different part of the scrotum. These, and similar facts, lead to the conclusion that though abandonment of his occupation may render the adult chimney-sweeper less liable to cancer, it by no means forms a satisfactory security against its occurrence.\nCancer scroti chiefly extends its ravages by affecting the contiguous tissues, and has little disposition to contaminate the lymphatic glands or distant parts. An instance is on record of an old chimney-sweeper, who had been subject to this disease for forty years, and had undergone three operations for its removal, yet even then the glands in the groin were unaffected.* A man aged fifty-one who had been a chimney-sweeper ever since the age of seven years, was a patient of mine on account of this disease. He had been repeatedly attacked with it during a period of twenty-two years, and had submitted to no less than five operations for its removal. The glands in one groin became affected only a few months previously. Ulceration took place, and the patient died from its irritative effects on the constitution. On a careful examination of the body, no trace of internal disease could be detected; The cancer was strictly limited to the groin and scrotum. Mr. B. Cooper has likewise recorded a case of chimney-sweeper\u2019s cancer which ended fatally; and on examination none of the glands or viscera of the interior of the body were af-fected.j- These cases show that, when the inguinal glands are indurated, they may be excised with a fair hope of a successful result.\nMelanosis. \u2014 Notwithstanding the dark colour of the skin of the scrotum, melanosis is an exceedingly rare affection of this part. Indeed, the only case of its occurrence there with which I am acquainted, is one that happened in my own practice. The patient was a cabinet-maker, aged thirty-two, and the disease commenced as a small dark spot, apparently produced by some black deposit beneath the epidermis, raising it a little above the surrounding surface. This spot increased until it formed a fungous growth. I excised the part, but the disease re-appeared in the scrotum and in the glands of the groin six months afterwards. It made, however, very slow progress, and did not destroy the patient for six years.J\n* Mr. Hawkin\u2019s Lecture on Tumours. Lond. Med. Gazette, vol. xxi. p. 842.\nf Lond. Med. Gazette, vol. xliii. p. 532.\nj Yide Report of the Case in Lond. Journal of Medicine, vol. i. p. 220.","page":1016},{"file":"p1017.txt","language":"en","ocr_en":"thorax.\nFibrous tumours. \u2014 A small fibrous tumour is occasionally developed in the areolar tissue of the scrotum. It may acquire the size of the testicle, and being firm and of an oval form, resembles a supernumerary gland. 1 have met with only one case of this form of tumour. Dr. Mott, of the United States, excised an enormous mass from the scrotum of a man about seventy-three years of age. The scrotum was twelve to fifteen times its ordinary bulk, and was filled with tumours of a stony hardness, from the size of a nutmeg to that of a large pea. The tumours had all a very white appearance, and the integuments over two or three of the largest, having been ulcerated for upwards of a year, poured forth a foetid discharge, together with a white substance resembling mortar. The disease was upwards of twenty years\u2019 duration. I have no doubt this disease was originally of a fibrous character. The calcareous matter and other changes resemble those occasionally observed in large fibrous tumours of the uterus. A tumour of a similar character and of great size was removed by operation from the scrotum of a man in St. Vincent\u2019s hospital, Dublin, by Dr. O\u2019Ferrall.*\nBibliography.\u2014Anatomy.\u2014De Graaf, DeVir. Organ. Gener. Lugd. Bat. 1668. Monro, Essays and Observations, vol. i. Edinb. 1754 ; also De Testibus et de Semine in variis Animalibus. Diss. Inaug. Smellie. Thes. Med. ii. 317. 1755. Hunter, W. Medical Commentaries, 1762. Warner, An Account of the Testicles, 1774. Palletta, Nova Gubernaculi Testis Hunteriani et Tunic\u00e6 Vaginalis Descriptio, 1777. Brugnoni, De Testium in F\u0153tu positu, &c., 1785. John Hunter, A Description of the Situation of the Testis in the Foetus, with its Descent into the Scrotum, (Animal \u0152conomy), 1786. Seiler, Observ. de Testiculorum ex Abdomine in Scrotum descensu. Lepsi\u00e6, 1817. Wilson, Lectures on the Urinary and Genital Organs, 1821. Sir Astley Cooper, Observations on the Structure of the Testis, 4to., 1830. Lauth, Memoir de la Soci\u00e9t\u00e9 d\u2019Hist. Nat. de Strasbourg, t. i. 1830. Krause, M\u00fcller, Archiv, f\u00fcr Anatomie, 1837. Gulliver, Proceedings of Zoological Society, 1842. Curling, Treatise on the Testis, 1843. E. Huschke, Encyclop\u00e9die Anatomique, t. v. Paris, .1845.\nMorbid Anatomy of the Testicle. \u2014 Pott, On Hydrocele and other Diseases of the Testicle, 1767. Bell, B. On Hydrocele and other Diseases of the Testis, Edinb. 1794. Wolf, L. De Sarcocele, Erlang. 1799. Sir Astley Cooper, Observations on the Diseases of the Testis, 1830. Baring, Ueber den Markschwamm der Hoden, Gotting. 1833. Russell, Observations on the Testicles, 1833. Brodie, Lectures on Diseases of the Testicle, Lond. Med. Gazette, vol. xiii. 1834. Berard, Journal des Connaiss. M\u00e9dieo-Chirurgic. pour l\u2019ann\u00e9e 1835. Velpeau, Diet, de M\u00e9d. t. xv. Landouzy, Du Varicocele, Paris, 1838. Curling, Treatise on the Diseases of the Testis, 1843. Maladies des Testicules \u2014 Biblioth\u00e8que du M\u00e9dicin Practicien, t. iv. Paris, 1846. Vidal (de Cassis), Trait\u00e9 de Pathologie, t. v. 1846.\n(T. B. Curling.)\nTHORAX (Swpal- from Srop\u00e9w to leap, because in it the heart beats). \u201c The habitation of the breathing parts.\u201d \u2014 That part of the human body destined to contain the lungs\n1016\nand heart, and by its movements to maintain the function of respiration.\nGenerally by the term thorax is understood a cavity set apart for the respiratory organs. Such a cavity, however, is not essential to respiration : a respiratory surface only is essential. This must exist in every animal, whilst a separate thorax is found perfect only in mammalia.\nThe development of the respiratory surface may take place in three ways.\n1st. Either towards the interior of the body, in the form of ramified or sacculated cavities ; or,\n2ndiy. Towards the exterior, in the form of lamellated, ramified, pectinated, tufted, ciliated, or pinnated processes called \u201c branchies,\u201d in which Nature seems to have exhausted all imaginable varieties of form ; and,\n3rdly. By a system of tubes ramified to extreme fineness, either in an especial cavity or thorax, or in a cavity common to these organs and to others destined for the digestive function.\nThe movements necessary to respiration, are modified according to the form of the respiratory apparatus and the nature of the medium to be respired, whether pure air or air contained in water.\nIn some of the lowest animals, the respiratory movements are the same as those of locomotion, as in the monad and other infusorial animalcules. In ail animals, even when the respiratory organs are contained in a true thoracic cavity, the frame-work serves other purposes besides that of drawing in and throwing out air ; it gives attachment to the largest muscles of the upper extremity, whether prehensile or locomotive. In man particularly, we find the respiratory muscles contribute to such acts as coughing, sucking, sneezing, yawning, sighing, singing, vomiting, as well as the innumerable articulate sounds of language.\nDistinct respiratory movements, as dependent upon alternate contractions and dilatations of a thoracic cavity, are most regular, or at least, they have been more noticed, in mammiferous animals. The thoracic cavities of mammiferous animals have much of the mechanism of respiration in common. They all possess a vertebral column or spine, and that peculiar frame-work of ribs, together with a sternum, so articulated together as to move in breathing.\nThere is likewise a great similarity of muscular arrangement around the thoracic cavity; and consequently the respiratory movements closely resemble each other.\nAlthough the boundaries of the thorax are generally the parts which move in respiration, and these are generally composed of vertebrae ribs and sternum, yet some animals may have either all of these, or they may lack some of them, or, if present, they may not move in the breathing function. Frogs have a sternum, but no ribs ; serpents have ribs, but no sternum ; tortoises have ribs, vertebrae, and\nDublin Hospital Gazette. Feb. 1845","page":1017},{"file":"p1018.txt","language":"en","ocr_en":"1018\nTHORAX.\nsternum in one mass, rigid and immoveable : the crocodile and lizard have perfect ribs, but their sternum is almost entirely cartilaginous ; and, lastly, in man, the components of the thoracic cavity may have a mobility to command or exceed a space equal to the whole cavity allotted for the respiratory organs. The relative quantity of air which he can respire for the aeration of his blood is probably greater than in any other animal, and his movements are more under the control of his will, and are greatly influenced by mental emotions.\nClassification of the Respiratory Movements in Animals. \u2014 It is not easy to name any particular part in the perfect thorax of the higher vertebrata, which is equally destined for respiratory motion throughout the class. Commonly with ribs and intercostal muscles, we connect the idea of a thorax, or a breathing chamber for respiration ; but a fish has ribs, and likewise intercostal muscles, yet not for any of the purposes of respiration, nor do we acknowledge them to belong to its thorax. A frog has a thorax for respiration with internal lungs, but no ribs, nor, consequently, any intercostal muscles. Nor is a diaphragm necessary to thoracic respiration; for it is mostly absent in birds and reptiles, and quite rudimentary in the few instances (such as the ostrich, crocodile, and chelonia'), in which it is met with. In the chelonia neither ribs, spine, nor sternum are concerned in the respiratory movements.\nThe movements of respiration tend to bring before some surface, air or air contained in water ; or to bring a certain surface continually into a fresh medium, In whatever way this may be accomplished, whether by moving the whole body, or part of the body to and fro, such movements, likewise, are not uniformly for the mere purpose of respiration, i. e. the mere purpose of a\u00ebration. All reptiles take more air into their capacious lungs than they require for oxygenating the blood, particularly in the aquatic kinds (as in the turtle), where the air serves to buoy up their heavy and slow-moving bodies in the dense element they inhabit. Serpents are provided with numerous highly-moveable ribs and powerful intercostal muscles, capable of rapid and extensive inspiration and expiration. They can perfectly distend their body with air. The same may be observed in the chameleon. These volumes of air cannot alone be subservient to respiration, as it cannot all come into contact with the simple undivided respiratory sacs. We see, therefore, there is no necessary relation between the quantity of air an animal may inspire and the extent of respiratory surface. The long hissing sound which serpents produce to alarm their prey, is effected by the expulsion of this great volume of air, by their ribs, through the narrow passages of the nos-\ntrils.\t.\t.\nIn the higher mammiferous animals, we find respiration more especially destined for the chemical purpose of oxygenating the blood.\nHence a more limited quantity is taken in, and it is speedily thrown out again. Large animals make fewer respirations than small ones. According to Scoresby*, the whale breathes four or five times a minute ; the dog, the cat, and rabbit, from twenty to thirty in the same period ; and in small birds the respirations are remarkably rapid.\nWhatever be the form of the aerating organ, \u201c breathing \u201d is accomplished either by, 1st, the weight of the atmosphere rushing into certain cavities, because certain parts of these cavities dilate and threaten a vacuum ; or, 2ndly, by the direct projectile or collapsing force of an organ throwing the ambient element onward. These two ways are generally more or less combined in the same animal. Nor does there appear to be any relation between the grade of the animal and the order of respiratory movement obtained. We notice in the respiration of man a regular inspiration and expiration, two currents in different directions ; and in the lowest animal, the connecting link with the vegetable kingdom, the porifera, or sponge tribe, there are likewise two respiratory currents by distinct channels, which are as regular as the motion of rivers from their source to the ocean, or any other movement depending upon the established order of things. In some species of medusae, there are peculiar sacs on the inferior surface of the body, which, during the expansion of the body, admit water through certain apertures, and again expel it during the succeeding contraction, representing a perfect inspiratory and expiratory action. The complexity, therefore, of respiratory movements does not correspond with the increasing development of the breathing organs. Those animals which have an internal sacculated lung, always retain a certain quantity of the breathing element in \u201c reserve \u201d within their system ; whereas those animals which have external lungs, or gills, have no \u201c reserve \u201d respirable medium. They need none, because where there is an external lung, the ambient element answers the purpose of the \u201creserve\u201d; it is always in contact with the breathing surface. This \u201c reserve,\u201d in mammalia, &c., is not, probably, so necessary to a\u00ebration as for the purpose of ejecting any matter which may obstruct the air passages \u2014 or, in more popular language, for \u201c coughing \u201d up any matter out of the throat.\nThe different kinds of respiratory movement may be arranged as follows ; \u2014\n1.\tInfusorial Animalcules By projectile force.\n2.\tInsects -\tUncertain.\n3.\tFishes -\t-\t- By vacuum & pro-\njectile force.\n4.\tAmphibia\t-\t-\tdo.\tdo.\n5.\tBirds -\t-\t-\tdo.\tdo.\n6.\tMammalia\t-\t-\tdo.\tdo.\nOf the First Kind of Respiratory Movement. Infusoria.\u2014 These animals breathe by a stream propelled in one direction, produced by the ra-\n* El. Physiol. Wagner, 8vo. 1844, p. 670.","page":1018},{"file":"p1019.txt","language":"en","ocr_en":"THORAX.\t1019\npid vibration of hair-like organs \u2014cilia. (Vid. Art. Cilia.)\nOf the Second Species of Respiration. Insects.\u2014 The breathing apparatus in insects generally reaches a high degree of development. Sometimes respiratory tubes or tracheae penetrate every part, in the form of minute ramifying vessels conveying the included air to all the organs. The moving power or means of the renewal of the air in these tubes is at present little known. Some insects, although they live in water (as, for instance, the water beetles, and also water spiders), retain a bubble of air around them ; and, according to Nitzch*, they renew the air in the irtrach\u00e6 by alternately elevating and depressing the an-tenn\u00e6. Beetles, before flying, seem to inflate themselves with air, so as to unfold their wings, which, like other parts of their body, are supplied with air tubes. In this case an inspirative effort must be made by some cavity. Under certain circumstances, bees emit a voice, a shrill sound, which is independent of the motion of the wings, and which appears to be connected with the existence of a current of air through the respiratory tubes or tracheae ; at least, such has been observed when the animal has been irritated and immersed in water, the surface of which, where it was in contact with the orifice of the stigmata at the root of the wing, evidently vibrated at the moment the sound was produced.f\nIn the orthoptera particularly, there are distinct respiratory movements, alternate dilatations and contractions of the abdomen ; in fact, respiratory motions are more distinctly perceptible in this division than in any other insects. In the locusta verrucivora particularly, it is easy to distinguish how the abdominal rings, which have smaller abdominal scuta between them inferiorly, are alternately elevated and depressed exactly like ribs. If we smear the great thoracic stigmata with oil, we find that numerous bubbles of air escape from it during these motions.\nThe organs of respiratory motion, by means of which the supply of air is renewed, present many points of uncertainty. On the one hand, where large stigmata are placed opposite to each other, and connected by tracheae, it is easy to see that alternate opening and shutting of their valves may produce a current capable of renewing the supply of air. It is conceivable also, how, in the orthoptera, lepidoptera, and others, the expansion and contraction of the body, and the elasticity of the air-sacs contained in it, may cause the ingress of air. It is less obvious, however, how the same effect is produced in caterpillars and the larvae of beetles, where a current of air cannot very easily arise from the opposite position of the stigmata, on account of the minute ramifications of the tracheae ; and consequently we must look for some peculiar mechanism, probably cilia, unless we are disposed to admit\n* On the Respiration of the Hydrophil\u00e6, in Reil\u2019s Archiv. B. x. S. 440.\nf Hunter, Philosophical Transactions. 1792.\np. 182.\nthe stagnation of the air in its vessels. Hence it has been conjectured that the dilatation and contraction of the dorsal vessel contributes to this purpose. This, however, appears to be scarcely possible ; and it might be asked on the contrary, if the vermicular motion of the body itself, the sliding of its segments upon each other, are not the means of keeping up the constant ingress and egress of air.*\nIn the lowest of the molluscous class, the external tunic with which they are covered is generally so elastic, that it is capable of dilating by its own properties, when it has been greatly contracted by the muscular coat that is within ; and in forcible expirations, Dr. Grant has observed these animals to contract their muscular coat, and to retract the exterior covering, so as to propel, with considerable impetuosity, and to a distance, the water that fills their respiratory cavity. The elasticity of the tunic tends to overcome the resistance of the muscular coat, and to expand, to a certain extent, the respiratory cavity. Without, therefore, the existence of elastic ligaments, such as we find in conchi-fera, there is a partial means of enlarging the respiratory cavity given to these tunicated animals. This, however, is only in occasional, forced, respiration ; constant and alternate contraction and expansion of the exterior tunic is not met with in any known tunicated, nor in a conchiferous animal, f The streams that enter the respiratory, and pass out of the anal aperture, are smooth, regular, and incessant, and are produced by ciliary movement.\nOf the Third Species of Respiration. Fishes. \u2014 It may be said that the thorax of fishes usually presents four elastic cartilaginous arches, which approximate and separate, open or close the gills, at the same time increasing or diminishing the capacity of the so-formed thorax. These ribs, or branchial arches, support the gills, which are covered by a great flap (operculum) on each side of the base of the skull.\nThe respiratory current enters at the mouth, passes through the fissures on each side of the fauces, and escapes through the branchial openings, placed laterally, covered by the moveable operculum. This stream is uniformly in one direction, \u2014 from before, backwards. It might be asked, why does not the water rush in by the branchial opening when the mouth \u201c threatens\u201d a vacuum ? It will be observed that the margin of the operculum, or great lateral flap, is edged with a delicate membrane, which acts as a valve, this, by the pressure of the water, is forced close round the lateral openings : thus, the water, upon the expansion of the jaws, is prevented entering behind, and consequently rushes in towards the gills by the mouth ; the jaws now close, the operculum immediately opens by the\n* Reimarcus, Ueber das Athmen. in Reil\u2019s Archiv. B. xi. S. 2. ; and Nitzsch, Comment, de Respir\u00e2t, p. 39. et seq.\nf Grant\u2019s Lecture \u201c On the Respiratory Organs of Invertebrata.\u201d Lancet, 1833\u20144, vol. i. p. 964.","page":1019},{"file":"p1020.txt","language":"en","ocr_en":"1020\tTHORAX.\nforce of the jaws contracting with the mouth full of water, which contraction, or expiration, forces the water through the branchial arches and ultimately out by the lateral openings.\nThus the respiration is of a mixed order. The first stage by atmospheric and hydraulic pressure ; the second stage by direct muscular force, similar to that of swallowing.\nIf we cut off the delicate fringe around the operculum the fish is suffocated, the operation being analogous to puncturing the human thorax.\nFishes also possess a power of regulating their respiration. We have watched fishes when in a quiescent state move their respiratory organs so gently that the motion was nearly imperceptible, and at times quite so ; but if at such times you alarm the animal, respiration becomes vigorous, and a comparatively vast body of water rushes past their respiratory organs. The same may be likewise observed when fishes have remained long in a small quantity of water, as if the respiratory movements became more and more vigorous with the deterioration of their element, but give them a fresh supply of water and respiration becomes quiescent again.\nOf the Fourth Species of Respiration. Amphibia.\u2014 In this class there is a gradual development of the animal formation from an aquatic to an aerial being ; so likewise is the aqueous gradually converted into aerial respiration.\nThe respiration of some of these animals is indeed most curious, \u2014 curious as to the very limited quantity of air necessary for their wellbeing, and curious as to whether they have this \u201climited quantity supplied regularly or otherwise. For instance, you may keep an aquatic turtle out of water for days, and it will keep constantly respiring air ; immerse it in water, and it will remain below the surface for half an hour, or an hour, without any inconvenience, and some of these animals will breathe at the surface during the day, and sleep at the bottom alt night without once rising for air, while during the day the same animal cannot remain below above half an hour without showing signs of discomfort. And again, the common tortoise during hybernation breathes so small a quantity of air, that we have never been able to form any calculation of the quantity then respired.\nIn frogs there are no ribs by which the lungs may be moved ; consequently there is no vacuum formed by their thorax during respiration ; they fill the lungs like the tortoise, the newt, the chameleon, &c., by the working of their jaws ; or, in other words, they swallow their air just as we swallow our food. In this respect their respiratory movements resemble those of fishes; the first process being through the agency of external pressure, by making a vacuum with the mouth ; the second, that of forcing, by the operation of the pharvnx. They resemble mammalia in having an internal lung, retaining the air for some time, and in expelling it through the same channel by which it entered. The respiration of the frog has gained attention, and is\nhence better understood than that of many other animals of this class. The following is the mechanism of its respiration, as described particularly by Townson*, though before noticed by Swammerdam and Malpighi. When the broad lingual bone which forms the floor of the mouth is drawn down from the palate by its muscles, the air of the mouth is rarefied, and an additional quantity enters by the nasal apertures, which admit of being closed by valves. The lingual bone is then raised, the nasal apertures are closed, and the air is now forced, or rather sw7allowed, through the rima glottidis into the pulmonary sacs, and can also fill the laryngeal pouches which open into the mouth. Expiration is produced partly by the pressure of the abdominal muscles, and partly by the peculiar muscular power of the pulmonary parietes. To the careless observer the frog does not appear to breathe : it is never seen to open its mouth ; there is no motion of its sides like breathing, and when it is provoked (or rather through fear), though it still keeps its mouth close shut, its sides and back rise, and it blows itself up apparently by some internal power. Upon observing it more narrowly, that skinny and bag-like part of its mouth which is under the jaw, is seen to be in constant motion. While this bag is dilating and contracting, the mouth is never opened to take in new air, but it seems to live all the while on one mouthful of air, and seems to be playing it backwards and forwards between the mouth and lungs. If we now observe the nostrils, a twirling motion, which lets in air at each movement of the jaws, is apparent, corresponding to the quantity of air inspired. If we keep the mouth open we presently see the animal struggle for breath, for we by this means disable the forcing apparatus from propelling the required air into the lungs.\nThe newt breathes with the jaws and nostrils like the frog. It has, like the frog, a constant motion, by short strokes of the bag under the jaw. This bag is formed by the membranes of the mouth, covered and moved by the genio-hyoid and mylo-hyoid muscles. Every minute, or less, it stops, as if intending some particular motion ; then gradually the bag swells out under the lower jaw to a great size ; the contained air is then pressed down into the lungs, and in proportion as the jaws are emptied, the sides of the animal are swelled up. The toad, the chameleon, and the green lizard breathe in the same way, propelling mouthfuls of air down into the lungs. The chameleon can force down a greater or smaller quantity of air, as its needs or fears prompt it. At times it seems to fill its body almost to bursting with air. The tortoise, like the frog, holds its jaws close, and swallows the air ; alternately depressing and elevating the hyoid bone. The first of these motions permits the air to enter the nostrils, when, the tongue immediately closing their internal aperture, the second motion forces the air into the lungs. It is not un-\n* Tracts and Obs. on Nat. Hist., &c, London, 1799.","page":1020},{"file":"p1021.txt","language":"en","ocr_en":"THORAX.\ncommon to notice tortoises yawn ; but how different is their yawning from that of man, who makes, at that time, a deep inspiration, while, in the tortoise, respiration is impassible. We are not prepared exactly to say how the tortoise and turtle expire ; but probably the expiration is performed by the contraction of the abdominal muscles between the lower shield or plastron and the posterior extremities ; for either of these animals can at will, when alarmed, forcibly expel air with a hissing sound, although its shell is unyielding.\nThe most remarkable respiratory movement we have noticed, has been in the common turtle. Sometimes this animal will swell out his hard case, the sternum or plastron yielding to some internal force ; but it is difficult to say by what means this is distended and kept distended.\nIt is clear this animal can gorge itself with air until it cannot sink in water, and that at pleasure it can disgorge itself and fall to the bottom, w'here it lives upon only a fraction of the quantity of air it had just previously expelled.\nOf the Fifth Species of Respiration. Birds. \u2014Here we have a contracting and dilating thorax, with ribs and sternum. The cavity of the chest is not divided by a diaphragm, but is common to the whole digestive organs as well as the lungs ; or, as is said, they are \u201c all chest and no belly.\u201d They differ from all other animals in this respect, that the lungs do not hang in the cavity of the trunk as unattached sacs, but are attached in the form of flattened masses, of spongy, bright red, cellular texture, to the posterior side of the thorax, reaching to the pelvis. They have vesicles or air bags extending through the whole body ; and the cancellated structure of their bones is connected with the true lungs ; so that if we tie the trachea and amputate the wing, leaving the stump of the bone exposed, the bird can inspire and expire through the humerus. In the same manner that the diffusion of air through all parts of the body in insects makes the highest extent of respiration in invertebrata, so also is it with birds among the vertebrata.\nThe sternum and ribs, together with the immoveable range of dorsal vertebrae, all contribute to dilate and narrow the thorax, after the manner of a bellows movement. This dilatation and contraction draws the air through the true lungs, which never move, and immediately the air cells are expanded. By this means two conditions are obtained ; the air is drawn through the lungs for aeration ; and the air filling the cancellated structure, renders the bird specifically lighter.\nThe high flying rapacious bird can thus by a respiratory movement attenuate the air in his body, when soaring in the atmosphere, and again at pleasure condense it in every interstice of his frame, when he drops like a cannon ball, to pounce on his prey ; but immediately before seizing it, again he attenuates the air within him to break his fall ; otherwise he would be dashed to pieces upon the pointed crag, and die along with his victim.\n1021\nThis beautiful provision is wholly due to his respiratory movement, at one time acting as a condensing, and at another time as an exhausting syringe.\nOf the Sixth Species of Respiration. Mammalia.\u2014In this class we first meet with a perfect muscular septum (diaphragm) forming the two cavities of the trunk ; the one for the lungs, and the other for the abdominal viscera. All animals which have a diaphragm, maintain respiration in a manner similar to each other ; for, indeed, it appears that the ouly use of this muscle is to maintain a movement of air \u2014that unceasing pumping to and fro of inspiration and expiration. Their respiration, or at least their inspiration, is purely of the vacuum order.\nThe diaphragm is the chief muscle of ordinary breathing. It can act with great power, protruding the viscera, by its descent, at each ordinary inspiration. This is strikingly seen in animals recumbent and at rest, as in the cow, horse, goat, dog, &c., when it appears as if the animal was breathing with its abdomen. The ribs likewise in some degree maintain respiration in the lower mammiferous animals, particularly in disease. For instance, the respiration of the horse or dog, when the lung is emphysematous, or what is familiarly termed \u201c broken-winded,\u201d is costal, and at such times the respiratory action of the ribs may be beautifully seen.\nIt is most probable that in mammalian respiration we have the highest order of accommodation for peculiar respiration, according to the condition of the animal ; i. e. an instinctive power to respire by different parts of the thoracic cavity, according to the needs of the animal, whether modified by health or disease.\nNearly two hundred years ago, Lower changed the respiratory movements of the dog from diaphragmatic to costal, by paralysing the diaphragm through the medium of the phrenic nerve. {Phil. Tr. Abr., vol. i. p. 179.)\nThe respiration of mammalia is the bellows action \u2014 inflation of the lungs by expansion of the thorax, or inspiration by vacuum, and expiration by propulsion.\nThe projectile force in the respiration of mammalia is nearly all due to mere elastic contractility ; i. e. ordinary expirations are produced by the elasticity of the lungs and ribs, returning backwards, or collapsing, after their distension by the inspiratory muscles. This mere dead and involuntary force performs one half of our respiration.\nMan is not distinguished either by the force, extent, or complexity of his respiratory movements ; he is exceeded in all these particulars by inferior animals. The roar of the lion gives the idea of an overwhelming expiratory power; nor are his lungs less complicated; and the vibration of thousands of cilia, promoting currents around the monad, is more complex than the simple respiratory thoracic action of mammalia. The most striking difference is that produced by mental influence, which appears to command the most delicate modifications of this movement, so indicative","page":1021},{"file":"p1022.txt","language":"en","ocr_en":"THORAX.\nof the passions of his mind, while in the lower animals we see none of these.\nOf the Thorax in Man. Anatomy of the framework of the Thorax.\u2014A portion of the spine, the ribs, the sternum, together with numerous muscles, form the wall of the human thorax. The framework of bones is so arranged as to admit of free mobility in various directions, so as to increase or diminish the cubic capacity of the thoracic cavity..\nOftheDorsal Vertebrae.\u2014That portion of the spine which enters into the composition of the thorax consists of the dorsal vertebrae, which are 12 in number, intermediate in size and position, between the cervical and the lumbar vertebrae. They form the main pillar of support for the whole respiratory apparatus \u2014the great fixed point for the chief respiratory muscles to act against or draw upon. Their general appearance is that of increasing in size from above downwards ; but when carefully examined, they are as two cones, the apices of which touch at about the fourth or fifth vertebra, from which point, in either direction, they increase in their dimensions ; their breadth laterally exceeds their depth from before backwards. Their bodies are large and project deeply into the cavity of the thorax, diminishing greatly the antero-posterior diameter of the chest. Out of twenty cases, the average projection is 2f of an inch, leaving little more than 4 inches for the heart and great blood-vessels.\nA deep sulcus is thus formed, which if a cast be taken of the cavity of the thorax, is very striking. In phthisis pulmonalis, the space between the bodies of these vertebrae and the sternum is sometimes less than one inch ! When the thorax changes its form by disease, this centre pillar is liable to wedge in or jam up the thoracic organs against the walls of the chest.\nThe vertebrae are connected to each other by ligaments, and jointed beautifully into each other, so as collectively to admit of extensive motion, while there is but little movement between any twx> vertebrae.\nOf the bonds of union, the most remarkable are the inter-vertebral disks (ligamenta inter-vertebralia\u2014Weitbr.)\u2014composed of fibro-car-tilage, and placed between the bodies of the vertebrae, each disk serving to unite two vertebrae, and yet to permit a motion in any direction, yielding on that side towards which the column inclines, while on the contrary side it expands with the increasing intervertebral space. This substance is to the brain what the cushion or \u201c buffer \u201d between each railway carriage is to the traveller ; it breaks a sudden jar from being transmitted from carriage to carriage. So does this intervertebral substance soften down any sudden jerk received at the lower extremity of the spine, preventing its being transmitted to the brain in the varied actions of walking, running, and leaping.\nOf the Sternum (os pectoris : Xiphoides), so named from oTepvor, the breast: is a kind of flattened bone, symmetrical in shape, which occupies the anterior and middle part of the\nthorax. It is supported by the ribs on either side ; it is broadest at its upper part, and then narrowed ; it widens again, and finally beconj^s compressed and narrow where it joins the ensiform cartilage. (Fig. 660, e.) Its direction is oblique from above downwards and forwards. This, with the curvature backwards of the spine opposite to it, increases the antero-posterior diameter of the thorax, as may be seen in a lateral view of a cast of the thoracic cavity.\nThe length of the sternum, which is pro-portionably smaller in the female than the male, varies from 5 to ri\\ inches. At the upper part its breadth is from 1^ to 2 inches.\nIts thickness above is about 6 lines ; at its lowest part it is much thinner, never exceeding three lines. The ancients compared the sternum to the sword of a gladiator ; and hence have arisen the denominations given to its various parts : as the handle (manubrium), the body (mucro), the point, or xiphoid appendix, (ensiformis) ; but the last mentioned part now only retains the designation grounded on this circumstance. This division of the bone into three parts has been retained by some modern anatomists, who describe the three pieces of the sternum separately, as so many distinct bones ; we shall only adhere to this in speaking of the development of the bone.\nIn anatomical language it is said, the sternum presents two surfaces, two borders, and two extremities.\nOf the anterior or cutaneous surface of the Sternum. \u2014 This is subcutaneous, slightly convex and affords attachment to the aponeurosis of the peetoralis major and the sterno-cleido-mastoid muscles. It presents three orfourtrans-verse projecting lines, which are traces of the original division of the bone into five pieces. The union between the 1st and 2nd pieces corresponds to the insertion of the 2nd costal cartilage, and is frequently cartilaginous even in the adult age. The line which marks the union of the first two pieces of the bone is the most remarkable : it causes a projection of variable size in different individuals, which has been sometimes mistaken for a fracture or exostosis. At the lower part we sometimes find a foramen ; sometimes in place of the foramen there is a considerable aperture, to which much importance has been attached, as affording a proof of the primitive separation of the bone in the median line. (Fig. 660. d.) The existence of this opening explains how purulent matter deposited behind the sternum may, in certain cases, make its way outwards without any absorption of the bone. This bone is covered by a strong interlacement of very numerous aponeurotic fibres.\nOf the posterior (mediastinal or cardiac) surface.\u2014This is slightly concave, and parallel in direction to the anterior surface. The concavity is directed downwards and backwards, towards the cavity of the thorax, and gives attachment superiorly to the sterno-hyoideus and sterno-thyroideus muscles, inferiorly to the triangularis stemi.","page":1022},{"file":"p1023.txt","language":"en","ocr_en":"THORAX.\n1023\nAlong the middle line, this concavity corresponds with the interval left by the divergence of the two pleur\u00e6 (anterior mediastinum).\nIn the young subject, transverse lines are seen corresponding to those which occupy the anterior surface ; all of these, except the two between the first and second pieces of the bone, are effaced at a more advanced age. This surface is in relation with many organs contained in the chest, and especially the heart, in front of which the sternum forms a kind of shield. This is exemplified, as already noticed, in the frog, which is provided with a sternum, though it has no ribs. At the lower part of the sternum are many nutritient foramina.\nOf the borders of the Sternum. \u2014 These are thick and marked at each side by seven angular depressions for the reception of the cartilages of the first seven ribs, which gives this bone a notched and serrated appearance. These angular cavities are separated from each other by semilunar notches, which are longer above than below, where the facettes closely approach each other. The uppermost of these seven cavities is shallow, triangular, and at an early age becomes ingrained with the cartilage of the first rib ; those which follow are deeper, angular, and situated at the extremities of each of the transverse lines. When examined in the dried specimen, they appear more angular and deeper in proportion to the youth of the subject.\nOf the clavicular extremity.\u2014This is slightly convex, and is the broadest and thickest part of the whole bone. It is slightly excavated from side to side, and presents at each corner a depression for the reception of the sternal end of the clavicle, which bears the name fourchette; this is surrounded with irregularities for the insertion of ligaments. It frequently happens that the two clavicular articulations are not at the same height ; a fact which was noticed by Morgagni, and which Cruveilhier attributes to the unequal wearing of the two articular surfaces. We have once seen the clavicular articulation so low as to unite with the first costal cartilage.\nOf the inferior extremity of the Sternum. \u2014 This is formed by the xiphoid appendix ; or ensiform cartilage, for it often remains cartilaginous to adult age. In length, shape, and direction, it presents numerous varieties ; it is frequently bifid, sometimes pierced by a foramen, and is occasionally bent forwards, or to one side, and in certain cases much depressed : its summit gives attachment to an aponeurotic structure, called the linea alba; behind, it indirectly corresponds with the stomach, which rests upon it when the body is placed in a prone position.\nConnections. \u2014 The sternum articulates with fourteen ribs through the medium of their cartilages, and more directly with the two clavicles.\nStructure of the Sternum. \u2014 This bone consists of two very thin compact laminae, with\nan intervening cancellated structure, the cells of which are very large and have very delicate parietes. Jt is one of the most spongy bones of the body, and it is more than probable that to this circumstance the frequency of disease in it may be attributed. Absorption of this bone and great displacement by bending inwards is very common, particularly in women who wear tight stays. Under such circumstances, or by disease, we have witnessed the sternum so depressed inwards that the depth, including all the thoracic integuments from the spinous processes of the dorsal vertebrae to the anterior surface of this bone, did not exceed three inches, instead of from seven to nine inches.\nOf the Development or Ossification of the Sternum. \u2014 As far as the middle of foetal life or a little later, the sternum is altogether cartilaginous, as represented at a, fig. 660. This\nFig. 660.\nbone is one of the slowest in its ossification ; it exhibits no bony points or centres of ossification up to the sixth month of foetal life. It is also of all bones the one in which the phenomena of ossification proceed with the least regularity. After the sixth month of foetal life, ossification begins with the formation of osseous granides in the middle of the intervals between the points at which the cartilages of the ribs are connected.\n\u201c There are five of these granules for the sternum, exclusive of the ensiform appendage, and they form as many pieces (e, fig. 660.). The process of ossification makes its appearance in the first between the fifth and sixth months ; and, soon following in the second and third, it reaches the fourth at the end of foetal life. The osseous centre of the last varies considerably in the time of its appearance. It may be found soon after birth, and may not be visible for a considerable time (one or two years) after that period.\u201d\n\u201c In many cases, one or more of the divisions of the sternum are formed from more nuclei than one, and there are peculiarities with respect to the number and position of these additional granules which require notice.\u201d\nOssification of the 1 st piece.\u2014This sometimes presents a single nucleus {fig. 660, b 1.), rounded and transversely strong ; sometimes it presents two nuclei, and in this case they","page":1023},{"file":"p1024.txt","language":"en","ocr_en":"1024*\nTHORAX.\nmay be either placed one above the other, or side by side. In the former case the uppermost nucleus is the larger ; in the latter, both may be symmetrical and of equal size, or what is more common, they may be of unequal magnitude. It may occasionally present more than two osseous points. Albinus found three in one subject, and four in another.* Mr.Quain has a preparation in University College, where the very unusual number of six {fig. 660. c. 1'.) are to be seen. In this case, where there is a plurality of osseous points, the largest are generally situated alone; exceptions to this rule are very rare.\nOssification of the body, or the 2nd, 3rd, 4th, and 5th pieces. \u2014 The osseous nuclei which enter into the composition of the body of the sternum have generally a rounded form when they are single, and are situated in the middle line; where they are in pairs or are placed laterally, they are more elongated, but smaller, and appear to represent only the half of one of the single nodules. The second piece has not often more than a single granule {b. 2, c. 2/.), but the rest are frequently formed from two nuclei, which are placed laterally to one another (c 3', 4'.), and not vertically as occurs in the first piece.\nThese different osseous points are always so arranged as to be situated between two costo-sternal articulations, so that a portion of the sternum is developed in each of the intervals comprised between the ribs. The last piece is the only exception, being common to the articulation of the 6th and 7th ribs. There are, therefore, four primitive pieces of the body of the sternum (b. 1, 2, 3, 4.), and each of'these is sometimes formed by one point of ossification ; at other times by two lateral points. The first piece may be formed of one or many ossifie points, which may be arranged vertically as well as laterally To the centres of ossification here described, M. Brechet + has added two small epi-sternal granules, whose position is sufficiently shown by the indication of them, fig. 660. at d**. They occur only at rather advanced periods of life, but they do not appear to be constant.\nUnion of the points of ossification of the body of the Sternum.\u2014In considering the union of the different parts which compose the body of the sternum, it is necessary to make a distinction between the lateral conjunction\u2014that is, the union of the osseous points which are situated on each side of the median line and the vertical conjunction, or the union of the pieces of the sternum properly so called. The lateral conjunction, or the union of these osseous germs, which form a pair in the same interval, always precedes the vertical conjunction.\t. c\nThe vertical conjunction, or the union ot the different pieces of the body of the sternum\n* Cruveilhier, Descrip. Anat. 8vo. 1840. Lond.\nP' fkecherches sur Diff\u00e9rentes Pi\u00e8ces du Squelette des Animaux Vert\u00e9br\u00e9s, &c. m An\"^s des Sciences Naturelles.\u201d 2de Serie, t. 10. (Zoologie) p. 91.\ntogether, commences with the two inferior portions. After this union, the body of the bone consists only of three parts. The 2nd piece then unites with the lower : the sternal foramen is formed sometimes at the junction of these last mentioned parts, sometimes at the place where the two lateral points of the 4th and of the 3rd portions of the body are united. If the interruption to the progress of ossification should occur at the point where the lateral parts of two sternal pieces would meet, the foramen is likely to have considerable size ; for it may\u2019 be the result of an \u201carrest of development\u201d proceeding from four centres each constituting a part. {Fig. 660. d.) The union of the divisions of the body of the sternum takes place precisely in the inverse order of their appearance In fact the appearance of the osseous points proceeds from above downwards, while their union proceeds from below upwards : a fact which verifies the assertion, that the order of development of osseous points is not always correlative to the order of junction.\nThe lowest or 5th piece is joined to the 4th soon after puberty ; the 4th and the 3rd are united, between 20 and 30 years of age ; and the body of the sternum is usually not completed by the junction of the 3rd piece to the 2nd before 35 or 40 years. Lastly, the 1st division does not in general join the rest of the sternum at any period ; but should its union happen to take place, it is only to be met with in advanced age.\nOf the ossification of the appendix.\u2014This is generally accomplished by one nodule. Sometimes there are two ; and then they are rarely symmetrical. The process commences in the upper part of the cartilage, and very rarely extends through the whole. The time of appearance of the osseous point is extremely variable. Sometimes it is visible towards the 3rd or 4th year; sometimes not until the 12th or even the 18th year ; according to the observation of Beclard, between the 2nd and 18th years.\nFrom the 40th to the 50th year, and sometimes later, the appendix becomes united to the body of the sternum. From the varieties of ossification or development of the sternum, it will be evident that it is impossible to assign to it a limited number of osseous points.\nOf thr Ribs.\u2014 The ribs (Cost\u00e6 from custodes *) extend from the dorsal portion of the vertebral column to the sternum, forming arches which correspond to the lateral segments of the chest. About one sixth of the ribs are cartilaginous, and the rest osseous. The osseous portion is the rib properly so called ; the cartilaginous portion is named the costal cartilage.\nThe ribs are 24 in number, 12 on each side ; but cases occasionally occur in which this number is augmented by the addition\n* As if they were guardians of those principal organs of the animal machine, the heart and lungs. \u2014Munro : The Anatomy of the Human Bones, p. 234. Edingb. 1726.","page":1024},{"file":"p1025.txt","language":"en","ocr_en":"THORAX.\t1025\nof a pair of cervical or lumbar ribs : in this case the supernumerary ribs are formed from the anterior parts of the transverse processes of either the seventh cervical or first lumbar vertebra ; which affords a strong proof of the analogy existing between a transverse process and a rib. Sometimes the usual number is diminished to 22 : this is more rarely the case. When this occurs, we sometimes find two adjacent ribs united throughout their entire length. Sometimes the first rib is in a rudimentary state, being properly formed posteriorly, but having its anterior extremity lost among the muscles, or united to the 2nd rib. Mr. Quain has lately seen an instance in which this diminution of the number of the ribs was accompanied with the absence of a dorsal vertebra.*\nClassification of the ribs.\u2014 The ribs are numerically designated 1st, 2nd, 3rd, and so on, counting from above downwards. In the living or in the undissected subject it is easier to count the ribs from below upwards.\nThe seven superior ribs are united by means of their own cartilaginous prolongations (fig. 661. b, c, d, e,f g, and h ; and fig. 662.)\nFig. 661.\nC Jgg|\nto the sternum, and are called true ribs or sternal ribs, or vertebrosternal ribs ; the remaining five are not so immediately prolonged to the sternum, and are denominated false ribs, or asternal ribs, or vertebral ribs.\nWe think it would be more judicious to classify them otherwise, and consider the five superior ribs as sternal, true, or thoracic ribs ; the five next inferior, as diaphragmatic ribs ; the two last, being floating or false ribs. Because, the first five especially encompass the cavity of the thorax ; the five next a portion only of this space, together with a large portion of the abdominal viscera ; and, lastly, because the two last do not touch the sternum through the medium of any cartilage. The transverse shade {fig. 682.) represents the arch\n* Elements of Anatomy by Mr. Quain and W. Sharpey, M. D. London, 8vo. 1843, p. 105.\nVOL. IV.\nof the diaphragm, or the floor of the thorax. Every rib articulates with the dorsal vertebr\u00e6 ;\nFig. 662.\nPosition of the ribs and spine after deep expiration.\nthe spine is their fixed point, or centre of motion, \u2014 the main pillar upon which they act. The superior ten ribs articulate through the medium of cartilages, the first seven through the medium of their own, the next three through that of those of their superior neighbours, {fig. 661.) with the sternum.\nThe ribs have certain general characters which distinguish them from all other bones ; and likewise certain proper or special characters, by which one is known from another.\nI. Of the general characters of the ribs.\u2014The ribs resemble flattened bony hoops, varying in breadth from *4* to *7 of an inch, and from *1 to *4 of an inch in thickness ; they once attain a maximum, and twice a minimum length (fig. 662.)\nThey are of a very irregular shape. Their arch or curve is neither uniform relatively to each other, nor yet relatively to itself at different parts of the bone ; moreover they are twisted in different degrees upon themselves so that the two extremities of the same bone point in different directions, and cannot simultaneously touch an horizontal surface.\nSurfaces. \u2014 These bones present two surfaces : an external or cutaneous surface, which is convex and smooth ; and an internal or pulmonary surface, which is concave and likewise smooth. The anterior end is comparatively flat, the posterior is more cylindrical and truncated, and is rough, particularly at the extremity.\nBorders. \u2014 The ribs have two borders, the one superior, and the other inferior. The superior border is smooth and rounded, and gives attachment to the intercostal muscles ;\n3 u","page":1025},{"file":"p1026.txt","language":"en","ocr_en":"1026\tTHORAX.\nthe inferior border is more thin and sharp, particularly in the middle third, or body, of the bone. This thin or blade-like appearance is caused by a groove on its inner aspect termed sulcus costalis, which is commonly said to be for the lodgment of the intercostal vessels : this border also gives attachment to the intercostal muscles. The borders are irregular in their direction corresponding with the shape of the rib ; which we shall presently notice.\nFig. 663.\nd\nFourth rib.\nExtremities. \u2014 (a) Posterior or vertebral extremity, (fig. 663. c).\u2014 This is rougher and somewhat thicker than the other parts of the rib, and is hence denominated its head (capitulum costce). It presents, except in instances to be presently stated two articular facets, a superior and an inferior one, separated by a well-defined ridge. Each of these facets articulates with a corresponding small surface on the bodies of two vertebrae, the ridge just mentioned corresponding with the intervertebral substance.\nThe head of the rib is supported by a narrow round part, somewhat constricted \u2014 the neck ( fig. 663. /). This is flattened from before backwards and is the weakest part of the bone. Behind the neck there are some inequalities, which correspond to the transverse process of the dorsal vertebra below. Externally to the neck is an eminence known as the tubei'cle of the rib (tuberosity, tuberculum costce, fig. 663. g), which is smooth in one part for its articulation with the transverse process of the lower of the two vertebrae to which the head is connected, and rough in the other, which is posterior, and in some ribs superior to the above, for the insertion of the posterior costo-transverse ligament. The tubercles are most prominent in the four or five superior ribs. Anterior to the tubercle the rib suddenly bends forwards, leaving this part the most convex, making what is termed its angle, (fig. 663. \u00c4) The interval which separates the tuberosity from the angle, is the thickest, roundest, and strongest part of the bone.\n(b) Anterior, or sternal extremity (fig. 663. d). \u2014 The anterior extremity of the ribs is broad, flat, and deeply hollowed out at its tip into an oval pit, into which is implanted the costal cartilage. This extremity of the\nrib is broader and thicker than it is an inch more posteriorly.\nBody. \u2014 This may be described as that part intervening between the angle and the anterior extremity. We have stated that the posterior end is more round than the anterior ; the body, therefore, may be considered as of a transition form, passing from the cylindrical to the flat, blade-like, shape as it approaches towards the sternum.\nCurve. \u2014 The curve which the ribs follow is very irregular, and therefore not easy to describe. No doubt they are of the form best adapted to admit of a great increase of thoracic capacity at_the expense of a remarkably small movement. They appear to encompass the thorax in a somewhat spiral manner (see dark lines figs. 682 and 683.) ; to accomplish which they have three curves, one the common general arch or bend of the bone ; the others the twist of the edges near the extremities termed the curve of torsion.\n(A) Arch or general bend of the ribs. \u2014 This is the most remarkable feature of a rib. Whatever be the curve of the 1st rib, it may be said that each inferior rib describes a curve \u201c one size \u201d larger ; so that one rib can be laid close within the other, like hoops of gradually increasing sizes. Two distinct curves will then be seen. It will be observed that the part extending between the head and the angle describes a larger circle than the angle itself, which as the name implies, is the most acute turn in the bone. More anterior to this, the curve becomes remarkably large ; which Haller has so expressively described as representing the tangent to the posterior curve. In connexion with the general curve of the rib should be noticed two linear measurements, viz., the chord and the versed sine. In fig. 664. is given\nFig. 664.\n-B\t1>\tA\nSecond rib.\nthe 2nd rib ; the line ab is the chord, and D c the versed sine, or a line extending from the chord to the most prominent part of the bend of the bone. The general curve regulates the length of the versed sine.\nThis curve of the rib gives the sides of the chest a power of enlarging,\u2014 a lateral mobility, \u2014 according to the length of the versed sine, and quite distinct from the antero-posterior enlargement, which is according to the length of the chord. The ribs do not increase the lateral dimensions of the thorax by abduction, but solely by their rotation upon the line A n (B) Curves of torsion of the ribs.\u2014If we take","page":1026},{"file":"p1027.txt","language":"en","ocr_en":"THORAX.\t1027\nthe 7th rib and place it on a table it will be observed that the extremities cannot simultaneously rest upon one plane, because it is twisted upon itself. This is due to what is called the curve of torsion. The rib is twisted at each end ; hence a posterior and an anterior torsion. The posterior torsion is most conspicuous, and is therefore more commonly noticed.\n{a) Posterior torsion. \u2014 This torsion is marked at the angle of the rib (h,fig. 663.), particularly upon the convex surface, by an oblique line or a series of faint lines directed from above downwards and forwards. Like other features of the ribs, it passes through gradations, being scarcely perceptible in the 2nd rib, more so in the 3rd, and increasing to the maximum in the 8th, in the 9th and 10th it quickly decreases, until it is lost in the 11th and 12th. The greater the torsion the more distinct is the angle ; where the angle is rudimentary the torsion is imperceptible, as in the 11th and 12th ribs.\nThe degrees of this torsion as it passes through the ribs are most distinctly seen by having the ribs separate, and placing them on a flat surface with their superior edge uppermost, arranging them so that they do not quite touch each other, when the heads of the different ribs will stand up at different heights from the table, forming a somewhat regular wave. This is solely produced by this posterior torsion.\n(b) Anterior torsion. \u2014 Rear the anterior extremity, on the convex surface, in well-developed ribs, we observe an oblique line analogous to that at the angle of the rib, but much less distinctly marked. This line may be considered as forming the anterior angle and corresponding torsion of the ribs, which, like the posterior, is intended for more favourable muscular insertions. Although the anterior angle is comparatively feebly marked, the anterior torsion of the ribs is as well defined as the posterior torsion. It will be seen in fig. 667, that while the posterior extremity of the rib curls upwards, the anterior extremity curls downwards. In like manner as we notice the posterior torsion by placing the separate ribs on a table, so may the anterior torsion be as strikingly seen, taking care to place the ribs upon their superior edge so that the sharp inferior edge is turned upwards. The anterior ends will be seen to stand up in different degrees from the table according to their torsion, commencing with the 3rd or 4th and terminating with the 10th rib.\nArticidations of the ribs. \u2014 The ribs are articulated behind with the dorsal vertebr\u00e6, and in front with the sternum through the medium of the costal cartilages. This has already been noticed under Extremities of the ribs.\nPosition of the ribs. \u2014 The ribs are arranged more or less obliquely, \u2014 about midway between the perpendicular and horizontal (Jigs. 662. and 683.) ; \u2014 and they somewhat\ndiverge from each other as they approach the stern um. (figs. 662. 680. and 681.) Not one of them is horizontal, though commonly represented as if they were. Their position is given in fig. 662. This is important to remember, because we shall see that costal breathing altogether depends upon their obliquity.\nStructure. \u2014 The compact and spongy substances are so distributed throughout the whole length of the ribs that they possess: a certain degree of flexibility, with great power of resistance. In young subjects the compact substance is in excess ; in the aged, and in certain diseases, the opposite is the case ; hence the extreme fragility of these bones, which are then broken by the least effort.\nDevelopment. \u2014 The ribs are amongst the earliest developed bones, ossification commencing in them even somewhat before it has made its appearance in the vertebrae. The deposition of osseous matter extends rapidly throughout them. Each rib (with exceptions to be noticed) is formed from one principal piece ; and two epiphyses. Of these two epiphyses, one forms the head of the rib, and the other the tubercle : their ossification commences between the sixteenth and twentieth years of age ; and they are united to the rest of the bone a few years after, \u2014 about the twenty-fifth year.\nII. Special characters of different ribs.\u2014The differential characters of the ribs, when minutely examined, are well marked ; for, strictly speaking, no two ribs on the same side are of the same shape and dimensions. Although the difference is very small between two contiguous ribs, as, for instance, between the central ribs, i. e. between the 6th, 7th, and 8th, yet it is very conspicuous between those of the top compared with those of the bottom of the thorax. Whatever be the peculiarity under examination, we find it most developed in the 6th or 7th rib ; and below this it becomes less and less marked, until, in the 12th rib, it appears rudimentary. In fact, the 12th rib may be considered little more than a prolonged transverse process j but not so with the 1st rib, which possesses all the marks and uses necessary to the character of a rib.\nThe ribs differ in their length, and in their chord and versed-sine measurements, and consequently in the area of thorax which they encompass. The thoracic dimensions vary considerably in different men and in the two sexes; yet the relative measurements and weight of the ribs will be found useful to our comprehending more perfectly the respiratory movements.\nThese relative measurememts are from a well-formed male thorax. The area-measurement is calculated from an internal, cast of the thorax, cut up slice by slice through each intercostal space. These slices were traced upon paper and measured, giving the absolute area of thoracic cavity encompassed by each pair of ribs, their cartilages, and the sternum. (See^g. 668.)\n3 u 2","page":1027},{"file":"p1028.txt","language":"en","ocr_en":"1028\nTHORAX.\nTable A.\u2014Relative Lengths and Weight of, and Area of Thoracic Space encompassed by, the respective Ribs, including the Space made up by the Sternum and Costal Cartilages.\nRib.\tAbsolute Length.\tChord Length.\tVersed Sine\tArea Sq. In.\tWeight, Grains.\n1\t5*25\t2-00\t1-75\t10-\t98\n2\t9-00\t3-75\t3-00\t27-\t134\n3\t11*00\t5-10\t3-40\t40-\t181\n4\t12-25\t6-00\t3-50\tSI-\t255\n5\t12-50\t6-90\t3*50\t57*\t308\n6\t12-60\t710\t3-50\t63-\t317\n7\t12-25\t7-50\t3-30\t58-5\t391\n8\t12-10\t7-90\t3-25\t43-\t363\n9\t11-50\t7*75\t3-10\t27*\t280\n10\t10-50\t7-00\t2-90\t20-\t216\n11\t8-25\t5-90\t2-25\t10-\t145\n12\t4-50\t3-75\t1-00\t7-5\t60\nFig. 665. represents the above table by curves. The perpendicular lines represent the ribs ; and the curves the characters referred to. By a general view it will be seen that all the lines curve upwards, and are at their highest at about from the 5th to the 9th rib. We shall not treat of particular ribs, but of certain characteristics as they run through the ribs. A knowledge of their shape is necessary to comprehending the respiratory movements in diagnosing thoracic disease.\n1. Length. \u2014 The length of a rib may be taken in three ways, \u2014 its absolute length, chord length, and versed-sine length.\n(a) Absolute length.\u2014In the length from the anterior to the posterior extremity, (a c b,\nfig. 664.) the 12th rib is the shortest. The 11th rib is nearly double the length of the 12th rib ; likewise the 2nd rib is nearly double the length of the 1st rib ; therefore the 1st and 2nd, and the 11th and 12th differ more remarkably in their length than do any of the other ribs. The length (curve a, fig. 665.) suddenly increases up to the 4th rib ; and then the difference is trifling to the 8th rib ; after this the shortening is as rapid as in the four superior ribs.\n(b) Chord length. \u2014 The dotted line b,fig. 665, represents this measurement. This length from tip to tip (a b, fig. 664.) of the rib is the chief modifier of the different apparent mobility of particular ribs. If we allow the range of costal movement to be the same in each rib, while each succeeding rib increases in its chord length, the apparent mobility in different ribs will increase exactly as their chord measurement increases. If a rib be three inches long, and if its free extremity by a given movement passes through one inch of space, the free extremity of a rib six inches long will, with the same absolute movement, pass through two inches. The chord length is an important element in modifying thoracic capacity. It is in this measurement that the 1st rib is the shortest and nearly one half the length of the 2nd rib, \u2014 as 2* is to 3*75. (Table A.)\nThe chord length (line b, fig. 665, compare with line a,) increases and decreases less abruptly than that of the absolute length.\nIf we were to admit that all the ribs at their fulcra possessed the same extent of motion, still the antero-posterior length of the thorax would be unequally increased, and that exactly in relation to the chord measurement ;\nFig. 665.\nAbsolute length a\nChord ' Versed sine\nArea -Weight\nand hence the 7th, 8th, 9th, and 10th ribs advances most, somewhat representing the would advance most. It is a fact that in deep curve line b, fig. 665.\ninspiration the lower part of the sternum (c) Versed Sine Length (d c, fig. 664.) \u2014","page":1028},{"file":"p1029.txt","language":"en","ocr_en":"THORAX.\t1029\nAs the chord length is to the antero-posterior movement, so is this measurement to the lateral movement of the thorax. This is the most uniform measurement in the ribs. If the 1st rib be 1*75, the 2nd rib is to that as 3; and from this rib to the 9th rib, the versed sine never exceeds 3*5 ; hence the curve c, fig. 665. is more horizontal than any of the other curves. So likewise it will be found that the lateral enlargement of the thorax in deep breathing is more uniform than the antero-posterior enlargement. (See dotted line, figs. 711, 712. compared with dotted line, figs. 713, 714.) The space gained by the ribs rotating must be strictly in relation to the length between the deepest part of the arch and the chord line, (d c,fig. 664.) This measurement is greatest relatively in the 2nd rib, and absolutely smallest in the 12th rib, the curve here being very small.\nThe versed sine of the ribs corresponds with the great curve : if a rib were not curved at all, there would be no versed sine. The versed sine does not increase after the 4th rib; and the curvature of the first four ribs forms smaller circles than the rest. The 5th and 6th ribs, although rapidly increasing in absolute length (see Table A.), yet present nearly the same versed sine; and while the chord line increases up to the 9th rib, from the 6th to the 9th the versed sine decreases, showing that the circle or arch of the rib becomes larger as we descend, until the 12th rib, which describes the greatest curve and the shortest versed sine.\nIn fact there is little difference in the versed sine length from the 3rd to the 10th rib, as described by the double line c,fig. 665. This difference of arching of the ribs constitutes the conical form of the thorax, the smaller circles being at the apex, and the larger at the base of the cavity.\n(2)\tWeight. \u2014 The ribs increase not only in their various measurements but also in their weight up to the 7th or 8th where they attain their maximum development. The faint continuous curve, e, fig. 665. is the line of the relative weight.\n(3)\tTorsion of the ribs (special characters}. \u2014We have already mentioned that the ribs have two torsions, an anterior and a pos-rerior. No rib is entirely free from this twist. It is incorrect to believe that the 1st rib is without any torsion, and therefore that the whole rib in its length can touch the same plane. In fact the 1st rib may in one sense be looked upon as the most twisted of all the set, inasmuch as the flat sides which are internal and external in other ribs are in this rib inferior and superior.\nLike other features, the degree of torsion in the different ribs is progressive towards a maximum, and then towards a minimum. The 2nd, 11th, and 12th ribs are most devoid of torsion. In the last two ribs the torsion appears less than it really is, because of their shortness and the large circle which they describe.\nThe two torsions in each rib are always in\ncontrary directions, except in the 2nd rib, where they are both downwards, but the torsion is here very slight. In the 1st rib, as in the ten inferior ribs, they are in contrary directions to each other, so that its two ends cannot touch the same plane at the same time ; but its anterior and posterior torsions are respectively contrary to those of the ten inferior ribs ; its posterior torsion being, like that of the second rib, downwards, and its anterior upwards.\nThe relative torsion of the ribs may be expressed by giving the respective elevations of each extremity from the plane upon which they rest. Thus the posterior torsion is seen when the rib rests upon its inferior edge, and the anterior torsion when it rests upon its superior edge. In this way the following table is calculated.\nTable B. \u2014 Torsions of the Ribs.\nRibs.\tPosterior End Torsion Upwards.\tAnterior End Torsion Downwards.\n1\t6*0*\t5-0f\n2\t2-5*\t3-0\n3\t3*0\t3-0\n4\t12*5\t4-25\n5\t13-0\t12-0\n6\t12-25\t21-5\n7\t18-00\t29'5\n8\t21-25\t28-0\n9\t21-25\t25-0\n10\t9-50\t17-5\n11\t1-50\t5-5\n12\t2-00\t4-5\nIf the posterior twist of the ribs upwards be expressed conjointly as 114, the anterior torsion downwards is 153 ; therefore the anterior torsion is greater than the posterior. The torsions in the 2nd, 3rd, 11th, and 12th are the least ; and they are the greatest in the 7th, 8th, and 9th ribs. Moreover as the torsion increases at one extremity of the rib, for the most part it increases at the other likewise.\nThe ribs of some persons are much less twisted than those of others. This is particularly the case in young subjects before the age of puberty. In infants the torsions are imperceptible ; therefore they increase as we advance to maturity. These torsions afford more favourable traction for the muscles, Where the respiratory movement is most apparent, as from the 4th to the 9th rib, the torsion is highest.\nfc The posterior torsion gives the ribs, when placed in their natural position, a very oblique direction with reference to the spine. This is very important to remember; for the more oblique, the more favourable are they for mobility or for increasing the thoracic cavity. For the same reason the anterior torsion, being in a contrary direction to the posterior, increases still more the obliquity of the rib with refer-* Downwards.\tf Upwards.\n3 u 3","page":1029},{"file":"p1030.txt","language":"en","ocr_en":"1030-\nTHORAX.\nence to the spine. But the relation of these torsions to the spine are different : the posterior torsion is relative to the spine laterally, while the anterior torsion relates to the spine more in the antero-posterior direction : they both conspire to increase the obliquity of the rib in one given direction,\u2014from above downwards.\nThe torsion of the 1st rib, we have noticed, is directed in a contrary direction to that of other ribs ; and we have observed that the presence of torsion in general favours muscular traction : but the 1st rib is an exception to this ; here the torsion exists only between its two chief articulating processes, \u2014 the head and the tubercle : in the other ribs the torsion is between the tubercle and the body of the bone. The posterior torsion of the 1st rib appears to be merely destined to afford the head a more complete attachment to the body of the one vertebra (the 1st dorsal) to which that rib is fixed. A posterior torsion, in this short rib, is not needed for muscular traction, because here the scaleni are placed in the most favourable position \u2014 nearly at an angle of 90\u00b0 with reference to the body of the bone in question, while their other insertion into the cervical vertebrae facilitates the most extensive and favourable means for its mobility, independently of any favouring twist in the rib for that purpose.\n(4)\tSurfaces (special differences). \u2014 The thorax being conical, or somewhat barrelshaped, it follows that the surfaces of the ribs, like the hoops of a very spherical barrel, must gradually change their direction ; thus the surfaces of the 1 st rib are nearly superior and inferior, this bone forming the lid to the thorax, while the surfaces of the 6th or 7th rib are external and internal, and as we proceed downwards to the 10th, 11th, and 12th ribs, the surfaces are again slightly tending towards a superior and inferior position, so that the internal surfaces of the 1st and 12th ribs are directed somewhat towards each other. The body of the rib, or that part which covers the lung laterally, and the anterior and posterior extremities, have also their surfaces inclined in different directions. Thus, take a perfect rib, say the 7th, laterally to the thorax the two surfaces are internal and external, while at the anterior end they are directed \u2014 external surface, forwards and downwards ; internal surface, upwards and backwards ; \u2014at the posterior end, \u2014 external surface, upwards and backwards ; internal surface, downwards and forwards. This is produced by their respective torsions. In some of the lower animals the ribs overlap each other like the tiles of a house; this sometimes threatens in man, particularly in diseases of the spine (fig. 666.), when they closely approach each other.\n(5)\tSpecific differences of the extremities of the ribs. \u2014 The greatest difference is in the posterior end of the rib. The anterior presenting little difference.\n(a) Anterior extremity.\u2014 These are ail hol-\nlowed out for their cartilage. As the ribs become more perfectly developed, for instance, the 5th, 6th, 7th, and 8th, the anterior extremity is broader, but not more deeply hollowed out than some of the other ribs, which are less perfectly developed, as in the 2nd and 3rd, or 11th ribs. This extremity is most pointed in the 12th rib.\nFig. 666.\nRelation of the ribs to the spine in angular curvature.\n(b) Posterior extremity. \u2014 The posterior extremity of the rib is more complicated, and has certain named parts, as the head, neck, tubercle, and angle, all of which become modified as we pass from above downwards. Their differences may briefly be noticed.\nls\u00a3 Of the head.\u2014 On the head of the rib, articulating with the vertebrae, a surface or facet is formed. The 1st, the 11th, and the 12th ribs articulate each with the body of one vertebra, and therefore they have one articulating surface. All the rest articulate each with the bodies of two vertebrae, and they consequently have two such articulating surfaces as already described. The head of the 1st rib is relatively larger than that of the others. For the most part, as the ribs increase in size, the head likewise increases, so that in the best developed rib the head and its surfaces are most perfectly formed, degenerating again to the 12th rib.\n2nd Of the neck. \u2014 The neck being that part of the rib between the articulation of the rib with the bodies of the vertebra, and that with the transverse process, and these points differing but little in their distance from each other in the dorsal vertebrae, it follows that the absolute length of the neck of the different ribs is nearly the same. The necks of the ribs differ in their thickness, accordingly as their respective ribs increase or diminish in size ; therefore, in the middle","page":1030},{"file":"p1031.txt","language":"en","ocr_en":"THORAX.\t1031\nset of ribs, the necks are the thickest and strongest. In the 11th and 12th ribs, the neck, according to our definition, does not exist.\n3rd Of the tubercle. \u2014 As the tubercle articulates with transverse processes, those ribs which have no such articulation have no tubercle ; this is the case in the 11th and 12th ribs. The tubercles are most prominent in the superior ribs, gradually degenerating, or becoming less apparent, down to the 10th, where it is almost rudimentary.\n4th Of the angle. \u2014 In strict anatomical language, the 1st rib has no angle, but the tubercle is very prominent, and gives the bone a very angular appearance, likewise in the 2nd, 3rd, 11th, and 12th ribs the angle is almost imperceptible, whereas it is well marked in the 4th, 5th, 6th, 7th, 8th and 9th ribs.\n(6) Groove (specific differences). \u2014 The groove is not perceptible in the 1st, 11th, and 12th ribs, but distinct in all the intervening ones.\nThe 1st rib has two depressions separated by a tuberosity. The anterior corresponds to the subclavian vein, and the posterior to the artery of the same name.\nCostal cartilages. \u2014 The flexibility and elasticity of the ribs is partly owing to their structure, but more especially to the cartilages which prolong them in front, (figs. 661, 662.) There are twelve costal cartilages distinguished numerically, as 1st, 2nd, 3rd, &c. ; they are separated from each other by intervals which are very considerable at the upper part of the thorax, but gradually diminish as we proceed downwards. It is not very uncommon to meet with thirteen cartilages on one side, and at other times there are only eleven. Sometimes two cartilages are joined, and so aticulate with the sides of the sternum ; when there are thirteen cartilages, the supernumerary one generally exists between the 3rd and 4th ribs ; it is thin, and as it were rudimentary ; it does not form the continuation of any rib, and terminates insensibly in the muscles. The cartilages from the 1st to the 7th articulate immediately with the sternum ; and hence the name of sternal given to ribs with which they are connected. Of the other five cartilages, the last two have no connection with that preceding them ; and from this circumstance, the name floating has been given to the last two ribs.\nGeneral characters oj the costal cartilages. \u2014 All the costal cartilages are flattened like the ribs, and precisely Lresemble in breadth and thickness the bones to which they are attached. The external end is received into a cavity hollowed out in the anterior extremity of the rib; their internal or sternal extremity, which is much narrower than the external, is angular and articulates with the corresponding angular surfaces of the sternum. {fig. 661.) Their anterior or cutaneous surfaces are slightly convex, and covered by the muscles of the anterior region of the trunk, to many of which they give attachment. Their posterior or mediastinal surfaces are slightly concave. Their superior and\ninferior edges bound the intercostal spaces, and give attachment to the intercostal muscles. \u201c They are,\u201d says Cruveilhier, \u201c altogether distinct from articular cartilages, and have a peculiar tendency to ossify, this process taking place partly on the surface, and partly from within outwards.\u201d\nDifferential characters of the costal cartilages.\u2014 The costal cartilages, like the ribs, increase in length, from the 1st to the 7th, and sometimes the 8th, which in this case articulates with the sternum ; from this they diminish in length to the 12th rib When we recollect the conical shape of the thorax this difference is to be accounted for, and moreover, the osseous parts of the upper ribs terminate anteriorly in a line directed obliquely from above downwards and outwards. The sternum is only about half the length of the lateral pectoral space, so that only the first four or five cartilages could join this bone, did not the others turn upwards to reach its sides (fig. 661.), by joining the lower edge of the immediately superior cartilage. The first three cartilages alone, therefore, follow the same direction as the long rib to which they articulate.\nThe first cartilage differs from all the others by its shortness, its thickness, and breadth, and its tendency to ossify ; it is often, but not always, continuous with the sternum.\nThe 2nd and 3rd costal cartilages cannot be distinguished from each other, but they differ from the rest in being joined to the sternum at right angles, in not being bent, and in being as broad at their sternal as at their costal extremities.\nThe 4th cartilage becomes bent upwards, after having followed the direction of the rib for a little way. (fig. 661. e.) The length and the curvature of the cartilages of the 5th, 6th, and 7th ribs progressively increase, and across their intercartilaginous spaces they frequently touch each other. Their inner ends become successively narrowed so as to correspond with the diminishing cavities on the edges of the sternum. The borders of the 5th, 6th, 7th, and 8th costal cartilages articulate together, and present for this purpose articular facets supported by eminences. The cartilages of the 8th, 9th, and 10th ribs gradually diminish in length. Externally they have the same breadth as the rib, and decrease as they pass inwards, so as to terminate by a pointed extremity, which is applied to the lower edge of the cartilage above. The cartilages of the 11th and 12th ribs are extremely short, particularly that of the 12th, which is only a mere tip to the bone, and seldom exceeds four or five lines in length ; their free extremity loses itself, so to speak, in the substance of the abdominal parietes ; so that they are altogether unconnected with the other cartilages.\nLiability of the costal cartilages to ossify. \u2014 The 1st cartilage usually becomes more or less ossified in adult age, and is often anchy-losed to the sternum. After the middle period of life, osseous matter is likewise deposited\n3 u 4","page":1031},{"file":"p1032.txt","language":"en","ocr_en":"1032\nTHORAX.\nto a greater or less extent in the other cartilages, and it is apparent in those of the false, later than in those of the true ribs.\nThese observations apply to the male body ; for in the female the process of ossification does not affect the cartilages until old age has arrived, and it always affects a comparatively small number of cartilages, even if it should happen to extend beyond the 1st, which commonly is not the case.\nOf the ligaments of the ribs. \u2014 The ligaments of the ribs may be divided into three sets, those which connect them, 1st, with the bodies of the vertebrae ; 2ndly, with the transverse processes, and Srdly, with the sternum. The rib is connected with the bodies of two vertebrae (excepting those specified above) forming with each a joint lined with synovial membrane, and held in place by the following ligaments : \u2014\n1st. With the bodies of the vertebra:. \u2014 Costovertebral ligaments, (lig. capitulorum costarum). \u2014 These consist, 1st, of an anterior ligament which connects the head of each rib with the sides of the bodies of the vertebrae. Its fibres, flat and radiated, are divided into three bundles, of which the middle one passes horizontally.for-wards upon the corresponding inter-vertebral cartilage, whilst the superior ascends to the body of the vertebra above it, and the inferior descends tothat below. From the divergence of its fibres this is usually called the stellate ligament. 2ndly, of an inter-articular ligament, a thin and short band of fibres which passes transversely from the ridge separating the two articular surfaces on the head of the rib, to the in ter-vertebral substance, and divides the articulation into two parts, each lined by a separate synovial membrane. This ligament does not exist in the articulation of the 1st, 11th, and 12th ribs, and in consequence there is in them but one synovial membrane.\n2ndly. With the transverse processes of two vertebr\u00e6. \u2014 The rib at its tubercle forms a joint, lined by synovial membrane, with one transverse process ; and to another (being separated from it by a considerable interval), it is connected by ligamentous structure of some length. The costo-transverse ligaments connect the tubercle and neck of the rib with the transverse processes of the vertebrae ; they are named from their position, posterior, middle, and anterior.\na.\tThe posterior costo-transverse ligament\u2014 (lig. transver sum externum costarum, Weitbr.) consists of a very short, thick fasciculus of fibres, which passes from the posterior surface of the summit of the transverse process, to the rough, inarticular part of the tubercle of the rib. Those of the superior rib ascend, those of the inferior rib somewhat descend.\nb.\tThe middle, or interosseous costo-transverse ligament \u2014 consists of a series of very short parallel fibres, which unite the neck of the rib to the anterio surface of the contiguous transverse process. These fibres are best seen by removing horizontally a portion of the rib and transverse process, and forcibly drawing one from the other.\nc.\tThe anterior, or long costo-transverse ligament \u2014 (lig. transversum internum seu cer-vicis costce internum, Weitbr.), is usually divided into two fasciculi of fibres nearly opposite to one another, and on the same plane. They pass from the neck of the rib obliquely upwards and outwards to the lower, margin of the transverse process next above it.\nCharacters peculiar to certain costo-vertebral articulations. \u2014 The articulations of the 1st, 11th, and 12th ribs alone present peculiarities.\na.\tCosto-vertebral articulation of the ls\u00a3 rib. \u2014 The rounded head of the 1st rib is received into a cavity on the side of the body of the 1st dorsal vertebra, the articulation is therefore a species of enarthrosis ; there is neither a costo-vertebral interosseous ligament, nor a superior costo-transverse ligament ; the synovial membrane is much looser than in the'cor-responding articulations of other ribs.\nb.\tCosto-vertebral articulation of the 1 Ith and 12th libs. \u2014 These present the same characters as the preceding, in this respect, that the anterior cavity for the head of the bone is situated upon a single vertebra. The head of the rib, however, is flattened, or very slightly convex. There is no interosseous costovertebral ligament. The superior costo-transverse ligament is much broader and stronger than in the other articulations. As the 11th and 12th ribs have no tubercles, and the transverse processes of the corresponding vertebr\u00e6 are but little developed, it follows that there is no costo-transverse articulation ; but yet there is a costo-transverse interosseous ligament. All these ligaments are much more loose than in the other articulations.\n3rd Ip. With the sternum (Chondro-sternal articulation). \u2014 The costo-sternal articulation is between the angular extremities of the cartilages of the ribs and the corresponding foss\u00e6 in the margins of the sternum ; these articulations are covered and supported by two sets of ligaments. 1st, by an anterior set of ligamentous fibres, thin, scattered, and radiated (ligamenta radiatim disjecta Weitbr.), passing from the extremity of the cartilage to the anterior surface of the sternum, where they interlace with those of the opposite side, and are blended with the aponeurosis of the pectoralis major muscle. 2ndly, by a posterior set of fibres similarly disposed, but not so thick or numerous, connecting the thoracic surfaces of the same parts ; together with some ligamentous fibres placed above, and others below the joint.\nA synovial membrane is interposed be-, tween the ends of each true rib, and the sternum. These membranes can be demonstrated by slicing off' a little of the anterior surface of the sternum and cartilages. Cruveil-hier doubts the existence of such synovial membranes ; we are inclined to differ from him in this respect.\nCharacters peculiar to chondro- or costo-sternal articulations. \u2014 The 1st, 2nd, 6th, and 7th chondro-sternal articulations present the following peculiarities : \u2014\n1st, The cartilage of the 1st rib is some-","page":1032},{"file":"p1033.txt","language":"en","ocr_en":"THORAX.\t1033\ntimes continuous with the sternum, and is sometimes articulated like the cartilages of the other ribs. Cruveilhier found in one subject the 1st rib excessively moveable, because its cartilage, instead of being continuous with the sternum, had its upper edge applied to the side of that bone to which it was united by ligaments, and was ultimately articulated by a narrow extremity immediately above the 2nd rib.\n2ndly. The second cartilage is much more angular at its inner extremity than any of the others : it is received into the retreating angle formed by the union of the first two pieces of the sternum. Sometimes there is an interosseous ligament in this joint, running from the angle of the cartilage to the bottom of the cavity, and there are then two synovial capsules ; in other cases there is only one, but it is always more marked than in the other joints.\nThe articulations of the 6th and 7th cartilages, besides the anterior ligaments, have also a chondro- or costo-xiphoid ligament, more or less strong, which crosses with the ligament of the opposite side in front of the ensiform cartilage, and the lower end of the sternum. Sometimes this ligament only exists for the 7th cartilage ; it is intended not only to strengthen the chondro-sternal articulation, but also to maintain the xiphoid appendix in its place.\nConnection of the ribs with their cartilages. \u2014 The cartilages are almost immoveably united to the ribs, being received into rounded depressions on the ends of the ribs, and their union is maintained only by periosteum, which may be considered to represent their ligaments.\nArticulations of the costal cartilages one with the other. \u2014 Some of the costal cartilages articulate with each other by their edges.\nThe 1st, 2nd, 3rd, 4th, and 5th costal cartilages do not articulate together, unless the aponeurotic lamellae, sometimes very strong, which form the continuation of the external intercostal muscles, and occupy the whole length of the cartilages, be considered as uniting media.\nThe 6th, 7th, and 8th cartilages, frequently the 5th, and sometimes the 9th, present true articulations with one another. Cartilaginous processes arise from the neighbouring edges and come in contact with each other : there are sometimes two articular faces between the 6th and 7th cartilages. The means of union are some vertical fibres united in bundles, so as to form two ligaments, the one anterior and thicker, the other posterior and thinner. The edges of the articulating surfaces, from the 6th to the 8th or 9th, are lined by synovial membrane. The 7th, 8th, and 10th cartilages have not always articular surfaces, but are simply united by vertical ligaments.\nLigaments of the sternum ( Membranes sterni, Weitbr.).\u2014 The pieces of the sternum are connected by a layer of fibro-cartilage, placed between their contiguous borders ; and, on the anterior and posterior surfaces, liga-\nmentous fibres maybe observed running longitudinally, which serve to strengthen their connection. They are sometimes called the anterior and posterior sternal ligaments. The longitudinal fibres are mixed with those radiating from the costal cartilages, especially in front of the sternum, where likewise they blend with the aponeurosis of the pectoral muscles. The anterior portion has thus most of the accessory fibres, and is rough and irregular ; the posterior one is smooth and pearly in its aspect.\nThemuscles of the thorax will be more conveniently noticed hereafter.\nOf the Thorax in general. \u2014 The sternum, the ribs and their cartilages, together with the dorsal vertebrae, are so united together as to compose the frame-work of the thorax, (fig. 662.) Their arrangement is such as collectively to admit of great mobility, and at the same time to protect completely the organs of respiration and the heart. How well adapted this mechanism is for protecting those vital organs is well shown by the impunity with which the prize-fighter receives for many hours the trained blows of his antagonist.\nAlthough the range of motion between each vertebra and the ribs attached to it, is very limited, yet the whole frame-work of the chest enjoys such mobility, that, by a deep inspiration, its capacity is sometimes more than doubled. This bony frame-work is by no means destined solely to cover the respiratory organs, for it extends considerably downwards, composing part of the abdominal walls within which lie the liver, spleen, kidneys, stomach, duodenum, and part of the colon ; hence the distinction between thoracic and diaphragmatic ribs. In fact it will be found that about one half only of the costal surface is destined to compose the thorax. The shade running transversely across the ribs in fig. 632. marks the bottom of the thoracic cavity.\nIn each individual the thoracic cavity corresponds exactly with the volume of the heart and lungs. But there is no relation between the volume of the lungs and the vigour of the constitution\u2014nor between the size of the cavity of the thorax and the amount of air which can be respired, as will be hereafter shown. There is likewise no relation between the volume of the thorax and that of the abdominal cavity. No doubt the vigour of aeration in the lungs is at all times exactly commensurate with the vigour of the alimentary canal, so that the one harmonises with the other ; but this vigour bears no relation to space or size. A small thorax may in some individuals admit of the inspiration of a greater volume of air than a larger thorax in others. In fact it may be commonly noticed that where there is a large abdomen there is generally a small thorax, and that the volume of air which can be expelled at one effort from the lungs of those who have a large abdomen, is less than from those with a small abdomen. The alimentary canal receives at once a given quantity of food, and there it remains for an indefinite time, the thorax large o'\u2019 small, it","page":1033},{"file":"p1034.txt","language":"en","ocr_en":"THORAX.\n1034-\nmatters not which, aerates the blood from this food by movements, quick or slow, long or short ; therefore the respiratory movements only, need be relative to the abdominal cavity, in the same way as the volume of the blast from a pair of bellows is more dependent on their mobility than on their absolute size. The above remarks are applicable to the thorax of either male or female.\nI. Boundaries of the thoracic cavity.\u2014 The thoracic cavity, situated between the shoulders and below the neck, extends but a short way downwards, in the male about seven inches, and in the female about eight inches, beiow the clavicle, so that a horizontal line drawn about an inch below the axilla, corresponds (roughly) with its floor. The floor of the chest, therefore, is much higher up in the trunk of the body than is commonly supposed. The thorax is bounded anteriorly by the sternum and costal cartilages ; laterally by the bodies of the ribs and the intercostal muscles ; posteriorly by the vertebrae and angles of the ribs, and inferiorly by a thin tendinous and fleshy floor\u2014 the diaphragm. The su-rior aperture of the chest is about sixteen inches in circumference, this is the smaller end, and thence called the apex of the thorax. It is bounded laterally by the two 1st ribs, anteriorly by the upper edge of the sternum and inter-articular ligament, and posteriorly by the last cervical and first dorsal vertebrae. The inferior aperture is about thirty or thirty-one inches in circumference, and forms the base of the chest. Anatomists describe this part as bounded in front by the cartilaginous extremity of the sternum or xiphoid cartilage, and the cartilaginous extremities of the last true and false ribs, and more laterally by the 11th and 12th ribs, posteriorly by the last dorsal and first lumbar vertebrae. But as they assume to themselves the privilege of giving a bone a surgical neck as well as an anatomical one, so may we take a similar liberty in describing the thorax for medical purposes. In the examination of the chest during life, too exclusive attention to anatomical boundary has probably led to the error, of regarding the chest as much deeper than it really is, and thence to examining for disease of the lung where really little or no lung exists. A sharp instrument, piercing the chest laterally, at the cartilaginous extremities .of the last true ribs, would most probably penetrate no lung, for the liver, spleen, stomach, &c. are contained within these points. The bottom of the chest is so moveable and so much arched (See art. Diaphragm, Jig. 3.), that in the different stages of inspiration, the lung assumes different positions This may be demonstrated by percussing over the 5th rib at its junction with its cartilage, first after a deep expiration and then after a deep inspiration ; in the latter the sound is \u201c clear,\u201d in the former it is strikingly \u201c dull.\u201d Therefore, instead of taking the insertion of the diaphragm as the bottom of the thorax, it will be found more convenient for examining the chest to take the top of the arch of this muscle\nas the lower thoracic boundary, or the shaded line crossing the ribs in fig. 4., for the medical base. This may be described as corresponding in front with the xiphoid cartilage ; laterally to different osseous portions of the 7th, 8th, 9th, 10th, 11th, and sometimes the 12th rib (fig. 682.), and posteriorly to the 8th and 9th dorsal vertebrae. This will place the bottom of the thorax in a very different position from what is generally supposed ; for, if we express the distance from the 1st rib, to the lowest point of the 10th rib as 13'5, that from the 1st rib to the arch of the diaphragm or medical boundary will be only 6\u201825, less than one half the depth of the thorax as anatomically described. The medical base of the thorax forms a nearly horizontal plane, which extends between the sternum and the bodies of the 9th or 10th dorsal vertebras, its posterior being somewhat higher than its anterior. But on each side of the bodies of the vertebrae there is a deep groove formed by the angles of the ribs. In that part of this groove which extends1 below the above-mentioned inclined plane, a wedge-shaped process of lung is lodged, which varies in size in different subjects, and consequently will be found to terminate at different points in the dorsal region, as already noticed, sometimes hanging down like a broad, thick flap, and at other times forming only an insignificant process.\nIn examining the chest, it is of paramount importance that the student should familiarly know this medical floor of the thorax. The sign laid down by the late Dr. Edwyn Harrison, for marking this boundary, we have found strictly correct in every normal-shaped thorax. Namely, take the xiphoid cartilage as a point to start from, and pass the fiat hand horizontally from thence to the side of the chest, the index finger, when horizontal, will distinguish a slight depression or sulcus at the maximum lateral bulge of the thorax, then from this point slide the hand slightly upwards (perpendicularly), and it will pass over a bulge, about enough to fill the palm of the hand, into another sulcus, better defined than the former one ; this groove corresponds with the medical base of the thorax, and a probe passed in here would graze the arch of the diaphragm after passing through the moveable inferior edges of the lungs. It is necessary that the hand be kept perfectly horizontal, or it will fall into an intercostal space, which does not correspond with the groove in question. With practice, the hand falls at once into the upper sulcus, without first searching for the lower one ; indeed, latterly, Dr. Harrison allowed that the lower sulcus might be absent, and yet the upper one present.\nThis groove is higher upon the right side than upon the left, corresponding to the height of the liver.\nBy external observation, the medical base of the thorax may be known by the slight rotatory motion made upon the diaphragm when a person is walking. A kind of great ball and socket-joint may be conceived to exist between the abdomen and thorax, and the","page":1034},{"file":"p1035.txt","language":"en","ocr_en":"THORAX.\n1035\nouter garments even exhibit a correspondence to this base of the thorax.\nII.\tContents of the thorax. \u2014'Sot only does the thorax contain organs proper to itself, but it lodges and protects others passing to the abdomen ; thus, the food we eat passes through the thorax to enter the stomach, while the eighth nerve both supplies the lungs and then passes onwards to the stomach. Like other cavities, the thorax is lined with a serous membrane (pleura costalis), which likewise invests the lungs (pleura pulmonalis) (See Pleura). The heart and its bloodvessels, the trachea, and the lungs, almost completely fill the thorax. The remaining organs, viz., the origin of the sterno-hyoid and -thyroid muscles, remains of the thymus gland, lymphatic glands, mammary vessels, triangulares sterni muscles, the phrenic, the eighth pair, and the splanchnic nerves, the oesophagus, thoracic duct, vena azygos, and venae cavas, occupy very little space.\nThus the thorax is completely filled. The older anatomists, however, even as late as Benj. Hoadley\u2019s time, considered that there was a considerable space containing air, between the lungs and the walls of the thorax. Now, we know that any considerable accumulation of air in this situation would be destructive ^to the respiratory function.\nIII.\tShape of the thorax.\u2014The shape of the thorax is subject to many varieties which may be conveniently studied under the following headings :\nExternal thorax. \u2014 The thorax in the perfect subject is somewhat conical, broader above than it is below ; but when deprived of the upper extremities and their appendages, the contrary obtains, for it is narrower above than it is below (see figs. 662. and 630. et seq.). Therefore the notion we commonly connect with broad shoulders or broad back, has but a feeble relation with the absolute breadth of the thorax. In fact the diameter of the neck corresponds more correctly with the diameter of the upper part or true apex of the thorax. Freeman the American giant measured 26 inches from tip to tip of his shoulders, while the diameter at the lower part of his neck, in the same direction, was only 6 inches. In women the mamm\u00e6 materially add to the dimensions of the chest towards the apex. We have found the measure of a female round the thorax over the mamm\u00e6 45^ inches, while the root of the neck was 15 inches. Allowing two inches for muscle, &c., the true thoracic apex would not exceed 13 inches, whilst 45^ inches was the apparent circumference of the thorax. The true apex of the thorax is loaded with large muscles, sometimes a vast quantity of fat, the upper extremities, and in the female with large mamm\u00e6 besides. The true bas\u00e9 of the chest is comparatively little covered, particularly below the axilla, where theserrati are seen. This is the weakest and thinnest part of the thorax, but it is well protected by the arms.\n(a)\tThe anterior or sternal region of the tho-\nrax.\u2014In a well-developed thorax the sternum appears to lie in a fossa formed by the pectorales and mamm\u00e6. This region assumes more or less of the perpendicular, according to the carriage of the person ; a perpendicular drawn to the external plane of the sternum would, however, be directed upwards. Laterally to this, the costal cartilages articulate with the sternum ; and, still more laterally, the ribs and their cartilages unite, forming an oblique ridge from above downwards. (See figs. 680. and 681. the line on each side of the sternum.) Still more externally, and parallel to this, may be noticed the projections formed by the anterior angles of the ribs, which bound the anterior region.\n(b)\tThe posterior or vertebral region. \u2014 In the well-developed thorax the spines of the dorsal vertebrae lie in a deep groove formed by the great mass of the erector spinae on either side. These masses extend outwards to about the posterior angles of the ribs, which are nearly in a plane with the spinous processes of the vertebrae, and may be easily distinguished, bounding the posterior region.\n(c)\tThe lateral or costal region is composed of the bodies of the ribs and the intercostal spaces. Much difference has prevailed amongst writers upon various points connected with the ribs, and the spaces between the ribs. Probably this may have arisen from their having made their observations upon the dead subject, wherein the ribs have collapsed to their minimum, or the thorax of a thin subject with the ribs expanded by, perhaps, 200 cubic inches of air, or the ribs when artificially articulated in the clean skeleton, wherein they are generally arranged too wide apart and too horizontal.\nIn the collapsed state of the ribs, i. e. after the most ample expiration by death, we notice\n1st, That the intercostal spaces are not of a uniform width from the vertebras to the sternum. They are most narrow behind, and become wider as they approach the sternum (fig. 680.). The 1st, 2d, and 3rd spaces upon the whole are broader than the five next inferior, and the 10th and 11th spaces are the widest (fig. 682.).\n2dly, Their length differs with the length of the ribs ; thus the two first and two last spaces are the shortest.\n3dly, The position of the intercostal spaces is very oblique (fig. 684.), roughly speaking, about mid-way between the horizontal and the perpendicular.\n4thly, They are moveable, and in the different stages of respiration they can assume different positions and different perpendicular widths.\nIt has been found necessary for the convenience of auscultation, to subdivide the thorax more minutely. The subdivision proposed by Laennec has been generally adopted, although some of the terms, like those of the respiratory sounds, have been modified by writers of later date.\nThe anterior and lateral superior division,","page":1035},{"file":"p1036.txt","language":"en","ocr_en":"1036\nTHORAX.\nTable C. \u2014 Thoracic Regions.\nREGION.\nAnterior :\nClavicular (subclavian of Laennec) -Infra-clavian (anterior superior of Laennec) Mammary ------\nInfra-mammary (sub-mammary of Laennec)\nSternal \u2014 superior, middle, inferior -Lateral:\nAxillary ------\nI nfra-axillary (lateral of Laennec) -Inferior-lateral -\t-\t-\t-\t-\nAcromial ------\nPosterior :\nScapular, upper and lower Interscapular ------\nInfra-scapular (inferior dorsal of Laennec)\ngive the clearest sound upon percussion, and the back the least clear. Below Harrison\u2019s line, there is little or no evidence, from percussion, of the presence of lung, except in deep inspiration, and then the sound on percussion is mixed with other sounds from the abdominal organs. Only a small part of the mammary region covers lung, scarcely any being subjacent to the anterior parts of the 6th,\u00b07th, and 8th ribs. (See fig. 4, wherein a transverse shading indicates the diaphragm. ) Internal conformation of the thorax. \u2014 To comprehend clearly the internal shape of the thorax, it is necessary to take a cast of this cavity. This may be done by making an opening in the sternal region, just large enough to admit the hand to remove the heart and lungs, filling up the whole of the cavity with plaster of Paris and returning the sternum, then opening the abdomen, cutting away the diaphragm, and so removing the cast, which <rives us a clear knowledge of the internal conformation, and every kind of measurement correctly. (Fig. 667. is a cast from the cavity of figs'. 680\u2014685, \u2014 male subject.) We have stated that the perfect thorax viewed externally, and the same when the superficial muscles and upper extremities are removed, differ widely in their relative form. The thoracic cavity likewise differs remarkably from either of these views. The general view is that of a cone, but broader from side to side than from before backwards: therefore the cone is somewhat flattened.\n(a) Anterior region. \u2014 This very closely resembles the anterior region of the external surface, being convex in its form, precisely corresponding with the concave sternum. The upper part, immediately behind the superior end of the sternum, is rather concave {fig. 667 ). At this part the cavity divides into two small cones, for the reception of the\nSITUATION.\nPortion covered by the clavicle.\nBetween the clavicle and 4th rib inclusive. Between the 4th and 8th ribs.\nFrom the 8th rib to the cartilaginous border of false ribs.\nOver the respective parts of the sternum.\nAll the axilla to the 4th rib inclusive.\nBetween the 4th and 8th ribs at the side.\nBelow the 8th to the false ribs inclusive.\nBetween the clavicle, neck of humerus, and along the upper margin of scapula, including the root of the neck.\nSupra-spinous fossa and infra-spinous fossa.\nBetween the inner margin of scapulae.\nBelow inferior angle of scapula and border of serrati to the level of 12th vertebra.\nright and left apices of the lungs, which ascend upwards to a variable height, \u2014 an inch or an inch and a half. Both apices of the lungs are directed from below, upwards\nFig. 667.\na\nCast of the cavity of the thorax represented in figs.\n1, 2, 3, 4, 5, and 6.\nand forwards; it is incorrect to consider them as directed backwards ( fig. 667. a, which is the left apex seen above the 1st rib.) In some cases, particularly where the lung presents a puckered appearance, the axis of the apex is inclined nearly to the horizontal, and at all times it is about perpendicular to the sternum. These apices, throughout advancing life, are tending to incline forwards ; it is this portion above the 1st rib (fig. 667.), which is so vulnerable in phthisis pulmonalis. There is great difference in the precise character of these apices in different individuals ; in fact we have seen no two the same ; some are remarkably truncated, and broad from before backwards ; others are thin in this direction, and pointed ; some obtuse and low, others acute and high. They have the","page":1036},{"file":"p1037.txt","language":"en","ocr_en":"THORAX.\n1037\nsame characters in both sexes. There is little difference in the height of the two apices. The elevation of the liver on the right side does not necessarily cause the right apex to be the higher. The right lung is more shallow than the left; but this is not because it is \u201c pushed up,\u201d but because, in order to accommodate the liver, there is less lung-substance on the right side. If the mean of a series of observations represents the right side of the thoracic cavity as equal to 151, the left may be given as 182. The same may be said of both sexes.\n(b)\tPosterior region. \u2014 If we examine this region upon a cast of the thoracic cavity, we observe in the middle line a deep fossa, formed by the projection, to the very centre of the thoracic cavity, of the bodies of the dorsal vertebrae.\nThis fossa is wider towards the base of the thorax, as may be seen by comparing the different sections of the cast (compare the notches, 10, 11, and 12, with those of 3,4, and 5 in fig. 668.).\nFig. 668. ;\nSections of a cast of the thorax showing the space encompassed by each pair of ribs respectively.\nThe bodies of the thoracic vertebrae, form almost a complete septum ; they are certainly a central column of support for the whole trunk of the body, bearing an equal distribution of the superincumbent weight in all\ndirections. There is no part of the skeleton which more strikingly demonstrates that man was destined for the erect posture, than this central position, together with the increasing dimensions from above downwards, of the vertebral column. These conditions exist only in the human subject. The groove in the cast formed by the dorsal vertebrae is directed upwards and fonuards, so that at the apex of the thoracic cavity it completely divides the lungs, producing two little cones laterally for the lungs, forming the right and left apex.\nAt the base of the thorax this perpendicular column again completely divides the lower lobes of the two lungs. The shape of the posterior part of the cast is that of a curve directed upwards, and sharply forwards, near the apex (j\u00a3g.667.). This curve near the apex is, like the form of the apices, ,very various.\nAn inflated lung assumes the same shape as this cast, giving even the marks of the ribs. The student, in order to have a correct idea of the lungs, should remove them from the body with the heart attached ; then inflate them to their utmost, when their shape, their lobes, and relative mass before and behind, are clearly seen.\nIf now we inspect the cavity of the thorax itself, we find that the bodies of the vertebrae by their projection as above described, divide the posterior portion of the chest into two vast lateral grooves, which lodge the posterior portions of the lungs; these two grooves, partaking of the form of the thorax, are consequently conical in their configuration. They lodge fully one half of the entire lungs. This is worthy of remembering in reference to diagnosis, particularly when pneumonia is suspected ; in such cases auscultation of the dorsal region demands as much attention as that of the anterior region. Though less vulnerable to phthisis pulmonalis, yet it may lodge disease in parts comparatively remote, and where inflammation may insidiously gain serious ground upon the patient, particularly in children.\n(c)\tLateral region. \u2014 This precisely corresponds with the external lateral view of the thorax (compare fig. 667. with fig. 680.); it presents indentation of the ribs, resembling a diagonal, curved, grate.\n(d)\tThe base of the thoracic cavity has been described above.\nConformation as affected by age and sex. \u2014 Age alters the conformation of the chest. In the earlier periods of existence the thorax is the smallest of the three great cavities, probably from the inactivity of the lungs! In the f\u0153tal thorax the antero-posterior diameter exceeds the transverse diameter, the sternum projecting forwards, and the heart and thymus gjand filling up the middle of the cavity. The ribs in f\u0153tal life are less curved, and consequently those deep grooves, seen in the interior of the chest on each side the spine, formed by the angle of the ribs, so conspicuous in after life, are almost wanting ; the vertical depth also is much less at this period, because the lungs are unexpanded and unemployed, while the abdominal viscera, particularly the","page":1037},{"file":"p1038.txt","language":"en","ocr_en":"1038\nTHORAX.\nlarge liver, are in activity and pushing up the diaphragm. The superior opening or true apex is greater from before backwards than transversely, which is the very contrary to the adult conformation. The inferior or true base of the thorax is extremely wide in every direction, from the encroachment of the abdominal viscera. At birth the thorax suddenly enlarges, by the air expanding the lungs to two or three times their previous cubic dimensions. As age increases, the curvatures of the ribs increase, and, with the vertebrae, running up through the very centre of the thorax, form the two great lateral grooves, peculiar to man, for lodging the chief bulk of the lungs. The depth of the thorax is diminished, while its breadth is increased, and this participates in that more perfect development of the system at the age of puberty. It is at this time that malformation of the chest frequently becomes obvious, particularly in females. In the adult age the thorax still grows, but in a degree less apparent, until it assumes the form of what is termed an open chest, capable of expanding in any direction, supplying us with air under violent exercise, and resisting severe blows. As agq advances, through the decline of life, the thorax has a tendency to collapse ; the bony framework threatens to unite into one rigid cage, the true apex droops forward, the shoulders appear higher, and the round back of old age becomes apparent, so that we may make a tolerable guess at the age of an individual by the conformation of the back. The erect thorax is absolutely necessary to healthy vigour, while the drooping-forward chest is always accompanied with proportionate feebleness.\nSex. \u2014 The chief difference of external conformation between the sexes is due to the largeness of the mammae, and the less width across the shoulders in women than in men. There is no distinguishing the sexes by the internal form of the thorax, they so perfectly resemble each other. The chest of the female is only absolutely smaller, but not always that, certainly not relatively so, The nipples are not uniformly in the same position ; those of the female are generally closer together than those of the male.\nConformation of the thorax affected by disease and occupation. \u2014 The conformation of the thorax chiefly depends upon the healthy condition of the main pillar of support, the spine ; but not always so, for that deformity called \u201c chicken breast \u201d appears to be independent of the condition of the spine. And, again, emphysema of the lungs tends to protrude the ribs and advance the sternum.\nDisease, as caries of the vertebrae, or an atonic condition of the thoracic muscles, owing to which the spinal column may yield, either laterally, producing \u201c lateral curvature,\u201d or anteriorly, giving \u201c angular curvature,\u201d produces the most marked distortion of this pillar of support, and consequently of the whole thorax. In youth, particularly in females, (from the present system of education,) the spinal column,\nwhich is at all times sufficiently flexible, bend\u00e0 under the weight of the head and arms ; and for want of proper exercise the muscles of the back become enfeebled, and unable to restore it to the erect position. When \u201c rickets\u201d attack the spine, it may curve in any direction, compressing the ribs and projecting the sternum. It is surprising to witness to what an extent of deformity the thorax may attain, and yet life still remain (see fig. 666., where costal respiration could not exist ; and where all the abdominal viscera must have been forced up into the cavity of the thorax, for the 10th rib is nearly touching the crista of the ilium). We have noticed a case where such was the effort of nature to preserve the thoracic and spinal cavities, that life was maintained in a boy 14 years of age, though 7 bodies of dorsal vertebr\u00e6 were completely absorbed.\nIn emphysema of the lungs, the sternum is protruded, and the antero-posterior diameter of the thorax is increased sometimes by an inch, the shoulders are raised, and the person assumes always the form of a man who has made the deepest inspiration.\nIn phthisis pulmonalis, the thorax changes its form, which is manifested by the shoulders inclining forwards, the anterior and superior parts bending in the same direction ; the otherwise round full apex becomes flattened, collapsing upon itself ; and there is an incapacity to extend the apex ; this is a sure and delicate test of that disease threatening, before any symptoms can be detected by auscultation. In other stages there is a loss of symmetry in the sides. In pleuritic effusion or in empyema, one side may be full and immovable, whilst the other has to perform the respiratory functions. In fact, disease of the respiratory organs may produce a change in the form of the thorax, either downwards, upwards, or outwards, or by collapse of the apex.\nFrequently repeated or permanent compression, may produce many varieties of conformation of the thorax. Cruveilhier observes that infants, in whom the thorax was perfectly well formed at birth, have become deformed and flattened on the sides of the thorax, by pressure from the hands of the nurse. Slight external pressure in early life may be productive of permanent deformity of the thorax, The effect of strong and permanent constriction, as from tight stays, occasions a distortion in the form of the chest. This kind of compression principally affects the lower part of the thorax ; so that the 5th, 6th, 7th, 8th, 9th, and 10th ribs are pressed forwards and inwards, because the length of their cartilages allow them to yield readily : and the viscera corresponding to these ribs, also undergo alteration in their position and figure, encroaching upon the thoracic cavity, compressing the lungs upwards, into the apices of the chest. The imprudent custom of females wearing a hard unyielding piece of wood, steel, or whalebone up the front of their corset, commonly produces a compression inwards of","page":1038},{"file":"p1039.txt","language":"en","ocr_en":"THORAX.\t1039\nthe sternum. We once noticed a case where the sternum was forced inwards to such an extent, that the entire depth of the thorax, by external measurement, from the middle of the sternum to the corresponding part of the back, only measured 2 inches instead of 8 or 9 inches !\nOccupation likewise modifies the form of -the thorax. The clerk who writes many hours at the desk, carries himself differently to the soldier. Coal-miners have stooping chests when they work in districts where the coal seam is thin, and the roof consequently low, as in the north of England. In fact, all trades or occupations which require stooping for many hours together, tend to injure and malform the chest.\nPigeon-or chicken-breast.\u2014This is a malformation quite distinct from any of the above mentioned, always affecting the sternal region in particular. An explanation of this curious disease has attracted the attention of Mr. Shaw, to whom we . are indebted for the following remarks.* He noticed the effects produced upon the thorax by violent efforts of breathing in a child with croup. If we watch, says Mr. Shaw, the motions of the thorax in a young patient who is in danger of suffocation from an obstruction in the wind-pipe, we shall perceive that at each inspiration, while the superior ribs and sternum are raised and protruded as in common costal breathing, the lower ribs are, at first, flattened, and then drawn inwards, so as to produce a deep indentation on both sides. The depression is greatest in the line of junction of the ribs with their cartilages ; it is as if a band had been tied tightly round the waist, or resembles the indentation near the margin of the chest, often seen in women from tight lacing. The constriction lasts during inspiration ; in expiration, the ribs by their elasticity flap out and recover their form. That the lower ribs should be drawn inwards in the act of inspiration, diminishing the area of the chest at a time when their natural motion should enlarge it, will be understood by considering the relative conditions of the thorax and the lungs in the laboured respiration which arises from obstruction in the wind-pipe. Under the sense of impending suffocation, the young patient instinctively struggles to enlarge the cavity of the chest to its greatest capacity ; but, while that effort is making, the quantity of air that passes into the lungs is very small, because of the obstruction in the larynx or trachea : a portion of air may reach the air-cells at the apex where the bronchial tubes are short, but little or none penetrates so far as the base of the lungs ; consequently the lungs are imperfectly dilated. If the child succeed in enlarging the area of the chest in proportion to its powerful efforts, while the lungs were at the same time but partially dilated, it would follow that a vacuum would be produced in the space between the\n* Deformity of the Chest from Dyspnoea, Oct. 1841. Lond. Med. Gaz. New Series, vol. i. 1842.\nparietes of the thorax and lungs. But owing to the great flexibility of the ribs near the lower margin of the thorax in childhood, the atmospheric pressure overcomes the action of the muscles, and thrusts in the sides so as to preserve the balance of the air within and that without : in common language, the walls of the chest on each side are \u201c sucked \u201d inwards, like the valve in a pair of bellows.\nWhen we look at the general shape of the chest during the continuation of the constriction, we perceive at once a resemblance to the pigeon-breast deformity ; there is in both the same protrusion of the sternum, and the same depression of the cartilages on each side.\nThe question therefore arises, can the deformity have a similar origin to the change in the figure of the chest which is caused by difficult respiration ? Dupuytren wrote a memoir upon this form of distortion, and he has shown that difficult respiration and pigeon-breast deformity are frequently associated together, so that he has almost constantly found that patients who are pigeon-breasted have at the same time enlargement of the tonsils ; but Dupuytren does not profess to explain why the two complaints should go together. Some years ago Mr. Shaw had under his care a little boy with greatly enlarged tonsils, which were very low down in the throat, owing, as it appeared, to their having got within the grasp of the constrictor muscles, of the pharynx. He had constant dyspnoea, and occasional fits of suffocation, in one of which Mr. Shaw performed laryngotomy: on his admission into the hospital, and for several weeks afterwards, it was observed that he had the \u201cpigeon-breast\u201d form of chest; but after his tonsils were excised, and his breathing had been perfectly free for some time, the sternum subsided to its proper level, and the thorax recovered its natural shape. These facts prove that a connection, like cause and effect, exists between obstruction of the air passages and pigeon-breast deformity. It is not necessary that such impediments should be so great as to produce strongly marked symptoms of dyspnoea ; for, while the distortion is being produced the child is growing,\u2014both the size and shape of the chest are undergoing a natural change. Mr. Shaw justly considers it quite possible that a cause which may have very slight influence in changing the figure of the thorax, if operating only for a week or a month, will, if continued longer, disturb and modify the process of growth ; so that after intervals of half-years or years, a decided effect will be exhibited in the form of the chest. It is not impossible that continued disease in the air passages of children, which may fail to attract much attention, or at least may not be thought capable of producing distortion, may nevertheless gradually and insidiously give rise to the permanent deformity of \u201c pigeon-breast.\u201d Mr. Shaw particularly refers to enlargement of the tonsils, attended even with slight inconvenience; to enlargement of the lymphatic","page":1039},{"file":"p1040.txt","language":"en","ocr_en":"1010\tTHORAX.\nglands in the course of the trachea or bronchi ; to pressure upon the trachea by the thymus gland, when later than natural in being absorbed, or when hypertrophied ; and to morbid thickening of the mucous membrane of the larynx, or of the trachea and bronchi succeeding croup or cynanche pharyngea. We concur with these views upon this subject, the more so as we likewise have noticed the pigeon-breast in children where enlarged tonsils have been present. We must not imagine from this that, where there is dyspnoea, there we shall always find the deformity in question ; for difficult breathing may be caused by other circumstances than those which disturb the counter-pressure of the atmosphere in the thorax.\nIV. Dimensions of the thorax.\u2014The measurement of the thorax may be considered externally and internally; and, what is most remarkable, the one class of measurements may not have any relation to the other class. Moreover, the external measurements bear a certain proportion to the whole frame, whilst the internal do not.\t1\n(a) External measurements of the thorax.\u2014\u2022 The external dimensions of the thorax differ much in different men ; this is obvious to all. There is the broad-chested and the narrow-chested man. Mr. Brent has calculated, from an extensive number of observations, the following proportions, which we arrange thus :\u2014\nTable D.\u2014Relation of the External Chest to the\tHeight,\tmeasured over the Nipples.\nMinimum chest :\t\u00a3 of the stature \u2014\tof the\tstature\t= circumference of chest.\nMedium chest :\t*\tof\tthe stature\tof the\tstature\t= circumference of chest.\nMaximum chest :\t* of the stature =\tcircumference of\tchest.\nFor example, let us suppose a height of 61 inches, as follows,\u2014\nMinimum chest : height 61 in., * = 30'5 in. \u2014 gV = 29*5 in. circumference of chest. Medium chest: height 61 in., * = 30-5 in. + f-g (= 4\u201807) = 34\"57 in. circumference of chest. Maximum chest : height 61 in., * = 40'7 in. = circumference of chest.\nThus, by taking the most perfectly proportioned chests, either from living figures or from the classical athlet\u00e6 of ancient sculptures, the following is the result.\nTable E. \u2014 External Thoracic Dimensions, (in three classes according to weight) in relation to the height, obtained from calculation.\nMALES :\t\tCIRCUMFERENCE OF THORAX.\t\t\nHeight.\t\tMinimum Weight.\tMedium Weight.\tMaximum Weight.\nFt.\tIn.\tInches.\tInches.\tInches.\n5\t0\t29*\t34\t37*\n5\t1\t30*\t34*\t37*\n5\t2\t30*\t35*\t38*\n5\t3\t3H\t35*\t39\n5\t4\t31*\t36*\t39*\n5\t5\t32*\t37\t40*\n5\t6\t32*\t37*\t40*\n5\t7\t33*\t38*\t41*\n5\t8\t33*\t38*\t42*\n5\t9\t34*\t39*\t42*\n5\t10\t34*\t39*\t43*\n5\t11\t35*\t40*\t44\n6\t0\t35*\t40*\t44*\nFrom this the minimum chests increase on an average nearly f (3'9), the medium chests rather more than * (4'2), and the maximum * of an inch for every increasing inch of stature. We have found from observation, upon 1276 cases of all various classes conjoined, a regular arithmetical progression of the thoracic circumference over the nipples in relation to weight.\nBy the total mean of our observations the chest increases exactly one inch for every 10 lbs. increase of weight, sinking the effect of height, which, however, cannot well be omitted,\nbecause, as a general rule, the height increases with the weight.\nMr. Brent has found that twice the breadth of the shoulders equals the circumference of the thorax over the nipples \u2014 i. e. from point to point, or the caliber of the broadest part of the shoulders. Thus, if the caliber be 18 inches, the thorax will be 36 inches in circumference. Four times the distance between the nipples is equal to the circumference. Four times the antero-posterior diameter is equal to the circumference : therefore the distance between the nipples is equal to the depth from before backwards of the external thorax. At the height of 5 feet 9 inches this antero-posterior diameter varies from 7* inch, to 12* inches.\n(b) Internal measurement of the thoracic cavity.\u2014Before entering info details we may observe, that the thoracic cavity is much smaller than we might, perhaps, be led to expect ; that the depth from above downwards is, when compared with the body, very shallow. It is, however, capable of enormous dilatation or mobility, even to 100 per cent ; 80 per cent is common.\nThe absolute dimensions of the thoracic cavity offemales are obviously smaller than those of males, because they are altogether of smaller conformation, both in stature and weight; but, relatively, the difference is probably little, Although the proportion of some of the diameters may differ, yet that of the total cubic measurements appears not to do so.\nA certain rude relation of necessity must exist between the size of a man and the dimensions of his thoracic cavity. A man 7 feet high will have a larger chest than one 5 feet or 6 feet high. But there is no constant and uniform relation of the size of the chest, either to the height or weight of","page":1040},{"file":"p1041.txt","language":"en","ocr_en":"THORAX.\n1041\nthe body. The function of the chest, however, as indicated by the quantity of air which we can expel, is in strict relation to the minute difference of a single inch of stature, or to 10 lbs. of weight. It appears probable that the function of an organ may be exactly relative to the size of the body, increasing or decreasing with it, while the organ itself bears no visible relation of volume either to its own activity or to the dimensions of the body.\nThe greatest perpendicular depth of the thoracic cavity, nearly corresponds with the greatest lateral measurement ; or if the depth be 8\u20197 the breadth is 9*7, and allowing for the mobility of the base of the thorax, the depth may yet more closely correspond to the breadth. The average perpendicular depth of the female thorax exactly corresponds with the average\nbreadth, being 8*1 inches in both measurements. The greatest antero-posterior diameter in both sexes, i. e. from the sternum to the deepest part of the great lateral groove at the angle of the rib, is always less than the greatest lateral breadth, being as 6 to 9 in the male, and as 6 to 8 in the female.\nThese diameters, however, in no way correspond to the stature. A man, 5 feet 4 inches high, measured from the apex of the chest to the base 10\u00a3 inches, whilst a man of 5 feet 10 inches, only measured inches in the same direction, or the shorter man exceeded the taller by 3 inches in the perpendicular depth of his thoracic cavity: \u2014 but the taller man could exceed the shorter by a volume of 77 cubic inches of air at one deep expiration. In fact, the whole of the\nFig. 669.\nSections of the Chest at the base.\nTable F. \u2014 Average Measurements of the Thorax.\n(The mean of the measurements of fourteen males and six females, \u2014 given in detail in Med. Chirurg. Trans. 1846. Vol. 29. p. 176.)\n\t\t\tMALES.\tFEMALES.\nAge\t-\t-\t-\t51 years\t40 years\nHeight ------\t-\t-\t66 in.\t62 in.\nWeight (without clothes)\t-\t-\t-\t110 lbs.\t94 lbs.\nWeight of heart -\t-\t-\t13 oz.\t11 oz.\nWeight of right lung\t-\t-\t-\t30 \u201e\t19 \u201e\nWeight of left lung -\t-\t-\t25 \u201e\t17 \u201e\nExternal circumference over nipples\t-\t-\t32 in.\tSO in.\nInternal circumference (maximum)\t-\t-\t32 \u201e\t24 \u201e\nInternal circumference of right half\t-\t-\t15 \u201e\t13 \u201e\nInternal circumference of left half\t-\t-\t15 \u201e\t13 \u201e\nGreatest depth, from before backwards, of thorax -\t-\t-\t6\u20195 \u201e\t6 \u201e\nDistance between sternum and bodies of dorsal vertebra?\t-\t-\t4 \u201e\t4 \u201e\nProjection of dorsal vertebrae into thoracic cavity -\t-\t-\t2'5 \u201e\t2*5 \u201e\nGreatest breadth of cavity of thorax\t-\t-\t9 \u00bb\t8 \u201e\nInternal superficies of costal walls of thorax\t-\t-\t258 sq. in.\t212 sq. in.\nSuperficies of diaphragm -\t-\t--\t49\t,,\t35 \u201e\nSuperficies of entire boundaries (diaphragm and costal\u2014)\t-\t-\t307\t\u201e\t247\t\u201e\nVolume of right half of thorax -\t-\t-\t151 cub. in.\t109 cub. in.\nVolume of left half of thorax\t-\t-\t-\t182 \u201e\t141\t\u201e\nVolume of entire cavity -\t-\t-\t333\t\u201e\t250\t\u201e\nDepth of right lung from apex to arch of diaphragm\t-\t-\t7 in.\t7 in.\nDepth of left lung from apex to arch of diaphragm\t-\t-\t9 \u201e\t8 \u201e\nDepth from between apices to diaphragm\t-\t-\t8 \u201e\t7 \u201e\nDepth from before backwards \u2014 right lung (maximum)\t-\t-\t6 \u201e\t5-5 \u201e\nDepth from before backwards \u2014 left lung (maximum)\t-\t-\t6-5 \u201e\t5\u20185 \u201e\nDistance between centre of apices of lung\t-\t-\t2-5 \u201e\t2-3 \u201e _\nVital capacity\t-----\t-\t-\t205 cub. in.\t187 cub. in.\nIn the males the left apex was highest in 6, the right in 6, and in 2 the summits of the apices were on the same level ; in the females, the left apex was highest in 2, and the right in 4.\n3 x\nVOL. IV.","page":1041},{"file":"p1042.txt","language":"en","ocr_en":"1042\nTHORAX.\ninternai measurements (cubic or diameter) clearly bear no relation to the height or weight of the man, whilst vital capacity * does so in an exact ratio.\nIf we take a cast of the thoracic cavity and view the base, it presents the shape of the figures in diagram fig. 669. which gives a mean measurement, in the males of forty-six, and in females of thirty-five, superficial inches In the diagram (reduced by scale), we affix the height of each case, and the area in superficial inches of such section.\nBut the base of the thorax presents another measurement, that of the absolute area of the diaphragm. By the figs. 2. and 3., art. Diaphragm, this muscle will be noticed as a large muscle of a vaulted form. C.fig. 670. repre-ents a section of a thorax, the measurement of\nFig. 670.\nDimensions of the diaphragm in three stages.\nC, ordinary stage. B, spread out A, completely extended. D, relative difference between expiration and inspiration.\nwhich is forty superficial inches; the figure B, next above, is the diaphragm of the same person spread out, which is extended to 110 square inches, being nearly three times the area of the former figure ; even in this condition the centre is quite free, and not upon the stretch, though the circumference is so. The full measurement is nearly obtained, by slitting up the sides, as shown in figure A. and this condition gives it an increase of twenty-two superficial inches, making altogether 133 square inches ; but even in this condition the entire arched muscle is not perfectly spread out. This was the diaphragm of a man five feet six inches high, with an exceedingly\n* By \u201c vital capacity \u201d is meant the measure of the mobility of the chest, as more fully explained hereafter. (P. 1056.)\nsmall chest, only twenty-nine inches in external circumference, and whose vital capacity was 188 cubic inches. The section, therefore, of the thorax to the area of the diaphragm is as 40 to 133, or 1 to 3*3. This renders the base of the thorax highly mobile.\nThere is, perhaps invariably, a difference in the dimensions of the two sides of the thorax, in favour of the left side. The least difference which we observed was one cubic inch, but we think there must have been some error in this observation. Passing this over, we may say that the difference between the two sides varies from 10 to 77 cubic inches, and that, in all cases examined by us, the left side was larger than the right. This difference, also, we have found not to bear any relation to sex or stature. One female of 5 feet 4 inches in height had a difference of 77 cubic inches, which exceeds by 10 inches any of the males which we examined, up to 5 feet 10 inches high.\nOf the Respiratory Muscles. \u2014 There are certain muscles especially destined to expand and contract the thoracic cavity, and there are others which act in different degrees as accessories, they may be classed as direct and indirect respiratory muscles.\nThe direct respiratory muscles are, intercostales externi and interni, levatores costarum, infra costales, triangularis stcrni, and the diaphragm. The indirect respiratory muscles are all those which straighten the spine or aid in fixing the whole body for the thoracic muscles to act from as a fixed point, whilst by their other attachment they elevate or depress the ribs ; these are particularly the muscles of the neck and upper extremities, and those composing the walls of the abdomen. More indirectly still, the muscles of the limbs assist in respiration; \u2014 in difficult respiration, the patient seizes hold of any fixed object, whilst he employs his whole muscular force to assist in inspiration, or, as Boerhaave has expressed it, \u201c scarcely any particle remains in the body which is not more or less concerned in the business of respiration.\u201d* The indirect respiratory muscles, in fact, comprise nearly all the muscles of the body; therefore we shall only notice the direct respiratory muscles. The diaphragm has already been described (art. Diaphragm).\n1. The intercostal muscles are arranged as two thin laminae between the ribs ; one lamella is external to the other, hence they are named external and internal. The fibres of each layer are oblique in their direction in reference to the ribs, and each layer has its fibres disposed in a contrary direction to those of the other ; thus they are said to decussate. The twelve ribs form eleven intercostal spaces, consequently there are eleven such decussating lamellae on each side of the thorax, and twenty-two in all. Their attachments are to the inferior border of one rib, and to the superior\n* Pr\u00e6lect. ad Instit. 601. Morgagni. By Alexander, vol. i. p. 357.","page":1042},{"file":"p1043.txt","language":"en","ocr_en":"THORAX.\n1043\nborder of the next below. They do not accompany each other throughout the entire intercostal space. These muscles, therefore, differ from each other in two ways, in the direction of their fibres, and in the extent of their attachment, for neither set are prolonged throughout the entire length of an intercostal space.\n(a) Intercostales externi.\u2014These have their fibres running obliquely downwards and forwards ; they are continued throughout the whole osseous intercostal space, i. e. from the tubercles of the ribs, to where the cartilages commence ; here they terminate. Haller once noticed these fibres \u201c continued without interruption to the sternum, filling up the in-tercartilaginous spaces.\u201d* A thin aponeurosis is prolonged from the free anterior margin of this layer, up to the sternum, This muscular layer is thicker than the internal layer. Fig. 671. represents the anterior extremity of this\nFig. 671.\nExternal intercostals. \u2014 Anterior view.\nlayer, where it terminates with the osseous part of the rib, and Jig. 672. the posterior view, commencing at the vertebrae.\n(b) Intercostales mterni.\u2014 These, as their name implies, are internal to the above layer. Their fibres are likewise oblique, and have a contrary direction, downwards and backivards crossing the former layer. They commence at the sternum, fill up the intercartilaginous spaces, and part of the interosseous spaces, and terminate at the angles of the ribs. Fig. 671. represents them commencing at the sternum, and disappearing behind the external layer. Figs. 673,and 674.show them for the remainder of their course ; in fig. 673. they will be seen to terminate short of the vertebral column. A thin aponeurosis is prolonged from their free margin backwards, to the end of the intercostal spaces.\nAll the intercostal fibres are oblique in their direction, with reference to the spine and sternum. The fibres of one intercostal space differ\n* El.-Phys. tom., iii. p. 29.\nFig. 672.\nExternal intercostals. \u2014 Posterior view.\nin their degree of obliquity relatively to those of other intercostal spaces Thus, broadly, it may\nFig. 673.\nInternal intercostals. \u2014 Posterior view.\nbe stated that the external intercostal fibres increase in the degree of their obliquity as they\nFig. 674.\nInternal intercostals. \u2014 Anterior view.\nproceed from the first to the last intercostal space and that the internal intercostal fibres,\n3x2","page":1043},{"file":"p1044.txt","language":"en","ocr_en":"low\nTHORAX.\non the contrary, decrease in the degree of their obliquity as they proceed in the same direction. Moreover, for the most part the external fibres increase in their obliquity in the same intercostal space as you proceed from the vertebrae towards the sternum, and the internal intercostal fibres, on the contrary, increase their obliquity from the sternum towards the vertebrae, therefore they seldom decussate at right angles to each other, or form a perfect cross like the letter X. This is their general relative position at death, but, during life, in every stage of respiration, their degree of obliquity varies. The obliquity of the intercostal fibres should be viewed more with reference to the spine than to the ribs, because we shall show that their action is relative to the spine, and not to the ribs and that they may be perpendicular to two ribs, while they are oblique to the spine, because the ribs are themselves oblique. We have never seen any of the external intercostal fibres perpendicular to a rib, but we may see that arrangement in the internal layer of the lower intercostal spaces (fig. 673.). The omission of the relative position of the spine with reference to the obliquity of these muscles has led to many false conclusions as to their action in respiration. Let e e (Jig. 675.) represent a spine or a rigid\nFig. 675.\ndicular to the two bars ; now move the bars up to p 3, also at an angle of 45 \u00b0 with e e, and the fibre l k becomes more oblique than at the position p 2. Therefore a tension may change from the oblique to the perpen-dicular relatively to the ribs ; but it can never so change its relation to the spine. Thus l\" k\" and i/ k' between the bars at p 3 cross each other, in the same direction, but in different degrees of obliquity; when the bars are at p 4., they decussate in directions contrary with reference to the bars, but not with reference to the body E E. The position of the ribs is similar to the bars at p 4, therefore the decussation of the intercostal muscles must be viewed wLh reference to the spine. The intercostal fibres never cross each other like the lines l'k' and i/'k\" (fig. 675.), nor can they, by any change of movement, ever assume thatposition ; i. e. if they do not decussate in a direction contrary with relation to the spine, in no change of position, throughout the range of a semicircle, can they ever become directly decussating fibres but when they directly cross each other as v d and v'b (fig. 676.) relative to e e, in every other position to which the bars\nFig. 676.\n&\nbody, and a c, b d two levers representing can be moved, they will be seen still to main-ribs, allowing of free rotation at their centres of tain the same decussation, motion a and b. These two bars are per- Action of the intercostal muscles. \u2014 There pendicular, or at 90\u00b0, with reference to the is, probably, no subject in the whole range of body EE; let l k represent a connecting science which has excited more violent con-tension or elastic fibre of any kind, this is tention and acrimonious dispute, than that oblique with reference to the two bars Ac of the action of the intercostal muscles. The and b d, but move these bars down to the illustrious and learned Haller could not enter position of p 4, at an angle of 45\u00b0 to the this field of inquiry without pausing to ob-body e e, and the fibre l k becomes perpen- serve : \u201c Let it be allowed me to deplore-","page":1044},{"file":"p1045.txt","language":"en","ocr_en":"THORAX.\n1045\namong the miseries of human life, that such anger and bitter quarrels should be forced upon us on account of matters wherein we are so little personally concerned.\u201d* * * \u00a7\nYet, strange to say, Haller opposed with extreme violence his contemporary Hamber-ger, whose investigations on this subject, though still extant, fell, consequently, into oblivion.\nWe know not who discovered the two sets of intercostals. There appears to be no account of them prior to Galen, a. d. 131. He observes, \u201cthe intercostal muscles help the midrilf, that they might draw the chest in-ward.\u201df Albinus (a.d. 1770) considered that both the internal and external layers \u201c raise the ribs.\u201d J H. Cooke, a learned compiler of 1651, believed, they \u201c constrained and dilated the chest,\u201d \u2014 \u201c that the external layers bear down the ribs, and that the internal separate the ribs, so enlarging the thoracic cavity.\u201d \u00ff Strange to say, after this Cooke divests these muscles of all thoracic motion whatever.\nIn 1685 it was the received opinion that the external layer dilated, and that the internal layer contracted the thorax || John Al-phonso Borelli led the way to a different opinion, which prevailed amongst most physiological writers. He believed, from mathematical reasoning, that \u201c the fibres crossing each other produced only one effect, viz., the drawing of the ribs together,\u201d \u2014 acting in the diagonal of the decussation. It is curious that he never considered the probability of the two forces acting separately, as other antagonising muscles can do. W. Cheselden believed that both these muscles dilated the thorax, acting as elevators of the ribs, when the 1st rib was fixed by the scaleni and serratus posticus posterior. ** * * \u00a7\u00a7\nCooke follows the views of Cheselden and Borelli.ff Benjamin Hoadly takes another view ; and, in so doing, illustrates the subject with diagrams, and comes to the conclusion that the external layers elevate, and that the internal depress the ribs ; and that their combined action is to arrest the respiratory movement at will. He also says, \u201c neither range can by their action push the ribs asunder.\u201d Winslow agrees with Borelli : presupposing, as usual, that the first rib is fixed. \u00a7\u00a7\nStill the subject continued to be warmly disputed, when Haller published a controversial paper in 1746. In his \u201c Elements,\u201dhe treats the\n* El. Phys. vol. iii. p. 36.\nf De Usu Resp., ch. 15., 5 lib., De Usu Partium,\nj Tr., fol., ed. 1777. Tab. xvii. 9, 10, et seq.\n\u00a7 Cooke\u2019s Descrip. Anat., fol., 1651., p. 257.\n|i Samuel Collins\u2019s System of Anat., fol., 1685, vol. ii. p. 825.\nDe Motu Animalium, pars secunda. Lugduni Batavorum, 1710, p. 106., Prop. 84., Tab. xviii. Pig. 2.\n** Anatomy of the Humane Body, 3rd ed. 8vo., Lond. 1726, p. 117.\nff Cook\u2019s Anat. and Mechanical Essays, Lond. 1730, vol. i. p. 282. et seq. f J Gulstonian Lect. on Resp. 4to., Lond. 1740,\np. 6.\n\u00a7\u00a7 Anatomical Exposition, 4to,. Lond. 1749, vol. i. p. 318.\nsubject at length, siding with those whom he thinks are right, and confirming the same by many direct experiments.* Haller\u2019s view is, that the external layers elevate the ribs, because their superior attachment is nearer the vertebrae than their inferior one. Francisais Boissier de Sauvages agrees with him ; and the same is held by the majority, yet some doubt it.\nHis opinion touching the internal layer is, that they likewise act as associates and elevators of the ribs with the external layer, because \u201c their superior attachment is nearer the sternum, and further from that bone in the lower ones;\u201d likewise, that \u201cthat portion of the internal layer placed between the bony parts of the ribs, cannot have a different action from that portion placed between the cartilages.\u201d Joh. Swammerdam, Francis Bayle, J. Wilhelmus Pauli, Christianus Vater, Francis Nicholls, J. Fredericus Schreiber, differ from this, believing that the internal layers draw down the ribs.\nNow follows a sharp antagonist to Haller, viz. Hamberger, whose disputes with Haller we gather from Haller\u2019s writings, and not from Hamberger\u2019s writings.\nHamberger breaks out with an entirely new view, which excites Haller to controversy.!\nHamberger, says Haller J, believes that the external intercostal muscles have one action, \u2014 that they would raise the sternum : \u201c that the internal layer would depress it.\u201d Hamberger makes a machine \u201c to demonstrate, that when the ribs are raised by these muscles their intervals are dilated ; when depressed, on the contrary, they are diminished.\u201d He furthermore gives, as his own discovery, that \u201c the internal intercostals conjoining the osseous portions of the ribs, and that portion which is between the cartilages, will raise them, and are therefore associated in action with the external layer.\u201d Hamberger was the first to assign a double action to the same class of muscles : he likewise believed that the whole ribs were lifted simultaneously^ Haller disputes the validity of Hamberger\u2019s experiments, upon the ground of his not considering the relative mobility of the first and second rib ; because, says Haller, if the depressing power of the intercostal muscles is to the first rib as 20, the elevating power on the second rib, by reason of the difference of length and mobility, is as 380, nearly nineteen times greater ; and the lower rib is to each superior rib, as far as the seventh, more moveable, in the ratio of 109 to 79. |j We cannot see, with Haller, how the ten-\n* Vide Elementa Physiol. Corporis Humani, tom. iii., p. 28., et seq. Lausan. 4to., 1766..\nf Hamberger was bom 1697, and died in 1755. Haller\u2019s first anatomical paper upon respiration appeared in 1746, and his Elementa Physiol. Corporis Humani, in 1757-66.\n% El. Phys. ib. p. 37.\n\u00a7 Hamberger\u2019s writings on this subject were an essay De Respirationis Mechanismo, Jen\u00e6, 1727, and also Physiologia Medica, Jen\u00e6, 1751. \u2014 Ed.\nII Loc. cit. p. 39. et seq.\n3x3","page":1045},{"file":"p1046.txt","language":"en","ocr_en":"1046\nTHORAX.\ndency of action of a muscle can be affected by the degree of mobility of a joint ; for it is not necessary to the direction of the action of a muscle that a bone should move. Haller also denies that the two crossing fibres lengthen and shorten inversely to each other ; or that the intercostal spaces widen by their action. Haller performed many experiments ; he applied strings to the ribs of a wet preparation, representing the muscles, and pulled the strings, and the intercostal spaces diminished. By vivisections he determined, that in inspiration the internal intercostals, \u201c simultaneously with the external layer, contract, swell, and wrinkle, become perpendicular and hard, with united lifting of the ribs in rotation, the turning of the lower border forwards, the protrusion of the sternum, the descent of the diaphragm,\u201d &c. On the other hand, he observed in \u201c expiration, relaxation of the whole series of intercostal muscles, increased length and obliquity, increased distance between the spaces, relaxation of the diaphragm, repression of the sternum, the descent of the ribs, narrowing of the chest,\u201d &c.*\nIt is curious to see that he makes the cubic space of the thorax diminish with the intercostal spaces widening. Nor do we wonder at his observing, in his vivisections, a contraction of both sets of these muscles, for he not only skinned his animals, but \u201c cut down and destroyed the external layers of intercostals, to lay bare the internal layer.\u2019 \u201cBesides lap-plied (says Haller) pain and fear, being more efficient than mere pain itself,\u201d by puncturing the diaphragm to cause dyspnoea! Under such circumstances \u2014 an animal tied down, divested of all superficial muscles, with a pierced chest, \u2014 in \u201c pain and fear,\u201d \u2014 and writhing under the scalpel,\u2014producing tetanic convulsions, and then a death-like relaxation from syncope, \u2014 surely in such a condition the action of the respiratory muscles, so sensitive to the least mental emotion, could not well be determined.\nAlthough Haller appears positive, yet he concludes his controversy with a brilliant question,\u2014a vivid picture of his master mind, \u2014 \u201c Why has nature made two, rather than one set of intercostal muscles, if, indeed, the function of each is the same?\u201d-)' Haller\u2019s views have, however, prevailed to this day, and are still taught in our schools. _ Some authors have assigned but little to these muscles, counting them as mere associate muscles ; others, that they are \u201c wholly and solely \u201d to form the thoracic parietes ; others that they are rather movers of the spine.\nDr. John Barclay, a standing authority, observes, that the supposition of the two sets being antagonists in their actionr \u201c is now obsolete,\u201d and must \u201c have been formed by the very witchcraft of imagination, in defiance of all observation and experiment.\u201d X\nLastly, Dr. Sibson has made a commu-\n* El. Phys. ib. p. 43.\nt lb. p. 44.\nj Barclay \u201c On Muscular Motion,\u201d 8vo. Ed. 1808, pp. 533, 534.\nnication upon this subject. He observes, that \u201c the scaleni invariably act during the whole time of inspiration ;\u201d and that the function of the intercostal muscles is complicated ; thus, \u201c the external intercostals, between the thoracic set of ribs, are throughout inspiratory ; those portions between their cartilages are expiratory, between the diaphragmatic set of ribs they are inspiratory behind, expiratory to the side and in front, and between their cartilages they are inspiratory ; between the intermediate set of ribs they are for the most part slightly inspiratory between the ribs, and expiratory in front between the cartilages.\u201d\n\u201c The internal intercostals of the thoracic ribs are expiratory behind and inspiratory in front, if the ribs approach there, and are inspiratory between the costal cartilages. Between the diaphragmatic and intermediate set of ribs, and between the cartilages, they are thought expiratory.\u201d* From this view of Dr. Sibson\u2019s, we venture to gather, that different fibres of the same layer of intercostal muscle have diametrically opposite actions. We do not understand upon what ground it can be demonstrated that one muscle having a given action between two ribs, shall, between the same ribs, and observing the same obliquity and same attachments, present a directly contrary action ; the conditions are the same, and therefore the action must be the same. These views, however, of Dr. Sibson, in the paper in question, are not borne out by the narration of any experimental facts. Insufflation on the dead body is not the movement of inspiration in the living subject. It is better to assign to these muscles the terms of elevators or depressors of the ribs, instead of inspiratory and expiratory muscles.\nAll these observers, as far as we have seen, pre-suppose that the 1st rib is fixed by the scaleni (this is the view now taught) ; and that according to the fixing of the 1st rib, all the intercostal muscles are either elevators or depressors of the ribs. It is curious to contemplate that, out of elements so few, two ribs and two muscles, opinions so contrary should be held with regard to the action of these muscles. They have nevertheless an action as definite as any other muscle in the body.\nWe may here observe, that, although the chest is conical, the libs segments of circles, and the spine mobile, yet treating them as planes and lines will not lead to error. Two parallel bars, rotating on a centre, will increase and decrease the perpendicular distance between them ; so they will, if curved like the ribs. This we have determined by experiment.\nAlthough the rib has two movements, elevation and rotation, yet these are associates, and do not obstruct each other. We shall employ the same diagrams as used by Dr. Barclay, when describing the same muscles.\nThe intercostal muscles act as a force between two moveable ribs or levers ; therefore let us consider \u2014\nTV. Phil., Pt. 4, 1846, pp. 543, 544.","page":1046},{"file":"p1047.txt","language":"en","ocr_en":"THORAX.\n1047\n1st. The movement of such levers, when rotating.\n2nd. The effect of forces, oblique, perpendicular, and decussating, upon such levers.\n1st. The movement of the levers. \u2014 Let fig. 677. a represent a series of parallel bars,\nFig. 677.\nR\tA\nallowing of free rotation upon a rigid perpendicular body a a ; let the free extremities of these bars be kept apart, so that the bars may at all times be parallel to each other. In this condition a certain distance exists between the bars, and a certain distance between their free extremities and the perpendicular body a a. Let b represent the same bars moved into another position, resembling that of the ribs ; in this position, the two conditions seen at a are altered. The perpendicular distances between the bars are diminished, and the distance between the free extremities of the bars and the body b b is likewise diminished. If the direction of this motion were still continued, the bars would ultimately touch each other, and their free extremities would be still nearer to the body b b. But let the bars be elevated, as in c c, and the same condition obtains as in the bars at b b, viz., they approximate each other, and the free ends come nearer to the body, c c. In this case the bat's only have moved ; but the same effect can be obtained without moving the bars. Let a b {fig. 678.) be two bars at their maximum distance, while horizontal; at a b, and a' b', they have nearly attained their minimum perpendicular distances, though still horizontal, because the rigid bodies c c and c' c' have been moved respectively. Now, if we join these hree last figures into one, as in fig. 67 9., an then move the bars simultaneously, some bars will approximate each other, whilst others will recede. The superior four are at their maximum perpendicular distance from each other ; while the 4th, 5th, and 6fh are at a medium perpendicular distance, and the 6th, 7th, and 8th bars at their minimum distance.\nThe distances of these bars are regulated by the position of the rigid body representing the spine. If all of them were moved upwards\nFig. 678.\ne - ------------\nDiagram representing the position of the ribs affected by the position of the spine.\nsimultaneously, the first four would approximate, whilst all the rest would recede from each other. Therefore the positions of the different parts representing the spine in fig. 679. command and regulate these changes.\nFig. 679.\nDiagram as in fig. 678. with the three portions conjoinedm\nFrom this we learn, that the bars cannot rotate without changing their distances, and that when they are at 90\u00b0 with reference to the body a a {fig. 677.), they are at their maximum distance from each other, and as they pass this position on either side, this distance diminishes.\nIn the human body the spine may represent the body to which the bars are attached {fig. 677.). The movement of the ribs will obey the same law in receding or approaching each other, and whether they increase or diminish their intercostal spaces, will depend upon the relation they bear to the spine.\nFig. 682. is a cast, from a dissection of the thorax of a male subject, weight 1071bs., height 5ft. 4in. This correctly represents the natural position of the ribs, when the thorax is in a state of complete expiration, or with only the residual air in the lungs. The position of the\n3x4","page":1047},{"file":"p1048.txt","language":"en","ocr_en":"1048\tTHORAX.\nribs is very oblique ; the spine is curved ; therefore the relation of the ribs to the spine is different according to the curve, as are the bars to the body representing the spine {fig. 679.). It will be seen that the inferior six or seven ribs are at a more oblique angle to the spine than the superior ribs. The spine does not curve sufficiently to bring the upper ribs to an angle of 90\u00b0 with the spine; therefore, if all the ribs were raised simultaneously, they would all increase the breadth of their intercostal spaces, whilst their sternal end would recede from the vertebrae, and thus, by their elevation, the thoracic cavity would be enlarged, until they attained the angle of 90 0 to the spine. But if the elevation were carried beyond this point, the intercostal spaces would diminish, and thus the thoracic cavity would decrease. Fig. 684. is a posterior view showing the sloping position of the ribs more clearly. Now, if the spine were perfectly erect, the ribs would have a greater range, and consequently the upper ribs could be elevated higher, and thus still more increase the thoracic cavity. A man\nFig. 680.\nThorax as at death.\ncan expire a greater volume of air when perfectly erect, than in any other position. On the other hand, if we curve the spine, we limit the divergence of the ribs, because then we bring the ribs more into the position of a b and a' b' ( fig. 678.). Thus, in diseases of the spine, when angular curvature is extensive, the ribs are materially limited in their capability of increasing the perpendicular depth of their intercostal spaces, and consequently the perpendicular depth of the thorax.\nFig. 666. is an instance of angular spine, reducing the ribs to their minimum distances without their moving. We have found by experiment, that the greatest volume of air which persons with angular spine can expire, is little more than equal to the volume of air of an ordinary respiration ; i. e. from 20 to 40 cubic inches, instead of 180 to 200 cubic inches.\nThe following experiment proves that the\nribs are all elevated when the chest is inflated, and that the spine is straightened. Into the thorax (fig. 680. et seq.) we insufflated, or forced into the lungs 310 cubic inches of air, and a second cast was taken. The changed position of the ribs and spine is represented in figs. 681. 683. and 685. where it will be seen that all the ribs are raised ; their perpendicular distances or intercostal spaces are all increased, and the spine is more erect.\nThis experiment, therefore, demonstrates two things : 1st, that by artificially inflating the chest, the intercostal spaces are widened, and 2dly, that the spine becomes more erect. It is an experiment most unfavourable for showing these two points, because the altered shape of the thorax by insufflation is not to be compared with the exceedingly enlarged condition produced by vital inspiration ; in which case the spine becomes more erect, and the intercostal spaces consequently wider. By placing the fingers in the intercostal spaces of a living subject during deep inspiration and expiration, it may easily be perceived that in the former they widen,\nFig. 681.\nThorax artificially inflated with air.\nand in the latter they collapse. From 3000 observations we have found that, in deep inspiration, the body becomes more erect, and less so in expiration.\nInsufflation is not the same, in effect, as inspiration. In the former we force air into the chest, until the parts most yielding, as the diaphragm and abdominal parietes, are rendered so tense that their tension is sufficient to overcome the elastic force of the ribs, their cartilages, and the lungs ; then, and not until then, do we move the costal part of the thorax. On the other hand, in the living and deep inspiration, we lift the ribs and sternum, the most unyielding portions, first. These solely produce the threatened vacuum which inflates the lungs, whilst very little, if any, is accomplished by the diaphragm.\nThe following table shows the measurements of the thorax, when expanded by inspiration and insufflation.","page":1048},{"file":"p1049.txt","language":"en","ocr_en":"THORAX.\n1049\nFig. 682.\tFig 683.\nThorax as at death.\tThorax artificially inflated with air.\nTable G.\u2014Table of the Dimensions of the Thorax and Abdomen, in the Dead and Living Subject, with the same Quantity of Air distending them.\n\tThorax.\t\t\tAbdomen.\t\t\nConditions at the time of observation.\tCircum over nipples.\tDiam. lateral.\tDiam. ant..post.\tCircum.\tDiam. lateral.\tDiam. ant.-post.\n\tin.\tin.\tin.\tin.\tin.\tin.\nDead\u2014Natural collapse\t29f\t10\t8\t29*\t8*\t4\nInsufflated\t31*\t10*\tSl-\t31*\t10\tn\nAlive\u2014Expiration\t32\t1H\tot\t25\t10*\tn\nInspiration\t37\t12*\tHf\t25*\t11\t8*\nDifference\u2014\t\t\t\t\t\t\nBy insufflation, dead\t1*\t1 2\t3 *\tIf\tH\tit\nBy inspiration, alive\t5\t1\t2f\t*\t3 *\ti","page":1049},{"file":"p1050.txt","language":"en","ocr_en":"1050\nTHORAX.\nThese facts show that we should be guarded in determining the living respiratory movements by experiments upon the dead subject.\nIt should be constantly borne in mind, that to increase or diminish an intercostal space is to elevate or depress the ribs, and that to elevate or depress the ribs is to increase or diminish their intercostal spaces : the one cannot be accomplished without the other. Some authors have spoken of these as distinct ; thus, that in inspiration the superior ribs approximate each other, whilst they are raised, or that their rising or falling does not necessarily involve an increase or diminishing of the intercostal spaces ; but these two changes are simultaneous and cannot be done separately.\n2nd. The effect of tensions, oblique, perpendicular, and decussating, between the moveable levers or ribs.\u2014We employ a strip of vulcanised Indian-rubber for a force representing muscular contraction. A strip of this substance, of uniform thickness, \u00a3 of an inch broad and 10 inches long, increased its length, with an increasing weight, as follows : \u2014\nWeight\nIncreased length of Indian\n1\t+ the pan holding the\tgr. rUin\u00e7hes. weight = 850gr. =\t1287a\t|\t\n2\tdo.\t= 1725\tt\n4\tdo.\t= 2600\t1\n8\tdo.\t= 4350\tIf\n16\tdo.\t= 7850\t4\n32\tdo.\t= 14850\t12i\n64\tdo.\t= 28850\t28\u00a3\nFig. 686.\nEffect of oblique tension on separate bars.\ndemonstrated by a model, using a spring or Indian-rubber as the tension, and may be\nAlthough not exactly in accordance with the law of perfect elasticity, yet it is roughly so and enough for our purpose, viz. the tension is greatest when most stretched, and weakest when least stretched, corresponding with muscular contraction.\nLet e e (fig. 686.) be fixed, a b and c u two moveable bars as before, t an oblique tension ; if t shortens, it has been supposed that the two bars would assume the position of A b' and c d ; but not so : they both rise like A b\" and c d\" until the two bars touch each other.* If we prevent this touching of the two bars by a rigid link, like that on parallel rulers, placed as at s fig. 687., then the tension will still raise the bars to o o'. In this experiment three circumstances may be noticed. 1st, that the bars have been elevated ; 2dly, that the perpendicular distance between them has been diminished ; and 3dly, that the tension t has been shortened in attaining the position o o'. Place the tension in a contrary direction, as between the bars a' b' and c'd', and the bars are brought into a contrary position, \u2014 drawn downwards to o' o'\". This can be\n* This appears to have been known to Hamberger ; but the author of this article was not aware of it until four years after he first introduced this movement to notice. (See Med. Chirurg. Trans, vol. 29, p. 213.) It is certain that Hamberger\u2019s views were not taught in any physiological school in this country, Germany, or France, nor noticed in any of our philosophical works.\nFig. 687.\nexplained as follows. Let a b, fig. 688., represent one bar, c D the perpendicular fixed body ; b is the free extremity of the bar ; k an axis from which a parallel bar has been removed. Let e, i, and o be other fixed points ; connect e to b by an elastic tension, and the bar b will be moved towards e. Let the tension be fixed at i or o, still the bar b will be raised towards the respective points. Let the tension be fixed at k (the centre of motion of the bar which we suppose is removed), and still the bar a b will be raised upwards towards K, and assume the position of a b, k l (fig. 689.) at M. But it is not necessary to this that the elastic force should extend from","page":1050},{"file":"p1051.txt","language":"en","ocr_en":"THORAX.\nFig. 690.\nlOM\nFig. 688.\nK to L in order to produce this motion : half of it might be wood, bone, or iron, provided the other half retained its elastic power. The effect would be the same, and the bar ab at IV would be elevated by the tension between t l,\nFig. 689.\n\t\t\n\tc-\t\u2014 J\n\t\tB\u2019 l\n(\u2022\t<\u00a3\t\t<=\t | D\n\t\t\notherwise the free bar would approximate the fixed bar c d. Therefore, one fulcrum is pushed upon by one bar, and pulled upon by the other. If the bars were kept fixed, and the body representing the spine was left free, the tension would draw this last mentioned body into the\nFig. 691.\nconnecting the fixed point k with l by the rigid body k t. It is the omission of the fulcrum k, in calculating such oblique forces, which has hitherto obscured the explanation of the intercostal muscles.\nThis may be illustrated in another way {fig. 690.). Let ab and cd represent bars as before upon a c ; t' the tension ; let c d and a c be fixed ; withdraw the pin at a, and the bar A B is drawn forwards into the position B'', and the tension t becomes perpendicular to the two bars. On the other hand, reverse the experiment, as in fig. 691.; supposing c D and the perpendicular body c A fixed, withdraw the pin at A, and the bar a b is drawn backwards to b'. This presupposes the bars kept apart,\nposition of c c and c' c'fig. 678. Therefore, the element of the two fulcra is the chief agent for directing their upward or downward movement, under an oblique tension. If we arrange two bars with one fulcrum {fig. 692.), and allow\nFig. 692.\nthe tension to act as before, then the effect is only to draw the two bars together, as o b and o' d {fig. 693.). If we have an arrangement to substitute two fulcra at a a' fig. 692. and withdraw the centre fulcrum, then the two bars rise as before.\nFig. 693.\nnn\nNow we shall suppose the bars at an angle of 90\u00b0 to the body representing the spine.\nA perpendicular tension (l o,fig. 694.) admits, of course, of no variation ; oblique tensions admit of two variations :","page":1051},{"file":"p1052.txt","language":"en","ocr_en":"1052\tTHORAX.\na, obliquity in contrary directions. by degrees of obliquity in each direction.\nFig. 694.\nT D\nThe perpendicular tension (l o, Jig. 694.) produces but one effect, that of approximating the two bars a c and b d, because the force of l o is acting upon a l and b o, levers of the same length, their movements being the same they would meet in the middle distance at s. But if the bars are kept parallel by a rigid link like s, fig. 687. the perpendicular tension would produce no apparent effect upon the two bars. They might be rotated in any direction, and the tension would remain of the same length ; for example,in fig.695. let t 2 be the perpendicular tension between the bars a b c d, move the bars to s or s', and the ten-\nFig. 695.\nDiagram showing that perpendicular fibres neve? alter their length.\nsion is the same length, k k k, &c., may represent different places in the rotation, at each of which the tension t or k is the same length, although the bars at s, t 2, and s' are at different perpendicular distances from each other. A rigid connective, as wood or wire, may be substituted for the tension, an-this will equally allow of the bars being rod tated, and consequently changing their perpendicular distances to each other. Hence it will be seen, that each of the lines k k k, are of the same length, although the two semicircular lines describing the revolution of the bars are constantly changing in their relative distance to each othe We then seer, the possibility of having a rigid body connecting two bars, which shall nevertheless recede and approximate each other. From this we may gather, that though the sternum is rigid, and the cartilages, perhaps, ossified, the ribs may nevertheless maintain the capability of altering the breadth of their intercostal spaces.\nPerpendicular tension, therefore, like l o, (parallel to a b,) cannot rotate the bars, because they never change their length.\nAll tensions are oblique which have one of their attachments nearer to the spine than the other, therefore, in fig. 694., l k and L t are oblique tensions. An oblique tension, hence, is acting on bars at dissimilar distances from their fulcra ; thus in fig. 696.,\nFig. 696.\ntension t' is oblique to the line a a, and the points on the lines a b, ad, to which the tension f is attached, is represented by the lines a m and A m. And the law of action of such tension is, that it tends to move both bars or ribs towards that fulcrum which is nearest to one of its attachments. Therefore tension l k (fig. 694.) would rotate the bars towards b, and tension l t towards A. The force of a given oblique tension between such bars is modified by two circumstances, \u2014 by the degree of obliquity, and by the obliquity of the bars in reference to the body which represents the spine.\nOf the degree of obliquity of a tension. \u2014 Let fig. 697. a b, c D, represent bars as before, the different connecting lines tensions of different degrees of obliquity, but of the same power of tension. L k is perpendicular, and has no rotating power, l k1 possesses a certain amount of power, l k2 more power, and l a the maximum power, or the power of rotating","page":1052},{"file":"p1053.txt","language":"en","ocr_en":"THORAX.\nFig. 697.\nthe bars increases with the increasing obliquity of these tensions. By experiment we found that equal tensions at the following angles, produced the following difference of power in rotating the bars : \u2014\nTable H. \u2014 Power gained by a given Tension, as an intercostal Muscle, in relation to its Obliquity.\n;le of tension.\tTension.\tResistance.\nAt 90\u00b0\t2-5\t0\n\u201e 75\u00b0\t2*5\t1*50\n\u201e 46\u00b0\t2*5\t2-25\n\u201e 15\u00b0\t2\u20195\t4-25\n\u00bb 7\u00b0\t2*5\t5-50\nThe power descreases as the tension approaches the perpendicular L k', and increases as it approaches l a ; this is the maximum point : if the tension be attached to the body e e, either above a or below it, the system is changed into that of a single lever. From this we gather, that the power of an intercostal muscle, as an elevator and depressor of the ribs, increases with its obliquity; and that this movement entirely depends upon its obliquity. This is the only instance in the body where the power of a muscle increases with its obliquity.\nOf the obliquity of the ribs or bars with reference to the spine. \u2014 A given tension, say at the angle of 45\u00b0, will, when the lever is at 90\u00b0 to the spine act more powerfully than when the lever is at an angle similar to that of the ribs. We found by experiment, that the bars in the following positions required an increased power to sustain them. The tension being uniform, and the resistance to be overcome acting from the same point.\nThis gain of power is dependent upon the obliquity of the bars and change in the direction of the tension, for in each of these positions the tension was maintained the same. But if the tension be not kept uniform, still the resistance is increased as the bars rise ; thus, if the bars are at the angle of 50\u00b0 (fig' 699. m\") somewhat similar to the position of the ribs, and these under a certain tension allowed to resist a power of 4, when they are moved upwards to 90\u00b0, through which revolution the tension has kept diminishing (because it has kept shortening), it will resist a power of 5. In this we see a beautiful compensation to the muscular contraction, viz. that while an intercostal muscle is losing power as it contracts, this loss is made up by the change in position of the ribs. We feel conscious that we can exert a retaining power at the termination of a deep inspiration as great, if not\n1053\ngreater, than at any other intermediate position of the ribs, at all of which the muscular power actually exerted is greater. All these remarks apply equally if the spine be curved ; for change of obliquity of the ribs, or change of curvature of the spine to the ribs, is the same thing.\nTable I. \u2014 Change of Power, from the Obliquity of Bars or Ribs to the Spine.\nAngles of the Bars with the\nBody representing the Spine. Tension. Resistance.\n30\u00b0\t2-5\t4\n60\u00b0\t2-5\t12\n90\u00b0\t2-5\t22\n120\u00b0\t2-5\t33\nOf oblique tensions in contrary directions. \u2014 We have shown that an oblique tension between parallel levers moves them in a certain course. Now it is evident that tension in a contrary direction (all other things remaining the same) must likewise move such levers in a contrary direction. This is so clear that although Haller asserted absolutely that crossing muscles have the same action, yet he was not comfortable under such an opinion, \u201c for,\u2019 * says he, \u201c why do they cross ?\u201d\nWe have shown that a tension in the direction of l t fig. 694., will raise the bars, and one in the direction of l k will depress them ; they are, therefore, antagonistic forces, and when the tensions are similar, they produce an equilibrium of contrary force. If the bars a b, c d, (fig. 676.) be rotated, the lines will have directions contrary to each other, and will lengthen and shorten inversely to each other. Thus of the crossing tensions (fig. 676.) v d and v' b, v' b becomes shortened to n b', and v d, on the contrary, becomes lengthened to n b'; and on the other side of 90\u00b0, v D is shortened to s d, and v' b lengthened to s' b. Therefore muscles circumstanced like the intercostals and crossing each other, or observing contrary directions to each other, cannot be associates in action, for when one contracts, the other must relax, as the ribs move. We represent this more clearly in fig. 698. where a b and c d represent bars as before, rotating upon e/ e, and t t' two tensions in contrary directions. As the bars are raised towards m, t' lengthens, and if depressed towards m' it shortens, while t lengthens towards n, and shortens towards n'. We represent the tensions t t, &c., and V t\\ &c., by the white lines, in the different positions they would assume if the two bars were rotated to those places in the half circle. It w;ll likewise be observed, that while either tension gradually lengthens or shortens, the two bars pass through their maximum perpendicular distance from each other at b d, on either side of which they attain their minimum distance. Therefore, if we examine tension t at n\\ the bars would there be closer to each other than they are at bd; nevertheless, this tension in ascending must contract while the bars are increasing their perpendicular distances as they move to b d ; beyond which the tension still","page":1053},{"file":"p1054.txt","language":"en","ocr_en":"THORAX.\n1054\nshortens, while the bars now decrease their perpendicular distance. Therefore it is perfectly compatible for an intercostal fibre to separate the two ribs, between which it is attached, by its contracting ; and, if above a certain point (90\u00b0 to the spine), to approximate the same ribs by its further contraction.\nFig. 698.\nIn deep inspiration it will be found that the ribs increase the breadth of their intercostal spaces (as was mentioned years ago by Ham-berger) ; and that by the contraction of an intercostal fibre. The bars (fig. 698.) in rotating, twice attain a minimum, and once a maximum, distance from each other; while the oblique tension in that revolution once attains its maximum, and once its minimum length.\nOf tensions at different parts of the bars or ribs. \u2014 Parallel tensions of equal power produce the same effect, whether near the fulcrum or more distant from it ; an intercostal fibre near the vertebrae, has the same power as a fibre near the anterior extremity of the \u00e7ibs.\nLet Fig. 696. represent ribs as before, with two parallel tensions at different distances from the body, E e, then\nt' + \\M\u2014t'+am=t'+x(\\M\u2014a m)=t'+AO\nt + a n \u2014 t-fa n~ t + (A N \u2014 a n)=t -f A o. Therefore the tension l t ( fig. 694.) acts with\nthe same power as tensions p p', which is much nearer to the fulcra a b.\nKnowing now the effect of a single oblique tension, it is easy to consider an indefinite number of tensions, for they follow the same law of action.\nIn fig. 699. the tensions x acting on A c,. lift Fig. 699.\nthe bars to m\\ and, by the same reason, tentions observing a contrary direction and acting upon a' g' lift the bars to m'\". Therefore tensions, although observing contrary directions, may be made to conspire to the same action, and may therefore be associates when acting upon different fulcra. We have shown that tensions in contrary directions, but acting upon the same fulcra, are antagonists. If we join the levers ( fig. 699.) and increase their number, we may represent the thorax as in fig. 700., kk representing the spine, bb the sternum, the bars a a the ribs, and the bars a' a' the costal cartilages united to the bars representing ribs by a movable joint ; let r represent the external intercostals, these, we know, will act as elevators, while those at h, representing the internal intercostals, are associates in action, although they observe a contrary direction, because they act upon the fulcra in b b ; in fact, they are elevators of the levers representing the cartilages.\nWhat now is the combined action of a series of two such tensions ? The whole body of levers will be raised, and the part b b representing the sternum will have two motions : it will be raised and moved forwards into the position of b'b'. This is precisely the motion of the sternum in deep inspiration. In a model of this kind, certain means must be used to limit the motion, or the movement is continued until the tensions are at rest. Or, if the bars representing the ribs a a (fig. 700.) be fixed, then the tensions representing the internal intercostals h would depress the short bars representing the cartilages, because b b is free, and k k is fixed. And were either set of tensions continued over the joints representing the union of the cartilages with the ribs, such fibres would","page":1054},{"file":"p1055.txt","language":"en","ocr_en":"THORAX.\t1055\nantagonise each other. In nature the external intercostals are not continued over to the in-tercartilaginous spaces.\nFig. 700.\nIn this model all the ribs are elevated without the first bar being drawn up by any tension representing the scalenii muscles. In fact the fulcra are the fixed points ; therefore there are here six fixed points for the tensions to act upon, and hence each row of oblique tensions acts quite independently.\nThis application of force and disposition of the bars representing the ribs is after the manner of that great engine of power the \u201c genou lever.\u201d ( Vide Potter\u2019s Mechanics.)\nTensions in the first space {fig- 700.) act with a greater power in pushing out the body b than do the tensions in the 5th space ; but, on the other hand, the motion is less in the 1st than in the 5th space. It will also be seen that these six bars, though moving all equally, will produce an unequal effect upon the body b b, forcing out the lower end more than the upper end. The ribs of man, in the same manner, increase in their length from the 1st to the 8th, and, therefore, by an equal mobility, an unequal protrusion of the sternum is produced, advancing the lower end more than the upper end. We have reason to believe that the mobility of all the ribs is the same, and that it is by their different lengths that the diff\u00e8rent degrees of protrusion of the anterior part of the thorax may be accounted for.\nHaving investigated the effect of artificial tensions acting on bars made to represent the ribs, we can now return to the consideration of the action of the direct respiratory muscles.\nAction of the intercostal muscles (resumed).\u2014 The intercostales externi are all elevators of the ribs. Inspiratory muscles. They separate the ribs in the act, and they can do this independently of any other muscle fixing the first rib. The intercostales interni have a double action. All those portions between the ribs depress the ribs and are expiratory muscles; they also approximate the ribs and in every way antagonise the external intercostal muscles. Those portions between the costal cartilages\nare elevators of the cartilages, and associates with the external intercostals, and, thence, inspiratory muscles. These muscles also can act independently of any other muscle fixing the first or last rib.\nThe intercostal muscles being antagonists, they yield to each other, the same as any other flexor yields to an extensor muscle. We possess a perfect and definite command over the ribs, and can stop their respiratory movements at any stage of breathing, more readdy than we can those of the diaphragm.\nIt is necessary to healthy breathing that we should raise all the ribs ; they are therefore all mobile, and all their intercostal spaces are increased in their perpendicular distance during inspiration, and diminished during expiration.\nII.\tLevatores costarum {Levatores breviores costarum, Alb.).\u2014These are narrow, tendinous, and fleshy fasciculi {fig. 672.) covering the posterior end of the rib, and extending obliquely downwards and forwards, in the same direction as the external intercostals. Their superior attachment is to the extremities of the transverse processes of the dorsal vertebrae ; their inferior to the margins of the ribs between their angles and tubercles. These fibres spread out and become flat at their insertion. Each rib receives one from the vertebra next above ; there are therefore twelve muscles on each side ; and that for the first rib is derived from the last cervical vertebra. The inferior muscles of this series divide into two parts ; one of which is distributed as above stated ; but the other, consisting of longer fibres, passes over one rib and te-r min\u00e2tes on the second below ; and thus each of the lower ribs receives muscular fibres from the transverse processes of two vertebrae. The long bands have been described as separate muscles under the name levatores longiores costarum (Albinus).\nAction. \u2014The same as the external intercostals. Elevators of the ribs and inspiratory muscles. Acting directly upon their fulcra, the transverse processes of the vertebrae.\nIII.\tTriangularis s terni (Sterno-costalis, Ver-heyen). \u2014 A thin flat plane of muscular and tendinous fibres {fig. 674.) placed within the thorax, immediately behind the costal cartilages. This muscle is attached to the inner surface of the ensiform cartilage, lower part of the sternum, and the cartilages of the lower true ribs. From these origins its fibres pass laterally along the inner walls of the thorax, diverging upwards, horizontally, and downwards, and are attached by digitations (which give to the outer margin a serrated appearance) into the cartilages, lower border, and inner surface, of each of the true ribs, from the 5th to the 2nd inclusive.\nAction. \u2014 This muscle varies considerably in the extent and points of its attachment in different bodies, and even in the opposite sides of the same body. Hence, it aids in drawing down and drawing up (according to the di-","page":1055},{"file":"p1056.txt","language":"en","ocr_en":"THORAX.\n1056\nrection of its fibres) the ribs. It may be said to be both inspiratory and expiratory.\nIV. Infra-costales (Verheyen).\u2014In connection with the inner surface of the ribs (fig. 673.) several small bundles of fleshy and tendinous fibres, which are thus named, will be found extending over two, and in some instances over three, intercostal spaces. They have the same direction with the internal intercostals, and are (properly) often described as parts of those muscles. The fasciculi vary in size and number, and may be found on any of the intercostal spaces, except, perhaps, the first ; but they are most constant on the lower ribs.\nAction. \u2014 The same as the costal portion of the internal intercostals, depressors of the ribs and expiratory muscles.\nOf the elasticity of the ribs. \u2014 Elasticity depends upon reaction, and restores in a contrary direction the force which have been impressed ; the effect produced is commensurate with the amount of the cause, and the reaction can never take place so long as the cause continues to be applied ; but immediately that cause ceases, the elasticity comes into action.\nInspiration is performed by the true inspiratory muscles, and expiration, by the expiratory muscles, and the elasticity of the ribs and their cartilages, together with the elasticity of the lungs. We find a broad difference manifested between the inspiratory and expiratory power (Table R.), the latter exceeding former by about one third. This difference is due to the elasticity of the ribs and lungs associating their power with the expiratory muscles. The combined elastic power is very great ; we have examined it in two favourable cases, an hour after death, when the bodies had not fallen one degree in temperature.\nX. H., a young man, slightly built, erect and well formed, \u00e6t. 22, weight 9ist., height 5ft. 10in., vital capacity 235 cubic inches. The absolute capacity of his chest was 248 cubic inches ; internal area 256in.; circumference of the chest, over the nipples, in the ordinary state, alive 33 inches, dead 30J inches. After death we forced air into his lungs, whilst the temperature of the body was still at 97\u00b0. The force resisting the introduction of this air must havebeen due to the elasticity of the ribs and their cartilages, together with that of the lungs. By an arrangement, we could force in different quantities of air, and measure the collapsing power of the elastic parts, through the medium of the confined air pressing upon a column of mercury : the following was the result : \u2014\nTable K. \u2014 Costal elastic Collapse.\nX H.\nInch of\ncub. in.\tmercury.\nAir forced in 70 Resisting elasticity P20\nDitto\t90\tditto\t1*25\nDitto\t160\tditto\t2*50\nWe could not force in more air, for with this\npressure it was impossible to prevent the air escaping with great rapidity through the necessary wounds. This experiment was repeated three times with the same result. It will be remembered that X. H. had drawn into his lungs, when alive, 75 cubic inches of air more than we could force in, after death. If, therefore, 160 cubic inches produced a collapsing elastic force equal to 2\u20195 we may suppose that 235 cubic inches would produce an elastic force equal to not less than 3\u20189 in. of mercury. This chest,, measuring 256 superficial square inches, it follows that X. H., in breathing out 235 cubic inches of air, with no more sensible effort than that of a mere sigh, had to overcome with his inspiratory muscles a gross elastic resistance of about 499lbs., and with a force equal to this weight would the thoracic walls recoil for expiration upon the air in his lungs.\nN. C., height 5ft. 8in., weight lOst. 10lb., \u00e6t. 21: vital capacity, 200 cubic inches; absolute capacity, 245 cubic inches; superficial measurement of the entire thoracic cavity, 256 square inches ; circumference of the chest, alive, 33 inches, dead, 34\u00a3. Temperature of the body, when examined, 97\u00b0 F. Temperature of the air forced into the lungs, 63\u00b0 F. This man was what is termed \u201c thick set,\u201d firm, erect, and well built, a porter by trade, a very different case from the former. The following was the elastic power of his ribs : \u2014\nTable L------Costal Collapse in N. C.\nInch of\ncub. in.\tmercury.\nAir forced in 70 Resisting elasticity TOO\nDitto\t90\tditto\t1-50\nDitto\t180\tditto\t3*25\nDitto\t200\tditto\t4-50\nThe first ninety inches of air introduced ruptured the lungs ; therefore the elasticity of the lungs did not interfere with our experiments. In both cases this resistance must be referred only to the ribs, their cartilages and ligamentous attachments ; also, in both cases, the bodies were kept erect, or in the sitting posture ; this should be attended to, for the mere weight of the body upon the ribs when recumbent would increase their collapsing power.\nThese tables express a dead power always in reserve, equally powerful whether we are in robust health, or emaciated by age or disease. Dead or alive, this is ready to be put into force ; and, in fact, it is never at rest, never at zero, until death ; we may even go farther, and say, not until decomposition has weakened the collapsing tension of these parts. Cut through a costal cartilage, or take out a small portion of the sternum, say corresponding to the 3rd, 4th, and 5th intercostal spaces, and the opening by the elasticity of parts will retract, and we never can restore them again to their original fit, because the thoracic parietes are still not at rest. The bony cage-work of the chest is","page":1056},{"file":"p1057.txt","language":"en","ocr_en":"THORAX.\n1057\nso tightly knitted together, that at its minimum contraction there still remains an elastic force in operation. In fact we might expect this, because the respiratory movements are so small that it is necessary that an extensive elastic power should be ready at all the respiratory stages ; and therefore the parts are upon the stretch before we begin to inspire in order to increase to the geometrical degree required, of two, three, or four pounds to the inch, by a very limited movement, which would not be the case did we begin to inspire when the thoracic boundaries were at zero, at least, if it did, the walls, &c., would have to be much stronger.\nSupposing inspiration to be the result of muscular force equally distributed over the whole thorax, the inspiratory power is easily calculated. Taking the walls of the chest at 206 superficial inches, and the area of the diaphragm as 51 superficial inches, and placing them separately, it would appear as follows:\u2014\nTable M. \u2014 Inspiratory Muscular Power required to overcome Costal Elasticity, measured by the Insufflation of 200 Cubic Inches of Air. (Case, N. C.)\nAir forced into the Chest.\tResistance manifested by Inches of Mercury.\t| The same reduced to I Ounces on the superficial Inch over the Thorax.\tThe same, given as a total Force in lbs.\tTotal Power required by the Diaphragm to resist the Collapse of the Ribs, in lbs.\tTotal Powersof the Walls and Diaphragm conjoined, in lbs.\n70\t1*00\t7*8\t104-4\t24*8\t129*2\n90\t1 50\t11*7\t150-6\t37*3\t187*9\n180\t3*25\t25*3\t326*3\t80-6\t406*9\n200\t4*50\t35*1\t451*9\t111*8\t563*7\nAt the same time it must be remembered that this result is produced by insufflation which would excite an undue elastic tension in the diaphragm and abdominal muscles. Yet, on the other hand, in life a greater expansion would be produced by the ribs, and thence a greater resistance.\nIt may be questioned how far we are entitled to add a resistance as due to the diaphragm. But let us suppose a thoracic cavity collapsed to rest, with a fleshy floor or diaphragm also quiescent; let us ^suppose the ribs expanded by some power from without; the air within the chest would be attenuated, and the diaphragm would be forced upwards, by atmospheric pressure, with a force exactly commensurate to the rarefaction of the air within the chest (presupposing that no air is allowed to enter the chest when we expand the ribs). In this case the diaphragm is resisting the same force per inch as the walls of the chest. Or on the other hand, fill the chest with air to perfect distension, allow the ribs to collapse, the diaphragm would have to resist this collapse with a power exactly commensurate with the recoiling elasticity of VOL. tv.\nthe ribs ; therefore the diaphragm participates, in common, in such resistances in the thoracic cavity. But, as the question may be open to objection, we shall chiefly notice that power in reference to the parietes of the chest, given in the 3d and 4th columns in the last table. This table shows that the man, when alive, exerted a muscular power with the walls of the chest, when he inspired 200 cubic inches of air, equal to a total weight of 451*9 lbs. avordupois. Independently of the collapsing elasticity of the lungs, which would be not less than 128 lbs. more (see Table O), his inspiratory muscles lifted a weight of 32 stones, \u2014 a weight which he could not have lifted with his arms : and yet the animal economy is not conscious of this exertion. We have supposed a uniform muscular traction, which is not the case, because the distribution of muscular fibre and thoracic mobility, is not equally applied in expanding the chest. In diagram fig. 670, d represents a section of the thorax : the portion shaded is the range of thoracic mobility between extreme inspiration and expiration. The mobility is unequal ; more is on the anterior than on the posterior part ; therefore we may presume muscular traction to be more at one part than at another. This man could exhale 300 cubic inches of air ; and there is every reason to think, from this extensive mobility, according to our last estimate, that the elastic collapse of his ribs, at the termination of deep inspiration, would be not less than 1000 lbs.\nIn the superficial measurements of the thorax we have included every part, even that covering the vertebrae. Now certainly we cannot think the elastic collapse over the vertebrae equal to that from the sternum ; therefore, if we allow one-third of the chest to be inactive, and the remainder elevated by the respiratory muscles (which we think is within the mark, because every part of the chest is mobile), then in the case of N. C. in deep inspiration the muscles would have to overcome 301 lbs., or 23 ounces on the superficial square inch of the thorax.\nThe last act of life is a deep expiration. During life the ribs are always kept under a certain degree of distension, which is ready to send out from 70 to 100 cubic inches of air at any moment (Reserve air, p. 1067). Our inspiratory muscles, in fact, are always antagonising an elastic thoracic collapse ; and this is always increasing or decreasing, according to the stage of respiration, as quiescent or forced, &c. There are cases, as in hanging, where a man may die, at the moment of full inspiration, from fear, making an effort to resist the dreaded shock which he is about to receive. N. C. died thus in a state of inspiration. Making allowance for unequal elasticity of the boundaries of the thorax, of \u00a3 as above stated, it may be safely said that the different stages of respiration or breathing require the following muscular power to antagonise the elastic power of the ribs throughout","page":1057},{"file":"p1058.txt","language":"en","ocr_en":"1058\tTHORAX.\nTable N. \u2014 Inspiratory Muscular Power (corrected).\n\tDifferent stages of inspiration.\tElastic resistance in ounces on the superficial square inch to be overcome by the respiratory muscles.\tTotal resistance of the same in lbs.\n01 . I !\u00bbJ\tReserve air\t5-6\t69-6\n2*1\tBreathing air\t7*8\t104-4\n2d case N. C.\tVital capacity\t23-9\t301-0\nThus we see that in the mere act of ordinary breathing there is an elastic resistance, independently of the elastic force of the lungs, equal to more than 100 lbs. This is to be lifted 18 or 20 times every minute of our life.\nOf the Elastic Power of the Lungs. *\u2014 Independently of the powerful collapse of the ribs and their cartilages, expiration is greatly aided by the elasticity of the lungs themselves, which at all times, and in all the stages of respiration, are tending to collapse upon themselves ; and hence, immediately upon puncturing the thorax, the lungs collapse to half their dimensions.\nFrom the earliest period of physiological research, as usual, totally opposite opinions have alternately prevailed as to whether the lungs themselves are active in the respiratory movements. Averroes, Riolan, Planter, and Bre-mond*, were in favour of their independent action ; and Bartholin, Diemerhoeck, Mayow, and Haller f, opposed to it. Their elastic contractility can only have been lost sight of by reason of their quick contractible power ; for immediately the thorax is punctured, before parts are cleared away sufficiently to give a view of the contents of the thorax, the lungs have collapsed to their minimum, and a vast space is always presented between the lungs and the thoracic walls, which, by the old anatomists, even in the time of Hoadly (1740), was considered to contain air necessary for respiration.\nDr. Carson of Liverpool appears to have first noticed this elastic power of the lungs. He judiciously observes : \u201c Breathing is, in a great measure, the effect of this interminable contest between the elasticity of the lungs and the irritability of the diaphragm.\u201d +\nIn his experiments upon the lungs of some lower animals (bullocks), he found a collapsing power equal to a column of from 12 to 18 inches of water ; in a calf about 18 inches $ and in a dog about 10 inches.\nIn these experiments, the lungs, when in situ, were inflated to their maximum. Probably the ribs interfered by their resistance in aiding the collapse of the lungs. Never-\n* M\u00e9m. de l\u2019Acad. des Sciences, Paris, 1739; M\u00fcller, p. 346.\nf El. Phys. t. iii. 1. viii. p. 226.\nj Phil. Tr. 1820, part i. pp. 42, 43.\n-theless, at all times of inflation, even when the residual volume only was in the lungs, there was an elastic power in operation. Mr. Gulliver informs us, that from an examination of the lungs of man and the lower mammalia he has been led to infer that the elastic tissue is an important agent in expiration. This tissue, he says, may be seen to invest the entire surface of the lungs, forming a strong, elastic, though delicate, capsule to the organ. This investment of the lungs in the horse, he informs us, resembles the fibres of the ligamentum nuchas and the fibrous coat of the aorta of the ox, as depicted in Gerber\u2019s Anat. pp. 54, 55.\nThe longitudinal fibres which enter into the structure of the air-tubes throughout their entire extent are very elastic, like the coats of the arteries, and these are justly supposed to possess the power of contracting each minute ramification of the lungs. When this elastic power is at rest, and the lungs are collapsed to their minimum, no external pressure can discharge the remaining volume of air, because the very pressure, to accomplish this, compresses the exit tube in some part of its course. The elastic contraction of each tube acts somewhat like the vermicular motion of the intestines, causing a specific diminution of calibre upon each part of the column of air in a ramification, driving it forward. But when the elasticity has arrived at its minimum, and this tissue is quiescent, we cannot extract any more air from the lungs, because the vermicular expelling power derived from this elastic tissue ceases to act. The collapsing power of the lungs acts in the same direction as that of the ribs, but with less force.\nAccording to Tables O and P. the total elastic collapse of the male lung was equal to about 4301 grs. or nearly 10 oz. avoirdupois (9*8) upon the superficial square inch of that organ, and in the female about 5060 gr. or 11\u20183 oz. upon the superficial square inch. We think, taking all things into consideration, that it is safe to say, in making a deep inspiration for the vital capacity-volume, that we may estimate the elastic collapsing power of the lungs at one half lb. avoirdupois, per superficial square inch ; therefore, allowing the mean superficial measurement of the male lung to be 300 in. and the female 247 in., that the gross resistance, by the elasticity of the lungs against the inspiratory muscles, would be in the male 150 lbs., and in the female 123 lbs. This is to be added to the elastic force of the ribs (Table N). In the female an unknown portion of the residual volume escaped before we could connect the haemadynamometer ; for the next volume added, of 90 cubic inches in the man with all his residual volume, the collapsing power was 7*2 in., and in the female, with the addition of 100 cubic inches, it was 5*5 in., which about makes up the difference of 2 in. of collapsing power lost by the accidental escape of the residual volume.\nIn the case of two healthy persons examined immediately after death,\u2014 E. F. M., male, height 5 ft. 9 in., weight 10 st. 10 lbs.,","page":1058},{"file":"p1059.txt","language":"en","ocr_en":"THORAX.\t1059\ncircumference over the nipples, alive, 38 in. ; dead, 36 in. \u2014 died with an expiration, \u2014 we, by means of the h\u00e6madynamometer, containing water, attached to the trachea, found, with different volumes of air in the lungs, the following elastic collapsing power (temperature \u2014 of body 98'\u00f6\u00b0 Fahr. \u2014 of atmosphere 59*5\u00b0, barometer 29-753).\nTable O. \u2014 Elasticity of the Lungs (male, aet. 29.).\nElastic collapsing power,\n* Volumes of air.\tin. of water*\nResidual vol. -\t2\u20195\nReserve vol. (+90 cubic\tinches)\t7-2\nBreathing vol. ( +20\tditto)\t-8*2\nVital capacity (+25 ditto +150\nditto)......................17-0\nM. M., female; sudden death; temperature of body 97*5\u00b0 Fahr. ; \u00e6t. 28 ; height 5 ft. 9 in. ; circumference of chest over nipples 37 in.; below 32? ; lungs healthy.\nTable P.\u2014 Elasticity of Lungs (fern., \u00e6t. 28.).\nElastic collapsing power,\nVolumes of air.\tin. of water.\nResidual vol. -\t0\u20197\nReserve vol. (+ 100 cubic inches) 5 5 Breathing vol. (+100 ditto) - 10-0 Vital capacity (+ 90 ditto) 20\u20180\nAt the commencement of \u201cordinary breathing\u201d the collapsing power of the lungs in our experiment was 7-2 in., or nearly i of a lb. per superficial square inch. This is a very notable power, not less in the gross, oftentimes, than 100 lbs. of dead uncounterbalanced resistance to the respiratory muscles. In the female, with nearly an arithmetical increase of 100 cubic inches per volume, the collapsing power increases 5 to 10 and 20. The insufflated volume in the male being less regular, the collapsing power manifested is also less regular. But, taking the mean resistance of the reserve and breathing volumes in the male combined (160 cub. in.), the power of collapse was 7*7 inches. In the female, the mean of nearly the same quantity of air in the lungs (within 10 cubic inches) allowing for little or no residual volume at the starting point when we inflated, is likewise 7-7 inches. We believe that the elastic power of the lungs in the two sexes is the same ; \u2014 indeed why should it not be so? because the office of the elastic tissue is to drive out of the lungs volumes of air no longer required ; and it is probable that the resistance given by the air, against the sides of the air tubes, in both sexes, is the same; and unless the number and calibre of the air tubes are different, the resistance, by friction, to the elastic collapse of the lungs, from the transmission of similar volumes of air in the two sexes, must be the same.\nIn three experiments we found the elastic collapse of the lungs cease at different degrees; i. e. different volumes of residual air were displaced when the elastic force had come to its minimum.\n* For definition of these terms see p. 1065.\nTable Q, \u2014Volume of Residual Air displaced by the Elastic Collapse of the Lungs when the Thorax was opened, in three Males.\n\tHeight.\tWeight.\tCircum. of chest.\tWeight of Lungs.\tI Vital capa- [ city.\tVolume dis- placed.\tBronchial expansion.\n\tft. in.\tst. ll>s.\tin.\tlbs-\tin.\tin.\tin.\nH.\t5 10\t11 10\t30i\t\u2014\t240\t30\t7\nC.\t5 8\t10 10\t34i\t16f\t200\t60\t1-5\nM.\t5 9\t11 0\t36\t36\t238\t45\t12*5\nThere is no order in the numbers 30, 60, and 45, relative to the other measurements. We do not know what quantity of air remained after these volumes were displaced. When we exhausted the remainder of the residual volume, which is not affected by the elastic collapse of the lungs, the sides of the air tubes themselves collapsed by the atmospheric pressure. They likewise are elastic, but in a contrary direction; an expanding elasticity keeping them open. We found that the expanding elasticity acted so as to draw or suck inwards the air with the different powers represented by 7,1*5 and 12'5 inches of water in the h\u00e6madynamometer, when we attempted to withdraw out of the lungs more air than the lungs themselves naturally displace by their collapsing elasticity. Therefore these figures may represent the expanding elasticity of the air tubes. In these cases there is no apparent order ; but we learn the fact that such elasticity exists. In the case C there was a tubercular condition of lung, in the milliary form, in one apex ; in H there was extensive pleuritic adhesions ; but in the case of M the lungs were remarkably healthy. It is interesting to notice that there are here two elasticities in contrary directions,\u2014 an elastic collapse which has its limit at a certain point, and an elastic expansion of the air tubes, which likewise have their limit of expansion at the same point, protecting the calibre of the air tubes from any further collapse.\nIn the case of M the expansion of the air tubes was equal to 12\u20195 inches of water ; by calculation it appears that the collapse of the elastic tissue upon the vital capacity volume would be about 14 inches. These antagonistic forces are quite independent of the will, or any nervous stimuli : one is for maintaining an expiratory current of air, and the other for preserving an open channel in the lungs for inspiration.\nThe lungs are very delicate organs, and can resist but little artificial force ; for, if once inflated to the ordinary state of either the breathing volume or vital capacity volume, they do not appear able to collapse again to their original size ; \u2014 probably intra-lobular emphysema is produced.\nIn our experiments we forced air into the lungs; they were expanded because we inflated them. We now think it would be better to\n3 y 2","page":1059},{"file":"p1060.txt","language":"en","ocr_en":"THORAX.\n1060\ninflate them by expanding them (removing the external atmospheric pressure), and allow the air to drop into the air vesicles by its own gravitation (as in living respiration), when they would in all probability collapse freely to their original position. When they are inflated by expansion (the natural way of life) the delicate cells of the lungs can safely resist a force of from 3 to 9 inches of mercury, or from 40 to 121 inches of water (see next column) ; but when expanded by inflation, their collapsing power was damaged so that it could sustain only 17 or 20 inches of water. This is worthy of notice in resuscitating the apparently asphyxiated person, at which times we have long been of opinion that bellows and pumps are highly dangerous instruments to use for maintaining artificial respiration.\nOf the muscular contractility of the lungs.\n\u2014\tIn the trachea transverse muscular fibres extend across posteriorly, connecting the tips of the incomplete rings of cartilage. In the smaller bronchi they encircle the whole tubes, and there appears to be little doubt but that these circular fibres are to be found in every part of the air tubes as far as the terminal air vesicles.\nPhysiologists have disputed whether these fibres are muscular or not ; if muscular, they are important agents in respiration, acting as a series of little expiratory muscles.\nDr. C. J. B. Williams lately read a paper at the meeting of Glasgow (September 1840), upon the subject.* He experimented upon the lungs of some of the lower animals, \u2014 several dogs, a rabbit, a bullock, a horse, &c.,\n\u2014\tas soon as possible after death, submitting their lungs to galvanic stimuli, and securing a h\u00e6madynamometer with a stop-cork to the trachea. He found that, upon applying this stimulus, the fluid in the bent tube rose from 1 to 2 inches, and it immediately fell on breaking contact. This effect could only be produced by muscular contraction.\nK\u00f6lliker, a very accurate observer, confirms these views, f He found in man, in the larger and finer bronchial tubes, a coat formed of annular fibres, in one or more layers according to the size of the tube, consisting of unstriped muscular fibres ; and over this coat a thin layer of fibro-cellular tissue with nucleus-fibres. He found no muscular fibres directed longitudinally. He observes, \u201c In former observations I thought I had convinced myself of the existence of unstriped muscular fibres in the air-cells; but in my resumed examination of the lungs of man and mammalia, I can with certainty see nothing distinctly characteristic as such muscular tissue.\u201d Our knowledge of these circular muscular fibres was first chiefly derived from the researches of Reisseissen. Laennec considered spasmodic asthma to be assignable\n* The Pathology and Diagnosis of Diseases of the Chest, 8vo. by Dr. C. J. B. Williams, 1840, London, p. 320.\nf Beitr\u00e4ge zur Kenntniss der glatten Muskeln in the Zeitschrift f\u00fcr Wissenschaftliche Zoologie, H. i. S. 40. 8vo, 1848.\nto a spasm of these circular fibres. We are as yet ignorant of the possible extent of contraction of these fibres. The discharge of air is paramount, and that from the most remote vesicle ; and we know that by no mechanial means can we obtain this, and therefore a molecular power is necessary, which we readily imagine can be obtained by these tissues acting so as to give a peristaltic motion, and thus displacing from every individual vesicle the delicate stream of air necessary to be discharged. We do not need these tissues for inspiration, because the atmosphere, by its mere weight, can penetrate into the most remote air-cell, overcoming all the friction against the sides of the air-tubes. The inspiratory volumes of air are but for one purpose, to aerate the blood ; but the expiratory volumes are for the voice and other purposes sometimes requiring great force to aid in certain expulsive efforts.\nOf Respiratory Muscular Power.\u2014 Young falls into an error in supposing \u201c that in muscles of the same kind the strength must be as the number of fibres, or as the extent of the surface which would be formed by cutting the muscle across ; and it is not improbable that the contractile force of the muscles of a healthy man is equivalent to about 500 lbs. for every square inch of the section.\u201d * When we examine men we find no such calculations are to be relied upon. It is very common to find two men of corresponding dimensions produce very different effects upon any dynamic instrument.\nThe respiratory power mayor may not correspond with the general development of muscular force.\nWe have submitted 1500 men of various classes to an experiment upon the inspiratory and expiratory power. The resistance to this power was a column of mercury,\u2014th eh\u0153mady-namometer, or bent tube, first used by Dr. Hales. He observes, \u201c A man, by a peculiar action of his mouth and tongue, may suck mercury 22 inches, and some men 27 or 28 inches, high ; yet I have found by experience that, by the bare inspiring action of the diaphragm and dilating thorax, I could scarcely raise the mercury 2 inches.\u201d f Hales apparently never tested the expiratory power.\nWe connected the column of mercury with the index on a dial plate, which represented the inches and tenths of inches of mercury lifted. A tube was adapted to fit the nostrils through which the inspiratory or expiratory effort was made. By the former the index was moved in one direction, and by the latter in the contrary direction ; each half of the dial plate representing, respectively, inspiratory and expiratory power, with expressive words attached, as follow: \u2014 (See top of next page.)\nIt will be observed that the figures on each side of the same word differ in their value, those of the expiratory side ranging about one-third higher than those on the inspiratory side.\n* See Nat. Phil. Lond. 8vo, 1845, p. 99.\nf Stat., vol. i. p. 267.","page":1060},{"file":"p1061.txt","language":"en","ocr_en":"THORAX.\nTable R.\nPower of\t\tPower of\nInspiratory Muscles.\t\tExpiratory Muscles.\nT5 in.\tWeak -\t-\t2-0 in.\n2-0 \u201e\tOrdinary\t- 25 \u201e\n2'5 \u201e\tStrong\t\u2022\t3-5 \u201e\n3-5 \u201e\tVery strong\t- 4-5,,\n4-5 \u201e\tRemarkable\t- 5-8 \u201e\n5'5 \u201e\tVery remarkable\t- 7*0 \u201e\n6-0 \u201e\tExtraordinary -\t- 8*5,,\n7-0 \u201e\tVery extraordinary\t- 10*0 \u201e\nIndeed when these powers are the same, it indicates disease. We subjoin the following table of the result of these cases. (Table S.)\nTo illustrate one of the points so striking in these experiments (viz., the difference between the inspiratory and expiratory power), we refer to diagram 701., which represents by\n1061\ncurves their relative position. The upper line is the expiratory power, and the double line below, the inspiratory power. The perpendicular lines are the different heights of the cases examined. The position of these curved lines indicates the power they represent, \u2014 the higher the curve the greater the power. The two rows of figures at the bottom are the inches and tenths of inches of mercury elevated. (I. for inspiration, and E. for expiration.)\nAccording to this, at the height of 5 feet 7 inches, and 5 feet 8 inches, the inspiratory power is greatest, and thence the inspiratory power gradually decreases as the stature increases. The men of 5 feet 7 inches and 8 inches elevate a column of 3 inches of mercury : this may be considered a healthy power ; and the men of 6 feet high elevate about 2| inches of mercury as their healthy power.\nFig. 701.\nft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. 505152535465565758595 10 5 11 606 +\nExpiratory.\nInspiratory.\nE. 3-28\t3'36\t3'23\t3'15\t4'32\t4'33\t3\u201887\t4'13\t4'13\t4'28\t3'94\t363 4'48\t4'4l\nI- 2-55\t2-0\t2-52\t2-31\t2*70\t2'84\t2'70\t3-07\t2-96\t2-91\t2'83\t2-77 265\t2'67\nInspiratory and expiratory power in healthy cases.\nIt may be asked, why connect this with the height? Because it was found in six collateral observations that this was the only physical condition which presented a relation so as to throw the experiments into an orderly position.* By Table S we see that the respiratory power varies in different classes. The \u201cgentlemen,\u201d for instance, are below most of the other classes : at the height of 5 feet 8 inches, they elevate by inspiration 2\u201835 inches of mercury. This may account for the fact why Dr. Hales could only raise 2 inches of mercury by this effort.\nThe expiratory power is normally more irregular\u2014more apt to vary \u2014 than the inspiratory power. The expiratory muscles participate in other duties besides that of mere expiration ; the vocation of the glass-blower, the trumpeter, the wrestler, the jeweller (blow-pipe), and the sailor, especially call these muscles into use, increasing their natural power. They thus oftentimes become excessively strong. The inspiratory muscles are exclusively for supplying us with air, in which act they have only to oppose the uniform resistance of elasticity. The inspiratory power is therefore the best indication of the \u201chealth \u201d\u2014 the \u201c vis vit\u0153.\u201d\nAs an instance of the effect of vocation chang-\n* For the other observations, see p. 1068, and Med. Chir. Trans. 1846. Vol. 39. p. 143 et seq.\ning one of the respiratory powers and not the other, we may notice the Metropolitan police and the Thames police. The inspiratory power of these two classes is nearly equal, whilst the expiratory power of the Thames police exceeds that of the Metropolitan police,\u2014the former using their upper extremities, whilst the latter use their lower extremities most : \u2014 the former chase the thief by the use of the oar ^ the latter by the swiftness of their legs.\nCompositors and pressmen stand low the former are the lowest in their respiratory power j the pressmen are much higher. The order in which some of these classes come is as follows : \u2014 the most powerful are the Thames police ; next, the sailors ; the paupers and the gentlemen are nearly equal ; and lastly, diseased cases. The two last lines is the mean of the four healthiest classes, \u2014 the seamen, firemen, Thames police, and pugilists : their maximum is 3 inches ; the mean of the whole classes together is little more than inches. The measure of this power when expressed by inches of mercury appears small, yet, when hydrostatically considered, it is very great. Men have wondered that they could not elevate more mercury in the tube ; but all surprise vanishes when it is recollected, that, by the law of hydrostatics, when a column of 3 inches height of mer-\n3 y 3","page":1061},{"file":"p1062.txt","language":"en","ocr_en":"Table S. \u2014 Inspiratory and Expiratory Power in relation to the Stature.\n1062\nTHORAX.\nI -\t\u2014\t<\u00bb\nT <N r-i\n\u2022dxa\nI 00\n\u2022dsui\n\u2014'\tCO\n\u2022dxa\n2 8\n\u2022dsui\n(M\t\u2014\n\u2022dxa\n\u2022dsuj\n\u25a0S9SVJ\n\u2022dxa\n\u2022dsui\n\u2022ssViQ\nQ W\nh \u00db K \u00ab Ui\nO &H\nM\niB <0\n5 g\n\u00a3\u00e2\n\u00ab B\n82\nH p.\n5 B\ng S 'Si g\nOu Pi Q\na\ns\n\u00a32\na a\n\u2022dxa\t\t: \u00a7\t?\t0\tgj\t0\tOi\tx^\ts\tO cp\tr I\tCO I 2 1\n\tU :\t\u2022\t\t\t10\t\u2022\t\u2022\tCO\tCM\tTp\tCO\t\t<N 1\t\n\t13 ;\t40 :\t0\t0 CO\t0 *o\tCO\tf'-\tx^\t00\tOi tP\t^P\tO J\tTj* 1 oc I\n\u2022dsui\tU :\t%\tco\tCM\ttp\tcb\t\u2022 CM\t01\tCM\tCM\t\u00d4\tto 1\tca 1 00 l\n\u2022dxa 1\t374 3-15 5-36 2-\t41 3-\t30 2-\t52 4-\t20 3-\t36 1-81 3-00\t\n\u2022dsui\t\t -h\tOO\tCi\t\u2018C\t40\t0\tO\t40 1 \u00a7\t.\t:\t; \u00ab\t\u00a7 ^\t;\t: 9 9 9\t9\t9-? 1 ^\t:\t*\t*\tc*\t4c<N*\t\u2022\u00ab\u2014.CO\t(M\t\"\tw 1\t\u00ab1\nto\t\u2022dxa 1\tO O\t0 00\tr*\t.\t0\t00\tTP to\t8\tto\t\t.\t\t.\t0\tV* 1\tr 1\t\nO\t\t\tCM\tcb\t*\tTP\tCO\tTp\t40\tTp\t\t*\t*\t*\tTp\tCO 1\tTP 1\tTP\nO\t\u2022dsui 1\tO\t0\t40 w\t\tX\". l'-.\tTp\tCM 40\t40\ts\t\t;\t\t:\t0\ts 1\t& I\tCp\nCO\t\tcm\tCM\tCM\t\t\u00d4i\t\u00d4I\tCO\tCO\tCM\t\t\t\t\u2022\t\tCM 1\tCM j\tCM\n\t\u2022sasuQ\tto\tCM\t2\t\t\tCM\tCM\tCM\tcb\tT\t\t\t\t\t40\t1 \u00a7 1\t\u00bbO . 00\nto\t\u2022dxa\t40\t\ts\t\t00 0\t\tCO Gi\tCO\tTP GO\tO\tCi\t:\tS\ts\tGi\t1\tGO I T I\t\n0\t\t4p\tto\tCO\t\tcb\tCO\ttP\tcb\tTP\tCO\t\t\u2022\t\tCl\t^ 1\tTp 1\tTP\n-I\t\u2022dsni\tCO\tCO\tCO CO\t\tTP\t04 Ci\t40\t0\t\tCO\tO 40\t\t0 40\t0\tCM I\t40\t1 2 1\t40\n\t\t\u00f4i\tCO\tCM\t*\tCM\t*-\u2022\tCO\tCM\tCM\t**\t\t*\t\t\u00d6\tCO J\tCM 1\tCM\n\t\u2022S3SB3 )\tcm\t-\t01\tCO\tx^\t3\t\tCO\t\tCM\t\u2022\tCM\tCM\tCO\tCM\t1 2 1\tK\n10\t\u2022dxa\tto\tTp\t\u2014\t40\t\u00bbft\t2\tCi\tO CO\t\t9\t\tCM t>.\tCM\tGi 4Q\tTP\tCO 1 tp I\t' 01\n0\t\tCO\t00\tcb\t'b\tCM\tCO\t\tTp\t\t\t\tcb\tCO\t\tCO 1\tcb 1\tCO\n0\t\u2022dsui\tTP CM\t0 TP CM\t00 CM\t00 04\tx^. 0 04\tCO \u00ab0 CM\ti> CO\tCM CO\t:\tTP\t:\ts CM\tCM to CM\t\u00e6 \u00d6\t00 CM\tfc j\t& CM\n0\t\u2022S0SBQ\t00\t40\ts\t40\t40\t00\tCM\tCO\t\t-\tCM\tCO\t40\tCO\tl'-\tco 1 CO 1\tCM O\n40 0\t\u2022dxa\ti\tCO CO CO\t0 0 b*\tS TP\tx^. to cb\tCi cb\t00 CO\tCO tP 40\t:\tCO TP \u00d40\tGi CO CM\tCO Ci CO\tCO CO\t0 to\t8 I CO !\t1 21\tCO\nCi 40\t\u2022dsui\tIS 1 ^\tCi O CM\tCM Ci cm\tTP 40 CM\tTP CM\tCO 0\u00bb CM\tco\t0 40 Tp\t:\t40 CM\tO CM\tGi CM\tCM\tGi \u00f4\tCM\t00 J CM 1\ttp CM\nCi\tS0SRQ\tCi\t00\tCO Tp\t3\tX^\tCi\t-\tCO\t:\tCi\t00\t-\tOi\tGO\tto\t40 J^-\t00\n40 0\t\u2022dxa\t1 ^ 1 ^\t0 40 Tp\t0 tP\tCO CO Tf\t3-50\tob CO\tTp 9\u00b0\tto TP\t:\t3-33\tTp CO\t40 O CM\tCO J7- CM\tGO\t3-30\tCM 1\ts CO\n00 40\t\u2022dsui\t1 w\t00 0 CO\t00 04\t0 CO\ty 04\tCi CM\tN cb\tCM\t:\t00\tCO 9\u00b0 CM\tCO\ttP CM\tCM CO\tt 3 I Tp CM 1\tsi\ts CM\nCO\t*s0st?3\tTp\t40\tCi CO\tto\t04\t00\tCM\tCO\t:\t00\tN\t00\t2\tN\tto\t0 I x^ 1\tCO to\n40 0\t\u2022dxa\t1 40 1 ^\tCi 0 Tp\t0 b<\tCO TP\tX^ CO\tCO VP CO\tcp TP\t?\t:\tCM\t3-22\tGO 40 CM\tO CO\tCG\tO V CO,\tCO 1 TP I\tCO CO\n*>\u2022 40\t\u2022dsui\t1 *\"\u25a0 00 1 ^\t3-02\tCi 00 04\t0 CO\tCO 04\t<JD to CM\t40 cb\tCO E- CM\t:\tCO Oi\tTP CM\tCM to CM\tCM \u2022O CM\ts\t40 cp , CM\t1 21\tcp CM\nx^.\t\u2022S0SRO\t40\tto\trf\t2\t04\t:\tCM\t-\t:\t0\t40\tCO\t00\tTp\tCM\tCO J\tTp 0\n40 0\t\u2022dxa j\t1 s 1\tlO Ci co\t40 O TP\tTp\tS CO\t:\t\u25a0Cl to\tiO 40 cb\t:\t9 CO\tO CO\t40 Ci CM\t0 CO\tO\tCM I to 1 CM\t00 1\t40 to CO\nto 40\t\u2022dsui\t1 CO 0\t\u00d40\tO CO\t1^. Gi CM\tCO 04\t\tO Cl\t0 GO CM\t\t*5\t0 CM\tO CM\t& CM\tGi \u00d4\t40 CO CM 1\t1 II\t40 cp CM\nto\t\u2022S0S^3\t1 2\t:\t:\tCi\tto\tCM\tCO\t-\t:\tCi\t\t00\t40\tGi\t-\tOi 1 CM\t0\n40 0\t\u2022dxa\t1 40 1 w 1 ^\t:\t:\tTP CO Tp\th- CO CO\tO Ci CM\t40 N Tp\tO\t:\trc CO\t00 CM\tCM CO\tto 0 CO\t3\tCM j co !\t! II\t00 40 CO\n40 40\t\u2022dsui\t00 1\t:\t:\t8 CM\t0 Tp 04\tO X^-\tto <30 <b\tO CO\t\tCO Gi\t40 CO\tTp 0 CM\t00\tw\ts 1\t1 \u00a31\t0 CM\nir-\t*S0Stff)\t.CO\t\t\tCi\t00\t-\tco\t:\t\tO CM\tTp\tCO\tx>-\t\tl\" 1\t1 2 1\tX'\u00bb\n0 P -5 \u00bb I 0 a> \u00ab 9 B'-t: S I Sr\u00bb\" ts -5\n2JS 2J 2 = J g\nr^4--C\u00fc K t\u00ee \u00fc y\nI diseased ...[ R. ' 2M2 2.95,1411-80 2'79 6( 2-4113-19i26l2-331 3\u201836i2l[ 2-211 3-321671","page":1062},{"file":"p1063.txt","language":"en","ocr_en":"THORAX.\n1063\ncury is sustained, the force exerted by the diaphragm alone is equal to the weight of as much mercury as it would take to cover a space of the same area as the diaphragm, three inches deep. The column of mercury raised, therefore, will not safely serve to compare the respiratory power of men of different dimensions, for the area of the thorax must also be considered. For instance, we examined a man, 4 feet 7^inches high (circumference of the chest 29 inches), who raised 3*15 inches; and another man, 7 feet high (chest 50 inches in circumference), who could only elevate 3 inches of mercury : but the dissimilarity between the area of the (diaphragm in the dwarf and giant was such, that the latter in reality lifted about 500 lbs., and the former only about 39 lbs. Suppose the base of his chest to be 57 superficial square inches ; had this man raised 3 inches of mercury by his inspiratory muscles, his diaphragm alone must have opposed a resistance equal to more than 23 oz. on every inch of that muscle, and a total weight of more than 83 lbs. Moreover, the sides of the chest, by attenuating the air within, resist an atmospheric pressure equal to the weight of a covering of mercury 3 inches in thickness, or more than 23 oz. upon every inch surface, which, if we take at 318 square inches, the chest would be found to resist a pressure of 713 lbs. ; and, allowing the elastic resistance of the ribs as 1J inch of mercury, this will bring the weight resisted by the inspiratory muscles of the thorax as follows : \u2014\nDiaphragm\t83 lbs.\nWalls of the chest -\t-\t731 \u201e\nCostal resistance (elastic) - 232 \u201e Lung\t-\t-\t-\t-\t100 ,*\n1146 lbs.\nOr, in round numbers, we may say, that the inspiratory muscles of such a man of ordinary dimensions resisted 100\u00d6 lbs. This is a resistance not counterbalanced ; for were it counterbalanced, it would only be mere displacement. We have made a safe addition lor the elasticity of the lungs. We think it may be confidently stated that nine-tenths of the thoracic surface conspire to this act, allowing the remainder to lie dormant.\nAlthough the difference between the inspiratory and expiratory powers, when tested to their utmost, is so great, j et it must not be thought that these two powers are in their ordinary action so dissimilar; and indeed, when all things are considered, the question may still be asked, is the inspiratory or expiratory act the strongest? In the last table (Table S.) there is uniformly a difference, because the two powers are unequally taxed with resistance. All elastic force is co-operating with the expiratory power, whilst it antagonises the inspiratory power; therefore all the power manifested in inspiration is muscu-\nlar ; but in expiration it is partly muscular and partly elastic power. This probably causes the great apparent difference between inspiration and expiration ; at least, if we separate the resistance we assign to the elasticity of the ribs and lungs from the expiratory power, we shall nearly equalise the two. This can be easily proved upon one\u2019s own person : \u2014 partially empty the chest of air ; then forcibly test your expiration upon the h\u00e6madynamometer : probably you can only elevate the mercury inch; then inspire deeply, completely filling the lungs, and now test your expiratory power, \u2014 instead of If inch, it will probably be 5 inches. This difference appears due to two causes. 1st. In the deep inspiration the ribs are put more upon the stretch than in the moderate inspiration. 2d. The chest, when distended with air, presents points of attachment for muscular traction, to a greater mechanical advantage.\nThe most remarkable respiratory power, as tested by the h\u00e6madynamometer, was in the case of a Chatham recruit, who was frequently examined by Dr. Andrew Smith, on whose accuracy we place implicit confidence. The man\u2019s age was 18; height, 5 feet 6 inches, weight, 10 stones 5 lbs. ; circumference of his chest, 35inches; vital capacity, 230; \u2014 his inspiratory power was equal to 7 inches of mercury, and his expiratory power to 9 inches ! The thoracie power of this man, according to our last calculation, was equal to a gross weight of 2200- lbs. This was the amount manifested, and we may safely consider 50 per cent, of muscular power to be lost by the obliquity of the respiratory museies ; so that this man possessed a vital power equal to nearly 2 tons! He exhibited in no other respect any remarkable feature of strength.\nA dynamic instrument like the h\u00e6madynamometer would be useful to those whose duty it is to examine men for certain public services, as for the army, navy, police, fire-brigade, &c. With care, it would often detect disease. The efforts required to move the mercury test the whole trank of the body. The inspiratory test produces a rarefaction of the air within the thorax, causing an extra (unbalanced) atmospheric pressure upon the body from without. In this way we have detected rupture of the membrana tympani; for the air rushing in by this opening equalised the difference otherwise produced. The expiatory test is of a contrary order, increasing the pressure from within ; in this way we have detected hernia.\nThe difference between the healthy and diseased respiratory powers is broadly marked.\u2014 It is shown in the annexed diagram (jig. 702.); the lower curve is the power manifested by diseased, and the upper curve that of healthy persons. The difference is about 50 per cent., because weakness is the most prominent symptom of disease. We do not compare the expiratory power for the reason already assigned. We affix at the bottom of the diagram the relative powers in figures,\n3 y 4","page":1063},{"file":"p1064.txt","language":"en","ocr_en":"1061\nTHORAX.\nFig. 702.\nHeights. \u00a3\nft. in. ft.-in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. ft. in. [ft. in. ft. in. ft. in. ft. in. ft. in. 0 0 5051 525354 55 5 6 57 58 595 10 511 60 505152535455565758 59 5 10 5 11 6 0 6 +\nHealthy\nDiseased.\nHealthy. 2-55\t2-00\t2-52\t2-31\t2'70\t2\u201984\t2\u201870 3'07\t2-96\t2\u20199l\t2'83\t2'77\t3'65\t2 67\nDiseased. .82\t1-30\t1 16\tTOO\t134\t'74\t1-25\t'79\t1'67\tT32\t-93\t-88\t-40\t165\nInspiratory power of the healthy and diseased compared.\nOf the Respiratory Volumes. \u2014 For 1500 years, from the time of Galen to Robert Royle, naturalists, physicians, and philosophers disputed the simple operation of drawing air into the thorax. There were three explanations given :\u2014First, \u201c That by the dilatations of the chest the contiguous air is thrust away, and that, pressing upon the next air to it, and so onwards, the propulsion is continued till the air be driven into the lungs, and so dilate them.\u201d\nSecondly, That the chest is like a pair of common bellows, \u201c which comes therefore to be filled because it was dilated.\u201d\nThirdly, That the lungs are like a bladder \u201c which is therefore dilated because it is filled.\u201d\nThe great philosopher Boyle adopts the bellows\u2019 action viz., that the lungs are filled with air, because the chest is dilated, and that without the motions of the thorax they could not be filled. \u201c Indeed,\u201d says Boyle, \u201c the diaphragm forms the principal instrument of ordinary and gentle respiration, although to restrained respiration, if I may so call it, the intercostal muscles, and perhaps some others, may be allowed eminently to concur.\u201d * Cotemporary with Boyle, we find Richard Lower f (1667) correctly understanding the respiratory action; he makes a dog breathe like a broken-winded horse, by dividing the phrenic nerve. What Boyle and Lower demonstrated, every one now believes without dispute; yet it took 100 years\u2019 disputation, through a number of unfounded hypothetical and contradictory speculations, before the truths which Boyle and Lower promulgated were received. As late as the eighteenth century, little more than one hundred years ago (a. d. 1737), it was stated in the Gulstonian Lectures before the Royal College of Physicians that there was air between the pleur\u00e6 J,\u2014a condition which we now know is almost instant\n* Boyle\u2019s Life and Works, fol., Lond. 1744, vol. i. p. 64.\nf Phil. Tr. Abr., vol. i. p. 179.\nX Hoadly, Lee. on Kesp., 4to, 1740, Lond., p. 11, et seq.\ndeath. The first great epoch in the history of respiration was at the time of Harvey (1628), when he published his first work on the circulation of the blood, though at this time he did not stand commended for his discovery ; for most persons opposed it ; others said it was old ; and the epithet \u201c circulator,,\u201d in its Latin invidious signification, was applied to him. We know respiration depends upon the weight of the air; and at a very remote period air was known to possess the quality of weight. Aristotle and other ancient philosophers expressly speak of the weight of the air. The process of respiration is attributed by an ancient writer to the pressure of the atmosphere forcing air into the lungs.* Galileo was therefore fully aware that the atmosphere possessed this property ; yet when his attention was so immediately directed to one of the most striking effects of it, he did not see its connection with respiration. It was reserved for his pupil, Torricelli, to discover (1643) the true law of atmospheric pressure ; and as we can find no philosophical reason assigned, prior to this date, why air enters the lungs in inspiration, we may date this as a first step in the advance of knowledge upon our subject. Nevertheless, no less an authority than Swammerdam adopted, for upwards of twenty years after this, the unphilosophical reasoning of Descartes, that the air was forced into the lungs by its increased density around the breast, occasioned by the dilatations of the thorax, in consequence of the elevation of the ribs.\nIn 1667 some attention was paid to respiration being maintained by distinct volumes of air ; for Hook kept a dog alive with common bellows by artificial respiration, f Fabricius, in the beginning of the 17th century, correctly explained the action of the diaphragm, Borelli is the earliest physiologist (1679) who\n* Lardner\u2019s Cyclop. Nat. Phil. Hydr. and Pneum. p. 247.\nf Phil. Tr. Abr. vol. i. p. 194.\nX De Resp. ii. c. viii.","page":1064},{"file":"p1065.txt","language":"en","ocr_en":"THORAX.\nestablished an experimental inquiry into the quantity of air received by a single inspiration.* Jurin improves upon Borelli. About this time (1708) Dr. James Keile made some correct measurements of the volume of air breathed, f Then followed Dr. Hales, who threw more light upon the doctrine of air, the power of respiration, and the power of the heart, than all his predecessors ; yet he was quite ignorant of the use of respiration ; and at this period (1733) really very little was known upon the subject. In 1757 and following years, Black, Rutherford, Lavoisier, Priestley, and Scheele, the chemists of the age, threw light upon the matter by discovering the composition of the atmosphere, and consequently the composition of respired air. It is since the time of Black that the most valuable mass of our knowledge upon respiration has been discovered.\nThe functions of the thorax may be divided into two great heads, \u2014 the chemical and the physical ; for an account of the former see Respiration.\nEvery point of the thorax can move for the purpose of respiration; and hencehas followed a division of these movements, nominated after the parts which respectively carry on their functions, viz. costal breathing, and abdominal or diaphragmic breathing. These motions are, in health, symmetrical, constant, regular, sensitive, and precisely the same ; otherwise disease must exist.\nThe breathing movements are also expressive of mental emotions. The tragedian imitates them to give force to the character he represents, whether it be the stealthy breathing of the Roman conspirator sharpening his knife, or the deep swelling inspiration of Ajax defying the lightning ; these representations, without such movements, would be but dull pictures of the mind of the authors who left such characters on record. It is much easier to become delicately familiar with these movements and their characteristic differences, than it is to describe them.\nThe latitude of movement, performed by the walls and floor of the thorax, admits of three common degrees of division ; \u2014\nFirst, extreme expansion or enlargement.\nSecond, extreme contraction or diminution j and\nThird, an intermediate condition,\u2014an ordinary or quiescent state.\nThese three divisions necessarily displace volumes of air of different magnitude.\nWere the respiratory movements but two in number, extreme expansion and extreme contraction, the quantity of air moved, and the character of the movement, would be easy of calculation and expression; but the intermediate breathing or quiescent movement being so limited, so perfectly under the control of the will, so readily affected by mental emotions and by the animal functions, renders\n* De Motu Animalium, p. 2. prop 81.\nf Tentam. Med. Phys. p. 80.\n1065\nthe calculation of the volume of air ordinarily passing through the lungs a very difficult question.\nThe quantity of air in the thorax, together with those portions which can be added at will, may be arranged and denominated thus : \u2014\nFirst, residual air.\nSecond, reserve air.\nThird, breathing air.\nFourth, complemental air.\nFifth, vital capacity.\n1st. Of residual air. \u2014 After death the lungs contain air, which is not displaced by the last expiration ; this quantity remains in the thorax as long as the lungs maintain their natural structure; therefore we have no control over this volume of air ; to it we assign the term \u201c residual air.,y\n2nd. Reserve air is that portion which remains in the chest after the gentle ordinary expiration, but which may be displaced at will.\n3rd. Breathing air is that volume which is displaced by the constant gentle inspiration and expiration.\n4th. The complemental air is that volume wdrich can at will be drawn into the lungs by a violent exertion above the moderate effort of ordinary breathing, constituting the deepest possible inspiration. It is only occasionally demanded.\n5th. The vital capacity is these last three divisions combined, being the greatest voluntary expiration, following the deepest inspiration.*\nThis division of thoracic movements for commanding these different volumes of air may be more clearly illustrated by diagram 703.\nFig. 703.\nThe division of the thoracic movements.\nLet that portion marked H represent the residual volume, or air left in the lungs, after a complete voluntary expiration ; the part next\n* According to physiological nomenclature, perhaps the term \u201c vital capacity \u201d may be objectionable ; but we adopt it, for want of a better term, to signify a capacity or volume of air which can only be displaced by living movements, and may therefore be termed a \u201cliving volume,\u201d or \u201cvital capacity.\u201d","page":1065},{"file":"p1066.txt","language":"en","ocr_en":"THORAX.\n1066\nanteriorly, left white, \u2014 the reserve volume, or latitude of movement appropriated for displacing that air left in the lungs at the end of an ordinary expiration ; the black stripe next anteriorly represents the mobility for commanding the volume of breathing air ; and lastly, beyond this another white stripe shows the extreme limit of inspiration or thoracic mobility commanding the com-plemental volume of air. These last three \u2014 viz. the complemental, breathing, and reserve volumes conjointly\u2014we style vital capacity. The absolute capacity may be considered as all the divisions combined in one.\nWhatever limits the mobility of the thorax must modify the volume of air respired. This applies to any or all of the above movements. Therefore the measure of the volume of air displaced becomes a measure of the thoracic mobility ; and as disease affects the mobility of the chest, the measure of the volume of respired air becomes a measure of disease.\nThe residual volume is entirely independent of the will, and always present in the chest. The reserve volume, to use a simile, is a \u201c tenant at will.\u201d The breathing volume is constantly passing out and in, many times a minute. The complemental volume is seldom in the chest, and then only for a very brief period.\nWhatever be the breathing volume necessary for our well-being, the mobility demanded to maintain it is an intermediate mobility, just as the dark stripe infig. 703. is intermediate between the white stripes ; so that at both ends of the ordinary breathing mobility there exists a spare mobility, which we can command into action according to the necessities required. This reserve and complemental mobility may be looked upon as a broad, spare margin which encompasses our breathing ; so that any sudden exertion may not (as it otherwise would) produce painful dyspnoea and premature death.\nThis spare mobility, therefore, is always ready to admit of irregularities in the ordinary breathing, such as frequent or infrequent, quick or slow, regular or irregular, great or small, equal or unequal, easy or difficult, complete or incomplete, long or short, abdominal or costal ; as in coughing, running, laughing, crying, singing, sighing, and vociferating, many of which are but extensions or modifications of the ordinary mobility, infringing upon this margin \u2014 the complemental or reserved mobility.\nThis spare mobility is not only ready for such exigencies as above mentioned, but it becomes a reservoir for \u201ctimes of need.\u201d Thus a man can take from 230 to 300 cubic inches of fresh air into his lungs, and live upon it without inconvenience for two minutes without breathing.* The knowledge of this fact\n* It is better to inspire and expire forcibly five or six times, cleansing the lungs of the old air, and then give one deep inspiration, and there hold. For the first 15 seconds a giddiness will be experienced ; but when this leaves us, we feel not the\nwould be of much use towards rescuing a fellow creature from suffering amidst dense smoke or in an irrespirable atmosphere, as is found sometimes in mines and wells.\nA variation of this condition was once witnessed when Mr. Brunei descended to examine the breach which the river had made in the Thames Tunnel. Having lowered the diving-bell nearly 30 feet to the mouth of the opening, this was found too narrow to admit the bell ; so that no further observation could be made upon the workings, which were about 8feet or 10feet deeper: Mr. Brunei, therefore, laying hold of a rope, left the bell, = and dived himself down the opening. His companions in the bell, being alarmed at the length of his stay, now about two minutes, gave the signal for pulling up ; and the diver, unprepared for the signal, had hardly time to catch the rope, which he had let go, and was surprised to find, on coming into the bell, that he had remained below so long. On descending again, he found that he could with ease remain fully two minutes under water. In this case the atmosphere, under a pressure of 30 feet of water, charged the lungs with nearly a double volume of air compressed into the same bulk as one volume at the surface of the water. Our ordinary breathing volume can only supply us for from three to five seconds ; for if we suddenly stop breathing for that time, we experience a degree of inconvenience.\nOf the volumes of air expelled from the lungs. \u2014 A knowledge of this is of incalculable value to the physician and to the surgeon ; for disease cannot attack the lungs or the j thoracic boundaries, without diminishing the respiratory volume, which change ultimately leads to the variations of the respiratory murmurs, first noticed as a diagnostic sign of disease by Laennec. Many experimenters have measured the different volumes of respired air, not primarily in reference to disease, but merely as collateral to the observations of the chemist : hence experiments have been few, and deductions highly discrepant.\n(a) Residual volume.\u2014Dr. Hales notices this volume, but assigns no measure for it*j Allen and Pepys estimate it at 108 cubic inches in stout men of 5 feet 10 inchesf; Davy at 41 cubic inches J ; Goodwyn, by the mean of seven experiments, at 108 cubic inches ; Kite, who writes expressly upon submersion, is obscure upon this point \u00ff;\nDr. Bostock allows 120 cubic inches || ; Dunglison gives Menzie\u2019s estimate of 179 cubic inches ; Jurin estimates it at 220 cubic inches ; Fontana at 40; and Cuvier at from\nslightest inconvenience for want of air; and two minutes of time can be passed through without breathing. The most expert pearl-divers cannot remain under water for a longer time.\n* Stat., vol. i., p. 239.\nf Phil. Tr., 1809., vol. xcix. pp. 404. 428.\nj Chem. and Phil. Remarks, p. 410.\n\u00a7 Essays and Obs. Physical and Med. 1795, p. 8.\nif E . Phys. 3d. Ed. p. 318.","page":1066},{"file":"p1067.txt","language":"en","ocr_en":"THORAX.\n100 to 60 ; Mechli at 52 and 40 * ; Dr. Herbert, of Gottingen concludes this volume to be \u201cvery little.\u201d'!' We have found it to vary from 75 to 100 cubic inches. It must be relative to the absolute capacity of the chest, which varies from 248 to 457 cubic inches. The mean absolute capacity is 312 cubic inches. Allowing 100 cubic inches for the heart and large blood vessels, and 100 cubic inches for the parenchymatic structure of the lungs, will leave a little more than 100 cubic inches for the residual air; therefore Allen and Pepys\u2019s opinion may be relied upon \u00e4s very near the truth.\n(bj Reserve volume. \u2014 Goodwyn omits this volume altogether ; and this omission was pointed out forty years ago by a physiologist who himself omitted any notice of the comple)nentat air. Kite estimates this at 87 cubic inches ; Davy, by an experiment upon himself, at 77 cubic inches \u00a3 ; Dr. Bos-tock, from trials upon himself, at 160 or 170$; Mechel at 110 cubic inches.|| It averages about 100 cubic inches ; our observations range from 70 to 110 cubic inches. It is regulated by the point at which the ordinary breathing movement commences.\n(c) Breathing volume. \u2014 This has attracted most attention ; but the discrepancies of opinion are nearly commensurate with the number of observations. It would require \u00ffears of labour to determine this volume by direct experiment, in a manner to be available to the physician ; and it would require a long time to perfect the observation of it upon a single patient, because these movements are so delicately affected by the mind, so perfectly uncontrollable, and the volume is so small, that a little error would seriously damage the value of the observation. The volume assigned by observers, varying from 3 to 100 cubic inches, is as follows :\u2014\nAbildgaard -\t\tCub. in. - 3\nAbernethy -\t-\t- 12\nKeutsch\t\u00bb\u2022\t6 to 12\nGoodwyn\t-\t3 and 14\nLavoisier and Seguin\t\u2014\t- 13\nWurzer and Lametheria\t.\t8 or 10\nKite\t-\t- 17\nDavy\t-\t13 and 17\nAllen and Pepys\t\t;i65\nHerbst\t-\t16 to 25\nJurin\t-\t- 20\nBorelli\t-\t15 to 40\nHerdolt\t-\t25 to 29\nDalton\t-\t- 30\nFontana\t-\t- 35\nRicheraud, Foland, Gordon, and Ca-\t\t\nvallo\t-\t30 to 40\nHales, Jurin, Sauvages, Haller, Ellis, S\u00f6mmering, Thomson, Sprengel,\n\u25a0* Mechli\u2019s Manual Descrip, and Pathological Anat., vol. ii. p. 448.\nf Bostock, Op. Cit., p. 316 ; and Archives Gen. de M\u00e9d., t. xxi. p. 412. et seq.\nX Op. Cit., pp. 47, 48.\n\u00a7 Op. Cit. p. 316.\njj Manual of Descrip. Anat., vol. ii. p. 447.\n1067\n\u2019\tCub. in.\nBostock, Chaptal, Bell, Monro, and Blumenbach -\t-\t- 40\nMenzies\t-\t-\t-\t42 to 46\nReil\t-\t-\t- 40 to 100\nupon an average, it varies from 16 to 20, though we have occasionally found it vary from 7 to 77 cubic inches. Though our observations upon this point are but scanty compared with those we made on the vital capacity, yet from about 80 experiments we conclude that man in a perfectly quiet state, as when sitting, reading, &c., breathes much less than he does under the ordinary excitement of moving about. We think the perfectly quiet breathing, when we can scarcely perceive any movement (which is by no means uncommon), may be from 7 to 12 cubic inches, and when under ordinary excitement and exercise, from 16 to 20 cubic inches ; we have known it in one case as high as 77 cubic inches. It is probable that the quantity is relative to the volume of blood to be aerated. Herbert found that adults of smaller stature breathed less than those who were taller.* It is probable that phthisical patients breathe very little, \u2014 from 2 to 4 cubic inches ; but the number of their breathing movements is greater, which compensates for this small quantity.\n(f/) Complemental volume. \u2014 Davy, from a single experiment (upon himselfj, calculates this at 119 cubic inches f ; Kite, at nearly 200 cubic inches.^ It is regulated by the position of the ordinary breathing movement, which is intermediate between it and the reserve air. It averages, from direct experiment, rather higher than the reserve volume, \u2014 about 105 or 110 cubic inches. Taking the mean height at 5 ft. 8 in. the vital capacity is 230 cubic inches, that is to say \u2014\nReserve air -\tcub. in, - 100\nOrdinary breathing\t- 20\nComplemental\t- 110\n\t230\n(e) Vital capacity volume. \u2014 Jurin and Hales correspond in stating this at 220 cubic inches \u00a7 ; Davy at 213 cubic inches || ; and he remarks in a note, \u201c this capacity is probably below the medium. My chest is narrow, measuring in circumference but 29 inches, and my neck rather long and slender.\u201d It is probable the figures 29 are a misprint for 2 feet 9 inches round the chest. Dr. Thomson, from the mean of twelve experiments, upon men from fourteen to thirty-three years of age, states it at 186J cubic inches. Dr. Thomson himself could expel 193 cubic inches. He mentions that this volume is constant when once determined.\n* M\u00fcller, El. Phys., 1st ed. 8vo., Bond. p. 294\u00bb vol. i., 1847.\nt Op. Cit. p. 410.\ni Op. Cit. p. 47.\n\u00a7 Hales\u2019s Sat., 1732, vol. i. p. 239.\n|| Op. Cit. p. 410.","page":1067},{"file":"p1068.txt","language":"en","ocr_en":"1068\nTHORAX.\nThe temperature of the respired air is not mentioned.* * * \u00a7 Goodwyn states it at 200 cubic inchesf ; Kite, at 300 cubic inches^ ; Menzies at 200$; Bostock||, corroborated by Dun-glison^T, omitting the complemental volume, at 210 cubic inches ; lastly, Thackral, who takes this volume as the measure of health ; examines some soldiers, who give the mean of 217 cubic inches, and some shoemakers, who average 182 cubic inches ; and he remarks, \u201c a tall young cornet threw out 295 cubic inches ; this was the greatest quantity 1 ever witnessed.\u201d **\nAccording to this evidence, the respective\nvolumes are, \u2014\nResidual Reserve Breathing Complemental\nVital Capacity |\t. |)\tI\nThe apparent discrepancies of the breathing volumes are entirely due to the want of collateral observations ; for there is no distinction\nCub. in.\nvolume, from\t40\tto\t260\n\u201e\t\u201e\t77\t\u201e\t170\n\u00bb\t\u00bb\t3\t\u201e\t100\n\u201e\t\u201e\t119\t\u201e\t200\n100 \u201e\t300\nbetween the sexes, nor age, nor stature, nor weight. We have determined the vital capacity in one man as 80 cubic inches, in another 464 cubic inches ; therefore we might say this volume varies from 80 to 460 cubic inches ; but this discrepancy is cleared up, when we add that the height of the former was 3 feet 9 inches, and his weight 4 stone 9 lbs., while the latter measured 7 feet, with a weight of 22 stone ; and that if we arithmetically reduce the one to the other, the vital capacity of a dwarf is within half an inch of what it actually was, viz. 79\u201956 cubic inches by calculation, and 80 cubic inches by direct experiment. Collateral observations clear up the experiment ; thus Kite was probably a tall man, and therefore he states the vital capacity as 300 cubic inches; Davy at 213 cubic inches, because he was of shorter stature, probably about 5 feet 7 inches; Hales, Jurin, and Goodwyn about 5 feet 8 inches. We come to this conclusion, because we find this volume bear a strict relation to stature. Therefore, probably, all the observations already mentioned are correct, and only wanted another combination to remove the apparent discrepancies.\nWe have especially directed our attention to one of these volumes of air, the vital capacity.\nVital Capacity. \u2014 There are two ways of measuring the permeability of the lungs, or the volumes of air which they can displace, viz. by measuring the actual movement or mobility of the thoracic boundaries, or by directly measuring the absolute cubic inches of the volume of air expired. The former is open to an error, but the latter is not.\n* Thomson\u2019s Anim. Chem., 1843, p. 610. et seq.\n+ Op. Cit. p. 32. note.\nt Op. Cit. p. 48.\n\u00a7 Mayo\u2019s Outlines of Phys., p. 76.\n|| Op. Cit. p. 321,\n4 Ibid. vol. ii. p. 91.\n** Thackral on the Effects of Arts, Trades, &c. upon Health, p. 21. et seq.\nIf we take the movement as an index to the permeability of the lungs, we obtain an evidence only of movement, and not of the permeability of the lungs for air, for we may move the thoracic boundaries, and yet not breathe. But when we measure the volume of air, it is self-evident that this must be the measure of both the permeability of the lungs and of mobility of the thoracic boundaries, because we cannot breathe without\nmoving. The classes of persons we examined\t\t\nwere as follow : \u2014\t\tNo.\nSailors (Merchant Service)\t-\t- 121\nFire Brigade of London\t_\t- 82\nMetropolitan Police\t-\t- 144\nThames Police\t-\t- 76\nPaupers -\t-\t- 129\nMixed Class (Artisans)\t-\t- 370\nFirst Battalion Grenadier Guards\t-\t- 87\nRoyal Horse Guards (Blue)\t-\t- 59\nChatham Recruits\t_\t- 185\nWoolwich Marines\t_\t- 573\nPugilists and Wrestlers\t\t- 24\nGiants and Dwarfs\t-\t-\t4\nt, . ,\tf Pressmen\t30 1 nn ers Compositors 43 J\t-\t- 73\nDraymen -\t-\t-\t-\t-\t- 20\nGirls\t-\t-\t- 26\nGentlemen\t-\t-\t-\t-\t- 97\nDiseased Cases -\t-\t- 360\nTotal -\t-\t2430\nEach individual was subjected to\t\tthe fol-\nlowing observations : \u2014\n1st. The number of cubic inches given by the deepest expiration, following the deepest inspiration. This was taken three times, and the highest observation was noticed.\n2nd. The inspiratory power.\n3rd. The expiratory power.\n4th. Circumference of the chest over the nipples.\n5th. Mobility of the chest with a tape-measure.\n6th.\tThe\theight.\n7th.\tThe\tweight.\n8th.\tThe\tpulse (sitting).\n9th.\tThe\tnumber\tof\tordinary respirations\nper minute (sitting).\n10th. The age\n11th. Temperature of the air expired.\nTo determine these points, we constructed an air receiver, denominated \u201c Spirometer.\u201d We used a bent tube (h\u00e6madynamometer) for ascertaining the respiratory power, scales and stand for the height and weight, and a common tape-measure for measuring the mobility of the chest.\nWe rarely exceeded three consecutive observations with the spirometer, because after this the volume of respired air diminishes from mere fatigue.\nTo measure the vital capacity volume. \u2014 The Spirometer (fig. 704.), consists of a vessel containing water, out of which a receiver is raised by breathing into it through a","page":1068},{"file":"p1069.txt","language":"en","ocr_en":"THORAX.\ntube ; the height to which the receiver is raised, indicates the volume of the vital capacity.\nTo Prepare the Spirometer for Use :\u2014\n1st. Place the spirometer about three feet from the ground, upon a firm, level table. 2nd. Turn off the water-tap 4, and open the air-tap 1.\nFig. 704.\nSpirometer.\n3rd. Pour into the spout, behind, clear cold water, until it is seen to rise behind the slip of glass 3 (above the air-tube).\n4th. Slide the moveable index 2, opposite 0\non the graduated scale 13, and add more water until it is ex actly on a level with the straight edge of this index ; if too much water be poured jn, draw off, by the tap 4,\n1069\nsufficient to bring the water down to the edge of the index.\n5th. Pour a little coloured spirit into the bent tube 5, until it stands about 3\u00a3 inches, as at 6.\n6th. Turn off the air-tap 1, then suspend the counterbalance weights, 11,11, from the cord over the pullies.\nThe spirometer is now ready for an observation. The flexible tube, terminated with a glass mouth-piece, is held by the person about to be examined, and the tap 1 is to be kept open by the operator while the deep expiration is being made.\nTo discharge the air out of the receiver. \u2014 It will be seen that if the tap 1 be opened, the receiver will rise out of the reservoir by the power of the counterbalance weights, until it touches the cross-head 9. To return the receiver into its original position, the contained air must be discharged; this can be done by slowly depressing the receiver down into the reservoir, and so pressing the air out by the way it entered,\u2014through the air-tube. But, in order to do so more rapidly, a large valve at 14 admits of an instantaneous escape of the air. Therefore, to discharge the air, remove the plug 15 out of the socket 14 with one hand, while the other returns the receiver into its original position.\nLet the person to be examined loose his vest, and any other tight garment \u2014 for the least pressure from dress affects the mobility \u2014 stand perfectly erect (fig. 705.), with the head\nFig. 705.\nthrown well back ; then slowly and effectually fill his chest with air, or inspire as deeply as possible, and then he must lift the mouthpiece of the spirometer 12 to his lips, still standing in the same erect position, and place the glass mouth-piece between the lips, holding it there sufficiently tight so as not to allow any breath to escape, he then slowly makes the deepest expiration, displacing all the air he can out of, his lungs through the mouth-piece into the spirometer, where it is measured to cubic inches, and confined there by a stop-cock, until examined. This observation should be taken three times. The operator, while the experiment is going on should place his left hand upon the shoulder of the person being examined ; in this way he can determine as to the perfect inflation of the lungs and expulsion of air from them as well as the character of the thoracic expansion. The thumb of the operator should cross the clavicle, while the fingers rest on the upper","page":1069},{"file":"p1070.txt","language":"en","ocr_en":"1070\nTHORAX.\nedge of the scapula, then he feels the expanding effect of inspiration, the swelling up of the apex of the thorax.\nTo- determine the volume of air in the spirometer. \u2014 The graduated scale 13 is attached to the receiver, and made to extend downwards on the outside of the reservoir, so as always to be in relation with the index 2. On this scale 0 corresponds with the top of the receiver, or rather with the highest point to which the water can be made to rise within it. The number of cubic inches is shown by the degree upon the scale pointed to by the index 2, which corresponds with the level of the water in the receiver. But the water in the reservoir seen behind the slip of glass may not be level with the water within the receiver, just as the level of the water in a pneumatic trough may be higher or lower than the level of the water contained in a glass receiver standing upon the shelf. To know when these are level, depress the receiver until the coloured fluid in one leg of the bent tube, or inverted syphon, 5, stands level with that in the other leg, as at 6 ; then the water contained in the receiver, and that external to it, are level to each other ; and the air within the receiver is of the same density as that without.\nImmediately the plug 15 is replaced, and the hands withdrawn from the receiver, the latter will be seen to ascend some half-inch, the water behind the slip of glass to fall, and the coloured fluid in the bent tube to be unequal. This is caused by the excess of weight in the counterbalance (11, 11,), which is what necessitates the observation of the coloured fluid in the bent tubes and the correction above directed. The scale is graduated to degrees, each of which measures two cubic inches.\nTo correct the respired volume for temperature. \u2014 The table of the vital capacity-volume is calculated at 60\u00b0 Fahr. The temperature of a volume of air displaced out of the lungs into the spirometer is reduced at once to the temperature of the water in the spirometer. This, according to the season of the year, may be 50\u00b0 or 80\u00b0. Now 330 cubic inches at 50\u00b0 would occupy 337 cubic inches at 60\u00b0, and 330 at 80\u00b0, would be 317 at 60\u00b0. For eight months out of the year there needs no correction. But a correction is necessary, when a thermometer in the room stands much above or below 60\u00b0. We may estimate the change in the bulk of air as for every degree (Fahr.) of variation of temperature ; thus if a man breathe, in winter, 295 cubic inches of air into the spirometer, when the thermometer in the room stands at 55\u00b0, being 5 degrees below 60\u00b0, then = 2\u201895, must be added to the 295 cubic inches, making 297#95, or, in round numbers, 298 cubic inches. On the other hand, if the vital capacity be determined at 215 cubic inches, when the thermometer stands at 72\u00b0, which is 12\u00b0 above 60\u00b0, -g-fo = 5 must be deducted;\nmaking the corrected observation 210, instead of 215 cubic inches.\nIn the absence of the spirometer, the measure of the mobility of the ribs, by means of a common tape measure is of much value.* To measure the mobility of the thorax with a tape measure, pass the tape measure round the chest under the waistcoat, over the region of the nipples, request the person to\" inspire deeply, and note that circumference, then to expire deeply, and again note the circumference, the difference is what we term the mobility. This is a rough measurement, but of no little value in doubtful cases of chest disease. This difference, or mobility, in men of all statures should be about 3 inches, if it is found only 2\\ inches the examination should be carried further ; sometimes the mobility extends to 5\u00a3 inches, but this is excessively rare. As a general rule, when we find the mobility three inches, we find the vital capacity volume correspond with our table. Sometimes the mobility may be good, and the vital capacity bad, because, as we have already noticed, we may move the walls of the chest without breathing.\nThe vital capacity is a constant quantity ; habit will not increase it. But this volume is disturbed directly, and modified by five circumstances :\n1st, by height ; 2nd, by position ; 3rd, by weight ; 4th, by age ; 5th, by disease.\n1st. Of the effect of height.\nThe vital capacity volume bears a striking relation to the height of the individual examined ; so that, if we take a man\u2019s height, we can tell the volume of his vital capacity. We show this by a curve in fig. 710., as before ; let the perpendicular lines represent the heights increasing inch by inch from the left towards the right ; the single continuous line is the curve of the vital capacity, which gradually ascends as it passes over the perpendicular lines. The heights extend from 5 feet to 6 feet ; above six feet the observations are few. Whether the vital capacity volume maintains the same regular progression beyond this point remains to be determined. If we draw a line in a perfect arithmetical ascent of eight units for every increasing height, the line of vital capacity will be observed to run nearly parallel with it; therefore this volume increases with the increase of stature. The figures at the bottom represent the vital capacity in cubic inches, being the mean of the observations under each height. The following table (Table T.) places the subject more in detail : \u2014\nA cursory inspection of the table shows that the vital capacity increases with the height ; this is without any consideration as to age, weight, or circumference of the chest. For clearness, we arrange it in a more reduced form, as in Table U.\n* Dr. Sibson and Dr. Quain have invented some ingenious instruments for measuring the thoracic movements externally.","page":1070},{"file":"p1071.txt","language":"en","ocr_en":"Table T.\u2014Mean Vital Capacity Volume, in relation to Stature, of Fifteen different Classes of Men, or 1923 Cases, considered healthy.\nTHORAX.\n1071\n6 ft. to 6 ft. +\t\u2022S8SBQ j\tc* : \u00ab-h : : : :^\t.\t. cm\t05\tX X to I X\t80\n\tCubic inch.\tX\t.-i\t00\t03\tX \u2022<ri*oo,**x:,-X:t> 05 . x : : : x . : . cm : x\to\ta1\tto\tto X\tX\t5>\tX CM\tX\tCM\tCM\tX r- X\n5 ft. 11 in. to 6 ft.\t\u2022SaSRQ\tco cm cm\t\u2022 : oi ai h \u2022 ^ io o ^\t:\t:\tx\tCM\t\u00ab\u00ce 00 l> I X\tr-1\t112\n\tCubic inch.\tO\t<Jl\tM\tXXX\t00000*0 f~\t\"f\tX\t\u2022\t\u25a0 to IO IT5\t\u2022\t^ X \"f X n\to)\tw\t:\tiotw\u00e7q\tI\t05 X 05 X\t255 261 263 259\tX X X\n5 ft. 10 in. to 5 ft. 11 in.\t\u2022S9S1?3\tw \u00ab n n n b rt ; x x 05 x ;\tX\tCM 05\t: t-\tX .\t116\n\tCubic inch.\tx\tO\tx\tO\tx\tx\ti>\tx t>\tx\tx\tx\t'T1\tx\tx\t;\ta<\tto\t>o\tt-\t: X\tX\tX\tX\tX\tX\tX\t.\tM\tCN\t(Jt\t(N\t.\t254 236 250\tX\n5 ft. 9 in. to 5ft.l0in. ,\t\u2022SaSBQ\t00C0OllO\u00bb-i^<OC0'sf'-\u00bb00C0\t: t\u2014i\tCM\tr-x r-t\tX\tCO X X | X\tH t\u2014 H\to CM\n\tCubic inch.\tXt>XOXXO\u2019-'05XXX xx^^x^'^xx^xr- : OtCtOiOIOtOtthOlWtMOtlM \u2022\tto\tX\tX\to TJ<\tX\tTP\tCM X\t05\tCM\tCM\tX X\n5 ft. 8 in. to 5 ft- 9 in.\t\u2022S3SBQ\tho^oo^ou\u00fbh^^\u00fbw : H C'i ^ H H H Ol\t|H\t\u2022\t164 22 130 IS\to> CM X\n\tCubic inch.\tm-toO^oon'firjmxa X X X X 05. - . X X \u20141 rf w o v : OIXXX--IXXXXXXX .\t229 251 240 230\tx> X CM\n\u00f6ft. 7 in. to 5 ft. 8 in.\t\u2022S9STJ3\tiO<OCOt^OCOI>Xt>Cr\u00e7oO\u00ab-i : H <M X H\tCM\t*-h\tCM\tX <M O I J>\tX CTi\t411\n\tCubic inch.\tO)r-0CtCMNK>O(?;CO0C(O 05 X 05\tX X X \u2014M H o O : CtOKMOtiH\u00eeqoiOtMCtWlM .\t220 247 235 213\tX 05 X\n5 ft. 6 in. to 5 ft. 7 in.\t\u2022sasno\tTj- i> ^ io o o : fi n r( o n ; \u201e _\t_ _ OJ .\t.-(\tOl\t1> X X ( o\tx x \u00ab\tco X I CM\n\tCubic inch.\ttOUl^CNOO\tb^HOOM \u00ab h \u00ab !N \u00ab - ; oi o o to \u2022 \u00ce1 M ot O) W \u00ab . N !M w \u00ab w\t:\tXXX 05\tXXX X\tXXX\t<7i CM CM\n5 ft. 5 in. to 5 ft. 6 in.\t\u2022S9SR3\tX O \u20221330Nf'X\u00aba'3\t: HW .\t~\tX\tX t> o\t154\n\tCubic inch.\t5> X\tX05 X 05XXX05I> \u2014i\u2014 ;OI(\u00ab0)O)OOO)00h \u2022 05 X .\u00ab-iHHMtlHHlM\t.\t204 233 223 196\t214\n5 ft. 4 in. to 5 ft. 5 in.\t\u2022S8SR3\tCi cm ; ai o to h ^ o) : ci ^ i \u2022\tCM r-H\t.\t\u2022\tx\t\u2022 x\t1 ** X\n\tCubic inch.\t213 208 206 191 191 218 188 213 177 211\t208 216 180\t201\n5 ft. 3 in. to 5 ft. 4 in.\t\u2022S8St?3\tO\t-1\t:\tl>\t!\tX I\tJ\t5> i-l ! \u2014\t\u2022\tCO CM h\t.\t.\t.\tX\tr-l \u2022 Tfrl \u25a0 X\t73\n\tCubic inch.\tCO O\tX\t^\tX\tto\ttox .-I\t\u2022\tx\ti>\tx\tcos\t\u2022\t; x ^\t\u2022 XX\t.1-1\t.\t.r\u2014ICN\t.\t193 189 198\t193\n5 ft. 2 in. to 5 ft. 3 in.\t\u2022S8SR3\tIH :\t;\t; O X ri X ;\t: .-i X ;\t22 4\t26\n\tCubic inch.\t05\tO\t00 X\tH 00 \u2022\t\u2022\t;xxtoto\t:\t; to -h\t; x :\t:\tii-hi-ii\u2014\t-\t. \u00ab m\t.\t184 194\t189\n5 ft. 1 in. to 5 ft. 2 in.\t\u2022S8SE3\ti* i : :o\u00abi ;n :\t27 1\t1 \u00b00 CM\n\tCubic inch.\t192 162 162 176 145 202\tx i> x : :\t177\n5 ft. to 5 ft. 1 in.\t\u2022sasuo\t^ ^ H ; : :\tx >\u2014\u2022 ; \u2022\tl X\n\tCubic inch.\tto\tto X\t05 o \u2022 : : to x \u2022 ; *o : : : :\t177 167 180\t175\n\u00a9 2^\t\u2022SaSRQ\tlo::rH|>pH :::::::\t14\t\n\tCubic inch.\tH\tX \u2014' O 10 : : 2 2 x : : : : : : :\t135\tX\n3 n O\ni'SS a a\n\u2022 bin? r \u2022 \u2014 aj .t: c \u00f6 s -\u2022S' \u00ca-1 S2 \u00b0 33 <\u00a3 \u00cf \u00ab \u00a3\nS aT - u -a ^ a. o \u00a3 \u00a3\ng \u00ab3S ?x \u00ae s s yc\n% Ph G Ph S o U pLi Q u &H W\no -a\n* S3\n\u201e 3\n\u00a3 \u00dc\n33 0) .\u2014 !\u00bb bX) Jr\n3\t\u25a0\u00a3\n\u00a3.2 ca > a 3 oj\njj 8.8\ns. a 2\n8 S\nU\n~ S","page":1071},{"file":"p1072.txt","language":"en","ocr_en":"1072\nTHORAX.\nTable U. \u2014 Progression of the Vital Capacity-Volume, with the Stature \u2014 from the above.\nHeight.\t\tSeries from Observations on 1012 cases.\tSeries from Observations on 1923 cases.\tSeries in Arithmetical Progression.\n\t\t1st result.\t2nd result.\t\n5 0] 5 2 J\t[5 1\t175-0\t1760\t174-0\n5 2] 5 4 1\t(s s\t188-5\t191-0\t190-0\n5 41 5 6 J\t|- 5 5\t206-0\t207-0\t2060\n5 61 5 8 J\t[5 7\t222-0\t228-0\t222-0\n5 81 5 10 J\tj- 5\t9\t237-5\t241-0\t238-0\n5\t10] 6\t0 j\t| 5 11\t254-5\t258-0\t254-0\nMean of all 1 heights -J\t\t214-0\t217-0\t214-0\nThe first column contains the heights between five and six feet, increasing arithmetically two inches at a time, as 1. 3. 5., &c. ; the next two columns are the result of experiment ; the first upon 1012 cases at an earlier period of the investigation; the next at a later period, when the whole cases conjoined amounted to 1923 cases. We found that the men from 5 feet to 5 feet 2 in. gave a mean vital capacity of 176 cub. in.; the men two inches taller a mean of 191 cub. inches ; the next, 207 cub. in., and so on ; thus the volume increases as we descend the column. Finding the progression so regular, we arranged a fourth column, containing a series of numbers in perfect arithmetical progression, commencing with 174, and increasing sixteen at every subsequent step, corresponding to the two inches of height successively added. We found, upon comparing the two columns of observations with the column of calculation, that there was a close resemblance. The increase of sixteen for every two inches is of course the same as eight for every single inch ; hence the rule deduced upon nearly 2000 cases (and subsequently confirmed by double that number) viz. That for every inch of stature, from 5 feet to 6 feet, eight additional cubic inches of air, at 60\u00b0, are given out by a forced expiration. This brings the detailed matter of a series of tables and calculations into a point, and easy of remembrance, the more so as extended observations upon nearly 5000 men have brought the column of observation so close to the column of regular progression, that it is only necessary now to take the column of regular progression as a standard for examining the condition of the lungs as to their permeability for air, and the mobility of the thoracic boundaries.\nIf we recollect that at the height of 5 feet,\nTable V. \u2014Vital Capacity Volume (temp. 60\u00b0 F.) necessary to Health at the Middle Period of Life.\nHeight.\nft. in.\tft. in.\n5\t0\tto\t5\t1\n5\t1\t\u201e\t5\t2\n5\t2\t\u201e\t5\t3\n5\t3\t\u201e\t5\t4\n5\t4\t\u201e\t5\t5\n5\t5\t\u201e\t5\t6\n5\t6\t\u201e\t5\t7\n5\t7\t\u201e\t5\t8\n5\t8\t\u201e\t5\t9\n5\t9\t\u201e\t5\t10\n5\t10\t\u201e\t5\t11\n511 \u201e\t60\nVital\ncapacity.\n174\n182\n190\n198\n206\n214\n222\n230\n238\n246\n254\n262\n8 in. the vital capacity is 230, we can recollect the rest by adding or subtracting eight to or from this number, for every inch of stature above or below 5 feet 8 in., between 5 and 6 feet. These numbers may be taken as expressions of certain conditions of the thorax, an expression of mobility relative to breathing, and consequently an expression of the permeability of the lung. It therefore follows that whatever affects the mobility of the thoracic boundaries, or the permeability of the lungs, the amount of that cause is expressed by the volume of the vital capacity. Incipient disease is quick in affecting the vital capacity; the amount of the injury therefore is readily measured. We are at a loss to assign any just reason why the vital capacity is relative to the height, which is regulated by the length of the limbs, and not by the length of the trunk of the body. We have found by experiment, that whatever be the standing height, the sitting height is nearly the same in all persons of between 5ft. and 6ft., and if not actually the same, yet it is not a rule that the tallest men sit the highest ; for instance, one man standing 6ft. O^in. measured from his seat 2ft. 11 fin., whlie another who stood 5ft. 6in., sat 3ft. high ; therefore the length of the trunk bears no constant proportion to the length of the legs. And we found that men who stood low, breathed less than men who stood higher, but who sat the same height. Thus fig. 706. represents two men ; A. stood 4ft. 4\u00a3in., B. 5ft. 9^-in. ; they were of the same age and circumference of the chest. The weight of the short man was 7st. 2\u00a3lb., that of the taller man lOst. 3lb. Yet their sitting height was precisely the same, as is shown in fig. 707. Nevertheless, the vital capacity volume of the shorter man was 152, and that of the taller man 236 cubic inches ; so that the man who stood the shorter, but who sat as tall, if not taller, breathed eighty-four cubic inches less than the man who stood seventeen inches higher. The mobility of the chest of the taller man was nearly four inches, that of the shorter man three inches. We examined several such cases with similar results. The average vital capacity volume at all heights is about 230 cubic inches. The greatest","page":1072},{"file":"p1073.txt","language":"en","ocr_en":"THORAX.\nwe have examined was Randall\u2019s ; height 7 ft. weight 22 st. ; vital capacity 464 cubic inches. The smallest was Don Francisco; height 29 in., weight about 40 lbs. ; vital capacity 46 cubic\nFig. 706.\nRelative height of two persons standing.\n1073\ninches. The highest vital capacity at the height of 5ft. 8 in. was 330 cubic inches.\nA question arises, are the lungs and thoracic parietes at their maximum stretch when they contain the appropriate vital capacity volume? We believe not. The vital capacity of the person from whom the preparations figured above {figs. 680. et seq.) were taken, whose height was 5[ft. 4 in., weight 107 lb., was 198 cubic inches ; yet, after death, we forced 300 cubic inches of air into his lungs without rupturing them, being 102 cubic inches more than he could expire during life. Therefore there is still a spare mobility of parts, probably in reserve, to be exercised when disease attacks the lungs.\n2nd. Vital capacity affected by the position of the body. \u2014 We have said a man must hold himself erect to breathe out a good volume of air ; because the mobility of the ribs is affected by the uprightness of the spine ; and, more than this, whatever touches the ribs affects their mobility, and consequently the vital capacity. Thus, standing, we have produced a vital capacity of 260 cubic inches ; sitting erect 255 cubic inches ; recumbent \u2014 supine 230, prone 220 cubic inches ; position making a difference of 40 cubic inches. This may explain why patients with emphysematous lungs sit up in bed, and why for them to lie recumbent, is \u201csuffocating;\u201d because they thereby diminish the thoracic mobility. It may be well to recollect this effect upon respiration, in treatment of diseases of the spine, particularly at the present time, when they are\nFig. 707.\nThe relative height of the same persons sitting.\ntreated by laying the patient on the anterior pacity from 260 to 220 cubic inches, part of the chest for weeks and months to- 3rd. Vital capacity affected by weight. \u2014 gether, which position reduced our vital ca- The weight affects the vital capacity ; but VOL. iv.\t3 z","page":1073},{"file":"p1074.txt","language":"en","ocr_en":"1074\tTHORAX.\nas yet the relation does not appear so regular as that of the height. We are scarcely in a position, at present, safely to say much upon this point. As a general rule we find the weight increases with the height ; so that it is not easy to separate the effect of one from that of the other. Suppose we take two men of the same stature, say 5 feet 8 inches, the one 10 stone, the other 14 stone in weight; one of them above par, the other may be either at, or below par. If 10 stone be considered par, the 14 stone man is 4 stone in excess, or corpulent to 40 per cent. This excess weight blocks up the range of mobility, and thus, mechanically, diminishes the vital capacity volume. But let us suppose men of dissimilar heigths, one 5 feet 8 inches and the other 6 feet ; the 6 foot man should be heavier than the shorter man ; \u2014 say 3 stone heavier. This is not excess weight with him, and does not interfere with his thoracic mobility; therefore there is an inseparable relation between the height and weight. If, in a series of experiments, we sink the height entirely, and keep the mere weight in view, we shall find that the result as to the vital capacity volume is without order.\nTable W. \u2014 Vital Capacity Volume in Relation to Weight.\nWeight.\tVital capacity.\tDifference.\nst.\tst.\t\tcub. in.\n7 to 8\t166\t\n8 to 9\t187\t21\t4\n9 to 10\t199\t12 +\n10 to 11\t222\t23\t+\n11 to 12\t233\t11 +\n12 to 13\t238\t5\t4\n13 to 14\t237\t1 \u2014\n14 to 15\t278\t41\t+\nFrom this there is seen to be a rude increase of the vital capacity with the increase of the weight, but it is quite irregular, as 21., 12., 23., &c. We have also found the mean vital capacity of 147 men of 11 stone as 225 cubic inches, and that of 32 men of 14 stone, only 233 cubic inches, an increase of 8 cubic inches for an increase of 42 lbs., or 3 stone. The overwhelming effect of height disturbs the above observation ; therefore the height must be kept in view. We have calculated the weights in relation to height, with reference to the respiratory function, upon a number of men at the middle period of life. Besides the three classes mentioned above, we have included 1554 cases of healthy men in the prime of life, obligingly furnished by Mr. Brent, viz. the Oxford and Cambridge rowers, London watermen, cricketers, pedestrians, and gentlemen (Table X). The weight now appears more regular, increasing with the height, as from 92 lbs. to 218 lbs. We may make this progression appear more regular, as in Table Y, which is calculated by adding the mean weight, from the last table, of the men from 5 feet to 5 feet 2 inches (the mean of which is of course .5 ft. 1 in.), together, and taking the mean of that, which will be found 119 9 lbs.; and the\nnext from 5 feet 1 inch to 5 feet 3 inches, taking their mean as 126T lbs., and so on.\nTable X. \u2014 Weight to Height, upon 3000 cases.\nHeight.\t\t\t\t\tNo. of Cases.\tGross Weight in lbs.\tMean Wt. in lbs.\nFt.\tIn.\t\tFt.\tIn.\t\t\t\n4\t6\tto\t5\t0\t26\t2,399\t92*26\n5\t0\t99\t5\t1\t17\t1,964\t115*52\n5\t1\t99\t5\t2\t36\t4,476\t124*33\n5\t2\t99\t5\t3\t43\t5,497\t127*86\n5\t3\t99\t5\t4\t88\t12,145\t138*01\n5\t4\t99\t5\t5\t126\t17,537\t139*17\n5\t5\t99\t5\t6\t214\t31,016\t144*93\n5\t6\t99\t5\t7\t316\t45,598\t144*29\n5\t7\t99\t5\t8\t379\t57,822\t152*59\n5\t8\t99\t5\t9\t468\t73,835\t157*76\n5\t9\t99\t5\t10\t368\t61,238\t166*40\n5\t10\t99\t5\t11\t348\t59,460\t170*86\n5\t11\t99\t6\t0\t245\t43,475\t177*45\n6\t0\t99\t6\t4\t326\t71,283\t218*66\nTotal\t\t\t-\t-\t3000\t487,745\t147*86\nIt thence follows, the range of stature from 5 feet 1 inch to 5 feet 11 inches is 10 inches ; and the weight rises from 119 9 lbs. to\nTable Y. \u2014 Difference of Weight to Stature on 2648 males, from the last table.\nExact !\t\tStature.\t\tWeight lbs.\tWeight more exactly, lbs.\tDifference of Weight in lbs.\nFt.\tIn.\t\tIn.\t\t\t\n5\t1\tor\t61\t120\t119*9\t4 6*2\n5\t2\t99\t62\t126\t126*1\t+ 6*8\n5\t3\t99\t63\t133\t132 9\t+ 5*7\n5\t4\t99\t64\t139\t138*6\t4 3 5\n5\t5\t99\t65\t142\t142-1\t4 2*5\n5\t6\t99\t66\t145\t144*6\t4 3*8\n5\t7\t99\t67\t148\t148*4\t+ 6*8\n5\t8\t99\t68\t155\t155*2\t+ 6*9\n5\t9\t99\t69\t162\t162*1\t4 6-5\n5\t10\t99\t70\t169\t168*6\t4 5-6\n5\t11\t99\t71\t174\t174*2\t\n174*2 lbs., or 54*3 lbs. ; or 5*43 lbs. with every inch of stature. To subdivide the range of height it may be said : \u2014\nlbs.\tft.\tin.\tft.\tin.\nTheir rise is 6*2\tfrom\t5\t1\tto\t5\t4\n------------3*3\t\u2014\t5\t4\t\u201e\t5\t7\n------------6*5\t\u2014\t5\t7\t\u201e\t5\t11\nThere is an inequality from 5 feet 4 inches to 5 feet 7 inches in the weight ; but this would in all probability disappear if the observations were more extended ; at present it may be stated generally that the weight increases 6*5 lbs. (or 6^ lbs.) for every inch of stature from 5 feet 7 inches to 6 feet, and 6*2 lbs. for every inch of stature from 5 feet 1 inch to 5 feet 4 inches, and 3*3 lbs. for every inch from 5 feet 4 inches to 5 feet 7 inches.\nAt 5 feet 8 inches, or 68 inches of stature, the weight is 155*2 lbs., or nearly 11 stone ;","page":1074},{"file":"p1075.txt","language":"en","ocr_en":"THORAX.\n1075\nfrom this as a starting point the weight at any height may (so far as our limited observations warrant) be readily calculated. For instance, the weight is, at the height of 5 feet\n155*2\n8 inches, -\t= 2-282 lbs. for every inch of\nstature, or 27'38 lbs. for every foot of stature. The bulk or weight of bodies having the same relative proportions, is as the third power (cubes) of either of their diameters : thus, if a person 67 inches high weighs 148-44 lbs., a person 69 inches high\nshould weigh ^\nX 148-44=?\n328509\n300763\nX 148-44=\n69 X 69 X 69 67 X 67 X 67\nX 148*44= 162-14 lbs. The\nweight at that height, from observation, was 162-08 lbs., a similarity too close to be accidental.\nThe weights vary as the 2'75th power of the height, and not as the 3rd power. The relation between the two is quite close enough to show, that there is a very intimate connection between the height and the weight. The observation is made upon 1276 men at the middle period of life.\nTaking the height from 67 to 71 inches, we have as follows : \u2014\nTable Z.\u2014The calculated Weight compared with the observed Weight, according to the above Form.\nHeight in Inches.\tWeight determined by Calculation.\tWeight determined by Observation.\nin.\tlbs.\tlbs.\n67\t148-8\t148-4\n68\t155-5\t155-2\n69\t162-1\t162-1\n70\t169-3\t168-6\n71\t176-6\t174-2\nWe have found that the vital capacity increases 42 cubic inches with the weight from 100 lbs. to 155lbs., and from 155 lbs. to 200 lbs. the elfect is balanced by minus 5 and plus 5 cubic inches. In the first division there is an increase of 42 cubic inches ; the weight then comes into power, and disturbs the regular progression for the next division ; therefore we may say there is in the second division a decrease of 42 cubic inches in the vital capacity volume from the effect of weight. We repre-\nFig. 708.\nrioo\t110\t120\t130\t140\t150\t160\t170\t180\t190\n1DS-i 110\t120\t130\t140\t150\t160\t170\t180\t190\t200\nVital capacity.\nCircumference of the chests.\nThe Effect of Weight on the Vital Capacity.\nsent this by a curve, fig. 708. The continuous curve is the line of vital capacity crossing the perpendicular lines of progressive weights. The curve of volume ascends, and attains its highest at 160 lbs., and from thence it is nearly horizontal to 200 lbs. According to this, the vital capacity increases nearly in the ratio of 1 cubic inch per lb. from 105 to 155lbs., and from 155 to 200 lbs. there is no increase. This illustration of the effect of weight is calculated at one height, viz. 5 feet 6 inches ; therefore to this height only these points of weight (from ll\u00a3 to 14 stone) refer. We have noticed that the weight increases in a certain ratio with the height, and that the weight at 5 feet 6 inches affects the vital capacity in the relation just mentioned, commencing when the weight exceeds 7 per cent upon the average weight. We may, perhaps, connect this same relation with the other heights through the arithmetical progression of inch by inch. For example : \u2014 the weight of men of 5 feet 1 inch is 199*9 lbs. ; to this add 7 per cent (8 395 lbs.), making 128-2 lbs. ;\nagain, the tallest men, 5 feet 11 inches, weigh 174-2 lbs. ; to this add 7 per cent (12'2 lbs.), making 186*4 lbs. : therefore, at the height of 5 feet 1 inch a man must exceed 128 lbs., or 9 stone 2 lbs., and the 5 feet 11 inches\u2019 man 186 lbs., or 13 stone 4 lbs., before weight may be expected to diminish the vital capacity volume in the relation of 1 cubic inch per lb. for the next 25 lbs., 2% stone being the limit of our calculation. When the man exceeds the mean weight (at each height) by 7 per cent, the vital capacity decreases 1 cubic inch per lb. for the next 35 lbs. above this weight. Beyond this it is not improbable but that the decrease of the vital capacity is in some geometrical progression. Below the mean weight we have never found by experiment, that the vital capacity is affected by weight.\nThe cause of the difference of weight between men is involved in much obscurity.* We may in fact consider the usual weight of a man as his mean weight and\n* See Chambers, Gulstonian Lect. 1850.\n*3 z 2","page":1075},{"file":"p1076.txt","language":"en","ocr_en":"107G\nTHORAX.\n\u00d6JD\nc\n\u2022S'\n\u00a3\n\u00ab\nw\n<\n<\n\u2022S3SBQ\t\t\t#\t#\t.\t9\tCO\tCM\t\t*P\tvp\t>P\to\tvp\n\t\u2022\t\t\u2022\t*\t\u2022\t1\t\t\t\t\t\t\t\tCO\n\t.\t.\t.\t\t\t.\t<J)\ta\to>\t05\tCO\t\t05\t05\n\t:\t\t*\t\"\t\t*\tCO\tco\tco\tCO\tco\trH\tCO\tCO\n. o o\t\u2022\t\t\t\t\t\trH\tCM\to\trH\tI>\tCO\tvp\t,\u2014<\n2 05 O\t.5 \u25a0\t\t\t\t\t\tCO\tQC\tCM\t\tCO\tCO\tr~\tCM\nja i-i <n\td \u2019\t\u2022\t\u25a0\t*\t\u2022\t*\t*\"*\t\tCM\tCM\tPI\tCM\tCM\tCM\n\u2022S8SB3\t\t\t\tCM I\t\tCM\t\tVp\t05\t\tX 1\t[ o\tCO\tCM\n\t\t\t\t1\t\u2022\t\tCM |\t\t\t\t1\t\tr-H\tCO\n\u2022s;saq3\t\u2022\t\u2022\to\t00\t\u2022\t00\tH\t_\t1 \u00b0o\t00\tX\tX\t00\t00\n\tz\t*\t\tCO\tt\tCO\t\tco\t1 CO\tCO\tX\tX\tX\tCO\n. o o\t\u2022\t\tCO\t05\t\t00\tC35\t\t_i\tCD\tX\trH\trH\tCO\n2 do 05\t.5 \u2022\t\u2022\tCO\t\t\u2022\t\tCM\tCM\tCO\trH\t1>\t<o\tl>\tCM\nH H\td *\t:\tI\u2014*\tv-1\t:\tCM\tCM\tCM\tCM\tCM\tCM\tCM\tCM\tCM\n\u2022sasujy\t.\t\t.\t\t\tCO\t>P\tG)\tGO\t\tX\trH\t\tCM\n\t:\t\t:\t\t\t\t\t\t\t\t\tX\t\t\n\u2022sjsaqa\t\u2022\ti>\t\t00\t: I\t00\too\t00\tr- I\tCO\t~x\u2014\t1-\t1\t\n\t:\too\t\tCO\t: l\tCO\tCO\tCO\too 1\tCO\tX\tX\tco l\t1 X\n. o o\t\u2022\to\t\tCM\t\tCD\tr\u2014\trH\t00\trH\tX\trH\trH\t05\n60 00\t.5 \u2022\tvp\t\too\t\t\tOi\t\tCM\tX>\trH\tlO\tX\t\n\u00a3 pH rH\td\t\t\u2022\t\t\t\trH\t<M\tCM\tCM\tCM\tCM\t\tCM\n\u2022sasej\t\t\t\t\tCO\to\tCO\tCM\tlo\tCM\tX\tX\t\tCM\n\t\tz\t\t\t\t\t\tCO\trH\tCO\t\t\t-\tX\n\t\t\t\t\t\t\t\t\t\t\t\t\t1\t\u2022\"H\n\u2022sjsaq^\t\t\u2022\t\t\t00\tCO I\t1 CO 1\tCO\tCD\tCD\t\tCO I\t05\t<D\n\t\t\u2022\too\tCO\tco\tco I\t1 co 1\tco\tCO\tCO\tX\tCO I\tcn\tX\n. o o\t\t\trH\tIO\trH\tCM\tCO\t1>\tCM\trH\t\tC5\t05\tX>\n\u00a3 CD t'-\t\t\tx>\t\t00\tO\tCM\tCM\trH\trH\t\tvp\t1>\t\n\u00bbO rH rH\td\t\trH\t\tr\u201c\"\u2018\tCM\tCM\tCM\tCM\tCM\tCM\t<M\tca\tCM\n\u2022S3SB3\t\t\tCM\tCM\to\tO\t\t\tO\tO\to\tCO\trH\tO\n\t\t\t\t\t\tCM\tCM\trH\trH\tCO\tCM\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\tCM\n\u2022s*saq3\t\u2022\t\t\tr-\trH\t\trH\t\t\tCD\tCD\tCD\t\t\n\t*\t\too\tCO\tCO\tCO\tCO\tCO\tCO\tCO\tX\tX\tX\tX\n. o o\t\u2022\t\t\tJO\to\t00\trH\tCT1\trH\t05\too\t*T<\tCO\tX\n73 IO W\t\t\tCO\tCM\to\to\tCM\to\ti-H\tCO\tCO\tCO\t\u00abP\tCM\n\u00bbQ r-H r-H\td\t\tCM\tCM\tCM\tCM\tCM\tCM\tCM\tCM\t<M\tCM\tCM\tCM\n\u2022S3SB3\t.\t\t(M\teo\tO\te-\to\trH\to\t1 CM\tX\tvp\tCM\trH\n\t\t\t\t\tCM\teo\tCO\tX>\t1\t[ \u00ab\t\t\t\t05 CM\n\u2022s}saq3\t\trH\tco I\t1 ^ i\t\trH\t\u2022'f\t1\trH\t>P I\trH\t\tuo\tCO\trH\n\t\tCO\tco !\tI co 1\tco\tCO\tco 1\tCO\tco 1\tCO\tco 1\tX\teo\tX\n. o o\t\u2022\tcd\tCM\trH\tco\t00\tco\trH\tO\trH\trH\trH\tco\t05\nto ^ WJ ,\t\u2022S \u2022\t05\tX>\to\tO\tO\tCM\tCM\tCM\trH\tvp\trH\trfc\t\nJO r-H l-H\td *\tr-H\t\tCM\t0\u00bb\tCM\tCM\tCM\tCM\tCM\tCM\tCM\tCM\tCM\n\u2022S3SB3\tCM\trH\tCO\to\tCO\tO\to\tCM\tCO\to\tCM\tCM\tCM\t\n\t\t\t\tCM\t\tCO\trH\tCO\tCM\t\t\t\t\tc CM\n\u2022sisaq3\tCO\tCO 1\trH\t\tCO I\tCO\tCO\trH\tCO\tCO\tX\tX\tX\tX\n\tCO\tCO\tCO\tco 1\tCO 1\tCO\tCO\tCO\tCO\tco 1\tX\tX\tX\tX\n. o o\tc o\trH\tCM\trH\to\t00\tCD\t\tCO\t\tcc\tX\to\tco\nm co tF\t.5 TJH\tl>\t05\t00\t05\t00\t\t\t\tCO\to\trH\tCO\to\nX rH\tu 1-1\t\trH\tl\"1\t\tr\"H\tCM\t\tCM\tCM\tCM\tCM\tCM\tCM\n\u2022S3SB3\tCM\tCM\tCO\tIs-\tlo\tCD\trH\tCM\t05\tCO\tCM\t\t\t\n\t\t\t\t\u25a0\"*\tr\"H\t\tCO\t\t\t\t\t\t\t\n\u2022sisaq3\trH\tCM\tCM I\tCM\tcm\tCO\tCM\tCM\trH I\tI CM\t1 l-H\t\t\t<M\n\tCO\tCO\t00 1\tCO\tCO\tCO\tCO\tCO\tco 1\t1 CO\t1 X\t\t\tX\n. o o\t\u2022 1\to\tg\tlO\tCM\tCD\tCT)\tvp\to\tr-H\t\t\t\tCD\n</5 CM X\t\u2022S rH\t00\t\to\t00\tO\t\t\to\trn\tX\t\t\t05\npQ\tr-H\td\t\tP\"H\t7*\t\trmml\t(M ;\tCM\tCM\tCM\t\t\t\t\n\u2022sasB3\tCO\t\u00ae 1\t\tCO\tCM\t* 1\tco\t\u00bbP\t\t~ 1\trH\t\t\tCD rH\n\u2022s}saq3\t1\tr\u2014H\tCM\t1 r H\tCM\trH\tCO\tCO\trH\t| CO\t1 r H 1\tt o\t\t1 ! 1\t1 r-H\n\t1\tCO\tCO\t1 CO\tCO\tCO\tCO\tCO\tCO\t1 CO\t1 CO 1\t1 X\t\t1 : 1\tX\n. o o\tc ^\tco\t05\trH\t00\tO\too\too\tCD\to\tlO\t\t\tCD\nW H (N\t.\u00a3 oo\t>p\tCD\t00\tCD\tI>\tcn\tCM\t05\to\t05\t\t\tX\nrH r-H\td\t1-1\tr\u201c1\t\trH\trH\t\tCM\t\tCM\t\t\t\t\n\u2022S3SB3\tCO\t| 00\t1\t100\tCM\t\t:\t\t\t:\t:\t\t\tr>\n\u2022s^saq3\tO CO\tCO\to CO\to CO\t05 CM\t:\t\t\t\t\t\t\t\t\"o X\n\u25a0 \u00a3 \u00ae\tC t-\t00\tCO\t00\t00\t\t\t\t\t\t\t\t\tCD\n\t.5 t-\tx>\tI>\t00\tCD\t\u2022\t\t\t\t\t\t\t\tI>\nj\u00fb 2\t^\tu\tr-H\t\trH\trH\t\u2022\t\u2022\t\t\t\u2022\t\t\t\t\n\tin. 1\tcm\tCO\trH\t\u00ab5\tCO\t\t00\t05\t01\t\tO\t+\ti\n42\t. xt bp\t*\" o\tVO o -M\t*o p\to\tO\tVp o \u2022M\tip o\tlO o +->\tvp O\t\u00bbP o\tip O\t<D O\tCO o\t\u00a7 O B\n\u2018S3 w\t\u00e0 O\t1\u20141\tCM\tCO\tTj*\tip\tCO\t\t00\t05\to\trH\to\t\n\t\t\t\t\t\t\t\t\t\t\t\trH\t\to\n\td 1p\tVO\tVO\t*0\tVO\t\u00bbP\t\u00abP\t\tVp\t\u00bbP\tvp\t\tCO\tH\nthe term \u201cgained weight\u201d should be understood as weight superadded to his usual weight, or mean weight in the above Table. Thus, if a man may lose weight below his usual weight, he should gain above his usual weight before he can be said to have gained tueight.\nThe effect of weight in diminishing the respiratory volume, need not*in the least disturb the observer, when te sting the lungs through the measurement of the vital capacity, with re-\nference to phthisis or any other chest disease. For collateral observations and the history of the case, will sufficiently protect him'from such difficulty. We see that the weight increases at so much per inch ; we have no doubt that by extended observations it will be found to be regular through the whole series of heights, and that it will be found to increase 7 lbs. for every inch of stature. We know that the respiratory power increases in a similar arithmetical relation. We do not mean that","page":1076},{"file":"p1077.txt","language":"en","ocr_en":"THORAX.\n1077\nthe lb. will correspond to the inch, for that is accidental, merely depending upon the units employed, but that the increase of each will be found in an arithmetical progression, and hence, probably, the reason why tall men breathe more than short men.\nBut the weight can never be the sure guide that the height is, because the former varies at any time in life, even in a few days ; whereas the latter varies only at the extremes of life.\n4th. Relation of vital capacity to the circumference of the thorax.\u2014 We notice this here, because the question is so natural, \u201c Has the size of the chest no relation to the vital capacity?\u201d We do not find that there exists any direct relation between the circumference of the chest and the vital capacity. We have found \u2014\nHeight. Circum.\tVital\nMen.\tft.\tin.\tin.\tcapacity.\n11\t5\t8\t35\t235\n10\t5\t8\t38\t226\nTherefore, the men with chests 3 inches larger, breathed 9 cubic inches less, or 21 men of the same height, but of different-sized chests, breathed a mean vital capacity of 230 (the due quantity according to Table T). We have consolidated the following result upon 994 cases, the height is kept in view, calculated at 5 feet 6\u00a3 inches.\ndimensions and the vital capacity ; if, for instance, one man has a chest 35 inches in circumference, and 3 inches mobility, and another man has a chest 40 inches in circumference, and 4 inches mobility, then the latter will surely displace a larger volume of air than the former, but omitting this, we expect as large a vital capacity from a man with a thin and narrow thorax, as from a man with a broad and deep thorax. In fact, aeration need have no relation to the thoracic dimension ; and, for the same reason, the size of the chest no relation to the vigour of the whole man. Indeed we incline to the contrary, viz. that it is most likely the respiration is most vigorous in the narrow-chested man, when the mobility is greatest. The vigour of the lungs, like every other organ in the body, we believe, has no relation to the dimensions. One person may have a brain 1 lb. lighter, or \u00a3 less than another person, and yet their capacity and mental qualities shall not appear different.\n5th. Vital capacity affected by age. \u2014 Age affects the breathing movements, but less remarkably than the height and weight. Indeed the influence of age was not apparent in the first calculation upon 1012 cases, nor until we took a basis of 1923 cases. Time affects life in two ways, first bringing it to perfection, and then determining (hat perfection.\nTable B B. \u2014 Circumference of the Chest/in Relation to the Vital Capacity Volume, in 994 cases (Males).\nCircumference of Chest.\t\t\tVital Capacity.\tNumber of Cases.\tCubic In. Difference.\n30\tto\t301\t200\t14\t\u2014 13\n30\u00a3\t99\t31\t187\t20\t+ 18\n31\t99\t311\t206\t21\t\u2014 10\n34\t99\t32\t196\t35\t+ 1\n32\t99\t321\t197\t32\t\u2014 7\n32i\t99\t33\t204\t50\t\u2014 2\n33 \"\"\t99\t331\t202\t44\t0\n33i\t99\t34\t202\t63\t+ 63\n34\t99\t34i\t213\t70\t+ 4\n34i\t99\t35\t217\t78\t\u2014 2\n35\t99\t35i\t215\t71\t+ 14\n354\t99\t36\t229\t74\t\u2014 10\n36\t99\t36i\t219\t59\t+ 2\n364\t99\t37\t221\t97\t+ 18\n37\t99\t371\t239\t59\t\u2014 4\n371\t99\t38\t235\t57\t\u2014 13\n38\t\t381\t222\t41\t+ 8\n38i\t99\t39\t230\t40\t\u2014 6\n39\t99\t391\t224\t18\t+ 2\n391\t99\t40\t228\t37\t\u2014 11\n40\t99\t40i\t217\t14\t0\nThere is nothing in this table to confirm that which we had thought would be the main guide to the vital capacity volume ; thus, compare together the first and last 14 men whose chests differ 10 inches, and their vital capacity only 17 inches ; or compare together the first and last columns, the one is perfectly regular and the other most irregular. There is a certain rude relation between the thoracic\nTable C C. \u2014 Effect of Age, from Observations on 1775 healthy Men. the Height being kept in View.\nAge.\tCubic Inches.\tCases.\n15 to 20\t220\t283\n20 \u201e 25\t220\t491\n25 \u201e 30\t222\t347\n30 \u201e 35\t228\t242\n35 \u201e 40\t212\t171\n40 \u201e 45\t201\t93\n45 \u201e 50\t197\t55\n50 \u201e 55\t193\t37\n55 \u201e 60\t182\t30\n60 \u201e 66\t183\t26\nMean of all\t\t\nages\t205-8\t1775\nS J\nO\u00dc\n\u2018o\u00ae 2.* \u00ab3 U O Q)\n341\n34\tJ 341\n35\tJ 341\n35\tJ 351\n36\tj 361 35 J\n220\n225\n206\n195\n182\n35\n+ 5\n\u2014\t19\n\u2014\t11 \u2014 13\nThe column of \u201c difference \u201d exhibits the effect of time upon the breathing volumes.\nFrom 15 to 35 years of age the vital capacity is increased, and from 35 to 65 years of age it is decreased in the progression of 19, 11, and 13 cubic inches. We illustrate this by a curve in\u00dfg. 709. The curve of the vital capacity will be seen to rise slightly as it passes the perpendicular lines of years until it comes to 35 years of age, after which it keeps declining as it cuts all the succeeding lines of quinquennial periods down to 65 years. We may say, therefore, that the vital capacity increases with the age up to\n3 z 3","page":1077},{"file":"p1078.txt","language":"en","ocr_en":"1078\nTHORAX.\nFig. 709.\nYp.ro fis\t20\t25\t30\t35\t40\t45\t50\t55\t60\n120\t25\t30\t35\t40\t45\t50\t55\t60\t65\nVital capacity.\nThe Effect of Age on the Vital Capacity.\n30 years, and from 30 to 60 it decreases 43 cubic inches, or P43 (nearly li cubic inches) per year, or 7 cubic inches in 5 years, or 14\u00a3 cubic inches in 10 years. Although this appears by calculation, yet we do not strictly follow this ratio, as we find by experience that the effect of age may be more diminished, as follows : \u2014\nTable D D. \u2014 Vital Capacity at three Periods of Life, from 4800 cases (males).\nHeight.\t\t\tVital Capacity. Age from 15 to 55.\tVital Capacity. Age from 55 to 65.\tVital Capacity. Age from 65 to 75.\nft.\tin. ft.\tin.\t\t\t\n5\t0 to 5\t1\t174\t163\t161\n5\t1 \u201e 5\t2\t182\t173\t168\n5\t2 \u201e 5\t3\t190\t181\t175\n5\t3 \u201e 5\t4\t198\t188\t182\n5\t4 \u201e 5\t5\t206\t196\t190\n5\t5 \u201e 5\t6\t214\t203\t197\n5\t6 \u201e 5\t7\t222\t211\t204\n5\t7 \u201e 5\t8\t230\t219\t212\n5\t8 \u201e 5\t9\t238\t226\t219\n5\t9 \u201e 5\t10\t246\t234\t226\n5\t10 \u201e 5\t11\t254\t242\t234\n5\t11 \u00bb 6\t0\t262\t249\t241\nFrom 55 to 65 we have deducted 5 cubic inches per cent, and from 65 to 75 years of\nage 8 cubic inches per cent. We have not brought in the effect of time before the age of 55 years. This is supposed to be at the mean weight. The first column is derived from observation, the two second are derived from calculation.\n6th. Of the effect of disease upon the vital capacity. \u2014 The effect of disease upon respiration was well known to Boerhaave and Morgagni, they considered that the disturbance of any organ in the body would disorder the whole function of respiration. Morgagni devotes more than one-sixth of his celebrated work, the \u201c Seats and Causes of Disease,\u201d \u201c to diseases which affect respiration.\u201d We may safely say all thoracic and abdominal diseases, as tumours, abscesses, and acute inflammations, will affect the respiration. Of the different respiratory volumes, we select that one which requires the most extended mobility, viz. the vital capacity, which becomes altered to an extent commensurate with that of any disease physically affecting our respiration, it is therefore a test of the presence and extent of such diseases. Such movements as command this volume, extend from the neck to the plantar muscles of the feet.\nOne condition which we have been accustomed to look upon as affecting our breathing, does not affect it, viz. old pleuritic adhesions.\nFig. 710.\nft. in. ft. in.\tft. in.\tft. in.\tft. in.\tft. in.\tft. in.\tft. in.\tft. in\tft. in. !t. in. !t. in.\tft. in.\tft. in\nS 50\t5 1\t52\t53\t54\t55\t56\t57\t58595 10\t5 11\t60\nM eights. |50\t51\tgy\t53\t54,\t55\t5 g\t57\t5 g\t59 5 10 5 11\t6 0\t6 +\nHealthy.\nDiseased.\nHealthy. 143 175 177 Diseased. 69 100 101\n189\t193\t201\t214\t229\t223\t237\t246\t247\n102\t103\t78\t120\t98\t130\t111\t96\t130\nVital Capacity oj the healthy and diseased Cases compared.\n259\t276\n114\t106","page":1078},{"file":"p1079.txt","language":"en","ocr_en":"THORAX.\t1079\nWe met with a ease in which the lungs meal will even make a difference in the thora-\ncould not, in consequence of pleuritic adhe-sions, be removed from out of the thorax; indeed there was not one square inch of pleura which was not firmly adherent. The lungs had to be torn out by little pieces, and so strong was the adhesion to the diaphragm, that in removing them this muscle was ruptured, yet the living respiratory mobility of the thoracic walls exceeded by three inches the whole thoracic space allotted for the heart and lungs, as measured after death. This space to the mobility was as 248 to 251. In other respects the lungs were healthy.\nOf all diseases, phthisis pulmonalis most readily affects the vital capacity, not only when the lungs are beginning to be infiltrated with tubercular matter, but probably before this.\nThis is shown in fig. 710. Taking all the cases together, the difference is about 50 per cent.\nThe effect of this disease upon the vital capacity in the case of Freeman was very remarkable. This man came from America in 1842 \u201ctrained for a prize fight.\u201d He was examined when in his \u201c best condition,\u201d and his vital capacity measured 434 cub. in. (temp. 60\u00b0) ; height, 6 ft. Ilf in. ; weight, 19st. 5 lbs. ; circumference of the chest, 47 in.; inspiratory power, 5*0 in. ; expiratory power, 6*5 in. Freeman fought his battle, and for the subsequent two years lived a rambling and dissolute life. In November, 1844, exactly two years afterwards, he came to town in ill health. At this time there was no auscultatory evidence of phthisis pulmonalis ; but the following difference appeared in his vital capacity-volume.*\nVital\nCapacity.\nWeight.\ncub. in.\nst. lbs.\nNov. 1844 -\nIn October, 1845, he died at the Winchester hospital ; and Mr. Paul, surgeon to that charity, stated that Freeman died of extreme exhaustion and debility, expectorating pus ; and that his lung was throughout studded with tubercles ; his weight at death was 10 st. 1 lb.; height, 6 ft. 7^ in. Another remarkable case was that of a man of perfectly healthy appearance, and in whom there was no auscultatory or general sign of organic disease, but whose vital capacity was deficient by 47 cub. in.; and it was found, within three days of the time when he was examined, that the left lung at the apex was studded with miliary tubercles, the whole not extending beyond a square inch.\nIn diseases of the spine, particularly in angular curvature, the mobility is changed Sometimes to such a degree that the vital capacity is diminished to 20 cub. in. A full\ncic mobility, of from 12 to 20 cubic inches. If the vital capacity is deficient, there must be some cause producing the effect. It may or may not be in the thoracic cavity. Collateral observations must point more definitely to the diseased part. The spirometer is only a gauge to measure the mobility and permeability of the lung; other circumstances must point out the cause of the mobility and permeability being affected. Taking the observations upon the diseased cases by calculation, the vital capacity volume may be arranged for all heights as follows : *\nTable E E.\u2014Effect of Phthisis Pulmonalis upon the Vital Capacity.\nHeight.\t\t\t\t\tHealth.\tSuspicious Cases, 16 per Cent.\t1st Stage. 33 per Cent\t2d Stage.\tMixed. 43 per Cent.\nft.\tin.\t\tft.\tin.;\t\t\t\t\t\n5\t0\tto\t5\tl\t174\t146\t117\t82\t99\n5\t1\t55\t5\t2\t183\t153\t122\t86\t102\n5\t2\t99\t5\t3\t190\t160\t127\t89\t108\n5\t3\t55\t5\t4\t198\t166\t133\t93\t113\n5\t4\t99\t5\t5\t206\t173\t138\t97\t117\n5\t5\t99\t5\t6\t214\t180\t143\t100\t122\n5\t6\t99\t5\t7\t222\t187\t149\t104\t127\n5\t7\t99\t5\t8\t230\t193\t154\t108\t131\n5\t8\t55\t5\t9\t238\t200\t159\t112\t136\n5\t9\t99\t5\t10\t24b\t207\t165\t116\t140\n5\t10\t99\t5\t11\t254\t213\t170\t119\t145\n5\t11\t99\t6\t0\t262\t220\t176\t123\t! 149 1\nThe question naturally arises, How far deficient of the standard may be the vital capacity without indicating disease ? It has been found that ten cubic inches below the due quantity, i. e. 220 instead of 230 inches, need not excite alarm ; but there is a point of deficiency in the breathing volume at which it is difficult to say whether it is merely on\u00e7 of those physiological differences dependent on a certain irregularity in all such observations, or deficiency indicative of disease. A deficiency of 16 per cent, is suspicious. A man below 55 years of age breathing 193 cub. in. instead of 230 cub. in., unless he is excessively fat, is probably the subject of disease.\nIn phthisis pulmonalis the deficiency may amount to 90 per cent., and yet life be maintained. The vital capacity volume is likewise a measure of improvement. A phthisical patient may improve so as to gain 40 upon 220 cub. in.\nOf the Respiratory Movements.\u2014The breathing volumes have been divided into three kinds ; so likewise the breathing movements admit of a similar division,\u2014one ordinary and two extraordinary movements.\nBy the independent action of the intercostal muscles, every intercostal lamella can act separately, therefore we have the thorax furnished with 22 spaces by which it can enlarge ; and\n* See \u201cSpirometer Observations,\u201d First Report of the Hospital for Consumption, p. 23. et seq. Lond. 1849.\n3 z 4","page":1079},{"file":"p1080.txt","language":"en","ocr_en":"1080\nTHORAX.\nthe diaphragm acting as one muscle, makes 23 mobile regions for respiration.\nThe respiratory movements of health may be classed as costal and abdominal. The character should be established by the order in which they follow each other. In health the walls of the thorax and the floor do not dilate simultaneously but consecutively. The character of\u201c the breathing\u201d cannot always be told by the eye, but it can always be determined by the touch. If we stand behind a patient, when seated and leaning against the back of the chair or against our person, and pass the right arm over the shoulder, extending it over the anterior part of the chest, until the hand rests upon the abdomen over the umbilical region, we command a delicate index of the breathing movements. It will then be found, that in ordinary male breathing the abdomen first bulges outwards ; the ribs and sternum nearest the abdomen gently follow this movement, until the motion, like a wave, is lost over the thoracic region. The undulation commences at the abdomen. This is aoaomina, or diaphragmatic respiration. We here have costal motion, but as the ribs moved second it is not called costal breathing.\nIn costal breathing the upper ribs move first, and the abdomen second. This is the ordinary breathing in women.\nAll difficult, sudden, and extraordinary breathing is costal ; we at such times direct all our power towards the apex of the thorax, first expanding that region, and gradually those below it.\nWhen we determine the order of breathing by the sight, we must be careful to take the position of the body into account. If the patient be recumbent (supine), we may notice extensive costal motion, and, indeed, it may be true costal breathing ; but place the patient erect, and the breathing may be diaphragmatic. When recumbent, all the motion is thrown forwards, the natural backward and lateral motion of the ribs being prevented ; and so sensitive are the breathing movements to impediments, that they may either take a reverse action, or all the motion being thrown forwards, will give a preternatural movement of the ribs, which may be mistaken for costal respiration.\nProfile view of the breathing movements \u2014 (a) Ordinary breathing (Male). \u2014 Fig. 711 was obtained by tracing the shadow of a man on paper. The back was fixed, so as to throw all the movement forwards. The anterior black, continuous line represents the ordinary breathing. This line is thicker over the abdomen than elsewhere. The anterior margin of this line indicates the boundary of the ordinary inspiration, and the posterior margin the boundary of the ordinary expiration.\n(Female). \u2014 This is represented by the anterior continuous line in fig. 712., in the same manner as shown in the male. This line in the female is broadest over the sternum, and narrow over the abdomen. The movement over the abdomen of the female is so small, that the number of the respirations cannot\nFig. 711.\nRespiratory Movements. Male.\nDeep inspiration, dotted line; ordinary state, continuous line; deep expiration, anterior margin of the shade.\nbe counted by the hand resting on that region as it can be on the male. The question of why women breathe costal, and men abdominal, we cannot pretend to answer. We doubt its being caused by any tight costume, for we found the same to exist in twenty-four girls between the ages of eleven and fourteen, none of whom had ever worn any tight dress. This peculiarity may be a reservation\nFig. 712.\nRespiratory Movements. Female.\nInspiration, dotted line. Ordinary, continuous line. Expiration, anterior margin.","page":1080},{"file":"p1081.txt","language":"en","ocr_en":"THORAX.\n1081\nagainst the period of gestation, when the abdomen cannot allow of so free a descent of the diaphragm.\nFig. 713.\nRespiratory Movements. Male. Front view.\nInspiration, broken line. Ordinaiy, continuous line. Expiration, dotted line.\nThe lateral movement of ordinary breathing is too limited to be represented by a line of varying thickness : the position is given by the continuous line, figs. 713. and 714.\nFig. 714.\nRespiratory Movements. Female. Front view.\nInspiration, broken line. Ordinary, continuous line. Expiration, dotted line.\n(b) Deep inspiratory. \u2014 In fig. 711. the dotted line shows this position, as when a man is just ready to displace his vital capacity-volume. The sternum is protruded and the abdomen is drawn in. This is the same in the female (fig. 712.), the dotted line is most advanced over the sternum, while over the abdomen it is drawn inwards.\nSo much is the abdomen drawn inwards by deep inspiration, that the portion of the continuous line (figs. 711, and 712.), representing theordinary breathing is (over the abdominal region) external to the dotted line of deep inspiration. Therefore the greatest\nenlargement of the thoracic cavity in both sexes is made by the ribs, and not by the diaphragm, as is generally believed. It appears very questionable whether the diaphragm is any thing more than flattened and that without descending.\nOf the position of the diaphragm. \u2014 It is clear that all that space between the line of ordinary breathing and deep inspiration (fig. 711.), below the ensiform cartilage, where the two lines cut each other, may be considered as just so much space deducted from the abdominal cavity ; and therefore the abdominal cavity, by deep breathing, is just so much less than it was in the position of ordinary breathing. Now, if the diaphragm descends at this moment, whilst the abdominal parietes are being constringed on all sides, what becomes of the abdominal viscera? We know that in ordinary breathing the abdomen advances because the diaphragm descends, and recedes because the diaphragm ascends. We may suppose the same accommodating movement between the diaphragm and abdominal parietes, to take place in deep breathing. There can be no doubt that the circumference of the thorax is increased, as shown \\WD.fig. 670., and that the diaphragm must extend its borders, and consequently the arch must be flattened ; but this may be without descending. We see (fig. 670.) that the section of the thorax to the area of the diaphragm is as 40 to 133\u2014the concavity of the diaphragm is enough to admit of its circumference expanding without its descending.\nFig. 715- is a diagram of sections of the base of the living chest in three stages, b is the chest in ordinary : a, as in extreme expiration ; c, as in extreme inspiration. In this case the vital capacity was 305 cubic inches, and the mobility of the chest was 5 inches, a range by no means common. The area of the chest varied 27 superficial inches between extreme inspiration and expiration.*\nIn the sitting posture the same relations\nSections of the hase of thorax in the three stages of respiration, in the living subject.\n* This is the chest offig. 711.","page":1081},{"file":"p1082.txt","language":"en","ocr_en":"1082\tTHORAX.\nexist in the breathing movements ; the only difference being that these movements are more limited.\n(c) Of the deep expiratory position. \u2014 In figs. 711. and 712. the margin of the shade is the position of the thoracic boundaries in deep expiration.\nWe have supposed the figures above mentioned as standing with the back fixed, for the purpose of making clearly manifest the relative position of these several breathing movements. In fig. 716. the body is quite free, and wholly alters its position in performing expiration and inspiration. This should always be considered in noticing the breathing movements in diagnosis.\nFig. 716.\nRespiratory Movements. Male, standing. Expiration, dotted line. Inspiration, continuous line.\n(d) Of the change of position by extreme breathing. \u2014 In expiration the head is protruded and loivered (see figs. 713. and 714.). Therefore, by inspiration the body is raised, and the more erect the more can be inspired ; by expiration it is lowered, so much so that we have seen men when displacing their vital capacity volume stoop themselves to one-half their natural height, to one-sixth frequently : we speak from a large number of cases,\u2014 nearly 4000. Physiologists have reasoned that, as upon the principle of a bladder becoming longer when empty than when inflated, so the chest is shorter when inflated than when empty. But this example in no way corresponds. The bladder expands, because it is inflated; the chest is inflated because it expands.\nWe have given the position of the breathing parts (the body fixed) : we shall describe\nthe movement of these parts relatively in time and order to each other, and the peculiar character of these movements in health, and some of their modifications by disease.\nOrdinary breathing.\u2014In men this is symmetrical, and very limited, and commences with an advancing and receding of the abdomen at and above the umbilical region, accompanied with a slight lateral enlargement, and immediately followed by a bulging outwards at the cartilages of the 7th, 8th, 9th, and 10th ribs, and that part of the abdomen contiguous to them, with a slight advance of the lower third of the sternum. This is abdominal breathing, because the abdomen moves first ; and is confined to motion of the base of the thorax. In women it is likewise symmetrical, commencing with a gentle heaving of the upper part of the thorax, more or less apparent according to the fulness of the mammae. This expansion commences with the 1st and next three ribs following each other in succession, accompanied with a slight elevation of the shoulders and a slight lateral enlargement of the chest, which is immediately followed by a bulging outwards of the abdomen. So quick is this motion of the diaphragm after the motion of the ribs, that at times they appear to be synchronous, especially when the individual examined is conscious of the observation, though it is only an accommodating movement of the diaphragm. This is costal breathing, because the ribs move first, and the motion is chiefly confined to the apex of the thorax. Therefore that which is a healthy respiratory movement in wpmen is pathological in men.\nOf the extraordinary breathing in both sexes (Inspiration). \u2014 This, like ordinary breathing, is symmetrical: the clavicles, shoulders, scapula, and superior ribs are raised, the sternum advances, the infra-clavicular region swells remarkably upwards and outwards (particularly in females) like a rolling wave, the supra-cla-vicular region is raised but this sometimes appears comparatively deepened (merely by the action of the sterno-cleido-mastoideus), the whole apex of the thorax is rendered more obtuse, particularly in the antero-posterior diameter. The lower ribs, at their cartilaginous extremities, spread outwards, increasing both the lateral and the antero-posterior diameter of the base of the thorax, the cartilaginous (gothic) arch formed by the junction of the 6th, 7t,h. 8th, 9th, and 10th ribs below the sternum, becomes more obtuse by their lateral motion, the abdominal space within this arch, down to the umbilicus, sinks inwards. Therefore this breathing is costal, commencing with the superior ribs, and terminating over the abdomen. The peculiar character of healthy breathing (and it is impossible to lay too much stress upon the movements of deep inspiration, because they are so indicative of thoracic disease) is that the ribs expand in succession. There is an indescribable undulating roll, produced by the consecutive action of the respective ribs, which always commences with a superior rib ; \u2014 in costal breathing, a lower","page":1082},{"file":"p1083.txt","language":"en","ocr_en":"THORAX.\n1083\nrib never moves first. In fact when we inspire deeply we feel as if we directed all our power to the four or five superior ribs, giving the greatest expansion to the very apex of the lungs, \u2014 that most vulnerable part in phthisis pulmonalis. When we look at the thoracic cavity we see why this great power and mobility is given to the upper part of the chest. We see that the six superior ribs encompass more space than the six inferior ribs. (See fig. 668.) So that where we command most movement, there is the greatest portion of lung to be expanded. The hand can measure most delicately this healthy characteristic swelling or filling up of the apex better than any instrument, because the hand covers alarge field ofthe chest, and can distinguish the undulating movement. Standing behind the person to be examined, the fingers of both hands should be placed over the clavicles, so that the tips rest on the infra-clavicular regions, and the thumbs over the inner borders of the scapulae. When a deep inspiration is taken the fingers and thumb of each hand diverge from each other, and we thus gain a perfect knowledge of the healthy \u201cswelling expansion.\u201d If the deep respiratory movement is good, the ordinary movement is sure to be good likewise. The mere flat hand on the anterior and upper part of the chest (facing the patient) will likewise give the character, though less delicately. This movement or swelling of the apex by deep inspiration, is more distinctly marked on the female than on the male subject. If this fine swelling motion in deep breathing is absent disease is present.\nPathological respiratory movements. \u2014 We now speak of another class of breathing movements, which are peculiar in this respect, that the \u201cundulating swell\u201d of the chest is wanting. The twelve intercostal muscles move in every combination, as if to meet impending difficulties, \u2014 tenacious of life, and yielding only by compulsion to the advance of disease. Throughout the long list of diseases which attack man these instinctive movements have to contend, \u2014 shifting about, or growing less and less. We have noticed a man with lung disease, commence with costal respiration of the lower ribs, and, as disease advanced, he breathed with ribs higher and higher up, so that at last he said, \u201c I breathe with my neck;\u201d and in truth it appeared so. His 1st, 2nd, and 3rd ribs only appeared to move. He passed through almost every variety of respiration before he died.\nThe breathing movements are quick to change, and the inquiry is interesting, what causes the change ? One great cause is the existence of dyspnoea, a disproportion between the air passages and the volume of air to be displaced, which may be caused by an obliterated state of lung, by tubercles, fluid in the pleur\u00e6, hypertrophy of the heart, aneurism of the great blood vessels, tumours of various kinds, the pain of local inflammation, pressure from the abdomen, whether ascites, obesity, distended stomach, gravid uterus, or any morbid growth bordering on the thoracic\ncavity, or lesion of nervous integrity \"requisite for maintaining the respiratory movements.\nSuch conditions of themselves would occasion deranged breathing movements. But again there are reasons for thinking that these movements may be changed from other causes not so purely physical ; because sometimes no dyspnoea is to be perceived, and yet the movements are deranged, or they may change backwards and forwards as if aerating specific portions of the lungs, acting as a curative remedy to some incipient form of lung disease. In complicated diseases of the chest a knowledge of the breathing movements is highly useful. There is one condition in the respiratory act, which is indicative of a certain state of chest, which, if not useful as a positive, is at least so as a negative evidence of some existing state of things in the lungs.\nThe condition we allude to is a sinking in and bulging out of portions of integuments which cover the thoracic cavity. If we close both nostrils and make a violent inspiratory effort, the integuments between the sterno-cleido-mastoidei immediately above the sternum, will be seen to sink inward from atmospheric pressure. If we open one nostril, the same is less apparent. If both are open and the passages are free, it is not perceptible. In expiration (with the same obstruction) there is a bulging outwards of these integuments. Sometimes, particularly in thin persons, this may be seen on the integuments covering the intercostal spaces. This sinking inwards is an evidence of attenuated air, and the bulging outwards of condensed air in the lungs, near to the part. It is therefore an evidence of some obstruction in the air passage.\nDifficult breathing may be attended with this feature, or not ; therefore it is an evidence of something existing in one state of dyspnoea which does not exist in another.\nDyspnoea without this \u201c sinking or bulging\u201d is a proof that there is no obstruction between the air cells and the external air. But, on the contrary, dyspnoea with this \u201c sinking and bulging,\u201d is a proof that there exists some obstruction either as a direct diminution in caliber of the air tube, or that more air is drawn through certain tubes than is natural; that this obstruction must have air on both sides of it, and that the air on one side is more attenuated than on the other. For instance, when an aneurism on one of the large vessels of a well-developed chest is pressing upon one of the large bronchi, the respiratory sounds, and those elicited by percussion, may be good, but respiration becomes laboured,\u2014 the case is obscure, but if there is alternate sinking and fulness of the lower part of the throat, we may be sure that there is some definite obstruction in the air passages. This, in connection with the history of the case, may lead to the detection of the cause and seat of the disease ; but dyspnoea without this feature could not be caused by an aneurism or tumour.\nIn emphysema of the lung this sinking and bulging is very manifest. This circumstance","page":1083},{"file":"p1084.txt","language":"en","ocr_en":"THORAX.\n1084;\nproves simply that there is air in the chest of different density to the external air ; and if so, there must be some impediment in the air tubes, preventing the restoration of atmospheric equilibrium.\nDisease of the thoracic viscera affects the breathing movements, causing them to be more limited, or non-symmetrical, reversed, massive, interrupted, partial, quick, slow, irregular, or double.\n(a)\tOf limited breathing movement. \u2014 The mobility of parts when disease attacks the chest may be surprisingly drawn forth. Haller allows scarcely any mobility to the first rib; Magendie asserts that the lower ribs are immovable, because they either reasoned from the healthy body, or anatomically : but it is not uncommon in phthisical patients to see strong and well-marked respiration kept up by the 1st, 2nd, and 3rd ribs, or by the 10th, 11th and 12th ; \u2014 these ribs are movable, but it requires disease to bring their mobility forth. We are satisfied that there is a latent respiratory mobility during health, which is manifested only by disease.\nIn disease particular parts take up exaggerated movements, but the sum of these movements is more limited than in health. In the earliest cognisable stage of phthisis pulmonalis the expansion of the thoracic apex is diminished ; the shoulders incline forwards and inwards, and become rounded ; the spine is less erect ; the apex cannot expand. The mobility of the inferior ribs does not so diminish, but sometimes maintains life to the last. With an exaggerated movement, the respiration is frequently costal and abdominal at the same time, as if no part could afford to be unemployed.\nIn 233 cases of phthisis pulmonalis (males) in the first stage we noticed that the breathing of 46 was costal, of 96 abdominal, and of 91 costal and abdominal. The mobility by tape measure was, instead of 3 inches and upwards, as follows; \u2014\nTable FF.\u2014 Diminished Mobility over the Nipples on 233 Phthisical Males.\nDifference between Inspiration and Expiration. \u00e8in- -\t\tNumber of cases. 3\n3\t_\t5\n4- 1\t_\t54\nH\t\t13\nH\t_\t44\nH\t-\t23\n2\t-\t53\n2*\t-\t12\n2*\t-\t25\n2f\t\u25a0\t1\n(b)\tOf non-symmetrical breathing move-ments. \u2014 In advanced stages of phthisis pulmonalis non-symmetrical movements are noticed ; but this may exist without a cavity or effusion of fluid in the lung; or a cavity may exist with symmetrical movements (but a cavity never exists without extensive dimi-\nnution of mobility). Genei'ally a cavity is attended with non-symmetrical movements, or a dragging up of one side of the chest ; and in extreme cases there is no movement at all in the region of the cavity. That symmetrical movements may coexist with extensive disorganisation or solidification of one lung is contrary to the opinion of many persons. It may be explained by the fact of our having so much spare lung. It has been found by experiment that 310 cubic inches of air could be forced into the lungs taken from a man with a healthy chest (height, 5 feet 4 inches ; weight, 107 lbs. ; vital capacity, 198 cubic inches), the absolute capacity of whose thorax at death, was 245 cubic inches : therefore there was spare lung for more than 100 cubic inches \u2014 a space which he could not command during life. May it not be possible that when a part of the lung is consolidated or disabled, this spare portion may come more completely into use, and allow of the symmetrical movement ?\n(c)\tOf reversed breathing movements. \u2014 A man\u2019s breathing may be costal or abdominal for a month, a week, a day, an hour, a minute, and change again, \u2014 every possible alternation may occur. This may take place with or without a cavity in the lungs, with or without phthisis pulmonalis, as if a specific motion drew in air to certain parts of the lungs to excite some local change of condition. Although costal respiration is maintained at a greater expense of vital force, yet we see when the vital power is fast ebbing the respiration is always costal, and the last breath is a deep costal inspiration followed by the last expiration.\n(d)\tOf massive breathing movements. \u2014 Massive breathing is a marked feature of the presence of emphysema in the lungs. There is a total absence of that undulating, rolling, and consecutive motion of the ribs. The breathing is always costal, though it may be conjoined with abdominal breathing, and the ribs are elevated in the mass, sometimes together with the shoulders clavicle and scapula. Massive costal breathing is indicative of emphysema of the lungs or pneumothorax. In all other forms of dyspnoea the undulating movement is more or less present, though limited.\n(e)\tOf interrupted breathing movements. \u2014 In those diseases termed \u201c nervousparticularly in young women, the breathing, especially the expiration, is sometimes interrupted and jerking. This appears to be merely a functional derangement ; it may sound to the ear like deficient respiration, for the intensity of the \u201c murmur\u201d is generally diminished, as if the jerking \u201ceased away\u201d the expiring air. This is sometimes the case in men. It is very seldom combined with organic disease of the lungs.\n(f)\tOf partial breathing movements. \u2014 By this we mean independent movement of certain ribs, or of some two or three of the respiratory regions. All the ribs may move as in emphysematous breathing, or none of them may move, or the lower, the upper, or the","page":1084},{"file":"p1085.txt","language":"en","ocr_en":"THORAX.\n1085\nintermediate set may maintain the respiratory function.\nAndral observes, \u201c The partial immobility of the ribs is not without interest in a physiological point of view. Does not this fact prove that, in inspiration, the ribs can move independently of each other, and that they have not merely a common movement ? If,\u201d says he, \u201c as we have often seen in phthisical patients, the lower ribs can still move when the upper ones remain motionless, it proves that independently of the action of the scaleni, the intercostal muscles are capable of taking, an active part in the act of respiration.\u201d* In this way respiration may be separately carried on by any of the twelve costal regions. We have seen a man ill of rheumatism, lying on his back, breathe solely with the diaphragm, and not present the slightest motion of any one of the ribs. And we have seen the contrary, viz., costal breathing, without the slightest movement of the diaphragm. They can act quite independently of each other. ;\n(g)\tOf quick and slow breathing movements. \u2014 Not only thoracic disease, but most illnesses, particularly febrile conditions, quicken the respiration. In health the number of respirations average twenty per minute (Table G G), and it has been found that in 244 phthisical cases (males), the average number was from twenty-four to twenty-eight per minute (sitting) (Table 11), the highest number was forty-four per minute. There is every reason to believe that the chemical quality of expired air is the same whether we are in health or in advanced disease, though our requirements at these two times may be very different; just as the quality of smoke from a fire is the same whether it burns briskly or slowly. \u2014 The quality is constant, and the required modifications are obtained by the difference of quantity in a given time. Quick breathing is short, and slow breathing is long, respiration. The natural time of breathing may change by habit. We have seen a man in health, whose ordinary respirations were six per minute. This extraordinary slowness was induced by an attack of asthma, during which attack (lasting about six years), his character of breathing changed from eighteen short, to six long and deep, respirations per minute ; though the asthma entirely left him the character of the respiration remained as first changed by the dyspnoea. In this case the return of eighteen respirations per minute, would be to him the rapid respiration of fever, although formerly the respiration of health. Time and volume, in respiration, are the great modifiers of the energy of aeration.\n(h)\tIrregular breathing. \u2014 Irregular breathing movements are less common when organic disease is present. A nervous person, as well as a phthisical person, may have every form of irregular breathing, but in the phthisical person the change is less frequent, and is probably due to some change in the disease ; in the\n* Andral, Clinique M\u00e9dicale, tom. iv. 3d ed. 8vo. Paris, 1804.\nnervous person the change is frequent, sometimes once or twice during an examination of the chest, Nervous breathing is generally well marked in hysteria.\n(i)\tDouble breathing.\u2014By this is meant cos tal and diaphragmatic breathing synchronous with each other ; this is not uncommon in severe cases of emphysema, when the mobility of the ribs is much diminished. It is frequently met with in phthisis pulmonalis; \u2014 in ninety-one cases out of 233. We have no voluntary power to command this form of breathing in health. It is to be looked upon as a serious modification of respiration. All the modifications of the respiratory movements, induced by disease, may return to healthy breathing again, if the derangement has not been kept up too long. As a general rule, the respiratory movements become natural soon after restoration of the diseased parts to health.\nOf the number of respirations in a given time. \u2014 The ordinary respirations should be counted without the individual being conscious of the observation ; otherwise they become disturbed in number, and sometimes in character.\nTable GG.\u2014Number of Respirations per Minute (sitting) in 1897 males.\nRespirations per minute. From 9 to 16\t\t\t\tNumber of cases. 79\t\n16\t-\t-\t-\t_\t239\n17\t-\t-\t-\t-\t105\n18\t-\t-\t-\t-\t195\n19\t-\t-\t-\t-\t74\n20\t-\t-\t-\t-\t561\n21\t-\t-\t-\t-\t129\n22\t-\t-\t-\t-\t143\n23\t-\t-\t_\t-\t42\n24\t-\t-\t-\t-\t243\n24 to 40\t\t-\t-\t-\t87\nOut of 1897 cases, 1731 of them breathed from sixteen to twenty-four times, and nearly one-third of them twenty times a minute.\nThe mean relative velocity of the breathing and the pulse is about one respiration to four pulsations of the heart (twenty to eighty), and the variation in health in the number of respirations is from sixteen to twenty-four, and of the pulse from sixty-four to eighty-eight per minute.\nTable H H.\u2014Relation between the Respiration and the Pulse (sitting) 1407 males.\nNumber of Respirations per Minute.\tPulse.\tNumber of Cases.\n16 -\t64 -\t- 218\n17 -\t82 -\t- 102\n18 -\t70 -\t-\t176\n20 -\t82 -\t- 546\n22 -\t83 -\t-\t135\n24 -\t88 -\t-\t230\nFrom Table 11, phthisis pulmonalis increases the velocity of the breathing movements from twenty (the healthy mean) to twenty-eight, and cases are numerous up to thirty-six respirations per minute.","page":1085},{"file":"p1086.txt","language":"en","ocr_en":"1086\nTHORAX.\nTable TI. \u2014 Number of Respirations, of 255 Phthisical Patients, per Minute (sitting).\nRespirations per\tNumber of\nMinute.\tCases.\n12 to 14\t\t_\t41\tL 4.1\t\n14 \u201e 16\t-\t-\toj\tr 4I\t1\n16 \u201e 18\t-\t-\t131\ti \u00bb!\tr 2i\n18 \u201e 20\t-\t-\t4 J\t\tl\n20 \u201e 22\t-\t-\t441\t\u25a0\t1\n22 \u201e 24\t-\t-\t11 J\t\t\n24 \u201e 26\t-\t-\t491\t[ 55 J\tr no\n26 \u201e 28\t\t-\t6J\t\ti\n28 \u201e 30\t-\t-\t471\t1 481\t\n30 \u201e 32\t-\t-\t1J\t\t1\n32 \u201e 34\t-\t-\t391\t\\ 4SJ\t[ 90\n34 \u201e 36\t-\t-\t3J\t\t\\\n36 \u201e 38\t-\t-\t16 1\tj. 17]\t|\n38 \u201e 40\t-\t-\t1J\t\t\n40 \u201e 42\t-\t_\t11\t[- 17J\t[ 34\n42 \u201e 44\t-\t_\t17J\t\t1\n\t\t\t*\t\t\nA sudden change in atmospheric pressure affects the number of breathing movements in a given time. We found the following limited but sudden increase of atmospheric pressure increase them as follows. In South-Hetton coal-mine in the county of Durham, \u2014 Depth of the mine 1488 feet.\nAt the level of the sea\tBarom. 28-72\tThermom. - -\t39\u00b0\nAt the bottom of the mine\t30-26\t- - 49\u00b0\nDifference\t1-54\t10\u00b0\nThe additional pressure of the\tan\natmosphere increased the ordinary breathing from one to three times per minute.\nThis difference was purely the effect of pressure, and not that of fatigue or mental emotion. It might only be temporary. Aeronauts inform us that diminished pres-\nTable KK. \u2014 Effect of increased Atmospheric Pressure on the \u201c ordinary \u201d Respirations upon six healthy men.\n\tON THE\tSURFACE.\tIN THE MINE.\t\n\tPulse.\tRespira tions.\tPulse.\tRespira- tions.\nM. P.\t56\t15\t50\t16\n\u2014 S.\t98\t20\t98\t24\n\u2014 H.\t72\t16\t68\t19\n\u2014 L.\t90\t14\t88\t15\n\u2014 W.\t88\t18 5\t93\t22\n\u2014 T.\t85\t18\t100\t20\nMean -\t83\t16-9\t84 3\t19-3\nsure increases the number of respirations ; but with them there is this difference, that with diminished pressure there is a sensation of a want of air. When the barometer is low we feel lassitude, and call the \u201c day heavy,\u201d when in truth the air is lighter, and we ourselves are heavier ; when the barometer is high, we generally experience an indescribable sensation\nof pleasure\u2014the vital energies seem doubled. With a sudden and considerable fall of the barometer there is a transient plethora. The blood-vessels become distended, owing to which, together with certain hygrom\u00e9trie changes in the air, we feel listless, and the least exertion produces perspiration. Duhamel observed that, in the month of December, 1747, the barometer in less than two days fell in., producing a change of pressure on the body of a man, of 1400 lbs. ; this he observes was accompanied with many sudden deaths. It is evident that with an increased pressure we get more air into the lungs with a given mobility; for, c\u0153terisparibus,air,with the barometer at 30 in. must be more dense than the same air with the barometer at 29 in. In the mine in question, we experienced a sensation of lightness and vigour. The number of respirations are always increased when there is a preternatural increase in the temperature of the body.\nOf the Sounds of Respiration. \u2014 The breaking up of the air into minute streams was discovered by Laennec to produce certain sounds, named \u201cbreathing sounds:\u201d which sounds are now made available in detecting organic disease in the lungs. As the air penetrates the lungs, it is divided and subdivided until it enters the minute air vesicles. The air passes, 1st, through the trachea, producing \u201c tracheal sounds,\u201d \u2014 a hollow rough blowing ; 2nd, through the next division of vessels (bronchial), producing \u201c bronchial sounds,\u201d less hollow and termed \u201c whiffing or tubular ;\u201d and, 3rd, into the air vesicles, producing \u201c vesicular sound,\u201d \u2014a soft, silky murmur like a gentle breeze among the leaves of trees. Dr. Jackson discovered that which Laennec overlooked : \u2014 this murmur is not heard in expiration, while the other two sounds are. Hence the expiratory murmur is a morbid sign, and if heard on the left side below the acromial end of the clavicle, is a sure sign of some altered condition of the air tubes, not compatible with a healthy lung. This expiratory murmur may sometimes be heard faintly on the right side, and not be a morbid sound ; but if strongly heard there, it is a morbid sign. A question now arises : Why is there a murmuring sound with inspiration and not with expiration ? First, let us inquire what is the difference between the inspiratory and the expiratory act ? They differ in two ways :\n1st. In Inspiration the lungs are passive ; the chest threatens a vacuum, and the air enters a rarefied space. In Expiration the lungs are active ; there is no rarefied space ; the air is squeezed out into the atmosphere. This does not affect our question.\n2dly. In Inspiration a volume of air is broken up into smaller and smaller streams. In Expiration these small streams are collected up into the original volume by larger and larger streams. This answers the question.\nThe hollow blowing sound in the trachea is caused by the friction of the air against the sides of the tube. The relation of the friction","page":1086},{"file":"p1087.txt","language":"en","ocr_en":"THORAX.\nto the stream is the same whether the air passes into or out of the lungs, therefore the tracheal sounds are equally heard in expiration and in inspiration. But not so in the lungs ; here, as the stream of air proceeds it is subdivided, and with every subdivision the friction is increased ; so that with every advance of the stream into the substance of the lung the sound is increased, and becoming more and more buried in the substance of the lung is heard as in a continual murmur. In expiration the very contrary happens. The friction is as quickly diminished, until the substance of the lung entirely masks what remains. In the larger vessels when the volume of the returning air becomes great, and the diameter of the tube more uniform, the friction is the same whichever way the air passes, and here tracheal and bronchial expiration are audible, during inspiration as well as expiration. If we take a sheep\u2019s lung and inflate it, we hear the inspiratory murmur ; let go the air and we do not hear it ; but contract part of the lung, say with the edge of a paper knife, and you hear the mur-\nI.\tIn its Intensity\n1087\nmur during the lung\u2019s collapsing, showing that by increasing the friction you produce the expiratory murmur.\nWhen any disease thickens or diminishes the diameter of the air tubes, or when one part of the lung is obliterated and another part has to do double work, then the friction is increased, and thus expiratory murmur is a true sign of some change in the minute air tubes of the lungs. Sometimes the breathing murmur is so gentle and the thickness of the muscles so great that we have even in health known the inspiratory murmur quite inaudible.\nIn organic change of the lung these sounds become changed in their intensity, rhythm, and character. The cause of the change of sound is yet involved in much obscurity ; hence some persons have been said to have had tubercular lungs, when such has not been the case ; or even extensive cavities, &c., yet.time has shown that there never had been cavities. All the morbid, true sounds yet require to be verified as to their cause. As we have natural changes in the character of breathing, so are there changes in the sounds of breathing, as follows : \u2014\nStrong or exaggerated. Feeble.\nAbsent or suppressed, f Quick.\n\\ Slow.\nJerking or interrupted. Long.\nShort.\nExpiration prolonged, f Harsh.\nJ Bronchial or tubular.\n\"I Cavernous.\nAmphoric.\nII.\tIn its Rhythm\n1. Frequency\n2. Duration\nIII.\tTn its Character\nWhen there is fluid or disorganisation in the substance of the lung, there are certain cracklings, crepitations, and gurglings, causing certain other sounds not included in the above list. Unfortunately authors differ in the application of the names for these sounds. They may be all classed under two heads, the dry and the moist, whether the tubes be large or small in which the sounds are produced.\nFor the Bibliography see that of art. \u201c Resfiration,\u201d p. 366.\n(J. Hutchinson.')\nTHYMUS GLAND.\u2014(French,Be thymus; Italian, Timo; German, Die Brustdruse; Lat., Thymus; Greek, Qvyoc. )\u2014 It is proposed in this article to adopt the following arrangement : First, to treat of the gland as it exists in the human subject, comprehending its ordinary and structural anatomy, and its development. Secondly, to give a sketch of the cpmparative anatomical history of the organ. Thirdly, to treat of its physiology. Fourthly, to mention what has been observed of morbid changes occurring in it.\nHuman Anatomy. \u2014 Sir A. Cooper\u2019s description of the gland in the human subject is as\nfollows:\u2014\u201cThis gland is formed of a thoracic and cervical portion on each side. The former is situated in the anterior mediastinum, and the latter is placed in the neck, just above the first bone of the sternum, and behind the sterno-hyoidei and sterno-thyroidei muscles.\u201d \u201c Between two and three months of foetal life, as will be seen in the plate (fig. 717.), it is so\nFig. 717.\nThe thymus, heart, larynx, \u00a7*c., of the human f\u0153tus at rather more than two months. (After Sir A. Cooper.)\nsmall as to be but just perceptible. At three months (fig. 718.) its increase is in proportion to the relative magnitude of the foetus, and thus it continues to grow gradually and equally (fig. 719.) to the seventh month, when it enlarges out of proportion to its former grovvth. At eight months it is large, but at the ninth","page":1087},{"file":"p1088.txt","language":"en","ocr_en":"1088\nTHYMUS GLAND.\nFig. 718.\nThymus, \u00a7T., of human f\u0153tus at third month. {After Sir A. Cooper.')\nmonth (fig. 720.) has undergone a sudden change, becomes of great size, and is said to weigh half an ounce, from which circumstance, however, on account of the cavities which it\nFig. 719.\nThymus, fyc., of human f\u0153tus at fifth month. {After Sir A. Cooper.)\ncontains, and the varieties to which it is subject, no judgment of its bulk can be formed. It increases after birth, and continues large to the first year, when it slowly disappears to the time of puberty ; and in after age it ceases to have cavities, and becomes a body of very small dimensions.\u201d\t. .\nHe next notices the following varieties in configuration \u201c Although the gland is usually double, and the one side united to the other by cellular membrane only, yet it sometimes happens that a third thoracic lobe exists, which appears to join one lobe with the other, but which allows, under a careful dissection, of their being separated. There are also two other varieties I have seen ; the first is the vena innominata passing through the gland, and the second, the same vein placed anteriorly to the cervical lobes. Indeed, I scarcely find two organs alike in form ; sometimes they are round, whilst others are of greaUength, and are so thin that the serpentine disposition of their lobes may be seen without dissection. The left gland is often larger than the right ; but even in this respect so much variety is observable, that it appears if the bulk of the\nFig. 720.\nThymus, fyc., of human f\u0153tus at ninth month. {After Sir A. Cooper.')\nwhole be the same, that it is of little importance which may be of the greater magnitude, the right or left gland, as its secretion will be equally abundant.\u201d\nThe relative situation of the thymus gland to the adjacent parts is described as follows : \u2014 \u201cIn cutting through the sternum in its long axis, and then separating its two lateral portions, so as to give a good view of the mediastinum, the thymus gland appears situated behind the first and part of the second bone of the sternum ; and posteriorly to the origins of the sterno-hyoidei and sterno-thy-roidei muscles. It reaches more than half way down the sternum at birth, viz. to the fourth rib, and extends from thence into the neck near to the thyroid gland. It is connected to the sternum and origins of the sterno-hyoidei and sterno-thyroidei muscles by cellular tissue ; it adheres strongly, by a coarse cellular membrane, to the pericardium; anteriorly and laterally the internal mammary arteries and veins take their course. The reflection of the pleura descending from the cartilages of the ribs on each side, and continued to the fore part of the pericardium forming the anterior mediastinum, makes its lateral boundaries, and separates it from the lungs; posteriorly it rests upon the vena innominata, and upon the fascia of the thorax, which descends from the sternum and first rib to the curvature of the aorta, and to the three large vessels which spring from it.\u201d \u201c Such, then, is the relative situation of the gland in the chest. In the dissection of the cervical","page":1088},{"file":"p1089.txt","language":"en","ocr_en":"THYMUS GLAND.\n1089\nportion of the thymus, the platysma myoides and external jugular vein are first turned aside, and the origins of the sterno-mastoidei muscles are raised; when this has been accomplished, the sterno-hyoidei appear covering and passing over the thymus gland. The sterno-thyroidei muscles . . . cover this organ anteriorly; but when they are removed, the cervical portions of the thymus are seen on the anterior and lateral parts of the trachea, and just below the thyroid gland, where it passes on the fascia on the fore part of the air tube, and unites with the larynx by ligament.\u201d\n\u201c The internal jugular veins are placed anteriorly and laterally to the cervical portion, and the carotid arteries, with the par vagum, appear more externally.\u201d\n\u201c The first bone of the sternum and sternal ends of the clavicle cover the junction of the cervical with the thoracic portion of this gland.\u201d\n\u201c In many of the subjects which I have examined, the cervical portion of the thymus passes higher upon the right than on the left side, and I have generally seen it joined by a ligament to the larynx, and by vessels to the thyroid gland.\u201d\nIn a human foetus, at about the fourth-and-a-half month, I found the thymus consisting of two lateral portions, of which the right was the larger (in another of similar age the left was) ; this portion extended downward, lying upon the pericardium, as far as opposite the\nFig.\nright auricular appendix, and reached upwards only to the left brachio-cephalic vein, which it did not cross ; the left extended downwards, over the pericardium, to a point opposite the middle of the trunk of the pulmonary artery, and passed up, lying upon the vena transversa, and afterwards upon the side of the trachea, between it and the common carotid, till it arrived at the level of the bifurcation of the arteria innominata.\nThe appearance of the gland in the foetus about the middle of utero-gestation is precisely similar to that of the salivary gland in the same ; it is beautifully lobulated, and surrounded by an atmosphere of nascent areolar tissue. In the more perfectly formed condition it is surrounded by an envelope of coarse cellular membrane, which penetrates the intervals of its larger divisions, unites the right and left portions together, and forms a general envelope, by which it is connected to the surrounding parts.\nIn examining the structure of the thymus, we are conducted by two eminent guides to conclusions almost identical, though by different modes of proceeding. This coincidence is of great value, and we can scarcely entertain a moment\u2019s doubt of its being founded on real truth ; it may therefore be well to notice separately the modes of investigation above referred to.\nSir A. Cooper, by skilful manipulation, succeeded in unravelling the gland, and showed each lateral part to be composed of a\n721.\nThe right and left thymus gland injected with wax and partially unravelled. In one are seen the rope, the lobes, and the cells, in the other the communication between the thoracic and cervical portions. (After Sir A. Cooper.)\n4 A","page":1089},{"file":"p1090.txt","language":"en","ocr_en":"1090\nTHYMUS GLAND.\nrope, on which the lobes and lobuli are set somewhat like the beads on the string of a necklace (fig. 721.). By injecting also the glandular cavities with some fluid, as alcohol, capable of hardening the tissue, or with coloured gelatine, which sets and permanently distends them, he demonstrated the existence of a central cavity or reservoir, communicating with the glandular cavities by orifices leading into pouches situated at the roots of the lobes (fig. 722.). The central cavity forms a\nSection of thymus showing the reservoir, cells, and pouches. (After Sir A. Cooper.')\ngeneral communication between the different lobes ; it does not maintain a straight course, but passes in a somewhat spiral manner, beginning from the low'er part of the thoracic portion, and extending even into the extremity of the cervical part of the gland : its size varies in different parts, being largest near the centre of the thoracic, and least at the communication of the thoracic with the cervical, part of the gland. Sir A. Cooper conceived the reservoirs to be lined by a very vascular mucous membrane of somewhat villous character, but this does not appear in reality to exist.\nSuch were the principal results obtained by a most skilful and eminent anatomist, with all the appliances and aids that his science could at that day supply ; they were truly valuable facts, but not so \u201c luciferous,\u201d not so exhibit-ant of physiological meaning, as those obtained by a subsequent inquirer, who, availing himself of the more penetrating ken of the modern achromatic lens, and seeking rather to learn from the instructive examples which Nature herself sets forth, than from results of his own devising and producing, has both confirmed the conclusions drawn from a less refined scrutiny, and invested them with a more correct bearing and interpretation. I refer, of course, to the admirable researches of Mr. Simon, which I now proceed to detail, respecting the structure of the thymus, as illustrated by its developement.\nDevelopement. \u2014 The first trace of the or-\ngan which has been discovered is in the form of an exceedingly delicate tube, lying along the carotid vessels in the neck, not straight, but wavy at one part, and terminating by closed extremities at both ends (fig. 723.). Its wall is formed by a transpa-\nFig. 723.\nPrimary tube. (After Simon.)\nrent homogeneous tunic, marked at regular intervals with elongated thickenings (the remnants probably of the nuclei of primordial cells), and enclosing granular matter, but no distinct corpuscles. There seems some probability that this tubular form, though found to prevail in very early embryos, may not be the really primitive one, but that a linear series of cells is first developed, which are afterwards blended together by fusion, so as to constitute a tube (seej\u00a3g.724.)j this opi-\nFig. 724.\nSupposed origin of primary tube. (After Simon.)\nnion however, I suspect, will not be confirmed ; the limitary membrane of glandular and other structures has generally appeared to me to be produced quite independently of cells, so far, at least, as that it should be regarded identical with their coalesced envelopes. In the next stage of developement, the homogenous wall of the tube begins to bulge, and swell out into vesicular cavities, which at first have wide communications with the central canal or tube, and are quite sessile, but afterwards become attached by short and rather narrow","page":1090},{"file":"p1091.txt","language":"en","ocr_en":"1091\nTHYMUS GLAND.\npedicles {figs. 725. and 726.). This budding Fig. 725.\nFig. 726.\no o \u00a9 \u00a9\n\u00a9 \u00a9 e\n\nSecond stage of developement of primary tube forming follicles. (After Simon.')\nout of the primary tube does not occur simultaneously at every part, or uniformly, but chiefly at those situations which are ultimately to attain the largest size ; thus in the foetal calf we find tolerably well developed bulgings of the primary tube opposite the angle of the jaw, the upper part of the trachea, and the pericardium, while the intervening\nportions have smooth and undulated margins ; and it is just the parts of the gland corresponding to the above points, which ultimately attain the greatest magnitude. The third stage of developement consists in the ramification of the follicles which have budded out from the central cavity; \u2014 they do not usually elongate much, before they throw off fresh offsets, and these are completely sessile, so that they have the appearance of vesicles or imperfect spheres grouped together : the mode in which the primary offset divides is either dichotomous or quaternary (figs. 727. and 728.), probably also often with some degree of irregularity and inequality in the size of contiguous offsets. By the extension\nFigs. 727, 728.\nThird stage of developement. Ramification of follicles by dichotomous and quaternary division. (After Simon.)\nof this follicular growth to all parts of the primary tube, and by successive lateral ramifications, occurring, as we have seen, to a greater extent in some parts than in others, the gland attains its mature size and complex structure. In this state however it consists, in very great measure, of vesicular cavities, which cluster around and completely obscure the primary tube from which they have originated ; yet this primary tube or reservoir does exist, and is capable, as we have seen, of being demonstrated, so that the term which Mr. Simon has proposed, as expressing the type of the mature structure, viz. tubulo-vescicular, is sufficiently correct (fig. 729.). Two varieties have been observed in the seeond stage of the process ; one is, that \u201c the tube sometimes bulges uniformly in its whole circumference for some extent, forming a very distinct ampulla;\u201d the other, \u201c that in parts where there are yet no bulgings, it is sometimes flexuous, or even contorted.\u201d\nThe observations now detailed respecting the progressive developement of the thymus, are so important in the elucidation of its structure, that I thought it very desirable to repeat them, if possible, and confirm their accuracy by independent testimony. I have not, however, been able to procure a foetus at a sufficiently early period to discover the primary tube of the thymus, with its smooth","page":1091},{"file":"p1092.txt","language":"en","ocr_en":"1092\nTHYMUS GLAND.\nFig. 730.\nFig. 729.\nDiagram, of fully developed thymus.\nShowing how the primary central tube is covered and concealed by the lateral developements, each of which constitutes a conical mass, a, b, c, d, with a very wide base. (After Simon.)\nunbulging wall, but I have seen it distinctly at a period somewhat later, when the process of lateral extension had but recently commenced. This was in the embryo of a sheep, not more than two inches long, where the thymic cavities were bounded by a well-marked limitary membrane, and filled with nuclei. At the extremity of the cervical portion, thedevelope-ment of bulging offsets was much less advanced than towards the middle of the gland, so that here the central tube was very apparent, terminating by a closed extremity, and having its margins rendered irregular and wavy by the vesicles which had begun to rise from it (flg. 730.). The developing organ was formed in a nidus of homogeneo-fibrous tissue, interspersed with nuclei, which was seen stretching across between the prominent convexities of the bulgings. At the end of the cervical portion this tissue was more abundant, and there was seen running into it a prolongation of the central cavity, which appeared exactly like a short tube, pushing on in a straight direction, and not expanding nto a vesicular cavity. In a young chicken the condition of the thymus was very similar, and the central cavity was larger than the small lateral offsets. These details, though incomplete, leave scarcely a shadow of doubt that Mr. Simon\u2019s account is perfectly correct, that the central cavity is the primary part from which the vesicular offsets successively develope themselves. This central cavity may, I am inclined to believe, in some cases disappear more or less completely ; at least, in an embryonic sheep, three inches long, it not only bore a smaller proportion to the multiplied offsets, but its wall no longer exhibited the investing limitary tissue, and it seemed as if it\nExtremity of cervical portion of thymus from embryonic sheep. 2\u20143 in. long.\nThe end of the tube is closed, the central cavity is larger, the walls present numerous follicular protrusions of irregular size and form. Towards the middle the follicles are very much more developed.\nwere in some measure diminishing, and losing its original distinctness. From what I have seen in the sheep, I should be led to think that the cervical and thoracic portions of the thymus had, in that animal at least, distinct primary tubes as centres of developement, so completely independent have the two parts seemed to be of each other.\nMature structure of the gland. \u2014 The results of minute scrutiny into the structure of the fully-developed thymus, accord well with those arrived at by other modes of inquiry. Its surface, when freed from investing areolar tissue, exhibits, though in a rather coarser manner, the minutely-divided appearance so characteristic of the conglomerate glands, and this is especially evident when fat cells have formed in the interstices of the lobules, patterning the surface over with a network of white streaks. In a thin section taken from the gland and prepared for the microscope, the outlines of the vesicular cavities are readily seen ; they are much larger than those of the salivary glands, and vary very much in size; in a human foetus, at about the midperiod, they averaged ^ inch, in a calf about jV 'nc\u2019lb in a young guinea-pig they varied from to Jg- inch. Their form is oval or spherical, their outline distinct for about two-thirds of their circumference, but in the remaining part blended with adjacent ones, so that there is never seen any thing resembling","page":1092},{"file":"p1093.txt","language":"en","ocr_en":"THYMUS\na detached and closed vesicle. The sharp definition of the outline by a clear dark line, gives full assurance of the presence of an investing limitary or basement membrane ; this constitutes a general envelope, forming the boundary of each of the glandular cavities, surrounding, therefore, the whole mass, but nowhere prolonged into an efferent canal, through which the contents might escape. In structure it is truly homogeneous, that is, considered per se, but as it is closely invested by a very thin layer of areolar tissue on its exterior, it has sometimes a kind of fibrous, striated, aspect. In all respects it closely resembles the basement tissue of other glands, and, as in them, I have never been able to perceive in it anything corresponding to the germinal centres of Mr. Goodsir.\nThe contents of the thymic cavities next demand our attention. They consist almost entirely of corpuscles, very closely resembling (in fact identical with) the nuclei of glandular cells ; the only difference which the most careful scrutiny can detect between them, I believe, is this, that they present more numerous nucleoli than the nuclei of gland cells usually do. I doubt, however, whether even this is constantly the case. Their form is, I think, for the most part spherical ; Mr. Simon speaks of them as generally flat and circular, but I have never observed one, if this be their real form, presenting its thin edge to the eye, as blood-discs frequently do. They vary a good deal as to the condition of their interior spots or nucleoli, some contain two or three, some as many as four or five, a few have one only, and some of the smaller none at all, but are filled with a dimly molecular substance. Their surrounding envelope is strong and well defined, as that of nuclei always is. The extreme variations in size of these corpuscles, according to Mr. Simon, are inch for the largest, and\tf\u00b0r the smallest, probably a\ncorrect average, for the generality is about inch. Mingled with these I have found in the thymus of a calf, as well as in that of a young guinea-pig, a few larger corpuscles, about double the size of the former, of spherical form, filled either with granular matter alone, or containing also a nucleus or larger vesicular body. I am by no means inclined to regard these as cells formed upon the originally-existing nuclei of the cavities, but rather as expansions of the nuclei themselves, with formation of granular matter in their interior.\nIt is well worthy of remark, that in the fully developed organ, before any appearance of atrophy has taken place, no other contents than those now described are found in the glandular cavities. There is none of the abundant granular material which forms so large a part of the epithelium of most glands, no diffused oily matter, the nuclei aggregated together into dense masses seem to fill tne ultimate vesicles completely, and there is no trace of any material which can justly be regarded as the product of secretion.* A\n* The contrast in this respect between the thy-\nGLAND.\t1093\nstrongYsolution of bichloride of mercury, indeed, coagulates a small quantity of diffused plasma (probably the liquor sanguinis of blood remaining in the capillaries) which adheres irregularly round the neuclei, but its effect on the contents of the thymus is very different from that which it has on the albuminoid epithelium of the true glands. This is a remarkable circumstance, and, as yet, has not, I think, been sufficiently attended to. If we endeavour to interpret it, it would seem to imply that the thymus is not truly a secreting organ, that is, that it does not separate from the blood or elaborate any special product, or in fact any product at all ; but that its function is limited to the formation of an apparatus, which conforming closely to the type of secretory glands is yet not endowed with any analogous property. * The centres around which the material of the secretion should be evolved are present in myriads, but no granular substance analogous to that of glandular epithelium is formed around them. It seems, therefore, that in the case of the thymus, the liquor sanguinis exuded from the vascular plexus through the homogeneous tunic simply solidifies into cytoblasts or nuclei, in most other glands a part takes the same organic form, \u2014a certain number of nuclei are formed,-\u2014 but these then become the centres of a different and more complete action, or are endued with peculiar attractive powers, in virtue of which the materials of the several secretions collect around them in their respective laboratories. Such is the fact microscopic inquiry adduces, and such the interpretation which may be offered of it; let us now turn to chemistry, and inquire whether the view we have just suggested is supported or negatived by the result of analysis. Mr. Simon gives three analyses of the thymus, which, as he states, though performed on the tissue itself, and not on its fluid contents, may fairly be depended an for conveying a sufficiently correct idea of the chemical constitution of the matters contained in its cavities. Now in none of these is there any mention of any special substance which could be regarded as characterizing the secretion, on the contrary, the constituent elements are mere fibrinous, albuminous, or extractive matters and ordinary saline compounds, and there is none of these which might not exist in the blood, and be most readily derived from it. This is, in fact, the conclusion which Mr. Simon adopts ; he believes that we may express the nature of the secretion of the thymus as nearly as may be by the formula of Proteine, or denominate it, in physiological language, as simply nutrient matter.\nmus and the thyroid is very instructive, in both the limitary membrane forms closed cavities, which in the one are chiefly filled with secretion, in the other with nuclei, the accredited agents of secretory action.\n* Whatever may be the nature of the fluid said to be contained in the thymic cavities in which the nuclei float, it is too small in quantity, and too little apparent, to make it necessary to take it into account ; certainly it never collects after the manner of a secretion.\n4 A 3","page":1093},{"file":"p1094.txt","language":"en","ocr_en":"1091\nTHYMUS GLAND.\nSir A. Cooper describes the vascular supply of the thymus as follows : \u2014 \u201c With respect to the arteries of this organ, they are principally derived from two sources. Each thoracic portion is supplied by a branch which is sent off by the internal mammary. It enters at the junction of the cervical with the thoracic part, generally on their outer side, but sometimes between the cervical portions, and, descending upon the middle of the gland, divides to supply the spirally disposed lobes. The other principal artery of the thymus is sometimes derived from the superior thyroi-deal, at others from the inferior thyroideal artery, and, descending upon the lobes of the cervical portion, passes into them, and ultimately anastomoses with the branch from the mammary artery. The thymic arteries may also arise from the trunk of the subclavian, the vertebral, or the carotid artery, or even from the arch of the aorta. The capillary network in which the arteries terminate, is stated by Mr. Simon to be of \u201c the completest description. It is so arranged as to include each individual vesicle within a vascular capsule ; the capillaries are closely applied upon the transparent texture (limitary membrane) which bounds the cavities, and so exceedingly dense is their network that the meshes are of even less diameter than the vessels themselves. Every portion of the glandular substance is thus exposed in the completest manner, and at every point of its surface, to the penetration of the fluid ingredients of the blood.\u201d \u201cThe venae thymic\u00e6\u201d Sir A. Cooper states \u201c have a different course to the arteries ; for although the internal mammary and thyroideal veins receive small branches from the gland, yet the principal veins are those which end in the vena innominata. A considerable vein springs from each thoracic portion, and passes from the posterior surface of this part of the thymus into the vena innominata; having received a branch from the cervical portion, and vessels from the thoracic: it is found near the centre of the gland. A very small vein enters the thyroideal from the cervical portion, and this vein anastomoses with that of the thoracic part.\u201d\nRespecting the absorbent vessels of the thymus very little seems to be known ; we may, however, fairly conclude from the analogy of other parts, that they commence by a network of minute vessels, which have no communication whatever with the glandular cavities, and cannot, therefore, serve the purpose of excretory ducts as has been supposed : the glands to which they proceed are those of the anterior mediastinum.\nMr. Simon describes the nervous supply of the thymus \u201c as mainly derived from the plexus which surrounds the first part of the subclavian artery, and which has its chief origin from the inferior and middle cervical ganglia. A small twig detaches itself from this sympathetic plexus, just opposite the origin of the internal mammary artery, accompanies that vessel in its course, and, on arriving at the point where the thymic branch\narises, sends filaments along it into the substance of the gland. A second source of supply is the cardiac branch of the pneumogas-tric, which gives on each side a minute filament to the superior part of the gland.\u201d \u201c In one instance I have seen a very minute fibril of the descendens noni emerge from the substance of the sterno-thyroid muscle, and reach the cellular investment of the thymus ; and I have sometimes seen delicate twigs of the phrenic also detached towards the gland ; but in each case the nerve has appeared to restrict its distribution to the surface and coverings of the organ, and has not accompanied any of its vessels.\u201d\nThe exact arrangement of the nervous fibrils, both tubular and sympathetic, in the substance of the gland is yet unknown ; but it seems tolerably certain that they accompany the vessels, enlace them with their plexiform divisions, and terminate, in part at least, in a looping manner.\nEarly development. \u2014 The following quotation from Professor Goodsir\u2019s paper in the Philos. Transactions, contains his views re specting the development of the thymus and two others of the ductless glands ; I am unable from my own observation to confirm or dispute the accuracy of his opinion, but cannot do otherwise than refer to the labours of so distinguished a physiologist.\n\u201c That portion of the membrana intermedia which is separated from the rest of the membrane, and included in the body of the embryo by the umbilical constriction, and which has not already been devoted to the formation of the heart, liver, pancreas, and external portion of the intestinal canal, is found massed along the trunks of the primitive venous system, the sides of the arches of the aorta, the terminal portion of that vessel, and the origins of the omphalo-mesenteric arteries. The portions of the membrana intermedia which are last in being converted into special organs, the Wolffian bodies, are the parts which project one on each side of the aorta along the posterior part of the cardinal veins of Rathke, between the intestinal plates and visceral laminae. The portions of the membrana intermedia, which remain between the upper extremities of the Wolffian bodies and the heart and liver, and which surround the origins of the omphalomesenteric arteries, do not become converted into organs of special structure, but retain during life the original constitution of the membrana intermedia of the blastoderma, and increase rapidly in the embryo constituting the supra-renal capsules. That portion of the membrana intermedia which is situated between those two aortic arches the extremities of which become the carotid and subclavian arteries, remains during life as the thyroid body. It receives its blood from the first and second aortic arches by two large trunks on each side, the superior and inferior thyroid arteries. That portion of the membrane which passes in two parts from near the base of the cranium back as far as the ductus Cuvieri and anterior portions of the veins of Rathke, and","page":1094},{"file":"p1095.txt","language":"en","ocr_en":"THYMUS\nwhich are united and concentrated in front of the heart, by passing from behind forwards in harmony with corresponding motions of the neighbouring part, becomes the thymus. The structure of these organs is identical with that of the blastoderma (?). Their probable function, namely, to prepare by the action of their nucleated cells, and to throw into the vascular system a matter necessary for the nutrition of the animal during the period of its active growth, a function which the observations and opinions of the majority of physiologists have assigned to them, is also essentially the same with that of the blastoderma.\u201d\nDevelopment of Size.\u2014Having now examined the anatomy of the thymus, and traced its development with a view to the exact elucidation of its structure, we have next to follow out the successive periods of its growth, in order to determine whether it be an organ having special relation to foetal or to extra-uterine life. The former alternative was that to which the older anatomists, and even Sir Astley Cooper, inclined ; but the correctness of the latter seems now abundantly established. Meckel, Hewson, Cloquet, and Sir A. Cooper himself, all concur in stating that it continues to grow at least up to the end of the first year after birth ; and more recently the evidence accumulated by Mr. Simon from his own observations and those of Hangsted have quite set this important point at rest.\nThe following details have been selected from the copious table of instances contained in Mr. Simon\u2019s essay, they show conclusively that the gland does not attain its greatest size for some time after birth, and that after a variable period it gradually again diminishes. Thus in the dog, at birth the gland weighs 4\u201975 grs. ; from 3^ months to year after it; varies from 360 to 780 grs. ; from 3 to 4 years it varies from 150 to 46 grs. In the cat, at birth its weight=6|- grs. ; from 19 to37 days after it\u2014 30 to 44grs. ; 4 to 6 years after=20 to 3 grs. In the human f\u0153tus of 7 months the gland weighed 33 grs. ; at 8 months 40 grs. ; at birth 84 to 240 grs.; 9 months after, 270 grs.; at 21 years 40 grs. The weight of the thymus is subject to considerable varieties, which probably depend, as Mr. Simon points out, partly on original differences, some individuals haying naturally a larger proportion of thymic structure than others ; partly also on temporary alterations in the activity of the nutrient processes, as is well exhibited in the effect of over-exertion on the thymus of lambs remarked by Mr. Gulliver ; the size of the gland is known also to diminish when the development of the muscular system is promoted, it being found to waste away much more rapidly in young oxen used for draught, than in others not so employed.\nThe general conclusion, which the able physiologist from whose work I have drawn so largely adopts, is, I think, truly judicious and accurate ; he estimates the period, during which the thymus persists and is active, not so much according to the space of time which has elapsed, but according to the state of the\nGLAND.\t1095\ngeneral functions of the frame : if the assimilating processes are active and vigorous, and the supply abundant, and the demand only moderate, the gland will be large and will persist long ; if on the contrary the first processes of nutrition are imperfectly supplied, or if great muscular exertion creates a considerable demand, then the thymus ceases earlier to discharge its function and becomes atrophied, because the conditions no longer exist which are favourable to its subsistence. Now it is obvious that in almost every individual these circumstances which so greatly affect the nutrition of the thymus may vary exceedingly, and it is therefore impossible to state an exact numerical age as the period of the highest development of the gland ; a physiological age may however with much certainty be named, and it is, as Mr. Simon states, \u201cthe age ofearly growth.\" The date of the earliest appearance of the thymus in the human f\u0153tus is still little more than matter of conjecture, it. has not been positively detected before about the 9th week, when it is quite distinct to the naked eye, consisting of two lateral elongated portions lying parallel to each other on the upper part of the pericardium. Its structure at this time is distinctly tubulo-vesicular, but. there is doubtless an earlier stage, when it corresponds exactly to the simple primary tube discovered, as before mentioned, in very early mammalian embryos. The epoch of its entirely vanishing is very variable and uncertain \u201c about puberty it seems in most cases to suffer its chief loss of substance, and to be reduced to a vestigiary form but for several years later, even up to 20 or 25, distinct remnants may still be discovered of its structure amid the areolar tissue of the mediastinum.\nComparative Anatomy.\u2014In presenting a sketch of the comparative anatomy of the thymus, I can but follow the elaborate account given by Mr. Simon.\nMammalia. \u2014 Among the Quadrwnana the thymus has, in the more anthropoid Apes, nearly the same general shape and relations as in the human subject, the cervical portion seems to be variously developed in different genera.\nAmong Cheiroptera the gland seems to be persistent in the genera Yespertilio and Ga-leopithecus, at least so far as anatomical inquiry has yet proceeded ; it consists of a thoracic portion embracing the base of the heart, and two cornua ascending parallel to each other on either side of the windpipe In a Bat which I dissected on the 20th of March, and which was then in a wakeful state, I could find no organ which I could positively conclude to be a thymus. On each side, however, of the root of the neck there existed a pretty large yellowish lobulated mass, resembling a good deal the aspect of a conglomerate gland. It consisted of conical lobes which were bounded and defined by a distinct homogeneous membrane exactly resembling the limitary tissue ; this was I think continued by reflection from one lobe to another, so as* to form a common envelope to.","page":1095},{"file":"p1096.txt","language":"en","ocr_en":"1096\tTHYMUS GLAND.\nall the cavities (fig. 731.). The lobular ca- consisted chiefly of aggregations of oil drops vities were completely filled by aggregations and molecules. Within the thorax at its of celloid particles, which were not manifestly upper part there was a similar lobulated grey-nucleated, nor provided with an envelope, but ish white mass, resting upon the lower part of\nFig. 731.\nConvexity of lobe from oil gland of Bat. A homogeneous membrane encloses a mu\u00ab itude of celloid particles,\u2014the exterior row of which alone is visible, the rest of the mass being quite opaque.\nthe trachea and the great vessels, and extending round so as to come in contact on each side with the lung ; the structure of this was precisely the same as that of the masses at the root of the neck, with which however it was not continuous. I am much inclined to regard these organs as representatives of the thymus, both from their structure and situation, and because I know not what else they could be ; they are not for a moment to be confounded with the ordinary adipose tissue.\nAmong Insectivora the thymus forms two nearly equal lobes, lying on the base of the heart and origin of the large vessels, with greater vertical than transverse dimensions. In some individuals, at least, it is not persistent throughout life, nor does it appear to be specially developed.\nIn two Hedgehogs which I dissected, one of which had been in a state of torpor until three days before death, and the other had been active and wakeful for several weeks, I found at either side of the root of the neck two roundish masses almost precisely similar in appearance to those existing in the same situation in the bat, and also two broader and thinner ones lying in the axillae ; but there was no trace of any such tissue in the thorax. The celloid particles were more loaded with oil than in the bat, especially in the dormant one, and in some parts they were more or less broken up and the oily matter diffused in the cavity. Respecting the existence of a real thymus distinct from these glandular masses I am in doubt, it is not altogether easy to distinguish the structure from that of lymphatic glands several of which lie upon the great vessels at their origin from the heart. However this be it is well worth remarking, that in two hibernating animals belonging to different orders, peculiar organs of precisely similar structure were found ; while, on the other hand, in a mole (an animal which I believe does not hibernate) I could find no unequivocal trace of thymus, nor of the peculiar oil glands which I have described as existing in the bat and hedgehog. This would indicate the existence of the oil gland to have reference to hibernation, but a more extended inquiry on this head is of course necessary before this suggestion could have much claim to be received.\nAmong Carnivora the thymus, except in the cat tribe, where it seems generally to vanish at an early period, is entirely thoracic, resting upon the upper part of the pericardium and the origin of the vessels. When mature \u201cit has considerable thickness and substance in the direction from before backward, and its right and left lobes irregularly overlap each other, so as to render the separation between them indistinct.\u201d When the gland becomes attenuated it assumes the form of a triangle, with the apex much prolonged upwards.\nThe thymus has been found by Mr. Simon in (young) seals, though other anatomists, including Meckel, who, as he says, was little likely to overlook its presence, had not observed its existence ; from this he concludes that it declines and disappears in this family, as in most other mammalia. Its form in the common seal, when present, is nearly symmetrical, consisting of two broad thickish lobes, which prolong themselves upwards to the root of the neck, and abruptly terminate by clubbed extremities, which are deeply grooved in front by the left vena innominata.\nIn the order of Marsupialia, three most eminent anatomists had failed to recognise the existence of a thymus, Mr. Simon has, however, discovered this gland in several instances, it is mostly placed on the pericardium, not reaching into the neck. In the foetus of the Kangaroo it has a peculiar conformation, being provided with a third, median, lobe projecting outwards between the two others.\nAmong Rodents the thymus differs in shape in the various genera. It consists in the rat of two elongated parallel lobes, reaching from the base of the heart to the root of the neck. In the hare it is much thicker, but still only extends to the root of the neck. In the hibernating rodents the thymus is believed to undergo at the approach of winter a remarkable alteration, apparently as a preparation for the long sleep of that season. Tiedemann describes in a Marmot, which he examined in the month of November while in a state of torpor, the gland as \u201c filling the whole of the anterior and posterior medias-tina, extending along the great vessels of the","page":1096},{"file":"p1097.txt","language":"en","ocr_en":"THYMUS\nneck to the vicinity of the lower jaw, spreading itself out above the clavicles on each side of the neck, and even passing behind the clavicles and pectoral muscles into the axillary spaces.\u201d Mr. Simon in his dissections of the same family finds the masses described by Tiedemann, as existing in the anterior and posterior mediastina, but not those in the neck, and states from microscopic examination the remarkable fact, that they all consisted of aggregations of fat vesicles. I do not gather clearly from his description whether these fat cells were surrounded by a limitary membrane, preserving the form of the thymic cavities, in all the situations where the fat masses are mentioned as existing ; i. e. whether all this fatty tissue was actually developed from the thymus, or a mere accumulation in the ordinary way : nor does Mr. Simon state whether the specimens he examined were in a state of torpor at the time of their death or not. I confess I should wish to have further evidence concerning the accumulations of fatin the marmot\u2019s thymus.\u2014I have never seen a really nucleated fat cell, nor have I ever observed any approach to such a development of nuclei. Tiedemann\u2019s description indicates so strongly a great difference between the conditions of the masses in question at the commencement of winter and in the summer, that it seems to me quite necessary that a comparative examination of their minute structure at both periods should be undertaken before the question of their relation to the thymus can be decided.\nIn Edentata the thymus is principally thoracic, the Sloth and Armadillo present small cervical prolongations connected to the larger mass by very slender strips.\nIn Monotremata a thymus is found resting on the origin of the great vessels, and scarcely extending into the neck.\nAmong Pachydermata there are marked differences in the form and development of the thymus. A fcetal Elephant presented a flat mass resting on the upper two-thirds of the pericardium, and sending upwards a short prolongation from its right lobe. In a Peccary the cervical portions were of great length, not only reaching to the angle of the jaw, but folded down again beside the trachea. So-lipeds have a thymus either entirely thoracic or reaching but a little way into the neck.\nAmong Ruminants, the Calf is usually referred to as exhibiting a thymus, which may serve as a type for the family. The gland presents cervical cornua which are highly developed, reach within the angle of the jaw on each side, and form large complicated masses up to the base of the cranium ; below, these prolongations are narrowed, and united in close juxtaposition to form an isthmus, which passes behind the first bone of the sternum, inclines to the left side, and expands into another considerable mass of glandular substance situated on the upper part of the pericardium and covered by the left pleura. In the Reindeer the submaxillary enlargements are absent, and the tracheal are of compen-\nGLAND.\t1097\nsative size. In the Fallow deer, again, the cervical portions are more developed, extending up to the cranium, but not reaching below quite to the pericardium.\nA thymus has been found in several Cetacea. In the fcetal Dolphin there are two large median portions, pericardiac and tracheal, with deep seated lateral connecting cornua : in the Mysticete whale there were two pericardiac lobes, from the right one of which a prolongation extended backwards across the arch of the aorta, between the art. innomin. and left carotid till it reached the trachea, and ascended a small distance in front of that tube to terminate in two little cornua : the left lobe was of much smaller size.\nAves.\u2014In the class of birds no organ unequivocally possessing the characteristic structure of a thymus had until lately been shown to exist. Meckel, indeed, described in diving birds an organ which he supposed to be peculiar to them, and which he considered to be the thymus. The microscope, however, in Mr. Simon\u2019s hand has demonstrated this organ to be merely a mass of fat, and that, too, even in the youngest specimens ; the same observer has succeeded in discovering a real thymus, which corresponds closely in structure with that of mammalia at an early period of development. It is found in the neck of very young birds, lying along the outer side of the superficial cervical vessels, extending from within a line or two of the base of the cranium to just above the inlet of the thorax. It appears as a semi-transparent ampullated tube closed at both extremities, and rather broader at its upper than at its lower part. Under the microscope it is seen to have walls formed by a distinct limitary membrane, and contents consisting of nuclei. The period of its disappearance varies somewhat, being earliest in the tribes of powerful and active flight, but in all occurring very much sooner than in mammalia.\nThis discovery of Mr. Simon\u2019s appeared to me of so much interest, both as regards the existence of the organ in birds, and the further elucidation of its structure which might be expected from the examination of the organ in a lower grade of organized beings, that I was anxious to repeat the observation.\nThe result was entirely confirmatory of Mr. Simon\u2019s description. Ina chick about one week old I found on each side of the neck a tube, which appeared ampullated to the naked eye, and which under the microscope exhibited a large central cavity with numerous irregular and slight lateral bulgings (fig. 732.). It was filled with imperfect nuclei, and with granular globules, which last were more numerous than usual ; there was also a quantity of oily matter in the form of minute drops or molecules. It was remarkable that on the right side the tube was divided into a number of separate portions, which seemed to have become quite isolated from each other ; this, I conceive, to have been the commencement of a process of degeneration, an idea which seems also favoured by the existence of","page":1097},{"file":"p1098.txt","language":"en","ocr_en":"1098\tTHYMUS\na quantity of oily matter as a deposit in the glandular cavities.\nFig. 732.\nLower end of thymic tube from chick one week old.\nDiameter at a 1-15 in.\nReptilia. \u2014 In the class of reptiles much uncertainty has prevailed respecting the existence of a thymus gland ; it has by some been confounded with the thyroid, by others denied to exist at all. The microscope has again in the same skilful hand cleared away the doubt, and rendered it certain that a true thymus is found in almost all reptiles, distinct from, and independent of, the thyroid. In young specimens of Chelonici there is found, extending upwards on each side along the carotid, or between it and the subclavian, an elongated white or yellowish mass, possessing the characteristic thymic structure, and easily distinguishable by this from the true thyroid, which lies in the median line between the carotids, near their origin. I have repeated Mr. Simon\u2019s observation on a tortoise, said to be about a year old, and found in the situation he indicates an\nGLAND.\norgan, which, though having to the naked eye somewhat the appearance of fat, is shown by the microscope to have the characteristic structure of a thymus. The lateral cavities are considerably more developed than in the brid, they are of very various size and somewhat irregular, bounded by a distinct limitary membrane, and filled with well formed nuclei, togother with a quantity of opaque granular-looking matter consisting of minute oily molecules. In Emydosauria the thoracic portions of the thymus are large and of prismatic shape, they meet on the base of the heart, overlapping the thyroid, and thence extend upwards along the carotid vessels to the base of the skull where they terminate ; in the lower part of the neck they diminish somewhat in size, but afterwards continue of uniform diameter.\nIn several Saurians (Lacertidae, Geckos, Chameleons) the thymus resembles that just described, save that the pericardiac portion is absent ; in adult specimens of others, as Isturius and Scincid\u00e6, no thymus has been detected, but a mass of fat exists just above the base of the heart, which may perhaps result from a transformation of the gland.\nIn Ophidia the thymus observes one un-deviating type of arrangement, it is found lying on each side along the carotid, often not strictly symmetrical, its lobes elongated and sometimes broken into two or more pieces. Most serpents possess a peculiar mass of fat which is developed in connection with the thymus, and often obscures or conceals it ; in two specimens of rattlesnakes Mr. Simon found this fat body was absent, but is inclined to believe it exists in those which inhabit the temperate latitudes. The thymus of serpents is supposed by Mr. Simon to be persistent, and to undergo transformation into fat.\nFrom the Batrachian reptiles it was natural to expect, that in consequence of the remarkable transformation which some of them undergo, and the intermediate condition maintained by others between reptile and piscine life, some important information would be gained respecting the true relation and import of the thymus. So it has proved ; for in the Frog only a mass of fat is found existing in the adult animal in the situation of a thoracic thymus, the very young animal, however, presents, in the same situation, true thymic structure, and the evidence of a real transformation of the gland, \u2014 not a mere replacement of it by fat,\u2014seems more perfect than in the case of the bibernators before referred to. It was now a point of much interest to determine the condition of the thymus in the fish-like batrachian larva before its transformation had occurred ; in none of these was any trace of thymus detected, while in the youngest individuals in whom pulmonary respiration had commenced the \u201c commencement of the organ\u201d was always to be found. Mr. Simon remarks ; \u201c The essential step in reptile metamorphosis is a higher developement of the respiratory system : as a part of this pro-","page":1098},{"file":"p1099.txt","language":"en","ocr_en":"THYMUS GLAND.\n1099\ncess we here find occurring the superaddition of a thymus gland, \u2014 its first appearance in the ascending scale of organization.\u201d Among the Perennibranchiata it is very interesting to observe, that the gland is gradually suppressed in proportion as the respiration becomes more completely aquatic, a thymus is found in the Menopoma, Amphiuma, Axolotl, and Meno-branchus, but not in the Siren or Proteus ; its position is rather peculiar, it lies in the neck, on each side, along the lateral aspect of the spine, just behind that prolongation of mucous membrane which unites the branchial cavity to the pharynx.\nPisces.\u2014In fishes Mr. Simonhas been unable to discover any trace of a thymus, after searching, carefully, in more than twenty genera ; this result accords well with the absence of the gland in the fish-like batrachian larva, and with its disappearance in the lowest Perennibranchiata.\nThe following are the conclusions which the eminent physiologist, so often referred to, deduces from a survey of his detailed and elaborate investigation. (L) The presence of the thymus gland is co-extensive with pulmonary respiration. (2.) Its shape and position are variable and unimportant. (3.) Its size and duration are, generally speaking, in proportion to the habitual or periodical inactivity of the animal. (4.) Where it remains as a persistent organ, it is usually but one of several means for the accumulation of nutritive material ; its continuance, under such circumstances is generally accompanied \u2014 though in some instances superseded \u2014by a peculiar accessory contrivance, the fat body.\nPhysiology. \u2014 The time is now past when an eminent physiologist could declare of the organs usually known as glands without ducts, \u201cthat in regard of their intimate structure and physiological meaning, they are all equally and utterly unknown to us.\u201d With respect to their structure, it may, I think, be said, that they are as well understood, or perhaps even better than the true glands, being in fact less complex, and their constituent parts less independent. Their physiological meaning, it must be confessed, is still obscure ; yet even on this dark part of the demesne of our science light is beginning to break, which we may fairly hope will continue to brighten.\nThe results afforded by examination of the thymus in the lower animals seem certainly to connect the gland most closely with pulmonary organs of respiration, and it would, therefore, seem a natural conclusion, that it subserves some purpose which has to do with the aeration of the blood. It is also found that the size of the gland may vary in a short space of time very considerably, that is, that its contents are capable of being absorbed very quickly, as proved by the fact mentioned by Mr. Gulliver, that in over-driven lambs, the thymus will soon shrink remarkably, and be nearly drained of its contents, but will become as quickly distended again during rest and plentiful nourishment. This seems to\nimply that the material necessary for the supply of the respiratory process is furnished by the thymus, which thus, in Mr. Simon\u2019s words \u201c fulfils its use as a sinking-fund in the service of respiration.\u201d The persistence of the gland, moreover, is observed to vary considerably according to the muscular activity of the animal, thus it disappears quickly in young oxen put to the plough, it endures longer in animals of quiet habits than in the restless and energetic beasts of prey, and vanishes at a very early period in the class of birds, while it persists long in that of reptiles. From this it seems to follow, that the use fulfilled by the gland in the service of respiration is more or less superseded when the muscular system is called into a high state of activity, i.e. when there is considerable waste of tissue yielding fuel for respiration. In the hibernating animal, where the gland, preparative to the winter sleep, is transformed into a mass of fat, its application to the demands of the respirtory process seems scarcely doubtful, as the chemical nature of the contents of its cavities is then peculiarly appropriate to neutaralise theoxydising agency of the air.\nProbable, however, as these views may appear, they have been confronted by the following weighty objections. An able physiologist, in the Brit, and Foreign Med. Review, observes, that the condition of young, rapidly growing animals, and that of hibernating animals, are rather opposite than pa-rellel, that whereas in the latter, the waste of the tissues is reduced to a minimum, in the former it is certainly greater than in the adult, so that there can be no deficiency of effete material to feed the respiratory furnace. The demand in the young creature is for plastic materials, out of which the rapidly growing and rapidly changing structures may be built up and renewed. \u201c On the other hand, in the hibernating animals all the nutritive actions are at zero, and the respiration for a long period is entirely dependent on the stores of fatty matter which have previously been set apart from the food. The demand is here for combustible materials.\u201d\nThe writer then observes, that the chemical nature of the contents of the thymus correspond so exactly at the two periods of active growth and hibernation to the kind of demand which must then exist in the system, that he conceives it more probable that the use of the gland at these times is different ; in the one slowly yielding up its hydro-car-bonous contents to supply fuel to the respiratory process, in the other performing the principal part in elaborating, by means of its myriad nuclei, fibrine from albumen, the plastic from the non-plastic element. \u201c As the demand for plastic material becomes less energetic the thymus diminishes in size and disappears, the production of plastic matter within the absorbent and sanguiferous vessels being then sufficient for the wants of the system. Or if the organ remains,\u201d its structure \u201c and the nature of its function changes,","page":1099},{"file":"p1100.txt","language":"en","ocr_en":"1100\nTHYMUS GLAND.\nand it cannot be deemed unreasonable to suppose that its use in the system should change also. In fact, that its use should be the same in the two cases, where its functions are so different, appears to us a very improbable supposition.\u201d Consonant with the above view is that of Mr. Paget, who remarks in his Report, that the fatty transformation of the thymus is an atrophy or degeneration of the gland, \u201c analogous to that atrophy by diminution or total removal of substance, which takes place once for all in the animals in which the thymus is not persistent. In each case the atrophy is an indication that the necessity for the ordinary acts of the thymus has ceased ; but in the hibernants it is, for new circumstances, made to minister to anew purpose, till at the expiration of the winter sleep, and the recommencement of new growth it begins again to be truly developed, and to form the more highly azotized organic compounds which it may restore to the blood for the nutrition of the fresh growing tissues.\u2019\u2019\nOn a careful consideration of the theories now noticed (and no other are worthy of any examination), it seems to me, certainly, that the latter is nearest the truth ; and that we cannot regard the thymus in the young animal as a mere preparer of material fitted to support the respiration. The following arguments must be allowed to weigh strongly against Mr. Simon\u2019s view. (1.) The chemical constitution of the thymus, consisting chiefly of proteine and not of fatty matters, seems by no means to be such as would be best adapted to sustain the supply of combustible material required in respiration. (2.) The office of serving as a reservoir for material to be used in respiration may be attributed with much more probability to the liver*, the construction ot which, as also in some measure its position relative to the circulatory system, point it out as peculiarly adapted for the reception of superfluous respirable material from the blood, and equally so for rendering it up again, when the demand again begins to be felt in the circulating current. Of this, the condition of the liver in fish, and generally in all animals, in whom the respiration is of a low type, is sufficient proof. Now as the liver is of greater relative size in the young than in the adult animal, it is not likely that this one of its functions is in any measure discharged by the thymus. (3.) The anatomical constitution of the thymus is very unlike that of an organ which serves\n* I may just briefly mention here the results to which I have been led by a long and careful study of the liver in vertebrata. Its lobules (if it is so divided) are not penetrated by excretory ducts, nor are the secreting cells contained as in most other glands in the cavities of ducts, they lie naked in the interstices of a close plexus of most delicate-walled, capacious, capillaries, from which they readily receive the materials they are intended to act on ; and to which they as readily render up their elaborated products when these are called for. The excretory ducts, consisting at their origins almost solely ot nuclei, attract into their cavities the oleo-bihary secretion with which they are bathed ; probably> however, in so doing altering it to some extent.\nas a reservoir of respirable matter. For this purpose we should expect to find a fluid stored up in cavities, such as the oil of the fat vesicles, or the oleo-biliary matter which i collects within the cells of the liver ; the anatomical elements, however, of the thymus are totally different, being mere nuclei, with no j trace even of commencing cell development, in fact, just that part of a glandular apparatus which is not the secretion, however important a part it may play in the elaboration of it. (4.) The transformation of the thymus into fat previous to the winter sleep, concurrently with the formation of other fat 1 masses in the axill\u00e6,indicates, as above shown, very strongly that the gland in its natural state fulfils some purpose different from that to which it is subservient during hibernation. But as there can be no doubt that it undergoes this change for the sake of the respiratory function, \u2014 to fit itself for supplying those demands during the long period when the waste of the tissues is reduced to a minimum, and no ingesta are taken,\u2014it seems tolerably certain that while the gland continues in its normal unchanged state, its action must be of a different kind, not having special reference to the function to which during hibernation it undoubtedly ministers. The circumstance quoted by Mr. Simon from the writings of Mr. Gulliver, respecting the remarkable shrinking of the thymus in over-driven lambs, cannot be regarded as proving that the contents of its cavities are thus absorbed solely for the use of respiration. It is more probable that they are resumed into the blood, which has begun to be impoverished by fasting and exercise, in order j that they may go to supply the nutrition of all parts indifferently. With regard to the arguments adduced by Mr. Simon from Compara- ! tive Anatomy, to the effect that a thymus has some essential connection with \u2019pulmonary organs of respiration, I would remark that though it is certainly of weight, yet it cannot be regarded as proving absolutely that the two organs are co-related in function.\nIt may be that they are only simultaneously developed, \u2014 connected together in virtue of some law of organized being which requires their coeval appearance, and yet not intended to minister to a common pupose.* I grant that observing their consentaneous appearance, one should inquire whether they be not essentially linked together in function, but if j this be not proved by subsequent inquiry, or \u00e0 fortiori, if it be shown to be unlikely, then the argument arising from their co-development ceases to have much force.\nBut if we decline accepting the theory proposed by Mr. Simon, are we to close, unconditionally, with the other which has been above expounded, and which is but a modifi-\n* This is perhaps the more probable, seeing that the thymus does not assert its connection with organs of respiration taken generally, but only with a particular modification of them, so that its existence is determined not so much by the degree in which the function is fulfilled as by the mode. Hence it is absent in the higher fishes and in insects.","page":1100},{"file":"p1101.txt","language":"en","ocr_en":"THYMUS GLAND.\ncation of a former opinion, that of Cowper and Haller, who regarded the thymus as belonging to the class of conglobate glands. It appears on the whole more consistent with the various facts bearing on the subject which are in our possession, and yet it is by no means proved, and is open to some objections. In the first place, one is inclined to look suspiciously on any hypothesis, which assigns the production of a material almost universally diffused throughout the body to any separate organ, it seems far more truth-like to regard the manufacture of the plastic element (fibrine), as taking place in the blood itself by the agency of the white corpuscles, as Drs. Addison, Williams, and Carpenter, have well nigh demonstrated to be the case. If their view be correct, it becomes still more improbable that the thymic nuclei should be the producers of fibrine, seeing that they are altogether dissimilar in appearance and structure from the white granular corpuscles. Moreover the early disappearance of the thymus in birds, long before the demand for plastic material can have materially diminished, makes it unlikely that in them its function is the elaboration of fibrine. The same observation applies to mammalia though in a less degree; and, generally, I think there can be little doubt that the self-forming, self-sustaining blood, while supplied with an adequate quantity of proper nourishment, is fully capable of evolving within itself all that is requisite for the nutrition of any part of the system.\nIt seems almost unwise to broach any further speculations respecting this ignotum quid, especially after stating objections to the views of others ; and yet while ideas are offered as mere suggestions, to serve if they may as aids to the discovery of truth, they are not without utility, since none can say without trial which of these \u201c scintillas \u201d may kindle the light of truth. From the careful investigations which have been made respecting the age at which the gland attains its highest development, and the conditions which chiefly affect its size and repletion, it certainly appears to be a very exact exponent of the state of the nutrient processes generally,\u2014a delicate barometer of nutrition, as Mr. Simon terms it. Moreover its anatomical constitution, as 1 have insisted, seems to show that it does not truly secrete, i. e. elaborate and separate some peculiar principle from the blood, but that it is a congeries of (nuclear) particles, which can only be regarded as solidified liquor sanguinis, and not in anywise as a true secretion, especially when we remember that in every such fluid the nuclei of the producing cells sooner or later disappear. Chemical analysis, as we have seen, confirms this position ; the formula expressing the nature of the contents of the thymic cavities being identical with that of proteine.\nNow if one of the organs which belong to the class of ductless glands have for its function to act as a living attractive recipient or reservoir for the blood en masse, may not an-\n1101\nother fulfil its destined purpose by serving as a reservoir for that part of the blood which ministers to nutrition, perhaps for the plastic element of the liquor sanguinis in particular ? When such plastic material is in superabundance in the circulating current, a quantity of it passes off, and solidifying in the thymic cavities, assumes that most universal of all organized forms, the form of nuclei.* When there is again a demand for such material, the solidified particles would again liquefy, and re-enter the impoverished blood. It is not difficult to understand that such a function may be most necessary during the period when growth is most active, the supplies of nourishment most frequent, and the waste of the tissues most rapid, but that as the several nutrient processes, both of the assimilative and destructive kind, attain to more steadiness and equilibrium, diminishing somewhat in their intensity and rapidity, but increasing in real strength, firmness, stability, and perfection (one is obliged to use somewhat metaphorical language), it may no longer be requisite, and the organ will therefore undergo a gradual atrophy.\nThis hypothesis, which is really little else than an expression of the facts above noticed, has been principally suggested by the consideration of the nature of the secretion (so called) of the thymus, wherein it differs ab-solutely from all other glands, in as much as the nuclei constantly remain in their primitive state, and are not even mingled with granular matter ; while it agrees in this respect with another organ of similar kind, the spleen, whose parenchyma consists of similar bare nuclei, which exert so far as we know no real secretory action. It is however by no means improbable, that, even if this guess at the use of the thymus be correct, we are yet very far from being fully acquainted with all the reasons why it exists, and why in such a situation, and under such a form. If Mr. Goodsir\u2019s account of its origin, from a portion of the blastoderma, with the suprarenal capsules and thyroid, be correct, it is possible that its formation may be demanded by some recondite law of development, in virtue of which the extraction of one organ out of the primitive blastema necessitates, by a kind of compensating action, that another should arise in some sense complementary to it. This idea, originally stated by Treviranus, has been developed very ably and pleasingly by Professor Paget, to whose lectures I refer for a full exposition of it.\nMorbid Anatomy. \u2014 Not much is known, and probably there is not much to be known, respecting the morbid conditions of the\n* I would here direct attention to the remarkable fact, that in all glandular, and in fact in almost all, organs, the nuclei are almost precisely similar in size and appearance, and do not differ from each other in different parts more than individual ones do in the same. Does not this indicate strongly a tendency of liquor sanguinis effused in conditions of healthy nutrition, to assume the form of nuclei, irrespective of the situation or special endowment of the part where it is effused ?","page":1101},{"file":"p1102.txt","language":"en","ocr_en":"1102\nTHYMUS GLAND.\nthymus. Absence of the gland has only been observed in cases of acephalism, where the brain and many other parts are simultaneously deficient, while in cases of anence-phalism, where the brain is also wanting wholly, but the general development much more complete, the thymus is present ; nothing therefore can be concluded from its absence in cases of extreme monstrosity as Mr. Simon has well observed.\nInflammation of the gland, if it ever happens, is of rare occurrence. Professor Hope, however, refers to a case by Mason, in which an abscess of the thymus is said to have opened into the trachea.\nThe same author states that Becher and Hangstadt have collected about fifteen examples of persons, of different ages, affected with more or less general tubercular disease, in whom the thymus was found involved. \u201c It was for the most part considerably enlarged, very firmly united with surrounding parts, and either converted by tubercular infiltration into a hardened mass, or else partially destroyed by tuberculous softening. In three or four instances calcareous concretions, probably resulting from the retrogression of tubercle, were discovered in the gland.\u201d\nHaller speaks of the thymus as being frequently affected with scirrhus along with the conglobate glands ; but though Becher gives an instance on his own authority, and refers to others, there can be no doubt that true malignant disease of the gland is extremely rare. Sir A. Cooper gives a case, in which death was produced by the pressure of an enlarged thymus upon the vena transversa and upon the trachea, probably also upon the vagi nerves ; there was severe dyspnoea and oedema of the lower extremities. He considers the disease to have been of the fungoid kind, i. e. encephaloid.\nAtrophy of the thymus occurs as a normal event ; if, however, it should take place long before the usual period, determined, as we have seen, not so much by the lapse of time as by the condition of the system, it must be regarded as morbid. Yet in every such case it is almost certain that the atrophy of the thymus would be but part of a general malady, wherein the nutrition of every organ was greatly impaired.\nHypertrophy of the thymus has attracted more attention, Dr. Kopp having noticed several cases of suddenly fatal dyspnoea occurring in children, in whom the gland was found of large size, concluded that there was some essential connection between the glandular enlargement and the suffocative paroxysms. The fallacy of this opinion has been well pointed out by Mr. Simon and others. I must refer to his work, and that of Professor Hope, for a full account of their arguments, and will only mention two circumstances, which seem to me conclusive upon the point. The first is, that \u201cthymic asthma\u201d may occur with an unnaturally small thymus ; the second, that when a thymus, enlarged by malignant disease, as in Sir A. Cooper\u2019s case, does oc-\ncasion dyspnoea, it is not sudden and paroxysmal, but constant and exhausting.\nFor the history of the thymus, and for a copious list of authors who have written upon it, I can do no better than refer to the Historical Introduction to Mr. Simon\u2019s essay.\n(C. Handfleld Jones.)\nTHYROID GLAND. (French, glande thyro\u00efde ; German, Die Schilddr\u00fcse ; Italian, Tiroidea glandola ; Latin, Glandula thyroid\u00e6a.) The organ which has received this name is a bilobed glandular body, situated in the human subject in close proximity to the larynx, from the prominent cartilage of which it has probably derived its appellation.\nIts size varies considerably in different individuals, according to unknown peculiarities. In the female it is generally larger than in man ; reversing thus the proportion which obtains between the vocal apparatus in the two sexes, and so far negativing the idea, that the larynx and the thyroid gland are in any wise intimately connected.\nThe normal iveight of the thyroid is about one ounce, according to Cruveilhier. Any great excess above this must be regarded as indicating a pathological condition.\nIts form, as has been said, is bilobed ; the lateral lobes being united by a thinner and narrower portion termed the isthmus. It would appear (from the circumstance that variations of form are most frequent in the isthmus, which sometimes is even wanting) that the lateral lobes are the primary parts of the gland, and, in fact, in one entire class (that of birds) the lobes lie entirely separate, one on each side of the trachea. In the human subject they are large and solid, presenting an anterior convex surface, a posterior concave, an external and inferior border which is convex, and runs up to join the superior interior concave border in a pointed cornu, which reaches as far as the origin of the inferior constrictor pharyngis from the ala of the thyroid cartilage. From the upper border of the isthmus, or from the adjacent part of one of the lateral lobes, there stretches upwards a narrow strip of glandular tissue, which has been called the pyramid or mesian column, and which may have been sometimes mistaken for a muscle, as Cruveilhier asserts ; though it is distinguished perfectly from the so called levator gland, thyroid, by Haller. This prolongation sometimes extends to the hyoid bone, but generally not so far, and is subject to numerous modifications of shape and structure. The following list of the various forms which the thyroid may present, is taken from the catalogue of the museum of Guy\u2019s Hospital, which Dr. Birkett, the curator, most kindly allowed me to inspect, together with the preparations. 1. Thyroid without an isthmus, but having two mesian columns. 2. Thyroid almost without an isthmus, and having one mesian column. 3. Thyroid with broad isthmus and one mesian column. 4. Thyroid with no isthmus, but having one large mesian column. 5. Thyroid","page":1102},{"file":"p1103.txt","language":"en","ocr_en":"THYROID\nwithout isthmus, having one column (right), and an isolated portion on the left. 6. Thyroid with one lobe only developed, and a little glandular body below the middle of thyroid cartilage. 7. Thyroid gland replaced by a membranous substance, two small portions only remaining. 8. The gland with isthmus and two mesian columns.\nIt is important to ascertain accurately the situations and relations of the thyroid. I give them as they are stated by Cruveilhier, and confirmed by my own observation. The isthmus lies across the first four rings of the trachea, the first not being completely covered.* Its upper margin is about half an inch below the inferior border of the cricoid cartilage : from it the mesian column passes upward, lying upon the crico-thyroid muscle, the thyroid cartilage, and the thyro-hyoid membrane. The lower border of the isthmus is free, and occasionally descends so low, that there is not space between it and the sternum to perform the operation of tracheotomy. Posteriorly, the isthmus is firmly attached to the rings of the trachea by close and dense areolar tissue. The sterno-hyoid and sternothyroid muscles overlap the greater part of the isthmus ; a small portion, however, in the median line is covered only by deep cervical fascia, and perhaps crossed by some branches of origin or communication of the anterior jugular veins. The lateral lobes, concave posteriorly, embrace, and rest against the sides of, the trachea, the cricoid cartilage, the inferior and lateral parts of the thyroid cartilage, and the lower part of the pharynx and upper part of the oesophagus. \u201c These lobes form, with the connecting isthmus, a half or sometimes three fourths of a canal, which surrounds all these parts. This relation, one of great importance, explains how certain goitres flatten the trachea laterally, hinder deglutition, and finally bring on a real asphyxia from strangulation.\u201d')' The posterior border of the lateral lobes corresponds to the vertebral column, and rests upon the carotid artery ; but, if enlarged, it extends further outward, and lies upon the jugular vein. Both recurrent nerves ascend behind the lateral lobes, and are closely in relation with them as they pass under the lov/er edge of the inferior constrictor muscle. Anteriorly, the sterno- and omo-hyoid muscles pass in front of the lateral lobes, the sternothyroid is stretched as a thin band over their surface, and in cases of considerable hypertrophy may be seen sunk in a deep groove formed in their substance, or, as Cruveilhier states, expanded to a width double or treble its natural size. These muscles separate the thyroideal lobes from the sterno-cleido-mas-toid, which, with the mastoid artery and the superficialis descendens on its inner surface, overlaps their greater extent, as it passes backwards and upwards to its cranial attachment. \u201c The superior extremity of each of\n* There is probably some variation in this, according to the varying depth of the isthmus.\nf Cruveilhier, Anat. Descr.\nGLAND.\t1103\nthe lateral lobes terminating in a point, whence the bicorned form which has been attributed to the thyroid body, corresponds on the inside of the carotid artery to the lateral and posterior part of the thyroid cartilage, and extends sometimes even to the neighbourhood of its upper border. The inferior extremity, thick and rounded, descends more or less low in different subjects, and corresponds to the fifth, sixth, or even to the seventh ring of the trachea; it is situated between the trachea and the common carotid artery. By the inferior extremity the inferior thyroid artery reaches the gland.\u201d \u201c The superior border is concave, and skirted by the superior thyroid arteries.\u201d The inferior is convex, and has branches of the inferior thyroid running along it.\nThe thyroid gland is of a red or reddish yellow colour, of tolerably firm consistence, and gives to the touch the sensation of granulations. Cruveilhier, thus describing, proceeds as follows : \u201c This organ presents all the anatomical characters of glands, and, like them, is separated by dissection into glandular grains \u201d (doubtless meaning the acini of Malpighi) ; \u201cbut there is, between these glandular grains and those of ordinary glands, this difference, that in the thyroid gland the glandular grains communicate with each other, while in the others they are independent.\u201d He then details the result of mercurial injection, to show that the glandular grains, or granulations, have a vesicular structure, and communicate with each other ; this latter statement, however, is certainlv erroneous, as we learn from more accurate modes of investigation. The presence of a certain amount of secreted fluid, in the natural condition of the tissue of the thyroid, and the accumulation of a similar material in larger quantities under certain morbid conditions, the eminent French anatomist justly regards as evidence of the thyroid possessing a secreting apparatus ; but, at the same time, faithful to the results of accurate dissection, he acknowledges that no excretory duct can be found leading either into the trachea, the ventricles of the larynx, or the foramen c\u00e6cum of the tongue, whither earlier observers had, with too nice refinement, sought to trace its course. Far truer and more physiological than such straining after uniformity is the conclusion he adopts : \u201c I think that there exist, in the economy, glands without excretory ducts, such as the thymus, the suprarenal capsules, and the thyroid gland. The liquid produced in the gland is absorbed entirely, and fulfils unknown uses.\u201d I have thought it worth while to follow this accurate and trustworthy anatomist through his account of the structure of the thyroid, though it be somewhat antiquated, partly for the sake of the confirmation it affords to the results of a more recondite and powerful analysis, and partly that we may observe how securely we may trust Nature\u2019s own teachings, even when they may appear, for a time, contradictory to established doctrines, as doubtless it must","page":1103},{"file":"p1104.txt","language":"en","ocr_en":"] 104?\tTHYROID GLAND.\nonce have been considered that a gland should exist unprovided with an efferent duct.\nI now proceed to give a more detailed account of the structure of the thyroid gland. Its surface is somewhat uneven, \u2014 a natural condition which is often greatly exaggerated in hypertrophy of the gland ; it is traversed by several large branches of the nutrient arteries, which ramify over it before they plunge into its substance. A thin fibrous expansion, continuous with the sheath of the cervical vessels on each side, forms a capsule which invests the gland, and from whose inner surface septa dip into the interior, dividing its substance into lobes and lobules much after the manner of a conglomerate gland ; these fibrous septa are often well seen in sections of hypertrophied specimens. A thin slice of the thyroid, examined under a low power of the microscope, displays its constitution very perfectly and readily (fig. 733.)\nIt is seen to be made up of closed vesicles, aggregated together in groups of various size by the fibrous expansions just described. The form of these vesicles is primarily spherical ; but many, perhaps the majority, are more or less affected by mutual pressure, being triangular, elongated, ovoid, or oblong. They are all perfectly closed, the wall being formed by an homogeneous limitary membrane, which is easily traced all round, and can never be seen passing off into a neck, or blending with the envelope of an adjacent vesicle. Where a number of vesicles lie closely crowded together, the homogeneous envelopes are of \\ course in contact, or separated only by the interjacent vascular plexus ; but those forming the surface of a group are invested by a thin expansion of fibrous tissue derived from the general capsule. The diameter of the vesicles of the human thyroid I have found to range from g\u00f6V\u00f6 inc^ t0 irV\nFig. 733.\n'A group of vesicles from, the thyroid gland of the bullock.\nThey contain the vesicular epithelium, and that consisting of nuclei and granular matter, in varying\nproportions.\ninch ; in the bullock, from\tinch to\n\u25a0gL inch ; the greater number averaging about inch, in this animal as well as in the pig. In the mesian column I found, at least in one instance, that the structure was essentially the same as that of the thyroid itself, only that there was a much greater amount of fibrous stroma, which resembled more nearly ordinary areolar tissue, containing both the white and yellow element.\nThe vesicles are lined internally by an epithelial stratum, consisting usually of nuclei set closely together in a scanty basis substance (fig. 734.), which is either feebly granular, or of a somewhat oily aspect. The nuclei are at once recognised by the practised eye as exactly resembling those of the true glands. Their nucleoli are not always visible, and vary\nFig. 734.\nEpithelium from thyroid of bullock.\nFig. 735.\n\nEpithelial particles fro thyroid of rabbi f\nDiameter in.'\nvery much in number \u2014 from one to four or five. The nuclei are, however, always vesicular, bounded by a strongly marked envelope and have a mean diameter of a ^ ^ th inch. It has been observed by Mr. Simon, and I have occasionally had the opportunity of","page":1104},{"file":"p1105.txt","language":"en","ocr_en":"THYROID GLAND.\t1105\nconfirming the remark, that the nuclei, instead of remaining in their primitive condition, proceed to the further stage of cell development ; this he has noticed both in man and in several of the lower animals. I should say that it is certainly a circumstance of rather rare occurrence ; but it is worth remarking, that it may be artificially produced by adding to the specimen some coagulating re-agent, which speedily solidifies a film of albuminous plasma around the nuclei, and thus produces very good imitations of cells. The epithelium of the thyroideal cavities often assumes the form of small vesicles larger than the nuclei (see figs. 736, 737, 738.), and easily distinguished\nFig. 736.\nVesicular epithelium from Human thyroid. Diameter of vesicles, 3_20\u00d6\u00d6 *n'\nFig. 737.\nVersicular epithelium from thyroid of Pig. Diameter of vesicles, 2_T\u00f4\u00ef\u00ef\u00fc iQ-\nFig. 738.\nVesicle from thyroid of Hedgehog, lined by an epithelium consisting of a double row of pellucid delicate vesicles, in. diam.\nfrom them* The diameter of these in a human subject averaged 20100- inch; in a bullock, about\tinch. They are, in their natural\nstate, perfectly spherical, but often somewhat angular from mutual pressure. Their contents are a very faintly granular or pellucid material, which does not surround a nucleus except iu some rare instances, where there may be seen an imperfect trace of one. These vesicles, which I thus name to distinguish them from the nucleated cells occasionally met with, exist in the glandular cavities, sometimes alone, sometimes mingled with the ordinary form of epithelium in varying proportion. I am inclined to believe that they originate in the nuclei, which undergo a kind of expansion, at the same time losing their nucleoli. This opinion needs further confirmatory evidence ;\n* I am obliged to use the same word (vesicle) in speaking of the large glandular cavities, and of the epithelial particles which line them ; the distinction between them should, however, be carefully borne in mind.\nVOL. IV.\nit is, however, certain, that they are not developed upon pre-existing nuclei. The layer of epithelium is generally of no great thickness, not occupying more than one eighth or one sixth of the distance from the envelope to the centre of the cavity; in the rabbit, however, it appeared to be more abundant, encroaching considerably on the interior, which, in this instance, was not filled with the characteristic glistening secretion. In a section prepared in the ordinary way, a large quantity of epithelium is broken up, and may be seen strewn over the field. Not unfre-quently, however, the nuclei adhere firmly together; and sometimes, as in the pig, I have seen the greater part of the lining of a cavity detached entire.\nThe contents of the cavities are for the most part a clear, somewhat refracting, homogenous material, which is manifestly the product of secretion, and fills all the spaces not occupied by the epithelium : this fluid is sometimes contained in small vesicles yiy to 2w\u00f6 inch diam. (figs. 739. and 740.) which have a\nFig. 739.\nO\nTwo vesicles containing a transparent matter and no epithelium. From thyroid of Bullock; the larger in., the smaller rJ5\u00fc in. diam.'\nFig. 740.\nTwo vesicles from thyroid of Bulloch, having a thicker lining of epithelium than usual, and each containing a single vesicle, whose wall, of homogeneous membrane, surrounds the central cavity of the original vesicle.\nwell marked, structureless envelope, but are destitute of any thing like epithelium. They may be seen occasionally in the interior of the glandular cavities, and also floating free in the field of view, having been perhaps detached from cavities opened by the section. The exact import of this circumstance does not appear ; for I cannot regard them as newly formed glandular vesicles, developed within the original ones in an endogenous manner. Were this the case they would occur more frequently, and would exhibit some traces of epithelial lining. Large crystals, sometimes\n4 u","page":1105},{"file":"p1106.txt","language":"en","ocr_en":"THYROID GLAND.\n1106\nof well marked prismatic, sometimes of octo-hedral, form, are seen occasionally in the glandular cavities. They are generally single in each, and I have no other guide than their form to lead me to any opinion respecting their chemical constitution. I have seen, in a human thyroid, some large oval or circular corpuscles about yoVtr inch diam., consisting of coarse granular matter not surrounded by any distinct envelope, and of an opaque dead white colour. These were perhaps abnormal formations ; yet in a tortoise, where the gland was quite healthy, similar corpuscles, and more numerous, were observed. The clear fluid material, contained within the glandular cavities, is generally spoken of as of an albuminous nature. This opinion seems confirmed by two analyses of the gland, made by my friend Mr. Beale, which may be regarded (after allowance is made for the areolar tissue, vessels, envelopes, and epithelium) as expressing pretty correctly the chemical nature of the secretion which forms so large a part of the whole bulk. These analyses I will presently quote, but will first detail a few observations of my own, as to the effects of certain reagents on the fluid in question.\nLiq. Potassce, added to a thin section prepared for the microscope, rendered it much more transparent, partially dissolving the epithelium, and leaving a quantity of oily matter diffused throughout it. Acetic acid now added to the specimen pretty nearly restored it to its former appearance, but did not bring into view any precipitated protein. Acetic acid, alone, dissolves in part the epithelium of the vesicles, and renders the fibrous tissue more transparent. Liq. Ammoni\u00e6 dissolves the epithelium in great part, but does not alter the transparent contents of the cavities ; nor does liq. potass\u00e6 or acetic acid. Solution of iodine does not materially affect the epithelium of the cavities, but renders it more opaque. Strong nitric acid at first renders the epithelium more opaque and granular, but does not manifestly affect the contained secretion. After a time it colours this material bright green or yellowish green, and disengages a great many bubbles of gas. A saturated solution of bichloride of mercury, even after long maceration, does not seem materially to affect the secreted contents of the vesicles ; it makes their peripheral stratum of epithelium quite opaque ; but the interior still appears transparent and glistening.\nThe chief conclusion deducible from the above results is, that the secreted material of the glandular cavities of the thyroid is not ordinary fluid albumen ; as otherwise it would certainly be coagulated by the agents employed. The effect produced by nitric acid is also worthy of notice, though I cannot explain the meaning of it.\nAnalysis of thyroid gland.\n\t\tHuman.\tOx.\nWater\t-\t-\t70-6\t71*34\nSolid matter\t-\t- 29-4\t28*66\n\t\t100\t100\nSolid matter.\nAnimal (fibrinous and\nalbuminous) matter,\tHuman.\tOx.\nvessels and fat -\t26*384\t24*628\nExtractive matter Extractive matter with\t1*7\t\ngelatine\t\t2*888\nAlkaline salts\t0*5\t0*642\nEarthy salts\t0*816\t0*502\n\t29*400\t28*660\nThe analyses given above testify to the\t\t\npresence of a large quantity of fibrinous and albuminous matters in the gland, and leave no doubt that its secretion is a protein compound; it is, however, unfortunately impossible to procure a sufficient quantity apart from other substances to analyze correctly ; and the exact nature of the thyroideal secretion consequently still remains unknown. Thus much, however, seems to be ascertained, or rendered very probable. (1) That the secreted material is of an albuminoid nature. (2) That it is not in the state of ordinary fluid albumen. (3) That gelatine is sometimes an ingredient of the secretion; (it was found in the gland of an ox, but not in that of the human subject, and consequently could not have been derived from the fibrous tissue). (4) That though crystals of triple phosphate and of oxalate of lime occur in the cavities, no urea nor lithic acid, nor in fact any special organic compound, can be detected.*\nVessels. \u2014 The vascular supply of the thyroid is very abundant, and completely justifies Cruveilhier\u2019s opinion, that more than a mere process of nutrition is carried on in the gland.\nThe arteries which are distributed chiefly to this organ are very constant in their number, and tolerably so I think in their respective dimensions, though in this respect they vary inversely with regard to each other. They ordinarily arise, as has been well remarked by Mr. Simon, just beyond the points where the arteries to the brain are given off from the large trunks,\u2014a circumstance which he conceives to be very significant of the function of the gland which they supply ; \u2014 the two superior thyroideal arising one on each side from the external carotids, almost immediately after the bifurcation of the common carotids, and the inferior thyroideals from the intra-scalenal portion of the subclavian, almost opposite the point where the vertebrals are given off. A fifth thyroideal artery occasionally exists,\u2014that named after Yenbauer; taking its origin from the arch of the aorta or thearter. innominata. The superior thyroid not unfrequently takes origin a little lower clown from the division of the common carotid, or even from its trunk ; or it may arise higher up from a common trunk with the lingual. It courses first forward and inward, when it is\n* I would not omit to express here my obligations to Mr. Beale for undertaking the analyses, and for the care and skill with which he has performed them.","page":1106},{"file":"p1107.txt","language":"en","ocr_en":"THYROID GLAND.\tU07\n\u2022covered only by the deep fascia and platysma ; but it soon turns vertically downwards, and runs beneath the sub-hyoidean muscles to the upper extremity of the gland, where it divides into three branches ; one of these runs between the thyroid gland and the trachea, a second skirts the external border of the lateral lobe, while the third, running along the internal border, forms an anastomosis with the corresponding branch of the opposite side.\nThe inferior thyroid is noticed by Cruveil-hier as one of the arterial branches most liable to vary in its origin,\u2014an opinion which, emanating from a less high authority, I should have been inclined to question. It may arise, acccording to him, from the common carotid, the arch of the aorta, or the arleria innomin-ata. (The supra-scapular often, less commonly the posterior scapular, and sometimes even the internal mammary, spring from the commencement of the inferior thyroid, which is therefore called the thyroid axis.) Its course is peculiar ; it runs at first straight upwards, then comes downward, and again ascends to reach the inferior extremity of the lateral lobe of the gland. It passes in front of the trachea, and behind the great vessels and vagus nerve : the connecting cord of the sympathetic descends behind it to the middle cervical ganglion when it exists, which is then almost constantly found, as it were, seated astride upon the vessel, exactly on the convexity of its first curve. Like the superior thyroid, it has three terminal branches, one running along the inferior border of the gland, another breaking up over the posterior face of the lateral lobe, and a third which penetrates between the gland and the trachea, and anastomoses with the one of the opposite side along the upper border of the isthmus. (Cruveilhier).\nThe capillary plexus, in which the minute branches of these arteries terminate, is disposed in the form of hollow spheres around the glandular cavities, closely applied upon the limitary membrane and forming a continuous network throughout the gland. It is tolerably close-meshed, but not nearly so much so as that of the liver or kidney. The diameter of the capillaries, in a recent injected specimen, varied from g-.^V\u00fc-\u00f6 inch, and the interspaces were, I think, two or three times as large.\nThere are corresponding ven\u0153 comit\u00e9s to the superior and inferior thyroideal arteries. The superior thyroid or thyro-laryngeal returns its blood either into the internal jugular vein, or into the common trunk of the facial and lingual, before it joins either of the jugulars. The middle thyroideal runs down and turns aside, crossing the common carotid to enter the internal jugular. Besides these there exist constantly another pair of veins, which run down in front of the trachea involved in the deepest layer of cervical fascia, and terminate either by opening both into the vena transversa, or the left into this trunk, and the right into the junction of it with the right brachio-cephalic. These veins run down, gradually diverging from each other ; so that, from being at their origin no more than one third of an inch\napart, they are separated at the lower part of their course by an interval of about an inch, or rather more. In this situation they are often united by a transverse branch, and are said, by Cruveilhier, to form, with the tracheal and laryngeal veins proceeding to unite with them, a considerable plexus, which it is impossible to avoid in the operation of tracheotomy. These veins correspond in some measure with the thyroideal artery of Yenbauer, but are much more constant, and are sometimes three or four in number; so that the blood they return is not proportioned to that conveyed by the artery.\nThe lymphatics, originating probably in a closed network, proceed to enter the deep cervical glands. They may sometimes be seen filled with a concrete albuminous substance, which they have probably taken up from the glandular cavities.\nNerves.\u2014 The recurrent laryngeal, shortly before it passes under the margin of the inferior constrictor muscle of the pharynx, gives off some filaments to the thyroid gland ; some are also furnished by the external laryngeal ; while a plexus, derived from the middle cervical ganglion, proceeds along the inferior thyroid artery, and is distributed to the gland along with its branches, forming communications with the preceding. In thin sections of the thyroid treated with acetic acid, I have seen the nucleated bands of the sympathetic, containing one or two c\u00e6lio-spinal tubules, running for some distance in the interspaces of the vesicles ; they probably terminate by forming a looping plexus ; but I have not been able to ascertain anything certain on this head respecting either these or the tubular fibres.\nDevelopment. \u2014 The thyroid is said by Cruveilhier to be developed by two lateral halves, which are subsequently united by means of the isthmus. This statement seems to be confirmed by the condition of the gland in several of the lower animals, where the lateral lobes continue separate, lying on each side of the trachea ; and is also supported bv the occasional occurrence of a similar disposition in the human subject.\nIn my own researches it has not occurred to me to observe this mode of development, perhaps because I have not examined specimens at a sufficiently early period ; however, in an embryonic sheep only two inches long, where the thyroid was distinctly visible, it presented the usual appearance\u2014the lateral lobes being connected by a narrow isthmus ; the same was the case in a human foetus of 4\u00a3 months ; the isthmus, however, being wider, and not appearing to be of at all more recent development than the lateral lobes. In the embryo of the sheep just mentioned, the gland was of an opaque whitish aspect, differing materially from its natural reddish colour ; it consisted principally of nuclei, with a small quantity of granular matter. Scarce any trace of a vesicular arrangement existed ; but the whole mass was surrounded by an investing membrane very nearly homogeneous in texture. In another embryonic 4b 2","page":1107},{"file":"p1108.txt","language":"en","ocr_en":"1108\tTHYROID GLAND.\nsheep, three inches long, the thyroid was much more of its natural reddish, semi-translucent colour ; still there was scarcely any vesicular arrangement, the mass consisting almost entirely of nuclei aggregated together. The thyroid of the human foetus just mentioned was of the same grayish aspect as that of the smallest of the embryonic sheep. It also consisted chiefly of nuclei, but these were to some extent collected together so as to form solid globular masses {Jig. 74.1.), not\nFig. 741.\nIncipient vesicle from thyroid of human f\u0153tus, at about mid-period. It is a solid mass of nuclei, not enclosed in a distinct envelope.\nyet, however, quite definitely isolated, nor surrounded by homogeneous envelopes. This, however, seems to be the way in which the vesicular cavities are developed ; the limitary envelopes being formed around the primitive nuclei, which assume the arrangement of epithelium. The thyroid is of larger relative magnitude during intra-uterine existence and infancy than in after life, \u2014 a fact which seems rather opposed to the view which regards this gland as alternating its action with that of the brain.\nComparative anatomy of thyroid.\u2014The existence of a thyroid gland in all the Mammalian orders seems to be undoubted ; and though it is probable that, by a close and extended survey of the various families, some interesting and perhaps instructive peculiarities might be detected, yet I have not the opportunities necessary for undertaking such an inquiry, and can only record one observation where some deviation from the ordinary condition was discovered. This was in a Rabbit, in which the organ presented the vesicular arrangement much less manifestly than is usually the case. The epithelium consisted of small imperfect celloid particles, disposed so as to form hollow spheres ; but there was scarce any appearance of secretion in the included cavities, which were small, and might at first have escaped observation.\nFor the following summary of the comparative anatomy of the thyroid in birds and reptiles, I am principally indebted to Mr. Simon\u2019s paper in the Philosophical Transactions.\nIn Birds, there are found, in all the various orders, two glands, situated one on each side of the trachea, very near the lower larynx, and frequently attached to the jugular veins. They possess the characteristic structure of the thyroid body, consisting of a dense aggregation of closed vesicles, which contain a kind of epithelium, and are invested by a close capillary network applied over their\nhomogeneous envelope. The position of these glands with respect to the larynx seems to be neither essential nor constant ; it is however stated by Mr. Simon, that it \u201c always corresponds to a particular spot of the vascular system, viz., that it lies on the cervical vessels, and receives its supply of blood just opposite to the point at which the vertebral or carotid arteries diverge to their respective destinations.\u201d\nThe following are the details of a microscopic examination which I made of these glands in a Pigeon. They consist of closed vesicles about\tinch diameter, having\ntheir homogeneous envelope lined by a rather thick layer of epithelium, so that the cavity is proportionably contracted, sometimes not being more than\tinch diameter The\nepithelium consists, for the most part, of nuclei and granular matter. Some of the nuclei are very perfect, and show a distinct vesicular structure, with a well marked peripheral nucleolus. Others are more like granules, solid and opaque, and not above half the size. Tim nuclei are imbedded in granular matter, which for the most part is diffused freely about, but occasionally, though very rarely, constitutes the contents of a cell. In some cavities the epithelium assumes the form of non-nucleated delicate vesicles, ofrath er large size {\u00dfg.1^2. b. ). No secretion, capable of being recognised by the eye, exists in the glandular cavities.\nFig. 742.\nFrom the thyroid of a Pigeon.\na, b, Two vesicles. The epithelium of a consists of nuclei and granular matter ; that of b of rather large, delicate, pellucid vesicles. The central cavity is small, especially in a.\nc,\tThe two varieties of nuclei, and \u2014\nd,\tA complete nucleated cell.\nReptiles.\u2014In the order Ckelonia the organ, which is demonstrated by the microscope to be really the thyroid, is found occupying a definite and uniform position. It lies in the median plane of the body, immediately above the base of the heart, between the two carotid arteries, a ndis overlapped and concealed by the pericardial lobes of the thymus. The structure of the gland in a young Tortoise I found extremely w ell marked ; the ve-","page":1108},{"file":"p1109.txt","language":"en","ocr_en":"1109\nTHYROID GLAND.\nsides were large, \u00abV toinch diameter, closely aggregated together, and very variously altered from the spherical form by mutual pressure. There was very little investing areolar tissue. The epithelium consisted of a single row of nuclei imbedded in granular matter, which was more abundant than usually is the case. In some parts this had almost disappeared, and was replaced by delicate vesicles larger than the nuclei which lay closely together in contact with each other. Whichever of these forms the epithelium assumed, it did not encroach much on the cavities of the vesicles, which were large and filled with some transparent non-refracting fluid.\nMost of the cavities also contained one to three yellowish coarsely granular globules, __i_ to in. diameter ; these existed in various stages of development. A fine large octohedral crystal was also seen in one of the cavities ; but there were no prisms of triple phosphate (\u00dfg. 743.).\nAmong the various families of the Saurians the thyroid is found to occupy different posi-\nFig, 743.\nOne side of a vesicle from thyroid of Tortoise.\nThe epithelial stratum consists of a single row of nuclei, imbedded in a more abundant quantity of granular matter than usual.\ntions ; in some being single and mesial, in others double ; in some it lies high in the neck, in others low. Even in the same family its arrangement is not always uniform ; thus among the Facertid\u0153 the gland is single, and of considerable breadth in the true lizards while in the Monitor it is double. Among the Jguanid\u0153, likewise, a similar variety prevails. The Gechotid\u00e6, Cham\u00e6leonid\u00e6, and Scincid\u00e6 present the same general form as the true lizard. In the Cham\u00e6leon it is rather higher (nearer the os hyoides) than in the other families, and is overhung by the sacciform dilatation of the larynx.\nIn the Amphisbania and Ophidia \u201cthegland lies just above the base of the heart, between the right and left carotid arteries. It is a little hidden by the thymus of each side ; and in those genera which possess a fat body this large organ lies conspicuously in front of both the thymus and thyroid.\u201d\nIn the Batrackian order there has been found, in the common Frog, on each side a small glandular body, which Mr. Simon declares is unquestionably possessed of true thyroid structure. They are situated on the carotid arteries, just beside the cornua of the hyoid bone. Huschk\u00e8 conceived these bodies to have their origin in the shrinking of the branchiae, and endeavoured to establish that the thyroid generally had its origin in the transformation of the branchial arches in the early embryo. This hypothesis, however, Mr. Simon well remarks, appears refuted by the existence of the gland in a perenni-branchiate\nanimal, the Menobranchus, where it consists of two symmetrical portions connected with the inferior border of the os hyoides, one on each side.\nIn the class of Fishes there seems yet some doubt whether a true thyroid gland really exists. Mr. Simon believes that he has discovered the organ in many fishes, enumerating the Carp (Cyprinus), Pike (Esox), Cod {Gadus), Haddock (Monhua), Whiting (Merlangus), Eel {Anguilla), Sturgeon {Accipenser), Shark {Squalus), and Skate (Raia); \u2014 it seems also to be present in the Anableps, Exoc\u0153tus, Cal-lorhynchus, and Lamprey (Petromyzon), but the evidence for its existence is less conclusive.\nIt may occupy, he states, either of three positions ; (l) as a single organ situated in the median line in connection with the basibran-chials, and supplied with blood from the first branchial vein while yet within the gills. (2) \u201c In the Gadid\u00e6 the gland is double. One portion lies on each side, not, as in the last case, at the anterior extremity of the first branchial arch, but near its posterior or vertebral end. Here it occupies part of a recess which is bounded by the gill below, and above by the outer extremity ofthat transverse fold of mucous membrane which limits the extent of the palate. It is merely covered by mucous membrane, which leaves it apparent to the eye without need of any express dissection. Its vascular supply is reflected to it from the ophthalmic artery, which arises before the formation of the systemic aorta from the first branchial vein close to the origin of the proper encephalic artery.\u201d (3) \u201c In the carp, anableps, pike, and exoc\u0153tus, the gland is placed at the inner extremity of the same duplicature of mucous membrane, and more toward the palate, so as to lie upon the fibres of the pterygoid muscle.\u201d Though there is this variety of situation, yet Mr. Simon regards these several organs as constantly agreeing in one point, viz., in deriving their vascular supply from the first branchial vein, and thus being brought into connection with the encephalic nervous centre,by their nutrient streams having origin from a common source. Professor Owen dissents from the view that the pseudobranchiae are the analogues of the thyroid gland. He states that in osseous fishes they are not diverticular to the cerebral circulation, but only to the ophthalmic, and in most cases are subsidiary, in this respect, to the choroid vaso-ganglion. The sublingual gland of Retzius is the organ which Professor Owen considers as most nearly representing the thyroid, though he suggests a doubt as to whether, by reason of its relations to the heart and great vessels, it may not more properly be regarded as the analogue of the thymus.\nIt is with some hesitation that I proceed to mention the results of my own examination of some specimens from the three classes pointed out by Mr. Simon, in which he seems to regard the presence of a thyroid as undoubtedly ascertained. I have, however, carefully examined the structure with the microscope in every instance, and I believe I may\n4 b 3","page":1109},{"file":"p1110.txt","language":"en","ocr_en":"1110\nTHYROID GLAND.\nrefer to the observations, so far as they go, as free from any material error. In the Skate I have found the organ described by Retzius as a salivary gland, and by Mr. Simon as a thyroid, occupying the situation well described by the latter, and lying exactly upon the terminal division of the branchial aorta. It was of a faint reddish gray tint, and presented to the unaided eye the appearance of a conglomerate gland. No excretory duct, however, was observed proceeding from it. In structure it consisted of numerous vesicles aggregated together. The form of these was mostly circular ; some were elongated, and many variously altered by mutual pressure. Their diameter was about to inch (fig. 744. A). The limiting envelope of the vesicles presented a\nFig. 744.\nFrom thyroid of Skate.\nA.\tVesicle, in. in diameter.\nB.\tSeveral of the nuclei imbedded in diffused mottled substance.\ngood example of homogeneous membrane. It was lined internally by a pretty thick stratum of epithelial substance, which in some instances was so abundant as almost to fill up the cavity. The epithelium consisted of nuclei and a very large quantity of rather coarse granular material, which quite obscured the nuclei themselves (fig. 744. B.) There were also a few granular cells, and, in the interior of many of the vesicles, imperfect prismatic or octohedral crystals could be discerned. I could not discover, among the glandular structure, any tubes resembling excretory ducts ; so that I am much inclined to believe it has no relation to the salivary organs, but belongs to the class of ductless glands. A gland, however, it assuredly is, and not a mere vaso-ganglion. Besides this body I discovered at some distance behind it, just at the junction of the branchial arches anteriorly, a small light reddish mass, which was covered in by a thin fascia, and by the mucous membrane, and could not be seen till the latter was dissected off. Its structure was almost exactly similar to * that of the organ just described, consisting of vesicles about\tto\tinch\ndiameter {fig. 745.), with a thick interior stratum of epithelium resting on a beautiful homogeneous limitary membrane. The pseu-\nFig. 745.\nA. vesicle from sublingual gland of Skate, diam. 9g in.\nIt contains abundance of nuclei and granular matter, with delicate vesicles.\ndobranchia, situated on the anterior wall of the spiracular canal, is manifestly of entirely different structure to the organs described. It consists of small plicae of mucous membrane, covered by a kind of pavement epithelium. In a Dog-fish (Spinax) the pseudobranchia was very small, but distinct. 1 could discover no trace of the sublingual gland, or of the small one behind it which I found in the skate.\nIn the cod and ivhiting the pseudobranchia is situated, as Mr. Simon has described it, near the upper extremity of the first branchial arch on each side. It lies in a recess which is bounded bv the gill below, and above by the outer extremity of that transverse fold of mucous membrane which limits the extent of the palate. Its structure is peculiar; Mr. Simon regards it as a thyroid ; but from this opinion I feel obliged to differ. The following description is taken from examination of the organ in the Cod, but applies equally to that in the Whiting. It is a body of light red colour, semi-transparent aspect, flattened so as to present two faces, about one line and a half in thickness, and having two borders, one convex and slightly notched, the other somewhat concave. ~ The surface is slightly uneven or nodulated. It is enclosed in a capsule, through which some large vessels are seen ramifying. Its general aspect is that of \u201c glandular flesh,\u201d and certainly not of a mere congeries of vessels. In structure it appears to consist of parallel folds of homogeneous membrane, beneath which is spread a vascular plexus, and which are covered by an unusually developed epithelium. This epithelium appears under the form of granular cells of an oval, circular, or irregular form, not distinctly nucleated, and having a diameter of\t*nch-\nThese do not appear to constitute a mere investment, but to form a layer of some thickness, filling up the intervals between the adjacent processes or folds of homogeneous membrane. These organs, manifestly constructed after the type of gills, evince thus a tendency to assume a glandular structure ; yet I can see no sufficient reason for supposing them to represent the thyroid, from which they differ so entirely in structural characters. In the whiting I could detect no trace of a sublingual gland, nor of the small posterior one; but in the Eel, where the","page":1110},{"file":"p1111.txt","language":"en","ocr_en":"THYROID GLAND.\t1111\npseudobranchia was absent, I found, by the aid of the microscope, between the first and second basibranchials, a small mass, which consisted in great part of fat, but contained also some large vesicles closely resembling those of a real thyroid. Their diameter varied from to inch. They had an homogeneous envelope lined by an epithelium, consisting of small non-nucleated pellucid corpuscles, and surrounding a cavity filled by a transparent somewhat refracting fluid.\nIn a Pleuronectid I found the pseudobranchia quite free, uncovered by mucous membrane, and projecting a series of small distinct leaflets into the branchial cavity. It differs essentially from that of the cod or whiting, and showed no tendency to assume a solid glandular form, but was manifestly a real though minute gill.\nIn a Carp I found the pseudobranchia with some difficulty. It was situated very deeply between the anterior part of the upper extremity of the first branchial arch, and the posterior border of the pterygoid muscle. Its structure was entirely that of a gill, consisting of parallel folds of a membrane, arranged transversely to a median axis, and overlaying a vascular plexus. These folds were covered with a kind of scaly epithelium, which was often detached in large pieces, and mingled with some circular cells, closely resembling mucous globules. I could find no trace of the sublingual nor of other adjacent gland.\nFrom the few facts now detailed I think it may be concluded, ( 1) That there is no evidence from their structural characters to prove that the pseudobranchiae are the representative of the thyroid. (2) That in some instances organs which seem to be of a totally different kind are found, which resemble very closely the structure of the thyroid when it unquestionably exists. Mr. Simon lays stress upon the circumstance, that the pseudobranchiae and the sublingual gland receive their vascular supply from the same source, viz. the 1st branchial vein ; this, however, is not constantly the case, the pseudobranchiae in osseous fishes, according to Professor Owen, serving only as diverticula to the ophthalmic, and not to the cerebral circulation; so that on this ground they cannot be supposed to have similar functions. For a philosophical discussion, however, of the analogy and homology of the pseudobranchia to the thyroid, I wfould refer to Professor Owen\u2019s Lectures, vol. ii. p. 270. note.\nMorphology. \u2014 The preceding details are abundantly sufficient to prove the glandular nature of the thyroid. This truth, which elder anatomists saw clearly, though rather afar off, we, by more intimate and minute scrutiny, are enabled to confirm and establish in every particular. Let us take in order the several parts of the secretory apparatus of the thyroid as we have described them, and see whether they do not exactly correspond to homologous parts in any undoubted gland. The recep-tacular cavities, enclosed by envelopes of homogeneous membrane, manifestly represent\nthe tubes of the kidney or testis, or the terminal vesicles of the salivary gland. The limitary tissue is identical in appearance in each ; but disposed in the one so as to form shut sacs ; in the others to ensure a pervious canal or outlet, for the secretion. In the true glands the limitary tissue or basement membrane supports, on its interior, a layer of epithelium, essentially consisting of nuclei and granular matter. The same tissue in the thyroid is lined internally by a similar layer, which differs only in the smaller quantity of granular matter interposed among the nuclei, and in both cases the formation of perfect cells (i. e. with envelopes) is uncommon. The exterior of the limitary tissue is in contact, in all the true glands, with a capillary plexus, from which the materials for the nutrition and growth of the epithelium are furnished. The same disposition exists in the thyroid. A certain amount of fibrous tissue, or some modification of it, penetrates more or less extensively among the elementary parts of the true glands, and serves to pack and unite their component parts together ; this also we have had occasion to describe in the thyroid. With respect to a supply of lymphatic vessels and nerves, it is sufficient to state, that as far as ordinary dissection can go, the thyroid is similarly circumstanced with the other glands ; and there is no reason to doubt that the actual arrangement of these parts in all is the same. The parallel, thus exactly sustained in every particular, warrants us in regarding the thyroid as the nrapaSsiypa of the class of ductless glands, and it may be not without advantage, if we take occasion to note, in the other organs belonging to the same class, how gradually the strongly marked characters are laid aside, till the glandiform organ passes into a modification of vascular structure. In the supra-renal capsules the limitary membrane, though described by an eminent anatomist as usually forming tubes of various length, enclosing celloid epithelial particles, is, according to my observation (which is however but limited), very faint, or entirely absent. I have never been able to discover it in the human adult or foetal subject ; and in the sheep the cortical structure has seemed to consist simply of rows of celloid nucleated particles, without any enclosing membrane. Conceding, however, that in these organs the limitary tissue does exist,, there can be no doubt that it is much more feebly developed than in the thyroid, while, as a set off, the epithelial particles are more perfectly formed. In the case of the thymus the limitary tissue is well marked, and resembles very much, in its arrangement, that of the conglomerate salivary gland ; but the epithelium is remarkably modified. The nuclei exist, but almost alone. No granular matter of any peculiar properties is formed around them, preparative to, and evidencing the existence of, secretory action. In the spleen both these alterations coincide. The epithelium is reduced to mere nuclei aggregated in masses round, prodigiously developed venous radicles, and\n4 b 4","page":1111},{"file":"p1112.txt","language":"en","ocr_en":"1112\nTHYROID GLAND.\nthe limitary tissue is discoverable nowhere, not even surrounding those curious spherical masses of nuclei the white corpuscles of Malpighi. The only circumstance I know of, which seems to indicate that even in the spleen a kind of secretory action does occasionally take place, is, that there frequently occur, in the parenchyma, some peculiar yellow corpuscles, which are most abundant in fishes, and of which I gave a detailed account some years ago. The very presence, however, of these (for they are by no means constant), as well as their condition, argue strongly that secretion is not the appointed function of the splenic parenchyma. From this, the last and lowest of the ductless glands, we descend to erectile tissue, in which the venous portion of the sanguiferous system is even more highly developed than in the spleen, and where the intervening parenchyma is still further reduced in quantity; yet, from the phenomenon of afflux of blood to the part, it must be regarded, I think, as exerting an attractive force, as is unquestionably the case in the spleen.*\nReturning from this digression to the consideration of the thyroid, we may lay it down as fully established, that it is a gland whose secretion is formed, and collects, in closed cavities. Now from this fact we are able easily to deduce another, viz., that the secre*-tion when formed is capable of being absorbed from the receptacular cavities ; for otherwise these would go on enlarging and distending themselves indefinitely, as in fact they do under certain morbid conditions. But, though there may be various causes concerned in the production of bronchocele, yet I think it must be regarded as proved, by Mr. M'Clellan\u2019s inquiries, that certain waters are adequate of themselves to produce this disease ;\u2014it would appear that when they are drunk, some ingredient or principle is supplied to the blood, which, being in excess, is straightway elimi-mated by the epithelium of the glandular cavities of the thyroid, and thus collects in, and distends them. If a patient in whom this has occurred be removed from using this unwholesome water, and if the natural absorbing power be aided by the influence of iodine, then, the supply of the substance for which the thyroid has a special attraction being cut off, the excess collected in the receptacular cavities returns speedily to the circulating current, which now, being in a minus condition as to this principle, readily resumes it. In such cases there seems, in fact, to take place a very analogous process to that which occurs in ordinary fattening and emaciation ; if an excess of oily matter exist in the blood, old fat vesicles enlarge, and new ones are formed ; if the reverse is the\n* The well marked variation in size of the spleen at different times proves, I think beyond doubt, that it exerts an actively attracting force on the blood which traverses it ; else what possible reason can be given for its containing much more blood at one time than at another ? No contractile tissue exists here which can be supposed to obstruct the returning current by the splenic vein.\ncase, the oil in the fat cells is readily absorbed into the blood circulating in the capillary loops around them.\nThe condition in which the epithelium of the thyroideal cavities is usually found is worth observing, and seems susceptible of a probable interpretation. It may be stated as \u2022 a pretty well established fact, that the nucleus j of a cell is the essential part, that in it resides that influence, or is developed that force, which produces all the phenomena of growth and assimilation ; that, so long as the nucleus persists, the energy of the cell, if one has been formed, continues to be manifested ; but, if it has disappeared, the active life of the cell is at an end. It is also certain that the completion of a cell, i.e. its being surrounded by an envelope, is by no means an essential circumstance ; that all the purposes of cell life may be effected by the mere aggregation of granular matter around a nucleus ; that, in fact, the cell wall or envelope is of no importance, or but very little, in the metabolic changes which are produced, and that its presence, when it exists, seems merely to denote a certain permanence of duration in the particle. Many ={ examples of the correctness of these statements, will occur to every one who is in the habit of examining the glandular organs in man or the lower animals. I believe we may also advance a step beyond these doctrines, and regard it as very probable that, when we find an epithelial structure consisting principally of bare nuclei, with but a scanty interposed quantity of granular matter, the secreting action there effected is of a rapid and simple kind ; the destined product being quickly formed and thrown off, and not slowly evolved within the chamber of a cell. The following instances may be referred to, as illustrating the extreme varieties of secretory action in reference to this particular. The cells in which the spermatozoa are formed must be of considerable permanence, the development of the filaments taking place gradually, and in one instance, as Mr. Goodsir has shown, only being completed in the spermatheca of the female. The biliary cells of various annelida are at first filled with pale granular contents ; but gradually these are replaced by the characteristic molecules with which the cell becomes at last distended, and thus remains, often for a long time. The cells of the kidney of the common snail, which are very perfectly formed, enclose, within a well marked envelope, an opaque white mass of uric acid, which, after a long time, may increase to such a degree as completely to fill the cell. These cells are very permanent.*\nIn contrast to these instances, wherein complex and elaborate products are formed in complete cells by a secretory action of a slow and deliberate character, we may refer to (1)\n* I preserved some snails in a box for about a year\u2014they remained in a perfectly torpid state, and took no food. The renal cells at the end of that time were almost all fully distended with uric acid, while usually they are not more than half full.","page":1112},{"file":"p1113.txt","language":"en","ocr_en":"THYROID GLAND.\t1113\nthe absorbent glands, which doubtless produce some change in the fluid which traverses them ; this, however, must necessarily be a rapid process, and, accordingly, scarce any cells are formed; the mass of the glandular parenchyma consisting of very perfect nuclei; (2), the terminal hepatic ducts, whose walls, as I have shown, consist almost entirely of nuclei set close together, and which, by means of these effective agents, eliminate the actual biliary secretion from the varying, partly biliary, partly oily, fluid formed by the hepatic cells on their exterior ; this process of elimination is, I believe, continually going on, and is not so much of a metabolic as of an absorbing nature ; the essential change being probably effected by the hepatic cells of the lobules; (3) the nucleated tissue forming the principal part of the villi, which scarce ever developes cells,* but is constantly attracting the chylous fluid through the basement membrane from the cavity of the gut, and permitting it to pass off by the efferent lacteals (here scarce any chemical change appears to take place) ; (4) the cineritious matter of the cerebral hemispheres, which, amid the rapid alternations of sensation, thought, and volition, must be undergoing incessant change, consists, in by far the greater part, of nuclei and granular matter, the fully formed vesicles being few and far between.\nApplying, now, these views to the case of the thyroid, there seems reason to believe that the ordinary condition of its epithelium is such as to adapt it for rapid and transitory action ; so. that a large amount of secretion maybe quickly thrown into its cavities on any sudden occasion ; which again would easily transude through the thin epithelial layer and homogeneous tunic, when the time of action had passed by.\nIt may also be remarked, as consonant with the views above stated, that as respects its chemical nature the secretion of the thy-roideal cavities is of a simple kind, not apparently requiring much elaboration. It seems, in fact, to be a mere modification of albuminous matter containing, it may be, some gelatine, but strongly contrasting with the highly wrought products of the renal and hepatic laboratories. This implies that the change effected by the thyroideal epithelium on the liquor sanguinis supplied to it is by no means considerable.\nUse.\u2014 Cruveilhier, writing about fifteen years ago, briefly says, \u201c the use of the secretion of the thyroid is unknown ; \u201d nor can the anatomist of the present day give a much more satisfactory account. So enveloped in mystery the use of the gland seems to have been always regarded, that inquirers have been more willing simply to confess their ignorance than is usually the case, and fewer speculations and hypotheses have been broached respecting this than regarding other points which promised at first sight to be of easier solution. It is scarcely worth while\n* I venture herein to differ from Professor Good-sir, not without repeated and careful observations.\nto mention the opinion, which supposes the thyroid to have any essential connexion with the larynx, either as pouring into it, through supposed ducts, a fluid fitted to lubricate the lining membrane, or, as Sir A. Carlisle supposed, forming a protection to the delicate organs of the voice, against the variations in temperature of the external air. There seems no doubt that the relative position of the thyroid to the larynx is quite unimportant, so far as the function of the organ is concerned. This is borne out by the variations of its site which occur in birds, and by the results of morbid action ; since prodigious goitre does not induce disease of the larynx, except in a mechanical way, i. e. by injurious pressure.\nPassing over more crude conceptions, we come to consider a theory which has been propounded by Mr. Simon, and which has certainly every claim to our careful attention, both from the character of its author, and as it is the only one yet promulgated which can be said to be even probable. He considers that the thyroid acts as a diverticulum to the cerebral circulation ; exercising, aFthe same time, its secretory function in an alternating manner with the encephalic nervous mass. His words are, \u201c What diversion is to the stream of blood viewed quantitatively, alternative secretion would be to the composition of blood viewed qualitatively ; and I should conceive that the use of the thyroid gland, in its highest development, may depend on the joint exercise of these two analogous functions. I should suspect not only that the thyroid receives, under certain circumstances, a large share of the blood which would otherwise have supplied the brain, but also that the secretion of the former organ bears some essential relation (which chemistry may hereafter elucidate) to the specific nutrition of the latter ; that the gland,\u2014whether or not it appropriates its elements in the same proximate combination as the brain does,\u2014may, at all events, affect, in a precisely similar degree, the chemical constitution of the blood traversing it ; so that the respective contents of the thyroid and cerebral veins would present exactly similar alterations from the characters of aortic blood. Finally, I should suppose that these actions occur only, or chiefly, during the quiescence of the brain, and that when this organ resumes its activity the thyroid may probably render up again from its vesicles to the blood, in a still applicable form, those materials which it had previously diverted from their destination.\u201d\nThis theory mainly rests on the circumstance that the thyroideal arteries arise in close proximity to the cerebral, and this is I think sufficiently constantly the case to form a strong argument in its favour. It must be remembered, however, that variations in the place of origin of the arteries both of the brain and thyroid, do occur without, as far as we know, any interference with the full discharge of the functions of the gland ; and it may also be considered probable that the purpose of a diverticular stream would have been better","page":1113},{"file":"p1114.txt","language":"en","ocr_en":"1114\tTHYROID GLAND.\nattained, if the origin of the vessels had been below instead of above the point of giving off of the arteries to the brain. Besides, however, this argument, two others may be mentioned which at least favour the same view. One is, that no special characteristic principle appears to exist in the secretion of the thyroid, but that it is a mere modification of albuminous matter,\u2014this seeming to imply that no special use is served by the secretion of the gland, that it is not elaborated for the sake of producing any peculiar effect on some other part, but that it is simply secerned from the circulating current for a time, to return and mingle with it again in a condition but little altered from its primitive one of blood-plasma. The other argument is drawn from the condition of the epithelium, which, as we have before remarked, seems adapted for rapid and transitory action, so that it might quickly secrete a large amount of material on any diminution of the nutrient processes in the brain. These arguments may be allowed to possess some weight. Before, however, this theory can be' regarded as at all established, a more sure and discriminating chemistry must prove some relation of composition to exist between the secretion of the thyroid and the grey nervous matter. Till this is done we can but deal with the question afar off, without bringing it to an exact issue.\nMorbid Anatomy.\u2014The following morbid changes have been observed to occur in the thyroid; (1) It maybe affected with common inflammation. (2) It may be variously altered by unhealthy or perverted action of its own glandular structure. (3) It may be the seat of adventitious formations. (4) Its vessels may become remarkably enlarged, as in the so called aneurism by anastomosis.\nInflammation. \u2014 Professor Hasse gives the following description of inflammation occurring in the thyroid. \u201c It is rare, but may attack the organ either when healthy, or when enlarged by previous disease. Its course is more frequently chronic than acute. Within a very brief interval the gland often swells considerably, becomes very bloodshot, tense, and painful, its texture softened and friable, assuming at first a brown red, and ultimately a dingy gray colour. The morbid anatomy of this grade of inflammation is but imperfectly known ; that of the suppurative stage has been more frequently observed, and more fully described. Either separate abscesses form, or else the entire gland is converted into pus. Under favourable circumstances the abscess opens externally through the skin. There are, however, examples of its obtaining vent through the oesophagus, and determining a protracted fistula of the gullet,* or of its discharging itself into the trachea, and producing death by suffocation.f After evacuation of the pus, together with numerous shreds of dead cellular tissue, the tumour collapses ; the gland on the\n* Unger, Beitrage zur Klinik der Chirurg, vol. i.\nf Meckel.\nside affected shrivels into a hard, cellulo-filamentous knot, which adheres firmly to the skin and to the surrounding parts. Sometimes the shrivelling of the one gradually brings on wasting of the other lobe.\u201d\nAlterations of Structure. \u2014 Under the second head may be included hypertrophy of the thyroid, or some enlargement without appreciable change of texture. This variety,\u201d Prof. Hasse states, \u201c is frequent, and for the most part inconsiderable.\u201d It probably depends merely on distension of the glandular cavities by their accumulated secretion. This change is almost wholly \u201c confined to youth, and is frequent about the age of puberty in both sexes,\u2014 more so, however, in the female.\u201d \u201c Alternatives of increase and decrease are especially apparent in this kind of bronchocele, enlargement being most conspicuous at the approach of the menstrual period.\u201d This form, though it may be called hypertrophy, is not quite strictly so designated, as there is no formation of new glandular tissue, but only distension of the original cavities, by an increased quantity of secretion.\n\u201c Melicerous degeneration of the thyroid is one of the most frequent forms. It occurs at all ages, and is uniformly attended with intumescence. It may involve the organ in whole or in part. In the former case the component granules (or vesicles) are found unusually and unequally enlarged, and transformed into separate cells filled with a tenacious, viscous,jelly-like substance, of the colour of honey. The entire part is hard, nearly bloodless, and but loosely coherent with the surrounding parts. Where, as frequently happens, only certain portions are disorganized, these form spherical tumours varying in size, and imbedded clearly in the healthy structure. They present a brownish or yellow colour, and the consistency of jelly or of melted glue. Sometimes they appear as an opaque, reddish, soft, or even lardaceous, swelling. In general but few blood vessels are visible in this goitre,although it may now and then be associated with exuberant vascular growth.\u201d\nThe foregoing description is quoted from the translation by the Sydenham Society of Professor Hasse\u2019s work. He does not, however, seem to notice sufficiently, under this head, the variety of matters which are found in the enlarged glandular cavities. Cretaceous matter, either in a pulverulent state, or forming hard ossiform masses, I believe often occurs, and in Prep. 1498, of the Pathological collection in the Museum of the College of Surgeons, there is seen a quantity of solid white substance, either opaque and soft, or transparent, firm and chondroid, which occupies the larger cavities, the majority being filled with a transparent jelly-like material ; some also with cretaceous matter. One interesting instance, probably belonging to this class, is quoted in the Cyclop, of Pract. Medicine from De H\u00e4en:\u2014\u201c In cadavere horren-dam mole thyroideam nactus, public\u00e8 dissecui. Mecum auditores mirabantur, nullum feregenus tumorum dari, quin in h\u00e2c sol\u00e2 thyroide\u00e2 in-","page":1114},{"file":"p1115.txt","language":"en","ocr_en":"1115\nTHYROID\nvfeniretur. Hic enim steatoma, ibi atheroma, alio in loco purulentus tumor, in alio hyda-trius, in alio erat coagulatus sanguis, fluidus fere in alio, imo hinc glutine loculus plenus erat, alibi calce cum sebo mista.\u201d\nI may mention here the results of microscopic examination of a specimen of this form of enlarged thyroid, for the opportunity of making which I am indebted to the kindness of the medical officers of St. George\u2019s Hospital. The gland was greatly enlarged ; its surface somewhat nodulated. A section displayed a number of cavities visible to the naked eye, some of which were circular, others elongated, and as it were compressed. Many of them were about the size of a large pin\u2019s head; some however, much more capacious. The majority were filled with a slightly opaque, firm, gelatinous material ; but some (the larger) with cretaceous or ossiform matter, and some also with a reddish material. The intervening structure in several places appeared tolerably natural ; but even in this, on close inspection, enlarged vesicles were perceptible. The areolar tissue separating the lobes of the gland was hypertrophied, and formed whitish septal bands. Under the microscope it was seen that the vesicles were generally enlarged. They were found of all sizes, from those that were distinctly visible to the naked eye, or still larger, down to the natural size. Their walls were somewhat but not uniformly or very greatly thickened. The homogeneous envelopes presented, generally, somewhat of a fibrous appearance. The greater number of the cavities were distended with a transparent, feebly refracting, structureless, material, in which were numerous small irregularly shaped particles of higher refracting power. This material resembled, almost exactly, the normal secretion in appearance, and, like it, was free in the cavity of the vesicles. In these vesicles there was very little trace of epithelium, only some small, and few, non-nucleated corpuscles ; but in other vesicles the epithelium was so abundant, that it completely occupied the cavity. It was in no respect different, except as to quantity, from its healthy condition, consisting of mere nuclei and interposed granular matter in no great abundance. In some of the vesicles there were large and beautiful crystals of more or less perfect octohedral form. These were either oxalate of lime or triple phosphate. One prodigiously enlarged vesicle contained a mass of calcareous matter, very firm and dense throughout, but most in its central and peripheral parts. In the latter situation there were numerous masses of ossiform substance, of yellowish semi-transparent aspect. On crushing these, no bone lacunae could be discerned in the fragments. They dissolved freely with strong effervescence in nitric acid, leaving an homogeneo-fibrous basis substance, which often exhibited a greenish yellow tint. The material, thus proved to be of cretaceous nature, contained, mingled with it, numerous tablets of cholesterine. One small reddish mass, occupying the cavity of a vesicle, was found to consist almost wholly of blood\nGLAND.\nglobules and their detritus, and thus seemed to be the result of haemorrhage. Another opaque whitish mass did not effervesce with nitric acid, and was therefore not cretaceous ; it consisted of epithelial nuclei mingled with peculiar, and rather abundant, granular matter. In the above account it is worth noticing that no cells were found ; the epithelium retained its natural appearance ; also the matter distending the greater number of the cavities resembled exactly, so far as the eye could judge, the natural secretion ; and lastly, that in some instances there was an accumulation of unaltered epithelium and not of the secretion. This last fact is of some importance with respect to the exact nature of the function discharged by the epithelium.\nOwing to the kindness of my friend, Mr. H. Gray, 1 have recently had the opportunity of examining a remarkable specimen of Bronchoc\u00e8le. The gland was greatly enlarged,\u2014to five or six times its natural magnitude,\u2014 and altered in form, one lateral lobe being raised up higher than the other, and the surface being somewhat uneven and nodulated. On a section being made, the exposed surface presented a reddish glossy aspect, somewhat resembling that of certain forms of malignant disease which are undergoing softening : there was no appearance of distended cavities ; in fact, the structure to the eye exhibited less of the cellular arrangement than is usual. Microscopic examination confirmed the impression derived from simple inspection. \u2014 But little of the natural secreting structure remained, the vesicles being destroyed, and their secretion, though still present in some quantity, being certainly diminished. Some traces of the epithelium of the cavities were perceptible; but there was no special cell growth indicative of any adventitious formation ; a few large cells or globules only, varying in size from\ni-- to xsVo diameter, existed in some of\u00b0the remaining cavities: these evidently consisted of aggregations of oily molecules and drops not manifestly enclosed by any envelope. The blood-vessels were prodigiously and universally enlarged ; some of those which were capillaries in structure were from two to three times their normal diameter, and irregularly dilated and varicose ; they were every where clustered over with minute oil drops ; which formed so thick a coating to many of them, that they appeared as white cylinders by direct light. Some parts of the gland presented to the naked eye a whiter aspect than others ; and in them it was seen that the deposit of oily matter along the vessels, and the destruction* of the glandular tissue, had proceeded to the greatest extent. In some places there were masses of ossiform deposit.\nThe morbid alteration now described approaches most nearly, I think, to the vascular and aneurismatic bronchocele ; but the extensive destruction of the glandular tissue, and the copious deposit of oily matter, show that there must have been some grave derangement of the nutrition of the gland. The case occurred in a female (\u00e6t. 75.), who died with","page":1115},{"file":"p1116.txt","language":"en","ocr_en":"1116\tTHYROID GLAND.\ncirrhosis of the liver and ascites ; the kidneys contained numerous small cysts, and there were two fibrinous blocks in the spleen.\nAdventitious formations. \u2014 Cystic formation within the thyroid is next described by Professor Hasse ; and regarding it as depending on the development of new cysts within the gland, and not on the perverted or excessive action of its own natural vesicular cavities, it will fall under our third head. I am, however, rather in doubt whether most cases of cystic formation in the thyroid do not belong to the second category, and are not dependent on the development of any adventitious structure. Prof. Hasse says, \u201c cystic formation within the thyroid gland is one of the most frequent causes of goitre. It occurs both by itself, and in conjunction with other kinds of degeneration, and constitutes the largest and most unsightly of all tumours. Cysts of every variety and size, either solitary or in congeries, are encountered in every part of the thyroid gland ; an entire lobe, nay, the greater portion of the whole organ, being sometimes engaged in cystic development. The surrounding texture is seldom healthy, being generally .compressed, flabby, and bloodless. The cysts are, for the most part, isolated. Occasionally, however, they abut one upon another, so as to form a single multilocular capsule. Here, as elsewhere, they are composed of two membranes ; namely, an external filamentous, and an inner serous, one. The external membrane is either smooth, or sends forth bands which attach it closely to the rest of the texture ; in many instances it partially, if not wholly, ossifies. The sac contains a limpid fluid, or a number of secondary hydatids *, or, again, a jelly-like substance, but more commonly a yellowish or whitish crystalline pulp, consisting almost wholly of cholesterine crystals with phosphate and carbonate of lime. In some instances the cyst accidentally inflames and becomes atrophied ; in others it gradually fills with earthy matter, and is transformed into a hard calcareous nodule. Cysts occur in the thyroid gland, in both sexes, and nearly at all ages ; more frequently, however, in females after the prime of life.\u201d A remarkable case of cystic formation in the thyroid is mentioned by Andral. He states that the whole organ was converted into a cyst with bony walls filled with a honey-like fluid. He seems to recognise both the cystic and melicerous degeneration as further stages of the perverted or excessive action which occurs in simple hypertrophy, and justly refers to the case of the ovary as exactly analogous, the cysts of which, filled with various products, originate, in all probability, in Graafian vesicles, which undergo an abnormal development.\nProf. Hasse has never met with tubercles occurring in the thyroid. Prof. Louis makes no mention of such an occurrence, nor does M. Papavoine in a table which he gives of\n* Lieutaud mentions a case where the trachea was perforated by one of these acephalo-cysts.\nthe seat of tubercle in various degrees, drawn up from the examination of the bodies of fifty children.\nSauten has observed that persons affected with extensive bronchocele seldom or never become subjects of phthisis.\nCarcinomatous growths rarely affect the thyroid. Eight cases in 8289 of deaths occurring from cancer in Paris, are ascribed to this part. * The disease is sometimes primary, sometimes secondary, or the result of invasion from some neighbouring affected part.\nEncephaloid or scirrhus in several of their varieties have been known to occur in the organ, but no example of colloid in it has yet been detected : of course cysts filled with melicerous contents must not be confounded with the loculi of real colloid, to which they bear some resemblance. Primary cancer in the thyroid usually exhibits the characters of scirrhus, secondary those of encephaloid : in the first case the disease is usually infiltrated, in the second of the tuberous form. Encephaloid here, as elsewhere, often grows rapidly, and attains a large size. It seems to obliterate entirely the natural appearance of the gland. It is often of the h\u0153matoid variety, in which there is sometimes softening in the centre of the mass, causing rupture of vessels and extravasation of blood. Occasionally black pigment is accumulated within its texture in varying amount, \u201c Medullary cancer of this gland must not be confounded with that of the lymphatic glands of the neck, which often simulates goitre.\u201d\n_ Enlargement of the Vessels. \u2014 The last kind of morbid degeneration, which the thyroid has been observed to undergo, is that to which the term vascular or aneurismatic bronchocele has been applied. It is described as follows by Professor Hasse,\u2014\u201c All the blood vessels are much amplified, the veins in particular forming very dense, capacious, often knotted, plexuses, and the whole texture consisting apparently of a dense coil of vessels. The substance of the gland has almost entirely lost its granular character ; it is flabby and dark red. After death the tumour collapses considerably, and can only be restored to its original size by artificial injection. The walls of the arteries and veins are attenuated, the dilated membranes of the vessels contain considerable clots, and capacious cavities are found filled with black coagulated blood. Vascular bronchocele affects the entire gland; principally, however, one or other lobe. It occurs most frequently in females after the prime of life, and is, like simple hypertrophy, marked by periodical augmentation and decrease. This general dilatation of blood-vessels must not be confounded with the exuberant vascular (malignant) growth termed fungus h\u00e6matodes, to which the thyroid gland is also subject.\u201d In the foregoing description we have clearly set forth the condition of an organ, the walls of whose vessels have, from loss of their natural tonicity, yielded to the\n* Walshe on cancer.","page":1116},{"file":"p1117.txt","language":"en","ocr_en":"THYROID GLAND.\t1117\nimpetus of the current of blood, and being thus enlarged and distended, have pressed upon the essential structure of the gland, and caused it to become atrophied.\nIt may not be amiss to observe, after this review, that the disease of the thyroid, which is of by far the most frequent occurrence, viz. enlargement of its magnitude from excessive or perverted secretory action, is just of the kind we should, from our knowledge of its actual structure, expect would be most liable to occur. For when once the nicely arranged balance of secretion and absorption, with its moderate alternating oscillations in either direction, is permanently deranged, the closed cavities of the glandular vesicles afford no exit to the accumulating matters. Thus does minute anatomy explain, and thus is it confirmed by, the changes wrought by disease.\nHistory of Investigations. \u2014 The following is not presented as a complete history of the thyroid, but as a sketch which it is hoped contains the principal facts relative to the advance of our knowledge respecting it.\nIn examining the works of Aristotle, I find he makes no mention of the thyroid in two places, where he describes the organs situated in the neck, and speaks especially of the trachea. Galen does not give any very distinct account of the thyroid, so far as I have been able to discover ; but certainly seems to allude to it in a passage in his book \u201c On the Use of the Parts of the Human Body,\u201d where he speaks of the glands of the larynx, \u201c which are always found more loose and spongy than others, and which, by the common consent of anatomists have been created for the purpose of moistening and bathing all the parts of the larynx and the passage of the throat.\u201d The following passage, quoted also in a note by Morgagni *, seems to prove that he was aware of the main peculiarity of the thyroid. \u201c Now the neck has two glands, in which a moisture is generated. But from the two glands which are in the neck there come forth no vessels by which the moisture may flow out, as those do from the glands of the tongue.\u201d Vesalius, who wrote about a.d. 1542, distinctly recognises the existence of the thyroid in the following passage from his work, \u201c De corporis humani fabric\u00e2.\u201d f \u201cAnd this dissection also shows two glands, adhering one on each side, to the root of the larynx, which are of large size, and very fungous, and nearly of the colour of flesh, but darker, and covered over with very conspicuous vessels.\u201d In the second book he describes their appearance in oxen, in whom they resemble muscular tissue, he says, very much, while in man their aspect is more truly glandular. Jacobus Sylvius, who wrote a little later than Yesalius, enumerates, in his list of glands, \u201c du\u00e6 item ad laryngis radicem asper\u00e6que arteri\u00e6 initium utrinque una qu\u00e6 interdum ob magnitudinem in unam abire videntur.\u201d Wharton, in his Adenographia, published about 1656, gives a very full and good description of the thyroid ; he notices\n* Advers. Anat. i. c. 26.\tf Lib. vi. cap. 4.\nits situation, figure, magnitude, texture (sub-stantiam), and consistence (soliditatem) ; and remarks \u201c that it is much more full of blood than any other gland, also more viscid and solid, and more resembling muscular flesh. This is the only difference, that it is not of a fibrous structure, but rather of a glutinous nature.\u201d He assigns four uses to the gland, which it may be worth while to quote, as affording an example of the speculations then in vogue, the last perhaps being not the least real and important of those he mentions !\t\u201c (l) The\nfirst and principal use of these glands appears to be to take up certain superfluous moistures from the recurrent nerve, and to bring them back again into the vascular system by their own lymph channels. (2) To cherish the cartilages to which it is fixed, which are rather of a chilly nature, by its own heat ; for it is copiously supplied with arteries, and abounds with blood, from whence it may conveniently impart heat to the neighbouring parts. (3) To conduce by its exhalations to the lubrication of the larynx, and so to render the voice smoother, more melodious, and sweeter. (4) To contribute much to the rounded contour and beauty of the neck; for they fill up the empty spaces about the larynx, and make its protuberant parts almost to subside and become smooth, especially in the female sex, to whom on this account a larger gland has been assigned, which renders their necks more even and beautiful.\u201d\nVerheyen, writing about 1720, describes the thyroid as deriving its name from the cartilage so called, and states that it is considered by some as double, i.e. consisting of two glands. He says, \u201cthis gland, beyond doubt, serves also to moisten the neighbouring parts ; but, because it is very large, there is an apparent reason why it should have rather large excretory ducts, or one at least very conspicuous, which yet hitherto has not been discovered.\u201d\nAbout 1708, Evertzen wrote an inaugural dissertation on the thyroid gland, noticing its structure, some diseases to which it is liable, and their treatment.\nMorgagni, in his Advers. Anat. (1723) discusses two questions respecting the thyroid ; one as to whether the gland is double or single, i. e. whether the lobes are connected by an isthmus or not ; this he decides, as respects man, positively in the affirmative. The other vexata questio, as to whether the thyroid be provided with a duct or not, he confesses to be yet undetermined. He notices the existence of vesicular cavities in enlarged thyroids, which he justly supposes to be the natural cavities (nativi acini) dilated by their accumulated secretion. From his examination of the secretion of the thyroid, \u201c mollem quendam, et obliniendo lubricandoque ido-neum, suceum communi isti amygdalarum oleo long\u00e9 consimilem and from observing the thyroid to be exposed to the pressure of contracting muscles, as is the case with some other undoubted glands, he inclines to consider it probable that the gland has some duct","page":1117},{"file":"p1118.txt","language":"en","ocr_en":"1118\nTHYROID GLAND.\nopening into the pharynx, the oesophagus, or into the top of the trachea.\nSantorini (Observ. Anat. 1754), recognizes the thyroid as a single gland, and makes mention of its median column as previously known to Morgagni, though it was probably discovered by Bidloo or Lalonette. He details the failure of his efforts to discover a duct, though he had several times detected an orifice at the anterior angle of the glottis, into which a bristle could be passed ; and yet remarks that the thyroid gland may be urged to expel its secretion by the pressure of the sub-hyoidean muscles, the throbbings of the carotids, and the contractions of the oesophagus.\nHaller (Element. Physiolog. 1766), in his account of the thyroid, gives a good description of the median column, and of the several varieties which it presents ; four times only has he found it absent ; most frequently existing on the left side ; sometimes, however, on the right. He relates some experiments of Lalonette, in which it appeared as if the glandular cavities had been distended by inflation with air, and also the lymphatic vessels proceeding from them. The result of this coarse proceeding he explains, and probably correctly, by supposing that the distended cavities were those of the areolar texture, and not the secreting vesicles. He remarks that, even according to Lalonette\u2019s testimony, no secretion can ever be pressed out of the thyroid gland into the cavity of the larynx ; or if any appear it seems to be nothing more than the contents of some mucous follicles. After detailing the struggles and efforts of various anatomists to discover an efferent duct, he states at last that several inquirers, among whom he mentions Ruysch in particular, had adopted the only possible remaining opinion, that a peculiar fluid was elaborated in the gland, which being received into the radicles of the veins, was returned into the blood. This view, which laborious, and thoughtful, and sagacious men were then slow to entertain, is now universally adopted ; and it seems certainly a matter of wonder that it was not sooner arrived at. May we not, however, question whether, in regard to other glands, a process somewhat similar does not also occur, \u2014whether certain complementary products of secretory action are not formed in the gland, and afterwards absorbed and carried off' by venous and lymphatic radicles?\nMeckel\u2019s description of the thyroid is as complete as could be accomplished by the most consummate anatomical skill, while unaided by the achromatic lens. I need not refer to his well known pages, further than to notice a suggestion which he offers, viz., that as the median column is much more developed in the infant than in the adult, the excretory duct may exist at that period (in the median column), and become obliterated as age advances.\nIn proceeding beyond this period, we come to the anatomists of our own day ; several of whom have advanced our knowledge con-\nsiderably respecting the thyroid and other ductless glands. To none, however, are we ! more indebted than to Mr. Simon ; whose ! masterly and philosophical Essay on the ? Thymus contains the best account of the anatomy and physiology of these organs that has yet been given.\tJ\nBibliography.\u2014 Wharton, Adenographia. Morgagni, Adversaria Anatomica. Mailer, Elementa | Physiologica. Meckel and Cruveilhier\u2019s works on Descriptive Anatomy. Quain and Sharpey\u2019s Ana- ! tomy. Todd and Bowman, Physiological Anatomy. Simon\u2019s paper in Philos. Transact. 1844, on Comparative Anatomy of Thyroid. Various parts of the -essay of the same author on the Thymus gland, j Henle, Allgemeine Anatomie. \u0152sterlen, Beitr\u00e4ge zur Physiologie.\n( C. Handfield Jones. )\nTIBIO-FIBULAR ARTICULATIONS.\n\u2014 The bones of the leg, throughout the greater part of their length parallel and contiguous to each other only, are in contact by ( their extremities. At the points of contact the two tibio-fibular articulations, a superior and an inferior, are situated.\nSuperior Tibio-Fibular Articulation.\n\u2014The head of the fibula is in contact with the external tuberosity of the tibia. The former is furnished with an articulating surface which has an aspect upwards, forwards, and inwards, whilst the articular facet on the latter is placed rather towards the posterior part of the tuberosity of the tibia, and is directed downwards, backwards, and outwards. Both surfaces are almost perfectly plane, their form is circular, and they are encrusted with articular cartilage ; hence this articulation is to be ; referred to the class arthrodia.\na.\tThe ligaments of this joint are two in number, named, from their relative positions, anterior and posterior ligaments.\n1.\tThe anterior ligament of the superior tibio-fibular articulation, is composed of a fas- 1 ciculus of white fibrous bands, which are all parallel to each other, it passes from the tibia downwards and outwards to the head of the fibula, running in front of the synovial membrane of the articulation which it defends. The extensor digitorum communis muscle covers this ligament anteriorly.\n2.\tThe posterior ligament follows a similar direction on the posterior aspect of the joint ; but the fibres which compose it are neither so numerous nor so strong as those of the preceding; this ligament is covered posteriorly by the poplit\u00e6us muscle.\nLastly, the tendon of the biceps (flexor cruris), by its attachment to the head of the fibula, contributes, in no inconsiderable degree, to the security of the articulation.\nb.\tSynovial membrane.\u2014There is nothing, in the anatomical disposition of the synovial membrane of this articulation, which requires any particular notice ; but the surgeon should remember that it is always in close proximity to the serous sac of the knee joint, and that in many instances the two synovial membranes communicate with each other. The synovial","page":1118},{"file":"p1119.txt","language":"en","ocr_en":"TIBIO-FIBULAR ARTICULATIONS.\t1119\nmembrane of the knee joint is brought into this close relationship with that of the tibiofibular articulation, by means of a prolongation which passes downwards from the former around the tendon of the poplitaeus muscle ; and when a communication does exist between the two articulations, it will therefore be found at the posterior aspect of the head of the fibula.\nThis anatomical arrangement has an important bearing on a disputed point of practice, viz. the extirpation of the head of the fibula in amputations of the leg near the knee joint. This proceeding, recommended originally by Larrey and Garriques, and subsequently revived by Mr. Guthrie, has been opposed by Mr. Adams of Dublin, who, appealing to the anatomical peculiarities just described, makes them the grounds for rejecting altogether the innovation in question. (Vide \u201cAbnormal Condition of the Knee Joint,\u201d vol. iii. p. 50.)\nInferior Tibio-Fibular Articulation. \u2014This articulation is intimately connected with that of the ankle, from which, although anatomically distinct, it cannot virtually be separated.\nThe tibia and the fibula, at the lower part of the leg, are closely connected for a considerable portion of their extent. The tibia presents, on its external aspect and inferiorly, a triangular-shaped surface, two inches in vertical height, and concave from side to side : superiorly, or towards the apex of this space, it presents a rough and scabrous surface ; but inferiorly it is smooth and encrusted, in the recent state, with articular cartilage. The inner surface of the lower end of the fibula is of similar shape, but convex ; it is rough superiorly, and smooth inferiorly. Here the two bones form an arthrodial articulation.\na. The cartilage, which in this situation invests the opposed surfaces of the tibia and fibula, is continuous with that which covers the inferior surface of the tibia. It is also lined by\u2014b.\u2014synovial membrane prolonged upwards from the ankle joint, and which forms a small cul-de-sac in the tibio-fibular articulation. The rough irregular surfaces, on the bones above the line of reflexion of the synovial membrane, have the fibres of a strong interosseous ligament implanted into them.\nc. The ligaments of the inferior tibio-fibular articulation are three in number ; 1. are anterior, 2. a posterior, and 3. an interosseous.\nL Anterior tibio-fibular ligament.\u2014The fibres of this ligament pursue a direction downwards and outwards, from the anterior margin of the small articulating surface on the tibia to the outer malleolus ; and as the lower margin of this ligament projects below the level of the tibia, it deepens somewhat the cavity for the reception of the astragalus. The tendon of the peron\u00e6us tertius muscle covers this ligament in front.\n2. Posterior tibiofibular ligament.\u2014This is a strong, round, fibro-cartilaginous cord, which passes from one malleolus to the other in an arched manner, having a concavity directed\ndownwards, and connected with the posterior ligament of the ankle joint, and a convexity which adheres uniformly to the posterior articular margins of the tibia and fibula. This ligament not only connects the two bones to each other, but it also, like circumferential fibro-cartilages elsewhere, serves the purpose of deepening the mortice-shaped cavity of the ankle joint which it borders. It likewise prevents the immediate contact of the osseous surfaces in forced extension of the foot, being interposed between the bones as an elastic cushion.\n3. Interosseous tibiofibular ligament.\u2014This is composed of short transverse bands firmly implanted, at right angles, into the opposed rough surfaces on the bones already described. Superiorly, the fibres of this ligament extend nearly as far as the lower margin of the interosseous membrane, (separated from it by a small interval, through which passes a branch of the fibular artery), whilst inferiorly they are limited by the direct contact of the two bones of the leg, which they serve to bind firmly together. In order to exhibit this structure, either of two methods may be adopted ; the bones of the leg may be sawn across about their centres, and then forcibly torn asunder, (in this way the ligament maybe seen, and its powers of resistance appreciated), or the ligament may be exhibited in situ, by making a vertical, transverse, section of both bones, traversing the two malleoli, and also the joint of the ankle.*\nMechanism of the tibiofibular articulations. \u2014The movements of the fibula on the tibia are extremely limited ; this is in accordance with the general plan on which the skeleton of the lower extremity is formed, its use being to serve as an organ of support, and of locomotion, only. The bones of the leg are connected together by the intervention of ligaments, (not consolidated together as in the arrangement met with in a few of the Mammalia), and thus a greater degree of elasticity is obtained without any sacrifice of strength ; and it may be presumed that the slight degree of yielding and of gliding motion, which is permitted in the tibiofibular articulations, may occasionally serve to diffuse, and to lessen the intensity of shocks applied to the lower extremity, and may thus diminish its liability to injury, especially to fracture.\nDislocation of the fibula, at the upper tibiofibular articulation, has occasionally, but rarely, been met with as the result of injury. Sir A. Cooper mentions a case of compound fracture of the tibia, where this complication was observed ; but the rarity of dislocations in this situation, is accounted for by the circumstance, that the fibula, owing to its comparative slightness, almost invariably breaks, on the application of a force far short of what suffices to rupture its ligamentous connections with the tibia.\nThe mechanism of the inferior tibiofibular articulation is inseparably connected with\n* See fig. 61. p. 163. vol. i.","page":1119},{"file":"p1120.txt","language":"en","ocr_en":"1120\tTONGUE.\nthat of the neighbouring articulation of the ankle. In fact, on the perfect adaptation of the bones of the leg, at their lower extremities, essentially depends the integrity of the ankle joint itself.\nBy the union of the tibia with the fibula the \u201cmortice shaped\u201d cavity, which receives the pulley of the astragalus, is formed, and any injuries which disturb the natural relations of these two bones interfere proportionally with the functions of the ankle, which is a perfect angular ginglymus.\nHence it is, that in some cases of fracture of the lower end of the fibula, a widening of the mortice is produced, from which more or less of permanent deformity and inconvenience results, abnormal lateral motion being then permitted. The connecting media between the tibia and the fibula inferiorly are of extreme strength ; so much so, that no ordinary violence seems capable of rupturing them ; the bones being bound together, not only by the special ligaments of the inferior tibio-fibular articulation already described, but by the annular ligaments and fasciae of the leg also. Hence, as we might infer, the separation of these bones by injury has never been observed, except when the fibula has first been broken. In the \u201ccomplete dislocation of the'foot upwards and outwards, we are furnished with an illustration of the immense strength of the interosseous ligament ; as it is found that even in this severe injury the fibres of this ligament are not usually torn ; but the rough surface of the tibia into which they are implanted is broken off, and carried upwards and outwards with the lower end of the fibula, to which the interosseous ligament still binds it.\u201d (See b. fig. 54. vol. i. page 157 ; article \u201c Abnormal Conditions of the Ankle Joint.\u201d)\n(Ben. George JVDDoivel.)\nTONGUE. (rXwo-ffcr, Gr. ; Lingua, Lat. ; la Langue, Fr. ; Zunge, Germ. ; Lingua, Jtal.) The tongue is a symmetrical muscular organ, situated in the middle line, at the orifice of the gastric portion of the gastro-pulmonary mucous membrane, invested with the mucous surface, and subserving to the early stages of the process of digestion.\nHuman Anatomy. \u2014 The human tongue (in common with that of all mammalia) consists of, first, an osseous basis, itself movable, to which it is attached, and with which and on which it moves ; secondly, a muscular system, in part extrinsic, serving to attach it to certain fixed points and to move it on them, and in part intrinsic, constituting the bulk of its substance and moving it on itself; thirdly, a mucous investment, variously modified in different parts ; fourthly, a proper system of mucous glands ; fifthly, a small quantity of fibrous and areolar tissue ; sixthly, a still smaller quantity of fat ; seventhly, a large vascular supply ; and eighthly, an abundant distribution of nerves from three separate sources.\nSize. \u2014 The size of the tongue is very various. I have examined some tongues of\nadults that certainly were not more than half the size of others, and there does not seem to be any relation between the size of the tongue and that of the individual; but between it and the size of the alveolar arch there is a close relation, and hence we see it generally much smaller in women than in men. It has been generally stated that certain obscurities in speech are caused by too large a tongue, but there do not seem to be any well authenticated cases to prove that this supposition is correct. It may in some degree be explained by the fact, that paralysis, which would cause a thickness of speech, would also cause a flaccid half-protruded condition, and, therefore, an apparent increase of size, of the tongue.\nDirection. \u2014 In its anterior half it follows pretty much the direction of the lower jaw, that is, it tends forwards and a little downwards, but behind this it curves downwards and backwards, and ere it reaches the os hyoides has become quite vertical, so that the average of its direction would be downwards and backwards, and its posterior extremity much lower than its anterior.\nShape. \u2014 The tongue is of an ovoidal shape, the broad part being behind ; and the character of the curvature in front is parabolic, coinciding with the parabolic curve of the lower jaw : it possesses an exact lateral symmetry, and is flattened from above downwards, being thickest towards its base, and thinnest in front. When taken out of the body it seems to be flat, and in the same plane longitudinally, but when in situ it possesses a double curvature; one longitudinal, the most considerable, by which the upper surface is rendered convex, and by which the posterior part of the tongue is bent from a horizontal to a vertical direction ; the other, less considerable, affects the tongue transversely, and renders its posterior part concave in that direction : it is much increased by the contraction of the genioglossi, which draw the centre of the tongue down, or by that of the styloglossi, which draw its sides up. The longitudinal curvature, too, is very much affected by the position of the tongue, for when it is thrust forward, and the hyoid bone raised, the whole organ is much more horizontal, and the curvature almost effaced.\nGeneral description. \u2014 In consequence of its possessing a long axis, and being vertically flattened, the tongue presents for description a superior and inferior surface, two lateral borders, and an anterior and posterior extremity.\nThe superior surface, borders, anterior extremity, and anterior third of the inferior surface are free ; the posterior extremity and posterior two thirds of the inferior surface are attached. Along the line where the free and attached surfaces meet, we see the investing membrane leaving the tongue, and passing off to neighbouring structures, investing the loose areolar tissue by which in these situations it is underlaid, and forming a system of yielding and movable attachments. Thus at the base the mucous membrane passes off to the an-","page":1120},{"file":"p1121.txt","language":"en","ocr_en":"TONGUE.\t1121\nterior surface of the epiglottis, the sides of the pharynx, and upwards to the soft palate and posterior parts of the cheeks. As we proceed forwards we find it investing the sides, and gradually more and more of the under surface, reflected thence over the hyoglossi and ge-nioglossi muscles, the sublingual glands, vessels, and nerves, and much areolar tissue, which separate it from the mylohyoid muscle, to the inner surface of the alveoli of the lower jaw, wrhere it becomes continuous with the mucous membrane covering the gums.\nAt certain points where this membrane leaves the tongue it forms distinct folds, which, from their being constant, have received particular names, and which act to a certain extent as ligaments or frena of the tongue, not so much by virtue of their being folds of mucous membrane, as from their containing within their reduplications a certain amount of a more or less unyielding tissue ; in some this tissue is a mixture of white and yellow fibre, in others it is muscle.\nOf the first sort are three folds, a middle and two lateral, passing from the base of the tongue to the epiglottis, called the glosso-epiglottid folds, of which the central, which is always present, and has been called the posterior fr\u00e6num of the tongue, and fr\u00e6num epi-glottidis, is much the most considerable (fig. 745. d.') : they serve rather to check the movements of the epiglottis than as lingual ligaments. From the sides of the base of the tongue, passing thence to the soft palate, are seen four more folds, two on each side, which, from their position, have been called the pillars of the fauces. They are formed by the raising of the mucous membrane from the general surface by two muscles: the posterior, the least considerable, by the palato-pharyn-geus ; the anterior, more marked, by the palatoglossus. The interval between these two is called the amygdaloid fossa, from its being occupied by the amygdalae, or tonsils : the anterior pair taken together constitute the constrictor of the fauces, and the narrowing caused by the whole apparatus has received the name of the isthvius faucium. From the basis of these folds being muscular their prominence is liable to constant variety. But the most considerable of these folds, which is called, par excellence, the fr\u00e6num of the tongue (fr\u00e6num, frenulum lingu\u00e6), is placed beneath the anterior free extremity, which it connects with the lower jaw. It consists of a prolongation fox-wards, beyond the free border of the genioglossi, of the median fibrous lamina, which raises into a prominent fold the mucous membrane passing from the under surface of the anterior part of the tongue to the neighbouring alveoli of the lower jaw : it forms a strong ligament, and limits the backwai-d movement of the anterior extremity of the tongue. Sometimes an extreme shortness of this ligament is a congenital malformation, pi-eventing the free movement of the organ, and so impairing speech, mastication, &c., as to necessitate the operation known as cutting the tongue.\nVOL. IV.\nBefore entering into the specialities of the anatomy of the tongue, let us examine its\nFig. 745.\nI\nHuman tongue viewed on the upper surface or dorsum. (After Soemmering.')\ngeneral configui\u2019ation and external characters, taking its surfaces, exti*emities, See., in the order above enunciated.\nSuperior surface.\u2014 On regarding the upper surface of the tongue, we see first that it is divided into two symmeti'ical portions by a median longitudinal furrow (fig. 745. c.), commencing at the tip, and extending back about two thirds the length of the organ. It is superficial when present, but in many cases does not exist : it is the representative, in this part, of that median line which symmetrically divides all those organs of animal life that are situated in the middle vertical plane. It is very generally, but very incorrectly, stated* that this furrow terminates posteriorly in the foramen c\u00e6cum. The two have no relation ; the one often exists without the other ; and in every case that I have seen, the foramen has been separated from the posterior termination of the furrow by the ridge of the circumvallate papillae, sometimes by a long interval. This median furrow seems partly formed by the action of muscles, and partly by a deficiency of papillae. Another conspicuous character of the upper surface is, that the roughnesses with which it is covered are arranged in lines (fig. 745.), with a direction obliquely forwards and outwards, so\n* Bichat, Trait\u00e9 d\u2019Anatomie, t. ii. p. 594.\n4 c","page":1121},{"file":"p1122.txt","language":"en","ocr_en":"1122\nTONGUE.\nthat there is formed in the median line a series of angles pointing backwards. This disposition is seen to affect, more or less, all the structures with which the surface is covered. Thirdly, the upper surface of the tongue is seen to be divisible into a smooth and a rough portion. The smooth, or non-papillary portion, occupying nearly the posterior third,is characterised by smooth nodular rugosities (fig- 745. e), formed by small muciparous glands, which are abundantly distributed beneath the surface, and occupy the whole space between the papillae and epiglottis : they are smallest and most scattered behind, where they are gradually lost ; larger and more prominent in front, where, from their being disposed in the direction already indicated, they form a prominent V-shaped ridge with the opening directed forwards. Just in front of this, separated by a groove, is another V-shaped ridge, more definite, but less constant in shape, formed by two converging lines of button-like eminences, each surrounded by a circular raised border of more or less regularity ; these compound organs are the circumvallate papill\u00e6 {fig. 745. ff ). At the angle formed by the convergence of their two rows, generally a little behind that angle, is situated a cul-de-sac of very variable size, which has received the name of foramen c\u00e6cum (Je trou borgne, lacune de la langue), and which was formerly regarded as the orifice at which several convergent salivary ducts terminated* ; these supposed salivary ducts were afterwards shown by Duver-noy-j' and Haller! to be merely small veins. Meckel considered that this foramen c\u00e6cum was nothing but a largely developed calyx of a caliciform papilla, of which the central portion was small, or wanting, or misplaced ; that if the central eminence was well developed and in its proper situation, the foramen c\u00e6cum was wanting, and that it only existed from some of the irregularities above mentioned; an opinion adopted by Cruveilhier, and by Professors Todd and Bowman in this country. Meckel states that he has seen two, one a great way behind the other. I have more than once met with the -same appearance. In these cases the anterior one has always contained ,a well developed papilla. It can evidently perform no essential office, as it is so often wanting. The whole of the superior surface of the tongue, in front of the circumvallate papill\u00e6, comprising its anterior two thirds, is covered by an investment of coriaceous or filamentous asperities, longest in the central parts, and arranged with the most regularity at the back, where they are distributed in lines of more or less distinctness, with a direction obliquely forwards and outwards (fig. 745. i if. These eminences are seen to be of two sorts ; one of a spheroidal shape, distinguished during fife by their red\n* Coschwitz, De Ductu salivali novo. Halle, 1724.\nf Loc. cit.\ni Exp. et Dub. circa Ductum Coschw. Leyden, 1727.\ncolour, and scattered here and there at the posterior part, edges and tip, \u2014 these are the fungiform papill\u00e6 (fig. 745. h.) ; the others, occupying the whole of the rest of the surface, are the conical and filiform. To the minute consideration of these structures a future part of this article will be devoted.\nInferior surface. \u2014 This surface is attached in its posterior two thirds by the muscles passing from it to the hyoid boue and lower jaw. The most posterior part of this attachment is as wide as the tongue itself, so that there no portion of the inferior surface is free ; but in front of this the attachment narrows, so that the lateral portions become increasingly free till they meet at the fr\u00e6num, in front of which they involve the whole surface. The longitudinal furrow is much more distinctly marked here than above, and is constant ; it passes from the tip, on which it is continued, to the fr\u00e6num. On each side of the furrow the ranine veins are seen passing forwards, and immediately beneath the tip is a little cluster of mucous glands first described by Nuck*, and also by Nuhn.-f The mucous membrane here is quite smooth and free from any visible papill\u00e6.\nThe edges of the tongue, which separate its upper and under surface, are thick behind and gradually become thinner in front ; they are marked by a series of vertical ridges, separated by corresponding furrows, very distinct on the upper, and gradually becoming lost as they approach the under, surface. They are very conspicuous at the posterior part, but disappear anteriorly, and they differ very much in their development in different subjects. They are, essentially, fused conical papill\u00e6. At the upper and posterior part of the edges are also a series of small mucous glands.\nThe anterior extremity, apex, or point (fig. 745. b.), is flattened or rounded, blunt or pointed, according to the movements of the tongue, and slightly impressed by the median furrow which is continued on it: it is not marked by any of those vertical ridges that characterise the edges.\nThe posterior extremity, or base.\u2014 Ere the tongue reaches the os hyoides it becomes very flat and thin, and this from two causes \u2014 diminution in the quantity of the intrinsic muscles, and the passing off of the extrinsic in other directions ; so that instead of being very thick, as is generally described, the base is in reality the thinnest part of the whole organ. It is flattened antero-posteriorly and much extended laterally, and by its attachment to the hyoid bone is curved in a horseshoe shape, which, however, is much effaced by the insertion of the epiglottis in the area of the curvature. It is constituted laterally by the hyoglossi, centrally by the hyoglossal ligament, anteriorly by some fibres of the genio-glossus, and behind and above by the mucous membrane passing from it over the\n* Sialographia, Ductuum aquosorum anatome nova. Leyden, 1690.\nf See Art. Salivary Glands, p. 426.","page":1122},{"file":"p1123.txt","language":"en","ocr_en":"TONGUE.\nepiglottis. It contains less muscular and more fibrous tissue than any other part of the tongue.\nSuch, then, is a general description of the tongue, \u2014 such are the appearances that present themselves to the eye, on regarding its external surface and configuration. Let us now examine these structures more minutely, and, to facilitate that examination, arrange the parts that contribute to the formation of the organ, according to the office they fulfil, or their absolute nature.\nRegarding the tongue in this light, we find that it may be considered as consisting of three systems,\u2014\n1.\tA basis, or system of support.\n2.\tA muscular system,, or system of movement.\n3.\tA tegumentary investment, or system of sensation and protection.\n1. Basis, or framework of the tongue.\u2014This consists of the hyoid bone, the hyoglossal membrane or ligament, the median fibrous septum (the cartilaginous lamina of M. Blandin), and, fourthly, to these may perhaps be added, on account of its density, and its giving attachment to most of the intrinsic muscles, the compact fibrous tissue, or cutis, beneath the mucous membrane.\nFig. 746.\nHyoid lone. A. seen from above, and B. in profile. (Natural size).\na. The hyoid bone (os hyoides, \u2014upsilo'ides, \u2014lingualis,\u2014 lingu\u00e6), called also the lingual or tongue bone, has received its name from its resemblance to the Greek*v ; it is the homologue in man of a very complex mechanism in the lower vertebrata, from which circumstance it is sometimes called the hyoid apparatus. It consists of a bony arch, with a curvature nearly approaching a parabola, the convexity being in front ; \u2014 situated in an almost horizontal position behind and rather below the lower jaw. In the lower vertebrata the hyoid bone is connected to the rest of the skeleton by bony media ; in man, by the substitution of a ligament (the stylohyoid) for a part of this osseous connection ; it is isolated, and disconnected from all\n1123\nthe other bones.* It performs the triple office of a basis of the tongue, a point of support to the larynx, and a point d\u2019appui or fulcrum, by which the contractions of the intrinsic muscles of the tongue and larynx may be impressed on those organs : it may also be looked upon as the first part of that framework (afterwards generally continued by cartilage) which secures the permanent patulence of the respiratory passages. It is retained in its place by muscles and ligaments, which, converging to it from different directions, effectually prevent its displacement : thus it is tied upwards and backwards by the ligament and muscles from the styloid process, in front by the muscles from the chin and lower jaw, below by those from the thyroid cartilage, sternum, and scapula. Placed between the tongue and larynx, it impresses on each the movement of the other, and is the medium by which the motions of these two organs are so intimately associated.\nRelations. \u2014 Its whole external surface is devoted to muscular insertions, which separate it, anteriorly and laterally, from the cutaneous structures. Behind, it is in relation with the epiglottis, from which it is separated by some dense cellular tissue, and by the thyrohyoid membrane, and with the mucous membrane of the pharynx.\nIn man the hyoid bone consists of five pieces, \u2014 the basis or body, two greater cornua which project backwards from the sides of the body in a direction nearly horizontal but a little upwards, and two lesser cornua, surmounting the body and greater cornua at the point of their union.\nThe body is' quadrilateral, compressed an-tero-posteriorly, curved, and laterally extended. Its anterior surface looks upwards, is convex, and intersected by two irregular ridges, a vertical and horizontal, which at the point of their union project in a prominent tubercle, which is the analogue in man of an additional element of the hyoid apparatus in the lower animals \u2014 the true lingual bone (glossohyal) : this tubercle is sometimes bifurcated. The portion above the transverse ridge is directed much more upwards than that below, so that it has sometimes been called the upper surface : in that case the portion below is described as the whole anterior surface, a circumstance which has led to much confusion with regard to the nomenclature of muscular insertions into this bone. The posterior surface is concave, and looks downwards ; it is marked by many little foramina entering the cancellous structure, and is sometimes covered by a synovial membrane. The lateral surfaces, small and articular, are connected to the anterior extremities of the greater cornua by a lamina of temporary cartilage, which,however, is seldom completely ossified, and which admits a certain amount of movement between the different\n* In some rare cases this ligament has been ossified, and then the condition of the os hyoides is the same as that found in most quadrupeds, fish, and reptiles.\n4 C 2","page":1123},{"file":"p1124.txt","language":"en","ocr_en":"TONGUE.\n1124\nparts. The superior border presents a double curvature, something like the upper lip of the mouth, i. e., it curves downwards at its extremities, and has a little dip in the middle. The inferior border, of less extent, is thinner, horizontal, and placed on a plane anterior to the upper.\nThe greater cornua are at least half as long again as the body, from the sides of which they project, at first a little outwards and then backwards ; they possess a shaft and two extremities. The anterior extremity is large, club-shaped, tuberculated, and curved inwards towards the body, for its attachment with which it presents an articular facet ; the shaft tapers gradually posteriorly, and is laterally flattened, so that it has an outer and inner surface, and an upper and lower border. Its outer surface, which is continuous with the anterior surface of the body, looks a little upwards ; its lower border is smooth and rounded ; its upper border sharp, and, from the obliquity of the surfaces, of less extent than the lower. The posterior extremity is expanded into a little tubercle, sometimes surmounted by an epiphysis.\nThe lesser cornua (ossa pisiformia lingualia, of Soemmering) are two little pyramidal or pisiform nodules, projecting upwards, outwards, and backwards, from the point of union of the greater cornua and body : they are seldom completely ossified. They are the homologues in man of a very considerable process (the ceratohyal) in the lower animals, in some of whom the proportion between the lesser and greater cornua is inverted.\nStructure \u2014 Chiefly compact, buc a little cancellous in the body and large extremity of the greater cornua.\nDevelopment. \u2014 From five points ; one for each element. Vesalius saw a case in which there were six, there being two for the body. The ossification commences in the greater cornua ; it then takes place in the body, where it begins soon after birth ; and, finally, in the lesser cornua, where it does not commence till some months after. It proceeds but slowly, and generally leaves a thin lamina of cartilage unossified, so that complete anchylosis of the different parts into one bone is comparatively rare.\nThe morphological value of this bone and its homological relations, will be treated of hereafter.\nb.\tThe hyoglossal membrane or ligament. \u2014 This is a vertical transverse lamina of very dense areolar tissue, containing a large proportion of the yellow element, passing upwards from the upper border of the body of the os hyoides to the tongue, between which it constitutes a means of union. The muscular connection of the tongue with the hyoid bone by means of the hyoglossus is deficient in the central part of the body of that bone, and, consequently, this ligament is, in that situation, the only direct bond of connection. It is dense, yellow, and very elastic, and has a little fat dispersed among it, though this is denied by Bichat. It may be\ntraced upwards into the tongue, sometimes as far as an inch. It receives on its anterior face those fibres of the genioglossus that lie immediately above those that are inserted into the hyoid bone, and also some of the intrinsic longitudinal fibres of the tongue that terminate upon it ; posteriorly it is in relation with the upper part of the epiglottis and the mucous membrane reflected upon it from the tongue ; in fact, it immediately underlays the glosso-epiglottid folds. Above, it is gradually lost in the muscles of the tongue ; below, it in part terminates in the upper lip of the body of the os hyoides, and in part is continued on behind this bone, constituting the yellow elastic tissue already referred to as being interposed between it and the epiglottis. This ligament has been well described by Bichat.*\nc.\tMedian fibrous septum (median cartilaginous lamina, Blandin). \u2014 Springing from the anterior surface of the last-mentioned structure, interposed between the two ge-nioglossi muscles, passing forwards between these two muscles as far as their genial origin, upwards to the dorsum of the tongue as far forwards as its centre, and thence to the anterior free border of the genioglossi, and a little beyond that border, is a vertical lamina of fibrous tissue. It is thick and dense behind and below, but gradually becomes thinned out as it spreads upwards and forwards; as it gets thinner it becomes cribriform, like the septum of the corpora cavernosa penis, the areolae giving transmission to the transverse muscles of the tongue, which pass through it from side to side. It varies much in different individuals ; in some it is tolerably dense, in some it is merely a fine areolar web. This structure M. Blandin has dignified with the name of\u201c median cartilaginous lamina,\u201d and has described it as consisting of a vertical sheet of that substance of more or less extent. I have, however, looked in vain for any thing like cartilage or fibro-cartilage in any part of it. It appears to me to be nothing more than intermuscular areolar tissue in rather greater amount and density than usual, which happens to be placed in the median plane. It has been supposed by some to be the analogue of the small fusiform slip of cartilage placed beneath the extremity of the tongue in the dog and wolf, with which, however, it has no relation : that structure is essentially distinct. Others have found in it the analogue of the lingual bone, a conception still more far-fetched. It has been supposed to give origin to muscular fibres by its two surfaces. This I have failed in detecting ; certainly it does not give attachment to any of the transverse fibres of the tongue, to which it might be supposed it would, if to any; for they may be seen, by transverse sections viewed with the microscope, to pass, without exception, from side to side of the tongue, without any break in their median plane.\nd.\tLastly, the investments of the tongue, including the papillary structures and the true\n* Trait\u00e9 d\u2019Anatomie, t. ii. p. 596.","page":1124},{"file":"p1125.txt","language":"en","ocr_en":"TONGUE.\t1125\ncutis underlaying them, may be looked upon, in one light, as apart of the framework of the organ. They form a dense and unyielding envelope, tending to preserve its shape and give it firmness and support, and at the same time affording attachment to a great number of its muscular fibres.\nSuch, then, is a concise description of the framework of the tongue. The first and last-mentioned elements of it are, doubtless, the most important; but it will be seen, at a future page, that the intrinsic arrangement of the tongue\u2019s muscular fibres is such that they mutually support each other, and tend to keep the organ firm and compact, which obviates the necessity of any considerable structures especially destined for that purpose.\n2. The muscular system. \u2014 Constituting the chief bulk of the tongue, imparting the required consistence to it, performing the majority of its functions \u2014 prehension, mastication, deglutition, speech,\u2014 and necessary even to the perfection of taste, the muscular system of the tongue may be considered the most important of all.\nThe muscles of the tongue are of three sorts, and admit of the following arrangement :\na. Intrinsic.\nh. Extrinsic.\nc. Accessory.\nThe intrinsic muscles are those which form the substance of the organ, that pass from part to part of it, and that move the tongue on itself.\nThe extrinsic (proper') are those that, as well as entering in some degree into the substance of the tongue, pass from it to neighbouring fixed points, to which they attach it, and on which they move it.\nThe accessory are those which, though not contributing in any degree to the formation of the tongue, nor attached to it, are yet engaged in all its extrinsic movements, acting as coadjutors to those proper extrinsic muscles whose direction coincides with theirs.\nOf the two first I shall speak particularly : little more than their enumeration will suffice for the last.\na. Intrinsic muscles of the tongue. \u2014 There are three methods of investigating the arrangement of the tongue\u2019s intrinsic muscular structure : first, by the ordinary method of dissection, or separation ; secondly, by making sections in different planes, and examining the appearance of the cut surfaces ; thirdly, bv the microscopic examination of thin sections. The first, which is the oldest, is that by which we gain the least information ; and to its adoption must be attributed the fact that so many of the older anatomists were in the dark on this subject. By it we merely learn the following facts : that certain of the extrinsic muscles pass into the substance of the tongue and contribute to certain of the intrinsic ; that the direction of most of the superficial fibres is more or less longitudinal ; that the direction of the more deep-\nseated fibres is not longitudinal; that it is complex, and incapable of demonstration by separation.\nThe second method furnishes much more certain information. By making the sections in different planes, we vary the point from which we regard them ; and the section made in one plane corrects, and supplies the deficiencies of, the other. The transverse vertical section is the most important; and to this I shall chiefly refer.\nOn making a transverse vertical section of a human tongue, at a point just behind the anterior free margin of the genioglossus (fig. 747.), the following are the appearances. Immediately within the cutis, which is seen to be tolerably thick, especially at the centre of the dorsum (fig. 747. a.), is seen a dark red stratum,\nFig. 747.\na\nTransverse vertical section of human tongue just behind the free portion.\na, upper surface, showing the thickness of the cutis there ; b, cortical portion ; c, central portion, where the vertical fibres are seen crossing the transverse ; d, genioglossi muscles ; e e, sublingual glands.\nalso thick in the last-mentioned situation, thinner at the lateral regions, and again thicker as it curves inwards on each side of the inferior surface. This is very dense, and cuts with a perfectly even surface. I shall call it the cortical portion (fig. 747. b.). Within this and surrounded by it as by a border, is an area of a more or less oval form, of a paler colour, less dense, and showing a distinctly fibrous character. The fibres appear for the most part transverse (fig. 747. c.), horizontal in the centre, but curved up a little on each side. They are bounded on all sides by the cortical portion. Entering the centre of the bottom of the section, passing vertically upwards, crossing the last-mentioned fibres at right angles, and terminating in the superior surface of the cortical portion, are seen the two genioglossi muscles (fig. 747. d.). These, therefore, constitute a vertical set of fibres ; but they are not the only vertical fibres ; at each side of them, especially at the inferior portion of the section, other vertical fibres are seen passing upwards and a little inwards, and intersecting the more lateral portions of\n4 c 3","page":1125},{"file":"p1126.txt","language":"en","ocr_en":"1126\tTONGUE.\nthe transverse at right angles.* Cruveilhier has erroneously described them as passing downwards and inwards: their divergence as they pass downwards is very conspicuous. The central area\u2014 the Ungual nucleus {noyau lingual) of Bauer, \u2014 is therefore constituted of two sets of fibres, a ventrical and transverse ; the transverse being entirely intrinsic, and the vertical in part intrinsic and in part derived from the genioglossus.\nA section made anterior to the free margin of this last-mentioned muscle, shows the cortical portion continued completely round the tongue, without the break on its inferior surface, occasioned, in the previous section, by the entrance of the genioglossi muscles; it is also of greater thickness in proportion to the central part, which is comparatively small, and the transverse fibres have a less marked upward curvature at their extremities.\nThirdly, a section made near the base of the tongue shows the cortical portion nearly lost at the upper surface, greatly accumulated at the sides, but not of so compact anature as in more anterior situations; the obliquely vertical fibres tolerably abundant, but the transverse nearly lost, and the greater part of the inferior surface occupied by the expanded genioglossi.\nTransverse vertical sections, therefore, display two sets of fibres, a vertical and a transverse, and shew their situation and quantity ; let us now see what additional light will be furnished by a longitudinal vertical section. It shews that the cortical portion consists of longitudinal fibres., and thus supplies a third set. If the section be made in the middle line, or near it, the v/hole cut surface is occupied by the .vertical fibres .of the geniohyoglossus, at first directed backwards, but curving upwards so as to enter the tongue vertically, in which vertical direction they are continued up through its entire thickness, and are lost in the longitudinal fibres of the cortical portion ; if the section is made in the lateral portions, it shows the vertical striation occasioned by the intrinsic vertical fibres, and the cortical portion, as in the other. Having ascertained the situation and direction of the three sorts of fibres, we may, by making transverse sections at all points from the apex to the base, and longitudinal ones at various distances from the vertical median plane, and also by tracing the extrinsic longitudinal muscles into the intrinsic, and seeing what part of the one the other furnishes, get an exact interpretation of them. We should then find the tongue to consist of the following muscles.\na. A transverse lingualf, altogether intrinsic,\n* Theile denies the existence of the intrinsic vertical fibres ; he says that those seen in longitudinal section are the ascending fibres of the genioglossus, and those seen besides them in transverse sections are the most oblique of the transverse ; \u2014 a misconception of which the microscopical examination of sections at once shows the fallacy.\nf The adoption of the word lingual for all the intrinsic ^muscles of the tongue, from the French writers on this subject, has no objection against it, and has the advantage of brevity.\ninserted on each side into the submucous fibrous tissue or cutis, continued from apex to base, more abundant anteriorly, where it is horizontal, becoming more curved upwards as we proceed backwards, and being lost at the base.\n1$. A vertical lingual, in part intrinsic ; in part the lingual portion of an extrinsic muscle, the genioglossus, existing from apex to base, in all parts vertical to the surface, and therefore, from the curved direction of the tongue, arranged in a more or less radiating or fanlike manner.\n7. A superior lingual, longitudinal, intrinsic, thin behind, thicker in the middle, and thinner again at the apex, arising from the hyoglossal membrane and cutis at the base jof the tongue in a gradual way, and having a similar cutaneous insertion on the upper surface of the tip and neighbouring parts.\n5. A lateral Ungual, longitudinal, altogether extrinsic in its origin ; derived from two principal sources ; one, its upper and most superficial portion from the fibres of the styloglossus, which pass forward on the side of the tongue after the insertion of that muscle into it, the other from the anterior fibres of the hyoglossus which have a similar distribution : to this may be added a slender fasciculus of fibres interposed between the styloglossus and hyoglossus, which many modern anatomists * have described as the lingual muscle. The muscle thus formed constitutes the accumulation of longitudiual fibres before referred to as seen at the sides of a transverse vertical section of the base ; passing forwards they become fused together and spread out so as to constitute a thin layer, merging above by converging towards the medial plane of the dorsum, in the superior lingual, below in that next to be described, and forming with them a sheath of longitudinal fibres, investing the whole surface of the tongue.\ne. An inferior lingual, a stout fasciculus of longitudinal muscular fibres entirely intrinsic, arising at the base of the tongue between the hyoglossus and genioglossus, and passing forwards between these two muscles to be inserted gradually into the cutis of the tongue on the inferior surface near the apex. This is the true lingual muscle of Douglas and Al-binus, and of anatomists of the present day. I am doubtful whether or not the most anterior fibres of the genioglossus bend forwards so much as to become longitudinal, but I think not (though Cruveilhier sajs they do): if they do, the longitudinal sheath in front of the free margin of the genioglossus would consist of four sets, behind it of three.\nSince the longitudinal fibres invest the whole of the free surface as a sheath ; since they are, most of them, not directly, but obliquely, longitudinal ; and since many of the central spread out to the sides, while the lateral converge to the centre, the division of the longitudinal linguals into superior, lateral,\n* Bichat, Trait\u00e9 d\u2019Anatomie, t. ii. p. 43.","page":1126},{"file":"p1127.txt","language":"en","ocr_en":"tongue.\nand inferior must be to some extent arbitrary : however, most of those on the upper surface are intrinsic in their origin, those at the sides are extrinsic in their origin, while those on the inferior surface are sufficiently individual and distinct: some subdivision appears necessary, and the one adopted will at any rate assist in remembering these facts.\nThe microscopical examination of thin sections. On making a thin transverse vertical section of the human tongue, and examining it with\n1127\nthe microscope#, we see that the appearances indicated by a similar section, viewed with the naked eye, are correct, namely, that the intrinsic muscular fibres assume three principal directions, a vertical, a transverse, and a longitudinal ; and that the longitudinal are confined to the neighbourhood of the surface. But we see more; we see a very curious and artificial arrangement of the fibres very much contributing to facilitate their package, and by which they mutually support one another\nFig. 748.\nTransverse vertical section of the left half of the hitman tongue at the most posterior part of the free\nportion. (.Magnified 10 diameters.)\na a cutis- h b cortical portion, consisting of the three orders of fibres; c central portion consisting only of \u2019 two discs of longitudfnal fibres, seen in sectinn; \u00a3hjn* **n\u00a3 mBehan gane; a line of emergence of the vertical from the transverse fibres; i, i', the most superior ana lmenor of th(ftransverse6curving up and down; k, k, the most lateral of the vertical curving outwards. .\n* The best method to adopt in making these\ninvestigations is to keep a fresh human tongue two or three days in spirit, and then boil it about an hour. On being first put into the boiling water it contracts and becomes very hard. When sufficiently boiled, let it dry in the air for a day, and then make\nthe sections with some very thin flat knife. Place the sections on a glass slide with a drop or two of water, cover them with a piece of thin glass, and view them with an inch, or, if a very large field is wanted, a two-inch object-glass.\n4 c 4","page":1127},{"file":"p1128.txt","language":"en","ocr_en":"1128\nTONGUE.\nand act with the greatest advantage. This arrangement I shall now proceed to describe.\nSuppose the section made at a point just in front of the anterior free border of the genioglossi {fig. 748.). Immediately beneath the papillae (which may be very well displayed by this method), the condensed submucous areolar tissue or cutis of the tongue is seen, of considerable thickness, being thickest on the upper surface, especially towards the middle (aa). Immediately beneath this, around the whole circumference of the tongue, is seen a very curious areolated or fenestrated appearance, consisting of cross bars, branching and interlacing irregularly at various angles, leaving interspaces that are filled up by groups of discs (dd). The cross bars are at once seen to be small fasciculi of the vertical or transverse fibres, or both, according to the part looked at, and the groups of discs are seen to be transverse sections of the longitudinal fibres passing through the meshes formed by the vertical and transverse, which they more or less completely fill, and with whose shape they more or less exactly correspond {figs. 748. and 751.). The fasciculi of the longitudinal fibres are in most situations much larger than those of the vertical and transverse, among which they are contained ; indeed, the longitudinal being confined to the surface, it would naturally be expected that they would preponderate there. The vertical fibres are most abundant in the vertical median plane and the horizontal in the horizontal median plane (/), the vertical not existing near the lateral surfaces, nor the transverse near the superior and inferior sui'face {figs. 749. a, a) ; and from this fact result almost all the peculiarities of arrangement of the fibres that we see.\nIn the first place it results from this, that the vertical and horizontal fibres cross each other in the centre, which they entirely occupy, and therefore exclude the longitudinal ; accordingly no discs are seen in the central part of the tongue. Secondly, that at a certain line {fig. 748. g.) the vertical emerge from the transverse, and are continued up or down, to the superior or inferior surface, alone; and similarly at the lateral regions the transverse emerge from the vertical, and are continued on alone to the cutis at the sides ; hence the fibres near the middle of the upper and under surface, and at the borders of the tongue, do not interlace but pass to the surface with something of parallelism; and hence the fasciculi of longitudinal fibres here are arranged, not as in the mesh of a network, but in parallel rows at right angles to the surface ; an arrangement very characteristic of these situations. Thirdly, it would result from this absence of vertical fibres at the sides, and of the transverse above and below, that there would be four situations {b, b, b, b, fig. 749. a .) in the neutral ground between the upper and under surfaces and the borders respectively, where there would be no cross fibres of any sort, and where the longitudinal fibres would exist alone, unsupported\nand unseparated. Moreover, the vertical fibres at the upper and under surface, and the trans-\nFig. 749.\nJii\t\t111\t\u00ca\tm\t\tWrA\n|g|jfhtfffF\t\t\t\t: \u25a0 - -\t\t\n\tSi\t111 a\tI\t1\til\tz - -}-m-\u2014;\nPlan of the intrinsic muscles of the tongue as seen in transverse section.\na, a, a, a, Superior, inferior, right and left lateral regions ; b, b, b, b, right and left supra and sub-lateral regions. (Compare wither. 4.).\nverse at the sides, would be so dense and numerous that they would hardly admit of any longitudinal fibres in their interspaces. Now the support and separation of the longitudinal fasciculi, and the admission of a sufficient number of them at all the superficial parts of the tongue (especially the two surfaces and the two edges, which may be called the cardinal points of the tongue with regard to its movements), are the two things that are especially to be brought about. To achieve this double object, the vertical and horizontal fibres, as they approach their respective surfaces, spread out in a sort of fan-like manner ; the most lateral of the vertical fibres spreading out towards the sides {fig. 748. k, k), and the most superior and inferior of the transverse spreading up and down towards the surfaces {fig.748. i, i,fig. 749. b.). The two sets thus cross each other and fill the otherwise empty space with a network of considerable regularity and beauty, which is characteristic of these four situations, as the parallel fasciculi at right angles to the surface are characteristic of the four intermediate ones. For the sake of convenience I shall call the situations where the transverse and vertical fibres approach the surface in parallel bundles, the superior, the inferior, and the right and left lateral regions {fig. 749. a,b. a, a, a, a) : those in which they decussate as they approach the surface, I shall call the right and left supra-lateral, and the right and left sub-lateral {fig. 749. B.b,b, b,b.). Fourthly, the mesial vertical and mesial horizontal plane are the situations where the vertical and horizontal fibres respectively would act with the greatest power on the form of the tongue, and where also they would admit of being the","page":1128},{"file":"p1129.txt","language":"en","ocr_en":"TONGUE.\t1129\nlongest ; hence we see the fasciculi in these situations much larger and more densely packed than in the intermediate positions, so that they more than equal the longitudinal fibres that they transmit. The extreme lateral fibres, on the other hand, that spread out and interlace, having little more for their office than to support the longitudinal fibres, are very small and scanty, many of them consisting of only a single fibre, and hence at these points the preponderance of the longitudinal over the vertical and horizontal fibres is the greatest. Fifthly, the most deep-seated of the longitudinal fibres of the upper and under surface are underlaid by a definite floor of transverse fibres, and similarly the deepest of those at the side are underlaid by a floor of vertical fibres; therefore in these situations there is a strong line of demarcation, the discs are abundant down to the bottom of the cortical layer, and there they terminate suddenly {fig. 751.); but in the intermediate positions there is no definite floor, no line of demarcation, but the discs of longitudinal fibres dip down at irregular distances {figs. 748, 749, 750.).\nThis is the general plan and rationale of the arrangement, but it is rather an exposition than a description, and it must be understood as merely referring to a transverse vertical section of the tongue, made at the most posterior part of the free portion of the tongue : there are often irregularities that make it difficult to recognise the plan, and, in some situations, certain disturbing forces, and su-peradded parts that quite upset its symmetry. For example, behind the anterior third of the tongue, the genioglossus is seen entering its inferior surface, and displacing all longitudinal fibres {fig. 747. d) ; further back, this displacement is more considerable, and we have similar infringements from other muscles ; and the intermixture of fat towards the base of the tongue tends materially to upset the regularity of the muscular arrangement. Yet, in spite of this, it may always be detected, and the average of appearances will be such as I have described.\nThe muscular fibres are neither straight nor parallel ; those of each system maintain their general direction, but their course is wavy and tortuous, and characterised by the utmost irregularity ; as the fibres pass outwards they branch and sometimes re-unite {figs. 750, 751.), though their branchings are much more frequent than their re-unions, and hence the fasciculi are smaller and more numerous near the periphery than towards the centre {fig. 751.) ; by these branchings of the fasciculi each set of fibres, the vertical or transverse, possesses what may be called an intrinsic network, imperfectly marked certainly, but sufficient in some parts to mask their parallelism and to break up the rows of longitudinal fibres that are packed between them.\nThe number of fibres in each of the vertical or transverse fasciculi, varies according to the part of the section viewed, and the situation\nin the tongue irom which it is taken ; sometimes one single fibre constitutes the fasciculus, if one may say so, sometimes many dozen. Some of the largest are the most superior of the horizontal,\u2014 those that curve up on each side towards the upper surface {fig. 750.). The same variety of size exists in\nFig. 750.\n\nPortion of cortical layer of the right supra-lateral region of the tongue, showing the interlacement of a, a, the horizontal with b, b, the vertical fibres, the longitudinal fibres filling the intervals having been removed. Magnified 30 diameters.\nthe discs of longitudinal fibres cut across; the number of fibres in them may be counted, from two or three to thirty or forty : those nearest the surface are certainly the smallest, and they do not completely fill the meshes of the muscular network through which they pass {fig. 751.), but a certain quantity of fibrous tissue dips down among them : this, however, only for a little way. The shape of the longitudinal bundles is as various as their size\u2014 circular, polygonal, triangular, elliptical, in fact, every conceivable shape {fig. 751.); they seem moulded by the fibres among which they lie, or, more correctly, they and the others among which they lie, mutually regulate each other\u2019s shape and direction.\nThe peculiarity, then, of the arrangement of the intrinsic muscles of the tongue is this : \u2014 that there are three sets of fibres passing through the same area, and acting in three different directions; that these three directions are, in the main, at right angles the one to the other, in fact, that they coincide with","page":1129},{"file":"p1130.txt","language":"en","ocr_en":"1130\tTONGUE.\nthe three axes of the cube ; that to facilitate this arrangement, a beautiful system of pack-\nFig. 751.\nCortical layer from upper surface. (.Magnified 30 diameters.)\na, vertical fibres; b, topmost stratum of the horizontal; c, longitudinal, in section, occupying the interspaces between the vertical.\nacre is adopted, whereby each of these is enabled to pass in a straight line to its destination without being interfered with by the other two ; whereby the individual bundles of each set are isolated from their fellows ; whereby the whole of them are contained in the smallest possible compass ; whereby they not only admit the passage of, but mutually support and conduct each other ; whereby, in consequence of this, they are enabled to dispense with the support of cellular tissue, which accordingly we find absent ; whereby, lastly, the tongue contains the greatest amount of muscular tissue possible for its bulk. This system of package consists of this \u2014 that the crossing of the fibres of any two sets forms a lattice work, or mesh, through which the third shall pass, and that the successive layers of the crossing fibres shall be so arranged that the areol\u00e6 shall form continuous channels for the transmission of the perforating ones. In whatever plane we look at the fibres, we find that this is the case \u2014 that two sets are crossing fibres and one set perforating that two are seen in profile, one in section ; but, as we vary the plane, so do we vary the appearance of the fibres, one set alone remaining the same and two interchanging. Thus, in a transverse vertical section the transverse\nand vertical fibres are seen in profile, and the longitudinal in section ; in a longitudinal vertical section the vertical and longitudinal are in profile, and the transverse in section ; while again, in the horizontal section, the transverse and longitudinal are seen in profile, and the vertical in section. So, no set can be called a perforating set or a crossing set,\u2014 they are all equally so.\nAgain, we see that the office of the longitudinal fibres requires that they should have that special superficial arrangement which is the only one left them by the necessary disposition of the other two. The chief office of the longitudinal fibres is to alter the direction of the tongue longitudinally, to twist it from side to side, or up and down ; any thing but a superficial distribution would render them powerless for this act. For if the longitudinal fibres were placed in the centre, it is evident that they could only shorten the tongue; but,being arranged superficially, when a portion of them contracts, that side of the tongue on which the contracting ones are is shortened more than the rest ; in other words, the tongue is turned towards that side ; and it is only when the whole sheath of longitudinal fibres acts equally that the tongue is contracted directly backwards.\nHaving premised this general description, I shall now proceed to give a particular account of the microscopical appearances of successive sections made in the three principal planes\u2014the transverse, the longitudinal, and the horizontal. I shall begin with the transverse as being the clearest and the most illustrative.\nThe first transverse vertical sections, made at the tip of the tongue, of course remove successive portions of the papillary structure : we next come to the cutis\u2014the dense areolar tissue subtending the papillae \u2014 and many sections are made before the appearance of any muscle ; we have in fact to get through the thickness of the cutis. The first muscular fibres that make their appearance are the transverse, consisting of a single slender bundle of fibres in that direction, occupying nearly a middle plane between the upper and under surfaces, lying horizontally, collected into a single bundle in the centre, but breaking up at each end into smaller fasciculi, which diverge as they pass to their insertion into the cutis at the sides of the tongue, so as to gain a more extended attachment. The sections following this display an increasing quantity of this muscle, the diameter of the unbroken bundle in the centre being greater, and the fasciculi into which it divides at the sides more numerous ; but as yet no other system of fibres has appeared. The next addition, as we proceed backwards, is that of vertical fibres, which are at first very few and scanty, and placed not in the centre, but in two sets, one on each side of the centre ; they converge a little as they pass upwards, and are rather curved, presenting their concavity outwards. The succeeding sections show them increasing in numbers and spread-","page":1130},{"file":"p1131.txt","language":"en","ocr_en":"TONGUE.\t1131\ning towards the centre, where they finally meet, and then the central part of the tongue is constituted in the same way as it is throughout the whole succeeding length of the organ, namely, by decussating vertical and transverse fibres ; but as yet no longitudinal fibres have appeared, and they are not seen till after the transverse area of the tongue has been entirely occupied by the vertical and horizontal fibres as above described. They first appear at the inferior surface, then at the sublateral and lateral regions ; next they are seen at the centre of the upper surface in a small definite cluster, from which they spread out, and so complete the circumference of the tongue.\nWe see from this that the fibres that occupy the extreme point of the tongue are the transverse; that the next met with are the vertical ; and that the longitudinal do not extend so far forward as either of the other two. This is what might be expected. The chief muscular requisition at the extremity of the tongue is the power of pointing it : the shape of a tactile part is eminently subservient to its power of touch, because exact localisation, which is a most important element in touch (if it is not the very essence of it), depends on the smallness of the touching part. Now the extremity of the tongue, of its ordinary broad, flat shape when at rest, would be a very poor tactile instrument, and very far removed from a form that would capacitate it for the minute appreciation of distance and form. In what way, then, is the desired pointed shape of the tip of the tongue to be produced ? Manifestly by transverse contraction, for it is by the spread of the tongue in this direction that it departs from the pointed form ; and so we see the transverse fibres continued beyond either of the others, and occupying at the extreme tip the whole of the space assigned to the muscular structure. Furthermore, the longitudinal fibres are not necessary at the extreme point, either to flatten or shorten the tip, which is brought about by its own elasticity immediately on the cessation of the contraction of the transverse fibres, or to move it in any direction, which is done rather by the movements of the parts coming immediately next the tip than of the tip itself Thus, both negatively and positively, we see a reason for the continuation of the transverse fibres further forwards than either of the other two sets.\nThe section last described completes what may be called the theoretical structure of the tongue (it is shown in fig. 748., in one half of its extent) : the next change is one of infraction of that completeness of muscular structure, occasioned by the entrance of the genioglossi muscles on the inferior surface, whereby the continuity of the cortical layer is isolated, there being no discs in the space occupied by the immergence of these two muscles. The subsequent changes in the appearance of successive sections, are just such as might be expected from the description al-\nready given of such sections when viewed by the naked eye ; therefore, for the sake of brevity, I shall not here advert to them.\nA longitudinal vertical section, of course, displays a reversing of the position in which the discs and profile interlacement are respectively seen ; the discs are here in the central part instead of in the cortical, being the transverse fibres cut across ; the cortical layer is free from discs (except where, from the vertical and longitudinal fibres being oblique, they are obliquely cut), and is occupied by the longitudinal and vertical fibres, both seen in profile.\nA horizontal section displays very much the same appearance as the last : the discs are in the central part, and there is an absence of them in the circumferential portion; but in this case the discs are of the vertical fibres, in the other they were of the transverse.\nSuperficial sections, or sections made obliquely, I shall not attempt to describe; by such means the appearances might be infinitely varied, but their description would merely tend to confusion.\nFrom the above account it is seen that the microscopical investigation of the subject not only confirms and proves the conclusion arrived at by other means, but adds many new and interesting facts, and supplies us with one more instance of that contrivance and adaptation of means to end that meets us at every point.\nI have entered rather fully into the intrinsic muscular arrangements of the tongue, because there is no good account of the subject, that I can find, in the English language, nor of the appearances as seen by the microscope, in any language ; and I considered such an account a desideratum.\nMode of termination of the intrinsic fibres. \u2014 All the intrinsic fibres of the tongue, and indeed, it may be said, almost if not quite all of the extrinsic too, terminate by becoming inserted into the cutis \u2014 the sub-mucous fibrous tissue \u2014 which is extremely dense and thick, particularly on the upper surface. The transverse and vertical fibres pass direct to the cutis ; the longitudinal all ultimately have a similar insertion. In vertical sections the fibres may be seen passing up or down to the surface, and entering the cutis, which having pierced for a certain extent, they terminate : \u2014 some of them end just as they enter the fibrous tissue ; some of them may be traced quite up to the papillae.\nIt might naturally be expected that the muscular fibres of the tongue would, from their isolation, present great facilities for seeing the mode of the termination of muscle in fibrous tissue ; and indeed this is the case in a remarkable degree ; they seem to furnish the great desideratum of a natural isolation of the individual fibres, at the point where you are sure of seeing their union with the fibrous tissue that forms their means of attachment. As the opinions that 1 have come to from my own observations differ from those that are the result of some of the best researches on","page":1131},{"file":"p1132.txt","language":"en","ocr_en":"1132\nTONGUE.\nthe subject that have been made, namely those of Mr. Bowman, as published in the \u201c Philosophical Transactions,\u201d and in the \u201c Physiological Anatomy \u201d of himself and Dr. Todd, I would advance them with diffidence, and something like hesitation. The appearances that I have invariably seen, by daily examinations for some time, of sections from many tongues, is this: each fibre, before its termination, gradually tapers, in a fusiform manner, with more or less of acuteness ; sometimes the tapering is rather sudden, in other cases very much prolonged (fg. 752. a) ; in all the tapering is con-\nFig. 752.\nA. Fasciculus of the vertical fibres of the tongue, showing their fusiform extremities and the termination of each muscular fibre in a filament of white fibrous tissue. (Magnified 100 diameters. B. Magnified 200 diameters).\ntinued so far that the muscular tissue becomes nearly as fine as the fibrous tissue in which it terminates : from this fine extremity the fibre passes off', and the appearances at the point of transition are of two sorts ; the one as seen at b, a, where the muscle passes smoothly off in the fibrous tissue, and you cannot tell where the one commences and the other ends ; the other as seen at b, b , where the pointed extremity of the muscle is a little rounded, and its outline plainly visible ; but in this case, also, the diameter of the extremity of the muscle as nearly as possible coincides with that of the fibre. It is possible that the difference of appearance may depend in some degree upon difference of focus, but, certainly, I have not been able, in some cases, by any adjustment of focus, to get a clear definition of the point where the muscular structure terminated. In those cases where the outline of the termination of the muscle is defined, the transverse striation may be traced up to its very extremity ; where the outline of the one merges in that of the other, the striae seem also gradually to be lost, becoming a linear series of little dots, and so fading away (b, a).\nThe conclusion that the appearance at once suggested to me was, that the sarcolemma, condensed by the diminution of its contents, passed off from the acuminated extremity as a tendon of white fibrous tissue ; and this opinion was confirmed when I thought of the genesis of these structures. If, as seems probable from the account given by Schwann and other physiologists of the development of muscle, the sarcolemma is the persistent cell-wall of the original formation-cells of the fibre, and if white fibrous tissue is true zellenfasern \u2014 altered cell-wall of cells that have become elongated at their opposite nodes, and plicated as it were, \u2014 then we reduce the sarcolemma and the white fibrous tissue to the same category \u2014 altered cell-wall. The function of the cell-wall of the muscle-cell is to secrete that peculiar matter within it w'hich ultimately becomes sarcous matter ; the function of the cell-wall of the fibre-cell is to become elongated and plicated, or otherwise longitudinally striated. To explain, therefore, the gradual passage of one structure into the other, we have merely to suppose, on the part of the cell-wall, the gradual mergence of one function, and taking on of the other. These considerations at any rate tend to obviate any antecedent objections to the opinions suggested by the appearances, that would have arisen if there had been any thing essentially heterogeneous in the nature of the structures concerned. The fact, that Mr. Bowman\u2019s observations were made on the lower animals \u2014 fish, Crustacea, and insects \u2014 may perhaps account for the difference of the appearances. It is a subject that requires more investigation, and no structures seem to me so much adapted for this purpose as the tongues of the lower vertebrata.\nh. Extrinsic muscles of the tongue. \u2014These are four in number, the palatoglossus, the styloglossus, the hyoglossus, and the genioglossus; attaching the tongue to the soft palate, base of the skull, hyoid bone, and lower jaw, and moving it nearly in the four cardinal directions, upwards, downwards, backwards, and forwards. They are all more or less of a mixed nature, being continued in some degree into the tongue. They move the organ en masse, and attach it to distant parts by virtue of their extrinsic portion ; they contribute to the substance of the organ, and affect its form, by virtue of their intrinsic portion. It is this continuity of the substance of the tongue with its means of connection to distant parts that makes those connections so strong and safe ; it is this prolongation of the extrinsic muscles into the tongue that renders the association of the extrinsic and intrinsic movements so intimate.\nThe palatoglossus (glosso-staphylinus), the smallest of these muscles, constitutes the connection between the soft palate and the sides of the tongue. At its origin in the soft palate its fibres are mingled with those of the palatopharyngeus ; as it descends to the tongue it becomes much narrower, constitut-","page":1132},{"file":"p1133.txt","language":"en","ocr_en":"TONGUE.\t1133\ning the anterior pillar of the fauces ; and arrived at the sides of the tongue, it again spreads out, and its fibres mingle with those of the styloglossus, some of them passing transversely into the medullary structure. It lies immediately beneath the mucous membrane, and in front of the tonsil. Action : To constrict the fauces (hence its name, constrictor isthmi faucium) by depressing the soft palate and raising the sides of the tongue.\nThe styloglossus. \u2014 A small slender muscle arising by a pointed tendinous origin from the inferior half of the styloid process of the temporal bone, and also slightly from the stylomaxillary ligament. It passes downwards and inwards to the base of the tongue, opposite to which it expands and becomes flattened ; a few of its fibres bend inwards, the majority being continued longitudinally along the side of the tongue, where they may be traced to near the apex, contributing to the formation of the lateral lingual muscle. As they pass forward, they mingle with those fibres of the hyoglossus that have a similar direction, and with the inferior lingual. Relations: Externally, with the parotid and submaxillary glands, the external carotid artery, the facial artery, the Whartonian duct, the lingual branch of the fifth nerve, and the stylomaxillary ligament ; internally, with the stylohyoid ligament, internal carotid, superior constrictor of the pharynx, the jugular vein, and hyoglossus muscle. Action: To retract the tongue, to raise and expand its base, and to render it concave from side to side by raising its borders.\nThe hyoglossus.\u2014 Flat, thin, and ascending nearly vertically, this muscle approaches a quadrilateral form ; but, from the dorsum of the tongue ascending as it passes forwards, its anterior border is much larger than its posterior. It arises from the posterior extremity, and from the superior border and outer surface of the greater cornua of the os hyoides, and from the body in their immediate neighbourhood. From this double origin the fibres ascend in two distinct sets. Those from the greater cornua, passing up nearly parallel to one another, are inserted into the sides of the tongue; those from the body expand as they ascend, arch forwards, and, gaining the side of the tongue at a point superior and anterior to the other, pass forward along the border of the tongue, and unite with the styloglossus to form the lateral lingual. These two portions are separated below by a cellular interval ; and above a few fibres of the styloglossus pass in between them. Al-binus has described these as three distinct muscles : one, the cerato-glossus, arising from the greater cornua ; another, the basio-glossus, from the body : and a third, intermediate, the chondro-glossus, taking its origin from the lesser cornua. Relations : The external relations of this muscle are, \u2014 from above downwards, with the submaxillary gland, the hypoglossal nerve, the mylohyoid, stylohyoid, and digastric muscles ; internally, it covers the glosso-pharyngeal nerve, the middle\nconstrictor of the pharynx, the lingual artery, the stylohyoid ligament, the geniohyo-glossus, and, at its attachment to the tongue, the inferior lingualis, which separates it from the last mentioned. Bichat erroneously states that the lingual artery ordinarily passes between its two origins. Action : To depress the sides of the tongue and render its dorsum convex ; to retract the tongue and draw it downwards. It is more frequently associated with other muscles than isolated in its action ; and accordingly as it acts alone or together with other muscles, either as concurring with them or antagonising them, so its actions vary.\nThe genioglossus, the largest of all the muscles of the tongue, which it connects to the lower jaw, is of a radiated or fan-shape, and is placed vertically in immediate contact with its fellow of the opposite side. It arises from the superior genial tubercle of the lower jaw by a tendinous tuft from which the muscular fibres radiate to their different destinations. The most anterior, the shortest, forming the anterior free margin of the muscle, pass upwards and forwards to the tongue, having reached the under surface of which, they are continued, according to Cruveilhier, on that surface to the tip ; but in all the specimens that I have examined they appeared to continue an oblique course to the dorsum. The succeeding fibres pass more and more backwards, and having reached the inferior surface of the tongue, are directed vertically to the dorsum, into the middle line of the whole of which they are inserted, from apex to base. The two muscles may be separated up to the point of their immergence into the tongue, but beyond that line their separation is no longer possible ; for, having entered the tongue, they come into relation with the transverse intrinsic fibres, which they cut at right angles, and interlacing with which they pass to the cutis of the dorsum, forming part of the vertical intrinsic muscle, from the rest of which they are not to be distinguished except by their mesial situation. The fibres do not curve outwards, as supposed by Marjolin, to form part of the transverse lingual ; nor do they expand at all at their insertion, as stated by Cruveilhier ; there is no disposition to lateral divergence in any part of their course ; on the contrary, their direction is rather upwards and inwards throughout, and their insertion extremely narrow \u2014 a mere line \u2014as it might be imagined it would be, when its great longitudinal extent is remembered. The longitudinal furrow is, I think, mainly produced by the traction of this muscle in the median line. The most inferior fibres pass backwards and downwards, and are inserted into the hyoglossal ligament. Some of the fibres immediately above pass backwards, according to some authors, to the sides of the pharynx, where, uniting with the middle constrictor, they form the genio-pharyngiens of Winslow. Relations : Internally with its fellow, being separated merely by areolar tissue con-","page":1133},{"file":"p1134.txt","language":"en","ocr_en":"1134.\nTONGUE.\ntaining some fat, particularly at its inferior part and the median fibrous lamina, when the intermuscular areolar tissue is sufficiently dense to deserve that name ; anteriorly, with the fr\u00e6-num, to which it is subjacent; inferiorly, with the geniohyoid; and externally, with the sublingual gland, the mylohyoid, hyoglossus, and inferior lingualis muscles, the ranine artery, and the gustatory nerve. The hypoglossal nerve threads its fibres, and passes forwards among them. Action : To raise and draw forwards the tongue ; to assist in constricting the pharynx ; to protrude, retract, or depress the tongue in the mouth, according as all or part of the fibres are employed ; to depress the centre of the tongue, and render it concave, from side to side.\nc. Accessory extrinsic muscles. \u2014 These are, in short, all the muscles that move the os hyoides without being attached to the tongue, for whatever moves the hyoid bone must move the tongue, which is fixed to it. They are accessory to theproper extrinsic muscles in two ways, either by acting in concert with them, or by facilitating their action on the tongue by rendering the hyoid bone a fixed point. Thus, in the first method, the stylohyoid and posterior belly of the digas-tricus concur with the styloglossus in drawing the tongue upwards and backwards. In the same way, the anterior belly of the digas-tricus, the mylohyoid, and geniohyoid, concur with the inferior portion of the genio-glossus in raising and drawing forwards the hyoid bone, and facilitating the protrusion of the tongue from the mouth. By the second method the muscles from the styloid process to the hyoid bone assist the longitudinal intrinsic muscles of the tongue by rendering the base a fixed point from which they can advantageously act on its length, and in the same way the inferior set of hyoidean muscles are accessory to the hyoglossus by fixing the hyoid bone down. More might be said on this subject, but enough has been stated to indicate the important relation of these muscles to the proper muscles of the tongue, and for the sake of brevity that may suffice.\nMovements of the tongue. \u2014 All the infinite variety of movements by which the tongue is, by virtue of its complex muscular organisation, susceptible, may be arranged under two heads, \u2014 its extrinsic and intrinsic movements ; sometimes dissociated, more frequently concurrent : for the sake of clearness I shall consider them separately, and then group them.\nFirst, the intrinsic movements of the tongue are of two sorts ; those affecting its length, and those affecting its direction.\na. As affecting its length. The elongation of the tongue is provided for, like all intrinsic elongation, by diminution of calibre ; in the tongue this is produced by transverse and vertical contraction, especially the transverse, whereby the tongue becomes at once elongated and pointed ; by this means the tip of the tongue can be protruded beyond the teeth without any movement of the organ en masse,\nor any assistance of the extrinsic muscles. From this elongated state it is restored to its original position and shape by the contraction of all the longitudinal fibres composing the cortical portion, which draw it directly back, the transverse and vertical fibres at the same time ceasing to act. Thus we see that the central and cortical portions of the intrinsic muscles are antagonistic ; but they are capable of association : for instance, when the tongue is to be flattened and its sides pressed against the teeth without any elongation, an action very frequent in mastication and in the pronunciation of some letters, this is done by the contraction of the vertical fibres associated with the longitudinal, the one diminishing the vertical thickness, and so spreading the tongue out, the other preventing the elongation which the diminution of vertical thickness would otherwise be attended with.\nb. As affecting its direction. The direction of the tongue is entirely regulated, as far as the intrinsic muscles go, by the longitudinal fibres, and their power of modifying the direction of the tongue, as well as shortening it, depends on their power of partial action : thus the lateral lingual of one side can act, or of the other ; the superior or the inferior, and the point of the tongue is of course moved to the side of the acting muscle. This modification of the direction of the tongue is, perhaps, the most complete movement that it possesses ; it is certainly the most extensive : by it the tip of the tongue may be depressed deep below the incisor teeth, or reflected back on the soft palate, so as nearly to touch the uvula; or laterally, from the pillars of the fauces on one side it may be carried round the cheeks and alveolar arches to the same position on the other side : these are the cardinal points, up and down, right and left; they may be united in any proportions, so as to carry the extremity of the tongue to any intermediate position.\nMoreover, the movements affecting the length of the tongue may concur with those affecting its direction ; for instance, on applying the tip of the tongue to the root of a canine tooth of the upper jaw, on the outer surface of the alveolus, the tongue is elongated, and vertico-laterally flexed; on applying it to the last molar tooth of the lower jaw it is laterally flexed and shortened.\nSecondly, the extrinsic movements of the tongue admit of the same division as the intrinsic, into those regulating its length, and those regulating its direction or shape.\na.\tThus the tongue is carried upwards and backwards by the styloglossus, assisted by the other styloid muscles, downwards and backwards by the hyoglossus, directly backwards when these both concur; and it is carried forwards and protruded from the mouth by the genioglossus. These movements, en masse, almost always concur with the intrinsic movements, the whole organ following to a certain extent the direction of the extremity.\nb.\tBut the extrinsic muscles affect very","page":1134},{"file":"p1135.txt","language":"en","ocr_en":"1135\nTONGUE.\nmaterially the direction and shape of the tongue: the styloglossi raise and expand the sides, the palatoglossi raise and approximate them, and the hyoglossi depress them; the one set makes the dorsum of the tongue transversely concave, the other convex : moreover, the posterior fibres of the genio-glossus draw the centre of the tongue forwards and downwards, so that they also render the tongue transversely concave. The action of the genioglossus is peculiar ; the most posterior fibres draw forwards the base of the tongue, and are those chiefly concerned in the protrusion of the organ ; the most anterior concur in replacing the tongue when thus protruded ; when the whole muscle acts it compresses the tongue into a sort of button, and carries it deep down in the arch of the lower jaw. The relations of the hyoglossus and genioglossus are worthy of remark : they are congeners, inasmuch as they both tend to draw the tongue downwards ; they are antagonists, inasmuch as the one tends to draw the tongue principally forwards, the other principally backwards ; when all four muscles act, the tongue is depressed deep in the jaw, but further back than when the genioglossi act alone ; when the two muscles of one side act, that side alone is depressed, and a certain torsion is given to the tongue which enables it to \u2018apply the tip advantageously to parts that it would otherwise be very difficult to reach. If the movement of the tongue in transferring the tip from the last inferior molar tooth of one side to that ofthe other be watched, with the mouth open, at a glass, it will be seen to be collected in a globe at the back of the mouth, and to rotate horizontally, as it were on a pivot. The only way in which I can conceive this movement to be brought about, is by the consentaneous action of the hyo-glossus of the one side with the genioglossus of the other,\u2014the one right with the other left, then the one left with the other right, and so on, the styloglossi and palatoglossi at the same time preventing the depression of the tongue.\nBut it would be vain to attempt to describe in words the endless variety of movements of which the tongue is susceptible ; and if it were possible to give an idea of them, space could not be afforded: so, dismissing this part of my subject, I will proceed to the next.\n3. Tegumentary system. \u2014 The tegumentary system of the tongue is formed by the mucous membrane of the mouth passing on to it from neighbouring parts, and undergoing special modifications according to the part that it invests. A superficial glance shows it at once to admit of a triple division, into, first, a really or apparently plane portion, situated in front of the epiglottis, beneath the borders, and on the free portion of the under surface ; secondly, a papillary portion, covering the anterior two-thirds of the upper surface, the free borders, and the tip ; and, thirdly, a glandular portion, occupying the posterior third of the upper surface, where it is folded\ninto little crypts and raised in nodules over small mucous glands : these glands exist also along the sides and beneath the tip : they will be reserved for future description.\nThe mucous membrane here, as elsewhere, consists of three portions, \u2014 a basement or limitary membrane, underlaid by a submucous areolar tissue, and surmounted by an epithelium.\na.\tCutis.\u2014The sub-basement areolar tissue of the tongue exists in sufficient quantity and density to deserve the name of a true chorion or cutis. It is thickest at the upper surface, where it underlays the papillae, especially towards the median line; its density too is the greatest here, sometimes amounting to almost a cartilaginous hardness, and the proportion of white fibrous tissue to the yellow is the greatest ; it is thinnest on the under surface and edges, where it contains more of the elastic element, especially in the neighbourhood of the epiglottis ; at the line where the attached and free portions of the tongue meet, it gradually merges off into the loose elastic web that underlays the mucous surface in these situations. Its inner surface receives the insertion of all the intrinsic muscles of the tongue, among which for a short distance it dips, and it sends processes into the folds that attach the tongue to neighbouring parts, as the glosso-epiglottidean and fr\u00e6num. It is the medium in which the nerves and vessels destined to the surface break up previous to their ultimate distribution : the vascular ramifications form a plane network, coincident with the surface, from which, at regular intervals, the papillary vessels ascend.\nb.\tThe basement membrane is variously modified in the three situations above indicated; it is either continued plane, projected into papillae, or folded into mucous crypts, from which its further involution constitutes the minute ducts and ultimate follicles of the mucous glands opening into these crypts : its description will be involved in the particular consideration of these structures.\nc.\tEpithelium.\u2014This very nearly approaches in character the cuticle of the skin, which it resembles in being of the scaly variety, in the amount to which it exists, and in its being divisible into two layers, a deep one closely adherent to the basement membrane, consisting of more recent cells, retaining much of the cellular form {fig. 753., c.), and a superficial one, readily desquamating, the cells of which are older and flattened into scales {fig. 753.. d.). It exists in very different quantity in different parts, being most abundant where it invests the papillary structures. The shape of the individual cells is very various ; where they are flattened their area is much extended {fig. 753., a.), and they look four or five times as large as the deep-seated ones ; but probably there is no increase in size, their lateral extension resulting from their greater thinness: viewed in profile they appear quite filamentary ; some of them are not flattened but elongated, so that they appear linear in all aspects, and are really so. In spite of all these modifications","page":1135},{"file":"p1136.txt","language":"en","ocr_en":"TONGUE.\n1136\nFig. 753.\nEpithelium, of the tongue, a a single flattened superficial cell, viewed super-\u2019 ficially and edgewise ; b, from the horse, showing the filamentary prolongation of a part only of each cell ; d, superficial ; c, deep layer.\na small single circular nucleus may generally be seen very plainly occupying a central position in the cell, and unchanged in form and size by any of the changes that the cell undergoes. Certainly the epithelium, covering most parts of the tongue, does not contain any pigment; but I think that covering the filiform papill\u00e6 in the centre of the dorsum very frequently does ; and for these reasons, because, first,\" the growth of the epithelium here is very abundant, and it seems a geneial rule that pigment should be associated with an abundantly nourished or rapidly developed epidermis, as is seen in hair, in the colour of those spots that are called moles, and the hair that proceeds from them, which, instead of being invisible, as in neighbouring parts, is dark and rank, and in the change of colour which the cuticle and hair covering the parts of generation undergo at the increase of the nutrition of the parts that accompanies the accession of the generative function ; secondly, because we see that the epithelium does undergo great changes of colour, being generally darkest when most abundant; thirdly, because, m two cases that I have seen, in which the only diseased condition was an enormous development of the filiform processes which the epithelium forms in the centre of the tongue, the colour of the fur was a dark sepia or Vandyke brown, almost black, exactly that of pigment in other situations: we see too, when the epithelium has been lendeied opaque by soaking the tongue in alcohol, that all the other papill\u00e6 are whiter than the filiform occupying the centre of the dorsum, which retain their tawny colour. The epithelium of the tongue differs from the dermic cuticle chiefly in its moisture, and the delicacy and softness of its structure.\nPapillary structure of the tongue. \u2014 The papill\u00e6 of the tongue are generally contrasted with those of the skin, in that while the latter are covered over with an even layer of epidermis, and therefore not visible to the naked eye, the latter stand out free from the surface of the epithelium, dipping down between them. But viewed by the light of recent researches, this is seen to be only the apparent difference, the real difference being that while the papill\u00e6 of the skin are sessile, the\npapill\u00e6 of the tongue are arranged in groups on proper pedicles or supports, whose tops and sides they cover, and which elevate them above the general surface. For it has been recently shown by Professors Todd and Bowman *, that the papill\u00e6, heretofore considered simple, are really compound organs, and that they are covered by other smaller papill\u00e6, whose form and whose method of nervous and vascular supply, show their true analogy to the papill\u00e6 of the skin. In physiological exactness, and to carry out the analogy instituted by these anatomists, we may say that these large papill\u00e6, so called, are no more true papill\u00e6, than the long processes in the intestine of the rhinoceros are true villi. Now, these secondary, or true physiological papill\u00e6, are covered in by an even layer of epithelium, in just the same way as the papill\u00e6 of the skin ; hence we see that the distinction generally laid down ceases. It would, however, be too great an innovation to reject the name of papill\u00e6 for those organs that have so long possessed it, and as the value and office of their different parts will be implied in their description, no misconception can arise. I shall, therefore, continue the old nomenclature.\nThere are three principal forms under which the papill\u00e6, visible to the naked eye, exist on the surface of the tongue. 1st. The circumvallate (caliciform, Cuv.), the largest and fewest in number, and the most conspicuous, situated at the junction of the middle and posterior third of the tongue, where, by their arrangement in two lines, having a direction backwards and inwards, which meet in the centre, they form a V-shaped ridge, with the base directed forwards ; 2nd. The fungiform, more numerous than the last mentioned, and smaller, irregularly scattered over the centre, sides, and apex of the tongue ; and, 3rd, The conical or filiform, by far the most numerous and smallest, arranged in a dense pile over the w hole anterior two-thirds of the upper surface, among which the last-mentioned are implanted. To these may be added a fourth class of simple sessile papill\u00e6, first pointed out by Professors Todd and Bowman as existing on the apparently non-papillary surface immediately behind the circumvallate papill\u00e6, and which I have found also to exist on the whole of the under surface of the free portion of the tongue.\nThe circumvallate papill\u00e6 are of the most complex form, and may be considered as consisting of two parts \u2014 a central, button-like projection, flattened or truncated at its free surface, and a raised border surrounding it in the form of a ring, of nearly equal elevation with the central part, the two portions being separated by a circumvallation, or fossa (If). When a vertical section is made of one of these papill\u00e6 (fig. 754.), the central portion is seen to be in the form of an inverted cone, and the surrounding fold is seen to constitute a cup, at the bottom of which the apex of the\nPhysiological Anatomy, vol. i, p. 435.","page":1136},{"file":"p1137.txt","language":"en","ocr_en":"TONGU\u00cb.\n1137\nFig. 754.\nCircumvallate papilla seen in vertical section, a, Truncated surface, or base of tbe cone; b, cir-cumvallation ; c, raised border. (Mag. 16 diam.)\ncone is attached. At the attached portion the nerves and vessels enter, and the free truncated surface, or base, of the cone is covered with small secondary papill\u00e6, concealed by the epithelium (fig. 754. a) ; the free border is also surmounted by secondary papill\u00e6, so that it is, in fact, a circular compound papilla (c). The circumvallate papill\u00e6 possess the utmost irregularity as to size, number, shape, and arrangement. Their number has been much overstated by some anatomists ; Cruveilhier gives it as from sixteen to twenty, Marjolin from nine to fifteen, Soemmering from twelve to fourteen, and Meckel from three to twenty. I think the number given by Messrs. Todd and Bowman, as from eight to ten, is much nearer the truth ; certainly, if ten can be counted, they must be considered well deve* loped ; frequently the number is below this \u2014 I have seen as few as five, or even four. In size they vary from that of an ordinary fungiform papilla to upwards of \u00a3th of an inch in diameter. They always assume more or less of the V-shaped arrangement, but the perfection with which the linear series is maintained, the straightness of the lines that form the angle, and the size of the angle so formed, all vary very much ; I have seen them stretching across from side to side of the tongue, almost in a straight line, with a third arm projecting back from the centre, something like the form of a tripod ; it is not uncommon to find a stray one or two scattered to a great distance beyond the prescribed line ; the central one is frequently thrown back half an inch, and sometimes a lateral one is found\nquite at the edge of the tongue. In shape, the varieties are chiefly owing to the relative size and development of the central tubercle and the circular ridge surrounding it. Sometimes one of these parts is suppressed, and then you either get what appears to be a large fungiform papilla, or a set of ridges having something of a circular or quadrilateral arrangement, not to be distinguished from the fused rows of conical papill\u00e6 which surround the circumvallate on all sides, and which are, in fact, continuations and prolongations of their calices. Haller mentions having seen the circumvallate papill\u00e6 in two rows on each side ; I have met with a similar arrangement on one side. This appearance may in some degree be accounted for by the supposition that the rows of conical papill\u00e6, among which the large fungiform immediately in front of the circumvallate are planted, have attained a circular or calyx-like arrangement around them ; for a large fungiform papill\u00e6, situated in a calyx so formed, would produce a very perfect papilla circumvallata. This change is just the reverse of that which reduces a circumvallate papilla to a fungiform by the suppression of its surrounding ridge, and both, no doubt, are sources of irregularity. These papill\u00e6 are supplied by branches from the glosso-pharyngeal nerve, which may be distinctly traced to them ; their vascular supply is abundant, and their epithelium thin and fine, so that during life, and when injected, they appear very red.\nThe fungiform papill\u00e6, as their name indicates, have more or less of the form of a sphere supported on a pedicle ; this is their typical form, but they often deviate from it ; in size they vary from ^th to -J^th of an inch. They are scattered over the sides and tip of the tongue, and on the dorsum in front of the circumvallate. They may be distinguished from the filiform, among which they are implanted, by their red colour, in which, in the thinness and smoothness of the epithelium investing them, and in the abundance of their vascular and nervous supply, they resemble those last described. When examined microscopically, they are seen to be covered on their sides and summit with secondary papill\u00e6 (fig. 755. A), to\nFig. 755.\nA,\tFungiform papilla, showing the secondary papill\u00e6 on its surface, and at a the epithelium covering them over. (Mag. 35 diam.)\nB,\tAnother, -with the capillary loops of its simple papill\u00e6 injected, a, artery ; v, vein. The groove around the base of some of the fungiform papill\u00e6 is here represented, as well as the capillary loops, c c, of some neighbouring simple papill\u00e6. (Mag. 18 diam.) (After Todd and Bowman.)\n4 D","page":1137},{"file":"p1138.txt","language":"en","ocr_en":"TONGUE.\n1138\nwhich, in injected specimens, the individual loops of capillaries may be seen projecting with great regularity and beauty (B). The fungiform papill\u00e6 are largest about the centre of the tongue, smallest along the edges, and most numerous at the sides of the tip, but they are liable to the greatest variety in their size and distribution ; I have seen them so large about the centre of the tongue, as almost to equal in size the circumvallate ; I have seen them so numerous at the tip, as nearly to equal in number the filiform among which they were scattered ; again, in the same region, I have seen them so scanty, that they could hardly be said to exist there.*\nThe conical or filiform papill\u00e6, the third dass, constitute the great mass of the papillary structure ; they cover, in a close-set pile, the whole of the anterior two-thirds of the tongue, being limited behind by the circumvallate, and having the fungiform scattered among them : it is their structure that imparts the rough coriaceous character to the papillary surface, and they constitute the fur in the centre. They are altogether smaller, but in length they exceed, at least in the centre, the other two forms, and they exhibit greater diversity of structure and a more complete absence of typical shape than either of the other varieties. They affect in some situations a\nFig. 756.\nA filiform papilla taken from the dorsum of a tongue in which the fur was much developed. (Mag. 30 diam.')\na, imbricated scaly epithelium investing the cylindrical portion of the papilla; b, the commencement of its breaking up ; c, its separation into its ultimate filamentary processes ; d, the deep layer of epithelium exposed by the removal of the more scaly superficial one.\n* May not these varieties explain the corresponding diversities in the acuteness of the sense of taste, \u25a0which we so often find in different individuals ?\nlinear arrangement, principally at their confines, that is, in front of and around the caliciform papill\u00e6, where they are continuous with the elevations that surround these papill\u00e6, of which they are the continuations forwards and outwards, and along the whole free margin of the tongue, except at the tip, where the linear arrangement cannot be traced. In the first-mentioned situation their rows run forwards and outwards, coinciding with the*arms of the V-shaped figure that the circumvallate papill\u00e6 assume ; in the last-mentioned, they are placed vertically along the sides (fig. 745. i i) : they have been well described and figured by Soemmering.* Along the centre of the tongue, in the neighbourhood of the median furrow, the conical papill\u00e6 often assume a cracked and fissured appearance ; but the linear arrangement is less marked here, and the fissures have no determinate direction, but can be made and effaced according to the movements of the tongue. The conical papill\u00e6 are largest in the neighbourhood of the circumvallate, where they are truncated, and where some of them assume almost a fungiform shape : they are longest about the centre of the tongue, near the median line, and smallest in the anterior part, near the side and tip. The form of the projections of basement membrane, on which the epithelium is\nFig. 757.\n...\u00c6,\nVertical section of conical papill\u00e6. (Mag. 25 diam.') a, basement surface ; b, conical papilla of ordinary shape; c, more nearly approaching the simple form ; g, one quite simple ; e, deep cellular layer of epithelium ; f, superficial scaly portion ; h h, points from which the filamentary prolongations would have passed up.\nplaced, constituting the mould of the true papillary structure, is generally something of a cylindrical shape, the top supporting secondary papill\u00e6, or it is conical, the secondary papill\u00e6 being continued more or less down the sides : or the base is small, and supports a more expanded portion, and thus the conical is seen to pass into the fungiform shape. But it is in the epithelium that the characteristic difference between these and the other papill\u00e6\n* leones Organorum humanorum gustus et vocis. Francofurti, 1808.","page":1138},{"file":"p1139.txt","language":"en","ocr_en":"TONGUE\t1139\nis to be found. In the other forms we saw it continued over the whole compound organ as a thin indusium, covering in and concealing the secondary papillae under its smooth investment, the scales being arranged parallel to the surface ; but in the conical and filiform papillae we not only see the epithelium existing in much greater quantity, but over each secondary papilla assuming a vertical arrangement, and, after continuing compact for some little distance, breaking up into a brush of hair-like processes {fig. 756.), the number coinciding with that of the secondary papillae. Where the secondary papillae are few the hairs are few, where they are many the hairs are many, and each hair may be traced down, by following the line in which the epithelium is vertical, to each papilla. In fact, these processes are true hairs, and only differ from other hairs in being short, uncompact, imperfectly elaborated, and in having the imbrication retroverse instead of directed forwards ; and the secondary papillae from which they spring are true hair papillae, differing only from ordinary hair papillae in being raised and grouped on a common pedicle instead of sunk in a proper follicle. In some cases the resemblance of these filaments to ordinary hair is very close indeed, as seen in fig. 758, ; indeed in c\nFig. 758.\nHair-like processes of filiform papilles, a, Mag. 150, b and c, 100 diameters.\nthe chief difference is in the direction of the imbrication : in some morbid specimens I have seen it even closer.\nNow this difference in the arrangement of the epithelium on the different papillae indicates, I think, a very important physiological distinction ; in one case we see the sentient papillae covered by a thin layer of a fine epithelium, thinner over them than in the intervals between them ; in the other case we see each secondary papilla the seat of a rapid generation of epithelium that clothes the whole compound organ with a dense impenetrable brush of hairs : this latter arrangement\nseems as inconsistent with the possession of sensibility as the former seems adapted to it, and the difference would suggest to me the division of the papillae into \u201c sentient\u201d and \u201cprotective among the former I would class the circumvallate and the fungiform, among the latter the filiform and, with a certain qualification, the conical : but I shall return to this presently in speaking of the functions of these papillae. The great difference between the filiform and conical forms is in the amount of the epithelium : in the filiform it is such as has just been described j in the conical, the hairs are very short and thick, and terminate in an even plane almost as soon as they become separate, so that they have not at all a filamentary character. This epithelium is being constantly generated and as constantly thrown off, as is shown by the variation in the quantity offur on the tongue from day to day. It is in these papillae that the separation into two layers is best seen {fig. 757. ef ), and the appearances of this separation are such as to make me think that the method of desquamation is not by the shedding of individual scales, but by the throwing off of the upper layer, the under layer taking its place, itself to become divided into a deep-seated and superficial portion, and to be in turn thrown off as it grows older. The vascular supply of these papill\u00e6 is very abundant, as might be expected from the rapid nutrition that is taking place from their surface. The pigmentary character of the epithelium, at least under some circumstances, has been already referred to.\nThe simple papill\u00e6 are scattered beneath the apparently non-papillary surface behind the circumvallate, beneath the edges of the tongue, and on the under surface of its free portion, also among the conical and filiform ; in the former situation they resemble the secondary papill\u00e6 of the circumvallate and fungiform, in the epithelium being continued smoothly over them ; in the latter, those of the filiform, each being the base of a hairlike process. The situation of these papill\u00e6, their number and arrangement, is very well shown by injection, when the individual loops of capillaries may be seen passing up from the sub-mucous plexus at regular intervals, one to each papilla. The method in which the conical papill\u00e6 of the upper surface pass into the simple of the under, is this : \u2014 the ridges on the side of the tongue, to which reference has already been made, consist of fused conical papill\u00e6 arranged in linear series vertical to the edge, and, like them, crowned with secondary papill\u00e6 ; as they pass down the edge towards the under surface they become shallower, so that by the time they have reached that surface, the secondary papill\u00e6, instead of being elevated, are sessile, and immediately subtended by the cutis. This is the true nature of those vertical ridges on the edge of the tongue described by Bichat, Soemmering, and many other anatomists.\nStructure of papill\u00e6.\u2014 The nature of the true papillary structure, i. e. the contents of the projection of basement membrane, seems 4 v 2","page":1139},{"file":"p1140.txt","language":"en","ocr_en":"1140\nTONGUE.\nto be partly fibrous, partly granular : certainly something like yellow fibrous tissue can be detected, particularly on the addition of acetic acid ; but those specimens that I have examined have appeared to be more granular than fibrous, and in some cases, where there has been a fortuitous rupture of the papilla, there has been an abundant escape of a finely granular material : the exact nature of this granular material I have not been able to ascertain ; it is not fatty. The method of termination of vessels is sufficiently conspicuous, and has been already indicated. With regard to the termination of nerves I must confess, that, after long-continued and careful search, I have been unable to find any thing I can construe into a looped termination. I have traced the nerve for some little way into the simple papilla, and then, its outline becoming less and less definite, it has ceased to be visible, apparently from the loss of the strong refraction of the white substance of Schwann. If I might hazard an opinion, I should say that the axis was probably denuded of this investment, and, thus laid bare, underwent some specific peripheral modification. In a paper by Dr. Waller, recently published in the \u201c Philosophical Transactions of the Royal Society,\u201d a method of nervous termination by open mouths is suggested : considering the solid nature of the nerve-axis, this appears to be an opinion that requires either some modification, or the confirmation of repeated and varied observations, before it can be received as certain. At present our means of examining the termination of nerves, either in the organs of sense or elsewhere, are imperfect, and until they are less so we can hope to make but little advance in this, at present, obscure subject.\nFunctions of the different pap\u00efll\u0153.\u2014Three offices are to be discharged by the papillae \u2014 they are to exercise the sense of taste, the sense of touch, and to form a suitable clothing and protection to the tongue. The structure of the circumvallate and fungiform papillae, their shape, their position, the nature of their epithelium, all point them out as the organs that are to discharge the first-mentioned function, and their nervous supply, which may be demonstrated with facility, makes that probability a certainty. To detail the evidence on which this conclusion is based would merely be to repeat what the reader will find given at length under the \"articles Fifth Nerve, Eighth Nerve, and Taste, to which I therefore refer him. By what papillae,then, is the sense of touch exercised? I think by the conical, and by them in contradistinction to their non-gustatory congeners, the filiform. My reasons are, first, that the sense of touch is only possessed in any perfection by the papillae at the tip of the tongue.* Now\n* There can be no doubt about this fact ; and it is what we might antecedently expect, because it is the most movable part, and therefore has the w'idest range of application ; because it is the most capable of movement, and therefore the best adapted for that which is an essential condition of touch ;\nthese are conical and of the form the'most removed from the filiform type, that is, their epithelium is the least abundant of all the non-gustatory papillae. Secondly, because the structure of the filiform papillae is the most incompatible that could be devised for the possession of a sense of touch in any perfection. And, thirdly, because we do find, in fact, that the centre of the dorsum of the tongue, where the filiform papillae exist in the greatest abundance, is the least sensitive part of any. Therefore, unless we assign the sense of touch to the gustatory papillae, which the lowness of its condition at the back of the tongue, where the gustatory papillae are so abundantly developed, seems to negative, we are driven to the conical as the only ones that can possess it. The filiform papillae remain for the third office \u2014 that of clothing and protecting the exposed dorsum of the tongue ; their pilose investment admirably adapts them for this, and at the same time it imparts to the surface a certain prehensile power, enabling it to take hold of and move readily what is placed on it, while the backward direction of the hairs adds yet more a special facility for transmitting food towards the pharynx.\nMucous glands.\u2014These are largest and most abundant at the base of the tongue, where they occupy the space behind the circumvallate papill\u00e6, and lie immediately beneath the surface, which they raise in nodular eminences. The most anterior of them form a V-shaped ridge, the counterpart of that formed by the circumvallate papill\u00e6, from which they are separated by a corresponding furrow. These structures, which are true mucous glands, analogous to the buccal and labial, are of an oval or roundish lenticular shape : in front of the epiglottis they are gradually lost. Each gland is surmounted by a distinct orifice, most conspicuous in the most posterior of them, opening into a little crypt, generally closed and collapsed, but dilatable so as to be large enough to contain a mustard-seed, and into the bottom of these crypts the minute ducts of the glands open. Some of these crypts I have found extending into long and capacious canals, branching in different directions, and undermining the surface. I have traced some of them half or three-quarters of an inch before they have terminated in their blind extremities : their surface is quite smooth, and the orifices of the ducts of neighbouring glands might be seen terminating in different parts of it. They probably act as reservoirs, and permit some accumulation of the secretion, and also prevent the orifices of the glands from infarction by the matters passing over the surface. Similar glands, but smaller, are seen along the sides of the tongue, particularly near the base ; and under the tip a small aggregation of them,\nbecause we find it is the tip that we do apply to parts that we want to feel ; because the tip is capable of receiving a pointed form, and therefore localising the impression more perfectly; and because the tip receives the most abundant supply of twigs from the fifth nerve.","page":1140},{"file":"p1141.txt","language":"en","ocr_en":"1141\nTONGUE.\nfirst described by Nuck, may generally be detected : they are about eight or ten in number, much smaller than those at the base, situated on each side of the median furrow, and each surmounted by a little orifice. The true glandular nature of all these structures is proved by microscopical examination : they are seen to be true conglomerate glands, their ultimate follicles filled with an abundant secreting epithelium.\nVessels of the tongue. \u2014 The vascular supply of this organ, which is large in proportion to its size, is derived mainly from its proper artery, the lingual, but it receives some small branches at its sides and base from the inferior pharyngeal and palatine. The lingual artery arises from the external carotid, between the inferior thyroid and the facial : it passes upwards and inwards, at first superficial, covered only by the integument and fasciae, to reach the posterior border of the hyoglossus muscle, beneath which it passes to its anterior border, where it breaks up into its terminal branches, the sublingual and the ranine. In the first part of its course it lies on the middle constrictor of the pharynx ; in the second part it is covered by the hyoglossus and mylohyoid muscles, and lies on the middle constrictor and genio-glossus. Previous to passing beneath the posterior border of the hyoglossus the artery is crossed by the hypoglossal nerve, which, at first placed below it, now rises above it ; the hyoglossus muscle then separates the two, the nerve lying outside of it and the artery beneath it, but at its anterior border they are again in relation ; the nerve, however, is now inferior, having crossed the course of the artery while beneath the hyoglossus. Its branches are, 1st, a hyoid branch, passing along the upper margin of the hyoid bone, corresponding to a branch of the superior thyroid running along the under margin of the bone, with which and with its fellow of the opposite side it anastomoses ; 2dly, the dorsalis lingu\u0153 branch, ascending from the artery in the second part of its course, supplying the side and dorsum of the tongue ; 3dly, the sublingual, one of its two terminal branches, passing downwards and outwards from the anterior margin of the hyoglossus to be distributed to the sublingual gland, cellular tissue, and mucous membrane adjacent ; 4thly, the ranine, which may be regarded as its continuation, passing upwards and inwards in immediate relation with the genioglossus to the tip, where it anastomoses with its fellow. That the communication of the arteries of the opposite sides of the tongue is not very free, is shown by the imperfect injection of one side when the injection is made into the carotid of the opposite side : it is free enough, however, to make the ligature of the artery of one side of little service in stopping haemorrhage of that side, the supply from the other being sufficient to keep it up.\nNerves of the tongue. \u2014 The tongue is supplied with nerves from three sources, two sentient\u2014 the lingual branch of the fifth, and the glosso-pharyngeal, and one motor \u2014 the\nninth or hypoglossal nerve. The lingual or gustatory nerve, one of the three great branches into which the sensory portion of the inferior maxillary division of the fifth breaks up after its emergence through the foramen ovale, passes down, at first between the external pterygoid muscle and the small muscles of the palate, then between the two pterygoids, then between the internal pterygoids and the jaw, finally escaping from between these two at the anterior border of the muscle ; it then runs downwards and forwards, under the protection of the jaw, to the side of the tongue, crosses the mylohyoid attachment of the superior constrictor, then passes forwards beneath the sublingual gland and to the outer side of the ranine artery, to terminate at the tip of the tongue. The numerous small branches that are distributed to the conical and fungiform papillae may be seen ascending from the nerve whilst beneath the tongue, passing upwards and forwards through the substance of the organ to the mucous surface. The other nerve of sensation, the glosso-pharyngeal, the smallest and most anterior division of the eighth pair, emerges from the skull through the foramen lacerum jugulare by a distinct fibrous canal ; it then descends between the jugular vein and internal carotid, passing forwards, in front of that artery and beneath the styloid process and muscles arising from it, to the anterior border of the stylo-pharyngeus, between that muscle and the styloglossus ; it then passes under the hyoglossus, beneath which and below the tonsil it divides into its branches for the supply of the gland and the tongue : its arch across the neck is below that of the lingual, and above the hypoglossal, but deeper seated than either. The branches to the tongue are distributed to the circumvallate papillae, and the mucous surface behind them. The ninth, or hypoglossal nerve, the motor nerve of the tongue, after escaping from the skull through the anterior condyloid foramen, lies at first deep, between the internal jugular vein and carotid artery ; coming forward between them it becomes superficial, and forms an arch across the neck below, and parallel to, the digastric muscle, hooks round the occipital artery, and passes beneath the mylohyoid muscle, but superficial to the hyoglossus, at the anterior border of which it pierces the fibres of the genioglossus, and divides into its branches for the supply of this and the other muscles of the tongue : its relations to the lingual artery have been mentioned. For a more detailed account of these nerves, of their relations, branches, and the experiments on the results of which the present amount of our knowledge as to their function is based, the reader is referred to the articles Fifth Nerve, Eighth Nerve, Ninth Nerve, and Taste.\nComparative Anatomy. \u2014 The first indication that we find of any thing that can be construed into a tongue is met with in the Articulata, and, among them, in Insects. Its claim to the name is a matter of doubt 4 d 3","page":1141},{"file":"p1142.txt","language":"en","ocr_en":"1142\nTONGUE.\namong naturalists*; but since a certain oral appendage, at least in some of the orders, has received by common consent the name of lingua, I shall briefly describe it. The mouth of insects is furnished with two lips \u2014 an upper lip, or labrum, and a lower lip or labium ; besides four jaws \u2014 a mandible,\u2019 or upper, and a maxilla, or lower jaw, on each side. The labium, or lower lip, is divisible into two parts \u2014 a mentum, or basal joint, and a more flexible piece moving on this, the ligula, or labium proper. On the inner surface of this labium is developed a small process having a certain resemblance to a tongue, situated in front of the oesophageal orifice, and generally anchylosed with the labium at the front and sides of that opening ; in some cases, however, as in the locusts and dragonflies, it is free. This process Cuvier considered merely as a part of the labium, and accordingly called it labium; Fabricius and Latreille gave it the name of ligula. In shape it is generally short, but in bees it is long ; it is frequently simple, but in the wasp its apex is trifid, the same in Melolontha stigma; in Canobus it possesses three short teeth ; in Elaphras it terminates in a single tooth or point. In substance it generally approaches to a cartilaginous consistence, but in the Ortho-ptera and Libellul\u00e6 it is much more fleshy : and in the predaceous beetles it is as hard and horny as the integument. In some cases it is immovable, in others projectile and retractile within the mouth ; in some cases smooth, in others covered with hairs, as is the case in the common hive-bee ; in Melolontha stigma the hairs are incurved- In the hive-bee the upper part of the tongue is cartilaginous, and remarkable for a number of transverse rings : below the middle it consists of a membrane longitudinally folded in inaction, but capable of being inflated to a considerable size : this membranous bag receives the honey which the tongue, as it were, laps from the flowers, and conveys it to the pharynx.f\nMollusca.\u2014Gasteropoda. In the acephalous mollusca there is, of course, no tongue. But the Gasteropoda are provided with a very singular apparatus, which, since it is usually called the tongue, cannot be allowed to pass observation here, though its right to such an appellation is somewhat questionable. Its form is subject to much variation, but it may be described generally as a thin membrane, long and narrow, the greater extent of which is rolled into a tube. This tubular part (Jig. 759. A, b), occupies the posterior portion of the membrane, the end being closed, while its anterior extremity is open and in connection with the oesophagus ; in front of the tubular part of the tongue is a continuation of the same membrane, which is here flat, and in many\n* Ce qu\u2019on a nomm\u00e9 langue dans les col\u00e9opt\u00e8res et les orthopt\u00e8res, ou l\u2019extremit\u00e9 membraneuse de la l\u00e8vre inf\u00e9rieure, en m\u00e9rite \u00e0 peine le nom. Cuv., Le\u00e7ons d\u2019Anat. Comp., t. iii. p. 347.\nf Kirby and Spence, vol. iii. p. 453.\nspecies also, as in the common whelk (Buccinum undatum), it is recurved (fig. 759. A, 2).\nFig. 759.\nl\t\u00c2\n5 A. 1. Vertical section of bead of Limax maximus, showing the relative position of the mouth, a; tongue, b ; and oesophagus, c.\n2. Retracted proboscis of Buccinum undatum, a, mouth; b, tongue; c, oesophagus.\nB, single row of tongue-teeth of B. undatum.\nThis membrane is covered on its upper surface with transverse rows of minute teeth, or rather plates with tubercular or toothlike processes upon them. The number of rows is considerable, and very variable, the terrestrial species averaging, probably, about eighty, and the marine possessing often many more ; the number of plates in each row is subject to still greater variation : the common whelk (Buccinum undatum) has but three (fig. 759. B), the large garden slug (Limax maximus) has 180. The shape of the plates in terrestrial gasteropoda is usually irregularly quadrangular, slightly longer than broad, while in some fluviatile and marine species they assume most complicated and elegant forms (fig. 759. B). The centre plate of the row is always symmetrical, and its denticular projections point in the direction of the closed end, i. e. backwards, and nearly horizontally. The plates on either side of this central plate usually assume in terrestrial gasteropods much the same form and direction, while some of the fluviatile and most of the marine species present such an endless variety of forms, that the most that can be said of them, generally, is that the dental processes point backwards. Fig. 759. B represents a row of the dentigerous tongue-plates of the Buccinum undatum : there are seen to be only three ; the central one symmetrical, the lateral ones of very different form, individually non-symmetrical, but having an exact correspondence to one another. The tongue itself (fig. 759. A, 2) is attached, as before stated, to the oesophagus near its anterior extremity, and lies beneath it. In the Helices and Limaces it is enveloped in the muscular head of the gasteropod (fig. 759. A. 1), its posterior blind end being just visible at the back part of the head, some distance below the point where the oesophagus leaves that part and passes into the abdominal cavity. In the whelk tribe it lies beneath, and parallel to, the oesophagus, and is free, though surrounded by strong muscular bands, the general direction of which is also parallel to the tongue. It is in this tribe that the anterior end of the tongue is curved downward,","page":1142},{"file":"p1143.txt","language":"en","ocr_en":"1143\nTONGUE.\nwhile its posterior extremity unlike terrestrial species, is furnished with a strong retractile muscle. In some other marine gasteropoda, as the limpet, a very small portion only of the tongue is included in the head, whilst the rest of it lies folded up in the abdominal cavity, between the intestines and the muscular foot, but perfectly free ; and in some cases it is nearly twice as long as the entire length of the animal.\nOf the uses of this curious apparatus it is difficult to speak with certainty. The short thick tube of the terrestrial gasteropods appears adapted for the trituration of food preparatory to its passing into the oesophagus : these species are furnished with a large, strong, horny plate, fixed in the mouth at the upper part of the head, and, consequently, the flat end of the tongue acts as an under jaw working against this horny plate. It is not easy, however, to imagine that the long narrow tube of the whelk tribe can be used in the same way for triturating food, though the envelope of strong muscles would favour that idea, while the consideration of the still longer and perfectly free tube of the limpet renders this use of the tongue among the marine gasteropoda still more improbable. It is well known that the Buccinum undatum and its allies use the flattened portion of the tongue as a file, with which they bore holes through the shells of other species and then feed upon them, and the muscular apparatus by which this is effected is an admirable piece of mechanism. It consists of a protractor muscle, over the anterior extremity of which the curved portion of the tongue is flexed, which, by its self-elongation, probably by intrinsic transverse contraction, projects this recurved portion of the tongue from the mouth, and keeps it there ; when the tongue is thus protruded, the retractor muscle, already alluded to, attached to its posterior blind extremity, contracts rhythmically, and so pulls the recurved portion with a sawing motion over the extremity of the protractor muscle, which acts as a pulley for it : thus the teeth which cover the outer or free surface of this reflected portion are brought into the relation, with the objects on which they are to act, the most advantageous for filing them away. But this gives us no clue to the determination of the manner in which the tubular part of the tongue is employed, nor am I aware of any probable conjecture having been advanced upon the subject.\nProfessor Loven, of Stockholm, has proposed a system of classification of gasteropoda founded upon the forms of the tongue-plates and their arrangement ; and it is probable that conchologists will find the suggestion a valuable one, not so much for the sole foundation of an arrangement as for a check upon classification on other bases.*\n* For much of the above detail I am indebted to Mr. Thomson, of King\u2019s College, as well as for the specimens from which the drawings were made.\nCephalopoda. Hitherto, in the insects among the Articulata, and the gasteropods among the Mollusca, we have only seen in the tongue an instrument for facilitating, mediately or immediately, the prehension of food : in the Cephalopoda we have the first structural indication of the sense of taste, and apparently in a perfection consistent with the high organisation of the animal in other particulars. In both the tetrabranchiate and dibranchiate orders of cephalopods we meet with tongues of very similar structure, possessing in both an anterior and posterior soft papillose part, and an intermediate portion invested with a horny lamina, beset with rows of recurved spines. It is hardly possible to help seeing in this distribution of parts the strong analogy it presents to the mammalian tongue, in which the gustatory papill\u00e6 are situated near the tip and base, while the centre of the dorsum is occupied by a rough indusium, subserving the same double office as the spiny lamina of the cephalopod, protecting the organ and facilitating deglutition. In the Nautilus the tongue is supported by an oblong horny substance, probably analogous to the basis of the hyoid bone, free at its posterior extremity, but embraced anteriorly by two retrahent muscles which arise from the posterior margins of the lower mandible. The anterior free extremity of the tongue itself is divided into three soft, fleshy, papillar caruncles, of which the central or anterior one is the largest. Behind them the surface is invested with a thin horny plate, on which are set four longitudinal rows of recurved spines, twelve in each row, each spine being about two lines in length. Behind this the tongue is again soft and sensory, but the papill\u00e6 are coarser ; a fleshy fold projects forward from each side of the fauces, likewise covered with papill\u00e6. In the dibranchiate order the papillary structure is less perfectly developed, and the central horny lamina, instead of being in one plane, is bent at right angles into a vertical and horizontal portion, the incurved spines being set only on the vertical part. The rows of spines are seven throughout, but in the Onychoteuthis, as they descend towards the base of the plate, the outer rows merge in those next them towards the centre till there are only three rows. The method in which the cephalopods appropriate their food, by tearing off piecemeal, by means of their strong and sharp mandibles, ortions of the prey they have seized and are olding in contact with their mouth, renders the possession of the sense of taste of high importance to them, as the immediate contact of their food prevents their testing its nature by the sense of sight : at the same time, the full enjoyment of this sense is permitted by the nature of their food, its partially comminuted condition, and their protracted method of taking it.\nVertebrata.\u2014 In the Invertebrata the definition of a tongue depends, with few exceptions, on little more than locality and function \u2014 the requisitions of a tongue and the possession of an organ of any sort that fulfils those requi-\n4 d 4","page":1143},{"file":"p1144.txt","language":"en","ocr_en":"1144\tTONGUE.\nsitions, constitute its possession, or any oral process, to which no other name can be assigned, is called a tongue. But when we enter the Vertebrata we find an organ of characteristic structure, conforming to a general type, possessing many common characters, of a form whose varieties are not so great as to prevent its being the name of a particular shape, and always constituted of those three systems previously enumerated as essential to the tongue of Vertebrata. I shall first consider the comparative anatomy of the bony system of the tongue in all Vertebrata, and then briefly refer to some of the principal characters of the organ itself in the four classes into which that subkingdom is divided.\nHyoid apparatus. \u2014 The comparative anatomy of the hyoid apparatus is a subject of high interest, as it enables us, by its reflected light, to read successfully the true nature and value of the different elements of the structure as met with in man and other mammalia. It shows us, with the certainty of a demonstration, and the contrariety almost of a paradox, that the hyoid bone in man, which we are accustomed to look upon as a single bone whose dismemberment depends merely on late ossification, is, in reality, a composite structure \u2014 a contribution from two distinct systems of bones ; that while the body and lesser cornua form part of the true endoskeleton, and are congeneric with the bony framework of the trunk and limbs, the greater cornua form part of the visceral or splanchno-skeleton, and are congeneric with the maxilliform supports of the teeth of the stomach of the lobster, or the bony pieces situated in the auriculo-ventricular ring, in the hearts of ruminants, or with other similar structures ; and that, as we must look upon these in regard to the function they subserve, as respectively digestive and circulatory bones, so we must regard the greater cornua of the hyoid as respiratory.\nTo prove the truth of this proposition, it will be necessary to examine the state of the hyoid apparatus in water-breathing animals, and to connect its condition as found in these with what we find it in air-breathers, by tracing the modifications which its different parts undergo in those animals, part of whose existence is destined to the respiration of water, and part to that of air ; we shall thus gain a clear insight into their homologies, and be able to refer part to part without the chance of fallacy, inasmuch as the link of their connection is lodged not in different individuals, but in different parts of the life of one. I shall describe it,\n1st., in fish. Professor Owen has shown that the different segments of the true hyoid arch are so many elements of the inverted or haemal arch of the third cranial vertebra. The centre of this arch in fishes (fig. 760. A) is formed by four small, subcubical bones, the basi-hyals (b lli) (two only are represented in the figure, being seen in profile), from the sides of which extend upwards, backwards, and outwards, two long and stout cylindrical pieces, the cerato-hyals (c h) ; the summit of\neach of these is surmounted by a small triangular piece, the epi-hyal (ep h), and the arch thus constituted is suspended on each side, to the base of the skull, by a small, slender ossicle, the stylo-hyal (st h), which may be considered either as the entire proximal piece of the hyoid arch, or a dismemberment of that piece, according as the posterior division of the epitympanic, to which it is attached, is looked upon as the displaced proximal piece of the next arch in advance, the tym-pano-mandibular, or as itself the proximal element of the hyoid. This completes the hyoid arch : in most fishes, however, there are two more bones attached to the centre of the apparatus, one stiliform, projecting forwards, appended to the anterior surface of the median symphysis of the basi-hyals, the glosso-hyal (g h), the true lingual or tongue-bone ; the other, the uro-hyal (u h), a vertically-expanded, triangular piece, extending backwards from the posterior surface of the basi-hyals. There are generally appended to the posterior and lateral surface of the cerato-hyals and epihyals a series of slender, slightly curved rays, varying in number from three to thirty, but generally about seven, as in the cod (Gadus Morrhua) (fig. 760. A) ; their office is to support the membrane that covers in the branchial chamber, whence they are called branchio-stegals (b, b).\nImmediately behind the hyoidean arch, we meet with a system of arches, the branchial, whose office is to support the gills, and whose structure, position, development, and connections prove them to have no relation with the true skeleton : they are generally five in number ; the four anterior being branchial, the last, which is dentigerous and guards the gullet, pharyngeal. Each arch rises laterally from a median chain of ossicles attached to the basi-hyal, or uro-hyal when ossified, and consists of a short inferior piece, the hypo-branchial, surmounted by a long, curved piece, the cerato-branchial, bending first outwards and upwards, then forwards and inwards, under the base of the cranium. Now, these arches are what were just now stated to be homologous with the posterior or greater cornua of the hyoid apparatus, in all vertebrate forms, whenever they exist ; that they are so, will best be shown by tracing the modifications they undergo in the metamorphoses of the anourous batrachians. Fig. 760. B, 1. represents the hyoid and branchial apparatus in the water-breathing tadpole ; B, 2, where the same animal has become the air-breathing frog. In the full-gilled tadpole (B, 1), a simple basi-hyal (b h) supports laterally two cerato-hyals (c h), and posteriorly two short hypo-branchials (h 6), to each of which are attached four cerato-branchials (c b). The second stage is marked by the divergence and growth of the extremities of the hypo-branchials and the progressive absorption of the cerato-branchials. At the third stage, the cerato-branchials have disappeared, and the hypo-branchials have assumed the character of true greater hyoidean cornua (B, 2, h b). In the fourth stage they","page":1144},{"file":"p1145.txt","language":"en","ocr_en":"TONGUE. Fig. 760.\n1145\nComparative anatomy of the hyoid apparatus. ( After Geoffroy and Owen.)\nA, Fish (Cod). B, Keptile {Frog : 1, tadpole ; 2, adult). C, D, Bird (C, Crane ; D, Woodpecker).\nE, Mammal (Horse).\nbecame ossified, and, together with the cerato-hyal, coalesce with the basi-hyal. As in their previous condition they subserved to respiration, so now they do the same \u2014 as they before supported the branchiae, so now they support the trachea and larynx : they may be always recognized by this relation, \u2014 they always embrace the commencement of the air-passages in their fork, being especially connected with the first segment of the cartilaginous framework of those passages, namely, the thyroid cartilage ; the universality of this relation has induced Professor Owen to name them, in air-breathing vertebrata, thyro-hyals (fig. 760. C, D, E, hb, cb).\nIn birds (fig. 760. C and D), the elements of the true hyoid arch are either rudimentary or suppressed, while the hypo- and cerato-branchials (h b, c b) are enormously deve-\nloped. The basi-hyal (b h) is generally elongated proportionately to the shape of the tongue, and to its anterior extremity is usually attached a glosso-hyal (g h), to its posterior a stiliform uro-hyal (u h) which is prolonged beneath the trachea. In C, which represents the hyoid apparatus of the crane ( Grus cinerea), the glosso-hyal is seen to be wanting, and two rudimentary cerato-hyals (c h), lesser cornua, to be attached to the anterior extremity of the basi-hyal. In D is represented the hyoid apparatus of the woodpecker (Picus)-, the parts are seen to be very long and slender, furnishing the means for the lengthened protrusion of the tongue in pursuit of food. All the bones are seen to be linear ; there is a long basi-hyal (b h), surmounted by an arrow-shaped glosso-hyal (g h), while two slender hypo-branchials (h b,) (greater cornua) are","page":1145},{"file":"p1146.txt","language":"en","ocr_en":"1146\tTONGUE.\nsurmounted by two cerato-branchials (c b) of extreme length and tenuity, which, curving round the bird\u2019s occiput and vertex, are inserted by their cartilaginous extremities into a canal in the upper mandible, the orifice of which is placed to the inside of the right nostril ; the true hyoid arch is here entirely suppressed. And, indeed, birds\u2019 tongues are not attached, they are slung; now, tongues are attached by the osseous or fibrous continuity of the hyoid arch ; they are slung by the loose, unattached hypo- and cerato-branchials ; and accordingly as either of these methods of connection with the body is most consistent with the tongue\u2019s functions, so the one or the other of these systems of bones preponderates.\nIn mammalia we find the hyoid apparatus recurring in its original completeness ; the three pieces, the stylo-hyal, epi-hyal, and cerato-hyal, composing the lateral arms of the arch in the fish, have each their representative : the proportion of these parts, the completeness of their ossification, and their anchylosis, or separateness one from another, are liable to great variety, but either in the bony or ligamentous condition, fused or separate, the parts may be always traced. The cerato-hyals are represented by the lesser cornua ; the stylo-hyals have their homologue in the styloid process of the temporal ; and the epi-hyal, or intervening portion of bone, is a cylindrical ossicle connecting the two : these are seen in their greatest completeness in the true carnivora. In man the epi-hyal is not normally ossified, but remains in a permanently ligamentous condition, as the stylo-hyoid ligament. In some rare instances, this ligament has been ossified, and then the typical condition of the hyoid arch is restored ; two or three of these instances have been recorded and figured by Geoffroy. In fig. 760. E is shown the condition of the hyoid apparatus in the horse ; the stylo-hyals are seen to be very large, and approximate so nearly to the cerato-hyals, that the intervening bone, corresponding to the stylo-hyoid ligament in man, is seen to be a mere pisiform nodule (ep h) ; the hypo-branchials, or posterior cornua (h b), are of much the same shape as in man, while the basi-hyal projects forwards in a rostrum, to which is attached a glosso-hyal in two pieces (g h). In the ox the condition is much the same as in the horse, but the epi-hyals are longer, and the stylo-hyals shorter.\nI will now briefly advert to the general characters of the tongue itself, as met with in the four classes of Vertebrata,\u2014Pisces, Rep-tilia, Aves, and Mammalia.\nPisces. \u2014 The tongue in fish is very rudimentary ; in some it cannot be said to exist at all ; in others it is a thin, fleshy investment, that barely covers the glosso-hyal bone projecting into the mouth. In the herring (Clupea Harengus), it seems to be represented by a small muscle passing along the floor of the mouth to be inserted into the symphysis of the lower jaw, to depress and open which seems to be its function. In the cod it is\nround and thick, and seems to act as a sort of cushion. In the conger (Murcena Conger), in which it is very large, it seems to possess a hyo-glossus muscle, which, arising from the inferior portion of the hyoid arch, passes forward on either side of the tongue, which, by the action of one of these muscles, can thus have a lateral deflexion imparted to it. The structure of the investments of the tongue is not such as to imply the possession of taste in any degree, or any thing but a very low sensibility. In some species, as, for instance, in the sole (Solea vulgaris), the surface is regularly rugose, and might, at first sight, appear to be papillary, but no true papill\u00e6 are to be met with in any fish\u2019s tongue ; their only representatives are the calcigerous processes, or teeth, with which the tongues of some species are more or less densely set, and which assist in prehension and deglutition. Whether the vascular, erectile tissue, situated on the palate of the Cyprinoids, has any connection with the sense of taste, is doubtful \u2014 probably not.\nReptilia.\u2014The tongues of Reptilia possess a very wide diversity ; some are immovable, others the most remarkable for their protrac-tility that we find in any organism ; some are long, some so short as to have been described as wanting ; some are broad and thick, some slender ; some present the development of papillae in great perfection, some are quite smooth ; the extremes of all these characters we find in the reptiles, and their opposite conditions in those the most closely allied. For example, among the Saurians, the tongue of the crocodile is so immovable, as to have been described by Aristotle as wanting; while the chameleon presents us with the most complete protractility of the organ that the animal kingdom furnishes. I think the teleologists have not a greater strong hold than that furnished them by the tongues of reptilia. Almost the only thing in common that can be assigned to them is this, that prehension is their principal function, and that the sense of taste is very subordinate.\na. Batrachia.\u2014All the Batrachia, in their perfect state, feed on living prey*, and in many of them the arrangement of the tongue, to enable them to secure it, is remarkably curious. In the frog, which presents a good example, we see the tongue reversed, as it were, the base or attached end being in front, the apex or free extremity behind : its muscular constitution explains this arrangement. It consists essentially of two muscles, a genio-glossus and hyo-glossus, invested by the mucous membrane. The genio-glossus arises from the inferior maxillary symphysis, and, directed backwards towards the throat, spreads out, and, together with its fellow, constitutes the upper of the two muscular strata. The hyoglossi arise from the lower surface of the posterior hyoid cornua, are directed forwards\nm\n* In speaking of the frog Roesel says, \u201c Pr\u00e6dam vix venatur eamdem potius pr\u00e6stolans, nec ullum unquam devorabit insectum motu destitutum.\u201d Hist, Ranar., p. 16.","page":1146},{"file":"p1147.txt","language":"en","ocr_en":"TONGUE.\t1147\nunder the flattened cartilaginous plate of the body of the hyoid bone, over the anterior border of which they are reflected as over a pulley, where, coining in contact with the under surface of the last-mentioned muscles, they curve backwards, radiate in a fan-like manner, and form the under of the two muscular layers. This is the position in a state of rest, the hyo-glossus lying under the genioglossus, and the extremity of the tongue pointing down the throat in contact with the fauces, and forming a plug with which to close the posterior nares, and prevent the regress of air every time it is swallowed. But when the animal would seize its prey, the position of the tongue is suddenly reversed; the genioglossus contracts, and moving on its genial attachment as on a centre, the tongue is thrown forwards, the genioglossus now being below, the hyoglossus above. The apex of the tongue having come in contact with the prey to be seized, and secured it by its viscid secretion, the organ is instantly retracted and restored to its original position by the contraction of the hyoglossus. In many of the batrachians (as in the Triton) the tongue is fixed in its entire extent, and is of very various shapes, oblong, rhomboidal, heart-shaped, &c., affording generic and specific distinctions, of which zoologists have availed themselves in classification. The tongues of Batrachia are invariably soft, and, in some of them, as the frog, covered with well-developed papillae, containing all the essential elements of organs of taste and touch ; that they are the seat of an acute sense of taste is, however, highly improbable, not from any thing in their structure, but from the fact that these animals swallow their prey whole, without any subdivision, frequently alive, bolting it as soon as seized.\nb.\tOphidia.\u2014In the ophidians the tongue is very much elongated, straight, flat or cylindrical, fleshy, highly protractile, and deeply cleft at the apex into two tapering points which are in a state of constant vibration when the tongue is protruded. These points are the extremities of two muscular cylinders, which form the substance of the tongue, and by their close apposition constitute that part of it that seems to be undivided : they may be traced a long way down in front of the trachea. When the mouth is opened the tongue very frequently cannot be seen, from its being drawn within a sheath which contains it, the orifice of which is placed in front of the aperture of the glottis. From this sheath, and from the mouth, it is being constantly projected, with a sort of vibratile darting movement, and, from a deficiency in the plates at the symphysis of the jaws, it can be protruded from the mouth without the jaws being separated : the character of this movement, and the pointed slender shape of the tongue, have given rise to the vulgar belief that it is the animal\u2019s weapon of offence, a sort of dart containing the poison that it instils into the wounds it inflicts. From the nature of the food of this order, from the disposition of the parts of the mouth, and from the short so-\njourn that the food makes in it, the perception of savours is probably very slight.\nc.\tChelonia.\u2014In Chelonia the tongue is not elongable, and its muscular structure is very simple, consisting only of two pair of muscles, the genioglossus and hyoglossus. In the turtles the surface is smooth ; in most of the tortoises it is clothed with very large and well-developed papillae, long, soft, and flexible, arranged with great regularity in a close pile : the structure of these papillae, together with the masticatory apparatus possessed by these animals, would imply their possession of a true sense of taste.\nd.\tSauria.\u2014Among the saurians we find in the Crocodile a fixed tongue projecting so little from the floor of the mouth, that Aristotle, as has been stated, described it as wanting; it is covered with a coriaceous integument, and is remarkable chiefly for a valve-like process at its base, formed by a reduplication of the integument over the vertical ridge of the body of the hyoid bone, which, at the will of the animal, is capable of being applied to a similar one descending from the palate, and shutting off the mouth from the posterior nares and larynx, so that the animal can breathe when its mouth is under the water or engaged with its prey, and its nostrils only above the surface. In the Lizard we find a tongue, in shape very much like that of the Ophidians.\nIn the Chameleon we find an apparatus which, for its remarkable structure and powers, has always excited the attention and curiosity of zootomists : Perrault, Hunter, Cuvier, Vallis-nieri, Vrolick, Houston, Milne Edwards, Spittal, Duvernoy, have all given their contributions to the subject ; the connection of the mechanism with the resulting phenomena, as given by these authors, has been very diverse, and all, in the opinion of Bibron, unsatisfactory. \u201c It is easy,\u201d says this author*, \u201c to conceive and explain a part of these movements, by the structure of this tongue in the chameleons, because the hyoid bone and the muscles have been perfectly described, and because it is easy to isolate them by dissection ; yet, by the very aid of this anatomy we perceive that the movements which this mechanism should effect would not suffice for the production of such an excessive elongation, that the animal, without using any violent exertion, can lance from its mouth, by a sort of ex-puition, a fleshy pipe of a length nearly equal to that of its whole trunk, and that it can retract it again within its throat with the same swiftness, and without one\u2019s perceiving any apparent movement in the rest of its body.\u201d The difficulty that Bibron felt was that of accounting for the very great intrinsic elongation of the tongue, and it appears to me to be a difficulty that exists ; various authors account for it variously ; in my own dissections I have not met clear evidence of anything that satisfactorily explains it to me. I shall first describe the tongue itself, and then the hyoidean appa-\n* Erp\u00e9tologie G\u00e9n\u00e9rale, ou Histoire Naturelle compl\u00e8te des Reptiles, Paris, 1836, t. iii. p. 174.","page":1147},{"file":"p1148.txt","language":"en","ocr_en":"1148\nTONGUE,\nmouth, it is seen to be a whitish, fleshy, ru-ratus and muscles, and from the description of the two deduce the most probable explanation of the movements.\nWhen a portion of the integument and lower jaw on one side is removed, so as to expose the tongue when retracted within the\ngous mass, about an inch and a half long, filling the buccal cavity, so as to depress the floor of the mouth and throat, in shape something of a cone with the base in front : the posterior half, or smaller part, is seen to be thrown into deep and numerous transverse rugae (fig. 761. A, b, and C.) which extend\nFig. 761.\nTongue of the Chameleon.\nA, retracted. B, elongated. C, seen from beneath, in situ, by incision and separation of the integument.\nquite up to the hyoid bone, and give to this part the appearance of an earth-worm, a simile suggested by Belon. When the tongue is drawn out it is seen to be capable of great extension (B), the extension taking place in the posterior or rugose portion, and being effected by the obliteration of the transverse rugae, which one by one are smoothed or flattened out as the extension is continued, so that when it is stretched as far as it will go by moderate traction, the tongue, instead of being an inch and a half long, of which only half is occupied by the extensible portion, is five inches long, the extensible part occupying about six-sevenths of the entire extent, and being much attenuated (B, b), while the anterior portion retains its original size and shape (a). The tongue is thus seen to be composed of two parts, a club-shaped extremity and a highly extensible medium of connection between this extremity and the hyoid bone : these two parts I shall now describe.\nThe anterior club-shaped extremity is about three quarters of an inch long, and three lines in diameter, and in shape reminds one of the corolla of a labiate flower ; in fact it is bilabiate: it has a sort of dome above (a), terminated in front by an upper lip (c), which is opposed by a more projecting lower lip (d), and between them is situated a funnel-shaped mouth, which, when closed, as in A, forms a horizontal cleft, but is capable of being opened as shown in B, (and to an extent greater than that represented in the figure,) and closed on\nany object at the will of the animal, so as to assist in the prehension of food. These lips are furnished with a sort of orbicularis, and, no doubt, too, with muscles that shall raise the upper and depress the lower ; but I have been unable to detect any fibres going in such a direction as to produce these movements. This part, as well as the whole of the tongue, is invested with the mucous membrane of the mouth, and the upper surface of the dome and lower lip, are covered with minute papillae, invested with a fine epithelium, and disposed, in the former situation, in rows, indicated by the lines (A, a). The part which covers in the infundibular cavity, and which, after the analogous part in a labiate flower, I have called the dome, Bibron has not ill compared to a tongue reversed.\nThe second portion consists essentially of a membranous tube, threaded, as it were, by the long cartilaginous stilet, or tongue bone, of the hyoid apparatus (the glosso-hyal). This cartilaginous stilet, which has been erroneously described as bony, is about an inch and a half long, and consequently passes through the entire length of the tongue when retracted, its anterior extremity being received into the lower lip of the club-shaped portion : it threads the tongue much in the same way as a bodkin threads a bag when furnishing it with a running string, and it is by the puckering of the membranous portion upon this basis that the transverse rugae are formed. The membranous tube itself (which has been compared to a pipe, a piece of intestine, a","page":1148},{"file":"p1149.txt","language":"en","ocr_en":"TONGUE.\nworm, &c.) is very complex in its structure : it consists, first, of an investment of mucous membrane, very thin and extensible, covered, apparently, by a single layer of epithelium, and a good deal of bluish-grey pigment, and underlaid by fibrous tissue disposed at right angles, transversely and longitudinally. When the sheath, thus composed, is cut open, it is seen to contain another fibrous sheath, smooth, dense, white, and shining, the proper sheath of the stilet, which it closely invests, and which smoothly glides in it. Between these two sheaths is a cavity which is occupied, first, by a longitudinal muscle on each side (essentially a hyoglossus), a very fine and slender fascicle, which runs the entire length of the tongue, and retracts it when protruded ; secondly, by a nerve on each side, disposed, when the tongue is retracted, in regular sinuosities, and, when drawn out, about five inches long ; it does not appear to give off any branches to the muscle, and does not diminish in size as it advances, so that it is probably distributed to the extremity, and is sensitive ; thirdly, by some cellular tissue loosely connecting the mucous investment with the fibrous sheath of the stilet ; fourthly, no doubt, arteries and veins. The proper sheath of the stilet does not contain a canal, but is attached to the surface of the stilet, which glides in it not by its movement on the sheath, but by the movement of the parts of the sheath on itself. When the stilet is retracted it is seen to be cylindrical throughout, but as it advances its sheath accumulates on its anterior extremity, and it seems gradually to become club-shaped, so that when the tongue is completely retracted the under lip is filled not only with the extremity of the stilet, but with the sheath accumulated on it. Cuvier has described an annular muscle existing throughout the entire length of the membranous portion, which he describes as the proper muscle of the tongue, and to which he attributes its self-elongation. If such a muscle exists, which I will not positively deny, it would fulfil all the required conditions, and leave nothing to be explained ; but I confess that, after careful microscopical research, I have been unable to find any muscular fibres having a transverse or circular disposition, all being referable to the longitudinal bundles already referred to. Hunter has described what he considered to be two coils of some firm substance, wound in opposite directions, which by their approximation would become straightened, and so lengthen the tongue ; \u2014 this is an ingenious hypothesis, but no more : there is nothing that will bear such an interpretation. Perrault, in speaking of the lungs of chameleons *, expresses an opinion that the tongue is driven, or, as it were, coughed out by the sudden expulsion of the air which the lungs contain.\nThe hyoid apparatus consists of the horizontal projecting portion \u2014 the stilet already referred to, and four cornua, two short anterior ones, and two long vertical posterior ones (fig. 761. A and B). These parts can move\n1149\nfreely on each other, the articulation between the stilet and the greater cornua is particularly free. These cornua ascend, and are suspended loosely behind the jaws ; they are about three quarters of an inch long, and are clothed with the muscles that are attached to them. These muscles are, 1st, the geniohyoid (e. A B and C.), arising from the inner surface of the symphysis menti in contact with its fellow, and inserted into the inferior extremity of the vertical cornua, sending up a slip which is attached to its whole anterior border. 2dly, a distinct, small fasciculus, the cerato-maxillary (/), arising from the inner surface of the lower jaw, and inserted into the apex of the vertical cornua. 3dly, the sternohyoid (g), arising from the inner surface of the sternal extremity of the fourth and fifth rib, and inserted into the junction of the cornua and glossal portion of the hyoid. 4thly, the cerato-sternal (Ji), more slender and flattened than the last, the antagonist of the cerato-maxillary, arising from the outer surface of the sternal extremity of the second rib, and inserted, just opposite the cerato-maxillary, into the apex of the greater cornua. 5thly, the omo-hyoid (i), inserted with the sterno-hyoid. This complicated arrangement of muscles, which I have drawn from nature* in fig. 761. A, is the mechanism for the direction and extrinsic propulsion of the tongue ; by it the lower extremities of the greater cornua are drawn forward, and the summits depressed, so that, instead of being vertical, they are horizontal and advanced (B). The advance of the whole tongue thus gained is nearly an inch, and since the muscles that principally effect it, the genio-hyoid (e), are very strong, and the movement quick and forcible, the question may arise\u2014Is this projectile movement sufficient to send the rest of the tongue forward, and effect its elongation, after the hyoid apparatus has come to a stop, in the same manner as the arrow flies from the string of a bow, though the string itself is suddenly arrested ? I think not. I think that some such muscular arrangement as that described by Cuvier must exist ; and possibly, some transverse bundles of fibres of not very characteristic appearance, which, from the absence of transverse striae, I rejected as muscle, might have been of a muscular nature. The retraction of the tongue is easily accounted for ; it is simply drawn back on the stilet by the longitudinal muscles. The use of the stilet appears to be, partly as a support to the tongue when in a state of rest, and partly to direct its movements ; for aim is seen to be taken while the tongue is still retracted : the animal first places itself in such a position that its head shall be turned directly to the object to be seized ; it then fixes its head still more accurately, then slowly opens its mouth to a sufficient distance to allow the free egress of the tongue ; it then seems to fix it with a sort of tremulous rigid\n* It may be well to state that not only these, hut all the figures illustrating this article (with one or two exceptions, which I have acknowledged), are original, and have been drawn by myself from nature, so that I can vouch for their correctness.\n* Essais de Physique, t. iii","page":1149},{"file":"p1150.txt","language":"en","ocr_en":"1150\nTONGUE.\nmovement, and, in an instant, the tongue has been shot out, has again disappeared, and with it its prey has disappeared too, the whole being performed with a velocity that startles one afresh every time it is witnessed.\nAves.\u2014The tongue of birds may be stated, in general, to be, like that of reptiles, prehensile and non-gustatory. Taste and mastication, or, at any rate, taste and some delay of the food in the mouth, always go together ; in birds the food experiences no delay in the mouth, but, in almost all cases, is bolted at once. In most instances, true prehension, or the seizing of the food, is performed by the bill, in some few by the tongue ; in nearly all, however, the securing of it when in the mouth is effected by the tongue, which is armed near the base with numerous spines, directed backwards (fig. 763. ABD), that prevent the regress of the prey, whether alive or dead, and which, with a similar structure at the roof of mouth and throat, must greatly assist the first stage of deglutition. The structure of the tongue of birds is generally such as not to admit of intrinsic elongation ; its protrusion therefore can only be effected by the movement of the organ en masse ; and this is produced to a surprising extent by a particular arrangement of the hyoid bone and its muscles, which I will now describe. The general character of the hyoid bone of birds, as already stated, is elongation\u2014longitudinal extension, and to this add the fact of the suppression, entire or partial, of osseous or ligamentous attachment of the hyoid elements to the skull, such attachment being inconsistent with the required free movements of the organ. From the posterior part of the body of the hyoid bone project back the slender posterior cornua forming, by their divergence, an acute angle, embracing in its apex the upper part of the larynx : as they pass beneath the occiput they curve upwards, and are surmounted by slender pieces, frequently cartilaginous (ceralo-branchial), having a still greater curvature; so that the whole greater cornua, as thus constituted, embrace the back of the skull, to the shape of which their curve is moulded, and on which they are made to glide backwards and forwards by the muscles that regulate the protrusion and retraction of the tongue. The principal of these muscles are two pair ; the first the analogue of the stylo hyoid, which retracts the tongue, and the second pair which Cuvier has called the analogue of the genio hyoid \u2014 the conical muscle of Vicq d\u2019Azyr, \u2014 which draws the tongue forwards : the obliquity and length of these muscles, and the free unattached suspension of the hyoid apparatus, render the movements of the tongue very free, and their range extensive. The retrahent muscle, the stylo-hyoid (fig. 762. a.), arises from the posterior part of the lower jaw, and passes forward to be inserted into the upper surface of the junction of the cornua and body of the hyoid : in some birds it is more voluminous than in the species figured, and has a more extended insertion ; it retracts the tongue. The pro-trusor ( b.), which Cuvier has named, with\napparently insufficient reason, the analogue of the genio hyoid, arises from the inner\nFig. 762.\nMuscles of the Tongue of the Fieldfare (Turdus pilaris). a, retractor; b, protrusor; c, cerato-glossal.\nside of the lower mandible, passes downwards and a little backwards to the posterior cornua, which it embraces in its fibres from the point where it comes in contact with it to its extremity : the fibres become increasingly oblique as they pass back, and embrace the cornua in a muscular cone, which, by its contraction, causes the cornua to slide forwards in it, and so protrude the tongue . in the woodpecker, in which the hyoid cornua pass completely round the head and into the upper mandible, this muscle is of proportionate length. Besides these, there is a mylo hyoid, a thin layer passing from the lower mandible to a median fibrous line, and a cerato-hyoid passing from the posterior cornua to the uro-hyal, approximating these, and so directing the apex of the tongue to the opposite side. Fig. 762. c. is a small muscle, which I cannot find described ; it passes from the under surface of the basi- or glosso-hyal to the greater cornua, into which it is inserted within the sheath of the conical muscle. I would suggest the name of cerato glossal for it ; its action is to increase the curvature of the cornua, and thereby draw the tongue back.\nFig. 763. represents some different forms of","page":1150},{"file":"p1151.txt","language":"en","ocr_en":"TONGUE.\nthe tongue in birds. A, is that of, the snipe (Scollopax gallinago'), which is seen to be linear ; B, of the fieldfare (Turdus pilaris), the epithelium breaking up into a leash of filaments at its extremity ; C, that of the king-fisher ( Al-cedo ispida), so short that it hardly projects from the surface at the bottom of its long bill ; D, is the tongue of the common goose, furnished with a linear series of spines on each side, forming a serrate margin, which, with a corresponding serration in the upper mandible, constitutes a sort of sieve, through which the bird sifts and strains, as it were, the mud and water which it palpates in search of food. In the back part of the tongue, both in this and in the other figures, there is seen to be a peculiar armature of recurved spines, whose arrangement in the different species is constant and characteristic. Some good representations of different varieties of tongues are given in the article Aves.\nMammalia.\u2014The tongue of mammals differs not in any material point from that of man. The proportion of the different parts of its muscular structure differ more or less widely from the human type, and we find certain muscles that have no place in the tongue of man: to enter into the minutiae of these diversities would not, however, comport with the scope of the present article ; they must be sought in monographs especially devoted to this part of the subject. The coincidence of the size and form of the tongue with that of the inferior maxillary arch is very general ; in the rodents this is very conspicuous, the tongue being of the same wedge shape as their cuneiform jaw. In some animals, as in the ant-eater and giraffe, the tongue admits of great elongation, and becomes an important organ of prehension. The different elements of the tegumentary system are merely modifications of those found in man : the three orders of papillae are generally sufficiently conspicuous, and in most instances they are more regularly arranged, and their structure is more typical than in the human subject ; for instance, the circumvallate papillae are symmetrical, they present a greater contrast to the rest in number, being fewer than in man, and none of the fungiform approach them in form 5 the shape of the fungiform too is not liable to any variety, and they are implanted with great regularity among the conical. The conical papillae are generally true cones, and are arranged with mathematical precision in lines in different directions, accordingly as they are viewed. All these papillae may be well seen in the dog. In the felid\u00e6 the conical papillae of the centre of the dorsum are converted into recurved spines of great size and strength, which the animal uses in scraping the meat from the bones when feeding, and in combing its fur.\nFunctions of the Tongue.\u2014 The physiology of the tongue, like its organisation, is double, all its functions being referable either to those sensory or muscular endowments which it possesses in so remarkable a degree. Naturally, these are intimately associated, its sensibility being necessary for\n1151\nthe direction of its muscular action, and its movements necessary for the perfection of its sensibility; a systematic consideration of them, however, necessitates their separation, and those functions that are referable to the tongue as an organ of sensibility, have already been treated of in the articles Taste and Touch, to which the reader is referred ; it only remains for me to consider those that it possesses as an organ of motion.\nThese are prehension, mastication, insalivation, deglutition, speech, and one or two unimportant and non-essential offices in which it is engaged, which may be called the accidents of its physiology, as despuition or spitting, whistling, &c. Of these the four first-mentioned belong to the tongue as an organ of digestion ; they are, in fact, the first four stages of that process; all four exist in all mammalia, the first and the last in all vertebrata ; speech and the other non-digestive motor functions are peculiar to man.\nPrehension. \u2014 The tongue is not, properly speaking, in man, an organ for the prehension of solid food, that office being performed by the hand, for which the opponent arrangement of thumb and fingers eminently fits it, so that the human tongue has not those additional qualifications which we find in other animals to adapt it for an organ of prehension. And this, I may remark, is an instance of a very general law\u2014that the ascent in the animal scale is not a passage from anima s with simple organs to animals with complex organs, but from simple individuals with organs of complex function, to complex individuals with organs of simple function, the addition as we ascend being, not of functions, but of parts to discharge those functions, and the advantage gained, not another thing done, but the same thing done better. Thus in man, instead of having one office more, the tongue has one office less than in many animals below him ; and the delicate and extended prehension supplied by his hands, diminishes by one item the complexity of function, and, therefore, of organisation of his tongue. So that in judging of the elevation of animals by their individual organs, supposing such a method to be admissible, we must not look to complexity of structure of those organs, but to the perfection of the resulting function. But to return.\nIn the prehension of liquids, or suction, the tongue in man is engaged; constituting a movable wall of the oral cavity, it acts as a piston, and draws the liquid into the mouth by the formation of a temporary vacuum. Bichat enumerates three methods of the prehension of liquids, by suction, by drinking from a vessel, and by infusion into the throat; in the first two the tongue is concerned ; in the last, which seems to me hardly to deserve the name of prehension, it is not. In suction, which is peculiar to the infant, the nipple is seized by the lips, which are compressed around it by the orbicularis oris ; the velum palati is elevated so as to close the posterior nares ; the tongue forms, by the contraction","page":1151},{"file":"p1152.txt","language":"en","ocr_en":"TONGUE.\n1152\nof the middle fibres of the genio-glossus, which depress its centre, a longitudinal channel, which receives the nipple, and transmits the milk to the pharynx as long as a vacuum continues to be formed. In drinking liquids from a vessel the tongue forms a channel for its transmission, but it flows down to the pharynx by its own proper gravity.\nMastication.\u2014As far as relates to the tongue, which here, however, is only subsidiary to the teeth, the mechanism of mastication may be divided into three stages:\u2014first, that of placing the food in an advantageous position with regard to the teeth; secondly, affecting the position of the food in a definite manner when under the action of the teeth ; thirdly, collecting the scattered portions of masticated aliment prior to deglutition. Immediately on the introduction of a morsel of food into the mouth, either bitten by the incisors or otherwise, it is at once transferred to the molars, so that it shall project beyond them, outwards, against the cheek ; the cheek is then pushed against it by the action of the buccinator, and the food is slowly driven across the teeth, which are rhythmically opened and closed, the tongue at the same time pushing moderately against it on the inside and so regulating the movement imparted to it by the cheek. Thus we see that the food under mastication is subjected to an equable and regulated motion ; that it is placed, as it were, between two movable walls, and that by the even lateral movements of these walls, and the rhythmical vertical action of the teeth, its perfect mastication is secured. As soon as the cheek has pushed it inwards as far as it can, an interval in the rhythmical closure of the teeth takes place, and the tongue restores it to its former position, again to be pushed inwards, and so on. The equable mastication of the food is secured much in the same way as the even motion of a rod of timber, under the blade of a circular saw, secures the cutting off of pieces of equal thickness. Any one who watches himself whilst eating will at once observe the sets of rhythmical action, interrupted by short interval, in which the food is restored to its necessary position between the teeth. The third stage, that of collecting the food from all parts of the mouth, admits of no particular description.\nInsalivation.\u2014There is no separate or super-added process for insalivation; it proceeds contemporaneously with mastication, the motions which are necessary for the one supplying equally the required conditions of the other ; while the food is being comminuted by the teeth, dispersed by their action to different parts of the mouth, recollected by the tongue to be again dispersed, and so on, the salivary secretion is freely mixed with it, and reduces it to a homogeneous pulp : thus mastication facilitates insalivation by breaking up the food, and insalivation facilitates mastication by softening it. As one set of acts performs the two processes, of course there are not any additional movements of the tongue to describe.\nDeglutition.\u2014When the food has attained a sufficient moisture and softness, which is appreciated by the tongue\u2019s sense of touch, it is collected into a mass, and the process of deglutition commences. Physiologists have divided this process, and the division is a good one, into three stages, which may be distinguished respectively as the oral, the pharyngeal, and the oesophageal: the first conducts it past the anterior pillars of the fauces, the second includes its transmission from that point through the pharynx into the oesophagus, and the third commences with its arrival at the oesophagus, and terminates with its entrance into the stomach. The first is entirely voluntary ; the second is of a mixed nature, engaging partly voluntary and partly involuntary muscles, and, though practicable at will, is yet impressible on the transference to the back part of the tongue of the material to be swallowed ; the third is wholly involuntary. With the two first alone the tongue is engaged, and, therefore, of these alone I shall speak.\nThe first stage is merely the reference of the ball of alimentary matter to a point on the back of the tongue, posterior to the anterior pillars of the fauces. This is effected by the pressure of the tongue against the palate, whereby the food is forced back between the two.\nThe second stage is a much more complex process, involving a more varied mechanism, and engaging in it different parts, the tongue, the pillars of the fauces, the soft palate, the larynx, and all the muscles of the pharynx. As soon as the food has passed the anterior palatine arch, that arch contracts, and by its constriction entirely prevents the regression of the food into the mouth ; at the same time the base of the tongue, and with it the food, is carried further back, and a second closure takes place from the approximation of the posterior pillars of the fauces, produced by the contraction of the palato-pharyngeal muscles that form them: this part of the mechanism requires a little explanation. The contraction of the anterior pillars of the fauces closes the entrance into the mouth by a constriction or sphincter-like action : this is due to the general circular form of the constrictor isthmi fau-cium occasioned by the inward curvature of the upper and lower extremities of each palatoglossus muscle. The contraction of the palato-pharyngei is not of this nature ; they have not the same inward curvature above and below, and their inferior attachments to the posterior borders of the thyroid cartilage are capable of very little approximation; when, therefore, they contract, the soft palate being fixed, they approach one another laterally like two curtains, leaving a narrow chink in the middle, wider below than above. As soon as the food has passed this point, this contraction takes place, so that the two muscles of the opposite sides almost touch, the chink between them being occupied by the relaxed uvula ; the passage into the posterior nares and upper part of the pharynx is thus cut off, which has induced Dzondi to call the posterior palatine","page":1152},{"file":"p1153.txt","language":"en","ocr_en":"TONGUE.\t1153\narch the velum palati posterius. At the same time that this is taking place, the base of the tongue is thrown back upon the epiglottis*,the larynx being drawn upwards and forwards to meet it, so that the rima glottidis is completely closed, and the food glides safely down, over the inclined plane thus formed, into the pharynx raised and dilated to receive it : the food then comes within the grip of the constrictors of the pharynx, which successively pass it downwards to the oesophagus. This process takes place so rapidly that it is difficult to trace its parts in succession, and indeed some of them, which apparently succeed one another, are in reality contemporaneous : thus, the first stage\u2014the raising of the dorsum of the tongue to the palate\u2014is that which mainly contributes to the inclined plane of the second stage ; and the raising and carrying forwards of the larynx under the tongue is that which principally dilates the pharynx.f\nThe third stage, or the oesophageal, conducts the food to the stomach ; it is of that peristaltic or vermicular nature that characterises all the succeeding movements of the alimentary canal ; the muscles concerned are entirely involuntary, and the nature of the act purely reflex. The tongue is not concerned in it.\nSpeech. \u2014 The tongue is the instrument principally engaged in those modifications of the oral passages which give rise to articulate sounds, which, definitely grouped and combined by man, and taken as the representatives of certain objects, actions, qualities, and relations, constitute Language. The consideration of this interesting subject, however, will more appropriately fall under the article Voice, to which the reader is referred.\nMorbid Anatomy of the Tongue. \u2014 The tongue is obnoxious to a variety of morbid changes, which might naturally be expected from the number and nature of the elementary tissues which enter into its formation, as well as from the diversity of the functions it has to perform, and the exposure to injury in which it is placed; \u2014 changes which may consist either in some increase, decrease, or disproportion of its normal elements, in some lesion or morbid change in those elements, or else in the superaddition of some adventitious growth.\nThe tongue may be affected with inflammation, hypertrophy, atrophy, induration ; with ulceration, numerous morbid changes in the conditions of the papillae ; with tumours, cancer, aphthae ; and the organ, moreover, is subject to be displaced, \u2014 there is prolapsus of the tongue, the tongue may be inverted\n* It would seem that the epiglottis is not absolutely necessary for the protection of the rima glot-tidis, but that the pressure of the base of the tongue over it is sufficient ; as there are authentic cases on record, in which the epiglottis was quite destroyed by syphilis, and yet deglutition was never attended with any inconvenience.\nt For a detailed account of this process, see Dzondi, die Functionen des weichen Gaumens. Halle,. 1831.\nVOL. IV.\nand embraced by the pharynx \u2014 swallowed; and the tongue may be unnaturally fixed by an unusual extent of frenum, the individual thus circumstanced being tongue-tied.\nInflammation of the tongue. \u2014 The morbid changes caused by inflammation of the tongue are modified by the structure of the organ. There is one form of this disease in which, from the extreme vascularity of the tongue and the distensibility of its covering, it swells to an enormous size with great rapidity, and subsequently recedes without suppuration : this I have ventured to call erectile. In other cases the tongue suppurates. The constitutional action of mercury is another cause of glossitis. I therefore divide glossitis, for its more complete consideration, into \u2014 I. Idiopathic (1. Suppurative ; 2. Erectile) ; and II. Mercurial.\nSuppurative glossitis. \u2014 This is an extremely uncommon affection. It commences with heat, swelling, induration, and some fever; matter presents itself at various lengths of time, forming a more or less circumscribed abscess. It generally occurs on one side, and points just beneath the edge of the tongue. According to Dr. M\u00f6ller, of Zealand, scrofulous persons are most liable to this affection. Instances are recorded by Mr. A. Smee, Dr. Graves, Dr. M\u00f6ller, and one example occurred in the practice of the author\u2019s father. This latter patient was a lady, recovering from an attack of influenza. Her tongue, which was affected principally on one side, became swollen, tender, hard, stiff, and incapable of movement. She could not speak, and swallowed with great difficulty. At length the pus was evacuated, and the tongue healed, and recovered all its functions immediately. This lady now possesses a remarkably good use of the organ.\nErectile glossitis. \u2014 This malady, though less rare than the preceding, is still quite uncommon. The morbid condition of the tongue in this disease appears to consist in an enormous and rapid distension of the organ by blood, rendering it very large, hard, and stiff. In the majority of cases it occurs in people in perfect health, and seems to be a purely idiopathic inflammation : in some cases it seems to have followed exposure to cold, and in others it was associated with febrile disorders. In this disease the first change which occurs is a perceptible enlargement of the tongue, which feels rather stiff, painful, and tender with a little difficulty in speaking, the patient being in other respects well. The case generally proceeds rapidly ; in two or three hours the tongue is much larger; there is a good deal of distressing burning felt in it. Sy-nocha, symptomatic of the local inflammation, now occurs, and goes on increasing with the glossitis, and the patient becomes anxious and alarmed. The tongue occupies now the whole cavity of the mouth, or even protrudes, and the jaws are kept apart. Mr. Martin thus describes the condition of the tongue at this stage ; \u2014 \u201c On examining the tongue, I found that it occupied a large proportion of the\n4 E","page":1153},{"file":"p1154.txt","language":"en","ocr_en":"1154\tTONGUE.\ncavity of the mouth ; and I could with difficulty introduce my little finger between it and the upper jaw. It felt smooth and hard to the touch, and had a thick coating of viscid mucus : from the high degree of tension, the point presented a glistening appearance.\u2019\u2019\n(Edinburgh Med. and Surg. Journal, vol. xxviii. p. 76.) As the case advances the tongue increases still further in size, the patient cannot perform the first part of the act of deglutition, and the liquid food is obliged to be conveyed by some mechanism into the pharynx ; respiration through the mouth ceases, and that through the nares is impeded : the patient is now almost on the verge of suffocation, and his distress and anxiety become extreme. Mr. Martin remarks: \u2014 \u201cAt this period respiration through the mouth was totally suspended ; and he could not breathe, even through the nostrils, but with difficulty. His countenance was flushed and anxious, the pulse was fluttering, his breathing offensive : in short, he was threatened with immediate suffocation.\u201d (Loc. cit., p. 77.) The condition of the tongue sometimes approaches gangrene. Mr. Hayes, in describing a similar case at an advanced stage, observes : \u2014 \u201cIt now began to look of a dark black colour, or rather as if it had been broiled over a smoky fire; indeed, I expected it would mortify.\u201d (Memoirs of the Medical Society of London, vol. ii. p. 193.)\nI am not aware that mortification has ever resulted in these cases ; neither does abscess appear to be thus produced,* which, however, may be accounted for by the fact, that these urgent cases almost always render it necessary that the organ should be freely incised on the dorsum to evacuate the distending blood, and this would prevent the formation of abscess ; though in some very severe instances, where incision has not been practised, no abscess has resulted. When the inflammatory action ceases, which is immediate when the before-mentioned operation is performed, the tongue rapidly recovers, and the fever vanishes. When the tongue is incised, the quantity of blood discharged is very great.\nThe morbid change in the tongue does not always go to the extent above described, and then milder symptoms are produced. Dr. England mentions two mild cases, in both of which the left half of the tongue alone was affected. Dr. Graves relates a severe case, also confined to the left side, in which he says the part \u201c appeared on the verge of gangrene.\u201d (Dublin Hospital Reports, vol. iv. p. 43.) De Lamalle narrates an example, in which the patient was almost suffocated in five hours from the first appearance of the malady. The tongue was more than three times its natural size ; it filled the whole mouth, and protruded between the teeth. Free incisions saved the organ and the patient. Trincavellius mentions a case where it oc-\n* Since the above has been in type, a case occurring to Dr. Schneider has been published, -where this form of inflammation terminated in abscess. (Casper's Wochenschrift. No. 23.)\ncurred in Variola ; Mr. Hayes an instance, where an individual, licking an urticarious eruption, had this effect produced to a slight extent on her tongue ; and the same thing, to a small degree, I have known occur from a person eating mussels.\nCollier, Taynton, Job \u00e0 Mekren, Paletta, Elbuig, Frank, and Orgill, also enumerate examples of this condition.\nDr. Craigie has described a peculiar form of glossitis, under the name of Lingual Quinsy, which is an extension of ordinary quinsy, or tonsillitis. The portion of the tongue involved is that bounded in front by the circumvallate papillae, behind by the epiglottis, and at the sides by the mucous membrane passing off upon the pharynx and rami of the lower jaw. The inflammation extends down the palato-glossus muscle from the tonsils to the base of the tongue, and seems to involve the mucous, submucous, and muscuiar tissues. The parts are swollen, infiltrated, and stiff ; the lower jaw cannot be depressed, and attempts at deglutition are not only difficult, but the completion of the act is impossible. There is an abundant secretion of ropy mucus. Dr. Craigie had one fatal case, in which he found fter death, that \u201c the base of the tongue was cumid, hard, and much distended with blood and serum infiltrated into its cellular tissue, and the parts between that and the angle of the jaw were in like manner infiltrated.\u201d (Edin. Med. and Surg. Journal, vol. xlii. p. 26.)\nMercurial glossitis. \u2014 Inflammation of the tongue, the result of the mercurial action, is but one symptom of the constitutional influence of that drug. The tongue in this case becomes large, soft, painful, white and furred, and much indented by the teeth along its edges : the epithelium is soft and readily removed, and the surface is apt to ulcerate. The swelling is sometimes very great and rapid. Siegel and Trincavellius each mention such a case. I believe it has never-caused suppuration of the organ ; but the discontinuance of the mercury is followed by complete resolution.\nUlceration of the tongue.\u2014This is the most frequent of the morbid changes occurring in the tongue, and of it there are several species and varieties. The different species may be enumerated as, I. The Dyspeptic ulceration, or that arising from disorder of the primae vi\u00e6 ; II. Indurated non-malignant ulceration ; III. Gangrenous ulceration ; and IV. Syphilitic ulceration.\nDyspeptic ulceration is met with in three principal forms. 1. Small circular ulcerations at the tip and along the edge of the tongue ; 2. Severe and deeper ulcerations of the body of the tongue ; and, 3. Aphthous ulceration.\nThe small circular ulcers of the tongue are extremely common, and have been personally experienced by almost every individual. They consist of small, circular, generally regular and well defined ulcers, which are superficial and look as if a piece of mucous membrane had been punched out ; the edges are sharp and","page":1154},{"file":"p1155.txt","language":"en","ocr_en":"TONGUE.\nwell defined : these ulcers vary in size from that of a pin\u2019s head to that of a split-pea, or larger ; they are almost constantly situated at the tip, or edges of the tongue ; they are sometimes grey, at others red ; when touched against the teeth they are acutely painful, and their presence causes an abundant and constant secretion of saliva. In the commencement, however, there is no ulceration, but the malady begins by an affection of a papilla, consisting in an effusion of lymph into a fungiform papilla (hereafter to be described), and this terminates in ulceration : the papilla is at first large, yellow, and distended with lymph ; in a few hours it has disappeared, and its site is occupied by an ulcer, which afterwards more or less spreads in a regular, centrifugal manner. I believe this process has never before been properly described, \u2014 persons not being aware that any thing has happened until the ulcer exists, and consequently never seeing or exhibiting the malady in the first stage ; but any one, subject to these little infirmities, may satisfy himself of the truth of what I have said by carefully watching the state of his tongue from day to day.\nThe severe and deep-seated ulcerations of the tongue, arising from mere disorder of the alimentary canal, may consist of an extension of the already-described variety, or it may commence by a vesication, or an excoriation of the surface ; it generally occurs in people who are debilitated from some cause or another. Mr. Lawrence relates the following characteristic case : \u2014 \u201cA lady, between fifty and sixty, of unhealthy appearance, with a red pimply face, who had often suffered from disorder of the digestive organs, consulted me for a disease of the tongue of formidable appearance. The middle and upper part of the organ was swollen, and occupied by a deep ulcer of irregular figure and foul aspect. It was very painful, interfering with mastication and articulation. The digestive organs were much disturbed. The complaint yielded speedily and effectually to simple measures \u2014 regulation of diet, and the digestive organs, small doses of extract of henbane, and soothing local means.\u201d (Clinical Lecture, Medical Gazette, vol. xxxvi. p. 800.)\nMr. Lawrence mentions an instance in which rawness and severe excoriation of the tongue often repeated, the result of periodic and long-continued dyspepsia, appear to have induced true seirrhus of the organ.\nAphthous ulceration. \u2014 The ulceration is merely one stage of a peculiar morbid change, to which the tongue, in common with some other portions of the gastro-intestinal mucous membrane, is liable. The tongue, however, suffers more severely than most other parts. It is eminently the result of disordered digestion, and is accompanied with more or less fever of an atonic character. An aphthous tongue is rather swollen, tender, and furred, and has a sensation of burning heat : on its surface, scattered about irregularly, are small white bodies, resembling little masses of curd, varying in size from a split pea to a pin\u2019s-\n1155\nhead, attached pretty firmly ; these bodies, as well as the swollen state of the tongue, cause the subject of them pain and inconvenience : after a variable time these little white masses fall off, leaving the membrane on which they rested in an altered condition,\u2014it is either raw and excoriated at these spots, the epithelium being peeled off and leaving the papillae naked, exposed, and red ; or else, the deeper elements of the membrane being affected, an ulcer is formed. These ulcers are generally more or less circular and superficial, and are in no way to be distinguished, at this stage, from the little circular ulcers already described, but aphthae on the neighbouring portions of the tongue disclose their true nature. The white aphthous mass itself has been variously described as a slough, concrete mucus, and alhu-mino-fibrin, but it consists in reality of a minute parasitic fungus, which attaches itself to the mucous membrane and burrows among its epithelial cells. Seen under the microscope, it is found to be composed of threads matted together like felt, and intertwining among the epithelium. Accompanying aphthae are generally to be seen on the surface of the tongue, small vesicae, spots of epithelium raised with a little serum underneath, and also some of the papillae distended with fibrinous exudation \u2014 conditions to be described presently.\nIndurated non-malignant ulceration.\u2014Indurated ulcers, which are neither syphilitic nor malignant, but closely resembling seirrhus, are occasionally met with, and their doubtful character gives the surgeon not a little trouble. Mr. Lane narrates the following formidable example : \u2014 \u201c Mr. G. B., aged 33, came to me in the month of June, 1813, with a very foul ulcer beneath the tongue, and said that he some time before had had one on the upper part of it, which he said was healed ; but on examination there was a deep irregular fissure, with raised, jagged, hardened edges, communicating with the ulcer under the tongue, which, on examining with a probe, I found not only communicated with the fissure on the upper surface, but the instrument passed through the substance of the tongue, into a deep seated ulcer at the root of it, and thence into the throat. The general appearance of the disease was most alarming, bearing a very strong character of carcinoma. He experienced great pain and difficulty in deglutition, and complained that the pain had of late extended behind the ears, to the back of the head and neck.\u201d (Medico-Chirur. Trans., vol.viii.p. 202.) The case, however, was not one of carcinoma, for the patient completely recovered under alterative treatment. About two years since an instance came under my own notice. A man of about 45, had been a sailor ; had never had syphilis ; for about six years had been labouring under a disease of the tongue, with little improvement, or permanent change, in its condition. When I saw him, the right half of the tongue was enlarged and much indurated ; the left was of natural size and soft, but with few papillae ; on the right side no papillae were to be seen, and the surface was ex-4 e 2","page":1155},{"file":"p1156.txt","language":"en","ocr_en":"TONGUE.\n1156\ncoriated, chapped, and in parts superficially ulcerated. He told me that at one time the left side had been diseased in a similar way. The lymphatic glands behind and beneath the jaw and down the neck were enlarged and indurated, and had been so from the first. The free application of lunar caustic to the tongue lessened the affection, and the lymphatic glands became smaller and softer ; but the other side became afterwards diseased, and was relieved by the same treatment ; the tongue was, however, never restored to a healthy state, though, when I last saw him, there was no ulceration. There was profuse secretion of saliva ; but, with this exception, the man was remarkably healthy.\nMr. Lawrence, in his Clinical Lecture, already referred to, describes this condition of tongue. (Loc. cit., p. 799, case ii.)\nGangrenous ulceration.\u2014The tongue is liable to a peculiar gangrenous ulceration, called \u201c Glossanthrax \u201d or \u201c Malignant pustule.\u201d It commences as a vesicle containing bloody serum ; it gradually becomes black and bursts, and the lingual tissues beneath and around it are seen to be gangrenous ; this may proceed till the whole tongue is in a state of mortification : when it exists to this degree, there is fever of a profound typhoid character, with delirium, and the patient soon dies. Audral has given an account of this disease in his Pathological Anatomy. Heyfelder narrates the case of a Prussian butcher, who, when slaughtering a diseased sheep, put the knife and held it for some time between his teeth. In two or three days the margin of his tongue was covered with black pustules. The part swelled alarmingly, and most painfully ; violent fever set in, and the patient was carried off in the course of sixty hours.\nI once saw a patient in low fever, who had enormous sloughing of the dorsum of the tongue, which proceeded in successive portions till a large deep excavation, that would have received half a walnut, was produced.\nSyphilitic ulceration.\u2014Hunter* strangely fell into the error of thinking that venereal ulcerations of the tongue are uncommon, whereas they are the most common to which the organ is liable ; and the tongue, next to the tonsils, is more frequently attacked, in the constitutional forms of this disease, than any other portion of the mucous surface.\nA small, circular, superficial ulcer is the most common syphilitic affection of the tongue ; it begins exactly like the little ulcers of dyspeptics, from which it cannot be distinguished. These ulcers are situated principally at the tip and along the edges of the tongue. As in almost all instances of ulceration of the tongue, the ulcer is the second part of the process, and follows the deposition of fibrinous matter under the basement membrane ; in this case in a single papilla, or a few contiguous ones, as I have already described. These ul-\n* Speaking of ulceration of the tongue, Hunter observes, \u201c these are commonly supposed to be venereal ; but I believe they seldom are.\u201d (.Hunter's Treatise on the Venereal Disease. Page 337. 2nd Ed. 4to.)\ncers generally do not extend, but yield to the most simple treatment ; sometimes, however, they do extend, and form various sized unhealthy ulcers, deep in proportion to their extent, cupped and indurated at the base. At other times they show a tendency to run in one direction, and remain superficial : I saw an example of this in a patient who had a very narrow superficial ulcer an inch in length, originating in a small circular ulcer, and extending along the under surface of the tongue, on the left side, just at the point where the mucous membrane is reflected from that organ to the jaw : it was very superficial, and, as it progressed, it attacked the healthy membrane in its course.\nRhagades or fissures in the tongue are not uncommon : they are ulcerated clefts, which extend down, often to a considerable depth, into the substance of the tongue. Mr. Lawrence describes one three quarters of an inch deep ; though sometimes they only form a chap in the mucous membrane : he also describes one extending the whole length of the tongue, just in its centre, in the long axis ; this was deep, and with irregular ulcerated edges. When seen in the fore part of the organ, they are generally in the middle line, or nearly so ; but those further back are scattered about, and just in front of the cireumvallate papillae, which is their most usual situation. They are commonly associated with an indurated and irregularly tuberculated surface of tongue \u2014 these tubercular lumps being sometimes like large fissured warts, at others glossy and smooth. The rhagades are generally red, while the surrounding tubercles are grey, or whitish, or, at other times, red and excoriated.\nThe glossy tubercle, to which I have referred, is a remarkable disease : it often forms with great rapidity, and as quickly disappears. It seems to consist in an effusion of lymph into the cellular tissue underlying the mucous membrane ; this effusion is very dense, and raises and distends the surface of the t\u00f6ngue at the affected part above the surrounding portions ; the effect is, that the complications of the membrane, which constitute the papillae, become unfolded, and the papillae are, as it were, opened out, \u2014 they form now one smooth extent, and stretch over a large surface, the faintest indications only of the papillae being apparent, and sometimes they are totally obliterated. That this is the true explanation of these smooth tubercles is evident from the fact, that as they form, and in proportion to the distension of the membrane, the papillae diminish and shorten ; and as, under the influence of medicines, the swelling decreases, they reappear exactly in the same ratio. These tubercles have little sensation or pain, unless the surface be excoriated ; they are dense, almost as hard as schirrus ; their base is felt pretty deep in the substance ot the tongue ; their surface is polished, glossy, and whitish\u2014 they remind me of the tongue of a fish ; they are generally oval or round, when smallish and single, and they are most frequently situated on the dorsum of the tongue, about half an","page":1156},{"file":"p1157.txt","language":"en","ocr_en":"TONGUE.\t1157\ninch or an inch in front of the circumvallate papillae, and on one side of the mesial line. Sometimes they form over the whole surface of the tongue. I am acquainted with a gentleman who, at the time he was suffering from syphilitic psoriasis, got an attack of dyspepsia ; in less than thirty-six hours the whole of his tongue was one mass of these tubercles, and not a papilla was to be seen ; in a few days (under the influence of iodide of potassium) every papilla had reappeared, and the tongue was in every way natural. This influence of disordered stomach being the immediate and exciting cause of the manifestation of the syphilitic poison on the tongue, I have frequently noticed ; a person who has a taint of lues venerea can scarcely sustain the least disorder of the stomach or bowels without its showing itself upon the tongue. These tubercles of the tongue, when left to themselves, are very apt to become fissured and form rhagades ; the space between two of them is liable to be the seat of an ulcerated fissure. Deep circular ulcers sometimes form on these tubercles.\nPhaged\u0153nic syphilitic ulcers are seen occasionally on the tongues of feeble debilitated people.\nAll these forms occur as the result of the constitutional taint of lues venerea, at various periods after the primary symptoms. I have known the glossy tubercle and rhagades occur fifteen years after the primary sore.\nCancer of the tongue. \u2014 The tongue is liable to be affected with scirrhus, having all the properties of genuine cancer. Mr. Travers has given a very graphic description of cancer of the tongue, which I shall take the liberty of quoting in extenso. \u2014 \u201c This is not a smooth and firm rounded tubercle, such as is often met with in this organ, but an irregular rugged knob in its first stage, generally situated in the anterior third, and midway between the raph\u00e9 and one edge. It sometimes, but seldom, extends across the middle line, although it often extends alongside of it. The hardness is unyielding, inelastic, and the mucous surface puckered and rigid. It also gives to the finger and thumb of the surgeon the sensation of solidity, or of its penetrating the entire muscular substance, being perceived equally on either surface. Sharp shoots of pain are felt through the side of the affected organ, towards the angle of the jaw and ear. The disease tends to run backwards towards the base or posterior edge. It sometimes acquires great bulk before ulceration takes place, so as to project the tongue from the mouth. In this state a female patient of mine was seen some time ago in St. Thomas\u2019s Hospital, in whom the permanent projection of the diseased organ, beyond the widely distended lips, was from three to four inches. The ulceration often extends from the edge of the tongue to the membrane of the mouth and gums, when the elevated and distended membrane at length gives way, and ulceration is rapid. The surface of the ulcer is very uneven ; clean and\nbright granulations appearing in parts, and in others deep and sloughy hollows. The darting pain is very acute, but only occasional. There is a dull aching always present, and as constant a spitting as in deep salivation. It happens to strong and hitherto healthy persons, for the most part males from the age of forty onwards. There is generally an evening paroxysm of pain, and the nights are much disturbed by the secretion accumulating in the throat, which excites cough. Often the patient is roused by a painful compression of the tongue falling between the jaws. Speech is much affected and painful.\n\u201c Towards the fatal termination of the disease, occasional profuse haemorrhages take place at shortening intervals, and alarm and weaken the patient, who ultimately dies tabid and exhausted, generally with symptoms of more extensive disease of the mucous membrane in other parts.\n\u201c The period at which the sublingual and contiguous lymphatic glands become affected, and the extent of their change, are very variable. I have known them form the base of the tumor, the cauliflower fungus occupying half the tongue, i. e. two or three inches long and one broad ; after death the jaw was found covered with fungus.\u201d (Medico-Chirurgical Transactions, vol. xv. part i. p. 245.)\nThe scirrhus is not infrequently at the very margin of the tongue. Louis mentions a case where 'here was a little circumscribed tubercle of scirrhus, about the size of a filbert, at the edge of the tongue : it was ulcerated.\nIt occasionally shows itself early in life : Arnott mentions a case where it was present in a girl of fifteen.\nIn a subject who died of lingual cancer, dissected by myself, I found that the whole of the right side of the tongue, right tonsil, the upper part of the pharynx on the right side, and the mucous membrane, extending from the tongue to the epiglottis on the same side, were removed by ulceration, and the inner surface of the lower maxilla laid bare. The other half of the tongue was healthy, and only the ulcerated edge was scirrhous. The lymphatics were enlarged, and of a greenish-yellow colour : they con-ained pus.\nTumours of the tongue. \u2014 A variety of tumours have been met with in the tongue.\nFatty tumours have been found by Mr. Liston on the under surface of the tongue. Mr. Hale Thomson exhibited to the Westminster Medical Society, in 1839, a fatty tumour which he removed from the side of the tongue. It consisted of fat contained in a cyst.\nEncysted tumours. \u2014 Many of the so-called instances of ranula* have been abundantly proved by Dupuytren, Breschet, and Malgaine to be simply serous cysts, and not obstructed salivary ducts. They consist of dense membranous cysts, containing a thick albuminous\n* The consideration of ranula belongs to the morbid anatomy of the salivary glands, and not of the tongue.\n4 E 3","page":1157},{"file":"p1158.txt","language":"en","ocr_en":"1158\nTONGUE.\nfluid, and not inspissated saliva. They are situated in the cellular tissue immediately under the mucous membrane, where they sometimes grow to an enormous size. Mr. Earle has described curious little vesicular tumours, which he found in the tongue of a boy : \u2014 \u201c Clusters of very minute semitransparent vesicles pervaded the whole thickness of the tongue, occupying nearly one-half, and projected considerably both above and below that organ. The slightest injury caused these to bleed profusely, and in some places the clusters were separated by deep clefts, which discharged a fetid, irritating sanies.\u201d (Medico-Chirur. Trans,, vol. xii. pt. ii.) The tongue was quite restored by the use of internal medicine.\nA mulberry-Uke tumour has been described by Mr. Probart. It formed on the tip of the tongue of a boy four years of age. It was of a peculiar granulated appearance, resembling a half-ripe mulberry, feeling hard and free from pain. It grew gradually : at two months it was the size of a nutmeg ; but after that, in five weeks, it rapidly increased till it was of the bigness of a hen\u2019s egg, protruding nearly two inches beyond the lips, which were separated widely by it, preventing the little patient taking any thing but spoon meat, and that with difficulty. It was highly vascular, and bled profusely from innumerable vessels, which nothing but the cautery would arrest, when amputated. There was no return of the disease,\nPolypus-like tumours have been met with on the tongue, consisting of a fleshy mass, like the rest of the organ, attached to it by a pedicle. Louis mentions one of these about the size of a nutmeg, which he removed from the tongue of a young man eighteen years of age; it was situated on the middle of the dorsum of the tongue. A more remarkable example is described by Dr. Huie. The case was yhat of an old maiden lady, in whom a tumour formed, about three months after a catarrh and inflammation of the fauces, upon the root of the tongue, and gradually increased for twelve months, when \u201c the smooth rounded form of the tumour conveyed, at first sight, the idea that it was of an encysted kind ; but, upon examination with the finger, it was found to be as hard and unyielding as the substance of the tongue itself, and evidently of the nature of polypus.\u201d (Edinb. Med.-Chirur. Trans., vol. iii. p. 72.) It filled nearly the whole pharynx, and moved with the tongue, to which it was attached by a pedicle. Ligature was subsequently applied, by which it was removed. \u201c The tumour, which is in the Museum of the Koyal College of Surgeons (of Edinburgh), was of an oval form, weighed exactly an ounce, and measured five inches in its long, and four in its short, circumference. It was broadest opposite the insertion of the pedicle, which entered at the distance of an inch from the upper part of the tumour. A longitudinal incision, which has been made into it, displays a firm cartilaginous nucleus, as large as a\nchestnut, surrounded by a fibro-cartilaginous structure, forming the rest of the tumour.\u201d (Loc. cit., p. 76.) I strongly suspect that all these pedunculated tumours of the tongue are hypertrophied fungiform or circumvallate papillae.\nHypertrophy and prolapsus of the tongue.\u2014 This is a singular affection, which usually commences in infancy, and is sometimes congenital. It generally begins and progresses slowly by an enlargement of the organ within the mouth ; it afterwards projects permanently between the lips, and then advances more rapidly, and the tongue, which was before of normal, though hypertrophied, structure, becomes parched and fissured on the upper surface, and ulcerated beneath. Sometimes the amount of tongue that is protruded is enormous. The os hyoides and larynx are drawn up, whilst the jaw is depressed, and the incisors are pushed out in a horizontal direction.\nDr. Wells, of Columbia, has given a good case, of which the following is a condensed description. The patient was a little girl, six years old, with an enormous enlargement of the tongue ; otherwise she was in good health, and a fine robust girl. The following are the dimensions and state of the tongue at the time : \u2014 length, as it remained at rest and hung down over the chin, from the superior incisors to the apex, two and a half inches ; circumference just in front of the lips, six inches ; breadth, from one angle of the mouth to the other, a little more than two inches. It had undergone a very considerable change in structure, was much more dense than natural, and not subject to change in its dimensions by the action of its own muscles, or, if at all, very slightly so. Its motions otherwise were sufficiently free : upper surface smooth ; inferior covered with the cicatrices of old ulcers, several of which, where the tongue rested upon the alveolar processes of the lower jaw, were but imperfectly healed ; colour darker than natural. Within the mouth the tongue had undergone no apparent change except a moderate increase in width and thickness. The front teeth had been displaced from the lower jaw by the long-continued pressure of the tongue. The lower lip was folded downwards. The anterior portion of the superior maxillaiy bone had undergone a slight curve upwards ; the inferior a much greater curve downwards; so that when the back teeth came in contact, the front were an inch asunder, or, rather, the space between the upper teeth and the corresponding alveolar processes below was something more than an inch. This condition of tongue commenced by an attack of glossitis in infancy. A portion of the organ was removed by ligature, and she completely recovered.\nMr. Crosse mentions a girl of six years old, in whom the tongue was prolapsed three or four inches ; and this was completely reduced by pressure and leeching.\nMr. Liston has described an instance in which the tongue projected three or four","page":1158},{"file":"p1159.txt","language":"en","ocr_en":"1159\nTONGUE.\ninches from the lips of a young man, nineteen years of age, the disease having been congenital. It was of a brown and livid colour, rough, granulated, and fissured, and beneath the mucous membrane were abundant venous plexuses. This tongue was liable to periodic intumescence, when it became much larger, was very painful, and bled profusely. Mr. Liston has stated his belief, that, from the periodical enlargement and diminution of the tongue, and the erectile tissue being evident in many parts of its surface, the mass was partly composed of a structure resembling aneurism by anastomosis.\nThese hypertrophied tongues, when curtailed by the knife or ligature sufficiently to be taken within the teeth, generally soon accommodate themselves to the form and dimensions of the oral cavity.\nProfessor Lassus has given instances, where this has been accomplished by means of bandaging and compressing the tongue.\nAtrophy of the tongue. \u2014 I am not acquainted with any instance of atrophy of the entire organ, nor with any unassociated with paralysis. It generally shows itself in cases of hemiplegia, when the tongue does not immediately recover, and results from diminished nutrition, the consequence of want of exercise, being confined to the paralysed half, just as the arm and leg of the affected side become atrophied under the like circumstances. It is more obvious, however, when the hypoglossal nerve alone is the seat of injury or disease. Professor Budd mentions, in his lectures, an instance which fell under the care of his brother, Dr. William Budd, of a man who sustained a stab in the neck, dividing the external carotid artery and hypoglossal nerve on the lef 2ide. The artery was secured, and the man recovered with palsy of the left side of the tongue. At the end of some weeks that half of the tongue was much wasted, and all the movements of the organ were performed by the other half. The atrophy was confined to the muscular element of the organ : taste and touch remained uninjured.\u2014 ( MS. Notes of Lecture.)\nDupuytren mentions an example of atrophy and paralysis* of the left half of the tongue caused by the pressure, upon the hypoglossal nerve, of an hydatid cyst in the anterior condyloid foramen.\nIn this condition, as well as in hemiplegia, the state of the tongue is remarkable from one part of the organ being passive, while the other is active. As long as it is at rest, the diminished size of the affected side is all that is observable. When the tongue is extruded, it is thrust over towards the affected side,\u2014it emerges from the mouth obliquely, because the extruding muscles of the sound side have no antagonists. The paralysis of the intrinsic transverse muscular fibres gives rise to another phenomenon, which I have never seen de-\n* In both these cases the muscular motion was the only function implicated, which, as Dupuytren observes, is interesting physiologically ; taste and ordinary sensation not being in the least affected.\nscribed,'\u2014it is the curved form of the tongue itself ; the raphe in the middle of the tongue is not straight, but curved, and the concavity looks towards the affected side. These fibres, whose function it is to make narrow, and, by that, to lengthen the tongue, only act on one side, and only half the tongue is thus elongated ; and this, being adherent to the other half which sustains no elongation, is thrown into an arch, on the same principle as the curving of the compound wire in a Br\u00e9guet\u2019s thermometer.\nDiseases ofthepapillce.\u2014 In considering the diseases of the surface of the tongue, authors have not taken sufficient care to consider the true anatomy of the papillary membrane, and their descriptions are consequently loose and ill-defined. It is of the utmost importance to state where the morbid changes are situated ; whether above or beneath the basement membrane ; whether it is the epithelium, or the vessels and sub-basement areolar tissue that have undergone the alteration.\nThe papillae are liable to hypertrophy, atrophy, effusion of blood or of fibrine into their interior ; they may be denuded of their epithelium, or that covering may be stained or rendered opaque, producing what is called fur.\nHypertrophy ofpapill\u00e6. \u2014 The circumvallate papillae are liable to be enlarged, the central portion forming a little tumour, rising above the surrounding ring of membrane. Dr. Andrew Ferguson has described them as increasing to the size of peas. There are generally several affected at once. I have seen them increased to this size, as well as some of the fungiform papillae at the back of the tongue, in an individual suffering from scrofulous enlargement of the tonsils. The polypoid tumours (retaining the same form and proportions as these papillae, though greatly enlarged), I believe to be nothing more than hypertrophied fungiform, or circumvallate papillae.\nThe conical or filiform papillae are liable to a peculiar change, which has, to the best of my knowledge, never been described. It consists in an enormous increase in their epithelial element, forming long cylindrical rods ; in fact, hairs : the only apparent change in these organs being superficial to the basement membrane. I am in possession of the notes of two examples of this malady. For the first I am indebted to my brother, Dr. James Salter. He observes, \u201c My patient was an old gentleman, impoverished by intemperance ; his general health was good, and he was now temperate : for some years he had suffered from the peculiar affection of the tongue under which he now laboured. This affection was a great elongation of the conical and filiform papillae, in all parts of the tongue where these abound : they were eight or ten times their natural length, and over-lapped each other, like the pile of plush, or long velvet. The hypertrophy appeared to be entirely in the long axis ; there was no increase in circumference, and they were little larger at their base than the apex. They were soft, and lay over lapping each other on the sur-4 e 4","page":1159},{"file":"p1160.txt","language":"en","ocr_en":"1160\tTONGUE.\nface ; and by smoothing the finger over the tongue they could be brushed from one side to the other. Their colour was deep Vandyke-brown, and they were most numerous in the centre of the tongue. They looked exactly like little brown hairs. Sensation and taste were both a good deal damaged.\u201d To my friend, Dr. Joseph Bullar, I am indebted for the other instance. His patient was an old lady of sixty-five ; she had been subject to constipation, for which she was in the habit of taking strong purgatives. The tongue was large, vascular, and the papillae of all kinds prominently marked. It looked in an irritable condition, as if sympathising with a congested mucous membrane. On the middle and back of the dorsum was a patch of hypertrophied filiform papillae, of a dark sepia colour, or rather of the brown colour of a dark typhoid tongue. These filamentous growths were removed by forceps, and some were sent to me, from which I made the accompanying drawings. The specimens that I received were very dark, almost black : I have some of them in my possession now, nearly or quite half an inch long ; their texture was very compact, and their shape cylindrical, with hardly any trace of tapering. They all, as seen by the\nFig. 764.\nA portion of hypertrophied filiform papilla, showing its length and true hair character. Mag. 25 and 80 diameters.\nmicroscope, possessed a retrorse imbrication of the same character as ordinary filiform papillae (fig. 764.). The epithelium did not contain any granular pigment, but the colour appeared \"to pervade the whole cell, which was evenly stained and semi-transparent. In fig. 764. is seen a papilla, or hair, at full length, and in fig. 765. a portion of another, showing the imbrication of the epithelium.\nThe Scarlatina tongue contrasts remarkably with the preceding ; for here the deeper elements of the papillae are principally the seat of change. In scarlet fever the capillaries of the papillae, in common with the sub-basement vascular system of so large a portion both of the internal and external surfaces of the body, become turgid, and the papillae themselves \u2014 not so much their epithelium\u2014become en-\nFig 765.\nA portion of hypertrophied papilla, showing well the retrorse imbrication of its epithelium. Mag. 200 diameters.\nlarged and red. In the early stages of the fever this change is concealed by the fur (which is a sodden and opaque condition of epithelium), as it regards the filiform papill\u00e6, \u2014fur being, in all cases I believe, confined to these and the papillae conicae. Not so the fungiform papillae ; for these are exaggerated and bright red. The result is, that the surface is a combination of thick white cream-like fur and red projected spots, the former being most conspicuous where the filiform papillae abound \u2014 the central portions of the tongue, \u2014 and the latter in the regions of the papillae fungiformae \u2014 the edges and tip of the tongue. These fungiform papillae look like theachaenia scattered on the surface of the fruit of the strawberry. As the disease advances, the epithelial covering is shed, and only a thin transparent epithelium remains : the papillae are consequently red and bright all over the surface, which is clean, rough, red, and rawlooking in every part.\nAtrophy of the papill\u00e6 is occasionally met with. Mr. Lawrence mentions the case of a person in whom, from habitual drinking, the tongue was, for the greater part of its surface,","page":1160},{"file":"p1161.txt","language":"en","ocr_en":"] J61\nTONGUE.\ndestitute of papillae : it was white, smooth and opaque on the surface. I have already mentioned the obliteration of the papillae in the glossy tubercle of syphilis, and it also occasionally occurs in lues venerea, independent of the tubercle.\nI have seen the tongues of old people remarkably bald, especially as it regards the filiform papillae : as a general rule, these papillae are less prominent in the aged.\nEffusions into papill\u00e6.\u2014 The fungiform papillae are liable to be the seat of little extravasations of blood. I am acquainted with a medical gentleman who has himself frequently had this trivial affection. It has always occurred to him in the night, and is indicated by a sharp pain, as though the tongue were stabbed by a red-hot needle, caused, doubtless, by the pressure of the blood upon the nerves in the papilla. Upon examining the tongue a papilla is seen to be distended into a minute capsule of blood, at first red, and afterwards black. The coagu-lum is absorbed in a few days, and the papilla resumes its former appearance.\nLymph of a grey or ash-colour is apt to be deposited in and under the papill\u00e6, in the tongues of persons tainted with syphilis. When this occurs on the dorsum, it gives a grey speckled appearance to the patch, some of the papill\u00e6 in the spot being unaffected. It looks as though this circumscribed surface had been rubbed with chalk. The patches vary in size from a split pea to a fourpenny piece. Occurring under the tip and along the under edge of the tongue, the appearance is a whitish even spot, of gristly texture, and not presenting a speckled appearance, the papill\u00e6 here being invisible, and covered up uniformly with epithelium. This is the most common situation for these spots, which after a time become fissured, and ulcerate.\nLymph, effused into a fungiform papilla, is the commencement of the common little circular ulcer on the tip and edge of the tongue. I have snipped off, and examined under the microscope, one of these papill\u00e6. It was filled with a yellow, opaque, granular, sub-fibrous mass; The papilla is not only enlarged by this effusion of lymph, but is altered in form ; its pedicle is elongated, and its head flattened. When the papilla does not ulcerate,but returns to a healthy state, its contents are absorbed, it diminishes in size, and the summit of the papilla becomes pitted in the centre. It then gradually assumes its natural size, shape, and colour. This may be easily seen by watching, every few hours, a patient\u2019s tongue through an ordinary pocket lens.\nDenuded papill\u00e6. \u2014 The papill\u00e6 are occasionally denuded by the effusion of serum between the basement membrane and epithelium, by which this latter is raised into a blister, and is subsequently rubbed off by the motions of the tongue, leaving the red naked papill\u00e6 beneath. This denuded surface is red as compared with the surrounding, and smooth, but when viewed through a magnifier the small naked papill\u00e6 are seen to be regular and perfect. This surface is not ulcerated, but feels\nsore when touched. I have lately seen a patch, the size of a shilling, thus denuded in a patient suffering from diarrhoea.\nFur. \u2014 Thefur of the tongue is the epithelium, principally of the conical and filiform papill\u00e6, variously altered. It is most abundant where these papill\u00e6 are most plentiful, and it will be found, by inspecting minutely a furred tongue, that the fungiform papill\u00e6 have undergone very little, if any, change. I believe, with M. Piorry, that the fur of the tongue is chiefly dependent upon the condition of the saliva and mucus of the mouth : and, holding this view, it is easy to understand how it is that the filiform and conical papill\u00e6 are principally affected ; they hang among the fluids of the mouth, exposing a large superficies in proportion to their bulk ; their surface is uneven and broken, and this, with the imbricated state of the epithelial particles, make them quickly and thoroughly imbibe, and become saturated with, any fluid into which they are immersed. In all this they contrast with the fungiform papill\u00e6, whose surface, in proportion to bulk, is small, and whose epithelium is spread in a thin, even sheet, smoothly over their surface. It must have been observed by every one, that the colour of the papill\u00e6 of a brown typhoid tongue is identical with that of the sordes around the teeth, which is nothing more than the saliva and mucus, in which these papill\u00e6 have been bathed, inspissated, and is doubtless the source of their colour. The white fur consists of a white, opaque, soft, sodden epithelium, which, when viewed under the microscope, differs from the epithelium in its ordinary state, in no other particular than its opacity. When the fur is brown, the epithelium presents the appearance of being simply and evenly stained. There are no opaque pigmentary particles in the cavity of the cell.\nThe various amounts and characters of the fur ; the different arrangements of it in different diseases and at different stages ; the alterations, form, and size of the tongue, &c. ; all symptomatic of morbid changes elsewhere, and belonging rather to the physician than the morbid anatomist, I shall not stop to describe. But it must not be forgotten that, in health, many of these conditions are natural to some persons: in some, the tongue is habitually furred, in others it is chapped, ragged, and irregular.\nThe healing and reparation of the papillary surface of the tongue is not a little remarkable. I have known the surface of the tongue, after it has been immensely disfigured, especially in syphilitic cases, by tubercles, and rhagades, and ulcers, restored almost to its former condition. After ulceration it would seem that the cicatrix contracts to a mere line, while the surrounding mucous membrane becomes extended, and either fresh papill\u00e6 form, or else the minute simple papill\u00e6 increase in dimensions, and become complicated, for the papillary surface is ultimately quite restored.\nI shall conclude these observations on the","page":1161},{"file":"p1162.txt","language":"en","ocr_en":"H62\tTONGUE.\nmorbid anatomy of the tongue with some remarks on faulty positions which the organ occasionally obtains. 1 have already spoken of prolapsus of the tongue, and there now remain for consideration \u2014 tongue-tie, tongue-swallowing, and adhesion of the tongue to adjacent parts.\nTongue-tie. \u2014 This is a congenital malformation, consisting in the fraenum extending too far forwards and being short, thus tying down the tongue behind the incisor teeth of the lower jaw. This may occur to any degree, from an amount that is scarcely observable, to the complete tying down the tip of the tongue behind the necks of the middle incisors of the lower jaw. The fr\u00e6num generally consists simply of a small amount of fibrous tissue contained in the fold of mucous membrane; but it sometimes contains fibres of the gemo-glossus, which occasionally extend a considerable way forwards : in the former case the fr\u00e6num is thin, in the latter it may be of some thickness. When left to nature the tie gradually lengthens, and, at the same time, recedes, and any unusual thickness arising from the presence of muscular fibres gradually lessens. This condition, to a slight extent, is very frequent, and appears to be hereditary. The cases are, however, extremely rare where the fr\u00e6num is so short as to interfere with sucking, mastication, deglutition, or articulation.\nTongue-swallowing. \u2014 This arises from the opposite of the last condition : the movements of the tongue are too free ; it can be inverted, and its apex thrown back into the pharynx, which embraces it, and thus closes the aperture leading to the lungs, and symptoms of suffocation are the result. It most frequently happens to infants. It is enumerated by writers on Medical Jurisprudence, as one of the modes of suicide among negroes. Dr. Gordon Smith, Majendie, and Beck refer to cases of it. Mr. Crosse tells of an instance, where it could be performed at pleasure without the slightest inconvenience.\nAdhesions of the tongue. \u2014 Bernard relates an instance, in which adhesions, of the thickness of two lines and a half, had agglutinated the lateral parts of the tongue to the internal surface of the cheeks, to the extent of more than an inch on each side. These adhesions had succeeded an inflammation in the inside of the mouth and tongue, the circumference of which had ulcerated ; they interrupted the functions of speech and mastication. M. Bernard divided them by a single clip of the scissors.\nNecrosis of the hyoid hone. \u2014 The only instance of disease of the hyoid bone with which I am acquainted, is one related by Mr. Spry. The disease was necrosis, the result of extended ulceration, which commenced in the throat, and continued till the bone was laid bare and dead. It was then expectorated entire. The patient died several weeks afterwards. The bone was entirely deprived of periosteum, irregular on its surface, and in a perfect state of necrosis.\n[Since this Article has been in the press I have become acquainted with a discovery of Prof. K\u00f6lliker\u2019s, that the muscular fibres in certain situations are bifurcated and branched. In a letter to Prof. Bowman he says, that this is brilliantly exhibited by the muscles of the tongue, and he gives a pen and ink illustration of the method of branching. There can be no doubt about a fact so detailed by such an authority, but I must confess that I have not recognised the appearances described.]\nBibliography. \u2014 Albinus, De Periglottide et Corpore reticulari Lingu\u00e6 ; in Annot. Acad. t. i. Alcock, Med. Gazette, Nov. 1836. Andral, Anat. Pathol, sect. ii. Arnott, Med. Gazette, vol. xxiii. Beck, Medical Jurisprudence, 1842. Bellini, Gus-t\u00fbs Organon novissime detectum. Bologna, 1665. Bibron, Erp\u00e9tologie Generale, ou Histoire Naturelle compl\u00e8te des Keptiles. Paris, 1844. Bichat, Traite d\u2019Anatomie Descrip. t. ii. Paris, 1802. Blandin, M\u00e9m. sur la Structure de la Langue, Archives G\u00e9n. de M\u00e9d. t. i. Paris, 1823. Breidenstein, De Morbis Lingu\u00e6. Erlangen, 1791. Breschet, R\u00e9pertoire d\u2019Anatomie ; Journ. Univers, des Sciences M\u00e9dicales, 1817. Collier, Med. Gazette, vol. xii. Craigie, Edin. Med. and Sur. Journ. vol. xlii. Crosse, Trans. Prov. Med. and Sur. Assoc. 1887. Cruveilhier, Anat. Descrip. Cuvier, Le\u00e7ons d\u2019Anat. Comp. t. iii. 1805. De Lamalle, M\u00e9m. de l\u2019Acad. de Chir. t. v. Dupuytren, Chirur. Clinique, t. iii. Dzondi, Die Functionen des weichen Gaumens. Halle, 1831. Earle, Med. Chir. Transact, vol. xii. England, Provincial Med. and Surg. Journal, 1846. Ferguson (A.), Med. and Phys. Journal, 1802. Frascati, De Lingu\u00e2. Bologna, 1665. Gerdy, M\u00e9m. sur la Struct, de la Langue ; Archiv. G\u00e9n. de M\u00e9d. t. vii. Paris, 1825. Idem. Discus, et Propos d\u2019Anat. Paris, 1825. Art. \u201c Glossite,\u201d Diet, de M\u00e9d. Graves, Med. Gazette, 1841-2. Dublin Hosp. Rep. vol. iv. Haller, lib. ix. and xiii. Hayes, Mem. of Med. Soc. of Lond. vol. ii. Heister, De Lingu\u00e2 san\u00e2 et \u00e6grot\u00e2. Altdorf. 1716. Heyfelder, Med. Vereins-Zeitung, 1834. Hildebrandt, Handbuch der Anatomie des Menschen. Brunswick, 1832. Home (Sir E.), On the Structure of the Tongue and removal of Parts by Ligature, in Phil. Trans. 1805. Pract. Obs. on Cancer, 1805. Horn, Ueber den Geschmacksinn des Menschen. Heidelberg, 1825. Huie, Edin. Med. Chir. Trans, vol. iii. Hunter, On Venereal. Lond. 1788. Isenflamm, De Motu Lingu\u00e6. Erlangen, 1792. Kempelen, Mechanismus der Menschlichen Sprache. Wien, 1791. Kirby and Spence, Introduction to Entomology, vol. iii. ^ Louis, M\u00e9m. Physiol, et Path, sur la Langue ; M\u00e9m. de l\u2019Acad. de Chir. t. v. Malpighi, De Lingua. Bologna., 1665. Marjolin, Manuel d\u2019Anatomie, t. ii. Paris, 1815. Meckel (J. F.), Manuel d\u2019Anatomie G\u00e9n\u00e9rale, t. iii. Paris, 1825. M\u00fcller, Physiology, by 'Rally. Owen, Lectures on Comparative Anatomy, vol. i. and ii. Archetype and Homologies of the Vertebrate Skeleton. Dissection of the Pearly Nautilus, 4to. 1832. Paletta, Journal of Foreign Medicine, No. xix. Panizza, in Edinb. Med. and Surg. Journ. Jan. 1836, and Med. Gazette, Sep. 1835. Ridge, Glossology. Lond. 1844. Rinder, De Lingu\u00e6 ln-volucris. Strasb. 1778. Rowland, Aglossostomo-graphie, ou Description d\u2019une Bouche sans Langue, &c. Saumur, 1630. Royen, De Fabric\u00e2 et Usu Lingu\u00e6. Leyden, 1742. S\u0153mmerring, leones Orgau-orum Humanorum Gust\u00fbs et Vocis. Frankf. 1808. Todd and Bowman, Physiological Anatomy, vol. i. Treviranus, Biologie, t. iv. Van Laer, De Struct. Capillorum Humanorum. 1841. Waller, Philosophical Transact. 1849, part 1. Walter (A. F.), De Lingua Iluman\u00e2. Leipsig, 1724. Wells, American Journ. of Med. Science, 1833. Willis, in Trans, of Phil. Soc. of Cambridge, vol. iii.\n(//. Hyde Salter.)","page":1162},{"file":"p1163.txt","language":"en","ocr_en":"TOUCH.\t1163\nTOUCH. \u2014 The sense through which we take cognisance of the palpable properties of bodies. The term is used, however, in two meanings, between which it is requisite to maintain a due discrimination. In its extended acceptation, it implies our consciousness of all those sensory impressions, which are neither olfactive, visual, auditory, nor gustative ; and it is therefore designated as the general sense, in contradistinction to those, which are considered as special senses. In its most limited application, on the other hand, it is used to designate that modification of the general sensibility, which is restricted to the tegumentary surface, or to some special portion of it, and which serves to excite definite ideas in our minds respecting the form, size, number, configuration, weight, temperature, hardness, softness, &c., of objects brought within its cognisance. The use of the sense of Touch, in the acquirement of these ideas, is, as we shall see hereafter, a very complex process ; involving not merely the discriminating employment of the proper organs of touch, but also the assistance of muscular action, and of the information derived from it by the \u201c muscular sense.\u201d\nGeneral Sensibility. \u2014 The most universal of all the qualities or properties of matter (that, in fact, upon which our notion of it is founded) is resistance; and it is of this quality that we find the power of cognisance most extensively diffused through the body, and most universally possessed by all beings endowed with consciousness. It would seem to require nothing else than the presence of nerves connected (directly or indirectly) with sensorial centres ; for there does not appear to be a need of any special organisation, surrounding the peripheral extremities of these nerves, in order that they may receive and transmit impressions. Thus any unusual pressure on a nerve in its course is at once perceived by the mind, \u2014 not, however, as pressure, but as a disagreeable or painful sensation, which gives no indication of the mode in which it was excited. The nerves of smell, sight, and hearing, are not thus affected by mechanical irritation, no manifestations of pain being exhibited when they are pinched, torn, lacerated, &c. ; and the general sensibility which these organs of sense possess is dependent upon other nerves. The nerves of taste, however, exhibit the same susceptibility to tactile impressions, as do those of touch ; and hence we have an additional proof of the very close affinity of these two senses (See Taste).\nThe only condition requisite for the exercise of \u201c general sensibility,\u201d beyond the integrity of the nervous apparatus, is the adequate supply of oxygenated blood. Wherever sensory nerves exist, we find them accompanied by blood-vessels ; and no non-vascular tissue possesses in itself the least degree of sensibility. Thus, in the epidermis, hair, nails, cartilage, and tooth-substance, neither nerves nor blood-vessels exist, and we find these tissues completely insensible. In\ntendons, ligaments, fibrous membranes, and in other parts whose function is purely mechanical, we find very little vascularity, and extremely little sensitiveness to ordinary impressions ; it is remarkable, however, that although the tissues, whose function it is to resist tension, are scarcely impressible by cutting, burning, &c., they cannot be unduly stretched without considerable pain. So, also, the serous and synovial membranes are not in the least susceptible of ordinary tactile impressions in their healthy state ; but they become acutely sensitive when inflamed. It does not at all follow, however, that the sensibility of a part should increase with its vascularity ; for we find that some of the most vascular organs in the body are the least sensitive, the supply of blood which they receive having some purpose entirely different. Thus the sensibility of the muscles is by no means proportionate to the large amount of blood which they receive ; and even the substance of the brain (like that of the nerves of special sensation) is destitute of this property. So, again, the mucous membranes lining the interior of the several viscera, though supplied with blood even more copiously than the skin, are very far inferior to it in sensibility. The dependence of this endowment, however, wherever it exists, upon the continued circulation of the blood, is at once made apparent by the results of its suspension ; thus, when the main artery of a limb is tied, there is a diminution of the sensibility both of its surface and of its substance, which is so exactly proportioned to the degree in which the supply of blood is diminished, and the recovery from which takes place so precisely in accordance with the establishment of the collateral circulation, that we cannot doubt that, if the supply of blood were completely cut off', sensibility would be entirely suspended. The numbness produced by cold, in like manner, is partly due to the stagnation which it occasions in the capillary circulation in the skin ; though it is doubtless in part attributable to the immediate depressing influence of the cold upon the vital endowments of the nervous apparatus itself.\nThe general sensibility of the body may be called into activity by impressions received from objects external to it, or by causes originating in itself ; and the consequent sensations are sometimes distinguished as \u201c external\u201d and \u201cinternal.\u201d These designations are by no means logically correct; for all sensations must originate in causes external to the recipient mind; whilst, on the other hand, in order that any sensation may be felt, a certain condition of the corporeal organism must first be produced ; and this condition may be precisely the same, whether it be immediately dependent upon changes originating in the body itself, or upon changes impressed upon it from some agency external to it. . Still, however, the.terms \u201cexternal\u201d and \u201c internal \u201d sensations are sufficiently convenient, and sufficiently free from the probability of misconception, to justify the phy-","page":1163},{"file":"p1164.txt","language":"en","ocr_en":"TOUCH.\n1164\nsiologist in the employment of them ; and they will be accordingly employed in our present enquiry.\nThe external sensations received through this medium all require the absolute contact* of the body which excites them, with the itn-pressible^part ; and in this respect, therefore, there is an exact correspondence between the general sensibility and the sense of taste.\nThe force with which the impression is made, is judged of by the intensity of the sensation and the depth to which it is felt; whilst the size of the object is in some degree estimated by the extent of surface over which its contact is perceived. Both these estimates, however, are extremely vague, when they depend only upon the general sensibility of the body ; we shall hereafter see how much more precise they become, when the impressions are received through the skin, which is the special organ of touch, and when they are aided and corrected by the muscular sense. Still we find that the different modes in which external objects affect even the general sensibility, produce a very marked diversity in the character of the sensations. Thus the feeling called forth by a prick is of a very different kind from that which arises from a blow; both, again, are very distinct from that produced by a steady uniform pressure ; and all these are very different from the sensation of stretching or tearing. In the case of a prick, we have an intense impression made on the sensible part ; but this is limited to a very small spot ; whilst the impression of a blow is made with a like intensity over a much larger area, f In the case _ of steady pressure, on the other hand, the impression is made over a large surface, but is less intense ; whilst in stretching and tearing, the mechanical condition of the nerves of the part operated on is affected in a manner precisely opposite to that in which it is acted on by pressure. The sense of shock, derived from a blow extending over a large surface, is very distinct from that of the mere blow, and may be experienced when little or no pain is felt, as from the \u201cwind\u201d of a shot; and nearly allied to this is the peculiar jar which is experienced, when the shock is transmitted in such a manner as especially to affect the solid casing of the nervous centres, \u2014 as when we jump from a height, without sufficient care to alight in such a\n* There might seem to be an exception to this statement in regard to heat and cold, which are perceived when their source is at any distance that allows its radiations to affect the temperature of the body itself. But, as will presently be shown, it does not appear that the sense of temperature forms part of the general sensibility of the body ; the power of appreciating heat or cold, as such, being limited to the special organs of touch.\n+ There can be no doubt that a multitude of pricks made at the same moment, in sufficiently close proximity to prevent them from being separately distinguished, would be felt as a blow ; this being the only sensation which is received from the numerous incisions simultaneously made by the scarificator used in cupping, when it is applied to the parts of the skin endowed with the least discriminating power.\nmanner as to deaden the concussion by the elasticity of the feet, See. A succession of slight impulses rapidly following one another, gives rise to the peculiar sensation of thrill ; which, though most readily excited when the impressions are made upon the skin, may be received through the internal organs also as when we hold a vibrating body between the teeth.\nThese and other well-marked differences in the kind of information received through the general sensibility of the body, seem obviously attributable rather to diversities in the mode in which the impressions are made, than to any differences in the nature of the impressions themselves, the character of the fibres receiving them, or the endowments of the ganglionic centres in which these fibres terminate. And hence we seem to have a greater right to conclude, that the various affections of general sensibility, which are usually ranked under the common head of internal sensations, however unlike they may be one to another, are really derived from impressions which do not mutually differ so essentially as do those of the special senses from each other and from the general sense. Of this kind are the sensations of hunger and thirst, the \u201cbesoin de respirer,\u201d the genital sense, the sensation which calls for the expulsion of the urine and faeces, nausea, the feelings of oppression and of\u201c sinking\u201d at the stomach, burning, itching, tingling, formication, and others. However different these are from each other, when but slightly or moderately excited, they all merge, when more strongly called forth, into the simple consciousness of pain ; and it is further common to them all, that the nerves through which they are excited are the same as those which communicate the impressions that excite tactile sensations, and that mechanical irritation of any of these nerves occasions pain. To the foregoing may be added the \u201c muscular sense,\u201d whereby we are informed of the degree of effort put forth by a muscle; and the sense of \u201c fatigue,\u201d which seems to be a modification of this. We are not conscious either of effort or fatigue in the actions of any of the muscles over which the will has no control, such as the heart, the muscular walls of the intestinal canal, &c. ; nor in the case of those whose actions are purely rhythmical, as those of respiration. It is, in fact, only when the will is exerted, either in increasing the force of their contractions, or in antagonising them by the operation of some other muscles, that we become conscious of effort ; and we shall hereafter see that this sense is most important, in enabling us to proportion the amount of force we exert to the resistance to be overcome, and in guiding us with regard to the direction in which exertion is required. A sense of effort and of fatigue seems also to be excited in the sensorium by the mental operations of which the cerebrum is the instrument ; especially when these mental operations are no longer spontaneous, or carried on with facility, but when they require a more or less","page":1164},{"file":"p1165.txt","language":"en","ocr_en":"TOUCH.\npotent exertion of the will to keep them in activity. As we have every reason to believe that all mental exertion, like muscular force, involves (in our present state of being) a disintegration of the substance of its instrument \u2014 the brain, \u2014 there is no difficulty in understanding that this disintegration, when carried beyond a certain point, may excite the sense of fatigue (see Sleep), just as the \u201cbesoin de respirer\u201d is felt after we have withheld our respiratory movements for a few seconds, or hunger when there is a deficiency of nutritious matter in the circulating current. It has been said by Mr. Mayo, \u201c that the frame is in the completest health and condition, when the internal sensations are not excited ; the healthiest self-feeling being an absence of all inward sensation.\u201d This, however, is scarcely a sufficient account of the fact ; for, in the highest condition of health, there is not only an absence of all uneasy feeling, but a general sense of buoyancy and resiliency, difficult to describe in words, which may be characterised as the positive sense of well-being. So, on the other hand, without any positive or distinct sensation, there may be a consciousness of general discomfort, which has been expressively termed by the French malaise. These two sensations may probably be considered as originating in the condition of the blood ; the first being an indication of its purity, and of its perfect adaptation to the wants of the system ; whilst the second would seem to proceed from a slight depravation of its quality, resulting not unfrequently from the imperfect elimination of excretory matters, such as is not sufficient in itself to constitute an actual disease.\nHaving thus passed in review the principal manifestations of the general sensibility of the body, and the conditions under which they occur, we have now to proceed to the investigation of the sense of touch, as exercised by the organs specially adapted for the reception of tactile impressions.\nSense of Touch.\nSpecial Organs of Touch. \u2014 The peculiar endowments of the tegumentary surface, which enable us to draw from the impressions received through it, information of so much more varied and definite a character than we can derive through any of the structures which it invests, appear to consist principally, so far as the organ itself is concerned, in its greater sensibility (that is, in its greater aptitude for being affected by slight impressions), and in its greater power of communicating distinct impressions from points in close proximity ; but a large part of our information is dependent upon our power of giving motion to the tactile organ, and thus of increasing the force and variety of the impressions which we derive through its surface, as well as of receiving impressions of an entirely different kind, from the action of the muscles by which that motion is given. Thus, if we simply bring a solid body into contact with the point of the finger, we gain but little\n1165\ninformation of the nature of its surface, whether rough, smooth, or polished ; and we can judge nothing of its form, except in regard to that part of it in actual contact with the fingers ; and even this is but vaguely appreciated. This information may be rendered somewhat more precise by pressing the object against the finger ; as we shall then feel the impression made by elevations, points, or roughnesses, if they be sufficiently prominent and wide apart from each other ; whilst from the degree of muscular force we exert, and from the amount of yielding of which we are conscious in the object itself, we judge of its hardness, softness, elasticity, &c. But our power of discrimination is immensely increased, when we move the tactile surface on the body to be examined, or vice versa ; for, from the succession of impressions then made, we obtain our best idea of the character of the surface of the object ; whilst by the combination of the tactile impressions with the muscular sense, we judge of the relative positions and connections of its different parts, and of the form of the whole. But besides this, we find that impressions may be derived through the skin, which are not referable to a mere exaltation of its common sensibility, being apparently of a different character from any of which we become conscious through other structures ; such, especially, are sensations of temperature. Still there would seem no sufficient cause for ranking even these in a distinct category from the ordinary tactile impressions ; for the feeling of heat or cold does not differ more from that of roughness or smoothness, than does the colour of the object, as seen by the eye, from its form as distinguished by the same organ.\nThe different parts of the cutaneous surface are endowed with tactile sensibility in very different degrees ; and this variation seems closely to correspond with the degree of development of that papillary structure, which may be regarded as the special organ of touch, strictly so called. These papilles are most elevated and numerous on the tip of the tongue and the points of the fingers ; are less so on the palms of the hands and the soles of the feet ; are comparatively small and few on the integument of the limbs, and on several parts of the trunk can scarcely be discovered at all. They are described by Messrs. Todd and Bowman* as having an average length in man of T^th of an inch; and a diameter at their base, where they spring from the cuticle, of about ^|?th of an inch. Their form is somewhat conical, tapering off to a slightly rounded point. Their surface (after the removal of the epidermis) appears to be composed of the basement membrane of the cutis itself ; and their interior is composed of fibrous tissue, vessels, and nerves. In each papilla we find a small arterial twig, derived from the arterial plexus of the cutis; this, advancing towards the apex of the papilla, subdivides into two or more capillary ves-\n*\nPhysiological Anatomy, vol. i. p. 410.","page":1165},{"file":"p1166.txt","language":"en","ocr_en":"1166\tTOUCH.\nsels; and these, forming loops whose convexity lies in the summit of the papilla, reunite into venous radicles, which discharge their blood into the venous plexus of the cutis. \u201c The vascularity of the papillae,\u201d as Messrs. Todd and Bowman correctly remark, {Joe. cit.), \u201c is such, that their presence and relative size may be determined simply by the depth of the colour imparted to the skin by a good injection of its vessels ; the vascularity of the integument is, therefore, in general terms, proportioned to its perfection as an organ of touch.\u201d With regard to the nervous supply of these papillae, however, it is less easy to speak with confidence. It is derived, like the sanguiferous, from the plexus in the substance of the cutis, lying parallel to the surface ; the tubular fibres ascend, to all appearance singly, from this plexus into the papillae ; but their mode of termination or return are not distinguishable with certainty. The following are the results of the inquiries of Messrs. Todd and Bowman on this point. \u201c In regard to the presence of nerves in the papillae themselves, we can affirm that we have distinctly traced solitary tubules ascending among the other tissues of the papillae about half-way to their summits, but then becoming lost to sight, either by simply ending, or else by losing the white substance of Schwann, which alone enables us to distinguish them in such situations from other textures...........We have in numerous in-\nstances failed to detect any nerves at all within the papillae, when such were plainly visible at their base, and when, consequently, the chemical agent employed could scarcely have destroyed their characteristic structure had they been present. We incline to the belief that the tubules, either entirely or in great measure, lose the white substance when within the papillae.\u201d* With these statements, so far as they go, the writer\u2019s own observations are in entire accordance ; but he thinks that from the appearances presented by sections examined by reflected instead of by transmitted light, it may be inferred that the nervous tubules in the tactile papillae undergo a change somewhat similar to that which is said by Wagner to take place in the nervous tubuli of muscle ; namely, that whilst the white substance of Schwann is not traceable beyond a certain point, the central axis is continued further, and that this breaks up into minuter fibrillae, which form loops, like those of the capillary blood vessels, returning into the tubular fibre itself.\nIn the lower animals, as in man, it may be observed that the papillary structure is especially developed on those parts of the tegumentary surface which are especially endowed with tactile sensibility, and the impressions received through which are of important use in finding the movements of the instruments of locomotion. Thus in the quadrumana generally, both the hands and feet are thickly set with papillae ; and in those which have a\n* Op. cit. p. 412.\nprehensile tail, the surface of this organ possesses them in abundance. In the carnivorous and herbivorous mammalia, whose extremities are furnished with claws or encased in hoofs, we find the lips and the parts surrounding the nostrils to be the chief seat of tactile sensibility, and to be copiously furnished with papillae ; this is especially the case with those which have the lips or nostrils prolonged into a snout or proboscis, as in the pig, the rhinoceros, the tapir, and the elephant. In the mole, too, the papillary structure is remarkably developed at the extremity of the snout. The only part of the skin of birds on which tactile papillae have been discovered is on the under surface of the toes, and on the web of the palmipedes, where they obviously receive impressions, which guide the prehensile and other movements of the feet. It is probable, however, that the very sensitive skin which covers the greater part of the mandibles in the duck tribe, is furnished with papillae ; the tactile impressions received through this part, when the bill is plunged into mud &c., being the chief means by which the presence of food is discovered. In many lizards a papillary structure is found on the under surface of the toes ; and in the chameleon it exists, also, on the integuments of its prehensile tail. In the soft skinned batrachia, an imperfect papillary structure is more extensively diffused over the surface; but on the thumb of the male frog, and probably on that of other batrachia, there is an extraordinary development of papillary tissue at the season of sexual excitement, large papillae being formed all over it. This organisation is obviously connected with the extraordinary prehensile propensity which is then displayed by the animal, and which enables him to keep the female in his grasp during the whole period of the, discharge of the ova, in a manner which no voluntary effort could effect. In serpents and chelonians, no papillary apparatus has yet been detected ; and in fishes and invertebrata its presence has not been ascertained, although it would appear that certain parts, especially the tenta-cula around the oral orifice, are endowed with a high degree of tactile sensibility.*\nBut it is not only on the tegumentary surface of the exterior of the body, that tactile sensibility is particularly acute ; nor is the papillary apparatus restricted to it alone. In the tongue of man, we find the sense of touch remarkably developed, especially at its tip ; and of the papill\u00e6 with which its surface is beset, it is probable that some are the instruments of tactile sensibility ; whilst others minister to the gustative sense. (See Taste.) So it is probable that in all animals which have a soft fleshy tongue, furnished with papill\u00e6, and serving as the organ of taste, this organ is the instrument of tactile sensibility also.\n* The movements of these organs, or such as are excited through contact with them, can scarcely be in themselves regarded as a sufficient indication of their tactile sensibility, as they may be purely reflex, without involving consciousness of the impression.","page":1166},{"file":"p1167.txt","language":"en","ocr_en":"TOUCH.\nBesides the papillary apparatus, however, we find certain animals endowed with special organs of touch, which are constructed upon a very different plan ; consisting of a rod or filament, which is in itself insensible, but which is connected at its base with nervous fibres, in such a manner that any motion or vibration communicated to it must be transmitted to them. Such are the long stiff hairs which are known as the \u201c whiskers \u201d of the feline tribe, and which are so particularly large in the seal ; these are also highly developed in many of the rodentia, such as the hare and rabbit ; and it has been proved by experiment, that if they be cut off, the animal loses in great degree its power of guiding its movements in the dark. Thus Mr. Broughton found that whilst a kitten whose whiskers were entire was capable of threading its way blindfold out of a labyrinth in which it was designedly placed, it was totally unable to do so when its whiskers were cut off ; for it then struck its head repeatedly against the sides, ran against all the corners, and tumbled over steps placed in its way, instead of avoiding them as it did prior to the loss of its whiskers.* Tn animals whose hairs are their important instruments of touch, a true papilla, copiously furnished with nerves and bloodvessels, is found to project into the bulb of each hair. The jointed appendages to the head, known as antennes and palpi, which are possessed by most articulated animals, are undoubtedly instruments of touch, whatever sensory impressions they may receive in addition. The antenn\u00e6, when prolonged, serve to guide the movements of the animal ; the impressions which they receive at their extremities being communicated to the nerves at their base, just as a blind man judges by the stick held in his hand of the proximity of obstacles to his progress.f On the other hand, the palpi appear to minister to the cognisance of objects brought into the neighbourhood of the mouth, and to have for their chief office to guide in the selection of food. But while there are many facts which seem to indicate that the antenn\u00e6 minister to the sense of hearing, there are others which appear to point to the palpi as the special instruments of that of smell.\nConditions of the Sense of Touch. \u2014 The sense of touch, strictly so called, is exercised under conditions essentially the same as those through which the general sensibility of the\n* London Medical and Physical Journal, 1823.\nt The author is acquainted with a blind gentleman who exhibits a remarkable dexterity in the use of his stick in guiding his movements ; and he has been informed by him, that much of his power of discrimination depends upon the flexibility, elasticity, &c. of this instrument, so that, when he has chanced to l\u00f6se or break the one to which he has been accustomed, it is often long before he can obtain another that shall suit him so well. This circumstance seems to throw some light upon the re-makable varieties of conformation in the antenn\u00e6 of insects ; as it may well be imagined that each is adapted to receive and to communicate impressions of a particular class, adapted to the wants of the species.\n1167\nbody is affected. It is requisite, in the first place, that the bodies, of whose\u2018presence it takes cognisance, should be brought into actual contact with the tactile surface ; the only exception being in regard to the temperature of objects, the influence of which may be communicated by radiations from a distance. This difference, however, does not indicate any fundamental diversity such as some have imagined to exist, between the sense of temperature and that of resistance ; for, in each case, that which is perceived by the mind is the impression made upon the sensory organ ; and the change in this is excited in the one case by pressure, and in the other by heat or cold. The same organ appears to be adapted to take cognisance of both classes of impressions ; a feeling of one kind being excited, when its condition is altered by pressure; and a feeling of a different kind, when its temperature has undergone a change under the influence of calorific radiations. And the difference between these classes of sensations is not greater than that which exists among others, \u2014 whether of a general or a special kind, \u2014 which we know to be transmitted by the same nerve-fibres. Yet it would seem that, whilst there is no sufficient reason for supposing impressions of contact and of temperature to be transmitted by different nerve-fibres, we must admit that some of these fibres, either in virtue of their own constitution, of the locality of their central termination, or of the apparatus with which they are furnished at their peripheral origin, are endowed with a greater readiness to receive and transmit one or the other class of impressions. For we find that the parts whose tactile sensibility is the most discriminating, are not always those by which the keenest appreciation of changes of temperature is obtained. And, in like manner, the occasional occurrence of cases of paralysis, in which there is a total loss of one kind of sensation, whilst the other is preserved, or in which one is diminished beyond all proportion to the other, seems to show that such a change may take place in the nerve-fibres, as may indispose them to the reception and transmission of one class of impressions, whilst they are still capable of actively responding to the other.\nAfter what has been said of the necessity of the supply of blood, for the active exercise of common or general sensibility, and of the vascularity of the special tactile organs, it is not requisite to lay any further stress on this point, in relation to the sense of touch, strictly so called. Another important condition, which is probably common to the whole sensory apparatus of the warm-blooded animal, and which has been already noticed under the head of Taste, is a temperature not too far removed from that which is natural to the body. It has been shown by Professor E. H. Weber, that if the fingers or the lips be immersed for half a minute or a minute in water heated to 125\u00b0, or cooled to 32\u00b0, the power of tactile discrimination is so much impaired, that the power of distinguishing between a","page":1167},{"file":"p1168.txt","language":"en","ocr_en":"TOUCH.\n1168\nhot or cold fluid or solid body is for the time completely lost, a feeling of pain alone being experienced, which is the same whether the body be hot or cold. This, too, he found to be the case, when, instead of applying the heat or cold to the peripheral extremities of the nerve, he acted on its trunk. For this experiment the ulnar nerve was selected, as its trunk, at the elbow, lies immediately beneath the surface. After immersing the elbow in a mixture of ice and water for about sixteen seconds, Professor Weber observed that a peculiar painful sensation was experienced along the under side of the fore-arm, the wrist, the little finger, and the inner side of the ring-finger. This pain had no resemblance to that of cold. On continuing the immersion, the pain increased considerably, and eventually became almost intolerable ; then it gradually diminished, and the middle and ring-fingers became numb, as if \u201c asleep,\u201d had no longer the power of distinguishing between heat and cold, and could only imperfectly perceive the contact and pressure of bodies. *\nThe exercise of the sense of touch may be first considered under its simplest mode, namely, that in which the object is simply applied to the tactile organ ; and in this we have specially to consider the power of Tactile Discrimination, and the Sense of Temperature.\nTactile Discrimination. \u2014 A very ingenious method was devised by Professor Weberf, for determining the relative power of tactile discrimination in different parts of the skin, which is by no means accordant with their general sensibility. His mode of ascertaining this, was to touch the surface with the points of a pair of compasses, guarded by bits of cork or sealing-wax ; the eyes being closed at the same time, the legs of the compasses were approximated to each other; until they were brought so near that the points could be no longer felt to be distinct from each other. The smallest distance at which this can be perceived (entitled \u201cthe limit of confusion,\u201d by Dr. Graves), is found to differ remarkably on different parts of the cutaneous surface ; and the comparison of these diversities affords us the means of estimating, \u2014 not their relative tactile sensibility (for this it cannot measure), \u2014 but their relative discriminating power. The figures in the first column of the following Table represent these distances, as determined by Professor Weber on his own person, stated in Paris lines. The inquiry has been more recently pursued by Professor Valentin j, whose results on the whole correspond very closely with those of Weber. He found, however, a considerable extent of individual variation ; some persons being able to distinguish the points at half, or even one-third of the distances required by others. In the following table, the second column expresses the maxima\n* M\u00fcller\u2019s Archiv. 1847, p. 342.\nf De Pulsu, Respiratione, Auditu, et Tactu, An-notationes Anatomic\u00e6 et Physiologic\u00e6. Auct. H. E. Weber. Lipsi\u00e6, 1834.\n\u00ee Lehrbuch der Physiologie des Menschen, Band ii. S. 566.\nof the \u201climit of confusion,\u201d the third column the minima, and the fourth column the mean of all the observations made by Professor Valentin ; it will be observed that his maxima correspond almost exactly with the measurements of Professor Weber on his own person. In the fifth and sixth columns are shown the relative acuteness and relative obtuseness of the discriminating sense in different parts, calculated from the mean results ; \u201c the limit of confusion \u201d (0\u2018483) at the tip of the tongue being taken as P000. Thus the co-efficient of the acuteness of the discriminating sense in the palm of the hand, calculated by this standard, is O\u2019126; that of its obtuseness is 7'930. The co-efficient of acuteness for the crown of the head, is 0050 ; that of obtuseness, for the same part, is 19\u2019827. The coefficient of acuteness for the middle of the dorsal spine is 0\u2019020 ; that of its obtuseness is 50\u2019086. Or, in other words, its acuteness is only T\u00a3\u00a7^ths that of the tip of the tongue ; its obtuseness fifty times as great.\nSimilar experiments, with the like results, have been made by M. H. Belfield-Lef\u00e8vre* ; and from all these, the following general propositions may be laid down ;\u2014 1. On almost any part of the integument, the interval between the two points is more clearly distinguished, when the line which joins them is transverse (i. e. perpendicular to the axis of the body or member ), than when it is longitudinal, or parallel to that axis. According to Weber, however, the tips of the fingers and of the tongue constitute an exception to this rule; the discriminating power being greatest in them, when the line joining the points of the compasses is longitudinally directed. 2. When two points, applied simultaneously to any part of the integument, are clearly distinguished, the distance which separates them seems to be greater, in proportion to the acuteness of the discriminating sense in the part of the surface which is the subject of examination. Thus, as Weber remarks, if the points of the compasses, set at a distance of two or three lines, be applied to the cheek just before the ear, and be then moved gradually towards the angle of the mouth, the points will seem to recede from one another, in consequence of the increase of the discriminating sense in the parts to which they are applied. 3. When the two points are successively brought into contact with the skin, they seem to be at a greater distance from each other than if they are simultaneously applied ; and, in general, the distance will seem greater in proportion to the interval between their application. 4. Two points applied on different sides of the median line, seem more remote from one another than two points equally distant, but applied on one and the same side of the median line ; in other words, the power of discrimination is greater when the two points are applied on the two sides of the median line, than when they are both applied on the same side. 5. If two parts of the tegumentary surface be\n* Recherches sur la Nature, la Distribution, et l\u2019Organs du Sens Tactile. Paris, 1837.","page":1168},{"file":"p1169.txt","language":"en","ocr_en":"TOUCH,\n1169\nTABLE.\nPart of Surface.\tif\tValentin\u2019s Measurements.\t\t\tRela- tive\tRela- tive\n\t11\tMax.\tMin.\tMean.\tacute- ness.\tobtuse- ness.\nTip of the Tongue ------\tI. i\tII. 0-50\tIII. 0-40\tIV. 0-483\tV. 1-000\tVI. 1-000\nPalmar surface of 3rd phalanx of fore finger\t1\t1-00\t0-50\t0 603\t0-802\t1-248\nDo.\tdo.\tmiddle finger -\t...\t1-00\t0-37\t0-706\t0-685\t1-461\nDo.\tdo.\tring-finger\t\t1-00\t0-60\t0-723\t0-669\t1 '496\nDo.\tdo.\tthumb -\t...\t1-00\t0-50\t0-725\t0-667\t1 -500\nDo.\tdo.\tlittle finger\t\t1-00\t0-50\t0-733\t0-659\t1-517\nRed surface of under lip -\t2\t2 00\t0-50\t1 -500\t0-322\t3-130\nDo.\tupper lip -\t\t2-00\t0-50\t1 -520\t0-318\t3-145\nPalmar surface of 2nd phalanges of the fingers -\t2\t2-00\t1-25\t1-558\t0*310\t3 -223\n\t\t1st\t\t Middle of the dorsum of the tongue -\t4\t1-75 4-00\t1-50 1-50\t1 -650 I -916\t0-293 0-252\t3*414 3-964\nDorsal surface of the 3rd phalanges of the fingers\t3\t3-00\t1-75\t2-125\t0-227\t4-397\nPortion of the lips not red\t-\t4\t4-00\t1-50\t2-208\t0-219\t4-568\nTip of the nose\t------\t3\t3-00\t0-50\t2-250\t0-215\t4-655\nEdge of the tongue an inch from the tip\t...\t4 00\t1-50\t2-478\t0-195\t5-127\nLateral surface of the dorsum of the tongue\t...\t4-00\t1-50\t2-500\t0-193\t5-172\nPalmar surface of the metacarpus\t-\t3\t3-00\t1-75\t2-625\t0-184\t5-431\nEnd of the great toe\t-\t5\t5-00\t3 00\t3-250\t0-149\t6-724\nMetacarpal joint of the thumb -\t4\t4-50\t2-00\t3-333\t0-145\t6-896\nExternal surface of the eyelids -\t5\t5-00\t2-50\t3-833\t0-126\t7-930\nPalm of the hand\t-\t5\t5-00\t3 00\t3-833\t0 126\t7-930\nDorsal surface of 2nd phalanx of thumb\t5\t5-50\t2-75\t3-893\t0-124\t8-054\nDo.\tdo.\tfore finger\t\t5-50\t2-75\t3 893\t0*124\t8-054\nDo.\tdo.\tmiddle finger -\t\u2022 \u2022 \u2022\t5-50\t2 75\t3-900\t0-124\t8-069\nDo.\tdo.\tlittle finger\t\t5-50\t2-50\t3-943\t0-122\t8-158\nDo.\tdo.\tring-finger\t\t5-50\t2-75\t3-971\t0-121\t8-216\nCentre of the hard palate -\t-\t-\t-\t-\t6\t6-00\t2-00\t4 042\t0-120\t8-363\nMucous membrane of lips close to the gum\t9\t9 00\t2-00\t4-125\t0-117\t8-535\nSkin of cheek over buccinator -\t-\t-\t-\t5\t5 00\t3-25\t4-541\t0-106\t9-395\nSkin of cheek over anterior part of malar bone -\t7\t7-00\t3-00\t4-620\t0-105\t9-559\nDorsal surface of the 1st phalanges of the fingers\t7\t7-00\t4 00\t4-917\t0-098\t10-173\nPrepuce\t-------\t...\t6-00\t4-00\t5-100\t0 095\t10-552\nDorsal surface over the heads of metacarpal bones\t8\t8-00\t3-25\t5-250\t0-092\t10-862\nSkin of cheek over posteriqr part of malar bone -\t10\t10*00\t3-00\t5 286\t0-091\t10-936\nPlantar surface of metacarpal bone of great toe -\t\t7-00\t5 00\t5-875\t0-082\t12-155\nLower part of forehead -\t10\t10-00\t4-00\t6-000\t0-081\t12-414\nBack of the hand ------\t14\t14-00\t3-50\t6-966\t0-069\t14-412\nLower part of hairy scalp in occipital region\t12\t12-00\t6 00\t8-292\t0-058\t17-156\nSurface of the throat beneath lower jaw\t15\t15-00\t3-00\t8-292\t0-058\t17*156\nBack of the heel\t-\t-\t-\t-\t-\t10\t10 00\t8 00\t9-000\t0-054\t18-621\nPubes -\t--\t--\t--\t-\t. . \u2022\t14-00\t3-00\t9-200\t0-052\t19-035\nCrown of the head ------\t15\t15-00\t5-50\t9-583\t0-050\t19-827\nPatella and neighbouring part of thigh\t16\t16-00\t6-00\t10-208\t0-047\t21 -120\nAreola around nipple\t-\t\t20-00\t9-50\t12-066\t0-040\t24*964\nDorsum of foot near the toes -\t18\t18-00\t7-50\t12-525\t0 039\t25-914\nAxilla -\t--\t--\t--\t-\t\t14-00\t12-00\t13-000\t0 037\t26*897\nUpper and lower extremities of fore arm -\t18\t18-00\t7-00\t13-292\t0-036\t27-501\nBack of the neck near the occiput -\t24\t24-00\t8 00\t13-292\t0-036\t27 501\nUpper and lower extremities of leg -\t18\t18-00\t9-00\t13-708\t0 035\t28-361\nPenis -\t-\t-\t-\t-\t-\t-\t18\t18-00\t10-00\t13-850\t0 034\t28-655\nAcromion and upper part of arm\t-\t-\t-\t18\t18-00\t6-00\t13-866\t0-034\t28 688\nSacral region -------\t18\t18-00\t7-50\t14-958\t0-032\t30-948\nSternum\t-------\t20\t20-00\t8-00\t15-875\t0 030\t32-845\nGluteal region and neighbouring part of thigh -\t18\t18-00\t10-50\t16-625\t0-029\t34-397\nMiddle of fore arm, where its circumference is \"1\t30\t30-00\t8-75\t17-083\t0-028\t35*344\ngreatest -\t-\t-\t-\t-\t-\t- J Middle of thigh, do.\t-\t30\t30-00\t9-00\t17-633\t0-027\t36-482\nMiddle of cervical vertebrae\t-\t30\t30-00\t7-00\t18-542\t0-026\t38-362\nFive upper dorsal vertebrae\t-\t24\t24-00\t11-00\t19 000\t0-025\t39-310\nLower part of thorax, and over lumbar vertebrae\t24\t24-00\t11-50\t19-912\t0-022\t44-758\nMiddle of the dorsal vertebrae -\t-\t-\t-\t30\t30-00\t11-00\t24-208 II\t0-020\t50-086\n4 F\nVOL.IV.","page":1169},{"file":"p1170.txt","language":"en","ocr_en":"1170\nTOUCH.\nselected, whose relative position is subject to variation (such as the two eyelids, the two lips, &c.), and the two points of the pair of compasses be applied respectively to these two surfaces, the distance which separates them will seem to be much greater than if the two points rest at the same time on one or the other surface. 6. The same holds good, according to Weber, when the two points are applied to parts of the surface, which, though in continuity with each other, differ remarkably, either in structure, in function, or in the use habitually made of them ; thus, the points will be more clearly distinguishable, and will therefore seem to be more distant from each other, when one is applied to the inner surface and the other to the red outer surface of the lips, than when they are both applied to the latter, although its discriminating power is much greater than that of the former ; and the same holds good of the margin and dorsum of the tongue, the palmar and dorsal surfaces of the last phalanges of the fingers, &c.\t7. The\ndiscriminating sense is more acute in the integuments of the head, than in those of the trunk ; and on the face, its acuteness diminishes as the distance from the mouth increases. 8. The tactile discrimination of the integuments of the limbs augments with the distance of the part from the axis of the body; it is less in the integuments of the trunk, than in those of the members.\nThe power of tactile discrimination may be conceived to depend in part upon the mode in which the ultimate nerve-fibres are distributed in the skin, being greater in proportion as contiguous parts are supplied from distinct central sources, and less when the central terminations of their nerve-tubes are the same. Thus, if two impressions be made along the course of the same nerve-tube, they will not be felt as two, but as one , and this probably holds good of the parts of the integument supplied with branches from the central axis of any one tube. On the other hand, whenever two impressions be made upon two distinct nerve-tubes, or on the branches proceeding from them, they will probably be felt to be double ; and the distance at which these impressions seem to the tactile sense to be, appears to have a relation to the distinctness of the central connections of these nerve-tubes, as appears from the fact that the \u201c limit of confusion \u201d is less across the median line than on either side of it ; that it is less between two parts (such as the lips and eyelids) whose nervous supply is known to be distinct, than on either part separately ; and that it is less between two parts whose nervous supply may be presumed, from their difference of function, to be distinct (as the inner and outer surfaces of the lips), than on either part separately. More-ever, it would not seem to be improbable that one use of the plexuses from which the limbs are supplied, is to produce such an intermingling of the fibres from different ganglionic centres, that contiguous portions of the integument shall be connected with cen-\ntres very remote from each other, and their discriminating power thus augmented. No such intermingling takes place in the nerves which supply the trunk, and the tactile discrimination of its integument is (as we have seen) vastly inferior to that of the extremities. Thus it may happen that the common sensibility of two parts may be the same, whilst their power of tactile discrimination may differ considerably ; and we may even have the common sensibility greatest where the tactile discrimination is least, \u2014 as we experience, for example, on the integument of the face, which is far more sensitive to a blow, and especially to a \u201c fillip,\u201d than is the integument of the palmar surface of the fingers, although greatly inferior to them in discriminating power. The actual nervous supply, and the consequent sensibility, of a part, may be greater in such cases ; but the unity, or close approximation, of the source from which this proceeds, may prevent its discriminating power from augmenting in the same proportion.\nIn like manner, we find that the tactile discrimination of different parts bears no relation whatever to that peculiar modification of common sensibility (which yet appears the exclusive attribute of the external integuments) through which the feeling of \u201c tickling \u201d is excited. For the parts which are most susceptible to this feeling, such as the axillae and the soles of the feet, are possessed of a very low degree of discriminating power, and those which possess this power in the highest degree (such as the tips of the fingers) are the least \u201cticklish.\u201d Further, it is worthy of notice that the parts through which that peculiar sensation, which we have termed the genital sense, is specially excited,\u2014namely, the penis and the mammary areola,\u2014 are remarkable rather for the obtuseness than for the acuteness of their power of tactile discrimination.\nThat it is only through the skin and those parts of its internal reflexions which are in closest proximity with it (especially the lining of the mouth and nostrils), that we can discriminate tactile impressions, appears from this ; that although the internal mucous and serous surfaces, the fibrous membranes, and the parenchyma of many organs, &c. &c., are all capable of becoming acutely sensible to pain when irritated or inflamed, yet no foreign substance is ever distinctly felt by the touch through these parts. Thus, although a sensation of a pleasing or a painful nature is excited by certain substances immediately upon being swallowed, all consciousness of their presence (so far as it is dependent upon the sense of touch) soon ceases, and cannot be again recalled by the utmost exertion of the will. Further, a foreign substance, lodged in the alimentary canal, or in the trachea, may give rise to the greatest possible distress, through the irritation it produces ; but though it thus acts upon the nerves of the parts immediately in contact with it, these nerves convey no idea to the sufferer of the shape or size of the body, or of any other of its","page":1170},{"file":"p1171.txt","language":"en","ocr_en":"TOUCH.\t1171\nphysical qualities, concerning which we receive information through the sense of touch.\nSense of Temperature. \u2014 This sense is called into action when there is a difference between the temperature of the sensory organ and that of the surrounding medium, or of substances with which it is specially brought into contact. It is one of which the intensity is determined, more perhaps than that of any other sensation, rather by the relative than by the absolute condition of the body which excites it. Thus, if one hand be immersed for a time in hot water, and the other in cold, and both then be plunged into tepid water, this will seem cool to the former and warm to the latter. So, again, a person coming out of cold air into an atmosphere of moderate temperature, derives from it the feeling of genial warmth, whilst another, coming into the very same atmosphere from one much hotter, complains of its chillness. Again, when the temperature of different substances is compared by the hand, the sense is not so much influenced by the absolute amount of caloric possessed by each, as by their power of imparting cold or heat to the sensory organ. Hence substances which are good conductors (such as metals or marble) are felt to be colder than those which conduct heat badly (such as wood), although really of the same temperature, because they draw off the heat of the sensory surface more rapidly ; whilst, on the other hand, if both be warmer than the sensory surface, the best conductors will seem to be the hottest, because their caloric is most readily imparted. Further, the sense of temperature is influenced in a remarkable degree by the extent of surface on which the impression is made. Every one is familiar with the fact that hot water in which a single finger may be held without inconvenience, will be felt intolerably scalding when the whole hand is immersed in it. And it has been shown by Professor Weber, that if one vessel of water be heated to 98\u00b0 and another to KH0, and the whole of the hand be immersed in the former, while the finger alone is immersed in the latter, a wrong judgment of their relative temperatures will be probably given, that which is really the cooler being pronounced the hotter, on account of the larger extent of surface on which it acts. This mistake was made in soqie of his experiments, when the difference was as much as eight degrees ; the cooler water being at 98\u00b0, and the hotter at 106\u00b0, and yet the former being esteemed the hotter. So, again, the immersion of the entire hand enables minute differences of temperature to be detected, which could not be recognised by the immersion of a single finger. By the former method, a difference of only one-third of a degree may be distinguished ; the entire hand being immersed, repeatedly and successively, in two vessels of water, differing only that much in their relative warmth. But it is remarked by Professor Weber, that these minute differences are best detected when the medium examined does not fall short of, or exceed\nvery considerably, the usual temperature of the body ; just as the ear can best perceive a difference of tone in sounds which are neither very acute or very grave.*\nIt is a remarkable fact, discovered by Professor Weber, that the left hand is in most persons more sensible to variations of temperature than the right. Thus, when the hands of a person lying in bed, and haying exactly thq same temperature, are plunged each in a separate vessel of hot water, the left hand is believed to be in the hotter medium, although the water in which it is immersed is really one or two degrees colder than the other. This difference is the more remarkable, as the power of tactile discrimination is usually greater in the right hand ; and it is attributed by Professor Weber to a difference in the thickness of the epidermis, the left hand usually having a thinner epidermis than the right, especially in the palm, because it is less used. But this will only apply to the hand ; and since (as will be presently shown) we possess a greater power of discriminating pressures through the entire surface of the left side than through that of the right, it would seem much more probable that there is an original difference in the tactile endowments of the two sides respectively. There is certainly a strongly marked difference between different parts of the trunk in regard to their sensibility to temperature, as is experienced by those who sponge themselves over with cold water immediately on leaving their bed in the morning. In the writer\u2019s case, the parts most sensitive to the cold are in the centre of the dorsal region behind; in front, between the lower end of the sternum and the umbilicus ; and the corresponding portions of the flanks. These spots are among the parts of the integument least possessed of tactile discrimination ; and yet the cold sponge passing over them seems to be much lower in temperature than when it is applied to other parts.\nSome further experiments have recently been made by Professor Weber, to determine whether the sense of temperature is received through any other channel than the sensory apparatus contained in the integuments.f The fii^t means of which he availed himself for deciding this question, was that afforded by the results of accident or surgical operations, in which a portion of skin has been left deficient. Thus, in three cases in which a large portion of the skin had been destroyed by a burn, and in which healing had not advanced so far as to renew the organ of touch, it was found that no correct discrimination could be made between two spatulas, one of them at a temperature of from 48\u00b0 to 54\u00b0, the other of from 113\u00b0 to 122\u00b0, which were brought into\n* He further remarks, that the comparison between two temperatures can be best made when the impressions are not simultaneously made upon two different parts, but are made in quick succession upon the same part ; as mentioned hereafter to be the case in regard to weights.\nf M\u00fcller\u2019s Archiv. 1849. Heft, iv. s. 273\u2014283.\n4 F 2","page":1171},{"file":"p1172.txt","language":"en","ocr_en":"1172\tTOUCH.\ncontact with the denuded surface ; so that one of these patients thrice affirmed that he was being touched with the cold body when it was the warm, and the reverse. But when the spatula was in one instance made somewhat warmer, and was brought into contact with the unskinned surface, the patient felt, not heat but pain. Another means of gaining information on this point is afforded by the ingestion or injection of a large quantity of warm or cold fluid into the stomach or intestinal canal. Thus Professor Weber states, that after drinking a tumbler of water at 32\u00b0, he felt the cold water in the mouth, in the palate, and in the pharynx, as far as the limits of the sense of touch ; but that the gradual passage of the cold water into the stomach could not be perceived. There was, it is true, a slight sensation of cold in the gastric region; but as it only occupied the situation of the anterior wall of the stomach, it was attributable to the abstraction of heat from the abdominal integuments in contact with this. In an opposite experiment, the author drank quickly three glasses of milk, the temperature of the first of which was 158\u00b0, that of the second 145\u00b0, whilst that of the third was intermediate between the two. The sensation of heat could not be traced lower down than that of the cold in the previous experiment. At the moment when the fluid entered the stomach, there was a feeling which remained for some time, but which could not be distinguished as heat, being mistakeable for cold. In order to ascertain the sensations produced in the large intestine by cold water, an injection of 14 ozs. of water of the temperature of 65\u00b0 was thrown up the rectum, but scarcely any sensation of cold could be perceived from it. In another instance, 21 ozs. of water at the same temperature was thrown up, without any resulting sensation of cold. In both these cases, on the return of the enema a few minutes afterwards, a distinct feeling of cold was experienced at the anus. When water of so low a temperature as 45\u00a3\u00b0 was injected, the first feeling excited was a sensation of cold in the immediate neighbourhood of the anus, and then a feeble movement in the bowels ; but a little time afterwards, there was a faint sensation of cold, especially in the anterior wall of the abdomen. This sensation, however, remained after the return of the water ; and may hence be attributed to the abstraction of warmth from the abdominal integuments, which was proved to take place, the temperature of the surface being lowered 3 degrees. So, again, if the cavity of the nose be filled with cold water, the coldness is only perceived in the parts of the cavity which are most endowed with the proper tactile sense, namely, the neighbourhood of the nostrils and of the pharynx ; and it is not at all discernible in the higher part of the cavity, which is especially subservient to the olfactive sense. [See Smell.] But when the water injected is very cold (e. g. 41\u00b0), a peculiar pain is felt in the upper part of the nasal fossae, extending to the regions of the forehead and lachrymal\ncanals ; this pain, however, is altogether different from the sense of coldness.\nFrom the foregoing experiments it appears fair to conclude, that the sensory nerves have no power of receiving impressions arising from difference of temperature, unless those impressions are communicated through a special organ ; but they afford no adequate ground for the supposition, that a set of nerve-fibres is provided for their transmission, distinct from those which minister to common sensation. This conclusion is confirmed by the fact, that we cannot excite impressions of heat or cold by direct application to the trunks of nerves which we know must conduct such impressions. Thus the parts of the skin immediately beneath which lie large nerve-trunks, are not more sensitive to moderate heat or cold than any other part ; whilst a greater degree of either is felt as pain, not as a change of temperature. Thus, as we have already seen, a mixture of ice and water, applied over the ulnar nerve, affects it in fifteen seconds, and produces severe pain, having no resemblance to cold, such as cannot be excited by the same cold applied to any other region. So the nerve of the tooth-pulp is equally and similarly affected by water of 43\u00b0 and of 112\u00b0; either application causing a pain exactly similar to that excited by the other, or that produced by pressure.*\nWe have now to consider those more complex modes of exercise of the sense of touch which require the conjoint exercise of the \u201c muscular sense;\u201d and as this is a modification of the general sensibility, which may perhaps be regarded as being as special or peculiar in its relations to the muscular system as the sense of touch (properly so called) is to that of the skin,] it will be desirable to examine, in the first instance, into its modus operandi.\nMuscular Sense. \u2014 It may be stated as a general fact, that all voluntary muscular contraction must be guided and controlled by sensation ; and in the majority of cases, the controlling sensation is derived from the muscles themselves, of whose condition we are rendered cognisant by the sensory nerves with which they are furnished. The proof of this necessity is furnished by the entire want of power to make or sustain voluntary efforts, when the guiding sensation is deficient. Thus, in complete anaesthesia of the lower extremities, without loss of muscular power, the patient is as completely unable to walk, as if the motor nerves had also been paralysed, unless the deficient sensorial guidance be replaced by some other ; and in similar affections of the upper extremities, there is a like inability to raise the limb or to sustain a weight. Butin such cases, the deficiency of the \u201c mus-\n* It is remarkable that the same should be true of the impressions received through the skin itself, when they pass beyond certain limits of intensity ; thus, the sensation produced by touching frozen mercury is said to be not distinguishable from that which results from touching a red-hot iron..","page":1172},{"file":"p1173.txt","language":"en","ocr_en":"TOUCH.\t1173\ncular sense\u201d maybe made good by the visual; thus, the patient who cannot walk, because he cannot feel either the contact of his foot with the ground, or the muscular effort he is making, can do so if he looks at his limbs ; and the woman who cannot feel the pressure of her child upon her arras, can yet sustain it as long as she keeps her eyes fixed upon it, but no longer, \u2014 the muscles ceasing to contract, and the limb dropping powerless, the moment that the eyes are withdrawn from it. There are two groups of muscular actions, however, which, although as voluntary in their character as the foregoing, are yet habitually guided by other sensations than those derived from the muscles themselves. These are, the movements of the eyeball, and those of the vocal apparatus. The former are directed (as Dr. Alison has well shown*) by the visual sense, by which the action of the muscles is guided and controlled in the same manner as that of other muscles is directed by their own \u201c muscular sense and hence it happens that, when we close our eyes, we cannot move them in any required direction, without an effort that strongly calls forth the muscular sense, by which the action is then guided. In persons who have become blind after having once enjoyed sight, an association is formed by habit between the muscular sense and the contractile action, that enables the former to serve as the guide after the loss of the visual sense ; but in those who are born perfectly blind, or who have become so in early infancy, this association is never formed, and the eyes of such persons exhibit a continued indefinite movement, and cannot by any amount of effort be steadily fixed in one spot, or be turned in any definite direction. A very small amount of the visual sense, however, such as serves merely to indicate the direction of light, is sufficient for the government of the* movements of the eye-ball.\nIn the production of vocal sounds, again, that nice adjustment of the muscles of the larynx, which is requisite to give forth determinate tones, is ordinarily directed by the auditory sense; being learned in the first instance under the guidance of the sounds actually produced ; but being subsequently effected voluntarily, in accordance with the mental conception (a sort of inward sensation) of the tone to be uttered, which conception cannot be formed, unless the sense of hearing has previously brought similar tones to the mind. Hence it is that persons who are born deaf, are also dumb. They may have no malformation of the organs of speech ; but they are incapable of uttering distinct vocal sounds or musical tones, because they have not the guiding conception, or recalled sensation, of the nature of these. By long training, however, and by imitative efforts directed by the muscular sense of the larynx itself, some persons thus circumstanced have acquired the power of speech ; but the want\n* Anatomical and Physiological Inferences from the Study of the Nerves of the Orbit, in Trans, of Roy. Soc. Edinb., vol. xv.\nof a- sufficiently definite control over the vocal muscles is always very evident in their use of the organ. It is very rarely that a person who has once enjoyed the sense of hearing, afterwards becomes so completely deaf, as to lose all auditory control over his vocal organs. An example of this kind, however, has been made known to the public by a well known author, as having occurred in himself ; and the record of his experiences * contains many points of much interest. The deafness was the result of an accident occurring in childhood, which left him for some time in a state of extreme debility ; and when he made the attempt to speak, it was with considerable pain in the vocal organs. This pain probably resulted from the unaccustomed effort which it was necessary to make, when the usual guidance was wanting ; being analogous to the uneasiness which we experience when we attempt to move our eyes with the lids closed. His voice at that time is described as being very similar to that of a person born deaf and dumb, but who has been taught to speak. With the uneasiness in the use of the vocal organs was associated an extreme mental indisposition to their employment; and thus, for some years, the voice was very little exercised. Circumstances afterwards forced it, however, into constant employment; and great improvement has subsequently taken place in the power of vocalisation, evidently by attention to the indications of the muscular sense. It is a curious circumstance, fully confirming this view, that the words which had been in use previously to the supervention of the deafness, are still pronounced (such of them, at least, as are kept in employment) as they were in childhood ; the muscular movements concerned in their articulation being still guided by the original auditory conception, in spite of the knowledge derived from the information of others, that their pronunciation is erroneous. On the other hand, all the words subsequently learned are pronounced according to their spelling ; the acquired associations between the muscular sensations and the written signs being in this case the obvious guide.\nThe perception of \u201ceffort\u201d which we derive through the impressions made on the muscular sense, is one which, as we shall presently see, is of immense value, in combination with simple tactile sensation, in informing us of the sensible properties of external objects. In its simplest exercise, however, it enables us to appreciate the degree of muscular force which is being exerted ; and excites in our minds our most definite idea of power. It is true that we might, by the exercise of our other senses, have arrived at the conception of a tendency in bodies to attract one another, or to communicate motion one to another ; but the notion of the force with which they do so is entirely founded, directly or indirectly, upon\n* See the \u201c Lost Senses,\u201d by Dr. Kitto ; vol. i. chapters 2 and 3.\n4 F 3","page":1173},{"file":"p1174.txt","language":"en","ocr_en":"1174)\tTOUCH.\nthe conception of the muscular exertion which would be required to produce or to antagonise the movement. Thus it is, too, that when we are about to make a muscular effort, the amount of force which we put forth is governed by the mental conception of that which will be required, as indicated by the experience of former sensations ; just as the contractions of the muscles of vocalisation are regulated by the conception of the sound to be produced. Hence if the weight be unknown to us, and it prove either much heavier or much lighter than was expected, we find that we have put forth too little or too great a muscular effort.\nIt is through the \u201c muscular sense,\u201d in combination with the visual and tactile, that those movements are regulated, which are concerned alike in ordinary progression, and in the maintenance of the equilibrium of the body. That the visual sense has, in most persons, a large share in this regulation, is evident from the simple fact that no one who has not been accustomed fto the deprivation of it can continue to walk straightforwards, when blind-folded, or in absolute darkness, towards any point in the direction of which he may have been at first guided. But the blind man, who has been accustomed to rely exclusively upon his muscular sense, has no difficulty in keeping to a straight path ; and moves onwards with a confidence which is in remarkable contrast with the gait of a man who has been deprived of sight for the occasion only. In fact, as Mr. Mayo has well remarked *, in our ordinary movements, \u201c we lean upon our eyesight as upon crutches.\u201d And when our vision, instead of aiding and guiding us, brings to the mind sensations of an antagonistic character, our movements become uncertain, from the loss of that power of guidance and control over them which the harmony of the two sensations usually gives. Thus a person unaccustomed to look down heights feels insecure at the top of a tower or a precipice, although he knows that his body is properly supported ; for the void which he sees below him contradicts (so to speak) the tactile sensations by which he is made conscious of the due equilibrium of his body. So, again, any one can walk along a narrow plank which forms part of the floor of a room, or which is elevated but a little above it, without the least difficulty, and even without any consciousness of effort. But let that plank extend across a chasm, the bottom of which is so far removed from the eye that the visual sense gives no assistance ; and even those who have braced their nerves against all emotional distraction feel that an effort is requisite to maintain the equilibrium during the passage over it;\u2014that effort being aided by the withdrawal of the eyes from the abyss below, and the fixation of them on a point beyond, which at the same time helps to give steadiness to the movements, and distracts the mind from the sense\n* Outlines of Physiology, p. 355.\nof its danger. The degree in which the muscular sense is alone sufficient for the guidance of such movements, when the mind has no consciousness of the danger, and when the visual sense neither affords aid nor contributes to distract the attention, is remarkably illustrated by the phenomena of Somnambulism; for the sleep-walker traverses, without the least hesitation,, the narrow parapet of a house, and crosses narrow and insecure planks, chambers, roofs, &c., under circumstances that clearly indicate the nature of the guidance by which they are directed (see Sleep, p. 694). The dependence of our ordinary power of maintaining our equilibrium upon the combination of the guiding sensations derived through the sight and the touch, is further well illustrated, as Mr. Mayo has pointed out *, by what happens to a landsman on first going to sea. \u201c It is long before the passenger acquires his \u2018 sea legs.\u2019 At first, as the ship moves, he can hardly keep his feet ; the shifting lines of the vessel and surface of the water unsettle his visual stability ; the different inclinations of the planks he stands on, his muscular sense. In a short time, he learns to disregard the shifting images and changing motions, or acquires facility in adapting himself (like one on horseback) to the different alterations in the line of direction in his frame.\u201d Before this power, however, has been gained, the passenger has usually to experience most distressingly that peculiar feeling of want of support, which is consequent upon the pitching and rolling of the ship, but more particularly upon the former. As the part of the vessel on which he is standing, sitting, or lying, rises beneath him, there is a comfortable sense of support ; but as it sinks, the want of support is most disagreeably felt ; and the continual repetition of this sensation gives rise to nausea and vomiting. The tendency is increased by the sight of continually shifting lines and surfaces, which of itself, with many individuals, disposes to the same state ; and hence it is that the sickness may often be kept at bay by simply closing the eyes, so as to exclude these objects ; whilst, on the other hand, the effort to stand or walk only serves to augment the distress, by increasing the sense of instability. \u2014 The giddiness and nausea produced by rapidly turning round, are the results of the same sensations. They are usually excited more through the visual than through the tactile sense ; but that the latter is of itself quite sufficient to produce them, is obvious from the fact that they are experienced when the eyes are closed, as well as by blind persons. The feeling of disturbed equilibrium is more persistent than most other sensations ; thus when a person has turned round quickly several times in succession, and then suddenly stops, he feels a whirling sensation, which excites a disposition to continued motion in his limbs, and the surrounding objects appear to move before\n* Loc. cit.","page":1174},{"file":"p1175.txt","language":"en","ocr_en":"TOUCH.\t1175\nhis eyes. But if, as Mr. Wheatstone has ointed out, the person who is turning round olds a large sheet of paper before and near his face, so as to exclude all sight of the room, and fixes his eyes upon a point \u2014 a letter, for instance, in the middle of the paper, \u2014 when he stops, he finds his head perfectly steady, and the surrounding objects have no apparent motion ; but his legs feel unsteady, as if they continued actually turning round. And it is thus clearly proved that the cause of the giddiness lies in the affection of the senses, and not (as is usually imagined) in disturbed cerebral action.\nSense of Weight. \u2014 This is usually derived from a double source ; namely, the impression made upon the cutaneous surface by the simple pressure of the body; and the consciousness of the muscular effort employed to resist that pressure. The latter enables us to compare the weights of different bodies much more accurately than the former, which is liable to excite fallacious ideas. The extent of surface, for example, which is in contact with the skin, greatly modifies the estimate of the pressure of a heavy body ; the body feeling lightest when its pressure is distributed over a larger surface, and vice versa. Thus, a truncated cone seems heavier when it rests (without any effort being made to raise or support it) upon its small extremity, than when it rests upon its large extremity on the same part of the surface. At first sight this fact appears altogether antagonistic to the one just stated with regard to the sense of temperature, the impressions on which are more powerful when they are made over a large than over a small surface. But it is to be borne in mind, that in the latter case an absolutely larger amount of calorific influence is exerted, when the large surface is exposed to the action of heat ; whilst in the former, the amount of pressure is really the same, whether it be distributed over a larger or a smaller area. The experiments of Weber on the relative information derived from the mere sense of pressure, and from the sense of muscular effort, in the appreciation of weights, are very instructive. He found that if the two hands of the same individual be placed upon cushions, and unequal weights be placed upon the right and left hands respectively, the eyes being kept shut, it will not be possible to say on which hand the heavier weight lies, unless the difference be very considerable ; but a comparatively small amount of difference is at once discriminated, when a muscular effort is made to lift the hands from the cushions. _ This power of comparison is capable of being rendered more exact by practice ; so that men accustomed to estimate weights by poising them in their hands, will readily distinguish between two which differ only by one-thirtieth part. It is found that the power of comparison is much greater (as in the estimation of temperature) when the impressions are successively, than when they are simultaneously made, provided that the interval be not too long. Thus in the comparison of two weights, the greatest\nnicety is attained by poising the one, and immediately afterwards the other, in the same hand ; but the intervention of a few seconds between the poising of the first and that of the second does not prevent their accurate comparison. The interval may amount to twenty seconds, and yet a just estimate may still be made ; but when it amounts to forty seconds all accuracy is lost. Professor Weber has further ascertained, that, in the estimation of weights by their simple pressure on the surface, the left side and extremities have usually a more acute perception than the right ; for out of fourteen individuals, he found this to be the case in eleven ; in two, the contrary was observed ; whilst in one, no difference was perceptible.\nSense of Direction. \u2014 The combination of the muscular with the simply tactile sense enables us also to judge in some degree of the direction of the pressure. Of this we gain no information whatever from the tactile sense alone, which always suggests the idea that the pressure is made vertically to the surface, when it is not corrected by the sense of muscular effort called forth to antagonise it. The following example, given by Weber, shows how completely involuntary may be this effort, yet how large a share it has in communicating to us the information we derive from an impression, of whose direction we are rendered cognisant. When a hair of the head is pulled, he remarks, we can judge perfectly well of the direction of the traction ; this power of discrimination is not, however, derived (as might at first be supposed) through the sensation originating in the bulb of the hair, but from the sense of the muscular effort which is called forth to antagonise the traction, and to keep the head steady during its continuance. If w'e prevent these muscles from being called into play, by steadily holding between the hands the head of the person operated on, and if we also prevent the traction from calling forth the muscular action of the scalp, by surrounding the point from which the hair is pulled with a firm pressure by the fingers, we find that the discriminating power is completely lost ; the subject of the experiment being totally unable to distinguish the direction from which the hair is pulled.\nIt is by this combination, too, that we judge of the rate and direction of the passive motion of our bodies, when we have no other means of guidance. If, for example, a person be seated in a carriage, with his eyes closed, and the carriage be suddenly put in motion, the inertia of his body causes it to be thrown in the contrary direction ; and, in order to recover and sustain its equilibrium, a muscular effort is required, which is greater in proportion to the rate of motion. If the motion continue uniform, however, this effort becomes so habitual that he ceases to be conscious of it ; and he only becomes cognisant of the motion by its cessation, the equilibrium of the body being then again disturbed by its inertia, which tends to impel it in the direction in which it was previously moving, so as to re-","page":1175},{"file":"p1176.txt","language":"en","ocr_en":"1176\nTOUCH.\nquire the effort of a contrary set of muscles for the maintenance of the erect position.\nMental Phenomena connected with the Sense. \u2014 The interpretation which the mind puts upon the impressions made by external objects upon the tactile organs, is partly the result of intuition, partly of experience. Thus we intuitively refer an impression made upon any part of a sensory nerve in its course, to the peripheral extremities of that nerve, or (as in cases of amputation) to the part from which they should normally arise. So, again, if a part of the body be removed from its usual position and connections (as in the Taliacotian and various other operations of plastic surgery), impressions made upon it continue to be referred to its original seat, so long as it retains any nervous connection with it, and until new connections have been formed with the nerves of the part to which it has been transferred. So, again, when our members are in an unaccustomed position, we still, unless our attention be directed to the fact, interpret impressions made upon them as if they were in their ordinary relation to each other, and may thus be altogether misled : \u2014 as in the experiment mentioned by Aristotle, of rolling a pea or other globular body between two fingers of one hand, which are crossed instead of lying parallel, so that the surfaces that are usually most distant are brought into proximity with each other ; the sensation then received is that of a distinct convex body opposed to each of these surfaces, so that the single body seems to be double ; whereas, if the pea were rolled between the two surfaces which are usually and normally approximated, it is felt but as a single globe. This intuitive reference is obviously analogous to that by which we judge of the relative situations of visual objects, from the direction in which their rays impinge upon the retina, or from the muscular sensations received from the muscles of the orbit.\nIn a large proportion of other cases, however, our interpretation of our tactile sensations, especially of all those which relate to the configuration, density, &c. of external objects, is based on experience ; and those who watch the eagerness with which the infant grasps and examines by its touch every attractive object within its reach, are at no loss to perceive how the experience thus early interwoven (as it were) with the mind, in combination with that derived through the visual sense, comes to supply the place of the congenital intuitions of the lower animals, and to cause the tactile and visual perceptions to be henceforth so indelibly associated, that each is continually suggesting the other. Thus, the notion of \u2019projection, which we derive through the sight, comes to be associated with that of solidity, which we receive through the touch ; and the visual notion of polish is so closely connected with the tactile notion of smoothness, that the one almost necessarily suggests the other. There is abundant evidence, however, that there is no necessary or intuitive connection between the ideas which\nwe derive through these two senses respectively ; but that this connection is acquired by the consentaneous exercise of them. Thus, from observations made upon persons born blind, when visual power has been first obtained, it is certain that the notions of form previously acquired by the touch do not aid in the visual discrimination or recognition of objects : so that, for example, if any such person had previously learned to distinguish a sphere, a cube, and a pyramid, by the touch, he would not be able to say which was which by looking at them, until he had learned by experience to associate the two classes of perceptions : and, conversely, we cannot but believe that the same result would occur, if a person whose notions of the external world were derived from the sight alone, were suddenly and for the first time to become endowed with the sense of touch.\nIt is, in fact, no less clear in regard to the sense of touch than it is in regard to vision, that it is not the sentient organ (as we are accustomed to term it), but the mind, which really perceives ; and that all the notions which wre derive through this sense with respect to external objects, whether they be of the most general kind or of a more particular nature, are altogether distinct from the sensations themselves. It has been well remarked by Professor Alison, that \u201c one decisive proof of this being the true representation of this part of our mental constitution is obtained by attending to the idea of extension or space, which is undoubtedly formed during the exercise of the sense of touch, but which is no sooner formed than it \u2018 swells in the human mind to infinity,\u2019 to which, certainly, no human sensation can bear any resemblance.\u201d* So, again, the elementary notion of an external universe as something distinct from the individual self, is altogether distinct from the sensations which excites it. All that the mind is conscious of, is -a change in the condition of the corporeal organism ; and the reference of the source of this change to some external agency is a mental process in which the action of the purely sensorial apparatus has no concern.\nIt has been thought by some that the notion of an external world depends more upon the sensations received through the touch, than upon those of any other kind. But there does not seem to the author to be any reason for considering that simply tactile impressions are more necessarily or intuitively recognised as proceeding from an external source than are the visual, olfactive, auditory, or gustative. But, as already shown, it is from the muscular sense that we derive the idea of force, involving resistance to our own voluntary efforts ; and it would seem to the writer to be on this notion that our belief in the existence of an universe external to ourselves most securely rests.\nThe active co-operation of the mind is required, not only for the formation of the\n* Outlines of Physiology, 3rd ed. p. 290.","page":1176},{"file":"p1177.txt","language":"en","ocr_en":"TOUCH.\t1177\nnotions so immediately springing from sensations as to be often confounded with them, but also for the reception of the sensory impressions themselves. Until, in fact, the mind has been affected by these impressions, no sensation can be said to exist ; and that of which the mind takes cognisance is not the external object but the impression produced by it, and not the direct or immediate impression produced by it upon the organ which first receives it, but the change in the senso-rium consequent upon this. (See Sensation.) That this is the true account of the process is now universally admitted both by the psychologist and the physiologist ; and it is placed beyond all reasonable question by the occurrence of those subjective sensations, which, until their indications are corrected by experience, may suggest the idea of an external source, with such vividness and definiteness, that the objective unreality can scarcely be credited. In some instances the excitement of these subjective sensations appears due to the occurrence of a change in the part in which they are felt, which simulates that which would be produced by an external impression ; as in the case of the sensation of extreme heat, which is often experienced in inflammation to a degree far beyond that which the actual exaltation of temperature would account for ; and the pain, of various kinds, often resembling that inflicted by external injuries, which is the result of morbid changes in the part to which it is referred. But in other cases they are clearly referable to changes taking place in the course of the nerve-trunk to the sensorium, which simulate those which would naturally occur in it when it is the conductor of an external impression ; of this several examples have already been given. Or, again, they may be due to a change purely sensorial ; as in the various cases of \u201c radiation of sensations \u201d elsewhere alluded to (see Sensation),- or, as in the sensations of nausea, of shuddering, of tickling, of pain, &c., which are frequently excited by changes purely mental. The degree of intensity, again, with which actual sensations are felt, depends as much upon the state of the mind as upon that of the corporeal organism. Thus, if we experience a slight itching in the skin, and direct our thoughts to it, we are speedily annoyed by its increase ; whilst, if we steadily fix our thoughts upon some other object, we are soon unconscious of the irritation. On the other hand, the complete absorption of the mind in some train of thought which engrosses its attention, may render the individual unconscious of impressions that would ordinarily induce severe pain. This is remarkably seen in cases of natural and artificial somnambulism (see Sleep) ; and it is probable that in many of the cases in which insane patients have inflicted severe wounds upon themselves, without appearing to feel pain, the cause of the immunity from suffering is to be found in the entire possession which some dominant feeling or idea has of their consciousness, so that\nthey are not cognizant of any external impressions but such as harmonize with it. Even in ordinary cases, it is well known that a severe injury suddenly inflicted, is much less felt at the moment than a far slighter injury of which the mind has been in expectation ; thus, a limb has been carried away by a cannon-ball, or the chest traversed by a bullet, with far less consciousness of pain than is produced by the trivial incision made in ordinary venesection.\nImproveability of the Sense of Touch. \u2014 The mental participation in the phenomena of tactile sensation is further rendered obvious by the improvement in discriminating power which results from continual attention to its indications. Of this we have examples in the case of certain artisans, whose employments require them to cultivate their tactile discrimination ; thus, the female silk-throwsters of Bengal are said to be able to distinguish by the touch alone twenty different degrees of fineness in the unwound cocoons, which are sorted accordingly ; and the Indian muslin-weaver contrives, by the delicacy of his touch, to make the finest cambric in a loom of such simple construction, that European fingers could at best propose to make a piece of canvas in it. The improvement in tactile discrimination is more especially seen, however, in those individuals whose dependence upon it is increased by the loss or deficiency of other senses ; and especially by blindness, congenital or acquired. Whilst it is doubtless to be attributed, in great part, to the concentration of the attention and of the powers of recollection and comparison upon the sensations which are brought (as it were) to the mind, it may not seem altogether improbable that the improvement may in part depend upon an increased development of the tactile organs themselves ; resulting from that augmented nutrition which would be the natural consequence of the frequent use of them, and of the increased flow of blood that seems to take place towards any part on which the attention is continually fixed. Certain it is, that many blind persons can not merely obtain as definite and accurate conceptions of the form, surface, &c., of objects over which they rapidly pass their hands, as others could only derive from the long and painstaking examination of them by their tactile organs ; but they can discriminate minute differences, of which those who have not specially cultivated this faculty remain quite unconscious, even when their attention is pointedly directed to their discovery. The process by which the blind learn to read from books printed in an elevated type for their special use, affords an interesting illustration of the nature of the improveability of the proper sense of touch. On first making the attempt, the learner needs to use a large type ; and even although (to a person who has previously enjoyed his sight), the visual form of each letter may be well known, yet considerable experience is required for the ready recognition of the tactile form of each separate letter. After this step has been","page":1177},{"file":"p1178.txt","language":"en","ocr_en":"1178\tTOUCH.\ngained, the individual becomes able, by a further period of diligent application, to recognise the combination of letters in syllables and words, without forming a separate idea of each letter, just as we see to take place in the child learning to read by eyesight ; and the pupil in time acquires the power of reading line after line, by passing the point of the finger consecutively over each, with considerable rapidity. Now when this power has once been thoroughly acquired, it is found that the size of the type may be gradually diminished, so that at last it may be reduced to one but little larger than that of an ordinary folio Bible, which is read at least as rapidly as the words can be spoken* As an instance of the readiness and nicety of discrimination which is frequently acquired by those who are chiefly dependent upon this sense for their knowledge of the outward world, we may advert to the well-known case of Laura Bridgman ; who, though destitute of sight, hearing, and smell, is able to recognise individuals with whom she has once been well acquainted, by feeling their hands, even after a long distance of time. It is related of Carolan,the celebrated blind Irish bard, that on accidentally grasping, at an interval of some years, the hand of a female to whom he had been formerly attached, he at once exclaimed, with strong emotion, \u201c This is the hand of Bridget Cruise.\u201d A lady, who became blind, and soon afterwards deaf and dumb, in consequence of an attack of confluent small-pox, and whose case is recorded in the Annual Register for 1758, seems to have very speedily acquired a remarkable exaltation of the sensibility she retained. Like James Mitchell (see Smell, p. 702.), she could distinguish strangers from acquaintance by the smell ; but she required the further help of the touch to distinguish one friend from another. \u201c When they came in, they used to present their hands to her as a means for making themselves known. The form and the warmth of the hand generally furnished the differences which she distinguished ; but sometimes she would span the wrist and measure the fingers. A lady with whom she was well acquainted, coming in upon a very hot day after having walked a mile, presented her hand as usual ; she examined it longer than ordinary, and seemed to doubt to whom it belonged;\u2019but at length she said,\u2014 \u00ab I think it is Mrs. M. ; but she is warmer to-day than I ever felt her before.\u2019\u201d f\n* It is worthy of remark, that, when the idea of teaching the blind to read from raised characters was first being carried into practice, it was thought requisite by many to adopt a new alphabet of simpler forms, instead of the ordinary letters, in order that they might be more readily discriminated. This plan, however, was subject to the disadvantage that the teacher as well as the pupil was compelled to learn this new alphabet ; and as it was soon found that the ordinary Roman capitals, reduced to their simplest forms, could be discriminated by the blind with very little more trouble than the best set of new signs that could be devised, the idea of a special alphabet for their use has been given up.\nf \u201c Lost Senses,\u201d vol. ii. p. 81.\nOf this lady it is positively affirmed that she was able to distinguish colours by the touch. \u201c A lady, who was nearly related to the sufferer, having an apron on, which according to the fashion of the time, was embroidered with silk of different colours, asked her if she could tell her what colour it was ; and after applying her fingers attentively to the figures of the embroidery, she replied that it was red, blue, and green ; but whether there were other colours in the apron, the writer of the account does not remember. The same lady having a pink ribbon on her head, and being desirous still further to satisfy her curiosity and her doubts, asked her what colour that was ? After feeling it for some time, her cousin answered that it was a pink colour. This answer was the more surprising, as it showed that she was not only capable of distinguishing different colours, but different shades of the same colour.\u201d* It is probable that in this and similar cases, the difference of hue is indicated by some difference of surface, which becomes appreciable to a refined touch. Of course, it can only be to a person who has once enjoyed sight, and who can therefore form ideas of colour, that such ideas could be suggested by the sense of touch ; and a new set of associations must be formed by habit between the tactile qualities of the surface, and the visual conception called up by its designation. Those who have been born blind must be utterly incapable of forming any such conceptions, and distinctions of colour can be to them nothing more than names ; yet even such have been able to discriminate by the touch between stuffs of different hues, which were similar in other respects. That such a power should be attained seems the less difficult of belief, when it is borne in mind that all colour depends upon the molecular arrangement of the particles of the surfaces of bodies ; so that there is no great improbability \u2014 much less an impossibility\u2014 in the asserted discrimination of these by a touch rendered delicate by constant practice, and by the habit of attending to its minutest indications. It is well known that Dr. Saunderson, the celebrated blind professor of mathematics at Cambridge, not only acquired a very accurate knowledge of medals, but could even distinguish genuine medals from imitations, more certainly than most connoisseurs in full possession of their senses ; and this power must have depended on peculiarities of their surface, too minute to be appreciated by an ordinary touch, and not distinguished by the sight.\nNot only does the sense of touch, in its simplest form, undergo this remarkable exaltation, but also the muscular sense, which is employed in combination with it in the acquirement of information respecting the forms, dimensions, distances, &c. of objects. Of this, the case of the lady just cited affords an apt illustration : \u201c To amuse herself in the mournful solitude and darkness to which she had\n* Op. cit. p. 79.","page":1178},{"file":"p1179.txt","language":"en","ocr_en":"TOUCH.\n1179\nbeen reduced, the sufferer took to working with her needle ; and it is remarked that her needlework was uncommonly neat and exact. Among many other pieces of needlework preserved in her family, was a pincushion which could scarcely be equalled. She used also sometimes to write ; and her writing was executed with the same neatness and precision as her needlework ; the characters were very pretty, the lines were all even, and the letters placed at equal distances from each other : \u2014 but the most extraordinary circumstance was, that she could by some means discover where a letter or a word had been omitted, and would place the caret under and the word over, in the right place.\u201d * This fact is obviously analogous to those formerly related, in reference to the exaltation of the muscular sense in the state of somnambulism. (See Sleep, p. 694.) It is by the accurate estimates which they are thus enabled to form, that we find the blind able to learn various handicraft arts, performance on musical instruments, &c. &c., which they practice with great success ; cabinet-making, turning, and even watch-making, seem to be within the capacity of such as have a mechanical turn ; but the greatest perfection of this sense is shown by those who have succeeded in modelling and sculpture. Of these, Giovanni Goneili, sometimes called Gambasia, from the place of his birth, deserves special mention. He lost his sight at the age of twenty, and remained for ten years in that state, ignorant of the very elements of sculpture. But, on a sudden, the desire of making a statue came upon him ; and having handled in every way a marble figure representing Cosmo de Medici, he formed one of clay so extremely like, that it astonished all who saw it. His talent for statuary soon developed itself to such a degree, that the Grand Duke Ferdinand of Tuscany sent him to Rome to model a statue of Pope Urban VIII., which he also rendered a very striking likeness of the original. He afterwards executed many others with equal success ; amongst these, a marble statue of our Charles I. It is related that the Duke of Bracciano, who had seen him at work, doubted much that he was completely blind, \u2014 and in order to set the matter at rest, he caused the artist to model his head in a dark cellar. It proved a striking\n* Op. cit. p. 81. It is worthy of remark, that in consequence of the strangeness of these facts to those who observed them, it was long doubted Whether some faint remains of sight or hearing did not exist. Many experiments were tried to settle this matter ; but in this great caution was necessary ; for some of these being accidentally discovered, she fell into violent convulsions, \u2014 these being apparently induced by the mental agitation she experienced at the thought of being suspected of insincerity, or of being supposed capable of acting so wicked a part, as to feign such infirmities. Sir Hans SIoane, who attended this patient, long entertained doubts respecting the facts related of her; but having been permitted to satisfy himself by whatever experiments he thought proper, he at length declared his conviction that she was totally blind, deaf, and dumb.\nlikeness. Some, however, objecting that the duke\u2019s beard, which was of patriarchal amplitude, had made the operation of producing a seeming likeness too easy, the artist offered to model one of the duke\u2019s daughters, which he accordingly did ; and this also proved an admirable likeness. Dr. Guill\u00e9e, who details the preceding case in his \u201c Essai sur l\u2019Instruction des Aveugles,\u201d mentions also the more recent case of M. Buret, whom he calls \u201c one of the most able sculptors of the academy; \u201d who became blind at the age of twenty-five, but was not thereby deterred from pursuing with much success, the course of life which he had previously chosen. It is easy to be conceived that a blind man might thus model or chisel accurately under the guidance of his touch, so far as mere form is concerned ; but it has been thought difficult to understand how he could thus discriminate and embody that expression, which has been supposed to be intangible* When it is remembered, however, that expression must at last depend upon niceties of form, and can only be imitated by the sculptor who is under the guidance of his sight, by a minute attention to these niceties, the difficulty altogether disappears. The blind sculptor cannot form an idea of the expression of his model, as seen by the eyes of others; but he may reproduce that expression with complete success, by perfectly imitating the form which exhibits it ; just as he may study and understand the laws of optics, without having ever seen the faintest ray of light. The study of natural history might have been supposed to be beyond the reach of the blind, in consequence of the difficulty of distinguishing specimens by the touch alone ; yet there have been examples of complete success in this pursuit. Thus of John Gough it is related, that \u201c from an early age he showed a very decided taste for zoology ; and in time he began to enlarge his knowledge of organic bodies by extending his researches from the animal to the vegetable kingdom. To botanical pursuits all the time he could spare from the necessary studies of the school was most assiduously devoted ; and as his ardour in cultivating this branch of science was never relaxed, he soon conquered most of the difficulties which the want of sight opposed to the gratification of this taste, and was eventually able to discriminate and arrange with great accuracy the plants that came under his notice. His usual method of examining a plant was by applying the tip of his tongue to its several parts. Ordinary plants he could easily and readily distinguish by the touch of his fingers. To evince the power of discrimination and strength of memory, which could alone have enabled him to take an interest in this pursuit, it is mentioned, that towards the end of his life a rare plant was put into his hands, which he very soon called by its name, observing that he had never met with more than one specimen of it, and that was fifty\n* \u201c Lost Senses,\u201d vol. ii. p. 224.","page":1179},{"file":"p1180.txt","language":"en","ocr_en":"1180\tTOUCH.\nyears ago.\u201d* A case of the same kind has been long under the writer\u2019s observation ; the subject of it being a gentleman who became blind from amaurosis soon after the age of twenty. His attention having been directed to geology and conchology, he gradually acquired a very complete knowledge of shells both recent and fossil ; being not only able to recognise every one of the numerous specimens in his own cabinet, but also to mention the nearest alliances of a shell previously unknown to him. He has occupied himself, moreover, in freeing his fossil shells from their matrix, with a hammer and chisel, knife, &c. ; and has frequently done this with a perfection that could scarcely be surpassed, rarely injuring the specimen with his tools, and generally clearing it completely from its incrustation, where this was practicable. In this way he has succeeded in forming a very valuable collection of the fossils of the interesting locality in which he resides.\nA similar exaltation may manifest itself, under the like circumstances, in the general tactile sensibility, both of the surface and interior of the body, especially as affected by the vibrations transmitted through solid substances ; whereby a deficiency in the sense of hearing is in some degree supplied. Thus the visitor to a school for the deaf and dumb remarks with surprise that a slight rap given by the master on the table or floor is sufficient to excite the attention of the pupils ; and finds on examination that this is not heard, but is felt by them. A minute account of his personal experience on this head is given by Dr. Kitto ; and as it involves several interesting physiological considerations, the principal facts mentioned by him will be here brought under the notice of the reader. \u2014 \u201c In the state of entire deafness,\u201d he remarks, \u201c a peculiar susceptibility of the whole frame to tangible percussions supplies the only intimations which have the slightest- approximation to those which hearing affords. I was about to call this a peculiar susceptibility of the sense of touch ; but this would unduly limit a kind of vibration, which, in certain of its developments, seems to pervade the whole frame, to the very bones and marrow. I do not at all imagine that there is in this anything essentially different from that which is experienced by those who are in possession of their hearing ; but it would seem that the absence of that sense concentrates the attention more exclusively upon the sensation which is through this medium obtained; and the intimation of which, being no longer checked and verified by the information of higher organs, assume an importance which does not naturally belong to them.\u201d This sense of percussion is but little excited in the human body by the vibrations of air ; obviously because there is no expanded surface adapted to receive their influence. Thus Dr. Kitto mentions that the loudest thunder makes no impression upon him, unless it shakes\n* \u201c Lost Senses,\u201d vol. ii. p. 215.\nthe house in which he is ; in which case it communicates a sensation resembling that produced by the removal of a piece of furniture in an adjoining room.* In like manner, he is utterly unconscious alike of the sound of bells, and of the vibration produced by their percussion, unless the latter be propagated through solid bodies, as when he places himself in direct contact with a tower in which a powerful peal is being rung. \u201c I remember,\u201d he says, \u201c that once when I was showing a young friend from the country over St. Paul\u2019s, we happened to be up examining the great clock, at the very time it began to strike. The sensation which this occasioned was that of very heavy blows upon the fabric in which I stood, communicated to my feet by contact with the floor, and by the feet diffused over the whole body. So,\u201d he continues, \u201c guns \u2014 even powerful cannon \u2014 make no impression upon this sense, unless I happen to be very near when they are fired ; in that case, I can compare the effect to nothing better than the sensation produced by a heavy blow upon the head from a fist covered with a boxing glove. This effect could only be produced by the tangible percussion of the air, and by the percussion upon the ground transmitted by the feet.\u201d So, again, Dr. Kitto states that he is not conscious of even a very loud knock at the door of the room in which he is, unless the door be in such connection with the floor that the percussion is communicated through the latter, or unless he be himself in contact with some part of the wall to which it is hung. But, on the other hand, he states, \u2014 \u201c The drawing of furniture, as tables and sofas, over the floor above or below me, the shutting of doors, and the feet of children at play, distress me far more than the same causes would do if 1 were in actual possession of my hearing. By being to me unattended by any circumstances or preliminaries, they startle dreadfully ; and by the vibration being diffused from the feet over the whole body, they shake the whole nervous system, in a way which even long use has not enabled me to bear. The moving of a table is to me more than to the reader would be the combined noise and vibration of a mail coach drawn over a wooden floor ; the feet of children, like the tramp of horses upon the same floor ; and the shutting of a door like a thunder-clap, shaking the very house. It is by having once heard, that I am enabled to make such comparisons as these, for the illustration of a sensation which one who has never heard, and one who is not deaf, would be alike unable to describe.\u201d The fact that the shutting of a door is felt with painful distinctness (as Dr. Kitto elsewhere mentions), even when upon a different floor, whilst the loudest ordinary knocking at the same door is not perceived, very curiously\n* The writer of this article, residing near a railway tunnel, has frequently noticed that the emergence of a train is indicated by the succussion of the windows of his house, before it becomes audible.","page":1180},{"file":"p1181.txt","language":"en","ocr_en":"1181\nTOUCH.\nillustrates the necessity for the transmission of the vibrations along a solid medium. \u201cThe valve of the door on which the percussion is made by knocking, is a detached frame of wood hung upon hinges, and the vibration is therefore comparatively isolated and not propagated throughout the frame of the house, as is the case when, in shutting the door, the valve itself strikes the door-post, which is identified with the framework of the building.\u201d In illustration of the acuteness of this sense in his own person, Dr. Kitto states that the lightest footfall upon the same floor is quite sufficient to attract his attention, or even to arouse him from sleep. \u201c If any small article,\u201d he continues, \u201c such as a thimble, a pencil, a penknife, or even a more minute object, falls from the table to the floor, I am often aware of it, even when other persons sitting at the same table have not been apprised of it by the ear. The greater the number of my points of contact with the floor, the stronger are the impressions I receive : hence they are more vivid and distinct when I sit than when I stand ; because, in the former case, not only my own two legs, but the four legs of my chair, are concerned in conveying the percussion to my sensorium. And when the chair itself on which I am seated has been subject to the percussion, the sensation is such as baffles description. For instance, a few days since, when I was seated with the back of my chair facing a chiffoni\u00e8re, the door of this receptacle was opened by some one, and swung back so as to touch my chair. The touch could not but have been slight, but to me the concussion was dreadful, and almost made me scream with the surprise and pain, the sensation being very similar to that which a heavy person feels on touching the ground, when he has jumped from a higher place than he ought. Even this concussion, to me so violent and distressing, had not been noticed by any one in the room but myself. * * # If these perceptions are so acute in carpeted rooms, it will be easily understood by how much more intense they become upon a naked wooden floor. The sensation then amounts to torture \u2014 as every movement or concussion, in any part of the room, then comes with an intensity of effect, far more than proportioned to the difference in the impression which would, under the same circumstances, be produced upon the auditory sense.\u201d\nIt is interesting to remark that, notwithstanding this acuteness of the sense in question, it does not seem to convey (in Dr. K.\u2019s case at least) any information of the direction or distance of the percussions, except such as is afforded by their relative intensity. Thus he says ; \u2014 \u201cI am unable to determine from the information of the sensation itself, whether it has occurred upon the floor above, or in that below me, or in the passage or room adjoining that in which I may be at the time. I am not aware that the impression is more distinct from the floor above than from that\nbelow ; but it certainly is more distinct in another room of the same floor, than from either the one above or below ; whence I am much in the habit of referring to the next room the percussions which make the strongest impression on me. In this I am not seldom mistaken. # # # The information is equally defective, even in the very room I may happen to occupy. If a book or other object falls in any part of the room, the sensation is painfully distinct, the percussion being upon the very boards on which I stand ; but even in this case, 1 am at a loss for the quarter in which the circumstance has occurred, and generally look for it in the wrong direction, and have to scan the whole room with my eye before I can make it out.\u201d It is probable that the want of power to estimate direction arises from the circumstance that the communication of the percussions takes place, in this and similar cases, through the same channel (the floor) to the same parts of the solid mass of the body, through which the vibrations immediately spread in every direction. It can easily be conceived that if the percussions were transmitted through a liquid medium, its vibrations, being propagated in a more determinate direction, might affect one or another part of the surface in such a manner as to suggest the direction of their source ; and that in this mode aquatic animals endowed with a nervous apparatus at their surface, specially adapted to be impressed by such vibrations, might communicate with each other through great distances. This appears to be the case with regard to the Spermaceti Whale, and probably others of the Cetacea. It has been observed by the whale-fishers, that when a straggler from a \u201c school \u201d is attacked, even at a distance of several miles from it, a number of its fellows bear down to its assistance, in an almost incredibly short space of time. It can scarcely be doubted that this communication must be made through the medium of the vibrations of the water, excited by the struggles of the animal, or perhaps by some peculiar instinctive movements especially adapted for this purpose, and propagated through the liquid medium to the large cutaneous surface of the distant whales. And this idea is confirmed by the fact, that the nerves which proceed to the surface of the body pass through the layers of blubber (which form the inner part of the true skin) with scarcely any division, and then spread out into a network of extreme minuteness as soon as they approach the exterior of the integument. The expanse of such a network over a thick layer of elastic tissue, whose meshes are distended with oleaginous fluid, obviously affords a condition peculiarly favourable to the reception of impressions originating in percussion.\nAfter the details which have been given in proof of the degree of exaltation of which the general tactile sensibility is capable in the human subject, we shall have less difficulty in understanding that even the vibrations of air,","page":1181},{"file":"p1182.txt","language":"en","ocr_en":"1182\nTOUCH.\nexcited by percussion, may become the chief means of guidance to animals possessed of a special apparatus for taking cognisance of them. Such appears to be the case in the Bat tribe, and especially in those species whose habits are most exclusively nocturnal, and whose dwellings admit the smallest quantity of light. \u201c The whole surface of their wings, on both sides, may be considered as an enormously-expanded organ of touch, of the most exquisite sensibility to the peculiar sensation for which it is intended ; and it is, therefore, by the varied modifications of the impulsion of the atmosphere upon this surface, that the knowledge of the propinquity of foreign bodies is communicated.\u201d * It would not seem improbable, however, that the remarkable cutaneous expansions with which the nose and ear are furnished in many bats, are subservient to this function. The enormous extension of the external ear may doubtless augment the intensity of the sense of hearing ; but it is scarcely accordant with our knowledge of the conditions under which the sense of smell is exercised, to suppose that the extraordinary \u201c nose-leaf\u201d of the Bhinolophidoe should be in any great degree subservient to olfactive purposes. The bats of this group (to which belong the greater and lesser horseshoe bats of our own country) \u201c are more completely lucifugous and retired in their habits than any others ; they are found in the darkest penetralia of caverns, and other places where there is not even the imperfect light which the other genera of bats enjoy.\u201d f Some approach to this power of guidance, derived either from the impressions made by the air upon the cutaneous surface, or from the radiation of heat, is occasionally seen in blind persons; who can thus distinguish 1 by the hands, and even by the face, the proximity of solid bodies (as in approaching a wall, a door, or a piece of furniture) without actually touching them.\nThe sense of temperature, also, appears to be capable of considerable improvement, when its indications are habitually and discriminatingly attended to, or when the mind is intensely and exclusively fixed upon them. Thus it is related of Dr. Saunderson, that when some of his pupils were taking the sun\u2019s altitude, he was able to tell, by the slight alteration in the temperature of the air, when very light clouds were passing over the sun\u2019s disk.\nMorbid Conditions or the Sense of Touch.\nLike most other vital functions, the sense of touch may become disordered in the way of deficiency, excess, or depravation.\nThe state of complete deficiency is known as Anaesthesia; a term which, strictly speaking, designates the absence of all sensation, but which is more commonly employed as referring to the sense of touch alone. This\n* See Cheiroptera, vol. i. p. 599.\nf Loc. cit.\nstate, which may be either general or local, may arise from an interruption in the functional activity of any part of the nervous apparatus concerned in the reception of sensory impressions ; and thus may be due to causes acting either (1) at the peripheral origins of the sensory nerves, or (2) on the nerves in their course, or (3) on the sensorial centres ; as well as to such as act on the whole nervous system at once. The causes which act at the peripheral origins of the nerves may be such as affect either the nerves themselves, the capillary circulation, or both. Of the first we have a typical example in the \u201c anaesthetic agents,\u201d ether, chloroform, &c. ; the application of whose vapour for any length of time to the cutaneous surface, entirely suspends its power of receiving sensory impressions ; and that this results from the direct action of the substances on the peripheral nervous expansion, appears from the fact of the suspension being precisely limited to the part to which the vapour is applied. But anaesthesia may be induced, also, by the stagnation of the capillary circulation in a part, without any more direct affection of its nervous endowments ; as we see when the main artery of a limb has been tied, previously to the reestablishment of the supply of blood by the collateral circulation, or when the flow of blood through it has been impeded by temporary pressure. It is probable that cold operates in producing local anaesthesia in both these modes ; namely, by its direct sedative action upon the peripheral nerves ; and by the stagnation which it produces in the capillary circulation. That the local anaesthesia, which is a not unfrequent result of the presence of poisonous substances in the blood, is due to the special action of these substances upon the peripheral nerves of the particular locality, would not seem an improbable supposition ; when it is remembered how frequently poisons of various kinds single out some particular part of a structure apparently homogeneous, for the production of their peculiar effects, \u2014 lead, for example, in whatever way introduced into the system, acting first on the muscular fibres of the alimentary canal, and afterwards most commonly on the extensor muscles of the forearm, in which its presence has been detected by chemical analysis.\nOf the anaesthesia induced by causes acting upon the sensory nerves in their course from the periphery to the centre, our most frequent examples are those in which it is produced by pressure on these trunks, whereby the conveyance of the sensory impressions to the encephalon is effectually checked. Anaesthesia may also arise, however, from diseased conditions of these trunks, brought about by perverted nutrition ; and there is a form of paraplegia, in which the lesion of sensibility (which is more completely lost than the motor power) appears to commence in the peripheral expansions of the nerves, and to extend along the trunks to the central organs.* This is * Graves\u2019s Clinical Medicine, vol. i. p. 503.","page":1182},{"file":"p1183.txt","language":"en","ocr_en":"TOUCH.\nusually referrible, in the first place, to the influence of cold and damp ; and it is especially liable to occur in persons of a rheumatic or gouty diathesis. That even the sedative influence of cold may be propagated along the nerve-trunks, and that its anaesthetic effect is not due to its peripheral influence alone, appears from the circumstance remarked by Dr. Graves (loc. cit.), that the paralysis induced by handling snow, or by immersing the hands in freezing mixtures for some little time, is not confined to the hands and fingers, but extends to the muscles and surface of the fore-arms. And it was also remarked by the same eminent physician, that in a case in which the inside of the ring finger had been \u25a0wounded by a blunt needle, and a partial anaesthesia induced, the same effect was perceived in the little finger (alike supplied by the ulnar nerve), obviously through the extension of the paralysing influence towards the centre, so as to affect the trunk higher up than the point at which its branch to the little finger was given off. Dr. Graves further cites, as an example of anaesthesia having its seat in disordered nutrition of the peripheral nerves, and gradually advancing along their trunks towards the centres, the curious Epid\u00e9mie de Paris, which occurred in the spring and summer of 1828.\t\u201c It began (frequently in per-\nsons of good constitution) with sensations of pricking and severe pain in the integuments of the hands and feet, accompanied by so acute a degree of sensibility, that the patients could not bear these parts to be touched by the bed-clothes. After some time, a few days, or even a few hours, a diminution, or even abolition of sensation took place in the affected members ; they became incapable of distinguishing the shape, texture, or temperature of bodies, the power of motion declined, and finally they were observed to become altogether paralytic. The injury was not confined to the hands and feet alone, but, advancing with progressive pace, extended over the whole of both extremities. Persons lay in bed powerless and helpless, and continued in this state for weeks and months. Every remedy which the ingenuity of the French practitioners could suggest was tried, and proved ineffectual. In some, the stomach and bowels were deranged, and this affection terminated in a bad state of health, and even in death ; in others, the vital organs, cerebral, respiratory, and digestive, were in the same state as before their illness, and their appetites were good, but still they remained paralytics. At last, at some period of the disease, motion and sensation gradually returned, and a recovery generally took place, although, in some instances, the paralysis was very capricious, vanishing and again re-appearing. In the fatal cases, no evidence could be obtained, from the most diligent search, of any lesion, functional or organic, in the brain, cerebellum, or spinal marrow.\u201d* These phenomena are\n* Op. Cit. p. 504.\n1183\nscarcely explicable on any other hypothesis than that of some general cause (probably a morbrd matter circulating in the blood) affecting the nutrition and functional activity of the nerve-trunks, rather than of their centres.\nThat anaesthesia may proceed from various causes whose operation is limited to the sensorial centres, is a matter of every-day experience. It is, however, where they have suffered from some obvious lesion of a comparatively restricted character, that the proof of this is most complete ; for although there is strong ground for believing that the ordinary operation of anaesthetic agents and narcotic poisons is confined to the cerebrum and sensorium, yet we could not positively affirm such to be the case, since, when taken into the blood, they may act not only on the sensorial centres, but on the entire nervous system. All the phemomena of narcoctic poisoning, however, indicate that opium, alcohol, &c., single out the cerebrum and sensory ganglia for their special action, just as strychnia singles out the spinal cord ; the suspension of the functional activity of the former being usually complete, before there is the slightest affection of the latter. That a failure of the circulation in the encephalon produces complete and universal anaesthesia while it lasts, was fully proved by Sir A. Cooper\u2019s well-known experiment; and it seems probable that many of the structural lesions which manifest themselves in paralysis of motion and sensation produce this suspension of functional power in parts not themselves affected by disease, chiefly in virtue of the derangement of the intra-cranial circulation which they invole.\nThere is one of the phenomena of the anaesthesia produced by the accidental or intentional introduction of poisonous substances into the blood, which seems deserving of more special notice ; viz., the suspension of the power of receiving painful impressions, without the obliteration of the ordinary tactile sensibility. This is a frequent result of the exhibition of ether and chloroform ; and does net seem to depend upon a mere blunting of the ordinary sensibility. It has been especially noticed, also, in cases of lead poisoning, in which state it seems to be more frequent than complete anaesthesia. According to M. Beau, the insensibility to pain, which he terms analgesia, may be observed in a large proportion of cases of \u201csaturnine intoxication.\u201d \u201c We must not confine ourselves,\u201d he remarks, \u201c to asking the patient whether he feels, but limit our question to the sensation of pain. Parts which are thus insensible to pain are so also to tickling. This form of anaesthesia may affect the entire surface, being, however, most remarkable in the extremities, and especially the upper ones. It may extend even to the mucous membranes, and especially those which are normally endowed with great sensibility, \u2014 as the uvula, isthmus faucium, nares, or conjunctiva, \u2014 any of which parts may be tickled without the usual conse-","page":1183},{"file":"p1184.txt","language":"en","ocr_en":"1184\nTOUCH.\nquences, the patient still being quite conscious of the mere contact.\u201d *\nReference has been already made to the influence of the attention on the acuteness of sensations ; and to the slight degree in which they are felt, when the mind is completely engrossed in some other feeling or idea. This is sometimes seen in spontaneous reverie ; and there are individuals who can exert such a power of mental abstraction, as voluntarily to concentrate their attention on some external object, or internal idea, so as to escape all suffering from a severe operation. This, however, is much better seen in some of those cases of somnambulism (see Sleep) in which the mind is completely under the guidance of the suggestions received from without, its whole spontaneous directing power being suspended. For it is frequently possible, in such cases, to withdraw the patient\u2019s attention from any part of the body, to such an extent that the anaesthesia is complete as regards that part, whilst every other portion enjoys the ordinary sensibility. Thus a temporary loss of sensation on the whole ol one side may be induced, or a single limb may be rendered anaesthetic; and the sensibility of the parts may be instantaneously restored, merely by directing the patient\u2019s attention towards them.\nWith regard to hyper\u0153sthesia, or increased sensibility, we have much less definite information. There can be no doubt, however, that it, too, may proceed from changes either in the periphery, or in the central organs, and perhaps also from an alteration in the trunks of the nerves in their course. The acute sensibility of an inflamed or irritated part is an example of the first of these conditions ; and the extraordinary exaltation of sensibility in the incipient stage of phrenitis may serve as an illustration of the second. In some cases the entire nervous system would seem to partake of this undue excitability ; this we especially see in hysterical subjects, in whom the slightest contact frequently occasions intense suffering, so that even the mere pointing of a finger at any part of the body will cause a scream of alarm. The sufferings of such persons are not rightly designated as imaginary ; they are as real to them as are those proceeding from far more serious causes to persons of less excitable temperament. The fault partly lies in the habitual attention which they pay to the most trivial feelings ; but in part also, it may be surmised, to an abnormal state of nutrition of the entire nervous system,\u2014both centres and trunks,\u2014 from depravation of the blood. This view harmonizes well with the fact just now stated, that in the Epid\u00e9mie de Paris, a temporary hyper\u0153sthesia (afterwards giving place to an-\u00e6sthesia) was commonly among the earliest symptoms. And it is not a little curious that in the remarkable series of cases of leadpoisoning which recently occurred in the exroyal family of France, during their residence\n* Archives G\u00e9n\u00e9rales, tom. xvi. pp. 5\u201424.\nat Claremont, the same symptom presented itself, and was in some instances the only symptom which indicated the morbid contamination of the blood.* In most cases of this form of hyper\u0153sthesia, the exaltation of sensibility seems confined to the surface, being much more excited by a slight touch than by hard pressure; and this difference will frequently serve to distinguish the \u201c hysterical\u201d tenderness from that of inflammation, in which the pain is augmented the more severe the pressure. The writer has had opportunities of noticing an extreme sensitiveness to changes of temperature in certain cases of somnambulism, both natural and artificial ; and he believes that this fact affords a ready solution of various marvels which have been narrated touching the power of \u201cmesmerized\u201d subjects to distinguish a piece of money which had been held in the mes-merizer\u2019s hands, or a glass of water in which his finger had been immersed.\nIt has recently been proposed to apply Prof. Weber\u2019s method of estimating the relative acuteness of the tactile sense in different parts of the body, to the determination of the degree of anaesthesia or of hyper\u0153sthesia, in patients affected with these disorders. Thus it was found by M. Brown-S\u00e9quard that in one case of nearly complete anaesthesia of the lower extremities, the patient only felt a single impression on the skin of his legs, when the points of the compasses were from 10 to 20 centim. apart ; the normal \u201climit of confusion\u201d for this portion of the surface being from 3 to 5 centim. In another case of slighter anaesthesia, the \u201c limit of confusion\u201d in the same part was from 9 to 15 centim. And in a third case of very slight anaesthesia, it was from 6 to 7 centim. In a case of hyper\u0153sthesia, on the other hand, which accompanied paralysis of the motor power, the patient could perceive the distinctness of the two points on the foot, when they were separated to the distance of only 5 millim., although the normal \u201c limit of confusion\u201d in that part was from 25 to 30 millim. The sensibility to pain, in this case, was as much exaggerated as was the tactile sensibility.\nOf the depravation of tactile sensibility, manifested in a variety of morbid phenomena, \u2014such as the sense of heat or even of burning (without any real elevation of temperature), of formication, of tickling, of itching, &c., \u2014 it must suffice here to remark, that this, like the preceding affections, may be due to causes acting on the peripheral nerves, or on the nervous centres, or on the connecting trunks. Of the latter we have a good example in the formication which generally succeeds complete anaesthesia, when a nerve has been pressed upon for a time, and the pressure is then removed.\nW. B. Carpenter.\n* See Dr. Gueneau de Mussy\u2019s Cases of Poisoning by Lead at Claremont, in Dublin Quarterly Medical Journal, May, 1849.","page":1184},{"file":"p1185.txt","language":"en","ocr_en":"TUNICATA.\t1185\nTUNIC AT A. (Tuniciers, Fr. ; Nackt-Aluscheler and See-Scheiden, Germ.)\u2014The Tunicata are molluscous animals, having no calcified shell, but a more or less coriaceous envelope or tunic, whence their name. This external coat or test is either bag-shaped and provided with two apertures, or is tube-shaped and open at the ends. They have no distinct head, and no organs serving as arms or feet ; they are provided with a muscular and a nervous system ; and with well-defined organs of respiration, digestion, circulation, and generation.\nThey are exclusively marine, and are widely spread from the arctic to the tropical seas. Sessile or foot-stalked on the rock, or in-crusting seaweed and other bodies, their external form is seldom of graceful contour ; yet the arrangement of the individuals in the compound masses often exhibits curious and elegant designs. The floating forms, however, with their lengthened, sinuous chain, or tapering tubes, pellucid, rainbow-tinted, or, by night, brightly phosphorescent, are surpassed by no terrestrial object. The other, fixed, forms, not altogether destitute of elegance of colour in the northern seas, become in warmer climates more and more rich in variegated hues, and in the tropics are amongst the most resplendent living gems of ocean\u2019s parterres.\nThe earliest notice of the tunicate animals is made by Aristotle, who gives a very correct account of the anatomical and zoological characters of a simple Ascidian, which he calls Tf Qvov* * * \u00a7 They, however, attracted no further notice until comparatively late times. Rondelet f gives indifferent figures and descriptions. Gesner and Aldrovandus, uniting Rondelet\u2019s Teihya with those given by Belong, which are Alcyonia, were among the first who gave rise to the confusion that long existed in the history of these animals. Linn\u00e6us in the 4th edition of his Systema Natur\u00e6 placed a Tethyum in his system, under the appellation of Tethys ; he pointed out at the same time that the animal of bivalve Molluscs was a Tethys, showing that he was aware of the analogy of the Bivalves with the Tunicates. In other respects, however, he added to the confusion. After that Bohatsch \u00a7 and Plancus || figured and described some species. Baster1[ describes a species, and gives it the name of Ascidium (from acrico\u00e7, a skin-bottle), at the same time adding a very just remark on the analogy of its internal structure with that of the oyster. This analogy was noticed also by Pallas, who proposed the union of the Tethyum and Ascidium **, which Linn\u00e6us carried out in the 12th edit, of his Systema Natur\u00e6, uniting the species, noticed by Bohatsch and Koenig, under the\n* Hist. Anim. lib. iv. c. vi., and De Part. Anim.\nlib. vi. c. v.\nf De Piscibus, 1554.\tJ De Aquat. 1553.\n\u00a7 De quibusd. Anim. Marin. 1761.\n|| Conchis minus notis, pi. v. & vii. 1739.\nOpusc. subseciv. ii. x. 5. 1764.\n** Miscall. Zoolog. 74. 1767.\nVOL. IV.\nname of Ascidia, and confining the name Tethys to the inhabitants of the Bivalves.\nSubsequently, O.F. M\u00fcller*, O.Fabriciusf, Dicquemare j, Pallas \u00ff, and others, described and figured several Ascidiee, which Brugi\u00e8re || and Gmelinf collected together in their respective works, without adding much to the knowledge of the group. Cuvier\u2019s first observations on the simple Ascidians were begun in 1797, and his memoir on their anatomy was published in 1815.** About the same time were published the researches of Schalkf f on the anatomy, and of Cams jj on the anatomy and development of the Ascidians. The memoirs of P\u00e9ron and Lesueur$$ on the Pyrosoma, Desmarest and Lesueur || || on the Botryllus, and particularly the elaborate work of Savignyfl on the simple and compound Ascidians, enabled naturalists to make rapid advances in the knowledge of this family. With respect to the Salpians, Brown***, For-skahlj-f-'f, and Tilesiuswere the first to figure and describe any forms of this group. Considerable confusion with regard to these forms existed in the classifications of Linn\u00e6us, Pallas, Brugi\u00e8re, and Bose, and indeed in the earlier writings of Lamarck and Cuvier, until the latter had an opportunity of working out the anatomical characters of these animals.\nThe earlier works on the various branches of this subject have been succeeded by the publication of the researches of many distinguished naturalists. We are chiefly indebted to the labours of Cuvier, Savigny, Cams, MacLeay, and Van Beneden, for information on the structure and development of the simple Ascidians ; to the researches of Cuvier, Kuhl and Van Hasselt, Chamisso, Eschricht, and Krohn, for the history of the Salpians ; and to Lesueur, Desmarest, Savigny, Lister, Sars, Milne-Edwards, Audouin, and Forbes, for our knowledge of the compound ascidian forms.\nAnd, indeed, since the commencement of the present century, the organisation of this group has been studied with great care, rewarding the labours of naturalists with discoveries of the highest interest. \u201c It was in the animal of the Salpa,\u201d says Van Beneden, \u201cthat Van Hasselt discovered a heart of such extraordinary character, changing incessantly its auricle to ventricle and its ventricle to auricle, its ar-\n* Zool. Dan. Prodromus, 1766, f Fauna Groenland, 1780. j Journal de Physique, 1777.\n\u00a7 Spicilegia Zoologica, 1774, and Mem. de Pe-tersbourg.\n|| Encyclop\u00e9die M\u00e9thodique ; Vers Mollusques.\nSystema Natur\u00e6, edit. 13.\n** M\u00e9moires du Mus\u00e9um, tom. ii.\ntf De Ascidiarum Structura, Halle, 1814.\nU Meckel\u2019s Archiv, tom. ii. and Acta Cur. Nat. Bonn, vol. x.\n\u00a7\u00a7 Annales du Mus\u00e9um, tom. iv. fill Bull. Nouv. Soc. Philom. 1815,and Journal de Physique, tom. lxxx.\n<jr^[ M\u00e9m. Anim. sans Vert\u00e8bres, 2e part.\n*** Natural History of Jamaica, fff Descript. Animalium, &c. 1776.\n\u00dci Ann. Hist. Nat. Leipzig, 1802.\n4 G","page":1185},{"file":"p1186.txt","language":"en","ocr_en":"1186\nTUNICATA.\nteries to veins and its veins to arteries. The Ascidians, too, furnish the first examples of complete metamorphosis in the lower ranks of the animal kingdom. The honour of this discovery is due to MM. Audouin and Milne-Edwards. From the late discoveries of M. Sars, these metamorphoses increase in interest, and appear tobe still more remarkable. And, lastly, the Ascidians have contributed very considerably to our knowledge of the circulatory apparatus of the Mollusca generally.\u201d\nThe term Tunicata was first used by Lamarck ; its synonyms are Tethya, Auct. ; SoJ't-shelled Molluscs, Hunter ; les Ac\u00e9phales sans coquilles, Cuvier ; Acephalophora heterobran-cl\u00f9ata, Blainville ; Tunicaries, Kirby ; Gymna-cepkala, Bronn. The Class of animals to which it is applied may be zoologically defined as consisting of acephalous Molluscs ; with a soft shell or test, organised, coriaceous or gelatinous, frequently destitute of mineral constituents, having a large proportion of cellulose in its composition : animals single or aggregate ; the test of each animal provided with two apertures, one branchial, the other anal ; the mantle forming an interior coat ; the branchiae attached wholly or in part to the internal surface of the mantle ; the mouth, without labial tentacles, placed below the branchial apparatus ; animals hermaphrodite, undergoing metamorphosis in their young state.\nThe cavity, whether of single or compound Tunicates, is occupied by a more or less muscular sac, provided, like the external tunic, with tv/o orifices. This sac, identical with the \u201c mantle \u201d of the Acephalans, is attached to the inner surface of the test, generally only at the orifices, and contains the viscera. The digestive, reproductive, and circulatory organs are disposed at the base of the sac, and its upper and larger portion, lined with, or traversed by, the branchiae, forms the branchial cavity. This is placed at the commencement of the alimentary canal, of which it forms as it were the antechamber. The branchiae have generally the form of ridges, more or less complicated, and seldom symmetrical. The alimentary canal is simple, and barely distinguishable into gullet, stomach, and intestine. It is always convoluted or folded once on itself. The liver adheres to the stomach, and in many species is divided into distinct lobes. The\nheart consists of a slightly bent, contractile tube, and is situated near to or within the intestinal loop. The reproductive organs, consisting of ovary and testicle, are often lodged in the fold of the intestine.\nThe animal of these \u201csoft-shelled\u201d Molluscs has very close affinities with that of the other Acephalans, especially the lamellibran-chiates. And \u201c were the test of an Ascidian converted into a hard shell, symmetrically divided into two plates, connected together dorsally by cartilage, and capable of separation so as to expose the mantle along a ventral mesial line, whilst the orifices protruded at one extremity, it would present the closest similarity with many bivalve Molluscs.\u201d* (Forbes.)\nAll the Tunicata are free during the earlier periods of their existence ; some remain permanently free, floating in the water (Salpce, &c.), but the generality ( Botrylti, Ascidi\u0153, &c.) become fixed to shells, seaweeds, and other marine bodies. Some exist as distinct individuals (Ascidia, Cynthia, &c.), whilst various degrees of combination are affected by others (JBotryllus, Clavellina, Pyrosoma, &c.) ; and some are simple in one generation and combined in the next (Salpa).\nFrom the above-mentioned various conditions of individualism or aggregation under which these animals exist, the family is divisible into two groups \u2014 the simple and the aggregate. Such forms of the latter group as were known to the earlier naturalists were, from a general similarity of appearance, classed by them with Alcyonia. In the former group have been placed, until a late date, the numerous species of the Sal-pidce, which now however, like the above-mentioned groups, have been separately treated of and illustrated in memoirs and monographs devoted to them. Indeed, although the expressions, simple and aggregate, as will be seen hereafter, are very convenient in describing the physiology of the Tunicata, yet late researches have shown that the conditions to which they refer have but a subordinate value in reference to the natural grouping of the class.\nAs may naturally be inferred from what is stated above, the Tunicata have been subdivided in various manners. The arrangement we are inclined to adopt is as follows : \u2014\nDichitonida, Fleming.\nInner sac more or less detached from the external tunic ; united to it at the two orifices. Branchiae, large, equal, }> spread on the inner surface of this sac. Branchial orifice with an inner membranaceous ring and circle of tentacles.\nMonochitonida, Fleming.\nInner sac adhering throughout to the external tunic. Orifices\" without tentacular fringes.\nFixed. Branchial and anal 1 orifices not opposite to I each other. Branchiae [ conjoined.\nFloating. Branchial andl anal orifices opposite to I each other. Branchiae J disjoined.\nBranchial and anal orifices 1 opposite to each other. J Branchial and anal orifices 1 not opposite to each }-other.\tJ\nAscidiadae.\nClavellinid\u00e6.\nBotryllidae.\nPyrosomidae.\nSalpidae.\nPelonaiadae.\n* We may particularly mention the My\u0153, Pholades, &c.","page":1186},{"file":"p1187.txt","language":"en","ocr_en":"TUNICATA.\n1187\nDichitonida. \u2014Family Ascidiad\u00e6, E. Forbes. Synonyms: Tethyessimples, Savigny; Ascidid\u00e6, MacLeay ; Tuniciers libres ou Ascidiens, Lamarck; Ascidiaria, Stark; \u201c les Isol\u00e9es,\u201d Cuvier ; Ascidiacea, pars, Blain ville ; Ascidiens simples, Milne Edwards ; Ascidiens, Van Beneden.\nBody simple, fixed ; animals isolated or gregarious ; not united into groups by a common integument ; oviparous, not gemmipa-roiis. The following genera are members of this family : \u2014\nAscidiad\u00e6,\nvel\nAscidi\u00e6 simplices\nBranchi\u00e6 not plicated\nBranchi\u00e6 plicated -\nGenus Ascidia, Baster and Linnaeus. \u2014 \u201c Rarely,\u201d says Professor E. Forbes, \u201c is the dredge drawn up from any sea bed at all prolific in submarine creatures, without containing few or many irregularly shaped leathery bodies, fixed to sea-weed, rock, or shell, by one extremity or by one side, free at the other, and presenting two more or less prominent orifices, from which, on the slightest pressure, the sea-water is ejected with great force. On the sea shore, when the tide is out, we find similar bodies attached to the under surface of rough stones. They are variously, often splendidly, coloured ; but otherwise are unattractive, or even repulsive,\nAscidia mammillata. (Originalf.) a, branchial orifice, open ; b, anal orifice, closed.\nin aspect. These creatures are Ascidi\u00e6, properly so called. Numbers of them are often found clustering among tangles, like bunches of some strange semitransparent fruit.\u201d Some species (in France, vulg\u00f4 \u201c le vichet \u201d) on the\nf Sessile\nPedunculated\n_ f Ascidia.*\n( Molgula.\n{ Cynthia. Dendrodoa. Chelyosoma.\n{Bo tenia. Cystingia. Bipapi\u00fcaria.\ncoasts of the Channel f and the Mediterranean, and in the Chinese Seas, are valued as articles of food In this genus {fig. 766.) the body is sessile ; test, coriaceous or gelatinous ; branchial orifice eight and six-lobed ; branchial sac not plicated, surmounted by a circle of simple tentacular filaments.\nGenus Molgula, E. Forbes ; synonym, Ascidia, Auct. \u2014 Body more or less globular, attached or free \u00a3 ; test membranous, usually invested with extraneous matter ; orifices on very contractde and naked tubes, the branchial six-lobed, the anal four-lobed.\nGenus Cynthia, Savigny ; synonym, Ascidia, Auct.\u2014Body sessile, fixed or unattached; test coriaceous ; branchial and anal orifices opening in four rays or lobes ; branchial sac longitudinally plicated, surmounted by a circle of tentacular filaments.\nGenus Dendrodoa, MacLeay. \u2014 Body sub-cylindrical, fixed, sessile; test coriaceous, smooth ; orifices terminal, minute, indistinctly quadrifid ; branchial sac plicated ; tentacula\n* Some very good observations on the subdivisions of the Ascidi\u00e6 have been made by M. Savigny, Dr. Fleming, and Mr. MacLeay. * But we must not here enter further into details. The following classification is that adopted wholly or in part by the above authors respectively : \u2014\nj Pyrena.\nPhallusi\u00e6 - -< Phallusia.\n(_ Ciona.\nCynthia. C\u00e6sira.\nCynthi\u00e6 - -\u25a0*{ Styela.\nPandocia. Dendrodoa.\nf \u201cAt Cette,\u201d says Van Beneden, \u201cAscidi\u00e6 are taken regularly to market ; and Cynthia microscomus, although so repulsive externally, furnishes a very delicate morsel, much sought after by some.\u201d\n+ Individuals of several species of Ascidians, viz. of the following genera, Molgula, Cynthia, Cystingia, Bipapillaria, and Pelonaia, are found unattached. These animals, however, cannot be said to have an entirely free existence, their tests, whether pe-duncled or otherwise, being usually more or less imbedded in sand or mud, and frequently held to their anchorage by the agglutination of the surrounding sand-grains to their outer surface. But from such a position they are easily disturbed, unless when they are lodged within the mud-filled cavities of old shells and of water-worn stones, as is the case with the Pelonaia.\nAscidi\u00e6\n4 g 2","page":1187},{"file":"p1188.txt","language":"en","ocr_en":"1188\nTUNICATA.\nsimple (fig. 778). Dendrodoa closely agrees with Cynthia in its branchial reticulations and its digestive apparatus ; but, as Mr. Mac Leay has observed, of the two ovaries possessed by Cynthia, only one, and that the left, is found in Dendrodoa, whilst the right ovary alone is present in Pandocia.\nGenus Chelyosoma, Broderip and Sowerby. \u2014 Body depressed, oblong, fixed, sessile ; test coriaceous, its upper surface consisting of eight somewhat horny, angular plates ; orifices small, prominent, perforating the plated surface, each surrounded by six triangular valvules (fig. 767.) ; branchiae plicated ; tentacles simple.\nFig. 767.\nChelyosoma Macleayanum. (After Broderip and Sowerby.)\na, branchial orifice ; b, anal orifice ; c, coriaceous envelope of the sides ; d, stone to which the animal is fixed.\nTo the Ascidiad\u00e6 we may provisionally join the following obscure form, occurring on the coasts of South America :\nGenus Fodia, Bose. \u2014 Body oval, mammil-lated, divided throughout its length by a vertical partition, which contains the stomach, into two unequal tubes open at each end by an orifice, the superior aperture rather depressed and irregularly toothed, the inferior bordered by a circular collar forming a sucker, and serving to attach the animal to extraneous objects.\nGenus Boltenia, Savigny ; synonym, Ascidia, Auct. \u2014 Body more or less globular, fixed, pedunculated, attached sometimes to the stem of another individual; test coriaceous; orifices lateral, and each cleft into four rays ; branchial sac longitudinally plicated ; surmounted by a circle of compound tentacula.\nGenus Cystingia, MacLeay. \u2014 Body globular, fixed, pedunculated ; test subcoriaceous ; branchial orifice quadrifid, lateral ; anal irregular, terminal ; branchial sac plicated ; tentacula compound.\nGenus Bipapillaria, Lamarck. \u2014 Body more or less globular, free, pedunculated ; test membranous ; the extremity of the body opposite to the attachment of the peduncle bearing two equal, conical papillae, having their apices perforate ; each orifice furnished with three very short, stiff, setaceous, retractile tentacles.*\n* This obscure genus was established by Lamarck from a description and figure in P\u00e9ron\u2019s MSS.\nFamily Clavellinid\u00e6, E. Forbes. Synonyms : Ascidi\u0153, Auct. ; Tethyes simples, pars, Savigny ; Ascidiens sociales, Milne-Edwards ; P'erophoriens, Van Beneden.\nBody compound, fixed ; animals connected by creeping, tubular prolongations of the common tunic, through which the blood circulates. This family comprises two genera : \u2014 Genus Clavellina, Savigny ; synonym, Ascidia, Auct.\u2014Body elongated, erect, more or less pedunculated ; test smooth and transparent ; branchial and anal orifices without rays ; thorax usually marked with coloured lines (fig. 768.).\nFig. 768.\nClavellina producta. Group of two adult and several young individuals, magnified about five times.\n(After Milne-Edwards.')\nc, branchial orifice ; e, branchiae ; h, cloaca ; i, anal orifice ; k, inner tunic or mantle ; l, stomach ; m, intestine ; n, termination of the anus and oviduct in the cloaca ; o, the heart ; p, ovary ; p\", ova ready to pass into the cloaca ; u, u>, u\", reproductive buds, in different degrees of development, springing from the abdomen of the adults.\nGenus Perophora, Wiegmann.*\u2014Individuals pedunculated, suborbicular, compressed ; thorax not lineated by granular bands.\n* This curious little social Ascidian was first described and illustrated by Mr. J. Lister, in a paper \u201c On the Structure and Functions of tubular and cellular Polypi and of the Ascidi\u00e6,\u201d Philos. Trans. 1834. Lister gave no name to the animal,","page":1188},{"file":"p1189.txt","language":"en","ocr_en":"TUNICATA.\n1189\nFamily Botryllid\u00e6, MacLeay. Synonyms : Alcyonia, Auct. prior. ; T\u00e9thyes compos\u00e9es, Savigny ; les R\u00e9unis ou Botryllaires, Lamarck ; les Agr\u00e9g\u00e9s, Cuvier ; Ascidiacea, pars, Blainville; Ascidies compos\u00e9es, Milne-Edwards ; Polyascidiens, Van Beneden.\nBody compound, fixed ; animals associated; the tests fused together, forming a common mass in which the animals are imbedded in one or more groups or \u201csystems the individuals not connected by any internal union ; oviparous and gemmiparous.\n\u201c If, when walking on the sea-shore, about low-water mark,\u201d says the distinguished naturalist previously quoted, \u201c we turn over large stones, or look under projecting eaves of rock, we are almost sure to see translucent jelly-like masses of various hues of orange, purple, yellow, blue, grey, and green, sometimes nearly uniform in tint, sometimes beautifully variegated, and very frequently pencilled as if with stars of gorgeous device ; now encrusting the surface of the rock, now descending from it in icicle-like projections. These are compound Ascidians. A tangle or broad-leaved fucus, torn from its rocky bed, or gathered on the sand, where the waves have cast it after storms, will show us similar\n' Polyclinina\nBotryllid\u00e6,\nvel\t<\nAscidi\u00e6 composit\u00e6 Didemiiiiia\n^Botryllina\nThe tribe Polyclinina (les Polycliniens, Milne-Edwards) is characterised principally by the division of the body into three distinct portions, viz. a thorax, a superior abdomen, and a post-abdomen. It has, however, other anatomical peculiarities, such as the great development of the organs of generation, and the position of the heart at the inferior extremity of the body. This group comprehends numerous species, and is divisible into two natural sections, recognised by the external conformation of the anal orifice. In one division (P. bistellata) this orifice is surrounded with a regular circlet of rays or marginal lobules, and is exactly similar to the branchial orifice. In the other division (P. unisiellata) the anal differs from the branchial orifice in not being rayed, or at least in having merely irregular marginal lobules.\nGenus Sigillina, Savigny. \u2014 Common body a solid, elongated, erect cone ; gelatinous, pedunculated, isolated or attached to similar cones, consisting of a single system of many\nbut Professor Wiegmann subsequently (Jahresbericht in Archiv. 1835) gave it the appellation of Perophora Listen.\nbodies, mostly those star-figured, investing its stalks, winding among the intricacies of its roots, or clothing with a glairy coat the expanse of its foliated extremities. ... In examining these bodies, we find that it is not a single animal which lies before us, but a commonwealth of beings, bound together by common and vital ties. Each star is a family, each group of stars a community. Individuals are linked together in systems, systems combined into masses. .\t.\t. Indeed, few bo-\ndies among the forms of animal life exhibit such exquisite and kaleidoscopic figures as those which we see displayed in the combinations of the compound Ascidians.\u201d\nPrevious to the researches of Savigny, the Botryllid\u00e6 were regarded as Alcyonia ; Gaert-ner (1774) and Renieri (1793) being the only naturalists who had suspected their compound nature and true affinities.* \u201c The Memoir of Savigny, published in 1816, however, threw entirely new and unanticipated light on their nature. He showed that they were essentially Ascidians, differing from the simple forms only in being united into more or less complicated systems.\u201d f\nIn the arrangement of Professor Milne-Edwards the family is subdivided as follows :\nf Bistellata y Unistellata\nr Bistellata l Unistellata\nSigillina.\nPolyclinum.\nAplidium.\nSidnyum.\nSynoicum.\nAmaroucium.f\nDistomus\nDiazona.\nDidemnum.\n- Eucaelium.\n( Leptoclinum. f Botryllus.\n\\ Botrylloides.\nindividuals disposed one above another in irregular circles ; branchial and anal orifices each with six rays ; abdomen larger than thorax ; post-abdomen long and slender (fig. 769.).\nGenus Polyclinum, Savigny.\u2014Common body gelatinous or cartilaginous, polymorphous, sessile or slightly pedunculate ; systems numerous, convex, somewhat stellate, with central cloacal cavities; individuals (10 to 150) placed at very unequal distances from their common centre ; the cavity in the common tegument occupied by each animal is divided into three chambers one above another by contractions of its calibre ; abdomen much smaller than the thorax ; post-abdomen pedunculate.\nGenus Aplidium, Savigny ; synonym, Al-cyonium, Auct. \u2014 Common body gelatinous or cartilaginous, sessile ; systems very nume-\n* For the early history of this genus, consult the Memoir on Botryllus stellatus by MM. Desmarest andLesueur, Journal de Physique, tom. lxxx. 1815.\nf In the latest (\u201ccommemorative\u201d) edition of Cuvier\u2019s R\u00e8gne Animal, M. Milne-Edwards has established a new subgenus, Parascidia, which has eight marginal teeth on the buccal orifice.\n4 G 3","page":1189},{"file":"p1190.txt","language":"en","ocr_en":"1190\nTUNICATA. '\nroiis, slightly prominent, annular or subelliptical, without central cavities; the animals (3 to 25) are placed in a single row, at\nFig. 769.\nSigillina australis. (After Savigny.')\nA.\tVertical section of a cone, or \u201c system,\u201d showing the distribution o f the animals, magnified.\nB.\tIsolated individual, magnified.\nc. Natural size of isolated individual.\na, test, or external envelope ; b, branchial orifice ; c, anal orifice ; d, thorax ; e, abdomen ; f oesophagus ; g, stomach ; h, intestine ; j, thoracic sinus ; k, intestinal loop ; l, ovary ; m, oviduct.\nequal distances from their common centre ; branchial orifice six-rayed ; division of the thorax and abdomen not always distinctly marked.\nGenus Sidnyum, Savigny. \u2014 Common body gelatinous, presenting a series of closely grouped cones, truncated and starred at the summit,rising from a common incrusting base ; each cone composed of a fascicle of individuals, varying in number from five or six to ten or twelve, and forming a margin around a depressed centre. The animals partake of the characters of those of Synoicum and Aplidium, resembling the former in the structure of their stomach, and the latter in their branchial sac. Each has an eight-toothed branchial orifice and a simple tubular vent\nfolded against the thorax. The ovary is pe-duneled, and very conspicuous at the extremity of the animal. (Forbes.)\nGenus Synoicum, Phipps.*\u2014Common body semicartilaginous, cylindrical, pedunded, isolated or attached to similar cylindrical bodies; system single, circular, comprising six to nine animals, terminal; branchial orifice six-rayed; anal orifice having six very unequal rays, the three largest forming the exterior margin of the central star ; post-abdomen sessile.\nGenus Amaroucium, Milne-Edwards.\u2014Common body fleshy or coriaceous, polymorphous, subpedunculate or sessile, and incrusting ; systems numerous ; individuals arranged irregularly around common cloacal apertures ; divisions of the thorax and abdomina faintly marked. This genus resembles Aplidium and Synoicum in the general form of the animal, and Polyclinum in the presence of a central common cavity to each system (fig. 782 ).\nThe tribe Didcmnina (les Didemviens, Milne-Edwards) is formed of all the compound Ascidians whose body is distinctly divided into two parts, thorax and abdomen. These closely approach the Clavcllin\u0153, and are distinguished from the Polyclinina by the absence of the post-abdomen and by the position of the organs of generation and the hearr, which are raised up by the side of the intestine. This tribe, like the Polyclinina, is divided into two groups, according to the presence or absence of marginal rays around the anal orifice. M. Milne-Edwards observes that the bistellate group (Distomus and Diazona) forms a connecting link between the Clavellin\u00e6 and the Botryllid\u00e6.\nGenus Distomus, Gacrtnerf ; synonyms, Alcyonium, Auct., Polyzona, Fleming.\u2014 Common body semi-cartilaginous, polymorphous, sessile; s\\stems numerous, usually circular; individuals placed in one or two ranks at unequal distances from their common centre. Both orifices six-rayed.\nGenus Diazona, Savigny. \u2014 Common body gelatinous, orbicular, sessile or subpedunculate ; system single, expanded into a disc, comparable to that of a flower or of an Actinia; animals very prominent, arranged in concentric circles (fig. 770.) ; branchial and anal orifices six-rayed ; abdomen peduncled ; ovary enclosed in the intestinal loop.\nGenus Didemnum, Savigny.\u2014Common body coriaceous, polymorphous, sessile and incrusting ; systems numerous, compressed, without central cavities or distinct circumscription ; animals without any appreciable order of arrangement; abdomen peduncled; ovary placed by the side of the intestinal loop, increasing in length when the eggs are fully developed.\nGenus Euccdium, Savigny. Common body gelatinous, sessile and incrusting ; systems numerous, without central cavities or distinct\n* Voyage towards tlie North Pole, 1773, p. 199, pi. 13.\nf Gaertner, apud Pallas, Spicilegia Zoologica, 1774.","page":1190},{"file":"p1191.txt","language":"en","ocr_en":"TUNICATA.\n1191\nFig. 770.\nDiazona violacea, magnified. (After Savigny.)\ncircumscription ; animals sometimes scattered, sometimes arranged in a quincunx ; branchial orifice circular, without distinct rays ; anal orifice very minute and indistinct ; abdominal viscera pushed up by the side of the thorax.\nGenus Leptodinum, Milne-Edwards.\u2014Common body sometimes coriaceous, sometimes gelatinous, thin, sessile and incrusting ; systems few ; individuals arranged irregularly around common cloacal cavities ; abdomen peduneled, short, smaller than the thorax.\nThe tribe Botryllina (les Botry Miens, Milne-Edwards) comprises those compound Asci-dians that are united in systems around common excretory cavities or cloac\u00e6, and whose bodies are not divided into a distinct thorax and abdomen, the viscera being pushed forward on the side of the branchial cavity, and forming with the thorax an ovoid mass.\nGenus Botryllus, Gaertner ; synonyms, Al-cyonimn, Auct., Polycyclus, Lamarck. \u2014Common body gelatinous or cartilaginous, sessile and incrusting ; systems numerous, prominent, round or star-shaped, with central cavities; individuals, six to twenty in each system, lying horizontally with the vent far from the branchial orifice; branchial orifice simple (fig. 771.).\nGenus Botry/loides, Milne-Edwards. \u2014 This genus resembles the foregoing in most respects, except that the stars formed by the systems of animals are irregular and ramifying ; the cloac\u00e6 being prolonged into the common mass as irregular internal channels, on each side of which the individuals are placed in linear series, instead of having a simple star-like arrangement around the cloac\u00e6, as in Botryllus. The animals of Botry/loides, moreover, have a nearly vertical position, and their orifices are closely approximate (fig. 783.).\nWe should perhaps also refer to the group of the Botryllidce, an obscure form, first no-\nticed by Molina*, and subsequently named Pyura by Blainville, and considered by the latter to form a link between the simple and compound Ascidians. M. Blainville gives the following characteristics.\nBotryllus violaceus. Two of the star-like systems, magnified. (After Milne-Edwards.)\na, a, common test ; b, b, b, some of the branchial orifices ; c, the common anal orifice of one of the systems.\nGenus Pyura, Blainville.\u2014A pyriform body, with two small short tubes, occupying a cell in the external envelope, and forming, by its union with 10 to 12 individuals, a kind of polymorphous mass somewhat resembling honeycomb, apparently without any external orifice.\n* Saggio sulla Historia naturale del Chili. Bologna, 1782, 4to.\n4 g 4","page":1191},{"file":"p1192.txt","language":"en","ocr_en":"1192\nTUNICATA.\nFamily Pyrosomid\u00e6. Synonyms : Lucies compos\u00e9es, Savigny ; Tuniciers r\u00e9unis, pars, Lamarck ; \u201c les agr\u00e9g\u00e9s,\u201d pars, Cuvier ; Sal-piens agr\u00e9g\u00e9s, Blainville ; Lucidce, MacLeay; Pyrosomiens, Milne-Edwards and Van Bene-den. ThePyrosomians are represented by three or four species of the single genus Pyrosoma.\nThey inhabit the Mediterranean and the warmer parts of the ocean ; in the former at times their abundance is a source of dread to the fishermen, sometimes even completely clogging their nets ; and in certain oceanic regions they are met with in almost incredible profusion. Their delicate and transparent forms, their elegant tints, and their unrivalled phosphorescence render them the most beautiful of Molluscs, and objects of admiration to the naturalist and the voyager. Mr. Bennett relates that, during a voyage to India, the ship, proceeding at a rapid rate, continued during an entire night to pass through distinct but extensive fields of these Molluscs, floating, and glowing as they floated, on all sides of her course. Enveloped in a flame of bright phosphorescent light, and gleaming with a greenish lustre, the Pyrosomes, seen at night, in vast shoals upwards of a mile in breadth, and stretching out till lost in the distance, present a spectacle the glory of which may be easily imagined. The vessel, as it cleaves the gleaming mass, throws up strong flashes of light, as if ploughing through liquid fire, which illuminates the hull, the sails, and the ropes with a strange unearthly radiance.\nGenus Pyrosoma, P\u00e9ron. \u2014 Common body semi-cartilaginous, floating, cylindrical, 2 to 14 inches long, \\ to 3 inches in circumference ; bearing externally numerous pointed processes, hollow and mammillated within, and open at one of its extremities only. Animals associated in a verticillate arrangement, having two orifices, one at each extremity ; elongated, fusiform, tapering at the outer, and obtuse at the inner extremity ; united at the circumference of the middle portion, by the fusion of the tests to one another into rings, more or less regular, and varying in number according to species, so that the whole forms the long cylinder above described.\nMonochitonida. \u2014 Family Salpid\u00e6, Forbes. Synonyms : Salpce, Auct. ; Thalides, pars, and Lucies simples, Savigny; Biphores, Brugi\u00e8re ; Biphoridce, MacLeay; Tuniciers libres, pars, Lamarck ; \u201c les isol\u00e9es,\u201d pars, Cuvier; Salpacea, pars, and Salpiens simples, Blainville ; Salpiens, Van Beneden. The Salpians are free, swimming in the ocean ; plentiful in the Mediterranean and the warm parts of the ocean ; occurring also occasionally in the Norwegian and North British seas. In shape they resemble a short and wide tube, sometimes oval or cylindrical, sometimes more or less square in its transverse section, and varying considerably in size according to species, from half an inch to 8 or 10 inches in length.\nThe test is thin and transparent, open at the ends and often supplied with terminal and lateral processes. The mantle lines the test, and is more or less adherent throughout ; its\ninterior constitutes the branchial cavity ; it is provided at one of the terminal openings with a more or less perfect valvular apparatus; and contains a branchial fold traversing it obliquely. Near one extremity the chief viscera are grouped together into a conspicuous mass , (the \u201c visceral nucleus\u201d of authors), to which _ the brilliant tints of the liver usually impart an orange, brown, or reddish hue {fig. 772.).\nFig. 772.\nSalpce, isolated and associated.\nA. $. runcinata, solitary; B. S. runcinata, associated ; c. S. zonaria, aggregated.\nThis family is of considerable interest on account of their singular mode of reproduction, discovered by Chamisso, and on account of the philosophical generalisations partly founded thereon by Steenstrup. These animals occur under two distinct conditions, being at one time solitary, and at another associated into circular or lengthened groups \u2014 termed garlands, cordons, ribands, and chains (fig. 772. B and c). The Salpa-chains, varying in length from a few inches to many feet, swim through the tranquil water with a regular serpentine movement, and are often regarded by sailors as sea-serpents ; but when taken from the water the individuals of the group are easily detached. Thus, in consequence of accidents, separate members of these chains are often met with in seas abounding with these Molluscs ; but other, separate, Salpce are also met with that have never been united to others, and differ considerably in form from the associated ones (fig. 772. a).\nChamisso, however, discovered that such permanently solitary Salpce do not belong to species distinct from those united in chains, however dissimilar (and they are usually so dissimilar as to appear even generically distinct), but are either the parents or the progeny, as the case may be, of the aggregate forms ; and that chained Salpce do not produce chained Salpce, but solitary Salpce, which in their turn do not produce solitary, but chained Salpce. Consequently, as Chamisso graphically observed, \u201ca Salpa-mother is not like its daughter or its own mother, but resembles its sister, its grand-daughter, and its grandmother.\u201d*\nThis family is mainly represented by the * Forbes, British Molluscs, p. 48.","page":1192},{"file":"p1193.txt","language":"en","ocr_en":"TUNICATA.\ngenus Salpa, Forskahl ; synonyms Thalia, Brown ; Holothuria, Linn\u00e9 and Pallas ; Dagysa, Banks and Solander ; Biphora, Brugi\u00e8re ; Tethis, Tilesius ; Pegea and Iasis, Savigny. The characteristic features of this genus are detailed above.\nQuoy and Gaimard * established for some animals nearly allied to the Salpes and inhabiting the coasts of Amboina, the genus Do-liolium, the characters of which are, its having the form of a little cask open at the ends; from two to ten lines in length ; the anterior extremity a little prominent ; marked with circles in relief on the external surface ; and having internal branchia, divided into two branches ; and a heart and a dorsal vessel, situated near the union of these branches. This name had also been previously given by Otto f to a genus established by him on a Mediterranean Salpa, mutilated by a crustacean of the genus Phronyme, that had made it its habitation. This form, like Salpa triangularis and S. polymorpha (by Quoy and Gaimard, and Bory de Vincent), has been erroneously regarded as belonging to the family of Biphydes. MM. L\u00f6wig and K\u00f6lliker, however, who found the tissue of Boliolium to be identical with the peculiar substance of the test of other Tunicata, have pointed out its true affinities, and placed it with the Salpid\u0153.\nFamily Pelonaiad\u00e6, Forbes.\u2014- This family is represented by two rare animals, both inhabitants of the Scottish seas, constituting two species of a single genus, Pelonaia, established by Professor E. Forbes and Professor Goodsir.J We have derived our description of the general and anatomical characters of these interesting Molluscs from the detailed account given of them by the original discoverers.\nGenus Pelonaia, Forbes and Goodsir. \u2014 Animal simple, unattached. Test more or less cartilaginous, smooth or wrinkled, elongated, and cylindrical ; anterior extremity bearing two orifices, four-cleft, without tentacles, and placed on the same plane, on two equal, approximate, papillose eminences ; posterior extremity ending in a blunt point ; mantle adherent to the test. The Pelonai\u0153 live buried in mud, quite unattached to any other body, and are extremely apathetic animals, presenting scarcely any appearance of motion.\nAnatomy and Physiology of the Tunicata.\nIt w'ill be most convenient to describe the test generally for the whole tunicate class, and the rest of their anatomy under the heading of each of the families.\nTest or Shell. \u2014 The test or external envelope of the Ascidiad\u0153 is subject to considerable variation of shape ; from the bottle-like form of the Ascidiu {fig. 766.), to the flat, patellalike form of Chelyosoma {fig.767.) ; it is elastic,\n* Voyage de l\u2019Astrolabe, Zoologie, tom. iii.\nf Nova Acta Academ. Nat. Curios, t. xi.\nJ Jameson\u2019s Edinb. New Philosoph. Journal, vol. xxxi. 1841.\nvarying very much in its thickness and consistence in different species. In colour it varies considerably, being occasionally nearly black, sometimes red, orange, yellow', or milky white. Its surface is sometimes smooth, often tuberculated, covered with hairs or spines, or otherwise roughened. Sometimes minute patches of horny tissue or hardened epidermis rise up irregularly on the surface ot the test ; in other cases these are placed in a tessellated arrangement. In the peculiar and unique form, Chelyosoma, first noticed by Messrs. Broderip and Sowerby, and since more fully described by Professor Eschricht, the upper surface of the test is occupied by eight large, horny, polygonal plates arranged somewhat like the shell-plates of a tortoise, and by several smaller triangular plates, which form two circles, one around the branchial, and the other round the anal aperture of the animal {fig. 767.). The large plates are so disposed that the branchial orifice is surrounded by three plates, and the anal by four, besides that which is intermediate and abuts upon both : this latter plate is hexagonal, the sides in contact with the orificial valvules are lunated. The three plates near the branchial orifice are much larger than the four which are near to the anal orifice. Each of the plates is marked with three or four elevated stri\u00e6, which are near to the edges of the plate, and parallel with them, leaving an area in the centre, and giving rise to a general resemblance to the external plates of the shell of a land tortoise. The orifices are very small, and are surrounded by six triangular valvules, each transversely striated, and, when shut, rising from the surrounding surface in the form of a cone. The lower or adherent part of the test of Chelyosoma is coriaceous, with occasional slight traces of separation into plates.\nThe test of Ascidice is frequently covered with innumerable smaller animals and their spawn. Modiol\u00e6 and Annelids burrow in it ; Cirrhipeds, naked Molluscs, and Actiniae lodge upon it ; and Corallines cover it sometimes with a little forest ; a condition fully justifying the denomination of \u201c microcosmus,\u201d bestowed by Redi * on a Mediterranean species. Occasionally, as in Ascidia conchilega and Mol-gula oculata, the animal works up extraneous matter, as gravel, fragmentary shells, &c., with the external surface of the test. It is by this shell or test that the animal fixes itself. In the sessile species, the tissue of the base or the side of the test interlaces with the stems of sea weeds and corallines, or closely adheres to the surface of another ascidian sac, or of a stone, a shell, a crab, or other object. . In the peduncled forms this tunic is at one point prolonged into a tubular process or stem, the distal extremity of which is attached to marine bodies in the same manner as the base of the sessile tests. In Cystingia and Bipapillaria, however, this process or stalk appears to be less perfectly developed, and not to be al-\n* Opuscula vai\u2019ia Physiologica, 3 vols. 12mo. Lugd. Batav. 1725.","page":1193},{"file":"p1194.txt","language":"en","ocr_en":"1194\nTUN 1C AT A.\ntogether adapted to maintain a permanent attachment to a fixed body.\nThe external envelope of the Ascidiad\u0153 is always perforated by the two apertures characteristic of the Tunicata, and analogous to the prolonged respiratory orifices of the Cardiace\u0153 and other Acephala. One of these apertures *, nearly always placed at the summit of the test, receives the sea-water, and admits it into the branchial cavity. The second aperture j- is placed a little lower than the first, and is in communication with the rectum and oviduct. In Boltenia the orifices are lateral ; in Cystingia the branchial orifice is lateral, and the anal terminal ; the oral orifice being always the highest in relative position, and nearest to the insertion of the pedicle by which the animal is suspended. In Chclyosoma and Dendrodoa the orifices are placed on the same plane ; in the former, on the nearly flat superior surface of the animal, and in the latter they are terminal.\nThe edges of the orifices are more or less crenulate or divided. The branchial orifice is 8-9 rayed, and the anal 6 rayed, in Phal-/usia ; both orifices are 4-fid in Cynthia, Bol-t\u00e9nia, and Dendrodoa. When contracted, they are thrown into longitudinal folds ; this is the more observable when the orifices are somewhat prolonged into tubes.\nThe test receives from the body bloodvessels, which its semitransparency in some species allows the eye to follow to the extreme ramifications. In the thinner tests the vessels are but few, and sometimes altogether escape observation; but in the thick pellucid test of Ascidia mammillata the eye can discern an extensive network of vascular ramifications. The bloodvessels enter the test near the base. The internal surface of the test has often a glistening and pearly appearance, anti is always lined with an epithelium. In Boltenia reni-formis this is a loose tissue, and forms a slight attachment to the external surface of the muscular sac or mantle of the body.\nIn A. mammillata a thin vertical septum traverses a part of the cavity of the test.\nThe test of the Clavellinid\u0153 is very similar in consistence and general appearance to that of some of the more delicate species of the Ascidiad\u0153, but differs materially in having tubular prolongations running from its base, which are traversed by vessels continuous from one individual to another, and from which root-like processes young individuals are continually being produced by the process of gemmiparous reproduction {fig. 768.).\nThe tube-like test of the Salpid\u0153 is \u201csemiear-tilaginous, or gelatinous, seeming as if carved in crystal,\u201d its transparency rendering conspicuous the brilliant hues of the liver of the contained animal. It is usually more or less angular, bearing elongated crests, denticles, and other processes, by means of which the cohesion of the aggregated individuals is maintained {fig. 772.).\n* The first, oral, buccal, branchial, or respiratory.\nf The second, anal, ventral, or the funnel.\nThe tests of the little animals of which the cylindrical body of the Pyrosoma is composed, are intimately connected by their lateral surfaces, leaving their terminal orifices free {fig-186. a). The tissue of the whole common envelope is semicartilaginous, transparent, tinted with azure and other colours.\nIn the Botryllid\u0153 the external tunic is represented by the tegumentary tissue common to the whole association of animals, and which may perhaps be compared to the polypary of aggregated Polyps. The close aggregation of the animals causes a fusion, as it were, of the tests of the whole into a coriaceous or gelatinous mass, coated with a tough epidermic membrane, and more or less regularly beset with individuals or groups of individuals (systems) ; or, rather, the soft test of the originally isolated individual, or single system, increasing in bulk and producing within itself more and more embryos of individuals and systems, becomes an extended, homogeneous mass, in which numerous individuals are lodged {fig. 771.). This mass is irregular, fungous, jell)-like, spongy, or coriaceous, incrusting other sessile Tuni-cates and a variety of marine bodies.\nStructure and chemical composition of the test. \u2014We are indebted to the labours of MM. L\u00f6-wig and K\u00f6lliker* for considerable information on the subject of the constituent elements and the growth of the test of the simple and the compound Ascidians. These researches were undertaken with the view of examining into Dr. Schmidt\u2019s statement of the existence of the vegetable element \u201c cellulose\u201d in the tissue of the ascidian envelope. This they found to be correct (as the following statements will show), and they have also offered a lucid explanation of the fact, to which we shall subsequently refer. Cellulose forms the cell walls of vegetables, and is unaffected either by soda or hydrochloric acid.\nThe cartilaginous envelope of Phallusia manimillaris (Fam. Ascidiad\u0153), examined in specimens preserved in spirit, is composed of three layers of different thicknesses (fig.113.). The internal layer, formed simply of polygonal, nucleated, epithelial cells, measuring 0'005//', covers all the interior surface of the test; at the two external orifices, and at the points where it receives the nutrient vessels of the test, it is united with another epithelial tissue covering the mantle. The second layer is considerably thicker, and is composed of a homogeneous substance, containing crystals and nuclei. The former are not present everywhere, and are, perhaps, quite absent in the recent animals ; when present they are visible to the naked eye, and appear like white stri\u00e6 ; seen under a moderately magnifying power, they have the form of crystals united in the form of a star, or of irregular and polymorphous concretions. The nuclei are present in considerable numbers and under different forms ; those situated towards the interior are round, O-OOI\u00d4'\"\u20140002\"', with one or two\n* Annalesdes Sciences Naturelles, 3 ser. tom. vi. 1846.","page":1194},{"file":"p1195.txt","language":"en","ocr_en":"TUNIC AT A.\t1195\nopaque nucleoli, similar to fat-granules. The external nuclei are larger, round or more or less produced, and contain clear or granular substance, and usually some opaque granules.\nFig. 773.\nTest of Phallusia mamviillaris.\nA. Transverse section, magnified 30 times. 1, internal layer of epithelial cells ; 2, the second or intermediate layer, consisting of a homogeneous mass, thickly strewn with nuclei ; 3, the external layer, composed of a fundamental mass and cells of cellulose, with dispersed nuclei (c), and having pigment-cells and acicular crystals in the upper part; 4, vessels.\nb. A portion of the same, magnified 350 times, a, fundamental mass ; b, cellulose cells ; c, nuclei, some round, others star-shaped; d, acicular crystals of carbonate of lime ; e, the extremity of a vessel ; /, pigment-cells.\nThe third layer forms the principal mass of the test of this species. It is the seat of the numerous and large arteries, which, arising from the heart, traverse it in every direction, having brush-like ramifications, that penetrate almost to the exterior surface, and then appear to pass into other vessels that accompany them in their course. This layer is formed of large cells, besides a clear homogeneous substance, which is a continuation of the principal substance of the second layer; besides these there are locally distributed crystals, nuclei, and pigment-cells.\nThe large cells, which R. Wagner previously thought to be cartilaginous, are of a peculiar nature, and resemble no other animal cell hitherto known, except perhaps those of the chorda dorsalis of some animals. The most remarkable character of these cells is their size, which varies from O'OOS\" to 0-05'\", the average being 0*02//r to O'OS\"'. Their form is spherical, pyriform, or elliptical ; their contents diaphanous and quite destitute of nucleus or granules : and their membrane delicate, smooth, and of an equal thickness throughout.\nThe smallest cells are irregularly dispersed in the homogeneous fundamental mass that is common to the second and third layers. The larger cells are arranged closely together towards the exterior surface of the layer, presenting a very regular cellular tissue with very little intermediate substance; but, immediately beneath the external surface of the envelope, the cells are rather more distant one from another, and the intermediate tissue more\nvisible. The crystals and pigment-cells before mentioned, are present only in the outer part of this third layer ; the former are acicular, about 0,0015/// in length, occupying in compact masses the intercellular intervals ; the latter are yellow, and filled with somewhat large granules, and surround in particular the extreme ramifications of the vessels. The nuclei, lastly, are similar to the large nuclei of the second or intermediate layer, and are everywhere present between the large cells in considerable numbers.\nWhen slices of the test are treated with hydrochloric acid, the crystals of the second and third layers quickly disappear; treated with a solution of soda, the epithelial ceils, the nuclei, the pigment-cells, and the vessels are dissolved. The fundamental homogeneous substance of the second and third layers and the large cells are not dissolved, nor do they suffer any modification.\nIn Phallusia monachus the large cells measure from 0\u201901/// to 0-02//', and are more distinctly separated from one another than in the preceding example. The nuclei of the homogeneous substance are few, and generally fusiform or even ramified ; at the external surface of the envelope they are mixed up with a great number of minute yellow pigment-cells and pigmentary granules, as well as with acicular crystals and very minute crystalline concretions ; all of these being in the greatest numbers in the neighbourhood of the extremities of the vessels. In one specimen of this species MM. L\u00f6wig and K\u00f6lliker observed, that in the interior of the third layer no cells could be distinguished ; ultimately, however, they distinctly saw well defined cavities or lacunae, which were evidently vestiges of cells that had been more or less completely fused with the intermediate homogeneous substance ; and the traces of these lost cells were found to be more and more distinct towards the band of perfect cells in the surface of the test.\nIn Phallusia sulcata the large round or elliptical cells, without nuclei, have a diameter of 0-01'\"\u20140-15'\".\nIn Phallusia gelatinosa a very peculiar formation was observed by the experimenters. In one specimen the soft, gelatinous substance of the envelope exhibited no trace of cells throughout its thickness, but its mass was principally composed of a homogeneous substance similar to that of the other Ascidies. In another individual they observed some few and indefinite remains of cells. In both specimens they found, as in the other species, vessels and nuclei, the latter for the most part round and measuring 0,002///, in the homogeneous substance. In the individual destitute of cells, there was also in the exterior part a very large quantity of acicular crystals and yellow granules, the latter frequently resembling the nuclei with large coloured nucleoli. The tissue in all the Asddi\u00e6 examined, when chemically treated, behaved in a similar manner to that of Phallusia mammillaris.\nWe have observed that the test of Boltenia rcniformis (preserved in spirit) presents a ho-","page":1195},{"file":"p1196.txt","language":"en","ocr_en":"1196\tTUNICATA.\nmogeneous structure crowded with \u201c nuclei \u201d and bloodvessels, and only occasionally does any trace of cellular tissue present itself, in which case the cells are very minute, polygonal, and compressed. Mr. J. Quekett has detected calcareous spicul\u00e6 in the test of this species. They are situated towards the exterior, and are very numerous and excessively minute. Their form is usually cylindrical, with triradiate or 4-5-fid extremities.*\nThe composition of the test of Clavellina lepadiformis corresponds in all respects to that of the above mentioned Ascidi\u00e6 ; certain parts in the same individual having a more particular resemblance to one species, and others to another. The test, however, is quite destitute of bloodvessels. Transverse sections of the stalk of the Clavellina and of the excrescences that spring from it, exhibit a tissue composed of round or elongated non-nucleated cells, 0*01///\u20140*0W\", almost destitute of intermediate tissue, and arranged very close to one another.\nIt is only towards the upper extremity of the stalk that the cells become more and more separate, and even disappear little by little, as happens in some Ascidice, and give place to an intermediate homogeneous substance, bearing a quantity of nuclei. In the largest and superior moiety of the test a peculiar structure is found. Externally is a dense, but not thick, layer of delicate cells, which are very difficult to recognise, and measure about 0-0*2///. Between the cells, and immediately at the surface, are crystals of carbonate of lime, scattered nuclei (measuring 0\u2019002\"'), and large round fatty granules. Interiorly to this occurs a still thinner lamina, composed of a transparent, colourless, homogeneous substance, with infinitely minute pale granules. Next, there is a layer of round granules or vesicles. These are spherical, measuring O'OOO\u00f4'\", O10004\"'', and even 0 005'\"; their surface is smooth or granulated; the largest are placed in the middle, the smallest at the exterior; they appear opaque, and like starch or fat granules. With solution of iodine, they become yellowish, without presenting any trace of blue, and are probably fat grains.\nSucceeding to these, a thick layer presents itself, homogeneous, diaphanous, with some few minute spherical nuclei, which, the nearer they approach towards the interior, contain more and more colourless granules. Lastly, quite at the interior surface, is a thinnish, completely diaphanous substance, of equal thickness throughout, with spherical granular nuclei, measuring about 0'003///.\nTreated with soda and with hydrochloric acid, the crystals, nuclei, and fat granules of the test of the Clavellina disappear ; the large cells, on the contrary, and the homogeneous substance, with its scattered granules, remain perfectly unaffected, proving the identity of the chemical composition in Ascidia and Clavellina.\n* Several specimens are figured by Mr. Quekett in the Descript, and Illustr. Catal. of the Histological Series in the Mus. Royal Coll. Surgeons, 1849, plate xvii. fig. 13.\nThe Salpa maxima does not contain, in its gelatinous envelope, any trace of cells similar to those of the Phallusia and Clavellina. It is for the most part composed of a homogeneous, clear, diaphanous substance. Towards the interior surface, the several elements are not so clearly arranged as in the middle and external layers. In the innermost layers, a multitude of very minute granules are present; in the others there are little round nuclei, nucleated cells, and spherical or starshaped crystalline concretions. These latter are very regular, and formed of 3\u20147 straight rays, springing from a centre (fig. 774. c). They\nFig. 774.\nA. Incrusted cells of the fundamental mass of Didemnum candidum. a, unaltered cells ; b, a cell the lime of which has been nearly extracted by means of hydrochloric acid. (After L\u00f6wig and K\u00f6lliker).\nb. Incrusted cells of Botryllus violaceus. a, spherical cell ; b, cell with two colourless prolongations ; c, with three ; d, with four ; and e, with only one such prolongation.\nC.\tSiliceous concretions from the test of Salpa maxima, magnified 350 times. (After L\u00f6wig and K\u00f6lliker').\nD.\tCalcareous concretion from test of Leptoclinium maculosum. (After Milne-Edwards.)\nare composed of a single or manifold series of granules, which, as they approach the exterior, increase or lessen in number, but always diminish in size. These do not appear to be carbonate of lime, not being soluble in hydrochloric acid ; and their behaviour with muriate of barytes shows that they are not formed of sulphate of lime ; probably they are siliceous. The granules and nuclei are dissolved by boiling in solution of soda ; but the homogeneous substance, composing the mass of the tunic, remains unchanged.\nThe test of Salpa bicaudata is essentially the same, in the nature of its composition, as that","page":1196},{"file":"p1197.txt","language":"en","ocr_en":"TUNICATA.\t1197\nof the Salpa maxima, the fundamental mass of the gelatinous envelope being composed of the homogeneous substance. It differs, however, in the elements contained in this tissue, and by the presence of a simple layer of epithelial cells, covering it on the interior surface of the test. In the interior layer of the homogeneous substance there are granulated vesicles, having a diameter of O'OOS'\" to 0\u2018004<\"', sometimes having the appearance of nuclei, and sometimes that of cells. In the middle part, here and there, are scattered round or fusiform nuclei ; and in the exterior layer are little crystals, round nuclei, and peculiar concretions, similar to those of Salpa maxima. Some of these concretions are small, elegantly ramified, and disposed horizontally ; others are larger, ramified in a brush-like form, and appearing to the naked eye as white tufts. These latter commence at the surface, descend vertically towards the interior, and ultimately form a tuft of fine ramified rays (fig. 775. d).\nFig. 775.\nd & d\nTransverse section of the test of Salpa bicaudata,\nmagnified 30 times. (After L\u00f6wig and K\u00f6lliker.')\n1, epithelial layer; 2, homogeneous mass, with nucleoli; b, fusiform and ramified concretions; c, nuclei ; d, brush-like concretions.\nMagnified 350 times, these two sorts of concretions are seen to be composed of opaque granules of different sizes. The chemical composition of the test of this Salpa is identical with that of the preceding species.\nIn the Pyrosoma giganteum, the common envelope of the individuals is also formed of a homogeneous and structureless substance. In its interior are scattered here and there round nuclei, and some ramified, cells, similar to those of the loose cellular tissue of the embryos of Mammifers, for example, to that of the gelatine of Wharton. Both of these latter elements disappear when treated with soda; but the homogeneous substance altogether resists the action of the soda, and remains intact.\nThe Diazona violacea (Fam. Botryllid\u0153) possesses, in the gelatinous mass of the common test, a diaphanous, structureless substance, quite destitute of cells. In the exterior layers are crystals and concretions of carbonate of lime, vesicles with violet-coloured granules, fat granules, and, particularly towards the interior, a great quantity of minute round vesicles (nuclei). Treated with hydrochloric acid and with soda, the crystals, nuclei, and pigment-cells are dissolved, but the homogeneous substance remains un-\nchanged. Moreover, after having been a long time exposed to the influence of the alkali, and although the pigment-cells have disappeared, some portions of the exterior parts retain a pale violet tint, giving evidence of the presence of undissolved colouring particles, and of an amorphous colouring matter pervading the mass.\nThe structure of the test of Didemnum can-didum (Fam. Botryllid\u0153) is quite different from that met with in any of the Tunicates before mentioned. The white substance in which the individual animals are lodged, which has been figured also by Savigny, apparently presents only some white star-shaped bodies (fig. 774. A), measuring O'OO\u00f4^ to ODl\u00f6'\", similar to those found by M. Milne-Edwards, in Leptoclinum stellatum and L. maculosum (fig. 774. i>), except only that the former are of a more rounded form, and are provided with shorter and more numerous points.* But, on being treated with hydrochloric acid, this substance has quite another appearance. The white colour quickly disappears, bubbles of gas being freely given off ; and, on examination with the microscope, there is seen in the yellowish, transparent membrane that remains, a fundamental homogeneous substance, in which are scattered round and elongated cells, of O'OO\u00f6\"'\u20140*013w in diameter, and some minute granular masses. At first sight these cells appear to be analogous to the large cells found in the tests of Ascidia and Clavellina, being, like those of the latter, non-nucleated, indistinctly marked by a pale, delicate contour, and having perfectly liquid contents. But by boiling with soda they are quite dissolved, whereas the homogeneous substance remains unchanged. MM. L\u00f6wig and K\u00f6lliker found also, that under the influence of hydrochloric acid each of the star-like corpuscles showed itself not to be a simple concretion, but, losing its rays little by little, became a cell filled with lime, and ultimately appeared as a colourless, empty cell, quite similar to those above described. They add that they could not discover how these curious cells, filled with lime, and furnished with calcareous rays externally, were formed ; but they thought it probable that they were originally large cells, full of liquid, which became gradually occupied with lime, until ultimately the membrane of the cell became incrusted, and the lime deposited on its external surface.\n* We have been favoured by Mr. Bowerbank with an opportunity of examining his valuable series of microscopical preparations of ascidian tissues, including several kinds of the spicul\u00e6 entering into the composition of the tests. The spicul\u00e6 of Didemnum are spherical bodies, closely invested with short, thick, blunt spines, and nearly resemble the globular spicul\u00e6 of Tethea, except that the investing spines of the latter are more numerous and much finer. The tissue occupied by these closely set spicul\u00e6 in the Didemnum is seen in the transparent portions of Mr. Bowerbank\u2019s beautifully mounted specimens to be composed of diaphanous, contiguous, irregularly hexagonal cells, the measurements of which we have not had time to effect. Numerous nucleoli are disseminated throughout the tissue.","page":1197},{"file":"p1198.txt","language":"en","ocr_en":"1198\nTUN1CATA.\nThe common test of Aplidium gibbiilosum presents a homogeneous substance with some scattered nuclei, and a great quantity of round cells, with very delicate membranes, measuring 0\u2018005/// to 0\u2018013///, and even to 0,02///. Those in the interior contain only a liquid ; but the nearer they approach the exterior, the more are they found to contain calcareous concretions; and, lastly, there are cells perfectly incrusted, but without appendages. Acted upon by soda and by hydrochloric acid, the homogeneous substance alone remains, the rest is dissolved.\nIn the \u201c common body \u201d of Botryllus vio-laceus are some remarkably incrusted cells, similar in some respects to those of Didemnum. Some of these are perfectly round, with a diameter of 0\u2019009'\", and, as those of Aplidium, are filled with calcareous concretions ; others, for the most part pyriform or fusiform, have one or two pointed, colourless prolongations, O'OO\u00f4'\"\u20140'009/v in length, and are organic in substance ; others, lastly, round or tetrahedral, have even three or four of these prolongations, which are often of a similar length, and are regularly disposed, but just as often are of different sizes, and without symmetry (fig.774. b).* These prolonged cells are probably analogous to the round cells in Didemnum, that have lime in their interior and calcareous deposits externally, and may even be compared with vegetable cells (pollen-granules, spores, &c.), bearing external deposits. Were these cells incrusted, they would form star-like bodies, similar to those of the Didemnum.\nProfessor M. Edwards observes, that in Lep-toclinum the substance of the tissue is crowded with calcareous granules, which, seen with an ordinary lens, appear to be little spherical concretions, but which are aggregations of little pyramidal crystals, united by their base, so as to represent'a many-rayed star, surmounted on each of its faces by a group of other similar, but smaller, rays (see fig. 774. d).\nThe structure of the common test of the Botryllus polycyclus is peculiar and quite different from those described above. In the exterior parts of the common mass the structure resembles that ordinarily found in compound Ascidians, being of a clear and homogeneous substance, with some nuclei and crystals; but in the interior distinct fibres are found, by the side of the nuclei. These fibres are of two kinds; some, the least numerous, are long, extremely pale and delicate, too fine to be measured, and, crossing one another in all directions, form elegant sinuosities ; others, less numerous,are short, (VO l/\" toO-03'\" in length, larger, opaque, and variously curved; in a word, they resemble certain nuclei transformed into fibres (Kernfasern). Like the homogeneous substance of the exterior and interior parts, these fibres resist the action of hydrochloric acid and of soda ; and consequently,\nsince they are incontestably organic, they are composed of non-azotised substance.\nThere are also some round points, visible to the naked eye, dispersed in the common integument of this Botryllus. Some are white, generally situated towards the interior of the test, and appear under the microscope as groups of granules or spicul\u00e6 ; they are insoluble in a solution of soda, or in hydrochloric acid, and are probably siliceous, like the concretions in Salpn. The other spots are violet-coloured, or reddish, and are most abundant in the external layers near the groups of individuals, yet sometimes also they are present in the interior parts of the common mass. Seen under the microscope, they appear as pyriform, round, or elongated vesicles, bearing a reddish colouring matter, contained probably in the cells, and are attached to the extremities of the ramifying canals that traverse the mass in every direction. These vesicles are the germs of new individuals.*\nThe coriaceous test of the Cynthi\u00e6 (Fam. Ascidiad\u0153) presents a composition still more remarkable than that of the Botryl/i, In Cynthia papillata, the fibres that constitute a large proportion of the test, are in some parts so much developed, that they may bear comparison with the fibrils of any fibrous tissue found in vertebrate animals.\nIn examining the structure of the test, where it is of no great thickness, we find a simple lamina, quite on the interior surface, consisting of an epithelium, with polygonal cells, which is united to the mantle by scattered, crossing, muscular fibres. A thick layer of fibres succeeds, having cells and nuclei disseminated in it. The fibres themselves are colourless, undulating, resembling the fibrils of the fibrous tissue of vertebrate animals, but narrower ; they measure (V0002\"'\u20140,0004/// in thickness ; they are never ramified, nor united into bundles. In their direction they are in part parallel to the axis of the animal, as in the interior laminae ; and in part differently interlaced, so that some are disposed longitudinally, and others transversely (circular and longitudinal fibres) ; hence, from the disposition of the two kinds of layers, the test can very easily be split into, sometimes very delicate, laminae. There is apparently no intermediate substance accompanying the fibres, but the laminae formed by their divergences are occupied by a quantity of granules and vesicles of different forms. Firstly, there are minute colourless molecules, in some parts so abundant as to render the fibres indistinct, and to give to some of the thicker layers a finely granular aspect; secondly, crystals, which are present only in the exterior layers ; thirdly, nuclei, measuring O\u2019OOl'\" to 0 003///, often with large granules, apparently of fat ; fourthly, cells of different forms. Some of these cells, containing nuclei\n* Specimens of these spicula in Air. Bowerbank\u2019s * The epiderm covering the common gelatinous histological collection exhibit much more coarsely test of Botryllus stellatus is very tough, closely ad-granulated centres than those here figured.\therent, and presents distinct cellular structure.","page":1198},{"file":"p1199.txt","language":"en","ocr_en":"TUNICATA.\n1199\nand brown pigment-granules, are round, having a diameter of O'OOo'\" to O\u2019Ol'\", or elongated, with a diameter of O\u2019OOG'\" to O\u2019OOS'\" ; others are of a pale colour, and, from the double nuclei and the included cells (2 to 7) seen in some of them, strongly resemble the cartilage-cells of the superior animals. This resemblance is rendered the more striking by the round or elongate form of these cells, by the peculiar arrangement of the enclosed cells, and by the union of some of the mother-cells, in this case generally round and smaller, into groups of two or four. This resemblance, however, is only external, and due only to the fact that the cells increase by formation in the interior, as in cartilage ; because more exact observations show that these cells, by further transitions, become identical with the simpler pigment-cells described above, and are only the more developed forms of the latter, the pigment having disappeared by degrees on account of the condition of their growth.\nThe third layer is formed of a 3'ellowish, horny epidermis. The thin hairs which cover the surface of the Cynthia papillota are formed by this and the exterior fibrous layer. At certain spots a bundle of fibres springs up from the plane surface of the latter, which, being coated with the horny epidermis, rises on the surface as small needle-shaped bodies.\nWhere the test of the Cynthia attains a thickness of i to i\\\"r and more, its composition often changes in a remarkable manner {fig. 776.). In this case the epithelium is succeeded\nFig. 776.\nTransverse section of Cynthia papillota, magnified 100 times. (After L\u00f6wig and K\u00f6lliker.')\n1, Internal layer of epithelium; 2, second layer, homogeneous, with pigment-cells; 3, third layer, composed of alternate layers of radiating fibres and fibres parallel to the surface of the test ; 4, fourth layer, fibres parallel to the surface of the test; 5, spines; a, the thin yellowish outer surface; b, fibrous nuclei.\nby a clear, homogeneous, structureless mass, of a moderate thickness, with scattered pigment-cells and nuclei. Next is a fine fibrous tissue, composed of a great number of thin layers of circular fibres, without cells or nuclei, and of radiating fibres that unite these layers ; this passes externally into an irregular fibrous tissue, covered with a horny epidermis. Where this peculiar stratification of fibres exists, the test is not separable into laminse, because the radiating fibres firmly connect the thin layers of circular fibres.\nTreated with hydrochloric acid and with soda, the test of Cynthia is rendered quite white. The pigment-cells, the coloured epidermis, the mother-cells, the crystals, the epithelium, the nuclei, and the granules are dissolved, and there remain only the fibres and the homogeneous substance that exists here and there. These two elements, then, are composed of cellulose.\nThe structure of the thick test of the Cynthia Canopus is very similar to the above. Interiorly there is an epithelium, then a thick layer of longitudinal and circular fibres, somewhat indistinctly stratified, in which, towards the exterior, crystals and largish round bodies, composed apparently of groups of cells, are disseminated ; lastly, a thin layer of solid, whitish epidermis, with little conical papillae, usually accompanied by processes from the fibrous layer. The thick fibrous layer, only, resists the action of hydrochloric acid and of soda ; all the rest is dissolved without any residue.\nCynthia pomaria presents, as the chief material of its test, a layer of fibres similar to those previously described, having chiefly a longitudinal direction. Between the fibres are crystals, round pigment-cells, measuring 0 004wto 0\u2019006w, and further, here and there, peculiar elongated cells, filled with yellow granules, measuring (bOOS'\" and more. Internally, and adhering to the fibrous layer, is a simple epithelium, with polygonal cells that have diameters of O\u2019OOG'\" to 0,008/|,/. This adheres to the inner tunic by means of muscular fibres. Externally the fibrous layer is covered by a yellowish, solid layer of undetermined structure. In the interior parts of the fibrous layer occurs a somewhat large number of peculiar cells, apparently not analogous to any other of animal or vegetable structure. These cells are primitively similar to pigment-cells, and round, but possessing a thicker membrane, and without any apparent nucleus. Subsequently they grow, preserving their shape, to the size of O'Ol\"'. The membrane at the same time continues to thicken, so much so that the cavity of the cell increasing but slightly, the membrane attains a thickness of O\u2019OOI/\". Lastly, the size of the cell increases to 0,02/// and the thickness of the membrane to O'OO\u00f4'\". Whilst this development is going on, fine lines are observable in the thickened cell-membrane, and ultimately the membrane is transformed into fibres, so that one may see the moderately sized cells in their cavities, and yet occupied by pigment","page":1199},{"file":"p1200.txt","language":"en","ocr_en":"TUNICATA.\nor by pale granules, enveloped with an elegant skein of fine, cylindrical, opaque fibres, which can be isolated by compression. Whether the fibres have a spiral arrangement is uncertain. MM. L\u00f6wig and K\u00f6lliker, who discovered these remarkable fibre-coated cells, remark that, as to the manner in which this curious transformation of the pigment-cells is brought about, the increase of thickness in the cell-membrane would take place by growth, or by a development similar to that which occurs in many vegetable cells, the membrane of which consists of several layers, or by the deposition of a substance applied externally. As there is no appearance of any internal or external deposit, and as the cell-cavity is not diminished during the thickening of its walls, they consider the first to be the more likely cause of the above conditions, but, nevertheless, not sufficient alone to account for the circumstances. It is difficult, perhaps, to say how these fibres are formed, but it may be that the cell-walls, by partial solidification, ultimately become separable into fibres.\nThe fibrous tissue of the Cynthia pomaria is insoluble in hydrochloric acid, or in solution of soda ; the other elements of the test, submitted to these agents, disappear.\nThe following clever abstract of the facts connected with the subject has been drawn up by Professor Edward Forbes : \u2014\n\u201c MM. L\u00f6wig and K\u00f6lliker found cellulose undoubtedly present in the envelopes of many Tunicata, both simple and compound, including the genera Phallusia, Cynthia, Cla-vellina, Diazona, Botryllus, Pyrosoma, and Salpa; but they sought in vain for cellulose in animals of interior organisation, although in some of the above-named creatures it formed a very considerable part of the animal tissues.\n\u201c The Memoir of MM. L\u00f6wig and K\u00f6lliker was examined by a committee of the French Institute, consisting of Dumas,Milne-Edwards, Boussingault, and Payen ; the last-named eminent philosopher drew up the report. In it he gives the following formula of the composition of the envelopes of the Tunicata : \u2014\nCellulose\t60-34\nAzotised substance\t27-00\nInorganic matter -\t12-66\n\t10000\nHe remarks that the\testablishment\nthe existence of cellulose in the Tunicata is a \u00a3 fait capital\u2019 in science, very important in its bearing on future researches into the comparative physiology of the two kingdoms.\n\u201c The explanation offered by L\u00f6wig and K\u00f6lliker of these very anomalous facts is extremely ingenious, and probably very near the truth/ It is to the following effect: \u2014 Tuni-cata live entirely upon vegetable organisms. The contents of the stomachs of the Phal-lusi\u0153, Clavellin\u0153, and Diazon\u0153, examined, consisted of particles of florideous algae, which had probably found their way there by chance, and a great quantity of microscopic plants of low position in the series, species of Navicula,\nFrustulia, Baccilaria, Closterium, &c. These minute vegetable organisms have been shown by Nageli and Schmidt to contain cellulose.\n\u201c This is probably dissolved by the gastric juice, that is to say, changed into sugar or gum, in which state it circulates with the blood, and is afterwards introduced into the tunics, either directly by the sanguiferous canals (as in Phallusia), or by their prolongations ramified in the walls of the common body (as in Diazona and Botryllus), which thus, as Milne Edwards has shown, contain also blood in their cavity, probably penetrating by imbibition when the envelopes have no bloodvessels. The presence of cellulose in the tunics of the ascidian Molluscs, then, cannot be taken as an evidence of an approach to a vegetable nature in those bodies. It affords us, however, a wholesome warning against the placing of confidence in asserted chemical distinctions between the great kingdoms of Nature.\u201d *\nFrom the observations made by MM. L\u00f6wig and K\u00f6lliker on the histological characters of the embryos of certain compound Ascidians, they arrived at two important results. Firstly, that the external structureless envelope of the embryos, which, apparently, is identical with the external envelope of the adults, is, according to their analysis, composed of cellulose ; that this envelope is formed only when the division of the yolk is accomplished, and even when the exterior form of the embryo is indicated. Secondly, that this envelope, subsequently containing, as in Botryllus and in Aplidium, another structureless substance, fibres, nuclei, and crystals, is primitively altogether homogeneous and unorganised.\nHence it appears that the test of the Tuni-cates is a product of the activity of cells formed subsequently to the processif the division of the vitellus, and that primitively it is only a mass secreted by these cells. Its ulterior organisation is not yet understood, but remains an open field for much interesting and important research.\nAnatomy of the Ascidiad\u00e6.\u2014We have already referred to the external envelope of the Tunicates as being analogous to the cal-ciferous shells or tests of the other Acephalans; and the muscular sac enclosed within it, as the analogue of the mantle ; and the membranous sac lining the mantle as analogous to the branchiae of the Acephalans. f\nThe rest of the viscera of the Ascidians are enveloped in a peritoneumj, and the heart has, besides, its own membranous sac or pericardium. Thus the body, properly so called, appears as if divided into three cavities ; that of the branchiae, communicating with the exterior by the superior opening of the sac,\n* Hist. Brit. Molluscs, vol. i. p. 6.\nf According to Yan Beneden, the longitudinal vessels of the branchiae of the Ascidi\u0153 are more particularly the analogues of the ciliated tentacles of the Bryozoa.\nJ The peritoneum of Ascidia intestinalis offers a good example, being of firm consistence, circumscribing and protecting the abdomen.","page":1200},{"file":"p1201.txt","language":"en","ocr_en":"1201\nTUN IC ATA.\nand in the base of which opens the mouth; that of the peritoneum, which does not communicate with the exterior by itself, but is traversed by the intestinal tube, which, arising in the branchial cavity, communicates with the exterior by the rectum and the anal aperture of the test ; and, lastly, that of the pericardium, which has no direct communication with the exterior.\nThe position of the animal is always such, that of the two orifices the branchial is always the highest ; the entrance into the branchial sac being generally placed at or near the superior extremity of the body, and the oesophageal opening, at the base of the branchial sac, having an upward direction. In Boltenia and Cystingia the flexible peduncle, which is attached at the summit of the body, above the branchial orifice, allows the body to droop, thus giving the animal its normal position. In the Clavellinid\u00e6, which have rigid peduncles continuous with the base of the test, the same normal relation of the internal parts is preserved ; and although the intestinal loop in jBoltenia and C/avellina is always directed towards the pedicle, yet this arises from the loop having, in the former an ascending, and in the latter a descending, direction.\nThe muscular sac or mantle, enclosed in the external envelope, is attached to the internal surface of the latter by an adhesion of the external surface of the extremities of its two tubular processes, which correspond to the two external orifices of the test, to the inner borders of these outer orifices (fig. 780.). In Ascidia there is often no intimate cohesion at these points, merely an adaptation easily disturbed after death. In Cynthia, Boltenia, &c., on the contrary, the test and the tubular prolongations are strongly adherent. Beside this mode of attachment, there is sometimes a general loose adhesion formed by the epithelial tissue between the surfaces of the test and mantle ; and in Cynthia papillata there is a partial transmission of muscular fibres from the latter to the former ; and, lastly, there is the very slight attachment arising from the passage of bloodvessels from the body to the test.\nThis free condition of the mantle within the external sac occurs throughout the Asci-diad\u00e6, Clavellinid\u00e6, Botryllid\u0153, and Pyroso-mid\u00e6. In the Salpid\u00e6 and the Pelonaiad\u0153, on the other hand, the mantle and the test are connected at very many points, or even throughout the extent of their contiguous surfaces.\nThe mantle in Chelyosoma is more closely attached to the internal surface of the test than in other Ascidians ; its muscular tissue forming intimate connections between the various plates of the external envelope, and not only supplying the valvular pieces of the apertures, but also edging each of the larger plates with interlacing connecting fibres. Except at these muscular spaces the mantle appears as a thin serous membrane.\nThe interval between these two sacs is, during life, filled with some fluid ; possibly a\nVOL. IV.\nsecretion, or transudation through the one or the other of these envelopes ; for, except in the case of those Ascidians whose mantle-tubes are not intimately connected with the test, the sea-water cannot be directly admitted into this cavity.\nThe mantle is reflected upon the body, properly so called, and covers it externally, just as the peritoneum, after having coated the walls of the abdomen, is reflected upon the intestines ; with this difference, however, that it has no mesentery, and that the connection is only at the two orifices. It has an external serous layer, continuous with the internal membrane of the test, a muscular tissue more or less extensive, and an internal serous layer. It has also numerous ramifications of nerves and bloodvessels. In Boltenia, Cystingia, and probably Bipapillaria, a tubular prolongation of the mantle traverses the peduncle.\nThe two tubes on the superior aspect of the mantle, which are directed towards, and protruding into, the two somewhat tubular orifices of the test, are more muscular than the rest of the sac, being surrounded with, generally very distinct, sphincters in addition to the fascicles of muscles that traverse them longitudinally, and are continued diagonally across the sac (fig. 780.). When open, the margins of these tubes are crenulate. The free extremity of the branchial orifice is sometimes quite entire, but occasionally terminates in a circle of regular tooth-like processes, which are regarded bv Dr. A. Farre as the analogues of the tentacles of the Bryozoa. By contraction, the tubes are thrown into 5 or 6 folds. At the exterior angles of these folds in some Ascidians (A. intestinalis, Cynthia ampulla, &c.) there is a minute red spot ; in A. mammillata, the edges of the folds are more or less reddened by an increase and diffusion, as it were, of these little red granules. Internally each tube has frequently at its base some slight valve-like prominences or folds; and the inner extremity of the branchial tube is always fringed with a circlet of simple or compound tentacular filaments. These, however, may more properly be said to belong to the branchial sac.\nThe mantle becomes dusky and opaque, and its muscular tissue more distinctly seen, in preserved specimens. In its recent state it is more or less diaphanous, and usually of a sober tint ; but occasionally, in Ascidi\u0153, it is of a fine crimson (A. venosa), or variegated with crimson and white (A. virgin nea), or spotted with red (A. aspersa) ; and in A. parallelogramma it is ornamented with rectangular reticulating white lines and occasional bright yellow or crimson spots. In A. conchilega it is white, passing to blue ; and in A. arachnoidea it is dark blue.\nThe branchi\u00e6 of the Ascidiad\u00e6 is a large bag of fine vascular network furnished with vibratile cilia, contained within the mantle of the animal, and lining the walls of that cavity (fig. 778.). Sometimes the branchial sac is oblong, oval, or rectangular ; and then\n4 h","page":1201},{"file":"p1202.txt","language":"en","ocr_en":"TUNICATA.\n1202\nit occupies all the length and one of the sides of the cavity of the mantle (Cynthia). In Ascidia mammillata and A. monacha it is very long; and, after having descended to the bottom of the mantle, it is bent upwards upon itself, extending half way up the cavity again.\nA tube, differing in size in various species, which has its analogue, perhaps, in the retractile operculum of the Bryozoa, conducts the water from the buccal aperture to the respiratory sac. This tube or process of the mantle encloses the neck of the branchial sac. At the inner extremity of the tube, where it widens into, and is continuous with, the branchial sac, are frequently observed about five small valvular folds ; and below these there is always a circle of fleshy filaments or tentacular appendages {fig. 778. and fig. 39 d. Vol. I. page 112. Animal Kingdom*). These are present also in the Claveltinidce and the Botryllid\u00e6. They vary from 6 to 26 in number, and are either simple, as in Phallusia, or branched, as in Cynthia, Boite nia, &c. By detaching the anterior part of the respiratory sac of Cynthia, or others, and examining it from its inner and inferior aspect, one may perceive, at the inner margin of the tube, several arboriform appendages, somewhat large at the base, and having the branches either swollen at their extremities, or finely laciniate and almost plumiform : in Cynthia Dione they are somewhat bipinnate. The number of the tentacles is difficult to be arrived at, as smaller filaments appear amongst the six or seven larger ones. The branches are generally directed downwards, towards the bottom of the sac, but sometimes are slightly curled upwards. Seen under the microscope, these filaments are hollow ; and the extremities and swellings of the branches are cul-de-sacs. The several tentacles intercommunicate with each other by their hollow bases, and with the vascular network of the respiratory sac.\nThe walls of these tubular organs are very thin and transparent ; traces of muscular fibre have been detected in their substance, and a circulation ; but no trace of vibratile cilia, either on their outside or within their cavity. Van Beneden observes that a fluid traverses their cavity in a similar manner to the blood in the branchi\u00e6 of the Doris. In Actinia and Holothuria simple and ramified filaments occur, that offer considerable analogies to the arborescent tentacles of Ascidice. They are all hollow ; and the fluid moving in their interior comes directly from the peri-intestinal cavity ; this great cavity, communicating as in Bryozoa, with the tentacular appendages.\nThe internal surface of the respiratory sac is sometimes uniform (in Ascidia, Phallusia, &c.), and frequently longitudinally plicated and disposed in deep and regular folds, all following the curve of the cavity, and termi-\n* This figure represents a Cynthia canopus cut open ; a, oesophagus; b, stomach; c, anus; d, external anal orifice, closed ; e, branchial orifice, laid open ; /, branchial tentacles ; g, nerve-ganglion ; h, dorsal sinus; k, ovary (?) ; i, l, indeterminate bodies.\nnating at a little smooth area above the pharynx (Cynthia, Boltenia, &c.). The folds are from 8 to 18 in number, and form the first indication of the four branchial laminae of the bivalve Acephalans. The structure of the membrane consists of an infinity of small, anastomosing vessels, generally crossing each other at right angles, and forming quadrangular interspaces, which, under the microscope, are seen to be still more minutely subdivided in the same manner. Milne-Edwards observes that in Phallusia each of the meshes of the respiratory membrane is occupied by a minute spiracle, that allows of a communication between the interior of the branchial sac and the cavity of the mantle (the \u201cthoracic chamber\u201d of Milne-Edwards), the dorsal portion of this chamber being the cloaca, the base of which is occupied by the orifices of the digestive and generative tubes, and the summit of which opens externally by the anal aperture. In Cynthia ampulla the meshes are very irregular and almost inextricable, some of the minute vessels having apparently a spiral arrangement ; and the vessels are rather more numerously disposed around the oesophageal orifice. A somewhat spiral or vermicular arrangement of the extremities of the branchial vessels exists also in Chelyosoma, as figured by Eschricht ; * and as seen in a very minute sessile Ascidia, from South America, in the collection of Mr. Bower-bank. In the respiratory network of Cynthia the large longitudinal vessels are seen to be the most prominent of all. They form, with the large transverse vessels, square meshes, which three other shorter vessels subdivide into four transverse meshes; and these are further intercepted by extremely fine longitudinal vessels. The vertical vessels of this quadrangular network may be said to arise from the transverse vessels, which communicate by each extremity with two vertical trunks, placed at opposite sides of the sac, and representing respectively the branchial artery and vein. The latter, in C. microcosmus and other As-cidians, bears a longitudinal series of small transverse tentacular filaments. Similar tentacles we shall have to describe as belonging to Chelyosoma (fig. 777. i).\nThe angles of the meshes of the branchial tissue bear papillae, more or less prominent, in some genera {Ascidia, Chelyosoma, &c.) ; but in others they are not papillated ( Cynthia, &c.). These papillae, or minute pouches, are, according to Savigny, analogous to the filaments that border the branchial vein, in most of the simple and compound Ascidians, indicating the junction of the transverse vessels with that vein. The appearance of the reticulation is large and coarse in Cynthia, minute in Ascidia, and indistinct in Cystingia.\nEach mesh of this respiratory network is thickly fringed with vibratile cilia, as in the rest of the Tunicates and Acephalans ; and Van Beneden points out that this ciliated exterior of the branchial vessels is analogous to the ciliated tentacles of the Bryozoa. By the\n* Roy. Danish Transact, vol. ix. pi. 1. fig. 6 & 7.","page":1202},{"file":"p1203.txt","language":"en","ocr_en":"TUNICATA.\naction of the cilia the currents are sent in the direction of the oesophageal aperture.\nIn Ascidiapapillosa and Cynthia microcosmus, a little soft tubercle is situated on the interior of the branchial sac, not far from the orifice, between the two branchial veins, not observed in other Ascidians, but seen in all the Botryl-lians. On the internal surface of the sac are also seen several prominent lines, 12-15 in A. mammillaris and A. papillaris, 5-6 in C. ampulla, more or less distant from one another according to their length. These are folds forming gutters converging towards the mouth, and having also transverse channels leading from one to another. Above they appear to terminate in culs-de-sac. The vibratile cilia covering them are very long and numerous.\nVan Beneden found that, on placing for a short time a living Ascidian in water coloured with carmine, the particles of the colouring matter quickly filled these little ducts, making them appear like injected vessels. This distinguished naturalist considered them to be somehow connected with the digestive apparatus, moulding, perhaps, the particles of food into cord-like masses before entering the stomach.\nIn Chelyosoma (fig. 777. i) there is a remark-\ning. 777.\nAnatomy of Chelyosoma Macleayanum. (After Eschricht.)\nThe inner or under side of the superior plated surface of the animal is shown, the branchial cavity being split open, and the abdominal viscera removed. a, branchial orifice, partly closed by a membrane, and surrounded by its hexagonal sphincter muscle and the accompanying six fanshaped muscles ; b, anal orifice, similarly provided with muscles ; c, c, muscles bordering the carapace-plates ; d, the central hexagonal plate ; e, e, e, e, the surrounding plates ; f the nerve-ganglion and nerve-fibres ; g, h, the auditory apparatus ( ?) ; i, the row of tentacles anterior to the oesophagus; j, stomach ; k, part of the intestine.\n1203\nably large row of simple tentacles running from the interior of the branchial orifice to the entrance of the oesophagus, and closely connected with the branchial tissue, as in Cynthia microcosmus, &c. They appear to surmount a longitudinal vessel or duct, possibly the branchial vein ; they are about 23 in number, and have a transverse direction towards the left side. The posterior tentacles are the largest, of about a similar size to the tentacles of the branchial orifice; the others, towards the anterior extremity of the row, become gradually smaller. Their use is not very evident ; possibly they are connected with the organs of digestion ; but, more probably, they are auxiliary respiratory organs, like the circlet of tentacles within the branchial tube.\nThe respiratory cavity, in addition to its external or oral orifice and its oesophageal aperture, presents also, in some cases at least, a lateral opening, first noticed by Cams*, and since by Van Beneden. The presence of this communication allows the water, received into the branchial sac for respiration and the conveyance of food, to pass directly out by the anal aperture. Otherwise, when no such communication exists, the water must be ejected through the oral aperture by muscular contraction, as in the Acephala.\nIn Clavellinid\u00e6 and Botryllid\u0153 the open meshes of the respiratory network f, or branchial stigmata, also allow of the free passage of water from the respiratory cavity to the cloaca. In Pyrosoma, Pelonaia, and Salpa, the disposition of parts admits of the free passage for the water from the one external orifice to the other.\nExternally the branchial membrane presents very similar appearances to its net-like interior surface : where folded, however, of course the folds and sulci are reversed. It is attached more or less firmly to the inner surface of the mantle on the one side, and on the other to the intestines, stomach, and ovaries, by transverse, short, delicate, perhaps vascular, threads, one of which proceeds from each angle of the meshes.\n\u201c In the young Ascidian,\u201d says Cams, \u201c the respiratory sac can be distinctly recognised as an integral part of the intestinal canal. As the body increases, this originally crop-like dilatation gradually attains a more considerable extent, and differs in structure from the intestinal canal in having exceedingly delicate and transparent parietes ; in a word, diverging more and more from the intestine.\u201d\nWe may further observe, that the vertical vessels entering into the composition of the framework of this branchiferous pharyngeal sac, and representing, according to Van Beneden, the tentacula of the Bryozoa, are not only analogous to the latter in their respiratory function, but are subservient also to the purposes of alimentation, like the tentacles\n* Meckel\u2019s Archiv f. Physiologie, B. ii. 1. 4.\nt M. Coste (Comptes Rendus, vol. xiv. p. 182. 1844) denies the existence of open stigmata.\n4 h 2","page":1203},{"file":"p1204.txt","language":"en","ocr_en":"TUNICATA.\n1204\nreferred to, by producing, and being traversed by, the ciliary currents that bring the food to the oesophageal aperture ; and that the ten-tacula of Bryozoa are essentially members of the alimentary apparatus is shown by the fact, that animalcules, &c. are frequently caught and detained by the action of the tentacles, one or more of which, and sometimes even the whole, bend suddenly inwards, and secure such particles as come within their reach, thus taking the character of prehensile labial or oral appendages. *\nThe cavity of the branchial sac is often the habitation of parasitical Entomostraca.\nThe buccal or branchial orifice of the Asci-dians terminates, as we have already noticed, by a valvular opening in the large delicate membranous sac, which in some respects appears to be a kind of crop, and in others a respiratory cavity. Opposite to it, and in the lower part of this cavity, is the commencement of the oesophagus (fig. 778. d), which leads to the stomach and thence to the intestine. The viscera are always more or less\nV II il\nAnatomy of Dendrodoa glandaria, magnified about 3 times. (After MacLeay.')\na, summit of the test open and thrown hack ; b, upper part of the branchial sac opened and thrown back with the test, so as to expose its inner surface and the circlet of tentacles surrounding the inside of the branchial orifice ; c, the ventral sinus ; d, oesophageal aperture ; e, stomach ; f intestine ; g, anus ; h, inner aspect of the external anal orifice ; i, nerve-ganglion, situate between the two external orifices, and cut through in opening the animal ; j, part of the test or external envelope ; k, k, branched ovary, single, and on the left side.\nlateral, except in Chelyosoma, where they are disposed flatwise, below the branchial sac. The convolutions of the intestine are placed between the respiratory sac and the muscular envelope or mantle, and are either unattached, except by slight filamentous processes arising from the external surface of the branchial sac, or buried in the substance of the liver and ovaries.\n* Mr. A. Hancock, on the Anatomy of the Freshwater Bryozoa, Annals and Mag. Nat. History, 2d series, vol. v. p. 176. See also Lister and Farre, loc. cit.\nThe mouth, or oesophageal orifice, is at the base of the branchial sac ; so that when the latter extends to the bottom of the cavity of the mantle, the mouth is also at the base of the mantle. When the branchial sac stops short at the middle of the muscular sac, or when it is bent upon itself, the mouth also is near the middle. In the species that have an oblong, transverse cavity, the mouth is at the postero-inferior angle of the branchial sac. The mouth is either a simple round hole or a slit, or it is an aperture divided up by slight folds or ridges. It is always destitute of lips","page":1204},{"file":"p1205.txt","language":"en","ocr_en":"T\u00dcNICATA.\n1205\nor tentacles, unless we except the peculiar longitudinal row of tentacles passing forward from the oesophageal aperture along the wall of the branchial sac in Chelyosoma and other genera. The oesophagus, sometimes obsolete, is always very short, and is more or less plicated longitudinally.\nThe stomach is simple, generally merely a slight dilatation of the alimentary tube (figs. 777. j, and 778. e). In A. mammillata it is strongly plicated, and the pyloric extremity narrowed by little fleshy papillae. It is sometimes bent upon the intestine and adherent to it, and is often enveloped in the liver, with which it is intimately adherent. Its walls are very unequal, internally forming various lacunae, through which the bile penetrates, as in the Bivalves ; the little bile-ducts are guarded with valvules. In JSoltenia reniformis the stomach is destitute of any internal folioles or lacunae ; but in Ascidia intestinalis, Cynthia \u2018papillota, C. canopus, and others, internal plicae are present ; and in C. ampulla the stomach is almost filled up with longish folioles, and is of a light yellow colour from numerous yellowish granules contained in its tissue.\nIn Dendrodoa the stomach is striated externally (fig. 778. e). In Cystingia it is very large, extending almost the whole length of the body, and bears externally a deep longitudinal depression, and is marked internally with faint transverse striae. In Cynthia poly-carpa and C. pomaria, a little c\u00e6cum occurs just anterior to the pylorus.\nThe intestine is usually short, simple, and without coeca. In several species of Ascidia its internal surface is traversed throughout nearly its whole length by a semicylindrical, hollow, ridgelike plication, the \u201c intestinal rib\u201d of Savigny, having the appearance of an inva-ginated intestine. In its course, the intestine generally makes one or two folds. Its walls are thickened frequently by a glandular tissue, probably supplying some fluid necessary to digestion ; and its internal surface sometimes bears biliary lacunae. The rectum leaving the peritoneum floats unattached, and opens opposite to the second or anal orifice of the mantle, so that the excrements falling into the cloacal cavity are carried away by the current of water leaving the body. In the stomach and intestines is usually found a mass of finely divided matter, chiefly, if not wholly, derived from diatomaceous plants. Towards the posterior extremity of the intestines the excrements are usually moulded into little earthy-looking filaments, as in most of the Molluscs. The f\u00e6ces appear to be formed into these vermiform cords in the sulcus along the side of the longitudinal intestinal fold.\nIn A. mammillata the duodenum has several slight transverse stri\u00e6. In Cynthia ampulla the intestinal walls are internally hollowed into lacunas and little folds, which, like the coats of the stomach, pour out a yellowish fluid like bile. In Dendrodoa the intestine is of considerable length. In JSoltenia reniformis also the intestine is long, mounting up as high as the base of the pedicle, then descending nearly\nparallel with itself and terminating in an ascending conical rectum, the anus having a scalloped margin. In this species there are twelve subcubical bodies, separate from each other, adherent to the upper and inner surface of the rectum, having the free edge of a part of the ovary between them and the liver. In size they differ among themselves, the largest lying towards the anus, and the smallest in the opposite direction ; they have no apparent communication either with the intestines, with each other, or externally. Under the microscope their structure appears to consist of a very fine homogeneous colourless membrane, enclosing an infinite number of excessively minute nucleated cells, readily separable from the tissue, which have much the appearance of blood globules. In Chelyosoma the digestive apparatus is large, and, from the shape of the animal, is arranged flatwise. The oesophagus commences at the posterior left corner of the branchial sac, between the two chambers of the heart. Advancing obliquely forwards, it enters the stomach, around which are clustered the biliary c\u0153ca. The intestine goes on to make a single bend, and, coming back to the left posterior corner, proceeds towards, and terminates abruptly at a very short distance from, the anal orifice.\nThe liver of the Ascidiad\u00e6 generally occurs in a very degraded form ; it is either absent, as in Ascidia, Dendrodoa, and some Cynthia?, or its place is supplied by lacunae and folioles on the inner coats of the intestinal canal, occurring, in Cynthia ampulla, both in the stomach and duodenum ; or, on the other hand, it is more or less amply developed, as in Bol-tenia, where it appears as an irregularly lobu-lated body, coating the stomach externally behind the right ovary, and passing from the lower extremity of the body, half-way up, in the cavity of the mantle. The lobes differ in size: the largest are placed towards the pyloric or highest end of the stomach, and are more distinctly separated from each other than the smaller ones ; they are more or less rounded and granulated, their surface being minutelj papillated and composed of minute round bodies, at first sight resembling ova. In Cynthia the liver is greenish, granulated, foliated, or, as in C. Dione, caniculate. It is sometimes formed of clustered groups of flask-shaped cellular bodies, the individual cells being fixed by their larger ends, and having a radiate arrangement. It is intimately adherent to the external surface of the stomach, which frequently is totally enveloped by it. The bile enters the stomach by distinct holes at the bottom of the cavities of the little lacunae before-mentioned. In C. microcosmus, and others, the liver is divided into masses, one of which is situated on the left of the branchial sac and quite free of the abdomen. The liver in Ascidia intestinalis has the appearance of somewhat salient glandular bodies, situated as well on part of the intestine as on the stomach. In Chelyosoma this organ is represented by a cluster of short ccecal tubes lying all over the external surface of the stomach. The\n4 h 3","page":1205},{"file":"p1206.txt","language":"en","ocr_en":"1206\nTUNICATA.\nliver cells in Boltenia are elongated c\u0153ca, thick, and sometimes deeply divided at the outer extremity, attached by their thin ends, and arranged in eccentrically radiated groups, enclosed in an epithelial membrane, the whole having externally a racemiform appearance.\nThe digestive organs of the Tunicata are subject to congenital malposition ; of which M. Savigny has described two remarkable examples, in Cynthia Momus and Phallusia Turcica; and Mr. MacLeay was inclined to regard as a malformation a peculiar arrangement of the intestinal canal that was presented by the unique specimen of Cystingia Griffithsii described by him. In a unique specimen of P. Turcica, examined by M. Savigny, the intestine lay to the left instead of the right of the branchial sac, and was found bending backwards and embracing the stomach from below, instead of bending forwards at some distance from the pylorus, approaching the superior border of the stomach, and then terminating in the rectum. In a specimen of C. Momus, the alimentary canal was also found on the left-hand side ; but, by a very peculiar introversion, the pharynx was placed at the posterior instead of the anterior extremity of the branchial sac. The intestine descended as far as the bottom of the mantle, folded itself forward, and ascending parallel to itself, terminated opposite to the pharynx ; so that the anus and the oesophageal aperture both opened into the branchial orifice. The external communication through the anal orifice existed as usual. Both of these malformed individuals had their ovaries full of eggs, but were not, apparently, in strong health, and were more than usually infested with, ento-mostraca. In the catalogue of the Hunterian Museum (vol.i. pl.5.y%. 2.), a dissection of an Ascidian is figured after a drawing by John Hunter (the original specimen, however, has not been found), in which there is, apparently, an abnormal elongation of the oviduct, which is accompanied by a slight granular line, both lying on a large tapering tube having much the appearance of intestine ; the anus, however, shows itself projecting from the side of this tubular body some way lower down, in its usual place. The oyiduct, and, apparently, the accompanying elongated tube, terminate externally at a minute aperture placed in the sulcus between the two projecting terminal orifices of the test. The oviduct, however, barely reaches this aperture ; and its accompanying granular line terminates still lower down.\nOrgans of circulation. \u2014 In the Ascidiad\u00e6 there are two large vessels or sinuses, the dorsal and ventral, to which the branchial capillaries, on the one hand, and the heart and peri-intestinal cavity, on the other, are intermediate. The circulation is of the mixed or reptilian type ; both sinuses being in connection with systemic and respiratory capillaries, and the blood, consequently, being sent by one impulse both to the system and to the branchiae, and ultimately returning from both by the -same channel. We are prevented\nfrom calling either of these sinuses arterial or venous, on account of the periodic reversal of the circulation, mentioned incidentally above, and more fully detailed hereafter, whereby they are alternately changed from vein to artery and from artery to vein. One of the branchial trunks, terminating at the heart, however, answers to the branchial veins of the Gastero-pods and Bivalves ; the opposite, and often double, trunk may therefore be looked upon as the branchial artery, and is connected with the veins of the body. The Ascidia, like the rest of the Acephala, has but a left or aortic ventricle, and no ventricle at the union of the vena cava and the pulmonary artery. This aortic heart or ventricle is not always easy to be seen. When the branchial sac is simply oblong, it is situated towards its base ; and consequently, when the branchial sac is as long as the body, it is situated towards the base of the mantle ; and when the sac is shorter than the body, it is placed near the centre of the mantle. When the branchial sac is bent upon itself, the heart is situated at the curve, and then it is always near the middle of the body. In general its position, according to Cuvier, appears to be determined rather by that of the mouth, than that of the rectum ; but M. Milne-Edwards and Van Beneden consider that it follows in its displacement the organs of generation rather than the mouth. The heart in the Tunicata is never traversed by the rectum, as in other Acephala.\nIn the Ascidians the form of the heart is oblong, and thin at the two ends, or more or less tubular. Its substance is contractile, but extremely thin and transparent, so that it is scarcely distinguishable in the cavity of its highly pellucid pericardium. Cuvier observed that, in the species in which the branchial sac is bent upwards, he was not able clearly to discern a dilatation sufficiently marked to deserve the name of a heart, and was inclined to think that possibly in this case the heart\u2019s function was performed by the artery. Here, however, we may notice that specimens preserved in spirit generally afford but very indistinct traces of this organ ; and Cuvier does not appear to have had the opportunity of studying transparent specimens of the living animal, in which the heart can be detected by its pulsating movements.\nIn Ascidia intestinalis the heart, which is very long, and extended under the ventral border of the respiratory sac, communicates with the great thoracic sinus by a longitudinal slit situated at a little distance from its anterior extremity ; and when the peristaltic movements of the heart advance from behind forwards nearly all the blood contained in its cavity passes into this sinus, penetrating the vascular network of the branchial sac, and passing into the dorsal sinus, whence it is spread amongst the viscera, and returns to the posterior extremity of the heart not far from the anus. During this time the heart consequently performs the functions of a branchial ventricle, and the great thoracic","page":1206},{"file":"p1207.txt","language":"en","ocr_en":"1207\nT UNICAT A.\nsinus is a kind of pulmonary artery. But when this state of things has lasted some minutes, the direction of the peristaltic movement of the heart is inverted, and the blood, instead of traversing the branchial network from below upwards as previously, moves from above downwards, and passes from the great thoracic sinus into the heart. The latter is then an aortic ventricle, and the sinus a branchial vein or aortic auricle. In a very fresh and uninjured individual, of Cynthia ampulla, Van Beneden counted 45 contractions in one direction ; and then, after a rest during the space of two pulsations, he counted 160 to 170 in the other, the pulsations being about 70 per minute.\nIn injecting the vascular system of the simple Ascidians, M. Delle Chiaje thought he found certain valvules so disposed as to hinder the return of the blood from the aorta into the cavity of the heart, or from passing again from the heart into the vessels through which it had arrived there. But by careful observations on living specimens, both Milne Edwards and Van Beneden have established the fact, that, as in the Botryllidce, the Salpid\u0153, and the other Ascidian families, the blood of the Ascidiad\u00e6, after having flowed for some time in one direction, traverses the same circle in an opposite direction; a condition that would be impossible were any valvular hindrances to return currents of the blood present.\nIn Chelyosoma*, the heart is very distinctly seen in the animal when dissected ; it lies near the oesophagus, and has two distinct chambers. The aorta rising from its anterior part is a stoutish vessel, and at first lies close to the intestine : it afterwards runs in the space within the intestinal loop, ultimately breaking up into largish branches, distributed on every side. The ramifications divide some 4 or 5 times, and terminate somewhat abruptly, the extremities appearing as if closed. Throughout the surrounding generative organs there is a very fine network of vessels, but whether they are arteries, veins, or gland-ducts is undecided. A largish vessel running along the left side of the stomach and duodenum appears to return the blood to the branchial sac.\nMr. MacLeay describes the heart of Cys-tingia as being large, ovoidal, and of a lobular appearance ; and having four vertical, lateral openings, capable of considerable dilatation.\nIn Cynthia ampulla the heart is placed a little within the great intestinal loop, and near the middle of the body : it is fixed on an oblong vesicle, enclosing calcareous concretions. This vesicle is situated exterior to and above the first or principal bend of the intestine. Its colour is a greenish yellow, and it has apparently no aperture, or communication with other organs. The heart itself is a slightly bent tube, with very elastic walls ; it has two openings; a single large aperture on one part, and opposite to it three ves-\n* Described by Escliricht (Royal Danish Trans, vol. ix. p. 12.), to whom we are indebted for much valuable information, both with respect to this genus and the Salpians.\nsels that carry off the blood in different directions.*\n\u201c The circulation of the Ascidians,\u201d says Van Beneden, \u201c differs but little from that of the Bryozoa; and is transitional between that of the Polypes and of the Molluscs. If we remove the heart of the Ascidian, the disposition of parts is very similar, and the simplification of an apparatus cannot more visibly take place. The Ascidia is but a digestive canal suspended in the midst of external membranes, with a liquid moving in the peri-intestinal space. A colourless liquid (blood) occupies this cavity ; but it is only in the branchial network and tentacles that it can be said to be contained in vessels. All around the intestinal tube this fluid is alternately moved from right to left, and vice versa. In the vessels composing the vascular network, and in the respiratory tentacles, the same movement of the nutrient fluid takes place. This blood contains somewhat regular globules, white as the containing liquid, that indicate the course of the fluid. In some individuals the blood is yellowish. M. Milne-Edwards has observed* an Ascidia with red blood.\u201df Mr. Lister observed that in a sessile Ascidian half an inch long, the blood-globules were about the same size as those of the minute Perophora, viz. from \u201800025 to \u20180002 inch in diameter.\nVan Beneden, to whom we are indebted for so much information with regard to simple Ascidians in general and Cynthia ampulla in particular, has observed in living specimens of this species, that the blood is distributed to each branchial trunk at the same time, and with the same direction, ascending and descending alternately. According to this, the heart, contracting in one direction, sends blood towards the branchiae, filling all the vessels at one time, and recalls it by contracting in an opposite direction. That a series of contractions in one direction, during a certain time, may take place without engorgement, there must be a direct communication between the branchiae and the peri-intestinal cavity; and this is afforded, according to Van Beneden, by the respiratory tentacles, see p. 1202.\nSeen under the microscope, the contractile tissue of the heart affords no trace of muscular fibre. The contractility remains some time after the removal of this organ from the body ; and that without being irritated.\nNervous system. \u2014 A single ganglion, oval, soft, consisting of a saclike neurilemma, enclosing nerve-cells or neurine, placed in the substance of the mantle, and between its two tubular orifices, gives off four branches, two of the branches forming a loop around either tube, and other lesser filaments distributed about\n* In the Physiological Series of the Hunterian Museum there is a highly illustrative dissection of A tuberculata (No. 898. B.), prepared by Prof. Owen, that beautifully exhibits the heart and its pericardium, the branchial vessels, partially injected, and other organs.\nf Recherches Zoologiques faites pendant un Vo vage en Sicile. Comptes Rendus, 23 Nov. 1841.\n4 h 4","page":1207},{"file":"p1208.txt","language":"en","ocr_en":"1208\nTUNICAT\u00c2.\nthe mantle. Besides these, Meckel* found in the Ascidia gelatinosa one larger and two smaller ganglia between the stomach and the branchial sac. Cuvier considered the large ganglion to be the analogue of the \u201c inferior \u201d ganglion of Molluscs, found in the Bivalves between the branchiae and towards the origin of the tube that admits the water ; and observed that he had not seen any nerves terminating at a brain, nor the brain itself, which must be situated by the mouth at the base of the branchiae.\nThe great nerve-ganglion in Chelyosoma, long and \\\"f broad, cylindrical, and yellow-coloured, lies near the middle of the inferior surface of the plated test, and a little to the left (fig. 777. f). From its anterior angle it sends four branches, two of which form a halfcircle around the star-shaped muscular apparatus of the branchial orifice, the other two losing themselves in the muscles bordering the nearest plates. From the posterior angle arise eight nerves, four going to the anal orifice, and four to the lateral muscles of the plates (fig. 777. d, g).\nSpecial senses. \u2014 In the last-named genus there are two remarkable bodies found in connection with the nerve-ganglion, which Professor Eschricht, to whom we are indebted for a careful anatomical description of Chelyosoma, considers probably to appertain to the function of hearing (fig. 777. g, h). One of these bodies has the appearance of a minute bladder, filled with a whitish substance. It measures V\" long, and ' broad, and lies to the left of, and quite close to, the ganglion, being at its posterior extremity strongly adherent to it, or to the base of one of the nerves proceeding from it, by means of a stalk-like attachment. Through its diaphanous walls a row of arched transverse striae are discernible, which are either folds of the parietes, or a partition. The other body is pear-shaped, about long, lying anterior to the ganglion and the little bladder-like body, and, like them, between the serous membrane and the respiratory sac ; its stem is placed between these two bodies, and its head advances up to the hindmost muscle of the branchial orifice. It seems to be of tolerably firm consistence, but it is not at all bony or horny. Its thick, anterior portion is barely broad, and has anteriorly a deep hole, which seems to lead into a large cavity ; the border on all sides of this pit is prominent, gently declining to a blackish little body within.\nThe Ascidice have frequently around the extremity of each process of the mantle, i.e. the branchial and anal tubes, a row of coloured points or ocelli, similar to the imperfect organs of sight present in the majority of the bivalve Acephalans, where they are arranged along the margin of the mantle, or dotting the edges of the siphonal orifices. The number of these oculiform points correspond with the number of processes or folds that the margins of the tubes respectively bear ; about eight in the\nbranchial, and six in the anal tube. They are usually red, as in A.vitrea, A. virginea, A. pru-num, and others; in A. mentula they are yellow, with a central red spot.\nM. Milne-Edwards has observed similar eyelike points around the oral tubes of Amaurou-cium and Parascidia, belonging to the botryl-lian group of Tunicates.\nSome of the Salp\u00e6 also have ocular spots.\nBesides these oculiform points in the adult animals, Van Beneden has observed in the larvae of Cynthia ampulla, on the side of the gibbous or anterior portion representing the head, some black points that he regards as true eyes. Speaking of the development of the young Ascidian in the egg, Van Beneden describes the separation of the contents of the incubated ovum into an external layer, to form the skin and the tail of the young animal, and a second layer, of which subsequently the walls of the alimentary canal are formed ; and, thirdly, an internal vitelline mass. \u201c In the thickness of the external layer,\u201d says Van Beneden, \u201c there appears towards the middle of the body, and rather inferiorly, a cell filled with black pigment, which must be regarded as the organ of vision. It persists during the whole term of the animal\u2019s locomotive existence, and disappears after it becomes fixed. These organs,\u201d he adds, \u201c which we may well call eyes, although so simple, are constant ; sometimes two are discernible on one side.\u201d\nM. Milne-Edwards has also seen in the larvae of the compound Ascidians one or two blackish points, but towards the posterior extremity of the body ; he merely notices them, without assigning for them any function. \u201cWe consider ourselves,\u201d says Van Beneden, \u201c sufficiently authorised, by all that we have seen in the embryos of the free inferior animals, to elevate these pigment-cells to the dignity of an organ of special sense. To say that the presence of an eye implies that of an optic nerve and of a brain does not appear to us to be more just than to say that there are muscles when there is movement. We have the example of the Hydrce, that, without muscles, without nerves, without brain, and without a special organ of feeling, are sensible to light, and avoid or approach at will bodies whereby they are affected. And if the Hydra, without special apparatus, is sensible to light, we do not see why a cell of pigment may not be the first rudiment of the organ of sight. The appearance of the eye and the ear, in the animal series, takes place in similarly simple rudimentary forms.\u201d *\nGeneration. \u2014 The Asddiad\u0153 are all hermaphrodites. Between the fold of the intestine, and close to the liver, when the latter exists, there is observed a whitish glandular organ; this is the ovary. An undulatory duct passes from it, which, following the rectum, opens near its extremity into the cloaca. Opposite to the opening of the oviduct, Carus noticed the orifice of another glandular organ, which he thought to be either a male organ, or serving\nSchalk, De Ascidiarum Structura, Halle, 1814.\n* Van Beneden, M\u00e9m. Brux. Acad. vol. xx. p. 40.","page":1208},{"file":"p1209.txt","language":"en","ocr_en":"1209\nTUNICATA.\nto furnish the gelatinous covering of the ova.\nThe ova of Ascidies, instead of passing from the ovary to the branchiae, there to be developed as in a uterus, are emitted externally, by the oviduct conveying them into the cloacal cavity, whence they are carried outwardly by the current of water through the external anal aperture, or through the communicating lateral opening into the branchial sac, and thence through the branchial aperture. Cuvier says that he found some minute egg-like bodies between the branchial sac and the mantle; a position very analogous to that held by the ova of the bivalve Molluscs ; and fee thought it probable that ova so placed were fecundated by seminal fluid emitted by the same duct that leads from the ovary. These granules, however, M. Savigny apparently regards as little glands.\nThe generative organs are sometimes single and sometimes double ; in the latter case, the two halves, right and left, are completely separate, as in other Acephalans, and emit their products separately into the cloaca, which serves as a kind of incubational or marsupial pouch.\nThe ovary is single in Pkallusia, Pandocia, and Dendrodoa ; it is usually double in Pol-tenia, See. In Cynthia the ovary is either single or multiple, sometimes very large, forming long groups of clustered globules, each globule being crowded with ova.\nThe single ovary is sometimes enclosed within the intestinal loop, without adhering to it, and sometimes, as in C. papil/ata, &c., it lies against, and is adherent to, the rectum. In C. papWata the ovary is bent on itself and terminates by an oviduct at each end. In C. eanopus there are 2\u20144? or more ovaries ; those on the right side are placed against the rectum, and all terminate, as usual, by oviducts. In C. microcosmus there are two ovaries on the left side. They are composed of separate gelatinous lobes, having the appearance of a bunch of grapes. In C. mytiligera the ovary has the form of a membranous pouch, which furnishes points of attachment to the exterior of the branchial sac, and is fixed to the mantle and to the inner part of the intestinal loop. Its duct is very thin, and follows the usual course by the side of the rectum. In C. polycarpa and C. pomaria, Savigny describes certain numerous hemispherical or conical bodies adhering to the mantle, almost fifty in number, and disposed in rows, somewhat cor-responding to the six branchial folds, as being possibly the ovaries of these species. These bodies are without ducts ; they are formed of a mass of granules resembling the eggs of some other Ascidians ; they are much compressed, and resemble a compound berry held in a 5-fid cup ; they have apparently no communication with each other or externally, and are accompanied at their base with gelatinous, transparent, subpedunculated vesicles, apparently empty. In C. papi/lata, which has other generative organs, there are many rows of isolated, gelatinous, semitransparent, wrinkled\nvesicles, corresponding to the arrangement of the branchial folds, attached to the mantle, and receiving bloodvessels from it. The lobes of the ovary in C. microcosmus, after the emission of the eggs, wither into wrinkled vesicles closely resembling these sessile vesicles in C. papillata. Certain soft bodies observed in C. microcosmus, and somewhat similar to the above, Cuvier regarded as fat, serving as stores of nutritive matter ; but with this Savigny cannot agree. Savigny also points out the occurrence of various irregular, but somewhat similar fungous or fleshy excrescences on the mantle (fig. 39. i,l, Vol. I. p. 112.), ovaries, and intestines, sometimes even quite investing the latter ; but these are quite distinct from the ovary-like bodies above described.\nIn Boltenia reniformis the ovaries are double, unequal in size, elongate, formed of coarse subcubical lobes, situated one on each side of the body, and directed towards the anal orifice ; the right or smaller ovary, straight, claviform, fitting closely into the ascending loop formed by the stomach and intestine. The left ovary, larger and less lobulated, is on the opposite side, between the mantle and the branchial sac ; it is undulating, and extends downwards behind the branchial vein. The tissue of these ovaries is a yellowish membrane of distinctly cellular structure, containing groups of large opaque ova and smaller clusters of exceedingly minute diaphanous granules. The ovaries of Cystingia are two free racemes composed of globular bodies, as in Cyntlii\u0153, arranged on the two sides of the body with the branchial sac and stomach between them. In Dendrodoa (fig. 778. /c) the ovary is single and branched, consisting of a trifurcate, cylindrical stem, bearing at its base on one side a forked branch, and on the other a simple one, all of the same thickness ; it is situated on the left side of the body between the mantle and the branchial sac. In Chelyosoma, Professor Eschricht describes as an ovary two darkish bodies, filled with vascular ramifications ; placed, one between the liver and the rectum, and the other around the fold of the intestine. Another somewhat similar organ, traversed by ramifying vessels, and placed at the anterior extremity of the body, is apparently the testicle. Connected with this organ, a distinct sigmoid duct runs to the right posterior angle of the body, from whence a filamentous tube passes along to the left posterior corner.* In Cynthia ampulla the generative organs are situated in the intestinal fold, and appear at first sight to form a single organ ; but by the aid of the microscope two distinct organs, male and female, are easily recognised (fig. 779. a). The testicle forms a sort of framework around the ovary ; it is of a milky white colour, and is composed of an infinite number of short, twisted c\u0153ca, visible to the naked eye, and somewhat analogous to the seminiferous canals composing the testicles of higher animals. Three or four mammillary processes rise from the anterior\n* Royal Danish Transact; vol. ix. p. 13.","page":1209},{"file":"p1210.txt","language":"en","ocr_en":"1210\tTUNIC AT A.\nsurface of this organ : they are hollow in the centre, and emit a milky fluid, which is shed\nFig. 779.\nA,\tgenerative organs of Cynthia ampulla, situated \u2019 in the fold of the intestine. {After Van Beneden.)\na, stomach and its aperture (destitute of oesophagus) ; b, rectum and anus ; c, ovary, with its outlet into the cloaca; d, testicle, enveloping the edges of the ovary.\nB,\tmagnified portion of the reproductive organs of Ascidia grossularia. {After Van Beneden. )\na, testicle ; b, ovary and ova.\ninto the cloaca, and contains, or rather.is almost composed of, spermatozoa, with disciform heads and filamentous tails. The ovary is blackish, and is situated in the midst of the testicle. Its situation corresponds to that of the ovary of the Limaces among the Gasteropods, which is surrounded by the liver. It is easily distinguished from the testicle by its colour and by the appearance of its contained eggs. The oviduct opens into the cloaca by the side of the anus. In Ascidia grossularia the eggs, seen through the walls of the ovary, are of a fine red colour, and are contained in separate sacs, the ovary appearing like a bunch of grapes {fig. 779. b). Van Beneden has distinctly seen in all of these ova the two germinal vesicles. The vitellus is at first white, but during development it becomes of a deep red. By the side of the ovary is another series of sacs without ova, and some free cells containing a great number of other more minute cells moving about in their interior, and which when shed swarm about like spermatozoa. These appear to constitute the male organ, and its disposition accords with that of the Amaroucium argus, and with that of the Bryozoa (Van Beneden).\nThere remains much to be elucidated with regard to the generative functions of the Asci-dians. The male and female organs are always associated together, and are apparently each provided with efferent ducts. It appears, however, doubtful whether or not occasionally the ova and the spermatozoa may not be brought into contact either in the organs themselves or in the ducts, as well as in the cloaca. We may notice that the disposition of the sexual organs in the Bryozoa, to which in so many respects the Tunicata bear reference, appears to be, from Van Beneden\u2019s observations, as follows. A male and a female organ are separately developed in the peri-intestinal cavity. Each is formed of cells, and in\nthese cells are formed others, which become either vitellus or spermatozoa. When the latter cells are matured, the walls of the exterior or mother-cells are burst, and their contents are shed into the fluid filling the cavity around the intestine. It is here the male and female elements come into contact, and the ova are subsequently discharged by an orifice at the side of the anus.\nIn some compound Ascidians the pedunclelike post-abdomen forms a receptacle for the ova ; and so does the pedicle of Clavel-lina, as in Cirrhipeds ; but the pedicle of Boltenia and similar forms does not appear to be used for that purpose.\nMuscular system. \u2014 The Ascidiad\u0153 being fixed in their adult state, have no muscles of general locomotion ; but they have numerous muscular bands by which they can effect certain movements of contraction and extension. The muscles do not consist, as in Bryozoa, of isolated fibres folding themselves irregularly during contraction ; but each muscle is composed of many fibres united. They make their appearance in the young individuals contemporaneously with the appearance of the respiratory sac. The muscular fibre of Tunicata, like that of the whole of the Acephala, is of the organic or unstriped type.\nIn the Ascidiad\u0153, as in other Tunicates, the muscular tissue is chiefly developed in the mantle ; the muscles of the heart and in-tesinal canal (if present) have not been observed. The muscles of the mantle are very thin and narrow bands, generally at considerable distances from one another, surrounding all the body of the animal from the anterior to the posterior extremity, and uniting in part with one another on the median line of the dorsal walls {fig. 780.).\nFig. 780.\nMuscular sac or mantle of Boltenia renformis. {Original.')\nIn Ascidi\u0153 the mantle is more muscular on the anterior and largest part, and more membranous posteriorly. Externally there is a layer of longitudinal muscular bands, and internally of transverse bands. In some","page":1210},{"file":"p1211.txt","language":"en","ocr_en":"TUNIC ATA.\t1211\n(A. intestinalis, &c.) the exterior layer is much the thickest, and is composed of about twelve distinct fascicles, the fibres of which are somewhat separated from one another, insensibly disappearing on the anterior and superior borders. In others (Cynthia microcosmus, &c.), this external layer is very slight, and formed of distinct fibres, whilst the internal fibres are stronger, transversely oblique, and interlacing. Circular bands of muscles generally surround the tube of each orifice, and are rather stronger towards its base. The fibres forming these collars of the two tubes occasionally interlace with each other at the interval between the tubes, in a figure-of-eight pattern. Sometimes these muscular collars or sphincters are very indistinct, and not so apparent as another set of fascicles, which run in a diagonally transverse direction across the sac, and pass up the sides of the tubes, converging at the orifices. The latter bands diverge from the two orifices in two sets, which in part cross each other obliquely, and form an open network.\nIn Chelyosoma (flg.rirn.a,b') each of the six triangular valvules that surround either orifice is furnished with a fan-shaped set of muscular fibres, adhering at one end to the inner surface of the test, and at the other extremity to a small papillary process on the valvule. Besides this set of muscles, and within them, is another set which passes laterally from one papilla to another, forming a sphincter, the base of which is hexagonal. There are other strong subcutaneous muscular fibres passing from the edge of the upper part of the tunic to that of the lower, and also from the edge of each of the coriaceous plates forming the upper surface (c, c).\nBy the action of these muscles, the body or inner sac of the animal is transversely contracted and somewhat lengthened; the tubular processes also of the mantle are closed, and more or less retracted. When the animal is alarmed, the contraction takes place rapidly, causing the water contained in the respiratory and cloacal cavities to be ejected by one or other of the orifices to the height of even three feet.\nThere is considerable analogy between the muscular system of the Ascidi\u0153 and that of the Bryozoa. In the latter there are retractor muscles of the sheath and the intestinal tube ; and in the interior of the cells there exist also transverse oblique cords, traversing the peri-intestinal cavity, and attached to one or the other surface of the skin. These transverse muscles contribute to open the tentacular circlet; and in the Ascidice,by their contraction, produce the jet that escapes from each of the two apertures.\nEmbryo-genesis of the Simple Ascidians.\u2014In examining under the microscope a portion of the ovary of a recent Ascidia, eggs in all stages of development may often be observed. In describing the various conditions and modifications of the ova of this family in course of development, we shall borrow largely from the careful and extensive researches given to the\nworld by Professor Van Beneden, to whom naturalists are so deeply indebted for much valuable information on the subject of the embryo-genesis of many of the Polypifera* and other groups of animals. The earliest form of the ovum is a simple vesicle; it next appears as a vesicle with an inner vesicle, which is evidently \u201cthe vesicle of Purkinje;\u201d and, thirdly, with a second, still smaller vesicle, \u201c the vesicle of Wagner these latter vesicles, one within the other, being enveloped in the outer or vitelline membrane (fig. 781. a).\nThe space between the external membrane and Purkinje\u2019s vesicle is occupied by a substance, at first clear and probably fluid, but soon appearing granulated, constituting the vitellus. This yolk increases rapidly, soon occupying the whole ovum : at the periphery its granules or cells become organised (fig. 781. b), uniting among themselves, and forming a continuous sacciform membrane. The mode of growth of the vitellus is by new cells being formed in the interior of the large older cells, and subsequently producing others in their own interior. The growth of the whole ovum is evidently carried on by this process.\nThe whole surface of the vitellus soon afterwards becomes embossed, presenting a mulberry-like appearance (fig. 781. c). The germinal vesicles disappear. At the centre of each little mammilla of the surface a transparent vesicle becomes distinctly visible, and the whole appear like so many ova each with the vesicle of Purkinje. These mammill\u00e6 increase, and their peripheral substance rapidly becomes granulated, in a similar manner to the change that took place in the whole vitellus. The mammillated appearance is now soon lost from 4he growth of the granules, and the surface becomes uniform, the mammill\u00e6 of the periphery uniting into a membrane, which constitutes the blastoderm. According to Milne-Edwards, the blastoderm in the Botryllidce is formed at a determinate point only ; but in Cynthia ampulla (the species in which Van Beneden watched the modifications of the ovum) the latter observer feels assured that it is formed simultaneously all over the yolk, as in all the inferior animals. At this period a number of vesicles become somewhat regularly arranged over the exterior of the ovum, which by their union with one another form a new enveloping membrane. Beneath this membrane a space, occupied by fluid, soon becomes apparent. All over the exterior of this new membrane are distributed white, transparent vesicles, having much the appearance of oil globules. This envelope soon becomes more and more extended by the increase of the contained albuminous fluid, and a second membrane appears beneath it, on the surface of which also oil-like globules become apparent, as on the external membrane (fig. 781. o). The ovum is now composed of an external membrane, of a white\n* See Polypifera ; also Papers by Prof. Van Beneden on Campanularia, Tubularia, and Bryozoa, Mem. Brux. Acad. tom. xvii. xviii. and xix. \u201c","page":1211},{"file":"p1212.txt","language":"en","ocr_en":"1212\tTUNICATA.\nfluid layer, another thin transparent membrane, an organised layer forming the periphery of the vitellus, and lastly of the soft yolk in the centre, the vitelline membrane and the blastoderm forming one with the vitelline mass.\nThe external membrane and the albuminous layer beneath it appear to be formed externally to the ovum by the oviduct or the ovary; and as they envelop the ovum after its complete development, they may be considered only as accessory parts.\nIt being uncertain whether the ova in which these changes take place, have been subjected to fecundation whilst still in the ovary or oviduct, there arises the interesting question as to what extent of modification, even to the disappearance of Purkinje\u2019s vesicle, and the mulberry-like condition of the vitellus, can take place before the ovum has received the stimulus of the seminal element.\nDuring the changes of the ovum in this first period of its development, the colour of the egg is occasionally subject to certain modifications. In Ascidia grossularia, the ova become of a bright red colour, and in some species no change of colour takes place. In Amaroucium, a compound Ascidian, the ova change from a pale to a deep yellow.\nThe second period of development is marked by the prolongation of one side of the yolk to form the caudal appendage. The ovum has now a chorion, albumen, and yolk, the two latter being separated by a fine membrane. The vitelline or embryonic mass becomes contracted about its middle, and is somewhat bean-shaped. From this time there are observable two extremities, one lengthening itself, as the other becomes more and more globular; and respectively representing the caudal appendage and the body (Jig. 781. e).\nFig. 781.\nDevelopment of Cynthia ampulla. (After Van Beneden.')\nA, ovum, with the vesicles of Purkinje and Wagner, b, the same further advanced, with surrounding vitelline globules, c, the central vesicles have disappeared, owing to the development of the vitellus ; the ovum presents the appearance of an agglomeration of ova, or the mulberry-like aspect, d, further developed ovum, with double external membrane and intervening transparent liquid, e, the yolk elongated, partially divided in the middle ; the larger portion becoming the trunk, and the narrow portion the tail, of the larva, f, the embryo at the full tenu of incubation : a, anterior process ; b, eye ; c, integument. G, the same, further advanced ; the caudal portion entirely absorbed, leaving the tegumentary elongation empty; a, anterior process. H, the same, further advanced; superficial appendages still present ; internal organs more distinct, x, embryo nearly perfect ; a, branchial orifice with tentacles ; b, anal orifice; c, eye; d, oesophageal collar; e,(?) ; //, ciliated circles, rudiments of respiratory organs; g, g, g, muscular bands.\nThe former of these becomes more and more elongated, following the outline of, and folding itself around, the body, which is included in the ovum, as in many reptiles.\nIn Amaroucium, according to Milne-Ed-wards\u2019 observations, the tail is formed by the marginal portion of the yolk being condensed, at the same time that the body is flattened, and then separated from it throughout its length. Van Beneden. however, remarks, that in the simple Ascidians, as we have stated above, the tail is rather an elongation of one part of the yolk, and that, like the exterior organs of all other animals, it is formed by extension and not by division or separation.\nThe body part of the embryo has an internal cavity, and is formed of the yolk; it is surrounded by the membrane, which becomes the skin of the body and tail. The caudal appendage is hollow, and communicates with the central cavity ; it does not in Ascidi\u00e6 pre-\nsent the spiral or zigzag cavity observed in the\nBotryllid\u00e6.\nThere is soon formed within the embryo another layer distinct from the exterior, and which is destined to become the parietes of the intestinal tube. There exist then two layers, internal and external, from which all the organs are derived. In the thickness of the external layer, near the middle of the body, and rather superiorly, occurs a black pigmentcell, which Van Beneden regards as a rudimentary eye. In Amaroucium, Milne-Edwards has observed one or two blackish oculiform points towards the posterior extremity of the body.\nThe chorion is now ruptured, and the larval embryo appears with a pellucid membrane covering its body and tail (Jig. 781. f). This membrane has been already mentioned as investing the ovum at a late stage of the first period of its development, immediately after","page":1212},{"file":"p1213.txt","language":"en","ocr_en":"TUNICATA.\t1213\nthe vitellus lost its mulberry aspect, and when the albumen was formed. It closely envelopes the caudal appendage, and terminates beyond it by a tapering prolongation : subsequently it becomes the test of the animal. The larva, resembling in appearance a frog-tadpole, still remains a while in the cloacal pouch, but is soon carried out by the current leaving the animal : it is very active, wriggling about for hours. After a brisk locomotive existence for about twelve hours, the embryo fixes itself to a foreign body. The tail then begins to disappear, being slowly absorbed; its pellucid membrane remains entire for a little time, but is ultimately detached from the body. At the same time other appendages spring from the body, the principal one of which arises from the anterior extremity, elongates itself more and more, attains a trumpet-like shape, and may be considered as the future mouth {fig. 781. g). In Amaroudum, Milne-Edwards observed generally five appendages arising from the anterior extremity of the body, two of which soon disappear, and the threte others, which are persistent for a while, terminate in button-shaped, dilated suckers, touching the parietes of the external integument. In Cynthia ampulla other processes or appendages occur all over the body ; these are somewhat similar to the anterior appendage, but are never constant, either in direction or number; one specimen had seven appendages on one side. Sometimes the numerous appendages resemble tentacles, giving the embryos the appearance of young Tubulance.\nThese processes are hollow, communicating with the central cavity. None of them appear to open externally, or to be at all like suckers; and a considerable space frequently exists between them and the enveloping membrane.\nThe young animals are attached to solid bodies by this external tunic, on a different side to that at which the orifices make their appearance. \u201c If,\u201d says Van Beneden, \u201c the appendages served as suckers for attachment, the animals would have the mouth on the side by which they are attached.\u201d\nIt is at this stage of growth that the walls of the internal cavity are distinctly seen through the external membranes. The contents of the digestive tube are seen to consist of a rather opaque mass, distinct from the surrounding clear space.\nAs soon as the animal is fixed, the transparent membrane that has remained floating since the absorption of the caudal appendage, is completely detached, and the integument and the test begin to be formed.\nIn the third period of development the embryo takes on the ascidian character. The development of the internal organs progresses, and the external orifices become apparent {fig. 781. h). At the commencement of this period, the form of the young Ascidian varies considerably. The numerous appendages disappear, just as the caudal appendage was lost. The embryo becomes rounded and larger, and its substance is distinctly seen to be disposed\nin three layers. Up to the present time the vitelline cavity has had no external communication, but the mucous cavity is now extended on one side, to form the mouth. The mucous layer is elongated also on the opposite side, but instead of reaching the exterior, it is folded back on itself, forming the intestinal loop. The yolk soon opens a passage on each side, constituting the oral or branchial, and the ventral or anal, orifices. The intestinal tube becomes completed by its separation into the respiratory, the digestive, and the cloacal cavities. Around each external orifice certain nipple-like, palpiform bodies appear, which soon lengthen, but before long they are hidden by the integument {fig. 781. i). The eye-like pigmentary spot still continues for some little time, and is situated in the middle of a band (the oesophageal collar) that seems to embrace the respiratory cavity. At the base of the intestinal cavity, the opaque concretionary body appears, to which the heart is subsequently attached, and which Van Beneden considers to be analogous to the internal shell of the Limaces. This is furnished with vibratile cilia, which occasion circulatory currents, until the heart makes its appearance in the form of a thin, gently pulsating, membranous body. Contemporaneously with these cilia, others appear in the interior of the branchial sac, in the form of a ciliatedj'circlet, to which a second and afterwards others are added, forming altogether the peculiar branchial tissue. These cilia give rise to currents in the digestive and subcutaneous cavities. The young Ascidian can now carry on the functions of respiration and digestion.\nAt the surface of the skin, and around the anal and branchial cavities there are apparent longitudinal striae, which are evidently the rudimentary muscular bands. The sphincters, also, at the two extremities of the intestinal tube, are brought into action. Some slight further modifications only are now required to perfect the development of the little Ascidia.\nAnatomy of Clavellinid\u00e6.\u2014 Clavellina. \u2014 At the superior extremity is the buccal orifice, which is circular, looking directly upwards {fig. 768. c), and furnished with a very thin, prominent, cylindrical margin ; to the interior of which is attached a ring or circlet of simple tentacular filaments, about thirty in number, of which about ten are long enough to reach to the centre of the cavity of the tube, whilst the others are very short, and situated between the first. Near this first orifice, and toward the superior part of the dorsal aspect of the thorax, is the second or anal orifice, which is also circular, with an entire rim. The external tunic or tegumentary membrane (test) of the body is thin, but subcartilaginous. It adheres feebly to the other parts, except around the two orifices. At its base, or inferior extremity, there are a variable number of radici-form prolongations, which serve to fix the animal, and some of which often bear at intervals little pyriform tubercles, which become developed into new individuals.","page":1213},{"file":"p1214.txt","language":"en","ocr_en":"121\nTUNICATA.\nThe test is so transparent and colourless, that the interior structure of the animal may be easily studied without having recourse to dissection. There is observable, however, certain yellowish lines traversing the transparent test, which have a granular appearance, and correspond, according to M. Milne-Ed-wards, to the lines of junction of certain parts of the interior. Two of these bands descend vertically, very near one another, throughout the medial line of the ventral surface of the thorax, and are separated by a linear, colourless, semi-opaque space. A third line rises on the right and left of the test, at the superior part of the thorax, and is directed horizontally backwards, describing a circle around the base of the oral orifice. A fourth line, also annular, encircles the inferior extremity of the thorax. A fifth surrounds the anal orifice, and is prolonged upwards and forwards, almost to the posterior margin of the oral orifice. There is generally a sixth line, much paler than the others, and more deeply situated, at some distance from the dorsal surface of the thorax, descending vertically from the superior to the inferior ring.\nTowards the middle of the abdominal portion of the body the stomach appears, as a small, orange-yellow, oval mass, bearing four yellow vertical lines, like those of the thorax. Lastly, close to the stomach, is another orange-coloured spot, formed by a coloured portion of the intestine, and, still lower, the whitish gland-like mass, comprising the generative organs (fig. 768. p).\nThe mantle is suspended within the first tunic ; it is membranous and extremely delicate. Superiorly it is attached around the two orifices, and inferiorly it terminates in a cul-de-sac. It often presents inferiorly some tubular prolongations, sometimes simple, sometimes ramified ; which descend towards the base of the animal, and sometimes project into the interior of the root-like processes of the external tunic. Its surface is traversed with divers muscular fibres, some of which are \\ circular, and constitute the sphincters around the mouth and anus ; whilst others, to the number of nine or ten pairs, arise from a kind of tendinous collar surrounding the mouth, and descend vertically to the inferior extremity of the abdomen. These last muscles serve to shorten or bend the body, and it would appear that it is by the elasticity of the external tunic that they are lengthened again, after having been so contracted, for there do not appear to be any traces of transverse muscular fibres proper to act as antagonists to the vertical fibres.\nIn all the thoracic portion of the body a third tunic is present. This, like the preceding, is membranous, and is suspended in a kind of sac formed by the latter ; it adheres to it by the rim of the anal orifice and along the collar around the base of the mouth. Inferiorly this membranous pouch is united in its extent to the two orifices of the digestive canal, where for the most part it is continuous with the wall of that tube. Its cavity\nconstitutes the thoracic chamber. It encloses' the branchial organs, and presents on the dorsal side a free space, which forms a kind of cloaca, ending at the anal orifice of the external tunic. Along the medio-ventral line a vertical groove is observable, and at the point where it adheres to the second tunic, between the mouth and the anus, we can perceive a minute tubercle, which is the nervous ganglion. This thoracic chamber exactly resembles the great cavity of the Salpians, and would scarcely differ at all, if the cloaca were shorter, and the anal orifice more distant from the mouth, and directed backwards.\nThe branchiae (fig. 768. e) exist as a large membranous band, arising from the dorsal surface of the thoracic cavity, below the gangliform tubercle, and by its opposite extremity fixed to the space situated between the oesophageal orifice and the termination of the intestine, thus separating the cloacal from the great pharyngeal or respiratory cavity ; only, in place of presenting on eaeh side simple striae furnished with vibratile cilia, as in the Salpians, this kind of vertical body bears right and left a series of filiform appendages, directed horizontally towards the ventral side of the respiratory cavity, where they are fixed on each side of the middle sulcus, and, during their passage across, are united together by a number of other slender vertical filaments. From this disposition of the parts there results a kind of trellis-work, which fills up all the pharyngeal portion of the branchial chamber, permitting no communication between the latter and the cloaca, except through the meshes of its network, which are bordered all around with vibratile cilia. This complicated branchial apparatus adheres also to the thoracic tunic by its two extremities. The dorsal column, which thus forms the base of the branchial organ, and which represents the simple bran-chia of the Salpians, is considerably prominent in the interior of the respiratory cavity, and exhibits along its ventral margin a series of ten membranous languets, which are usually straight, and are apparently susceptible of a kind of erection. The interior of this membranous band is occupied by a large vascular cavity, which M. Milne Edwards terms the branchial or dorsal sinus. The transverse little fillets which spring therefrom are in number about twelve pairs, and the vertical filaments that unite the latter are nearly of the same size: these are about thirty in a rank, and there are thirteen ranks, viz. eleven situated between the two transverse fillets, and two which stretch from the first and second fillets to the wall of the thoracic chamber, and are fixed along the two yellow lines, placed as rings at the two extremities of that chamber. Some membranous processes appear also to stretch from different points of the surface of the branchial net-work to the walls of the cavity in which the latter is suspended ; but these are few, and do not hinder the eggs, deposited in the cloaca, from insinuating themselves frequently into that portion of the cavity situated on each side of the respiratory","page":1214},{"file":"p1215.txt","language":"en","ocr_en":"TUNICATA.\t1215\nsac. The spaces circumscribed by the narrow elongated meshes, supported by the vertical filaments, and bordered with vibratile cilia, are not occupied by a membrane, but form openings, somewhat like a button-hole, called branchial stigmata. These chinks or spiracles, through which the water passes from the branchial sac in the thoracic chamber to escape outwards by the anal orifice, are consequently disposed in the same manner as the vertical filaments that circumscribe them, that is, parallel to each other and in transverse ranks, thirteen in number. Lastly, each of these vertical filaments is perforated by a canal, opening by its two extremities in other similar but larger canals, that occupy the interior of the transverse fillets. The latter vessels in their turn empty themselves by one of their extremities into the great dorsal or branchial sinus, and by the opposite extremity into the vertical fold of the ventral wall of the thoracic chambers, which is circumscribed by two parallel, vertical, yellow lines, and which places the respiratory organs in relation with the great thoracic sinus, lying between this chamber and the ventral portion of the internal tunic of the body. These two sinuses communicate also one with another by the vessels that surround the branchial orifice, and from which spring other vessels that descend towards the abdomen.\nThe pharyngeal portion of the thoracic chamber, tapestried with the branchial network, opens externally at its upper extremity, by the branchial aperture, which occupies nearly the whole of its diameter, and is furnished with a kind of radiating net-work of tentacular filaments. This cavity is cylindrical, and at its inferior extremity has a large transverse slit, the opening of the oesophagus, opposite to the external oral aperture. The oesophagus is large, and descends vertically into the abdomen terminating in the stomach {fig. 768. /), which is ovoid and swollen. The intestine{m) springs from the inferior extremity of the stomach, and at first running vertically downwards, and then bending forwards and upwards, so as to form a loop, it ascends towards the thorax by the side of the stomach and oesophagus, slightly covering them on the right side. Arrived at the superior part of the abdomen, it is again bent, passes by the side of the oesophagus, ascends rather behind the branchial sac, and terminates at the inferior part of the cloaca [n), at about the level of the antepenultimate row of the branchial stigmata. Throughout its length the intestine preserves nearly an equal calibre, but varies in its appearance, and is divisible into three portions.\nThe first part, the duodenum, succeeding to the stomach and forming the intestinal loop, is colourless and transparent. The next portion, placed on a level with the stomach, but on the ventral side of the body, is on the contrary of a dull-yellow colour, and the tissue of its walls has a glandular appearance. This M. Milne-Edwards considers to be the hepatic portion of the alimentary canal, and comparable to the organ known in insects as\nthe chylific ventricle. Lastly, in its third portion, the intestine again becomes membranous and colourless : here the f\u00e6cal matter is collected into brownish pellets, and from its functions and position this portion of the tube is termed the great intestine, or rectum.\nTo the right of the intestinal loop is placed a glandular mass, the chief part of which is formed by the ovary, recognised by its vesicles, and by the eggs of different degrees of development contained in it. Below the ovary is the testicle, a mass of whitish and ramifying filaments, spread out in some degree on the intestine. From this glandular mass arises a milk-white filiform canal, which ascends between the stomach and the intestine, passes on the left side of the oesophagus, and opens into the cloaca, near the orifice of the rectum. This canal contains a silvery white fluid, crowded with spermatozoa, and must be considered as a vas deferens. There being no other visible duct leading from the ovary, this canal perhaps serves also as an oviduct. The eggs are minute, circular, and of a greenish yellow colour.\nThe heart is situated at the inferior part of the abdomen, lying against the intestine and the ovary, to the right and in front of the former, at the posterior part of the cavity of the mantle, between the tunic and the intestine, and much resembles that of Ascidia intestinalis. It is enclosed in a membranous sac or pericardium, and is cylindrical in form ; its superior extremity is on a level with the centre of the stomach, and its lower extremity, turned up a little behind, passes sometimes a little beyond the intestinal loop.\nThe Perophora, first described by M. Lister in Phil. Transact. 1834, p. 378., as a \u201c small Ascidia,\u201d is parasitic on Conferv\u00e6, &c., and appears to the eye like minute lumps of pellucid jelly, with a spot of orange and grey. The group consists of several individuals, each having its own circulatory, respiratory, and digestive systems, but fixed on a pedicle that branches from a common creeping stem, and all are connected by a circulation that extends throughout. They are very transparent, and their interior is easily seen. The two orifices are very short tubes ; the branchial is at the summit, and the anal is a little lower down. The longest diameter from the peduncle to the space between the openings is about \"085 inch (seefig. 306. a and b, p. 623. Vol. I. Cilici). The test is subcartilaginous and tough, more pliable near the orifices. It is lined internally with the soft mantle, in which a ramifying circulation is very distinct. A great part of the interior is occupied by the branchial sac, which is subcylindrical, flattened at the sides, and has its axis vertical. It is united to the mantle above and behind ; the juncture, beginning in front of the oral opening, extends backwards on each side of it, and then downwards in two lines ; between these, along the middle of the back, is a vertical compound stripe. At the bottom, the branchial sac appears to be in contact with the mantle, but at its sides and front a vacant space is left between them, communicating","page":1215},{"file":"p1216.txt","language":"en","ocr_en":"12 IG\nTUN IC AT A.\nwith the anal orifice (seefig. 306. B,fi loc. cit.). The sac is more compressed towards its lower part ; and here are placed, externally to it, the heart on the left, and the stomach and the other viscera on the right side, the anus opening upwards into the cloaca. On its sides and front the sac is perforated by four rows of narrow, vertical, irregularly oval holes or spiracles, about sixteen in each row, placed at less than the diameter of one of them apart from each other. Through these the water, which flows constantly in at the mouth when its orifice is open, is apparently conveyed to the vacant space between the sac and the mantle, and it then escapes by the anal orifice. The branchial tissue is extremely thin between the stigmata, but their edges are thickened, and are lined with closely set cilia, which by their motion cause the current of water. When these are in full activity, the effect upon the eye is that of delicately toothed, oval wheels, revolving continually in a direction ascending on the right and descending on the left of each oval, as viewed from without ; but the cilia themselves are very much closer than the apparent teeth, and the illusion seems to be caused by a fanning motion made by them in regular and quick succession, producing the appearance of waves, and each wave answering to the apparent tooth. The spaces between the rows of spiracles are of much more substance than the intervals between the spiracles in a row ; filamentous processes are stretched from them across the side cavities, attaching the branchial sac to the mantle : these spaces also support finger-like processes, about eight in a row, that project nearly at right angles into the central cavity.\nThe large short tubes of the branchial and anal orifices have each five or six obscure marginal indentations, and can be drawn in and closed at the will of the animal. Within and at the bottom of the branchial tube are numerous, simple, tentacular filaments of different lengths. The particles drawn into the branchial sac by the current of water are seldom stopped by these tentacles, but lodge somewhere on the branchial net-work. A lively animalcule will sometimes disengage himself by struggling, and dart about in the cavity until he lodges on some other part ; or if a morsel is found unsuitable, it is ejected by the funnel\u2019s being closed, and the branchial sac suddenly contracted vertically. Mostly, however, whatever part the food lodges on, it travels from thence horizontally with a steady slow course towards the front of the cavity, where it reaches a downward stream of similar materials ; and they proceed together, receiving accessions from both sides, and enter at last, at the bottom, the oesophagus; which is a small flattened tube, carrying them, without any effort of swallowing, towards the stomach : the oesophagus takes a sharp curve upwards and backwards before arriving there. \u201c It is extraordinary,\u201d observes Mr. Lister, \u201c that the particles pass along so near to the spiracles, with their cilia in full activity, without being at all affected by them.\u201d \u201c I have,\nsays he, \u201c in some positions, seemed to catch a glimpse of a membrane suspended within, too transparent to be commonly seen. One may imagine the water to pass to the spiracles strained through the meshes of such a membrane, and the food to be carried along it by invisible villi ; but this is mere conjecture.\u201d\nThe stomach runs backward horizontally. When seen from the side, its anterior portion has an inflated appearance, and, when from below, it seems to possess two lateral lobes. The liver has an ochreous tint, and envelopes the anterior portion of the stomach. The intestine on leaving the stomach rises, and then bends forward with a sigmoid flexure, and terminates in an ascending rectum and sphincter.\nTransparent vessels ramify along a part of the intestine, and meet at a collection of globular bodies, from whence, in one individual, two flattish lobes were observed to extend backwards. These globular and lobate bodies probably constitute the generative organs. From the meeting of the above-mentioned vessels two branches run ; one downwards and backwards, but under the stomach, the other forwards. From their direction Mr. Lister supposed them to communicate with a main stream of blood near the heart.\nThe circulation in these animals is very interesting, and easily discerned through their transparent tissues. The blood circulating in one individual of the group descends by the peduncle into the common root-like stem, and penetrates into the next member of the group, so that there exists in these Ascidians a common circulation, having as many centres and motive organs as there are animals growing on the same stem. The blood-globules are very numerous, and though not uniform in size or shape, are mostly between *00025 and \u20220002 inch in diameter, and approaching to globular. They are easily measured, as in the intervals between the stigmata they pass mostly but one at a time. The creeping tube, which unites the individuals of a group, contains two channels for two separate currents of blood, an upward and a downward one, that are flowing at the same time, and that send off each a branch to every peduncle. The blood then passes into the animal by one current, while another carries it back. One of these canals communicates, at the termination of the peduncle, with the heart, which is placed, as before mentioned, near the bottom of the branchial sac on the left side, and consists of a transparent ventricle or tube, running forward and a little downward, in a channel hollowed to contain it. Along the whole length of this tube, a part on one side of its axis seems fixed to the channel, the rest is free and contractile. Mr. Lister observed that when the blood entered the heart from the peduncle, contraction began at the middle of the ventricle, impelling onward the contents of the forepart ; and the contraction of the back part followed in the same direction, so as for the whole to have the effect of one pulsation. The heart was then filled again by a flow from the peduncle. The intervals","page":1216},{"file":"p1217.txt","language":"en","ocr_en":"TUNICATA.\t1217\nof the pulse were pretty regular in the same individual ; but in different ones they varied from two seconds to one and a half second. Part of the blood thus impelled formed a main upward stream along the front of the branchial organ, branching off at each of the horizontal passages between the rows of spiracles, and traversing the space above them on a line with the junction of the branchial sac and the mantle on each side. All these streams again united, and formed a downward current behind. The horizontal vessels were connected also by the smaller vertical channels between the spiracles ; the set of the current in the latter being upwards for the two lower rows, and downwards for the two upper rows.\nAnother large portion of the blood, on leaving the heart, immediately divided into many ramifications, that spread like a net-work over the stomach and intestines, and over the mantle. Of these, a part ran into the horizontal passages above the branchial sac, a part into the descending dorsal vessel. A large proportion, after leaving the intestines, took a short course, and collecting into one channel, flowed into the dorsal vessel near the bottom, and all, united, then entered the peduncle, and constituted the returning current that went to circulate in other animals of the group. After this circulation had gone on for a while, the pulsations became fainter for a few beats, and the flow slower, and suddenly, with but slight pause, the whole current was reversed, the heart gave the opposite impulse. The vessel in the peduncle that before poured in the blood, now carried it back, and the other channel the contrary, and every artery became a vein. These changes continued to succeed each other alternately. The average time of the currents being the same in both directions, but the period of each varying within a single observation as much as from thirty seconds to two minutes. Mr. Lister points out the analogy between this phenomenon and the very similar circulation that obtains in the stem of the Sertularia, described by him in the same volume of the Philosophical Transactions. This acute observer goes on to say, that sometimes, when the creeping tube, or the peduncle, has been injured, the circulation of an individual is in consequence insulated, but without appearing to impair any of its functions. In one animal which was severed from the peduncle, the pulsation ceased for a few seconds. It then began irregularly, and with considerable pauses, increasing in steadiness as it went on. At first the impulse given by the heart was towards the front ; and the downward back stream, instead of flowing out at the wound, was poured into the hinder end of the ventricle ; the cut end of the vessel leading from the heart being nearly opposed to the bleeding dorsal vessel cut through at the same place, and the two vessels, in their undisturbed state, lying across each other at this point. But when the current was reversed, part of the blood was driven for a time through the stump of the peduncle into the water ; however, it soon staunched, and all the vital VOL. IV.\nactions went on as before the separation, except that at the beginning of every pulsation there was a slight recoil.\nIn one case, where the circulation did not extend to another animal, one channel only was observed to be open in the peduncle, and in this a small current ran to and fro according to the direction of the impulse given by the heart. Some animals, which had probably been injured, but were still connected with other vigorous ones, seemed to be in course of absorption. One was observed in which the soft parts were so shrunk as to occupy a small part only of the tunic. The currents of its peduncle extended into this mass, but no heart or motion of branchiae was visible. Upon looking at the same the next day, the tunic was empty, the soft matter and the circulation reaching only to the end of the peduncle. Mr. Lister also once noticed a flux and reflux of the blood in a creeping stem, where the current did not communicate with any animal. In the buds sprouting from the stem, and destined to become new animals, the two streams of the stem run through the germ before its organs are developed.\nThe generation of the Clavellinidce takes place in two ways\u2014by ova and by buds. The genesis of the larvae of Clavellina from the ova is very similar to that of the larval Ascidi\u0153. The young of Perophora have not yet been observed. The method of the gemmiparous reproduction, according to the observations of Milne-Edwards, is as follows : Amongst the radiciform processes springing from the base of the test of Clavellina, and tending to preserve the animal in its position, are other filamentous prolongations which are hollow, and enclose a membranous tube, continuous with the internal tunic of the animal, and through which the circulation seen in the interior of the abdomen is also continued. This stolon-like body is closed at the free extremity ; it is at first simple, but as it lengthens, it becomes ramified ; and when its growth is further advanced, there are developed on the extremities of its branches, and even at different points along its length, tubercles, enclosing in their interior a minute organic mass connected with the interior tube. These tubercles rise vertically, and become elongate and claviform. The blood that circulates in the stem at first penetrates into the soft, pear-shaped, pedunculated mass occupying each of the tubercles ; but after a while these little germ-masses lose their peduncle and their attachment to the internal tunic of the principal canal, and participate no more in the circulation of the mother-animal. By further development they soon put on the ascidian character. The branchial sac is perfectly distinct, although not yet communicating with the exterior ; and the digestive tube bent loop-wise, below the thorax, is plainly discernible. Lastly, the oral orifice appears, and the general form of the young animal approaches more and more that of the adult. From this a new individual is then in like manner produced by stolon and bud, remaining attached\n4 i","page":1217},{"file":"p1218.txt","language":"en","ocr_en":"1218\tTUNICATA.\nto the mother by the former, and which at first has a circulation in common with the older animal, but soon enjoys an independent existence. The individuals either remain attached by the intermediate root-like prolongations, or become separate by the disunion of these slender filaments.\nIn one species of Clavellina, the bud-like bodies and young animals are produced not only on the root-like stolons, but also on the walls of the test itself {fig. 768. u, u').\nIn Perophora the growth of the buds is confined to the extremity of the creeping, rootlike tube, and the attachment of the individuals by the common root-stem is permanent through life, and not merely existent during the young state.\nAnatomy of the Botryllid\u00e6. \u2014 A description of the form and structure of the test of these compound Ascidians has been already given. The in- and out-lets of the aggregated individuals, as we have already seen, have either separate external openings, or the several vents of a \u201c system \u201d of animals unite to form one large common cloaca and external anal orifice.\nAll these external orifices are more or less irritable and contractile. When the little animals dilate their branchial orifice, a part of their body is raised so as to slightly emboss the general surface of the mass, and they protrude a membranous circlet or ring, the free border of which is cut into, generally six, regular lobes, but sometimes into eight. In Poly-clinum, the mouth is very contractile, and is surrounded by six little digitiform processes. Parascidia has eight of these tentaculiform bodies. Frequently, after death, as in Lepto-clinum, these orifices contract, and their borders sink in so as to be discerned with difficulty. In the interior of this orifice, and towards the base of the collar, a series of minute tentacular filaments can be perceived by the aid of a lens, which are directed, like the spokes of a wheel, towards the centre of the opening, or have a more or less curled appearance, in a similar manner to the tentacles occupying the same position in the simple Ascidians and in the Clavellinidce. The tentacles vary from four to twelve or more, but nine or ten is their usual number ; they differ materially in length, some being nearly rudimentary, whilst others, alternating with the first, are long enough to meet across the opening. In Amaroucium Nordmanni there are six long and six short tentacles within the branchial tube. In Botryllus smaragdus, in which the buccal orifice admits of considerable dilatation, a circlet of four longish filiform tentacles may be seen. The tentacles in B. aureus are more numerous than usual, but both in this species and in B. violaceus they are almost rudimentary. Diazona has fifteen or sixteen simple tentacles, and in Sigillina there are twelve.\nAround the base of the denticulated rim of the branchial orifice in Amaroucium argus {fig. 782.) there are seen four minute pinkish spots, which are probably rudimentary organs of\nsight. Similar, but more numerous, pigment-spots are observed in Leptoclinum Listen, Parascidia, and other genera.\nFig. 782.\nAnatomy of Amaroucium argus. {After Milne-\nEdwards.)\tAn isolated individual considerably\nmagnified.\nA, thorax ; b, superior abdomen ; c,post-abdomen ; a, proper tunic of the individual ; b, thoracic tunic ; V, longitudinal muscular fibres of the inner tunic ; c, branchial orifice ; d, branchial collar, below which are seen the oculiform points; e, branchial sac; f, thoracic sinus ; f, transverse vessels of the branchial sac ; h, cloaca ; i, anal orifice ; i', and appendage or languet; j, nerve-ganglion; k, oesophagus; l, stomach; m, intestine; n, anus, opening into the cloaca ; o, heart ; o', pericardium ; p, ovary ; p1, p\", ova, passing towards the cloaca ; q, testicle ; r, r', vas deferens, and its opening in the cloaca.\nThe separate anal orifices are frequently destitute of the crenulated or denticulated margin that surrounds the branchial tube. This condition has afforded a distinguishing character for some of the minor groups in Milne Edwards\u2019 classification of the Bo-tryllul\u0153. In Polyclinum, Amaroucium, Botryllus, and other genera, the anus, instead of opening directly outwards, empties itself into a common cloacal cavity, that belongs to a number of individuals, and is in the form of a large canal hollowed out of the common tegumentarv mass. This is frequently ramified interiorly, as in Botrylloides, and terminates at the opposite extremity by a simple","page":1218},{"file":"p1219.txt","language":"en","ocr_en":"1219\nTUNICATA.\nexcretory orifice, not occupying the centre of the \u201c system,\u201d but placed nearly at one of the extremities, and communicating with the individuals situated at the other end of the group by means of the interior canal.\nIn Amaroucium the f\u00e6cal or anal orifices, by which the common cloac\u00e6 open externally, are wide open during life, and easily perceived ; their form is round and their border thick ; but after death they contract, and are so much sunk in that they are demonstrated with difficulty.\nThe anal orifice in some genera is surmounted by a membranous languet, either simple or trifid (fig. 783. i').\nFig. 783.\nx m\nAnatomy of Botrylloides rotifera. (After Milne-\nEdwards.') Lateral view of an isolated individual\nmagnified.\nc, branchial orifice; e, branchial stigmata; /, thoracic sinus ; h, cloaca ; i, anal orifice ; i', supra-anal languet; j, nerve-ganglion-; k, oesophagus, l, stomach; m, first portion of intestine, or duodenum; m>, second portion, or chylific ventricle; m\", third portion, or rectum ; n, anus, opening into the cloaca ; q, testicle ; r, vas deferens ; t, radiciform appendage, or proliferous stolon ; t1, reproductive germs ; x, liver (?) ; x', its excretory duct.\nIn pointing out the natural groups of the associated Ascidians we have spoken of the division of the body into distinct portions, as the thorax, and super- and post-abdomen in Amaroucium {fig. 782.), and in Polyclimm, where they correspond to the three vertical chambers of the animal\u2019s cell ; and into the thorax and abdomen in Didemmm. The latter arrangement resembles that of the Cla-vellin\u0153 ; but in the Botryllians, on the other hand, no distinct separation is observable, the viscera being pushed up by the side of the branchial sac, as in the Perophor\u0153 and the simple Ascidians {fig. 783.). The thorax is generally more or less cylindrical, sometimes hemispherical {fig. 769.) or subglobose, and contains the branchial organs. In Botryllus\nviolaceus there are two little glandular tubercles, one on the right and one on the left of the buccal orifice, and situated at a nearly equal distance from the superior extremity of the ventral sinus and the dorsal nucleus or nerve-ganglion.\nThe branchial sac of the Botryllid\u00e6 is very similar to that of the Clavellinid\u00e6. The branchial spiracles, or intervascular spaces, are variable in number, and the crest or fold corresponding to the anterior border of the branchial sinus has no membranous languet ; but in Diazona, Synoicum, and Polyclinum it bears a row of minute tentacular filaments. The branchial sac of Sigillina has 4 large, salient, transverse vessels on each side, united by 15 or 16 smaller longitudinal vessels ; and in Aplidium there are 10 to 12 transverse branchial vessels. Polyclinum has 14 transverse branchial vessels anastomosing with 15 to 18 finer longitudinal vessels. In Amaroucium there are 10 to 12 rows of stigmata, and in Polyclinum 13 rows. Didemnum and Leptoclinum have 5 rows. In Botrylloides the respiratory sac presents 10 vertical rows of spiracles, parcelled into threes by vertical folds. There are 9 of these chink-like openings on each lateral rank, and at each of their four angles is a little tubercle. In Botryllus the respiratory sac lies almost horizontally, and has on each side 9 transverse rows of stigmata, grouped into threes by the longitudinal folds. The angles of the branchial net-work are marked with papillae in Bistoma and Diazona.\nInstead of papillae on the spaces between the branchial meshes, Leptoclinum Listen has a thin ledge between each row of spiracles ; and in front there are three tapering moveable prominences, one connected with each ledge, either stretched forward horizontally into the cavity, or bent downwards with a spiral curve. These laminae, observes Mr. Lister, seemed to suspend a generally invisible vertical membrane, and to assist in giving the food its direction towards the stomach ; for it moved horizontally along the sides of the cavity, as in Perophora, and when it reached the front, took a spiral motion downwards. When the branchial sac of the Leptoclinum contracted forcibly to reject what had been stopped by the tentacles, or found unfit for food, the oral orifice, instead of projecting, was then drawn down below the level of the external test, and depressed it, the cilia being also closely stretched across the openings of the spiracles. When the cilia were thus stopped in their action, they were seen to be very numerous, and being in close contiguity one with another, the neighbours by their sides, and the opposites by their ends, appeared almost as a continuous membrane.\nThe superior abdomen of the Polyclina contains the digestive apparatus, and the postabdomen the organs of generation and the heart. The intestines of the Botryllid\u00e6 are always subject to one or more foldings, and their several portions are frequently distinguished by different tints of colour.","page":1219},{"file":"p1220.txt","language":"en","ocr_en":"1220\nTUNICATA.\nThe superior abdomen in Amaroucium is short and rounded, and slightly separated from the thorax. The oesophagus is very short ; the stomach in A. proliferum is marked externally with a series of vertical folds, the edges of which, seen under the microscope, are furnished with secretory follicles. In A. argus, the exterior of the stomach is coated with a tessellated series of irregularly hexagonal, gland-like, bodies, having the appearance of a number of minute honeycomb compartments, around each of which are radiating lamellae or folds. In Sidnyum the stomach is also surrounded with glands ; and in this genus the intestine is spirally folded. In Diazona the stomach is striated externally; its inner surface is provided with numerous salient folioles ; and the pyloric entrance is guarded with an annular fold or valvule. The intestine in its first part is simply membranous, but afterwards it is furnished with irregularly disposed glands, which have the form of caecal tubes. The stomach of SigUlina bears some slight ridges on its inner surface, the strongest of which correspond to external furrows. In Aplidium the stomach is somewhat oblong and truncate, and is divided by deep plications into three longitudinal cavities, or rather into five, the lateral ones being subdivided. The intestine is bent sometimes forward and sometimes backward ; in the latter case it passes upward obliquely on the right side of the stomach ; the rectum is sometimes spirally arranged, and sometimes straight. In Polyclinum also the intestine is spirally folded, obliquely traversing the left side towards the anal orifice. In A. proliferum and A. argus the rectum ascends to the middle of the cloaca. The post-abdomen is elongated, narrow, and tapering, divided from the digestive cavity by a marked constriction. The ovary occupies nearly the whole length of this cavity (fig. 782. p), and is partially surrounded by the glandular mass of the testicle, from which latter an undulatory vas deferens runs upwards to end in the cloaca near the termination of the rectum. The ova are whitish, yellow, or brown, and on escaping from the ovary appear to pass to the cloaca by the vacant space between the intestines and the interior of the mantle. The heart is a tubular vesicle, bent on itself, and situated at the inferior apex of the ovary.\nIn the Didemnians the digestive, generative, and circulatory organs are grouped together in the pedunculated abdomen, and offer nothing remarkable. The ovary is situated by the side of the intestine, and protrudes downwards only when full of eggs, which in this case have, when fully developed, a large size, compared with that of the animals. The mantle of the Didemnum, as in many other Botryllidce, is frequently produced in the abdominal region into stolon-like processes, which traverse the common test. These swell at their extremities into reproductive buds, from whence arise new animals. Of these proliferous tubes we shall have to speak hereafter.\nThe stomach of Botrylloides rotifer a (fig. 783.) is pyriform and divided into seven or eight lobes by furrows that pass horizontally from the cardiac to the pyloric extremity. The intestine is sigmoid, and is divisible into three portions ; the first part is smooth and transparent, the second is surrounded with a granular tissue, and the third is membranous like the first. A glandular mass, apparently the hepatic organ, is situated at the commencement of the third portion of the intestine, and gives rise to many minute excretory ducts that soon unite into a single trunk, which appears to empty itself into the intestine near the pylorus. Below this organ and more behind, is another glandular mass, which apparently belongs to the generative organs, and gives origin to a little duct passing upwards to the cloaca. The heart is situated laterally, reposing on the cardiac side of the stomach. In B. rubrum the ovary is double, one part being situated on either side of the thoracic chamber. The testicle is seldom very distinct in the Didem-nina and Botryllina, but has been occasionally observed.\nThe nerve-ganglion between the two orifices, or rather on the dorsal side of the buccal orifice, is generally more or less distinct in the Botryllidce.\nThe circulation of the Botryllidce does not materially differ from that of the other Asci-dians, and has the same peculiar periodical change in the direction of the blood-currents. In the Polyclinina the heart is placed quite at the inferior extremity of the post-abdomen. It is invested with a thin, transparent pericardium, and has the form of a large contractile tube, bent on itself, and tapering at the extremities. In the Didemnina the heart is shorter, and instead of being situated beneath the ovary, it is lodged with that organ, by the side of the intestinal loop, this condition approaching that existing in the Clavellinidce. Lastly, in the Botryllina, it ascends still higher, being seated near the stomach, nearly at the base of the branchial sac. Milne-Edwards, to whom we are indebted for the preceding facts, remarks that these different positions of the heart always coincide with analogous changes in the position of the ovarium. It is also the same, says he, in the simple Asci-dians ; and Cuvier was, without sufficient reasons, led to consider that the heart followed in its position that of the mouth.\nIf, says M. Edwards, we separate from the common test of any of the Polyclinian species a lively individual, and place it under the microscope with a little sea-water, the movements of the heart may be easily studied. The heart\u2019s contractions succeed each other somewhat regularly, but they are not brisk and extending at once through the organ, as in the generality of animals. The contraction commences at one of its extremities, and the narrowing of the tube is propagated in an undulatory manner towards the opposite extremity, in a manner somewhat similar to the peristaltic movements of the intestines in the higher animals. For some time the contrac-","page":1220},{"file":"p1221.txt","language":"en","ocr_en":"1221\nTUNICATA.\ntions follow each other somewhat rapidly, and have all the same direction ; but suddenly they are arrested, and then recommence in a contrary direction. The blood thus sent sometimes from behind forwards, and sometimes vice versa, ascends towards the thorax ; but does not appear to be conducted thither by vessels. It is poured out between the inner tunic of the abdomen and the viscera lodged in that cavity ; and here it forms currents, which vary in their position according as the movements of the animal, or any other mechanical causes, oppose their passage. In general, however, the chief portion of the blood ascends by the dorsal or the ventral surface of the abdomen ; and after having bathed the surface of the viscera, it gains the base of the branchial sac. When the heart\u2019s contraction is from behind forward, the ascending current passes along the anterior side of the abdomen, and the blood enters a large vertical canal, on the front of the respiratory cavity, termed by Milne-Edwards the great thoracic or ventral sinus. This median sinus gives rise on each side to a series of large transverse vessels, which intercommunicate by means of a number of minute vertical vessels, and which, after having formed a kind of vascular network, spread over the walls of the branchial cavity, and terminate in another vertical canal parallel to the ventral sinus, but situated on the opposite side of the thorax. A portion of the blood arrives at the same time in this dorsal sinus without having traversed the branchial net-work, by means of a vessel that arises from the superior extremity of the great ventral sinus and surrounds the base ot the branchial orifice. Lastly the blood spreads out between the viscera and the internal tunic of the body, descends along the dorsal side of the abdomen, and again reaches the heart. If the circulation were constant in the above direction, it would somewhat resemble that of the other Acephalans. The heart might then be compared to an aortic ventricle, the thoracic sinus to a great branchial artery, and the dorsal sinus to a branchial vein. But owing to the contrary directions of the blood-currents, from the periodically varying impulses of the heart, the vessels that fulfil at one time the functions of veins, at another become arteries, and vice versa.\nThis peculiar extra-vascular circulation, so well described by Milne-Edwards, is also very distinctly seen in the Clavellince. The learned professor especially notices C. nana as highly illustrative of this phenomenon, the interabdominal space being in this case very large, and the currents of the nutritive fluid, with its suspended spherical globules, being easily discernible through the transparent integuments.\nMr. Bowerbank has favoured me with an account of some observations made by him on the circulation in the common tegumentary mass of Botryllus. Under the microscope, the more transparent portion of the test exhibited a reticulated arrangement of sanguiferous channels or vessels ; perhaps the true\n\u201c marginal vessels \u201d of Savigny ; each mesh, formed by the anastomosing currents, being occupied by one of the star-like \u201c systems \u201d of animals. No communication could be traced between the circulation and that of the animals themselves ; the former appearing to be analogous to the peculiar stem-circulation of the polypifera, to which also the circulation of the nutrient fluid in the budless stems of Perophora, noticed by Mr. Lister, vide supra, has reference.\nEmbryogenesis of the Botryllid\u00e6.\u25a0\u2014Tn the development of the ova of the compound Asci-dians, there are certain striking differences from the conditions that take place during the embryo-genesis of the Ascidiad\u00e6. These, however, are chiefly confined to the composition of the egg, the formation of the Blastoderm, the mode of growth of the caudal appendage, the organs of vision, and the anterior appendages. From the elaborate observations of this family, given by Professor Milne-Edwards in his Paper before referred to*, it appears that the ova of several species of the Polyclinina are, whilst still enclosed in the ovary, and before that their development is much advanced, of an ellipsoid form, and are composed of a very thin external membrane, a subgelatinous whitish and granular inner mass, and a minute central vesicle filled with a watery fluid. The internal vesicle is the vesicle of Purkinje, or the proligerous vesicle ; the granular substance surrounding the vesicle is the imperfect vitellus, the vitelline membrane being the external envelope.\nWhilst these ova are still enclosed in the upper part of the post-abdomen, they grow rapidly and become spherical. But the most remarkable change that takes place consists in the colour of the vitellus, which is at first a pale, and afterwards a deep yellow. The vesicle of Purkinje is still visible at the commencement of this period of the development, but it soon disappears, and there then appears on the surface of the vitellus a nebul\u00f6se spot of pale yellow, which appears to be the blastoderm or proligerous layer destined to become the embryo of the young Ascidian.\nThe ova arrive in the cloaca, and sometimes are even lodged in the lateral portions of the thoracic chamber, without having undergone any other appreciable modification. M. Milne-Edwards considers it probable that the fecundation of the ova takes place in the interior of this cavity. They are here brought into contact with the spermatozoa, and very shortly after having arrived here, they exhibit evidences of active internal changes.\nThe granules composing the vitelline mass become grouped into clusters, forming themselves, as it were, into balls, and giving the surface an embossed or mulberry-like aspect. At the same time there is formed between the yolk and the external membrane of the ovum, a gelatinous, transparent, and nearly colourless layer, which apparently becomes the external tunic or test of the young animal.\n* Observations sur les Ascidies compos\u00e9es.\n4 i 3","page":1221},{"file":"p1222.txt","language":"en","ocr_en":"1222\nTUNICATA.\nWhen the ova, lodged in the marsupial pouch or cloaca, have arrived at a rather more advanced period of their development, the vi-tellus loses the mulberry appearance it had but lately put on, and, if compressed between two slips of glass, it is seen to be wholly composed of minute globules or granules of different sizes. The ovum is soon a little flattened, and the yolk appears to be concentrated\nFig.\ntowards the middle, forming an ovoid mass of a deep yellow colour, surrounded by a somewhat large border of a clearer tint. This marginal portion of the yolk is condensed in its turn, and although at first sight appearing to constitute a sort of ring, becomes a long tapering prolongation, which encircles the central part of the yolk, adhering by its base, and having its pointed extremity free (fig. 784. a).\n784.\nThe Development of the Larva of Amaroucium proliferum. (After Milne-Edwards.')\nA. An ovum the incubation of which is far advanced, magnified about 30 times. The tail, (ft') is becoming distinct from the trunk (ft) ; and two lobules begin to appear on the anterior extremity of the latter (ft'').\nb.\tAn ovum arrived at the full term of incubation, magnified about 30 times, a, the tegumentary portion ; ft', caudal portion ; ft\", ft'\", anterior appendages.\nc.\tLarval ascidia lately born, magnified about 25 times, a, tegumentary portion; ft, sac enclosing the yolk and forming the proper tunic of the body of the larva ; ft\", processes terminating in suckers, and serving to fix the animal ; a, tail formed by a prolongation of the integuments, and enclosing a tubular appendage of the vitelline sac.\nD. The same larva, observed some hours after having fixed itself, magnified about 20 times. 6\", traces of the anterior processes ; ft', vitelline prolongation of tail nearly absorbed, and the central sac, enclosing vi-tellus, is spherically contracted.\ne. The same larva about 20 hours after fixing, magnified about 25 times. The caudal elongation of the internal tunic (containing the vitelline matter) has entirely disappeared, and this tunic (ft) has taken the form of an ovoid sac, slightly contracted in the middle ; a pale yellow circle (d) at the anterior extremity surrounds a spot that will become the mouth, and posteriorly another, clear, spot (c) appears, in which the heart will be developed.\nF.\tThe same larva seen at the end of the second day of its sedentary state, magnified about 25 times, ft, tunic proper ; c, pericardium spot ; e, branchial sac, beginning to be developed ; f, thoracic sinus ; g, cloaca ; /, stomach ; m, intestine, full of f\u00e6cal matter ; a, vestige of tail, of which a part only is figured. The external orifices are not yet formed. The development of this individual was much more rapid than usually is the case.\nG.\tAnother individual, about 8 days old, magnified. Animal completely reversed in the interior of the tegumentary envelope ; d, oral orifice ; i, anal orifice ; l, stomach ; m, intestine ; o, heart.\nH.\tIndividual about 20 days old, magnified (lying with its anterior extremity to the right), a, tegumentary envelope ; m, f\u00e6cal matter in the intestine.\nIn the course of incubation, the ovum increases in size, becoming flatter and more oval. The vitelline mass becomes more compact, and its surface denser; and the latter seems to be organised into a membrane, distinct from the yolk beneath. The two portions of the ovum, before described, become more and more separate; that which occupies the centre of the ovum becomes ovoid, and knotty at one of its extremities ; near the other extremity, which is continuous with the marginal portion, are seen one or two blackish minute points. This ring-like portion is now seen to be a caudal prolongation, too short completely to encircle the central part, from\nwhich also it is distinctly divided a little in front. Lastly, the whitish substance surrounding the vitellus, and constituting the tegumentary mass, increases considerably in thickness.\nWhen the ova more nearly approach maturity, the tail-part of the vitellus is shortened, and its central part, or body of the embryo, is more and more condensed. Its anterior extremity becomes lobulated and encircled with a series of five cylindrical processes, which have a divergent arrangement, and advance towards the border of the egg. Three of these appendages terminate in a kind of button, and the intervening two are tapering anteriorly.","page":1222},{"file":"p1223.txt","language":"en","ocr_en":"TUNICATA.\t1223\nAt each side of the base of the group of tentacles, a little prominent lobular process is present. Lastly, the side of the body, opposite to that on which the tail is placed, becomes somewhat strongly embossed near its posterior extremity, and towards the space where the above-mentioned black points occur {fig. 784. b).\nThe ovum ready for exclusion differs apparently little from the foregoing state. The two anterior styliform appendages have almost entirely disappeared, and the three obtuse processes are further developed. The trunk is contracted towards its anterior extremity, and the yolk-mass still further condensed at the centre of the ovum.\nThe external membrane of the ovum becomes excessively thin, and then breaks and allows the embryo to escape. Generally this exclusion takes place in the interior of the cloaca, but sometimes not until the ova have passed out by the anal orifice. However that may be, the young animal, free from its envelopes, soon extends its tail, and swims in the ambient fluid by the aid of its undulatory movements. In its general form the young Ascidian resembles somewhat that of a newly born tadpole {fig. 784. c) ; but it still more resembles a Cercaria. The trunk or body of the larval Poly-clinuvi is oval and rather depressed. The whitish tissue of the future integument occupies all the surface, and is considerably developed at the margins ; its substance is granular and apparently subgelatinous ; its consistence is greatest at the surface; and it does not appear to possess a membranous investment. Towards the centre of the trunk is a large elliptical membranous sac, the internal tunic of Milne-Edwards ; this is filled with the yellow substance of the vitellus, and is continuous anteriorly with the three tubes dilated at the end, and terminating at the anterior wall of the egg in a sort of sucker. By means of gentle graduated pressure, some of the yolk may be easily made to pass from the principal sac into these appendages, and vice versa ; the little capsule, also, terminating each of these appendages can be made to protrude externally by the same means. At the base of these three processes the vestiges of the others formerly occupying the intervening spaces may be observed. The yellow substance contained in the internal tunic appears to be separated into two portions; the one is clear, and situated near the wall of this sac, and the other, denser and of a deeper tint, occupies the centre. Posteriorly a little marginal space, clearer than the neighbouring parts, is also visible, and on one of the sides the above-mentioned minute black spots are visible. The tail is very large, and, like the trunk, is composed of two distinct parts ; the one superficial, colourless, diaphanous, gelatinous, and much resembling the albumen of the eggs of frogs ; the other, central and yellow. This latter part is continuous anteriorly with the central sac of the trunk, and is also composed of a membranous tunic, enclosing a yellow granular and semi-fluid substance. It sometimes appeared to have a\ncentral canal. The larvae, after swimming about with an active wriggling motion for a few hours, attach themselves to the surface of a solid body, and, if disturbed from their position, swim about as before until they meet with a similar situation. Their activity having ceased, they become permanently fixed, and are then about the size of the head of a very small pin. They appear to affix themselves to their resting place by means of one of the little suckers with which their anterior extremity is furnished.\nThe larva has now lost all power of locomotion, and quickly undergoes further changes of form. The anterior extremity of the trunk is widened, and the prolongations of the internal tunic quickly disappear. The central portion of the tail becomes at the same time empty, its contents being returned to the central yolk-mass of the body. The sac or internal tunic enclosing the yolk becomes much contracted and spherical ; lastly, the yellow matter, which was unequally divided, seems again to be rearranged. The tail, which during the early period of the existence of the larva performed so important a part, being the only instrument of locomotion, is now reduced to its gelatinous or tegumentary portion ; and this, after becoming more and more transparent, withers, and finally is detached, or falls away in shreds at a more advanced period of the growth of the animal. The trunk, on the other hand, is the seat of important and active changes. The tegumentary portion of the body is much widened, taking an oval outline, and is visibly augmented in bulk. The interior tunic continues at first to lessen, and becomes quite spherical, and many large patches of a lighter yellow than the rest are apparent, one of which occupies the anterior, and two others the posterior portions of the tunic {fig. 784. \u00bb).\nM. Milne-Edwards further remarks, that the modifications already noticed ordinarily occupy the space of from ten to twelve hours ; and if the larv\u00e6 are again examined towards the end of the first day of their sedentary existence, further changes in the interior tunic may be observed. In a specimen carefully watched by him, the following changes were noted. Instead of being spherical, the large yellow sac became oval, and its anterior part much thinned. It soon afterwards again became elongated, and a circular contraction divided it into two portions {fig. 784. e). The anterior portion, smaller and lighter coloured than the posterior, was rounded in front, and presented at that part a large annular patch of a deep yellow, vaguely circumscribing a central paler portion. The posterior part was swollen and of a deeper yellow than the anterior, and quite behind there was observable a minute patch of a very clear yellow. This latter spot subsequently became the heart, and the annular spot on the other extremity of the body was developed into the thorax of the animal. The following day all these parts grew still more distinct. The anterior portion of the inter-\n4 i 4","page":1223},{"file":"p1224.txt","language":"en","ocr_en":"1224\tTUNICATA.\nnal tunic or the thorax, which had been smaller than the abdominal or posterior portion, was much increased, and far more diaphanous, and the part occupied by the whitish anterior spot was somewhat elevated in the form of a nipple, marking the future position of the mouth. The obscure circle that surrounded the base of the buccal region was now replaced by a very narrow yellow band ; and on the inferior part of this thoracic portion of the body there were observed two yellow lines, vertically dividing it into three nearly equal lobes. The abdominal portion of the internal tunic was, on the contrary, much straitened ; the pericardial spot was more distinct; and another less distinctly limited spot, situated more in front, presented apparently the first indication of the stomach. Towards the middle of the second day, the middle lobe of the thorax was much enlarged, and in certain positions of the animal appeared to be formed by a new interior cylindrical sac, which in front united with the anterior wall of the thorax at the point occupied by the yellow ring before described, whilst laterally it was separated from the internal tunic by the spaces corresponding to the lateral lobes already mentioned. One of these lobes became very much narrowed, and seemed destined to form the great vascular sinus : subsequently, traversing the anterior surface of the thorax, the other lateral lobe appeared to correspond to the future cloaca ; and the middle lobe was evidently the branchial sac, from the base of which arises the digestive tube.\nA few hours after, the anterior nipple-like prominence was more salient, and seemed to be contractile. The situation of the stomach and the course of intestine were also distinguishable in the abdomen (fig. 784. f). The yellow substance had now in a great degree disappeared, but it was still present in a pretty considerable quantity in the alimentary tube, and appeared to pervade all the interior parts of the young animal.\nTowards the end of the second day, the branchial orifice was easily distinguished at the summit of the thorax, and its margin began to be somewhat crenulated. This orifice, however, was present only in the internal tunic, the tegumentary substance being continued over it without interruption. The nerve-ganglion appeared in the form of a minute tubercle. The yellow line encircling the summit of the thorax appeared as the superior margin of the branchial sac. All the thoracic portion of the body contracted itself from time to time. Lastly, the anal orifice began to be visible.\nOn the third day, the heart was seen to pulsate, and pellets of faecal matter were visible in the intestine. The following day, the mouth opened externally, and the water passed through it to the branchial cavity. About the same time, the integument was perforated also by the anal orifice, from which faecal matter was discharged, provided without doubt by the digestion of nutritive matter furnished by the vitelline mass (fig. 784. g).\nOn the following days, the growth of the\nyoung animal was more rapid, its organs became more distinct, and soon afterwards the spiracles of the branchial sac, disposed in transverse rows, were visible, as well as the vibratile movements of the cilia, with which the stigmata are fringed. The number of these rows, however, was but four, the adult animal having ten.\nThe young Amaroucium was now provided with all its necessary organs except those of generation, of which no trace was yet visible, and the future situation of which was occupied by other organs, the heart being close up to the intestinal tube. The general form of the body resembled more that of aDidemnian than of a Polyclinian, for it had as yet no postabdomen, and the loop of the intestine was folded up against the inferior extremity of the thorax. Lastly, during the succeeding days, the abdomen very much lengthened itself (fig. 784. h), and at the end of the second week there was present, between the heart and the intestine, a granular mass, which by its appearance and position could readily be recognised as the generative organs.\nWith regard to the development of the integuvient of this, at first solitary, but subsequently compound, Ascidian, and which is evidently the analogue of the polypary of the Polypifera, we have mentioned that at first it is a gelatinous layer, surrounding the yolk. An inner membrane, immediately investing the yolk, and regarded as the blastoderm, becomes the internal tunic of the animal. Whilst the larva goes through its early changes, there appears no connection at all between the inner tunic and the integument. Indeed, says M. Milne-Edwards, the larva may be seen sometimes to be entirely turned round in the cavity of the tegumentary envelope ; and sometimes, when it abandons its original position, it forms a kind of hernia on the exterior of this envelope, by distending it at a weak spot (fig. 784. g). The learned professor does not, however, regard this envelope as being either a deposit produced by secretion, or as an organised body that had ceased to live since it had ceased to be attached to the interior parts of the animal ; because, as he observes, it continues to grow and gives unmistakable signs of vitality. Thus, not only does its bulk rapidly increase, but it frequently gives rise, as in Amaroucium Nordmanni, to lobe-like expansions, frequently changing their form, contracting and dilating very gently, and appearing to have some analogy to the proteiform expansions of the Amcebce and other inferior animals. Of these changes Professor Milne-Edwards has given an interesting series of figures.\nIt is only when the mouth and the anus open externally, that an attachment is established between the integument and the internal tunic of the animal ; and then, as throughout its future existence, it is around the two orifices only that organic continuity exists between the two parts, one only of which is in direct relation with the organs of animal life. It is consequently probable that the nutrition","page":1224},{"file":"p1225.txt","language":"en","ocr_en":"1225\nTUNICATA\nof the test is carried on by imbibition only ; and M. Milne-Edwards points out the fact of the independence of these two portions of the body of these Ascidians during the early periods of their life, as worthy the consideration of physiologists ; and he adds, that probably this kind of vitality of the integument of the larval Ascidians has some analogy with what obtains in Sponges, and may, perhaps, throw some light on the peculiar existence of the basilar portion of the Sertularice and other Polyps, that continue to live for some time after the loss of the soft parts that are generally, but wrongly, regarded as constituting the entire animal.\nFrom observations made by the same naturalist on the development of the ova and larvae of other species of the Polyclinina, and of the Didemnina and Clavellin\u0153, it appears that very similar modifications take place ; the time occupied in the development being of course variable according to specific and external conditions. The larvae of Clavellina have the internal tunic strongly lobed in front, very tumid behind, and destitute of the peculiar appendages observed in the Polyclinina. These appendages exist in the Didemnina, but are very short ; and at their base are seen a row of pyriform lobules, which might easily be taken for the germs of young individuals, but all of which really belong to one individual.\nThe observations made by MM. L\u00f6wig and K\u00f6lliker on the embryogeny of some of these animals are generally in accordance with those of M. Milne-Edwards, but on some points, and especially with regard to the development of the Botrylli, there exists considerable discordance of opinion. The points involved being not only of interest, but of no slight importance, it is necessary to give in detail some of the most important observations recorded by the above-named naturalists.\nIn Botryllus violaceus, B. aureus, Apli-dium gibbulosum, and Amaroucium Nordmanni, MM. L\u00f6wig and K\u00f6lliker observed, in the first stages of development, a division of the yolk similar to that taking place in the eggs of frogs, and described also by M. Milne-Edwards, and established also in the case of the simple Ascidians by Van Beneden. This division takes place as in the intestinal worms ; that is to say, the simple nuclei, contained in the globules, which, as everywhere, are only aggregations of granules, always become double before the globules are divided in two. As soon as the division has arrived at a certain degree, the spherical form of the mass of globules becomes elongated, and takes more and more the form of an embryo, its tail making a semicircle about its body. The tail is distinct before any other part, and this, according to these observers, is evidently formed, not by an elongation of the embryo, but by the separation of a portion of the globules from the surface. In Amaroucium and Aplidium, at the same time as the exterior form of the embryo, and at a very early period, the two ocular points, remarked by Milne-Edwards, make their appearance; presenting as yet no trace of an\nenvelope or of anterior processes. At a later period only is there formed around the embryo a transparent, colourless border, which, in Amaroucium and Aplidium, increasing more and more, especially at the thick end of the body, appears as a very strong lamina, but remains without structure all the time the embryos are contained in the membranes of the egg. Cotemporaneously with the formation of the envelopes, the embryos themselves commence also to undergo a series of changes. Firstly, towards the anterior extremity, there appear the three appendages of peculiar form ; secondly, the yellowish substance in the interior of the body separates into two laminae ; the one, external, remains diaphanous ; the other, internal, becomes opaque, and divides, in the Botrylli, into eight conical corpuscles, which surround a somewhat large, round, perforated nipple ; lastly, a great number of structural modifications take place. The mature embryos of B. aureus are formed of a spherical body, 0*28/// broad and (b\u00f6S'\" long, possessing an orifice surrounded anteriorly with three lobules, and posteriorly bearing a thin, tapering tail, 0'7&\" long. These embryos present exteriorly the thin, transparent, structureless layer (tegumentary layer) before referred to, from which almost solely the lobes, or lanceolate appendages of the head, are formed, and which terminate at the opposite extremity in a prolongation exceeding in length those parts of the tail enclosed within it. Interior to this, in the anterior part of the bod}', is a second delicate envelope, formed of cells either round or changed into fibres, which does not enter into the composition of the lobes of the head, but encases the mammil-lated prominence before described, and also the eight spherical bodies surrounding it, and is attached at one end to the edge of the nipple, and at the other to the interior part of the tail.\nThe internal substance, constituting the chief mass of the embryos, is, according to MM. L\u00f6wig and K\u00f6lliker, evidently a group of individuals, as M. Sars, who discovered those curious embryos of the Botrylli, has already shown. The eight spherical corpuscles, united at their bases, and provided with a kind of common stem, are so many individuals, and the prominent nipple situated in their centre represents the common excretory tube. This salient tube at its extremity has three lobules, which project into the base of the lobes of the exterior envelope : from its base three filaments (nerves ?) arise, which passing upwards bifurcate each into two, one of which terminates at the orifice of the tube ; the second reaches the summits of the lobules, and, passing beyond them, spread into five or six branches, extending almost to the edge of the lobes of the exterior envelope. In the eight embryos no orifice is perceptible, nor any other organs, except some canals (intestine) indistinctly rolled up. Their microscopic elements, however, are very distinct ; namely, various-sized nucleated cells, filled with pale red granules and fibres in","page":1225},{"file":"p1226.txt","language":"en","ocr_en":"1226\tTUNICATA.\nprocess of formation ; the former constitutes the principal mass of the excretory tube. The internal part of the tail, which is apparently a direct continuation of the substance of the embryo, possesses an interior cavity, and its walls are composed of two layers of cells. The internal layer is formed of cells of 0*012/// diameter, rectangular, with the angles slightly rounded, distinctly nucleated, and containing fine yellowish granules. They are very regularly arranged side by side in transverse series, so that the cavity of the tail is always surrounded by 10\u201412 cells. The external layer is composed of a continuous, simple layer, formed of minute cells, measuring O-OOS'\"\u2014O\u2019OO-P\", without any distinct arrangement. It is to be observed that this tail, formed simply of cells and a homogeneous envelope, exhibits very active movements, affording a new proof of the contractility of parts composed merely of simple cells.\nThe body of the embryos of Aplidium and Amaroucium is formed (at an early stage) of a thick, homogeneous, external layer, and a yellowish mass enclosed within it. In the spherical portion of the body, this mass is apparently wholly composed of round cells, of different sizes, and containing nuclei, and, towards the interior, probably unaltered globules produced by the division of the vitellus. These two elements do not compose any distinct organ ; but only form two layers, one internal and opaque, and the other external and diaphanous. In Amaroucium Nordmanni there is no canal within the tail, but its centre is occupied by a simple series of large rectangular nucleated cells, producing a transversely radiated appearance, visible even when moderately magnified ; the tail has also an external simple layer of minute cells, as in Botryllus.\nSavigny, also, was led by his researches to regard both the ovum of Botryllus and that of Pyrosoma as giving birth to several individuals having already a certain order of arrangement. This view, in the case of the Botryllus, is, as we have seen, supported by L\u00f6wig, K\u00f6lliker, and Sars, and is considered by Van Beneden as founded on fact and supported by analogy. Milne-Edwards, however, is not disposed to admit this conclusion ; for, in his opinion, the existence of the four embryos united in a circle in the Pyrosoma, and the development of a single star of germs in the larval Botryllus, do not sufficiently account for the association of many such groups in the adult age; there being, for instance, in the adult Pyrosoma, many hundred individuals of different degrees of development. Van Beneden thinks it probable that the presumed aggregate larvae produce colonies similar to themselves by fis-siparous reproduction; but Milne-Edwards gives it as his confirmed opinion that, from the single product of the ovum, the other associated individuals arise by gemmiparous reproduction only. Of this mode of generation in the Botryllidce we will now proceed to give a slight sketch, again acknowledging the labours of the learned Professor of the Garden of Plants as the chief source of our information.\nIn Diazona, Didemnum, Botryllus, and Bo-trylloides, the common test is traversed by numerous ramifying prolongations of the inner tunic of the individual animals, terminating either simply in culs-de-sac, or swelling out into germs (fig. 785.). Savigny figured these\nPig. 785.\nVertical Section halfway through a Mass of Botryllus, magnified about 6 diameters. (Original), a, animals on one, of the exterior surfaces of the mass ; b, proliferous stolons, traversing the mass, and hearing reproductive germs.\ntubular bodies, and vaguely described them under the name of \u201c marginal tubes \u201d and \u201c vascular branches.\u201d And Delle Chiaje*, in treating of Polyclinium, figures and describes \u201c vessels \u201d which are probably these ramifying canals. These membranous tubes, with their terminal vesicular enlargements, are readily seen during life in those species that possess a semitransparent test. Milne-Edwards observes that in Botryllus and Botrylloides, (figs. 785 and 783, t, t'), each of these interior appendages appears at first as a little tubercle on the surface of the abdominal portion of the inner tunic of the adult animal. The tubercle then becomes elongated, forming a tube, the free extremity of which is closed, its cavity communicating with the abdominal cavity of the animal from which it springs. The blood from the abdominal cavity circulates throughout this caecal tube, with a very active double current. As the tubes lengthen, they generally become ramified, and soon present swollen or claviform extremities. The circulation continues active, and before long there is visible towards the summit of each terminal swelling a minute granular mass, the colour of which approaches that of the thorax of the adult animals situated close by. A little later this organised mass begins to present the form of a little Ascidian, and soon afterwards becomes a young animal, similar to those already occu-\n* Memoirs, second edition, tom. i. p. 34. tabl. 83. figs. 13. and 15.","page":1226},{"file":"p1227.txt","language":"en","ocr_en":"TUNICATA.\t1227\npying the common mass, of which it becomes a new inhabitant. The communication between the mother and the young animal becomes obliterated ; but for some time yet, all the young individuals growing from the same branch remain united by their pedicle, and it is this union, apparently, that determines their mode of grouping into \u201c systems.\u201d * In JOi-demnum gelatinosum, the buds growing on these proliferous stolons are very different in appearance from the ova expelled by the animals ; for not only did they differ in aspect and form, but their bulk is at first twenty or thirty times less than that of the vitelline mass of the ova. In the Amaroucium proliferum, Milne-Edwards has frequently found on the surface of a rounded mass, formed by a colony of these animals, many little filiform twigs, simple or branched, formed by a prolongation of the common tegumentary substance, and consisting of a tube closed at the end, and enclosing, in its interior, one or more embryos in different states of development. These young individuals terminated inferiorly by a peduncle, prolonged in form of a slender tube into the common mass, and springing apparently from the abdominal tunic of an adult individual. This mode of propagation by buds, which the compound Ascidians possess in common with the Polypifera, is, as we have above described, found in the Clavel-linid\u00e6 ; the only important difference being, that in the latter the tegumentary envelope of the young is not so largely developed as in the Botryllid\u00e6, and does not become fused with that of the adults; whence it results that the individuals springing from the same stem remain isolated, instead of being united into a common mass.\nAnatomy of Pyrosoma. \u2014 The common tegumentary mass of Pyrosoma is semitransparent, subcartilaginous, toughish, and somewhat extensile. The exterior of the hollow, conical, or cylindrical body, formed by the aggregation of the individual Pyrosomata, is covered with numerous elongated tubercles, of a rather firmer consistence than the rest of the mass. Each of these constitutes one extremity of an individual member of the living group. The opposite extremity opens into the cavity of the cylinder, and is not free, but, like the trunk of the individual\u2019s body, is closely connected by the common mass with the similar parts of other individuals lying above, below, and on\n* M. Savigny figures a nascent system, originated apparently by this grouping of the buds ; and Professor Van Beneden coincides with M. Milne-Edwards in the above view of the subject, but M. Steenstrup expresses his opinion that the mode in which the colonies and systems of the Botryllid\u00e6 are formed, is not sufficiently explained by this hypothesis; and, although (following Milne-Edwards) he considers M. Sars to have been misled in regarding the ova of the Botrylli as producing groups of animals, yet he is inclined to consider this grouping to be really a f\u0153tal condition, but occurring in some hitherto unnoticed \u201c aggregate \u201d form of animal, produced from the \u201c solitary \u201d larv\u00e6 described by Milne-Echvards,justasthe solitary Salp\u00e6 bring forth Salpa-chains.\neither side of it. In some species the animals are arranged much more regularly than in others, and appear to form piled-up rings or circles of individuals, more or less analogous to the otherwise disposed circular systems of some of the Botryllid\u00e6. In Pyrosoma atlan-ticum the tubercles are simply conical, and are perforated terminally. In P. elegans, also, the external orifice of the individual opens at the extremity of the tubercle, and through it the water contained in the great cylinder has been seen to escape freely in little jets, when the Pyrosome has been taken out of the sea. In P. giganteum the tubercles are of various sizes, some being short and indistinct, and others, on the contrary, very much developed. The largest are conico-cylindrical flat, and lanceolate at the extremity, with the minute branchial orifice on the inferior aspect. This lanceolate extremity is crenulated on its sharp edges, and presents on its inferior aspect, between its point and the aperture, a slightly prominent keel. The branchial orifice is sometimes surrounded by a slight, free, crenulated membrane.\nThe interior of the great cavity is generally smooth. Its walls are perforated by the numerous minute anal orifices of the component individuals ; and, at a slight depth, its surface is studded with a great number of yellowish, rose-coloured, or carmine spots, which are the hepatic and other visceral organs of the numerous animals. The terminal aperture of the large, conical, compound body of the Pyrosoma has, according to Le-sueur and Savigny, a membranous border, which can be sometimes drawn together so as to close the cavity ; and Mr. F. D. Bennett observed that, when first removed from the sea, the broader extremity of the cylinder presented a wide and circular orifice, forming nearly a continuous surface with the central tube ; but when the animal was kept in a vessel of sea-water, or much handled, this orifice was closed by the contraction of a smooth, dense membrane at its margin, and which either obliterated the aperture, or left but a minute central orifice; water at the same time being contained in the barrel or tube of the body.\nBesides the common envelope or test, each individual animal has an inner tunic or mantle. This is a very thin, delicate membrane, attached apparently at four points only, two of which are at the extremities; that is, at the branchial and anal orifices ; and the other two are at two rounded, compressed bodies, one on either side, just beyond the anterior margin of the branchiae, and regarded by Savigny as ovaries.\nThe branchi\u00e6 line the inner surface of this inner tunic. They are oval in form, and their dorsal borders meet each other, and are attached along the dorsal aspect of the mantle ; but they are separated, at their anterior and ventral borders, by a considerable space, which is partly occupied by the ventral sinus (fig. 786. i,i). The branchial tissue is traversed by numerous vessels anastomosing with each","page":1227},{"file":"p1228.txt","language":"en","ocr_en":"1228\tTUNICATA.\nother at right angles. The transverse vessels, varying from 18 to 25 in number, are the\nFig. 786.\nAnatomy of Pyrosoma giganteum, magnified.\nA. A portion of the common mass with animals imbedded in its substance. (After Savigny.) a, a, a, a, the liver ; b, b, b, ova in the posterior cavity ; c, ovum in the substance of the common test ; d, d, d, full-grown individuals ; e, e, e, undeveloped individuals.\nb. A single individual cut out of the common test, with a portion of the latter surrounding it, seen from below. (After Lesueur.) a, branchial or external orifice ; b, anal or internal orifice ; c, c, delicate fibres traversing the test ; d, stomach ; e, liver ; f, f, bran-chi\u00e6 ; g, oviduct (?) ; h, ovary; i, ventral sinus; j, nerve-ganglion.\nC. The viscera of an individual Pyrosome. (.After Lesueur.) d, e, g, h, i, j, as in fig. b ; k, ovum.\nlargest and most distinct, and are folded back on themselves at the free edges of the tissue. The longitudinal vessels are from 11 to 17 in number. \u201c Nothing is more curious,\u201d says Milne-Edwards*, \u201cthan the respiratory apparatus of these little animals, when the vi-bratile cilia, with which each of the branchial stigmata is furnished, are simultaneously effecting their vorticiform movements with rapidity and perfect harmony.\u201d\nThe cesophagus is curved, and is of a bright red colour. The stomach is subglo-bular, yellowish, and opaque. The intestine is short, and strongly bent on itself ; the anus is directed backwards towards the posterior\n* Annales des Sciences Naturelles, sec. ser. tom. xii. p. 375. 1835.\norifice. The liver is a globular body, which is but slightly developed in young individuals ; its postero-inferior portion is formed of several sections united by a centre, around which they converge, presenting the appearance of a flower with many petals, or a calyx with, most usually, 7, 8, or 10 divisions. The sections are not always equal. Their centre is occupied by a somewhat solid, granular substance, which they more or less perfectly enclose. Its colour is generally whitish, or of a light pink. It lies free in a cavity hollowed out of the test, and is attached by a membranous peduncle to the stomach, or rather to the intestinal loop (fig* 786. a, a, a, B and c e,e). These viscera are situated posteriorly to the branchial sac. By their disposition they leave a free passage to the water which traverses the branchial cavity. The nerve-ganglion is present at the anterior extremity of the dorsal border of the branchial sac. From it there proceed filiform branches towards the neck of the external tubercle and in other directions. The vessel or sinus that runs between the two free edges of the branchiae is of considerable length, and has a slight general curve. It is divided, as it were, into four, towards its largest and anterior portion, or rather seems to be composed of two contiguous vessels bent upon themselves. These diminish in calibre as they run backwards, and, passing into a delicate filiform vessel, are lost near the stomach.\nTwo arching vessels, one on either side, pass from near the nerve-ganglion to the compressed oval bodies on the anterior lateral points of the branchi\u00e6, and a similar pair of vessels unite these latter bodies with the extremity of the loop formed by the vessel that lies between the free ventral margins of the branchi\u00e6. These four arched vessels form therefore a circlet around the anterior extremity of the branchial sac {fig. 786. b, h).\nThe heart is placed at the posterior part of the body, at the side of, and below, the visceral mass. Its character is perfectly analogous to that of the heart of other Ascidians. It contracts with the usual peristaltic_ movement, and changes periodically the direction of this vermicular movement, the vessels alternately playing the part of artery and vein.\nWith regard to the generation of the Pyroso-midee, very little has yet been observed. Savigny describes as \u201coviduct\u201d and \u201csiphon-canal\u201d the vessels that occupy the usual position of the dorsal sinus, running along the dorsal or superior surface of the branchial sac (fig. 786. g, g). They have, however, no apparent connection either with the presumed oviferous bodies situated at the anterior points of the branchi\u00e6, or with the cavity posterior to the abdominal viscera occupied by the ova in Savigny\u2019s specimens (fig. 786. a, b). Lesueur discovered and described certain globular, transparent bodies in Pyrosoma, situated near the liver ( fig. 786. c, k), which he regarded as ova ; these were noticed also by Savigny. Each enclosed four minute Py-rosomes, symmetrically disposed, and readily","page":1228},{"file":"p1229.txt","language":"en","ocr_en":"TUNIC AT A.\t1229\nrecognised by the form and arrangement of their double branchiae.\nWhether the ova of Pyrosoma be always composed of four, or a greater or less number of young individuals, or whether the}' generally contain but a single one, it is still highly probable that gemmiparous reproduction obtains with these animals ; the fissi-parous mode, however, imagined by P\u00e9ron as possibly occurring in the adult Pyrosome, is totally unsupported by evidence. The several stages of development in which the individual animals are found to exist in the common mass of the test, as noticed by Savigny, point to this conclusion ; and possibly the delicate fdaments regarded as muscular fibres by Savigny, first pointed out by the acute observer of these creatures, Lesueur, as traversing the test in a line with the abdominal cavities of the adult animals (Jig. 786. B, c), may be the proliferous stolons as yet untraced throughout their course.\nPhosphorescence of Pyrosoma. \u2014 M. P\u00e9ron, who first discovered and established the genus, has given a lively description of the circumstances under which the P. atlanticum were first met with by him, in his M\u00e9moire sur le Pyrosome. * \u201c We had,\u201d says he, \u201c for a long time been detained by calms in the equatorial regions, between 19\u00b0 and 20\u00b0 long, west of Paris, and 3\u00b0 and 4\u00b0 north lat., the temperature of the sea being at the surface 22\u00b0 Reaumur ; and we could make no progress except by the aid of the short-lived storms peculiar to these climates. In the evening of the 13th Frimaire we experienced one of the strongest of these squalls ; the sky was on all sides loaded with heavy clouds ; all around the obscurity was profound ; the wind blew violently; and the ship cut her way with rapidity. Suddenly we discovered, at some distance, a great phosphorescent band stretched across the waves, and occupying an immense tract in advance of the ship. Heightened by the surrounding circumstances, the effect of this spectacle was romantic, imposing, sublime, rivetting the attention of all on board. Soon we reached the illuminated tract, and perceived that the prodigious brightness was certainly and only attributable to the presence of an innumerable multitude of largish animals floating with the waves. From their swimming at different depths they took apparently different forms ; those at the greatest depth were very indefinite, presenting much the appearance of great masses of fire, or rather of enormous red-hot cannon-balls ; whilst those more distinctly seen near the surface perfectly resembled incandescent cylinders of iron.\n\u201c Taken from the water, these animals perfectly resembled each other in form, colour, substance, and the property of phosphorescence, differing only in their sizes, which varied from 3 to 7 inches. The large, longish tubercles with which the exterior of the Pyro-somes was bristled were of a firmer substance and more transparent than the rest of the\n* Annales du Museum d\u2019Hist. Nat. tome iv. 1804.\nbody, and were brilliant and polished like diamonds. These were the principal seat of phosphorescence. Between these large tubercles, smaller ones, shorter and more obtuse, could be distinguished ; these also were phosphorescent. Lastly, in the interior of the substance of the animal, could be seen, by the aid of the transparency, a number of little, elongated, narrow bodies (viscera), about a millim\u00e8tre in length, which also participated in a high degree in the possession of the phosphoric light.\n\u201c The colour of the animals, when at rest or when moribund, was observed to be of an opaline yellow, mingled with a disagreeable green; but during the spontaneous contractions of the animals, and which were also easily excited at the pleasure of the observer, the body seemed to burn, becoming instantly like molten iron, with an extremely bright light ; but, as the phosphorescence again ceased, the colour of the animal passed successively through a number of extremely agreeable, light, and varied tints, such as red, yellow, orange, green, and azure blue, the last shade being extremely lively and pure.\n\u201c Left to itself in a glass of sea-water, the Pyrosome exhibited at regular intervals of time a slight alternating movement of contraction and dilatation. In these movements, the phosphorescence was seen to be developed during the contraction, then to grow insensibly feebler, and entirely disappear, until in the next contractile movement it was quickly re-established.\n\u201c By often irritating the animal, either by touching it or by shaking the water in which it floated, the phosphorescence could be excited and maintained for a much longer time. Evidently dependent on the organisation and the life of the individual, after death, as is the case with all other phosphorescent marine animals, it could not be reproduced.\u201d\nWe may remark that the observations made by Mr. F. D. Bennett *, who more than once met with shoals of P. atlanticum in lat 1\u00b0 4V N., long. 11\u00b056'W., and lat. 4\u00b0 8., long. 18\u00b0 W., differ but slightly from M. P\u00e9ron\u2019s notices of the same animal. The former observed, that when the specimens were taken in the hand from a vessel of seawater, the whole mass of the animal became instantly illuminated by myriads of bright dots, much resembling in hue the points on the wing-cases of the diamond-beetle ; and that the small specks of a brown or red colour, that were imbedded in the general tissue, and intermingled with the prominent, rigid, pearly tubercles, appeared to him to be the chief seat of the phosphoric light, frequently remaining bright, whilst the remainder of the body exhibited only its naturally white or yellowish hue\u2014a hue which changed after death into a red tinge. In making a close examination of the animal, Mr. Bennett remarked that no luminous matter was communicated from the surface of the animal to * Proceedings of the Zoological Society, 1833\nQ-nrl 1 \u00d6Q7\t\" 7","page":1229},{"file":"p1230.txt","language":"en","ocr_en":"TUNICATA.\n1230\nany fluid or solid in contact with it. But if the Pyrosoma were cut open and immersed in water, the brown particles that escaped diffused themselves through the fluid, and shone as numerous scintillations, independent of the perfect structure. General friction or contact was not essential to elicit the perfect light of the Pyrosome, since touching one small portion of the body was sufficient to produce a brilliant glow throughout the whole.\nMr. Bennett at the same time made the following observations on the effect of fresh water on phosphorescent marine animals. \u201c Fresh water appears to act as a powerful and permanent stimulus on marine Nocl\u00efluc\u00e6. Those that have intervals of repose from their phosphorescence immediately emit light when brought into contact with fresh water ; and this fact was strikingly exhibited in the Pyrosomata* When placed in a vessel of seawater and permitted to remain quiet, these Molluscs afforded no light, and, when touched, gleamed forth only as long as the irritating cause remained, and then gradually returned to their original state. When, however, the same creatures were placed in a vessel of fresh water, they never ceased glowing with their brightest refulgence until life was extinct, which was not until the lapse of several hours. When also the same Molluscs were mutilated, or so near death as to refuse to emit light upon irritation in sea-water, immersing them in fresh water produced at least a temporary revival of their brightest gleam.\u201d\nAnatomy of Salp\u00e6. \u2014 The subcartilagi-nous test of Salp\u00e6 is more or less cylindrical and flexible, and when taken out of the sea, often collapses into an amorphous mass. Floating in the water, it is iridescent or opaline, reflecting the sun\u2019s rays in beautiful rainbow tints, and hence has been derived its name of \u201c sun-fish.\u201d The test and its lining membrane are so diaphanous, that the whole structure of the animal can be seen through them. The exterior of the test is generally smooth, but sometimes bears minute shiny protuberances of a tissue similar to its own, as in S. Tilesii. The integument over the viscera is thicker and often of a firmer consistence than the rest of the test. Its form varies considerably, not only in different species, but in the conditions of isolation and aggregation, in which each species alternately exists, and also in the different stages of growth of the individual, especially in an associated state.\nThe test is usually either oval or oblong, but various terminal and lateral processes considerably affect its general contour. Each of its extremities is open by an orifice ; and, in the aggregated individuals, it is perforated by other much smaller apertures at the points of contact between the neighbouring individuals of a group.\nThe internal surface of the test is lined by the mantle, a thin, toughish membrane, which is often more conspicuous than the highly transparent external envelope. The mantle is furnished with large, generally transverse,\nmuscular bands, the arrangement of which differs according to the species and according to the separate or associated state of existence. Its inner surface is lined with a soft mucous coat of fine epithelial tissue. The mantle is more or less closely attached to the inner surface of the test, especially at the two orifices (being, indeed, continuous with the test at these points), at the protuberances that arise from the test, and along the inner surfaces of the longitudinal furrows that sometimes traverse its external surface, as in S. cordiformis, where, on the superior and inferior surfaces, the test is depressed into broad, deep sulci. In specimens preserved in spirit, and even in some recent specimens, this membrane will sometimes separate itself, together with the viscera and vessels, from the outer tunic, and fall through one of the external orifices. Salp\u00e6 have been met with floating in the sea, and executing, in some degree, their usual movements of contraction and dilatation; in which, from mutilations caused by parasites or other accidents, little remained except a few muscular bands of the mantle.\nConsiderable confusion has existed among naturalists as to which is the anterior extremity, and which the superior surface of the Salpa. We shall regard, as the anterior or branchial orifice, that in the neighbourhood of which the stomach and heart are usually found (fig. 787.); and as the posterior or anal orifice, that which points in the direction of the animal\u2019s retrograde motion ; and as the superior or dorsal surface, that on which the nerve-ganglion is present; and as the inferior or ventral, that in close contact with which the viscera and heart, forming the \u201c nucleus \u201d or \u201cpaquet \u201d of authors, are placed.\nThe orifices are either terminal, or are situated at the base of the terminal prolongations of the test. The anterior orifice is destitute of tentacular appendages ; it is furnished with sphincter muscles ; it is simple and tubular in S. cristata, S. Tilesii, and S. scutigera, &c., and transverse in S. cordiformis, S. zonaria, &c. When the dilatation of the animal is drawing water into the cavity of the body, the sphincters of this orifice are brought into action and close it, so that the water enters by the opposite extremity.\nThe posterior orifice is a transverse slit, furnished with a few muscular fascicles, and is larger than the opposite orifice. In S. cristata its superior lip is simple and thin ; its inferior lip is externally a rounded ridge, formed by a fold of the test, which, within its inner border, constitutes a semilunar valve. This allows the water to enter easily, but prevents its escape when the animal contracts itself.\nThe constrictor muscles of the mantle are often subannular, interrupted on one or the other surface, decussating in some, connected in others. The following are a few examples of the disposition of these muscular bands. In S. cristata, around the tubular anterior orifice, are 4\u20145 sphincter muscles ; the first of which, as well as the last two, are continuous","page":1230},{"file":"p1231.txt","language":"en","ocr_en":"TUNICATA.\t1231\naround the tube. The last two send lateral processes backwards, forming, with the succeeding band, the first on the trunk, and also annular, large rhomboidal meshes ; two other annular bands succeed and form large meshes by intercommunications on the upper and lower surfaces. From these last muscles two intercommunicating processes are sent off on each side to the crestlike prominence of the test. From the last band several branches run backwards to be distributed to the upper and lower lips of the posterior orifices.\nIn S. Tilesii the anterior orifice is provided with two lateral penniform muscles. The other muscles form six bands nearly parallel with each other, interrupted along the median line of the superior surface, and not reaching further than halfway down the sides of the body. The most anterior band is somewhat forked, and the most posterior gives some branches to the superior lip of the posterior orifice, and joins, at the angle of the lips, a radiating group of other fascicles, that are distributed to the inferior lip.\nIn S. scutigera the muscular bands are few. On the superior surface, two pairs of decussating muscles are seen, and other smaller bands occur near the extremities. In S. cy-lindrica there are eleven transverse bands, interrupted and separated by a considerable space on the inferior surface of the body ; the first six of which are parallel one to another, whilst the four following are bent towards each other on the median line of the body ; the last band, and some short lateral fascicles, are arranged close by the posterior extremity. In S. fusiformis there are seven transverse bands ; some of which are parallel with, and approaching others on the sides of the animal, and others are more or less obliquely arranged. In S. cordiformis there are six broad transverse muscles on each side of the animal, not meeting on either surface. Two narrow, looplike fascicles, one above and one below, arising from the last branchial bands, and two short, transverse, lateral slips, act as sphincters to the posterior orifice. A pair of narrow muscular fascicles are sent off from the first of the branchial muscles to the anterior orifice. In S. zonaria (the aggregate form or \u201c proles \u201d of S. cordiformis) there are also six transverse bands interrupted only on one surface, and differing considerably from those of S. cordiformis, as do the distinct sets of muscles distributed to the two orifices. In S.runcinata (solitary) (fig.772. a) the muscular bands are nine in number, placed on the dorsal surface ; three anterior and three posterior, approximated at their centres, and three parallel bands in the middle. In S. runcinata (aggregate) (fig. 772. b) there are six muscles, besides those of the orifices ; four anterior and two posterior, approximating on the median lines.\nThe branchia is single, in the form of a riband-like tube, stretched, on a vertical plane, obliquely across the central or branchial cavity of the body, so that it is constantly bathed by the water traversing this cavity. It consists\nof a double membrane formed by a fold of the internal tunic or mantle, and springs anteriorly from the visceral nucleus between the oesophageal opening and the orifice of the rectum ; it then becomes free, and ultimately terminates on the superior part of the thoracic cavity, below the point where the nerve-ganglion and the oculiform organ are found. It thus divides the branchial cavity into two portions \u2014 the antero-dorsal or pharyngeal, and the postero-ventral or cloacal.\nThe inferior border of the branchia exhibits an infinite number of minute transverse vessels, all parallel to each other. There is usually only a single row of these transverse vessels on each side of the foliole of the branchia ; but sometimes there are many rows, which indicate the presence of many longitudinal vessels, and thereby approach the character of the branchial tissue of the As-cidians.\nSavigny observed in S. octofora another small branchia near the anterior insertion of the large branchia.\nThe whole inner surface of the branchial sac of the Salp\u00e6 seems, from its high degree of vascularity, to be subservient to the purposes of respiration. The vascular tissue of the branchia, consisting of longitudinal and transverse vessels, is equivalent to the vertical branchial network dividing transversely the respiratory cavity of the Clavellin\u00e6.\nThe single branchial lamina of Salp\u00e6 appears to constitute the transition from the Ascidi\u00e6 to the Teredines; in the latter there are two elongated branchial laminae above the intestine, and within the tubular mantle, to which the water has access and egress by means of two tubes placed at the posterioi extremity of the body.\nThe intestinal canal is opaque, fuscous, or variously tinted, generally closely folded or convolute, and sometimes enveloped in the liver, forming altogether the \u201c visceral nucleus.\u201d This, together with the heart, lies external to the mantle, between it and the test. The oesophageal aperture is in the antero-inferior part of the body, behind the heart, more or less conspicuous and variously modified ; dissimilar in the alternate \u201c proles \u201d of the same species. In the solitary\u201c proles\u201d of S. pinnata and S. afi\u00eenis it is stretched above the branchia. In the aggregate \u201c proles\u201d pf S. pinnata it is opened out longwise, and of a violet colour in the living specimen.\nIn S. cristata the intestinal canal has the following characters. The oesophagus is round, with a loosely plicated margin ; the stomach has a contrary direction to the rest of the canal, being a cul-de-sac pointing anteriorly, and situated in the thickness of the antero-inferior protuberance of the test. It is membranous and transparent, and is described by Cuvier as ordinarily containing a little greyish fluid. The intestine is a simple tube having a direction unusual among the Salpians ; it runs from the stomach towards the posterior extremity of the body, where it opens into the branchial cavity by a rather","page":1231},{"file":"p1232.txt","language":"en","ocr_en":"1232\tTUNICATA.\nlarge anus. The faecal matter contained in it is greenish and vermiform. The liver (testicle, Krohn) in this species appears to be composed of large, parallel, longitudinal filaments, and terminates posteriorly in a delicate, tapering point. It differs also from the liver of other species in being of a whitish colour.\nThe intestine of the Salpians is usually twisted once or twice either around or within the liver, with the anus terminating nearly free of the latter, near the anterior attachment of the branchia. The anus is generally on the left side, opening posteriorly. The rectum never traverses the heart. In S. gibbosa and S. infundibuliformis the intestine makes a little more than one turn, the two ends crossing one another a little. It has two coeca, one on each side, which are turned into the centre of the loop of the intestine. Eschricht describes the liver of S. zonaria as conspicuous, enveloping nearly all the alimentary canal, and consisting of a mass of coecal tubes, each of which bear, near their free extremities and on one side only, a group of 2\u20146 minute, short coecal appendages.\nThe heart is with difficulty observed in dead specimens, but, from its pulsating movements, is generally conspicuous in the living animals ; and in these only can the circulatory apparatus be traced out. It is situated in the antero-inferior region of the body, near the visceral nucleus, the anterior attachment of the branchia, and the generative organs. It is a somewhat long, pellucid, tubuliform vesicle, enclosed in an immoveable pericardium. A longitudinal vessel or sinus (aorta, of Van Hasselt) traverses the inferior surface of the branchial cavity, and is continued into the inferior lip of the posterior orifice, and into the base of the posterior prolongation (if present) of the test. Hence it is retroflexed and recurrent. It gives off numerous branches at right angles on either side (fig. 787.) from which arise\nFig. 787.\nIk\nSalpa maxima ; showing the viscera and large vessels. The fine vascular net-work of the branchial sac is not introduced. (After Milne-Edwards.-)\na, upper lip of posterior orifice ; b, anterior orifice ; c, abdomen, containing the visceral nucleus ; d, branchial lamina ; e, heart ; f oculiform point ; g, g, prolongations of the test, by which the animal is adherent to its neighbours.\na great number of smaller branches, that subdivide, anastomose, and spread out in different parts of the body, forming a fine vascular network. All the transverse canals open into a large dorsal vessel, which thus receives all the blood which has passed through the\nvessels of the branchial sac ; but, besides this, some blood is also received by it, which has not passed through this tissue, in consequence of the great dorsal vessel being connected at each extremity with the great thoracic or abdominal vessel by two considerable annular vessels. The blood returns downwards from the dorsal vessel through a canal lying on the dorsal surface of the abdomen (dorsal canal) to the opposite end of the heart. The vascular net-work is very conspicuous in S. aspera, and is sometimes particularly distinct in the appendages. These ramifications go off from one another at right angles, and afterwards are, for the most part, bent back archwise, as Chamisso and Van Hasselt have observed ; so that, with the exception of those running transversely, all these little vessels have a direction contrary to that of the principal vessels ; that is to say, they are directed from behind forwards, whilst the aorta runs from before backwards. At the anterior extremity of the heart are two vessels, that answer to the pulmonary veins (dorsal sinus). They are equally distributed in the body of the animal, anastomosing with the branches of the principal sinus (aorta). The circulation of the blood among the viscera is carried on by means of variable interspaces occurring between these organs. The motions of the heart are made spirally, by a twisting of its parietes, and always begin from one or other of its extremities. As in other Tunicata, this action is oscillatory, having an alternately contrary direction, first impelling the blood in one direction, then stopping, contracting again, and soon impelling it in an opposite direction ; so that, after the blood has been flowing for some time from the heart to the aorta, to be distributed to the body, it stops, and then begins to run by the arteries and the aorta to the heart, and from thence, by the pulmonary veins and their anastomoses, it returns into the arteries and aorta. The contractions of the heart, in general very regular, diminish in rapidity at the approach of the periodic change in the circulation, the blood stopping, and even retreating a littl\u00e8 until a general contraction of the body determines it to take an opposite direction. The duration of the opposite circulation is not always the same. Van Hasselt saw the blood flow for three-fourths of a minute from the heart to the aorta ; and, during this time he observed forty-two contractions of the heart ; and he saw it reflow from the arteries to the heart and the pulmonary veins for a third of a minute, and in this interval he counted sixty-two pulsations.\nThe motion of the blood is the more perceptible as it is full of minute white globules, which pass through the minute vessels in a single row, and are easily seen through the transparent parietes. These observations maybe still more assisted by holding the animal vertically, with the nucleus downwards ; when, as the blood, driven into the ventral sinus, is forced to ascend against its own weight, its current is less","page":1232},{"file":"p1233.txt","language":"en","ocr_en":"TUNICATA.\t1233\nrapid, and the movements of the blood-discs can be more easily followed. \u201cAs these blood-globules are of a certain consistence, a resistance,\u201d says Van Hasselt, \u201c is necessarily created in the whole mass of the blood, which ultimately overcomes the projectile power of the heart. After a short interval, during which the opposite forces are balanced, the heart assumes a spiral movement, contrary to the preceding. Hence it follows,\u201d he observes, \u201c that, since the blood is driven as much backward as forward in the vessels of the body, and since it is only by their anastomoses that the circulation can be said to be carried on, all the system of the pulmonary vessels can consist only in accessory ramifications, which have no direct influence on the principal circulation ; and that two separate systems, arterial and venous, do not exist, the two being united, or rather never having been separate.\u201d*\nThe nerve-ganglion is more or less developed in all the Salpians. It is situated on the superior surface of the thoracic chamber, near the posterior extremity, and just above the insertion of the branchia. In its neighbourhood is often observed a pigmentary spot, or rudimentary organ of vision.\nIn \u00bbS', cordiformis the ganglion appears as a compound body, formed of two central globular portions and four irregular lateral appendages, two on a side. Numerous filaments radiate off in every direction. Four of these filaments are sent towards the posterior orifice, two of them passing on either side of the space described by Prof. Eschricht as the \u201c oval organ.\u201d This latter is a long slit with an inner smooth rim, and an outer oval, transversely striated border. In S. zonaria the ganglion is a somewhat triangular, globose body, with a single appendix on each side, sending off four anterior filaments, two lateral pairs and a posterior pair. The \u201c oval organ,\u201d situated between the last pair, is close up to the ganglion, and less distinct than in S. cordiformis.\nMany of the Sctlp\u0153 are highly phosphorescent f ; but sometimes this condition is due to the presence of phosphorescent Crustaceans inhabiting their internal cavity. The long chains of phosphorescent Salpce swimming near the surface, have been described as occasionally producing the effect of long ribands of fire drawn along by the currents.\nGeneration of Salpce. \u2014 \u201c One of the most important discoveries,\u201d saysM. KrohnJ,\u201cwith which physiology has been enriched in our days, is without contradiction that of the\n* Extrait d\u2019un Lettre de Van Hasselt, sur les Biphores, le 12 Ao\u00fbt, 1821 (Algem. Konst-en Let-terbode, 1822). Annales des Sciences Naturelles, tom. iii. 1824, p. 78. Bull, des Sciences, tom. ii. p. 212.\nf See Mr. G. Bennett\u2019s Observations on the Phosphorescence of the Ocean, \u201c Proceedings of the Zoological Society, 1837;\u201d and his \u201cWanderings in New South Wales.\u201d See also the Article, Luminousness, Animal.\nJ Observations sur le G\u00e9n\u00e9ration et la D\u00e9veloppement des Biphores. Annales des Sciences Naturelles, 3e s\u00e9ries, tom. vi. 1846.\nVOL. IV.\nremarkable phenomena observed in many inferior animals, and termed, * propagation by alternate generations.\u2019\u201d To M. Steenstrup* the merit is incontestably due, of having been the first to bring together, in an ingenious manner, all the facts belonging to the subject. In treating of the phenomena observed by Cha-misso in one species of Salpa, and analogous phenomena studied in other groups of animals, and in his generalisations of the facts, M. Steenstrup has placed them in a strong light, and given them their full value. M. Steenstrup\u2019s observations have also tended to strengthen the views of Ghamisso f so often contested ; and the researches of M. Krohn, on the natural history and zootomy of eight species of Salpce, fully confirm them. J Every Salpian is viviparous ; and each species, as shown by Ghamisso, is propagated by an alternate succession of dissimilar generations. One of these generations is represented by solitary or isolated individuals ; the other by aggregated or associated individuals, united into grqjups known as \u201c chains.\u201d Each isolated individual engenders a group of aggregated individuals, and each of these produces in its turn a solitary individual. The isolated individuals are therefore multiparous, and the associated individuals uniparous. This is not the only difference existing between the two alternating generations ; for, if we compare the associated individuals representing the aggregate generation, with the solitary individual forming the isolated generation, we shall find that they differ amongst themselves not only with respect to external conformation, but also in many particulars of organisation.\nThe definition, then, of species should in this case include the characteristics of the two dissimilar generations, isolated and aggregate, which alternately succeed each other. It is desirable therefore, for the determination of each species, to preserve but one name. This\n* Ueber den Generationswechsels in den Niedern Thierklassen, 1842.\n\u25a0f De Animalibus quibusdam a Classe Yermium Linnean\u00e2. Fase. 1. \u201cDeSalp\u00e2.\u201d Berolini, 18^9, 4to.\nJ M. Steenstrup, in his memoir on the Alternation of Generation (edit. Koy. Soc. pp. 39 and following), gives a full account of the different views of Chamisso, Meyer, and Eschricht, with regard to the development of the Salpce. He allots considerable space to the consideration of the arguments of the learned Danish professor, with whose opinions, however, he does not coincide, acknowledging that all his own researches tend to support the observations of Chamisso.\nM. Steenstrup notices that the alternate generations of Salpce are precisely analogous to the phenomena observed in the propagation of Medusa aurita. This free-swimming Medusa always produces a progeny which is polypiform and destitute of the power of locomotion, but which ultimately brings forth, by tissiparous generation, a progeny consisting of free-swimming Medusce, which never assume the polypoid form ; and this alternation is constant. M. Sars observes, on the generation of Salpce (Erichson\u2019s Archiv. 1841, t. i. p. 29.), that \u201c the Salpce correspond in this with the Medusae, that it is not their larvae which are developed into the perfect animal, but the progeny of the larvae ; it is not the individual, but the generation, which is metamorphosed.\u201d\n4 K","page":1233},{"file":"p1234.txt","language":"en","ocr_en":"TUNICATA.\n1234\nmust comprehend the two dissimilar states which have hitherto been falsely considered as two distinct species, and to which have been given specific names, that can now serve only to designate one or the other of the hetero-morphous conditions.*\nAmongst the characters that distinguish the different generations of each species of Salpa, one of the most remarkable is offered by the disposition of the muscular bands. These are variable in the two generations, but constant for each of them. There is, however, a still more essential difference, and that is, the mode of propagation peculiar to each generation. The aggregate individuals proceeding from the isolated individuals grow by gemmation within the mother animals, on a cylindrical prolongation, which may justly be termed a proliferous| stolon, but which differs from stolons observed in many other animals, in not ever appearing externally.\u2014 The stolons of the \u201c social \u201d Ascidians spring up bare, the animal not being connected by a common gelatinous envelope, as is the case with the \u201ccompound\u201d Ascidians; in which latter group the stolons necessarily remain hidden in the common envelope, somewhat approaching in this respect the stolons of the Salpians.\nThe solitary Salpians derived from the aggregate generation are, on the contrary, produced by a process more complicated namely, by means of the sexual functions,\u2014the concurrence of the eggs and the sperm.\nGeneration in the \u201caggregate\u201d Salpians. \u2014 With very few exceptions, the individual aggregate Salpians produce only one offspring throughout their lifej:, so that, if we examine them at one period, anterior to fecundation, we find a single egg, and, at a later period, a foetus. The egg is distinctly visible within the young aggregate individual before it has left its parent (isolated) Salpian ; and\nas the fecundation of this egg takes place immediately, or at least a very short time after, the birth of the young aggregate Salpa, it can be examined before fecundation, that is, during the development of the aggregate Avithin the isolated individual, or shortly after its birth. The egg is lodged in the thickness of the internal tunic of the mother, at a little distance from the inner wall of the respiratory cavity. It is very clearly distinguishable in the aggregate embryo at a period intermediate between the appearance of the solitary embryo as a bud and its full development. It is then situated above the visceral mass, at the anterior extremity of the body, and nearly in the middle line, raising the external tunic into a slight prominence. It is spherical, and consists of a vitellus, containing the germinal vesicle and spot, and invested with a membrane so thick, that M. Krohn is led to regard it as comparable with the \u201c calyx\u201d in birds. During the progress of the development of the animal, the position of the egg is altered, and it becomes situated on the side of the body, somewhat approaching towards its superior surface, and behind the second muscular band. This position is retained by the egg, and subsequently by the foetus.\nTo the posterior extremity of the egg a cord is attached, which serves as a sort of peduncle, in general directed nearly horizontally backwards, and consisting apparently of a prolongation of the membrane that covers the vitellus. At the period when the egg occupies the anterior extremity of the embryo, this cord is proportionally thicker and shorter than at the subsequent periods of the embryo\u2019s development. M. Krohn considered it as being the nutritive peduncle of the ovarian capsule, or membrane, enveloping the egg. This cord exists, as above described, up to the time of fecundation, but it soon afterwards disappears. The ovary, we see, is\n* To the above observations, M. Krohn has added the following list of such species of Salpa as he had been enabled to recognise in the two states : \u2014\n\u201e\tIk the Solitary State (Proles solitaria\nSpecies.\tChamisso).\n. f Salpa democratica, Forskahl \\\n'\t\\ S. spinosa, Otto\tj\n2.\tSalpa africana, Forskahl\n3.\tSalpa runcinata, Chamisso -\n4.\n7.\nIn the Aggregated State (Proles gregata, Chamisso).\nf Salpa mucronata, Forskahl.\n\\ S. pyramidalis, Quoy and Gaimard. f Salpa maxima, Forskahl.\n\"[ S. Forskahlii, Lesson.\n{Salpa fusiformis, Cuvier.\nS. maxima, var. prima, Forskahl.\nS. runcinata, gregata, Chamisso.\n- Salpa punctata, Forskahl.\nSalpa, observed by Krohn -Salpa scutigera, Cuvier S. vivipara, P\u00e9rou and Lesueur S. gibba, Bose\nS. dolium, Quoy and Gaimard Salpa, observed by Krohn\n(Salpa cordiformis, Quoy and Gaimard -\t| g^polycradca^ Forskahl.\nj The recognition of the two forms of this species was made by Prof. Eschricht, and con-' firmed by M. Krohn.\nf Salpa bicaudata, Quoy and Gaimard. ( S. nephodea, Lesson.\nSalpa proboscidalis, Lesson. f Salpa zonaria, Chamisso.\n\n( Salpa Tilesii, Cuvier. j S. infundibuliformis, Quoy and Gaimard.\n( Salpa costata, Quoy and Gaimard )\nI Dagysa strumosa, Banks\tj\nM. Krohn observes also, that Salpa ferruginea, Chamisso ; S. conf\u00e6derata, Forskahl ; S. socia, Bose ; S. octofora, Cuvier (?); S. bevis, Lesson, and S. femoralis, Quoy and Gaimard, do not materially differ from S. bicaudata.\nf Professor Eschricht was the first to recognise J S. zonaria is the only example of an aggregate the true signification of this part.\tSalpa producing several (four) foetuses.","page":1234},{"file":"p1235.txt","language":"en","ocr_en":"TUNICATA.\n1235\nrepresented merely by the membrane that surrounds the egg, and which, as before remarked, may be compared to the calyx of birds. The testicle, on the contrary, is well developed, but, not increasing in bulk in proportion to the growth of the young Salpa, it only acquires its greatest development in nearly adult animals. It is always found in the neighbourhood of the intestine, but its position varies in different species. Sometimes occupying the centre of the visceral mass or nucleus, formed by the intestinal loop and its appendages, its presence is evident only in proportion as it raises those parts ; sometimes showing itself quite exposed, it more or less covers a large portion of the digestive apparatus. This organ in the aggregate form of Salpa pinnata, S. pro-boscidalis, &c. is spindle-shaped, and rests against the intestine, and has been taken for the liver by Cuvier, Chamisso, and Meyen. The testicle is composed of a greater or less number of ramified canals, the last ramifications of which end in culs-de-sac. All these canals end in a principal duct, which, passing along the terminal portion of the intestine, opens at the side of the anus in the great natatory or respiratory cavity traversing the body of the Salpa.\nThe testicle is very much slower in its development than the egg organ in these animals ; and, as young aggregate Salpians are met with in which a fecundated egg and undeveloped testicle are co-existent, these individuals must have had connection with others in which the development of the latter organ was further advanced ; the sperm that fecundated the eggs being supplied by another group of animals. The maturity of the sperm does not coincide with that of the egg, yet, as the two sexual organs are present in the same body, these animals are hermaphrodite, although probably not self-impregnating. They have two generative functions to perform : the one to produce a new being, the other to fecundate an ulterior generation of animals similar in all respects to themselves. The \u201c aggregate\u201d Salpians probably perish soon after they have given birth to their \u201cisolate\u201d offspring.\nThe placenta, or attachment of the f\u0153tal \u201cisolate\u201d in the \u201c aggregate\u201d Salp\u0153.\u2014The embryos of the Salp\u0153, undergoing all the phases of development within their mother, adhere to her by the aid of an organ, the use of which is to furnish them with the necessary nutritive elements. These elements being derived from the blood of the mother, the vessels of the latter enter largely into the composition of this organ. Its structure and form vary much according to the mode of propagation peculiar to each generation. The propagation in the \u201cisolated \u201d Salpians is by gemmation, and here the organ in question is the proliferous stolon. In the \u201c aggregate \u201d Salpian, on the other hand, this organ is represented by a body generally round, situated on the inferior surface of their single f\u0153tus, and fixed to the\ninternal wall of the maternal cavity,, precisely in the position occupied by the egg, and to this organ many naturalists have with reason attributed the functions of a placenta. This nlacenta is ordinarily situated in the external tunic of the f\u0153tus; its structure is far from being well known. In appearance it is a soft, whitish, or brownish pulp, traversed by numerous vessels ; it is attached by a very short pedicle, which is formed by a prolongation proceeding from the inner tunic, and enveloping this organ. The vessels distributed in the interior of the placenta communicate with four trunks, two of which communicate with the vascular system of the f\u0153tus, and the other two with that of the mother. Those of the f\u0153tus, in descending towards the placenta, traverse the peduncle ; the one conducting the blood to this organ, and the other returning it to the f\u0153tus. The two maternal trunks have analogous functions ; they terminate at the point where the placenta is attached to the mother. Each of these f\u0153tal and maternal trunks alternately act as arteries and veins. This alternation is due to the periodic changes that determine the contractions of the heart in Tunicates generally. The vessels of the foetus and of the mother are not in direct communication ; but, as in Mammalia, they are merely contiguous. M. Krohn\u2019s microscopical observations also tend to prove that the maternal blood never commingles with the f\u0153tal blood. The blood-corpuscles of the f\u0153tus are distinguishable from those of the mother by their less size and by the more constant regularity of their forms.\nThe develppment of the placenta commences at any early stage of enbryonic life, and in its progress corresponds to that of the f\u0153tus. Ultimately the placenta becomes detached from the maternal tissues, and is carried away by the young born animal. It remains for a long time in connection with the young animal, but decreases rapidly in size, and ultimately disappears before the full growth of the animal is perfected.\nEleoblast of the foetal Salp\u0153. \u2014 There is another organ belonging to the f\u0153tus, mentioned by authors, especially Chamisso, Me} en, and Krohn, which is a round whitish body, lodged, like the placenta, in the external tunic of the f\u0153tus. Its use is entirely unknown. It appears to be composed of a multitude of fascicles or lamellae, that, by their intercrossing with one another, circumscribe cellular cavities, filled with a perfectly clear oily liquid, composed chiefly of globules. The fascicles or lamellae are traversed by numerous vessels opening into two trunks, which apparently form the attachment between this organ and the visceral nucleus. Meyen thought it to be the vitelline sac of the f\u0153tus ; but, according to M. Krohn, this opinion is inadmissible, because the \u201c aggregate \u201d embryos, which we know are not produced from eggs, are provided with it. This body, M. Krohn terms the \u201celeoblast.\u201d During the incubation of the f\u0153tus, and after\n4 k 2","page":1235},{"file":"p1236.txt","language":"en","ocr_en":"1236\tTUNICATA.\nthe birth of the individual, the changes of volume undergone by this organ correspond in general to those of the placenta ; but its decrease proceeds more slowly, and its remains are observable long after the placenta has disappeared.\nDevelopment of the foetal \u201c isolate \u201d Salp\u00e6. \u2014 The development of the foetal \u201cisolate\u201d Salpa occupies a considerable time, not being accomplished until the mother has almost attained her full growth. Of the progress of the genesic phenomena, there is as yet but little clearly known. The first changes manifest in the egg after fecundation, are the early disappearance of the germinal vesicle and spot, the increase of the egg in size, and the loss of its ovular, and assumption of a spherical, form. Soon afterwards the egg, so transformed, is replaced by a round body, which raises the internal tunic of the mother into a slight nipple-like prominence, projecting into the internal cavity of the latter. This is the rudimentary placenta, and is channelled by a cavity which is in direct communication with the two maternal vessels previously spoken of. These vessels are at this period very minute, but they quickly increase in size. By their means a current of blood is already established in the interior of the rudimentary placenta. The maternal blood carried by one of the vessels of the cavity rises on one side towards its base, and then, describing an arch, descends on the other side, to return to the mother by the opposite vessel. The first rudiment of the foetus is, it seems, developed after the appearance of the placenta. It is at first a very minute body, formed, on the summit of the placenta and under its envelope : this covering is a continuation of the internal tunic of the mother, and becomes, at a later period, the external tunic of the foetus. The organs soon appear in the rudimentary embryonic mass. The respiratory cavity, M. Krohn observes, is, probably, one of the first parts formed, the foetus, previously solid, becoming evidently hollow ; immediately afterwards the rudiments of the brarichia and the nervous ganglion are perceptible ; the visceral nucleus, the eleoblast, and the heart become distinct only at a late period. When the eleoblast is developed, it is placed anterior to the visceral nucleus, and the heart then begins to contract, although feebly. It is only when the foetus acquires a better determined form, that the two orifices of the body become visible, the posterior at an earlier period than the anterior. The foetus now surpasses the placenta in volume, although the latter has not, since its appearance, ceased to grow ; and the nervous ganglion, distinguishable from all other parts by its rapid growth, is conspicuous from its volume, compared to that of the other organs, and gives origin to numerous nerve-filaments. The eleoblast, the volume of which is considerably increased, tends to place itself below the nucleus. It is at this period also that we can clearly distinguish the muscular bands, although in a yet imperfect state. Each band is represented\nby two lateral symmetrical portions, separated one from another by a large interval along the superior surface of the body ; it is not until a later period that the two portions are united into a single band. The placenta also exhibits a marked change. The cavity that it contained disappears, and its place is occupied by the pulpy w hitish substance before spoken of. At a more advanced stage, but still far from the full term of development, the foetus presents a form that subsequently is but little altered. Its volume, compared with that of the placenta, is greater than before. The eleoblast, as yet less than the placenta, is now placed behind it, and soon equals it in size. The distribution of the vessels on the different parts of the foetus is become more apparent ; and the two trunks enclosed in the peduncle of the placenta are distinguishable. Now also the contractions of the heart may be seen to change their direction periodically, the blood consequently circulating in the same singular manner as in the adult Salpians. But another still more remarkable phenomenon manifests itself at this period, viz. the precocious formation of the stolon proliferum, which springs from near the heart, in the form of a little button.\nDuring the later periods of development, the resemblance of the foetus to the adult becomes more marked daily, as well as its increase of volume compared with the placenta. The foetus, which in the last period referred to already showed some indication of spontaneous movement, commences to alternately contract and dilate its body, like the adult animal. These movements, feeble at first, are before long, as the animal approaches its full term, executed with considerable vigour. The foetus being attached to its mother, these movements cannot displace it ; and their only end, without doubt, is to draw towards it the supply of water necessary for its respiration. As regards the stolon proliferum, its growth during all this time is so slow, that, even at the time of the birth of the animal, it is but a short, delicate filament. Nevertheless, on a close examination, there may be perceived on its surface a serrated edge of minute elevations, indicating the first vestiges of the buds that will subsequently be developed into embryos.\nGeneration in the \u201c isolate \u201d Salpians. \u2014 The \u201c isolate \u201d Salpians are, as we before mentioned, gemmiparous, and have their young produced on a small pedunculated organ, the stolon proliferum, which is visible within the single f\u0153tus whilst still contained within its \u201c aggregate \u201d mother. It then exists as a very slender short filament, but already gives indications of buds upon its surface. After the birth of the animal, it increases in size in proportion to the continually increasing number of buds that spring from it. It is fixed by one of its extremities to the heart of the mother : and it is alw'ays at this extremity that the stolon produces new germs. The growth of the buds, just as the nutrition of the embryos, being entirely dependent on the blood of the","page":1236},{"file":"p1237.txt","language":"en","ocr_en":"TUNICATA.\n1237\nmother, the stolon is constructed to admit a proportional quantity of the vital fluid. Two vessels traverse it throughout its length, one proceeding from the anterior extremity of the maternal heart, and the other from the opposite end. Hence the blood, forced into one of these vessels by the contraction of the heart, returns by the other ; and at each time the heart commences to contract in an opposite direction, the two vessels quickly coincide in the change. M. Milne Edwards has demonstrated that the proliferous stolons of the social and compound Ascidians are likewise traversed by two similar vessels, one of which has an ascending current of blood, and the other a descending current. In examining the stolon at a more advanced period of its growth, one may embrace at a view, owing to the successive germination of buds, the complete series of the phases passed through by each embryo, from the time of its first appearance in the form of a little button, to the full term of its development (fig. 788.). The\nFig. 788.\nSalpa zonaria (aggregate) in its f\u0153tal state. Magnified about 4 times. (After Eschricht.')\na, b, part of the first set of the young Salp\u00e6 ; e, d, the second set ; e, f, the third set ; g, the stem with its germs ; h, h, the anterior orifices ; i, i, viscera ; j, j, ganglia ; k, k, posterior orifices ; l, vessels ; to, muscular bands of the branchial sacs.\nphases passed through by the different organs correspond to those that the same organs present during the development of the \u201c isolated\u201d foetus.*\nDevelopment of the f\u0153tal \u201caggregate\u201d Salp\u00e6 ivithin the \u201csolitary.\u201d \u2014 Whatever may be the mode of aggregation of the associated Salp\u00e6 at the adult age, their germs are always disposed in the same pattern along the stolon in two parallel rows, so that the germs alternate one with another. It necessarily follows that the embryos during growth must be arranged in the same manner. The embryos are always placed in such a manner that the axes of their bodies cross the axis of the\n* The development of the foetal \u201caggregate\u201d Salpians is beautifully illustrated in the fourth and fifth plates of Prof. Eschricht\u2019s Paper on the Salp\u00e6, in the Royal Trans. Copenhag. vol. viii. 1841.\nstolon at a right angle : they adhere among themselves by means of their organs of attachment. The development of the \u201c isolate,\u201d like that of the \u201c aggregate,\u201d f\u0153tus proceeds but slowly : the growth of those foetuses that spring from the first-formed germs is not terminated until after the mother has almost attained her full age. It is easily conceived that, as the number of buds continues to augment during all the time the mother grows, the form of the germs and the embryos, or the embryonic chain, acquires lastly a considerable length. Lodged in the external tunic of the mother, and adhering to the heart of the latter by the aid of the vessels of the stolon, this embryonic chain sometimes passes directly backward, and terminates before reaching the posterior extremity of the body, as in the isolated generation of Salpa pinnata and some allied species : sometimes, as in most other species, it curls itself around the visceral nucleus, describing several spiral turns, and terminates at the anterior extremity of the body. If we examine the embryonic chain at this period, we may observe three very distinct groups of embryos (fig. 788.). The proximal group (f e) is made up of the germs and of the embryos, as yet but little developed, that succeed them. These present a progressive series of the early phases of embryonic development ; but the next group (id, e) is composed of embryos much further developed, and these being nearly all of the same size, offer but a slight trace of gradation. The distal group of embryos (b, a) having arrived almost at their full growth, present no great difference among themselves. The embryos, products of the same stolons, leave the mother in groups, and the group most developed is necessarily the first to be born. The perfect uniformity in the size of the newly born individuals explains also why the animals of Salpa-chains are all of the same size and form. The embryonic chain of S. pinnata, however, and allied species, never presents these distinct groupings. Here, on the contrary, the phases of development proceed regularly, following the order of progression throughout the chain. Hence the newly born animals, grouped in a circle, are often somewhat unequal in size ; but this irregularity soon disappears.\nThe embryonic chain, as we have seen, is lodged in the external tunic of the mother. During the earlier periods of its growth, the substance of the tunic envelops it so closely, that no interval is apparent between them ; but, as the mass of embryos increases in size, there is formed around it, and chiefly around the most fully developed group of embryos, a cavity which is prolonged towards the surface of the mother\u2019s body, and opens externally by a large orifice. By this orifice the embryos, when mature, make their exit. The position of this opening always corresponds with the point where the embryonic chain happens to terminate, which is sometimes near the anterior extremity, but sometimes even at the posterior extremity of the body of the\n4 k 3","page":1237},{"file":"p1238.txt","language":"en","ocr_en":"1238\nTUN IC ATA.\nmother. At the moment of the birth of a set of embryos, they detach themselves from that part of the stolon which supported them, and it then withers and disappears.\nThe embryos, as we have seen, are placed along the stolon in such a manner, that the axes of their bodies cross the axis of. the stolon at right angles. This original position of the individual either persists from birth throughout life, or is changed, accordingly as the new-born animals belong to one or other of the three types of aggregate form to which the associated Salpes are hereafter referred. In the associated Salp\u00e6 of the first type, the relative position of the individuals remains such as it was at birth. In the Salpians of the third type, however, a change of position of the young individuals is very manifest, for the form of the generality of these Salpians is not quite perfected at birth. The two pyramidal processes with which the bodies of S'maxima and S.fusiformis are furnished, are but slightly developed in the newly born animals. The growth of these prolongations during youth is accompanied with marked changes' in the position of the respective individuals of the group. When these processes are but small, the body of the animal is slightly inclined to the axis of the chain. This direction becomes the more oblique as the two rolongations increase ; and lastly, when they ave attained their full growth, the animal is perfectly parallel to the axis of the chain ; and now the development of the \u201caggregate\u201d Salpian is accomplished.\nMode of arrangement and attachment of adult \u201c aggregate\u201d Salp\u00e6. \u2014 Each group of aggregate Salp\u00e6 is composed of a greater or less number of individuals of the same size. Sometimes the individuals are grouped in a simple circular series around a common axis, as in S. pinnata, and some allied species. Sometimes the individuals are arranged one after another in two longitudinal, parallel series, and so disposed that the individuals of one series alternate with those of the opposite series (fig. 772. c). The biserial aggregation presents numerous variations, according to the diversities and forms peculiar to the associated individuals of different species. In these diversified modes of assemblage, M. Krohn points out three types, to which all the variations are reducible. The first is characterised by the vertical position of the animals forming the chain, so that the axes of then-bodies cross the axis of the chain at a right angle (Sa/pa bicaudata, S.ferruginea). In the second type the bodies of the individuals are more or less inclined to the axis of the chain {S. mucronata, S. Tilesii). The third group is distinguished by the horizontal position of the component animals, the axis of their bodies being more or less parallel to the axis of the chain (S. maxima, S. fusiformis, S. punctata, S. zonaria).*\n* Meyen also made an analogous distribution of the aggregate Salpians. Vide Nova Acta Nat. Cur. tom. xvi. \u201c Supplementum.\u201d\nIn each group the individuals are in such close approximation, that there exists no interval between them, and the entire group appears as one mass. The individuals touch one another by the inferior surface, and more or less also by the lateral surfaces of their bodies. The superior surface, that where the nervous ganglion is situated, and the two orifices, remain perfectly free. Thus, for example, in a chain in which the individuals are disposed vertically or obliquely to its axis, the members of each rank are united to those of the opposite rank by their inferior surfaces, and to their collateral neighbours by then-lateral surfaces. But, however closely the individuals may adhere one to another, mutual contact of the surfaces would not have been sufficient to maintain their juxtaposition, had not other appliances been furnished. There are sometimes appendages of considerable size, sometimes small protuberances, or only circumscribed points of the surface of the body, by the aid of which the animals adhere among themselves so strongly, that they can rarely be separated without some effort. These special organs and facets of attachment have been very incorrectly regarded by some authors as suckers. Their number varies according to the mode of aggregation. The associated individuals of Salpa pinnata and allied species, grouped in a circle, are provided with only a single large appendage, springing from the inferior surface of the body, and resembling sometimes a crest (S. pinnata), sometimes a horn (S. proboscidalis). The individuals, few in number, are united by the extremities of these appendages, which meet one another in the centre of the group. The organs of attachment of Salp\u00e6 aggregated in chains are protuberances and facets, generally about eight in number. Four are placed in pairs on the inferior aspect of each animal, and serve to unite it to its two neighbours in the opposite series ; of the two other pairs, one pair occupies one of the lateral faces, the other the opposite lateral surface, uniting the individual to its two collateral neighbours. The position of these organs varies according to the form of the associated individuals, and accordingly as they belong to one or the other of the above mentioned t\\pes. Of these appendages we may notice the two prolongations of the body common in most of the aggregate forms ot the third type, as in S. maxima, S.fusiformis, and chiefly by means of which the contact of the individuals is preserved. Both are pyramidal in form, and arise one from the anterior and the other from the posterior extremity of the body.\nWe will here remark that an individual cannot spontaneously separate itself from the group of which it forms a part. It is true that free individuals are often met with, but their separation is always due to some accident. M. Krohn thinks even that the union in groups is so necessary to the maintenance of the life of each animal, that it soon perishes if by chance it becomes detached.","page":1238},{"file":"p1239.txt","language":"en","ocr_en":"1239\nTUNICATA.\nAnatomy of Pelonaia.*\u2014 Muscular system.\u2014 The mantle is similar to that of other Tunicates, possessing longitudinal and circular fibres ; the former in P. corrucala forming a thick bundle at their origin round the respiratory opening. A strong band of transverse fibres passes round it, in one species, immediately below the anal orifice, encroaching on the cavity principally on that side. The chief peculiarity of the mantle is its firm adhesion to the test.\nFig. 789.\nAnatomy of Pelonaia glabra. {After Forbes and Goodsir.')\na, a bristle inserted into the respiratory sac through the oral oritice ; b, a bristle inserted into the mantle cavity through the anal oritice of the test ; c, ganglion, with the nerves proceeding from it ; d, the shelf, or transverse ridge, in the interior of the test and mantle ; e, branchial vein, enclosed in a serpentine band, as in some of the other Asci-dians ; /, branchial artery ; g, generative organ on the left side, with a bristle inserted into its duct ; h, the stomach ; i, anus ; k, k, cut edge of the test.\nDigestive and respiratory systems. \u2014 The respiratory opening is of small size, and exhibits no folds or tentacular fringes. The respiratory sac is elongated, cylindrical, contracting rather suddenly towards one side to become continuous with the oesophagus. On the external surface of the sac there are about thirty parallel transverse ridges, which give it the appearance of a plaited frill. These plaits are less apparent along the course of the\n* From Forbes and Goodsir, loc. cit.\nbranchial artery and vein, but midway between them on each side they are very prominent, and are tied, each by a minute cord, to the inner surface of the test. The internal surface of the sac exhibits along one side the serpentine double cord which contains the branchial vein ; along the other side the branchial artery ; and from these primary and secondary perpendicular branches proceed, as in other Tunicata. The transverse plaits on the external surface of the sac correspond to the primary or transverse branches of the vessels on the internal surface. During the life of the animal, without doubt, cilia exist in great abundance on the edges of the lozenge-shaped spaces of the sac.\nThe oesophagus commences by a white plicated opening at the lower end, and on one side of the sac (fig. 789.). It is curved in a sigmoid form, and exhibits longitudinal rugae through its coats. Near the lower end of the mantle-cavity it terminates by suddenly dilating into the stomach (h), which is pear-shaped, and directed obliquely upwards towards the side opposite to the oesophagus. The internal surface of the stomach presents longitudinal plicae. It is succeeded by the intestine, which at first curves upward, and then down to the bottom of the branchial cavity, up along the oesophageal side of that cavity and between its walls and the branchial artery, terminating about the anterior third of the animal in a funnel-shaped anus (i), which is cut into ten or eleven processes, like the petals of a flower. The first part of the intestine is white, and longitudinally plicated ; the rectum is dilated, and its coats are attenuated.\nVascular system. \u2014 The vascular system resembles that of the Ascidiad\u0153, except that there is no heart. It consists of two sets of vessels, with four sets of capillaries ; a circle in fact twice interrupted, once in the respiratory sac, and again throughont the body. The branchial veins run along the transverse plaits of the sac, receiving secondary and ternary twigs at right angles. The primary branchial venous branches empty themselves on each side into the branchial trunk, which runs in the substance of the double cord which coasts the superior aspect of the sac. This double cord terminates in an abrupt manner anteriorly near the oral orifice, and in a similar manner, but often becoming smaller near the orifice leading to the oesophagus. At this point the vein becomes an artery, and probably sends back vessels to nourish the sac. It now runs along the oesophagus, supplying the stomach and intestine, and giving off in its course branches to the mantle. The veins arising from the arterial capillaries of the body meet near the commencement of the oesophagus in one trunk, which, passing along the inferior wmll of the respiratory sac, opposite to the branchial vein, performs the functions of a branchial artery. It is interesting to observe here the differences between the modes in which the branches enter the branchial vein, and strike off from the branchial artery. In the former, just before the\n4 k 4","page":1239},{"file":"p1240.txt","language":"en","ocr_en":"1240\tTUNICATA.\nbranches enter the trunk, they give off a number of vessels, which enter a trunk alongside of the parent trunk, the combination forming a sort of delta ; in the latter, they leave the trunk singly, and send off their branches in a radiating direction. At a little distance from the trunks of both artery and vein, the secondary branches become parallel to one another and perpendicular to their primary branches, the more minute divisions following the same mode of ramification.\nNervous system. \u2014 This system consists, as in other Tunicates, of a ganglion situated in the substance of the mantle, between the oral and anal orifices. It is globular, and sends off nervous twigs, firstly, to the respiratory orifice of the mantle ; secondly, to the respiratory sac, where it begins to exhibit the transverse plates ; and thirdly, to the anal orifice of the mantle.\nGenerative system. \u2014 The generative organs consist of two elongated tubes, closed at one end, open at the other, and having a great number of close-set parallel c\u0153ca arranged at right angles, and opening into them along each side. These tubes are attached to the internal surface of the mantle ; their mouths are free for a short distance, and prominent the rest of their extent, and the attached cceea adherent. The orifices of these organs are situate at the junction of the first with the second quarter of the animal, and one third of the other end of each turns in towards its neighbour, and then proceeds forward parallel to itself. The branchial vein runs midway between the generative tubes above, and the branchial artery in a corresponding course below, so that the threads of the attachment of the plaits on the external surface of the sac are fixed into the tubes in a series on each side.\nFrom the details of the structure above given, it is evident that the Pelonaia is a true Tunicate. Its anatomy is important, and assists in the elucidation of the nature of the parts and organs in other members of the group. They present the positive anatomical character of a union of the mantle with the test ; so that there can be little question of their right to be regarded as members of a distinct family of Tunicata ; and it is worthy of notice, says Prof. Forbes, that Mr. MacLeay, in his valuable remarks on the arrangement of the Tunicates (Linn\u00e6an Transact, vol. xiv.) had hypothetically indicated such a group as this now constituted. Whilst in many of their characters they approach the true As-cidians, especially the unattached species of the genus Cynthia, in others they indicate a relationship with the cirrhograde Echinoder-mata. They differ from their Tunicate allies chiefly by their not being fixed, and by their form, which reminds one more of that of a Siphunculus than of an Ascidia ; indeed, they may be regarded as analogous to certain Siphunculid\u0153 ; and in that point of view the details of their form and structure are of much interest to the naturalist. They differ also, add Messrs. Forbes and Goodsir, from\nthe Aseidians, more particularly in being bilateral. The generative organs are symmetrical, and open one on each side of the anus, which is directed towards the ventral surface of the animal, in a line with the mouth and the nervous ganglion. The latter is thus proved to be an abdominal or suboesophageal ganglion, corresponding to or forming one of the chains of ganglia on the abdominal surface of the Articulata. In the same manner, the branchial artery or heart is proved to be the pulsating dorsal vessel, and the branchial vein the abdominal vessel (when that vessel exists) in the Annulosa. It is interesting also to perceive, that, co-existing with this decided approach to the annular type of form, we have the transverse plaits of the respiratory sac corresponding to the rings of an articulated animal. The disappearance of a separate test is also a departure from the plan of formation in the Ascidiad\u0153 and their allied groups, and an approach to other types of form, and more particularly to the cirrhograde Echinoderms, with certain of which Pelonaia has at least an analogical relation, in the water-filled body, and in the external form.\nPelonaia, in fine, is one of those connecting genera so valuable as filling up gaps in the system, and supplying links in the chain of structures which runs through the series of organised bodies.\nLocomotion of Tunicata.\u2014 Generally speaking, the muscular tissue of the Ascidiad\u0153, Botryllid\u0153, and Pelonaiad\u0153 is not subservient to the purposes of locomotion, and merely effects the sudden removal of water and noxious objects from the branchial sac. The entrance and exit of water through the external orifices, constituting the chief sign of vitality in these apathetic creatures, are generally caused by the ciliary currents.\nBut the water may be driven out by an ejaculatory effort of the constrictor muscles of the mantle ; which action would be followed by a more or less rapid expansion or dilatation of the mantle and test, effected by the elasticity of the latter. In such species as occasionally occur unattached, or even floating about freely, such an ejaculatory action would effect a transitory retrograde movement ; but we have no evidence that any of the Ascidiad\u0153 or Pelonaiad\u0153 make use of this propulsive agent in the manner of the Pyro-somata and the Salp\u0153. Nearly all the Ascidiad\u0153 and Botryllid\u0153 are sessile, but some few, mounted on flexible pedicles as Boltenia and Sigillina, may be said to enjoy a limited freedom of movement, necessary perhaps to their well being ; and the same may be said of such species as are attached to the floating branches of flexible alg\u00e6 and corallines.\nAccording to Mr. F. D. Bennett, except in the action of the sphincter-like membrane, surrounding the open extremity of the compound cylinder, there was but very slight evidence of motive power in the specimens of Pyrosoma examined by him. MM. P\u00e9ron and Lesueur, however, describe a slight retrograde motion observable in this animal. The","page":1240},{"file":"p1241.txt","language":"en","ocr_en":"TUNICATA.\n1241\nmethod in which this is brought about is not very clear ; it appears to be caused either by the synchronous contraction of the individual animals, causing a diminution in the general calibre of the cylinder, and thus effecting a faint ejaculation of water from the cavity of the latter ; or by the posterior current of water from the anal orifice of each animal being synchronously ejected into the cavity of the cylinder, and thus giving a motive power to the whole.\nWe have a more decided locomotion exhibited in the Salpa, which is treated of by Mr. Bishop* as a \u201c syringograde\u201d animal, in the same category as \u201c the Holothuria, and the larvae of those insects whose progression is effected by the alternate reception and expulsion of water to and from their respiratory organs by an action similar to that of the syringe.\u201d In Salpa the dilatation of the test and its membranous lining causes the water necessary for respiration and nutrition to enter through the bilabiate posterior orifice, which has a valve preventing the return of the water by the same aperture f; a transverse contraction of the body then expels the water through the anterior orifice, and the result is, that the animal is forced backwards, being carried in an inverse direction to that of the ejected water. J This retrograde motion\n* See art. Motion, Vol. III. p. 433.\nj- See figure of Salpa cristata, showing most of the branchial muscles and the position of the valve (the latter is ideal, not being visible externally in the animal), fig. 228. p. 434. Vol. III.\nJ In a communication from my friend Mr. Pittard on the subject of Syringograde movement, he remarks as follows : \u201cI am not aware that a true and satisfactory explanation has ever been given of the backward motion of bodies resulting from the ejection out of them of jets or currents of fluid. That \u25a0the action of such jets is at all comparable to the thrusting out of a solid body, or pole, against some resisting object, is by no means maintainable ; for the property of rigidity, which is totally and in all circumstances absent in fluids, is an indispensable condition for the production of such a result. Nor is the action due to the resistance of the external medium in any other way, but solely to the hydraulic pressure of the contained fluid on the internal surface of the walls of the hollow body. It has been supposed that the resistance of the surrounding medium acts in some degree like the walls of a cannon would in the following case : \u2014 If a bomb-shell, containing gunpowder, in the act of exploding, were placed in a cannon with the match-hole of the shell open and turned towards the breech, so that an explosive jet should be projected into the cavity of the cannon, the shell would be forced out with a much greater impetus than it would have if, cceteris paribus, it were in the open air. But this is not a parallel case, for here you have the resistance of the closed end of the cannon in one direction, and an open end, or no resistance, in the opposite direction; whereas, in the case under consideration, you have just the same resistance from the external medium in front of the body moved, as you have behind it ; and whatever tendency to motion might result from such a resistance of the medium to the jet behind, just so much would there be resisting motion in front ; so that the effect would be neutralised, and no motion would result. The truth is, that from the two absolute laws of hydraulics, \u2014 that a fluid presses equally on all portions of the surface on which it acts, and that the direction of this pressure or\nhas caused the posterior orifice to be regarded by some naturalists as the true oral orifice. The alternate action, of dilatation and contraction, have been observed to take place about fifteen times in a minute ; and have sometimes been termed the systole and the diastole. The contraction is effected rapidly, but the relaxation, or rather the dilatation of the subelastic test, takes place but slowly. These movements are synchronous throughout a chain or group of Salpce.\nAfter all, this is but an imperfect amount of locomotion, and it is extremely probable that both the single Salpce and the Salpian wreaths and chains, the latter often several} ards in length, are, like the feebly moving Pyrosoma, the sport of wind and wave, wafting them hither and thither, either to bask calmly in the sunshine, or to be broken on the rocky shore.\nAffinities of the Tunicata. \u2014 Many of the early naturalists (as we have noticed in the first part of the article) noticed the analogies existing between the Ascidia and the Ostrea, Mytilus, and other Mollusca. The compound Ascidians, however, long remained grouped with Alcyonium, until Sa-vigny, Lesueur, and Desmarest pointed out their alliances with the simple Ascidians and with Molluscs. Lesueur also demonstrated the ascidian character of Pyrosoma, and removed it from the Radiata, amongst which it had been grouped ; and Cuvier pointed out the alliance of Salpa with Ascidia and Mollusca. Soon after the publication of the important zoological conclusions thus arrived at by his distinguished countrymen, Lamarck formed these animals into a new group, under the appellation of Tuniciers* (Tunicata), provisionally placing them between the Radiata and Vaines, and expressed strong doubt of their general alliance with the Mollusca.\nJohn Hunter, who perceived the relations\nforce is at right angles to such surface,\u2014it results that the force exerted by or through a fluid contained in a closed hollow body is exactly equal in opposite directions ; that is to say, whatever may be its force impelling towards the right, by just so much does it impel towards the left ; however much it impels forwards, by just so much does it impel backwards ; and so on for up and down, and all other opposite directions : so that the one exactly antagonises the other, and an equilibrium results. But remove a portion of the wall ; in other words, make a hole through which the fluid may escape, and then the pressure, in the direction of the side in which the hole is made, is minus, or less than the force in the opposite direction, by the size of the hole. The body, therefore, moves in the direction opposite to the hole, in obedience to the plus, or excess of hydraulic pressure in that direction.\u201d The Salpa, compressing the water in its interior, produces a large amount of hydraulic force. Its posterior orifice being closed, it presents a hole or deficiency in the front only, and is impelled in the opposite direction. Also, during the act of taking in water behind, the animal moves likewise backwards, for then there is, so to speak, an inversion of the process described above. The pressure of the external water, otherwise equal on all parts of its surface, is minus behind by the size of the posterior orifice, and therefore plus in front, again impelling it backwards.\n* Applied at first to the Botryllid\u0153 only.","page":1241},{"file":"p1242.txt","language":"en","ocr_en":"1242\nTUNICATA.\nsubsisting between Ascidia and Salpa, and knew the true analogy of their exterior covering, proposed to distinguish them as a distinct group of Molluscs, under the term \u201c soft-shells,\u201d which more truly accords with their real nature than \u201cshell-less\u201d (.Ac\u00e9phales sans coquilles), as they have been subsequently designated by Cuvier*, who also, together with Blainville, regarded them as acephalous Molluscs, and sufficiently distinct to form a separate class.\nIn many of the Acephala we find two tubes for the ingress and egress water, like those of the Ascidi\u0153, and the mantle closed throughout its length, tjie walls of its cavity lined with the branchiae, and the mouth at the base of this cavity. The Ascidia being immovable, has neither adductor nor foot-muscles; for, being destitute of a locomotive organ and of valves, the muscles disappear, with the exception of some sphincter-like bands. Together with the muscles, the pedal nerve-ganglions, or rather suboesophageal or posterior ganglions are lost, and there remain only the buccal or supra-oesophageal ganglions. The differences between the heart and auricles of the Asci-dians and the other Molluscs are dependent on the modification of the branchiae ; the latter, in Ascidians, never being arranged in the four lamellae usually found in Molluscs. The digestive tube and the generative organs are essentially the same in Tunicata and Acephala, and in the latter, as in the former, the ovary and testicle are enclosed in the intestinal loops.\nYet however much resemblance we may find between the Acephala and the Tunicata, there is still more between the latter and the Bryozoa. Van Beneden observes, that if a Bryozoon was confined to its cell, and still to carry on its respiratory function by its unprotruded tentacles, and if anastomosing communications were established between the tentacles and a heart at their base, we should have the complete idea of an Ascidian. There would be two external orifices, a single mouth situated at the base of the branchial sac, vibratile cilia throughout the extent of the anastomosing tentacles, a folded intestinal canal, a supra-cesophageal ganglion, some muscular bands, and organs of generation developed around the digestive tube. There would be only wanting to complete the animal, a cloaca to receive the excrements, the sperm, and the ova, and a direct passage of communication between the respiratory and the\ncloacal cavities. The gemmiparous mode of reproduction observed in the Ctavellin\u0153, and Botryllid\u00e6 closely resembles that which obtains in the Bryozoa. With regard to the development of the Acephala, compared with\nFig.\nA, Ideal figure of an\nAscidia. (After Van\nBeneden).\na, a, the external orifices, branchial and anal ; b, straight branchial vessels; c, transverse and anastomosing branchial vessels ; d, respiratory cavity ; e, oesophagus ; f, digestive cavity ; g, rectum ; h, cloaca, communicating with branchial cavity, rectum, and generative organs ; i, integument; k, peri-intestinal cavity.\nthat of the Tunicata and Bryozoa, Van Beneden points out the following analogies : \u2014 \u201c There exist common characters between the Bryozoa and the Anodonta in this respect ; their larvae respectively swim about by means of vibratile cilia. They have a different form in the young and the adult states, and they undergo true metamorphoses. The same phenomena are seen in the Ascidians. These also have metamorphoses, perhaps, even more complete, but instead of vibratile cilia, the embryo is provided with a caudal appendage sufficiently long to serve for the purposes of locomotion ; which tail disappears, just as the vibratile cilia of the former, as soon as the animal becomes definitely fixed.\u201d\nThe embryog\u00e9nie characters appear to entirely accord with the anatomical dispositions of these groups ; and altogether we are, perhaps, justified in considering, that they approach on one side to the Acephala, and, through the Pedicellina\\, they are, on the other hand, allied to the Bryozoa, forming a closely uniting link between these two important groups. \u00a3\n790.\nB, Ideal figure of a Bryozoon.\na, entrance of the sheath ; b, tentacles, hollow throughout their length, equivalent to the straight branchial vessels ; d, the sheath ; c, mouth, leading to the digestive cavity ; g, anus ; i, integuments; k, peri-intestinal cavity.\n* Catal. Hunterian Museum, vol. i. p. 260. note.\nf For Van Beneden\u2019s researches on the development of the Pedicellina, Sec. see art. Polypifera.\nX The following tabular arrangement, given by Prof. Van Beneden in his clever exposition of the alliances of the simple Ascidians (loc. cit. p. 58.) is a valuable illustration of the subject. r Ilypocotyledones.\nAnimals - -\nEpicotyl\u00e9don\u00e9s.\nAllocotyl\u00e9don\u00e9s\nMollusques\n[.Polypes -\nf C\u00e9phalopodes. J Gast\u00e9ropodes. j Ac\u00e9phales. (.Tuniciers C Bryozoaires.\nJ Medusaires.\n'S Anthozoaires. C Alyconaires.\n{Salpiens. Pyrosomiens. Ascidiens. Polyascidiens. P\u00e9rophoriens.\nEchinodermes.","page":1242},{"file":"p1243.txt","language":"en","ocr_en":"TUN IC AT A.\t1243\nThere have been certain organic remains* figured and described as belonging to the Tunicate family, but which (with the exception of the obscure and indeterminate Ischadites K\u0153nigii) have been found to belong to the family of the Cystidea of Von Buch, closely allied to the crinoidean family of the Radiata.\nAt first sight there is considerable resemblance between many of these cystidean forms and the ascidian genus Boltenia, the body being globose or subcylindrical and pedunculated. In the Cystidea there are two more or less terminal orifices, and a third lateral aperture. The whole animal is coated with hexagonal plates variously ornamented ; the stem, perforated throughout and giving evidence of quinary arrangement. \u201c The mouth,\u201d says Von Buch, \u201cis planted in the central part of the upper surface, generally in a moveable proboscis, covered with minute plates ; the anal orifice is small, close to the mouth, perforating a plate, not surrounded by separate valvules ; and the third aperture, probably the ovariai orifice of the animal, is placed further towards the middle, but almost invariably on the upper half of the body on which the mouth is placed. It is round or oval in form, not connected with the mouth, and often covered by a five or six-sided pyramid, which seems to be composed of as many little valves.\u201d\nWe have introduced this description that we may here point out the general similarity of the external form of these obsolete radiate animals to some of the ascidian group, and that vie may in particular point out the very similar armature of ornamented hexagonal plates present in Chelyosoma, with its valve-surrounded orifices. With regard to the additional orifices, we have but to lengthen out the oviduct or efferent vessel of the Ascidia, and continue it to the surface, as in the malformation noticed and drawn by John Hunter, and a very similar arrangement of parts will apparently exist.\nThere are several points of analogy between some forms of Ascidi\u0153 and of Zoophyta asci-duida (Bowerbankia, &c.) and the Radiata: into this subject we must not now enter ; we can only allude to the observations of Messrs. Forbes and Gooclsir on the Pelonaia (see p. 1239.), and leave the subject open to further investigation.\nBibliography. \u2014 Besides the works, connected with the subject, that are referred to in the text, the following are some of the most important : \u2014 P\u00e9ron, M\u00e9moire sur le Noveau Genre Pyrosoma. Annales du Mus\u00e9um d\u2019Histoire Naturelle, t. iv. 1804. Lesueur, M\u00e9moire sur l\u2019Organisation des Pyrosomes, et sur la Place qu\u2019ils doivent occuper dans une Classification Naturelle. Lu \u00e0 la Soci\u00e9t\u00e9 Philomatique de Paris, le 4. Mars, 1815. Journal de Physique, Juin, 1815, t. lxxx. Desmarest et Lesueur, M\u00e9moire sur le Botrylle \u00e9toil\u00e9 (Botryllus stellatus). Lu \u00e0 la Soci\u00e9t\u00e9 Philomatique de Paris, le 22. Avril, 1815. Journal de Physique, Juin, 1815, t. lxxx. Desmarest et Lesueur, Extraits de deux M\u00e9moires lus \u00e0 la Soci\u00e9t\u00e9 Philomatique de Paris, en Mars et Avril, 1815, sur 1\u2019Organization de deux\n* Leucophthalmus, K\u0153nig (Sph\u0153ronites), Sa-conites, Rafinesque, &c.\nAnimaux Marins plac\u00e9s jusqu\u2019ici dans la Classe des Radiaires, et qui doivent \u00eatre rapport\u00e9s \u00e0 celles des Mollusques, &c. Bull\u00e9tin de la Soci\u00e9t\u00e9 Philomatique de Paris, livraison de Mai, 1815. Cuvier, M\u00e9moire sur les Thalides (Thalia, Brown), et sur les Biphores (Salpa, Eorskaohl). Annales du Mus\u00e9um d\u2019Histoire Naturelle, t. iv. 1804. Cuvier, M\u00e9moire sur les Ascidies et sur leur Anatomie. M\u00e9moires du Mus\u00e9um d\u2019Histoire Naturelle, t. ii. 1815. Chiaje, S. dette, Memoria sulla Storia e Notomia degli Animali senza Vertebre del Regno di Napoli, 4 vols. 4to. Napoli, 1823\u20141829. Ibid. Figure, 4to. 1822\u20141828. Savigny, J. C., M\u00e9moires sur les Animaux sans Vert\u00e8bres, pt. i. and fase. 1. de pt. ii. Recherches Anatomiques sur les Ascidies Compos\u00e9es, et sur les Ascidies Simples, 8vo. Paris, 1816. Fleming {Dr.), British Animals, 8vo. Edinburgh. Supplem. Encyclop. Brit. art. Molluscs. Quoy et Gaimard, Voyage de l\u2019Astrolabe, Zoologie, t. iii. Quoy et Gaimard, Voyage de l\u2019Oranie, t. ii. Blainville, Dictionnaire des Sciences Naturelles, art. Mollusques. Chamis^o, Dissertatio de quibusdam Animalibus e Vermium Classe Lin-n\u00e6an\u00e2. Fase. 1. De Salp\u00e2. Berolini, 1819, 4to. MacLeay, Anatomical Observations on the Natural Group of Tunicata, with the Description of three Species collected in Fox Channel during the late Northern Expedition. Read June 15. 1824. Trans. Linn. Soc. vol. xiv. 1825. Meyen, Beitr\u00e4ge zur Zoologie, gesammelt auf einer Reise um die Erde. Erste Abtheilung, \u00fcber die Salpen. Nova Acta Acad. C\u00e6s. Leop. Car. Natur. Curios, t. xvi. pars prior, 1832. Eschricht, Anatomisk-physiologiske Unders\u00f6gelser over Salperne. Royal Danish Transactions, vol. viii. 1841. Eschricht, Anatomisk Beskrivelse af Chelyosoma Mac-Leayanum. Royal Danish Transactions, vol. ix. 1842. Sars, Beskri-velser og Iagttagelser oder Nogle M\u00e6rkelige eller nye i habet bed den Bergenske Kyst lebende dyr af Polypemes, Acalephernes, Radiathernes, An-nelidernes og Molluskernes Classer, 4to. Bergen, 1835. Sars, Fauna littoralis Norwegi\u00e6, 1st part (Salp\u0153). Dalzell, A singular Mode of Propagation among the lower Animals ( Ascidia and Aplidium). Edinb. New PJiilos^JourmjvfiUjxxvi. 1839; and Isis, viii. 1839r- DaB\u00e9tl, On some\"of 'the rarer Animals on the Coast of Scotland, &c. Home (YSir E.), Lectures on Comparative Anatomy^vol? ii.\n( Salpa). 4to. London, 1814. Carus, Beitr\u00e4ge zur Kenntniss des inneren Baues und der Entwiche -lungs Geschichte der Ascidien. Nov. Act. Nat. Cur. vol. x. Carus, Beitr\u00e4ge zur Anatomie und Physiologie der Seescheiden. Meckel\u2019s Archiv, f. Physiol. B. ii. H. iv. Carus, Anatomie Compar. vol. ii. Eysenhardt, Ueber einige merkw\u00fcrdige Lebenserscheinungen an Ascidien. Nov. Act. Nat. Cur. t. xi. Lister, Phil. Trans. 1834, part ii. Milne Edwards, Observations sur les Ascidies Compos\u00e9es, qui se trouvent aux C\u00f4t\u00e9s de la Manche. M\u00e9m. Acad, des Sciences, t. xviii. Milnc Edwards, Sur la Circulation du Sang chez les Pyrosomes. Comptes Rendus de l\u2019Acad. des Sciences, t. x. 1840, p. 284. ; Sur la Circulation et sur l\u2019Existence d\u2019un Syst\u00e8mes Ner \u2022 veux chez les Salpes. Ibid. p. 408. Annales des Sc. Nat. 2de s\u00e9ries, t. xiii. Milne Edwards, Recherches Zoolog, faites pendant un Voyage en Sicile. Comptes Rendus, 1844, t. xix. p. 1137. Milne Edwards et Audouin, R\u00e9sum\u00e9 des Recherches faites aux Iles Chaussey. Ann. Sc. Nat. t. xv. Gervais, Suppl. Diet. Sc. Nat. lme vol. art. Ascidies. Coste, Recherches sur l\u2019Appareil respiratoire des Ascidiens. Comptes Rendus, 1842, t. xiv. Broderip and Sowerby, Observations on New Mollusca, &c. (Chelyosoma) Zoolog. Journal, vol. v. Johnson, Mag. Nat. Hist. 1834 {Aplidium). Penny Cyclopaedia, articles Salpacea and Tunicata. Van Beneden, Recherches sur l\u2019Embryog\u00e9nie, l\u2019Ana-toinie, et la Physiologie des Ascidies Simples. M\u00e9moires de l\u2019Acad\u00e9mie Royal de Belgique, t. xx. 1847. Forbes {E ), Forbes and Hanley\u2019s History of British Mollusca, 8vo. London, parts i. and ii. 1.848.\n{'F. Rupert Jones.)","page":1243},{"file":"p1244.txt","language":"en","ocr_en":"URETHRA.\n1244\nURETHRA.\u2014(Lat, Urethra ; Gr. o\u00fcpjj\u00f6p\u00ab; Fr. Ur\u00e8thre.')\nIn the Male.\u2014The urethra, or uro-sexual canal, is the canal by which the urine, the secretion of the testes, of the prostate and Cowper\u2019s glands, with that of the vesicul\u00e6 s\u00e9minales, are discharged. It commences at the opening in the anterior part of the neck of the bladder, and terminates at the extremity of the glans penis. In the beginning of its course it traverses the prostate gland; it then perforates the triangular ligament, which is stretched across beneath the arch of the pubis ; and after passing through this it enters the groove between and beneath the corpora cavernosa penis, and is now surrounded by the corpus spongiosum urethrae; and passing through the glands, an expansion of the latter body, it ends in a slit-like orifice, the meatus unnarius.\nDirection. \u2014 The direction of the canal varies according to the state of the penis : thus in the relaxed condition of this organ it presents curves like the italic Co procumbent ; if we trace it backwards from the meatus, it will be seen to rise towards the pubis ; thence it descends slightly, and passes beneath the arch of that bone, after which it makes a gentle curve upwards to the neck of the bladder.\nWhen the penis is erect, the urethra is straight for at least three-fourths of its course, that is, whilst it traverses the spongy body ; after which it makes a rather abrupt curve towards the opening into the bladder. In the introduction of the catheter, the surgeon, by drawing the penis forwards and upwards, straightens the anterior three-fourths of the canal, thus approximating its direction to that which it assumes in the erect state of the penis; and now, by careful manipulation, in depressing the handle of the instrument between the thighs, to a level with the urethral opening in the triangular ligament, he can, without any difficulty, succeed in passing even a straight catheter into the bladder.\nIt is important to remark that the anterior three-fourths of the urethra are loose and pendulous, whilst the remainder is fixed to the pubis in a manner presently to _ be described ; a circumstance to be borne in mind in catheterisation.\nThe urethra is divided by anatomists into three parts, each presenting characteristic peculiarities. Thus the first part is termed the prostatic portion, because it is surrounded by the prostate gland ; the second is denominated the membranous portion, because, when deprived of its surrounding structures, it is little more than a simple membrane ; it is also called the muscular part, because it is encircled by muscular fibres ; and the last, being entirely invested by the corpus spongiosum, is designated the spongy portion.\nAccording to a rough measurement, it may be stated that the spongy portion occupies about seven parts, the membranous rather less than one part, and the prostatic rather more than one part of the entire length of the tube.\nLength. \u2014 The urethra has been frequently measured to ascertain its length and diameter ; and much attention has been devoted to this subject by various observers, with the view to the treatment of strictures and other diseases incidental to this canal. It need scarcely be remarked that the urethra varies at different periods of life, according to the evolution of the generative organs ; and hence it is much shorter in the child than in the adult, and it is well known frequently to undergo a marked elongation in old persons, in consequence of hypertrophy of the prostate gland.\nI shall here introduce the measurements in length, as given us by some practical surgeons, whose attention has been especially directed to this subject, observing that the length of the urethra is expressed by the extent to which it can be stretched, by drawing the penis somewhat forcibly forward.\nAccording to Ducarp, it rarely exceeds nine inches in length. Whately examined the urethra in forty-eight subjects of different heights : these he arranged under three heads, viz. tall, middling, and short.\nIn 16 subjects of tall stature, the urethra measured\nIn 1 subject, 9 inches 6 lines.\n8\t\u201e\t9\tinches.\n2\t\u201e\t8\tinches.\n5\t\u201e\t8\tinches 6 lines.\nIn 23 of medium stature, it measured In 3 subjects, 9 inches.\n1\t\u201e\t8\tinches 9 lines.\n7\t\u201e\t8\tinches 6 lines.\n2\t\u201e\t8\tinches 3 lines.\n1\t\u201e\t7\tinches 6 lines.\nWhilst in 9 of short stature, it measured In 1 subject, 8 inches 9 lines.\n2\t\u201e\t8\tinches 6 lines.\n4\t\u201e\t8\tinches.\n2\t\u201e\t7\tinches 9 lines.\nThe collective average is therefore nearly 8\u00a3 inches, and the respective averages would stand thus: \u2014\nFor those of tall stature, it would be 8in. 91. For those of middling stature\t- 8in. 21.\nFor those of short stature -\t- 8in. 31.\nLisfranc examined the urethra in twelve adults, and he found its length to vary from 9 to 10 inches. In a negro it measured 12 inches.\nM. Petrequin has collected the various measurements of the canal, as given by the French writers on this subject, by which it appears that the estimated length varies from 5\\ inches to 12 inches. Petrequin conducted his own examinations with both straight and curved instruments. With the straight instrument he found the length of the urethra between 5f and 64 inches, whilst with a curved instrument it measured from to 7 inches. The difference he explains by the fact, that, inasmuch as the urethra is not rectilinear, a straight instrument cannot be passed through it without effacing the angle between","page":1244},{"file":"p1245.txt","language":"en","ocr_en":"1245:\nURETHRA.\nthe bulbous and membranous portions of the canal.*\nMr. Briggs observing that most of his predecessors had examined the length of the urethra after death, made a series of examinations of the canal in the living subject; and he adopted the following mode of examination :\u2014 He introduced into the bladder a catheter without a stilet, on the stem of which was marked a graduated scale of inches and fractional parts, measured from the eye of the instrument. He observes, \u201cas soon as the urine begins to flow from the catheter, which has only one eye, the line marked on the stem corresponding with the external meatus will necessarily indicate the exact length of the canal, or the distance from the meatus to its termination in the bladder. Of sixty persons in whom the urethra was measured thus, the length was found to vary from 6f to 8^ inches. In eight instances, or rather less than one-seventh of the whole (twenty of them being persons of short stature, or not exceeding 5 feet 4 inches in height), the length of the urethra was found to be under 7 inches. In forty-five instances, or three-fourths of the number, i. e. in persons of middle stature, the measurement was found to be between 7 and\n8\tinches, and in a few it exceeded 8. In some instances of very corpulent subjects, at an advanced age, the urethra was found to be 10 inches in length.\u201d He considers the average length of the passage to be 7^ or 7f inches, the external parts being in a natural condition, neither hanging in a loose, flabby state, nor unusually retracted. Briggs found the proportions of the various parts of the canal to stand relatively thus : \u2014 from the orifice to the membranous part, 6\u00a3 inches ; from thence to the bladder, 1^ inch =84 inches. As there was no stretching of the penis in the examinations thus made, it is easy to reconcile the discrepancies between Briggs\u2019s and YVhately\u2019s measurements.\nOf the relative length of the different portions of the canal, M. Petrequin cites the following authorities : \u2014 The prostatic portion measures, according to Boyer, 15 or 16 lines ; Littr\u00e9, 15 lines; Ducamp and Blandin, from 12 to 15; Senn, 13; J. Cloquet, 15. M. Petrequin agrees with Lisfranc, that the most exact measurement is from 8 to 11 lines.\nBoyer estimates the length of the membranous portion at 12 lines ; Ducamp, from\n9\tto 12; Blandin, at 10; Lisfranc, from 7 to 11. M. Petrequin has found it to vary from 6 to 9 lines, when measured by its central axis ; its upper surface measuring from 8 to 10 lines, its under surface from 4 to 5 and sometimes 6, the difference arising from the projection of the bulb beneath. The mean length of the prostatic and membranous portions taken together is, according to Malgaigne, 13 lines, but it varies from 11 to 15 lines. Petrequin\n* See the review of M. Petrequin\u2019s work ( Trait\u00e9 d\u2019Anatomie Medico-chirurgique, fyc.'), in the British and Foreign Medical Review, vol. xx. p. 136.\nhas found it to vary from 14 to 18 and sometimes 20. As to the bulbous and pendulous portions of the urethra, their rectilinear measurement is 6 inches or 6 inches and 10 lines, and the curvilinear 5 inches or 5 inches and 4 lines.*\nDiameter.\u2014 In diameter, also, the urethra varies according to age: thus in the young subject it is small ; indeed its diameter increases in proportion to the age of the individual ; and in the aged, partly in consequence of the flac-cidity of the parts surrounding it, partly from the loss of contractility in its own tissue, its capacity becomes immensely increased, so that it will readily admit a catheter of half-an-inch bore, and the escape of fragments of stone of equal size.\nEven in the infant, however, the urethra is more capacious than is generally imagined, and will admit a much larger sound than we should \u00e0 priori suppose ; a fact of no small importance in sounding at this early period of life. When the penis is erect, the urethra is diminished in diameter, from the pressure of the turgid veins of the spongy body, and from the increased distension of its own bloodvessels.\nTo ascertain the diameter of the urethra, and to compare it in persons of different ages, Sir E. Home examined the canal in two persons \u2014 one of the age of 80, and the other 30.\nAt 80. At 30.\nAt 9 lines from the meatus\nit measured -\t-\t- 5 lines 4| lines.\nAt 4 inches 3 lines from ditto 4\t4\nAt 6 inches from the meatus\n(at the bulb) -\t-\t- 7\t7A\nAt 7 inches (beginning of membranous part) -\t- 4\nAt 7 inches 9 lines (near the prostate) -\t-\t- 5\t4\nAt 8 inches (beginning of\nthe prostatic part)\t- 4\t3i\nAt 8 inches 3 lines (the\nmiddle of ditto) -\t- 6\t5\u00a3\nAt 81 inches (near the neck\nof the bladder)\t-\t- 5\t4\u00a3\nBriggs directed his attention to the diameter of the urethra in the various parts of its course, and he found the dimensions materially altered if the urethra be injected with wax or any other substance ; and the result of his examination throws considerable doubt on the conclusions of Sir Everard Home. From the casts which he made he failed to discover any sudden narrowing or constriction at the termination of the membranous part of the urethra, or any resemblance in the shape of the curve as represented in Home\u2019s plates.f\nBriggs remarks, \u201c The portion of the urethra which extends from the apex of the prostate\n* Ibid.\nt From examinations I have made myself of wax casts of the urethra, I believe the representations of Home not to be exaggerated.","page":1245},{"file":"p1246.txt","language":"en","ocr_en":"1246\tURETHRA.\nforwards to a short distance beyond the arch of the pubis, and in the natural state is the narrowest part of it, when distended, greatly exceeds the rest of the canal in its dimensions, and forms a large oblong sinus from 1 \\ to If of an inch in length ; and in its transverse diameter at its broadest part, from \u00a3gths to *-\u00a7-ths of an inch, the part of the urethra anterior to it not exceeding ^jths of an inch. The broadest part of this sinus lies directly under the arch of the symphysis pubis. The narrow part of the canal, as seen in these injections, is at the point of union between the prostatic and membranous portions.\u201d\nThe irregularities in the form of the urethra here noticed do not appear to exist at the earlier periods of life. In a cast of the urethra of a boy 11 years old, made by injecting wax, no inequalities such as those mentioned above in the adult were observable throughout its course, the diameter of the cast, which is nearly cylindrical, measuring pretty uniformly \u00a3th of an inch.\nBriggs found the curve of the urethra to commence ]\u00a3 inch anterior to the bulb ; and from this point to its termination in the bladder, to form an arc of a circle of 3\u00a3 inches in diameter, the chord of the arc being 2f inches, or rather less than one third of the circumference. In another cast the chord of the segment was found to measure 2T%-inches of a circle of 3-| inches in diameter, the inclination of the internal orifice, or entrance into the bladder, forming an obtuse angle with the general course of the urethra.\nThe same surgeon remarks, that in young subjects the posterior portion rises nearly at right angles from the rest of the canal, and consequently makes a much sharper bend ; and that this ascending portion is comparatively longer than in the adult, as was observed by Camper, who justly attributes the circumstances to the higher position of the bladder in early age. A similar remark was made by Bichat; and the fact is well known to the lithotomist, who, in directing the cutting instrument into the bladder of the child, raises the point by depressing the handle at this important stage of the operation.\nAccording to Briggs, the most depending part of the curve is at the point where the membranous portion would be intersected by a line drawn through the longitudinal axis of the symphysis pubis to the anus : this would divide the membranous part into two equal parts, and pass through the most dilated part of this portion of the canal *\nI shall now pursue the description of the canal, commencing at that part which leads immediately from the bladder, namely the prostatic portion, observing that this, together with the membranous part, is contained almost wholly within the pelvis, and the two constitute therefore the pelvic portion of the urethra, and form the true representative of the female urethra.\n* Briggs, on the Treatment of Strictures of the Urethra by Mechanical Dilatation.\nThe prostatic portion traverses the prostate gland at the distance of about two lines from the anterior, four from the posterior, and seven from the lateral surface of the gland. In this respect, however, it varies considerably: thus, in some cases, it is very close to the posterior surface, especially where the isthmus of the prostate is imperfectly developed.* The prostatic portion is from 12 to 15 lines in length, and it commences at the neck of the bladder by a round opening, which is slightly raised ; it then expands to the width of 4 or 5 lines, and gradually contracts itself into the membranous portion. It varies in length and direction in different subjects, and differs materially in these respects according to age. Lisfranc examined it in eight healthy subjects, and found the diameter of the anterior and posterior portions to vary from 3 to 4 lines, whilst the middle portion measured from 4 to 5\\ lines.\nAlthough closely invested by the dense tissue of the prostate and its capsule, this is nevertheless the most dilatable part of the whole urethra, and will readily admit the introduction of the fore-finger. The levatores prostates muscles, together with the puboprostatic ligaments, support it, and attach it to the pubis, and it is compressed by the levatores ani. The general direction of this division of the canal is obliquely downwrarcls ; it presents a slight concavity (the prostatic sinus) at its floor, where it is traversed by the caput gallinaginis, which, running from behind forwards, divides the sinus into two equal parts. In the prostatic sinus the ducts of the prostate open, assuming a crescentic arrangement around the base of the caput gallinaginis, whilst the vasa ejaculatoria terminate usually on the side of the latter body.\nThe description of the urethral orifice of the bladder belongs to the anatomy of this viscus, and to the article Bladder the reader is referred ; but it is requisite here slightly to allude to it, as it bears materially upon the general direction of this part of the urethra. When viewed from before backwards, the opening will be generally found somewhat raised, so that the floor of the urethra forms a slight depression; and this depression is materially increased in hypertrophy of the prostate, a circumstance always to be remembered in the introduction of the catheter in such cases.\nIn infancy the direction of the prostatic part is very different from what it is in after life. In consequence of the bladder at this early period being situated higher up, that is, more in the abdomen, the urethra at this part rises more vertically, and thus forms an angle with the membranous portion ; hence, as in the aged, the necessity, in passing a sound or catheter, to depress the handle to a considerable extent, and thus to raise the point of the instrument. As the prostate becomes evolved,\n* Lisfranc mentions an instance where the isthmus was wholly wanting, and the urethra formed a remarkable pouch at this part.","page":1246},{"file":"p1247.txt","language":"en","ocr_en":"URETHRA.\t1247\nthe prostatic part of the urethra gradually descends, until its general direction is more continuous with that of the membranous part. 1 shall defer the description of the caput gal-linaginis until I come to that of the general surface of the urethra.\nThe connection of the urethra to the prostate is very close, the ducts of the gland passing directly into it ; it is therefore impossible to raise it from its attachment without division of the prostatic ducts. When a catheter is introduced, the course of the canal invested by the prostate can be indistinctly traced by the finger introduced into the rectum.\nThe membranous portion (pars muscularis, isthmus urethrce) commences from the anterior part of the prostate, and extends beneath the arch of the pubis as far as the bulb : it is included between the prostatic and spongy portions, and is covered slightly at its anterior and under part by the bulb, so that it is really shorter below than above. It makes a slight curve, the concavity facing upwards. The concavity is at the distance of nearly an inch from the interpubic substance ; the convexity looks towards the perin\u00e6um. Between it and the pubis, and just beneath the pubic arch, the dorsal veins of the penis run.\nProceeding from the anterior extremity of the prostate, the membranous portion of the urethra traverses the triangular ligament, which splits into two lamellae : one passing backwards over the prostate, is continuous with the capsule of the gland, the other advances forwards over the bulb, and blends with the tendinous investment of the spongy body. The opening through which the urethra passes is round. The membranous portion forms the segment of a circle, whose radius is, according to Krause, 2i lines. This part of the canal has been termed membranous, from the idea that it represented a simple membrane when deprived of its surrounding muscular structure, and that it was wholly destitute of any investment of the spongy body. This, however, is not correct ; there is a thin layer of vascular tissue, continuous in front with the spongy body, and closely surrounding the mucous membrane of this part of the urethra, between it and its muscular layers. The vessels of this extension of the spongy body pass backwards, to terminate in the plexus surrounding the neck of the bladder : this is mixed up with elastic tissue, and constitutes a truly erectile tissue. An extension of the same structure enters into the formation of the caput gallinaginis.\nBetween the layers of the triangular ligament, and in close connection w'ith the membranous part of the urethra, are found three sets of muscular fibres (mus cuius urethralis) : they consist of the two pairs of muscles described, one by Wilson and the other by Guthrie ; and the circular fibres of Santorini, which closely surround the urethra. The anteprostate, or Cowper\u2019s glands, covered by the inferior stratum of the compressor urethrae, are placed beneath this part, and the arteries\nof the bulb are in close approximation to it, running beneath and on either side of it. The floor of the membranous portion is traversed longitudinally in the median line by the pointed end of the caput gallinaginis.\nIf a catheter be passed into the bladder, the membranous portion can be distinguished by the finger introduced into the rectum and drawn forwards, there being only a small quantity of cellular membrane interposed between the under part of its muscular investment and the intestine.\nBoyer estimated the length of the membranous portion at about 1 inch ; Ducamp from 9 to 10 lines ; Lisfranc found it in twelve subjects to vary from 7 to 11 lines. In these its anterior diameter varied from 3\u00a3 to lines, its posterior from 4j to 5 lines, and just behind the bulb it measured at least li line less than in any other part. It is universally admitted that the point of junction between the membranous and spongy portions is the narrowest part of the urethra, with the exception of the meatus.\nThe membranous part of the urethra is surrounded by muscular fibres, which have been variously described by different anatomical writers. Thus Santorini, as early as 1724, in his Observationes Anatomic\u00e6, pointed out some transverse fibres as encircling the urethra at this part: he terms them \u201c the elevator or eja-culator urethrae,\u201d and describes them as being inserted into the lower part of the urethra. Mr. Wilson, in the year 1808, gave a description of two muscles surrounding the membranous part of the urethra, the origin of which is from a tendon attached to the posterior part of the symphysis pubis, a little above its lower border: the muscle thus arising from a single origin then descends, and divides into two portions, which, reaching the membranous portion of the urethra, spread themselves out by its side, and are implanted into a common tendon below it. The muscle is termed by Wilson the compressor urethrae. In 1834, Mr. Guthrie, in his lectures at the Royal College of Surgeons, demonstrated another series of muscular fibres, as surrounding the membranous portion of the urethra, and of which he considers Wilson\u2019s muscle as a part. That portion described by Guthrie, and now known by his name, arises by a thin tendon on either side, from the ramus of the ischium, and, passing transversely, splits into two portions, one above and the other below the urethra; the two muscles are connected together above by a mesial tendon, which, passing forwards, is inserted in part into the upper part of the urethra, whilst another portion, passing backwards, is implanted into the upper surface of the front of the prostate. The under portion of the muscle is also connected with its fellow bjr a similar mesian tendon, which, advancing forwards, goes to the central tendon of the perin\u00e6um, and, sending a slip backwards, is inserted into the under part of the prostate.\nThe muscles are included between the two layers of the triangular ligament ; and the","page":1247},{"file":"p1248.txt","language":"en","ocr_en":"1248\tURETHRA.\neffect of this muscular apparatus must be to support and compress this part of the urethra, and to prevent, any retrogression of the seminal fluid in the venereal act.\nThe urethra now enters the corpus spongiosum, by which it is surrounded, until its termination at the extremity of the glans penis. The spongy body surrounds the urethra equally, except at the bulb and at the glands : in the former situation there is a much thicker layer below than above, which gives to the bulb an appearance of great dilatation, whilst at the glans there is but very little of this structure at the under part. The bulb and the glans, both dilatations of the spongy body, bear a tolerably constant relation to each other.\nThis part of the canal is called the spongy portion: it has already been stated that its length varies in different subjects, and according to the condition of the penis, being 4 or 5 inches in the flaccid state, and 6 or 8 inches in the erect condition of the organ. It commences at the termination of the membranous portion, and is lodged in a groove between and beneath the corpora cavernosa penis, forming, with its investing corpus spongiosum, a convexity, projecting beyond the general circumference of the penis.\nThe direction of the spongy portion is curved ; it passes upwards in front of the lower part of the symphysis pubis as high as the suspended part of the penis ; and then taking the direction of this organ, it bends downwards, thus forming an abrupt curve : by simple traction of the penis forwards and upwards, it can be rendered perfectly straight.\nIf the spongy part of the canal be laid open longitudinally, it is found to be p icated, the folds running from behind forwards, and dovetailing with one another when the urethra is closed. This plicated arrangement of the mucous membrane of the spongy portion was observed by Bich\u00e2t and others, and is due to the contraction of the submucous tissue : if the urethra be immersed in alcohol and examined with the aid of a simple lens, an arborescent arrangement of the folds is visible at the anterior part of the canal, in appearance not unlike the plicae in the mucous membrane of the cervix uteri.\nThe spongy portion varies in diameter in different parts ; thus, dilated at its commencement in the bulb, it gradually tapers until it reaches the glans, when it suddenly expands into the fossa navicularis, to be again contracted at the meatus.\nThe bulb (pars bulbosa urethr\u0153 et pars sub-pubica) is the widest part of the spongy portion. Lisfranc found in twelve subjects it varied in diameter from 5 to 7 lines. Home and most anatomists who have examined the urethra, have come to the general conclusion that the bulbous portion presents a decided dilatation, and a simple examination of the part would lead to a similar conclusion.\nI cannot, therefore, conceive why there should be any doubt on the subject. Injections of wax prove to my mind an undoubted dilata-\ntion of the bulbous part ; Krause and Guthrie, how\u2019ever, deny that any such exists.\nKobelt has shown, that if the bulb be injected, the corpus spongiosum at this part presents two lateral hemispherical swellings, separated from each other in the middle line by a longitudinal depression. \u201c This is caused by a septum which divides the posterior part of the bulb into two lateral symmetrical halves ; but anteriorly it is gradually lost. The two portions of which it indicates that the bulb is composed, are the analogues of the completely divided portions of the bulb and corpus spongiosum in the whole of the marsupial tribe.\u201d* \u201c In the middle of the bulb there is a slight superficial elevation (colliculus bulbi m\u00e9dius), which is situated above and between them, but does not extend so far backwards as they do, and gives passage to the membranous part of the urethra, the vessels and nerves of the bulb, and the ducts of Cowper\u2019s glands.\u201d f\nThe extremity of the caput gallinaginis sometimes reaches the bulbous portion, and the ducts of Cowper\u2019s glands terminate in its floor by two minute orifices, extremely difficult to find. This part of the canal extends for about the fourth part of an inch or less, the anterior layer of the deep perin\u00e6al fascia covers it underneath, and it is completely invested by the acceleratores urinae.\nThe remainder of the spongy portion is united to the bulbous at an angle of 45 in the flaccid state of the penis ; but when this organ is erect, this part of the canal is rendered perfectly straight : it terminates at the meatus urinarius.\nThe extremity of the spongy portion is called the glandular part (pars glandularis), being surrounded by the glans penis. When the urethra has entered the glands, it dilates into a fossa from 4 to 6 lines in length, this is termed the fossa navicularis Morgagnii. When cut transversely, it has the appearance of a longitudinal fissure. The urethra is surrounded unequally by the glans penis ; the floor of the navicular fossa is covered by a very thin layer of this extension of the spongy body, whilst its sides and upper surface have a considerable investment from the glans.\nThe urethra having traversed the corpus spongiosum and the glands, terminates at the anterior and inferior part of this body, by a small slit-like orifice of two or three lines, the long axis of which is vertical : from this a small fold of membrane passes down to join the prepuce, and is termed the fr\u0153num prce-putii. The effect of this latter is, when the penis is erect, to draw down the opening of the urethra, and thus to narrow the orifice, and direct the contents of the urethra downwards and forwards. The two sides of the meatus urinarius are kept in apposition by the projection of the glans, and they are joined below by a delicate fold of mucous\n* British and Foreign Quarterly Review, vol. xix. p. 508.\nf Ibid.","page":1248},{"file":"p1249.txt","language":"en","ocr_en":"URETHRA.\t1249\nmembrane, not unlike the fourchette of the female labia.\nThe urethral orifice is surrounded, according to Guthrie*, by a peculiar dense structure, which he considers analogous to that which forms the edge of the eyelid, and which he believes to be requisite to maintain the patency of the opening ; for if this be destroyed by ulceration, the part from which it has been removed contracts, and the opening becomes so small, as to give rise to a most troublesome form of stricture. The opening of the urethra is almost invariably the narrowest part of the canal ; and hence, if an instrument has been introduced through this, it will with facility traverse the remainder of the passage, unless there be some mechanical impediment from spasm or disease; and hence a trifling division of this part will permit the passage of a large instrument, and the escape of fragments of stone, which are frequently arrested here after the operation of lithotrity. It is but sparingly elastic. After immersion in alcohol, the mucous membrane at the meatus urinarius will be found arranged in circular folds.\nIn briefly reviewing the condition of the urethra as connected with the structures investing it, we observe that the prostatic portion, being surrounded by a body possessing considerably dilatability, remains under almost every condition passive and yielding; and hence it happens that a catheter, having reached this part of the canal, must, if its point be properly directed, enter the bladder, unless there be some enlargement of the prostate itself ; and hence the inference that no force is to be employed in passing the catheter under these circumstances.\nOn the contrary, the membranous portion of the urethra is a part of high irritability. This depends partly on the nature of the tissue itself, but mainly on the muscular apparatus connected with it. This part of the canal is most liable to irritation and spasm from general and local causes ; and is well known to be the most frequent seat of stricture. The remainder of the urethra is entirely surrounded by the corpus spongiosum, and must necessarily be influenced by the condition of that body. When the latter is distended, as in erection, the diameter of the urethra must be proportionally diminished *, and, in the undistended state of the former, it assumes its greatest degree of dilatability. Consequently, in the introduction of the catheter, the chief difficulty, even independent of organic disease, is experienced at the meatus, or at the angle formed at the junction of the bulb and anterior part of the spongy portion, or at the membranous part, the remainder of the spongy portion in the healthy state seldom offering any resistance to the progress of the instrument.\nIt will also be further remarked, that the dorsal surface of the urethra is smooth and even throughout, except in the situation of the lacuna magna, whilst its depressions and eleva-\n* Lectures on Diseases of the Bladder and Urethra.\nVOL. IV.\ntions are found upon the floor of the canal, and hence the importance in catheterisation of keeping the beak of the instrument against the superior part of the urethra.\nMucous Membrane. \u2014 The urethra is essentially a mucous canal, forming an important part of the genito-urinary mucous system. It is continuous with the mucous membrane of the bladder, and blends at the meatus with the cutaneous covering of the glans penis. There is always a distinct line of demarcation at this part, the urethral surface being moistened by a mucous secretion. When laid open, it can be frequently seen to present two distinct white lines, one at the upper, and the other at the under surface, running longitudinally ; these are supposed to indicate the original lateral division of the canal. Independent of this, the mucous membrane will be generally found arranged in longitudinal folds, with furrows between them. The folds vary in depth and breadth, the larger are found on the under surface, and they are more numerous in this situation than above. They commence at the bulb and run forwards, sometimes continuing of the same size throughout, frequently tapering and sending off, as they approach the extremity of the penis, delicate processes, which present a somewhat arborescent arrangement, not unlike that presented by the lining membrane of the uterus ; many on the dorsal aspect will be seen to terminate on either side of the lacuna magna. The folds of the urethra, which are not always visible after death, result from the contraction of the submucous layer, and are so arranged, that, when the two surfaces are in apposition, especially if the vessels of the urethra be injected, a sort of dovetailing of the mucous membrane occurs, bearing a slight resemblance to the plicated arrangement of the oesophagus of the whale.\nThe urethra after death is whitish in colour, and in some parts so transparent as to permit the veins of the corpus spongiosum to be seen through it. Its bloodvessels are readily injected, when the whole canal presents a beautiful vermilion tint. At the membranous portion, Shaw has described a considerable plexus of veins beneath the mucous membrane of the urethra: these veins are spread all over the canal, but are accumulated at the membranous part, lying one over the other in its long axis, so as to form two distinct columns with a groove between them : they unite and surround the sinus pocularis. Wilson had observed this arrangement of vessels, before Shaw published his description of them. These veins communicate with the plexus surrounding the prostate and neck of the bladder. They are best seen by inserting a tube beneath the mucous membrane, and injecting them with mercury. Shaw supposes them capable of considerable distension, and thus of producing a species of erection of this part of the tube.* In rude attempts to pass a catheter, the vessels of this part are often\n* Medico-chirurg. Trans, vol. x.\n4 L","page":1249},{"file":"p1250.txt","language":"en","ocr_en":"1250\tURETHRA.\nlacerated, and pour out a large quantity of blood. They have no communication with the veins of the corpus spongiosum itself, properly so called.\nThe colour of the mucous membrane depends on the degreee of vascularity in different parts. Thus, at the meatus, it is of a pink aspect, becoming gradually pale towards the bladder. But in the membranous portion, owing to congestion in the veins, it is very frequently much darker, as these vessels are readily distinguishable through the membrane, whilst in the prostatic part it is white. The colour of the mucous membrane is much heightened under inflammation : this is especially visible in the fossa navicularis, and at the orifice in severe attacks of gonorrhoea; and the same has been witnessed in other parts of the canal after division of the urethra, during an attack of gonorrhoea. Under inflammation it loses its smooth, polished aspect, and presents a velvety appearance.\nMr. Quekett has lately made some beautiful injections of the vessels of the mucous membrane of the urethra, in which it is seen that, in the bulbous portion, the bloodvessels running in the vallecul\u00e6 between the columns are larger and more numerous than those of the columns themselves ; whilst nearer the meatus, where the columns are either small or altogether absent, the membrane is not unfre-quently provided with villi, which resemble those of the lips and extremities of the fingers and toes in having each a single looped capillary.\nLacun\u0153. \u2014 The whole of the urethra, except the prostatic portion, is marked by minute openings, distinctly perceptible at the upper and under surface, but they are certainly larger and more numerous on the upper. They are the openings of the lacun\u0153 or mucous glands, whose office it is to secrete a bland fluid for the lubrication of the canal, and thus to facilitate the onward progress of the contents of the urethra. The lacunae vary in different individuals in size and number : some anatomists believe them to be more numerous in the membranous portion : my own observations would lead me to the conclusion, that the greater number are to be found in the spongy portion. They are termed indiscriminately the glands of Littr\u00e9 and Morgagni, or the orifices are called the lacunae of Morgagni, whilst the crypts opening into them are termed glands of Littr\u00e9. The lacunae vary in depth : in some situations they admit the passage of bristles, to the depth of two or three lines; in others they are by no means so deep, whilst in other cases they are scarcely perceptible. Their orifices face for the most part obliquely forwards towards the meatus, but now and then they pass vertically to the surface; they are found between and upon the columns of the urethra. A simple examination of the lacunae would represent them as mere inflexions of the mucous membrane of the urethra, and many of the smaller ones are of this nature : some, however, present a cellular appearance, but this seems to arise from the anastomosis of vessels distributed on them :\nthey are lined with epithelium of a character similar to that lining the urethral membrane generally, and a considerable plexus of vessels is distributed around them. Under inflammation they pour out a copious secretion, and are not unfrequently the seat of special disease. The use of the lacunae is to extend the secreting surface of the mucous membrane of the urethra, in situations where any.glandular apparatus would have been obviously inconvenient.\nIn old cases of stricture, and other diseases of the canal, they become exceedingly enlarged.\nThe lacuna magna. \u2014 Near the termination of the urethra, and within a few lines of the meatus urinarius, will be seen an inflexion of the urethral membrane, forming a cul-de-sac, into which the b unt end of a probe can be passed : this is denominated the lacuna magna, being in structure and function analogous to the other lacun\u00e6 of the urethra. The lacuna magna is a point in the anatomy of the urethra of some practical import, inasmuch as it is likely to arrest the entrance of a catheter, and to convey to the ignorant an erroneous idea of stricture. It varies in situation in different individuals. It is usually placed at about one-third of an inch from the meatus on the dorsal aspect of the fossa navicularis, so that, on separating the lips of the meatus, it can be brought into view; but it is occasionally further back, and now and then is placed on the under surface, and in many cases I have in vain tried to find it. I believe it is occasionally altogether absent. It will be found, where the columns of the urethra are developed, that they take their course towards the lacuna, and, on reaching it, pass off in slender processes to the meatus. In an urethra which I recently examined, I found a lacuna magna of considerable size in the under surface of the urethra, behind the middle of the spongy body. Into this the point of a catheter could be readily passed, and it might have been easily mistaken for stricture.\nHunter, and most of his successors, believe the matter of gonorrhoea to be incubated in the lacuna magna.\nStructure. \u2014 The urethral membrane is divisible into two distinct layers. The inner, which is analogous to other mucous surfaces, consists of a basement membrane covered throughout by epithelium. This, according to Quain and Sharpey, for the most part, is of the scaly character, but in the vicinity of the bladder it is spheroidal. Henle describes the fossa navicularis as covered with small flat and roundish scales, whilst the remaining part of the urethra is covered with a single series of prismatic particles.*\nBeneath the mucous membrane there is a layer composed of a tissue or structure of a mixed character, containing some contractile fibres, supposed to be muscular, blended with elastic tissue. It is connected to the delicate tendinous covering of the corpus spongiosum, and is supported by transverse tendinous bands distinctly visible beneath it. This layer\n* See article Mucous Membrane.","page":1250},{"file":"p1251.txt","language":"en","ocr_en":"1251\nURETHRA.\nvaries in depth in different parts, and is thicker in the membranous than in other parts of the urethra. When examined with the microscope, it presents abundant evidence of the existence of contractile fibre mixed with common elastic tissue. The relative quantity of these elements varies according to situation : thus, in the membranous portion, there is less of the contractile tissue than in the spongy portion ; a circumstance of some interest, as, this part being surrounded by a distinct muscular covering, there would be less necessity for it than in other situations where muscle is absent. The bloodvessels from the spongy body shoot through it. This contractile tissue is identical with that recently described by K\u00f6lliker as entering into the structure of the spleen and mucous canals, which have an evidently contractile power.\nThe existence of this layer has been long recognised, and the attention of anatomists was directed specially to it by Sir E. Home, who believed it to be muscular; and his opinion was supported by the observations of Mr. Wilson, who attributes the resistance occasionally, in irritable states of the urethra, offered to the introduction of the catheter, and the expulsion of bougies in like conditions, to spasm of these supposed muscular fibres. This idea, however, was opposed by Sir Charles Bell ; but the dispute is deprived of its interest since the discovery by K\u00f6lliker of the true nature of this peculiar tissue, which combines to a certain extent the attributes of organic muscular fibre and elastic tissue. This layer varies in depth in different subjects, and is generally highly developed in the robust and muscular, so as in some individuals to grasp with considerable firmness a bougie when introduced into the canal. Wilson mentions an instance of a gentleman who could \u201cas distinctly feel a contraction of the passage coming on, and taking place at one part, as he could feel any muscle act.\u201d The use of this layer must necessarily be to regulate the force of the current of fluids through the urethra.\nAccording to K\u00f6lliker the following is the arrangement of the submucous layer in various parts \u00b0of the urethra. It is termed by him the simple muscular tissue. \u201c Its relations are most complicated in the prostate gland, and the prostatic portion of the urethra, which is rich in muscular fibres. So large is the quantity of this tissue in the gland itself, that the true glandular structure constitutes scarcely one third or one fourth of the whole. On removing the mucous membrane from the prostatic portion of the urethra, the yellow longitudinal fibres of the caput gallmagims come first into view, which form the lower end of the trigone, and contain very few muscular fibres. On both sides of the caput gal-linaginis, and extending to the anterior wall of the urethra, similar yellowish longitudinal fibres present themselves, and form a strong layer towards the neck of the bladder; but towards the membranous part of the urethra they gradually decrease to a very delicate\nlayer. This longitudinal fibrous layer of the prostatic part is connected, internally to the sphincter vesic\u00e6, by a thin and indistinct layer of fibres with some of the longitudinal muscular fibres of the bladder ; but by far the greater part of it is unconnected with this latter : it consists of half fibro-cellular tissue with many nucleus-fibres, and half of evident, smooth, muscular fibres with characteristic nuclei. After this, and external to it, follow's, secondly a strong layer of yellowish circular, fibres of muscular and elastic tissue. This layer is connected above with the sphincter vesic\u00e6, where also it is most developed ; whilst below it becomes gradually thinner, and below the caput gallinaginis is either lost, or appears only in very small quantities. On removing the several muscular layers, we come at last to the proper glandular tissue of the prostate, of which individual lobes penetrate among the circular fibres just mentioned, their excretory ducts passing through the longitudinal fibres.\nIn the membranous part of the urethra the smooth muscular tissue is less developed. Under the mucous membrane, whose cellular tissue is remarkable for abundance of elastic fibres, there is a layer of longitudinal fibres, which are connected with those of the prostatic portion. These fibres consist for the most part of fibro-cellular tissue with nucleus-fibres, and include,insmallnumbers, undulating, delicate, and curved contracting fibre-cells (of the nature of smooth muscular fibres), which may be, in part, isolated ; and are from 0*07 to 0T of a line long, from U002 to 0'003 wide. They contain small nuclei from 0'012 to 0-014 long, and are more easily found in recent specimens than in those treated with acetic acid. External to these longitudinal fibres there is a strong layer of transverse fibres, which belong for the most part to the mus-culus urethralis. Some of these, however, especially those belonging to the inner layer, display some strong bundles of smooth muscular fibres, together with fibro-cellular tissue and nucleus-fibres, and a partial mixture of fasciculi of the transversely striated fibres of the musculus urethralis.\nThe smooth muscular fibres are generally still less developed in the spongy portion of the urethra. In some cases they appear in exactly the same manner as the longitudinal fibres in the membranous portion ; in other cases, longitudinal fibres may be seen, but no muscular tissue can be found mingled with the cellular tissue and nucleus-fibres of which they consist. At a certain depth, however some longitudinal fibres are distinguishable, with a more or less considerable admixture of smooth muscle, which fibres cannot be regarded as beams of the corpus cavernosum urethrae (corpus spongiosum), since they have no venous spaces between them, but rather form a continuous membrane, which limits the corpus cavernosum urethrae towards the mucous membrane. One might consider this part as belonging to the corpus cavernosum urethrae ; in which point of view\n4 l 2","page":1251},{"file":"p1252.txt","language":"en","ocr_en":"1252\tURETHRA.\nwe shall deny any muscular membrane to this region of the urethra : but it seems more natural to regard the whole corpus cavernosum as a highly developed muscular layer provided with peculiar bloodvessels ; for a large quantity of smooth muscular fibres, together with the cellular tissue, vessels, and nerves, entering into the structure of its beams and cords as far as the glans, render this body an eminently contractile structure.\u201d*\nOn laying open the urethra from its origin at the neck of the badder, the first structure we meet with is the caput gallinaginis (colliculus seminalis, caruncula seminalis, ver,u mon-tanum, crista urethr\u00e6). This is an elongated body situated on the floor of the prostatic part of the urethra : it varies in length from three quarters of an inch to an inch. Commencing by a gentle elevation of the urethra, towards which, on either side, are seen some delicate folds of membrane passing, it expands into a small oblong rounded eminence, compared to the head of a woodcock, and hence its name : it then advances gradually, tapering to a slender point, which, being continued onwards for some distance, is lost at the beginning of the membranous portion in one or two delicate longitudinal folds, and is confounded with the general surface of the urethra: the latter part is compared to the beak of the bird. The caput gallinaginis divides the prostatic sinus into two lateral depressions, into which the secretion of the prostate gland is poured.\nAt the most elevated portion of the caput gallinaginis there is a depression formed by an inflexion of mucous membrane, facing forwards, variable in size and depth, and generally capable of admitting the blunt end of an ordinary probe : in some cases it can be traced down beneath the third lobe of the prostate, to the extent of the third, or even the half, of an inch. It is called the sinus pocu-laris, utriculus prostaticus, or vesica prostatica, and is the homologue of the protometra, from which the female uterus is evolved.| On either side of this, between its laminae, or beneath it, are the terminations of the ejaculatory ducts. A general description of this small cavity has been given under the head of Prostate Gland.\nThe structure of the caput gallinaginis is this : it is for the most part formed of a raised fold of the ordinary mucous membrane of the urethra, beneath which is a longitudinal layer of elastic tissue continuous with the trigone. Some anatomists also affirm that there is mixed up in the tissue of the body a plexus of vessels, constituting a distinct erectile tissue ; and hence it has been imagined, that when its vessels are distended with blood, as during erection of the penis, it shuts up the prostatic portion of the urethra, and thus prevents the passage of the semen in a retrograde direction into the bladder. My\n* K\u00f6lliker, Beitr\u00e4ge zur Kenntniss der glatten Muskeln, in the Zeitschrift f\u00fcr Wissen.\nf See article Prostate.\nown opinion as to its use is, that, independent of this office, it is endowed with special sensibility, like the papillary orifices of the ducts of Steno and Wharton ; and that it is capable, under the influence of a stimulus, of becoming erect, and thus straightening the termination of the canals connected with it, by which the exit of the secretion of the testes and vesieul\u00e6 s\u00e9minales is favoured. I believe, further, that something more is due to these papillary orifices of the ducts of glands, and that, in consequence of their exquisite sensibility and sympathy with the glands, they possess a power, under stimulation, of eliciting the secretion and expulsion of the fluid of the bodies with which they are connected. A proof of its sensibility may be deduced from the fact, that when a bougie, introduced for the first time per urethram, reaches this point of the canal, it frequently gives rise to faintness and sickness ; and this is usually attended with an almost irresistible desire to micturate ; and further, that if this be frequently repeated, and the caput gallinaginis be irritated, a flow of semen and vesicular secretion can be excited.\nThe pathology of this portion of the canal leads to the same conclusion. For the relief of nocturnal emissions, so frequently the result of repeated self-pollution, the pr\u00e6ternatural irritability of this part may be successfully destroyed by the application of the nitrate of silver.\nIf the caput gallinaginis be gently raised by dissection from the subjacent tissue, it will be found lying on a delicate tendinous layer, with which it is intimately connected. This layer in shape resembles the body itself, being broader behind and tapering in front, and is gradually confounded with the tendinous covering of the spongy body: it is also continuous with the fascial layer of the utriculus prostaticus.\nThe caput gallinaginis results in a great measure from the coalition of the two lateral portions of the urethra, during the development of the back part of the canal, from that portion of the uro-genital sinus which gives origin to the prostate and vesieul\u00e6 s\u00e9minales, &c.\nIn the membranous portion there is nothing specially remarkable, except that delicate venous plexus, to which allusion has been already made. In the bulbous part are the terminations of the ducts of Cowper\u2019s glands ; and to these bodies I shall now direct attention.\nCowper\u2019s glands \u2014 (glandules Cowperi, gladnul\u0153 antiprostatic\u0153 vel prostatic\u0153 inferiores) are two glands situated beneath the anterior portion of the membranous part of the urethra, just behind the bulb, between the layers of the triangular ligament. A few fibres of the compressor urethr\u00e6 pass beneath them. Sometimes a single gland only is found, and occasionally there are three ; in which case, according to Cowper, the additional gland is placed just beneath the pubis. These bodies are frequently difficult to find, and in old persons they either disappear altogether, or become so soft that it is impossible to recog-","page":1252},{"file":"p1253.txt","language":"en","ocr_en":"URETHRA.\t1253\nnise them. In their natural condition they are rounded, or nearly so, and equal in size to an ordinary pea. Solid and resisting to the feel, they are of a palish red colour, and distinctly conglomerated, or composed of small lobules. The lobules of the glands are connected together by cellular membrane, and by their efferent ducts. The glands are surrounded by a strong capsule of fibrous membrane. On section they present an appearance like the pancreas, and are composed internally of elongated cellular follicles, which, according to Krause, vary from the 50th to the 25th of a line in length, and are about the 36th of a line in breadth. Some of these follicles equal in size a 16th or 25th of a line. They unite into slender ducts of about the 18th or 16th of a line in diameter; these usually coalesce into a single excretory duct. The excretory duct of each gland is occasionally double : the ducts run parallel for the distance of half an inch beneath the mucous membrane of the bulb, and approaching each other, they pierce the urethra by two exceedingly minute orifices, which are scarcely distinguishable : the best mode of demonstrating the openings of the ducts is gently to press the mucous membrane forwards with the handle of a scalpel, when a small quantity of secretion contained in them will escape, and indicate their termination on the mucous membrane.\nEach gland receives a branch from the artery of the bulb, and its veins terminate in the pudic vein.\nIt is impossible to collect any quantity of the secretion of Cowper\u2019s glands sufficient for chemical analysis. According to Krause, the fluid is somewhat similar to that secreted by the prostate ; it is of a viscid character, transparent, containing flocculi and small granulations, probably the detritus of epithelial cells, varying in size from the 900th to the 370th of a line, the greater number being about the 455th of a line.\nComparative anatomy. \u2014 As there is so little of a satisfactory nature known about the use of Cowper\u2019s glands in man, it may not be uninteresting to examine their condition in the animal kingdom generally. To elucidate this part of the subject, I select the following observations from the Le\u00e7ons d\u2019Anatomie Compar\u00e9e of Cuvier.\nAccording to Cuvier, Cowper\u2019s glands exist in all the Quadrumana and Cheiroptera, and amongst the Ferce they are found in \u00d9ie ichneumon, in the civet, hyena, cats ; in the Rodentia, except the hare ; also in the Pachydermata, most of the Ruminants, and all the Marsupiata, They are absent in the Insectivora, the bears, the racoon, otter, and marten, and in the dog. Amongst the Ruminants, they are wanting in the deer; they are absent in the Solipeds, Phoci, the amphibious Quadrirenies, and the Cetacea. It will be found that they often coexist with the prostate and vesicul\u00e6 s\u00e9minales, or with these and the vesicul\u00e6 accessorial, or with the prostate alone.\nIn the flesh-eating opossum, they are the only accessory glands, and they appear essential to this division of the Marsupiata.\nIn structure they vary considerably, but may all be arranged under one or two heads. Thus like the prostate, in some animals, there is a large reservoir in the centre of each gland, from which the excretory duct arises ; whilst in others the gland is composed of a number of minute follicles, all terminating in one common excretory duct.\nIn the squirrels and marmots they are large and vesicular, and were mistaken for vesicul\u00e6 s\u00e9minales. The fluid which they contain is semi-transparent, or of a bluish, opaline appearance, of the consistence of starch, and it is poured into the bulbous portion of the urethra by a single orifice. They are completely surrounded by a muscular or musculo-membranous envelope.\nIn the ape tribe they are proportionally much larger than in man. In the mantis they are remarkable in size. Their excretory ducts run close together prior to their termination.\nIn the bat, amongst the Cheiroptera, they are very large.\nIn the dismar of Russia they are elongated* and bent in the form of the knee.\nIn the hedgehog they are broad and round composed of a number of straight, short tubes, lying parallel, and dividing into a number of exceedingly small ramuscules. The tubes unite into a single canal, which opens into the pelvic portion of the urethra.\nIn the civet and cat they are large, and enveloped in a thick muscular layer ; but, amongst the Carnivora, they are largest in the hy\u00e6na ; the lobes and branches of their secreting tubes are exceedingly distinct and large.\nThe anti-prostate glands of the ichneumon form a remarkable swelling at the commencement of the bulb; they are rounded, and composed of v\u00e9sicules communicating together ; these unite into a single canal in each gland, which passes beneath the penis, and opens separately into a cul-de-sac, into which the urethra opens. They are surrounded by an aponeurotic and muscular la3\u2019er.\nThere is a similar structure in the marmot; they are shaped like a club, the broad end folded upwards against the handle, which contains the duct ; the mass is divided into a number of glandular cells. The excretory duct opens into a cul-de-sac,hollowed out in the bulb: this contracts into a narrow canal, which opens into the urethra, near the middle of the penis.\nIn the rat they are of large size, whitish externally, and pyriform in shape. In the agouti they are broad, rounded, and very vascular.\nIn the guinea-pig they are more rounded, but of the same structure.\nThey are spherical, and situated behind the acceleratores arising in the gerboa de Mauritanie, and pyramidal in the gerboa de Schaw. They are broad and rounded in the\n4 L 3","page":1253},{"file":"p1254.txt","language":"en","ocr_en":"1254\tURETHRA.\nelephant ; they have a similar structure as the prostate, but are comparatively larger ; they are reddish in colour, very irregular externally, and present a lobular appearance. They are divided into two portions ; a smaller, near the bulb, and another large portion. In the centre of the first there is a considerable cavity, which receives the fluid poured into it by smaller cavities, and these communicate with still smaller cellules. From the principal cavity a canal arises, which, communicating with that of the other portion of the gland, forms a single common canal. The excretory duct is formed of two branches ; it passes a short distance in the walls of the urethra, before it opens into the bulb. The glands are covered by a thick muscular layer, the fibres of which converge to a tendon, which is fixed to each corpus cavernosum.\nIn the wild boar the gland is elongated and cylindrical, formed of a firm substance composed of minute cells, which uniting form larger cells, and these communicate with a common central cavity, from which an excretory duct arises ; this opens on the side of a cul-de-sac in the commencement of the bulb of the urethra. They are each completely surrounded by a muscle. In Solipeds they form an oval swelling on each side of the pelvic portion of the urethra. They are surrounded by muscular and tendinous fibres : each opens by a dozen orifices, ranged in rows, into the adjacent part of the urethra.\nAmongst the Ruminants, in the chamois, they are of the shape and size of a pigeon\u2019s egg ; its canal terminates in the usual situation. They are similar in all ruminants where they exist.\nAmongst the Marsupialia they are remarkable for their number : thus, there are as many as six in the Mexican opossum, phalangers, phascolymus, and giant kangaroo ; four in the sarigue and kangaroo-rat. In the giant kangaroo two are placed, one by the side of the other, over the urethra, just behind the crura penis ; two others are situated on each side behind the crura, and are larger than the others. They are all invested by a muscular and aponeurotic envelope, and are composed of canals passing lengthways : they resemble in structure the prostate.\nIn the echidna and ornithorynchus, amongst the Monotremata, there is a gland on each side of the cloaca, small, and of an oval shape, containing within it a central canal opening into an excretory duct: this penetrates the constrictor cloacae, and joins a small seminal canal detached from the urethra, near its termination in the cloaca. The gland is surrounded by a thick muscle, the action of which is forcibly to throw forwards the fluid along the long excretory canal with which it is provided.\nCowper\u2019s glands are altogether wanting in birds. They are not found in reptiles generally ; but in the amphibious Urodeles the genito-urinary opening is surrounded by a glandular apparatus in some respects analogous. In fishes they are wanting.\nThey belong to the class of glands designated by Cuvier as supplementary to the male organs of generation, and their use is to pour out a fluid to lubricate the spongy portion of the urethra, and by blending with the seminal and other fluids, to assist in the general distension of the canal.\nBloodvessels of the Urethra. \u2014 The urethra is a highly vascular membrane, and its arteries are derived on either side from that branch of the pudic which enters the corpus spongiosum at the bulb, and is known by the name of the arteria corporis spongiosi urethr\u00e6 vel arteria bulbi. This artery divides into small branches, many of which are distributed on the cells of the corpus spongiosum, whilst others pass through this body, and penetrating the elastic tunic of the urethra are distributed upon its mucous surface, forming intricate plexuses between and at the basis of its columns : others are destined to the lacunae over which they form a delicate network, which conveys to these crypts a cellular appearance. They all freely anastomose on the general surface of the urethra, and at the meatus communicate with those minute branches of the arteria dorsalis penis, which, having reached the prepuce, are reflected over the cutaneous surface of the glans penis.\nThe veins either communicate with those of the spongy body, and empty themselves into the dorsal vein of the penis, or terminate at once in the prostatic plexus by means of those already described in the membranous portion.\nNerves. \u2014 The nerves are exceedingly small ; they accompany the arteries of the bulb, but cannot be traced into the urethral membrane, although the high sensibility of this structure even in health, and especially under disease, indicates at once a considerable nervous supply. The nerves are derived partly from the pudic nerves, which give minute branches, taking the course of the arteries of the bulb, and partly from the plexus situated beneath the neck of the bladder formed by some small branches of the sacral nerves and sacral ganglion of the sympathetic.\nThe lymphatics \u2014 join the superficial and deep lymphatics of the penis, and either terminate in the inguinal glands, or, passing into the pelvis with the pudic vessels, join the ganglion situated around the internal iliac artery.\nFunction. \u2014 The office of the urethra is to give exit to the urine from the bladder, and the secretions of the testes and their appendages the vesicul\u00e6 s\u00e9minales, the prostate and Cowper\u2019s glands. For the free discharge of the urine, the urethra is in a passive condition, and the penis relaxed, and as free as possible of blood ; the muscles surrounding the membranous portion together with the slightly resisting urethra yield to the efforts of the detrusor urinae, and the urine passes in a stream varying in size and force ac-","page":1254},{"file":"p1255.txt","language":"en","ocr_en":"URETHRA.\t1255\ncording to the condition of the canal. If any obstruction exists either at the prostatic part, or in any other situation, the force, size, shape, or direction, of the urinary stream is altered according to circumstances; and hence, by inspection during the passage of the urine, we can often arrive at a satisfactory conclu-\u00bb sion of the nature of the obstruction without the introduction of instruments.\nWhen, however, the seminal secretion is to be expelled, the condition of the urethra is totally altered, and the canal is diminished in diameter but increased in length from the general distension of the penis with blood, and the consequent erection of the organ. The direction of the anterior part of the urethra is altered and straightened to the utmost ; the prostatic part is raised by the action of the levator prostates, and thus forms a gentle inclination with the membranous part'; and the fluid oozing through the vasa ejaeulatoria is collected in the bulb, which thus becomes distended. Although it is not possible to see what is going on, yet we may imagine that at this period of the orgasm a sort of vermicular movement takes place, and that successive contractions and relaxations of the muscular apparatus of this part of the genito-urinary system occur. Thus I apprehend that the sphincter vesie\u00e6 effectually closes up the orifice of the bladder, whilst the levator ani and compressor prostatae expel the contents of the vesicul\u00e6 and the prostate : and further, that after the bulb is distended with fluid, the acceleratores urin\u00e6 contract with considerable and successive effort, and at this moment the muscles surrounding the membranous part contracting prevent any retrogression of the seminal and vesicular secretions, and thus the contents of the urethra are forcibly expelled through the anterior part of the canal, now made rigid by the distension of the penis, and by the contraction of its own peculiar tissue, a forcible muscular effort being required to expel the somewhat inspissated fluids. The erection of the caput gallinaginis, by the distension of its erectile tissue, has considerable influence in closing up the prostatic part of the urethra, and thus assists in preventing its retrogression into the bladder.\nThe action of the acceleratores urines in expelling the contents of the urethra in the venereal orgasm, has been denied on the high authority of Cuvier. Kobelt believes that their sole action is to compress the bulb, and thus to force the blood onwards into the glans penis, and to increase the turgescence of this body ; but that they have no direct influence either in accelerating the flow of urine as their name implies, or in the evacuation of the urethra during the act of copulation.*\nThere are few parts with which the constitution has a more close sympathy than the\n* Die M\u00e4nnlichen und Weiblichen Wollust-org\u00e4ne des Menschen, &c. Von Kobelt. Freiburg, 1844.\nurethra : this is evinced by the general disturbance of health under the influence of diseases of this canal : thus, in inflammation from gonorrhoea, or even common causes, irritative fever is set up, persisting frequently as long as the disease lasts. So also, when in suspected or actual stricture, a bougie is passed along the canal, faintness occurs, followed by a class of symptoms resembling those .of the successive stages of an ordinary intermittent. When ulceration takes place, a similar train of symptoms sets in. The same is also frequently remarked during the passage of stones, or fragments of stone, along the canal. This sympathy must be referred to the general nervous supply derived from the filaments of the sympathetic and cerebro-spinal axis. 1 he sensibility of the urethra is not the same throughout ; it is evidently more intense at the commencement, in the prostatic and membranous portions, and near the meatus, than in the spongy part generally. The pain, however, accompanying diseases of the urethra is commonly referred to the meatus, in obedience to the well-known law, that when irritation of any of the mucous surfaces produces pain, this is principally felt at the point where the mucous and cutaneous systems blend into one another, namely at the outlet of the mucous canal.\nDevelopment. \u2014 The development of the male urethra is a subject of considerable interest both in a physiological and pathological point of view, as a comprehension of the phenomena attending it enables us to offer a ready explanation of those curious malformations to which this canal is not un-frequently liable.\nFor the description of the development of the intra-pelvic portion of the urethra from the uro-genital sinus, the reader is referred to the article Prostate, in which the separation between the bladder and rectum in the male, and the bladder, rectum, and vagina of the female, is considered ; and we have, therefore, now only to trace the growth and extension of that portion of the urethra which traverses the body of the penis.\nUp to the end of the fifth or beginning of the sixth week, the external organs of generation in the male resemble those of the female, and a common opening or cloaca exists, into which the rectum, bladder, and genital organs terminate. At the anterior part of this common outlet a small projection is formed, presenting a concavity below, along which there runs a superficial groove towards the anus. This corresponds to the clitoris in the female, and the penis in the male. A slight enlargement now takes place at the extremity, which becomes the glans. In the female the two sides of the groove begin to swell out, and become the labia majora. A separation now takes place between the openings of the anus and vagina, and the perin\u00e6um begins to be formed. The opening of the uro-genital canal is a small aperture in front of the anus, at the extremity of a slit, which proceeds as far as the root of the penis or 1\t4 l 4","page":1255},{"file":"p1256.txt","language":"en","ocr_en":"1256\nURETHRA,\nclitoris, and becomes surrounded by two folds of skin which form its sides.\nIn the male, the two folds of skin which correspond to the labia majora become blended together, and form a projecting ridge, called the raph\u00e9 ; they also form the scrotum. The penis continues to increase in size, but the groove which runs along its under-surface as far as the glans, remains patent until the fourteenth or fifteenth week, when its sides swell out and adhere together, and hence the urethral canal, which is completed about the fifteenth week. The prepuce is formed at the fourth month, and at this period the orifice of the urethra appears in the form of a small slit at the extremity of the glans, but it is completely closed at first.\nAt the period of birth the pelvic portion of the urethra is more vertical than in the adult, in consequence of the position of the bladder, a great part of which is now situated in the abdomen ; the bulbous portion is situated at a greater distance from the anus than afterwards.\nThe rudiments of Cowper\u2019s glands are formed at a very early period, on each side of the genito-urinary passage.\nPathology.\u2014 Under this head are included, first, all deviations from the normal condition arising from arrest of development ; secondly, all changes in the direction and condition of the urethra depending on disease. The first are necessarily congenital, the second acquired.\nCongenital malformations. \u2014 The urethra is seldom altogether absent: it is, however, wanting in cases of decided cloacal formation, and in the female, where there is partial deficiency of the bladder (ectrophy) ; but in those cases in which the urachus remains patent, and where the urine is discharged by this canal, the urethra is always met with.\nThe urethra sometimes runs along the dorsum of the penis in the form of a broad groove. This malformation is termed epispadias, from the Greek word ime-Kau), in contradistinction to hypospadias, from 0J7ro<r7rdw, sub-traho, as in the latter malformation the penis is drawn down.\nEpispadias is frequently complicated with ectrophy of the bladder, but often exists independent of this congenital malformation.\nIn either case there is generally considerable diastasis of the symphyses pubis, the bones being united together by a long intervening ligamentous structure. In epispadias there is also a deficiency in the superior part of the prostate gland, the lobes of which are seen only below, and the veru montanum is found in its usual situation ; the prostate is generally smaller than common; the penis also is but imperfectly developed. The urethra itself forms a mere superficial channel along the dorsum penis; it is copiously supplied with large lacunae, the corpus spongiosum is wanting above, and the glans is cleft; the prepuce ceases at the corona glandis.\nIn a case which I recently examined, the bladder was small, and, as if to supply the\ndeficiency in the muscular apparatus of the membranous part of the urethra, which was necessarily wanting, the acceleratores urinae were immensely developed ; their superior attachment was of course deficient.\nHypospadias implies that form of malformation in which the urethra runs in a groove beneath the penis ; it is subject to considerable variation. The most common variety is that where the urethra forms a simple groove, and the penis is bent downwards, the prepuce being wanting. If this groove be continued down deeply to the perinaeum, between the two sides of a fissured scrotum, the whole genital system takes on more or less of the female character, and hence has arisen the false notion of the subject of hermaphroditism.\nThere are many modifications of this malformation. Otto* mentions one case where the penis was cleft, and the vestige of the divided urethra was easily recognised, a fossa navicularis being distinguishable on either side, as well as the termination of an ejaculatory duct. The prostate was wanting. Sometimes the urethra is perfect in the glans, and throughout the remainder of its course it is open beneath the penis.\nThe urethra sometimes terminates before it reaches its usual destination. Thus it opens into the rectum, or into the perinaeum; in other cases it goes no further than the root of the scrotum ; sometimes it ends at the corona glandis, or it may end at any distance between this body and the bulb. Occasionally the opening is altogether wanting (atresia urethr\u0153), or it is covered by a delicate fold of skin. When it terminates in any of these unusual situations, the opening is very small, sometimes so small as not to admit the introduction of a bristle. Now and then we meet with a rudimentary meatus in the usual situation, terminating in a cul-de-sac, and beneath this a small urethral orifice. When the urethra ends at the corona glandis, the prepuce is imperfect ; it is thrown into a fold resembling the hood of a monk, and is hence denominated the monk\u2019s hood prepuce, and the glans is uncovered.\nDeviations in diamater, although occasionally congenital, are generally the result of disease. A preternaturally contracted state of the urethra is sometimes found at birth. This may happen at the orifice as before mentioned, or in other parts of the canal. Under this condition, the bladder, ureters, and pelves of the kidneys are sometimes dilated, as in ordinary cases of stricture, f Congenital stricture of the urethra is nevertheless exceedingly rare.\nDiseases and accidents. \u2014 Dilated urethra is not uncommon as the consequence of stricture. When the bladder is unable to get rid of its contents, the inordinate efforts to overcome the resistance occasion sometimes a gradual dilatation of the urethra behind the seat of stricture. This condition is at-\n* Monstrorum Sexcentorum Descriptio Ana* tomica.\nf See article Teeatology.","page":1256},{"file":"p1257.txt","language":"en","ocr_en":"URETHRA.\n1257\ntended with excessive irritation along the whole course of the canal, and the prostate gland becomes hypertrophied in consequence. Sir Benjamin Brodie mentions a remarkable case of this description. In this case the urethra, behind the obstruction, was so dilated, that, whenever the patient attempted to pass his urine, a fluctuating tumour, as large as a small orange, was felt in the perin\u00e6um. It was punctured, and immediately the urine gushed out in a full stream.\nThe escape of calculi from the bladder often occasions dilatation of the urethra into pouches ; and such dilatations occur independent of ulceration.\nOn dissection of these pouches, the mucous membrane is usually found injected and thickened, presenting fungous yegetations, and occasionally coated with lymph.\nThe urethra deviates frequently from its normal direction : thus, in large scrotal herni\u00e6, and hydroceles of large size, it takes a serpentine course : so also, when tumours press on the canal, its course is altered. The same happens in enlargement of the prostate gland, and from the projection of its middle lobe, the urethra divides itself into two streams. Abscesses also distort the canal from its natural direction. Tumours in the pelvis, as a collection of hydatids between the bladder and rectum, in consequence of the influence they exert on the bladder, frequently distort the urethra from its normal direction. This distortion occurs more especially to the pelvic part of the canal. Under these circumstances the urethra is generally lengthened to a greater or less extent.\nSolutions of continuity result either from mechanical injury, or from disease. The urethra may be wholly or in part divided. Most commonly, if the division be incomplete, a small fistulous opening remains for a short time, which subsequently, if let alone, completely closes. Incisions through the membranous part of the urethra, as in the operation of lithotomy, speedily cicatrise.\nThe most serious injuries to the urethra are those resulting from blows or falls on the perin\u00e6um, especially when they are accompanied by fracture of the ossa pubis. In these cases there is either partial or complete solution of continuity. The membranous part of the urethra, from its position beneath the pubic arch, most frequently suffers. The nature of the injury may be generally recognised by the escape of blood with the urine, or by complete retention of urine. An elastic catheter, carefully introduced, will in the former case generally grate against the torn part In complete division of the urethra, if the patient survive the injury, the torn ends are, in the progress of the cicatrisation and contraction, brought into apposition, and the continuity of the tube is restored : stricture is the almost necessary consequence. If, however, the cure is not accomplished, urinary fistula is the unfortunate result. When the complete division of the urethra, is accompanied with fracture of the pubis, the two\nends of the canal are frequently so completely separated, that extensive extravasation of urine ensues, and the case is generally fatal.\nSevere contusion of the urethra, independent of rupture, sometimes leads to ulceration or sloughing, and occasionally gives rise to stricture by inducing chronic inflammation of the injured part.\nLaceration of the urethra occasionally happens from the introduction of foreign bodies, or from the escape of fragments of calculi, especially after the operation of lithotrity. The torn part generally heals under simple treatment, or the urine is infiltrated into the spongy body, and abscess is the consequence. Laceration often attends violent efforts to force a stricture with the sound or catheter : these injuries usually happen at the under part of the canal, and frequently heal if all violence be desisted from. In a case of lacerated urethra brought into the London Llospital, a large pouch as big as a small orange was formed in the scrotum, into which, when the man attempted to micturate, the urine was forced ; he then squeezed it through the natural passage. By degrees this pouch gradually contracted, and no vestige of it remained.\nIn\u00dfammation of the urethra, whether common or specific, is usually of the catarrhal form : common inflammation is comparatively rare ; but it may be excited by chemical and mechanical stimuli, or it may depend entirely on constitutional indisposition : thus strong injections hare been known to induce every symptom of severe urethritis simulating an attack of gonorrhoea; but the disease is speedily arrested by ordinary antiphlogistic treatment. Under the head of mechanical causes may be enumerated the introduction of the catheter or bougie, and other foreign bodies, and the passage of calculi entire or in fragments, and blows on the perin\u00e6um.\nThe urethra is sometimes 'inflamed from constitutional causes, or sympathetically : thus stone or calculus in the bladder and kidneys frequently leads to urethritis ; some substances taken into the stomach produce the disease, as asparagus, cantharides, and turpentine, and arsenic if administered in large doses, especially if the poison be allowed to accumulate in the system.\nIn persons of a gouty diathesis, urethritis occasionally occurs, followed by a discharge of muco-pus. According to Prout, \u201c gouty irritation of the urethra often assumes all the characters of gonorrhoea, and is not only attended by a profuse discharge, but with great irritation and scalding in passing water.\u201d During the prevalence of influenza, I have witnessed a severe attack of urethral inflammation accompanied with copious puriform secretion, and attended with the ordinary symptoms of clap ; under the influence of a purge it passed off entirely in a few days. Suppression of cutaneous eruptions, according to the German pathologists, not unfrequently causes urethritis. Inordinate indulgence in venery, and masturbation, produce inflam ma-","page":1257},{"file":"p1258.txt","language":"en","ocr_en":"1258\tURETHRA.\ntion of the urethra by the constant irritation of the part. So also the irritation of the menstrual and leucorrhoeal discharges, when applied to the male urethra under states of high excitation, induces a similar pathological condition.\nGroupai exudations are sometimes found in the urethra. These assume either a tubular form, or the lymph is effused in the form of long shreds.* The mucous follicles situated in the vicinity of the meatus are, according to Kleeberg, of K\u00f6nigsberg, liable to a form of inflammation similar to that which attacks the follicles of the genital organs of the female. He thinks that it is sometimes connected with clap, or gleet, and often independent of either. It is indicated by a swollen state of the circumference of the mouth of the urethra, which is of a brownish red colour. There is slight pain in making water. The orifices of the lacunae become closed by inflammation, and, in the course of two or three days, pustules are formed in their places, which break and discharge a yellow pus. \u201c The orifices of the large mucous follicles are now seen dilated and surrounded by a swollen dark-red border, and they discharge a muco-purulent fluid into the urethra : if this be washed off, and the glands compressed, the fluid is distinctly seen issuing from these openings.\u201d j- The disease sometimes assumes a chronic form. J\nThe specific causes of inflammation of the urethra are syphilis, gonorrhoea, and small pox. Of these, gonorrhoea is the most frequent. Syphilitic inflammation, producing chancre, is by no means unfrequent, as Ricord has proved. The disease makes its appearance on the 6th, 8th, and 12th days after connection. Inoculation from the discharge produces the true syphilitic pustule. It often attacks the meatus urinarius.\nInflammation from gonorrhoea may be either acute or subacute, or the disease may be virulent or simple, the difference being in degree rather than in kind. The disease begins in the anterior part of the canal, and is supposed to attack first the lacuna magna. Hunter limited its specific extent to an inch and a half from the meatus. The period of incubation of the poison varies from one to ten days, and is sometimes prolonged even beyond this, if we can believe the accounts of patients. Hunter has known it to appear a few hours after connection, and Sir Astley Cooper met with a case in which it did not make its appearance until after fourteen weeks from the time of inoculation.\nThe pathological changes in the urethra from this disease may be briefly described. The disease, commencing at the part indicated, if left to take its own course, gradually extends itself in a retrograde direction as far as the neck of the bladder, and, in very severe cases, the\n* See Pathological Museum of the College of Surgeons, Preparation No. 2576.\nf Zeitschrift f\u00fcr die gesammte Mediein, Band ii. Heft 2.\n$ British and Foreign Med. Review, vol. iii.\nmucous membrane of this viscus becomes involved. The urethral membrane is swollen, red, and exceedingly vascular : this can only be generally observed at the orifice, but it has also been seen in the middle of the canal in cases where, during an attack of gonorrhoea, the urethra has been divided. The intensity of the inflammation is not uniform. Thus, the lacuna magna, and the beginning of the spongy portion, are most severely attacked. The inflammation attacks the lacunae, giving rise to pain and swelling in various parts of the canal ; even the spongy body itself becomes, by contiguity, implicated in the disease, and interstitial deposition of fibrin takes place in its cells, causing unequal distension of this body during erection, and hence painful chordee. Abscess in this body is not very unfrequent. By continuity of surface, the disease attacks the mucous lining of Cowper\u2019s glands and the ducts of the prostate, whilst through the ejaculatory vessels it passes to the vesicul\u00e6 s\u00e9minales, and by the vasa deferentia to the epididymis, causing hernia humoralis. When the latter structures become affected, the inflammation of the urethra itself in a great measure subsides, and the discharge ceases, usually to reappear in a mitigated form.\nThe inflammation of gonorrhoea is necessarily of the catarrhal character. At the first onset of the affection there is a slight weeping from the meatus of a transparent fluid, in which mucus particles are floating, probably only the natural secretion of the urethra in excess. This soon gives place to a semi-puriform secretion, which glues the edges of the orifice together. It afterwards becomes more distinctly puriform, and at the height of the inflammation, the discharge, which has increased in quantity, puts on a greenish hue, and is of a faint, sickly odour, as the disease subsides. It changes again as to its character in exactly the inverse order of its appearance. It frequently leaves behind it a gleety discharge. The seat of this discharge in gleet is either the general mucous surface of the urethra, the lacunae, or the anti-prostatic ducts, and in many instances the ducts of the prostate gland are alone affected in long persistent gleets.\nWhen gonorrhoea coexists with chancre, the discharge has usually a greyish or reddish tint, or sanious aspect.\nAmong the most important consequences of this affection, we may mention simple erosion and cicatrices from ulceration producing stricture, and, which is much more common, chronic thickening of the urethra giving rise to stricture. If the diseased urethra be examined after death, according to Hunter, the fossa navicularis and its lacunae are found more vascular than usual, and the lacunae filled with matter. In more severe cases the membranous part, Cowper\u2019s glands, and their ducts, are involved in the disease. Littr\u00e9 found, after examining forty cases, Cowper\u2019s glands morbid in one only ; and Morgagni met with only one or two instances of a","page":1258},{"file":"p1259.txt","language":"en","ocr_en":"URETHRA.\t1259\nsimilar kind. The prostatic part of the urethra evinces signs of disease in severe attacks of clap.\nThe glands of Cowper are sometimes inflamed, independent of gonorrhoea, and become indurated ; or they occasionally suppurate.\nUlceration of the urethra may arise from common and specific causes. In the latter category, chancres take the first rank ; these can only occur in the anterior part of the canal, and are generally found at the urethral orifice.\nUlceration, independent of specific cause, is sufficiently common : thus, it may arise spontaneously, or as the consequence of stricture, or foreign bodies in the canal, as calculi, pieces of bone, bougies, &c. Spontaneous ulceration of the urethra is exceedingly rare ; it is not mentioned, usually, by writers on the diseases of the urethra. 1 have met with one instance of it myself : in this case three successive attacks of ulceration had occurred, which terminated in urinary fistul\u00e6, one anterior to the scrotum, one in the perin\u00e6um, and one in the vicinity of the tuber ischii. They were each preceded by rigors, and other signs of fever, and were accompanied by much constitutional disturbance ; no stricture, or other appreciable disease of the urethra whatever, had preceded the ulcerative process.\nUlceration behind a stricture is very common ; it depends on inflammation attacking the part as the result of long continued irritation.\nA stricture itself sometimes becomes the seat of ulceration, when bougies and catheters are used with violence for its cure. It also happens, though rarely, that spontaneous ulceration of the stricture occurs, by which the stricture is cured. Sir Benjamin Brodie relates an instance of this.\nUlceration consequent on tubercular deposit now and then occurs in the urethra, but only in cases where tuberculosis prevails over the entire urinary apparatus.* An instance of this description occurred to Mr. Robinson of Peckham, in a man who had been the subject of extensive tuberculosis in the urinary and genital organs. The disease appears to attack the follicles.\nCancerous ulceration attacks the male urethra in carcinoma of the glans penis and other parts of the organ.\nSloughing of the urethra, as a consequence of stricture and violent catheterisation, often leads to the destruction of a considerable portion of the canal.\nIn severe cases of small pox, pustules are not unfrequently found in the urethral membrane.\nAbscesses. \u2014 As a consequence of inflammation, abscesses form in connection with the urethra : they may be acute or chronic : sometimes they communicate with the urethra, but frequently they have no such communication. Abscesses may take place in any part adjacent to the canal: thus, in severe\ngonorrhoeas, suppuration in the spongy body from inflammation of contiguous parts is not very uncommon ; the same also is occasionally met with in the perin\u00e6um, in Cowper\u2019s glands, and even in the prostate. Abscesses are not unfrequently met with as the consequence of injury to the urethra from blows or falls upon the part. In all such cases the abscess communicates with the canal, and frequently, if not generally, is attended with extravasation of urine.\nThe most common forms are those depending on stricture ; they are preceded by ulceration or sloughing, which generally takes place behind the seat of stricture. Syme thinks that ulceration of the urethra is secondary to the formation of matter, which is external to the urethra, and precedes the ulceration. Abscesses now and then form in the vicinity of the urethra without any direct, or indirect communication with the canal ; this happens occasionally in cachectic states of the constitution, in which abscesses are not unfrequent in the vicinity of other mucous outlets, as the rectum. When these are opened, the matter is disgustingly foetid, and is strongly impregnated with an urinary odour, although no urine has become mixed with it, no breach having occurred in the urethral membrane.\nOne of the most common forms of abscesses connected with the urethra arises from inflammation of the lacun\u00e6 during a severe attack of gonorrhoea. Under these circumstances the orifice of the lacuna, the subject of the disease, probably becomes closed by adhesive inflammation, a small, round, indolent tumour is formed in the direction of the spongy body, or in the perin\u00e6um. Ulceration or bursting into the urethral canal often occurs, and the urine escapes into the sac, causing increase of inflammation ; and now distinct suppuration having taken place, fluctuation becomes evident, and either the matter escapes externally by ulceration, or the surgeon is induced to puncture it with a lancet.\nTubercles. \u2014 Louis states that he has rarely examined the urethra of tuberculous subjects. Rayer, however, quotes two cases, one of which he witnessed himself, and the other was communicated to him by Vernois. The former occurred in a man thirty-six years of age, who had tubercles in his kidneys, testicles, and prostate ; the latter in a boy, aged twelve, with tubercles in the kidneys and on the surface of the peritoneum ; in this case the whole urethra was apparently affected ; in the other, only two inches and four lines of the vesical end were diseased.\nRicord presented to the Academy of Medicine* a curious specimen of an urethra completely studded with miliary tubercles. It was removed from a man who had undergone the operation of castration for tubercular deposit in the testicle some years previously. The prostate contained a tubercular excavation.\nSee Rokitansky.\nSeance du 2 Avril.","page":1259},{"file":"p1260.txt","language":"en","ocr_en":"URETHRA.\n1260\nThe urethra is sometimes traversed by cords, in some respects resembling at first sight the cord\u0153 Villisii of the longitudinal sinus, I presume they are formed by organisation of effused lymph. There is a curious specimen of this disease in the Museum of St. Bartholomew\u2019s Hospital, marked in the Catalogue 30. 37. The patient from whom the preparation was taken had been frequently the subject of catheterization. The disease is exceedingly rare.\nStricture. \u2014 Under this head are enumerated all contractions of the urethra depending on alteration of the tissue of the canal itself, or the parts immediately surrounding it. Strictures are commonly arranged under three heads \u2014 spasmodic, permanent or organic, and inflammatory or irritable stricture.\nA spasmodic stricture may be defined to be a temporary diminution in the diameter of the urethra, sometimes to such an extent as to effect its complete closure, from spasm of the muscles surrounding it. The term can only, with strict propriety, be applied to a temporary contraction of the muscles investing the membranous portion, as no action of the acceleratores urin\u00e6 is equal to the complete closure of the spongy part. The common seat of spasmodic stricture is therefore the membranous part.\nSpasm of the urethra arises from various causes, as exposure to cold, indulgence in wine and venery, and gonorrhoeal inflammation. So also, certain medicines, as cantharides, when taken into the stomach, or applied endermically, may induce a similar condition.\nAlthough genuine spasm is confined to the membranous part, yet the remainder of the urethra is liable to temporary contraction from general irritation of the mucous surface, as where the urine is loaded with lithates, and hence becomes exceedingly irritating. Under these circumstances the stream of urine is diminished, and the urethra resists the introduction of the catheter. This condition probably depends on irritability of those fibres, be they muscular or not, which enter so largely into the structure of the outer layer of the urethra.\nSpasmodic stricture may be recognised in the following manner : a patient observes a sensible diminution in the stream of water, aggravated by drinking and free living. After unusual indulgence in wine or venery, he finds suddenly that he is unable to pass a drop of water ; the surgeon, on attempting to introduce an elastic catheter, which is the best adapted for the case, finds the progress of the instrument impeded at the membranous part of the urethra ; by gentle pressure, however, the spasm yields, and the instrument enters the bladder suddenly, and all sense of contraction disappears. On using the instrument on the following day, he finds that it passes with perfect freedom..\nBy permanent stricture is understood a narrowing of the canal from organic change in the tissue of the urethra itself, or the corpus\nspongiosum. Permanent stricture may attack any portion of the urethra ; even the prostalic part, the fossa navicularis, and the bulb have been the seat of stricture : thus, Ricord and Cross have met with stricture in the prostatic portions, and the fossa navicularis has been found to be the seat of the disease (after ulceration) ; but, although it is by no means unfrequent in the spongy portion, it is most common in the anterior part of the membranous part of the canal. This subject has been examined by various writers on urethral diseases, but the most extended researches are those of Mr. Phillips, and I therefore append the result of his observations. He selected a number of cases for examination, and he found that In 9 cases the stricture was distant from the\n\tmeatus -\t-\t-\t1 inch.\n8\t99\t99\tfrom 1 to 2 inches.\n13\t99\t99\t2 to 3\n11\t99\t99\t3 to 4\n98\t99\t99\t4 to 5\u00a3\n40\t99\t99\t5* to 6*\n10\t99\t99\t61- to\nThis corresponds with the observations of Ducamp, who found that, in five cases out of six, strictures are found at the distance of about 5 inches from the meatus, or from 4 inches 9 lines to 5 inches 3 lines. Amussat states that the most common seat of the disease is the point of junction between the bulb and membranous portions.\nVarieties of permanent stricture.\u2014 Strictures may be spontaneous or traumatic. Traumatic strictures generally occur at the membranous portion, but they are occasionally found in the spongy part. The former result from contusions or lacerations, the latter from division of the canal by cutting instruments, as after the extraction of impacted calculi, or after complete division. Whatever be the cause of traumatic stricture, if stricture ensues after a wound of the urethra, a cicatrix occurs, as in other situations, and a tendinous puckering of the membrane takes place, giving rise to the most intractable form of the disease. If, however, the stricture results from simple contusion inflammation attacks the part and the stricture is produced as in the common class. After ulceration of the urethra from chancre a puckering of the membrane gives rise to stricture in its character resembling the ordinary traumatic variety.\nThe most simple form of permanent stricture is where the urethra is traversed by a fold of membrane thrown across in the form of a bridle. In this case the stricture is usually in the floor of the canal. It may occur in any part, except the prostatic, but its usual seat is the commencement of the spongy portion. The diameter of the urethra is thus only partially occluded, the shape of the stricture being somewhat crescentic. When the urethra is completely encircled, it appears as if a slender thread w ere tied around it, and thus an annidar stricture, or bridle, is formed, the opening being usually in the middle. The efforts to micturate often push forward the","page":1260},{"file":"p1261.txt","language":"en","ocr_en":"URETHRA.\nstrictured part, thus inducing a valvular appearance. Authorities vary as to the formation of this stricture. Some, as Ducamp and Laennec, believe it to depend on the organisation of false membrane thrown out on the mucous surface. Amussat attributes it to the healing of an ulcer, but there can be little doubt that both causes may give rise to a similar condition. Arutzenius considers it due to a swelling of the mucous membrane, and consequent loosening from -the subjacent tissue : thus the membrane becomes wrinkled, and a fold is formed on its surface.\nHunter attributes the origin of these strictures to spasm of the circular muscular fibres of the urethra. Sir C. Bell describes them as occasionally splitting into branches, and running in a longitudinal rather than a circular direction. He considers them as the result of inflammation of the mucous surface : to this opinion most modern surgeons subscribe. Sometimes two or more annular or bridle strictures coexist\u00e2t short intervals in the same urethra. Hunter met with six, Lallemand seven, and Calot as many as eight.\nThe next variety of permanent or organic stricture is that in which the urethra is narrowed to a much greater extent of its course than in the former case. In these cases half an inch or an inch, or even the whole extent of the spongy part of the urethra, is more or less contracted. The stricture occupies one or other side, or it completely encircles the tube. It varies in consistence, from a soft, yielding thickening of the membrane, to a complete cartilaginous hardening. The disease in its most simple form occupies either the mucous layer alone, or the submucous elastic layer ; but it is not limited to this, for in many cases the tissue intervening between the submucous layer and the spongy body is the seat of disease, whilst in others even the spongy body itself, whose cells are obliterated by the deposition of lymph, becomes thickened and indurated, and thus encroaches on the urethral tube. I regard genuine simple stricture as dependent on hypertrophy of the mucous or epithelial layer and the submucous elastic lamina of the urethra.\nStricture in its progress passes through various stages, from simple thickening to complete cartilaginous induration. The complete cartilaginous conversion of stricture is more frequently found where the stricture is situated in the spongy portion,\nThe most intractable stricture is that which results from ulceration of the meatus ; it is frequently associated with adhesion of the prepuce to the glands ; sometimes the strictured part will not permit the passage of a bristle. For the cure of this disease incision is necessary.\nAmong the most common attendants on stricture of the urethra are hernial protrusions of the mucous membrane of the bladder, between the columns of the detrusor urin\u0153, in the form of sacculi. As a consequence of stricture of the urethra, may be mentioned rupture of the canal and of the bladder itself.\nIt is probable that these are preceded by interstitial absorption, and not unlikely by sloughing or ulceration. And the straining to overcome the impediment to the exit of the urine leads frequently to the formation of hernia at the groin, and has been attended with rupture of the rectus abdominis muscle.*\nIn old strictures the membrane of the urethra is usually hypertrophied, the orifices of the lacunae are enlarged, and the prostatic ducts considerably dilated. The prostate gland itself is frequently hypertrophied in consequence of the general irritation of the urethra.\nFalse passages. \u2014 A false passage may be formed in any part of the canal, according to the seat of stricture ; there may be one only, or several may co-exist. The under part of the urethra usually gives way, owing to the direction given to the point of the catheter. Sometimes the catheter, passing beneath the stricture, re-enters the urethra, and is then directed into the bladder, or it may be forced onwards through the prostate gland ; occasionally the catheter penetrates but a short distance, and on withdrawal enters the natural passage. False passages through the third lobe of the prostate gland not unrre-quently result from unskilful attempts to relieve retention of urine from enlarged prostate ; in this way the gland may be perforated in three or four places.\nWhen false passages are maintained by the frequent attempts to pass the catheter, they become lined by a mucous membrane, and the urine is in some ever afterwards discharged through the newly formed canals.\nFistul\u00e6 in perin\u0153o (urinary fistul\u00e6) \u2014are a common consequence of ulceration behind a stricture ; they are generally preceded by abscess, and sometimes by gangrene. Not unfrequently they arise independently of any obstruction, as after abscess from acute gonorrhoeal inflammation. Urinary fistul\u00e6 result also from wounds of the canal, as after the operation of lithotomy, or the extraction of calculi from the urethra. Suppuration of the lacunae sometimes leads to urinary fistula; this happens occasionally to the lacuna magna!\n. urinary fistula there is sometimes a single opening into the urethra, with many external openings. These are found in various situations : thus they occasionally exist anterior to the scrotum, sometimes in the perin\u00e6um, and now and then they open into the rectum! or even as low down as the tuberosities of the ischia : the external and internal openings do not always correspond, the intervening tract taking a tortuous course. The walls of the fistula are much thickened and indurated, and this induration extends for some distance to the parts around, and involves a large extent of the cellular tissue and skin, so that the perin\u00e6um feels as hard as cartilage : the canal of the fistula is lined by a mucous membrane.\nSometimes the fistula passes upwards to-\n* See Dublin Journal of Medical Science, Mav 1842, p. 308.\t*","page":1261},{"file":"p1262.txt","language":"en","ocr_en":"URETHRA.\n1262\nwards the pubis, and gives rise to inflammation and caries of the bone ; nay, it may take its course even to the groin and lower part of the abdomen.\nFor obv\u2019ous reasons, stricture seldom happens prior to puberty; nevertheless some rare instances are recorded of the disease in young children. I do not here allude to such as result from mechanical injury, for these may happen at any age. Hunter mentions a case of stricture accompanied with fistula in perin\u00e6o in a boy four years old, but he does not speak of the cause.* He also mentions one in a boy eleven years old. In the Museum of the College of Surgeons there is a preparation (No. 2535.) of the bladder and penis of a boy seven years of age, laid open to show a stricture at the membranous part of the urethra, and behind the stricture a small stone is lodged. The case occurred to Sir E. Home, who also mentions a case of stricture occurring at ten years of age.\nWhat is the true nature of a stricture ? I believe that a stricture (I speak of the permanent class) may result from the organisation of lymph effused upon the surface of the mucous membrane, as in the formation of bridle strictures. Secondly, that it may arise from the healing or cicatrisation of an ulcer, in which case a fibrous puckering is produced. Thirdly, that it may arise from hypertrophy of the elastic layer beneath the mucous membrane. Fourthly, from deposition of lymph between the urethra and spongy body ; and, lastly, from deposit and organisation of lymph in the cells of the spongy body ; and that these conditions may all co-exist.\nWhen the strictured part is laid open, it will be found that at the exact seat of stricture the mucous surface is raised; and beneath this the submucous elastic lamina is observed distinctly thickened, of a firm texture, and deprived more or less of its natural elasticity, this thickening passing off gradually and insensibly in a longitudinal direction until it altogether disappears and the canal resumes its natural diameter, or is dilated or contracted according to circumstances. The thickening usually extends equally around the urethra, so that the opening of the canal is in the middle of the stricture, but in some instances it is confined to one side. On attempting to dissect the urethra from the subjacent spongy body, it will be found that its adhesion at the seat of stricture is so complete, that it cannot be raised without much difficulty, and in many cases the separation of the two structures cannot be accomplished at all. The spongy body itself is frequently thickened, and the delicate tissue forming the septa of its cells is much hypertrophied.\nCauses of stricture. \u2014 Most strictures are the result of inflammation of the urethra. Long persistent and neglected claps constitute by far the most common of the causes of the disease.\nI have no hesitation in admitting that the indiscriminate use of stimulating injections\n* Hunter, On the Venereal Disease, p. 115.\nmay be fairly set down as the occasional cause of stricture. Masturbation, and the too frequent indulgence in the venereal act, may be enumerated amongst the occasional causes of the disease.\nCo-existence of stone with stricture. \u2014 It often happens that calculus in the bladder co-exists with stricture in the urethra, and the connection between the two diseases appears easily accounted for. But some curious circumstances occasionally occurring in these cases, render it very doubtful whether we are justified in indiscriminately attributing the formation of ston\u00e9 to the impediment to the discharge of water from the stricture ; nay, the circumstances to which I allude rather tend to prove the converse of the proposition, namely, that the stricture depends on the irritation in the urethra, maintained by the presence of stone in the bladder. The inference appears legitimately deducible from the fact, that cases of severe stricture have been entirely cured by the removal of the stone from the bladder by lithotomy.*\nDiseased lacunce.\u2014 Sometimes one of the lacunae becomes the seat of chronic inflammation, and is converted into a small indurated tumour, varying from the size of a hemp-seed to a horse-bean. It becomes imbedded in the spongy body, -f- According to Sir B. Brodie, the usual situation is about two or three inches from the orifice, but it is sometimes perceptible close to the fr\u00e6num, at others within the scrotum.\nRokitansky mentions a curious form of disease occurring after repeated attacks of go-norrhoea. \u201c The urethra presented numerous cartilaginous protuberances, from the size of a millet-seed to that of a pea, in part coalescing, and scattered over the inner surface as far back as the bulb, leaving the passage, however, of adequate dimensions.\u201d J\nObstruction from other causes. \u2014 The urethra is sometimes occupied by veiTucous vegetations, the result of gonorrhoea. Numerous instances of this are given by Ricord ; they are usually found near the meatus, and are remarkably vascular; but sometimes they exist in the membranous, or even the prostatic, portion. They are distinguishable by their greater vascularity from another form of excrescence or caruncle, w'hich co-exists occasionally with stricture. Both, however, are formed in consequence of irritation of the urethral membrane, and represent simple oi*-ganised structures connected with the urethra by a base or stem.\nHunter met with two, and these were in cases of very old stricture, where the urethra had suffered considerably. Home says, that with all his opportunity in inspecting these diseases in the dead body, he never met with them. Rokitansky () also affirms their exti\u2019eme\n* See Edinburgh Monthly Journal for April, 1850, p. 367.\n\u25a0j- Home, On Strictures.\nI Rokitansky\u2019s Pathology; Sydenham Society\u2019s edition, vol. ii.\n\u00a7 Loc. cit.","page":1262},{"file":"p1263.txt","language":"en","ocr_en":"URETHRA.\n1263\nrarity. Chelius * says, \u201c they are found as little masses of soft warts behind the stricture ; at other times they are found before the stricture ; they are similar to those growths observed on the prepuce and glans. I have seen in one person, who had frequent claps, the urethra filled with round excrescences from an inch behind the fossa navicu/aris\u201d Morgagni found one in a case of stricture, f-\nThese excrescences are developed from the mucous membrane as the result of simple as well as specific irritation, and are limited in the extent of their growth by the walls of the canal.\nWe sometimes meet with a more perfectly organised structure in the urethra in the form of polypi. They, however, are by no means common. Rokitansky met with one in the prostatic part of the urethra, in which situation they are usually found.\nIn the Museum of the Royal College of Surgeons there is a preparation (2578 ) of the urethra of an ox, with a large polypus hanging from the verumontanum.\nIrritable Urethra. \u2014 This condition may be recognised by the following symptoms : there is slight increased vascularity of the canal as indicated by the redness of the meatus : the lips of the meatus are glued together in the morning by mucus, slightly tinged : there is a very trifling discharge, scarcely sufficient to discolour the linen ; this is increased by indulgence in wine ; a sense of uneasiness is perceived along the canal, and this extends to the testicles and the rectum. The patient has a more frequent desire than natural to pass his water, the stream is diminished, and a scalding sensation is experienced at the extremity of the glans whilst the urine is passing. These symptoms are exacerbated by indulgence in venereal pleasures, and are often associated with increased acidity of the urine ; not unfrequently pain is experienced down the thighs in the course of the nerves, and the patient suffers a slight febrile attack. This state exists, very frequently, altogether independently of gonorrhoea, and appears really to result from a mental cause, the patient being strongly impressed, after a suspicious connection, with the idea of impending gonorrhoea. Under the use of diluents and the warm bath this disease very generally passes off. The true pathology of this state I believe to consist in an increased vascularity of the urethra and its follicles, with a similar condition of the glands of Cowper and the prostate, under the influence of nervous irritability.\nThe prostatic part of the urethra is liable to irritation from long continued masturbation. The orifices of the ejaculatory ducts are the special sources of this irritation, but the general mucous surface around partakes of the disease.\n.Neuralgia of the Urethra.\u2014 The urethra and neck of the bladder are consentaneously affected in this disease. The periodic and\n* Chelius\u2019 Surgery, translated by South, vol. li. p. 856.\nf Liv. xix. ch. 23.\nremittent forms of neuralgia attack the urethra : the periodic disease is characterised by deep shooting pains in the canal extending over the loins and sacrum, and down the thighs, occurring in paroxysms, and generally accompanied by sudden and urgent desire to micturate. The attacks recur at a certain hour, generally night and morning, or every second or third day, and during the intermissions the patient is altogether free from pain.\nThe urine is thrown out in jets, and sometimes stops suddenly, and many of the ordinary symptoms of stone in the bladder are present, and hence the great importance of the diagnosis, for there is no doubt that, under this condition, many patients have been subjected needlessly to the operation of lithotomy. The sound alone can decide the question. This disease may originate entirely from the ordinary causes of neuralgic affections, or it may depend on local causes, as the use of stimulating injections, the frequent use of the catheter, constipated bowels, worms in the rectum : it is often associated with acrid urine, and either leads to, or is accompanied with, hypertrophy of the detrusor urince.*\nIn the female. \u2014 The female urethra is a short tube by which the urine alone is excreted. It commences at the neck of the bladder, and terminates at the meatus urin-arius. The direction of the urethra in the female is similar to the first or pelvic division of that of the male ; thus it descends slightly, and, passing forwards, in nearly a straight direction, beneath the pubis, it makes a gentle ascent just at its termination : it therefore forms a curve, the concavity of which faces upwards, the convexity downwards, towards the anterior wall of the vagina, in which it appears imbedded, and to which it is so closely connected, that it is almost impossible to separate one from the other. In its course it perforates the triangular ligament, which is stretched across beneath the arch of the pubis, and is but an imperfect representative of the corresponding part in the male. The urethra thus forms the first and smallest of the three outlets beneath the pubis.\nThe commencement of the urethra is situated within the pelvis, behind the symphysis pubis, to which it is suspended by the apparatus which supports the neck of the bladder : its next division is directly beneath the inferior pubic ligament, and is connected to it by condensed cellular membrane : the last portion of the urethra passes between the origins of the crura clitoridis, and terminates by a rounded aperture at the anterior part of the vagina, and a little in front of the pubic arch : this aperture is called the meatus urinarius.\nThe female urethra is invested by a muscular apparatus, analogous to that surrounding the membranous portion of the male canal : thus Santorius described some tranverse and circular fibres connected with this part, the latter being situated deepest, and the former\n* Rowland, On Neuralgia.","page":1263},{"file":"p1264.txt","language":"en","ocr_en":"1264\nURETHRA.\npassing over the canal, and termed by him \u201c the depressor urethrae.\u201d So also often vertical fibres can be distinguished^rising from the back of the symphysis pubis, and analogous to Wilson\u2019s Muscles, in the male. Guthrie * also has given a representation of a muscle arising from the rami of the pubis, and splitting into an upper and under part, and thus completely surrounding the tube, as the muscle known by the name of \u201c Guthrie\u2019s muscle\u201d does in the male : this apparatus in the female can only have the effect of effectually closing the canal. The length of the female urethra varies from an inch and a half to two inches; but its diameter is considerably greater than that of the male urethra : thus at its commencement, at the neck of the bladder, it is nearly half an inch in diameter, but it is nearly cylindrical in the remainder of its course, and does not exceed three or four lines in diameter. It is contracted at the meatus urinarius. There are few points of higher practical importance in reference to the surgery of the urinary organs of the female than the extreme dilatability of the urethra. It is well understood that, by the introduction of sponged tents or other mechanical contrivances, gradually increased in diameter, this canal may be so far dilated as readily to permit the extraction of urinary calculi of at least an inch and a half in diameter ; and hence the operation of lithotomy is almost superseded by the more simple procedure of extracting the stone by dilatation.\nThe orifice of the urethra or meatus urinarius is situated above and in front of the entrance of the vagina, at the further end of the vestibulum, between the nymph\u00e6, and anterior to the hymen in the virgin: it is placed at the distance of an inch from the clitoris. To the eye it presents the appearance of a closed circular aperture, slightly raised and thickened at its under edge, with a depression in its centre. Without ocular inspection, it may be found by carrying the fore finger below the clitoris, down along the symphysis pubis for a short distance, when it can be distinguished by its forming a soft semicircular projection, and its corresponding depression can be readily felt. Under examination with the finger the projection of the meatus increases as if by erection, and thus at once becomes more perceptible to the touch : the inferior lip of the meatus is continuous with the anterior mesian column of the vagina, and contains within it some large mucous crypts ; this was formerly termed the corpus glandulosum. In order to avoid torching the clitoris, which, as a matter of delicacy, is of no slight importance, the meatus may be easily found without exposure, by carrying the finger into the vagina, along the anterior wall of which an elongated spongy swelling will be perceived ; by advancing the finger along this swelling the meatus may be readily reached.\nIf the urethra be laid open, its mucous\n* Guthrie on Diseases of the Bladder, &c., pp. 47, 48.\nmembrane is seen thrown into longitudinal plicae, with valleculas or depressions between them. Some of the plicae are larger than the rest : there is usually one large fold along the posterior wall of the canal, and one on either side ; the fold at the back part, after passing for a short distance, generally divides into two branches : it has been compared to the caput gallinaginis in the male. Besides these there are other folds, which, when the urethra is closed, dove-tail into corresponding depressions. The mucous membrane is of a rosy tint at the meatus, but becomes paler towards the bladder : it is copiously supplied with mucous follicles. These open generally in the depressions between the rugae ; but there are some large depressions or crypts, into which numerous smaller follicles open, situated just within the meatus : these equal in size the blunt end of and ordinary probe ; they are imbedded in the under labium of the meatus, and, forming a considerable, projection, constitute the corpus glandulosum of some authors. So also, in the vicinity of the commencement of the urethra, there is a collection of large lacunae visible : indeed the under part of the mucous membrane is at this part studded with small orifices of mucous crypts. These are evidently different from the ordinary lacunae of the urethra : the latter are analogous to those of the male canal, and, being situated between the longitudinal plicae, open obliquely forwards. They are the seat of a copious mucous secretion.\nThe mucous membrane within the meatus is slightly depressed at its floor, which gives the urine a direction forwards and upwards. The whole canal is surrounded with a plexus of numerous small veins, mixed with a considerable quantity of elastic or contractile tissue (the corpus spongiosum) ; hence the female urethra possesses the undoubted attributes of an erectile structure.\nOrganization.\u2014The organization of the female urethra is analogous to that of the male : it is essentially a mucous canal, belonging to the genito-urinary division of mucous membranes, and is composed of a mucous layer, covered externally by a layer of contractile tissue. The mucous layer is formed of the ordinai\u2019y basement membrane, covered with a dense pavement epithelium, formed of broad, oval, and conical, compressed cells. External to this is a layer of that remarkable tissue described by K\u00f6lliker as entering so extensively into the structure of the male urethra, as well as all the other mucous outlets of the body ; this is necessarily much more simple in its arrangement than the corresponding layer of the male urethra, and is continuous with some of the longitudinal muscular fibres of the bladder.\nThe arteries supplying the urethra are derived from the inferior vesicle, the uterine, and vaginal.\nThe veins terminate in the pudic or branches of the internal iliac.\nThe lymphatics terminate in the hypogastric ganglia.","page":1264},{"file":"p1265.txt","language":"en","ocr_en":"URETHRA.\t1265\nIts nerves arise from the puclic .and the hypogastric plexus of the sympathetic.\nProstate gland of the female. \u2014 Has the female a prostate ? Guthrie, in his work on \u201c Diseases of the Bladder and Urethra,\u201d assigns a prostate to the female, which, according to him, has a form like that of the male prostate, and nearly a similar structure. He says it surrounds the commencement of the urethra. He further states it to be the size of the prostate of a boy before the age of puberty ; and rather regards it as existing in a rudimentary form than as an organ possessing any follicular or glandular structure. He considers it as of use in giving the urethra support, and as affording a fixed point for the action of some of the muscular fibres of the bladder.\nGuthrie quotes the authority of De Graaf, \u201c De Mulierum Organis,\u201d in support of his opinion. \u201c Sed ulterius, inquiret aliquis, unde illi ductus sive lacunce humorem ilium hauriant ? priores ill\u00e6 scilicet, quocirca colli orificium et meatus urinarii exitum conspiciuntur ex parasta-tis mulierum seu potius crasso et memhranoso corpore circumcirca meatum urinarium existente humorem suum accipiunt ; posteriores vero ex nervoso~membranosd colli uterini substantia liquo-rem suum colligunt.\u201d\nDe Graaf, however, refers to that mass of follicles surrounding the meatus and commencement of the urethra, rather than to any special organ worthy of the designation of prostate. Cowper also denominates the mass of follicles surrounding the meatus as the \u201c corpus glandulosum.\u201d\nI confess that I have not been able to trace a prostate in connection with the female urethra : there is, however, generally found a firm mass around the canal, which is much thicker at the under part than at the upper, and to which I believe Mr. Guthrie refers. It is certainly not muscular; but it does not present evidences of glandular structure ; containing merely a large quantity of areolar and elastic fibre. According to the notions of the homologies of the male and female now prevalent, the prostate should be represented in the female by a rudimentary structure in connection with the uterus rather than the urethra, inasmuch as it is essentially a sexual organ, and developed in the embryo from the protometra.\nPathology. \u2014 The female urethra is wanting where the entire uropoietic system is absent, as also when the bladder is deficient : it is also wanting in cases of ecrophy of the female bladder, and in cloacal formation.\nIn consequence of arrest of development, it may terminate in the vagina, or may receive the vagina or rectum at the posterior part.\nSometimes the urethra is abnormally dilated, as a congenital malformation.* This is rare : it is more frequently dilated after the removal of calculi, &c., from the bladder. Rare instances have been known in which the act of copulation has been performed through the urethra instead of the vagina.\n* Rokitansky\u2019s Pathological Anatomy, vol. ii., Sydenham Society\u2019s edition.\nVOL. IV.\nPreternatural contractions of the urethra sometimes occur from pressure of the displaced uterus or the prolapsed vagina: they sometimes arise, as in the male, from inflammation, and constitute true stricture of the canal : this is exceedingly rare.\nThe urethra deviates from its normal direction in prolapsus of the bladder and uterus ;\u2014 it takes on more or less of a serpentine direction ; \u2014 this distortion of the canal not unfre-quently gives rise to retention of urine. As the uterus enlarges during pregnancy the bladder is carried upwards, and, with it, the urethra is slightly raised.\nThe urethra may, however, be excessively dilated without incontinence of urine, of which an instance has come to my own knowledge. A woman of the town was admitted into the London Hospital, in consequence of retention of the menses : she had imperforate hymen ; the urethra was enormously dilated, and no doubt she had admitted sexual intercourse through. She had no incontinence of urine.\nDr. Chamberlain also met with a case of imperforate hymen, where the urethra admitted the forefinger.* Dr. Oldham has observed the same in atresia vaginae, unattended with incontinence of urine.\nThe urethra suffers a partial or total inversion, forming a tumour at the vulva, attended with difficulty and pain in voiding urine.\nM. Sernin mentions the case of a girl eleven years of age, who experienced difficulty in making water. He examined her after a violent attack, and found a cylindrical body, four inches long, hanging from the vulva ; and whenever she attempted to make water this projection swelled up. Jt was removed with success. It was presumed to be an inverted urethra.'!'\nThe female urethra is liable to injuries of various characters : the most common are simple contusions and lacerations, or it may be divided partially or completely by cutting instruments. The urethra frequently suffers contusion with the neck of the bladder in cases of protracted labour, from pressure of the child\u2019s head against the pubis. Under these circumstances sloughing often succeeds, and a fistulous communication between the urethral orifice of the bladder and vagina results, leading to incontinence of urine.\nLacerations of the female urethra are very uncommon, and require no particular observations ; a simple retention of the parts by suture would be advisable to secure their re-union.\nSimple incisions of the urethra, as in the operation of lithotomy, generally reunite successfully : this, however, is not invariably the result, and hence the occasional occurrence of incontinence of urine. The urethra, although extremely dilatable, is occasionally stretched beyond its natural capacity, in the removal of\n* See also Portal, Cours d\u2019Anat. M\u00e9d. vol. iii. p. 476.\n+ Recul. Period, tom. xvii. p. 304.\n4 M","page":1265},{"file":"p1266.txt","language":"en","ocr_en":"1266\tURETHRA.\ncalculi or foreign bodies from the bladder, and thus becomes paralysed, and never afterwards recovers its normal tone. This is an unfortunate condition, as it admits of no remedy.\nThe female urethra is occasionally the seat of inflammation : this is almost invariably of the catarrhal form, and may arise spontaneously or as the consequence of gonorrhoea. The follicles at the meatus are especially liable to inflammation, in conjunction with the follicles of the vulva and margins of thenymphae. The disease is described by l)r. Oldham under the head of the \u201c Follicular Inflammation of the Vulva.\u201d It consists of a number of slightly raised vascular points, clustering around the elevated border of the orifice of the urethra, and skirting the margins of the nymph\u00e6. The points are isolated and small ; but, as the disease progresses, several of them coalesce, and here and there a minute speck of ulceration may be seen in their centre ; but little or no swelling accompanies it.\nDr. Ashwell has recognised the same disease, and concludes that the same is alluded to by Dr. Churchill, where he speaks of \u201c a more circumscribed inflammation which may attack any portion of the vulva, and is often seen merely surrounding the orifice of the urethra, and occasionally confined to the clitoris.\u201d *\nSpecific inflammation of the urethra is usually the consequence of gonorrhoea. The disease seldom attacks the female urethra until after the vagina has been some time affected. It is easily recognised by a swelling or pouting of the meatus ; and on pressing upwards against the pubis the true gonorrhoeal discharge appears. It is accompanied with a sense of scalding on micturition and pain ; but the symptoms, for obvious reasons, are much milder than in gonorrhoea of the male. It is amenable to the same treatment.\nTumours of various kinds are occasionally found connected with the meatus and the urethra itself ; the former have their seat especially in the inferior labium of the urethral orifice. The most common is the simple vascular tumour, first described by Morgagni as \u201c a red fungous excrescence, the size of a bean, sometimes to be observed [attached to the orifice of the urethra.\u201d It has since been recognised by others ; and has been well described by Sir Charles M. Clarke. Sir C. Clarke describes it as a vascular tumour, arising from the meatus urinarius. \u201c Its texture is seldom firm ; it is of a florid scarlet colour, resembling arterial blood, and if violence is offered to it, blood of the same colour is effused. It is exquisitely tender to the touch, and if an accurate examination of it be made, it appears to shoot from the inside of the urethra. Its attachment is so slight that it appears like a detached body lying upon the parts.\u201d It is sometimes connected higher up with the urethra, and can then only be brought into view by introducing a catheter or\n* Ashwell, on the Diseases of Women.\nprobe, and separating forcibly the walls of the urethra, when it will be found attached to the mucous membrane.\nMr. Hughes, of Stroudwater, described a tumour \u201c of a red colour, and of a soft, spongy texture, with an irregular, jagged surface, connected with the meatus.\u201d He removed the meatus, which completely included the disease.\nCarcinomatous tumours are also met with in connection with this part. They have been described by Boivin and Dug\u00e8s. They are frequently associated with similar diseases of the uterus. They are generally of the ence-phaloid character, present a lobulated appearance, and are exceedingly painful. If unaccompanied by disease of other organs, they can be successfully removed.\nFungoid tumours of the malignant class spring occasionally from the mucous membrane of the urethra. After excision they have a great tendency to recur. They are occasionally associated with a similar disease of the bladder.\nThe urethra sometimes becomes thickened along its whole extent. According to Clarke, this thickening exists principally in the cellular membrane surrounding the urethra, and is accompanied by a varicose state of the circumjacent veins. On examination, a bulbous tumour will be found behind the pubis, and if much pressure is made upon it, pain will be produced, but not of a severe kind.\u201d* It is accompanied with a mucous discharge from the urethra and vagina. The vessels on the surface of the tumour become so large as to admit of being opened with a lancet. When the patient is erect the size of the vessels increases, and they diminish in the recumbent position. Sometimes a pouch forms in the urethra, in which a few drops of urine are lodged : this can be emptied by pressure with the finger. The mucous membrane covering the tumour is sometimes thick, occasionally thin and shining. The disease occurs principally in married women who have had children ; and, according to Clarke, in those with red or auburn hair and fair complexions. The disease seems to consist of an enlargement of the veins of the part, with hypertrophy of the cellular membrane.\nThe female urethra is rarely the seat of stricture. I have made inquiries of some of the most experienced accoucheurs in London, and they agree that stricture of the female urethra is very rare. The circumstance clearly depends on two causes ; the first is the extreme natural dilatability of the urethra in women ; and the second is, that, although it is liable to gonorrhoeal inflammation, the disease does not persist long in the canal, and consequently its tissues are not involved in protracted chronic inflammation, as is so common in the male.\nSir Benjamin Brodie, however, met with a case of stricture in the female urethra : it commenced at the extremity of the canal,\n* C. M. Clarke, on some of the Diseases of Females.","page":1266},{"file":"p1267.txt","language":"en","ocr_en":"URETHRA.\t'\tI2G7\nand extended half an inch back, and was so tight that it scarcely admitted the finest probe. My friend Carling also met with a case of stricture, attended with retention of urine. Being foiled in the introduction of the catheter, he was compelled to puncture the bladder in the direction of the canal beneath the pubis. The disease had arisen from the contusion to which the urethra had been subjected in a protracted labour, which had taken place twenty-eight years before. Since that time the woman had always experienced difficulty in making water, and had twice suffered retention, but no catheter could ever be passed. The aperture of the meatus was large, and there was great induration around : a small catheter was passed about an inch and a half, but could not be made to enter the bladder. The bladder was punctured, and between thirty and forty ounces of urine drawn off. The stricture was afterwards dilated with bougies.\nCOMPARATIVE ANATOMY.\nThe comparative anatomy of the urethra has been most carefully examined by Cuvier ; and I have borrowed largely from his celebrated Le\u00e7ons d\u2019Anatomie Compar\u00e9e, in my description.\nCuvier divides the \u2018urethra into two portions; the first extends from the orifice of the bladder to a short distance anterior to the prostate, whilst the second is continued thence to the orifice at the glans.'l\nIn the first portion of the canal in mam-miferous animals generally,\u2014that is, in what is termed in man the prostatic portion, we find the verumontanum surrounded by prostatic ducts and terminations of vasa ejaculatoria ; whilst in many the sinus prostaticus is of an enormous size : this is especially the case in the elephant.\nIn many animals we find temporary longitudinal folds of membrane : these are, however, permanent in some, as in the marmot : in this animal as many as twelve pass off on each side, and, enclosing small spaces, render the canal exceedingly irregular, and thus retard the flow of urine and semen.\nWith respect to the comparative length of this part of the canal there is great variety. Thus in man and the apes it is short, and surrounded by the prostate.. In the makis it is long and slender; it is long m the Cheiroptea ; and of medium length in the bears. In the hedgehog it is about one third the entire length; it is more than half in the civet, cat, sarigue, kangaroo, and. phasco-lome ; it scarcely reaches this length m the giant kangaroo ; and is of less , extent in the dog. It is actually longer, and its diameter is larger, in the marmot ; scarcely half the length in the rat and guinea-pig; somewhat less than half in the hare; short, and not a quarter of the entire length in the squirrel; it is not more than a third or fourth in the elephant, Pachydermata, Solidungula, Ruminants, the dolphin, and porpoise. It. is usually relatively shorter in man and theapes than in all\nother mammiferous animals ; and it is amongst the Carnivora, in whom the penis is comparatively short, as the cat and civet, that it appears to bear the largest proportion to the other part of the canal. Cuvier denominates this pelvic part of the canal the muscidar portion, because it is usually surrounded by a muscular layer. Thus in man and the apes this is especially remarkable on the sides of the prostate, where the levator ani and levator prostate are situated.\nIn the rest of the mammifera the muscular layer is circular. In the Cheiroptera, mole, hedgehog, and cat, it is remarkably thick ; in the dog, civet, and sarigue it is thin ; it is scarcely perceptible in the marmot, where there is scarcely any thing more than a tendinous covering. In the Rodents it is generally of moderate thickness ; but in the Pachydermata and Ruminants it is of great thickness.\nCuvier suggests that the object of this muscular layer is to expel the urine and seminal secretion, by forcibly contracting the first portion of the urethra ; and hence it is found so fully developed in those animals whose penis is long, as in the Ruminants, and in those in whom that organ is short, as in the cat ; for in the first it is requisite to force the fluid along the lengthened penis, in the latter it becomes necessary to expel it beyond the limits of the penis. He says that this species of ejaculation is requisite, when any obstacle exists in the urethra, to the free discharge of semen, as is the case in the porpoise and the dolphin, where the membranous part of the urethra, being wholly surrounded by the prostate, forms an acute angle with the remainder of the canal, and becomes considerably contracted at that part. In these animals there is a thick muscle, attached behind to the front of the corpora cavernosa ; the fibres of which, directed backwards, cover the prostate gland, and pass as far as the under part of the neck of the bladder. The office of this is necessarily to overcome the difficulty in the expulsion of the contents of the urethra, arising from the peculiarity just mentioned.\nIn many animals, as in the Ruminants and Pachydermata, the communication between the former part of the urethra and the second or spongy portion is by no means direct ; but it takes place at the superior part of the latter by a sort of opening at a short distance from its commencement : this is the case also in the wild boar. The spongy portion begins under this condition in the form of a cul-de-sac of varied diameter,\u2014a sort of bulb,\u2014into which the semen is received after it has traversed the muscular portion of the urethra, whilst the secretion of Cowper\u2019s glands escapes into its sides. In other cases, as in the squirrels and marmots, this cul-de-sac receives only the orifices of these glands, and continues in the form of a short canal, which opens into the urethra either at the middle of the penis, or at a short distance beyond. The urethra in this instance passes over it, and they are both surrounded by the vascular tissue investing the bulb.\n4 m 2","page":1267},{"file":"p1268.txt","language":"en","ocr_en":"1268\nURINE.\nAccording to Owen, in the Jcangaroo the combined prostatic and membranous or muscular part of the urethra is proportionally longer and wider in the marsupial than in any other mammiferous quadrupeds. It swells out immediately beyond the neck of the bladder, and then gradually tapers to its junction with the spongy part of the urethra ; it is not, however, divided like the vagina. Its walls are thick, formed of an external thin stratum of nearly transverse muscular fibres, and a thick glandular layer, the secretion of which exudes by innumerable pores upon the lining membrane of this part of the urethra.*\nThe urethra in the Monotremata approximates in many of its characters to that of the bird. \u201c It begins by a small orifice at the root of the penis, near the termination of the pro-genital passage, and, by the action of certain muscles, it can be brought into closer approximation with the uro-genital passage.\u201d Owen supposes that this temporary continuation of the urethra and uro-genital passages takes place during the vigorous muscular and vascular actions of the parts in coitu, and that the semen is then propelled from one along the other without escaping into the common ventricular compartment of the cloaca According to Cuvier, in the Gerboise de Mauritanie the spongy portion of the urethra does not join the corpora cavernosa until it reaches the glans.\nFor the comparative anatomy of the urinary apparatus in birds, reptiles, and fish, see the separate articles on these subjects.\nThe urethra in the females of the lower animals offers no peculiarity worthy of notice.\nBibliography.\u2014Male.\u2014On the anatomy of the urethra, see various anatomical works ; and on the muscles surrounding the membranous portion, see Wilson, on the Structure and Diseases of the Urinary Organs ; and Guthrie, on Diseases of the Bladder and Urethra. Daran, Observations Chirurgicales sur les Maladies de l\u2019Ur\u00e8tre, trait\u00e9es suivant la nouvelle M\u00e9thode. Paris, 1748. Gu\u00e9rin, Dissert, sur les Maladies de l\u2019Ur\u00e8tre, avec des R\u00e9flexions sur la m\u00e9thode qu\u2019ont employ\u00e9e jusqu\u2019\u00e0 pr\u00e9sent les Praticiens. Paris, 1780. Hunter, on the Venereal Disease. 2nd Edition. 1788. Whately ( Thomas'), An Improved Method of treating Strictures of the Urethra. London, 1801. Labraud, Sur le R\u00e9tr\u00e9cissement Chronique de l\u2019Ur\u00e8tre. Paris, 1805. Home, Practical Observations on the Treatment of Strictures of the Urethra. 1805. Kleeman, Dis-sertatio de curandis Urethrae Chronicis. Erlangen, 1811. Howship ( John), Practical Observations on the Diseases of the Urinary Organs, &c. London, 1816. Desault, Maladies des Voies Urinaires (\u0152uvres Chirurgicales, vol. iii.). Paris, 181*3. Arnott (James), M. D., A Treatise on Strictures of the Urethra, containing an Account of an improved Method of Treatment. London, 1819. Bell (Charles), A Treatise on Diseases of the Urethra, &c. &c. 3rd Edition, by Shaw. London, 1822. Ducamp, Trait\u00e9 des R\u00e9tentions d\u2019Urine caus\u00e9es par le R\u00e9tr\u00e9cissement de l\u2019Ur\u00e8tre, &c. Paris, 1822. Lisfranc, Des R\u00e9tr\u00e9cissements de l\u2019Ur\u00e8tre. Paris, 1824. Lallemand, Observations sur les Maladies des Organes G\u00e9nito-Urinaires. Paris, 1825-27. Winz-heimer, Ueber die Organische Hamr\u00f6hrenverenge-rung und tdie verschiedenen Untersuchungs- und\n* See article Marsupialia. i\nf See article Monotremata.\nHeilungs-Methoden derselben. Erlangen, 1832. Amussat, Le\u00e7ons sur les R\u00e9tentions d\u2019Urine caus\u00e9es par le R\u00e9tr\u00e9cissement du Canal de l\u2019Ur\u00e8tre, &c. 1832. Tanchon, Trait\u00e9 des R\u00e9tr\u00e9cissements du Canal de l\u2019Ur\u00e8tre. 1835. D. J. Arntzenius, De Organische Gebrechen der Urethra. Utrecht, 1840. Brodie (Sir Benj.), Lectures on the Diseases of the Urinary Organs. 3rd Edition. 1842. Kugler, Praktische Abhandlung \u00fcber die Verengerung der Harnr\u00f6hre, und ihre Heilung ohne Aetzmittel. Wien, 1843. Guthrie, On the Anatomy and Diseases of the Neck of the Bladder and of the Urethra. London, 1834. Civiale, Sur les Maladies des Organes G\u00e9nito-Urinaires, 1850.\nFemale. \u2014 For the anatomy of the female urethra, see the various works on Descriptive Anatomy. \u2014 For the morbid anatomy, the following works may be referred to : Morgagni, De Sedibus et Causis Morborum ; Churchill, On the principal Diseases of Females, 1844, in which reference is made to the writings of Warner, Jenner, Sir C. M. Clarke, Wardrop, Velpeau, Hosack, Rosenm\u00fcller, V ogel, Kal-debrand, and Drokaska : also to Hughes, in Medical Facts and Observations, vol. ii. p. 26. ; to the Lancet, vol. xiii. p. 784.; to the Journ. Hebdom., July, 1836 ; to the New York Journal of Medicine and Surgery, No. 1. p. 29. ; to Dug\u00e8s, on Diseases of the Uterus (Heming\u2019s Trans.), p. 546. ; and the fourth volume of the Transactions of the Provincial Medical and Surgical Association. The Principles of Midwifery, &c., by John Bums, Glasgow, 1820. Dr. Ramsbotham\u2019s Lectures on Midwifery, Med. Gazette for June 6th, 1835. The British and Foreign Medical Review, vol. viii. 1839. Grosse\u2019s Pathological Anatomy, vol. ii. 1839. Dr. Ashwell, On Diseases of Women, 1846.\nJohn Adams.\nURINE. \u2014 Lat. Unna ; Gr. ro' ovpov ; French, VUrine; ltal. V Urina; Germ, das Harns.\nThe urine may be defined as that fluid which is eliminated by the kidneys in the discharge of their excretory function.\nThe human urine being that of an omnivorous feeder, differs materially from that which is excreted by animals purely carnivorous or herbivorous. In cases occasionally met with, however, where, either from congenital taste, want, or the indulgence of eccentricity or curiosity, vegetable food alone has been taken by human beings, the urine has been observed to undergo certain modifications as a consequence.\nThe urine, it is obvious, must vary much in constitution, according to the conditions under which the organism is placed, both in respect to external and internal circumstances. Thus the state of the atmosphere, as respects heat and cold, dryness and moi\u00e2ture, will affect the quantity of water excreted, as a constituent of the urine, while the quality and quantity of the ingesta, the state of the chylo-poietic organs, and the amount of exertion to which the body has been subjected, are all causes tending to modify the amount, and perhaps also the nature and quality, of the solid matters excreted by the kidneys.\nWhen treating, therefore, of the chemistry of normal urine, it must be borne in mind that, in fixing a standard, we are but giving a result more or less approaching to the truth, and that the real method of obtaining a philosophical view of its chemical constitution is, to regard the urine in its variations, in the","page":1268},{"file":"p1269.txt","language":"en","ocr_en":"URINE.\n1269\nhope of obtaining some fixed law whereon to base a knowledge of the peculiar influence of the several circumstances on which the variations depend.\nThe chemical analysis of this complex fluid was undertaken by Berzelius, who, with his accustomed accuracy, produced a result in which the various improvements and advances in chemistry have rendered it necessary to make but little change.\nThe number of constituents of healthy urine has been but little increased by discovery since Berzelius wrote, one or two only having to be added to his list.\nIt will be our object to enumerate these constituents, and describe such as may require especial notice, before proceeding to consider the quantitative analysis of the urine.\nThe following, then, may be regarded as a list of the constituents of healthy urine : \u2014\nWater.\nUrea.\nExtractive matters.\nColouring matter.\nMucus.\nUric acid. Hippuric acid. Carbonic acid. Lactic acid. Sulphuric acid. Hydrochloric acid. Phosphoric acid. Silicic acid. Hydrofluoric acid. Soda.\nPotash.\nLime.\nMagnesia.\nAmmonia.\nOxide of iron.\n{Of four kinds, differing in their reactions and solubility in menstrua.\nf Of two kinds, brown, -i (or hc\u00e9maph\u00e6in), and (red (or uroerythrin).\nOther acids, peculiar to urine, have been described by authors, but their qualities are not sufficiently determined to admit ol their being yet classified as constituents.\nUrea. \u2014 This constituent of the urine has been supposed by some to form during the evaporations necessary for its extraction. This, however, is not the case, as I have been able to obtain it by agitating the officinal rectified ether with urine in the natural state, and then allowing the ethereal solution, which separates above the urine, to evaporate spontaneously. The urea so obtained is free from lactic acid, showing that the view of MM. Cass and Henry, who consider urea to exist in urine in the form of lactate, is in all probability erroneous.\nUrea possesses the following ultimate constitution:\u2014\nC2, N2, H4, 02.\nIts chemical properties are as follows : \u2014 When heated on platinum foil it fuses, and. on the heat being urged, it yields fumes ol\ncarbonate of ammonia. It is very soluble in both cold and warm water.\nA concentrated solution of urea will bear a heat of 212\u00b0 Fahr, without decomposition, but it quickly decomposes at that temperature when in dilute solution.\nAlcohol of specific gravity 0*816 dissolves one-fifth of its weight of urea at 60\u00b0 Fahr. ; boiling alcohol dissolves nearly its own weight.\nUrea is slightly soluble in ether.\nThe caustic alkalies boiled with urea decompose it into carbonate of ammonia.\nThe nitric and oxalic acids combine with urea, forming more or less insoluble salts, and on this fact the processes for the extraction of urea, from its combinations, chiefly depend.\nUrea possesses neither an acid nor alkaline reaction. Its crystalline form is that of a four-sided prism.\nExtractive matters of Urine. \u2014 There are four of these extractives; one soluble in alcohol as well as in water, and three soluble in water, and not in alcohol.\nThat which is soluble in alcohol may be obtained from the urine by digesting alcohol of specific gravity 0*833 on an extract of urine, and after crystallising the urea by means of nitric acid from the products of the alcoholic solution dissolved in water, separating the un-crystallisable matter, and neutralising it with earbonate of baryta : the mass must then be dried, and alcohol must be used to separate the extractive from the barytic salt.\nIts chemical properties are as follow : \u2014\nWhen heated, it swells much, and leaves a copious alkaline carbonaceous mass.* It reddens litmus paper.\nNeither bi-chloride of mercury, nor the acetate of lead, is capable of precipitating its watery solution.f\nBoth acid and alkaline solutions are incapable of effecting any precipitation of this extract from its solution in water.\nProtochloride of tin, nitrate of silver, and di-acetate of lead, produce precipitates.\nIt may be well to mention, that if anhydrous alcohol be digested on this extractive, which has been called osmazome,it is capable of being divided into two portions; the one soluble and the other insoluble in that fluid.\nThe property of being precipitated by the di-acetate of lead, nitrate of silver, and protochloride of tin, belongs peculiarly to that part of the extractive matter which is soluble in anhydrous alcohol.\nAnimal extractive soluble in water only. \u2014 This may be procured by dissolving in water an extract of urine, which has been digested with alcohol of specific gravity 0*833. By the re-solution we separate any vesical mucus, lithic acid, earthy phosphate, or silica, which may be contained in the mass. The solution\n* It contains an alkaline lactate.\nf If these salts produce a precipitate, it is because alcohol has been used of higher specific gravity than 0'833.\n4 u 3","page":1269},{"file":"p1270.txt","language":"en","ocr_en":"URINE\n1270\nis now precipitated with acetate of baryta> in order to rid it of sulphuric acid. The sulphate of baryta is collected on a filter, and the filtered liquor neutralised with ammonia, and then again thrown down with the acetate, which now causes a precipitate of phosphate of baryta.* This is to be collected, and the filtered liquor evaporated in order to drive off the ammonia ; or, what is better, it may be neutralised by acetic acid. Neutral acetate of lead is now added to the solution, which causes a copious precipitate. This must be collected and washed, and then decomposed by sulphuretted hydrogen, which precipitates sulphuret of lead, and leaves the animal extractive in solution. This may be obtained by evaporation. This extractive is, however, but part of that meant to be understood as the \u201canimal extractive soluble in water only,\u201d so often mentioned in analyses. The remainder of it may be procured by precipitating the liquor (in which the precipitate by neutral acetate of lead subsides), by means of the di-acetate of lead ; then collecting the precipitate, decomposing it as before by sulphuretted hydrogen, and procuring the extractive from the clear liquor. It must be remembered that each of these extractives has peculiar properties, perhaps dependent on the processes used to obtain them. There is also a portion of animal extractive left unprecipitated by the di-acetate of lead. It is easily obtained from the liquor by ridding the solution of any lead which may exist in it by means of sulphuretted hydrogen, filtering, and then evaporating to dryness.\nIt is a mixture of these three peculiar extractives which constitutes the \u201canimal extractive soluble in water only\u201d of Berzelius.\nThe properties of the extractive matter precipitated by the neuti*al acetate of lead are as follows : \u2014\nIt is of a brownish colour, translucid, and does not deliquesce ; has no taste, and scarcely affects litmus paper.\nIts solution is rendered cloudy by corrosive sublimate, and more so by the protochloride of tin.\nThe extractive pr\u00e9cipitable by the di-acetate of lead has the following properties :\u2014\u25a0\nIt is of a yellowish brown colour ; it has a slightly bitter taste, and does not deliquesce.\nThe watery solution of this extract is of a deep yellow colour.\nIt is not pr\u00e9cipitable by the solution of bichloride of mercury ; but the protochloride of tin, the di-acetate of lead, and nitrate of silver precipitate it of a dark brown colour.\nThe third extractive, which was precipitated neither by the acetate nor di-acetate of lead, possesses the following characters : \u2014\nIt is of a yellow colour. Solutions of bichloride of mercury, protochloride of tin, and nitrate of silver precipitate its aqueous solution. The precipitate produced by the last of\n* Both these precipitates produced hy acetate of baryta contain animal matter, which, in the latter case, is in very considerable proportion.\nthese re-agents is of a dirty yellowish red colour.*\nColouring matters. \u2014 These are two in number, H\u00e6maph\u00e6in or the brown ; and Uroerythrin, or the red.\na. H\u00e6maph\u00e6in.\u2014This is the substance which gives the yellow or brownish yellow tint to urine, and according to its proportion the urine assumes a lighter or deeper colour. According to Scharling, the odour also of the urine depends on this principle. It is soluble in alcohol, and the alcoholic solution reddens litmus. The odour, when concentrated, is said to resemble that of castor. Scharling believes this colouring matter to be an oxide of a radical, to which he has given the name of omichmyle.\n\u00df. Uroerythrin. \u2014 This exists but in very minute quantity in healthy urine ; it attaches itself especially to the lithic acid, being precipitated with that principle on all occasions. It becomes abundant in some forms of disease.\nMucus. \u2014 For the history of this substance see article Mucus.\nUric or lithic acid. \u2014 This acid may be procured from the urine by the addition of a few drops of strong hydrochloric acid, which, after the lapse of some hours, produces a reddish crystalline precipitate of lithic acid. This red colour is caused by an admixture of colouring matter of urine, for pure lithic acid is perfectly white. It may be obtained in a pure state from the red crystals by being dissolved in caustic potash, and then precipitated from its solution by the addition of hydrochloric acid. The precipitate may now be collected, and washed on a filter.\nLithic acid possesses the following chemical properties : \u2014\nIt is insoluble in water.\nIt is easily soluble in a solution of caustic alkali, and precipitated from such solution by the addition of an acid.\nIt is dissolved by nitric acid with effervescence; and, by careful evaporation to dryness, yields a red or rather pink colour, which becomes of a fine violet tint when ammonia is dropped on it, or even when it is subjected to the action of strong ammoniacal fumes. This reaction of ammonia is very useful, inasmuch as it prevents the yellow stain which many animal matters produce with nitric acid from being mistaken for this reaction of lithic acid. In the former case, the ammonia increases the yellow tinge to an orange colour, which is very distinct from the beautiful violet tint of what is now known as murexid.\nBefore the blowpipe, this substance emits a fetid smell of burnt horn, mixed with an odour approaching to that of hydrocyanic acid.\nThe ultimate analysis of lithic acid shows its composition to be C 5, N 2, H 2, O 3.\nHippuric acid. \u2014 This acid is considered by Liebig to be constantly present in human urine.\n* For further examination of these extractive matters, see the article by Berzelius, i\u00bb his Trait\u00e9 de Chimie, vol. vii. p. 380. ; Sur les Mati\u00e8res ind\u00e9termin\u00e9es dans TUrine.\t.","page":1270},{"file":"p1271.txt","language":"en","ocr_en":"URINE.\t1271\nHe states its quantity as equal to that of the lithic acid, in all persons feeding on a mixed diet. This, however, is certainly an over statement. It is present, but in small proportion, in healthy urine.\nThe ultimate composition of hippuric acid is as follows : \u2014\nC 18, II9, N 1, 0 6.\nIt crystallises in four-sided prisms, obliquely truncated.\nWhen heated it gives out an odour resembling that of the tonquin bean.\nLactic acid. \u2014 The lactic acid was first discovered in the urine by Berzelius, who extracted it by the following process : \u2014\nA portion of urine was evaporated to dryness, and alcohol of specific gravity 0*833 boiled on the solid residuum.\nThe alcoholic solution was next evaporated, and the mass dissolved in water.\nThe watery solution was then boiled with a considerable quantity of hydrate of lime, till all ammoniacal fumes (from decomposing urea) were dissipated ; the hydrate of lime now became coloured yellow, owing to the decomposition of animal matter.\nThe colourless solution was filtered, dried, and then treated with alcohol of specific gravity *845. Equal parts of strong sulphuric acid and water were now added, guttatim, to the alcoholic solution, until sulphate of lime no longer precipitated ; the clear liquor being decanted was next treated with carbonate of lead (recently precipitated), and was then filtered and evaporated to dryness.\nThe residue was treated with oxide of lead and a little water, by which means the lactic acid was converted into a sub-salt of considerable insolubility. This was collected, washed with water, and then decomposed by sulphuretted hydrogen. Thus, sulphuret of lead subsided, leaving the lactic acid free in the supernatant liquor, which, by evaporation, yielded it in the form of an acid yellow syrup, exceedingly deliquescent, and incapable of being thoroughly dried by heat.\nIts chemical properties are the following : \u2014\nIt gives out an acrid odour* when heated, and leaves a porous charcoal if the heat be continued. Alcohol dissolves it in all proportions. It is nearly insoluble in ether.\nTts salts are all of a gummy and uncrystal-lisable nature, excepting the lactates of zinc and magnesia, which have been obtained in a crystalline form.\nWhen lactic acid is added to a strong solution of the acetates of magnesia or oxide of zinc, the lactates of those bases are precipitated.\t...\nThe existence of lactic acid, as a constituent of urine, has been denied by Liebig, and the question is as yet far from being satisfactorily settled.\nThe admission made of late by Liebig, however (as the result of his researches on muscle), that lactic acid exists in the juice of flesh, gives great probability to the correctness of Berzelius\u2019s statement.\n* Not unlike that of the tartrates.\nThe other constituents of the urine which 1 have enumerated, require no particular notice in this place ; and for the methods of quantitatively examining the fluid, I must refer to the article Organic Analysis, contained in this work.\nHealthy urine possesses the following physical characters : \u2014 It is of a pale straw colour, limpid and acid ; after standing some hours, it deposits a light, flocculent sediment, composed of mucus. This mucus, as it exists in health, suspended in the urine, does not materially interfere with the transparency of the fluid. The odour of urine is peculiar, and subject to modification from the use of various articles of diet, and remedies. Its specific gravity varies, owing principally to two causes \u2014 the condition of the atmosphere, as affecting the proportion of water exhaled by the skin, and the quantity and quality of the in-gesta taken.\nHealthy urine may, under these considerations, be said to vary in specific gravity from 1004; to 1032 ; while perhaps, under ordinary or average conditions of diet, temperature, &c., we may place its specific gravity at 1015 to 1022.\nQuantitative composition of healthy Urine.\u2014 The quantitative composition of urine must of course vary considerably, owing to the conditions noticed above, as affecting its specific gravity. The following is the result of an analysis made on 1000 parts by Berzelius, on a specimen considered as healthy: \u2014\nWater.............................. 933*0\nUrea ------\t30*10\nFree lactic acid -\t-\t-\nLactate of ammonia\t-\t-\t-1\nExtractive matters (alcoholic and j watery) -\t-\t-\t-\t-J\nLithic acid -----\t1*00\nVesical mucus -\t0*32\nSulphate of potassa\t-\t-\t-\t3*71\nSulphate of soda -\t-\t-\t-\t3*16\nPhosphate of soda -\t2*94\nSuperphosphate of ammonia -\t-\t1*65\nChloride of sodium -\t4*45\nChloride of ammonium -\t1'50\nPhosphate of lime and magnesia -\t1*00\nSilicic acid -----\t0*03\nDr. Bence Jones has experimented very carefully on the acidity of urine in health. His results show that the amount of acidity is always varying. Thus the urine passed longest after food was generally the most acid, and that voided while digestion was going on, much less so, and in some cases even alkaline, though the patient was in perfect health. These conditions pertained, whether a pure vegetable or animal diet was taken. In the case of a pure vegetable diet, however, the decrease in acidity, after taking food, was not so marked as when a pure animal diet was observed; the urine in the latter case.sometimes becoming highly alkaline, but in the former never exceeding neutrality.\nOther analyses of more recent date have 4 m 4","page":1271},{"file":"p1272.txt","language":"en","ocr_en":"1272\nURINE.\nbeen published by the following observers, viz. Marchand, Simon, Becquerel, Lehmann, &c. I shall quote several of these from the work of Franz Simon, which has been excellently translated into English by Dr. Day, for the Sydenham Society.\nSimon analysed two specimens of the urine of a healthy man, 33 years of age. He was of sanguineous temperament. The specific gravity was in the first case 1011, and in the second 1012.\n1000 parts yielded \u2014\nWater Urea Uric acid Alcoholic extractive, free lactic acid Spirituous extractive Extractive, soluble in water only, and vesical mucus\nLactate of ammonia Chloride of ammonium -Chloride of sodium -Sulphate of potassa -Phosphate of soda -Phosphates of lime and magnesia Silicic acid\n\n1st.\n963-20\n12-46\n0-52\n5To'\n2-60\n;}\nG ^ S3 05\nP00\n1-\t03 0-41\n5 20 \" 3-00\n2-\t41\n0-58 a trace\n!>v\u00cb\nCJ 'p,\n2 o\n* i w i\n2nd.\n956-00\n14-578\n0-710\n4-800 - 5-590\n2-550\n7-280\n3-508\n2*330\n0-654 a trace.\nThe urine of the same individual was also examined under three varying conditions, as follow: \u2014A,on rising in the morning, several glasses of water having been drunk the previous evening ; B, water and some coffee taken, and violent exercise had recourse to during two hours, pulse 100, with occasional intermissions ; C, urine voided half an hour after urine B. These urines were all acid; C most so, and B the least. All three specimens were clear, and B the least coloured.\nThe following is the result of the analyses :\nWater\nUrea\nUric acid, extractives, and ammoniacal salts and chlorides\nPhosphate of soda Sulphate of po-~ tassa Phosphates ofl lime and mag- > nesia -\t- )\n\nA.\tB.\tc.\n972*600 8-402\t981*000 7*568\t957-600 15*257\n13-960\t8-618\t19*140\n1-850\t1*250\t2-750\n2-790\t2*200\t5-000\n0-479\t0-264\t0-656\nThe specific gravities of the above specimens were respectively 1010,1008, and 1014.\nLehmann has analysed the urine collected during 24 hours, from a well-fed and healthy young man. The following three results were thus obtained by him: \u2014\n\t\t1.\t2.\t3.\nWater -\t\t937-682\t934-002\t932-019\nUrea\t\t31-450\t32-914\t32-909\nLithic acid\t\t1*021\t1*073\t1*098\nLactic acid\t\t1*496\t1-551\t1-513\nAqueous ex- ] tractive\t-\tJ Spirituous and 1\tf I\t0-621\t0-591\t0-632\nalcoholic ex-\t\t10*059\t9*871\t10-872\ntractives\t- J Lactates Chlorides of so- j\t1 |\t1*897\t1-066\t1*732\ndium and am-\t\t3-646\t3-602\t3*712\nmonium\t-J\t1\t\t\t\nAlkaline sul- ] phates -\t- J\tf\t7*314\t7-289\t7*321\nPhosphate of] soda -\t-J\t\t3*765\t3*666\t3*989\nPhosphates of] lime and mag-\t\t1*132\t1*187\t1*108\nnesia -\t-J Mucus -\t\t0*112\t0*101\t0*110\nThe specific gravities of the urines which yielded these above analyses, judging from the amount of solid content, must have been as high as from 1022 to 1029. This is very high, indeed, as an average of 24 hours.\nThe mean composition of urine is stated by Becquerel as follows:\u2014\u25a0\n\tMean from four healthy Men.\tMean from four healthy Women.\nSpecific gravity\t1018-9\t1015*12\nWater -\t-\t-\t968*815\t975*052\nSolid matters -\t31-185\t24*948\nUrea\t-\t13-838\t10-366\nUric acid\t0-391\t0.406\nFixed salts\t7*695\t6-143\nOrganic matters\t9-261\t8*033\nSimon very properly remarks on the above analyses, that the discrepancies to be observed in the composition of the urine, principally depend on the variation in the proportion of water ; and that if we consider the proportion of each solid constituent to the whole amount of solid matters, the differences will not appear nearly so great.\nThe variations caused in the urine by the ingestion of various mineral substances, and of organic compounds taken either as food or medicine, have attracted the attention of several chemists of eminence. Liebig has theorised freely on this subject, and it is but right that what he has published should be copied into this article, if only as part of the history of the urine, while I would warn the reader carefully to separate in his mind the matters of fact from the theoretical part of the subject, inasmuch as a great deal yet remains to be done. The position of the inquiry is indeed at present such, that further advances may very probably lead us to detect the fallacy of theories which, it is to be feared, the pre-","page":1272},{"file":"p1273.txt","language":"en","ocr_en":"URINE.\t1273\nsent state of our knowledge may permit us to see in too attractive a form.\nLiebig remarks, \u201cWhen the hydrochloric acid (in the stomach) has exercised its solvent action upon the aliments, and the latter have passed into a state of solution, the soda which originally entered the organism in combination with the hydrochloric acid, that is, as common salt, rejoins the hydrochloric acid during the preparation of the chyme, and previous to its transformation into chyle, the soda and the hydrochloric acid thus reunited combine again and form common salt : chyle and lymph have no longer any acid reaction, but, on the contrary, they manifest alkaline properties.\u201d* The alkaline reaction of the lymph, chyle, and blood of man and of the carnivorous animals cannot be owing to the presence of a free alkali, as is evident from the preceding observations ; for the nutriments of man and of the carnivorous, as well as the graminivorous, animals, contain no free alkali, nor any salt formed of an alkaline base and an acid which might be destroyed in the organism by the vital process, and thus cause the alkaline base to be liberated. The blood must contain the same salts as exist in the aliments. With the exception of common salt, nothing is added during the digestion of the aliments. We have seen that this substance undergoes decomposition in the upper part of the digestive apparatus, being resolved into free soda and free hydrochloric acid ; but we have also seen that the liberated soda rejoins the hydrochloric acid during the preparation of the chyme, and previous to the transformation of the latter into chyle ; that is, when the acid has performed its function, viz. the solution of the aliments,\u2014the salt formed by this combination, that is, common salt, has neither an acid nor an alkaline reaction. The salts with alkaline reaction contained in meat, flour, or grain, are alkaline phosphates. It is obvious that the alkaline reaction of the chyle, lymph, and blood of animals feeding upon animal and vegetable substances can only be derived from their alkaline phosphates. The serum of the blood can only be considered as a combination of albumen with an alkaline phosphate ; the fibrin of the blood, or the fibrin of the muscular fibre, is a combination of albumen with phosphate of lime.\n\u201c The bibasic phosphates of soda and of potash are in many respects highly remarkable salts. Although of a tolerably strong alkaline reaction, yet they exercise no destructive action upon the skin, nor upon organic formations. They possess all the properties of the free alkalies, without being such: thus, for instance, they absorb a large amount of carbonic acid, and this in such a manner that acids produce effervescence in a saturated solution of this kind, just as they would in alkaline carbonates. They dissolve coagulated curd of milk or cheese, as well as coagulated albumen, into clear fluids with the greatest\n* Lancet, 1844.\nfacility, just as caustic or carbonated alkalies do. But of still greater importance in relation to the secretion of urine is their deportment towards hippuric acid and uric acid. Hippuric acid dissolves with the greatest facility in water to which common phosphate of soda has been added. Uric acid possesses the same property at a high temperature ; the phosphate of soda, in this process, loses its alkaline reaction completely upon the addition of uric acid and hippuric acid, and assumes an acid reaction. The acid nature of the urine of man, and of the carnivorous and graminivorous animals, is thus explained in a very simple manner.\n\u201c There are but two principal channels through which the salts entering the organism with the aliments can effect their exit from the body, viz. they must either be carried off* in the faeces, or in the urine. The most simple experiments show that soluble salts are carried off by the faeces only when the amount of salt contained in the fluids in the intestines is larger than that contained in the blood. If the amount of salt in these fluids is equal or inferior to that of the blood, the soluble salts are re-absorbed by the absorbing vessels of the intestinal tube, and enter the circulation, and are then removed from the body by the urinary organs and channels. If the amount of salt contained in the intestinal tube is larger than that contained in the blood, the salts exercise a purgative action.\n\u201c If, after previous evacuation of the rectum, a weak solution of common salt (one part of salt to sixty parts of water) be taken by means of a clyster, no second evacuation will take place : the fluid is absorbed, and all the salt is found in the urine. This experiment yields the most convincing results if ferro-cyanide of potassium is substituted for common salt. In this case the first urine excreted after the injection of the saline solution, and frequently even after so short a time as fifteen minutes, contains so copious an amount of ferrocyanide of potassium as to yield, upon the addition of persalts of iron, a copious precipitate of Prussian blue.\n\u201c The influence which salts in general exercise upon the secretion of urine is in the highest degree worthy of attention. It is a well known fact, that a very speedy emission of urine takes place in healthy individuals after drinking fresh pump-water. If ten glasses of water of from six to eight ounces each, containing no more than\tof its\namount in salts, be drunk at short intervals, an emission of urine of the usual colour will, after the lapse of about ten minutes, follow the second glass, and from eight to nine evacuations of urine will generally occur in the course of an hour and a half. The urine in this experiment emitted in the last evacuation will be clear and colourless like pump-water, and the amount of salts it contains is little more than is contained in pump-water. There are individuals who are capable of thus imbibing from six to eight quarts of water consecutively without any inconvenience !J","page":1273},{"file":"p1274.txt","language":"en","ocr_en":"1274\nURINE.\n\u201c But the case is quite different with water possessing an amount of salts equal to that of the blood; if even as little as 1-100th part of common salt be added to pump-water, and from three to four glasses drank, no evacuation of urine will take place, even two hours after drinking. It is almost impossible to drink more than three glasses of this saline water, for it weighs heavily on the stomach, as if the absorbent vessels had no power of taking it up. This obviously arises from the fluid within the channels of circulation, i. e. the blood, and the fluid without these vessels, i.e. the saline water, not exercising any physical action upon one another, i. e. not intermixing by endosmose or exosmose.\n\u201cWater containing a larger amount o. salts than the blood, such as common seawater, for instance, and even the weaker kinds of saline mineral waters, exercise again a different action from that of pump-water mixed with 1-100th of common salt ; not only no emission of urine takes place after the imbibition of such saline water, but water exudes from the circulating vessels into the intestinal tube, and, together with the saline solution, is carried off through the rectum ; purgation takes place, attended with much thirst, if the saline solution be in some measure concentrated.\n\u201c Considering that a certain amount of salts is absolutely necessary to constitute normal blood, we may deduce from these observations and experiments (which any one may easily imitate and verify upon his own person) that the physical condition of the tissues or of the bloodvessels opposes an obstacle to any increase or decrease of the amount of salts in the blood ; and thus that the blood cannot become richer or poorer in salts beyond a certain limit.\n\u201c Fluids containing a larger amount of salts than the blood remain unabsorbed, and leave the organism through the rectum ; fluids containing a smaller amount of salts than the blood enter into the circulation, absorb, and remove from the organism, through the urinary channels, all the soluble salts and other substances which do not belong to the constitution of the blood ; so that, finally, only those substances remain in the organism which exist in chemical combination with the constituents of the blood, and which, therefore, are incapable of being excreted by the healthy kidneys.\n\u201c 1 have convinced myself, by careful and minute examinations, that urine emitted after drinking a copious amount of water invariably contains a somewhat larger amount of salts than the water which has been drank ; whilst the amount of phosphates contained in the last emitted portions of the urine is extremely minute, and no longer detectable by the ordinary tests. It is, therefore, obvious that all the salts, without exception, contained in the urine, are to be considered as accidental constituents of the blood, which are excreted and removed from the organism precisely because they no longer form part of the normal consti-\ntution of the blood. The phosphates emitted with the urine were, previously, constituent substances which have been decomposed in the vital processes, or they existed as constituents of the blood, but upon its transformation into living tissues they were not admitted into their composition, they were not required in the constitution of the latter.\n\u201c Now, among the products of the vital processes, which, together with the soluble phosphates, are removed from the organism through the urinary organs and channels, there are two organic acids, namely, uric acid and hippuric acid, both possessing the property of combining with the soda or potass of the alkaline phosphates, and acquiring in the combination a higher degree of solubility than they possess, per se, at the common temperature of the body. It is obvious that, by the accession of these two acids, and by their action upon the phosphates of soda, an urate and hippurate of soda must be formed on the one hand, and an acid phosphate of soda on the other ; and that, consequently, the urine must acquire an acid reaction.\n\u201c But the presence of these two acids in the urine is not the only cause of its acid nature ; there exists another cause, which tends powerfully to maintain and increase it.\n\u201c According to the preceding remarks we ought to find in the urine all the soluble salts of the food, as well as a small amount of the phosphate of lime, which is soluble to a certain extent in acid fluids, together with magnesia. The amount of these latter substances will be in proportion to their solubility in acid phosphate of soda. The other insoluble salts of the aliments we ought to find in the f\u00e6ces. In other words, assuming that the materials composing the aliments become converted into oxygen compounds, that is, are burnt in the organism, we ought to find in the urine all the soluble salts of their ashes, and in the f\u00e6ces all the insoluble salts. Now, upon comparing the constitution of the ashes of the blood or of the aliments, or, rather, the salts contained therein, with those contained in the urine, we find that there exists a striking difference between their respective amounts of sulphates.\n\u201c According to the analyses of the ashes of the grains of wheat and rye*, the urine of an individual feeding exclusively upon bread ought not to contain a single trace of a sulphate, whilst the urine of an animal fed upon peas or beans ought to contain sulphates together with phosphates, in the proportion of nine of the former to sixty of the latter. Finally, as flesh contains no soluble alkaline sulphate (broth does not yield any precipitate of sulphate of barytes when tested with salts of barytes), the urine of carnivorous animals ought to be equally free from soluble sulphates. We find, on the contrary, that the urine of man, according to the most correct analyses, contains a far larger proportion of sulphates than the aliments partaken of ; nay, even that the amount of the sulphuric acid\n* Ann. der Chemie, Bd. xlvi. S. 79.","page":1274},{"file":"p1275.txt","language":"en","ocr_en":"URINE.\t1275\nreceived into the system must, in many cases, be equal or superior to that of the phosphoric acid contained in the aliments. According to the analysis of human urine made by Berzelius and Lehmann, the amount of the sulphates present in urine is nearly double that of all the soluble phosphates together. Hie-ronymi found the amount of sulphate of potass contained in the urine of the tiger, the lion, and the leopard, compared with that of the phosphates, to be as 1 to 7J. It can be distinctly and positively proved that these salts have not been partaken of in such proportions. But we now know the origin of the greatest portion of the sulphuric acid contained in the urine; this acid has entered the organism with the food, not in the form of a sulphate, but as sulphur.\n\u201c Gluten#, vegetable casein, flesh, albumen, fibrin, and the cartilages and bones, contain sulphur in a form quite different from the oxygen compounds of this substance. This sulphur is separated as sulphuretted hydrogen during the putrefaction of these substances ; it combines with the alkalies, operating upon these animal substances, and may be obtained from such combinations in the form of sulphuretted hydrogen by means of stronger acids.\n\u201c Now, we know from the experiments of Wohler, that the soluble sulphurets become oxidised in the organism ; and that thus, for instance, sulphuret of potassium becomes converted into sulphate of potass ; and it is therefore unquestionable that the sulphur of the constituents of the blood, derived from the aliments, or, what comes to the same point, the sulphur of the transformed tissues becomes finally converted into sulphuric acid by the oxygen absorbed in the process of respiration, and thus that in the urine it must appear in the form of sulphates ; and from this cause the original amount of these salts contained in the aliments becomes increased. The alkaline base which we find in the urine, in combination with this sulphuric acid, is supplied by the soluble alkaline phosphates ; and the latter, in consequence of the loss of part of this base, are converted into acid salts.\n\u201c By these considerations and views respecting the cause of the acid reaction of urine, I have been induced to prepare an artificial urine, which possesses the properties of natural urine, even although sulphuric^ acid be altogether excluded.\n\u201c If 40 grains of dry phosphate of soda (or 90 grains of the crystallised salt, P Os 2\nq -f- 24 Aq.) be dissolved in one pound\nof water, a fluid will be obtained having an alkaline reaction ; if to this fluid we add 15 grains of uric acid, and 15 grains of hippuric acid, and the mixture is heated, both acids\n* Dietrich (in the laboratory of Giessen) has examined gluten with regard to its amount of sulphur ; he found wheat-gluten to contain from 0-038 per cent, to 0-035 per cent, of sulphur, exactly the same proportion as is contained in albumen of fibrin.\nwill completely dissolve, imparting a strong acid reaction to the fluid. The solution thus prepared does not deposit a trace of uric acid at a temperature from 37\u00b0 to 38\u00b0 (= 98\u00b0, 100\u00b0 Fahrenheit = the heat of the blood) ; nay, it is even only several hours after complete refrigeration that a sediment is formed, consisting of uric acid containing soda : this sediment is of an analogous form to that deposited by natural urine after standing at rest for a long time. Upon collecting this sediment, in one of my experiments, after the lapse of twenty-four hours, I found that it weighed 7| grains, so that there remained still in solution 22-t grains of the organic acids. Dilute mineral acids produce immediately, in the fluids filtered off from the sediment, a precipitate of uric acid.\n\u201c Proust, Prout, and all the other chemists who examined the urine previous to, or about the same period as, Berzelius, ascribed its acid reaction to the uric acid or phosphoric acid; hippuric acid was not known as a constant attendant upon uric acid.\n\u201c It follows, from all we have hitherto stated, that the acid nature of the urine of carnivorous animals, as well as that of man, depends upon the nature of the bases partaken of in the aliments, and upon the particular form of their combinations. In the flesh, blood, and other parts of animals, as well as in the grains of the cereal and leguminous plants, there exists no free alkali. The alkali which these substances contain is invariably combined with phosphoric acid ; the acids formed in the organism by the vital process, namely, sulphuric acid, hippuric acid, and uric acid, share the alkali amongst them ; and this, of course, must give rise to the liberation of a certain amount of phosphoric acid, or, what comes to the same point, to the formation of a certain amount of acid phosphates of soda, lime, and magnesia. The proportional amount of the liberated phosphoric acid varies with the temperature ; at a higher temperature the phosphate of soda dissolves a larger amount of uric acid and hippuric acid than at a lower temperature \u2014 at from 37\u00b0 to 38\u00b0 more than at 15\u00b0. It is owing to this that urine, upon refrigeration, sometimes deposits uric acid, or urate of soda in a crystalline state, which, of course, can only take place by the uric acid, at a lower temperature, restoring to the phosphoric acid the soda or potass which, at a higher temperature, it had withdrawn from it. At the common temperature phosphoric acid decomposes urate of soda, whilst, at a higher temperature, uric acid decomposes phosphate of soda. When urine, containing uric acid, and manifesting an acid reaction, forms no sediment upon cooling, it shows that the amount of the phosphoric acid and that of the uric acid exactly balance each other with regard to their affinity for soda. Had there been present a larger proportion of uric acid, this would have separated upon cooling ; whilst, on the other hand, the presence of a preponderating proportion of phosphoric acid would","page":1275},{"file":"p1276.txt","language":"en","ocr_en":"URINE.\n1276\nlikewise have caused the precipitation of uric acid, because the affinity of the former for soda would then exceed that of the latter. This explains the circumstance that urine, in certain states, when from some cause or other its amount of sulphuric, hippuric, or other acid, becomes increased, precipitates a larger proportion of uric acid than urine in its normal state. The solubility of uric acid in urine must decrease in proportion as the amount of the other acids present in the urine increases, because those acids share the soda with the uric acid ; and, of course, the larger the amount of soda which combines with these other acids, the less comes to the share of the uric acid. It is likewise owing to this, that uric acid very frequently precipitates from urine upon the addition of mineral or other acids, and that urine of a turbid, whey-like appearance, from the presence of uric acid, frequently manifests a far more strongly acid reaction than normal urine.\n\u201c Now, bearing in mind that the use of alkaline citrate (Gilbert Blane), of neutral paratartrate of potass, bi-tartrate of potass, tartarised soda, acetates of potass and soda, and tartarised borax, renders the urine alkaline by creating in it an amount of carbonated alkali ; and that, likewise, after the eating of fruit, such as cherries, strawberries, \"&c., the urine is of an alkaline nature, inasmuch as these fruits contain alkalies combined with vegetable acids, it is obvious that the acid reaction of healthy urine is purely accidental, and that urine of an alkaline or neutral reaction cannot be considered as a symptom of a diseased condition of the body. All vegetable aliments, without exception, \u2014 tubers, roots and leaves, potatoes, turnips, greens, &c.,\u2014 contain alkalies in combination with vegetable acids ; potatoes, for instance, contain alkaline citrates ; turnips, alkaline racemates and oxalates, &c. All these plants yield, upon incineration, more or less strongly alkaline ashes, the bases of which were contained in the living plants, as salts of vegetable acids.\n\u00ab It is obvious that by adding these vegetables to a meat diet, to\u2018bread and to other aliments prepared from flour, the nature of the urine must become thoroughly altered ; for the alkalies which these vegetables contain in combination with vegetable acids, enter the urine in the form of carbonated alkalies, and neutralise the acids, of whatever kind, which may be present. When partaken of in a certain proportion, they render the urine neutral ; when partaken of in a larger proportion, they impart to it an alkaline reaction.\n\u201c The urine of all animals feeding upon vegetables, such as grass, herbs, roots, &c., has an alkaline reaction. The urine of the horse, of the cow, of the sheep, of the camel, of the rabbit, of the guinea-pig, of the ass, &c. is alkaline ; it contains alkaline carbonates, and acids produce in it a lively effervescence.\n\u00ab The acid, neutral, or alkaline reaction of the urine of healthy individuals does not depend upon any difference in the processes of digestion, respiration, or secretion, in the various\nclasses of animals, but upon the constitution of the aliments, and upon the alkaline bases which enter the organism through the medium of these aliments. If the amount of these bases is sufficiently large to neutralise the acids formed in the organism, or supplied by the aliments, the urine is neutral , whilst it manifests an alkaline reaction when the amount of alkaline bases thus supplied to the organism is more than sufficient to neutralise the acids; but in all these cases the urine accords with the nature of the aliments taken.\n\u201c The inorganic bases and acids contained in the urine were, with the exception of sulphuric acid, which joins them in the organism, constituents of the aliments. The amount of inorganic bases and acids emitted through the urine in twenty-four hours must, in adult individuals, be equal to that of these bases and acids supplied to the organism, during the same period, through the medium of the aliments.\n\u201cFrom these data it follows necessarily, first, that the analysis of urine when made without respect to the inorganic salts, acids, and bases, supplied by the aliments, teaches nothing whatever, and by no means justifies us in drawing therefrom any physiological or pathological inference ; secondly, that from the nature of the ashes of the aliments we are able to determine, positively, the constituents of the urine emitted ; and thirdly, that only when these latter have been distinctly ascertained, can we expect to derive, from the analysis of the urine, any correct information with respect to the inorganic matters which have come to be present in it through processes of disease ; this, at least, is the chemical method of quantitative investigation.\n\u201cBearing in mind that the urine contains the soluble constituents of the ashes of the aliments, whilst the faeces contain the insoluble part of these constituents, we may form an accurate knowledge of both, at once determine in which urine soluble alkaline phosphates must be present, and in which they cannot exist. The ashes of all seeds, and of flesh and blood, contain a certain amount of soluble and insoluble phosphates, whilst the ashes of vegetables contain no free alkaline phosphate, but only insoluble phosphates. These vegetable ashes contain far more lime and magnesia than is required for the neutralisation of the phosphoric acid present. Hence, upon incinerating a plant, together with its seed, and lixiviating the ashes, we find no alkaline phosphate in the fluid obtained, although the lixivium of the ashes of the seeds, when incinerated and lixiviated by themselves, yields a considerable amount of these phosphates : the excess of lime and magnesia contained in the leaves and the straw enter here into combination with the phosphoric acid of the soluble alkaline phosphates, forming an insoluble compound.\n\u201c It will now be understood why the alkaline phosphates are generally absent from the urine of herbivorous animals, and also why,","page":1276},{"file":"p1277.txt","language":"en","ocr_en":"URINE.\n1277\nin certain cases, they may be found in the urine of these animals. If the nutriment of these animals contains no soluble phosphates, their urine cannot contain any ; whilst, if we add a certain proportion of grain to their food, the alkaline phosphates may be detected in their urine. Thus it is obvious, likewise, that the soluble phosphates in the urine of man are merely accidental constituents, and that by simply adding lime or magnesia to the aliments, and thus assimilating the constitution of these aliments to that of the food of herbivorous animals, the urine must become altered in its nature and properties. The knowledge of the influence which alkalies, magnesia, and lime, or acids, exercise upon the properties of the urine, or, in other words, upon the secretory process of the kidneys, in the healthy organism, is of the highest importance for the curing of diseases.\n\u201c I believe that there is now required only a small number of good and correct observations to establish a fixed rule for the remedies necessary in various cases. Future properly-directed experiments will prove whether sanguification is absolutely dependent upon the presence of alkaline phosphates or not ; we shall be able to determine whether weak solutions of alkaline phosphates are not the best solvents for uric acid deposited in the bladder ; and likewise what is the influence which aliments rich in sulphur, such as mustard, for instance, exercise upon the separation of uric acid in the bladder, in consequence of the formation of sulphuric acid. At any rate, we may, by a judiciously-selected diet, alter with positive certainty, and at pleasure, the nature of the urine ; we may, without causing any injury to health, keep it alkaline for a long time, by adopting a vegetable diet ; and this is certainly the first condition necessary to insure the entire prevention of the formation of uric acid, as is the case with the herbivorous animals. By its combination with an alkaline base, uric acid must in the organism resolve itself into its ultimate oxygen compounds with the same facility as other organic acids, if the physician prohibits all substances to be taken as food which, like wine or fat, take possession of the oxygen necessary for the transformation of uric acid into carbonic acid and urea.\n\u201c The carbonated alkali in the urine of herbivorous animals is separated from the blood by the kidneys ; the urine derives it from the blood ; it is certain, therefore, if we examine the blood one hour or a few hours after the animal has partaken of food, we must find in it this alkali in the same state as it is found in the urine, and that at other periods of the day the ashes of the blood may not contain the least trace of free alkali. But the free alkali does not co-operate in the vital process in the animal organism ; or, if it is necessary in this process, the part which it has to perform may be undertaken with the very same effect by the bibasic and tribasic alkaline phosphates.\n\u201c In like manner, when we are contemplating the presence of hydrochloric acid in the gastric juice, we must remember that the alkaline bases, soda, potass, lime, magnesia, are present in the aliments whilst in their natural state, invariably in the form of salts ; that is, in combination with phosphoric acid, or with organic acids. When, therefore, in the digestive process, hydrochloric acid is supplied by the gastric juice, the first action of this acid is confined to the decomposition of these salts ; the hydrochloric acid withdraws lime from the phosphate of lime ; potass, or soda, chloride of calcium, or chloride of sodium or potassium, is formed on the one hand, and acid phosphate of soda or potass, or acid phosphate of lime, on the other ; or acetic acid, paratartaric acid, or citric acid, are liberated by the decomposition of the salts of these vegetable acids contained in the aliments. At a certain stage of digestion the chyme will, according to the nature of the food partaken of, contain acid phosphates or free vegetable acids ; and it is only upon the supply of gastric juice continuing, that thus, upon the amount of the hydrochloric acid increasing, we may detect, by analysis, free hydrochloric acid in the chyme : the gastric juice taken from an empty stomach contains invariably free hydrochloric acid, or acid phosphates.\u201d\nLehmann has made some very interesting observations, published in the \u201c Journal f\u00fcr Praktische Chemie,\u201d by which he has shown the effects of diet on his own urine. He first observed the results produced by his ordinary diet during thirteen days, and found that the urea amounted on an average to about 46 per cent, of the whole of the solid matter excreted. The average quantity of urea excreted during the 24 hours amounted to about 500 grains.\nDuring six days, on an ordinary diet, the uric acid excreted averaged about 1089 parts per 1000, and the amount excreted during the 24 hours was about 18 grains.\nOn a purely animal diet, Lehmann found the amount of solid matters discharged in the urine during the 24 hours was much increased. The urine became pale in colour and strongly acid. On the addition of nitric acid, crystals of nitrate of urea were immediately formed, and uric acid was deposited in large crystals.\nBy careful analysis, however, Lehmann determined, that though a purely animal diet increases the proportion of urea excreted during the 24 hours, the amount of uric acid is not by any means materially influenced^\nThe earthy phosphates were discharged in large quantities under a purely animal diet, rising to about three and a quarter times as much as when ordinary mixed diet was taken.\nWith respect to the effects of a vegetable diet, Lehmann observed the urine to become of a darker colour than natural, and to remain of an acid reaction much longer than ordinary human urine. The following tables of comparison have been constructed by Franz Simon from the results of Lehmann : they possess a high physiological value.","page":1277},{"file":"p1278.txt","language":"en","ocr_en":"1278\nURINE.\n\t\tOn\tOn\tOn\n\t\tmixed\tanimal\tvegetable\n\t\tDiet.\tFood.\tFood.\nAmount\tof'\t\tgrammes.*\tgrammes.\tgrammes.\nurine in 24 hours -\t- J\t\\\t1057-8\t1202-5\t909*\nSpecific gravity Solid residue ]\tI\t1022-\t1027-1\t1027*5\nfrom\t1000 parts of urine J\t\\\t65-82\t75-48\t66-41\nSolid\tmatter 1\tI\t\t\t\npassed in 24 hours -\t- J\t[\t67-82\t87-44\t59-23\nUrea during a mixed diet Urea during an ani-l mal diet\t-\t- J\nUrea during a vege- 1 table diet\t-\t- J\nIn 100 Parts\tDaily\nof solid\tAmount in\nResidue.\tGrammes.\n46-230\t32-498\n61-297\t53-198\n39-086\t22-481\nUric acid during a 1 mixed diet -\t- J\nUric acid during an' animal diet -Uric acid during vegetable diet\nan\nIn 100 Parts of solid Residue.\tDaily Amount in Grammes.\n1-710\t1-183\n1*674\t1-478\n1-737\t1-021\nFrom the above it would appear, that the amount of urea is always diminished by a vegetable diet, while the proportion of uric acid excreted is not materially affected. Lehmann ascertained also, by other experiments, that the amount of lactic acid, phosphates, and lactates was scarcely changed, whether the subject of experiment lived on an animal, or vegetable, or a mixed diet. A vegetable diet was found to increase considerably the daily discharge of extractive matters ; while far less was passed under an animal diet than when either a mixed or vegetable dietjwas used.\nThe following table, containing the results of Lehmann on different forms of diet, as affecting the daily amount of the various solid matters discharged by the urine, is a very important addition to our knowledge of this subject : \u2014\n\t<u\ta;\t<D\t\u00d4.2\n*\t5 \u2022n\ts 'cS a\tegetabl Diet.\t\u00a3Q ? p \u00a7g\n\ts\t<\t>\t** to\n\tgramm.\tgramm.\tgramm.\tgramm.\nSolid constituents\t67*82\t87-44\t59-24\t41-68\nUrea\t32*50\t53-20\t22*48\t15*41\nUric acid\t1*18\t1*48\t1-02\t0 73\nLactic acid and\")\t2-72\t2-17\t2-68\t5-82\nlactates\t-J Extractive mat-1\t10-49\t5-20\t16-50\t11-85\nters -\t-J\t\t\t\t\n* The gramme is equal to 15-4 grains troy. -\nSevere and continued bodily exercise was found by Lehmann to increase the discharge of urea, lactic acid, phosphates, and sulphates. He observed a diminution, however, in the proportion of uric acid and extractives discharged under the same conditions.\nSimon, simultaneously with Lehmann, ascertained that the amount of urea, sulphates, and phosphates excreted, is increased by strong bodily exercise. Simon remarks upon this result:\u2014\u201cFurther confirmation of the above observation is certainly desirable. If, however, we might assume it as a general fact, it would be an additional argument in favour of my view regarding the formation of urea ; for it would then become still clearer that the urea is not formed during the change which occurs in the blood as a consequence of peripheral nutrition, but that it is formed during those processes which are dependent on the respiratory and circulatory functions, in which we must seek for the greater part of the carbonic acid which is exhaled, and for the principal source of animal heat. I refer to the active metamorphosis of the blood, or to the mutual action excited by the blood corpuscles, the plasma, and the oxygen held in solution in the blood, on each other.\u201d\nDr. Percy has made experiments corroborative of the views of Simon. He did not, however, observe any augmentation of the soluble salts, viz. phosphates, sulphates, and chlorides.\nIn relation to this subject, Simon alludes to the opinion expressed by Berzelius, that at least a portion of the sulphates and phosphates occurring in the urine, are derived from the oxidation of phosphorus and sulphur which previously existed as components of protein compounds, which become changed during the metamorphosis of the blood. This view I hold to be especially true as respects the phosphates, and would here refer the reader to a paper of mine printed in the Philosophical Magazine*, in which I showed that the amount of alkaline phosphate contained in the serum of arterial blood is much greater than in that of venous, and that the amount of such salt in venous serum can be at once increased by exposing the blood corpuscles to air, and consequently to the action of oxygen during the coagulation of the fluid.\nI feel satisfied, indeed, from my results, that one great and essential difference between arterial and venous blood consists in the great excess of alkaline phosphate contained in the serum of the blood of the arteries as compared with that of the veins.\nWith respect to the quantity of chloride of sodium excreted by the urine, it is subject to great variation. Simon remarks, that the urine in disease is sometimes deficient in salts, and that this deficiency takes place at the expense of the chloride of sodium. He found but a trace of chloride of sodium in the urine of a patient suffering from typhus.\nDr. Bence Jones has made experiments on\n* On a Function of the Red Corpuscles of the Blood, by G. Owen Rees.","page":1278},{"file":"p1279.txt","language":"en","ocr_en":"URINE.\n1279\nthe variation of the sulphates in urine, and has arrived at the following conclusions : \u2014\n1.\tThe sulphates are increased by food, both animal and vegetable.\n2.\tExercise does not produce so marked an increase in the sulphates.\n3.\tSulphuric acid in large doses increases the proportion of sulphates ; in small doses it produces little or no effect.\n4.\tSulphur, when taken, increases the sulphates in the urine, and sulphate of soda or magnesia produces the greatest effect on the quantity of sulphates in the urine.\nWith respect to the phosphates contained in the urine, Dr. Jones has arrived at the conclusion, that the quantity of earthy phosphates depends on the quantity contained in the ingesta, and that this is also the case with the alkaline phosphates. These latter, however, are to a certain extent increased by exercise.\nURINE OF ANIMALS.\nThe urine of animals varies much in character, according to the kind of food taken. Thus, there are striking differences between the urine of the carnivora and the herbivora. The urine of carnivorous animals is generali)7 acid when discharged, but becomes alkaline and ammoniacal very rapidly. The urine of herbivorous animals, on the contrary, is alkaline when passed, and contains a large proportion of alkaline and earthy carbonates. Simon, however, states the urine of horses immediately after it is passed, to be occasionally acid. The urine of the carnivora, according to the observations of Vanquelin and H\u00fcnefeld, contains neither the uric nor hippuric acids. Hieronymi, however, who examined the urine of the lion, the tiger, and the leopard, detected uric acid in small proportions. The urine of the herbivora contains hippuric acid in large quantities, in the form of hippurate of soda. No uric acid is present according to the analyses of most chemists, but traces of it have occasionally been found in the urine of the graminivora.\nHieronymi obtained the following result by the analysis of the mixed urines of the lion, tiger, and leopard. This may, therefore, be regarded as the type of the urine of the carnivora : \u2014\nWater........................ 846-00\nUrea, alcoholic extractive and free\nlactic acid -\t132-20\nUric acid -\t0*22\nVesical mucus - - - -5-10 Sulphate of potassa - - - 1\u201822 Chloride of ammonium, and traces\nof chloride of sodium \u25a0\u25a0\t- 1*16\nEarthy phosphates\t-\t1-76\nPhosphates of soda\tand potassa 8-02\nPhosphate of ammonia -\t- P02\nLactate of potassa\t-\t3-30\nThe specific gravity of the urine of these large carnivorous animals varies, according to Hieronymi, from 1059 to 1076. It is clear when passed, and of a bright yellow colour.\nThe urine of the herbivora is turbid when passed, and generally possesses a lower specific gravity than that of carnivorous animals. Thus, the urine of horses, according to Simon, is about 1045. That of oxen, according to Von Bibra, varies from 1040 to 1032.\nThe following are two analyses of the urine of horses by Von Bibra : \u2014\nWater\t-\t885-09\t912*84\nUrea -\t-\t-\t-\t12-44\t8-36\nHippuric acid\t12-60\t1 23\nWatery extractive\t21-32\t19-25\nAlcoholic extractive\t25-50\t18-26\nMucus\t-\t0-05\t0-06\nSalts soluble in water -Salts insoluble in water\t23-401 18-80 J\t|- 40-00\nWith respect to the hippuric acid present, Von Bibra found that it varied extremely in proportion in different specimens of urine. He never found that it became replaced by the benzoic acid when horses were exposed to excessive labour, an Opinion which has been very generally received by chemists. He never, indeed, could detect benzoic acid under any circumstances, except in such small quantities as to require the assistance of the microscope to show its presence.\nThe deposit which causes the turbidity observed in the urine of the horse, is composed as follows, according to Von Bibra : \u2014 Carbonate of lime -\t80*9\nCarbonate of magnesia -\t-\t12-1\nOrganic matter -\t-\t-\t-\t7 0\nThe horses that supplied the above described specimens of urine, were fed on hay and oats, and used in agriculture.\nBoussingault examined the urine of a horse fed on trefoil and vetches, and states its composition as follows : \u2014\nWater -Urea -\nHippurate of potassa Lactate of potassa -Lactate of soda Bicarbonate of potassa Carbonate of lime Carbonate of magnesia Sulphate of potassa -Chloride of sodium -Silica -\nPhosphates, \u2014 none present.\n-\t910-76\n-\t3P00\n-\t4-74\n-\t11-28 - 8-81\n-\t15-50\n-\t10-82\n-\t4-16 1-18\n-\t0-74\n-\troi\nChemists have described a red oil as existing in the urine of herbivorous animals, and have attributed the peculiar odour of the secretion to the presence of that substance.\nBoussingault carefully examined the urine of horses with a view to obtain this oil for examination, but failed to extract it, though he operated on twenty-six gallons. He distilled the whole quantity, but no trace of oil came over into the receiver. All that he obtained was a colourless fluid, strongly impregnated with the odour of horse\u2019s urine.\nHe considers this odour dependent upon the presence of a volatile acid, and believes that the volatile red oil obtained by chemists results from the decomposition of the alkaline","page":1279},{"file":"p1280.txt","language":"en","ocr_en":"1280\nURINE.\nhippurates, and that it is not produced until the urine is evaporated to dryness.\nThe following are two analyses, by Von Bibra, of the urine of oxen obtained at different times. The animals had been fed on clover and\nhay : \u2014\nWater\t-\t912*01\t923*11\nUrea\t-\t1976\t10*21\nHippuric acid -\t-\t5*55\t12*00\nMucus\t0*07\t0*06\nAlcoholic extract\t-\t14*21\t10*20\nWatery extract -\t-\t22*48\t16*43\nSoluble salts\t-\t24*42\t25-77\nInsoluble salts -\t1*50\t2*22\nIt will be perceived that the insoluble salts or earthy carbonates are in small proportion in the urine of oxen, while in the urine of horses they are present in about equal proportion to the alkaline carbonates. The urine of a cow, which was submitted to analysis by Boussingault, gave a result varying considerably from that obtained*by Von Bibra from the urine of oxen, as above quoted. It\nyielded in 1000 parts : \u2014\nWater.........................921*32\nUrea -----\t18*48\nHippurate of potassa\t-\t-\t16*51\nLactate of potassa -\t-\t-\t17*16\nBicarbonate of potassa -\t-\t16*12\nCarbonate of magnesia -\t-\t4*74\nCarbonate of lime -\t-\t-\t0*55\nSulphate of potassa\t-\t-\t3 60\nChloride of sodium\t-\t-\t1'52\nSilica, a trace.\nPhosphoric acid, none.\nThe great excess of the earthy salts observed in the urine of horses, as compared with that of oxen, is a remarkable circumstance, and would appear to be in some way connected with the difference in conformation of the two animals rather than on differences in diet. Thus the conditions alluded to pertained whether the horses were fed on hay and oats, or on trefoil and vetches. The oxen too, the urine of which was examined by Von Bibra, were fed on hay and clover, a diet closely resembling that of the horses ; but the earthy salts were, notwithstanding, found in the urine in very small proportion.\nVoo-el has examined the urine of the ele-phant and the rhinoceros. That of the elephant possessed the following characters :\n1.\tIt was turbid, owing to carbonates of lime and magnesia.\n2.\tIt contained more urea than the urine of the rhinoceros.\n3.\tNo hippuric acid was present*\nThe urine of the rhinoceros is described\nas follows:\u2014\t.\t,\t\u201e\n1\tIt was turbid, owing to the presence of carbonate of lime, earthy phosphates, silica and peroxide of iron.\n2\tIt gEivc out the odour of formic ucid.\n3! It yielded hippuric acid in considerable quantity.\n* Brandes believed be detected the hippuric acid in this urine in combination with urea and an alkali.\nChevreul examined the urine of the camel.\n1.\tIt contained no uric acid.\n2.\tUrea was present in abundance.\n3.\tNo phosphates could be detected.\n4.\tThe chief constituents, in addition to urea, were chloride of sodium, hippurate of soda, carbonate of soda, sulphate of potassa, carbonate of ammonia, and traces of sulphate of soda and oxide of iron.\nChevreul considers this urine to contain a volatile oil to which it owes its colour, and to which he ascribes the property it possesses of becoming red on the addition of the mineral acids.\nThe urine of pigs has been examined by Lassaigne, Van Setten, and Boussingault. Its specific gravity appears to vary between 1003 and 1013.\nVan Setten\u2019s analysis is as follows : \u2014\t\nWater -\t-\t-\t-\t-\t990*028\nUrea -\t-\t-\t-\t-\t0*750\nUric acid -\t0*195\nWatery extractive\t1*708\nAlcoholic extractive\t1-105\nResinous matter -\t0-425\nAlbumen and mucus\t0*721\nLactic acid -\t-\t-\t-\t0*490\nStearin\t-\t-\t-\t-\t0-092\nSugar\t-\t0-375\nPhosphate of soda\t1*376\nSulphate of potassa, chlorides\t\nof potassium and sodium -\t2*075\nSulphates of lime and magnesia\t0*425\nSulphate of ammonia\t0*196\nChloride of ammonium -\t0*010\nVon Bibra describes the urine\tof the pig\nas clear, odourless, and of alkaline re-action. He could not detect uric, hippuric, or benzoic acid in it when operating on three ounces of the fluid; but he subsequently obtained microscopic crystals of hippuric acid. No trace of uric acid could be discovered.\nBoussingault could not detect hippuric acid in the urine of a pig fed on potatoes and salt. He varied the diet by the addition of green trefoil, but still he could not discover the acid.\nVon Bibra analysed the urine of the goat. He found it alkaline and of pungent odour, of specific gravity 1008 or 1009. The animals had been kept in a stable and fed on bad hay. From two analyses made on 1000 parts, the following results were obtained : \u2014\nWater -\t980-07\t983*99\nUrea\t-\t-\t-\t3*78\t0-76\nHippuric acid -\t1*25\t0*88\nAlcoholic extractive -\t4*54\t4*66\nWatery extractive\t1*00\t0*56\nMucus -\t0-06\t0*05\nSoluble salts\t8*50\t8*70\nInsoluble salts -\t0-80\t0*40\nIn this urine, as in\tthat of\toxen, the\nalkaline carbonates greatly predominate over the earthy salts.\nAccording to Vanquelin, the urine of the beaver contains the colouring matter of the bark of the willow, which is the food of the","page":1280},{"file":"p1281.txt","language":"en","ocr_en":"URINE.\t1281\nanimal. He detected it by using alum as a mordant for pieces of cloth soaked in the urine. He detected the presence of bicarbonates of lime and magnesia, and hippurate of soda. He could not find any phosphates, nor uric acid.\nThe urine of rabbits and guinea-pigs has an alkaline reaction, and contains alkaline and earthy carbonates. It presents no peculiar qualities.\nYon Bibra analysed the urine of the hare, both in summer and in winter. In December he found the urine turbid and alkaline, depositing phosphate of magnesia. In June it was only faintly alkaline. The proportion of earthy phosphates present was more than twice as great in summer as in winter, which Simon remarks upon as probably caused by the great difference in the food of the hare during the two seasons. With respect to his examination of the urines of herbivora, Von Bibra states he obtained in most of them indications of the presence of humic acid, or a substance closely allied to it.\nAs regards these analyses, which are quoted from Simon\u2019s work on animal chemistry, it would appear a matter of regret that experiments have not been made on an extended scale on the same animal, under different conditions ; more especially under variations in food, temperature, and moisture. Such form of inquiry could not fail to be of eminent service to physiology, and much light might thus be thrown on the question of diet, in respect to constitution and predisposition to disease, a subject greatly needing elucidation, notwithstanding the labour and ingenious activity which has been devoted to it during the last few years.\nUrine of Birds, &c. \u2014 The urine of birds is excreted from the cloaca in the form of a thin paste, which hardens by exposure. Urate of ammonia is the principal constituent. The urine of carnivorous birds, however, contains urea in considerable quantity, which distinguishes it from that of birds feeding on vegetable substances. Chemists have also described a green colouring matter, as peculiar to the urine of carnivorous birds.\nThe constituents of the urine of the ostrich, according to Vanquelin and Fourcroy, are \u2014\nUric acid.\nSulphate of potassa.\nSulphate of lime.\nChloride of ammonia.\nOily matter.\nA peculiar animal matter.\nAcetic acid (?)\nThe urine of serpents is excreted in the form of a white, earthy mass. It is made up of uric acid, combined with potassa, soda, and ammonia. Phosphate of lime is also present.\nCass and Henry state that they obtained urea from the urine of serpents. That principle was sought for in vain, however, by Vanquelin and Fourcroy.\nSimon gives the following as the result of an analysis of the urine of a rattle-snake. He\nVOL. IV.\noperated on 100 parts, weighed, when quite dry.\nFree uric acid, some fat, and ex- \"I tractive matters\t-\t-\tJ\nUrate of ammonia\t-\t-\t-31*1\nUrate of soda, with some chloride \"1\tg.g\nof sodium -\t-\t-\tJ\nUrate of lime -\t-\t-\t-\t1*4?\nPhosphate of lime -\t-\t-\t1*3\nDr. J. Davey examined the urine of the bull-frog (rana taurina). He found it of specific gravity 1003. Urea, chloride of sodium, and a little phosphate of lime were also present.\nMarchand\u00e9 analysis of the urine of the land-tortoise (testudo tubulata) yielded the following result, \u2014\nWater\t-\t-\t-\t950-64\nUrea\t-\t-\t-\t-\t6-40\nUric acid\t-\t17-25\nSalts and indeterminate organic \\\t25-70\nmatter\t-\t-\t-\tj\t\nThere was no hippuric acid in this urine. It possessed a faintly acid reaction, and is stated to haye presented the appearance of pus. Ether extracted a brownish-coloured fat, having an urinous odour.*\nURINE IN DISEASE.\nWith respect to the urine of the human subject, it has been shown that considerable variation occurs in health according to the modifications which may have been made in diet. The urine of the lower animals is doubtless, to a certain extent, amenable to the same rule. We observe also striking differences in the urine of herbivora fed on similar diets, as has been noticed above in the case of the horse and the ox, both graminivorous animals and fed nearly alike for experiment, but whose urine showed, on analysis, very marked and important differences. This variation in the result of the digestive process would appear, in such case, to depend upon the internal arrangement of the chylopoietic organs, and should perhaps more especially be attributed to differences in the minute anatomy of the mucous secreting surfaces. Certain fixed variations, then, are to be observed in the constitution of the urine as results of difference in healthy anatomy ; and so in the same way, when certain organs are affected by disease, we find a set of changes occurring in the urine quite as marked in character ; and it is of especial moment to the physician that he should be able easily and accurately to appreciate them. While studying those conditions, it is however of the highest importance that the changes which diet, the temperature to which the body may have been exposed, the amount of moisture in the air, &c., should be considered, and that the physician should be able to separate in his mind those phenomena which are indicative\n* Quoted by Simon from Erdmann and Marchand\u00e9 Journal, 1845. iv. 4.\n4 N","page":1281},{"file":"p1282.txt","language":"en","ocr_en":"J 282\nURINE.\nof morbid change in important organs, from such as may merely be the results of actions occurring in perfect health, and consistent with its preservation.\nMany pathological conditions of the urine are indeed closely simulated by the unimportant changes to which I have alluded. Thus the urine of diabetes insipidus, often a most severe and unmanageable disease, can scarcely be distinguished from that occasionally secreted by healthy persons exposed to cold or moisture, or both, without sufficient exercise to maintain the full amount of cutaneous exhalation. Such a specimen, were it examined carelessly, or allowed to guide the judgment without due attention to concomitant circumstances and previous history, might lead (and I may say has led) to mistakes both injurious to the patient and vexatious to the practitioner.\nIn studying the pathology of the urine, it is also especially important that we should not give undue regard to chemistry, nor be led astray by theories and generalisations such as that fascinating science so constantly would tempt us to enter upon. It must be remembered that in most cases chemistry as yet only assists us in the detection of symptoms, and in the present state of our knowledge can only thus far serve us, but must fail as a guide to a true knowledge of diseased action or appropriate methods of treatment. This consideration, however, is far from depressing to those who regard the subject in a truly philosophical spirit; for be it remembered that when we have detected sugar or albumen in the urine, and when the modes of examination are rendered both easy and exact by chemical labour, we have reaped a most valuable advantage by becoming acquainted with a symptom, without which, we should have been left in such a position that we might have despaired of ever obtaining an insight into the pathology of two most important diseases. A knowledge of symptoms thus acquired by chemistry at once enables us to make use of a large amount of valuable information derived from experience, and to bring to our assistance remedies which would not otherwise have suggested themselves, or perhaps have been considered inapplicable. It has unfortunately too often been attempted to push chemical reasoning to the uttermost in considering urinary diseases ; and there is a class of persons, greatly increasing in the present day, who have thus inflicted much mischief on a science which requires great labour in its prosecution, and consequently is the more eagerly condemned as useless by the idle or ungifted practitioner. If we confine the application of chemistry, in urinary disease, merely to symptomatology, it is easy to show that we are deeply indebted to the science, and it is the especial duty of those who are most conversant with it to regard its further application with great jealousy.\nI shall now proceed to describe the urine as it appears in various diseased conditions of the body, beginning with those variations\nfrom healthy constitution characterised by the existence of deposits of various kinds known as urinary deposits. It is not, however, within the province of this article to enter upon any pathological considerations relating to these abnormal conditions.\nLithic acid Deposit.\nThis deposit (commonly known as \u201cred sand\u201d or gravel) occurs in urine in many forms, the crystals as seen under the microscope presenting the appearances figured below (>g. 791).\nFig. 791.\nUrine depositing lithic acid is generally of a deep yellow colour, and acid beyond the normal degree. Its specific gravity is mostly somewhat above that of health. Lithic acid occasionally deposits from urine in an amorphous concrete form, and is seen in rounded or flattened masses adhering to the bottom of the chamber vessel. This latter kind of deposit is the most dangerous as respects the formation of calculi.\nDeposit of Lithates.\nThis form of deposit, known as the lateri-tious deposit, from ts resemblance to brick dust, consists of lithic acid combined with ammonia, and in some few cases with lime, magnesia, or soda. The microscopic appearances shown by the lithates are as under 0%. 792).\nFig. 792.\nThe spheroidal masses with projecting needle points (b), I believe to indicate lithate of lime, while the masses having projecting crystals with truncated ends (c), 1 believe consist chiefly of lithate of magnesia. The lithate of ammonia is amorphous, sometimes spheroidal with adhering spicula, or is seen making up a dotted background (a). Urine depositing the lithates is generally of a higher specific gravity than natural, and is passed clear. After the deposit has occurred, the application of a gentle heat is always sufficient to re-dissolve it.","page":1282},{"file":"p1283.txt","language":"en","ocr_en":"URINE.\n1283\nDeposit of Earthy Phosphates.\nThe earthy phosphates, consisting of magnesia in combination with ammonia and phosphoric acid, are seen as deposits in the urine in two forms, viz. as a monobasic and a bi-basic salt. The monobasic phosphate, which is seen in neutral or only slightly alkaline urine, presents the microscopic appearances as under (fig. 793).\nFig. 793.\nThe bibasic salt, which is observed in highly ammoniacal urine, gives the following figures (fig. 794).\nFig. 794.\nUrine depositing the first of these two varieties of sediment is generally of lighter colour than natural, and of moderately high specific gravity.\nThe second variety, if not occasioned by the use of alkaline remedies, generally indicates important mischief in some part of the urinary apparatus, and is often combined with large quantities of epithelium, mucus, pus, and blood corpuscles.\nDeposit of Oxalate of Lime.\nThis deposit, which is composed of lime in combination with an acid foreign to the constitution of healthy urine, presents itself under the microscope in the following forms, first described by Dr. Golding Bird (fig. 795).\nFig. 795.\nThe appearance of dark crystals, looking like cubes, is observed when this deposit is allowed to dry. The transparent spot in the centre is caused by reflection from the sides of the octohedron.\nUrine depositing oxalate of lime is generally of about the normal specific gravity. It oc-\ncasionally has a light greenish hue. The deposit when allowed to collect in a glass vessel is rarely seen otherwise than as a floating cloud collecting at bottom, and closely resembling the appearance which would be put on by the presence of an excess of the mucus of the bladder natural to the urine.\nIt has recently been stated, by Dr. Frick, of Baltimore, that the crystalline masses, in the form of dumb-bells, described by Dr. Bird as consisting of oxalate of lime, are really composed of lithic acid. It is true that lithic acid occasionally assumes a form more or less resembling the dumb-bells figured by Dr. Bird, but scarcely so nearly as to be easily mistaken for them. Dr. Marris Wilson has also recently shown that lithic acid may be made to assume a form nearly approaching in character to the dumb-bells. I have examined, with Dr. Bird, some specimens of the dumb-bells, and am satisfied that those we operated upon were composed of lime in combination with an organic acid. In a paper recently published by Dr. Bird in the Medical Gazette, some reasons are given by him for believing that acid to be the oxaluric, and not the oxalic, and there would appear good grounds for the adoption of that opinion.\nDeposit of Cystine.\nThis substance, which is not one of the ingredients of normal urine, is an organic body, occasionally existing as a deposit in the form of flattened hexagonal plates. Under the microscope it presents the following appearances (fig. 796).\nFig. 796.\nCarbonate of Lime Deposit.\nThis rare deposit exists in the form of spherical masses, more or less crystalline, and apparently made up of slender rhomboidal prisms, diverging from a centre. It presents the following appearance under the microscope (fig. 797).\nFig. 797.\nHippuric Acid.\nThis exists occasionally in excessive quantity in human urine in disease. Under the microscope it shows the following appearance (fig. 798).\n4 n 2","page":1283},{"file":"p1284.txt","language":"en","ocr_en":"1284\nFig. 798.\nBesides these more or less crystalline deposits, the urine in disease frequently contains blood, mucus and pus corpuscles, and also epithelial scales, and other, bodies of various kinds ; with all of which it is necessary the physician should be familiar, as symptomatic of diff\u00e9rent diseases.\nIn order satisfactorily to detect these, the microscope is of course indispensable.\nThe following are the appearances shown by these more or less organised bodies, when existing in the urineg (Jig. 799).\nFig. 799.\nURINE.\na, Blood corpuscles endosmosed or distended, owing to the entrance of the urine through their membrane. This effect is the consequence of the contained fluid of the corpuscles having been heavier than the urine in which they float, in virtue of which condition more fluid passed into the corpuscle than could escape out. b, Mucous corpuscles, c, Pus corpuscles. d, Scales of epithelium, e, Fibrinous casts of the urinary tubules of the kidney, seen in the morbus Brightii, deposited from albuminous urine \u2014 spheroidal epithelium from the tubules is seen embedded in these fibrinous casts, f Spermatozoa, g, Torula diabetica, seen in diabetic urine during its fermentation.\nA tendency to the secretion in excessive quantity of the unorganised deposits, such as lithic acid and the lithates, oxalate of lime, &c., leads not unfrequently to the formation of urinary calculi. These are either made up, as is most frequently the case, of several of the constituents of the urine, or may be entirely constituted of one of them.\nThe following table, constructed by the late Dr. Prout, exhibits a general view of the relative frequency of the different kinds of urinary calculi in England, Swabia, Germany, andDenmark. The hospitals of St. Bartholomew and of Guy in London, and those of Norwich, Manchester, and Bristol, principally supplied the specimens quoted in this table.\nThe ingredients of particular species of calculi included between parentheses, are to be considered as existing in a mixed state.\n* For further information respecting urinary deposits, I must refer to Dr. Golding Bird\u2019s work on the subject, and my Treatise \u201c on Analysis, and the Treatment of Urinary Diseases.\u201d\nGeneral Character of Calculi.\tParticular Species of Calculi.\t\tEi\tigland.\t\t\t\tConti- nent.\t\t] Particular Totals.\tGeneral Totals.\t\n\t\tBartholomew's Hospital, London.\tt Guy\u2019s Hospital, 1\tLondon.\tNorwich Hospital.\tManchester Hospital.\t\tBristol Hospital.]\tI Swabia, Ger-1\tmany.\tCopenhagen, Denmark.\t\t\t\n1. Lithic acid.\tLithic acid, nearly pure\t11\t16\t164\t\t...\t...\t7\t32\t230\t*\t\nLithate of\tLithate of ammonia, nearly pure\t...\t...\t5.5\t\t...\t\t1\t3\t59\t\t\nammonia.\tLithate of ammonia, mixed with] vari-\t\t\t\t\t\u25ba 71\t74\t...\t...\t145\t\t\u25ba448\n\table proportions of the lithate and\t\t\t\t\t\t\t\t\t\t\t\n\toxalates of lime and phosphates\t8\t1 6\t...\t\t\t\t...\t...\t14\t\t\n2. Oxalate of lime.\tOxalate of lime, nearly pure -\t8\t22\t21\t\t11\t33\t3\t...\t98\t\t98\n3. Cystic oxide.\tCystic oxide, nearly pure\t2\t1\t...\t\t2\t\t...\t...\t5\t\t5\n4. Phosphates.\tPhosphate of lime, nearly pure\t4\t3\t5\t\t...\t1\t...\t...\t13\t\t13\n\tTriple phosphate, nearly pure\t1\t2\t...\t\t...\t1\t...\t8\t12\t\t12\n\tMixed phosphates\t-\t10\t24\t35\t\t4\t18\t7\t8\t106\t\t106\n\t( Phosphate of lime, with carbonate of\t\t\t\t\t\t\t\t\t\t\t\n\tlime)\t-\t...\t...\t\t\t\t...\t1\t1\t2\t\t2\n\t\t\t mixed with a little lithic acid\t...\t...\t...\t\t18\t...\t...\t...\t18\t\t18\n\t\t\t deposited on foreign bodies\t3\t...\t\t\t...\t...\t...\t2\t5\t\t5\nCarbonate of lime.\t(Carbonate of lime and silex)\t...\t...\t...\t\t...\t\t...\t1\t1\t\t1\nSilex.\tSiliceous\t-\t-\t-\t-\t...\t\t...\t\t...\t\t\t1\t1\t\t1\n5. a. Alternating\tLithic acid, and lithate of ammonia\t4\t\t49\t\t...\t...\t...\t1\t54\t\t\ncalculi com-\t\t and oxalate of lime\t3\t\t10\t\t...\t...\t53\t...\t66\t\t\nposed of two\t\t and phosphate of lime\t...\t\t8\t\t...\t...\t...\t...\t8\t\t\nlayers.\t\t\t and mixed phosphates\t6\t...\t15\t\t39\t12\t9\t13\t94\t\t","page":1284},{"file":"p1285.txt","language":"en","ocr_en":"URINE,\n1285\n\t\tEngland.\t\t\t\t\tConti- nent.\t\t\t\nGeneral Character of Calculi.\tParticular Species of Calculi.\tBartholomew\u2019s Hospital, Lon-| don.\tI Guy\u2019s Hospital, 1\tLondon.\tNorwich Hos- pital.\tManchester Hospital.\tj Bristol Hospital.\tSwabia, Ger- many.\tCopenhagen, 1 Denmark.\t|\tParticular Totals\tGeneral Totals.\n5. a. Alternating calculi composed of two layers.\t(Lithic acid, lithate of ammonia,) and (lithate of magnesia and mixed phosphates)\t- (Lithic acid and lithate of lime) and mixed phosphates) -(Lithic acid, lithate and oxalate of lime,) and lithic acid (Lithic acid, lithate of ammonia and oxalate of lime,) and mixed phosphates Lithate of ammonia and lithic acid\t2 7\t...\t21 63\t...\t...\t...\t2 2 27 2\t; 2 2 27 2 23 70\t\n\t\t\u2022 \u2022\u2022\t...\t9\t\t...\t...\t...\t9\t\n\t\t13\t\t22\t\t...\t...\t...\t35\t\n\tLithate of soda and lithic acid Lithate of lime, and (lithate and oxalate of lime and lithate of ammonia) (Lithate and oxalate of lime,) and oxalate of lime\t- (Lithate of ammonia and of lime,) and lithate of ammonia and lime, alternately\t- Oxalate of lime and lithic acid\t3 1\t...\t15 3\th\t29\t...\t1 1 8 2 3\t1 1 8 2 61 4\t\u25a0 566\n\t\t...\t\t7\t...\t...\t...\t...\t7\t\n\t\t13\t\t20\t16\t32\t...\t...\t81\t\n\t\t\t\t\t\t\t\t\t\t\n\tphosphates)\t...\t\t1\t...\t...\t...\t1\t1 1\t\n\tMixed phosphates and oxalate of lime \tand phosphate of lime Phosphate of lime and mixed phosphates\t-\t...\t\t1 2 3 1\t...\t...\t...\t...\t1 2 3 1\t\nb. Alternating calculi composed of three layers.\tLithic acid, oxalate of lime, and phosphate of lime\t-\t-\t- - oxalate\tl'rn*3, \u00abmd lithate of\t...\t...\ts\t...\t...\t...\t...\t2 '\t\n\tammonia -\t-\t\u25a0 \t,t oxalate of lime, and lithic acid\t...\t...\t4 5\t...\t...\t...\t...\t4 5\t\n\tlate of lime -\t- lithate of ammonia, and lithic\t...\t...\t2\t...\t...\t...\t...\t2\t\n\tacid\t-\t- lithate of ammnnia and plins-\t...\t...\t2\t...\t...\t...\t...\t2\t\n\tphates\t- oxalate of lime and phos-phates\t- (Lithic acid and lithate'of lime,) oxalate of lime and mixed phosphates -(Lithic acid, lithate and oxalate of lime) lithic acid and mixed phosphates Lithate of ammonia, oxalate of lime, and mixed phosphates oxalate of Hme, and phosphate\t3 1 13\t...\t2 3 13\t...\t...\t...\t2 17\t5 4 2 17 26\t\n\tof lime\t-\t-\t- ^ oxalate of lime and, lithic acid\t1\t...\t13 16\t\t...\t...\t...\t13 17\t\n\toxalate of lime, and lithate of\t\t\t\t\t\t\t\t\t\n\tammonia -\t-\t\" phosphate of limp, and lithate\t1\t...\t7\t\t...\t\t...\t8\t\n\tof ammonia\t-\t-\t- phosphat0 of limp and lithic\t...\t...\t1\t...\t...\t...\t...\t1\t\n\tacid\t- phosphate of limp and oxalate\t\u2022 \u2022 \u2022\t...\t1\t\t...\t...\t...\t1\t> 172\n\tof lime\t-\t-\t- phosphate of lime, and mixed\t\u2022 \u2022\u2022\t...\t1\t\t...\t\t...\t1\t\n\tphosphates -\t\t\t, 4\t1 .\t1 -\t, ... 4\tb N :\t. 4 3\t","page":1285},{"file":"p1286.txt","language":"en","ocr_en":"1286\nURINE\nGeneral Character of Calculi.\nb. Alternating calculi composed offeree layers.\nc. Alternating calculi composed of four layers.\nd. Alternating calculi composed of several layers.\n6. Mixed or compound calculi.\nParticular Species of Calculi.\nLithate of ammonia, lithic acid, and phosphates\t-\n-------, lithic acid, and lithate of ammonia -\n-------, lithic acid, and phosphate of lime\n------, lithic acid, and oxalate of lime\n(Lithate and oxalate of lime,) oxalate of lime, and mixed phosphates (Lithate and oxalate of lime,) (ditto alternately,) and phosphates -Oxalate of lime, lithic acid and lithate of ammonia\t-\n-------, lithic acid and oxalate of lime\n-------, lithic acid, and phosphate of\nlime\t-\n-------, lithic acid, and mixed phosphates\t-\n-------, lithate of ammonia, and phosphate of lime\t-\n-------, lithate of ammonia, and oxalate\nof lime\t-\nMixed phosphates, phosphate of lime, and mixed phosphates Lithic acid, lithate of ammonia, lithic acid, and lithate of ammonia -------, oxalate of lime, lithate of ammonia, and phosphate of lime\n-------, oxalate of lime, lithic acid and\noxalate of lime -\t-\t-\n-------, oxalate of lime, lithic acid, and\nlithate of ammonia -\t-\t-\nLithate of ammonia, oxalate of lime, lithate of ammonia, and phosphates -------, oxalate of lime, lithate of ammonia, and oxalate of lime -\n-------, oxalate of lime, phosphates\nand oxalate of lime -\n-------, oxalate of lime, lithic acid,\nand lithate of ammonia\n-------, oxalate of lime, phosphate of\nlime, and phosphates\n-------, oxalate\tof\tlime,\tlithic\tacid,\nand phosphates\t-\n-------, oxalate\tof\tlime,\tlithic\tacid,\nand oxalate of\tlime\n-------, oxalate of lime, lithate of ammonia, and lithic acid\n-------, phosphate of lime oxalate of\nlime, and lithate of ammonia Oxalate of lime, lithic acid, lithate of ammonia, and lithic acid\n-------, lithic acid, oxalate of lime, and\nphosphate of lime -\n-------, lithic acid, oxalate of lime, and\nphosphates -\n-------, lithic acid, lithate of ammonia,\nand phosphates -Composition not mentioned -\nMixture not mentioned Fibrous matter and phosphates\nEngland.\t\t\t\t\tConti- nent.\t\t\tGeneral Totals.\nBartholomew\u2019s Hospital, Lon- don.\tGuy\u2019s Hospital, London.\tNorwich Hos- pital.\tManchester Hospital.\tBristol Hospital.\tSwabia, Ger- many.\tCopenhagen, Denmark.\tParticular Totals\t\n1\t...\t6\t...\t...\t...\t...\t7\t\n...\t\t1\t...\t\t...\t...\t1\t\n...\t...\t4\t...\t\t...\t...\t4\t\n...\t\t3\t...\t\t...\t...\t3\t\n...\t\t...\t...\t\t\t13\t13\t\n...\t...\t\t...\t\t\t3\t3\t\n1\t\t3\t...\t...\t\t\t4\t\n1\t...\t3\t...\t...\t\t...\t4\t\n\t...\t1\t...\t...\t...\t\t1\t\n\t...\t5\t7\t...\t...\t\t12\t\n\t...\t3\t...\t...\t...\t...\t3\t\n\t...\t2\t...\t\t...\t\t2\t\n\t...\t1\t...\t...\t...\t\t1\t_\n\t...\t1\t...\t...\t...\t\t1\t-\n\t...\t1\t...\t...\t...\t\t1\t\n...\t...\t1\t...\t...\t...\t\t1\t\n...\t...\t2\t...\tV\t...\t\t2\t\n\t\t5\t...\t...\t...\t\t5\t\n\t...\t3\t...\t...\t...\t\t3\t\n...\t...\t2\t...\t...\t...\t\t2\t\n\u2022 \u2022 \u2022\t...\t1\t...\t\t...\t...\t1\t\n\u2022 \u2022 \u2022\t...\t1\t...\t...\t...\t...\t1\t. 25\n...\t...\t1\t...\t...\t...\t\t1\t\n\t...\t1\t...\t...\t...\t...\t1\t\n\t...\t1\t...\t...\t...\t\t1\t\n...\t...\t1\t...\t...\t...\t\t1\t\n...\t...\t1\t...\t...\t...\t\t1\t\n\t...\t1\t...\t...\t...\t...\t1\t\n\t\t1\t...\t...\t...\t\t1\t\n...\t\t1\t...\t...\t...\t...\t1 .\t.\n8\t6\t...\t...\t10\t...\t...\t24\t24\n\t7\t\t8\t8\t\t\t23\t23\n...\t\t...\t...\t...\t...\t1\t1\t1\n129\t87\t663|\t187\t218\t81\t155|\t...\t1520","page":1286},{"file":"p1287.txt","language":"en","ocr_en":"URINE.\t1287\nTo this table Dr. Prout appends the following valuable remarks in his work \u201c On Stomach and Urinary Diseases \u201d : \u2014\n\u201c In this table the urinary calculi contained in the museums of Bartholomew\u2019s and Guy\u2019s Hospitals in London, and of the provincial hospitals of Norwich, Manchester, and Bristol, are contrasted with the calculi existing in Swabia in Germany, and in Copenhagen in Denmark. The data here collected are too limited to throw much light on the relative prevalence of calculous affections in different parts of England, much less in England as compared with the different countries of Europe ; yet in other points of view, and particularly in demonstrating the relative prevalence of the different species of calculi, and the order of the succession of the different layers of which calculi are composed, &c., they are highly interesting and important.\n\u201c In this table, the whole of the data comprising the analysis of 1520 calculi, are collected into one point of view, under the general heads of 1. Lithic acid, 2. Mulberry, 2. Cystic oxide, 4. Phosphatic, 5. Alternating, and 6. Compound Calculi.\n\u201c On each of these heads we shall make a few remarks.\n\u201c 1. Of lithic acid calculi.\u2014The proportions of pure lithic acid calculi to the whole numbers contained in the different museums, are as follow : \u2014 In Bartholomew\u2019s Hospital, as 1 : 11-^L ; in Guy\u2019s Hospital, as 1 : 5+ ; in the Norwich Hospital, as 1 1 4+ ; in Swabia, as 1 : Ilf ; in Copenhagen, as 1 : 5\u2014. The relative proportions of pure lithic acid calculi in the Manchester and Bristol Museums are not mentioned ; hence, abstracting the Manchester and Bristol, the general proportion of pure lithic acid calculi is as 1 : 6+ nearly.\n\u201c The relative proportions of calculi in the different museums, composed essentially of lithic acid, (i. e. consisting of pure lithic acid, lithate of ammonia, and the latter ingredient mixed with minute quantities of the lithate and oxalate of lime, and the phosphates,) are, in Bartholomew\u2019s Hospital, as 1 : 7\u2014 ; in Guy\u2019s Hospital, as 1 : 4\u2014 ; in the Norwich Hospital, as 1 : 3+ ; in the Manchester Hospital, as 1 : 2f+ ; in the Bristol Hospital, as 1 : 3\u2014 ; in Swabia, as 1 : 10+ ; and in Copenhagen, as 1 : 4f\u2014. The general proportion in all the collections is as 1 I 3f\u2014.\n\u201c If we take into account all the calculi of which the lithic acid or its compounds form the nucleus, the proportions of calculi originating with this principle (and which probably would otherwise have not been formed) is very much greater. Thus in Bartholomew\u2019s Hospital the proportion of calculi containing the lithic acid or some of its compounds as a nucleus, is to the whole number of calculi as 1 : If\u2014 ; in Guy\u2019s Hospital, as 1 : 4\u2014, (not fairly comparable, as the calculi do not appear to be divided ;) in the Norwich Hospital, as 1 : If + ; in the Manchester Hospital, as 1 : If\u2014 ; in the Bristol, as 1 : 2f + ; in Swabia, 1 : lf+ ; and in Copenhagen, as\n1 : If. The relative proportions of all the calculi originating in some form or combination of lithic acid, in all the different collections, is nearly as 1 : If, which is equal to saying, that if a lithic acid nucleus had not been formed and detained in the bladder, two persons at least out of three who suffer from calculus would have never been troubled with that affection.\n\u201c Of mulberry or oxalate of lime calculi. \u2014 The proportions of mulberry calculi in the different hospitals are nearly as follow : in Bartholomew\u2019s Hospital, as 1 : 16+; in Guy\u2019s Hospital, as 1 : 4\u2014 ; in the Norwich Hospital, as 1 : 3If \u2014 ; in the Manchester Hospital, as 1 : 17; in the Bristol Hospital, as 1 : 6f\u2014 ; in Swabia, as 1 : 27 ; in Copenhagen there does not appear to be any calculus composed throughout of oxalate of lime ; but if we take the nearest approach to such composition, in which calculi are composed principally of this salt with a mixed nucleus, likewise containing oxalate of lime, the proportions will be as 1 : 19f\u2014 ; the general proportions in all the museums are as 1 : 14+\n\u201c If we take into account all the calculi of which the oxalate of lime constitutes more or less of the nucleus, the proportions in the different museums will be, \u2014 in Bartholomew\u2019s, 1 : 4f + ; in Guy\u2019s, 1 : 4\u2014 ; in Norwich, 1 : 7f + ; in Manchester, 1 : 4f + ; in Bristol, 1 : 3f \u2014 ; in Swabia, 1 : 27 ; and in Copenhagen, 1 :\t. The general pro-\nportion of calculi, into the nucleus of which oxalate of lime largely enters, in all the museums, is as 1 : 4f + ; which is equivalent to saying, that if a mulberry stone had not been formed and detained in the bladder, two persons out of about nine who suffer from calculus would not have been troubled with that affection.\n\u201c 3. Of cystic oxide calcidi. \u2014 Of this rare form of urinary calculus, four out of the seven museums contain no specimen. Calculi of this substance exist in the museums of Bartholomew\u2019s, Guy\u2019s, and the Manchester Hospitals, amounting altogether to five only. Hence the general proportion to the whole number of cystic oxide calculi examined, is only as 1 : 304.\n\u201c 4. Of phosphatic calculi. \u2014 Calculi composed throughout of the phosphates are comparatively of uncommon occurrence; while calculi consisting externally of the phosphates, as will be presently shown, are the most frequent of all others. At present we have to do with calculi composed essentially of the phosphates.\n\u201c The proportion of calculi composed of the phosphate of lime, in Bartholomew\u2019s Hospital, is as 1 : 32^ ; in Guy\u2019s Hospital, as 1 : 29 ; in the Norwich Hospital, as \u00ce : 132\u00a7 ; in the Bristol, as 1 : 155. The other museums contain no specimen. The general proportion of phosphate of lime calculi, to the whole number, is as 1 : 117\u2014.\n\u201c The proportion of calculi composed of the\n4 n 4","page":1287},{"file":"p1288.txt","language":"en","ocr_en":"1288\nURINE.\npure triple phosphate is still less; thus in Bartholomew\u2019s Hospital the proportion is as 1 : 129 ; in Guy\u2019s, as 1 : 43\u00a3 ; in the Bristol, as 1 : 218 ; in Copenhagen, as 1 : 19|\u2014. The other museums contain no specimen. The general relation of the triple phosphate in all the collections, is as 1 : 126f.\n\u201c On the other hand, the proportion of calculi composed of the mixed phosphates is very considerable ; thus, in Bartholomew\u2019s Hospital, the proportion is as 1 : 12T% ; in Guy\u2019s, as 1 : 3\u00a3+ ; in the Norwich, as 1 : 19\u2014; in the Manchester, (including those containing a little lithic acid,) as 1 : 8\u00a3 ; in the Bristol, as 1 : 12 + ; in Swabia, as 1 : 11J+; in Copenhagen, as 1 : 19f. The relative proportion of the mixed phosphates in all the collections is as 1 : 12^-f.\n\u201c Under the head of the phosphates are included a few rare specimens of other calculi, e. g. carbonate of lime and siliceous calculi. Of these two varieties, there is only one of each reported to exist in the Copenhagen collection ; and one containing silex in the Norwich collection.\n\u201c The general proportion of all the calculi arranged under the heads of the phosphates, in the different museums, is as 1 : 10\u2014.\n\u201c 5. Of alternating calculi. \u2014 Calculi composed of different layers constitute by far the most frequent results of urinary diseases ; of the successive forms assumed by which, they may be said to constitute the index. We shall first consider the relative proportions of the calculi composed of two, three, and four deposits ; and afterwards of the whole conjointly.\n\u201c The proportion of alternating calculi composed of two deposits is, in Bartholomew\u2019s Hospital, as 1 : 2\\\u2014 ; in Guy\u2019s, none are reported, probably on account of the calculi not having been divided ; in Norwich, the proportion of alternating calculi composed of two layers is stated to be as 1 : 2f\u2014 ; in Manchester, as 1 : 2f ; in the Bristol, as ] ; 3\u2014 ; in Swabia, as 1 : l\u00a3+ ; and in Copenhagen, as 1 : 2\\\u2014. The proportion of alternating calculi composed of two layers, in the conjoint collections, is as 1 : 2f+.\n\u201c The proportion of alternating calculi composed of three deposits, is, in Bartholomew\u2019s Hospital, as 1 : 6\u2014 ; in Guy\u2019s Hospital, none is reported ; in the Norwich Hospital, the proportion is as 1 : 6-f- ; in the Manchester, as 1 : 26-f- ; in the Bristol and Swabia collections, none is reported ; in Copenhagen, the proportion is stated to be as 1 : 4\u00a3\u2014. The proportion in all the collections, is as 1 : 8-\u00a7\u2014.\n\u201c Alternating calculi composed of four deposits are only reported to exist in the Norwich Hospital, and the proportion stated is as } ; 26|+. In the different collections there are twenty-four alternating calculi, the composition of which is not stated. The proportion of all the varieties of alternating calculi in the different collections, is somewhat more than one-half ; that is, as 1 ; 2\u2014,\n\u201c 6. Of mixed or compound calculi. \u2014 In one sense of the term, all calculi may be said to be mixed or compound, as there are perhaps none absolutely pure, i. e.y formed of a single ingredient. But in the sense in which the term is here applied, namely, as expressive of calculi composed of different ingredients mixed together in large or nearly equal proportions, compound calculi may be said to be rare. The most usual mixtures consist of the lithate of ammonia and of lime ; of the oxalate, carbonate, and phosphate of lime ; of the lithate of ammonia, and the mixed phosphates, &c. ; and such mixtures are usually confined to small calculi or calculous nuclei. Calculi composed of pure lithic acid, or of any other pure ingredient, with the phosphates or other compounds, do not appear to exist ; at least I have met with no such mixtures.\n\u201c Lastly, it remains to make a few remarks on the order of calculous deposits ; an inquiry that throws considerable light on the laws of their formation and general pathology.\n\u201c On reference to the table it will be found, that in the different alternating calculi, the ratio in which the oxalate of lime succeeds to lithic acid, is as 1 : 15J-+ ; on the contrary, that the ratio in which lithic acid succeeds to oxalic acid, is as 1 : lS/g-. Hence the alternation of the two ingredients may be considered as nearly equal. It will be found, however, that the oxalate of lime succeeds to the lithate of ammonia, &c., more frequently than to lithic acid ; thus the ratio in which the oxalate of lime succeeds to the lithate of ammonia was 1 ; 9f\u2014. On the contrary, the ratio in which the lithate of ammonia succeeds to the oxalate of lime, is only as 1 : 38 ; a very striking distinction. The ratio in which the phosphates succeed to lithic acid, is as 1 : 9\u00b1\u2014 ; in which the phosphates succeed to the lithate of ammonia, is as 1 : 12J\u2014 ; and in which the phosphates succeed to the oxalate of lime, is as 1 : 7\u00a3+. On the contrary, three instances only occur in which the lithic acid or lithate of ammonia succeeds to a phosphate ; and the proportion in which the oxalate of lime succeeds to the phosphates is as 1 : 253\u00a3 only. The general proportion in which the phosphates succeed to the other ingredients in all the collections, is as 1 : 4^5+\u2022 Hence the generality of the important law alluded to in various parts of this volume, that in urinary calculi a decided deposition of the mixed phosphates is not followed by other depositions.\u201d\nThe following table, constructed by Dr. Prout, illustrating the frequency of calculous affections at different ages, and in the different sexes, is from a paper published by Mr. Smith in the eleventh volume of the Med. Chirurg. Transactions, and from \u201c A Treatise on the Formation, Constituents, and Extraction of Urinary Calculi. By John Green Crosse, Esq., Surgeon to the Norfolk and Norwich Hospital. London, 1835.\u201d","page":1288},{"file":"p1289.txt","language":"en","ocr_en":"URINE.\n1289\n\t\t\trC\t<D . \u00d6 \u2014\n\tO\t\ts O\t13 o oS\n\tPQ\t\tfc\tHco\nUnder 10 years\t\t\t\t\nof age\t136\t83\t281\t500\nBetween 10 and\t\t\t\t\n20\t65\t21\t106\t192\n20 and 30 -\t35\t21\t48\t104\n30 and 40 -\t34\t12\t48\t94\n40 and 50 -\t37\t28\t47\t112\n50 and 60 -\t28\t21\t96\t145\n60 and 70 -\t18\t9\t70\t97\n70 and 80 -\t2\t2\t8\t12\n\t355 197\t\t704\t1256\na _ \u00ab \u2018\u25a0g 8 g\n\"g 3 \u00ab\nUrine in disease may not only show a tendency to deposit matters of an insoluble character in the form of urinary deposits or calculi, but it may also contain in solution an excess or deficiency of any one or more of its normal constituents. There may likewise be present in solution matters altogether foreign to the healthy constitution of the fluid. The urine in disease may then, so far as its dissolved matters are concerned, be considered in two points of view, viz. 1. Excess or deficiency of normal constituents ; 2. Presence of matters not existing in healthy urine.\nI shall proceed to notice the state of the urine in those forms of disease in which it has received attention, and shall quote from the work of Franz Simon, who not only laboured long and well on the subject, but collected much valuable information relating to it. Before doing this, however, I must notice the ingenious attempt made by Becquerel to classify all diseased conditions of urine under four heads, viz. 1. Febrile urine ;\n2.\tAnaemic urine ; 3. Alkaline urine ; 4. Urine but slightly varying from the conditions of health.\nI will shortly notice the principal characters of these four varieties.\n1. Febrile urine. \u2014 a. Febrile urine, strictly speaking.\u2014The proportion of water passed in the twenty-four hours less than in health. Solid matters slightly diminished in proportion. Urea and inorganic salts deficient. Uric acid increased in proportion. Colour high. Specific gravity above the normal standard. Often turbid from lithates. Sometimes contain albumen.\nThis latter statement of Becquerel\u2019s must be received with some reservation. Thus I have several times known a deposit produced in urine in adynamic forms of fever on the addition of nitric acid, which proved, on examination, to be lithic acid and not albumen.\nThe following are the conditions in which, according to Becquerel, the urine assumes the febrile character ; viz., in chronic and acute inflammations ; in diseases of the liver, heart, and lungs; in haemorrhages, and in organic degenerations of organs resulting from fever or long functional derangement.\n\u00df. Febrile urine, with debility. \u2014 The pro-\nportion of water diminished. Specific gravity less than in a. Solid matters also less in the twenty-four hours. Uric acid in normal proportion. All other constituents absolutely but not relatively diminished. This urine is then less concentrated than that of health. It is deeply coloured, often turbid from deposit of uric acid. It occurs in adynamic fevers.\ny. Febrile urine containing the natural proportion of water. \u2014 Urea and fixed salts diminished in proportion. Uric acid and other organic matters normal. Specific gravity low. Colour deep. No sediment.\n2.\tAn\u00e6mic urine. \u2014 a. True anaemic urine.\u2014 Water in the twenty-four hours nearly normal. Solids discharged much less than in health. Urea, uric acid, and fixed salts diminished. Other organic matters decreased in slighter degree than the above. Specific gravity low. Colour light. No sediment.\n\u00df. \u2014 Concentrated an\u00e6mic urine.\u2014Water in twenty-four hours diminished, although the solids are then relatively increased, still they are absolutely diminished. Urea, uric acid, and fixed salts especially diminished. Other organic matters less so. Urine of livid or greenish tint.\n3.\tAlkaline urine.\u2014Distinguished by alkaline reaction on test paper. Odour ammoniacal : occurs in acute and chronic nephritis, diseases of the bladder with secretion of pus, and in certain cerebral diseases; occasionally in the \u201c morbus Brightii.\u201d\n4.\tUrine nearly normal. \u2014 Nearly that of health. Occurs in mild disorders unaccompanied by fever.\nWith respect to this classification of Becquerel, it may be observed that the heads of arrangement by no means embrace all the forms of diseased urine met with in practice, \u2014an end, indeed, which will scarcely be compassed by any attempts of the kind. There appears no advantage in making such classifications; and indeed much evil must result from the necessary endeavour which will be made in such a table to place diseases under headings which either imperfectly or incorrectly express their real character. The table, however, is of some value, as showing the general results obtained in fevers and in anaemia ; but further than this the student need not regard it.\nThe following introductory remarks by Franz Simon are extremely valuable, and will well repay the reader for the trouble taken in their careful perusal. I transcribe them from Dr. Day\u2019s translation for the Sydenham Society: \u2014\n\u201c In inflammatory affections, and in those diseases which are accompanied by that form of fever which is termed sthenic or synochal, the urine differs greatly in its properties from normal urine. In speaking of the probable cause of the changed constitution of the blood in the phlogoses, I showed that it is not to be referred to the diseased organ, but to the reaction which manifests itself throughout the vascular system. If the change in the constitution of the blood bears an accurate and inseparable relation to the fever, there can be","page":1289},{"file":"p1290.txt","language":"en","ocr_en":"URINE.\n1290\nno doubt that the change in the constitution of the urine must be in relation to the same cause; for the urine is separated from the blood, and was previously an integral constituent of it: and because, further, every alteration in the constitution of the blood must involve corresponding changes in the secretions and excretions, and more especially in the urine. Since like effects follow like causes, and since in inflammatory affections the vascular system similarly participates in the disturbance, we may assume \u00e0 priori that similar changes will occur in the urine,\u2014a point confirmed by experience.\n\u201c The urine discharged during inflammations is usually termed febrile urine. There is no objection to this term, since the cause of the change in the urine must be sought for in the fever. I shall not, however, introduce the term ' febrile urine \u2019 here, since it is more than probable that the changes in the composition of the urine vary according as the character of the fever is synochal or torpid.\n\u201c My analyses show, in fact, that the relative proportions of urea in fevers of a torpid and of a synochal character are different ; and although the analyses are not yet sufficiently numerous to establish the difference with certainty, it still appears to me to be a point of sufficient importance to demand attention, and one that should be carefully worked out. In order to take a correct view of the composition of the urine, we must bear in mind the composition of the blood, the reaction of the vascular system, and the diet, since the mixture of the proximate constituents is dependent upon these circumstances.\n\u201c The following are the general characteristics of the urine in inflammatory affections. It is darker than usual, and of a yellow, brown, or reddish-brown tint ; it has an acid reaction, and is generally of a high specific gravity. With respect to its most important constituents, the urea is either absolutely increased, or is at the ordinary physiological average, or may be a little below it ; the uric acid is always absolutely increased, and so are the extractive matters, especially the alcoholic extract. The salts are always absolutely diminished, especially the chloride of sodium. The sulphates, on the other hand, either approximate to the physiological average, or are not far below it.\n\u201c Assuming as the mean of numerous analyses, that the urea constitutes 39 per cent, of the solid residue of normal urine, I have found it as high as 46*8 in inflammatory affections. (In abdominal typhus, with a quick small pulse, I have seen it as low as 22.)\n\u201c The physiological average of uric acid may be placed at; 1*5 per cent, of the solid residue ; in the phlog\u00f4ses I have observed it amount to nearly 3 per cent., and Becquerel even found it rise as high as 5*9 per cent. The quantity of extractive matter, &c., which in normal urine amounts to 23'5 per cent, of the solid residue, rises in inflammations to 43 per cent. The fixed salts, which in healthy urine con-\nstitute about 25 per cent, of the solid residue) diminish here to 12 per cent. The sidphate of potash, which in healthy urine forms about 10 per cent, of the solid residue, I found to vary in inflammation between 7 and 9 per cent.\n\u201c The composition of the urine becomes changed if much blood is abstracted during the inflammation. It becomes clearer, specifically lighter, and the amount of urea decreases absolutely and relatively.\n\u201c At the height of the inflammation, or (perhaps it would be better to say) at the time when the fever puts on the synochal type most strongly, the urine is usually clear and deeply coloured ; it subsequently forms a sediment of a yellow or red colour, composed of uric acid and urates.\u201d\nI shall now proceed to describe the state of the urine as it is observed in different diseases.\nPericarditis. \u2014 A man aged 36. Acute pericarditis ; pulse 108, full, and hard ; urine clear, deep red colour; specific gravity 1023*5; indications of albumen by heat. Analysis showed : \u2014\nWater -\t-\t937*50\nSolid residue -\t-\t62*50\nUrea -\t_\t29*30\nUric acid\t-\t1*50\nExtractive matters -\t-\t22*70\nEarthy phosphates -\t-\t0*55\nSulphate of potash -\t-\t4*89\nPhosphate of soda -\t-\t- Chloride of sodium, and carbonate\t\t0*56\nof soda\t-\t1*40\nIn the above case, after a large quantity of\t\t\nblood had been drawn, follows. Colour, that\tthe urine changed as\t\n\tof health ;\tacid re-\naction ; devoid of albumen ; specific gravity 1018. Its composition was now,\u2014\t\t\nWater -\t_\t960*10\nSolid residue\t-\t39 90\nUrea -\t-\t17*50\nUric acid\t-\t0*99\nExtractive matters\t-\t15*10\nFixed salts\t-\t3*65\nThe first of these analyses is that of inflammatory urine. The second shows the effects of the copious bleedings in reducing the excretion nearer to the normal standard.\nWith respect to the presence of albumen in the urine in this and other inflammatory affections unconnected with disease of the kidneys, there is in my mind no doubt whatever that the opinion is founded in error. There is no institution in the world at which the question has been so thoroughly investigated as at Guy\u2019s Hospital; and our daily experience still confirms the opinions arrived at by Dr. Bright in his first experiments. It will be observed that the test of heat (a most inefficient one in itself) is alone referred to in the above-described case ; and I have little doubt the precipitate produced was composed of phosphate of lime, a common source of","page":1290},{"file":"p1291.txt","language":"en","ocr_en":"URINE.\t1291\nfallacy which I pointed out some years ago in connection with this subject.*\nPhlebitis Uterina.\nThe following is a description, by F. Simon\u00bb of specimens of urine in this disease. 1. Colour dark ; reaction acid ; deposit of uric acid and urate of ammonia. 2. Colour dark ; alkaline reaction ; ammoniacal odour ; deposit dirty yellow in colour, composed of mucus, ammoniaco-magnesian phosphate, amorphous precipitate of phosphate of lime, and urate of ammonia.\nMeningitis.\nThe urine in this disease assumes the ordinary inflammatory type. It is described as dark red, scanty (8 to 9 fluid ounces in the twenty-four hours), strongly acid ; specific gravity high. According to Becquerel, the mean of four cases was 1025'2. Deposit of uric acid, which, if not present spontaneously, is immediately produced by the addition of nitric acid.\nEncephalitis.\nUrine much the same as in meningitis ; sometimes a sediment. Spec, gravity, 1020\u20192.\nObservations have been made by several foreign writers on the state of the urine in insanity. Drs. Sutherland and Rigby have also paid some attention to the subject. It appears to be generally alkaline, and to contain much ammonia in these cases ; the whole subject, however, needs further and careful investigation. Dr. Bence Jones states, that in acute inflammation of the brain there is an increase in the total amount of phosphates excreted in the urine.\nDelirium Tremens.\nIn this disease the urine is said to present the general features of the inflammatory type.\nDr. Bence Jones states, that in delirium tremens the phosphates are decreased in quantity in the urine, provided no food is taken. If food be taken, this diminution is not observed.\nMyelitis.\nIn this disease the urine is of much the same character as in inflammation of the brain, viz. red, acid, thick, and containing a sediment. Cases are, however, recorded by Becquerel, in which the urine did not greatly vary from the natural standard. There appears no excessive excretion of the phosphates in this disease, according to Dr. Jones\u2019s experiments.\nBronchitis.\nAll that we gather worthy of notice from the detailed examinations of Becquerel in respect to the state of the urine in this disease is, that it occasionally contains albumen. This may perhaps sometimes happen when great obstruction to the circulation of blood through the lungs has existed for any length\n* For the proper method of examining the urine in order to determine the presence or absence of albumen, I beg to refer to my work on Diseases of the Kidney connected with albuminous urine.\nof time. In by far the greater number of cases, however, no indication of this kind is found, unless the kidneys be predisposed to such form of disease as favours the effusion of serum.\nPneumonia.\nIn pneumonia the urea excreted is less than in health ; the uric acid is increased, the salts diminished, and the extractive matters increased, and more especially the alcoholic extract.\nThe following are comparative analyses of the solid matters in 100 parts : \u2014\nUrea - -\tBecquerel. - 37-6\tSimon. 39-0 37-2\t\tUrine of health. 39-0\nUric acid -\t- 2*0\t1*7\t2-8\t1-5\nFixed salts\t- IPO\t18-3\t14*0\t25*8\nExtractives\t- 45-4\t40-0\t370\t23-6\nSulphate of potassa\t\t9\t\t10-3\nDuring the resolution of pneumonia, Simon and Sch\u00f6nlein have observed that a deposit occurs in the urine composed of the monobasic ammoniaco-magnesian phosphate. Uric acid was also thrown down on the addition of acids. This latter reaction, however, is not peculiar to this disease, I having myself often observed it in low forms of fever and also in small-pox. Heller relates the case of a boy in which the urine had the odour of hydrosulphate of ammonia, and deposited urate of soda.\nPleuritis.\nIn this disease the urine in general exhibits much the same characters as in pneumonia.\nEmpyema.\nIn cases of empyema the urine has been observed to contain pus by Sch\u00f6nlein and Simon. The empyema gradually disappeared, the urine containing albumen, and the deposit, when examined, showing the ordinary pus corpuscles.\nHepatitis.\nIn hepatitis the urine is extremely deficient in urea, according to Rose, who in one case believed it absent. Henry agrees in this opinion ; and Coindet states that, instead of urea, the urine contains a substance resembling bilin. Simon and Becquerel, however, differ from Rose and Henry, and mention a case of hepatitis in which urea was excreted in excess.\nNephritis.\nIn this disease, when it assumes the acute character, the urine is often bloody and very acid, and deposits the uric acid crystalline deposit. In arthritic nephritis the quantity of the uric acid crystals is sometimes extremely great. In a case mentioned by Sch\u00f6nlein the sediment occupied half the volume of the urine.\nChronic Nephritis, Albuminous Nephritis, Morbus Brightii.\nIn the morbus Brightii the urine contains abundance of albumen. Blood is occasionally observed in the early stages. It is generally acid, far less frequently alkaline, and occasion-","page":1291},{"file":"p1292.txt","language":"en","ocr_en":"URINE.\n1292\nally neutral. Its specific gravity is nearly always lower than that of health. The uric acid is usually in very small proportion, and sometimes altogether absent. This is not, however, always the case ; and I have sometimes seen the lithic acid in excess existing as a deposit. Simon believes albumen not unfrequently present in diseases quite unconnected with affections of the kidneys. His facts, however, are not satisfactorily stated, and I believe him to have been greatly mistaken in this opinion. In connection with the morbus Brightii, we have to notice two substances which, according to Heller, are often present as deposits in that disease, viz. uroglaucin and urrhodin. These are colouring matters, derived by oxidation from uro-xanthin, or a yellow colouring matter of urine, which exists only in small proportion in healthy urine, but which is greatly increased in Bright\u2019s disease. The deposits observed in the morbus Brightii consist of the casts of the urinary tubules of the kidney \u2014epithelium of two kinds, viz. spheroidal and pavement epithelium. ( Vide woodcut of urinary deposits, fig. 799.)\nCystitis.\nThe urine in this disease is alkaline, the alkalinity increasing rapidly after the urine is voided, owing to the formation of carbonate of ammonia. Mucus and pus are present in quantity. Albumen can always be detected in solution when the pus corpuscles are present in the deposit. As cure is effecting, this albumen is found to decrease in proportion as the pus corpucles disappear.\nTvphus.\nIn typhus the urine shows no great variation from the normal standard, so far as specific gravity and amount of solid constituents is concerned. The urea is generally in deficient proportion, the uric acid increased. The salts are much diminished. During the progress of typhus, the urine very generally becomes alkaline. Becquerel and Andral \"have made many experiments on the state of the urine both in typhus and typhoid fevers. They both have met with a large number of cases in which it was pr\u00e9cipitable by nitric acid ; this is quite in accordance with my own observations ; the precipitate, however, is lithic acid, and not albumen.\nScherer found, like former observers, that the salts were much decreased in the urine of typhus, and that there was always an excess of uric acid.\nThe following analyses are worthy of note. They were made by Scherer at the 9th, 12th, and 15th day of a slow nervous fever, which occurred in the person of a woman aged thirty-eight years.\nJ\t9th Day.\nWater -\nUrea\nUric acid - . \u25a0\nAlcoholic extractive\nWatery ditto -\nAlbumen\t-\t1-80\nFixed salts soluble in water\t6-20\nEarthy phosphates -\t2-30\n12th Day.\t\nWater -\t- 951-26\nUrea\t-\t-\t-\t-\t-\t10-40\nUric acid\t0-70\nAlcoholic extractive\t- 21-80\nWatery ditto\t7'90\nAlbumen\t-\t1-00\nFixed salts soluble in water\t5-30\nEarthy phosphates -\t1-20\n15 th Day.\t\nWater\t-\t-\t-\t- 959-29\nUrea\t-\t-\t11-40\nUric acid\t-\t0-80\nAlcoholic extract\t15-70\nWatery ditto -\t6-20\nAlbumen and mucus\t0 90\nFixed salts soluble in water\t4-50\nEarthy phosphates\t0-60\nIt will be observed that, as\tthe disease pro-\ngressed, the urea increased,\twhile the ex-\ntractive matters diminished.\tThe \u201csalts so-\nluble in water\u201d also diminished in quantity.\nIntermittent Fever.\nL\u2019H\u00e9ritier has made analyses of the urine in this disease, and has drawn up the following table, which represents its composition in the different stages, as deduced from a mean obtained from twelve cases.\n\tCold Stage.\tHot Stage.\tSweating Stage.\nSpecific gra-\t1017-330\t1020-304\t1022-820\nvity\t-J\t\t\t\nWater\t967-520\t964-680\t961 -845\nUrea\t9-845\t9-015\t7-624\nUric acid Salts and \"j\t0-660\t0-980\t1-029\norganic > matter - J\t21-975\t25-325\t29-502\nNotwithstanding the variations from the natural standard shown by the above table, it often happens that the urine in agues differs but little from that of health in every stage of the disease.\nCholera.\nIn this disease the urine is often altogether suppressed. When it can be collected in any quantity, its specific gravity is generally below the natural standard, and it has only a feeble acid reaction. Albumen is very often to be found it it. The urea is below the standard of health. Vogel states that the urine, in a case of this disease which he examined, was entirely wanting in the salts of lime and magnesia, and that the chloride of sodium was deficient. The sulphates, however, were in larger proportion than in health. Albumen and biliary colouring matter could be detected by the appropriate tests.\n945-4\u00ab\n8-60\n0-60\n27-50\n7-40","page":1292},{"file":"p1293.txt","language":"en","ocr_en":"URINE.\n1293\nRheumatism.\nIn this disease the urine shows the usual appearances of the inflammatory type, according to Becquerel. Oxalate of lime not un-frequently exists as a deposit.\nPhthisis.\nIn this disease the principal feature observed in the urine is the increase in the quantity of uric acid. One analysis gave as much as 2'40 of this acid in 1000 parts of urine.\nStruma.\nIn struma, generally speaking, the urine is deficient in urea and uric acid. The phosphates are often excreted in excess, and there is a tendency to the deposit of oxalate of lime. In mollities ossium and rachitis the earthy phosphates are excreted in very large quantity, the alkaline salts are increased, and the urea and uric acid diminished in proportion. The analyses which showed the above results were made on the urine of children, which always contains less urea and salts than that of adults.\nThe following is an analysis, by Marchand, of the urine of a child suffering from mollities\nossium. It was acid.\nWater........................... 938-2\nUrea..............................27'3\nUric acid -\t0\"9\nLactic acid and lactates -\t- 14 2\nPhosphates of lime and magnesia 5\u20187 Other constituents (loss) -\t- 13-7\nDiabetes Mellitus.\nThe urine in this disease contains a sugar which may be regarded as identical with sugar of grapes. It is generally of very high specific gravity, varying from the highest specific gravity observed in health to 1055 or even 1060.\nSch\u00f6nlein has an opinion that in the first stages of diabetes there is albumen in the urine, and that this becomes replaced by sugar. This opinion I scarcely can believe correct. The fact, indeed, could not well have escaped my notice, my attention having been particularly directed to the study of albuminaria for some years past. The experiments of Kant have shown that urea is generally excreted in diabetes mellitus to the same amount as in health in the twenty-four hours. During the progress of the disease I have several times observed the whole of the sugar suddenly disappear from the urine, and its place supplied by an enormous excretion of urea. I at first was inclined to regard this as a favourable indication, but experience has not confirmed that belief. Uric acid is |not uncommonly present in considerable quantity, and this I believe to be a favourable indication in diabetes. Simon has shown that the absolute quantity of urea excreted in twenty-four hours is occasionally diminished ; but the general rule is that the quantity approaches that of health. Caseous matter is sometimes found in diabetic urine, and, when present, it excites rapid fermentation immediately after the urine is voided.\nBouchardat has described a form of sugar which occasionally exists in diabetes, which is insipid, but which corresponds in every other respect with the sweet sugar. Simon says he once met with it.\nLehmann, Ambrosiani, M\u00fcller, and Simon have observed the presence of hippuric acid in diabetic urine.\nDiabetes Insipidus.\nIn this disease the urine contains an excess of water, and varies in specific gravity from 1001 to 1006. The urea, if regarded in proportion to the other solid matters excreted, is excessive in quantity, but the proportion discharged during the twenty-four hours is generally far below that of health.\nThis excessive discharge of urea, as compared with the other solids, may be accompanied by a less discharge of water than that which is generally found to accompany it. Then the urine attains a specific gravity approaching that of health, and sometimes even exceeding it. Chemically, these two conditions so nearly approach, as scarcely to need division. Pathologically considered, however, the latter is the more serious form of disease, and is believed by some to be not an unfrequent forerunner of diabetes mellitus.\nDiabetes Chylosus.\nThis disease is characterised by the discharge of chyle in the urine. It is quite milky in appearance. A specimen I examined some few years ago yielded the following results :\nSpecific gravity 1021.\nAcid in slight degree only.\nMilkiness, not changed from subsidence by standing.\nAgitated with ether the urine was cleared, and the ethereal solution, which then floated above, contained a fat, yielding an alkaline ash on incineration. This fat was not saponifiable by boiling with a solution of potassa. The urine cleared from the fat coagulated by boiling, and also on the addition of nitric acid.\nJaundice.\nThe elements of bile exist in the urine in cases of jaundice. Simon has published the following result, obtained from the urine of a female, aged twenty, suffering from inflammatory icterus.\nThe urine was brownish red, and of specific gravity 1020, and very acid.\nWater -\t-\t-\t-\nUrea -\nUric acid, with biliph\u00e6in Alcoholic extractive Spirituous ditto Aqueous ditto, with mucus and bile pigment -Biliary resin -\t-\t-\nBiliverdin -Earthy phosphates -Chloride of sodium and lactate of soda -\nAlkaline phosphates and sulphates, with traces of chloride of sodium -\n954-50\n12-34\n2-\t90\n4-\t35 529\n5-\t14\n1-\t45 1-08\n3-\t14\n2-\t61\n3-90","page":1293},{"file":"p1294.txt","language":"en","ocr_en":"1294\nVARIETIES OF MANKIND.\nThe urea is here below the normal standard ; the uric acid increased.\nScherer examined urine obtained from a person labouring under long-continued icterus, dependent on chronic inflammation of the hepatic structure. On emission this urine was clear, yellow, and perfectly neutral : it subsequently became acid, and deposited uric acid and bile pigment. This acidity Scherer believes was owing to the development of lactic acid.\nThe specific gravity of the specimen was 1018 ; 1000 parts yielded A3 of urea only, and as much as T8 of uric acid. Silica was also found in this urine.\nUrine of Pregnancy.\nThe urine of pregnant women often contains a peculiar substance, to which the name of kystein has been given. It appears as a white scum when the urine has stood some hours. I have frequently found this substance in urine at the third and fourth months of gestation, and have no doubt that its appearance is closely connected with the phenomenon of the secretion of milk. In several instances I succeeded in detecting distinct milk globules in such urine.\nForeign Substances in the Urine.\nMedicines, and substances taken for food, are occasionally found in the urine. Some of these, however, undergo changes in the organism before they are excreted by the kidneys.\nSimon has classified these bodies ; and I shall here enumerate them according to his arrangement.\nInorganic non-mctallic bodies. \u2014 Iodine, bromine, chlorine, sulphur *, iodide of potassium, alkaline borates, silicates, chlorates, and carbonates, chloride of barium, ferridcyanide of potassium, sulphocyanide of potassium. The ferridcyanide was converted, however, into the ferrocyanide in the system.\nMetallic substances. \u2014 Arsenic, antimony, iron, nickel, \u2019gold, silver, tin, lead, bismuth, copper, and manganese. I have sought in vain for mercury in the urine. Lehmann and L\u2019H\u00e9ritier have also failed to find it where it has been largely exhibited. Several chemists, however, declare they have detected it.\nInorganic acids. \u2014 Nitricf, hydrochloric, and sulphuric.\nOrganic acids* \u2014 Oxalic, citric, malic, tartaric, succinic, gallic, and acetic.\nPereira has succeeded in detecting meconic acid in the urine of animals poisoned by opium.\nVegetable bases. \u2014Quina, morphia.\nIndifferent organic substances. \u2014 Colouring matters of indigo, gamboge, rhubarb, red beetroot, madder, logwood, mulberries, black cherries ; odorous principles of valerian,\n* This, if exhibited in combination in sulphurets, is excreted as sulphate of the base.\n\u2022j- Dr. Bence Jones believes that nitric acid is commonly present in healthy urine, and appears as the result of the oxidation of nitrogenised food.\nassafcetida, garlic, castoreum, saffron, turpentine.\nLiebig and Wohler both state that alcohol cannot be detected in the urine. Percy, however, has proved that it can. Dr. Wright has corroborated Percy\u2019s experiments, and obtained alcohol by the same plan of analysis.\nLehmann and others sought unsuccessfully for the following substances in the urine : viz., salicin, phloridzin, caflein, theobromin, as-paragin, and amygdalin. These substances probably undergo changes in the organism.\nLehmann has shown that salicin becomes converted into salicylous acid ; this was taken up by ether with the oxide of omichmyle. The addition of nitrate of iron produced the fine violet colour characteristic of salicylous acid. Hippuric acid and oxalate of lime were also produced.\nPhloridzin is converted into oxalic and hippuric acids during its passage through the organism, according to Lehmann.\nFor tbe Bibliography reference is 'made to the works of Berzelius, Prout, Simon, Liebig, Dumas, Lehmann, on Animal Chemistry, and to those quoted in the foot notes.\n(G. Owen Rees.')\nVARIETIES OF MANKIND.\u2014Under this head it is intended to give a general account of the distinctive characters, \u2014 structural, physiological, and psychological \u2014 of the principal Races of Men ; and to inquire into the nature and degree of their mutual affinity. Before entering upon these subjects, however, it will be desirable, in the first place, to set forth the most important characters by which Man, under whatever form, is distinguished from the Mammalia which approach most nearly to him ; and, secondly, to lay a foundation in the recognised principles of natural history and physiology, for a true appreciation of the characters which serve to distinguish species from each other, as contrasted with those which may be presented by varieties, whose original stock is known, or believed, to have been identical.\nI. Distinctive Characteristics of Man.\nBy Cuvier and nearly all modern zoologists, the various races of mankind are included under one genus, Homo ; and this genus takes rank, in the classification of Mammalia, as a distinct order, Biman a, of which it is the sole representative. Of all the characters which distinguish Man from the inferior Mammalia, the possession of two hands is doubtless the most easily recognised, and at the same time the most intimately related to the general organisation of the body; and there is none, therefore, which could be more appropriately selected as the basis of a distinctive designation for this order. At first sight it might be considered that the possession of only two hands, whilst Apes and Monkeys and their allies are designated as possessing four, is a character of inferiority ; but such is not really the case ; for none","page":1294},{"file":"p1295.txt","language":"en","ocr_en":"1295\nVARIETIES OF MANKIND.\nof these four hands are adapted to the variety of actions of which those of man are capable, and they are all in some degree required for support ; so that whilst in the higher forms of the Quadrumanous order, the extremities present a certain approximation in structure to those of man, in the lower they gradually assimilate to the ordinary quadrupedal type. \u201c That,\u201d says Cuvier, \u201c which constitutes the hand, properly so called, is the faculty of opposing the thumb to the other fingers, so as to seize upon the most minute objects ; a faculty which is carried to its highest degree of perfection in Man, in whom the whole anterior extremity is free, and can be employed in prehension.\u201d The peculiar prehensile power possessed by man is chiefly dependent upon the size and power of the thumb ; which is more developed in Man than it is in the highest apes. The thumb of the human hand can be brought into exact opposition to the extremities of all the fingers, whether singly or in combination ; whilst in those Quadrumana which most nearly approach man, the thumb is so short, and the fingers so much elongated, that their tips can scarcely be brought into opposition ; and the thumb and fingers are so weak, that they can never be opposed to each other with any degree of force. Hence, although admirably adapted for clinging round bodies of a certain size, such as the small branches of trees, &c., the extremities of the Quadrumana can neither seize very minute objects with such precision, nor support large ones with such firmness, as are essential to the dexterous performance of a variety of operations, for which the hand of Man is admirably adapted. There is much truth, then, in Sir C. Bell's remark, that \u201cwe ought to define the hand as belonging exclusively to man.\u201d There is in him, what we observe in none of the Mammalia which approach him in other respects, a complete distinction in the functional character of the anterior and posterior extremities ; the former being adapted for prehension alone, and the latter for support and progression alone; and thus each function is performed in a much higher degree of perfection, than it can be when two such opposite purposes have to be united. For not only is the hand of man a much more perfect prehensile instrument than that of the orang or chimpanzee, but his foot is a much more perfect organ of support and progression than theirs, being adapted to maintain his body in an erect position, alike during rest and whilst in motion, \u2014 an attitude which even the most anthropoid apes can only sustain for a short time, and with an obvious effort. The arm of the higher apes has as wide a range of motion as that of man, so far as its articulation is concerned ; but it is only when the animal is in the erect attitude, that the limb can have free play. Thus the structure of the whole frame must be conformable to that of the hand, in the way that we find it to be in man, in order that this organ may be advantageously applied to the purposes which it is\nadapted to perform. But it cannot be said with truth (as some have maintained) that Man owes his superiority to his hand alone ; for without the mind by which it is directed, and the senses by which its operations are guided, it would be a comparatively valueless instrument. Man\u2019s elevated position is due to the superiority of his mind and of its material instruments conjointly ; for if destitute of either, the human race must be speedily extinguished altogether, or reduced to a very subordinate grade of existence.\nThe next series of characters to be considered, are those by which man is adapted to the erect attitude. On examining his cranium, we remark that the occipital condyles are so placed, that a perpendicular dropped from the centre of gravity of the head would nearly fall between them, so as to be within the base on which it rests upon the spinal column. The foramen magnum is not placed in the centre of the skull, but just behind it ; so that the greater specific gravity of the posterior part of the head, which is entirely filled with solid matter, is compensated by the greater length of the anterior part, which contains many cavities. There is, indeed, a little overcompensation, which gives a slight preponderance to the front of the head, so that it drops forwards and downwards, when all the muscles are relaxed ; but the muscles which are attached to the occiput are larger and far more numerous than those in front of the condyles, so that they are evidently intended to counteract this disposition ; and we find, accordingly, that we can keep up the head for a whole day, with so slight and involuntary effort, that no fatigue is produced by it. Moreover, the plane of the foramen magnum, and the surfaces of the condyles, have a nearly horizontal direction when the head is upright ; and thus the weight of the skull is laid vertically upon the top of the vertebral column. If these arrangements be compared with those which prevail in other Mammalia, it will be found that the foramen and condyles are placed in the latter much nearer the back of the head, and that their plane is more oblique. Thus, whilst the foramen magnum is situated, in Man, just behind the centre of the base of the skull, it is found in the Chimpanzee and Orang to occupy the middle of the posterior third ; and as we descend through the scale of Mammalia, we observe that it gradually approaches the back of the skull, and at last comes nearly into the line of its longest diameter, as we see in the Horse. So the angle of inclination which the condyles make with the horizontal is very small in Man, but rises in the Orang to 37\u00b0 ; whilst in the Horse their plane is vertical, making the angle 90\u00b0. If, therefore, the natural posture of man had been horizontal, the plane of his condyles would be brought, like that of the horse, into the vertical position ; and the head, instead of being nearly balanced upon the summit of the vertebral column, would hang at the end of the neck, so that its whole weight would have to be supported by some","page":1295},{"file":"p1296.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1296\nexternal and constantly-acting power. But for this there is neither in the skeleton, the ligamentous apparatus, nor the muscular system of Man, any adequate provision ; so that in any other than the vertical position, his head, which is relatively heavier than that of most Mammalia, would be supported with more difficulty and effort than it is in any other animal.\nThe position of the face immediately beneath the anterior portion of the cranial cavity, so that its front is nearly in the same plane as the forehead, is peculiarly characteristic of Man ; for the crania of the Chimpanzee and Orang, which approach most nearly to that of man, are entirely posterior to, not above, the face (see figs. 800\u2014802.). It should be remarked that in the young ape, there is a much greater resemblance to man in this respect, than there is in the adult ; for it is at the time of the second dentition, that the muzzle of the ape acquires its peculiar elongation and consequent projection in front of the forehead ; and the whole cast of the features is altered at the same time, so as to approximate much more closely to that of the lower Quadrumana than would have been thought likely from the inspection of the young animal only. This projection of the muzzle, taken in connection with the obliquity of the condyles, is another evidence of want of adaptation to the erect posture; whilst the want of prominence in the face of Man shows that none but the erect position can be natural to him. For supposing that with a head formed and situated as at present, he were to move upon all fours, his face would be brought into a plane parallel with the ground ; so that as painful an effort would be required to examine with the eyes an object placed in front of the body, as is now necessary to keep the eyes fixed on the zenith ; the nose would then be almost incapacitated for receiving any other odorous emanations, than those proceeding from the earth or from the body itself; and the mouth could not touch the ground, without bringing the forehead and chin also in contact with it. The obliquity of the condyles in the Quadrumana enables them without much difficulty to adapt the inclination of their heads either to the horizontal or to the erect posture ; but the natural position, in the highest among them, is unquestionably one in which the spinal column is inclined, the body being partially thrown forwards, so as to rest upon the anterior extremities ; and in this position, the face is directed forwards without any effort.\nThe vertebral column in Man, although not absolutely straight, has its curves so arranged, that when the body is in the erect posture, a vertical line from its summit would fall exactly on the centre of its base. It increases considerably in size in the lumbar region, so as to be altogether somewhat pyramidal in its form. The lumbar portion, in the chimpanzee and orang, is by no means of the same proportional strength, and contains but four vertebrae instead of five. The processes for\nthe attachment of the dorso-spinal muscles to this part, are peculiarly large and strong in man ; and this arrangement is obviously adapted to overcome the tendency, which the weight of the trunk in front of the column would have to draw it forwards and downwards. On the other hand, the spinous processes of the cervical and dorsal vertebrae, which in other Mammalia are large and strong, for the attachment of the ligaments and muscles that support the head, have comparatively little prominence in man, whose head is balanced upon the summit of the column.\nThe base of the human vertebral column is placed on a sacrum of greater proportional breadth than that of any other animal ; this sacrum is fixed between two widely expanded ilia ; and the whole pelvis is thus peculiarly broad. In this manner the femoral articulations are thrown very far apart, so as to give a wide basis of support ; and by the oblique direction of the axis of the pelvis, the weight of the body is transmitted almost vertically from the top of the sacrum to the upper part of the thigh bones. The pelvis of the anthropoid apes is very differently constructed. That of the orang, for example, is much longer and narrower ; its al\u00e6 extend upwards rather than outwards, so that the space between the lowest ribs and the crest of the iliac bones is much less than in man ; their surfaces are nearly parallel to that of the sacrum, which is itself longer and narrower ; and the axis of the pelvis is nearly parallel with that of the vertebral column. The position of the human femur, in which its head is most securely retained in its deep acetabulum, is that which it has when supporting the body in the erect attitude ; in the chimpanzee and orang, its analogous position is at an oblique angle to the long axis of the pelvis, so that the body leans forwards in front of it ; in many of the four-footed Mammalia, as the elephant, it makes a right angle with the vertebral column ; and in several others, as the horse, ox, &c., the angle which it makes with the axis of the pelvis and vertebral column is acute. In this respect, then, the skeleton of man presents an adaptation to the erect posture, which is exhibited by that of no other mammal.\nThe lower extremities of Man are remarkable for their length, which is proportionally greater than that which we find in any other mammalia, excepting the kangaroo and a few other leaping animals. The chief difference in their proportional length, between man and the semi-erect apes, is seen in the thigh ; and from the relative length of this part in him, and the comparative shortness of his anterior extremities, it happens that the hands of Man, when he is standing erect, only reach to the middle of his thighs, whilst in the Chimpanzee they hang on a level with the knees, and in the Orang they descend to the ancles. The human femur is distinguished by its form and position, as well as by its length. The obliquity of its neck still further increases the","page":1296},{"file":"p1297.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1297\nbreadth of the hips ; whilst it causes the lower extremities of the femora to be somewhat obliquely directed towards each other, so that the knees are brought more nearly into the line of the axis of the body. This arrangement is of the greatest importance in facilitating the purely biped progression of Man, in which the entire weight of the body must be alternately supported upon each limb ; for if the knees had been kept further apart, the whole body must have been swung from side to side at each step, so as to bring the centre of gravity over each tibia, \u2014 as is seen, to a certain extent, in the female sex, whose walk, owing to the greater breadth of the pelvis, and the separation between the knees, is less steady than that of the male. There is a very marked contrast between the knee-joint of Man, and that of even the highest Apes. In the former the opposed extremities of the femur and tibia are so expanded as to present a very broad articulating surface ; and the internal condyle of the femur being the longer of the two, they'are in the same horizontal plane in the usual oblique position of that bone; so that by this arrangement the whole weight of the body, in its erect posture, falls vertically on the head of the tibia, when the joint is in the firmest position in which it can be placed. The knee-joint of the Orang, on the other hand, is comparatively deficient in extent of articulating surface ; and its whole conformation indicates that it is not intended to serve as more than a partial support. The human foot is, in proportion to the size of the whole body, larger, broader, and stronger than that of any other existing mammal, save the kangaroo. Its plane is directed at right angles to that of the leg ; and its sole is concave, so that the whole weight of the body falls on the summit of an arch, of which the os calcis and the metatarsal bones form the two points of support. This arched form of the foot, and the habitual contact of the os calcis with the ground, are peculiar to Man alone. All the apes have the os calcis small, straight, and more or less raised from the ground, which they touch, when standing erect, with the outer side of the foot only ; whilst in animals more remote from man, the os calcis is brought still more into the line of the tibia ; and the foot being more elongated and narrowed, only the extremities of the toes come in contact with the ground. Hence Man is the only species of mammal which can stand on one leg. The points in which the feet of the anthropoid apes differ from his, all assimilate them to the manual type of conformation, and enable them to serve as more efficient prehensile organs, whilst they diminish their capacity to sustain the weight of the body when it simply rests upon them.\nThere is a considerable difference in the form of the trunk, between Man and most other mammalia ; for his thorax is expanded laterally, and flattened in front, so as to prevent the centre of gravity from being carried too far forwards. His sternum is short and\nVOL. iv.\nbroad compared with that of quadrupeds generally ; and there is consequently a considerable space between its Tower extremity and the symphysis pubis, occupied solely by muscular parts, which would be quite inadequate to sustain the weight of the viscera, if the habitual position of the trunk had been horizontal. In these particulars, however, the most anthropoid Apes agree with Man.\nReturning now to the skull for a more minute examination, and referring to the article Quadrumana for an account of the principal differences presented between the skulls of the ordinary Chimpanzee and Orang, and that of Man, we shall take as our standard of comparison the recently-discovered species of Chimpanzee, designated as the Troglodytes gorilla, whose cranium is considered by Prof. Owen to approach in some respects more nearly to that of man, than do either of the preceding. This species differs from the T. niger (Simia troglodytes, Vrolik) by its considerably greater dimensions, by the greater prominence of the supra-orbital ridges, the enormous development of the crest, which occupies the place of the sagittal suture, the greater strength of the zygomatic arches, and the greater size of the temporal fossa. For the more minute, but definite characters, on which the specific distinction is grounded, the description by Prof. Owen must be consulted.* The slightest glance at figs. 800, 801, 802. is sufficient to show how strongly marked are the features by which the skull of this Chimpanzee differs from that of even the most degraded of the Human family ; but it will be advantageous to subjoin Prof. Owen\u2019s enumeration of the chief differences which are revealed by a careful anatomical survey. These are : \u2014\n\u201c 1. The smaller proportional size of the cranium.\n\u201c 2. The more backward position of the foramen magnum, and its more oblique plane in relation to that of the base of the skull.\n\u201c 3. The smaller relative size, and more backward position, of the Occipital condyles.\n\u201c 4. The longer basi-occipital, and broader, flatter, and lower supra-occipital.\n\u201c 5. The longer basisphenoid, and shorter alisphenoids.\n\u201c 6. The smaller size of the coalesced pa-rietals, and their separation from the alisphenoids.\n\u201c 7. The conversion of a greater part of the outer surface of the parietals into concavities or depressions for the lodgment ot the temporal muscles, by reason of the bony crest developed from the line of the obliterated sagittal suture, and of the lambdoidal crest.\n\u201c 8. The larger proportion of this crest and of the squamosal plate developed from the mastoid, and the smaller size of the proper mastoid processes.\n\u201c 9. The smaller size of the vaginal and styliform processes, and the absence of the\n* Transactions of the Zoological Society, vol. Hi. p. 392. et seq.\n4 o","page":1297},{"file":"p1298.txt","language":"en","ocr_en":"1298\tVARIETIES\nstyloid process, arising from the non-anchj losis of the stylo-hyal bone.\nFig. 800.\nFront, side, and basal views of the skull of the Troglodytes gorilla. (After Owen.)\n\u201c 10. The larger post-glenoid process, and the longer auditory process (tympanic bone), with their relative position, one behind, but not below, the other.\nOF MANKIND.\n\u201c 11. The position of the stronger zygomata opposite the middle third of the basis cranii.\n\u201c12. The prominent supra-orbital ridge.\n\u201c 13. The longer nasal bones, anchylosed together, and flattened at their lower half.\n\u201c 14. The greater proportional size, and greater prominence of the upper and lower jaws.\n\u201c 15. The longer osseous palate, and the median emargination of its posterior border.\n\u201c 16. The parallelism of the alveoli of the molars and canine of one side, with those of the other.\n\u201c17. The diastema, or vacant place, in front of the socket of the canine in the upper jaw, and behind that socket in the lower jaw.\n\u201c 18. The larger and more produced pre-maxillaries, the persistence of more or less of their sutures, showing the intervention of their upper extremities between the nasal and maxillary bones.\n\u201c 19. The minor extent of connection of the lachrymal with the * pars plana \u2019 of the \u00e6thmoid, or their separation by the junction of the orbital plate of the maxillary with that of the frontal behind the lachrymal.\n\u201c 20. The depth of the olfactory fossa, and the absence or rudimental state of the crista galli.\n\u201c21. The squamosal, lambdoidal, alisphe-noidal and pterygoid air-cells.\n\u201c 22. The more prominent cusps of the molar teeth.\n\u201c 23. The larger relative size, and more complex grinding surface of the last molar tooth in both jaws.\n\u201c 24. The larger relative size of the premolars, especially of the first.\n\u201c 25. The more complex implantation of the premolars by three roots, two external and one internal.\n\u201c 26. The much larger and longer canines.\n\u201c 27. The sexual distinction in the development of these teeth.\n\u201c 28. The more sloping position of the crowns of the incisors.\n\u201c 29. The broader and higher ascending ramus of the lower jaw.\n\u201c 30. The total absence of the prominence of the symphysis forming the chin.\n\u201c In the form of the premaxillaries, and the earlier obliteration of their sutures,\u201d Prof. Owen continues, \u201c the smaller chimpanzee more nearly resembles man than the great gorilla does ; it seems also to deviate less through the minor development of the canine teeth, and of the parietal and sagittal crests ; but it has been shown, in the comparison of the skulls of Troglodytes gorilla and T. niger, that the latter departs in more numerous and important particulars further from the human type.\u201d\nNow, of the foregoing characters, some of those which constitute the most striking features in the cranium of the Chimpanzee, are those which must be admitted from analogy to be liable to variation under the influence","page":1298},{"file":"p1299.txt","language":"en","ocr_en":"1299\nVARIETIES OF MANKIND.\nof a change of habits, provided such change could be induced. Thus we find that in dogs, the general form of the cranium, and the sagittal crest, undergo considerable modification ; the brain acquiring a very large size, in several of the domesticated races, at an early period of life ; and the parietal bones being expanded over it so as to form a smooth dome, instead of rising up to meet in a vertical ridge. But the prominence of the supraorbital ridge does not seem to be in any way connected with the relative development of the cerebrum and of the muscular system ; and as Prof. Owen remarks, \u201c We have no grounds from observation or experiment to believe the absence or the presence of a prominent supra-orbital ridge to be a modifiable character, or one to be gained or lost through the operation of external causes, inducing particular habits through successive generations of a species. It may be concluded, therefore, that such feeble indication of the supra-orbital ridge, aided by the expansion of the frontal sinuses, as exists in man, is as much a specific peculiarity of the human skull, in the present comparison, as the exaggeration or suppression of this ridge is respectively characteristic of the chimpanzees and orangs.\u201d The same may be said of nearly all the other distinctive characters which have been so minutely enumerated ; for they serve to distinguish the great chimpanzee from all the varieties of the human race, \u2014 from the most degraded African, as well as from the most elevated European. The shape, size, and construction of the \u201c premaxillary \u201d bones (\u201c inter-maxillaries \u201d of the ordinary nomenclature) are peculiarly distinctive ; for they not only differ from those of Man in their vastly greater proportional size, their greater prominence, and the longer persistence of their sutures, but also in their upward extension around the nostrils, so that they completely exclude the maxillary bones frotn their borders, and form the bases of support for the nasal bones (fig. 800.) It is to be remembered that the apparent deficiency of the inter-maxillary bone in the human subject is the result of its early coalescence with the maxillary ; and that this coalescence may be prevented by an arrest of development, so that the two bones remain permanently distinct.*\nHaving dwelt thus fully on the distinctive features of the Osteology of Man, it will be sufficient to pass over his other peculiarities of conformation more cursorily, referring to the article Quadrumana for more minute details. In his Myology, the most characteristic difference is the much greater development of those muscles of the trunk and limbs, which contribute to the maintenance of the erect posture. Thus the gastrocnemii and the other muscles which tend to keep the leg erect upon the foot, form a much\n* A very definite account of the early embryonic state of the intermaxillary bone, is given by Dr. Leidy in the Proceedings of the Academy of the Natural Sciences of Philadelphia for 1848.\nmore prominent \u201ccalf\u201d than is seen in any other animal. So, again, the extensors of the leg upon the thigh are much more powerful than the flexors ; a character which is peculiar to man. The glutaei, by which the pelvis is kept erect upon the thigh, are of far greater size than is elsewhere seen. The superior power of the muscles tending to draw the head and spine backwards, has been already referred to. Among the differences in the attachment of individual muscles, we may notice that the flexor longus pollicis pedis proceeds in man to the great toe alone, on which the weight of the body is often supported ; whilst it is attached in the chimpanzee and orang to the three middle toes. The latissi-mus dorsi of man is destitute of that prolongation attached to the olecranon, which is found in most of the lower Mammalia, and which exists even in the chimpanzee, probably giving assistance in its climbing movements. The larger size of the muscles of the thumb is, as might be expected, a characteristic of the hand of man, though the number of muscles by which that digit is moved is the same in the chimpanzee as in the human subject. The existence of the extensor digiti indicis, as a distinct muscle, however, is peculiar to man.\nThe visceral apparatus of Man presents very few characteristic peculiarities, by which it can be distinguished from that of the higher Quadrumana ; among the most remarkable is the absence of the laryngeal pouches, which exist even in the chimpanzee and orang-outan, as dilatations of the laryngeal ventricles. Of the anatomy of the last-named animals in their adult condition, however, we know as yet too little, to enable its resemblance to that of man to be confidently pronounced upon.\nThe conformation of the brain of Man does not differ so much from that of the chimpanzee and orang, as the superiority of his mental endowments might have led us to anticipate. The following are the principal differences which it seems to present:\u2014 1. The mass of the entire brain is considerably larger in proportion to that of the body, and in proportion also to the diameter of the nerves which are connected with it. 2. In the external configuration of the cerebrum, we notice that the 'posterior lobes are more developed, so as to project further beyond the cerebellum than they do in any of the quadrumana ; the convolutions are more numerous, and the sulci are deeper. 3. On examining the internal structure, it is found that the peripheral layer of grey matter is thicker, the corpus callosum extends further backwards, and the posterior cornua of the lateral ventricles are relatively longer and larger than they are in any Quadrumana. 4. The cerebellum, also, is proportionally larger. \u2014 The great size of the cranial portion of the skull in Man, as compared with the facial, produces a marked difference between his facial angle, and that of even the highest Quadrumana. According to Camper, who first\n4 o 2","page":1299},{"file":"p1300.txt","language":"en","ocr_en":"1300\nVARIETIES OF MANKIND.\napplied this method of measurement, the facial angle of the average of European skulls is 80\u00b0, whilst in the ideal heads of the Grecian gods it is increased to 90\u00b0 ; on the other hand, in the skull of a Kalmuck he found it to be 75\u00b0, and in that of a Negro only 70\u00b0 ; and applying the same system of measurement to the skulls of Apes, he found them to range from 6d\u00b0 to 60\u00b0. But these last measurements were all taken from young skulls, in which the forward extension of the jaws, which takes place on the second dentition, had not yet occurred. In the adult Chimpanzee, as we learn from the measurements of Prof. Owen, the facial angle is no more than 35\u00b0, and in the adult Orang only 30\u00b0; so that instead of the Negro being nearer to the Ape than to the European, as Camper\u2019s estimate would make him, the interval between the most degraded human races and the most elevated Quadrumana is vastly greater than between the highest and lowest forms of humanity. It must be borne in mind that the facial angle is so much affected by the degree of prominence of the jaws, that it can never afford any certain information concerning the elevation of the forehead and the capacity of the cranium ; all that it can in any degree serve to indicate, is the relative proportion between the facial and cranial parts of the skull. The small size of the face of Man, compared with that of the cranium, is an indication that in him the senses are subordinated to the intelligence. Accordingly we find that he is surpassed by many of the lower animals in acuteness of sensibility to light, sound, &c. ; but he stands preeminent in the power of comparing and judging of his sensations, and of drawing conclusions from them as to their objective sources. Moreover, although none of his senses are very acute in his natural state, they are all moderately so ; and they are capable of being wonderfully improved by practice, when circumstances strongly call for their exercise. This seems especially the case with the tactile sense (see article Touch, p. 1177), of which man can make greater use than any other animal, in consequence of the entire freedom of his anterior extremities, although there are many which surpass him in their power of appreciating certain classes of tactile impressions. So, again, Man\u2019s nervo-muscular power is inferior to that of most other animals of his size ; the full grown Orang, for example, surpasses him both in strength and agility ; and the larger Chimpanzee, according to the statements of the negroes who have encountered it, is far more than a match for any single man, and is almost certain to destroy any human opponent when once within his grasp. The absence of any natural weapons of offence, and of direct means of defence, are remarkable characteristics of Man, and distinguish him not only from the lower Mammalia, but also from the most anthropoid Apes ; in which it is obvious (both from their habits and general organisation) that the enormous canines have no relation to a car-\nnivorous regimen, but are instruments of warfare. On those animals to which nature has denied weapons of attack, she has bestowed the means either of passive defence, of concealment, or of flight ; in each of which Man is deficient. Yet, by his superior reason, he has not only been enabled to resist the attacks of other animals, but even to bring them into subjection to himself. His intellect can scarcely suggest the mechanism which his hands cannot frame ; and he has devised and constructed arms more powerful than those which any other creature wields, and defences so secure as to defy the assaults of all but his fellow men.\nThe power of adaptation to varieties in external condition, which renders Man to a great extent independent of them, is one of the most remarkable peculiarities of his economy. He is capable of sustaining the lowest as well as the highest extremes of temperature and of atmospheric pressure. In the former of these particulars he is strikingly contrasted with the anthropoid apes ; the Chimpanzee being restricted to the hottest parts of Africa, and the Orang outan to the tropical portions of the Indian Archipelago*1; and neither of these animals being capable of living in temperate climates without the assistance of artificial heat, even with the aid of which they have not hitherto survived their second dentition. So, again, although Man\u2019s diet seems naturally of a mixed character, he can support himself in health and strength either on an exclusively vegetable diet, or, under particular circumstances, on an almost exclusively animal diet. It is in thus adapting himself to the conditions of his existence, in providing himself with food, shelter, weapons of attack and defence, &c., that man\u2019s intellectual powers are first called into active operation ; and when thus aroused, their development has no assignable limit. The will, guided by the intelligence, and acted on by the desires and emotions, takes the place in man of the instinctive propensities which are the usual springs of action in the lower animals ; and although, among the most elevated of these, the intelligent will is called into exercise to a certain extent, yet it never acquires among them, the dominance which it possesses in man. The capacity for intellectual progress is a remarkable peculiarity of man\u2019s psychical nature. The instinctive habits of the lower animals are limited, and peculiar to each species, and have immediate reference to their bodily wants. Where a particular adaptation of means to ends, of actions to circumstances, is made by an individual (as is frequently the case, when some amount of intelligence or rationality exists), the rest do not seem to profit by it ; so that, although (as will be shown hereafter) the instincts of particular animals may be modified by the training of man, or by the education of circumstances, so as to show themselves after a few generations under new forms, no elevation in intelligence appears ever to take place spontaneously, no psychical im-","page":1300},{"file":"p1301.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1301\nprovement is manifested in the species at large. One of the most important aids in the use and development of the human mind, is the capacity for articulate speech ; of which, so far as we know, man is the only animal in possession. There is no doubt that many other species have certain powers of communication between individuals; but these are probably very limited, and of a kind more allied to the \u201c language of signs,\u201d than to a proper verbal language. In fact it is obvious that the use of a language composed of a cer-certain number of distinct sounds, combined into words in a multitude of different modes, requires a certain degree of that power of abstraction and generalisation, in which (as elsewhere remarked*) it appears that the lower animals are altogether deficient. The correspondence between the psychical endowments of the Chimpanzee and those of the Human infant before it begins to speak, is extremely close ; and those who have perused the interesting narrative given by Dr. Howe, of his successful training of Laura Bridgeman, will remember how marked was the improvement in her mental condition, from the time when she first apprehended the idea that she could give such expression to her thoughts, feelings and desires, as should secure their being comprehended by others.\nNow, this capacity for progress is connected with another element in Man\u2019s nature, which it is difficult to isolate and define, but which interpenetrates and blends with his whole psychical character. \u201c The soul,\u201d it has been remarked, \u201cis that side of our nature which is in relation with the infinite and it is the existence of this relation, in whatever way we may describe it, which seems to constitute the most distinctive peculiarity of man. It is in the desire for an improvement in his condition, occasioned by an aspiration after something nobler and purer, that the mainspring of human progress may be said to lie; among the lowest races of mankind, the capacity exists, but the desire seems dormant. When once thoroughly awakened, however, it seems to \u201c grow by what it feeds on ; \u201d and the advance once commenced, little external stimulus is needed; for the desire increases at least as fast as the capacity. In the higher grades of mental development, there is a continual looking upwards, not (as in the lower) towards a more elevated human standard, but at once to something beyond and above man and material nature. This seems the chief source of the tendency to believe in some unseen existence ; which may take various forms, but seems never entirely absent from any race or nation, although, like other innate tendencies, it may be deficient in individuals. Attempts have been made by some travellers to prove that particular nations are destitute of it ; but such assertions have been based only upon a limited acquaintance with their habits of thought, and with their outward observances ; for there are probably none\n* See Art. Instinct, vol. iii. p. 2.\nwho do not possess the idea of some invisible power, external to themselves, whose favour they seek, and whose anger they deprecate, by sacrifice and other ceremonials. It requires a higher mental cultivation than is commonly met with, to conceive of this power as having a spiritual existence ; but wherever the idea of spirituality can be defined, it seems connected with it. The vulgar readiness to believe in demons, ghosts, &c. is only an irregular or depraved manifestation of the same tendency. Closely connected with it, is the desire to participate in this spiritual existence, which has been implanted in the mind of man, and which, developed as it is by the mental cultivation that is almost necessary for the formation of the idea, has been regarded by philosophers in all ages as one of the chief natural arguments for the immortality of the soul. By this immortal soul, Man is connected with that higher order of being, in which Intelligence exists, unrestrained in its exercise by the imperfections of that corporeal mechanism through which it here operates ; and to this state, \u2014 a state of more intimate communion of mind with mind, and of creatures with their Creator, \u2014 he is encouraged to aspire, as the reward of his improvement of the talents here committed to his charge.\nII. Of Species and Varieties, zoologically CONSIDERED.\nThe meaning which the scientific Naturalist attaches to the term Species, is not always defined in the same manner, although the notions which the various definitions are intended to convey, are for the most part essentially similar. Thus a species has been described as \u201c a race of animals or of plants, marked by any peculiar character which has always been constant and undeviating ; \u201d it being obvious, from this definition, which carries us backwards from the present to the past, that the first parents or \u201c protoplasts \u201d of such a race must have been distinguished by the same characters as those by which their descendants are now recognised. But, again, this community of parentage is made by Cuvier to constitute the leading idea conveyed by the term ; for he defines a species to be \u201c the collection of all the beings descended the one from the other, or from common parents ; and of those which bear as close a resemblance to these, as they bear to each other.\u201d \u201cWe are under the necessity,\u201d he elsewhere remarks, \u201c of admitting the existence of certain forms, which have perpetuated themselves from the beginning of the world, without exceeding the limits first prescribed ; all the individuals belonging to one of these forms, constitute what is termed a species.\u201d And M. De Candolle, in like manner, observes that \u201c we unite, under the designation of a species, all those individuals which mutually bear to each other so close a resemblance, as to allow of our supposing that they may have proceeded originally from a single 4 o 3","page":1301},{"file":"p1302.txt","language":"en","ocr_en":"\n1302\tVARIETIES OF MANKIND.\nbeing or a single pair.\u201d Thus it appears that, in one mode or another, the fundamental idea of the term, among all those naturalists who admit the \u201c permanence of species,\u201d connects itself' with the notion of community of descent. This notion, as M. De Candolle admits, is hypothetical, so far at least as its particular applications are concerned ; since in no one case have we the power either of looking back to the epoch of the first production of a species, or of tracing downwards the whole line of descent from any original pair. Still, as it is the only definition which conveys the essence of what naturalists ordinarily mean by species, we shall accept it as the basis of our further inquiries ; and shall now point out the mode, in which it is brought into application in the actual study of natural history.\nWe will suppose the Zoologist to have two new specimens of shells or insects placed before him, or the Botanist to be examining two new specimens of plants. If the conformity between the two is so extremely close, that the differences do not exceed the limits of variation which are commonly seen to prevail in the offspring of a common parentage, he places them in the same species ; because he considers that each may produce a form resembling the other, or may have been produced by it, so that there is no sufficient ground for assigning to the two a distinct ancestry. But supposing that the differences should be more strongly marked, and the naturalist should be tempted to assign different specific names to his two shells, or insects, or plants : in what way is he to diagnose their similarity or diversity of origin ? He forms his judgment, in the first place, by the nature of the characteristic difference ; for this may be of such a kind, that its variability could not be reasonably suspected. Yet this is not a point on which much stress can be laid, when it stands alone ; for although in many groups there are certain characters which present such constancy, that a presumption of specific diversity may be fairly entertained if these should exhibit well-marked differences, yet there are too many exceptions to allow such differences to be unhesitatingly admitted as valid specific characters. They may arise, in fact, from three sets of causes ; namely, differences in age and degree of development, differences in the conditions under which the individuals have existed, and tendency to spontaneous variation inherent in the race. It is necessary, therefore, to exclude each of these possible sources of error, before the specific diversity of our two objects can be established,\n1. It is now universally admitted that the cases are extremely numerous, in which diversities of age have led to the establishment of species which have no existence in nature ; the forms thus distinguished being those of the same species in different grades of development. The more our knowledge of the history of the lower tribes of animals increases, the more is it found that metamor-\nphosis is with them the rule, and not the exception ; so that the cases seem comparatively rare, in which an invertebrated animal at its emersion from the egg possesses the cha- \u2018 racters that serve to distinguish it in its adult condition. And just as the larva, pupa, and imago states of any insect, are all compre- _ hended in a complete account of the species, so 5 must we rank the extraordinary diversities of 1 form presented by the Medus\u0153 or the Balani, in the early period of their lives, as coming within the limits of their specific definitions.\nIt is obvious that this source of fallacy can only be completely avoided, when we have obtained an acquaintance with the whole his- * tory of the life of any individual, from its commencement to its dissolution, and are thus enabled to say positively what are, and what are not, alterations producible by age. Where this knowledge cannot be acquired, the only safe basis on which the naturalist can proceed, is that which is derived from a knowledge of these phenomena as presented in the most nearly allied forms ; and yet this often fails, as in the case of the Astacus fluvia-tilis (river cray-fish), and Gecarcinus (land 1 crab), which undergo no change that can be called a metamorphosis, notwithstanding that in all other Macrourous and Brachyourous Decapods yet observed, a real metamorphosis takes place. Even in the case of extinct species, the history of whose life can never become known to us by any other means than by the preservation of their remains in diff\u00e9rent stages of growth, the careful comparison of a sufficient series of these remains will sometimes establish a strong probability, if not a positive certainty, as to their mutual ; relationship : thus, M. Barrande, of Prague, has succeeded in showing that it is next to certain that no fewer than eighteen forms of Trilobites, which have been described as distinct species and ranked under ten different genera, are really the successive forms of one and the same species ; the differences which they present both in size and conformation being analogous to those that we see in the existing tribes most nearly allied to them, and the whole series constituting one continuous succession. Instances in which new species have been erected among the higher classes of animals, especially among Birds, for the reception of individuals whose differences were only seasonal, have been so frequently recorded, that it is sufficient here to mention them. It is obvious that such errors can only be corrected by a knowledge of the seasonal changes which the species is liable to undergo. Of this source of difficulty in the discrimination of species, we need take no account in our future inquiries ; for although, in the Orang and Chimpanzee, the alteration in the conformation of the cranium which takes place at the period of second dentition, is so very decided, that it formerly gave rise to much confusion, which has only disappeared before a fuller knowledge of the history of these animals, yet no change of such magnitude occurs in Man ; and of the","page":1302},{"file":"p1303.txt","language":"en","ocr_en":"VARIETIES\ndegree' of change which does take place in the several races of mankind, between infancy and old age, there is seldom much difficulty in collecting information.\n2. The influence of external conditions in modifying the conformation both of Plants and Animals, is a question of fundamental importance in the determination of the value of specific characters. In this respect there is a very extraordinary diversity among the several races of living beings, even among those which are most nearly allied to each other ; for whilst some possess such a capacity for variation, that they are easily influenced by changes in external conditions, and can, in consequence, readily adapt themselves to these, to others this capacity seems altogether denied. It is from this circumstance that we find particular species, of plants, as well as of animals, restricted to particular conditions in regard to climate, food, &c., their constitutions not being able to adapt themselves to any considerable change ; whilst others are more widely dispersed, simply because their constitutions can accommodate themselves to alterations in these conditions. Hence a change of food or climate, to which the latter soon become habituated, is fatal to the former. We see this difference well marked in the Feline tribe ; for whilst the greater part of the larger species, such as the lion and tiger, are inhabitants of tropical regions, and cannot endure the winter\u2019s cold, even in the temperate zone, the domestic cat follows man in almost all his wanderings, and can sustain extremes of heat and cold as well as he can himself. This accommodation is effected by a change in the organism itself, of which evident indications are frequently presented, even within the course of a short time: thus, sheep transported from this country to the West Indies soon loose their covering of thick wool, and acquire in the place of it a short, fine hair, shining and smooth, like that of the goat in his best state, so that after a few years the sheep can scarcely be distinguished from the goats, save by their general conformation ; and in this, too, from the usual absence of any considerable accumulation of fat in the bodies of the sheep, there is not nearly so much difference between the two races, as there is in temperate climates.\nThe continued action of the same circumstances for a few generations, gives increased permanence to the new characters of the breed, so that acquired peculiarities of conformation become congenital. Thus, Sir C. Lyell mentions* that some Englishmen engaged in conducting the mining operations of the Real del Monte Company in Mexico, carried out with them some greyhounds of the best breed, to hunt the hares which abound in that country. The great platform, which is the scene of sport, is at an elevation of about 9000 feet above the level of the sea, and the mercury in the barometer stands habitually at the height of about 19 inches.\nOF MANKIND.\t1303\nIt was found that the greyhounds could not support the fatigues of a long chase in this attenuated atmosphere, and before they could come up with their prey, they lay down gasping for breath ; but these same animals have produced whelps, which have grown up, and are not in the least degree incommoded by the want of density in the air, but run down the hares with as much ease as the fleetest of their race in this country. In fact, it cannot be reasonably questioned, if the history of the domesticated races of animals be fairly considered, that changes in external conditions are capable of exerting a very decided influence upon the physical form, the habits and instincts, and the various functions of life, in species possessing this adaptiveness. The variations thus induced extend to considerable modifications in the external aspect, such as the colour, the texture, and the thickness of the external covering; to the structure of limbs and proportional size of parts ; to the relative development of the organs of the senses and of the psychical powers, involving changes in the form of the cranium, and to acquired propensities, which, within certain limits (depending, it would appear, on their connexion with the natural habits of the species) may become hereditary. Of the changes in psychical characters thus induced by external circumstances, the following are trustworthy examples. We are informed by M. Roulin (to whose researches on the changes which the domesticated races, introduced by the Spaniards into South America, have subsequently undergone, we shall frequently have occasion to refer), that a race of dogs employed for hunting deer in the platform of Santa F\u00e9, in Mexico, is distinguished by the peculiar mode in which they attack their game. This consists in seizing the animal by the belly, and overturning it by a sudden effort, taking advantage of the moment when the body of the deer rests only upon the fore-legs ; the weight of the animal thus thrown over, being often six times that of its antagonist. Now, the dog of pure breed inherits a disposition to this kind of chase, and never attacks a deer from before while running ; and even should the deer, not perceiving him, come directly upon him, the dog steps aside, and makes his assault upon the flank. On the other hand, European dogs, though of superior strength and general sagacity,\u2018are destitute of this instinct ; and for want of similar precautions, they are often killed by the deer on the spot, the cervical vertebras being dislocated by the violence of the shock.* A new instinct has also become hereditary in a mongrel race of dogs, employed by the inhabitants of the banks of the Magdalena almost exclusively in hunting the white-lipped peccari. The address of these dogs consists in restraining their ardour and attaching themselves to no individual in particular, but keeping the whole in check. Now, among these dogs, some are found, which, the very * Annales des Sciences Naturelles, 1829, tom. xvi. p. 16.\nPrinciples of Geology, seventh edit. p. 568.\n4 o 4","page":1303},{"file":"p1304.txt","language":"en","ocr_en":"1301\nVARIETIES OF MANKIND.\nfirst time they are taken to the woods, are acquainted with this mode of attack ; whereas a dog of another breed starts forward at once, is surrounded by the peccari, and, whatever may be his strength, is destroyed in a moment. The fixed and deliberate stand of the pointer, again, whether taught by the agency of man, or a habit engendered, like the preceding, by the force of circumstances, is so intimately connected with the constitution of the race, that occasionally it becomes hereditary ; a young pointer, taken into the field for the first time, being often observed to perform its duty as well as its long-trained seniors. A still more remarkable example of the transmission of acquired psychical peculiarities, is afforded by the case of the retriever, a breed of dogs which has been trained to keep close to the sportsman until he has fired, and then to go in search of the game which he has wounded or brought down. It is obvious that this habit could only have been taught by the agency of man ; and yet it has been frequently observed that a young retriever, on the very first occasion of being taken into the field, has conducted itself as well, and brought back game with as much steadiness, as older dogs which had been schooled into the same man\u0153uvre by means of the whip and collar.*\nNo really philosophical botanist or zoologist, then, should venture to establish specific distinctions between two races, otherwise than provisionally, until he has been able to assure himself that the one may not be converted into the other by a change in external conditions. Characters which are of the most trivial kind in themselves, may be valid grounds of specific distinction, if they are not liable to be thus affected ; on the other hand, characters which would be accepted in one group as sufficient for the separation of genera, may be found totally inadequate in another for the discrimination of species, being liable to modification under a very slight change of external conditions. Every one is familiar with the changes which have been induced in plants by cultivation, \u2014 how a \u201c single \u201d flower is converted into a \u201c double \u201d one ; how the spines, prickles, and thorns covering the surface may be obliterated (a change which was fancifully, but not improperly, termed by Linn\u00e6us \u201c the taming of wild fruits \u201d) ; and how the wavy leaves may become thick and fleshy (as in the change of the Brassica oleracea into the cabbage), or the slender flower-stalks may be converted into a substantial mass (as in the conversion of the same plant into the cauliflower). These changes do not, as some have alleged, throw the least doubt on the \u201c permanence of species,\u201d or favour the doctrine of \u201c transmutation \u201d in the slightest degree ; for however wide may be limits of variation, each species has its limits; and so far from having permanently advanced, under the influence of\n* See Mr. P. A. Knight\u2019s Paper on the Hereditary and Acquired Instincts of Animals, in the Philosophical Transactions for 1837.\ncultivation, to a superior type of structure, the plants thus modified will all return to their original form, when subjected to their original conditions. Numerous instances might be cited from the British Flora alone, in which the most experienced botanists are in disagreement upon the question of specific unity or diversity, simply because they have not yet ascertained the limits to the variations which the same plant may present, when growing under a variety of external conditions ; and the difficulty is yet greater when British and Continental species are compared, the variety of external conditions being greater, and the amount of allowance which should be made for their influence being known in but a few cases. The same may be said of Animals ; particularly of those on which the influence of domestication has been brought to bear. Upon this point, however, we shall defer enlarging, until the next head of the inquiry has been considered.\n3. A tendency to variation exists in many races, which manifests itself rather in modifications of the specific type presented in the course of successive generations, than in the alterations induced by external agencies in the individuals of one generation. Thus we find that the offspring of any one pair do not all precisely agree among themselves, or with their parents, in bodily conformation or in psychical character ; but that individual differences (as they are termed) exist among them. Now, as this tendency to variation cannot be clearly traced to any influence of external circumstances, it is commonly distinguished by the term c spontaneous ; \u2019 but there is much to favour the belief, that such variations are attributable to agencies operating either on both parents, previous to their intercourse, or at the time of coition, or to influences acting on the female during the period of utero-gestation.* For it may be uniformly observed, that those animals exhibit the greatest tendency to this \u2018 spontaneous \u2019 variation, which present the greatest constitutional adaptiveness to a variety of external conditions. And there are many cases in which it seems pretty clear, that the cause of this variation must be looked for in that combination of influences, which is known under the general term domestication. Thus it may be stated as a general fact, that the varieties of colour so remarkable in domesticated races, tend to disappear when these races return in any considerable degree towards their primitive wild state. This has been especially noticed in the horses, cattle, sheep, hogs, and dogs, introduced by the Spaniards into South America ; and the observation has been confirmed in other parts of the globe, showing that there is nothing peculiar to the climate of that country, which brings about the altera-\n* As these modifications are witnessed in domesticated birds no less than in mammals, it is obvious that the latter' source of influence is excluded in their case; and we must fall back upon the probability of a change in the constitution of the parents, previously to the generative act.","page":1304},{"file":"p1305.txt","language":"en","ocr_en":"1305\nVARIETIES OF MANKIND.\ntion. Now this has been attributed to the free intermixture of differently-coloured parents, which tends to confuse the breeds, and to merge those varieties which are artificially kept up among domesticated races by the matching of similar parents. But although this cause doubtless operates, yet it is far from being the whole truth ; for the converse occurrence may take place in animals which are in process of being reclaimed from their wild state, under circumstances that forbid the idea of any such intermixture. Thus, Mr. Bell informs us that an Australian bitch, or dingo, had a litter of puppies, the father of which was also of that breed ; both parents had been taken in the wild state ; both were of the uniform reddish-brown colour which belongs to the race ; and the mother had never bred before ; but the young, bred in confinement, and in a half-domesticated state, were all more or less spotted.* Now, considering the strong evidence which exists, that the colour of the offspring, in animals in which the hue is disposed to vary, may be affected by a mental impression at the time of impregnation it does not seem improbable that various differences in the general condition of a wild and of a domesticated animal, should so affect the constitution of the latter, as to occasion an amount of variation in its offspring which does not exist in the former. \u2014 The same general rule holds good in Plants. The tendency to the (so called) spontaneous production of varieties, is the greatest in those species which are most susceptible of influence by cultivation ; and those which are themselves least changed by external conditions, are those which are observed to transmit their distinctive characters most constantly and uninterruptedly from one generation to another. Further, the influence of cultivation will sometimes develop in the individual the very same departures from the usual specific type, which are, in other cases, \u2018spontaneously \u2019 manifested in the offspring of a common parent. Thus, it is well known that, by cultivation, the primrose may be converted into the polyanthus, and the cowslip into the oxslip ; but the late Dean of Manchester raised all these foul-forms from the seeds of the same plant ; and Professor Henslow has been equally successful.\nUntil the limits of this tendency to spontaneous variation have been determined, therefore, in each particular instance, no valid specific distinctions can be erected. It happens, in certain groups, that a peculiarity, in itself very trivial, is transmitted uninterruptedly from one generation to another, with such constancy and regularity as to justify us in believing that it has been always manifested. Thus many of the reputed specific differences of Moths and Butterflies rest on no other foundation, than the constant presence of a certain spot on some part of their wings ; and\n* British Quadrupeds, 2d edit. p. 203.\nf See a valuable collection of such cases by Dr. Harvey, in the Edinburgh Monthly Journal for November, 1850.\nthere are Felines, which agree so closely in the structure of their skeletons as not to be distinguishable osteologically, and which are only regarded as belonging to distinct species, because a certain stripe or spot, which uniformly shows itself on the skin of one, is as uniformly absent from that of the other. On the other hand, we see, in all our domesticated races, great diversities among the offspring of a common parentage ; and these differences are sometimes so marked, that if he had not positive evidence of this common parentage, the naturalist would undoubtedly be justified, by the importance of the diversity, in the establishment of numerous specific types, when he has really seen but a few of the varieties into which one and the same may pass.\nOf this tendency to \u201c spontaneous \u201d variation, it may be remarked, further, that like the variation which may be traced to external conditions, it has its limits, and does not really tend to confuse the boundaries of species, although it may frequently show the necessity for their extension. Thus, notwithstanding the multitude of varieties of the Apple and the Pear which we possess, and notwithstanding the apparent triviality of the specific distinction between them (this being little else than the existence of a gritty centre in the pear, which is absent in the apple), yet we never find this distinction confounded by the presence of the distinctive characters of the pear in the descendant of an apple, or by the absence of it in the descendant of a pear. So we find that, notwithstanding the multiplication of breeds of dogs and horses, sheep and oxen, pigs and poultry, they all retain the characters by which their respective kinds are distinguished from their congeners. There is no tendency to an obliteration of the distinctions between a dog and a fox, or between a horse and an ass j but these distinctions are perpetuated with the same regularity, that marks the stripes of the leopard or the spots on the wing of a moth. But, on the other hand, by observation of the spontaneous changes which particular tribes of plants or animals are liable to exhibit, we are sometimes led to extend our ideas of the comprehensiveness of species, and to bring into the same category forms which were previously supposed to be distinct types. Thus, for example, it is the opinion of many distinguished naturalists, that not only are all the breeds of Dogs to be considered as constituting one species, but that this species must also include the Wolf ; or, in other words, that the wolf and the dog are to be considered as collateral descendants from the same original parents. We shall presently examine more in detail the evidence on which this belief is founded ; supposing it to be correct, we are only required to enlarge our idea of the comprehensiveness of the species Cams lupus, which must then include all the breeds of C. familiaris as its varieties ; and none of them are in any more danger than before, of being confounded with the fox or the jackal. Until, however, the limits of","page":1305},{"file":"p1306.txt","language":"en","ocr_en":"1306\nVARIETIES OF MANKIND.\nvariation have been clearly determined in the case of any species which is known to exhibit the tendency, it is obviously impossible to erect specific distinctions that shall possess anything but a provisional value ; and thus the naturalist may feel a confident assurance of the genuineness of one set of species in a natural group, whilst he is utterly at a loss respecting another.\nReverting, then, to the \u201c idea \u201d of a species, as involving descent from a common, or at any rate from a similar parentage, in all the individuals composing it, we have to aim at ascertaining, in the case of two or more beings whose specific identity or distinctness is a question for our determination, whether their characters are presented so fixedly and deter-minately in all the individuals of the same and of successive generations, as to justify us in believing that they have been thus preserved through all time, and under all changes of external conditions. According to the amount and correctness of our information upon this question, will be the validity of our specific distinctions ; on the other hand, according to the hastiness and crudity of our decision, will be its liability to be overthrown by subsequent researches. Of course, where the progeny of any known stock can be traced through a long period of time, and under great varieties of external conditions, and their successive variations have been noted, this evidence must outweigh every argument founded upon the supposed importance of the characters which are found to undergo modification. But such opportunities are too frequently wanting ; and the naturalist is obliged to have recourse to means of discrimination which are less certain, but which will frequently conduct him, provided that his researches have been sufficiently extensive, to a satisfactory conclusion.. The great point at which he should aim, is the assemblage of as many forms as possible of each type ; and having done so, he will carefully compare them with each other, for the sake of determining whether the supposed specific characters are constant and well-marked throughout, or whether they tend to run together by intermediate gradations. If the first of these should prove to be the case, great confidence may be entertained of their genuineness ; but if the second, we may feel an almost certain assurance of their invalidity. Thus, to revert to the case of the apple and the pear, the persistence of their distinctive characters through all the numerous varieties of each, renders it almost certain, that in all other varieties which may hereafter present themselves, the same constancy will obtain; and that it has obtained during the entire succession of generations of pears and apples, from the time of their first propagation. But let us take an opposite case. T wo Terebratulce are brought together from different parts of the great Southern Ocean, the one of which has the edges of the valves of the shell thrown into deep plications, whilst in the other they are quite smooth. Now in most other Bivalve\nMollusca, such a difference would be justly admitted to afford a valid specific character ; and the conchologist who had only these two shells before him, would be justified, by the usual rules of the science, in ranking each as a distinct specific type. But as his collection extends, intermediate forms come into his possession ; and at last he finds that he can make a continuous series, passing, by the most gradual transition, from the smoothest to the most deeply plicated form. Thus, then, the supposed validity of this distinction is altogether destroyed ; and it becomes evident that the most plicated and the smoothest of these Terebratul\u0153 must be regarded as belonging to one and the same species, notwithstanding the marked diversity of their extreme forms.\nHence, whilst new types are continually being discovered, the progress of research is tending to diminish the number of species previously enumerated ; for there are many groups in which an immense reduction has been effected, by bringing together all those which are found to be nothing else than successive stages of the same individual, and by ranking under one designation all those which are either known or strongly suspected to be mere varieties, resulting from the direct influence of external conditions upon themselves or upon their ancestors, or produced through the obscurer operation of these influences on the act of generation. Frequently it is found that forms which have even been accounted generically distinct, are in reality specifically identical. Thus it has been shown by Professor Henslow, that the \u201crust of corn\u201d ( Uredo rabigo) is but an earlier form of the \u201c mildew \u201d (Puccinia graminis) ; the one form being capable of development into the other; and the fructification characteristic of the two supposed genera having been produced from the same individual. And it is asserted by Fries, that out of a single species o\u00eeThelephora, more than eight genera of Fungi have been constructed by various authors. So among higher plants, the invalidity of the generic distinctions on which reliance is usually placed, has been shown, so far as the Orchideous tribe is concerned, by the fact that the same individual has borne the flowers and pseudo-bulbs usually accounted characteristic of three distinct genera, and that another individual has presented the character of a fourth.* So in the animal kingdom, it has been shown by Professor Milne Edwards, that the polypidom of Tubulipora verrucosa, according to the circumstances under which it grows, may present the characters of three other reputed genera. If it be attached to a plane surface, as the expanded lamina of a sea-weed, it remains circular, and\n* For the first of these cases, see the Linn\u00e6an Transactions, vol. xvii. The second fell under the writer\u2019s own observation in the Durham Down Nursery, near Bristol; here, also, three different forms, generally considered as generically distinct were presented ; and two of them were the same as in the preceding case : but the third was one not exhibited by that plant.","page":1306},{"file":"p1307.txt","language":"en","ocr_en":"1307\nVARIETIES OF MANKIND.\nincreases with great regularity, constituting the Madrepora verrucosa of Fabricius. If it cluster round the cylindrical and branching stem of a Fucus, it increases irregularly, and assumes the form of the Millepora tubulosa of Ellis. If its development in any direction be checked by a mechanical obstacle, the form of the mass will again be changed, and its tubes will be recurved backwards,* a character on which Lamouroux founded his genus Obelia. Sometimes on the very same polypidom, we find one portion whose disposition corresponds with that of Millepora tubulosa, and another which, if detached, would be considered a specimen of Obelia tubulifera.* Many similar cases might be quoted ; all of them showing, not that there is any real confusion amongst species and genera, but that naturalists have too often assumed variable and non-essential characters as the basis of their systematic distinctions, in ignorance of those which are fixed and determinate. Thus, in the case in question, it is on the structure of the animal, not on the form of the polypidom, that the modern Zoophytologist places his chief reliance ; and a knowledge of this would have prevented the assignment of the varieties of coral, formed by one and the same kind of animal, to three different genera. So among Mollusca, it has been shown by Mr. Gray f that a large number of species have been formed, in consequence of the variations presented by the shells of the same species at different periods of life, or developed under different circumstances. The change from salt or fresh water to brackish, or from brackish to salt or fresh, which many species are able to sustain, appears to have a considerable influence on the form of their shells ; thus Professor E. Forbes has shown that certain Paludince and Naticce, which are found in successive tertiary strata in the island of Cos, associated in some cases with decidedly fresh-water, and in others with decidedly marine, testacea, are probably to be regarded as varieties of the same species, notwithstanding that they would be regarded by conchologists as distinct ; gradations being traceable between one form and another, and the changes being of a kind which are known to take place among fresh-water mol-lusca. J\nAs an example of the mode in which the philosophic zoologist proceeds in his examination of a doubtful case of unity or diversity of species, in a group more closely related to man, we shall consider the question of the relations of the several races of Dogs to each other. Every one is familiar with the fact that numerous breeds of dogs exist in almost every part of the world inhabited by civilised man, distinguished from each other by well-marked peculiarities, which appear to be transmitted continuously from parent\n* M\u00e9moire sur les Tubulipores, in Ann. des Sei. Nat., 2\u00e8me s\u00e9rie, Zool. tom. viii.\nf On the Structure of the Shells of Mollusca, Philosophical Transactions, 1833.\nJ Travels in Lycia, vol. ii. p. 199.\nto offspring, and thus to possess a claim to rank as specific distinctions. These differences extend to stature, form, proportions, swiftness of foot, colour and texture of hair, acuteness of sensations, intelligence, and attachment to man ; and they are particularly well marked in the conformation of the cranium, the part to which the anatomist first looks for his distinctive characters.\nThe changes in the conformation of the cranial portion of the skull, which distinguish the domesticated races of the dog from those which have been less modified by the f influence of man, partly consist in the obliteration of the sagittal crest, which rises up on the line of junction of the parietal bones, and of its continuation on the occipital bone. In the large deer-hound, we are assured by Prof. Owen, these crist\u00e6 are as strongly developed as in the wolf ; whilst in the smaller spaniel or pug, they are entirely wanting, the cranial dome being smooth and round. But \u201c such modifications,\u201d as Prof. Owen remarks, \u201c are unaccompanied by any change in the connections, that is in the disposition of the sutures, of the cranial bones ; they are chiefly due to arrests of development, \u2014 to retention of more or less of the character of immaturity ; even the large proportional size of the brain in the smaller varieties of house-dog, is in a great degree due to the rapid acquisition by the cerebral organ of its specific size, agreeably with the general law of its development, but which is attended in the varieties cited by an arrest of the general growth of its body, as well as of the particular developments of the skull in relation to the muscles of the jaws.\u201d Such an alteration is considered by this eminent anatomist as fairly referable to the influence of domestication ; since, as he remarks, \u201c no other domestic animal manifests so great a range of variety in regard to general size, to the colour and character of the hair, and to the form of the head, as it is affected by different proportions of cranium and face, and by the intermuscular crests superadded to the cranial parietes.\u201d \u201c Yet under the extremest mask of variety so superinduced,\u201d he continues, \u201c the naturalist detects in the dental formula, and in the construction of the. cranium, the unmistakable generic and specific characters of the Canis familiaris\u00e9 * Generally speaking, the cranial cavity of the domesticated dogs is relatively increased in capacity ; the facial portion, on the other hand, is offener shortened. The skull of the Australian dingo differs but little from that of a wolf. In both, the arch formed by the temporal and parietal bones is much depressed, so that the cranial cavity is small, and the head flat. The Danish dog and the mastiff resemble the dingo in the shape of their heads, and display as little of intellect or sagacity. The terrier and the hound have the parietal bones more arched, and, consequently, possess a larger cranial cavity. The greyhound has a longer muzzle, and smaller frontal sinuses than the hound ;\n* Zoological Transactions, vol. iii. p. 415.","page":1307},{"file":"p1308.txt","language":"en","ocr_en":"1308\nVARIETIES OF MANKIND.\nand the nasal cavity, though elongated, is much contracted, especially at its upper part, so that the sense of smell is less acute in this breed than in most others. The shepherd\u2019s dog, which Buffon very erroneously considered as the breed least modified by domestication, is distinguished by its remarkably capacious cranium ; the temporal bones not beginning to arch over the cavity, until they have risen perpendicularly to half their height. In the spaniel and Newfoundland dog, the capacity of the cranium is yet greater than in the preceding ; and they are also distinguished by the remarkable size of their frontal sinuses, which causes the forehead to rise almost perpendicularly from the nasal bones. The bull-dog, on the other hand, is distinguished by the shortness and extraordinary breadth of its muzzle ; while its cranium is less capacious than that of the shepherd\u2019s dog. The varieties in general conformation are not less remarkable than those in cranial configuration. Thus, the relative length of the tail is subject to great variation, even the number of its vertebrae differing so widely as from 16 to 21. Some races have an additional claw on the hind foot ; and many have an additional false molar on one or both sides. The nature of the hairy covering, too, varies in regard to its closeness or scantiness, its length, its colour, the fineness or coarseness of its texture, &c. &c. ; so that, as M. Fred. Cuvier remarks, the dog-kind presents all the varieties, in respect to the nature of the hairy covering of the body, that are to be found in the entire class of Mammalia. The form of the ears, too, is another marked feature of distinction ; these organs being short and erect in some, long and pendulous in others. The differences in habit and psychical character, also, are almost as characteristic as those of form. The greater number of dogs track their prey by scent ; and this quality may be developed by care in breeding*, so that it attains its greatest excellence in the highest-bred fox-hounds, blood-hounds, and pointers. But the greyhound hunts almost solely by sight ; and, in breeding it, every care is taken to obtain swiftness and \u201c wind,\u201d and power of enduring sudden and violent bursts of exertion. In the degree and nature of their attachment to man, again, which is the most marked psychical feature common to them all, we observe a very striking diversity. Perhaps the bull-dog is, of all the domesticated races, that which is least prone to seek the society of man ; yet, notwithstanding its obstinacy and ferocity, it does form attachments to human beings, and especially to those whose savage nature is most akin to its own. On the other hand, the pug, which seems like a dwarf-variety of the bull-dog, is remarkably timid ; and, though possessing but little sagacity, is tolerably good tempered. The mastiff, again,\n* The principal mode in which the influence of man is exerted in modifying the characters of the races under his control, consists in the selection of those individuals only for propagation, which display the desired attributes in the greatest perfection.\npossesses the determined courage of the bulldog, but is greatly influenced by kindness, and shows a generous and intelligent nature-The setter, with a considerable degree of sagacity and intelligence, is remarkable for its affectionate and grateful nature, for its docility, and for its humble and anxious solicitude to please. Of all the races of dogs, the spaniel is the one most distinguished for attachment to man ; the most timid, fond, and affectionate ; the most patient under ill treatment : it is, however, by no means distinguished for courage ; and though very docile, is not remarkable for native sagacity. It is perhaps in the shepherd\u2019s dog that the attribute of intelligence is most strikingly displayed, in combination with courage, fidelity, and perseverance : he lives in habits of constant familiarity with his master, learns to interpret his looks and words with an intuitive comprehension, and allows no difficulty or danger to prevent him from carrying his directions into effect. The Newfoundland dog, perhaps, combines more than any other breed the qualities which render the race most generally serviceable to man ; although this combination is not such as fits him for any of those special uses, to which other breeds are particularly adapted.\nNow these differences are far greater than those which exist among the acknowledged species of the feline race * ; and therefore, at first sight, might be considered as amply justifying the erection of specific distinctions among the several breeds of the canine. But the endeavour to do so would be attended with insuperable difficulties ; for, in the first place, it has been shown by M. Fred. Cuvierf, who has paid particular attention to this question, that if we assume the varieties to be permanent races, or originally distinct species, and predetermine that these races are susceptible of few or no modifications, it will be requisite to institute at least fifty different species of dogs, all distinguished from each other by recognisable characters, \u2014 a hypothesis which cannot for a moment be entertained. Moreover, every one who has much intercourse with the canine races becomes impressed with the feeling, that, notwithstanding the diversities of the greyhound and the bulldog, the blood-hound and the spaniel, the Newfoundland and the terrier, they are all dogs; and there is obviously an instinctive recognition of this fact among the animals themselves, as is seen by the readiness in which the individuals of the most dissimilar breeds will fraternise together. Further, as already remarked, there is a marked absence of tendency to variation in the characters of the feline races, the limits of each\n\u2022 The writer has been assured by Mr. S. Stutch-bury, who was formerly sub-curator of the museum of the Royal College of Surgeons, that even Cuvier proved himself unable to distinguish the cranium of a lion from that of a tiger.\nf Recherches sur les Caract\u00e8res Osteologiques, qui distinguent les principales Races du Chien domestique. Annales du Museum, tom. xviii.","page":1308},{"file":"p1309.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1309\nspecies being defined by the preservation of its characters through successive generations and under all circumstances ; the only exception to this general statement, being in the case of the domestic cat, which, like the dog, passes into numerous varieties, none of which, however, show an approximation to the characters of any other species. Hence, notwithstanding the extent of variation presented among dogs, the characters of the breeds do not bear a specific value ; for an amount of variation may be seen among the successive generations of the same breed, however pure it may be kept, or even among the offspring of the same litter, quite sufficient to show that a strong capacity for modification exists in this species. It would not be difficult, moreover, to bring together a series of individuals, that should connect the most extreme forms by imperceptible gradations ; all the different races breed together with the most complete freedom ; and, as already remarked, there is a continual tendency amongst them, if they escape from the influence of man, and intermingle unrestrainedly in a state approaching to their original wildness, to a return to one uniform type of configuration and of hue. Further, whatever their other differences in psychical character, we find that they all agree in that tendency to association with man, which is pretty obviously the chief source of those diversities ; the most important departures from the natural habits of a wild race, being those which have been impressed upon the several breeds by a long course of training, whose influence has been transmitted, to a certain extent, from one generation to another. We have seen that, in particular races of dogs existing in a half wild state, the force of circumstances, without any human intervention, has developed a new instinct, which has become hereditary within a few generations ; and there can be no difficulty in understanding, therefore, that the psychical as well as the physical characters of the dog may have undergone a far more marked alteration, in the prolonged period during which he has been under the influence of man. However considerable, then, are the anatomical and psychological differences of the most diverse breeds, these are perpetuated only by the agency of man, and tend to merge themselves in a common type as soon as this is withdrawn ; and through all these changes, the physiological conformity, as marked especially by the generative function, is constantly preserved. And thus it may be unhesitatingly asserted, that there is no such clear and well-marked natural distinction between the several breeds of dogs, as can serve to justify the assignment of a separate parentage to any of them.\nThe question next arises, whether the dog is a domesticated form of any other species of the genus Cants, e. g. the wolf, the fox, or the jackal ; or whether it is descended from an original wild stock, which has subsequently become extinct. Now the fox may be at once excluded, as differing in the\nvertical elongation of the pupil, the peculiar bushiness of the tail, and in other characters. The affinity of the dog to the jackal is certainly not so close as that which it bears to the wolf ; and there are *many distinguished naturalists who regard the latter as its original. In support of this view, the following considerations may be urged. No specific character has yet been framed so as to be equally applicable to all the breeds of dogs, which does not include the wolf also ; and it does not seem likely that any valid specific distinction can be established upon anatomical grounds only. The various races of wild dogs, in proportion to their entire emancipation from the influence of man, exhibit more and more of the lank and gaunt form, the lengthened limbs, the long and slender muzzle, and the great comparative strength, which characterise the wolf ; and in the dingo of Australia, which presents these peculiarities in the most marked degree, and which may be considered as the most remote from a state of domestication, the tail assumes the slightly bushy form of that of the wolf. In no point of its osteology does the wolf differ more from dogs in general, than they differ from each other; and the interval, in fact, is much less between the wolf and the races of dogs just alluded to, than it is between these and the races which most strongly exhibit the influence of domestication. Further, the wolf and the dog readily breed together, and their progeny is fertile with either of the parent races ; but whether the hybrids thus produced are fertile with each other, and a new race can be thus established, has not yet been ascertained. The term of utero-gestation is the same for the wolf as for the dog, viz. sixty-three days ; that of the jackal, on the other hand, is but fifty-nine. It is a remarkable fact, that the habit of harking is peculiar to dogs which have been accustomed to intimate association with Man ; and, like variety of colour, it is soon induced in the progeny of those to whom it is not natural, when these are reared in a state of domestication. Thus, the puppies of the Esquimaux dogs brought home by our Arctic explorers, being accustomed to the sound of the human voice from the earliest period, learn to bark, whilst their parents remain confined to their original sounds.\nThe principal objection to the idea of the specific identity of the two races, lies in their difference of psychical character; the wolf being apparently altogether destitute of that disposition to attach itself to man, and of that capacity of modification under his influence, which is so marked a feature in the nature of the dog. It has been asserted that the wolf is so untameably savage, that it would require ages of domestication to render it even moderately tractable, if, indeed it could ever be brought under subjection. Such an assertion, however, does not seem borne out by facts. Mr. T. Bell* relates an\n* British Quadrupeds, p. 199.","page":1309},{"file":"p1310.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1310\ninstance of friendly recognition towards himself and other persons, shown by a bitch wolf at the Zoological Gardens ; and cites from Mr. Fred. Cuvier a very remarkable instance of affectionate and submissive attachment shown by a young wolf towards the individual by whom he had been brought up, in a degree that scarcely seems inferior to that manifested by the dog. \u201c Now, if we find,\u201d he remarks, \u201c that the mere education of a young wolf, taken from its parents in a wild state, could so far change its natural disposition, and render it so fond, so intelligent, and so grateful as this, what may we not expect from the successive transmission of improvement by the culture and training of a whole race for ages ? \u201d On the other hand, in those races of dogs which have become emancipated from human control, the psychical nature of the wolf developes itself, in precise proportion to the approach presented to its physical characters. And even in the most domesticated breeds, instances of spontaneous reversion to wild habits are occasionally to be met with. \u201c Thus,\u201d says Mr. Blyth, \u201c I have known this to occur in a male pointer and a female greyhound ; the latter was so fine a specimen of the breed, that on being entrapped, it was thought desirable to obtain a litter from her, which was accordingly effected ; but while her puppies were very young, she managed to escape to the woods, and never returned ; three of her progeny grew to be excellent hounds, but two others proved quite irreclaimable, and escaping from servitude, like their dam, were finally shot, for their destructive poaching propensities.\u201d*\nThus it appears that, even if we hesitate in pronouncing in favour of the specific identity of the dog and the wolf, there is, at any rate, no valid ground for the establishment of a specific distinction between them ; and if it should prove that the hybrid offspring are fertile amongst themselves, and that a vigorous mixed race is the result, the probability of their specific identity would be greatly increased. The required proof, however, could only be afforded by the actual production from the wolf stock, of a race having the aptitude for domestication, and capacity for variation, exhibited by the dog.\nThere is another mode of looking at the question, however, which has been recently suggested by Professor Agassiz.f This distinguished naturalist thinks it impossible to account for the geographical distribution and varieties of conformation of many existing species of animals, without having recourse to the idea that, instead of all the individuals of that species having descended from a single parentage, or pair of \u2018 protoplasts,\u2019 they are the offspring of several distinct pairs of \u2018 protoplasts,\u2019 first introduced in different localities, all possessing the same essential nature, but having that nature modified in accordance with the spe-\n* Translation of Cuvier\u2019s R\u00e8gne Animal, p. 90.\nf See his recent work on the Fishes of Lake Superior ; also the Edinb. New Philos. Journ., April, 1850.\ncial conditions in which each was destined to exist. From the definition of species, therefore, he would exclude the idea of identity of descent, and would substitute that of similarity s but would still base his distinction of species, as do other naturalists, on the constant transmission of some well-marked peculiarity common to all the races, and would thus associate all those which obviously partake of a common nature, and are disposed to free intermixture, notwithstanding the non-identity of their parentage.* He would probably accord with other naturalists, therefore, in regarding the different breeds of dogs as varieties of one species ; but would attribute the origin of their several peculiarities in part to the differences in their first parents, which were not, however, sufficient to constitute specific distinctions. Although there may be cases in which such an hypothesis presents the readiest solution of the difficulty, yet it can scarcety be accepted as applicable to that of the dog ; for we do not here find that the races which most nearly approximate to the wild state in different parts of the world, do present any differences that enable us to regard them as the respective ancestors of our most diverse domesticated breeds. If, for example, it could be shown that the Esquimaux dog peculiarly resembled the mastiff, that the Indian dhole might be regarded as the progenitor of the greyhound, that the\n* Of the hypothesis of the radiation of species from several distinct centres, Prof. E. Forbes may be regarded as the most conspicuous opponent. He has laboured to show that the peculiarities in the geographical distribution of existing species are quite reconcilable with the idea of migration from single centres, and that, generally speaking, they necessarily lead to that idea ; whilst, on the other hand, in those instances in which detached or outlying spots occur, remote from the principal area of distribution, and from each other, he considers that these represent the original extent of range, which has been subsequently interrupted by geological changes that have been fatal to the existence of the species over the intermediate connecting areas, \u2014 as, by the substitution of water for land, or of land for water ; by the elevation or depression of the sea-bottom, in a degree incompatible with the continued existence of the species if it be marine ; by similar changes in the land, exerting a like influence on terrestrial species ; by alterations thus induced in the course and connection of rivers and watercourses, which have broken up the areas of fluviatile and lacustrine species ; by changes of temperature consequent upon remoter causes; and many other influences too numerous here to recount. He affirms that, in so many cases, these peculiarities may be thus explained by known geological changes, which have occurred since the introduction of the species in question (this being the case peculiarly with those that existed in the glacial epoch, and then had an extensive southern range, which is now only indicated by then* occurrence in outlying spots, the principal area of the species being now restricted to the circum-polar regions, in consequence of the more elevated temperature of the parts beyond), that we have fair ground for extending this view to all, and for inferring the occurrence of geological changes, subsequently to the first diffusion of particular species, from the peculiarities of its existing distribution. As yet, however, his views on this subject have not been given to the world in any complete form, save by oral discourses.","page":1310},{"file":"p1311.txt","language":"en","ocr_en":"131t\nVARIETIES OF MANKIND.\nAustralian dingo was the probable ancestor of the spaniel, and that the American wild-dog gives us the type of the pug, the hypothesis of Professor Agassiz might be admitted to possess a considerable claim to our reception. Rut so far is this from being the case, that, as already pointed out, the several races of wild dogs present a remarkable conformity to a common type ; and neither of them can be looked to, in preference to the others, as the probable source of those domesticated breeds which are most diverse from each other, and from the supposed common type. Moreover, there is a strong probability, considering the very remarkable character of the zoology of New Holland, that the dingo was not indigenous to that country, but that it was introduced there by its human colonizers ; thus, being a descendant of the Indian dhole, or of the same stock with it. Hence, even if we admit the multiplication of \u2018 protoplasts\u2019 in the case of the dog, we are still driven back upon the influences of domestication as the direct or indirect source of those variations from the fundamental type, by which the existing races are severally characterised.\nThe historical evidence of modification in successive generations, which is inadequate to prove the specific identity of the several races of Dogs, is much more fully supplied in the case of some other domesticated animals ; and suffices to show that although the tendency to spontaneous variation may seem to have nearly exhausted itself heretofore in the production of the most divergent forms, still there remains enough to originate new races, distinguished by well-marked peculiarities of conformation, even under our own eyes. Some of our most valuable information on this subject, is derived from the changes which have taken place in the races of domesticated animals introduced into the West Indies and South America, by the Spaniards, three centuries and a half since. Many of these races have multiplied extremely in a soil and in a climate congenial to their nature; and several of them have run wild in the vast forests of America, and have lost all the most obvious appearances of domestication, whilst they have acquired various peculiarities which distinguish them from their domesticated progenitors, some of these, perhaps, being indications of a partial restoration to the primitive characteristics of their respective races. The greatest part of our knowledge on this subject is derived from the researches of M. Roulin (already referred to) which relate to New Grenada and Venezuela, and from the well-known and justly esteemed work of D\u2019Azara on the natural history of Paraguay.\nNo zoologist has any doubt whatever, that the wild hoar is the original of our domesticated siuine; the change from the one form and condition to the other being capable of accomplishment in the course of a few generations. Yet, as Blumenbach has remarked, the difference between the two forms of crania is as great as that between the Negro and the\nEuropean skulls. And the same eminent physiologist has pointed out, that the varieties of swine in various countries, all clearly referable to one stock, exceed in their extent of divergence from it, the very widest departures of the human conformation from any one type. Thus, swine with solid hoofs were known to the ancients ; and large breeds of them are found in Hungary and Sweden, as also in some parts of England. In some other breeds there are five distinct toes, each having its own hoof. The European swine, first carried by the Spaniards to the island of Cubagua, in 1509, have been the progenitors of a race now found there, possessing toes of half a span in length. The hogs which were first introduced into South America by the Spaniards at about the same period, rapidly extended themselves over the northern and central parts of that continent ; and whilst wandering at large in the vast forests of the New World, and feeding on their original diet of fruits and seeds, they have reverted very nearly to the type of the European boar. Their colour, too, has lost the variety observable in the domestic breeds, the wild hogs of the American forests being for the most part uniformly black. The hogs which cover the mountains of the Paramos, where they are subject to severe cold and deficient nourishment, are small and of a stunted figure ; but their skins are covered with thick fur, often somewhat crisp, beneath which is found in some individuals a species of wool. In some of the warmest regions, the swine are not uniformly black, but red like the young peccari ; and elsewhere there are some, whose blackness gives place under the belly to a white band, which reaches up to the back.\nThe question of the original source of the various breeds of ox, will not be now discussed; it is sufficient for dtir present purpose to notice some of the most remarkable departures from the European type, which have shown themselves in the South American descendants of the individuals first introduced there by the Spaniards. In the year 1770, as we learn from D\u2019Azara, a hornless bull was produced in Paraguay, which has been the progenitor of a race of hornless cattle that has since multiplied extensively in that country. So, again, as we are informed by M. Roulin, in some of the hot provinces of South America, a variety of ox has been produced, which is noted for its extremely rare and fine fur. This variety tends to perpetuate itself ; but it is not encouraged, because the \u201c pelones \u201d (as they are termed) are too delicate in constitution to bear the cold of the Cordilleras, to which the cattle are driven for the provision of the towns situated upon them. These pelones obviously constitute a variety adapted for a particular climate ; oxen of other breeds frequently perishing when driven into the provinces inhabited by them, or being with difficulty acclimatised.* But the same hot provinces\n* Hence we see that so much of Prof. Agassiz\u2019 argument for the multiplicity of specific centres, as","page":1311},{"file":"p1312.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1312\noccasionally produce another curious variety, characterised by the entire absence of hair ; these naked-skinned oxen, which are called \u201c calongos,\u201d are, like the pelones, unable to bear a cold climate, and are very delicate and weak. Another remarkable fact, relative to the oxen of South America, is recorded by M. Roulin. In Columbia, the practice of milking cows was laid aside, owing to the great extent of the farms and other circumstances. In a few generations, the natural structure of the parts and the natural state of the function have been restored ; the secretion of milk taking place only so long as the calf remains with the mother, and ceasing if it dies or is removed. Hence we have a valuable confirmation of the belief previously entertained, that the continued production of milk by the European breeds of cows is a modified function in the animal economy, originating in an artificial habit kept up through many generations, and dependent upon a modification of structure which that habit has been the means of inducing.\nThat the various breeds of sheep at present domesticated in Europe, have had a common origin, is not doubted by any zoologist, notwithstanding the differences in their stature and proportions, the texture and colour of their wool, the presence or absence of horns, &c. The most marked deviation from the usual type is presented by a breed of Spanish sheep, distinguished by the length and straightness of the hair, and by the length and spiral twist of the horns. Various breeds are found in Asia and Africa, as to whose specific unity with each other, and with European sheep, zoologists are not agreed. We have a remarkable example of climatic variation, however, in the fact, that in the races spread through Persia, Tartary, and China, the tail seems replaced by a double spherical mass of fat, which forms a most awkward excrescence on the rump, and is nearly destitute of hair; whilst these sheep, transferred to the cold, dry pastures of Siberia, are affirmed by Ermann to lose this peculiar conformation in the course of a few generations. The sheep of Syria and Barbary, on the other hand, have an accumulation of fat in the tail itself, which is long, and sometimes attains a weight of from seventy to one hundred pounds. It is a curious and very significant fact, that the sheep of the Cape of Good Hope, which are descended from the European stocks, should exhibit the same tendency to the accumulation of fat about the rump, as is seen in the human races indigenous to that region. The sheep which were transported into South America by the Spaniards, have not multiplied so extensively as the oxen and swine ; and from their more limited diffusion, we find, as might be expected, that they exhibit but a comparatively slight amount of variation. The remarkable change in the\ndepends upon the adaptation between the constitution of the several races and the climates in which we find them, is deficient in solidity of foundation.\ncharacter of the hair, presented by the sheep in the West Indies has been already referred to. \u2014 Among sheep, as among other domesticated animals, new races are continually being produced by breeders, not merely by crossing or intermixing races already constituted and well known, but also by taking advantage of peculiarities which occasionally present themselves spontaneously, and using means to perpetuate these. The following is one of the most curious examples of this kind upon record. In the year 1791, a ewe on the farm of Seth Wright, in the state of Massachusetts, gave birth to a male lamb, which, without any known cause, had a longer body and shorter legs than the rest of the breed ; the joints also were peculiarly formed, and the fore-legs crooked. The conformation of this animal rendering it unable to leap over fences, it was thought desirable to endeavour to propagate its peculiarities ; and accordingly when it was fit for procreation, several ewes were impregnated by it. Out of the lambs first produced, only two presented the same peculiarities ; more were obtained in subsequent years ; and when they became capable of breeding with each other, the new race was completely established ; its distinctive characters being uniformly presented when both parents possessed them, but tending to disappear when the sheep of the \u201c ancon \u201d or \u201cotter\u201d breed (as it is called) were allowed to breed with those of the ordinary type.* This fact, as we shall hereafter see, has an important bearing on the question of the spontaneous origination of permanent varieties, in the human or any other species that is disposed to undergo occasional modifications ; which modifications, under ordinary circumstances, disappear as often as they recur. Thus it is not uncommon to meet with families distinguished by the possession of some peculiarity of feature, or by some well marked departure from the ordinary conformation, such as the possession of six fingers on each hand and six toes on each foot. If such were to intermarry exclusively with one another, there can be no reasonable doubt that the children would invariably exhibit the same peculiarity ; and that the six-fingered race, which now tends, whenever it is originated, to merge in the prevailing five-fingered type, would then become permanent. When it is considered that the influence of a scanty population, in the early ages of the world, by isolating different families from each other, and causing inter-marriages amongst even very near relatives, would have been precisely the same with that which is now exercised by the breeders of animals, we see one reason why the varieties which then arose should have had a much greater tendency to perpetuation, than those which now occasionally present themselves.\nIn regard to the horse, it will be sufficient to observe that no zoologist has ever ex-\n* See Col. Hutchinson\u2019s Memoir in the Philo* sophical Transactions for 1813.","page":1312},{"file":"p1313.txt","language":"en","ocr_en":"1313\nVARIETIES OF MANKIND.\npressed any doubt of th# specific unity of all the domesticated breeds, or of their identity of origin with the so called \u201c wild horses \u201d of Northern Asia : which are probably descended from domesticated progenitors. Yet their diversities in stature, conformation, &c. are very considerable. Thus the ordinary height of the Shetland pony is from eight to ten hands ; and individuals have been occasionally seen which were no more than seven. On the other hand, the draught horse commonly stands from sixteen to seventeen hands ; and not unfrequently surpasses this height. In regard to the conformation of the skull, again, it has _ been remarked by Blumenbach, that there is more difference between the elongated head of the Neapolitan horse and the skull of the Hungarian breed, which last is remarkable for its shortness and the breadth of the lower jaw, than there is between the most dissimilar human crania. The differences in general constitution, also, as regards the power of sustained effort on the one hand, or of intense exertion for a short period on the other, are no less remarkable. But the breeds which are furthest removed from each other in these particulars are connected by such a gradual series of transitional forms, that there is no possibility of drawing a line between them ; and, like the various races of dogs, sheep, &c., they freely intermingle with each other, and produce offspring which are as fertile with their own kind, as with either of the parent stocks. It has been, in fact, by such intermixture of the large and powerful races of Northern Asia with the lighter and more agile horses of Arabia and Barbary, that many of the European breeds have been obtained. The wild horses which at present range over the plains of Tartary differ from the domesticated races in several particulars ; thus, as we are informed by Pallas, the cranium is relatively larger and more vaulted, the limbs are stronger, the back is less arched ; their hoofs are smaller and more pointed; their ears are longer and bent more forward. Their habits, moreover, are peculiar; for they associate together in herds or troops to the number of several thousands, spreading abroad to feed, but congregating together on the appearance of danger, and seemingly putting themselves under the direction of a leader; on the approach of an enemy they close into a dense crowd, and, attacking the intruder, trample him to death ; or, like many other gregarious animals, the females, the young, and the weak being placed in the rear, the stronger individuals array themselves in front, and fight most vigorously with their heels. Now these peculiarities of structure and habit are not only seen in the wild horses of Northern Asia, but also in those which have spread themselves over the extensive plains of South America, since their introduction into that continent by the Spaniards ; and it is nearly certain that the former, like the latter, are the descendants of a domesticated stock, whose return to something like the\nVOL. IV.\noriginal condition of the species, has reproduced (at least in some degree) the original instincts, which had been entirely subdued for a time by the influence of domestication. In the horse, as in the dog, we have evidence that the habits which are developed by human training may become, to a certain extent, hereditary. Thus, it is observed that the wild horse has no pace but the walk and the gallop; the trot, to which European horses are usually trained, is an acquired habit, yet it obviously \u201c comes naturally\u201d to the colt of a domesticated breed; and, in like manner, the peculiar pace to which the South American horses are trained (which is a kind of running amble, the two legs of the same side being moved forwards together) is used without any instruction by the offspring of those by whom it has been acquired. Another example of the transmission of acquired propensities in horses is mentioned by Mr. Knight: the Norwegian ponies have been taught to obey the voice of their riders rather than the bridle ; and the English horse-breakers complain that it is impossible to produce the latter habit in the offspring of this race placed under their tuition, notwithstanding that they are exceedingly docile and obedient when they understand the commands of their master, as imparted by word of mouth. It is equally difficult, he adds, to keep them within hedges, owing, perhaps, to the unrestrained liberty to which the race may have been accustomed in Norway.\nFrom the present condition and past history of the domesticated races of Mammalia, of which a general survey has thus been taken, some important inferences may be drawn, which it may be advisable to put in the shape of formal propositions ; since in this manner we shall be able to define our terms more strictly, and to use these definitions as the foundation for our future investigations into the relationship of the several branches of the Human family.\n1.\tRaces of living beings are, properly, successions of individuals propagated from any given stock ; and the term implies no more than the fact of the transmission of a distinctive character by descent.\n2.\tTwo races, distinguished by well-marked peculiarities, may rank either as distinct species, or as varieties of the same species ; being supposed, in the first case, to be descended from parents which themselves originally exhibited the same peculiarities ; and being considered, in the second, as the descendants of an identical, or, at any rate, of a similar, parentage.\n3.\tThe question of unity or diversity of species, between two races, cannot be decided by the degree of difference which exists between them ; for the answer to it entirely depends upon the constancy with which the peculiarity (of whatever nature it may be) is transmitted from parent to offspring, and upon the amount of variation which is exhibited even within the acknowledged limits of the\n4 p","page":1313},{"file":"p1314.txt","language":"en","ocr_en":"1314\nVARIETIES OF MANKIND.\nrespective races. And thus a character which is perfectly valid in one group, may be entirely inapplicable in another.\n4.\tTwo races can only be regarded 1 as specifically distinct, when the characters which separate them are transmitted with complete uniformity from parent to offspring ; when there are no intermediate gradations tending to connect them ; and when no such tendency to variation has manifested itself in either race, as shall make it probable, or, at any rate, possible, that their differences may be the direct result of external influences, or may be attributed to an unusual divergence in the characters of the offspring from those of the parents.\n5.\tOn the other hand, two races may undoubtedly be regarded as specifically identical, when, however great the differences in stature, conformation, psychical character, &c., presented by their respective types, these types are connected with each other by intermediate gradations, so close as to render it impossible to establish a definite boundaryline between the collections of individuals which are assembled around them.\n6.\tAgain, two races may be undoubtedly regarded as specifically identical, when in either race varieties present themselves, which exhibit the distinctive characters of the other race ; since we then have evidence, that, although these peculiarities are so generally transmitted from parent to offspring that each race possesses a certain degree of permanence, yet they are not thus uniformly inherited ; and, consequently, there is nothing to prevent the transformation of the one race into the other, if the circumstances which have originated the variation, even in a single case, should act with sufficient potency on the whole mass.\n7.\tNo character can be safely adopted as justifying the assumption of the specific diversity of two races, which has been found by experience to undergo considerable modification in either race, even though such modification should not proceed to the extent of conversion into the character of the other ; for if a limited amount of change in external conditions be found capable of effecting a certain degree of alteration, the probability is strong that the higher difference may have had its origin in the more potent operation of the same class of causes.\n8.\tThe very fact of the extensive dispersion of a race, and of its existence under a great variety of external conditions, implies a marked capacity for variation ; since without such capacity, the race could not continue to flourish.\n9.\tAmong the conditions which most tend thus to produce varieties, within the limits of species, are those that are included under the general term domestication ; and the widest divergence among these varieties is to be found in those species, which are brought into the closest relation to Man.\n10.\tAmong the domesticated races of quadrupeds, the characters most susceptible of\nvariation are,\u2014 1. Stature ; \u2014 2. General conformation of the body, as dependent upon the proportionate development of the limbs and trunk, the proportion of the breadth and thickness of bones to their length, the relative development of the soft tissues in different parts, &c. &c. ;\u20143. Conformation of the skull, as shown especially in the relative development of the cranial and facial portions, the capacity of the cranial cavity, and the elongation of the muzzle ; \u2014 4. Quantity, texture, and colour of the hairy covering ; \u2014 5. Psychical character, as shown in the increase of intelligence, in the acquirement of new methods of action, and in the disappearance of some of the natural instinctive propensities.\n11.\tIn every race of domesticated animals, new varieties, departing more or less from the parent stock, in one or more of these characters, are occasionally produced ; some of these being directly traceable to the influence of external conditions, whose action upon a long succession of generations gradually modifies the character of that part of the race which is exposed to it; whilst others originate in the production of offspring, which, from some cause not understood, present a marked departure from the parental type. In the first case, the variety is permanent, that is, it tends to hereditary transmission so long as the same conditions exist ; and thus arise the peculiar adaptations between the characters and constitutions of races, which have been dispersed through regions very dissimilar in their physical conditions, and the climate, food, &c., to which they have been respectively habituated. In the second case, the variety is transitory, the individual peculiarity tending to disappear in the course of two or three generations, by becoming merged in the more general type ; but if it should happen that the individuals thus distinguished should breed together, the peculiarity shows a tendency to perpetuation by hereditary transmission ; and thus an entirely new race may originate, which remains distinct so long as it is not allowed to breed with others.\n12.\tThe several races of any kind of domesticated animals, which, according to the foregoing criteria, are accounted as belonging to the same species, breed freely and spontaneously with each other, when allowed to do so ; and the offspring are fertile, not only with either of the parent races, but with each other. The mixed races thus originating, it may be added, frequently surpass either of their parent stocks, not only in the advantageous combination of different attributes, but also in general vigour, and in procreative capacity ; so that the mixture of races which are specifically identical, tends to the multiplication of the species as a whole.\n13.\tOn the other hand, although propagation may take place between individuals of undoubtedly distinct species, yet there is little spontaneous tendency to such admixture ; for each animal will select one of its own species for sexual intercourse, in preference to one of another species ; and it is, con-","page":1314},{"file":"p1315.txt","language":"en","ocr_en":"1315\nVARIETIES OF MANKIND.\nsequently, only when restricted by artificial interference, that a male and a female of different species are disposed to copulation with each other. The hybrid offspring of this act partake of the characters of both the parent stocks, but are deficient in generative power ; so that, although a mule may be fertile when paired with an individual of either of the parent races, it is seldom or never fertile with one of its own kind. Thus the peculiarities introduced by hybridity are speedily merged into those of the parent stocks ; and no new race has ever been known to originate from this kind of union.*\n14.\tAmong all those races which are entitled to rank as varieties only, the physiological conformity is often closer than the structural ; thus, as Dr. Prichard has pointed out \u201c the great laws of the animal economy, all the principal facts which relate to the natural and vital functions, the periods and duration of life, the economy of the sexes, the phenomena of parturition and reproduction, are, with slight deviations resulting from external agencies, constant and uniform in each particular species.\u201d\n15.\tSo, again, among the varieties of the\nFig. 803.\nsame species, there is, with subordinate differences, such as can be traced to external agencies, and particularly to human influence, a very close psychical conformity ; the capacities of the several races being fundamentally the same, although varying in their degree of relative development.\nIII. General Survey of the Diversities, in Physical and Psychical Characters, PRESENTED BY THE DIFFERENT\nRaces of Mankind.\nIf it were possible to bring together under one view, characteristic examples of every type of Human conformation which the progress of Ethnological research has hitherto made known, it would be found that they all accord in the peculiarities by which Man has been shown (Sect. 1.) to be distinguished from even the highest of the Quadrumanous order ; and that, notwithstanding a certain amount of approximation which is presented to that order in the aspect of certain human countenances {figs. 803, 804, 805.), and even in the habits of life of certain tribes, yet the essential and fundamental\nFig. 804.\nNegro of Bournou. (From a portrait taken under the direction of Prof. Milne-Edwards.)\npoints of difference are never obliterated. But among these types we should find so wide a diversity, that we should naturally be led to question their relationship to each other and to ourselves ; and should seek to determine whether these differences are inherent and unalterable in each race, so as to\n* It is not quite certain whether mule or hybrid Animals have ever produced fertile offspring when matched with each other ; but it is quite certain that if a second generation of hybrids has thus been engendered, a third has never been, the race having no capacity for perpetuation. Among Plants, the limits are wider, a third and even a fourth generation having been thus sometimes produced; but there is obviously a want of fertility, and a consequent tendency to extinction, in all hybrid races whose parents are specifically different.\nforbid the idea of any essential modification, either in the past or the future, from the influence of external circumstances ; or whether there is any probable evidence that they may have been produced by those external agencies, which we have seen to possess such a remarkable power of altering the conformation, and even the instinctive propensities, of domesticated animals. Such is the first question which we should have to answer ; and in a practical point of view, as influencing our conduct towards the races which differ more or less widely from our own, it is undoubtedly the most important. But the physiologist and the zoologist seek to attain a more positive scientific determination of this relationship : and since, if such a determination\n4 p 2","page":1315},{"file":"p1316.txt","language":"en","ocr_en":"1316\nVARIETIES OF MANKIND.\ncan be attained, the practical question is at once and completely settled, we shall apply\nFig. 805.\n' Tasmanian female. (From the \u201c Atlas du Voyage de VAstrolabe.\u201d')\nWhat, then, is the true zoological relationship between these different races, so dissimilar in colour, features, bodily conformation, stature, habits of life, and moral and intellectual cultivation ? Have we any ground to consider them as distinct species ? or are we to regard them as varieties of one and the same species ? Are the fair Circassian and the jet-black African, the olive Malay and the red American, the dusky New Zealander and the florid Saxon, all of one original stock ? Did the Patagonians, whose average height is nearly six feet, spring from the same parents with the pigmy Bosjesmans, whose usual height is under five, that of the females rarely much exceeding four ? Are the fat, blubber-fed, flat-visaged Esquimaux even most distantly related to the lean, date-eating, hatchet-faced Arab ?\t\u201c Does the Bosjesman, who lives in\nholes and caves, and devours ants\u2019 eggs, locusts, and snakes, belong to the same species as the men who luxuriated in the hanging gardens of Babylon, or walked the olive-grove of Academe, or sat enthroned in the imperial homes of the Caesars, or reposed in the marble palaces of the Adriatic, or held sumptuous festivals in the gay salons of Versailles ? Can the grovelling Wawa, prostrate before his fetish, claim a community of origin with those whose religious sentiments inspired them to\nSile the prodigious temples of Thebes and lemphis, to carve the friezes of the Parthenon, or to raise the heaven-pointing arches of Cologne ? That ignorant Ibo, muttering his all-but inarticulate prayer, is he of the same ultimate ancestry as those who sang deathless strains in honour of Olympian Jove, or of Pallas Athen\u00e8 ; or of those who, in a purer worship, are chanting their glorious hymns or solemn litanies in the churches of Christendom ? That Alfouro woman, with\nourselves to the search for it, as fully as our present limits permit.\nFig. 806.\nAramanga youth. (From a portrait in Dr. Pickering\u2019s \u201c Natural History of Man.\u201d )\nher flattened face, transverse nostrils, thick lips, wide mouth, projecting teeth, eyes half closed by the loose swollen upper eyelids, ears circular, pendulous, and flapping ; the hue of her skin of a smoky black, and, by way of ornament, the septum of her nose pierced with a round stick some inches long, \u2014is she of the same original parentage as those whose transcendent and perilous beauty brought unnumbered woes on the people of ancient story, convulsed kingdoms, entranced poets, and made scholars and sages forget their wisdom ? Did they all spring from one common mother ? Were Helen of Greece, and Cleopatra of Egypt, and Joanna of Arragon, and Rosamond of England, and Mary of Scotland, and the Eloisas, and Lauras, and Ianthes, \u2014 were all these, and our poor Alfouro, daughters of her who was \u2018 fairest of all her daughters, Eve ? \u2019 The Quaiqua or Saboo, whose language is described as consisting of certain snapping, hissing, grunting sounds, all more or less nasal,\u2014is he, too, of the same descent as those whose eloquent voices \u2018 fiilmined over Greece,\u2019 or shook the forum of Rome, or as that saint and father of the church surnamed the \u2018golden-mouthed,\u2019 or as those whose accents have thrilled all hearts with indignation, or melted them with pity and ruth, in the time-honoured halls of Westminster ?\u201d*\nThis question is capable of being considered under a great variety of aspects. There are many very excellent persons, who think it quite sufficiently answered by the authority of the Scriptural narrative, and who maintain that to this authority all opposing considerations\n* From an Introductory Lecture, entitled \u201c Our Institution and its Studies ; \u201d by Dr. J. A. Symonds. Bristol, 1850.","page":1316},{"file":"p1317.txt","language":"en","ocr_en":"1317\nVARIETIES OF MANKIND.\nmust give way. But, on the other hand, the conviction is now fast spreading among enlightened thinkers, that the Scriptures are no more intended to teach men Ethnology than to instruct them in Geology or Astronomy ; and that the former, like the latter, is a-legitimate object of scientific investigation, and should be pursued without fear as to the results. Any attempt, in fact, to fetter the scientific inquirer by the supposed authority of inspiration, is certain to damage the latter in the estimation of the most intelligent part of mankind ; for, as has been well remarked by a very orthodox theologian, Dr. Henry More, \u201c the unskilful insisting of our divines upon the literal sense of Moses has bred many hundred thousands of atheists.\u201d But even those who profess to place the most implicit confidence in the declarations of the Scriptures, as to the common origin of all the races of mankind, do, in effect, get rid of all the force of these declarations, when it suits their purpose to do so, by the mode of interpreting them which they adopt. They assert that the Adamic race does not include the barbarous inhabitants of remote regions ; and that Negroes, Hottentots, Esquimaux, and Australians are not, in fact, men in the full sense of the term, or beings endowed with mental faculties similar to our own. They contend that these and other uncivilised tribes are inferior in their original endowments to the proper human family, which supplied Europe and Asia with inhabitants ; and that, being organically different, they are separated by an \u201c impassable barrier\u201d from the race which displays in the highest degree all the attributes of humanity, and can never be raised to an equality with it. They maintain that the ultimate lot of the ruder tribes is a state of perpetual servitude ; and that if, in some instances, they should continue to repel the attempts of the civilised nations to subdue them, they will at length be rooted out and exterminated from every country on whose shores Europeans shall have set their feet.\nNow if the distinct origin of these tribes be admitted, \u2014 if we are to regard the Negro and Australian, not as our fellow-men, brethren of the same great family as ourselves, but as beings of an inferior order, \u2014 and if duties towards them were not contemplated, as we may in that case presume them not to have been, in any of the positive commands on which the morality of the Christian world is founded, our relations to those tribes will appear not to be very different from those which we might consider ourselves to hold towards the higher races of brutes. If such races be not men, then the golden rule, \u201c Whatsoever ye would that men should do unto you, do ye even so unto them,\u201d is not applicable to our intercourse with them. We can scarcely imagine a Grotius or a Puffendorf, or any other great jurist, attempting to determine the jus belli or pads between ourselves and a tribe of orangs, who had just sense enough to pass for men, and began to be suspected of the cheat, \u2014 which is nearly the true character\nof the Negroes, if those are right who maintain the doctrines just alluded to. And we may go a step further, and assert that there is, in such a case, no moral principle which should prevent a hungry wanderer in Negroland or Australia from satisfying his appetite, by killing and eating the first native he might happen to meet.\nThus, then, the widest extremes of opinion, and the greatest diversity in those rules of conduct which are founded upon such opinions, may exist among those who profess the most implicit reverence for the scriptural dictum, that \u201c God hath made of one blood all nations of men, for to dwell on all the face of the earth.\u201d For, whilst some include under the term \u201c men,\u201d all the individuals grouped together by the naturalist under the genus homo, and regard this genus as consisting of but a single species, of which the several races are only to be ranked as varieties, others assert that this genus includes several species, which form a gradual transition from the highest and most cultivated races of mankind, to those degraded races, which (as they affirm) have more in common with the brutes ; the former alone being really entitled to the appellation men, whilst the latter should be called by some other name indicating their close affinity to chimpanzees and orangs. Thus we are thrown back upon scientific inquiry, as the only legitimate means of bringing this question to an issue ; and such an inquiry can only be rightly pursued, when it is prosecuted upon the broadest possible basis, and is made to comprehend every kind of information which can be brought to bear upon it. Nothing can be easier than to bring together an ex parte collection of facts, which shall give to either doctrine, \u2014 that of the specific unity, or that of the specific diversity, of the human races, \u2014 an apparently fair claim to reception. But since both cannot be true, and since the question can only be decided by the balance of probabilities, no evidentiary fact having any relation to the subject ought to be left out of view ; and thus the science of Ethnology must be built upon the foundation afforded by numerous other departments of scientific inquiry. The anatomist examines the configuration of the body, and compares the peculiarities of the various tribes, with the view of determining how far structural differences prevail over resemblances, and of ascertaining whether these differences possess that constant and untransitive character, which the naturalist requires as a justification of specific distinction. The physiologist searches into the history of the vital functions in the several types of humanity, and seeks for information with regard to the permanence of anatomical differences, the effects of external agencies in modifying the configuration or constitution of the body, and the tendency to spontaneous variation in the forms presented by individuals, families, or tribes, known to be of the same stock. The psychologist has a most interesting subject of investigation, in the study of the psychical constitution of the","page":1317},{"file":"p1318.txt","language":"en","ocr_en":"1318\nVARIETIES OF MANKIND.\nseveral races, and in the extraction (so to speak) of their respective mental and moral characters, from their habits of life, their languages, and their religious observances. It is his business to inquire how far one common psychical character can be inferred from such diverse manifestations ; that is, how far the differences which he cannot but observe in intellectual capacity, and in moral and even instinctive tendencies, are fixed and permanent, or are liable to spontaneous variation, or to alteration from the modifying influence of education and other external conditions. The physical geographer lends his aid, by bringing to bear upon the inquiry his knowledge of the outward circumstances under which these variations in bodily and mental constitution are most constantly found. And it is from the materials which he contributes, that the physiologist and the anatomist have to determine the degree in which these circumstances can be justly considered as the causes of variation ; and, more especially, whether the coincidences between particular bodily configurations or mental constitutions, and certain combinations of climatic and geological conditions, are the result of induced differences among the human races which are respectively subject to the latter, or are to be attributed to the implantation of originally dissimilar stocks in the respective localities in which their descendants are now found. But in order to carry on these researches, the information of the historian is continually needed, on the actual descent, migrations, conquests, &c. of the nations whose physical and mental characters we are comparing. The question of the fixity of all or any of the characters by which the races of mankind are at present distinguished from each other, requires for its solution a comparison of the present with the past. No valid proof of their permanence can be drawn from the limited experience of a few generations ; and no evidence of change can be reasonably looked for, except under the long-continued agency of modifying causes. The required information is sometimes supplied by direct historical testimony ; but this is frequently insufficient, and recourse must be then had to the philologist, who derives from the comparative study of the languages of different tribes, most important evidence as to their degree of filiation, and thus extends, combines, and confirms the indications, which the historian had drawn from other sources. Independent of the aid which philological research affords to other departments of ethnology, it directly bears upon the great problem of the unity or identity of mankind ; for it not only answers a common purpose with historical testimony, in establishing the genealogical relations of tribes long since dispersed from their original centres, and separated at present by strongly-marked physical and psychical differences ; but it also affords important evidence as to the fundamental similarity, if not identity, of the primitive stocks.\nIt is obviously impossible to enter at any\nlength into any one of these topics of inquiry, within the limits of the present article ; and all that will be here attempted, will be to place before the reader a general r\u00e9sum\u00e9 of the whole subject, carrying out those portions into somewhat more of detail, in which the anatomist and physiologist are most concerned.\nThe question at issue has usually been considered under the simple aspect of specific unity or diversity ;\u2014 that is, in the first place, whether all the existing races may be supposed to be the descendants of one pair of \u201cprotoplasts;\u201d all their diversities in physical conformation, in language,in mental character, and in social condition, having since arisen ; \u2014or whether, secondly, the existing races must be regarded as having sprung from several distinct pairs of protoplasts ; which originally presented differences amongst themselves, nearly the same with those which now exist amongst the races that seem most remote from each other. Now the first of these suppositions requires that evidence should be given of a very considerable amount of variability from the original type (whatever that may have been) amongst the descendants from the common ancestry : whilst the second is based on the idea, that the leading characters which now separate the different races are permanent, and must have been presented bv their original progenitors. A third supposition, which has been put forward within the last few years, regards the existing races as not all proceeding from one pair of \u201c protoplasts,\u201d but from several; but considers that these, though scattered over the globe, were fundamentally similar in corporeal and mental constitution, and differed only in the adaptation of certain of their physical characters to the different circumstances of their several abodes, \u2014 thus being all comprehensible within the limits of one species,\u2014 and all possessing, too, a certain capacity for variation, which has been manifested in the production of subordinate diversities, and has even proceeded, in some instances, under the prolonged influence of change of climate, civilization, &c., to soften down, if not entirely to obliterate, the original differences. On the general bearing of the last of these hypotheses, a few remarks seem called for.\nAlthough the same affinity or blood-relationship w'ould not exist between the descendants of several distinct pairs of \u201c protoplasts,\u201d as between those of a common ancestry, yet the moral relations between them would be as close as on the supposition of their consanguinity. For, as has been justly observed, \u201c the moral rights of men depend on their moral nature ; and while Africans have the hearts and consciences of human beings, it could never be right to treat them as domestic cattle or as wild fowl, if it were ever so abundantly demonstrated that their race was but an improved species of ape, and ours a degenerate kind of god.\u201d* This view has recently been very forcibly\n* New Quarterly Review, No. XY. p. 131.","page":1318},{"file":"p1319.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\nurged by Professor Agassiz, who has adopted in regard to the human races the same views as he has put forth with respect to many other species (p. 1310.) ; and who thus upholds the \u201c unity of mankind,\u201d whilst contending for the diversity of \u201c protoplasts.\u201d\n\u201cWe recognise,\u201d he says, \u201c the fact of the unity of mankind. It excites a feeling that raises men to the most elevated sense of their connection with each other. It is but the reflection of that Divine nature which pervades their whole being. It is because men feel thus related to each other that they acknowledge those obligations of kindness and moral responsibility which rest upon them in their mutual relations. And it is because they have this innate feeling, that they are capable of joining in regular societies, with all their social and domestic affinities. This feeling unites men from the most diversified regions. Do we cease to recognise this unity of mankind, because we are not of the same family, because we originate in various countries, and are born in America, England, Germany, France, Switzerland ? Where the relationship of blood has ceased, do we cease to acknowledge that general bond which unites all men of every nation? By no means. This is a bond which every man feels more and more, the farther he advances in his intellectual and moral culture, and which in this development is continually placed upon higher and higher ground ; so much so, that the physical relation arising from a common descent is finally entirely lost sight of, in the consciousness of the higher moral obligations. It is this consciousness which constitutes the true unity of mankind.\u201d This unity, he continues, may become a yet stronger bond of moral affinity, than that afforded by community of descent. \u201c Where men of the same nation, individuals whose studies, whose calling in life have developed in them the same faculties, the same feelings, are brought closely together, relations spring up between them so intimate as by far to outweigh the natural bonds which a common parentage may establish between men. Such individuals do not feel themselves to be near each other, do not sympathise in their aspirations, do not join in the same purposes, because they are brothers, because they belong to the same family, because they are of the same nation ; but because they feel that they are men, and that the natural dispositions wherewith they are endowed as men are developed in them in a similar manner, and with reference to the same great human interests. Is there any one who would consider the ties between two such individuals on that intellectual and moral ground, as lessened because they may not be physically related at all ? or who would consider the differences in their physical features as an objection to their being more intimately connected than other men who in features resembled them more, or are related to them more closely, perhaps by the nearest ties of blood ? We can therefore take it as a matter of fact, that, as we find men actually living together in the world, it is not\n1319\nthe physical relation which establishes the closest connection between them, but that higher relation arising from the intellectual constitution of man.\u201d Professor Agassiz then refers to various departments of Natural History, as affording proof \u201c that the closest and most intimate unity may exist without a common origin, without a common descent, without that relationship which is often denoted by the expression \u2018 ties of blood.\u2019 On the other hand, that these ties of blood may exist, without necessarily calling forth the higher connections which may be found between individuals of the same type, is, alas ! too plainly shown by the history of mankind. The immediate conclusion from these facts, however, is the distinction we have made above, that to acknowledge a unity in mankind, to show that such a unity exists, is not to admit that men have a common origin, nor to grant that such a conclusion may be justly derived from such premises. We maintain, therefore, that the unity of mankind does not imply a community of origin for men ; we believe, on the contrary, that a higher view of this unity of mankind can be taken, than that which is derived from a mere sensual connection; that we need not search for the highest bond of humanity in a mere animal function, whereby we are most closely related to the brutes.\u201d*\nThe Anatomical differences by which the several races of Mankind are distinguished from each other, may be referred to the following heads : \u2014\n1.\tConformation of the cranium.\n2.\tConformation of the pelvis.\n3.\tConformation of other parts of the skeleton.\n4.\tColour of the skin.\n5.\tColour, texture, and mode of growth of the hair.\nBy most writers on the diversities of mankind, the varieties which are observable in the conformation of the bony skeleton, and particularly in that of the cranium and pelvis, have been thought to furnish distinctive characters of more importance than those derived from the colour of the skin, or the texture of the hair; since, while a certain capability of alteration in the latter, under climatic influences, can scarcely be gainsayed, it might be supposed, \u00e0 priori, that strongly marked peculiarities in the configuration of the skull, in the proportion of the parts of the body, and in the development of the brain, would be less likely to undergo alteration. Special attention will be here bestowed, therefore, upon the first three of this series of characters.\n1. Conformation of the Cranium. \u2014 In estimating the degrees of diversity presented by the skulls of various races, it is absolutely necessary that some definite method of comparison should be fixed upon. The first attempt of this kind of which we have any account, was made by Camper ; who main-\n* Christian Examiner, Boston, N.E. Jan. 18i0.\n4 p 4","page":1319},{"file":"p1320.txt","language":"en","ocr_en":"1320\nVARIETIES OF MANKIND.\ntained that the profile view is the most characteristic, and that the \u201c facial angles \u201d of the different races vary so greatly and so constantly, that upon this character alone a valid distinction might be founded. By Blumenbach, on the other hand, it was considered that the comparison of the breadth of the head, particularly as seen in the vertical aspect, is the method by which the most strongly-marked differences are brought into view. By Professor Owen the importance of the basal aspect has been especially dwelt upon, in his comparison of the skulls of the higher Quadrumana with that of Man, as more fully indicating the relative proportions and extent, and the peculiarities of formation, of different parts of the cranium, than any other method. By Dr. Pritchard, again, the importance of the front or facial view has been clearly shown, in regard, at least, to one variety of cranial conformation. Lastly, by Prof. Ret-zius, the length of the cranial cavity in proportion to its breadth is considered as the character of greatest importance; this being regarded by him as indicative of the relative development of the posterior lobes of the cerebral hemispheres, and of the degree in which they cover-in, or extend beyond, the cerebellum. As we have already seen, the superior development of these posterior lobes constitutes a marked difference between the cerebrum of Man and that of the higher Quadrumana ; and in this respect it would appear from the evidence afforded by cranial conformation *, that there is a marked difference among the several races of mankind.\nFig. 807.\tFig. i\nThe only method of comparison which can be fairly relied on, is that in which all the points of difference are taken into account; and as this has been done more fully by Dr. Prichard than by any other ethnologist, his arrangement will be taken as the chief guide in the present instance.\u2014If we were to select from a large collection of human crania, brought together from all quarters of the globe, those which differed most widely from each other, and which might, therefore, be considered as types of certain peculiarities of conformation, and if we were then to compare these more closely, so as to eliminate those which might be regarded as presenting mixtures or combinations of the most divergent types (just as in studying the solar spectrum, the optical investigator eliminates all the colours which can be generated by admixture, and leaves only the three primaries, red, blue, and yellow), we should find ourselves reduced at last to three forms, which would probably be the crania \u2014 ( 1 ) of a Negro of the Guinea coast, or of a Negrito of Australia, (2) of a Mongolian or Tun-gusian of Central Asia, or of an Esquimaux, or Greenlander, \u2014 and (3) of a native of Western or Southern Europe. The most marked feature of the first of these would be the projection of the jaws ; hence this type is called by Dr. Prichard the prognathous. That of the second would be the breadth and flatness of the face, which, with the narrowness of the forehead, gives to the facial aspect somewhat of a pyramidal form, which is the designation applied to this\n38.\tFig. 809.\nPrognathous Cranium of a native Australian of the Wiastern Port tribe. (From a specimen in the Museum\nof the Royal College of Surgeons.')\ntype by Dr. Prichard. The third form would not be distinguished by any particular fea-\n* The author would remark, however, that this evidence cannot by any means be implicitly relied on ; since the relative positions of the different parts of the encephalon may vary, without a corresponding alteration in their development, as is seen when the form of the cranium has been altered by compression. Of the fallacy of inferences drawn from an inspection of the cranium, as to the development of the different parts of the encephalon, we have an example in the assertion of Gall, that castration occasions atrophy of the cerebellum ; a statement which has been completely negatived by the observations of Leuret.\ntures so much as by an absence of the longitudinal projection of the first, or the lateral projection of the second, and by a general symmetry of the whole configuration, which maybe characterised as oval or elliptical; such being the form presented when the cranium is viewed either facially, basally, or vertically. The distinctive characters of these three types will now be more particularly considered ; and the European type may be conveniently taken as the standard of comparison, since it is in many respects intermediate between the two others; one of these departing from it in one direction, and the other in the opposite.","page":1320},{"file":"p1321.txt","language":"en","ocr_en":"1321\nVARIETIES OF MANKIND.\nOf the Prognathous type. \u2014 The most marked feature of the typical prognathous skull, as already remarked, is the prominence of the jaws, as seen in profile (fig. 807). It is this which gives to the features of the Negro and Australian their peculiar ugliness ; and it is on this that the difference of the facial angle between the Negro and the European chiefly depends. In both jaws we observe that the alveolar ridges project in such a manner, that the front teeth implanted in them meet at an angle, instead of being in the same, or in parallel planes, as in those skulls which are termed for the sake of distinction, orthognathic. Independently of the projection of the muzzle, however, there is an appearance of general elongation of the cranium from back to front, so that the anteroposterior diameter of the cranial cavity is greater in proportion to the lateral, than it is in the oval cranium. Thus the average length of ten Negro skulls measured by Pro-\u00bb fessorVan der Hoeven*, was 6-96 inches, while their average breadth was 5*11 inches; so that the relation of their length to their breadth was as P36 to POO. On the other hand, the average length of twenty European skulls was 7-04 inches, and their breadth 5'47 inches ; so that the relation of their length to their breadth was 1*30 to POO. But this difference (which is by no means great) seems to depend rather upon the relative narrowness, than upon the elongation, of the Negro cranium ; for it will be observed that its absolute length is less than that of the European, and that the difference in the dimensions of the two consists chiefly in the inferior breadth. The form of the whole cranium suggests the idea of lateral compression. The temporal muscles cover a large surface, and rise high upon the parietal bones ; and the zygomatic arch has a large opening, but this is given by a forward rather than a lateral projection of the cheek bones. Although the forehead very commonly recedes in the prognathous skull, this is by no means a constant character {fig. 810) ; even where it is high, however, it is seldom or never broad or full. The position of the foramen magnum has been affirmed to be, in the Negro, so far behind the nearly central place which it holds at the base of the European skull, as to constitute a marked character of approximation to the quadrumanous type ; but it has been shown by Dr. Prichard, that, when due allowance is made for the projection of the alveolar processes, the position of the foramen magnum in the Negro is as central as in the other races f, its anterior border being immediately behind the transverse line bisecting the antero-posterior diameter of the base of the cranium. The height of the Negro skull seems to be rather less than that of the European ; but there is a more marked inferiority in the capacity\n* Bijdragen tot de Natuurlijke Geschiedeniss van den Negerstam ; Leiden, 1842.\nf See Physical History of Mankind, vol. i. p. 290.\nof the Negro cranium, as shown by the length of the vault over the vertex, and in\nFig. 810.\nYoung Negro of Benguela. (After Rugendas.')\nthe circumference ; for the former averaged, in the measurements of Professor Van der Hoeven, 13-81 inches in the Negro, and 14-67 inches in the European ; whilst the average of the latter was 19-75 inches in the Negro, and 20-51 in the European. Although Professor Tiedemann attempted to prove *, by filling the cranial cavity with millet-seed, and then weighing the quantity which it was found to contain, that the capacity of the Negro\u2019s cranium is equal to that of the European\u2019s, yet, as Professor Van der Hoeven has pointed out, the average capacity of the Negro skulls thus examined by Tiedemann was about one-twentieth less than the average capacity of European skulls. On the other hand, the facial portion of the prognathous skull is relatively, and even absolutely larger. It has been usually described as being characterised by the large relative size of the parts subservient to the organs of the senses ; but although it certainly appears that both the anterior and posterior nares are wider than in the European, that the nasal cavity is altogether more capacious (so as to allow a more extended surface for the distribution of the olfactive nerve), and that the external auditory meatus is remarkably large, it does not appear that the same\u00bb holds good of the orbits, which, though sometimes larger, are sometimes smaller than in the average of Europeans, f\nThis prognathous type, although most remarkably developed among the Negroes of the Delta of the Niger, is by no means confined to them, nor to the African races in general, of which it is usually regarded\n* Das Hirn des Negers, mit dem des Europ\u00e4ers und Orang Outangs verglichen. Heidelberg : 1837.\nj- See Prichard, 9p. cit. p. 292.","page":1321},{"file":"p1322.txt","language":"en","ocr_en":"1322\nVARIETIES OF MANKIND.\nas characteristic. It is met with among inhabitants of various quarters of the globe ; but is nearly always associated with squalor and destitution, ignorance and brutality. Instead of following an agricultural or pastoral life, the people among whom it prevails are, for the most part, hunters, or inhabitants of low marshy forests, dependent for their supplies of food upon the chase, or upon the accidental produce of the soil, and but little advanced in any of the arts which are characteristic of civilisation. Such is the character of those aborigines of Australia, and of certain islands of the Polynesian Archipelago, amongst whom the prognathous type is presented almost, if not quite, as characteristically as among the Negroes of the Guinea coast.\nThe skulls of some of these inferior races have been asserted by Dr. John Neill* to present a division of the articulating surface of each occipital condyle into two facets, by a groove or ridge ; which appears to be the persistent indication of the fissure that originally separates the basi-occipital bone from the ex-occipitals. This character, however, is far from being constant in any one family. Thus it was only found in 30 out of 81 African crania; whilst it presented itself in only 4 pure Egyptian heads in Dr. Morton\u2019s collection, in 3 out of 105 skulls of\naboriginal Americans, and in none of the other 129 skulls of different nations whose history was well known. Thus, although more common among the African races than in the others, and marking in them (like the occasional persistence of the separate intermaxillary bone to a later period than usual) a less complete development, yet its presence in but little more than one-third even of the Negro-crania, and its occasional existence elsewhere, altogether destroy its title to be considered a mark of separation between different branches of the human family. The writer has looked for this character in at least twenty African crania, without once meeting with it ; the only skull which unequivocally presented it being that of a Tasmanian female, set. 14.\u2014Dr. Neill points out, also, that the lower boundary of the anterior nares in the Negro skull wants the sharp edge which is found in the higher races ; and that this, also, may be regarded as a retention of the f\u0153tal type. This character, however, is at least as strongly marked in Australians as in Negroes ; and an approximation to it is shown wherever there is a tendency to the prognathous conformation.\nOf the pyramidal type. \u2014 The most striking feature in this type of cranial conformation, which is best seen in the front and basal views (\u00dfgs. 811. 813.), is the lateral or out-\nFig.'\u00dfll.\nFig. 812.\nFig. 813.\nPyramidal Cranium of Mongolian race. ( From a specimen in the Museum of the Royal College of\nSurgeons.')\nward projection of the zygomatic arches ; this is principally due to the peculiar form of the malar bones, whose facial surface is very broad and flat ; but partly, also, to that of the zygomatic process of the temporal bone, which forms a large rounded sweep. From this peculiarity, in conjunction with the narrowness of the forehead, it results that lines drawn from the zygomatic arches, touching the temples on either side, instead of being parallel, or nearly so, as amongst Europeans, meet at no great distance over the forehead, so as to form, with the line joining their bases, a triangular figure. The upper part of the face being remarkably flat, the nose also being flat, and the nasal bones, as well as the space\n* American Journal of the Medical Sciences, Jan. 1850\u00bb\nbetween the eyebrows, being nearly in the same plane with the cheek-bones, the triangular space bounded by these lines may be compared to one of the faces of a pyramid. This, however, is by no means the most important peculiarity of this type ; for the shortness of the antero-posterior diameter of the cranium, in relation to the lateral, is, as pointed out by Professor Retzius, at least equally characteristic. Thus the average length of sixteen Laplander\u2019s skulls measured by him was about 6-90 inches, while the average breadth was as much as 5*78 inches ; making the proportion of the former to the latter no more than P20 to POO. The greatest longitudinal dimension among all these skulls was only 7'08 inches, while the greatest lateral extension was as much as 6*16 inches } thus reducing the proportion to P15 to POO.","page":1322},{"file":"p1323.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1323\nThe orbits in these skulls are large and deep ; and the peculiar conformation of the bones which surround them give to the aperture of the lids an appearance of obliquity, the inner angle being directed downwards (fig. 814).\nFig. 814.\nPortrait of one of the \u201cSiamese Twins.\u201d ( Taken in Paris in 1830.)\nThe whole face, instead of approaching the oval, as in Europeans, is of a lozenge-shape; and the greater relative development of the zygomatic bones, and of the bones of the face altogether, when compared with the capacity of the cranium, indicate in the pyramidal skull, as in the prognathous, a more ample development of the organs immediately subservient to sensation ; the lateral expansion being attended with a similar result in this respect, to that which is consequent upon the forward prolongation of the prognathous skulls. In the breadth of the lower jaw (fig. 813) a remarkable contrast will be noticed with that\nof the prognathous type (fig. 809). The greater part of the races representing the pyramidal type in a well marked degree, may be designated as pastoral nomades ; some of them wandering with their flocks and herds over the vast plains of high Asia, whilst others creep along the shores of the Icy sea, supporting themselves partly by fishing, but living in part upon the flesh of their rein-deer. As in the preceding case, however, the same type is encountered in a remote quarter of the globe, among tribes whose descent would seem to be altogether different, yet which closely corresponds with the nomadic races of high Asia as to the physical conditions under which they live ; namely, the Hottentots of South Africa, whose resemblance to Mongolians in cranial conformation, as well as in complexion, hair, and several other charac- \u2022\u00bb ters, is so striking as to have been noticed by all travellers familiar with both, and to have given rise to many speculations as to their possible blood-relationship. It will be hereafter shown, however, that there is no valid reason for separating the Hottentots from the general mass of the African nations ; and just as the Australians repeat the prognathous type at a distance from its chief centre, with a slight admixture of the pyramidal, so do the Hottentots in some degree repeat the pyramidal, with an admixture of the prognathous.\nOf the Oval or Elliptical type. \u2014 This form of cranial configuration at once approves itself to the educated eye, as distinguished by its symmetrical contour; neither the muzzle nor the zygomatic arches having an undue prominence, whilst, on the other hand, there is no appearance of flattening or compression. The cranium, in its fullest development, may be said to have the length of that of the Negro with the breadth of that of the Mongolian; and it is particularly distinguished by the lateral fulness, as well as by the elevation, of the forehead. This will be especially apparent on the comparison of fig. 815 with\nElliptical Cranium of European. ( From a specimen in the Museum of the Royal College of Surgeons.')\nthe corresponding view in figs. 807. and 811.; for in the former it will be seen that the breadth continues to increase above the orbits, and that the cranial vault is rounded and capacious ; whilst in the other two, the breadth diminishes rapidly, especially in the\nfrontal region, from the floor of the orbits upwards. The form of the zygomatic arches is such, that in the facial view they do not project laterally beyond the general boundary line, as they do in the Mongolian ; whilst the conformation of the jaws is such, that they","page":1323},{"file":"p1324.txt","language":"en","ocr_en":"132 4\nVARIETIES OF MANKIND.\ndo not form nearly as great a projection beyond the ellipse which would include the whole cranium and the greater part of the face, when seen in profile, as they do in the Negro. Owing to the more perpendicular direction of the alveolar processes, the front teeth of the two jaws are fixed in planes which are nearly or quite parallel to each other. The chief positive distinction of this form of cranium, is the large development of the cranial cavity, and especially the fullness and elevation of the forehead, in proportion to the size of the face; indicating the predominance of the intellectual powers over those merely instinctive propensities which are more directly connected with sensations. Among European nations, the Greeks have probably displayed the greatest symmetry in the form of the head, in the largest proportion of individuals ; but examples of equal symmetry might be found amongst any of the great group of nations now termed Indo-Atlantid\u00e6, and even, as will hereafter appear, in nations of entirely different descent. Nearly all of these have acquired a certain amount of civilisation, living by agriculture, and possessing settled habitations ; and among them, or among the offsets which have proceeded from them (as the people of the United States), we find all the nations which have been most distinguished for intellectual advancement, for the successful cultivation of the fine arts, and for the various improvements which distinguish the state of civilisation from that of barbarism.\nTo the foregoing general account of the three principal types of cranial conformation, may be added the results of the observations recently made public by Dr. Morton *, as to the capacity of the cranium of different races, measured after the manner adopted by Tiedemann (p. 1321.). The number of crania examined was 623; and they were derived from various races and families, as shown in the following table, which is here given without modification, although the writer (as will hereafter appear) is far from agreeing with Dr. Morton in the classification of these varieties which he has adopted.\nIt appears from this comparison, that the Teutonic race, and the nations chiefly derived from it, take the highest rank among those examined in regard to cranial capacity ; whilst the lowest is occupied, not by the Negroes, but by the Hottentots, the Australians, and the ancient Peruvians and Mexicans. The Negro race seems to be scarcely or not at all inferior in this particular to the Persians, the Bengalees, the Fellahs, the ancient Egyptians, the\"modern Fellahs, the Chinese, the Polynesians, and the North American Indians, It must be remarked, however, that the number of crania examined is too small, in some of the families, to admit of a fair average. This, however, it is most important to\n* Transactions of the American Medical Association, vol. iii. p. 57.\nTABLE\nShowing the Size of the Cranial Cavity in Cubic Inches.\n\t\t\t\t\t\n\t\u00b0 ^\t<8 r-J\t<\u00a3 ~\tc\t\u00d6\nRaces and Families.\t\tLarg Skul\tll CZ3\tcd CD \u00a7\tcd <D 3\nMODERN CAUCASIAN\t\t\t\t\t\nGROUP.\t\t\t\t\t\nTeutonic Family.\t\t\t\t\t\nGermans -\t18\t114\t70\t90\t)\nEnglish -\t5\t105\t91\t96\ty 92\nAnglo-Americans Pelasgic Family.\t7\t97\t82\t90\tJ\nPersians ) Armenians V -Circassians J\t10\t94\t75\t84\t\nCeltic Family. Native Irish -Indostanic Family.\t6\t97\t78\t87\t\nBengalees, &c. -Semitic Family.\t32\t91\t67\t80\t\nArabs\t-\t-\t- Nilotic Family.\t3\t98\t84\t89\t\nFellahs -\t17\t96\t66\t80\t\nANCIENT CAUCASIAN\t\t\t\t\t\nGROUP.\t\t\t\t\t\nPelasgic Family. '\t\t\t\t\t\nGr\u00e6co-Egyptians Nilotic Family.\t18\t97\t74\t88\t\nEgyptians\t55\t96\t68\t80\t\nMONGOLIAN GROUP. Chinese Family\t6\t91\t70\t82\t\nMALAY GROUP.\t\t\t\t\t\nMalayan Family\t20\t97\t68\t86\t| 85\nPolynesian Family -\t3\t84\t82\t83\t\nAMERICAN GROUP. Toltecan Family.\t\t\t\t\t\nPeruvians\t155\t101\t58\t75\t| 79\nMexicans Barbarous Tribes.\t22\t92\t67\t79\t\nIroquois\t'I\t\t\t\t\t\nLenape\tf Cherokee\tf\t161\t104\t70\t84\t>79\nShoshond, &c.J\t\t\t\t\t)\nNEGRO GROUP.\t\t\t\t\t\nNative African Family American-born Ne-\t62\t99\t65\t83\t>83\ngroes -\t12\t89\t73\t82\tJ\nHottentot Family -Alforian Family.\t3\t83\t68\t75\t\nAustralians\t8\t83\t63 \u25a0\t75\t\nobserve, that in the skull of largest capacity amongst the races whose average is the lowest, the cubical content is greater than that of the smallest skull among the highest. Thus we see that the largest native African skull contained 99 cubic inches; the largest American-born Negro, 89 cubic inches ; and the largest Hottentot and Alforian skulls, 83 cubic inches ; whilst, on the other hand, the smallest German skull contained but 70 cubic inches ; the smallest English, 91 inches ; and the smallest Anglo-American, 82 cubic inches. It is worthy of note, too, that the largest Negro skull possesses two inches more capa-","page":1324},{"file":"p1325.txt","language":"en","ocr_en":"1325\nVARIETIES OF MANKIND.\ncity than the largest Anglo-American. It is obvious, then, that no constant and impass> able line of distinction can be drawn on this basis, between any of the varieties of the human race.\nWe have now to inquire if the foregoing types of cranial conformation are sufficiently fixed and definite to furnish specific characters ; that is (1.), whether they are always clearly distinguishable from each other, or are connected together by a succession of gradations that renders it impossible to draw a distinct line of demarcation between them : and (2.) whether they are so invariably transmitted from one generation to another, where the purity of the race has been preserved, as to entitle them to be regarded as permanent and unalterable ; or are occasionally seen to vary in a succession of generations, so that a race loses more or less completely its original type, and assumes some other.\nWhen the cranial conformation of the whole Indo-Atlantic group of nations is carefully examined, it is perceived that although the elliptical type prevails among them, it is comparatively seldom seen in its perfection, and that a decided tendency is frequently seen towards one or other of the other types, or towards a mixture of the characters of all. Considerable variation is thus presented, not merely by the different races, but by different individuals of the same race. Thus in every large collection of English skulls, for example, crania would probably be found differing nearly as widely from each other in the proportion of length to breadth, as do the average of Negro and Mongolian crania ; whilst, again, some would exhibit more or less of approximation to the prognathous type, and others to the pyramidal. Of the former we have an example in fig. 818., and\nFig. 818.\nDolichocephalic Cranium of European. {From a specimen in the Museum of the Royal College of Surgeons.)\nof the latter inj%. 819.* ; the first of these skulls would certainly be placed, if the dimen-\n* Of these and most of the other figures of crania illustrating this article, the author would remark that, although every pains has been taken by the artist, it has been found impossible to express adequately on a small scale some of those nicer features of distinction, which are obvious enough in the skulls themselves.\nFig. 819.\nBrachycephalic Cranium of an Englishman. {From a specimen in the Museum of the Royal College of Surgeons.')\nsions of its cranial portion were alone regarded, in the \u201c dolichocephalic \u201d division of Professor Retzius, and only wants a little more elongation of the muzzle to be almost as prognathous as many African skulls ; whilst in the second, the breadth and front-flattening of the malar bones, with the inferior breadth of the forehead, show that it is obviously intermediate in character between the typical oval {fig. 815) and the typical pyramidal (fig. 811). So, again, if the so-called Mongolian group be surveyed, it will be found that the peculiarities of the pyramidal skull are often softened down, so as to present an approach to the elliptical form, sometimes through the whole of certain races, occasionally only in individuals. Here, too, there is a tendency to an admixture of types ; for we find among the American nations a very gradual transition from the truly pyramidal, such as is seen in the Esquimaux (fig. 820),\nFig. 820.\nCranium of Esquimaux. (From a specimen in the Museum of the Royal College of Surgeons.)\nto a form in which there is at least as great an admixture of the prognathous (fig. 822) ; whilst among the Chinese and other civilised nations of South-eastern Asia, we find so close an approximation to the oval type, that individuals are not unfrequently met with amongst them, whose skulls might be taken for those of Europeans.* So, again, if we\n* Such was the case, for example, with the Chinese skull, whose measurements are given by Professor Van der Hoeven (op. cit.) ; for in every one of its dimensions it varied less from the aver-","page":1325},{"file":"p1326.txt","language":"en","ocr_en":"1326\nVARIETIES OF MANKIND.\nFig. 821.\nFig. 822.\nCranium of Masacusi Indian. (From a specimen in the Museum of the Royal College of Surgeons.)\ntake a survey of the African nations, we find the prognathous type gradually softened down (so to speak) among them, until in some of the races of undoubted African descent, inhabiting the Nile valley, it merges into the oval. We have already noticed the curious admixture of the pyramidal and prognathous types which is seen in the Hottentot races ; and among the widely spread and isolated tribes by which Oceania is peopled, the same combination is exhibited in various degrees. For\nFig. 823.\nwhilst the skulls of the Malayan portion of the population are referable to the pyramidal type rather than to any other, those of many native Australians, and of various islanders designated as \u201c Pelagian Negroes,\u201d are almost purely prognathous, presenting but a very slight indication of a pyramidal tendency about the upper part of the face ; and between these there is every degree of gradation. Thus, in the Australian skull, delineated in figs. 823, 824, there is decidedly less prognathism\nFig. 824.\nCranium of Aboriginal Australian. (.From a specimen in\nthe Museum of the Royal College of Surgeons.)\nthan in that already described (fig. 808.) ; and in the skull of the Tahitian (fig. 825), with about the same amount of prognathism, there\nFig. 825.\nCranium of a Tahitian. ( From a specimen in the Museum of the Royal College of Surgeons.)\nis a considerably less degree of anteroposterior elongation ; in both these skulls,\nage of European skulls, than the latter varied from each other.\nmoreover, the upper part of the face, when seen in front, shows a decidedly pyramidal tendency. So, again, the Greenlanders are ranked by Professor Retzius among his Dolichoc\u00e9phales prognath\u0153, along with the Negroes and Australians, although \"the upper part of the face is often most characteristically pyramidal ; and even the Brachycephalic Tartars and Kalmuks are reckoned by him sufficiently prognathous to be separated from the Finns, Lapps, Turks, &c.\nThese facts, to which many more might be added, should be sufficient to convince every philosophic naturalist, who duly estimates what is required for the establishment of specific distinctions, that none such can be laid down among the different races of mankind, upon the foundation of cranial conformation alone. Those ethnologists who hold the doctrine of originally distinct stocks, which (they maintain) have continued to preserve their characteristic features through successive generations, have been obliged to admit, not three or five varieties of cranial conform-","page":1326},{"file":"p1327.txt","language":"en","ocr_en":"1327\nVARIETIES OF MANKIND.\nation, but twenty or thirty ; and as we increase our acquaintance with the physical characters of tribes at present little known, the number requires continual enlargement. And whether the types selected be few or many, they are always found to be connected by such a gradation of intermediate or transitional forms, that the well-marked boundary-lines which are necessary for the limitation of species, cannot be drawn with the slightest show of justification. It is not meant to be here asserted, that the absence of any such definite peculiarities of cranial conformation is of itself a sufficient reason for regarding the several races of mankind as specifically identical. On the contrary, as we have already seen, the genus Felis contains species as unmistakeably distinct as the lion and the tiger, between which there is no appreciable difference in cranial conformation All that we have a right to affirm is (1.), that the most extreme differences in the configuration of the skull, existing among the several races of men, are not greater than those which present themselves among races of domesticated mammals known to have had a common origin (e.g. those of the hog), and are not nearly so great as those existing among other races of mammals (as the various breeds of dog,) which are generally believed to have had a common origin; and (2.) that, as in the case of the domesticated races, the distinctive characters are by no means clearly marked out, but that those of the typical forms are softened down in intermediate gradations, so as to present a continuous series from one type to another, in which no such hiatus is left, as would justify the assumption of the specific distinctness of those types. This last fact of itself invalidates that supposition of the uniform transmission of physical characters from parent to offspring, on which the presumption of original distinctness mainly rests. For, on the theory of specific distinctness, all the descendants of the same parentage should repeat the characters of their ancestors without essential modification ; whereas we find, as a matter of fact, that the distinctive characters are perpetuated in their full intensity in only a small proportion of each race, and that in the great masses they are so shaded off as gradually to disappear. And this must be admitted, whatever types we may select as those representing the original species ; unless we go to the extreme length of selecting a distinct type for every distinguishable modification in the conformation of the skull, which would be a sort of reductio ad absurdum of the hypothesis.\nWe are thus led to the second branch of the inquiry, namely, whether there is adequate evidence that the cranial characters of the several races are really thus transmitted, with little or no modification, from generation to generation, or whether an actual passage may be effected in time from one type to another. Now, every one who has been accustomed to discriminate the varieties of cranial conformation which present them-\nselves within his own range of observation, must have noticed that not only between the parents and their offspring, but also among the different children of the same parentage, a considerable diversity not unfrequently exists. Further, on looking at the various individuals composing the ramifications of a particular family, it is frequently observable that they agree among themselves in some peculiarity of cranial configuration, which seems (from the evidence of portraits, busts, &c.) to have been transmitted downwards for centuries; and by this very character it may be separated from other families, which are in like manner distinguished for their respective peculiarities. Now, there can be no reasonable doubt that many such families had originally a common anc'esti'y, so that there must have been a time when each of these peculiarities first manifested itself in its own branch of the common stock ; for, if this be not admitted, we must suppose each of them to have descended from a distinct pair of \u201c protoplasts.\u201d It is obvious, then, that the question of possible modification is only one of degree ; and judging by the analogy of the domesticated races, by the amount of variation exhibited under circumstances not very dissimilar, and by the considerations already advanced (p. 1303. et seq.) respecting the probable sources of such variations, we should be prepared to expect that even the widest diversities which have been described, might have been occasioned by the sufficiently-prolonged influence of external causes acting upon a succession of generations. That such has been the case to a considerable extent, would appear in some instances from the direct evidence of history ; in other instances it would seem a necessary inference from the facts of philology; whilst in others, again, the two classes of evidentiary facts, neither of them sufficient in themselves, tend to confirm each other.\nOne of the most striking examples of this kind is afforded by the change in cranial conformation from the pyramidal to the elliptical, as well as in other characters, especially the length and abundance of the beard,\u2014. which has taken place among the Turks of Europe and Western Asia. These so closely accord in physical characters with the great bulk of European nations, and depart so widely from the Turks of Central Asia, that many writers have referred the former to the (so-called) Caucasian, rather than to the Mongolian stock. Yet historical and philological evidence sufficiently proves, that the Western Turks originally belonged to the Central Asiatic group of nations; with which the eastern portion of their nation still remains associated, not only in its geographical position, but in its language, physical characters, and habits of life ; and that it is in the western branch, not in the eastern, that the change has taken place. Some writers have supposed that this change might be explained as the result of an intermixture of the Turkish race with the inhabitants of the countries they","page":1327},{"file":"p1328.txt","language":"en","ocr_en":"1328\nVARIETIES OF MANKIND.\nhave conquered, or by the introduction of Georgian or Circassian slaves into their harems. But the cause suggested is plainly inadequate to the effect. For we know that in the Christian countries subjugated by the Turks, the conquering and the conquered races have been kept from properly domestic intermixture by mutual hatred, fostered by their difference in religion and manners ; and although Greek, Georgian, and Circassian females have been introduced into the harems of those who could afford to purchase them, yet any other modification which has been effected by their means must have had but an insignificant effect upon the mass of the population, since the pure Turkish descent of the poorer classes must have been but little interrupted, and universal experience shows that if the \u201c cross-breeding \u201d be not kept up, any new element introduced into a race speedily disappears. Even admitting that some modification may have been thus engendered, we cannot fairly attribute to it more than a very trifling share in the result ; since the effect of intermixture would simply have been to produce a hybrid or intermediate race, instead of the entire substitution of the elliptical type, which now manifests itself among the comparatively civilised Western Turks, whilst those which inhabit Central Asia, and retain the nomadic habits of their ancestors, have retained also their cranial conformation.\nAnother instance of the same modification is to be found in the Magyar race, which forms a large part of the population of Hungary, including the entire nobility of that country. This race, which is not inferior in physical or mental characters to any in Europe, is proved by historical and philological evidence to have been a branch of the great Northern Asiatic stock, which was expelled about ten centuries since from the country it then inhabited (which bordered on the Uralian mountains), and, in its turn, expelled the Slavonian nations from the fertile parts of Hungary, which it has occupied ever since. Having thus exchanged their abode, from the most rigorous climate of the old Continent, \u2014 a wilderness in which Ostiaks and Samoiedes pursue the chase during only the mildest season, \u2014 for one in the South of Europe, amid fertile plains abounding in rich harvests, the Magyars gradually laid aside the rude and savage habits which they are recorded to have brought with them, and adopted a more settled mode of life. In the course of a thousand years, their type of cranial conformation has been changed from the pyramidal to the elliptical ; and they have become a handsome people, with fine stature and regular European features, with just enough of the Tartar cast of countenance, in some instances, to recal their origin to mind. Here, again, it may be said that the intermixture of the conquering with the conquered race has had a great share in bringing about this change ; but a similar reply must be returned ; for the\nexisting Magyars pride themselves greatly on the purity of their descent ; and the small infusion of Slavonic blood, which may have taken place from time to time, is by no means sufficient to account for the complete change of type which now manifests itself. The women of pure Magyar race are said by good judges to be singularly beautiful, far surpassing either German or Slavonian females.\nA similar modification, but less in degree, appears to have taken place among the Finnish tribes of Scandinavia. These may be almost certainly affirmed to have had the same origin with the Lapps* ; but whilst the latter retain (although inhabiting Europe) the nomadic habits of their Mongolian ancestors, the former have adopted a much more settled mode of life, and have made considerable advances in civilisation, especially in Esthonia, where they assimilate with their Russian neighbours. And thus we have in the Lapps, Finns, and Magyars, three nations or tribes, of whose descent from a common stock no reasonable doubt can be entertained, and which yet exhibit the most marked differences in cranial characters, and also in general conformation, the Magyars being as tall and well-made, as the Lapps are short and uncouth.\nAnother instance of the same kind, which is still more remarkable if it can be entirely substantiated, is the conversion of the Georgian and Caucasian nations from the pyramidal or Mongolian to the elliptical or Indo-European type. The designation Caucasian seems to have been given to the latter on the following most unsatisfactory ground. \u201c Blumenbach had a solitary Georgian skull ; and that solitary skull was the finest in his collection, that of a Greek being next. Hence it was taken as the type of the skull of the more organised divisions of the species. More than this, it gave its name to the type, and introduced the term Caucasian.\u201d f Now the fact is, that the Georgian and Circassian\n* This proposition, which is supported by the almost unanimous voice of the learned historians of Germany, was assailed a few years since by Profs. Nilson, Retzius, and other Scandinavian savans, who endeavoured to prove by arch\u00e6ological and anatomical evidence, that the origin of the Finnish race was not the same with that of the Lapps, but that it was more nearly connected with the Swedish nation, which is a northern branch of the great Indo-European family. Much of the arch\u00e6ological evidence adduced, however, is capable of receiving a directly opposite interpretation ; and the philological evidence, derived from the comparative study of the Finnish and Swedish languages, shows that the basis of the former was essentially peculiar to it, and that the nature of the modification which it has undergone from Swedish influence, indicates a considerable advance in civilisation previously to the subjugation of the race by foreign invaders. Dr. Latham, the latest authority on this subject, expresses himself very decidedly as to the affinity of the Finns, Lapps, and Hungarians, whom he ranks with the Yoguls, Ostiaks, and Permians, as off-sets of the Ugrian branch of the Turanian (Mongolian) stock.\u2014See his Natural History of the Varieties of Man, p. 100.\nt Latham, op. cit. p. 108.","page":1328},{"file":"p1329.txt","language":"en","ocr_en":"1329\nVARIETIES OF MANKIND.\nnations are composed of an assemblage of tribes inhabiting a mountainous country, speaking languages almost unintelligible to each other, and remarkably isolated from the nations which inhabit the countries bordering on theirs. The beauty of form and feature, and the delicacy of complexion, which characterise individuals and families among these\nFig. 826.\nPortrait of a young Circassian, belonging to the suite of the Persian Ambassador.\t(From a portrait\ntaken in Paris by M. A. Colin.')\ntribes, are well known (fig. 826.) and have led to a regular consignment of the youth of both sexes to the Turkish market, the females to be introduced into the harems, whilst the youths are valued for their superior energy and intelligence, and are frequently adopted as sons. But these attributes are for the most part confined to the families of the chiefs; and they are carefully cherished by exemption from labour, and by seclusion from undue exposure. The common people, who are engaged in the cultivation of the soil, are described by travellers as being for the most part coarse and unshapely.\u2014Now from a careful comparison and analysis of the languages of these races, Dr. Latham and Mr. Norris have independently arrived, on different grounds (the one from the words and the other from the grammar), at the same result ; namely, that they are aptotic, or destitute of inflexions, like the Chinese ; and that the people must have been of Mongolian origin, but separated from the common stock at a very early period ; the perpetuation of the low development of their language being favoured by the peculiar characters of the VOL. IV.\ncountry in which they located themselves, whilst these same characters tended to modify their physical conformation. For the area which they occupy is at once temperate, mountainous, and wooded ; \u201c in other words,\u201d as Dr. Latham remarks, \u201c the reverse of the true Mongol areas.\u201d And thus, if this view should be confirmed, we must regard the very people which has been selected as furnishing the type of the most perfect conformation, as an improved race of a decidedly inferior stock.\nThe Negro type is one which is not unfre-quently cited as an example of the permanence of the physical characters of races, and especially of types of cranial conformation. The existing Ethiopian physiognomy is said to agree with the representations transmitted to us from the remotest times in Egyptian pictures ; and this physiognomy, it is further maintained, continues to be transmitted unchanged from parent to child, even where the transportation of a Negro population to temperate climates and civilised associates (as in the United States of America) has entirely changed the external conditions of their existence. Now it is perfectly true that the Negro races which continue to inhabit their original localities, and maintain their barbarous habits of life, retain the prognathous type ; and this is precisely what we should expect. But it is not true that no modification has taken place in them, either under the influence of civilisation, or from a change in the physical conditions of their existence. For the most elevated forms of skull occurring among the African nations, are found in those which have emerged in a greater or less degree from their original barbarism ; their civilisation having been due to external influences brought to bear upon them. We shall hereafter see that there is strong evidence that even the Syro-Arabian or Semitic nations may be referred to the African stock ; at any rate, there are numerous tribes in the interior of Africa, whose affinity with the true Negroes cannot be disputed, and which yet present a far superior cranial organisation ; so that we must either regard the one form to be the result of improvement, or the other to have preceded from degeneration. In regard to the transplanted Negroes, it is obvious that the time which has elapsed since their removal, is as yet too short to justify us in expecting any considerable alteiation in cranial configuration. Many of the Negroes now living in the West Indian islands are natives of Africa ; and a large proportion of the Negro population, both there and in the United States, are removed by no more than one or two descents from their African progenitors. The climate, too, of the southern states of the North American Union, as of the West Indies, is not very different from that of the Guinea Coast, in regard to temperature ; and the low undrained character of much of the soil which they are employed in cultivating, still further tends to keep up the correspondence. Still, according to the concurrent","page":1329},{"file":"p1330.txt","language":"en","ocr_en":"1330\nVARIETIES OF MANKIND.\ntestimony of disinterested observers, both in the West Indies and in the United States, an approximation in the Negro physiognomy to the European model is progressively taking place, in instances in which, although there has been no intermixture of European blood, the influence of a higher civilisation has been powerfully exercised for a lengthened period. This is particularly the case with Negroes employed as domestic servants. Dr. Hancock, a most intelligent physician of Guiana, even asserts that it is frequently not at all difficult to distinguish a Negro of pure blood, belonging to the Dutch portion of the colony, from another belonging to the English settlements, by the correspondence between the features and expression of each, and those which are characteristic of their respective masters. This alteration, too, is not confined to a change of form in the skull, or to a diminution in the projection of the jaw ; but it is also seen in the general figure, and in the form of the soft parts, as the lips and nose. And the writer has been informed by Sir Charles Lyell, that during his recent tour in America, he was assured by numerous medical men residing in the slave states of the North American Union, that a gradual approximation is taking place in the configuration of the head and body of the Negroes to the European model, each successive generation exhibiting an improvement in these respects. The change is most apparent in such as are brought into closest and most habitual relation with the whites (as by domestic servitude), without any actual intermixture of races, which would be at once betrayed by the change of complexion, and by the more strongly marked indications of hybridism.\nIt is more easy to imagine that a pyramidal or a prognathous cranium can be metamorphosed into an elliptical one, than that either of the two first-named forms can be converted into the other. Yet very strong evidence is furnished by philological considerations, that the Hottentot races constitute a branch of the common African stock ; and the approximation which their skulls present to the pyramidal type cannot be for a moment attributed to intermixture with any Mongolian race. On the other hand, among the inhabitants of Oceania, there are many races which present, more or less decidedly, the prognathous type ; and this sometimes associated with woolly or \u201c frizzled,\u201d sometimes with long and straight hair. Yet there is strong philological evidence for regarding these as descendants of colonists who spread themselves (probably by various lines of migration) from south-eastern Asia, and who carried to the various islands of the vast Malayo-Polynesian Archipelago, the pyramidal type more or less softened down. On no other hypothesis can the extraordinary community in the fundamental elements of their languages be accounted for, the tribes which use them being in a state of complete isolation from each other. Where, as is\nfrequently the case, the same island or group is peopled by two or more races, having different physical characters, it is always found that the greatest tendency to the prognathous type shows itself among those which appear to have longest dwelt there in a state of barbarism ; and that it is most strongly marked, when, to other degrading agencies, that of a low and marshy soil has been added.\nEven the elliptical type, as already remarked, may occasionally present indications of degradation towards one of the others. Want, squalor, and ignorance, have a special tendency to induce that diminution of the cranial portion of the skull, and that increase of the facial, which characterise the prognathous t}>pe ; as cannot but be observed by any one who takes an accurate and candid survey of the condition of the most degraded part of the population of the great towns of this country, but as is seen to be preeminently the case with regard to the lowest classes of Irish immigrants. A certain degree of regression to the pyramidal type is also to be noticed among the \u201c nomadic \u201d tribes which are to be found in every civilised community. Among these, as has been remarked by a very acute observer, \u201c according as they partake more or less of the purely vagabond nature, doing nothing whatsoever for their living, but moving from place to place, preying on the earnings of the more industrious portion of the community, so will the attributes of the nomade races be found more or less marked in them ; and they are all more or less distinguished for their high cheek bones and protruding jaivs * thus showing that kind of mixture of the pyramidal with the prognathous type, which is to be seen among the most degraded of the Malayo-Polynesian races.\nIt has not been pointed out, so far as the writer is aware, by any ethnologist, that the conformation of the cranium seems to have undergone a certain amount of alteration even in the Anglo-Saxon race of the United States, which assimilates it in some degree to that of the aboriginal inhabitants. Certain it is, that, among New Englanders more particularly, a cast of countenance prevails, which usually renders it easy for any one familiar with it to point out an individual of that country in the midst of an assemblage of Englishmen ; and although this may chiefly depend upon the conformation of the soft parts, yet there is a certain sharpness, and an angularity of feature about a genuine \u201c Yankee,\u201d which would probably display itself in the contour of the bones. So far as the writer\u2019s observation has extended, there is especially to be noticed an excess of breadth between the rami of the lower jaw, giving to the lower part of the face a peculiar squareness (something like that which is shown in Jig. 82]), that is in striking contrast with the tendency to an oval\n* London Labour and the London Poor; by Henry Mayhew, p. 2.","page":1330},{"file":"p1331.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\t1331\nnarrowing which is most common among the inhabitants of the \u201c old country.\u201d And it is not a little significant, that the well-marked change which has thus shown itself in the course of a very few generations, should tend to assimilate the Anglo-American race to the aborigines of the country ; the peculiar physiognomy here adverted to, most assuredly presenting a transition, however slight, towards that of the North-American Indian.\n2.\tConformation of the Pelvis. -\u2014 Certain differences in the pelvis have been thought to be characteristic of particular nations or groups of nations. According to Professor Vrolik *, who was the first to take up the enquiry systematically, the difference between the male and the female pelvis is much more strongly marked in the Negro than in the European. The pelvis of the male Negro, in the strength and density of its substance, and in the form of its component bones,resembles the pelvis of a wild beast ; while, on the contrary, the pelvis of the female of the same race combines lightness of substance and delicacy of form and structure. Notwithstanding this delicacy of conformation, it is considered by Professor Vrolik to present characters which indicate an approximation to that of the Quadrumana ; for the ossa ilii are unusually vertical in their direction, and the highest part of their crest is situated immediately above the posterior and upper tuberosity, instead of being midway between the anterior spine and posterior tuberosity ; the length of the an-tero-posterior diameter at the brim is very great in proportion to the transverse diameter; the sacrum is narrower, and the angle beneath the pubic articulation more acute ; the whole pelvis is longer ; but the diameters at the outlet are not sensibly different from those of the European pelvis. The conformation of the pelvis in the female Hottentot, who died in Paris in 1815, is considered by Professor Vrolik to present a still wider departure from the European form, and a correspondingly nearer approximation to the quadrumanous ; the ilia are so vertical in their direction, and are so much lengthened upwards, as to rise above the level of the middle of the fourth lumbar vertebra. In the Javanese (Malay), the pelvis is distinguished by its smallness, its peculiar lightness of substance, and the circular form of its upper aperture; the promontory of the sacrum projects very little ; and the ischiadic spines are remarkably turned inwards.\nA more extended comparison of the pelvis of different races, however, has been made by Professor M. I. Weber ; who classifies all the varieties he has met with under the four following heads, which are named according to the form of the aperture of the brim : \u2014\n1.\tThe oval, in which the aperture has somewhat the form of an egg, the narrowest end of the ellipse being at the symphysis\n* Platen behoorende tot de Beschowing van het Versehet der Bekkens in onderscheidene Volkstana-men. Amsterdam ; 1826.\npubis : but the antero-posterior diameter is shorter than the transverse.\n2.\tThe round, in which the antero-posterior and transverse diameters are nearly equal.\n3.\tThe square, or four-sided ; in which the sides, especially that formed by the os pubis, are flat and broad, so that the aperture forms nearly a perfect square ; the transverse diameter is greater than the antero-posterior.\n4.\tThe oblong ; in which the sides are compressed, and the transverse diameter is consequently the least ; the sacrum is narrow ; and the angle at which the ossa pubis unite is very acute ; the ossa ilii are high, and nearer to each other than in the previous forms.\nNow, if any attempt be made to assign any one of these forms of pelvis to a particular nation or group of nations, it fails in toto ; because, although particular types are more common than others in each principal; variety, yet each kind may present itself in other individuals of the same race. Thus, the oval type is most common in the European, where it is in accordance with the oval form of the skull ; but round, square, and wedge-shaped pelves also present themselves occasionally ; and the oval form is met with again in the pelvis of a Botacudo, a people reputed to be the most savage of all the American nations. The round type seems most frequent among the American and Malayan nations ; but it has been observed by Weber not merely in the European, but in a Negress, and in a female Hottentot. The square form seems most common among the nations with decidedly pyramidal skulls, especially the Northern Asiatics ; but it occurs also in Europeans, and in the mixed race of Mestizos. Finally, the oblong pelvis is most common among the African races, and is conformable to the elongated shape usually possessed by their crania ; but it has been observed also among Europeans and Botocudos.*\u2014The writer\u2019s own observations, so far as they extend, confirm this view, as to the conformity between the shape of the pelvis and that of the skull; which renders it probable that the influences which affect the latter will modify the former also.\n3.\tConformation of other parts of the she-leton. \u2014 Other characters have been at different times adduced, as showing that the Negro and other degraded races are really to be considered as forming a distinct group, intermediate between the higher specimens of humanity and the superior apes. Of these, the most important will be now inquired into. It was maintained by Soemmering, and since his time very generally believed, that the position of the foramen magnum in the Negro skull is intermediate between that which it holds in man, and that which it presents in the anthropoid Simi\u00e6; but this, as already shown, is a mistaken view of the case ; for,\n* Die Lehre von den Ur- und Kacenformen der Schaedel und Becken des Menschen, von Dr. M. I. Weber. D\u00fcsseldorf: 1830.\n4 a 2","page":1331},{"file":"p1332.txt","language":"en","ocr_en":"1332\nVARIETIES OF MANKIND.\nif we make allowance for the projection of the jaws, and consider only its relation to the cranial portion of the skull, the position of the foramen magnum is found to be the same in the Negro as in the European ; whilst in the adult forms of the highest apes, as shown by Professor Owen, it is removed very much further back, although in the young it is nearer the centre of the base. Again, it was stated by White, and has been generally believed, that the length of the fore arm in the Negro is so much greater than in the European, as to constitute a real approximation to the quadrumanous type. But an extended comparison proves, that only a very slight difference exists between the average length of this part in the two races ; and that this difference is by no means greater than that which may be observed on comparing the individuals of which any single race or nation is composed. On the other hand, a constant and decided difference exists, as already pointed out, between all races of mankind and the highest Quadrumana. Again, it has been supposed that the Negro races are characterised by that peculiar curved form of the bones of the leg, which gives rise to what is popularly designated as the \u201ccucumber-shin;\u201d also by the great elongation of the heel; and by the\nbreadth and flatness of the foot. Such peculiarities are doubtless to be observed among individuals, and may be said to be general among the inferior Negro tribes ; but they are scarcely discoverable in the higher, among which a remarkable degree of symmetry in the conformation of these parts is often discernible. And it should not be forgotten that the increased development of the heel, and the flattening of the foot, are characters which remove the Negro from the anthropoid apes, still more widely than the European, instead of being a character of approximation. It has been further asserted, that the inferior races generally are characterised by slender, elongated, and mis-shapen limbs, and by a great deficiency of physical power, as compared with Europeans. This is undoubtedly true of such as are habitually ill-fed, and live in a condition of squalid ignorance. But it is scarcely less true of those individuals among any of the higher races, who are subjected to the same conditions. Thus, although the extreme of this condition is witnessed among the Bosjesmans and Alfourous, yet approaches to it may be seen among the lowest grades of the population in the most civilised nations. The accompanying figure (fig. 827), which represents a group of Australians looking at a\nFig. 827.\nmirror that had been presented to one of their tribe, who had been clothed by the sailors of the Astrolabe, might almost be supposed to be intended for a set of half-starved Irish. Moreover, among the races which are considered to exhibit this character in its most decided form, individuals are often found, who, having grown up under more favourable conditions,\nexhibit the most complete symmetry, and the greatest vigour. Such, for example, are not wanting among the Australian races, which present a remarkable variety in this particular. Among most savage races, the families of the chiefs exhibit a higher grade of physical development than the ordinary population ; and this is quite sufficiently accounted for by the","page":1332},{"file":"p1333.txt","language":"en","ocr_en":"1333\nVARIETIES OF MANKIND.\ndifference of the conditions under -which they live, especially in regard to food.\nIt may be safely asserted, then, that on none of the foregoing characters can specific distinctions be justly based, since none of them possess the constancy which is required to give them such a rank ; and those which are most strongly marked in particular cases, are such as can be proved to be most liable to modification from external conditions.\n4. We next have to inquire into the distinctions founded upon the Colour of the Skin; which, at first sight, appear to present a degree of constancy that gives them a strong claim to be regarded as permanent, and therefore as valid distinctive characters between the several races of mankind. The hue of the Skin, it is now well known, exists in the epidermis only, and depends upon the presence of pigmentary matter in the ordinary cells of that part. What was formerly known as the \u201crete mucosum,\u201d or \u201c rete Malpighii,\u201d and described as a distinct colouring layer between the epidermis and cutis vera, is now known to be nothing else than the newest and softest layer of epidermis. There is no structure (as has been affirmed by some anatomists) in the skin of the dark races, that is at all peculiar to it ; the very same dark matter being found in particular spots of the fairest skins, as in that of the areola surrounding the nipple during pregnancy. The following is the description of the structure given by Messrs. Todd and Bowman, the accuracy of which the author can fully confirm from his own observation :\u2014\u201c However various in colour and hue, the colouring matter always consists of oblong or oval grains of extreme minuteness (1-20,000th of an inch in their long diameter), and occupying the interior of some of the epidermic particles. In the Negro it is accumulated in enormous quantity, and completely envelopes the nuclei immediately resting on the cutis. On examining a vertical section of the whole cuticle, we find the colouring matter gradually diminishing as we approach the surface ; and it is most clear that there is no true line of demarcation between the two portions. We may observe the colour of the rete mucosum deeper at points ; and a greater proportionate depth of colour is traceable over such points, through all the layers, as far as the surface ; we may even discern a sort of stream of coloured grains advancing towards the surface. Hence there can be little doubt that the decrease of colour in the superficial laminae is due to that chemical change which has been described as gradually taking place in the interior of the epidermic particles.\u201d*\nStill it might be affirmed that the presence of a large amount of pigmentary matter, of a\n* Physiological Anatomy, vol. i. p. 415. The Rete Malpighii is represented by Prof. K\u00f6lliker as more distinct from the superjacent layers; but the writer has not been able to satisfy himself of the accuracy of the descriptions and figures of Prof. K\u00f6lliker on this point. See his Microskopische Anatomie ; Zweiter Band, \u00a7\u00a7 14\u201422.\npeculiar tint, in the substance of the epidermis, constitutes a typical character of particular races, even though there be no distinct pigmentary layer ; since spots and patches of colour are often admitted as specific distinctions among the lower animals. Thus, for example, it has been maintained that the fair and ruddy Saxon, the jet-black Negro, the olive Mongolian, and the copper-coloured North-American, have as good a claim to be ranked as distinct species, on the score.of the uniform transmission of their respective hues from generation to generation, as have many races of Lepidoptera (for example) which are regarded by naturalists as specifically diverse on account of the distribution of colour in the scales of their wings. But as the validity of the specific distinction among these last entirely rests upon the intransitive nature of the character, the several individuals that constitute either race exhibiting no approximation towards those of the other, and the successive generations repeating the respective peculiarities of each race with great exactness, we must apply the same test to the Human races.\nNow, if we take any one of those groups of nations which are usually regarded as altogether constituting a race, such as the (so-called) Caucasian, the Mongolian, the African the American, or the Polynesian, it will be found that the greatest diversity of complexion exists within its limits. Thus, among the \u2018 Japetic \u201d races, \u2014 which are characterised by the possession of the oval type of cranial conformation, and whose languages are so clearly traceable to a common stock, that no philologist now questions the identity of their origin,\u2014we find every range of colour, from the fair Saxon and Celtic nations, to the deep brown of the Indian Brahmin.* Among the Syro-Arabian, or \u201c Semitic\u201d races, again, which are spread over South-western Asia and Northern Africa, and which are connected by close affinity of language, there is an equal variety of complexion. All travellers who have visited the high lands of Arabia, represent the inhabitants as having light complexions, their eyes being often blue, and their hair red. The Arabs near Muscat are of a sickly yellow hue ; those of the neighbourhood of Mecca are of a yellowish brown, while those of the low countries bordering on the Nile are almost jet-black. So, again, among the various tribes referable to the same stock, which inhabit the Atlantic region of the north of Africa, similar differences of complexion prevail; for whilst those wdiich inhabit the higher lands and mountain passes, such as the tribe of Mozabi among the Kabyles, are remarkably fair, those which dwell in the more level parts of the country are swarthy,\n* The hue of many of the races of Lower India is as black as that of any Negroes ; but there is a doubt (as will hereafter appear) as to their origin. If not Indo-Atlantic, however, they are Mongolian ; and the peculiarity is at least as striking, when they are viewed as off-sets from the latter stock, as when they are considered as appertaining to the former.","page":1333},{"file":"p1334.txt","language":"en","ocr_en":"1334\tVARIETIES OF MANKIND.\nand some of the Tuaryks which inhabit the borders of the Great Desert, are as black as the darkest Negro.\nAmong the proper African nations, it may be supposed that no such variety would embarrass us; blackness, with a reddish or yellowish tinge, being accounted the universal hue of the Ethiopian race. But this notion is chiefly7- founded upon the complexion which prevails in a very small part of the great African continent ; and no fact is really better established, than that of the great diversity of complexion which prevails among its different inhabitants. Thus, among some of the Kaffir tribes,\u2014which often possess high foreheads and prominent noses,\u2014 light brown complexions, and reddish hair are often met with ; yet there is every reason for the belief that they are of the same stock with the Negroes of the Guinea coast, and intermediate gradations in complexion are presented by the nations which occupy an intermediate geographical position. There are tribes even upon the gold and slave coasts, which are considerably lighter than ordinary Negroes. Moreover, the Hottentot has a large admixture of yellow in his complexion, whilst the Fulahs of Central Africa are of a dark copper colour. The African tribes which border on the Red Sea, and which seem to constitute the link of transition between the Ethiopian and the Semitic races, present every grade of colour, from the deep black of the Negro to the swarthiness of the lighter Arabs, notwithstanding that there is no reason to believe these characters to have been acquired by the intermixture either of an Ethiopian stock with Arabs, or of an Arab stock with Ethiopians. There is strong ground for the opinion, as we shall see hereafter, that the ancient Egyptians, whose complexion (as represented by their own artists) seems to have been of a red copper or light chocolate colour, were so closely allied to the proper African nations, that the origin of both must have been the same.\u2014The complexion of the African nations, then, wants that character of uniformity, which is required to distinguish it from that of other branches of the human family ; and a marked tendency to assimilation is exhibited in the hues of the African and of the Semitic races inhabiting similar localities, a fact whose full significance will appear hereafter.\nOn instituting a similar comparison between the complexions of the various branches and off-sets of the Mongolian race, it will appear that, although an admixture of yellow is one of its most constant characters, yet this may co-exist with other shades, and may even disappear altogether. Thus, in the remains of the aboriginal tribes of India still existing in the hilly regions of the north, in the Dekhan, and especially in Ceylon, all of which appear, from the characters of their language, their peculiar customs, and their traditions, to be descendants of the Mongolian rather than of the Japetic stock, we find a variety of shades of complexion,\nand this within the limits of the same people. For example, the Cinghalese are described by Dr. Davy as varying in colour from light brown to black ; the prevalent hue of their hair and eyes is black, but hazel eyes and brown hair are not very uncommon ; grey eyes and red hair are occasionally, though rarely, seen, and sometimes the light blue or red eye, and light flaxen hair of the Albino. Dr. Davy, in describing such a one, remarks that her complexion would scarcely be considered peculiar in England, certainly not in Norway ; for her eyes were light blue, and not particularly weak, her hair of the colour that usually accompanies such eyes, and her complexion rather rosy. This tendency towards a fair and even florid complexion, with light eyes and bushy hair, can be traced in several other nations of the same type, such as the Mantchoos in China, and also among the Chinese themselves. On the other hand, the hardy Samoiedes, Tungusians, Kamschatdales, and others, living on the borders of the Icy Sea, have a dirty brown or swarthy complexion.\nIf we pass on to the Oceanic races, we find that any attempts to employ complexion as a means of distinguishing them from other primary stocks, must utterly fail, so great and numerous are the diversities. In almost every group of islands in the great Oceanic area, the natives differ in complexion from those of other groups ; thus the Malays of the Eastern Archipelago, who resemble the Chinese in features and general conformation, are of a darker colour, retaining, however, a yellow tinge in their complexion ; this tinge comes out very strongly in the natives of the Caroline Islands, whose aspect is decidedly Mongolian, and whose complexion is of a citron hue, becoming brown by exposure; the Tahitians and Marquesans, especially in the families of their chiefs, which are secluded from the wind and the sun, exhibit a clear olive or brunette complexion, such as is common among the nations of Southern Europe ; the Hawaii, or Sandwich Islanders, are somewhat darker ; while of the new Zealanders and Ombai Islanders, some are comparatively fair, while others are dark or almost black. Besides these, however, Australia, New Guinea, and some of the neighbouring islands are more or less exclusively peopled by tribes bearing a close resemblance in complexion and aspect to Negroes, whose precise relation to the Malayo-Polynesian races it is difficult to determine. There is, however, such a complete transition from one type to the other, presented by the natives of different localities among whom there is no reason to suppose that any intermixture has taken place, and the differences are such between the higher and lower castes of even the same tribe, that all intelligent persons who have long resided among the islands of the Pacific, under circumstances favourable to accurate investigation, appear to have come to the conclusion,\u2014that none of those characters on wdiich some observers have relied, as being","page":1334},{"file":"p1335.txt","language":"en","ocr_en":"1335\nVARIETIES OF MANKIND.\nstrongly marked in the individuals whom they have happened to see in the course of their brief visits to different localities, can be relied on as general expressions of the attributes of particular races. So that if colour be once adopted as a test of separate origin, we must suppose that tribes speaking the same language, having the same customs and traditions, and closely allied in general conformation, sprang nevertheless from ancestors who had no relation to one another ; and a distinct pair must be assigned to almost every island or group of islands, and, in some instances, even two or more pairs to a single island.\nLastly, in regard to the American nations, it is sufficient to remark, that the appellation \u201c red men,\u201d is by no means characteristic of them as a whole ; for not only are tribes elsewhere found at least equally deserving of it, but it is not applicable to a large proportion of the population of the New Continent. For although some of the North-American Indians are copper-coloured, some are as fair as many Europeans ; others are of a brown or yellow complexion ; and others nearly, if not quite, as black as African Negroes. Similar diversities exist among the aborigines of South America. Here, also, therefore, we should be forced into the supposition of a large number of primitive stocks in near vicinity to each other, were so much authority to be attributed to colour, as to allow it to rank as a sufficiently distinctive character for the specific discrimination of any of the races of mankind.\nWe have now to examine if the peculiarities of colour seen among different races can be attributed with any considerable degree of probability to external agencies ; and the evidence bearing on this question may be considered under two heads, namely (1.) the constancy of the relation between the habitual operation of particular climatic influences and particular shades of complexion ; and (2.) the historical evidence of an actual change of complexion, in races or tribes that are known to have migrated from one locality to another of a different character, or to have changed their mode of life.\nNow, the general relation between climate and complexion is apparent on the most cursory survey of the facts. It is only in the intertropical regions, and in the countries bordering on them, that we meet with the greatest depth of colour in the skin ; and all the nations inhabiting the level parts of those regions exhibit a tendency towards a very dark hue. On the other hand, the colder temperate regions are the residence of the fair races. And the intermediate countries exhibit the transition from one complexion to the other, as we see on passing from Central Africa, through Northern Africa and Southern Europe, to Northern Europe. Now this, if we had no evidence to the contrary, might fairly be held to indicate that each race had been created with especial reference to a particular climate ; the principal difficulty in the way of\nsuch a supposition, being the great number of different races whose separate origins it would be necessary to assume, if it be held that each has uniformly exhibited the complexion which it now possesses. But it is most remarkable that elevation above the sea-level is found to have the same uniform relation to the human complexion, that it has to vegetation. For as we find the plants of temperate or even arctic regions on the sides of inter-tropical mountains, so do we notice that high mountains and table-lands of great elevation are almost uniformly inhabited by people, of lighter hue than those of the surrounding country, however close may be their affinity ; whilst low and level countries, especially those which border on the sea, are as commonly tenanted by people of an unusually dark colour. Thus the deepest hue among the African races is to be found among, the negroes of the swampy plains of the Guinea coast; yet there are several instances, in which nations residing at no great distance from these, but at a higher level, are comparatively light, although their ancestry is undoubtedly the same. In Northern India, again, the lightness of complexion among the inhabitants of the mountains and table-lands is almost exactly in accordance with the elevation at which the tribe has been accustomed to dwell ; and some of these present complexions of almost European fairness. On the other hand, among the tribes that wander along the shores of the Icy Sea, their proximity to the ocean, together with their habitual exposure, seem to compensate in some degree for their distance from the equator ; so that their hue is much swarthier than that of the more civilised inhabitants of Northern Europe. The influence of seclusion from exposure, in lightening the hue of the skin among the higher castes of various tropical races, has been already remarked upon ; and another indication of the importance of this influence is derived from the concurrent though independent observations of M. D\u2019Orbigny and Sir R. Schomburgh upon the people of the New World, both having remarked that those tribes which live under the damp shade of dense and lofty forests, are much fairer than those which are freely exposed to solar light and heat in dry and open spaces. The influence of continued exposure to the solar rays is often strongly marked in individuals of the lighter races ; those who are naturally of a \u201cbrunette\u201d complexion becoming swarthy, whilst in those who are naturally fair or \u201c blonde,\u201d there is a tendency either' to a general reddening or \u201c tanning\u201d of the skin, or to the development of \u201c freckles,\u201d which are nothing else than local collections of pigmentary matter, usually of a reddish-yellow colour. In such cases, the parts of the body which are habitually kept covered retain their original fairness.\nSeeing, then, that continued exposure to the solar rays has such a marked effect upon the complexion of individuals who are subjected to it, we should be led to expect, upon\n4 q 4?","page":1335},{"file":"p1336.txt","language":"en","ocr_en":"1336\nVARIETIES OF MANKIND.\nthe principles already laid down, that this effect would be increased when the cause is in continued operation for several generations. And we might with the more confidence anticipate such a result, when we see that a marked difference in complexion often exists between parent and offspring, or between the children of the same parents. Thus, it is a matter of familiar observation, that of two members of the same family, the one shall be a blonde, the other a brunette. Further, it is not uncommon to find, in individuals of the fair races, large patches of the surface almost as deeply coloured as the skin of the negro. On the other hand, albinoism, that is, the total absence of colouring matter in the skin, is probably as common among dark races as among fair. And Dr. Prichard has collected evidence which shows that in many of the individuals who have been designated as \u201c white Negroes,\u201d there has not been mere albinoism (that is, an entire absence of colouring matter), but a positive development of the colouring matter that characterises the xanthous variety, in which the complexion is fair and ruddy. Such being the tendency to variation presented by this character, we might fairly anticipate that it might undergo marked changes in the course of a long succession of generations, especially where the external conditions have been altered ; and there is no deficiency of valid historical evidence, that proves this to have been the case.\u2014Perhaps the most striking example that could be cited, is that afforded by the Jewish race ; in which there is no question that a general purity of descent has been preserved through a long succession of g\u00e9n\u00e9rions, during which the scattered residence of the race has subjected it to a great variety of climatic influences. Now, although the descendants of Abraham are still generally recognizable by certain peculiarities of physiognomy (so that they have often been quoted as examples of the permanence and fixity of the characters of races), yet a great variety of complexion exists among them. Thus, among the Jews whose families have been long settled in this country, although a light brunette hue with black hair is most common, yet a fair complexion, with blue eyes, is not unfrequent. In Germany and Poland, the ordinary complexion is more florid, and blue eyes are more common. On the other hand, the Jews of Portugal are almost invariably much darker than those of Northern and Central Europe, as are also those who still cling to their ancient home in Palestine. Lastly, the Jews that have been settled in India for a long succession of generations, have become nearly as black as the natives around them, so that the people of a particular colony at Mattacheri, in Cochin, in whom this change has not yet taken place, are distinguished by the appellation of\u201c white Jews.\u201d Hence it may be stated as a general proposition, that the complexion of the Jewish race tends to assimilate itself to that prevailing in any country in which their residence has been sufficiently\nprolonged ; and even admitting that a limited admixture with the surrounding population has taken place in any or all of these instances, still the introduction of a small quantity of extraneous blood does not by any means afford an adequate explanation of the change, since it has not been sufficient to alter any of the other characters of the race, and (as already remarked) the immediate results of such an occasional admixture are soon merged in the general uniformity of the mass. It is probable that, in races as in individuals, the influence of a tropical climate in darkening the complexion will be more decided, in proportion to the previous condition of the chro-matogenous function ; for example, that the Jews, whose natural complexion is swarthy, are more readily blackened than Saxons or Celts would be, the pigmentary matter in their epidermis being of a different character.\nThere are several other cases of the same kind, in which the historical testimony is less complete, but in which the deficiency is made up by philological evidence. Thus, the Ba-r\u00e2bra or Berberines of the higher parts of the Nile, appear, from the most careful researches that have been made into their history, to be the descendants of the Nobatae, who were brought by Diocletian from an oasis in the western country, fifteen centuries ago, to inhabit the valley of the Nile. The particular district out of which they issued was probably Kordofan, the inhabitants of which, true Negroes, still preserve and speak the Bar\u00e2bra language. In their habits of life, they show a considerable advance in civilisation ; and this has been accompanied by a considerable change in complexion, their present physiognomy and hue of skin presenting a marked resemblance to that of the ancient Egyptians. This alteration cannot be set down to any intermixture with the Arabs, or other inhabitants of the Nile Valley, from whom the Berberines keep themselves distinct.\u2014In like manner, the Funge, who made themselves masters of Sennaar about three centuries ago, although originally Negroes of the Shilukh nation, no longer present the physiognomy or complexion of that race, but much more nearly approach the Berberines. There appears, in both cases, to be a special tendency towards a red complexion, and even red hair ; and among the Funge, the individuals thus distinguished are stated to form a separate caste, being known under the name of \u201c El Akmar,\u201d or \u201c the red people.\u201d In Northern India, again, there is no doubt that many of the tribes of mountaineers, already alluded to as distinguished by fair complexion and blue eyes, are of the same stock with the inhabitants of the low country ; their language, traditions, religious observances, &c., being essentially the same. One of the most remarkable of these tribes is the Siah-P\u00f4sh, a people of exquisite beauty, with regular Grecian features, blue eyes, arched eyebrows, and a fair complexion, having no resemblance to the Affghan or Cashmerian people, near whom they dwell; their language principally","page":1336},{"file":"p1337.txt","language":"en","ocr_en":"1337\nvarieties of mankind.\nconsists of Sanscrit words, although Sanscrit is no longer the spoken language of any part of India ; and they are acquainted with only the simplest form of Hindoo mythology ; whence it may be fairly concluded, that they separated from the common stock at a very early period.\nThus, then, we have very strong evidence that a certain relation exists between climate and colour; and it is no valid objection to the existence of such a relation, to say that it is not perfectly uniform. For it is at least as uniform as the relation between colour and race, even where the climatic influences are the same ; that is, the difference of shade among people of different races that have been exposed sufficiently long to the same climatic influences, is not greater than that which presents itself among individuals of the very same nation. It would seem that, among the most dark-skinned races, there is a greater variety of complexion than is found in those of fairer hue. Such has been already shown to be the case among the Polynesian islanders ; and the following extract from Bishop He-ber\u2019s Journal will serve to indicate the amount of variety existing among the Hindoos. *' On first landing,\u201d he remarks, \u201c the great difference in colour between different natives struck me much. Of the crowd by whom we were surrounded, some were as black as Negroes, others merely copper-coloured, and others little darker than the Tunisines whom I have seen in Liverpool. Mr. Mill, the principal of the British College, who came down to meet me, and who has seen more of India than most men, tells me that he cannot account for this difference, which is general throughout the country, and every where striking. It is not merely the difference of exposure, since this variety is visible in the fishermen, who are naked all alike. Nor does it depend on caste, since very high-caste Brahmins are sometimes black, while Pariahs are comparatively fair. It seems, therefore, to be an accidental difference, like that of light and dark complexions in Europe ; though, where so much of the body is exposed to light, it becomes more striking here than in our own country.\u201d So among the inhabitants of Central Europe, it appears that a considerable modification in complexion has occurred, which is not sufficiently accounted for by the climatic change that has taken place in it since the classical epoch. For the Germanic nations were unanimously described by ancient authors as exceedingly fair, possessing yellow or red hair, and blue or grey eyes ; but these characters are now far from being prevalent among them, and it is only amongst the Scandinavian races that they are common to the mass of the people.\nOn the whole, then, it must be concluded that the Colour of the Skin is a character of such variable nature, that no positive line of demarcation can be drawn by its aid between the different races of mankind ; and whilst it must be freely admitted that we are far from comprehending all the influences which ope-\nrate to modify it, there seems ample evidence that climatic variations, whose agency is exerted for a sufficiently long period, are among the most efficient. This statement is obviously not invalidated by the fact, that Negroes and other dark-skinned people, who have lived for some time in temperate climates, have not lost their characteristic hue. For there is no example on record, so far as the author is aware, in which a Negro tribe or set of families has maintained itself for even three or four generations in a temperate climate, without intermixture either with the surrounding \u201c whites \u201d or with \u201c blacks \u201d of more immediate tropical descent. And until it shall have been shown that a continuous descent of many generations has taken place, in a group of Negroes completely isolated from the parent stock, and exposed to the conditions which are presumed to favour the production of the xanthous variety, without any considerable departure from their present complexion, there will be no negative evidence at all equivalent in probative value to the facts already cited on the affirmative side of the question.\n5. We have now to inquire into the characters furnished by the colour, texture, and mode of growth of the Hair, which have been much relied on by some writers, as more permanent and distinctive than those furnished by the hue of the skin. Thus, the Negro is usually characterised by his \u201c woolly \u201d hair ; while .he Mongolian races are affirmed to be peculiar in the scantiness of their pilous covering ; and the Hottentots are further separated by its tufted arrangement, which has been compared to the mode in which the bristles are set in\"a scrubbing-brush.\u2014Now in regard to the colour of the hair, it is scarcely necessary to remark that it cannot be taken alone as a distinctive character of races ; since it is liable to present the most extreme variations within the limits of any one. Among the xanthous Anglo-Saxons, for example, jet-black hair is by no means uncommon ; although various shades of brown are most frequently met with. Among Negroes, on the other hand, it is not at all rare to meet with a more or less complete departure from what may be freely admitted to be the prevalent character of their race. In the instances which have been already cited as proving the want of constancy in the complexion of the dark or melanic races, a corresponding change manifests itself in the colour of the hair, which often becomes of a reddish brown, or even of a much lighter hue. These may occur in individuals, or in whole tribes. Thus, Dr. Pickering speaks of having seen two children, in whom \u201cthe Negro aspect had so entirely disappeared, that they might have passed for the children of Europeans, but for the remarkable appearance of the hair,\u201d which he could \u201c compare to nothing but a white fleece.\u201d * The Cinghalese, according to the testimony of Dr. Davy, present as many va-\n* The Eaces of Man (Bohn\u2019s edition), p. 188","page":1337},{"file":"p1338.txt","language":"en","ocr_en":"1338\nVARIETIES OF MANKIND.\nrieties of hair as they do of complexion ; its hue ranging through black and brown to red and even flaxen : and precisely the same is true of the Tahitians and Marquesans among the Oceanic race, as well as among many other nations. The texture and mode of growth of the hair, however, are characters on which it would appear, at first sight, that more reliance may be placed. The pilous covering may be described as \u201c woolly,\u201d \u201c crisped\u201d or \u201cfrizzled,\u201d \u201c flowing \u201d or \u201c wavy,\u201d and \u201c straight.\u201d The African and Oceanic Negroes alone are characterised by \u201c woolly\u201d hair ; the Australians, Abyssinians, and many African nations, usually have the hair more or less \u201c crisped\u201d or \u201c frizzled ; \u201d among the Indo-Europeans, the \u201c flowing\u201d or \u201c wavy\u201d character prevails ; while a peculiar straightness most commonly presents itself among nations of Mongolian descent. It is obvious, however, that these several terms express little more than differences in degree. For if \u201c straight\u201d hair has a slight tendency to curl, it becomes \u201c wavy;\u201d if this tendency be increased, it is commonly termed \u201c curly ; \u201d the \u201c crisped \u201d or \u201c frizzled\u201d hair is little else than hair with a peculiarly stiff and close curl ; and the \u201c woolly \u201d covering of the head of the Negro is by no means so different from the crisped hair of other dark races, as the designation given to it would imply, the chief difference consisting in its closeness of texture and its tendency to mat together. As Dr. Prichard has correctly stated, it is clearly shown by microscopic observation that the hair of the Negro is not really \u201c wool,\u201d and it presents no constant structural difference from the jet-black hair which is not uncommon among Europeans. It has lately been asserted, however, by Dr. P. A. Browne, of Philadelphia, that the following definite structural differences do exist : \u2014\u201c The hair of the white man presents an oval section; that of the Choctaw and some other American Indians is cylindrical ; that of the Negro is eccentrically elliptical or flat. The hair of the white man, besides its cortex and intermediate fibres, has a central canal, which contains the colouring matter, when present. The wool of the Negro has no central canal, and the colouring matter is diffused, when present, either throughout the cortex, or this and the intermediate fibres. In hair the enveloping scales are comparatively few, smooth of surface, rounded at their points, and closely embrace the shaft ; in wool they are numerous, rough, sharp-pointed, and project from the shaft. Hence the hair of the white man will not felt ; the wool of the Negro will.\u201d* Now, upon this it may be remarked that neither of the characters specified by Dr. Browne will stand the test of extensive observation. The form of the shaft, as shown in transverse section, varies greatly in the hairs of the same race, and even in those of the same individual ; for not only is it sometimes round, sometimes oval, and (though more rarely) eccentrically elliptic or\n* Transactions of the American Medical Association, vol. iii. p. 62.\nnearly flat ; but it may be even reniform, or channelled on one side, a variety of which Dr. Browne takes no notice, except as occurring in the Hottentot. The central canal of the hair, which is occupied by medullary cells, is an extremely variable character ; being often undistinguishable in the hair of the white races. Moreover, the pigmentary' matter is sometimes almost exclusively confined to the cells of the central canal ; sometimes it is equally diffused through the whole fibrous substance forming the shaft of the hair : and sometimes we have even seen it in greatest abundance towards the periphery, the centre being pale. Hence the elliptical section, the absence of \u201c central canal,\u201d and the diffusion of pigmentary matter through the hair, are not in the least degree peculiar to the Negro, and cannot be regarded as characteristic of his hair. So, again, the writer takes upon himself to assert that there is not a greater difference in the degree of serration on the surface (which is due to the imbricated arrangement of the scales forming the cortical layer) between the hair of the Negro and that of other races, than exists among the individuals of any one race ; and that the Negro\u2019s hair does not approximate more closely to wool in this respect, than the Negro\u2019s cranium does to that of the chimpanzee. The only constant peculiarity of the Negro\u2019s hair is the tendency to a close curl ; and this seems connected with its form. As a general rule it may be stated that the roundest hairs curl least, and that those which show most flattening are the most disposed to curvature in their growth. But that there is something also in the nutrition of the hair which influences its mode of growth, appears from the following fact stated by Mr. Erasmus Wilson as the result of extensive observations : \u2014\u25a0 \u201c I have collected several instances in which the hair, naturally possessing a strong curl, becomes lank and straight if its possessor be out of health ; the straightness of the hair becoming as certain an index of a disordered state of the economy, as a yellow eye-ball or a white tongue.\u201d*\nNow if we attempt to apply the texture of the hair to the discrimination of races, we find that although it has a certain value as affording a character of general applicability, yet that this will not bear being carried too minutely into particulars. Thus, among the African nations, there are many whose affinity to the Negro race cannot be questioned, and which yet have merely \u201ccrisped\u201d or \u201cfrizzled\u201d hair, instead of a woolly covering ; and there are others which cannot be shown on any other grounds to have a different descent, among whom the hair is long and flowing. On the other hand, we not unfrequently meet with individuals among the Anglo-Saxon race, in whom the hair is not merely curly, but \u201c frizzled,\u201d and almost \u201c woolly\u201d in its texture. Among the Oceanic races, again, there is every gradation of the same kind ;\n* On the Management of the Skin, 3d ed. p. 77.","page":1338},{"file":"p1339.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\t1339\nand great varieties present themselves within the limits of any one tribe. Here, too, the influence of external conditions shows itself in a very marked degree ; for it is among the inhabitants of the lower levels bordering on the sea, between the tropics, who are most exposed to the vertical rays of the sun, their climatic conditions being nearly allied to those of the Negro, that the \u201cwoolly\u201d character most remarkably shows itself ; whilst in other tribes of the same race, which are not less prognathous, but live in higher and drier situations, the hair is only \u201c frizzled,\u201d or even becomes long and wavy. Even if, as Dr. Prichard justly remarks, the hair of the Negro were really analogous to wool, it would by no means prove the Negro to be a peculiar and separate stock, unless the peculiarity were constantly presented by all the nations of similar descent ; and were restricted to them alone ; for, as already pointed out, there are breeds of domesticated animals which bear wool, whilst others of the same species, under different climatic influences, are covered with long straight hair. It is not unimportant to notice, that wool is occasionally borne by the clog, ox, and hog, to neither of which it is natural ; whilst the sheep, whose ordinary covering is composed of it, occasionally exchange it for long straight hair. These facts so unequivocally prove that the texture of the hair is peculiarly liable to be influenced by external conditions, that it could only be on the strictest proof of invariability, that such a character could be properly adopted as a basis for specific distinction.\nAs examples in which there is historical evidence of alteration in the texture and mode of growth of the hair, it will be sufficient to refer to the case of the Bar\u00e2bras already cited, whose hair, originally woolly, has become longer and straighter, only retaining a slight crispness ; and to that of the Western Turks, whose chins are furnished with flowing beards, in which their Eastern relatives are almost entirely deficient.\nThe greatest peculiarity in the growth of the hair is exhibited by the Hottentot race. The following account of its appearance in a young Bushman, who recently died in the United States, is given by Dr. Parsons* : \u2014 \u201c His hair lay in little distinct, compact, curly tufts, twisted spirally ; and in the intervals of these tufts, the skin was distinctly seen. The filaments were very fine, some of them five inches long, and black. They contained a distinct cortex and granular medulla. The transverse section of a filament resembled that of the Negro\u2019s, except in being concave on one of the two longer sides of the ellipse,\u201d or reni-form. Thus, in the texture of the hair itself, the Hottentot seems allied to the Negro, whilst its sparseness reminds us of the scantiness by which the Mongolian races are generally characterised. We shall hereafter see, that there is strong reason for regarding the Hottentot race as of kin to the Negro ; and\n* Transactions of the American Medical Association, vol. iii, p 62.\nfor attributing the modification which it has undergone to the external conditions of its existence. The peculiar character of the chevelure of the Papuans, which will be noticed in the account of that race, seems to be chiefly due to its artificial treatment.\nFrom the Anatomical portion of our inquiry, then, we are led to the general conclusion, first, that no such difference exists in the external conformation or internal structure of the different Races of Men, as would justify the assertion of their distinct origin ; and, secondly, that although the comparison of the structural characters of races does not furnish any positive evidence of their descent from a common stock, it proves that even if their stocks were originally distinct, there could have been no essential difference between them, the descendants of any one such stock being able to assume the characters of another.\nOf the next subject for investigation, the Physiological conformity or diversity of the several races of mankind, a much briefer summary will be sufficient. This part of the inquiry has been pursued with great diligence and success by Dr. Prichard*, who lays it down as a general axiom (the truth of which must be admitted by all who are competent to form an opinion on the subject, its validity being confirmed by the careful study of those races of domesticated animals which are remarkable for the greatest amount of anatomical variation), that the great laws of the vital functions, such as those expressing the periods and duration of life, the economy of the sexes, and the phenomena of parturition and reproduction, are, with slight deviations resulting from external agencies, constant and uniform in each particular species; whilst there are usually decided differences in regard to the same peculiarities among races of animals, which, though nearly resembling each other, are yet specifically distinct.\nNow, taking the average duration of life as the first point of comparison, it has been shown by Dr. Prichard, that, whilst there is a marked difference in this respect between man and the highest apes\u2014-the full term of existence of the chimpanzee being stated by M. Lesson .at not more than thirty years, and that of inferior species being less, \u2014 there is absolutely no difference among the several races of mankind, the extreme age of the Negro and American races being at least as great as that of the European, with the same average duration of life under the same circumstances as regards climate, mode of life, &c.\nThe age at which the body attains its full development, also, appears to be the same amongst different races ; or, at any rate, does not differ more than among the different individuals of the same race. The inquiry into the epoch of the first menstruation has been most industriously prosecuted by Mr. Ro-\n*\nPhysical History of Mankind, vol. i.","page":1339},{"file":"p1340.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\nberton ; and its results, published from time to time, as they were obtained, have been lately collected in a form which admits of easy comparison.* It appears, from the evidence which he has brought together, that there is no considerable difference either in the average period of puberty, or in the earliest date of menstruation, among the greater number of tribes who are scattered over the whole of the habitable globe, from the equatorial to the polar regions , and that neither has a cold climate that influence in retarding it, nor a warm one in accelerating it, which is popularly attributed to these agencies respectively. The only well-marked exception to this general rule, occurs in the case of the Hindoo females, among whom the first menstruation occurs on the average about two years earlier than in this country. But this only arises from the fact, that a larger proportion of first menstruations among Hindoo females, takes place in the earlier years of that period, over which the commencement of puberty is distributed in European females, the distribution in the latter being more equable, as will be seen by the following table, furnished by Mr. Rober-ton : \u2014\nAges.\tHindustan.\tEngland.\n8\t3\t\t\n9\t8\t14\n10\t18\t55\n11\t80\t77\n12\t145\t142\n13\t139\t263\n14\t105\t396\n15\t45\t417\n16\t24\t340\n17\t18\t215\n18\t5\t138\n19\t3\t65\n20\t1\t33\n21\t2\t9\n22\t\u2014\t4\n23\t1\t1\n\t597\t2169\nFor whilst the average age of puberty in the Hindoo female is thirteen years, and in the British, fourteen years eleven months, the per-centage of menstruations under eleven years is nearly the same in the two countries, so that the current idea of the very early puberty of Hindoo females is quite incorrect ; and the difference in the average solely arises from the fact, that the greatest number of first menstruations occur among Hindoo females in the twelfth, thirteenth, and fourteenth years, whilst among the females of this country the larger proportion presents itself in the fourteenth, fifteenth, and sixteenth years. Now this difference, as Mr. Roberton justly remarks, cannot be attributed to climate, for Demerara and the West Indian Islands have a higher mean annual temperature than Cal-\n* Essays and Notes on the Physiology and Diseases of Women, and on Practical Midwifery. 8vo. London, 1851.\ncutta and the Dekhan ; and yet we know that the Negresses in these colonies are not earlier than the peasant women in England. A more robable cause, however, lies in the peculiar abits of the natives of that country, which tend, in more ways than one, to force forward the period of puberty. \u201c It is the law of the Shastras, that females shall be given in marriage before the occurrence of menstruation, and that, should consummation not take place until after this event, the marriage is a sin. Accordingly, it is the custom in Lower Bengal to send'the girl at the age of nine years to the house of her husband, unless the latter be so distant that it cannot be done ; and two ancient Hindoo sages are of opinion, that if the marriage is not consummated before the first appearance of the catamenia, the girl becomes \u2018degraded in rank.\u2019 At Bangalore it would seem that this revolting custom does not obtain, the husband refraining from taking his wife to his own house till not less than sixteen days have elapsed subsequently to puberty.\u201d* Now, it can scarcely be questioned that such a premature sexual excitement will have a tendency to accelerate the epoch of puberty; and that, when this is constantly acting through a long succession of generations, an early puberty may come to be a character of race. But besides this modus operandi of the custom in question, the following has been pointed out by Mr. Roberton :\u2014\u201cWhen it is recollected that the consummation of marriage among the Hindoos has taken place, at the latest, on the arrival of puberty, during a lapse of more than three thousand years, and that the practice is sanctioned by ancient laws and consecrated by custom, it is easy to conceive that those females who were latest in reaching puberty, would be the least sought after for wives,\u2014that such women would not be unlikely, in many instances, to remain unmarried,\u2014and that thus (owing to the origination of a preference on this ground in the selection of their wives, operating through a long period of time) Hindoo women would gradually come to consist, in a proportion different from that in Europe or elsewhere, of such as by constitution are early nubile. To me there seems nothing extravagant or far-fetched in this supposition. The production of a like state of things in England, in any particular district, is quite conceivable. Nothing is better established, than that early (or late) puberty is a family peculiarity. Let us, then, only suppose families, possessing this kind of constitution, to intermarry, and the peculiarity in question would be propagated, extended, and transmitted ; and so a race, distinguished by it, would be produced.\u201d-}- It is a justification of this view, that the mean age of puberty should differ in Bengal and the Dekhan, to the extent of nearly a year, being twelve years six months in the former province, and thirteen years five months in the latter, notwithstanding its warmer latitude ; for, as just stated,\n* Op. cit. p. 131.\tt Op. cit. p. 129.","page":1340},{"file":"p1341.txt","language":"en","ocr_en":"1341\nVARIETIES OF MANKIND.\nalthough formal marriages take place at a very early age throughout India, the custom is so far modified in the Dekhan, that consummation is not effected until after the first menstruation has appeared.\nThe frequency of the catamenial flux, and the epoch of life to which it extends, appear from Mr. Roberton\u2019s inquiries, to be no less constant among different races. It is quite true that the period of child-bearing is sooner terminated among the women of many tribes, especially in tropical climates, than it usually is in this country ; but this is fairly attributable to the earlier marriages, and the consequently premature excitement of the generative power, of which its earlier decline is the natural consequence. The same is continually seen in this country. The marked difference in this respect, that arises out of laws and customs affecting the marriage state, is shown by the fact, that in India the mean age for a first parturition is 15\u00a3 years, whilst among 500 Manchester female operatives, tabulated by Mr. Roberton, the mean age was found to be 23 years. Some very curious evidence has been collected by that gentleman, which goes to prove that marriages nearly as premature as those of Hindoo females were formerly sanctioned by law and public opinion in this country; and that in Ireland they have been by no means unfrequent within a recent period.\nThe duration of pregnancy is well known to be the same throughout all the races of mankind ; and this is a fact of peculiar importance, as a difference in this respect is elsewhere observable between species that are in other respects closely allied.\nThe fertility of hybrid races, originating in the intermixture of two races whose affinity is most remote, is a fact of which there can be no doubt whatever ; and there is strong reason to believe that those hybrid races, the parents of which are Europeans on one side, and the aborigines of any country on the other, are generally destined to become the dominant population of those countries. For, on the one hand, these \u201c half-castes \u201d very commonly combine the best attributes of the two races from whose admixture they sprang ; namely, the intelligence and mental activity of the European, and the climatic adaptation of the native.* And they are also in general distinguished for their fertility, when paired with each other, so that they are rapidly rising into numerical importance. On the other hand, this very intermixture, taking place as it usually does between an European father and a native mother, tends to diminish the number of the native population in a very remarkable manner ; for there is now a large amount of evidence, that when a native female of the American or Polynesian races has once been impregnated by an European male, she thenceforth loses ail power of conception from intercourse with\n* This is well seen in the case of the descendants of the mutineers of the Bounty and of Tahitian women, who now occupy Pitcairn\u2019s Island.\nthe male of her own race. This was first pointedly stated by that very intelligent traveller, the Count de Strzelecki, who has lived much among different races of aborigines, the natives of Canada, of the United States, of California, Mexico, the South American Republics, the Marquesas, Sandwich, and Society Islands, New Zealand, and Australia, and who affirms that in hundreds oj cases of this kind into which he has inquired, and of which he preserves memoranda, there has not been a single exception.*\nAs regards Australia and New Zealand, this statement, strange as it seems at first sight, has been fully borne out by independent evidence ; and it offers the most complete explanation yet given, of the very rapid decrease in the native population of the various islands of Oceania, in which European races have been long established. Nothing precisely analogous is known in any other case. Instances of the influence of the father of a first offspring upon subsequent offspring by another father, are so frequent, as to have given rise to a current belief among the breeders of domesticated animals, that such is the fact ; and the very ingenious hypothesis has been suggested by Mr. M\u2018Gillivray, and ably advocated by Dr. Harvey, that the female parent in such a case becomes inoculated with the qualities of the male, through the blood of the foetus, which partakes of the latter. But there is no known case, in which impregnation of a female by a male of a different species or variety has rendered her subsequently infertile to males of her own ; on the contrary, the facts just referred to, as to the extension of the influence of the first father over the subsequent progeny, indicate that such is not the case. Hence this peculiarity affords no ground whatever for the establishment of a specific distinction between the two races ; and the invalidity of such a distinction is at once indicated by the fact, that the peculiarity in question does not hold good in regard to the African races, the fertility of the Negro female with the male of her own race not being apparently impaired by 'previ\u00b0us fruitful intercourse with the European male, a kind of intercourse which is notoriously common in the West India Islands, and in the slave-holding states of North and South America, j'\n* See the Count de Strzelecki\u2019s Physical Description of New South Wales and Van Dieman\u2019s Land, pp. 345\u2014347. ; and Dr. Harvey\u2019s Papers on the Inoculation of the Maternal System with the Peculiarities _ of the Paternal, through the Foetus in Utero, in the Edinb. Monthly Journal for October, 1849, and October and November, 1850.\n_ t It ma7 be> as suggested by Dr. Harvey (loc. cit.), that the final purpose of this curious provision should be to replace the least improvable races by a population of a much higher order ; the aboriginals thus becoming extinct without violence, but in the natural course of things ; and their places being occupied either by half-breeds or Europeans. And, on the other hand, the immunity of the Negro may be designed to preserve his tenure of those parts of the earth, whether in subserviency to the European or independently of him, where, by reason of the","page":1341},{"file":"p1342.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\nThe Psychical comparison of the various races of mankind is really, in a practical point of view, the most important department of the whole investigation ; and yet it has been the most neglected, until Dr. Prichard took up the inquiry. Whilst the capaciousness of the skulls of the Negro and European has been measured and compared, but little account has been taken of the workings of the brains which they contained. The colour of the skin, the flatness or projection of the nose, the lankness or crispness of the hair, the straightness or curvature of the limbs, have been scrutinised and contrasted, as if these alone constituted the proper description of Man ; though it is surely in his mental character and its manifestations, that the attributes of humanity peculiarly consist.\nThe tests by which we recognise the claims of the outcast and degraded of our own country to a common humanity, are surely the same as those by which we should estimate the true relation of the Negro, the Bushman, or the Australian, to the cultivated European. We must not judge of their capabilities solely by their manner of life, however wretched that may be ; since this is often, in great degree, forced upon them by external circumstances. Nor have we any right to pronounce them incapable of entertaining any particular class of ideas, simply because we cannot find the traces of these in their existing forms of expression. It is only when such people have been attentively studied \u2014not by passing travellers, who, though they may pick up a little of their language, see little of their inner life,\u2014but by residents who have succeeded in gaining acquaintance with habits which a jealous reserve would conceal, and ideas which the imperfections . of language render most difficult of transmission*, that we have any right to affirm what they are ; and even this amount of information affords little means of judging what they may become.\nIt will be only when the effect of education, intellectual, moral, and religious, has been fairly tested, that we shall be entitled to speak of any essential and constant psychical difference between ourselves and the most degraded beings clothed in a human form. It will only be when the influence of a perfect equality in civilisation and social position has been ineffectually brought to bear upon them for several consecutive generations, that we shall be entitled to say, of the Negro or of any other race, that it is separated by an \u201c impassable barrier \u201d from those which arrogate to themselves an inalienable superiority in intellectual and moral endowments. All our present knowledge on this subject tends to show that\nhigh temperature, the European cannot toil in the way or to the degree which the cultivation of those regions requires.\n* A curious example of the difficulty of fully comprehending the import of abstract terms, in a language which has been so much studied, both by linguists and by philologists, as the Chinese, will be found in the Athen\u00e6um for March 1. 1851.\nno such barrier exists, and that there is a real community of psychical characters among the different races of men ; the differences in the degree of their positive and relative development, not being greater than those which exist in the successive or contemporaneous varieties of our own race. And it may be added, too, that in almost every instance, the more we learn concerning any particular nation or tribe reputed to possess the meanest possible aspect of humanity, the more we generally have to recede from the harshness of our first impressions.\nA very striking example of the near affinity that may exist between the most degraded \u201c outcasts of humanity,\u201d and races considerably advanced in civilisation and intelligence, is presented by the relationship of the Bushmen of the Cape of Good Hope to the Hottentot population which tenanted that region previously to the arrival of European colonists. The following is a graphic account recently given of them by one who has had ample opportunities of observation :\u2014\u201c The Dutch Boer, the Griqua, the Bechuana, the Kaffir, all entertain the same dread of, and aversion to, these dwarfish hordes, who, armed with their diminutive bows and poisoned arrows, recklessly plunder and devastate, without regard either to nation or colour, and are in their turn hunted down and destroyed like beasts of prey, which in many respects they so nearly resemble. .\t.\t. Time, a knowledge\nof, and an occasional intercourse with, people more civilised than themselves, have -made little change in the habits and disposition of this extraordinary race. The Bushman still continues unrelentingly to plunder, and cruelly to destroy, whenever the opportunity presents itself. His residence is still amongst inaccessible hills, in the rude cave or cleft of the rock\u2014 on the level karroo, in the shallow burrow, scooped out with a stick, and sheltered with a frail mat. He still, with deadly effect, draws his diminutive bow, and shoots his poisoned arrows against man and beast. Disdaining labour of any kind, he seizes when he can on the farmers\u2019 herds and flocks, recklessly destroys what he cannot devour, wallows for consecutive days with vultures and jackals amidst the carcases of the slain, and, when fully gorged to the throat, slumbers in lethargic stupor like a wild beast, till, aroused by hunger, he is compelled to wander forth again in quest of prey. When he cannot plunder cattle, he eagerly pursues the denizens of the waste, feasts indifferently on the lion or the hedgehog, and, failing such dainty morsels, philosophically contents himself with roots, bulbs, locusts, ants, pieces of hide steeped in water, or, as a last resource, he tightens his \u2018girdle of famine,\u2019 and, as Pringle says,\u2014\n\u2018 He lays bim down, to sleep away,\nIn languid trance, tbe weary day.\u2019\nWhether this precarious mode of existence may, or may not, have influenced the personal appearance and stature of the Bushmen it is","page":1342},{"file":"p1343.txt","language":"en","ocr_en":"134-3\nVARIETIES OF MANKIND.\ndifficult to say, but a more wretched-looking set of beings cannot easily be imagined. The average height of the men is considerably under five feet, that of the women little exceeding four. Their shameless state of nearly complete nudity, their brutalised habits of voracity, filth, and cruelty of disposition, appear to place them completely on a level with the brute creation, whilst the * clicking \u2019 tones of a language, composed of the most unpronounceable and, discordant noises, more resemble the jabbering of apes than sounds uttered by human beings.\u201d*\nNow, there is ample evidence that the Cape Bushmen are a degraded caste of the Hottentot race. They agree with the Hottentots in all the peculiarities of physiognomy, cranial conformation, &c., by which the latter are characterised; and a careful comparison of the languages of the two races has shown that there is an essential affinity between them. It has been ascertained by Dr. Andrew Smith, that many of the Bushman hordes vary their speech designedly, by affecting a singular mode of utterance (employing the peculiar clapping or clicking of the tongue, which is characteristic of the Hottentot language, so incessantly, that they seem to be giving utterance to a jargon consisting of an uninterrupted succession of claps), and even adopting new words, in order to make their meaning unintelligible to all but the members of their own community. According to the same authority, nearly all the South African tribes who have, made any advances in civilisation, are surrounded by more barbarous hordes, whose abodes are in the wilderness and in the fastnesses of mountains and forests, and who constantly recruit their numbers by such fugitives as crime and destitution may have driven from their own more honest and thriving communities. In this manner it has happened that within a comparatively recent period many tribes of Hottentots have been degraded into Bushmen, through the oppressions to which they have been subjected at the hands of their more civilised neighbours.\nNow, although of the Hottentots themselves we are accustomed to form a very low estimate, \u2014 our ideas of them having been chiefly derived from the intercourse of the Cape settlers with the tribes which have been their nearest neighbours, and which have unfortunately undergone that deterioration which is so often found to be the first result of the contact of civilised with comparatively savage nations,\u2014it appears from the accounts of them given by Dutch writers at the time of the first settlement of the Cape, that they were a people considerably advanced in civilisation, and possessed of many estimable qualities. Their besetting sins seem to be indolence and a love of drink (in this respect strongly resembling the Irish) ; yet when they can be induced to apply, they show no want of capacity or vigour. The testimony of\n* Lieut.-Colonel E. E. Napier\u2019s Excursions in Southern Africa.\nLieut.-Col. Napier is very strong as to their merits as soldiers when officered by Europeans ; \u201c and it has been,\u201d he says, \u201c on the Cape Mounted Rifles, composed chiefly of this race, that many of the greatest hardships, fatigues, and dangers of the last and former Kaffir wars have principally fallen.\u201d * It has been frequently said that the Hottentots differ from the higher races, in their incapacity to form or to receive religious ideas. This is, however, by no means true. The early Dutch settlers describe them as having a definite religion of their own ; and it was their obstinate adhesion to this, which was the real obstacle to the introduction of Christianity among them. When the attempt was per-severingly made and rightly directed, the Hottentot nation lent a more willing ear than any other race in a similar condition has done to the preaching of Christianity ; and no people has been more strikingly and speedily improved by its reception.\nNow, if we compare the condition of these people with that of the lowest members of the population of countries that claim to be most advanced in civilisation, we find that the difference is not so great as it might at first appear. Unfortunately, there is scarcely a civilised nation, in the very bosom of which there does not exist an outcast population, neither less reckless, nor less prone to the indulgence of their worst passions, than the miserable Bushmen, and only restrained from breaking loose by external coercion. The want of forethought and wild desire of revenge, which are said to be among the most striking characteristics of the Bushmen, are scarcely less characteristic of those classes dangereuses, which, as often as the arm of the law is paralysed, issue from the unknown deserts of our great towns, and rival in their excesses of wanton cruelty, the most terrible exhibitions of barbarian inhumanity. So, again, there is nothing in the inaptitude of any barbarous tribe for religious impressions, which surpasses that of the young heathens of our own land, who, when first induced to attend a \u201c ragged school,\u201d are recorded to have mingled \u201c Jim Crow \u201d with the strains of adoration in which they were invited to join, and to have done their best, by grimaces and gestures, to distract the attention of those who were fixing their thoughts on the solemn offering of prayer ; or of those who, after having joined with apparent sincerity in religious worship, simultaneously took their departure as the hour approached for the breaking up of the city congregations, in order that they might \u201c go to work,\u201d as they expressed it ; that is, that they might exert their thievish ingenuity upon the dispersing crowds. Now if, on the one hand, we admit the influence of want, ignorance, and neglect, in accounting for the debasement of the savages of ourown\n* The conduct of this corps in the recent outbreak (March 20. 1851), is stated by the Governor to have been most admirable. It was under its escort alone, that he forced his way through a country entirely in possession of the Kaffirs.","page":1343},{"file":"p1344.txt","language":"en","ocr_en":"1344\nVARIETIES OF MANKIND.\ngreat towns, and yet cherish the belief that, so far from being irreclaimable, they may at least be brought up to the standard from which they have degenerated ; on the other hand, we cannot well doubt the operation of the same causes on the outcasts of the Hottentot races, or refuse to believe that even the wretched Bushmen might be brought back at least to the original condition of the people from among whom they have been driven forth*\nIt may be freely admitted that the different races of mankind exhibit very different degrees of capacity for intellectual, moral, and social improvement ; but this difference is not greater than that which exists amongst individuals of the most favoured races, and cannot\n* This parallel, suggested by the writer of this article some time since (Edinburgh Review, Oct. 1848), has been recently followed up by the author of \u201c London Labour and the London Poor ; \u201d who has shown that a remarkable correspondence exists in mental habitudes and mode of life, between the sonquas or paupers of the Hottentot race, and the wandering outcasts of our own, who possess nothing but what they acquire by depredation from the industrious, provident, and civilised portion of the community. The latter, like the former, have a secret or \u201c slang \u201d language of their own, adapted for the concealment of their designs ; and, as already mentioned, they are generally characterised by the great development of the facial in proportion to that of the cranial part of the skull. The one tribe of \u201c nomads,\u201d like the other, \u201c is distinguished from civilised man, by his repugnance to regular and continuous labour ; by his want of providence in laying up a store for the future ; by his inability to perceive consequences ever so slightly removed from immediate apprehension; by his passion for stupifying herbs and roots, and, when possible, for intoxicating fermented liquors ; by his extraordinary powers of enduring pain ; by an immoderate love of gaming, frequently risking his own personal liberty upon a single cast; by his love of libidinous dances; by the pleasure he experiences in witnessing the suffering of sentient creatures; by his delight in warfare and all perilous sports ; by his desire for vengeance ; by the looseness of his notions as to property ; by the absence of chastity among his women, and his disregard of female honour ; and lastly, by his vague sense of religion, his rude idea of a Creator, and utter absence of all appreciation of the mercy of the Divine Spirit.\u201d It is further remarkable that the nomadic tribes seem to possess (sometimes hereditarily, sometimes as an acquired habit) such a constitutional adaptation to a wandering life, that, despite its privations, its dangers, and its hardships, they can rarely be induced to abandon it. It is well known that among the many instances in which the aborigines of Australia or of North America have been brought up and educated from an early age amongst Europeans, there are few, if any, in which they have been satisfied to to remain and to adopt the habits of civilised life. On approaching manhood, they become restless, and take the first opportunity of absconding to join their brethren in \u201c the bush.\u201d So, again, there are numerous examples of white men adopting, by their own choice, all the usages of the Indian hunter or Australian bushman ; and these, having once imbibed a fondness for the nomadic life, are as irreclaimable as those who have grown up in it. The same is the case, according to Mr. Mayhew, with a large proportion of the \u201c street-folk \u201d of London ; \u2022 who will give up situations affording comforts and advantages of a far superior order, to return to the indulgence of their wandering propensity.\nfor a moment be assumed as the basis for specific distinctions between them. If the Negro, for example, is at present far behind the European standard, yet, under favourable circumstances, the intellect and moral character of individual Negroes have been elevated to it ; while, on the other hand, we have too frequent proof that the intellect and moral character of the European are capable, not merely in individuals, but in families and groups of people, of sinking even below the average African standard. It is the observation of all who have had experience in the education of the children of races reputed to be inferior, such as Negroes, Hottentots, and Australians, that their capacity is at least equal to that of the lowest class of our own youthful town population, and that their docility is, if anything, greater. That this mental development is generally checked at an early age, and that the adults of these races too frequently remain through life in the condition of \u201c children of a larger growth,\u201d may be freely conceded. But observation of the difference in developmental power, between the mind of the descendant of an educated ancestry, and that of the descendant of an ignorant and uncultivated peasantry, shows that within the limits of the same race the same difference may exist ; and nothing is more likely to maintain it, than the absence of any encouragement to advancement, and the persistence, on the part of society at large, in the doctrine that the Negro never can be admitted within the pale of white civilisation.\nLooking to the fact already mentioned (p. 1 341.), as to the\u2019absence of that tendency to extinction in the African races, by sexual contamination from Europeans, which shows itself so remarkably among other aborigines, it is not a little interesting to observe, that there are elements in the Negro character, which have been deemed, by competent observers, capable of working a considerable improvement in even Anglo-Saxon civilisation. Many intelligent thinkers have come to the conclusion, that the boasted superiority of the latter is, after all, more intellectual than moral ; and that in purity and disinterestedness of the affections, in childlike simplicity and gentleness of demeanour, in fact, in all the milder graces of the Christian temper, we may have even much to learn of the despised Negro. \u201c I should expect,\u201d says Channing, \u201cfrom the African race, if. civilised, less energy, less courage, less Intellectual originality than in ours ; but more amiableness, tranquillity, gentleness, and content. They might not rise to an equality in outward condition, but would probably be a much happier race.\u201d And it is to be remembered that these and similar remarks have been made respecting the Negroes of the Guinea coast, or their descendants, who are, as we shall presently see, the most degraded of all the African races, except those of the neighbourhood of the Cape, whose degradation has been in great measure the result of European oppression, and the introduction of European vices. It","page":1344},{"file":"p1345.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\t1345\nis not a little remarkable that the earliest civilisation of which we have any distinct traces in the western portion of the Old World, \u2014 perhaps the very earliest development of the arts of life and of a spiritual philosophy that man has witnessed\u2014should have presented itself in a race which was not only African in its locality, but also in its affinities, such being demonstrably the character of the Ancient Egyptians, as will be seen hereafter. Yet to this race the civilisation of Greece, of Rome, and of Western Europe may be in great measure ascribed; and long after the time when its power and intelligence had gained their highest state of development, the progenitors of the Anglo-Saxon race, both in Britain and in Germany, were in a state of barbaric ignorance and brutalism.\nReferring, for the particulars of this part of the enquiry, to the valuable collection of information brought together by Dr. Prichard chiefly from the records of the Moravian missionaries who have planted themselves over almost every portion of the habitable globe, and who have gained a more intimate acquaintance with the mental habits and feelings of the people among whom they dwell, than has been acquired by any other class of European settlers; the following may be adopted as its general results : \u2014 In all the races of mankind, with which any adequate acquaintance has been gained, unequivocal indications may be discerned of the same moral and intellectual nature as that which the most civilised tribes exhibit ; and these indications become more obvious, the more complete is our knowledge of their habits, not merely of action, but of thought. We can trace, in short, among all the tribes who are endowed with the faculty of articulate speech, the same rational, human nature; superior to that of the highest brutes, not merely in the complexity of the processes which it is capable of performing, but in that capacity for generating abstract ideas, and thus arriving at general principles, which, so far as we have the means of judgment, appears to be the distinguishing attribute of man. So, again, we discover in all of them the same elements of moral feeling; the same sympathies and susceptibilities of affection ; the same conscience, or internal conviction of accountableness, more or less fully developed ; the same sentiments of guilt and self-condemnation, and the same desire for expiation. These principles take very different forms of expression, even in civilised life ; much more, therefore, ought we to be prepared for finding nothing more, even among the best specimens of uncivilised barbarism, than the mere rudiments of a higher understanding, and of a nobler moral nature, than that which they have at present reached. But the rudiments are there, though not always in the same degree of forwardness for being moulded to the institutions of a more regular society, for the development of the intellectual powers under a rational education, and for that growth of the moral and religious sentiments which Christianity is pre-eminently VOL. IV,\nfitted to promote in every mind that opens itself to its benign influence.\nThe general conclusion, then, which we seem entitled to draw from the Anatomical, Physiological, and Psychological facts to which reference has been made, is that all the human races may have had a common origin ; since they all possess the same constant characters, and differ only in those which can be shown to vary from generation to generation.\u2014We have now to inquire, lastly, into the bearing of philological evidence upon the same question ; and as this department of the inquiry is more foreign than the preceding to the character of the present work, a brief notice of its chief results is all that can be here admitted. These results, it may be remarked, are of extremely recent acquisition. In fact, there is no department of ethnology in which progress is at present so rapid, as it is in the study of glottology.\nNow it may be observed, in the first place, that what has been just said of the community of psychical nature amongst the several races of mankind, is very strongly confirmed by the general fact of the universality of spoken language, and of the power of translating from one language to another. Dogs and monkeys may have languages of their own ; but there is no such relation between these and ours, as may enable us to comprehend them ; and where brute animals have been taught to comprehend human language, it has been only so far as to acquire a mental association between the sounds of certain words, and the material objects which they represent. This is but the first and simplest stage of the acquirement of language, as every one must perceive, who watches the development of the power of communication by this means, in early childhood. A very large part of all languages, but especially of those employed by nations advanced in intellectual culture, consists of terms expressive of ideas and relations, rather than of material objects ; and it is in the capacity for expressing the former, that the distinctive attributes of human language appear specially to consist. This capacity, though existing more or less in all languages, will obviously vary considerably in degree, according to the intellectual culture of the people of whose thoughts they are the habitual expression ; and the power of fully rendering the thoughts conveyed by one language into another tongue, must of course depend in great part upon the relative advancement of the two. The abstractions of a German transcendental philosopher do not always admit of being effectively conveyed, even in a tongue so nearly related as the English to their original, far less could they be translated into Hottentot gibberish. So, again, the peculiar style of eloquence cultivated in the East, does not produce its adequate effect, when rendered in Western tongues. But any two barbarous languages, or any two which are highly cultivated, are, on the whole, so pervaded by a\n4 R","page":1345},{"file":"p1346.txt","language":"en","ocr_en":"1346\nVARIETIES OF MANKIND.\nsameness of character, as to bear witness to the similarity of their internal source.\nThe affinities between languages are sought by philologists in two entirely different directions ; namely, in their vocabularies, and in their methods of grammatical construction. In comparing the former, it is of course necessary to make due allowance for the possible influence of conquest, intermixture, or frequent intercourse, in modifying the original tongues ; but the experienced enquirer may generally eliminate this source of error, by placing his chief reliance on what are termed \u2022primary words, i. e. on words which serve to represent the universal ideas of a people in the most simple state of existence. Such are the terms expressive of family relations ; the names of the most striking objects of the visible universe, the sun, moon, stars, trees, rivers, &c. ; terms distinguishing the principal parts of the body, as the head, eyes, hands, and feet ; the numerals, up to five, ten, or twenty ; and verbs descriptive of the most common sensations and bodily acts, such as seeing, hearing, eating, drinking, sleeping. Such primary words are never wanting in the language of any nation ; and it has been ascertained by observation, that they are the last to undergo change, either in the spontaneous modifications which take place in the course of time, or under the disturbing influence of a foreign idiom ; so that a conformity in primary words affords very strong evidence of a community of origin among the nations which exhibit it.\u2014The evidence afforded by conformity in grammatical construction, requires a more intimate acquaintance than is needed for the preceding, with what is sometimes called the genius of the language ; but when it has been gained, it is frequently even more important than that furnished by the vocabularies. For there are many cases in which the latter are so continually undergoing important changes (the want of written records allowing them to possess no more than a traditional permanence), that the divergence of tongues becomes so great, in the course of even a few generations, as to prevent tribes descended from a common ancestry from understanding one another ; and yet the system of grammatical construction, which depends more upon the grade of mental development, and upon the habits of thought, exhibits a remarkable permanence.\nThe following are the principal types of construction, or \u201c methods by which the relation between the different words that constitute sentences is indicated,\u201d according to a very recent and distinguished authority.*\n1.\tThe Aptotic type, of which the Chinese is an example. In this, there is a total absence of inflections ; and the words which, in languages of the classical form, do the work of the inflections, that is, express the relations of the principal words to each other, are themselves most commonly the names of\n* Dr. R. G. Latham, on the Natural History of the Varieties of Man, p. 9.\nobjects and actions, i. e., nouns and verbs. \u201c Thus if,\u201d says Dr. Latham, \u201c instead of saying, I go to London, figs come from Turkey, the sun shines through the air, we said I go end London, figs come origin Turkey, the sun shines passage air, we should discourse after the manner of the Chinese.\u201d This is the lowest grade of linguistic development.\n2.\tThe Agglutinate type, which is carried to its fullest extent in the American languages. These possess inflexions, which can be generally shown to have arisen out of the juxta-position and composition of different words, the incorporation not having been sufficiently complete wholly to disguise the originally independent and separate character of the inflexional addition. This may be regarded as a decided advance in development.\n3.\tThe Amalgamate type, of which the classical languages are the most perfect examples. These possess a very complete system of inflexions, which express the relation between the fundamental idea denoted by the term, and some other ; and these inflexions are so completely incorporated with the root with which they are conjoined, that their existence as separate and independent words cannot be demonstrated, and can only be supported upon the analogy of the agglutinate languages. Thus, \u201c in a word like hominem, there are two parts, homin, radical ; em, inflexional. In the word te-tig-i, there are the same. The power of these parts is clear. The tig- and homin- denote the simple action or the simple object. The te- denotes the time in which it takes place ; the i, the agent. In the proposition te-tig-i liomin-em, the em denotes the relation between the object (the man touched) and the action (of touching). logically, there are two ideas, e. g. that of the action or object, and that of the super-added conditions in respect to time, agency, and relation.\u201d\n4.\tThe Anaptotic type, of which the English is an example. This designation is given to languages which were once inflexional, but which have in great part ceased to be so. In such we find that the auxiliary words which do the work of the Greek and Latin inflexions, are not names of objects and actions like those of the Chinese language, but possess (generally speaking) a purely abstract value, having a meaning only when in context with other words. Thus, where the Roman said te-tig-i, we say, I have touched ; where the Roman said patri, we say to father; where a Roman said tangam, we say, I will (or shall) touch. In many of these auxiliary words, however, an independent meaning can be clearly seen ; thus have and will are obviously verbs in their own right ; and the conjunction if is a corruption of the Saxon gif (give). Moreover, the inflexions are seldom or never wholly disused ; so that these anaptotic languages always preserve relations of affinity to those of the two preceding types, of which they may be considered a peculiar development.\nTo one or other of these types, or to tran-","page":1346},{"file":"p1347.txt","language":"en","ocr_en":"1347\nVARIETIES OF MANKIND.\nsitional grades between them, it is believed that all existing languages may be referred. It is remarkable that the development of a language should not by any means correspond to the advance of civilisation, so far, at least, as this is manifested by progress in the arts of life. The Chinese, for instance, of all known languages, most completely preserves, in a fixed or stereotyped condition, that earliest phase in the development of speech, in which every word corresponded to, or represented, a substantial object in the outward world ; and it cannot be denied that a considerable amount of intellectual development is to be found amidst that people. And from what is known of the ancient Egyptian language, this appears to have been nearly in the same condition. On the other hand, there are many languages of comparatively barbarous nations, even belonging to the same group with the Chinese, which possess much greater flexibility. The highest development of language however, is undoubtedly to be found coincident with the highest intellectual cultivation ; since this pre-eminently shows itself in the Indo-European tongues, of which the Sanscrit may be taken as the type, the Hellenic presenting its highest development in the amalgamate form, and the English in the anaptotic. In both these do we find that the general plan of construction tends to give to every single word a fixed and definite meaning, and at the same time, to render it subservient to the general idea that the sentence is to unfold, which is obviously the great end and aim of language ; whilst in the Chinese, every spoken word has an immense variety of meanings, and its import being determined, partly by its place in the sentence, partly by the tones or accents with which it is pronounced, and in the written language by an immense number of conventional signs derived from figurative sources, which are destined, not to express sounds, but to suggest ideas, and thus to assist the reader in guessing the meaning of the word.\nNow the most positive evidence which philology is able to afford, in regard to the affinities of two languages, is undoubtedly that which is derived from their conformity both in vocabulary and in grammar. But it frequently happens that one of these kinds of evidence is deficient ; and the degree of reliance that can be placed upon the other, taken alone, must depend greatly upon the circumstances of the individual case. Thus, if there be evidence that the vocabulary of one of these languages is in a state of continual change, an entire difference of vocabularies is no obstacle to the idea of the affinity between two languages, when this is decidedly indicated by a striking conformity in their systems of construction. On the other hand, when twTo languages or groups of languages differ greatly in their construction, but present a certain degree of verbal correspondence, full weight may be attached to that correspondence, if it can be proved that it has not been the result of intercourse subsequently to the\ndivergence of the stock, and if it can be shown to be probable that their separation took place at a period when as yet the grammatical development of both languages was in its infancy. The first appears to be true of the American languages, which seem, as a whole, to be legitimately referable to a common stock, notwithstanding their complete verbal diversity. The second is the aspect under which it appears likely that the Indo-European or Japetic, and the Syro-Arabian or Semitic groups of languages will come to present themselves ; the results of the recent labours of Rawlinson, Layard, Botta and others, on Eastern Arch\u00e6ology, tending decidedly in this direction.\nPhilological inquiry, then, must be looked to as the chief means of determining the question of radiation from a single centre or from multiple centres ; and although, in the present state of this department of science it would be unsafe to venture on a positive conclusion, yet the following may be considered as the principal groups under which the various languages hitherto studied may be arranged.\n1.\tThe Indo-European, sometimes termed Indo-German, frequently Japetic, and by late writers Arian, or Iranian. This group comprehends nearly all the existing languages of Europe, and those of a portion of South-Western Asia.\n2.\tThe Syro-Arabian, often termed Semitic; which are spoken by a large part of the population of Syria, Arabia, and Northern and Eastern Africa.\n3.\tThe Turanian, or Ugro-Tartarian; which are spoken by the (Mongolian) people of High Asia and of certain parts of Northern Europe.\n4.\tThe Seriform, or Indo-Chinese ; which are spoken by the people of South-Eastern Asia.\n5.\tThe African ; which are spoken by the people of Central and Southern Africa.\n6.\tThe Malayo-Polynesian ; which are spoken by the inhabitants of the numerous islands and island-continents of Oceania.\n7.\tThe American ; which are spoken by the inhabitants of the New World, from the Arctic Sea to Cape Horn.\nNow it is not a little curious that the linguistic affinity should often be strongest, where the conformity in physical characters is slightest, and weakest when this is strongest. Thus among the Malayo-Polynesian and the American races, as already remarked, there are very striking differences in conformation, features, complexion, &c. ; and yet the linguistic affinity of the great mass of tribes forming each group is not now doubted by any philologist, though a doubt may still hang over some particular cases. On the other hand, the hiatus between the Turanian and the Seriform languages is very wide ; but the physical conformity is so strong between the Chinese and the typical Mongolian nations, that no ethnologist has ever thought of as-\n4 r 2","page":1347},{"file":"p1348.txt","language":"en","ocr_en":"1348\nVARIETIES OF MANKIND.\nsigning to them a distinct origin. So, again, there would seem to be no near relationship between the American and the Turanian languages ; but the affinity of the two stocks appears to be established by the transition-link afforded by the Esquimaux, which are Mongolian in their conformation and American in their language. The affinity of the Semitic and Japetic languages, moreover, is so deeply hidden, as to have, until recently, almost defied discovery ; and yet the people who speak them so far resemble one another in physical characters, that they have been almost invariably associated together under the general designation of the Caucasian race. The common origin of the inhabitants of the continents of Europe, Asia, and America is thus pointedly indicated by the combination of these two sources of evidence. The portion of the Malayo-Polynesian race, that is, in nearest proximity with South-Eastern Asia, presents such a striking resemblance in physical characters to the inhabitants of the neighbouring part of that great continent, that their community of origin can scarcely be doubted ; and when certain points of resemblance between some of the Oceanic and Indian dialects are taken into account, this inference receives strong confirmation. The African nations have long been regarded as the most isolated from the common centre from which all the others appear to have radiated; but recent investigations have shown that such isolation has no real existence. For, on the one hand, there are tribes which form (like the Esquimaux) a connecting link between the Semitic and proper African families, being African in their conformation, but Semitic in their language ; and, on the other, the study which has been recently bestowed on the proper African languages, especially by Dr. Latham, has shown them to have so much in common with the Semitic tongues, that, with the additional evidence derivable from community of certain usages, extending through vast areas physically isolated from each other, it now seems impossible to believe but that the African nations are nearly related to the Semitic, and are through them, derivable from the great Asiatic centre.\nIV. General Survey of the principal Families of Mankind.\nIn the summary view which will now be presented, of the characters of the principal varieties of the human race, it will be convenient, in the first instance, to arrange them according to their existing geographical distribution, stating, under each head, the most important peculiarities in physical conformation, in psychical character, and in language, which they may respectively present. A general scheme of their probable relations of affinity will be subsequently given.\nI. European Nations. \u2014 The collective body of European nations, with the exception of the Lapps, present a great uniformity\nin physical characters ; for although minor differences exist among their subordinate groups, they all possess the elliptical cranium, the symmetrical form, the xanthous complexion, and the flowing hair, which characterise what is ordinarily designated as the Caucasian variety. This group of nations, however, must be primarily divided into those of Arlan or Indo-Median origin, and those whose origin is probably or certainly Mongolian. Under the latter head may be ranked (as already remarked) the Lapps and Finns of Scandinavia ; the Magyars of Hungary ; the Turks of Turkey ; not improbably the Basques or Euskaldunes of Biscay and Navarre; and (possibly) the Albanians or mountaineers of ancient Illyria and Epirus.* The European tribes of the Arian stock are considered by Dr. Latham as fundamentally divisible into the two great groups of Celts and Indo-Germans. The former seem to have detached themselves from the common stock, before the evolution of the language had proceeded to the formation of the cases of the nouns, but after that of the persons of the verbs had taken place f; and their language presents obvious traces of agglutination, which, as already shown, marks an early stage in linguistic developement. The eastern origin of the Celtic nations was first demonstrated by Dr. Prichard j, and has been subsequently more fully proved by Pictet.\u00a7 The typical Celts exhibit somewhat of that development of the malar bones, which is carried to its fullest extent in the pyramidal skull ; and in their comparatively unprogressive psychical character they contrast remarkably with the Germanic group of nations. The Indo-Germans, on the other hand, seem to have detached themselves from the common stock after the evolution of the cases of nouns had taken place ; and their language presents less evidence of agglutination than does the Celtic. The Eastern origin of this group of nations is not now doubted by any competent ethnologist ; for their languages, in spite of their diversity, constitute but one philological group, being united alike by community in many of the most important primary words, and by general similarity of grammatical construction ; and being obviously all formed upon the same base with the Sanscrit, if not upon that language itself. Of all extant European dialects, the Lettish and Lithuanian approach most nearly to the ancient Sanscrit ; but a still nearer approach seems to have been presented by the old Prussian, a dialect now extinct, which maintained, to the sixteenth century, a very slightly changed form of the Zend or Median language, which was an early derivation from the Sanscrit. Whilst every one of the Indo-Germanic languages bears traits of\n* See on this last point Dr. Latham\u2019s \u201c Natural History of the Varieties of Man,\u201d p. 552.\nt Op. cit. p. 529.\n+ On the Eastern Origin of the Celtic Nations, 1831.\n\u00a7 De l\u2019Affinit\u00e9' des Langues Celtiques avec le Sanscrit; Paris, 1837.","page":1348},{"file":"p1349.txt","language":"en","ocr_en":"1349\nVARIETIES OF MANKIND.\naffinity with every other, each has been modified by the introduction of extraneous elements. Thus, in those of Western Europe, there is a considerable admixture of Celtic ; whilst in others there are traces of more barbaric tongues. In fact, there can be little doubt, that Europe had an indigenous population before the immigration of the Indo-German or even of the Celtic tribes ; and of this population it seems most probable that the Lapps and Finns of Scandinavia, and the Euskarians of the Biscayan provinces, are the remnant. There is evidence that the former of these tribes once extended much further south than at present ; and, on the other hand, there is ample proof that the latter had formerly a very extensive distribution through Southern Europe. It has been clearly shown by William Von Humboldt, that the Eusk-arian language, so far from having been derived (as some writers have supposed) from the Celtic, must have been in existence long anterior to the immigration of the Celtic nations into Western Europe; and since that time, it has been shown to have affinities with the Finnish tongue, and through this with the languages of High Asia. It may be surmised, then, that the advance of the Indo-European tribes, from the south-east corner into central Europe, separated that portion of the aboriginal population, which they did not destroy or absorb, into two great divisions ; of which one was gradually pressed northward and eastward, so as to be restricted to Finland and Lapland ; and the other southward and westward, so as to be confined at the earliest historic period to a part of the peninsula of Spain and the South of France, gradually to be driven before the successive irruptions of the Celts, Ramans, Arabians, and other nations, until their scanty remnant found an enduring refuge in the fastnesses of the Pyrenees.* It is curious that the Eusk-arian language should carry out the principle of agglutination to an extent which has no parallel among the languages of the Old World, and which is only surpassed by those of America.\nThe Indo-Germanic race are unquestionably those which are destined to acquire the greatest predominance, not only in the Old World, but in all those newly-found lands wffiich have been discovered by their enterprise. With scarcely any exception, as Dr. Latham has justly remarked, they present an encroaching frontier ; there being no instance of their permanent displacement by any other race, save in the case of the Arab dominion in Spain,\n* This view, which was suggested by the Author (British and Foreign Medical Review, Oct. 1847) without the knowledge that it had been elsewhere propounded, has been put forth with considerable confidence by Dr. Latham (Varieties of Man, p. 551.) as originating with Arndt, and adopted by Rask, distinguished Scandinavian ethnologists. The great antiquity of the Albanian tongue having been fully proved,\"and the circumstances of the tribe having been nearly the same, it is suggested by Dr. Latham that this, too, may be a remnant of the aboriginal Turanian population.\nwhich has long since ceased ; in that of the Turkish dominion in Turkey and Asia Minor, which is evidently destined to expire at no distant period, being now upheld only by extraneous influence ; and in that of the Magyars in Hungary, who only maintain their ground by their complete assimilation to the Indo-Germanic character. It has been already pointed out, however, that the rapid extension of this race is due, not merely to its superior skill in the arts of war and diplomacy, but to a physical cause which tends to extinguish the aboriginal population of many of the inferior races, wherever sexual intercourse takes place between them (p. 1341.).\nII. Asiatic Nations. \u2014 Whilst in Europe the presence of the Arian family is the rule, and that of the Mongolian is the exception, we find in the vast continent of Asia, that the reverse is the case; the presence of the Arian family being the exception, and that of the Mongolian the rule. In fact, although the Celtic and Indo-Germanic races undoubtedly had their origin in Central or Western Asia, yet the tribes which can, with greatest probability, be regarded as the descendants of the ancient stock, are extremely few, and scarcely able to maintain their ground. They are, according to Dr. Latham, the Persians of Northern and Western Persia; the Kurds, the Belachi, the Affghans, the Tajiks of Bokhara, and the Sia-posh. All these speak languages which contain a large proportion of Sanscrit words ; but whether they are so far akin to the Sanscrit in grammatical structure, as to hold to it the same relation as that which the European languages possess, is as yet uncertain. Whether or not the Armenians belong to this group, has not yet been ascertained* It has been generally considered, until recently, that the nations of the great Indian peninsula for the most part belonged to the same stock ; but philological investigation has shown that such a doctrine is certainly untrue with regard to some, and is probably or possibly erroneous with regard to others. The Tamulian, which is the dominant language of Southern India, is undoubtedly not Sanscritic in its origin, although containing an infusion of Sanscritic words, but more closely approximates to the Seriform type. Many of the hill tribes, in different parts of India, speak peculiar dialects, which appear referable to the same stock. And in Dr. Latham\u2019s opinion, the dialects spoken throughout Northern India are to be regarded in a similar light, notwithstanding the large infusion of Sanscritic words which they contain. Viewed under this aspect, the mass of the population of India is\n* It is somewhat remarkable that greater atten tion should not have been paid to the study of the Armenian language ; as the facilities presented by commercial intercourse are not small ; and the isolated position of this nation is one which might lead to the anticipation, that its language might retain the Sanscritic type, with less alteration than that of other nations, which have been more affected by conquest and intermixture of races.\n4r 3","page":1349},{"file":"p1350.txt","language":"en","ocr_en":"1350\nVARIETIES OF MANKIND.\nnot to be regarded as Arian, but as Mongolian ; and the introduction of the Sanscrit language was accomplished by an invading branch of the Arian stock, the only trace of which is to be found in the distinctness of the Brahminical portion of the Hindoo population, in whose religious and other writings the Sanscrit language is still preserved.\nTn the Asiatic group of Indo-Germanic nations, the same general type of conformation presents itself as in the European ; there is, however, a much greater variety of complexion. The mountaineers, even within the tropics, are often as fair as Europeans ; whilst those who live in the level plains, and are exposed to the full heat of the torrid zone, may be of a very deep brown or even black hue. The variety of complexion shown among the Hindoos, even in the Brahminical caste, has been already adverted to. There is but little to remind us of the Mongolian type in the countenances of the Hindoos, which are often remarkable for symmetrical beauty, that only want a more intellectual expression to render them extremely striking ; some traces of it, however, may perhaps be found in the rather prominent zygomatic arches (fig. 828) ;\nFig. 828.\nHindoo Female of Pondicherry. ( From a portrait in M. Geringer\u2019\u2019s \u201c L'Inde Fran\u00e7aise.'\u201d')\nbut this is a character which not unfrequently shows itself strongly in the Arian races (e. g. the Celts) ; and the cranial part of the skull presents no approach to the pyramidal type, being often very regularly elliptical. Among the southern inhabitants of the peninsula, however, a much greater departure from the Caucasian type presents itself ; for not only is\nthe colour darker, but the cheek bones are more prominent, the hair coarse, scanty, and straight, the nose flattened ; and sometimes the lips are very thick, and the jaws project, so that we have indications of a transition towards both the pyramidal and the prognathous types.\nThe south-western portion of Asia is occupied by the Arabs and other Semitic races, which, as will be presently explained, form the transition between the proper Asiatic and proper African nations.\nThe whole remainder of the vast Asiatic continent is occupied by nations which present a sufficiently close approximation to each other, either in physical characters or in language, or in both, to justify their association in one extensive group, under the name of Mongolidce. The typical character of this great family of nations, as seen in a Mongolian or a Tungus from Central Asia, consists in the pyramidal form of the skull {fig. 811. et seq.), with the broad flat face and prominent cheek-bones, and its antero-posterior diameter scarcely exceeding the parietal ; the nose is flat, neither arched nor aquiline ; the eyes drawn upwardsat their outer angle (fig. 814.); the skin of a swarthy yellow ; the hair straight and scanty, and the beard deficient ; and the stature undersized. These characters are softened down in many members of the group ; and may even be entirely wanting, as for instance, in the Circassians and Georgians, (p. 1328.), termed by Dr. Latham the Dioscurian Mongolid\u00e6. Still they are very extensively distributed ; and there is by no means the same amount of variation in complexion, under the influence of temperature, that is seen in the Indo-Germanic races. The following, according to Dr. Latham, are the principal groups into which the Asiatic nations may be arranged : \u2014 1. The Seriform stock, distributed over China, Thibet, the Indo-Chinese peninsula, and the base of the Himalayan range of mountains ; their configuration is Mongolian, softened down (fig. 829.) ; their languages\nFig. 829.\nSkull of a Chinese Ladrone. (From a specimen in the Museum of the Royal College of Surgeons.)\nare aptotic, or with only the rudiments of an inflexion ; and they thus preserve more than","page":1350},{"file":"p1351.txt","language":"en","ocr_en":"1351\nVARIETIES OF MANKIND.\nany other race, the primitive condition of human speech. In their mode of life, they present the phenomenon of a civilization which has attained a considerable degree of development, remaining stationary through a very long period of time, and isolating itself as jealously as possible from the general current of progress. In passing from China towards India, there is a gradual transition in physical and mental characters, between the Chinese and the. Hindoo ; thus the Burmese have more hair and beard, more prominent features, and darker complexions, than the Siamese and Chinese ; and the darkness in complexion increases towards the confines of Bengal. There is, therefore, no such abrupt transition, as shall make it difficult to admit the Seriform origin of the bulk of the Hindoo population, if further investigation of their language should render this connection as probable as it has already been shown to be in the case of the inhabitants of the Dekhan and Ceylon.\u20142. The Turanian stock, including the proper Mongolians of High Asia, the Tungusians, the Turks, and the Ugrians. Among these, the conformity in physical characters is extremely close, the only exception being in the case of the offsets which have migrated into Europe, and which have undergone transformation (as explained at p. 1327.) into the Caucasian type (^g.815^ seq.). The languages of these people are not monosyllabic, but have not undergone any high development ; and they are spoken with very little variation over extensive areas. The general character of the country inhabited by this group is remarkably uniform, being a series of high table-lands or steppes, well adapted for maintaining a nomadic pastoral population. Such is the general habit of these people, and such it has been from our earliest knowledge of them. The Tungusians, however, advance to the Polar Sea, and adopt a manner of life more resembling that of the proper Hyperborean races.\u20143. The Peninsular Mongolid\u00e6, inhabiting the islands and peninsulas of the north-eastern coast of Asia, such as Korea, Japan, and Kamschatka. These are all Mongol in their conformation, but differ from the preceding in the character of their languages, which seem to be, in some cases, extremely po/y-syllabic, always showing a strong tendency to agglutination, and thus showing a transition to the American languages, in which this peculiarity presents its highest development. These tribes are separated from each other, however, by considerable breaks in geographical continuity; some of them lying within the Arctic circle, and others as far south as 26\u00b0 N. L. And they are not less distant in the two extremes of their social development, one section of the group partaking of the civilization of China, and another exhibiting the rudeness of the Sam\u00f6ied. This group is obviously not a typical, but a transitional one.\u20144. Hyperborean Mongolid\u00e6, inhabiting the borders of the Icy Sea, especially in the neighbourhood of the courses of the large rivers, and subsisting especially by fishing and fur-hunting. The area which they occupy\nis not continuous ; the principal tribes, known as the Sam\u00f6iedes, the Yeniseians, and the Yu-kahiri, being separated from each other by the advance of the Northern Ugrians and Tungusians. Their conformation is Mongolian ; but their growth is stunted, and their complexion swarthy; and they bear a very close resemblance to the Laplanders and Esquimaux. It is probable that they will be united when their languages shall have been more fully studied, either with the Turanian or with the Peninsular stocks.\nTurning now to the Syro-Arabian or Semitic nations, which occupy a considerable area in the south-western part of Asia, we encounter a very different type of physical conformation, and a group of languages which is peculiar alike in its structure and in its vocabulary. Generally speaking, the people of this race exhibit a remarkable symmetry of form, and perfection of cranial organisation [fig. 830) ; and it\nFig. 830.\nArab of the Guard of the Imam of Muscat. (From a portrait taken by an officer of JJ Artemise.')\nwas remarked by Baron Larrey, who had ample opportunities for observation during the Egyptian expedition, that experience has proved to him that their psychical character is conformable to this high standard, a great aptitude for intellectual activity being combined with extraordinary acuteness in the use of the organs of sense. There can be no doubt whatever, that the Semitic races have exerted a most important influence on the civilization of the world ; and this not merely by their own early progress in the arts of life (as shown by the extraordinary history of the Assyrian and Babylonian empires, on which so much new light has recently been cast) ; but also by having afforded the channel through which Monotheism was transmitted from the patri-\n4 r 4","page":1351},{"file":"p1352.txt","language":"en","ocr_en":"1352\nVARIETIES OF MANKIND.\narchal times to that of Moses ; by having served as the depository of the Mosaic dispensation, by which that Monotheism was preserved and organised in the Judaical system ; and by having been the centre whence has emanated the fuller light of Christianity, which, in the fulness of time, was exhibited among a people blinded by their own prejudices and selfesteem, to be the regenerator of the nations that as yet knew not God. Scarcely less remarkable is it that the third great Monotheistic system\u2014that of Mahommedanism\u2014which' is essentially a degraded mixture of Judaism and Christianity, should have developed itself amongst the same people, occupying the place, on the one hand, of its Divine prototypes, and on the other, of the various inferior religions whose professors have been brought under Arab sway, and forced to embrace the dogma of their conquerors. Wherever this last change has taken place, it has obviously been for the better ; and there is no more striking example of it, than the superior condition of the African nations which have been thus brought under Mahommedan influence. And it can be scarcely doubted that it is the purpose of Divine Providence, thus to spread and to maintain a Monotheistic system, adapted to the capacities of the people who receive it ; until a higher intellectual and moral development shall render them capable of appreciating the purer light of Christianity.\nThe Semitic languages early attained a considerable development ; but the forms it took were not well adapted for further evolution ; and they present nearly the same type at the present time, as that which is exhibited in the earliest literature which the world possesses : namely, the sacred books of the Hebrew nation. Their alphabet was the earliest in the world ; and their writing is peculiar in passing in the direction contrary to that of other languages, namely, from right to left. \u201c Of the several nations,\u201d remarks Dr. Prichard *, \u201c who are connected by this community of language, some who were formerly celebrated have become nearly extinct ; while others have spread themselves, either as the exiled followers of a persecuted faith, or as the enduring apostles of a victorious one, over the world, and seem destined, through the energy of their invincible mind, to survive to the end of time. The Syrian race scarcely exists ; their language only survives in some districts on the borders of Kurdistan ; everywhere they have been lost under the predominating Arabs. The Homerites in Arabia, if they there exist, are little known ; the Abyssinian Homerites are the only inhabitants of the province of Tigre, to the eastward of the Tacazze, whose idiom still resembles the ancient Gheez. The Arabs, who spread Islam by their victories from the Atlantic to the Ganges, and the Jews, who are wanderers over the whole world, are perhaps now more numerous than were even their forefathers.\u201d Of the difference in complexion that manifests\nitself among the Arabs of Arabia, mention has already been made ; the greatest modifications of the ordinary type present themselves, however, among the African members of the Semitic group, as will presently appear.\nIII. African Nations.\u2014 Of the various nations inhabiting the African continent, those of the Negro type are usually regarded as the most characteristic specimens. But, as Dr. Latham has justly remarked, \u201c no fact is more necessary to be remembered, than the difference between the Negro and African ; a fact which is well verified by reference to the map. Here the true Negro area, occupied by men of the black skin, thick lip, depressed nose, and woolly hair, is exceedingly small; as small in proportion to the rest of the continent, as the area of the district of the stunted Hyperboreans is in Asia, or that of the Lapps in Europe.\u201d When we have separated the region north of the Great Desert, which is mostly occupied by Semitic tribes ; the Great Desert itself, whose scattered population is far from being Negro in many of its features ; the valley of the Nile, at least in its middle and lower portions, including Egypt and Nubia, and even Abyssinia ; and the Kaffre and Hottentot areas south of the equator ; there is only left the western portion of the continent, including the alluvial valleys of the Senegal, the Gambia, and the Niger, with a narrow strip of central Africa, passing eastwards to the alluvial regions of the Upper Nile. Even within this area, the true Negro type of conformation is by no means universally prevalent ; for many of the nations which inhabit it must be ranked as sub-typical Negroes. Our idea of the Negro character, in fact, is almost exclusively founded upon that division of the race which inhabits the low countries near the Slave Coast ; such tribes, indolent and degraded in an extreme degree, are distinguished alike by their extreme ugliness, and by their brutal sensuality. The proper Negro character consists in the combination of a prognathous form of skull, with receding forehead and depressed nose, thick lips, woolly hair, black unctuous skin, and crooked legs ; the facial aspect being such as is represented in figs. 803, 804. Similar characters are met with, again, among the inhabitants of the alluvial regions around Lake Tchad, in the interior ; and some of the tribes in the lowest lands on the eastern side are but little superior. On the other hand, in the immediate neighbourhood of the typical Negroes, but inhabiting higher levels, and presenting a more advanced civilization, are found a number of tribes departing from the Negro type in one or more of its distinctive characters. Thus the race of Iolofs near the Senegal, and the Guber in the interior of Sudan, have woolly hair and deep black complexions, but fine forms and regular features of the European cast {fig. 831) ; the high parts of Senegambia, where the temperature is moderate and even cool at times, are inhabited by Fulahs of a light copper colour; and on nearly the same parallel, but at the\nNatural History of Man, p. 145.","page":1352},{"file":"p1353.txt","language":"en","ocr_en":"1353\nVARIETIES OF MANKIND.\nFig. 831.\nSenegal Chief. ( From a portrait taken ly an officer in the expedition of Capt. Laplace.)\nopposite sides of Africa, are the high plains of Enarea and Kaffa, where the inhabitants are said to be fairer than the natives of Southern Europe. So, again, whenever we hear of a Negro state, whose members have attained any considerable degree of improvement in their social condition, we constantly find that their physical characters deviate considerably from the strongly-marked or exaggerated type of the Negro ; such are the Ashanti, the Sulima, and the Dahomans of Western Africa, of which last nation the king is described by a recent visitor (Lieut. Forbes) as many shades removed from black in his complexion, as having quite an intellectual expression of countenance, and as possessing a remarkable symmetry of figure. It is obvious, too, from the account given by the same observer*, that a very complex social system has developed itself among this people, and that they have made considerable progress in the arts of life, although this has hitherto been only turned to account in furthering the traffic in slaves, of which Dahomey is now the centre, so far as the Slave Coast is concerned. The highest civilization, and the greatest improvement in physical characters, are to be found in those nations which have adopted the Mohammedan religion. This was introduced, three or four centuries since, into the eastern portion of Central Africa ; and it appears that the same people who were then existing in the savage condition still exhibited\nby the pagan nations further south, have now adopted many of the arts and institutions of civilised society, subjecting themselves to governments, practising agriculture, and dwelling in towns of considerable extent, some containing even as many as 30,000 inhabitants \u2014 a circumstance which implies a considerable advancement in industry, and in the resources of subsistence. The languages of the Negro nations, so far as they are known, seem to belong to one group ; although there is a great difficulty in becoming acquainted with them ; in consequence of the entire deficiency of written records. The same cause would of course give a want of fixity to their vocabulary : and thus the dia- 1 lects of two nations descended from a common original, would be likely soon to diverge from each other. Still they all present, so far as is known, the same grade of development, and the same grammatical forms ; and various proofs of their affinity with the Semitic tongues have been developed, these being derived from similarity alike of roots and of construction. The Semitic affinity of the Negro nations is further indicated in a very remarkable manner, by the existence of a variety of superstitions and usages among the Negroes of the Western Coast, which prevail also among the Nilotic races whose Semitic relations are most clear, as well as among branches of the Semitic stock itself ; this is especially the case with the rite of circumcision, which seems to be universally practised throughout the Negro area.\nThe southern portion of the African continent is inhabited by a group of nations which speak various dialects of the Kaffre tongue, and which recede more or less decidedly from the Negro type in physical characfers. Our acquaintance with them, however, is at present very limited ; the interior of South Africa having been as yet scarcely at all explored by civilised man ; and the only people well known to us being those of a few points on the coast, such as Kongo on one side, and Mozambique on the other ; and those of the southernmost extremity, or the region of the Cape. As we pass southwards from the equatorial region, we find a gradual softening down of the proper Negro characters ; and this is greater according to the degree of civilization, and the general improvement in external conditions. Thus, in the people of Kongo {fig. 832), and in those of Mozambique and its neighbourhood {figs. 833, 834), although the hair is woolly and the colour black, yet the skulls are more vaulted {fig. 833) and capacious anteriorly, and have much less of the prognathous character ; the nose is much more prominent, the lips are less thick, and the general expression is milder and more intellectual, than that of the natives of Guinea. When we arrive at the true Kaffres, the race of warlike nomadic people which inhabits the eastern parts of South Africa to the northward of the Hottentots, so great a departure from the Negro type presents itself, that many travellers have\nDahomey and the Dahomans, 1851.","page":1353},{"file":"p1354.txt","language":"en","ocr_en":"1354\nVARIETIES OF MANKIND.\nFig. 832.\nWoman of Kongo. (After R\u00fcgend as.')\nregarded them as having had a different origin. The degree of this departure, however, varies greatly in the different tribes ; for while some of them are black, woolly-headed, decidedly prognathous (fig. 835), and obviously approaching the modified Negroes of Kongo in\nFig. 833.\nMan from Mozambique. (After Rugendas.)\ntheir features and general aspect, others recede considerably both in complexion, features, and form of head from the typical prognathous races, presenting a light brown colour, high forehead, prominent nose, and tall robust stature. The thick lips and frizzled hair are generally retained, however; but the hair is sometimes of a reddish colour, and becomes flowing; and the features may present a European (fig. 836) cast. Even among the tribes which depart most widely from the Negro-type, individuals are found who present a return to it ; and it is interesting to remark,\nFig. 834.\nWoman of the Mongolia tribe\u2014near Mozambique. (After Rugendas.')\nFig. 835.\nSkull of Kaffre. (From a specimen in the Museum of the Royal College of Surgeons.)\nFig. 836.\nKaffre of the Amakosah tribe. (From a portrait by Daniels. )","page":1354},{"file":"p1355.txt","language":"en","ocr_en":"1355\nVARIETIES OF MANKIND.\nthat the people of Delagoa Bay, though of the Kaffre race, as indicated by their language, being degraded by subjugation, approach the people of Guinea in their physical characters. Generally speaking, the Kaf-fres are a people very superior in vigour and capacity to the destitute savages who occupy the insulated regions of Negroland, and how a considerable advance in civilization ; but between the most elevated Kaffre and the most degraded Negro, every possible gradation is presented to us, as we pass northwards and westwards from Kaffraria towards the Guinea coast, so that no line of distinction between them can be founded on physical characters. So, on the eastern side, we pass up until we meet with the same transition. The languages of these people are distinguished by a set of remarkable characters, which have been considered as isolating them from other African tongues. According to Dr. Latham, however, these peculiarities are not so far without precedent elsewhere, as to establish the very decided line of demarcation which some have attempted to draw ; and may be regarded, in fact, as resulting from the fuller development of tendencies, which manifest themselves in other African languages.\nThe Hottentot race (including the Bushman) has, perhaps, so far as regards its physical characters, a better title to be considered as forming a distinct species of the genus Homo than any other ; for not only do these characters present a combination which is not found elsewhere, but that transitional gradation is wanting, which usually presents itself wherever there is a continuous population that has long occupied the same locality. The peculiarities of these people have been already noticed separately ; the following is a general summary of them. The cranium is Mongoli-\nFig. 837.\nform and brachycephalic, the cheek-bones prominent, the jaws somewhat projecting, the eyes oblique, the nose broad and flat, the lips thick, the chin long and pointed ; the complexion is a mixture of black with yellow ochre ; the hair grows in little tufts ; the stature is low, and the limbs are slight ; the buttocks, however, frequently present a steatomatous accumulation. In their cranial characters there is, therefore, an admixture of the Mongolian and the Negro, the former being predominant ; and this resemblance to the people of High Asia is the more remarkable, when it is considered that the physical conditions of the Hottentot country bear a very close correspondence with those of High Asia, the habitation of this people being for the most part on karroos, or elevated terraces and table-lands, over which the vision extends with as piercing a gaze as that of the Mongols. The buttock-hump, or stea-topyga, is not by any means so characteristic of this race as has been imagined ; for, as Mr. Burchell has ascertained, it is only an individual peculiarity, about as frequent as corpulence among European nations ; and it has been met with in other tribes of Southern Africa, as the Makuani of the Mozambique coast. It cannot, therefore, be regarded as affording the least indication of difference of race, but would seem to result from the operation of the same local influences, whatever may be their nature, as produce a similar accumulation of fat in the rumps and tails of the sheep inhabiting the same regions. The peculiar relation of the Bushman tribe to the Hottentot race, has been already explained ; among this degraded people, the same general features present themselves as those which have been described as characteristic of the Hottentots (figs. 837, 838.), but in stature, vigour, and capacity, they are much inferior. A compari-\nFig. 838.\nBushman Female. (From the \u201c Atlas des Mammif\u00e8res of MM. Fred. Cuvier and Geoff. St. Hilaire.')\nson of the cranium of a Bushman (figs. 839, already figured, will clearly indicate that the 840, and 841) with the three typical forms pyramidal skull is the one to which this, bears\nthe greatest resemblance, especially in the * Dahomey and the Dahomans, 1851.\tshortness of the antero-posterior diameter, as","page":1355},{"file":"p1356.txt","language":"en","ocr_en":"Cranium of Bushman. (From a specimen in the Museum of the Royal College of Surgeons.) ]\ncompared with the parietal, and in the breadth and expansion of the malar bones.\nThe ethnological position of the Hottentot race is not altogether clear. There is evidence that it once occupied a more extensive area than it does at present, and that this was much encroached on by the Kaffres, previously to the European colonisation of the Cape. This fact lends weight to a suggestion offered by Dr. Latham, in order to account for the abruptness of the transition between the two races : \u2014 \u201c Let two divisions of a certain class pass into each other by imperceptible degrees, and let one of the central portions of either class spread itself at the expense of the parts belonging to its circumference ; the effect which follows is, that those portions of the area which represent the phenomena of transition are overlaid or overlapped ; and that, instead of two populations coming into contact by imperceptible degrees, they meet as separate classes, with as broad a line of demarcation between their respective representatives, at the peripheries of their respective areas, as there was between their central or typical portions. North-western America illustrates this. The more southern Algonkins have overlaid both the Algonkins of their own section which approached the Esquimaux, and the Esquimaux of the opposite section, which approached the Algonkin. Hence the two populations meet as widely-separated and broadly-distinguished varieties of mankind.\u201d * So, it may be surmised, the bold and warlike Kaffres have overspread themselves through a region whose aboriginal population exhibited a transition between the Hottentot and Kaffre types. \u201c The language of the Hottentots,\u201d says the same learned ethnologist, \u201c can be shown not to be more different from those of the world in general, than they are from each other;\u201d it has not yet, however, been sufficiently studied to enable its true affinities to be known, though some philologists affirm that it is a degraded Kaffre tongue.f\n* Varieties of Mankind, p. 498.\nj- The author thinks it worth while still to repeat a suggestion which he made some years since; namely, that the Hottentot race is the remnant of an earlier migration from High Asia, than that which was the stock of the great bulk of African nations ; and that it has been driven down into the remotest corner of the continent, just as the aboriginal Turanian population of south-western Europe seems\nPassing now to the valley of the Nile, we find a group of nations whose physical characters and languages present a complete and almost uninterrupted gradation from those of the proper African tribes to those of the Semitic group. Under the general designation of Nilotic nations may be included the Gallas, the Nubians, the Bishari, and many subordinate groups. These come into close approximation, both locally and physically, with the Eastern Negroes of the first division, and\nFig. 842.\nSouakiny Chief,\u2014Eastern Nubia. (From a portrait given in \u201c Salt\u2019s Travels.\u201d')\nwith the northern Kaffres of the second. The colour of the Gallas varies from a deep black\nto have been driven back by the Indo-European immigration, and at last to have been limited to the Basque provinces. For anything yet known to the contrary, the structure of the Hottentot language may, like their physical conformation, be more closely related to that of the Turanian stock than to the Semitic, with which the languages of Northern Africa are obviously connected.","page":1356},{"file":"p1357.txt","language":"en","ocr_en":"1357\nVARIETIES OF MANKIND.\nto a brownish yellow ; their stature is tall ; their bodies spare, wiry, and muscular ; their frontal profile vaulted, their nose straight or even arched, their lips moderately full, their hair often hanging over the neck in long twisted plaits. Nearly the same description applies to some of the Nubian tribes (fig. 842), of which the resemblance to the Arab physiognomy becomes very striking, although their colour is jet-black ; and, ;as already shown, there is distinct evidence of their Negro ancestry. The languages of these Nilotic people present an intermediate gradation between the proper Semitic and the proper African ; and all that has been made known by the explorations in these regions, which have been carried on, more or less uninterruptedly, ever since the French expedition into Egypt, tends to break down the line of demarcation which was supposed to separate the African nations from all others. To a similar result have tended all those Egyptological researches which have been carried on with so much ardour during the same period. For a careful examination of the delineations of themselves left to us in the paintings and sculptures of the ancient Egyptians, and of the crania preserved in their sepulchres, leaves no reasonable doubt, that in their physiognomy and complexion they were essentially African ; although very marked varieties in cranial conformation, and in the hue of their surface, appear to have existed amongst them. The Copts, or existing natives of Egypt, seem, on the whole, pretty nearly to represent their physical characters, although in a condition of comparative degradation, owing to the state of subjection to which they have been reduced ; and although the existing Coptic lan-\nFig. 843.\nguage has been undoubtedly changed from its original form by the successive colonizations and conquests to which the country has been subjected, yet it still shows a marked affinity with the proper African languages in certain peculiarities of its construction.\nLastly, the northern and north-western portion of the African continent is occupied by tribes whose Semitic origin is undoubted. Several immigrations appear to have taken place at different times from the Syro-Arabian stock ; but that which has most claim to the title of an aboriginal population, is that of which the Berber races (from which the north-west of Africa received the designation of Barbary) may be regarded as the types ; the Kabyles of Algiers and Tunis (the people of Abd-el-Kader), the Tuaryks of Sahara, and the Shelahs or mountaineers of Southern Morocco, being branches of the same stock ; as were also, most probably, the Guanches or ancient population of the Canary Islands. These people all speak dialects of a language, which has been shown by Prof. Newman to be an offset from the Semitic : and whilst the complexion, and even the hair and physiognomy, of those which approach the Negro area, present a remarkable approximation to those characteristic of the Negro, those of the northern and more elevated districts retain the Caucasian type, and some of them are quite fair in skin, and European n feature. But subsequently to the settlement of these tribes in the regions they still inhabit, there have been colonizations by Phoenicians and true Arabs ; and these immigrants have for the most part remained distinct from the aboriginal population (y%s. 843.844),\nFig. 844.\nAlgerine Arabs of the Mozabite tribe. (From portraits taken under the direction of Prof. Milne-Edwardsf\ntheir languages being divergent, and their Notwithstanding its Semitic affinities, the habits and grade of civilisation different. Such language of the North-African aborigines is were the sovereignties of Morocco, Algiers, considered by Dr. Latham as having affinities and Tunis, which brought the aboriginal tribes also with the proper African tongues, and as under nominal subjection to themselves, having been isolated from them without suf-","page":1357},{"file":"p1358.txt","language":"en","ocr_en":"1358\nVARIETIES OF MANKIND.\nficient reason ; and if this be the case, another link of transition exists, which, with those previously named, brings the two groups into such relations, that their separation cannot be justified. By Dr. Latham, accordingly, the Syro-Arabian or Semitic race is ranked with the African under the general designation Atlantid\u0153.\nIV. American Nations.\u2014The aboriginal inhabitants of America have been considered by some ethnologists as a department of the human family very distinct from the inhabitants of the Old World ; and attempts have been frequently made to define them as a race by physical characters. But these attempts have been founded upon a very imperfect acquaintance with the nations peopling this vast continent ; for, taken in the aggregate, they are by no means uniform either in physical qualities, in intellectual endowments, moral character, or grade of civilisational development; nor is the line of distinction between them and the rest of mankind nearly so obvious or strongly marked as is usually imagined. Thus the native Americans have been described as \u201c red-men ; \u201d but there are tribes equally red, and perhaps more deserving that epithet, in Africa and Polynesia ; and the American nations are by no means all of a red or copper hue, some being as fair as many European people, others being brown or yellow, and others nearly, if not quite, as black as the Negroes of Africa. Again, it has been attempted by anatomists to distinguish the American races by a certain configuration of skull and form of features ; and\nFig. 845.\nWf\nIndian of the Oto tribe, \u2014 basin of the Mississippi. (From the \u201c Atlas du Voyage du Prince de Neuwied.\u201d)\nNotwithstanding this diversity in their physical characters, however, there is strong evidence that the American nations constitute one natural family, bound together by community of descent. This appears from the\neven Dr. Morton, in his splendid work entitled \u201c Crania Americana,\u201d has given his authority in support of the opinion, that such distinctive characters are to be found \u201c in the squared or rounded head, the flattened and vertical occiput, the high cheek-bones, the ponderous maxillae, the large quadrangular orbits, and the low receding forehead.\u201d Nevertheless, even he is obliged to admit that very considerable diversities present themselves in the cranial conformation of the American nations ; and he altogether excludes the Esquimaux, who, according to the evidence of language, must be regarded as being as truly an American people as any other, in spite of their obvious conformity to the Mongolian type of cranial configuration. And it will be observed that many of the characters just enumerated are those of the Mongolian cranium ; a decided approximation to which may be seen among several tribes, whose dwelling is much further south than that of the Esquimaux. The testimony of travellers who have visited parts of the continent remote from each other, and who have scrutinized with observant eyes the physiognomy and form of head, not in individuals only, but in nations, is very decided as to the marked varieties in configuration which present themselves among these ; thus, says that eminent zoologist, M. D\u2019Orbigny, \u201c A Peruvian is more different from a Patagonian, and a Patagonian from a Guarani, than is a Greek from an Ethiopian or a Mongolian.\u201d The accompanying figures present examples of this diversity {figs. 845 and 846).\nFig. 846.\nSouth American of the Charruan tribe. (From a portrait by Werner, in the Museum of Paris.')\nremarkable relationship which has been discovered among their languages ; not, however, in their words or even their roots,but in their grammatical construction. In regard to vocabulary, indeed, there are few parts of the","page":1358},{"file":"p1359.txt","language":"en","ocr_en":"1359\nVARIETIES OF MANKIND.\nFig. 847.\nSouth American of the Puri tribe,\u2014 interior of Brazil. (After Rugendas.)\nglobe in which so many dialects, or even distinct languages, are spoken within such limited areas ; and thus, if difference in this respect be considered as a sufficient reason for denying the mutual affinity of the races, the number of separate stocks must be enormously multiplied. On the other hand, the mutual relationship just indicated, which consists more particularly in the very remarkable agglutination of words or portions of words, has been found in all the American languages which have been carefully examined, including some of the most important dialects spoken in parts of the continent very remote from each other. And it is easily shown that this practice, carried on without any regular system, but according to the wants and caprices of each detached community, will, in the absence of such a literature as gives fixity to a language, almost necessarily induce such changes, that two offsets of the same stock, developing themselves under different circumstances, shall cease in a few generations to be mutually intelligible. There are other causes, too, in the character of the people themselves, and in the mode in which they employ language, which tend to introduce such variations. Their speech is, for the most part, rather an expression of their own ideas and emotions, than a reflex of external things, \u2014 much more subjective than objective ; and hence their names for the most familiar objects, or the simplest ideas, are long compound words or epithets, which are in striking contrast with the brief terms employed for the same purposes by most other nations. This feature in their phraseology seems common to all the American languages ; and it is strikingly indicative of a fundamental peculiarity in the psychical character of the people, namely, a predominance of the imaginative and rhetorical disposition, over the mere sensuousness which is observable among most nations that have\nFig. 848.\nSouth American of the Achagua tribe,\u2014basin of the Orinoco. (From a portrait by M. Boulin.')\nattained to a similar grade of material progress. Those, indeed, who are most familiar with the psychical nature of the aborigines of America, have been struck with the manifestations they present of greater energy and mental vigour, of a more reflective nature, of greater fortitude, and of more consistent perseverance in their various pursuits and enterprises, than are to be met with among any of the aboriginal nations of the Old World ; and these peculiarities are in great part due to the intensity of their selfish emotions, which exhibits itself in the sullen and unsocial character, the proud apathetic endurance, the intensity of hatred and revenge, the feeble influence of the benevolent affections, and the deep malice-concealing dissimulation, which are so remarkable in the dwellers amid the dark solitudes of the American forests. Among many of the American nations, moreover, traces have been observed of ancient institutions,\u2014 complicated forms of government, regulated despotisms or monarchies, privileged orders, hierarchical and sacerdotal ordinances, systematic laws (the result of reflection and a settled purpose) connected with marriage, inheritance, family relationships, &c. and other customs, \u2014 that mark a very early progress in social development, the forms of which are in great degree peculiar to them. Their opinions, moreover, respecting a future state, and the nature and attributes of invisible agents, are strikingly different from those of nations who have never emerged from primitive barbarism. They have had in use, moreover, from time immemorial, cultivated plants and domestic animals, different from those of the Old World ; and their earliest traditions refer the knowledge of these to some fabulous person, who descended from the gods, or who suddenly made his appearance among their ancestors ; thus indicating the remoteness of the era of their separation","page":1359},{"file":"p1360.txt","language":"en","ocr_en":"1360\nVARIETIES OF MANKIND.\nfrom the inhabitants of the Old World, who have similar mythical legends in regard to the introducers of their first arts and acquirements.\nAbundant evidence is afforded, by architectural and other remains still existing, as well as by the accounts of the early Spanish historians, of the high degree of civilisation which some of the nations of America had attained, previously to the European immigration, especially in the warmer regions of that continent. Thus the natives of Mexico had erected stupendous edifices, which rivalled those of Egypt ; and although they did not attain to the greatest of human inventions,\u2014 that of symbols representing the sounds of words, \u2014 they had long aspired after it, and had contrived a method of recording events and of handing down to memory the passages of their ancient history. They had even made great advances in science, and had a solar year with intercalations on the principle of the Roman calendar. They were diligent cultivators of the ground, and also expert miners and workers in metals ; even astonishing the workmen of Europe with their skill in setting gems. They appear, too, to have been influenced by a deep sentiment of religion, and to have had a very stately and majestic ceremonial. Nevertheless, they do not seem to have derived from these advances in civilisation, any moral improvement, or any mitigation of that sullen malignity which seems to be the general character of the native tribes of the New World ; and their religion was far from having an exalting influence, since their gods had no attribute of clemency or mercy, but were invested with the worst forms of their own dark passions. In Peru, also, we find remains of Cyclopean structures erected during the government of the Incas, which bear comparison with those of ancient Egypt ; and the wonder is increased when it is recollected, that no beast of burden save the llama existed in Peru before the Spanish invasion. At a time when there were no public highways in Britain but such as were relics of Roman greatness, there were roads of 1500 miles in length in the empire of Peru, carried over heights which overtop the Peak of Teneriffe. The ancient Peruvians were ignorant of the manner of forming an arch ; but they had constructed suspension-bridges over frightful ravines. They had no implements of iron; but they could move blocks of stone as huge as the Sphinxes and Memnons of Egypt.\nEverything, then, seems to indicate one of two things ; either that the American races are descended from a stock originally distinct from that of any part of the Old World, or that, having had a common origin with the aborigines of Asia and Europe, they have existed as a separate family of nations from a very early period in the history of the race. This question will be considered hereafter ; but it must not here be left unnoticed, that several of the tribes of the Western coast of America present a striking physical resemblance to the\nPeninsular Mongols ; and that there are indications of communication between them, at a comparatively late period.*\nThis brief account of the American races would be incomplete, without a notice of one of their most remarkable customs, \u2014 that of altering the form of the skull by artificial compression \u2014 which may be traced in different parts, both of the northern and southern divisions of the continent. This flattening was vertical in some instances, horizontal in others. Of the former, Dr. Morton figures examples, in his \u201c Crania Americana,\u201d from the tribe of Natchez Indians (which appears to have been a branch of the Toltecan family) that was exterminated by the French in the year 1730. The compression was effected by means of a bag of sand placed upon the forehead, whilst the occiput lay upon a sort of mould, of which it gradually took the form under the slow but constant influence of this pressure. Some curious bas-reliefs, executed by the Toltecans during their sojourn in Mexico, show that the practice prevailed amongst the most civilised portion of that race. The horizontal flattening is practised at the present time by the Chinooks and other tribes inhabiting the neighbourhood of the Columbia river ; the mode in which it is accomplished varying considerably in the different tribes, but the general effect being the same. So highly is this deformity valued by them, that their slaves are not allowed to practise it ; and yet the process by which it is induced often gives rise to ulceration of the scalp, and not unfrequently to death. In one of the skulls figured by Dr. Morton, the vertical diameter is reduced to little more than four inches, the top of the cranium presents a flattened arch not far removed from a horizontal plane, and the face is protruded until the facial angle is reduced to 60\u00b0, probably the lowest grade ever observed in a human skull ; the compression has also destroyed in a remarkable degree the lateral symmetry. Yet the capacity of the cranium is not altered by the process ; and the \u201c flat-head \u201d Indians are certainly not deficient in any of the mental qualities of their race. Both kinds of flattening appear to have been practised by the ancient Peruvians ; in whose sepulchres are found vast numbers of crania, presenting such different degrees of departure from what seems to have been the normal form, that it is not easy to find one which can be positively affirmed to be unaltered. A characteristic example of the effect produced by the process of horizontal flattening is given in figs. 849, 850, 851 ; which represents a skull closely resembling that of a flat-head Indian of the Columbia river. It seems not improbable that the horizontal flattening was practised anteriorly to the advent of the Incas, which may be dated at about the year 1100 ; and that the vertical flattening was introduced by them. It seems to have been\n* See Humboldt\u2019s \u201cViews of Nature\u201d (Bohn\u2019s edition), pp. 131\u2014133.","page":1360},{"file":"p1361.txt","language":"en","ocr_en":"VARIETIES OF MANKIND.\n1361\nArtificially-compressed Cranium from Titicaca.\t(From a specimen in the Museum of the Royal College of\nSurgeons.')\ncontinued among the Peruvians for some time after, their conquest by the Spaniards ; for the Ecclesiastical Court of Lima passed a decree in the year 1585, forbidding parents, under certain specified penalties, to compress or distort the heads of their children in the various modes which were then in vogue. The practice still exists among certain tribes of South American Indians ; and seems to be regarded in much the same light with the artificial compression of the foot by the Chinese, or of the waist by the French and English,\u2014namely, as an artificial development of a natural beauty.\nV. Oceanic Nation. \u2014 The vast Oceanic area, extending in longitude from Madagascar on the one side, to Easter Island (half way between Asia and America) on the other; and in latitude from Formosa to New Zealand, including the numerous islands of the Indian and Polynesian archipelagoes, and the great island-continent of Australia, is peopled by tribes the greater part of which are undoubtedly related to each other very intimately, and have no near affinities with those of any other region. The only part of the mainland of Asia which is inhabited by an Oceanic tribe, is the Peninsula of Malacca ; and there is far more reason to think that this tribe has migrated to that locality from the neighbouring part of Oceania, than that it represents the original stock and line of migration of the Oceanic races. In the physical characters of the Oceanic tribes, two typical varieties present themselves ; and these may be designated as the Malabo-Polynesian, and the Negrito.\nThe Malayo-Polynesians present a nearer approach to the Mongolian type than to aqy other ; but they must be compared rather with the modified Mongols of the south-east portion of the Asiatic continent, than with the proper Turanian stock. Their complexion is yellow, olive, brunette, or brown, rarely or never darkening into black ; their hair, often long, is usually black and straight ; the face is usually somewhat flat, the cheek-bones high, and the antero-posterior diameter of the skull short ; but there is often a tendency to the\nVOL. IV.\nprognathous character, such as is shown among the inferior Hindoos. This division of the Oceanic races occupies the greater part of the Indian Archipelago, and the whole of the Polynesian ; but it does not exist in New Guinea, Australia, Tasmania, New Ireland, or the islands between it and New Caledonia, which are peopled exclusively by Negritos. That the tribes thus widely dispersed are all descendants of one and the same stock, and belong to the same race, seems distinctly proved by the affinities of their languages ; which, although presenting considerable modifications (as might be naturally expected from a prolonged isolation, and from the entire absence of a literature), yet accord, as has been proved by William Humboldt, in many of their primary words, and in their general plan of construction. This mutual relationship is the closest among the Malayan dialects of the Indian Archipelago on the one hand, and among the tongues spoken by the various Poly-nesian islanders on the other ; but these two groups are also undoubtedly related to one another, in such a manner as to constitute but one family of languages.\u2014The proper Malays are, for the most part, a people of short and slender stature, and small limbs, but well-formed and vigorous ; they have flat faces, somewhat oblique eyes, and features resembling the Chinese; the hue of their complexion, however, is considerably deeper, but is not so dark as that of the Hindoos, yellow being still a large ingredient. These characters, however, are far from being uniformly exhibited by the whole Malayan branch ; and in particular it is to be remarked that a tendency to the prognathous type occasionally show\u2019s itself, as in the skull of a Bugis of Celebes, described by Blumenbach.\u2014Between the Malayan and the proper Polynesian area is a small group, including the Pelew, Caroline, and Marianne islands, the inhabitants of which are even more conformable to the Mongo'ian type than are either the true Malays or the proper Polynesians ; these are termed by Dr. Prichard, Micronesians. A consideration of the probable lines of that migration which\n4 s","page":1361},{"file":"p1362.txt","language":"en","ocr_en":"362\tVARIETIES OF MANKIND.\nmust be admitted to have taken place, unless every island is supposed to have had its own independent stock, has led Dr. Latham to the conclusion that the Micronesian group was peopled before the Polynesian area. \u2014 The proper Polynesian branch presents such a wide diversity in physical characters, that if it were not for the unquestionable community of language, usages, &c., it might be thought to consist of several races, as distinct from each other as they are from the Malayan branch. Thus the Tahitians and Marquesans are tall and well made; their figures combine grace and vigour ; the skulls are usually as symmetrical as those of most Europeans ; and their physiognomy presents much of the European cast, there being only a slight flattening of the nose, expansion of the nostrils, and thickening of the lips, to indicate a degradation, which is rather in the Negro than in the Mongolian direction {fig. 850.). The coming. 850.\nTahitian Female. ( From a portrait by an officer of \u201c L' Artemise.\u201d')\nplexion, especially in the females of the higher classes, who are sheltered from the wind and sun, is of a clear olive, or brunette, such as is common among the natives of Southern Europe ; and the hair, though generally black, is sometimes brown or auburn, or even red or flaxen. Among other tribes, as the Sandwich Islanders, the New Zealanders, and the Tonga and Friendly islanders, there are greater diversities of hue and conformation (fig. 851.); some being of a copper-brown colour; others, nearly black; others, olive ; and others, almost\nwhite ; the fairer races are generally taller and more vigorous, whilst the darker are inferior in stature and figure. Many of these varieties present themselves in a single community,\nFig. 851.\nNew Zealander. (From a portrait by Earle.')\nsuch as that of New Zealand, and are so strongly marked as to have led to the idea that the difference is due to an intermixture of races ; but the unity of language, and the absence of any other indication, prevent such a supposition from possessing the least claim to reception. It is a most remarkable fact that the Madecassians, or natives of Madagascar, speak a language which is obviously derived from the Malayan stock, being most nearly allied to that of the Philippine Islands ; and some of the multiform population of that island bear a striking resemblance to Malays, whilst others seem more allied (as might be expected) to the African nations of the mainland. At present, the character and origin of the Madecassian population is one of the doubtful questions of ethnology.\nThe Negrito race presents a marked approximation to the physical characters of the true Negro. The skull is of the prognathous type ; the nose is flattened, the nostrils expanded laterally, the lips thickened, and the complexion a deep brown, or even black. The character of the hair varies considerably ; for in some cases it is long and straight ( fig. 827.) ; and in others, crisp and frizzly ; and in others, even woolly (figs. 805,806.). By Dr. Prichard and others a distinction was drawn between those with straight, and those with woolly hair; but the validity of this can scarcely be maintained, since it appears that the very same people may present one or the other kind of hair, according, as it would seem, to the climatic and other conditions under which they exist. The Negrito race not only inhabits the area which is more exclusively its own, but is also believed to exist in","page":1362},{"file":"p1363.txt","language":"en","ocr_en":"1363\nVARIETIES OF MANKIND.\nthe interior of many of the larger islands of the Indian Archipelago ; it is not always certain, however, whether the people whose presence there is reported, are Negritoes or dark\nFg. 852.\nPortrait of Ourou-Mare, an Australian Chief. (From the \u201c Atlas du Voyage au Terres Austra.les.\u201d')\nMalays. There are many indications, indeed that the Malayo-Polynesian and Negrito races are not really so distinct, as the marked dissimilarity of their respective physical types, and the complete want of conformity between their languages, would make it appear. For as, on the one hand, some of the subdivisions of the former present a decided tendency towards the prognathous character, and the depth of complexion, which are typical of the latter, so among the latter we do find a lighter shade of skin, a greater symmetry of skull, and a considerable improvement in form and feature, not unfrequently displaying themselves ; as is the case, for example, with some of the Papuans, or inhabitants of New Guinea, and even occasionally with the Australian aborigines, notwithstanding that the physiognomy of the latter generally exhibits a very manifest-degradation (flg. 852.) The relations of the language of the different branches of this race to each other, and to other languages, have not yet been clearly developed. They appear, however, to possess a general community of structure, with differences in the vocabulary; and such differences present themselves very prominently among some of the languages of Australian tribes, whose common origin cannot be questioned. According to Dr. Latham, they contain a considerable infusion of Malay words ; but this is scarcely enough to establish their community of origin with the languages of the Malayo-Polynesian stock. Some other affinities have been pointed out by Dr. Prichard ; but these, it is remarkable, are not so intimate as those which subsist between the Australian and the Tamulian of Southern\nIndia. Remote as the connection seems, this circumstance adds weight to the idea, that the native Australians are an offset from that southern branch of the great nomadic stock of Central Asia, which seems early to have spread itself through the Indian and Indo-Chinese peninsula.\nIt is commonly beloved that there is no people, excepting the most degraded of the Negroes and the Bushmen of the Cape, whose physical condition is so miserable, or whose mental development is so low, as that of the Australian aborigines ; but the testimony of those who have visited them in their native haunts, where as yet they have been uncontaminated by contact with Europeans, and have not suffered from the deprivation of the land which affords them the means of subsistence, is veiy decided i.i regard to the exaggeration which has prevailed on this point. In particular it may be remarked, that, although they have less susceptibility than exists among many other rude nations to religious impressions, yet it is certain that they are not destitute (as some have represented them to be) of all idea of a God ; they even seem to have a notion of a future state, and a belief in good and evil angels. They have likewise a superstitious belief in magicians or sorcerers ; a belief which seems to attain its highest point among the nations of High Asia. Many complex and singular institutions, especially relating to the tenure of property, exist among them ; to which the neavest approach elsewhere is presented by the North American Indians.\nLooking, then, to the great diversity which exists among the subordinate groups of which both these divisions consist, and their tendency to mutual approximation, it cannot be shown that any sufficient reason exists for isolating them from each other ; and, as already remarked, there seems no medium between the supposition that each island had its aboriginal pair or pairs, and the doctrine that the whole of Oceania has been peopled from a common stock. Looking, again, to the very marked approximation which is presented by certain Oceanic tribes to the Mongolian type, and this in a locality which, on other grounds, might be regarded as having received the first stream of migration, the possibility, to say the least, can scarcely be denied, that the main-land furnished the original stock, which has undergone various transformations subsequently to its first dispersion ; these having been the result of climatic influence and mode of life, and having been chiefly influenced as to degree, by the length of time during which the transforming causes have been in operation. At any rate it may be safely affirmed, that there is no physical peculiarity which entitles the Oceanic races to rank as a group, which must have necessarily had an original stock distinct from that of the continental nations.\nGeneral Recapitulation.\nOn the whole then, the result of the extensive range of inquiries, of which an out-\n4 s 2","page":1363},{"file":"p1364.txt","language":"en","ocr_en":"1364\nVARIETIES OF MANKIND.\nline has now been given, may be stated as follows : \u2014\n1.\tThe extremest differences from each other, or from a common stock, presented by the races of Mankind, in regard alike to physical, physiological, and psychological peculiarities, are not greater in degree than those which are known to arise amongst other species of animals possessed of a similar adaptive capacity, under the influence of changes in external conditions ; and they differ only in degree, not in kind, from those of whose origin in a change of external conditions, in the case of mankind, we have adequate evidence.\n2.\tIn whatever mode the types of the principal varieties are selected, they are found to be connected by intermediate or transitional gradations ; the descendants of each principal stock exhibiting, in a greater or less degree, a capability of approximation to the characters of others.\n3.\tThere is nothing in these diversities, therefore, to justify the erection of specific distinctions among the different races of Mankind ; and, whilst a probability of the unity of their original stock may consequently be said to exist, all scientific evidence points ta the conclusion, that, if the original stocks were multiple, they must have had attributes essentially the same.\n4.\tThe supposition of a number of distinct \u201c protoplasts,\u201d one for each principal region of the globe, is not required to account for the extension of the human family over its area, and it does not afford any assistance in accounting for the phenomena of their existing distribution ; since each principal geographical area contains races of very diversified physical characters, the affinity of whose languages makes it next to certain that they must have had a common descent.\n5.\tThe evidence of philological research decidedly tends to the conclusion, that such affinities exist between the earliest known stocks of the principal groups of languages now and heretofore in use, as can only be reasonably accounted for on the hypothesis of their common origin, and the consequent radiation of the whole species from one centre. What that centre is likely to have been, is a legitimate object of inquiry ; and the following, which have long been regarded by the author as the most probable deductions from modern Ethnographical research in relation to this subject, are now submitted with additional confidence, on account of the confirmation which they have received from the most recent investigations, and, in particular, from their conformity with the arrangement which Dr. Latham\u2019s linguistic researches have led him to adopt.\nThe stock from W\u2019hich the globe was originally peopled, is probably more nearly represented at this time by the Turanians of High Asia than by any other ; and some part of that region was probably their primary seat. It is among the Mongols and their allies, that that combination of physical attributes which is best adapted to the exigencies of a nomadic\nlife, and that constitution which renders a nomadic life a necessity of their nature, most characteristically present themselves. The bodily system of these people possesses a vigour and adaptiveness, which enables it to flourish under all the diversities of climate to which their wandering propensities conduct them ; and they can accommodate their mode of life, without any great departure from their characteristic nomadism, to a great variety of external circumstances. Moreover, the geographical relations of High Asia make it the most central spot on the whole globe, for the radiation of Man to every corner of the habitable world ; its connections with all other lands are such as are possessed by no other region ; while its climate is so intermediate between that of the frigid and that of the torrid zones, that the passage into either is without any violent transition ; and, as a matter of fact, we find that, while the Tungu-sians and Ugrians have carried the Turanian stock to the shores of the Polar Sea, a Tartar tribe has made itself master of China, and governs the whole of the south-east of Asia, even to the Indian Ocean. This \u00e0 priori argument, however, would be worth very little, if we did not find it in correspondence with the very curious fact, that the most ancient inhabitants of nearly every part of the globe are connected with the nations of High Asia, more or less closely, by affinity of language or of physical characters. This we have seen to be the case, not merely with the Seriform stock of Southern Asia and the Hyperborean and Peninsular Mongols of the north and north-east, but also with the aboriginal people of Northern and Southern Europe, with those of the Caucasus, and with the first settlers of the Indian Archipelago. Not less complete is the transition to the American nations; for whilst, on the one hand, the Esquimaux forms the link of connection, agreeing in physical character with the Hyperborean Mongols, and in language with the mass of the proper American nations, increased acquaintance with the languages of the latter, and with the languages of the Northern Asiatics, has confirmed the suggestion long since made, that they are constructed upon a plan essentially the same; the tendency to agglutination, which is less manifested in the more immediate descendants of the parent-stock, being most fully carried out in its offsets, the Euskarian of the Basque provinces, the languages of the Peninsular Mongolid\u00e6, and the American tongues. The only region regarding which there is not the same amount of evidence, is Africa. But we have seen reason to regard the whole group of African nations as connected, through the Semitic stock, with the Asiatic races ; and all the knowledge recently acquired of the language of Ancient Egypt*, together with all the information gained by Major Rawlinson and\n* See the memoir by the Chevalier Bunsen, \u201c On the results of the recent Egyptian Researches in reference to Asiatic and African Ethnology, and the Classification of Languages,\u201d in the Reports of the British Association for 1847.","page":1364},{"file":"p1365.txt","language":"en","ocr_en":"1365\nVARIETIES OF MANKIND.\nother decipherers of the most ancient inscriptions in the south-west of Asia, tends towards the conclusion, that the languages of the African nations are derived from the same fundamental stock with those of the Arian and Turanian, the separation having taken place when they were as yet in that early stage of development, which has remained stereotyped (so to speak) in the Chinese and other Seri-form tongues. Looking at the African population under this aspect, we may fairly imagine it to have been first derived from immigrants by no means remote from the Turanian stock ; these gradually spreading themselves over the entire continent, became gradually modified in their physical characters by the new circumstances in which they found themselves ; and whilst the dwellers in the Nile valley advanced in civilization and in intellectual development, and became assimilated in cranial characters to the other races surrounding the Mediterranean sea, those of Central, Western, and Southern Africa underwent a degradation into the prognathous type, similar to that which has affected the earlier settlers in Oceania, and to which some approach is seen in Southern India. Viewed under this aspect, the re-appearance of the Mongolian type of conformation among the Hottentots of Southern Africa is extremely significant ; for, although they are Africans by immediate descent, yet the characters of their remoter ancestry reappear, so soon as a correspondence in physical conditions favours their reproduction.\nIn certain spots of the globe thus peopled with races derived from a common centre, varieties in physical conformation appear to have sprung up, which, in a scanty and scattered population, would have a far greater tendency to perpetuation than is now anywhere exhibited (see p. 1312); new and more refined languages were originated ; local developments of higher forms of civilization occurred ; and subordinate centres were thus formed, from which more limited radiations have subsequently taken place, impressing their own features of civilization upon the countries through which they have spread. Thus we have, at a very early period, indications of the Egyptian, the Syro-Arabian, the Arian, the Indo-Chinese, the Mexican, and the Peruvian races, preserved to us in their architectural remains, or in their written records ; and although some of these may possibly have been mutually connected at their origin, yet they seem to have been very early separated, and to have attained their fullest development independently of each other. The subsequent migrations of certain of these races, or of offsets from them, have entirely changed their original distribution. The Arab race has extended itself through Northern and even Central Africa, over Southern Asia, and even into the Indian Archipelago. But the Arian has displaced the aboriginal population from almost every part of Europe, and has there formed a secondary centre ol\nradiation, whilst its original stock has been almost obliterated. It is obviously a stock which attains its fullest development under the influence of a moderate temperature ; and only, therefore, when it exchanged its original seat for the more favourable influences of European climate, did it manifest its remarkable capabilities. It can scarcely be doubted that from this race, or from a mixed race developed between it and their aboriginal populations, America and Oceania are destined to be re-peopled ; the destiny of Asia and Africa, however, seems more obscure. In the former country, the primitive races possess a considerable amount of self-sustaining vigour ; and in the latter, they exhibit an adaptiveness to its peculiarities of climate, which will perhaps never be acquired by Europeans. Moreover, whilst the American and Oceanic races appear doomed to extinction as pure races, wherever they come into contact with Europeans, there is no evidence that such is the case with those of Mongolian or of African descent ; the latter, indeed, hold their ground with remarkable tenacity, and we may not improbably regard them as destined, under the influence of Christian civilization, to bear an important part in the future history of Mankind. (See p. 1344.)\nAddendum.\u2014[Since the former part of this article has been in print, the statements of Count Strzelecki, cited in p. 1341, have been pointedly contradicted, as regards the aboriginal females of Australia, by Dr. T. R. H. Thompson (surgeon, r.n.), who states as the result of personal inquiries among several different tribes, that for a native female to bear children to a native male, after having borne half-caste children to an European father, is by no means an uncommon occurrence. He admits that wherever European settlers are commingled with the aborigines in Australia, the native race disappears. This however, he maintains, does not arise from \u201cany deviation of nature\u2019s laws but because the European, wherever he takes with him his civilization, takes with him his vices also; so that drunkenness and syphilitic diseases, which soon become rife among the neighbouring population, speedily cause their decline. Dr. Brown allows that the diminution is partly caused by the comparative infecundity of the females who have cohabited with Europeans ; but he accounts for this by attributing it to the change of life to which she is subjected.\n\u201c From living in a state of nature, with irregular and uncertain diet, exposed to every vicissitude of climate, with no other protection than a few kangaroo skins, or a roll of bark, or of the \u2018tulka,\u2019 she enters on a more regular life, partakes of regular meals, and sleeps no longer exposed. But even with this alteration for the better, she does not bear to the white man more prolifically than to her native husband ; on the contrary, her fecundity appears to decrease,\u2014 for, on partaking of the white man\u2019s comforts, she is a recipient of his vices; she passes much of her time in a half inebriated","page":1365},{"file":"p1366.txt","language":"en","ocr_en":"1366\nVARIETIES OF MANKIND.\nstate, smoking tobacco and drinking ardent spirits whenever they can be procured. Indeed, it is well known, that among the chief inducements for the native female to remain with a European, are the rum and tobacco with which she is supplied ad libitum. Can we then wonder, if, after some years spent in a manner which must militate against her capabilities for procreating, more than her previous rude mode of life, she returns to her tribe with a broken constitution, and probably past the usual term of life for conception (they seldom bear children after thirty years of age) to prove in such instances sterile?\u201d*\nThe same explanation is probably applicable to the case of the other Aboriginal races adverted to by Count Strzelecki ; and, if it be the correct representation of facts, it altogether destroys the force of any argument which might be raised upon the infertility of the native females after having borne children to Europeans, in favour of the specific difference of the races.]\nBibliography.\u2014 For the facts of the latter part of this article, the author has relied in great part on the learned and elaborate treatises of Dr. Prichard, whose \u201c Researches into the Physical History of Mankind\u201d (3rd edit., London, 1836-1847), will long hold its rank as a most complete and masterly treatise on Ethnology. His smaller work, \u201c The Natural History of Man\u201d (London, 1848), though chiefly an abridgement of the preceding, contains in its supplement some additional information of value. The author has also derived much assistance from Dr. Latham\u2019s more recent treatise, \u201c Natural History of the Varieties of Man,\u201d (London, 1850). A large part of the materials of the earlier portion of the article, however, have been drawn direct from original sources.\nThe Bibliography of the subject., to be complete, must include a most extensive catalogue, not only of special treatises in various departments of Ethnology, but also of Voyages and Travels, and of Philological works and memoirs. The following are selected as having the greatest claims to particular mention :\u2014Abel-R\u00e9musat, Recherches sur les Langues Tartares, Paris, 1820. Adelung, Mithridates, oder allgemeine Sprachenkunde, Berlin, 1806 \u20141817. Balbi, Atlas Ethnologique, Paris, 1826. Barrow, Travels in the interior of South Africa, London, 1801\u20141804. Beechey, Voyage to the Pacific Ocean and Behring\u2019s Straits, London, 1831. Bennett, Wanderings in New South Wales, &c., London, 1834. Blumenbach, Institutiones Physiologic\u00e6, G\u00f6ttingen, 1787. De Generis humani Varietate Nativa, Gottingen, 1795. Collectio Craniorum di-versarum Gentium, decades 1\u20147, G\u00f6ttingen 1790\u2014 1828. Bopp, Vergleichende Grammatik, Berlin, 1833\u20141842. Borg de St. Vincent, Voyage dans les quatre Iles des Mers d\u2019Afrique, Paris, 1803. L\u2019Homme, essai zoologique sur le genre humain. Paris, 1827. Bruce, Travels to discover the Source of the Nile, Edinburgh, 1790. Buffon, Histoire Naturelle, g\u00e9n\u00e9rale et particuli\u00e8re, Paris, 1749\u2014 1804. Burchardt, Travels in Syria and the Holy Land, London, 1822. Travels in Nubia, London, 1819. jBurchett, Travels in Southern Africa, London, 1822\u20141824. Burnes, Travels into Bokhara, London, 1834. Camper, Dissertation Physique sur les Diff\u00e9rences r\u00e9elles que pr\u00e9sentent les traits du Visage chez les Hommes de diff\u00e9rensPays, de diff\u00e9rens Ages, &c., Utrecht, 1791. Catlin, North American Indians, London, 1842. Chardin, Voyages en Perse, et autre lieux de l\u2019Orient, Paris, 1811. Choris, Voyage Pittoresque autour du Monde, Paris\n* Edinburgh Monthly Journal, October 1851,\n1821\u20141822.\tClapperton $\u2022 Denham, Travels in\nNorthern & Central Africa, London, 1826. Cook, Voyages around the World, London 1784\u20141785. Crawfurd, History of the Indian Archipelago, Edinburgh, 1820. Cuvier, Le R\u00e8gne Animal distribu\u00e9 d\u2019apr\u00e8s son Organisation, Paris, 1817. M\u00e9moire sur la V\u00e9nus Hottentote; in M\u00e9m. du Mus. d\u2019Hist. Nat. tom. v. Daniell, Medical Topography of the Gulf of Guinea, London, 1849. Daubenton, M\u00e9moire sur les Diff\u00e9rences de la Situation du grand Trou occipital dans l\u2019Homme et les Animaux ; in M\u00e9m. de P Acad, des Sei. de Paris, 1764. Dr. J. Davy, An Account of the Interior of Ceylon, London, 1821. D\u2019Azara, Voyages dans l\u2019Am\u00e9rique M\u00e9ridionale, Paris, 1809. D\u00e9non, Voyage en Egypte. De Salles, Histoire G\u00e9n\u00e9rale des Races Humaines, Paris, 1849. Desmoulins, Histoire Naturelle des Races Humaines, Paris, 1826. Dieffenbach, Travels in New Zealand, London, 1843. D\u2019Orbigny, Sur les Variations que pr\u00e9sente la Couleur de la Peau chez les Races brunes (Bull, de la Soc. Ethnol. 1846). L\u2019Homme Am\u00e9ricain consid\u00e9r\u00e9 sous les Rapports physiologiques et moraux, Paris, 1840. Du Ponceau, On the American Languages, in the Transact, of the Amer. Philos. Soc. vol. i. Earle, The Eastern Seas, or Voyages, &c., in the Indian Archipelago, London, 1837. W. F. Edwards, Des Caract\u00e8res physiologiques des Races humaines, consid\u00e9r\u00e9s dans leur rapports avec l\u2019histoire, Paris, 1829. Ellis, Polynesian Researches, London, 1831. Ermann, Reise um die Erde, Berlin, 1833\u20141838. Gallatin, Various Papers on North American Ethnology in the Arch\u00e6ologia Americana, and the Transactions of the Ethnological Society of New York. Grey, Journal of Discoveries in Australia, London, 1841 ; and on the Languages of Australia, in Journal of Geogr. Soc. vqI. xv. Hales, Philology of the United States Exploring Expedition. Hawkesworth, Voyages to the Southern Hemisphere, London, 1773. Alex. Humboldt, Personal Narrative of Travels to the Equinoctial Regions of the New Continent (transi), London, 1814\u20141829. Researches concerning the Ancient Inhabitants of America (transi), London, 1815. Kosmos (transi.) London, 1846\u20141851. IV. Von Humboldt, \u00dcber die Kawisprache, Berlin, 1836\u2014 1839. King and Fitzroy, Journal of the Voyage of the Adventure and Beagle, London, 1840. Khproth, Asia Polyglotte, Sprachatlas, &c. Tableau historique, &c. du Caucase, Paris, 1827. Knox, The Races of Men, London, 1850. Lander, Journal of an Expedition to explore the Course and Termination of the Niger, London, 1832. Larrey, Remarques sur la Constitution physique des Arabes ; Comptes rendus, tom. vi. Jjatham, Man and his Migrations, London, 1851. Ethnology of the British Colonies and Dependencies, London, 1851. Lawrence, Lectures on Physiology, Zoology, and the Natural History of Man, London, 1819! Lesson, Voyage M\u00e9dical autour du Monde, Paris, 1829. Leyden, On the Languages and Literature of the Indo-Chinese Nations, in Asiatic Researches, vol. x. Marsden, History of Sumatra, London, 1811. Morton, Crania Americana, Philadelphia, 1839. Crania Egyptiaca, Philad. 1844. Midler, Der Ugrische Volkstamm. Pallas, Voyages en Russie, et dans l\u2019Asie Septentrionale (transi), Paris, 1789\u20141793. Parry, Arctic Voyages, London, 1821\u20141828. P\u00e9ron, Voyage de D\u00e9couvertes aux Terres Australes, Paris, 1807. P\u00e9rouse, Voyage round the World (transi), London, 1798. Pickering, The Races of Man and their Geographical Distribution, London, 1849. Prichard, The Eastern Origin of the Celtic Nations, London, 1831. Quetelet, Sur l\u2019Homme et le D\u00e9veloppement de ses Facult\u00e9s, Paris, 1835. Quoy et Gaimard, Partie anthropologique du Voyage de l\u2019Astrolabe, Paris, 1829 \u2014 1834. Bitter, Die Erdkunde im Verh\u00e4ltnis zur Natur und zur Geschichte der Menschen, oder allgemeine vergleichende G\u00e9ographie, Berlin, 1832. Rugendas, Voyage dans le Brezil, Paris, 1835. R\u00fcppell, Reisen in Nubien und Kordofan ; Frankfurt am Main, 1829. Sandifort, Tabulas Craniorum diversarum Nationum, Lugd,","page":1366},{"file":"p1367.txt","language":"en","ocr_en":"VEIN.\t1367\nBatav. 1838\u20141843. Sehxmhurgk, On British Guiana, &c. in the Transactions of the Philological, Ethnological, & Geographical Societies. Scouler, On the Languages of the North-West Coast of America, in the journal of Gcogr. Soc. 1842. Dr. Andrew Smith, Report of the Expedition for Exploring Central Africa from the Cape of Good Hope, Cape Town, 1836. Soemmering, Uber die K\u00f6rperlich Verschiedenheit des Negers vom Europ\u00e9ens, Mainz, 1784. Sonnini, Travels in Egypt (transi.), London, 1799. Sparrman, Voyage to the Cape of Good Hope and round the World, Perth, 1789. Spix und Martius, Reise durch Brasilien (transi.), Travels in Brazil, London, 1824. Steedman, Adventures in the Interior of Southern Africa, London, 1845. Tiedemann, Uber das Hirn des Negers, Heidelberg, 1837. Vater, Continuation of Adelung\u2019s Mithridates, Berlin, 1806 \u20141817. Vergleichungstafeln der europ\u00e4ischen Stamm-Sprachen, Berlin, 1822. Virey, Histoire Naturelle du Genre Humain, Paris, 18_24. Volney, Voyage en Syrie et en Egypte, Paris, 1787. Wilkes, Account of the United States Exploring Expedition, Boston, 1845. Winterhottom, Account of the Native Africans in the Neighbourhood of Sierra Leone London, 1803.\nW. B. Carpenter.\nVEIN (4>Ae>, Gr.; Vena, Lat.; Veine, Fr.; Blutader,Ger.', Vena, Ital.j Vena, Span.). \u2014 ln general anatomy the term vein, in the higher animals, includes four sets of blood-vessels, differing in so many respects from each other as to render.it difficult to give a general definition which shall include all under one head, either as it regards structure, course, or function : indeed, so unlike are the different sjs-tems of veins, that the only remark which can be said to apply to them all is, that they convey blood in a direction towards the heart ; in this respect, as well as in their want of uniformity of character, being directly opposed to the arteries.\nThe four systems of veins are the systemic, the portal, the pulmonary, and certain veins peculiar to foetal life \u2014 the ductus venosus and umbilical vein ; and it will be found, upon contrasting them, that they differ much from each other, considering that all enjoy the common appellation vein. Thus, the systemic veins, which correspond to the branches of the aorta, excepting those of the abdominal viscera, collect the blood from small and numerous vessels into larger and fewer in its progress towards the heart, constituting a course of circulation of a truly venous character ; while, on the other hand, that portion of the blood, which is conveyed to the abdominal viscera by the branches of the abdominal aorta, is first collected from numerous branches into one vessel \u2014 the vena porta \u2014-thus far the circulation being venous, and is then again broken up into smaller and redividing vessels, after the manner of arteries, and forming, as regards this particular, an arterial circulation, though the vessels are nevertheless veins. In both these instances the blood conveyed by the vessels in question has a similar quality, which is characteristic of veins, and is called venous ; it is blood saturated with carbon. In the two other systems of venous circulation \u2014 the pulmonary and umbilical \u2014 the current is\nvenous while the fluid is arterial, these vessels being channels by which the blood is returned to the heart after it has left the arterialising organs. Again, as regards the structure and calibre of veins, our definition is necessarily loose ; for, while veins are, in a general way, thin, less elastic, and distensible, as contrasted with arteries, they are nevertheless very varied in these particulars in different regions, and though, for the most part, the calibre of veins is greater than that of the corresponding arteries, still this is not always the case, as is found upon contrasting the area of sections of the pulmonary arteries and veins. It is therefore imj ossible to give a succinct, and, at the same time, a comprehensive definition of vein ; and the one which appears to me to be most applicable and to include the members of each venous system is this \u2014 that a vein is a blood-vessel, neither artery nor capillary, convey-ing blood in a direction towards the heart, having walls of greater tenuity and extensibility and, at the same time, less elasticity than an artery.\nThe literary history of this subject is chiefly interesting as referring to veins, in their relation to the general circulation. Until the time of Harvey\u2019s great discovery, the general physiological relationship of the veins was not understood, and the most discrepant notions were entertained.\nHippocrates, in none of his writings, draws distinction between arteries and veins. Plato, in his Tim\u00e6us, describes the veins as connected with the heart, and receiving blood from it. He regards the veins as the messengers, transmitting to the whole body the orders coming from the soul : he attributes to them the functions of sentient and motor nerves. He considers that the veins have two centres \u2014 the heart and the liver ; and he makes no distinction between them and arteries, Praxa-goras taught that the veins were blood-vessels, in contradistinction to the arteries which he considered air-vessels. Aristotle drew no distinction between arteries and veins. Hero-philus describes both arteries and veins as blood-vessels : but he expresses himself in doubt, as to whether the veins arise from the heart or the liver. Erasistraius, holding the same general doctrines as Praxagoras, further described the texture of veins very minutely, and, according to Marx, he noticed the existence of valves. Celsus and Aret\u0153us made no advance in this subject. Galen distinguished between arteries and veins \u2014 both blood-vessels i he also observed the anastomoses of each : he stated the origin of veins to be from the liver, and of the arteries from the heart, and that both were destitute of sensation. Avicenna described the veins \u201cven\u00e6 quiet\u00e6,\u201d in contradistinction to the arteries, which he styled \u201c ven\u00e6 puisantes et audaces.\u201d According to Baulinus, Avicenna described the valves of veins under the name of \u201c cel-lulceP\nThe European anatomists of the 15th, 16th and the early part of the 17th century, remained in a state of great confusion and ig-\n4 s 4","page":1367},{"file":"p1368.txt","language":"en","ocr_en":"1368\tVEIN.\nnorance, as to the bearing of the veins upon the circulating system. Vesalius endeavoured to establish the doctrine, that the vena cava takes its origin from the heart, and not the liver ; but in this he was opposed by Sylvius, Columbus, Eustachius, and Fallopius.\nWhile C\u00e6salpinus had occasional faint glimmerings of the physiology of the veins, and Fabricius, a remarkable knowledge of their anatomy, it was still left to Harvey to indicate their function and relation to the general circulation.*\nVeins are the necessary companions of arteries, and are consequently found in all animals possessing the latter vessels.\nIn the following remarks I shall, for the purpose of examining the subject more completely, divide the consideration of vein into these heads : \u2014\nI.\tStructure.\nII.\tPhysical and vital properties.\nIII.\tOrigin, course, anastomoses, plexuses, &c.\nIV.\tFunction.\nV.\tDevelopment.\nMy observations will be principally confined to the consideration of these various heads as applied to the veins of mammalia, especially the human subject. The general anatomy of this subject in invertebrate classes has not, as yet, been sufficiently examined, and does not appear to furnish many points for generalisation beyond those supplied in the mere anatomical description given of the venous system in the several invertebrate classes, in the articles specially applied to them.\nI. Structure.\u2014There is scarcely any subject in structural anatomy, which has given rise to so many varied and discrepant opinions, and so much contradictory description as the structure of veins ; the different writers upon this point having been numerous, and with scarcely any exception, each giving an account in some, and often important, respects, contrary to those who have preceded him. This circumstance may, to a certain extent, be explained by the various observers having examined different veins, in different regions, and in different animals ; and it must be remembered that all microscopical observations necessarily differ from those which are made with the scalpel and the naked eye, and are incompatible unless conjoined, compared and interpreted by the same individual ; for, as we shall presently find, structures which seem reduced by dissection to their simplest elements, are found, when submitted to the microscope, to be compound ; this is especially the case as it regards the internal tunic of veins, as displayed by coarse anatomy and the microscope respectively. All the discrepancies, however, which have occurred cannot be settled upon these grounds, and it must be\n* For more elaborate details of literary history,\nI would refer the reader to the article Circulation, and to the learned \u201c Diatribe Anatomico-physio-logica de structura et vita venarum,\u201d by Marx. See Bibliography.\ngranted fhat in some instances the writers upon this subject have rather drawn upon their imagination than depended entirely upon anatomical demonstration. These conflicting statements, however, serve to keep before us the fact that there is considerable difference of structure in veins in certain regions.\nThe early anatomists who devoted their attention to the investigation of the intimate structure of organs, applied themselves to the study of the minute texture of veins, and it was indeed one point in their structure which was greatly instrumental in leading Harvey in his discoveries of the circulation.\nConstantinus first described the structure of veins as consisting of a \u201c tunica villosa.\u201d Vesalius speaks of the membranous character of veins, and of their being composed of three sets of fibres, \u2014 a longitudinal, a circular, and an oblique. Fallopius and Bartholini deny the fibrous nature of the coats of veins, and Diemebroeck described veins as consisting of one membranous tunic, and believes the statement of the existence of three tunics to be mere imagination. Willis, Nicolai, and Blan-card describe veins as being composed of four coats or tunics. Haller denies the existence of transverse muscular fibres in the coats of veins, which had been repeatedly mentioned by other anatomists. Lieutaud states that the veins are identical in structure with the arteries, but simply attenuated. Prochaska does not admit the existence of a fibrous tunic in veins, whilst Scemmerring says it is to be found only in the larger ones. Meckel, Autenrith, and Bichat deny altogether the circular or transverse coat of veins, and Senac says that their tunics are composed simply of longitudinal fibres.\nTo these might be added a long list of diverse descriptions, which are however of more literary curiosity than anatomical value.\nVeins, in the human subject and mammalia, and I believe in vertebrata generally, are membranous cylinders, consisting of various fibrous coats, lined internally by an epithelium. The walls of veins, which are sufficiently thick to admit of coarse dissection, are with care divisible by the scalpel into three layers, an internal, middle, and external coat : but, when submitted to microscopical scrutiny, a still further analysis is made; the internal layer is found to have a compound character, and the direction of the elementary fibres of the several tunics is also shown ; the internal and external coats are seen to be longitudinal, while the middle is compound, partly circular and partly longitudinal.\nThe relation of coarse and microscopical anatomy will be best seen by the following table ;\nCoarse Dissection. Microscopical Examination.\n{Epithelium.\nFenestrated membrane. Longitudinal fibres.\nMiddle coat { Cj\u00ee'cula.r and. longitudinal (_ fibres intermixed. Muscle.\nExternal coat j Longitudinal fibres ; com-|_ pact areolar tissue.","page":1368},{"file":"p1369.txt","language":"en","ocr_en":"VEIN.\n1369\nThis may be taken as a tabular view of the typical structure of veins of larger size, and in the smaller vessels the same order of parts is represented, but with less distinctness and greater tenuity. There are certain regions, however, where the venous texture, both in quality and order, departs considerably from the typical arrangement : these will be noticed hereafter.\nIn the following observations, the several coats of the veins will be described in succession, beginning with the innermost.\nEpithelium. \u2014 It is difficult (as has been observed by Henl\u00e9),\\n all cases, to make out a distinct epithelial layer lining the vascular cavity; but, as far as my observations go, it is more constant in arteries than in veins, and the epithelium is more perfectly formed in the former than in the latter. The anatomist will frequently make search in vain for epithelium on the inner surface of veins, and, when found, a perfect epithelial cell is less common than one imperfectly formed, the nucleus existing, but the cell-wall either partially or wholly absent.\nFig. 853.\nEpithelium from the Vena Cava of a Sheep.\na, perfect epithelium ; b, common form ; c, epithelium seen edgewise ; cl, nuclei of epithelium destitute of cell-wall. (Magnified 200 diameters.)\nThe best method for examining the epithelium is by scraping the inner surface of the vessel, and placing the material removed on a slip of glass ; or by viewing the free edge of a valve under the microscope. Existing in its most perfect form the epithelium is of a diamond or rhomboidal figure, containing a nucleus, large in proportion to the cell, of a granulai character, and lenticular or oval form. The nucleus is distinct and well defined. The cell itself is clear, pale, and watery to an extent that it is impossible to portray in a wood-cut. Henl\u00e9 states that the long axis of the rhomboid corresponds with that of the vessel in which it exists. In the figure { fig. 853.a), is represented the most perfectly formed specimen I have seen from a vein ; the rhomboidal figure being very marked : it was obtained from the vena cava of a sheep. There is also seen (fig. 853. 5), a more common form, where the\ncell and nucleus are both present, but the structure is less regular and more confused. The epithelium is of the pavement or scaly form, existing in a single layer : the cells are flat, and either have no cavity, the opposed sides being adherent, or the cavity is very minute. This is displayed in the drawing {fig. 853. c), where some cells are seen edgewise : in this position the dimensions of the nucleus are observed to bulge out the cell-walls where it is placed, while the cell itself forms a comparatively narrow line, or is even reduced in appearance to a mere linear filament attached to the nucleus, sometimes at one extremity and sometimes at both.\nBut the condition in which I have most commonly found the epithelium is that represented at d in the accompanying figure ; the nucleus, the essential part of the cell, being apparently all that is present, and representing the whole epithelial structure. These lenticular corpuscles, the nuclei, are scattered on the inner surface of the vein in pretty much the same position and form as if the cells were present, but the cell-walls are not sketched out, or the nuclei are only here and there partially invested by a cell. This appearance I have observed in the freshest specimens, and it may also be produced by keeping those where the cell is distinct for a short time, when the cell-wall liquefies, and becomes invisible. From the fact that the nuclei are in some instances pretty equally separated from each other, and hold about the same relative distances, whether the cell-wall be present or not, it would seem not improbable that, where not visible, the cell might still exist in a state of imperfect and indistinct formation,\u2014that the blastema may be present in a mucilaginous condition, but of sufficient density to retain the nuclei in their proper relative position.\nThe nuclei may sometimes be seen thus arranged on the surface of a valve near its clear, thin edge, as is seen with unusual distinctness in fig. 865. a. These appearances are generally destroyed by manipulation. When a valve is placed for examination, the nuclei are apt to float off its surface in the fluid with which the object is moistened, and arrange themselves along the free margin of the valve in the interval between its edge and the glasses.\nHenl\u00e9 has represented, in his matchless work on general anatomy, the edge of a valve magnified, in which the nuclei of epithelium are arranged on a clear area, which rims the margin of the valve ; and this transparent, structureless boundary he describes as the epithelial cells, in which the nuclei, also visible, are embedded. I have seen well developed epithelium at the edge of a valve, but it did not present the appearance depicted by Henl\u00e9, the cell being a mere line as represented in fig. 865. A. a, and scarcely forming a transparent edge. I have also occasionally seen a structureless rim to a valve, and as that was not changed by the washing and brushing off' of the superimposed epithelium,","page":1369},{"file":"p1370.txt","language":"en","ocr_en":"3370\nVEIN.\nI have given it a different interpretation: I have indeed considered it as a reduplication of the fenestrated membrane, existing there in a state of great tenuity and destitute of fibrous striations.\nFrom the vena cava of the human subject I have obtained epithelium, differing far from the normal form. The specimen consisted of flat, irregular cells, with a small bright nucleus ; some cells distinct, others pale and ill defined ; some densely granular, others scarcely so at all.\nIn Birds (Loon \u2014 Colymbus septentrionalis), I have seen the epithelium diamond-shaped, with a large, flat, bright nucleus.\nIn Batracliia (Frog \u2014 Rana temporaria), the epithelium was large, pale, and irregular.\nIn Fish (Cod \u2014 Gadus morrhua) the epithelium was large, irregular, and granular.\nFenestrated membrane. \u2014 This structure, which Henl\u00e9 has called the \u201c fenestrated,\u201d or \u201c striated \u201d membrane, is placed intermediately between the epithelium and the fibro-vascular elements of the vessels\u2019 walls, and, from this circumstance, as well as its physical properties, it bears a strong resemblance to the basement or limitary membranes on the skin, the serous and mucous surfaces.\nThis structure has been described and figured by Henl\u00e9, in a manner which exactly coincides with my own observations. When a portion of the membrane is stripped off the inner surface of a vein (or artery, for it is the same in either), and examined under the microscope, it is found to consist of a thin, continuous sheet, of a pellucid, structureless membrane, to which are adherent some reticulated fibres, having a longitudinal direction \u2014 hence it is \u201cstriated.\u201d It is also frequently perforated with small holes, from which circumstance it is called \u201c fenestrated.\u201d This homogeneous membrane has the remarkable property of rolling itself up in the form of a scroll, somewhat like the elastic laminae of the cornea. According to Henl\u00e9, it rolls itself in the longitudinal direction, but I have found the same tendency in the opposite course. The apertures, or fenestr\u00e6, seen on the membrane, all have more or less of a circular or oval form, and I have found that the number and extent of these perforations depend on the manipulation it has undergone. Its physical properties are peculiar ; it is crisp and somewhat elastic, and its inclination to roll up in a scroll is so great, that it is never seen in a flat form. The elasticity, which it possesses, is the reason, as it seems to me, why the fenestr\u00e6 are universally of a rounded form ; for when any lesion is effected in it, retraction occurs all round from the injury, and thus makes the point or line of lesion the axis of a circular or oval aperture, as the case may be. In several specimens of this tissue, in which no fenestr\u00e6 at first existed, I have produced them to any extent by pricking or lacerating it with needles. The fenestr\u00e6 in the figure were thus produced.\nThe longitudinal striations appear to me to be some fibres of the next tunic, \u2014 the in-\nternal longitudinal fibrous coat \u2014 accidentally adherent to the homogeneous membrane.*\nFig. 854.\nFenestrated or Striated Membrane from the Jugular Vein of the Red-throated Diver (Colymbus septentrionalis).\na, Fenestr\u00e6. (Magnified about 100 diameters.)\nIn the accompanying drawing (fig. 854.) is represented a portion of this membrane, from the jugular vein of the red-throated diver (Colymhus septentrionalis). It was of a pale pink tint, from contact with the blood in the vessel, and, seen by transmitted light in the microscope, had a slight yellow cast. It was marked by fine longitudinal threads on one surface, which projected at some spots beyond the torn edge of the membrane.\nPurkinje and Rauschel consider this membrane as similar to the middle coat of arteries. Valentin describes it as a peculiar structureless membrane. Henl\u00e9 considers it as a transition from epithelium to fibrous tissue, in which opinion he is supported by Schwann.\nThe fenestrated membrane has been found on various parts of the internal surface of the arteries and veins; but the best specimens I have seen have been from the principal veins of large birds (goose, loon, gull), &c. At the\n* Henl\u00e9 has made a singular speculation concerning the nature of this structure : he believes it to be an intermediate stage between the epithelium and the longitudinal fibres next beneath it \u2014 that the former is converted into the latter, and that this is its intermediate condition. He believes that the epithelium becomes fused into a continuous sheet, and the nuclei absorbed, and that this subsequently breaks up into fibres, \u2014 in short, that fibrous tissue is formed from epithelium, and that the coats of the vessels derive their density and increase from the epithelial cells secreted on their interior.","page":1370},{"file":"p1371.txt","language":"en","ocr_en":"VEIN.\t1371\nfree margin of valves I have occasionally seen, as noticed above, a clear, structureless rim, which I have imagined to be this membrane reduplicated, the membrane being extremely thin, and the interposd fibrous lamina not reaching quite to the margin.\nIt is said by Henl\u00e9 and others only to exist in a few places, and certainly it is not always to be found, though it is not perhaps right to limit its existence to those spots only where it has been recognised, as its extreme tenuity and firm adhesion to the next coat might account for its not being generally seen.*\nThe tissue in question is best seen by slitting up a vein and pinning; it out on cork. The inner surface is then scratched with a needle after it has been moistened. The fenestrated membrane retracts, and its edges may be ruffled up and a small portion removed by the points of very fine forceps, and thus obtained for examination, which is best done without any superimposed glass, as that flattens the coils and folds, and it is impossible to unravel them.\nFig. 855.\nTransverse vertical Section of the Wall of the Subclavian Vein of an Ox, exhibiting the relative Thickness of the Three Coats.\na, internal coat ; b, middle coat ; c, the entire external coat. (Magnified 40 diameters.)\nInternal tunic of longitudinal fibres. \u2014 The internal tunic of longitudinal fibres is extremely thin, and occupies but a very small amount of the thickness of the vessels\u2019 walls. This is well seen in fig.855.a, which is a transverse section of the subclavian vein of,an ox, made vertical to the surface, and displaying\n* It appears to me that there are sufficient grounds to acknowledge the existence of a limitary membrane beneath the epithelium in the bloodvessels, and no sufficient reason to question its universal distribution. It must be recollected that there are certain regions, even in the mucous membrane (the nasal fossa, for instance), where no basement membrane has been found, and I am not aware that, in the skin, it has ever been separated from the chorion, and yet in neither case is its existence doubted. To exhibit the limitary membrane well, some peculiar mechanical arrangements of the surface is necessary, as papillae or crypts, and such are not presented on the surface of blood-vessels. It is not to be wondered at, therefore, that there is here great difficulty in displaying the limitary membrane.\nthe relative thickness of the three elementary fibrous coats.\nSpecimens for displacing the profile views of the walls of veins are best obtained by slitting up the vessel, pinning it out upon cork, and suffering it to get dry. Sections are then to be made vertical to the surface, either parallel to, or at right angles with, the axis of the vessel. Thin shavings may then be removed with a very flat knife (and for this purpose, a Beer\u2019s cornea knife is the best), and when placed on a slip of glass, moistened, and covered with a square of thin glass, are ready for observation. The accompanying drawings were made from sections thus obtained.\nWhen a longitudinal section of the internal tunic is examined with a high power, as in fig. 856. a, it is seen to consist of very fine yellow elastic tissue, which is peculiarly pale and indistinct, having mainly a longitudinal direction, but being much interlaced and matted together, so that its longitudinal course is, in many situations, obscure. This coat is seen to be fine, and dense, and in strong contrast to all the other structures, from which it is separated by a distinct line of demarcation. When thus viewed, the fibres of this tunic are seen to present a succession of waves, not unlike those of white fibrous tissue, but finer and smaller : whether these undulations are from its own inherent pro-\nFig. 856.\nLongitudinal vertical Section of Wall of Subclavian Vein of an Ox.\na, internal coat rather thicker than common ; b, middle coat ; c, part of external coat. (Magnified 200 diameters.)\nperties, or whether they are produced by its adhesion to the next tunic, whose elastic contraction is greater than its own, thus throwing it into folds and waves, I am unable to say. The identity of these fibres with yellow elastic tissue is shown by the action of acetic acid, which does not destroy them, but renders them even more distinct, while the contiguous","page":1371},{"file":"p1372.txt","language":"en","ocr_en":"1372\tVEIN.\nmasses of white fibrous tissue are obliterated, former gradually diminish, and the latter, in When treated with this reagent the fibres of the same proportion, increase, as viewed fur-this coat lose their wavy character to a cer- ther and further from the inner surface; and tain extent, and present intersecting undula- that point where the discs entirely disappear tions. (Fig. 857. a.) When the internal coat and the longitudinal fibres alone remain may is seen in transverse section, it presents a be considered as the external limit of the\ngranular, indistinct appearance, without fibres of any determinate direction : in some places it presents lines of a crumpled or corrugated aspect. In Jig. 858.a, this may be seen, as also its distinctness from the next coat, from which it is separated at one part by a slight interval.\nThis coat appears to exist in all the veins, and in the smaller ones, and larger capillaries when treated with acetic acid, as hereafter to be described, its presence would seem to be indicated by the internal longitudinal nuclei, which are then displayed.\nMiddle coat, of intermixed circular and longitudinal fibres. \u2014 This tunic occupies about one-fourth of the entire thickness of the wall of a vein. Its internal boundary is sharp and distinct, where this coat is in contact with the internal, but the outer boundary, where it gradually merges into the external, is indefinite, and indeed artificial.\nIn fig. 856. the middle coat is represented at b, and is composed of intermixed fibres of longitudinal and transverse yellow elastic tissue embedded in a nidus of white fibre. As this figure represents a longitudinal section, the transverse fibres of the yellow element\nFig. 857.\n\nLongitudinal vertical Section of Wall of Subclavian Vein of Ox, treated with Acetic Acid.\na, internal coat ; b, middle coat ; c, part of external coat. (Magnified 200 diameters.)\nare seen cut across, and appear as small discs : on the other hand, the longitudinal fibres with which they are mingled, are seen in profile, as interlacing and parallel rods : the\nmiddle coat. This limit is very clearly seen in a specimen treated with acetic acid (fig. 857. b ) ; when, as in fig. 858. b, the section has been transverse, the discs and rods of yellow elastic tissue occupy a position and proportion the reverse of what has been described. The discs are the most abundant on the outer, and the rods on the inner part of this coat, the former being seen in section, and the latter in profile.\nThis middle coat is verj^ compact, especially near the inner surface, and it gradually becomes less so in proceeding outwards.\nIt is difficult to tell what is the course and direction of the nidus of white fibrous tissue in which the yellow element is embedded, as in the middle coat it forms a dense granular compact mass*, when seen in situ, and its true nature is only displayed by the action of acetic acid. When, however, portions of the tissue are picked abroad with needles, though its direction is lost, its characters are obvious.\nAs it regards the muscularity of this coat, there can exist no doubt. The recent observations of K\u00f6lliker on the low form of muscle, which he designates \u201c muscular,\u201d or \u201c contractile fibre-cells,\u201d have placed this previously obscure subject in an intelligible and satisfactory light, and have done much to explode the idea of non-muscular contraction, by exhibiting the wide diffusion of this hitherto 'unrecognised tissue.\nK\u00f6lliker describes two forms of fibre-cells as existing in blood-vessels, \u2014 one, consisting of short, round, spindle-shaped, or rectangular plates, like epithelium ; the other, of long plates of irregular, rectangular, spindle, or club, shape. The substance of these cells is soft, light yellow, and homogeneous, and each contains a peculiar, characteristic nucleus, whose shape is constant, being that of a club or staff. These fibre-cells are placed transversely as it regards the vessel, and constitute a thin coat, immediately external to the lining membrane, intermixed with cellular tissue. These muscular elements are clearly seen (as exhibited by their nuclei) by the action of acetic acid on small vessels. (Fig. 860.)\nHe further states that the great development of the uterine veins during pregnancy is principally from an increased size of the fibre-cells existing in the middle coat, but partlv also from the inner and outer coat acquiring a considerable quantity of smooth muscular fibre. According to the same authority this muscular element is not found in the veins of the uterine portion of the placenta, the cerebral\n1t I would here observe, that when white fibrous tissue is dried and re-moistened, as in these sections, it does not regain all its physical characters : it has lost to a great degree its wavy lines, and hence it is not so easily recognized.","page":1372},{"file":"p1373.txt","language":"en","ocr_en":"VEIN.\n1373\nveins, the cerebral sinuses, Breschet\u2019s veins of the bones, and the venous cells of the corpora cavernosa.\nExternal coat of longitudinal fibres.\u2014The external coat consists of a mass of areolar tissue, adhering together with more or less compactness, and running in a longitudinal direction.\nThis tunic occupies full two-thirds of the entire thickness of the whole wall of a vein. Its internal boundary is irregular at the union with the equally irregular outer limit of the middle coat, and its external boundary is the\nFig. 858.\n\nTransverse vertical Section of Subclavian Vein\nof Ox.\na, internal coat ; b, middle coat ; c, part of external coat. (Magnified 200 diameters.)\nloose cellular tissue into which it degenerates, and which constitutes the \u201csheath\u201d of the vessel. This coat, like the preceding, gradually diminishes in density and compactness as it is examined further and further from its inner limit, though its density is everywhere inferior to that of the middle ; indeed, it may be said that the tissue of which the vessel is composed becomes looser and looser in proceeding outwards from the inner boundary of the middle coat, \u2014 this quality passing gradually from one coat to the other.\nThe textural arrangement of this tunic must be examined, like the preceding, from longitudinal and transverse sections. In the former it is seen that bundles of rods of yellow elastic tissue are disposed in alternate laminae with white fibre, or rather, that the former are embedded in a mass of the latter, and that they are a continuation of the longitudinal fibres of the middle coat, which gradually become arranged more and more in strata, and at increasing distances. (Fig. 856. c.)\nThe characters of the white fibrous tissue between the bundles of yellow, become more conspicuous as the laminae are wider apart.\nThe stratified arrangement of the fibres, and their correspondence with the longitudinal rods of the middle coat are very well seen in the specimen treated with acetic (fig- 857.).\nWhen this tunic is viewed in transverse section, the relative thickness and proportion of the lamellae are better seen than in a longitudinal cut : the yellow element is seen to occupy but a small relative thickness in comparison with the white.\nWhen viewed with a high magnifying power the divided extremities of the rods of yellow fibrous tissue form undulating, and somewhat imbricated lines of discs, while the white fibrous tissue, cut across, shows slight, indistinct, wavy indications. (Fig. 858. c.)\nSeen with a low power, the ends of the yellow fibrous tissue appear as series of dark undulating dots on a field of white.\nMinute veins. \u2014 When very small veins, a few removes from capillaries, are examined microscopically, they merely present faint striations in the longitudinal direction. When, however, these vessels are treated with acetic acid, nuclei and fibres are distinctly displayed, whose long axis may be assumed to indicate the direction of the tunic (or set of fibres) which they represent, in which they are embedded, and of which they form a part.\nHenl\u00e9 was, I believe, the first to point out this mode of textural dissection of vessels, and nothing can be more satisfactory than the analysis that it makes. By this means small vessels alone can be examined, but the scrutiny may be carried up to those the third of a line in diameter, which are sufficiently transparent, when entire, to exhibit the nuclei. Small vessels may be conveniently obtained from the pia mater and mesentery ; they are there free from other structures, and their form is not interfered with.\nI have found, however, that it is in the pia-mater somewhat difficult to trace the small veins ; the arteries about them are more definite and conspicuous, and less injured by manipulation, and generally catch the attention of the observer. It has been more convenient to obtain isolated cerebral veins from the surface of the ventricles of the brain ; the small veins on the corpus striatum may be raised and torn away with the points of fine forceps, and sufficient capillaries will generally be found attached to their extremities to exhibit the structure of these vessels of all sizes. The accompanying figures were made from specimens thus obtained, about whose venous character there could be no mistake.\nSmall veins vary in structure in different regions, and according to their size ; some ap-approach the structure of arteries *, whilst\n* It may be convenient here to give a brief outline of the anatomy of capillary, and minute, arteries. Their structure is more definite than that of veins ; their walls are thicker and their cavity less in proportion. The larger ones exhibit both a longitudinal and a transverse striation. When treated with acetic acid the nuclear corpuscles are numerous, sharply defined, and obvious in their direction.\nCapillaries, up to about l-1600th of an inch in","page":1373},{"file":"p1374.txt","language":"en","ocr_en":"1374-\nVEIN.\nothers are far removed from them in composition.\nVenous capillaries do not, that I am aware of, differ from arterial. They consist of tubes of homogeneous membrane, studded here and there with nuclei of a more or less oval form, and placed generally with their long axis corresponding with that of the vessel. In passing to larger veins the change in structure of the vessel (its increase and character) depends upon the region from which it is obtained, and whether or not it is endowed with muscle-cells.\nIn the cerebral veins, which have no muscle, in passing from small capillaries to larger vessels, all that is observed is the superaddition of a tunic of areolar tissue, surrounding the lining membrane ; and when this tissue is treated with acetic acid, all that is observable is a series of nuclei, oval, irregular, and longitudinal, embedded in the substance of the parietes, which have a perfect resemblance to the external, or cellular coat of small arteries. (Fig. 859. a.) In none of the microscopical cerebral veins have I been able to discover any nuclear or yellow fibres. In veins of the to Ti_ of an inch the vascular wall has been composed of a tissue rendered transparent by acetic acid, and displaying oval and irregular nuclei having a longitudinal course, without any admixture of elastic fibre. The most internal of the nuclei appeared elongated, but there was no appearance of fibres upon the internal membrane, so as to produce a striated membrane.\nIn those veins which are endowed with\ndiameter, consist of tubes of homogeneous membrane, studded here and there with nuclei of an oval form, whose long axis is that of the vessel, except in the larger ones, where a few are placed transversely. These corpuscles are elongated, and more numerous, in the larger capillaries.\nIn arteries about 1-600th of an inch, the walls consist of a homogeneous tube, with the nuclei on the outer surface still more elongated ; and external to this, a set of nuclei, club-shaped and sharply defined, placed at right angles to the former, and representing the circular (muscular) tunic in which they are embedded.\nIn larger arteries a cellular tissue, still more external, is seen, whose corpuscles\u2014oval and irregular\u2014 are longitudinal. In such arteries (say, about 1-300th of an inch in diameter), the tunics are, 1st. a homogeneous tube covered with elongated longitudinal nuclei; 2nd. a circular tunic, represented by the club-shaped transverse nuclei ; and 3rd. a longitudinal tunic of cellular tissue, in which are imbedded oval and irregular nuclei. In passing to larger vessels, the nuclei of the internal coat elongate and disappear ; and the internal membrane then consists of perfect striated membrane, the homogeneous tube being covered with very fine longitudinal fibres of elastic tissue. Such may be seen in arteries of l-100th to l-60th of an inch in diameter, and in some much smaller. Fibres make their appearance shortly afterwards in the circular tunic, intermixed with the club-shaped nuclei.\nThe proportion existing between the diameter of an artery and the thickness of its walls is subject to considerable variety ; and the same may be said of the relative thickness of the several tunics which compose the wall.\nHenl\u00e9 has given good figures of the structure of arteries.\nmuscular tissue, small club-shaped nuclei are observed placed externally to the lining mem*\nFig. 859.\nA,\tMinute Cerebral Vein (about l-200th of an inch diameter), from Sheep, treated with Acetic Acid.\na, wall ; b, cavity.\nB,\tVenous Capillaries (a, about l-1600</t of an inch b, about t-OOOth of an inch) treated with Acetic Acid.\nIn both these figures persistent nuclei of areolar tissue and epithelial nuclei are alone visible. (Magnified 200 diameters.)\nbrane, and transversely as it regards the vessel ; these show themselves very distinctly on the addition of acetic acid, and are characteristic of the \u201c muscular fibre-cells\u201d of K\u00f6lliker. Such may be seen in the small veins of the mesentery, which are more easily examined than any other veins of this class. In these vessels, two or three removes from capillaries, the muscular nuclei make their appearance, at first, few in number and irregular ; and in still larger, but microscopical veins, these nuclei are seen to be mixed up with, or covered in by, more or less areolar tissue* which at first is destitute of nuclear fibre, but contains conspicuous nuclei, oval and irregular in shape and longitudinal in direction. In the accompanying drawing (fig. 860. b) is a small vein from the mesentery of a rabbit, measuring about of an inch in diameter, and treated with acetic acid. On the lining membrane are seen a few elongated nuclei and longitudinal striations, constituting a sort of incipient striated membrane. External to this is a thin layer of muscular tissue, and without that, again, is cellular tissue, which constitutes the main bulk of the vascular wall. The muscular coat is less distinct than in arteries of the same size and thinner in proportion to the areolar coat.\nSuch veins have, however, a strong resemblance to small arteries. Henl\u00e9 states that the two systems of vessels are not to be distinguished in those measuring up to of an inch ; and he appears to consider thinness of wall as the main characteristic in larger microscopical veins. He instances one vessel, which he considers as venous, measuring of an inch in entire diameter, having an annu'ar tunic 3^-, and a cellular -j-g^ of an inch. It has appeared to me that the differences of these vessels are principally these, \u2014 microscopical veins have thinner walls ; the mus-","page":1374},{"file":"p1375.txt","language":"en","ocr_en":"VEIN.\neular tunic is less distinct, thinner than the areolar, with which it is more or less mixed up, and the latter is more abundant and more developed than in small arteries.\nIn passing to vessels of larger size, the fibrous tissue is seen to have a more conspicuous development. The longitudinal stri-\njFig. 860.\nA, Small Portion of the Margin of a compressed specimen of the Penal Vein of a Rabbit, treated with Acetic Acid.\na, external longitudinal coat, exhibiting yellow fibres and persistent nuclei of areolar tissue ; b, middle circular tunic, showing nuclei of muscle cells ; c, internal longitudinal coat (striated membrane), the limit of the vessel\u2019s cavity ; d, corresponds to a small portion of the cavity of the vein.\nB, Minute Vein from Mesentery of Rabbit, exhibit-ng the three Tunics less distinctly. (Magnified 200 diameters.)\nations and fibres on the lining membrane form a perfect striated membrane, and, in still larger vessels, increase so as to constitute a compact coat of fibres, of more or less density \u2014 the internal tunic of longitudinal fibres. In the middle coat, the muscular element becomes involved and mixed up with areolar tissue, some fibres of which run parallel, and some at right angles to the muscular nuclei. The external tunic of areolar tissue becomes increasingly developed, and yellow fibrous tissue conspicuous and abundant.*\nIn fig. 860. a, is represented part of the renal vein of a rabbit. The vessel is not cut open or seen in section, but is simply laid upon glass, treated with acetic acid, and a small portion of the margin submitted to microscopical scrutiny. The internal membrane is densely striated, and the other coats developed in proportion.\n* In the comparative examination of small and large blood vessels, there is much to confirm Ilenle\u2019s doctrine of nuclear and cell fibre. In the capillaries, which are mere tubular cells, there is no fibre, and the nucleus is persistent ; in larger vessels, where fibrous tissue is developed, the nucleus disappears and yellow fibre is found : but in those veins which retain abundant persistent nuclei, as the cerebral veins, even in those of larger size, no nuclear fibre is detected.\n1375\nThere are certain regions in which the veins undergo striking modifications in structure, which require description ; and the remarkable organs\u2014valves\u2014placed in their interior are yet to be considered.\nThese points will be examined as follows : \u2014\nI.\tVeins, at their junction with the heart.\nII.\tCav\u00e6, passing through the diaphragm and pericardium.\nIII.\tCerebral sinuses.\nIV.\tUmbilical vein.\nV.\tVenous valves.\nI. At the junction of the veins with the heart there is a gre=it alteration in their composition, and this as it respects both cav\u00e6, and the pul-monart/ veins : they assume a muscular character, and become thicker and red, which arises from a prolongation of the muscle of the auricle into the fibrous structure of the vein.\nThis anatomical fact, as far as the cav\u00e6 are concerned, was described as early as 1664, by Borelli ; subsequently (1700), by Bidloo, who gave figures of it ; and afterwards (1779), by Gorter, who imagined that the muscle was continued into the smaller vessels, and that it there assumed a paler colour.\nThis muscular layer (though its existence is denied by Cruveilhier) may be followed upon the superior vena cava as far as the clavicle, upon the inferior as far as the diaphragm, and upon the pulmonary veins as far as the division of the trunks into branches. (Henl\u00e9.) It exists on the superior cava in greater amount than on the inferior, and it is there best submitted to examination. When viewed with the naked eye, the vena cava superior, at its junction with the heart, is seen to be red and muscular, and thicker than elsewhere. In following this away from the heart, the muscular character gradually diminishes, and the ordinary fibrous tissue assumes the preponderance till the former is altogether lost. At ten lines from the junction of the vessel with the heart the mass was removed from which the accompanying drawing was taken.\nThe cav\u00e6 of some birds are sufficiently thin and transparent to be viewed with transmitted light when entire, and when slit up and held to the light a beautiful arrangement of these fibres is seen : they do not form one fiat, even, circular, covering, but are arranged in numerous, successive, interrupted, rings, very fine and red, gradually diminishing as they are seen further from the heart. I have observed this in the red-throated diver (Colymbus sep-tentrionalis), moor-hen (Gallinula chloropus), and various other birds. According to Cuvier, in the ostrich, muscular fibres extend the whole length of the posterior cava, and disappear sudderfty opposite the kidneys.\nWhen a little mass of this structure is examined with the microscope, it is found to consist of muscle of the same character as that of the heart, \u2014 the fibres being small, striped (though, perhaps, rather less distinctly so than that of the auricle or ventricle), and, as far as I have seen, destitute of sarcolemma. There is a good deal of wavy fibrous tissue, intermixed with the muscle ; in this respect, con-","page":1375},{"file":"p1376.txt","language":"en","ocr_en":"1376\tVEIN.\ntrasting remarkably with that of the heart : this exists in less amount in the immediate vicinity of that organ.\nThere is yet another peculiarity in the structure of the great veins near the heart,\u2014 they have a partial investment of the serous layer of the pericardium ; this, however, exists only on the anterior surface ; and in the inferior cava the amount of serous covering is very small.\nFig. 861.\nA Mass of Muscular Fibres from the Middle Coat of the Superior Vena Cava of the Human Subject, eight or ten lines above its junction with the Auricle. (Magnified 200 diameters.)\nIT. When the cavce pass through the pericardium and diaphragm they contract an intimate connection with those structures whose fibrous tissue is more or less reflected upon them and adds to their coats. Upon the superior cava are to be seen (external to the pericardium) white, glistening fibres, having a longitudinal course, and traceable from the pericardium directly upon the vein. The pulmonary veins have a similar covering.\nIn the human subject, the inferior cava passes through the pericardium and diaphragm at once, and there forms so intimate an adhesion to the margin of the aperture that I have removed striped muscle* (of the diaphragm) from the fibrous tissue of the vessel, it having taken its origin from the outer tunic of the vein.\nIn many of the lower animals (as in the sheep, cat, and rabbit,) there is a considerable interval between the diaphragm and pericardium, in which the vena cava inferior is invested with a covering of fibrous tissue contributed from both these sources. It is white,\nglistening, and strictly longitudinal, and is furnished in largest amount by the pericardium.\nIII.\tCerebral sinuses.\u2014The cerebral sinuses hold the place of large veins to the brain, but are materially different from large veins in structure. They consist of excavations or (tubes in the substance of the dura mater,\u2014 the dura mater is, as it were, split into two layers, and the interval is the cavity of the sinus. Their form, which is very irregular\u2014 triangular, quadrilateral, &c.\u2014differs in different situations.\nThe internal or lining membrane of the sinuses is stated by all anatomists to be identical with that of the veins ; but its exact amount and nature I have not myself ascertained. The continuity of the lining membrane with that of the veins is seen where the sinuses join the veins ; thus, at the cavernous sinus, where the ophthalmic vein and circular sinus join it, the lining membrane adheres to the inner wall of the sinus, but is separated from the outer by the carotid artery and certain nerves. The other element of the walls of these peculiar veins is the white fibrous tissue of the dura mater, arranged without any regularity. The inner surface of these vessels is smooth, but rendered extremely irregular by the occurrence of numerous fibroqs processes on bands projecting into their cavity. In the superior longitudinal sinus, the cavernous, and middle basilar, this is most conspicuous. In the first mentioned of these, the fibrous bands have been called \u201c cord\u00e6 Willisian\u00e6 \u201d (after Willis, their first describer). They are slips of white fibrous tissue passing from the sides of the sinus, especially near the angles, attached at both extremities, and either free or attached along one side : these give the appearance as if the inner surface were divided into cells ; into some of these the probe enters and passes on into the veins on the surface of the brain ; others are blind, or lead to lesser sinuses, which not un-frequently run parallel, for some length, to the great sinus ; or the probe passes from one of these cells to another. In. the cavernous sinus these fibrous bands are so numerous that they look like a mass of areolar tissue, whose areolae are distended with blood. The cord\u00e6 Willisian\u00e6 are traversed by minute arteries. (Sir C. Belli)\nIV.\tThe umbilical vein has a structure quite peculiar to itself. The vessel may be best examined by splitting it up with a director and pinning it down on cork, with its inner surface upwards. It is then seen to be smooth, valveless, and whiter than other veins.\nFrom the inner surface I have obtained epithelium : the cells were flat, irregular in outline, granular and fatty.\nOn making an incision, the membrane of which it is composed retracts, so as to leave a gap, and displays the dense fibrous mass which forms the basis of the cord. It tears off in irregular shreds, not showing a tendency to tear in any particular direction. With care, considerable portions of the membrane may be stripped off. This structure is soft, elastic,","page":1376},{"file":"p1377.txt","language":"en","ocr_en":"VEIN.\n1377\nand semi-pellucid. It appears structureless to the naked eye, and looks almost like a thin film of fecula jelly (arrow-root made with water), or rather, perhaps, like the flaccid dull cornea of an animal dead some days. When separated, it coils up, and, where the surfaces have become adherent, it is difficult to unfold it again : it now looks and feels like thick mucus\u2014it is semitransparent and adhesive. When seen under the microscope, it is found to be indistinctly fibrous ; some masses appear as a dense web of flat fibres, the fibres being strictly on the same plane, with their sides adherent at some points, and leaving intervals at others ; in some places the interspaces are only small specks on the surface of what appears to be in other respects, an almost homogeneous sheet ; there are also some indistinct longitudinal striations, connecting these minute interspaces and obscurely indicating the outline of fibres. The element of which this coat is composed is singularly pellucid under the microscope, scarcely refracting excepting at its edges.\nThe fibrous mass of which the vein is composed, in many places exhibits the appearance as if the fibres were formed of spindle-shaped cells strung together, with their ends overlapping ; and these cells may be occasionally isolated, \u2014 they are spindle-shaped and have an oval nucleus. They resemble those obtained from the middle coat of the aorta of a foetal pig, by Lehmann. (See his figure.)\nWhether this condition is the result of imperfect maturation of the tissue of which the vein is composed, or otherwise, I am unable to say.\nV. Valves. \u2014 The valves are membranous folds on the inner surface of the veins, having a definite form and regular arrangement with regard to their object\u2014the progress of the venous blood to the heart, and obstruction to its regurgitation. They are of peculiar interest to the physiologist, as presenting a clear and elegant specimen of animal mechanics ; and to the literary anatomist they are not less interesting, as having been one of the main objects which suggested to Harvey his brilliant deduction of the circulation of the blood.\nCruveilhier states that the valves of veins were first discovered by Etienne. Harvey leaves the priority of discovery in doubt; for he writes, \u201c The celebrated Hieronymus Fa-bricius of Aquapendente, a most skilful anatomist and venerable old man ; or, as the learned Riolan will have it, Jacobus Sylvius, first gave representations of valves in the veins.\u201d* Fabricius himself lays claim to the discovery, \u201cnon solum nulla prorsus mentio de ipsis facta sit, sed neque aliquis prius h\u00e6c viderit, quam anno Domini septuagesimo quarto, supra millesimum et quingentesimnm, quo \u00e0 me summa cum laetitia inter disse-candum observata fu\u00eare.\u201df Marx, who ap-\n* Harvey on the Motion of the Heart and Blood, Sydenham Society\u2019s Translation, chap. xiii.\nf Fabricius, ab Aquapendente. Opera omnia Ana-tomica, &c. Lips. 1687, p. 150. Fabricius calls the valves by the felicitous term, \u201c osteola,\u201d little doors.\nVOL. IV.\npears to be profoundly versed in the literature of this subject, says the discovery is due to Erasistratus ; for he observes, \u201c Erasistratus (304 B.c.), item clarus anatomus jam subtilius in structuram et usum venarum inquisivit, valvulas jam observavit.\u201d*\nHarvey\u2019s description of the valves is so apposite and clear, as well as so interesting in a literary point of view, that I shall quote it. The valves, he observes, \u201c consist of raised or loose portions of the inner membrane of these vessels, of extreme delicacy, and a sigmoid or semilunar shape. They are situated at different distances from one another, and diversely in different individuals ; they are connate at the sides of the veins ; they are directed upwards or towards the trunks of the veins; the two\u2014for there are, for the most part, two together \u2014 regard each other, mutually touch, and are so ready to come into contact by their edges, that if any thing at-\nFig. 862.\nVenous Valves, after Fabricius. f\na, femoral vein ; b, saphena interna.\ntempt to pass from the trunks into the branches of the veins, or from the greater veins into less, they completely prevent it; they are further so arranged, that the horns of those that succeed are opposite the middle of the convexity of those that precede, and so on, alternately.\u201d He further writes, \u201c In many places two valves are so placed and fitted, that, when raised, they come exactly together\n* Marx. Diatribe Anatomico-physiologica de Structura atque Yita Yenarum. Carls. 1819, p. 6. f Fabricius, Opera omnia, tab. iv. p. 157.\n4 T","page":1377},{"file":"p1378.txt","language":"en","ocr_en":"1378\nVEIN.\nin the middle of the vein, and are there united by the contact of their margins ; and so accurate is the adaptation, that neither by the eye, nor by any other means, can the slightest chink along the line of contact be perceived. But if the probe be now introduced from the extreme towards the more central parts, the valves, like the flood-gates of a river, give way, and are most readily pushed aside.\u201d*\nValves exist in two different situations ; namely, at the orifices of lesser veins where they join the trunks which they supply, and in the canals of veins, arranged at various points.\nDiagram exhibiting different forms of Valves.\na, valve placed at the orifice of the renal vein in the sheep, seen in face ; a', the same in ideal section ; b, the ordinary semilunar valve from the tube of a vein ; V, the same in section ; c, imperfect valve at orifice of intercostal vein ; c', section of imperfect valve at orifice of hepatic vein ; d, the same in face (the dotted lines in a, c and dcorrespond to the . orifices of the respective veins) ; e, very imperfect valve ; d, the same in section ; /, plan of double valve at orifice of vein ; /', the same in section ; g, ideal section of small valve and sinus ; h, section of sinus without a valve.\nAt the orifices of veins the valves are either single or double : when single, the free margin always looks towards the heart. In the canals of veins the valves are usually double in the larger, and single in the smaller. It is rare, in the human subject, to find them in threes\non the same plane, though it has been found both by Morgagni and Haller ; but in the great vessels of the larger mammalia it is common. There are none in the capillaries ; but, according to Henl\u00e9, in veins of not more than half a line in diameter, they make their appear-ance.\nFor the purposes of anatomical description a valve may be said to have a. body, margins, and cornua. The body of the valve has a cardiac, concave, or proximal face and a convex or distal face. The margins are,\u2014the free, or that which is unattached, and the attached margin. The cornua are the angles formed by the meeting of the two margins, and constitute the extreme lateral boundaries of the valve.\nValves differ from each other very considerably in form, varying from a mere linear elevation on the inner surface, in which the probe scarcely hitches as it is pushed along, to others which almost form a long isosceles triangle. The outline of the margins determines the form of a valve. Cruveilhier says that the free margin is always straight ; but this is not the fact, though it is always more so than the attached.\nIn the first attempt at a valvular formation there is merely a slight elevation of the inner surface, and the free and attached margins are nearly parallel : these scarcely constitute valves. (Fig. 863. e, e'.')\nValves, still imperfect but of larger dimensions, are found at the orifices of veins, as well as in their canals. When existing in the formel situation (and this is applicable to all valves thus placed), their attached margin corresponds with the side of the orifice which is furthest from the heart, and the outline of this margin is determined by the form of the vessel\u2019s mouth. If the lesser vessel joins the greater at right angles, the opening will be circular, and the attached margin of the valve a semicircle. If, however, the junction be oblique, and an acute angle be formed by the two vessels, then the margin attached will be drawn out of the semicircle, so as to form a sort of apex in the centre. The former of these conditions is shown at fig. 863. c, taken from a small valve at the orifice of an intercostal vein, joining the azygos ; and the latter is represented at d, which is a drawing made from a valve at the orifice of an hepatic vein, where it joins the vena cava : c' is an ideal section of the same. The dotted line in a,c and d represents, in conjunction with the line of the attached margin of the valve, the orifice of the tributary vein.\nThe next form, in order, and the one which is the most common, is the semi-lunar* valve, as it is ordinarily found in the tube of valved veins,\u2014the attached margin being nearly semicircular, and the free nearly straight {fig. 863. b). It was probably of these valves that Haller spoke when he said that the attached margin of valves constitutes a parabolic curve: it may be applicable to some of the semi-lunar,\n* Fabricius, not inaptly, described them as resembling a finger nail, \u201c forma ostiolorum ea est, ut indicis unguem imitentur.\u201d\u2014Loc. cit. p. 151.\n* Loc. cit.","page":1378},{"file":"p1379.txt","language":"en","ocr_en":"VEIN.\t1379\nbut it cannot be to valves in general : a parabola is a constant form, but the outline of the valves is various. It appears to me that the outline of a valve rather conforms to the ellipse, the curve being sometimes very much elongated, sometimes nearly approaching a circle. An ellipse is obtained from a cylinder, by an oblique section of it ; an oblique section of a cylinder will only give an ellipse. For the line of attachment, therefore, of a valve with the cylindrical surface of a vein to generate an elliptical curve, that line of attachment must coincide with an oblique section of the cylinder : and we see that this is frequently the case, that is, when the valve is viewed in profile, its attached margin forms a right line at an angle, more or less acute, with the wall of the vein, the acuteness of the angle determining the elongation of the ellipse. This is represented in fig. 864. b, where a shows the line of attachment seen in profile, and a' the curve generated by that line when seen in face. But sometimes the attached margin does not form, when viewed laterally, a straight line, but is more or less curved, as seen atfig. b, b b', and then we necessarily get\nFig. 864.\nDiagram exhibiting the Attachment and consequent Forms of Valves.\nA, section of valves in action. \u00ab, elongated elliptical valve ; b, broad semilunar valve. b, exhibits the lines of attachment of, a, elliptical valve in profile, and a', the resulting form ; b, the attachment of parabolic valve in profile, and V, the resulting form.\nan aberration from the ellipse, and an approximation, more or less near, to the parabola. Now, in such valves as are placed in pairs in the canals of veins, with their convex faces opposing and their cornua in contact, their relative length and breadth depend upon the obliquity of their attachment, \u2014 the requirements being constant, namely, that the opposed valves should meet by their free margins in aline across the centre of the vessel,\u2014 for if the attachment be oblique and extend more in the axis of the vessel, it will require a much deeper valve to reach its fellow in the centre, than if the attachment were more across the tube, where a short, broad valve would accomplish the object. These two conditions are represented in the figure {\u00dfg. 864.\na.), which is an ideal section of a vein, in which both forms of valves are seen in a state of action.\nValves in the canals of veins, though in contact by their cornua, are sufficiently loose and large to fall back fully upon the sides of the vessels to allow the progressing current to pass on uninterruptedly.\nA valve the furthest removed in form from those first mentioned, is represented in \u00dfg. 863. a, which is the drawing of a valve situated at the orifice of the emulgent vein, where it joins the inferior cava in the sheep. Its depth is very considerable in proportion to its width, and the centre of its attached margin is nearly an acute angle, produced by the angle at which the renaf vein joins the cava.*\nStructure of valves. \u2014 A venous valve consists of a thin fibrous lamina, protruded into the tube of the vessel.\nIf the attached margin be carefully cut from the wall of a vein, and the organ be extended upon a slip of glass, it is seen to be thin at the free margin and thick at the attached ; if it be viewed by transmitted light, with the naked eye, it will be seen that the body of the valve is divided, rather indistinctly, into two portions, of which the free half is thinner and bluish-white, while the other is much thicker, and of a yellowish colour ; the line of demarcation, between these, extending across the body of the valve about parallel with the free margin ; this however, does not exist, in some valves.\nThe examination of a valve with the microscope requires that it should be completely unfolded at its free margin, in the neighbourhood of which, in the larger valves, its structure can alone be successfully observed, on account of the thickness and opacity of the other parts of the valve. When removed from a vein it should be placed upon a slip of glass, moistened, and, the attached margin being seized with forceps, it should be drawn over the surface of the glass so as to unravel any folds of the free margin, which are apt to occur.\nThe epithelium cannot always be found on the face of the valve, and to see it the body must be very thin, and the focus of the instrument be thrown superficial to the fibrous lamina, when their nuclei will sometimes be viewed pretty distinctly. They are scattered evenly over the surface, but the cell-wall is extremely ill-defined, or not to be made out. At the margin of the valve they are frequently to be seen in one or two conditions,\u2014free, detached nuclei, accidentally adherent along the margin ; or cells, seen edgewise, with conspicuous nuclei, as already described.\nThe fibrous lamina is the most conspicuous element of the valve, and constitutes its bulk. It consists almost entirely of white fibrous tissue, extending from side to side of the valve, running parallel with the free margin, and continuous, apparently, with the circular coat of the vein on each side of the attached\n* The extreme depth of the valve here represented is not constant ; it sometimes barely reaches across the orifice.\n4 t 2","page":1379},{"file":"p1380.txt","language":"en","ocr_en":"1380\nVEIN.\nmargin of the valve. The fibres are singularly regular, and present the most beautiful and equal undulations, as if each fibre were of exactly the same size and extent ; and the undulations of all succeeding fibres are precisely similar, as far as the tenuity of the structure towards its attached margin is sufficient to allow of its examination. These fibres may be looked upon as a portion of the circular coat protruded into the cavity of the vein.\nFig 865.\nSmall Portions of the Valves from a Sheep.\nA,\tThe valve showing a line of epithelial nuclei at the extreme margin a a' ; a', detached nuclei ; b, small portion of face of valve, exhibiting wavy fibres, epithelium and muscle.\nB,\tthe same treated with acetic acid, a a, margin. On the face of this valve are seen two sets of nuclei; and fine threads'of elastic fibre. (Magnified 200 diameters.)\nRunning at right angles to these, and placed upon a different plane, are to be seen fibres or elongated corpuscles of a spindle shape, and of very variable distinctness. These corpuscles are apparently muscular fibre-cells: they are very conspicuous in some specimens, and very indistinct in others ; whilst in others they cannot be discovered at all.\nOn treating a valve with acetic acid, two sets of nuclear corpuscles are to be discovered, running at right angles to each other. Those which are parallel with the wavy fibres of the fibrous lamina are mainly oval, interspersed with a few more elongated ; and those, cutting the former at right angles, and being parallel with the muscular fibre-cells, are club-shaped and spindle-shaped, having a strong resemblance to the nuclei of muscular fibre-cells. The former, as it appears to me, are mainly persistent nuclei of areolar tissue, and belong to the wavy fibres, whilst the latter are evidently muscular nuclei. Small threads of yellow fibre are occasionally seen. They are very fine, detached and scattered ; and frequently exhibit a spiral form. In examining these structures it is necessary that, when removed from the body, they should not be allowed to dry before the observations are\ncompleted ; for the characters both of the fibrous lamina and nuclei are impaired permanently if they have once been dry.\nSinuses. \u2014 There is yet another item in the valvular apparatus of venous canals, \u2014 the occurrence of sinuses in the walls of the veins. These consist of small pouches or dilatations in the walls of the veins immediately in front of the valves. By these, the cylindrical form of the vessel is lost at that spot, two bulgings being apparent on it. These bulgings produce a certain amount of attenuation at these points, the thinness being in direct proportion to the increased area produced. The sinuses vary in dimensions, and do not bear any exact proportion to the size of the valve. Lateral dilatations may be seen in the walls of veins where no valves are present. ( See fig.,863., b', g, e', h.) When the valves are in action, these distended sinuses present knots along the course of the vessel ; an appearance first described and figured by Fabricius : he observes of them, \u201c non dissimilem for-mam exterius pr\u00e6 se ferentes, ac nodi in plan-tarum ramulis, et caule apparent.\u201d*\nThe supply of valves in the venous system is only partial, and is irregular. Valves are only found (in the human subject) in those veins which are subjected to muscular pressure, and are, therefore, most abundant in the veins of the limbs : and it has been well laid down by Cruveilhier, \u201c that their presence and their number, their proximity and their distance from each other are directly influenced by the degree of opposition to the onward progress of the blood in any set of veins.\u201d f\nOf the veins of the head and neck, the external jugular is the only one with valves : it possesses two, which however are not sufficiently compact to oppose injection. There are none in the cerebral sinuses or veins, and none in the internal jugular. The veins of the upper extremity are abundantly supplied with valves, which appear to be somewhat more numerous near the upper part of the arm. There are valves in the axillary vein, but none in the subclavian, vena innominata, or superior cava. They are abundant in the lower extremity, but most numerous at its lower part; in this respect differing from the superior extremity. The branches of the internal iliac vein are supplied with valves, while the external and internal iliacs themselves, the common iliac, and the inferior cava, have none. The spermatic veins (male) have valves, while the ovarian (female) are destitute of them. In the azygos veins, Cruveilhier denies the existence of valves, but they are occasionally found in an imperfect state of development.\nThe spinal veins are destitute of valves, as are, also, those of the portal system, the hepatic veins, those of the heart, kidney, uterus\n* Loc. cit. For figures of these \u201cnodi,\u201d see Fabricius, Opera omnia, tab. II. p. 157. ; also Harvey, De Motu Cordis et Sanguinis in Animalibus, Ana-tomica Exercitatio. Lugd. Bat. 1639, p. 187.\nf Cruveilhier. Anatomie Descriptive.","page":1380},{"file":"p1381.txt","language":"en","ocr_en":"VEIN.\n1381\nand lungs. Comparative anatomy and accidental aberrations from nature furnish some exceptions to the foregoing statements. Meyer has found incomplete valves in the pulmonary veins. Theile has found valves in the ovarian veins. E. H. Weber has observed them in the portal veins of the horse ; and Cuvier, in the same animal, has found them in the splenic and mesenteric veins. Haller has discovered valves in the pulmonary veins of the dog and sheep.\nValves exist but sparingly in Birds and Cetaceans ; and in Rtptiles and Fish are almost wanting.\nThe office of valves is to prevent the blood from effecting a retrograde course; \u201clest, instead of advancing from the extreme to the central parts of the body, the blood should rather proceed along the veins from the centre to the extremities ; but the delicate valves, while they readily open in the right direction, entirely prevent all such contrary motion ; being so situated and arranged, that if any thing escapes, or is less perfectly obstructed by the cornua of the one above, the fluid, passing, as it were, by the chinks between the cornua, is immediately received on the concavity of the one beneath, which is placed transversely with reference to the former, and so is effectually hindered from getting any farther.\u201d * This refers especially to the valves in the venous canals. There is a peculiarity about those placed at the orifices of veins. I have already remarked that all single valves placed at the mouths of veins are attached to the distal margin of the orifice : the free margin looks towards the heart, the concave face obliquely towards the cavity of the tributary, and the convex in the opposite direction. Now it is obvious from this arrangement, that when the blood falls back upon the concave surface of such a valve, it throws it more or less across the area of the larger trunk, and away from the orifice of the smaller vessel, over which it forms no protection. The office of the single valve, thus placed, appears to be not to guard the small veins, or to prevent the retrocessant blood from passing into it, but to oppose the blood which it supplies from passing into that portion of the recipient vein which is behind the orifice of the tributary : the valve, as it were, directs the blood into the onward track of the great vein, and prevents it from taking an opposite course.\nThe case, however, is different where the valvular apparatus is double, for there a valve is placed at the proximal, as well as at the distal margin of the orifice : now the former of these valves prevents the blood from passing behind the other into the smaller vein \u2014 the two valves mutually assist each other, and prevent the blood from passing behind either; and the result is a complete obstruction to ad retrograde circulation into the smaller vessel. The important object of exclusion of venous blood from the thoracic duct is thus effected.\n* Harvey, loc. dt.\nValves are essentially passive organs in the circulation ; and they only avail when motion is given to the circulating fluid by other means, \u2014 they determine what shall, and ivhat shall not, be the direction of the moving fluid. The contraction of the muscles is one of the great motor agents of the venous circulation. When a muscle contiguous to a vein contracts, the vessel is compressed and the blood forced out of it ; and, were it not for the valves placed at the distal side of the compressed point, the blood would be sent as much from, as towards, the heart. Autenrieth has put this in a striking point of view; he says, \u201cEach swelling muscle becomes thereby, for the neighbouring veins, a kind of heart furnished with valves ; thus, while it presses the vein, the valves prevent the blood in the lower part of the same from being driven backwards ; but, in the upper part, opening valves are placed, from which the blood, driven forth by the contracting muscle, meets with no opposition in its direction towards the heart. It is from this circumstance that each violent movement of the body, which consists in an alternate swelling up and sinking down of the muscles, has so great a tendency to accelerate the circulation ; naturally, however, while the muscles are in a state of repose, the valves cannot facilitate the movement of the blood.\u201d*\nThe function of the sinuses is this, \u2014 to receive the valves when they are folded back, during the onward current of the blood; and to allow the blood to pass behind them and to throw them across the area of the vessel when that fluid regurgitates.\nVasa vasorum. \u2014 The coats of all blood vessels, except those of very small size, are supplied with arteries and veins especially devoted to their nutrition, called \u201c vasa vasorum.\u201d\nAccording to Henl\u00e9, vessels (veins and arteries in common) receive vasa vasorum, though themselves not larger than of an inch in diameter, and sometimes even smaller. The coats of capillaries and those of the smallest vessels are not thus nourished by a separate vascular supply.\nThe nutrient arteries of the venous coats are derived from the small arterial trunks in the vicinity of the vessel j- ; they do not come directly from larger arterial trunks, but from smaller vessels; and the source of the vascular supply is determined by the particular neighbourhood of the vein \u2014 the same vessel having vasa vasorum from different sources as it passes along different regions ; thus, the vena azygos is nourished by the intercostal, pericardial, and oesophageal, arteries, according to its various relations as it proceeds along its course. The arteries supplying the tunics of a vein, appear to go promiscuously to the vessel and the adjacent tissues, sending some of its ramules to the areolar tissue, nerves, fat, &c., in the neighbourhood, and others to the walls of the vessel. In the accompanying figure, repre-\n* Autenrieth. Physiologie, \u00a7\u00a7 388, 389.\nf The artery usually has its vascular supply from, the same source as the vein which accompanies it.\n4 t 3","page":1381},{"file":"p1382.txt","language":"en","ocr_en":"1382\nVEIN.\nseating a vein from the oesophagus of an eel, magnified with low power, the vasa vasorum are seen to supply, indiscriminately, the vessel\u2019s coats and some small pellets of adipose tissue which were near it. The arteries, nourishing a vein, ramify and divide principally upon, and among, its cellular coat, and form an elaborate plexus, with meshes having a general longitudinal direction, as seen in the figure ; which,\nFig. 866.\nVasa Vasorum on external surface of a small Vein from the oesophagus of eel. ( Anguilla acutirostris.')\na a, vein; b b b, small arteries supplying indiscriminately the venous tunics and small masses of fat around the vein ; c c c c c, granules of adipose tissue. Natural injection. (Magnified about 18 diameters.)\nthough drawn from a fish, sufficiently indicates the condition as found in man and mammals. The arrangement of these capillaries is, however, subject to variety : in the vena cava of the cod, I have seen them long, straight, even, and perfectly parallel, with scarcely any transverse branching or anastomosis. The little venous trunks of the vasa vasorum usually open directly into the cavity of the vein, among whose tunics they have previously ramified, and their course is quite independent of the corresponding arteries. (Henl\u00e9.)\nThe vasa vasorum principally exist in the areolar tunic, but Henl\u00e9 states that they are to be found abundantly among the annular fibres of the veins.* The internal longitudinal coat is, in all cases, extra-vascular.\nNerves of veins. \u2014 As far as our knowledge hitherto goes, veins differ remarkably from arteries in rarely being made the support of\n* In arteries, Weber has never found them in the circular tunic. Burdaeh states that he has found a few.\nnerves, and in seldom receiving any distribution of them to their coats. It is a remarkable circumstance that veins appear, with slight exceptions, to be separated from nerves. The exceptions to this rule are few and inconsiderable.\nThe inferior vena cava receives some small filaments from the diaphragmatic ganglion of the sympathetic, just below the diaphragm. The vena porta supports and is entwined by the branches of the hepatic plexus, which it conducts to the liver. Pappenheim describes some nerves as being distributed to the cerebral veins. Bidder states that he has traced some filaments of the fourth cerebral nerve to the lateral sinus: and Wrisberg describes a nervous plexus as surrounding the facial vein, which he ingeniously imagines may cause contractions of the vein, and thereby produce that congestion of the face constituting blushing.\nIn the cod-fish (Gadus morrhua), I have traced nerves from the auricle down upon the venous sinus immediately below it : these formed loops in the walls of the sinus, and appeared to return to the heart. The nerves in question are doubtless a continuation of the cardiac nerves ; and, in all probability, bear the same relation to the rhythmical action of this pulsating cavity, which the other cardiac nerves do to the cavities of the heart itself.\nIt is very probable that some such nervous supply is furnished to those parts of the veins of man and mammals, near the heart, in which cardiac muscle is found.\nIt may, perhaps, be still a question whether the almost complete non-nervous character of veins is absolutely correct, and whether the paucity or tenuity of the nerves, supplied to veins in general, be not the reason why they have as yet eluded observation; for analogy scarcely justifies the idea of organs possessing muscular tissue and still being destitute of nerves. This opinion is strengthened by the fact that arteries, having the same sort of muscularity as veins, though in larger amount, are regularly supplied with nerves.\nComparative structure. \u2014 I am not aware of any observations upon the comparative structure of veins in birds and reptiles. Those that I have myself made are principally introduced under the heads, Fenestrated membrane, Epithelium, tfc.\nIn Birds, the venous walls are composed principally of areolar tissue, external to the lining membrane; and I have observed that in the diving-birds, the vena cava posterior is composed almost solely of elastic tissue. There are no muscle-cells in the cerebral veins of birds.\nIn Fishes, the venous parietes appear to be formed of a sort of areolar tissue longitudinally disposed. Embedded in the walls of the veins there is an abundance of pigment, which exists in greater quantity in the intercostal veins, and those tributary to the cardinal vein. This pigment is of the variety called by Schwann \u201c stellate pigment cells,\u201d","page":1382},{"file":"p1383.txt","language":"en","ocr_en":"VEIN.\t1383\nand consists of branched cells, of a black colour, and various form. The body of the cell is generally some modification of an oval or oblong, and lies with its long axis corresponding to that of the vessel ; and from its extremities caud\u00e6 project, of every imaginable shape and proportion, of larger size than those which project from its sides, which are few and small. The body of each cell appears to be occupied by its nucleus.\nFig 867.\nVeins from Fish exhibiting Pigment cells.\nA, vein from muscle of eel (Anguilla acutirostris) (.Magnified 50 diameters'), b. vein from muscle of sole ( Solea vulgaris) (Magnified 100 diameters). c, little mass from the external surface of the cardinal vein of the eel (Magnified 200 diameters.)\nIn the accompanying figure, some of these cells are represented from the eel (Anguilla acutirostris), and sole (Solea vulgaris), which present considerable variety of form. They also vary in the same individual in different situations : in the cardinal vein they are most numerous and aggregated ; in smaller veins they are less numerous and more distinct ; and in those of minute size, they only occur here and there at considerable intervals, and at the spots where they are placed they occupy nearly the whole face of the vessel.\nWhen submitted to high microscopical power, these cells are seen to be mixed up with the tissue of the venous coats, and their thin branched extremities have, in some places, much the aspect of elastic tissue, in the uniformity of their dimensions and their dichotomous divisions.\nCaudal venous heart of eel. \u2014 Dr. Marshall Hall, in 1831, first figured and described a peculiar pulsating organ which exists in the tail of the eel, calling it by the name of \u201c caudal heart ; \u201d and he considered it to be a muscular\nventricle, by whose contractions the blood is propelled in the vein at the commencement of which it is placed.\nRusconi has differently interpreted this organ, and calls it a lymphatic heart, believing that it is perfectly analogous to those pulsating sacs, which are found in certain parts of the lymphatic systems of various reptiles. And certainly the occurrence of a little pulsating organ, having the form, colour, and general aspect of the lymphatic hearts in the frog, situated in the vicinity of the venous system, having an action independent of the systemic heart, and existing in a cold-blooded animal, is, from analogy, enough to suggest the idea that Rusconi\u2019s view is the correct one. But this is not confirmed by anatomy, for after repeated and numerous observations of this heart, I am convinced that the original description of it, given by Dr. Hall, is the truth.\nThe caudal heart is to be found in eels of all sizes, but is best seen in small individuals a few inches in length, on account of their clear skin, and the larger proportional size of the organ in them. It may be seen by holding the eel\u2019s tail between the light and the eye of the observer, either with a lens, or without the aid of any magnifying power. It may be conveniently examined with the microscope by wrapping the head of the animal in a wet cloth, and then applying its tail to a slip of glass, and placing it under the field of the instrument ; but the extreme restlessness of the little fish sometimes renders it necessary that it should be partially-or completely stunned before it can be viewed. The heart is then seen to be\nA and b represent two forms, a, the heart : b cardinal vein ; c sinus that receives the blood from the capillaries ; d, minute veins from caudal fin.\nplaced near the extremity of the cardinal vein, on the haemal aspect of the caudal vertebrae at the end of the tail. It is of a yellowish colour, chequered more or less with stellate pigment, and of a form varying from a pear-shape to a spindle-shape. (Fig. 868.) At the distal extremity it is connected with a small vein, which collects the blood from the capillaries of the tail ; at its proximal extremity it is connected with the commencing cardinal vein ; or it may be said that on 4 t 1","page":1383},{"file":"p1384.txt","language":"en","ocr_en":"1384\tVEIN.\neither side is the cardinal vein, and that the heart is a muscular development on the coats of that vessel. The action of this heart appears to be quite independent of the branchial heart ; for, as Dr. Hall observes, \u201c whilst the latter beats sixty, the former beats one hundred and sixty times in a minute. It continues for a very long time after the influence of the pulmonic heart is entirely removed.\u201d * I have never seen the action of the caudal heart quite so rapid as is described by Dr. Hall : in one individual, partly torpid from cold, it contracted but sixty times in the minute ; but when this fish was warmed, the number rose to one hundred and two, \u2014 the beats of the branchial heart being less than half the caudal.\nThe blood, which is deep red, appears to flow into the extreme end of this organ in a continuous stream, but is forced out at each contraction from the other aperture in an interrupted current. The absence of any regurgitation, at the further end of the heart, would suggest the presence of some valvular apparatus there situate. The jet of blood, sent forward at each contraction, may be beautifully seen by holding up the tail of the eel to the light ; it is seen as a regular, arterial, per-saltum, jet, passing along the vessel in front of the heart, which, in the intervals of each contraction, is empty: as Dr. Hall expresses it, the blood is \u201c propelled with great velocity, at first with the appearance of successive drops.\u201d j- This per saltum current only exists a short distance, and gradually degenerates into a continuous, venous, stream. When the parts are submitted to low magnifying power, I have observed that at each systole of the heart the veins at the distal extremity of the organ are violently tugged in the longitudinal direction (produced by the shortening of the heart in its contracted state), and this exists as far as several ramifications from the heart (d! d'). A movement in the opposite direction takes place at the diastole, which is doubtless assisted by the elasticity of the vessels restoring them to their former length. This circumstance, moreover, proves the complete continuity of structure of this organ with the small vessels which furnish the blood upon which it contracts.\nI have seen this best when the tail has been cut from the body,\u2014 the bloodless heart still going on contracting.\nI have failed altogether to find any lymphatics going to this pulsating organ ; and the facts which I have already adduced, that it receives blood from behind, and transmits it forwards; the large aggregate quantity of fluid which it propels in a given time ; the rhythmical tension of the capillary veins, attached to the distal end, at each contraction, as well as the apparent absence of lymphatics, seem to prove that it is a blood, and not a lymph, heart.\n* Hall\u2019s Essay on the Circulation, p. 172.\nj- Loc, cit.\nII. Physical and Vital Properties.\u2014 As it regards the physical properties of veins, it may be remarked that their walls are thin as contrasted with arteries of the same calibre, those of the upper extremity being less than those of the lower; they are somewhat looser in texture, especially externally, and more extensile in the transverse direction \u2014 are distensible, and when distended they do not readily return to their former dimensions ; both circumstances being due, in a great measure, to the general longitudinal direction of their fibres : according to Soemmering the resisting power of veins diminishes with advancing age.\nThe walls of veins are elastic, though less so than arteries, which pre-eminently exhibit that quality.\nThe extreme thinness and slight physical resistance of veins is the cause why they collapse when empty.\nAn empty vein presents very fine longitudinal rug\u00e6 on its inner surface.\nThe tissue of veins is less distinctly yellow than arteries, and frequently is stained of a pinkish colour by the blood in contact with it.\nThough their physical properties are, for the most part, of a negative character, they nevertheless possess the property of tenacity to a great degree, and are at least as strong as arteries of the same capacity, though the substance of the latter is so much more considerable.\nLigature applied to a vein produces a longitudinal folding of the walls, which is very apparent when the vessel is laid open after it has been tied. An indentation is produced across the inner surface of the vessel at the line of ligature, caused by the complete or partial rupture of its thin inner, longitudinal, fibrous tunic. But the entire thickness of the wall appears to have undergone a partial cut, as though one element of the compound mass of which it is composed had been divided while the rest remained entire ; and it would seem probable that a ligature applied tightly around a vein would divide the crisp yellow elastic tissue, while the tenacious white fibrous element, with which it is mixed, would remain entire. This probable explanation I have found, upon microscopical examination, to be correct; the two parts, therefore, of a vein that, has been ligatured, are held together by the white fibrous tissue that enters into the constitution of its walls.*\nVital Properties of Veins. \u2014 I am not aware of any experiments which have been directed to decide the amount of sensibility possessed by veins : it is probably, judging from anatomical grounds, exceedingly low.\nAs regards vital contractility, it has been a matter of dispute whether veins possess that property or not. Soemmering held them to possess it in an eminent degree, especially under the influence of chemical stimuli, whilst\n* For some beautiful illustrations of ligatured veins, I would refer to Cooper and Travers\u2019s Surgical Essays, vol. i. plate 12.","page":1384},{"file":"p1385.txt","language":"en","ocr_en":"VEIN.\n138.5\nHaller * denies that they are endowed with irritability. It is now placed beyond all question that veins are endowed with vital contractility, and that it exists in them in two distinct and entirely separate forms \u2014 first, as a rhythmical contraction, similar to what occurs in the cardiac cavities ; and secondly, as that peculiar slow and prolonged contraction which is known as tonicity, and which in so striking a degree exists, and exists alone, in arteries, \u2014 the former occurring in a small portion of the venous track, the latter pervading nearly the entire venous system. To the establishment of this last physiological fact, we are mainly indebted to Professor K\u00f6lliker.\nVenous rythmical contraction in man and mammalia generally occurs only in the immediate neighbourhood of the heart, but in cold-blooded animals it extends a considerable distance along the venous trunks. Flourensf was the first to describe it in the frog, where it has frequently been since witnessed ; and M\u00fcller has observed that the venous trunks of the frog continue to contract even after the removal of the heart and the auricle.\nNysten has witnessed contraction of the upper part of the vena cava in fish ; and Wedemeyer has observed the same in other cold-blooded animals. According to Muller the rhythm of the veins in frogs occurs just previous to that of the auricle, and the rhythm of the auricle before that of the ventricle, and the rhythm of the aortic bulb follows the ventricular : there are four successive contractions, of which that of the veins is the first.\nIn mammalia the venous contraction is almost synchronous with the auricular. I have frequently witnessed it in vivisect animals\u2014rabbits, kittens, &c. ; and it exists in the pulmonary veins as well as in the cav\u00e6. It is only in the immediate neighbourhood of the auricles that the veins contract, doubtless just so far as the cardiac muscle is prolonged into the venous tissues. The rhythm appears to commence upon the vein and pass forward upon the auricle. This vascular rhythm, existing in a high degree in the lower vertebrata, and diminishing in the higher, would appear, in man, to be the last remnant of the tubular heart seen in the in vertebrata.\nIt appears very probable that the contraction of the veins close to the auricles may be of assistance in the economy of the heart\u2019s action. If it be recollected that the auriculo-venous orifices are not guarded by valvular apparatus, it will be difficult to explain how, when the auricles contract, the blood is prevented from flowing back into the patent veins : may not this be prevented to a certain extent by the contraction of the veins, which thus constitute a sort of sphincter ? This rhythmical action of the veins must in no way be confounded with that peculiar venous\n* Sec. M\u00e9m. sur les part, sensibles et irritables : and Elem. Phys. lib. ii. p. 126. and lib. vi. p. 125.\n\u2022f In Annales des Sciences Natur, tom. xxviii. p. 65.\npulsation which exists in certain forms of disease. Venous tonicity has lately been established by K\u00f6lliker*, and his physiological experiments have been based upon and fortified by the most conclusive anatomical discovery \u2014viz. the demonstration of unstriped muscular fibre in the walls of veins.\nProfessor K\u00f6lliker\u2019s experiments were made upon the veins of a leg immediately after amputation ; and the agent of muscular excitation was an electromagnetic apparatus.\n\u201c The vena saphena minor was touched in the fossa poplitea, on the lower part of the leg and on the foot; the vena saphena magna on the lower part of the leg and dorsum pedis. A few seconds after the application of the wire, contraction took place ; at the end of a minute the parts touched contracted so much, that the blood that they contained in large quantities was pressed out, until the vessel had the appearance of a white cord. On smaller veins of the skin, the effect was not so rapid or so powerful.\u201d\n\u201c Three applications of the wire had no effect on the vena poplitea, but it was already very flaccid and empty before the experiment. The vena tibialis postica was empty by contraction in a minute.\u201d\nThe irritability endured in the veins for an hour and fifteen minutes, being somewhat longer than in the arteries and lymphatics, and shorter than in the muscles.\nThis contractile power in veins is of that peculiar character which has long been known to exist in arteries : it is slow, gradual, and persistent, and by it the vessel is braced up and set at a given calibre. This contractility, combined with the elasticity of the vessel\u2019s walls, is the antagonist to the distending force of the blood within the vessel.\nI have frequently noticed in animals examined during life, that the large venous trunks are of greater calibre than when viewed after death : that whilst the blood flows on through the vessel, it is distended to a larger size than when from exudation and other causes the quantity of distending fluid is diminished ; just as at each jet of blood passing through an artery the tube is distended, in opposition to its contracted state after death,\u2014the explanation being undoubtedly this, that immediately after death the vein-muscle becomes affected with cadaveric rigidity, and this being unopposed by the distending blood, contracts the vessel to a calibre less than that which it could hold whilst the contraction was opposed by the distending force of the circulating fluid. The same thing occurs more distinctly in arteries, and, whilst the rigor mortis remains in activity, forms a powerful opponent to injections.\nIII. General Remarks upon Veins \u2014 Origin ; Course ; Anasto\u00bbioses ; Plexuses, &c.\u2014 General considerations of veins are to be made principally in relation to arte-\n* K\u00f6lliker and Siebold\u2019s Zeitschrift. 1849.","page":1385},{"file":"p1386.txt","language":"en","ocr_en":"1386\nVEIN.\nries, in contrast with which the characteristics of the former are most conspicuous.\nThe general, the pulmonary, and the portal venous systems may be looked upon as the roots of a tree, the trunks of which would correspond with the auricles and the porta ; or they may be viewed as three cones, the bases of which are the capillaries of each system, and the apices, the auricles, and the porta. In either view, the veins are to be examined, in their track intermediate between these two points, as to their number, size, relation, and modes of dividing and junction. These observations will be carried solely as far as they refer to the general circulation, and that principally as it affects the human subject ; the pulmonary and the portal systems being more properly considered in conjunction with those viscera with which they are connected.\nThe venous system is far more extensive than the arterial, both as it regards size and numbei' of vessels.\nAttempts have been made by different anatomists to estimate the relative size of arteries and veins, though it is difficult to see upon what data any thing like an exact calculation can be based ; nevertheless, Sauvages states the capacity of veins, as compared with arteries, to be as nine to four, Haller as two to one, and Borelli as four to one. Though it may be impossible to say which of these is the true estimate, it is obvious that the disparity between the two sets of vessels is very great. In the extremities and head, indeed everywhere but in the viscera, the veins form two distinct sets, the superficial, subcutaneous, veins, and the deep veins accompanying the arteries. These latter, which are called satellite veins (pence comit\u00e9s), are almost always double\u2014two veins accompanying each artery of the same name. \u201c This rule, however, has some exceptions ; in fact there is only one accompanying vein for most of the great arterial trunks, and even for some arteries of moderate size ; lastly, in some few instances there is but one vein to two arteries. Thus, there is only one superior and one inferior mesenteric, one renal, and one external iliac, vein, each of which corresponds to the artery of the same name ; but there is only one umbilical vein to two umbilical arteries, and there are several suprarenal arteries, but only one suprarenal vein.\u201d (Cruveilhitr.) These exceptions, however, are not sufficiently numerous to alter the diffuse and branching character of veins. The following apposite quotation upon this head is from Meckel :\u2014\u201c It is a universal law with veins, that the branches or ramifications are larger in comparison with the trunks than in the arterial system ; the veins of a part, or even of the whole body, never uniting themselves to so small a number of stems as those out of which the arteries take their origin. The aorta and pulmonary artery originate as single stems out of the respective cavities of the heart; the systemic veins, on the contrary, terminate in three trunks, the superior and\ninferior cav\u00e6 and the coronary vein ; moreover, the superior cava receives, but just before its entrance into the heart, a fourth trunk \u2014 the azygos vein. The pulmonary veins terminate in four, five, or even six trunks into the left auricle. Again, in the extremities,\u2014take the arm, for instance,\u2014 where there is but a single artery, there are four considerable venous trunks. Thus division is the character of the arrangement of the veins ; contratension that of the arrangement of the arteries.\u201d (Meckel, Handbuch der menschlichen Anatomie, Band i. S. 201.)\nOrigin of Veins.\u2014Veins originate, almost without exception, by the capillaries uniting \u2014 increasing in size, and diminishing in number. This fact has been known, and all but universally received, since the days of Malpighi, who (in 1661) demonstrated, by microscopical research, that portion of Harvey\u2019s system of the circulation which had not been displayed, \u2014 the passage of the blood intermediately between the arteries and veins,\u2014 the capillaries, \u2014 and thereby explained the origin of the veins. That veins originate only by capillaries has also been generally admitted ; but Haller has described absorbent veins as arising from all free surfaces ; and Cruveilhier speaks of veins commencing with open mouths on the surface of all mucous membranes ; opinions long since refuted. There appear, however, to be some exceptions to this general rule of capillary origin of veins. Thus, the veins which return the blood from certain portions of erectile tissue would seem to commence as little venous caverns or sacs, into which blood is poured by arteries of a size much above capillary vessels. (Valentin : Millier.)\nMr. Paget has recently pointed out another mode of venous origin as occurring in the wing of the bat (Vesperlilio), where arteries of comparatively considerable size pass at once into veins without intermediate capillaries. Mr. Paget observes: \u201cVery generally the arteries of the second and third order of branches pass into veins of corresponding size without any intermedium of capillaries. The capillaries are rather in the position of offsets from the continuous channels of arterial and venous loops, than in their more ordinary relation as intermediate canals leading from arteries to veins.\u201d* Further research, especially in comparative anatomy, will probably exhibit other instances of peculiar venous origin.\nCourse, Anastomoses, Plexuses, fyc. of Veins. \u2014 In travelling from their commencement to their termination, veins follow very various courses, the most marked differences indicating a division into those which accompany their corresponding arteries, and those which pursue an independent course; a division which corresponds, with a few exceptions, to the deep and the superficial veins.\nIn commencing, the veins form networks of\n* Lectures on Inflammation, by James Paget, F.R.C.S., in Medical Gazette, vol. xlv. p. 968.","page":1386},{"file":"p1387.txt","language":"en","ocr_en":"VEIN.\n1387\nvessels, which unite and reunite till they form venous trunks, which then take a more or less direct route to the heart.\nThe deep veins accompany the corresponding arteries, and pursue the same course as these latter vessels, having similar relations with the bones, muscles, nerves, and fasci\u00e6 : they are moreover surrounded by the same sheath of condensed areolar tissue as the arteries. It is remarkable, as has been observed by Cruveilhier, that the relative position of the two kinds of vessels, although constant, does not seem to follow any general rule ; all attempts to ascertain any law by which the relations of the veins with the arteries are regulated have been unsuccessful.\nIn some situations deep veins do not take the same course as the corresponding arteries. This is the case with those of the nervous system (the cranial sinuses and spinal veins), the hepatic vein, the ophthalmic vein, the azygos vein, &c.\nThe superficial or subcutaneous veins follow an independent course, as respects arteries, and accompany the cutaneous nerves and lymphatics in the interval between the muscular aponeuroses and the skin.\nThe anastomoses of veins, and the plexuses formed thereby, are abundant and elaborate. The inosculations are more numerous than those of arteries, and occur by means of much larger vessels. They take place \u201c by direct inosculation, by lateral, transverse, or oblique, communications, and anastomoses by convergence, which are found in every situation and with all conceivable varieties. The branches of the veins form lozenge-shaped meshes ; and both the trunks and the branches communicate freely with each other ; that is to say, the superficial with the deep set, the veins of the superficial set and those of the deep set amongst each other, and the vena cava superior with the vena cava inferior : so that we may say that the whole venous system forms one vascular network ; and it is by these free communications that such obstacles as impede or completely intercept the course of the blood in a given part are rendered incapable of stopping it altogether.\u201d (Cruveilhier.)\nThe anastomoses are so numerous and complete, that it is almost impossible to intercept the venous circulation by the interruption even of vessels of considerable size : if even the superior cava with the venae innomi-nat\u0153 be interrupted, the blood will be returned\u2014 finding its way back to the heart by the anastomoses of the internal mammary, the acromio-thoracic veins, &c. with the intercostal, azygos, and epigastric veins \u2014 so taking the blood back by means of the inferior cava. An obstruction of the inferior cava is compensated for by the same set of vessels, the blood going then in the other direction.* Obstruction to the portal circulation does not absolutely stop the blood : inosculations occur between the portal and general systems\n* See Morbid Anatomy.\nof veins in the haemorrhoidal plexus sufficient to maintain the blood-current.\nThese are some of the special examples of anastomoses ; the general method of inosculation also requires some explanation. For example, a vein arises in conjunction with another collateral vein, or takes its origin from the latter, and after having pursued a course of various length, again joins the principal vein. Instances of this may be seen in the various veins of the extremities.\nA venous trunk may divide p- 0gg_ into two of equal size, which separate at a very acute angle, and, after an elliptical interval, again unite into one. Such may frequently be observed in the saphoena.\nCross anastomoses, by means of large veins uniting those on the opposite sides of the body, are not unfrequent. Such are the circular sinus and the basilar sinus, in the skull, the azygos, and the intercostal veins, &c.\nA vein, just before its junction with the trunk to which it is tributary, divides into two, and joins at different parts \u2014 an occasional variety of the frontal vein.\nThe plexuses of veins are merely a high degree of anastomosis : they are not subservient to any laws in their formation and arrangement, or susceptible of any systematic division ; and will probably be best understood by describing and figuring a few of the most characteristic.\nThe simplest and most primitive form of plexus is that which is produced by the inosculations and joinings of two ven\u0153 comit\u00e9s around and across an artery.\nSuch is exhibited in the accompanying figure : the anastomoses are so numerous, that it is difficult to tell in parts whether they are to be considered as two vessels, or as one, with frequent trivial interruptions of cavity : at some points they run a considerable distance without conjunction,leaving an elongated elliptical interval ; and at other points 'their confluence is so great that the intervals are reduced to small circular apertures on the face of one broad vein.\nA coarser and more complicated form of plexus is exhibited in the subcutaneous system of veins, in the production of which Ven\u00e6 m{feg several venous trunks combine, Spermatic\u0153. and by their lateral branchings (afterBreschet.) and confluxes produce diamondshaped, rhomboidal, and triangular inter-","page":1387},{"file":"p1388.txt","language":"en","ocr_en":"1388\tVEIN.\nspaces : \u2014 these anastomoses being all on the same plane, excepting at a few points here and there where a small channel dips down to the deep veins. Such plexuses may be seen on the dorsum of the hand and foot.\nBut the most elaborate and complex of all the plexuses in the human* subject are those formed around, about, and within, the spinal canal : they are composed of numerous trunks, which unite, divide, and re-\nFig. 870.\nPlexuses connected with the Spinal Canal.\na, the great anterior spinal veins (the, \u201cgrandes veines rachidiennes longitudinales ant\u00e9rieures''' of Bresehet) ; b, ascending lumbar veins (the \u201c veines lombaires ascendantes \u201d of Bresehet) ; c, veins uniting the above-mentioned, through the intervertebral foramina (after Bresehet).\nunite, at every possible point, and in all conceivable modes, by branches of all sizes, lengths, and shapes, and leave intervals presenting forms of endless variety. A portion of these plexuses, seen in the accompanying figure, from Breschet\u2019s work on the veins, conveys a better idea of them than any lengthened description.\nThe diploic plexuses are the net-works of veins which exist in and among the cancellated tissue of the bones. In the flat bones of the cranium, at the period of adult life, they form large irregular meshes, by the mean-derings of large, irregular, ampullated, veins. These vessels are very unequal in size, are subject to dilatations, and frequently end in culs-de-sac. They are well represented in figs. 187. and 188. Vol. I. But the most remarkable peculiarity in these plexuses, is the change they undergo during osseous development. In early foetal life, when ossifi-\ncation commences the cranial bones consist of stell\u00e6 of numerous ossifie rays, the interspaces between them being occupied by hosts of small, almost straight, radiating, veins: these veins are not covered in by osseous structure, but are exposed on both surfaces of the bone (fig. 872.) ; they then gradually become tortuous, and fuse into one another, so as to diminish in number, and lose much of their radiating character ; and after a time they become covered by a thin plate of bone on either surface. The process of fusion and dilatation of the veins still goes on during life, and ultmately leaves the diploic plexus, consisting of a few large vessels. Diploic vessels exist in all cancellated bone in various plexiform combinations. In the loose texture\n* In birds the intra-spinal plexuses are so large and dense that it is with difficulty that the anatomist can make out that they are not extravasations.","page":1388},{"file":"p1389.txt","language":"en","ocr_en":"VEIN.\n138fr\nof the bodies of the vertebr\u00e6 remarkable plexuses exist. (Fig. 87 1.)\nFig. 871.\nDiploic Veins in a Vertebra, a, great anterior spinal veins ; b, posterior spinal veins ; c, transverse branches ; d, ven\u00e6 basis ver-tebrarum ; e, vein on the surface of the body of the vertebra. (After Dreschet.')\nFig. 872.\nParietal Bone of F\u0153tus at nine months, exhibiting the veins. (After Breschet.)\nIV. Function of Veins. \u2014 In function veins may be considered as having a triple office : they are passive organs of circulation; they are diverticula or reservoirs for blood ; and they are agents of absorption.\nCirculation in the veins consists of the passive and equable transmission of blood along their tubes. \u201c When we consider the great size of the veins, compared with the arteries, we must conclude that the blood flows but slowly in the venous system ; that, from the narrowness of the trunks of the veins near the heart, the blood must be accelerated as it approaches the heart ; and that receiving the impulse from the ventricle, it must take a rapid course through the arteries, until, again approaching the extreme branches of the arteries, and passing into the veins, its motion becomes more languid and slow. In youth, as the size of the veins is not in so great a proportion to the arteries as in advanced life, the blood must be in more rapid circulation : but in old age, owing to the largeness of the veins and the accumulation of blood in them, it moves slowly through the venous system, and is almost stagnant in the dilated veins and in the sinuses.\n\u201c There is no pulsation to be observed in the veins, but what they receive from contiguous arteries. There is no pulsation in the veins because they are removed from the heart ; because they do not receive the shock of the heart\u2019s action in their trunk, but only by their widely-spread branches ; because the contraction of the heart and of the arteries so alternate with each other, as to keep up a perpetual and uniform stream of blood into the veins.\u201d (Sir C. Bell\u2019s Anatomy, vol. ii. p. 284.)\nAs diverticula and reservoirs of blood the veins must be considered as performing a most important service in the ceconomy of the circulation. There are numerous circumstances both in health and disease which either temporarily or permanently disturb the balance of \u201ethe circulation, and thereby displace and choke up large quantities of blood ; and, were it not for the reservoirs, diverticula, and lateral compensating channels, which are afforded by large, bulging, and dilatable veins, by the enormous area of the common venous cavity, and by the numerous and elaborate inosculations and plexuses which these vessels every where exhibit, such interruptions might lead to consequences, permanent, irremediable and destructive.\nThe whole subcutaneous system of veins must be looked upon as a series of compensatory channels. The cavities of the deep veins are quite sufficient to return the blood that is sent to them by vessels of smaller aggregate calibre. But during muscular exertion, &c., these deep vessels are impeded by pressure, and then the blood finds a collateral route by means of the subcutaneous veins. So again, when from cold, or other causes, the skin-muscle contracts and presses on the cutaneous veins they are more or less emptied, and their office is resumed by the deep veins : they thus keep up a mutual reciprocation of function.\nThe large internal veins of the body; the","page":1389},{"file":"p1390.txt","language":"en","ocr_en":"\u00ce390\tVEIN.\ndilatations of the veins at the base of the brain ; the large amount of veins in the parenchymatous viscera ; the venous plexuses of the spinal canal, together with the venous cells and tubes in the cancellated tissue of all bones, form a series of diverticula and reservoirs, equal to all emergencies*, where the blood may slowly flow, or recede, or stagnate. But the most striking examples of venous reservoirs are furnished by comparative anatomy. All those animals which have diving habits subject themselves to peculiar disturbance of circulation. The prolonged stoppage of respiration, but still more the immense pressure of water to which they are exposed, when deeply submerged, mechanically empties all the superficial veins and produces much deep-seated and visceral congestion. This is compensated for by a special arrangement. In diving birds there is great dilatation of the posterior vena cava. In the Grebes and Divers (Podiceps and Co/ymbus) the posterior cava is largely dilated in the liver and below, extending to opposite the kidneys. In the Cetacea, which are subject to the same influence, enormous dilatable venous plexuses, placed within the abdominal cavity, perform the same office.\nVenous absorption probably occurs wherever veins exist, but especially in the alimentary canal, where, in conjunction with the lacteals, they perform the important office of extracting from the food the different materials which enter the circulation and nourish the various tissues of the body.\nIt is not my intention to enter upon any of the elaborate arguments or disquisitions on the evidence of venous absorption. I shall co\u00fbtent myself with a brief summary of the most important salient points.\nThat absorption by the veins takes place independently of the lacteals has been proved by a series of conclusive experiments conducted by Tiedemann and Gmelinf, who administered to a number of animals various substances of distinct and easily recognisable physical and chemical properties, and afterwards analysed the venous blood, the secretions, and the chyle. Substances having deep colours, such i'.s cochineal, indigo, litmus, gamboge ; substances having strong odours \u2014 turpentine, assafoetida, garlic, musk \u2014 and saline substances, such as sulphate of iron, chloride of barium, ferro-cyanide and sulpho-cyanide of potassium, were all in turn submitted to experiment. Almost all of these matters were found in the venous blood, several of them in the urine, and a few only of the latter (the saline substances) in the chyle. Therefore it appears that absorption did take place, in many instances, independently of the lacteals, and\n* Not literally equal to all emergencies: the great deep-seated congestion caused in the cold stage of an ague-fit has ruptured the vena cava : the same has occurred in violent muscular exertion.\nf Versuche \u00fcber d. Wege auf welchem Substanzen aus dem Magen u. Darmkanal ins Blut gelangen. Heidelberg. 1820.\nby the veins. This conclusion is fortified by other experiments conveying both positive and negative evidence, which have been performed by Majendie, Blake, Delille, Segalas, &c.\nMajendie and Delille in conjunction performed the following experiment. They severed all the parts of* the posterior extremity of a dog, excepting the artery and vein by which the circulation of the limb was kept up. They then introduced some upas poison into the foot; and in ten minutes the animal died. It cannot be imagined here that the lymphatics absorbed the poison, as they were divided ; but it may be objected that the matter was mechanically introduced into the divided extremities of the vessels in the wound. This difficulty has been overcome in another experiment devised by Majendie. He found that death was caused by the introduction of nux vomica into the intestine of an animal in which the lacteals had been tied, where the veins, by which alone absorption could here take place, remained entire. An experiment exactly the reverse of the last was performed by Segalas, which completely bore out the idea of venous absorption. Instead of tying the lacteals and leaving the veins untied, Segalas tied the veins, the lacteals remaining unimpaired. The result was, that when poison was applied to the intestine, no absorption took place, and no result followed. It was further found by Mr. Blake, that ligature of the vena porta prevented the action of poisons introduced into the stomach.\nV. Development of Veins. \u2014 Are the veins, large and small, originally developed as capillaries, the succeeding changes by which their texture and size are modified taking place subsequently to their being permeable sanguiferous channels ? Whether this is entirely the case is doubtful : that it is so to some extent is certain; and therefore the development of veins would involve two considerations \u2014 first, the development of capillaries, and secondly, those after-changes by which the vessels cease to be capillaries, and become, in texture and volume, true veins.\nThe arguments in favour of the view that veins are developed primarily as capillaries, are \u2014 that veins, arteries, and capillaries constitute one continuous system, which renders a community of development antecedently probable ; that arteries and veins are so similar in structure as evidently to possess a common development, which heightens the probability of their development being the same as their connecting link; that the part possessed by capillaries \u2014 basement membrane \u2014 is that which we see in other parts capable of giving rise to fresh structures ; that we see all stages between the largest veins and capillaries filled up without a gap ; that structures which in an early stage are furnished only with capillaries, and vessels a little removed from them, are found shortly","page":1390},{"file":"p1391.txt","language":"en","ocr_en":"VEIN.\t1391\nto contain veins, and that the venous textures become more strongly marked as the parts become more mature ; and that veins but little removed in size from capillaries, differ from them by the addition of structures exactly similar in nature to those which larger veins possess in a greater amount.\nThe development of capillaries has been observed, principally, by Schwann* in the tails of young tadpoles, and the germinal membrane of an incubated hen\u2019s egg, by K\u00f6llikerf, in the tails of batrachian larv\u00e6 generally, and by Paget J in the foetal membranes of sheep. Their accounts, which my own observations on the tails of batrachian larvae entirely confirm, all substantially agree.\nOn subjecting the tail of a very young tadpole to microscopical observation, and viewing it with an object glass of a quarter of an inch focal distance, it willjje seen that the vessels possess all the characteristics of veryfine capillaries, that is, they possess a delicate, perfectly homogeneous membrane, with nuclei adhering here and there to its internal surface. The two great arterial and venous trunks are elongated posteriorly, as the larvae grow, by throwing out prolongations, which, by joining the embryonic cells accumulated about the extremity of the chorda dorsalis, inosculate with them so as to form a continuous cavity. The first lateral vessels of the tail, which have the form of simple arcs going from artery to vein, are formed by the junction of prolongations, from the caudal artery and vein, with certain elongated or stellate cells in the substance of the tail. From these vessels, which constitute what may be called the primary arches, are thrown out projections which, by inosculating in an exactly similar way with neighbouring stellate cells, form secondary capillary arches ; and thus the capillary network continually extends itself in proportion as the tail gets longer and broader, and at the same time becomes more dense b}r the formation of new vessels between the primitive meshes.\nSuch are the general appearances seen in the tail of any of the batrachian larvae. These, however, Schwann does not consider so conclusive as the appearances in the germinal membrane of a hen\u2019s egg. He says that when the germinal membrane of a hen\u2019s egg which has been subjected to thirty-six hours\u2019 incubation, is placed under the microscope, and the area pellucida examined with a magnifying power of 450, the capillary vessels are readily distinguished in it. In some situations they are perfect, and connected with the larger vessel, some are of irregular calibre, having bulgings here and there where two or three channels meet, the intervening portions varying in size from that of a fibre of yellow fibrous tissue to the full capillary diameter, and permeable to blood or not.\n* Microscopical Researches, translated for the Sydenham Society, by Henry Smith.\nj- Annales des Sciences Naturelles. August, 1846.\nj Supplement to Muller\u2019s Elements of Physiology, by Drs. Baly and Kirkes.\nIn addition to these capillaries, which form a network of channels of irregular calibre, and give off blind branches, some separate irregular corpuscles are seen which are not connected with the vascular network. These bodies send off blind processes, of various forms, in different directions ; in other words, they are stellate cells. They have a reddish-yellow colour, like that of the capillaries of bone, which circumstance alone would be sufficient to make it probable that they are the primary cells of capillaries in process of formation ; and this probability becomes a certainty when we perceive that some of these same stellate cells are already connected with the true capillaries, forming with them a common cavity. This is Schwann\u2019s description. Of its correctness I cannot speak from my own observation, but of the correctness and extreme truthfulness of K\u00f6lliker\u2019s account of the same process in the tails of young batra-chia I can, from my own observations, confidently speak : indeed he has left nothing to be added.\nMorbid Anatomy of Veins.\nVeins are subject to a variety of morbid changes, which are naturally incident to blood vessels of their particular organisation and functions, occasioning a remarkable contrast in their pathology with that of arteries.\nThus veins are much more subject to diffuse inflammation than arteries, and the products of their inflammation being carried in the blood to the heart, are conveyed all over the body ; they moreover offer peculiar facilities for the introduction of morbid materials into the circulation, and from both these circumstances wide-spread and diffuse disease is the result\u2014 conditions which have no parallel as the consequence of arterial disease. Again, an injury to a vein, such as a punctured wound,is followed by cicatrization; and any dilatation of its tube interferes only partially with its functions; whereas in an artery, from the vigorous and pulsating character of the circulation in it, a wound is only to be healed by obliteration of the vessel, and any dilatation of it causes an aneurism \u2014 a progressive and destructive disease.\nFrom the time of Hippocrates, some of the diseases of veins\u2014varix and haemorrhoids \u2014 have been recognised ; but it was not till John Hunter, in 1793, published his paper on the diseases of veins in the \u201c Transactions of a Society for the Improvement of Medical and Chirurgical Knowledge,\u201d that any light was thrown upon that most important of these diseases \u2014phlebitis.\nSince then the subject has received a large share of attention at the hands of some of our most distinguished pathologists : and Hodgson, Travers, Breschet, Bovillaud, Ribers, Ar-nott, Lee, and hosts of others, have all added their quota towards its elucidation.\nThe diseases of veins divide themselves into phlebitis, with which may be considered the effects of ivounds and ligatures; varix and","page":1391},{"file":"p1392.txt","language":"en","ocr_en":"VEIN.\n1392\nh\u0153morrhoids ; rupture ; disease of valves ; phle-bolites ; calcareous degeneration ; fatty tumours ; entozoa.\nPhlebitis. \u2014 Phlebitis may be conveniently divided into plastic and suppurative. They, however, frequently exist together, are produced by the same cause, or give rise to each other.\nVeins possess peculiar facilities for the production of certain of their diseases, especially inflammation of their lining membrane, caused by the introduction of morbid materials into their cavities ; which is a very general cause of the disease now under consideration. They are peculiarly subject to being opened, on account of their superficial position, and their being submitted to the surgical operation of venesection ; and it must be remembered how large a superficies of the venous cavity is exposed at every parturition to the contact of those fluids which are secreted in the healing of the placental wound. The veins situated in the osseous tissues present peculiar facilities for the introduction of morbid matters into the circulation, on account of the patency of their cut extremities, caused by the adhesion of their walls to the unyielding tissue in which they are embedded. Again, the direction ofe th current of the circulation towards the heart, is not likely to expel any materials that are introduced into the vein, but would rather tend to carry them on into the mass of the circulating fluid.\nThe absorbing function of veins is often referred to as a cause of the introduction of morbid matters into the circulation, and this especially as it regards pus, but it cannot be strictly said that pus is absorbed in cases of purulent phlebitis ; and I apprehend that the distinction laid down by Hunter*, on this point, is perfectly correct. It appears to me impossible for any one acquainted with the structure of the coats of blood-vessels, and the anatomy of a pus-cell, to imagine that pus, as such, can be introduced within a vein by any process analogous to absorption. It is true that pus may enter a vein bodily, and as pus; and it is equally true that pus may be absorbed ; but the former is by introduction through some lesion in the vessel\u2019s walls, and in the latter the fluid is in some way altered before it can pass through the tunics of the vein, if, indeed, a vein be here the agent of absorption. When pus is absorbed, as from a bubo, or in empyema, it is attended with a different series of symptoms and consequences from those which arise when it is introduced bodilv, and pus is, in these cases, not to be found in the veins ; and it must be remembered that all the circumstances \u2014 a wound secreting pus and an open vein, or, what is tantamount to the same, such inflammation of a vein as leads to secretion of pus in its cavity, \u2014 are uniformly present where the characteristic results of phlebitis occur. The same thing is imitated by injecting pus into the veins\u2014with like results.\nPlastic phlebitis bears the same relation to\n* On the Blood, p. 360.\nsuppurative, that the two forms of inflammation hold relatively to other organs. Plastic phlebitis indicates a form of disease of milder character, and consummated with results of less severity. Suppurative phlebitis is more or less mixed up with the plastic form, and is generally secondary to it.\nWhen a vein undergoes inflammation, the affected portion throughout its entire thickness becomes of a diffused red, which is not, at this stage, to be distinguished from the red stain produced by contact of the blood, observable, under certain circumstances, in both arteries and veins ; this fades at the edges of the inflamed portion. As the disease advances, the part becomes irregularly mottled of all shades, from purple to the natural colour of the part ; with this appears, in the areolar tissue of the veins, an effusion of sanious serum. The effusion does not end in a serous exudation ; but, as the disease progresses, a plastic effusion is exhibited, not only in the tissue of the vein, but also within its cavity. Whether or not the previously developed serous effusion also escapes in part upon the free surface of the lining membrane of the vein, is not easily determined, but in the stage now under consideration it probably does so, as in other serous inflammation. At all events, at or immediately after the time when such effusion occurs, the tube of the vein becomes blocked up with a coagulum of blood : this does not occur at once, but progressively, beginning by the deposition of fibrine upon the inflamed surface, which deposition is increased by successive layers, the original being for the most part the most compact, until the entire tube is blocked up. That part of this fibrinous product is formed by the serous lining of the veins, \u2014 secreted from the vasa vasorum, \u2014 is proved beyond all question by the experiments of Gendrin and Hope. Gendrin found that, by securing a portion of a vein between two ligatures and removing all the blood it contained, upon injecting some irritating substance into it, plastic lymph was exuded in sufficient quantity to fill the cavity of the insulated portion.* In this experiment the fibrinous matter was clearly true plastic lymph, in all respects similar to the plastic effusion in other serous cavities. Again, the experiments of Dr. Hope, in which, by mechanical irritation, he produced warty excrescences on the valve of the aorta, support the view I have taken. There are many points in the formation of these coagula in veins which are remarkable. That they do, as already stated, consist both of lymph-exudation and coagulated blood is more than probable. But what determines the coagulation of the blood in plastic phlebitis, is less obvious. That the inherent power of coagulation, which the blood in itself possesses, is the cause, is not saying enough. There are\n* The experiments were originally performed upon arteries, but were repeated upon veins with similar results. Dr. Hope\u2019s were upon the aorta near the heart : however, they prove the same fact \u2014 effusion of lymph on the lining of the vascular cavity.","page":1392},{"file":"p1393.txt","language":"en","ocr_en":"VEIN.\t1393\ncertain conditions which must occur before coagulation can develop itself. While the blood, itself in a state of health, remains in. contact with the lining membrane of healthy blood vessels, coagulation is impossible ; but under certain conditions of disease the blood loses its fluidity, and these conditions may either consist in some abnormality of the vessel\u2019s walls, or in some foreign matters becoming mixed with the blood, \u2014 the former influence being passive, and the latter an active agent in producing or hastening coagulation.\nI would here urge the doctrine that the vascular cavity, \u2014the hollows of all the tubular vessels (veins, arteries, and lymphatics), together with the ventricles and auricles of the heart, \u2014 constitutes a true serous shut sac, much complicated in form and modified by its peculiar functions, it is true ; but possessing the same anatomical elements, \u2014 an epithelial pavement placed upon a sheet of limitary tissue, on the other side of which is situated a nutrient vascular system. I would here urge this view, because it applies with much force to certain questions in venous pathology, and to few more so than the one under consideration, where arguments by analogy are a desideratum. The lining membrane of the veins then is a serous membrane. On the surface of other serous membranes \u2014 pleura, pericardium, &c.\u2014plastic effusion consists Of sheets of lymph, and a certain amount of serum. By analogy we, \u00e0 priori, conclude that lymph is effused in inflammation on the lining surface of the veins, and this the experiments of Gendrin and Hope have established by indisputable proof. That the inflammatory product consists partly of serum as well as lymph is supported by analogy alone ; but if admitted would explain the coagulation of the blood to complete the clot, which is known to be so much facilitated by the admixture of foreign or abnormal secretions. Whatever may be the opinion of the formation of the coagulum, its characters are these : \u2014 it consists of concentric laminae, brownish, yellowish, or white, of which the central are the darkest and softest; and sometimes the centre is nearly fluid blood. The density of the entire clot is subject to much variety. The coagulum is moulded to the cavity of the vein, and sometimes present the exact impression of the valves. Mr. Arnott has made an interesting observation with respect to the coagulum, that it extends along the affected vein usually to the next collateral branch, and there abruptly ceases. The true explanation of this circumstance is doubtless that given by Mr. Henry Lee.* \u201c When any portion of a vein is obstructed, the blood is kept at rest between the obstruction and the next collateral branch ; and, if disposed to coagulate, there is nothing to interfere with such an action. But the case is different as soon as one vein opens into another. A fresh current of blood is then continually sweeping the\n* On Phlebitis and Purulent Deposits, by Henry Lee, Lond. 1850, p. 23. vol.\norifice of the obstructed vessel ; and even although the blood at this point should have a tendency to coagulate, it is carried on in the course of the circulation, before it can adhere to the sides of the unobstructed vein.\u201d\nThe coagulum thus extends towards the heart, beyond the limits of the inflamed portion, having a mere mechanical boundary. It extends also at the distal end, but here it becomes gradually attenuated : it often ramifies into many branches and subdivisions of the veins that are tributary to the one obstructed, especially where they are not relieved by collateral anastomoses. At those points where inflammation has not occurred, and the coagulation has been favoured by mechanical circumstances simply, the clot scarcely adheres to the lining membrane of the vein.\nBut the plastic product is not always in the form of a plug, moulded to the cavity of the vein : it sometimes consists of shreds or fringes of lymph, firmly attached to the lining of the vein, and hanging into its cavity, either from the walls or in festoons from the valves.*\nThe walls of the vein, at the same time, undergo change, indicative of the same inflammatory phenomena, which consists mainly in interstitial plastic deposit among the areolar tissue of the tunics.\n\u201c So soon as a fibrinous plug of this description is established, the red and violet speckled colouring abates in intensity, and the internal membrane, losing its smoothness and polish, assumes a dull velvety or slightly puckered appearance. The external membrane appears thickened, turgid, and soon becomes adherent to the cellular tissue, which in its turn has been rendered firmer and paler from the effusion of plastic lymph. Both membranes are still readily distinguishable, and even separable, from each other ; the consistency of their texture is however impaired, and they are easily torn. In this state of things a vein, when cut asunder, does not collapse, even after the plug has been removed ; but, on the contrary, its calibre remains open like that of an artery. This is more than ever the case when the surrounding cellular texture has acquired firmness by the condensation of the inflammatory product infused into it, or when it puts on a brawn-like character, and intimately coalesces with the external membrane of the vessel.-f-\nThese ph\u00e6nomena may occur in veins of any size ; and to any extent in an} particular set of vessels. They occasion obstruction of the circulation in all vessels tributary to the one affected. Of such a condition Phlegmasia alba dolens may be instanced as an example.\nAs regards the cause of plastic phlebitis, or, indeed, of venous inflammation in general, it may be the result either of spontaneous action, or the circulation of poisoned blood\u2014 the latter being infinitely the most common\n* See Cooper and Travers\u2019s Essays, Lond. 1818, part i. plate 10.\nf Hasse\u2019s Pathological Anatomy, Sydenham So \u25a0 ciety\u2019s translation, Lond. 1846, p. 13.\n4 u","page":1393},{"file":"p1394.txt","language":"en","ocr_en":"1394\tVEIN.\ncause. In the latter case the inflammation of the vein is excited by contact of a coagu-lum of vitiated blood with the lining of the vessel. But the veins may, as well as other tissues and organs, be the seat of spontaneous inflammation. This is frequent in some forms of varix ; especially in haemorrhoids, and usually, though not always, leads to the coagulation of the contained blood. I have seen acute inflammation of a varicose saphena causing much interstitial plastic deposit, in which no coaguluin formed in the interior of the vessel, whose canal was quite pervious.\nSuppurative Phlebitis.\u2014When phlebitis leads to suppuration, it is generally, I beheve always, accompanied by plastic effusion also.\nThe question of pus formation within veins is one of great importance and interest, and difficult of solution. In a great proportion of examples, purulent phlebitis is originally lighted up by the mechanical introduction of pus into the veins. In some few cases the pus would seem to originate within the vein, either from an ulceration of the inner surface, or perhaps it is secreted free on the unbroken lining membrane. One very remarkable point is the enormous multiplication of the pus within the vein. No absorption, or mechanical introduction, can at all explain the immense increase ; and it is obvious that there exists within the vessel some source of this pus generation. It was imagined by Gendrin and Donn\u00e9 that the blood itself was the source of the pus, and that it was developed by the metamorphosis of blood globules into pus cells ; and they imagined that the change of form to a sphere, which the blood discs undergo, when submitted to the action of certain fluids, was an indication of the change. This doctrine has, however, been long since exploded.\nA more reasonable explanation, and one founded upon analogy, is that the pus is secreted by the inner surface of the vein, by a metamorphosis of epithelium. Vogel has long since demonstrated, on the mucous membranes, that pus is producible by a change of epithelial cells, and this suggests an explanation, \u2014 why, in an unbroken vessel, pus may be produced in great abundance. Wherever epithelium exists, it appears that pus cells may be generated without lesion of surface; especially where the action is started by contact of pus from some other source. This certainly happens in serous cavities,\u2014pleura, pericardium, &c. ; and we may, from analogy, judge that the same occurs in veins. This doctrine is entertained by the high authority of Hasse : he observes, \u2014 \u201c In accordance with these views, the puriform masses, generated within the veins, would be developed as follows : \u2014 First of all the cells of epithelium-lining discovered by Ilenl\u00e9, separate from the internal membrane of the vein, so as to give the inner surface of the vessel the dull appearance already described, and to render it more susceptible of a morbid tinge from imbibition. The \u2022next change affects the passing blood corpuscles, which assume a spheroid or e.se a\ngibbous appearance, advance with a slow revolving movement, or cling to one another, parting with their serum and with their pigment. The internal membrane of the vessel generates new imperfect epithelium cells, which mingle with the altered blood, and finally actual pus-globules, which, when congregated in sufficient number, completely arrest the current of the blood, and affect the blood-corpuscles in the manner already pointed out. The simultaneous effusion of both fibrin and albumen now serves to complete the formation of a plug, which differs in external characters according to its more or less rapid development, and to the varying proportions of its constituent parts. The plug, thus originating, afterwards undergoes further changes.\u201d *\nThe actual changes that occur, and are obvious to the naked eye, aflect the plastic plug, the fluid contents, and the parietes of the vein. In suppurative as well as adhesive phlebitis, plugs of lymph and coagula are formed, and are partly the result of inflammatory action, and partly they are the direct result of the contact of fluid pus with the blood.f\nThe plugs that form in suppurative phlebitis are softer, more numerous, and vary in form. They soon become broken down, and exhibit disintegrated fibrin mixed with genuine pus. The coagula become softened, first in the centre ; they loose their laminated structure, and ultimately break up. These coagula, in phlebitis the result of infected blood, must not be considered as any indication of the locality in which the disease has originated. In such cases the whole circulating mass is infected : little portions of coagulating fibrin, entangling pus-cells, are continually passing through the vessels, and here and there attaching themselves to the lining of the vessel, light up circumscribed regions of inflammation. This coagulation is a remedial effort : by its means the materies morbi is shut up and circumscribed by a harmless coagulum : circulation in the affected vessel is suspended and the poison cannot again mix with the blood. Perhaps these coagula sometimes become absorbed, or organised and obliterate the vessel ; at other times they suppurate, and the walls of the vessel become implicated and ultimately give way. \u201c The formation of matter being brought about within the inflamed vein, its membranes have likewise to undergo a further change. Their colour now inclines to a greyish white ; they become softened and thickened, are no longer to be distinguished from one another, and form, in conjunction with the surrounding textures, a nearly uniform membranous layer of\n* Hasse\u2019s Pathological Anatomy, p. 16.\nf The influence of pus in causing coagulation of the blood may be seen in the following experiment : \u2014 \u201cAn abscess was opened in the groin, and a quantity of pus received into a gallipot ; some blood from the divided vessels was also received into the same vessel ; they were then stirred together, and in two minutes the mass coagulated. Some blood taken from the same patient in the same manner, but not mixed with pus, coagulated in eleven and a half inimit\u00e9s\u201d\u2014Lee on Phlebitis, &c. p. 27.","page":1394},{"file":"p1395.txt","language":"en","ocr_en":"VEIN.\t1395\na lardaceous aspect and character. By and by a turbid puriform fluid is often found deposited at intervals in the cellular texture ; in some instances where the suppuration is vigorous in the vicinity of the vein, the latter traverses the purulent channel for a considerable space, denuded of its entire circumference. Here the membranes of the vein gradually soften, and at length melt down, so to speak, until no further vestige of their texture is discernible within the common centre of suppuration.\u201d* If, however, this circumscription of the pus by means of coagulum does not occur, and it floats through the vascular system, it produces a variety of secondary effects remarkable and important in their results.\nThe products of this secondary action are known as \u201c purulent deposits\u201d or \u201clobular abscesses.\u201d Strictly speaking, they are not deposits of pus; but the pus is \u201ctranslated\u201d from one part to another, and there becomes the originator and centre of a fresh abscess.\nThe actual mode of production of these lobular abscesses has been the subject of much discussion ; but the evidence upon the various points appears to resolve itself into the following explanation. The pus-cells being bodily introduced into a vein, or generated in it, pass forward in the circulation till arrested in the capillaries by their size being too great to admit of their passage : they then excite inflammation of the parenchyma of the affected organ, which leads to condensation, and, subsequently, to suppuration : the pus-cells being the excitants of the inflammation, which is suppurative, not only from its intensity, but from the fact that pus germs are furnished by the same body as originates the inflammation, and thus more pus is generated.\nThe appearances of these local abscesses, which are, strictly speaking, foreign to our present subject, are determined by the character of the organ in which they occur.\nThere appears to be some general laws as it respects the development of these abscesses. They occur in those organs which are most vascular, and through which the largest quantity of blood passes in the smallest space of time; thus the lungs and liver are affected the most abundantly. Again, after the blood has been infected and the pus added to it, that system of capillaries is first affected, through which the fluid first passes; the capillaries, as it were, filtering off the pus-cells and retaining them. Thus, if pus gets into the systemic veins, the capillaries of the lungs will be the first to arrest their progress ; and when this happens, as is generally the case, lobular abscesses are most abundantly, or exclusively, found in those organs, and when found elsewhere also are most advanced in the lungs : when, however, the portal system is the vehicle of the pus, as occasionally happens after operations on the rectum, for example, we find the abscesses in the liver. These laws are quite correct in the main ; but there are some exceptions to them, and these exceptions are\n* Hasse,, loc. cit. p. 18.\nquite explicable ; for though pus-cells are for the most part too large to pass capillaries, especially with their tendency to coagulate blood, they may nevertheless pass through some of the larger ones ; and it must be admitted that disintegrated pus globules may pass through the smallest vessels : hence, in some instances, the laws here suggested are not exemplified.\nThe results of phlebitis are either suppuration, resolution, or obstruction, the consequence of organisation of the effused lymph. Upon the latter subject some observations are necessary.\nObliteration of Veins.\u2014Obliteration of veins, the result of phlebitis, may be either incomplete or complete. Hasse mentions two forms of partial obliteration of veins ; the first of which has also been described by Carswell. This form consists of a thickened and turgid condition of the vessel\u2019s w7alls, as if they had been macerated ; at the same time they are closely connected with the surrounding areolar tissue. Within the vein, and intimately connected with the lining membrane, is a hollow cylinder of fibrin, firm and whitish on its exterior, and soft and dark-coloured within ; the interior being bathed with the circulating blood. Dr. Carswell\u2019s explanation of this, in which Hasse coincides, is that the soft centre of the plug is carried away before the circulating current, whilst the exterior becomes organised and united with the interior of the vein.\nIn the other form he describes the vein as reduced to a whitish cord, and filled with an organised plug. \u201c Betwixt this plug and the thickened coats of the vessel, round about the periphery of the former, were several little canals, which, running along the whole extent of the vein, had already begun to re-establish the circulation. In all probability the impulse of the blood below had, during the first period of inflammation, here and there severed the plastic plug from the parietes of the vessel ; subsequently, the above plug being organised, and the intervening blood absorbed, several peripheral channels would form, instead of a single central one.\u201d *\nIn complete obliteration the vein diminishes in size, shrinks nearly to a cord, and becomes pale and soft. The plug also becomes reduced in size and organised, and adheres firmly to the lining of the vein. How the plug receives its vessels and communicates with the vasa vasorum of the vein, I am not prepared to state. But fibrin thus isolated probably has the inherent power of generating vessels, which ultimately communicate with those of neighbouring textures. The secondary consequences of obliteration of veins, \u2014 oedema, Phlegmasia dolens, &c. cannot here be considered.\nHealing of Wounds in Veins. \u2014 The condition of the wound and its mode of healing depend upon the character and direction of the\n* Hasse, loc. cit. p. 26. I beg to make abundant acknowledgments to the very valuable writings of this author, from whom I have drawn largely.\n4 u 2","page":1395},{"file":"p1396.txt","language":"en","ocr_en":"1396\nVEIN,\nwound. If the wound be linear, and made in the axis of the vessel or somewhat obliquely, and there be not- much bleeding, its lips will come together, adhere, and rapidly form a linear cicatrix. If, however, it be transverse, or if much bleeding occur from it, a coagulum will form in and over the aperture. \u201c An oval naked coagulum forms the plug of the orifice, and a flattened covered clot, which is an extravasation into the cellular sheath, extends to some distance around it.\u201d* In twenty-four hours the lips of the wound are found separated, the edges are everted and adhere to the clot. At the expiration of three days the internal margin of the wound is elevated and rounded, and a thin, narrow, membranous expansion, partially extending over the inner surface of the clot, is seen to be continuous with the everted edge of the internal tunic. The clot is more compact and lamellated. At the fifth day the membranous appearance extends over the whole inner surface of the clot. Subsequently the clot becomes more and more absorbed, and the new membrane, extending from the lips of the wound, becomes more organised. Vasa vasorum can be seen on it by means of a lens from the twelfth to the sixteenth day. \u201c On the twentieth day it is only possible to distinguish the recent from former wounds, by the tenuity, smoothness, and transparency of the new membrane compared with the old, which is dense, tough, and wrinkled.\u201d These dates, &c. refer to the wounds made in ordinary bleeding operations; in larger wounds the process is proportionately longer. The wound is ever after indicated by the peculiar thin, transparent, extensile membrane with which it was repaired, If a vein, having one of these cicatrices in it, be injected with water, the new membrane bulges out, on account of its elasticity, into a pouch or bag.-f- Mr. Travers is quite convinced that this new membrane is continuous with the internal membrane of the vein.\nEffects of Ligatures on Veins.\u2014 The effects of ligatures on veins are different from those on arteries. The coats of the vein are, by the ligature, thrown into longitudinal folds, which are indicated when the vessel is slit up, and its interior examined. The effect on the elementary coats of the veins is different from that produced by ligature on the arteries : instead of the deep cut through the inner and middle coat, which occurs in the latter, there is but a slight indentation, corresponding to the ligature on the vein. This is produced by the lesion of the thin internal tunic, and that alone. As regards the rest of the thickness of the vein\u2019s walls, it appears that the outer or cellular tunic is divided, leaving the middle condensed portion of the venous wall uninjured. Upon a close examination, however, it is found that one element\u2014namely, the yellow elastic tissue \u2014 is divided throughout the entire thick-\n* Travers, loc. cit. p. 246.\nf See the beautiful plates accompanying Mr. Travers\u2019s essays before referred to.\nness of the outer and middle coats, leaving the continuity of tube to be maintained by the white fibrous element, which does not suffer division ; and therefore that part of the wall where the white fibrous element is most condensed and abundant is that where least impression is made by the ligature. A thin, tightly tied, string produces the deepest impression.\nAccording to Mr Travers, when a ligatu re has been applied for a period of from twenty-four hours to five days, it has produced the following changes :\u2014 \u201c The vein above and below is thrown into longitudinal folds on either side of the ligature. The portion next the heart is perfectly empty and collapsed ; that next the extremity is filled to distension by a long, and, generally, firm, coagulum of blood, which is a mould of the vessel, and bears the impression of its semilunar valves. The coagulum extends for several inches ; it is not always compact and lamellated, and adhering to the internal tunic, being sometimes less consistent and broken; but it always fills the calibre of the vein. There is no blush upon the internal tunic, much less any sign of adhesive inflammation, or thickening of the proper coats of the vein, or agglutination of its contiguous folds ; these folds being effaced on the removal of the ligature ; but the cellular sheath is thickened by a deposit of lymph in the vicinity of the ligature.\u201d * If two ligatures be applied, and the vessel divided between them, the ends retract about an inch. At the seventh day the interstitial deposit of lymph among the areolar tissue around the vein is very dense, and forms a hard fibrinous mass, through which the ligature runs in a sort of canal. According to Mr. Travers, ulceration commences on the ninth day, and lasts from fifteen to twenty-five days. \u201c The ulcerated ends of the vein formed a crescentic sweep, and were separated to the extent of an inch, and fastened by adhesion to the cellular sheath, which was much extended and thickened by a subjacent deposition of lymph, so as to form a smooth solid bed between the divided ends of the vein. The internal membrane of the superior portion of the vein had a thin ragged edge, where it had been severed by ulcerationr The lower edge was smooth and blended in with the bed of the wound. The extremities had undergone no contraction but that produced by the adhesion of the severed extremity to the sheath. The portion of the vein next the heart was empty. The upper f was filled by a dark lamellated coagulum of blood, adhering very strictly to the internal tunic, which was discoloured by it. On carefully separating the outer lamell\u00e6 which coated the interior of the vein, I could not discover any thickening of the proper coats of the vein, nor any appearance of inflammatory action within its canal, nor was any such appearance indicated in the lower portion of the vein.J\n* Travers, loc. cit. p. 252.\nf The jugular vein is referred to.\nI Travers, loc. cit. p. 253.","page":1396},{"file":"p1397.txt","language":"en","ocr_en":"VEIN.\t1397\nPhlebectesis \u2014 Varix. \u2014 Dilatation of veins is not only the commonest morbid change in veins, but is the most frequent single pathological condition that occurs in the human body.\nVarix is a condition of vein which occurs in every possible variety of degree, and in various localities, and is generally developed by the superaddition of some mechanical exciting cause upon a constitutional predisposition, \u2014 by the operation of some local physical influence upon veins, which, in common with the other veins of the body, already possessed an abnormal laxity or softness of texture that favours their dilatation.\nThe structure of veins, already described, pre-eminently favours their dilatation: \u2014 a structure consisting almost solely of longitudinal fibres, with comparatively few in a circular direction to brace up its calibre, presents little to restrain its dilatation beyond the lateral adhesion of the contiguous fibrous rods and their matting together by a certain amount of lateral branching. The coats of veins moreover are very thin, and the amount of distending force applied to them often very considerable.\nThe anatomical relations of certain veins give them, when in a state of varix, considerable peculiarities, and various distinctive appellations have been conferred upon such local affections, \u2014 varicocele, h\u0153morrhoids, &c. : their pathological identity is, however, indisputable.\nThough varicosity of the veins is, for the most part, confined, in one individual, principally to one locality, it nevertheless appears to depend upon a vice pervading the entire venous system, the effects of which are more particularly called out in one locality by the existence of some mechanical excitant there present. I cannot at all agree with Hasse and Landouzy, \u201c that the full development of this disposition in one locality prevents its outbreak in another.\u201d This doctrine has, however, been supported by a show of argument. Thus it may be truly said that haemorrhoids, varicocele, and varicose subcutaneous veins very seldom exist together in the same individual : the concurrence of either two of them is unusual, and much less frequent than their solitary development ; and moreover the different forms are met with, as a rule, in different elasses of society : \u2014 thus haemorrhoids are most frequent in the affluent, varicocele in the sensual, and varix of the lower extremities in the labouring classes. Again, the different forms appear at different periods of life, \u2014\u25a0 varicocele about or soon after puberty; haemorrhoids and other varix usually about manhood. But all these arguments fail, when it is recollected that in each of these suggested instances there is some special circumstance, which, acting as an excitant, superadded to a previous constitutional disposition, might account for the particular locality in which the disease makes its appearance, and the particular time at which it occurs. If in all these instances obstruction to the circulation cannot be made out, there is some cause of greater\nvascular activity, which is also seen to be efficient in the production of phlebectesis. H\u0153morrhoids are most frequent in the affluent, because their mode of life leads to greater vascular activity in the alimentary canal, and to frequent portal obstruction : varicocele in the sensual, from the greater stress of blood upon the spermatic veins at puberty also, from the same cause : the labouring classes likewise are afflicted with saphenous varix on grounds similarly explicable. It is because there is particular emphasis laid on one particular organ in each of these cases that the specific form of phlebectesis is assumed in the separate examples. And where such influences have been compound, other effects have followed, combining more or fewer forms of varix. It cannot therefore be said that one form of phlebectesis prevents another, or even diminishes the chance of its formation ; the truth is, that the same individual is not liable to be exposed to the exciting cause of more than one form, \u2014 that the predisposing condition of the veins may be universal, but in one set alone is the morbid change called forth.*\nPhlebectesis may conveniently be divided into several forms. Andral has made the following division : \u2014\n\u201c First species. Simple dilatation, unattended by any other alteration, either affecting the whole length of the vein, or existing only at intervals.\n\u201c Second species. Dilatation of the veins, either uniform or at intervals, with thinning of the parietes at the dilated points.\n\u201c Third species. Uniform dilatation of the veins with increased thickness of the parietes.\n\u201c Fourth species. Dilatation of the veins at intervals with thickening of the parietes at the points where the dilatations exist.\n\u201c In these two latter species, the vessel increases in length as well as in breadth, and in consequence becomes quite tortuous in its course.\n\u201c Fifth species. Dilatation of the veins, with the development of septa or partitions, which divide the interior of the vessel into small compartments, that allow the blood to stagnate or to coagulate, &e.\n\u201c Sixth species. Dilatation of the vein, its interior being divided into a number of separate compartments, as in the preceding species, and in addition its parietes drilled by a number of minute holes, which allow the blood to pass from the vein into the surrounding cel-* lular tissue,\u201d &c.\nThese include all the forms of phlebectesis as far as systematic division is concerned.\n* This may be very pointedly illustrated by instancing the two spermatic veins in varicocele respectively. It cannot be said that varix of the left prevents varix of the right spermatic vein; for both, not unfrequently,. occur together. It cannot be said that there is any difference in structure or constitution between the two veins in the same individual. Then, why should the left, and the left alone, be, in nine out of ten cases, affected ? Simply because a strong mechanical influence operates on one and not on the other vein.\n4 u 3","page":1397},{"file":"p1398.txt","language":"en","ocr_en":"VEIN.\n1398\nThe first species simply includes a general predominance of the venous system,\u2014 a disproportionate size of the veins. It is of very frequent occurrence, and is indicated by a plethora or distinctness of the veins of the subcutaneous system. This is often seen in the veins of the back of the hand. It is not to be considered strictly morbid, \u2014 it is in many individuals an original conformation, and in others merely temporary, the result of warmth, strong exercise, pressure on a venous trunk, &c. It is common, nay general, in old people, though the healthiest. It may be here observed that the capacity of veins, as well as that of arteries, increases with age.\nThe second species represents a condition unquestionably morbid. It consists in a dilatation of the vein at the expense of its walls, they becoming attenuated in proportion to the increase of the vessel\u2019s calibre. This appears to consist essentially in a separating of the longitudinal fibres of the outer coat, by which the internal membrane is permitted to dilate or protrude. The dilatation is seldom cylindrical, it is usually unequal and in pouches. These pouches are usually more or less globular or oval ; sometimes, however, they are constricted, or form pear-shaped, or even pedunculated, tumours.\nThe third and fourth species of Andral\u2019s division are modifications of the same condition, and seem to be in many cases the direct but gradual result of the first. Whether the dilatation be general and equable, or partial and irregular, the thickening is confined to the dilated portion, and is doubtless a reparative condition, \u2014 an effort to resist by increased strength of the vessel\u2019s walls any further stretching ; and it may be observed that in this thickened form of phlebec-tesis, those large, pouchy, and tumour-like, dilatations do not occur. In these forms the dilatation is more regular and cylindrical, or increasing somewhat evenly in passing from one part of the vein to another. In almost all these cases there is increased length, sometimes very considerable, so as to make the vein assume a serpentine or tortuous course ; in some instances the vein remains perfectly straight. The increased thickness arises from the superaddition of fibrous tissue in the external coat, probably developed from a sub-inflammatory plastic exudation among the normal tissue of the outer coat, itself an effect of the stretching, in the dilatation of the vein. The amount of thickening varies in different cases : in those fully formed it is often very considerable. The increased thickness of the vessel\u2019s walls prevents it from collapsing when cut through : it remains patent like an artery. The colour of its tissue differs, however, from the arterial; it is reddish white, and pale,like the normal venous tissue. Besides thickening of the coats of the veins, they become indefinite and very hard ; the outer coat becomes completely blended with the.areolar tissue of the sheath of the vessels ; by this means the walls, which are often thicker than those of\nan artery of the same size, are with difficulty pressed together.\nAs regards the fifth species, I agree with Hasse, that it more deserves to be considered as a mere variety of the others than as itself distinct. Tke septa are probably not new formations.\nThe sixth species, whilst it evidently refers to a particular form of venous dilatation, is obviously misdescribed ; the minute holes \u201c drilled in the sides of the veins\u201d in this species being in reality nothing more than the mouths of small and dilated veins, whose dilated and attenuated walls are not easily recognised, and thus the blood is thought to escape into the cellular tissue.\nTo these may be added certain varieties of erectile tumour, which consists essentially of modified capillaries, but on which the venous character is conspicuously impressed. In these cases there are oval or spheroidal tumours of a bluish or purple colour. They are composed of dilated capillary veins, which are supplied by enlarged arteries. The veins are stretched into saccules and crypts, and the blood is removed from them in veins disproportioned to the size of the affected part, and often themselves varicose.\nHaving considered phlebectesis in general, I may conveniently devote some remarks to a few of the special forms of varix.\nVarices of the Leg. \u2014 Varices of the lower extremity usually occur after the commencement of adult life. They are generally the result of habitual toil in the erect posture; they result also from obstruction to the circulation ; and a not unfrequent source of obstruction has of late been displayed in the fascia lata that forms the saphenous opening. Briquet has shown that this affection is more common amongst males than females. In 258 males examined by him 71 had varix of the leg ; in 485 females, 42 were affected.\nThere is another distinction in the disease as it appears in the two sexes ; in man one trunk is usually affected, or, at all events, the disease is confined to vessels of larger size; whereas in the female, the smaller cutaneous twigs are generally the subject of the disease, and then present an elaborate series of purple ramifications, very superficial and distinct ; and often associated with the latter are circumscribed local varices of greater size. This is the general rule, but it is liable to exceptions ; each form may occur in either sex, but the latter is almost always confined to the female. This circumstance was, I believe, first pointed out by Hasse.\nIt is unusual for all the veins of the leg to become varicose ; it is usually confined to one branch of the internal saphena : the external saphena may however likewise be affected, or several branches of each. It is uncommon for them to be affected symmetrically ; the right leg, according to Briquet, is most generally the subject of varix.\nVarices of the leg are arranged in various forms : in some cases they consist of packets of folded and reduplicated tubes, which, not a","page":1398},{"file":"p1399.txt","language":"en","ocr_en":"VEIN.\t1399\nlittle, resemble, when seen through the skin, the vesicul\u00e6 s\u00e9minales ; in other examples the varix is single, straight and prolonged. A remarkable instance of this occurred under the observation of the author not long since ; it consisted in a varicose condition of the internal saphena on one side alone: the vessel formed one large, straight, uniform cylinder from the saphenous opening to the inside of the foot, measuring about two thirds of an inch in diameter.\nPhlebitis often occurs in varix of the leg. The valves moreover are subject to peculiar malposition, dependent upon the distension of the vessel\u2019s tube : these conditions are noticed elsewhere.\nVaricocele, or varicose dilatation of the spermatic veins is another peculiar form of phle-bectesis. In its general anatomy it differs in no respect from the other forms of varix.\nVaricocele appears to be dependent upon sexual development, and occurs principally about puberty. Landouzy has demonstrated this as follows : \u2014\n(13 occurred between 9 & 15 yrs. of age. In 41 cases20\t\u201e 15 & 25 \u201e\n(.3\t\u201e 25 & 35 \u201e\nThe\tinfluence\tof mechanical pressure\tin\ncausing this malady is very strikingly shown by the fact that the disease is almost confined to the left side, on account of the long and uninterrupted current of blood which bears upon the left vein, by means of the high juncture of the spermatic vein of that side with the renal vein. Breschet found in 120 cases but one on the right side.\nHcemorrhoids, in their relation to phlebecte-sis, consist merely of dilated veins, situated in the vicinity of the anus, and in which chronic inflammation and thickening of the external coat and surrounding areolar tissue is very conspicuous. The dense covering of areolar tissue, and the comparative smallness of the enclosed vessel\u2019s calibre, have given rise to different explanations of the pathological origin of piles.\nLe Dran, Racamier, Delaroque, Cullen, Chaussier, and others have considered them as encysted coagula of extravasated blood. Delpech and Cruveilhier describe them as tumours of erectile tissue. But by far the most numerous and reputed pathologists, among whom may be mentioned Andral, Stahl, Petit, Morgagni, Hodgson, Lobstein, Froriep, and Brodie, concur in the now generally received doctrine of the origin of haemorrhoids in varicose veins.\nHaemorrhoids consist of oval, ovoid, or round masses with broad bases, situated either just within, or just without, the sphincter ani. On examining the texture of these tumours, they are found to consist of cells or cavities of various sizes, surrounded by layers of red, dense, areolar tissue. These, which vary in shape, are lined internally by the smooth lining membrane of the vein, and are perforated here and there with the apertures of small communicating and tributary veins.\nThe absolute 'continuity of these cells with the venous cavity has been proved by Hasse and Brodie, who have injected them from the arteries ; the former has also injected them by the veins.\nThey are very apt to inflame and become lined with lymph, or stuffed with coagula.\nVarices occur in all situations and in every variety : instances are on record where they have occurred in the veins of the oesophagus, lips, eyelids, bladder, heart, &c. : indeed there appears to be no region which is free from the occasional development of this disease.\nRupture or Perforation of Veins. \u2014 A number of pathological examples, in which perforation of the vessel\u2019s walls is the conspicuous character, may be conveniently, though, it must be confessed, not very naturally, classed under this head. Either with or without previous change, and that change very various, the lesion may occur, so that the only condition common to these instances of morbid change is a breach in the venous cylinder.\nA rupture, without previous morbid change in the vessel, and which may occur in any case where the tissues of the vein are thin and weak, may be produced by an unusual amount of internal tension of the contained fluid. So again, an attenuated or ulcerated state of vein may yield bbfore an amount of distension that is neither excessive nor unusual : rupture is the result in either case.\nDestructive disease may, as well in veins as elsewhere, attack the tissues of the organs in question, \u2014 suppurative inflammation, ulceration both extrinsic and intrinsic, extension of malignant disease, &c. : perforation is here the issue.\nIn the rupture of a previously healthy vein the change consists in a rent or tear of the structure, the surrounding tissues being normal : the rent is sharp, and more or less regular. In perforation from ulceration, &c. the aperture is rough, irregular, and jagged ; the parietes of the vesselare thinned down towards the hole, are much thickened more remotely, and the orifice is ragged and shreddy.\nSudden or extreme obstruction to the circulation, thus causing excessive distension, has produced rupture of the healthy veins. Bichat mentions instances of rupture of the veins of the lower extremities during pregnancy ; Lee, those of the labia during labour. Violent muscular exertion has ruptured veins, by producing local congestions : Hodgson, for example, has witnessed rupture of the veins of the leg during cramp of the gastrocnemius ; I have three times seen rupture of a vein on the dorsum of the foot during strong exertion. Andral narrates an example where, during a violent struggle, the vena cava inferior was ruptured ; \u201c the borders of the perforation seemed as if they had been torn asunder, and the coats of the vein in the neighbourhood were perfectly healthy.\u201d The peculiar bloodlessness of the surface, and consequent deep-seated congestion which occurs during rigors or the sudden application of cold\n4 u 4","page":1399},{"file":"p1400.txt","language":"en","ocr_en":"1400\nVEIN.\nto the surface, has ruptured the large internal veins. Portal tells us of a case of rupture of the vena cava superior from a patient getting into a cold bath: and Senac mentions the rupture of the large internal veins as occurring in the rigors of intermittents.\nRupture of the inferior cava from disease, has been described by Dr. Squibb, in the Philadelphia Medical Examiner for 1847.\t\u201c The\nvein at this point had been very much dilated, and its coats much diseased and thinned : a semiorganized mass or clot, which was contained in the dilatation, was connected by its surface to the softened coats of the expanded vessel, and the rupture had occurred at the junction of the edge of this mass with the side of the vessel, and not at the projecting point of the dilatation. The tumour was on the anterior portion of the circumference of the vessel, and was overlapped by the edge of the liver, and by a portion of the stomach.\u201d\nMorgagni mentions the rupture of a varicose azygos vein, the result of extreme varicosity. Perforation of veins from suppurative inflammation or ulceration is not uncommon. The cavities of the veins, especially in the stomach and uterus, are often laid open by the extension of malignant disease. But the commonest form of venous perforation is from the tegumentary varicose ulcers of the leg, which is originally extrinsic to the vein.\nThe following enumeration of ruptured or perforated veins is from Andral. \u201c It has been seen, first, in the superior cava, both within and without the pericardium ; second, in the inferior cava ; third, in the vena port\u00e6, both within and without the liver ; fourth, in the splenic vein ; fifth, in the jugular vein ; sixth, in the subclavian vein ; seventh, in the veins of the extremities ; eighth, in the veins that run between the coats of the intestines.\u201d\nAffections of the Valves of Veins are partly mechanical and partly dynamical. The most frequent change they suffer from is the result of the distension of the vein in which they are placed ; but they are occasionally the subject of the same changes as occur in the vessel itself. In varix the valves are not necessarily damaged, though from the increased size of the vessel in which they are placed they are disproportioned to their office, and become useless. Instances are mentioned by Stanley, Langstaff, and Dr. R. Lee, where the valves in varix were quite healthy,_ thin, and transparent, but drawn aside and inadequate to cross the vessel\u2019s tube. The usual result of varix is to injure the valves : they then become tom in shreds or perforated ; or the attached margin becomes detached, and the valve is reduced to a membranous thread, which stretches across the diameter of the vessel. In other instances the valves are rendered opaque and thick,\u2014 the result of chronic inflammation. Whenever any affection of the valves occurs, they are apt to become coated with lymph ; and when a vein is the seat of plastic inflammation, the valves usually become ragged fringes of lymph.\nPhlebolites. \u2014 The curious bodies called phlebolites, pklebolithes, or veinstones, which have excited much interest in the pathology of veins, are true vascular calculi, \u2014 are calculi or earthy concretions deposited from the blood in the veins ; and though their mode of formation differs considerably from those other bodies which form in other hollow organs, and which we call calculi, they are still quite as much entitled etymologically to the same designation.\nAt a very early date, among the writings of Realdus, Columbus, and Bartholin, phlebolites were recognised and described ; but it was not until Otto, Tiedemann, Cruveilhier, and Carswell devoted their attention to them that they excited much interest. Matured phlebolites are, for the most part, oval or roundish bodies, sometimes irregular and flattened ; they are sometimes prolonged and much attenuated at one extremity, corresponding to the distal end of the vein in which they are embedded. They vary much in size, from a grain of millet seed to a pea, or even to a hazel nut ; their form also differs. Dr. Lee describes a cylindrical vein stone, which was found in the right common iliac vein of the late Lord Liverpool ; it was an inch or more in length.\nThese concretions are of a yellowish or white colour ; they are of varying density, being sometimes of bony hardness, and at others much softer, with a firmer nucleus, which is always harder than the other parts of the stone. When sections are made the cut surface presents a series of concentric rings, \u2014 there being at different distances from the centre sufficient change of colour and density to mark each annulus ; so that the calculus is thus seen to be composed of successive concentric laminae, hardest in the centre, and gradually becoming softer in proceeding outwards. They are frequently seen surrounded externally by a layer of plastic material, looking like a membranous investment ; at other times they are firmly imbedded in a dense coagulum ; but in the majority of instances they are free from any covering. The hardest stones, however, contain, intermixed with the calcareous matter, much soft animal material ; for, when desiccated, they diminish in size ; and, unless the layers have received equal proportions of earthy deposit, they become irregular.\nPhlebolites have been made the subject of chemical analysis. According to Gmelin, the following is their composition : \u2014\nAnimal matter\t-\t27*5\nPhosphate of lime\t-\t53\u20185\nCarbonate of lime\t-\t]5'5\nMagnesia and loss\t3-5\n100-\nThis analysis has been repeated with the same general results by Prout, Kemp, Hasse, and Lehmann. They have since been submitted to another analysis by Schlossberger,","page":1400},{"file":"p1401.txt","language":"en","ocr_en":"VEIN.\nnot\nwho has given his results more in detail, as follows : \u2014\nPhosphate of lime\t-\t50-1\nPhosphate of magnesia\t-\t13-7\nCarbonate of lime\t8-3\nOrganic matter\t-\t20-4\nWater\t6-1\nLoss\t-\t];4\n\t100-\nThese, then, are phlebolites completely matured. In those less completely developed the phlebolite consists of an altered coagulum, in the centre of which is earthy matter, surrounded by white fibrinous concentric layers. Cloquet has described one, which was not fully formed, in which the calcification was incomplete. It was taken from the inferior cava, and consisted of a fibrinous mass, containing a calcareous centre, from which a number of rays of the same substance passed through the fibrinous matter toward the circumference. Cloquet describes one of similar structure, which he saw in S\u0153mmering\u2019s museum, and which was also taken from the inferior Cava. In a still more primitive condition these calculi are recognisable. \u201c On drying the coagula found within dilated veins, previously to their having coalesced with the internal membrane, they shrink together, grate under the knife, and exhibit calcareous induration at certain points, even in cases where it had not been at all suspected.\u201d *\nAs regards the origin and development of phlebolites, only one opinion is now entertained, namely, that they are developed from modified coagula. Andral, however, gives the following explanation. After speaking of calcareous degeneration of the coats of veins, he goes on to say, \u201c these calcareous concretion\u00ab, instead of lying between the coats of the veins, sometimes push the internal membrane before them, and project into the interior of the vessel; the m\u00ebTnbrane in such cases generally contracts behind the concretion, and forms a peduncle, which serves to attach it to the side of the vein. It is probable that these peduncles are sometimes ruptured or absorbed, and thus the concretion is completely detached from its connection, and drops loose into the vessel. This rationale may serve to explain the origin of some of those calcareous concretions which have been found in the centre of the venous coagula, j-\nHodgson imagined that phlebolites were formed in the neighbouring textures, and found their way into the veins by progressive absorption.\nDr. Carswell has described and illustrated the true method of their formation in detail, exhibiting their successive changes in the progress of maturation. At first a coagulum of blood is formed, which becomes condensed and laminated in the centre ; the colouring matter of the blood subsequently becomes ab-\n* Hasse\u2019s Pathological Anatomy.\nf Andral, Precis, d\u2019Anatom. Pathol, tom. ii.\nsorbed, and leaves ordinary yellow fibrin ; this also becomes lamellated throughout. After this calcification commences in the centre and proceeds outwards till the whole is calcareous.\nThis mode of formation is maintained also by Otto, Tiedemann, Lobstein, Cruveilhier. Errhman, Briquet, and Hasse.\nThe position of the phlebolite within the vein, and the condition of the vein and phlebolite respectively, are subject to much variety.\nIn the dilated pouches, which sometimes form in the sides of the veins, coagula are frequently produced, which may terminate in phlebolites. The pouch being filled, the walls become atrophied, the inner surface becomes l\u2019ough and cellular, and closes firmly round the calculus, sometimes making it appear external to the vein. At other times, not only the pouch, but the. entire calibre of the vein, becomes implicated and stuffed with calcifying coagulum ; in this case a portion of the tube becomes obliterated. In other instances the phlebolice is free in the cavity of the vein, is loose and movable, and the vessel that contains it is still permeable to the circulating current. Such phlebolites, though loose and movable, are frequently surrounded by coagula of blood ; sometimes by a layer of fibrin. They have occasionally been surrounded by a thin layer of fibrin, and attached at one point to the side of the vein by a sort of peduncle, the rest of the body hanging free into the cavity of the vessel Tiedemann very naturally suggests that in these cases the peduncle is produced by the effusion of coagulable lymph, the result of inflammation, caused by the presence of a foreign body.\nPhlebolites have been discovered in very many of the veins : they have been found in the vena cava inferior, the renal, the dorsal, the common iliac, anterior and posterior tibial, the saphena and other superficial veins of the lower extremities, the hypogastric veins ; also in the uterine, the vaginal, spermatic, vesical, prostatic, and h\u00e6morrhoidal, veins. They have likewise been seen in the splenic and mesenteric veins. Their most frequent and most abundant position is in the veins of the pelvic viscera. In number they vary considerably : there are generali}', though not always, more than one. Tiedemann found thirty-six in the spermatic veins of one individual,\u2014fifteen in one, and twenty-one in the other.\nThey occur almost always after middle age. They produce no injury or inconvenience ; nor is their presence known, except in a few situations, during the life of the individual.\nThere are some general circumstances relative to phlebolites which are striking and curious. They always occur in veins below the diaphragm, \u2014 in depending veins, \u2014 in veins which circulate their blood against the force of gravity.\nAccording to Hasse, they always occur in conjunction with phlebectesis.\nThey frequently, perhaps generally, occur in veins returning the blood from diseased organs, \u2014 from a diseased testicle or prostate, from an ulcerated rectum, from an inflamed or","page":1401},{"file":"p1402.txt","language":"en","ocr_en":"VEIN.\n1-402\ncancerous uterus, from an ulcerated leg, &c. Examples of all these are on record.\nWhat, then, determines their development? Tliis question it is not easy to answer ; all we can say is, that those circumstances which facilitate mechanically the coagulation of the blood, favour their production ; and it is not improbable also that a vitiated state of blood may predispose to and favour their development : it is certainly probable that the predisposing causes, whatever they are, may be started into activity and be made efficient for the production of these bodies, by some temporary local disturbance of the circulation, or by some slight subinflamtnatory condition, which varicose veins readily take on, and which, were it not for the existence of predisposing circumstances, would soon be resolved.\nCalcareous Degeneration of Veins. \u2014 The transformation of the walls of veins into earthy tubes, or calcareous deposition among their \"tissues, is infinitely less common than in arteries. It still however does occur, and apparently in the same manner, by the sanm progressive changes, and from the existence of the same constitutional tendency, only in circumstances of greater intensity.\nOccasionally patches of atheromatous deposit \u2014 consisting, as in arteries, of choles-terine, oil, and phosphate of lime, \u2014 are seen on the inner surface of veins, though they are always much smaller, and less general than those which are found in the arteries of the same individual. They present a white opaque appearance, and produce a slight elevation of the surface where they are situate. This deposit becomes converted by degrees into bony matter, as in arteries ; but instances where this has existed to any considerable extent, are very rare.\nThere are, however, some few on record. Bailie has described ossification of the inferior cava. Morgagni refers to a case observed by Bonazolius and Stancarius, in which the cava and emulgents were much dilated, and converted partly into cartilage and partly into bone. Beclard mentions an instance where the femoral vein was calcified, and it was lying in contact with a still more ossified femoral artery. Horn noticed ossification of the femoral and uterine veins. Mr. Hodgson relates an instance of ossification of the saphena, in which one calcareous patch measured an inch in length ; and Phoebus states that he saw in an anatomical museum an ossified saphenous vein taken from a patient fifty-six jears of age, who died of cancer of the stomach. By the calcareous deposit the vein was rendered thick and inflexible ; but at the points corresponding with the joints of the leg the vein could be bent. The deposition was between the coats of the vein, and was less regular than that which is found in the coats of arteries. The lining membrane was thick, opaque, and nowhere broken. Microscopically, the deposit presented irregular projections and excavations. F\u00fcrst and Bonetus have found the coronary veins of the heart\nconverted into bone. Otto enumerates instances of this change as also having occurred in the splenic, portal, brachial, femoral, and coronary veins.\nA concretion of phosphate of lime, the size of a nut, was found by Andral in the parietes of the external saphena. This might have been an attached phlebolite.\nFatty Tumours. \u2014 Fatty tumours are occasionally developed in the walls of veins around the areolar tissue. Andral mentions one, \u2014 \u201c I once saw a case of this description, in which a tumour, presenting all the anatomical characters of adipose tissue, was developed between the coats of the vena portae, near its entrance into the liver. This tumour, which was about the size of a walnut, projected into the interior of the vein, and almost entirely obliterated its cavity.*\nEntozoa in Feins. \u2014 There is upon record a unique example of acephalocysts being developed in the pulmonary veins of the human subject, in which pouches were formed for their reception. The observation was made by Andral. I quote his description in extenso from the \u201c Clinique M\u00e9dicale.\u201d\n\u201c Several of these (acephalocysts) were lodged in pouches w'ith a smooth surface, which at first seemed to be so many cysts. Others of them empty, and rolled several times on themselves, were contained in narrow canals, the elongated form of w hich they assumed. The inner surface of these canals was smooth, like that of the great pouches ; they ramified like vessels. We soon ascertained that at each pouch a vessel terminated of small calibre, which, to form it, underwent greater or less dilatation. We then dissected the pulmonary veins, at their entrance into the heart, and we traced them into the lungs : when we had come to the\u00bbr almost capillary divisions, we began to perceive several of them present a considerable number of enlargements, which were filled with hydatids. After being thus dilated, the vein resumed its original calibre ; then, a little further on, it was again dilated. The largest of the pouches might have contained a large nut, and the smallest would admit a pea. They existed equally in both lungs. The hydatids, which they contained, had all the characters of acephalocysts ; several presented small points of a dull white colour in their substance ; others presented on their inner surface a great number of miliary granulations. Most of them were burst.\u201df\nAnother entozoon, the Distoma hepaticumt has been found in the (hepatic) veins. Several examples have been recorded, but have again been questioned. The matter has, however, now been set at rest. In 1830, M. Duval, at Kennes, demonstrated to an anatomical class several of these parasites in the hepatic veins of a man. They were floating about in the fluid blood. The vessels themselves were free from any lesion.J\n* Andral. loc. cit.\nf Andral, Clinique M\u00e9dicale, p. 555.\nj Duval, Gazette M\u00e9dicale \u00e0 Paris, 1842.","page":1402},{"file":"p1403.txt","language":"en","ocr_en":"VENOUS SYSTEM.\n1403\nBibliography. Normal Anatomy. \u2014 Auten-rieth, Dissert. Inaug. Experim. de Sang. Venoso, Stuttg. 1792. Bertin, Mem. sur la Princip. Cause du Gonflement et du Regonflement de Veines jugulaires. M\u00e9m. de Paris, 1763. Breschet, Recti. Anatom. Phys, et Pathol, sur le Syst\u00e8me Veineux, Paris, 1828. Chevers, Med Gaz. vol. xxxvi. Lond. 1845. Cotungo, Del Moto Reciproco del Sangue per l\u2019interne Vene del Capo, Parte I. Meccanismo. Atti della Acad, di Napoli, 1787. Cuvier, Le\u00e7ons d\u2019Anatomie Compar\u00e9e, torn. iv. Paris, 1833. Fabricius ab Aqua-pendente, De Venarum Ostiolis, Patav. 1603, et Opera omnia Anatomica, Lips. 1687. Flourens, Anales des Sciences Naturelles, tom. xxviii. Paris, 1833. Ge-ri/ie, De Valvulis Venarum et earum Usu, Helmst. 1723. Hall (Marshall), Essay on the Circulation of the Blood, Lond. 1831. Harvey, De Motu Cordis et Sanguinis in Animalibus, Anatomica Exercitatio, Lugd. Bat. 1639. Hasse, Progressio de Fine Arteri-arum earumque cum Venis Anastomosi, Lips. 1792. Henl\u00e9, Traite d\u2019Anatomie G\u00e9n\u00e9rale, Paris, 1843. Homberg, Observation sur un Battement des Veines semblables au Battement des Art\u00e8res. M\u00e9m. de Paris, 1704. Kemper et Reichelmann, De Valvu-larum in Corporibus Hominis et Brutorum Natur\u00e2, Helmst. 1682, in Halleri Disp. Anat. vol. ii. Klanke, De Usu Venarum, Lugd. Bat. 1752. K\u00f6lliker, in K\u00f6lliker and Siebold\u2019s Zeitschrift, 1849. Lugen-buhler, De Motu Sanguinis per Venas, 1815. Marx, Diatribe Anatomico-Physiologica de Structura et Vit\u00e2 Venarum, Caris. 1819. Meckel, Handbuch der Menschlichen Anatomie, Halle u. Berlin, 1815. Morgagni, Adversaria Anatom, omnia, Lugd. Bat. 1723. M\u00fcller, On the Existence of Four Lymphatic Hearts in Amphibia. Phil. Trans. Lond. 1833. Frochaska, Opera Minora, Vien. 1800. Purkinje et Rauschei, De Arteriarum et Venarum Structura, Breslau, 1836. Senac, Trait\u00e9 de la Structure du C\u0153ur, &c. Paris, 1783. Weiss, De Structura Venarum ad movendum San guinem diverse aptata, Altdorf, 1732. Wrisberg, De Nervis Arterias Venasque comitantibus, in ejus Comment. Gotting. 1800.\nAbnormal Anatomy.\u2014Abernethy, Surgical Essays (111 Consequences succeeding Venesection). Edin. 1793. Andral, Pr\u00e9cis. d\u2019Anatom. Pathol. Paris, 1828. Arnott, Med. Chi. Tr. Lond. 1829. Balling, Zur Venenentz\u00fcndung. W\u00fcrzb. 1829. Bou-illaud, Recherches pour servir \u00e0 l\u2019histoire de la Phl\u00e9bite. Rev. Med. \u00e0 Paris, 1825. Breschet, De l\u2019Inflammation des Veines. Journ. Compl\u00e9ment, Paris, 1819 ; et Phl\u00e9bite. Die. de M\u00e9d., Paris, 1826. Carmichael, Obs. on Varix, &c. Trans. Coll. Phys. Dublin, 1818. Cruveilhier, Phl\u00e9bite. Die. de Med. Prac., Paris, 1834. Dance, De la Phl\u00e9bite, Sec. Archiv, de M\u00e9d. Paris, 1828. Davis, Med. Chir. Tr. Lond. 1823. Frank, De Phlebitide. Prax. Med. Univ., Taurin. 1825. Hasse, Pathological Anatomy. Syd. Soc. Translation, Lond. 1846. Hodgson, Treatise on Dis. of Arteries and Veins. Lond. 1815. Hunter, On the Inflammation of Veins, Ed. Med. Comment., Edin. 1775 ; and Obs. on the Inflammation of the Internal Coats of Veins, Med. Chir. Tr., Lond. 1793. Langsvert, Theoria de Arter. et Ven. Affect. Prag. 1764. Lee, Diseases of the Veins. Cyc. of Med., Lond. 1834. Lee (Henry), On Phlebitis and Purulent Deposits. Lond. 1850. Longuet, Sur l\u2019Inflammation des Veines. Paris, 1815. Ph\u0153bus, De Concrementis Venarum Osseis et Calculosis. Berol. 1832. Fuchelt, Der Venensystem, Sec. Lips. 1818. Ribes, Expos\u00e9 des Rech. sur la Phl\u00e9bite. Rev. Med., Paris, 1825.\n(S. James H. Sailer.)\nVENOUS SYSTEM (in descriptive human anatomy). \u2014 Under this head it is intended to give a connected and concise account of the descriptive anatomy of the several elements of the venous system, referring the reader to those articles which treat of the regional anatomy of the body, in which will\nbe found the application of the subject in its practical bearings, in so far at least as the large venous trunks are concerned.\nThe veins connect the capillary vessels with the heart, one of their functions being, to bring back to the central organ of the circulation the blood which has been distributed over all parts of the body : they are naturally divided into two classes.\n1.\tThe veins which concur to form the two ven\u0153 cav\u0153, and which thus communicate with the right auricle of the heart ; these constitute the systemic venous system : and\n2.\tThe veins which commence in the capillaries of the lungs, and finally discharge their contents into the left auricle : these represent the pulmonary venous system.\nThese two classes of veins differ from each other in the nature of their contents, no less than in their modes of termination, for whilst the systemic veins contain dark-coloured, and essentially venous blood, the office of the pulmonary veins is to convey red or arterial blood from the pulmonary capillaries, where it has been re-oxygenated, to the left auricle of the heart. Valves are not found in the veins of the pulmonary system, whilst they are very abundant in many of the systemic veins.\nThe cardiac veins constitute a small system apart from that of the general venous system, for not having any communication with the venae cav\u00e6 or with any of their branches, these veins open by a separate orifice into the right auricle of the heart.\nNeither can the portal veins be included in any general description of the venous system. These veins emanate from the stomach, intestines, spleen, and pancreas, and unite to form one large vessel, the vena portce, which entering the liver, branches out in every direction through that organ after the manner of an artery, and thus constitutes the system of the vena port\u0153.\nFrom the capillaries of the portal vein in the liver, another series of veins is derived, which coalesce and form larger and larger trunks, like the systemic veins generally, and ultimately, to the number of three or four, issue from the liver at its thick margin, and join the inferior vena cava. These last-mentioned veins are termed hepatic veins, or venae cavre hepatic\u00e6, and the function to which they are subservient in the economy, is that of reconveying into the general venous system, the blood which has been diverted to the liver by the ramifications of the portal vein.\n1. The Pulmonary Veins.\nThese veins commence in the capillaries of the pulmonary lobules, and by successive junctions with adjacent branches enlarge in size, whilst they diminish in number. They traverse the lungs in company with the subdivisions of the bronchial tubes and of the pulmonary arteries, the number of venous ramifications being identical with that of the arterial, and finally emerge from those organs, having formed into trunks, each of which corresponds","page":1403},{"file":"p1404.txt","language":"en","ocr_en":"1104\nVENOUS SYSTEM.\nto a lobe of the lungs. There are consequently three venous trunks for the right lung, and two for the left. On the right side the branch from the middle lobe unites with that from the superior; and hence two pulmonary veins, one superior to the other, are usually found in the root of each lung, where on both sides they are placed below but on a plane anterior to the pulmonary artery and bronchial tube. In the substance of the lungs the relative position of these parts is different, for there the branches of the veins are behind, whilst those of the artery are in front, the bronchus being interposed between both.\nThe four pulmonary veins then perforate the pericardium, and after a short course enter the most posterior part of the left auricle, those of the left side opening very close together, and not unfrequently by a common orifice.\nWithin the pericardium these veins are invested by its serous membrane, but on their anterior surfaces only. In passing to their destination, the right pulmonary veins lie behind the right auricle of the heart.\nII. The Systemic Veins.\nThe veins of this system will be described in the following order.\na.\tThe veins which form the vena cava superior, and which are'derived from the head, face, neck, thorax, and upper extremities.\nAmonst these the veins of the parieties of the thorax {azygos veins), and those of the spinal column {racliidian veins), are remarkable as serving to connect the branches of the superior with those of the inferior vena cava.\nb.\tThe veins which form the vena cava inferior, and which convey the blood fro n the lower extremities and from the pelvic and abdominal cavities. The portal veins are an adjunct to this system.\nc.\tThe proper veins of the heart (cardiac veins), which arise in the substance of that organ, and open by a separate trunk into the right auricle.\nA. The Veins which form the Vena Cava Superior.\nThese are constituted by the veins, 1. Of the head and face ; 2. Of the neck ; 3. OJ the tipper extremities ; 4. Of the thorax.\n1. Veins of the head and face. * \u2014 The superficial veins of the head and face unite to form three principal trunks, which are placed on the anterior, lateral, and posterior aspects of the cranium ; anteriorly is seen the\nFacial vein. \u2014 This vein originates in the\n* The veins of the head mav he divided into two sets, those which ramify on its exterior and those which occupy its interior; the former will alone be noticed in this place. The latter, which are represented bv the cerebral veins and sinuses of the dura mater are described in Article Nervous Centres (Dr. Todd), Yol. III. 631. Intermediate to these two systems are the veins of the bones of the head (the diploic veins), which, by their inosculations with both, maintain a free communication between the superficial and deeper seated veins, bora description of the diploic veins, see Art. Bone, Yol. I. p. 436.\nfrontal region from numerous interlacing branches, which usually give rise to one large vein on each side (frontal vein), which is joined by branches from the upper lid {palpebral) and root of the nose, and by the supraorbital vein; sometimes there is but one frontal vein placed in the mesial line, and dividing into two branches, which descend one on either side of the nose. The frontal vein continues its course in the sulcus along the inner margin of the orbit under the name of angular vein, accompanying the artery of the same name, and receives numerous branches from the orbit, by which a close connexion is maintained between the circulation on the exterior of the cranium and that of the cerebrum itself. At the lower margin of the orbit the angular becomes the proper facial vein,-which passes downwards and outwards in an almost direct course to the anterior edge of the insertion of the masseter muscle.\nThe facial vein consequently has a much shorter extent than its corresponding artery, to the outer side of which it is invariably placed ; it passes beneath the zygomatic muscles, and lies on Steno\u2019s duct, just where the latter is about to penetrate between the fibres of the buccinator muscle.\nThe facial vein receives the following branches. Veins from the al\u00e6 nasi, the coronary, buccal, infra-orbital, and masseteric veins ; and also several large communicating veins {deep facial or alveolar) from a venous plexus which is lodged in the pterygoid space.\nHaving passed below the ramus of the jaw, the facial vein enters the digastric space, which it traverses from above downwards and backwards, and lies beneath the platysma myoides and on the submaxillary gland (which consequently is interposed between the facial vein and artery) ; this vein next passes across the external carotid artery to terminate in the internal jugular vein, having been previously joined by a large branch of communication from the temporo-maxillary vein. In its course through the digastric space the facial vein receives (a), the ranine vein, which comes from the inferior surface of the tongue, passes backwards by the side of the fr\u00e6num, and accompanies the hypoglossal nerve, between the mylo-hyoid and hyo-glossus muscles; (b), the satellite vein of the gustatory nerve, which is derived from a plexus of superficial veins on the dorsum of the tongue, and communicates freely with the preceding {Cruveil-hier); (c), the submental vein, which arises in the sublingual gland ; and {d) several palatine veins which are derived from a venous plexus encircling the tonsil.\nIn many instances the facial vein unites with the proper lingual veins, and thus forms a common trunk, which throws itself into the internal jugular ; into this common trunk the superior thyroid, pharyngeal, and temporo-maxillary veins, will in such a case be frequently found to open.\nOn the lateral region of the head are placed the trunks of the temporal and internal maxillary veins.","page":1404},{"file":"p1405.txt","language":"en","ocr_en":"VENOUS\nThe temporal vein is formed by the union of two branches, which represent the superficial and middle temporal arteries.\nThe superficial temporal veins form a wide-spreading network of vessels on the lateral aspect of the scalp, which communicates with the frontal veins in front, with the occipital behind, and with the temporal veins of the opposite side across the vertex.\nThe middle temporal veins arise in the substance of the temporal muscle, where they are joined, behind the external orbital process, by branches from the orbit: these veins, by their union, form a branch which is placed at first between the temporal muscle and fascia, but subsequently perforates the latter immediately above the zygoma, and forms with the superficial temporal vein a common trunk, which enters the parotid gland, and unites with the internal maxillary vein.\nInternal maxillary vein. \u2014 In the pterygoid space the branches of veins which correspond to those given off in the same region by the internal maxillary artery, viz. the inferior dental, deep temporal, pterygoid, and (according to Cruveilhier) the middle meningeal veins (ven\u00e6 comit\u00e9s to the middle meningeal artery, which communicate in the cranium with the inferior cerebral veins), unite to form a great venous plexus placed between the pterygoid muscles, which communicates freely, as has been mentioned, with the facial vein. Arising from this plexus, the internal maxillary vein passes backwards along with its artery, between the ramus of the jaw and the internal lateral ligament of the temporo-maxillary articulation, and entering the parotid gland joins the temporal vein ; by the union of these branches the external jugular vein is formed. Many anatomists give to the upper portion of the venous trunk, formed in the manner which has just been described, the name of temporo-maxillary vein, by others it is designated posterior facial, names which are applied to it until it has emerged from the parotid gland, where, according to these authorities, the proper external jugular vein commences.\nThe temporo-maxillary vein (or that stage of the external jugular vein which is contained in the parotid gland) is joined by the branches which accompany the transverse facial and posterior aural arteries, and sends off a large communicating branch, which unites with the facial vein.\nThe temporo-maxillary vein is situated more superficially than the external carotid artery, which it separates from the plexiform ramifications of the portio dura nerve.\nOn the posterior region of the head is found the occipital vein. The ramifications of this vein are spread over the posterior portion of the scalp, and correspond very accurately to the terminal branches of the occipital artery ; the trunk which they form likewise accompanies that of the artery, passes with it beneath the splenius and sterno-mastoid muscles, and joins the internal jugular vein below the digastric muscle ; less frequently it unites with the external jugularvein. Opposite the mastoid\nSYSTEM.\t1405\nprocess, the occipital vein is joined by several branches from the mastoid region, one of which passes through a canal in the bone (mastoid hole), and communicates directly with the lateral sinus of the dura mater.\n2. Veins of the neck. \u2014 The most remarkable of these are the internal and external jugular, and the vertebral veins.\nExternal jugular vein. \u2014 This vessel is the principal channel of the superficial venous circulation of the neck. Its direction is downwards and slightly outwards, and it extends from the lower margin of the parotid gland to the subclavian vein. Crossing the sterno-mastoid obliquely, the external jugular vein descends parallel to the posterior edge of that muscle, through the supra-clavicular space, and lies on the deep cervical fascia, by which it is separated from the omohyoid muscle, brachial plexus, and subclavian artery. Finally, the vein passes forwards through an opening in the fascia cervicalis, and joins the subclavian vein. Several of the nerves of the cervical plexus are related to this vein ; many of their branches cross it as they descend the neck ; and the largest of the three ascending branches of the plexus, the nervus auricularis magnus, is parallel to the vein and to its outer side, as it lies on the sterno-mastoid muscle.\nThroughout the entire of its extent the external jugular vein is covered by the fibres of the platysma myoides, which cross its direction obliquely forwards and inwards. This vein is furnished with two sets of valves, one of which is placed at its entrance into the subclavian vein, and by this circumstance the external jugular is distinguished from all other veins of the head'or neck, in none of which are valves found to exist.\nThe branches which the external jugular vein receives are the following : first, several large veins from the posterior region of the neck ; one of these, which from its superior size, and also from its position, may be distinguished by the name of posterior jugular vein, descends from beneath the trapezius muscle, through the postero-superior triangle of the neck, and joins the external jugular vein a little below its centre. Lower down this latter vein receives, secondly, the \u201c ven\u00e6 comit\u00e9s\u201d of the superior and posterior scapular arteries. By its anterior surface the external jugular vein receives; thirdly, muscular branches\u2019, fourthly, a communicating branch, which passes beneath the sterno-mastoid muscle, and joins the internal jugular vein ; and sometimes, fifthly, the anterior jugular vein.\nAnterior jugular vein. \u2014 This vein is but seldom absent, although its size is subject to much variety ; in general its development is inversely as that of the external jugular trunk, to which it is to be regarded as supplemental. The branches of origin of the anterior jugular vein are derived from several small muscular and cutaneous veins of the supra hyoid region, which generally communicates with the facial veins. Thus formed, this vein passes down by the side of the larynx along the anterior margin of the sterno-*","page":1405},{"file":"p1406.txt","language":"en","ocr_en":"H06\tVENOUS\nmastoid muscle, beneath which it passes, a little above the clavicle, to join the internal jugular vein, close to the junction of the latter with the subclavian vein.\nThe anterior jugular vein, in its course down the neck, communicates freely with the internal and external jugular veins, and sometimes terminates by opening into the latter.\nIt receives branches from the larynx, and sometimes from the thyroid gland.\nNot unfrequently the veins of opposite sides are connected by a transverse branch, which crosses the trachea immediately above the sternum, and receives the terminations of some of the inferior thyroid veins, and of one or two subcutaneous veins from the thorax.\nInternal jugular vein. \u2014 The blood which has circulated through the brain and sinuses of the dura mater, is returned by the great lateral sinus to the internal jugular vein, which extends from the posterior part of the foramen lacerum posterius, to the root of the neck, where on each side it forms the vena in-noininata,by its union with the subclavian vein.\nIts direction is strictly vertical.\nAt its commencement this vein presents an oval dilatation (sinus, or gulph of the internal jugular vein), which is lodged in the jugular fossa, and into which the inferior petrosal sinus of the dura mater opens. The internal jugular vein is placed posterior, and external, to the internal carotid artery, (the lingual, glossopharyngeal, and pneumogastric nerves intervening,) and rests upon the anterior surface of the rectus capitis lateralis muscle ; but as the vein is traced downwards, it will be found, a little below the base of the skull, to lie parallel with, and to the outer side of, the internal carotid ; the spinal accessory nerve here descends upon the anterior surface of the vein. Subsequently, the internal jugular vein enters the sheath of the common carotid artery, along with the vagus nerve, and preserves the same relative position to that great vessel as it did to its internal branch. At the root of the neck the vein of the right side intersects, at right angles, the front of the first stage of the subclavian artery ; on the left side, the vein, whilst it is anterior, is at the same time parallel, to the thoracic stages of the subclavian and carotid arteries.\nCollateral branches of the internal jugular vein.\u2014Opposite the cornu of the os hyoides, the internal jugular vein is joined by (a) th e facial vein, and sometimes by (b) a large communicating branch from the temporo-maxillary vein, by which its size is sensibly augmented ; above the os hyoides, it receives (c) the pharyngeal vein, derived from a venous plexus on the sides and back of the phanynx ; (d), the proper lingual veins, two in number, \u201c venae comit\u00e9s \u201d of the lingual artery, the course of which they accurately follow : the lingual veins, as has been already stated, sometimes form a trunk of considerable size, by uniting with the facial vein * ; and (e), the occipital vein, which has\n* In considering the distribution of the veins of the tongue, it may be observed that there are two\nSYSTEM.\nbeen described in the preceding page. Below the level of the os hyoides, the internal jugular vein receives (f) a laryngeal branch, which escapes from the larynx through an opening in the thyro-hyoid membrane ; (g), the superior thyroid veins, \u201c ven\u00e6 comit\u00e9s \u201d of the superior thyroid artery, and which emanate from the superficial and upper portions of the thyroid gland : these occasionally terminate in the anterior jugular vein, or in the common trunk of the facial and lingual veins when it is present ; and (h) the middle thyroid veins, which pass out from the lower part of the lateral lobe of the gland, and join the most inferior portion of the internal jugular vein.\nThe vertebral vein. \u2014 The vertebral vein arises by muscular branches, which are deeply placed at the base of the skull, in the vicinity of the foramen magnum, and first exists as a distinct trunk in the foramen of the transverse process of the atlas, where it is joined by two communicating branches, one of which passes through the posterior condyloid foramen, and opens into the great lateral sinus, whilst the other is derived from the occipital vein.\nThe course and relations of the vertebral vein, from this to its termination, are identical with those of the cervical stage of its corresponding artery, which it accompanies through the foramina in the transverse processes of the cervical vertebrae. On issuing from the foramen of the sixth vertebra, it is joined by the veins which accompany the ar-teria cervicalis profunda and the arteria cer-vicalis superficialis. Lastly, the vertebral vein usually passes behind the subclavian artery on the right side, and in front of that vessel, on the left side, to terminate in the vena inno-minata. Sometimes, though rarely, the vertebral ends in the internal jugular vein.*\nThe vertebral veins anastomose very freely with the spinal veins, as well with those which are within the spinal canal, as with those which are external to the vertebrae, by means of small branches which enter the foramina, by which the cervical spinal nerves issue.\n3. Veins of the tipper extremity. \u2014 These veins are arranged in two series, a superficialand a deep ; both of which are provided with valves, but the deep veins the most abundantly.\nSuperficial Veins. \u2014 In the fore-arm and hand these veins are distributed with great minuteness in the subcutaneous areolar tissue, and anastomose freely with one another; but their larger branches chiefly occupy the radial and ulnar (the lateral) aspects of the fore-arm.\nThe radial or external superficial veins emanate from numerous venules on the thumb and dorsum of the fore-finger, and are joined\nsuperficial or submucous veins, (the ranine vein, and the satellite vein of the gustatory nerve') corresponding to the subcutaneous veins in the limbs, by which the blood is returned when the deep veins (proper lingual) are compressed during the contractions of the organ.\n* Vide Art. Subclavian Artery, Vol. IV. pp. 815. and 822.","page":1406},{"file":"p1407.txt","language":"en","ocr_en":"VENOUS\nin the fore-arm by many cutaneous branches from either side. Opposite the elbow joint these tributaries have ended in one vessel of considerable size, the cephalic vein, which, being joined by a branch from the median vein (median cephalic), ascends between the biceps and supinator longus muscles, follows the outer margin of the biceps, traverses the interspace between the pectoralis major and the deltoid, and ultimately having arrived in the subclavicular triangle, bends over the upper edge of the pectoralis minor, penetrates the thin expansion of the \u201cfascia clavicularis\u201d (ligamentum bicorne), and enters the axillary vein immediately beneath the clavicle. In some instances a branch is continued upwards from the cephalic vein, which passes over the clavicle and communicates with the external jugular vein.\nThe ulnar or internal superficial veins have their origins from veins which ramify on the dorsum of the hand and of the two inner fingers, one of which from the little finger has been long known as the \u201c vena salvatella ; \u201d others arise anteriorly from subcutaneous veins on the front of the wrist. In the vicinity of the elbow both sets of branches unite to form one principal trunk, the basilic vein, which is reinforced almost at the moment of its formation by the median basilic vein, a branch of very considerable size from the median.\nThe basilic vein, now much enlarged, ascends along the inner margin of the biceps muscle, parallel to the brachial artery, but more superficially than that vessel, (for the deep fascia intervenes,) until it arrives opposite the centre of the arm, when it pierces the brachial aponeurosis, and joins one or other of the ven\u0153 comit\u00e9s of the brachial artery. In a few instances the vein ascends as high as the axilla, and entering that space joins the trunk of the axillary vein. The superficial veins in the front of the upper part of the fore-arm unite to form a short trunk termed median vein, which by its lateral branches connects the radial and ulnar superficial veins ; near the bend of the elbow the median vein receives a large communicating branch from the ven\u00e6 comit\u00e9s of the brachial artery, and terminates by dividing into two very considerable veins, termed median basilic and median cephalic veins respectively : the latter passes obliquely upwards and outwards, over the tendon of the biceps, and joins the cephalic vein ; the former, which is the largest, inclines inwards, and in its course to join the basilic trunk passes across the brachial artery, separated from it only by the \u201c semilunar fascia\u201d of the biceps tendon.\nThe deep veins of the upper extremity accompany the ramifications of the larger arteries chiefly, which in the lower as well as in the upper extremity, are invariably attended by two veins, one on either side, hence called ven\u00e6 comit\u00e9s; transverse branches at short intervals maintain a free communication between these vessels.\nThe ven\u00e6 comit\u00e9s of the ulmar artery are de-\nSYSTEM.\t1407\nrived from veins which correspond to the digital arteries, and which form a superficial palmar arch of veins, which at its outer extremity receives branches from the deep radial veins, through which the ven\u00e6 comit\u00e9s of the radial and ulnar arteries are brought into communication with each other. The associate veins of the interosseous artery unite with the ven\u00e6 comit\u00e9s of the ulnar artery.\nThe ven\u00e6 comit\u00e9s of the radial artery commence from the palmar interosseal veins, which form a deep palmar arch across the heads of the metacarpal bones, and are joined by veins from the muscles of the thumb, and by branches of the superficial arch which follow the course of the arteria superficialis vol\u00e6. The ven\u00e6 comit\u00e9s of both the radial and ulnar arteries receive numerous tributaries from the veins of the adjacent muscles, and ultimately unite to form the\nSatellite veins of the brachial artery. \u2014 The brachial ven\u00e6 comit\u00e9s are joined by veins which correspond to the branches of the brachial artery in the arm (superior and inferior profunda and anastomotica magna), and also by the basilic vein. At the lower part of the axilla, these veins, by their union, form the axillary vein.\nThe axillary vein returns all the blood from the upper limb : it is formed by the union of the brachial ven\u00e6 comit\u00e9s (with one or other of which, in the arm, the basilic vein is continuous), whilst the cephalic vein joins it near its termination. Like its accompanying artery, the axillary vein consists of three stages, and its relations to surrounding parts are identical with those of that vessel. The vein is placed internal and anterior to the artery throughout its entire course. When the arm is abducted, the vein becomes inferior.\nIn addition to the cephalic vein, the axillary trunk receives numerous branches which correspond to those of the axillary artery, viz., the circumflex and subscapular veins, the alar, and the long, superior, and acromial thoracic veins.\nThe axillary is the last vein of the upper extremity, as we approach the heart, in which valves exist : at the lower edge of the first rib it becomes continuous with the subclavian vein.\nSubclavian vein. \u2014 This great vessel extends from the axillary vein to the inner margin of the scalenus anticus muscle, where it unites Avith the internal jugular vein, to form the vena innominata. The subclavian vein therefore corresponds to the second and third stages only of the subclavian artery ; and, as the direction of the vein is nearly transverse, whilst that of the artery describes an arch, it necessarily follows that the former vessel is much shorter than the latter. On both sides of the neck the scalenus anticus muscle, and the phrenic and pneumogastric nerves, are, interposed between these associated vessels. The subclavian vein is related anteriorly to the subdavius and sterno-mastoid muscles, to the clavicle, supra-scapular artery, platysma, and superficial structures of the neck, and","page":1407},{"file":"p1408.txt","language":"en","ocr_en":"1408\tVENOUS\nrests upon the first rib, the scaleni muscles, and the phrenic nerve, which descends between the vein and the scalenus anticus muscle. Contrary to what is observed in the case of the axillary and of most other veins of large size, the branches which join the subclavian vein do not correspond to those which are given off by the subclavian artery. The collateral branches of the subclavian vein, are the external and internal jugular veins ; the former joins it on the outer, and the latter on the inner side of the sterno-mastoid muscle. The subclavian vein not uncommonly receives the vertebral also, although, as has been stated, this vein is most frequently a tributary of the brachio-cephalic trunk.\nBrachio-cephalic veins. (Vene innominate, Meckel.) \u2014 These veins, one on each side, are formed by the union of the internal jugular with the subclavian vein ; they are apparently of the same size, but are contrasted in other essential particulars, as they are examined on the right and left side : thus they will be found to differ from each other in length and in direction, as well as in their connexions with surrounding parts, as also in the number of collateral branches which they respectively receive.\nThe right vena innominata is comparatively short, and nearly vertical in direction ; it is placed behind the cartilage of the first rib, and is related externally to the right pleura and internally to its corresponding artery, the arteria innominata ; the vein and artery however are not in close apposition, and the right pneumogastric nerve is found in the interval between them, but deeper than both; filaments of the cardiac nerves also are interposed between them.*\nThe left vena innominata, more than twice as long as the preceding, traverses the upper part of the anterior mediastinum almost horizontally from left to right, but at the same time with an obliquity downwards and slightly forwards. It is placed behind the first bone of the sternum, from which it is separated by the sterno-hyoid and sterno-thyroid muscles, and by the thymus gland ; and bending across the three primary branches of the aorta, slightly overlaps the anterior surface of the arch itself towards the right side. Immediately below the cartilage of the first rib and on the right side of the mesian line, the innominate veins unite to form the superior vena cava.\nCollateral branches.\u2014 The vertebral is in general the only vein which terminates in the right vena innominata, for although it does occasionally occur that the inferior thjroid and internal mammary veins join the vena innominata on their respective sides, yet in the great majority of instances these veins terminate differently on the right and left side : on the left they almost invariably open into\n* At the moment of its formation the right vena innominata is placed anterior, and inferior, to the first stage of the subclavian artery ; between them, however, we find the mammary artery, and the phrenic and pneumogastric nerves.\nSYSTEM.\nthe corresponding vena innominata, whilst on the right they as constantly open into the vena cava superior. It is not very uncommon for the left vena innominata to receive all the inferior thyroid veins ; and the left superior intercostal vein, which is usually connected by a large collateral branch with this vein, sometimes, but more rarely, termi* nates directly in that vessel.\nInfei'ior thyroid veins. \u2014 Although generally destribed as consisting of two principal trunks, one for each side, these veins very often consist of as many as four or more branches, which, arising from a plexus of veins in the interior of the thyroid gland, emerge from its lower border and descend on the front of the trachea, covered by the deep layer of fascia and by the infra-hjoid muscles, to open into the left vena innominata. These, veins lie in a well-defined triangular space of much surgical importance, which is bounded on the one side by the innominata, and on the other by the left carotid artery, whilst its third side, which represents the base of the triangle, is defined by the lower margin of the thyroid body : the apex is constituted by the convergence of the arteries which form its sides, to the arch of the aorta ; and in this latter direction, the space above described is somewhat encroached on by the left vena innominata. Sometimes the thyroid veins of opposite sides unite to form an arch across the trachea, and in some few instances they open into the transverse branch of communication which sometimes unites the anterior jugular veins of opposite sides.\nInternal mammary veins. \u2014 These, which constitute \u201c ven\u00e6 comit\u00e9s \u201d to the trunk of each internal mammary artery, are formed by branches which correspond with those which emanate from that vessel. _ Very frequently the two vessels unite in a single trunk, which ends, as has been stated, in the vena innominata on the left side, and in the vena cava on the right.\nVena cava superior. \u2014 This great vein receives all the blood from the head and neck, and from the upper extremities ; it is formed by the union of the two brachio-cephalic veins, and extends from the lower margin of the cartilage of the first rib on the right of the sternum, to the upper and posterior part of the right auricle of the heart where it terminates. Shortly after its formation, the superior vena cava enters the pericardium. That portion of the vein which is without the pericardium (and which is of very small extent) is invested by a sheath of the fibrous layer of that membrane, whilst its intra-pericardial stage is completely invested by the serou\u00e4 membrane, which it serves to convey to the surface of the heart. In its entire course this vein describes a curve, the convexity of which is related to the right pleura with the intervention of the pericardium, whilst the concavity touches the aorta ; the pericardium is anterior to it, and the pulmonary artery of the right side passes behind it. The principal collateral branch of the thoracic vena cava is","page":1408},{"file":"p1409.txt","language":"en","ocr_en":"VENOUS SYSTEM.\n140:9\nthe great azygos vein, which joins that trunk at the moment of its entrance into the cavity of the pericardium.\nAzygos veins.*\u2014 The azygos veins and their tributaries (which are described by Cruveil-hier amongst the superficial rachidian veins) constitute a remarkable system which is of great importance, as it assists in maintaining the circulation through the spinal system of veins, and at the same time connects the branches of the superior with those of the inferior vena cava.\nThe veins of the azygos system usually consist of three principal trunks, the greater and lesser azygos veins, and the left superior interc. stal vein.\nThe vena azygos major commences in the lumbar region, by the union of several branches from the upper lumbar veins, through which it communicates with the inferior vena cava. Sometimes the azygos vein receives a branch directly from that vessel, and frequently another from the renal vein.\nAfter a very short stage in the abdomen, the great azygos vein enters the thorax through the aortic canal in the diaphragm, and ascends on the vertebral column to the right of the aorta, from which it is separated by the thoracic duct. Having arrived at the third dorsal vertebra, the vein now changes its direction, and passing forwards and to the right side, leaves the posterior mediastinum, arches over the right bronchus, and descends to terminate in the superior vena cava; where that vessel is about to enter the pericardium.\nThe vena azygos major is joined by all the intercostal veins of the right side, and by the lesser azygos vein, through the medium of which it communicates with the lower intercostal veins of the left side also. Two or three of the middle intercostal veins of the left side open directly into the great azygos vein, it likewise communicates very freely with the left superior intercostal vein.\nThe lesser azygos vein (or left or inferior azygos vein), likewise has its origin in the lumbar region, from some of the upper lnmbar veins on the left side of the spine ; it anastomoses with the neighbouring veins which ramify on the surface of the vertebrae, and is connected, more frequently even than the greater azygos vein, with the corresponding renal vein (Breschet). The lesser azygos vein enters the thorax, either through the aortic canal in the diaphragm, or by perforating its left crus along with the left splanchnic nerve, ascends on the left side of the spine, as high as the fifth or sixth dorsal vertebra, where, crossing the front of the spinal column, behind the aorta, to terminate in the great azygos vein.\nThe veins-from the five or six lower inter-\n* As these veins have already been described in an article specially devoted to the subject, they are but briefly noticed in this place, and only in so far as was necessary to carry out the design of giving a continuous description of the elements of the venous system. Vide Art. Azygos (Dr. Harrison), Yol. L p. 364.\nVOL. IV.\ncostal spaces terminate in this vessel. In some instances there is no venous trunk corresponding to that above described, in which case the left intercostal veins cross the spinal column behind the thoracic aorta, to join the great vein of the right side, which, under these circumstances only, is appropriately termed \u201c azygos.\u201d\nThe left superior intercostal vein (left superior azygos vein) is formed by the union of the three or four superior intercostal veins of the left side. Its course is subject to some variety, but it always serves to establish a connexion between the azygos system and the deep veins of the neck. In many instances this vein passes upwards, and opens into the left vena innominata, but more frequently it descends, increasing in size as it approaches its termination in the great azygos vein. Sometimes the left superior intercostal vein terminates in the azygos minor.\nThere is sometimes a similar branch on the right side, which corresponds to the right, superior intercostal artery ; this vein is always inferior in size to that of the left side, and, like it, terminates in the great azygos vein.\nThe bronchial veins are the \u201c ven\u00e6 comit\u00e9s \u201d of the bronchial arteries, from the capillaries of which they are derived, and which they accompany throughout the lungs. They leave the root of the lung, having formed into two or three trunks, and terminate, on the right side, in the superior vena cava, or in the great azygos vein, and on the left side in the left superior intercostal vein, or in the azygos minor.\nIn the pelvis the middle and lateral sacral veins represent the azygos system ; they communicate freely with the veins in the sacral canal, and with the vesical and h\u00e6morrhoidal plexuses, and end in the common iliac veins. The sacral veins thus establish a communication between the general venous system and the system of the vena portae.\nThere are no valves in the azygos veins, although they exist in great numbers in their tributaries, the intercostal veins.\nVeins of the spine.* (Rachidian veins : Breschet.) \u2014 These veins, imperfectly known to (\u2019haussier, were first accurately described by Dupuytren and Breschetf ; they have been comprehensively arranged by Cruveilhier, who includes, under the head of spinal veins, a larger portion of the venous system than the author first quoted. By Cruveilhier the veins of the spinal system are divided into\u2014A. The superficial or extra-spinal, and B., the deep or inlra-spinal veins.\nA. The superficial veins of the spine are subdivided into the anterior and the posterior.\n* Such of the veins of the spine as are situated in the interior of the spinal canal, are described in the Article Nervous System (Dr. Todd), at page 629, Yol. III. of this work; any other than a brief notice of the subject in this place is, therefore, unnecessary.\nf Essai sur les Yeines du Rachis, 4to. Recherches Anatomiques sur le Syst\u00e8me Yeineux, fol. avec Planches.\n4 x","page":1409},{"file":"p1410.txt","language":"en","ocr_en":"1410\nVENOUS SYSTEM.\n1.\tThe anterior superficial spinal (or rachi-dian) veins, include, according to this authority, the vena azygos major, the vena azygos minor, the trunk of the right and left superior intercostal veins, the lumbar and ilio-lumbar veins, and the lateral and middle sacral veins.\n2.\tThe posterior superficial spinal veins, \u201c form an exceedingly complicated network, the meshes of which surround the spinous processes and laminae, and the transverse and articular processes of all the vertebrae.\u201d\nB. The deep or intra-spiual veins comprise the following : \u2014\n1.\tThe veins of the bodies of the vertebrae ;\n2.\tThe great anterior longitudinal veins or sinuses (Willis) ;\n3.\tThe posterior spinal veins and plexuses; all these are external to the \u201c theca verte-bralis and\n4.\tThe veins of the spinal cord itself ; internal to the theca vertebralis.\nSuperficial spinal veins. \u2014 The anterior superficial spinal veins have been already described as constituting a part of the azygos system.\nThe posterior superficial spinal veins (the dorsi-spinal veins of Dupuytren and Breschet) are derived from the muscles which fill the vertebral grooves, and thus cover the laminae and the spinous and transverse processes with a series of anastomosing vessels. In the neck they form a complicated plexus, from which proceed two large veins (posterior jugular, Cruveilhier), which communicate freely with the vertebral veins, and join the venae in-nomina\u00ee\u00e6.\nFrom the numerous venous circles and plexuses formed by the \u201cdorsi-spinal \u201d veins, communicating branches are given off\u2019, which perforate the ligamenta subflava, or pass through the intervertebral foramina, and unite freely with the deep spinal veins.\nDeep spinal veins. \u2014 1. Veins of the bodies of the vertebra; : (veines basi-vertebrales, Breschet), [vide Fig. 361. Vol. III. p. 630.], are contained in bony canals in the bodies of all the vertebrae, and are analogous to the diploic veins of the cranium. The basi-vertebral veins originate in the canallated tissue of the bone, and form larger trunks, which converge towards the posterior surfaces of the bodies of the vertebrae, where the orifices of the bony canals in which they are contained are very apparent ; on emerging from the vertebrae these veins form a plexus (transverse plexus) interposed between the bones and the posterior common ligament of the spine, and from which veins pass laterally to terminate in the anterior longitudinal sinuses. Some of the smaller venous canals pass forwards to open on the anterior surface of the vertebral column, where they anastomose with the superficial veins.\n2. The anterior longitudinal sinuses, Willis : (grandes veines rachidiennes longitudinales ant\u00e9rieures, Breschet), [vide Fig. 360. p. 630.] \u2014These extend the entire length of the vertebral column, under the form of two longitudinal veins situated within the spinal canal, along the external margins of the posterior\ncommon ligament, and consequently between the bodies of the vertebr\u00e6 and the dura mater, (hence sometimes termed meningo-rachidian veins). Opposite every vertebra these longitudinal vessels are connected to each other by the transverse plexus of the basi-vertebral veins, whilst externally , they communicate, by means of branches which pass through the series of intervertebral foramina, with the numerous veins which ramify on the exterior of the spinal column, viz., the vertebral, azygos, intercostal, lumbar, sacral, &c. These longitudinal venous channels are neither parallel to each other, nor arc they of uniform dimensions ; opposite the bodies of the vertebr\u00e6 they are most closely approximated, whilst corresponding to the intervertebral foramina they are widely separated, as if drawn outwards by the branches which are here connected with them. Each longitudinal sinus, or \u201c venus plexus,\u201d (for occasionally two or more veins enter into the formation of these channels on each side,) might therefore be described as formed of \u201c a series of plexiform arches, which embrace the pedicles of each vertebra, have their concavity directed outwards and their convexity inwards, and the extremities of which anastomose together opposite the intervertebral foramina, where they communicate with the branches on the outside of the spine.\u201d* According to Breschet, interruptions occasionally occur in different parts of these longitudinal channels, a circumstance which still further authorises this description, in which each venous arch is regarded as a separate trunk, communicating with its fellows of the opposite side, and also with similar branches above and below.\n3.\tThe posterior deep spinal veins (veines longitudinales rachidiennes post\u00e9rieures, Breschet) are likewise situated in the interior of the spinal canal, between the posterior surface of the dura mater and the front of the laminae. They there form a close interlacement of vessels (posterior intra-spinal plexuses) which is most remarkably developed in the upper part of the canal. These veins and plexuses are joined by the posterior superficial spinal veins (dorsi-spinal veins), and they communicate with the anterior longitudinal sinuses by numerous small lateral branches.\n4.\tThe proper veins of the spinal cord (me-dulli spinales, Breschet) are small tortuous vessels, which form an irregular plexus upon both surfaces of the medulla spinalis between the pia mater and the arachnoid membrane ; they communicate through the foramen magnum with the petrosal sinuses or cerebellar veins, and give off small branches which pass through the foramina with the spinal nerves to establish communications with the several evr/ra-spinal veins. The veins of the spinal cord are apparently the \u201c ven\u00e6 comit\u00e9s \u201d of the proper spinal arteries.\n\u201c The veins of the spine may be regarded, in reference to the general circulation, as establishing an unbroken communication be-\n* Oruveilhier\u2019s Descriptive Anatomy, vol. ii.\np. 808.","page":1410},{"file":"p1411.txt","language":"en","ocr_en":"un\nVENOUS\ntween the veins of all parts of the trunk, so that we can suppose one of the venae cav\u00e6 to be obliterated without the venous circulation being interrupted. The greater azygos itself, winch is generally regarded as the principal means of communication between the two venae cavae, is not, however, necessary, when we consider the arrangement of the anterior and posterior spinal plexuses. Thus, I have sometimes seen the inferior, and sometimes the superior vena cava, obliterated without any apparent increase in the diameter of the vena azygos, and, what will perhaps he thought surprising, without oedema either of the upper or lower.extremities.\n\u201c Supposing the vena cava ascendens to be obstructed from the entrance of the hepatic veins down to the renal veins, the blood would then flow back by the lumbar veins into the plexuses contained within the spinal canal ; through these plexuses it would ascend to the vertebro-costal (intercostal) veins, from thence to the azygos veins, and through them into the superior vena cava.\n\u201cIfall the jugular veins were obliterated, the venous circulation in the head would still continue, and would be carried on through the spinal veins.\u201d *\nB. Veins which form the Inferior Vena Cava.\nThe veins which unite to form the inferior vena cava transmit the blood which is derived from the lower extremities and from the viscera of the pelvis and of the abdomen.\n1. Veins of the lower extremities.\u2014 The veins of the lower, like those of the upper extremities, are divided into a deep and a superficial set; they are likewise provided with valves, which are most numerous in the veins of the former class.\nSuperficial veins of the lower extremities. \u2014 The small veins, which in great numbers exist in the subcutaneous cellular tissue of the dorsum of the foot, unite to form two principal trunks termed saphenous. These are placed, the one on the inner, and the other on the posterior aspect of the leg.\nInternal or long saphena vein. \u2014 This vein first exists as a distinct vessel a little below the ankle joint, in front of which it ascends and passes along the inner surface of the leg, at the distance of half an inch from the inner margin of the tibia. At the knee it lies behind the internal condyle, superficial to the tendons of the sartorius, gracilis, and semi-tendinosus muscles, and continuing to ascend on the internal and anterior surface of the thigh, gains the \u201c saphenic opening\u201d in the fascia lata, through which it passes backwards to end in the femoral vein, at the distance of about an inch below Poupart\u2019s ligament.\nIn this long course the saphena vein receives many cutaneous branch s, and also several communicating veins from the deep vessels. In the thigh, it is joined, near its termination, by a large branch, which comes\n* Cruveilhier\u2019s Descriptive Anatomy, vol. ii.\np. 810.\nSYSTEM.\nfrom the back of the limb, and by two or three veins which are derived from the anterior and external surfaces of the thigh. These latter pursue a direction upwards and inwards, and thus cross anterior to the femoral artery, so that they are liable to be injured by the incisions made to expose that artery. The trunk of the saphena vein itself is seldom thus endangered, as it ascends on a plane internal to the artery. Shortly before its termination, the saphena vein is enveloped in the meshes of the cribriform fascia, where it is joined by three cutaneous veins from the parieties of the abdomen, \u2014 viz. the superficial pubic, the superficial circumfiexa ilii, and the superfici l epigastric veins. When, from any cause, the circulation through the inferior vena cava is obstructed, those veins become remarkably enlarged and tortuous.\nThe internal saphena vein is accompanied, from the ankle to the knee, by the internal saphena nerve. The valves, in its interior, vary from two to six sets.\nCommunicating branches pass between this vein and the deep veins of the leg and thigh ; they are most numerous in the leg, where they connect the saphena with the anterior and posterior deep tibial veins.\nPosterior or external saphena vein. \u2014 The external saphena vein is formed by the union of several branches from the outer side of the foot, and ascends into the leg behind the outer ankle. Inclining inwards and upwards, it gains the centre of the back of the leg, passes superficial to the groove between the heads of the gastrocnemius muscle, and enters the poplit\u00e6al region. Opposite the line of flexion of the knee-joint, this vein passes through a small round opening in the poplit\u00e6al fascia, and joins the poplit\u00e6al vein about its centre. This vessel, sometimes called the short saphena vein, is accompanied in part of its course by the posterior saphena nerve. It is usually furnished with two valves, which are found near the termination of the vessel. This vein communicates but rarely with the deep veins of the leg.\nPeep veins of the lower extremity. \u2014 In the lower, as well as in the upper extremities, the deep system of veins is represented by the \u201c ven\u00e6 comit\u00e9s \u201d of the larger arteries. The satellite veins of the posterior tibial artery are derived from the deep plantar veins (external and internal). At the upper part of the leg the posterior tibial veins are joined by the satellite veins of the peroneal, and subsequently, at the lower edge of the poplit\u00e6us muscle, by those of the anterior tibial artery. By the union of these is the trunk of the poplit\u00e6al vein formed.\nThe poplit\u00e6al vein. \u2014 This vein is of large size, owing to the number and magnitude of the branches which it receives; it is joined by the tibial veins, by the externed saphena, by the articular, and, lastly, by muscular veins of large size (sural) from the calf of the leg.\nThe poplit\u00e6al vein is placed posterior to its artery below, posterior and a little external to that vessel, at the upper part of the poplit\u00e6al\n4x2","page":1411},{"file":"p1412.txt","language":"en","ocr_en":"3412\nVENOUS SYSTEM.\nspace. It is consequently situated between the artery and the posterior tibial nerve.\nThe valves in this vein are four or five in number. Its coats are stated by Cruveilhier and others to be of more than ordinary thickness.\nThe femoral vein is the continuation of the poplit\u00e6al, which latter vessel, having passed through the tendinous opening in the adductor muscles, enters the thigh, and becomes femoral. In the lower third of the thigh the femoral vein and artery (enclosed in a common sheath) are contained in \u201c Hunters canal,\u201d the vein lying, as in the ham, posterior and external to the artery. In the centre of the thigh the vein is placed directly behind the artery ; but throughout its upper third the two vessels lie side by side, and in close connection, the vein being the moi*e internal. A thin, fibrous septem derived from the sheath which surrounds them passes backwards, and separates these vessels at this part of their course. The point of the aneurism needle is apt to be entangled by this partition, in conveying a ligature round the femoral artery, if care be not taken to keep the instrument on its outer or arterial side, whilst at the same time the sheath is kept tense. At the highest point of its course, just where it is about to pass beneath Poupart\u2019s ligament, the femoral vein constitutes the external boundary of the crural ring, and would therefore necessarily bear the same relation to the neck of any hernial tumour which may have descended through this aperture. In its course through the thigh, the femoral vein is joined by numerous muscular branches, also by the profunda vein, about an inch and a half below the crural arch, and, lastly, by the internal saphena vein.\nIts valves are from three to five in number.\nBeneath Poupart\u2019s ligament the femoral becomes continuous with the external iliac vein.\nThe external iliac vein, whilst it accompanies the external iliac artery, and holds the same relation to surrounding parts as that vessel, is nevertheless differently related to its artery on the right and left side. As these vessels lie on the horizontal ramus of the pubis, their relative positions at both sides is the same, the vein being placed internal to the artery. On the left side this relation does not alter, and the vein lies on the inner side of the artery throughout its whole course ; on the right side, however, the vein, in its ascent, passes first behind the artery, and then appears slightly to its outer side.\nThe internal circumflex i/ii and the two deep epigastric veins join the external iliac vein at the commencement of its course immediately above Poupart\u2019s ligament. The former holds a remarkable relation to the external iliac artery, for it crosses that vessel at right angles to its anterior surface, and thus separates the artery from the fascia transversale.\nThe internal iliac vein is formed in the cavity of the pelvis by the union of the veins\nwhich correspond to the numerous divisions of 1 the internal iliac artery, \u2014 viz. by the glut\u0153al, j sciatic, internal pudic, and obturator veins, all I of which arise external to the pelvis ; and by ] numerous branches from the viscera contained 1 within the pelvis, and which are remarkable 1 for their plexiform arrangement. Of these, the j vesical veins form a plexus which surrounds I the neck of the bladder, and the prostate I gland (vesico-prostatic plexus'), receives the 7] blood from the dorsal veins of the penis, and j communicates freely with the inferior h\u0153mor- 1 rhoidal veins. In the female a similar plexus | receives veins from the clitoris and the labia, j and in addition there are two others, still more remarkable for their development, \u2014 the vaginal plexus, which surrounds the vagina j near its commencement, and communicates I with the vesical plexus in front, and with the | h\u00e6morrhoidal veins behind, and the uterine plexus, the veins of which are scarcely ap- | parent except during gestation, and which communicate with the ovarian veins.\nIn both sexes the lower extremity of the rectum is surrounded by the ramifications of 1 the h\u00e6morrhoidal plexus, the blood of w'hich is I returned to the internal iliac vein by the | middle and inferior h\u00e6morrhoidal veins. This plexus likewise communicates freely with the | superior h\u00e6morrhoidal veins, which unite with the inferior meseraic veins, and so constitute ! a part of the portal system.\nIn all these vessels valves exist in great numbers, although none occur in the great j trunks in which they terminate.\nThe internal iliac vein on each side is internal to its corresponding artery.\nThe common iliac veins are formed by the s union of the external and internal iliac veins. The junction takes place opposite the sacro- ] iliac symphisis. These veins exhibit on each ] side some interesting anatomical peculiarities, j\nThe right common iliac vein, nearly vertical in its direction, is placed posterior and external, < to its corresponding artery.\nThe left common Hiac vein, larger than the s preceding, and nearly transverse in its direction, \u25a0 lies internal, and inferior, to its corresponding artery, and crosses behind the common iliac artery of the right side.\nThe common iliac veins usually unite upon the intervertebral substance between the fourth and fifth lumbar vertebrae, to form the vena cava inferior. The junction occurs to the j right of the mesial line, and inferior to, as well as to the right of, the angle of bifurcation of the aorta.*\nThe collateral branches of the common iliac veins are the following : \u2014\n(a) The ilio-lumbar vein. \u2014 This vein arises in the iliac fossa, by radiating branches, which\n* The junction of the ven\u00e6 innominat\u00e6 to form the superior vena cava, as well as that of the com- S mon iliac veins to form the inferior vena cava, occurs on the right of the mesial line of the body.\nIn the former instance, the uniting veins are found on a plane anterior to the arterial trunks which they accompany ; whilst in the latter they lie behind them.","page":1412},{"file":"p1413.txt","language":"en","ocr_en":"VENOUS SYSTEM.\n5413\ncorrespond in their distribution to those of the artery of the same name, and communicate freely with the lower lumbar and sacral veins.\n(b)\tThe middle sacral vein. \u2014 A single trunk placed on the sacrum in the middle line, which communicates interiorly with the vesical and h\u00e6morrhoidal plexuses, and on each side with the adjacent lateral sacral veins. It usually opens into the left common iliac vein, but sometimes terminates more symmetrically, by bifurcating and giving a branch to either common iliac vein.\n(<?) The lateral sacral veins. \u2014 These anastomose very freely with the middle sacral and glut\u00e6al veins, and with veins in the sacral canal, before terminating in the common iliac veins.\nInferior vena cava. \u2014 (Vena cava ascen-dens.)\nThis vein, the largest in the body, since it returns to the heart all the blood which is circulated below the diaphragm, is formed by the junction of the common iliac veins, just as the superior cava is constituted by that of the ven\u00e6 innominat\u00e6. The abdominal vena cava passes upwards in front of the lumbar vertebrae, behind the liver and on the right side of the aorta. At first the inferior vena cava and the aorta are in close contact ; but as they ascend, the vein inclines forwards and to the right side, so that in the vicinity of the diaphragm these great blood-vessels become more and more remotely related to each other, and finally, the thoracic duct, the vena azygos, the right splanchnic and sympathetic nerves, the right crus of the diaphragm and the Spigelian lobe of the liver intervene between them. The anterior relations of the inferior vena cava are the following : the peritoneum, the mesentery, the inferior portion of the duodenum, the pancreas, the commencement of the vena port\u00e6, and the liver, which latter sometimes forms a complete canal for the cava. Posteriorly, the inferior cava corresponds to the vertebrae, to the psoas muscle, and to the right renal and right lumbar arteries : externally, it is related to the right kidney.\nThe inferior vena cava is not uniform in its dimensions, for it presents two remarkable dilitations in its course, the first where it is joined by the emulgent veins, and the second, opposite to its junction with the ven\u00e6 cav\u00e6 hepatic\u00e6.\nHaving passed behind, or through, the liver, the vena cava is transmitted through the \u201c foramen quadratum \u201d of the diaphragm, and at the same time penetrates the fibrous layer of the pericardium, which is here intimately connected with the cordiform tendon of the diaphragm. Above the diaphragm the vena cava bends abruptly to the left, and, after a very short, and almost transverse course within the pericardium, during which it is invested on its anterior surface by the serous membrane, terminates by entering the most posterior and inferior portion of the right auricle ; the axis of its opening is directed upwards, backwards, and to the left side* There are no valves in this vessel.\nCollateral branches. \u2014 Besides the common iliac veins, which are its formative roots, the inferior vena cava receives the following, viz., the renal, spermatic, (ovarian in the female), supra renal, lumbar, inferior phrenic, and hepatic veins.\n(a)\tThe renal veins are of great size, and pass transversely to join the cava ; the left is the longest; it passes in front of the aorta to arrive at its destination, and is joined by the left spermatic, vein.\nBoth renal veins arise in the cortical substance of the kidneys by small radicles, which unite into larger vessels : these pass between the \u201c pyramids,\u201d and so gain the hilus, where they lie in front of their accompanying arteries.\n(b)\tThe suprarenal, or capsular veins, are more numerous than the arteries of the same name ; there are usually three veins on each side, and but one artery. The veins are the superior, which joins the inferior phrenic, a \u25a0middle, which unites directly with the vena cava, and an inferior, which opens into the renal vein of its own side.\n(c)\tThe spermatic veins originate in the testis, and pass through the mediastinum testis. On entering the cord they receive veins from the epididymis, and assume a loose plexiform arrangement (plexuspampiniformis). The spermatic veins, now four or five in number, pass along the cord, and traverse the inguinal channel with the vas deferens and spermatic arteries. At the internal abdominal ring the spermatic veins leave the vas deferens and accompany their corresponding arteries, lying behind the peritoneum and in front of the psoas muscle. Continuing to ascend, these veins cross the ureters external to the common iliac arteries, approximate to one another, and finally terminate, that of the right side in the vena cava, and that of the left side in the left renal vein.\nIn the abdomen there is either one spermatic vein, on each side, or two veins which freely communicate by short transverse branches, and unite in one common trunk before terminating.\nIn the female these vessels are represented by the\nOvarian veins, which form a plexus between the layers of the broad ligament, and terminate in the same manner as the spermatic veins in the male.\n(d)\tLumbar veins (lumbo-vertebral veins).\u2014 There are four or five pairs of lumbar veins which are in every respect analogous to the lumbar arteries from the aorta: they arise by muscular branches in the lumbar region, and in the parieties of the abdomen, where they are connected with the epigastric veins, and on both sides pass behind the pso\u00e6 muscles to open into the cava close to one another : the veins of the left side cross the spine behind the aorta. The lumbar veins communicate very freely with the venous system of the spinal canal, with the ilio lumbar veins below, and with the commencement of the azygos veins superiorly.\n(e)\tThe inferior phrenic veins are derived\n4x3","page":1413},{"file":"p1414.txt","language":"en","ocr_en":"1414\nVENOUS SYSTEM.\nfrom the diaphragm, and correspond accurately to the phrenic arteries from the aorta.\nThe hepatic veins may be considered as forming an adjunct to the portal venous system, in connection with which they will be briefly noticed.\nPortal venous system.-\u2014One remarkable class of the veins of the abdomen, those of the chylopoietic viscera, do not terminate directly in the vena cava, but unite to form a large trunk\u2014vena portes, which enters the liver, and, branching out like an artery (hence the name vena arteriosa), forms a capillary system in the substance of that organ.\nThe trunk of the vena porta; is formed by the coalescence of several large veins, which return the blood from the stomach, spleen, pancreas, and from the entire of the intestinal tract, with the exception of the lower part of the rectum, many of the veins of which open into the internal iliac vein, as has been already mentioned.\nThe veins which form the porta are the following : \u2014 the superior and inferior niesen-teric, the splenic, gastric, duodenal, and pancreatic, veins. All these are destitute of valves.\n1.\tInferior mesenteric vein.\u2014 The veins of the upper portion of the rectum (superior h\u00e6morrhoidal veins), sigmoid flexure of the colon, and descending colon, unite to form this vein, which ascends behind the inferior transverse portion of the duodenum and the pancreas, and opens into the splenic vein. Bv means of the free communications which exist between the inferior h\u00e6morrhoidal veins and the h\u00e6morrhoidal and vesical plexuses, the system of the vena port\u00e6 is connected with that of the general systemic circulation.\n2.\tThe splenic vein arises in the spleen, and, accompanying the splenic artery (which lies superior to the vein), follows a transverse direction from left to right, and passes behind the pancreas to unite with the superior mesenteric vein.\nBesides its proper splenic roots the splenic vein receives the veins which correspond to the \u201c vasa brevia,\u201d as also the epiploic, pancreatic, and inferior mesenteric veins.\nThe gastric veins, of which the coronary (coronaria ventriculi) is the most considerable, likewise terminate in the splenic vein.\n3.\tThe superior mesenteric vein (grande mesnrdique, Cloquet) receives the venous capillaries from the duodenum and all the small intestines, also from the ascending and transverse portions of the colon, and passes behind the pancreas, where it unites with the splenic vein. The superior mesenteric vein corresponds to the artery of the same name, and is placed anterior and to the right of it.\nThe trunk of the vena porta;, formed by the union of these two great veins (splenic and superior mesenteric), is placed at first behind the head of the pancreas, to the right of the spinal column, and a little to the left of the inferior vena cava : it next ascends, with an obliquity backwards and to the right side, between the layers of the gastro hepatic omentum to the transverse fissure of the liver ; after hecoming slightly enlarged (sinus\nof the vena port\u00e6), it there divides into two branches, which pass horizontally into the right and left hepatic lobes respectively. Its principal anterior relations are the following : the head of the pancreas and the duodenum, the hepatic artery, and the ductus cho-ledochus ; to the two latter vessels it is related, whilst traversing the gastro-hepatic omentum ; it is surrounded by branches of lymphatic vessels and of the hepatic plexus of nerves.\nThe portal veins, and their subdivisions in the liver, surrounded by a prolongation from the capsule of Glisson, are contained within the \u201c portal canals,\u201d and are each accompanied by a branch of the hepatic artery, and by a branch of the hepatic duct. From these arise the vaginal and interlobular branches, which, by their inosculations, form plexuses which are similarly named. The interlobular veins surround the lobules on their capsular surfaces, and ultimately, having been joined by the terminal branches of the hepatic artery, enter the lobules (forming the interlobular vcms),and terminate by inosculating with the intralobular (hepatic) veins; \u201c this plexus interposed between the interlobular portal veins and the intralobular hepatic vein constitutes the venous part of the lobule, and may be called the lobular venous plexus.\u201d \u2014 (Kiernan.)\n\u201c The portal vein collects the venous blood from the chylopoietic viscera, and then circulates it through the lobules : it likewise receives thevenous blood, which results from the distribution of the hepatic artery to the structures of the liver: these two sources of supply constitute the tivo origins of the portal vein, the abdominal origin and the hepatic origin.\u201d *\nThe blood conveyed to the liver by the branches of the vena port\u00e6 is conveyed back again into the general circulation by the hepatic veins.\nHepatic veins. \u2014 These veins arise in each lobule, from the lobular venous plexus, by a vein termed, from its position, intralobular. The intralobular veins unite with others termed sublobular, which, by their coalescence from the ven\u00e6 cav\u00e6 hepatic\u00e6, these latter, usually four in number, leave the liver at its thick margin, and open into the vena cava inferior, where that vein passes between the Spigelian and right lobes of the liver.\nC. Cardiac Veins.\nThe proper veins of the heart form a separate system of small extent, which communicates with the right auricle of the heart by the great cardiac vein. Their principal trunks are thus distinguished :\n1. Great cardiac vein (anterior or great coronary vein). \u2014 This vein commences on the anterior surface of the heart, near its apex, and ascends in the anterior interventricular groove, as far as the base of the ventricles, where, bending abruptly to the left, it gains the back of the heart by passing round the left margin of the organ in the deep horizontal groove between the left auricle and the left\nVide Vol. III. p. 168., Art. Liver.","page":1414},{"file":"p1415.txt","language":"en","ocr_en":"1415\nVESICULA PROSTATICA.\nventricle. Still observing a transverse direction, the vein in its farther course, passes from left to right, crosses the upper extremity of the posterior interventricular groove, and finally opens into the posterior surface of the right auricle to the right of the mesial line.\nBefore its termination, the great coronary vein presents a bulbous dilitation (sinus of the coronary vein). Its orifice in the right auricle, which is protected by a special valve (valve of Thebesius or lesser Eustachian valve), is situated between the great Eustachian valve and the right auriculo ventieular opening.\nPosterior cardiac vein (posterior or lesser coronary vein).\u2014The lesser cardiac vein arises near the apex of the heart, on its posterior surface, and ascends in the posterior interventricular groove, where it is joined by muscular branches from either side. Finally, it terminates in the great coronary vein when that vessel forms its ampulla in the deep groove above the base of the ventricles.\nSeveral small veins, which belong exclusively to the right ventricle, ascend along the right border of the heart, and, curving round in the groove between the right ventricle and right auricle, likewise join the great coronary vein \u2014 one of those which has long been distinguished by the name of the \" vein of Galen? is stated to communicate, frequently, by a separate opening, with the right auricle.\nOther veins of extreme minuteness (vence minima or veins of Thebesius) are described as opening separately at various points into either auricle. Their existence is denied by some anatomists.\n(.B. Geo. M'Dowel.)\nVERTEBRAL COLUMN\u2014(See SUPPLEMENT.)\nVESICULA PROSTATICA. (Syn. Sinus prostata; sinus pocularis; utnculus pro-stations ; vesicvla pi ostalica media seu spuria ; uterus masculinus ; Corpusculum Weberian um.) The tubular structure indicated by this name is a part of the male sexual apparatus in Mammalia. It lies between the lower ends of the seminal ducts, and opens between them, by a special aperture, into the commencement of the urino-genital canal : an opening which has been usually, but not quite correctly, viewed as an immediate process of the urethra.\nIn Man, in whom alone it was recognised until a few years ago, it is a little vesicle, which is covered by the prostate. A \u2022 similar form and arrangement recurs in many mammalia : but others exhibit very considerable deviations. Sometimes it is altogether absent, or is but very rudimentary ; while in other instances it is of considerable size. Its relation to the prostate is equally variable ; but even in man it is only superficial, being solely due to its local arrangement,\nOn these grounds, the name \u201c vesicula prostatica\u201d which at any rate merely applies to its human anatomy, cannot always be used. We prefer, therefore, to use that of \u201c the\nWeberian organ or corpuscle,\u201d a name which has been lately proposed in order constantly to recall the great service which an eminent anatomist has rendered to our knowledge of this remarkable structure.\nE. H. Weber was the first who recognised the great morphological import of this organ, and who adduced proofs that in man and the male mammalia it is the rudiment of an organ which, by a great development in the female individual, determines the form and physiological relations of her generative apparatus. Weber* explained the vesicula pro-statica as the analogue of the uterus, and gave it the name of the uterus masculinus.\nWe would willingly accept this denomination, if Weber\u2019s view were quite correct. But since we shall hereafter point out that this never specifies the full morphological value of the vesicula prostatica, but is, in many cases, erroneous, we prefer the nomenclature already mentioned. Our examination of the Weberian corpuscle is divisible into three sections. The first regards its variations of form ; while the second considers the question of its possible functional import , and the third has for its object to determine the morphological value of this structure.\nI. Anatomy. \u2014 The Weberian corpuscle occurs only in the class Mammalia, where we meet with a greater complication of the sexual apparatus than in any other group of the Vertebrata. Thus the Mammalia are the only vertebrate animals whose females possess a real vagina and uterus. What we designate by this name in some other Vertebrata cannot be regarded as morphological equivalents of the vagina and uterus of Mammalia.\nMan. \u2014 The Weberian corpuscle is a small flask-shaped vesicle, with a rounded blind end and a narrow neck directed downwards, placed on the hinder wall of the urethra, under the verumontanum, and covered by the prostate. The middle lobe of this gland limits the upper end of the corpuscle. The length varies, but is commonly 3, 4 or 6 lines j the breadth at the upper end is 2 lines, but it sometimes attains a more considerable size. Thus Adamsj- mentions an instance in which it had a length of an inch, and by its upper end, which projected free, was placed upon the dorsal surface of the middle lobe of the prostate. And in the hypospadian described by TheileJ; its size was yet more considerable (1J inches).\nThe constricted neck sometimes forms half of the whole corpuscle, and is, according to Huschke\u00ff, sometimes separated from the\n* Annot. anat. et physiol, zu Kretzschmar\u2019s Diss. inaug. circa lineam physiol, morbor. Lips. 1836. Amtlicher Bericht \u00fcber die Versammlung Deutscher Naturforscher in Braunschweig, 1842, p. 65. Zus\u00e4tze zur Lehre vom Bau und den Verrichtungen der Geschlechts-organe (in den Abhandl. der F\u00fcrstlich Jablonowskischen Gesellschaft), Leipzig, 1846.\nf See article Prostate Gland, Vol. IV. p. 151,\nX M\u00fcller\u2019s Archiv f\u00fcr Physiologie, 1847, p. 23. Tab. III. tig. 4., copied by Adams, loc. cit. fig. 106.\n\u00a7 Soemmerring\u2019s Lehre von den Eingeweiden. Leipzig, 1844, S. 409.\n4x4","page":1415},{"file":"p1416.txt","language":"en","ocr_en":"1416\nVESICULA PROSTATICA.\nupper dilated part by a kind of constriction. The under end opens by a small elongated oval aperture (of \u00a3 to % line) on the anterior declivity of the verumontanum. The orifices of the two ejaculatory ducts* lie right and left of the opening, at a very small distance from it, usually somewhat higher, yet never quite symmetrical: they are sometimes close to it, or somewhat behind it. These ducts pass up the sides of the Weberian organ, and receive it between them, being bound up with it by areolar tissue.\nFig. 873.\nPerpendicular Section of the Weberian corpuscle h Man (copied from Weber's Zus\u00e4tzen.)\na. Urethra ; b, Weberian corpuscle ; c, vas deferens, with vesicula seminalis ; d, prostate.\nIn the Weberian corpuscle of two newborn infants, H. Meckel f found a special variety of structure. It became thinner in its ascent, so as to be only permeable by a hog\u2019s bristle, and ended as a solid thread, which separated by bifurcating.\nMorgagni J was the first who accurately described the Weberian organ, which he also probably discovered. Of fifteen human bodies which he examined with this object, he found it in fourteen. It is possible that in the one remaining case he overlooked it, since it sometimes happens that its mouth is but small, or is even altogether deficient, as Buschke has frequently ascertained it in healthy and robust suicides. Nevertheless it is not improbable that in some cases there is a complete absence of the Weberian corpuscle; the less so that we sometimes verify such dif-rences in other animals. In two of these fifteen cases, Morgagni found that the utri-culus, instead of opening by a special aperture, communicated with one of the ejaculatory\n* See Prostate, Vol. IY. fig. 103.\nf Zur Morphologie der Harn- u. Geschlechtswerkzeuge. Halle, 1848, S. 48. Tab. IT. fig. 23.\n$ Advers. Anat. IY. Animadv. 3. Yenet. 1762,\np.-110.\nducts. But at all events this is a rare anomaly, which has been since observed by Adams only.* In a case mentioned by Hyrtl-f*, there was a simultaneous deficiency of both vesicul\u00e6 s\u00e9minales, and the ejaculatory ducts descended into the upper end of a single receptacle, which was one inch long and seven lines broad. But though Hyrtl and Theile regarded this structure as certainly an uterus masculines, and thus as a Weberian organ; yet the insertion of the ejaculatory ducts at the upper end is a circumstance which contradicts their view. As we shall hereafter show, such a connection is a morphological impossibility. Even where an immediate communication between the vasa deferentia and the Weberian corpuscle exists (as is normally the case in the hare), it occurs only at the inferior extremity of the latter organ.\nQuidrumana. \u2014 In the Apes a Weberian\nFig. 874.\nWeberian corpuscle of Tnuus Cynomolgus, as seen by a perpendicular Section.\na, Urethra; b, Weberian organ; c, vas deferens with seminal vesicle ; d, prostate.\ncorpuscle appears very general. It here incloses a small, narrow and flat canal, which above has a blind extremity, and scarcely possesses a greater width than at its lower end. Its length is about two lines. Its mouth, in the uro-genital canal, is surrounded as with a wall by an annular swelling, which has some resemblance to a small os tinea?, and in which one may also, generally, distinguish an anterior and posterior lip. Immediately behind this opening are the mouths of the ejaculatory ducts, the lower ends of which are apposed to the hinder wall of the corpuscle, and are covered by the prostate.\nAs far as my researches go J, the above description will apply to the Weberian organ in all Apes. At least I have found it thus in Inuus Cynomolgus (in whom it was formerly described by Bergmann $), in Inuus nemes-Irinus, Cynocephalus Maimon, and a species of Harpale (Harpale Iacchus ? ) which, with all the animals I examined, was placed at my\n* Adams, loc. cit. p. 153.\nt Oesterreiche Medic. Wochenschrift, 1841, S. 45.\nj Zur Anatomie u. Physiologie der Geschlechtsorgane. G\u00f6ttingen, 1847, S. 99.\n\u00a7 Wagner\u2019s Handw\u00f6rterbuch der Physiologie, Bd. III. Abth. 1. S. 130. Anmerkung.","page":1416},{"file":"p1417.txt","language":"en","ocr_en":"VESICULA PH\u00dcSTATICA.\nJ417\ndisposal from the stores of the Physiological Institute of this place.\nVolitantia.\u2014 Among the Bats I have found a Weberian organ hitherto only in Vespertilio murinus. Here it is a small corpuscle, scarcely one line in size, between the ejaculatory ducts. It is covered by the prostate, and opens at the usual place by a small and scarcely visible aperture. In Flecotus auritus I have sought after it in vain. So also in Galeopithecus variegatus, where the points of opening of the two seminal ducts are placed close together upon a small and elongated verumontanum.\nInsectivora. \u2014 The Erinaceus Europeans Tulprt Europ\u00e6a*, Sorex araucus, and Macro-scelides Rozeti were examined : only in the last is a Weberian organ present. It is a roundish flask, which is proportionately of a very considerable size, being fully one line long, and quite as broad at the end. It opens, by means of a short constricted neck, into the uro-genital canal between the two seminal ducts. The prostate, which consists, as in the Sorex. of two compound gland-tubes, lies in front of the utriculus, and close to it, but without covering it. The thickened lower ends of the seminal ducts receive it between them, and are united to it by areolar tissue.\nFerce.\u2014In the dog and the cat the Weberian organ forms, as Weber has shown, a long small bladder of some lines in size, which is, for the most part, placed before the prostate in a fold of peritoneum stretching between the two ejaculatory ducts. There is no opening into the urethra.\nThe description of Weber f certainly holds good in many instances, yet not in all. I have examined numerous dogs and cats, and have very frequently found, instead of a vesicular structure, a simple solid cylindrical cord, which I have regarded as an obliterated rudiment of the organ. In many individuals even this could not be detected. 1 also found the Weberian organ as a solid cord in the fox and leopard. The striped hy\u0153na, on the contrary, possesses an elongated flaskshaped Weberian corpuscle; but it, together with the ends of the seminal ducts, is hidden between the two kidney-shaped halves of the large prostate.^ The latter are only fused posteriorly ; in the larger anterior half they are united by areolar tissue into a common mass. There is no opening into the urogenital canal, and I have found none in any of the beasts of prey examined.\nThe Weberian organ of the otter, which\n* The commencement of the uro-genital canal in the Eimacera and Talpa, forms in an anomalous manner a spacious and defined cavity. Into this cavity the urethra opens, as in the female mammalia, by a narrow slit-shaped aperture. This was described by me some time ago (zur Anatomie, &c., SS. 102. 105.) at which period I erroneously explained the cavity as a male vagina.\nf Zus\u00e4tze, &c. Tab. VII.\nX The length of the prostate is fully one and a half inches : its breadth is yet larger. Cowper\u2019s glands are also of considerable size, two inches long. They have a longly clavate form, and a very thick covering of striped muscular fibres.\nFig. 875.\nWeberian Organ of the Hy\u0153na Striata (reduced to half the natural size.')\na, Weberian organ ; b, b, vasa deferentia; c, c, prostate ; d, d, Cowper\u2019s glands.\nLeydig* has described, is of unusual form, and much more considerable development. It lies between the urinary bladder and the two seminal ducts, and consists of a body about six lines in length and proportional breadth, the upper free end of which is drawn out right and left into a long and thin thread lying on the seminal duct. The cavities and their openings could not be examined ; but without doubt both were present. The Weberian organ is very similar in the Meies Taxus. It is a very considerable cylinder, which measures about ten lines, and rises to the hinder surface of the glandular ends of the vasa deferentia, being very firmlv united to them by areolar tissue. The upper end is folded into two horns, only the right of which is permeable to a short distance. The left* is, from its root onwards, a solid thin thread, which is closely attached to the\nFig. 876.\nWeberian Organ of the Badger, a, Weberian organ ; b, b, vasa deferentia ; c, threadshaped horns of the Weberian organ.\n* Zeitschrift f\u00fcr Wissentsehaftliehe. Zoolog, von Siebold u. K\u00f6lliker, Band IL S. 49.","page":1417},{"file":"p1418.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\n1418\ncorresponding vas deferens. Its cavity is that of a canal, but not so wide a one as might he guessed from the exterior thickness of the body ; and it opens by a distinct aperture on the verumontanum.\nPinnipedia. \u2014 The genitals of a young male seal, probably Phoca vitulina, were examined by me. Here I saw a scarcely visible linear fold, which led to a longish Weberian organ of about two lines in si/e. The fold lay close behind a small ridge-shaped verumontanum, on which were the orifices of the vasa defe-rentia, situated close to each other. As in the dog, the organ is situated partly in front of, partly beneath, a prostate, which in form and development also corresponds with that gland in the dog.\nMarsupialia. \u2014 In Didelphys Virginiana the only animal of this order whose male genitals I had, no trace of the Weberian corpuscle was present.\nRodentia. \u2014 The Weberian organ showed\nmanits, and Hypud\u0153us amphibius, I have looked for it in vain. But certainly the My-oxus Vitela, Dipus \u00c6gyptiacus and Cricetus vulgaris exhibited a single small longitudinally-folded verumontanum, which, from its situation between the two orifices of the vasa de-ferentia, must have beeu the opening of a Weberian organ : but this structure iself, on account of its sheer minuteness and hidden situation, eluded the further searches, which were made in only a few' individuals.\nIn Cavia cobaya the Weberian organ is, as I described it some time since*, a small roundish vesicle, scarcely a line in size, which has a bilobed extremity, and, as in Macro-scelides, a constricted neck, which opens into the uro-genital canal between the two seminal ducts. The Weberian organ of the rabbit and hare is very much larger. It was formerly known to the older zootomists under the name of the azygous seminal vesiclef and has only received a more accurate description and ex-\nFig. 877.\nWeberian Organ of the Beaver (after Weber.~)\\ a, a, Vasa deforentia; b,b, Weberian organ; c, c, prostate; d, d, seminal vesicles.\ngreat variations in occurrence, size, ami shape. In Sciurns vulgaris, Tamias striata *, Spermo-philus atillus, in Mus musculus and dccu-\n* The Cowper\u2019s glands of this animal are cylindrical structures of very considerable size (almost half an inch long); they have knot-shaped thickenings at their end, and are rolled up in a coil around this extremity. The prostate consists of two large gland lobes which have the form of a hammer.\nplanation through the researches of Huschke and Weber.\nIn the rabbit this organ attains a length of from one to one and a half inches, so that it\n* Zur Anatomie, & c. p. 104.\nf See fig. 281. Art. \u00c8odentia, Yol IY. p. 393. (Rymer Jones.)\n7 This engraving is copied from the \u201c Zus\u00e4tze,\u201d &c.","page":1418},{"file":"p1419.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\nprojects very far,behind the urinary bladder. It has the form of a flask, and in its anterior half, which is compressed somewhat flat, it has a breadth of five to six lines. Its base is bi-lobed, as if drawn out into two lateral short and rounded horns. Its mouth in the urogenital canal is wide (about one line), yet not round or linear, but rather placed across, and somewhat arched in shape, as if bent around the swelling of the verumontanum. In newborn individuals the organ is much smaller, scarcely three lines long ; but it is otherwise exactly similar. In the male hare it is always smaller. In one example it measured five lines, and was devoid of horns at the base ; but these are sometimes little developed in the rabbit also. But the most extraordinary circumstance about the utriculus of these animals is this, that it receives the ejaculatory ducts. In all other instances, these open independently, by its sides, into the uro-genital canal ; but here, departing from this rule, they open into the undermost part of the Weberian organ, at a short distance (in the new-born rabbit half a line, in the adult two lines) above its orifice previously described. They occupy the anterior wall of the organ, on which they course downwards, and each terminates in a small papilla. In Lagcmis the same arrangement seems to occur. At least Pallas* * * \u00a7 states of the Lagomis ogstona that the two ejaculatory ducts open together by a common tube, which must doubtless be regarded as a Weberian organ, j-\nAnother very remarkable form of Weberian organ is possessed by the heaver. The first information concerning it we owe to Brandt and RatzeburgJ, who compared this structure, on account of its form, to the uterus bicornis of the female individual, yet without recognising any nearer relation between the two. They regarded it as a kind of supplementary seminal vesicle. Its correct interpretation is due to the acuteness of Weber.\u00ff\nThe Weberian organ is simple only at its lower end, or that which usually opens between the orifices of the two vasa deferentia. Very soon it is split into two horns, which ascend in the peritoneal fold between the two seminal ducts, and finally, after they have dwindled to the form of threads, are apposed to these. Brandt and Ratzeburg were able to follow the terminal threads to the testicles; while in the example which Weber investigated, where the horns measured 2% inches, they ceased much earlier. The lower half of the horn is of very considerable thickness, as\n* ]STov. Spec, quadruped, e glirium ordine. Erlangen, 1778, p. 67.\n-j- According to Rymer Jones (loc. cit. p. 398.), the two vasa deferentia in the Agouti also open by a common diict into a cavity of the verumontanum. But since this at the same time receives the excretory ducts of the seminal vesicles, it certainly is' not the cavity of the Weberian organ. Probably the same structure is repeated here which I formerly (loc. cit. p. 130.) described in the Cavia, and have recently found in the Dipus.\nJ Medizinische Zoologie. Band I. S. 137.\n\u00a7 Amtlicher Bericht., &c., loc. cit.\n1419\nmuch as four lines, and it encloses a spacious cavity.\nEdentata. \u2014 The sloth (Bradypus tridac-tylus), the only animal of this class of Mammalia whose genitals I was able to examine, is completely devoid of this organ.\nPachydermata \u2014 Duvernoy* mentions the Weberian organ in the elephant as a deep, blind sac, which lay concealed in the verumontanum. In the swine it has been described by Weber. It consists here of a body, which is nine lines in length and almost a line in thickness, and which lies in the peritoneal fold between the two ejaculatory ducts. At its upper end it passes on either side into a \\ et longer but thinner horn. Leydig, who also mentions the opening of this body into the uro-genital canal, states that, when in the inflated condition, it has the thickness of a goose quill.\nIn an adult hoar with hypospadias, I found this organ of yet larger size. The opening, which lay between the points of aperture of the two ejaculatory ducts, and had a length of 1J lines, l\u00e7d into a cylindrical body, which, gradually dilating to some extent as it passed upwards, finally, after a course of fourteen lines, split into two horns. These were placed against the seminal ducts, and, as cords of areolar tissue, could be followed with the coverings of those tubes to the testicles. In other instances the Weberian organ of the pig experienced a more considerable reduction. Thus in a new-born individual whom I examined, I found only a single solid cord in the middle line of the peritoneal fold between the vasa deferentia ; it had neither cavity nor opening into the uro-genital canal.\nSoliditngula. \u2014 The Weberian organ of the horse, which is generally of very considerable size, was known to Cuvier j-, who referred it to the vesicula seminalis. It has also been frequently described and figured by Gurlt J as a median seminal vesicle. The first who recognised its morphological importance was Hausmann.\u00a7 With a reference to the older researches of Weber upon the vesicula pro-statica of man and the beaver, but before this author had published his later observations on the horse, he explained it as the male uterus. And independently of him, Adams || was led to the same result.\nThe Weberian organ of the horse is a wide tube, which opens into the uro-genital canal by a large opening between the two vesicul\u00e6 s\u00e9minales, the ejaculatory ducts of which it receives fly the constricted neck of its lower extremity. In particular instances this opening is, as Leydig observed, divided by a median bridge into two apertures, which lie close to\n* Cuvier, Le\u00e7ons d\u2019Anatomie compar\u00e9e, nouv. edit. t. viii. p. 210.\nj- Cuvier, Le\u00e7ons d\u2019Anatomie compar\u00e9e, nouv. edit. t. viii. p. 176.\n% Anatomie der Hussa\u00e4ugethieren, Berlin, 1834, Th. II. S. 99. Anatom. Abbildungen der Haus-s\u00e4ugethieren, Berlin, 1844, Tab. 69.\n\u00a7 According to the communication of Bergmann. Op. cit.\n|| Loc. cit. p. 152.","page":1419},{"file":"p1420.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\n1420\neach other ; or it is even, as Weber found it, completely closed. In the same manner Gurlt found that the Weberian organ, instead of opening by a special aperture, sometimes communicated with one or other of the ejaculatory ducts. The lower end of the tube is considerably dilated for a length of 1 to 3 inches. Above, this dilated part generally passes into a narrow cylinder, which\nRuminantia. \u2014 In the Llama, which possesses a heart-shaped parenchymatous prostate, I have been unable to find either a median, single, opening into the commencement of the uro-genital canal, or a Weberian organ. But, on the other hand, one finds a very distinct rudiment in the new-born male deer.* Here it courses as a single cord-like thread in the peritoneal fold between the two eja-\nFig. 878.\nWeberian Organ of the Ass (reduced in size.) a, a, Vasa deferentia, with the seminal vesicles, b, b; c, Weberian organ.\nsometimes attains a length of 5 to 7 inches, and then divides into tw\u2019o short and usually unequal horns. Not unfrequently this upper part is, as was observed by Leydig and seen by myself, a simple solid thread. In the instance described by Weber the cavity was altogether absent ; and an absence of the whole Weberian organ has been observed by Leydig.\nIn the male ass I have also seen a very con-derable Weberian organ {fig. 878), the^existence of which I was first made aware of by Bergmann. It is here a straight canal, four and a half inches long, which ascends in the peritoneal fold between the two ejaculatory ducts, and divides at its extremity into two, much wider, horns. These have blind ends, and a length on the right side of 5, on the left of 9, lines. There is no opening into the urogenital canal, but the lower end has a vesicular dilatation of four lines in length, and is separated by a longitudinal fold into two blind sacs lying close behind each other.\ndilatory ducts until finally it bifurcates at about an inch from the place of their insertion. It is only during the earlier stage of embryonic life that I have been able to find a cavity and its opening: in the new-born individual the Weberian organ is already obliterated and solid. Some larger and smaller hydatidous vesicles which are found in its course, and especially at the site of its bifurcation, are the only relics of this its earlier condition.\nThe same form of Weberian organ is repeated in the goat ; but its development seems here to be very variable. I examined a large number of genitals, which had been preserved some time in spirit. In all, the Weberian organ was of considerable size and development. Nevertheless I have reasons for the conjecture that this is not the rule, and that\n* See my description in the G\u00f6ttingische Gelehrte Anzeige, 1848, No. 174.","page":1420},{"file":"p1421.txt","language":"en","ocr_en":"YESIC\u00dcLA TROSTATICA.\n1421\nFig. 879.\nWeberian Organ of the Deer.\nFig. 880.\na, a, vasa deferentia ; b, b, seminal vesicles; c, Weberian organ.\nWiberian Organ of the Goat.\nseminal ducts ; b, b, seminal vesicles; c, Weberian organ.\nin the majority of he-goats a less complete development of the Weberian organ occurs.\nAccording to my observations the organ consists of a cylindrical body, which ascends between the two seminal ducts, and is strongly united to these by areolar tissue, especially in its inferior half. After a course of an inch and a half it splits into two horns, which are apposed to the seminal ducts, and continue with these to the testicles, where they pass into the covering of the epididymis. In two instances the lower third of the body was dilated into a longish vesicle of about three lines in diameter, while the part above this measured scarcely one line. At the seat of bifurcation it was again dilated, though less considerably. In one individual the middle portion was obliterated so as to form a solid cord. The point of opening into the uro-genital canal is a small linear fold, which is separated by a short interval from the orifices of the vasa deferentia, and is usually placed below, but, in one instance, above them.\nThe genitals examined were those of either new-born individuals, or of such as were but a few weeks old. In two instances, which were in no way distinguished by a special development of the Weberian organ, the urogenital canal was wider and shorter than normal, measuring from 2 to 2\u00a3 inches long only, instead of about 4 inches, while the penis was smaller, and twisted into numerous zigzags or spirals. But in other respects the male organs were quite perfectly developed ; the urethra opened at the extremity of the penis, and the testicles had descended into the scrotum.\nIn the sheep there is no Weberian organ. Even in the new-born individual, neither its opening nor any other indication of it can be\nfound. But in the lulloclt I found immediately under the orifice of the vasa deferentia a small and scarcely noticeable roundish aperture, through which a probe penetrated about two lines in depth, evidently into the tubular cavity of a small Weberian organ, which was covered by the heart-shaped mass of the prostate.\nFig. 881.\nWeberian Organ of the Monodon. a, verum ontanum ; b, b, orifices of the vasa deferentia; c, orifice of the Weberian body.\nCetacea.\u2014 Some time ago* I described the Weberian organ in the narwhal and dolphin. It lies in the prostate, beneath the conspicuous\n* Zur Anatomie, &c., S. 100.","page":1421},{"file":"p1422.txt","language":"en","ocr_en":"1422\nYESICULA PIIOSTATICA.\nverumontanum, and possesses a flask-shaped cavity of about one inch in depth. The opening at the lower declivity of the verumon-tanurn is a fissure which has the shape of a horse-shoe curved forwards, while a triangular papilla, which arises from its posterior margin projects into it. In the Monodon the latter is farther separated by a linear fissure. In a dolphin (Delphinus orca ?) which I examined, the anterior extremity of this papilla was united with the opposite margin ; so that the opening was divided into two fissures converging superiorly. In the same way Leydig observed it in Delphinus phoc\u00e6na ; while in another individual of the same species I have met with the condition previously described. Possibly in younger individuals of the Cetacea the Weberian organ has a yet greater development. At least Eschricht, who was not aware of the structure just described, states* that, in a male embryo of the Pterobal\u00e6na, the inferior extremity of both vasa deferentia was connected with a transverse fold, of which the free margins exhibited the appearance of an obliterated cord. From its situation this would about correspond to the lateral horns of an uterus.\nII. Physiology.\u2014We, now, proceed to enquire what is the use of this structure, the occurrence and variable forms of which we have hitherto been treating of. It is a general law that the physiological import of an organ stands in a direct relation with its anatomical development. \u00bb If we regard the Weberian organ in this point of view, we shall soon be convinced, from its absence in many Mammalia, and from the varieties of its development in particular individuals, that its influence upon life cannot be very important.\nWhen Morgagni first discovered the human Weberian organ, he thought that it was connected with the prostate. Its situation made him think it possible that some tubes of the prostate emptied themselves into it, and that it was in a certain manner, like the gallbladder, a saccular dilatation of the excretory duct of the prostate. But anatomical research soon convinced him that his conjecture was necessarily erroneous. A communication between the prostate and the Weberian organ never exists, and is indeed rendered impossible by an arrangement like that which obtains in the horse, the goat, and the beaver.\nAccording to other views, the Weberian organ has the function of a seminal receptacle. Thus it has received the name of a vesicula seminalis. But we know how prone the earlier anatomists were to this designation, and how they indicated in this manner all those accessories of the male genitals of Mammalia which opened near, or together with, the ejaculatory ducts, without any closer acquaintance with their structure and import. More recent researches f have corrected us on this point. They have shown us that the\n* Untersuchungen \u00fcber die nordischen Wallthiere, Liepzig, 1849, S. 102.\nt Leydig, 1. c.\ndependent structures known as the dual seminal vesicles of the vasa deferentia almost always possess a glandular texture, and never, or only occasionally (as in man), contain spermatozoa. It is true that the flask-shaped seminal vesicles of the horse and ass are genuine reservoirs of sperm, \u2014 as we may conclude from the fact, that the vasa deferentia open into them, \u2014 but as a rule exactly the reverse relation obtains.\nBut the same anatomical arrangement as that of the vesicula seminalis in the horse may be seen in the Weberian organ* of the hare previously mentioned. On this ground only one might conclude a similar functional import. And the microscope really brings proof that the contents of the Weberian organ are, in this instance, sperm.\nBut the connection of the excretory duct and the Weberian organ is limited to the hare and lagomys. In all the other Mammalia the two structures open near to each other without any communication. Now if, in spite of this, the Weberian organ has the function of a seminal receptacle, this can only happen by the sperm, which has been previously poured into the urethra, being discharged through the lower aperture of the Weberian organ into its interior.\nWe will not quite deny the possibility of such an occurrence ; but the probability of it seems but small. At any rate a contraction of the muscular layer around the urethra would be necessary thereto; but, without offering any new hypothesis, it would scarcely be possible to perceive why the sperm should thus be sent upwards rather than downwards. The verumontanum alone would not be able to prevent this.\nSuch considerations would be silenced by direct observation ; but hitherto no one has ever met with real semen in the Weberian organ, except in the hare. Morgagni states, that on pressing the human vesicul\u00e6 s\u00e9minales, he has seen sperm exude from the prostatic utricle. But the correctness of this statement is rendered very doubtful by the fact, that the examination was made at a time when the accurate diagnosis of semen was not yet understood. A fluid may certainly have exuded from the Webenan organ, but that it w'as sperm is very doubtful. It might easily form the contents of the Weberian organ, where, as is sometimes the case, this has an abnormal communication with one or the other vas deferens.\nI will not bring forward further arguments against the import of the Weberian organ as a seminal vesicle, such as its little capacity in many instances, &c. They would only prove that such a function is sometimes impossible.\nA third theory of the function of the vesicula prostatica has been lately suggested by Weber. According to this view it is a kind of valvular ventricle, by which the urine\n* As has been also remarked by Leydig. H. Meckel, on \u00e0 priori grounds, wrongly denies this connection in the hare.","page":1422},{"file":"p1423.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\nis hindered from penetrating the vasa defe-rentia. In order to this, the urine must, like the semen in the previous view, enter into the vesicle, which, distended by it, must by its own pressure close the ejaculatory canals. Hence the same difficulties recur as in the first case. Since the urethra contains urine only during the act of micturition, and is at other times empty and collapsed, this fluid must, even in its passage through the tube by which it is discharged, pass into the vesi-cula : a fact which is the less supposable, inasmuch as to this end a backward movement of the urine would be necessary. Besides in many cases the situation of the Weberian organ is such that, even if distended by a fluid, it could not possibly operate in such a way. And moreover, even where it might perhaps be possible, it seems unnecessary, since the tumid or papillary margins of the orifices of the vasa deferentia are sufficiently closed by the passage of the urine itself.\nOne other conjecture of the physiological value of the Weberian organ still remains to us, \u2014 viz. that it is a secretory apparatus. It was found by the older anatomists that here and there, for instance in the horse, it was filled with a thick fluid, mostly of a yellow tint. As was previously remarked, this can only be secreted by the coats of the Weberian organ. Morgagni mentioned that the inner clothing of the organ was a mucous membrane, and possessed a glandular texture ; and the later researches of Huschke and Leydig have succeeded in verifying a number of small glands therein. These glandules have a different form in the different animals ; for instance, in the rabbit they are simply spherical ; in the boar they are elongated tubes provided with buds and processes.\nWhether such glandules always exist in the Weberian organ must be verified by further careful researches. Leydig could not find them in the dolphin, nor could I in the dog. At any rate they are absent where, as in the deer, &c., the cavity has disappeared.\nExteriorly to this mucous membrane, which possesses a layer of cylindrical cells as an epithelium, there is a layer of smooth muscular fibres, which take the longitudinal direction. In the hare only, in whom they form a considerable layer, especially at the lower end, they are more twisted together. It is evident that this latter arrangement is connected with the import of their Weberian organ as a seminal vesicle. At all events they are thus susceptible of more powerful contractions, which one may produce in the recently dead animal by galvanic and other stimuli for a considerable time.. Together with these muscular fibres there is a quantity of areolar tissue with white and yellow fibres. This sometimes predominates, and where the cavity disappears, it seems to occur alone.\nIt can no longer be doubted that the Weberian organ, at least where it is completely developed, and possesses an internal\n1423\ncavity and an opening, may prepare a secretion; but the nature and physiological import of the secretion are as yet unknown to us. H. Meckel* states, that he once found a clear vitreous mass in the Weberian organ of the rabbit, which from its re-actions was gelatine. Nevertheless it is very improbable that the secretion always consists of this substance, at least if I can judge from its external physical properties.\nThis secretion may easily be carried away from time to time with the urine or the sperm. Whether it plays any further part \u2014whether it is possibly, like the secretion of the prostate, subservient to the dilution of the semen (as may be conjectured from the arrangement of the Weberian organ in the hare) or to other purposes, we know not. After all, however, the function of the secretion can scarcely be an important one.\nIII. Morphology. \u2014 It is impos.-.ible that we should be quite satisfied with what we have learnt above concerning the physiological value of the Weberian organ. Granting that, in some instances, it serves as a seminal receptacle, that in others it delivers up the product of secretion, still its essential import is certainly not thus exhausted. It seems that the application of the Weberian organ to this or that end is but a casual result of its general situation, rather than that it constitutes a sufficient reason for its presence. We are constrained to adopt such a view by the circumstance, that the Weberian organ is frequently devoid of all connection with other structures, and is even sometimes reduced to a ligamentous thread, the functional value of which one cannot imagine.\nThus the Weberian organ takes a rank amongst that class of structures which possess not so much a prominent functional value, as a morphological import ; which are necessitated not so much by the actual requirements of life as by the general typical plan of the structure. Should any one deny the existence of such a class of structures, it would only be necessary to remind him of the wing-stumps of many apterous insects, of the bony girdle for the extremities of the blind worm, of the embryonal teeth in the bearded whale. All these are parts which are of scarcely any physiological value to the animals named, although under different circumstances, and in other animals they fulfil the most important functions : they are simply morphological rudiments, which, according to the common architectonic law, are repeated even where they are useless.\nBut such parts are found, not merely in particular animals and groups, but also especially in the different sexes. Of what use to the male individual are the milk-glands and teats ? of what use to the female the well-known rudimentary penis called the clitoris ? Are they not the plainest indications that the male and female organs are constructed after a common type, and that it is only by different developments of the same elements that they * Op. Cit. p. 49.","page":1423},{"file":"p1424.txt","language":"en","ocr_en":"1194,\tVESICULA PROSTATICA.\ntake their different forms, and with these their different destinies? Careful contemplation leads us to regard the Weberian organ as one of this class of structures. As was previously mentioned, Weber had pointed out, that by its situation and connection with the uro-genital canal, and very frequently (as in the beaver) by its form, it corresponds so completely to the uterus of the female mammalia, that there is every reason for regarding it as its morphological equivalent in the male individual.\nAccording to this view, the difference between the Weberian organ and the uterus is limited to that of a lesser or greater degree of development. In the female individual it becomes the receptacle of the embryo. The physiological task which it thereby undertakes demands a complete development, while in the male individual, in whom it has not such an important functional import, and is only occasionally applied to this or that subordinate purpose, it undergoes a check, or even retrogrades in development. The different degree of this checked or retrograde metamorphosis, depending on its different application, conditionates the difference of its anatomical development. In many male individuals it completely disappears ; in others it remains an useless relic of a rudimentary character, while in others it assumes a more considerable size and development.\nThe form of the receptacle of the embryo, which, despite many varieties, is in general very constant, is connected with its functional import. But the Weberian organ is devoid of so specific an object. What wonder, then, that we find it more freely submitted to the play of the formative process, and that its form and development are even subject to manifold varieties in particular individuals ?\nThe theory of Weber at once gives us a sufficient explanation of the different anatomical circumstances of this notable organ ; and in like manner it affords a new and secure basis for the efforts of anatomists to determine the analogy \u2014 i. e. the common plan of structure\u2014of the male and female organs.\nEver since Aristotle and Galen, vain attempts have been made to discover an indication of the uterus in the male of the Mammalia; and sometimes this structure, sometimes that \u2014 now the vesicula seminalis, and now the prostate \u2014 has been thus regarded. The explanation given by Weber offers the first satisfactory adjustment, and at the same time promises a sufficient interpretation of the numerous hermaphrodite misdevelopments, or of androgyny. Weber even hints at this (and independently of him Bergmann also), while he subjects the well-known case of Ackermann* to a morphological analysis-j-, although only with the immediate intention of further supporting his explanation of the vesicula pro-statical He came to the conclusion that the\n* Infantis androgyni historia et iconographia, Jen\u00e6, 1805. See also Art. Hermaphroditism, Yol. II. p. 709.\n+ Zus\u00e4tze, loc. cit. S. 13.\npart described by Ackermann as a cystoid uterus, the opening of which into the urogenital canal was situated close to the efferent apertures of the vasa deferentia, was due solely to a disproportionate enlargement of the vesicula prostatica.\nUnder such circumstances it is easily explicable why the theory of Weber has received a very general assent. Huschke, Theile, Hausmann, Bergmann, Leydig, and the author in Germany, Duvernoy in France, and Adams in England, have all accepted it, and have sought to give it further stability by new researches. And Leydig * has further shown that the type of the glands imbedded in the wall of the Weberian body completely corresponds with that of the uterine glands in the respective female animals.\nH. Meckel f only has expressed himself against the interpretation of Weber, although he so far agrees with it as also to see in the vesicula prostatica a rudimentary structure of chiefly morphological import ; but he explains it as being the analogue, not of the uterus, but rather of the vagina. The chief support which he adduces of this theory is the relation of the Weberian organ to the vasa deferentia and the urethra.\nIt is well known that the older anatomists regarded the vasa deferentia as the structures which, in the female individual, discharge the functions of the Fallopian tubes. Even Weber partook of this opinion, although Muller j had already shown the morphological differences of the two in birds, and Rathke \u00a7 in snakes. That this holds good of Mammalia was first maintained by Bergmann || and the author of this article f, on the ground of their comparative researches; and it was afterwards reduced to certainty by the observations of Kobelt** on the development of the genitals in the human subject. As M\u00fcller and Rathke had previously found, Kobelt showed that, at an early date of embryonic life, tubes and seminal ducts exist simultaneously in all individuals, but that, in the different sexes, only one of these canals attained a complete development.\nIf the seminal and Fallopian tubes were identical structures, the Weberian theory of the morphological nature of the vesicula pro-statica could not possibly be correct; for, in that case, the former of these must constantly open into the upper end of the vesicul\u00e6, or into its two cornua respectively, which is never the case. But now that we know the difference of these two canals, the anatomical arrangement of the vasa deferentia and Weberian organ no longer constitutes an objection against the explanation of the latter as the uterus.\n* Opus cit. S. 49.\nj- Zur Morphologie, &c., S. 47.\nX Bildungsgeschichte der Genitalien. Bonn, 1830.\n\u00a7 Entwickelungsgeschichte der Natter, S. 212. K\u00f6nigsberg, 1839.\n|| Op. cit. in Wagner\u2019s Handw\u00f6rterbuch.\nZur Anatomie, &c., S. 90.\n** Der Nebeneierstock des Weibes. Heidelberg, 1847.","page":1424},{"file":"p1425.txt","language":"en","ocr_en":"1425\nVE SIC UL A PROSTATIC A.\nBat it is not on this that Meckel chiefly relies. He conspicuously brings forward another argument. He states that, if with Weber we regard the vesicula prostatica as the uterus, and its opening as the os tinc\u00e6, we must in consequence consider as the vagina the beginning of the uro-genital sinus, into which open, beside the vesicula, the ejaculatory ducts and the urethra ; a view which has often occurred to the author of this article. But, in the female .Mammalia, the vagina never receives the urethra. This is always inserted at the outer border of the vagina, where it passes into the short and sinus-like dilatation of the uro-genital canal ( vestibulum, atrium vagin\u0153), so that the vagina always lies internally to the aperture of the urethra.\nIts relation to the vasa deferentia is exactly similar, as the history of their development proves that they are originally the efferent ducts of the Wolffian bodies. It is true that these latter generally disappear in the female mammal, but here and there some relics of them are left. This is especially the case in the female ruminant and pig, where they are known under the name of Gartner's canals. Here also they open, never into the vagina, but into the ductus uro-genitalis, together with the urethra. So that in all cases, after the points of opening of the urethra and vasa deferentia, the vagina comes next interiorly. And in the male mammalian the Weberian organ has this situation : it is therefore, concludes Meckel, the vagina, and not the uterus.\nWhile I allow the correctness of the facts brought forward by Meckel, and while,\u2014 against my own earlier opinion,\u2014 I have some scruples as to the unconditional accuracy of Weber\u2019s explanation, yet I cannot approve of Meckel\u2019s conclusion. The form of the Weberian organ, the bifurcation at its upper end, which occurs in so many instances, even its being imbedded in a transverse fold of peritoneum (corresponding to the broad ligaments of the uterus) remind one too closely of the female uterus to admit of the analogy being mistaken.\nNow, in order to reconcile this circumstance with the facts brought forward by Meckel, there remains but two expedients ; either to suppose a complete deficiency of the vagina in the male mammal (in which case the explanation of Weber would be preserved entire), or to set forth the Weberian organ as the morphological equivalent of the vagina and uterus together.\nThe latter of these two acceptations, which I have already defended against Meckel in another place*, finds its full confirmation in the observations on its normal and abnormal development. On these grounds it may be advisable to review them briefly in this place.\nFrom the exposition which Rathke f has given us of the development of the vagina\n* Gottingische Gelehrte Anzeigen, loc. cit.\nj- Abhandlungen zur Biklungs- und Entwickelungsgeschichte, Leipzig, 1832, S. 60.\nVOL. IV.\nand uterus, it becomes evident that these two structures at first present the appearance of a common or inseparable tube, the genital canal, which is only afterwards divided into an upper and under section by a different development of its coats, being connected with a transverse dismemberment. One of these is developed into the vagina; the other forms the uterus. At its first formation the uterus is simple: its cornua only begin later, when the tubes enter its cavity.\nNow, if this genital canal sustained a check of development prior to the separation of the uterus and vagina, it would remain as a simple tube, the horns of which would be either not at all or but imperfectly developed : in short, it would be a Weberian organ.\nIn this way the observations on the normal development of the genitals do not in the least contradict the explanation of the Weberian organ as a genital canal (uterus plus vagina). It is true that we can scarcely thence deduce an absolute proof. We find it, however, in the evidence afforded by the pathological history of its development, since we observe that the Weberian organ is there metamorphosed into both of these parts.\nI have already mentioned above, that a knowledge of the Weberian organ is of the greatest importance in the study of herma-phrodism\u2014a study which now requires a fundamental revision in connection with the recent observations on the morphology of the genitals \u2014and especially since the numerous * instances of androgyny for the most part depend upon an excessive development of this structure in the male individual, \u2014 associated with some other abnormal occurrences in the development of the uro-genital canal and the penis, which appear at the same time, according to the law of coexisteii\u00e7e.\nI have now a number of such androgyni before me. They are all goats, in whom this deformity of the genitals is proportionately very frequent. The exterior segments of the genitals (uro-genital sinus and penis) are, in different degrees of development, formed after the female tvpe, i. e. they are checked in their development to male parts; and so also is the Weberian organ ; while instead of ovaries, testicles with epididymes and seminal ducts are present.\nIn one of these, a new-born animal, the Weberian organ forms a very considerable tubular dependency, which opens by an oval and fissured aperture of about 1^ lines in length, close beneath the two vasa deferentia, in the commencement of the short and wide uro-genital canal. (Fig.882.) From thence the Weberian organ ascends for about two inches as a short and wide cylinder, to split at its extremity into two horns of an inch in length. The left horn is hollow in its whole course, but the right only in its lower half. The\n* Another smaller number of androgyni includes female individuals, with excessive development of the Wolffian bodies and their efferent ducts (Epididymis and vasa deferentia). Vide Simpson, loc, cit., p. 707.\n4 Y","page":1425},{"file":"p1426.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\n1426\nvasa deferentia course along the anterior surface of the Weberian organ, and are connected thereto by areolar tissue. Subsequently to the splitting they run along the\nFig. 882.\nInternal Genitals of a Male hermaphrodite Goat, a, a, testicles with epididymis b, b; c, guber-naculum testis; d, d, vasa deferentia with the seminal vesicles; e, vagina; ff cornua of the uterus.\nlower border of the cornua, between the two lamellae of the ala inagna, but soon become continuous with the canal of the epididymis. The testicles have not descended into the scrotum. They lie at the ends of the cornua, the outer coverings of which pass into the sheath of the epididymis. If the vasa deferentia (which are somewhat thickened at their lower extremities, and, at about six lines from their apertures, possess a pair of seminal vesicles which lie more deeply), be removed from the Weberian organ, it will be seen that the lower end of the latter (e) is wider in an extent of nine lines than the segment which lies above it, and is distinguished therefrom by a constriction. By a further examination of the interior at this point, 1 find a transverse fold by which the two segments are still more separated from each other. Although this fold is not a complete os tinc\u00e6, yet it cannot be doubted that the two segments of the Weberian organ, which are limited thereby, are the uterus and vagina ; the less so that they possess different developments of the muscular and mucous membranes, which, in appearance and structure, exactly correspond with these membranes in the uterus and vagina of a new-born female goat;\nin a second individual I remark a very similar form and development of the Webe-\nrian organ : excepting that there is a much more considerable size and capacity, which is due to the adult age at which the animal was killed. But here there is no separation into vagina* and uterus. But, in spite of this, by a comparison with the normal female genitals of an individual of the same age, one will easily be convinced, that the Weberian organ in this instance corresponds to the uterus with the vagina, and not to the former of these only.\t\u2022\nBut this may best be seen in a third hermaphrodite now lying before me (fig. 883.). Here the Weberian organ is so completely separated into uterus and vagina by the development of\nFig. 883.\nInternal Genitals of a Male hermaphrodite Goat, a t of, as in fig. 883. ; g, g, Fallopian tubes; h, urethra ; i, uro-genital canal.\na formal os tinc\u00e6, that it might almost be thought, from the simultaneous presence of the Fallopian tubes |, from the very consider-\n* The hermaphrodite goat figured by Gurlt (Path. Anat. Tab. 22. fig. 3, 4.), and copied by Simpson (loc. cit. p. 300.), exactly resembles this ; only the horns of the uterus were here produced for a great length, because the testicles had descended through the inguinal canals into the scrotum.\nt The presence of real tubes in the so called An-drogyni is very rare, and has perhaps hitherto beer observed with certainty onlv by Mascagni in the bull. (Atti di Siena, vol. vii. p. 201.) What are usually thus called are only the longly produced horns of the uterus. All that lies between the body of the uterus and the Hunterian ligament belongs, to the cornu of the uterus. The tubes always lie, as H. Meckel has pointed out (1. c. S. 43.), on the other side of the Hunterian or round ligament, as is represented in my case by the figure above. At the end of the tubes in this case, there is a small, almost cup-shaped, nodosity at the inner border of the epididymis, which is apparently the imperfectly developed fimbria.","page":1426},{"file":"p1427.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\t1427\nable width of the vaginal orifice, and the almost female uro-genital canal, that we had a true female before us. The testicles (a a), which remain in the abdominal cavity, possess a true ala vespertilionis, and also exhibit a more solid parenchyma than usual, although they consist of spermatic gland-canals. Only the epididymis and vas deferens are distinctly male in character. The latter (d d) takes-the same course as in the instance previously described, except that the lower ends are completely buried in the anterior wall of the body of the uterus and the vagina (like the Gartner\u2019s ducts), and the seminal vesicles are much smaller.\nIn this way we acquire a conviction that tire Weberian organ, by a further development, is formed \u2014 not into a uterus only, nor yet into a vagina only\u2014but, at least as a rule, into both these structures simultaneously. Hence we need not scruple to regard it as the morphological equivalent of both. So that the Weberian organ is the male sinus genitalis, which in the female animal undergoes a further development into the vagina and the uterus.\nIt is certainly an important guarantee for the correctness of this theory, which had been casually expressed for some time by Birnbaum *, and is now\u2014from a communication to me by letter\u2014shared in by my friend H. Meckel, that it had been applied by E. H. Weberf himself, to the vesicula prostatica of the rabbit. From a comparison with the female organs, he came to the conviction, that it represented the uterus with the vagina ; but unfortunately he neglected to extend this view, and in the other Mammalia he regards the vesicula prostatica as only a masculine uterus.\nWe have mentioned above that the lower part of the Weberian organ is occasionally contrasted with the upper, either by an annular constriction, in man, or by a singular width, as in the horse : or that the contrast may be limited to particular individuals, as in the goat, It is evident that this can only be explained as a transverse severance into uterus and vagina, a condition which certainly is never normally completed in the male animal.\nAnd when, as sometimes happens in the horse, the upper section altogether disappears, we need have no scruples in regarding the lower remaining part as the vagina only. % In such instances the theory of Meckel holds good : a theory which was but too widely applied by its founder.\nHence it may be laid down as a law, that the upper part of the Weberian organ, which corresponds to the uterus, and which also shows such great variations in the develop-\n* Beschreibung und Kritik einer eigenthumliche Bildungshemmung. Giessen, 1848, S. 15.\nf Zus\u00e4tze, &c., S. 8.\nj In some pathological instances a vagina exists without an uterus ; as was detailed by Kicco (Cenno Stor. su di un neutro uomo), and quoted by Simpson (1. c. p. 703.).\nment of its horns, is less persistent than the under part of the vagina. Thus the question may arise whether the Weberian organ, when it is devoid of cornua, still possesses an upper or uterine part. In order to decide this with certainty, every such instance would require a careful analysis, assisted by the history of its normal and abnormal development. But as a rule we are justified in supposing that the Weberian organ is, as was stated above, and as is constantly rendered indubitable by the presence of cornua, both vagina and uterus.\nI have here, without further discussion, passed over the question, whether a complete absence of the vagina may not obtain in the male mammalia ; a supposition which is required by the unconditional reception of Weber\u2019s theory. And this has been done because an assumption of this kind only leads to doubtful morphological hypotheses ; the necessity of which seems very inconceivable after the positive results we have already obtained. Wherever the female individual possesses a vagina the Weberian organ is, at least in part, vagina also ; even where, as in the beaver, the exterior appearances speak by no means strongly in its favour.\nBut it is certainly otherwise in the case of those Mammalia whose females lack the vagina. Here I do not so much refer to the mono-tremata, who, in the development of their genitals, approach much more closely to the birds than to the other Mammalia, and perhaps are devoid of a proper uterus : but rather to the elephant, in the female of which, as Mayer has lately shown *, the orifice of the urethra is only separated by a very small fold from the external orifice of the uterus, and the vagina is absent. The whole genital canal is here metamorphosed into uterus. In like manner the Weberian organ of the young male certainly corresponds to the uterus solely. In any case, such instances constitute but rare exceptions, and do not affect the general interpretation of the Weberian organ.\nAfter all that we have now learnt concerning the morphological import of the Weberian organ, it is scarcely necessary to state, that it, \u2014 or rather the embryonic part out of which it is developed in the male animal, \u2014 is present in all mammalia up to a certain period of foetal life. Where it is afterwards absent it must be attributed to a retrograde process of development ; w hich to some extent appears to occur very early, as in the sheep. The date and degree of this retrogression is shewn by the anatomical development of the Weberian organ. In some instances it preserves both its embryonal form and size ; in others it continues to increase even after birth, as was especially mentioned of the rabbit.\nI recur once more to this animal, because it, with its congeners, is not only conspicuous on account of the described connection be-\n* Beitrage zur Anatomie der Elephanten ; in den Nov. Act. Leopold, t. xxii. P. II. S. 38.\n2 Y 2","page":1427},{"file":"p1428.txt","language":"en","ocr_en":"VESICULA PROSTATICA.\n1428\ntween the Weberian organ and the vasa de-ferentia, but also on account of its seeming to constitute an exception to the alleged morphological lav/ that the efferent ducts of the Wolffian glands never open into the vagina, but always into the point of its transition into the uro-genital canal. According to my observations in the embryo of the rabbit, even here the ordinary relation is originally present: the Weberian organ opens close behind the vasa deferentia into the urogenital canal. But very soon a transverse fold arises behind the points of opening of the seminal ducts, and by its continual enlargement, even after birth, it as constantly protrudes these openings outwards into the neck of the Weberian organ. Even in the fully developed condition this fold may be recognised in the anterior swollen margin of the opening of the Weberian organ.\nAddendum.\u2014A considerable period having elapsed since the MS. of the preceding article was placed in the Editor\u2019s hands, I have availed myself, during that time, of many opportunities both of confirming and extending my observations on the phenomena connected with the Weberian corpuscle. My esteemed friend and colleague, the eminent embryologist, C H. Bischoff, has, with great liberality, handed over to me a large number of rare preparations, from the collection of the Giessen University, for comparative examination.\nFrom another source also an important addition to the knowledge of this organ has been afforded us ; and this I hail with the greater pleasure, as it shows how great an interest attaches itself to this subject in other countries. The treatise to which 1 allude is the Inaugural Dissertation by Wahlgren, published at Lund.*\nI therefore now find myself in a position to fill up many deficiencies in the foregoing paper. For this purpose I prefer the form of a supplement, and hope that the reader will excuse whatever degree of inconvenience attaches itself to it, on account of the circumstances under which a foreign contributor is situated.\nQuadrumana. \u2014 I formerly conjectured that the true Apes, without exception, possessed the Weberian organ (p. 1416.) ; in confirmation of this, I can now add, that it occurs both in the species mentioned (toe. cit.), and in Pilhecus troglodytes and Cynocephalus por-carius. Wahlgren observed it likewise in an undescribed species of Ape. It appears, however, not to occur throughout the group in an equal manner. In the Lemur aUnfrons, I observed on the colliculus seminalis a fine longitudinal fissure, between the apertures of the seminal ducts (a fine capillary canal entered it a short distance \u2014 but this may have been\n* Eidrag till Generations-Organernas A natomi och Physiologi hos Menniskan ocli Daggdjuren, 1849. Translated by Peters into German, in J. Muller\u2019s Archiv f\u00fcr Anatomie und Physiologie, 1849, S. 686., et seq.\nmade in mounting the preparation): in Slenops tardigradus I have, however, convinced myself of the absence of the organ.\nFerce.\u2014 Wahlgren describes the Weberian corpuscle in Felis lynx as an oval cavity, three lines in length, and opening by a fissure-hke aperture into the uro-genital canal on the middle of the verumontanum. In the Brown Bear it is similar, but much larger (d'\"), pear-shaped, and with a considerable aperture. Nasua fusca, also, according to Wahlgren, possesses a similar gland. In the Otter, I have now observed this organ in two specimens. It is disposed as the foregoing, and; as was conjectured, has a considerable central cavity, with a small aperture. The cornua are solid ligamentous cords.\nMarsupialia. \u2014 The marsupial animals appear to be very generally destitute of this organ. In Halmaturus giganteus, Phascolomys wombatus, and Sarcophilus ursinus, I found no more traces of it than previously in Didelphys virginianct. Wahlgren also found it absent in Halmaturus giganteus.\nRodentia. \u2014 The remarkable structure of this organ in Rabbits and Hares might well belong to the whole group of the Leporin\u00e6. In Lepus borealis it is the least, c\u00e6terisparibus, according to Wahlgren. Yet here it attains even the colossal size of three inches, with a proportionate breadth (up to KP\"). With the Palmipedia, on the contrary, it is otherwise. Distinct as it is in the Beaver (p. 1418.), it is but little developed in the nearly relatedMyopotamus coypus, in which Wahlgren found a mere rudiment, consisting of two thread-like cords. The two agreed in their position with the Weberian corpuscle of the beaver, and enclose a small cavity, with an opening on the colliculus seminalis. With regard to Sciurus, Wahlgren confirmed the absence of the organ : nor was it observed in Lemnus. Hystrix crista fa and Hydroch\u0153rus cnpybara are likewise without it, according to my own observations. In the last, however, as in the closely allied Agouti and Cavia, the two seminal ducts have a common, cavernous, wide aperture.\nEdentata. \u2014 Besides the Bradypus iridac-tylus, I have lately examined Chol\u0153pus didac-tylus, also Dasypus octosus, and Ornithorhyncus paradoxus. In none of these is the organ present. Wahlgren also states the same of Ornithorhyncus.\nRuminantia. \u2014 The Weberian organ appears to be generally present in the Cervina. That of the deer is above described (p. 1420.). It is far moreconsiderable in the Hart and the Reindeer, where it ascends between the seminal ducts in the form of a cylinder, about two inches long, which in the former is distinctly, bi-cleft at the extremity. There is an internal cavity, which in the Hart is continued into the cornua, and opens on the verumontanum. In the Goat there are numerous individual varieties in the development of this organ, as I have before mentioned (p. 1420.). In many instances it is altogether wanting, as I have now convinced myself. In one case I","page":1428},{"file":"p1429.txt","language":"en","ocr_en":"VESICUL\u00c6 SEMINALES.\nsaw it in the form of a single longish body (3W), between the vasa deferentia; in another it continued upwards as a long solid cord, which adhered by its bifurcate extremity to the seminal ducts. In both cases it had a distinct opening. The wide differences in the development of the organ above mentioned, are of rare occurrence.\nAs regards the Sheep, the absence of the Weberian corpuscle in the perfect form has been already stated. According to Wahlgren, however, such is the case (as in the Goat) in isolated individuals only; whilst in others, on the contrary, a small purse-shapecl body represents this organ.\nWahlgren describes this organ as occurring in the Bullock in the form of a flask-shaped sac, 6-7,// long. That here also many varieties occur (as pointed out by my observations), is evident, for in another (castrated) animal it was present as a short uniform canal.\nCetacea.\u2014In a young specimen of Delphinus delphis (so labelled), I now find, as already stated in regard to other species, two thick, cleftshaped, closely approximate pseudo-representations of this organ. The examination of the Halicore dugong was of particular interest to me. This animal, belonging to the group of herbivorous whales, possesses a Weberian organ, having a small roundish (and bordered) opening on the colliculus seminalis. Its form and size cannot be accurately determined on account of the condition of the preparation ; it appears, however, to be about an inch in length, and in shape like a wide longish bottle.\nA peculiar structure here distinguishes the commencing portion of the uro-genital canal. Instead of exhibiting a direct continuation of the urethra, it begins with a peculiarly wide cavity, which is bent outwards like the belly of a retort, and receives the urethra (under wh\u2019ch the large colliculus seminalis rises prominently) on its hinder wall. I know of only one male mammal that presents a similar structure, viz. the Hedgehog ; nor in this case is the disposition of parts so remarkable. When, therefore, Wahlgren asserts that this cavity at the commencement of the uro-genitui canal in the Hedgehog is the Weberian organ, he is in error ; as is proved by the co-existence of both of these peculiarities of structure in the Dugong.\nIn reference to the morphological signification of the organ in question, Wahlgren completely agrees with me. He also views it as the representation of the whole female sinus, that is, the uterus and vagina taken together.* We must not forget that, as we have already observed, the latter of these two parts finds\n* Still more recently, on the contrary, Yan Deen affirms (Zeitschrift f\u00fcr Wissenschaft!. Zoologie v. Siebold und K\u00f6lliker, 1849, S. 268.), also Betz (M\u00fcl-ler\u2019s Archiv, 1850, S. 65.), that the Weberian organ is exclusively the \u201cuterus masculinus.\u201d We do not here again enter into a critique of this view, and must refer our readers to our former remarks. We must mention, however, that the fii\u2019st of these articles contains very numerous errors, and many odd hypotheses.\nH29\na complete and general representation in this organ. This especially applies to the simple form of this organ, when it occurs as a mere oval body without upward continuations of the cornua ; and among others, to the human utriculus, which, on that account, in the case of an abnormal enlargement, becomes merely a vagina. Steglehner has already remarked* on this subject, that the so-called uterus cys-todes of Ackermann\u2019s well-known hermaphrodite case (Art. Hermaphroditism, Vol.II. p. 709.), answered, not to the uterus, but the vagina. I have been led to the same results by the examination of a great number of human hypospadiacs and hermaphrodites. A true uterus, as in the single case of May erf, is indeed only seldom found on such a vagina. The vasa deferentia pass constantly on the anterior wall of this vagina, and open near it in the uro-genital canal, like Gartner\u2019s canals in the Ruminantia. They are never connected with the vagina itself, as Hyrtl has observed.\n(Rud. Leuckart.)\nVESICUL\u00c6 SEMINALES. \u2014 These are a pair of sacculated organs, peculiar to the male, situated behind the bladder, between it and the rectum. In man they appear, externally, as multilocular cysts about two inches in length and three quarters of an inch in their greatest breadth. Their shape is fusiform ; their larger ends diverging from one another, and their smaller ends converging so as almost to meet. These smaller ends are surrounded by the prostate, and are directed slantingly forwards, as well as downwards and inwards. Along their inner sides pass the vasa deferentia, with which they join, by a narrow outlet, at the base of the prostate.\nThe vesieu\u00ee\u00e6 are invested by a fascia derived from the prostate, which can be removed by careful dissection, and then they are found to consist of a blind tube of about the calibre of a small goose quill doubled upon itself again and again, all the gyrations being held together by cellular tissue, so as to give the appearance of fusiform multilocular sacs. A little careful maceration will enable the anatomist to unravel these gyrations, when each vesicula will sometimes be found to be one simple caecal tube about six or eight inches long, or, more frequently, there will be three or four caecal diverticular appendages to the main tube, in which case the greatest length (that of the central main tube) will be very much less. This tube has a very much smaller calibre for a short distance from its junction with the vas deferens than elsewhere. The narrow portion is straight, and is commonly called the duct of the vesicul\u00e6 s\u00e9minales.\nThese vesicles are found to contain a synovia-like brownish mucus, the nature of\n* De Hermaphroditorum Natur\u00e2. Bamberg\u00e6, 1817, p. 97.\n+ Vol. II. Art. Hermaphroditism, fig. 303.\n4 v 3","page":1429},{"file":"p1430.txt","language":"en","ocr_en":"1430\nVESICUL\u00c6 SEMINALES.\nwhich we shall have to inquire into presently, when we treat of their function.\nThe fascia that invests the mass of gyrations, like a fusiform bag, contains a great proportion of involuntary muscular fibre, and there is also a large admixture of involuntary fibre in the proper parietes of the tube. It is, of course, lined throughout with a mucous surface, which has a faint reticular marking, like that of the stomach in some animals, and is evidently glandular, or secreting.\nComparative Anatomy.\u2014Some consider able difficulty has been experienced by comparative anatomists in identifying the vesicul\u00e6 s\u00e9minales in different animals. This has given rise to much discrepancy as to their existence, or non-existence, in certain species. In the Muminantia, for instance, the prostate assumes the very singular form of two organs, each having a large central cavity opening into the urethra by a single duct ; and these organs, very naturally, have been regarded by some as vesicul\u00e6 s\u00e9minales. Who, indeed, ean undertake to say, with certainty, that they are not ? It is far from improbable that they are both the one and the other \u2014 prostate and vesicula at once.\nThere are two very distinct kinds of comparative anatomical identity\u2014functional identity and homological identity. Instances are very numerous of homologically identical parts being very diverse in function ; the function of the (homological) hand, for instance, is to seize with in man, to walk with in the horse, to fly with in the bat, and to swim with in the whale. And there are not wanting many instances of parts functionally identical, and homologically diverse ; a striking instance of which is furnished by the urinary bladder in Mammalia, compared with the reservoir of urine sometimes met with in Ovipara. In the case now before us, the function is in question, and the homology by no means prononc\u00e9 ; no wonder then that identification should be difficult and uncertain. We proceed, however, to notice the various forms of certain sacs met with in brute animals, posited in close relation to the vasa defe-rentia, and impressing one somehow, perhaps homologically, with a notion that they are identical with the human vesicul\u00e6 s\u00e9minales.\nSuch vesicul\u00e6 are exclusively confined to the placental division of the Mammalia. They are not met with in the Marsupialia nor Monotremata, nor in the other vertebrate classes, \u2014 Aves, Reptilia, nor Pisces. In some of these, Aves for instance, there are undoubted reservoirs of semen, formed by dilatations of the vasa deferential these, however, are manifestly not the organs in question.\nReservoirs of semen are also met with in some Invertchrata, but since, as I have elsewhere noticed (Art. Symmetry, Vol. IV., p. b50.), homological identity of parts can in no instance be established in animals belonging to different sub-kingdoms, the only identity being in all cases merely that of function, these have no title to be described in an article on the vesicul\u00e6 s\u00e9minales, from w'hieh\nby function they are, as will be seen hereafter, for certain diverse.\nThey are indubitably present in all the Quadrumana, the Cheiroptera, and the Insecti-vora. They are wanting in the Carnivora. Present in the Rodentia, and Pachy der mata, and in the Manatee. In the other Cetacea they are absent. In the Ruminantia, the questionable organs, mentioned above as hollow prostates, occur.\nIn the higher Quadrumana they much resemble those of man ; and their ducts join the vasa deferentia much in the same manner as in the human subject. In most of the lower monkeys they have not the convoluted form, but occur as simple sacs, and the outlets, at the side of the verumontanum, alone are common to their ducts and the vasa deferentia. In Galeopithecus they are remarkably small.\nIn the hedgehog their size is enormous \u2014 twice that of the vesicul\u00e6 in man \u2014 and they have a very interesting form. They consist each of a small central duct, from which ramify very numerous convoluted caeca of much greater calibre. The central duct terminates on the verumontanum, near the vas deferens.\nIn the Rodentia they are, mostly, very large. In the rabbit and hare they are, apparently, fused together, and form a single mesial sac, the upper end of which is somewhat square, thick and glandular. This sac opens by a mesial orifice, which receives the vasa deferentia, upon the verumontanum. It is, however, very improbable that this really (homologically) represents the vesicul\u00e6 s\u00e9minales ; its mesial position, between the vasa deferentia, is essentially different from that of the vesicul\u00e6, which is always external to those ducts. It is most probably the utriculus prostaticus. In the other Rodents they are double ;\u2014long, simple, and bi-fusiform in the guinea pig; serrated in the rat; having small ramifications in the agonti; and convoluted in the beaver. In the squirrel they consist of a small tube with glandular parietes, and much convoluted. In the Alpine marmot they are but slightly developed, very convoluted, and have glandular parietes. In all these their outlets are quite distinct from, though near to, those of the vasa deferentia.\nIn the Pachydermata they assume very various forms. In the genus Equus they resemble two small urinary bladders, anti have two distinct muscular coats. They are thicker at their fundus than elsewhere; the thickening consisting of a glandular substance. The orifice of their ducts is in common with those of the vasa deferentia. There is also, in this genus, a third vesicular organ, situated me-sially between the vasa deferentia, of a long cylindical form, with a rounded fundus, and secreting a substance of the consistence and colour of honey. This is, undoubtedly, the homologue of the utriculus prostaticus. In the Hyrax they are very large and convoluted. In the Rhinoceros they consist of two large irregular sacs, whose excretory ducts join the vasa deferentia. They are very large in the elephant, of an oval figure, with a constriction at their upper end. Their internal surface is divided by","page":1430},{"file":"p1431.txt","language":"en","ocr_en":"VES\u00cfCUL\u00c6\nirregular columns and grooves, more marked in their upper part, and deficient at the lower. On their outer and anterior aspect is a peculiar muscle, arising from their neck and middle portion, and spreading out over their upper part, which can contract their cavity and expel their contents. Their ducts join the vasa deferentia beneath their ampullated portion noticed below. In the boar they each consist of a great number of lobes and lobules arranged around, and communicating with, a small central canal, which opens on the veru-montanum, near the vas deferens.\nIt may not be out of place here to mention several remarkable peculiarities in the structure of the vasa deferentia, when they arrive at the back of the bladder, in several animals. In man this part of them is dilated and sinuous, and generally contains a fluid very similar to that found in the vesicul\u00e6. In the horse this part of the ducts is extremely thickened by the occurrence of numerous glandular cellules in its walls. These cellules contain a thick mucus. Much the same condition is met with in the bull. In the elephant each vas deferens, when it arrives at this part, enlarges into a very large cavity, which it is evident may readily, and no doubt does really, fulfil the function indicated by the words vesicul\u00e6 s\u00e9minales.\nFunction. \u2014 With regard to the function of these organs, I am able to come to little more than a confimation of the negative conclusion of Hunter, that they are not reservoirs of semen. Hunter\u2019s positive conclusion that they form part of the generative apparatus, is pretty clearly proved. I proceed to offer the evidence from which these two conclusions are arrived at.\n1st. They are not reservoirs of semen. That they were receptacles into which the semen might regurgitate and be stored up ready for emission, was doubtless suggested by their connection with the vasa deferentia in the human subject, so like the relation of the gall bladder to the hepatic duct. A very obvious objection to this is that, as we have seen, the same relation does not occur in the majority of animals ; but the difficulty of proving the identity of the sacs called vesicul\u00e6 in other animals, diminishes very much the force of this objection ; and even if a homological identity were proved, still numerous caveats warn us not therefrom to infer their functional identity. It is moreover extremely easy to conceive the possibility of the regurgitation of semen into the vesicul\u00e6, where the two ducts have an outlet, though merely an outlet, in common. ( In such cases they join just in the act, so to speak, of debouching.) And it is far lrorn impossible to conceive the regurgitation of semen even when the outlets are distinct, especially in some instances. In the guinea-pig, for example, the outlets of the vasa deferentia, vesicul\u00e6 s\u00e9minales, and prostatic ducts, are surrounded by\u2014occur in the bottom of\u2014 a little spout, of about a line in diameter, which projects about half a line into the urethra, slanting towards the outlet. Another\nSEMINALES.\t1431\nobjection to their being reservoirs of semen is that the fluid found in them is extremely different from that found in the vasa deferentia, as observed by Hunter, in colour, consistence, and smell ; but that they should secrete a mucus of their own, is only parallel with what we know to be the case in the gall bladder ; and that admixture with this mucus should considerably alter the character of the semen, is extremely probable. To a microscopic examination of the contents of the vesicul\u00e6, we naturally look for a solution of this question, now that we know the extremely characteristic microscopic appearance of semen \u2014Are spermatozoa found in it ?\nMuller says \u201c That the vesicul\u00e6 s\u00e9minales are really receptacles of semen, is beyond a doubt, since spermatic animalcules have been discovered in their contents in the human subject after death.\u201d * To the fact, that spermatozoa are occasionally found in the contents of the vesicul\u00e6, I can add my testimony ; but I am compelled by other facts to dissent from the conclusion at which Miiller arrives. To infer that the proper function of the vesicul\u00e6 is to serve as reservoirs of semen, because spermatozoa \u201c have been\u201d found in them after death, is a non sequitur. Spermatozoa may often be found in the urethra, and I have found them in the urinary bladder. These restless little entities often wriggle themselves into organs where their presence is far from usual or normal. Even after death they may be forced into the the vesicul\u00e6 by the violence unavoidable in removing the parts for examination. The question is, are they usually found in the contents ot the vesicul\u00e6, and that in large numbers ? To answer this question I thankfully avail myself of the more extensive observations of my friend, Mr. J. Quekett, who carefully examined the subject some years ago. He tells me that the presence of spermatozoa in the human vesicul\u00e6 is not very frequent, even when the sacs are very distended by their contents ; and that when they are present, it is in sparing numbers \u2014 in fact, as a few stray ones. This accords perfectly with the results of my own researches.\nWhen I find the vesicul\u00e6 s\u00e9minales full to distension with a mucous fluid, and discover, by a microscopic examination, only a few solitary spermatozoa in it, and when I compare this with the crowds of spermatozoa seen in the fluid squeezed from the vas deferens, I cannot believe, even allowing a reasonably broad margin for dilution with mucus, that 1 am examining stored semen. In the lower animals I have never observed a single spermatozoon in the contents of their vesicul\u00e6 s\u00e9minales, although I have carefully examined it taken from individuals that had been purposely subjected to prolonged sexual excitement ungratified. My observations, however, have been entirely confined to those brute animals the ducts of whose vesicul\u00e6 do not join the vasa\n* Physiology. Translation by Baly, p. 8484.\n4 Y 4","page":1431},{"file":"p1432.txt","language":"en","ocr_en":"VESICUL\u00c6 SEMINALES.\n1432\ndeferentia, which, as may be seen by reference to the comparative anatomy cited above, is the case with all the lower animals readily procurable, alive, and in functional activity, in this county. The best evidence that comparative anatomy affords on the subject is, that, in the elephant, vesicul\u00e6 s\u00e9minales, joining the vas deferens just as in man, coexist with unmistakeable seminal reservoirs. If the vesicul\u00e6 were merely receptacles of semen their presence here would be quite supererogatory, and contrary to Nature\u2019s usual fashion. It adds to the signification of this fact, that the junction of the ducts occurs below the enormous ampulla, that is, between it and the urethra ; so that the ampulla must be filled before any semen could be regurgitated into the vesicul\u00e6.\nStill, as spermatozoa are occasionally found in the human vesicul\u00e6 s\u00e9minales, microscopic evidence, of itself, is not able to give us that complete negation of the old and widely spread view of the functions of the vesicul\u00e6 which I have ventured upon above. And here the acute observations, unaided by the microscope, of the immortal Hunter, of themselves sufficient to prove this negation almost to a certainty, afford such an accession of proof as cannot fail to be convincing. He examined the vesicul\u00e6 in several subjects in which one testicle had been extirpated a long time before death, and he found in every case that the vcsicula of the castrated side was as full as that of the other. One of the cases examined by him was a married man in whom he had extirpated the left testicle a year before his death. \u201c On examining the body, the vesicul\u00e6 were both found nearly full, more especially that on the left side, which might have been accidental.\u201d To remark that the vesicula of the castrated side wras fuller than the other seems to be proving too much (he observed the same in one other case) ; but the rest of his cases show clearly that this was, as he says, accidental. These invaluable observations of Hunter, together with his comparison of the thick brownish mucus found in the vesicul\u00e6, with the extremely different, milky, slightly viscid semen in the vas deferens of the same subject, and the contrast observable in the two fluids by aid of the microscope, \u2014 a few scattered spermatozoa or none at all in the one, crowded mjriads in the other, \u2014 lead irresistibly to the conclusion that the vesicul\u00e6 s\u00e9minales are not reservoirs of semen.\n2dly, They form part of the generative apparatus. This is pretty clearly \\ proved by Hunter, by observations made on those animals that have periods of rut or sexual excitement alternating with periods of sexual quiescence or impotency, such as the stag, the mole, and the land-mouse. In these animals the vesicul\u00e6 s\u00e9minales, in common with the testicles, prostate gland, &c., are exceedingly small during the period of impotence, and enlarge enormously and rapidly for the season of rut. In the mole they are hardly discernible in winter, but become enormously largein spring. Conclusive, however, as this proof appears, prim\u00e2 fade,\nto be, it is somewhat weakened by the fact that much the same thing happens, in various animals, to other parts which would scarcely be enumerated as belonging to the generative apparatus, such as the horns of the stag, the comb of the cock, &c. Yet, adding to the fact of this periodic enlargement and diminution the anatomical position and connections of the vesicul\u00e6, together with their absence in the female, there is constituted a very satisfactory proof that they form part of the male generative apparatus.\nThese conclusions, however, merely bring us two steps nearer to a definite knowledge ot the exact office fulfilled by the organs in question. I now proceed to adduce such other observations as I have been able to make, or have found upon record, as may aid in forming an hypothesis as to their positive function, or may appear interesting.\nThe mucus found in the vesicul\u00e6 is, as will readily be admitted from what has been said above, undoubtedly secreted by their glandular parietes. This is still better proved by a case of Hunter\u2019s, where, as a congenital defect, they had no outlet (nor inlet), and yet were full of mucus. This case shows also that they have the power of re-absorbing their secretion, or at least renders it highly probable. A mucus in all respects similar is usually found in the part of the vas deferens immediately contiguous to the junction of the duct of the vesicul\u00e6. This is very probably secreted by the walls of this part of the vas \u2014 in the horse there is no doubt of it. The mucus of the vesicul\u00e6 is very- thick and viscid in all animals, but more so in some than in others. I have examined it carefully in the guinea-pig, in which animal it is remarkably thicK ; but there is a difference, in this respect, between that which is near the outlet and that which is at the fundus, it being thickest in the former position and gradually thinner towards the latter. It is transparent, granular, and has a faint opaline blue colour. I found that it rapidly solidified upon being squeezed out of the vesicul\u00e6,' and that too even when not exposed to the air and when not subjected to any remarkable diminution of temperature, when lying, in fact, in the urethra of the animal just killed. The mucus contained in the vesicul\u00e6 also solidified more though slowly \u2014 that in the fundus most slowly, and the rest in gradual progression up to that near the outlet. In opening the abdomen of a guinea-pig, it is almost impossible to avoid compressing the vesicul\u00e6, and probably from this cause a considerable quantify of the mucus is forced into the urethra, where I always found it forming a solid mass as hard and elastic as the cartilage of a ray-fish, and moulded to the shape of the urethra : this w ithin a few minutes after the death of the animal. Now, this is just the contrary to what, according to Hunter, is the case with emitted semen, which becomes more and more fluid under exposure. I was, however, highly interested to observe that if the vasa deferentia and vesicul\u00e6 be compressed at the","page":1432},{"file":"p1433.txt","language":"en","ocr_en":"1433\nVESICUL\u00c6 SEMINALES.\nsame moment, so that the mucus and semen shall mix in the act of escaping into the urethra, and they do mix in a remarkably perfect manner in the little spout-like verumon-tanum of the guinea-pig, then the immediate solidification of the mucus does not occur. Whether this curious effect of their mixing is due to the mechanical whipping of the spermatozoa or to a specific solvent power for mucus in the semen, must remain undetermined at present.\nThe degree of liquefaction produced seems to be much greater than what would be due to simple admixture, that is to say, it is much greater than would be produced by adding a drop of watei equally small to a mass cf gum, for instance, equally thick and equally large. This throws fresh light on some observations of Hunter\u2019s, made upon guinea-pigs. He killed a male (which, by the way, he had castrated on one side six months before), immediately after it had copulated, and he found the vesicul\u00e6 of both sides full. He also killed a female immediately after she had received the male and \u201cexamined with attention what was contained in the vagina and uterus ; in neither,\u201d he remarks, \u201c could I find any of the mucus of the vesicul\u00e6, which from its firmness must have been easily detected.\u201d He regards these facts as proof that the contents of the vesicul\u00e6 are not emitted in copulation; but that part of the proof based on the non-detection of thick mucus in the vagina and uterus is, of course, much weakened by the fact of the liquefying property of the semen. The other part of his proof, derived from the fullness of the vesicul\u00e6 immediately after coitus, is, perhaps, answered by the following observations. The vesicul\u00e6 are never found empty\u2014except when they are diminished during the periodic rut in certain animals \u2014 inflict they seem to all appearance equally full at all times, but here no doubt appearances are dec\u00ab itful ; they contract and expand according to the volume of their contents, so that they are never flaccid, and always appear to be as full as they can be. I have observed them exceedingly full and large in an animal just killed, and have watched them contracting under, the stimulus of exposure to cold air, and when nearly the whole of their contents have been expelled by the contraction, they have still appeared, to be quite full,\u2014I should have considered them to be so if I had not actually seen them expel their contents. It is evident that the whole contents of the vesicul\u00e6 are not emitted in one copulation, but there is strong reason to believe that a part is.\nThe semen which can be squeezed from the vas deferens is milk white anil has very little if any viscosity. Now Hunter describing emitted semen says, \u201c the semen first discharged from the living body is of a bluish white colour, in consistence like cream, and similar to what is found in the vasa deferentia after death (?); wfiiile that which follows is somewhat like the common mucus of the nose but less viscid. The semen becomes\nmore fluid upon exposure to the air, particularly that first thrown out.\u201d Here then is a mucus, which very probably is from the vesicul\u00e6. 1 am convinced that it does not exist in the semen of the vas deferens.\nThe mucus of the vesicul\u00e6, examined in the guinea-pig, is not soluble in water. The urine of the animal seems to solidify it in an extreme degree, for if a little of it gets into the urinary bladder it becomes as hard as spermaceti. Boiled in water it shrivels up slightly, but is not in the least degree dissolved. I dissolved it by repeated boiling in solution of potash, by which means I procured a perfectly limpid, colourless solution. This ) fielded no precipitate on the addition of acetic acid. In neither of these respects, therefore, does it differ much from the ordinary varieties of mucus. (See Art. Mucus, Yol. 111. p. 482) Submitted to microscopic examination, I have found it to consist of a very sparing quantity of fluid, in which are suspended little conglomerated masses of transpat ent solid, just visible by the naked eye. The majority of these are of a pretty uniform volume, and appear, when magnified fifty diameters, about the size of duck shot; there are, however, much larger ones and much smaller. Their general contour, whether they be large or small, is spherical, and they have a nodulated, mulberry-like surface, as if composed of smaller balls. The smaller component balls have also an irregular, granular surface, and neither they nor the large conglomerate spheres show any distinct trace of being enclosed in a cell-membrane. 1 have, however, sometimes observed numerous nucleated cells in a portion taken from the fundus of the organ. But often I have sought for these in vain. I have never found them when the vesicul\u00e6 have been exceedingly full and distended, in which circumstances, most probably, secretion would be arrested, and perhaps even absorption going on. These cells are about the size of the smaller (component) spheres. I am tempted by these observations to conclude that the cells I met with were the secreting epithelia of the vesicul\u00e6, and that becoming filled with inspissated mucus (?) they conglomerate themselves into larger spheres. I found it convenient in making these examinations sometimes to add a little white of egg, which produces no alteration in the appearances beyond a greater isolation of the spheres. Yv'hen water is added, the outlines of the spheres become much more distinct, showing a greater difference of refraction of light, and there become percept.ble very numerous insoluble globules, which have a great tendency to coalesce, and appear very much like oil ; their refractive power is, however, less, and there are other reasons for doubting that they are really globules of oil. When semen is mixed with this secretion of the vesicul\u00e6, the spheres are still visible, and the spermatozoa are seen disporting in the fluid between them. No solution of them is clearly detectable. This, however, it should be observed, is when the mixture is exposed to cold, &c. in examination;","page":1433},{"file":"p1434.txt","language":"en","ocr_en":"1431\tVESICUL\u00c6\nit might be different when it is lodged in the uterus or vagina of the female.\nFor reasons given hereafter, I am led to believe that the quantity of actual semen from the testicles emitted at each copulation, is most probably very small, perhaps only three or four drops, at all events not more than the vas deferens is capable of containing. Such an extremely small quantity would be lost in the capacious canal of the urethra, or still more in the enormously capacious canal of the vagina, in the uterus, and in the Fallopian tubes. Some dilution, some addition to the volume, seems necessary in order to obtain an efficient injection of the life-giving fluid. And the quantity actually emitted by a man amounts, by all accounts, to two or three drachms. There has been an addition somewhere. The prostate has doubtless contributed its share, the tiny glands of Cowper theirs, the urethra has given its mite of mucus, more mucus is awaiting in the vagina, and 1 believe that the vesicul\u00e6 are not behind in adding a portion of their hoard of ready-formed mucus to the general stock. The spermatozoa huddled and crowded in countless millions in the vas deferens are now able to disport themselves at ease in the congenial medium ; and the number contained in a few drops of pure semen would be sufficient to people abundantly several drachms of fluid.\n1 am induced by these considerations to form the hypothesis that the office of the vesicul\u00e6 is to secrete, and keep in store, a mucus of such a nature as is congenial to spermatozoa ; which answers the simple purpose of diluting the semen secreted in sparing quantities by the testicles. By diluting I mean merely increasing the volume, not liquefying; for the mixed fluid is more viscid than pure semen. This hypothesis I would, however, have regarded as only provisional until more satisfactory evidence is obtained. It is the only one which the facts at present known warrant. One is much inclined to doubt that so singular an organ as the vesicul\u00e6 is devoted to so simple a purpose. The prostate is generally believed to perform an exactly similar office ; and one is still more loth to believe that two organs so different in appearance as the prostate and vesicul\u00e6 have an identical function. But as I have advanced this hypothesis I proceed to defend it on these and other points.\nThat organs, having the air of being very important, are sometimes engaged in performing a very simple and subordinate function, is instanced by the salivary glands, which afford also an example of several distinct organs fulfilling exactly the same purpose : \u2014 the parotid, the submaxillary, the sublingual, and the numerous little buccal glands, all engaged in secreting a moistening and diluting fluid, which is not indispensably necessary. All these salivary glands are, however, very much alike in appearance and structure, whilst the vesicul\u00e6 s\u00e9minales do not in any way resemble the prostate. In reference to the human subject this remark is true, but\nSEMINALES.\nnot as regards many brute animals. In the guinea-pig the prostate is composed of numerous ramified c\u00e6ca, but loosely bound together, and not very small in calibre, and the vesicul\u00e6 really appear as though they were merely a couple of the prostatic c\u00e6ca gigantically developed. The secretion of these prostatic c\u00e6ca is also exactly similar to that of the vesicul\u00e6. Objections to the identity of the functions of two organs, based on the difference of their appearance, are completely answered by observing the enormous difference of appearance of the liver, for example, in vertebrata, compared with the liver of a crab or lobster ; or, what is more similar to the case under consideration, the large and remarkable gland that secretes the egg-shell in the ray-fish, compared with the part which secretes the egg-shell in birds, which is nothing more than just a peculiar villosity of one portion of the oviduct. It is not now my task to enquire into the function of the prostate, I am merely combatting an objection that may be raised to the hypothesis which I am advocating.\nThe question very naturally suggests itself, how is it that the vesicul\u00e6 are absent in several animals of the mammalian class ? In birds and reptiles there is no urethra, no vagina, no uterus for the semen to be lost in : the orifices of the vasa deferentia are brought into immediate apposition with those of the oviducts in the act of copulation ; but in the carnivora, where the vesicul\u00e6 are indubitably absent, the semen has to find its wa}', meandering through all those labyrinths; and in the kangaroo, the wombat, &c., the males of which have no vesicul\u00e6, the vagin\u00e6 of the females are remarkably lon^, double, and singularly crooked (see Vol. III., fig. 138,). The answer to this is, the males of these animals possess a great number of glands (loc. cit. figs. 135, 13\u00dc. and Vol. IV. fig. 875.), pouring their secretion into the urethra, which secretion, not improbably, serves the same purpose of dilution.\nWith respect to the difference of the contents of the vesicul\u00e6 in different animals, so obvious, for instance, in respect of their consistence or viscosity, it should be remembered that we have evidence of a specific relation between the spermatozoa of a given species and the medium in which they are destined to float after their exit from the spermatic apparatus. I allude to the fact noticed in the article Semen (Vol. IV. p. 504.), that the spermatozoa of amarine non-copulating species continue their movements in sea water, but become instantly motionless and dead when treated with fresh water, which has no injurious effect on the spermatozoa of freshwater species. This may, perhaps, also throw light upon the function of other accessory seminal glands. Every copulating species is probably able to supply, from one or several glands, a medium congenial to its own spermatozoa.\nThere is then no special reservoir for semen in the human subject, nor in the great majority of mammalian animals. What then","page":1434},{"file":"p1435.txt","language":"en","ocr_en":"VESICUL\u00c6 SEMINALES.\nbecomes of the secretion of the testicles when it is not used ? Another question also requires to be answered. The semen, as will be seen by referring to Art. Semen, seems to be a highly elaborated secretion. There is none amongst the various secretions of the body that seems to require so much time for its elaboration. Not only have cells to be formed and thrown off, as in the case of other secretions, but, after they are liberated in the tubules of the testis, nuclei have to divide, nucleoli to multiply, and each division of the nucleoli to become, through a gradual adolescence, an adult spermatozoon. This surely requires time ; how can such a fluid be improvised at any moment when copulation may take place ?\nTo the first of these questions I would answer, the testicles do not go on continually secreting, but stop when there is no occasion for their action; as I have convinced myself by observing, that the vas deferens is generally found empty in men who have been long removed from the society of women. Hunter arrives at the conclusion, that the vas deferens and testicles can and do reabsorb the unused semen, and that conclusion it is impossible to avoid, because there are many instances on record of the vasa deferentia being imperforate in a subject whose testicles were in full functional activity. But involuntary emissions in sleep are most probably the usual and natural means whereby the burden of unappropriated secretion is got rid of.\nThe answer to the second question is as follows. There is strong reason to believe thdt man, in common with brutes, is subject to a periodic rut, an alternation of sexual excitement and quiescence, occurring at short intervals. During the period of excitement spermatozoa are becoming rapidly adult, the testicles and their ducts are full of semen, the individual is in the condition of a fish with a full milt, or a bird or stag with enlarged testicles. He now instintively seeks the society of women (these things are not so much matters of chance as is generally imagined, and the testicles may be blameable for much of what is usually ascribed to the heart). Lascivious dalliance increases his excitement, and all is ready for the copulative act. There is reason to believe that one vas deferens alone furnishes the semen for one copulation, the other vas supplies another emission ; but after a few encounters, some of them perhaps without effect, a period of rest is required to secrete and perfect a fresh store of semen. The duct of the testicle is the only reservoir, and for that reason, combined with the unlikelihood of the impromptu secretion of semen, I formed the opinion cited above, that the quantity of actual secretion of the testicles emitted in one copulation is probably so small as to require augmentation by some congenial fluid.\nHunter remarks, \u2014 \u201c We have a presumptive proof that the semen can be absorbed in the body of the testicle and in the epididydi-mis, and that the vesicul\u00e6 secrete a mucus\nwhich they are capable of absorbing when it cannot be made use of. We may likewise infer from what has been said, that the semen is not retained in reservoirs after it is secreted, and kept there till it is used, but that it is secreted at the time, in consequence of certain affections of the mind stimulating the testicles to this action ; for we find that if lascivious ideas are excited in the mind, and the paroxysm is afterwards prevented from coming on, the testicles become painful and swelled, from, we may suppose, the quantity of semen secreted, and the increased action of the vessels, which pain and swelling is removed immediately upon the paroxysm being brought on and the semen evacuated ; but, if that does not take place, the action of the vessels will still be kept up, and the pain in the testicles in general continue till the paroxysm and evacuation of the semen is brought on, to render the act complete ; without which a stop cannot be so quickly put to the action of the vessels that produce the secretion, nor the parts be allowed so easily to resume their natural state. There is at this time no sensation of any kind felt in the seat of the vesicul\u00e6 s\u00e9minales, which shows that the action is in the testicles, and in them alone. The pain in the testicles, in consequence of being filled with semen and,' of the action being incomplete, is sometimes so considerable as to make it necessary to produce an evacuation of the semen to relieve the patient.\u201d Hunter was not aware of the highly elaborated character of the seminal fluid, or he would probably not have so readily accepted the idea of the semen being secreted \u201c at the time.\u201d The \u201c lascivious ideas \u201d which he mentions are probably an effect or concomitant of seminal repletion rather than a cause, yet becoming, perhaps, an additional cause in their turn.\nMany interesting arguments in relation to this subject might doubtless be derived from the manner of copulation of different animals; but this is an occurrence in the natural history of species which authors have entirely left unnoticed, probably from feelings of delicacy. This want is felt as a great desideratum by the comparative anatomist, in investigating any of the accessory parts of generation, where the manner of coition unavoidably forces itself upon our consideration, malgr\u00e9 the delicacy, which everybody feels, but which the physiologist is bound to suppress when he handles such subjects. Asa sample of such arguments I may adduce the following. The prolonged coition of the dog, which is destitute of vesicul\u00e6, was formerly much dwelt upon in support of the pre-Hunterian view of tne receptacle-function of these sacs. But is the act prolonged in every animal destitute of vesicul\u00e6 ? I have been told that the copulation of cats is very quickly completed ; and cats are as destitute of vesicul\u00e6 as dogs. On the other hand, the boar is very long in coition, although his vesicul\u00e6 are very large and complicated. Such reasonings on the facts of comparative anatomy","page":1435},{"file":"p1436.txt","language":"en","ocr_en":"14-36\nVISION.\nare, indeed, very unsafe, unless the number of facts observed is very great, and that is not the present condition of our knowledge of the copulative act. For that reason I have not dwelt upon this, prima facie so obvious, line of argument.\nOur knowledge of the function of the ve-sicul\u00e6 s\u00e9minales is, therefore, nearly in the same condition as it 'was left by the great Hunter, whose concise paper on this subject is a master piece of reasoning and scientific acumen. I have been able to add to this, besides confirmation, little more than some few observations tending to render it more probable that the secretion of the vesicul\u00e6 is used in copulation. I have, further, ventured on an hypothesis which, 1 suppose, has suggested itself to many before, and with w hich I am by no means satisfied. So great, however, are the difficulties surrounding the subject, that in this unsatisfactory state\u2014the positive function still hypothetical\u2014I am compelled reluctantly to leave it.\n(S. 1\u00ce. Vittard.)\nVISION. \u2014 ( Fr. vision,from Latin risio, from video, visas, sight.)\u2014The faculty of seeing is one of the chief means by which living creatures are brought into relation with the world around, and is the especial means by which they are enabled to appreciate the wonderful phenomena which flow directly and indirectly from the creation of light. When in obedience to the Divine command, \u201c There was light,\u201d there w ere organs created for its perception ; and it is interesting to observe that the restoration of this gift of perception, when lost, was among the most frequent, and certainly not the least striking of the manifestations of miraculous power displayed by the Saviour of mankind. The vastness of the field over which the faculty of vision gives us command, the precision and permanence of this class of our percep ions, the variety and accuracy of the information it conveys, and the delight it affords, lead us irresistibly to regard it as the most perfect of our senses. In the investigation of this subject a train of minute adaptation and wonderful contrivance is disclosed to us, in which are combined the extremes of grandeur and of delicacy. There is no department of science that possesses a more absorbing interest than the laws of optics when applied to the eye, and certainly none which points with a steadier hand to the wisdom of an omnipotent Creator.\nVery curious and unexpected information respecting the early condition of the surface of this planet and the ancient atmosphere has been afforded by an investigation into the structure of the organs of vision with which the earliest marine animals were supplied. In the eloquent language of Dr. Buckland, \u201c with respect to the waters wherein the Trilobites maintained their existence throughout the entire period of the transition formation, we conclude that there could not have been that imaginary turbid and chaotic fluid, from the precipitate of which some geologists have supposed the ma-\nterials of the surface of the earth to be derived : because the structure of the eyes of these animals is such, that any kind of fluid in which they could have been submerged at the bottom must have been pure and transparent enough to allow the passage of light to organs of vision, the nature of which is so fully disclosed by the state of perfection in which they are preserved. With regard to the atmosphere also, we may infer that had it differed materially from its actual condition, it might have so affected the rays of light, that a corresponding difference from the e}es of existing Crustaceans would have been found in the organs on which the impressions of such were then received. Regarding light itself, also, we learn, from the resemblance of these most ancient organizations to existing eyes, that the mutual relations of light to the eye and of the e3re to light, were the same at the time when Crustaceans endowed with the faculty of vision Mere first placed at the bottom of primaeval seas as at the present moment.\u201d\nLight. \u2014 To the opinions of the ancients on the subject of light but little allusion need be made, as they were but crude and vague conjectures. One, for instance, supposed that the eyes emitted emanations of some sort by which objects were, as it were, felt. Others imagined that visible objects were constantly throwing out from them spectral resemblances of themselves, which, w'hen received by the eye, produced an impression of those objects ; but in these fanciful notions there is little satisfaction, and we proceed at once to the hypothesis of our illustrious countryman, ISir Isaac Newton. According to his theory, light was an imponderable substance, whose inconceivably minute particles produced the sensation of light by their action on the eye : moving with immense velocity, they were nevertheless acted on by attractive and repulsive forces residing in all material bodies, and by these forces were liable either to be turned aside from their natural straight course, reflected by the repulsive force, or penetrating between the particles of bodies, to take a direction on quitting them finally determined by the position of the surface at which they emerged. About the same time, however, a very different hypothesis was advanced by Hujghens, to the effect that all space is filled with an extremely elastic and rare ether, and that light is the result of the undulatory movements communicated to this ether by self-luminous bodies, M'hich movements being transmitted to the optic nerve, give rise to the sensation of light. The beautiful experiments of Dr. Thomas Young strongly confirmed the truth of this theory, which is based upon the supposition that light acts by vibrations upon the retina, in the same manner as the undulations of the air striking upon the tympanum excite the sensation of sound.\nThe velocity of the luminous undulations deduced by R\u00f6mer from the eclipses of the satellites of Jupiter, is proved to be about 192,500 miles in a second: in other Words,","page":1436},{"file":"p1437.txt","language":"en","ocr_en":"VISION.\n1437\nlight travcds a distance equal to eight times the circumference of the earth, between two beats of a clock.\n\u2022 That white light was supposed by Newton to be composed of seven colours is too well known to need description here ; but the proportion of each colour, according to the observations of Newton and Fraiinhofer, is\nas follows : \u2014\tNewton.\tFraunhofer.\nRed -\t- 45 -\t- 56\nOrange\t- 27 -\t- 27\nYe'low\t- 40 -\t- 27\nGreen\t- 60 -\t- 46\nBlue\t- 60 -\t- 48\nIndigo\t- 48 -\t- 47\nViolet\t- 80 -\t- 109\n\t360\t360\nIt is to Sir David Brewster that we are indebted for our knowledge of the fact, that the solar spectrum in reality consists of only three primary colours, red, yellow, and blue ; each of which exists throughout the whole of the spectrum ; and that the super-position of these in different degrees of intensity in different parts produces the seven hues. The proportion in which the primary colours combine to form white light, is: \u2014\nYellow, three parts.\nRed, five parts.\nBlue, eight parts.\nAll the seven hues are possessed of different degrees of refrangibility ; the red being least refrangible, the violet the most. It appears from Sir John Hersehell\u2019s experiments that just beyond the violet there exists a band of coloured light of still greater refrangibdit}-, which he has denominated the lavender baud. The same great philosopher has also proved that the coloured rays in the spectrum differ materially in the length and rapidity of their undulations.\nColoured rays.\tLength of luminous rays in parts of an inch.\tNumber of undulations in an inch.\tNumber of undulations in a second.\nExtreme red\t0-0000266\t37640\t458 Mill. Of Mill.\nRed\t\u25a00000256\t39180\t477\nIntermediate\t\u20220000246\t40720\t495\t\u201e\nOrange \u2022\t\u20220000240\t41610\t506\t,,\nIntermediate\t\u20220000235\t42510\t517\nYellow\t\u20220000227\t4-1000\t535\nIntermediate\t\u20220000219\t45600\t555\t\u201e\nGreen\t\u20220000211\t47460\t577\t\u201e\nIntermediate\t\u20220000203\t49320\t600\nBlue\t\u20220000196\t51110\t622 \u201e\nIntermediate\t\u20220000189\t52910\t644\nIndigo\t\u20220000185\t54070\t658\nIniermediate\t\u202200001 SI\t55240\t672\nViolet\t\u20220000174\t57490\t699\nExtreme Violet -\t\u20220000167\t59750\t727\nFrom this table it will be seen that the sensibility of the eye is confined within much narrower limits than that of the ear, the ratio of the extreme vibrations being nearly 1 *58:1, therefore less than an octave, and equal to a minor sixth.\nSir William Flerschell discovered that there are rays in the solar spectrum which give rise to the sensation of heat, independently of\nthose of light, and these calorific rays are most abundant a little beyond the red extremity of the spectrum, and gradually diminish towards the violet, beyond which they are imperceptible ; an important practical fact has recently been discovered in relation to these rays. It is well known that plants growing in stove houses often suffer from the scorching influence of the calorific rays, and when the great palm-house at Kew was about to be erected, an elaborate series of experiments was undertaken by Mr. R. Hunt, to ascertain whether it would not be possible to cut them off by means of a tinted glass. In this he was fully successful, and discovered that a glass tinted of a very pale yellow-green colour by oxide of copper completely prevented the permeation of all that class of heat rays which exists below, and in the point fixed at that of maximum calorific action ; as it is to this class of rays that the scorching influence is due, the use of the glass described has effectually protected the plants. The absence of oxide of manganese commonly employed in all sheet glass, is insisted on, it having been found that such glass will, after exposure for some time to intense sun-light, assume a pinky hue, which is highly objectionable.\nTo Dr. Wollaston we owe the discovery of the existence beyond the extreme violet of chemical rays, which are known to us solely by their effects. It is to their action that the fading of vegetable colours, and the blackening of nitrate of silver, is due. The influence of these chemical rays extends throughout the spectrum, and to it the term actinism has been applied. From the experiments of Mr. Hunt it appears that actinism exercises an important influence on the vegetable world, exciting the germination of seeds, and being essential to the formation of the colouring matter of leaves. The actinic principle is most energetic in spring, when its stimulus is required to rouse dormant vegetation from the repose of winter : as soon as this is effected, the luminous ra^s, with the advance of the sun, become more active, and the formation of woody fibre proceeds under their particular agency ; but in autumn, the actinic power having performed its part, is no longer required, the whole energy of vegetation being concentrated under the influence of the calorific rays in the ripening of fruits and perfecting of seeds. It has been long known that the calorific and luminous rays were capable of extinction by means of polarisation, but it has only been very recently ascertained by Professor Wartmann that the chemical rays are equally amenable to polarisation under similar conditions.\nThose diversified colours which render the floral world so attractive, which impart such beauty to the feathered tribes and the legions of butterflies, and in brilliant pigments reward the labours of the chemist, are not properties inherent in matter itself, but arise from the action of matter upon light, whereby certain of the coloured rays which form white light are reflected, whilst others are absorbed or transmitted. Scarlet cloth, for instance","page":1437},{"file":"p1438.txt","language":"en","ocr_en":"1138\tVISION.\nabsorbs almost all colours except red, which it reflects ; but those substances which reflect all the rays appear white ; those which absorb all are black. The brilliancy of tints is greatly increased when viewed in light of their own colour, as may be proved by throwing the red rays from a prism upon any scarlet object, or the green rays upon a green leaf. The colour of transparent substances depends upon their property of absorbing some of the colours of white light, and transmitting others. The blue tint of the atmosphere in reflected light, and its red morning and evening tinge, are to be ascribed to this cause.\nDyes and paints are substances which, when applied to bodies, so change their surfaces, that when seen in white light, they reflect only the particular colour of the dye or paint. There are several modes by which white light can be reproduced, of which a simple one is, the rapid rotation of a disk painted in stripes, with the prismatic colours in the correct proportions. In this case, the eye receives the impression at the same time, and in the same place, of a red circle, an orange, a yellow circle, and so on, and consequently a white circle, since the sensation of white is but the simultaneous sensation of all these colours.\nAs in the production of white light, it is necessary that all the simple colours should exist in their due proportions; so it is evident that by suppressing or increasing one the harmony will be destroyed, and the light will be no longer white. Thus, for instance, by suppressing red, we obtain a blneish green, which, compounded with red, would form white light. Whenever two colours, simple or compound, fulfil this condition, they are said to be complementary one to the other. They are as follows : \u2014\nColour.\t\tComplementary.\nRed -\t-\t- Blueish-green.\nOrange\t-\t- Blue.\nYellow\t_\t- Indigo.\nGreen -\t_\t- Violet-reddish.\nBlue -\t_\t- Orange-red.\nIndigo -\t-\t- Orange-yellow.\nViolet -\t_\t- Yellow-green.\nBlack -\t-\t- White.\nWhite -\t-\t- Black.\nWith respect to the production of light, bodies are divided into luminous and non-luminous ; among natural bodies some possess in themselves the property of exciting in our eyes the sensation of brightness, or light, as the sun and other heavenly bodies which shine bv their own light. lhere is also chemical light, or that produced by combustion, electric light, phosphorescent light, et cetera. Non-luminous bodies are such as become visible only when light falls upon them from some luminous source.\nBodies are also divided into transparent and opaque, in reference to their capacity for transmitting light through their substance, though this property depends, not merely on\ntheir absolute transparency, but also on the density of the medium through which the light passes. There is no perfectly opaque or perfectly transparent substance known. Diamond is nothing more than charcoal in a different state of molecular aggregation, and gold can be made pervious to light. On the other hand, the purest air or clearest water gradually extinguishes by absorption the rays transmitted through them. According to Bouguer the purest sea water loses all its transparency at a depth of 730 feet, and the reason that more stars are visible from the summit of a lofty mountain than from the level of the sea is, because the light from the more distant stars becomes so much enfeebled during its passage through the lower strata of the atmosphere, that it has not sufficient power to affect the sight.\nIf a pencil of rays diverging from a luminous point fall upon the surface of a convex lens, they will not all be equally refracted. The ray which passes through the axis of the lens will not be changed in its course, but the remainder of the rays will be more and more refracted in proportion as they recede from the optical centre of the lens. When the rays pass out from a bi-convex lens into air they are refracted from a line perpendicular to the point of emergence : the effect is to cause them all to converge towards the central ray to a point at which they meet, called the focus. The distance between the focus and the refracting surface is the focal distance or focal length, and is influenced by the refracting power of the lens, the amount of its curvature, and the distance of the luminous body.\nParallel rays entering any plano-convex or double convex lens at an equal distance from its axis, are concentrated to the same focal point, but as the peripheral rays are more refracted than the central rays, they are sooner brought to a focus ; hence the image formed at the focus of the lens is somewhat indistinct at its edges. This imperfection is due to what is termed spherical aberration, and is counteracted either by shutting out the peripheral rays, or by such a combination of lenses as will establish a just proportion between the refraction of the central and peripheral rays. Such lenses are made of crown glass, composed of flint and alkali only, and flint glass, in which oxide of lead is added to the other materials. The latter possesses a much higher dispersive power than the crown glass ; but the refraction of the rays is nearly the same in both, and when combined, achromatic lenses are obtained. This term is applied from their utility in obviating another source of confusion, chromatic aberration, which is caused by the unequal refrangibility of the prismatic rays when transmitted through an ordinary lens, whereby the images are fringed with colours, and are rendered even more indistinct than by spherical aberration. Newton supposed that an achromatic lens was an impossibility ; but in 1757 Dollond completely succeeded in overcoming the difficulty by the","page":1438},{"file":"p1439.txt","language":"en","ocr_en":"VISION.\t1439\ncombination of crown and flint glass. He supposed the mean refractive power of flint glass, as compared to crown glass, to be 158 to 153; Fraiinhofer states it to be 164 to 153. The prismatic dispersion in English flint glass is li times, but in Fraiinhofer\u2019s, it is twice as great as in crown glass.\nSuch are the chief facts concerning light, which bear reference to vision : to the consideration of the physiology of which we now proceed.\nPhenomena of Vision. \u2014 The special function with which the retina is endowed being the perception of light, a marvellous range of phenomena is open to the inquirer. It is indeed a wonderful thing to have ascertained beyond doubt, that in perceiving the tint of the scarlet geranium our eyes are affected by undulations recurring four hundred and eighty-two millions of millions of times in a second ; that before we can appreciate the tint of the yellow blossoms of the gorse or laburnum, five hundred and forty-two millions of millions of vibrations must have taken place ; and that to discriminate the colour of the violet, not less than seven hundred and seven millions of millions of movements must have been communicated to the fibrillae of our re-tin\u00e6 ! Whilst such facts almost transcend the powers of human conception, their establishment is a striking triumph of human intellect. But how great ought to be our admiration of that Omnipotence which has endowed the eye with the gift, not merely of appreciating one colour, but of distinguishing, in all their shades, the inexpressibly complicated vibrations which mark the hues of a parterre of flowers, and characterise the gorgeous plumage of the birds which give animation to a tropical forest. The sense of sight, in its ordinary acceptation, may be defined as the recognition by the mind of certain impressions made upon the retina, and communicated through the medium of the optic nerve to the encephalon ; a sound condition of each and all of these parts (which may be considered as the media of communication, so far as one sense is concerned, between the external world and the mind) is indispensable for perfect vision. Light may fall upon the retina, and the images of objects may be there depicted, but should the optic nerve be unsound, or certain portions of the brain be disorganised, no responsive image is called up before the mind ; the eye may gaze upon the noonday sun, but all is dark within.\nThe natural stimulus of the retina is the luminous rays : the appreciation of light and colour its active condition ; and its state of repose suggests the appearance of darkness : but besides light, any other excitement applied to the retina or optic nerve gives rise to the same result, \u2014 the production of luminous appearances. Pressure upon the eye-ball, the electric current, or vascular congestion, all excite this special phenomenon. Occasionally, too, irritation of the brain has the same effect ; and many are the waves and corrus-cations, the fiery clouds and flaming spectra,\nwhich haunt the amaurotic when certain morbid complications exist. The phantasms of fever, and the illusions of the dying, are to be placed in the same category with the above.\nFor visual purposes, a certain amount of stimulation of the retina is necessary ; hence it is both difficult and painful to discern objects in very faint light : but in this respect the retina is endowed with great powers of accommodation. It is well known that persons long immured in dungeons profoundly dark to ordinary eyes, have acquired the power of discerning the most minute objects. On the other hand, excessive light is injurious, for by it vision may be instantan\u00e9-^ ously extinguished, as happens by a stroke of lightning. The accommodation to various amounts of light is, however, gradual, as is proved bypassing from a dark room into sunlight, or into a brilliantly lighted apartment. In this case the pupil has been widely dilated to admit the greatest possible quantity of light into the eye. For the first second or two after arriving in the light, all is confusion; and there is even pain, from the flood of light which thus breaks in on the retina through the widely dilated pupil, and takes it, as it were, unawares. On the other hand, a person entering a moderately dark room from full sunlight, sees nothing for a time, because the strongly contracted pupil admits so little light, that no sensation is produced. After a while the pupil dilates, and vision gradually becomes complete. In order that a clear idea may be formed of the mode in which images are depicted upon the retina, and also of the causes of myopia and presbyopia, it is necessary that the mode of action of convex lenses should be described.\nFig. 884.\nLet CDbea biconvex lens, and ab an object on one side of it, but further removed than the focal point f. Every point of the object will send forth rays in all directions, but to avoid confusion, we will only consider those flowing from the extremities ab. The rays emitted from a undergo refraction, are altered in their direction, and are united at a' upon the secondary axes drawn from a through g, the centre of the lens. The rays from b are in like manner united at W\\ consequently, a'W is the image of the object ab, but inverted. Seen from the middle of the lens, the image and object appear at the same angle, for the angle b'ga' is equal to the angle bga, being angles at the vertex. The relative size of the object or the image depends upon the relative distance of","page":1439},{"file":"p1440.txt","language":"en","ocr_en":"1140\tVISION.\neach from the lens. If the object lie twice as far as the focal distance from the lens, the image will be formed on the other side at an equal distance, consequently the image and the object are equal in size. But if the object approach nearer to the glass, the image will recede, becoming larger. We thus obtain inverted and enlarged images of objects standing further from the lens than the focal distance, yet not so far as twice that distance. Thus the image a'b' is larger than the object ab. If the object be further removed from the glass than twice the focal distance, the image will be nearer ; we therefore obtain inverted diminished images of distant objects.\nDioptric \u2018phenomena.\u2014Krause has described the anterior surface of the cornea as being spherical, the posterior parabolic. We recently had an opportunity of examining a human cornea in less than an hour after theeye had been extirpated from the living subject, and satisfied ourselves that, in that case at least, the two surfaces were perfectly parallel. According to Chossat the figure of the cornea is an ellipsoid of revolution about the major axis, which axis determines the axis of the eye. The ratio of the semi axis of this ellipse to the excentrieity he determines at 1*3 ; and this being nearly the same with the index of refraction, parallel rays incident on the cornea in the direction of its axis will be made to converge, with great exactness, to a focus situated behind it, the aberration, which would have existed had the external surface been of a spherical figure, being almost completely destroyed. The form of the crystalline lens is that of a solid of revolution, having its anterior surface much less curved than its posterior : by some authorities both surfaces are described as being ellipsoids of revolution about their lesser axes ; but Krause found the posterior surface to have a parabolic curve, whose parameter was from 3f/// to 5\"'. He found also that the elliptic.il curve of the anterior surface of the lens varied as regards its long axis, in different cases from 4\"' to 5^'\"; its short axis also varying from lfw to 2\\'\". Dr. Albert de Gr\u00e4efe informs us that he has repeated these observations, and ascertained them to be correct. Valee states that he has found by a comparison of Krauss\u2019s measurements of the dimensions of the eye, that the exterior convex surfaces have exactly that geometrical form which produces foci free from deviations. He calls them optoidal surfaces, and also finds that the posterior convex surfaces are at least so far optoidal, as the pencils of light penetrating into the eye infringe upon them. The axes of the two surfaces of the lens are not exactly coincident in direction with each other, nor with that of the cornea.\nThe refractive index of the surface of the lens is, according to Brewster, 1-3767 ; of the centre 1*3990, the mean being 1*3839 : that of the vitreous humour is 1*3394; thus the refractive density of the lens being greater than that of either the aqueous or vitreous humour, it exercises an important influence\non the converging rays incident on it from the cornea. The effect of its elliptic figure is probably to correct the aberration of oblique pencils, and general aberration is still further obviated by the peculiar and varying density of its substance. By Professor James Forbes the variable density is supposed to alter the figure of the lens under pressure, and so to assist in focal adjustment.\nAs the rays refracted by the aqueous humour pass into the crystalline, and those from the crystalline into the vitreous humour, the indices of refraction of the separating surface of these humours will be, according to Brewster \u2014\nFrom aqueous humour to outer layer\nof crystalline\t-\t1'0466\nFrom ditto to crystalline, using the\nmean index\t-\t1*0353\nFrom vitreous to crystalline outer\nlayer -\t-\t-\t-\t- P0445\nFrom ditto to ditto, using the mean\nindex ----- 1*0332 Suppose, then, the eye to be directed towards an object, the rays of light proceeding from that object are thus disposed of. Those which strike the cornea very obliquely are reflected, as are those which impinge upon the sclerotic; a large proportion of the rays, however, pass through the cornea, being powerfully refracted by it, and the aqueous membrane, and less by the aqueous humour behind : proceeding onwards, many of the rays are arrested by the iris, some being absorbed, others reflected, conveying the colours and brilliancy characteristic of that membrane. The more central rays pass through the pupil and the crystalline lens. The layers of this body, increasing in density from the circumference to the centre, resemble in their effect upon the rays the atmosphere of this earth, which causes a gradual bending of the rajs flowing from the heavenly bodies ; so the crystalline lens by its form and structure gradually but powerfully increases the convergence of the raj s which penetrate it, both on their entrance and their exit. They then traverse the vitreous humour, \u2014the chief use of which appears to be to afford support to the expanded retina, \u2014and are brought in a perfectly natural eye, to foci upon the retina, forming there an exact but inverted picture of the object. If the eye of a white rabbit or any other aibino be carefully cleansed, the flame of a taper held before the cornea may be seen inverted at the back of the eye, increasing in size as the taper is brought near, diminishing if it retires, and ever moving in the direction opposite to that given to the flame.\nSuch, in general terms, are the phenomena attending the formation of images in the eye; and they are strictly in accordance with the mode of action of convex lenses, of which the rule is, that an image formed by a convex lens is inverted, and its position relatively to the position of the object and its magnitude, are to that of the object as its distance from the lens is to the distance of the object from the lens. The rays composing a pencil falling","page":1440},{"file":"p1441.txt","language":"en","ocr_en":"1441\nVISION.\nupon the cornea, are refracted by the transparent media of the eye in proportion to the difference between the density of these media, and that of the air, and in proportion to the curves presented by their several surfaces. It is of course the central ray only, or that which passes through the axis of the eye, that is not refracted ; all the other rays undergo refraction, and are approximated to the central ray. The prime rays have been termed rays of direction, because every prime or axial ray determines the direction of the other rays. As every object emits rays, from every point, in all directions, which rays then proceed in straight lines, it necessarily follows that, undergoing these refractions, there must be some point in the eye at which the axial rays of the different pencils, proceeding from the object, cross ; and this appears to be very near the centre of the eye, somewhat behind the crystalline. Sir D. Brewster places it in the geometric centre of the e_\\ e-ball, consequently a little within the crystalline lens ; and Volk-mann has described the point of intersection as being 3'\" 97 behind the cornea, O'\" 43 before the posterior surface of the crystalline, and 6'\" 23 in front of the retina. Other and very careful observers, however, place it at a very short distance behind the crystalline lens. It is called the focal centre, and the angle formed by the intersecting axial rays from two points is the visual angle. This focal centre seems, according to the researches of Ruete, to be of importance in another way. In the steady contemplation of objects, we have to bring them into the focal centre of the produced visual axis ; and in the motion by which this is accomplished, it would appear that the eye revolves accurately round a point, which point of revolution is the focal centre of the eye. In vision, the muscles of the two eyes act under the influence of the will, with a remarkable and admirable sympathy ; and it is on this harmonious consent, as it were, of opposing muscles, that vision in its most perfect form depends.\nVision under water is attended with some Curious consequences, the result of what is termed \u201c internal\u201d reflection. An eye placed under perfectly Stillwater, as for instance, the eye of a diver, will see external objects only through a circular aperture (as it were) of 96\u00b0 55/ 20// in diameter overhead. But ail objects down to the horizon will be visible in this space; those near the horizon being much distorted and contracted in dimensions, especially in height. Beyond the limits of this circle will be seen the bottom of the water, and all subaqueous objects reflected and as vividly depicted, as by direct vision ; and in addition, the circular space above mentioned will appear surrounded with a rainbow of faint but delicate colours. In the eyes of fishes, the honours being nearly of the refractive density of the medium in which they live, the action of bringing the rays to a focus on the retina is almost entirely performed by the crystalline lens, which is nearly spherical and of small radius in comparison with the whole diameter\nVOL. IV.\nof the eye; there is also a very great increase of density towards the centre, whereby spherical aberration is obviated, the corneal refraction having little influence.\nWhen speaking of light we have mentioned spherical and chromatic aberrations ; and it is necessary that they should be again alluded to in reference to the eye. Spherical aberration is beautifully counteracted by the figure and varying density of the crystalline lens ; which, increasing in refractive power towards the centre, refracts the central rays in each pencil, to the same point as its external rays; but an important agent in obviating this aberration is the iris, which is, as it were, perpetually on the watch to limit the rays entering the eye to those which produce a perfect image, cutting off others which, by their obliquity of incidence, might occasion the imperfection in question. Opticians endeavour to obtain the same effect in their instruments by the employment of an opaque screen or diaphragm ; but no device of human art can equal the ever changing pupil of the living eye.\nSir David Brewster, and some other authorities, deny that the eye is perfectly free from chromatic aberration; and it is certain that when the pupil is dilated by belladonna, and the lateral rays freely admitted, coloured fringes are perceptible, as we have ourselves experienced ; on the other hand, the forms and relative densities of the humours of the eye closely imitate the achromatic combination of lenses, for the two menisci, formed by the aqueous and vitreous humours, having the double convex crystalline lens, of greater density than either, placed between them, fulfil these conditions very happily, and can hardly fail to obviate, in a material degree, chromatic aberration. The coloured fringes we have spoken of, as being produced by the dilatation of the pupil, must not be confounded with the chromatic images, which depend on certain conditions of the retina. The former are always connected with refraction, and they attach particularly to two conditions, namely, the falling of a light close to a shadow, and the projection of the limits of either on the retina, in such a way that all sharpness of outline is lost. The transition from light to shade\u2014the blending of the light and darkness thus produced\u2014gives rise to coloured fringes. This may be shown by taking up a position, at the end of a room, before a brightly illuminated window, and holding up any small object, such as a pencil, before the eye, which must be steadily fixed upon the window-sash. Presently prismatic colours appear on either side of the bars as well as of the pencil. Goethe explained all chromatic phenomena on the sole ground of modifications in light and shade. In the light seen through dull media, according to his theory, yellow is first perceived, then in succession, red, pale blue, blue, violet, black blue, and black ; and he explains dioptrically-formed coloured margins from the subjective side, by a mutual encroachment of the light and dark, the shadow before the light being perceived as blue and\n4 z","page":1441},{"file":"p1442.txt","language":"en","ocr_en":"1442\nVISION.\nviolet, and the light before the shadow as red and yellow.\nDistinct vision. \u2014 Dugald Stewart, in his \u201c Philosophy of the Human Mind,\u201d proposes this question : Suppose the eye to be fixed in a particular position, and the picture of an object to be painted on the retina, does the mind perceive the complete figure of the object at once, or is this perception the result of the various perceptions we have of the different points in the outline ? He arrives at the conclusion that the mind does at one and the same time perceive every point in the outline of the object, for perception, like consciousness, is an involuntary operation : as no two points, however, of the outline are in the same direction, every point by itself constitutes a distinct object of attention to the mind ; but these acts of attention are performed with such rapidity, that the effect is the same as if the perception were instantaneous. When the eye is directed to any point of a landscape, it sees with perfect distinctness only that image of it which is directly in the axis of the eye ; but the extreme mobility, of the eye, together with the duration of the impressions upon the retina, enable us 'to take in every part of the view with equal distinctness. In all probability, it is only in the axis of the eye, corresponding with the yellow spot, that vision is perfect; the posterior part of the retina is certainly better adapted to receive images than the anterior, where the grey nervous layer becomes thinner and thinner towards the border. Dr. Young calculated that the range of motion in the eye-ball is 55\u00b0 in every direction, so that the head being fixed, a single eye may have perfect vision of any point within a range of 110\u00b0. He further ascertained, by fixing the eye in the most natural direction, namely, forwards, and a little downwards, and by then moving a luminous object before it in various directions, that the range of vision upwards was 60\u00b0, downwards 70\u00b0, inwards 60\u00b0, and outwards 90\u00b0, giving an entire horizontal play of 150\u00b0, and a total vertical play of 120\u00b0.\nThe small portion of retina corresponding to the extremity of the optic nerve, is insensible to visual impressions. Volkmann states that he has satisfied himself by calculation that the small insensible spot corresponds exactly with the dimensions of the central artery. Dr. Young determined that the distance of the centre of the optic nerve from the visual axis is of an inch, and that the diameter of the most insensible part of the retina is ^ of an inch. It is to be borne in mind that the fibrous lamina of the grey nervous layer of the retina is at this point evolving itself from the nerve, and is not yet invested with the vesicular or other lamin\u00e6. Mr. Bowman has well remarked that this incapacity of vision at the entrance of the optic nerve seems to be essential to the mode of junction of the retina with the nerve, since it appears to have been the chief reason why the nerve was not made to enter in the axis of the eye. If the blind spot had been situated\nin the axis, a blank space would have always existed in the centre of the field of vision, since the axis of the eyes in vision are made to correspond. But as it is, the blind spots do not correspond when the eyes are directed to the same object ; and hence the blank which one eye would present, is filled up by the opposite eye. Mariotte, was the first who described the existence of these blind spots, and they may be discovered by the following simple experiment: \u2014 Let two black dots be placed one inch apart on a sheet of white paper : if the left eye be closed, and the dots are regarded at the usual distance for distinct vision, the attention, however, being particularly directed to that on the right hand, the other dot will be found to disappear the moment the pencil of rays proceeding from it falls upon the centre of the entrance of the optic nerve.\nIt has been already stated, that, when the rays from an object meet in foci on the retina, a distinct image is formed : should the focus, however, be before or beyond the retina, it is evident that some indistinctness must be caused, for each point of the retina would then receive rays from several points of the object. It is to be borne in mind, that the nearer the object to the eye, the greater is the divergency of the incident rays ; and the greater their divergency, the more distant is their focus. When the retina corresponds, or nearly corresponds, to the points of convergence of the several pencils of light, distinct vision is obtained, the usual distance being from eight to ten inches, at which distance, reading or writing is naturally performed. If, when writing, for instance, we removed the head further, or approached it nearer, and no alteration took place in the eye, vision would become indistinct, because the focus would be altered, and would either fall short of, or be thrown beyond, the retina : should the rays, however, very nearly unite upon the retina, vision, of large objects especially, may prove sufficiently distinct, though not perfectly clear. A just distinction was, therefore, drawn by Jurin between perfect vision and distinct vision, the perfection of vision depending on the distance alone of objects, whilst their distinctness would be regulated not less by their size, than by their distance from the eye.\n' The pupil of the eye performs an important part in enabling us to see objects distinctly. When looking intently at a near object, the pupil contracts, thereby limiting the rays which pass through it to the most central, and stopping the progress of those more divergent rays which, not converging to foci on the retina, would cause circles of dissipation ; upon the same principle, vision of near objects is assisted by a pin-hole aperture. Let a person thrust a pin through a card, and make a clean hole ; then let him hold a book so close to his eyes that the type becomes confused ; if he now looks through the pin-hole, he will again see it distinctly, because the card answers the same purpose as a further","page":1442},{"file":"p1443.txt","language":"en","ocr_en":"VISION.\t1443\n'contraction of the pupil, arresting the progress of those rays which are too divergent, and limiting those entering the eye to the central rays, which, from their trifling divergence, unite correctly on the retina. The same advantage is gained by a near-sighted, and by a presbyopic eye. In the one case vision is improved by the card stopping the rays, which would converge to foci in front of the retina ; in the other, by its arresting those which tend to foci behind the retina. So that this simple experiment frequently makes a difference of several inches in the vision of myopic and presbyopic persons.\nA curious experiment devised by Father Sch einer, has reference to this point. If we make in a card two small orifices with a needle, at a less distance from each other than the diameter of the pupil, and hold these openings close to the eye, a double image of a small object held within the visual distance, \u2014 a pin\u2019s head, for instance\u2014 will be seen. From the pin\u2019s head there pass two very minute pencils of rays through the apertures into the eye. These rays converge towards a point lying behind the retina, and fall upon the retina at two different points. These are two isolated points of the circle of dispersion, which would exist upon the retina, if the other rays were not intercepted by the card. If we now withdraw the pin\u2019s head more and more, the images will approach, because the rays, falling upon the eve through the apertures, will diverge less, and will consequently be refracted towards a point lying nearer to the retina. If the object be removed from the eye to the distance of distinct vision, the two images will perfectly coincide, since all rays passing from one point, lying exactly at the distance of distinct vision, will be concentrated at one point of the retina. It may be asked, what are the conditions of adaptation necessary for an eye in looking through a fine aperture? In its normal condition, for the maintenance of which no effort is necessary, the eye is in the state necessary for seeing objects which lie at the distance of distinct vision. If a distant object be regarded through the small apertures, the rays passing through them into the eye must evidently meet at one point before the retina, as the condition of each adaptation does not change in the eye: but the two pencils diverge again behind the point of intersection, striking the retina at two different points, when, consequently, distant objects will be seen double ; therefore, we only see a small object single, through two small apertures, when it lies at the distance of distinct vision.\nThis experiment of Scheiner led Dr. Porterfield to invent an instrument called an optometer, for the determination of the focal distance of the eye; and Dr. Young subsequently greatly improved upon it, his instrument being simple in construction, and both convenient and accurate in its applica-tion.\nThe greatest distance of human vision is so variable, that no arbitrary limits can be as-\nsigned to it. Uncivilised tribes, as the North American Indians, the inhabitants of the immense Asiatic steppes, and the New Zealanders, possess powers of sight which are almost incredible. It is interesting, however, to remark, that the mean degree of capability of vision was the same among the ancient Greeks and Romans as at the present day. The Pleiades furnish the proof of this, showing that some thousand years ago, as now, stars which astronomers call of the seventh magnitude, were not visible to the naked eye in persons of ordinary powers of vision. Even among civilised nations, however, instances are occasionally met with of extraordinarily keen sight. General Drinkwater, in his *\u25a0 History of the Siege of Gibraltar,\u201d mentions that there were two boys in the garrison possessed of such uncommon quickness of sight, that they could see the shots fired by the enemy almost immediately after they had quitted the guns, and were constantly employed to look out and give warning to the soldiers of the approach of these missiles.\nFrom the experiments of Harris, it seems that a simple object, as a black square on a white ground, or a white square on a black ground, can be seen under a less angle than the equal parts of a compound object, as the squares of a chequered figure, and that their least, or minimum visible angle cannot be less than 40\" : others, however, say 30\". If it is 40\", the size of the image on the retina will be -s\u00f6V\u00f6 inch. At a medium, Harris thinks it not less than 2'. He remarks that the difficulty of keeping the eye perfectly steady, may be one cause why a single object can be discerned under a less angle than the parts of a complex one ; and that it is natural to suppose that the fewer objects we contemplate, and the more they differ in colour, the easier we can distinguish their several impressions on the retina. The result of repeated and very careful experiments by Hueck, tends to show' that white objects on a black ground are seen at a greater distance than black objects on a white ground *, and this is fully corroborated by an instance mentioned by Humboldt. This distinguished traveller was with Bonpland, at\n* The following facts, deduced from extensive and very careful experiments, conducted by Lieut.-Colonel Hamilton Smith, are of great practical importance. The object was to ascertain the liability of different colours to be hit as marks, under precisely similar circumstances, as to men engaged, size of target, weather, &c. The result showed the proportion to be as follows. \u2014\nRed, 12. Rifle-green, 7. Austrian blueish-grey, 5.\nColonel Derinzy, who was actively engaged in the Peninsular War, has given much attention to the effect of different coloured uniforms on the chances of being hit. The day before the battle of Yittoria, his Portuguese rifle company, dressed in earthy-brown, and a company of British Fusil eers, of equal strength, dressed in red, had to dislodge the French from a bridge. They were equally exposed during the whole of the skirmish, and after it was over, Colonel Derinzy compared notes with his Fusileer comrade, and found that the relative losses were precisely one to two ! This fact (for which we are indebted to Captain Nelson, k.e.) strikingly\n4 z 2","page":1443},{"file":"p1444.txt","language":"en","ocr_en":"HU\nVISION.\nChillo, near Quito, in South America, from whence the long extended ridge of the volcano of Pichincha is visible. Bonpland had proceeded on an expedition to the volcano, and Humboldt, with others, was somewhat anxiously looking out for him. The Indians of the party recognised the traveller as a white point moving along the face of a black basaltic precipice, before he was discovered by Humboldt and others, who were looking out for him with telescopes (a proof, by the wa}', of their excellent vision) ; but in a short time the Europeans also were able to distinguish the white moving figure with the naked eye. The weather was clear, and the distance 1P8 geographical miles. A small object in motion, however, is more easily discerned than if at rest : by the gradual motion of the image over the retina, the impression upon each part continuing for some time, the effect is the same as if a linear image were formed.\nDuration of impressions. \u2014 A beautiful provision to insure uninterrupted vision, is afforded by the duration of impressions upon the retina, whereby we never lose sight of an object we are viewing, during the necessary winking of the eyelids. M. D\u2019Arcy found that the light of a live coal, moving in a circle, at the distance of 165 feet, maintained its impression upon the retina somewhat more than the seventh part of a^second. From the observations of Plateau, it seems that the interval of time, during which the impression retains the same intensity, is more considerable in proportion as the light is moderated ; the mean duration of the impression excited by all the colours from the instant of their maximum intensity till their entire disappearance, being one-third of a second in a dark room, and one-sixth of a second in a light room. If two or more impressions succeed each other at such short intervals that the first has not faded away before the next commences, they run one into another, the eye seeming to receive but a single impression ; as, for example, the appearance of a circle of fire from a revolving burning stick \u2014 when it is in reality the combination of many individual impressions succeeding each other with rapidity : upon this depends many of the most beautiful examples of the pyrotechnic art ; from the same cause a flash of lightning appears as a continuous line of light, because the light emitted at any point of the line remains upon the retina until the cause of the light passes over the succeeding points. In order that an object may become visible, it is necessary that the retina should be exposed to its influence for an appreciable time, a fact first pointed out by Lord Bacon, who observes, that notwithstanding the rapidity of the act of vision, a certain time is required for its exercise, which is proved by certain objects, as, for instance, a musket-ball, being invisible on\ncorroborates Colonel Smith\u2019s results : hence it ap \u2022 pears that the liability of brown is '^-'-6, and\nthat red is by far the most fatal colour, green next, then brown, and Austrian grey the least.\naccount of the velocity of their motion ; for the flight of the ball, he remarks, is too swift to allow an impression of its figure to be conveyed to the sight. This subject has been recently investigated with much success by Mr. Wdliam Swan*, who arrives at the following conclusions.\nWhen the eye receives a succession of flashes of equal duration from a light of constant intensity, which succeed each other so rapidly as to produce a uniform impression, the intensity of this aggregate impression will also be constant, provided the number of flashes in a given time varies inversely with the duration of each. The brightness of the impression produced by flashes of light of a given intensity, which succeed each other so rapidly as to produce a uniform impression on the eye, is proportional to the number of flashes in a given time.\nWhen light of a given intensity acts on the eye for a short space of time, the brightness of the luminous impression on the retina is exactly proportional to the time during which the light continues to act. This law has been proved to be true for impressions lasting from Tsljj to \u00e4V \u00b0f a second.\nThe intensity of the impression produced by light, which acts on the eye for of a second, is almost exactly T^th\tapparent\nbrightness of the light when seen by uninterrupted vision ; and the time required for light to produce its full effect on the eye seems to be about -fa of a second. Lights of different intensities produce their complete impressions on the eye in equal times, so that the light of the sun requires the same time as common artificial light to produce its impression on the eye. The brightness of an impression on the eye increases with a rapidity exactly proportional to that of the light by which it is produced.\nRays of different refrangibility act on the eye with equal rapidity. The apparent brightness of the spark produced by electricity of high tension is only about -nrsWs \u00b0f \"hat its apparent brightness would become if its duration were prolonged to of a second ; and the brightness of electric light increases with the tension of the electricity.\nThe wonderful rapidity of the electric light is shown by the following experiments: \u2014Viewed by the illumination of an electric spark, the spokes of a wheel in the most rapid rotation appear stationary, vibrating cords seem to be in a state of repose, and a succession of drops, which generally appear to the eye as a connected stream, is seen to be but a succession of drops, because the impression of each image lasts for so short a time that the position of the moving bodies is not altered. The light of electricity of high tension has a less duration than the millionth part of a second.\nWhen on the subject of light, we have alluded to the reproduction of the impression of white light by the rapid revolution of a disk\n* Transactions of the Royal Society of Edinburgh, vol. xvi. p. 581.","page":1444},{"file":"p1445.txt","language":"en","ocr_en":"VISION.\t1445\npainted with the prismatic colours ; and Plateau describes an experiment which leads to a singular result. He takes two disks of exactly the same size, made of thick white paper, and divides one into eight equal sectors, of which two and two, corresponding and opposite ones, are coloured red, white, blue, and black. The second disk is coloured entirely black, two sections lying opposite to one another, and rather shorter and narrower than those of the first disk, being cut out. Both disks are then attached to rollers which are as much equal to one another as possible. They are placed vertically behind one another, so that the axes of rotation coincide, and the rollers are set in motion by cords which pass over two wheels, as nearly as possible equal to one another. The posterior coloured disk, which is rendered transparent by varnislq is well lighted from behind by a lamp. On rotation of the disks the whole field at first appears black, but, by gradual transitions, it passes into red, then white, and lastly into blue.\nThe stimulus of vivid light produces an effect upon the retina which is stronger and lasts longer, in proportion to the intensity of the primitive effect. The after-images of light objects will be light, and those of dark objects dark, if the eye be withdrawn from all subsequent action of light. If, for instance, we look long through a window towards the clear sky, and, turning suddenly away, close the eye, we shall see the light intervening spaces bounded by the dark window frames ; but if, on the contrary, the eye be turned towards a white wall, the after-image of the frame will appear light, and the intervening spaces dark. The reason is, that if the eye, already dazzled, be turned towards the white surface, the parts of the retina previously affected by the bright light will be less sensitive to the white light of the wall, than those parts on which the image of the dark window frames has fallen, and which has therefore not been unduly stimulated. If the bright sun, or the intense light resulting from the combustion of lime in oxygen, be gazed upon, the spectrum continues for a long period, and if the eye be closed, it passes through a series of colours until it disappears. The white is followed by yellow, orange, red, green, violet, and finally black, one after the other in regular succession. Sir Isaac Newton experimented upon this subject, and ran a great risk of blinding himself thereby, as is described by him in a letter to John Locke, dated June 30th, 1691. After detailing the various steps of his experiment o. gazing on the sun, and observing the subsequent phantasm, he says, \u2014 \u201c At length by repeating this, without looking any more on the sun, I made such an impression on my eye, that if I looked upon the clouds, or book, or any bright object, I saw before it a round bright spot like the sun ; and, which is still stranger, though I looked upon the sun with mv right eye only, and not with my left, yet my fancy began to make an impression upon my left eye as well as upon my right. For if I shut my right eye and looked upon a book\nor a cloud with my left eye, I could see the spectrum of the same almost as plain as without my right eye if I did but intend my fancy a little while upon it : for at first if I shut my right eye, and looked with my left, the spectrum of the sun did not appear till I intended my fancy upon it ; but by repeating this it appeared every time more easily. And now in a few hours\u2019 time 1 had brought my eyes to such a pass, that I could look on no bright object with either eye, but I saw the sun before me, so that I durst neither write nor read : but to recover the use of my eyes, shut myself up in my chamber made dark for three days together, and used all means to direct my imagination from the sun ; for if I thought upon him, I presently saw his picture, though I was in the dark : but by keeping in the dark, and employing my mind upon other things, I began in three or four days to have some use of\u00b0my eyes again, and by forbearing to look upon bright objects, recovered them pretty well, though not so well but that, for some months after, the spectrum of the sun began to return as often as I began to meditate on the phenomena, even though I lav in bed at midnight with my curtains drawn.\u201d\nDiviensions of'Objects.\u2014With the representation of external things by means of the organ of vision, the mind combines its knowledge of their size and distance. We infer the real magnitude of an object from its apparent magnitude, or from the angle under which its rays intersect each other in the eye ; our knowledge of its actual distance from us is merely a deduction of our judgment arrived at through the sensations excited in the eye according to the different positions of objects, and such sensations are regulated by the angle of vision. For instance, we infer the increased distance of an object of known size, as a man, from the decrease of the visual angle. The angle of parallax, or that angle which the axis of the eyes when directed towards an object forms with it at the point of contact, is also to be taken into account, for it becomes greater in proportion to the nearness of the object. We are further aided by the position of the object relatively to other known objects, but here, in forming our conception of true dimensions, we are largely assisted by the lessons of experience. The infant will grasp at the moon ; and it is by degrees that it acquires such experience and judgment that the original perceptions of sight become signs of the tangible qualities of external objects, and the distances at which they are placed. In determining the relative distances of objects one to another, we are principally guided by the angle of vision ; yet what an exercise of judgment is implied, founded on a comparison of a variety of different circumstances, and involving a complex mental operation, when a magnificent prospect is displayed to our view, and by an inslanta-^ neous act of the mind we become aware of the various distances at which all the component parts are placed, the size of each individual part, and the relation held by each to the others. Here however, clearness of at-\n4 z 3","page":1445},{"file":"p1446.txt","language":"en","ocr_en":"1446\nVISION.\nmosphere and a sufficient amount of light are of importance, for every one must be aware how deceptive is the estimate of the size of an object when seen through a fog, or looming large in the gloom of the evening.\nSome persons are gifted, as it were, intuitively with the power of judging correctly of the true dimensions of objects. Napoleon possessed this in an eminent degree. He could tell at a glance the number of men composing a distant mass of troops, and the space of ground they would cover when deployed. In doing this a mental computation must have taken place unconsciously, rapid as thought, and based on a combination of great powers of calculation, long experience, and profound knowledge of the subject.\nFor the production of a distinct image on the retina it is necessary that it be of a certain magnitude, which will depend on the susceptibility of the eye. We may here observe that the apparent magnitude of an object must not be confounded with its apparent superficial magnitude, the term being applied to its linear magnitude. The apparent superficial magnitude varies in proportion to the squares of the apparent magnitude. The image of an object moderately illuminated must be 0 001 of an inch long, or the extreme rays of light must form an angle of half a minute in the eye at a minimum ; whence it follows that an object of mean illuminating power will be visible if its distance is not greater than 68,000 or 69,000 times its greatest length. Strongly luminous bodies, as the fixed stars, are visible at infinitely small visual angles. They excite in the eye merely a sensation of light, without creating any impression as to their apparent magnitude. The disk of the moon subtends a visual angle of half a degree, the diameter of its picture on the retina will be of an inch, and the entire superficial magnitude of the image the ^iooth \u00b0f a square inch ; yet forms of light and shade are perceptible whose linear dimensions occupy upon the retina a space whose diameter does not exceed the Tpp\u00e8'pgg'of a square inch. The eye in a healthy condition is capable of reading print in the light of the full moon, and that of the noonday sun, their intensities being to each other as 1 to 300,000. Plateau asserts that white may be distinctly seen in the light of the sun at an angle of 12\", yellow at an angle of 13\", red at 23\", and blue at 26\", but that in ordinary daylight these angles must be half as large again.\nIn estimating the motions of objects, we are guided by the movement of their images on the retina; and unless a body moves in such a manner that the line of vision shall describe at least one degree in each minute of time, its motion will not be perceptible ; for which reason we are not conscious of the movements of the heavenly bodies. The more nearly at right angles to the line of vision the direction of the motion is, the greater will be the apparent motion produced by any real movement of an object.\nErect Vision. \u2014 A variety of explanations have been offered to account for objects\nnot being seen reversed, according to the position in which they are depicted on the retina ; but it would appear that by many a sufficient distinction has not been drawn between seeing the image and seeing by means of it. A little reflection shows that the actual perception of the object takes place in the sensorium, and that the image on the retina is only a necessary step in the process. In truth, we have no notion of upright or inverted, except that which is founded on experience. A man is upright whose head is upwards, and his feet downwards. Whatever be our standard of up or down, the sensible representation of up will always be an image moving on the retina towards the lower side, and the sensible representation of down will be a motion towards the upper side. The head of the man\u2019s image is towards the image^ of the sky ; its feet are towards the image of the ground ; and consequently it cannot appear otherwise than upright. So, as all objects are inverted on our retinae, they do not change their relation one with another, and our only knowledge of position is from relative relation, therefore we may truly say that we do not see the image on the retina, but by means of it. For every image on the retina, we substitute an object, and seek in a definite direction for the object corresponding to a definite image on the retina. In this we are assisted by other perceptions of sense, there existing the greatest harmony between such percept tions in respect to locality.\nDr. Alison, in an able paper*, advances the opinion, that the harmony between the intimations acquired by sight and by touch, as to the relative position of objects or their parts, notwithstanding that the impressions made by them on the external organs of sight and of touch are arranged inversely in regard to one another, arises from the course of the optic nerves and tractus optici, whereby impressions on the upper part of the retina are in fact impressions of the lower part of the optic lobes \u2014 that is to say, of the sensorium \u2014 and impressions on the outer part ol the retina are, in like manner, on the inner part of the sensorium. This theory was first suggested by Mr. Dick, a veterinary surgeon ; but though ingenious, can hardly be considered satisfactory, as it implies the necessity for conditions which cannot always be fulfilled : and truly the question is of a nature not to be decided merely by anatomical inquiry.\nKepler\u2019s explanation of objects appearing erect to us is, that the mind, perceiving the impulse of a ray on the lower part of the retina, conceives this ray to be directed from a higher part of the object, and vice versa. Porterfield argues that the mind never sees any picture painted on the retina, and consequently never judges of the object from what it observes in the picture ; and that in seeing any\n* On Single and Correct Vision, by means of Double and Inverted Images on the Retinae, Transactions of the Royal Society of Edinburgh, vol. xiii.. p. 472.","page":1446},{"file":"p1447.txt","language":"en","ocr_en":"1447\nVISION.\nobject the mind, by virtue of a connate immutable law, traces back its own sensation from the sensorium to the retina, and from thence outwards, along right lines drawn perpendicularly from every point of the retina on which any impression is made by the rays forming the picture, towards the object itself, by which means the mind always sees every point of the object, not in the sensorium or retina, but without the eye, in these perpendicular lines. But these lines nearly coincide with the axes of the several pencils of rays that flow to the eye from the several points of the object ; and since the mind has also a power of judging rightly of the distance of objects, it follows that every point of the object must appear and be seen in the place wheie it is, and consequently the object must appear in its true erect position, notwithstanding its picture on the retina is inverted. This theory of lines of visible direction Reid regards as a law of nature, of which our seeing objects erect, from inverted images, is a necessary consequence. Sir David Brewster too believes that erect vision results from the lines of visible direction being in all cases perpendicular to the impressed part of the retina ; but Muller offers the following objections: \u2014 \u201c The hypothesis that erect vision is the result of our perceiving, not the image on the retina, but the direction of the rays of light which produce it, involves an impossibility, since each point of the image is not formed by rays having one determinate direction, but by an entire cone of rays. And, moreover, vision can consist only in the perception of the state of the retina itself, and not of any thing lying in front of it in the external world. The hypothesis also that the retina has an outward action, and that objects are seen in the direction of decussating lines, that is to say, in the direction of the perpendicular of each point of the concavity of the retina, is a perfectly arbitrary assumption since there is no apparent reason why' one direction should have the preference rather than another, and each ultimate sensitive division of the retina, if it had the power of action beyond itself, would act in as many directions, as radii might be drawn from it towards the exterior world.\u201d* Notwithstanding these objections, the law of visible direction affords the most satisfactory explanation of the phenonmena of erect vision ; all, however, we know positively is, that in the ordinary exercise of vision, the mind infers the positions of objects from an impression made upon the retina, and that it as certainly draws the right conclusion therefrom.\nThis, however, is not more wonderful than that the undulations of the luminous particles should excite the sensation of light in the retina, or that vibrations acting on the auditory nerve should give rise to sound. We may heap conjecture on conjecture as to the final cause of these phenomena, but we must stop at the limits to the boundaries of human knowledge. The profound resources of the\nDivine Intelligence excite our wonder and exalt our thoughts, but there are a thousand things abstractedly possible which set at nought our comprehension.\nIt is curious that such an acute mind as that of the late eminent metaphysician, Dr. Brown, should have been so satisfied that the perception of the number and position of visible objects is acquired only by association or custom, that he dismissed the subject thus curtly:\u2014\u201cIn the single vision of the erect object from a double image of the object inverted, there is nothing at all mysterious to any one who has learnt to consider how much of the visual perception is referable to association. If the light reflected from a single object touched by us had produced, not two merely, but two thousand, separate images in our eyes, erect or inverted, or in any intermediate degree of inclination, the visual feeling thus excited would still have accompanied the touch of a single object ; and if only it had accompanied it uniformly, the single object would have been suggested by it, precisely in the same manner as it is now suggested by the particular visual feeling that now attends the double inverted image.\u201d * It has been justly remarked by Dr. Alison, that if it were only by experience and association with the perceptions of touch that we learned that any object placed before the eyes, and seen by two images, is nevertheless single, we might reasonably conclude that we should never see an object double which we know by touch to be single ; whereas we all know, that if by pressure on the ball of one eye, or by any other means we direct the axes of the two eyes to different points in an object, we immediately see it double, and cannot by any means avoid seeing it double so long as that condition of the eyes continues, notwithstanding the full conviction, derived from touch, of its being single. This tangible theory (if the expression may be used) has found little favour, but having met with the support of so able a man as Dr. Brown, it could not be passed over in silence.\nSingle Vision. \u2014 When both eyes, acting simultaneously, are directed to an object, a single image only is seen. A variety of opinions have existed with reference to this interesting point, some of them sufficiently singular. Gassendi, Du Tour, Porta, and Gall, for instance, asserted that we do not make use of more than one of our eyes at a time, the other being relaxed, and inattentive to objects. Dr. Briggs supposed that single vision was owing to the equal tension of the corresponding parts of the optic nerves, whereby they vibrated in a synchronous manner ; and Dr. Reid was of opinion that the correspondence of the two eyes, on which single vision depends, arose from some natural constitution of the eye and mind. Porterfield says that the true cause why objects do not appear double, depends on the* faculty we have of seeing things in the place where they are, every point of an object\n* Lecture 29.\nElements of Physiology, by Baly, p. 1171.\n4 z 4<","page":1447},{"file":"p1448.txt","language":"en","ocr_en":"1448\nVISION.\nbeing seen nearly in a straight line drawn perpendicularly to the retina from that point of it where its image falls and this law of visible direction may be regarded as exercising an important influence on the production of single vision.\nIn reference to this phenomenon, it is necessary to advert to the remarkable structure of the commissure of the optic nerve. The chiasma results from the junction of the optic tracts, in front of and inferior to the tuber cinereum. The fibres which constitute the inner margin of each tract, B, are continued\nFig. 885.\nacross from one side of the brain to the other, forming no connection with the optic nerves, and existing where those nerves do not exist, as in the mole. These fibres may be considered as commissural between the thalami of opposite sides. The remaining fibres of the tracts go to form the optic nerves, the central passing across to the nerve of the opposite side, and the outermost, c c, passing to the optic nerve of the same side. Besides these, the two retinae are brought into direct connection by the fibres, a, which form the anterior border of the chiasma. From this arrangement it appears that corresponding parts of the two retinae are brought into relation one to the other, in the same manner as corresponding parts of the cerebral convolutions are linked together by the varions commissures : the right side of each retina appears also to be continuous with the right optic tract, and the left side of each with the left ;thus each side of the central apparatus is brought into communication with its' own side of both retinal images, which may be supposed to favour their conception as one.\nThe learned Arabian Alhazen supposed that when corresponding points of the two retinae are affected, the mind perceives one image ; this opinion has found favour ; but Dr. Todd and Mr. Bowman, and also Dr. Alison have especially pointed out the importance of the decussation of the commissural fibres. Dr. Alison arrives at the conclusions : first, that certainly in some, and probably in all animals, the structure of the optic nerve brings the impressions which form inverted images on the retina into the same order on the sensorium as those which might result from the touch of the same objects ; secondly, that in those animals which can direct both eyes to one point, the partial decussation of the optic nerves, generally if not universally present, enables the images produced by an object on the corresponding parts of the retin\u00e6 of the two eyes to co-operate in pro-\nducing one impression on the sensorium, and one sensation in the mind ; and lastly, that the decussation which takes place in the corpora pyramidalia affords correct information as to objects of sight from impressions made on them simultaneously in both optic lobes, \u2014 that is to say, on both sides of the sensorium,\u2014 notwithstanding that the impression on each side of the sensorium comes from the opposite side of the object in view. Thus it will be seen that Dr. Alison refers the connection of sight with touch to the decussation of the corpora pyramidalia. We may fairly conclude that there must be some structural provision in the organisation of the cerebral portion of the visual apparatus, which favours the perception of a single image from a double impression, and keeps in perfect harmony the important senses in question : how far the corpora pyramidalia may be concerned, is matter of speculation. The precise action of the mind, by which the single image only is appreciated, is of course unknown to us, but an additional argument in favour of the part performed by the chiasma is afforded by the occurrence of cases where only half an object or word is seen when both eyes are directed to it. Thus,as has been humorously illustrated by Dr. Hull, the word patriot becomes riot ; and of matrimony, only mony is seen. Such phenomena are (as remarked by Dr. Todd and Mr. Bowman) readily explained by supposing the anatomical arrangement of the sides of the retina, with regard to the optic tracts, to be such as has been described, since any derangement of one optic tract would then affect the same part of both optic images.\nFor the production of single vision, it is necessary that the muscles which move both eyes should act in perfect concert. The effect of this is, that the axes of the eyes converge towards the object to which they are adjusted, and the image falls on corre-\nFig. 886.\nsponding parts of the two retinae. Let A b be the two eyes, and c any object before them. Then ac, bc are their axes, which meet in c. An image is consequently produced in each eye which will correspond with the perspective projection of the object from the points a and b. If the two images are un-symmetrically placed, so that the axes meet either before or behind the object, a double sensation is excited, as happens in strabismus, and the double vision of intoxication. The upper sides of both retin\u00e6 correspond, as do the lower; and the outer side of each corresponds with the inner side of the other ; but the objects and corresponding points of the retin\u00e6 should","page":1448},{"file":"p1449.txt","language":"en","ocr_en":"VISION.\n1449\nlie in a certain circle, designated the horopter; a circle which passes at once through the point of coincidence, l, of the visual axes, l a, l b, and the points of decussation, c o', of these axes with the lines of direction.\nFig. 887.\nLet c c' be the centres of the eyes ab,/ the point regarded, / c & the horopter, a and b the points of the retina on which the axes of the eyes terminate ; and let m be a second point in the horopter. The point / appears upon the axial points a and b, the point m at o and p ; a line betwixt / m will form the chord of the arc of the horopter lying between / and vi ; and as all triangles drawn upon the arc of a circle have equal peripheral angles, so is the angle l c m equal to the angle / c'in. Both are farther equal to the opposite angles oca, p c' b. Moreover o c is equal to p c, and a c to b c', as radii proceeding from the centres c and c' of the retinal circles, which in each eye have an equal circumference. Consequently o is just as far from the axial point a, as p is from the axial point b ; and so identical or corresponding points of the retina are affected by the rays proceeding from both / and in. It is, however, to be borne in mind, that though impressions made on non-corresponding points of the middle portions of the two retinae are perceived as two, impressions made on non-corresponding points of the circumferential parts are not so perceived, the distance between such points being within certain limits.\nWhen an object is viewed at so great a distance that the optic axes of both eyes are sensibly parallel when directed towards it, the perspective projections of it seen by each eye separately are similar, and the appearance to the two eyes iy precisely the same as when the object is seen by one eye only. But this similarity no longer exists when the object is placed so near the eyes that to view it the optic axes must converge : under these conditions a different perspective projection of it is seen by each eye ; and these perspectives\nare more dissimilar as the convergence of the optic axes become sgreater. Fig. 888. represents the two perspective projections of a cube, b is that seen by the right eye, and a that presented to the left eye, the figure being supposed to be placed about seven inches immediately before the spectator and viewed with each eye alternately, the other being closed, and the head kept perfectly steady.\nFig. 888.\ny\t\t\t\t/\t\t\\\t\\\tN\n\tA\t\t\tB\t\n\t\t/ \\\t\t\t\\\nMr. Wheatstone has shown that the single sensation excited by these two images is that of a third image different from them both, but excitable only by both of them at once, and attended with the notion of solidity or projection in relief. This he has illustrated by a most ingenious instrument called the stereoscope. Accurate representations are drawn of the appearance presented by an object of three dimensions, when viewed by each eye at a short distance. These drawings are then placed symmetrically in the right and left compartments of a small box, so as to be reflected by sloping mirrors to the eyes of the observer, who must place them as near as possible to these mirrors ; then, by moving sliding panels to or from him, he will find a position, and one only, in which the binocular image will be seen single, of its proper magnitude, and without fatigue to the eye, because in this position only the ordinary relation between the magnitude of the pictures on the retina, the inclination of the optic axes, and the adaptation of the eye to distinct vision at different distances, are preserved. It being thus shown that there is an essential difference in the appearance of objects when seen with both eyes, and when only one eye is employed; and that the most vivid belief of the solidity of an object of three dimensions arises from two different perspective projections being simultaneously presented to the mind, the question arises, how is it that persons who see with only one eye form correct notions of solid objects, and never mistake them for pictures ? and how happens it that a person having the perfect use of both eyes perceives no difference in objects around him when he shuts one of them? To explain these apparent difficulties, says Mr. Wheatstone, it must be kept in mind that, although the simultaneous vision of two dissimilar pictures suggests the relief of objects in the most vivid manner, yet there are other signs which suggest the same ideas to the mind, and are less liable to lead the judgment astray in proportion to the extent of our previous experience. The vividness of relief arising from the projection of two dissimilar pictures, one","page":1449},{"file":"p1450.txt","language":"en","ocr_en":"H50\nVISION.\non each retina, becomes less and less as the object is seen at a greater distance from the eyes, and entirely ceases when it is so distant that the optic axes are parallel while regarding it. We see, with both eyes, all objects beyond this distance precisely as we see near objects with a single eye ; for the pictures on the two retinae are then exactly similar, and the mind appreciates no difference, whether two identical pictures fall on corresponding parts of the two retinae, or whether one eye is impressed with only one of these pictures. A person deprived of the sight of one eye sees therefore all external objects, near and remote, as a person with both eyes sees remote objects only: but that vivid effect, arising from the binocular vision of near objects, is not perceived by the former, who, to supply the deficiency, resorts to other means of acquiring more accurate information ; and of these the motion of the head is the principal.\nMr. Wheatstone has also shown that, if similar images, differing only in magnitude, are presented to analogous parts of the retinae, the resultant idea is that of an image apparently intermediate in size between them*\nFoucault and I. R\u00e9gnault have employed the stereoscope to determine whether complementary retinal images produce the impression of white on corresponding points of both eyes. Two complementary rays, obtained by chromatic polarisation, were thrown in a horizontal direction on the mirrors of a stereoscope, and reflected from them on the screens attached at the sides, so that two small disks of paper were coloured by them. At first one or other complementary colour was alternately seen : after a time, however, the two impressions united.to form white; and when the eyes had once become accustomed to this, a whole series of complementary colours could be introduced successively, and nothing but white was seen during the entire experiment.\nFrom the following interesting experiments by Sir David Brewster, it appears that we give solidity and relief to plane figures by a suitable application of colour to parts that are placed at different distances from the eye. If we look with both eyes through a lens about two and a half inches in diameter, at an object having colours of different refrangibilities, as a red rose among green leaves, the two colours will appear at different distances from the eye of the observer. In this experiment we are looking through the margin of two semi-lenses, or virtual prisms, by which the more refrangible raj's are more refracted than the less refrangible rays. The doubly coloured object is thus divided into two, as it were, and the distance between the two blue portions is as much greater than the distance between the two red portions (red and blue being supposed to be the colours) as twice\nDlllUUUiai v joiv/u, -......0~\n:iety of Edinburgh, vol. xv.\nthe deviation produced by the virtual prism, if we use a large lens or two semi-lenses, or by the real prisms if we use prisms. The images of different colours being thus separated, the eyes unite them, as in the stereoscope, and the red image takes its place nearer the observer than the blue, in the same manner as the two nearest portions of the dissimilar stereoscopic figures stand up in relief at a distance from their more remote portions. The reverse of this will take place, if a concave lens be used, or if the refracting angles of the two prisms be turned inwards. The modified stereoscope has very recently been applied to photographic purposes with the happiest results.\nAdaptation to distance. \u2014 On no subject connected with the physiology of the eye has there been a greater diversity of opinion than on the mode in which adjustment to distance is performed. That such adjustment is necessary, is proved by the simple experiment of looking between the fingers held about eight inches from the eye, at a distant object. When the distant object is seen distinctly, the fingers will be seen indistinctly; and if we look at the fingers so as to see them quite distinctly, the distant object will be indistinct. Our space will not admit of our doing more than glancing rapidly at the theories which have been advanced, and eagerly supported, to account fur this alteration in the focus of the eye. By Bayle, Rohault, Home, Olbers, and Schroeder Vanderkolk, alteration in the form of the eye by means of the external muscles was supposed to be the medium of adjustment. The movements of the iris have had their supporters, of whom the principal were Mile and Pouillet. Ramsden and Sir Everard Home regarded a change in the convexity of the cornea as the medium of adjustment. By John Hunter and Dr. Young (who devoted much time to the inquiry), elongation and shortening of the axis of the lens, through a contractile power inherent in the lens itself, were supposed to be the cause ; and lastly, it was referred by many authorities, including Kepler, Scheiner, Camper, and Porterfield, to the movement of the lens by means of the ciliary processes. Porterfield was probably the first who hit upon the true explanation, by referring the adjustment to the action of the ciliary body upon the crystalline, and by distinctly asserting the muscularity of the ciliary body. In reply to the arguments of De la Hire (who maintained that at whatever distance objects were placed, the eyes never altered their focus), Porterfield acutely observes : \u201c This author maintains that it is impossible the crystalline can change its situation, because the ciliary ligament is not muscular, and consequently has no power of contraction : and of this opinion are likewise a great many anatomists, and in particular Hovius : but it appears that all of them have been led into this mistake by an unjust notion they have entertained about the colour of muscles. Every body knows that our muscles are generally of a red colour; but","page":1450},{"file":"p1451.txt","language":"en","ocr_en":"VISION.\t1451\nit does not from tlience follow that what is not red is not musculous. The muscular fibres of the guts and stomach have scarce anything of redness in their colour ; and it is also certain that the pupil does contract and dilate itself according as objects are more or less luminous, and yet none of the fibres which perform that action are in the least red. Whence it follows that the fibres of the ligamentum ciliare are not to be deprived of a power of contraction because of a colour different from what generally obtains in other muscles ; nor are we to be surprised that so many accurate anatomists, after a careful examination of this process, have not scrupled to affirm it to be truly muscular.\u201d\nMons. Pouillet has advanced the hypothesis that, by the peculiar conformation of the lens, near objects are seen through the medium of the rays passing through its centre, and distant objects by means of the circumferential rays, lie describes the crystalline lens as made up of strata, differing in curvature and density, so that its section exhibits a series of concen-trical ellipses having varying excentricities, the internal strata being more curved and more dense than the external ; whence the rays which pass from the latter converge to a more distant point than those from the former. According to this theory, the crystalline lens has many different foci, and the effect should be* that when a pencil of rays falls upon it, those rays which are near the axis of the pencil, and therefore near the centre of the lens, are brought to a shorter focus than those which are near the border ; whence near objects would, says M. Pouillet, be seen by means of the central rays, and distant objects by means of those rays which fall near the borders of the crystalline lens.\nIt has been observed that De la Hire denied that there is an alteration in the focus, whether we look at a near or distant object. He regarded the whole adjustment as a simple enlargement and diminution of the pupil. At first sight this may appear absurd, but there are facts which give some colour to his theory. That a change in the size of the pupil has a considerable influence upon the distinctness of objects at different distances, is known, and if the eye be turned to a near object, as a book, after it has been gazing at a distant ship, the illumination of both being equal, the pupil is observed to contract. Dr. Mackenzie says, it is an error not unfre-quently adopted, that if the rays which pass into the eye from a distant object, and those from a near object, have the same divergence, a circumstance which may depend on a mere change in the size of the pupil, they will be collected on the same point of the retina Avithout any change in the refractive media of the eye. That this cannot be the case, is evident from the fact that the rays from a distant object, and those from a near object, although they may have the same divergence, fall on the cornea at different angles of incidence, and must necessarily meet the axis of the'eye at different points after, refraction.\nNow the whole effect of the alteration in the size of the pupil is, as explained elsewhere, to increase the distinctness of objects by cutting off those rays which would cause circles of dispersion on the retina. On the one hand, an enlargement of the pupil gives distinctness to distant objects, by allowing a greater quantity of light to enter the eye, and on the other, its contraction assists in rendering near objects distinct by cutting off' the lateral rays which are not duly refracted, and would cause confusion of the image on the retina. If, however, a proof were required to show that something more than a mere alteration in the form of the pupil is necessary to the perfection of vision at all distances, it would be afforded by the change termed presbyopia. The eye, in what may be called its state of perfect indolent vision, is adapted only to see distant objects, the adjustment to the near focus requiring an effort : the power to make the effort in question is partially or entirely lost by the presbyopic eye, yet the pupil may act as vigorously as ever. Though it is not unusual to find a degree of sluggishness in the actions of the pupil in elderly persons, yet we have repeatedly seen instances in which the iris acted with great vigour, and where a book was obliged to be held at arm\u2019s length for the type to be distinctly seen.\nWagner and Dr. Clay Wallace of New York follow Porterfield in attributing the adjustment to the action of the corpus ciliare ; the latter considering that, \u201c by the graduating power of the ciliary processes and ciliary muscles, together with the elasticity of the membranes of the vitreous body, the crystalline may be drawn not only backwards and forwards, but its inclination may be changed so as to throw the image on another part of the reretina and the modus operandi be explains by supposing \u201c the outer ciliary muscle to contract the vessels returning from the ciliary processes ; the ciliary processes which are attached by the filaments of Ammon to the ciliary zone and crystalline capsule, to become erect and to draw forward the crystalline body ; and the inner ciliary muscle, aided by the elasticity of the membranes of the vitreous humour, to draw it backwards.\u201d\nThe opinion, however, which appears most satisfactory, is that advanced by Mr. Bowman, who has clearly proved the muscular nature of the ciliary body. \u201c It has (says he) the arrangement of a muscle, very much the structure of a muscle, and is largely supplied with nerves, which are in great part derived from a motor source \u2014 the third pair. This muscle arises, or has its most fixed attachment, at the junction of the sclerotica and cornea, as much in front of the lens as is possible, consistently with the preservation of the transparency of the cornea. That it may act more freely, a canal, the circular sinus, is interposed between its origin and the portion of the sclerotica which it lies against. Beyond this point it is hardly at all attached to the sclerotica, over which its fibres may be supposed to move in contraction ; but it","page":1451},{"file":"p1452.txt","language":"en","ocr_en":"VISION.\n1452\ncovers, and is inserted into, the anterior one-eighth of an inch of the choroid membrane, which is in this part tougher and firmer than elsewhere, and united in a very special manner to the lens by the ciliary processes, through the medium of a firm tough membrane, and of a strong elastic fibrous membrane proceeding from it to the margin of the lens, and yet not quite to its margin, for an elegant arrangement exists, the canal of Petit, by which traction is made, not on the vitreous around the lens, nor on the edge of the lens itself, so much as on its anterior surface. I confess it seems to me very difficult to doubt that this complicated system of parts is intended to advance the lens towards the cornea, so as to bring forward, up to the retina, the focus of a near object, which would otherwise fall behind the nervous sheet. It is possible also, I think, from the peculiar direction taken by the ciliary muscle, that it may compress the front of the vitreous, and thus help to throw forward the lens.\u201d *\nAn ingenious theory has been suggested by Sturm, and supported by Matteuci, founded on the results of Chossat\u2019s measurement of the eye of an ox, to the effect that in place of comparing the optical apparatus of the eye to a system of spherical lenses whose axes are blended, we ought to consider the organ as composed of several refracting media, separated by surfaces which are neither exactly spherical, nor even of revolution or symmetrical about a common axis. Reasoning from this, he argues \u201cthat a peculiar refraction of the rays of light takes place, whereby tne retina is placed in what he terms a focal interval, which focal interval will change its position according as the external luminous point recedes from, or approaches to, the eye and that the retina will be always met by the concentrated fasciculus around the axis in the focal interval ; the surface of intersection of this fasciculus and of the retina being very slightly modified, in order that the impression may not be sensibly altered, or the perception rendered indistinct. This theory is, however, decidedly open to objection, and is rendered unnecessary by that of Mr. Bowman.\nMagnifying lens. \u2014 It has been already stated that the apparent magnitude of an object depends upon that of the angle of vision under which it is seen, and this increases in proportion as the object is brought nearer to the eye ; but the magnitude of the angle of vision being limited, we are obliged to resort to artificial means to enlarge it further than, in its natural condition, is admitted of. The pin-hole aperture affords some assistance, but the convex lens more. The following is the mode in which it acts :\nLet cd be a convex lens, and ab an object lying within the focal length of the glass, then all the rays passing from a point ot the object ab will diverge after their passage through the lens, exactly as if they came from the corresponding point of the image ab ; an eye\n* Lectures on the Parts concerned in the Operations on the Eve, p. 60.\nFig. 889.\na\nbehind the lens would be able to see the object distinctly through the lens if the image ab were at the distance of distinct vision. In this case, however, the object being much nearer the eye, it could not be seen without the lens. The magnifying power of the lens therefore depends essentially on the means it gives us of bringing the object very near the eye, and thus increasing the angle of vision.\nAbnormal Vision.\nIn the consideration of abnormal vision, we propose to divide the subject into\n1.\tAbnormal Vision resulting from defective action of the retina or sensorium ; as Achromatopsy, Hyper chromatopsy, and Anorthopia.\n2.\tAbnormal Vision arising from faulty configuration of the eye, or from changes in the refractive media ; as Myopia, Presbyopia, and Cylindrical Eye.\nAmaurosis, Chrupsia, and other morbid conditions, do not fall within the scope of this article.\nAchromatopsy \u00c7a not, xP\u00aelJLa colour, \u00dcnp the eye), or insensibility of the eye to colours, is an affection which has been recognised nearly two hundred years ; but, although cases have been from time to time published in the Philosophical Transactions and other scientific works, our knowledge of the phenomena of this singular condition is of recent date, and is chiefly due to the labours of Wartmann, Seebeck, Szokalski, Purkinje, Himly, &c.\nVarious names have been proposed for this imperfection of vision ; but the majority are exceedingly unmanageable. By Sommer and Szokalski the term chromato-pseudopsis has been employed ; Goethe proposed to call it akyano-blepsis, whilst Purkinje divided the disorder into four varieties,\u2014achromatopsia, chrom\u00e2t o-dy sop sis, akyano-blepsis, and anery-thro-blepsis ; others again have been satisfied with the simple term chrom\u00e2t o-metablepsiS. JUngken employs indifferently the denominations of achromatopsy, chromatopseudopsy, and chromatomctablepsy. Many writers, however, have adopted the term Daltonism, proposed by Pr\u00e9vost, and supported by Wartmann ; and, although objectionable as perpetuating the infirmity of an individual, it has the merit of simplicity and easy inflection. The term achromatopsy is, perhaps, that most usually employed, although, strictly speaking, it is only applicable to one class. Still, being extensively recognised, we shall adopt it to designate this imperfection of vision ; occasion-","page":1452},{"file":"p1453.txt","language":"en","ocr_en":"VISION.\tU53\nally the expressionDaltonian\u201d may be used for the sake of brevity.\nModifications of insensibility to colours exist in every degree, and in the minor shades are so frequent as to be almost proverbial with reference to the male sex ; indeed, if twelve men, taken at random, were shown a numner of ribands of the more delicate colours, a diversity of opinion would almost certainly arise as to the appropriate names. The number of persons who cannot distinguish certain colours is considerable ; but the defect is seldom known to others, those who are conscious of their imperfection being desirous of concealing it, and some perhaps, not being aware of it till accident leads to its discovery. In every case that has fallen under our notice, there lias been reluctance to submit to examination, from the fear of ridicule ; and indeed it is difficult to repress a smile when a person is seen to match green and scarlet together, or crimson and dark blue, and earnestly protest that the colours are absolutely identical. The nearest approach to this condition in the healthy eye, and a test by which the embarrasment of Daltonians may be judged of, is the difficulty of distinguishing between blue and green by candlelight ; a difficulty which every one must have experienced. Analogous to this defect of the organ of vision, is that better known, because more evident, insensibility of the organ of hearing, whereby many persons are utterly unable to detect the differences between musical notes, or, as pointed out by Dr.Wollaston, their ears maybe absolutely insensible to sounds at one extremity of the scale. Sir David Brewster remarks* that, although his own hearing is perfect and each ear equally acute for all ordinary sounds, yet one of them is absolutely deaf to the chirp of the cricket, while the other hears it distinctly. Dr. Pliny Earle has published + a remarkable illustration of the imperfection of the two senses in conjunction. \u201c The whole family (says he) of which the chart has been exhibited, is probably no less generally characterised by a defective musical ear than an imperfect appreciation of colours. * Several of the individuals comprised in it are utterly incapable of distinguishing one tune from another. *\t* A gentleman who has the general defect\nunder discussion, and whose case is included in the thirty-one herein mentioned, is a well-known professor in one of the Metropolitan Medical Schools of the United States. In him the total inability to discriminate between musical sounds is coexistent with the defective perception of colour *\t* Another\nof the gentlemen whose case of defective perception of colours is herein noticed, is generally acknowledged as one of the first and greatest of American poets now living. He also is unable to distinguish one tune from another ; yet his poetry is not deficient in the requisites of perfect cadence, harmony, and rhythm.\u201d\n* Philosoph. Mag. vol. xxv. p. 136.\nf American Journal of Medical Sciences, vol. 35. p. 347.\nIt has been remarked by Wartmann as a curious fact, that in no ancient author is there any passage which can be referred to the subject of achromatopsy, and that the numerous travellers who have traversed the old and new world are equally silent in this respect.\nAs to the relative frequency of achromatopsy, Seebeck states that five out of forty youths who composed the two upper classes in a gymnasium at Berlin, were affected with it, and Pr\u00e9vost has declared that the proportion of this imperfect vision to perfect vision, is as one to twenty. It is true that Chelius and Chevreul entertain a very opposite opinion, .but the balance of authority is decidedly against them.\nThis affection is often hereditary, and is found in some families to a remarkable extent. It sometimes occurs in successive generations, of which a remarkable instance has been published by M. Cimier *, and at other times it appears in alternate generations, descending far more frequently on the maternal side than the paternal. In the case of Mr. Milne, recorded by Dr. Combef, the maternal grandfather was affected with Daltonism, also his two brothers and a second cousin. In that of a child related by Dr. Nicholl J the maternal grandfather and several of his brothers were similarly affected ; such was also the case with two young men mentioned by Dr. Cornaz.\u00ff They were the offspring of the same mother but by different fathers, and in both, achromatopsy existed to a marked degree. But the most striking illustration of the hereditary character of this defect has been recorded by Dr. Pliny Earle ||, and it is so remarkable that we give it in his own words. \u00ab My maternal grandfather and two of his brothers were characterised by it, and among the descendants of the first mentioned, there are seventeen persons in whom it is found. I have not been able to extend my inquiries among the collateral branches of the family, but have heard of one individual, a female, in one of them, who was similarly affected.* * * Nothing is known of the first generation (of five) in regard to the power of perception of colours. In the second, of a family consisting of seven brothers and eight sisters, three of the brothers, one of whom, as before mentioned, was the grandfather of the writer, had the defect in question. In the third generation, consisting of the children of the grandfather aforesaid, of three brothers and four sisteis, there was no one whose ability to distinguish colours was imperfect. In the fourth generation, the first family includes five brothers and four sisters, of whom two of the former have the defect. In the second family there was but one child, whose vision was normal. In the third there were seven brothers, of whom four had the defect. In the fifth, seven sisters and three brothers, of all of whom the\n* Annales d\u2019Oculistique, tom. i. p. 417.\nt Transactions of Phrenological Society, p. 222\nt Med. Chir. Trans, vol. vii. p. 477.\n\u00a7 Annales d\u2019Oculistique, tom. xxiii. p. 43.\n|| Op. cit. p. 349.","page":1453},{"file":"p1454.txt","language":"en","ocr_en":"VISION.\n1454\nvision is perfect in regard to colour. In the sixth, four brothers and five sisters, of whom two of each sex have the defect. In the seventh, two brothers and three sisters, both .of the former having the defect. In the eighth, there was no issue, and in the ninth there a e two sisters, both of them capable of appreciating colours.\u201d Of the fifth generation \u201c the defective perception has hitherto been detected in but two of the families. In one of them, consisting of three brothers and three sisters, one of the brothers has the defect, and in the other, a male, an only child, is similarly affected.\u201d\nSex exercises a considerable influence on the occurrence of achromatopsy ; of the thirty-one cases mentioned by Dr. Earle, twenty-seven were males and four females, and the result of upwards of two hundred cases shows that as a general rule the proportion of males is nine tenths of the whole. A very remarkable instance has however been published by M. Cunier*, where achromatopsy occurred in five generations of one family, there being thirteen cases, and all females ; but this stands alone as a notable exception to the general rule. If it be true that the works of the needle are the means of perfecting a delicacy in the judgment of tints, and in women the organ of colour is more developed than in men (as asserted by Gall), these very works ought to lead daily to the detection of achromatopsy if it existed ; and we may reasonably conclude that as cases are not discovered they do not exist.\nAccording to the observations of Szokalski, this defect of vision especially obtains among nations having a Germanic origin, as the Germans, English, Swiss and Belgians ; the French, Italians, and Spaniards being comparatively free : it seems to be common in the United States, but this does not militate against the proposition, the Americans being descendants of the old British stock. How far this peculiarity may be attributable to the greater sensibility of the inhabitants of southern climes, where the more brilliant sunshine develops colours in a degree unknown in the northern latitudes, is a question which cannot be decided in the present state of our knowledge: nor can we affirm with confidence, as stated by the same writer, that achromatopsy occurs most frequently in robust constitutions, combined with a bilious and melancholic temperament. A difference of opinion exists as to whether achromatopsy is indicated by any visible signs ; Szokalski, Ruete, and Himly affirm that there is no diagnostic mark, and Rau considers that a yellowish tinge of the iris, which has been considered by some to be indicative of it, is far too common to be so regarded. Professor Wartmann has in his first memoir drawn attention to a peculiar golden lustre of the eyes, which presents itself in cases of achromatopsy, where the iris is hazel. Miss Sedgwick f says of the historian Sismondi, that he\n* Op. cit.\nj- Letters from Abroad, vol. i. p. 250.\nhad brilliant hazel eyes ; he was a Daltonian. At least five other cases are known to have presented the same peculiarity, but the number is yet too small to admit of this being regarded otherwise than as a coincidence, for in truth there appears to be as many Dalto-nians with blue, black, and grey eyes, as with hazel, and as many eyes without a yellow pupillary margin as with it.\nThere is sufficient evidence before us to warrant our considering achromatopsy under two distinct forms : congenital and non-con-genital. The former is always persistent : the latter may be divided into permanent and temporary.\nWriters have classified the defect according to degree; but the simplest and most practical arrangement is that of Wartmann, who recognises two classes only : the Dichromatic and the Polychromatic. This we think advantageous, as avoiding unnecessary sub-classification, the varieties of the defect being endless.\nCongenital Achromatopsy. \u2014 This form is most common, and the majority of recorded cases of insensibility of the eye to colour are examples of it. It presents the best marked illustrations of both varieties, which we shall proceed to consider.\nClass I. (Dichromatic Daltonism of Wartmann).\u2014 Black, white, and the intermediate shades of grey are the only tints recognized by patients of this class. Such persons distinguish with facility the forms of objects and the gradations of light and shade, but to them all the charms of nature and of art, as expressed by colour, are unknown ; their retinae are rather sensitive than otherwise, and they not only see objects at a great distance, but can read with facility in an obscurity amounting to darkness.\nThe first of these cases on record was published by Dr. Dawbeny Tubervile, an oculist of Salisbury,* being that of a young woman who consulted him about her sight, which, though excellent in every other respect, incapacitated her from distinguishing any other hues than black and white ; it is especially mentioned that she could read \u201c for nearly a quarter of an hour in the greatest darkness.\u201d The next, best marked case has been recorded by M. D.\nHombres Firinas.f M.----------, of Anduze, of a\nbilious and melancholic temperament, but leading a very active life, had arrived at an advanced age without its being known, except to a very few individuals, that there was anything uncommon in his sight ; but all colours appeared to him as tints of grey, between black and white. Like several others having this infirmity, he was fond of painting, and had painted in his apartment two friezes and a pannel between the windows: of these he was proud ; but some of his visitors inquired why he had represented the ground, the trees, houses, and persons all blue ? He replied that he wished them to match the furniture, he\n* Phil. Trans. No. 164. p. 736. and Lowthorp\u2019s Abridgement, vol. iii. part i. p. 40.\nf Ann. d\u2019Oculistique, tom. xxii. p. 72.","page":1454},{"file":"p1455.txt","language":"en","ocr_en":"VISION.\nbeing quite unconscious that this was red. He had a collection of engravings, some coloured and others plain, but the only difference he could perceive was, that some were clearer than others. When criticising a picture he would discuss the composition of the design, the light, shade, and perspective ; but, as to the colours, he was silent. When walking with others in a garden, he affected to speak of the beauty and size of the flowers, their regularity and perfume, but to his eyes they, like the pictures, were all grey. The case of a shoemaker named Harris, described in the Philosophical Transactions,* * * \u00a7 has been generally quoted as a well-marked example of this form of achromatopsy, but on carefully considering the remarks made upon it by Dr. Dalton j', we are doubtful whether it really was as supposed, and are inclined rather to refer it to the second class.\nThe case of M. Collardeau | has been described as of this nature. This gentleman was an amateur artist, but the imperfection of his vision gave rise to the strangest productions. So long as he confined himself to the pencil, or to sketching in one colour, he designed with much skill, but his paintings in colours were the reverse of happy. For instance, wishing to work up a scene in which he had drawn a dog, he unfortunately mistook the colour, and painted red all those parts which should have been deep blue. He has been known to confound on the canvass yellow with blue, and red with green, regarding his work with the complaisance of a man who felt that he had achieved success.\nThe following interesting cases are of a character forming a connecting link between the two classes of achromatopsy. The first is related by D\u2019Hombres Firmas.\u00ff Count\n-----of Alais, aged thirty -eight, married,\nand the father of a family, possessed excellent vision in every repect, except the perception of colours ; but yellow, and the shades between black and white, were the only tints he could recognise. On a number of different roses being placed in his hands, he merely saw that white flowers were brighter than purple; yellow flowers he distinguished, but red, blue, violet, and white blossoms all appeared more or less dark though he distinguished the yellow centres. This gentleman was fond of geology, but found it impossible to judge of the colours which marked various formations in the map of M. Dumas. Lacustrine formations and the lias were the only ones which he distinguished, all the others appearing to him tinted in grey; and he would have confounded them together, if his excellent sight had not enabled him to follow the dotted lines and letters by which they were indicated. He drew with taste in crayon, Indian ink, and sepia ; but only on\n* Phil. Trans, vol. Ixvii. p. 260.\nf Memoirs of the Literary and Philosophical Society of Manchester, vol. v. parti, p. 38.\n{ Observations sur la Physique et l\u2019Histoire Naturelle, vol. xiii. p. 87.\n\u00a7 Op. cit. p. 73.\n1455\none occasion attempted a scene in colours, of a peasant and a bouquet of flowers. The result was so very unsatisfactory to ordinary eyes, that he was not tempted to repeat the experiment.\nThe second case has been recorded by Dr. Deconde.* A soldier applying for his discharge on the ground of the formation of cataract, attracted particular attention on account of the cyanic colour of his sclerotica ; and on investigating his power of distinguishing colours, it was found that all those of the spectrum were confounded in two fundamental hues, yellow and blue. Dark red, bright red, rose, orange, yellow, green in which yellow predominated, and grey white, all appeared as different shades of yellow : whilst blue, green, and white with a blueish shade, were perceived as blue. All the very deep colours were regarded as black, and *all the very light ones had a whitish appearance, though the man did not seem to have cognizance of white, properly so called. Light, decomposed by a prism, appeared to him of uniform blue. His sight was feeble and easily fatigued. Numerous trials always led to the above results.\nClass II. (Polychromatic Daltonism of Wartmann.)\u2014This form includes the vast majority of cases of insensibility to colours, and presents a very remarkable diversity of phenomena. The colour, which, of all others, is the stumbling-block, is lilac, and next to it rose, indigo, and violet; on the other hand, yellow and blue are most commonh recognised. A very general form is that first described by the illustrious Dalton f, who has given his name to the affection; and the following are the chief features of his case. He was not conscious of any peculiarity of vision until the age of twenty-six, when, a discussion arising as to the colour of the flower of Geranium zonale, it was discovered that he and his brother differed materially from other people in their ideas upon the point. About two years afterwards he entered upon an investigation of the subject, and the following are the principal results at which he arrived. The solar spectrum appeared composed of three colours, yellow, blue, and purple, the red being little more than a shade or defect of light. Orange, yellov.', and green were shades of yellow, whilst green and blue were strongly contrasted. Of ordinary colours, crimson and dark blue w\u2019ere identical ; the colour of a florid complexion being a dull opaque blackish blue, upon a white ground ; blood seemed bottle green ; the face of a laurel leaf was a good match for a stick of sealing wax ; and the back of the leaf answered to the lighter red of wafers. Green baize appeared a dark brownish red ; and a light drab was not to be distinguished from a light green ; browns were very diversified, some having a great affinity for green, others\n* Annales d\u2019Oculistique, tom. xx. p. 52.\n% Mem. of the Lit. and Phil. Society of Manchester, vol. v. part i.","page":1455},{"file":"p1456.txt","language":"en","ocr_en":"1456\tVISION.\nfor red; pink appeared sky blue by daylight, but assumed an orange or yellowish appearance by candle light. Dalton believed that the peculiarity in his vision was caused by the vitreous humour of his eyes having a blue tint : to this point reference will hereafter be made.\nAccording to Professor Wartmann, the following are the most common confusions of colour, ranged in order of their frequency : \u2014\n1. Deep red with deep blue.\nIndigo with violet.\nDeep blue with violet.\nBright orange with bright yellow.\n5. Deep brown with deep green.\nDark blue with indigo.\nBright brown with bright green.\nDark red with dark green.\nRose with bright blue.\n10. Dark orange with dark yellow.\nBright red with bright green.\nDeep yellow with dark green.\nDai\u2019k brown with black.\nBright red with bright blue.\n15. Bright yellow with bright green.\nBright red with bright yellow.\nDark red with black.\nDark red with dark brown.\nDark green with violet.\n20. Dark red with dark yellow.\nDark red with violet.\nBright yellow with bright brown.\nBright blue with violet.\n25. Dark red with dark grey.\nDark red with indigo.\nRose with violet.\nDark blue with dark grey.\nDark green with indigo.\n30. Rose with dark blue.\nRose with indigo.\nDark green with dark grey.\nBright orange with bright green.\nWhite with faint green.\nPutting aside the differences in the brilliancy of the tints, it is found that the following numbers express how many times each of those tints is proportionally seen without error.\nRed -\t-\t37\tBlue\t-\t-\t100\nOrange -\t-\t12\tIndigo\t-\t-\t0\nYellow -\t-\t100\tYiolet\t-\t-\t0\nGreen -\t-\t59\nWartmann has given* a very interesting account of his experiments on the vision of Louis D-------. This individual did not per-\nceive any great difference between the colour of the leaf and that of the ripe fruit of the cherry ; he confounded that of a sea-green paper with the scarlet of a riband placed close to it. The flower of the rose seemed to him greenish blue, and he called the ash colour of quick lime light green. The appearances presented by a solar spectrum were as follows,\n___the coloured bands, brilliant and distinct,\nextended a length of about 0-102'. D--------------\nperceived four colours only, blue, green, yellow and red. He limited the blue part exactly to the space occupied by the violet, indigo and blue : he called the green and yellow bands, less an interval of 0-002' towards the orange,-green ; he called that band of 0 002 , and a fraction of the red 0-012' in breadth, yellow;\n* Taylor\u2019s Scientific Memoirs, vol. iv. p. 173.\nlastly, the remaining 0'008' of red appeared to him of a red difficult to define. By refracted light the results were nearly the same, thirty-seven plates of glass exhibiting only four different colours in various intensities.\nWhen examined by polarized light, it seems that on the one hand he did not appreciate the equality of intensity of two complementary colours as did ordinary vision ; but he found a total and abrupt difference when colours passed at once from the finest red to very rich deep blue, a distinction far from being marked to others.\nHis visual organ was unable to perceive the different mixtures of red which accompany blue to make it pass into purplish violet. This precise circumscription of the constitutive domain of a colour is a fact which, in the opinion of Professor Wartmann, was new and worthy of being remarked.\nWhilst a series of these experiments with olarised light were going on, the sun, which ad been obscured, suddenly shone out, and D------ declared that the colours imme-\ndiately assumed a different tint to his sight, all reddening in a sensible manner, so that he called red that which he had before named green and ill-defined blue, whereas the Professor saw no other change in the colours than an increase of their brilliancy and strength.\nWartmann then submitted the patient to experiments to ascertain his perception of the complementary colours, and the result showed that although his eyes were not insensible to them, the colours which appeared to him complementary were not the same as those so regarded by the normal eye. The Professor then painted a human head, giving to each part a complementary colour. Thus the hair and eyebrows were white, the flesh brownish, the sclerotica black, the lips and cheeks green. When asked what he thought of the bead, D------ replied that it appeared to him na-\ntural, that the hair was covered with a white cap little marked, and that the carnation of the cheeks was that of a person heated by a long walk.\nThere are a certain number of cases of insensibility to colours which have been quoted by all writers on the subject. We shall therefore content ourselves with merely referring to them*, describing a few well marked and uncommon instances less generally known.\nDr. Boys de Loury f has published the\nparticulars of a M. H------, who was obliged,\non account of his defective sight, to abandon the profession of a dyer. His principal colour was yellow. The brilliant yellow of the apricot and deep brown of the chesnut were only distinguished as varieties of shade. All dark hues were called black; scarlet ap-\n* Cases of achromatopsy are detailed as follows : \u2014 Phil. Trans, vol. lxvii. p. 260, vol. lxviii. p. 611 ; Edinb. Phil. Trans, vol. x. 253 ; Spurzheim Phrenology, 3d ed. p. 276 ; Combe\u2019s Syst. of Phrenology ; Trans. Phren. Society, p.222 ; Trans. Med. Chir. Society, vol. vii. p. 47 7, vol. ix. p. 359 ; Glasgow Med. Journal, vol. ii. p. 12; Edinb. Phil. Journal, vol. vi. p. 135.\n, f Revue M\u00e9dicale, Nov. 1843.","page":1456},{"file":"p1457.txt","language":"en","ocr_en":"VISION.\n1457\npearecl as a blue grey, rose colour dirty white ; orange, pure yellow ; apple green, yellow ; lilac, blue ; violet, grey. There was no unusual appearance in his eyes, but he saw most perfectly in the evening.\nDr. Sommer* has described his own case thus. Blue can always be distinguished from yellow, bright blue from green, and deep red from black, but green and dark blue are often confounded. Yellow, black, and decided blue are the fundamental colours. If he holds a leaf of a tree and a stick of red sealing-wax side by side he recognises distinctly the diff\u00e9rence in intensity between the tw\u2019o colours, but cannot affirm which is green or which red : rather decided blue and rather intense red bear a great resemblance; blue is confounded with red, green with brown, brown and orange with bright brown. As to crimson, lilac, purple and deep scarlet, they are colours of which he cannot form even an idea. He one day met a lady wearing a blue bonnet ornamented with red roses, but could scarcely distinguish any difference between the two. On another occasion when walking out it began to rain. \u201c Then (says he) a crowd of red umbrellas displayed themselves, and I compared the colour to the azure of the sky.\u201d The rainbow appeared to him composed of blue and yellow ; he knew that there were shades, but could not satisfactorily discern them.\nThe case of the late Mr. Troughton was examined by Sir John Herscbell and Sir D. Brewster, and it was ascertained that he saw the red space yellow ; hence according to the views of Sir D. Brewster, he saw a space containing much yellow, and little blue, the red light being as it were absorbed in consequence of the retina being insensible to its action. Sir D. Brewster goes on to say j\", \u201c If this be the case there must have been a diminution of light in the red space seen by Mr. Troughton, and I am persuaded from the experiments I made upon his eyes that this was the case ; but whether it was to the extent of the total defalcation of the red rays, I will not venture to assert. But it is not necessary that it should be so ; the defective perception of red light may be accompanied with a more acute perception of the other colours, in a manner analogous to what takes place in the chemical spectrum, where the removal of the red rays produces an increased action of the rays that are left.\u201d Sir D. Brewster, adds that he has long been of opinion that the retina receives a more powerful luminous, impression from yellow light than from the cure white light of which this yellow forms but \u00e0 part.\nPersons affected with achromatopsy not only see well in deep gloom, but their vision of distant objects is particulaily sharp, from the azure blue of the atmosphere presenting the strongest possible contrast to black. One intelligent person saysj, \u201c So much is this the\n* Graefe und Walthers, Journal f\u00fcr Chirurgie, Bd. v. Heft i. S. 135.\nf Phil. Mag. vol. xxv. p. 139.\nJ Glasgow Medical Journal, vol. ii. p. 12.\nVOL. IV.\ncase with me when viewing a distant object as to overcome the effect of perspective ; and the shading in the form and garments of persons at a distance is often so predominant as to overcome the effect of diminution in size ; and although, I see the object most distinctly, I am unable to tell whether it be a child near me or a full-grown person at a distance.\u201d\nDaltonians endeavour to obviate the annoyances arising from their infirmity by taking some standard colours or shades as points of comparison, as for instance the green of grass ; they also bring the sense of touch to their assistance, and are enabled by these means, united with close attention, to avoid many errors ; but nevertheless they feel repugnance to express an opinion upon colours\nNon-congenital Achromatopsy.\u2014This though quite distinct from Chrupsia, is generally a morbid symptom, and might easily be confounded with it. It is to be borne in mind that in certain cases of chrupsia objects appear tinged with colours foreign to them ; a general officer for instance saw all white objects of a deep orange colour at certain times of the day, and to a lady they appeared of a bright blue*; but in such cases all objects are tinged with a prevailing tint or it is confined to those which are white, coloured objects being properly recognised. In achromatopsy one or more colours are effaced, and the individual is no longer cognizant of them.\nPermanent Achromatopsy. \u2014 A bootmaker in Paris f, was attacked with amaurotic amblyopia, which followed suppression of the cutaneous exhalation. It was accompanied with rheumatic pains, and there was at first irritation of the retina, but this subsided, leaving the sight imperfect. The patient, however, assured M. Szokalski that he had possessed a full perception of colours until after a copious bleeding from the arm. From that time he could only discern white, black, and grey, and could not distinguish an engraving from a coloured print. He one day bought a piece of yellow morocco leather by mistake for a white piece, and when examined by M. Szokalski, he could not distinguish any coloured patterns which were exhibited to him.\nI)r. Mackenzie thus writes : \u201c I always considered this affection as a congenital one, till I was consulted by a man who had gradually become subject to it. He was by trade an ornamental painter, and could judge at one time perfectly of colours. His right eye was affected with mydriasis when he called upon me, and there was incomplete amaurosis of both eyes, so that he could no longer read a common type. On trying him I found he mistook red and green. The use of spirits and tobacco was probably the cause pf the affection of sight in this individual.\u201dJ\n* Collections from the unpublished medical writings of C. H. Parry, M.D. vol. i.\nt Ann. d\u2019Oculistique, tom. iii. p. 200.\nX Practical Treatise on Diseases of the Eye, 3rd edition, p. 799.\n5 A","page":1457},{"file":"p1458.txt","language":"en","ocr_en":"VISION.\n1458\nWartmann * has related a case supposed not to have been congenital; this, however, is uncertain; the particulars are interesting, especially as valuable information, to which we have referred, was obtained from this patient.\nM. Louis D---------was the eldest of seven\nbrothers and four sisters, who were assorted in a very singular category. The first set had red hair, and their vision was perfect ; the others had fair hair, and all were unable to\ndistinguish colours. Louis D---------- belonged\nto the latter, as regards external appearances, but according to his own recollection, and the evidence of his mother, he perceived colours during his infancy, in the usual manner. At the age of nine years his skull was fractured, after which his perception of colours appears to have become defective. The fact however of his brothers, who resembled him in appearance, being similarly affected from birth, weakens the chain of evidence on this point. His infirmity was for some time unknown, and his father endeavoured, by repeated corporal punishment, to put a stop to what he called a perverse pretence, and a severe correction was administered by his master, a bookbinder, because he used red paper, instead of green, for the covers of some books.\nTemporary Achromatopsy. \u2014 This form appears to us not to have received the attention it merits, having been passed over in silence, or only cursorily alluded to, by the great majority of writers. The exciting causes are congestion, hepatic derangement, and dyspepsia, and it may exist in conjunction with more or less amaurosis, or by itself, as a simple derangement of vision.\nThe first case we shall relate is highly interesting from the marked manner in which the insensibility to colours existed, its duration and satisfactory disappearance as restoration to health proceeded. It occurred in the practice of that very able physician, Dr. Hays.f\nMary Bishop,, \u00e6tat. twenty, was admitted into the Wills Hospital, Feb. 9, 1839. She was of short, robust stature, full habit, very dark complexion, black hair, and hazel irides, flushed face, colour of her cheeks at times almost of a purplish hue ; catamenia suppressed. In 1837 and 1838 she had suffered from two attacks of cerebral disease ; after the first attack, objects appeared double. The second attack left her entirely blind, in which condition she continued for four months. After this her sight began to return, and at the period of her admission into the hospital, she could read large print. When she came under the notice of Dr. Hays, in May, 1839, she had been largely depleted, and had taken remedies for the restoration of the catamenia, under which treatment her sight had improved. At this time it was discovered that she was unable to distinguish colours, yellow and blue being the only ones she could name with certainty. Nearly all others she termed brown, or hesitated to name, designating how-\n* Op. cit.\nt American Journ. of Medical Sciences, vol. xxvi. p. 277.\never their shades, or intensity of colour accurately. Thus she called a deep red, dark brown ; a bright green, light brown ; and very pale pink, very light shade of brown. The patient was not sensible at first that she laboured under any particular defect in distinguishing colours. She had noticed, that grass and roses did not appear as formerly, and she remembered that as her sight began to return, the first colour she perceived was yellow. The usual treatment for amenorrhea was adopted, and on the 29th of May the catamenia returned copiously, but continued only for a single day. It was followed, however, by a very marked improvement in vision. Roses now appeared to her of their natural colour, and she could distinguish the difference between the colour of the rose and that of the leaves, which she had not previously been able to do. By the middle of June she was able to see the eye of a needle and the end of a thread, but could not thread the needle from inability to see both at the same time. At this period she was again examined with the prismatic spectrum, and distinguished pretty accurately the yellow, blue, green, and red, but was doubtful as to the orange. On the 30th of November it is stated that her sight was good, notwithstanding another attack of congestion and suppression of the menses. She distinguished all the primitive colours readily, and named most of the secondary ones as correctly as could be expected, with the exception of violet, which she was at a loss to name.\nA gentleman, aged 36, librarian to one of our medical colleges, has communicated to me the particulars of his own case in the following words : \u201c A few years ago I noticed that on getting out of bed, and looking at a new carpet which had been laid down but a short time, I was unable to distinguish the colours, though I could clearly make out the pattern, which appeared simply black and white. I felt rather alarmed, and asked my wife if it was the same carpet. She assured me it was, and inquired mv reason for putting the question. On telling her, she at once suspected I had taken some bad wine at a public dinner I had attended over-night. I may add that I have invariably experienced the same effects after dining out, more especially if I take more than one kind of wine ; and of this I take but little, in consequence of the severe illness I experience on the following morning. If I take grog or punch, the symptoms, including the loss of power of seeing colours, are still more severe.\u201d\nSimple congestion of the head and eyes, especially when accompanied with fatigue, is also an exciting cause of achromatopsy. Ruete states, that a girl suddenly lost the faculty of distinguishing colours as a consequence of congestion ; and we have known instances produced by exhaustion.\nA clergyman, 45 years of age, of full habit, but enjoying good health, was performing Divine service in the month of June, 1851, and felt fatigued and oppressed by heat and the","page":1458},{"file":"p1459.txt","language":"en","ocr_en":"VISION.\t1459\nclose atmosphere of the church. At the conclusion of the service, on rising from the kneeling posture, he was alarmed at finding that the crimson velvet cushion and hangings of the pulpit appeared of a dark violet hue, and that other familiar objects which he knew to be red, had likewise changed to bluish green ; there was at the same time some giddiness and discomfort in the head. Having rested in the vestry about ten minutes, the symptoms gradually passed away, the crimson objects becoming less and less blue, and the red objects gradually resuming their proper colour. Aperient medicine, &c., was prescribed, and we are not aware of any other attack having been experienced.\nAnother case occurred during the great Exhibition in Hyde Park. A stout plethoric farmer, aged 52, visited London, and had undergone much fatigue and excitement in seeing the various objects of interest. On the third day, after spending some hours in the exhibition, he felt giddy and oppressed, and remarked that the crimson hangings appeared of a dull brownish green. This led him to notice other objects, and he ascertained that he could no longer discern the difference between reds and greens generally, though yellows and blues retained their proper colour. On his leaving the building, the uniform ot the footguards and the colour of the folia'ge of the trees, nearly assimilated. When he reached home, he slept for three hours ; and on awaking, was much relieved at finding that the power of discerning colours had returned.\nThe extraordinary variety and glare of colours at the exhibition was singularly distressing to the eyes, and numerous persons suffered from congestion of the choroid in consequence.\nAccording to M. Cunier, temporary achromatopsy almost always constitutes one of the symptoms of congestive amblyopia in persons affected with hemorrhoids and venous congestion of the abdomen. The confusion between the sensations of red and blue, takes place every time that the encephalo-ocular turgescence is augmented by the effect ot a lively emotion, anger, a rapid walk, too great application of the eyes, &c.* That eminent oculist relates the following case. He was consulted by an officer of artillery, who suffered in a slight degree from congestive amblyopia. Every time that he performed man\u0153uvres, and fatigue increased the cerebro-ocular congestion, the men appeared dressed entirely in blue ; the white waistbelts he distinguished, but the red worsted epaulets, the red tuft of the shako, the facings of the coat and red stripes down the trowsers, appeared blue. He could see that the shako and trowsers were of black cloth. A brief repose, with cold water to the eyes and forehead, soon restored natural vision.\nAn interesting example of temporary achromatopsy, doubtless the effect ot congestion,\nis related by Professor Wartmann. M Thury, an ex-professor of botany in the academy of Lausanne, had walked during the night from Geneva to Nyon to witness a magnificent aurora borealis, which shone on the night of the 17th and 18th of November, 1818. To his great surprise and disappointment, he could not discern any difference between the blue of the sky and the magnificent blood colour of the aurora, which was viewed with rapture by all around. Singular to say, another lady of Geneva, a septuagenarian, presented precisely the same peculiarity, though both she and the professor had distinctly seen manv previous auroras.\nThe fallowing case, which occurred under our own observation, is an example of temporary achromatopsy caused by vitiated blood circulating through the brain and retina, and disturbing the functions of those organs : \u2014\nMr. H., a solicitor aged 37, of a spare make and melancholic temperament, is frequently subject to attacks of congestion of the liver followed by vomiting and purging of bile. These attacks are ushered in by dull pain in the head and tenderness of the eyeballs, rendering motion of them distressing. At such times he is quite incapable of distinguishing colours, all objects being simply divided into two classes, black and white with their intermediate shades of grey. The vision of objects continues perfectly distinct, but it is not until the portal system has been relieved that the perception of colours is recovered, and then yellow is the first distinguished. If however he takes five grains of calomel, the attack is cut short and the power of discriminating colours at once restored. There is nothing whatever unusual about his eyes, and under ordinary circumstances he possesses perfectly natural vision.\nAchromatopsy may be the result of injury, as in the following case related by Dr. Boys de Loury.* An individual was struck by a pistol ball which entered his mouth without touching the tongue and broke through the hard palate and base of the orbit. After his recovery from the wound, the injured eye retained but little sight ; only a small spot of the retina was sensible to light, and to use this, the eye was obliged to be thrown considerably to one side. Then objects were seen distinctly but without colour. This person described a palette spread with colours, as a plate with many holes, and confounded the thumb opening with the spots where the colours were placed.\nVarious explanations, differing widely, have been offered to account for the insensibility of the eyes to colour ; and we may remark that the subjects of this affection have in several instances been men of intellectual eminence. As for example, the metaphysician Dugald Stewart, Dr. Dalton the illustrious chemist, Mr. Troughton the eminent optician, Dr. Sommers, Dr. Unzer, of Altona, and Professor Brandis. The opinion\nOp. cit. p. 49.\n* Kevue M\u00e9dicale, Nov. 1843.\n5 a 2","page":1459},{"file":"p1460.txt","language":"en","ocr_en":"1460\nVISION.\nadvanced by Dalton and supported with the ability for which he was remarkable, was this : \u201c It appears therefore almost beyond a doubt that one of the humours of my eye and of the eyes of my fellows, is a coloured medium, probably some modification of blue. I suppose it must be the vitreous humour : otherwise I apprehend it might be discovered by inspection, which has not been done.\u201d * * * \u00a7 .Before his death, the great chemist had requested his friend Dr. Ransome to examine his eyes after his demise; this was done most carefully, and it was ascertained that though the crystalline lens had the slight yellow tinge common in old persons, the vitreous humour of both eyes was absolutely colourless. Nevertheless the hypothesis has been revived by Dr. Trinchinetti'j', who considers that the defect is produced by a coloration of one or more of the transparent media of the eye, and probably of the crystalline lens, and even goes so far as to advise depression or extraction of the lens as a means of radical cure !\nGoetheJ: attributed the confusion of colours to an insensibility to blue ; whereas Szokalski expressly states $ that among more than sixty cases of achromatopsy, of which he had notes, there was not one in which there was absolute deficiency of the perception of blue. Others again have supposed that the retina itself has a blueish tinge in such cases, whilst Dr. Thomas Youngj| attributed achromatopsy to the absence or paralysis of those fibres of the retina which are calculated to perceive red.\nThe able metaphysician Dugald Stewart T, has viewed the subject from a different point. \u201c in the power (says he) of conceiving colours, too, there are striking differences among individuals. And indeed I am inclined to suspect that in the greater number of instances the supposed defects of sight in this respect ought to be ascribed rather to a defect in the power of conception. One thing is certain, that we often see men who are perfectly sensible of the difference between two colours when they are presented to them, who cannot give names to these colours with confidence when they see them apart, and are perhaps apt to confound the one with the other. Such men, it should seem, feel the sensation of colour like other men when the object is present, but are incapable (probably in consequence of some early habit of inattention) to conceive the sensation distinctly when the object is removed.\u201d\nThis explanation would have weight supposing persons had rare opportunities of contrasting colours, for then their memory\n* Mem. of the Literary and Phil. Soc. of Manchester, p. 43.\nf Atti della sesta Riunione degli Scienziati Italian i, p. 712.\nJ Zur Farbenlehre, \u00a7\u00a7 111 to 113.\n\u00a7 Annales d\u2019Oculistique, tom. iii. p. 7.\n|| Phil. Trans, vol. lxxvi. p. 344.\nElements of the Philosophy of the Human Mind, p. 73.\nmight fail them, and they might feel uncertainty as to the proper appellation to be given to a tint ; but if there be one sense more than another which enjoys unbounded licence, it is that of sight ; not an hour passes that the property of distinguishing colours is not called into exercise, and in this age of high civilisation it is in perpetual activity. Nevertheless Dr. Himly has adopted the same view. It is on record however that intelligent persons have expressly declared that their infirmity arose from no carelessness on their part, as they had made many earnest endeavours to correct it.*\nBy phrenologists, achromatopsy has been attributed to imperfect development of the organ of colour ; Szokalski, though believing that there exists in the brain a portion which presides over the function of vision, and that this portion is diminished in volume in persons affected with achromatopsy, adds, \u201cWe know well that phrenologists place the organ of colour in the middle of the superciliary arch ; we have, however, examined scrupulously and with great pains many persons who have presented very decided depressions of this arch ; but despite of the best wishes in the world, we could never discover in them any trace of chromatop-seudopsy.\u201d'|'\nNeither does our own experience support the theory of the phrenologists; in two well-marked Daltoniens examined by us, the whole superciliary region was remarkably well developed.\nThe vision of the late Mr. Troughton was carefully investigated by Sir John Herschel, who instituted a series of ingenious experiments for the purpose of ascertaining, if possible, the cause of the imperfection. The result at which he arrived was, \u201c that all the prismatic rays have the power of exciting and affecting the eyes with the sensation of light, and producing distinct vision, so that the defect arises from no insensibility of the retina to rays of any particular refran-gibiiity, nor to any colouring matter in the humours of the eyes preventing certain rays from reaching the retina, but from a defect in the sensorium by which it is rendered incapable of appreciating exactly those differences between rays on which their colour depends. J\nHartmann $ is of opinion that it is by analysis that we arrive at a knowledge of objects which present themselves to our notice ; he supposes that we do not perceive them instantly, but little by little and only by examination of their distance, form and colour, which scrutiny rests on a series of changes operating on the retina, ciliary nerves, and motor ocular nerves : we do not easily recognize objects unless this succession of modifications has become habitual and takes\n* See GlasgowMedical Journal, vol. ii. p. 17 ; Op it. p.100.\t*\tV\nt Op. cit. p. 100.\nX Encyclop\u00e6dia Metropolitana, article \u201c Light.\u201d\n\u00a7 Der Geist des Menschen, S. 152. 1820.","page":1460},{"file":"p1461.txt","language":"en","ocr_en":"VISION.\nplace easily, hence achromatopsy results from a certain state of torpor and indolence of the retina and motor muscles of the eye !\nProfessor Wartmann, the most recent authority upon this subject, stated in his first Memoir that achromato[\u00efsy (or Daltonism) has its origin in a defect of the sensorium. In his second Memoir he enters at length into a somewhat different explanation of the phenomena. \u201c I admit (says he) with Harvey, Young, Jiingken, Muller, and others that its seat is in the retina, and I think that it is produced by an abnormal state of the nervous expansion, in such sort that it reacts equally under two or more differently coloured vibrations. If the vibration caused by a ray of red is identical with that engendered by a green raj', there will be confusion of these colours. This theory is independent of all systems destined to explain light. * * * The theory which explains Daltonism by an abnormal elasticity of the retina has the advantage of substituting a reasonable physical condition for a vague notion of the sensorium : besides, it is supported by facts, because the injuries which alter the ordinary constitution of the visual organ are capable of exciting, permanently or temporarily, a false perception of colours. Lastly it appears to be confirmed by the circumstance that with many Daltonians the eye sees less distinctly the red rays than those of which the refrangibility is greater. *\nThe actual seat of the phenomena of achromatopsy must, after all, remain matter of speculation, as it is one of those things incapable of demonstration. D\u2019Alembert says: \u201c It is very plain that the word colour does not designate any property of body, but merely a modification of our mind : that, for instance, whiteness and redness exist only in us, and by no means in the bodies to which we refer them by a habit in force from infancy.\u201d The knowledge that we possess of the existence of colours is derived from the evidence afforded by the thousands of persons endowed with the power of distinguishing them, and therefore we conclude that they do exist. But supposing we were all like Dalton and many others whose visual organs never appreciate red any more than the generality of eyes distinguish the calorific or actinic rays, we should then not be aware of the existence of the colour called red, which plays so conspicuous a part in the adornment of the universe ; or if some few eyes gifted with superior powers discerned it, the majority would have to admit its existence on the evidence of others, not from knowledge derived from their own eyes\nAs regards remedial measures, Wartmann and Seebeck recommend the employment of coloured glasses of a certain known tint ; suppose this tint red, the impression of a greet! body and of a red body at first the\n* Deuxi\u00e8me M\u00e9moire, p. 46. Dr. Wartmann enters at length into the discussion of this subject, but our space will not admit of our extracting his ingenious arguments.\n1461\nsame to the naked eye will be distinguished by the use of the transparent screen. Wartmann, however, admits that this method only remedies mistakes in the specific nature of colours, and not those which apply to the shades of one and the same tint. Jiingken and Chelius have recommended the use of coloured bands, bearing the name of their colour, and Szokalski has suggested that sensations of the various shades may be excited by fixing the eyes on different coloured patterns, and then on a black or white surface. But this proceeding is scarcely so likely to be productive of benefit as that recommended by Professor Wartmann.\nShould the achromatopsy result from congestion, such means should be adopted as are best calculated to subdue it; as depletion, purgatives, and low diet. IT it arises from menstrual suppression, it will be proper to prescribe emmenagogues, witli mustard pediluvia, hip baths, and such other means as are likely to restore the catamenia. Should derangement of the hepatic system be the exciting cause, a dose of calomel, followed by a black draught, will often be sufficient to remove it ; but it will be proper to follow such a prescription with alterative doses of mercurials and saline aperients, of which the Pullna and Marienbad waters are very serviceable : taraxacum with or without the nitro-muriatic acid may also be advisable.\nDyspepsia is too protean a disorder for us to attempt more than to suggest the propriety of carefully investigating the particulars of cases where the insensibility to colour can be traced to this cause, and of laying down such a plan of treatment, medical and general, as seems best adapted to the exigencies of each individual case.\nHyperchromatopsy (uirep, bet ond ; colour ; oxpis, vision). \u2014 Our knowledge of this condition of the vision which may be regarded as the opposite to achromatopsy, is at present very limited, and is chiefly derived from the publications of Dr. Sachs * and Dr Cornaz.f As we have never had an opportunity of investigating a case of the sort, we can only draw our information from these and some other sources.\nDr: Sachs is, we believe, an albino, and is in addition affected with hyperchromatopsy. The first account of this very singular anomaly of vision was published by him, and other instances have since been discovered. Professor Wartmann, of Geneva, in a communication with which he recently favoured us, thus writes:\u2014\u201c Quant \u00e0 l\u2019Hyperchromatopsie, c\u2019est une affection qui n\u2019est probablement pas extr\u00eamement rare. Je connais deux personnes qui m\u2019ont dit en \u00eatre atteintes, et j\u2019esp\u00e8re \u00eatre un jour en \u00e9tat de publier quelques recherches sur ce sujet. Cet \u00e9tat n\u2019est point n\u00e9cessairement li\u00e9 \u00e0 l\u2019albinisme.\u201d\n* Histori\u00e6 Naturalis duorum Lenc\u00e6thiopum Par-ticul\u00e6 du\u00e6. Erlangen, 1812.\n\u2022f De l\u2019Hyperchromatopsie, par le Dr. E. Lornaz. Bruxelles, 1851.","page":1461},{"file":"p1462.txt","language":"en","ocr_en":"U62\tVISION.\nThe characteristic of Hyperchromatopsy is that of attaching colours not merely to objects which, according to ordinary vision, possess them, but also to other objects which have no pretensions to them, and this to an extent scarcely credible.\nIt does not appear that the same colours always attach to the same objects with different individuals ; on this point there is considerable diversity, but as the account published by Dr. Sachs of his own perceptions is the most minute which has appeared, we shall take it as the ground of the following description :\u2014\nThe objects to which colours especially connect themselves in this condition of vision are, figures, dates, the days of the week, the letters of the alphabet, and musical notes. These colours are not all equally distinct : the clearest are yellow, different shades of pure white and blueish white ; the less clear are orange, red, dull white, dark blue, brown and green. Black only attaches itself to one of the letters of the alphabet. This morbid sensibility to colours thus displays itself: \u2014 A and E are red, but the first has more of the vermillion tint, the second most of the rose. I is white, O orange, U black, and is the only example of black ; UE or \u00dc is white, so is M and N. C is of a pale ash colour. D is yellow. F of a dull white. H a blueish ash colour. K approaches deep green. S is of deep blue, and W is brown.\nMusical notes indicated by the names of\nthe letters ^ et caetera, present generally the same colours as these ; however whilst in the alphabet, B and G appear almost colourless, the Si flat appears of an ash grey, and the Sol of an uncertain green.\nOf figures, 0 is almost transparent, of a pale and uncertain yellow, 1 of an undecided white, 2 of an uncertain tint, 3 almost ash coloured, 4 minium red, 5 yellow, 6 indigo, 7 blueish white, 8 brown, 9 almost deep green. The numbers composed of several figures take the colours of the last forming them. 0 does not change the colours of the figures to which it is joined, but gives to them a certain appearance, whilst a figure often repeated in the same number causes the colour proper to it to increase in intensity. 10, 11, 100, 110 and 111 are white; the first of them resembles white glass, the second is milk-colour, the third semi-transparent white ; the two last perfect white. 14, 24, 40, 44, 400 and 440 are red, but 15, 25, 50, 55, 500, 555 and 1000 are yellow; why the 1000 is yellow whilst 100 is white we do not understand, as the additional 0 does not account for it\nSunday, is to the eyes of this conscientious observer, white slightly tinged with yellow. Monday, another shade of white ; the colour of Tuesday is obscure and undecided. Wednesday is yellow ; Thursday is of a yellowish green, verging towards orange. Friday of a dull white, and Saturday is of a blueish ash colour.\nIt is stated that the abnormal sensations of colour are so intimately connected with\nthese objects, that some can only be seen without them by a strong mental effort, and that in the case of others this does not suffice.\nIn the present state of our knowledge we are not in a position to offer any satisfactory explanation of this singular anomaly of vision. That its seat is not in the eye but in the sensorium is however most probable, and in this opinion Dr. Wartmann concurs. More extended opportunities for observations will doubtless throw additional light on what must be regarded as a very curious subject.\nAnorthopia (\u00e0, not; \u00f4p0\u00e0s, straight ; o\\pis, vision).\u2014This is a condition of vision far from uncommon, and is characterised by the individuals subject to it being unable to discern when objects are not parallel one to the other, and is often accompanied by a want of ability to distinguish whether objects are symmetrical. Such persons are incapable of drawing objects correctly ; a house will be sketched with its proportions wrong and leaning on one side, and a figure will be equally unnatural, yet the artist wi 1 be sublimely unconscious of any defects. They are unable to discern whether pictures are straight on the walls, or blinds drawn parallel with the window frame ; Negroes are very subject to this peculiarity of vision. Nothing is more common than to see them, when marking out the ground-plan of a house, path, or boundary wall, draw the lines as awry as possible, and yet persist that they are quite straight, nor can they be convinced to the contrary. It has appeared to us that the persons in whom this condition of vision existed in a marked degree, were characterised by unsymmetrical heads and faces, but this may have been a coincidence merely.\nIn children who show evidences of anorthopia, pains should be taken to overcome it by practice and tuition. They should write upon ruled paper at first, and when subsequently writing on ordinary paper, should always be made to place it straight before them and to write across it by the hand moving on the wrist which should be a fixed point, and seldom moved. In drawing, the correctness of the lines should be ascertained by admeasurement ; and the study of geometry, perspective, and all other branches requiring attention to symmetry are calculated to be of service.\nMyopia (gva, I shut ; t6\\p, the eye), commonly called near sight, is an affection almost, if not entirely, confined to civilization.\nEvery eye, when in a state of repose, is adapted by its size, figure, and the refractive powers of its media, to the formation of a distinct image of an object presented before it, at one particular distance. This differs in different individuals; but from 12 to 20 inches may be regarded as the distance at which ordinary print is legible, the shortest distance at which it can be seen clearly and without exertion being from 6 to 8 inches. A person who brings small objects nearer to the eyes than 6 inches is considered myopic.","page":1462},{"file":"p1463.txt","language":"en","ocr_en":"VISION,\t1*63\nIt is commonly supposed that a certain visible conformation of the eye exists in connection with, and characterises myopia ; that the eye is full, the cornea prominent, the anterior chamber large, &c. : but this is by no means necessarily the case ; for it may happen that of two individuals in whom the apparent configuration of the eyes is the same, one will be myopic, the other presbyopic. It is also a popular belief that near-sight decreases with age ; such does not accord with our experience. We have repeatedly seen persons above sixty years of age as near-sighted as in their youth, and are acquainted with a lady of eighty-five, who has certainly never fatigued her eyes with work or reading, and who still uses, and has used for marly years, a No. 7. myopic glass.\nMyopia may arise from imperfection in the form, consistence, or relation of some of the refractive media ; or it may result from the loss of adjusting power. The first description may be induced by too great convexity either of the cornea or lens, or both ; by an undue density of any of the refractive media ; by a too great distance between the cornea and retina, &c. The effect is always the same, namely, to cause the rays of light to be so much refracted that, in place of being concentrated to a focus exactly on the retina\u2014a point essential to distinct vision \u2014 they are brought to a focus before reaching it. It is a law in optics that the nearer an object is brought to the eye, the more divergent are the rays proceeding from it, and consequently the greater the distance at which they will be collected in a focus by refractive media. For this reason it is that near-sighted persons habitually hold objects very close to their eyes, as by that means the image is thrown back upon the retina. One of the causes of imperfect vision in such persons, is the circle of dissipation formed on the retina by the rays after they have crossed at the focal point. This is principally produced by the circumferential rays ; and if these can be excluded, vision is rendered much more distinct. Thus it is that great assistance is afforded by looking through a pin-hole in a card, and even by holding to the eye a hollow roll of paper, or the hand partially closed. The habit of half shutting the lids which has given the name to the affection, has reference to the same object\u2014the exclusion of the circumferential rays.\nIn connection with this point, we may mention that the reason stars are seen earlier in the evening twilight with the assistance of tubes than without, is, as pointed out by Arago, that the tube cuts off\u2019 a large portion of the disturbing diffused light of the atmospheric strata which intervene between the star and the eye. In like manner a tube is useful even in a dark night in preventing the lateral impression of the faint light which the particles of air receive from all the other stars in the sky, and thereby increases the intensity of the luminous image and the apparent size of the star.\nDistant objects appear large to near-sighted persons, because a distinct picture is formed only at the point of intersection of the rays proceeding from an object ; as this point falls short of the retina in such persons, the retina receives the rays beyond the point of intersection, and they are consequently more extended. Myopes also read with more ease in partial darkness than those whose sight is perfect. The quantity of rays from an object is always in an inverse ratio to the square of the distance ; and as these persons naturally bring the object close to the eye, they receive the full benefit of all the light proceeding from it ; whereas other persons are obliged under similar circumstances to close the lids and contract the pupils to see distinctly, whereby much less light enters their eyes than those of myopic individuals ; hence they see with greater effort and less distinctness.\nIn congenital myopia the pupils are frequently large, and do not contract fully. To compensate for this the persons acquire the habit of knitting the brows and half closing the lids, which gives them a characteristic appearance. rlhe handwriting of near-sighted persons is generally small and cramped, the proximity of the letters to the eyes increasng the visual angle subtended by them, thus increasing their apparent size.\nAmong the exciting causes of acquired myopia are, overwork of the eyes at the focus for near objects, the indiscreet use of glasses, and the necessity of working in obscure light. The first and last may be classed together, and apply especially to engravers, watchmakers, jewellers, and other artificers, the nature of whose work requires close inspection. But there is yet another class especially subject to this' impairment of vision, namely, literary men. The public are little aware of the extent to which the studious and those who live by the exercise of their intellect, suffer from imperfection of sight. Many instances have fallen under our notice of poor students and writers, whose poverty compelled them to pursue their literary avocations in the gloom of dusky apartments, or by the aid of a dim candle, and who have become myopic and amblyopic in consequence. And scarcely less numerous are those who are visited with this affliction though pursuing their labours under more favourable circumstances. It would appear that even the study of ophthalmic science may cause the same penalty to be paid; for M. Desmarres informs us that one of his pupils became very myopic by exerting his eyes too much in the diagnosis of diseases of the eye; a sad result of most rare industry.\nA common cause of myopia is the improper use of eye glasses. In this country they are often worn from affectation ; but in France glasses are used by the young men who wish to escape the conscription, for the deliberate purpose of rendering themselves near-sighted, that constituting a ground for exemption During the years 1831, 1832, and 1833, 7'.3 per 1000 of the conscripts examined in","page":1463},{"file":"p1464.txt","language":"en","ocr_en":"146-4\nVISION.\nFrance were rejected on the score of short sight.\nOculo-cerebral congestion may give rise to myopia ; a case alluded to by Smith was probably of this nature, \u2014 that of a person who suddenly became myopic on coming out of a cold bath. And Reviell\u00ea-Parise mentions an officer who was similarly attacked at the end of a troublesome ague. Local congestion is said to produce the same effect. Desraarres relates a remarkable instance of a lady excessively presbyopic, who became nearsighted during a severe attack of conjunctivitis, the former condition of vision returning after the attach had subsided. Mr. Tyrrell also mentions a lady who had long suffered from granular lids, which were eventually cured, but she afterwards required the aid of concave glasses, from the cornea having become unusually convex during the continuance of the chronic disease. In each of these cases, there may have been some change, either in the quantity or quality of the aqueous humour, or in the consistence of the cornea.\nItis very common to meet with eyes differing in their focal length, and in such cases one usually falls into disuse ; it is also occasionally found that one eye will be myopic and the other presbyopic, a condition of vision embarrassing to the patient and the surgeon ; but the nature of which may easily be ascertained by careful trial with glasses. D-. Serre, in a memoir on the application of phosphenes, or the luminous spectra excited by compression of the eye *, states that these assist in the diagnosis of myopia. He says that in such cases the nasal and orbital phosphenes appear equal to the tempora\u2019 in constancy, brilliancy, and sometimes in size ; but he cautions us against concluding that the retinae of myopes are more sensitive than those of persons having normal vision, ascribing the above appearances to the greater prominence of the eyes, which facilitates compression, and admits of its application to the deeper parts of the eye. These results he adds, are at complete variance with the opinion of M. Stceber of Strasburg, who thinks that the proximal cause of myopia may sometimes be a peculiar alteration of the retina admitting of a complication of myopia with amblyopia, or commencing amaurosis ; for that if the retina be essentially affected, the orbital, and sometimes the nasal phosphenes are scarcely appreciable, or they may be entirely wanting. Dr. Serre further asserts that which is certainly contrary to received opinions, and (we may add), to our own experience, that when the foci of two myopic eyes differ, the retina of the eye with the shortest focus being that least used, is absolutely stronger and more active than the retina of the other eye.\nMyopia may be symptomatic of hydro-phthalmia, and of conical cornea. In the former case it will be accompanied with enlargement, and symptoms indicating some inflammation of the eye. In the latter, the change of form\n* Annales d\u2019Oculistique, tom. xxiv. p. 161.\nin the cornea will be apparent on close examination.* Instances have also come under our notice of congenital cataract having been 'mistaken for myopia, f In such cases the patients have dull vision, and are unable to see small objects distinctly even with the aid of glasses. On careful examination a greyish hue may be detected in the pupils ; and if these be dilated by atropine, the nature of the case is at once displayed by the semi-opaque or slightly turbid lenses becoming visible.\nThe progress of myopia depends very much upon the line of conduct pursued by the individual. If that be judicious from the commencement, the defect may not increase, or if acquired, may diminish ; but its march is too often as follows : \u2014 A person who is occupied for months together in reading small type (for example), finds that he discerns distant objects less and less distinctly, and at once jumps to the conclusion that spectacles are required ; he goes to an optician, tries a pair, secs better, purchases them, and proceeds with his labour. After a time he finds that these glasses do not afford the same amount of assistance they did at first ; they are carefully wiped, but still are not satisfactory, and therefore a pair of a higher power are purchased ; with these he sees sharply at first, though they do diminish a little ; but they in time are laid aside, and the individual goes on and on, until the whole scale has been run through, and he is half blinded for the remainder of his life. In the progress of such a case other symptoms often develop themselves i not only is the sight rapidly shortened, but it is weakened ; the eyes ache, and are speedily fatigued by application ; there is oppression about the brow, and often headach; he is teased with musc\u00e6 vo\u00fbtantes, and the sight is obscured from time to time by a mist.\nThe case now assumes the character of impaired vision from overwork, and unless judicious treatment be adopted, amaurosis may be the result.\nIt is important to know that near sight may be acquired in childhood by the common practice that children have, of approaching their eyes very close to any object on which their attention may be engaged. When learning to read or write, or draw, they almost invariably hold their faces sideways, nearly touching the slate or paper. This should at all times be discouraged. In like manner infants should not have very small toys given them, or such as require to be looked at closely, for not only may they be rendered short-sighted, but strabismus may be caused, for as the visual axes naturally converge when objects are held very near the eyes, the frequent repetition of this may occasion a squint. For the same reason there is sound judgment in printing children\u2019s books in good bold type, and it is w'ell to encourage young people to observe distant objects, and to describe what they\n* SeePracticafRemarlvS on Near Sight, pp. 47. 50,\nf London Journal of Medicine, vol. i. p. 507.","page":1464},{"file":"p1465.txt","language":"en","ocr_en":"VISION.\t1465\nsee in trees, landscapes, the exterior of houses, &c. As a general rule glasses are not admissible for young persons, for if worn there is scarcely any hope i f amendment ; but it is sometimes necessary to allow them during music lessons, in which case they should be of the lowest power that enables the child to see the notes, and their use should be restricted to that pursuit.\nMyopic persons, generally, should remove objects they are regarding as far from them as possible, and should avoid small type, minute writing, and microscopical investigations. The use of a high desk is very important, not merely as tending to prevent oculo-cerebral congestion, but also pain in the chest, which is often caused by stooping ; and as a general rule, all near-sighted persons, of whatever age, should exercise the eyes, when in the open air, by endeavouring to make out distant objects.\nThere is a simple plan which persons who write or read much should adopt as being highly serviceable in preserving the powers of their vision. It is that of raising their eyes from their work at short intervals, and fixing them upon the cornice of the ceiling at the further end of the room, and if there be a pattern, making it out. This exercises the eyes at the focus for distant objects; and, simple as it is, is of great use in preventing nearsight.\nThere is a form o; myopia of which we have seen several examples, and which is deserving of attention. It occurs in young persons, and leads to unmerited punishment. The youth does not hold his book so near the eyes as to attract attention, and reads fluently at perhaps eight or ten inches ; but he cannot see objectu distinctly at twenty feet. Such young persons have been brought to us under the impression that they were \u201c shamming;\u201d but careful investigation convinced us that such was not the case. Great responsibility attaches to the advice given in a case of this description, as on it depends much of the comfort of the individual during life. He should by no means be allowed glasses, as they would most assuredly confirm the mischief. His books should be of large type ; he should frequently rest his eyes when studying ; should be much in the open air ; and the eyes should be often bathed with cold spring water.\nPresbyopia (ttp\u00e9<r\u00a7vs, old ; the eye) is that condition of vision in which objects are not distinctly perceived unless they are at some distance from the eye. Although not necessarily confined to advanced years, it |s one of the changes which warn the individual that the prime of life is past, as it usually commences about the age of forty.\nTo a person in whom presbyopia is commencing, distant objects appear as clear and sharply defined as ever ; but reading, writing, and working, especially by candlelight, become irksome and distressing. The eyes feel strained, and there is uneasiness over the brow sometimes amounting to headach ; the\npage of a book appears misty, the type confused at the ordinary reading distance, and a strong light is indispensable. The person therefore draws the candle to him, and holds the book close to it nearly at arm\u2019s length, throwing his head back to increase the distance.\nThese symptoms are the result of changes in the eve which cause the converging rays of light to be brought to a focus beyond the retina, upon which a confused and imperfect image is consequently depicted. They may be the result either of flattening of the cornea or the crystalline lens, diminution in the density of the humors, or diminished curvature of the retina. Absence of the crystalline lens produces the same effect in an extreme degree.\nThe explanation of the feelings of discomfort, and other presbyopic symptoms, is simply this\u2014the object being removed to a greater distance than is natural, the visual angle is reduced in size, the picture on the retina diminished, and the quantity of light becomes less : hence the retina, with its somewhat impaired sensibility is unable to appreciate the object without effort, and a considerable increase of light.\nThe necessity for this increased quantity of light is a frequent cause of amblyopia supervening upon presbyopia, for a very large number of work-people pursue their avocations in densely crowded and ill lighted rooms, and they are obliged to struggle on despite of their failing sight. Dr. Sichel states that one of the causes which renders amblyopia in connection with presbyopia so common in the conciergeries of Paris is, that the majority of persons are tailors and shoemakers, who almost without exception inhabit confined rooms called loges> into which light and air can scarcely penetrate. Presbyopia may be congenital, and it is frequently excited in persons under thirty, by the injurious habit of wearing convex glasses,miscalled \u201cpreservers.\u201d Among the lower and even the middle classes the belief is general that if from any cause the sight is weakened, such glasses are beneficial, an impression most fallacious. It however answers the purpose of some advertising opticians to encourage the idea, regardless of the consequences to their victims.\nM. Desmarres states* that country people are almost all attacked with presbyopia at an early age, because their sight is much exercised on distant objects, and very little on near objects, whereas the dwellers in towns are attacked later in life. It may be so in France, but is certainly not the case in England. The same writer affirms that this imperfection in sight is rife in countries where the light is very bright.\nThe first indications of presbyopia are always perceived in the evening, and it is important that they should be distinctly borne in mind. During the day, persons past the meridian of life, accustomed to lead, write, or work can do so without inconvenience, but as\n* Trait\u00e9 des Maladies des Yeux, p. 809.","page":1465},{"file":"p1466.txt","language":"en","ocr_en":"1466\tVISION.\nthe shades of evening draw in and lights are introduced, they find that they cannot fix their eyes upon their work as before, without fatigue ; if they persist, this fatigue increases, and after a time amounts to headach ; but if they put on convex glasses of a low power, all discomfort vanishes, and their sight is at once restored, and they can pursue their occupations with perfect ease. If however they persist in abstaining from glasses, and by increasing the light endeavour to improve their sight, the retina will be over stimulated, and in addition to presbyopia, they will acquire dull and imperfect vision of all objects, far as well as near.\nThere are persons whose sight, never particularly good, but who from easy circumstances have used it little, become alarmed at finding, about the age of fifty, that their eyes appear to have suddenly failed, and they think they are becoming blind. Many such cases have fallen under our observation. The facts are simply these : presbyopia has advanced so slowly and gently, and the eyes have been used so little, that until the defect has become confirmed, the parties are unconscious of its existence. Some accidental circumstance, as an attempt to read a newspaper in the evening, reveals the imperfection : proper glasses are alone required to restore the vision.\nBelladonna and atropine produce temporary presbyopia by suspending the power of adjustment, the eye being fixed at the focus for distant, objects. Mydriasis also renders the individual more or less presbyopic. Presbyopia may be converted into myopia, and vice versa, of which cases are related by various writers.*\nDr. Sichel has justly pointed out that neuralgia of the eye-ball is by no means infrequent in connection with presbyopia. We have seen several instances, and generally traced it to overstraining the eyes in efforts to read or work without glasses. The pain is at first transient, but if the exciting cause be continued, it becomes more severe and persistent, extending from the eye to the neighbouring parts and not readily yielding to treatment. In such a case, rest to the eyes is all important in the first instance, and suitable glasses are indispensable.\nThe chief remedial measures for presbyopia are comprised in the early and judicious use of suitable glasses, but the means of prolonging natural sight and of staying the progress of presbyopia are as follows : \u2014 Persons habitually engaged in minute work should ascertain by experiment the greatest distance at which they can clearly and without effort see their work, and always endeavour to maintain that distance ; they should raise their eyes from time to time, and direct them to some object at the opposite end of the room to alter the focus: but when engaged in lighter pursuits they may if agree-\n* See Practical Remarks on Near Sight, &c. pp. 90\u201495.\nable read at less than their working distance. In reading or writing just that amount and quality of light is proper which thoroughly illuminates the object, and yet feels grateful and pleasant to the eyes. It is injurious to face the light ; the best position when reading is with the light rather behind and on one side; the eyes are thus protected from all heat and glare, while the object is fully illuminated. When this arrangement is inconvenient, a screen or shade may be used with advantage. Reading by twilight and firelight is highly injurious to feeble eyes. Stooping over work should be avoided as one great cause of congestion of the eyes ; for which reason a high desk is useful. Whenever the e^es feel fatigued,-\u00ab few minutes\u2019 rest and bathing with cold water will be refreshing and beneficial. There are two descriptions of lenses jin common use for spectacles, the double concave for short sight, the double convex for long or aged sight ; plano-convexes and piano-concaves are scarcely ever employed. It sometimes happens however that the curvatures of the surfaces are unequal; for instance, a ten-inch lens may be required, but the optician may not have what is technically called the \u201ctool\u201d of the proper curve, and therefore selects two tools, the numbers of which combined make ten\u2014as one of seven and the other of three inches\u2014and the lens produced by these, though with surfaces of very unequal curvature, answers the purpose perfectly. Periscopic glasses were invented by Dr. Wollaston, but are seldom employed, and there are others with attractive names but not deserving of particular notice.\nA common prejudice exists in favour of pebbles, but it is erroneous, for whilst on the one hand their chief merit consists in extreme hardness so that they are not easily scratched, that very hardness renders them difficult to cut and grind, many being broken in the process. They are expensive from this circumstance, and the difficulty of meeting with crystal of sufficent size which is pure and without flaw. Crown glass is now made of such excellent quality and so colourless that lenses made, from it possess every qualification that can be desired. Among the many singular things characteristic of the Chinese is their spectacles. Without knowing anything of the theory of the convergence and divergence of light by means of lenses, both convex and concave lenses are used all over the empire, and of such a singular size and shape that there' can be little doubt of their being original inventions. They are made of rock crystal ground with the powder of corundum and are of immense size, being retained in their position on the face by means of silken cords with weights attached, which are slung over the ears.\nFrames, of whatever material they may be formed (and blue or bronze steel is the best), should possess the following qualifications. The rims should accurately fit the form of the lenses, and be sufficiently slrong to retain them ; the connecting arch or bridge","page":1466},{"file":"p1467.txt","language":"en","ocr_en":"VISION.\n1467\nmust be of such width and shape that it will fit the nose accurately, and maintain the centre of each glass in front of the axis of the corresponding eye. This is a point of great importance, otherwise the eyes will not have the full \u2018assistance of the lenses. The necessity for the bridge being adapted correctly was proved by a case that recently came under our notice, where* a wart on the side of the nose had degenerated into a scirrhous growth from the friction of an ill fitting spectacle frame which constantly pressed upon, and irritated that point. The lateral branches of the frame should be sufficiently strong and elastic to retain it in its place, firmly and immoveably under all movements of the head ; and they should be of such a shape and size that no undue pressure can be caused on the temples or sides of the head. Besides the injury to the eyes from ill-fitting frames, persons acquire the habit of grimacing in their efforts to see through them. Hand glasses and those retained on the nose by a spring are objectionable ; the latter, when clipping the nose, almost invariably throw the centres of the glasses out of the axial lines of the eyes, and both are deficient in that steadiness which is indispensable to perfect and comfortable vision.\nThe power of bi-convex glasses is indicated by their numbers, and these numbers signify the inches of the focal length.\nThe numbering of the French glasses, whether presbyopic or myopic, has a much more extensive range than the British, as will be seen by the following lists.\nPresbyopic (French'). 80, 72, 60, 48, 36, 30, 24, 20, 18, 72, 60, 48, 36, 30, 24, 20, 18, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4a, 4, 3b 3,2b 2, If, If, 1.\nMyopic {French). 60, 30, 20, 18, 16, 15, 14,\n13,\t12, 11, 10, 9, 8, 7, 6, 5, 4f, 4, 3f, 3f, 3,\n9391 9 13 ii\t]\n~4> ^25 \u00a31 *4> *2* J -55 t*\nPresbyopic (British). 48, 36, 30, 24, 20, 18,\n14,\t12, 10, 9, 8, 7, 6, 5b 5, 4f, 4, 3|, 2f, 2f, 2f, 2-jfj-, 2, If, If.\nMyopic (British). 00, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20.\nThe numbers of the double convex glasses below 5 in both scales are confined to patients who have undergone the operation for cataract-\nThe golden rule in the selection of spectacles, whether for myopia or presbyopia, is to choose the lowest power that is productive of distinct vision ; and so long as these afford the necessary assistance the party should rest contented, for if he begins with too high a number or rashly increases the power, it will be found not only difficult to go back, but equally so to subdue the inclination for further increase.\nA myopic person should therefore select glasses which will enable him to distinguish the outlines of objects distinctly at about forty-five feet, without diminishing them in the slightest degree ; and with these he should be satisfied, not changing them for a higher power unless absolutely obliged.\nIt frequently happens that the eyes of\nmyopic persons are of different focal length, in which case great care should be taken by diligent trial to determine the powers which will bring the eyes to perfect equality, and with these lenses the frames should be fitted ; but there is another condition of vision which is sometimes embarrassing ; it is when one eye is myopic and the other presbyopic. This can only be ascertained by careful trial of each eye with convex and concave lenses, and the results are sometimes quite unexpected ; if therefore a person using glasses complains of faulty vision with one eye, which cannot be satisfactory accounted for, it is proper to try the eye with a different description of lens, which will frequently show the nature of the case at once. Eyes thus faulty require a double convex and a double concave lens fitted into the same frame, and the same rules apply to their selection, as to glasses generally.\nIn England the lowest power in use for presbyopia is a glass of 48 inch focus; in France it is otherwise, as will be seen by reference to the table already given. M. Sichel commences with a 72 inch, and in some cases with a 96 inch ; Mr. A. Ross, however, who has had an immense amount of experience as an optician, informs us that he has met with but one person who could perceive any sensible difference between these two powers, as far as assistance to the sight was concerned. It is quite possible that in the early stage of presbyopia a 72 inch glass may be sufficient, and if found to be so, it should by all means be preferred to a higher, number ; but, practically speaking, a 48 inch is that most usually required, because persons in this country seldom seek assistance until the presbyopia has advanced beyond the aid of a 72 inch glass. It has been recommended to calculate the requirements of the eye by the age of the individual, but this is fallacious, as eves differ much in their natural powers of vision, and not less in the amount of assistance they need. The only true mode of obtaining suitable spectacles is by absolute trial.\nPersons should not be satisfied with a hasty trial of glasses in an optician\u2019s shop, for the eyes soon become excited and confused, rendering it impossible to arrive at a correct decision. It is far better to select two or three pairs of spectacles which are near the mark, and to test them leisurely at home. Those to be selected should simply give blackness and distinctness to the letters of a book, and enable a person to read or work at the natural distance with perfect comfort ; such glasses supply to the eyes precisely that amount of refractive power in which they are deficient.\nCylindrical Eye. \u2014 This peculiarity of the organ of vision was first investigated and explained by the present Astronomer Royal. It depends on the curvature of the cornea being greater in the vertical plane than the horizontal, whereby the rays are refracted to a nearer focus in a vertical than in a horizontal plane ; this gives rise to much confusion of","page":1467},{"file":"p1468.txt","language":"en","ocr_en":"14-68\nVISION.\nvision, a point appearing a line, a circle an oval, and a square a parallelogram. In an interesting case related by Dr. Robert Hamilton*, the patient, when looking at a clock, was unable to distinguish the hands if they pointed perpendicularly, as at six o\u2019clock, but if horizontally he had no difficulty : so when looking at a wheel at a little distance, the horizontal spokes only could be seen. The patient was a coach painter by trade, and this peculiarity of vision greatly interfered with his business, for he could not draw vertical lines with any degree of correctness, and unwittingly made them slanting, a serious fault in heraldic devices ; horizontal lines he drew with perfect precision. His method of correcting the perceptions of perpendicular lines was to bend his head at right angles with his body, whereupon upright bodies became distinct and accurately represented. This man also practised a manoeuvre which forcibly reminds us of an act common to persons having conical corneae, that of placing the fore-finger at the outer angle of the eyelids and drawing them outwards whereby vision is improved.\nTo remedy the defect under which he laboured, Professor Airey made a pin-hole in a blackened card, which he caused to slide on a graduated scale ; then strongly illuminating a sheet of paper and holding the card between it and the eye, he had a lucid point on which he could make observations with ease and exactness. Then resting the end of the scale on the cheek bone he found that the point at the distance of 6 inches appeared a very well-defined line inclined to the vertical about 35\u00b0 and subtending an angle of 2\u00b0. Again, at the distance of 3^ inches, it appeared a well-defined line at right, angles with the former, and of the same apparent length. It was therefore necessary to make a lens which, when the parallel rays were incident, should cause them to diverge in one plane from the distance of 3i and in the other plane from the distance of 6 inches. The professor obtained a lens of which the radius of the spherical surface was 3\u00a3 inches, of the cylindrical 4\u00a3 inches, and with this he was able to read the smallest print.\nIn Dr. Hamilton\u2019s patient the relation of the horizontal to the vertical focus appeared to be as inches to 6| inches, and on trying him with- plano-concave cylindrical lenses, it was found that a lens of 24 inches focal length, the cylindrical surface being made to act horizontally, operated very beneficially. Besides this irregular refraction the man was myopic, but the lenses in question fitted as spectacles, enabled him to see weil.\nThe defect of the cylindrical eye may be detected by making a small pinhole in a card which is to be moved from close to the eye to arm\u2019s length, the eye meanwhile being directed to the sky, or any bright object of sufficient size. With ordinary eyes the indistinct image of the hole remains circular at all distances, but to an eye having this peculiar defect it becomes elongated, and when the card is at a\n* Monthly Journal of Medical Science, June 1847.\ncertain distance passes into a straight line. On further removing the card the image becomes elongated in the perpendicular direction, and finally if the eye be not too long-sighted, passes into a straight line perpendicular to the former.\nProfessor Stokes has invented a highly ingenious instrument for determining the nature of the required lens, and the following is the proposition on which it is based.\nConceive a lens ground with two cylindrical surfaces of equal radius, one concave and the other convex, with their axes crossed at right angles ; call such a lens an astigmatic lens : let the reciprocal of its focal length in one of the principal planes be called its power, and a line parallel to the axis of the convex surface its astigmatic axis. Then if two thin astigmatic lenses be combined with their axes inclined at any angle, they will be equivalent to a third astigmatic lens determined by the following construction.\nFrom any point draw two straight lines representing in magnitude the powers of the respective lenses, and inclined to a fixed line drawn arbitrarily in a direction perpendicular to the axis of vision at angles equal to twice the inclinations of their astigmatic axes, and complete the parallelogram. Then the two lenses will be equivalent to a single astigmatic lens represented by the diagonal of the parallelogram in the same way in which the single lenses are represented by the sides. A piano-cylindrical or spherico-cylindrical lens is equivalent to a common lens, the power of which is equal to the semi-sum of the reciprocals of the focal lengths in the two principal planes, combined with an astigmatic lens, the power of which is equal to their semi - difference. If two piano-cylindrical lenses of equal radius, one concave and the other convex, be fixed one in the lid and the other in the body of a small round wooden box, with a hole in the top and bottom, so as to be as nearly as possible in contact, the lenses will neutralise each other when the axes of the surfaces are parallel ; and by merely turning the lid round, an astigmatic lens may be formed of a power varying continuously from zero to twice the astigmatic power of either lens. When a person who has the defect in question has turned the lid till the power suits his eye, an extremely simple numerical calculation, the data of which are furnished by the chord of double the angle through which the lid has been turned, enables him to calculate the curvature of the cylindrical surface of a lens for a pair of spectacles which will correct the defect in his eye.*\nA curious case is related in the Annales d\u2019Oculistiquef, of an anomaly of vision, which was probably the consequence of a defect in the form of the cornea, such as that under consideration. M. Schnyder, the Pastor of Menzberg in the Canton of Lucerne,\n* Eeport of the British Association, vol. xviii,\nf Tom. xxi. p. 222.","page":1468},{"file":"p1469.txt","language":"en","ocr_en":"VITAL STATISTICS.\n1469\nwas presbyopic for horizontal lines and myopic for vertical. This he remedied by wearing spectacles the glasses of which were cylindric bi-convexes, with rectilinear, horizontal and similar axes. These glasses obviated the presbyopia relative to the horizontal lines, and they were combined with sphero-biconcave lenses to get rid of the myopia for vertical lines. Each of the glasses was made moveable for facility of cleaning.\nThe following means are recommended to ascertain if an eye has the defect now described. The person should attentively contemplate for some time and with attention a cross, three or four lines in size, made of fine wire and fixed in a frame. If affected, he will see the horizontal lines differ in thickness and blackness of tint from the vertical.\nTo determine the focal length which the lenses should have, a person whose sight is presbyopic in one direction should take bi-sphero-convex lenses which enable him to see distinctly at the ordinary distance the lines which otherwise appear indistinct: he can deduce the focal distance of the cylindrico-convex glasses. A person myopic in one direction should do the same with regard to bi-sphero-concave lenses. The convex glasses should be chosen of one or two numbers stronger.\nBibliography. \u2014Baptista Porta, Magi\u00e6 Natural is lib. iv., Antverpi\u00e6, 1560. Fabriciusab Aqua-pendente, De Visione. Venetiis, 1600. Aquilonius, Opticorum, libri iv., Antverpi\u00e6, 1613. Schemer, Oculus, \u00c6niponti, 1619. De la Hire, M\u00e9moires de Math\u00e9matique, &e. Paris, 1694. Gregorius, Optica Promota, seu Radiorum Mysteria enucleata. Ma-seres, Script. Optici. Barrow, J., Lectiones XVIII. in quibus Opticorum Ph\u00e6nomenon Eationes ex-ponuntur. Maseres, Script. Optici. Berkeley, A N ew Theory of Vision, Dublin, 1709. Mariotte, \u0152uvres, Leide, 1717. Pemberton, De Faeultate Oculi. Haller, Disp. Anat. vol. vii. 1719. Jurin, An Essay on Distinct and Indistinct Vision, Smith\u2019s Compleat System of Opticks, vol. ii. 1738. Porterfield, W M.D., A Treatise on the Eye, 8vo., Edin., 1759. Fontana, Dei Moti dell\u2019Iride, Lucca, 1765. Priestley, J., The History and Present State of Discoveries relating to Vision, Light, and Colours, quarto, London, 1772. Harris, A Treatise of Optics. London, 1775. Olbers, De Internis Oculi Mutationibus, Gott. 1780. Blumenbach, De Oculis Leuc\u00e6thiopum et Iridis Motu, 1786. Mashelyne, Phil. Trans. 1789. Hossack, Phil. Trans. 1794. Ramsden, Phil. Trans. 1795. Du Tour, M\u00e9m. de Math\u00e9matique et de Physique, t. iii. and iv. Dalton J., Extraordinary Pacts relating to the Vision of Colours. Memoirs of the Literary and Philosophical Society of Manchester, vol. v. pt. i. 1798. Chenevix, Phil. Trans. 1803. Young, 71, Lectures on Natural Philosophy, London, 1807, and in Philosophical Transactions. Gerson, De Forma Corne\u00e6, Gott. 1810. Horn, On the Seat of Vision, 1813. Wells, Essay on Single Vision with Two Eyes, London, 1818. Chossat, Annales de Chimie, Paris, 1819. Gillies, J., Account of a Peculiar Modification of Vision, Edin. Phil. Journal, vol. ii. 18-20. Home, Sir E., Phil. Trans. 1822. Maseres, F., Scriptores Optici, London, 1823. Descartes, \u0152uvres, Paris, 1824-26. Kitchener, W., The (Economy of the Eye, 1824. Simonoff, Majendie, Journal de Physiologie, tom. iv., Paris, 1824. Mile, Journ. de Physiol., tom. vi. Chantilly, G. de, Th\u00e9orie des Couleurs et de la Vision, 80. Coddington, An Elementary Treatise on Optics, Camb. 1825. PouiUet, El\u00e9mens de Physique, Paris, 1829 Brewster, Sir D., A Treatise on Optics, London, 1831, also in Trans, of Royal Society of Edinburgh, in Philosophical Ma-\ngazine, and in Edinb. Philos. Journal. Berthold, \u00fcber das Aufrecht-erscheinen der Gesichts-objecte, 1830. Tourtual, Die Chromasie des Auges, Meck. Arch. 1830. Posas, Handbuch der Theoretischen und Practischen Augenheilkunde, Wien, 1830. Lloyd, On Light and Vision, Lond., 1831. Luchtmans, De Mutatione Axis Oculi secundum diversam Distantiam Objecti, Traj. ad Rh. 1832. Bartels, Beitrage zur Physiologie des Gesichts-Sinnes, Berlin, 1834. Volkmann, Beitr\u00e4ge zur Physiologie des Gesicht-Sinnes, Leipz. 1836. M\u00fcller, J., Elements of Physiology by Baly, and Vergleichende Physiologie des Gesichts-Sinnes, Leipz. 1826. Alison, Trans. Royal Society of Edinburgh, vol. xiii. 1836. Treviranus, Beitr\u00e4ge zur Aufkl\u00e4rung der Erschein u. Gesetze des Organisch. Lebens. Heft 1. 3. and Beitr\u00e4ge zur Anat. u. Physiol, der Sinneswerkzeuge, 1828. Webster, T., Elements of Physics, London, 1837. Wernenck, Zeitschrift f\u00fcr die Ophthalmologie, Heid., 1837. Seebeck, lieber den bei manchen Personen vorkommenden Mangel an Farbensinn. Pogg. Ann. 1837. Griffin, D., Lond. Med. Gazette, vol. xxii. 1838. Purkinje, Ammon\u2019s Monatschrift f\u00fcr Medicin, also Beobachtungen und Versuche zur Physiologie der Sinne, i. Prag., 1823. ; ii. Berl., 1825. Hueck, Die Bewegungen der Krystallinse, Dorp.,\n1839.\tHerschel, Sir J. W., article \u201c Light,\u201d Cyclo-p\u00e6dia Metropolitana. Szokalski, Essai sur les Sensations des Couleurs clans l\u2019Etat Physiologique et Pathologique de l\u2019\u0152il, Ann. d\u2019Oculistique, tom. iii.\n1840.\tMackenzie, W., M.D., The Physiology of Vision, London. 1841. Chevalier, C., Manuel des Myopes, et des Presbyopes, Paris, 1841. Earle, Pliny, M.D., On the Inability to distinguish Colours, Amer. Journal of Med. Science, vol. xxxv. Peschel, Elements of Physics, Lond. 1845. Matteuci, Lectures on the Physical Phenomena of Living Beings, by J. Pereira, 1847. Muller. J., Principles of Physics and Meteorology, Lond., 1847. Todd and Bowman, The Physiological Anatomy and Physiology of Man, Lond., 1847. Cooper, W. White, Practical Remarks on Near Sight, Aged Sight, and Impaired Vision, London, 1847. Smee, A., Vision in Health and Disease, London, 1847. Sichel, Le\u00e7ons Cliniques sur les Lunettes, Brux. 1848. Jones, T. Wharton, The Wisdom and Beneficence of the Almightjq as displayed in the Sense of Vision, London, 1851.\n(The subject of Vision is more or less treated of in works on Optics and Natural Philosophy; papers on its physiology and pathology are very numerous, and are to be found in Philosophical Transactions and Journals, in the Annales d\u2019Oculistique, &c.)\n(W. White Cooper.)\nVITAL STATISTICS.\u2014The duration of human life, with a consideration of the principal causes^ by which it may be lengthened or curtailed, is a subject which evidently belongs both to the domain of physiology and to that of statistics. It belongs to physiology, inasmuch as the duration of human life is the final effect of the operation of natural causes brought to bear on the healthy human frame ; and it belongs to statistics, whether we use that term in the less exact sense of a branch of human knowledge largely indebted to the use of numbers, or in the more accurate sense of a department of science, having an important bearing on the interests of the public.*\nIn this place it is proposed to take only a limited view of the subject of Vital Statistics, and to examine the scientific methods which have been suggested and employed for determining the true duration of human life in communities and classes of men ; in other\n* For some remarks on the true meaning of the term \u201cStatistics,\u201d see Statistics, Medical, note,","page":1469},{"file":"p1470.txt","language":"en","ocr_en":"VITAL STATISTICS.\nwords, to do for this important branch of statistics what has been done elsewhere for the statistical or numerical method.* Having already insisted on the precautions to be observed in the use of numbers as a scientific instrument, it remains to determine the precise value of those measures of the duration of life which are in common use for scientific and practical purposes.\nOn a superficial view of the subject, it might seem sufficient, in order to determine the mean age attained by a given class of persons exposed to a given class of influences, to collect the ages, at death, of a certain number of persons belonging to that class, to add those ages together, and to divide the sum bv the number of persons. But it must be evident, on further consideration, that an average so obtained may furnish a very imperfect measure of the longevity of the class, and of the force of the influences brought to bear upon the individuals of whom it is com-Posed.\nIn order to build up- a science of Vital Statistics\u2014in other words, in order to determine the true influence of external agents on the duration of human life, we must make use of such materials as happen to be ready to our hands. These materials do not always present themselves in the same shape, nor do they all possess the same value. Sometimes they are simple averages ; at other times they are complex calculations based upon the same, or similar facts, but moulded into new forms by means of certain necessary corrections. A few preliminary observations on these materials will be found to answer several useful purposes. They will serve, at one and the same time, as a test of the value of the principles sought to be established, and as a check to the tendency with which the statist is often reproached to exaggerate the value of inferences drawn from numerical data.\nSeveral methods are in use for measuring the duration of human life. Of these, the best known and most commonly employed are the following : \u2014\n1. The mean age at death ; 2. The rate of mortality; 3. The expectation of life ; 4. The mean duration of life ; and 5. The probable duration of life. Other terms, such as the specific intensity of life, and other methods, such as the ages of the living, are occasionally employed.\n1. The wean age at death. \u2014 The mean, or average age at death, is the sum of the ages at death,\u00b0divided by the number of deaths. Thus, if five persons die at the respective ages of 20, 30, 40, 50, and 60, their mean, or .\t. .\t204-30 + 40 + 50 + 60,\naverage age at death is ---------\nor 40 years ; and if a second group of five persons die at the respective ages of 20, 35, 50, 65, and 80, their mean age at death is 20+35+50+65+80 , or 50 years> NoWj if\n5\nthese two groups of five persons were each exposed during their lives to a peculiar set of\n* See Statistics, Medical, p. 801.\ninfluences, the mean age which they respectively attained would be a measure of the force of those influences. But such a measure would be open to the serious objection that the number of facts from which the averages are calculated is insufficient. Let us, however, suppose this objection to be set aside by increasing the number of deaths in each case to several hundreds or thousands, so as to embrace either the entire number of deaths of the classes submitted to comparison, or such a considerable proportion of deaths taken without selection as would give satisfactory results in accordance with the strictest requirements of the numerical method, the question still presents itself, Is the mean age at death a safe measure and standard of comparison ? The answer to this question must be in the negative. The mean age at death is not always a safe and sound standard. Its employment would often lead to very erroneous inferences. It will therefore be necessary to discriminate between those cases in which it may be employed with safety, and those in which its use would lead to fallacious results.\nThe mean age at death can be employed with safety as a true test or measure only in those cases in which the calculation purporting to embrace an entire class of persons, every member of that class is included, or in which the calculations embracing only a section of an entire class, the class in question is retained in a state of perfect uniformity during the whole time comprised in the calculation. According to the first supposition, we take a given number (say 100,000) of children born in a given year, and trace them through life till they are all dead, summing up their ages at death, and dividing by the number of deaths. According to the second supposition, we extract from some register of deaths the ages of all who die during some term of years, having ascertained, by referring to the census, that the population has continued stationary (that is to say, constantly gaining as many by fresh births as it loses by death), during the time over which the calculations extend. The same reasoning will be found to apply to the mean age at death, taken as a measure ot the true duration of life of the members of any handicraft, trade, or profession. It can only be a true measure so long as the blanks caused by death are filled by new recruits, entering at the same age as the age of entrance of the deceased. In all other cases but those now specified, the mean age at death is a more or less fallacious measure of the true duration of life.\nAs the mean age at death has been lately revived as a measure of the duration of human life, and a test of the sanitary condition of the population, though its fallaciousness was long since recognised and pointed out by the early constructors of life-tables, it may be well to devote some space to a statement of the cases in which the proposed test is most open to objection.\na. The mean age at death has been employed as a test of the sanitary condition of a nation,","page":1470},{"file":"p1471.txt","language":"en","ocr_en":"YITAL STATISTICS.\nJ 471\nand as a measure of that condition when compared with another nation, or with the same nation at another time, in ignorance or forgetfulness of the well-ascertained fact that the living population of one nation may differ very widely in its composition from the living population of another, and that the elements of the population of the same nation may undergo very extensive changes even in a short term of years.\nIn illustration of the first of these statements, it will suffice to instance the strongly-contrasted populations of England and America, of which the first has 46 and the second 54 in the hundred under 20 years of age, the number above 20 being, of course, reversed. In the two populations of Denmark and Sardinia, on the other hand, the relative proportions at different ages are very nearly the same ; and, when expressed in round numbers, for long intervals of age, identical. As a general rule, however, there is considerable difference between one population and another in the proportion of persons living at the same ages. In support of the second of these statements, the change which took place in the population of England in the interval from 1821 to 1841 may be adduced. At the former period, the persons living under 20 years of age were 49 per cent, of the whole population, but in 1841 they had fallen to 46 per cent.\nThere is no room for doubt, therefore, that different populations vary in their composition, and that the same population may, in course of time, undergo considerable changes, and exhibit very striking contrasts in the number of persons living at different ages.\nSuch being the case, it will not be difficult to prove that the differences in question do so materially affect the mean age at death as to rob it of its alleged value as a test or measure of the sanitary condition of nations. We have only to suppose the young population of America transferred to England, and exposed to the same causes of death as determine the duration of life of its own inhabitants, in order to be fully convinced of the fallaciousness of this test. Now, according to the rate of mortality prevailing in England, little more than half its inhabitants die before completing their 20th year, and somewhat less than half after that age. If the mean age of all who die under 20 years of age be taken at 5 years, and of all who die above 20 at 60 years, the mean age at death of fifty persons dying out of the respective populations of England and America, will be about 34 and 30 years. These numbers, however, though correctly calculated from the rough data just assumed, diverge much less widely than the true results, for the actual mean age at death, which is 29 years in England, is only 20 years in America.* * So that two populations, subject to the same law of mortality, and losing the same number of persons at the same ages, in\n* See an essay by F. G. P. Neison, Esq. in the 7th volume of the Journal of the Statistical Society.\nconsequence of the different constitution of their respective populations, may have a widely different mean age at death. Similar results to those obtained by comparing England and America are arrived at if we compare England in 1821 with England in 1841. The mean age at death, which in 1821 was 25 years, became in 1841, owing to the change in the population already referred to, 29 years.* If any further illustration of the fallacy of the mean age at death, when used as a test of the sanitary state of nations, were required, it might be found in its failure when applied to countries of which the true position in the sanitary scale has been ascertained by the application of unexceptionable tests. The three nations, England, France, and Sweden, for example, occupy the following relative position :\u2014\n1. England. 2. France. 3. Sweden.\nBut if the mean age at death were taken as our guide, they vrould rank as follows :\u2014\n1. France. 2. Sweden. 3. England.\nThe mean age at death being 34 for France, 31 for Sweden, and only 29 for England, t b. The mean age at death has been employed as a measure of the relative sanitary condition of English counties, cities, and towns, of town and country, and of the several districts of large cities. To show the fallacy of the method as so applied, it will suffice to prove that the populations thus compared are composed of different elements. Taking, as before, the number living below 20 years of age as an illustration, it appears that while there are 47 in the hundred under 20 in Essex and Suffolk, there are only 44 in the hundred under 20 in Staffordshire ; that for 47 in the hundred in Leeds, 46 in Sheffield and Birmingham, and 44 in Manchester, there are only 42 in Liverpool, 41 in Exeter, and 40 in London ; and, lastly, that the population under 20 years of age, which amounts to 47 per cent, in Bethnal Green falls as low as 41 in Clerkenwell, 40 in Kensington, 36 in St. Gdes\u2019s and Marylebone, and 31 in St. George\u2019s, Hanover Square. The effect of this variable distribution of the population on the mean age at death is very well marked, and is placed in a very striking light by supposing the population of the metropolis to be transferred to some of these counties and cities, and to be exposed to the influences for good or evil which are brought to bear on the duration of life of their actual populations. Thus, if the population of London, of which 40 per cent, are under 20 years of age, were to be transferred to the county of Hereford,\nThe exact age, deduced from the rough data assumed in the text, will be as follows : \u2014\nEngland, ~ x 5 +S*x60=115+1620=1735, which, di-\nvided by 50, gives 347 as the average age. America, ^x5 +^X60 =135+1380=1515,\nwhich,\ndi-\nvided by 50, gives 30\u20183 as the average age.\n* For the facts on which these comparisons are founded, see an essay in the 6th vol. of the Journal of the Statistical Society. By G. R. Porter, Esq.\nt See the 6th annual Report of the Registrar General, p. 572.","page":1471},{"file":"p1472.txt","language":"en","ocr_en":"VITAL STATISTICS.\nwhere the average age at death is nearly 38\u00a3 years, the mean age at death would become 30^ years, or a year and a half in excess of the mean age at death of the existing inhabitants of London. The advantage, therefore, which the county of Hereford enjoys oyer the metropolis, in a sanitary point of view, instead of being represented by the difference between 381 and \u201829 years, or 9\u00a3 years, is really not more than a year and a half. Again, the average age at death in the metropolis is 29 years, and in Sheffield 23 years ; but if the population of the metropolis were transferred to Sheffield, the average age at death would be 28 years. So that the difference of 6 years, which, according to this test of the mean* age at death, marks the sanitary superiority of London over Sheffield, dwindles, under this very obvious correction, to one year. If we apply the same correction to the several districts of the metropolis, we obtain similar results. Bethnal Green is the district in which the mean age at death is lowest, while in Kensington it attains its maximum. In Bethnal Green the mean age at death is 26, in Kensington 32. But the population of Bethnal Green transferred to Kensington, would have a mean age at death of 27 years ; so that in this case also a difference of six vears in favour of the more aristocratic quarter dwindles down to one year. In some cases the use of this corrective actually reverses the position of the two populations submitted to comparison. Thus, the mean a^e at death in the united parishes of St. Giles\u2019s and St. George\u2019s Bloomsbury is 28 vears, and in Bethnal Green, as has just been stated, 26 ; but transfer the population of Bethnal Green to St. Giles\u2019s, and the mean age at death becomes 24 years. The application, therefore, of this correction completely alters the relative position of the two parishes, so that the parish which, when tested by the mean aire at death, seemed the healthiest, proves to be the most unhealthy. Serious errors and exaggerations have also been committed in comparing the smaller districts of our large towns with each other. The meanest and most squalid districts are as naturally the resort of those who marry early, and of those who are sunk into poverty by the burden of large families of young children, as better districts are the abodes of the more prudent and least encumbered members of society. The lowest districts of the large towns of England are also the resort of that part of ournopulation which indulges most habitually in intemperance, and in all the habits that engender poverty, misery, and disease. It is, therefore, inevitable that in comparing the worst districts with those of a somewhat better class, we should be comparing populations containing a large proportion of persons liable to a high mortality tor reasons other than the insalubrity of the districts themselves with those containing a smaller proportion.\nc. The mean age at death has also been used to test the sanitary condition of different classes of persons inhabiting the same town\nor town district. A very extensive series of tables, for instance, has been compiled, in which the mean age at death of the gentry, tradesmen, artisans, and paupers of the several parishes of the metropolis is represented, and used as a measure of their sanitary condition.* The parish of St. James\u2019s, Westminster, in which the class termed gentry is more likely to be appropriately named than in the poorer and less fashionable parishes, may be conveniently taken as an example. In tins parish the average age at death, children included, is 42 for gentry, 26 for tradesmen, 21 for artisans, &c., and 49 for paupers. The differences are here so extraordinary, as only to admit of explanation on the supposition of a vast disproportion between the numbers living at the same ages in the several classes. If the element of age in the living is disregarded in comparing the gentry with the artisans out of the workhouse, it must equally be disregarded in contrasting the gentry with the paupers in the workhouse, who are drawn chiefly from the artisan class. The difference between 49 (the mean age at death of paupers), and 42 (the mean age at death of the gentry) is obviously due to the greater average age of the inmates of the workhouse, as the difference between 42 (the mean age at death of the gentry), and 21 (the mean age at death of artisans), is traceable mainly, if not wholly, to the great disparity in the ages of the living members of the two classes. Unfortunately we are not yet in a condition to apply to the mean age at death of these classes of the population, the same correction which, when applied to counties, cities, and city districts, served in so striking a manner to equalize the results. The ages of the living members of the several classes of society is still an important desideratum. The tables under consideration also give the mean age at death of gentry, tradesmen, artisans, and paupers dying after 21 years of age. In the parish of St. James\u2019s, Westminster, the mean ages at death of these classes are 57, 51, 46, and 58 respectively. The differences, though less considerable, are still at total variance with the results of the most accurate inquiries into the value of life of the same classes of society f, and only admit of explanation by supposing a great disparity in the ages of their living members, together with an erroneous method of selection and classification.\nd. The mean age at death has also been employed to test the sanitary state of different\n* These Tables are published in the same volume (vol. vii.) of the Journal of the Statistical Society, which contains Mr. Neison\u2019s valuable essay just quoted. They form part of a paper by Mr. Chadwick, \u201cOn the best Modes of representing accurately by Statistical Returns the Duration of Life, and the Pressure and Progress of the Causes of Mortality among different Classes of the Community, and amongst the Populations of different Districts and Countries.\u201d\nf See especially, Contributions to Vital Statistics, by F. G. P. Neison, in which the artisan class is shown to occupy a much more favourable position in the sanitary scale, than had previously been supposed.","page":1472},{"file":"p1473.txt","language":"en","ocr_en":"14-73\nVITAL STATISTICS.\nclasses of society, and of the members of different professions, without reference to their place of residence. But little objection can be made to this test when applied with ordinary precaution. If the earliest age admitted into the tabular abstracts, from which the averages are calculated, is the same in all the classes submitted to comparison ; if during the time over which the observations extend the classes compared with each other have received no rapid accession of numbers ; and if the deaths are those of the whole body of the profession or trade (or, if of a section only, then of a similar section in every case), the mean age at death will constitute a fair measure of the relative sanitary condition of the several classes in question. But if, on the other hand, two professions or occupations are compared, in which the age at entry is not the same; or the one is stationary in point of numbers, while the other is rapidly increasing ; or if the whole body is taken in the one case, and only the senior or junior members in the other, the results will be quite unworthy of confidence.\nSome of the greatest misapprehensions existing with respect to the duration of life of certain classes of the community, are traceable to the selection of the senior members of a class to represent the entire class to which they bcdong. Nothing is more common, for instance, than to hear royal families, or the members of the aristocracy, or the clergy, or the army, spoken of as long-lived, on the strength of the advanced ages attained by kings, peers, archbishops, or general officers. In making a selection of the more conspicuous members of the class, the significant fact is overlooked that they are also the oldest members, and that they do not attain their exalted rank till a period of life greatly in advance of that at which they entered their several professions. The mean age, at death, for example, of archbishops and bishops of the established church, is upwards of 71 years, but the mean age at death of the whole body of the clergy is about 64 years. A similar disparity would be found to exist between the peers and the whole body of the aristocracy, and between general officers in the army, and admirals in the navy, and the whole body of officers in the two branches of the public service.\nThe tables already referred to as comparing the, four classes of gentry, tradesmen, artisans, and paupers in the several districts of the metropolis, supply analogous examples of erroneous selection and classification. In the great majority of the metropolitan parishes, for instance, there is no class of gentry properly so called ; but this class consists, with the exception of a few professional men not improperly mixed up with it, of tradesmen who have retired from business long enough to be entered in the mortuary registers as gentlemen. On the other hand, the pauper class is very largely recruited from the ranks of the artisans and labourers, and contains a very considerable proportion of old persons\nwho, being no longer able to earn their livelihood, have come upon the public for support.\nThe mean age of the living has been occasionally resorted to as a test or measure of salubrity. It has been assumed that a low average age of the living members of a class, when compared with the average age of another class, arises, cceteris paribus, from a high mortality leading to a quick addition of young members. This assumption is justified only in those cases in which the addition of young members can be shown not to arise from any other cause, such as an increased demand for members of the class in question. It is therefore a test to be employed with great caution; and it will also be necessary to show that the age of admission of the classes subject to comparison is the same, or open only to very slight variation.\n2. The rate of mortality. \u2014 The mortality, or rate of mortality, is the number of deaths which takes place in a given population, in a given space of time. The calculation is generally made for a year, so that the ratio comes to express the number of the living out of which one will die annually. The ratio is sometimes stated as a fraction, and sometimes as a percentage proportion. If, for instance, out of a living population of 100,000, two thousand deaths take place every year,\nTo5V5'5'7f\u00bb \u00b0r ST)\u00bb \u00b0r 2 Pel\u2019 Cent- is the mortal'ty, or rate of mortality, to which that population\nis exposed.\nIn estimating the value of this test, it is necessary to bear in mind that the rate of mortality varies for every year of life. It follows, therefore, as a natural consequence, that the rate of mortality, like the mean age at death, must be materially influenced by the ages of the living population. In a population containing a large proportion of young children, subject to a very high mortality, the aggregate rate of mortality for the entire population will be necessarily higher than in a population abounding in older persons and having a comparatively small number of children. But a very cursory examination of tables of mortality will convince us that the error attaching to the rate of mortality as a test or measure of the sanitary condition of a population is much less than that which is inherent in the mean age at death ; for not only do the extremes of life approximate much more closely to each other in their respective rates of mortality than in the mean ages at death, but ages which, though less widely separated, are far enough apart to affect the mean age at death, are exhibited as subject to a mortality very nearly identical. From 5 to 10 years of age, for example, the rate of mortality, in the male population of England, is -970 per cent., and from 20 to 30 years of age \u2018974 per cent. ; so that, while out of 100,000 persons dying at the respective ages of 5\u2014]o and 20\u201430,970 and 974 persons would die in the year, their age at death would count in the one case as something between 5 and 10, and in the other at some age between 2-5 and 30. The difference in the rate of mor-\n5 B","page":1473},{"file":"p1474.txt","language":"en","ocr_en":"VITAL STATISTICS.\n1474\ntality would be almost nothing, while the difference in the age would amount to about 20 years. So also if we compare individual years instead of terms of years. The mortality at 10 years is \"791 per cent., at 20 years *784 per cent. ; at 11 years it is *702 per cent., at 18 years .709 per cent. The rate of mortality differs very slightly in the ages brought under comparison, while the mean age at death differs by 10 and 7 years respectively.\nThese \u00e0 prion reasonings are fully borne out by the results of actual comparison. In one of the reports of the Registrar General * the expectation of life (which will be presently shown to be the true test or measure of the sanitary state of a population), the mortality, and the mean age at death, for six different populations, are compared with each other, with what result the following table will show.\nExpectation of life, in years : \u2014 Surrey, 45 ; England,41 ; France, 40; Sweden, 39; Metropolis, 37 ; Liverpool, 26.\nRate of mortality, or one death in\u2014 Surrey, 52; England, 41; France, 42; Sweden, 41; Metropolis, 39 ; Liverpool, 30.\nMean age at death, in years : \u2014 Surrey, 34 ; France, 34; Sweden, 31 ; England, 29; Metropolis, 29; Liverpool, 21.\nThe rate of mortality, then, keeps pace with the expectation of life, to such an extent, at least, as to place the six communities in the same relative position ; while, according to the mean age at death, the nations which stand third, fourth, and fifth on the list suffer transposition, France and Sweden taking rank before England in the scale of salubrity, and England, which holds, of right, the second place immediately after her own county of Surrey, is made to descend to the fourth rank. When compared, therefore, with an accurate measure of the duration of human life, the rate of mortality shows itself more worthy of confidence than the mean age at death. Nevertheless, for reasons already assigned, it must not be looked upon as altogether free from objection, and must, in every case, be regarded as of inferior value to the test next to be considered, namely,\u2014\n3. The expectation of Ife. \u2014 The expectation of life, or the mean future life-time, is the mean number of years which, at any given age, the members of a community, taken one with another, may expect to live. This expectation is embodied in those series of calculations which are technically known as life-tables, and which are so largely in use in the important operations of life-assurance. When correctly calculated, they are based on the two concurrent series of facts, the numbers and ages of the living and the numbers and ages of the dying, and they therefore comprise the two elements necessary to perfect accuracy. When based upon the ages of the dying alone, they are open to nearly the same objection as those which apply to the mean age at death.\nThe following is an abbreviation of the Flnglish life-table, which will be found given * Sixth Annual Report, p. 572.\nat length for any year of life from birth to 95 years of age in the fifth annual report of the Registrar General.*\nAge.\tMales.\tFemales.\n0*\t40-19\t42*18\n1*\t46-71\t.47-55\n2*\t48-82\t49*57\n3-\t49-52\t50*29\n4-\t49-74\t50-48\n5*\t49-64\t50-38\n10*\t47-08\t47-81\n15*\t4335\t44-13\n20*\t\u2022 39-88\t40-81\n25*\t36-47\t37-52\n30*\t33-13\t34-25\n40-\t26-56\t27*72\n50*\t20-02\t21-07\n60*\t13-59\t14-40\n70*\t8-51\t9-03\n80*\t4-92\t5-20\n90*\t2-68\t2-77\n95*\t2-22\t2-06\nThe table is read thus : \u2014 At birth the expectation of a male child is 40*19 years, of a female child 42*18 years ; at 5 years of age the expectation is 49 64 years for a boy and 50*38 years for a girl ; at 20 years of age, males one with another may expect to live 39*88 years, and females 40*81 years ; at 30 the expectation has fallen to 33*13 for men and 34-25 for women.\n4.\tThe mean duration of life, the mean life, the mean life-time, or vie moyenne, is found by adding the age to the expectation of life. Thus the mean duration of life at 5 years of age is 5+49-64 for boys, and 5+50-38 for girls, or 54*64 for boys and 55'38 for girls ; at 10 years of age the mean duration of life is, for boys and girls respectively, 10+47*08 and 10+47*81, or 57*08 and 57 81 ; and at 30 years of age 30+33-13 or 63-13, and 30+34*25 or 64*25. The mean duration of life differs from the mean age at death, inasmuch as the one is a calculation based on all the deaths taking place, after a given age, in the members of a community traced through life, while the other is founded upon such deaths as happen to be noted in a community which has been undergoing continual disturbance by births, immigration, and emigration.\n5.\tThe probable duration of life, probable life-time, equation of life, or vie probable, is the age at which a number of children born into the world will be reduced one-half, so that the chance is equal of their dying before or after that age. Thus it has been ascertained that out of 51,274 males and 48,726 females (making up together the number of 100,000 infants) at birth, 25,637 males will die between the 45th and 46th year, or at about 45\u00a3 years of age, and 24,363 females between the 47th and 48th year, or at about 47\u00a3 years ; so that the equation of life or probable life-time of males at birth is 45\u00a3 years, and of females\n* Report, p. xix.","page":1474},{"file":"p1475.txt","language":"en","ocr_en":"1475\nVITAL STATISTICS.\n41\\ years. The same terms (probable lifetime, equation of life, or vie probable) are also employed in speaking of persons who have attained more or less advanced ages. Thus the probable duration of life of a female at 25 years of age is about 41 years, being her actual age added to the number of years required to reduce the females living at that age to one half. In like manner the probable duration of life of a male aged 60 years is 73 years, being his age added to the 13 years required to reduce himself and his contemporaries to one half their number.\nThe term \u201cspecific intensity\u201d has also been used as a measure of the value of life. It represents the number living at any given age, divided by the number dying at that age. For example, if, at the age of 44, 72,709 male survivors of the population of England and Wales, out of 100,000 born into the world, lose by death 990, the specific intensity is\tor 73475, while for the\nnumber of 72,190 female survivors losing 923 of their number, the specific intensity is -flf-, or 78409. Females, therefore, have a higher intensity of life at 43 years of age than males ; in other words, they suffer from a less mortality.*\nSuch are some of the principal methods which have been recommended or employed for ascertaining the true duration of human life, _a branch of statistical inquiry which has received large contributions of late years, many of which, however, are unfortunately rendered altogether valueless by the omission from the calculations of some elements necessary to precision, but not yet obtainable.\nBibliography. \u2014 1. The fifth and sixth .annual Keports of the Registrar General. \u2014 2. Contributions to Vital Statistics. By F. G. P. Neison, Esq. 3. Quarterly Journal of the Statistical Society, vol. vn. Essays by Edwin Chadwick, Esq. and E h. P. Neison, Esq. at pp. 1. and 40. On the subject of the Construction, Properties, and Applications of Life Tables, which is intimately connected with Vital Statistics, many interesting details and full references to authorities will be found in Mr Farr s letters to the Registrar General in the fifth and sixth Annual Keports.\t(m J. Guy.)\nVOICE.f \u2014 (Syn. Gr. Qui y ; Lat. Vox ; Fr. Voix ; Germ. Stimme ; It. Voce; Span. Voz.) This term is usually applied to those sounds which animals produce by means of the air traversing their organs of voice, such as we observe in mammalia, birds, reptiles, and\nin some insects.\t\u201e\t,\nThe human voice is susceptible of several modifications, such as timbre or quality, intensity, and pitch ; including those successive transitions of tone from one pitch to another which constitute melody. The organs of voice comprise the thorax with the muscles\n* See Contributions to Vital Statistics. By F G P. Neison, F. L. S. &c., p. 5.\n+ fit was intended that this article should have comprehended Voice and Speech. It is now found necessary to defer the latter subject to the Supplement. Ed.]\nof respiration, the lungs, trachea, larynx, pharynx, mouth, tongue, nasal cavities, nerves, and blood-vessels. Of these, the thorax and lungs may be considered an air-chest or bellows, the trachea a porte-vent or air-pipe, and the glottis a complex reed. The trachea varies in length and diameter with the age and sex of individuals, until they arrive at the adult period of life. By its structure the trachea is endowed with elasticity, together with the power of longitudinal extension and relaxation, and of increasing or diminishing in diameter : the acoustic effect of these properties will presently be investigated.\nThe sum of the areas of the two bronchi is greater than that of the trachea ; by which adaptation the latter is more readily supplied with air during the vocalization of the breath. In all mammalia, birds, and reptiles, the axes of the bronchi are inclined to that of the trachea at a greater or less angle. With reference to the voice, the larynx is the most important organ in the whole apparatus. The mouth, fauces, tongue, and nasal organs are not necessary to the production of voice ; nevertheless they exercise a considerable influence on its quality, and are indispensable for the production of articulate language. The thorax is sufficiently capacious to contain as much air after a full inspiration as will sustain the glottis in a state of vibration, when the tone is of moderate intensity, during the space of fifteen seconds, which will enable a person to pronounce in rapid succession from thirty to forty monosyllables at one expiration.*\nThe phenomena of the voice of animals must at a very early period have afforded to physiologists proof of the susceptibility of membranous structures to enter into a state of vibration ; and it is now generally known that membranes, whether twisted into a cord like the string of a violin, or in the form of a parallelogram stretched in one direction as the vocal ligaments, or in that of discs stretched all round as the head of a drum, are all capable of producing musical sounds when properly excited.\nThe theory of the vibratory movements of stretched membranous surfaces has occupied the attention of many of the most celebrated mathematicians, such as Euler, Bernoulli, Riccati, Biot, Poisson, Sir John Herschel, and others. It is a subject requiring the most profound analysis, and the solution of problems of much greater complexity than those either of strings or bars ; but in order to bring the theory of vibrating membranes within the reach of computation, the membranes are supposed to be homogeneous and of equal thickness and elasticity. Now this hypothesis will not satisfy the conditions of the vibratory movements of the vocal organs, such as the windpipe for example, which is composed of tissues of variable thickness, density, and elasticity; it would therefore be\n* For the anatomy of the human larynx, reference is made to the article Larynx.\n5 b 2","page":1475},{"file":"p1476.txt","language":"en","ocr_en":"1476\tVOICE.\nfutile in the present state of the science of acoustics to attempt any mathematical solution of the laws of the equilibrium and movements of the heterogeneous masses of the vocal tube. When, however, a membrane is stretched in one direction only, it obeys the same laws as a string.\nFig. 890.\nAn outline of the transverse section of the Human Larynx. ( Outline of fig. 18, Vol. III. p. 100, in which the different parts are indicated.')\nx, x, the plane of the vibrating position of the vocal cord ; y, y y, y, the plane of the respiratory position.\nHaving adapted two laminae of India rubber to a pipe connected with the bellows of an organ, M. Biot caused a current of air to pass over their free edges, by which means he obtained with facility sounds of different pitch. Professor Willis made similar experiments with leather and caoutchouc, but could not produce with these substances so great a range of tones as the glottis will yield, and therefore concluded that the vocal ligaments possess greater elasticity. Mr. Willis has also investigated the position in which it is necessary that membranous laminae should be placed, in order that they may be excited and sustained in a state of vibration. He has likewise given a satisfactory explanation of the mode of action of the air on reeds, such as those of the organ pipe, which applies also to free reeds, and every other case where a vibratory motion is maintained by a current of air.\nThe experiments and theory of Mr. Willis\nare exceedingly important, for he has shown that in ordinary breathing the vocal cords remain inclined to each other, at an angle which prevents any vibratory motion ; whereas when their surfaces lie in the same plane, the breath immediately excites them into a state of vibration ; the natural position of the vocal cords in these two states is seen in (fig. 890). M\u00fcller also made some experiments on stretched membranous bands, both isolated, and in connection with a tube ; from which he concludes that the force of the current of air influences the pitch of the note produced ; so that a strong current will produce a more acute tone than a weak one, and vice versa ; but the author has not found this to be the case in any of the experiments which he has made. To obtain a pure quality of tone when twro membranous bands are stretched across a tube, it is necessary that they should be of equal weight and length, and subjected to equal tension, otherwise they cannot vibrate freely in equal periods of time. According to Cagniard De la Tour, if two membranous laminae of equal length and weight be stretched by unequal forces, so that there is an interval of a fifth between the notes they yield separately, the note resulting from their combined action is the intervening third. M\u00fcller is disposed to doubt the accuracy of De La Tour, but his own views do not differ materially from those of the latter, as he says that when one tongue is most readily thrown into vibrations bv the current of air, the sound is emitted by it alone, but if the blast is such that it throws them both into motion, they may both vibrate together, and by reciprocation produce a simple sound intermediate between the fundamental note of the two vibrating separately ; they may also emit two distinct sounds, or the blast being modified, the two sounds may be produced in succession. From these researches it appears, that membranous laminae, stretched in imitation of the thyro-arytenoid ligaments, will not only vibrate readily, but produce a range of musical tones. It has been remarked that sounds are most readily produced when the two laminae are stretched in the same plane, and that a smaller volume of air is required the nearer the edges of the laminae approach each other, and a still smaller one when their edges actually touch. De Kempelen states, that to produce sound, the edges of the glottis must be approximated to within or at least -JL., of an inch. These experiments upon artificial vibrating tongues perfectly agree with those the author has made on the larynxes of animals. Owing to the nature of the articulation of the thyroid with the cricoid cartilage, and the manner in which the crico-thyroid muscles act, an equal tension of both the thyro-arytenoid ligaments is simultaneously secured, supposing the arytenoid cartilages to be at the same time in corresponding positions, which is a necessary condition for the production of a synchronous vibratory motion in the two lips of the glottis.","page":1476},{"file":"p1477.txt","language":"en","ocr_en":"VOICE.\n1477\nIf the larynx of an animal be dissected out, and the vocal cords be stretched, they will vibrate like a piece of caoutchouc or leather in a current of air. In conducting these experiments, it is necessary to secure the same conditions as those which are required in the laminae above mentioned ; for instance, the inner edges of the glottis must be turned towards each other till they are in the same plane and parallel to one another before they will produce any sound ; hence we infer, that when the tension of the arytenoid ligaments takes place in the living animal, they turn upon their axes till their planes (which in the state of relaxation are inclined to the axis of the vocal tube) become perpendicular to it, and as the edges of the glottis approximate, and its chink is nearly or entirely closed up, they acquire the true vibrating position. The production of the most simple tones of voice requires the associated actions of a most extensive range of organs ; and it is calculated that in the ordinary modulation of the voice, more than one hundred muscles are brought into action at the same time.\nThe lungs having been first supplied with air by the act of inspiration, and the air in the chest and trachea having subsequently been condensed by the muscles of expiration, a portion of the edges of the glottis yields to its pressure, and is curved upwards, so as to form an angle with the axis cf the vocal tube, leaving between them a narrow aperture through which the air escapes. The tension and elasticity of the vocal ligaments tend to restore them to the plane of the vibrating position ; the air having been rarefied below the glottis during their elevation, becomes condensed on their depression, and the necessary force is again accumulated to reelevate the vocal ligaments,and thus an oscillating movement, consisting of a partial opening and closing of the glottis, takes place, which being communicated to the contiguous air, the sounds of the voice are produced.\nThe relative length of the vibrating edge of the glottis is regulated by the pressure of the column of air in the trachea, and the resistance of the vocal ligaments. The intensity of the voice in the same medium, and under similar collateral circumstances, depends on the pressure of the column of air in the trachea, and the range of motion performed by the vibrating edges' of the glottis. The vocal ligaments do not vary the pitch of the voice by their tension alone, but by their variations in length and tension conjointly. The author has learnt this from his own experiments on the vocal functions of the larynx, which have been confirmed both by Majendie and Mayo ; the former having observed in the larynx of a dog that a longer portion of the ligaments of the glottis vibrated during the utterance of grave tones, and that the length was diminished as the tones became acute. The latter had an opportunity of inspecting the movements of the glottis in a man who had made an attempt to destroy himself by cutting his\nFig. 891.\nThe Head and Vocal Organs prepared for experiments. (After M\u00fcller.)\nThe cervical vertebrae are removed, and the oesophagus opened behind the arytenoid cartilages, which are fixed together by a strong pin and ligature ; the latter is brought through the opening, which is then firmly sewed together, and the lower opening of the oesophagus is also closed up. The larynx is laid bare, and the superior portion of the thyroid cartilage carefully removed so as not to in]ure the mucous membrane of the larynx. The parts thus prepared are firmly fixed against the column, to which the arytenoid cartilages are also attached by the cord which binds them together. The trachea is connected with a pipe and bellows for the supply of air. a, the trachea; b, the os hyoides ; c, the cricoid cartilage ; d, portion of the thyroid cartilage remaining for the attachment of the cords e, by means of which the vocal cords may be extended ; /, apparatus for compression.\nFig. 892.\nThe apparatus used for the lateral compression of the vocal cords, as seen in fig. 891 f.\n5 B 3","page":1477},{"file":"p1478.txt","language":"en","ocr_en":"1478\nVOICE.\nthroat. In this case the larynx was divided immediately above the vocal cords, and in consequence of the oblique direction of the wound, the arytenoid cartilage and the vocal cord on one side were injured. During respiration the glottis was observed to assume a triangular form, but when a sound was uttered, the chordae vocales became nearly parallel, and the rima glottidis of a linear form. The posterior part of the aperture did not appear to be closed. In a second case of this kind, he observed that the arytenoid cartilages, as long as the vocalization of the breath continued, maintained the position which they had assumed when the glottis was closed entirely.* * * \u00a7 The vibrations of the thyro-arytenoid ligaments are considered by Ferrein f to be analogous to those of strings ; hence he denominated these ligaments (though improperly) chordae vocales. He imagined that the longitudinal tension of these cords alone governed the pitch of the voice. Mr. WillisJ has embraced the hypothesis of Ferrein ; he observes, that to obtain the various notes of the glottis, it is only necessary to vary its longitudinal tension after the ligaments have been placed in the proper position i but M. Biot \u00a7 remarks, \u201c Qu\u2019y a-t-il en effet dans la glotte qui ressemble \u00e0 une corde vibrante? Comment pourroit-on en tirer jamais des sons d\u2019un volume comparable \u00e0 ceux que l\u2019homme produit ? Les plus simples notions d\u2019acoustiques suffisent pour faire rejeter cette \u00e9trange opinion.\u201d\nOn inspecting the larynx from above, we see two very nearly rectangular-shaped laminae, one on each side of the chink of the glottis, but nothing resembling an isolated cord. The mucous membrane which lines the thyro-arytenoid ligaments (to which it closely adheres), as well as the rest of the vocal tube, must be considered as forming a part of the weight of the vibrating surface upon which the air acts ; the thyro-arytenoid ligaments confer on this membrane the requisite tension and resistance during vocalization, and it is this membrane which gives the sides of the glottis their laminated figure. The vocal ligaments, with their lining membrane, are stretched by the thyro-cricoid muscles, not all round like a drum, but in one direction only, namely, in that of their length, being attached on three sides, leaving one only free to vibrate. The vocal cords are, as h is been seen, rectangular-shaped membranes, and from experiments made on the larynx after death by Ferrein, M\u00fcller, and others (which the author has repeatedly verified), are found to vibrate like cylindrical cords ; we will therefore apply to the former the well-known formulae which regulate the vibrations of the latter.\nIn cords composed of the same material,\n* Mayo, Outlines of Physiology, p. 991.\nf M\u00e9moires de l\u2019Acad\u00e9mie. 1741. p. 400.\nX Cambridge Philosophical Transactions, vol. iv.\n\u00a7 Pr\u00e9cis Elem. de Phvs. tom. i. p. 398.\nand of uniform thickness, the time of a complete musical vibration, or double oscillation, is\nwhere l is the length of the cord, p its weight, P the force with which it is stretched, and g\u20141 GtV feet.\nIn order to apply this formula to the vocal ligaments, let a be their depth, b their breadth,\nFig. 893.\nThe apparatus employed for making experiments on the Human Larynx. (After M\u00fcller.)\nN, shaft or column for the attachment of the larynx ; f the forceps for compressing the larynx laterally ; u, the bellows pipe ; v, the manometer connected with the tube u, for estimating the tension of the air used in the experiments, m, o, columhs for the attachments of the pulleys x' and y' ; x, a line by means of which the vocal cords are extended in the direction of their length ; it passes over the pulley x< \\ y, a line passing over the pulley y', by means of which the vocal cords may be relaxed and reduced to their minimum length, thus performing the office of the crico-thyroid muscle ; z, a line by means of which the vocal cords may be extended by drawing them downwards and forwards.","page":1478},{"file":"p1479.txt","language":"en","ocr_en":"!\nVOICE.\n1479\nand 8 their specific gravity ; then p will be equal to abld, and equation (1.) becomes\nand the number of such vibrations in will be\nN=\nVggF 2 W abd\n- (3)\nWe observe, in the first place, that if all other things remain the same, the number of vibrations varies inversely as the length of the cord ; hence, if the vocal ligaments were divided by nodes into n ventral segments, each segment might be considered a separate vibrating ligament, whose length would be \u2022^th of the vocal cord, and consequently the number of its vibrations in a given time would be n times as many as that of the whole cord.\nOwing to the elasticity of the thyro-aryte-noid ligaments, their lengths, when in a state of repose, differ considerably from those which they present under the greatest tension. They\ndiffer also in the two sexes. In a series of experiments by Muller, the differences of length were observed to be as represented in the following table, the figures of which are in inches and decimals of an inch. From these experiments it appears that the lengths of the male and female vocal cords in repose are nearly as 7 to 5, and in tension as 3 to 2. In boys at the age of fourteen, the length is to that of females after puberty as 6\u201925 to 7, so that the pitch of the voice is nearly the same. These experiments afford an idea, although an imperfect one, of the elasticity of the vocal ligaments. It has always been a subject of surprise, if thethyro-arytenoid ligaments obey the laws of strings, how such short and narrow lamin\u00e6 should produce such very grave tones as many bass singers are capable of uttering ; and this struck M. Biot as one of the circumstances which in his opinion prove their mode of vibration to be unlike that of strings. He asks, \u201c O\u00f9 pourroit-on trouver la place n\u00e9cessaire pour donner \u00e0 cette corde la longueur qu\u2019exigent les sons les plus graves ?\u201d\nSubjects of Experiment.\tNumber of Experiments.\t\t\t\t\t\n\t1.\t2.\t3.\t4.\t5.\t6.\nMale in a state of re-pose -\t-\t- J\t0-7087\t0-63\t0-63\t0-83\t0-748\t0-748\nMale in the state of 1 greatest tension - J\t0'83\t0-83\t0-984\t1-0236\t0-9055\t0-9055\nFemale in a state of\"l repose\t-\t- j\t0-47244\t0-47244\t0-551\tBoy of 14 in repose. 0-414\tI\t\t\nFemale in the state of! greatest tension - J\t0-63\t0-59\t0-63\tBoy of 14 grea 0-571\ttest tension.\t\nMean length in male -\tIn repose. 0-72834\tGreatest tensi 0-912070\ton.\t\t\t\nMean length in female\t0-49868\t0-61679\t\t\t\t\nThe author is acquainted with some bass singers who can produce the note C which results from sixty-four musical vibrations. Let us now investigate this phenomenon more closely, and endeavour to explain how such grave tones are produced by such extremely short membranes. M\u00fcller has contrived several ingenious pieces of mechanism, seen in figs. 891, 892, and 893, by means of which he was enabled to estimate the amount of tension, lateral compression, and atmospheric pressure on the vocal cords, during the production of sound. In order to find the variations in the amount of condensation of air in the vocal organs in the production of sounds differing in pitch and intensity, the apparatus was furnished with a manometer (fig. 893, v). From that portion of the experiment which was confined to the investigation of the effects produced by tension of the\nvocal, compared with that of musical cords, he obtained results which are recorded in the following table.\nNumber of Experiments.\tWeights employed.\t\t\n\t4 loths.*\t16 loths.\t64 loths.\n1\tc\tA>\tG\u2019S\n2\tCl\tB1\tA2S, A2\n3\tG'S\tC2S\tC3\n4\tA1\tD2\tC3\n5\tAS\tF'S\tG2\n6\tAS\tG:S\tG3\n7\tD>\tC2\tA2\n8\tD'S\tB1\tA2\n9\tG\tG1\tf G2 both octaves imperfect.\n* A loth = 225-5531 grs. English.\n5 B 4","page":1479},{"file":"p1480.txt","language":"en","ocr_en":"1480\nVOICE.\nIn the above table C1 answers to 256 vibrations. Muller states that the numbers of vibrations in these experiments are not exactly in the direct ratio of the square roots of the stretching forces, and that the weights 4, 16, 64, did not produce the octaves, but generally from a semitone to two or three tones lower. Now this result should have been anticipated ; but it does not seem to have occurred to him that whilst he increased the tension he at the same time increased the length, and we know (eq. 3.) that the number of vibrations in this\n.\ta/ tension\t,\ncase varies as \u2014\tand conse-\n^/length of cord\nquently the numbers actually produced by the weights above mentioned ought (agreeably to Midler\u2019s experiments) to be less than those which correspond with octaves. We see by the first experiment in the above table that the tension sufficient to produce 818 musical vibrations is 64 loths, or very nearly 33 ozs. If, therefore, we take the mean length of the vocal ligaments under the greatest tension at \u202291 of an inch, and substitute in equation (3.) their values for all known quantities, remembering that P represents the tension of one vocal cord, we shall find the weight of each ligament, viz.\n\u201cMS=!^=1'l44grs\u2018 -(*\u2022)\nIn an adult male I found that the two vocal ligaments, when divested of mucous membrane, weigh one grain, which is scarcely one-half their weight by theory ; hence it appears that a considerable portion of mucous membrane is connected with the vocal cord in the production of sound, which agrees with the anatomy of these parts.\nIt is now necessary to offer some explanation respecting the vital state of the vocal ligaments. The state of repose is the ordinary condition of the vocal ligament in the living subject, when the voice is not exercised ; but we must not therefore conclude it to be incapable of further contraction. In fact, the state of repose during life is a state of tension, for the ligaments being connected with the thyro-arytenoid muscles, not in a few points, but continuously throughout their whole length, must obey the motion of these muscles, which, like all other muscles, are in a state of tension during repose. We also know by experience that when we produce a sound lower than the usual pitch of our voice, the crico-thyroid chink is opened principally by the contraction of the same muscles, and the ligaments must therefore at the same time be relaxed. It appears, then, both from the anatomy and physiology of the human larynx, that the ordinary state of the vocal cords is one of considerable tension, which admits of being lessened, and thereby produces the range of lower notes. If we suppose the glottis to be partially closed when we are talking, that is, at the ordinary pitch of our voice, and to be more opened as the tones become graver, this of course will co-operate with\nthe relaxation of the vocal cords. In the production of the higher notes, the cricothyroid chink closes, and the thyro-arytenoid muscles, and consequently the ligaments, are elongated. Since, therefore, the vocal ligaments have been proved to extend and contract for acute and grave tones respectively, and after death vibrate in a great measure like musical strings, we think it may be fairly inferred that they likewise obey, to a certain extent, during life, the laws of the vibrations of such strings, and that the conclusions which we have derived from the foregoing formulae are not far removed from the truth. A further confirmation of these views may be derived from the following considerations. The length of a cord of invariable weight varies directly as the tension, and inversely as the square of the number of vibrations. Now, if we assume the length of the vocal cord, which gave G2$ under a tension of 32 loths to be \u201991 inch, which is the mean length of the male vocal cord in its greatest tension, according to the first table, and which gave the notes A1 C1, under the tension 8 and 2 loths respectively, the corresponding lengths of that cord, according to the formula, will be \u201983 inch and *58 inch*; but \u201958 inch is less than the least length in repose in the table. This result is, however, quite consistent with the theory here proposed ; because after death the thyro-arytenoid muscle becomes of itself elongated, and consequently the vocal ligament attached to it, and therefore the length of the ligament must be greater in this state than when it is in that which we have defined to be the state of repose before it has lost its vitality.\nIn experiments made on the larynx by stretching the vocal ligaments with given weights, and by forcing a current of air through the glottis, care must be taken to keep the organs moist, and of the same temperature as they possess during life. The amount of condensation of the air in the vocal tube has been ascertained by Cagniard De la Tour, and Midler, the former in the living, and the latter in the dead subject. In a person who had an opening in the windpipe after the operation of tracheotomy, Cagniard De la Tour found that the tension of the air in the vocal tube, while blowing the clarionet, was equal to a column of water of thirty centimetres jn height, and that to produce a simple vocal sound in the same person a tension of sixteen centimetres was necessary. M\u00fcller found that he could produce sound in a larynx artificially by a tension of 3\u20194 centimetres; but for very loud sounds an increased tension was requisite. The discrepancy between the experiments of Cagniard De la Tour and M\u00fcller may be ascribed to the circumstance that the one operated on\nV\"p\t. p\n* N varies as , ; I varies as \u2014, then *91 inch\nV 1\tA2\nI length of cord for A1 ; :\tthe length\nof the cord for A1 = -83 inch ; and the length for C1 = -58 inch.","page":1480},{"file":"p1481.txt","language":"en","ocr_en":"VOICE.\n1481\nthe living vocal organs, but in a state of disease, the other on the organs after death.\nVariations in the hygrom\u00e9trie and thermo-metric states of the air exert very powerful influence on the pitch of the voice ; during the prevalence of a cold moist state of the atmosphere, especially in England, the voices of singers become lower by two or three notes, and regain their usual pitch when the air becomes dry.* In thus tracing out the analogy between the laws of stretched cords and those of the vocal ligaments, it is not intended that those ligaments should be considered as stringed instruments, but only that this analogy is accurate as far as relates to the velocity with which an impulse is propagated along them. Dodart f supposed the tension of the vocal cords to be merely subservient to an alteration in the size of the aperture of the glottis, and that the difference of of a fibre of silk, or 3 Vp of a hair in the dimensions of that aperture, was sufficient to alter the pitch of the voice ; but this has been so completely refuted by more recent physiologists, and is so directly at variance with acoustic principles, that we need not give illustrations of its fallacy. M. Savart considered that the action of the air in its passage through the ventricles of the larynx, between the superior and inferior ligaments, is really the source of sound, and analogous to the mechanism of the bird-call or dog-whistle. J There is certainly a great resemblance in the structure of that instrument to the space above mentioned in many of the higher animals, which might easily have led to this ingenious hypothesis ; but, as we find neither superior ligaments nor ventricles of Morgagni in many of the order Ruminantia, in which the voice is very sonorous, this theory (as M\u00fcller remarks) is untenable.\nWe next come to the consideration of the alleged analogy between the action of the vocal ligaments and that of the reeds of musical instruments. This opinion is maintained by MM. Biot, Cagniard De la Tour, Majendie, Malgaigne, M\u00fcller, and several other distinguished scientific men. It is opposed principally by M. Savart, who observes that the essential principle of the action of reeds consists in the periodical opening and shutting of the orifice through which the stream of air passes, but that this is wanting in the glottis ; and that were the latter a reed, the edges of the thyro-arytenoid ligaments which form the sides of the chink w ould be alternately forced asunder by the column of air in the larynx, and brought together by their tension ; whereas he found by experiment that air blown through\n* When Grassini came to this country, owing to the change from the air of Italy to that of England, her voice became one octave lower: after singing for two or three seasons, her natural voice returned, but it had lost its attractions with the low tones which had obtained her the greatest applause. Transactions London Medical Society, New Series, vol. i. 1846 ; art. Aphonia, p. 36.\nf M\u00e9m. de l\u2019Acad. des Sciences, 1700. 1701.\nJ See fig. 890.\nthe glottis produced sound although its edges were from one-sixth to one-fourth of an inch asunder. M. Savart has however clearly mistaken the circumstance wherein the essential principle of reeds consists, since those of the clarionet, bassoon, hautboy, &c. do not entirely close the apertures through which the breath passes ; and this is likewise the case with the natural reed formed by the lips of players on the flute and horn. There is in all probability a double action of the vocal cords in the production of sound ; the one being a vibratory motion throughout their length similar to that of a musical string, and the other an oscillation like that of a reed, forming a partial opening and closing of the glottis. The author is led to adopt this view of the functions of the vocal organs from considering that every circumstance which he has established in his previous investigation of their action when treated as cords, is perfectly consistent with the hypothesis of their vibrating like the tongues of reeds ; for let us now suppose them to be simply membranous tongues. In this case the axis of motion is the edge of the ligament attached to the thyro-arytenoid muscle ; the vibrations take place in a plane perpendicular to the axis of that muscle, and the length of the tongue is the breadth of the ligament. The author has observed in repeated experiments on the larynx after death, that the chink of the glottis was partially opened and closed in the production of sound, and M\u00fcller found that by decreasing the breadth of the ligament he rendered the note more acute ; but as this breadth is so small, being in its ordinary state in an adult generally less than one-tenth of an inch, it is extremely difficult to measure the variations corresponding with different notes ; and the author cannot learn that any one has yet succeeded in determining these varying lengths with sufficient accuracy to form data for the application of the mathematical formulae of elastic vibrating tongues.* We know that the number of vibrations made by the same tongue in a given time varies inversely as the square of its length. If, therefore, a tongue whose length is only \u20181 inch give any note, the length necessary to produce the octave will be \u201807 inch, that is, the variation will be only *03 inch ; we see then how minute must be the changes answering to the intermediate notes, and consequently how much more difficult it is to determine them in the vocal ligament when considered as a tongue than as a stretched membrane or cord. It is moreover observable that the extension and relaxation\n* The formula of Giordano Riccati is N\nL2 V G\nwhere N is the number of vibrations, D the thickness, and L the length of the tongue or rod, R its rigidity, G its specific gravity, g the space through which a body\" falls by gravity in l\", and n a number \u2018constant for each mode of vibration, depending on the number of nodes.","page":1481},{"file":"p1482.txt","language":"en","ocr_en":"VOICE.\n1182\nof the vocal cord, which, as we have seen, are analogous to those of a musical string, produce a corresponding shortening and elongation of its axis, regarded as a tongue ; and lastly, since one tone only is produced at a time, the vibrations resulting from the double action which appears to exist in the vocal apparatus must be synchronous.\nWe have seen how nearly, when we take into account the delicacy and difficulty of the experiments, their results agree with the theory that the vocal cords are subject to the same laws as other stretched lamin\u00e6, and it would be highly interesting to compare these results with the simultaneous variations which they undergo transversely, and thus discover how far the laws of vibrating elastic tongues may be applied to them. It might possibly be objected to the idea of this twofold action, that the production of sound by the vocal cords is sufficiently accounted for by supposing them to vibrate merely as elastic tongues ; but then it is found by experiment, that by artificially dividing their length into two ventral segments, there results the octave of the fundamental note, which proves that at all events they vibrate as cords. In conclusion, we must ever bear in mind the vast difference between natural and artificial mechanism, and however complicated a problem it may be to determine that constitution of the vocal apparatus, by which the thyro-arytenoid ligaments may simultaneously obey the laws of cords and tongues, yet to a physiologist who is accustomed to meet with the most admirable contrivances and combinations in the animal frame, the difficulty of finding a strictly mathematical solution is, in such a case, no objection to its truth, wlien the facts, as far as they have been observed, are decidedly favourable to its reality. Were the movements of the glottis independent of any tube or column of air, the study of the functions of the vocal organs would be much more simple ; but we find it situated nearly in the centre of the vocal tube of which the trachea and bronchi are the inferior, and the upper part of the larynx, pharynx, nose and mouth, the superior portion ; we have therefore to consider the influence of this tube, and of its inclosed column of air in the production of voice.\nIn order to investigate the mutual relations between a reed and a pipe, two methods may be adopted : one of these is to vary the pitch of the reed w'hile the length of the pipe remains constant, and the other to vary the length of the pipe with a reed sounding one tone only when detached from the tube. In the construction of reeded pipes for musical purposes, it is incumbent on the mechanician to adjust the length of the tube to the pitch of the reed. When a free reed is used on the principle of Kratzenstein or Greni\u00e9, it is found that, if the pipe be not in perfect unison with the reed, the purity of the tone decreases within certain limits, as the discordance between the reed and pipe increases. The researches of MM. Biot, Weber, Willis\nand Miiller have greatly enlarged our knowledge on this subject. We learn from their experiments how great an influence is mutually exerted between a pipe and its reed, when the pitch of the one is made to vary while the other remains constant, and we may conclude that analogous effects are produced between the vocal tube and the glottis. The slightest knowledge of acoustics is sufficient to inform us that the pitch of any pipe, such as the organ, the flute, the trumpet, in short of all musical tubes vibrating in a similar manner, depends on the velocity of an impulse propagated in the air within, and is determined by the length of the pipe. As long as the tubes of musical instruments remain rigid, the nature of the materials which compose them does not affect the pitch of the sound, but merely influences the quality of the tone, and it is indifferent whether we employ metal, wood, or paper in their construction ; each of these substances will yield a tone of a particular timbre, or quality, depending on the nature of the motions produced among its particles by the friction of the air on its surface; but the pitch will be the same in each, if the lengths of the pipes be equal, proving that the air itself is the source of sound. When, however, the sides of the tube are composed of flexible membranes, the inclosed air has a vibratory motion, conjointly with, and subordinate to, that of the parietes of the tube, whereby the pitch of the sound is affected, as well as its quality. M. Savart* found that by taking tubes composed of layers of paper of constant length, but varying in thickness, graver sounds were produced as the parietes became thinner, and that the gravity of the sound was increased by moistening and relaxing the sides of the tubes. We shall presently see the application of these facts to the vocal apparatus.\nWe find the flexibility of the trachea and bronchi capable of being varied by the operation of two forces, the one longitudinal or parallel to the axis of the tube, the other transverse. The first of these comprises the muscles which elevate and depress the larynx; the latter, the cartilaginous segments of rings perpendicular to the axis of the tube having muscular fibres attached to their posterior extremities, the contraction and elongation of which regulate the diameter of the trachea. The pharynx, mouth and nasal cavities, which form the superior extremity of the vocal tube, are also provided with muscles to modify the tension of that part of the tube so that it may vibrate synchronously with the rest. The necessity for this change in the dimensions of the tube, in order that it may vibrate in unison with the glottis, is in accordance, not only with the joint system of pipe and reed above described, but also with what actually takes place in the vocal organs of living animals. When the voice is raised in the scale from grave to acute, a corresponding elevation takes place in the larynx towards\n* Annales de Chemie et de Physique, tom. xxxii.","page":1482},{"file":"p1483.txt","language":"en","ocr_en":"1483\nVOICE.\nthe base of the cranium. By placing the finger on the pomum Adami this motion can be easily felt, and at the same time the thyroid cartilage is drawn up within the os-hyoides, and presses on the epiglottis ; the small space between the thyroid and cricoid closes, the pharynx is contracted, the velum palati is depressed and curved forward, and the tonsils approach each other : the reverse of these phenomena takes place during the descent of the voice. These are the principal phenomena common to most mammalia which can be recognised by external observation ; the other changes being, on account of their situation, invisible.\nThe effects of these variations on the tone of the voice have been hitherto little understood. It has always appeared incomprehensible why the vocal tube should apparently increase in length in the production of the acute tones, and shorten in the grave ; a circumstance which theoretically presents an acoustic paradox. Dodart and many others have conceived the elevation of the larynx to be merely for the purpose of shortening the vocal tube in the supra-laryngeal cavity, and have considered the trachea as producing no effect on the pitch of the tone. Majtndie has also pointed out the shortening of this part of the tube. In order to ascertain the effect of these changes, the following expeii-ments were made on the dead body. Having laid bare the vocal organs of an adult male, I raised the larynx to the position it would occupy by the elevation of the voice to an octave, being about half an inch, and at the same time minutely observed the position of the lowest ring of the trachea with reference to the sternum. By this operation 1 found the trachea was raised out of the chest, nearly to the same extent as the larynx had been elevated towards the base of the skull. The next step was to examine whether any change had taken place in the diameter of the tube. For this purpose, having measured the diameter of the trachea in its natural position, the larynx was again elevated to the, same extent as before, when the diameter was found diminished one-third. These experiments prove that, contrary to the general preconception, the elevation of the larynx shortens the tube independently of the contraction between the thyroid cartilage and os-hyoides, and at the same time lessens its diameter. The same effects may easily be detected during life by placing the finger on the trachea immediately above the sternum during the elevation of the larynx, when the trachea is found to ascend out of the chest, and afterwards to return to its former position ; a movement in which the lungs and bronchi participate. The alteration of the tube in diameter may also be perceived by grasping the trachea with the finger and thumb during the elevation and depression of the larynx.* These movements are so striking as to lead\n* Essays by the author, in the London and Edinburgh Philosophical Magazine, for September, October, and November, 1836.\nirresistibly to the conclusion, that there exists a constant adaptation between the tension and the vibrating length of the thyro-arytenoid ligaments and the walls of the vocal tube, in the production of tones of the ordinary register; for we have seen that the variations of the vocal cords, at least as far as relates to the modulation of sound, are perfectly independent of the length of the vocal tube, and consequently the changes in its length which we have just described are not at all necessary for that purpose. Again, the vocal tube is so short, that, as has been ascertained by Weber and others, it could not, were it rigid, affect the pitch of the note produced by the glottis. As however this tube is composed of flexible materials, its effects are similar to those observed in M. Savart\u2019s experiments ; that is, the relaxed state of the parietes compensates for its want of length, and enables it to vibrate synchronously, and therefore to give forth sounds equally grave with those of the glottis, thereby reinforcing the tone which would indeed be produced, though with much less intensity, without this aid.\nThe Falsetto, or vocedi testa, has always been considered a most embarrassing subject of research, and its peculiar quality has excited the attention both of the physiologist and of the musician. Its most remarkable characteristic consists in its being less reedy in tone, and partaking nearly of the quality of the harmonic sounds of stringed and wind instruments. The change produced in the voice when passing from the falsetto into the common tone, or the reverse, is in some persons very sensible to the ear, whilst in others it is almost imperceptible. Some individuals, moreover, have the faculty of producing in the same pitch as many as eight or ten tones, possessing either the falsetto or the common character. The falsetto has been generally ascribed to some particular adaptation of the upper ligaments of the larynx. Dodart * has attempted to prove that it is a supra-laryngeal function, and that the nose becomes the principal tube of sound instead of the cavity of the mouth. Bennati + also considered these tones as being modulated by the supra-laryngeal cavity alone. This hypothesis, however, is untenable, since it supposes the column of air not to be influenced by the trachea, which is contrary to experience. In order to detect some of the movements of the larynx while the voice is passing from the first to the second, or falsetto register, it is only necessary to place the point of the finger in the crico-thyroid chink, when it is found that at the moment the transition from the primary to the secondary register takes place, this chink, which was closed during the production of the highest note of t he ordinary register, suddenly opens on the production of the first note of the falsetto register, and consequently the thyro-arytenoid ligaments are relaxed at the same moment the\n* M\u00e9m. de l\u2019Acad. 1707.\nj- Recherches sur le Mechanisme de la Yoix humaine.","page":1483},{"file":"p1484.txt","language":"en","ocr_en":"1484\nVOICE.\nlarynx falls, and the vocal tube is lengthened, although during these changes the tones become more acute. \u00c4s soon as this has taken place, the larynx again rises as the voice becomes more acute. In a mezzo-soprano voice endowed with a double falsetto, or third register consisting of several tones of each register, with the power of producing tones of the same pitch either of the ordinary or the falsetto quality, we observed that the larynx fell at the commencement of each register, and that the thyro-arytenoid ligaments were twice relaxed, but in a much smaller degree. These observation have since been verified by many musical persons.\nIn order to explain the phenomena as connected with the production of falsetto tones, we must remember that at the highest note of the primary register the crico-th\\ roid muscles are contracted as much as possible in closing the crico-thyroid chink, and therefore that no further tension of the vocal cords can take place. In this state of things, the thyroarytenoid muscles are at their maximum of elongation, and their transverse section is a minimum; consequently neither can a higher note be produced by an extension of the ligaments, nor are these muscles in a condition to affect the dimensions of the glottis ; hence the necessity of some alteration in the state of the larynx in order to effect the scale of the falsetto, which is an octave above the ordinary register, and to prevent the mere repetition of the same series of sounds. This alteration might be produced in two ways ; one of these is a partial closing of the aperture of the glottis caused by the action of the thyro-arytenoid muscles when they have returned to their ordinary condition, and are in a favourable state to produce that effect under the influence of the laryngeal nerves. For, let us suppose the larynx to be in the same state as at the commencement of the primary register, except that the chink of the glottis is half c\u2019osed ; the consequence will be that as only half the length of the ligaments can be made to vibrate, the octave of the lowest note in that register will result from the same tension which produced that note, and this will manifestly be repeated in consecutive notes of the range of the falsetto. This range is limited in general to a few notes, owing probably to the chink being soon completely closed by the stretching of the vocal cords. It is also owing to this partial closing of the glottis that a much less quantity of air is required for the falsetto than for the ordinary scale, which is proved by our being able to sustain a given note in the falsetto to a much longer time than we can sustain the corresponding note in the primary register. The partial closing of the glottis was observed by Majendie in his experiments on the dog, and by Mayo in the human subject. Another explanation was suggested by Gottfried Weber, namely, that the falsetto range is caused by a nodal division of the vocal cords producing harmonics of the fundamental notes, by which means the glottis acquires the same pitch as if it were half closed. If we consider\nthe glottis as a reed, it is evident that since the number of vibrations must in this case be the same for the same note as when we suppose the ligaments to obey the laws of cords, the axis of vibration or the breadth of the ligament must be duly diminished, which may be brought about by the rotation of the thyroarytenoid muscle on its axis.\nHaving thus considered how the glottis may act in the falsetto range, let us now examine in what way the vocal tube contributes to its formation. We have seen that this tube gradually shortens during the ascent of the primary register, suddenly falls to its original length when the falsetto commences, and again diminishes during the secondary register. Now it appears from Savart\u2019s experiments that, notwithstanding the shortness of this tube, the wave length of a column of air vibrating within it is the same as that of a rigid pipe of much greater length, and we have therefore strong grounds for believing that the notes of the primary register are reinforced in consequence of the vibrations of the glottis being always in unison with the fundamental pitch of the walls of the tube ; hence in the falsetto, when the vocal apparatus has resumed its original condition, there will be less reinforce ment of the sound, since the parietes of the vocal pipe are no longer in unison with the glottis, but give its grave octaves. We have found, by numerous experiments, that a flexible disc will vibrate to almost any pitch, but will reinforce the sound in a trifling degree only, unless the pitch be in unison with its fundamental note ; and on the same principle we may suppose the intensity of the notes in the second register tobe diminished, and their quality to be modified by the forced vibration of the walls of the tube, while in the primary all things concur in augmenting the effects produced by the glottis. Muller agrees with Lehfeldt in opinion, that the falsetto notes are produced by the vibrations of the inner portion of the borders of the vocal ligaments, and the variation of the pitch by their tension ; and, although he does not mention by what mechanism this is effected, he seems to attribute it chiefly to the agency of the thyroarytenoid muscles. The author\u2019s explanation is in many points coincident with that of Miiller, but he has taken into account one or two circumstances which appear to have escaped Muller\u2019s attention. The natural key or pitch of the vocal organs may be found by sounding the voice, without either elevating or depressing the larynx. The grave octave of that note will be the fundamental sound of the vocal ligaments vibrating in their m< st relaxed state, with the glottis entirely open. Any tones of a graver pitch, produced by an unusually relaxed state of the vocal cords, lose both their quality and intensity, and cannot be included in the compass natural to the voice. According to the preceding principles, the pitch of the voice being usually an octave, or a fifth graver than the length of a column of air within the vocal pipe, we see the cause why a falsetto quality of sound cannot be","page":1484},{"file":"p1485.txt","language":"en","ocr_en":"1485\nVOICE.\nobtained except during the production of acute tones. In many persons the speaking pitch is an entire octave graver than corresponds to the length of a tube, which would enable a column of air to produce the same sound ; and in such persons the falsetto can seldom be effected. In consequence of the pitch of the vocal organs thus occupying a middle or central position between the acute and grave notes, a great facility is afforded to their action in modulating the voice. The vocal tube, like any other tube open at both ends, is said to be capable of producing the harmonics of its fundamental tone in the ratio of the series of natural numbers, 1, 2, 3,4. These harmonic sounds have been described by Knecht of Leipsic, and by Dr. Young. I have occasionally thought that I have heard them during the forcible expiration which attends the boisterous laughter of children. The density of the air inspired is said to affect the pitch of the voice as in rigid tubes.\nThe influence of the epiglottis on the voice has been the subject of divers hypotheses. MM. Biot, Majendie, and Mayo have inferred, from the experiments of Greni\u00e9, that the epiglottis prevents the tones from becoming more acute when they increase in intensity. Lis-covius, on the other hand, states that neither its depression, elevation, nor even its entire removal has any effect on the voice.* Haller appears to have deduced the same opinion from the circumstance of birds being destitute of this organ. \u201c Epiglottis equidem nihil facit ad vocem, cum ea (vox) nata sit et perfecta quamprimum aer ex glottidis rima prodit, et absque epiglottide aves suavissime canant.\u201dj' According to Muller, the influence of this organ on the pitch of the voice is exercised during its depression only, rendering the tones graver, and at the same time duller. He thinks we evidently employ it in this way during the production of very deep tones ; and observes\nthat, by introducing the finger at the side of the mouth, the epiglottis will be found to maintain the same position during the utterance of musical notes, whether they be of the falsetto character, or of the ordinary scale. I am disposed to ascribe to the functions of the epiglottis much the same value as Miiller ; since it is clear that its presence is not essential to the mere formation of voice, for it may be removed, together with the superior ligaments of the glottis, the ventricles of the larynx, and the capitula laryngis of Santorini, without impeding the vibratory movements of the glottis.\nThe art of singing consists in the application of the vocal organs to produce a certain succession of tones in some determinate order, which constitutes melody. This can be accomplished with precision by those only who can accurately discern with the ear, and imitate with the voice, the variations of the pitch of a musical instrument, or other sounding body. In many persons the perception of sound is defective ; so that, whatever may be the purity and intensity of their notes as single unconnected musical sounds, they can never be used for musical purposes, that is, for sounds succeeding each other at regular intervals, governed by fixed rules. Many persons can imitate the voices of birds and beasts, and diversify the character of their tones to an indefinite extent. These performances illustrate the perfection of the human voice, but the artifices by which they are effected have no reference to the subject under investigation. The musical varieties of the human voice are classed according to their pitch, or the middle note of their primary register, which depends on the dimensions and physical constitution of the vocal ligaments. These varieties are, the Bass, the Tenor, the Contralto, and the Soprano * ; the usual compass of each kind in the adult is represented in the annexed table.\n__________!_________________________I\nI Contralto.\t] Soprano.\nCDEFGABC'D\u2018E'F' G' A>B' C2 D2 E2 F2 G2 A2 B2 C3 D3 E3 F\u00bb G3 A3 B3 C3\nI BaSS- 1________________________! Tenor. I\nI \nIn addition to these characteristic and principal divisions of the voice, there are certain others, called the Baritone, the Mezzo-soprano, and the Soprano-sfogato, which are subdivisions of the foregoing, and the place of either of which in the scale is indicated by its name. We see by this table what an extensive variety of harmonious sounds may be produced by the combinations of the different kinds of voice. In ordinary singers the range seldom exceeds two octaves, except in those endowed with a falsetto. There have been some celebrated singers, such as Catalani, Malibran, and others, whose compass has even exceeded three octaves, but such instances are rare. The\n* Theorie der Stimme. Leips. 1814.\nf Physiology, lib. ix. p. 372.\nvoices in both male and female are nearly of the same pitch until the age of puberty, at which period the voice of males sinks an octave. This change of pitch is owing to a sudden enlargement of the larynx, the anteroposterior diameter of which is augmented by from one-fourth to one-third, with a simultaneous lengthening of the vocal ligaments. During this process the voice is hoarse, and there is a temporary inability to regulate it. Eunuchs do not undergo this change. Ben-nati is of opinion that the voice should not be\n* The first two of these belong to the male sex, and the last two to the female. In this table C is the pitch of the 8-feet organ pipe, or the fundamental of the fourth string of the vi\u00f6loncello ; the ciphers denote the octaves, that is, C1, C2, &c. are the first and second octave of C.","page":1485},{"file":"p1486.txt","language":"en","ocr_en":"VOICE,\n1486\nexercised at this time of life, and in support of his views he cited the cases of Donzelli and Donizetti, of whom the latter lost his voice by singing, whilst the former retained it by abstaining from singmg at that period. There are, however, many examples of persons possessing fine voices, who never paid the least attention to this rule.\nThe oral, nasal, and pharyngeal cavities exercise an important influence on the quality of sounds after their production by the larynx. Further effects are ascribed by Bennati to the arches of the palate, the uvula, and velum, all of which appear to contract with the acute, and relax with the grave tones, and are in constant motion during the modulation of the voice. The contraction of these parts during the production of acute sounds has also been observed by Fabricius ab Aquapendente, Meyer, Gerdy, and Dzondi. Bennati conceived, as has been already mentioned, that the falsetto notes, which he calls notes \u201c sur-laryngiennes,\u201d are produced exclusively in the superior part of the vocal tube ; but it has been shown that this hypothesis is contrary to acoustic principles, and that the same motions of the palate are also equally observable during the production of acute tones of the ordinary register. M\u00fcller also states that the arches of the palate may be touched by the finger without altering the pitch, which could not be the case on the hypothesis of Bennati. It is to be remarked that neither M\u00fcller nor Bennati mentions the opening of the crico-thyroid chink on sounding the first note in the falsetto register; neither do they mention the simultaneous falling of the larynx, and they deny the existence of a third register. According to the hypothesis of Lehfeldt and M\u00fcller, any increased intensity of vocal sound ought to raise the pitch of the voice ; but if this were the case, the performance of prolonged vocal sounds on the same notq, but of variable intensity, would be rendered impossible without a simultaneous adjustment between the tension of the vocal ligaments and the current of air ; whereas, by examining the state of the cricothyroid chink during the utterance of these sounds, it is found that no such adjustment takes place. The exquisite quality of the sounds of the larynx, when modified by the oral and nasal cavities, renders the human voice far superior to any artificial musical instrument ; since its tones glide through all the en-harmonic intervals between successive notes, an effect which no such instrument can perfectly imitate. Dodart estimates the number of tones which can be produced by the voice and appreciated by the ear in the compass of an octave, at three hundred : a striking proof of the complete control exercised by the laryngeal nerves over the vocal apparatus.\nThe'action of the vocal organs in producing speech is a distinct branch of the physiology of voice, which the author has elsewhere investigated.* It is well known that the vowel sounds have been imitated by Kratzenstein,\n* Vide \u00ab On Articulate Sounds, and on the Causes and Cure of Impediments of Speech. London. 1851.\nDe Kempelen, and Willis, by means of mechanism, and that the principles on which they depend have been successfully analysed by the latter : but this is a subject which would require a very lengthened examination to render it the justice which its importance demands.\nHaving now completed the investigation of the physiological character of the human organs of voice, and having for the sake of simplicity considered them in three distinct lights, namely, as membranous ligaments obeying the laws of musical strings, as a reeded instrument, and as a membranous pipe with a column of air vibrating within it, the results of the various experiments which have been noticed would certainly seem to warrant the conclusion that each of these views is correct ; for it cannot be denied that these experiments clearly show the vocal apparatus to be influenced by the air expelled from the chest in precisely the same way as if it were a stretched cord, a reed, or a vibrating tube. Why then should we hesitate to adopt the obvious conclusion that the vocal organs do in fact combine the properties of these various instruments, and are themselves the perfect types of which these instruments are only imperfect imitations ? The error of those who have preceded the author in this inquiry seems to consist in viewing the organs of voice, not as a complex, but as a simple apparatus ; with some the favourite hypothesis has accordingly been that of musical strings, with others that of a reed, while experiments are equally in favour of both.\nIt cannot be expected that in this brief treatise, a subject, wherein, notwithstanding the attention hitherto bestowed on it for many years by men of the highest philosophical talent, so little comparatively has been effected, should be at once exhausted, and all its difficulties removed ; but the inductive method, the only satisfactory mode of reasoning on such subjects, has been most scrupulously pursued; and whatever explanations have been offered of the phenomena of the voice are at least founded on facts which are incontro-vertibly established.\nComparative Anatomy and Physiology of the Organs of Voice. \u2014 Having given an outline of the structure and functions of the vocal organs in man, and stated our views of the principles on which the production of voice depends, we shall now proceed to the investigation of the physiology of voice in the lower animals.\nMammalia. \u2014 In the various orders of mammalia the organs of voice present different grades of development and complexity of structure, producing in each case some peculiarity of timbre, or quality of tone, by which we are enabled to distinguish them from one another. Some species are mute, such as the giraffe, armadillo, and others, whilst some possess voices of greater or less intensity.\nThe organs of voice in the lower mammalia, as well as in man, are composed of lungs, which, considered in an acoustic point of view, act","page":1486},{"file":"p1487.txt","language":"en","ocr_en":"1487\nVOICE.\nmerely as bellows, the trachea or pipe, and the larynx* * * \u00a7 or reed. The nervous and muscular systems are similar to those of man, and do not require to be treated in detail. The acoustic principles of the first section will generally be applicable to the lower orders of Mammalia, so that when the structure is given the functions will be understood.\nIn the account of the anatomy of the vocal organs given by Cuvier, Vicq d\u2019Azyr, Brandt, Wolff, Henl\u00e9, and others, no estimate is made of the relative dimensions of the larynx in the various classes of animals ; therefore, in order that the reader may form an idea of their magnitude in Mammalia, compared with that of man,f it will only be necessary, in those which have a similarity of figure, to give the linear value of one of their dimensions, namely, that of the mean height of the superior margin of the thyroid, above the plane of the base of the cricoid, since their respective magnitudes will be as the cubes of those heights.^ Also the lengths of the inferior thyro-arytenoid ligaments, when devoid of tension, are given. The letters H and L will be used to represent the heights and lengths respectively.\nQuadrumana.\u2014The vocal organs of the Quadrumana have already engaged the attention of several distinguished anatomists, such as Vicq d\u2019Azyr, Camper, Hunter, Cuvier, Brandt, and others ; and a condensed view of this part of the subject will be now given.\nChimpanzee. \u2014 Os hyoides : base concave, where a sac b {fig. 894) is lodged. Larynx, H. 0'8 in. Thyroid : margins, superior and inferior, nearly parallel. Cornua short ; superior inclined upwards and backwards, inferior inclined downwards and forwards. Cricoid elliptical : margins, superior triangular, notch in front; inferior parallel to the first ring of the trachea, except in front, where it is depressed. Arytenoids small. Cuneiform curved, and in contact with the anterior margin of the arytenoids. Cart. Santorini \u2014 inferior thyro-arytenoid ligaments prominent. L. 0\u20185 in. to 0'6 in., superior thyro-arytenoid ligament not prominent. Ventricles of Morgagni oval, deep, leading to sac (a, a), lying between the epiglottis and arytenoid cartilage ; right sac anterior to the left, convoluted, terminating in the concavity of os hyoides (c). Epiglottis : apex obtuse, trachea 16 rings. Voice more acute than in women ; quality inferior: cause, sacculated larynx, &c.*\n* In the following description, the axis of the vocal tube is supposed to he perpendicular to the horizon, and not parallel or oblique, as is generally the case in the living animal.\nf In man, we may assume the mean of Ill\u2019S in. and L\u2014072834.\nJ In most Mammalia the figures of the larynges are similar ; but in some orders they are dissimilar. For instance, in the Cervus, amongst the Ruminantia, the thyroid bulges out considerably in front, and in the Sus scrofa, amongst the Pachy dermata, it is extremely narrow. In the Cetacea the whole larynx differs from those of all the other orders.\n\u00a7 These measures relate to an animal not quite full grown, and are rather too small for an adult chimpanzee.\nOrang-outang. \u2014 Larynx : volume equal to chimpanzee. Thyroid : wings united at an obtuse angle : margins, superior notched in mesial line. Cornua short. Cricoid elliptical : margins, superior and inferior, depressed in front ; the latter connected with the first ring of the trachea. Crico-thyroid chink large. Arytenoids small. Cuneiform large and curved. Cart. Santorini : vocal ligaments,\nFig. 894.\nLateral view of the Larynx of the Chimpanzee, a, a, sac connected with the lateral ventricles ; h,\nos hyoides ; c, sac protruding at the base of os\nhyoides ; d, thyroid ; e, trachea ; f cricoid.\ninferior prominent ; L. less than in woman. Ventricles oval, furnished with a canal penetrating the thyro-hyoid membrane. 'Sacs large, lie on each side the larynx. Ventricles valvular, rendering the inflation of the sacs under the control of the animal. Epiglottis broad, apex obtuse.*\nGibbons.\u2014Os hyoides : base not excavated. Larynx, volume nearly equal that in orang; ventricles deep, communicating with a sac in Hylobates agilis, which lies in front on the thyro-hyoid membrane. Voice acute. Cry, bow wow.\nMonkeys of the old continent.\u2014Os hyoides : base excavated (fig. 895,b). Sim. Hamadryas, larynx destitute of sac.f Larynges perforated, sacs in the thyro-hyoid space. S. cynoc\u00e9phales, S. mona, S.cercopithecus(y%.895,A), S.Malbrouch, S.\u00c6thiops, S. rubra, S.Veter J,\n* According to Camper, the laryngeal sacs in the orangs disqualify them from applying the vocal organs to the use of articulate language ; but this hypothesis is untenable, because language is independent of the quality, intensity, or pitch of the laryngeal sounds.\nf Cuvier states that S. Patras has no sac or aperture in the larynx ; this is, however, an error.\nX Cuvier.","page":1487},{"file":"p1488.txt","language":"en","ocr_en":"U88\tVOICE.\nand S. Inuus *, two sacs. Laryngeal aperture situated at the base of the epiglottis, oval or circular. Voice acute ; quality hoarse : cause, laryngeal sacs.\nFig. 895.\nA\na\nLarynx of S. Cercopiihecus.\nA. a, epiglottis ; b, os hyoides ; c, sac ; e, trachea. b. f, cavity of the os hyoides.\nAlbino Baboon. \u2014 Os hyoides : base, b (fig. 896.) excavated, inclosing a sac, c; Larynx : H. *75 in.; Thyroid : upper margin concave, lower irregular ; Cricoid : a vertical\nFig. 896.\nLarynx of an Albino Baboon, b, section of the os hyoides, showing the inclosed sac c ; d, thyroid ; /, crico-thyroid space ; e, trachea.\nridge rising from the posterior surface, the cartilage tapering towards the anterior surface * Ludwig.\nwhich is very narrow; Crico thyroid space: large ; Epiglottis : apex obtuse.\nIn the monkeys of America, some species have sacs appended to the larynx, the most complicated form of which is observed in\nSimla Senicuius, or Red Howling Monkey.\u2014 Os hyoides, base excavated ; opening quadrangular. Thyroid, volume three times that of man * Cricoid elliptical, nearly osseous. Pomum large and excavated, into which pris-matico-oval sacs open ; sacs also communicating with the larynx by a semilunar opening at the base of the epiglottis. Arytenoids small. Cuneiform absent ; instead of them, prominence.f Vocal ligaments: superior imbedded in tendino-cartilaginous masses inferior inserted at base of pomum. Ventricles passing on each side of epiglottis, which is connected with an infundibuliform sac, pomum, and oval pharyngo-laryngeal sacs.\u00ff Voice intense; howl discordant.\nS. Appell a and S. Capucina. \u2014 Os hyoides not excavated. Thyroid, cricoid, and arytenoid, like man. Cart. Santorini large, and curved backwards. Cuneiform absent ; their place supplied by fatty tendino-cartilaginous masses meeting each other to form a channel for the passage of air : in shape like the letter S. || Voice: quality like a flute, hence called Whistling Apes ; expression, a plaintive melody, from which they are also called Weeping Apes.\nS. Rosalia. Larynx perforated at the thyro-cricoid ligament, below the thyro-aryte-noid ligament ; aperture circular, sac small.\nS. Coaita. Larynx like the Sapajous. Trachea dilated behind the cricoid cartilage.\nS. Ateles arachno\u00efdes.\u2014Os hyoides : base quadrangular, excavated. Larynx: cariilages of Santorini with masses substituted for cuneiform cartilage. Vocal ligaments : superior give rise to the cuneiform masses ; inferior lie over the superior \u00ce at their insertion.** Epiglottis: apex notched and connected with the cuneiform fibro-cartilaginous masses. Voice acute ; quality hoarse ; melody, a plaintive cry.\nLemur. L. gracilis. \u2014 Os hyoides : base not excavated. Larynx : no sac. H. U'33 in. Thyroid : wings united at an obtuse angle ; margins, superior oblique, inferior parallel to superior. Cricoid elliptical ; margins, superior and inferior depressed. Crico-thyroid : chink large, rhomboidal. Epiglottis rounded ; at its base a pit. L. 0\u2018133 in.\nL. tardigradus. Cornua elongated and united with first ring of trachea.-f-f In Lem. Mongoz and L. Catta are processes running from the epiglottis to os hyoides. Voice in Mongoz, a peevish kind of cry when irritated.\nCheiroptera. Phyllostoma Spectrum.\u2014Os hyoides like that of Lemurs. Larynx : H. 0-5 in. Thyroid like the Lemurs ; notch, superior absent; prominence small; margins,\n* Brandt.\tt \u00efbid-\t\u00ce Ibid-\n\u00a7 Humboldt describes six laryngeal sacs. Camper one. Vicq. d\u2019Azyr, Cuvier, and Brandt more than one.\n|| Cuvier. Brandt.\t1 Cuvier.\n** Brandt.\ttt Ibid-","page":1488},{"file":"p1489.txt","language":"en","ocr_en":"VOICE.\t1489\ninferior a notch ascending to middle of carti- row. * L. 0*2 in. Ventricles short. Epi-\n.ge. Cricoid like that of Lemurs ; margins, notch in front, and a foramen on the right\nMg. 897.\nLarynx of S. \u00c6thiops.\nd, tongue ; b, epiglottis ; c, opening to sac ; e, superior vocal cords ; f, inferior vocal cords ; a, ventricles of Morgagni ; g, a vertical furrow ; h, trachea.\nside. Arytenoids as in L. Mongoz. Cuneiform cart, absent. Sesamoid oblong b (fig. 898). C. of Santorini triangular. Interarticular cart.\nFig. 898.\nPosterior view of the Larynx of the Phyllostoma Spectrum.\na, epiglottis ; b, sesamoid ; d, junction of the cart, of Santorini ; f interarticular cart.; g, raised margins of cricoid cart. ; c, surface of cricoid ; e, trachea.\nsize of a millet seed, oblong (/). Vocal ligaments : superior not prominent ; inferior nar-VOL. TV.\nglottisf rounded, with pointed projection on each side. Voice very acute, with a plaintive cry. Trachea 34 rings.\nInsectivora. Erinaceus Europ\u0153us.\u2014Larynx : H. 0*45 in. Thyroid : wings united in a short point. Cricoid a posterior vertical furrow c [fig.899). Crico-thyroid : chink triangular. Epiglottis : apex acute ; base divided by a fissure into two lobes, into which the vocal ligaments are inserted. Cart, of Santorini inclined forwards, having the interarticular cart. J: between them b. Vocal ligaments : inferior strong. L. 0-176. Ventricles deep, leading to a sac \u00a7 situated between the epiglottis and os hyoides. Voice generally mute.\nFig. 899.\nLarynx of Erinacea Europ\u0153a. a, epiglottis ; b, prominences of cartilages of Santorini; f interarticular cartilage; c, furrow of cricoid cart.\nCarnivora. Ursus Malayanus. Larynx : H. 1*55. Thyroid : wings unite at an obtuse angle; tubercle in mesial plane a [fig. 900), to which the epiglottis is attached ; margins, superior ascending upwards, inferior excavated in front as far as the tubercles b (fig. 900). Cornua : superior short ; inferior very long. Cricoid : superior margin inclined upwards, with a notch in front, by which the body is nearly cut through ; inferior concave in front ; lateral parietes held together by a transverse ligament. Arytenoids rhomboidal, between which are the sesamoids, d d, furnished with small muscles to approximate them. Cart. Cuneiform and C. Santorini present. || Epiglottis broad ; apex obtuse. Vocal ligaments : inferior inclined upwards to the place of the superior, separated by a transverse groove. L. 0-833, or nearly equal those of man.\nUrsus Arctos. See Wolff.\nSyriac Bear. See Brandt.\nViverra Nasua. \u2014 Thyroid : wings united at an obtuse angle. Cricoid semitransparent.\n* Vicq. d\u2019Azyr states that the vocal ligaments are absent, but this is denied by Brandt.\nf He is also in error in stating that the epiglottis is absent in the common bat.\nX Brandt thinks that the interarticular cart, of Mammalia is represented by the Cricoid of Birds ; but, as Heule observes, there seems to be little foundation for this opinion.\n\u00a7 Wolff.\n|| These cartilages have been confounded with each other by Cuvier and Wolff.\n5 c","page":1489},{"file":"p1490.txt","language":"en","ocr_en":"1490\nVOICE.\nEpiglottis broad. L. 0375 in. Voice more acute than in woman.\nMeles Europ\u0153a.\u2014Thyroid: margins notched in front. Crico-thyroid chink triangular, Ary-\nFig. 900.\nAnterior view of the Larynx of Ursus Malayanus.\na, tubercle ; b, notch of thyroid cart. ; c, notch of cricoid cart.\nShowing the Sesamoid Cart, d d, of Ursus Malayanus.\ntenoids small. Epiglottis triangular. Ventricles deep, leading to two sacs, one of which lies under the root of the tongue, the other between the thyroid and cricoid cartilages.*\nMustela Furo. See Wolff. Ventricles lead to sacs.\nLuira Vulgaris. \u2014 Thyroid : superior and inferior margins parallel and inclined upwards, superior terminating in a round apex, inferior hollowed out in front b {fig. 901.), and protuberant ; Cricoid, (c) inferior margin, so widely separated in front, as only to be slightly united at the inferior margin of the thyroid.\n* Cuvier was of opinion that the posterior part of the vocal ligaments produced the vocal sounds.\nEpiglottis, oval but not large. Cart, of Santorini absent.\nFig 901.\ntf,\nOblique view of the Larynx of Lutra Vulgaris, a, epiglottis ; b, thyroid ; c, c, cricoid.\nCanis familiaris. Thyroid : margins inclined upwards ; wings unite at an obtuse angle. Cornua : superior furnished with a transverse ligament running to the thyroid as in the hyaena. Cricoid : superior margin depressed in front. Arytenoids curved, and inclined from each other. Cart. Santorini and C. Cuneiform present. Ventricles deep. Epiglottis triangular, having a vertical furrow at its base. L. (and consequently the pitch of the voice) varies in almost every species; modulation expressive of emotion.\nFelis Leo.\u2014Larynx : H. 3T4 in. Thyroid : margins parallel, and inclined forwards and upwards ; wings united at an obtuse angle ; notch large below the pomum. Cricoid elliptical, ridge of Galen prominent. Cricothyroid : space large, rhomboidal, traversed in front by muscular fibres. Arytenoids rhomboidal. Cart. Santorini absent. Vocal ligaments : superior prominent. Ventricles deep, forming a sac between the vocal ligaments. Epiglottis : apex obtuse. Trachea 50 rings.* Voice grave, very intense ; roar terrific.\nF. Tigris. \u2014 H. 1-8 in. L. 1 in. The superior ligament very prominent. In other respects the larynx resembles that of the lion. Voice more acute than the lion. Purrs like the cat.\nF. Ijeopardus and Catus. \u2014 Larynges differ only in magnitude. The whole of the Feline order are remarkable for the prominence of the superior ligaments, by which the purring is most probably produced. c {fig. 902.)f Voice a mewing, wrhich is well known ; also a melancholy cry by night.\n* Vicq. D\u2019Azyr and Cuvier state that the rings of the trachea are not entire. Perrault, on the contrary, describes them to be complete circles; but this is an error.\nf Vicq. d\u2019Azyr ascribed the purring of the cat to two thin membranes situated beneath the inferior ligaments ; but we were unable to detect them : nor could Cuvier, Wolff, Casserius, and others, succeed in finding them.","page":1490},{"file":"p1491.txt","language":"en","ocr_en":"VOICE.\t1491\nPhoca vitulma, or Common Seal.\u2014Larynx : H. 1*2 in. Thyroid : wings united by a small cartilaginous plate ; cornua parallel to axis of\nFig. 902.\nLarynx, Tongue, and Trachea of the Cat. a, tongue ; b, epiglottis ; c, superior vocal cords ; d, infinferior vocal cords.\nvocal tube. Cricoid : depth of anterior to posterior surface as 2 to 5. Crico-thyroid chink rhomboidal. Epiglottis triangular, fixed to the thyroid by cartilage. L. 0\u2019675 in. Trachea 78 rings.* Voice, nearly the pitch of a soprano; melody, a melancholy moaning.\n* According to Wolff, the first twelve rings are complete circles, the rest overlap each other.\nMarsupialia. Kangaroo.\u2014Thyroid: margins, superior a notch in front. Arytenoids large. Cuneiform Cart., ventricles and superior ligament absent. Vocal cords membranous, fold upon themselves, so that they cannot be stretched* by the arytenoids. Voice, when in pain, moans piteously, f Phalanger.X \u2014Vocal cords: membranes substituted for vocal ligaments, but, as in the kangaroo, do not fold on themselves. Common Phalanger : vocal ligaments absent.\nDidelphis Opossum.\u2014( Fig. 903.) Larynx : H. 0f288in. Superior ligament absent. Ventricles\nFig. 903.\n1. 2.\n1. A lateral view of the Larynx of Didelphis Opossum.\na, thvroid cart.; b, cricoid; c, crico-thyroid ligament ; d, trachea.\n2. A posterior view of the same, c, cricoid cart. ; e, laryngo-tracheal ligament ; d, trachea.\nvery small. Inferior ligament : L. 0T76 in. Voice consequently acute; purrs like the cat. \u00a7 Trachea 20 rings.\nRodent IA. Paca.\u2014Epiglottis nearly semicircular ; at its base a blind sac. Ventricles not deep. Vocal cords but little salient.\nCavia capybara. Larynx similar to that of the paca. Voice grunts like a pig.\nLepus cuniculus. The Rabbit. \u2014 (Fig. 904.) Larynx: H. 04 in. Thyroid: wings united at an obtuse angle; margins oblique and parallel. Crico-thyroid chink large. Arytenoids small, pyramidal. Cuneiform cart, curved. Vocal cords: superior thin and delicate ; inferior prominent. L. 0\u201926 in. Epiglottis a obtuse ; apex slightly notched, at the base of which are 4 conical cartilaginous bodies or tubercles inclined towards each other : between them, b b, is a triangular space ; and a vertical groove passes between the insertion of the vocal ligaments from b to c. On each side a ligamentous filament descends, which acts on the tubercles above mentioned. The inferior tubercles give attachments to superior vocal ligaments and roof of the ventricles. Office of tubercles\u2014to open the ventricles, stretch the superior ligaments, and give free-\n* Cuvier.\nf Bennett\u2019s Wanderings in New South Wales.\nt The Phalanger of Cook.\n\u00a7 Cuvier describes two small vibrating membranes at the base of the epiglottis, which is denied","page":1491},{"file":"p1492.txt","language":"en","ocr_en":"1492\nVOICE.\ndom of motion to inferior ligaments. Voice acute.\nFig. 904.\nI.\t2.\nbases fixed to the arytenoids. L. 2 in. Superior vocal ligaments not prominent. Ventricles of Morgagni oval, deep, cc(fig. 906) Epiglottis\nFig. 905.\n2. Side view of the same, externally, a, epiglottis ; b, thyroid; d, cricoid; c, crico-thy-roid ligament ; e, trachea.\nHystrix ci'istata. Porcupine.\u2014Vocal ligaments absent. Ventricles of Morgagni none. Voice mute.\nCastor Fiber. The Beaver.\u2014Larynx : H. 0*45 in. Epiglottis triangular, having a vertical raphe upon its posterior surface terminating in a sac bordered by the vocal ligaments. Arytenoids small and conical. Vocal cords : L. 0 25 in. Trachea 22 rings. Voice acute.\nMus Rati us.\tSee details by Wolff.\nEdentata. Ornithorynchus paradoxus.\u2014 {Fig. 905.) Larynx : H. -6 in. Thyroid : wings united at an obtuse angle ; body partly cartilaginous, and partly osseous ; supports laterally two transverse osseous processes f f at the bases of which are two curved cartilaginous appendices. Cricoid elliptical. Arytenoid triangular. Ventricles not deep. A sulcus, d d, lies between superior ligament and cricoid cartilage.* Epiglottis : apex acute, a. Trachea 15 rings.\nArmadillo.\u2014Epiglottis bilobed. Voice mute.\nBradypus tridactylus or Sloth.\u2014 Larynx : Cart, of Santorini and superior vocal cords absent. Ventricles a mere impression. Inferior vocal ligaments free. Trachea convoluted. Voice a plaintive melody, consisting of an ascending and descending scale of the hexa-chord.f\nPachydermata. Equus.\u2014H. 1-85. Thyroid: wings united at an acute angle, and notched below to the pomum. Cricoid : margins, superior deflected inwards. Crico-thy-roid chink inclined both vertically and horizontally. Arytenoids large; bases deflected from each other, by which the glottis is always kept open. Cart, of Santorini curved or hook-like\n* This is described by Blainville, but Meckel seems not to have observed it.\nf Bingley, An. Biog.\nA view of the internal mechanism of the Larynx oj Ornithorynchus paradoxus, a, epiglottis; b, superior vocal cords; c, inferior vocal cords ; d, sulcus ; f, -transverse osseous processes; g, spines of transverse processes; e, trachea.\ntriangular, a; at the base two processes* connect it with the arytenoids. Between the commissure of vocal ligaments and epiglottis there is an oval cavity, c ; and on the posterior surface of the epiglottis a groove, furnished at its base with a semilunar membrane.\\ Trachea 52 rings. Voice, the neigh, which is well known, but not easily described. Herrissant has exaggerated, as Cuvier states, the office of the semilunar membrane in the production of this singular sound.\nAsinus vulgaris.\u2014Larynx : H. P95 in. Thyroid : wings united at an obtuse angle. Cricoid elliptical. Crico-thyroid chink not large. Epiglottis : apex obtuse a (fig, 906.) ; at its base an arched cavity, b, in which the vocal ligaments are inserted. On each side of this cavity c, c, are two circular apertures, which lead to two large sacs situated behind the mucous membrane between the vocal ligaments and internal surface of the thyroid. L. 1-275 in. Trachea: rings spiral. Voice: quality discordant; range about 5 tones. The bray is well known. J Mule.\u2014Laryngeal cavities similar to those in the ass. Voice, a species of bray resembling the voice of the ass, rather than that of the horse.\n* These are the horns of the epiglottis of Casserais.\nt The semilunar membrane of Herrissant.\n\u00ce According to Herrissant, the edge of the arched cavity causes the peculiar timbre of the voice of the ass, and acts like the semilunar membrane in the neigh of the horse ; both these hypotheses, however, are extremely doubtful ; the sac mentioned in the text doubtless contributes largely to the production of the braying of the ass. During the bray an acute sound accompanies the inspiratory movement of the thorax.","page":1492},{"file":"p1493.txt","language":"en","ocr_en":"VOICE.\n1493\nQuagga.\u2014Larynx somewhat like the horse,\nMg. 906.\nLarynx of the Horse laid open.\na, epiglottis ; b, semilunar membrane ; c, aperture at the base of the epiglottis ; d, sulcus ; e, ventricles ; f arytenoids ; g, inferior vocal cords ; h, trachea.\nFig. 907.\n7Vie Larynx of the Ass laid open.\na, epiglottis; b, arched cavity; c, apertures; d, arytenoids and vocal cords ; e, trachea.\nbut destitute of semilunar membrane. * Voice resembling the bark of a dog; hence its name.\nTapir Americanus.\u2014Larynx : H. & L. less than in the horse. Thyroid : pomum absent. For the Cart.of Santorini and Cart Cuneiform, are substituted fibro-cartilaginous masses, f Vocal ligaments : superior short and indistinct ; inferior strong. Ventricles elongated into an oval blind sac. A semilunar opening in the base of the epiglottis, leads to a curved cavity on each side of it.J Voice, a species of whistle.;)\nSmscrofa.\u2014Larynx; H. ]*55in. Thyroid: wings united at an acute angle, become more acute below ; superior cornua absent. Cricoid\nMg. 908.\nMesial section of the Larynx of the Pig (Sus scrofa').\na, sac ; b, superior ligament ; c, inferior ligament ; d, sacculus laryngis ; e, left arytenoid c. ; f cricoid c. ; g, trachea.\nan eccentric ellipsoid. Arytenoids locked to each other at the apex of their superior prominence by a cartilage, jj Vocal cords directed obliquely downwards to form, with the axis of the vocal tube, an angle of 30\u00b0, and are inserted at the height of the thyroid from its lower margin. L. 0-9 in. Ventricle d {fig. 908.) an oblong chink leading, by a groove inclined backwards, to a sac, a. Voice a grunting, discordant sound.\nRhinoceros.\u2014 Larynx : H. 5 in. ; Thyroid : cornua none, figure rhomboidal. Cricoid :\n* Cuvier.\tf Brandt.\n\u00ce Brandt.\t\u00a7 Bingley, An. Biog.\n|| This cart, is peculiar to the pig.\nThe larynx of this animal has been described by Casserius, Herrissant, Cuvier, Wolff, and Gurlt ; the former first noticed the sacs in these words, \u2018 Foramina duorum ventrium per qu\u00e6 \u00e4er ingreditur, ad grunnitum in porcis efficiendum.\u201d Herrissant supposed the sacs to he the principal organs in the production of the voice of the pig, hut we cannot concur in this opinion, they merely affect the quality of the sound.\n5 c 3","page":1493},{"file":"p1494.txt","language":"en","ocr_en":"1 494\nVOICE.\nnearly thrice as deep behind as in front ; Cricothyroid space very large ; Ventricles of Morgagni large and deep ; superior vocal cords prominent. L. 1*75 in.\nElephant.\u2014Larynx : H. 4-83 in. Thyroid : wings united at an obtuse angle ; surface externally convex ; cornua, superior short ; margins of inferior notched in front. Pomum a distinct cartilage. Cricoid elliptical ; inferior margin concave ; body deep, posteriorly passing over the first three rings of the trachea. Vocal ligaments : superior indistinct ; inferior strong. L. 375. Trachea, 30 rings, which are often partially subdivided. Voice intense, of a grave pitch, aided by the proboscis.\nRuminantia. Camelus Bactrianus. \u2014 H. 3 in. Thyroid : wings united at an obtuse angle. Cricoid elliptical. Arytenoids triangular. Ventricles oval. Epiglottis : apex\nFig. 909.\nThe Larynx of the Camel laid open.\na, epiglottis; b, superior vocal cords; c, inferior;\nd, arytenoid cartilages ; e, vertical ridge ; h, tubercle ; /, trachea.\nobtuse, posterior surface furnished with a tubercle. Vocal ligaments : superior rather broad bb (Jig. 909); inferior strong cc. L. 1*5 in. Voice grave, but seldom exercised.\nLlama.\u2014Larynx similar to the camel. Vocal ligaments, superior and inferior, present.\nGiraffe.\u2014Vocal ligaments said to be absent.\nBos. \u2014 Larynx: wings of thyroid nearly equilateral, united at an obtuse angle. Cricoid massive, elliptical. Vocal cords : superior absent ; inferior strong. L. 0'85 in. Trachea 52 rings. Voice sonorous, intense, pitched in C = 256 vib. in \\\".\nOvis Ammon.\u2014Larynx differs from Bos only in dimensions. Voice guttural, pitched in F = 341 vib. in l\".\nAntelope. A. Dorcas, and A. Corinna.\u2014Larynx perforated by an aperture at the base of\nthe epiglottis leading to a sac. A. gutlurosa, pomum very large.*\nCervus. C. Farandus or Rein Deer. \u2014 Larynx has a laryngeal opening at the base of the epiglottis -f, leading to a large sac.\nC. Alcas. H. 2'5 in. Thyroid : wings united at an obtuse angle ; cornua long ; pomum large, and concave within. Cricoid : posterior deep, shielding the five first rings of the trachea ; anterior narrow. Crico-thyroid chink c (fig. 910) broad ; crico-thyroid ligament strengthened by additional perpendicular fibres d ; its superior ligament absent, inferior inserted into the concavity of the pomum. L. 1*8 in. Voice grave.\nFig. 910.\nLarynx of Cervus Alcas.\na, thyroid c. ; b, ci'icoid ; d, crico-thyroid ligament.\nC. Capreolus.\u2014Larynx : H. P85 in.\u2014Thyroid : wings united at an obtuse angle. Cornua : superior long, inferior shorter, curved ; pomum large, concave within. Cricoid, eccentric ellipse. Body : posterior deep, anterior narrow. Crico-thyroid chink large. L. 1*26 in. Voice grave.\nCetacea. Ba/cenoptera rostrata.\u2014H. 10 in. Thyroid : wings united at a very obtuse angle %, the superior margins being nearly straight ; inferior excavated by a triangular notch near the centre. Cornua : superior absent ; inferior very large, straight, but curved in the dolphin. Cricoid : deep behind, absent in front, where it opens into a large sac \u00a7\n* See Pallas, Spicil. Zoolog. fasc. xii. fig. 16.\nt See Camper, Naturges. des Orang-outang, &c.\nj Indeed the wings spread open almost into a straight line.\n\u00a7 This sac has been described by Hunter and Sandifoot. In the dolphin and porpoise the cricoid is imperfect in front.","page":1494},{"file":"p1495.txt","language":"en","ocr_en":"VOICE.\n1495\nlying in front of the larynx. Tracheal length 4 in. ; posterior cartilaginous, anterior membranous at its laryngeal extremity. Arytenoids : superior prominences elongated, flattened, and inclined forwards \u2014 their inner margins lie in contact ; the inferior\nFig. 911.\nSection of the Tongue, Pharynx and Larynx of the Porpoise.\na, pyramidal position of larynx ; c, pharynx ; d, laryngeal cavities laid open, and a bristle is passed though the glottis,/.\nprominences short, but strong. Epiglottis : base springs from the superior margin of the thyroid, to which it is fixed by a cartilaginous union. It is flattened and directed backwards to unite with the superior prominence of the arytenoids, with which it completes the aryteno-epiglottic portion of the vocal tube. The diameter of this portion is narrower that! the rest of the tube, which crosses the fauces, enters the posterior nares, and terminates in the olfactory organs. In its passage it is grasped by a strong sphincter muscle of the fauces, as in the porpoise, e e {fig. 911). Vocal ligaments absent. Aperture of the vocal tube, in those which have but one opening, as the spermaceti and bottle-nose whales, grampus, dolphin, and porpoise, \u2022 transverse ; but in those which have two apertures*, as in the great whale-\n* Hunter remarks that the cartilages of the larynx are much smaller in the bottle-nosed whale of twenty-four feet, than in the piked whale of fifteen feet. He is also of opinion that the absence of the Vocal cord, co-existing with that of the thyroid gland, tends to show that the functions of the\nbone whale, it is longitudinal. Thyroid gland absent. Voice absent, or reduced to a single lowing. Trachea, in Balcenoptera ro strata, length 4 in.; posterior cartilaginous, anterior membranous at its laryngeal extremity.\nBirds.\u2014 The vocal organs of birds differ from every other class of animals by the constitution of the superior, and by the addition of an inferior larynx. The same acoustics apply, with few exceptions, to all Mammalia, but in birds is required an additional investigation.\nThe superior larynx of birds is situated immediately below the os-hyoides, to which it is connected by the thyroid membrane, and hyo-aryngeal muscles. Its figure and structure are more uniform than those of the inferior larynx. It is partly cartilaginous, and partly osseous.\nThe thyroid cartilage forms the anterior, and part of the lateral boundary of the larynx, and rests upon the first ring of the trachea. Wings, superior margin ascending forwards and upwards, meet each other in the mesial line, where the cartilage terminates in either a pointed, rounded, or flattened projection; inferior margin usually horizontal, corresponding to the first ring of the trachea, as in Palmipedes, but are excavated in Scansores. The posterior margins terminate in two quadrangular bones, w'ith which the thyroid cartilage is frequently ossified (and these then become portions of the wings of the thyroid ; the quadrilateral bones, being also oblique angled, are shaped to form a union with the posterior margin of the thyroid, and present horizontal edges above and below, leaving a small triangular space for the cricoid cartilage posteriorly. The cricoid is a small triangular bone, lying on the inside of the posterior edges of the two quadrangular bones ; it supports the two arytenoid cartilages, as in Mammalia; and although it forms a very small portion of a ring, it is yet necessary for the completion of it. These four bony or cartilaginous pieces are most distinct in young birds, and amongst old ones are quite distinct in the Anas do-mesticus and Anas mollissimus, but are consolidated into one in the Scansores, ostrich, and many others. The arytenoid cartilages are long and tapering upwards and forwards, and form by their inner margins laterally the rima glottidis : they are generally ossified. Their external margins are bounded by the thyroid cartilage, and their inner margins form the rima glottidis.\nEpiglottis.\u2014 In most birds the epiglottis is situated on the internal surface of the thyroid ; it is rudimentary, and is termed the processus epiglotticus : it is generally osseous, but according to Henl\u00e9 it is leaf-like in the stork and heron ; and in some of the Gallinace\u00e6, as in Sterna,Rallus, and Laras, it is thin, flat, and flexible, as in Mammalia.\nRima glottidis. \u2014 The form of this chink in a state of repose is triangular, the apex being directed backwards : it is bounded an-\nlatter are in some manner associated with those of the former.\n5 c 4","page":1495},{"file":"p1496.txt","language":"en","ocr_en":"1496\nVOICE.\nteriorly by the thyroid, laterally by the arytenoids, and posteriorly by the cricoid cartilage, but is destitute of salient membranous lamin\u00e6. *\nMuscles. \u2014 The superior larynx is raised by the hyo-thyroideus and the thyro-tra-chealis muscles, and depressed by the hypsilo and sterno-trachealis. The glottis is opened by the thyro-arytenoideus posticus, and closed by the thyro-arytenoideus lateralis, as in the higher order of reptiles.\nThe superior larynx is supplied by the superior laryngeal nerve alone, the inferior laryngeal terminating in the inferior larynx and trachea.\nThe inferior larynx. \u2014 This organ is peculiar to birds. It is exceedingly diversified in form and structure. It is always found except in the condor, and other vultures. If we make a section of the lower larynx of birds in the mesial plane, its lateral segments, if viewed separately, present a double organ of sound ; the exceptions to this rule are, the parrot, perroquet, and cockatoo. The inferior larynx of birds is often a very complex structure, and may be considered a double reed furnished with a pipe. It is symmetrical in most orders of birds except the Palmipedes, and is situated between the last ring of the trachea and first of the bronchi; it lies upon the oesophagus posteriorly, where there is generally a triangular space for the passage of that tube.\nThe frame-work of the inferior larynx is formed by the developement of several lower rings of the trachea, which take diversified forms in different orders of birds, and sometimes in the sub-genera of the same order, as in Mergus and Anas among the Palmipedes. In those birds which have a pure quality of voice, and whose instinct excites them to produce a continuous succession of tones, constituting some defined melody, we find the\n* Although anatomists are generally agreed respecting the position and figure of the several pieces which enter into the formation of the superior larynx of birds, they differ widely in reference to the parts which they represent when compared with man. Cuvier conceives that the posterior cartilage, which Humboldt1 calls sockel, represents the cricoid of Mammalia, and that birds are destitute of epiglottis, thyroid, and arytenoid cartilages. Fabricius2 considers it best to divide the pieces into three parts, viz. two arytenoids and an os-innominatum. Tiedemann3 thinks the anterior piece represents the thyroid, the quadrangular pieces the cricoid, and the triangular the arytenoid cartilages of Mammalia. Meckel4, on the contrary, considers the triangular pieces to be the cricoid divided. Carus5 supposes the quadrangular pieces to be arytenoids, and the triangular the cartilages of Santorini. Wagner6 unites the single with the quadrilateral pieces for a cricoid, and the triangular for the arytenoids.\n1 Observations de Zoologie.\n3\tDe Laryng\u00e9. P. i. cap. vii. In op. omnia. Lips. 1687, p. 273.\n5 Zoologie, b. ii. p. 644.\n4\tArchiv, f\u00fcr Anat. und Physiol. 1832, p. 324.\n5\tLehrbuch der Vergleichenden Zootomie, b. i. p. 195.\n6\tLehrbuch der Vergleichenden Anatomie, p. 242.\ninferior larynx not only better adapted to produce a purer quality of tone, but it is provided with a greater number of muscles for modulating the voice.\nAmong the Insessores, the Corvidae and Sylviad\u00e6 have the external walls of the inferior larynx composed on each side of three semilunar bones which are developed from the inferior portion ot the trachea. The larynx is bounded internally by a bone, which traverses the lower end of the trachea, the vertical longitudinal section of which coincides with the plane of the mesial section i {fig. 912); this os transversale, after stretching across the tube, divides at each end into two lamin\u00e6, which diverge laterally from the axis of the bone to meet the two first external bones of the larynx, thus strengthening and completing its solid framework. The superior part of the os transversale is concave, and furnished with a very thin delicate membrane, rising vertically from the bone h {fig. 912): this is called by Savart the membrana semi-lunaris.\ns\tFig. 912.\nSection of the lower Larynx.\nh. membrana semilunaris; i, os transversale; g, membrana tympaniformis.\nThis membrane is most developed in singing birds, and is considered by Savart to be one of the most essential organs of voice in the inferior larynges of the nightingales, thrushes, linnets, finches, and other singing birds, as well as in speaking birds, such as the pies, jays, &c. The inferior edge of the os tratis-versale gives attachment to the membrana tympaniformis.\nBones of the inferior larynx. \u2014 The first bone a (fig. 913) is flattened and curved, being convex externally, and concave internally : it forms the boundary of the internal lateral face of the larynx.\nThe second bone b (fig. 913) presents nearly the same form as the first, but it possesses greater mobility, the muscles which are inserted into it drawing it upwards and out-","page":1496},{"file":"p1497.txt","language":"en","ocr_en":"VOICE.\nJ J 97\nwards perpendicularly to the axis of the bonchus of the same side, by which means the area of the latter is varied.\nThe third bone is but very slightly curved (c). It is separated from the second bone by a triangular membrane ; having its extremities articulated to the second bone by ligaments which permit of an extensive freedom of motion, particularly of a rotatory movement on its axis, and it is an important agent, according to Savart, in modulating the voice. The internal surface of this bone is lined with a fibrous cord which forms the external lip of the glottis. The posterior extremities of these three bones are not united, but have a triangular space between them for the passage of the oesophagus.\nFig. 913.\nInferior Larynx of the Raven,\nShewing the three bones, a, b, c.\nThe Membrana tympaniformis.\u2014 This is a thin transparent membrane, extending from the os transversale to the extremities of the bronchial half-rings g (figs. 912 and 914) : it forms the internal surface of the larynx and bronchi, and is a continuation of the semilunar membrane; so that the tympaniform and semilunar membranes are stretched simultaneously, and the latter is acted upon through the instrumentality of the former.\nThe Arytenoid Cartilage. \u2014 This is a small body situated at the head of the second bone : it is described by Savart as being of a lozenge shape in the starling, but very short in the nightingale. This form of larynx in the Corvidae and Sylviadae is provided with six pairs of muscles.* (See fig. 914.)\nPalmipedes. \u2014 In the genera Anas and Mergus the inferior larynges of the males only are unsymmetrical, and composed of bony cavities. In the Anas domesticus, the inferior larynx presents osseous cavities formed by\n* These muscles are given in detail by Savart, M\u00e9moire sur la Voix des Oiseaux, in the Ann. de Chem, et de Physique, vol. xxxii., also Cuvier, in the R\u00e8gne Animal, vol. iv. There are five pairs of muscles assigned to the inferior larynx of the singing birds by Cuvier, Mr. Yarrell, Professors Grant and Owen, but six can be made out in the Corvid\u00e6, as stated by Savart, and seen in the figure of the Raven.\nthe developement and union of the last six or seven rings of the trachea. It is divided within into two unequal cavities by the os\nFig. 914.\n2. 1.\n1. The inferior Larynx of the Raven,\nShewing the six muscles, a, b, c, d, e.f which modulate the voice on one side.\n2. Anterior view of the same,\nShewing the membrana tympaniformis, g.\ntransversale, of which the left is always the largest. The figure of the os transversale is very similar to that of the arytenoid cartilage in the human larynx, consisting of prominences, ridges, and base : the superior prominence of this bone projects high into the tube of the trachea, and completely divides the larynx at its base. The ridge on its left side is furnished with a salient lamina, corresponding to a thin transparent semilunar lamina, situated opposite to it : the latter is placed at the entrance of a small osseous cavity at the inferior boundary of the left larynx; a still larger osseous cavity lies obliquely above the semilunar membrane. The air sets this membrane in motion as it circulates in the left chambers of the larynx, and contributes to the production of the well-known peculiar character of voice in this bird. On the right side the cavity of the larynx is of smaller dimensions, of less irregular form, and destitute of those prominent ridges and salient lamin\u00e6 within. There appears to be a small tympanic membrane attached to the first few rings of the bronchus on the right side.\nIn the Mergus serrator the inferior larynx is partly osseous, and partly membranous : it consists of two irregular cavities. The os transv\u00e9rsale, i (fig. 915), which has an extensive union along its posterior edge and base with the bony boundaries of the larynx, divides this tube into two parts, except at its superior prominence, where it leaves a channel b for the air from the right bronchus^ to penetrate the trachea. On the right lateral surface of the larynx, a large oval membrane","page":1497},{"file":"p1498.txt","language":"en","ocr_en":"1498\nVOICE.\nforms the boundary : the rest of this cavity is composed of bone. On the left side the larynx is furnished with four membranes, of unequal dimensions, which are inclined to each other at different angles ; of these membranes three are lateral, and the fourth forms the base. The internal lateral membrane b lies almost parallel to the superior promontory of the os transversale i, from which it is separated by a channel, leading from the left to the right larynx .* Through this channel the air from the left bronchus must pass to reach the trachea. The internal lateral membrane has a free salient edge inferiorly, over which the air brushes in its passage from the lungs to the trachea.f The posterior, anterior, and lateral mem-\nFig.\nbranes are supported by bony rings, of which the anterior is the largest. The membrane forming the base is penetrated by the left bronchial tube, and is connected with several of the bronchial rings through the medium of the membrana tympaniformis. Thus the air from the lungs throws into vibration one large membrane in the right, and four in the left larynx, all of unequal dimensions, and constituting a very complex piece of mechanism.\nIn the M. Merganser or Goosander the inferior larynx is most developed on the left side h (fig- 916), which is chiefly membranous, while the other side d is composed principally of bone. On the left side there are four irregular membranes, \u00ab,5, c,supported\n915.\nTwo views of the Inferior Larynx of the Mergus Serrator.\nby bones, and that on the external ring h. The os transversale is very small and does not reach the free edge of the internal membrane b, which is similar to that of the JMergus serrator, thus leaving a communication open between the right and left side of the cavity of the larynx, through which the air from the left lung must pass to reach the tube of the trachea, which terminates on the superior part of the right side of the larynx. The right side is chiefly surrounded by bone externally, having a very small oval membrane anteriorly, and is furnished with a small tympanic membrane at its junction with the bronchus. The salient portions of these membranes, and the small membrana tympaniformis are best adapted for putting the air into a state of vibration, reinforced by\n* The area of this channel is increased by an osseous cavity which is formed by the posterior concave surface of the ridge g, lying externally in front of the larynx.\nf Beneath the inferior point of attachment of the internal lateral membrane, the above-mentioned conical osseous cavity passes vertically downwards c terminating between the bronchi in a kind of cul de sac.\nthe chambers of which the larynx is com posed.\nFig. 916\nInferior Larynx of the M. Merganser.","page":1498},{"file":"p1499.txt","language":"en","ocr_en":"1499\nVOICE\nIn the female the larynx is of a much simpler structure, the external wall is composed of several consolidated rings, those situated below the os transversale terminating in the membrana tympaniformis between the last bone of the larynx and first of the bronchus.\nIn the Anas clangula we find another variety in the structure of the vocal organs. The inferior larynx is nearly of a semilunar form, with its convex surface directed exteriorly ; it is situated obliquely to the axis of the trachea. It is partly bony, and partly membranous, and divided into several cavities. A large semilunar bone forms the principal framework of the whole larynx. On the left side there are two cavities, one of which is situated above the other. The superior cavity is formed by a groove in the semilunar bone by which it is bounded both externally and internally, but is furnished with a membrane above. At the posterior extremity of the bone forming the floor of this cavity, there is a perforation by which the air in the inferior cavity from the left bronchus is admitted. The inferior cavity lies at the base of the larynx, and is connected with both bronchial and tracheal apertures; it is bounded anteriorly by the semilunar bone, and inferiorly by the basilar membrane.\nOn the right side the semilunar bone forms externally a protuberance, which is concave within, forming the anterior and lateral boundary of a large cavity which lies between the bronchial and tracheal apertures. This cavity is subdivided by bone and membranes into two irregularly formed cul de sacs, which are nearly parallel to the axis of the trachea.\nThe os transversale is a very irregularly formed bone, as in the Mergansers, dividing the larynx into two unequal and unsymmetrical parts ; its superior prominence, which is conical, penetrates the trachea nearly one-eighth of the entire length of that tube. The rings of the trachea here are no longer entire but divided anteriorly and posteriorly by a dense membrane, and in some places by osseous interposed substances, the whole being supported within by the os transversale. A basilar membrane supported by the semilunar bone, forms the floor of the larynx. This membrane is perforated by the bronchial tubes, and is connected with the bronchi by means of the membrana tympani. In the female, the left side of the larynx lies above the right, as does that of the male, and the base is likewise oblique to the axis of the trachea. The trachea of the male has an enlargement occupying about one-fourth of its length, its size being regulated by an additional pair of muscles, which draws the rings of that part either into an oblique, or into a nearly horizontal position.\nThe whole of this complicated mechanism is concerned in producing the tones peculiar to the A. clangula.\nThe A. rufina, or red-breasted whistling duck, presents another instance of laryngeal structure peculiar to itself ; but our limits will not admit our giving its anatomy in detail : let it\nsuffice therefore to mention, that its left cavity, which is largest, is chiefly membranous, whilst the right is almost entirely osseous, and somewhat resembles in external form the larynx of Mergus Merganser. A. muscatus, A. Pe?ielope, or widgeon, and A. \u00c6gyptiaca, have also bony enlargements of the inferior larynx ; but the Anser domesticus, and the Larus, and Ardea, with some others amongst the Grallatores, are destitute of these enlarged cavities common in the order Anas. The organs of voice in the Palmipedes are, with a few exceptions, only provided with one pair of muscles.*\nIn the Gallinace\u00e6 the structure of the inferior larynx is more uniform, simple, and symmetrical than in the Palmipedes. In the male Phasianus gallus, the common cock, this larynx is composed externally of two or three of the lower half rings of the trachea, connected in the inside with the os transversale both anteriorly and posteriorly, through the interposition of two triangular laminas given off by it, which are also connected with the bronchi. Between the rings of the larynx there is interposed a membrane which forms the side of the glottis externally. The inferior portion of the trachea is much compressed laterally. The inferior larynx of the pheasant does not differ materially in structure from that of the cock. In the partridge the os transversale is attached immediately to the last half ring of the larynx. In the Gallinace\u00e6, owing to the os transversale lying below the last semilunar rings of the larynx, the membranes on each side are immediately opposite to each other, so as to form the two sides of the glottis, and the larynx is not entirely a double reed as in the Sylviad\u00e6, in which the membrana semilunaris forms with the membrana tympani the interior lips of the glottis, and divides the larynx into a double organ of voice. In this respect the structure of the larynx in the Gallinace\u00e6 is intermediate between the parrots and the singing birds. The trachea being compressed laterally, and the glottis very straight, these, according to Cuvier, may be considered the causes of the acute sounds which these birds produce. They are provided with one pair of muscles. In the Indian pigeon, however, the sternotracheal muscles divide, and send a few fibres to the inferior larynx.\nIn the Falcons, the larynx being provided with but one pair of muscles, viz. the sternotracheal. its structure is much more simple than in the singing birds. The membrana tympani is however large, but does not appear to give off any semilunar membrane. The bronchial rings are distant from each other, and bound together by thin membranes ; the rings of the larynx are almost in juxtaposition, leaving no vibratile membranous space between them ; consequently the membrana tympani is the chief vibrating tissue. The order also has one pair of vocal muscles.\nScansores.\u2014 In the parrots the inferior\n* The exceptions in this order are the Velvet duck, the Golden Eye, the Red Breasted Merganser, and Ganet, in which there are two pairs.","page":1499},{"file":"p1500.txt","language":"en","ocr_en":"1500\nVOICE.\nlarynx differs in structure from that of any other order of birds. They have no os transversale dividing the vocal organs, which is consequently a single larynx. The segments of the rings in which the lower end of the trachea terminates are consolidated together on each side. The last two of these segments are of a crescent-like or semilunar form, with its axis nearly perpendicular to the axes of the ring of the trachea ; they are concave to each other, and their extremities articulated together, forming an elliptical space which is furnished with a thin vibratile membrane, as seen in fig. 917. At their junction is the joint or axis on which they revolve upon each other, and by which the tension of the membrane of the glottis is capable of being varied.\nFig. 917.\nInferior Larynx of the Parrot, a, b, tensors of the glottis ; c, laxator of glottis.\nThe glottis is formed on each side by the elastic membranes that fill the space between the semilunar bones; these membranes leave a narrow chink between them through which the air from the lungs passes, and puts them in a state of vibration whenever the bird draws them sufficiently tense; for this purpose they are provided with three pairs of muscles, of which two a, b, are tensors, and one c laxator of the glottis.\nThe trachea of birds comprehends that portion of the vocal tube which lies between the superior and inferior larynx ; its diameter and length generally depend on the length of the neck of the bird. In the common crane, the trachea after making its exit from the thorax, penetrates the sterno-tracheal space, and then making four turns upon itself in the same plane, it leaves the breast bone to follow its course into the neck : by this arrangement the vocal tube is greatly lengthened for the purposes of voice, and the surface of the sternum increased for the attachment of the great pectoral muscles without adding materially to the weight of the bird. The voice of the crane is very sonorous, and may be heard at a great distance.\nIn Bewick\u2019s swan (fig. 918), the manner in which a considerable additional length is given to the trachea by its convolutions, will be evident upon an inspection of the figure.\nThe spoonbill presents another remarkable instance of convoluted trachea, doubling twice upon itself. Other examples of con-\nvoluted trachea are found in the Gul-linaceae ; as in the Rhynch\u0153a Australis, and Phasianus Purraqua. In the singing birds the trachea is a cylindrical tube ; the rings which are at first cartilaginous become ossified with age. The tracheal rings, which are entire in the adult state, being connected by elastic membranes, are at a sufficient distance from each other to allow of all the movements of the neck.\nFig. 918.\nInferior Larynx and convoluted Trachea in Bewick's Swan, from Yarrell.\nThe diameter of the trachea in singing birds is nearly uniform and proportional to its length ; but among the Palmipedes, the Mergansers, and some species of Anas, as the A.fusca and A. rufina, there are tracheal enlargements with additional muscles, to control their dimensions. The number of rings in the trachea of some birds is very great, surpassing that of any other class of animals. In the Ph\u0153nicoptenis, according to Dr. Grant, there are at least 350 rings.\nPhysiology of the Voice of Birds. \u2014 The vocal apparatus of birds consists of the lungs, larynx, and trachea, representing a wind chest, reed, and pipe. The inferior larynx has been proved by Cuvier to be the organ in which the sounds are generated. To ascertain this fact, he divided the trachea of a blackbird about the middle of its length, thus preventing the passage of the air through the superior orifice ; the bird notwithstanding continued to sing, though the tones were more feeble than before. In a second experiment on the pie, performed in the same manner, the bird cried with as great intensity of tone, and with the same acuteness as before the operation, for the space of about ten minutes when the blood from the wound being drawn into the larynx suffocated the animal. These experiments, however, were sufficient to prove that the sound did not arise from the superior larynx ; and when we view the structure of that organ, and, find it destitute o\u00a3 vocal ligaments, or any salient membranous laminae, and bounded by cartilaginous or osseous matter, and compare it with the complex organization of the inferior larynx, we might","page":1500},{"file":"p1501.txt","language":"en","ocr_en":"VOICE.\t150\u00cf\nwithout experiments conclude the latter to be the organ of sound.\nThe superior larynx nevertheless performs an important office,both preventing the passage of the food into the wind-pipe, and modifying the sound of the voice. It can be opened and closed with rapidity, in singing birds ; and is actively employed in the production of melody : we can easily witness its simultaneous movements with the mouth, in the song of the canary, linnets, and others. Its influence on the pitch is according to Savart, but little, not amounting to more than a semitone. The inferior larynx may be considered a reed prefixed to a tube. The salient laminae of the membrana tympaniformis, and the mem-brana semilunaris are especially adapted to produce a series of vibrations, when a current of air is forced into the bronchi. It is indeed only necessary to dissect out the vocal tube of a bird, (such as that of the goose for example), and blow into it by the mouth, to elicit sounds. In the singing birds, which have the lower larynx furnished with the most elaborate muscular apparatus, the tension of the vibra-tile membrane of the glottis can be regulated with precision, so as to enable them to effect the varied melodies which nature or art dictates. In order to prove the duplex structure of the inferior larynx, Savart divided the recurrent nerve on one side in the living bird, after which it continued to sing with all the modifications of its melody as before. We agree as to the duplex office of the lower larynx in singing birds ; but in them the semilunar membrane appears common to both sides, as is also the os transversale. Savart considered the semilunar membrane to be chiefly developed in those birds which have the most reedy quality of voice, the speaking birds for instance, such as the jays, pies, &c., but that, in the production of the flute tones in singing birds, it is more relaxed, and the glottis more open. He observes that, in making a transverse section of the trachea in the living bird, which also cuts the recurrent nerve, and produces a relaxed state of the glottis, the sounds become less \u2018 criard,' and less \u2018sourd\u2019 ; but, as birds thus maltreated suffer greatly, he recommends the section of the recurrent nerve only. It is one of the most difficult subjects in acoustics to determine theoretically the sound which many of the maleNatatores ought to produce, such, for example, as the Anas domesticus, A. clangula, Mergus serrator, and M. merganser, the structure of whose larynges has been briefly described; and, when we consider that these larynges are composed of chambers of varied dimensions, bounded by walls partly membranous and partly osseous, the membranes being of unequal area, and perhaps unequal tension, we may have some notion of the extreme difficulty of the inquiry, when some of the greatest mathematicians of the past and present age have as yet been unable to determine analytically the law of the vibration of a single piece of stretched parchment, like the drum.\nExperiment shows that asingle membranous\nstretched disc will produce many other, besides its fundamental and harmonic sounds ; we need not, therefore, be surprised at the discordant tones which many of theNatatores are well known to produce. The reason why short tubes, such as the tracheas of many small birds, produce tones of a very grave pitch, has already been satisfactorily explained by Savart. We observe, however, that, in those birds in which the trachea is shortest, the diameter smallest, and the walls very elastic, the voice is most acute. The muscles which vary the tension of the walls of the vocal pipe are in continual action during the modulation of the voice, in order to adjust the tube of the trachea to the pitch of the glottis; but the number of vibrations is doubtless determined by the glottis, and reinforced by the walls of the pipe, as in Mammalia. The cavities in the trachea of some of the Natatores must certainly influence the timbre, or quality of the voice of those birds. In the common crane, and other birds whic h have a convoluted trachea, the tones ought to be grave in proportion to its length, if the number of vibrations is determined by the length, as in musical instruments.\nThe voice of birds, as of other animals, is always in a minor key ; but to describe the melody of each bird would be foreign to our subject. The range of notes is generally within an octave, though they can greatly exceed it. In the parrots, which have a voice of great power, the inferior larynx is single. The two membranes of the larynx leave a narrow chink between them, through which the air is forced from the lungs. These membranes, vibrating in all their dimensions, produce that harsh and disagreeable quality of sound peculiar to them. They can also whistle, during which the glottis is probably silent, and the column of air vibrates as in a flute, when a vibratory movement being communicated by the air, traverses the elastic walls of the tube. Besides the power of speech possessed by some birds, many can imitate almost every sound thev hear. The blackbird has been known to imitate the song of the nightingale, the crowing of the common cock, and the cackle of the hen ; the jay is said to mock the notes of the greenfinch and the neighing of the horse so closely, that it was scarcely believed to be a bird by those who heard it;\u2018also the calling of fowls to their food, and the barking of the house dog.\nThe sounds uttered by birds are so various that to describe them physiologically in detail would occupy a volume ; let it therefore suffice, in concluding this section of our article, to mention that the voice of birds has been made the theme not only of the naturalist, but also of numerous eminent writers both in prose and verse.\nVoice of Reptiles. \u2014 The mechanism of the vocal organs in reptiles presents very diversified forms. The larynx varies considerably in structure, not only in different orders, but in different genera of the same family. It would therefore be impossible to compress within the limits assigned to this article the","page":1501},{"file":"p1502.txt","language":"en","ocr_en":"1502\nVOICE.\nminute anatomy of the several species ; they have been recently investigated and detailed in a monograph by Henl\u00e9.\nSauna.\u2014 In the Crocodile the larynx is composed of three cartilages, namely, the thyroid and cricoid consolidated into one ring-formed cartilage, called the thyro-cricoid, and the two arytenoid cartilages. The basi-hyoid element of the hyoid bone is expanded into a disc ; and lies in front of the larynx, which it protects and supports. The arytenoid cartilages are connected with the superior margin of the thyro-cricoid by a membranous suture, but nothing approaching to a joint furnished with ligaments and synovial membrane is observable. The mucous membrane of the larynx is reflected over the inferior margins of the arytenoid cartilages, and forms a deep pouch beneath them, leaving a free fold with a margin on each side; so that, when these cartilages are brought near each other, this fold forms the vocal cord, and produces the tones peculiar to the Alligators In the Cam\u00e9l\u00e9on the larynx is provided with a sac in front, similar to that observed in some of the Quadrumana. The air passes to and from this sac by means of an opening, lying between the lower margin of the larynx and the first ring of the trachea. The larynx of this animal has been very minutely described by Treviranus.\nSome reptiles have a membrane at the base of the tongue, which answers to the epiglottis ; others have a cartilaginous epiglottis ; others again a mere bony or cartilaginous processus epiglottieus, as in birds. \u201cBut,\u201d observes Henl\u00e9, \u201cthe presence of this process does not imply that there is no epiglottis, or conversely, the presence of an epiglottis that there is no processus epiglottieus.\u201d Cuvier described five cartilages in the larynx of the crocodile, but it is now generally admitted that he was mistaken.\nThe vocal cords are more perfectly developed in the Gecko, and the cam\u00e9l\u00e9on, than in the crocodile. They are broad membranous folds passing from the bases of the arytenoid cartilages to the inner surface of the crico-thyroid.\nIn the Lacerta a very thin membranous fold is found passing from the bases of these cartilages in the position of the vocal ligaments ; but Henl\u00e9 is of opinion that the acute chirping tone of the lizard depends rather on the vibration of the margins of the glottis, than on these folds, which are incapable of being approximated to each other, or brought into a state of tension.\nChelonia.\u2014'The vocal organs of the Chelonia are not adapted for perfect intonation of the breath, being destitute of vocal cords. The superior portion of the larynx is surrounded by, and connected with the basi-hyoid element of the os hyoides as in the Sauria. In the Emys, and the Testudo, the thyroid cartilage is annular, and distinct from the cricoid ; the arytenoids are triangular, and the internal surface is much enlarged, owing to the very concave form of the larynx. In the Midas, the aditus laryngis is furnished with a fold of\nmucous membrane, which serves for the production of certain sounds. In the great tortoise of Madagascar, Cuvier describes a triangular membranous crest attached to the base of the larynx which, ascending to its opening, divides it into two parts, and is analogous to what is found in the superior larynx of some birds. Meckel found the same kind of crest in T. tabulata, but it is absent in T. Gr\u0153ca and several other species. The muscles of the larynx are the constrictor, and the dilator aditus laryngis.\nOphidia. \u2014 In this class the larynx is very little developed, with regard either to volume or to mechanism. The upper rings of the trachea are consolidated into a crico-thyroid cartilage, to which the arytenoids are attached. In some species these are sessile, mere processes of the crico-thyroid ; and in others, they are divided from it by a suture, but in the pythons and boas they are free. The processus epiglottieus is nearly quadrangular in the Boa: the vocal cords are absent, and therefore the voice is reduced to a mere hissing sound, which is produced by the breath passing over the edges of the aditus laryngis. The muscles of the larynx are the elevator, depressor, dilator, and compressor laryngis.\nBatrachia. \u2014 In the Batrachia the two arytenoid cartilages form a considerable portion of the frame of the larynx, and the cricoid, with a few exceptions, is a complete ring. The arytenoids are triangular, and their apices being upwards form the superior lateral boundaries of the larynx. The vocal cords pass from end to end of the bases of the triangles. According to Henl\u00e9, the whole of the tailless Batrachia, except the Pipa and the Dac-tylethro, have vocal cords. In Bufo there are two pairs of vocal cords (fig. 919), corresponding to the inferior vocal cords in Mammalia.\nFig. 919.\nBufo.\na, and b, semilunar folds of the superior vocal cord ; c. inferior vocal cord ; d, lung.\nAbove and below the vocal cords there are sacs lined with mucous membrane, and bounded by the arytenoid cartilages. Between the vocal cords a small cartilage is sometimes found.","page":1502},{"file":"p1503.txt","language":"en","ocr_en":"VOICE.\n1503\nIn Bombinator ignens, Hyla verrucosa, and others, the arytenoid cartilages are regular obtuse-angled, and nearly equilateral triangles. In B. cinereus they are more acute-angled, and directed backwards. The vocal cords in bufo are very thin elastic membranes, such as might be expected to produce the croaking deep tones of these batrachia.\nIn Pipa the larynx is a very peculiar piece of mechanism ; the arytenoid cartilages being convex externally and concave internally, so that when the entrance to the larynx is closed they form a dome over the windpipe, which Cuvier has compared to a kettle-drum.\nIn Rana temporaria, R. esculenta, and Hyla, the males are provided with two sacs, which open by a straight canal into the larynx. These sacs are situated on each side of the lower jaw, and are capable of considerable distension, when filled with air during the cry of the animal. Cuvier, Roesel, and Blumenbach, describe only one sac in Hyla ; but Meckel, as well as Henl\u00e9 and myself, found two sacs, as in the other frogs. These sacs doubtless exert a powerful influence on the quality of the sounds which frogs utter, analogous to the influence of similar sacs which exist in many of the higher animals.\nFig. 920.\nRana temporaria.\na, tongue ; b, os hyo\u00efdes ; c, superior vocal cords ; d, inferior vocal cords; e, pharynx; f, right bronchus.\nThe muscles acting on the larynx in Batrachia are the dilator aditus laryngis and the constrictor aditus. Besides these, there is found in the tailless Batrachia a third muscle, the compressor glottidis, which in Brito arises from the columella*, and is inserted into the posterior point of the arytenoid cartilage. Its use is to compress the larynx, to bend the posterior angle of the arytenoid outwards, and to expand the vocal ligament. It is the most important muscle connected with the voice in the tailless Batrachia. Its course varies in different species, and is absent altogether in Pipa.\n* One of the inferior processes of the os hyoides.\nIn Proteus anguinus the most simple form of cartilaginous larynx is found, consisting of lateral cartilaginous strips, divided in two on each side ; the superior portion answering to the arytenoid cartilage of the higher orders of animals, the inferior to the laryngo-trachealis cartilages.\nIn the Triton, and Salamander, the larynx consists of a membranous sac, which is kept open by the lateral cartilages of the vocal tube. Hence we learn that the arytenoid cartilages do not wholly disappear, until the larynx becomes entirely membranous.\nInsect a. \u2014 A large number of insects are mute ; some produce their sounds merely by friction, and others by the passage of the air through the thoracic spiracles. The sounds produced by friction are denominated stridulation ; those by the air from the tracheae, buzzing, or humming (bourdonnement), &c. Organs adapted to produce stridulation are found in the Orthoptera, Omoptera, and some of the Coleoptera.\nGrylli.\u2014In the Gryllus campestris (fig. 921) the elytrum is composed of dry, thin, translucent membranes, forming two planes, united and strengthened at their junction by four longitudinal and parallel nervures ; one of these planes lies on the back, and the other on the side of the insect. The former of these planes is divided by a series of regularly curved nervures, into a number of areoles. The musical apparatus may be divided into two systems, the first composed of four oblique nervures, which terminate in a strong nervure, serrated like a file (a) ; this may be considered as the bow. The second is formed of three nervures, which take their origin in a remarkable point in the internal border of the elytrum, furnished with a tuft of short stiff'hairs, or brush (5); above this point is found a firm, transparent, and nearly triangular disc or sounding plate *, surrounded by a nervure. When the insect cries, the wings are crossed, and the bow rubbed rapidly across the whole length of the Fig. 921.\n1. 2.\nElytra of Gryllus campestris. disc or sounding plate, whereby the whole of both elytra are put in a state of vibration, and the stridulous sounds peculiar to these grylli result. The pitch of the sound of the house cricket is very acute, being equivalent to about 4096 vibrations in a second.\nCicad\u0153, Cigales. \u2014 The Cicad\u00e6 have their musical instruments inclosed in the interior of the abdomen. Reaumur gives a detailed description, illustrated by drawings, by which they may readily be recognised. These instruments, he says, are contained in the abdo-\n* Termed by M. Goureau the \u00ab chanterelle.\u201d","page":1503},{"file":"p1504.txt","language":"en","ocr_en":"l\u00f4\u00fc-i\nVOICE.\nminai cavity, divided into two cells by a scaly partition of a triangular form, covered by two cartilaginous plates, acting as shutters or opercula. When viewed from the abdominal surface, each cell presents exteriorly a white folded membrane with radiated reflections, which he terms the mirror. On opening from the upper surface the part of the abdomen corresponding to the cavity, we perceive on each side a plaited membrane, dry and sonorous, which is moved by a powerful muscle, composed of straight parallel fibres springing from the scaly partition ; this membrane is the tymbal. In order to bring into play an instrument so complicated, Reaumur states that the insect alternately contracts and relaxes the muscle attached to the tymbal, and by this means produces the sound. He believes that ** this sound is augmented in the drum, and that this portion of the vocal organ has no other use than to give it brilliancy.\u201d He also imagines \u201c that the trochanter of the haunch performs the office of a curb, and prevents the operculum from being too much elevated during the song. Some doubts have arisen with regard to this simple explanation of the song of the Cicad\u00e6, and entomologists have concluded that the air performs an important part in the formation of the voice, and that it is due, at least in a great measure, to a rapid current issuing from the stigmata of the metathorax, which resounds within the organs above described.\u201d\nThe humming, or buzzing of Insects.\u2014 It has been supposed by some entomologists that the hum of insects is produced by the oscillations of their wings during flight, and this supposition is strengthened by the fact that the tones are altered during the suspension of the insects in the air, and that the sound becomes more acute when the tips of the wings are removed. This hypothesis will not, however, bear the test of rigid investigation.\nIt was observed by John Hunter, \u201c that insects emitted sounds after their wings were cut off.* De Geerf, finding that after he had cut off the wings, winglets, and poisers, the buzzing continued, placed the insect under a microscope, and observing that the stumps of the wings were in rapid motion, he pulled them off by the roots, on which the buzzing ceased -, and hence he inferred that the sound was produced by the vibrations of the wings. But it is not surprising that insects, after such mutilation cease to emit any sound. Bur-meister j: is of opinion that the sounds of some Diptera, such as Tabanus bovinus, are produced by a stream of air rapidly transmitted through the thoracic air-holes during flight. He has described and figured the mechanism of the thorax and the air-holes of the Eristalis ienax, which is as follows : \u2014The aperture of the hinder air-hole is provided with a sphincter muscle, perpendicular to the inner surface of which are sixteen or eighteen horny lamellae, of the same breadth as the muscle, and connected in\n* Phil. Trans. 1792.\tf Vol. ii. p. 13.\nX Art xvi. p 377. Taylor\u2019s Scientific Memoirs.\nthe middle by another longitudinal horny band. The sphincter muscle is lined with a membrane clothed with feathery hairs, which cover the air-hole like a sieve, and exclude foreign bodies. He leaves it to naturalists to decide whether or not this mechanism contributes to the formation of the sound ; adding that either way it is of little consequence, as many insects have no such lamellae. He observes that when the insect sits or crawls it breathes through the air-holes of the abdomen,but during flight through those of the thorax. He considers the hum of insects to be in reality a whistle. The pitch of this hum is hitherto unexplained, although it is quite certain that it does not depend upon the number of the vibrations of the wings, for in a favourable light the motion of the wings of many insects, whose hum is of a high pitch, can be clearly detected ; but, if that pitch were owing to the vibrations of the wings, their number would necessarily be so great as to render the motion imperceptible.* The author has recently examined, with Professor Queekett, the spiracles of other insects, such as the blue-bottle fly, and the humble bee, and has discovered in them a beautifully organised valvular opening, capable of producing the sounds which these insects emit during flight, f In fig. 922. is shown one of the large thoracic spiracles of a blow fly (Musca vomitoria) ; it consists of two valves, one much larger than the other, each\nFig. 922.\nThoracic spiracle of the blow-fly, Musca vomitoria.\nbeing provided with numerous branching horny filaments or hairs which serve as a support to the thin membrane forming the valve ; a somewhat similar form of spiracle occurs in the humble bee, (fig. 923). The valves are nearly of equal size, and the branching hairs are much stronger and more numerous than those in the blow fly.\n* Those who wish to pursue the subject further may consult the second note to p. 425. art. Motion., f The pitch of the blue-bottle fly ranges, in different species, from 288 to 341 vibrations in a second.","page":1504},{"file":"p1505.txt","language":"en","ocr_en":"WRIST-JOINT (Normal Anatomy).\nBesides stridulation, and humming, some insects, such as bees, emit a cry, or, as the French entomologists term it, piaulement. M. Goureau supposes this variety of voice to be used, when bees swarm preparatory to their emigration. He remarks that those insects which produce the sound by friction are not singers, but musicians ; and that insects in general make use of their voices to communicate certain ideas and sensations.\nFig. 923.\nThoracic spiracle of the Humble Bee (Bombus terrestris').\nIn insects we find a great diversity of beautifully contrived mechanism for the modulation of sound, all answering the same end in the economy of these countless myriads of minute beings.\nBibliography .\u2014 J. Casserii Placent. De Yocis Organis, Ferrar, 1600, fol. Hieron Fabric\u00fc, Oper, omn. Lips. 1637. fol. Aristotle, tom. ii. p- 281. Galen, tom. iv. chap. xi. Dodart, M\u00e9m. de l\u2019Aead. de Paris, 1700, 1706, 1707. Wallis (/.), De Lo-quela, 1740. Ferrein, ibid, 1741. Bertin, Nouveaux Sys. de laYoix, 1745. Herrissant, Mem. del\u2019Acad, de Paris, 1753. Steller, Beschreibung von Sonderbaren Meerthieren, Halle, 1753. Busch, De Mecha-nismoOrgani Yocis,Groning. 1770. Pallas, Spicilegia Zoolog. Berolini, 1777, 1778. Vicq-D'Azyr, M\u00e9m. de l\u2019Acad., 1779. Camper, Phil. Trans., 1779. Vogel (R. A.), De Laryng\u00e9 Humana; et Haller, Element. Physiol, tom. iii. Arol. ii., 1787. Amman (J. C.), 1790. Humboldt and Bonpland, Eecueil d\u2019Observ. de Zool., Paris, 1805, fol. Blumenbach, Handbuch der Vergleichenden Anat. G\u00f6ttingen, 1805. Dutrochet, Essai d\u2019une Nouvelle Theorie de la Yoix Humaine. Paris, 1806. Young {Dr. T.') Lectures on Natural Philosophy, vol. iv., 1807. Yarrell, Linn. Trans, vol. xvi. ' Gockel, De Yoce Animal. Mix. Acad. Nat. Cur. Wolff, Diss. Anat. de Organo Vocis Mam-malium. Berol. 1812. Savart, Annal, et de Chemie de Physique, tom. 24. 26. 29. 32. Liscovius, Theorie der Stimme. Leipz. 1814. Magendie, Precis Element. de Phys. Perrault, M\u00e9m. pour servir \u00e0 l\u2019Histoire des \u00c0nim. tom. iii. Biot, Pr\u00e9cis El\u00e9ment, de Physique, Paris, 1824. Chladni, in Gilbert\u2019s Ann. 76. p. 187. Bennati, Recherches sur le M\u00e9canisme de la Yoix Humaine. Paris, 1832. Willis, Trans. Phil. Soc. Cambridge, 1832. Sir C. Bell, Phil. Trans. 1836. Gurlt, Vergl. Anat. der Hauss\u00e4ugethiere, 1836. Goureau, Essai sur la Stridulation des Insectes. Ann. de la Soci\u00e9t\u00e9 Entomologique. Paris, 1837. Burmeister (H), On the Cause of the Sound produced by\nVOL. IV.\n1505\nInsects in Flying, Taylor's Scientific Memoirs, vol. i. 1837. Meckel, Anat. Compar\u00e9e, tome dixi\u00e8me. Paris, 1838. Henl\u00e9, Des Kehlkopfs der Reptilien. Leipzig, 1839. Carus, Lehrbuch der Vercliliehenden Zootomie, Bd. 1. Wagner, Lehrbuch der Ver-chleichenden Anat. Treviranus, Erscheinungen und Gesetze Organischen. Bd. 2. Cuvier, Anat. Compar\u00e9e, tom. viii. Paris, 1846. Mayo, Outlines of Physiol. Lehfeldt, Diss. de Yocis Formatione, Berol. M\u00fcller, Elements of Physiol, by Baly, p. 1002.\n( John Bishop.)\nWORMIANA OSSA (vide Cranium).\nWRIST-JOINT (Radio-carpal Articulation), Normal Anatomy of the. \u2014 The articulation of the wrist results from the union of the bones of the fore-arm with those of the hand, and is constituted by the contact of the lower surfaces of the radius and of the triangular interarticular cartilage with the scaphoid, lunar, and cuneiform bones of the carpus. The radius and the triangular fibro-cartilage accordingly present a uniformly smooth and slightly concave surface, whilst the first three bones of the carpus afford a surface which is as uniformly convex. The transverse measurement of these articular surfaces is greater than the antero-posterior, since the former averages one inch and a half in the adult male, whilst the latter scarcely exceeds three quarters of an inch.\nIn this joint are found all the anatomical dispositions which characterize other arthrodial articulations : the bones are invested with cartilage, lined by a synovial membrane, and present smooth surfaces which deviate but slightly from being planiform ; and lastly, the ligaments connecting the osseous surfaces are so disposed, as to admit of all the free gliding motions which are indispensable to the hand as an organ of touch and of prehension.\nIt is proposed in this article to describe, seriatim, the different structures which enter into the composition of the radio-carpal articulation, with their relative anatomy, but for a detailed account of the surgical anatomy of the region of the wrist, the reader is referred to the article Hand, where this subject has been fully entered into.\nI. The Bones which constitute the wrist-joint,\na. The Radius. \u2014 The lower end of the radius, which is of a quadrilateral form, is curved so as to present a concavity anteriorly, and a convexity in the opposite direction. On its different aspects various objects of interest present themselves to view, which may be thus enumerated: \u2014 Anteriorly is seen a smooth surface, to which the tendons of the flexor muscles, surrounded by their synovial sheath, are applied ; posteriorly, a series of depressions and irregular elevations are observable, the former of which indicate the course of different tendons passing to the hand. Of these depressions the most external is a broad but shallow groove, which lodges the tendons of the radial extensors of the carpus : to its inner side, but separated from it by a well-marked ridge, is a narrow deep groove, which runs obliquely downwards and outwards, and transmits in this\n5 D","page":1505},{"file":"p1506.txt","language":"en","ocr_en":"1506\nWRIST-JOINT (Normal Anatomy).\ndirection the tendon of the extensor secundi internodii pollicis. The remainder of the dorsal aspect of the radius is subjacent to the tendons of the m. extensor digitorum communis and the extensor indicis. The outer surface of the lower extremity of the radius is the least extensive, and is furnished with a shallow groove, which affords insertion to the tendon of the supinator longus, and gives passage to the tendons of two of the extensor muscles of the thumb, viz., the extensor ossis metacarpi pollicis and extensor primi internodii pollicis. \u00abThis surface is terminated inferiorly by the styloid process, which lies on a plane a little posterior to the last-mentioned groove : lastly, the inner surface of this portion of the bone presents a smooth concave surface of oval form, its long axis directed from before backwards, which serves for articulation with the head of the ulna, and enters into the formation of the inferior radio-ulnar articulation. By its inferior surface, the radius is adapted for articulation with the carpus. The aspect of the surface, owing to the curvature of the radius already indicated, is downwards and forwards, whilst at the same time it is directed slightly inwards, from its external boundary passing lower than the internal.\nThe inferior surface of the radius presents a triangular outline, the apex of which is placed externally at the styloid process, whilst the base, in the opposite direction, is constituted by the sharp margin separating the inferior from the internal articular surface on the radius, and serving for the attachment of the broad extremity of the radio-ulnar inter-articular cartilage (triangular fibro cartilage). The two margins which border this nferior articulating surface of the radius serve for the attachment of ligaments, and of these the anterior is the most prominent. Lastly, the carpal surface of the radius is divided into two portions by a ridge, which traverses it from before backwards : the external of these articular \u201cfacettes\u201d is triangular in shape, and adapted to the scaphoid bone, whilst the more internal of the two is quadrilateral, and articulates with the semilunar carpal bone.\nIt has been mentioned that the radius at its lower extremity undergoes a change of form, and that from being cylindrical higher up, it becomes here quadrilateral. This expansion of its surface takes place at the expense of its solidity, for a section of the bone shows that inferiorly the compact tissue is extremely thin, whilst the cancellated tissue is in proportion more abundant.\nThis circumstance is adduced, as in some measure explaining the frequency of fracture in this situation, an accident notoriously common.\nThe ulna is excluded from the articulation of the wrist by the triangular fibro-cartilage, which stretches across transversely between the head of the ulna above and the carpus inferiorly, and presents a surface concave in each direction.\nThe inferior surface of this fibro-cartilage is on the same plane with the inferior surface\nof the radius, and constitutes with it the superior articulating surface of the wrist-joint. The entire of this conjoint surface is somewhat oval (or diamond-shaped), and is limited externally and internally by the styloid processes of the radius and ulna respectively.\nb. The Scaphoid, Semilunar, and Cuneiform Bones of the Carpus. \u2014 The Carpus, superiorly, presents a surface which is pretty uniformly convex. That convexity, however, is slightly interrupted by the undulating lines resulting from the lateral articulations between the bones which compose it.\nThe convexity of the upper surface of the scaphoid bone is triangular in form, and articulates with the outer facette on the inferior surface of the radius; the semilunar bone is quadrilateral in conformity with the shape of the inner facette of the radius, whilst the cuneiform bone presents a surface of a triangular form, by which it comes accurately into apposition with the inferior surface of the radio-ulnar interarticular cartilage. The aspect of the radial or upper conjoint surface of those three bones is directed upwards and slightly backwards.\nII. The Ligaments.\u2014 These are placed on each of the several aspects of the wrist, and are usually designated from their position,\u2014 the anterior, the posterior, and the lateral radio-carpal ligaments. But whilst the wrist-joint is thus protected on its different aspects by ligamentous bands, it is to be observed that no distinct intervals naturally separate these ligaments from one another, so that it might with strict propriety be said that the articulation of the wrist is defended by a ligamentous envelope of a capsular form, strengthened in particular parts, but more especially laterally by other superimposed and superadded fibres.\na.\tAnterior Radio-carpal Ligament. \u2014 The fibres of this ligament are connected superiorly to the anterior margin of the lower end of the radius and of its styloid process, and to the \u201c triangular ligament,\u201d from whence they radiate to their insertion into the anterior surfaces of the scaphoid, semilunar, and cuneiform bones. Below, they are partly continuous with the fibrous fasciculi (interosseous ligament), which connect the two rows of carpal bones.\nThe fibres of the anterior radio-carpal ligament pursue a direction for the most part downwards and inwards.\nBy its anterior surface this ligament is in relation with the tendons of the deep flexor muscles, and also (but more remotely), with those of the superficial flexor, and with the median nerve, the entire surrounded by an extensive and complicated synovial apparatus. Beneath these structures, and immediately in front of the ligament, is the anastomosis, between the anterior radial and the anterior ulnar carpal arteries, which also receive tributaries from the descending branches of the interosseal, and the ascending of the deep palmar arch of arteries.\nb.\tPosterior Radio-carpal Ligament.\u2014This","page":1506},{"file":"p1507.txt","language":"en","ocr_en":"WRIST-JOINT. (Normal Anatomy).\t1507\nligament much resembles the one last described. Arising from the posterior edge of the carpal end of the radius, its fibres pass downwards and inwards to the back of the carpus, where they expand and take an extensive attachment to the three inner bones of the first range. The tendons of the extensor muscles of the fingers are related to the superficial surface of this ligament, which has also in contact with it the posterior carpal arteries from the radial and ulnar trunks.\nThe anterior and posterior ligaments are connected, both externally and internally, with the lateral ligaments, so that no portion of the periphery of the articulation is devoid of ligamentous covering\nc.\tExternal Lateral Ligament of the Wrist-Joint.\u2014The external lateral ligament is funicular in form, and connects the styloid process of the radius with the scaphoid and trapezium, the two most external of the carpal bones. The direction of its fibres is downwards and backwards. The radial artery crosses obliquely over the external surface of this ligament, and separates it from the tendons of the extensor ossis metacarpi and the extensor primi internodii pollicis. The synovial membrane lines its inner surface. When the hand is fully adducted, this ligament is put upon the stretch.\nd.\tThe internal lateral ligament.\u2014This ligament is larger and longer than the preceding ; for, notwithstanding the greater length of its styloid process, the ulna is more widely separated from the carpus than is the radius. This ligament connects the styloid process of the ulna with the cuneiform bone, giving a fasciculus to the fusiform bone and to the anterior annular ligament. The tendon of the extensor carpi ulnaris is posterior and parallel to thus ligament. The internal lateral ligament limits abduction, so as to render it the least extensive of all the motions enjoyed by the wrist joint.\nIII. Synovial Membrane. \u2014 The synovial membrane of the wrist joint is very extensive, and contains a large quantity of synovia. Its anatomical disposition is so simple as not to require any special notice ; but it may be of practical importance to remember the proximity of this structure to the synovial sacs between the lateral articulations of the carpal bones, and also its contiguity to the articulation between the trapezium and the first metacarpal bone. The former circumstance explains the facility with which acute inflammation, occurring in the smaller carpal articulations as the result of imparonychia, may be propagated to the contiguous wrist joint, where, too frequently, the morbid action thus excited proves destructive to the articulation. The latter circumstance demands our attention, since it teaches that, in amputating at the first carpo-metacarpal articulation a careless use of the knife may inflict a wound upon the wrist joint itself, from which the most serious consequences may accrue.\nThe synovial membrane of the wrist joint is separated from that of the inferior radio-\nulnar articulation by the triangular interarti-cular cartilage. In amputating at the wrist joint, if care be taken to leave the inter-articular cartilage uninjured, the motions of pronation and of supination will be left to the forearm, and may therefore be communicated to the artificial substitute for the amputated hand. In this respect, the amputation through the joint offers an advantage which is sacrificed when amputation is performed through the continuity of the bones of the forearm.\nIV. Mechanical Functions. \u2014 The wrist-joint enjoys every variety of motion included under the head of gliding motions (Bichat) ; thus it is capable of flexion, extension, adduction, abduction, and circumduction. In the motions offlexion and of extension, the carpus rolls either forwards or backwards on the lower articular surface of the radius. Flexion is limited, not only by the posterior ligament, but also by the lateral ligaments which are attached behind the centre of motion of the articulation. Extension is limited by the anterior ligament only. In adduction and abduction the carpal bones glide from side to side on the surface opposed to them. Of these motions abduction is the more limited, because, probably, the styloid process of theradius and the trapezium come sooner into mutual contact than the corresponding parts at the inner side of the joint do. In circumduction (a motion compounded of all the preceding ones), the hand moves through a circle representing the base of a hollow cone, the apex of which is at the joint. The free gliding of the carpal bones on each other causes this movement to appear more extensive than it is in reality, whilst it gives all that ease and grace to the movements of the wrist which are in so especial a manner its characteristics.\nThe wrist joint thus constituted would not, \u00e0 priori, be supposed to enjoy that remarkable immunity from accidental luxation which must be conceded to it. In truth, this articulation owes its remarkable strength and its freedom from accidental displacements to the mass of tendons which occupy its anterior and posterior surfaces principally, not to its ligamentous connections, nor to the form of its osseous surfaces. Those tendons, like so many vital ligaments kept tense as well by the tonic as by the active contraction of their muscles, and bound down by the annular ligaments, bear oft' in a great degree, all violent shocks from the joint itself, whilst, by their antagonistic resistance to each other, they at the same time maintain the bones in accurate contact.\nBut whilst, owing to these circumstances, the impetus of shocks applied to the hand are borne off\" from the articulation of the wrist, they fall in many instances with resistless force upon the lower end of the radius, which, owing to the thinness of its compact tissue, is ill adapted for opposing an effectual resistance. It has already been shown that the ulna is but indirectly connected with the carpus ; and that a layer of highly-elastic tissue\n5 d 2","page":1507},{"file":"p1508.txt","language":"en","ocr_en":"1508\nWRIST-JOINT (Abnormal Anatomy).\nintervenes between the carpus and that bone. These circumstances taken in connection with the remarkable mobility of the lower radioulnar articulation sufficiently explain why the ulna so frequently escapes injury from forces which act on the hand, and which suffice to fracture the radius. At the same time it is to be observed, that displacements of the lower extremity of the ulna are by no means unfrequent accompaniments of fractures of the radius.\n(.Benjamin Geo. M\u2018Dowel.)\nWRIST, Abnormal Conditions of. \u2014 In the following account of the abnormal condition of the different structures which enter into the composition of the wrist, we shall consider this region as formed not only by the lower extremities of the bones of the forearm and the wrist-joint, properly so called, but also by the carpus surrounded by its fibrous and fibro-synovial tissues.\nThe abnormal condition of the different structures of this region may be arranged under those which we can refer\u20141st, to congenital malformation; 2nd, to accident; and 3rd, to disease.\nCongenital. \u2014 Congenital dislocation of the bones which constitute the radio-carpal articulation may be considered rare; nevertheless, I have seen within these few years thirteen examples of this malformation. One, in which the bones of the forearm were thrown forwards and the carpus backwards. In the remaining twelve cases, the bones of the forearm were placed on the dorsum of the carpus, which they overlapped.\nThe history of congenital luxations of the wrist-joint is modern. Cruveilhier, in his Pathological Anatomy (liv. ix., 1833), has published an example of this deformity, although he was not himself aware of the true nature of the case. The example he adduces is that of an adult female, concerning whose history, unfortunately, he could learn nothing. In this case the forearm was preternaturally short, and it formed a right-angle with the hand, which besides was inclined to the radial side of the forearm; extension was impossible ; flexion, to a certain degree, was permitted ; the inferior extremities of the radius and ulna were dislocated backwards, and formed a very considerable prominence beneath the skin posteriorly.\nThe extremity of the radius was less salient, and descended much less than that of the ulna. The superior extremity of the carpus could be felt on a plane which was superior and anterior to that of the inferior extremity of the bones of the forearm.\nDissection.\u2014 The bones of the carpus were found on dissection to be in a state of atrophy, and more or less malformed ; the radius, shortened and deformed, scarcely measured five inches; the deformity principally affected its lower extremity, which was large and deeply grooved posteriorly for the reception of the tendons of the extensor muscles; the articular surface for the carpus was placed on the an-\nterior aspect of the bone; the ulna was only six inches and a half in length, its lower ex tremity, much smaller than normal, descended half an inch below the carpal extremity of the radius.\nFig. 924.\nForearm, Cruveilhier''s case.\nThe carpus was much deformed, particularly as to the first row, which was merely, we may say, in a rudimentary state. The pisiform was the only bone of this first range that was normal. The bones of the second or metacarpal row participated in the deformity. The head of the os magnum was altogether absent, and the unciform was imperfect.\nCruveilhier published the foregoing case, erroneously supposing it an example of dislocation of the wrist-joint, the result of accident. Dupuytren and Marjolin disagreed with Cruveilhier, but equally mistook the true nature of this case ; they, doubting the possibility of an accidental luxation of the wrist-joint, considered that all the phenomena which the post-mortem examination of the limb presented in Cruveilhier\u2019s example, might be accounted for by supposing the case to have been one of fracture of the radius, and consecutive displacement of the ulna.\nIt must ever appear as a matter of surprise that Cruveilhier could have supposed that this case just adduced was an old accidental luxation left unreduced, because, according to such an hypothesis, neither the arrest of development as to the length of the forearm (which only measured six inches and a half), nor the abnormal appearances observed in the bones of the carpus, could have been satisfactorily accounted for, or explained.\nIt is equally difficult to imagine how it was that Dupuytren, who had his attention so much alive to the subject of congenital luxations, should have overlooked the true nature of Cruveilhier\u2019s case, and referred the phenomena it presented to the circumstance of the radius having been broken through its lower epiphysis; no one ever heard of shortening of the radius to this amount as the result of fracture ; besides, the bones on the carpus were in a state of atrophy, and the ulna, which Du-","page":1508},{"file":"p1509.txt","language":"en","ocr_en":"1509\nWRIST-JOINT (Abnormal Anatomy).\npuytren did not suppose had been fractured, was deformed, and only six inches and a half long.\nAt the period when this case, the subject of so much difference of opinion between two such eminent pathologists, attracted the attention of the profession in Dublin, the writer had under his care, in the House of Industry, a patient who was born with deformity of both her wrist-joints and forearms, but whose right wrist-joint presented appearances closely resembling those described as characterising the deformity of the wrist and forearm in Cruveilhier\u2019s case. As the history of this woman\u2019s case was known from her birth, it was calculated to throw light on the subject in dispute. It seemed on this and other accounts so interesting, that on the 15th of December, 1838, 1 laid it before the Pathological Society in Dublin. It was as follows : \u2014\nCase II. \u2014 Deborah O\u2019Neil, aged thirty, has been an inmate of the House of Industry,\nfor the last seventeen years. She is liable to occasional attacks of epilepsy. She cannot be said to be insane, but she is wayward and refractory, and will not submit to any rational control. Yet she is very industrious. Her upper arms and hands bear in size and length a just proportion to the rest of her stature, which is about the middle size, but her forearms appear scarcely more than half their normal length.\nHer left forearm is dislocated forward at the radio-carpal joint, while the right forearm is dislocated, as in the preceding figure, backward on the dorsum of the carpus.\nThe lower extremities of the bones of the right forearm could be seen and felt on the dorsum of the carpus, where they formed a very remarkable projection. The lowest extremity of the ulna could be seen to descend below the level of the lowest extremity of the dislocated radius, and when the hand of the patient was flexed could be made very promi-\nFig. 925.\nHight Forearm, dislocated at] Wrist. Case of O'Neil.\nnently to distend the skin posteriorly. When the surgeon introduced his fingers in front of the wrist-joint, and made a slight extension of the hand, the superior extremity of the carpus could be felt to be placed superiorly and anteriorly to the lowest extremities of the bones of the forearm. The hand inclined to the radial side, it could be extended on the forearm freely, but flexion was incomplete.\nThe left wrist-joint presented an unique example of dislocation of the bones of the\nforearm exactly in the opposite direction to those already described. The forearm was thrown forwards, and the carpus with the hand on the back of the radius and ulna(^?g. 926.).\nThis woman presented a very grotesque appearance in consequence of the remarkable shortness of both her forearms (Jigs. 926. and 927.) ; still she had a very good use of her hands, and showed admirable dexterity and skill in cutting out minute patterns on paper with her scissors.\n5 d 3","page":1509},{"file":"p1510.txt","language":"en","ocr_en":"1510\nWRIST-JOINT (Abnormal Anatomy).\nAs to this case of Deborah O\u2019Neil, no am- been for many years previously, an inmate in biguity existed. At the time the writer thus the House of Industry, under the constant laid her case before the meeting, accompanied observation of the whole medical staff of the by casts of her forearms, she was, and had institution. The history of her life was known.\nLeft Forearm.\nIt was stated that she never met with any accident, and that the peculiar deformity observable in each forearm and wrist-joint had existed from her birth.\nThe writer, in continuation, observed, that while congenital malformation was known very frequently to affect simultaneously both sides of the body, yet it would, on the other hand, be very difficult for any one to suggest what probable accidental causes could be imagined capable of dislocating the bones of both wrist-joints, in opposite directions, as in the case of O\u2019Neil : besides, the mere displacement of the bones of both forearms at the wrist-joint, constituted only a part of the abnormal state of things noticed, because both of the forearms were so short as to measure only half the length of the arm, and did not exceed in length the measurement of the long axis of the hand. The history of her case, then, from her birth \u2014 the negative evidence as to the existence of any previous accidental cause adequate to account for the appearances, and the actual abnormal condition of both the upper extremities of O\u2019Neil \u2014 all taken together, sufficiently proved her case to offer a curious specimen of congenital malformation of both wrist-joints and forearms.\u201d\nWhen the writer presented this case to the meeting of the Pathological Society, he laid before the members two casts of the malformed extremities of the patient, and when the drawing of Cruveilhier\u2019s case {pi. 2. liv. ix.), was placed along side of the cast of the right forearm of O\u2019Neil, every one present agreed in the opinion that the cast presented an exact counter-part of Cruveilhier\u2019s drawing (Jig- 924.).\nDeborah O'Neil, five years subsequently to this date, died suddenly of apoplexy, in the Government Asylum, Island Bridge. Dr. R W. Smith, the surgeon of the institution, made a post mortem examination of the affected articulations. The result fully proved, as had been anticipated, that her right wrist-joint in every respect resembled the remarkable case brought forward by Cruveilhier.\nPost Mortem Examination.\u2014Upon the 15th\nCase of O'Neil.\nof December, 1843, Mr. Smith exhibited before a meeting of the Dublin Pathological Society, the skeleton of the limb in this case.\nThe right extremity presented an example of luxation of the carpus forwards, while in the left was afforded an instance of displacement of the carpus backwards.\nRight Extremity. \u2014 The upper arm and hand, as already mentioned, bore a just proportion to each other, and to the stature of the individual, but the forearms were scarcely one half the usual length. The first range of the carpus was articulated with the anterior aspect of the radius, which bone was only\nFig. 927.\nSkeleton of Right Forearm.\tCase of O'Neil.\n(After Smith.)\nfour inches and a half in length (fig. 927.). The ulna, six inches in length, was prolonged below the radius nearly half an inch, its lower","page":1510},{"file":"p1511.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1511\nextremity was destitute of the rounded head, which in the normal state is received into the concavity of the radius, and was carried forwards outwards and upwards (see fig. 927.). About half an inch above the level of its lower extremity it was in contact with the radius by a very small surface which was destitute of cartilage. An anterior and posterior ligament connected the two bones in this situation, and permitted a very slight degree of motion between them. The lower extremity of the radius was totally destitute of articulating surface, and was represented by a rounded and blunt margin.\nThe surface for articulation with the carpus was placed altogether on the anterior aspect of the bone. It consisted of a deep excavation of an oblong form, and its longest diameter running somew'hat transversely ; it was tolerably smooth, though not invested with cartilage.\nThe radius and ulna were not only remarkably short, but likewise atrophied, both as to breadth and thickness.\nTheir superior extremities, with the exception of being unusually small, presented no abnormal appearance.\nThe bones of the first row of the carpus were in a state of atrophy, especially the semi-lunar bone. When the hand was flexed at a right angle with the forearm, the lower end of the ulna formed a most conspicuous projection, while during extension, two prominences were seen ; one, in front, caused by the carpus, the other posteriorly, marking the position of the lower extremities of the bones of the forearm. The hand was inclined to the radial side of the forearm ; it admitted of being flexed to a right angle, and could be extended perfectly. The extensor tendons in their passage from the forearm to the hand were lodged in deep and narrow grooves, or channels, formed on the dorsal aspect of the radius.\nUpon the left side the deformity was equally remarkable, although the reverse of that noticed on the right side. The carpus was received into a socket formed for it by the radius and ulna. This socket was not at the\nlowest extremity of the bones of the forearm but near to it, and on the dorsal aspect of the bones, and it presented somewhat a glenoid shape, the longest diameter of which was directed obliquely downwards and inwards. With respect to the carpus, there was neither a scaphoid nor semi-lunar bone. The hand placed in the state of extension formed a right angle with the forearm, but the patient had the power of bringing it to a straight line with the latter, in which position two prominences were seen ; but, contrary to what was observed on the opposite side, the dorsal projection was here formed by the carpus, the extremities of the radius and ulna constituting the palmar eminences (see fig. 927.). In this left extremity, the carpus and forearm, including the elbow joint, were malformed, as well as the wrist-joint, but the rest of the skeleton, with the exception of the right wrist-joint and forearm, was quite normal.\nCase III. \u2014 Case of congenital luxation of the wrist-joint of both bones of the left forearm backwards.\nThe writer exhibited to a meeting of the Surgical Society of Dublin, on March 20th, 184-7, the cast of the left forearm of an adult female, who had been born with a luxation of the carpal extremity of both the bones of the left forearm backwards. The lower extremities of the radius and ulna were placed completely on the dorsum of the carpus, while the hand was, consequently, situated in the front of these bones.\nThis remarkable cast of congenital luxation of the wrist-joint was sent across the Atlantic by Dr. R. MacDonnell, now holding, as a surgeon of the Montreal Hospital, a distinguished place in British America.\nWe observe that in the casts ( figs. 928. and 929., the representations of Dr. R. MacDon-nell\u2019s case), the hand is well formed, but that the forearm is much shorter than it should be, being very little longer than the hand ; the whole length of the forearm is not eight inches, while that of the hand, measured in its greatest length, amounts to six inches and one half. The forearm in its upper part is round and muscular ; as we examine it towards the hand,\nCongenital dislocation of both Bones of the Forearm backwards.\nit assumes a well marked quadrilateral form, and we observe a projection on the dorsum of the carpus posteriorly, obviously formed by the lower extremities of the radius and ulna, which are dislocated backwards. The lower extremity of the forearm at the wrist here exhibits a very oblique termination, the ulna\nhaving passed, by fully an inch, the carpal extremity of the radius.\nWhen we place the forearm on its palmar aspect, as on a table, and view the ulnar side of it, we notice that the ulna rides conspicuously on the back of the carpus, being above its level about an inch ; and at the\n5 D 4","page":1511},{"file":"p1512.txt","language":"en","ocr_en":"1512\nWRIST-JOINT (Abnormal Anatomy).\nsame time that the ulna has passed so far 929.). The radius at its lowest part, besides downwards on the back of the carpus as to being thus shorter than the ulna, is much less reach even to the upper extremity of the salient on the dorsum of the carpus, metacarpal bone of the little finger (see fig. The upper extremity of the carpus and the\nFig. 929.\nSecond view of the same deformity as Fig. 928.\nhand are placed, as has been mentioned, anteriorly to, and somewhat above, the lowest extremity of the radius and ulna, and consequently the measurement of the antero-pos-terior diameter of the wrist is much increased ; the whole forearm is somewhat bowed, presenting on its anterior aspect a concavity in the longitudinal direction. Near the wrist-joint the tendons of the flexor carpi ulnaris on the inner side, and of the flexor carpi ra-dialis on the outer, or radial side, are thrown into strong relief, and thus contribute to give the quadrilateral form to the wrist above alluded to.\nSince the writer made this communication to the Surgical Society of Dublin, he has seen other cases pf congenital luxation at the wrist-joint of both the bones of the forearm backwards on the dorsum of the carpus. They so strongly resembled the cases just now adduced, that he refrains from entering into particulars. From all these last mentioned, the individuals practically suffered little from the defect.\nFrom the cases the writer has seen or investigated, he may draw the following conclusions : \u2014\n1st. That the case of D. O\u2019Neil, brought before the Pathological Society of Dublin, Dec. 15th, 1838, by the writer, was the first example laid before the profession with the intention of proving that such a lesion as a congenital luxation of the wrist-joint existed.\n2nd. That Cruveilhier\u2019s case, adduced five years previously, as a case of an old unreduced luxation of the wrist-joint, and considered by Dupuytren as a fracture of the radius and dislocation of the ulna, and since misinterpreted by others, must hereafter be looked upon as an excellent example of congenital luxation of both the bones of the forearm backwards at the wrist-joint.\n3rd. That the case sent to Dublin by Dr. MacDonnell of Montreal, is another example of a congenital luxation of the bones of the fore-arm at the wrist-joint backwards.\n4th. In these three the humerus and hand seem to have borne, as to length and size, a normal proportion to the stature of the individuals; but the forearms in all three were so much shortened, as not to exceed by one inch the measurement of the long axis of the hand.\n5th. The lower extremity of the ulna in the three cases, instead of being on a level with the lower extremity of the radius, as it normally is, had passed lower down on the dorsum of the carpus from half an inch to one inch.\nBesides these three cases of congenital luxation of the bones of the forearm backward at the wrist-joint, Dr. R. Smith has, in his valuable work recently published, referred to two more specimens of the same malformation. A cast of one of these specimens was preserved in the Museum of the Bristol Infirmary, in August, 1836, when the writer and Dr. Smith visited that hospital, and the bones of the other specimen have been preserved in the Museum of the Richmond Hospital.\nThe case of O\u2019Neil presented in her left forearm the only example of which we have heard of congenital luxation of the bones of the forearm forwards {fig. 926.). In this case, also, it is to be remarked, that the forearm was preternaturally short.\nSince the above observations were written I have seen other examples of congenital luxations of the wrist, in which the bones of the forearm were displaced backwards, and the carpus forwards, as in figs. 924. and 925. Sometimes the defect was single, or only affected one forearm ; in others, the defect, if the paradoxical language be allowed, was symmetrical, affecting both wrists alike. A case of this last description was shown to me lately in the Downpatrick Infirmary, by the surgeon of the institution, Mr. Brabazon, who was kind enough to present me with a cast, which 1 have in my possession.* This healthy young woman is the mother of many well-formed children, and feels but little inconvenience from the malformation.\nWhen speaking of the congenital defects of the elbow-joint, we noticed that the upper extremity of the radius often exceeded its normal length, so as to reach as high as the level of the olecranon process. (See Elbow, Abnormal Condition of.) We may here remark, that the ulna as the result of congenital malformation, in almost all the specimens we have examined, of the congenital\n* This cast so much resembles that of fig. 929., that they could scarcely be supposed to have been taken from two different individuals.","page":1512},{"file":"p1513.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1513\nluxation of the wrist, has been at least half an inch lower down than the level of the carpal extremity of the radius. The reverse, however, of this I have lately seen, in a case of congenital luxation of the wrist, under Dr. M\u2018Dowel\u2019s care, in the Whitworth Hospital. In this case, of which Dr. Gordon has been kind enough to present me with a cast, the radius has, at its lower extremity, passed half an inch lower down on the back of the carpus than the ulna ; varieties have been also noticed as to the carpus ; in some cases the bones of the carpus were not only malformed, but deficient in number ; in one case nine bones were found.\nThere are other congenital malformations of the wrist-joint which demand some attention from the physician and surgeon, such as affections of the wrist analogous to valgus, and cases of the foot and ankle, but we do not consider this the place to discuss these cases.\nWe may make the same remark as to those congenital defects of the hand with deformity of the wrist, which have been noticed to coincide with a deficiency in the brain on the side opposite to the deformity.\nAccident. \u2014 The principal lesions which the structure that compose the region of the wrist are liable to, are : \u2014\n1st. Dislocations of the wrist and neighbouring radio-ulnar articulations.\n2nd. Dislocations of the bones of the carpus.\n3rd. Fractures of the lower extremities of the bones of the forearm, in the immediate vicinity of the wrist-joint.\n1st. Dislocations. \u2014 Dislocations and fractures of the bones entering into the composition of the wrist-joint are two kinds of lesions, which for a long time have been confounded together, or mistaken for each other. Even in modern times authors have stated the wrist-joint to be liable to numerous luxations. Thus, Boyer, Petit, Mr. Samuel Cooper, &c. &c., entered into a description of the different dislocations of the wrist, as forwards, backwards, imvards, and outwards, complete and incomplete, just as Hippocrates and others, down to Celsus, had done.\nNevertheless, some moderns, at the head of whom we would place Dr. Colles of Dublin, Dupuytren, and Sir Benjamin Brodie, maintained that luxations of the wrist-joint from accident were either impossible, or, at all events, exceedingly rare, and expressed their opinion that authors had, under the erroneous name of dislocation, really described an accident now pretty generally believed to be a fracture of the radius in the immediate vicinity of the wrist-joint, with displacement backwards of the carpus and hand.\nVelpeau followed these, and not only denied the reality of such an accident as simple dislocation of the w'rist, but gave his reasons why he believed that no such accident could occur, observing, that the strong tendons of the flexor muscles of the forearm, bound down by the anterior annular ligament of the\ncarpus, must render impossible any luxation of the bones of the forearm forwards at the wrist-joint, during any forcible bending backwards of the hand, such as might, for example, be produced by a fall on the palm ; and, 2ndly, that the common and radial extensor (restrained as they are by the posterior annular ligament), oppose any luxation of the bones of the forearm backwards at the wrist during a movement which should produce an extreme flexion of the hand forwards.\nVelpeau, however, admitted, that from experiments he had made on the dead subject, he had learned that efforts of a different order, such as a forcible pulling, accompanied with a simultaneous bending of the hand, whether backwards or forwards, inwards or outwards, might break every tissue, and produce a luxation without any fracture of the radius. Such cases, he says, he believes will always be accompanied with a wound of the integuments, and are not to be looked upon as the simple dislocations we are now considering, nor should they, in his opinion, enter into the same category with them.\nIn support of the doctrine, that most, if not all, of the simple dislocations of the wrist, of the authors already alluded to, were really fractures of the lower extremity of the radius, we confess that one observation of Velpeau appears particularly strong, viz., that for the last thirty or forty years in which the question has been discussed, and the reality of the luxation disputed, no one has brought forward one instance which, rigidly examined, he would look upon as an incontestable example of a simple luxation of the wrist-joint. He admits that the solitary case adduced by Voillemier is a very notable one, and deserving of attention, but that in his opinion, the question is still open as to whether a simple luxation of the wrist-joint can occur, without there being at the same time any lesion of the edges of the articular surfaces, or of the integuments.\nWe think we cannot do better than here give an abstract of this remarkable case, given by Voillemier.*\n\u201c Levillain Louis, \u00e6t. 27, of a vigorous constitution, on the 28th Sept. 1839, was admitted under the care of M. le Noris, into the H\u00f4pital des Cliniques (Paris) ; at the moment of admission he was in a hopeless state, completely insensible ; the pupils largely dilated, the respiration stertorous. Amongst other lesions from which the patient had. suffered, in consequence of his having fallen into a court-yard from a window three stories high, to the ground, it was noticed specially that the left wrist-joint presented a very remarkable deformity, and of such a nature that Voillemier, prejudiced as he said he felt he was, that a luxation of the wrist was a great rarity, if not an impossibility, could not help saying to his colleague, M. Dumeril, present at the examination of the patient, that the case be-\n* See Archives Generales de Medecine, Decemb. 1839, p. 400.","page":1513},{"file":"p1514.txt","language":"en","ocr_en":"1514\nWRIST-JOESTT (Abnormal Anatomy).\nfore them was one of dislocation of the wrist. Four hours after the admission of the patient into hospital he died.\n\u201c The forearm was semi-flexed as well as the hand. The bony plane represented by the metacarpus and the carpus was almost parallel to that of the forearm. The hand was neither adducted nor abduced, but had suffered a displacement \u201cde totalit\u00e9\u201d towards the internal side. At the posterior and inferior part of the forearm there was a saliency formed by the displaced carpus. A line drawn from the summit of this saliency to the 'phalangeal extremity of the metacarpal bone to the middle finger, measured three inches and seven lines, the same length which the uninjured carpus and metacarpus of the opposite side presented. At the inferior and anterior part of the forearm a, there existed a transverse eminence, situated about eight lines nearer to the extreme point of the fingers, than the posterior saliency B, while it projected anteriorly beyond the plane of the palmar surface of the hand, fully seven lines. The radii on both sides measured alike. The skin was abraded, and a wound about an inch long existed on the dorsal surface of the radius near the wrist, at about the level of the superior border of the pronator quadratus.\nLigaments.\u2014 The external lateral ligament and the posterior ligament were lacerated ; the anterior completely torn from the border of the radius. Some remnants of this structure lay on the front of the carpus. The internal lateral ligament was not torn, but the styloid process of the ulna, maintained by this ligament, and at the same time by the attachment of the sheath of the flexor carpi ulnaris, had been detached from the body of the bone. Thus all the means of union of the articulations had been completely severed, and the bones of the forearm were only held to the carpus by some bundles of fibres, which passed posteriorly from the triangular ligament to the internal side of the carpus.\nBones. \u2014 The radius did not present any trace of fracture ; the body of the ulna was also unbroken, but its styloid process was torn from the rest of the bone, although still held by ligament and tendon, as above mentioned. In the new position which the bones of the forearm had accidentally assumed, relatively to the carpus, they concealed and lay in front of the whole first range of carpal bones, and had been arrested in their descent only by the true annular ligament, and the tendons of those flexor muscles which pass behind this ligament.\u201d*\nLet us suppose now a transverse fracture of the radius, situated near to the wrist-joint, with the displacement backwards of the inferior fragment. This kind of accident will most simulate a luxation of the wrist, such as the foregoing case, in consequence of the size of the two eminences, the one placed anteriorly, the other posteriorly ; but in frac-\n* Archives G\u00e9n\u00e9rales de M\u00e9decine, Decemb. 1839, p. 401.\nture the anterior and posterior saliency, in general, are not very conspicuous ; while in luxation the posterior formed by the carpus, and the anterior by the bones of the forearm, have each a thickness of more than half an inch.\nIt is very true that we have seen cases (see fig. 933., for example) of fractures through the junction of the lower epipf^ses of the radius, with fracture also of the ulna, which even in this amount of saliency of the anterior and posterior prominency, much resembled the case of a dislocation ; but the saliency posteriorly in the case of the dislocation is formed only by the rounded summit of the carpus, and the measurement from this point to the ultimate extremity of the middle finger gives only the normal length of the hand ; whereas, if the deformity at the back of the forearm resulted from a fracture of the radius with displacement backwards of the lower fragment surmounting the carpus, a measurement taken from the summit of the dorsal prominence to the end of the middle finger would show an increase of at least half an inch over the normal length of the whole hand, because to the summit of the carpus in the case of fracture with displacement is superadded the amount of the depth of the lower fragment of the radius. By this test of measurement, therefore, we might settle our diagnosis between these two accidents which so much resemble each other.\nThe styloid process, too, of the radius can be felt still holding its normal relation to the carpus in cases of fracture, and to move with the hand when any motion is communicated to it ; whereas, in the rare dislocation of the wrist-joint, which we are here considering, the lower extremity of the radius and ulna will be found placed in front of the carpus, and here, too, form an abrupt swelling, just above the superior margin of the annular ligament of the wrist.\nDislocation of the bones of the forearm backwards with displacement forwards of the carpus.\n\u2014\tIt is said that this dislocation, which is the reverse of the foregoing case of Voillemier, may occur as the result of accident.* Upon this head all we have to say is, that this dislocation of the bones of th\u00e9 forearm backwards at the wrist-joint, as the result of accident, must be exceedingly rare ; but that, on the other hand, this is the very displacement of the bones which so usually exists in almost all cases of congenital dislocation of the wrist-joint (figs. 924. and 925.).\nLuxations of the lower extremity of the ulna.\n\u2014\tThere are two species of this luxation of the lower extremity of the ulna. In one, the ulna escapes from the sigmoid cavity of the radius in passing backwards ; in the other, it is by the anterior part of the articulation that the displacement occurs. Luxation of the inferior extremity of the ulna backwards is the more frequent of the two ; that forwards must be rare, says Boyer, for I have seen but one\n* See Nelaton, El\u00e9mens de Pathologie, vol. ii. p. 408.","page":1514},{"file":"p1515.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1515\nexample of it, and Dupuytren mentions that he has met with but two. Sir A. Cooper refers to only one case of dislocation of the lower extremity of the ulna. In this case the bone was thrown backwards.\nLuxation of the lower extremity of the ulna at the wrist-joint, backwards. \u2014 Desault has published the history of a washerwoman who had a luxation of the inferior extremity of the ulna backwards, in consequence of the violent and sudden pronation in which the wrist had been forced into while she was in the act of wringing clothes.\nIn this luxation, backwards, the forearm and hand are in a state of forced pronation, and the two bones are strongly crossed, forming with each other a very acute angle of decussation ; the inferior part of the forearm is much narrower than in the normal state ; the forearm, the hand, and the fingers, are maintained in a state of moderate flexion, but fixed ; the tendons of the flexor muscles of the finger are, as it were, matted together into a single fasciculus, displaced inwards, and form a sensible saliency upon the ulnar border of the radius.\nWhat strikes one most, in looking at the back part of the wrist, is the very manifest projection on the dorsum of the region, formed by the lower extremity of the ulna, which rises so much above the level of the back of the hand.\nLuxation forwards. \u2014 Desault, Boyer, and Dupuytren have each adverted to this dislocation, in which we observe an oblique crossing of the bones of the forearm ; the fingers are semiflexed, and there is a remarkable narrowness of the inferior part of the limb. The forearm and hand are fixed into a state of supination, the saliency of the ulna is perceived in front, the tendons of the flexor muscles are pushed outwards towards the radius, and the inferior part of the ulna, instead of being parallel to that of the radius, as in the normal state, is oblique from above downwards, from within outwards, and from behind forwards.\nBoyer gives the following remarkable example of this accident. In 1791, a woman of a strong constitution, and of a spare, though muscular frame, while in a state of intoxication, looking at two persons playing \u201cdomino\u201d in a caf\u00e9, in Paris, foolishly ventured some advice to the players, who besought her not to interrupt them. She, however, thought proper to persist in giving her gratuitous advice, until at last one of the players, a strong and vigorous man, got up in a very angry mood, seized her violently by the right hand and endeavoured to push her out of the room. In this movement her hand and forearm were carried suddenly into a state of preternatural supination. Immediately the woman experienced the most acute pain, and cried out that her wrist was broken. The pain, the deformity, and the impossibility she experienced of executing the ordinary movements of the forearm, made\nher fear that she was most seriously injured' \u201c I was called in,\u201d says Boyer, \u201c instantly, and I found the patient complaining of most acute suffering, having the forearm Hexed, the hand fixed in a forced state of supination. The least effort to communicate a movement of pronation caused the patient the most acute aggravation of her sufferings. The ulna formed a very sensible prominence anteriorly, and this bone, instead of being parallel to the radius, formed with it an acute angle, crossing its direction somewhat, and passing downwards, forwards, and outwards.\u201d All thes\u00eb symptoms taken together left no doubt on the mind of Boyer, but that the case he had to deal with was one of luxation foriuards of the lower extremity of the ulna. It was not until after having tried thrice unsuccessfully that at length he succeeded in reducing the dislocation.\nLuxations of the inferior extremity of the ulna forwards from the scaphoid cavity of the radius are, according to the opinion also of Dupuytren, excessively rare, at least, \u201c in the course of my long practice,\u201d he says, \u201c I have met with but two cases of this accident.\u201d One of these cases he gives us a detail of, as follows : \u2014 Case. M. Blot, an officer of the gendarmerie, set. 32, of a sanguine temperament and athletic constitution ; while on duty during the night, the horse upon which he was mounted took fright, reared up, and fell back with his rider. The latter was happy enough during the fall to disengage himself nearly from the animal, with the exception that his right arm was placed between the head of the horse and the ground, and thus received a violent shock. M. Blot, considering his forearm broken, applied to two surgeons, who, each in succession, recognised a dislocation of the ulna at the wrist, and each, also, failed in reducing the dislocation. M. Blot came to Paris, suffering much, and applied at the Hotel Dieu to Dupuytren, on 25th November. He then laboured under the following symptoms : \u2014 The forearm was much swollen ; the hand was in a median position between pronation and supination ; the inferior part of the forearm was deformed, rounded or rendered cylindrical near the wrist-joint by the diminution of its bilateral diameter\u2014a remarkable saliency existed within and in front, formed by the lower extremity of the ulna thrown forwards towards the palmar aspect\u2014behind, a remarkable depression replaced the accustomed prominency formed by the lower extremity of the ulna (la mall\u00e9ole interne) ; indeed, behind, a depression existed instead of the saliency ordinarily formed by the head of the ulna. If we followed with the fingers the ulna, from the elbow even to the hand, we perceived that this bone directed itself obliquely forwards and outwards in crossing and passing over the inferior part of the radius. The luxation of the radius forwards became then evident. There was no crepitation. The movements of pronation and supination were completely lost. Du-","page":1515},{"file":"p1516.txt","language":"en","ocr_en":"1516\nWRIST-JOINT (Abnormal Anatomy).\npuytren having failed at the first attempt, he succeeded in reducing the luxation by inclining the hand forcibly to the radial side, and pushing with his two thumbs, united the displaced extremity of the ulna inwards and backwards. By this process the reduction was affected. The patient cried out at once, \u201c I am well.\u201d All deformity had disappeared, and the motion of pronation and supination were restored. (Gazette Medical, Malgaigtie.)\nSuch cases as these, says Dupuytren, ought to be recorded by every surgeon when he meets with them, in consequence of their rarity and importance.\nLuxation of the bones of the carpus. \u2014 The bones of the carpus are united to each other so solidly, and their movements are so limited, that without experience, we should be disposed to pronounce luxation of any of these bones impossible. Nevertheless, the head of the os magnum may be dislocated from the cavity formed for it by the scaphoid and semilunar bones. The first range of the bones of the carpus is articulated with the bones of the second range in such a manner that slight eliding movements of flexion and extension of the hand are permitted, which augment a little the movements of flexion aud extension of the hand upon the forearm, and add somewhat, as Cruveilhier says, to the grace of the movements of this portion of the upper extremity. In flexion, the head of the os magnum, which is somewhat inclined backwards, raises up the thin capsule which surrounds its articulation, and if this movement be carried very far, the capsule and accessory fibres which support the bone posteriorly are broken, and the os magnum escapes from the cavity in which it is naturally placed ; the dislocation cannot be called complete, yet the os magnum passes somewhat the level of the posterior surface of the other bones of the carpus.\nThe accident is more common in women than in men, no doubt because the ligaments are weaker and the bones enjoy greater motion in the former, than in the latter. The luxation backwards of the os magnum, the only one which can occur, is always the result of a forced and violent flexion of the wrist, such, for example, as a fall on the back of the hand would produce. We recognise the luxation of the os magnum by the history of the accident, and by the deformity produced. We perceive a hard, circumscribed tumour, which has suddenly appeared on the back of the hand, in the situation which corresponds to the head of the bone. This tumour becomes more prominent when the hand is flexed, and diminishes when it is extended : we can make it disappear entirely by a slight compression. This luxation causes but little inconvenience ; but the head of the os magnum always remains more salient when the hand is flexed, and forms a tumour, more or less marked, accord-ins: to the extent of the displacement.\nWe can easily reduce this luxation by extending the hand, or by exercising a slight pressure on the head of the os magnum ; but,\nalthough it is easy to make the bone resume its position in the cavity formed for it by the scaphoid and semi-lunar bones, it is very difficult to maintain it there, and the inconvenience and deformity resulting from the luxation are so trivial, that few persons will submit with patience to the means usually recommended.\nFractures of the lower extremity of the radius in the immediate vicinity of the wrist-joint.\u2014 We believe that the first important effort to direct attention to the peculiarities which the fracture of the lower extremity of the radius presents, was made by the late professor of surgery, of the College of Surgeons, in Dublin, Dr. A. Colles, in the year 1814.* Subsequently, we find Sir A. Cooper, in London, and Dupuytren, in Paris, each pointing out the importance, in a practical point of view, of our studying this accident, and distinguishing the case of fracture of the radius with displacement backwards of the carpus, from true dislocation backwards of the hand at the wrist-joint.\nVelpeau followed these, concurring with them in the opinion that a transverse fracture of the lower extremity of the radius was a very common injury, and frequently mistaken for a dislocation. He seemed to be even more positive than his predecessors in maintaining the doctrine that no accidental luxation of the wrist-joint could occur without a fracture of some of the bony processes, or laceration of the integuments.\nThis fracture is rarely attributable to any direct cause ; it appears, however, that Hub-lier communicated to the Academy of Medicine the case of a young girl, who having had the wrist caught between the pole of a carriage and a wall, had gotten a transverse fracture of the lower extremity of the radius. In this case there was combined with the above mentioned transverse fracture, another vertical one at right angles with it, dividing into two the lower fragment, constituting what in other articulations we have elsewhere in this book (vide Knee, Elbow) denominated a T fracture. This species of fracture by direct violence, corresponds much to the cases described by Dupuytren as \u201cFracture par \u00e9crasement.\u201d Fractures of the radius may be caused by falls on the back of the hand, but by far the most frequent sources of the fracture in question are falls on the palm.\nMalgaigne asks, by what mechanism are these fractures of the lower extremity of the radius specially produced. In reply he adduces the following experiment by Nelaton : \u2014 The latter amputated the forearm of a dead body at the elbow, and cut off the olecronon at a level with the head of the radius. He then applied the palm of the hand of the subject on a solid plane, the forearm being at the same time directed vertically ; he now with a mallet struck a heavy blow directly on the superior extremity of the two bones of\n* Vide Edinb. Med. and Surgical Journal, vol. x. 1814.","page":1516},{"file":"p1517.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy),\t1517\nthe forearm. The wrist broke and became immediately deformed. The dissection revealed a simple and transverse fracture of the carpal extremity of the radius, with a displacement backwards of the lower fragment, as with ordinary cases of fracture of the radius in the immediate vicinity of the wrist-joint, a species of injury, which in this city is known by the name of\u201c Colles\u2019 fracture.\u201d\nIt would also appear to Malgaigne, Bouchet, and Voillemier, that this fracture may be the result of a sudden and violent flexion of the hand without the patient having had any fall. This fact was first established by Bouchet, who, in endeavouring to produce dislocation of the wrist on the dead body, only caused in his experiments fractures of the inferior extremity of the radius ; sometimes with other disorders, and more particularly with a simultaneous fracture of the styloid process of the ulna.\nSymptoms. \u2014 If Colles\u2019 fracture of the radius be produced by a fall, the patient will,\nFig.\nsometimes, be able to say that at the moment of the accident he felt a sensation of something having given way near to the wrist-joint. The inferior extremity of the forearm and the hand swell ; the fingers are semi-flexed, and the patient experiences the greatest difficulty in performing the ordinary movements of the hand, or forearm. He usually presents himself to us with the hand of the injured forearm resting on its ulnar margin, and supported by the other hand, and in a middle state between pronation and supination.\nThe posterior surface of the forearm usually represents a considerable deformity; for a depression is seen to exist about one inch above the line of the wrist-joint, whilst a considerable swelling occupies the wrist itself and metacarpus ; indeed, the carpus and base of the metacarpus, appear to be thrown backwards so much, as at first view to excite a suspicion that the radius had been dislocated forwards, and the carpus and hand back-\n930.\n\u201c Colles\u2019 Fracture.\u201d\nwards (fig. 930.). On viewing the anterior surface of the limb we observe a considerable fulness, as if caused by the flexor tendons being thrown forwards ; this fulness extends upwards, to about one-third of the length of the forearm, and terminates below at the upper edge of the annular ligament of the wrist.\nThe inferior fragment of the radius being salient posteriorly, while the superior is thrown forwards, the injured forearm, viewed side-ways, resembles, in the undulating direction of its long axis, the outline, according to Velpeau\u2019s idea, of a silver dinner-fork. Besides presenting this very striking deformity, in this fracture we find the hand occasionally thrown outwards, or towards the radial side, and then the carpal extremity of the ulna presents a strong saliency internallv. The degree, however, in which this projection towards the inner edge of the wrist takes place, will be found to vary.\nThe patient is unwilling to attempt to pro-nate or supinate his hand, and if we endeavour to communicate such movements, much pain is produced. There is considerable pain felt by the patient when we press firmly with the point of the finger in the exact situation of the fracture.\nThe internal lateral ligament of the wrist-\njoint is generally put upon the stretch, and the patient usually complains of much distress here ; but this pain, which some patients feel about the lower extremity of the ulna, does not always arise simply from a sprain coincident with the fracture or from a rupture of the internal lateral ligament of the articulation of the carpus with the forearm, but we believe sometimes is owing to a fracture of the root of the styloid process of the ulna.\nIt is in this last case more particularly that the hand \u201c par un mouvement de totalit\u00e9,\u201d is carried outwards, and that the ulna seems very salient, internally (fig. 931.).\nA narrowing of the region of the wrist, in the transverse direction, has been much adverted to by Dupuytren, as a symptom of the fracture we are now considering, but we believe this narrowing is, in general, more apparent than real. We rather concur with Velpeau, who says, \u201c Many observations have induced me to believe that Dupuytren, and others, have been deceived as to the supposed narrowing of the wrist.\u201d He adds, an interosseous space, in reality, does not exist near to the wrist joint; indeed, there is scarcely any open interval to be seen between the lower extremity of the radius and ulna for the space of one inch above the line of the radiocarpal articulation. Now, fractures ordinarily","page":1517},{"file":"p1518.txt","language":"en","ocr_en":"1518\tWRIST-JOINT (Abnormal Anatomy).\ntake place at a point which is below the level of this line, and any displacement, the result of fracture, cannot readily affect the breadth of the interosseous space, placed above the line of the fracture.\nFig. 931.\nIt is only in cases where the fracture is situated so high as an inch and a half, or more, above the joint, that any abnormal approximation of the bones towards each other, and ultimate obliteration of the interosseous interval is to be dreaded.\nAlthough therefore, as a result of Colles\u2019 fracture, we observe the forearm assume, near the wrist-joint, a cylindroidal form, there may be no real narrowing whatever, but the appearance of it may be attributed rather to an increase, in the antero-posterior diameter of the region of the wrist, than to any real diminution which occurs transversely.\nMalgaigne has, however, adduced an example to explain how, in certain rare cases, a diminution of the transverse diameter of the forearm may occasionally take place, and by the action of the pronator quadratus not on the inferior, but on the upper fragment of the radius, (fig. 932.)\nIt is said by some, that crepitation, caused by the movements of the fragments of the broken radius on each other, can always be elicited, and that this sign is diagnostic of fracture ; moreover, that the deformity is easy to reduce by extension, but liable to return when the extending force is removed. Such observations, no doubt, may sometimes be made with truth. For our own parts, we do not think that crepitation can, except in a very few cases, be elicited in Colles fracture of the radius. We have found it to be an injury attended with a deformity which can, it is true, be removed by extension, but our experience corresponds with that of Sir A.\nCooper, who asserts that in this fracture a very powerful extension is required to bring the broken ends of the radius into apposition.\nAfter Malgaigne.\nDiagnosis,\u2014 In many cases, a fracture of the radius in the immediate vicinity of the wrist-joint is attended with so much deformity, and accompanied with such characteristic appearances, that the observation of Pouteau appears well founded, that it can be recognised at the first \u201ccoup d\u2019\u0153il;\u201d but on the other hand, there are some cases in which very little external evidence of any fracture can, without careful examination, be detected. The undulating curve, which has been compared to that represented by a silver fork, cannot exist without fracture, and the elevation from the level of the back part of the radius of the common extensor tendons is another feature, which we believe with Velpeau to be peculiar to fracture ; we know that in the normal state the tendons of the extensor carpi radialis longior and brevior remain applied as longitudinal bands, lying flat on the posterior surface of the radius, and no interval whatever exists between these two bands and the back part of this bone near to the wrist. Now, when there is a fracture of the radius here, this bone is rendered somewhat concave on its posterior surface, and these tendons must, of necessity, abandon the bony surface, and be raised up several lines from it, so as to represent a cord, more or less tense, but easy to depress. If, for example, the hand of the patient being a little flexed, the surgeon in examining these cases, places his finger or thumb three or four lines above the level of the wrist-joint, on the posterior surface, and near to the external border of the radius, he will, if fracture exist, recognise beneath the","page":1518},{"file":"p1519.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy''.\t1519\nskin the tense cord, and perceive that it can be depressed even to the posterior surface of the radius, from which it had been manifestly elevated. This last is a test upon which Velpeau specially relies.\nUpon the subject of Diagnosis of this fracture of the carpal end of the radius, Dr. Colles remarks, \u2014 \u201c the facility with which the surgeon can move the ulna backwards and forwards, does not furnish him with any useful help in his diagnosis as to the true notion of the injury. Moreover, when he moves his fingers along the anterior surface of the radius, he finds it more full and prominent than is natural ; a similar examination of the posterior surface of this bone, induces him to think that a depression exists about an inch and one half above its carpal extremity. He now may expect to find satisfactory proofs of a fracture of the radius at this spot. For this purpose he attempts to move the broken pieces of the bone in opposite directions, but, the patient is by this examination subjected to considerable pain, yet neither crepitus, nor a yielding of the bone at the seat of fracture, nor any other positive evidence of the existence of such an injury is thereby obtained. At last,\u201d adds Dr. Colles, \u201c after many unsuccessful trials, I hit upon the following simple method of examination, by which I was enabled to ascertain that the symptoms above enumerated actually arose from a fracture of the lower extremity of the radius : \u2014 let the surgeon apply the fingers of one hand to the seat of the suspected fracture, and locking the other hand in that of the patient, make a moderate extension, until he observes the limb restored to its natural form. As soon as this is affected, let him move the patient\u2019s hand backward and forward, and he will, at every such attempt, be sensible to a yielding of the fractured end of the bone, and this to such a degree as to remove all doubt from his mind.\u201d\nI have already stated that sometimes the fracture may exist without being accompanied by any appreciable displacement of the bones. The patient complains of a severe pain in the region of the wrist, when pressure is made on the broken part, and also when the forearm is moved. These are the only symptoms which exist, (if we except a slight swelling, particularly observable on the anterior surface of the wrist,) so that one would be tempted to believe that there was only a simple sprain existing. If, however, we make pressure on the line of the articulation, we do not cause the patient any pain, which we should do, if the symptoms arose from a sprain, while if the same degree of pressure be made a few lines above the joint, the pain is very severely felt. Now, if we place a thumb on the radius behind, in the presumed seat of fracture, and make the effort to bend the wrist at this part, so as it were to make the forearm here form an angle on itself, salient anteriorly ; if the angle be thus formed, we hereby obtain a pathognomonic sign of the fracture ; and a comparison of the two wrists submitted\nequally to this experiment, puts the matter beyond all doubt.*\nFractures of the lower extremity of the radius are generally looked upon as serious injuries. If this fracture has been mistaken for a sprain, or luxation, or abandoned to nature, according to Dupuytren, very serious changes ensue. \u201c The forearm, in the region of the wrist, instead of presenting a surface flattened anteriorly, will assume a cylindroidal form. The movement of pronation and supination will be lost, an cedematous swelling of the soft parts will continue ; the articulation remains immovable for a considerable time, and, if a rupture of the lateral ligament of the inferior radio-cubital articulation, or fracture of the styloid process of the ulna be superadded to the fracture of the lower extremity of the radius, we may see continue for life the abnoi'mal mobility of the two bones on each other.\u201d Mr. Diday, of Paris, has gone further, and asserted that these consequences of fracture of the radius, above alluded to, are often observed, in spite of all kinds of treatment, and of bandages, which modern surgery has suggested.\nIn making an estimate, as to the amount of evil resulting from the fracture of the lower extremity of the radius and its usual con-sequences, we find authors differ. Velpeau would seem to attribute many of the evils alluded to by Dupuytren rather to improper bandages, and the manner of treating the injury, than to anything in the nature of the accident itself.\nAlthough written so many years ago, the opinion of Dr. Colles, as to the prognosis in these cases, seems to us nearer the truth than any of the above mentioned conflicting observations of the authors alluded to.\nDr. Colles remarks, \u201c that should the case be treated as a case of sprain, and the fracture left unreduced, the practitioner will find, after a lapse of time, sufficient for removing similar swellings, that the deformity is undiminished. By such mistakes the patient is doomed to endure for many months considerable stiffness, and lameness of the limb, accompanied by severe pains, in attempting to bend the hand and fingers ; one consolation only remains, the limb will, at some future period, again enjoy perfect freedom in all its motions, and be completely exempt from pain, the deformity will, however, remain undiminished through life.\u201d\nUpon the whole, then, we may safely say, that when the fracture we have been describing has nothing unusual in it, and is only accompanied with the ordinary displacement backwards of the inferior fragment, that the case generally proceeds favourably.\nIf the true nature of the accident has been early recognised, and proper and sufficient extension made of the forearm, the peculiar characteristic curve disappears, not to return ; the fingers are found to be much more free in their movements, and can be more fully\n* See Colles and Malgaigne.","page":1519},{"file":"p1520.txt","language":"en","ocr_en":"1520\tWRIST-JOINT (Abnormal Anatomy).\nextended than before ; the pain disappears, and in about a month after the fracture has occured, if judicious treatment be adopted, the union of the fragments is so perfect, that the passive motion to restore the joints to their primitive suppleness may be commenced.\nNotwithstanding, therefore, the opinions of Dupuytren, Diday, &c., &c., we think that, as a general rule, in the case of Colles\u2019 fracture the prognosis is favourable.\nIt may be otherwise, if the styloid process of the radius be elevated much above its natural level, if the hand has quitted, partially, the lower end of the ulna, so as to be carried \u201c par un mouvement de totalit\u00e9 \u201d\noutwards, and if the case has not been early recognised.\nAnatomical characters of the Fracture\u2014On dissection, it will be found that the hard swelling which occupies the back part of the hand and wrist, is caused by the displacement backwards of the lower fragment of the radius, and the carpus carried with it in this direction. As a consequence of the altered direction of the radius, we find that the aspect of the carpal articular surface of this bone is altered, and instead of being directed, as it normally is *, downwards and somewhat forwards, it is now directed downwards and backwards (fig. 933.) ; the carpus and metacarpus retaining\ntheir connexion with the broken radius must always thus follow this bone in its derangements, and cause the characteristic dorsal convexity above alluded to. The change of direction of the articular surface of the radius is well shown by measuring the length of the broken radius in these cases, both on the palmar and dorsal aspect of this bone longitudinally, when it will be found that in Colles\u2019 fracture, the posterior measurement js several lines less than the anterior, which is exactly the reverse of what this measurement normally should be.\nWe dwell upon this abnormal ob\u2019iquity of the lower articular surface of the radius, for in the treatment of this injury it should be our principal aim to remedy this obliquity, and, as it were, reverse it, and thus make the aspect of the articular surface look as it should normally do, downwards and forwards.\nThe change of direction of the articular surface is caused by the extensor muscles of the carpus, and of the thumb, and by their tendons, which pass along the posterior surface of the radius in sheaths, firmly connected with the inferior extremity ot this bone, to which deviation in the direction of the lower fragment the action of the supinator longus muscle and its tendons may also somewhat contribute.\nProfessor Smith, who has investigated laboriously the anatomy of the bones in this injury, says he has discovered nothing to invalidate the truth ot\u2018 the general proposition first maintained by Voillemier, namely, that when the radius is broken within an inch of its lower extremity, the direction of the fracture is usually transverse ; but we find that he differs entirely from this last-named author upon the doctrine of the fracture of the radius in question, being one by impaction. It is very true, he says, that in every instance of the ordinary\nfracture of the carpal extremity of the radius, which he had an opportunity of examining anatomically long after the occurrence of the injury, he found upon making a section of the bone, from before backwards, a line of compact tissue continuous with the posterior wall of the shaft, extending to a greater or less distance into the reticular texture of the lower fragment; but he cannot agree with Voillemier, that this appearance affords evidence of impaction of the upper fragment into the lower. In the only recent specimen Mr. Smith had an opportunity of examining, the lower fragment was displaced backwards, the superior projecting one-eighth of an inch in front of it. There was no impaction whatever in this recent specimen, of either fragment into the other, nor any line of compact structure penetrating the reticular tissue of the lower fragment.\nIf the doctrine of impaction were true, the shortening of the radius in cases of fracture of its lower extremity, should be much greater than it ever is, for there is a second cause of shortening in operation, i. e. the alteration in the direction of the articulating surface, in consequence of which the posterior surface of the radius (naturally longer than the anterior) becomes the shorter of the two. Now, if to the degree of shortening produced by this cause we add that arising from impaction, we should have an amount of shortening much greater than ever occurs in the case of Colles\u2019 fracture ; indeed, after adducing other arguments against the theory of Voillemier, as to this being a case of fracture by \u201c penetration,\u201d Mr. Smith further remarks, that as long as the ulna remains unbroken and the ligamentous connexion between the two bones uninjured, it is scarcely possible for either fragment to\n* We always take it as understood that the patient is in the erect posture.","page":1520},{"file":"p1521.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1521\npenetrate the other, even to the extent of half an inch.\nWe agree with Velpeau, Smith, &c., in thinking that in this injury, Colles\u2019 fracture, there is scarcely any diminution of the transverse diameter of the forearm. The cylin-droidal form which the arm acquires being owing partly to an effusion among the flexor tendons, but principally to the increase of the antero-posterior diameter of the forearm at the seat of the fracture, consequent on the backward displacement of the lower fragment.\nI have never seen the case, spoken of by many, of transverse fracture of the radius, with displacement forwards of the hand and lower fragment, which accident is said to be produced by a fall on the back of the hand.\nFracture of the lower extremity of the Ulna. \u2014 A fracture of the lower extremity of the ulna is rather a rare accident, because, perhaps, of the great elasticity of this long and slender bone, and the mobility of its lower end, by which it, as it were, eludes the force which might otherwise cause its fracture. Indeed the ulna, it will be recollected, is not directly connected with the hand as the radius, the \u201c manubrium manus,\u201d is : and hence, when a patient falls on the palm of the hand, the whole force of the weight and impulse are sustained by the radius ; but if this last bone gives way, and a transverse fracture occurs, with displacement backwards of the hand and lower fragment, then, as a secondary consequence, a fracture of the ulna, near the wrist-joint, may follow. In the vast majority of cases, however, of fracture of the radius close to the wrist, which occur, for example, in Colles\u2019 fracture, the ulna remains unbroken.\nFracture of the lower extremity of the ulna may also be the effect of direct violence.\nWhen the ulna is broken alone, without being accompanied by any simultaneous fracture of the radius, it may be recognised by the pain felt by the patient when direct pressure is made on the broken part of the ulna, and by the difficulty he experiences whenever he attempts to pronate or supinate the forearm. When the surgeon takes hold of the lower fragment of the ulna, and moves it backwards and forwards, crepitation can be felt.\nFracture of the lower extremity of the ulna is an accident which requires much attention from the surgeon, as sometimes, if the separated fragment be small, as, for example, consisting merely of the styloid process of the ulna, no union may occur, and permanent weakness of the wrist-joint may follow.\nDisjunction of the lower Epiphysis of the Radius.\u2014 This must be considered rather a rare accident ; it is, however, occasionally to be met with ; and the history of the art of surgery furnishes us with well-marked examples of it, as the three following cases sufficiently prove : \u2014\nCase 1. \u2014\u201cI have,\u201d says Cloquet, \u201cobserved one case of the disjunction of the lower epiphysis of the radius, in a young lad twelve years of age, who fell from a considerable height from a tree to the ground.\nVOL. iv.\nBesides the injury done to the radius, he received, at the time of the fall, a wound of the head which in three days proved fatal to him.\u201d\nDissection. \u2014 The epiphysis of the right radius was entirely separated, and a great quantity of blood was effused in the deeper palmar region, behind the tendons of the deep flexor muscles of the fingers (Diction, de M\u00e9decine, 1824).\nCase 2. \u2014 Rognetta has adduced a similar case of a lad at fifteen years (Gazette M\u00e9dicale, 1834.).\nCase 3. \u2014 In December 15th, 1838, the writer laid a case before the Pathological Society of Dublin, which was a true specimen of a disjunction of the lower epiphysis of the radius.\nThe patient, having been above eighteen years of age, had attained to a more mature time of life than any other example of this special injury affecting the wrist hitherto recorded ; a representation of the external appearance which the lower part of the forearm and carpus presented in this case have been preserved by a plaster cast ; and after the death of the patient, the actual condition of the parts having been ascertained anatomically, these circumstances, in the writer\u2019s opinion, make this case valuable.\n\u00c0. B., set. eighteen, a mason, fell from a scaffold w hich was attached to the front of a lofty house at its third story. By the fall he received a severe injury of the head, which rendered him immediately insensible, and in this condition was admitted into the Richmond Hospital. Besides the injury of the head, we noticed in this case a remarkable lesion ; the right wrist had suffered a derangement, accompanied with a deformity that at first sight we might suppose would be produced by a dislocation of the carpus and hand backwards on the dorsum of the forearm (fig. 931.). The plane of the hand and carpus were placed fully three quarters of an inch behind the plane of the rest of the forearm ; and from the external appearances there seemed no doubt but that there was an abrupt transverse solution of continuity of the forearm, close to the wrist-joint, which equally affected both radius and ulna.\nOn viewing the limb laterally, the peculiar curve which Velpeau compared to the back of a silver dinner fork, was exaggerated beyond what we noticed in the ordinary fracture of the radius in this situation; and the tendons of the extensors, particularly those of the extensor carpi, were thrown remarkably into relief. The anterior, or palmar surface of the forearm presented a longer and more uniform curve than the posterior ; the depth of the antero-posterior diameter of the wrist in the seat of injury was much increased : so that this and the bilateral measurement seemed equal.\nThus the accident presented many of the appearances of the dislocation, backwards, of the hand and carpus ; but the longitudinal measurement, taken from the highest part of\n5 E","page":1521},{"file":"p1522.txt","language":"en","ocr_en":"1522\tWRIST-JOINT (Abnormal Anatomy).\nthe dorsal prominence to the root of the in- inch over that of the opposite hand. This dex finger (from A to Bfig. 934.), on the in- excess of length was manifestly caused by jured side, gave an excess of length of half an the presence of the disjoined epiphysis, which\nFig. 934.\nDisjunction of the Epiphysis of the Radius, with displacement backwards of the Hand and Carpus,\n\u2014 Author\u2019s Collection.\nhad been superadded to the summit of the carpus, and was carried back with it, the wrist-joint itself remaining perfect.\nThis simple test of the comparative measurement proved the case was not one of mere dislocation of the hand ; but we may also add, that, although there was considerable swelling and projection forwards of the palmar surface of the region of the wrist, there were not those hard protuberances to be felt in front of the carpus which the extremity of the radius and ulna, with their styloid processes, should have presented had the dislocation above alluded to occurred.\nThe man died, in a few hours after admission, from the injuries he received, particularly of the head.\nIt had not been deemed advisable to reduce the fracture, as the man seemed to be in a dy\u00eeon, state.\nDissection. \u2014 With the assistance of my friend, Dr. Power (now Professor of Anatomy of the Royal College of Surgeons, Dublin), I removed the greater part of the forearm, that we might the more carefully examine the true nature of the lesion, the external appearances of which we have above described.\nOn making, then, the anatomical examination of the parts composing the region of the wrist in this case the radius was found to have suffered a transverse interruption of continuity in the line of junction of its inferior epiphysis, and the lower fragment was displaced directly backwards, so far as nearly to have passed the extremity of the upper fragment {fig. 935.). The lower extremit}' of the ulna was broken a short distance above the line of junction with its epiphysis. This fracture was oblique. The extremities of the two fragments of the ulna formed with each other an angle salient in front. The ligaments and the radio-carpal articulation also remained uninjured, and the carpus (of course) accompanied the lower fragment of the radius in its displacement backwards.\nCase 4.\u2014 A boy, set. eleven, was admitted into the Richmond Hospital on the 2nd of September, 1840, under the care of Dr. Mac-donnell. Upon the Sunday previous to his\nadmission he had been thrown from a horse with great violence. The lower extremity of the left radius was broken, and he sustained a\nFig. 935.\nDisjunction of the Lower Epiphysis of the Radius, with fracture of the Ulna, and displacement backwards of the Carpus and Hand. \u2014 Museum of the Richmond Hospital.\nconcussion of the brain, under the influence of which he remained insensible for three quarters of an hour. The accident occurred at some distance from town. Before an hour elapsed the boy was visited by a surgeon, who, it is said, forcibly extended the limb, and then applied a narrow roller tightly round the wrist. On the following day (Monday) the patient","page":1522},{"file":"p1523.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1523\ncomplained of intense pain in the limb ; the hand became cold and discoloured ; the roller was not removed nor relaxed. On Tuesday, dark coloured vesicles formed ; constitutional symptoms of the gangrene showed themselves; the pulse 159, feeble; countenance anxious. The gangrene increased for two days more, and reached within two inches of the elbow-joint. On the sixth day a line of separation showed itself; and on the twenty-fourth day the bones were sawn through, and the wound soon healed.\nDissection of amputated Forearm. \u2014 The radius was found to have been completely broken through in the line of junction with its lower epiphysis. The ulna was entire. The preparation of the disjoined epiphysis and gangrened hand is preserved in the Museum of the Richmond Hospital.\nThe causes which have been known to produce a disjunction of the epiphysis are said to be similar to those which produce a transverse fracture of the bone close to the wrist-joint: but why in one case we should have a fracture, and in another a disjunction of the epiphysis, we cannot say. All my own observation has, as yet, taught me relative to this subject from the cases I have seen and inquired into, has been that the cause producing the disjunction in question has always been a violent one.\nWhen a patient has suffered a disjunction of the lower epiphysis of the radius, there is, in general, much deformity observable in the region of the wrist. The hand, carpus, and lower fragment are carried backwards, and form together a plane which is from half an inch to three quarters of an inch behind the plane of the back part of the rest of the forearm ; the transverse line of elevation of the lower fragment above the level of the dorsum of the upper fragment of the radius is very abrupt and obvious : and the first impression on the mind is, that a dislocation backwards of the carpus and hand is the accident which has occurred. This abrupt transverse ridge and depression are crossed vertically by the extensor tendons of the carpus; and pressure with the fingers discovers these longitudinal tendinous bands to be on the stretch, having been forcibly elevated from the back part of the radius as they pass to their grooves formed in the lower fragment.\nThe palmar surface of the forearm is unusually convex from above downwards, and does not present a salient angle in front, such as we might expect from the abrupt depression we noticed on the dorsum of the wrist and forearm. This convexity of the forearm in front, however, abruptly terminates in a transverse narrow sulcus which marks the situation of the upper margin of the anterior annular ligament. The radial margin of the forearm is concave, and the ulnar margin presents a corresponding convexity. The patient complains much of pain, and has the same inability to move the forearm and hand as in cases of fracture.\nBy the above-mentioned signs we become informed that a solution of continuity in or\nnear to the transverse line of junction of the lower epiphysis of the radius exists : but without having had any opportunity of instituting an anatomical examination, we believe it would be difficult for any one to affirm whether the case were one of fracture, or disjunction of the epiphysis. Some writers seem to think that the case of disjunction of the epiphysis may be recognised by the circumstance, that, although there is an evident solution of continuity in the line of the radius, the crepitus of an ordinary fracture cannot be produced. To which we reply, that the absence of crepitation is not by any means unusual in cases of fracture of the radius in the region of the wrist; and, therefore, from this observation no useful inference can be deduced to aid our diagnosis.\nIn the examples of disjunction we have seen, we have always noticed a fixed condition, as it were, from the interlocking with each other of the portions of the disjoined radius ; so that it seemed quite vain to seek for crepitus ; \u2014indeed we found it invariably demanded a considerable force in these cases to restore the limb to its original form.\nWe believe it is impossible to make a differential diagnosis entirely to be relied on in these cases ; but we may, we think, conjecture that the disjunction in question exists rather than a fracture, when the age of the patient is under eighteen or nineteen years, and the situation of the solution of continuity is in the exact transverse line of the junction of the epiphysis to the shaft of the bone. If, however, the diagnosis be difficult, we have practically little to regret this circumstance, because the prognosis and the-treatment will be the same in both cases.\nSection 111. Disease. \u2014 In describing the alterations, the result of disease as \u2018 affects the other articulations, the abnormal anatomy of which we have already adverted to in this work, we have classed these morbid changes into those which are the consequence,\n1st. Of Acute Arthritis.\n2nd. Of Strumous Arthritis ; that is to say, \u201c a scrofulous disease of the joints, having its origin in the cancellous structure of the bones.\u201d\n3rd. Of Chronic Rheumatic Arthritis.\nHere we may adopt a similar arrangement, but shall find it necessary to add,\u2014\n4thly. A few observations on Synovial Tumours of the Region of the Wrist.\nAcute Arthritis of the radio-carpal, and of the inter-carpal articulations, may be the consequence of a contusion or a wound, or it may originate in some internal cause, such as an acute rheumatic, or a diffuse inflammation.\nAcute arthritis of any or all the joints which enter into the composition of the region of the wrist may be the consequence of a sprain or wound, or the inflammatory action may have been communicated to these joints by having extended along an injured tendon of the finger, or the inflammation, suddenly showing itself in the joints, may have originated in some unknown internal causes, such as those which\n5 e 2","page":1523},{"file":"p1524.txt","language":"en","ocr_en":"1524\tWRIST-JOINT (Abnormal Anatomy).\npreside over the development of an attack of an acute rheumatic arthritis, or of diffuse inflammation.\nWhatever ma) have been the specific nature of the acute inflammation, there is soon noticed, besides the pain felt through the carpal region and the heat, that there is considerable swelling. This last is more particularly observed on the dorsum of the wrist and carpus than elsewhere. An effusion, whether of serum or pus, very soon takes place into the interior of the synovial sac, which will always have a tendency to distend this sac in all directions ; but there can appear but little swelling at the anterior part of the articulation, because here a large fasciculus of flexor tendons of the fingers passes, and supports the synovial membrane. On the lateral aspect of the wrist-joint, the tumefaction, although sensible, is still limited by the resistance which the lateral ligaments oppose to the distension of the capsule. Behind, on the contrary, where the synovial membrane is unsupported and but superficially covered, the swelling, the result of the inflammation, soon becomes much more manifest, and fluctuation evident.\nWe are not aware of any case recorded in which complete dislocation of the hand, on the back part of the forearm or of this last forwards, had occurred as the result of acute inflammation. The only luxation, the result of acute arthritis in the region of the wrist, which has been noticed hitherto, has been that of the ulna backwards.\nThis luxation is not an uncommon result of an attack of acute arthritis of the wrist, by which the ligament which connects the ulna to the cuneiform bone becomes softened and lengthened, and permits of the ulna being dislocated partially or completely backwards. Bonnet has commented on the frequency of this backward displacement of the ulna, and looks upon it as the smultaneous effect of the facility with which the ligamentous ties of this bone become softened and elongated, and of the faulty position in which the hand is kept by the patient, who remains usually in bed during these acute attacks, and preserves the forearm and hand in a state of complete pronation,\u2014a position which favours the displacement of the ulna backwards.\nWe have stated that acute arthritis of the wrist and carpal joints may be the result of inflammatory action, propagated from a wounded tendon of one of the fingers. The following is one of a few of those cases which had been admitted into the Richmond Hospital within a short period.\nCase. \u2014 John Murphy, a labourer, \u00e6t. thirty-eight, while engaged in a fight with another labourer, received from him a bite in the little finger. The inflammation which followed involved the tendons and their sheaths, and spreading up the forearm, implicated in its passage the carpal and meta-carpal joints as well as the wrist and radio-ulnar articulation, all of which became ultimately disorganised. The amputation of the forearm, below\nthe elbow-joint, became necessary. On making an anatomical examination it was found that there was complete disorganisation of the wrist-joint. All the bones of the carpus were loose and bathed in purulent matter.\nChronic Strumous Arthritis of the Wrist, or White Swelling. \u2014 This is a disease which is generally considered to have its origin in the cancellous structure of the bones. It is familiarly designated by many English writers by the well-known but somewhat equivocal name of \u201c white swelling.\u201d\nWhen we take into consideration that the bones and the joints which compose the region of the wrist are very superficially placed, and that they are frequently subjected to sprains and concussions from falls on the palm of the hand, we need not be surprised to find that these numerous injuries become so many determining causes, giving rise to a chronic inflammation of the bones and articular textures of the wrist, which frequently assumes the strumous character.\nAs to the symptoms of this disease, we have to observe that the patient complains of pain, sometimes in one point of the wrist, sometimes in another, which is increased on the slightest motion. Soon a swelling appears on the dorsum of the carpus, and the hand, from day to day, becomes more flexed on the forearm. After a time the region of the wrist assumes a globular form. The forearm, when compared with that of the opposite side, has an emaciated and wasted appearance. The patient usually has the hand supported on its palm, in the prone position, on some flat surface; the whole hand has a most helpless aspect; the fingers are swollen at their bases, and seem elongated and tapering towards their extremities : they are straight and motionless, and it is always with difficulty and pain that the patient moves them, \u2014 a circumstance we can easily account for, by recollecting that the inflammatory irritation which affects the wrist-joint is readily propagated to the tendons of the fingers which pass so immediately in front of it.\nThe synovial membrane in these cases is early distended by an increased secretion into the interior of the sac, and a fluctuating swelling may be occasionally perceived posteriorly, as in the case of acute arthritis ; but in the case of white swelling, instead of true fluctuation, there is in general nothing but a deceptive feeling of it, from the infiltration of the tissues in the region of the wrist, by a glairy gelatiniform structure, similar to that which constitutes the chief bulk of white swellings in general.\nDuring the second period of the disease, the degree of flexion of the hand and of the wi'ist-joint becomes increased, and the lower extremity of the bones of the forearm, particularly of the ulna, becomes very salient posteriorly. As the disease goes on, the bones of the carpus become more deeply carious ; chronic symptomatic abscesses form, and their contents make their way to the surface, which is frequently studded over, in advanced cases,","page":1524},{"file":"p1525.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\t1525\nwith the fistulous orifices of canals, which conduct purulent matter from the centres of some of the carious bones, and from the interstices between them. At this period of the disease we can, by holding the lower part of the forearm with one hand, and grasping the metacarpus with the other, move these parts laterally in opposite directions, clearly ascertaining that all the bones are loose and carious, and in an irrecoverable state of disorganisation. The constitution of the patient invariably sympathises deeply with this state of things ; and the wasting effects of hectic fever are found usuallj7 coinciding with the disease of the wrist and carpus ; and, if amputation be not performed, the life of the patient may be sacrificed. This operation, however, almost invariably succeeds in arresting altogether the hectical symptoms, and the patient is restored to health.\nThe scrofulous disease of the cancellous structure of the bones of the carpus, and of the carpal extremity of the radius, does not always proceed thus unfavourably. Occasionally, instead of suppuration, a resolution of the inflammatory action may ensue, or anchylosis, with partial displacement backwards of the bones of the forearm at the wrist-joint, may be established. This last, however, may be looked upon rather as an arrest of the morbid action than as a cure, because the patient is not only deprived of the use of the wrist, and sometimes of the medio-carpal joints, but also of the use of the fingers; inflammatory action in these cases having been communicated to the flexor tendons and their sheaths, rigidity of the ligaments, or even anchylosis of the joints of the fingers, too generally follows as a natural consequence.\nIt may here be asked, whether, in the progress of this disease, the wrist-joint is liable to those spontaneous displacements of the bones which other articulations affected with white swelling seem to be. To which we reply, If we except the partial displacement backwards of the ulna, previously mentioned, these displacements must be considered as rare. Bonnet of Lyons, who has had much experience, says he has not himself met with any case of spontaneous luxation of the hand, whether backwards or forwards, the result of disease ; nor has he read of any such recorded. Nelaton relates, however, that Richet showed him a preparation found in the dead-room, in which it was observed that the bones of the carpus had lost their usual relation to the radius, the inferior extremity of which was carried into the palm of the hand, while the bones of the carpus were carried backwards on the dorsal surface of the forearm. Numerous fistulous orifices were seen, which evidently had, up to the period of the patient\u2019s death, furnished a purulent discharge, so that the disease had not been completely cured, although it was manifest that the ligaments had resumed their firmness and solidity, and that the luxation had taken place a long time previous to death.\nHere, then, is a reply in the affirmative to\nthe quaere, whether spontaneous dislocation of the wrist-joint occur ; and an unquestionable example of dislocation of the bones of the forearm forwards adduced, on the respectable authorities of Nelaton and Richet. To this observation we may add the following, showing that complete dislocation backwards of both the bones of the forearm may occur at the wrist (seefig. 936.) ; and here the testimony as to this fact rests also on the production of a specimen found in the dissecting room*; its history is unknown. By examining. 936.\ning this preparation, in which the dislocation backwards of both the bones of the forearm had evidently taken place, we can observe much overlapping of these bones on the dorsum of the carpus, so that the styloid process of the dislocated radius quite overhangs the trapezium, even so far as the root of the meta-carpal bone of the thumb, and the ulna lies in contact with the back of the cuneiform bone, so that the articular extremity of the radius has passed down for more than an inch below its ordinary situation ; the anterior surface of the bones of the forearm, when they lie on the dorsum of the carpal bones, are solidly united to them. (See fig. 936.)\nAnatomical Characters of Chronic Strumous\n* This specimen formerly belonged to the Museum in Park Street, Dublin, where I saw it. It now is to be found, I presume, in the Museum of the Queen\u2019s College, Belfast.\n5 E 3","page":1525},{"file":"p1526.txt","language":"en","ocr_en":"1526\tWRIST-JOINT (Abnormal Anatomy).\nArthritis, or White Swelling, of the Wrist. \u2014 When we remove the integuments from the wrist, in one of those advanced cases of chronic strumous disease of the radio-carpal and inter-carpal articulations, we encounter the usual appearance of a gelatiniform effusion, of a yellowish-green colour ; we observe the tendons and nerves somewhat swelled, as if infiltrated; the ligaments all softened ; purulent matter occupying the interstices of the articular surfaces ; the bones easily yielding to pressure, hollow and carious in the centre of their cancillated tissue ; and leading from these carious bones, are seen fistulous canals opening extensively by numerous orifices on the cutaneous surface of the wrist.\nIn the Museum of the College of Surgeons of Dublin we find a preparation, which is truly designated as an instructive one, showing the effects of scrofulous disease on the bones and other structures of the wrist. To save the patient\u2019s life, it became necessary to perform an amputation of the forearm. The hand has been preserved in spirits, and the back of the carpus has been laid open to view. The wrist is semi-flexed ; the palrn and fingers are swollen, and the front of the joint is studded with fistulous orifices. One solitary fistulous orifice appears in the centre of the palm. The bones of the carpus, deprived of their synovial membranes and ligaments, are loose and disjointed ; and to use the words of the donor, the late Professor Todd, \u201c they felt during life like a bag of marbles.\u201d\nThere is also another preparation, styled \u201c scrofulous disease of the carpus, meta-carpus, and extremity of the radius,\u201d presented by Professor Porter. The bones are re-remarkably soft, light, and porous. The natural shape of each is considerably altered, by loss of substance in some parts, and deposits of new osseous matter in others : the latter, wherever it exists, has a peculiar spi-culated appearance; some of the bones are increased in size, others diminished ; the cartilages have, for the most part, disappeared ; the synovial membrane of the smaller joints had been completely destroyed ; that of the radio-carpal articulation was hypertrophied, soft, and pulpy. The ligaments were not recognizable, and the bones lay almost loose in a quantity of purulent matter, with which a fistulous orifice, in the front of the joint, communicated. The skin, the cellular tissue, and the sheaths of the tendons were infiltrated with a thin gelatinous fluid ; the median and ulnar nerves were remarkably enlarged.\nThe scrofulous disease, commencing in the centre of the cancellous structure of the bones of the carpus and carpal extremity of the radius, does not always proceed thus unfavourably. Anchylosis, with partial displacement of the forearm at the wrist-joint, may, as already stated, be established, as the result of the morbid action we are here treating of.\nIn the Museum of Anatomy in Leyden there is a preparation of the bones of the wrist, in which the carpal extremity of the\nradius and ulna are much enlarged and remarkably scabrous on their surface ; the radius and ulna are anchylosed firmly with each other near to the carpus ; the os lunare was united to both radius and ulna ; the os scapho\u00efdes, cuneiform and magnum, had totally disappeared; the trapezium was also firmly united to the meta-carpal bone of the thumb and with that of the index finger.\nIn the above-mentioned Museum at Leyden there is also another preparation, exhibiting anchylosis of the bones of the forearm, and of the carpus, at the wrist-joint, after the disease, which had arisen, we are told, from a scrofulous cause, had happily been cured.\nIn concluding, then, the account of the anatomical characters of the scrofulous caries of the bones which compose the region of the wrist, we may observe, that, as a result of this disease, some of the carpal bones are diminished in size in many cases, while in others they are enlarged. We have noticed some specimens in which two or three of the carpal bones have disappeared altogether, while others have had additional bony growths attached to them. The lower extremities of the bones of the forearm, in almost all the cases, were found rough and scabrous, and increased in bulk, particularly close to the wrist-joint. We, also, after our own examination of the bones of the region of the wrist, have to make the same observation that Sandiford has made relative to the specimens he has preserved in the Anatomical Museum of Leyden, of which he says, \u2014 \u201c Omnia hoec ossa levissima sunt.\u201d*\nChronic Rheumatic Arthritis of the Wrist. \u2014 The wrist-joints, together with the joints of the carpus, are very frequently affected with the disease we have elsewhere, in this work, called \u201c Chronic Rheumatic Arthritis,\u201d or rheumatic gout.\nWhen the joints which enter into the region of the wrist are engaged, the fingers are all more or less distorted, and their joints enlarged, as already described. (See Hand.)\nFemales are more liable to have their wrist-joints affected with chronic rheumatic arthritis than males, and elderly persons more commonly than those who are young ; but this disease is to be seen, occasionally, in young persons of both sexes. The disease, when it appears in the wrist-joint, will, in general, be found to affect, symmetrically, the right and left wrist of the patient. The cause of the disease is generally referred to rheumatic fever, and the other articulations of the patient are usually more or less implicated. The patient complains of pain in the joints, particularly at night, of stiffness and rigidity, and of a crackling sensation in them when they are moved. When we come to examine the wrist, it is remarked to present a preternatural convexity on its dorsal aspect, arising from an inordinate quantity of fluid poured out into the synovial sac of the joint. The\n* Museum Anatomicum, Sandiford, p. 244. vol. iii.","page":1526},{"file":"p1527.txt","language":"en","ocr_en":"WRIST-JOINT (Abnormal Anatomy).\nbursae of the extensor tendons, as they pass over the carpus, also become distended : these softer fluctuating swellings after a time subside, and the lower extremity of the radius and ulna, where they enter into the formation of the wrist-joint, enlarge ; longitudinal ridges of bone can be felt on the back of the radius close to the wrist-joint. The ulna, besides being much hypertrophied at its lowest point, rises abnormally above the level of the dorsum of the carpus. When the disease has been of long duration, the region of the wrist becomes contracted, the back of the carpus and hand presents an attenuated appearance, showing the course of the tendons, and allowing the ridges and prominences of the bone to become visible.\nAnatomical Characters. \u2014 When we remove the fibrous covering of the tendons which pass by the back part of the wrist-joint and carpus, we find that these tendons are generally deeply imbedded in bony sulci, or grooves. The capsular ligament and other fibrous structures, both on the palmar and dorsal aspect of the joint, seem to be denser and stronger than natural.\nOn examining the interior of the wrist-joint, we notice that all the articular cartilages of encrustation have been removed from the ends both of the radius and ulna, and that the inter-articular fibro-cartilage, which intervenes between the lower extremity of the ulna and cuneiform bone of the carpus, is removed. In general, at the usual period we are afforded opportunities for making our anatomical examinations, we find but little left of the synovial membrane by which we can judge; but in some cases we have found red synovial fimbri\u00e6 exist in the wrist-joint, just as we have noticed this same vascular condition of the synovial tissues to co-exist with the other anatomical characters of the chronic rheumatic arthritis, as they have shown themselves in other articulations which had been affected with this peculiar disease.\nRadius. \u2014 The lower extremity of the radius is usually somewhat enlarged, and the surface of the bone is scabi\u2019ous from small exostotic growth. We find the grooves on the back of the radius for the passage of the extensor tendons are preternaturally deepened.\nThe articular surface of the lower extremity of the radius, where formed for the reception of the summit of the carpus, is usually much hollowed out, and polished from porcellanoid deposition. The outline of the carpal surface of the altered radius is usually studded round with bony granules, or vegetations. When we look to the ulnar side of the lower extremity of the radius, we find the lesser synovial cavity for the reception of the carpal end of the ulna much enlarged, particularly in its antero-posterior diameter. This scaphoid cavity we find also presenting an eburnated surface, and on it fine parallel ridges and grooves are distinctly seen to run in the direction of the rotation of the ulna on the radius in pronation and supination. Where the lower extremity of the ulna con-\n1527\nfronts the cuneiform bone (the inter-articular fibro-cartilage having been removed), it presents a smooth and polished surface.\nUlna. \u2014 The carpal extremity of the ulna is frequently much enlarged, and furnished with exuberant bony growths ; its lowest extremity, where it confronts the cuneiform bone of the carpus (without the intervention of cartilage), is smooth. The part of the extremity destined for rotation on the radius is convex, and oval from before backwards, and of a form, of course, adapted to that of the little scaphoid cavity in the latter, and which is deprived of cartilage, eburnated, and similarly marked with corresponding parallel ridges and grooves.\nCarpus. \u2014 In our anatomical investigations into the state of the hands of those who have long laboured under chronic rheumatic arthritis, we have found the bones of the carpus to be much altered by this disease : in general, the region which these bones constitute will be found to have all its dimensions contracted within a smaller compass then natural. The form of each individual bone is so much changed, that, if found detached, it could scarcely be recognised as a carpal bone. The cartilaginous structure naturally intervening between all the bones is always absorbed.\nCruveilhier has said that, in the anatomical examination of one of his cases of this disease, he found the bones of the carpus confounded together into an irregular mass, so that it was difficult to say the part which each took in the construction of the carpal region.\nOn examining, anatomically, the bones of the region of the wrist of a patient who had been ten years labouring under this disease, and was under our own immediate observation for almost the whole of this period, we found the bones of the carpus were exceedingly rough on their non-articular surfaces ; each individual bone was found much altered from its normal figure ; some were enlarged beyond their usual size, others diminished : the true annular ligament of the carpus, which connected the small bones together on their palmar aspect, and contributed to maintain the arched form of this region, was much shorter than usual.\nWhen we examined each bone, we found that the scaphoid was eburnated on its superior articular surface, where it corresponded to a similar surface on the carpal end of the radius. Below, the scaphoid, instead of contributing, with the head of the os magnum, to form part of the medio-carpal articulation, was really united to the head of the os magnum by true bony anchylosis. The semilunar and cuneiform of the first range were much enlarged. The os lunare, where, by its lower concave surface, it corresponded to half of the head of the magnum, was not, like the scaphoid, united to this last bone, but, on the contrary, both surfaces of the magnum\n* Vide a work on Chronic Rheumatic Arthritis, by the author, shortly to be published.\n5 E 4","page":1527},{"file":"p1528.txt","language":"en","ocr_en":"1528\tWRIST-JOINT (Abnormal Anatomy).\nand lunar bones, which confronted each other, were covered with an ivory-like polish. The trapezium, where it supported the first phalanx of the thumb, was polished on its pulley-like articular surface. The trapezoides was much diminished in size, and solidly anchylosed with the first phalanx of the index finger. The transverse diameter of the magnum was not one quarter of an inch ; and the loss of breadth to this degree accounted somewhat for the abnormal narrowing of the carpus already noticed. The cuneiform was normal, as well as the pisiform. The junction, then, of the magnum with the scaphoid, and the equally solid bony union of the trapezoides with the meta-carpal bone of the index finger, were the only articulations of this region, or, indeed, of the whole skeleton of this individual, which presented specimens of true bony anchylosis. The cause of the eburnation of the surfaces of some of the carpal bones might have been that these bones bore occasionally much of the weight of the man in progression, because he had been much disabled in his lower limbs, and habitually used crutches.\nSynovial Tumours of the Region of the Wrist \u2014 Synovial tumours generally present themselves around the joints of the extremities ; and the wrist seems especially liable to them. By the term synovial tumours of the wrist, wre do not mean those formed by an increased effusion into the proper synovial sac of the radio-carpal articulation, but enlargements constituted by bursae in this region.\nSynovial cysts, called ganglions, are frequently seen on the back of the wrist and carpus. They are of a globular form, and, as to size, vary from that of a hazel-nut to that of a walnut. They are usually situated at the level of the medio-carpal articulation in the course of the extensor tendons as they pass to the carpus. These tumours are slightly moveable, indolent, and painless, without any alteration in the colour of the skin which covers them from that which is natural. The contents of these little swellings are found to be synovia of a variable consistency : sometimes it is serous and limpid ; occasionally the contents are constituted by a thick transparent jelly. The cyst seems to be formed by the reticular tissue which immediately covers the sheath of the extensor tendons. The part of the cyst which corresponds to the skin is united to it by a layer of very thin cellular tissue, but loose enough to allow of the skin being easily raised up. The part, on the contrary, which is deeply situated reposes in the sheath of the tendons, or the capsular ligament of the wrist, and is firmly connected to them. This union is sometimes so intimate that it is impossible to take away the cyst without interfering with the tendon or the articular capsule.\nThe thickness of this cyst varies much. Sometimes it is thin and translucent, and it breaks when subjected to but little pressure; at other times its thickness and its texture are such that the most violent efforts cannot rupture it.\t.\t.\t.\nWe have usually seen this disease in fe-\nmales more than in males ; and the cause of the origin of these little tumours in the wrists of the former appeared to us frequently attributable to over-exertion, such as prolonged playing on some musical instruments, such, for example, as the harp or piano.\nWhatever may have been the cause for the origin of these encysted tumours, once formed, they for a time increase in a gradual manner ; and when they have attained a moderate size, they cease to grow. They sometimes, though rarely, subside spontaneously.\nThe interior of the membranous sac, in the distention of which, by a glairy fluid, the tumour consists, is smooth and polished. The interior of these cysts generally have no communication whatever either with the medio-carpal or wrist-joint itself ; but Velpeau says he has seen two cases in which he could easily press the liquid contained in the cyst into the articulation of the wrist if he at the same time gave certain movements to the joint. He adds, that twice he had an opportunity, in the dead body, to show that these cysts communicated with the interior of the joint.\nMorbid Condition of the Synovial Rursce of the Flexor Tendons.\u2014The swellings which these enlarged bursae constitute, do not present the same regularity of form that ganglions do.\nThe cause of their origin may generally be referred to some great exertion \u2014 to a fall or other external violence. I have known, in one case, one of these swellings appear without having been produced by any injury. The constitution of this patient was very decidedly of the rheumatic character.\nThe species of swelling we are now referring to commences in the synovial bursa which envelopes the flexor tendons of the fingers as they pass beneath the anterior annular ligament of the wrist : the swelling consists of an increased quantity of synovial fluid effused into the cavity of the little sac the bursa constitutes. At first the effusion is small, and the bursa keeps within its normal boundary, behind the anterior annular liga ment ; but the accumulation of synovia increases by degrees ; and then the swelling appears divided into two parts, which are separated from each other by the annular ligament, which seems to form a transverse band which constricts the sac, leaving a tumour above the annular ligament in front of the wrist, and another beneath the level of this ligament in the palm. Pressure on the portion of the sac above makes the synovial fluid pass down into the part of the bursal sac beneath. In these cases the skin preserves its colour and normal mobility, the fingers become somewhat flexed, and there is some difficulty experienced in fully extending them. The patient suffers no pain, but only complains of a numbness and weakness in the fingers, hand, and wrist.\nOn compressing one of the extremities of this tumour (as, for example, that placed\n*\nDictionnaire de M\u00e9decine, tom. 25, pi. 294.","page":1528},{"file":"p1529.txt","language":"en","ocr_en":"1\u00d629\nWRIST-JOINT (Abnormal Anatomy).\nabove the annular ligament), while the fingers of the opposite hand are placed on the other extremity, which is placed beneath this fibrous band, we readily perceive a \u201cfrottement \u201d which is quite peculiar. This \u201c frottement \u201d is caused by the passage to and fro, under the true annular ligament of the wrist, of small foreign bodies which are not unlike barley grains or those of boiled rice. Their forms are exceedingly variable. They are usually of a white colour, and have a polished surface. They are found in vast numbers in the same cyst, mixed with a more or less considerable quantity of glairy synovial liquid. They are ordinarily free from all adhesions to the parietes of the bursa.\nMany theories have been formed as to the origin of these little bodies found loose in the bursa, about the wrist, and elsewhere.\nDupuytren thought he had established the theory that they were hydatids. Laennec and Raspail agreed with him in this view ; but Bose, to whom Dupuytren referred, dissented. The last-mentioned naturalist looked upon them as concretions of lymph of an adipo-cerous nature. He says, \u201c They are not to be considered as \u2018 hydatids,\u2019 because they have not given any sign of life on escaping from the cyst.\u201d On dividing these bodies, he found them uniform throughout, whilst that of hydatids are always hollow ; and again, because submitted to a strong lens, they have appeared to him to be nothing else than an inorganic mass, whether he examined them when recent or dried.\u201d\nSir Benjamin Brodie\u2019s opinion now seems generally to prevail. It is adopted by Nelaton * and other French physiologists : \u2014 \u201c There seems to be no doubt but that these loose bodies have their origin in the coagulated lymph which was effused in the early stages of the disease ; and I had opportunities, by the examination of several cases, to trace the steps of their gradual formation. At first the coagulated lymph forms irregular masses of no determined shape, which afterwards, by the motion and pressure of the contiguous parts, are broken down into small portions. These by degrees become of a regular form, and assume a firmer consistence, and at last are converted into the oval bodies above alluded to.\u201d j*\nExamples of these have been seen in the synovial sheaths of the radial extensors as well as on the back of the wrist in the course of the extensors of the fingers. But it is, nevertheless, certain that the bursa of the flexor tendons, situated in front of the wrist and carpus, and behind the true annular ligament of this region, is the special locality in which these foreign bodies are most frequently found.\nPainful Crepitation of Tendons around the Wrist. \u2014We notice, sometimes, around the carpus and in the inferior extremity of the\n* En 1819 M. Brodie donna une interpretation satisfaisante de leur \u00e9tiologie en les rattachant aux epanchemens sero-albumeux. (Nelaton, Pathologie Chirurgicale.')\nf Brodie on the Diseases of the Joints.\nforearm, a swelling which is peculiar in this, that, whenever the tendons around which the swelling forms are moved, there is thereby elicited a very peculiar crepitation.\nThis crepitation is noticed along the course of the extensor carpi radialis longior and brevior, and in that of the long abductor and short extensor of the thumb. This swelling is not globular, nor is it so well defined as a ganglion, but may be said to represent in its form a portion of a spiral which, parting from the dorsal surface of the forearm, soon turns round the external part of the radius to gain the root of the first metacarpal bone.\nThis swelling seems to be of an inflammatory nature, and is occasionally accompanied with a superficial redness of the skin ; and pressure on this part becomes painful to the patient. If the surgeon places his thumb or fingers on the postero-external surface of the forearm, near to the wrist-joint, where the oblong swelling exists, and at the same time desires the patient to move the hand by flexing and extending the wrist-joint, or exert the muscles, the peculiar crepitation which characterises this lesion is soon perceived.\nIt is not very easy to convey an idea of this crepitation ; but it has been compared by many to that produced by the crushing together, with our fingers, portions of finely powdered starch, or to the effect which we feel produced when we walk over snow. When once recognised, it is perceived to be quite different from that crepitation which is produced by the movement on each other of the fragments of broken bones or the rubbing together of roughened articular surfaces. This disease has for its anatomical seat the fibro-synovial sheaths of the tendons already mentioned. These extensor tendons, namely, the two extensor radialis longior and brevior, as well as those of the long abductor and short extensor of the thumb, cross each other, each in special sheaths or canals formed on the back part and external edge of the lower extremity of the radius ; and if inflammation attack the lining membrane of these fibro-synovial sheaths, it is plain that, in this anatomical arrangement, there may be seen many circumstances to favour the development of this crepitation.\nThis affection has not, we believe, ever been observed to have come on spontaneously, but generally to have arisen from some violent and continued efforts of the wrist and hand.\nIt has been noticed in soldiers and masons, and in those who are in the habit of twisting the forearm, as in the act of forced pronation of the forearm of washerwomen in wringing clothes. The tumefaction, the swelling, pain and heat, and the crepitation also, once commenced, augment generally for four, six, or eight days ; and if the patient be guilty of any imprudence, the evil is maintained to the same degree even to the twelfth or fourteenth day, after which it ordinarily terminates in resolution.\n(Robert Adams.)","page":1529},{"file":"p1530.txt","language":"en","ocr_en":"Addendum to the Article Urethra.\nIn justice to a distinguished anatomist and surgeon, Mr. Henry Hancock, whose claims to priority of the discovery of unstriped muscular fibres in the urethra were overlooked by the author of the article Urethra, the Editor thinks it right, with the assent of the author of that article, to insert the following paragraph, drawn up by Mr. Hancock, as an addendum to it : \u2014\nThe urethra itself is a membranous tube, consisting of mucous membrane, presenting villi on its free surface for the most part arranged in rows, some being conical, others tuberculated, covered by epithelial scales. The outer surface of the urethra is closely invested by cellular tissue, external to which is found a layer of organic muscular fibres, similar to, and in fact continuous with, the muscular coat of the bladder. This last-named structure consists of two layers, an internal and an external ; the external passes forwards on the outside of the prostate gland ; the internal, on the contrary, accompanies the mucous lining of the bladder, when it becomes urethral through the prostate gland, forming a covering of involuntary muscular fibre to the canal in its passage through the gland. In front of the prostate, the two layers of muscular fibre unite and invest the membranous portion of the urethra, where they may easily be distinguished from the voluntary muscles of the part. Reaching the bulb they again separate into an internal and an external layer ; the internal continues forwards to the orifice of the urethra, lying between that canal and the corpus spongiosum ; the external passes on the outer surface of the corpus spongiosum, separating\nit from its fibrous investment, to which the fibres adhere pretty closely. These latter, like the internal, are continued forward to the orifice of the urethra, and in their course they invest the spongy portion of the bulb, the urethra, and the glans penis, entering very largely into the formation of the peculiar structure found at the orifice of the urethra, and which appears to consist almost entirely of involuntary muscle and cellular tissue. Hence, the corpus spongiosum urethras lies between two layers of involuntary muscle, the one separating it from the urethra, the other from its fibrous investment; and this arrangement obtains wherever the corpus spongiosum exists, whether the quantity thereof be small or great. On the under and lateral portion of the urethra, where the quantity is abundant, the corpus spongiosum lies between two layers of involuntary muscular fibre. On the upper surface of the urethra, where the quantity is comparatively small, the same arrangement may be observed, whilst at the glans, which is not formed merely by increased development of the spongy tissue, but also by a folding back, as it were, of the spongy tissue over the corpora cavernosa, we find these muscular layers multiplied.","page":1530},{"file":"p1531.txt","language":"en","ocr_en":"ANALYTICAL INDEX\nTO THE\nFOURTH VOLUME.\nPLEURA, 1.\nmediastinum, 1. ligamentum latum pulmonis, 2. pleura pulmonalis, 2, pleura costalis, 2. pleura diaphragmatica, 2.\nPolygastria, class of microscopic animalcules, 2. their division into families by Ehrenberg, 3. locomotion of animalcules, 5. nutritive system, 14. dental system, 15. muscular system, 15. nervous system and organs of sense, 16. secretions, 16. reproduction, 16. fissiparous generation, 16. gemmiparous reproduction, 17. sporiferous reproduction, 17.\nPolypifera, class of zoophytes, 18. division into families, 19. hydras described, 20.\nextensors of the tentacula, 22. alcyon id\u00e6 described, 24.\nnutrition of the alcyonid\u00e6, 27. corallid\u00e6 or cortical polypes, 30. corallium rubrum, 31. isis hippuris, 32.\nmadreporidas, madrephyllidas, 33.\ntheir fungias, 33. pennatulid\u00e6, 38. actiniad\u00e6, 38. aulozoa : tubularidas, 40. tentacular apparatus, 41. digestive system, 41. circulation, 42. reproduction, 42. mode of propagation, 42. sertularidas, 48. bryozoa, 50.\nmuscular system, 52. alimentary system, 54. reproduction, 55.\nPopliteal Region, and Popliteal Artery, 60. varieties, 63.\nbranches of the popliteal artery, 64. operative relations, 64.\nPorifera, or sponges, 64.\ndivision into families by Blainville, 65. skeleton, 66. gelatinous cortex, 67. irritability, 67-circulation of water, 67 \u2022 reproduction, 69.\nProducts, Adventitious, 71.\n[The term applied to the substances which, either produced by or developed in connexion with the animal frame, neither form a natural constituent element, nor a natural secretive product, of the structure amid which it is evolved.]\ncalculi : urinary calculi, 74. uric acid calculus, 77. urate of ammonia calculus, 78. oxalate of lime calculus, 78. cystin or cystic oxide calculus, 79. phosphate of ammonia and magnesia calculus, 80.\nneutral phosphate of lime calculus, 80. mixed phosphates, 80.\nneutral phosphate of ammonia and magnesia, 80. xanthic oxide calculus, 80. carbonate of lime calculus, 80.\nProducts, Adventitious (continued1. carbonate of magnesia, 81. urate of magnesia, 81. urates of soda, potassa, and lime, 81. phosphate of magnesia, 81. chloride of sodium, 81. renal calculi, 81. calculi of the prostate gland, 82. pr\u00e6putial calculi, 82. lachrymal calculi, 82. nasal calculi, 82. calculi of frontal sinus, 82. calculi of mouth, 32. salivary calculi, 83. the tonsils, 83. pharynx and oesophagus, 83. gastro-intestinal calculi, 83. biliary calculi, 85. pancreatic calculi, 86. seminal calculi, 86. mammary calculi, 86. vaginal and pudendal, 86. uterine, 86. pseudo-calculi, 86. elementary cell, 86. f\u0153tal, 87. placental, 87.\nvascular ; arteries, parietal, 87. veins, parietal, 89. central, 89.\nlymphatic and lacteal, 89.\nserous and synovial cavities, 90.\nfibrous membranes, 90.\ncerebral, 90.\nuterine, 90.\nfallopian tubes, 90.\npulmonary concretions, 90.\narthritic, 90.\ncutaneous, 91.\nein compounds, 91.\nalbumen, 91.\nfibrin, 93.\ncasein, 94.\nglobulin, 94.\nfat ; fatty substances, 94. in the liver, 94.\npancreas, 95. mamma, 95. kidney, 95. testicle, 96. lungs, 96. arteries, 96. muscles, 96. tendon, 96. nerves, 96. bones, 96.\nadventitious products, 97. fatty matters excreted in the semi-fluid state, 97. in the urine, 97. f\u00e6ces, 97. saliva, 97. sweat, 97. encysted fats, 97. cholesteric fats, 98. tumours, 98. granules, 98. patches, 98. scales, 98. sugar, 99.\nsaccharine diabetes, 99.\nfluid","page":1531},{"file":"p1532.txt","language":"en","ocr_en":"1532\nANALYTICAL INDEX.\nProducts, Adventitious (continued). blastemal formations, 100.\ntheir potential qualities, 102. deposits : typhous deposit, 103. tuberculous deposit, 104. purulent deposit or pus, 110. mucus, li4. softened fibrin, 114. epithelial fluid, 115. melanic deposit, 116. stagnation, 117. extravasated blood, 117. chemical action, 117.\nintroduction of black coloured substances from without, 117. diphtheritic deposit, 118.\nwhite thrush, 118. growths, cells, 118. granules, 119. nuclei, 119. fibrils, 119.\nenlargement of growths, 120. their decay, 121. their removal, 121. cicatrisation, 121. vital effects, 122. localisation. 122.\ninoculability, 124. h\u00e6matoma, 125. sarcoma, 126. cystoma, 127. angeiectoma, 127. melanoma,'128. of fat basis ; lipoma, 129. steatoma, 130.\ncholesteatoma. See Cholesteric Fats, p. 98. of gelatin basis ; fibroma, 130. enchondroma, 132. osteoma, 134.\nin unnatural sites, 134. in the natural tissues, 134. undetermined basis : colloma, 135. infiltrating growths : cancer, 136. pseudo tissues, 138. induration matter, 138. simulating the natural tissues, 139. extra-vascular tissues, 139.\nnail. See Tooth, 142. cartilage, 139.\nsimple vascular tissues : cellular tissue, 140. serous tissue, 140.\nfibrous and elastic pseudo-tissues, 141. osseous pseudo-tissue, 141. nervous pseudo-tissue, 141. blood-vessel, 141. erectile tissue, 142. lymph vessel, 142. fibrous and spongy cartilage, 142. hair, 142. tooth, 142. cutaneous, 143. mucous, 143. glandular, 143 muscle, 143. unstriped fibres, 143. germ formations ; parasites, 143. liquid adventitious products, 144-gaseous adventitious products, 145.\nProstate Gland, 146.\nform, position, and adjacent viscera, 146. levator prostatas, 147.\nligamenta pubo-prostatica media et lateralia, 147.\nuvula vesic\u00e6, 149.\nintimate structure, 149.\nliquor prostaticus, 150\u00bb\nsinus pocularis, 151.\nuterus cystoides, 151.\ndevelopment of the prostate and vesic\u00fcla pros-tatica, 153.\nfunction of the prostate gland, 153. morbid anatomy, 154. hypertrophy, 154. atrophy, 156. inflammation, 156. abscess, 156. ulceration, 156. tubercles, 157. cancer, 157. fibrous tumours, 157. cystic prostate, 157. prostatic concretions, 158. prostatic calculi, 159.\ndescribed by Vogel, and analysis by Las-saigne, 159.\ncomparative anatomy, 160.\nprostate in mammalia, 160. in the ape, 160. in the tarsier, 163. in the galeopitheci, 160. in the roussette, 160. in the dormouse, 160. in the hedgehog, 160. in the mole, 160.\nProstate Gland (continued).\nin the hear, 160.\nin the otter, weasel, and marten, 170.\nin the ichneumon, 160.\nin the dog and cat, 160.\nin the hyena, 160.\nin the marmot, 160.\nin the rabbit, 160.\nin the squirrel, 160.\nin the rat, 160.\nin the agouti, 161.\nin the guinea-pig, 161.\nin the elephant, 161.\nin the wild boar, 161.\nin solipedes, 161.\nin ruminants, 161.\nin the stag, axis, and buffalo, 161.\nin the chamois, 161.\nin the seal, 161.\nin the cetacea, 161.\nin the marsupial sub-class, as the kangaroo, 161.\nin the opossum, 161. in the wombat (doubtful) 161. among amphibious reptiles are found glands analogous to the prostate, 161.\nProtein, the basis of the greater portion of the bodies of all animals, 162.\nanalysis of fibrin, albumen, and casein, 162. tritoxide of protein, 163. binoxide of protein,\u2018,163. \u2019 third oxide of protein, 163. protein and chlorine, 163. and nitric acid, 164. and sulphuric acid, 164. and hydrochloric acid, 164. and potash, 164. erythroprotid and protid, 164. fibrin, average proportions in animal products, 165. fibrin and sulphuric acid, 166. and nitric acid, 166. and acetic acid, 166. and hydrochloric acid, 166. and potash, 166.\nalbumen, proportion in animal products, 167. casein, proportion in the milk of animals, 168. vegetable fibrin, 169. vegetable albumen, 169. vegetable casein, 169.\nPteropoda, an order of mollusca, 170.\norganisation of this class of marine animals, 170. their habits described by M. d\u2019Orbigny, 171. integument of the clio, 171. muscular system, 172. locomotive apparatus, 173. respiration and circulation, 173. nervous system, 173. eyes, 174.\nhead-cowls and tentacula, 174. conical appendages to the head, 175. mouth of the clio, 176. generative system, 177. ovary, 178.\nPulse, 181.\nage, infancy, 182.\npulse at different periods of life, 182. sex, 183.\ntemperament, 185. stature, 185. posture, 185.\ncause of difference of pulse in different positions, exercise, 189.\ndiurnal variations of the pulse, 189. in rest, 191. in sleep, 191. food, 192.\nmental emotions, 192-\ntemperature of the body, 192.\ndensity of the air, 192.\nrelation of the pulse to the respiration, 192.\nQuadrumane, 194.\ntheir division into simi\u00e6 and lemurin\u00e6, 195.\nosteology : the.chimpanzee, orangoutan, siamang, mandrill, 187. myology, 205. neurology, 206. angeiology, 208. splanchnology, 208. second group of simi\u00e6 described, 210. lemurin\u00e6, or second family of quadrumana, 214. osteology, 216. myology, 218. neurology, 219.\nRadial and Ulnar Arteries, 221. radial artery, its relations, 222. in the forearm, 222. in the wrist, 222. in the palm, 223.\nbranches of the radial artery, 223. arteria radialis recurrens, 223. arteria superficialis vol\u00e6, 223. arteria anterior carpi radialis, 223.","page":1532},{"file":"p1533.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\t1533\nRadial and Ulnar Arteries (continued).\narteria dorsalis carpi radialis, 223. arteria dorsalis pollicis, 223. arteria magna seu princeps pollicis, 224. arteria radialis indicis, 224. ulnar artery, 224.\nits relations in the forearm, 224.\nin the hand, 224. branches of the ulnar artery, 225. arteria interossea, 225. arteri\u00e6 carpi ulnaris, 225. communicans ulnae, 226. digital arteries, 226.\nvarieties of the radial and ulnar arteries, 226. varieties of origin, 226. high origin of the radial, 226.\nvarities in its distribution, 226. high origin of the ulnar, 227. its course, 227. size, 227.\ndiseases and injuries of the radial and ulnar arteries,\n228.\naneurism, 228. false aneurism, 228.\nRadio-ulnar Articulations, 228.\nupper radio-ulnar articulation, 228. round head of the radius, 228. sigmoid cavity of the ulna, 229. annular or orbicular ligament, 229. synovial membrane, 229. movement, 229.\nlower radio-ulnar articulation, 229. lower extremity of the radius, 229. lower end or head of the ulna, 229. triangular fibro cartilage, 230. synovial membrane, 230. movement, 230. pronation and supination, 230. dislocations of the joints, 231.\nRen*, or the Kidney, 231.\nrenal organs in the lower animals, 232. in insects, 232. in the arachnida, 232. in the lamellibranchiata, 232. in the gasteropoda, 232. among the cephalopoda, 232. in fishes, 232 in reptiles, 233. in birds, 233.\nkidneys of mammalia, 233. human kidney, 234. form, 234.\ndimensions and weight, 234. position and relations, 234. anterior surface, 234. posterior surface. 235. circumference, 235. extremities, 235. ureter or excretory duct, 235. its direction, 235. and relations, 235. blood-vessels of the kidney, 235. emulgent or renal arteries, 235. emulgent or renal vein, 236. lymphatics, 236. nerves, 236.\nstructure of the kidney, 236. cortical substance, 236. medullary substance, 237. capsule, 238.\ncalices, infundibula, and pelvis, 238. minute structure, 239.\nfibro-cellular matrix, 239.\ntabuli uriniferi, 241.\nmode of injecting the tubes, 241.\ncourse and termination of the tubes, 242.\nstructure of the tubes, 242.\nmalpighian bodies, 243.\ntwo distinct systems of capillary vessels in kidneys, 249.\nportal system of the kidney, 250. comparison between the hepatic and renal portal circulation, 251. epithelium of the kidney, 252. ciliary motion of the tubes, 253. epithelium of the pelvis and ureter, 254. function of the malpighian bodies and uriniferous tubes, 254.\npathology of the kidney, 256.\ndisease of the kidney from retention of urine, 256. disease of the kidney from renal calculi, 256. disease of the kidney from external violence, 257. extension of disease from other organs to the kidney, 257.\ndiseases resulting from a constitutional cause, 257.\nacute suppurative nephritis, 257.\nacute desquamative nephritis, 257.\nchronic desquamative nephritis, 258.\nrenal h\u00e6morrhage, 261.\nfatly degeneration of the kidney, 262.\n* See note to this article, page 231.\nRen, or the Kidney (continued).\nhydatids in the kidney, 263. cancer of the kidney, 263.\nReptilia, class of vertebrate animals, 264 division into families, 265. osteology of chelonian reptiles, 26S. plastrum or ventral cuirass, 266. pelvis, 267.\nbones of the carpus, 267. . feet, 268. tarsus, 270.\nosteology of ophidians, 272. myology of chelonian reptiles, 273..\nmuscles of the neck and head, 275. of the shoulder, 275. of the arm, 276. of the forearm, 278. of the hand, 279. of the thigh, 279. of the leg, 280.\nmyology of ophidian reptiles, 281. muscles of the spine, 281. of the ribs, 281. of the head, 282. anterior temporal, 282. middle temporal, 282. posterior temporal, 283. muscles of the head of the rattlesnake, 283. muscles of the throat, 284. myology of the salamander, 285. muscles of the head, 285.\nof the trunk, 285. of the extremities, 286. teeth of reptiles, 287. of the crocodile, 288. of the lizard, 288. of the boa constrictor, 289. poison fang of serpents, 290. poison apparatus of the viper, 291. tongue of reptiles, 292. digestive system, 294. stomach, 296. viscera, 297. lymphatic system, 300. lymphatic hearts, 302. venous system, 303. arterial system, 303. organs of respiration, 306. circulation of the blood, 307. the heart, 307. nervous system, 309. the brain, 309. sympathetic system, 312. organ of hearing, 313. organ of vision, 314. appendages to the eye, 314. lachrymal apparatus, 316. urinary apparatus, 316.\nthe kidneys, 316. male organs of generation, 317. female organs of generation, 321. the oviducts, 321. development of the embryo, 322. tegumentary system, 324. musk gland of the crocodile, 325. anal glands, 325.\nRespiration, 325.\nrespiration of plants, 328. respiration of animals, 329. respiratory membrane, 330. gills or branchi\u00e6, 331. trache\u00e6, 331. lungs, 331.\nin birds, 331.\nman : apparatus for renewing the air in the lungs of the human species, 333.\nfrequency of the respiratory muscular movements, 338.\nquantity of air drawn into, and expelled from, the lungs, 339.\nquickened or forced inspiration, 340. changes upon the atmospheric air in respiration, 342.\nanimal matters exhaled from the lungs, 344. quantity of carbonic acid gas in the expired air, 345.\nperiod of the day, 346. digestion, 346. fasting. 347. alcohol, 347.\nconditions of the mind, 348. exercise, 348. temperature, 348. effect of the seasons, 349. barometric pressure, 349. age, sex, and constitution, 350. influence of the respiratory movements upon the evolution of carbonic acid from the lungs, 351. frequency of the respiratory movements, 351. bulk of the air expelled, 352.\nstoppage of the respiratory movements for a time, 352.\nquantity of oxygen absorbed at the lungs, 354.","page":1533},{"file":"p1534.txt","language":"en","ocr_en":"1534\tANALYTICAL INDEX.\nRespiration (continued).\ndifferences between arterial and venous blood, 356. free gases in the blood, 358. theory of respiration, 361.\nintermixture of air in the upper and lower apparatus, 362. I\nactions between the blood and the atmospheric air,\n362.\ncauses of the change of colour in the blood, 365.\nRodentia, an Order of mammiferous vertebrata, 368. bones of the cranium, 369. in the hare, 369. in the rabbit, 370. in the marmot, 370. in the squirrel, 370. in the beaver, 370. in the cape mole, 370. in the ondatra and water voles, 370. in the rat and rat moles, 371.. in the gerbilles, 371. in the hamster, 371. in the dormouse, 371. in the rhyzomys, 371. in the jerboa, 371. in the helamys, 372. in the echimys, 372. in the capromys, 872. in the porcupine, 372. in the coendou, 372. in the paca, 372. in the guinea-pig, 372. in the couia, 373. in the agouti, 373. in the capybara, 373. in the viscache, 373. in the kerodons, 373. in the chinchilla, 373.\nbones of the face of various animals of this order, 374 to 379.1\nbones of the carpus, 379. clavicle, 380. \\ femur, 380. fibula, 381. teeth, 382.\norgans of digestion, 385. stomach, 386. intestinal canal, 389. liver, pancreas, spleen, 390. lympathic system, 390. arterial system, 390. venous system, 391. nervous system, 391. organs of the senses, 392. male organs of generation, 392. female organs of generation, 396.\nRotifera, or Rotatoria, class of invertebrate animals, 396. division into families by Ehrenberg, 400. tegumental system, 409. motory system, 411. digestive system, 411. the teeth, 412.\nvascular and respiratory systems, 413. nervous system and organs of the senses, 414. reproductive system, 414.\nRuminantia. See Supplement.\nSaliva, 415.\nquantity of saliva secreted during the day, 415. physical qualities, 415. specific gravity, 416. chemistry, 416. saliva of children, 417. male and female saliva, 417. general properties, 418. saliva of animals, 418. saliva in disease, 419. salivary calculi, 419. ranula, 420. hydrophobia, 420. infection, 420. syphilis, 420. mercurial salivation, 420. various kinds of diseased saliva analysed, 421. spontaneous saliva, 421. gelatinous saliva, 422. milky saliva, 422. urinary saliva, 422.\nSalivary Glands, 422.\nparotid gland, 423. submaxillary gland, 424. sublingual gland, 424. subsidiary salivary glands, 425. labial glands, 426. buccal glands, 426. molar glands, 426. palatine glands, 426. anterior lingual glands, 426. posterior lingual glands, 426. minute structure, 427. vascular supply, 428. nervous supply, 428. lymphatics, 428. saliva of mastication, 429. saliva of deglutition, 429.\nSalivary Glands {continued). morbid anatomy, 430. salivary fistul\u00e6, 431. nature of ranula, 431. comparative anatomy, 431.\nsalivary apparatus of entozoa, 431. among enchinodermata, 431. in myriapoda, 431. in the insecta, 431. in cirrhopoda, 432. among pteropoda, 432. in cephalopoda, 432. among reptiles, 432. in aves, 432. in mammalia, 433. in the ruminantia, 433. among edentata, 433. in carnivora, 433.\nScapular Region, 433. the muscles, 433.\nsupra-scapular nerve, 434. supra-scapular artery, 435. supra-spinal branch, 435. infra-spinal branch, 435. below the spine of the scapula, 435. deltoid muscle, 435.\ntrapezius and latissimus dorsi muscles, 435. infra-spinatus muscle, 436. teres minor muscle, 436. teres major, 436. triangular compartment, 436. quadrilateral compartment, 436. posterior scapular artery, 436. veins of the scapular region, 437. lymphatics of this region, 437. uses of the scapula, 437. furuncular inflammation, 438. chronic abscesses, 438. fractures, 438. ablation, 438.\nScrotum, 438.\nskin of the scrotum, 438. areolar tissue, 438. vessels of the scrotum, 439. nerves, 439.\nSecretion, 439.\nexcrementitious and recrementitious secretions, 439.\norgans of secretion, 441.\ndevelopment of cells, 441.\nexcretory organs of animals, 443.\nabsorbent system, 444.\nbiliary apparatus in various animals, 445.\nbiliary ducts in mammalia, 450.\nhepatic cells in various animals, 452.\nsources of the demand for secreting function, 455.\nexistence of the elements of secretions in the blood,\n459.\npresence of urea in the blood, 459.\npre-existence of uric acid in the blood, 460.\nhippuric acid detected in the blood by Dr. Garrod,\n460.\nkreatine and kreatinine, 460. metastasis of secretion, 461. secretion of milk, 463. menstrual flux, 463.\ninfluence of the nervous system on the secreting process, 464.\nmammary secretion influenced by the state of the mind, 464.\nquantity and quality of the milk changed by mental emotions, 465.\nremarkable instances produced by excitement, 465. phenomena produced over the secreting processes by mental states, 466.\t. .\nchanges in the state of nutrition arising from injured nerves, 468.\nSemen, 472.\nhistological elements of the semen, 472. periodical development of the spermatozoa and testicles, 473.\nform and history of development of the spermatozoa, 474.\nspermatozoa in man, 474. in mammalia, 475. in aves, 477. in reptilia, 480. in fishes, 483. in mollusca, 484. in insecta, 488. in Crustacea, 493.\nmorphology and development of the spermatozoa, 499. organisation of the spermatozoa, 502. motions of the spermatozoa, 502. chemical composition of the semen, 505. physiological office of the semen, 507.\nSensation ; perception of the mind, 508.\nsensation distinguished as common and special, 509. objective and subjective sensations, 510. reflex sensations, 510.\nSensibility, like sensation, involves the power of affecting the mind through the body, 510: the word also applied to nerves, to signify their power of evolving the nervous force, 511.","page":1534},{"file":"p1535.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\n1535\nSerous and Synovial Membranes, 511. white fibrous tissue, 512. yellow fibrous tissue, 512. areolar tissue, 513. 524. burs\u00e6, 513.\nsubcutaneous bursas, 514.\nthe internal surface covered by a cell-growth, 514. character of the cells, 515. arrangement of the cells, 515. subtendinous burs\u00e6, 516. cartilage corpuscles, 517. synovial membranes, 518.\nepithelium of these structures, 519. vessels of the synovial membrane, 519. serous membranes, 522.\nepithelium of these membranes, 523. basement membrane, 523.\nsubserous cellular tissue, 524. nerves, 525.\nchoroid plexus, 525. development of serous membranes, 526 development in the human f\u0153tus, 526. development by friction, 526. physiology of the serous and synovial membranes, 527. contrast of serous and synovial membranes, 528. subcutaneous and subtendinous burs\u00e6, 530. morbid anatomy, 530.\nserous and dropsical effusions, 530. physical and chemical properties found in the fluid, 531.\ninflammatory or fibrinous effusions, 532.\ncomposition of the fluid, 533.\norganisation of the effusion, 535.\nsuppurative inflammation, 535.\nchronic inflammation, 536.\nevents of inflammation, 536.\ntubercle, 537.\ncancer of the tissues, 537.\nossification, 537.\ncysts, 538.\nsubserous areolar tissue, 538. loose cartilages, 538.\nSesamoid bones, 541.\nin the human subject, 541.\nof the thumb and great toe, 541. structure, 541. development, 542. disease and injury, 542. other sesamoid bones, 542. comparative anatomy, 543. use of sesamoid bones, 543.\nSeventh Pair of Nerves, 543. facial and auditory nerves : the auditory nerve, 543 its apparent origin, 544. facial nerve, 541.\ndescription of the facial nerve, 544. in the cranium, 545. portio intermedia, 545. in the temporal bone, 545.\nsuperficial petrosal nerve, connected with the facial, 545.\nbranch from the facial to the membrane which closes the fanestra ovalis, 546. filament to the stapendius muscle, 546. the chorda tympani, 546. connexion of the facial and vagus nerves, 546. external to the cranium, 546. posterior auricular, 546. digastric branch, 547. stylo-hyoid branch, 547. tempora-facial division, 547. orbicular or supra-orbital branches, 547. infra-orbital filaments, 547. the buccal branches, 547. cervico-facial division, 548. supra-maxillary part, 548. infra-maxillary, 548.\nthe portio intermedia in the human subject, 548. general results of examinations in comparative anatomy, 550.\nphysiology of the seventh nerve, 551. the facial nerve distributed almost exclusively to muscular structures, 551.\nthe portio du ra termed by Bell the respiratory nerve of the face, 552.\nthe section of the facial nerve indirectly affects the sense of smell, 552.\neffect of division of the portio dura on the eye, 552. influence of the facial nerve on the sense of taste, 553. the facial nerve a nerve of motion, 554.\nShells the term applied to the envelopes in which the bodies and members of many animals belonging to the radiated, molluscous, and articulated sub-kingdoms are enclosed, 556. shells of the mollusca, 557. of the echinoderrnata, 566. of Crustacea, 569.\n[The diversities in the subordinate divisions of the various groups and classes will be found under their respective heads in the article.]\nShoulder Joint : Normal Anatomy, 571. deltoid muscle, 571.\nShoulder Joint : Normal Anatomy (continued). scapulo-humeral articulation, 572. the bones : glenoid cavity of the scapula, 573. head of the humerus, 573. the tuberosities, 573.\nstructures which facilitate motion in the joint, 573.\ncartilage of incrustation, 573.\nconnecting media ; capsular ligament, 574.\nlong tendon of the biceps, 575. synovial membrane, 575. mechanical functions: motion of fluxion, 576. of extension, 576. of adduction, 576. of abduction, 576. of circumduction, 577. of rotation, 577.\nShoulder Joint : Abnormal conditions of, 577. disease : acute arthritis of the shoulder, 577. symptoms of acute inflammation, 577. anatomical characters of arthritis, 577. chronic arthritis of the shoulder, 577. simple chronic arthritis, 578. symptoms, 578. cases, 578.\nanatomical characters of chronic \"rthritis, 580. cases, 581.\nchronic rheumatic arthritis, 58-*. symptoms, 584. diagnosis, 585. anatomical characters, 585. cases, 588.\nfractures : fracture of the acromion process, 600. of the coracoid process, 600. of the neck of the scapula, 601. of the superior extremity of the humerus, 601. intra-scapular fracture of the humerus, 601. extra-scapular fracture through the tubercles, 602. fracture of the superior extremity of the humerus through the line of junction of the epiphylis with the shaft of the bone, 603.\nfracture of the surgical neck of the humerus below the tuberosities and junction of the epiphylis, 605. dislocations, 605.\ndislocation downwards and inwards into the axilla, 606. symptoms, 606.\nanatomical characters of the dislocation into the axilla, 607.\ndislocation forwards, 609.\ndislocation backwards of the head of the humerus on the dorsum of the scapula, the result of accident, 611. case, 611.\ndiagnosis between the fractures of the superior extremity of the humerus and dislocations of the shoulder-joint, 613.\ndislocation of the head of the humerus sometimes combined with a fracture of the arm, 614. dislocation of the head of the humerus accompanied with a fracture of the neck of the humerus, 614. muscles : laceration of the tendon of the subscapularis muscle, 615.\needematous swelling, 615.\nparalysis of the muscles of the arm, 615.\nalterations of the nerves, 616.\nluxations of the head of the humerus complicated with a lesion of the axillary artery, 616. case, 616.\ncongenital malformation of the shoulder-joint, 617. anatomical characters of congenital malformation with displacement of the head of the humerus inwards, 618.\ncases, 618.\ncongenital malformation with displacement of the head of the humerus on the dorsum of the scapula, 619. case, 620.\nSixth Pair of Nerves, 621.\nvisible origin of the nerve, 621. connected with the sympathetic nerve, 621. physiology of the sixth nerve, 622.\nSkeleton, 622.\nlaw of unity in variety, 622. vertebrae are unequal quantities, 624. even the one vertebra is not of equal quantity in all individuals of the same species, 625. all vertebrae contain a greater or less amount of certain known elemental pieces, 625. the dorsal vertebra of human anatomy is an artificial figure, 625.\nthe cervical vertebra developes the costal appendages, 626.\nall the cervical vertebrae develope costal appendages, 627.\nthe lumbar vertebra developes the costal appendages,\nall the lumbar vertebrae develope costal appendages, 628. the sacral vertebrae develope costal appendages, 628. the coccygeal vertebrae are deprived of their costal appendages, 629.\nthe.first seven thoracic costo-vertebral figures are whole or plus quantities, 629.\nthe five asternal costo-vertebral forms are proportionals metamorphosed from five sternal costo-vertebral plus quantities, 630.","page":1535},{"file":"p1536.txt","language":"en","ocr_en":"1536\nANALYTICAL INDEX,\nSkeleton {continued).\nthe five lumbar vertebr\u00e6 are proportionals metamorphosed from five sternal costo-vertebral archetypes,\n630.\nthe sacro-coccygeal series of vertebr\u00e6 are proportionals degraded from sternal costo-vertebral circles, 631. the seven cervical vertebi\u00e6 are proportionals degraded from seven sterno-costo-vertebral whole quantities,\n631.\nthe mammalian spinal axis consists of a series of segmental quantities, whose only variety or specific distinction depends upon proportioning from the whole thoracic quantities, 631.\nuniformity of structure is a condition proper to the plus thoracic originals of the spinal axis of the mammalian body, 632.\nevery spinal segment which is lesser refers to every spinal segment which is greater, and all lesser segments refer to that which is greatest, 633. structural uniformity cannot characterise such spinal segments as are proportionally or quantitatively various, 633.\nspecific variety is none other than proportional variety,\n633.\nthe knowledge of the differential quantity between all spinal segments renders them exactly uniform in idea, 633.\nwithout knowing the full dimensions of whole or uniform quantities, we can never rightly understand the real character of lesser and special forms, and therefore can never otherwise understand the law of formation, 634.\nthe mammalian cervix is not limited to the fixed number of seven cervical vertebr\u00e6, 634. the number of ceivical vertebr\u00e6 in the mammal cervix depends upon the number of archetypal costo-vertebral figures which have suffered metamorphosis, 635.\nthe presence of cervical ribs subtracts from the number of cervical vertebr\u00e6, and adds to the number of thoracic archetypes, 636.\nthe length of the thorax depends upon the number of persistent costo-vertebral archetypes, 636. the numerical length of the lumbar spinal region depends upon the number of archetypes subjected to metamorphosis, 637.\nthe numerical length of the sacral and coccygeal series is not fixed, and this is owing to the same fact of archetypes undergoing metamorphosis, 637. a comparison of the same numerical vertebr\u00e6 in all human spinal axes will prove the truth of the present interpretation of the law which governs the development of all vertebral forms, not only in the same spine, but all other spines, 637. the anomaly is a link in the chain of form, 638. all the spinal segments of all classes and species of ver-tebrated animals are only as the variable proportionals of sterno-costo-vertebral archetypes, 638. the hyoid apparatus occurs opposite to the cervical spinal region, where we know costal quantity to be lost ; the hyoid apparatus refers to the cervical vertebr\u00e6, and consists of their ribs metamorphosed, 640. the ventral apparatus occurs opposite to the lumbar spinal region, where we understand that costal quantity is lost ; the ventral apparatus refers to the lumbar vertebr\u00e6, and consists of their ribs metamorphosed,\n643.\nclavicles, coracoid bones, and ribs are identical parts of the costo-vertebral whole quantities or archetypes,\n644.\nmarsupial bones, pubic and ischiadic bones and ribs, are identical parts of the costo-vertebral whole quantities or archetypes, 648. chevron bones and ribs are identical parts of the costovertebral whole quantities or archetypes, 650. the sternal median line ranges from the maxilla to the pubic bones of the abstract archetypal skelatal fabric, 651.\nevery fossil skeletal species of extinct animals, as well as every recent existing species of skeleton, are forms created of the archetypal skeleton, 655. the cranio-facial apparatus consists, like the thoracic apparatus, of variable proportionals of the sterno-costo-vertebral quantities, 655. the scapulary or fore-limbs of all the vertebrated animals are homologous to one another ; the variety among these organs occurs by a metamorphosis or omission of elementary quantity, 661. the scapulary and pelvic members are homologous,\nthe sterno-costo-vertebral quantity is a proportional of the dorso-ventral quantity, 667. the scapulary and pelvic pairs of limbs are proportional quantities metamorphosed from the dorso-ventral archetypes, 669.\nthe cranio-facial apparatus of segments are proportionals of the dorso-ventral archetypes, 673. the cranio-facial apparatus is the origin of the dorso-ventral archetypal series, and the caudal apparatus is its termination, 673.\nthe uniform archetypal series undergoes a graduated metamorphosis of its quantities for the production of all varieties of skeletal species, 674.\nSleep : necessity for, and nature of sleep, 677. medulla oblongata, 677. ganglia of sensation, 677-hemispheric ganglia, 677. the cerebellum, 677. sleep of plants ; of leaves, 678.\nof flowers, 679. periodicity of sleep, 679. causes of sleep, 680. phenomena of ordinary sleep, 682. access of sleep, 683.\npower of being aroused by impressions made upon the organs of sense, 683. amount of sleep required by man, 685. as age advances, 685. temperament, 685. habit, 686.\nprevious exhaustion, 686. entire absence of sleep, 686. deficiency of sleep, 686. protraction of sleep, 687.\ndreaming : entire absence of voluntary control, 687.\npeculiarities of the state of dreaming, 689. somnambulism, 691.\nreadiness with which the train of thought may be guided during the state of somnambulism, 694! causes of somnambulism, 695., mesmerism, phenomena of mesmerism, 696.\nSmell, 697.\ngeneral structure of the organ of smell, 698. the olfactive organ in other air-breathing vertebrata corresponds with that of man, 699. insects possess the olfactive power, 700. nerve of smell, 700.\nconditions of the exercise of the sense, 701. purposes of the sense, 701.\nin the air-breathing vertebrata the sense of smell is, as it were, the sentinel of the respiratory organs, 702. in man, the sense of smell is not, ordinarily, so acute as it is in many of the lower animals, 702.\nSoftening and Induration, 703. softening of the brain, 706. softening of the spinal cord, 706. induration of the brain, 706. induration of the spinal cord, 707. softening of the heart, 707. induration of the heart, 707. softening of the lungs, 707. induration of the lungs, 707. mucous, serous, and articular membranes, 708. lining membrane of the heart, 708. internal membrane of arteries, 708. softening of the arachnoid, peritoneum, and pleura, 708. softening of mucous membranes, 708. softening of the skin, 7,f*. appendages of the skin, ? l0,> induration of mucous membranes, 710.\n.indurated and thickened state of the membranes of the brain, pericardium, and pleura, 711. softening of the liver, 711. induration of the liver, 711. softening of the spleen, 711-induration of the spleen, 711. softening of the kidney, 712. induration of the kidney, 712. induration and softening of the uterus, 712. prostate gland, testicle, and epididymus, 712. osseous framework of the body, 712. softening of cartilage, 712. fibrous tissue becomes indurated, 713. softening of the muscular structures, 713. softening of cellular tissue, 713. induration of cellular tissue, 713.\nSolipeda, group of herbivorous quadrupeds, 713. genus equus : equus caballus, equus hemionus, equus asinus, equus zebra, equus quaccha, and equus mon-tanus, 714. osteology, 715.\ncervical vertebr\u00e6, 716. dorsal vertebr\u00e6, 717. vertebr\u00e6 of the loins, 718. csudal vertebr\u00e6, 718. thorax, 718. ribs, 718.\nanterior extremity, 718. scapula, 718. humerus, 718. forearm, 718. carpus, 718. metacarpal bones, 719. posterior extremity, 719. pelvis, 719. leg, 720. fibula, 720.\nbones of the tarsus, in the horse, 721. of the metatarsus, 721. myology, 721.\npanniculus carnosis, 721. proper muscles of the spine, 722. the tail ; muscles which raise or strengthen the tail, 753.\nmuscles which depress the tail, 723. muscles adapted to move the tail laterally, 724.","page":1536},{"file":"p1537.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\t1537\nSolipeda (continued).\nmuscles derived from the spinal column which serve immediately for the movements of the cranium, 724.\nmuscles arising from other cervical vertebrae, 724. muscles of the ribs and sternum, 724. walls of the abdomen, 725. anterior extremity ; muscles of the shoulder, 725. muscles inserted in the humerus, 726. muscles of the forearm, 727. extensors, 727.\nmuscles of the carpus and metacarpus, 727. muscles of the hand (extensor communis digit-orum), 728.\nposterior extremity ; muscles of the pelvis, 729. muscles inserted in the os femoris, 729. flexor muscles of the leg, 729. extensor muscles of the thigh, 729. muscles implanted into the foot, 730. muscles implanted into the digit, 730. flexor muscles, 731. extensor muscles of the toes, 731. muscles which act immediately upon the lower jaw, 731.\nmuscles of the os hyoides, 731. muscles of the tongue, of the palate, and of the larynx, 732.\nmuscles of the face, 732. depressor of the lower eye-lid, 732. long dilator of the nostril, and elevator of the upper lip, 732.\nalimentary apparatus ; teeth, 732. salivary glands, 734. parotid glands, 734. submaxillary glands, 734. sublingual glands, 734. pharynx, 734. stomach, 735. liver, 736. spleen, 736. pancreas, 737. circulatory apparatus, 737. structure of the horse\u2019s foot, 737.\t*\nhorny hoof, 737. the sole, 739.\ncartilages of the foot, 740. soft parts of the foot, 741. nervous system and organs of the senses, 741. organs of generation ; male organs, 742. scrotum and penis, 742. testicles, 742.\nfemale organs of generation, 743. urinary bladder, 743. orifice of the uterus, 743. ovaria and fallopian tubes, 743. gravid uterus, 743. the hippomanes, 744. mammary glands, 744.\nSpinal Accessory Nerve, 745. internal branch, 748. external branch, 748.\ncomparative anatomy of the spinal accessory, 748. physiology of this nerve, 749.\nSpinal Nerves, 750.\nposterior branch of the first cervical or sub-occipital nerve, 750.\nposterior branch of the second cervical nerve, 750. posterior branch of the third cervical, 751. horizontal branch. 751.\nposterior root of the fourth cervical nerve, 751. posterior branches of the fifth, sixth, seventh, and eighth cervical nerves, 751. posterior branches of the seventh and eighth cervical nerves, 751.\nposterior branches of the dorsal (thoracic) nerves, 751. external or muscular branches of the eight superior, 751.\nthe internal branches, 751. external branches of the four inferior, 751. internal branches of the four inferior, 751. posterior branches of the lumbar nerves, 752. external branches, 752. posterior branches of the sacral nerves, 752. anterior branches of the spinal nerves, 752. anterior branch of the first cervical nerve, 752. anterior branch of the second cervical nerve, 752. anterior branch of the third cervical nerve, 752. anterior branch of the fourth cervical nerve, 752. cervical plexus, 752. superficialis colli, 753.\nthe ascending branch, 753. the descending branch, 753. the auricularis magnus, 753. superficial branch, 753. deep branch, 753-the occipitalis minor, 753. supra-clavicular and acromial nerves, 753. acromial nerves, 753.\ncommunicating branches, 753. internal descending cervical, 753. phrenic nerve, 754.\nright phrenic, and the left, 754.\nVOL. IV.\nSpinal Nerves (continued).\nanterior branches of the four inferior cervical and first dorsal nerves, 754. the brachial plexus (axillary), 754. nerve for the rhomboideus, 755. nerve to the serratus magnus, 755. nerve for the subclavius, 755. supra-scapular nerve, 755. subscapular nerves, 755. nerves for the subscapularis, 755. internal cutaneous, 755.\nexternal terminal branch, 755. internal branch, 756.\ncutaneous nerve of Wrisberg (the accessory nerve of the internal cutaneous), 756. external cutaneous, 756. branches to the biceps, 756. branches for the brachialis anticus, 756. median nerve, 756. muscular branches, 756. anterior interosseous nerve, 756. palmer cutaneous branch, 757. terminal digital branches of the median, 757. first digital nerve, 757. second digital nerve, 757. third digital nerve, 757. fourth digital nerve, 757. the ulnar nerve, 757.\nsuperficial external, 758. deep branch, 758. musculo spiral nerve (radial), 758. internal cutaneous, 759.\nbranch for the internal head of the triceps, 759. branch for the outer head of the triceps and anco-n\u00e6us, 759.\nexternal cutaneous branch, 759. anterior terminal branch, 759. internal branch, 759. deep terminal branch, 759. circumflex nerve (axiliary), 759.\nanterior branches of the dorsal (intercostal) nerves, 760.\nintercostal branches, 760. first dorsal nerve, 760. second dorsal nerve, 760. cutaneous branch of the third dorsal, 760. cutaneous branches of the fourth and fifth dorsal nerves, 760.\ntwelfth dorsal nerve, 761.\nanterior branches of the lumbar nerves, 761.\nthe lumbar or lumbo-abdominal plexus, 761.\nupper musculo cutaneous, 761.,\nlower musculo cutaneous, 762f~\ngenito-crural nerve, 762.\ncrural nerve (femoral), 762.\ninternal cutaneous nerve, 762.\naccessory saph\u00e6nus nerve, 763.\nmiddle cutaneous nerve, 763.\nnerve to the femoral vessels, 763.\nbranch for the vastus internus, 763. branch for the erur\u00e6us, 763. branch for the rectus, 763. branch for the vastus externus, 763. saph\u00e6nus nerve, 764. obturator nerve, 764.\nanterior branches of the sacral nerves, 765. sacral plexus, 765.\nnerve for the obturator internus, 766. internal pudic nerve, 766.\nsuperior branch (dorsal nerve) of the penis, 766. inferior branch (perin\u00e6al), 766. pudic nerve, 766. superior glut\u00e6al nerve, 766. inferior glut\u00e6al nerve (lesser sciatic), 766.\ncutaneous branch to the back of the thigh and upper part of the leg, 767. nerve for the pyriformis, 767. nerves for the gemelli and quadratus femoris, 767. great sciatic nerve, 767. nerve for the semi-tendinous, 767. semi-membranosus, 761. peroneal nerve (external popliteal), 768. peroneal cutaneous, 768. peroneal saph\u00e6nus, 768. superior external articular, 768. inferior external articular, 768. anterior tibial nerve, 768. musculo-cutaneous nerve, 769. tibial nerve, 769.\nterminal branches, 770. internal plantar nerve, 770. external plantar nerve, 771.\nSpleen: situation and form, 771. varieties of the spleen, 771-size and weight, 771. consistence, 772. structure, 772.\nserous membrane, 772. fibrous coat, 772. trabecular tissue, 773. splenic or malpighian corpuscles, 775. red spleen substance ; the spleen-pulp ; parenchyma of the spleen, 780.\n5 F","page":1537},{"file":"p1538.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\n1538\nSpleen (continued).\ncells of the spleen-pulp, 780. the blood effused in the spleen-pulp, 781. cells in mammals, 783. in birds, 783. in reptilia, 783. in fishes, 784.\nblood-vessels of the spleen ; splenic artery, 787. splenic vein, 788. lymphatics of the spleen, 793. nerves, 794.\nfunction of the spleen, 796. morbid anatomy, 800. enlargement, 800. inflammation, 801.\nStatistics, Medical, 801.\nof facts considered as the elements of statistical inquiries, 804.\nof the average and extreme results deduced from observation, 806.\nof extreme values derived from observation, 813. Statistics, Vital. See Vital Statistics.\nStomach and Intestinal Canal. See Supplement.\nSubclavian Arteries, 814. subclavian vein, 815.\nfirst stage of the right subclavian artery, 815.\nanterior relations, 815. first stage of the left subclavian artery, 816. differences between the right and the left subclavian arteries in their first stage, 816. relations of the left artery, 816. subclavian arteries in their second stage, 8i7. subclavian artery in its third stage, 817. anomalies in the origin of the subclavian arteries, 818. branches of the subclavian arteries, 819. vertebral artery, 819.\nrelations, 820. basilar artery, 820. branches of the basilar artery, 821.\ninferior (or posterior) cerebellar artery, 821. superior (or anterior), 821. posterior artery of the cerebrum, 821. varieties occasionally observable in the vertebral arteries, 822. vertebral vein, 822. internal mammary artery, 822. branches of the mammary artery, 822. varieties, 823.\ninferior thyroid artery, 823. relations, 823. branches, 824. supra-scapular artery, 824. arteria transversalis colli, 824. arteria cervicalis profunda, 824. superior intercostal artery, 824. operative proceedings, 825.\nSupra-Renal Capsules, 827. in man, 827-\nin mammalia, birds, reptiles, and other vertebrata. 828.\nminute structure, 830. cortical substance, in man, 841. medullary substance, 832. accessory supra-renal capsules, 832. supra-renal blood-vessels in the human subject, 833.\nthe veins, 833. lymphatics, 833. nerves, 833. in mammalia, 833. in birds, 834. in reptilia, 834. in fishes, 835. development, 836. physiology, 837.\nSweat, 841.\nin the healthy human subject, 841. observations made by Linings in the climate of South Carolina, 842.\nexperiments made by Mr. Cruikshank and by Mr. Abernethy, 842. by Lavoisier and Seguin, 842. gases which pass off from the body by insensible perspiration, 842. experiment by Simon, 843\nsweat analysed by Berzelius and by Anselmino, 843. sweat in disease, 844.\nSymmetry, an anatomical signification that one half of an animal is usually an exact reversed copy of the other, 845.\nlateral repetition, 845.\nin man, exceptions are offered by the heart, great blood-vessels, lungs, bowels, liver, spleen, &c., 846. abnormal deviations from symmetry, 848. comparative anatomy, 848. in all mammalia, 848. \\ in birds, 848. in reptiles, 848. in fishes, 849. in articulata, 849.\nin mollusca and other animals, 850. antero-posterior symmetry, 851.\nSymmetry (continued).\nsymmetry of disease, 851. plants, 852. crystals, 852.\nSympathetic Nerve. See Supplement.\nSympathy, the assumption by different individuals, or by different parts of the same* individual, of the same or an analogous physiological or pathological state at the same time, or in rapid succession, 852. sympathetic sensations, 853.\nmovements excited by a stimulus applied at a distance, 853.\nsympathetic phenomena 854, continuous and contiguous sympathy, 855.\nSynovia, the fluid that exists within the membrane lining joints to assist motion by lubrication, 856. synovia chemically examined, 856.\nTaste, the sense by which we distinguish the sapid properties of bodies, 856. seat of the sense, 857-conditions of the sense, 857. nerves of taste, 858. speciality of the nervous fibres, 859. gustative papill\u00e6, 860. conical and filiform papill\u00e6, 860. exercise of the sense, 861.\ninfluence of habit in blunting the sensibility to particular tastes, 862.\nsense of taste affected by illness, 862. purpose of the sense, 863.\nTeeth ; comparative Anatomy, 864. dentine tissue, 865. crusta petrosa, or cement, 865. enamel tissue, 865.\ncharacteristic examples in the teeth of various animals, 865.\nthe dental system of fishes, 873. number and form, 873. situation, 875. substance, 877. development, 880. dental system of reptiles, 882.\nsituation and attachment, 883. substance and structure, 884. development, 885. poisonous serpents, 887. crocodilia, 895.\ndental system of mammals, 898. tusk of the elephant, 923.\nTemperament ; a term (of ancient date) referable to peculiarities in the constitution of an individual, 935. sanguine temperament, 936. melancholic temperament, 936. nervous temperament, 936.\nTemporo-Maxillary Articulation, 937. in the human subject, 937. bones, 937.\ninterarticular fibro cartilage, 937. synovial burs\u00e6, 937. ligaments ; external lateral, 937. internal lateral, 938. stylo maxillary, 938. muscles, 938. motions of the joint, 938. of the jaw, 938.\nabnormal conditions of the temporo-maxillary joint ; accidents, 938.\nwhen both of the condyles are dislocated, 938. when one condyle only is dislocated, 939. congenital malformation, 939. disease ; chronic rheumatic arthritis, 939.\nanchylosis, 939. comparative anatomy, 940. in aves, 941. reptilia, 941. pisces, 941.\nhomology of the joint, 941.\nTeratology ; doctrine of congenital deformities, 942. original malformation of the germ, 942. cause in the mother, 942. in the father, 942.\ndeformity of the originally well-formed germ, 942.\ncyclopia, 944. 967. malformation of the ovum, 946.\nmola botryoides or hydatica, 946. separation of the placenta into lobes, 946. vessels of the umbilical cord separated near the placenta, 947.\numbilical cord too long, 947. umbilical cord too short, 947. absence of one of the umbilical arteries, 947. increased number of the vessels of the cord, 948. persistence of the umbilical vesicle, 948. constriction of the umbilical cord, 948. umbilical cord too thick, 948. malformations of the f\u0153tus, 948.\nnon-closure of the anterior part of the body, 948.\nfissure of the while anterior wall of the body, 949.\nfissure of the thorax, 949.\nectopia of the heart, 949.\nfissure of the anterior abdominal wall, 950.\ncomplete ectopia of the abdominal viscera, 950.","page":1538},{"file":"p1539.txt","language":"en","ocr_en":"1539\nANALYTICAL INDEX.\nTeratology (continued).\ncongenital umbilical hernia, 950. congenital ventral hernia, 950. acquired umbilical hernia, 950. fissure of the pubic and hypogastric regions, 950. formation of a cloaca, 950. congenital fissure of the urinary bladder, 951. ectopia vesic\u00e6 urinari\u00e6, 952. inversio vesic\u00e6 urinari\u00e6, 952. cervical fissure, 953. fissure of the face, 953. complete fissure of the face, 953. hare-lip, double, 953. single, 953.\nfissure of the palate without a hare-lip, 953. fissure of the under lip, 954. fissure of the skull, 954.\nwant of the brain and exposure of the basis of the skull, 954.\ndenuded surface of the basis cranii occupied by a spongy substance, instead of brain, 955. surface of the basis cranii only partially denuded,\n955.\nskull flat, more evolved, but having an opening, through which the brain '.protrudes as a hernia,\n956.\nfissure of the back part of the t ody, 957. hydrocephalus congenitus, 958. hydrocephalus externus, 960. acephali, or f\u0153tus without a head, 960. acephali in the form of a rounded mass without extremities, 960.\nacephali in same form, with indication of feet, 960.\nacephali in which the trunk is more developed, without a head and thoracic extremities, 961. acephali without a thorax and without superior limbs, and composed of an abdomen, genital organs, and inferior limbs, 961. acephali in which the trunk is more developed, with an imperfect thorax, 961 acephali with a trunk composed of a thorax and an abdomen, with superior and inferior limbs, 962. acephali in which some cranial bones are found, 962.\nbody and extremities perfectly developed, having a neck surmounted by the ears, 962. acephali composed of the trunk only, without indication of limbs, 962.\nwant, and defective formation, of the trunk, 963. sympodia, 964.\noriginal defective formation of the pelvis, 965. defective development of the spinal column, 965. defective formation of the extremities, 965. want of all the extremities, 965. want of the intermediate parts in the extremities, 966\nlimbs too short, 966. limbs which seem to be truncated, 966. diminished number of fingers and toes, 966. coalesced fingers and toes, 966. deficiency of the under jaw, 967. total defect of the opening of the mouth, 967. opening of the mouth represented by a fissure of the face, 967.\ntoo short an under jaw, 967. f\u0153tus in f\u0153tu : a f\u0153tus more or less perfect contained in the cavity of the body of its twin brother, or sister, 967.\nthe more or less developed rudiments of a f\u0153tus adhering, in the form of a tumour, to the external surface of a second body, 968. double monsters, in which one of the fetuses is more or less perfect, and the other merely an appendix to it, 968.\ndouble monsters : anterior duplicity, 969. lateral duplicity, 970. inferior duplicity, 972. posterior duplicity, 972. superior duplicity, 972.\nTesticle (Human Anatomy), 976. protective parts or tunics, 976. tunica albuginea, 977. glandular or secreting structure, 977-tubuli seminiferi, 978'. rete testis, 979-excretory paits,'979. vasculum aberrans, 980. vas deferens, 980.\nvessels and nerves ; spermatic vessels, 981. absorbents, 982. nerves, 982.\ntesticle in the fetus, and its passage into the scrotum, 982.\nfunctions of the testicle, 984.\ninfluence of the testicles and brain upon each other, 985.\nenvelopes of the testicle, 986.\nsuperficial or external spermatic fascia, 986.\ncremaster muscle, 986.\ndeep spermatic fascia, 986.\nspermatic cord, 986.\n[For Comparative Anatomy, see the article Organs of Generation.]\nAbnormal Anatomy oj the Testicle, 986.\ncongenital imperfections and mal-formations ; numerical excesses and defects, 986. instances of monorchides, 987.\ndeficiencies and imperfections of the vas deferens, 987-\nimperfect transition, 988.\npassage of the testicle into the perineum, 990\npassage of the testicle through the curling ring, 990.\ninversion of the testicle, 991.\natrophy of the testicle, 991.\narrest of development, 991.\nwasting, 992.\nall those causes which produce decay in other parts likewise occasion wasting of the testicle, 992. inflammation of the tunica vaginalis, or acute hydrocele, 994.\nhydrocele of the tunica vaginalis, 995. multilocular hydrocele, 996.\nhydrocele, generally single, sometimes occurs on both sides, 996.\ncongenital hydrocele, 996 encysted hydrocele of the testicle, 997. encysted hydrocele of the tunica vaginalis, 998. spermatozoa in connexion with encysted hydrocele of the testicle, 998.\ndiffused hydrocele of the spermatic cord, 999. encysted hydrocele of the spermatic cord, 1000. complications of hydrocele, 1001. h\u00e6matocele, 1002.\nencysted h\u00e6matocele of the testicle, 1003.\nh\u00e6matocele of the spermatic cord, 1003.\nencysted h\u00e6matocele of the spermatic cord, 1003.\t1\norchitis, 1004.\nacute orchitis, 1C04.\nchronic orchitis, 1006.\nsyphilitic orchitis, 1008.\ntubercular disease, 1008.\ncarcinoma ; scirrhous disease of the testicle, 1009.\nencephaloid cancer, 1009.\ncolloid and melanosis.cancer, 1010.\ncystic disease, 1010.\nossifie deposits in the testicle, 1011.\nloose bodies in the tunica vaginalis, 1011.\nfetal remains in the testicle, 1011.\nvaricocele, 1011.\nadipose tumours, 1012.\nmorbid anatomy of the scrotum, 1013.\nelephantiasis, 1013.\nhypertrophy, 1014.\ncancer scroti, or chimney-sweeper\u2019s cancer, 1014. melanosis, 1016. fibrous tumours, 1017.\nThorax, 1017-\nclassification of the respiratory movements in animals, 1018.\nfirst kind of respiratory movements ; infusoria, 1018. second species of respiration ; insects, 1019. third species ; fishes, 1019. fourth species; amphibia,1020. fifth species; birds, 1021. sixth species ; mammalia, 1021. of the thorax in man ; anatomy of the frame-work of the thorax, 1022. dorsal vertebr\u00e6, 1022. inter-vertebral disks, 1022. sternum, 1022.\nanterior or cutaneous surface of the sternum, 1023. posterior surface, 1022. borders of the sternum, 1023. clavicular extremity, 1023. inferior extremity of the sternum, 1023. structure of the sternum, 1023. development or ossification of the sternum, 1023. ossification of the body, or the second, third, fourth, and fifth pieces, 1024.\nunion of the points of ossification of the body of the sternum, 1024.\nossification of the appendix, 1024. of the ribs, 1024. classification of the ribs, 1025. general character of the ribs, 1025. surfaces, 1025. borders, 1025. extremities, 1026. body, 1026. curve, 1026.\narch or general bend of the ribs, 1026. curves of torsion of the ribs, 1026. articulations of the ribs, 1027. position of the ribs, 1027., structure, 1027. development, 1027. special characters of the ribs, 1027. length, 1028. weight, 1029.\ntorsion (special characters), 1029. surfaces (special characters), 1030. specific differences of the extremities of the ribs, 1030.\nhead, 1030. neck, 1030. tubercle, 1031. angle, 1031.\n5 F ?","page":1539},{"file":"p1540.txt","language":"en","ocr_en":"1540\tANALYTICAL INDEX.\nThorax {continued).\ngroove, 1031.' costal cartilages, 1031.\ngeneral characters of the costal cartilages, 1031. differential characters, 1031. liability of the costal cartilages to ossify, 1031. ligaments of the ribs, 1032.\nwith the bodies of the vertebr\u00e6, 1032. with the transverse processes of vertebr\u00e6, 1032. characters peculiar to certain costo-vertebral articulations, 1032. with the sternum, 1032. characters peculiar to chondro or costo-sternal articulations, 1032.\nconnexion of the ribs with their cartilages,1033. articulations of the costal cartilages one with the other, 1033.\nligaments of the sternum, 1033. of the thorax in general, 1033.\nboundaries of the thoracic cavity, 1034. contents of the thorax, 1035. shape of the thorax, 1035. external thorax, 1035.\nanterior or sternal region, 1035. posterior or vertebral region, 1035. lateral or costal region, 1035. internal conformation of the thorax, 1036. anterior region, 1036. posterior region, 1037. lateral region, 1037.\nconformation as affected by age and sex, 1037. conformation as affected by disease and occupation, 1038.\npigeon or chicken breast, 1039. dimensions of the thorax, 1040. external measurement, 1040. internal measurement, 1040. of the respiratory muscles, 1042. intercostal muscles, 1042.\nintercostales externi, 1043. intercostales interni, 1043. action of the intercostal muscles, 1044. movement of the levers, 1047. effect of tensions, oblique, perpendicular, and decussating, between the moveable levers or ribs, 1050.\nof the degree of obliquity of a tension, 1052. of the obliquity of the ribs or bars with reference to the spine, 1053.\nof oblique tensions in contrary directions, 1053. of tenisons at different parts of the bars or ribs, 1054.\naction of the intercostal muscles (resumed), 1055. levatores costarum, 1055. triangularis sterni, 1055. infra-costales, 1056. of the elasticity of the ribs, 1056. of the elastic power of the lungs, 1058. of the muscular contractility of the lungs, 1060.' of respiratory muscular power, 1060. of the respiratory volumes, 1064. residual air, 1065, 1066. reserve volume, 1067. breathing volume, 1067. complemental volume, 1067. vital capacity volume, 1067. vital capacity, 1068.\neffect of height, 1070. affected by position of the body, 1073. affected by weight, 1073. relation of vital capacity to the circumference of the thorax, 1077. vital capacity affected by age, 1077. affected by disease, 1078. of the respiratory movements, 1079. ordinary breathing, 1080. deep inspiratory, 1081. deep expiratory, 1082.\nchange of position by extreme breathing, 1082. of ordinary breathing, 1082. extraordinary breathing in both sexes, 1082. pathological respiratory movements, 1083. limited breathing movement, 1084. non-symmetrical breathing, 1084. reversed breathing, 1084. massive breathing, 1084. interrupted breathing, 1084. partial breathing, 1084.\n* quick and slow breathing, 1085. irregular breathing, 1085. double breathing, 1085.\nof the number of respirations in a given time, 1085\nrelative velocity of the breathing and the pulse, 1085.\nsudden change in atmospheric pressure, 1086. of the sounds of respiration, 1086.\nThymus Gland, 1087.\nhuman anatomy, 1087.\nrelative situation, 1088. development, 1090. mature structure of the gland, 1090. oontents of the thymic cavities, 1093.\nThymus Gland (continued).\nearly development, 1094. development of size, 1095. comparative anatomy, 1095. mammalia, 1095. cheiroptera, 1095. insectivora, 1096. carnivora, 1096. marsupialia, 1096. among rodents, 1096. in edentata, 1097. monotremata, 1097. pachydermata, 1097. ruminantia, 1097. aves, 1097. reptilia, 1098. pisces, 1099. physiology, 1099.\nmorbid anatomy : absence of the gland, 1101. inflammation, 1102. atrophy, 1102. hypertrophy, 1102.\nThyroid Gland, 1102.\nsize, 1102. form, 1102.\nsituations and relations, 1103. colour, 1103. structure, 1104. contents of the cavities, 1105. vessels : arteries, 1106. capillary plexus, 1107. lymphatics, 1107. nerves, 1107. development, 1107 ! comparative anatomy, 1108. birds, 1108. reptiles, 1108. fishes, 1109. , morphology, 1111. morbid anatomy, 1114.\ninflammation, 1114. alterations of structure, 1114. melicerous degeneration, 1114 adventitious formations, 1116. carcinomatous growths, 1116. encephaloid or scirrhus, 1116. enlargement of the vessels, 1116. history of investigations, 1117.\nTibio-fibular Articulations, 1117.\nsuperior tibio-fibular articulation, 1118. ligaments, 11)8.\nanterior ligament, 1118. posterior ligament, 1118. tendon of the biceps, 1118. synovial membrane, 1118. inferior tibio-fibular articulation, 1119. anterior ligament, 1119. posterior ligament, 1119. interosseous ligament, 1119. * mechanism of the articulations, 1119. dislocation of the fibula at the upper tibio-fibular articulation, 1119.\nTongue, 1120.\nhuman anatomy, 1120. size, 1120. direction, 1120. shape, 1120.\ngeneral description, 1120. superior surface, 1121. inferior surface, 1122. anterior extremity, apex, or point, 1122. posterior extremity or base, 1122. the basis or framework of the tongue, 1123. hyoid bone, 1123.\nhyoglossal membrane or ligament, 1124. median fibrous septum, 1124. investments, 1124. muscular system, 1125. intrinsic muscles, 1125.\ntransverse lingual, 1126. vertical lingual, 1126. superior lingual, 1126. lateral lingual, 1126. inferior lingual, 1126.\nmode of termination of the intrinsic fibres, 1131. extrinsic muscles, 1132. palatoglossus, 1132. styloglossus, 1132. hyoglossus, 1133. genioglossus, 1133. accessory extrinsic muscles, 1134. movements of the tongue, 1134.\nas affecting its length, 1134. as affecting its direction, 1134. tegumentary system, 1135. cutis, 1135.\nbasement membrane, 1135. epithelium, 1135.\npapillary structure of the tongue, 1136. circumvallate papillae, 1136. fungiform papill\u00e6, 1137. conical or filiform papill\u00e6, 1138. simple papill\u00e6, 1139.","page":1540},{"file":"p1541.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\t1541\nTongue (continued).\nfunctions of the different papilla?, 1140. mucous glands, 1140. vessels of the tongue 1141. nerves of the tongue, 1141. comparative anatomy, 1141. mollusca, 1142. cephalopoda, 1143. vertebrata, 1143., hyoid apparatus, 1144. in fish, 1144. in birds, 1145. in mammalia, 1146. pisces, 1146. reptilia, 1146. aves, 1150. mammalia, 1151.\nthe functions of the tongue, 1151. prehension, 1151. mastication, 1152. insalivation,.1152. deglutition, 1152. speech, 1153.\nmorbid anatomy of the tongue, 1153. inflammation, 1153. suppurative glossitis, 1153. erectile glossitis, 1153. mercurial glossitis, 1154. ulceration of the tongue, 1154. dyspeptic ulceration, 1154. aphthous ulceration, 1155. indurated non-malignant ulceration, 1155. gangrenous ulceration, 1156. syphilitic ulceration, 1156. rhagades or fissures, 1156. glossy tubercle, 1156. phaged\u00e6nic syphilitic ulcers, 1156. cancer of the tongue, 1157. tumours of the tongue, 1157. fatty tumours, 1157. encysted tumours, 1157. mulberry-like tumour, 1158. polypus-like tumour, 1158. hypertrophy and prolapsus of the tongue, 1158. atrophy of the tongue, 1159. diseases of the papillae, 1159. hypertrophy of papillae, 1159. atrophy of the papillae, 1160. effusions into papillae, 1161. lymph, 1161. denuded papillae, 1161. fur, 1161. tongue-tie, 1162. tongue swallowing, 1162. adhesions of the tongue, 1162. necrosis of the hyoid bone, 1162.\nTouch, 1163.\ngeneral sensibility, 1163. special organs of touch, 1165. conditions of the sense, 1167. tactile discrimination, 1168. sense of temperature, 1171. muscular sense, 1172. sense of weight, 1175. sense of direction, 1175.\nmental phenomena connected with the sense, 1176. unprovability of the sense of touch, 1177. morbid conditions of the sense, 1182. anaesthesia, 1182. hyper\u00e6sthesia, 1184. depravation, 1184.\nTunicata, 1185.\ndivisions and subdivisions into families and genera, 1186.\nanatomy and physiology of the tunicata, 1193. anatomy of the asciadiat\u00e6, 1200.\nof the clavellinid\u00e6, 1213. of the botryllid\u00e6, 1218. of pyrosoma, 1227. of salpae, 1230. of pelonaia, 1239. locomotion of the tunicata, 1240. affinities of the tunicata, 1241.\nUrethra, 1244. in the male, 1244.\ndirection, 1244. length, 1244. diameter, 1245. prostatic portion, 1246. membranous portion, 1247. triangular ligament, 1247. spongy portion, 1248. bulb, 1248.\nmucous membrane, 1249. lacunae ; lacuna magnus, 1250. structure, 1250.\nCowper\u2019s glands, 1252.\ncomparative anatomy, 1253. blood-vessels of the urethra, 1254. arteries, veins, 1254. nerves, 1254. lymphatics, 1254. function, 1254.\nUrethra {continued).\ndevelopment, 1255. pathology, 1256.\ncongenital malformations, 1256. epispadias, 1256. hypospadias, 1256. deviationsjn diameter, 1256. diseases and accidents, 1256.\nthe urethra deviates frequently from its normal direction, 1257. solutions of continuity, 1257. inflammation, 1257-ulceration, 1259. abscesses, 1259. tubercles, 1259. spasmodic stricture, 1260. permanent stricture, 1260. varieties of permanent stricture, 1260. false passages, 1261. fistula? in perin\u00e6o, 1261. causes of stricture, 1262. co-existence of stone with stricture, 1262. diseased lacunae, 1262. obstructions from other causes, 1262. irritable urethra, 1263. neuralgia of the urethra, 1263. in the female, 1263.\t*\nmeatus urinarius, 1264. organisation, 1264. prostate gland, 1265. pathology, 1265. comparative anatomy, 1267.\nUrine, 1268.\nurea,1269.\nextractive matters of urine, 1269.\nanimal extractive soluble in water only, 1269.\ncolouring matter, 1270.\nmucus. See article Mucus.\nuric or lithic acid, 1270.\nhippuric acid, 1270.\nlactic acid, 1271.\nquantitative composition of healthy urine, 1271. urine of animals, 1279.\nlion, tiger, and leopard, 1279.\nhorses, 1279.\noxen, cow, 1280.\ncamel, 1280.\npigs, 1280.\ngoat, 1280.\nbeaver, 1280.\nrabbits and guinea-pigs, 1281. birds, 1281. rattle-snake, 1281. bull-frog, 1281. land-tortoise, 1281.\nurine in disease ; human subject, 1281. lithic acid deposit, 1282. deposit of lithates, 1282. deposit of earthy phosphates, 1283. deposit of oxalate of lime, 1283. deposit of cystine, 1283. carbonate of lime deposit, 1283. hippuric acid, 1283. calculi : lithic acid calculi, 1287.\nmulberry or oxalate of lime calculi, 1287. cystic oxide calculi, 1287. phosphatic calculi, 1287. alternating calculi, 1288. mixed or compound calculi, 1288. diseased condition of urine, 1289. febrile urine, 1289. anaemic urine, 1289. alkaline urine, 1289. urine nearly normal, 1289. diseases: phlebitis uterina, 1291. meningitis, 1291. encephalitis, 1291. delirium tremens, 1291. myelitis, 1291. bronchitis, 1291. pneumonia, 1291. pleuritis, 1291. empyema, 1291. hepatitis 1291. nephritis, 1291.\nchronic nephritis, albuminous nephritis, mor bus brightii, 1291. cystitis, 1292. typhus. 1292. intermittent fever, 1292. cholera, 1292. rheumatism. 1293. phthisis, 1293. struma, 1293. diabetes mellitus, 1293. diabetes insipidus, 1293. diabetes chylosus, 1293. jaundice, 1293. urine of pregnancy, 1294. foreign substances in the urine, 1294.\nVarieties of Mankind, 1294.\ndistinctive characteristics of man, 1294. his two hands, 1294.","page":1541},{"file":"p1542.txt","language":"en","ocr_en":"ANALYTICAL INDEX.\n1542\nVarieties of Mankind (continued), erect attitude, 1295. cranium, 1295. position of the face, 1296. vertebral column, 1296. length of lower extremities, 1296. biped progression, 1279. knee joint, 1279. arched form of the foot, 1297. form of the trunk, 1297. visceral apparatus, 1297. conformation of the brain, 1299 man\u2019s senses subordinated to his intelligence, 1300.\ncapacity for intellectual progress, 1300. species and varieties, zoologically considered, 1301. diversities of age have led to the establishment of species which have no existence in nature, 1302.\ninfluence of external conditions in modifying the conformations both of plants and animals, 1303. tendency to spontaneous variation exists in many races, 1304.\ngeneral survey of the diversities, in physical and psychical characters, presented bv different races of mankind, 1315.\nanatomical differences by which the several races of mankind are distinguished from each other, 1319. conformation of the cranium, 1319. prognathous type, 1321. pyramidal type, 1322. oval or elliptical type, 1323. conformation of the pelvis, 1331. conformation of the other parts of the skeleton 1331.\ncolour of the skin, 1333.\ncolour, \u2019texture, and mode of growth of the hair, 1337.\nphysiological conformity or diversity of the several races, 1339.\naverage duration of life, 1339. epoch of the first menstruation, 1339. frequency of the catamenial flux and the epoch of life to which it extends, 1341. duration of pregnancy, 1341. fertility of hybrid races, 1341. psychical comparison of the various races of mankind, 1342.\nphilological evidence of a common origin, in language, 1345.\naptotic type, 1346. agglutinate type, 1346. amalgamate type, 1346. anaptotic type, 1346.\nprincipal groups of various languages, 1347. general survey of the principal families of mankind, 1348.\nEuropean nations, 1348.\nAsiatic nations, 1348.\nAfrican nations, 1352.\nAmerican nations, 1358.\nOceanic nations, 1361. addendum, 1365.\nVein, 1367.\nliterary history, 1367. structure, 1368.\nepithelium, 1369. fenestrated membrane, 1370. internal tunic of longitudinal fibres, 1371. middle coat of intermixed Circular and longitudinal fibres, 1372.\nexternal coat of longitudinal fibres, 1373. minute veins, 1373.\nveins at their junction with the heart, 1375. cavae, passing through the diaphragm and pericardium, 1376. cerebral sinuses, 1376. umbilical vein, 1376. venous valves, 1377. structure of valves, 1379. fibrous lamina, 1379. sinuses in the walls of the veins, 1380. office of valves, 1381. vasa vasorum, 1381. nerves of veins, 1382. comparative structure, 1382. caudal venous heart of eel, 1383. physical and vital properties, 1384. vital contractility, 1384. venous tonicity, 1385.\ngeneral remarks upon veins: origin, Course, anasto-moses, plexuses, &c., 1385. origin of veins, 1386. course, anastomoses, plexuses, 1386i function of veins, 1389.\ncirculation in the veins, 1389. as diverticula and reservoirs of blood, 1389. venous absorption, 1390. development of veins, 1390 as capillaries, 1390. morbid anatomy of veins, 1391. phlebitis, 1392.\nVein (continued).\nsuppurative phlebitis, 1394. obliteration of veins, 1395. healing of wounds in veins, 1395. effects of ligatures on veins, 1396. phlebectesis ; varix, 1397. varices of the leg, 1398. varicocele, 1399. h\u00e6morrhoids, 1399. rupture or perforation of veins, 1399. affections of the valves of veins, 1400. phlebolites, 1400.\ncalcareous degeneration of veins, 1402. fatty tumours, 1402. entozoa in veins, 1402. distoma hepaticum, 1402.\nVenous System, 1403.\npulmonary veins, 1403. systemic veins, 1404.\nveins which form the vena cava superior. 1404. facial vein, 1404. temporal vein, 1405. superficial temporal veins, 1405. middle temporal veins, 1405. internal maxillary vein, 1405. temporo-maxillarv, 1405. occipital vein, 1405.\nveins of the neck ; external jugular vein, 1405. anterior jugular vein, 1405. internal jugular vein, 1406. collateral branches, 1406. vertebral vein, 1406.\n. spinal veins, 1406.\nveins of the upper extremity, 1406. superficial veins, 1406. radial or external superficial veins, 1406. ulnar or internal superficial, 1407. basilic vein, 1407.\ndeep veins of the upper extremity, 1407._ satellite veins of the brachial artery, 1407. subclavian vein, 1407. brachio-cephalic veins, 1408. collateral branches, 1408. inferior thyroid veins, 1408. internal mammary veins, 1408. vena cava superior, 1408. azygos veins, 1409. veins of the spine, 1409. superficial spinal veins, 1410. deep spinal veins, 1410.\nveins which form the inferior vena cava, 1411. veins of the lower extremities, 1411. superficial veins, 1411. internal or long saphena vein, 1411. posterior or external saphena vein, 1411. deep veins of the lower extremity, 1411. femoral vein, 1412. external iliac vein, 1412. * internal iliac vein, 1412. collateral branches, 1413. inferior vena cava, 1413. collateral branches, 1413. ovarian veins, 1413. lumbar veins, 1413. portal venous system, 1414.\ninferior mesenteric vein, 1414. splenic vein, 1414. superior mesenteric vein, 1414. hepatic veins, 1414. cardiac veins, 1414.\nVertebral Column. See Supplement.\nVesicula Prostatica, 1415. anatomy, 1415. man, 1415. quadrumana, 1416. volitantia, 1417. insectivora, 1417. fer\u00e6, 1417. pinnipedia, 1418. marsupialia, 1418. rodentia, 1418. cavia cobaya, 1418. edentata, 1419. pachydermata, 1419. solidungula, 1419. ruminantia, 1420. cetacea, 1421. physiology, 1422. morphology, 1423. addendum, 1428.\nVesicvl\u0153 S\u00e9minales, 1429.\ncomparative anatomy, 1430. function, 1431.\nthey are not reservoirs of semen, 1431.\nthey form part of the generative apparatus, 1432.\nVision, 1436. light, 1436.\ndiversified colours arise from the action of matter upon light, 1437.\nbodies divided into transparent and opaque, 1438. spherical and chromatic aberration, 1438. phenomena of vision, 1439.","page":1542},{"file":"p1543.txt","language":"en","ocr_en":"1543\nANALYTICAL INDEX.\nVision (continued).\ndioptric phenomena, 141-0. vision under water, 1441. distinct vision, 1442. duration of impressions, 1444. rapidity of electric light, 1441. dimensions of objects, 1445. magnitude of an object, 1446. erect vision, 1446. single vision, 1447. adaptation to distance, 1450. magnifying lens, 1452. abnormal vision, 1452. achromatopsy, 1452. congenital achromatopsy, 1454. dichromatic, 1454. polychromatic, 1454.\nconfusions of colour ranged in the order of their frequency,according to Wartmann,1456. non-congenital achromatopsy, 1457-permanent achromatopsy, 1457. temporary achromatopsy, 1458.\nremarkable cases, 1458. hyper-chromatopsy, 1461. anorthopia, 1462. myopia or near sight, 1462.\nexciting causes, 1463. presbyopia, 1465.\nuse of suitable glasses, 1466. cylindrical eye, 1467.\nVital Statistics, 1469.\nmean age at death, 1470. rate of mortality, 1473. expectation of life, 1474. mean duration of life, 1474. probable duration of life, 1474.\nVoice, 1475.\nphysiological character of the human vdice ; vibratory movements of the vocal organs; experiments, 1475. falsetto, or voce di testa, 1483. art of singing, 1485.\ncomparative anatomy and physiology of the organs of voice, 1486. mammalia, 1486. quadrumana. 1487. chiroptera, 1488. insectivora, 1489. carnivora, 1489, marsupialia, 1491. rodentia, 1491. edentata, 1492. pachydermata, 1492. ruminantia 1494.\nVoice (continued).\ncetacea, 1494. birds, 1495.\nphysiology of the voice of birds, 1500. voice of reptiles, 1501. insecta, 1503.\nhumming or buzzing of insects, 1504.\nWrist- Joint, 1505.\t.\nbones which constitute the wrist-joint, 1505. radius, 1505.\nscaphoid, semilunar, and cuneiform bones of the carpus, 1506. ligaments, 1506.\nanterior radio- carpal, 1506. posterior radio carpal, 1506. external lateral ligament of the wrist, 1507. internal lateral ligament, 1507. synovial membrane, 1507. mechanical functions, 1507. abnormal condition of the wrist, 1508. congenital, 1508. cases, 1508.\naccident, 1513.\t.\t,\ndislocations of the wrist, and neighbouring radio-ulnar articulations, 1513.\ndislocation of the bones of the forearm backwards, with displacement forwards of the carpus, 1514. luxations of the lower extremity of the ulna, 1514. luxation of the lower extremity of the ulna at the wrist-joint, backwards, 1515. luxation forwards, 1515. luxations of the bones of the carpus, 1516. fractures of the lower extremity of the radius, in the immediate vicinity of the wrist-joint, 1516. symptoms, 1517. diagnosis, 1518.\nanatomical character of the fracture, 1520. fracture of the lower extremity of the ulna, 1521. disjunction of the lower epiphysis of the radius, 1521. cases, 1521.\ndisease : acute arthritis of the radio-carpal and of the inter-carpal articulations, 1523. case, 1524.\nchronic strumous arthritis of the wrist, or white swelling, 1524.\nanatomical characters of chronic strumous arthritis or white swelling of the wrist, 1525. chronic rheumatic arthritis of the wrist, 1526. anatomical characters, 1527. synovial tumours of the region of the wrist, 1528. morbid condition of the synovial burs\u00e6 of the flexor tendons, 1528.\npainful crepitation of tendons around the wrist, 1529.","page":1543},{"file":"z0001.txt","language":"en","ocr_en":"London:\nSpottiswoodes and Shaw, N ew-street- Square.","page":0}],"identifier":"lit29465","issued":"1852","language":"en","pages":"1543","startpages":"1543","title":"The Cyclopaedia of Anatomy and Physiology, vol. 4: Pla [corr.: Ple] - Wri","type":"Book","volume":"4"},"revision":0,"updated":"2022-01-31T13:09:58.075392+00:00"}